Applied Sciences

Editorial

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3 pages, 153 KiB

Open AccessEditorial

Special Issue on Wearable Computing and Machine Learning for Applications in Sports, Health, and Medical Engineering

by Sunghoon I. Lee^1,* and Bjoern M. Eskofier^2,*

¹ College of Information and Computer Sciences, University of Massachusetts Amherst, Amherst, MA 01002, USA

² Department of Computer Science, Friedrich-Alexander University Erlangen-Nuernberg, 91054 Erlangen, Germany

Appl. Sci. 2018, 8(2), 167; https://doi.org/10.3390/app8020167 - 25 Jan 2018

Cited by 3 | Viewed by 3489

Abstract

Recent advancement in digital technologies is driving a remarkable transformation in sports, health, and medical engineering, aiming to achieve the accurate quantification of performance, well-being, and disease condition, and the optimization of sports, clinical, and therapeutic training and treatment programs.[...] Full article

(This article belongs to the Special Issue Wearable Computing and Machine Learning for Applications in Sports, Health, and Medical Engineering)

4 pages, 151 KiB

Open AccessEditorial

Special Issue on Recent Developments of Nanofluids

by Rahmat Ellahi^1,2

¹ Department of Mathematics & Statistics, International Islamic University (IIUI), Islamabad 44000, Pakistan

² Department of Mechanical Engineering, University of California Riverside, Riverside, CA 92521, USA

Appl. Sci. 2018, 8(2), 192; https://doi.org/10.3390/app8020192 - 27 Jan 2018

Cited by 45 | Viewed by 3887

Abstract

Recent advances in nanotechnology have allowed the development of a new category of fluids termed nanofluids. [...]
Full article

(This article belongs to the Special Issue Recent Developments of Nanofluids)

4 pages, 174 KiB

Open AccessEditorial

Special Issue on Modeling, Simulation, Operation and Control of Discrete Event Systems

by Zhiwu Li^1,2

, Mengchu Zhou³

, Naiqi Wu^1,*

and Yi-sheng Huang⁴

¹ Institute of Systems Engineering, Macau University of Science and Technology, Taipa, Macau, China

² School of Electro-Mechanical Engineering, Xidian University, Xi’an 710071, China

³ Department of Electrical and Computer Engineering, New Jersey Institute of Technology, Newark, NJ 07102, USA

⁴ Department of Electrical Engineering, National Ilan University, Yilan County 260, Taiwan

Appl. Sci. 2018, 8(2), 202; https://doi.org/10.3390/app8020202 - 30 Jan 2018

Cited by 4 | Viewed by 3139

Abstract

Information and computer technologies provide the spur to burgeoning man-made, highly automated systems.[...] Full article

(This article belongs to the Special Issue Modeling, Simulation, Operation and Control of Discrete Event Systems)

Research

Jump to: Editorial, Review

13 pages, 2857 KiB

Open AccessArticle

Pipeline Leak Localization Based on FBG Hoop Strain Sensors Combined with BP Neural Network

by Ziguang Jia¹

, Liang Ren^2,*

, Hongnan Li^2,3 and Wei Sun¹

¹ School of Ocean Science and Technology, Dalian University of Technology, Panjin 124221, Liaoning, China

² Faculty of Infrastructure Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China

³ School of Civil Engineering, Shenyang Jianzhu University, Shenyang 110168, Liaoning, China

Appl. Sci. 2018, 8(2), 146; https://doi.org/10.3390/app8020146 - 24 Jan 2018

Cited by 75 | Viewed by 6382

Abstract

Pipelines function as blood vessels serving to bring life-necessities, so their safe usage is one of the foremost concerns. In our previous work, a fiber Bragg grating (FBG) hoop strain sensor with enhanced sensitivity was developed to measure the pressure drop induced by [...] Read more.

Pipelines function as blood vessels serving to bring life-necessities, so their safe usage is one of the foremost concerns. In our previous work, a fiber Bragg grating (FBG) hoop strain sensor with enhanced sensitivity was developed to measure the pressure drop induced by pipeline leakage. Some hoop strain information during the leakage transient process can be extracted from the amount of FBG hoop strain sensors set along the pipeline. In this paper, an integrated approach of a back-propagation (BP) neural network and hoop strain measurement is first proposed to locate the leak points of the pipeline. Five hoop strain variations are employed as input neurons to achieve pattern recognition so as to predict the leakage point. The RMS error can be as low as 1.01% when choosing appropriate hidden layer neurons. Furthermore, the influence of noise on the network’s performance is investigated through superimposing Gaussian noise with a different level. The results demonstrate the feasibility and robustness of the neural network for pipeline leakage localization. Full article

(This article belongs to the Special Issue Fiber Bragg Gratings: Fundamentals, Materials and Applications)

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13 pages, 2432 KiB

Open AccessFeature PaperArticle

Femtosecond Laser Direct Write Integration of Multi-Protein Patterns and 3D Microstructures into 3D Glass Microfluidic Devices

by Daniela Serien¹

, Hiroyuki Kawano², Atsushi Miyawaki², Katsumi Midorikawa¹ and Koji Sugioka^1,*

¹ RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan

² Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan

Appl. Sci. 2018, 8(2), 147; https://doi.org/10.3390/app8020147 - 24 Jan 2018

Cited by 19 | Viewed by 6482

Abstract

Microfluidic devices and biochips offer miniaturized laboratories for the separation, reaction, and analysis of biochemical materials with high sensitivity and low reagent consumption. The integration of functional or biomimetic elements further functionalizes microfluidic devices for more complex biological studies. The recently proposed ship-in-a-bottle [...] Read more.

Microfluidic devices and biochips offer miniaturized laboratories for the separation, reaction, and analysis of biochemical materials with high sensitivity and low reagent consumption. The integration of functional or biomimetic elements further functionalizes microfluidic devices for more complex biological studies. The recently proposed ship-in-a-bottle integration based on laser direct writing allows the construction of microcomponents made of photosensitive polymer inside closed microfluidic structures. Here, we expand this technology to integrate proteinaceous two-dimensional (2D) and three-dimensional (3D) microstructures with the aid of photo-induced cross-linking into glass microchannels. The concept is demonstrated with bovine serum albumin and enhanced green fluorescent protein, each mixed with photoinitiator (Sodium 4-[2-(4-Morpholino) benzoyl-2-dimethylamino] butylbenzenesulfonate). Unlike the polymer integration, fabrication over the entire channel cross-section is challenging. Two proteins are integrated into the same channel to demonstrate multi-protein patterning. Using 50% w/w glycerol solvent instead of 100% water achieves almost the same fabrication resolution for in-channel fabrication as on-surface fabrication due to the improved refractive index matching, enabling the fabrication of 3D microstructures. A glycerol-water solvent also reduces the risk of drying samples. We believe this technology can integrate diverse proteins to contribute to the versatility of microfluidics. Full article

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10 pages, 2224 KiB

Open AccessArticle

Composite Properties and Micromechanical Analysis of Highly Ductile Cement Composite Incorporating Limestone Powder

by Jung Hwan Hyun¹, Bang Yeon Lee²

and Yun Yong Kim^3,*

¹ Department of Civil Engineering, Chungnam National University, Daejeon 34134, Korea

² School of Architecture, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Korea

³ Department of Civil Engineering, Chungnam National University, Daejeon 34134, Korea

Appl. Sci. 2018, 8(2), 151; https://doi.org/10.3390/app8020151 - 23 Jan 2018

Cited by 9 | Viewed by 4308

Abstract

This paper presents the results of an experimental study on the effect of limestone powder on the compressive strength, tensile behavior, and micromechanical parameters of a highly ductile cement composite incorporating limestone powder. Four mixtures were determined according to the replacement ratio of [...] Read more.

This paper presents the results of an experimental study on the effect of limestone powder on the compressive strength, tensile behavior, and micromechanical parameters of a highly ductile cement composite incorporating limestone powder. Four mixtures were determined according to the replacement ratio of cement with limestone powder. A series of experiments including compressive strength, uniaxial tension, single fiber pullout, and matrix toughness tests were performed. Test results showed that the strength (compressive, initial cracking, and tensile strength) decreased, and that the tensile strain capacity increased, with an increase of the replacement ratio of cement with limestone powder. Micromechanical tests and analysis supported the uniaxial tension test result. Full article

(This article belongs to the Section Materials Science and Engineering)

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11 pages, 1663 KiB

Open AccessArticle

All-Carbon Electrodes for Flexible Solar Cells

by Zexia Zhang^1,2,3

, Ruitao Lv^1,2,*, Yi Jia⁴, Xin Gan^1,5

, Hongwei Zhu^1,2 and Feiyu Kang^1,5,*

¹ State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China

² Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China

³ School of Physics and Electronic Engineering, Xinjiang Normal University, Urumqi 830046, Xinjiang Province, China

⁴ Qian Xuesen Laboratory of Space Technology, China Academy of Space Technology, Beijing 100094, China

⁵ Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, Guangdong Province, China

Appl. Sci. 2018, 8(2), 152; https://doi.org/10.3390/app8020152 - 23 Jan 2018

Cited by 29 | Viewed by 6149

Abstract

Transparent electrodes based on carbon nanomaterials have recently emerged as new alternatives to indium tin oxide (ITO) or noble metal in organic photovoltaics (OPVs) due to their attractive advantages, such as long-term stability, environmental friendliness, high conductivity, and low cost. However, it is [...] Read more.

Transparent electrodes based on carbon nanomaterials have recently emerged as new alternatives to indium tin oxide (ITO) or noble metal in organic photovoltaics (OPVs) due to their attractive advantages, such as long-term stability, environmental friendliness, high conductivity, and low cost. However, it is still a challenge to apply all-carbon electrodes in OPVs. Here, we report our efforts to develop all-carbon electrodes in organic solar cells fabricated with different carbon-based materials, including carbon nanotubes (CNTs) and graphene films synthesized by chemical vapor deposition (CVD). Flexible and semitransparent solar cells with all-carbon electrodes are successfully fabricated. The best power conversion efficiency achieved for the devices with all-carbon electrodes is 0.63%, comparable to the reported performance of OPVs using pristine CVD graphene films as anodes on rigid substrates (glass). Moreover, the current densities of as-obtained devices are comparable to those assembled with all-carbon active layers and standard electrodes (e.g., ITO and metal), which indicates that the all-carbon electrodes made of CNT and graphene films are suitably effective for carrier collection and extraction. Our results present the feasibility and potential of applying all-carbon electrodes based on graphitic nanomaterials in next-generation carbon-based photovoltaics. Full article

(This article belongs to the Special Issue Nanostructured Photodetectors and Photovoltaic Devices)

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14 pages, 1298 KiB

Open AccessArticle

Forged Signature Distinction Using Convolutional Neural Network for Feature Extraction

by Seungsoo Nam¹, Hosung Park², Changho Seo¹ and Daeseon Choi^2,*

¹ Department of Convergence Science, Kongju National University, Chungnam 32588, Korea

² Department of Medical Information, Kongju National University, Chungnam 32588, Korea

Appl. Sci. 2018, 8(2), 153; https://doi.org/10.3390/app8020153 - 23 Jan 2018

Cited by 21 | Viewed by 6307

Abstract

This paper proposes a dynamic verification scheme for finger-drawn signatures in smartphones. As a dynamic feature, the movement of a smartphone is recorded with accelerometer sensors in the smartphone, in addition to the moving coordinates of the signature. To extract high-level longitudinal and [...] Read more.

This paper proposes a dynamic verification scheme for finger-drawn signatures in smartphones. As a dynamic feature, the movement of a smartphone is recorded with accelerometer sensors in the smartphone, in addition to the moving coordinates of the signature. To extract high-level longitudinal and topological features, the proposed scheme uses a convolution neural network (CNN) for feature extraction, and not as a conventional classifier. We assume that a CNN trained with forged signatures can extract effective features (called S-vector), which are common in forging activities such as hesitation and delay before drawing the complicated part. The proposed scheme also exploits an autoencoder (AE) as a classifier, and the S-vector is used as the input vector to the AE. An AE has high accuracy for the one-class distinction problem such as signature verification, and is also greatly dependent on the accuracy of input data. S-vector is valuable as the input of AE, and, consequently, could lead to improved verification accuracy especially for distinguishing forged signatures. Compared to the previous work, i.e., the MLP-based finger-drawn signature verification scheme, the proposed scheme decreases the equal error rate by 13.7%, specifically, from 18.1% to 4.4%, for discriminating forged signatures. Full article

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15 pages, 3284 KiB

Open AccessArticle

Enhanced Effective Filtering Approach (eEFA) for Improving HSR Network Performance in Smart Grids

by Nguyen Xuan Tien¹

, Jong Myung Rhee¹ and Sang Yoon Park^2,*

¹ Department of Information and Communications Engineering, Myongji University, 116 Myongji-ro, Yongin, Gyeonggi 17058, Korea

² Department of Electronic Engineering, Myongji University, 116 Myongji-ro, Yongin, Gyeonggi 17058, Korea

Appl. Sci. 2018, 8(2), 154; https://doi.org/10.3390/app8020154 - 23 Jan 2018

Cited by 2 | Viewed by 3579

Abstract

The effective filtering approach (EFA) is one of the most effective approaches for improving the network traffic performance of high-availability seamless redundancy (HSR) networks. However, because EFA uses port locking (PL) for detecting nondestination doubly-attached nodes with HSR protocol (DANH) rings in HSR [...] Read more.

The effective filtering approach (EFA) is one of the most effective approaches for improving the network traffic performance of high-availability seamless redundancy (HSR) networks. However, because EFA uses port locking (PL) for detecting nondestination doubly-attached nodes with HSR protocol (DANH) rings in HSR networks, it forwards the first sent frame to all DANH rings in the network. In addition, it uses a control message for discovering passive QuadBox rings in both unidirectional and bidirectional communications. In this study, we propose an enhanced version of EFA called enhanced-EFA (eEFA) that does not forward unicast frames to nondestination DANH rings. eEFA does not use any control message to discover passive QuadBox rings in bidirectional communications. eEFA thus reduces the network traffic in HSR networks compared with EFA. Analytical and simulation results for a sample network show that the traffic reduction of eEFA was 4–26% and 2–20% for unidirectional and bidirectional communications, respectively, compared to EFA. eEFA, thus, clearly saves network bandwidth and improves the network performance. Full article

(This article belongs to the Special Issue Developing and Implementing Smart Grids: Novel Technologies, Techniques and Models)

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24 pages, 8508 KiB

Open AccessArticle

Hybrid Locomotion Evaluation for a Novel Amphibious Spherical Robot

by Huiming Xing¹

, Shuxiang Guo^1,2,*, Liwei Shi^1,*

, Yanlin He¹, Shuxiang Su¹, Zhan Chen¹ and Xihuan Hou¹

¹ Key Laboratory of Convergence Medical Engineering System and Healthcare Technology, the Ministry of Industry and Information Technology, School of Life Science, Beijing Institute of Technology, Beijing 100081, China

² Faculty of Engineering, Kagawa University, 2217-20 Hayashicho, Takamatsu, Kagawa 761-0396, Japan

Appl. Sci. 2018, 8(2), 156; https://doi.org/10.3390/app8020156 - 24 Jan 2018

Cited by 71 | Viewed by 6884

Abstract

We describe the novel, multiply gaited, vectored water-jet, hybrid locomotion-capable, amphibious spherical robot III (termed ASR-III) featuring a wheel-legged, water-jet composite driving system incorporating a lifting and supporting wheel mechanism (LSWM) and mechanical legs with a water-jet thruster. The LSWM allows the ASR-III [...] Read more.

We describe the novel, multiply gaited, vectored water-jet, hybrid locomotion-capable, amphibious spherical robot III (termed ASR-III) featuring a wheel-legged, water-jet composite driving system incorporating a lifting and supporting wheel mechanism (LSWM) and mechanical legs with a water-jet thruster. The LSWM allows the ASR-III to support the body and slide flexibly on smooth (flat) terrain. The composite driving system facilitates two on-land locomotion modes (sliding and walking) and underwater locomotion mode with vectored thrusters, improving adaptability to the amphibious environment. Sliding locomotion improves the stability and maneuverability of ASR-III on smooth flat terrain, whereas walking locomotion allows ASR-III to conquer rough terrain. We used both forward and reverse kinematic models to evaluate the walking and sliding gait efficiency. The robot can also realize underwater locomotion with four vectored water-jet thrusters, and is capable of forward motion, heading angle control and depth control. We evaluated LSWM efficiency and the sliding velocities associated with varying extensions of the LSWM. To explore gait stability and mobility, we performed on-land experiments on smooth flat terrain to define the optimal stride length and frequency. We also evaluated the efficacy of waypoint tracking when the sliding gait was employed, using a closed-loop proportional-integral-derivative (PID) control mechanism. Moreover, experiments of forward locomotion, heading angle control and depth control were conducted to verify the underwater performance of ASR-III. Comparison of the previous robot and ASR-III demonstrated the ASR-III had better amphibious motion performance. Full article

(This article belongs to the Special Issue Bio-Inspired Robotics)

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8 pages, 4790 KiB

Open AccessArticle

An Experimental Study of the Special Aspects of Scalar-Vector Sound Field Spatial Structures in the Shallow Sea Area

by Yury Morgunov¹, Aleksandr Golov^1,*

, Aleksandr Burenin¹, Peter Unru², Aleksandr Rodionov² and Lubov Statsenko²

¹ V.I. ll’ichev Pacific Oceanological Institute, Primorsky Region, 690041 Vladivostok, Russia

² Department of Electronics and Communications, Far Eastern Federal University, Primorsky Region, 690090 Vladivostok, Russia

Appl. Sci. 2018, 8(2), 157; https://doi.org/10.3390/app8020157 - 24 Jan 2018

Cited by 2 | Viewed by 3028

Abstract

This paper discusses the results of an experimental study of the spatial structure of a scalar-vector sound field formed during towing of a low-frequency acoustic source on the continental shelf of the Sea of Japan. Methodologically, the experiment was carried out by towing [...] Read more.

This paper discusses the results of an experimental study of the spatial structure of a scalar-vector sound field formed during towing of a low-frequency acoustic source on the continental shelf of the Sea of Japan. Methodologically, the experiment was carried out by towing the acoustic source emitting a 134 Hz tone signal at a depth of 20 m on various acoustic paths at distances of up to 10 km from the combined receiving system, which consisted of a sound pressure receiver and three orthogonal sound pressure gradient components. Particular attention was paid to the investigation of the interference structure of scalar and vector fields in controlled hydrological conditions. The quantitative characteristics and features of the formation of signal interference at several depths along the tracks are discussed. The most interesting are the unique results of comparing horizontal and vertical field components, which make it possible to identify the presence of vortex structures in the acoustic source field on several tracks. The possibility of practical application of current research results is analyzed. Full article

(This article belongs to the Special Issue Underwater Acoustics, Communications and Information Processing)

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13 pages, 3350 KiB

Open AccessArticle

Analysis of Xanthine Oxidase Inhibitors from Clerodendranthus spicatus with Xanthine Oxidase Immobilized Silica Coated Fe₃O₄ Nanoparticles

by Liangliang Liu¹, Mengmeng Yuan², Siqi Huang¹, Jianjun Li¹, Defang Li^1,* and Lining Zhao^1,*

¹ Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, Changsha 410205, China

² College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China

Appl. Sci. 2018, 8(2), 158; https://doi.org/10.3390/app8020158 - 24 Jan 2018

Cited by 18 | Viewed by 5180

Abstract

In this study, xanthine oxidase immobilized silica coated Fe₃O₄ nanoparticles (Fe₃O₄@SiO₂-XO) were successfully prepared and characterized by transmission electron microscope, X-ray powder diffraction, Fourier transform infrared spectroscopy and vibrating sample magnetometer. The average diameter [...] Read more.

In this study, xanthine oxidase immobilized silica coated Fe₃O₄ nanoparticles (Fe₃O₄@SiO₂-XO) were successfully prepared and characterized by transmission electron microscope, X-ray powder diffraction, Fourier transform infrared spectroscopy and vibrating sample magnetometer. The average diameter of the Fe₃O₄ nanoparticles was about 300 nm to 350 nm with a shell thickness of 60 nm. The maximum saturation magnetization of the Fe₃O₄@SiO₂-XO nanoparticles was 44.9 emu/g, which ensured the separation from the medium within one minute by using an ordinary magnet. A xanthine oxidase (XO) inhibitor screening method using Fe₃O₄@SiO₂-XO nanoparticles was established and utilized in the extract of Clerodendranthus spicatus. Under the optimized conditions, two compounds were screened out and identified as gardenin B and eupatorin. The half maximal inhibitory concentration (IC₅₀) values of these two compounds were 1.488 μg/mL and 11.197 μg/mL, respectively. The interactions between these two compounds and XO were investigated by the fluorescence spectroscopic method. The results suggested that the quenching effects of gardenin B and eupatorin were due to a static quenching mechanism. Furthermore, gardenin B showed stronger binding capacity than that of eupatorin. In conclusion, this screening method exhibited efficiency and reusability in screening, identification and analysis of enzyme inhibitors from complex mixtures. Full article

(This article belongs to the Special Issue Biological Applications of Magnetic Nanoparticles)

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18 pages, 4875 KiB

Open AccessArticle

Robust Speed Tracking of Induction Motors: An Arduino-Implemented Intelligent Control Approach

by Tan-Jan Ho^*

and Chun-Hao Chang

Department of Electrical Engineering, Chung Yuan Christian University, 200 Chung-Pei Road, Chung-Li District, Taoyuan 32023, Taiwan

Appl. Sci. 2018, 8(2), 159; https://doi.org/10.3390/app8020159 - 24 Jan 2018

Cited by 12 | Viewed by 6466

Abstract

To feasibly achieve economical and satisfactory robust velocity tracking of an induction machine (IM), we propose an Arduino-implemented intelligent speed controller. Because a voltage/frequency controlled IM framework is simple and well suited for being controlled by the proposed speed controller, it is adopted [...] Read more.

To feasibly achieve economical and satisfactory robust velocity tracking of an induction machine (IM), we propose an Arduino-implemented intelligent speed controller. Because a voltage/frequency controlled IM framework is simple and well suited for being controlled by the proposed speed controller, it is adopted herein. Taking into account easy implementation and good performance, we design the controller using a modified Ziegler-Nichols PID (modified Z-N PID) and a fuzzy logic controller (FLC). The modified Z-N PID and the FLC are connected in tandem. The latter is designed based on the output signal of the former for adaptively yielding adequate torque commands. Experimental results of IM velocity tracking controlled by our PC-based and Arduino-based speed controllers consistently show that the proposed design scheme can yield remarkable tracking performance and robustness. In addition, it is demonstrated that the proposed Arduino-implemented controller is not only viable but also effective in terms of cost, size and tracking performance. Full article

(This article belongs to the Special Issue Selected Papers from IEEE ICASI 2017)

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17 pages, 2497 KiB

Open AccessArticle

The Combined Magneto Hydrodynamic and Electric Field Effect on an Unsteady Maxwell Nanofluid Flow over a Stretching Surface under the Influence of Variable Heat and Thermal Radiation

by Hameed Khan¹, Muhammad Haneef¹, Zahir Shah^2,*

, Saeed Islam², Waris Khan³ and Sher Muhammad³

¹ Lab of Theoretical Physics, Department of Physics, Hazara University, Mansehra 21300, KP, Pakistan

² Department of Mathematics, Abdul Wali Khan University, Mardan 23200, KP, Pakistan

³ Department of Mathematics, Islamia College, Peshawar 25000, KP, Pakistan

Appl. Sci. 2018, 8(2), 160; https://doi.org/10.3390/app8020160 - 24 Jan 2018

Cited by 81 | Viewed by 5718

Abstract

The manuscript is a presentation of the combined effect of magnetic and electric field on unsteady flow of Maxwell nanofluid over a stretching surface with thermal radiations. The flow of Maxwell nanofluid is assumed to be in an unsteady state. The basic governing [...] Read more.

The manuscript is a presentation of the combined effect of magnetic and electric field on unsteady flow of Maxwell nanofluid over a stretching surface with thermal radiations. The flow of Maxwell nanofluid is assumed to be in an unsteady state. The basic governing equations changed to a group of differential equations, using proper similarity variables. The obtained modeled equations are nonlinear and coupled. An optimal approach is used to acquire the solution of the modeled problem analytically. The effects of electric field, magnetic field and thermal radiations on Maxwell nanofluid are the main focus in this study. The impact of the Skin friction on velocity profile, Nusselt number on temperature profile and Sherwood number on concentration profile are studied numerically. The influential behavior of the unsteady parameter

λ,

magnetic parameter

M,

electric parameter

E,

radiation parameter

R d,

Maxwell parameter

β,

thermophoresis parameter

N t,

Prandtl number

\Pr,

Schmidt number

S c,

space dependent coefficient

A

and temperature dependent coefficient

B

on the velocity

f (h),

concentration

ϕ (η)

and temperature

θ (η)

are analyzed and studied. The consequences are drawn graphically to see the physical significance of the problem. Full article

(This article belongs to the Special Issue Nanofluids and Their Applications)

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8 pages, 4488 KiB

Open AccessArticle

High Q-Factor Resonance in a Symmetric Array of All-Dielectric Bars

by Chuanshuai Sui, Xiangjun Li, Tingting Lang, Xufeng Jing, Jianjun Liu and Zhi Hong^*

Centre for THz Research, China Jiliang University, Hangzhou 310018, China

Appl. Sci. 2018, 8(2), 161; https://doi.org/10.3390/app8020161 - 24 Jan 2018

Cited by 17 | Viewed by 6661

Abstract

Strong electrical dipole resonance (ER) with high quality-factor (Q) (over several thousands) in a simple silicon all-dielectric rod arrays without asymmetric structure is achieved in the near infrared (NIR) wavelength range. According to numerical simulations, strong high order ER is excited by vertical [...] Read more.

Strong electrical dipole resonance (ER) with high quality-factor (Q) (over several thousands) in a simple silicon all-dielectric rod arrays without asymmetric structure is achieved in the near infrared (NIR) wavelength range. According to numerical simulations, strong high order ER is excited by vertical incident plane waves with electric fields polarized perpendicular to the rod instead of parallel. The electric field coupling between adjacent rods is greatly enhanced by increasing the length of the rods, and the radiative loss of the ER is significantly depressed, thus achieving high Q resonances. In the meantime, the electric field enhancement both inside and surrounding the rod are greatly improved, which is conducive to many applications. The proposed all-dielectric metasurface is simple, low loss, Complementary Metal Oxide Semiconductor (CMOS) compatible, and can be applied in many fields, such as sensing, narrowband filters, optical modulations, and nonlinear interactions. Full article

(This article belongs to the Special Issue Dielectric Metamaterials)

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11 pages, 1202 KiB

Open AccessArticle

Chaos-Based Underwater Communication With Arbitrary Transducers and Bandwidth

by Chao Bai¹, Hai-Peng Ren^1,*, Celso Grebogi^1,2 and Murilo S. Baptista²

¹ Shaanxi Key Laboratory of Complex System Control and Intelligent Information Processing, Xi’an University of Technology, Xi’an 710048, China

² Institute for Complex System and Mathematical Biology, SUPA, University of Aberdeen, Aberdeen AB24 3UE, UK

Appl. Sci. 2018, 8(2), 162; https://doi.org/10.3390/app8020162 - 24 Jan 2018

Cited by 34 | Viewed by 5142

Abstract

In this work, an enhanced differential chaos shift keying (DCSK), based on a first order hybrid chaotic system, is being proposed for a high reliability underwater acoustic communication system. It can be integrated into systems that use standard existing transducers. We show that [...] Read more.

In this work, an enhanced differential chaos shift keying (DCSK), based on a first order hybrid chaotic system, is being proposed for a high reliability underwater acoustic communication system. It can be integrated into systems that use standard existing transducers. We show that a coherent operation between the received signal and the time reversal of the basis function in a first order hybrid chaotic system maximizes the signal to noise ratio at the receiver. Concurrently, DCSK configuration is used to resist the distortion caused by the complex underwater acoustic channel. Our simulation results show that the proposed method has lower bit error rate (BER). In addition, it shows higher communication reliability over underwater acoustic channel as compared to the conventional DCSK using logistic map and its variant forms such as Correlation Delay Shift Keying (CDSK), Phase-Separate DCSK (PS-DCSK), High Efficiency DCSK (HE-DCSK), and Reference Modulated DCSK (RM-DCSK). Full article

(This article belongs to the Special Issue Underwater Acoustics, Communications and Information Processing)

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14 pages, 13158 KiB

Open AccessArticle

Effect of the Addition of Rare Earth Element La on the Tribological Behaviour of AlSi5Cu1Mg Alloy

by Wei Liu^1,2, Hong Yan^1,2,* and Jian-Bin Zhu^1,2

¹ School of Mechanical Electrical Engineering, Nanchang University, Nanchang 330031, China

² Key Laboratory of Light Alloy Preparation & Processing, Nanchang University, Nanchang 330031, China

Appl. Sci. 2018, 8(2), 163; https://doi.org/10.3390/app8020163 - 24 Jan 2018

Cited by 16 | Viewed by 3655

Abstract

The effects of 0, 0.3, 0.6 and 0.9 wt % modifier La on the dry sliding wear behaviours of AlSi5Cu1Mg alloy were investigated under different friction conditions (normal loads, sliding velocities) by using pin-on-disc configuration. The microhardness of the alloys was tested, and [...] Read more.

The effects of 0, 0.3, 0.6 and 0.9 wt % modifier La on the dry sliding wear behaviours of AlSi5Cu1Mg alloy were investigated under different friction conditions (normal loads, sliding velocities) by using pin-on-disc configuration. The microhardness of the alloys was tested, and it was found that the microhardness of the alloys was improved by the La addition. The AlSi5Cu1Mg + 0.6 wt % La alloy exhibited the smallest grain size and maximum microhardness. The wear mechanism analysis of the worn surface was done, which drew support from a scanning electron microscope (SEM) that was equipped with an energy dispersive spectrometer. The results showed that AlSi5Cu1Mg + 0.6 wt % La alloy exhibited the best wear resistance, which was mainly due to the modified grain and microhardness. At the sliding velocity of 0.19 m/s, the adhesive wear became the main wear mechanism with the increase of the load because of the rupture of the oxide layer on the friction surface. Under the load of 3.8 MPa, the abrasive wear became slight as the sliding velocity increasing, due to the recrystallization phenomenon that happened in the frictional surface. Full article

(This article belongs to the Section Materials Science and Engineering)

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8 pages, 1468 KiB

Open AccessArticle

Effect of Meniscus Damping Ratio on Drop-on-Demand Electrohydrodynamic Jetting

by Samuel Haedong Kim¹, Heuiseok Kang², Kyungtae Kang²

, Sang Ho Lee², Kwan Hyun Cho²

and Jun Young Hwang^2,*

¹ Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA

² Korea Institute of Industrial Technology, Cheonan 31056, Korea

Appl. Sci. 2018, 8(2), 164; https://doi.org/10.3390/app8020164 - 24 Jan 2018

Cited by 16 | Viewed by 4078

Abstract

Drop-on-demand (DOD) electrohydrodynamic (EHD) jet printing uses a nozzle and pulsated electric fields to eject small ink droplets of functional material to the appointed spot of a substrate at the appointed time, which offers solutions of high resolution patterning for fabrication of printed [...] Read more.

Drop-on-demand (DOD) electrohydrodynamic (EHD) jet printing uses a nozzle and pulsated electric fields to eject small ink droplets of functional material to the appointed spot of a substrate at the appointed time, which offers solutions of high resolution patterning for fabrication of printed electronics, bioengineering, and display. Because the EHD jet connects fine drops to yield a fine pattern, it is essential to realize high throughput by generating drops quickly and reliably. In this study, the characteristics of jetting frequency were experimentally investigated as a function of nozzle dimensions by measuring response of jetting frequency to pulsating frequency which is varying from 1 Hz to 2000 Hz. The results showed that, even when the nozzle diameter is the same, the other dimensions of the nozzle significantly change the response of jetting to high pulsating frequency. Using a linear damping model describing hydrodynamic motion of ink inside the nozzle, the different behavior of the jetting frequency was explained via the different damping ratio of the oscillating ink: contrary to an underdamped system, an overdamped system supports a jetting frequency higher than the natural frequency. Full article

(This article belongs to the Special Issue Printed Electronics 2017)

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23 pages, 3866 KiB

Open AccessArticle

Production and Maintenance Planning for a Deteriorating System with Operation-Dependent Defectives

by Héctor Rivera-Gómez^*

, Oscar Montaño-Arango, José Ramón Corona-Armenta, Jaime Garnica-González, Eva Selene Hernández-Gress

and Irving Barragán-Vite

Academic Area of Engineering, Autonomous University of Hidalgo, Pachuca-Tulancingo Road km. 4.5, City of Knowledge, Mineral de la Reforma 42184, Hidalgo, Mexico

Appl. Sci. 2018, 8(2), 165; https://doi.org/10.3390/app8020165 - 24 Jan 2018

Cited by 15 | Viewed by 4370

Abstract

This paper provides new insights to the area of sustainable manufacturing systems at analyzing the novel paradigm of integrated production logistics, quality, and maintenance design. For this purpose, we investigate the optimal production and repair/major maintenance switching strategy of an unreliable deteriorating manufacturing [...] Read more.

This paper provides new insights to the area of sustainable manufacturing systems at analyzing the novel paradigm of integrated production logistics, quality, and maintenance design. For this purpose, we investigate the optimal production and repair/major maintenance switching strategy of an unreliable deteriorating manufacturing system. The effects of the deterioration process are mainly observed on the failure intensity and on the quality of the parts produced, where the rate of defectives depends on the production rate. When unplanned failures occur, either a minimal repair or a major maintenance could be conducted. The integration of availability and quality deterioration led us to propose a new stochastic dynamic programming model where optimality conditions are derived through the Hamilton-Jacobi-Bellman equations. The model defined the joint production and repair/major maintenance switching strategies minimizing the total cost over an infinite planning horizon. In the results, the influence of the deterioration process were evident in both the production and maintenances control parameters. A numerical example and an extensive sensitivity analysis were conducted to illustrate the usefulness of the results. Finally, the proposed control policy was compared with alternative strategies based on common assumptions of the literature in order to illustrate its efficiency. Full article

(This article belongs to the Special Issue Smart Sustainable Manufacturing Systems)

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16 pages, 5017 KiB

Open AccessArticle

The Influence of Sensor Size on Acoustic Emission Waveforms—A Numerical Study

by Eleni Tsangouri

and Dimitrios G. Aggelis^*

Department Mechanics of Materials and Constructions (MeMC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium

Appl. Sci. 2018, 8(2), 168; https://doi.org/10.3390/app8020168 - 25 Jan 2018

Cited by 18 | Viewed by 4916

Abstract

The performance of Acoustic Emission technique is governed by the measuring efficiency of the piezoelectric sensors usually mounted on the structure surface. In the case of damage of bulk materials or plates, the sensors receive the acoustic waveforms of which the frequency and [...] Read more.

The performance of Acoustic Emission technique is governed by the measuring efficiency of the piezoelectric sensors usually mounted on the structure surface. In the case of damage of bulk materials or plates, the sensors receive the acoustic waveforms of which the frequency and shape are correlated to the damage mode. This numerical study measures the waveforms received by point, medium and large size sensors and evaluates the effect of sensor size on the acoustic emission signals. Simulations are the only way to quantify the effect of sensor size ensuring that the frequency response of the different sensors is uniform. The cases of horizontal (on the same surface), vertical and diagonal excitation are numerically simulated, and the corresponding elastic wave displacement is measured for different sizes of sensors. It is shown that large size sensors significantly affect the wave magnitude and content in both time and frequency domains and especially in the case of surface wave excitation. The coherence between the original and received waveform is quantified and the numerical findings are experimentally supported. It is concluded that sensors with a size larger than half the size of the excitation wavelength start to seriously influence the accuracy of the AE waveform. Full article

(This article belongs to the Special Issue Damage Inspection of Composite Structures)

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12 pages, 3440 KiB

Open AccessArticle

An Analysis of Angular Indexing Error of a Gear Measuring Machine

by Zhi-Feng Lou¹, Peng-Fei Xue¹, Yuan-Song Zheng¹ and Kuang-Chao Fan^1,2,*

¹ Key Laboratory for Precision and Non-traditional Machining of Ministry of Education, Dalian University of Technology, Dalian 116023, China

² Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan

Appl. Sci. 2018, 8(2), 169; https://doi.org/10.3390/app8020169 - 25 Jan 2018

Cited by 13 | Viewed by 5155

Abstract

In gear measuring machines (GMMs), the tested gear is mounted on a mandrel, which is pivoted at both ends by two centers in a vertical arrangement. The upper center is fixed and the lower center is driven by the spindle of rotation. The [...] Read more.

In gear measuring machines (GMMs), the tested gear is mounted on a mandrel, which is pivoted at both ends by two centers in a vertical arrangement. The upper center is fixed and the lower center is driven by the spindle of rotation. The coaxiality error between the central line of the mandrel and the spindle average line of a GMM always exists in terms of the offset and angle measured in one plane. Such a coaxiality error would cause an angular indexing error of tested gear resulting in measurement error. This phenomenon has rarely been investigated. In this paper, a GMM is taken as an example and its coaxiality error of the mandrel and spindle error of the rotary stage are measured. The difference of rotated angles between the mandrel and spindle is theoretically analyzed by derived formulae. Calibrated by a precision polygon and an autocollimator, the predicted angular index error of the mandrel was consistent with experimental results. Through the experimental verification, it was found that, when the coaxial deviation between the two centers was 10 μm and the lower center tip’s radial motion error was 1.6 μm, the angular indexing deviation of the mandrel was ±5″. If the errors were compensated according to the analyzed model, the residual error was reduced to ±2″. A significant improvement in the angular positioning accuracy of the GMM can be achieved. Full article

(This article belongs to the Section Mechanical Engineering)

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10 pages, 1942 KiB

Open AccessArticle

Self-Q-Switch and CW Operation of a Tunable Dual-Wavelength Er/Yb Double-Clad Fiber Laser

by Baldemar Ibarra-Escamilla¹, Manuel Durán-Sánchez^2,*, Berenice Posada-Ramírez¹, Patricia Prieto-Cortés³, Ricardo I. Álvarez-Tamayo⁴

and Evgeny A. Kuzin¹

¹ Optics Department, Instituto Nacional de Astrofísica, Óptica y Electrónica, L. E. Erro 1, Sta. Ma. Tonantzintla, Puebla 72824, Mexico

² Consejo Nacional de Ciencia y Tecnología (CONACYT)—Optics Department, Instituto Nacional de Astrofísica, Óptica y Electrónica, L. E. Erro 1, Sta. Ma. Tonantzintla, Puebla 72824, Mexico

³ Facultad de Ciencias Físico Matemáticas, Universidad Autónoma de Nuevo León, Av. Universidad S/N, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León 66455, Mexico

⁴ Consejo Nacional de Ciencia y Tecnología (CONACYT)—Facultad de Ciencias Físico Matemáticas, Universidad Autónoma de Nuevo León, Av. Universidad S/N, Ciudad Universitaria, San Nicolás de los Garza, Nuevo Leon 66455, Mexico

Appl. Sci. 2018, 8(2), 171; https://doi.org/10.3390/app8020171 - 25 Jan 2018

Cited by 8 | Viewed by 3717

Abstract

In this paper, a double-clad Er/Yb fiber laser with self-Q-switched and continuous wave operation depending on the pump power range is experimentally demonstrated. The linear cavity is formed on one side by a pair of cascaded tunable fiber Bragg gratings used for the [...] Read more.

