Applied Sciences

Editorial

3 pages, 149 KiB

Open AccessEditorial

Editorial for Special Issue: “Heat Transfer Processes in Oscillatory Flow Conditions”

by Artur J. Jaworski

Chair in Energy Technology and Environment, Faculty of Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK

Appl. Sci. 2017, 7(10), 994; https://doi.org/10.3390/app7100994 - 26 Sep 2017

Cited by 4 | Viewed by 3253

Abstract

Heat exchange processes in steady flows have been studied extensively over the last two hundred years, and are now part of undergraduate syllabi of most engineering courses [...]
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(This article belongs to the Special Issue Heat Transfer Processes in Oscillatory Flow Conditions)

5 pages, 198 KiB

Open AccessEditorial

Imagining the Future of the Internal Combustion Engine for Ground Transport in the Current Context

by José Ramón Serrano

CMT-Motores Térmicos, Universitat Politècnica de València, Camino de Vera, s/n 46022 Valencia, Spain

Appl. Sci. 2017, 7(10), 1001; https://doi.org/10.3390/app7101001 - 28 Sep 2017

Cited by 38 | Viewed by 6555

Abstract

Internal Combustion Engines (ICEs) are the main propulsion systems for ground transport, both in on-road and off-road applications [...]
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(This article belongs to the Special Issue Internal Combustion Engines (ICE) for Ground Transport)

3 pages, 152 KiB

Open AccessEditorial

Special Feature Development and Application of Optical Coherence Tomography (OCT)

by Michael Pircher

Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringerguertel 18-20, 1090 Vienna, Austria

Appl. Sci. 2017, 7(10), 1507; https://doi.org/10.3390/app7101507 - 13 Oct 2017

Viewed by 2976

Abstract

To celebrate the 25th anniversary of the introduction of OCT, the special feature issue entitled “Development and Application of Optical Coherence Tomography (OCT)” had been initiated [...]
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(This article belongs to the Special Issue Development and Application of Optical Coherence Tomography (OCT))

Research

Jump to: Editorial, Review, Other

16 pages, 607 KiB

Open AccessArticle

Indistinguishability Operators Applied to Task Allocation Problems in Multi-Agent Systems

by José Guerrero^*

, Juan-José Miñana

, Oscar Valero

and Gabriel Oliver

Department of Mathematics and Computer Science, University of the Balearic Islands, Ctra. de Valldemossa Km. 7.5, 07122 Palma, Baleares, Spain

Appl. Sci. 2017, 7(10), 963; https://doi.org/10.3390/app7100963 - 21 Sep 2017

Cited by 10 | Viewed by 3894

Abstract

In this paper we show an application of indistinguishability operators to model response functions. Such functions are used in the mathematical modeling of the task allocation problem in multi-agent systems when the stimulus, perceived by the agent, to perform a task is assessed [...] Read more.

In this paper we show an application of indistinguishability operators to model response functions. Such functions are used in the mathematical modeling of the task allocation problem in multi-agent systems when the stimulus, perceived by the agent, to perform a task is assessed by means of the response threshold model. In particular, we propose this kind of operators to represent a response function when the stimulus only depends on the distance between the agent and a determined task, since we prove that two celebrated response functions used in the literature can be reproduced by appropriate indistinguishability operators when the stimulus only depends on the distance to each task that must be carried out. Despite the fact there is currently no systematic method to generate response functions, this paper provides, for the first time, a theoretical foundation to generate them and study their properties. To validate the theoretical results, the aforementioned indistinguishability operators have been used to simulate, with MATLAB, the allocation of a set of tasks in a multi-robot system with fuzzy Markov chains. Full article

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32 pages, 18696 KiB

Open AccessArticle

Bar-Wave Calibration of Acoustic Emission Sensors

by Kanji Ono^1,*

, Takahiro Hayashi²

and Hideo Cho³

¹ Department of Materials Science and Engineering, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA

² Department of Aeronautics and Astronautics, Kyoto University, Nishikyo, Kyoto 615-8540, Japan

³ Department of Mechanical Engineering, Aoyama Gakuin University, Fuchinobe, Chuo, Sagamihara 252-5258, Japan

Appl. Sci. 2017, 7(10), 964; https://doi.org/10.3390/app7100964 - 21 Sep 2017

Cited by 11 | Viewed by 4833

Abstract

This study extended a bar-wave calibration method for acoustic emission (AE) sensors. It combined laser interferometer displacement measurements and the wave propagation medium of a long bar, excited at its end with an ultrasonic transducer driven by a pulser. Receiving bar-wave sensitivities of [...] Read more.

This study extended a bar-wave calibration method for acoustic emission (AE) sensors. It combined laser interferometer displacement measurements and the wave propagation medium of a long bar, excited at its end with an ultrasonic transducer driven by a pulser. Receiving bar-wave sensitivities of 16 types of AE sensors were measured and compared to their receiving sensitivities to normally incident waves. The two types of the receiving sensitivity always differed for a given AE sensor. The bar-wave sensitivities of R6a sensors resembled their surface-wave sensitivities, indicating that the bar-wave sensitivities can represent the surface-wave sensitivities in typical AE applications. Some bar-wave modes were identified by comparing peaks found on observed Choi-Williams transform spectrograms with the positions on the dispersion curves for bar waves, calculated with the SAFE procedure. However, numerous bar-wave modes prevented exact identification, especially above 500 kHz. Aperture effects contributed to the sensitivity reduction at higher frequencies and to more fluctuating bar-wave receiving sensitivities even for sensors with smooth or flat receiving sensitivities to normally incident waves. Spectral dips observed in bar-wave results can be accounted for by aperture effect predictions reasonably well. For the selection of AE sensors, one needs to use the appropriate type of sensitivities considering waves to be detected. Full article

(This article belongs to the Section Acoustics and Vibrations)

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11 pages, 2208 KiB

Open AccessArticle

Registration of Urban Aerial Image and LiDAR Based on Line Vectors

by Qinghong Sheng^1,*, Qi Wang¹, Xinyue Zhang¹, Bo Wang¹, Bin Zhang¹ and Zhengning Zhang²

¹ College of Astronautics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China

² Tianjin Key Laboratory of Intelligent Information Processing in Remote Sensing, Tianjin 300301, China

Appl. Sci. 2017, 7(10), 965; https://doi.org/10.3390/app7100965 - 21 Sep 2017

Cited by 8 | Viewed by 3902

Abstract

In a traditional registration of a single aerial image with airborne light detection and ranging (LiDAR) data using linear features that regard line direction as a control or linear features as constraints in the solution, lacking the constraint of linear position leads to [...] Read more.

In a traditional registration of a single aerial image with airborne light detection and ranging (LiDAR) data using linear features that regard line direction as a control or linear features as constraints in the solution, lacking the constraint of linear position leads to the error propagation of the adjustment model. To solve this problem, this paper presents a line vector-based registration mode (LVR) in which image rays and LiDAR lines are expressed by a line vector that integrates the line direction and the line position. A registration equation of line vector is set up by coplanar imaging rays and corresponding control lines. Three types of datasets consisting of synthetic, theInternational Society for Photogrammetry and Remote Sensing (ISPRS) test project, and real aerial data are used. A group of progressive experiments is undertaken to evaluate the robustness of the LVR. Experimental results demonstrate that the integrated line direction and the line position contributes a great deal to the theoretical and real accuracies of the unknowns, as well as the stability of the adjustment model. This paper provides a new suggestion that, for a single image and LiDAR data, registration in urban areas can be accomplished by accommodating rich line features. Full article

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24 pages, 2342 KiB

Open AccessArticle

A Hospital Recommendation System Based on Patient Satisfaction Survey

by Mohammad Reza Khoie^1,*,†, Tannaz Sattari Tabrizi^1,*,†, Elham Sahebkar Khorasani², Shahram Rahimi¹ and Nina Marhamati¹

¹ Department of Computer Science, Southern Illinois University, Carbondale, IL 62901, USA

² Department of Computer Science, University of Illinois at Springfield, Springfield, IL 62703, USA

^† These authors contributed equally to this work.

Appl. Sci. 2017, 7(10), 966; https://doi.org/10.3390/app7100966 - 21 Sep 2017

Cited by 25 | Viewed by 9675

Abstract

Surveys are used by hospitals to evaluate patient satisfaction and to improve general hospital operations. Collected satisfaction data is usually represented to the hospital administration by using statistical charts and graphs. Although such visualization is helpful, typically no deeper data analysis is performed [...] Read more.

Surveys are used by hospitals to evaluate patient satisfaction and to improve general hospital operations. Collected satisfaction data is usually represented to the hospital administration by using statistical charts and graphs. Although such visualization is helpful, typically no deeper data analysis is performed to identify important factors which contribute to patient satisfaction. This work presents an unsupervised data-driven methodology for analyzing patient satisfaction survey data. The goal of the proposed exploratory data analysis is to identify patient communities with similar satisfaction levels and the major factors, which contribute to their satisfaction. This type of data analysis will help hospitals to pinpoint the prevalence of certain satisfaction factors in specific patient communities or clusters of individuals and to implement more proactive measures to improve patient experience and care. To this end, two layers of data analysis is performed. In the first layer, patients are clustered based on their responses to the survey questions. Each cluster is then labeled according to its salient features. In the second layer, the clusters of first layer are divided into sub-clusters based on patient demographic data. Associations are derived between the salient features of each cluster and its sub-clusters. Such associations are ranked and validated by using standard statistical tests. The associations derived by this methodology are turned into comments and recommendations for healthcare providers and patients. Having applied this method on patient and survey data of a hospital resulted in 19 recommendations where 10 of them were statistically significant with chi-square test’s p-value less than 0.5 and an odds ratio z-test’s p-value of more than 2 or less than −2. These associations not only are statistically significant but seems rational too. Full article

(This article belongs to the Special Issue Smart Healthcare)

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21 pages, 2386 KiB

Open AccessArticle

Computational and Experimental Study on Molecular Structure of Benzo[g]pyrimido[4,5-b]quinoline Derivatives: Preference of Linear over the Angular Isomer

by Jorge Trilleras^1,*

, Dency José Pacheco¹, Alfredo Pérez-Gamboa¹, Jairo Quiroga²

, Alejandro Ortiz², Jaime Gálvez³, Manuel Nogueras⁴

and Justo Cobo⁴

¹ Grupo/Semillero de Investigación en Compuestos Heterocíclicos, Programa de Química, Facultad de Ciencias Básicas, Universidad del Atlántico, Puerto Colombia, Atlántico, Colombia

² Grupo de Investigación de Compuestos Heterocíclicos, Departamento de Química, Universidad del Valle, A. A 25360, Cali, Colombia

³ Centro Nacional de Asistencia Técnica a la Industria (Centro—ASTIN)—SENA, Complejo Salomia, Cali, Colombia

⁴ Departamento de Química Inorgánica y Orgánica, Universidad de Jaén, 23071 Jaén, Spain

Appl. Sci. 2017, 7(10), 967; https://doi.org/10.3390/app7100967 - 21 Sep 2017

Cited by 6 | Viewed by 5568

Abstract

A series of 5-aryl-2-methylthio-5,12-dihydrobenzo[g]pyrimido[4,5-b]quinoline-4,6,11(3H)-trione was synthesized through an environmental friendly multicomponent methodology and characterized with FT-IR (Fourier Transform infrared spectroscopy), ¹H NMR (Nuclear Magnetic Resonance ), ¹³C NMR and GC-MS (gas chromatography-mass spectrometry). The 5-(4-methoxyphenyl)-2-methylthio-5,12-dihydrobenzo[ [...] Read more.

A series of 5-aryl-2-methylthio-5,12-dihydrobenzo[g]pyrimido[4,5-b]quinoline-4,6,11(3H)-trione was synthesized through an environmental friendly multicomponent methodology and characterized with FT-IR (Fourier Transform infrared spectroscopy), ¹H NMR (Nuclear Magnetic Resonance ), ¹³C NMR and GC-MS (gas chromatography-mass spectrometry). The 5-(4-methoxyphenyl)-2-methylthio-5,12-dihydrobenzo[g]pyrimido[4,5-b]quinoline-4,6,11(3H)-trione 4c compound was characterized by X-ray single crystal diffraction. The geometry of 4c has been fully optimized using DFT (Density functional theory), B3LYP functional and 6-31G(d,p) basis set, thus establishing the ground state energy and thermodynamic features for the mentioned compound, which are in accordance with the experimental data and the crystal structure. The experimental results reveal a strong preference for the regioselective formation of 4c linear four fused rings over the angular four fused and suggest a possible kinetic control in product formation. Full article

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

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15 pages, 3179 KiB

Open AccessArticle

Application of Deep Networks to Oil Spill Detection Using Polarimetric Synthetic Aperture Radar Images

by Guandong Chen¹, Yu Li^1,*, Guangmin Sun¹ and Yuanzhi Zhang^2,3,*

¹ Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China

² National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China

³ Key Laboratory of Lunar Science and Deep-space Exploration, Chinese Academy of Sciences, Beijing 100012, China

Appl. Sci. 2017, 7(10), 968; https://doi.org/10.3390/app7100968 - 21 Sep 2017

Cited by 78 | Viewed by 7093

Abstract

Polarimetric synthetic aperture radar (SAR) remote sensing provides an outstanding tool in oil spill detection and classification, for its advantages in distinguishing mineral oil and biogenic lookalikes. Various features can be extracted from polarimetric SAR data. The large number and correlated nature of [...] Read more.

Polarimetric synthetic aperture radar (SAR) remote sensing provides an outstanding tool in oil spill detection and classification, for its advantages in distinguishing mineral oil and biogenic lookalikes. Various features can be extracted from polarimetric SAR data. The large number and correlated nature of polarimetric SAR features make the selection and optimization of these features impact on the performance of oil spill classification algorithms. In this paper, deep learning algorithms such as the stacked autoencoder (SAE) and deep belief network (DBN) are applied to optimize the polarimetric feature sets and reduce the feature dimension through layer-wise unsupervised pre-training. An experiment was conducted on RADARSAT-2 quad-polarimetric SAR image acquired during the Norwegian oil-on-water exercise of 2011, in which verified mineral, emulsions, and biogenic slicks were analyzed. The results show that oil spill classification achieved by deep networks outperformed both support vector machine (SVM) and traditional artificial neural networks (ANN) with similar parameter settings, especially when the number of training data samples is limited. Full article

(This article belongs to the Special Issue Application of Artificial Neural Networks in Geoinformatics)

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13 pages, 3898 KiB

Open AccessArticle

A Precise Positioning Method for a Puncture Robot Based on a PSO-Optimized BP Neural Network Algorithm

by Guanwu Jiang^1,2,3,4,*, Minzhou Luo^1,2,4,*, Keqiang Bai^1,3,* and Saixuan Chen^1,2,4

¹ The Department of Automation, University of Science and Technology of China, Hefei 230026, China

² Key Laboratory of Special Robot Technology of Jiangsu Province, Hohai University, Changzhou 213000, China

³ School of Information Engineering, Southwest University of Science and Technology, Mianyang 621010, China

⁴ Institute of Intelligent Manufacturing Technology, Jiangsu Industrial Technology Research Institute, Nanjing 211800, China

Appl. Sci. 2017, 7(10), 969; https://doi.org/10.3390/app7100969 - 21 Sep 2017

Cited by 81 | Viewed by 8474

Abstract

The problem of inverse kinematics is fundamental in robot control. Many traditional inverse kinematics solutions, such as geometry, iteration, and algebraic methods, are inadequate in high-speed solutions and accurate positioning. In recent years, the problem of robot inverse kinematics based on neural networks [...] Read more.

The problem of inverse kinematics is fundamental in robot control. Many traditional inverse kinematics solutions, such as geometry, iteration, and algebraic methods, are inadequate in high-speed solutions and accurate positioning. In recent years, the problem of robot inverse kinematics based on neural networks has received extensive attention, but its precision control is convenient and needs to be improved. This paper studies a particle swarm optimization (PSO) back propagation (BP) neural network algorithm to solve the inverse kinematics problem of a UR3 robot based on six degrees of freedom, overcoming some disadvantages of BP neural networks. The BP neural network improves the convergence precision, convergence speed, and generalization ability. The results show that the position error is solved by the research method with respect to the UR3 robot inverse kinematics with the joint angle less than 0.1 degrees and the output end tool less than 0.1 mm, achieving the required positioning for medical puncture surgery, which demands precise positioning of the robot to less than 1 mm. Aiming at the precise application of the puncturing robot, the preliminary experiment has been conducted and the preliminary results have been obtained, which lays the foundation for the popularization of the robot in the medical field. Full article

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

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32 pages, 1163 KiB

Open AccessArticle

Supporting an Object-Oriented Approach to Unit Generator Development: The Csound Plugin Opcode Framework

by Victor Lazzarini

Music Department, Maynooth University, Maynooth W23 X021, Ireland

Appl. Sci. 2017, 7(10), 970; https://doi.org/10.3390/app7100970 - 21 Sep 2017

Cited by 5 | Viewed by 5333

Abstract

This article presents a new framework for unit generator development for Csound, supporting a full object-oriented programming approach. It introduces the concept of unit generators and opcodes, and its centrality with regards to music programming languages in general, and Csound in specific. The [...] Read more.

This article presents a new framework for unit generator development for Csound, supporting a full object-oriented programming approach. It introduces the concept of unit generators and opcodes, and its centrality with regards to music programming languages in general, and Csound in specific. The layout of an opcode from the perspective of the Csound C-language API is presented, with some outline code examples. This is followed by a discussion which places the unit generator within the object-oriented paradigm and the motivation for a full C++ programming support, which is provided by the Csound Plugin Opcode Framework (CPOF). The design of CPOF is then explored in detail, supported by several opcode examples. The article concludes by discussing two key applications of object-orientation and their respective instances in the Csound code base. Full article

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

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14 pages, 3863 KiB

Open AccessArticle

A Comparison Study for Chloride-Binding Capacity between Alkali-Activated Fly Ash and Slag in the Use of Seawater

by Yubin Jun¹

, Seyoon Yoon^2,*

and Jae Eun Oh^1,*

¹ School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea

² Department of Civil Engineering, Kyonggi University, Suwon 16227, Korea

Appl. Sci. 2017, 7(10), 971; https://doi.org/10.3390/app7100971 - 22 Sep 2017

Cited by 60 | Viewed by 5622

Abstract

This study aimed to investigate the chloride-binding capacity of alkali-activated fly ash (denoted as FSW) and slag (denoted as SSW) samples and their synthesized Cl-bearing phases, which are capable of binding and immobilizing chloride when seawater is used as the mixing water. This [...] Read more.

This study aimed to investigate the chloride-binding capacity of alkali-activated fly ash (denoted as FSW) and slag (denoted as SSW) samples and their synthesized Cl-bearing phases, which are capable of binding and immobilizing chloride when seawater is used as the mixing water. This study also examined the progressive changes in the pore structures of the FSW and SSW samples over time. The results show that the SSW sample is significantly more effective in the uptake of chloride ions compared to the FSW sample at 28 days of curing. While the FSW sample forms Cl-bearing zeolites (Cl-chabazite and Cl-sodalite) (possibly with similar types of geopolymeric gels), the SSW sample synthesizes Cl-bearing, layered double hydroxides (LDH) (Cl-hydrocalumite and Cl-hydrotalcite). Although both samples involve Cl-binding phases, the FSW sample is likely to be less efficient because it largely produces zeolites (or similar geopolymeric gels) with no Cl-binding capability (i.e., zeolites X and Y). Meanwhile, the SSW sample produces Cl-bearing LDH phases as well as C-S-H(I), which can physically adsorb chloride. The SSW sample exhibits both pore-size refinement and porosity reduction over time, while the FSW sample only exhibits pore-size refinement. Therefore, the SSW system is more advantageous in the use of seawater because it more effectively prevents Cl ingression due to greater impermeability. Full article

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

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11 pages, 4887 KiB

Open AccessArticle

Enhanced Design of a Soft Thin-Film Vibrotactile Actuator Based on PVC Gel

by Won-Hyeong Park, Eun-Jae Shin and Sang-Youn Kim^*

Interaction Laboratory, Advanced Research Technology Center, Korea University of Technology and Education, Chungjeol-ro, Byeongcheon-myeon, Dongnam-gu, Cheonan 330-708, ChungNam, Korea

Appl. Sci. 2017, 7(10), 972; https://doi.org/10.3390/app7100972 - 22 Sep 2017

Cited by 12 | Viewed by 6733

Abstract

We fabricated a soft thin-film vibrotactile actuator, which can be easily inserted into wearable devices, based on an electroactive PVC gel. One of the most important factors in fabricating a soft and thin vibrotactile actuator is to create vibrational force strong enough to [...] Read more.

We fabricated a soft thin-film vibrotactile actuator, which can be easily inserted into wearable devices, based on an electroactive PVC gel. One of the most important factors in fabricating a soft and thin vibrotactile actuator is to create vibrational force strong enough to stimulate human skin in a wide frequency range. To achieve this, we investigate the working principle of the PVC gel and suggest a new structure in which most of electric energy contributes to the deformation of the PVC gel. Due to this structure, the vibrational amplitude of the proposed PVC gel actuator could considerably increase (0.816 g (g = 9.8 m/s²) at resonant frequency). The vibrotactile amplitude is proportional to the amount of input voltage. It increased from 0.05 g up to 0.416 g with increasing applied voltages from 200 V to 1 kV at 1 Hz. The experimental results show that the proposed actuator can create a variety of haptic sensations. Full article

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

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Graphical abstract

9 pages, 1751 KiB

Open AccessArticle

Multivariate Analysis of Laser-Induced Tissue Ablation: Ex Vivo Liver Testing

by Suhyun Park¹ and Hyun Wook Kang^2,*

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

² Department of Biomedical Engineering and Center for Marine-Integrated Biomedical Technology (BK 21 Plus), Pukyong National University, Busan 48513, Korea

Appl. Sci. 2017, 7(10), 974; https://doi.org/10.3390/app7100974 - 22 Sep 2017

Cited by 5 | Viewed by 4035

Abstract

A number of laser parameters are often regulated to enhance ablation efficiency during laser surgery. As one of clinical treatments, laser removal of benign prostate hyperplasia has been well accepted by surgical urologists. However, due to complex interactions of the surgical parameters, the [...] Read more.

A number of laser parameters are often regulated to enhance ablation efficiency during laser surgery. As one of clinical treatments, laser removal of benign prostate hyperplasia has been well accepted by surgical urologists. However, due to complex interactions of the surgical parameters, the procedure is still lengthy and dependent upon the surgeon’s skill and experience. The aim of the current study is to evaluate the feasibility of response surface method (RSM) to comprehend ablative interactions of multi-parameters and to identify the optimal ablation rate (AR). As a surrogate model in the feasibility study, bovine liver tissue was utilized for ex vivo ablation testing. Three laser parameters pertinent to laser prostatectomy were selected: power (P), treatment speed (TS), and beam spot (BS). As a three-level fractional factorial RSM, Box Behnken design (BBD) was employed to identify the range of each parameter for achieving the optimal AR. The results showed that regardless of TS, AR was linearly contingent on both P and BS due to high irradiance. TS of 6~7 mm/s induced the maximal AR when P of 180 W and BS of 0.4 mm². The corresponding volumetric density energy yielded an ablation volume of 80 mm², which was close to a transition to volumetric saturation. The BBD-based model showed a good agreement with the experimental data in terms of ablation volume. The proposed multivariate parametric analysis can be an efficient design method to identify the optimal conditions for laser therapeutics. Further investigations will be performed on prostatic tissue to validate the proposed approach and to explore various optimization processes. Full article

(This article belongs to the Section Optics and Lasers)

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16 pages, 3820 KiB

Open AccessArticle

Assessing the Performance of Thermal Inertia and Hydrus Models to Estimate Surface Soil Water Content

by Amro Negm^1,2

, Fulvio Capodici³

, Giuseppe Ciraolo³

, Antonino Maltese³

, Giuseppe Provenzano¹

and Giovanni Rallo^4,*

¹ Dipartimento Scienze Agrarie, Alimentari e Forestali, Università degli Studi di Palermo, Viale delle Scienze Bld. 4, 90128 Palermo, Italy

² Department of Geoscience (Earth Sciences), University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada

³ Dipartimento Ingegneria Civile, Ambientale, Aerospaziale e dei Materiali, Università degli Studi di Palermo, Viale delle Scienze Bld. 8, 90128 Palermo, Italy

⁴ Dipartimento Scienze Agrarie, Alimentari e Agro-Ambientali, Università di Pisa, Via del Borghetto 80, 56124 Pisa, Italy

Appl. Sci. 2017, 7(10), 975; https://doi.org/10.3390/app7100975 - 22 Sep 2017

Cited by 15 | Viewed by 4382

Abstract

The knowledge of soil water content (SWC) dynamics in the upper soil layer is important for several hydrological processes. Due to the difficulty of assessing the spatial and temporal SWC dynamics in the field, some model-based approaches have been proposed during the last [...] Read more.

The knowledge of soil water content (SWC) dynamics in the upper soil layer is important for several hydrological processes. Due to the difficulty of assessing the spatial and temporal SWC dynamics in the field, some model-based approaches have been proposed during the last decade. The main objective of this work was to assess the performance of two approaches to estimate SWC in the upper soil layer under field conditions: the physically-based thermal inertia and the Hydrus model. Their validity was firstly assessed under controlled laboratory conditions. Thermal inertia was firstly validated in laboratory conditions using the transient line heat source (TLHS) method. Then, it was applied in situ to analyze the dynamics of soil thermal properties under two extreme conditions of soil-water status (well-watered and air-dry), using proximity remote-sensed data. The model performance was assessed using sensor-based measurements of soil water content acquired through frequency (FDR) and time domain reflectometry (TDR). During the laboratory experiment, the Root Mean Square Error (RMSE) was 0.02 m³ m⁻³ for the Hydrus model and 0.05 m³ m⁻³ for the TLHS model approach. On the other hand, during the in situ experiment, the temporal variability of SWCs simulated by the Hydrus model and the corresponding values measured by the TDR method evidenced good agreement (RMSE ranging between 0.01 and 0.005 m³ m⁻³). Similarly, the average of the SWCs derived from the thermal diffusion model was fairly close to those estimated by Hydrus (spatially averaged RMSE ranging between 0.03 and 0.02 m³ m⁻³). Full article

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13 pages, 5202 KiB

Open AccessArticle

New Chaotic Dynamical System with a Conic-Shaped Equilibrium Located on the Plane Structure

by Jiri Petrzela^*

and Tomas Gotthans

Department of Radio Electronics, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 3082/12, Brno 61600, Czech Republic

Appl. Sci. 2017, 7(10), 976; https://doi.org/10.3390/app7100976 - 22 Sep 2017

Cited by 25 | Viewed by 6543

Abstract

This paper presents a new autonomous deterministic dynamical system with equilibrium degenerated into a plane-oriented hyperbolic geometrical structure. It is demonstrated via numerical analysis and laboratory experiments that the discovered system has both a structurally stable strange attractor and experimentally measurable chaotic behavior. [...] Read more.

This paper presents a new autonomous deterministic dynamical system with equilibrium degenerated into a plane-oriented hyperbolic geometrical structure. It is demonstrated via numerical analysis and laboratory experiments that the discovered system has both a structurally stable strange attractor and experimentally measurable chaotic behavior. It is shown that the evolution of complex dynamics can be associated with a single parameter of a mathematical model and, due to one-to-one correspondence, to a single circuit parameter. Two-dimensional high resolution plots of the largest Lyapunov exponent and basins of attraction expressed in terms of final state energy are calculated and put into the context of the discovered third-order mathematical model and real chaotic oscillator. Both voltage- and current-mode analog chaotic oscillators are presented and verified by visualization of the typical chaotic attractor in a different fashion. Full article

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15 pages, 5942 KiB

Open AccessArticle

Film Thickness Estimation for the Oil Applied to the Inner Surface of Slim Tubes

by Jozef Svetlík^1,*

, Ján Buša², Tomáš Brestovič³, Jozef Dobránsky⁴ and Ján Kráľ⁵

¹ Department of Manufacturing Machinery, Faculty of Mechanical Engineering, The Technical University of Kosice, Letná 9, 04001 Košice, Slovakia

² Department of Mathematics and Theoretical Informatics, Faculty of Electrical Engineerings and Informatics, The Technical University of Košice, Němcovej 32, 04001 Košice, Slovakia

³ Department of Energetics Technics, Faculty of Mechanical Engineering, The Technical University of Kosice, Letná 9, 04001 Košice, Slovakia

⁴ Department of Automobile and Manufacturing Technologies, Faculty of Manufacturing Technologies with a Seat in Prešov, The Technical University of Košice, Bayerova 1, 08001 Prešov, Slovakia

⁵ Prototype and Innovation Centre, Faculty of Mechanical Engineering, The Technical University of Kosice, Letná 9, 04001 Košice, Slovakia

Appl. Sci. 2017, 7(10), 977; https://doi.org/10.3390/app7100977 - 22 Sep 2017

Cited by 3 | Viewed by 4352

Abstract

The article deals with the approximation of the results of experimental measurement of coating of the inner surface of slim pipes with special oil, using a dispersion oil fraction. The reason for such treatment of the inner surface of the tubes is the [...] Read more.

The article deals with the approximation of the results of experimental measurement of coating of the inner surface of slim pipes with special oil, using a dispersion oil fraction. The reason for such treatment of the inner surface of the tubes is the anti-corrosion protection or various other requirements. The oil manufacturer prescribes the minimum required layer to guarantee the anti-corrosion protection parameters. Therefore, it is advisable to know the most exact coating parameters for different pipe diameters. The measured results give us an assumption of how much oil is sufficient to coat the inside of a pipe. The main idea lies in the correct estimation of coefficients in the three-parameter exponential dependence. For the initial estimates, Nelder–Mead’s minimization method was used. The condition for meeting the lower estimate of the minimum thickness of the oil layer was determined. Following graphic processing of minimization of individual pipe diameters, in some cases, the coefficients were adjusted manually. The result is that the oil thickness depends on the distance of the investigated point from the beginning of the tube, or on the point of entry of the dispersion oil fraction. Full article

(This article belongs to the Section Mechanical Engineering)

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15 pages, 4457 KiB

Open AccessArticle

CEPP: Perceiving the Emotional State of the User Based on Body Posture

by Suk Kyu Lee¹, Mungyu Bae², Woonghee Lee² and Hwangnam Kim^2,*

¹ LG Electronics Inc., Seoul 06772, Korea

² School of Electrical Engineering, Korea University, Seoul 02841, Korea

Appl. Sci. 2017, 7(10), 978; https://doi.org/10.3390/app7100978 - 22 Sep 2017

Cited by 9 | Viewed by 4492

Abstract

Much research has been conducted in the area of face and gesture recognition in order to classify one’s emotional state. Surprisingly, utilizing computerized algorithms which recognize emotional conditions based on body postures has not yet been systematically developed. In this paper, we propose [...] Read more.

Much research has been conducted in the area of face and gesture recognition in order to classify one’s emotional state. Surprisingly, utilizing computerized algorithms which recognize emotional conditions based on body postures has not yet been systematically developed. In this paper, we propose a novel method, Computerized Emotion Perception based on Posture (CEPP), to determine the emotional state of the user. This method extracts features from body postures and estimates the emotional state by computing a similarity distance. With the proposed algorithm, we will provide new insights into automatically recognizing one’s emotional state. Full article

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9 pages, 1283 KiB

Open AccessArticle

3D-Printed Super-Wideband Spidron Fractal Cube Antenna with Laminated Copper

by Oh Heon Kwon¹, Won Bin Park¹, Sungwoo Lee¹, Jong Min Lee¹, Young Mi Park² and Keum Cheol Hwang^1,*

¹ School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon 440-746, Korea

² Electronic Warfare PMO, Agency for Defense Development, Daejeon 305-600, Korea

Appl. Sci. 2017, 7(10), 979; https://doi.org/10.3390/app7100979 - 22 Sep 2017

Cited by 12 | Viewed by 8320

Abstract

In this paper, a 3D-printed super-wideband (SWB) Spidron fractal cube antenna is proposed. The Spidron fractal configuration is utilized as a self-complementary structure on each face of a 3D frame to attain SWB characteristics. The antenna is excited through a tapered microstrip balun [...] Read more.