In this paper, a double-clad Er/Yb fiber laser with self-Q-switched and continuous wave operation depending on the pump power range is experimentally demonstrated. The linear cavity is formed on one side by a pair of cascaded tunable fiber Bragg gratings used for the selection and tuning of the generated laser lines. On the opposite side, a fiber optical loop mirror with high birefringence fiber in the loop is used to adjust the intra-cavity losses to obtain dual-wavelength emission by temperature changes on the fiber loop. Continuous wave dual-wavelength laser operation is obtained for tunable separation of the generated laser lines in a range from 1 to 7 nm, maximum output power of 3.6Wwith a pump power of 10Wand laser wavelengths linewidth of ~0.2 nm. Self-Q-switched laser pulses are obtained with low pump power in a range from 322 to 890 mW. Q-switched pulses with minimum pulse duration of ~1.5 _s and maximum pulse energy of ~3.5 _J are obtained. Full article

(This article belongs to the Special Issue Erbium-doped Fiber Lasers)

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14 pages, 6368 KiB

Open AccessArticle

Three-Dimensional Identification for Unbalanced Mass of Rotor Systems in Operation

by Huaxia Deng^*, Yifan Diao, Jin Zhang, Peng Zhang, Mengchao Ma

, Xiang Zhong

and Liandong Yu

School of Instrument Science and Opto-electronics Engineering, Hefei University of Technology, No. 193 Tunxi Road, Hefei 230009, China

Appl. Sci. 2018, 8(2), 173; https://doi.org/10.3390/app8020173 - 25 Jan 2018

Cited by 18 | Viewed by 4285

Abstract

Unbalanced mass identification is important for rotor systems. Current methods normally use sensors, which only detect vibration in two-dimensional (2D) space. Actually, the rotor systems vibrate in three-dimensional directions. In this paper, a non-contact method is developed to identify unbalanced mass of rotor [...] Read more.

Unbalanced mass identification is important for rotor systems. Current methods normally use sensors, which only detect vibration in two-dimensional (2D) space. Actually, the rotor systems vibrate in three-dimensional directions. In this paper, a non-contact method is developed to identify unbalanced mass of rotor systems in 3D space. A stereo video system with a pair of synchronized high-speed cameras is established and a feature point is employed to replace traditional contact transducer for measurement. Checkerboard target on a vibration table is used to implement dynamic calibration. The proposed method is compared with eddy current method and laser displacement method. The comparison experiments verify the detection ability of the unbalanced mass for the proposed method. Overall, the proposed method can provide more information than 2D detection methods, which has the great potential for fault diagnosis of rotating machinery. Full article

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10 pages, 2515 KiB

Open AccessArticle

Erythrocyte Membrane Failure by Electromechanical Stress

by E Du^*, Yuhao Qiang and Jia Liu

Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL 33431, USA

Appl. Sci. 2018, 8(2), 174; https://doi.org/10.3390/app8020174 - 25 Jan 2018

Cited by 10 | Viewed by 4533

Abstract

We envision that electrodeformation of biological cells through dielectrophoresis as a new technique to elucidate the mechanistic details underlying membrane failure by electrical and mechanical stresses. Here we demonstrate the full control of cellular uniaxial deformation and tensile recovery in biological cells via [...] Read more.

We envision that electrodeformation of biological cells through dielectrophoresis as a new technique to elucidate the mechanistic details underlying membrane failure by electrical and mechanical stresses. Here we demonstrate the full control of cellular uniaxial deformation and tensile recovery in biological cells via amplitude-modified electric field at radio frequency by an interdigitated electrode array in microfluidics. Transient creep and cyclic experiments were performed on individually tracked human erythrocytes. Observations of the viscoelastic-to-viscoplastic deformation behavior and the localized plastic deformations in erythrocyte membranes suggest that electromechanical stress results in irreversible membrane failure. Examples of membrane failure can be separated into different groups according to the loading scenarios: mechanical stiffening, physical damage, morphological transformation from discocyte to echinocyte, and whole cell lysis. These results show that this technique can be potentially utilized to explore membrane failure in erythrocytes affected by other pathophysiological processes. Full article

(This article belongs to the Special Issue Microsystems for Bio Applications)

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15 pages, 2829 KiB

Open AccessArticle

Application of an Artificial Fish Swarm Algorithm in an Optimum Tuned Mass Damper Design for a Pedestrian Bridge

by Weixing Shi¹, Liangkun Wang¹, Zheng Lu^1,2,*

and Quanwu Zhang³

¹ Research Institute of Structural Engineering and Disaster Reduction, Tongji University, Shanghai 200092, China

² State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, China

³ Shanghai Zhili Vibration Technology Co., Ltd., Shanghai 200092, China

Appl. Sci. 2018, 8(2), 175; https://doi.org/10.3390/app8020175 - 25 Jan 2018

Cited by 42 | Viewed by 5278

Abstract

Tuned mass damper (TMD) has a wide application in the human-induced vibration control of pedestrian bridges and its parameters have great influence on the control effects, hence it should be well designed. A new optimization method for a TMD system is proposed in [...] Read more.

Tuned mass damper (TMD) has a wide application in the human-induced vibration control of pedestrian bridges and its parameters have great influence on the control effects, hence it should be well designed. A new optimization method for a TMD system is proposed in this paper, based on the artificial fish swarm algorithm (AFSA), and the primary structural damping is taken into consideration. The optimization goal is to minimize the maximum dynamic amplification factor of the primary structure under external harmonic excitations. As a result, the optimized TMD has a smaller maximum dynamic amplification factor and better robustness. The optimum TMD parameters for a damped primary structure with different damping ratios and different TMD mass ratios are summarized in a table for simple, practical design, and the fitting equation is also provided. The TMD configuration optimized by the proposed method was shown to be superior to that optimized by other classical optimization methods. Finally, the application of an optimized TMD based on AFSA for a pedestrian bridge is proposed as a case study. The results show that the TMD designed based on AFSA has a smaller maximum dynamic amplification factor than the TMD designed based on the classic Den Hartog method and the TMD designed based on the Ioi Toshihiro method, and the optimized TMD has a good effect in controlling human-induced vibrations at different frequencies. Full article

(This article belongs to the Special Issue Development and Application of Nonlinear Dissipative Device in Structural Vibration Control)

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12 pages, 3201 KiB

Open AccessArticle

Hydrogen Production from Methanol Steam Reforming over TiO₂ and CeO₂ Pillared Clay Supported Au Catalysts

by Rongbin Zhang¹, Chuanqing Huang¹, Lijuan Zong¹, Kun Lu¹, Xuewen Wang¹ and Jianxin Cai^2,*

¹ Department of Chemistry, Institute of Applied Chemistry, Nanchang University, No. 999 Xuefu Road, Nanchang 330031, China

² School of Resources Environmental & Chemical Engineering, Nanchang University, No. 999 Xuefu Road, Nanchang 330031, China

Appl. Sci. 2018, 8(2), 176; https://doi.org/10.3390/app8020176 - 25 Jan 2018

Cited by 31 | Viewed by 4711

Abstract

Abstract: Methanol steam reforming is a promising process for the generation of hydrogen. In this study, Au catalysts supported on modified montmorillonite were prepared and their catalytic activity for methanol steam reforming was investigated at 250–500 °C. The physical and chemical properties [...] Read more.

Abstract: Methanol steam reforming is a promising process for the generation of hydrogen. In this study, Au catalysts supported on modified montmorillonite were prepared and their catalytic activity for methanol steam reforming was investigated at 250–500 °C. The physical and chemical properties of the as-prepared catalysts were characterized by Brunauer–Emmet–Teller method (BET), X-ray diffraction (XRD), transmission electron microscopic (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Inductively Coupled Plasma (ICP), and thermogravimetrc analysis (TGA). For the catalysts examined, Au-Ti-Ce/Na-ABen exhibits the best catalytic performance with methanol conversion of 72% and H₂ selectivity of 99% at 350 °C. This could be attributed to Au, Ce, and Ti species which form a solid solution and move into the interlayer space of the bentonite leading to a high surface area, large average pore volume, large average pore diameter, and small Au particle size. We considered that the synergistic effect of the crosslinking agent, the Ce species, and the Au active sites were responsible for the high activity of Au-Ti-Ce/Na-ABen catalyst for methanol steam reforming. Full article

(This article belongs to the Special Issue Gold Nanoparticles for Catalytic Applications)

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14 pages, 1837 KiB

Open AccessArticle

Chaotic Synchronizing Systems with Zero Time Delay and Free Couple via Iterative Learning Control

by Chun-Kai Cheng

and Paul C. -P. Chao^*

Institute of Electrical and Control Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan

Appl. Sci. 2018, 8(2), 177; https://doi.org/10.3390/app8020177 - 25 Jan 2018

Cited by 7 | Viewed by 3820

Abstract

This study aims to orchestrate a less restrictive learning controller by using the iteration-varying function, the so-called iterative learning controller (ILC), to synchronize two nonlinear systems with free time delay and couple free. The mathematical theories are proven rigorously and controllers are developed [...] Read more.

This study aims to orchestrate a less restrictive learning controller by using the iteration-varying function, the so-called iterative learning controller (ILC), to synchronize two nonlinear systems with free time delay and couple free. The mathematical theories are proven rigorously and controllers are developed for system synchronization, and then an example is forged to demonstrate the effectiveness of synchronization by the designed ILC. The ILC is designed with a feed-forward based by the error dynamics between the two considered nonlinear drive and response systems. The stability of the synchronization facilitated by the designed ILC is ensured by rendering the convergence of an error dynamics that satisfied the Lyapunov function. The Lorenz system within a drive-response system is considered as one system that drives another for the demonstration of the effectiveness of the designed ILC to achieve synchronization and verified initial conditions. Simulations are conducted for the controlled Lorenz system, and the results validated well the expected capability of the designed ILC for synchronization and matched the proposed mathematical theory. Full article

(This article belongs to the Special Issue Selected Papers from IEEE ICASI 2017)

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19 pages, 4965 KiB

Open AccessArticle

A New Resource Allocation Protocol for the Backhaul of Underwater Cellular Wireless Networks

by Changho Yun¹

and Suhan Choi^2,*

¹ Ocean Equipment Research Department Korea Research Institute of Ships & Ocean Engineering (KRISO), Daejeon 34103, Korea

² Department of Mobile Systems Engineering, Dankook University, Yongin 16890, Korea

Appl. Sci. 2018, 8(2), 178; https://doi.org/10.3390/app8020178 - 25 Jan 2018

Cited by 3 | Viewed by 4121

Abstract

In this paper, an underwater base station initiating (UBSI) resource allocation is proposed for underwater cellular wireless networks (UCWNs), which is a new approach to determine the backhaul capacity of underwater base stations (UBSs). This backhaul is a communication link from a UBS [...] Read more.

In this paper, an underwater base station initiating (UBSI) resource allocation is proposed for underwater cellular wireless networks (UCWNs), which is a new approach to determine the backhaul capacity of underwater base stations (UBSs). This backhaul is a communication link from a UBS to a UBS controller (UBSC). Contrary to conventional resource allocation protocols, a UBS initiates to re-determine its backhaul capacity for itself according to its queue status; it releases a portion of its backhaul capacity in the case of experiencing resource under-utilization, and also requests additional backhaul capacity to the UBSC if packet drops are caused due to queue-overflow. This protocol can be appropriate and efficient to the underwater backhaul link where the transmission rate is quite low and the latency is unneglectable. In order to investigate the applicability of the UBSI resource allocation protocol to the UCWN, its performance is extensively analyzed via system level simulations. In our analysis, considered performance measures include average packet drop rate, average resource utilization, average message overhead, and the reserved capacity of the UBSC. In particular, the simulation results show that our proposed protocol not only utilizes most of the given backhaul capacity (more than 90 percent of resource utilization on the average), but also reduces controlling message overheads induced by resource allocation (less than 2 controlling messages on the average). It is expected that the simulation results and analysis in this paper can be used as operating guidelines to apply our new resource allocation protocol for the UCWN. Full article

(This article belongs to the Special Issue Underwater Acoustics, Communications and Information Processing)

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18 pages, 23041 KiB

Open AccessArticle

Frequency Splitting Elimination and Cross-Coupling Rejection of Wireless Power Transfer to Multiple Dynamic Receivers

by Narayanamoorthi R.¹

, Vimala Juliet², Sanjeevikumar Padmanaban³

, Lucian Mihet-Popa^4,*

and Bharatiraja C.¹

¹ Department of Electrical and Electronics Engineering, SRM University, Chennai 603 203, India

² Department of Electronics and Instrumentation Engineering, SRM University, Chennai 603 203, India

³ Department of Energy Technology, Aalborg University, 6700 Esbjerg, Denmark

⁴ Faculty of Engineering, Østfold University College, Kobberslagerstredet 5, 1671 Kråkeroy-Fredrikstad, Norway

Appl. Sci. 2018, 8(2), 179; https://doi.org/10.3390/app8020179 - 26 Jan 2018

Cited by 21 | Viewed by 5668

Abstract

Simultaneous power transfer to multiple receiver (Rx) system is one of the key advantages of wireless power transfer (WPT) system using magnetic resonance. However, determining the optimal condition to uniformly transfer the power to a selected Rx at high efficiency is the challenging [...] Read more.

Simultaneous power transfer to multiple receiver (Rx) system is one of the key advantages of wireless power transfer (WPT) system using magnetic resonance. However, determining the optimal condition to uniformly transfer the power to a selected Rx at high efficiency is the challenging task under the dynamic environment. The cross-coupling and frequency splitting are the dominant issues present in the multiple Rx dynamic WPT system. The existing analysis is performed by considering any one issue present in the system; on the other hand, the cross coupling and frequency splitting issues are interrelated in dynamic Rx’s, which requires a comprehensive design strategy by considering both the problems. This paper proposes an optimal design of multiple Rx WPT system, which can eliminate cross coupling, frequency splitting issues and increase the power transfer efficiency (PTE) of selected Rx. The cross-coupling rejection, uniform power transfer is performed by adding an additional relay coil and independent resonance frequency tuning with capacitive compensation to each Rx unit. The frequency splitting phenomena are eliminated using non-identical transmitter (Tx) and Rx coil structure which can maintain the coupling between the coil under the critical coupling limit. The mathematical analysis of the compensation capacitance calculation and optimal Tx coil size identification is performed for the four Rx WPT system. Finite element analysis and experimental investigation are carried out for the proposed design in static and dynamic conditions. Full article

(This article belongs to the Section Energy Science and Technology)

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23 pages, 9390 KiB

Open AccessArticle

Three-Dimensional Modeling of a Robotic Fish Based on Real Carp Locomotion

by Gonca Ozmen Koca^1,*, Cafer Bal¹

, Deniz Korkmaz²

, Mustafa Can Bingol¹

, Mustafa Ay¹

, Zuhtu Hakan Akpolat¹ and Seda Yetkin³

¹ Department of Mechatronics Engineering, University of Firat, Elazig 23119, Turkey

² Department of Electrical and Electronics Engineering, University of Firat, Elazig 23119, Turkey

³ Department of Electronics and Automation, University of Bitlis Eren, Bitlis 13000, Turkey

Appl. Sci. 2018, 8(2), 180; https://doi.org/10.3390/app8020180 - 26 Jan 2018

Cited by 36 | Viewed by 8067

Abstract

This work focuses on developing a complete non-linear dynamic model comprising entirely kinematic and hydrodynamic effects of Carangiform locomotion based on the Lagrange approach by adapting the parameters and behaviors of a real carp. In order to imitate biological features, swimming patterns of [...] Read more.

This work focuses on developing a complete non-linear dynamic model comprising entirely kinematic and hydrodynamic effects of Carangiform locomotion based on the Lagrange approach by adapting the parameters and behaviors of a real carp. In order to imitate biological features, swimming patterns of a real carp for forward, turning and up-down motions are analyzed by using the Kineova 8.20 software. The proportional optimum link lengths according to actual size, swimming speed, flapping frequency, proportional physical parameters and different swimming motions of the real carp are investigated with the designed robotic fish model. Three-dimensional (3D) locomotion is evaluated by tracking two trajectories in a MATLAB environment. A Reaching Law Control (RLC) approach for inner loop (Euler angles-speed control) and a guidance system for the outer loop (orientation control) are proposed to provide an effective closed-loop control performance. In order to illustrate the 3D performance of the proposed closed loop control system in a virtual reality platform, the designed robotic fish model is also implemented using the Virtual Reality Modeling Language (VRML). Simulation and experimental analysis show that the proposed model gives us significant key solutions to design a fish-like robotic prototype. Full article

(This article belongs to the Special Issue Bio-Inspired Robotics)

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14 pages, 2885 KiB

Open AccessFeature PaperArticle

Impact of Blockage Ratio on Thermal Performance of Delta-Winglet Vortex Generators

by Indri Yaningsih^1,2,3,*

, Agung Tri Wijayanta^2,*, Takahiko Miyazaki^1,3 and Shigeru Koyama^1,3

¹ Department of Energy and Environmental Engineering, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga-shi, Fukuoka 816-8580, Japan

² Department of Mechanical Engineering, Faculty of Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A, Surakarta 57126, Indonesia

³ Thermal Science and Engineering Division, International Institute of Carbon-Neutral Energy Research (I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan

Appl. Sci. 2018, 8(2), 181; https://doi.org/10.3390/app8020181 - 26 Jan 2018

Cited by 21 | Viewed by 5000

Abstract

The impact of double-sided delta-winglet tape (DWTs) inserts on convective heat transfer and friction behaviors in a tube was experimentally investigated. Three DWTs with ratios of winglet-height (b) to inner tube diameter (d_i) called blockage ratio (R [...] Read more.

The impact of double-sided delta-winglet tape (DWTs) inserts on convective heat transfer and friction behaviors in a tube was experimentally investigated. Three DWTs with ratios of winglet-height (b) to inner tube diameter (d_i) called blockage ratio (R_b) of 0.28, 0.35 and 0.42 were tested and their performance was compared to that of a longitudinal strip and plain tube under similar test flow conditions. Experiments were conducted over a wide range of flow rates, 3.35 × 10⁻⁵–8.33 × 10⁻⁵ m³/s, which correspond to 5500 ≤ Reynolds number (Re) ≤ 14,500 in the 14.3 mm i.d. tube. The results revealed that using DWTs dramatically increased the Nusselt number (Nu) by as much as 364.3% and the friction factor (f) by 15.5 times compared with those of a plain tube. Thermal performance (η) increased with a corresponding increase in R_b. The highest thermal performance (η) obtained was 1.4. Showing a notable improvement on the thermal performance of the system, DWTs are proposed as a favorable insert device. Full article

(This article belongs to the Special Issue Sciences in Heat Pump and Refrigeration)

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16 pages, 1076 KiB

Open AccessArticle

An Examination of Thermal Features’ Relevance in the Task of Battery-Fault Detection

by Tomáš Vantuch¹, Jan Fulneček¹, Michael Holuša², Stanislav Mišák^1,* and Jan Vaculík³

¹ Centre ENET at VŠB-TU Ostrava, 708 00 Ostrava, Czech Republic

² Department of Computer Science at VŠB-TU Ostrava, 708 00 Ostrava, Czech Republic

³ E.ON Distribuce, a.s., 370 01 České Budějovice, Czech Republic

Appl. Sci. 2018, 8(2), 182; https://doi.org/10.3390/app8020182 - 26 Jan 2018

Cited by 22 | Viewed by 4192

Abstract

Uninterruptible power supplies (UPS), represented by lead-acid batteries, play an important role in various kinds of industries. They protect industrial technologies from being damaged by dangerous interruptions of an electric power supply. Advanced UPS monitoring performed by a complex battery management system (BMS) [...] Read more.

Uninterruptible power supplies (UPS), represented by lead-acid batteries, play an important role in various kinds of industries. They protect industrial technologies from being damaged by dangerous interruptions of an electric power supply. Advanced UPS monitoring performed by a complex battery management system (BMS) prevents the UPS from sustaining more serious damage due to its timely and accurate battery-fault detection based on voltage metering. This technique is very advanced and precise but also very expensive on a long-term basis. This article describes an experiment applying infrared thermographic measurements during a long term monitoring and fault detection in UPS. The assumption that the battery overheat implies its damaged state is the leading factor of our experiments. They are based on real measured data on various UPS battery sets and several statistical examinations confirming the high relevancy of the thermal features with mostly over 90% detection accuracy. Such a model can be used as a supplement for lead-acid battery based UPS monitoring to ensure their higher reliability under significantly lower maintenance costs. Full article

(This article belongs to the Special Issue Novel Ideas for Infrared Thermography also Applied in Integrated Approaches)

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15 pages, 1801 KiB

Open AccessArticle

Thermal Pre-Treatment of Sewage Sludge in a Lab-Scale Fluidized Bed for Enhancing Its Solid Fuel Properties

by Sujeeta Karki¹, Jeeban Poudel²

and Sea Cheon Oh^1,*

¹ Department of Environmental Engineering, Kongju National University, 1223-24 Cheonan-Daero, Seobuk, Chungnam 330-717, Korea

² Department of Mechanical Engineering, Kongju National University, 1223-24 Cheonan-Daero, Seobuk, Chungnam 330-717, Korea

Appl. Sci. 2018, 8(2), 183; https://doi.org/10.3390/app8020183 - 26 Jan 2018

Cited by 15 | Viewed by 5281

Abstract

Thermal pre-treatment of non-lignocellulosic biomass, sewage sludge, using a lab-scale fluidized bed reactor was carried out in order to enhance its solid fuel properties. The influence of the torrefaction temperature range from 200–350 °C and 0–50 min residence time on the physical and [...] Read more.

Thermal pre-treatment of non-lignocellulosic biomass, sewage sludge, using a lab-scale fluidized bed reactor was carried out in order to enhance its solid fuel properties. The influence of the torrefaction temperature range from 200–350 °C and 0–50 min residence time on the physical and chemical properties of the torrefied product was investigated. Properties of the torrefied product were analyzed on the basis of the degree of torrefaction, ultimate and proximate analysis, and gas analysis. An attempt was made to obtain the chemical exergy of sewage sludge. An elevated torrefaction temperature presented a beneficial impact on the degree of torrefaction and chemical exergy. Moreover, the effect of the torrefaction temperature and residence time on the elemental variation of sewage sludge exhibited an increase in the weight percentage of carbon while the H/C and O/C molar ratios deteriorated. Additionally, the product gas emitted during torrefaction was analyzed to study the pathway of hydrocarbons and oxygen containing compounds. The compounds with oxygen were emitted at higher temperatures in contrast to hydrocarbon gases. In addition, the study of various correlations for predicting the calorific value of torrefied sewage sludge was made. Full article

(This article belongs to the Special Issue Renewable Energy 2018)

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13 pages, 2087 KiB

Open AccessArticle

Wind Power Forecasting Using Multi-Objective Evolutionary Algorithms for Wavelet Neural Network-Optimized Prediction Intervals

by Yanxia Shen^*, Xu Wang and Jie Chen

Key Laboratory of Advanced Process Control for Light Industry, Jiangnan University, Wuxi 214122, China

Appl. Sci. 2018, 8(2), 185; https://doi.org/10.3390/app8020185 - 26 Jan 2018

Cited by 59 | Viewed by 5937

Abstract

The intermittency of renewable energy will increase the uncertainty of the power system, so it is necessary to predict the short-term wind power, after which the electrical power system can operate reliably and safely. Unlike the traditional point forecasting, the purpose of this [...] Read more.

The intermittency of renewable energy will increase the uncertainty of the power system, so it is necessary to predict the short-term wind power, after which the electrical power system can operate reliably and safely. Unlike the traditional point forecasting, the purpose of this study is to quantify the potential uncertainties of wind power and to construct prediction intervals (PIs) and prediction models using wavelet neural network (WNN). Lower upper bound estimation (LUBE) of the PIs is achieved by minimizing a multi-objective function covering both interval width and coverage probabilities. Considering the influence of the points out of the PIs to shorten the width of PIs without compromising coverage probability, a new, improved, multi-objective artificial bee colony (MOABC) algorithm combining multi-objective evolutionary knowledge, called EKMOABC, is proposed for the optimization of the forecasting model. In this paper, some comparative simulations are carried out and the results show that the proposed model and algorithm can achieve higher quality PIs for wind power forecasting. Taking into account the intermittency of renewable energy, such a type of wind power forecast can actually provide a more reliable reference for dispatching of the power system. Full article

(This article belongs to the Special Issue Large Grid-Connected Wind Turbines)

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14 pages, 3772 KiB

Open AccessArticle

Uncertainty Propagation of Spectral Matching Ratios Measured Using a Calibrated Spectroradiometer

by Diego Pavanello^*

, Roberto Galleano

and Robert P. Kenny

Directorate C—Energy, Transport and Climate, European Commission Joint Research Centre, I-21027 Ispra, Italy

Appl. Sci. 2018, 8(2), 186; https://doi.org/10.3390/app8020186 - 26 Jan 2018

Cited by 3 | Viewed by 3076

Abstract

The international standard IEC62670-3 (International Electrotechnical Committee) “Photovoltaic Concentrators (CPV) Performance Testing—Part 3—Performance Measurements and Power Rating” sets the guidelines for power measurements of a CPV device, both in indoor and outdoor conditions. When measuring in outdoor conditions, the acquired data have to [...] Read more.

The international standard IEC62670-3 (International Electrotechnical Committee) “Photovoltaic Concentrators (CPV) Performance Testing—Part 3—Performance Measurements and Power Rating” sets the guidelines for power measurements of a CPV device, both in indoor and outdoor conditions. When measuring in outdoor conditions, the acquired data have to be filtered a posteriori, in order to select only those points measured with ambient conditions close to the Concentrator Standard Operating Conditions (CSOC). The most stringent requirement to be met is related to the three Spectral Matching Ratios (SMR), which have all to be within the limit of 1.00 ± 0.03. SMR are usually determined by the ratio of the currents of component cells to monitor the outdoor spectral ratio conditions during the CPV device power measurements. Experience demonstrates that obtaining real world data meeting these strict conditions is very difficult in practice. However, increasing the acceptable range would make the entire filtering process less appropriate from a physical point of view. Given the importance of correctly measuring the SMR, an estimation of their associated measurement uncertainties is needed to allow a proper assessment of the validity of the 3% limit. In this study a Monte Carlo simulation has been used, to allow the estimation of the propagation of uncertainties in expressions having the and integral form. The method consists of applying both random and wavelength correlated errors to the measured spectra and to the measured spectral responses of the three CPV cell junctions, according to the measurement uncertainties of the European Solar Test Installation (ESTI). The experimental data used in this study have been acquired during clear sky conditions in May 2016, at ESTI’s facilities in Ispra, northern Italy (45°49′ N 8°37′ E). Full article

(This article belongs to the Special Issue Next Generation Photovoltaic Solar Cells)

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15 pages, 3070 KiB

Open AccessEditor’s ChoiceArticle

Energy Management Strategy for a Hybrid Electric Vehicle Based on Deep Reinforcement Learning

by Yue Hu^1,2,3,†, Weimin Li^1,3,4,*, Kun Xu^1,†, Taimoor Zahid^1,2, Feiyan Qin^1,2 and Chenming Li⁵

¹ Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China

² Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Shenzhen 518055, China

³ Jining Institutes of Advanced Technology, Chinese Academy of Sciences, Jining 272000, China

⁴ Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong 999077, China

⁵ Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong 999077, China

^† These authors contributed equally to this work.

Appl. Sci. 2018, 8(2), 187; https://doi.org/10.3390/app8020187 - 26 Jan 2018

Cited by 231 | Viewed by 13411

Abstract

An energy management strategy (EMS) is important for hybrid electric vehicles (HEVs) since it plays a decisive role on the performance of the vehicle. However, the variation of future driving conditions deeply influences the effectiveness of the EMS. Most existing EMS methods simply [...] Read more.

An energy management strategy (EMS) is important for hybrid electric vehicles (HEVs) since it plays a decisive role on the performance of the vehicle. However, the variation of future driving conditions deeply influences the effectiveness of the EMS. Most existing EMS methods simply follow predefined rules that are not adaptive to different driving conditions online. Therefore, it is useful that the EMS can learn from the environment or driving cycle. In this paper, a deep reinforcement learning (DRL)-based EMS is designed such that it can learn to select actions directly from the states without any prediction or predefined rules. Furthermore, a DRL-based online learning architecture is presented. It is significant for applying the DRL algorithm in HEV energy management under different driving conditions. Simulation experiments have been conducted using MATLAB and Advanced Vehicle Simulator (ADVISOR) co-simulation. Experimental results validate the effectiveness of the DRL-based EMS compared with the rule-based EMS in terms of fuel economy. The online learning architecture is also proved to be effective. The proposed method ensures the optimality, as well as real-time applicability, in HEVs. Full article

(This article belongs to the Section Energy Science and Technology)

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21 pages, 51662 KiB

Open AccessArticle

Experimental Study on Punching Performance of Recycled Aggregate Concrete Thin Wallboard with Single-Layer Reinforcement

by Wenchao Liu^1,2, Wanlin Cao^2,*, Nana Zong³, Ruwei Wang² and Lele Ren²

¹ Office of Postdoctoral Research, Beijing University of Technology, Beijing 100124, China

² College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, China

³ Beijing Urban Construction Design & Development Group Co. Limited, Beijing 100034, China

Appl. Sci. 2018, 8(2), 188; https://doi.org/10.3390/app8020188 - 26 Jan 2018

Cited by 5 | Viewed by 3863

Abstract

Recycle Aggregate Concrete (RAC) is a common “green” product used for a variety of purposes, although the durability and strength of the material still need more research to adequately determine influences on these parameters. The failure pattern, punching bearing capacity, and deflection variation [...] Read more.

Recycle Aggregate Concrete (RAC) is a common “green” product used for a variety of purposes, although the durability and strength of the material still need more research to adequately determine influences on these parameters. The failure pattern, punching bearing capacity, and deflection variation of wallboard of both ordinary concrete and RAC with various rebar reinforcement diameters and spacing were analyzed. Based on experimental data, the ABAQUS finite element analysis of the thin wallboard was performed, and the calculated results are in good agreement with the experimental results. The results show that the failure characteristics of ordinary concrete wallboards and RAC wallboards are similar, but the brittleness of the RAC specimens is more significant. Under the same reinforcement ratio, concrete material, whether new or recycled, had little effect on the punching bearing capacity of the specimens. In the case of a low reinforcement ratio, increasing the reinforcement ratio (decreasing the spacing of steel bars) can effectively improve the bearing capacity of the wallboard. Under the same reinforcement ratio, the wallboard with larger diameter and larger spacing has a higher bearing capacity and less deformation after failure. Full article

(This article belongs to the Section Materials Science and Engineering)

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15 pages, 4595 KiB

Open AccessArticle

Monitoring Damage Using Acoustic Emission Source Location and Computational Geometry in Reinforced Concrete Beams

by Jason Maximino C. Ongpeng^1,*

, Andres Winston C. Oreta¹ and Sohichi Hirose²

¹ De La Salle University, 2401 Taft Avenue, Manila 1004, Philippines

² Tokyo Institute of Technology, Meguro Ookayama 2-12-1, Tokyo 152-8552, Japan

Appl. Sci. 2018, 8(2), 189; https://doi.org/10.3390/app8020189 - 26 Jan 2018

Cited by 20 | Viewed by 5151

Abstract

Non-destructive testing in reinforced concrete (RC) for damage detection is still limited to date. In monitoring the damage in RC, 18 beam specimens with varying water cement ratios and reinforcements were casted and tested using a four-point bending test. Repeated step loads were [...] Read more.

Non-destructive testing in reinforced concrete (RC) for damage detection is still limited to date. In monitoring the damage in RC, 18 beam specimens with varying water cement ratios and reinforcements were casted and tested using a four-point bending test. Repeated step loads were designed and at each step load acoustic emission (AE) signals were recorded and processed to obtain the acoustic emission source location (AESL). Computational geometry using a convex hull algorithm was used to determine the maximum volume formed by the AESL inside the concrete beam in relation to the load applied. The convex hull volume (CHV) showed good relation to the damage encountered until 60% of the ultimate load at the midspan was reached, where compression in the concrete occurred. The changes in CHV from 20 to 40% and 20 to 60% load were five and 13 times from CHV of 20% load for all beams, respectively. This indicated that the analysis in three dimensions using CHV was sensitive to damage. In addition, a high water-cement ratio exhibited higher CHV formation compared to a lower water-cement ratio due to its ductility where the movement of AESL becomes wider. Full article

(This article belongs to the Special Issue Soft Computing Techniques in Structural Engineering and Materials)

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21 pages, 5486 KiB

Open AccessArticle

Early Age Carbonation of Fiber-Cement Composites under Real Processing Conditions: A Parametric Investigation

by Bundit Kottititum^1,2, Quoc Tri Phung^2,*

, Norbert Maes², Wichit Prakaypan³ and Thongchai Srinophakun^1,*

¹ Department of Chemical Engineering, Kasetsart University, Bangkok 10900, Thailand

² Institute for Environment, Health, and Safety, Belgian Nuclear Research Centre (SCK•CEN), 2400 Mol, Belgium

³ Mahaphant Fibre-Cement Public Company Limited, Lopburi 15220, Thailand

Appl. Sci. 2018, 8(2), 190; https://doi.org/10.3390/app8020190 - 26 Jan 2018

Cited by 13 | Viewed by 6519

Abstract

This paper presents the outcome of a comprehensive experimental program undertaken to study the performance of cellulose pulp and synthetic PVA (polyvinyl alcohol) based fiber-cement composite under both carbonated and non-carbonated curing conditions at early age. The composites were produced at different rolling [...] Read more.

This paper presents the outcome of a comprehensive experimental program undertaken to study the performance of cellulose pulp and synthetic PVA (polyvinyl alcohol) based fiber-cement composite under both carbonated and non-carbonated curing conditions at early age. The composites were produced at different rolling pressures (2.5 to 9.0 bar) and subjected to various curing conditions in which the effects of CO₂ pressure (1 to 3 bar) and curing time (3 to 9 h) were studied. The mechanical properties (modulus of elasticity (MOE), modulus of rupture (MOR), and toughness), as well as the physical properties (porosity, bulk density, and water absorption), were measured for all samples. Scanning electron microscopy (SEM) was used to investigate the effect of carbonation on porosity change and adhesion of fiber-matrix. A parametric investigation of the effects of the carbonation curing period, CO₂ pressure, and rolling pressure on the improvement of the physical and mechanical properties during carbonation curing was performed. Results showed that fiber-cement composites cured with an elevated CO₂ pressure of 3 bar, rolling pressure of 3 bar, and 5 h of curing time provided optimal curing conditions resulting in the most desirable mechanical and physical properties. However, toughness was greatly reduced with the increase of the CO₂ pressure, curing time, and rolling pressure. Additionally, the carbonation curing improved the bonding between the fiber and the cement matrix because of the precipitation of calcite particularly in the pores of the interfacial transition zone (ITZ) between the cement matrix and the fibers. Full article

(This article belongs to the Special Issue Modelling of Early Age Cracking Risks and Serviceability of Concrete Structures)

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17 pages, 2819 KiB

Open AccessArticle

An Optimal Domestic Electric Vehicle Charging Strategy for Reducing Network Transmission Loss While Taking Seasonal Factors into Consideration

by Yuancheng Zhao^1,2, Yanbo Che¹, Dianmeng Wang¹, Huanan Liu³

, Kun Shi² and Dongmin Yu^3,*

¹ Key Laboratory of Smart Grid of Ministry of Education, Tianjin University, Tianjin 300072, China

² China Electric Power Research Institute, Beijing 100192, China

³ Department of Electrical Engineering, Northeast Electric Power University, Jilin 132012, China

Appl. Sci. 2018, 8(2), 191; https://doi.org/10.3390/app8020191 - 26 Jan 2018

Cited by 13 | Viewed by 4692

Abstract

With the rapid growth of domestic electric vehicle charging loads, the peak-valley gap and power fluctuation rate of power systems increase sharply, which can lead to the increase of network losses and energy efficiency reduction. This paper tries to regulate network loads and [...] Read more.

With the rapid growth of domestic electric vehicle charging loads, the peak-valley gap and power fluctuation rate of power systems increase sharply, which can lead to the increase of network losses and energy efficiency reduction. This paper tries to regulate network loads and reduce power system transmission loss by optimizing domestic electric vehicle charging loads. In this paper, a domestic electric vehicle charging loads model is first developed by analyzing the key factors that can affect users’ charging behavior. Subsequently, the Monte Carlo method is proposed to simulate the power consumption of a cluster of domestic electric vehicles. After that, an optimal electric vehicle charging strategy based on the 0-1 integer programming is presented to regulate network daily loads. Finally, by taking the IEEE33 distributed power system as an example, this paper tries to verify the efficacy of the proposed optimal charging strategy and the necessity for considering seasonal factors when scheduling electric vehicle charging loads. Simulation results show that the proposed 0-1 integer programming method does have good performance in reducing the network peak-valley gap, voltage fluctuation rate, and transmission loss. Moreover, it has some potential to further reduce power system transmission loss when seasonal factors are considered. Full article

(This article belongs to the Special Issue Electric Vehicle Charging)

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27 pages, 17150 KiB

Open AccessArticle

An Automatic Navigation System for Unmanned Surface Vehicles in Realistic Sea Environments

by Xiaojie Sun

, Guofeng Wang^*, Yunsheng Fan

, Dongdong Mu

and Bingbing Qiu

School of Marine Electrical Engineering, Dalian Maritime University, Dalian 116026, China

Appl. Sci. 2018, 8(2), 193; https://doi.org/10.3390/app8020193 - 28 Jan 2018

Cited by 31 | Viewed by 8709

Abstract

In recent years, unmanned surface vehicles (USVs) have received notable attention because of their many advantages in civilian and military applications. To improve the autonomy of USVs, this paper describes a complete automatic navigation system (ANS) with a path planning subsystem (PPS) and [...] Read more.

In recent years, unmanned surface vehicles (USVs) have received notable attention because of their many advantages in civilian and military applications. To improve the autonomy of USVs, this paper describes a complete automatic navigation system (ANS) with a path planning subsystem (PPS) and collision avoidance subsystem (CAS). The PPS based on the dynamic domain tunable fast marching square (DTFMS) method is able to build an environment model from a real electronic chart, where both static and dynamic obstacles are well represented. By adjusting the

S a t u r a t i o n

, the generated path can be changed according to the requirements for security and path length. Then it is used as a guidance trajectory for the CAS through a dynamic target point. In the CAS, according to finite control set model predictive control (FCS-MPC) theory, a collision avoidance control algorithm is developed to track trajectory and avoid collision based on a three-degree of freedom (DOF) planar motion model of USV. Its target point and security evaluation come from the planned path and environmental model of the PPS. Moreover, the prediction trajectory of the CAS can guide changes in the dynamic domain model of the vessel itself. Finally, the system has been tested and validated using the situations of three types of encounters in a realistic sea environment. Full article

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9 pages, 810 KiB

Open AccessArticle

Mathematical Modelling of Nitrate Removal from Water Using a Submerged Membrane Adsorption Hybrid System with Four Adsorbents

by Mahatheva Kalaruban¹, Paripurnanda Loganathan¹, Wang Geun Shim², Jaya Kandasamy¹ and Saravanamuthu Vigneswaran^1,*

¹ Faculty of Engineering, University of Technology Sydney (UTS), P.O. Box 123, Broadway, NSW 2007, Australia

² Department of Polymer Science and Engineering, Sunchon National University, 255 Jungang-Ro, Suncheon-si, Jeollanam-do 57922, Korea

Appl. Sci. 2018, 8(2), 194; https://doi.org/10.3390/app8020194 - 29 Jan 2018

Cited by 8 | Viewed by 4705

Abstract

Excessive concentrations of nitrate in ground water are known to cause human health hazards. A submerged membrane adsorption hybrid system that includes a microfilter membrane and four different adsorbents (Dowex 21K XLT ion exchange resin (Dowex), Fe-coated Dowex, amine-grafted (AG) corn cob and [...] Read more.

Excessive concentrations of nitrate in ground water are known to cause human health hazards. A submerged membrane adsorption hybrid system that includes a microfilter membrane and four different adsorbents (Dowex 21K XLT ion exchange resin (Dowex), Fe-coated Dowex, amine-grafted (AG) corn cob and AG coconut copra) operated at four different fluxes was used to continuously remove nitrate. The experimental data obtained in this study was simulated mathematically with a homogeneous surface diffusion model that incorporated membrane packing density and membrane correlation coefficient, and applied the concept of continuous flow stirred tank reactor. The model fit with experimental data was good. The surface diffusion coefficient was constant for all adsorbents and for all fluxes. The mass transfer coefficient increased with flux for all adsorbents and generally increased with the adsorption capacity of the adsorbents. Full article

(This article belongs to the Special Issue Modeling and Simulations for Membrane Processes of Industrial Interest)

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9 pages, 2139 KiB

Open AccessFeature PaperArticle

Effect of Substrates on the Dynamic Properties of Inkjet-Printed Ag Thin Films

by Deokman Kim^†, Yunsang Kwak^† and Junhong Park^*

¹ Department of Mechanical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea

^† These two authors contributed equally to this work.

Appl. Sci. 2018, 8(2), 195; https://doi.org/10.3390/app8020195 - 29 Jan 2018

Cited by 4 | Viewed by 4105

Abstract

The dynamic properties of inkjet-printed Ag thin films on flexible substrates were measured using flexural wave propagation. The Ag nanoparticle suspension was inkjet-printed on polyimide (PI), silicon wafer, and glass. The effects of flexible substrates on the dynamic properties of the films were [...] Read more.

The dynamic properties of inkjet-printed Ag thin films on flexible substrates were measured using flexural wave propagation. The Ag nanoparticle suspension was inkjet-printed on polyimide (PI), silicon wafer, and glass. The effects of flexible substrates on the dynamic properties of the films were investigated. Beam-shaped Ag-printed substrates were fabricated by pico-second laser pulse cutting. The wave approach was presented to analyze the vibrations of the thin film on the substrates. The Young’s modulus and loss factor of the Ag thin films with the substrates were represented by the combined bending stiffness of the bilayer beam. The vibration response of the base-excited cantilever was measured using an accelerometer and laser Doppler vibrometer (LDV). Vibration transfers were analyzed to obtain dynamic characteristics of the Ag-printed bilayer beam. The substrate affects the reduction of the Ag thin film thickness during the sintering process and surface roughness of the film. The proposed method based on the wave approach allows measurement of the dynamic properties regardless of the ratio of the modulus between the thin film and substrate. Full article

(This article belongs to the Special Issue Printed Electronics 2017)

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11 pages, 5240 KiB

Open AccessArticle

25–34 GHz Single-Pole, Double-Throw CMOS Switches for a Ka-Band Phased-Array Transceiver

by Sangyong Park¹, Jeong-Yun Lee¹, Jong-Yeon Lee¹, Jong-Ryul Yang^2,*

and Donghyun Beak^1,*

¹ School of Electrical Engineering, Chung-Ang University, Seoul 06974, Korea

² Department of Electronic Engineering, Yeungnam University, Gyeongbuk-do 38541, Korea

Appl. Sci. 2018, 8(2), 196; https://doi.org/10.3390/app8020196 - 29 Jan 2018

Cited by 8 | Viewed by 6675

Abstract

This paper presents two single-pole, double-throw (SPDT) mm-wave switches for Ka-band phased-array transceivers, fabricated with a 65-nm complementary metal oxide semiconductor (CMOS) process. One switch employs cross-biasing (CB) control with a single supply, while the other uses dual-supply biasing (DSB) control with positive [...] Read more.

This paper presents two single-pole, double-throw (SPDT) mm-wave switches for Ka-band phased-array transceivers, fabricated with a 65-nm complementary metal oxide semiconductor (CMOS) process. One switch employs cross-biasing (CB) control with a single supply, while the other uses dual-supply biasing (DSB) control with positive and negative voltages. Negative voltages were generated internally, using a ring oscillator and a charge pump. Identical gate and body floated N-type metal oxide semiconductor field effect transistors (N-MOSFETs) in a triple well were used as the switch core transistors. Inductors were used to improve the isolation between the transmitter (TX) and receiver (RX), as well as insertion loss, by canceling the parasitic capacitance of the switch core transistors at resonance. The size of the proposed radio frequency (RF) switch is 260 μm × 230 μm, excluding all pads. The minimum insertion losses of the CB and DSB switches were 2.1 dB at 28 GHz and 1.93 dB at 24 GHz, respectively. Between 25 GHz and 34 GHz, the insertion losses were less than 2.3 dB and 2.5 dB, the return losses were less than 16.7 dB and 17.3 dB, and the isolation was over 18.4 dB and 15.3 dB, respectively. The third order input intercept points (IIP3) of the CB and DSB switches were 38.4 dBm and 39 dBm at 28 GHz, respectively. Full article

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13 pages, 1908 KiB

Open AccessArticle

Robust Sampling Frequency Offset Estimation for OFDM over Frequency Selective Fading Channels

by Yong-An Jung and Young-Hwan You^*

Department of Computer Engineering, Sejong University, Gwangjin-gu, Gunja-dong 98, Seoul 05006, Korea

Appl. Sci. 2018, 8(2), 197; https://doi.org/10.3390/app8020197 - 29 Jan 2018

Cited by 2 | Viewed by 3651

Abstract

Digital radio mondiale (DRM) is a terrestrial radio broadcasting standard to replace existing analogue AM and FM broadcasting, which is based on an orthogonal frequency division multiplexing (OFDM) technique. This paper focuses on the issue of estimating a sampling frequency offset (SFO) in [...] Read more.

Digital radio mondiale (DRM) is a terrestrial radio broadcasting standard to replace existing analogue AM and FM broadcasting, which is based on an orthogonal frequency division multiplexing (OFDM) technique. This paper focuses on the issue of estimating a sampling frequency offset (SFO) in OFDM-based broadcasting systems under frequency selective fading channels. In order to design a robust SFO estimation scheme and to benchmark its performance, the performance of the various conventional SFO estimation schemes is discussed and some improvements on the conventional estimation algorithms are highlighted. The simulation results show that such a design enhances the robustness of the proposed scheme against frequency selective fading. Full article

(This article belongs to the Special Issue Advanced Internet of Things for Smart Infrastructure System)

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12 pages, 982 KiB

Open AccessArticle

Effect of HCV Core Antigen and RNA Clearance during Therapy with Direct Acting Antivirals on Hepatic Stiffness Measured with Shear Wave Elastography in Patients with Chronic Viral Hepatitis C

by Mariusz Łucejko and Robert Flisiak^*

Department of Infectious Diseases and Hepatology, Medical University of Bialystok, 14 Zurawia St; 15-540 Bialystok, Poland

Appl. Sci. 2018, 8(2), 198; https://doi.org/10.3390/app8020198 - 29 Jan 2018

Cited by 5 | Viewed by 3558

Abstract

To assess a combination of novel measures of therapeutic success in the treatment of chronic hepatitis C (CHC) infection, we evaluated liver stiffness (LS) with shear wave elastography and hepatitis C virus core antigen (HCVcAg) concentrations. We followed 34 patients during and after [...] Read more.

To assess a combination of novel measures of therapeutic success in the treatment of chronic hepatitis C (CHC) infection, we evaluated liver stiffness (LS) with shear wave elastography and hepatitis C virus core antigen (HCVcAg) concentrations. We followed 34 patients during and after treatment with direct acting antivirals. All patients achieved a sustained virologic and serologic response and a significant increase of albumin levels. Decreases of alanine aminotransferase (ALT) activity and alpha-fetoprotein (AFP) level were observed during the treatment and follow-up period. A significant decrease in LS was observed between baseline, end of treatment (EOT), and at 24- and 96-week post-treatment follow-up. LS decline between EOT and 96-week follow-up (FU96) was observed in 79% of patients. Significant LS changes were seen in patients with advanced fibrosis, particularly in cirrhotics and in patients with ALT exceeding 100 IU/mL. There was a positive correlation between ALT activity and LS changes at the baseline versus FU96. A negative correlation was demonstrated between individual HCVcAg baseline concentrations and reduction of LS at the baseline versus FU96. In conclusion, we observed that LS significantly declined during and after antiviral treatment. It was accompanied by improvement in some liver function measures, and disappearance of both HCVcAg and HCV ribonucleic acid (HCV RNA). Full article

(This article belongs to the Special Issue Ultrasound Elastography)

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22 pages, 7698 KiB

Open AccessArticle

Statistical, Spatial and Temporal Mapping of 911 Emergencies in Ecuador

by Danilo Corral-De-Witt^1,2,*

, Enrique V. Carrera¹

, Sergio Muñoz-Romero^2,3 and José Luis Rojo-Álvarez^2,3

¹ Departamento de Eléctrica y Electrónica, Universidad de las Fuerzas Armadas ESPE, 171103 Sangolqui, Ecuador

² Departamento de Teoría de la Señal y Comunicaciones, Sistemas Telemáticos y Computación, Universidad Rey Juan Carlos, 28943 Fuenlabrada, Spain

³ Center for Computational Simulation, Universidad Politécnica de Madrid, Boadilla del Monte, 28660 Madrid, Spain

Appl. Sci. 2018, 8(2), 199; https://doi.org/10.3390/app8020199 - 29 Jan 2018

Cited by 6 | Viewed by 4209

Abstract

A public safety answering point (PSAP) receives alerts and attends to emergencies that occur in its responsibility area. The analysis of the events related to a PSAP can give us relevant information in order to manage them and to improve the performance of [...] Read more.

A public safety answering point (PSAP) receives alerts and attends to emergencies that occur in its responsibility area. The analysis of the events related to a PSAP can give us relevant information in order to manage them and to improve the performance of the first response institutions (FRIs) associated to every PSAP. However, current emergency systems are growing dramatically in terms of information heterogeneity and the volume of attended requests. In this work, we propose a system for statistical, spatial, and temporal analysis of incidences registered in a PSAP by using simple, yet robust and compact, event representations. The selected and designed temporal analysis tools include seasonal representations and nonparametric confidence intervals (CIs), which dissociate the main seasonal components and the transients. The spatial analysis tools include a straightforward event location over Google Maps and the detection of heat zones by means of bidimensional geographic Parzen windows with automatic width control in terms of the scales and the number of events in the region of interest. Finally, statistical representations are used for jointly analyzing temporal and spatial data in terms of the “time–space slices”. We analyzed the total number of emergencies that were attended during 2014 by seven FRIs articulated in a PSAP at the Ecuadorian 911 Integrated Security Service. Characteristic weekly patterns were observed in institutions such as the police, health, and transit services, whereas annual patterns were observed in firefighter events. Spatial and spatiotemporal analysis showed some expected patterns together with nontrivial differences among different services, to be taken into account for resource management. The proposed analysis allows for a flexible analysis by combining statistical, spatial and temporal information, and it provides 911 service managers with useful and operative information. Full article

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15 pages, 9576 KiB

Open AccessFeature PaperArticle

Fast Volumetric Ultrasound B-Mode and Doppler Imaging with a New High-Channels Density Platform for Advanced 4D Cardiac Imaging/Therapy

by Lorena Petrusca^1,*, François Varray²

, Rémi Souchon³, Adeline Bernard², Jean-Yves Chapelon³, Hervé Liebgott², William Apoutou N’Djin³

and Magalie Viallon^1,2

¹ University of Lyon, UJM-Saint-Etienne, INSA, CNRS UMR 5520, INSERM U1206, CREATIS, F-42023 Saint-Etienne, France

² University of Lyon, UCBL, INSA, UJM-Saint Etienne, CNRS UMR 5520, INSERM U1206, CREATIS, F-69100 Lyon, France

³ LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003 Lyon, France

Appl. Sci. 2018, 8(2), 200; https://doi.org/10.3390/app8020200 - 29 Jan 2018

Cited by 59 | Viewed by 8973

Abstract

A novel ultrasound (US) high-channels platform is a pre-requisite to open new frontiers in diagnostic and/or therapy by experimental implementation of innovative advanced US techniques. To date, a few systems with more than 1000 transducers permit full and simultaneous control in both transmission [...] Read more.

A novel ultrasound (US) high-channels platform is a pre-requisite to open new frontiers in diagnostic and/or therapy by experimental implementation of innovative advanced US techniques. To date, a few systems with more than 1000 transducers permit full and simultaneous control in both transmission and receiving of all single elements of arrays. A powerful US platform for implementing 4-D (real-time 3-D) advanced US strategies, offering full research access, is presented in this paper. It includes a 1024-elements array prototype designed for 4-D cardiac dual-mode US imaging/therapy and 4 synchronized Vantage systems. The physical addressing of each element was properly chosen for allowing various array downsampled combinations while minimizing the number of driving systems. Numerical simulations of US imaging were performed, and corresponding experimental data were acquired to compare full and downsampled array strategies, testing 4-D imaging sequences and reconstruction processes. The results indicate the degree of degradation of image quality when using full array or downsampled combinations, and the contrast ratio and the contrast to noise ratio vary from 7.71 dB to 2.02 dB and from 2.99 dB to −7.31 dB, respectively. Moreover, the feasibility of the 4-D US platform implementation was tested on a blood vessel mimicking phantom for preliminary Doppler applications. The acquired data with fast volumetric imaging with up to 2000 fps allowed assessing the validity of common 3-D power Doppler, opening in this way a large field of applications. Full article

(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)

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9 pages, 2522 KiB

Open AccessArticle

Nozzle Printed-PEDOT:PSS for Organic Light Emitting Diodes with Various Dilution Rates of Ethanol

by Dai Geon Yoon¹

, MinGyu Kang²

, Jong Beom Kim¹ and Kyung-Tae Kang^1,*

¹ Micro/Nano Process Group, Korea Institute of Technology (KITECH), Sangnok-gu, Ansan-si 15588, Korea

² Program in Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Korea

Appl. Sci. 2018, 8(2), 203; https://doi.org/10.3390/app8020203 - 30 Jan 2018

Cited by 21 | Viewed by 4913

Abstract

In this study, we investigated the ink formulation of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as the hole injection layer (HIL) in an organic light emitting diode (OLED) structure. Generally, in a PEDOT:PSS solution, water is incorporated in the solution for the solution process. However, [...] Read more.

In this study, we investigated the ink formulation of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as the hole injection layer (HIL) in an organic light emitting diode (OLED) structure. Generally, in a PEDOT:PSS solution, water is incorporated in the solution for the solution process. However, the fabrication of thin film which contained the water, main solvent, could not easily form by using printing technology except spin-coating process because of the high surface tension of water. On the other hand, mixing PEDOT:PSS solution and ethanol (EtOH), a dilution solvent, could restrain the non-uniform layer that forms by the high surface tension and low volatility of water. Therefore, we printed a PEDOT:PSS solution with various concentrations of EtOH by using a nozzle printer and obtained a uniform pattern. The line width of PEDOT:PSS diluted with 90% (volume ratio) ehtanol was measured as about 4 mm with good uniformity with a 0.1 mm nozzle. Also, imaging software and a scanning electron microscope (SEM) were used to measure the uniformity of PEDOT:PSS coated on a substrate. Finally, we fabricated a green phosphorescent OLED device with printed-PEDOT:PSS with specific concentrations of EtOH and we achieved a current efficiency of 27 cd/A with uniform quality of luminance in the case of device containing 90% EtOH. Full article

(This article belongs to the Special Issue Printed Electronics 2017)

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13 pages, 2913 KiB

Open AccessFeature PaperArticle

Adaptive Beamformer Combined with Phase Coherence Weighting Applied to Ultrafast Ultrasound

by Michiya Mozumi¹ and Hideyuki Hasegawa^2,*

¹ Faculty of Engineering, University of Toyama, Toyama 930-8555, Japan

² Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan

Appl. Sci. 2018, 8(2), 204; https://doi.org/10.3390/app8020204 - 30 Jan 2018

Cited by 19 | Viewed by 4852

Abstract

Ultrafast ultrasound imaging is a promising technique for measurement of fast moving objects. In ultrafast ultrasound imaging, the high temporal resolution is realized at the expense of the lateral spatial resolution and image contrast. The lateral resolution and image contrast are important factors [...] Read more.

Ultrafast ultrasound imaging is a promising technique for measurement of fast moving objects. In ultrafast ultrasound imaging, the high temporal resolution is realized at the expense of the lateral spatial resolution and image contrast. The lateral resolution and image contrast are important factors determining the quality of a B-mode image, and methods for improvements of the lateral resolution and contrast have been developed. In the present study, we focused on two signal processing techniques; one is an adaptive beamformer, and the other is the phase coherence factor (PCF). By weighting the output of the modified amplitude and phase estimation (mAPES) beamformer by the phase coherence factor, image quality was expected to be improved. In the present study, we investigated how to implement the PCF into the mAPES beamformer. In one of the two examined strategies, the PCF is estimated using element echo signals before application of the weight vector determined by the adaptive beamformer. In the other strategy, the PCF was evaluated from the element signals subjected to the mAPES beamformer weights. The performance of the proposed method was evaluated by the experiments using an ultrasonic imaging phantom. Using the proposed strategies, the lateral full widths at half maximum (FWHM) were both

0.288

mm, which was better than that of 0.348 mm obtained by the mAPES beamformer only. Also, the image contrasts realized by the mAPES beamformer with the PCFs estimated before and after application of the mAPES beamformer weights to the element signals were 5.61 dB and 5.32 dB, respectively, which were better than that of 5.14 dB obtained by the mAPES beamformer only. Full article

(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)

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9 pages, 1219 KiB

Open AccessArticle

Intrinsic Magnetic Properties of Ce₂Fe₁₄B Modified by Al, Ni, or Si

by Kayode Orimoloye¹, Dominic H. Ryan², Frederick E. Pinkerton³ and Mamoun Medraj^1,*

¹ Department of Mechanical, Industrial and Aerospace Engineering, Concordia University, Montreal, QC H3G 1M8, Canada

² Physics Department and Centre for the Physics of Materials, McGill University, Montreal, QC H3A 2T8, Canada

³ Chemical and Materials Systems Lab, General Motors R&D Center, 30500 Mound Rd., Warren, MI 48090, USA

Appl. Sci. 2018, 8(2), 205; https://doi.org/10.3390/app8020205 - 30 Jan 2018

Cited by 13 | Viewed by 4570

Abstract

Intrinsic magnetic properties (saturation magnetization, anisotropy fields, and Curie temperatures) of Ce₂Fe₁₄B doped with Al, Ni, and Si are presented. Substitution for Fe by these elements leads to the formation of solid solutions that crystallize in the tetragonal Nd [...] Read more.

Intrinsic magnetic properties (saturation magnetization, anisotropy fields, and Curie temperatures) of Ce₂Fe₁₄B doped with Al, Ni, and Si are presented. Substitution for Fe by these elements leads to the formation of solid solutions that crystallize in the tetragonal Nd₂Fe₁₄B structure. Substituting Al, Ni, or Si for Fe leads to a decrease in both the saturation magnetization and the anisotropy field of Ce₂Fe₁₄B. Ni and Si increase the Curie temperature of Ce₂Fe₁₄B while Al reduces it. While, for the Ce₂(Fe_14−xT_x)B containing Ni, a maximum Curie temperature of 210 °C was observed at 9 atom % Ni (x = 1.45), the highest value of 252 °C was found for the Ce₂Fe₁₄B containing 14 atom % Si (x = 2.26). Full article

(This article belongs to the Section Materials Science and Engineering)

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13 pages, 1704 KiB

Open AccessFeature PaperArticle

Numerical Model and Experimental Analysis of the Thermal Behavior of Electric Radiant Heating Panels

by Giovanni Ferrarini^1,*

, Stefano Fortuna¹, Alessandro Bortolin¹, Gianluca Cadelano¹, Paolo Bison¹, Fabio Peron² and Piercarlo Romagnoni²

¹ National Research Council–Construction Technologies Institute, Corso Stati Uniti 4, 35127 Padova, Italy

² Department of Design and Planning of Complex Environment–University IUAV of Venezia, Dorsoduro 2206, 30123 Venice, Italy

Appl. Sci. 2018, 8(2), 206; https://doi.org/10.3390/app8020206 - 30 Jan 2018

Cited by 13 | Viewed by 5194

Abstract

Electric radiant heating panels are frequently selected during the design phase of residential and industrial heating systems, especially for retrofit of existing buildings, as an alternative to other common heating systems, such as radiators or air conditioners. The possibility of saving living and [...] Read more.

Electric radiant heating panels are frequently selected during the design phase of residential and industrial heating systems, especially for retrofit of existing buildings, as an alternative to other common heating systems, such as radiators or air conditioners. The possibility of saving living and working space and the ease of installation are the main advantages of electric radiant solutions. This paper investigates the thermal performance of a typical electric radiant panel. A climatic room was equipped with temperature sensors and heat flow meters to perform a steady state experimental analysis. For the dynamic behavior, a mathematical model was created and compared to a thermographic measurement procedure. The results showed for the steady state an efficiency of energy transformation close to one, while in a transient thermal regime the time constant to reach the steady state condition was slightly faster than the typical ones of hydronic systems. Full article

(This article belongs to the Special Issue Novel Ideas for Infrared Thermography also Applied in Integrated Approaches)

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12 pages, 4281 KiB

Open AccessArticle

Thermoelectric Cooling-Aided Bead Geometry Regulation in Wire and Arc-Based Additive Manufacturing of Thin-Walled Structures

by Fang Li

, Shujun Chen^*, Junbiao Shi, Yun Zhao and Hongyu Tian

College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing 100124, China

Appl. Sci. 2018, 8(2), 207; https://doi.org/10.3390/app8020207 - 30 Jan 2018

Cited by 120 | Viewed by 10809

Abstract

Wire and arc-based additive manufacturing (WAAM) is a rapidly developing technology which employs a welding arc to melt metal wire for additive manufacturing purposes. During WAAM of thin-walled structures, as the wall height increases, the heat dissipation to the substrate is slowed down [...] Read more.

Wire and arc-based additive manufacturing (WAAM) is a rapidly developing technology which employs a welding arc to melt metal wire for additive manufacturing purposes. During WAAM of thin-walled structures, as the wall height increases, the heat dissipation to the substrate is slowed down gradually and so is the solidification of the molten pool, leading to variation of the bead geometry. Though gradually reducing the heat input via adjusting the process parameters can alleviate this issue, as suggested by previous studies, it relies on experience to a large extent and inevitably sacrifices the deposition rate because the wire feed rate is directly coupled with the heat input. This study introduces for the first time an in-process active cooling system based on thermoelectric cooling technology into WAAM, which aims to eliminate the difference in heat dissipation between upper and lower layers. The case study shows that, with the aid of thermoelectric cooling, the bead width error is reduced by 56.8%, the total fabrication time is reduced by 60.9%, and the average grain size is refined by 25%. The proposed technique provides new insight into bead geometry regulation during WAAM with various benefits in terms of geometric accuracy, productivity, and microstructure. Full article

(This article belongs to the Special Issue 3D Printing of Metals)

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10 pages, 2560 KiB

Open AccessFeature PaperArticle

Gelatin-Enabled Microsensor for Pancreatic Trypsin Sensing

by George Banis¹

, Luke A. Beardslee² and Reza Ghodssi^1,2,*

¹ Fischell Department of Bioengineering, University of Maryland, 2201 J.M. Patterson Hall, College Park, MD 20742, USA

² Institute for Systems Research, University of Maryland, 2173 A.V. Williams Building, College Park, MD 20742, USA

Appl. Sci. 2018, 8(2), 208; https://doi.org/10.3390/app8020208 - 31 Jan 2018

Cited by 16 | Viewed by 7275

Abstract

Digestive health is critically dependent on the secretion of enzymes from the exocrine pancreas to the duodenum via the pancreatic duct. Specifically, pancreatic trypsin is a major protease responsible for breaking down proteins for absorption in the small intestine. Gelatin-based hydrogels, deposited in [...] Read more.

Digestive health is critically dependent on the secretion of enzymes from the exocrine pancreas to the duodenum via the pancreatic duct. Specifically, pancreatic trypsin is a major protease responsible for breaking down proteins for absorption in the small intestine. Gelatin-based hydrogels, deposited in the form of thin films, have been studied as potential sensor substrates that hydrolyze in the presence of trypsin. In this work, we (1) investigate gelatin as a sensing material; (2) develop a fabrication strategy for coating sensor surfaces; and (3) implement a miniaturized impedance platform for measuring activity levels of pancreatic trypsin. Using impedance spectroscopy, we evaluate gelatin’s specificity and rate of degradation when exposed to a combination of pancreatic enzymes in neutral solution representative of the macromolecular heterogeneity present in the duodenal environment. Our findings suggest gelatin’s preferential degradation to trypsin compared to enzymes such as lipase and amylase. We further observe their interference with trypsin behavior in equivalent concentrations, reducing film digestion by as much as 83% and 77%, respectively. We achieve film patterns in thicknesses ranging from 300–700 nm, which we coat over interdigitated finger electrode sensors. Finally, we test our sensors over several concentrations to emulate the range of pancreatic secretions. Ultimately, our microsensor will serve as the foundation for developing in situ sensors toward diagnosing pancreatic pathologies. Full article

(This article belongs to the Special Issue Microfluidics in Biology and Medicine)

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9 pages, 3007 KiB

Open AccessArticle

Highly Graphitic Carbon Nanofibers Web as a Cathode Material for Lithium Oxygen Batteries

by Hyungkyu Han¹, Yeryung Jeon², Zhiming Liu² and Taeseup Song^2,*

¹ Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University, Slechtitelu 11, 783 71 Olomouc, Czech Republic

² Department of Energy Engineering, Hanyang University, Seoul 133-791, Korea

Appl. Sci. 2018, 8(2), 209; https://doi.org/10.3390/app8020209 - 31 Jan 2018

Cited by 11 | Viewed by 5398

Abstract

The lithium oxygen battery is a promising energy storage system due to its high theoretical energy density and ability to use oxygen from air as a “fuel”. Although various carbonaceous materials have been widely used as a cathode material due to their high [...] Read more.

The lithium oxygen battery is a promising energy storage system due to its high theoretical energy density and ability to use oxygen from air as a “fuel”. Although various carbonaceous materials have been widely used as a cathode material due to their high electronic conductivity and facial processability, previous studies mainly focused on the electrochemical properties associated with the materials (such as graphene and carbon nanotubes) and the electrode configuration. Recent reports demonstrated that the polarization associated with cycling could be significantly increased by lithium carbonates generated from the reaction between the carbon cathode and an electrolyte, which indicates that the physicochemical properties of the carbon cathode could play an important role on the electrochemical performances. However, there is no systematic study to understand these phenomena. Here, we systematically explore the electrochemical properties of carbon nanofibers (CNF) webs with different graphitization degree as a cathode for Li oxygen batteries. The physicochemical properties and electrochemical properties of CNF webs were carefully monitored before and after cycling. CNF webs are prepared at 1000, 1200 and 1400 °C. CNF web pyrolyzed at 1400 °C shows lowered polarization and improved cycle retention compared to those of CNF webs pyrolyzed at 1000 and 1200 °C. Full article

(This article belongs to the Special Issue Advanced Materials for Rechargeable Lithium Batteries)

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15 pages, 1845 KiB

Open AccessArticle

The Derivation of the Stability Bound of the Feedback ANC System That Has an Error in the Estimated Secondary Path Model

by Seong-Pil Moon and Tae-Gyu Chang^*

School of Electrical and Electronic Engineering, Chung-Ang University, Seoul 06974, Korea

Appl. Sci. 2018, 8(2), 210; https://doi.org/10.3390/app8020210 - 31 Jan 2018

Cited by 4 | Viewed by 3945

Abstract

This paper investigates the stability problem of the feedback active noise control (ANC) system, which can be caused by the modeling error of the electro-acoustic path estimation in its feedback mechanism. A stability analysis method is proposed to obtain the stability bound as [...] Read more.

This paper investigates the stability problem of the feedback active noise control (ANC) system, which can be caused by the modeling error of the electro-acoustic path estimation in its feedback mechanism. A stability analysis method is proposed to obtain the stability bound as a form of a closed-form equation in terms of the delay error length of the secondary path, the ANC filter length, and the primary noise frequency. In the proposed method, the system’s open loop magnitude and phase response equations are separately exploited and approximated within the Nyquist stability criterion. The stability bound of the proposed method is verified by comparing both the original Nyquist stability condition and the simulation results. Full article

(This article belongs to the Section Acoustics and Vibrations)

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12 pages, 2242 KiB

Open AccessArticle

Applying FEATHERS for Travel Demand Analysis: Model Considerations

by Qiong Bao^1,*, Bruno Kochan²

, Yongjun Shen^1,2,*, Lieve Creemers², Tom Bellemans², Davy Janssens² and Geert Wets²

¹ School of Transportation, Southeast University, Sipailou 2, Nanjing 210096, China

² Transportation Research Institute (IMOB), Hasselt University, Wetenschapspark 5 bus 6, 3590 Diepenbeek, Belgium

Appl. Sci. 2018, 8(2), 211; https://doi.org/10.3390/app8020211 - 31 Jan 2018

Cited by 7 | Viewed by 3259

Abstract

Activity-based models of travel demand have received considerable attention in transportation planning and forecasting over the last few decades. FEATHERS (The Forecasting Evolutionary Activity-Travel of Households and their Environmental Repercussions), developed by the Transportation Research Institute of Hasselt University, Belgium, is a micro-simulation [...] Read more.

Activity-based models of travel demand have received considerable attention in transportation planning and forecasting over the last few decades. FEATHERS (The Forecasting Evolutionary Activity-Travel of Households and their Environmental Repercussions), developed by the Transportation Research Institute of Hasselt University, Belgium, is a micro-simulation framework developed to facilitate the implementation of activity-based models for transport demand forecasting. In this paper, we focus on several model considerations when applying this framework. First, the way to apply FEATHERS on a more disaggregated geographical level is investigated, with the purpose of obtaining more detailed travel demand information. Next, to reduce the computation time when applying FEATHERS on a more detailed geographical level, an iteration approach is proposed to identify the minimum size of the study area needed. In addition, the effect of stochastic errors inherently included in the FEATHERS framework is investigated, and the concept of confidence intervals is applied to determine the minimum number of model runs needed to minimize this effect. In the application, the FEATHERS framework is used to investigate the potential impact of light rail initiatives on travel demand at a local network in Flanders, Belgium. In doing so, all the aforementioned model considerations are taken into account. The results indicate that by integrating a light rail network into the current public transport network, there would be a relatively positive impact on public transport-related trips, but a relatively negative impact on the non-motorized-mode trips in this area. However, no significant change is found for car-related trips. Full article

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12 pages, 1727 KiB

Open AccessEditor’s ChoiceArticle

Variety Identification of Single Rice Seed Using Hyperspectral Imaging Combined with Convolutional Neural Network

by Zhengjun Qiu^1,2, Jian Chen^1,2, Yiying Zhao^1,2, Susu Zhu^1,2, Yong He^1,2

and Chu Zhang^1,2,*

¹ College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China

² Key Laboratory of Spectroscopy Sensing, Ministry of Agriculture, Hangzhou 310058, China

Appl. Sci. 2018, 8(2), 212; https://doi.org/10.3390/app8020212 - 31 Jan 2018

Cited by 261 | Viewed by 11393

Abstract

The feasibility of using hyperspectral imaging with convolutional neural network (CNN) to identify rice seed varieties was studied. Hyperspectral images of 4 rice seed varieties at two different spectral ranges (380–1030 nm and 874–1734 nm) were acquired. The spectral data at the ranges [...] Read more.

The feasibility of using hyperspectral imaging with convolutional neural network (CNN) to identify rice seed varieties was studied. Hyperspectral images of 4 rice seed varieties at two different spectral ranges (380–1030 nm and 874–1734 nm) were acquired. The spectral data at the ranges of 441–948 nm (Spectral range 1) and 975–1646 nm (Spectral range 2) were extracted. K nearest neighbors (KNN), support vector machine (SVM) and CNN models were built using different number of training samples (100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500 and 3000). KNN, SVM and CNN models in the Spectral range 2 performed slightly better than those in the Spectral range 1. The model performances improved with the increase in the number of training samples. The improvements were not significant when the number of training samples was large. CNN model performed better than the corresponding KNN and SVM models in most cases, which indicated the effectiveness of using CNN to analyze spectral data. The results of this study showed that CNN could be adopted in spectral data analysis with promising results. More varieties of rice need to be studied in future research to extend the use of CNNs in spectral data analysis. Full article

(This article belongs to the Special Issue Hyperspectral Chemical Imaging for Food Authentication)

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11 pages, 3371 KiB

Open AccessArticle

P(VDF-TrFE) Film on PDMS Substrate for Energy Harvesting Applications

by Soaram Kim^1,*, Itmenon Towfeeq¹, Yongchang Dong²

, Sean Gorman¹, Apparao M. Rao² and Goutam Koley¹

¹ Holcombe Department of Electrical and Computer Engineering, Clemson University, Clemson, SC 29634, USA

² Department of Physics and Astronomy and Clemson Nanomaterials Institute, Clemson University, Clemson, SC 29634, USA

Appl. Sci. 2018, 8(2), 213; https://doi.org/10.3390/app8020213 - 31 Jan 2018

Cited by 67 | Viewed by 8075

Abstract

We have developed and demonstrated a highly flexible P(VDF-TrFE) film-based energy harvesting device on a PDMS substrate, avoiding any complex composites and patterned structures. The structural and electrical properties of the P(VDF-TrFE) film was investigated using multiple characterization techniques and an optimized film [...] Read more.

We have developed and demonstrated a highly flexible P(VDF-TrFE) film-based energy harvesting device on a PDMS substrate, avoiding any complex composites and patterned structures. The structural and electrical properties of the P(VDF-TrFE) film was investigated using multiple characterization techniques and an optimized film of 7 µm thickness was used for the energy harvesting application. The device, with Ti/Ni metal contacts, was driven by a shaker providing an acceleration of 1.75 g, and frequencies varying from 5 to 30 Hz. The energy harvesting performance of the final fabricated device was tested using the shaker, and resulted in a maximum output capacitor voltage of 4.4 V, which successfully powered a set of 27 LEDs after several minutes of charging. Full article

(This article belongs to the Special Issue Piezoelectric Energy Harvesting: Materials, Devices and Application)

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25 pages, 2289 KiB

Open AccessArticle

Operation Loop-Based Optimization Model for Resource Allocation to Military Countermeasures versus Probabilistic Threat

by Chunqi Wan^*

, Xiaoxiong Zhang, Qingsong Zhao and Kewei Yang

College of Systems Engineering, National University of Defense Technology, Changsha 410073, China

Appl. Sci. 2018, 8(2), 214; https://doi.org/10.3390/app8020214 - 31 Jan 2018

Cited by 15 | Viewed by 3679

Abstract

Weapons development planning is an unstructured and complex multi-criteria decision-making problem, especially in antagonistic environments. In this paper, the defender’s decision was modelled as a high complexity non-linear optimization problem with limited resources. An operation loop with realistic link rules was first proposed [...] Read more.

Weapons development planning is an unstructured and complex multi-criteria decision-making problem, especially in antagonistic environments. In this paper, the defender’s decision was modelled as a high complexity non-linear optimization problem with limited resources. An operation loop with realistic link rules was first proposed to model the cooperation relationships among weapons in the defense system. The system dynamics principle was used to characterize the dynamic behavior of the nodes in a complex weapons network. Then, we used cumulative threat and development risk to measure different planning solutions by considering the opponent and uncertainties in the development process. Next, an improved Differential Evolution (DE) and Non-Dominated Sorting Differential Evolution (NSDE) were designed to determine the optimal planning solutions for a single objective and multi-objective. The compromise solution, based on the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS), was used to evaluate the Pareto solution set of the multi-objective. Finally, an illustrative case was studied to verify the feasibility and validity of the proposed model. Full article

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16 pages, 2634 KiB

Open AccessArticle

Investigation of Pear Drying Performance by Different Methods and Regression of Convective Heat Transfer Coefficient with Support Vector Machine

by Mehmet Das^1,* and Ebru Kavak Akpinar²

¹ Vocation High School of Ilic Dursun Yildirim, Erzincan University, Ilic, Erzincan 24700, Turkey

² Mechanical Engineering, Faculty of Engineering, Firat University, Elazig 23200, Turkey

Appl. Sci. 2018, 8(2), 215; https://doi.org/10.3390/app8020215 - 31 Jan 2018

Cited by 32 | Viewed by 5282

Abstract

In this study, an air heated solar collector (AHSC) dryer was designed to determine the drying characteristics of the pear. Flat pear slices of 10 mm thickness were used in the experiments. The pears were dried both in the AHSC dryer and under [...] Read more.

In this study, an air heated solar collector (AHSC) dryer was designed to determine the drying characteristics of the pear. Flat pear slices of 10 mm thickness were used in the experiments. The pears were dried both in the AHSC dryer and under the sun. Panel glass temperature, panel floor temperature, panel inlet temperature, panel outlet temperature, drying cabinet inlet temperature, drying cabinet outlet temperature, drying cabinet temperature, drying cabinet moisture, solar radiation, pear internal temperature, air velocity and mass loss of pear were measured at 30 min intervals. Experiments were carried out during the periods of June 2017 in Elazig, Turkey. The experiments started at 8:00 a.m. and continued till 18:00. The experiments were continued until the weight changes in the pear slices stopped. Wet basis moisture content (MCw), dry basis moisture content (MCd), adjustable moisture ratio (MR), drying rate (DR), and convective heat transfer coefficient (h_c) were calculated with both in the AHSC dryer and the open sun drying experiment data. It was found that the values of h_c in both drying systems with a range 12.4 and 20.8 W/m² °C. Three different kernel models were used in the support vector machine (SVM) regression to construct the predictive model of the calculated h_c values for both systems. The mean absolute error (MAE), root mean squared error (RMSE), relative absolute error (RAE) and root relative absolute error (RRAE) analysis were performed to indicate the predictive model’s accuracy. As a result, the rate of drying of the pear was examined for both systems and it was observed that the pear had dried earlier in the AHSC drying system. A predictive model was obtained using the SVM regression for the calculated h_c values for the pear in the AHSC drying system. The normalized polynomial kernel was determined as the best kernel model in SVM for estimating the h_c values. Full article

(This article belongs to the Section Mechanical Engineering)

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10 pages, 6011 KiB

Open AccessArticle

Flower-like BiVO₄ Microspheres and Their Visible Light-Driven Photocatalytic Activity

by Arini Nuran Zulkifili¹, Akira Fujiki² and Shinji Kimijima^2,*

¹ Graduate School of Engineering, Shibaura Institute of Technology, Saitama 337-8570, Japan

² Department of Machinery and Control Systems, Shibaura Institute of Technology, Saitama 337-8570, Japan

Appl. Sci. 2018, 8(2), 216; https://doi.org/10.3390/app8020216 - 31 Jan 2018

Cited by 25 | Viewed by 5096

Abstract

A flower-like BiVO₄ microsphere photocatalyst was synthesized with a simple template-free homogeneous precipitation method at 60 °C for 24 h. The purpose of this study is to explore a low-cost, simple method of synthesizing the self-assembled 3D structure in order to enhance [...] Read more.

A flower-like BiVO₄ microsphere photocatalyst was synthesized with a simple template-free homogeneous precipitation method at 60 °C for 24 h. The purpose of this study is to explore a low-cost, simple method of synthesizing the self-assembled 3D structure in order to enhance photocatalytic performance under visible light irradiation (λ > 420 nm). In this study, the morphology, structure, and photo-absorption of flower-like BiVO₄ microspheres were characterized, and the effects of photocatalysis were analyzed. The results indicate that the size of the flower-like microspheres was about 2 μm to 4 μm and they were composed of several nanosheets. The mechanism of hierarchical microsphere formation has been proposed as the Ostwald ripening process and the self-assembled process. The obtained samples were calcined under different temperatures (300 °C, 400 °C, 500 °C and 600 °C) to study the effects of calcination on the structure and on photocatalysis. The photocatalytic process was then evaluated by decolorization of methylene blue dye under visible-light irradiation. Full article

(This article belongs to the Special Issue Nanotechnology in Wastewater Treatment Technology)

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16 pages, 8158 KiB

Open AccessArticle

Evaluation of Handheld Scanners for Automotive Applications

by Wadea Ameen^*, Abdulrahman M. Al-Ahmari and Syed Hammad Mian

Princess Fatima Alnijiris’s Research Chair for Advanced Manufacturing Technology (FARCAMT Chair), Advanced Manufacturing Institute, King Saud University, Riyadh 11421, Saudi Arabia

Appl. Sci. 2018, 8(2), 217; https://doi.org/10.3390/app8020217 - 31 Jan 2018

Cited by 21 | Viewed by 7361

Abstract

The process of generating a computerized geometric model for an existing part is known as Reverse Engineering (RE). It is a very useful technique in product development and plays a significant role in automotive, aerospace, and medical industries. In fact, it has been [...] Read more.