In this paper, a 3D-printed super-wideband (SWB) Spidron fractal cube antenna is proposed. The Spidron fractal configuration is utilized as a self-complementary structure on each face of a 3D frame to attain SWB characteristics. The antenna is excited through a tapered microstrip balun for both mode transforming and impedance matching. A prototype of the proposed antenna, including the 3D frame fabricated with the help of a 3D printer and Spidron fractal patches made of copper tape, is experimentally verified. The measured −10 dB reflection ratio bandwidth is 34:1 (0.44–15.38 GHz). The peak gain varies from 3.42 to 9.29 dBi within the operating frequency bandwidth. The measured radiation patterns are nearly omnidirectional at all operating frequency bands. Full article

(This article belongs to the Special Issue 3D Printed Antennas)

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14 pages, 253 KiB

Open AccessArticle

Postharvest Behavior of Bioactive Compounds in Tomato Fruits Treated with Cu Nanoparticles and NaCl Stress

by Alma Delia Hernández-Fuentes¹, Esly Rubisela López-Vargas², José Manuel Pinedo-Espinoza³, Rafael German Campos-Montiel¹, Jesús Valdés-Reyna² and Antonio Juárez-Maldonado^2,*

¹ Instituto de Ciencias Agropecuarias, Universidad Autónoma del Estado de Hidalgo, Av. Universidad km 1, Rancho Universitario, Tulancingo 43600, Hidalgo, México

² Departamento de Botánica, Universidad Autónoma Agraria Antonio Narro, Saltillo 25315, Coahuila, México

³ Unidad Académica de Agronomía, Universidad Autónoma de Zacatecas, Zacatecas 98000, México

Appl. Sci. 2017, 7(10), 980; https://doi.org/10.3390/app7100980 - 23 Sep 2017

Cited by 47 | Viewed by 5642

Abstract

Tomatoes are important for human diet due to their content of bioactive compounds. However, is little known about behavior of these compounds during fruit shelf life. The goal of this research was to evaluate the effects on bioactive compounds of tomato fruits stored [...] Read more.

Tomatoes are important for human diet due to their content of bioactive compounds. However, is little known about behavior of these compounds during fruit shelf life. The goal of this research was to evaluate the effects on bioactive compounds of tomato fruits stored during different times and conditions, obtained from tomato plants developed under conditions of saline stress and with the application of copper nanoparticles. Four treatments were evaluated: foliar spray of copper nanoparticles (250 mg L⁻¹) with or without saline stress, only saline stress, and the absolute control. The results show that application of copper nanoparticles has a positive effect on the accumulation of bioactive compounds such as total phenols, β-carotene, and vitamin C. The saline stress during the development of tomato plants causes a decrease of the bioactive compounds as well as antioxidant capacity in tomato fruits. However, this negative effect can be reduced with the application of copper nanoparticles. The application of copper nanoparticles may be a technique to increase and maintain the content of bioactive compounds in tomato fruits and can be an effective alternative to diminish the negative effects on bioactive compounds caused by saline stress. Full article

(This article belongs to the Section Nanotechnology and Applied Nanosciences)

10 pages, 2656 KiB

Open AccessArticle

Methods for Determination of the Degree of Iron Oxidation in LiFePO₄

by Fyodor Malchik^1,*, Andrey Kurbatov¹

, Alina Galeyeva¹, Duysek Kamysbaev¹ and Alexandru-Horatiu Marincas²

¹ Center of Physical and Chemical Methods of Research and Analysis, al-Farabi Kazakh National University, 71 al-Farabi Ave., Almaty 050040, Kazakhstan

² Babes Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, 400028 Cluj-Napoca, Romania

Appl. Sci. 2017, 7(10), 981; https://doi.org/10.3390/app7100981 - 24 Sep 2017

Cited by 2 | Viewed by 5341

Abstract

The disposal of LiFePO₄ (LFP) cathode material through oxidation in an air atmosphere is explained by its high chemical activity and high surface area (especially for nanoparticles). In this article, new methods for the determination of the degree of iron oxidation in [...] Read more.

The disposal of LiFePO₄ (LFP) cathode material through oxidation in an air atmosphere is explained by its high chemical activity and high surface area (especially for nanoparticles). In this article, new methods for the determination of the degree of iron oxidation in LFP (oxidation degree) are taken into consideration, specifically those which do not require complicated hardware support. The proposed methods are based on electrochemical oxidation (coulometric method) and chemical oxidation (chemical oxidation in alkaline and acidic solutions). As an arbitration method for analyzing the iron state, the method of Mössbauer spectroscopy (being the most proven and reliable method) was chosen. With respect to the proposed methods for determination of the oxidation degree, the most reliable and quick approach is the titrimetric method (oxidation in an acidic medium), which is in good correlation with Mossbauer spectroscopy. The coulometric method is also able to determine the material oxidation degree (with some approximation), but it requires a number of conditions in order to eliminate errors. Full article

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

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17 pages, 10555 KiB

Open AccessArticle

Residual Stress and Deformation Analysis in Butt Welding on 6 mm SUS304 Steel with Jig Constraints Using Gas Metal Arc Welding

by Chi-Liang Kung¹, Cheng-Kuang Hung¹, Chao-Ming Hsu^1,*

and Cheng-Yi Chen^2,*

¹ Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan

² Department of Electrical Engineering, Cheng Shiu University, Kaohsiung 83347, Taiwan

Appl. Sci. 2017, 7(10), 982; https://doi.org/10.3390/app7100982 - 23 Sep 2017

Cited by 13 | Viewed by 6229

Abstract

This article proposes a novel method for analyzing residual stress and deformation in butt welding on 6 mm SUS304 stainless steel plates, using MSC.MARC, a commercial finite element method software, to find the best location for jig fixtures that will minimize welding deformation. [...] Read more.

This article proposes a novel method for analyzing residual stress and deformation in butt welding on 6 mm SUS304 stainless steel plates, using MSC.MARC, a commercial finite element method software, to find the best location for jig fixtures that will minimize welding deformation. Simulation and experimental studies show that a distance of 100 mm between the jig center and the welding bead center is best for inhibiting welding deformation when the jigs experience downward displacement at 0 mm on the steel plate; the total displacement is only about 1.1 mm in the case of a 300 × 250 × 6 mm SUS304 steel plate. In addition, a numerical model shows that four jigs with pitches of 200 mm can better reduce welding deformation than six jigs with pitches of 100 mm. The largest residual stress after welding occurs around the weld bead center, and the residual stress away from the welding bead center increases gradually when jigs have been applied on the steel plate to prevent deformation. The reaction force of the jigs on the steel plate has no further effect in reducing deformation. We conclude that commercially available jigs can inhibit deformation during the welding process. Full article

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

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16 pages, 2912 KiB

Open AccessArticle

A Software Reliability Model with a Weibull Fault Detection Rate Function Subject to Operating Environments

by Kwang Yoon Song¹, In Hong Chang^1,* and Hoang Pham²

¹ Department of Computer Science and Statistics, Chosun University, 309 Pilmun-daero Dong-gu, Gwangju 61452, Korea

² Department of Industrial and Systems Engineering, Rutgers University, 96 Frelinghuysen Road, Piscataway, NJ 08855-8018, USA

Appl. Sci. 2017, 7(10), 983; https://doi.org/10.3390/app7100983 - 25 Sep 2017

Cited by 65 | Viewed by 5520

Abstract

When software systems are introduced, these systems are used in field environments that are the same as or close to those used in the development-testing environments; however, they may also be used in many different locations that may differ from the environment in [...] Read more.

When software systems are introduced, these systems are used in field environments that are the same as or close to those used in the development-testing environments; however, they may also be used in many different locations that may differ from the environment in which they were developed and tested. As such, it is difficult to improve software reliability for a variety of reasons, such as a given environment, or a bug location in code. In this paper, we propose a new software reliability model that takes into account the uncertainty of operating environments. The explicit mean value function solution for the proposed model is presented. Examples are presented to illustrate the goodness of fit of the proposed model and several existing non-homogeneous Poisson process (NHPP) models and confidence intervals of all models based on two sets of failure data collected from software applications. The results show that the proposed model fits the data more closely than other existing NHPP models to a significant extent. Full article

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13 pages, 4189 KiB

Open AccessArticle

Production of Aerated Foamed Concrete with Industrial Waste from the Gems and Jewels Sector of Rio Grande do Sul-Brazil

by Rudimar Pedro¹, Rejane M. C. Tubino¹, Jonas Anversa², Denisar De Col², Richard Thomas Lermen²

and Rodrigo De Almeida Silva^2,*

¹ Laboratory of Environmental Studies for Metallurgy (LEAMet), Post-Graduation Program in Mining, Metallurgical and Materials Engineering (PPGE3M), Department of Engineering, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul 90130-120, Brazil

² Post-Graduation Program in Civil Engineering (PPGEC), Department of Civil Engineering, Polytechnic School, Meridional College (IMED), Passo Fundo, Rio Grande do Sul 99070-220, Brazil

Appl. Sci. 2017, 7(10), 985; https://doi.org/10.3390/app7100985 - 26 Sep 2017

Cited by 13 | Viewed by 7319

Abstract

The use of solid waste for the development of new building materials has been an alternative to reduce environmental impacts through the preservation of natural resources. In this context, this paper evaluates the possibility of using agate gemstone waste, called rolled powder, which [...] Read more.

The use of solid waste for the development of new building materials has been an alternative to reduce environmental impacts through the preservation of natural resources. In this context, this paper evaluates the possibility of using agate gemstone waste, called rolled powder, which basically consists of silica (SiO₂), in the manufacture of aerated foamed concrete blocks completely replacing the natural sand. Preformed foam was used as the air entrained by mechanical stirring with a mixture of natural foaming agents derived from coconut. To produce test specimens, the water/cement ratio and foam concentrations were varied, with three and four levels, respectively. The specimens were left for 28 days at room temperature to be cured, and then underwent analysis to determine their compressive strength, density, and the distribution of air-voids. The experiments demonstrated that the best water/cement ratio was 1.28 for 18% (of total solid mass) addition of foam, which generated a sample with a density of 430 kg/m³, and a compressive strength of 1.07 MPa. The result for compressive strength is 11% smaller than the requirements of the Brazilian standard (NBR 13438) for autoclaved aerated concrete blocks, but the results are promising. Full article

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

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13 pages, 4704 KiB

Open AccessArticle

Experimental Study on Vibration Control of a Submerged Pipeline Model by Eddy Current Tuned Mass Damper

by Wenxi Wang^1,2, Dakota Dalton², Xugang Hua¹, Xiuyong Wang^3,*, Zhengqing Chen¹ and Gangbing Song^2,*

¹ Key Laboratory for Bridge and Wind Engineering of Hunan Province, College of Civil Engineering, Hunan University, Changsha 410082, China

² Department of Mechanical Engineering, University of Houston, Houston, TX 77204, USA

³ College of Civil Engineering, Hunan University of Science and Technology, Xiangtan 411201, China

Appl. Sci. 2017, 7(10), 987; https://doi.org/10.3390/app7100987 - 25 Sep 2017

Cited by 56 | Viewed by 10094

Abstract

Undesirable vibrations occurring in undersea pipeline structures due to ocean currents may shorten the lifecycle of pipeline structures and even lead to their failure. Therefore, it is desirable to find a feasible and effective device to suppress the subsea vibration. Eddy current tuned [...] Read more.

Undesirable vibrations occurring in undersea pipeline structures due to ocean currents may shorten the lifecycle of pipeline structures and even lead to their failure. Therefore, it is desirable to find a feasible and effective device to suppress the subsea vibration. Eddy current tuned mass damper (ECTMD), which employs the damping force generated by the relative movement of a non-magnetic conductive metal (such as copper or aluminum) through a magnetic field, is demonstrated to be an efficient way in structural vibration control. However, the feasibility and effectiveness of ECTMD in a seawater environment has not been reported on before. In this paper, an experiment is conducted to validate the feasibility of an eddy current damper in a seawater environment. A submerged pipeline is used as the controlled structure to experimentally study the effectiveness of ECTMD. The dynamic properties of the submerged pipeline are obtained from dynamic tests and the finite element method (FEM). The optimum design of TMD with a linear spring-damper element for a damped primary structure is carried out through numerical optimization procedures and is used to determine the optimal frequency tuning ratio and damping ratio of ECTMD. In addition, the performance of ECTMD to control the submerged pipeline model is respectively studied in free vibration case and forced vibration case. The results show that the damping provided by eddy current in a seawater environment is only slightly varied compared to that in an air environment. With the optimal ECTMD control, vibration response of the submerged pipeline is significantly decreased. Full article

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

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13 pages, 3694 KiB

Open AccessArticle

A 2D-View Depth Image- and CNN-Based 3D Model Identification Method

by Yiyu Hong¹

and Jongweon Kim^2,*

¹ Department of Copyright Protection, Sangmyung University, Seoul 03016, Korea

² Department of Electronics Engineering, Sangmyung, University, Seoul 03016, Korea

Appl. Sci. 2017, 7(10), 988; https://doi.org/10.3390/app7100988 - 25 Sep 2017

Cited by 2 | Viewed by 5731

Abstract

With the rapid development of three-dimensional (3D) technology and an increase in the number of available models, issues with copyright protection of 3D models are inevitable. In this paper, we propose a 2D-view depth image- and convolutional neural network (CNN)-based 3D model identification [...] Read more.

With the rapid development of three-dimensional (3D) technology and an increase in the number of available models, issues with copyright protection of 3D models are inevitable. In this paper, we propose a 2D-view depth image- and convolutional neural network (CNN)-based 3D model identification method. To identify a 3D model, we first need an adequate number of the modified versions that could be made by copyright infringers. Then, they can be represented by a number of 2D-view depth images that are captured from evenly distributed vertices on a regular convex polyhedron. Finally, a CNN is trained by these depth images to acquire the capability of identifying the 3D model. The experiment carried out with the dataset of Shape Retrieval Contest 2015 (SHREC’15): Non-Rigid 3D Shape Retrieval shows the practicability of our method, which yields 93.5% accuracy. The effectiveness of the proposed method is demonstrated via evaluation in the latest standard benchmark SHREC’17 Deformable Shape Retrieval with Missing Parts. It clearly shows superior or comparable performance to state-of-the-art methods, shown by the fact that it is in the top three of the 11 participating methods (without counting different runs). Full article

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22 pages, 6633 KiB

Open AccessArticle

Robust Background Subtraction via the Local Similarity Statistical Descriptor

by Dongdong Zeng^1,2,*

, Ming Zhu¹, Tongxue Zhou^1,2, Fang Xu^1,2 and Hang Yang¹

¹ Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China

² University of Chinese Academy of Sciences, Beijing 100049, China

Appl. Sci. 2017, 7(10), 989; https://doi.org/10.3390/app7100989 - 25 Sep 2017

Cited by 7 | Viewed by 5618

Abstract

Background subtraction based on change detection is the first step in many computer vision systems. Many background subtraction methods have been proposed to detect foreground objects through background modeling. However, most of these methods are pixel-based, which only use pixel-by-pixel comparisons, and a [...] Read more.

Background subtraction based on change detection is the first step in many computer vision systems. Many background subtraction methods have been proposed to detect foreground objects through background modeling. However, most of these methods are pixel-based, which only use pixel-by-pixel comparisons, and a few others are spatial-based, which take the neighborhood of each analyzed pixel into consideration. In this paper, inspired by a illumination- invariant feature based on locality-sensitive histograms proposed for object tracking, we first develop a novel texture descriptor named the Local Similarity Statistical Descriptor (LSSD), which calculates the similarity between the current pixel and its neighbors. The LSSD descriptor shows good performance in illumination variation and dynamic background scenes. Then, we model each background pixel representation with a combination of color features and LSSD features. These features are then embedded in a low-cost and highly efficient background modeling framework. The color and texture features have their own merits and demerits; they can compensate each other, resulting in better performance. Both quantitative and qualitative evaluations carried out on the change detection dataset are provided to demonstrate the effectiveness of our method. Full article

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13 pages, 6580 KiB

Open AccessArticle

A Study of Two Dimensional Tomography Reconstruction of Temperature and Gas Concentration in a Combustion Field Using TDLAS

by Pengshuai Sun^1,2

, Zhirong Zhang^1,2,*, Zhe Li^1,3, Qiang Guo¹ and Fengzhong Dong^1,2,3,*

¹ Anhui Provincial Key Laboratory of Photonic Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China

² Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China

³ School of Environmental Science & Optoelectronic Technology, University of Science and Technology of China, Hefei 230026, China

Appl. Sci. 2017, 7(10), 990; https://doi.org/10.3390/app7100990 - 25 Sep 2017

Cited by 37 | Viewed by 5802

Abstract

Based on tunable diode laser absorption spectroscopy (TDLAS), two-dimensional (2D) distribution reconstructions of gas concentration and temperature are realized using an algebraic reconstruction technique (ART). The influence of the beam distribution and grid size on combustion field reconstruction is investigated to attain optimal [...] Read more.

Based on tunable diode laser absorption spectroscopy (TDLAS), two-dimensional (2D) distribution reconstructions of gas concentration and temperature are realized using an algebraic reconstruction technique (ART). The influence of the beam distribution and grid size on combustion field reconstruction is investigated to attain optimal reconstruction results with a limited number of beams. Under limited optical-path numbers, it shows that a better spatial resolution is attainable only when the laser beam paths are vertical and parallel to the symmetry axis of the combustion field. Furthermore, experiments with 16 beam paths using one and two flat flame combustion fields are carried out in different fuel-air equivalence ratios under room temperature. The results are in agreement with the simulation results, and the time resolution is less than 1 s. Full article

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14 pages, 2770 KiB

Open AccessArticle

Analysis of the Aging Processes of Writing Ink: Raman Spectroscopy versus Gas Chromatography Aspects

by Nikolai M. Grechukha¹, Kseniya O. Gorshkova², Maxim S. Panov², Ilya I. Tumkin², Elizaveta O. Kirillova³, Vladimir V. Lukianov⁴, Natalia P. Kirillova⁴ and Vladimir A. Kochemirovsky^2,5,*

¹ Chamber of Judicial Experts (Sudex), Moscow 127018, Russia

² Institute of Chemistry, Saint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034, Russia

³ LLC Inter-Regional Economic and Legal Office, St. Petersburg, Russia

⁴ Department of Criminal Law, Saint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034, Russia

⁵ LLC Laser Chemistry, St. Petersburg, Russia

Appl. Sci. 2017, 7(10), 991; https://doi.org/10.3390/app7100991 - 26 Sep 2017

Cited by 25 | Viewed by 8481

Abstract

This work is devoted to the extremely popular but poorly developed scientific and forensic problem of the estimation of the actual dates of inscriptions placed on paper and made by ballpoint pens. It is shown that the degradation of writing inks with time [...] Read more.

This work is devoted to the extremely popular but poorly developed scientific and forensic problem of the estimation of the actual dates of inscriptions placed on paper and made by ballpoint pens. It is shown that the degradation of writing inks with time may be controlled via Raman spectroscopy and gas chromatography. The time intervals for the implementation of each of these methods were determined using the ratios of the Raman peak intensities as degradation characteristics rather than their absolute values. In turn, this eliminates the effect of the concentration of a dye. The mutual influence of the volatile components and dyes of writing inks was also investigated and the time interval within which such influence is critical was found. According to the obtained results, a new methodological scheme for determining the age of documents, which were created at least 40 months ago, was proposed. Full article

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

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25 pages, 15513 KiB

Open AccessArticle

Classification of Architectural Heritage Images Using Deep Learning Techniques

by Jose Llamas^1,*

, Pedro M. Lerones¹, Roberto Medina¹, Eduardo Zalama² and Jaime Gómez-García-Bermejo²

¹ CARTIF Foundation, Parque Tecnológico de Boecillo, 47151 Valladolid, Spain

² ITAP-DISA, University of Valladolid, Pl. Santa Cruz, 8, 47002 Valladolid, Spain

Appl. Sci. 2017, 7(10), 992; https://doi.org/10.3390/app7100992 - 26 Sep 2017

Cited by 167 | Viewed by 14311

Abstract

The classification of the images taken during the measurement of an architectural asset is an essential task within the digital documentation of cultural heritage. A large number of images are usually handled, so their classification is a tedious task (and therefore prone to [...] Read more.

The classification of the images taken during the measurement of an architectural asset is an essential task within the digital documentation of cultural heritage. A large number of images are usually handled, so their classification is a tedious task (and therefore prone to errors) and habitually consumes a lot of time. The availability of automatic techniques to facilitate these sorting tasks would improve an important part of the digital documentation process. In addition, a correct classification of the available images allows better management and more efficient searches through specific terms, thus helping in the tasks of studying and interpreting the heritage asset in question. The main objective of this article is the application of techniques based on deep learning for the classification of images of architectural heritage, specifically through the use of convolutional neural networks. For this, the utility of training these networks from scratch or only fine tuning pre-trained networks is evaluated. All this has been applied to classifying elements of interest in images of buildings with architectural heritage value. As no datasets of this type, suitable for network training, have been located, a new dataset has been created and made available to the public. Promising results have been obtained in terms of accuracy and it is considered that the application of these techniques can contribute significantly to the digital documentation of architectural heritage. Full article

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17 pages, 5069 KiB

Open AccessArticle

A New Approach to Fall Detection Based on the Human Torso Motion Model

by Leiyue Yao, Weidong Min^* and Keqiang Lu

School of Information Engineering, Nanchang University, Nanchang 330031, China

Appl. Sci. 2017, 7(10), 993; https://doi.org/10.3390/app7100993 - 26 Sep 2017

Cited by 24 | Viewed by 5994

Abstract

This paper presents a new approach for fall detection based on two features and their motion characteristics extracted from the human torso. The 3D positions of the hip center joint and the shoulder center joint in depth images are used to build a [...] Read more.

This paper presents a new approach for fall detection based on two features and their motion characteristics extracted from the human torso. The 3D positions of the hip center joint and the shoulder center joint in depth images are used to build a fall detection model named the human torso motion model (HTMM). Person’s torso angle and centroid height are imported as key features in HTMM. Once a person comes into the scene, the positions of these two joints are fetched to calculate the person’s torso angle. Whenever the angle is larger than a given threshold, the changing rates of the torso angle and the centroid height are recorded frame by frame in a given period of time. A fall can be identified when the above two changing rates reach the thresholds. By using the new feature, falls can be accurately and effectively distinguished from other fall-like activities, which are very difficult for other computer vision-based approaches to differentiate. Experiment results show that our approach achieved a detection accuracy of 97.5%, 98% true positive rate (TPR) and 97% true negative rate (TNR). Furthermore, the approach is time efficient and robust because of only calculating the changing rate of gravity and centroid height. Full article

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18 pages, 9758 KiB

Open AccessArticle

Principles and Application of Polyimide Fiber Bragg Gratings for Surface Strain Measurement

by Yangyang Sun¹, Jianyong Liu^1,*, Yuan Wang², Qinghua Zhang¹, Jianli Duan¹, Zhenglin Zhang¹, Xiaodi Huang¹ and Zewei You¹

¹ College of Defense Engineering, PLA University of Science and technology, Nanjing 210007, China

² Nanjing University of Science and technology, Nanjing 210094, China

Appl. Sci. 2017, 7(10), 995; https://doi.org/10.3390/app7100995 - 26 Sep 2017

Cited by 13 | Viewed by 5109

Abstract

Although theoretical investigation has demonstrated that fewer strain transfer layers imply a greater strain transfer ratio, as well as increased accuracy, most researchers are still focused on investigating encapsulated Fiber Bragg gratings (FBGs) in surface strain measurements. This is because, in a traditional [...] Read more.

Although theoretical investigation has demonstrated that fewer strain transfer layers imply a greater strain transfer ratio, as well as increased accuracy, most researchers are still focused on investigating encapsulated Fiber Bragg gratings (FBGs) in surface strain measurements. This is because, in a traditional view, bare FBGs are too fragile to be mounted on the substrate for measuring surface strain. Polyimide FBGs may provide a better balance point between accuracy and protection. A new method to measure surface strain with polyimide fiber Bragg gratings is proposed. Bare polyimide FBGs have a polyimide coating, but like regular non-coated FBGs. This gives polyimide FBGs a higher strain transfer ratio and response frequency. Bare polyimide FBGs can be considered as uncoated FBGs. The coupling of the matrix material of polyimide FBGs is improved as compared to FBGs without coating. In order to verify the capacity for surface strain measurement, polyimide FBGs are mounted to obtain the surface strain of a concrete specimen with SM130-700 interrogator from Micron Optics Incorporation (MOI) with a sampling frequency maximum of 2000 Hz. The experiment demonstrates that polyimide FBGs work well even in dynamic surface strain measurements such as explosion measurement. Validation experiment in this paper also proposed that fewer strain transfer layers can increase dynamic response frequency and coupling between FBG and substrate. Full article

(This article belongs to the Section Mechanical Engineering)

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14 pages, 564 KiB

Open AccessArticle

Elastohydrodynamic Performance of a Bio-Based, Non-Corrosive Ionic Liquid

by Marcus Björling^1,*

, Scott Bair², Liwen Mu³, Jiahua Zhu³ and Yijun Shi¹

¹ Division of Machine Elements, Department of Engineering Science and Mathematics, Luleå University of Technology, SE-97187 Luleå, Sweden

² Georgia Institute of Technology, Centre for High Pressure Rheology, G.W. Woodruff School of Mechanical Engineering, Atlanta, GA 30332-0405, USA

³ Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA

Appl. Sci. 2017, 7(10), 996; https://doi.org/10.3390/app7100996 - 27 Sep 2017

Cited by 19 | Viewed by 4964

Abstract

To improve performance of machine components, lubrication is one of the most important factors. Especially for use in extreme environments, researchers look for other solutions rather than common lubricant base stocks like mineral oils or vegetable oils. One such example is ionic liquids. [...] Read more.

To improve performance of machine components, lubrication is one of the most important factors. Especially for use in extreme environments, researchers look for other solutions rather than common lubricant base stocks like mineral oils or vegetable oils. One such example is ionic liquids. Ionic liquids have been defined as molten salts with melting points below 100

^{\circ}

C that are entirely ionic in nature, comprising both cationic and anionic species. The industrial use of ionic liquids is mostly as solvents, electrolytes, extractants and catalysts. In tribological applications, ionic liquids are mainly studied in boundary lubrication and in pure sliding contacts. In this work, the elastohydrodynamic performance of a bio-based, non-corrosive, [choline][l-proline] ionic liquid is evaluated in terms of pressure-viscosity response, film forming capability and friction. The results show a pressure-viscosity coefficient of below 8 GPa

^{- 1}

at 25

^{\circ}

C, among the lowest reported for any ionic liquid. The ionic liquid generated up to 70% lower friction than a reference paraffin oil with a calculated difference in film thickness of 11%. It was also shown that this ionic liquid is very hygroscopic, which is believed to explain part of the low friction results, but also has to be considered in practical applications since the water content will influence the properties and thus the performance of the lubricant. Full article

(This article belongs to the Section Mechanical Engineering)

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7 pages, 1482 KiB

Open AccessArticle

A High-Energy, 100 Hz, Picosecond Laser for OPCPA Pumping

by Hongpeng Su^1,2, Yujie Peng^1,*, Junchi Chen¹, Yanyan Li¹, Pengfei Wang^1,2 and Yuxin Leng^1,*

¹ State Key Laboratory of High Field Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, 390# Qinghe Road, Jiading District, Shanghai 201800, China

² University of Chinese Academy of Sciences, Beijing 100190, China

Appl. Sci. 2017, 7(10), 997; https://doi.org/10.3390/app7100997 - 27 Sep 2017

Cited by 15 | Viewed by 6402

Abstract

A high-energy diode-pumped picosecond laser system centered at 1064 nm for optical parametric chirped pulse amplifier (OPCPA) pumping was demonstrated. The laser system was based on a master oscillator power amplifier configuration, which contained an Nd:YVO₄ mode-locked seed laser, an LD-pumped Nd:YAG [...] Read more.

A high-energy diode-pumped picosecond laser system centered at 1064 nm for optical parametric chirped pulse amplifier (OPCPA) pumping was demonstrated. The laser system was based on a master oscillator power amplifier configuration, which contained an Nd:YVO₄ mode-locked seed laser, an LD-pumped Nd:YAG regenerative amplifier, and two double-pass amplifiers. A reflecting volume Bragg grating with a 0.1 nm reflective bandwidth was used in the regenerative amplifier for spectrum narrowing and pulse broadening to suit the pulse duration of the optical parametric amplifier (OPA) process. Laser pulses with an energy of 316.5 mJ and a pulse duration of 50 ps were obtained at a 100 Hz repetition rate. A top-hat beam distribution and a 0.53% energy stability (RMS) were achieved in this system. Full article

(This article belongs to the Special Issue Solid State Lasers Materials, Technologies and Applications)

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10 pages, 1478 KiB

Open AccessArticle

Organic Electrochemical Transistor Microplate for Real-Time Cell Culture Monitoring

by Ota Salyk^1,*, Jan Víteček², Lukáš Omasta¹, Eva Šafaříková^2,3, Stanislav Stříteský¹, Martin Vala¹

and Martin Weiter¹

¹ Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 61200 Brno, Czech Republic

² Institute of Biophysics AS CR, Královopolská 135, 61265 Brno, Czech Republic

³ Department of Experimental Biology, Faculty of Science, Masaryk University, University Campus Bohunice, Kamenice 5, 62500 Brno, Czech Republic

Appl. Sci. 2017, 7(10), 998; https://doi.org/10.3390/app7100998 - 27 Sep 2017

Cited by 14 | Viewed by 5928

Abstract

Human cell cultures provide a potentially powerful means for pharmacological and toxicological research. A microplate with a multielectrode array of 96 organic electrochemical transistors (OECTs) based on the semiconductive polymer poly(3,4-ethylenedioxythio-phene):poly(styrene sulfonic acid) PEDOT:PSS was developed and fabricated by the screen printing method. [...] Read more.

Human cell cultures provide a potentially powerful means for pharmacological and toxicological research. A microplate with a multielectrode array of 96 organic electrochemical transistors (OECTs) based on the semiconductive polymer poly(3,4-ethylenedioxythio-phene):poly(styrene sulfonic acid) PEDOT:PSS was developed and fabricated by the screen printing method. It consists of a microplate of a 12 × 8 chimney–well array with transistors on the bottom. The OECT is circular with a channel of 1.5 mm² in the centre surrounded by the circular gate electrode. The device is designed for electrogenic cell monitoring. Simulations with the electrolyte revealed good electrical characteristics and indicated the setup information of the experimental conditions. A transconductance of g = 1.4 mS was achieved in the wide range of gate voltages V_gs = ±0.4 V when the drain potential V_ds = −0.735 V was set and the long term relaxation was compensated for. The time constant 0.15 s limited by the channel-electrolyte charge electrical double layer (EDL) capacitance was measured. The device was tested on a 3T3 fibroblast cell culture and the sudden environmental changes were recorded. The living cells can be observed on the channel of the OECT and during electrical stimulation by gate voltage, as well as during the source current response. Full article

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

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17 pages, 2279 KiB

Open AccessArticle

Bit- and Power-Loading—A Comparative Study on Maximizing the Capacity of RSOA Based Colorless DMT Transmitters

by Simon Arega Gebrewold^1,2,*, Romain Bonjour¹, Romain Brenot³, David Hillerkuss^1,4 and Juerg Leuthold¹

¹ Institute of Electromagnetic Fields (IEF), ETH Zurich, 8092 Zurich, Switzerland

² Now with RANOVUS GmbH, Nordostpark 07, 90411 Nuremberg, Germany

³ Thales Research and Technology and CEA Leti, Route de Nozay, a Joint Lab of Alcatel-Lucent Bell Labs France, III-V Lab, 91460 Marcoussis, France

⁴ Now with Huawei Technologies Duesseldorf GmbH, Optical & Quantum Laboratory, Riesstrasse 25-C3, 80992 Munich, Germany

Appl. Sci. 2017, 7(10), 999; https://doi.org/10.3390/app7100999 - 27 Sep 2017

Cited by 5 | Viewed by 5663

Abstract

We present a comparative study of the capacity increase brought by bit- and power-loading discrete multi-tone (DMT) modulation for low-cost colorless transmitters. Three interesting reflective semiconductor optical amplifier (RSOA) based colorless transmitter configurations are compared: First, an amplified spontaneous emission (ASE) spectrum-sliced source; [...] Read more.

We present a comparative study of the capacity increase brought by bit- and power-loading discrete multi-tone (DMT) modulation for low-cost colorless transmitters. Three interesting reflective semiconductor optical amplifier (RSOA) based colorless transmitter configurations are compared: First, an amplified spontaneous emission (ASE) spectrum-sliced source; second, a self-seeded RSOA fiber cavity laser (FCL) and third, an externally seeded RSOA. With bit- and power-loaded DMT, we report record high line rates of 6.25, 20.1 and 30.7 Gbit/s and line rates of 4.17, 10.1 and 24.5 Gbit/s in a back-to-back and in a 25 km nonzero dispersion shifted fiber (NZDSF) transmission experiments for the three transmitter configurations, respectively. In all the experiments, BER (bit error ratios) below an FEC (forward error correction) limit of 7.5 × 10⁻³ were achieved. Full article

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

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14 pages, 11211 KiB

Open AccessArticle

Shallow Landslide Susceptibility Modeling Using the Data Mining Models Artificial Neural Network and Boosted Tree

by Hyun-Joo Oh¹ and Saro Lee^2,3,*

¹ Department of Geological Hazards, Korea Institute of Geoscience and Mineral Resources (KIGAM), 124, Gwahang-ro, Yuseong-gu, Daejeon 34132, Korea

² Geological Research Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), 124, Gwahak-ro, Yuseong-gu, Daejeon 34132, Korea

³ Korea University of Science and Technology, 217 Gajeong-ro Yuseong-gu, Daejeon 305-350, Korea

Appl. Sci. 2017, 7(10), 1000; https://doi.org/10.3390/app7101000 - 28 Sep 2017

Cited by 67 | Viewed by 6790

Abstract

The main purpose of this paper is to present some potential applications of sophisticated data mining techniques, such as artificial neural network (ANN) and boosted tree (BT), for landslide susceptibility modeling in the Yongin area, Korea. Initially, landslide inventory was detected from visual [...] Read more.