The process of generating a computerized geometric model for an existing part is known as Reverse Engineering (RE). It is a very useful technique in product development and plays a significant role in automotive, aerospace, and medical industries. In fact, it has been getting remarkable attention in manufacturing industries owing to its advanced data acquisition technologies. The process of RE is based on two primary steps: data acquisition (also known as scanning) and data processing. To facilitate point data acquisition, a variety of scanning systems is available with different capabilities and limitations. Although the optical control of 3D scanners is fully developed, still several factors can affect the quality of the scanned data. As a result, the proper selection of scanning parameters, such as resolution, laser power, shutter time, etc., becomes very crucial. This kind of investigation can be very helpful and provide its users with guidelines to identify the appropriate factors. Moreover, it is worth noting that no single system is ideal in all applications. Accordingly, this work has compared two portable (handheld) systems based on laser scanning and white light optical scanning for automotive applications. A car door containing a free-form surface has been used to achieve the above-mentioned goal. The design of experiments has been employed to determine the effects of different scanning parameters and optimize them. The capabilities and limitations have been identified by comparing the two scanners in terms of accuracy, scanning time, triangle numbers, ease of use, and portability. Then, the relationships between the system capabilities and the application requirements have been established. The results revealed that the laser scanner performed better than the white light scanner in terms of accuracy, while the white light scanner performed better in terms of acquisition speed and triangle numbers. Full article

(This article belongs to the Special Issue Laser Scanning)

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16 pages, 5211 KiB

Open AccessArticle

Comparisons of Energy Management Methods for a Parallel Plug-In Hybrid Electric Vehicle between the Convex Optimization and Dynamic Programming

by Renxin Xiao

, Baoshuai Liu, Jiangwei Shen, Ningyuan Guo, Wensheng Yan and Zheng Chen^*

Faculty of Transportation Engineering, Kunming University of Science and Technology, Kunming 650500, China

Appl. Sci. 2018, 8(2), 218; https://doi.org/10.3390/app8020218 - 31 Jan 2018

Cited by 36 | Viewed by 5891

Abstract

This paper proposes a comparison study of energy management methods for a parallel plug-in hybrid electric vehicle (PHEV). Based on detailed analysis of the vehicle driveline, quadratic convex functions are presented to describe the nonlinear relationship between engine fuel-rate and battery charging power [...] Read more.

This paper proposes a comparison study of energy management methods for a parallel plug-in hybrid electric vehicle (PHEV). Based on detailed analysis of the vehicle driveline, quadratic convex functions are presented to describe the nonlinear relationship between engine fuel-rate and battery charging power at different vehicle speed and driveline power demand. The engine-on power threshold is estimated by the simulated annealing (SA) algorithm, and the battery power command is achieved by convex optimization with target of improving fuel economy, compared with the dynamic programming (DP) based method and the charging depleting–charging sustaining (CD/CS) method. In addition, the proposed control methods are discussed at different initial battery state of charge (SOC) values to extend the application. Simulation results validate that the proposed strategy based on convex optimization can save the fuel consumption and reduce the computation burden obviously. Full article

(This article belongs to the Special Issue Plug-in Hybrid Electric Vehicle (PHEV))

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12 pages, 745 KiB

Open AccessArticle

More Sustainability in Industry through Industrial Internet of Things?

by Grischa Beier^1,*

, Silke Niehoff¹ and Bing Xue^1,2

¹ Institute for Advanced Sustainability Studies (IASS), 14467 Potsdam, Germany

² Institute of Applied Ecology, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China

Appl. Sci. 2018, 8(2), 219; https://doi.org/10.3390/app8020219 - 31 Jan 2018

Cited by 145 | Viewed by 12190

Abstract

Industrial production plays an important role for achieving a green economy and the sustainable development goals. Therefore, the nascent transformation of industrial production due to digitalization into a so-called Industrial Internet of Things (IIoT) is of great interest from a sustainable development point [...] Read more.

Industrial production plays an important role for achieving a green economy and the sustainable development goals. Therefore, the nascent transformation of industrial production due to digitalization into a so-called Industrial Internet of Things (IIoT) is of great interest from a sustainable development point of view. This paper discusses how the environmental dimension of a sustainable development can potentially benefit from the IIoT—focusing especially on three topics: resource efficiency, sustainable energy and transparency. It presents a state of the art literature analysis of IIoT-enabled approaches addressing the three environmental topics. This analysis is compared with the findings of a survey among Chinese industrial companies, investigating the sustainability-related expectations of participants coming along with the implementation of IIoT solutions. China has been chosen as a case study because it brings together a strong industrial sector, ambitious plans regarding industrial digitalization and a high relevance and need for more sustainability. The survey was conducted with the means of a questionnaire which was distributed via email and used for direct on-site interviews. It focused on large and medium sized companies mainly from Liaoning Province and had a sample size of 109 participants. Full article

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17 pages, 4166 KiB

Open AccessArticle

Correlation between Material Properties and Breakage Rate Parameters Determined from Grinding Tests

by Evangelos Petrakis^* and Konstantinos Komnitsas

School of Mineral Resources Engineering, Technical University of Crete, University Campus, Kounoupidiana, 73100 Chania, Greece

Appl. Sci. 2018, 8(2), 220; https://doi.org/10.3390/app8020220 - 31 Jan 2018

Cited by 14 | Viewed by 4000

Abstract

The present study investigates four materials, namely quartz, marble, quartzite and metasandstone and aims to establish correlations, with the use of simple and multiple regression analysis, between their properties and breakage rate parameters. The material properties considered in this study derived from the [...] Read more.

The present study investigates four materials, namely quartz, marble, quartzite and metasandstone and aims to establish correlations, with the use of simple and multiple regression analysis, between their properties and breakage rate parameters. The material properties considered in this study derived from the application of destructive and non-destructive tests and include P-wave velocity (V_p), Schmidt rebound value (R_L), uniaxial compressive strength (UCS) and tangent modulus of elasticity (E_t), while the breakage rate parameters determined from batch grinding tests, include breakage rate S_i, maximum breakage rate S_m, α_T and α, and optimum particle size x_m. The results indicate that the properties of all materials examined show very good correlation and can be used to predict S_i or α_T. Furthermore, parameter α is well correlated with V_p, R_L and E_t using inverse exponential functions, while S_m is strongly correlated with R_L and UCS. Overall, it is deduced that multiple regression analysis involving two independent variables is a reliable approach and can be used to identify correlations between properties and breakage rate parameters for quartz, quartzite and metasandstone, which are silica rich materials. The only exception shown is the determination of x_m for marble. Full article

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23 pages, 3873 KiB

Open AccessArticle

Formal Analysis and Design of Supervisor and User Interface Allowing for Non-Deterministic Choices Using Weak Bi-Simulation

by Shazada Muhammad Umair Khan^1,*

and Wenlong He²

¹ Department of Industrial and Information Engineering, Hanyang University, ERICA Campus, Ansan 15588, Korea

² Department of Mechanical Engineering, Hanyang University, ERICA Campus, Ansan 15588, Korea

Appl. Sci. 2018, 8(2), 221; https://doi.org/10.3390/app8020221 - 31 Jan 2018

Cited by 5 | Viewed by 3674

Abstract

In human machine systems, a user display should contain sufficient information to encapsulate expressive and normative human operator behavior. Failure in such system that is commanded by supervisor can be difficult to anticipate because of unexpected interactions between the different users and machines. [...] Read more.

In human machine systems, a user display should contain sufficient information to encapsulate expressive and normative human operator behavior. Failure in such system that is commanded by supervisor can be difficult to anticipate because of unexpected interactions between the different users and machines. Currently, most interfaces have non-deterministic choices at state of machine. Inspired by the theories of single user of an interface established on discrete event system, we present a formal model of multiple users, multiple machines, a supervisor and a supervisor machine. The syntax and semantics of these models are based on the system specification using timed automata that adheres to desirable specification properties conducive to solving the non-deterministic choices for usability properties of the supervisor and user interface. Further, the succinct interface developed by applying the weak bi-simulation relation, where large classes of potentially equivalent states are refined into a smaller one, enables the supervisor and user to perform specified task correctly. Finally, the proposed approach is applied to a model of a manufacturing system with several users interacting with their machines, a supervisor with several users and a supervisor with a supervisor machine to illustrate the design procedure of human–machine systems. The formal specification is validated by z-eves toolset. Full article

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13 pages, 6155 KiB

Open AccessFeature PaperArticle

Evaluating the Quality of Reinforced Concrete Electric Railway Poles by Thermal Nondestructive Testing

by Dmitry Valeryevich Sannikov¹, Alexander Sergeevich Kolevatov¹, Vladimir Platonovich Vavilov^1,2,* and Marina Valeryevna Kuimova¹

¹ School of Nondestructive Testing and Safety, Tomsk Polytechnic University, Lenin Av., 30, 634050 Tomsk, Russia

² Department of Theoretical and Computational Mechanics, Tomsk State University, Lenin Av., 36, 634050 Tomsk, Russia

Appl. Sci. 2018, 8(2), 222; https://doi.org/10.3390/app8020222 - 1 Feb 2018

Cited by 9 | Viewed by 6584

Abstract

Thermal nondestructive testing can be used to inspect reinforced concrete supports that are widely used in various industries. Corrosion damage is a typical defect found in these supports. Corrosion usually starts as a separation between the concrete and the steel rebar. Damage is [...] Read more.

Thermal nondestructive testing can be used to inspect reinforced concrete supports that are widely used in various industries. Corrosion damage is a typical defect found in these supports. Corrosion usually starts as a separation between the concrete and the steel rebar. Damage is exacerbated by pressure that is caused by the formation of corrosion products. The most logical method for using IR to detect corrosion or a disbond would be to heat up the rebar by resistive or inductive heating. In both cases, monitoring the dynamic temperature distributions on the pole allows for the evaluation of reinforcement quality. The thermal properties of steel, concrete, air, and corrosion products differ greatly. The magnitude of temperature anomalies and their behavior over time depend on the presence of corrosion products, air gaps, and the quality of contact between rebar and concrete. Full article

(This article belongs to the Special Issue Novel Ideas for Infrared Thermography also Applied in Integrated Approaches)

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17 pages, 6102 KiB

Open AccessArticle

Theoretical Analysis of Directly Modulated Reflective Semiconductor Optical Amplifier Performance Enhancement by Microring Resonator-Based Notch Filtering

by Zoe V. Rizou^* and Kyriakos E. Zoiros

Lightwave Communications Research Group, Laboratory of Telecommunications Systems, Department of Electrical and Computer Engineering, Democritus University of Thrace, 67 100 Xanthi, Greece

Appl. Sci. 2018, 8(2), 223; https://doi.org/10.3390/app8020223 - 1 Feb 2018

Cited by 19 | Viewed by 4832

Abstract

We demonstrate the feasibility of using a single microring resonator (MRR) as optical notch filter for enabling the direct modulation of a reflective semiconductor optical amplifier (RSOA) at more than tripled data rate than possible with the RSOA alone. We conduct a thorough [...] Read more.

We demonstrate the feasibility of using a single microring resonator (MRR) as optical notch filter for enabling the direct modulation of a reflective semiconductor optical amplifier (RSOA) at more than tripled data rate than possible with the RSOA alone. We conduct a thorough simulation analysis to investigate and assess the impact of critical operating parameters on defined performance metrics, and we specify how the former must be selected so that the latter can become acceptable. By using an MRR of appropriate radius and detuning, the RSOA modulation bandwidth, which we explicitly quantify, can be extended to overcome the RSOA pattern-dependent performance limitations. Thus, the MRR makes the RSOA-encoded signal exhibit improved characteristics that can be exploited in practical RSOA direct modulation applications. Full article

(This article belongs to the Special Issue Applications of Semiconductor Optical Amplifiers)

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11 pages, 5488 KiB

Open AccessArticle

Kernel-Density-Based Particle Defect Management for Semiconductor Manufacturing Facilities

by Seung Hwan Park^†, Sehoon Kim^† and Jun-Geol Baek^*

¹ Department of Industrial Management Engineering, Korea University, Seoul 02841, Korea

^† Those authors contributed equally to this work.

Appl. Sci. 2018, 8(2), 224; https://doi.org/10.3390/app8020224 - 1 Feb 2018

Cited by 10 | Viewed by 12907

Abstract

In a semiconductor manufacturing process, defect cause analysis is a challenging task because the process includes consecutive fabrication phases involving numerous facilities. Recently, in accordance with the shrinking chip pitches, fabrication (FAB) processes require advanced facilities and designs for manufacturing microcircuits. However, the [...] Read more.

In a semiconductor manufacturing process, defect cause analysis is a challenging task because the process includes consecutive fabrication phases involving numerous facilities. Recently, in accordance with the shrinking chip pitches, fabrication (FAB) processes require advanced facilities and designs for manufacturing microcircuits. However, the sizes of the particle defects remain constant, in spite of the increasing modernization of the facilities. Consequently, this increases the particle defect ratio. Therefore, this study proposes a particle defect management method for the reduction of the defect ratio. The proposed method provides a kernel-density-based particle map that can overcome the limitations of the conventional method. The method consists of two phases. The first phase is the acquisition of cumulative coordinates of the defect locations on the wafer using the FAB database. Subsequently, this cumulative data is used to generate a particle defect map based on the estimation of kernel density; this map establishes the advanced monitoring statistics. In order to validate this method, we conduct an experiment for comparison with the previous industrial method. Full article

(This article belongs to the Special Issue Smart Sustainable Manufacturing Systems)

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14 pages, 367 KiB

Open AccessArticle

Target Localization in Underwater Acoustic Sensor Networks Using RSS Measurements

by Shengming Chang¹, Youming Li^1,*, Yucheng He²

and Hui Wang¹

¹ Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo 315211, China

² Xiamen Key Laboratory of Mobile Multimedia Communications, Huaqiao University, 668 Jimei Avenue, Xiamen 361021, China

Appl. Sci. 2018, 8(2), 225; https://doi.org/10.3390/app8020225 - 1 Feb 2018

Cited by 55 | Viewed by 4964

Abstract

This paper addresses the target localization problems based on received signal strength (RSS) measurements in underwater acoustic wireless sensor network (UWSN). Firstly, the problems based on the maximum likelihood (ML) criterion for estimating target localization in cases of both known and unknown transmit [...] Read more.

This paper addresses the target localization problems based on received signal strength (RSS) measurements in underwater acoustic wireless sensor network (UWSN). Firstly, the problems based on the maximum likelihood (ML) criterion for estimating target localization in cases of both known and unknown transmit power are respectively derived, and fast implementation algorithms are proposed by transforming the non-convex problems into a generalized trust region subproblem (GTRS) frameworks. A three-step procedure is also provided to enhance the estimation accuracy in the unknown target transmit power case. Furthermore, the Cramer–Rao lower bounds (CRLBs) in both cases are derived. Computer simulation results show the superior performance of the proposed methods in the underwater environment. Full article

(This article belongs to the Special Issue Underwater Acoustics, Communications and Information Processing)

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15 pages, 40278 KiB

Open AccessArticle

Stay True to the Sound of History: Philology, Phylogenetics and Information Engineering in Musicology

by Sebastiano Verde

, Niccolò Pretto^*

, Simone Milani

and Sergio Canazza

Department of Information Engineering, University of Padova, via Gradenigo 6/B, 35131 Padova, Italy

Appl. Sci. 2018, 8(2), 226; https://doi.org/10.3390/app8020226 - 1 Feb 2018

Cited by 21 | Viewed by 5327

Abstract

This work investigates computational musicology for the study of tape music works tackling the problems concerning stemmatics. These philological problems have been analyzed with an innovative approach considering the peculiarities of audio tape recordings. The paper presents a phylogenetic reconstruction strategy that relies [...] Read more.

This work investigates computational musicology for the study of tape music works tackling the problems concerning stemmatics. These philological problems have been analyzed with an innovative approach considering the peculiarities of audio tape recordings. The paper presents a phylogenetic reconstruction strategy that relies on digitizing the analyzed tapes and then converting each audio track into a two-dimensional spectrogram. This conversion allows adopting a set of computer vision tools to align and equalize different tracks in order to infer the most likely transformation that converts one track into another. In the presented approach, the main editing techniques, intentional and unintentional alterations and different configurations of a tape recorded are estimated in phylogeny analysis. The proposed solution presents a satisfying robustness to the adoption of the wrong reading setup together with a good reconstruction accuracy of the phylogenetic tree. The reconstructed dependencies proved to be correct or plausible in 90% of the experimental cases. Full article

(This article belongs to the Special Issue Sound and Music Computing)

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16 pages, 8657 KiB

Open AccessFeature PaperArticle

High-Frame-Rate Doppler Ultrasound Using a Repeated Transmit Sequence

by Anthony S. Podkowa^1,*, Michael L. Oelze¹ and Jeffrey A. Ketterling²

¹ Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA

² Lizzi Center for Biomedical Engineering, Riverside Research Institute, New York, NY 10038, USA

Appl. Sci. 2018, 8(2), 227; https://doi.org/10.3390/app8020227 - 1 Feb 2018

Cited by 15 | Viewed by 5053

Abstract

The maximum detectable velocity of high-frame-rate color flow Doppler ultrasound is limited by the imaging frame rate when using coherent compounding techniques. Traditionally, high quality ultrasonic images are produced at a high frame rate via coherent compounding of steered plane wave reconstructions. However, [...] Read more.

The maximum detectable velocity of high-frame-rate color flow Doppler ultrasound is limited by the imaging frame rate when using coherent compounding techniques. Traditionally, high quality ultrasonic images are produced at a high frame rate via coherent compounding of steered plane wave reconstructions. However, this compounding operation results in an effective downsampling of the slow-time signal, thereby artificially reducing the frame rate. To alleviate this effect, a new transmit sequence is introduced where each transmit angle is repeated in succession. This transmit sequence allows for direct comparison between low resolution, pre-compounded frames at a short time interval in ways that are resistent to sidelobe motion. Use of this transmit sequence increases the maximum detectable velocity by a scale factor of the transmit sequence length. The performance of this new transmit sequence was evaluated using a rotating cylindrical phantom and compared with traditional methods using a 15-MHz linear array transducer. Axial velocity estimates were recorded for a range of

\pm 300

mm/s and compared to the known ground truth. Using these new techniques, the root mean square error was reduced from over 400 mm/s to below 50 mm/s in the high-velocity regime compared to traditional techniques. The standard deviation of the velocity estimate in the same velocity range was reduced from 250 mm/s to 30 mm/s. This result demonstrates the viability of the repeated transmit sequence methods in detecting and quantifying high-velocity flow. Full article

(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)

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16 pages, 1208 KiB

Open AccessArticle

Comparison of Training Approaches for Photovoltaic Forecasts by Means of Machine Learning

by Alberto Dolara^†, Francesco Grimaccia^†

, Sonia Leva^†

, Marco Mussetta^†

and Emanuele Ogliari^*,†

¹ Dipartimento di Energia, Politecnico di Milano, via La Masa 34, 20156 Milano, Italy

^† These authors contributed equally to this work.

Appl. Sci. 2018, 8(2), 228; https://doi.org/10.3390/app8020228 - 2 Feb 2018

Cited by 53 | Viewed by 5757

Abstract

The relevance of forecasting in renewable energy sources (RES) applications is increasing, due to their intrinsic variability. In recent years, several machine learning and hybrid techniques have been employed to perform day-ahead photovoltaic (PV) output power forecasts. In this paper, the authors present [...] Read more.

The relevance of forecasting in renewable energy sources (RES) applications is increasing, due to their intrinsic variability. In recent years, several machine learning and hybrid techniques have been employed to perform day-ahead photovoltaic (PV) output power forecasts. In this paper, the authors present a comparison of the artificial neural network’s main characteristics used in a hybrid method, focusing in particular on the training approach. In particular, the influence of different data-set composition affecting the forecast outcome have been inspected by increasing the training dataset size and by varying the training and validation shares, in order to assess the most effective training method of this machine learning approach, based on commonly used and a newly-defined performance indexes for the prediction error. The results will be validated over a one-year time range of experimentally measured data. Novel error metrics are proposed and compared with traditional ones, showing the best approach for the different cases of either a newly deployed PV plant or an already-existing PV facility. Full article

(This article belongs to the Special Issue Computational Intelligence in Photovoltaic Systems)

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14 pages, 3126 KiB

Open AccessArticle

¹H-NMR Spectroscopy: A Possible Approach to Advanced Bitumen Characterization for Industrial and Paving Applications

by Cesare Oliviero Rossi^1,*

, Paolino Caputo¹

, Giuseppina De Luca^1,*

, Loredana Maiuolo¹, Shahin Eskandarsefat² and Cesare Sangiorgi²

¹ Department of Chemistry and Chemical Technologies, University of Calabria, Ponte P. Bucci, Arcavacata di Rende, 87036 Cosenza, Italy

² DICAM-Roads, Deptartment of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, V.le Risorgimento 2, 40136 Bologna, Italy

Appl. Sci. 2018, 8(2), 229; https://doi.org/10.3390/app8020229 - 2 Feb 2018

Cited by 55 | Viewed by 7897

Abstract

Bitumen has unique chemo-mechanical properties, and for this reason, it is today one of the main constituents of many industrial products beside its common use in highway pavements construction. While the excellent rheological properties of bitumens have been investigated by means of different [...] Read more.

Bitumen has unique chemo-mechanical properties, and for this reason, it is today one of the main constituents of many industrial products beside its common use in highway pavements construction. While the excellent rheological properties of bitumens have been investigated by means of different techniques, much remains to be known about the intrinsic properties of this complex material. It is therefore important to investigate its structure and properties from a closer point of view, towards possible useful modifications of the neat material. The present research developed a technique to investigate the composition of bitumens using Thin Layer Chromatography (TLC) to separate the different fractions, and Nuclear Magnetic Resonance (NMR) spectroscopy to assess and quantify the aliphatic hydrogen part with respect to the aromatic part. To achieve a comprehensive understanding of the chemical composition of the materials, Proton Nuclear Magnetic Resonance (¹H-NMR) analysis was conducted in solution, using CCl₄ as solvent, on three different neat bitumens and on their asphaltene and maltene fractions. The combined application of TLC and ¹H-NMR spectroscopy enables the advanced characterization of bitumens supplied from different sources or obtained from different processes. This further allows addressing the use of specific modifications according to the bitumen final applications. Full article

(This article belongs to the Section Chemical and Molecular Sciences)

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18 pages, 2394 KiB

Open AccessArticle

A Parallel Approach for Frequent Subgraph Mining in a Single Large Graph Using Spark

by Fengcai Qiao^1,*,†

, Xin Zhang^1,†, Pei Li^1,†, Zhaoyun Ding^1,†, Shanshan Jia^2,† and Hui Wang^1,†

¹ College of Engineering System, National University of Defense Technology, Changsha 410073, Hunan, China

² Digital Media Center, Hunan Education Publishing House, Changsha 410073, Hunan, China

^† Current address: No.109, Deya Road, Changsha 410073, Hunan, China.

Appl. Sci. 2018, 8(2), 230; https://doi.org/10.3390/app8020230 - 2 Feb 2018

Cited by 33 | Viewed by 7051

Abstract

Frequent subgraph mining (FSM) plays an important role in graph mining, attracting a great deal of attention in many areas, such as bioinformatics, web data mining and social networks. In this paper, we propose SSiGraM (Spark based Single Graph [...] Read more.

Frequent subgraph mining (FSM) plays an important role in graph mining, attracting a great deal of attention in many areas, such as bioinformatics, web data mining and social networks. In this paper, we propose SSiGraM (Spark based Single Graph Mining), a Spark based parallel frequent subgraph mining algorithm in a single large graph. Aiming to approach the two computational challenges of FSM, we conduct the subgraph extension and support evaluation parallel across all the distributed cluster worker nodes. In addition, we also employ a heuristic search strategy and three novel optimizations: load balancing, pre-search pruning and top-down pruning in the support evaluation process, which significantly improve the performance. Extensive experiments with four different real-world datasets demonstrate that the proposed algorithm outperforms the existing GraMi (Graph Mining) algorithm by an order of magnitude for all datasets and can work with a lower support threshold. Full article

(This article belongs to the Special Issue Socio-Cognitive and Affective Computing)

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15 pages, 1116 KiB

Open AccessArticle

Trajectory Tracking of an Omni-Directional Wheeled Mobile Robot Using a Model Predictive Control Strategy

by Chengcheng Wang^1,2,3, Xiaofeng Liu^1,2,3,*, Xianqiang Yang⁴, Fang Hu⁵, Aimin Jiang^1,2,3 and Chenguang Yang⁶

¹ College of IoT Engineering, Hohai University, Changzhou 213022, China

² Changzhou Key Laboratory of Robotics and Intelligent Technology, Hohai University, Changzhou 213022, China

³ Jiangsu Key Laboratory of Special Robots, Hohai University, Changzhou 213022, China

⁴ Research Institute of Intelligent Control and Systems, Harbin Institute of Technology, Harbin 150080, China

⁵ School of Electromechanical and Automobile Engineerng, Changzhou Vacational Institue of Engineering, Changzhou 213164, China

⁶ Key Laboratory of Autonomous Systems and Networked Control, College of Automation Science and Engineering, South China University of Technology, Guangzhou 510640, China

Appl. Sci. 2018, 8(2), 231; https://doi.org/10.3390/app8020231 - 2 Feb 2018

Cited by 136 | Viewed by 13921

Abstract

This paper addresses trajectory tracking of an omni-directional mobile robot (OMR) with three mecanum wheels and a fully symmetrical configuration. The omni-directional wheeled robot outperforms the non-holonomic wheeled robot due to its ability to rotate and translate independently and simultaneously. A kinematics model [...] Read more.

This paper addresses trajectory tracking of an omni-directional mobile robot (OMR) with three mecanum wheels and a fully symmetrical configuration. The omni-directional wheeled robot outperforms the non-holonomic wheeled robot due to its ability to rotate and translate independently and simultaneously. A kinematics model of the OMR is established and a model predictive control (MPC) algorithm with control and system constraints is designed to achieve point stabilization and trajectory tracking. Simulation results validate the accuracy of the established kinematics model and the effectiveness of the proposed MPC controller. Full article

(This article belongs to the Special Issue Bio-Inspired Robotics)

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10 pages, 4791 KiB

Open AccessArticle

Enhanced Harnessing of the Graviola Bioactive Components Using a Neoteric Sonication Cum Microwave Coadjuvant Extraction Protocol

by Se Chul Chun^1,†, Shang Xiaomin^1,†, Vimala Anthonydhason², Hyejin Jung¹, Shimels Tilahun Belachew³, Judy Gopal¹ and Diby Paul^4,*

¹ Department of Bioresource and Food Science, Konkuk University, Seoul 143-701, Korea

² Department of Biotechnology, IIT, Madras, Chennai 600 036, India

³ Food, Beverage and Pharmaceutical Industrial Development Institute, Ministry of Industry, Addis Abeba 1000, Ethiopia

⁴ Environmental Microbiology, Department of Environmental Engineering, Konkuk University, Seoul 143-701, Korea

^† Co-first authors—both authors have contributed equally in the manuscript.

Appl. Sci. 2018, 8(2), 232; https://doi.org/10.3390/app8020232 - 2 Feb 2018

Cited by 3 | Viewed by 6352

Abstract

Graviola is one of the most accomplished natural anticancer therapists gaining popularity in recent times. Harnessing the full benefit from tapping all of its rich bioactive reservoirs is absolutely worthy and mandatory. It is in this regard that a well optimized extraction methodology [...] Read more.

Graviola is one of the most accomplished natural anticancer therapists gaining popularity in recent times. Harnessing the full benefit from tapping all of its rich bioactive reservoirs is absolutely worthy and mandatory. It is in this regard that a well optimized extraction methodology gains paramount importance. In case of Graviola, no sophistication in terms of extraction methods is reported. A neoteric sonication cum microwave combined extraction technology was introduced that maximized the extraction process and minimized (7 min) the extraction time. The extraction efficiency was validated based on the significant enrichment of bioactive ingredients in Graviola extracts following the sonication cum microwave combined protocol. Full article

(This article belongs to the Collection Ultrasound in Extraction Processing)

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22 pages, 6757 KiB

Open AccessFeature PaperArticle

Object Tracking with LiDAR: Monitoring Taxiing and Landing Aircraft

by Zoltan Koppanyi^*

and Charles K. Toth

Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, 470 Hitchcock Hall, 2070 Neil Ave, Columbus, OH 43210, USA

Appl. Sci. 2018, 8(2), 234; https://doi.org/10.3390/app8020234 - 3 Feb 2018

Cited by 9 | Viewed by 5881

Abstract

Mobile light detection and ranging (LiDAR) sensors used in car navigation and robotics, such as the Velodyne’s VLP-16 and HDL-32E, allow for sensing the surroundings of the platform with high temporal resolution to detect obstacles, tracking objects and support path planning. This study [...] Read more.

Mobile light detection and ranging (LiDAR) sensors used in car navigation and robotics, such as the Velodyne’s VLP-16 and HDL-32E, allow for sensing the surroundings of the platform with high temporal resolution to detect obstacles, tracking objects and support path planning. This study investigates the feasibility of using LiDAR sensors for tracking taxiing or landing aircraft close to the ground to improve airport safety. A prototype system was developed and installed at an airfield to capture point clouds to monitor aircraft operations. One of the challenges of accurate object tracking using the Velodyne sensors is the relatively small vertical field of view (30°, 41.3°) and angular resolution (1.33°, 2°), resulting in a small number of points of the tracked object. The point density decreases with the object–sensor distance, and is already sparse at a moderate range of 30–40 m. The paper introduces our model-based tracking algorithms, including volume minimization and cube trajectories, to address the optimal estimation of object motion and tracking based on sparse point clouds. Using a network of sensors, multiple tests were conducted at an airport to assess the performance of the demonstration system and the algorithms developed. The investigation was focused on monitoring small aircraft moving on runways and taxiways, and the results indicate less than 0.7 m/s and 17 cm velocity and positioning accuracy achieved, respectively. Overall, based on our findings, this technology is promising not only for aircraft monitoring but for airport applications. Full article

(This article belongs to the Special Issue Laser Scanning)

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10 pages, 3031 KiB

Open AccessFeature PaperArticle

Large Scale Imaging by Fine Spatial Alignment of Multi-Scanning Data with Gel Cube Device

by Masaya Hagiwara^1,*

, Rina Nobata^1,2 and Tomohiro Kawahara³

¹ NanoSquare Research Institute, Osaka Prefecture University, Osaka 599-8570, Japan

² Department of Bioscience and Informatics, Osaka Prefecture University, Osaka 599-8570, Japan

³ Department of Biological Functions Engineering, Kyushu Institute of Technology, Kitakyushu 808-0196, Japan

Appl. Sci. 2018, 8(2), 235; https://doi.org/10.3390/app8020235 - 4 Feb 2018

Cited by 5 | Viewed by 5711

Abstract

In vitro three-dimensional (3D) culturing is considered essential in many biological fields. However, the imaging of developed 3D formations is often difficult, especially if the size of the sample is relatively large. The z-resolution of fluorescent imaging is low using low magnification [...] Read more.

In vitro three-dimensional (3D) culturing is considered essential in many biological fields. However, the imaging of developed 3D formations is often difficult, especially if the size of the sample is relatively large. The z-resolution of fluorescent imaging is low using low magnification lenses (4× and 10×) due to large focal depths. This paper describes 3D culture platform enabling large scale 3D imaging by fine spatial alignment of the image dataset obtained from multiple directions. A gel cube device was employed to conduct the multi-scanning and then a self-fluorescent microstructure in a cubic frame allows us spatially align image dataset within a few pixels. By synthesizing data from multiple scans, the platform enables us to visualize millimeter-sized 3D sample structure and individual cellular actin filaments at the same time. Millimeter depth imaging of a developed bronchial tree was achieved with high z-resolution. The device, which is applicable to most microscopy systems, can enhance the image quality without modifying current systems. Full article

(This article belongs to the Special Issue Microfluidics in Biology and Medicine)

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12 pages, 2617 KiB

Open AccessArticle

Repeater Insertion for Multi-Walled Carbon Nanotube Interconnects

by Peng-Wei Liu¹, Zi-Han Cheng¹, Wen-Sheng Zhao^1,*

, Qijun Lu², Zhangming Zhu² and Gaofeng Wang^1,*

¹ Key Lab of RF Circuits and Systems of Ministry of Education, School of Electronics and Information, Hangzhou Dianzi University, Hangzhou 310018, China

² School of Microelectronics, Xidian University, Xi’an 710071, China

Appl. Sci. 2018, 8(2), 236; https://doi.org/10.3390/app8020236 - 4 Feb 2018

Cited by 9 | Viewed by 4219

Abstract

Closed-form expressions for the optimized number and size of repeaters in multi-walled carbon nanotube (MWCNT) interconnects are presented. The contact resistance and inductive effects are taken into account. It is found that the propagation delay of MWCNT interconnects can be reduced effectively by [...] Read more.

Closed-form expressions for the optimized number and size of repeaters in multi-walled carbon nanotube (MWCNT) interconnects are presented. The contact resistance and inductive effects are taken into account. It is found that the propagation delay of MWCNT interconnects can be reduced effectively by inserting repeaters. However, the contact resistance has a significant influence on the optimized number and size of repeaters. Moreover, it is found that both the optimal number of repeaters and the minimum propagation delay are kept almost unchanged with the variation of carbon nanotube (CNT) kinetic inductance. The optimal number of repeaters in the MWCNT interconnect is much smaller than that in its Cu counterpart, thus saving chip area and power consumption. Full article

(This article belongs to the Special Issue Carbon Nanotubes for Interconnects)

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42 pages, 2308 KiB

Open AccessArticle

Optimal Selection of Clustering Algorithm via Multi-Criteria Decision Analysis (MCDA) for Load Profiling Applications

by Ioannis P. Panapakidis^1,* and Georgios C. Christoforidis²

¹ Department of Electrical Engineering, Technological Educational Institute of Thessaly, 41110 Larisa, Greece

² Department of Electrical Engineering, Western Macedonia University of Applied Sciences, 50100 Kozani, Greece

Appl. Sci. 2018, 8(2), 237; https://doi.org/10.3390/app8020237 - 4 Feb 2018

Cited by 30 | Viewed by 5194

Abstract

Due to high implementation rates of smart meter systems, considerable amount of research is placed in machine learning tools for data handling and information retrieval. A key tool in load data processing is clustering. In recent years, a number of researches have proposed [...] Read more.

Due to high implementation rates of smart meter systems, considerable amount of research is placed in machine learning tools for data handling and information retrieval. A key tool in load data processing is clustering. In recent years, a number of researches have proposed different clustering algorithms in the load profiling field. The present paper provides a methodology for addressing the aforementioned problem through Multi-Criteria Decision Analysis (MCDA) and namely, using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). A comparison of the algorithms is employed. Next, a single test case on the selection of an algorithm is examined. User specific weights are applied and based on these weight values, the optimal algorithm is drawn. Full article

(This article belongs to the Section Energy Science and Technology)

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30 pages, 1755 KiB

Open AccessArticle

Plasmonic Physics of 2D Crystalline Materials

by Zahra Torbatian¹ and Reza Asgari^1,2,*

¹ School of Nano Science, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran

² School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran

Appl. Sci. 2018, 8(2), 238; https://doi.org/10.3390/app8020238 - 4 Feb 2018

Cited by 30 | Viewed by 7565

Abstract

Collective modes of doped two-dimensional crystalline materials, namely graphene, MoS

_{2}

and phosphorene, both monolayer and bilayer structures, are explored using the density functional theory simulations together with the random phase approximation. The many-body dielectric functions of the materials are calculated using an [...] Read more.

Collective modes of doped two-dimensional crystalline materials, namely graphene, MoS

_{2}

and phosphorene, both monolayer and bilayer structures, are explored using the density functional theory simulations together with the random phase approximation. The many-body dielectric functions of the materials are calculated using an ab initio based model involving material-realistic physical properties. Having calculated the electron energy-loss, we calculate the collective modes of each material considering the in-phase and out-of-phase modes for bilayer structures. Furthermore, owing to many band structures and intreband transitions, we also find high-energy excitations in the systems. We explain that the material-specific dielectric function considering the polarizability of the crystalline material such as MoS

_{2}

are needed to obtain realistic plasmon dispersions. For each material studied here, we find different collective modes and describe their physical origins. Full article

(This article belongs to the Special Issue Plasmonics, Photonics and Optoelectronics on Two-Dimensional Materials)

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17 pages, 11044 KiB

Open AccessArticle

An Innovative and Efficient Method for Reverse Design of Wheel-Rail Profiles

by Rong Chen^1,2

, Chenyang Hu^1,2

, Jingmang Xu^1,2,*, Ping Wang^1,2, Jiayin Chen^1,2 and Yuan Gao^1,2

¹ Key Laboratory of High-Speed Railway Engineering, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China

² School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China

Appl. Sci. 2018, 8(2), 239; https://doi.org/10.3390/app8020239 - 5 Feb 2018

Cited by 7 | Viewed by 4543

Abstract

Well-designed wheel-rail profiles are not only helpful in achieving expected dynamic vehicle performance but also in extending the service lives of wheels and rails. In this paper, a method for designing wheel-rail profiles is presented based on the rolling radius difference. This method [...] Read more.

Well-designed wheel-rail profiles are not only helpful in achieving expected dynamic vehicle performance but also in extending the service lives of wheels and rails. In this paper, a method for designing wheel-rail profiles is presented based on the rolling radius difference. This method consists of three parts, i.e., the reverse designs of wheel profiles, symmetric rail profiles and non-symmetric rail profiles. A reverse design method for wheel-rail profiles that can obtain smooth profile formed by quadratic curves is established according to the mapping relation between the rolling radius difference and the wheel-rail profile gradient. This reverse design method is verified and an example for optimizing the design of wheel profiles is introduced. Results show that the design method is effective and efficient. The static/dynamic indexes of the optimized wheel profiles matched with CHN60 can be greatly improved. According to the comparative analysis of wheel-rail contact and dynamic performance, when the lateral displacement reaches 6 mm, the maximum contact stress will be distributed evenly and can be decreased by 184.4 MPa compared to that of existing profiles, while the critical speed can be increased by 10.8% and the running stability can be improved by around 7%. It can be seen that this method is useful for the design of new wheel-rail profiles and optimization of existing wheel-rail profiles. Full article

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18 pages, 5702 KiB

Open AccessFeature PaperArticle

Thermographic Non-Destructive Evaluation for Natural Fiber-Reinforced Composite Laminates

by Hai Zhang^1,*,†

, Stefano Sfarra^2,3

, Fabrizio Sarasini⁴

, Carlo Santulli⁵

, Henrique Fernandes⁶

, Nicolas P. Avdelidis^1,7, Clemente Ibarra-Castanedo¹

and Xavier P. V. Maldague¹

¹ Computer Vision and Systems Laboratory (CVSL), Department of Electrical and Computer Engineering, Laval University, 1065 av. de la Médecine, Quebec City, QC G1V 0A6, Canada

² Department of Industrial and Information Engineering and Economics, University of L’Aquila, 67100 L’Aquila, Italy

³ Tomsk Polytechnic University, 634028 Tomsk, Russia

⁴ Department of Chemical Engineering Materials Environment & UDR INSTM, Sapienza University of Rome, 00184 Rome, Italy

⁵ School of Architecture and Design (SAD), University of Camerino, 63100 Ascoli Piceno, Italy

⁶ School of Computer Sciences, Federal University of Uberlandia, Uberlandia 38400-902, Brazil

⁷ Aerospace Integration Research Centre (AIRC), College Road, Cranfield MK43 0AL, UK

^† Current Address: Center for Advanced Diffusion-Wave Technologies (CADIFT), Department of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, ON M5S 3G8, Canada.

Appl. Sci. 2018, 8(2), 240; https://doi.org/10.3390/app8020240 - 5 Feb 2018

Cited by 26 | Viewed by 5372

Abstract

Natural fibers, including mineral and plant fibers, are increasingly used for polymer composite materials due to their low environmental impact. In this paper, thermographic non-destructive inspection techniques were used to evaluate and characterize basalt, jute/hemp and bagasse fibers composite panels. Different defects were [...] Read more.

Natural fibers, including mineral and plant fibers, are increasingly used for polymer composite materials due to their low environmental impact. In this paper, thermographic non-destructive inspection techniques were used to evaluate and characterize basalt, jute/hemp and bagasse fibers composite panels. Different defects were analyzed in terms of impact damage, delaminations and resin abnormalities. Of particular interest, homogeneous particleboards of sugarcane bagasse, a new plant fiber material, were studied. Pulsed phase thermography and principal component thermography were used as the post-processing methods. In addition, ultrasonic C-scan and continuous wave terahertz imaging were also carried out on the mineral fiber laminates for comparative purposes. Finally, an analytical comparison of different methods was given. Full article

(This article belongs to the Special Issue Novel Ideas for Infrared Thermography also Applied in Integrated Approaches)

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18 pages, 3688 KiB

Open AccessArticle

Robotic Motion Learning Framework to Promote Social Engagement

by Rachael Burns¹, Myounghoon Jeon² and Chung Hyuk Park^1,*

¹ Department of Biomedical Engineering, The George Washington University, Washington, DC 20052, USA

² Department of Cognitive and Learning Sciences, Department of Computer Science, Michigan Technological University, Houghton, MI 49931, USA

Appl. Sci. 2018, 8(2), 241; https://doi.org/10.3390/app8020241 - 5 Feb 2018

Cited by 9 | Viewed by 8354

Abstract

Imitation is a powerful component of communication between people, and it poses an important implication in improving the quality of interaction in the field of human–robot interaction (HRI). This paper discusses a novel framework designed to improve human–robot interaction through robotic imitation of [...] Read more.

Imitation is a powerful component of communication between people, and it poses an important implication in improving the quality of interaction in the field of human–robot interaction (HRI). This paper discusses a novel framework designed to improve human–robot interaction through robotic imitation of a participant’s gestures. In our experiment, a humanoid robotic agent socializes with and plays games with a participant. For the experimental group, the robot additionally imitates one of the participant’s novel gestures during a play session. We hypothesize that the robot’s use of imitation will increase the participant’s openness towards engaging with the robot. Experimental results from a user study of 12 subjects show that post-imitation, experimental subjects displayed a more positive emotional state, had higher instances of mood contagion towards the robot, and interpreted the robot to have a higher level of autonomy than their control group counterparts did. These results point to an increased participant interest in engagement fueled by personalized imitation during interaction. Full article

(This article belongs to the Special Issue Social Robotics)

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13 pages, 3961 KiB

Open AccessArticle

Interpolating Spline Curve-Based Perceptual Encryption for 3D Printing Models

by Giao N. Pham¹

, Suk-Hwan Lee² and Ki-Ryong Kwon^1,*

¹ Department of IT Convergence & Application Engineering, Pukyong National University, Busan 608-737, Korea

² Department of Information Security, Tongmyong University, Busan 608-711, Korea

Appl. Sci. 2018, 8(2), 242; https://doi.org/10.3390/app8020242 - 5 Feb 2018

Cited by 8 | Viewed by 5522

Abstract

With the development of 3D printing technology, 3D printing has recently been applied to many areas of life including healthcare and the automotive industry. Due to the benefit of 3D printing, 3D printing models are often attacked by hackers and distributed without agreement [...] Read more.

With the development of 3D printing technology, 3D printing has recently been applied to many areas of life including healthcare and the automotive industry. Due to the benefit of 3D printing, 3D printing models are often attacked by hackers and distributed without agreement from the original providers. Furthermore, certain special models and anti-weapon models in 3D printing must be protected against unauthorized users. Therefore, in order to prevent attacks and illegal copying and to ensure that all access is authorized, 3D printing models should be encrypted before being transmitted and stored. A novel perceptual encryption algorithm for 3D printing models for secure storage and transmission is presented in this paper. A facet of 3D printing model is extracted to interpolate a spline curve of degree 2 in three-dimensional space that is determined by three control points, the curvature coefficients of degree 2, and an interpolating vector. Three control points, the curvature coefficients, and interpolating vector of the spline curve of degree 2 are encrypted by a secret key. The encrypted features of the spline curve are then used to obtain the encrypted 3D printing model by inverse interpolation and geometric distortion. The results of experiments and evaluations prove that the entire 3D triangle model is altered and deformed after the perceptual encryption process. The proposed algorithm is responsive to the various formats of 3D printing models. The results of the perceptual encryption process is superior to those of previous methods. The proposed algorithm also provides a better method and more security than previous methods. Full article

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15 pages, 5868 KiB

Open AccessArticle

Identification of Operating Parameters Most Strongly Influencing the Jetting Performance in a Piezoelectric Actuator-Driven Dispenser

by Jung Woo Sohn¹ and Seung-Bok Choi^2,*

¹ Department of Mechanical Design Engineering, Kumoh National Institute of Technology, Gumi, Gyeongbuk 39177, Korea

² Department of Mechanical Engineering, Inha University, Incheon 22212, Korea

Appl. Sci. 2018, 8(2), 243; https://doi.org/10.3390/app8020243 - 5 Feb 2018

Cited by 13 | Viewed by 4817

Abstract

This work identifies crucial operating parameters which most significantly influence the jetting performances of piezostack-driven non-contact dispensers. This is achieved through experimental investigation and statistical analysis. After introducing the configuration and operating principle of the piezoelectric jetting dispenser, an experimental setup is constructed [...] Read more.

This work identifies crucial operating parameters which most significantly influence the jetting performances of piezostack-driven non-contact dispensers. This is achieved through experimental investigation and statistical analysis. After introducing the configuration and operating principle of the piezoelectric jetting dispenser, an experimental setup is constructed in order to test the jetting performance, such as the dispensed amount. After selecting four significant operating parameters for the light-emitting diode (LED)-packaging process, two levels for each parameter are considered. Subsequently, the weight of a single dispensed dot is measured 100 times, and the average weight and standard deviation are calculated for each experimental set. The results are then statistically analyzed using a commercial software package. Finally, the crucial operating parameters which provide a low average weight and a minimum variation in the weight of a single dispensed dot are identified. Full article

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13 pages, 2081 KiB

Open AccessArticle

Study on Lubrication Performance of Journal Bearing with Multiple Texture Distributions

by Jun Wang^1,2, Junhong Zhang^1,2, Jiewei Lin^1,* and Liang Ma^1,3,*

¹ State Key Laboratory of Engine, Tianjin University, Tianjin 300072, China

² Renai College, Tianjin University, Tianjin 301636, China

³ College of Aeronautical Engineering, Civil Aviation University of China, Tianjin 300300, China

Appl. Sci. 2018, 8(2), 244; https://doi.org/10.3390/app8020244 - 6 Feb 2018

Cited by 25 | Viewed by 5471

Abstract

The lubrication performance of journal bearings with different sorts of uniformly distributed micro-spherical textures are studied in this paper. Geometries and dynamic models of journal bearings with pure concave/convex textures are developed. The validity of the proposed models is verified against the oil [...] Read more.

The lubrication performance of journal bearings with different sorts of uniformly distributed micro-spherical textures are studied in this paper. Geometries and dynamic models of journal bearings with pure concave/convex textures are developed. The validity of the proposed models is verified against the oil film pressure distribution from the literature. The effects of geometry parameters (the texture depth and the area density) on the load capacity and the friction coefficient of the bearing are analyzed and discussed. Results indicate that: the bearing load capacity is reduced by the concave spherical texture, but enhanced by the convex texture; both the concave and convex textures have a very slight influence on the friction coefficient. Aiming to further improve the bearing lubrication performance, a novel concave-convex composite texture is proposed and modelled. Results show that the composite texture can significantly improve both the load capacity and the friction coefficient, because the concave spherical segments among the convex ones protect the oil film from rupture near the main load region. The oil film region is expanded by the composite texture as well. Full article

(This article belongs to the Section Mechanical Engineering)

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9 pages, 4239 KiB

Open AccessFeature PaperArticle

Stepwise Luneburg Lens for Bloch Surface Waves

by Myun-Sik Kim^*

, Babak Vosoughi Lahijani and Hans Peter Herzig

Optics & Photonics Technology Laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), Neuchâtel CH-2000, Switzerland

Appl. Sci. 2018, 8(2), 245; https://doi.org/10.3390/app8020245 - 6 Feb 2018

Cited by 5 | Viewed by 5067

Abstract

In order to enlarge the capability for in-plane manipulation of the Bloch surface wave (BSW), we investigate 2D gradient index (GRIN) optical components using a finite-difference time-domain (FDTD) numerical method. To ease difficulties in fabrication to acquire a continuous index profile of GRIN [...] Read more.

In order to enlarge the capability for in-plane manipulation of the Bloch surface wave (BSW), we investigate 2D gradient index (GRIN) optical components using a finite-difference time-domain (FDTD) numerical method. To ease difficulties in fabrication to acquire a continuous index profile of GRIN optical components, we propose a stepwise index profile. For 2D surface wave devices, such discrete index steps can be achieved by stepwise structuring of the top layer, also called the device layer. For the demonstration of the stepwise GRIN optics concept, we consider a Luneburg lens, which is a good example of the GRIN optical component that produces a strong focal spot on the shadow-side curvature of the lens. The limited index contrast of the BSW systems loosens the confinement of the focal spot. A mitigation plan is to elongate the circular geometry to the prolate ellipse. BSW-based Luneburg lenses with a relatively small number of steps and an elliptical geometry are demonstrated with comparable performances to a standard Luneburg lens. Full article

(This article belongs to the Special Issue Surface Waves on Planar Photonic Crystals)

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15 pages, 7530 KiB

Open AccessArticle

FE-Study on the Effect of Gradient Concrete on Early Constraint and Crack Risk

by Emanuel Strieder^1,*

, Raimund Hilber², Elisabeth Stierschneider¹ and Konrad Bergmeister¹

¹ Institute of Structural Engineering; Department of Civil Engineering and Natural Hazards, University of Natural Resources and Life Sciences (BOKU), 1190 Wien, Austria

² Ingwien.at Engineering Gmbh, 1010 Wien, Austria

Appl. Sci. 2018, 8(2), 246; https://doi.org/10.3390/app8020246 - 6 Feb 2018

Cited by 19 | Viewed by 5281

Abstract

In long-lasting mass concrete structures the desired material properties of the concrete mix to realize a durable concrete and a concrete surface without cracks conflict with each other. The requirement of concrete with high durability leads to high thermal energy release and therefore, [...] Read more.

In long-lasting mass concrete structures the desired material properties of the concrete mix to realize a durable concrete and a concrete surface without cracks conflict with each other. The requirement of concrete with high durability leads to high thermal energy release and therefore, as another consequence, to high crack risk. Crack reduction is achieved by use of concrete with low hydration energy, which on the other hand leads to a decrease in concrete durability. Besides from optimized base materials and concrete technology, a gradient material distribution in the cross-section could reduce the problem since durable concrete is needed near the surface and the requirement of low-hydration energy is located in the center of the member. A simplified model is used to investigate the possible effect of a gradient concrete material distribution in mass concrete structures on crack reduction. The results of the analysis show that gradient concrete might contribute to lowering the constraint stresses and therefore the crack risk during concrete hardening. Full article

(This article belongs to the Special Issue Modelling of Early Age Cracking Risks and Serviceability of Concrete Structures)

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17 pages, 6884 KiB

Open AccessArticle

Conversion of a Direct to an Indirect Refrigeration System at Medium Temperature Using R-134a and R-507A: An Energy Impact Analysis

by Rodrigo Llopis^*

, Daniel Sánchez

, Ramón Cabello

, Jesús Catalán-Gil

and Laura Nebot-Andrés

Department of Mechanical Engineering and Construction, Campus del Riu Sec. s/n, Jaume I University, E-12071 Castellón, Spain

Appl. Sci. 2018, 8(2), 247; https://doi.org/10.3390/app8020247 - 6 Feb 2018

Cited by 10 | Viewed by 7309

Abstract

This work presents the experimental evaluation of energy consumption and refrigerant charge reduction when a commercial direct expansion refrigeration system is converted into an indirect system. The evaluation (with R-134a and R-507A) used a commercial cabinet with doors for medium temperature and a [...] Read more.

This work presents the experimental evaluation of energy consumption and refrigerant charge reduction when a commercial direct expansion refrigeration system is converted into an indirect system. The evaluation (with R-134a and R-507A) used a commercial cabinet with doors for medium temperature and a single-stage refrigeration cycle using a semi-hermetic compressor and electronic expansion valve; 24-h energy consumption tests were performed at laboratory conditions for each refrigerant and configuration at three heat rejection levels (23.3, 32.8 and 43.6 °C), maintaining an average product temperature inside the cabinet of 2 °C. The work analyses the impact of the conversion on temperature and pressure indicators, as well as, in the energy performance of each element. For R-134a the refrigerant charge was reduced in a 42.9%, but the energy consumption rose by 22.0%–22.8%; for R-507A the charge reduction was of 32.8% with an increase in energy consumption of between 27.7% and 38.7%. Full article

(This article belongs to the Special Issue Sciences in Heat Pump and Refrigeration)

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9 pages, 949 KiB

Open AccessArticle

Photonic Crystal-Supported Long-Range Surface Plasmon-Polaritons Propagating Along High-Quality Silver Nanofilms

by Sergey K. Sekatskii^1,*, Anton Smirnov¹, Giovanni Dietler¹, Mohammad Nur E. Alam²

, Mikhail Vasiliev²

and Kamal Alameh²

¹ Laboratoire de Physique de la Matière Vivante, IPHYS, Ecole Polytechnique Fédérale de Lausanne, BSP, CH 1015 Lausanne, Switzerland

² Electron Science Research Institute, Edith Cowan University, 270 Joondalup Dr., Joondaloop WA 6027, Australia

Appl. Sci. 2018, 8(2), 248; https://doi.org/10.3390/app8020248 - 6 Feb 2018

Cited by 7 | Viewed by 4813

Abstract

Long-range surface plasmon-polaritons (LRSPP) with a propagation length equal to 180 microns at the wavelength of 633 nm have been observed at the interface of 12.5 nm-thick silver nanofilm, coated by a 20 nm-thick protective ZnS layer, with air. Their propagation has been [...] Read more.

Long-range surface plasmon-polaritons (LRSPP) with a propagation length equal to 180 microns at the wavelength of 633 nm have been observed at the interface of 12.5 nm-thick silver nanofilm, coated by a 20 nm-thick protective ZnS layer, with air. Their propagation has been supported by a specially prepared 40-layer 1D Photonic Crystal designed in such a manner that silver layer has been deposited directly onto thin ZnS layer, earlier shown to be a non-oxide material most suitable for the preparation of high-quality thin silver nanofilms. Full article

(This article belongs to the Special Issue Surface Waves on Planar Photonic Crystals)

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17 pages, 7049 KiB

Open AccessArticle

Study on SPH Viscosity Term Formulations

by Xing Zheng^1,*, Qingwei Ma^1,2 and Songdong Shao^1,3

¹ College of Shipbuilding Engineering, Harbin Engineering University, Harbin 150001, China

² School of Mathematics, Computer Science and Engineering, City University of London, London EC1V 0HB, UK

³ State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China

Appl. Sci. 2018, 8(2), 249; https://doi.org/10.3390/app8020249 - 7 Feb 2018

Cited by 21 | Viewed by 6074

Abstract

For viscosity-dominated flows, the viscous effect plays a much more important role. Since the viscosity term in SPH-governing (Smoothed Particle Hydrodynamics) equations involves the discretization of a second-order derivative, its treatment could be much more challenging than that of a first-order derivative, such [...] Read more.

For viscosity-dominated flows, the viscous effect plays a much more important role. Since the viscosity term in SPH-governing (Smoothed Particle Hydrodynamics) equations involves the discretization of a second-order derivative, its treatment could be much more challenging than that of a first-order derivative, such as the pressure gradient. The present paper summarizes a series of improved methods for modeling the second-order viscosity force term. By using a benchmark patch test, the numerical accuracy and efficiency of different approaches are evaluated under both uniform and non-uniform particle configurations. Then these viscosity force models are used to compute a documented lid-driven cavity flow and its interaction with a cylinder, from which the most recommended viscosity term formulation has been identified. Full article

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12 pages, 3550 KiB

Open AccessArticle

Multivariate Analysis of Transient State Infrared Images in Production Line Quality Control Systems

by Cristina Cristalli¹ and Dariusz Grabowski^2,*

¹ Department of Research for Innovation, Loccioni Group, via Fiume 16, 60030 Angeli di Rosora, Italy

² Faculty of Electrical Engineering, Silesian University of Technology, ul. Akademicka 10, 44-100 Gliwice, Poland

Appl. Sci. 2018, 8(2), 250; https://doi.org/10.3390/app8020250 - 7 Feb 2018

Cited by 4 | Viewed by 4268

Abstract

Manufacturers would like to increase production volumes while preserving the high quality of their products. The long testing times can cause a bottleneck of production processes especially taking into account the observed tendency for testing all produced devices. The main aim of this [...] Read more.

Manufacturers would like to increase production volumes while preserving the high quality of their products. The long testing times can cause a bottleneck of production processes especially taking into account the observed tendency for testing all produced devices. The main aim of this work consists in the analysis of time changes of features extracted from thermal images using the multivariate approach. The paper shows that if the principal component analysis (PCA), belonging to multivariate methods, is applied for quality control based on infrared images, then the minimum testing times can be estimated. In order to draw the final conclusions regarding testing times and, what is also very important, which principal components should be selected for classification, a detailed temporal analysis for an exemplary production line has been carried out. The future impact of the results includes higher productivity and cost-effectiveness due to the determination of an optimal decision time in production line quality control systems using the proposed approach. Full article

(This article belongs to the Special Issue Novel Ideas for Infrared Thermography also Applied in Integrated Approaches)

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17 pages, 15392 KiB

Open AccessArticle

Application of the Hybrid Simulation Method for the Full-Scale Precast Reinforced Concrete Shear Wall Structure

by Zaixian Chen^1,*, Huanding Wang^1,2, Hao Wang³

, Hongbin Jiang², Xingji Zhu^1,* and Kun Wang⁴

¹ Department of Civil Engineering, Harbin Institute of Technology at Weihai, Weihai 264209, China

² Harbin Institute of Technology, School of Civil Engineering, Harbin 150090, China

³ Department of Civil Engineering, Southeast University, Nanjing 210096, China

⁴ College of Civil Science and Engineering, Yangzhou University, Yangzhou 225127, China

Appl. Sci. 2018, 8(2), 252; https://doi.org/10.3390/app8020252 - 8 Feb 2018

Cited by 13 | Viewed by 5105

Abstract

The hybrid simulation (HS) testing method combines physical test and numerical simulation, and provides a viable alternative to evaluate the structural seismic performance. Most studies focused on the accuracy, stability and reliability of the HS method in the small-scale tests. It is a [...] Read more.

The hybrid simulation (HS) testing method combines physical test and numerical simulation, and provides a viable alternative to evaluate the structural seismic performance. Most studies focused on the accuracy, stability and reliability of the HS method in the small-scale tests. It is a challenge to evaluate the seismic performance of a twelve-story pre-cast reinforced concrete shear-wall structure using this HS method which takes the full-scale bottom three-story structural model as the physical substructure and the elastic non-linear model as the numerical substructure. This paper employs an equivalent force control (EFC) method with implicit integration algorithm to deal with the numerical integration of the equation of motion (EOM) and the control of the loading device. Because of the arrangement of the test model, an elastic non-linear numerical model is used to simulate the numerical substructure. And non-subdivision strategy for the displacement inflection point of numerical substructure is used to easily realize the simulation of the numerical substructure and thus reduce the measured error. The parameters of the EFC method are calculated basing on analytical and numerical studies and used to the actual full-scale HS test. Finally, the accuracy and feasibility of the EFC-based HS method is verified experimentally through the substructure HS tests of the pre-cast reinforced concrete shear-wall structure model. And the testing results of the descending stage can be conveniently obtained from the EFC-based HS method. Full article

(This article belongs to the Special Issue Development and Application of Nonlinear Dissipative Device in Structural Vibration Control)

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15 pages, 1291 KiB

Open AccessArticle

Pitch Channel Control of a REMUS AUV with Input Saturation and Coupling Disturbances

by Nailong Wu^1,2, Chao Wu^1,2,*, Tong Ge^1,2, Deqing Yang^1,2 and Rui Yang³

¹ State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

² School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

³ College of Engineering, Ocean University of China, Qingdao 266100, China

Appl. Sci. 2018, 8(2), 253; https://doi.org/10.3390/app8020253 - 8 Feb 2018

Cited by 25 | Viewed by 6578

Abstract

The motion of an underwater vehicle is prone to be affected by time-varying model parameters and the actuator limitation in control practice. Adaptive control is an effective method to deal with the general system dynamic uncertainties and disturbances. However, the effect of disturbances [...] Read more.

The motion of an underwater vehicle is prone to be affected by time-varying model parameters and the actuator limitation in control practice. Adaptive control is an effective method to deal with the general system dynamic uncertainties and disturbances. However, the effect of disturbances control on transient dynamics is not prominent. In this paper, we redesign the

L_{1}

adaptive control architecture (L1AC) with anti-windup (AW) compensator to guarantee robust and fast adaption of the underwater vehicle with input saturation and coupling disturbances. To reduce the fluctuation of vehicle states, the Riccati-based AW compensator is utilized to compensate the output signal from L1AC controller via taking proper modification. The proposed method is applied to the pitch channel of REMUS vehicle’s six Degrees Of Freedom (DOF) model with strong nonlinearities and compared with L1AC baseline controller. Simulations show the effectiveness of the proposed control strategy compared to the original L1AC. Besides, the fluctuation in roll channel coupled with pitch channel is suppressed according to the performances of control tests. Full article

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24 pages, 4393 KiB

Open AccessArticle

Power Sharing and Voltage Vector Distribution Model of a Dual Inverter Open-End Winding Motor Drive System for Electric Vehicles

by Yi-Fan Jia

, Liang Chu, Nan Xu^*, Yu-Kuan Li, Di Zhao

and Xin Tang

State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130022, China

Appl. Sci. 2018, 8(2), 254; https://doi.org/10.3390/app8020254 - 8 Feb 2018

Cited by 13 | Viewed by 6309

Abstract

A drive system with an open-end winding permanent magnet synchronous motor (OW-PMSM) fed by a dual inverter and powered by two independent power sources is suitable for electric vehicles. By using an energy conversion device as primary power source and an energy storage [...] Read more.

A drive system with an open-end winding permanent magnet synchronous motor (OW-PMSM) fed by a dual inverter and powered by two independent power sources is suitable for electric vehicles. By using an energy conversion device as primary power source and an energy storage element as secondary power source, this configuration can not only lower the DC-bus voltage and extend the driving range, but also handle the power sharing between two power sources without a DC/DC (direct current to direct current) converter. Based on a drive system model with voltage vector distribution, this paper proposes a desired power sharing calculation method and three different voltage vector distribution methods. By their selection strategy the optimal voltage vector distribution method can be selected according to the operating conditions. On the basis of the integral synthesizing of the desired voltage vector, the proposed voltage vector distribution method can reduce the inverter switching frequency while making the primary power source follow its desired output power. Simulation results confirm the validity of the proposed methods, which improve the primary power source’s energy efficiency by regulating its output power and lessen inverter switching loss by reducing the switching frequency. This system also provides an approach to the energy management function of electric vehicles. Full article

(This article belongs to the Special Issue Plug-in Hybrid Electric Vehicle (PHEV))

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10 pages, 5279 KiB

Open AccessArticle

Immediate Settlement of Ring Footings Resting on Inhomogeneous Finite Stratum

by Joon Kyu Lee¹ and Sangseom Jeong^2,*

¹ Department of Civil Engineering, University of Seoul, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul 02504, Korea

² Department of Civil and Environmental Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea

Appl. Sci. 2018, 8(2), 255; https://doi.org/10.3390/app8020255 - 8 Feb 2018

Cited by 10 | Viewed by 5711

Abstract

This paper describes the immediate settlement of uniformly loaded rough ring footings with any stiffness on an inhomogeneous finite layer overlying a rough rigid base, which is not yet covered in the literature. Numerical solutions for a wide range of geometric and material [...] Read more.

This paper describes the immediate settlement of uniformly loaded rough ring footings with any stiffness on an inhomogeneous finite layer overlying a rough rigid base, which is not yet covered in the literature. Numerical solutions for a wide range of geometric and material combinations are obtained by finite element method. The effects of dimensionless parameters related to footing internal opening, compressibility, footing stiffness, finite layer thickness and soil inhomogeneity are examined. Based on the results, design charts are presented in the form of settlement influence factors that can be used to calculate the immediate settlements at the inner and outer points of ring footings. Full article

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15 pages, 3598 KiB

Open AccessArticle

Visible and Near-Infrared Hyperspectral Imaging for Cooking Loss Classification of Fresh Broiler Breast Fillets

by Hongzhe Jiang¹

, Wei Wang^1,*

, Hong Zhuang², Seungchul Yoon², Yufeng Li^3,*

and Yi Yang¹

¹ College of Engineering, China Agricultural University, Beijing 100083, China

² Quality & Safety Assessment Research Unit, U.S. National Poultry Research Center, USDA-ARS, 950 College Station Rd., Athens, GA 30605, USA

³ State Environmental Protection Engineering Center for Mercury Pollution Prevention and Control, and CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China

Appl. Sci. 2018, 8(2), 256; https://doi.org/10.3390/app8020256 - 9 Feb 2018

Cited by 7 | Viewed by 5069

Abstract

Cooking loss (CL) is a critical quality attribute directly relating to meat juiciness. The potential of the hyperspectral imaging (HSI) technique was investigated for non-invasively classifying and visualizing the CL of fresh broiler breast meat. Hyperspectral images of total 75 fresh broiler breast [...] Read more.

Cooking loss (CL) is a critical quality attribute directly relating to meat juiciness. The potential of the hyperspectral imaging (HSI) technique was investigated for non-invasively classifying and visualizing the CL of fresh broiler breast meat. Hyperspectral images of total 75 fresh broiler breast fillets were acquired by the system operating in the visible and near-infrared (VNIR, 400–1000 nm) range. Mean spectra were extracted from regions of interest (ROIs) determined by pure muscle tissue pixels. CL was firstly measured by calculating the weight loss in cooking, and then fillets were grouped into high-CL and low-CL according to the threshold of 20%. The classification methods partial least square-discriminant analysis (PLS-DA) and radial basis function-support vector machine (RBF-SVM) were applied, respectively, to determine the optimal spectral calibration strategy. Results showed that the PLS-DA model developed using the data, that is, first-order derivative (Der1) of VNIR full spectra, performed best with correct classification rates (CCRs) of 0.90 and 0.79 for the calibration and prediction sets, respectively. Furthermore, to simplify the optimal PLS-DA model and make it practical, effective wavelengths were individually selected using uninformative variable elimination (UVE) and competitive adaptive reweighted sampling (CARS). Through performance comparison, the CARS-PLS-DA combination was identified as the optimal method and the PLS-DA model built with 18 informative wavelengths selected by CARS resulted in good CCRs of 0.86 and 0.79. Finally, classification maps were created by predicting CL categories of each pixel in the VNIR hyperspectral images using the CARS-PLS-DA model, and the general CL categories of fillets were readily discernible. The overall results were encouraging and showed the promising potential of the VNIR HSI technique for classifying fresh broiler breast fillets into different CL categories. Full article

(This article belongs to the Special Issue Hyperspectral Chemical Imaging for Food Authentication)

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24 pages, 15392 KiB

Open AccessArticle

Induction Thermography for Surface Crack Detection and Depth Determination

by Beate Oswald-Tranta

Institute for Automation, University of Leoben, Leoben A-8700, Austria

Appl. Sci. 2018, 8(2), 257; https://doi.org/10.3390/app8020257 - 9 Feb 2018

Cited by 64 | Viewed by 8272

Abstract

In the last few years, induction thermography has been established as a non-destructive testing method for localizing surface cracks in metals. The sample to be inspected is heated with a short induced electrical current pulse, and the infrared camera records—during and after the [...] Read more.

In the last few years, induction thermography has been established as a non-destructive testing method for localizing surface cracks in metals. The sample to be inspected is heated with a short induced electrical current pulse, and the infrared camera records—during and after the heating pulse—the temperature distribution at the surface. Transforming the temporal temperature development for each pixel to phase information makes not only highly reliable detection of the cracks possible but also allows an estimation of its depth. Finite element simulations were carried out to investigate how the phase contrast depends on parameters such as excitation frequency, pulse duration, material parameters, crack depth, and inclination angle of the crack. From these results, generalized functions for the dependency of the phase difference on all these parameters were derived. These functions can be used as an excellent guideline as to how measurement parameters should be optimized for a given material to be able to detect cracks and estimate their depth. Several experiments on different samples were also carried out, and the results compared with the simulations showed very good agreement. Full article

(This article belongs to the Special Issue Novel Ideas for Infrared Thermography also Applied in Integrated Approaches)

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13 pages, 5821 KiB

Open AccessArticle

Effect of Stiff Hangers on the Longitudinal Structural Behavior of Tied-Arch Bridges

by Juan Manuel García-Guerrero^* and Juan José Jorquera-Lucerga

Civil Engineering Department, Universidad Politécnica de Cartagena (UPCT), 30203 Cartagena, Spain

Appl. Sci. 2018, 8(2), 258; https://doi.org/10.3390/app8020258 - 9 Feb 2018

Cited by 11 | Viewed by 6931

Abstract

In the design process of an arch bridge, the designer may decide to stiffen the hangers linking the arch and the deck, usually in order to reduce the internal forces or the deflections. In this paper, the effect of stiffened hangers on the [...] Read more.

In the design process of an arch bridge, the designer may decide to stiffen the hangers linking the arch and the deck, usually in order to reduce the internal forces or the deflections. In this paper, the effect of stiffened hangers on the longitudinal in-plane structural behavior of arch bridges is studied. Then, the effect of the stiffness of the hangers and the relevance of the arch–deck relative stiffness are shown. The paper also describes how stiff hangers with a hinge—either at the bottom or the top—combine very high structural efficiency and ease of execution. Once the advantages of stiff hangers are described and a possible drawback is highlighted. The problem may arise for stiffened hangers, as the bending moments near the ends of the deck might become more adverse for symmetrical load cases than for asymmetrical load distributions, as this usually occurs in arch bridges. To address this problem, this paper suggests a novel solution by designing a combination of fixed and pinned hangers, which can be as efficient as a configuration where all the hangers are fixed, while simultaneously reducing the bending moment at the end zones of the deck. Full article

(This article belongs to the Section Mechanical Engineering)

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22 pages, 1945 KiB

Open AccessArticle

Analysis of Steel Wire Rope Diagnostic Data Applying Multi-Criteria Methods

by Audrius Čereška¹, Edmundas Kazimieras Zavadskas^2,*

, Vytautas Bucinskas³

, Valentinas Podvezko⁴ and Ernestas Sutinys⁵

¹ Department of Mechanical and Material Engineering, Vilnius Gediminas Technical University, Basanaviciaus str. 28, Vilnius LT-03324, Lithuania

² Institute of Sustainable Construction, Vilnius Gediminas Technical University, Sauletekio al. 11, Vilnius LT-10223, Lithuania

³ Department of Mechatronics, Robotics and Digital Manufacturing, Vilnius Gediminas Technical University, Basanaviciaus str. 28, Vilnius LT-03324, Lithuania

⁴ Department of Mathematical Statistics, Vilnius Gediminas Technical University, Sauletekio al. 11, Vilnius LT-10223, Lithuania

⁵ Department of Mechatronics, Robotics and Digital Manufacturing, Vilnius Gediminas Technical University, Basanaviciaus str. 28, Vilnius LT-03324, Lithuania

Appl. Sci. 2018, 8(2), 260; https://doi.org/10.3390/app8020260 - 9 Feb 2018

Cited by 34 | Viewed by 8562

Abstract

Steel ropes are complex flexible structures used in many technical applications, such as elevators, cable cars, and funicular cabs. Due to the specific design and critical safety requirements, diagnostics of ropes remains an important issue. Broken wire number in the steel ropes is [...] Read more.

Steel ropes are complex flexible structures used in many technical applications, such as elevators, cable cars, and funicular cabs. Due to the specific design and critical safety requirements, diagnostics of ropes remains an important issue. Broken wire number in the steel ropes is limited by safety standards when they are used in the human lifting and carrying installations. There are some practical issues on loose wires—firstly, it shows end of lifetime of the entire rope, independently of wear, lubrication or wrong winding on the drums or through pulleys; and, secondly, it can stick in the tight pulley—support gaps and cause deterioration of rope structure up to birdcage formations. Normal rope operation should not generate broken wires, so increasing of their number shows a need for rope installation maintenance. This paper presents a methodology of steel rope diagnostics and the results of analysis using multi-criteria analysis methods. The experimental part of the research was performed using an original test bench to detect broken wires on the rope surface by its vibrations. Diagnostics was performed in the range of frequencies from 60 to 560 Hz with a pitch of 50 Hz. The obtained amplitudes of the broken rope wire vibrations, different from the entire rope surface vibration parameters, was the significant outcome. Later analysis of the obtained experimental results revealed the most significant values of the diagnostic parameters. The evaluation of the power of the diagnostics was implemented by using multi-criteria decision-making (MCDM) methods. Various decision-making methods are necessary due to unknown efficiencies with respect to the physical phenomena of the evaluated processes. The significance of the methods was evaluated using objective methods from the structure of the presented data. Some of these methods were proposed by authors of this paper. Implementation of MCDM in diagnostic data analysis and definition of the diagnostic parameters significance offers meaningful results. Full article

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21 pages, 2711 KiB

Open AccessFeature PaperArticle

Dissolved Oxygen Control in Activated Sludge Process Using a Neural Network-Based Adaptive PID Algorithm

by Xianjun Du^1,2,3,4, Junlu Wang^1,3,4, Veeriah Jegatheesan^2,* and Guohua Shi⁵

¹ College of Electrical and Information Engineering, Lanzhou University of Technology, Lanzhou 730050, China

² School of Engineering, Royal Melbourne Institute of Technology (RMIT) University, Melbourne 3000, Australia

³ Key Laboratory of Gansu Advanced Control for Industrial Processes, Lanzhou University of Technology, Lanzhou 730050, China

⁴ National Demonstration Center for Experimental Electrical and Control Engineering Education, Lanzhou University of Technology, Lanzhou 730050, China

⁵ Department of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China

Appl. Sci. 2018, 8(2), 261; https://doi.org/10.3390/app8020261 - 9 Feb 2018

Cited by 109 | Viewed by 13747

Abstract

The concentration of dissolved oxygen (DO) in the aeration tank(s) of an activated sludge system is one of the most important process control parameters. The DO concentration in the aeration tank(s) is maintained at a desired level by using a Proportional-Integral-Derivative (PID) controller. [...] Read more.

The concentration of dissolved oxygen (DO) in the aeration tank(s) of an activated sludge system is one of the most important process control parameters. The DO concentration in the aeration tank(s) is maintained at a desired level by using a Proportional-Integral-Derivative (PID) controller. Since the traditional PID parameter adjustment is not adaptive, the unknown disturbances make it difficult to adjust the DO concentration rapidly and precisely to maintain at a desired level. A Radial Basis Function (RBF) neural network (NN)-based adaptive PID (RBFNNPID) algorithm is proposed and simulated in this paper for better control of DO in an activated sludge process-based wastewater treatment. The powerful learning and adaptive ability of the RBF neural network makes the adaptive adjustment of the PID parameters to be realized. Hence, when the wastewater quality and quantity fluctuate, adjustments to some parameters online can be made by RBFNNPID algorithm to improve the performance of the controller. The RBFNNPID algorithm is based on the gradient descent method. Simulation results comparing the performance of traditional PID and RBFNNPID in maintaining the DO concentration show that the RBFNNPID control algorithm can achieve better control performances. The RBFNNPID control algorithm has good tracking, anti-disturbance and strong robustness performances. Full article

(This article belongs to the Special Issue Wastewater Treatment and Reuse Technologies)

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17 pages, 7126 KiB

Open AccessArticle

Aerodynamics and Motion Performance of the H-Type Floating Vertical Axis Wind Turbine

by Ying Guo, Liqin Liu, Xifeng Gao^* and Wanhai Xu

State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300072, China

Appl. Sci. 2018, 8(2), 262; https://doi.org/10.3390/app8020262 - 9 Feb 2018

Cited by 11 | Viewed by 7585

Abstract

Aerodynamics and motion performance of the floating vertical wind turbine (VAWT) were studied in this paper, where the wind turbine was H-type and the floating foundation was truss spar type. Based on the double-multiple-stream-tube theory, the formulae were deduced to calculate the aerodynamic [...] Read more.

Aerodynamics and motion performance of the floating vertical wind turbine (VAWT) were studied in this paper, where the wind turbine was H-type and the floating foundation was truss spar type. Based on the double-multiple-stream-tube theory, the formulae were deduced to calculate the aerodynamic loads acting on the wind turbine considering the motions of the floating foundation. The surge-heave-pitch nonlinear coupling equations of the H-type floating VAWT were established. Aerodynamics and motion performance of a 5 MW H-type floating VAWT was studied, and the effect of the floating foundation motions on the aerodynamic loads was analyzed. It is shown that the motions of the floating foundation on the aerodynamics cannot be ignored. The motion of the H-type floating VAWT was also compared with that of the Φ-type floating VAWT: they have the same floating foundation, rated output power, mooring system and total displacement. The results show that the H-type floating VAWT has better motion performance, and the mean values of surge, heave and pitch of the H-type floating VAWT are much smaller comparing with the Φ-type floating VAWT. Full article

(This article belongs to the Special Issue Wind Turbine Aerodynamics)

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15 pages, 4400 KiB

Open AccessArticle

HOVE-Wedge-Filtering of Geomorphologic Terrestrial Laser Scan Data

by Helmut Panholzer^1,* and Alexander Prokop²

¹ Department of Structural Engineering and Natural Hazards, BOKU, University of Natural Resources and Applied Life Sciences, Peter Jordan-Str. 82, Vienna 1190, Austria

² Department of Arctic Geology, University Centre in Svalbard (UNIS), P.O. Box 156 N-9171, Longyearbyen N-9171, Norway

Appl. Sci. 2018, 8(2), 263; https://doi.org/10.3390/app8020263 - 9 Feb 2018

Cited by 4 | Viewed by 5867

Abstract

Terrestrial laser scanning has become an important surveying technique in many fields such as natural hazard assessment. To analyse earth surface processes, it is useful to generate a digital terrain model originated from laser scan point cloud data. To determine the terrain surface [...] Read more.

Terrestrial laser scanning has become an important surveying technique in many fields such as natural hazard assessment. To analyse earth surface processes, it is useful to generate a digital terrain model originated from laser scan point cloud data. To determine the terrain surface as precisely as possible, it is often necessary to filter out points that do not represent the terrain surface. Examples are vegetation, vehicles, and animals. In mountainous terrain with a small-structured topography, filtering is very difficult. Here, automatic filtering solutions usually designed for airborne laser scan data often lead to unsatisfactory results. In this work, we further develop an existing approach for automated filtering of terrestrial laser scan data, which is based on the assumption that no other surface point can be located in the area above a direct line of sight between scanner and another measured point. By taking into account several environmental variables and a repetitive calculation method, the modified method leads to significantly better results. The root-mean-square-error (RSME) for the same test measurement area could be reduced from 5.284 to 1.610. In addition, a new approach for filtering and interpolation of terrestrial laser scanning data is presented using a grid with horizontal and vertical angular data and the measurement length. Full article

(This article belongs to the Special Issue Laser Scanning)

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18 pages, 3755 KiB

Open AccessFeature PaperArticle

A Comparison of Palladium Sorption Using Polyethylenimine Impregnated Alginate-Based and Carrageenan-Based Algal Beads

by Shengye Wang^1,*, Thierry Vincent¹, Catherine Faur² and Eric Guibal^1,*

¹ C2MA, IMT Mines Ales, University of Montpellier, 30100 Ales, France

² IEM, Institut Européen des Membranes, University of Montpellier, CNRS, ENSCM, 34090 Montpellier, France

Appl. Sci. 2018, 8(2), 264; https://doi.org/10.3390/app8020264 - 10 Feb 2018

Cited by 26 | Viewed by 6025

Abstract

Two kinds of algal beads were prepared using a carrageenan-based alga (Chrondrus crispus) and an alginate-based alga (Laminara digitata) ionotropically gelled with K(I) and Ca(II), respectively: the process consists of biopolymer partial extraction followed by hydrogel formation. The beads [...] Read more.