The main purpose of this paper is to present some potential applications of sophisticated data mining techniques, such as artificial neural network (ANN) and boosted tree (BT), for landslide susceptibility modeling in the Yongin area, Korea. Initially, landslide inventory was detected from visual interpretation using digital aerial photographic maps with a high resolution of 50 cm taken before and after the occurrence of landslides. The debris flows were randomly divided into two groups: training and validation sets with a 50:50 proportion. Additionally, 18 environmental factors related to landslide occurrence were derived from the topography, soil, and forest maps. Subsequently, the data mining techniques were applied to identify the influence of environmental factors on landslide occurrence of the training set and assess landslide susceptibility. Finally, the landslide susceptibility indexes from ANN and BT were compared with a validation set using a receiver operating characteristics curve. The slope gradient, topographic wetness index, and timber age appear to be important factors in landslide occurrence from both models. The validation result of ANN and BT showed 82.25% and 90.79%, which had reasonably good performance. The study shows the benefit of selecting optimal data mining techniques in landslide susceptibility modeling. This approach could be used as a guideline for choosing environmental factors on landslide occurrence and add influencing factors into landslide monitoring systems. Furthermore, this method can rank landslide susceptibility in urban areas, thus providing helpful information when selecting a landslide monitoring site and planning land-use. Full article

(This article belongs to the Special Issue Application of Artificial Neural Networks in Geoinformatics)

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16 pages, 3312 KiB

Open AccessArticle

Comparative Research on RC Equivalent Circuit Models for Lithium-Ion Batteries of Electric Vehicles

by Lijun Zhang^1,*

, Hui Peng¹, Zhansheng Ning¹, Zhongqiang Mu¹ and Changyan Sun²

¹ National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083, China

² School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China

Appl. Sci. 2017, 7(10), 1002; https://doi.org/10.3390/app7101002 - 28 Sep 2017

Cited by 201 | Viewed by 18310

Abstract

Equivalent circuit models are a hot research topic in the field of lithium-ion batteries for electric vehicles, and scholars have proposed a variety of equivalent circuit models, from simple to complex. On one hand, a simple model cannot simulate the dynamic characteristics of [...] Read more.

Equivalent circuit models are a hot research topic in the field of lithium-ion batteries for electric vehicles, and scholars have proposed a variety of equivalent circuit models, from simple to complex. On one hand, a simple model cannot simulate the dynamic characteristics of batteries; on the other hand, it is difficult to apply a complex model to a real-time system. At present, there are few systematic comparative studies on equivalent circuit models of lithium-ion batteries. The representative first-order resistor-capacitor (RC) model and second-order RC model commonly used in the literature are studied comparatively in this paper. Firstly, the parameters of the two models are identified experimentally; secondly, the simulation model is built in Matlab/Simulink environment, and finally the output precision of these two models is verified by the actual data. The results show that in the constant current condition, the maximum error of the first-order RC model is 1.65% and the maximum error for the second-order RC model is 1.22%. In urban dynamometer driving schedule (UDDS) condition, the maximum error of the first-order RC model is 1.88%, and for the second-order RC model the maximum error is 1.69%. This is of great instructional significance to the application in practical battery management systems for the equivalent circuit model of lithium-ion batteries of electric vehicles. Full article

(This article belongs to the Special Issue Battery Management and State Estimation)

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26 pages, 5581 KiB

Open AccessArticle

A Cubature-Principle-Assisted IMM-Adaptive UKF Algorithm for Maneuvering Target Tracking Caused by Sensor Faults

by Huan Zhou¹

, Hui Zhao^1,*, Hanqiao Huang^1,2,* and Xin Zhao¹

¹ Aeronautics and Astronautics Engineering College, Air Force Engineering University, Xi’an 710038, China

² Astronautics College, Northwestern Polytechnic University, Xi’an 710072, China

Appl. Sci. 2017, 7(10), 1003; https://doi.org/10.3390/app7101003 - 28 Sep 2017

Cited by 12 | Viewed by 4332

Abstract

Aimed at solving the problem of decreased filtering precision while maneuvering target tracking caused by non-Gaussian distribution and sensor faults, we developed an efficient interacting multiple model-unscented Kalman filter (IMM-UKF) algorithm. By dividing the IMM-UKF into two links, the algorithm introduces the cubature [...] Read more.

Aimed at solving the problem of decreased filtering precision while maneuvering target tracking caused by non-Gaussian distribution and sensor faults, we developed an efficient interacting multiple model-unscented Kalman filter (IMM-UKF) algorithm. By dividing the IMM-UKF into two links, the algorithm introduces the cubature principle to approximate the probability density of the random variable, after the interaction, by considering the external link of IMM-UKF, which constitutes the cubature-principle-assisted IMM method (CPIMM) for solving the non-Gaussian problem, and leads to an adaptive matrix to balance the contribution of the state. The algorithm provides filtering solutions by considering the internal link of IMM-UKF, which is called a new adaptive UKF algorithm (NAUKF) to address sensor faults. The proposed CPIMM-NAUKF is evaluated in a numerical simulation and two practical experiments including one navigation experiment and one maneuvering target tracking experiment. The simulation and experiment results show that the proposed CPIMM-NAUKF has greater filtering precision and faster convergence than the existing IMM-UKF. The proposed algorithm achieves a very good tracking performance, and will be effective and applicable in the field of maneuvering target tracking. Full article

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20 pages, 4817 KiB

Open AccessArticle

A Rolling Bearing Fault Diagnosis Method Based on Variational Mode Decomposition and an Improved Kernel Extreme Learning Machine

by Ke Li^1,*, Lei Su¹, Jingjing Wu¹, Huaqing Wang^2,*

and Peng Chen³

¹ Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology, Jiangnan University, 1800 Li Hu Avenue, Wuxi 214122, Jiangsu, China

² School of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, ChaoYang District, Beijing 100029, China

³ Graduate School of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan

Appl. Sci. 2017, 7(10), 1004; https://doi.org/10.3390/app7101004 - 29 Sep 2017

Cited by 75 | Viewed by 6498

Abstract

Rolling bearings are key components of rotary machines. To ensure early effective fault diagnosis for bearings, a new rolling bearing fault diagnosis method based on variational mode decomposition (VMD) and an improved kernel extreme learning machine (KELM) is proposed in this paper. A [...] Read more.

Rolling bearings are key components of rotary machines. To ensure early effective fault diagnosis for bearings, a new rolling bearing fault diagnosis method based on variational mode decomposition (VMD) and an improved kernel extreme learning machine (KELM) is proposed in this paper. A fault signal is decomposed via VMD to obtain the intrinsic mode function (IMF) components, and the approximate entropy (ApEn) of the IMF component containing the main fault information is calculated. An eigenvector is created from the approximate entropy of each component. A bearing diagnosis model is created via a KELM; the KELM parameters are optimized using the particle swarm optimization (PSO) algorithm to obtain a KELM diagnosis model with optimal parameters. Finally, the effectiveness of the diagnosis method proposed in this paper is verified via a fan bearing fault diagnosis test. Under identical conditions, the result is compared with the results obtained using a back propagation (BP) neural network, a conventional extreme learning machine (ELM), and a support vector machine (SVM). The test result shows that the method proposed in this paper is superior to the other three methods in terms of diagnostic accuracy. Full article

(This article belongs to the Section Mechanical Engineering)

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16 pages, 5422 KiB

Open AccessArticle

Design and Experimental Development of a Pneumatic Stiffness Adjustable Foot System for Biped Robots Adaptable to Bumps on the Ground

by Xizhe Zang^1,*, Yixiang Liu^1,2,3

, Wenyuan Li¹, Zhenkun Lin¹ and Jie Zhao¹

¹ State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150080, China

² Legs + Walking Lab, Shirley Ryan AbilityLab (Formerly the Rehabilitation Institute of Chicago), Chicago, IL 60611, USA

³ Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA

Appl. Sci. 2017, 7(10), 1005; https://doi.org/10.3390/app7101005 - 29 Sep 2017

Cited by 6 | Viewed by 4978

Abstract

Walking on rough terrains still remains a challenge that needs to be addressed for biped robots because the unevenness on the ground can easily disrupt the walking stability. This paper proposes a novel foot system with passively adjustable stiffness for biped robots which [...] Read more.

Walking on rough terrains still remains a challenge that needs to be addressed for biped robots because the unevenness on the ground can easily disrupt the walking stability. This paper proposes a novel foot system with passively adjustable stiffness for biped robots which is adaptable to small-sized bumps on the ground. The robotic foot is developed by attaching eight pneumatic variable stiffness units to the sole separately and symmetrically. Each variable stiffness unit mainly consists of a pneumatic bladder and a mechanical reversing valve. When walking on rough ground, the pneumatic bladders in contact with bumps are compressed, and the corresponding reversing valves are triggered to expel out the air, enabling the pneumatic bladders to adapt to the bumps with low stiffness; while the other pneumatic bladders remain rigid and maintain stable contact with the ground, providing support to the biped robot. The performances of the proposed foot system, including the variable stiffness mechanism, the adaptability on the bumps of different heights, and the application on a biped robot prototype are demonstrated by various experiments. Full article

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

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15 pages, 2959 KiB

Open AccessArticle

The Effect of Magnetic Field on Thermal-Reaction Kinetics of a Paramagnetic Metal Hydride Storage Bed

by Shahin Shafiee¹

, Mary Helen McCay¹ and Sarada Kuravi^2,*

¹ National Center for Hydrogen Research, Florida Institute of Technology, Melbourne, FL 32901, USA

² Department of Mechanical and Aerospace Engineering, New Mexico State University, Las Cruces, NM 88003, USA

Appl. Sci. 2017, 7(10), 1006; https://doi.org/10.3390/app7101006 - 29 Sep 2017

Cited by 10 | Viewed by 5707

Abstract

A safe and efficient method for storing hydrogen is solid state storage through a chemical reaction in metal hydrides. A good amount of research has been conducted on hydrogenation properties of metal hydrides and possible methods to improve them. Background research shows that [...] Read more.

A safe and efficient method for storing hydrogen is solid state storage through a chemical reaction in metal hydrides. A good amount of research has been conducted on hydrogenation properties of metal hydrides and possible methods to improve them. Background research shows that heat transfer is one of the reaction rate controlling parameters in a metal hydride hydrogen storage system. Considering that some very well-known hydrides like lanthanum nickel (LaNi₅) and magnesium hydride (MgH₂) are paramagnetic materials, the effect of an external magnetic field on heat conduction and reaction kinetics in a metal hydride storage system with such materials needs to be studied. In the current paper, hydrogenation properties of lanthanum nickel under magnetism were studied. The properties which were under consideration include reaction kinetics, hydrogen absorption capacity, and hydrogenation time. Experimentation has proven the positive effect of applying magnetic fields on the heat conduction, reaction kinetics, and hydrogenation time of a lanthanum nickel bed. However, magnetism did not increase the hydrogenation capacity of lanthanum nickel, which is evidence to prove that elevated hydrogenation characteristics result from enhanced heat transfer in the bed. Full article

(This article belongs to the Special Issue Clean Energy and Fuel (Hydrogen) Storage)

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17 pages, 2376 KiB

Open AccessArticle

An Analytical Solution for Block Toppling Failure of Rock Slopes during an Earthquake

by Songfeng Guo^1,2, Shengwen Qi^1,2,*, Guoxiang Yang³, Shishu Zhang⁴ and Charalampos Saroglou⁵

¹ Key Laboratory of Shale Gas and Geoengineering, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China

² College of Earth Science, University of Chinese Academy of Sciences, Beijing 100049, China

³ School of Engineering and Technology, China University of Geosciences (Beijing), Beijing 100083, China

⁴ Chengdu Engineering Corporation Limited, Power China, Chengdu 610072, China

⁵ School of Civil Engineering, National Technical University of Athens, Athens 15773, Greece

Appl. Sci. 2017, 7(10), 1008; https://doi.org/10.3390/app7101008 - 29 Sep 2017

Cited by 29 | Viewed by 8594

Abstract

Toppling failure is one of the most common failure types in the field. It always occurs in rock masses containing a group of dominant discontinuities dipping into the slope. Post-earthquake investigation has shown that many toppling rock slope failures have occurred during earthquakes. [...] Read more.

Toppling failure is one of the most common failure types in the field. It always occurs in rock masses containing a group of dominant discontinuities dipping into the slope. Post-earthquake investigation has shown that many toppling rock slope failures have occurred during earthquakes. In this study, an analytical solution is presented on the basis of limit equilibrium analysis. The acceleration of seismic load as well as joint persistence within the block base, were considered in the analysis. The method was then applied into a shake table test of an anti-dip layered slope model. As predicted from the analytical method, blocks topple or slide from slope crest to toe progressively and the factor of safety decreases as the inputting acceleration increases. The results perfectly duplicate the deformation features and stability condition of the physical model under the shake table test. It is shown that the presented method is more universal than the original one and can be adopted to evaluate the stability of the slope with potential toppling failure under seismic loads. Full article

(This article belongs to the Section Mechanical Engineering)

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14 pages, 6211 KiB

Open AccessArticle

B₄C-Al Composites Fabricated by the Powder Metallurgy Process

by Ling Zhang, Jianmin Shi, Chunlei Shen, Xiaosong Zhou^*

, Shuming Peng and Xinggui Long

Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China

Appl. Sci. 2017, 7(10), 1009; https://doi.org/10.3390/app7101009 - 29 Sep 2017

Cited by 29 | Viewed by 6122

Abstract

Due to the large thermal neutron absorption cross section of ¹⁰B, B₄C-Al composites have been used as neutron absorbing materials in nuclear industries, which can offer not only good neutron shielding performance but also excellent mechanical properties. The distribution of [...] Read more.

Due to the large thermal neutron absorption cross section of ¹⁰B, B₄C-Al composites have been used as neutron absorbing materials in nuclear industries, which can offer not only good neutron shielding performance but also excellent mechanical properties. The distribution of B₄C particles affects the mechanical performance and efficiency of the thermal neutron absorption of the composite materials. In this study, 15 wt % B₄C-Al and 20 wt % B₄C-Al composites were prepared using a powder metallurgy process, i.e., ball milling followed by pressing, sintering, hot-extrusion, and hot-rolling. The yield and tensile strengths of the composites were markedly increased with an increase in the milling energy and the percentages of B₄C particles. Microstructure analysis and neutron radiography revealed that the high-energy ball milling induced the homogeneous distribution of B₄C particles in the Al matrix and good bonding between the Al matrix and the B₄C particles. The load transfer ability and mechanical properties of the composites were consequently improved. The results showed the high-energy ball milling process is an appropriate fabrication procedure to prevent the agglomeration of the reinforcement particles even if the matrix to reinforcement particle size ratio was nearly 10. Full article

(This article belongs to the Special Issue Radiation Effects of Materials with Laser, Ion Beam and Rays)

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13 pages, 1814 KiB

Open AccessArticle

Effect of Steel Fiber and Different Environments on Flexural Behavior of Reinforced Concrete Beams

by Mohammad Ali Barkhordari Bafghi¹, Fereydon Amini^1,*, Hamed Safaye Nikoo¹ and Hamed Sarkardeh²

¹ School of Civil Engineering, Iran University of Science and Technology, Tehran 98021, Iran

² Department of Civil Engineering, School of Engineering, Hakim Sabzevari University, Sabzevar 980571, Iran

Appl. Sci. 2017, 7(10), 1011; https://doi.org/10.3390/app7101011 - 30 Sep 2017

Cited by 21 | Viewed by 8370

Abstract

The main kind of deterioration in marine Reinforced Concrete (RC) structures and other infrastructures is steel bar corrosion due to cracks in concrete surfaces, which leads to the reduction of the load carrying capacity, ductility, and structural safety. It seems that steel fibers [...] Read more.

The main kind of deterioration in marine Reinforced Concrete (RC) structures and other infrastructures is steel bar corrosion due to cracks in concrete surfaces, which leads to the reduction of the load carrying capacity, ductility, and structural safety. It seems that steel fibers can reduce and delay the cracking, and increase the flexural strength and ductility of marine RC structures. To do so, in marine atmosphere and the tidal zone of the Oman Sea and fresh water, the flexural behavior of beams containing Plain Concrete (PC), Concrete with Steel fiber Reinforcement (SFRC), RC, Concrete with Steel fiber, and bar Reinforcement ((R+S)C) at 28, 90 and 180 days were determined. Beams were 99 un-cracked and pre-cracked beams, with dimensions of 200 × 200 × 750 mm. Based on results and at 180 days, the flexural strength and toughness of pre-cracked (R+S)C beams were 22%–43% higher than the pre-cracked RC beams. The effect of steel fiber on the increment of load capacity and the toughness of pre-cracked RC beams were approximately the same. By addition of steel fiber to un-cracked RC beams, load capacity and toughness were increased up to 20%. The load capacity and toughness in marine atmosphere and tidal zone were approximately 15% lower than the fresh water condition. Full article

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15 pages, 4618 KiB

Open AccessArticle

Physicochemical, Mineralogical and Microscopic Evaluation of Sustainable Bricks Manufactured with Construction Wastes

by Armando Aguilar-Penagos¹, José Manuel Gómez-Soberón^2,*

and María Neftalí Rojas-Valencia¹

¹ Institute of Engineering, Coordination of Environmental Engineering, National Autonomous University of Mexico, Av. Universidad 3000, Mexico City MX 04510, Mexico

² Department of Construction Technology, Barcelona School of Building Construction, Polytechnic University of Catalonia, Av. Doctor Marañón 44-50, Barcelona 08028, Spain

Appl. Sci. 2017, 7(10), 1012; https://doi.org/10.3390/app7101012 - 30 Sep 2017

Cited by 22 | Viewed by 6710

Abstract

At an international level, enormous volumes of construction and demolition wastes are generated: 170 million tons/year in the USA, 500 million tons/year in the European Union (EU) and 12 million tons/year in Mexico. Alternative uses for these heterogeneous materials, such as the manufacture [...] Read more.

At an international level, enormous volumes of construction and demolition wastes are generated: 170 million tons/year in the USA, 500 million tons/year in the European Union (EU) and 12 million tons/year in Mexico. Alternative uses for these heterogeneous materials, such as the manufacture of sustainable bricks, are potential solutions to this growing environmental issue. Based on previous studies, and in compliance with Mexican standards, four different types of secondary materials were utilized in the composition of a sustainable brick matrix. Temperature and solar radiation used for drying purposes were determined, as well as weight loss, resistance and initial maximum absorption. In order to characterize the resulting matrix, observations were made with a scanning electron microscope, and the chemical composition of the samples was determined by detecting basic compounds using mapping through SEM-EDS microanalysis, connected to the SEM unit. Finally, thermogravimetric analyses were performed to correlate mechanical and chemical behavior, and resistance to high temperatures of the mixtures. The results obtained showed that all-in-one (AiO) is the most appropriate material for brick manufacturing, Opuntia ficus-indica mucilage improves physical properties, such as increased compressive strength and reduced water absorption, while wood residues, clay minerals and illite enhance mechanical properties. Full article

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

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14 pages, 606 KiB

Open AccessArticle

ℓ_2,1 Norm and Hessian Regularized Non-Negative Matrix Factorization with Discriminability for Data Representation

by Peng Luo¹, Jinye Peng^1,* and Jianping Fan²

¹ College of Information and Technology, Northwest University of China, Xi’an 710127, China

² Department of Computer Science, University of North Carolina at Charlotte, Charlotte, NC 28223, USA

Appl. Sci. 2017, 7(10), 1013; https://doi.org/10.3390/app7101013 - 30 Sep 2017

Cited by 4 | Viewed by 4945

Abstract

Matrix factorization based methods have widely been used in data representation. Among them, Non-negative Matrix Factorization (NMF) is a promising technique owing to its psychological and physiological interpretation of spontaneously occurring data. On one hand, although traditional Laplacian regularization can enhance the performance [...] Read more.

Matrix factorization based methods have widely been used in data representation. Among them, Non-negative Matrix Factorization (NMF) is a promising technique owing to its psychological and physiological interpretation of spontaneously occurring data. On one hand, although traditional Laplacian regularization can enhance the performance of NMF, it still suffers from the problem of its weak extrapolating ability. On the other hand, standard NMF disregards the discriminative information hidden in the data and cannot guarantee the sparsity of the factor matrices. In this paper, a novel algorithm called

ℓ_{2, 1}

norm and Hessian Regularized Non-negative Matrix Factorization with Discriminability (

ℓ_{2, 1}

HNMFD), is developed to overcome the aforementioned problems. In

ℓ_{2, 1}

HNMFD, Hessian regularization is introduced in the framework of NMF to capture the intrinsic manifold structure of the data.

ℓ_{2, 1}

norm constraints and approximation orthogonal constraints are added to assure the group sparsity of encoding matrix and characterize the discriminative information of the data simultaneously. To solve the objective function, an efficient optimization scheme is developed to settle it. Our experimental results on five benchmark data sets have demonstrated that

ℓ_{2, 1}

HNMFD can learn better data representation and provide better clustering results. Full article

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18 pages, 3802 KiB

Open AccessArticle

A Comparative Study of Clustering Analysis Method for Driver’s Steering Intention Classification and Identification under Different Typical Conditions

by Yiding Hua¹

, Haobin Jiang^1,2,*, Huan Tian¹, Xing Xu² and Long Chen^1,2

¹ School of Automobile and Traffic Engineering, Jiangsu University, Zhenjiang 212013, China

² Automotive Engineering Research Institute, Jiangsu University, Zhenjiang 212013, China

Appl. Sci. 2017, 7(10), 1014; https://doi.org/10.3390/app7101014 - 30 Sep 2017

Cited by 17 | Viewed by 5398

Abstract

Driver’s intention classification and identification is identified as the key technology for intelligent vehicles and is widely used in a variety of advanced driver assistant systems (ADAS). To study driver’s steering intention under different typical operating conditions, five driving school coaches of different [...] Read more.

Driver’s intention classification and identification is identified as the key technology for intelligent vehicles and is widely used in a variety of advanced driver assistant systems (ADAS). To study driver’s steering intention under different typical operating conditions, five driving school coaches of different ages and genders are selected as the test drivers for a real vehicle test. Four kinds of typical car steering condition test data with four different vehicles are collected. Test data are filtered by the Butterworth filter and are used for extracting the driver steering characteristic parameters. Based on Principal Component Analysis (PCA), the three kinds of clustering analysis methods, including the Fuzzy C-Means algorithm (FCM), the Gustafson Full article

(This article belongs to the Special Issue Road Vehicles Surroundings Supervision: On-Board Sensors and Communications)

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12 pages, 2019 KiB

Open AccessFeature PaperArticle

Material Optimization for a High Power Thermoelectric Generator in Wearable Applications

by Gyusoup Lee¹, Garam Choi², Choong Sun Kim¹, Yong Jun Kim¹, Hyeongdo Choi¹, Seongho Kim¹, Hyo Seok Kim², Won Bo Lee² and Byung Jin Cho^1,*

¹ School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea

² School of Chemical and Biological Engineering, Seoul National University (SNU), 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea

Appl. Sci. 2017, 7(10), 1015; https://doi.org/10.3390/app7101015 - 30 Sep 2017

Cited by 9 | Viewed by 6872

Abstract

Thermoelectric power generation using human body heat can be applied to wearable sensors, and various applications are possible. Because the thermoelectric generator (TEG) is highly dependent on the thermoelectric material, research on improving the performance of the thermoelectric material has been conducted. Thus [...] Read more.

Thermoelectric power generation using human body heat can be applied to wearable sensors, and various applications are possible. Because the thermoelectric generator (TEG) is highly dependent on the thermoelectric material, research on improving the performance of the thermoelectric material has been conducted. Thus far, in developing thermoelectric materials, the researchers have focused on improving the figure of merit, ZT. For a TEG placed on the human body, however, the power density does not always increase as the material ZT increases. In this study, the material properties and ZT of P-type BiSbTe₃ were simulated for carrier concentration ranging from 3 × 10¹⁷ to 3 × 10²⁰ cm⁻³, and the power density of a TEG fabricated from the material dataset was calculated using a thermoelectric resistance model for human body application. The results revealed that the maximum ZT and the maximum power density were formed at different carrier concentrations. The material with maximum ZT showed 28.8% lower power density compared to the maximum obtainable power density. Further analysis confirmed that the mismatch in the optimum carrier concentration for the maximum ZT and maximum power density can be minimized when a material with lower thermal conductivity is used in a TEG. This study shows that the ZT enhancement of materials is not the highest priority in the production of a TEG for human body application, and material engineering to lower the thermal conductivity is required to reduce the optimum point mismatch problem. Full article

(This article belongs to the Special Issue Development and Application of Thermoelectric Power Generators, Energy Harvesters and Refrigerators)

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15 pages, 6329 KiB

Open AccessArticle

Experimental Study on the Performance of Polyurethane-Steel Sandwich Structure under Debris Flow

by Peizhen Li^1,2

, Shutong Liu² and Zheng Lu^1,2,*

¹ State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, China

² Research Institute of Structural Engineering and Disaster Reduction, Tongji University, Shanghai 200092, China

Appl. Sci. 2017, 7(10), 1018; https://doi.org/10.3390/app7101018 - 2 Oct 2017

Cited by 17 | Viewed by 4786

Abstract

Polyurethane-steel sandwich structure, which creatively uses the polyurethane-steel sandwich composite as a structural material, is proposed to strengthen the impact resistance of buildings under debris flow. The impact resistance of polyurethane-steel sandwich structure under debris flow is investigated by a series of impact [...] Read more.

Polyurethane-steel sandwich structure, which creatively uses the polyurethane-steel sandwich composite as a structural material, is proposed to strengthen the impact resistance of buildings under debris flow. The impact resistance of polyurethane-steel sandwich structure under debris flow is investigated by a series of impact loading tests, compared with that of traditional steel frame structures. Additionally, further discussions regarding the hidden mechanism are performed. During the whole impact process, as for steel frame structure, the impacted column appeared obvious local deformation both at its column base and on the impact surface, leading to remarkable decrease of its impact resistance; while the stress and strain of polyurethane-steel sandwich structure develops more uniformly and distribute further in the whole structure, maintaining excellent integrity and impact transmission capability. The impact loading tests confirm that polyurethane-steel sandwich structure possesses superior impact resistance under debris flow. This is of great practical significance for the prevention and reduction of geological disasters. 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, 5993 KiB

Open AccessArticle

Evaluation of Anti-Wear Properties of Metalworking Fluids Enhanced with Halloysite Nanotubes

by Laura Peña-Parás^1,*, José Antonio Sánchez-Fernández², Carlos Rafael Martínez¹, José Abraham Ontiveros¹, Karla Itzel Saldívar¹, Luis Manuel Urbina¹, Moisés Jair Arias¹, Patricio García-Pineda¹ and Brenda Castaños¹

¹ Departamento de Ingeniería, Universidad de Monterrey, 66238 San Pedro Garza García, Nuevo León, Mexico

² Escuela de Ingeniería y Ciencias, Tecnológico de Monterrey, Campus Monterrey, Eugenio Garza Sada 2501, Col. Tecnológico, 64849 Monterrey, Nuevo León, Mexico

Appl. Sci. 2017, 7(10), 1019; https://doi.org/10.3390/app7101019 - 3 Oct 2017

Cited by 11 | Viewed by 4609

Abstract

The study of nanoparticles as additives for metalworking fluids (MWFs) with applications in the metal removal processes, or machining, has received increasing attention due to the possible enhancements on tribological properties. In this study, low-cost and environmentally friendly nanoparticle additives of halloysite clay [...] Read more.

The study of nanoparticles as additives for metalworking fluids (MWFs) with applications in the metal removal processes, or machining, has received increasing attention due to the possible enhancements on tribological properties. In this study, low-cost and environmentally friendly nanoparticle additives of halloysite clay nanotubes (HNTs) were dispersed in metalworking fluids utilized for milling processes. Concentrations of 0.01, 0.05, 0.10 wt. % were incorporated into a mineral oil (MO) and a semi-synthetic fluid (SF) by ultrasonication. The anti-wear properties of metalworking nanofluids were characterized with a T-05 block-on-ring tribotester at a contact pressure of 0.5 GPa. Surface roughness of worn block materials was obtained with an optical 3D surface measurement system. Results showed that at a concentration of 0.10 wt. % HNTs block mass loss was lowered by 24% for the MO + HNTs nanofluids. For the SF + HNTs, a reduction of 63% and 32% in wear mass loss and coefficient of friction (COF), respectively, were found at the same concentration. The tribological enhancing mechanism for the applied contact pressure was proposed to be due to a reduction of the area of contact and nanoparticle sliding between surfaces with no HNT deposition, evidenced by energy dispersive spectrometry (EDS). Furthermore, surface roughness studies of worn blocks showed smoother surfaces with lower groove density with the addition of nanoparticle additives. The results of this study demonstrate that HNTs can improve the lubricity of metalworking cutting fluids used for machining processes, enhancing tool life and providing better surface finish of products. Full article

(This article belongs to the Section Nanotechnology and Applied Nanosciences)

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11 pages, 5118 KiB

Open AccessCommunication

Solution-Processed Environmentally Friendly Ag₂S Colloidal Quantum Dot Solar Cells with Broad Spectral Absorption

by Viktor A. Öberg, Xiaoliang Zhang, Malin B. Johansson

and Erik M. J. Johansson^*

Department of Chemistry-Ångström, Physical Chemistry Uppsala University, 75120 Uppsala, Sweden

Appl. Sci. 2017, 7(10), 1020; https://doi.org/10.3390/app7101020 - 3 Oct 2017

Cited by 15 | Viewed by 7572

Abstract

A facile heat-up synthesis route is used to synthesize environmentally friendly Ag₂S colloidal quantum dots (CQDs) that are applied as light absorbing material in solid state p-i-n junction solar cell devices. The as-synthesized Ag₂S CQDs have an average size [...] Read more.

A facile heat-up synthesis route is used to synthesize environmentally friendly Ag₂S colloidal quantum dots (CQDs) that are applied as light absorbing material in solid state p-i-n junction solar cell devices. The as-synthesized Ag₂S CQDs have an average size of around 3.5 nm and exhibit broad light absorption covering ultraviolet, visible, and near infrared wavelength regions. The solar cell devices are constructed with a device architecture of FTO/TiO₂/Ag₂S CQDs/hole transport material (HTM) /Au using a solution-processed approach. Different HTMs, N2,N2,N2′,N2′,N7,N7,N7′,N7′-octakis(4-methoxyphenyl)-9,9′-spirobi(9H-fluorene)-2,2′,7,7′ tetramine (spiro-OMeTAD), poly(3-hexylthiophene-2,5-diyl) (P3HT), and poly((2,3-bis(3-octyloxyphenyl)-5,8-quinoxalinediyl)-2,5-thiophenediyl) TQ1 are studied for maximizing the device photovoltaic performance. The solar cell device with P3HT as a hole transport material gives the highest performance and the solar cell exhibit broad spectral absorption. These results indicate that Ag₂S CQD have high potential for utilization as environmentally friendly light absorbing materials for solar cell application and that the hole transport material is critical to maximize the solar cell photovoltaic performance. Full article

(This article belongs to the Special Issue Quantum Materials)

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19 pages, 3775 KiB

Open AccessArticle

Application of Improved Hilbert–Huang Transform to Partial Discharge Defect Model Recognition of Power Cables

by FengChang Gu, HungCheng Chen^* and MengHung Chao

Department of Electrical Engineering, National Chin-Yi University of Technology, Taichung 41107, Taiwan

Appl. Sci. 2017, 7(10), 1021; https://doi.org/10.3390/app7101021 - 4 Oct 2017

Cited by 11 | Viewed by 4570

Abstract

As a key concern in a power system, a deteriorated insulation is likely to bring about a partial discharge phenomenon and hence degrades the power supply quality. Thus, a partial discharge test has been turned into an approach of significance to protect a [...] Read more.

As a key concern in a power system, a deteriorated insulation is likely to bring about a partial discharge phenomenon and hence degrades the power supply quality. Thus, a partial discharge test has been turned into an approach of significance to protect a power system from an unexpected malfunction. An improved Hilbert–Huang Transformation (HHT) is proposed in this work as an effective way to address the issues of an optimal shifting number and illusive components, both suffered in a conventional HHT approach, and is then applied to a defect mode recognition for a partial discharge signal analysis in the case of a cross-linked polyethylene insulated power cable. As the first step, the partial discharge signal detected is converted through the proposed improved HHT to a time-frequency-energy 3D spectrum. Then as the second step, the fractal features contained therein are extracted by way of a fractal theory, and in the end the defect modes are recognized as intended by use of an extension method. Full article

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

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8 pages, 1127 KiB

Open AccessArticle

Investigation of Effective Modification Treatments for Titanium Membranes

by Reiko Kobatake, Kazuya Doi^*, Yoshifumi Oki, Hanako Umehara, Hiromichi Kawano, Takayasu Kubo and Kazuhiro Tsuga

Department of Advanced Prosthodontics, Hiroshima University Graduate School of Biomedical and Health Sciences; 1‐2‐3, Kasumi, Minami‐ku, Hiroshima 734‐8553, Japan

Appl. Sci. 2017, 7(10), 1022; https://doi.org/10.3390/app7101022 - 4 Oct 2017

Cited by 5 | Viewed by 3583

Abstract

Titanium membranes are used for guided bone regeneration in implant therapy. However, as a bioinert material, titanium does not have the ability to accelerate bone formation. Various titanium surface treatments to confer bioactivity have been demonstrated; however, there are concerns about the influence [...] Read more.