Two kinds of algal beads were prepared using a carrageenan-based alga (Chrondrus crispus) and an alginate-based alga (Laminara digitata) ionotropically gelled with K(I) and Ca(II), respectively: the process consists of biopolymer partial extraction followed by hydrogel formation. The beads were modified with branched polyethylenimine (bPEI) and glutaraldehyde (GA) using the impregnation method to improve their sorption capacity for Pd(II) in acid solution. SEM-EDX and FTIR techniques were used for characterizing the beads. The impacts of pH and presence of anions, cations, and Pt(IV) were studied in batch experiments. The beads were also applied for Pd(II) recovery from synthesized leaching liquors of a spent catalyst and a car catalytic converter via the sorption-desorption process. Results show that Pd is concentrated in the outer layer of L. digitata-bPEI-GA composite (LD/PEI) beads, while in the case of the C. crispus-bPEI-GA composite (CC/PEI), it is homogenously distributed in the whole mass of the sorbents. The difference is attributed to the repulsive force of the outer Ca(II)-alginate barrier of LD/PEI beads that makes it difficult for the branched polymer PEI to penetrate through the layer and be immobilized in the inner compartment. As a result, LD/PEI beads possess a lower maximum sorption capacity, but a slightly faster uptake at pH 1 than CC/PEI beads. In addition, CC/PEI beads present a better recovery performance compared to LD/PEI beads when applied for the treatment of synthesized leaching liquors. Full article

(This article belongs to the Special Issue Sustainable Environmental Remediation)

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18 pages, 1502 KiB

Open AccessArticle

Prioritization Assessment for Capability Gaps in Weapon System of Systems Based on the Conditional Evidential Network

by Dong Pei¹

, Daguo Qin¹, Yang Sun^2,*, Guangzhi Bu³ and Zhonghua Yao²

¹ Aerospace Command Academy, Space Engineering University, Beijing 101416, China

² Science and Technology on Complex Electronic System Simulation Laboratory, Space Engineering University, Beijing 101416, China

³ Complex System Simulation Lab, Beijing Institute of System Engineering, Beijing 100101, China

Appl. Sci. 2018, 8(2), 265; https://doi.org/10.3390/app8020265 - 11 Feb 2018

Cited by 6 | Viewed by 4217

Abstract

The prioritization of capability gaps for weapon system of systems is the basis for design and capability planning in the system of systems development process. In order to address input information uncertainties, the prioritization of capability gaps is computed in two steps using [...] Read more.

The prioritization of capability gaps for weapon system of systems is the basis for design and capability planning in the system of systems development process. In order to address input information uncertainties, the prioritization of capability gaps is computed in two steps using the conditional evidential network method. First, we evaluated the belief distribution of degree of required satisfaction for capabilities, and then calculated the reverse conditional belief function between capability hierarchies. We also provided verification for the feasibility and effectiveness of the proposed method through a prioritization of capability gaps calculation using an example of a spatial-navigation-and-positioning system of systems. Full article

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15 pages, 8141 KiB

Open AccessArticle

Investigation of Physical Phenomena and Cutting Efficiency for Laser Cutting on Anode for Li-Ion Batteries

by Dongkyoung Lee

Department of Mechanical and Automotive Engineering, Kongju National University, Cheonan 31080, Korea

Appl. Sci. 2018, 8(2), 266; https://doi.org/10.3390/app8020266 - 11 Feb 2018

Cited by 29 | Viewed by 6587

Abstract

Lithium-ion batteries have a higher energy density than other secondary batteries. Among the lithium-ion battery manufacturing process, electrode cutting is one of the most important processes since poor cut quality leads to performance degradation, separator protrusion, and local electric stress concentration. This may, [...] Read more.

Lithium-ion batteries have a higher energy density than other secondary batteries. Among the lithium-ion battery manufacturing process, electrode cutting is one of the most important processes since poor cut quality leads to performance degradation, separator protrusion, and local electric stress concentration. This may, eventually, lead to malfunction of lithium-ion batteries or explosion. The current mechanical cutting technology uses a contact process and this may lead to process instability. Furthermore, there are additional costs if the tools and cell design are changed. To solve these issues, laser cutting has been used. Conventional dependent parameters have limitations in investigating and explaining many physical phenomena during the laser cutting of electrodes. Therefore, this study proposes specific widths such as melting, top, and kerf width. Moreover, the relationship between laser parameters and multiphysical phenomena with the proposed widths are investigated. Five types of classification with regard to physical phenomena are presented and explained with SEM images. Cutting efficiency is estimated with the proposed widths. The proposed specific cutting widths, five types of geometrical classification, and cutting efficiency can be used as standardized parameters to evaluate the cutting quality. Full article

(This article belongs to the Special Issue Advanced Materials for Rechargeable Lithium Batteries)

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20 pages, 18777 KiB

Open AccessArticle

Driving Control of a Powered Wheelchair Considering Uncertainty of Gaze Input in an Unknown Environment

by Airi Ishizuka^1,*, Ayanori Yorozu² and Masaki Takahashi³

¹ School of Science for Open and Environmental Systems, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan

² Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan

³ Department of System Design Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan

Appl. Sci. 2018, 8(2), 267; https://doi.org/10.3390/app8020267 - 11 Feb 2018

Cited by 9 | Viewed by 3626

Abstract

This paper describes the motion control system for a powered wheelchair using eye gaze in an unknown environment. Recently, new Human-Computer Interfaces (HCIs) that have replaced joysticks have been developed for a person with a disability of the upper body. In this paper, [...] Read more.

This paper describes the motion control system for a powered wheelchair using eye gaze in an unknown environment. Recently, new Human-Computer Interfaces (HCIs) that have replaced joysticks have been developed for a person with a disability of the upper body. In this paper, movement of the eyes is used as an HCI. The wheelchair control system proposed in this study aims to achieve an operation such that a passenger gazes towards the direction he or she wants to move in the unknown environment. Implementation of such an operating method facilitates easy and accurate movement of the wheelchair even in complicated environments comprising passages on the same side. This paper presents a system based on gaze detection and environment recognition that are integrated by the fuzzy set theory in real time. In the fuzzy set theory, we achieve the movement to the passage which a passenger gazes towards among some passages by integrating the information of some passages and gaze. Moreover, we design it with consideration of uncertain gaze input by using the value of gaze detection accuracy. Moreover, we achieve obstacle avoidance by integrating the information of obstacles. This motion control system can support safe and smooth movement of the wheelchair by automatically calculating its direction of motion and velocity, to avoid obstacles and move in the gaze direction of the passenger. The effectiveness of the proposed system is demonstrated through experiments in a real environment. Full article

(This article belongs to the Section Mechanical Engineering)

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22 pages, 4921 KiB

Open AccessArticle

Energy-Based Design Criterion of Dissipative Bracing Systems for the Seismic Retrofit of Frame Structures

by Gloria Terenzi

Department of Civil and Environmental Engineering, University of Florence, 50139 Florence, Italy

Appl. Sci. 2018, 8(2), 268; https://doi.org/10.3390/app8020268 - 11 Feb 2018

Cited by 21 | Viewed by 4847

Abstract

Direct sizing criteria represent useful tools in the design of dissipative bracing systems for the advanced seismic protection of existing frame structures, especially when incorporated dampers feature a markedly non-linear behaviour. An energy-based procedure is proposed herein to this aim, focusing attention on [...] Read more.

Direct sizing criteria represent useful tools in the design of dissipative bracing systems for the advanced seismic protection of existing frame structures, especially when incorporated dampers feature a markedly non-linear behaviour. An energy-based procedure is proposed herein to this aim, focusing attention on systems including fluid viscous devices. The procedure starts by assuming prefixed reduction factors of the most critical response parameters in current conditions, which are evaluated by means of a conventional elastic finite element analysis. Simple formulas relating the reduction factors to the equivalent viscous damping ratio of the dampers, ξ_eq, are proposed. These formulas allow calculating the ξ_eq values that guarantee the achievement of the target factors. Finally, the energy dissipation capacity of the devices is deduced from ξ_eq, finalizing their sizing process. A detailed description of the procedure is presented in the article, by distinguishing the cases where the prevailing structural deficiencies are represented by poor strength of the constituting members, from the cases having excessive horizontal displacements. A demonstrative application to the retrofit design of a reinforced concrete gym building is then offered to explicate the steps of the sizing criterion in practice, as well as to evaluate the enhancement of the seismic response capacities generated by the installation of the dissipative system. Full article

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13 pages, 2676 KiB

Open AccessArticle

The Effects of Drying Temperature on Nitrogen Concentration Detection in Calcium Soil Studied by NIR Spectroscopy

by Pengcheng Nie^1,2,3, Tao Dong^1,2

, Yong He^1,2,*

, Shupei Xiao^1,2, Fangfang Qu^1,2 and Lie Lin^1,2

¹ College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China

² Key Laboratory of Sensors Sensing, Ministry of Agriculture, Zhejiang University, Hangzhou 310058, China

³ State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310058, China

Appl. Sci. 2018, 8(2), 269; https://doi.org/10.3390/app8020269 - 12 Feb 2018

Cited by 12 | Viewed by 3858

Abstract

Soil nitrogen is one of the crucial components for plant growth. An accurate diagnosis based on soil nitrogen information is the premise of scientific fertilization in precision agriculture. Soil nitrogen content acquisition based on near-infrared (NIR) spectroscopy shows the significant advantages of high [...] Read more.

Soil nitrogen is one of the crucial components for plant growth. An accurate diagnosis based on soil nitrogen information is the premise of scientific fertilization in precision agriculture. Soil nitrogen content acquisition based on near-infrared (NIR) spectroscopy shows the significant advantages of high accuracy, real-time analysis, and convenience. However, soil texture, soil moisture content, and drying temperature all affect soil nitrogen detection by NIR spectroscopy. In order to investigate the effects of drying temperature on calcium soil nitrogen detection and its characteristic bands, soil samples were detected at a 25 °C placement (ambient temperature) after 40 °C drying (medium temperature), 60 °C drying (medium-high temperature), 80 °C drying (high temperature), and 105 °C drying (extreme high temperature), respectively. Besides that, the original spectra were pretreated with five preprocessing methods, and the characteristic variables were selected by competitive adaptive reweighted squares (CARS) and backward interval partial least squares (BIPLS). The partial least squares (PLS) method was used for modeling and analysis. The predictive abilities were assessed using the coefficients of determination (R²), the root mean squared error (RMSE), and the residual predictive deviation (RPD). As a result, the characteristic bands focus on 928–960 nm and 1638–1680 nm when soil was detected after 40 °C, 60 °C, and 80 °C drying. Calcium soil obtained the best prediction accuracy

(R_{p}^{2} = 0.966, R M S E_{p} = 0.128 \frac{g}{kg}, R P D = 5.03)

after 40 °C drying by the method of CARS-BIPLS-PLS. Meanwhile, the prediction model also performed well when soil was detected after 60 °C drying

(R_{p}^{2} = 0.946, R M S E_{p} = 0.172 g / kg, R P D = 4.53)

and 80 °C drying

(R_{p}^{2} = 0.961, R M S E_{p} = 0.143 \frac{g}{kg}, R P D = 4.98)

. However, the calcium soil obtained the worst detection result when soil was placed at 25 °C. In conclusion, a low or extremely high drying temperature had an adverse influence on the soil nitrogen detection, and the 40 °C drying temperature as well as the CARS-BIPLS-PLS method were optimal to enhance the soil nitrogen detection accuracy. Full article

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11 pages, 1396 KiB

Open AccessArticle

Controlling Chemical Reactions in Confined Environments: Water Dissociation in MOF-74

by Erika M. A. Fuentes-Fernandez^1,†, Stephanie Jensen^2,†, Kui Tan¹, Sebastian Zuluaga², Hao Wang³, Jing Li³, Timo Thonhauser^2,4 and Yves J. Chabal^1,*

¹ Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080, USA

² Department of Physics and Center for Functional Materials, Wake Forest University, Winston-Salem, NC 27109, USA

³ Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA

⁴ Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA

^† These authors contributed equally to this work.

Appl. Sci. 2018, 8(2), 270; https://doi.org/10.3390/app8020270 - 12 Feb 2018

Cited by 12 | Viewed by 5615

Abstract

The confined porous environment of metal organic frameworks (MOFs) is an attractive system for studying reaction mechanisms. Compared to flat oxide surfaces, MOFs have the key advantage that they exhibit a well-defined structure and present significantly fewer challenges in experimental characterization. As an [...] Read more.

The confined porous environment of metal organic frameworks (MOFs) is an attractive system for studying reaction mechanisms. Compared to flat oxide surfaces, MOFs have the key advantage that they exhibit a well-defined structure and present significantly fewer challenges in experimental characterization. As an example of an important reaction, we study here the dissociation of water—which plays a critical role in biology, chemistry, and materials science—in MOFs and show how the knowledge of the structure in this confined environment allows for an unprecedented level of understanding and control. In particular, combining in-situ infrared spectroscopy and first-principles calculations, we show that the water dissociation reaction can be selectively controlled inside Zn-MOF-74 by alcohol, through both chemical and physical interactions. Methanol is observed to speed up water dissociation by 25% to 100%, depending on the alcohol partial pressure. On the other hand, co-adsorption of isopropanol reduces the speed of the water reaction, due mostly to steric interactions. In addition, we also investigate the stability of the product state after the water dissociation has occurred and find that the presence of additional water significantly stabilizes the dissociated state. Our results show that precise control of reactions within nano-porous materials is possible, opening the way for advances in fields ranging from catalysis to electrochemistry and sensors. Full article

(This article belongs to the Special Issue Nanoporous Materials and Their Applications)

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15 pages, 1573 KiB

Open AccessArticle

Topology Optimisation Using MPBILs and Multi-Grid Ground Element

by Suwin Sleesongsom^1,*

and Sujin Bureerat²

¹ Department of Aeronautical Engineering and Commercial Pilot, International Academy of Aviation Industry, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand

² Sustainable and Infrastructure Development Center, Department of Mechanical Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen City 40002, Thailand

Appl. Sci. 2018, 8(2), 271; https://doi.org/10.3390/app8020271 - 12 Feb 2018

Cited by 14 | Viewed by 4688

Abstract

This paper aims to study the comparative performance of original multi-objective population-based incremental learning (MPBIL) and three improvements of MPBIL. The first improvement of original MPBIL is an opposite-based concept, whereas the second and third method enhance the performance of MPBIL using the [...] Read more.

This paper aims to study the comparative performance of original multi-objective population-based incremental learning (MPBIL) and three improvements of MPBIL. The first improvement of original MPBIL is an opposite-based concept, whereas the second and third method enhance the performance of MPBIL using the multi and adaptive learning rate, respectively. Four classic multi-objective structural topology optimization problems are used for testing the performance. Furthermore, these topology optimization problems are improved by the method of multiple resolutions of ground elements, which is called a multi-grid approach (MG). Multi-objective design problems with MG design variables are then posed and tackled by the traditional MPBIL and its improved variants. The results show that using MPBIL with opposite-based concept and MG approach can outperform other MPBIL versions. Full article

(This article belongs to the Special Issue Soft Computing Techniques in Structural Engineering and Materials)

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17 pages, 12213 KiB

Open AccessArticle

An Improved MbICP Algorithm for Mobile Robot Pose Estimation

by Lin Li^1,2

, Jun Liu¹, Xinkai Zuo¹ and Haihong Zhu^1,*

¹ School of Resources and Environmental Science, Wuhan University, 129 Luoyu Road, Wuhan 430079, China

² Collaborative Innovation Center of Geo Spatial Technology, Wuhan University, 129 Luoyu Road, Wuhan 430079, China

Appl. Sci. 2018, 8(2), 272; https://doi.org/10.3390/app8020272 - 12 Feb 2018

Cited by 5 | Viewed by 4552

Abstract

This paper presents an improved version of the metric-based iterative closest point algorithm to estimate robot poses by matching 2D laser scans with different overlapping percentages. Because of the greatly varied density distribution of realistic point clouds, a resampling method is used to [...] Read more.

This paper presents an improved version of the metric-based iterative closest point algorithm to estimate robot poses by matching 2D laser scans with different overlapping percentages. Because of the greatly varied density distribution of realistic point clouds, a resampling method is used to accelerate the iteration process and protect the calculation of the rejection threshold from being distorted by reducing dense but unhelpful points. A new procedure that combines point-to-point and point-to-line metrics is used to determine the correct correspondence between partially overlapping scans, which maintains both efficiency and accuracy. In addition, a rejection threshold that is based on the MAD-from-median method is utilized to discard correspondences with large distances, which are likely to be incorrect. Experiments show that the improved algorithm is more accurate and robust than the standard algorithm with respect to the existence of non-overlapping areas, and testing demonstrates that it is valid in practice. Full article

(This article belongs to the Special Issue Laser Scanning)

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12 pages, 1528 KiB

Open AccessArticle

A Heuristic Method for the Reduction of the Outage Rate of High-Voltage Substations Due to Atmospheric Overvoltages

by Christos A. Christodoulou¹, Vasiliki Vita², Dionysios Voglitsis³, George Milushev⁴ and Lambros Ekonomou^2,*

¹ Department of Electrical and Computer Engineering, University of Thessaly, 382 21 Volos, Greece

² Department of Electrical and Electronic Engineering Educators ASPETE—School of Pedagogical and Technological Education, Ν. Ηeraklion, 141 21 Athens, Greece

³ Department of Electrical and Computer Engineering, Democritus University of Thrace, 671 00 Xanthi, Greece

⁴ Innovative Energy and Information Technologies LTD, j.k. Obelia 1, bl. 118, ent. A, app. 6, Sofia 1387, Bulgaria

Appl. Sci. 2018, 8(2), 273; https://doi.org/10.3390/app8020273 - 12 Feb 2018

Cited by 9 | Viewed by 5222

Abstract

The adequate protection against lightning surges and the limitation of the expected annual failure rate of high-voltage substations are critical issues, in an effort to secure the safety of the equipment and the personnel. Various factors affect the lightning performance of the substations, [...] Read more.

The adequate protection against lightning surges and the limitation of the expected annual failure rate of high-voltage substations are critical issues, in an effort to secure the safety of the equipment and the personnel. Various factors affect the lightning performance of the substations, determining the developed lightning surges and the expected outage rate, i.e., the grounding resistance, the length of the underground cable between the connected overhead transmission line and the power transformer, and the installation position of the arresters. In the current work, a heuristic method is developed to adjust different parameters of high-voltage substations that upgrade their lightning performance. The proposed methodology can be useful to the studies of substations’ designers and engineers, contributing effectively in the reduction or/and elimination of lightning failures. Full article

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18 pages, 254 KiB

Open AccessArticle

Towards New Mappings between Emotion Representation Models

by Agnieszka Landowska

Department of Software Engineering, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, 80-233 Gdansk, Poland

Appl. Sci. 2018, 8(2), 274; https://doi.org/10.3390/app8020274 - 12 Feb 2018

Cited by 20 | Viewed by 5461

Abstract

There are several models for representing emotions in affect-aware applications, and available emotion recognition solutions provide results using diverse emotion models. As multimodal fusion is beneficial in terms of both accuracy and reliability of emotion recognition, one of the challenges is mapping between [...] Read more.

There are several models for representing emotions in affect-aware applications, and available emotion recognition solutions provide results using diverse emotion models. As multimodal fusion is beneficial in terms of both accuracy and reliability of emotion recognition, one of the challenges is mapping between the models of affect representation. This paper addresses this issue by: proposing a procedure to elaborate new mappings, recommending a set of metrics for evaluation of the mapping accuracy, and delivering new mapping matrices for estimating the dimensions of a Pleasure-Arousal-Dominance model from Ekman’s six basic emotions. The results are based on an analysis using three datasets that were constructed based on affect-annotated lexicons. The new mappings were obtained with linear regression learning methods. The proposed mappings showed better results on the datasets in comparison with the state-of-the-art matrix. The procedure, as well as the proposed metrics, might be used, not only in evaluation of the mappings between representation models, but also in comparison of emotion recognition and annotation results. Moreover, the datasets are published along with the paper and new mappings might be created and evaluated using the proposed methods. The study results might be interesting for both researchers and developers, who aim to extend their software solutions with affect recognition techniques. Full article

(This article belongs to the Special Issue Socio-Cognitive and Affective Computing)

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18 pages, 2896 KiB

Open AccessArticle

Mathematical Models of Electro-Magnetohydrodynamic Multiphase Flows Synthesis with Nano-Sized Hafnium Particles

by Farooq Hussain^1,2, Rahmat Ellahi^1,3,*

and Ahmad Zeeshan¹

¹ Department of Mathematics & Statistics, International Islamic University, Islamabad 4400, Pakistan

² Department of Mathematics, Faculty of Arts and Basic Sciences, Balochistan University of Information Technology, Quetta 87300, Pakistan

³ Fulbright Fellow, Department of Mechanical Engineering, University of California, Riverside, CA 92521, USA

Appl. Sci. 2018, 8(2), 275; https://doi.org/10.3390/app8020275 - 12 Feb 2018

Cited by 79 | Viewed by 4629

Abstract

The multiphase fluid flow under the influence of electro-magnetohydrodynamics (EHD) is investigated in this study. The base fluid contains hafnium particles. Two illustrative models namely fluid phase and particulate phase are considered for three different geometries having great importance in both industrial and [...] Read more.

The multiphase fluid flow under the influence of electro-magnetohydrodynamics (EHD) is investigated in this study. The base fluid contains hafnium particles. Two illustrative models namely fluid phase and particulate phase are considered for three different geometries having great importance in both industrial and mechanical usage. The impact of pertinent parameters from different aspects is illustrated graphically with requisite discussion keeping in view their physical aspects. The stream lines are also erected to highlight their physical importance regarding the flow patterns. In addition, the paper is terminated by making a comparison with the existing literature as a limiting case of considered problem to confirm the validations of achieved results and hence found in excellent agreement. This model can be used to design and engineer for nozzle or diffuser type of injectors in the latest models of automobiles to improve their performance and reduce the consumption of fuel. Full article

(This article belongs to the Special Issue Nanofluids and Their Applications)

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19 pages, 3531 KiB

Open AccessArticle

Effective Biopotential Signal Acquisition: Comparison of Different Shielded Drive Technologies

by Yanbing Jiang^1,2, Oluwarotimi Williams Samuel^1,2, Xueyu Liu³, Xin Wang^1,2

, Paul Oluwagbenga Idowu^1,2, Peng Li⁴, Fei Chen⁵, Mingxing Zhu¹, Yanjuan Geng¹, Fengxia Wu⁶, Shixiong Chen^1,* and Guanglin Li^1,*

¹ CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China

² Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Shenzhen 518055, China

³ Institute of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing 400054, China

⁴ The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510630, China

⁵ Southern University of Science and Technology, Shenzhen 518055, China

⁶ Department of Anatomy, School of Medicine, Shandong University, Jinan 250100, China

Appl. Sci. 2018, 8(2), 276; https://doi.org/10.3390/app8020276 - 12 Feb 2018

Cited by 33 | Viewed by 14181

Abstract

Biopotential signals are mainly characterized by low amplitude and thus often distorted by extraneous interferences, such as power line interference in the recording environment and movement artifacts during the acquisition process. With the presence of such large-amplitude interferences, subsequent processing and analysis of [...] Read more.

Biopotential signals are mainly characterized by low amplitude and thus often distorted by extraneous interferences, such as power line interference in the recording environment and movement artifacts during the acquisition process. With the presence of such large-amplitude interferences, subsequent processing and analysis of the acquired signals becomes quite a challenging task that has been reported by many previous studies. A number of software-based filtering techniques have been proposed, with most of them being able to minimize the interferences but at the expense of distorting the useful components of the target signal. Therefore, this study proposes a hardware-based method that utilizes a shielded drive circuit to eliminate extraneous interferences on biopotential signal recordings, while also preserving all useful components of the target signal. The performance of the proposed method was evaluated by comparing the results with conventional hardware and software filtering methods in three different biopotential signal recording experiments (electrocardiogram (ECG), electro-oculogram (EOG), and electromyography (EMG)) on an ADS1299EEG-FE platform. The results showed that the proposed method could effectively suppress power line interference as well as its harmonic components, and it could also significantly eliminate the influence of unwanted electrode lead jitter interference. Findings from this study suggest that the proposed method may provide potential insight into high quality acquisition of different biopotential signals to greatly ease subsequent processing in various biomedical applications. Full article

(This article belongs to the Special Issue Bio-Inspired Robotics)

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20 pages, 1499 KiB

Open AccessArticle

Localized Space-Time Autoregressive Parameters Estimation for Traffic Flow Prediction in Urban Road Networks

by Jianbin Chen^1,2

, Demin Li^1,2,*, Guanglin Zhang^1,2

and Xiaolu Zhang^1,2

¹ College of Information Science & Technology, Donghua University, Shanghai 201620, China

² Engineering Research Center of Digitized Textile & Fashion Technology, Ministry of Education, Donghua University, Shanghai 201620, China

Appl. Sci. 2018, 8(2), 277; https://doi.org/10.3390/app8020277 - 12 Feb 2018

Cited by 16 | Viewed by 4535

Abstract

With the rapid increase of private vehicles, traffic congestion has become a worldwide problem. Various models have been proposed to undertake traffic prediction. Among them, autoregressive integrated moving average (ARIMA) models are quite popular for their good performance (simple, low complexity, etc.) in [...] Read more.

With the rapid increase of private vehicles, traffic congestion has become a worldwide problem. Various models have been proposed to undertake traffic prediction. Among them, autoregressive integrated moving average (ARIMA) models are quite popular for their good performance (simple, low complexity, etc.) in traffic prediction. Localized Space-Time ARIMA (LSTARIMA) improves ARIMA’s prediction accuracy by extending the widely used STARIMA with a dynamic weight matrix. In this paper, a localized space-time autoregressive (LSTAR) model was proposed and a new parameters estimation method was formulated based on the LSTARIMA model to reduce computational complexity for real-time prediction purposes. Moreover, two theorems are given and verified for parameter estimation of our proposed LSTAR model. The simulation results showed that LSTAR provided better prediction accuracy when compared to other time series models such as Shift, autoregressive (AR), seasonal moving average (Seasonal MA), and Space-Time AR (STAR). We found that the prediction accuracy of LSTAR was a bit lower than the LSTARIMA model in the simulation results. However, the computational complexity of the LSTAR model was also lower than the LSTARIMA model. Therefore, there exists a tradeoff between the prediction accuracy and the computational complexity for the two models. Full article

(This article belongs to the Special Issue Road Vehicles Surroundings Supervision: On-Board Sensors and Communications)

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22 pages, 2659 KiB

Open AccessArticle

Bio-Inspired Optimal Control Framework to Generate Walking Motions for the Humanoid Robot iCub Using Whole Body Models

by Yue Hu^1,2,*

and Katja Mombaur^1,2

¹ Optimization, Robotics & Biomechanics, Institute of Computer Engineering (ZITI), Heidelberg University, Berliner Str. 45, 69120 Heidelberg, Germany

² Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, INF205, 69120 Heidelberg, Germany

Appl. Sci. 2018, 8(2), 278; https://doi.org/10.3390/app8020278 - 12 Feb 2018

Cited by 17 | Viewed by 7335

Abstract

Bipedal locomotion remains one of the major open challenges of humanoid robotics. The common approaches are based on simple reduced model dynamics to generate walking trajectories, often neglecting the whole-body dynamics of the robots. As motions in nature are often considered as optimal [...] Read more.

Bipedal locomotion remains one of the major open challenges of humanoid robotics. The common approaches are based on simple reduced model dynamics to generate walking trajectories, often neglecting the whole-body dynamics of the robots. As motions in nature are often considered as optimal with respect to certain criteria, in this work, we present an optimal control-based approach that allows us to generate optimized walking motions using a precise whole-body dynamic model of the robot, in contrast with the common approaches. The optimal control problem is formulated to minimize a set of desired objective functions with respect to physical constraints of the robot and contact constraints of the walking phases; the problem is then solved with a direct multiple shooting method. We apply the formulation with combinations of different objective criteria to the model of a reduced version of the iCub humanoid robot of 15 internal DOF. The obtained trajectories are executed on the real robot, and we carry out a discussion on the differences between the outcomes of this approach with the classic approaches. Full article

(This article belongs to the Special Issue Bio-Inspired Robotics)

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18 pages, 2825 KiB

Open AccessArticle

Multiple-Factor Based Sparse Urban Travel Time Prediction

by Xinyan Zhu^1,2,3, Yaxin Fan¹, Faming Zhang^1,4,*, Xinyue Ye^5,*

, Chen Chen⁶ and Han Yue¹

¹ State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China

² Collaborative Innovation Center of Geospatial Technology, 129 Luoyu Road, Wuhan 430079, China

³ Key Lab of Aerospace Information Security and Trusted Computing of the Ministry of Education, Wuhan University, Wuhan 430079, China

⁴ Huawei Technologies Co., Ltd., Shenzhen 518129, China

⁵ Department of Geography, Kent State University, Kent, OH 44240, USA

⁶ School of Geodesy and Geomatics, Wuhan University, 129 Luoyu Road, Wuhan 430079, China

Appl. Sci. 2018, 8(2), 279; https://doi.org/10.3390/app8020279 - 12 Feb 2018

Cited by 13 | Viewed by 3802

Abstract

The prediction of travel time is challenging given the sparseness of real-time traffic data and the uncertainty of travel, because it is influenced by multiple factors on the congested urban road networks. In our paper, we propose a three-layer neural network from big [...] Read more.

The prediction of travel time is challenging given the sparseness of real-time traffic data and the uncertainty of travel, because it is influenced by multiple factors on the congested urban road networks. In our paper, we propose a three-layer neural network from big probe vehicles data incorporating multi-factors to estimate travel time. The procedure includes the following three steps. First, we aggregate data according to the travel time of a single taxi traveling a target link on working days as traffic flows display similar traffic patterns over a weekly cycle. We then extract feature relationships between target and adjacent links at 30 min interval. About 224,830,178 records are extracted from probe vehicles. Second, we design a three-layer artificial neural network model. The number of neurons in input layer is eight, and the number of neurons in output layer is one. Finally, the trained neural network model is used for link travel time prediction. Different factors are included to examine their influence on the link travel time. Our model is verified using historical data from probe vehicles collected from May to July 2014 in Wuhan, China. The results show that we could obtain the link travel time prediction results using the designed artificial neural network model and detect the influence of different factors on link travel time. Full article

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16 pages, 12269 KiB

Open AccessFeature PaperArticle

Formation and Characterization of Inkjet-Printed Nanosilver Lines on Plasma-Treated Glass Substrates

by Jae-Sung Kwon¹, Dong Jun Lee² and Je Hoon Oh^3,*

¹ Department of Mechanical Engineering, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, Korea

² Samsung Display, 181 Samsung-ro, Tangjeong-myeon, Asan, Chungcheongnam-do 31454, Korea

³ Department of Mechanical Engineering, Hanyang University, 55 Hanyangdaehak-ro, Sangrok-gu, Ansan, Gyeonggi-do 15588, Korea

Appl. Sci. 2018, 8(2), 280; https://doi.org/10.3390/app8020280 - 12 Feb 2018

Cited by 17 | Viewed by 6184

Abstract

In this study, we investigated geometrical characteristics of the inkjet-printed lines with non-zero receding contact angle (CA) on plasma-treated substrates in terms of various printing variables and analyzed the fluidic behavior and hydrodynamic instability involved in the line formation process. The printing variables [...] Read more.

In this study, we investigated geometrical characteristics of the inkjet-printed lines with non-zero receding contact angle (CA) on plasma-treated substrates in terms of various printing variables and analyzed the fluidic behavior and hydrodynamic instability involved in the line formation process. The printing variables included surface energy, droplet overlap ratio, printing frequency, a number of ink droplets, substrate temperature and printing procedures. For the study, a colloidal suspension containing 56 wt % silver nanoparticles in tetradecane solvent was used as a printing ink. It has electrical resistivity of 4.7 μΩ·cm. The substrates were obtained by performing a plasma enhanced chemical vapor deposition (PECVD) process with C₄F₈ and O₂ under various treatment conditions. As results of the experiments, the surface shape and pattern of the inkjet-printed Ag lines were dominantly influenced by the surface energy of the substrates, among the printing variables. Accordingly even when the receding CA was non-zero, bulging instability of the lines occurred forming separate circular patterns or regular bulges connected by ridges. It is a new finding of this study, which is completely different with the bulging instability of inkjet lines with zero receding CA specified by previous researches. The bulging instability decreased by increasing surface temperature of the substrates or employing interlacing procedure instead of continuous procedure for printing. The interlacing procedure also was advantageous to fabricate thick and narrow Ag lines with well-defined shape through overprinting on a hydrophobic substrate. These results will contribute greatly to not only the production of various printed electronics containing high-aspect-ratio structures but also the improvement of working performance of the devices. Full article

(This article belongs to the Special Issue Printed Electronics 2017)

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12 pages, 1922 KiB

Open AccessFeature PaperArticle

Bi-Functionalized Clay Nanotubes for Anti-Cancer Therapy

by William R. Grimes¹, Yangyang Luo¹

, Antwine W. McFarland, Jr.¹ and David K. Mills^2,3,*

¹ Molecular Sciences and Nanotechnology Program, Louisiana Tech University, Ruston, LA 71272, USA

² Center for Biomedical Engineering and Rehabilitation Science, Louisiana Tech University, Ruston, LA 71272, USA

³ School of Biological Sciences, Louisiana Tech University, Ruston, LA 71272, USA

Appl. Sci. 2018, 8(2), 281; https://doi.org/10.3390/app8020281 - 13 Feb 2018

Cited by 22 | Viewed by 6155

Abstract

Systemic toxicity is an undesired consequence of the majority of chemotherapeutic drugs. Multifunctional nanoparticles with combined diagnostic and therapeutic functions show great promise towards personalized nanomedicine. Halloysite clay nanotubes (HNTs) have shown potential as a drug delivery vehicle, and its surface can be [...] Read more.

Systemic toxicity is an undesired consequence of the majority of chemotherapeutic drugs. Multifunctional nanoparticles with combined diagnostic and therapeutic functions show great promise towards personalized nanomedicine. Halloysite clay nanotubes (HNTs) have shown potential as a drug delivery vehicle, and its surface can be modified and tailored as a targeted drug delivery system. In this short report, we modified the HNT surface by covalently bonding folic acid (FA) and fluorescein isothiocyanate (FITC). The modification of HNTs with folic acid imparts the potential to target tumor cells selectively. The addition of FITC offers a method for quantifying the effectiveness of the FA tagged HNTs ability to target tumor cells. We documented cell uptake of our bi-functionalized HNT (bHNT) through phase contrast and epi-fluorescent microscopy. bHNTs showed no signs of cytotoxicity up to a concentration of 150 µg/mL. The increase in cell death with increased bHNT concentration may be due to induced cytotoxicity resulting from intracellular bHNT accumulation that disrupts cellular function leading to cell death. With HNTs recognized as having the ability to serve as both a nanocontainer and nanocarrier, we envision our construct as a potential modular platform for potential use in cancer therapeutics. The HNT interior can be loaded with a variety of anti-cancer drugs (or other chemotherapeutics) and serve as a “death cargo” designed to kill cancer cells while providing feedback imaging data on drug efficacy. The surface of the HNT can be modified with gold or silver nanoparticles and used in photothermal therapy by converting light to heat inside tumors. Our HNT-based drug delivery system has the potential to provide localized and targeted therapies that limit or reduce side effects, reduce patient costs and length of hospital stays, and improve quality of life. However, further research is needed to validate the potential of this new chemotherapeutic drug delivery system. Full article

(This article belongs to the Special Issue Surface Modification of Halloysite Nanotubes)

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19 pages, 2389 KiB

Open AccessArticle

Multidimensional Analysis of the Effects of Waste Materials on Physical and Mechanical Properties of Recycled Mixtures with Foamed Bitumen

by Grzegorz Mazurek^*

and Marek Iwański

Department of Transportation Engineering, Faculty of Civil Engineering and Architecture, Kielce University of Technology, Al. Tysiąclecia Państwa Polskiego 7, 25-314 Kielce, Poland

Appl. Sci. 2018, 8(2), 282; https://doi.org/10.3390/app8020282 - 13 Feb 2018

Cited by 16 | Viewed by 3390

Abstract

The paper reports the results from the tests of recycled mixture samples containing waste materials. Six types of waste materials were used in the mineral mix, in various configurations. Statistical inference was based on the multidimensional analysis through the reduction of input data [...] Read more.

The paper reports the results from the tests of recycled mixture samples containing waste materials. Six types of waste materials were used in the mineral mix, in various configurations. Statistical inference was based on the multidimensional analysis through the reduction of input data size. Three groups of recycled mixtures were identified, each representing significantly different properties. The first group included rigid recycled mixtures, the second group comprised flexible mixtures, and those with the lowest cohesion and rigidity were in the third group. The statistical inference demonstrated that the recycled mixtures with waste materials to be most recommended were those with a high bitumen content (>2.5%). A high proportion of reclaimed asphalt pavement material was found to provide high performance of the recycled mixture, whereas recycled aggregate reduced the stiffness of the mix and its resistance to moisture. Full article

(This article belongs to the Section Materials Science and Engineering)

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16 pages, 3274 KiB

Open AccessArticle

Design of the First Italian Roundabout with Jointed Plain Concrete Pavement

by Paola Di Mascio¹

, Giuseppe Loprencipe¹

, Laura Moretti^1,*

, Maria Vittoria Corazza¹

, Sergio Vivaldi² and Giovanni Vincenti³

¹ Department of Civil, Constructional and Environmental Engineering, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy

² Colabeton S.p.A., Via della Vittorina 60, 06024 Gubbio, Italy

³ Colacem S.p.A., Via Corigliano d’Otranto, 73013 Galatina, Italy

Appl. Sci. 2018, 8(2), 283; https://doi.org/10.3390/app8020283 - 13 Feb 2018

Cited by 7 | Viewed by 5107

Abstract

This work presents the results of the overall design of the first Italian roundabout with jointed plain concrete pavement. The examined case study complies with current international standards and practices for geometry of roundabouts and road pavements. The construction of a concrete pavement [...] Read more.

This work presents the results of the overall design of the first Italian roundabout with jointed plain concrete pavement. The examined case study complies with current international standards and practices for geometry of roundabouts and road pavements. The construction of a concrete pavement in an urban roundabout will better manage and slow down fast vehicular flows, and increase traffic fluidity in an important junction, trafficked by heavy vehicles, where maintenance works should be reduced to avoid queues. The design of the roundabout involved several competences for: defining the geometry of the four-arm junction, designing the thickness of the jointed plain concrete pavement both on the circular crown and the arms, studying the mix design of a high resistance concrete. As regard to the pavement, the result of the study was an un-dowelled concrete pavement composed of square slabs laid on a cement concrete subbase and a granular layer. The shape of the slabs has been designed to optimize the structural performance of their material, which is a high strength concrete mix derived from an extensive laboratory test work. In general, the results summarized approaches typical of different design conditions: urban ones for traffic flow and safety needs; high-traffic ones for the chosen pavement type; airport ones for the absence of dowel and tie bars at the joints. Indeed, the article has highlighted that the design process of a concrete roundabout requires multiple analyses to consider various features and correctly re-design an existing urban junction. Its geometrical design, the structural design of the concrete pavement and the theoretical and experimental design of the concrete mix were the main phases of this process and they needed different competences to conduct comprehensive and appropriate analyses. Full article

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26 pages, 14769 KiB

Open AccessFeature PaperArticle

Multispectral Applications of Infrared Thermography in the Diagnosis and Protection of Built Cultural Heritage

by Antonia Moropoulou^*, Nicolas P. Avdelidis, Maria Karoglou, Ekaterini T. Delegou, Emmanouil Alexakis and Vasileios Keramidas

Zografou Campus, School of Chemical Engineering, National Technical University of Athens, 15780 Athens, Greece

Appl. Sci. 2018, 8(2), 284; https://doi.org/10.3390/app8020284 - 13 Feb 2018

Cited by 46 | Viewed by 6351

Abstract

Infrared thermography (IRT) is a powerful non contact imaging technique, appropriate for the protection of cultural heritage. The National Technical University of Athens research team (scientist responsible: A. Moropoulou), started to use this technique in the early 1990s, in all stages of a [...] Read more.