Titanium membranes are used for guided bone regeneration in implant therapy. However, as a bioinert material, titanium does not have the ability to accelerate bone formation. Various titanium surface treatments to confer bioactivity have been demonstrated; however, there are concerns about the influence of chemical treatments for thin titanium membranes. This study investigated the influence of surface modifications on the structure of titanium membranes. Titanium membranes of 20 μm thickness were treated with acid or alkali solutions, and we evaluated their surface structure, wettability, thickness, and mechanical strength compared to non-treated membranes. Alkali-treated titanium membranes displayed the formation of nanoscale pore structures on their surfaces, enhanced hydrophilicity, and almost same thickness compared with acid-treated membranes. Furthermore, the tensile strength of alkali-treated membranes was comparable to non-treated membranes. These results suggest that alkali treatment is an appropriate surface modification method for titanium membranes. Full article

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

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28 pages, 957 KiB

Open AccessArticle

Strategies to Automatically Derive a Process Model from a Configurable Process Model Based on Event Data

by Mauricio Arriagada-Benítez^1,*, Marcos Sepúlveda¹

, Jorge Munoz-Gama¹

and Joos C. A. M. Buijs²

¹ Department of Computer Science, School of Engineering, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Santiago, Chile

² Department of Mathematics and Computer Science, Eindhoven University of Technology, Groene Loper 5, 5600MB Eindhoven, The Netherlands

Appl. Sci. 2017, 7(10), 1023; https://doi.org/10.3390/app7101023 - 4 Oct 2017

Cited by 23 | Viewed by 4981

Abstract

Configurable process models are frequently used to represent business workflows and other discrete event systems among different branches of large organizations: they unify commonalities shared by all branches and describe their differences, at the same time. The configuration of such models is usually [...] Read more.

Configurable process models are frequently used to represent business workflows and other discrete event systems among different branches of large organizations: they unify commonalities shared by all branches and describe their differences, at the same time. The configuration of such models is usually done manually, which is challenging. On the one hand, when the number of configurable nodes in the configurable process model grows, the size of the search space increases exponentially. On the other hand, the person performing the configuration may lack the holistic perspective to make the right choice for all configurable nodes at the same time, since choices influence each other. Nowadays, information systems that support the execution of business processes create event data reflecting how processes are performed. In this article, we propose three strategies (based on exhaustive search, genetic algorithms and a greedy heuristic) that use event data to automatically derive a process model from a configurable process model that better represents the characteristics of the process in a specific branch. These strategies have been implemented in our proposed framework and tested in both business-like event logs as recorded in a higher educational enterprise resource planning system and a real case scenario involving a set of Dutch municipalities. Full article

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

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12 pages, 2532 KiB

Open AccessFeature PaperArticle

Modelling and numerical simulation of Supercritical CO2 debinding of Inconel 718 components elaborated by Metal Injection Molding

by Aboubakry Agne^* and Thierry Barrière

Femto-ST Institute, 24 rue de l’épitaphe, 25000 Besançon, France

Appl. Sci. 2017, 7(10), 1024; https://doi.org/10.3390/app7101024 - 6 Oct 2017

Cited by 10 | Viewed by 5441

Abstract

A debinding step using the supercritical state of a fluid has been increasingly investigated for extracting organic binders from components obtained by metal-injection molding. It consists of placing the component in an enclosure subjected to pressure and temperatures higher than the critical point [...] Read more.

A debinding step using the supercritical state of a fluid has been increasingly investigated for extracting organic binders from components obtained by metal-injection molding. It consists of placing the component in an enclosure subjected to pressure and temperatures higher than the critical point to perform polymer extraction of the Metal-injection molding (MIM) component. It is an alternative to conventional solvent debinding. The topic of this study is to model and simulate the supercritical debinding stage to elucidate the mechanism of polymer degradation and stabilization with a three-dimensional model. Modelling this extraction process would optimize the process on an industrial scale. It can be physically described by Fick’s law of diffusion. The model’s main parameter is the diffusion coefficient, which is identified by using linear regression based on the least-squares method. In the model, an effective length scale is specially developed to take into account the diffusion in all directions. The tests were performed for extracting polyethylene glycol, an organic additive, using supercritical CO2 in injected components. The feedstock is composed of polypropylene, polyethylene glycol, and stearic-acid as binder mixed with Inconel 718 super-alloy powders. The identified parameters were used to calculate the diffusion coefficient and simulate the supercritical debinding step on the Comsol Multiphysics® finite-element software platform to predict the remaining binder. The obtained numerical simulation results are in good agreement with the experimental data. The proposed numerical simulations allow for the determination of the remaining polyethylene glycol (PEG) binder distribution with respect to processing parameters for components during the supercritical debinding process at any time. Moreover, this approach can be used in other formulation, powder, and binder systems. Full article

(This article belongs to the Special Issue Powder Injection Moulding)

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17 pages, 1982 KiB

Open AccessArticle

Fault Diagnosis of a Reconfigurable Crawling–Rolling Robot Based on Support Vector Machines

by Karthikeyan Elangovan^1,*, Yokhesh Krishnasamy Tamilselvam², Rajesh Elara Mohan^3,*, Masami Iwase⁴, Nemoto Takuma¹ and Kristin L. Wood³

¹ Temasek Lab, Singapore University of Technology and Design, Singapore 487372, Singapore

² Department of Electrical and Computer Engineering, Clemson University, Clemson, SC 29634, USA

³ Engineering Product Development Pillar, Singapore University of Technology and Design, Singapore 487372, Singapore

⁴ Department of Robotics and Mechatronics, Tokyo Denki University, Tokyo 120-8551, Japan

Appl. Sci. 2017, 7(10), 1025; https://doi.org/10.3390/app7101025 - 6 Oct 2017

Cited by 32 | Viewed by 5435

Abstract

As robots begin to perform jobs autonomously, with minimal or no human intervention, a new challenge arises: robots also need to autonomously detect errors and recover from faults. In this paper, we present a Support Vector Machine (SVM)-based fault diagnosis system for a [...] Read more.

As robots begin to perform jobs autonomously, with minimal or no human intervention, a new challenge arises: robots also need to autonomously detect errors and recover from faults. In this paper, we present a Support Vector Machine (SVM)-based fault diagnosis system for a bio-inspired reconfigurable robot named Scorpio. The diagnosis system needs to detect and classify faults while Scorpio uses its crawling and rolling locomotion modes. Specifically, we classify between faulty and non-faulty conditions by analyzing onboard Inertial Measurement Unit (IMU) sensor data. The data capture nine different locomotion gaits, which include rolling and crawling modes, at three different speeds. Statistical methods are applied to extract features and to reduce the dimensionality of original IMU sensor data features. These statistical features were given as inputs for training and testing. Additionally, the c-Support Vector Classification (c-SVC) and nu-SVC models of SVM, and their fault classification accuracies, were compared. The results show that the proposed SVM approach can be used to autonomously diagnose locomotion gait faults while the reconfigurable robot is in operation. Full article

(This article belongs to the Section Mechanical Engineering)

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15 pages, 3100 KiB

Open AccessArticle

Analysis of Powertrain Loading Dynamic Characteristics and the Effects on Fatigue Damage

by Jinyang Bai¹

, Xuelei Wu², Feng Gao^1,* and Hongbiao Li²

¹ School of Transportation Science and Engineering, Beihang University, Beijing 100191, China

² Beijing Institute of Space Launch Technology, Beijing 100076, China

Appl. Sci. 2017, 7(10), 1027; https://doi.org/10.3390/app7101027 - 6 Oct 2017

Cited by 14 | Viewed by 5333

Abstract

The objective of this study is to investigate the effects of key factors on the powertrain loading dynamic characteristics and fatigue damage. First, the engine and the transmission output shaft torque of a multi-axle vehicle powertrain system were measured by proving grounds (PG) [...] Read more.

The objective of this study is to investigate the effects of key factors on the powertrain loading dynamic characteristics and fatigue damage. First, the engine and the transmission output shaft torque of a multi-axle vehicle powertrain system were measured by proving grounds (PG) testing and analyzed with a conclusion that the powertrain loading changes were mainly related to three key factors: the mean engine torque, the harmonic engine torque, and the vibration properties of the system. Subsequently, a dynamic model considering the three factors was built and validated by the test data. Finally, fatigue damage of shaft parts and gear parts were calculated to investigate the influence degrees of the three factors. The results show that, the harmonic engine torque and the vibration properties of the powertrain system have a great influence on the fatigue damage of shaft parts, and the mean engine torque is the main factor causing the fatigue damage of gear parts. Full article

(This article belongs to the Section Mechanical Engineering)

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12 pages, 1497 KiB

Open AccessArticle

Optimal Tilt Angle and Orientation of Photovoltaic Modules Using HS Algorithm in Different Climates of China

by Mian Guo¹, Haixiang Zang^1,2,*

, Shengyu Gao³, Tingji Chen³, Jing Xiao³, Lexiang Cheng³, Zhinong Wei¹ and Guoqiang Sun¹

¹ College of Energy and Electrical Engineering, Hohai University, Nanjing 211100, China

² Jiangsu Key Laboratory of Smart Grid Technology and Equipment, Nanjing 210096, China

³ State Grid Nanjing power supply company, Nanjing 210019, China

Appl. Sci. 2017, 7(10), 1028; https://doi.org/10.3390/app7101028 - 6 Oct 2017

Cited by 50 | Viewed by 6305

Abstract

Solar energy technologies play an important role in shaping a sustainable energy future, and generating clean, renewable, and widely distributed energy sources. This paper determines the optimum tilt angle and optimum azimuth angle of photovoltaic (PV) panels, employing the harmony search (HS) meta-heuristic [...] Read more.

Solar energy technologies play an important role in shaping a sustainable energy future, and generating clean, renewable, and widely distributed energy sources. This paper determines the optimum tilt angle and optimum azimuth angle of photovoltaic (PV) panels, employing the harmony search (HS) meta-heuristic algorithm. In this study, the ergodic method is first conducted to obtain the optimum tilt angle and the optimum azimuth angle in several cities of China based on the model of Julian dating. Next, the HS algorithm is applied to search for the optimum solution. The purpose of this research is to maximize the extraterrestrial radiation on the collector surface for a specific period. The sun’s position is predicted by the proposed model at different times, and then solar radiation is obtained on various inclined planes with different orientations in each city. The performance of the HS method is compared with that of the ergodic method and other optimization algorithms. The results demonstrate that the tilt angle should be changed once a month, and the best orientation is usually due south in the selected cities. In addition, the HS algorithm is a practical and reliable alternative for estimating the optimum tilt angle and optimum azimuth angle of PV panels. Full article

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

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13 pages, 3287 KiB

Open AccessFeature PaperArticle

Evaluation of Adhesion and Hysteresis Friction of Rubber–Pavement System

by Mohammad Al-Assi^* and Emad Kassem

Department of Civil and Environmental Engineering, University of Idaho, Moscow, ID 83844, USA

Appl. Sci. 2017, 7(10), 1029; https://doi.org/10.3390/app7101029 - 7 Oct 2017

Cited by 44 | Viewed by 7953

Abstract

Tire-pavement friction is a key component in road safety. Adhesion and hysteresis are the two main mechanisms that affect the friction between rubber tires and pavements. This study experimentally examined the relationship between rubber–pavement adhesion and friction. The adhesive bond energy between rubber [...] Read more.

Tire-pavement friction is a key component in road safety. Adhesion and hysteresis are the two main mechanisms that affect the friction between rubber tires and pavements. This study experimentally examined the relationship between rubber–pavement adhesion and friction. The adhesive bond energy between rubber and pavement surfaces was calculated by measuring the surface energy components of rubber and aggregates. The friction was measured in the laboratory using a dynamic friction tester. The results revealed that there is a fair correlation between the adhesive bond energy and measured coefficient of friction. A rubber–pavement system with higher adhesion provided higher friction at low speed. In addition, the results demonstrated that there is a strong correlation between rubber–pavement friction and rubber properties. Softer rubber provided higher friction and vice versa. The results of this study provide an experimental verification of the relationship between adhesion and pavement surface friction. The adhesive bond energy and rubber rheological properties could be incorporated in computational models to study tire-pavement friction in different conditions (e.g., speed and temperature). Full article

(This article belongs to the Special Issue Advanced Asphalt Materials and Paving Technologies)

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30 pages, 3892 KiB

Open AccessArticle

From Point Clouds to Building Information Models: 3D Semi-Automatic Reconstruction of Indoors of Existing Buildings

by Hélène Macher^*, Tania Landes and Pierre Grussenmeyer

ICube Laboratory, Photogrammetry and Geomatics Group, National Institute of Applied Sciences (INSA),24 Boulevard de la Victoire, 67084 Strasbourg CEDEX, France

Appl. Sci. 2017, 7(10), 1030; https://doi.org/10.3390/app7101030 - 12 Oct 2017

Cited by 243 | Viewed by 16072

Abstract

The creation of as-built Building Information Models requires the acquisition of the as-is state of existing buildings. Laser scanners are widely used to achieve this goal since they permit to collect information about object geometry in form of point clouds and provide a [...] Read more.

The creation of as-built Building Information Models requires the acquisition of the as-is state of existing buildings. Laser scanners are widely used to achieve this goal since they permit to collect information about object geometry in form of point clouds and provide a large amount of accurate data in a very fast way and with a high level of details. Unfortunately, the scan-to-BIM (Building Information Model) process remains currently largely a manual process which is time consuming and error-prone. In this paper, a semi-automatic approach is presented for the 3D reconstruction of indoors of existing buildings from point clouds. Several segmentations are performed so that point clouds corresponding to grounds, ceilings and walls are extracted. Based on these point clouds, walls and slabs of buildings are reconstructed and described in the IFC format in order to be integrated into BIM software. The assessment of the approach is proposed thanks to two datasets. The evaluation items are the degree of automation, the transferability of the approach and the geometric quality of results of the 3D reconstruction. Additionally, quality indexes are introduced to inspect the results in order to be able to detect potential errors of reconstruction. Full article

(This article belongs to the Special Issue Laser Scanning)

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13 pages, 4517 KiB

Open AccessArticle

Modeling Coloration of a Radiochromic Film with Molecular Dynamics-Coupled Finite Element Method

by Mehrdad Shahmohammadi Beni¹, D. Krstic², D. Nikezic^1,2 and K.N. Yu^1,*

¹ Department of Physics, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, China

² Faculty of Science, University of Kragujevac, Kragujevac 34000, Serbia

Appl. Sci. 2017, 7(10), 1031; https://doi.org/10.3390/app7101031 - 7 Oct 2017

Cited by 2 | Viewed by 4095

Abstract

Radiochromic films change color upon exposures to radiation doses as a result of solid-state polymerization (SSP). Commercially available radiochromic films are primarily designed for, and have become widely used in, clinical X-ray dosimetry. However, many intriguing properties of radiochromic films are not yet [...] Read more.

Radiochromic films change color upon exposures to radiation doses as a result of solid-state polymerization (SSP). Commercially available radiochromic films are primarily designed for, and have become widely used in, clinical X-ray dosimetry. However, many intriguing properties of radiochromic films are not yet fully understood. The present work aimed at developing a theoretical model at both atomic and macroscopic scales to provide a platform for future works to understand these intriguing properties. Despite the fact that radiochromic films were primarily designed for clinical X-ray dosimetry, dose-response curves for the Gafchromic EBT3 film obtained for ultraviolet (UV) radiation were employed to develop our model in order to avoid complications of ionization, non-uniform energy deposition, as well as dispersed doses caused by secondary electrons set in motion by the indirectly ionizing X-ray photons, which might introduce added uncertainties to the model and overshadow the basic SSP processes. The active layer in the EBT3 film consisted of diacetylene (DA) pentacosa-10,12-diynoate monomers, which were modelled using molecular dynamics (MD). The degrees of SSP in the atomic scale upon different UV exposures were obtained to determine the absorption coefficients of the active layer, which were then input into the finite element method (FEM). The classical steady-state Helmholtz equation was engaged to model the reflection from the active layer using the FEM technique. The multifrontal massively parallel sparse direct solver (MUMPS) was employed to solve the present numerical problem. Very good agreement between experimentally and theoretically obtained coloration in terms of net reflective optical density was achieved for different UV exposures. In particular, for UV exposures larger than ~40 J/cm², the reflected light intensity decreased at a lower rate when compared to other UV exposure values, which was explained by the densely cross-linked structure under near-complete polymerization, and thus the lower efficiency for further bond formation between DA monomer strands. Full article

(This article belongs to the Special Issue Radiation Effects of Materials with Laser, Ion Beam and Rays)

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8 pages, 1641 KiB

Open AccessArticle

Fast Frequency Acquisition and Phase Locking of Nonplanar Ring Oscillators

by Yunxiang Wang^*, Chen Wang, Yangping Tao, Yang Liu, Qiang Zhou

, Jun Su, Zhiyong Wang, Shuangjin Shi and Qi Qiu

School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China

Appl. Sci. 2017, 7(10), 1032; https://doi.org/10.3390/app7101032 - 9 Oct 2017

Cited by 5 | Viewed by 4160

Abstract

Optical phase locking is a critical technique in space coherent optical communication and active coherent laser beam combining. In a typical optical phase locking loop based on nonplanar ring oscillators, the pull-in range is normally less than 1 MHz, limited by loop delay [...] Read more.

Optical phase locking is a critical technique in space coherent optical communication and active coherent laser beam combining. In a typical optical phase locking loop based on nonplanar ring oscillators, the pull-in range is normally less than 1 MHz, limited by loop delay and frequency tuning bandwidth of the laser source. Phase locking cannot be achieved at large initial frequency differences. In this work, a fast laser frequency acquisition method is demonstrated. The frequency difference between the signal and local lasers was measured via frequency dividing and period counting, and the frequency control signal was generated by a frequency discrimination and control module, to reduce the frequency difference to the pull-in range of the loop. Under the coordinating function of the loop filter and the frequency discrimination and control module, phase locking under a large initial frequency difference was achieved. The frequency acquisition range reached 164 MHz, and the acquisition and locking time was measured to be 440 ms. Additionally, the acquisition time was shortened with the decrease in initial frequency difference. Full article

(This article belongs to the Special Issue Solid State Lasers Materials, Technologies and Applications)

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15 pages, 2765 KiB

Open AccessArticle

Fast Reconfigurable SOA-Based Wavelength Conversion of Advanced Modulation Format Data

by Yi Lin^1,*, Aravind P. Anthur¹, Sean P. Ó Dúill¹

, Fan Liu², Yonglin Yu² and Liam P. Barry¹

¹ School of Electronic Engineering, Dublin City University, Dublin 9, Ireland

² Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430073, China

Appl. Sci. 2017, 7(10), 1033; https://doi.org/10.3390/app7101033 - 10 Oct 2017

Cited by 5 | Viewed by 5363

Abstract

We theoretically analyze the phase noise transfer issue between the pump and the wavelength-converted idler for a nondegenerate four-wave mixing (FWM) scheme, as well as study the vector theory in nonlinear semiconductor optical amplifiers (SOAs), in order to design a polarization-insensitive wavelength conversion [...] Read more.

We theoretically analyze the phase noise transfer issue between the pump and the wavelength-converted idler for a nondegenerate four-wave mixing (FWM) scheme, as well as study the vector theory in nonlinear semiconductor optical amplifiers (SOAs), in order to design a polarization-insensitive wavelength conversion system employing dual co-polarized pumps. A tunable sampled grating distributed Bragg reflector (SG-DBR) pump laser has been utilized to enable fast wavelength conversion in the sub-microsecond timescale. By using the detailed characterization of the SGDBR laser, we discuss the phase noise performance of the SGDBR laser. Finally, we present a reconfigurable SOA-based all-optical wavelength converter using the fast switching SGDBR tunable laser as one of the pump sources and experimentally study the wavelength conversion of the single polarization quadrature phase shift keying (QPSK) and polarization multiplexed (Pol-Mux) QPSK signals at 12.5-Gbaud. A wide tuning range (>10 nm) and less than 50 ns and 160 ns reconfiguration time have been achieved for the wavelength conversion system for QPSK and PM-QPSK signals, respectively. The performance under the switching environment after the required reconfiguration time is the same as the static case when the wavelengths are fixed. Full article

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

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20 pages, 6874 KiB

Open AccessArticle

Communication Architecture for Grid Integration of Cyber Physical Wind Energy Systems

by Mohamed A. Ahmed^1,2

and Chul-Hwan Kim^1,*

¹ College of Information and Communication Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 16419, Korea

² Department of Communications and Electronics, Higher Institute of Engineering and Technology-King Marriott, Alexandria 23713, Egypt

Appl. Sci. 2017, 7(10), 1034; https://doi.org/10.3390/app7101034 - 10 Oct 2017

Cited by 8 | Viewed by 8918

Abstract

As we move toward increasing the grid integration of large-scale wind farms (WFs), reliable monitoring, protection, and control are needed to ensure grid stability. WFs are considered to be large and complex cyber physical systems owing to coupling between the electric power system [...] Read more.

As we move toward increasing the grid integration of large-scale wind farms (WFs), reliable monitoring, protection, and control are needed to ensure grid stability. WFs are considered to be large and complex cyber physical systems owing to coupling between the electric power system and information and communication technologies (ICT). In this study, we proposed a framework for a cyber physical wind energy system (CPWES), which consists of four layers: a WF power system layer, data acquisition and monitoring layer, communication network layer, and application layer. We performed detailed network modeling for the WF system, including the wind turbines, meteorological mast (met-mast), and substation based on IEC 61400-25 and IEC 61850 standards. Network parameters and configuration were based on a real WF (Korean Southwest offshore project). The simulation results of the end-to-end delay were obtained for different WF applications, and they were compared with the timing requirements of the IEC 1646 standard. The proposed architecture represents a reference model for WF systems, and it can be used to enable the design of future CPWESs. Full article

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

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20 pages, 7557 KiB

Open AccessArticle

Parameters Sensitivity Analysis of Position-Based Impedance Control for Bionic Legged Robots’ HDU

by Kaixian Ba¹, Bin Yu^1,2,*, Zhengjie Gao¹, Wenfeng Li¹, Guoliang Ma¹ and Xiangdong Kong^1,2,3

¹ School of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, China

² Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control, Qinhuangdao, China

³ National Engineering Research Center for Local Joint of Advanced Manufacturing Technology and Equipment, Yanshan University, Qinhuangdao 066004, China

Appl. Sci. 2017, 7(10), 1035; https://doi.org/10.3390/app7101035 - 10 Oct 2017

Cited by 25 | Viewed by 5829

Abstract

For the hydraulic drive unit (HDU) on the joints of bionic legged robots, this paper proposes the position-based impedance control method. Then, the impedance control performance is tested by a HDU performance test platform. Further, the method of first-order sensitivity matrix is proposed [...] Read more.

For the hydraulic drive unit (HDU) on the joints of bionic legged robots, this paper proposes the position-based impedance control method. Then, the impedance control performance is tested by a HDU performance test platform. Further, the method of first-order sensitivity matrix is proposed to analyze the dynamic sensitivity of four main control parameters under four working conditions. To research the parameter sensitivity quantificationally, two sensitivity indexes are defined, and the sensitivity analysis results are verified by experiments. The results of the experiments show that, when combined with corresponding optimization strategies, the dynamic compliance composition theory and the results from sensitivity analysis can compensate for the control parameters and optimize the control performance in different working conditions. Full article

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

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11 pages, 3940 KiB

Open AccessArticle

Macroporous Activated Carbon Derived from Rapeseed Shell for Lithium–Sulfur Batteries

by Mingbo Zheng^*, Qin Hu, Songtao Zhang, Hao Tang, Lulu Li and Huan Pang^*

School of Chemistry and Chemical Engineering, Institute for Innovative Materials and Energy, Yangzhou University, Yangzhou 225009, Jiangsu, China

Appl. Sci. 2017, 7(10), 1036; https://doi.org/10.3390/app7101036 - 10 Oct 2017

Cited by 39 | Viewed by 8027

Abstract

Lithium–sulfur batteries have drawn considerable attention because of their extremely high energy density. Activated carbon (AC) is an ideal matrix for sulfur because of its high specific surface area, large pore volume, small-size nanopores, and simple preparation. In this work, through KOH activation, [...] Read more.

Lithium–sulfur batteries have drawn considerable attention because of their extremely high energy density. Activated carbon (AC) is an ideal matrix for sulfur because of its high specific surface area, large pore volume, small-size nanopores, and simple preparation. In this work, through KOH activation, AC materials with different porous structure parameters were prepared using waste rapeseed shells as precursors. Effects of KOH amount, activated temperature, and activated time on pore structure parameters of ACs were studied. AC sample with optimal pore structure parameters was investigated as sulfur host materials. Applied in lithium–sulfur batteries, the AC/S composite (60 wt % sulfur) exhibited a high specific capacity of 1065 mAh g⁻¹ at 200 mA g⁻¹ and a good capacity retention of 49% after 1000 cycles at 1600 mA g⁻¹. The key factor for good cycling stability involves the restraining effect of small-sized nanopores of the AC framework on the diffusion of polysulfides to bulk electrolyte and the loss of the active material sulfur. Results demonstrated that AC materials derived from rapeseed shells are promising materials for sulfur loading. Full article

(This article belongs to the Special Issue Electrode Materials for Lithium-ion Batteries/Super-capacitors)

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21 pages, 2773 KiB

Open AccessArticle

An Integrated Risk Index Model Based on Hierarchical Fuzzy Logic for Underground Risk Assessment

by Muhammad Fayaz¹, Israr Ullah¹, Dong-Hwan Park², Kwangsoo Kim² and DoHyeun Kim^1,*

¹ Department of Computer Engineering, Jeju National University, Jeju 63243, Korea

² ETRI, 218 Gajenong-ro Yuseung-Gu, Daejeon 34129, Korea

Appl. Sci. 2017, 7(10), 1037; https://doi.org/10.3390/app7101037 - 11 Oct 2017

Cited by 25 | Viewed by 5092

Abstract

Available space in congested cities is getting scarce due to growing urbanization in the recent past. The utilization of underground space is considered as a solution to the limited space in smart cities. The numbers of underground facilities are growing day by day [...] Read more.

Available space in congested cities is getting scarce due to growing urbanization in the recent past. The utilization of underground space is considered as a solution to the limited space in smart cities. The numbers of underground facilities are growing day by day in the developing world. Typical underground facilities include the transit subway, parking lots, electric lines, water supply and sewer lines. The likelihood of the occurrence of accidents due to underground facilities is a random phenomenon. To avoid any accidental loss, a risk assessment method is required to conduct the continuous risk assessment and report any abnormality before it happens. In this paper, we have proposed a hierarchical fuzzy inference based model for under-ground risk assessment. The proposed hierarchical fuzzy inference architecture reduces the total number of rules from the rule base. Rule reduction is important because the curse of dimensionality damages the transparency and interpretation as it is very tough to understand and justify hundreds or thousands of fuzzy rules. The computation time also increases as rules increase. The proposed model takes 175 rules having eight input parameters to compute the risk index, and the conventional fuzzy logic requires 390,625 rules, having the same number of input parameters to compute risk index. Hence, the proposed model significantly reduces the curse of dimensionality. Rule design for fuzzy logic is also a tedious task. In this paper, we have also introduced new rule schemes, namely maximum rule-based and average rule-based; both schemes can be used interchangeably according to the logic needed for rule design. The experimental results show that the proposed method is a virtuous choice for risk index calculation where the numbers of variables are greater. Full article

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11 pages, 749 KiB

Open AccessArticle

Deterministic and Robust Optimization Approach for Single Artillery Unit Fire Scheduling Problem

by Yong Baek Choi, Suk Ho Jin and Kyung Sup Kim^*

Department of Industrial Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea

Appl. Sci. 2017, 7(10), 1038; https://doi.org/10.3390/app7101038 - 11 Oct 2017

Cited by 4 | Viewed by 3813

Abstract

In this study, deterministic and robust optimization models for single artillery unit fire scheduling are developed to minimize the total enemy threat to friendly forces by considering the enemy target threat level, enemy target destruction time, and target firing preparation time simultaneously. Many [...] Read more.

In this study, deterministic and robust optimization models for single artillery unit fire scheduling are developed to minimize the total enemy threat to friendly forces by considering the enemy target threat level, enemy target destruction time, and target firing preparation time simultaneously. Many factors in war environments are uncertain. In particular, it is difficult to evaluate the threat levels of enemy targets definitively. We consider the threat level of an enemy target to be an uncertain parameter and propose a robust optimization model that minimizes the total enemy threat to friendly forces. The robust optimization model represents a semi-infinite problem that has infinitely many constraints. Therefore, we reformulate the robust optimization model into a tractable robust counterpart formulation with a finite number of constraints. In the robust counterpart formulation with cardinality-constrained uncertainty, the conservativeness and robustness of the solution can be adjusted with an uncertainty degree, Γ. Further, numerical experiments are conducted to verify that the robust counterpart formulation with cardinality-constrained uncertainty can be made equivalent to the deterministic optimization model and the robust counterpart formulation with box uncertainty by setting Γ accordingly. Full article

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

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18 pages, 3326 KiB

Open AccessArticle

A Kriging Model Based Finite Element Model Updating Method for Damage Detection

by Xiuming Yang¹, Xinglin Guo^1,*, Huajiang Ouyang^1,2 and Dongsheng Li³

¹ Department of Engineering Mechanics, State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116000, China

² School of Engineering, University of Liverpool, Liverpool L69 3BX, UK

³ School of Civil Engineering, Dalian University of Technology, Dalian 116000, China

Appl. Sci. 2017, 7(10), 1039; https://doi.org/10.3390/app7101039 - 11 Oct 2017

Cited by 37 | Viewed by 6752

Abstract

Model updating is an effective means of damage identification and surrogate modeling has attracted considerable attention for saving computational cost in finite element (FE) model updating, especially for large-scale structures. In this context, a surrogate model of frequency is normally constructed for damage [...] Read more.

Model updating is an effective means of damage identification and surrogate modeling has attracted considerable attention for saving computational cost in finite element (FE) model updating, especially for large-scale structures. In this context, a surrogate model of frequency is normally constructed for damage identification, while the frequency response function (FRF) is rarely used as it usually changes dramatically with updating parameters. This paper presents a new surrogate model based model updating method taking advantage of the measured FRFs. The Frequency Domain Assurance Criterion (FDAC) is used to build the objective function, whose nonlinear response surface is constructed by the Kriging model. Then, the efficient global optimization (EGO) algorithm is introduced to get the model updating results. The proposed method has good accuracy and robustness, which have been verified by a numerical simulation of a cantilever and experimental test data of a laboratory three-story structure. Full article

(This article belongs to the Section Mechanical Engineering)

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16 pages, 4786 KiB

Open AccessArticle

Pipeline Damage Identification Based on Additional Virtual Masses

by Dongsheng Li^*, Dang Lu and Jilin Hou

Institute of Intelligent Structural Systems, School of Civil Engineering, Dalian University of Technology, Dalian 116024, China

Appl. Sci. 2017, 7(10), 1040; https://doi.org/10.3390/app7101040 - 11 Oct 2017

Cited by 8 | Viewed by 3372

Abstract

To improve the identification sensitivity of local damages in pipelines, we propose an added virtual mass method thatprevents adding real masses to the pipeline. First, we develop a method of adding virtual masses to pipelines based on the virtual distortion method (VDM). Second, [...] Read more.

To improve the identification sensitivity of local damages in pipelines, we propose an added virtual mass method thatprevents adding real masses to the pipeline. First, we develop a method of adding virtual masses to pipelines based on the virtual distortion method (VDM). Second, a frequency response to the added mass is constructed using the excitation and acceleration responses. The quantity of mass and the corresponding selected natural frequency with high sensitivity are both determined by the analyzing the sensitivity of the relationship between mass and natural frequency. Finally, the degree of damage can be accurately identified by adding virtual masses on the substructure of the pipeline combined with sensitivity and frequency. Using numerical simulations and experiments, we verify the feasibility of the added virtual mass method for the identification of damages to pipeline structures. Full article

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9 pages, 11862 KiB

Open AccessArticle

Interactions of Insolation and Shading on Ability to Use Fluorescence Imaging to Detect Fecal Contaminated Spinach

by Alan M. Lefcourt^1,* and Mark C. Siemens²

¹ USDA (United States Department of Agriculture) Agricultural Research Service, Rm 21, Bldg 303, BARC-East, Powder Mill Rd., Beltsville, MD 20705, USA

² Department of Agricultural and Biosystems Engineering, Yuma Agricultural Center, University of Arizona, 6425 W. 8th St., Yuma, AZ 85364, USA

Appl. Sci. 2017, 7(10), 1041; https://doi.org/10.3390/app7101041 - 12 Oct 2017

Cited by 4 | Viewed by 3457

Abstract

Fecal contamination of produce in fields is a recognized food safety risk, and it is a requirement that fields be surveyed for evidence of fecal contamination. It may be possible to increase the efficacy of such surveys using imaging techniques that rely on [...] Read more.

Fecal contamination of produce in fields is a recognized food safety risk, and it is a requirement that fields be surveyed for evidence of fecal contamination. It may be possible to increase the efficacy of such surveys using imaging techniques that rely on detection of fluorescence responses of fecal material to UV excitation. However, fluorescence responses are easily masked by ambient illumination. This study investigated the potential of using a shroud to reduce the impact of ambient illumination on responses measured using relatively inexpensive optical components. During periods of near peak insolation, even with full shrouding, results indicate that reliable detection would be problematic. Towards dusk, effective imaging could be accomplished even with a gap of 250 cm at the bottom of the shroud. Results suggest that imaging using relatively inexpensive components could provide the basis for detection of fecal contamination in produce fields if surveys were conducted during dawn or dusk, or at night. Full article

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

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16 pages, 1054 KiB

Open AccessArticle

Obstacle Avoidance with Potential Field Applied to a Rendezvous Maneuver

by Nicoletta Bloise¹, Elisa Capello^1,2,*, Matteo Dentis¹ and Elisabetta Punta²

¹ Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy

² National Council of Research, Institute of Electronics, Computer and Telecommunication Engineering (CNR–IEIIT), Corso Duca degli Abruzzi 24, 10129 Torino, Italy

Appl. Sci. 2017, 7(10), 1042; https://doi.org/10.3390/app7101042 - 12 Oct 2017

Cited by 23 | Viewed by 5226

Abstract

This paper outlines a method based on the theory of artificial potential fields combined with sliding mode techniques for spacecraft maneuvers in the presence of obstacles. Guidance and control algorithms are validated with a six degree-of-freed (dof) omorbital simulator. The idea of this [...] Read more.

This paper outlines a method based on the theory of artificial potential fields combined with sliding mode techniques for spacecraft maneuvers in the presence of obstacles. Guidance and control algorithms are validated with a six degree-of-freed (dof) omorbital simulator. The idea of this paper is to provide computationally efficient algorithms for real time applications, in which the combination of Artificial potential field (APF) and sliding mode control shows the ability of plan trajectories, even in the presence of external disturbances and model uncertainties. A reduced frequency of the proposed controllers and a pulse width modulation (PWM) of the thrusters are considered to verify the performance of the system. The computational performance of APF as a guidance algorithm is discussed and the algorithms are verified by simulations of a complete rendezvous maneuver. The proposed algorithm appears suitable for the autonomous, real-time control of complex maneuvers with a minimum on-board computational effort. Full article

(This article belongs to the Section Mechanical Engineering)

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11 pages, 5392 KiB

Open AccessArticle

Synthesis and Thermoelectric Properties of TiO₂/Cu₂SnSe₃ Composites

by Jiai Ning, Di Wu and Degang Zhao^*

School of Materials Science and Engineering, University of Jinan, Jinan 250022, China

Appl. Sci. 2017, 7(10), 1043; https://doi.org/10.3390/app7101043 - 12 Oct 2017

Cited by 20 | Viewed by 5602

Abstract

Thermoelectric (TE) materials are a kind of energy material which can directly convert waste heat into electricity based on TE effects. Ternary Cu₂SnSe₃ material with diamond-like structure has become one of the potential TE materials due to its low thermal [...] Read more.

Thermoelectric (TE) materials are a kind of energy material which can directly convert waste heat into electricity based on TE effects. Ternary Cu₂SnSe₃ material with diamond-like structure has become one of the potential TE materials due to its low thermal conductivity and adjustable electrical conductivity. In this study, the Cu₂SnSe₃ powder was prepared by vacuum melting-quenching-annealing-grinding process. The nano-TiO₂ particles were introduced into the Cu₂SnSe₃ matrix by ball milling. Spark plasma sintering (SPS) was employed to fabricate the TiO₂/Cu₂SnSe₃ composites. The X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM) were used to study the phase and microstructure of TiO₂/Cu₂SnSe₃ composites. Electrical resistivity, Seebeck coefficient, and thermal conductivity measurement were applied to analyze the thermoelectric properties. For the 1.4%TiO₂/Cu₂SnSe₃ composite, the electrical conductivity was improved whereas the Seebeck coefficient was lower than that of pure Cu₂SnSe₃. For other TiO₂/Cu₂SnSe₃ samples, the Seebeck coefficient was improved while the electrical conductivity was reduced. The thermal conductivity of TiO₂/Cu₂SnSe₃ composites was lower than that of Cu₂SnSe₃ matrix, which is attributed to the lower carrier conductivity. A maximum ZT of 0.30 at 700 K for the 1.0%TiO₂/Cu₂SnSe₃ composite was obtained, which was 17% higher than that of the pure Cu₂SnSe₃ at 700 K. Full article

(This article belongs to the Special Issue Recent Progress in the Development of Thermoelectric Materials)

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23 pages, 5746 KiB

Open AccessArticle

Soil–Structure–Equipment Interaction and Influence Factors in an Underground Electrical Substation under Seismic Loads

by Bo Wen^1,*

, Lu Zhang¹, Ditao Niu¹ and Muhua Zhang²

¹ School of Civil Engineering, Xi’an University of Architecture & Technology, Xi’an 710055, China

² School of Humanities, Xi’an Polytechnic University, Xi’an 710048, China

Appl. Sci. 2017, 7(10), 1044; https://doi.org/10.3390/app7101044 - 12 Oct 2017

Cited by 7 | Viewed by 4899

Abstract

Underground electrical substations play an increasingly significant role in urban economic development for the power supply of subways. However, in recent years, there have been few studies on the seismic performance of underground electrical substations involving the interaction of soil–structure–equipment. To conduct the [...] Read more.

Underground electrical substations play an increasingly significant role in urban economic development for the power supply of subways. However, in recent years, there have been few studies on the seismic performance of underground electrical substations involving the interaction of soil–structure–equipment. To conduct the study, three-dimensional finite element models of an underground substation are established. The implicit dynamic numerical simulation analysis is performed by changing earthquake input motions, soil characteristics, electrical equipment type and structure depths. According to a seismic response analysis, acceleration amplification coefficients, displacements, stresses and internal forces are obtained and analyzed. It is found that (1) as a boundary condition of soil–structure, the coupling boundary is feasible in the seismic response of an underground substation; (2) the seismic response of an underground substation is sensitive to burial depth and elastic modulus; (3) the oblique incidence of input motion has a slight influence on the horizontal seismic response, but has a significant impact on the vertical seismic response; and (4) the bottom of the side wall is the seismic weak part of an underground substation, so it is necessary to increase the stiffness of this area. Full article

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

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8 pages, 1148 KiB

Open AccessArticle

Enhanced Emission by Accumulated Charges at Organic/Metal Interfaces Generated during the Reverse Bias of Organic Light Emitting Diodes

by Soichiro Nozoe and Masaki Matsuda^*

Department of Chemistry, Kumamoto University, Kumamoto, Kumamoto 860-8555, Japan

Appl. Sci. 2017, 7(10), 1045; https://doi.org/10.3390/app7101045 - 12 Oct 2017

Cited by 6 | Viewed by 3458

Abstract

A high frequency rectangular alternating voltage was applied to organic light emitting diodes (OLEDs) with the structure ITO/TPD/Alq₃/Al and ITO/CoPc/Alq₃/Al, where ITO is indium-tin-oxide, TPD is 4,4′-bis[N-phenyl-N-(m-tolyl)amino]biphenyl, CoPc is cobalt phthalocyanine, and Alq₃ is [...] Read more.

A high frequency rectangular alternating voltage was applied to organic light emitting diodes (OLEDs) with the structure ITO/TPD/Alq₃/Al and ITO/CoPc/Alq₃/Al, where ITO is indium-tin-oxide, TPD is 4,4′-bis[N-phenyl-N-(m-tolyl)amino]biphenyl, CoPc is cobalt phthalocyanine, and Alq₃ is Tris(8-quinolinolato)aluminum, and the effect on emission of the reverse bias was examined. The results reveal that the emission intensity under an alternating reverse-forward bias is greater than that under an alternating zero-forward bias. The difference in the emission intensity (∆I) increased both for decreasing frequency and increasing voltage level of the reverse bias. In particular, the change in emission intensity was proportional to the voltage level of the reverse bias given the same frequency. To understand ΔI, this paper proposes a model in which an OLED works as a capacitor under reverse bias, where positive and negative charges accumulate on the metal/organic interfaces. In this model, the emission enhancement that occurs during the alternating reverse-forward bias is rationalized as a result of the charge accumulation at the organic/metal interfaces during the reverse bias, which possibly modulates the vacuum level shifts at the organic/metal interfaces to reduce both the hole injection barrier at the organic/ITO interface and the electron injection barrier at the organic/Al interface under forward bias. Full article

(This article belongs to the Special Issue Fluorescence and Phosphorescence in Organic Materials: from Fundamental to OLED Devices)

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13 pages, 7988 KiB

Open AccessArticle

Classification of Forest Vertical Structure in South Korea from Aerial Orthophoto and Lidar Data Using an Artificial Neural Network

by Soo-Kyung Kwon, Hyung-Sup Jung^*

, Won-Kyung Baek and Daeseong Kim

Department of Geoinformatics, University of Seoul, Seoul 02504, Korea

Appl. Sci. 2017, 7(10), 1046; https://doi.org/10.3390/app7101046 - 12 Oct 2017

Cited by 29 | Viewed by 7195

Abstract

Every vegetation colony has its own vertical structure. Forest vertical structure is considered as an important indicator of a forest’s diversity and vitality. The vertical structure of a forest has typically been investigated by field survey, which is the traditional method of forest [...] Read more.

Every vegetation colony has its own vertical structure. Forest vertical structure is considered as an important indicator of a forest’s diversity and vitality. The vertical structure of a forest has typically been investigated by field survey, which is the traditional method of forest inventory. However, this method is very time- and cost-consuming due to poor accessibility. Remote sensing data such as satellite imagery, aerial photography, and lidar data can be a viable alternative to the traditional field-based forestry survey. In this study, we classified forest vertical structures from red-green-blue (RGB) aerial orthophotos and lidar data using an artificial neural network (ANN), which is a powerful machine learning technique. The test site was Gongju province in South Korea, which contains single-, double-, and triple-layered forest structures. The performance of the proposed method was evaluated by comparing the results with field survey data. The overall accuracy achieved was about 70%. It means that the proposed approach can classify the forest vertical structures from the aerial orthophotos and lidar data. Full article

(This article belongs to the Special Issue Application of Artificial Neural Networks in Geoinformatics)

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12 pages, 2440 KiB

Open AccessFeature PaperArticle

3D Suspended Polymeric Microfluidics (SPMF³) with Flow Orthogonal to Bending (FOB) for Fluid Analysis through Kinematic Viscosity

by Mostapha Marzban^1,2, Muthukumaran Packirisamy^1,*

and Javad Dargahi²

¹ Optical-Bio Microsystems Lab., Department of Mechanical and Industrial Engineering, Concordia University, Montreal, QC H3G 1M8, Canada

² Robotic Assisted Minimally Invasive Surgery Lab., Department of Mechanical and Industrial Engineering, Concordia University, Montreal, QC H3G 1M8, Canada

Appl. Sci. 2017, 7(10), 1048; https://doi.org/10.3390/app7101048 - 13 Oct 2017

Cited by 10 | Viewed by 6993

Abstract

Measuring of fluid properties such as dynamic viscosity and density has tremendous potential for various applications from physical to biological to chemical sensing. However, it is almost impossible to affect only one of these properties, as dynamic viscosity and density are coupled. Hence, [...] Read more.

Measuring of fluid properties such as dynamic viscosity and density has tremendous potential for various applications from physical to biological to chemical sensing. However, it is almost impossible to affect only one of these properties, as dynamic viscosity and density are coupled. Hence, this paper proposes kinematic viscosity as a comprehensive parameter which can be used to study the effect of fluid properties applicable to various fluids from Newtonian fluids, such as water, to non-Newtonian fluids, such as blood. This paper also proposes an ideal microplatform, namely polymeric suspended microfluidics (SPMF³), with flow plane orthogonal to the bending plane of the structure, along with tested results of various fluids covering a wide range of engineering applications. Kinematic viscosity, also called momentum diffusivity, considers changes in both fluid intermolecular forces and molecular inertia that define dynamic viscosity and fluid density, respectively. In this study a 3D suspended polymeric microfluidic system (SPMF³) was employed to detect changes in fluid parameters such as dynamic viscosity and density during fluid processes. Using this innovative design along with theoretical and experimental results, it is shown that, in fluids, the variations of fluid density and dynamic viscosity are not easily comprehensible due to their interconnectivity. Since any change in a fluid will affect both density and dynamic viscosity, measuring both of them is necessary to identify the fluid or process status. Finally, changes in fluid properties were analyzed using simulation and experiments. The experimental results with salt-DI water solution and milk with different fat concentrations as a colloidal fluid show that kinematic viscosity is a comprehensive parameter that can identify the fluids in a unique way using the proposed microplatform. Full article

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

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11 pages, 1471 KiB

Open AccessArticle

Assessment on Stationarity of EMG Signals with Different Windows Size During Isotonic Contractions

by Nurhazimah Nazmi^1,2, Mohd Azizi Abdul Rahman^1,*

, Shin-ichiroh Yamamoto², Siti Anom Ahmad³

, MB Malarvili⁴, Saiful Amri Mazlan¹

and Hairi Zamzuri¹

¹ Advanced Vehicle System, Malaysia Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, Kuala Lumpur 54100, Malaysia

² Department of Bio-science and Engineering, College of Systems Engineering and Science, Shibaura Institute of Technology, Omiya Campus, Fukasaku 307, Saitama 337-8570, Japan

³ Malaysian Research Institute on Ageing, Universiti Putra Malaysia, 43400 Serdang, Malaysia

⁴ Department of Biotechnology and Medical Engineering, Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Skudai 81310, Malaysia

Appl. Sci. 2017, 7(10), 1050; https://doi.org/10.3390/app7101050 - 13 Oct 2017

Cited by 30 | Viewed by 10502

Abstract

In order to analyse surface electromyography (EMG) signals, it is necessary to extract the features based on a time or frequency domain. These approaches are based on the mathematical assumption of signal stationarity. Stationarity of EMG signals is thoroughly examined, especially in isotonic [...] Read more.

In order to analyse surface electromyography (EMG) signals, it is necessary to extract the features based on a time or frequency domain. These approaches are based on the mathematical assumption of signal stationarity. Stationarity of EMG signals is thoroughly examined, especially in isotonic contractions. According to research, conflicting results have been identified depending on varying window sizes. Therefore, in this study, the authors endeavoured to determine the suitable window size to analyse EMG signals during isotonic contractions utilising stationary tests, reverse arrangement (RA), and modified reverse arrangement (MRA). There were slight differences in the average percentages of signal stationarity for RA and MRA tests in 100 ms, 500 ms, and 1000 ms window sizes. However, there was none for the 200 ms window size. On average, a window size of 200 ms provided stationary information with 88.57% of EMG signals compared to other window sizes. This study also recommended the MRA test to determine EMG signals stationarity for future studies, as the performances were better in comparison to RA tests. However, the following recommendation is only valid for window sizes greater than 200 ms. For a real-time application, the size of the analysis window together with the processing time should be less than 300 ms and a window size of 200 ms is applicable for isotonic contractions. Full article

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10 pages, 404 KiB

Open AccessArticle

Dynamic Scheduling of a Semiconductor Production Line Based on a Composite Rule Set

by Yumin Ma^1,*, Fei Qiao¹, Fu Zhao^2,3 and John W. Sutherland³

¹ School of Electronical & Information Engineering, Tongji University, Shanghai 201804, China

² School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA

³ Environmental and Ecological Engineering, Purdue University, West Lafayette, IN 47907, USA

Appl. Sci. 2017, 7(10), 1052; https://doi.org/10.3390/app7101052 - 13 Oct 2017

Cited by 29 | Viewed by 5787

Abstract

Various factors and constraints should be considered when developing a manufacturing production schedule, and such a schedule is often based on rules. This paper develops a composite dispatching rule based on heuristic rules that comprehensively consider various factors in a semiconductor production line. [...] Read more.

Various factors and constraints should be considered when developing a manufacturing production schedule, and such a schedule is often based on rules. This paper develops a composite dispatching rule based on heuristic rules that comprehensively consider various factors in a semiconductor production line. The composite rule is obtained by exploring various states of a semiconductor production line (machine status, queue size, etc.), where such indicators as makespan and equipment efficiency are used to judge performance. A model of the response surface, as a function of key variables, is then developed to find the optimized parameters of a composite rule for various production states. Furthermore, dynamic scheduling of semiconductor manufacturing is studied based on support vector regression (SVR). This approach dynamically obtains a composite dispatching rule (i.e., parameters of the composite dispatching rule) that can be used to optimize production performance according to real-time production line state. Following optimization, the proposed dynamic scheduling approach is tested in a real semiconductor production line to validate the effectiveness of the proposed composite rule set. Full article

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

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20 pages, 6070 KiB

Open AccessArticle

A New Fuzzy Sliding Mode Controller with a Disturbance Estimator for Robust Vibration Control of a Semi-Active Vehicle Suspension System

by Byung-Keun Song¹, Jin-Hee An² and Seung-Bok Choi^2,*

¹ Department of Mechanical System Engineering, Incheon National University, Incheon 22212, Korea

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

Appl. Sci. 2017, 7(10), 1053; https://doi.org/10.3390/app7101053 - 13 Oct 2017

Cited by 25 | Viewed by 5471

Abstract

This paper presents a new fuzzy sliding mode controller (FSMC) to improve control performances in the presence of uncertainties related to model errors and external disturbance (UAD). As a first step, an adaptive control law is designed using Lyapunov stability analysis. The control [...] Read more.

This paper presents a new fuzzy sliding mode controller (FSMC) to improve control performances in the presence of uncertainties related to model errors and external disturbance (UAD). As a first step, an adaptive control law is designed using Lyapunov stability analysis. The control law can update control parameters of the FSMC with a disturbance estimator (DE) in which the closed-loop stability and finite-time convergence of tracking error are guaranteed. A solution for estimating the compensative quantity of the impact of UAD on a control system and a set of solutions are then presented in order to avoid the singular cases of the fuzzy-based function approximation, increase convergence ability, and reduce the calculating cost. Subsequently, the effectiveness of the proposed controller is verified through the investigation of vibration control performances of a semi-active vehicle suspension system featuring a magnetorheological damper (MRD). It is shown that the proposed controller can provide better control ability of vibration control with lower consumed power compared with two existing fuzzy sliding mode controllers. Full article

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17 pages, 4228 KiB

Open AccessArticle

A Congestion Control Strategy for Power Scale-Free Communication Network

by Min Xiang and Qinqin Qu^*

Key Laboratory of Industrial Internet of Things & Networked Control, Chongqing University of Posts and Telecommunications, Chongqing 400065, China

Appl. Sci. 2017, 7(10), 1054; https://doi.org/10.3390/app7101054 - 13 Oct 2017

Cited by 7 | Viewed by 4391

Abstract

The scale-free topology of power communication network leads to more data flow in less hub nodes, which can cause local congestion. Considering the differences of the nodes’ delivery capacity and cache capacity, an integrated routing based on the communication service classification is proposed [...] Read more.

The scale-free topology of power communication network leads to more data flow in less hub nodes, which can cause local congestion. Considering the differences of the nodes’ delivery capacity and cache capacity, an integrated routing based on the communication service classification is proposed to reduce network congestion. In the power communication network, packets can be classified as key operational services (I-level) and affairs management services (II-level). The shortest routing, which selects the path of the least hops, is adopted to transmit I-level packets. The load-balanced global dynamic routing, which uses the node’s queue length and delivery capacity to establish the cost function and chooses the path with minimal cost, is adopted to transmit II-level packets. The simulation results show that the integrated routing has a larger critical packet generation rate and can effectively reduce congestion. Full article

(This article belongs to the Special Issue Distribution Power Systems)

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21 pages, 7506 KiB

Open AccessArticle

A Novel Adaptive PID Controller with Application to Vibration Control of a Semi-Active Vehicle Seat Suspension

by Do Xuan Phu^1,2, Jin-Hee An² and Seung-Bok Choi^2,*

¹ MediRobotics Laboratory, Department of Mechatronics and Sensor System Technology, Vietnamese-German University, 820000 Binh Duong, Vietnam

² Smart Structures and Systems Laboratory, Department of Mechanical Engineering, Inha University, Incheon 402-751, Korea

Appl. Sci. 2017, 7(10), 1055; https://doi.org/10.3390/app7101055 - 13 Oct 2017

Cited by 51 | Viewed by 7150

Abstract

This work proposes a novel adaptive hybrid controller based on the sliding mode controller and H-infinity control technique, and its effectiveness is verified by implementing it in vibration control of a vehicle seat suspension featuring a magneto-rheological damper. As a first step, a [...] Read more.

This work proposes a novel adaptive hybrid controller based on the sliding mode controller and H-infinity control technique, and its effectiveness is verified by implementing it in vibration control of a vehicle seat suspension featuring a magneto-rheological damper. As a first step, a sliding surface of the sliding mode controller is established and used as a bridge to formulate the proposed controller. In this process, two matrices such as Hurwitz constants matrix are used as components of the sliding surface and H-infinity technique are adopted to achieve robust stability. Secondly, a fuzzy logic model based on the interval type 2 fuzzy model which is featured by online clustering is established and integrated to take account for external disturbances. Subsequently, a new adaptive hybrid controller is formulated with a solid proof of the robust stability. Then, the effectiveness is demonstrated by implementing the proposed hybrid controller on the vibration control of a vehicle seat suspension associated with a controllable damper. Vibration control performances are evaluated on bump and random road profiles by presenting both displacement and acceleration on the seat and the driver positions. In addition, a comparative study between the proposed and one of existing controllers is undertaken to highlight some benefits of the hybrid adaptive controller developed in this work. Full article

(This article belongs to the Section Mechanical Engineering)

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23 pages, 6473 KiB

Open AccessArticle

Accelerated Simulation of Discrete Event Dynamic Systems via a Multi-Fidelity Modeling Framework

by Seon Han Choi¹, Kyung-Min Seo^2,*

and Tag Gon Kim¹

¹ Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea

² Daewoo Shipbuilding & Marine Engineering (DSME), Seoul 04521, Korea

Appl. Sci. 2017, 7(10), 1056; https://doi.org/10.3390/app7101056 - 13 Oct 2017

Cited by 18 | Viewed by 8068

Abstract

Simulation analysis has been performed for simulation experiments of all possible input combinations as a “what-if” analysis, which causes the simulation to be extremely time-consuming. To resolve this problem, this paper proposes a multi-fidelity modeling framework for enhancing simulation speed while minimizing simulation [...] Read more.

Simulation analysis has been performed for simulation experiments of all possible input combinations as a “what-if” analysis, which causes the simulation to be extremely time-consuming. To resolve this problem, this paper proposes a multi-fidelity modeling framework for enhancing simulation speed while minimizing simulation accuracy loss. A target system for this framework is a discrete event dynamic system. The dynamic property of the system facilitates the development of variable fidelity models for the target system due to its high computational cost; and the discrete event property allows for determining when to change the fidelity within a simulation scenario. For formal representation, the paper defines several key concepts such as an interest region, a fidelity change condition, and a selection model. These concepts are integrated into the framework to allow for the achievement of a condition-based disjunction of high- and low-fidelity simulations within a scenario. The proposed framework is applied to two case studies: unmanned underwater and urban transportation vehicles. The results show that simulation speed increases at least 1.21 times with a 5% accuracy loss. We expect that the proposed framework will resolve a computationally expensive problem in the simulation analysis of discrete event dynamic systems. Full article

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

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17 pages, 2841 KiB

Open AccessArticle

Island Partition of Distribution System with Distributed Generators Considering Protection of Vulnerable Nodes

by Gang Xu¹, Shunyu Wu^1,* and Yuanpeng Tan^2,*

¹ School of Electrical and Electronic Engineering, North China Electric Power University, Beijing 102206, China

² Beijing Key Laboratory of Distribution Transformer Energy-Saving Technology, China Electric Power Research Institute, Beijing 100192, China

Appl. Sci. 2017, 7(10), 1057; https://doi.org/10.3390/app7101057 - 16 Oct 2017

Cited by 20 | Viewed by 4031

Abstract

To improve the reliability of power supply in the case of the fault of distribution system with multiple distributed generators (DGs) and reduce the influence of node voltage fluctuation on the stability of distribution system operation in power restoration, this paper proposes an [...] Read more.

To improve the reliability of power supply in the case of the fault of distribution system with multiple distributed generators (DGs) and reduce the influence of node voltage fluctuation on the stability of distribution system operation in power restoration, this paper proposes an island partition strategy of the distribution system considering the protection of vulnerable nodes. First of all, the electrical coupling coefficient of neighboring nodes is put forward according to distribution system topology and equivalent electrical impedance, and the power-dependence relationship between neighboring nodes is calculated based on the direction and level of the power flow between nodes. Then, the bidirectional transmission of the coupling features of neighboring nodes is realized through the modified PageRank algorithm, thus identifying the vulnerable nodes that have a large influence on the stability of distribution system operation. Next, combining the index of node vulnerability, an island partition model is constructed with the restoration of important loads as the primary goal. In addition, the mutually exclusive firefly algorithm (MEFA) is also proposed to realize the interaction of learning and competition among fireflies, thus enhancing the globally optimal solution search ability of the algorithm proposed. The proposed island partition method is verified with a Pacific Gas and Electric Company (PG and E) 60-node test system. Comparison with other methods demonstrates that the new method is feasible for the distribution system with multiple types of distributed generations and valid to enhance the stability and safety of the grid with a relatively power restoration ratio. Full article

(This article belongs to the Special Issue Distribution Power Systems)

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10 pages, 8241 KiB

Open AccessArticle

A Photometric Stereo Using Re-Projected Images for Active Stereo Vision System

by Keonhwa Jung, Seokjung Kim, Sungbin Im, Taehwan Choi and Minho Chang^*

Department of Mechanical Engineering, Korea University, Seoul 02841, Korea

Appl. Sci. 2017, 7(10), 1058; https://doi.org/10.3390/app7101058 - 13 Oct 2017

Cited by 5 | Viewed by 6087

Abstract

In optical 3D shape measurement, stereo vision with structured light can measure 3D scan data with high accuracy and is used in many applications, but fine surface detail is difficult to obtain. On the other hand, photometric stereo can capture surface details but [...] Read more.

In optical 3D shape measurement, stereo vision with structured light can measure 3D scan data with high accuracy and is used in many applications, but fine surface detail is difficult to obtain. On the other hand, photometric stereo can capture surface details but has disadvantages, in that its 3D data accuracy drops and it requires multiple light sources. When the two measurement methods are combined, more accurate 3D scan data and detailed surface features can be obtained at the same time. In this paper, we present a 3D optical measurement technique that uses re-projection of images to implement photometric stereo without an external light source. 3D scan data is enhanced by combining normal vector from this photometric stereo method, and the result is evaluated with the ground truth. Full article

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10 pages, 6133 KiB

Open AccessArticle

Evaluating the NOx Storage Catalysts (NSC) Aging: A Preliminary Analytical Study with Electronic Microscopy

by Leonarda Bellebuono¹, Cosimo Annese², Lucia Catucci¹

, Giuseppe Colafemmina¹

, Roberto Comparelli^3,*

, Pietro Cotugno⁴, Francesco Fracassi¹, Caterina Fusco²

, Angelo Nacci^1,2

and Lucia D’Accolti^1,2,*

¹ Dipartimento di Chimica, Università di Bari “A. Moro”, Via Orabona 4, 70126 Bari, Italy

² ICCOM-CNR, SS Bari, Via Orabona 4, 70126 Bari, Italy

³ IPCF-CNR, SS Bari, via E. Orabona 4, 70125 Bari, Italy

⁴ CONISMA, SS Bari, via E. Orabona 4, 70125 Bari, Italy

Appl. Sci. 2017, 7(10), 1059; https://doi.org/10.3390/app7101059 - 13 Oct 2017

Viewed by 3798

Abstract

This paper describes an expeditious and reliable method for determining the thermal effects in a static condition of commercial NOx storage catalysts (NSCs) using scanning electron microscopy with an energy dispersive X-ray analytical system (SEM/EDS). It is worth remarking that possible changes in [...] Read more.

This paper describes an expeditious and reliable method for determining the thermal effects in a static condition of commercial NOx storage catalysts (NSCs) using scanning electron microscopy with an energy dispersive X-ray analytical system (SEM/EDS). It is worth remarking that possible changes in the morphology and in the elemental composition of the catalyst may be considered as the most important causes of the lower conversion of NOx. The information attained in this work indicates that Pt nanoparticle sintering is strongly increased by the oxygen exposure, and this can be considered a very useful preliminary investigation for the studies already present in the literature on the efficiency of NSCs. Full article

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

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20 pages, 6903 KiB

Open AccessArticle

Human Emotion Recognition with Electroencephalographic Multidimensional Features by Hybrid Deep Neural Networks

by Youjun Li¹

, Jiajin Huang¹, Haiyan Zhou¹ and Ning Zhong^1,2,3,*

¹ Institute of International WIC, Beijing University of Technology, Beijing 100124, China

² Beijing Advanced Innovation Center for Future Internet Technology, Beijing University of Technology, Beijing 100124, China

³ Knowledge Information Systems Lab, Department of Life Science and Informatics, Maebashi Institute of Technology, Maebashi 371-0816, Japan

Appl. Sci. 2017, 7(10), 1060; https://doi.org/10.3390/app7101060 - 13 Oct 2017

Cited by 163 | Viewed by 13089

Abstract

The aim of this study is to recognize human emotions by electroencephalographic (EEG) signals. The innovation of our research methods involves two aspects: First, we integrate the spatial characteristics, frequency domain, and temporal characteristics of the EEG signals, and map them to a [...] Read more.

The aim of this study is to recognize human emotions by electroencephalographic (EEG) signals. The innovation of our research methods involves two aspects: First, we integrate the spatial characteristics, frequency domain, and temporal characteristics of the EEG signals, and map them to a two-dimensional image. With these images, we build a series of EEG Multidimensional Feature Image (EEG MFI) sequences to represent the emotion variation with EEG signals. Second, we construct a hybrid deep neural network to deal with the EEG MFI sequences to recognize human emotional states where the hybrid deep neural network combined the Convolution Neural Networks (CNN) and Long Short-Term-Memory (LSTM) Recurrent Neural Networks (RNN). Empirical research is carried out with the open-source dataset DEAP (a Dataset for Emotion Analysis using EEG, Physiological, and video signals) using our method, and the results demonstrate the significant improvements over current state-of-the-art approaches in this ﬁeld. The average emotion classification accuracy of each subject with CLRNN (the hybrid neural networks that we proposed in this study) is 75.21%. Full article

(This article belongs to the Special Issue Smart Healthcare)

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25 pages, 5044 KiB

Open AccessArticle

Albatross-Like Utilization of Wind Gradient for Unpowered Flight of Fixed-Wing Aircraft

by Shangqiu Shan^*

, Zhongxi Hou and Bingjie Zhu

College of Aerospace Sciences and Engineering, National University of Defense Technology, Changsha 410073, China

Appl. Sci. 2017, 7(10), 1061; https://doi.org/10.3390/app7101061 - 14 Oct 2017

Cited by 3 | Viewed by 7246

Abstract

The endurance of an aircraft can be considerably extended by its exploitation of the hidden energy of a wind gradient, as an albatross does. The process is referred to as dynamic soaring and there are two methods for its implementation, namely, sustainable climbing [...] Read more.

The endurance of an aircraft can be considerably extended by its exploitation of the hidden energy of a wind gradient, as an albatross does. The process is referred to as dynamic soaring and there are two methods for its implementation, namely, sustainable climbing and the Rayleigh cycle. In this study, the criterion for sustainable climbing was determined, and a bio-inspired method for implementing the Rayleigh cycle in a shear wind was developed. The determined sustainable climbing criterion promises to facilitate the development of an unpowered aircraft and the choice of a more appropriate soaring environment, as was demonstrated in this study. The criterion consists of three factors, namely, the environment, aerodynamics, and wing loading. We develop an intuitive explanation of the Raleigh cycle and analyze the energy mechanics of utilizing a wind gradient in unpowered flight. The energy harvest boundary and extreme power point were determined and used to design a simple bio-inspired guidance strategy for implementing the Rayleigh cycle. The proposed strategy, which involves the tuning of a single parameter, can be easily implemented in real-time applications. In the results and discussions, the effects of each factor on climbing performance are examined and the sensitivity of the aircraft factor is discussed using five examples. Experimental MATLAB simulations of the proposed strategy and the comparison of the results with those of Gauss Pseudospectral Optimization Software confirm the feasibility of the proposed strategy. Full article

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19 pages, 15201 KiB

Open AccessArticle

Sound Radiation of Aerodynamically Excited Flat Plates into Cavities

by Johannes Osterziel^1,*

, Florian J. Zenger²

and Stefan Becker²

¹ Department of Electrical, Electronic and Communication Engineering, Chair of Sensor Technology, Friedrich-Alexander University Erlangen-Nürnberg, Paul-Gordan-Straße 3/5, Erlangen 91052, Germany

² Department of Chemical and Biological Engineering, Institute of Process Machinery and Systems Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Cauerstraße 4, Erlangen 91058, Germany

Appl. Sci. 2017, 7(10), 1062; https://doi.org/10.3390/app7101062 - 14 Oct 2017

Cited by 9 | Viewed by 6630

Abstract

Flow-induced vibrations and the sound radiation of flexible plate structures of different thickness mounted in a rigid plate are experimentally investigated. Therefore, flow properties and turbulent boundary layer parameters are determined through measurements with a hot-wire anemometer in an aeroacoustic wind tunnel. Furthermore, [...] Read more.