Infrared thermography (IRT) is a powerful non contact imaging technique, appropriate for the protection of cultural heritage. The National Technical University of Athens research team (scientist responsible: A. Moropoulou), started to use this technique in the early 1990s, in all stages of a conservation project, from decay diagnosis to assessment of conservation interventions and monitoring. The monuments investigated with the aid of this technique belonged to different historical periods, dating from antiquity to modern times. The main products of IRT, thermal maps of surfaces, were evaluated and exploited, based on the demands, special needs and requirements of each application. Additionally, in laboratory scale, many IRT measurements were performed in order to investigate the applicability and limitations of this technique for measuring a material’s thermophysical properties. All these data and accumulated knowledge and experience contributed to a set of recommendations, which enabled us to compile a protocol for the application of this technique in a more standardized way. Moreover, the added value of this practice permitted the successful application and integration of this technique in large-scale conservation projects, such as the Pythian Apollo Temple in Acropolis of Rhodes, during the diagnostic study phase, or at the Holy Aedicule, of the Holy Selphuchre in Jerusalem, during the rehabilitation works. Full article

(This article belongs to the Special Issue Novel Ideas for Infrared Thermography also Applied in Integrated Approaches)

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10 pages, 1416 KiB

Open AccessArticle

Validity of the Nintendo Wii Balance Board for Kinetic Gait Analysis

by Ryo Eguchi^1,*

and Masaki Takahashi²

¹ School of Science for Open and Environmental Systems, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan

² Department of System Design Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan

Appl. Sci. 2018, 8(2), 285; https://doi.org/10.3390/app8020285 - 14 Feb 2018

Cited by 14 | Viewed by 9051

Abstract

The Nintendo Wii Balance Board (WBB) has been suggested as an inexpensive, portable and accessible alternative to costly laboratory-grade force plates for measuring the vertical ground reaction force (vGRF) and center of pressure (COP). Kinetic gait analysis provides important information for the rehabilitation [...] Read more.

The Nintendo Wii Balance Board (WBB) has been suggested as an inexpensive, portable and accessible alternative to costly laboratory-grade force plates for measuring the vertical ground reaction force (vGRF) and center of pressure (COP). Kinetic gait analysis provides important information for the rehabilitation of patients with gait disorders; however, the validity of the WBB for measuring kinetic gait parameters has not been evaluated. Therefore, the purpose of this study is to determine the accuracy of walking force measurements—which change dynamically in a short period of stance time—collected with the WBB. Three healthy adults were asked to walk 10 steps along both straight and curved paths in clockwise (CW) and counterclockwise (CCW) directions while measurements were taken using the WBB and the force plate. The accuracy of the vGRF, COP trajectory, and stance duration were evaluated using the root-mean-square error (RMSE), Pearson’s correlation coefficient and Bland–Altman plots (BAPs) to compare the WBB and the force plate. The results of the vGRF showed high accuracy (r > 0.96 and %RMSE < 6.1% in the mean values), and the stance duration as defined by the vGRF and COP trajectory was equivalent to that of commercial instrumented insoles, which are used as an alternative to the force plates. From these results, we determined that the WBB may be used for kinetic gait analysis in clinical settings where lower accuracy is acceptable. Full article

(This article belongs to the Section Mechanical Engineering)

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15 pages, 7301 KiB

Open AccessArticle

Study of Standing-Wave Thermoacoustic Electricity Generators for Low-Power Applications

by Antonio Piccolo

Department of Engineering, University of Messina, Contrada di Dio, Sant’Agata, 98166 Messina, Italy

Appl. Sci. 2018, 8(2), 287; https://doi.org/10.3390/app8020287 - 14 Feb 2018

Cited by 8 | Viewed by 4574

Abstract

This paper is concerned with the study of low-cost, low-power thermoacoustic electricity generators. Based on target electrical output power values of 50 and 100 W, three standing wave prototypes (of both one-stage and two-stage prototypes) integrating a commercial loudspeaker with different coupling arrangements [...] Read more.

This paper is concerned with the study of low-cost, low-power thermoacoustic electricity generators. Based on target electrical output power values of 50 and 100 W, three standing wave prototypes (of both one-stage and two-stage prototypes) integrating a commercial loudspeaker with different coupling arrangements are conceived. Each stage consists of a square-pore stack sandwiched between hot and ambient heat exchangers. The working gas is air at atmospheric pressure. The prototypes’ efficiency in converting heat to electrical power is simulated by the specialized Design Environment for Low-Amplitude ThermoAcoustic Engines (DeltaEC) design tool based on the linear theory of thermoacoustics. At a given operation frequency, the optimal impedance matching between the loudspeaker and the engine is realized by adjusting both the engine parameters (stack location, stack length, heat exchangers length, loudspeaker location) and loudspeaker parameters (load resistance and box volume). Computations reveal that the one-stage engine and two-stage engine with loudspeakers coupled in side-branch mode are able to meet the target output power values with comparable thermal-to-electric efficiency (4.6%). The two-stage engine with the loudspeaker coupled in push–pull mode is unable to reach the desired power output and is characterized by low conversion efficiencies (2%) due to the poor loudspeaker–engine acoustic impedance matching. Full article

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26 pages, 16765 KiB

Open AccessArticle

Numerical Investigation into Effects of Viscous Flux Vectors on Hydrofoil Cavitation Flow and Its Radiated Flow Noise

by Sanghyeon Kim, Cheolung Cheong^*

and Warn-Gyu Park

School of Mechanical Engineering, Pusan National University, Busan 46241, Korea

Appl. Sci. 2018, 8(2), 289; https://doi.org/10.3390/app8020289 - 15 Feb 2018

Cited by 25 | Viewed by 5029

Abstract

In this study, cavitation flow around a hydrofoil and its radiated hydro-acoustic fields were numerically investigated, with an emphasis on the effects of viscous flux vectors. The full three-dimensional unsteady compressible Reynolds-averaged Navier–Stokes equations were numerically solved. The mass transfer model was adopted [...] Read more.

In this study, cavitation flow around a hydrofoil and its radiated hydro-acoustic fields were numerically investigated, with an emphasis on the effects of viscous flux vectors. The full three-dimensional unsteady compressible Reynolds-averaged Navier–Stokes equations were numerically solved. The mass transfer model was adopted to model phase changes between liquid water and vapor. To resolve the numerical instability problem arising from the rapid changes in local density and speed of sound of the mixture, the preconditioning and dual-time stepping methods were employed. The filter-based turbulent model was applied to resolve the unstable cavitation flow field more accurately. In splitting the viscous terms, three approaches for dealing with viscous flux vectors were considered: the so-called viscous lagging, full viscous, and thin-layer models. Radiated hydro-acoustic waves were predicted by applying the Ffowcs Williams and Hawkings equations. The effects of the viscous flux vectors on the predicted flow fields and its radiated noise were then examined by comparing the hydro-dynamic forces, velocity distribution, volume fraction, far-field sound directivities, and sound spectrum of the three approaches. The results revealed that the thin-layer model can provide predictions as accurate as the full viscous model, but required less computational time. Full article

(This article belongs to the Special Issue Underwater Acoustics, Communications and Information Processing)

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13 pages, 2562 KiB

Open AccessArticle

Seabed Sediment as an Annually Renewable Heat Source

by Anne Mäkiranta^1,*

, Birgitta Martinkauppi¹, Erkki Hiltunen¹ and Mauri Lieskoski²

¹ School of Technology and Innovations, University of Vaasa, P.O. Box 700, FI-65101 Vaasa, Finland

² Geo-Pipe GP Oy, Konsterinkuja 5, FI-65280 Vaasa, Finland

Appl. Sci. 2018, 8(2), 290; https://doi.org/10.3390/app8020290 - 15 Feb 2018

Cited by 4 | Viewed by 3519

Abstract

Thermal energy collected from the sediment layer under a water body has been suggested for use as a renewable heat source for a low energy network. A prototype system for using this sediment energy was installed in Suvilahti, Vaasa, in 2008 and is [...] Read more.

Thermal energy collected from the sediment layer under a water body has been suggested for use as a renewable heat source for a low energy network. A prototype system for using this sediment energy was installed in Suvilahti, Vaasa, in 2008 and is still in use. It provides a carbon-free heating and cooling solution as well as savings in energy costs for 42 houses. To be a real, renewable heat source, the thermal energy of the sediment layer needs to replenish annually. The goal of this paper is to verify the possible cooling or annual heat regeneration. The sediment temperatures were measured and analyzed in the years 2013–2015. The data were compared to the same period in 2008–2009. All measurements were taken in the same place. This paper also confirms the potential of the sediment heat, especially in the seabed sediment, using the temperature differences between the lowest and the highest values for the year. The results demonstrate that the collection of the heat energy does not cause permanent cooling of the sediment. This result was obtained by calculating the temperature difference between measurements in the warmest month and the month with the coldest temperatures. This indicates the extracted energy. The difference was found to be around 9.5 °C in 2008–2009, rising to around 11 °C for the years 2013–2014 and 2014–2015. This indicates the loaded energy. The energy utilization is sustainable: the sediment temperature has not permanently decreased despite the full use of the network for the heating and cooling of houses between 2008 and 2015. Full article

(This article belongs to the Special Issue New Heating and Cooling Concepts)

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20 pages, 6242 KiB

Open AccessArticle

Competitive Time Marching Solution Methods for Systems with Friction-Induced Nonlinearities

by Chiara Gastaldi^*

and Teresa M. Berruti

Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy

Appl. Sci. 2018, 8(2), 291; https://doi.org/10.3390/app8020291 - 15 Feb 2018

Cited by 19 | Viewed by 3936

Abstract

Finding efficient and accurate solution methods for nonlinear equilibrium equations is a challenging task. This is the case of systems with friction-induced nonlinearities, e.g., friction-damped turbomachinery assemblies and automotive applications such as brakes. In order to tackle this strategic task, several methods have [...] Read more.

Finding efficient and accurate solution methods for nonlinear equilibrium equations is a challenging task. This is the case of systems with friction-induced nonlinearities, e.g., friction-damped turbomachinery assemblies and automotive applications such as brakes. In order to tackle this strategic task, several methods have been developed, both in the time and in the frequency domains. Time marching methods are regarded as the most accurate option, but their computational cost becomes prohibitive when friction nonlinearities are present. This poses a problem in all those cases where alternative frequency domain methods cannot be applied effectively, e.g., if transients, non-periodic excitation/solution, or highly nonlinear systems are of interest. The purpose of this paper is to propose three independent methods to make time-marching more competitive. Two of these methods can be applied to any existing direct integration scheme with minimal adjustments, but the computational time cut they introduce is significant. The last method is instead tailored for systems where the inertia force contribution is negligible. All methods are thoroughly validated numerically using a standard Newmark-

β

integration scheme as a reference. Full article

(This article belongs to the Section Mechanical Engineering)

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15 pages, 7153 KiB

Open AccessArticle

Sodium Acetate Orientated Hollow/Mesoporous Magnetite Nanoparticles: Facile Synthesis, Characterization and Formation Mechanism

by Quanguo He^†

, Jun Liu^†, Jing Liang, Xiaopeng Liu, Ziyu Ding, Du Tuo and Wen Li^*

¹ School of Life Science and Chemistry, Hunan University of Technology, Zhuzhou 412007, China

^† These authors contributed equally to the work.

Appl. Sci. 2018, 8(2), 292; https://doi.org/10.3390/app8020292 - 16 Feb 2018

Cited by 48 | Viewed by 8409

Abstract

Monodispersed magnetite (Fe₃O₄) nanospheres with hollow or porous interior structures were synthesized by a facile one-pot solvothermal route. The facile synthetic process was carried out by using iron (III) chloride hexahydrate (FeCl₃·6H₂O) as only ferric [...] Read more.

Monodispersed magnetite (Fe₃O₄) nanospheres with hollow or porous interior structures were synthesized by a facile one-pot solvothermal route. The facile synthetic process was carried out by using iron (III) chloride hexahydrate (FeCl₃·6H₂O) as only ferric ion resource, and anhydrous sodium acetate (NaAc) as structure-directing agent in an ethylene glycol solution without any templates or surfactants involved. The sizes, morphologies, crystal structures and magnetic properties of hollow Fe₃O₄ NPs are characterized via Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and Vibrating sample magnetometer (VSM) techniques. The influences of reaction time, molar ratio of reactants on the morphologies and magnetic performances are also investigated. The different morphologies of magnetite (Fe₃O₄) particles were presented with tunable size ranging from 85 to 250 nm and controllable structures including porous and hollow construction by using different amount of anhydrous NaAc. A plausible mechanism based on sodium acetate assistant local Ostwald ripening is proposed for acquiring the tailorable morphology and magnetic performance. Such a design conception of anhydrous NaAc assisted Ostwald ripening applied here is a significant alternative for synthesizing hollow magnetic particles, and it could elucidate some light to understand and construct other novel hollow/mesoporous nanostructures. Full article

(This article belongs to the Section Chemical and Molecular Sciences)

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25 pages, 445 KiB

Open AccessArticle

Parallel Technique for the Metaheuristic Algorithms Using Devoted Local Search and Manipulating the Solutions Space

by Dawid Połap^1,*

, Karolina Kęsik¹, Marcin Woźniak¹

and Robertas Damaševičius²

¹ Institute of Mathematics, Silesian University of Technology, Kaszubska 23, 44-100 Gliwice, Poland

² Department of Software Engineering, Kaunas University of Technology, Studentu 50, LT-51368, Kaunas, Lithuania

Appl. Sci. 2018, 8(2), 293; https://doi.org/10.3390/app8020293 - 16 Feb 2018

Cited by 30 | Viewed by 4738

Abstract

The increasing exploration of alternative methods for solving optimization problems causes that parallelization and modification of the existing algorithms are necessary. Obtaining the right solution using the meta-heuristic algorithm may require long operating time or a large number of iterations or individuals in [...] Read more.

The increasing exploration of alternative methods for solving optimization problems causes that parallelization and modification of the existing algorithms are necessary. Obtaining the right solution using the meta-heuristic algorithm may require long operating time or a large number of iterations or individuals in a population. The higher the number, the longer the operation time. In order to minimize not only the time, but also the value of the parameters we suggest three proposition to increase the efficiency of classical methods. The first one is to use the method of searching through the neighborhood in order to minimize the solution space exploration. Moreover, task distribution between threads and CPU cores can affect the speed of the algorithm and therefore make it work more efficiently. The second proposition involves manipulating the solutions space to minimize the number of calculations. In addition, the third proposition is the combination of the previous two. All propositions has been described, tested and analyzed due to the use of various test functions. Experimental research results show that the proposed methodology for parallelization and manipulation of solution space is efficient (increasing the accuracy of solutions and reducing performance time) and it is possible to apply it also to other optimization methods. Full article

(This article belongs to the Special Issue Swarm Robotics)

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20 pages, 9229 KiB

Open AccessArticle

Numerical Study on the Seismic Performance of a Steel–Concrete Hybrid Supporting Structure in Thermal Power Plants

by Bo Wang¹, Tao Wu^1,*, Huijuan Dai² and Guoliang Bai³

¹ School of Civil Engineering, Chang’an University, Xi’an 710061, China

² School of Civil Engineering, Xi’an University of Science and Technology, Xi’an 710054, China

³ School of Civil Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China

Appl. Sci. 2018, 8(2), 294; https://doi.org/10.3390/app8020294 - 16 Feb 2018

Cited by 7 | Viewed by 6450

Abstract

This paper presents the numerical investigation on the seismic performance of a steel–concrete hybrid structure consisting of reinforced concrete (RC) tubular columns and steel braced truss with A-shaped steel frames, which is a novel supporting structural system to house air-cooled condensers (ACC) in [...] Read more.

This paper presents the numerical investigation on the seismic performance of a steel–concrete hybrid structure consisting of reinforced concrete (RC) tubular columns and steel braced truss with A-shaped steel frames, which is a novel supporting structural system to house air-cooled condensers (ACC) in large-capacity thermal power plants (TPPs). First, the finite element (FE) modeling approach for this hybrid structure using the software ABAQUS was validated by a range of pseudo-dynamic tests (PDTs) performed on a 1/8-scaled sub-structure. The failure process, lateral displacement responses, changing rules of dynamic characteristic parameters and lateral stiffness with increase of peak ground acceleration (PGA) were presented here. Then, nonlinear time-history analysis of the prototype structure was carried out. The dynamic characteristics, base shear force, lateral deformation capacity, stiffness deterioration and damage characteristics were investigated. Despite the structural complexity and irregularity, both experimental and numerical results indicate that the overall seismic performance of this steel–concrete hybrid supporting structure meets the seismic design requirements with respect to the high-intensity earthquakes. Full article

(This article belongs to the Section Mechanical Engineering)

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14 pages, 2897 KiB

Open AccessFeature PaperArticle

Separation of Light Liquid Paraffin C₅–C₉ with Cuban Volcanic Glass Previously Used in Copper Elimination from Water Solutions

by Miguel Autie-Pérez^1,*, Antonia Infantes-Molina², Juan Antonio Cecilia²

, Juan M. Labadie-Suárez¹ and Enrique Rodríguez-Castellón^1,*

¹ Departamento FQB, Facultad de Ingeniería Química, Instituto Superior Politécnico José Antonio Hechevarría, MES, La Habana 19390, Cuba

² Departamento de Química Inorgánica, Cristalografía y Mineralogía (Unidad Asociada al ICP-CSIC), Facultad de Ciencias, Universidad de Málaga, Málaga 29071, Spain

Appl. Sci. 2018, 8(2), 295; https://doi.org/10.3390/app8020295 - 17 Feb 2018

Cited by 4 | Viewed by 5001

Abstract

Featured Application: In this work, an inexpensive and available material, as volcanic glass, is used to absorb metals from wastewater and then it is used to the separation of light liquid-olefins.

Abstract: Raw porous volcanic glass from Cuba was used as an [...] Read more.

Featured Application: In this work, an inexpensive and available material, as volcanic glass, is used to absorb metals from wastewater and then it is used to the separation of light liquid-olefins.

Abstract: Raw porous volcanic glass from Cuba was used as an adsorbent for Cu²⁺ removal from dyes after activation with an acid solution. After Cu²⁺ adsorption, it was also evaluated its capacity to separate n-paraffins from a mixture by inverse gas chromatography (IGC), and the results were compared with those obtained with bare volcanic glass without copper. The main goal of this work is to highlight the great applicability of natural volcanic glass, which can be reused without pretreatment as an adsorbent. The results from copper adsorption were quite promising, considering the availability and low cost of this material; the sample without acid treatment turned out to be the most adequate to remove copper. Moreover, the results from IGC revealed that the separation of paraffins from the mixture was achieved with both bare volcanic glass and glass containing Cu, although greater heat adsorption values were obtained when copper was present in the sample due to the stronger interaction between paraffin and copper. The high availability and low cost of this porous material make it a potential and attractive candidate to be used in both heavy metal removal and paraffin separation for industrial purposes. Full article

(This article belongs to the Special Issue Nanoporous Materials and Their Applications)

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10 pages, 3333 KiB

Open AccessArticle

Structure and Sound Absorption Properties of Spiral Vane Electrospun PVA/PEO Nanofiber Membranes

by Huan Liu^1,2,* and Baoqi Zuo^1,2,*

¹ National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123, China

² College of Textile and Clothing Engineering, Soochow University, Suzhou 215021, China

Appl. Sci. 2018, 8(2), 296; https://doi.org/10.3390/app8020296 - 17 Feb 2018

Cited by 34 | Viewed by 5742

Abstract

Noise pollution has become one of the four major pollution issues in the world and has drawn much attention recently. Controlling the sound source and using sound-absorbing materials reasonably is considered an effective way to reduce noise. Due to the high porosity and [...] Read more.

Noise pollution has become one of the four major pollution issues in the world and has drawn much attention recently. Controlling the sound source and using sound-absorbing materials reasonably is considered an effective way to reduce noise. Due to the high porosity and specific surface area, nanofibers membrane is widely used in the field of the sound absorption. Polyvinyl alcohol (PVA) and Polyethylene oxide (PEO) are both water-soluble polymers with good film-forming properties that can be mixed in any proportion. In this paper, nanofiber membranes were prepared by spiral vane electrospinning with different contents of PVA and PEO. The nanofibers membranes were characterized by Fourier Transform-Infrared (FT-IR), X-ray diffraction (XRD), 3D-M, and scanning electron microscopy (SEM). The sound absorption property of nanofibers membranes and the compositions (nanofiber membranes and needle punched non-woven fabric) were tested with an impedance tube. The results demonstrate that the addition of PEO changed the morphological characteristics and construct of PVA, sound absorption properties had undergone great changes. Full article

(This article belongs to the Special Issue Acoustic Metamaterials)

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19 pages, 7265 KiB

Open AccessFeature PaperArticle

Bias Impact Analysis and Calibration of UAV-Based Mobile LiDAR System with Spinning Multi-Beam Laser Scanner

by Radhika Ravi

, Tamer Shamseldin^*, Magdy Elbahnasawy, Yun-Jou Lin and Ayman Habib

Lyles School of Civil Engineering, Purdue University, 550 West Stadium Avenue, West Lafayette, IN 47907, USA

Appl. Sci. 2018, 8(2), 297; https://doi.org/10.3390/app8020297 - 18 Feb 2018

Cited by 28 | Viewed by 7533

Abstract

Light Detection and Ranging (LiDAR) is a technology that uses laser beams to measure ranges and generates precise 3D information about the scanned area. It is rapidly gaining popularity due to its contribution to a variety of applications such as Digital Building Model [...] Read more.

Light Detection and Ranging (LiDAR) is a technology that uses laser beams to measure ranges and generates precise 3D information about the scanned area. It is rapidly gaining popularity due to its contribution to a variety of applications such as Digital Building Model (DBM) generation, telecommunications, infrastructure monitoring, transportation corridor asset management and crash/accident scene reconstruction. To derive point clouds with high positional accuracy, estimation of mounting parameters relating the laser scanners to the onboard Global Navigation Satellite System/Inertial Navigation System (GNSS/INS) unit, i.e., the lever-arm and boresight angles, is the foremost and necessary step. This paper proposes a LiDAR system calibration strategy for a Unmanned Aerial Vehicle (UAV)-based mobile mapping system that can directly estimate the mounting parameters for spinning multi-beam laser scanners through an outdoor calibration procedure. This approach is based on the use of conjugate planar/linear features in overlapping point clouds derived from different flight lines. Designing an optimal configuration for calibration is the first and foremost step in order to ensure the most accurate estimates of mounting parameters. This is achieved by conducting a rigorous theoretical analysis of the potential impact of bias in mounting parameters of a LiDAR unit on the resultant point cloud. The dependency of the impact on the orientation of target primitives and relative flight line configuration would help in deducing the configuration that would maximize as well as decouple the impact of bias in each mounting parameter so as to ensure their accurate estimation. Finally, the proposed analysis and calibration strategy are validated by calibrating a UAV-based LiDAR system using two different datasets—one acquired with flight lines at a single flying height and the other with flight lines at two different flying heights. The calibration performance is evaluated by analyzing correlation between the estimated system parameters, the a-posteriori variance factor of the Least Squares Adjustment (LSA) procedure and the quality of fit of the adjusted point cloud to planar/linear features before and after the calibration process. Full article

(This article belongs to the Special Issue Laser Scanning)

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14 pages, 2402 KiB

Open AccessArticle

Depth Image Super Resolution Based on Edge-Guided Method

by Dongsheng Zhou^*, Ruyi Wang, Jian Lu and Qiang Zhang

Key Laboratory of Advanced Design and Intelligent Computing, Ministry of Education, Dalian University, Dalian 116622, China

Appl. Sci. 2018, 8(2), 298; https://doi.org/10.3390/app8020298 - 18 Feb 2018

Cited by 13 | Viewed by 4981

Abstract

Depth image super-resolution (SR) is a technique which can reconstruct a high-resolution (HR) depth image from a low-resolution (LR) depth image. Its purpose is to obtain HR details to meet the needs of various applications in computer vision. In general, conventional depth image [...] Read more.

Depth image super-resolution (SR) is a technique which can reconstruct a high-resolution (HR) depth image from a low-resolution (LR) depth image. Its purpose is to obtain HR details to meet the needs of various applications in computer vision. In general, conventional depth image SR methods often cause edges in the final HR image to be blurred or ragged. To solve this problem, an edge-guided method for depth image SR is presented in this paper. To get high-quality edge information, a pair of sparse dictionaries was applied to reconstruct edges of depth image. Then, with the guidance of these high-quality edges, a depth image was interpolated by using a modified joint bilateral filter. Edge-guided method can preserve the sharpness of edges and effectively avoid generating blurry and ragged edges when SR is performed. Experiments showed that the proposed method can get better results on both subjective and objective evaluation, and the reconstructed performance was superior to conventional depth image SR methods. Full article

(This article belongs to the Section Optics and Lasers)

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17 pages, 3821 KiB

Open AccessArticle

Uncertainty Flow Facilitates Zero-Shot Multi-Label Learning in Affective Facial Analysis

by Wenjun Bai

, Changqin Quan^* and Zhiwei Luo

School of System Informatics, Kobe University, 1-1, Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan

Appl. Sci. 2018, 8(2), 300; https://doi.org/10.3390/app8020300 - 19 Feb 2018

Cited by 6 | Viewed by 4402

Abstract

Featured Application: The proposed Uncertainty Flow framework may benefit the facial analysis with its promised elevation in discriminability in multi-label affective classification tasks. Moreover, this framework also allows the efficient model training and between tasks knowledge transfer. The applications that rely heavily on [...] Read more.

Featured Application: The proposed Uncertainty Flow framework may benefit the facial analysis with its promised elevation in discriminability in multi-label affective classification tasks. Moreover, this framework also allows the efficient model training and between tasks knowledge transfer. The applications that rely heavily on continuous prediction on emotional valance, e.g., to monitor prisoners’ emotional stability in jail, can be directly benefited from our framework.

Abstract: To lower the single-label dependency on affective facial analysis, it urges the fruition of multi-label affective learning. The impediment to practical implementation of existing multi-label algorithms pertains to scarcity of scalable multi-label training datasets. To resolve this, an inductive transfer learning based framework, i.e.,Uncertainty Flow, is put forward in this research to allow knowledge transfer from a single labelled emotion recognition task to a multi-label affective recognition task. I.e., the model uncertainty—which can be quantified in Uncertainty Flow—is distilled from a single-label learning task. The distilled model uncertainty ensures the later efficient zero-shot multi-label affective learning. On the theoretical perspective, within our proposed Uncertainty Flow framework, the feasibility of applying weakly informative priors, e.g., uniform and Cauchy prior, is fully explored in this research. More importantly, based on the derived weight uncertainty, three sets of prediction related uncertainty indexes, i.e., soft-max uncertainty, pure uncertainty and uncertainty plus are proposed to produce reliable and accurate multi-label predictions. Validated on our manual annotated evaluation dataset, i.e., the multi-label annotated FER2013, our proposed Uncertainty Flow in multi-label facial expression analysis exhibited superiority to conventional multi-label learning algorithms and multi-label compatible neural networks. The success of our proposed Uncertainty Flow provides a glimpse of future in continuous, uncertain, and multi-label affective computing. Full article

(This article belongs to the Special Issue Socio-Cognitive and Affective Computing)

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12 pages, 5054 KiB

Open AccessFeature PaperArticle

Infrared Thermography for Inline Monitoring of Glass/Epoxy under Impact and Quasi-Static Bending

by Carosena Meola^*

, Simone Boccardi and Giovanni Maria Carlomagno

Department of Industrial Engineering, Aerospace Division, University of Naples Federico II, 80138 Naples, Italy

Appl. Sci. 2018, 8(2), 301; https://doi.org/10.3390/app8020301 - 19 Feb 2018

Cited by 10 | Viewed by 4074

Abstract

Abstract: In this work, glass/epoxy has been chosen as case study as it represents the most-used composite material, being appropriate for a vast variety of applications and a reasonable performance/cost compromise. This material has already been inline impact-monitored with infrared thermography, mostly for [...] Read more.

Abstract: In this work, glass/epoxy has been chosen as case study as it represents the most-used composite material, being appropriate for a vast variety of applications and a reasonable performance/cost compromise. This material has already been inline impact-monitored with infrared thermography, mostly for feasibility tests. Now, impact tests are repeated by changing some parameters and by inline monitoring simultaneously with two different infrared cameras to share a high frame rate and spatial resolution at the same time. In addition, glass/epoxy is monitored also while it is under quasi-static bending tests. The aim of this paper is to show what it is possible to learn from thermal signatures developing in the same material when it is either impacted or under quasi-static bending. Full article

(This article belongs to the Special Issue Novel Ideas for Infrared Thermography also Applied in Integrated Approaches)

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18 pages, 8077 KiB

Open AccessArticle

Designing the Mind of a Social Robot

by Nicole Lazzeri^1,*,†

, Daniele Mazzei^1,†, Lorenzo Cominelli^2,†

, Antonio Cisternino^1,†

and Danilo Emilio De Rossi^2,†

¹ Computer Science Department, University of Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, Italy

² Research Center “E. Piaggio”, University of Pisa, Via Diotisalvi 1, 56122 Pisa, Italy

^† These authors contributed equally to this work.

Appl. Sci. 2018, 8(2), 302; https://doi.org/10.3390/app8020302 - 19 Feb 2018

Cited by 35 | Viewed by 9109

Abstract

Humans have an innate tendency to anthropomorphize surrounding entities and have always been fascinated by the creation of machines endowed with human-inspired capabilities and traits. In the last few decades, this has become a reality with enormous advances in hardware performance, computer graphics, [...] Read more.

Humans have an innate tendency to anthropomorphize surrounding entities and have always been fascinated by the creation of machines endowed with human-inspired capabilities and traits. In the last few decades, this has become a reality with enormous advances in hardware performance, computer graphics, robotics technology, and artificial intelligence. New interdisciplinary research fields have brought forth cognitive robotics aimed at building a new generation of control systems and providing robots with social, empathetic and affective capabilities. This paper presents the design, implementation, and test of a human-inspired cognitive architecture for social robots. State-of-the-art design approaches and methods are thoroughly analyzed and discussed, cases where the developed system has been successfully used are reported. The tests demonstrated the system’s ability to endow a social humanoid robot with human social behaviors and with in-silico robotic emotions. Full article

(This article belongs to the Special Issue Social Robotics)

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20 pages, 7116 KiB

Open AccessArticle

Cloud Incubator Car: A Reliable Platform for Autonomous Driving

by Raúl Borraz^*, Pedro J. Navarro

, Carlos Fernández and Pedro María Alcover

¹ División de Sistemas en Ingeniería Electrónica (DSIE), Universidad Politécnica de Cartagena, Campus Muralla del Mar, s/n, 30202 Cartagena, Spain

^† These authors contributed equally to this work.

Appl. Sci. 2018, 8(2), 303; https://doi.org/10.3390/app8020303 - 20 Feb 2018

Cited by 20 | Viewed by 7340

Abstract

It appears clear that the future of road transport is going through enormous changes (intelligent transport systems), the main one being the Intelligent Vehicle (IV). Automated driving requires a huge research effort in multiple technological areas: sensing, control, and driving algorithms. We present [...] Read more.

It appears clear that the future of road transport is going through enormous changes (intelligent transport systems), the main one being the Intelligent Vehicle (IV). Automated driving requires a huge research effort in multiple technological areas: sensing, control, and driving algorithms. We present a comprehensible and reliable platform for autonomous driving technology development as well as for testing purposes, developed in the Intelligent Vehicles Lab at the Technical University of Cartagena. We propose an open and modular architecture capable of easily integrating a wide variety of sensors and actuators which can be used for testing algorithms and control strategies. As a proof of concept, this paper presents a reliable and complete navigation application for a commercial vehicle (Renault Twizy). It comprises a complete perception system (2D LIDAR, 3D HD LIDAR, ToF cameras, Real-Time Kinematic (RTK) unit, Inertial Measurement Unit (IMU)), an automation of the driving elements of the vehicle (throttle, steering, brakes, and gearbox), a control system, and a decision-making system. Furthermore, two flexible and reliable algorithms are presented for carrying out global and local route planning on board autonomous vehicles. Full article

(This article belongs to the Special Issue Road Vehicles Surroundings Supervision: On-Board Sensors and Communications)

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18 pages, 5688 KiB

Open AccessArticle

The Conversion of Wollastonite to CaCO3 Considering Its Use for CCS Application as Cementitious Material

by Kristoff Svensson^*, Andreas Neumann, Flora Feitosa Menezes, Christof Lempp and Herbert Pöllmann

Institute for Geosciences and Geography, Martin-Luther-University of Halle-Wittenberg, Von-Seckendorff-Platz 3, 06120 Halle (Saale), Germany

Appl. Sci. 2018, 8(2), 304; https://doi.org/10.3390/app8020304 - 20 Feb 2018

Cited by 38 | Viewed by 7266

Abstract

The reaction of wollastonite (CaSiO3) with CO2 in the presence of aqueous solutions (H2O) and varied temperature conditions (296 K, 323 K, and 333 K) was investigated. The educts (CaSiO3) and the products (CaCO3 and SiO2) were analyzed by scanning electron microscopy (SEM), [...] Read more.

The reaction of wollastonite (CaSiO3) with CO2 in the presence of aqueous solutions (H2O) and varied temperature conditions (296 K, 323 K, and 333 K) was investigated. The educts (CaSiO3) and the products (CaCO3 and SiO2) were analyzed by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), and differential scanning calorimetry with thermogravimetry coupled with a mass spectrometer and infrared spectrometer (DSC TG/MS/IR). The reaction rate increased significantly at higher temperatures and seemed less dependent on applied pressure. It could be shown that under the defined conditions wollastonite can be applied as a cementitious material for sealing wells considering CCS applications, because after 24 h the degree of conversion from CaSiO3 to CaCO3 at 333 K was very high (>90%). As anticipated, the most likely application of wollastonite as a cementitious material in CCS would be for sealing the well after injection of CO2 in the reservoir. Full article

(This article belongs to the Section Chemical and Molecular Sciences)

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13 pages, 842 KiB

Open AccessArticle

Predicting Human Behaviour with Recurrent Neural Networks

by Aitor Almeida^*,†

and Gorka Azkune^†

¹ DeustoTech-Deusto Foundation, University of Deusto, Av. Universidades 24, 48007 Bilbao, Spain

^† These authors contributed equally to this work.

Appl. Sci. 2018, 8(2), 305; https://doi.org/10.3390/app8020305 - 20 Feb 2018

Cited by 88 | Viewed by 9974

Abstract

As the average age of the urban population increases, cities must adapt to improve the quality of life of their citizens. The City4Age H2020 project is working on the early detection of the risks related to mild cognitive impairment and frailty and on [...] Read more.

As the average age of the urban population increases, cities must adapt to improve the quality of life of their citizens. The City4Age H2020 project is working on the early detection of the risks related to mild cognitive impairment and frailty and on providing meaningful interventions that prevent these risks. As part of the risk detection process, we have developed a multilevel conceptual model that describes the user behaviour using actions, activities, and intra- and inter-activity behaviour. Using this conceptual model, we have created a deep learning architecture based on long short-term memory networks (LSTMs) that models the inter-activity behaviour. The presented architecture offers a probabilistic model that allows us to predict the user’s next actions and to identify anomalous user behaviours. Full article

(This article belongs to the Special Issue Socio-Cognitive and Affective Computing)

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14 pages, 4204 KiB

Open AccessFeature PaperArticle

From Thermal Inspection to Updating a Numerical Model of a Race Bicycle: Comparison with Structural Dynamics Approach

by Gunther Steenackers^*,†

, Jeroen Peeters

, Simon Verspeek and Bart Ribbens

¹ Deptartment Electromechanics, University of Antwerp, Op3Mech research group, Groenenborgerlaan 171, B-2020 Antwerp, Belgium

^† Additional affiliation: Deptartment Electromechanics, Deptartment Mechanical Engineering, Acoustics & Vibration Research Group, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.

Appl. Sci. 2018, 8(2), 307; https://doi.org/10.3390/app8020307 - 21 Feb 2018

Cited by 2 | Viewed by 3827

Abstract

Carbon fiber bicycle frames are complex-shaped structures and are prone to delaminations and difficult to inspect. The use of finite element model updating is common in structural dynamics but not so common in active thermography inspection. However, there are many advantages to using [...] Read more.

Carbon fiber bicycle frames are complex-shaped structures and are prone to delaminations and difficult to inspect. The use of finite element model updating is common in structural dynamics but not so common in active thermography inspection. However, there are many advantages to using thermography when inspecting bicycle frames. These include the fact that the inspection can be performed in situ, can cover large areas, and is a quantitative method. In this paper, a numerical model of a bicycle frame will be updated and optimized by the surface temperature distribution captured with pulsed thermography. These results will be compared and benchmarked against frequency response function (FRF) measurement data as a reference. The chosen temperature decay measurements to be used as reference data will be of key importance. The goal of this manuscript is to compare both measurement results and model predictabilities after performing finite element model updating with respect to accuracy and speed. Full article

(This article belongs to the Special Issue Novel Ideas for Infrared Thermography also Applied in Integrated Approaches)

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15 pages, 5846 KiB

Open AccessArticle

Excitation of Wet Perovskite Films by Ultrasonic Vibration Improves the Device Performance

by Mohammad-Reza Ahmadian-Yazdi

, Mehran Habibi

and Morteza Eslamian^*

University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai 200240, China

Appl. Sci. 2018, 8(2), 308; https://doi.org/10.3390/app8020308 - 21 Feb 2018

Cited by 21 | Viewed by 6621

Abstract

In this work, a novel, facile, and low-cost mechanical post treatment technique, i.e., ultrasonic substrate vibration post treatment (SVPT) is applied on wet spun perovskite layers. The effect of varying the time of the SVPT on the characteristics of the perovskite crystals and [...] Read more.

In this work, a novel, facile, and low-cost mechanical post treatment technique, i.e., ultrasonic substrate vibration post treatment (SVPT) is applied on wet spun perovskite layers. The effect of varying the time of the SVPT on the characteristics of the perovskite crystals and the perovskite film is studied, in order to achieve the optimum time duration of the SVPT. Among the results, it is found that the application of only three minutes of the SVPT (for the ultrasonic vibration assembly used in this study, operated at 40 kHz) brings about significant improvement in the film coverage, and the contact between the perovskite and the m-TiO₂ layers, owing to the effective penetration of the perovskite solution into the pores, leading to a superior charge transfer, and a significant increase in the device power conversion efficiency (PCE), when compared to the control device. This unprecedented effect is repeatable when applied on both single and mixed halide perovskites, putting forward a reliable and low-cost mechanical technique for the fabrication of perovskite solar cells (PSCs) in the lab and beyond, which could reduce or eliminate the tedious and expensive chemical optimization treatments, commonly used to increase the PCE. Full article

(This article belongs to the Section Acoustics and Vibrations)

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10 pages, 3023 KiB

Open AccessArticle

Synthesis of Aligned TiO₂ Nanofibers Using Electrospinning

by Jae-Hun Kim, Jae-Hyoung Lee, Jin-Young Kim and Sang Sub Kim^*

Department of Materials Science and Engineering, Inha University, Incheon 22212, Korea

Appl. Sci. 2018, 8(2), 309; https://doi.org/10.3390/app8020309 - 21 Feb 2018

Cited by 44 | Viewed by 6462

Abstract

In this work, aligned TiO₂ nanofibers (NFs) were synthesized using an electrospinning technique with a two-piece Al collector. The effects of processing parameters, including the calcination temperature, applied voltage, and needle-to-Al-collector distance, were studied. The final phase of TiO₂ was determined [...] Read more.

In this work, aligned TiO₂ nanofibers (NFs) were synthesized using an electrospinning technique with a two-piece Al collector. The effects of processing parameters, including the calcination temperature, applied voltage, and needle-to-Al-collector distance, were studied. The final phase of TiO₂ was determined using the calcination temperature; calcination at 500 °C resulted in the formation of anatase phase, whereas calcination at 600 °C resulted in the formation of rutile phase. In addition, with the increase of calcination temperature, the diameter of the synthesized NFs decreased owing to the sintering and coalescence of nanograins existing in individual NFs. A specially designed collector configuration resulted in the parallel alignment of TiO₂ NFs. The needle-to-collector distance and applied voltages caused the change in diameter and alignment of NFs. The diameter had an inverse relation with the needle-to-collector distance, and an optimal value of applied voltage was required to achieve TiO₂ NFs with the smallest diameter. Furthermore, with the increase of applied voltage, the morphology of TiO₂ NFs changed from an aligned to a disordered state. Full article

(This article belongs to the Section Nanotechnology and Applied Nanosciences)

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15 pages, 3329 KiB

Open AccessArticle

Effects of Post-Synthesis Activation and Relative Humidity on Adsorption Performance of ZIF-8 for Capturing Toluene from a Gas Phase in a Continuous Mode

by Saeed Jafari¹

, Farshid Ghorbani-Shahna^1,*, Abdulrahman Bahrami² and Hossein Kazemian³

¹ Center of Excellence for Occupational Health and Research Center for Health Science, School of Public Health, Hamadan University of Medical Sciences, Hamadan 6517838736, Iran

² Occupational Health and Safety Research Center, School of Public Health, Hamadan University of Medical Sciences, Hamadan 6517838736, Iran

³ College of Science and Management, University of Northern British Columbia, Prince George, BC V2N 4Z9, Canada

Appl. Sci. 2018, 8(2), 310; https://doi.org/10.3390/app8020310 - 22 Feb 2018

Cited by 26 | Viewed by 9159

Abstract

Zeolitic imidazolate framework-8 (ZIF-8) was used as an adsorbent for the removal of toluene in its gas phase at different relative humidity (RH). High-purity ZIF-8 with an average particle size of 0.64 µm synthesized from an aqueous solution at room temperature, and then [...] Read more.

Zeolitic imidazolate framework-8 (ZIF-8) was used as an adsorbent for the removal of toluene in its gas phase at different relative humidity (RH). High-purity ZIF-8 with an average particle size of 0.64 µm synthesized from an aqueous solution at room temperature, and then characterized by X-ray diffraction (XRD), fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) techniques. Dynamic adsorption (continuous mode) experiments of toluene on ZIF-8 were studied using breakthrough curves. The effects of thermal pretreatment (activation) under dry air and N₂ atmospheres on the adsorbent performances was studied. ZIF-8 activated at 300 °C for 3 h under dry air showed the highest adsorption capacity of 562.17 mg∙g⁻¹. Furthermore, it was observed that the adsorption of toluene on ZIF-8 was significantly decreased at 80% RH. The experimental data of dynamic adsorption well fitted into the Thomas and Yan mathematical models. Full article

(This article belongs to the Special Issue Sustainable Environmental Remediation)

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15 pages, 4342 KiB

Open AccessArticle

Experimental Study on Streamwise Vortex-Induced Vibration of a Flexible, Slender Cylinder

by Wanhai Xu^1,2

, Wenqi Qin¹ and Xifeng Gao^1,*

¹ State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300072, China

² Collaborative Innovation Centre for Advanced Ship and Deep-Sea Exploration, Shanghai 200240, China

Appl. Sci. 2018, 8(2), 311; https://doi.org/10.3390/app8020311 - 22 Feb 2018

Cited by 10 | Viewed by 4478

Abstract

Laboratory tests on streamwise vortex-induced vibration (VIV) of a flexible, slender cylinder were carried out in a towing tank. A cylinder model, 20 mm in diameter and 3.91 m in length, was towed horizontally to generate a uniform profile of relative velocity in [...] Read more.

Laboratory tests on streamwise vortex-induced vibration (VIV) of a flexible, slender cylinder were carried out in a towing tank. A cylinder model, 20 mm in diameter and 3.91 m in length, was towed horizontally to generate a uniform profile of relative velocity in calm water. The aspect ratio (length to diameter) and mass ratio (structural mass to displaced fluid mass) of the cylinder were 195.5 and 1.39, respectively. The Reynolds number was in the range of 1000–3000. The displacement amplitudes and vibration frequencies were investigated in order to examine the dynamic characteristics of the flexible cylinder undergoing streamwise VIV. Experimental results indicated that there were two detached branches in the streamwise response curve, i.e., the first excitation region (1.0 < Vr < 2.6) and the second excitation region (2.6 < Vr < 4.0). This phenomenon is similar to the streamwise VIV of an elastically-mounted rigid cylinder, except that a larger and shifted peak was observed in the second branch in this study. The cylinder’s linear orbits in the first excitation region indicated that the streamwise vibration frequency was equivalent to its transverse counterpart. However, in the second excitation region, the cylinder’s motion showed a figure-of-eight pattern, and the streamwise frequency was twice that in the transverse direction. In addition, two curve-fitted formulae of the maximum displacement amplitudes in the first and second excitation regions, versus the reduced mass-damping parameter, were proposed. This was accomplished by compiling the published streamwise VIV data and those in the present research work. Full article

(This article belongs to the Section Mechanical Engineering)

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15 pages, 3215 KiB

Open AccessArticle

Thermal Characteristics of Plastic Film Tension in Roll-to-Roll Gravure Printed Electronics

by Kui He^1,3

, Shanhui Liu^2,*, Kedian Wang¹ and Xuesong Mei¹

¹ School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, China

² Faculty of Printing, Packaging Engineering and Digital Media Technology, Xi’an University of Technology, Xi’an 710048, Shaanxi, China

³ School of Mechanical Engineering, Henan University of Science and Technology, Luoyang 471003, Henan, China

Appl. Sci. 2018, 8(2), 312; https://doi.org/10.3390/app8020312 - 23 Feb 2018

Cited by 9 | Viewed by 5307

Abstract

In the printing section of a roll-to-roll gravure printed electronics machine, the plastic film tension is directly associated with the product quality. The temperature distribution of the plastic film in the printing section is non-uniform, because of the higher drying temperature and the [...] Read more.

In the printing section of a roll-to-roll gravure printed electronics machine, the plastic film tension is directly associated with the product quality. The temperature distribution of the plastic film in the printing section is non-uniform, because of the higher drying temperature and the lower room temperature. Furthermore, the drying temperature and the room temperature are not constants in industrial production. As the plastic film is sensitive to temperature, the temperature of the plastic film will affects the web tension in the printing section. In this paper, the thermal characteristics of the plastic film tension in roll-to-roll gravure printed electronics are studied in order to help to improve the product quality. First, the tension model including the factor of temperature is derived based on the law of mass conservation. Then, some simulations and experiments are carried out in order to in-depth research the effects of the drying temperature and room temperature based on the relations between system inputs and outputs. The results show that the drying temperature and room temperature have significant influences on the web tension. The research on the thermal characteristics of plastic film tension would benefit the tension control accuracy for further study. Full article

(This article belongs to the Special Issue Printed Electronics 2017)

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15 pages, 4179 KiB

Open AccessArticle

A Multi-Agent System for the Dynamic Emplacement of Electric Vehicle Charging Stations

by Jaume Jordán^*,†

, Javier Palanca^†

, Elena Del Val^†

, Vicente Julian^†

and Vicente Botti^†

¹ Departamento de Sistemas Informáticos y Computación, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain

^† These authors contributed equally to this work.

Appl. Sci. 2018, 8(2), 313; https://doi.org/10.3390/app8020313 - 23 Feb 2018

Cited by 30 | Viewed by 5713

Abstract

One of the main current challenges of electric vehicles (EVs) is the creation of a reliable, accessible and comfortable charging infrastructure for citizens in order to enhance demand. In this paper, a multi-agent system (MAS) is proposed to facilitate the analysis of different [...] Read more.

One of the main current challenges of electric vehicles (EVs) is the creation of a reliable, accessible and comfortable charging infrastructure for citizens in order to enhance demand. In this paper, a multi-agent system (MAS) is proposed to facilitate the analysis of different placement configurations for EV charging stations. The proposed MAS integrates information from heterogeneous data sources as a starting point to characterize the areas where charging stations could potentially be placed. Through a genetic algorithm, the MAS is able to analyze a large number of possible configurations, taking into account a set of criteria to be optimized. Finally, the MAS returns a configuration with the areas of the city that are considered most appropriate for the establishment of charging stations according to the specified criteria. Full article

(This article belongs to the Special Issue Multi-Agent Systems)

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23 pages, 22557 KiB

Open AccessArticle

Geo-Proxy-Based Site Classification for Regional Zonation of Seismic Site Effects in South Korea

by Chang-Guk Sun¹, Han-Saem Kim^2,*

and Hyung-Ik Cho²

¹ Geological Research Division, Korea Institute of Geoscience and Mineral Resources, Daejeon 305-350, Korea

² Earthquake Research Center, Korea Institute of Geoscience and Mineral Resources, Daejeon 305-350, Korea

Appl. Sci. 2018, 8(2), 314; https://doi.org/10.3390/app8020314 - 24 Feb 2018

Cited by 12 | Viewed by 7069

Abstract

Seismic site effects and topographic effects related to ground motion occur during an earthquake due to site-specific geotechnical or geological characteristics, including the geological or geographical structure and the characteristics of near-surface sub-soil layers. Site-specific site effects due to geological conditions have been [...] Read more.

Seismic site effects and topographic effects related to ground motion occur during an earthquake due to site-specific geotechnical or geological characteristics, including the geological or geographical structure and the characteristics of near-surface sub-soil layers. Site-specific site effects due to geological conditions have been confirmed in recent earthquake events. Earthquake-induced damage has mainly occurred at accumulated soft soil layers under basins or along coasts and rivers. An alternative method has recently been proposed for evaluating regional seismic site effects and amplification factors using digital elevation models (DEM). High-quality DEMs at high resolutions may be employed to resolve finer-scale variations in topographic gradients and consequently, correlated site response parameters. Because there are many regions in South Korea lacking borehole datasets, which are insufficient for site classification only using borehole datasets, a DEM-based proxy for seismic zonation can be effective. Thus, in this study, geo-proxy-based site classification was proposed based on empirical correlations with site response parameters and conducted for regional zonation of seismic site effects to identify the amplification of characteristics in the western metropolitan areas of South Korea, depending on the site-specific geo-spatial conditions. Full article

(This article belongs to the Special Issue Seismic Metamaterials)

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13 pages, 3503 KiB

Open AccessArticle

Forecast for Artificial Muscle Tremor Behavior Based on Dynamic Additional Grey Catastrophe Prediction

by Yu Fu¹

, Jianjun Yao¹, Honghao Zhao^2,*

, Gang Zhao¹ and Zhenshuai Wan¹

¹ Institute of Intelligent Manufacturing and Robotics, College of Mechanical and Electrical Engineering, Harbin Engineering University, Harbin 150001, China

² Department of Decision Science, School of Business, Macau University of Science and Technology, Macau 999078, China

Appl. Sci. 2018, 8(2), 315; https://doi.org/10.3390/app8020315 - 24 Feb 2018

Cited by 5 | Viewed by 4652

Abstract

Recently, bio-inspired artificial muscles based on ionic polymers have shown a bright perspective in engineering and medical research, but the inherent tremor behavior can cause instability of output response. In this paper, dynamic additional grey catastrophe prediction (DAGCP) is proposed to forecast the [...] Read more.

Recently, bio-inspired artificial muscles based on ionic polymers have shown a bright perspective in engineering and medical research, but the inherent tremor behavior can cause instability of output response. In this paper, dynamic additional grey catastrophe prediction (DAGCP) is proposed to forecast the occurrence time of tremor behavior, providing adequate preparation time for the suppression of the chitosan-based artificial muscles. DAGCP constructs various dimensions of time subsequence models under different starting points based on the threshold of tremor occurrence times and peak-to-peak values in unit time. Next, the appropriate subsequence is selected according to grey correlation degree and prediction accuracy, then it is updated with the newly generated values to achieve a real-time forecast of forthcoming tremor time. Compared with conventional grey catastrophe prediction (GCP), the proposed method has the following advantages: (1) the degradation of prediction accuracy caused by the immobilization of original parameters is prevented; (2) the dynamic input, real-time update and gradual forecast of time sequence are incorporated into the model. The experiment results show that the novel DAGCP can predict forthcoming tremor time earlier and more accurately than the conventional GCP. The generation mechanism of tremor behavior is illustrated as well. Full article

(This article belongs to the Section Materials Science and Engineering)

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14 pages, 3193 KiB

Open AccessFeature PaperArticle

A Multi-Usable Cloud Service Platform: A Case Study on Improved Development Pace and Efficiency

by John Lindström^1,*

, Anders Hermanson², Fredrik Blomstedt³ and Petter Kyösti¹

¹ ProcessIT Innovations R&D Centre, Luleå University of Technology, 971 87 Luleå, Sweden

² Adage AB, C/O BnearIT, Stationsgatan 69, 972 34 Luleå, Sweden

³ BnearIT AB, Stationsgatan 69, 972 34 Luleå, Sweden

Appl. Sci. 2018, 8(2), 316; https://doi.org/10.3390/app8020316 - 24 Feb 2018

Cited by 37 | Viewed by 6066

Abstract

The case study, spanning three contexts, concerns a multi-usable cloud service platform for big data collection and analytics and how the development pace and efficiency of it has been improved by 50–75% by using the Arrowhead framework and changing development processes/practices. Furthermore, additional [...] Read more.

The case study, spanning three contexts, concerns a multi-usable cloud service platform for big data collection and analytics and how the development pace and efficiency of it has been improved by 50–75% by using the Arrowhead framework and changing development processes/practices. Furthermore, additional results captured during the case study are related to technology, competencies and skills, organization, management, infrastructure, and service and support. A conclusion is that when offering a complex offer such as an Industrial Product-Service System, comprising sensors, hardware, communications, software, cloud service platform, etc., it is necessary that the technology, business model, business setup, and organization all go hand in hand during the development and later operation, as all ‘components’ are required for a successful result. Full article

(This article belongs to the Special Issue Smart Sustainable Manufacturing Systems)

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12 pages, 1771 KiB

Open AccessArticle

Perceptual Image Hashing Using Latent Low-Rank Representation and Uniform LBP

by Hengfu Yang^1,2,*

, Jianping Yin^2,* and Mingfang Jiang¹

¹ Department of Information Science and Engineering, Hunan First Normal University, Changsha 410205, China

² School of Computer Science and Network Security, Dongguan University of Technology, Dongguan 523808, China

Appl. Sci. 2018, 8(2), 317; https://doi.org/10.3390/app8020317 - 24 Feb 2018

Cited by 16 | Viewed by 4964

Abstract

Robustness and discriminability are the two most important features of perceptual image hashing (PIH) schemes. In order to achieve a good balance between perceptual robustness and discriminability, a novel PIH algorithm is proposed by combining latent low-rank representation (LLRR) and rotation invariant uniform [...] Read more.

Robustness and discriminability are the two most important features of perceptual image hashing (PIH) schemes. In order to achieve a good balance between perceptual robustness and discriminability, a novel PIH algorithm is proposed by combining latent low-rank representation (LLRR) and rotation invariant uniform local binary patterns (RiuLBP). LLRR is first applied on resized original images to the principal feature matrix and to the salient feature matrix, since it can automatically extract salient features from corrupted images. Following this, Riulocal bin features are extracted from each non-overlapping block of the principal feature matrix and of the salient feature matrix, respectively. All features are concatenated and scrambled to generate final binary hash code. Experimental results show that the proposed hashing algorithm is robust against many types of distortions and attacks, such as noise addition, low-pass filtering, rotation, scaling, and JPEG compression. It outperforms other local binary patterns (LBP) based image hashing schemes in terms of perceptual robustness and discriminability. Full article

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Review

Jump to: Editorial, Research

31 pages, 8380 KiB

Open AccessReview

Retinal Vessels Segmentation Techniques and Algorithms: A Survey

by Jasem Almotiri^1,*, Khaled Elleithy¹

and Abdelrahman Elleithy²

¹ Computer Science and Engineering Department, University of Bridgeport, 126 Park Ave, Bridgeport, CT 06604, USA

² Computer Science Department, William Paterson University, 300 Pompton Rd, Wayne, NJ 07470, USA

Appl. Sci. 2018, 8(2), 155; https://doi.org/10.3390/app8020155 - 23 Jan 2018

Cited by 116 | Viewed by 12331

Abstract

Retinal vessels identification and localization aim to separate the different retinal vasculature structure tissues, either wide or narrow ones, from the fundus image background and other retinal anatomical structures such as optic disc, macula, and abnormal lesions. Retinal vessels identification studies are attracting [...] Read more.

Retinal vessels identification and localization aim to separate the different retinal vasculature structure tissues, either wide or narrow ones, from the fundus image background and other retinal anatomical structures such as optic disc, macula, and abnormal lesions. Retinal vessels identification studies are attracting more and more attention in recent years due to non-invasive fundus imaging and the crucial information contained in vasculature structure which is helpful for the detection and diagnosis of a variety of retinal pathologies included but not limited to: Diabetic Retinopathy (DR), glaucoma, hypertension, and Age-related Macular Degeneration (AMD). With the development of almost two decades, the innovative approaches applying computer-aided techniques for segmenting retinal vessels are becoming more and more crucial and coming closer to routine clinical applications. The purpose of this paper is to provide a comprehensive overview for retinal vessels segmentation techniques. Firstly, a brief introduction to retinal fundus photography and imaging modalities of retinal images is given. Then, the preprocessing operations and the state of the art methods of retinal vessels identification are introduced. Moreover, the evaluation and validation of the results of retinal vessels segmentation are discussed. Finally, an objective assessment is presented and future developments and trends are addressed for retinal vessels identification techniques. Full article

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40 pages, 6634 KiB

Open AccessReview

Nanofiber-Based Materials for Persistent Organic Pollutants in Water Remediation by Adsorption

by Elise Des Ligneris^*

, Ludovic F. Dumée

and Lingxue Kong

Institute for Frontier Materials, Deakin University, Geelong VIC 3220, Australia

Appl. Sci. 2018, 8(2), 166; https://doi.org/10.3390/app8020166 - 24 Jan 2018

Cited by 37 | Viewed by 8056

Abstract

Fresh water is one of the most precious resources for our society. As a cause of oxygen depletion, organic pollutants released into water streams from industrial discharges, fertilizers, pesticides, detergents or consumed medicines can raise toxicological concerns due to their long-range transportability, bio-accumulation [...] Read more.

Fresh water is one of the most precious resources for our society. As a cause of oxygen depletion, organic pollutants released into water streams from industrial discharges, fertilizers, pesticides, detergents or consumed medicines can raise toxicological concerns due to their long-range transportability, bio-accumulation and degradation into carcinogenic compounds. The Stockholm Convention has named 21 persistent organic pollutants (POP) so far. As opposed to other separation techniques, adsorption, typically performed with activated carbons, offers opportunities to combine low operation costs with high performance as well as fast kinetics of capture if custom-designed with the right choice of adsorbent structure and surface chemistry. Nanofibers possess a higher surface to volume ratio compared to commercial macro-adsorbents, and a higher stability in water than other adsorptive nanostructures, such as loose nanoparticles. This paper highlights the potential of nanofibers in organic pollutant adsorption and thus provides an up-to-date overview of their employment for the treatment of wastewater contaminated by disinfectants and pesticides, which is benchmarked with other reported adsorptive structures. The discussion further investigates the impact of adsorbent pore geometry and surface chemistry on the resulting adsorption performance against specific organic molecules. Finally, insight into the physicochemical properties required for an adsorbent against a targeted pollutant is provided. Full article

(This article belongs to the Special Issue Nanotechnology in Wastewater Treatment Technology)

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16 pages, 1771 KiB

Open AccessReview

Nanomaterials for the Abatement of Pharmaceuticals and Personal Care Products from Wastewater

by Francesca Stefania Freyria^1,2,3, Francesco Geobaldo¹ and Barbara Bonelli^1,2,*

¹ Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy

² INSTM Unit of Torino-Politecnico, Corso Duca degli Abruzzi 24, 10129 Torino, Italy

³ Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA

Appl. Sci. 2018, 8(2), 170; https://doi.org/10.3390/app8020170 - 25 Jan 2018

Cited by 57 | Viewed by 6706

Abstract

In this short-review, the most common types of both pharmaceutical and personal care products (PPCP, a class of “emerging pollutants”) are considered, as well as some of the most frequent methods for their removal that envisage the use of nanomaterials. The nanomaterials used [...] Read more.

In this short-review, the most common types of both pharmaceutical and personal care products (PPCP, a class of “emerging pollutants”) are considered, as well as some of the most frequent methods for their removal that envisage the use of nanomaterials. The nanomaterials used in conservative methods (namely, reverse osmosis, nanofiltration and adsorption) are basically nanoporous solids. Non-conservative methods, which include photocatalysis and Fenton reaction, are currently considered more promising than conservative ones, as the former allow the (at least) partial degradation of the original molecules into more biodegradable by-products, which can be further abated by subsequent biological treatments, whereas the former are not efficient for the removal of small quantities of pollutants and have to be regenerated. Full article

(This article belongs to the Special Issue Nanotechnology in Wastewater Treatment Technology)

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23 pages, 5502 KiB

Open AccessFeature PaperReview

Recent Progress in Synthesis and Functionalization of Multimodal Fluorescent-Magnetic Nanoparticles for Biological Applications

by Raquel Serrano García, Shelley Stafford

and Yurii K. Gun’ko^*

School of Chemistry and Crann, University of Dublin, Trinity College, Dublin 2, Ireland

Appl. Sci. 2018, 8(2), 172; https://doi.org/10.3390/app8020172 - 25 Jan 2018

Cited by 64 | Viewed by 10015

Abstract

There is a great interest in the development of new nanomaterials for multimodal imaging applications in biology and medicine. Multimodal fluorescent-magnetic based nanomaterials deserve particular attention as they can be used as diagnostic and drug delivery tools, which could facilitate the diagnosis and [...] Read more.

There is a great interest in the development of new nanomaterials for multimodal imaging applications in biology and medicine. Multimodal fluorescent-magnetic based nanomaterials deserve particular attention as they can be used as diagnostic and drug delivery tools, which could facilitate the diagnosis and treatment of cancer and many other diseases. This review focuses on the recent developments of magnetic-fluorescent nanocomposites and their biomedical applications. The recent advances in synthetic strategies and approaches for the preparation of fluorescent-magnetic nanocomposites are presented. The main biomedical uses of multimodal fluorescent-magnetic nanomaterials, including biological imaging, cancer therapy and drug delivery, are discussed, and prospects of this field are outlined. Full article

(This article belongs to the Special Issue Biological Applications of Magnetic Nanoparticles)

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22 pages, 5376 KiB

Open AccessFeature PaperReview

Light Scattering by a Dielectric Sphere: Perspectives on the Mie Resonances

by Dimitrios Tzarouchis^*

and Ari Sihvola

Department of Electronics and Nanoengineering, Aalto University, Maarintie 8, 02150 Espoo, Finland

Appl. Sci. 2018, 8(2), 184; https://doi.org/10.3390/app8020184 - 26 Jan 2018

Cited by 156 | Viewed by 21353

Abstract

Light scattering by a small spherical particle, a central topic for electromagnetic scattering theory, is here considered. In this short review, some of the basic features of its resonant scattering behavior are covered. First, a general physical picture is described by a full [...] Read more.

Light scattering by a small spherical particle, a central topic for electromagnetic scattering theory, is here considered. In this short review, some of the basic features of its resonant scattering behavior are covered. First, a general physical picture is described by a full electrodynamic perspective, the Lorenz–Mie theory. The resonant spectrum of a dielectric sphere reveals the existence of two distinctive types of polarization enhancement: the plasmonic and the dielectric resonances. The corresponding electrostatic (Rayleigh) picture is analyzed and the polarizability of a homogeneous spherical inclusion is extracted. This description facilitates the identification of the first type of resonance, i.e., the localized surface plasmon (plasmonic) resonance, as a function of the permittivity. Moreover, the electrostatic picture is linked with the plasmon hybridization model through the case of a step-inhomogeneous structure, i.e., a core–shell sphere. The connections between the electrostatic and electrodynamic models are reviewed in the small size limit and details on size-induced aspects, such as the dynamic depolarization and the radiation reaction on a small sphere are exposed through the newly introduced Mie–Padé approximative perspective. The applicability of this approximation is further expanded including the second type of resonances, i.e., the dielectric resonances. For this type of resonances, the Mie–Padé approximation reveals the main character of the two different cases of resonances of either magnetic or electric origin. A unified picture is therefore described encompassing both plasmonic and dielectric resonances, and the resonant conditions of all three different types are extracted as functions of the permittivity and the size of the sphere. Lastly, the directional scattering behavior of the first two dielectric resonances is exposed in a simple manner, namely the Kerker conditions for maximum forward and backscattering between the first magnetic and electric dipole contributions of a dielectric sphere. The presented results address several prominent functional features, aiming at readers with either theoretical or applied interest for the scattering aspects of a resonant sphere. Full article

(This article belongs to the Special Issue Nanophotonics)

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31 pages, 10040 KiB

Open AccessReview

Soliton Molecules and Multisoliton States in Ultrafast Fibre Lasers: Intrinsic Complexes in Dissipative Systems

by Lili Gui^1,*, Pan Wang², Yihang Ding², Kangjun Zhao², Chengying Bao³, Xiaosheng Xiao² and Changxi Yang^2,*

¹ 4th Physics Institute and Research Center SCoPE, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany

² State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing 100084, China

³ Watson Laboratory of Applied Physics, California Institute of Technology, Pasadena, CA 91125, USA

Appl. Sci. 2018, 8(2), 201; https://doi.org/10.3390/app8020201 - 29 Jan 2018

Cited by 88 | Viewed by 8431

Abstract

Benefiting from ultrafast temporal resolution, broadband spectral bandwidth, as well as high peak power, passively mode-locked fibre lasers have attracted growing interest and exhibited great potential from fundamental sciences to industrial and military applications. As a nonlinear system containing complex interactions from gain, [...] Read more.

Benefiting from ultrafast temporal resolution, broadband spectral bandwidth, as well as high peak power, passively mode-locked fibre lasers have attracted growing interest and exhibited great potential from fundamental sciences to industrial and military applications. As a nonlinear system containing complex interactions from gain, loss, nonlinearity, dispersion, etc., ultrafast fibre lasers deliver not only conventional single soliton but also soliton bunching with different types. In analogy to molecules consisting of several atoms in chemistry, soliton molecules (in other words, bound solitons) in fibre lasers are of vital importance for in-depth understanding of the nonlinear interaction mechanism and further exploration for high-capacity fibre-optic communications. In this Review, we summarize the state-of-the-art advances on soliton molecules in ultrafast fibre lasers. A variety of soliton molecules with different numbers of soliton, phase-differences and pulse separations were experimentally observed owing to the flexibility of parameters such as mode-locking techniques and dispersion control. Numerical simulations clearly unravel how different nonlinear interactions contribute to formation of soliton molecules. Analysis of the stability and the underlying physical mechanisms of bound solitons bring important insights to this field. For a complete view of nonlinear optical phenomena in fibre lasers, other dissipative states such as vibrating soliton pairs, soliton rains, rogue waves and coexisting dissipative solitons are also discussed. With development of advanced real-time detection techniques, the internal motion of different pulsing states is anticipated to be characterized, rendering fibre lasers a versatile platform for nonlinear complex dynamics and various practical applications. Full article

(This article belongs to the Section Optics and Lasers)

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13 pages, 1613 KiB

Open AccessReview

High-Power, Solid-State, Deep Ultraviolet Laser Generation

by Hongwen Xuan^1,*, Hironori Igarashi², Shinji Ito¹, Chen Qu², Zhigang Zhao¹ and Yohei Kobayashi¹

¹ The Institute for Solid State Physics, the University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8581, Japan

² GIGAPHOTON INC., 400 Yokokurashinden, Oyama, Tochigi 323-8558, Japan

Appl. Sci. 2018, 8(2), 233; https://doi.org/10.3390/app8020233 - 3 Feb 2018

Cited by 41 | Viewed by 10861

Abstract

At present, deep ultraviolet (DUV) lasers at the wavelength of fourth harmonics of 1 μm (266 nm/258 nm) and at the wavelength of 193 nm are widely utilized in science and industry. We review the generation of these DUV lasers by nonlinear frequency [...] Read more.

At present, deep ultraviolet (DUV) lasers at the wavelength of fourth harmonics of 1 μm (266 nm/258 nm) and at the wavelength of 193 nm are widely utilized in science and industry. We review the generation of these DUV lasers by nonlinear frequency conversion processes using solid-state/fiber lasers as the fundamental frequency. A DUV laser at 258 nm by fourth harmonics generation (FHG) could achieve an average power of 10 W with a beam quality of M² < 1.5. Moreover, 1 W of average power at 193 nm was obtained by sum-frequency generation (SFG). A new concept of 193-nm DUV laser generation by use of the diamond Raman laser is also introduced. A proof-of-principle experiment of the diamond Raman laser is reported with the conversion efficiency of 23% from the pump to the second Stokes wavelength, which implies the potential to generate a higher power 193 nm DUV laser in the future. Full article

(This article belongs to the Special Issue Solid State Lasers Materials, Technologies and Applications)

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17 pages, 7814 KiB

Open AccessReview

Monitoring and Prediction of Traffic Noise in Large Urban Areas

by Giovanni Zambon¹

, Hector Eduardo Roman², Maura Smiraglia¹ and Roberto Benocci^1,*

¹ Department of Earth and Environmental Sciences (DISAT), University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milano, Italy

² Department of Physics, University of Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy

Appl. Sci. 2018, 8(2), 251; https://doi.org/10.3390/app8020251 - 7 Feb 2018

Cited by 58 | Viewed by 6052

Abstract

Dynamap, a co-financed project by the European Commission through the Life+ 2013 program, aims at developing a dynamic approach for noise mapping that is capable of updating environmental noise levels through a direct link with a limited number of noise monitoring terminals. Dynamap [...] Read more.

Dynamap, a co-financed project by the European Commission through the Life+ 2013 program, aims at developing a dynamic approach for noise mapping that is capable of updating environmental noise levels through a direct link with a limited number of noise monitoring terminals. Dynamap is based on the idea of finding a suitable set of roads that display similar traffic noise behavior (temporal noise profile over an entire day) so that one can group them together into a single noise map. Each map thus represents a group of road stretches whose traffic noise will be updated periodically, typically every five minutes during daily hours and every hour during night. The information regarding traffic noise will be taken continuously from a small number of monitoring stations (typically 24) appropriately distributed over the urban zone of interest. To achieve this goal, we have performed a detailed analysis of traffic noise data, recorded every second from 93 monitoring stations randomly distributed over the entire urban area of the City of Milan. Our results are presented for a restricted area, the urban Zone 9 of Milan. We have separated the entire set of (about 2000) stretches into six groups, each one represented by a noise map, and gave a prescription for the locations of the future 24 monitoring stations. From our analysis, it is estimated that the mean overall error for each group of stretches (noise map), averaged over the 24 h, is about 2 dB. Full article

(This article belongs to the Section Acoustics and Vibrations)

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19 pages, 5622 KiB

Open AccessReview

Metal Carbides for Biomass Valorization

by Carine E. Chan-Thaw^1,* and Alberto Villa^2,*

¹ Institut pour la Maîtrise de l’Énergie, Université d’Antananarivo, BP 566, Antananarivo 101, Madagascar

² Dipartimento di Chimica, Università degli Studi di Milano, via Golgi 19, 20133 Milano, Italy

Appl. Sci. 2018, 8(2), 259; https://doi.org/10.3390/app8020259 - 9 Feb 2018

Cited by 22 | Viewed by 6338

Abstract

Transition metal carbides have been utilized as an alternative catalyst to expensive noble metals for the conversion of biomass. Tungsten and molybdenum carbides have been shown to be effective catalysts for hydrogenation, hydrodeoxygenation and isomerization reactions. The satisfactory activities of these metal carbides [...] Read more.

Transition metal carbides have been utilized as an alternative catalyst to expensive noble metals for the conversion of biomass. Tungsten and molybdenum carbides have been shown to be effective catalysts for hydrogenation, hydrodeoxygenation and isomerization reactions. The satisfactory activities of these metal carbides and their low costs, compared with noble metals, make them appealing alternatives and worthy of further investigation. In this review, we succinctly describe common synthesis techniques, including temperature-programmed reaction and carbothermal hydrogen reduction, utilized to prepare metal carbides used for biomass transformation. Attention will be focused, successively, on the application of transition metal carbide catalysts in the transformation of first-generation (oils) and second-generation (lignocellulose) biomass to biofuels and fine chemicals. Full article

(This article belongs to the Section Chemical and Molecular Sciences)

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12 pages, 935 KiB

Open AccessFeature PaperReview

Riding the Plane Wave: Considerations for In Vivo Study Designs Employing High Frame Rate Ultrasound

by Jason S. Au^1,2

, Richard L. Hughson^2,3 and Alfred C. H. Yu^1,2,*

¹ Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada

² Schlegel-University of Waterloo Research Institute for Aging, Waterloo, ON N2J 0E2, Canada

³ Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada

Appl. Sci. 2018, 8(2), 286; https://doi.org/10.3390/app8020286 - 14 Feb 2018

Cited by 10 | Viewed by 6376

Abstract

Advancements in diagnostic ultrasound have allowed for a rapid expansion of the quantity and quality of non-invasive information that clinical researchers can acquire from cardiovascular physiology. The recent emergence of high frame rate ultrasound (HiFRUS) is the next step in the quantification of [...] Read more.

Advancements in diagnostic ultrasound have allowed for a rapid expansion of the quantity and quality of non-invasive information that clinical researchers can acquire from cardiovascular physiology. The recent emergence of high frame rate ultrasound (HiFRUS) is the next step in the quantification of complex blood flow behavior, offering angle-independent, high temporal resolution data in normal physiology and clinical cases. While there are various HiFRUS methods that have been tested and validated in simulations and in complex flow phantoms, there is a need to expand the field into more rigorous in vivo testing for clinical relevance. In this tutorial, we briefly outline the major advances in HiFRUS, and discuss practical considerations of participant preparation, experimental design, and human measurement, while also providing an example of how these frameworks can be immediately applied to in vivo research questions. The considerations put forward in this paper aim to set a realistic framework for research labs which use HiFRUS to commence the collection of human data for basic science, as well as for preliminary clinical research questions. Full article

(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)

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16 pages, 2249 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Inkjet-Printed and Paper-Based Electrochemical Sensors

by Ryan P. Tortorich¹, Hamed Shamkhalichenar¹ and Jin-Woo Choi^1,2,*

¹ School of Electrical Engineering and Computer Science, Louisiana State University, Baton Rouge, LA 70803, USA

² Center for Advanced Microstructures and Devices, Louisiana State University, Baton Rouge, LA 70803, USA

Appl. Sci. 2018, 8(2), 288; https://doi.org/10.3390/app8020288 - 14 Feb 2018

Cited by 120 | Viewed by 14826

Abstract

It is becoming increasingly more important to provide a low-cost point-of-care diagnostic device with the ability to detect and monitor various biological and chemical compounds. Traditional laboratories can be time-consuming and very costly. Through the combination of well-established materials and fabrication methods, it [...] Read more.

It is becoming increasingly more important to provide a low-cost point-of-care diagnostic device with the ability to detect and monitor various biological and chemical compounds. Traditional laboratories can be time-consuming and very costly. Through the combination of well-established materials and fabrication methods, it is possible to produce devices that meet the needs of many patients, healthcare and medical professionals, and environmental specialists. Existing research has demonstrated that inkjet-printed and paper-based electrochemical sensors are suitable for this application due to advantages provided by the carefully selected materials and fabrication method. Inkjet printing provides a low cost fabrication method with incredible control over the material deposition process, while paper-based substrates enable pump-free microfluidic devices due to their natural wicking ability. Furthermore, electrochemical sensing is incredibly selective and provides accurate and repeatable quantitative results without expensive measurement equipment. By merging each of these favorable techniques and materials and continuing to innovate, the production of low-cost point-of-care sensors is certainly within reach. Full article

(This article belongs to the Special Issue Printed Electronics 2017)

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32 pages, 8530 KiB

Open AccessReview

Emergence of White Organic Light-Emitting Diodes Based on Thermally Activated Delayed Fluorescence

by Peng Xiao¹, Ting Dong², Jianing Xie^1,*, Dongxiang Luo³, Jian Yuan¹ and Baiquan Liu^4,5,*

¹ School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China

² Guangdong Juhua Printed Display Technology Co. Ltd. Guangzhou 510006, China

³ School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China

⁴ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China

⁵ LUMINOUS! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798, Singapore

Appl. Sci. 2018, 8(2), 299; https://doi.org/10.3390/app8020299 - 19 Feb 2018

Cited by 41 | Viewed by 9316

Abstract

Recently, thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) have attracted both academic and industrial interest due to their extraordinary characteristics, such as high efficiency, low driving voltage, bright luminance, lower power consumption and potentially long lifetime. In this invited review, the [...] Read more.

Recently, thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) have attracted both academic and industrial interest due to their extraordinary characteristics, such as high efficiency, low driving voltage, bright luminance, lower power consumption and potentially long lifetime. In this invited review, the fundamental concepts of TADF have been firstly introduced. Then, main approaches to realize WOLEDs based on TADF have been summarized. More specifically, the recent development of WOLEDs based on all TADF emitters, WOLEDs based on TADF and conventional fluorescence emitters, hybrid WOLEDs based on blue TADF and phosphorescence emitters and WOLEDs based on TADF exciplex host and phosphorescence dopants is highlighted. In particular, design strategies, device structures, working mechanisms and electroluminescent processes of the representative WOLEDs based on TADF are reviewed. Finally, challenges and opportunities for further enhancement of the performance of WOLEDs based on TADF are presented. Full article

(This article belongs to the Special Issue Fluorescence and Phosphorescence in Organic Materials: from Fundamental to OLED Devices)

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20 pages, 7562 KiB

Open AccessReview

Evaluation of Low-Temperature Cracking Performance of Asphalt Pavements Using Acoustic Emission: A Review

by Behzad Behnia¹, William Buttlar² and Henrique Reis^3,*

¹ Department of Civil and Environmental Engineering, Clarkson University, Potsdam, NY 13699, USA

² Department of Civil and Environmental Engineering, University of Missouri, Columbia, MO 65211, USA

³ Department of Industrial and Enterprise Systems Engineering, University of Illinois, Urbana, IL 61801, USA

Appl. Sci. 2018, 8(2), 306; https://doi.org/10.3390/app8020306 - 21 Feb 2018

Cited by 47 | Viewed by 8965

Abstract

Low-temperature cracking is a major form of distress that can compromise the structural integrity of asphalt pavements located in cold regions. A review of an Acoustic Emission (AE)-based approach is presented that is capable of assessing the low-temperature cracking performance of asphalt binders [...] Read more.

Low-temperature cracking is a major form of distress that can compromise the structural integrity of asphalt pavements located in cold regions. A review of an Acoustic Emission (AE)-based approach is presented that is capable of assessing the low-temperature cracking performance of asphalt binders and asphalt pavement materials through determining their embrittlement temperatures. A review of the background and fundamental aspects of the AE-based approach with a brief overview of its application to estimate low-temperature performance of unaged, short-term, and long-term aged binders, as well as asphalt materials, is presented. The application of asphalt pavements containing recycled asphalt pavement (RAP) and recycled asphalt shingles (RAS) materials to thermal cracking assessment is also presented and discussed. Using the Felicity effect, the approach is capable of evaluating the self-healing characteristics of asphalt pavements and the effect of cooling cycles upon their fracture behavior. Using an iterative AE source location technique, the approach is also used to evaluate the efficiency of rejuvenators, which can restore aged asphalt pavements to their original crack-resistant state. Results indicate that AE allows for relatively rapid and inexpensive characterization of pavement materials and can be used towards enhancing pavement sustainability and resiliency to thermal loading. Full article

(This article belongs to the Special Issue Structural Health Monitoring of Large Structures Using Acoustic Emission–Case Histories)

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