Flow-induced vibrations and the sound radiation of flexible plate structures of different thickness mounted in a rigid plate are experimentally investigated. Therefore, flow properties and turbulent boundary layer parameters are determined through measurements with a hot-wire anemometer in an aeroacoustic wind tunnel. Furthermore, the excitation of the vibrating plate is examined by laser scanning vibrometry. To describe the sound radiation and the sound transmission of the flexible aluminium plates into cavities, a cuboid-shaped room with adjustable volume and 34 flush-mounted microphones is installed at the non flow-excited side of the aluminium plates. Results showed that the sound field inside the cavity is on the one hand dependent on the flow parameters and the plate thickness and on the other hand on the cavity volume which indirectly influences the level and the distribution of the sound pressure behind the flexible plate through different excited modes. Full article

(This article belongs to the Special Issue Advances in Vibroacoustics and Aeroacustics of Aerospace and Automotive Systems)

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20 pages, 8516 KiB

Open AccessArticle

Numerical Study on Guided Wave Propagation in Wood Utility Poles: Finite Element Modelling and Parametric Sensitivity Analysis

by Yang Yu^*

and Ning Yan

School of Civil and Environmental Engineering, University of Technology Sydney, Sydney NSW 2007, Australia

Appl. Sci. 2017, 7(10), 1063; https://doi.org/10.3390/app7101063 - 14 Oct 2017

Cited by 18 | Viewed by 5951

Abstract

Recently, guided wave (GW)-based non-destructive evaluation (NDE) techniques have been developed and considered as a potential candidate for integrity assessment of wood structures, such as wood utility poles. However, due to the lack of understanding on wave propagation in such structures, especially under [...] Read more.

Recently, guided wave (GW)-based non-destructive evaluation (NDE) techniques have been developed and considered as a potential candidate for integrity assessment of wood structures, such as wood utility poles. However, due to the lack of understanding on wave propagation in such structures, especially under the effect of surroundings such as soil, current GW-based NDE methods fail to properly account for the propagation of GWs and to contribute reliable and correct results. To solve this critical issue, this work investigates the behaviour of wave propagation in the wood utility pole with the consideration of the influence of soil. The commercial finite element (FE) analysis software ANSYS is used to simulate GW propagation in a wood utility pole. In order to verify the numerical findings, the laboratory testing is also conducted in parallel with the numerical results to experimentally verify the effectiveness of developed FE models. Finally, sensitivity analysis is also carried out based on FE models of wood pole under different material properties, boundary conditions and excitation types. Full article

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12 pages, 2167 KiB

Open AccessArticle

Mathematical Modelling and Optimization of Cutting Force, Tool Wear and Surface Roughness by Using Artificial Neural Network and Response Surface Methodology in Milling of Ti-6242S

by Erol Kilickap¹, Ahmet Yardimeden^1,*

and Yahya Hışman Çelik²

¹ Department of Mechanical Engineering, Faculty of Engineering, Dicle University, Diyarbakir 21280, Turkey

² Department of Mechanical Engineering, Faculty of Engineering-Architecture, Batman University, Batman 72060, Turkey

Appl. Sci. 2017, 7(10), 1064; https://doi.org/10.3390/app7101064 - 15 Oct 2017

Cited by 103 | Viewed by 8166

Abstract

In this paper, an experimental study was conducted to determine the effect of different cutting parameters such as cutting speed, feed rate, and depth of cut on cutting force, surface roughness, and tool wear in the milling of Ti-6242S alloy using the cemented [...] Read more.

In this paper, an experimental study was conducted to determine the effect of different cutting parameters such as cutting speed, feed rate, and depth of cut on cutting force, surface roughness, and tool wear in the milling of Ti-6242S alloy using the cemented carbide (WC) end mills with a 10 mm diameter. Data obtained from experiments were defined both Artificial Neural Network (ANN) and Response Surface Methodology (RSM). ANN trained network using Levenberg-Marquardt (LM) and weights were trained. On the other hand, the mathematical models in RSM were created applying Box Behnken design. Values obtained from the ANN and the RSM was found to be very close to the data obtained from experimental studies. The lowest cutting force and surface roughness were obtained at high cutting speeds and low feed rate and depth of cut. The minimum tool wear was obtained at low cutting speed, feed rate, and depth of cut. Full article

(This article belongs to the Section Mechanical Engineering)

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15 pages, 7063 KiB

Open AccessArticle

Effect of Molybdenum on the Microstructures and Properties of Stainless Steel Coatings by Laser Cladding

by Kaiming Wang¹, Baohua Chang^1,*

, Jiongshen Chen², Hanguang Fu^2,*, Yinghua Lin³ and Yongping Lei²

¹ State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Haidian District, Beijing 100084, China

² School of Materials Science and Engineering, Beijing University of Technology, Number 100, Pingle Garden, Chaoyang District, Beijing 100124, China

³ Institute of Laser Advanced Manufacturing, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China

Appl. Sci. 2017, 7(10), 1065; https://doi.org/10.3390/app7101065 - 15 Oct 2017

Cited by 74 | Viewed by 7499

Abstract

Stainless steel powders with different molybdenum (Mo) contents were deposited on the substrate surface of 45 steel using a 6 kW fiber laser. The microstructure, phase, microhardness, wear properties, and corrosion resistance of coatings with different Mo contents were studied by scanning electron [...] Read more.

Stainless steel powders with different molybdenum (Mo) contents were deposited on the substrate surface of 45 steel using a 6 kW fiber laser. The microstructure, phase, microhardness, wear properties, and corrosion resistance of coatings with different Mo contents were studied by scanning electron microscopy (SEM), electron probe microanalyzer (EPMA), X-ray diffraction (XRD), microhardness tester, wear tester, and electrochemical techniques. The results show that good metallurgical bonding was achieved between the stainless steel coating and the substrate. The amount of M₇(C, B)₃ type borocarbide decreases and that of M₂B and M₂₃(C, B)₆ type borocarbides increases with the increase of Mo content in the coatings. The amount of martensite decreases, while the amount of ferrite gradually increases with the increase of Mo content. When the Mo content is 4.0 wt. %, Mo₂C phase appears in the coating. The microstructure of the coating containing Mo is finer than that of the Mo-free coating. The microhardness decreases and the wear resistance of the coating gradually improves with the increase of Mo content. The wear resistance of the 6.0 wt. % Mo coating is about 3.7 times that of the Mo-free coating. With the increase of Mo content, the corrosion resistance of the coating firstly increases and then decreases. When the Mo content is 2.0 wt. %, the coating has the best corrosion resistance. Full article

(This article belongs to the Special Issue Solid State Lasers Materials, Technologies and Applications)

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18 pages, 4422 KiB

Open AccessArticle

Automatic Matching of Multi-Source Satellite Images: A Case Study on ZY-1-02C and ETM+

by Bo Wang^1,*, Jiefei Peng¹, Xiaojie Wu² and Jianwei Bao¹

¹ College of Astronautics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China

² Tianjin Key Laboratory of Intelligent Information Processing in Remote Sensing, Tianjin 300000, China

Appl. Sci. 2017, 7(10), 1066; https://doi.org/10.3390/app7101066 - 15 Oct 2017

Cited by 4 | Viewed by 3402

Abstract

The ever-growing number of applications for satellites is being compromised by their poor direct positioning precision. Existing orthoimages, such as enhanced thematic mapper (ETM+) orthoimages, can provide georeferences or improve the geo-referencing accuracy of satellite images, such ZY-1-02C images that have unsatisfactory positioning [...] Read more.

The ever-growing number of applications for satellites is being compromised by their poor direct positioning precision. Existing orthoimages, such as enhanced thematic mapper (ETM+) orthoimages, can provide georeferences or improve the geo-referencing accuracy of satellite images, such ZY-1-02C images that have unsatisfactory positioning precision, thus enhancing their processing efficiency and application. In this paper, a feasible image matching approach using multi-source satellite images is proposed on the basis of an experiment carried out with ZY-1-02C Level 1 images and ETM+ orthoimages. The proposed approach overcame differences in rotation angle, scale, and translation between images. The rotation and scale variances were evaluated on the basis of rational polynomial coefficients. The translation vectors were generated after blocking the overall phase correlation. Then, normalized cross-correlation and least-squares matching were applied for matching. Finally, the gross errors of the corresponding points were eliminated by local statistic vectors in a TIN structure. Experimental results showed a matching precision of less than two pixels (root-mean-square error), and comparison results indicated that the proposed method outperforms Scale-Invariant Feature Transform (SIFT), Speeded Up Robust Features (SURF), and Affine-Scale Invariant Feature Transform (A-SIFT) in terms of reliability and efficiency. Full article

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14 pages, 2419 KiB

Open AccessArticle

Estimating Co-Contraction Activation of Trunk Muscles Using a Novel Musculoskeletal Model for Pregnant Women

by Saori Morino^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, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan

Appl. Sci. 2017, 7(10), 1067; https://doi.org/10.3390/app7101067 - 15 Oct 2017

Cited by 6 | Viewed by 11750

Abstract

Weight gain and stretched abdominal muscles from an enlarged gravid uterus are remarkable features during pregnancy. These changes elicit postural instability and place strain on body segments, contributing to lower back pain. In general, the agonist and antagonist muscles act simultaneously to increase [...] Read more.

Weight gain and stretched abdominal muscles from an enlarged gravid uterus are remarkable features during pregnancy. These changes elicit postural instability and place strain on body segments, contributing to lower back pain. In general, the agonist and antagonist muscles act simultaneously to increase joint stabilization; however, this can cause additional muscle stress during movement. Furthermore, this activation can be observed in pregnant women because of their unstable body joints. Hence, physical modalities based on assessments of muscle activation are useful for managing low back pain during pregnancy. Musculoskeletal models are common when investigating muscle load. However, it is difficult to apply such models to pregnant women and estimate the co-contraction of muscles using musculoskeletal models. Therefore, the purpose of this study is to construct a musculoskeletal model for pregnant women that estimates the co-contraction of trunk muscles. First, motion analysis was conducted on a pregnant woman and the muscle activations of the rectus abdominis and erector spinae were measured. Then, the musculoskeletal model was specifically modified for pregnant women. Finally, the co-contraction was estimated from the results of the musculoskeletal model and electromyography data using a genetic algorithm. With the proposed methods, weakened abdominal muscle torque and the co-contraction activation of trunk muscles were estimated successfully. Full article

(This article belongs to the Section Mechanical Engineering)

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22 pages, 4978 KiB

Open AccessArticle

Model Based Open-Loop Wind Farm Control Using Active Power for Power Increase and Load Reduction

by Hyungyu Kim, Kwansu Kim and Insu Paek^*

Department of Advanced Mechanical Engineering, Kangwon National University, Chuncheon-si 24341, Gangwon-do, Korea

Appl. Sci. 2017, 7(10), 1068; https://doi.org/10.3390/app7101068 - 16 Oct 2017

Cited by 22 | Viewed by 5855

Abstract

A new wind farm control algorithm that adjusts the power output of the most upstream wind turbine in a wind farm for power increase and load reduction was developed in this study. The algorithm finds power commands to individual wind turbines to maximize [...] Read more.

A new wind farm control algorithm that adjusts the power output of the most upstream wind turbine in a wind farm for power increase and load reduction was developed in this study. The algorithm finds power commands to individual wind turbines to maximize the total power output from the wind farm when the power command from the transmission system operator is larger than the total available power from the wind farm. To validate this wind farm control algorithm, a relatively high fidelity wind farm simulation tool developed in the previous study was modified to include a wind farm controller which consists of a wind speed estimator, a power command calculator and a simplified wind farm model. In addition, the wind turbine controller in the simulation tool was modified to include a demanded power tracking algorithm. For a virtual wind farm with three 5 MW wind turbines aligned with the wind, simulations were performed with various ambient turbulent intensities, turbine spacing, and control frequencies. It was found from the dynamic simulation using turbulent winds that the proposed wind farm control algorithm can increase the power output and decrease the tower load of the most upstream wind turbine compared with the results with the conventional wind farm control. Full article

(This article belongs to the Special Issue Active Flow Control Technologies for Energy and Propulsive Systems)

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22 pages, 2908 KiB

Open AccessArticle

Secure Authentication and Prescription Safety Protocol for Telecare Health Services Using Ubiquitous IoT

by Zahid Mahmood¹, Huansheng Ning^1,*

, Ata Ullah²

and Xuanxia Yao¹

¹ School of Computer and Communication Engineering University of Science and Technology Beijing (USTB), Beijing 10008, China

² Department of Computer Science, National University of Modern Languages, Islamabad 44000, Pakistan

Appl. Sci. 2017, 7(10), 1069; https://doi.org/10.3390/app7101069 - 16 Oct 2017

Cited by 36 | Viewed by 6284

Abstract

Internet-of-Things (IoT) include a large number of devices that can communicate across different networks. Cyber-Physical Systems (CPS) also includes a number of devices connected to the internet where wearable devices are also included. Both systems enable researchers to develop healthcare systems with additional [...] Read more.

Internet-of-Things (IoT) include a large number of devices that can communicate across different networks. Cyber-Physical Systems (CPS) also includes a number of devices connected to the internet where wearable devices are also included. Both systems enable researchers to develop healthcare systems with additional intelligence as well as prediction capabilities both for lifestyle and in hospitals. It offers as much persistence as a platform to ubiquitous healthcare by using wearable sensors to transfer the information over servers, smartphones, and other smart devices in the Telecare Medical Information System (TMIS). Security is a challenging issue in TMIS, and resourceful access to health care services requires user verification and confidentiality. Existing schemes lack in ensuring reliable prescription safety along with authentication. This research presents a Secure Authentication and Prescription Safety (SAPS) protocol to ensure secure communication between the patient, doctor/nurse, and the trusted server. The proposed procedure relies upon the efficient elliptic curve cryptosystem which can generate a symmetric secure key to ensure secure data exchange between patients and physicians after successful authentication of participants individually. A trusted server is involved for mutual authentication between parties and then generates a common key after completing the validation process. Moreover, the scheme is verified by doing formal modeling using Rubin Logic and validated using simulations in NS-2.35. We have analyzed the SAPS against security attacks, and then performance analysis is elucidated. Results prove the dominance of SAPS over preliminaries regarding mutual authentication, message integrity, freshness, and session key management and attack prevention. Full article

(This article belongs to the Special Issue Smart Healthcare)

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11 pages, 8660 KiB

Open AccessArticle

Numerical Simulation of an Oscillatory-Type Tidal Current Powered Generator Based on Robotic Fish Technology

by Ikuo Yamamoto^1,*, Guiming Rong², Yoichi Shimomoto² and Murray Lawn³

¹ Organization for Marine Science and Technology, Nagasaki University, Nagasaki 852-8521, Japan

² Graduate School of Engineering, Nagasaki University, Nagasaki 852-8521, Japan

³ Surgical Oncology, School of Medicine, Nagasaki University, Nagasaki 852-8521, Japan

Appl. Sci. 2017, 7(10), 1070; https://doi.org/10.3390/app7101070 - 16 Oct 2017

Cited by 4 | Viewed by 6428

Abstract

The generation of clean renewable energy is becoming increasingly critical, as pollution and global warming threaten the environment in which we live. While there are many different kinds of natural energy that can be harnessed, marine tidal energy offers reliability and predictability. However, [...] Read more.

The generation of clean renewable energy is becoming increasingly critical, as pollution and global warming threaten the environment in which we live. While there are many different kinds of natural energy that can be harnessed, marine tidal energy offers reliability and predictability. However, harnessing energy from tidal flows is inherently difficult, due to the harsh environment. Current mechanisms used to harness tidal flows center around propeller-based solutions but are particularly prone to failure due to marine fouling from such as encrustations and seaweed entanglement and the corrosion that naturally occurs in sea water. In order to efficiently harness tidal flow energy in a cost-efficient manner, development of a mechanism that is inherently resistant to these harsh conditions is required. One such mechanism is a simple oscillatory-type mechanism based on robotic fish tail fin technology. This uses the physical phenomenon of vortex-induced oscillation, in which water currents flowing around an object induce transverse motion. We consider two specific types of oscillators, firstly a wing-type oscillator, in which the optimal elastic modulus is being sort. Secondly, the optimal selection of shape from 6 basic shapes for a reciprocating oscillating head-type oscillator. A numerical analysis tool for fluid structure-coupled problems—ANSYS—was used to select the optimum softness of material for the first type of oscillator and the best shape for the second type of oscillator, based on the exhibition of high lift coefficients. For a wing-type oscillator, an optimum elastic modulus for an air-foil was found. For a self-induced vibration-type mechanism, based on analysis of vorticity and velocity distribution, a square-shaped head exhibited a lift coefficient of more than two times that of a cylindrically shaped head. Analysis of the flow field clearly showed that the discontinuous flow caused by a square-headed oscillator results in higher lift coefficients due to intense vortex shedding, and that stable operation can be achieved by selecting the optimum length to width ratio. Full article

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

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21 pages, 10880 KiB

Open AccessArticle

Compact Left-Handed Meta-Atom for S-, C- and Ku-Band Application

by Md. Mehedi Hasan^1,*

, Mohammad Rashed Iqbal Faruque^1,*

and Mohammad Tariqul Islam^2,*

¹ Space Science Centre (ANGKASA), Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

² Department of Electrical, Electronic and Systems Engineering, Universiti Kebangsan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

Appl. Sci. 2017, 7(10), 1071; https://doi.org/10.3390/app7101071 - 23 Oct 2017

Cited by 38 | Viewed by 6519 | Correction

Abstract

A new compact left-handed meta-atom for S-, C- and Ku-band applications is presented in this paper. The proposed structure provides a wide bandwidth and exhibits left-handed characteristics at 0°, 90°, 180° and 270° (xy-axes) rotations. Besides, the left-handed characteristics and wide bandwidth of [...] Read more.

A new compact left-handed meta-atom for S-, C- and Ku-band applications is presented in this paper. The proposed structure provides a wide bandwidth and exhibits left-handed characteristics at 0°, 90°, 180° and 270° (xy-axes) rotations. Besides, the left-handed characteristics and wide bandwidth of 1 × 2, 2 × 2, 3 × 3 and 4 × 4 arrays are also investigated at the above-mentioned rotation angles. In this study, the meta-atom is designed by creating splits at the outer and inner square-shaped ring resonators, and a metal arm is placed at the middle of the inner ring resonator. The arm is also connected to the upper and lower portions of the inner ring resonator, and later, the design appears as an I-shaped split ring resonator. The commercially available, finite integration technique (FIT)-based electromagnetic simulator CST Microwave Studio is used for design and simulation purposes. The measured data comply well with the simulated data of the unit cell for 1 × 2, 2 × 2, 3 × 3 and 4 × 4 arrays at every rotation angle. Owing to the effective medium ratio (EMR) of 8.50 at 0° and 180° rotations, the proposed meta-atom structure is compact in size. Moreover, due to the quality factor of 82, the designed meta-atom is flexible for high-performance antenna, filter and sensor applications. Therefore, the meta-atom integrated antenna shows multi frequency bands with the highest peak gain of 5 dBi, which is used as the long distance radio communication frequency. Full article

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25 pages, 1904 KiB

Open AccessArticle

Future of IoT Networks: A Survey

by Suk Kyu Lee¹, Mungyu Bae² and Hwangnam Kim^2,*

¹ LG Electronics Inc., Seoul 06772, Korea

² School of Electrical Engineering, Korea University, Seoul 02841, Korea

Appl. Sci. 2017, 7(10), 1072; https://doi.org/10.3390/app7101072 - 16 Oct 2017

Cited by 179 | Viewed by 19819

Abstract

The introduction of mobile devices has changed our daily lives. They enable users to obtain information even in a nomadic environment and provide information without limitations. A decade after the introduction of this technology, we are now facing the next innovation that will [...] Read more.

The introduction of mobile devices has changed our daily lives. They enable users to obtain information even in a nomadic environment and provide information without limitations. A decade after the introduction of this technology, we are now facing the next innovation that will change our daily lives. With the introduction of the Internet of Things (IoT), our communication ability will not be restricted to only mobile devices. Rather, it will expand to all things with which we coexist. Many studies have discussed IoT-related services and platforms. However, there are only limited discussions about the IoT network. In this paper, we will thoroughly analyze the technical details about the IoT network. Based on our survey of papers, we will provide insight about the future IoT network and the crucial components that will enable it. Full article

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25 pages, 1370 KiB

Open AccessArticle

Heuristic Method for Decision-Making in Common Scheduling Problems

by Edyta Kucharska

Department of Automatics and Biomedical Engineering, AGH University of Science and Technology, 30 Mickiewicza Av, 30-059 Krakow, Poland

Appl. Sci. 2017, 7(10), 1073; https://doi.org/10.3390/app7101073 - 17 Oct 2017

Cited by 6 | Viewed by 4448

Abstract

The aim of the paper is to present a heuristic method for decision-making regarding an NP-hard scheduling problem with limitations related to tasks and the resources dependent on the current state of the process. The presented approach is based on the algebraic-logical meta-model [...] Read more.

The aim of the paper is to present a heuristic method for decision-making regarding an NP-hard scheduling problem with limitations related to tasks and the resources dependent on the current state of the process. The presented approach is based on the algebraic-logical meta-model (ALMM), which enables making collective decisions in successive process stages, not separately for individual objects or executors. Moreover, taking into account the limitations of the problem, it involves constructing only an acceptable solution and significantly reduces the amount of calculations. A general algorithm based on the presented method is composed of the following elements: preliminary analysis of the problem, techniques for the choice of decision at a given state, the pruning non-perspective trajectory, selection technique of the initial state for the trajectory final part, and the trajectory generation parameters modification. The paper includes applications of the presented approach to scheduling problems on unrelated parallel machines with a deadline and machine setup time dependent on the process state, where the relationship between tasks is defined by the graph. The article also presents the results of computational experiments. Full article

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

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23 pages, 10793 KiB

Open AccessArticle

Downdraft Assessment of Glass Curtain Wall Buildings with a Radiant Floor Heating System

by Goosang Joe¹, Dongwoo Kim¹, Sanghoon Park², Sojeong Park³, Myoungsouk Yeo^1,* and Kwangwoo Kim¹

¹ Department of Architecture and Architectural Engineering, Seoul National University, Seoul 08826, Korea

² LG Hausys R&D Center, Seoul 08826, Korea

³ Department of Architecture, Jung-Gu Office, Seoul 08826, Korea

Appl. Sci. 2017, 7(10), 1075; https://doi.org/10.3390/app7101075 - 17 Oct 2017

Cited by 4 | Viewed by 6155

Abstract

The present study aims to evaluate whether downdraft can be prevented by applying a radiant floor heating system in glass curtain wall buildings. A radiant floor heating system does not directly supply heat to cold air, but does so via heat exchange with [...] Read more.

The present study aims to evaluate whether downdraft can be prevented by applying a radiant floor heating system in glass curtain wall buildings. A radiant floor heating system does not directly supply heat to cold air, but does so via heat exchange with a cold airflow. Assessing whether a downdraft is prevented is, thus, necessary. For this assessment, a radiant floor heating system was applied to perimeter zones with different window types modeled using a computational fluid dynamics (CFD) simulation. The relationship between the radiant floor heating system and the windows was examined via an assessment of the resulting downdraft by considering the radiant heat exchange effect between the window and the floor. The assessment was conducted by utilizing a CFD simulation. The simulation results show that the temperature difference between the air supplied through the radiant floor heating system and the air descending along the cold surface of the window increased when the radiant floor heating system was applied to a narrow area with a high temperature. Furthermore, the airflow velocity increased with the heat exchange. The airflow re-entered the window side, and the downdraft in the occupied area exceeded the strict value specified by the standards. Conversely, if heat were applied according to the indoor thermal output by widening the radiant heat area of the radiant floor heating system, a downdraft could occur as a result of a blocking failure prior to the influx of the cold air into the occupied area caused by low surface temperatures. Therefore, applying a radiant floor heating system is advantageous in a perimeter zone without causing airflow inducement at the window side with acceptable surface temperatures. Full article

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15 pages, 7316 KiB

Open AccessArticle

Influence of the Microwave Heating Time on the Self-Healing Properties of Asphalt Mixtures

by Jose Norambuena-Contreras

and Irene Gonzalez-Torre^*

LabMAT, Department of Civil and Environmental Engineering, University of Bío-Bío, Concepción 4051381, Chile

Appl. Sci. 2017, 7(10), 1076; https://doi.org/10.3390/app7101076 - 18 Oct 2017

Cited by 69 | Viewed by 7975

Abstract

This paper aims to evaluate the influence of the microwave heating time on the self-healing properties of fibre-reinforced asphalt mixtures. To this purpose, self-healing properties of dense asphalt mixtures with four different percentages of steel wool fibres were evaluated as the three-point bending [...] Read more.

This paper aims to evaluate the influence of the microwave heating time on the self-healing properties of fibre-reinforced asphalt mixtures. To this purpose, self-healing properties of dense asphalt mixtures with four different percentages of steel wool fibres were evaluated as the three-point bending strength before and after healing via microwave heating at four different heating times. Furthermore, the thermal behaviour of asphalt mixtures during microwave heating was also evaluated. With the aim of quantifying the efficiency of the repair process, ten damage-healing cycles were done in the test samples. In addition, self-healing results were compared with the fibre spatial distribution inside asphalt samples evaluated by CT-scans. Crack-size change on asphalt samples during healing cycles was also evaluated through optical microscopy. It was found that the heating time is the most influential variable on the healing level reached by the asphalt mixtures tested by microwave radiation. CT-Scans results proved that fibre spatial distribution into the asphalt mixtures play an important role in the asphalt healing level. Finally, it was concluded that 40 s was the optimum heating time to reach the highest healing levels with the lowest damage on the asphalt samples, and that heating times over 30 s can seal the cracks, thus achieving the self-healing of asphalt mixtures via microwave heating. Full article

(This article belongs to the Special Issue Self-Healing Asphalt)

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18 pages, 2847 KiB

Open AccessArticle

A Prototype Design and Development of the Smart Photovoltaic System Blind Considering the Photovoltaic Panel, Tracking System, and Monitoring System

by Kwangbok Jeong¹, Taehoon Hong^1,*

, Choongwan Koo², Jeongyoon Oh¹, Minhyun Lee¹ and Jimin Kim^1,3

¹ Department of Architecture & Architectural Engineering, Yonsei University, Seoul 03722, Korea

² Department of Building Services Engineering, Hong Kong Polytechnic University, Kowloon, Hong Kong, China

³ Division of Construction Engineering and Management, Purdue University, West Lafayette, IN 47907, USA

Appl. Sci. 2017, 7(10), 1077; https://doi.org/10.3390/app7101077 - 18 Oct 2017

Cited by 21 | Viewed by 8668

Abstract

This study aims to design and develop the prototype models of the smart photovoltaic system blind (SPSB). To achieve this objective, the study defined the properties in three ways: (i) the photovoltaic (PV) panel; (ii) the tracking system; and (iii) the monitoring system. [...] Read more.

This study aims to design and develop the prototype models of the smart photovoltaic system blind (SPSB). To achieve this objective, the study defined the properties in three ways: (i) the photovoltaic (PV) panel; (ii) the tracking system; and (iii) the monitoring system. First, the amorphous silicon PV panel was determined as a PV panel, and the width and length of the PV panel were determined to be 50 mm and 250 mm, respectively. Second, the four tracker types (i.e., fixed type, vertical single-axis tracker, horizontal single-axis tracker, and azimuth-altitude dual-axis tracker) was applied, as well as the direct tracking method based on the amount of electricity generated as a tracking system. Third, the electricity generation and environmental conditions were chosen as factors to be monitored in order to evaluate and manage the technical performance of SPSB as a monitoring system. The prototype model of the SPSB is designed and developed for providing the electricity generated from its PV panel, as well as for reducing the indoor cooling demands through the blind’s function, itself (i.e., blocking out sunlight). Full article

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

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9 pages, 1069 KiB

Open AccessArticle

New Class of Wide Energy Gap Benzotriimidazole Optical Materials

by Jianmin Shi¹, J. Matthew Chudomel² and Richard Fu^1,*

¹ U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, MD 20783-1138, USA

² Nalco Ecolab, 1601 West Diehl, Naperville, IL 60563-1198, USA

Appl. Sci. 2017, 7(10), 1078; https://doi.org/10.3390/app7101078 - 18 Oct 2017

Viewed by 4525

Abstract

A new class of wide energy gap benzotriimidazole materials have been synthesized by a two-step condensation reaction. All of the benzotriimidazole compounds have π-π* absorption bands in the range of 250–400 nm. The photoluminescence (PL) quantum efficiency of each benzotriimidazole depends strongly on [...] Read more.

A new class of wide energy gap benzotriimidazole materials have been synthesized by a two-step condensation reaction. All of the benzotriimidazole compounds have π-π* absorption bands in the range of 250–400 nm. The photoluminescence (PL) quantum efficiency of each benzotriimidazole depends strongly on the presence of electron withdrawing groups. PL quantum efficiencies of benzotriimidazoles without electron withdrawing groups were less than desirable (40–43%), while molecules with electron withdrawing groups displayed much stronger PL with efficiencies in the range of 73–75%. The electron withdrawing groups shift the emission to a longer wavelength, towards a more “true blue” color. This new class of benzotriimidazole optical materials could be used as electron-injecting and electron-transporting blue luminescence materials for potential organic light-emitting diode (OLED) applications. Full article

(This article belongs to the Special Issue Fluorescence and Phosphorescence in Organic Materials: from Fundamental to OLED Devices)

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18 pages, 467 KiB

Open AccessArticle

Portfolio Implementation Risk Management Using Evolutionary Multiobjective Optimization

by David Quintana^1,*,†

, Roman Denysiuk², Sandra Garcia-Rodriguez³ and António Gaspar-Cunha²

¹ Department of Computer Science, Universidad Carlos III de Madrid, Madrid 28911, Spain

² IPC—Institute of Polymers and Composites, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal

³ CEA, LIST, Data Analysis and System Intelligence Laboratory, 91191 Gif-sur-Yvette, France

^† Current address: Department of Computer Science, Universidad Carlos III de Madrid, Av. de la Universidad 30, Leganés, 28911 Madrid, Spain.

Appl. Sci. 2017, 7(10), 1079; https://doi.org/10.3390/app7101079 - 18 Oct 2017

Cited by 12 | Viewed by 4489

Abstract

Portfolio management based on mean-variance portfolio optimization is subject to different sources of uncertainty. In addition to those related to the quality of parameter estimates used in the optimization process, investors face a portfolio implementation risk. The potential temporary discrepancy between target and [...] Read more.

Portfolio management based on mean-variance portfolio optimization is subject to different sources of uncertainty. In addition to those related to the quality of parameter estimates used in the optimization process, investors face a portfolio implementation risk. The potential temporary discrepancy between target and present portfolios, caused by trading strategies, may expose investors to undesired risks. This study proposes an evolutionary multiobjective optimization algorithm aiming at regions with solutions more tolerant to these deviations and, therefore, more reliable. The proposed approach incorporates a user’s preference and seeks a fine-grained approximation of the most relevant efficient region. The computational experiments performed in this study are based on a cardinality-constrained problem with investment limits for eight broad-category indexes and 15 years of data. The obtained results show the ability of the proposed approach to address the robustness issue and to support decision making by providing a preferred part of the efficient set. The results reveal that the obtained solutions also exhibit a higher tolerance to prediction errors in asset returns and variance–covariance matrix. Full article

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16 pages, 7583 KiB

Open AccessArticle

Application of a Coupled Eulerian-Lagrangian Technique on Constructability Problems of Site on Very Soft Soil

by Junyoung Ko¹, Sangseom Jeong² and Junghwan Kim^2,*

¹ Department of Civil, Environmental, and Construction Engineering, Texas Tech University, Lubbock, TX 79409, USA

² Department of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Korea

Appl. Sci. 2017, 7(10), 1080; https://doi.org/10.3390/app7101080 - 18 Oct 2017

Cited by 16 | Viewed by 6020

Abstract

This paper presents the application of the Coupled Eulerian–Lagrangian (CEL) technique on the constructability problems of site on very soft soil. The main objective of this study was to investigate the constructability and application of two ground improvement methods, such as the forced [...] Read more.

This paper presents the application of the Coupled Eulerian–Lagrangian (CEL) technique on the constructability problems of site on very soft soil. The main objective of this study was to investigate the constructability and application of two ground improvement methods, such as the forced replacement method and the deep mixing method. The comparison between the results of CEL analyses and field investigations was performed to verify the CEL modelling. The behavior of very soft soil and constructability with methods can be appropriately investigated using the CEL technique, which would be useful tools for comprehensive reviews in preliminary design. Full article

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22 pages, 9959 KiB

Open AccessArticle

Mechanisms of Sweep on the Performance of Transonic Centrifugal Compressor Impellers

by Xiao He and Xinqian Zheng^*

Turbomachinery Laboratory, State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China

Appl. Sci. 2017, 7(10), 1081; https://doi.org/10.3390/app7101081 - 18 Oct 2017

Cited by 18 | Viewed by 10589

Abstract

Transonic centrifugal compressors with high performance are required in the oil and gas industries, modern gas turbine engines, and turbochargers. The sweep of the blades is one of the crucial features that have a significant influence on their performance. This paper numerically investigates [...] Read more.

Transonic centrifugal compressors with high performance are required in the oil and gas industries, modern gas turbine engines, and turbochargers. The sweep of the blades is one of the crucial features that have a significant influence on their performance. This paper numerically investigates mechanisms by which sweep affects the performance of a transonic impeller with twin splitters. Sweep is defined as scaling up or down the shroud chord, and the variation range of the sweep angle has been chosen from −25 to +25°. In the current case, results show that the variation of choke mass flow rate, pressure ratio, and efficiency value is around 1%. If the centrifugal compressor has a higher pressure ratio or a higher front loading, the sweep effect on compressor performance will be even stronger. The essential aerodynamic effect of sweep is the spanwise redistribution of the front loading, resulting in effects on the shock structure, the tip leakage vortex, and the flow separation. On the shroud section, forward sweep restricts the front loading, the shock strength, and the tip leakage vortex, which reduces the loss near the casing. On the hub section, aft sweep suppresses the front loading and the flow separation, which reduces the loss near the hub. It is the delicate balance between controlling the loss near the hub and the loss near the casing that determines the optimal sweep angle design. Full article

(This article belongs to the Section Mechanical Engineering)

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29 pages, 2481 KiB

Open AccessArticle

Cybersecurity and Network Forensics: Analysis of Malicious Traffic towards a Honeynet with Deep Packet Inspection

by Gabriel Arquelau Pimenta Rodrigues^1,†

, Robson De Oliveira Albuquerque^1,†

, Flávio Elias Gomes de Deus^1,†, Rafael Timóteo De Sousa Jr.^1,†

, Gildásio Antônio De Oliveira Júnior^1,†, Luis Javier García Villalba^2,*,†

and Tai-Hoon Kim^3,†

¹ Cybersecurity INCT Unit 6, Decision Technologies Laboratory-LATITUDE, Electrical Engineering Department (ENE), Technology College, University of Brasilia (UnB), Brasília-DF 70910-900, Brazil

² Group of Analysis, Security and Systems (GASS), Department of Software Engineering and Artificial Intelligence (DISIA), Faculty of Computer Science and Engineering, Office 431, Universidad Complutense de Madrid (UCM), Calle Profesor José García Santesmases, 9, Ciudad Universitaria, 28040 Madrid, Spain

³ Department of Convergence Security, Sungshin Women’s University, 249-1 Dongseon-Dong 3-ga,Seoul 136-742, Korea

^† These authors contributed equally to this work.

Appl. Sci. 2017, 7(10), 1082; https://doi.org/10.3390/app7101082 - 18 Oct 2017

Cited by 35 | Viewed by 17328

Abstract

Any network connected to the Internet is subject to cyber attacks. Strong security measures, forensic tools, and investigators contribute together to detect and mitigate those attacks, reducing the damages and enabling reestablishing the network to its normal operation, thus increasing the cybersecurity of [...] Read more.

Any network connected to the Internet is subject to cyber attacks. Strong security measures, forensic tools, and investigators contribute together to detect and mitigate those attacks, reducing the damages and enabling reestablishing the network to its normal operation, thus increasing the cybersecurity of the networked environment. This paper addresses the use of a forensic approach with Deep Packet Inspection to detect anomalies in the network traffic. As cyber attacks may occur on any layer of the TCP/IP networking model, Deep Packet Inspection is an effective way to reveal suspicious content in the headers or the payloads in any packet processing layer, excepting of course situations where the payload is encrypted. Although being efficient, this technique still faces big challenges. The contributions of this paper rely on the association of Deep Packet Inspection with forensics analysis to evaluate different attacks towards a Honeynet operating in a network laboratory at the University of Brasilia. In this perspective, this work could identify and map the content and behavior of attacks such as the Mirai botnet and brute-force attacks targeting various different network services. Obtained results demonstrate the behavior of automated attacks (such as worms and bots) and non-automated attacks (brute-force conducted with different tools). The data collected and analyzed is then used to generate statistics of used usernames and passwords, IP and services distribution, among other elements. This paper also discusses the importance of network forensics and Chain of Custody procedures to conduct investigations and shows the effectiveness of the mentioned techniques in evaluating different attacks in networks. Full article

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10 pages, 2960 KiB

Open AccessFeature PaperArticle

Femtosecond Laser-Inscripted Direct Ultrafast Fabrication of a DNA Distributor Using Microfluidics

by Hojun Shin^1,†,‡, Hyojae Kim^2,†, Yeongseok Jang³, Jinmu Jung^4,* and Jonghyun Oh^4,*

¹ Department of Mechanical Engineering and Mechanics, College of Engineering, Drexel University, Philadelphia, PA 19104, USA

² Department of Bionanosystem Engineering, College of Engineering, Chonbuk National University, Jeonju 54896, Korea

³ Department of Mechanical Design Engineering, College of Engineering, Chonbuk National University, Jeonju 54896, Korea

⁴ Department of Nano-bio Mechanical System Engineering, College of Engineering, Chonbuk National University, Jeonju 54896, Korea

^† Two authors were equally contributed to this article.

^‡ Present address: Mechanical Development Group, Samsung SDI Co., LTD., Yongin 17084, Korea.

Appl. Sci. 2017, 7(10), 1083; https://doi.org/10.3390/app7101083 - 19 Oct 2017

Cited by 3 | Viewed by 5165

Abstract

A femtosecond laser can be used for single or multiple writing processes to create sub 10-μm lines or holes directly without the use of masks. In this study, we characterized the depth and width of micro-channels created by femtosecond laser micro-scribing in polydimethylsiloxane [...] Read more.

A femtosecond laser can be used for single or multiple writing processes to create sub 10-μm lines or holes directly without the use of masks. In this study, we characterized the depth and width of micro-channels created by femtosecond laser micro-scribing in polydimethylsiloxane (PDMS) under various energy doses (1%, 5%, 10%, 15% and 20%) and laser beam passes (5, 10 and 15). Based on a microfluidic simulation in a bio-application, a DNA distributor was designed and fabricated based on an energy dose of 5% and a laser beam pass of 5. The simulated depth and width of the micro-channels was 3.58 and 5.27 μm, respectively. The depth and width of the micro-channels were linearly proportional to the energy dose and the number of laser beam passes. In a DNA distribution experiment, a brighter fluorescent intensity for YOYO-1 Iodide with DNA was observed in the middle channels with longer DNA. In addition, the velocity was the lowest as estimated in the computational simulation. The polymer processability of the femtosecond laser and the bio-applicability of the DNA distributor were successfully confirmed. Therefore, a promising technique for the maskless fabrication of sub 10-μm bio-microfluidic channels was demonstrated. Full article

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

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9 pages, 7940 KiB

Open AccessArticle

Fast Method of Recovering Reference-Wave Intensity in Two-Step-Only Quadrature Phase-Shifting Holography

by Wen-Jing Zhou^1,2,*, Caifu Zheng¹ and Ting-Chung Poon^1,2

¹ Department of Precision Mechanical Engineering, Shanghai University, Shanghai 200072, China

² Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24061, USA

Appl. Sci. 2017, 7(10), 1084; https://doi.org/10.3390/app7101084 - 19 Oct 2017

Cited by 1 | Viewed by 4382

Abstract

We present a simple yet effective method, without the need for any additional recording of intensity maps or tremendous iterative computations, to recover reference-wave intensity resulting from the complex hologram acquired by quadrature phase-shifting holography. This is achieved by utilizing a certain area [...] Read more.

We present a simple yet effective method, without the need for any additional recording of intensity maps or tremendous iterative computations, to recover reference-wave intensity resulting from the complex hologram acquired by quadrature phase-shifting holography. This is achieved by utilizing a certain area of interest in the complex hologram. We select a particular area in the complex hologram where there is negligible diffraction from the test sample to estimate the reference-wave intensity. The calculated intensity value allows us to extract exact phase distribution of the object in the context of two-step-only quadrature phase-shifting holography (TSO-PSH) without the zeroth-order beam and the twin image noise on the reconstruction plane. Computer simulation and experimental results have been performed to verify the effectiveness and feasibility of our proposed method. Full article

(This article belongs to the Special Issue Holography and 3D Imaging: Tomorrows Ultimate Experience)

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14 pages, 1648 KiB

Open AccessArticle

Co-Combustion of Fast Pyrolysis Bio-Oil Derived from Coffee Bean Residue and Diesel in an Oil-Fired Furnace

by Shuhn-Shyurng Hou^1,*

, Wei-Cheng Huang¹

and Ta-Hui Lin^2,3,*

¹ Department of Mechanical Engineering, Kun Shan University, Tainan 71070, Taiwan

² Department of Mechanical Engineering, National Cheng Kung University, Tainan 70101, Taiwan

³ Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 70101, Taiwan

Appl. Sci. 2017, 7(10), 1085; https://doi.org/10.3390/app7101085 - 19 Oct 2017

Cited by 16 | Viewed by 5704

Abstract

The combustion characteristics of co-firing bio-oil produced from the fast pyrolysis process of coffee bean residue and diesel in a 300-kW_th oil-fired furnace are investigated. Using bio-oil to completely replace fossil fuels has limitations since bio-oil has undesirable properties, such as high [...] Read more.

The combustion characteristics of co-firing bio-oil produced from the fast pyrolysis process of coffee bean residue and diesel in a 300-kW_th oil-fired furnace are investigated. Using bio-oil to completely replace fossil fuels has limitations since bio-oil has undesirable properties, such as high water and oxygen contents, high viscosity, and low heating value. However, a low blend ratio of bio-oil used as a substitute for petroleum-derived oil has advantages; i.e., it can be easily combusted in existing furnaces without modifications. Thus, a promising solution is the partial substitution of diesel with bio-oil, rather than completely replacing it. A furnace test is performed for diesel alone and bio-oil/diesel blends with 5 vol % bio-oil. The results show that excellent stable combustion is observed during the co-firing test. Compared with diesel, with 5 vol % bio-oil content in the blends, both the wall temperature and gas temperature drop only slightly and exhibit similar furnace temperature distribution; meanwhile, comparable NO emissions (smaller than 57 ppm) are obtained, and lower CO₂ emissions are achieved because biomass is both carbon neutral and renewable. Moreover, SO₂ and CO emissions under these two burning conditions are very low; SO₂ and CO emissions are smaller than 6 and 35 ppm, respectively. Full article

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

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12 pages, 1102 KiB

Open AccessArticle

Optimal Waveform of the Partial-Respond Signal Based on Minimum Out-of-Band Radiation Criterion

by Wenjing Shang¹

, Yidong Xu¹

, Junwei Qi^1,*

, Wei Xue¹ and Sergey B. Makarov²

¹ College of Information and Communication Engineering, Harbin Engineering University, Harbin 150001, China

² Institute of Physics, Nanotechnology and Telecommunications, St. Petersburg State Polytechnical University, St. Petersburg 195251, Russia

Appl. Sci. 2017, 7(10), 1086; https://doi.org/10.3390/app7101086 - 19 Oct 2017

Cited by 4 | Viewed by 3927

Abstract

This paper presents a novel method designing an optimized waveform with high spectral efficiency based on minimum out-of-band radiation criterion. Introducing the Pan-function model, Fourier series, and constraints, we achieve the numeric solution of the optimized baseband signals. The optimal waveform provides an [...] Read more.

This paper presents a novel method designing an optimized waveform with high spectral efficiency based on minimum out-of-band radiation criterion. Introducing the Pan-function model, Fourier series, and constraints, we achieve the numeric solution of the optimized baseband signals. The optimal waveform provides an excellent bandwidth efficiency, and its bit error rate (BER) performance is improved using the minimum cross-correlation function. To verify the proposed model, we present a simulation of the signal modulation and demodulation schemes using MATLAB software. The results are consistent with expected results, verifying the correctness of this method. Full article

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15 pages, 1873 KiB

Open AccessArticle

Analysis of Hydration-Mechanical-Durability Properties of Metakaolin Blended Concrete

by Xiao-Yong Wang

Department of Architectural Engineering, Kangwon National University, Chuncheon-si 200701, Korea

Appl. Sci. 2017, 7(10), 1087; https://doi.org/10.3390/app7101087 - 19 Oct 2017

Cited by 22 | Viewed by 4677

Abstract

Metakaolin (MK) is a highly active pozzolanic material and MK is increasingly used in producing high performance concrete. This study presents an integrated hydration-mechanical-durability model for evaluating various properties of metakaolin blended concrete. First, a blended hydration model is proposed for simulating the [...] Read more.

Metakaolin (MK) is a highly active pozzolanic material and MK is increasingly used in producing high performance concrete. This study presents an integrated hydration-mechanical-durability model for evaluating various properties of metakaolin blended concrete. First, a blended hydration model is proposed for simulating the hydration of composite binders containing MK that considers the dilution effect and pozzolanic reaction due to metakaolin addition. The interactions between the metakaolin reaction and cement hydration were taken into account by means of the contents of calcium hydroxide and capillary water in hydrating the composite binder. The reaction degrees of cement and metakaolin were calculated using the hydration model. Second, the gel-space ratio of the MK blended concrete was determined based on the reaction degrees of the composite binders and proportions of concrete mix. Moreover, concrete compressive strength was calculated using the gel-space ratio. Third, the volumetric phase fractions were calculated based on the reaction degrees of the binders. Chloride penetrability of metakaolin blended concrete was analyzed through the capillary porosity of concrete. The proposed integrated hydration-mechanical-durability model is valuable for the material design of metakaolin blended concrete. Full article

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

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13 pages, 3215 KiB

Open AccessFeature PaperArticle

Research on the Mechanical, Thermal, Induction Heating and Healing Properties of Steel Slag/Steel Fibers Composite Asphalt Mixture

by Quantao Liu^1,2, Bin Li¹, Erik Schlangen^3,*

, Yihan Sun⁴ and Shaopeng Wu^1,*

¹ State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China

² Key Laboratory for highway engineering in special regions of the Education Ministry of China, Chang’an University, Xi’an 710064, China

³ Faculty of Civil Engineering and Geosciences, Micromechanics Laboratory, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands

⁴ Zhejiang Provincial Institute of Communications Planning, Design & Research, Hangzhou 310015, China

Appl. Sci. 2017, 7(10), 1088; https://doi.org/10.3390/app7101088 - 20 Oct 2017

Cited by 61 | Viewed by 5759

Abstract

In this paper, steel slag/steel fiber composite asphalt mixture were prepared. The effects of the addition of steel slag and/or steel fibers on the mechanical, thermal, induction heating and healing properties of asphalt mixture were investigated. The results showed that adding steel slag [...] Read more.

In this paper, steel slag/steel fiber composite asphalt mixture were prepared. The effects of the addition of steel slag and/or steel fibers on the mechanical, thermal, induction heating and healing properties of asphalt mixture were investigated. The results showed that adding steel slag and/or steel fibers improves the water stability, particle loss resistance and fracture energy of asphalt mixtures. The addition of steel fibers increased the thermal conductivity and thermal diffusion of the asphalt mixture, and steel slag showed a reverse effect. Steel slag asphalt mixture cooled more slowly than steel fiber asphalt mixture, which is beneficial to crack healing of asphalt mixture. The composite of steel fibers and steel slag can enhance the induction heating speed, heating homogeneity and thus enhance the induction healing ratio of asphalt mixture. It is concluded that steel slag/steel fibers composite asphalt mixture achieves good mechanical and induction healing properties. Full article

(This article belongs to the Special Issue Self-Healing Asphalt)

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15 pages, 16316 KiB

Open AccessArticle

A High-Dynamic-Range Optical Remote Sensing Imaging Method for Digital TDI CMOS

by Taiji Lan^1,2,*, Xucheng Xue¹, Junlin Li¹, Chengshan Han¹ and Kehui Long¹

¹ Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China

² University of Chinese Academy of Sciences, Beijing 100049, China

Appl. Sci. 2017, 7(10), 1089; https://doi.org/10.3390/app7101089 - 20 Oct 2017

Cited by 11 | Viewed by 5841

Abstract

The digital time delay integration (digital TDI) technology of the complementary metal-oxide-semiconductor (CMOS) image sensor has been widely adopted and developed in the optical remote sensing field. However, the details of targets that have low illumination or low contrast in scenarios of high [...] Read more.

The digital time delay integration (digital TDI) technology of the complementary metal-oxide-semiconductor (CMOS) image sensor has been widely adopted and developed in the optical remote sensing field. However, the details of targets that have low illumination or low contrast in scenarios of high contrast are often drowned out because of the superposition of multi-stage images in digital domain multiplies the read noise and the dark noise, thus limiting the imaging dynamic range. Through an in-depth analysis of the information transfer model of digital TDI, this paper attempts to explore effective ways to overcome this issue. Based on the evaluation and analysis of multi-stage images, the entropy-maximized adaptive histogram equalization (EMAHE) algorithm is proposed to improve the ability of images to express the details of dark or low-contrast targets. Furthermore, in this paper, an image fusion method is utilized based on gradient pyramid decomposition and entropy weighting of different TDI stage images, which can improve the detection ability of the digital TDI CMOS for complex scenes with high contrast, and obtain images that are suitable for recognition by the human eye. The experimental results show that the proposed methods can effectively improve the high-dynamic-range imaging (HDRI) capability of the digital TDI CMOS. The obtained images have greater entropy and average gradients. Full article

(This article belongs to the Section Optics and Lasers)

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15 pages, 3766 KiB

Open AccessArticle

Characterization and Use of Construction and Demolition Waste from South of Brazil in the Production of Foamed Concrete Blocks

by Patrícia Favaretto¹, Gelsa Edith Navarro Hidalgo², Carlos Hoffmann Sampaio², Rodrigo De Almeida Silva¹

and Richard Thomas Lermen^1,*

¹ Post-Graduation Program in Civil Engineering (PPGEC), Department of Civil Engineering, Polytechnic School, Meridional College (IMED), Passo Fundo, Rio Grande do Sul 99070-220, Brazil

² Laboratory of Mineral Processing (LAPROM), Post-Graduation Program in Mining, Metallurgical and Materials Engineering (PPGE3M), Department of Engineering, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul 90130-120, Brazil

Appl. Sci. 2017, 7(10), 1090; https://doi.org/10.3390/app7101090 - 21 Oct 2017

Cited by 58 | Viewed by 7695

Abstract

The main objective of this study was to evaluate the use of construction and demolition waste (CDW) from the Passo Fundo region of Rio Grande do Sul (RS), Brazil, in the development of aerated foamed concrete. This waste had not yet been characterized [...] Read more.

The main objective of this study was to evaluate the use of construction and demolition waste (CDW) from the Passo Fundo region of Rio Grande do Sul (RS), Brazil, in the development of aerated foamed concrete. This waste had not yet been characterized or even reused. CDW was processed (sieved only), characterized, and used as an aggregate, completely substituting natural sand. The influence of CDW granulometry and the amount of foam upon compressive strength, wet and dry bulk density, water absorption, and the air voids of concrete blocks were determined. Results showed that CDW has regular characteristics for the development of aerated foamed concrete. Compressive strength and density decreased as the amount of foam increased, while water absorption and air voids also increased. Also, CDW that was classified as coarse showed higher compressive strength. On average, CDW medium-sized particles had a higher air void content, while water absorption showed little variation with respect to granulometry. CDW residue from the region of study can be used as aggregate for the development of aerated foamed concrete. However, it must characterized before being used to guarantee the quality of the final product. Full article

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

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14 pages, 4926 KiB

Open AccessArticle

Hybrid Prediction Model of the Temperature Field of a Motorized Spindle

by Lixiu Zhang¹, Chaoqun Li², Yuhou Wu², Ke Zhang² and Huaitao Shi^2,*

¹ Test and Analysis Center, Shenyang Jianzhu University, No. 9, Hunnan East Road, Hunnan New District, Shenyang 110168, China

² School of Mechanical Engineering, Shenyang Jianzhu University, No. 9, Hunnan East Road, Hunnan New District, Shenyang 110168, China

Appl. Sci. 2017, 7(10), 1091; https://doi.org/10.3390/app7101091 - 22 Oct 2017

Cited by 22 | Viewed by 6279

Abstract

The thermal characteristics of a motorized spindle are the main determinants of its performance, and influence the machining accuracy of computer numerical control machine tools. It is important to accurately predict the thermal field of a motorized spindle during its operation to improve [...] Read more.

The thermal characteristics of a motorized spindle are the main determinants of its performance, and influence the machining accuracy of computer numerical control machine tools. It is important to accurately predict the thermal field of a motorized spindle during its operation to improve its thermal characteristics. This paper proposes a model to predict the temperature field of a high-speed and high-precision motorized spindle under different working conditions using a finite element model and test data. The finite element model considers the influence of the parameters of the cooling system and the lubrication system, and that of environmental conditions on the coefficient of heat transfer based on test data for the surface temperature of the motorized spindle. A genetic algorithm is used to optimize the coefficient of heat transfer of the spindle, and its temperature field is predicted using a three-dimensional model that employs this optimal coefficient. A prediction model of the 170MD30 temperature field of the motorized spindle is created and simulation data for the temperature field are compared with the test data. The results show that when the speed of the spindle is 10,000 rpm, the relative mean prediction error is 1.5%, and when its speed is 15,000 rpm, the prediction error is 3.6%. Therefore, the proposed prediction model can predict the temperature field of the motorized spindle with high accuracy. Full article

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

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15 pages, 14137 KiB

Open AccessArticle

T-Spline Based Unifying Registration Procedure for Free-Form Surface Workpieces in Intelligent CMM

by Zhenhua Han¹

, Yingmo Wang¹, Xinhui Ma²

, Shugui Liu¹, Xiaodong Zhang^1,* and Guoxiong Zhang¹

¹ State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin 300072, China

² School of Engineering and Computer Science, University of Hull, Hull HU6 7RX, UK

Appl. Sci. 2017, 7(10), 1092; https://doi.org/10.3390/app7101092 - 23 Oct 2017

Cited by 6 | Viewed by 5549

Abstract

With the development of the modern manufacturing industry, the free-form surface is widely used in various fields, and the automatic detection of a free-form surface is an important function of future intelligent three-coordinate measuring machines (CMMs). To improve the intelligence of CMMs, a [...] Read more.

With the development of the modern manufacturing industry, the free-form surface is widely used in various fields, and the automatic detection of a free-form surface is an important function of future intelligent three-coordinate measuring machines (CMMs). To improve the intelligence of CMMs, a new visual system is designed based on the characteristics of CMMs. A unified model of the free-form surface is proposed based on T-splines. A discretization method of the T-spline surface formula model is proposed. Under this discretization, the position and orientation of the workpiece would be recognized by point cloud registration. A high accuracy evaluation method is proposed between the measured point cloud and the T-spline surface formula. The experimental results demonstrate that the proposed method has the potential to realize the automatic detection of different free-form surfaces and improve the intelligence of CMMs. Full article

(This article belongs to the Section Mechanical Engineering)

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29 pages, 23228 KiB

Open AccessArticle

Fracture Initiation of an Inhomogeneous Shale Rock under a Pressurized Supercritical CO₂ Jet

by Yi Hu^1,2,3

, Yiwei Liu^1,2,4,*, Can Cai^1,2,3, Yong Kang^1,2,3, Xiaochuan Wang^1,2,3

, Man Huang^1,2,3 and Feng Chen^1,2,4

¹ Key Laboratory of Hydraulic Machinery Transients, Ministry of Education, Wuhan University, Wuhan 430072, China

² Hubei Key Laboratory of Waterjet Theory and New Technology, Wuhan University, Wuhan 430072, China

³ School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China

⁴ School of Civil Engineering, Wuhan University, Wuhan 430072, China

Appl. Sci. 2017, 7(10), 1093; https://doi.org/10.3390/app7101093 - 23 Oct 2017

Cited by 20 | Viewed by 5230

Abstract

Due to the advantages of good fracture performance and the application of carbon capture and storage (CCS), supercritical carbon dioxide (SC-CO₂) is considered a promising alternative for hydraulic fracturing. However, the fracture initiation mechanism and its propagation under pressurized SC-CO₂ [...] Read more.

Due to the advantages of good fracture performance and the application of carbon capture and storage (CCS), supercritical carbon dioxide (SC-CO₂) is considered a promising alternative for hydraulic fracturing. However, the fracture initiation mechanism and its propagation under pressurized SC-CO₂ jet are still unknown. To address these problems, a fluid–structure interaction (FSI)-based numerical simulation model along with a user-defined code was used to investigate the fracture initiation in an inhomogeneous shale rock. The mechanism of fracturing under the effect of SC-CO₂ jet was explored, and the effects of various influencing factors were analyzed and discussed. The results indicated that higher velocity jets of SC-CO₂ not only caused hydraulic-fracturing ring, but also resulted in the increase of stress in the shale rock. It was found that, with the increase of perforation pressure, more cracks initiated at the tip. In contrast, the length of cracks at the root decreased. The length-to-diameter ratio and the aperture ratio distinctly affected the pressurization of SC-CO₂ jet, and contributed to the non-linear distribution and various maximum values of the stress in shale rock. The results proved that Weibull probability distribution was appropriate for analysis of the fracture initiation. The studied parameters explain the distribution of weak elements, and they affect the stress field in shale rock. Full article

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

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10 pages, 1340 KiB

Open AccessArticle

Effect of ZnO Addition and of Alpha Particle Irradiation on Various Properties of Er³⁺, Yb³⁺ Doped Phosphate Glasses

by Arun Poudel¹, Iuliia Dmitrieva¹, Regina Gumenyuk¹, Laura Mihai²

, Dan Sporea², Ofelia Mureşan³, Ion Rusen³, Teemu Hakkarainen¹, Nadia G. Boetti⁴

, Tapio Niemi¹ and Laeticia Petit^1,*

¹ Laboratory of Photonics, Tampere University of Technology, Korkeakoulunkatu 3, 33720 Tampere, Finland

² National Institute for Laser, Plasma and Radiation Physics, Center for Advanced Laser Technologies, Măgurele RO-077125, Romania

³ “Horia Hulubei” National Institute of Physics and Nuclear Engineering, Măgurele RO-077125, Romania

⁴ Istituto Superiore Mario Boella, Via P. C. Boggio 61, 10138 Torino, Italy

Appl. Sci. 2017, 7(10), 1094; https://doi.org/10.3390/app7101094 - 24 Oct 2017

Cited by 9 | Viewed by 4364

Abstract

New Er³⁺, Yb³⁺ codoped phosphate glasses with the (98-x) (0.50P₂O₅-0.40SrO-0.10Na₂O) -0.5Er₂O₃-1.5Yb₂O₃-xZnO (in mol %) composition were prepared by melting process with up to 10 mol % [...] Read more.

New Er³⁺, Yb³⁺ codoped phosphate glasses with the (98-x) (0.50P₂O₅-0.40SrO-0.10Na₂O) -0.5Er₂O₃-1.5Yb₂O₃-xZnO (in mol %) composition were prepared by melting process with up to 10 mol % of ZnO. The impact of the changes in the glass composition on the thermal, optical, structural properties was investigated. Using IR and Raman spectroscopies, we confirmed that the addition of ZnO up to 10 mol % leads to a depolymerization of the network without having a significant impact on the Er³⁺ and Yb³⁺ sites. We also discuss the effect of alpha particles irradiation. The glass with 2.5 mol % of ZnO was irradiated with 3 MeV alpha particles and a total fluence of 10¹² α/cm². After irradiation, this glass exhibits surface expansion (measured at ~200 nm, 1.5 months after the irradiation) and an increase in the surface roughness. The alpha particles irradiation is suspected to lead to changes in the spectroscopic properties of the glass. Finally, the photo-response of the glass was found to be reversible. Full article

(This article belongs to the Special Issue Rare-Earth Doping for Optical Applications)

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24 pages, 1973 KiB

Open AccessArticle

A Lookahead Behavior Model for Multi-Agent Hybrid Simulation

by Mei Yang^*, Yong Peng, Ru-Sheng Ju, Xiao Xu, Quan-Jun Yin and Ke-Di Huang

College of Information System and Management, National University of Defense Technology, Changsha 410073, Hunan, China

Appl. Sci. 2017, 7(10), 1095; https://doi.org/10.3390/app7101095 - 24 Oct 2017

Cited by 3 | Viewed by 4847

Abstract

In the military field, multi-agent simulation (MAS) plays an important role in studying wars statistically. For a military simulation system, which involves large-scale entities and generates a very large number of interactions during the runtime, the issue of how to improve the running [...] Read more.

In the military field, multi-agent simulation (MAS) plays an important role in studying wars statistically. For a military simulation system, which involves large-scale entities and generates a very large number of interactions during the runtime, the issue of how to improve the running efficiency is of great concern for researchers. Current solutions mainly use hybrid simulation to gain fewer updates and synchronizations, where some important continuous models are maintained implicitly to keep the system dynamics, and partial resynchronization (PR) is chosen as the preferable state update mechanism. However, problems, such as resynchronization interval selection and cyclic dependency, remain unsolved in PR, which easily lead to low update efficiency and infinite looping of the state update process. To address these problems, this paper proposes a lookahead behavior model (LBM) to implement a PR-based hybrid simulation. In LBM, a minimal safe time window is used to predict the interactions between implicit models, upon which the resynchronization interval can be efficiently determined. Moreover, the LBM gives an estimated state value in the lookahead process so as to break the state-dependent cycle. The simulation results show that, compared with traditional mechanisms, LBM requires fewer updates and synchronizations. Full article

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

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15 pages, 441 KiB

Open AccessArticle

A Transparent Decision Support Tool in Screening for Laryngeal Disorders Using Voice and Query Data

by Jonas Minelga¹, Antanas Verikas^1,2,*

, Evaldas Vaiciukynas¹, Adas Gelzinis¹ and Marija Bacauskiene¹

¹ Department of Electric Power Systems, Kaunas University of Technology, Studentu 50, LT-51368 Kaunas, Lithuania

² Centre for Applied Intelligent Systems Research, Halmstad University, Kristian IV:s väg 3, P.O. Box 823, S-30118 Halmstad, Sweden

Appl. Sci. 2017, 7(10), 1096; https://doi.org/10.3390/app7101096 - 24 Oct 2017

Cited by 1 | Viewed by 4940

Abstract

The aim of this study is a transparent tool for analysis of voice (sustained phonation /a/) and query data capable of providing support in screening for laryngeal disorders. In this work, screening is concerned with identification of potentially pathological cases by [...] Read more.

The aim of this study is a transparent tool for analysis of voice (sustained phonation /a/) and query data capable of providing support in screening for laryngeal disorders. In this work, screening is concerned with identification of potentially pathological cases by classifying subject’s data into ’healthy’ and ’pathological’ classes as well as visual exploration of data and automatic decisions. A set of association rules and a decision tree, techniques lending themselves for exploration, were generated for pathology detection. Data pairwise similarities, estimated in a novel way, were mapped onto a 2D metric space for visual inspection and analysis. Accurate identification of pathological cases was observed on unseen subjects using the most discriminative query parameter and six audio parameters routinely used by otolaryngologists in a clinical practice: equal error rate (EER) of 11.1% was achieved using association rules and 10.2% using the decision tree. The EER was further reduced to 9.5% by combining results from these two classifiers. The developed solution can be a useful tool for Otolaryngology departments in diagnostics, education and exploratory tasks. Full article

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12 pages, 2849 KiB

Open AccessArticle

Feature Selection and Classification of Ulcerated Lesions Using Statistical Analysis for WCE Images

by Shipra Suman^1,*, Fawnizu Azmadi Hussin¹, Aamir Saeed Malik¹, Shiaw Hooi Ho², Ida Hilmi², Alex Hwong-Ruey Leow² and Khean-Lee Goh²

¹ Center for Intelligent Signal & Imaging Research, Universiti Teknologi PETRONAS, Seri Iskandar 32610, Malaysia

² Department of Medicine, University of Malaya Medical Center, Kuala Lumpur 50603, Malaysia

Appl. Sci. 2017, 7(10), 1097; https://doi.org/10.3390/app7101097 - 24 Oct 2017

Cited by 34 | Viewed by 6188

Abstract

Wireless capsule endoscopy (WCE) is a technology developed to inspect the whole gastrointestinal tract (especially the small bowel area that is unreachable using the traditional endoscopy procedure) for various abnormalities in a non-invasive manner. However, visualization of a massive number of images is [...] Read more.

Wireless capsule endoscopy (WCE) is a technology developed to inspect the whole gastrointestinal tract (especially the small bowel area that is unreachable using the traditional endoscopy procedure) for various abnormalities in a non-invasive manner. However, visualization of a massive number of images is a very time-consuming and tedious task for physicians (prone to human error). Thus, an automatic scheme for lesion detection in WCE videos is a potential solution to alleviate this problem. In this work, a novel statistical approach was chosen for differentiating ulcer and non-ulcer pixels using various color spaces (or more specifically using relevant color bands). The chosen feature vector was used to compute the performance metrics using SVM with grid search method for maximum efficiency. The experimental results and analysis showed that the proposed algorithm was robust in detecting ulcers. The performance in terms of accuracy, sensitivity, and specificity are 97.89%, 96.22%, and 95.09%, respectively, which is promising. Full article

(This article belongs to the Special Issue Smart Healthcare)

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15 pages, 7068 KiB

Open AccessArticle

Contrast-Enhanced Ultrasound Imaging Based on Bubble Region Detection

by Yurong Huang^1,†, Jinhua Yu^1,2,3,*, Yusheng Tong^3,4,†, Shuying Li¹, Liang Chen^3,4,*, Yuanyuan Wang^1,2 and Qi Zhang⁵

¹ Department of Electronic Engineering, Fudan University, Shanghai 200433, China

² Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention of Shanghai, Shanghai 200433, China

³ Institute of Functional and Molecular Medical Imaging, Fudan University, Shanghai 200030, China

⁴ Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai 200030, China

⁵ School of Communication and Information Engineering, Shanghai University, Shanghai 200444, China

^† Those authors contributed equally to this work.

Appl. Sci. 2017, 7(10), 1098; https://doi.org/10.3390/app7101098 - 24 Oct 2017

Cited by 4 | Viewed by 5151

Abstract

The study of ultrasound contrast agent imaging (USCAI) based on plane waves has recently attracted increasing attention. A series of USCAI techniques have been developed to improve the imaging quality. Most of the existing methods enhance the contrast-to-tissue ratio (CTR) using the time-frequency [...] Read more.

The study of ultrasound contrast agent imaging (USCAI) based on plane waves has recently attracted increasing attention. A series of USCAI techniques have been developed to improve the imaging quality. Most of the existing methods enhance the contrast-to-tissue ratio (CTR) using the time-frequency spectrum differences between the tissue and ultrasound contrast agent (UCA) region. In this paper, a new USCAI method based on bubble region detection was proposed, in which the frequency difference as well as the dissimilarity of tissue and UCA in the spatial domain was taken into account. A bubble wavelet based on the Doinikov model was firstly constructed. Bubble wavelet transformation (BWT) was then applied to strengthen the UCA region and weaken the tissue region. The bubble region was thereafter detected by using the combination of eigenvalue and eigenspace-based coherence factor (ESBCF). The phantom and rabbit in vivo experiment results suggested that our method was capable of suppressing the background interference and strengthening the information of UCA. For the phantom experiment, the imaging CTR was improved by 10.1 dB compared with plane wave imaging based on delay-and-sum (DAS) and by 4.2 dB over imaging based on BWT on average. Furthermore, for the rabbit kidney experiment, the corresponding improvements were 18.0 dB and 3.4 dB, respectively. Full article

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

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10 pages, 2680 KiB

Open AccessArticle

Amorphous Oxide Thin Film Transistors with Nitrogen-Doped Hetero-Structure Channel Layers

by Haiting Xie, Guochao Liu, Lei Zhang, Yan Zhou and Chengyuan Dong^*

Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

Appl. Sci. 2017, 7(10), 1099; https://doi.org/10.3390/app7101099 - 24 Oct 2017

Cited by 21 | Viewed by 8816

Abstract

The nitrogen-doped amorphous oxide semiconductor (AOS) thinfilm transistors (TFTs) with double-stacked channel layers (DSCL) were prepared and characterized. The DSCL structure was composed of nitrogen-doped amorphous InGaZnO and InZnO films (a-IGZO:N/a-IZO:N or a-IZO:N/a-IGZO:N) and gave the corresponding TFT devices large field-effect mobility due [...] Read more.

The nitrogen-doped amorphous oxide semiconductor (AOS) thinfilm transistors (TFTs) with double-stacked channel layers (DSCL) were prepared and characterized. The DSCL structure was composed of nitrogen-doped amorphous InGaZnO and InZnO films (a-IGZO:N/a-IZO:N or a-IZO:N/a-IGZO:N) and gave the corresponding TFT devices large field-effect mobility due to the presence of double conduction channels. The a-IZO:N/a-IGZO:N TFTs, in particular, showed even better electrical performance (µ_FE = 15.0 cm²・V⁻¹・s⁻¹, SS = 0.5 V/dec, V_TH = 1.5 V, I_ON/I_OFF = 1.1 × 10⁸) and stability (V_TH shift of 1.5, −0.5 and −2.5 V for positive bias-stress, negative bias-stress, and thermal stress tests, respectively) than the a-IGZO:N/a-IZO:N TFTs. Based on the X-ray photoemission spectroscopy measurements and energy band analysis, we assumed that the optimized interface trap states, the less ambient gas adsorption, and the better suppression of oxygen vacancies in the a-IZO:N/a-IGZO:N hetero-structures might explain the better behavior of the corresponding TFTs. Full article

(This article belongs to the Special Issue Thin-Film Transistor)

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16 pages, 3883 KiB

Open AccessArticle

A Stochastic Bi-Level Scheduling Approach for the Participation of EV Aggregators in Competitive Electricity Markets

by Homa Rashidizadeh-Kermani¹, Mostafa Vahedipour-Dahraie¹, Hamid Reza Najafi^1,*, Amjad Anvari-Moghaddam²

and Josep M. Guerrero²

¹ Department of Electrical & Computer Engineering, University of Birjand, 9856 Birjand, Iran

² Department of Energy Technology, Aalborg University, 9220 Aalborg East, Denmark

Appl. Sci. 2017, 7(10), 1100; https://doi.org/10.3390/app7101100 - 24 Oct 2017

Cited by 41 | Viewed by 4948

Abstract

This paper proposes a stochastic bi-level decision-making model for an electric vehicle (EV) aggregator in a competitive environment. In this approach, the EV aggregator decides to participate in day-ahead (DA) and balancing markets, and provides energy price offers to the EV owners in [...] Read more.

This paper proposes a stochastic bi-level decision-making model for an electric vehicle (EV) aggregator in a competitive environment. In this approach, the EV aggregator decides to participate in day-ahead (DA) and balancing markets, and provides energy price offers to the EV owners in order to maximize its expected profit. Moreover, from the EV owners’ viewpoint, energy procurement cost of their EVs should be minimized in an uncertain environment. In this study, the sources of uncertainty―including the EVs demand, DA and balancing prices and selling prices offered by rival aggregators―are modeled via stochastic programming. Therefore, a two-level problem is formulated here, in which the aggregator makes decisions in the upper level and the EV clients purchase energy to charge their EVs in the lower level. Then the obtained nonlinear bi-level framework is transformed into a single-level model using Karush–Kuhn–Tucker (KKT) optimality conditions. Strong duality is also applied to the problem to linearize the bilinear products. To deal with the unwilling effects of uncertain resources, a risk measurement is also applied in the proposed formulation. The performance of the proposed framework is assessed in a realistic case study and the results show that the proposed model would be effective for an EV aggregator decision-making problem in a competitive environment. Full article

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

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19 pages, 541 KiB

Open AccessArticle

UniMiB SHAR: A Dataset for Human Activity Recognition Using Acceleration Data from Smartphones

by Daniela Micucci

, Marco Mobilio

and Paolo Napoletano^*

Department of Informatics, System and Communication, University of Milano Bicocca, Viale Sarca 336, 20126 Milan, Italy

Appl. Sci. 2017, 7(10), 1101; https://doi.org/10.3390/app7101101 - 24 Oct 2017

Cited by 488 | Viewed by 23141

Abstract

Smartphones, smartwatches, fitness trackers, and ad-hoc wearable devices are being increasingly used to monitor human activities. Data acquired by the hosted sensors are usually processed by machine-learning-based algorithms to classify human activities. The success of those algorithms mostly depends on the availability of [...] Read more.

Smartphones, smartwatches, fitness trackers, and ad-hoc wearable devices are being increasingly used to monitor human activities. Data acquired by the hosted sensors are usually processed by machine-learning-based algorithms to classify human activities. The success of those algorithms mostly depends on the availability of training (labeled) data that, if made publicly available, would allow researchers to make objective comparisons between techniques. Nowadays, there are only a few publicly available data sets, which often contain samples from subjects with too similar characteristics, and very often lack specific information so that is not possible to select subsets of samples according to specific criteria. In this article, we present a new dataset of acceleration samples acquired with an Android smartphone designed for human activity recognition and fall detection. The dataset includes 11,771 samples of both human activities and falls performed by 30 subjects of ages ranging from 18 to 60 years. Samples are divided in 17 fine grained classes grouped in two coarse grained classes: one containing samples of 9 types of activities of daily living (ADL) and the other containing samples of 8 types of falls. The dataset has been stored to include all the information useful to select samples according to different criteria, such as the type of ADL performed, the age, the gender, and so on. Finally, the dataset has been benchmarked with four different classifiers and with two different feature vectors. We evaluated four different classification tasks: fall vs. no fall, 9 activities, 8 falls, 17 activities and falls. For each classification task, we performed a 5-fold cross-validation (i.e., including samples from all the subjects in both the training and the test dataset) and a leave-one-subject-out cross-validation (i.e., the test data include the samples of a subject only, and the training data, the samples of all the other subjects). Regarding the classification tasks, the major findings can be summarized as follows: (i) it is quite easy to distinguish between falls and ADLs, regardless of the classifier and the feature vector selected. Indeed, these classes of activities present quite different acceleration shapes that simplify the recognition task; (ii) on average, it is more difficult to distinguish between types of falls than between types of activities, regardless of the classifier and the feature vector selected. This is due to the similarity between the acceleration shapes of different kinds of falls. On the contrary, ADLs acceleration shapes present differences except for a small group. Finally, the evaluation shows that the presence of samples of the same subject both in the training and in the test datasets, increases the performance of the classifiers regardless of the feature vector used. This happens because each human subject differs from other subjects in performing activities even if she shares with them the same physical characteristics. Full article

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25 pages, 9624 KiB

Open AccessReview

A Review of Three-Dimensional Scanning Near-Field Optical Microscopy (3D-SNOM) and Its Applications in Nanoscale Light Management

by Paul Bazylewski, Sabastine Ezugwu

and Giovanni Fanchini^*

Department of Physics and Astronomy, University of Western Ontario, London, ON N6A3K7, Canada

Appl. Sci. 2017, 7(10), 973; https://doi.org/10.3390/app7100973 - 22 Sep 2017

Cited by 98 | Viewed by 17833

Abstract

In this article, we present an overview of aperture and apertureless type scanning near-field optical microscopy (SNOM) techniques that have been developed, with a focus on three-dimensional (3D) SNOM methods. 3D SNOM has been undertaken to image the local distribution (within ~100 nm [...] Read more.

In this article, we present an overview of aperture and apertureless type scanning near-field optical microscopy (SNOM) techniques that have been developed, with a focus on three-dimensional (3D) SNOM methods. 3D SNOM has been undertaken to image the local distribution (within ~100 nm of the surface) of the electromagnetic radiation scattered by random and deterministic arrays of metal nanostructures or photonic crystal waveguides. Individual metal nanoparticles and metal nanoparticle arrays exhibit unique effects under light illumination, including plasmon resonance and waveguiding properties, which can be directly investigated using 3D-SNOM. In the second part of this article, we will review a few applications in which 3D-SNOM has proven to be useful for designing and understanding specific nano-optoelectronic structures. Examples include the analysis of the nano-optical response phonetic crystal waveguides, aperture antennae and metal nanoparticle arrays, as well as the design of plasmonic solar cells incorporating random arrays of copper nanoparticles as an optical absorption enhancement layer, and the use of 3D-SNOM to probe multiple components of the electric and magnetic near-fields without requiring specially designed probe tips. A common denominator of these examples is the added value provided by 3D-SNOM in predicting the properties-performance relationship of nanostructured systems. Full article

(This article belongs to the Special Issue Light Management for Optoelectronics)

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17 pages, 2421 KiB

Open AccessFeature PaperReview

An Overview of Smart Shoes in the Internet of Health Things: Gait and Mobility Assessment in Health Promotion and Disease Monitoring

by Bjoern M. Eskofier^1,*

, Sunghoon Ivan Lee², Manuela Baron¹, André Simon¹, Christine F. Martindale¹

, Heiko Gaßner³ and Jochen Klucken³

¹ Machine Learning and Data Analytics Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Immerwahrstrasse 2a, 91058 Erlangen, Germany

² College of Information and Computer Sciences, University of Massachusetts, Amherst, MA 01003, USA

³ Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany

Appl. Sci. 2017, 7(10), 986; https://doi.org/10.3390/app7100986 - 25 Sep 2017

Cited by 120 | Viewed by 21684

Abstract

New smart technologies and the internet of things increasingly play a key role in healthcare and wellness, contributing to the development of novel healthcare concepts. These technologies enable a comprehensive view of an individual’s movement and mobility, potentially supporting healthy living as well [...] Read more.

New smart technologies and the internet of things increasingly play a key role in healthcare and wellness, contributing to the development of novel healthcare concepts. These technologies enable a comprehensive view of an individual’s movement and mobility, potentially supporting healthy living as well as complementing medical diagnostics and the monitoring of therapeutic outcomes. This overview article specifically addresses smart shoes, which are becoming one such smart technology within the future internet of health things, since the ability to walk defines large aspects of quality of life in a wide range of health and disease conditions. Smart shoes offer the possibility to support prevention, diagnostic work-up, therapeutic decisions, and individual disease monitoring with a continuous assessment of gait and mobility. This overview article provides the technological as well as medical aspects of smart shoes within this rising area of digital health applications, and is designed especially for the novel reader in this specific field. It also stresses the need for closer interdisciplinary interactions between technological and medical experts to bridge the gap between research and practice. Smart shoes can be envisioned to serve as pervasive wearable computing systems that enable innovative solutions and services for the promotion of healthy living and the transformation of health care. Full article

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

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19 pages, 6302 KiB

Open AccessReview

Pulsed Thermography Applied to the Study of Cultural Heritage

by Fulvio Mercuri, Noemi Orazi

, Stefano Paoloni^*, Cristina Cicero and Ugo Zammit

Dipartimento di Ingegneria Industriale, Università degli Studi di Roma Tor Vergata, via del Politecnico 1, 00133 Roma, Italy

Appl. Sci. 2017, 7(10), 1010; https://doi.org/10.3390/app7101010 - 29 Sep 2017

Cited by 54 | Viewed by 7330

Abstract

In this paper, an overview of the recent applications of pulsed infrared thermography is presented. Pulsed infrared thermography, which provides stratigraphic information by analyzing the heat diffusion process within the sample after a thermal perturbation, is applied to the investigation of different kinds [...] Read more.

In this paper, an overview of the recent applications of pulsed infrared thermography is presented. Pulsed infrared thermography, which provides stratigraphic information by analyzing the heat diffusion process within the sample after a thermal perturbation, is applied to the investigation of different kinds of cultural heritage artefacts. In particular, it is used to analyze repairs, decorative elements, and casting faults on bronzes, to detect texts hidden or damaged in ancient books/documents, and to characterize paint decorations. Moreover, the integration of pulsed infrared thermography and three-dimensional shape recording methods is proposed in order to provide a three-dimensional representation of the thermographic results. Finally, it is shown how the obtained thermographic results may be crucial from the historical and artistic points of view for understanding the modus operandi of a specific artist and/or of a workshop and for reconstructing the manufacturing process of the analyzed artefacts. Full article

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

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26 pages, 3080 KiB

Open AccessReview

Cyber–Physical–Social Frameworks for Urban Big Data Systems: A Survey

by Suparna De^1,*

, Yuchao Zhou¹, Iker Larizgoitia Abad² and Klaus Moessner¹

¹ Institute for Communication Systems (ICS), University of Surrey, Guildford GU2 7XH, UK

² Evrythng Limited, Unit 4, 122 East Road, London N1 6FB, UK

Appl. Sci. 2017, 7(10), 1017; https://doi.org/10.3390/app7101017 - 2 Oct 2017

Cited by 65 | Viewed by 11121

Abstract

The integration of things’ data on the Web and Web linking for things’ description and discovery is leading the way towards smart Cyber–Physical Systems (CPS). The data generated in CPS represents observations gathered by sensor devices about the ambient environment that can be [...] Read more.

The integration of things’ data on the Web and Web linking for things’ description and discovery is leading the way towards smart Cyber–Physical Systems (CPS). The data generated in CPS represents observations gathered by sensor devices about the ambient environment that can be manipulated by computational processes of the cyber world. Alongside this, the growing use of social networks offers near real-time citizen sensing capabilities as a complementary information source. The resulting Cyber–Physical–Social System (CPSS) can help to understand the real world and provide proactive services to users. The nature of CPSS data brings new requirements and challenges to different stages of data manipulation, including identification of data sources, processing and fusion of different types and scales of data. To gain an understanding of the existing methods and techniques which can be useful for a data-oriented CPSS implementation, this paper presents a survey of the existing research and commercial solutions. We define a conceptual framework for a data-oriented CPSS and detail the various solutions for building human–machine intelligence. Full article

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32 pages, 9489 KiB

Open AccessFeature PaperReview

The Challenges of Advanced CMOS Process from 2D to 3D

by Henry H. Radamson^1,2,3,*,†, Yanbo Zhang^1,†, Xiaobin He^1,†, Hushan Cui^1,†, Junjie Li^1,†

, Jinjuan Xiang^1,†, Jinbiao Liu^1,†, Shihai Gu^1,† and Guilei Wang^1,2,*,†

¹ Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China

² Microelectronics Institute, University of Chinese Academy of Sciences, Beijing 100049, China

³ School of ICT, KTH Royal Institute of Technology, Isafjordsgatan 22, 16440 Stockholm, Sweden

^† The authors have equally contributed in this article.

Appl. Sci. 2017, 7(10), 1047; https://doi.org/10.3390/app7101047 - 13 Oct 2017

Cited by 68 | Viewed by 22377

Abstract

The architecture, size and density of metal oxide field effect transistors (MOSFETs) as unit bricks in integrated circuits (ICs) have constantly changed during the past five decades. The driving force for such scientific and technological development is to reduce the production price, power [...] Read more.

The architecture, size and density of metal oxide field effect transistors (MOSFETs) as unit bricks in integrated circuits (ICs) have constantly changed during the past five decades. The driving force for such scientific and technological development is to reduce the production price, power consumption and faster carrier transport in the transistor channel. Therefore, many challenges and difficulties have been merged in the processing of transistors which have to be dealed and solved. This article highlights the transition from 2D planar MOSFETs to 3D fin field effective transistors (FinFETs) and then presents how the process flow faces different technological challenges. The discussions contain nano-scaled patterning and process issues related to gate and (source/drain) S/D formation as well as integration of III-V materials for high carrier mobility in channel for future FinFETs. Full article

(This article belongs to the Section Nanotechnology and Applied Nanosciences)

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31 pages, 487 KiB

Open AccessReview

Technology-Facilitated Diagnosis and Treatment of Individuals with Autism Spectrum Disorder: An Engineering Perspective

by Xiongyi Liu¹, Qing Wu², Wenbing Zhao^2,*

and Xiong Luo³

¹ Department of Curriculum and Foundations, Cleveland State University, Cleveland, OH 44115, USA

² Department of Electrical Engineering and Computer Science, Cleveland State University, Cleveland, OH 44115, USA

³ School of Computer and Communication Engineering, University of Science and Technology Beijing, Beijing 100083, China

Appl. Sci. 2017, 7(10), 1051; https://doi.org/10.3390/app7101051 - 13 Oct 2017

Cited by 63 | Viewed by 11291

Abstract

The rapid development of computer and robotic technologies in the last decade is giving hope to perform earlier and more accurate diagnoses of the Autism Spectrum Disorder (ASD), and more effective, consistent, and cost-conscious treatment. Besides the reduced cost, the main benefit of [...] Read more.

The rapid development of computer and robotic technologies in the last decade is giving hope to perform earlier and more accurate diagnoses of the Autism Spectrum Disorder (ASD), and more effective, consistent, and cost-conscious treatment. Besides the reduced cost, the main benefit of using technology to facilitate treatment is that stimuli produced during each session of the treatment can be controlled, which not only guarantees consistency across different sessions, but also makes it possible to focus on a single phenomenon, which is difficult even for a trained professional to perform, and deliver the stimuli according to the treatment plan. In this article, we provide a comprehensive review of research on recent technology-facilitated diagnosis and treat of children and adults with ASD. Different from existing reviews on this topic, which predominantly concern clinical issues, we focus on the engineering perspective of autism studies. All technology facilitated systems used for autism studies can be modeled as human machine interactive systems where one or more participants would constitute as the human component, and a computer-based or a robotic-based system would be the machine component. Based on this model, we organize our review with the following questions: (1) What are presented to the participants in the studies and how are the content and delivery methods enabled by technologies? (2) How are the reactions/inputs collected from the participants in response to the stimuli in the studies? (3) Are the experimental procedure and programs presented to participants dynamically adjustable based on the responses from the participants, and if so, how? and (4) How are the programs assessed? Full article

(This article belongs to the Special Issue Smart Healthcare)

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16 pages, 3982 KiB

Open AccessReview

Research Progress of Related Technologies of Electric-Pneumatic Pressure Proportional Valves

by Fangwei Ning^1,†, Yan Shi^1,2,*,†, Maolin Cai¹, Yixuan Wang¹ and Weiqing Xu^1,*

¹ School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China

² The State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 10058, China

^† These authors contribute equally to this paper.

Appl. Sci. 2017, 7(10), 1074; https://doi.org/10.3390/app7101074 - 17 Oct 2017

Cited by 20 | Viewed by 11500

Abstract

Because of its cleanness, safety, explosion proof, and other characteristics, pneumatic technologies have been applied in numerous industrial automation fields. As a key controlling element of a pneumatic system, electric-pneumatic pressure proportional valves have attracted the attention of many scholars in recent years. [...] Read more.

Because of its cleanness, safety, explosion proof, and other characteristics, pneumatic technologies have been applied in numerous industrial automation fields. As a key controlling element of a pneumatic system, electric-pneumatic pressure proportional valves have attracted the attention of many scholars in recent years. In this paper, in order to illustrate the research status and the development trend of electric-pneumatic pressure proportional valves, firstly, several related technologies will be introduced, for example, simulation methods and experimental modes. In addition, controlling methods, structural styles, and feedback forms are also compared in several types of pressure proportional valves. Moreover, the controlling strategy, as a significant relevant factor affecting the efficiency of valves, will be discussed in this paper. At the end, the conclusion and worksof electric-pneumatic pressure proportional valves in the future will bediscussed to achieve the electrical integration. Full article

(This article belongs to the Special Issue Power Transmission and Control in Power and Vehicle Machineries)

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10 pages, 2321 KiB

Open AccessPerspective

A New Line for Laser-Driven Light Ions Acceleration and Related TNSA Studies

by Leonida Antonio Gizzi^1,2,*, Dario Giove³, Carmen Altana^4,5, Fernando Brandi^1,6, Pablo Cirrone⁵, Gabriele Cristoforetti¹, Alberto Fazzi⁷, Paolo Ferrara¹, Lorenzo Fulgentini¹, Petra Koester¹, Luca Labate^1,2, Gaetano Lanzalone^5,8, Pasquale Londrillo⁹, David Mascali⁵, Annamaria Muoio⁵

, Daniele Palla^1,2,10, Francesco Schillaci^5,11, Stefano Sinigardi⁹, Salvatore Tudisco⁵

and Giorgio Turchetti⁹

¹ Intense Laser Irradiation Laboratory (ILIL), Istituto Nazionale di Ottica (INO), Consiglio Nazionale delle Ricerche (CNR), Via G. Moruzzi 1, 56124 Pisa, Italy

² Istituto Nazionale di Fisica Nucleare (INFN) Sezione di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy

³ Istituto Nazionale di Fisica Nucleare, Laboratorio Acceleratori e Superconduttività Applicata (INFN-LASA), Via Fratelli Cervi 201, 20090 Segrate, Italy

⁴ Dipartimento di Fisica e Astronomia, Università degli Studi di Catania, 95123 Catania, Italy

⁵ Laboratori Nazionali del Sud, INFN, Via S. Sofia, 95125 Catania, Italy

⁶ Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy

⁷ Dipartimento di Energia, Politecnico di Milano and INFN, Sezione di Milano, via Lambruschini 4, 20156 Milano, Italy

⁸ Università degli Studi di Enna Kore, Via delle Olimpiadi, 94100 Enna, Italy

⁹ Dipartimento di Fisica e Astronomia, Università di Bologna and INFN, Sez. di Bologna, 40126 Bologna, Italy

¹⁰ Dipartimento di Fisica, Università di Pisa, 56124 Pisa, Italy

¹¹ Institute of Physics Czech Academy of Science, ELI-Beamlines, Za Radnicí 835, 252 41 Dolní Břežany, Czech Republic

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Appl. Sci. 2017, 7(10), 984; https://doi.org/10.3390/app7100984 - 25 Sep 2017

Cited by 21 | Viewed by 5592

Abstract

In this paper, we present the status of the line for laser-driven light ions acceleration (L3IA) currently under implementation at the Intense Laser Irradiation Laboratory (ILIL), and we provide an overview of the pilot experimental activity on laser-driven ion acceleration carried out in [...] Read more.

In this paper, we present the status of the line for laser-driven light ions acceleration (L3IA) currently under implementation at the Intense Laser Irradiation Laboratory (ILIL), and we provide an overview of the pilot experimental activity on laser-driven ion acceleration carried out in support of the design of the line. A description of the main components is given, including the laser, the beam transport line, the interaction chamber, and the diagnostics. A review of the main results obtained so far during the pilot experimental activity is also reported, including details of the laser-plasma interaction and ion beam characterization. A brief description of the preliminary results of a dedicated numerical modeling is also provided. Full article

(This article belongs to the Special Issue Laser-Driven Particle Acceleration)

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14 pages, 6693 KiB

Open AccessPerspective

Privacy-Preserving Aggregation and Authentication of Multi-Source Smart Meters in a Smart Grid System

by Dongyoung Koo¹

, Youngjoo Shin^2,* and Junbeom Hur^3,*

¹ Department of Electronics and Information Engineering, Hansung University, 116 Samseongyo-ro 16-gil, Seongbuk-gu, Seoul 02876, Korea

² School of Computer & Information Engineering, Kwangwoon University, 20 Kwangwoon-ro, Nowon-gu, Seoul 01897, Korea

³ Department of Computer Science and Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea

Appl. Sci. 2017, 7(10), 1007; https://doi.org/10.3390/app7101007 - 29 Sep 2017

Cited by 14 | Viewed by 6155

Abstract

The smart grid is a promising electrical grid paradigm for enhancing flexibility and reliability in power transmission through two-way communications among grid entities. In the smart grid system, the privacy of usage information measured by individual smart meters has gained significant attention, owing [...] Read more.

The smart grid is a promising electrical grid paradigm for enhancing flexibility and reliability in power transmission through two-way communications among grid entities. In the smart grid system, the privacy of usage information measured by individual smart meters has gained significant attention, owing to the possibility of personal information inference. Moreover, efficient and reliable power provisioning can be seriously impeded through illicit manipulations of aggregated data under the influence of malicious adversaries. Due to such potential risks, it becomes an important requirement for the smart grid to preserve privacy of metering data by secure aggregation and to authenticate the aggregated result in an efficient manner within large scale environments. From this perspective, this paper investigates the current status of security and privacy in smart grid systems and representative state-of-the-art studies in secure aggregation and authentication of metering data for future directions of a smart grid. Full article

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12 pages, 2194 KiB

Open AccessFeature PaperPerspective

Advances in High-Power, Ultrashort Pulse DPSSL Technologies at HiLASE

by Martin Smrž^*, Ondřej Novák, Jiří Mužík, Hana Turčičová, Michal Chyla, Siva Sankar Nagisetty, Michal Vyvlečka, Lukáš Roškot, Taisuke Miura, Jitka Černohorská, Pawel Sikocinski, Liyuan Chen, Jaroslav Huynh, Patricie Severová, Alina Pranovich, Akira Endo and Tomáš Mocek

HiLASE Centre, Institute of Physics AS CR, v.v.i., Za radnicí 828, Dolní Břažany 252 41, Czech Republic

Appl. Sci. 2017, 7(10), 1016; https://doi.org/10.3390/app7101016 - 1 Oct 2017

Cited by 59 | Viewed by 7149

Abstract

The development of kW-class diode-pumped picosecond laser sources emitting at various wavelengths started at the HiLASE Center four years ago. A 500-W Perla C thin-disk laser with a diffraction limited beam and repetition rate of 50–100 kHz, a frequency conversion to mid-infrared (mid-IR), [...] Read more.

The development of kW-class diode-pumped picosecond laser sources emitting at various wavelengths started at the HiLASE Center four years ago. A 500-W Perla C thin-disk laser with a diffraction limited beam and repetition rate of 50–100 kHz, a frequency conversion to mid-infrared (mid-IR), and second to fifth harmonic frequencies was demonstrated. We present an updated review on the progress in the development of compact picosecond and femtosecond high average power radiation sources covering the ultraviolet (UV) to mid-IR spectral range at the HiLASE Center. We also report on thin-disk manufacturing by atomic diffusion bonding, which is a crucial technology for future high-power laser development. Full article

(This article belongs to the Section Optics and Lasers)

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8 pages, 1543 KiB

Open AccessPerspective

Membrane Engineering for Sustainable Development: A Perspective

by Aamer Ali¹, Enrico Drioli^1,2,3

and Francesca Macedonio^1,2,*

¹ National Research Council—Institute on Membrane Technology (ITM–CNR), Via Pietro BUCCI, c/oUniversity of Calabria, cubo 17C, Rende 87036, Italy

² Department of Environmental and Chemical Engineering, University of Calabria, Rende 87036, Italy

³ Hanyang University, WCU Energy Engineering Department, Seoul 133‐791, South Korea

Appl. Sci. 2017, 7(10), 1026; https://doi.org/10.3390/app7101026 - 6 Oct 2017

Cited by 16 | Viewed by 5410

Abstract

Membrane engineering can offer an important contribution in realizing sustainable industrial development. It provides opportunities to redesign the conventional process of engineering in the logic of Process Intensification. Relatively new and less exploited membrane operations offer innovative solutions to the scarcity of raw [...] Read more.

Membrane engineering can offer an important contribution in realizing sustainable industrial development. It provides opportunities to redesign the conventional process of engineering in the logic of Process Intensification. Relatively new and less exploited membrane operations offer innovative solutions to the scarcity of raw materials, freshwater and energy. Here, we identify the most interesting aspects of membrane engineering in some strategic industrial sectors. Several cases of either successful or innovative membrane technologies are discussed. Full article

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

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5 pages, 613 KiB

Open AccessPerspective

Towards an Alternate Evaluation of Moisture-Induced Damage of Bituminous Materials

by Aboelkasim Diab¹

, Zhanping You^2,*, Xu Yang³ and Mohd Rosli Mohd Hasan⁴

¹ Department of Civil Engineering, Aswan University, Aswan 81542, Egypt

² Department of Civil and Environmental Engineering, Michigan Technological University, Houghton, MI 49931, USA

³ Department of Civil Engineering, Monash University, Clayton, VIC 3800, Australia

⁴ School of Civil Engineering, Universiti Sains Malaysia, Engineering Campus, Nibong Tebal Penang 14300, Malaysia

Appl. Sci. 2017, 7(10), 1049; https://doi.org/10.3390/app7101049 - 13 Oct 2017

Cited by 8 | Viewed by 3767

Abstract

Moisture-induced damage is widely known to cause multiple distresses that affect the durability of constructed pavements and eventually lead to the costly maintenance of pavement structures. The reliability and practicality of the assessment protocol to evaluate moisture susceptibility of flexible pavements presents a [...] Read more.

Moisture-induced damage is widely known to cause multiple distresses that affect the durability of constructed pavements and eventually lead to the costly maintenance of pavement structures. The reliability and practicality of the assessment protocol to evaluate moisture susceptibility of flexible pavements presents a dilemma within the asphalt community that arises from the complexity and interrelation of moisture mechanisms in the asphalt–aggregate system. Researchers worldwide are continuously trying to develop suitable evaluation methods to simulate the combined destructive field-induced effects of moisture in the laboratory to help practitioners identify and alleviate this complex problem. The main objective of this article is to provide insights and highlight the challenges and opportunities of this important topic in order to extend and share knowledge towards finding a realistic assessment protocol of moisture damage in the laboratory. Two scenarios are proposed in this article: (1) a damage rate concept that accounts for the change of mechanical property (e.g., indirect tensile strength) with respect to the conditioning time, and (2) the establishment of a database using a surface free energy concept to help stakeholders select appropriate asphalt–aggregate combinations without the need to run additional moisture susceptibility tests. Full article

(This article belongs to the Special Issue Advanced Asphalt Materials and Paving Technologies)

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