Applied Sciences

11 pages, 10285 KiB

Open AccessArticle

Needle Segmentation in Volumetric Optical Coherence Tomography Images for Ophthalmic Microsurgery

by Mingchuan Zhou¹, Hessam Roodaki¹, Abouzar Eslami², Guang Chen^1,*, Kai Huang^3,*, Mathias Maier⁴, Chris P. Lohmann⁴, Alois Knoll¹ and Mohammad Ali Nasseri⁴

¹ Institut für Informatik, Technische Universität München, 85748 München, Germany

² Carl Zeiss Meditec AG., 81379 München, Germany

³ School of Data and Computer Science, Sun Yat-Sen University, Guangzhou 510006, China

⁴ Augenklinik und Poliklinik, Klinikum rechts der Isar der Technische Universit München, 81675 München, Germany

Appl. Sci. 2017, 7(8), 748; https://doi.org/10.3390/app7080748 - 25 Jul 2017

Cited by 25 | Viewed by 6773

Abstract

Needle segmentation is a fundamental step for needle reconstruction and image-guided surgery. Although there has been success stories in needle segmentation for non-microsurgeries, the methods cannot be directly extended to ophthalmic surgery due to the challenges bounded to required spatial resolution. As the [...] Read more.

Needle segmentation is a fundamental step for needle reconstruction and image-guided surgery. Although there has been success stories in needle segmentation for non-microsurgeries, the methods cannot be directly extended to ophthalmic surgery due to the challenges bounded to required spatial resolution. As the ophthalmic surgery is performed by finer and smaller surgical instruments in micro-structural anatomies, specifically in retinal domains, difficulties are raised for delicate operation and sensitive perception. To address these challenges, in this paper we investigate needle segmentation in ophthalmic operation on 60 Optical Coherence Tomography (OCT) cubes captured during needle injection surgeries on ex-vivo pig eyes. Furthermore, we developed two different approaches, a conventional method based on morphological features (MF) and a specifically designed full convolution neural networks (FCN) method, moreover, we evaluate them on the benchmark for needle segmentation in the volumetric OCT images. The experimental results show that FCN method has a better segmentation performance based on four evaluation metrics while MF method has a short inference time, which provides valuable reference for future works. Full article

(This article belongs to the Special Issue Development and Application of Optical Coherence Tomography (OCT))

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14 pages, 1789 KiB

Open AccessArticle

Prediction of Ultimate Strain and Strength of FRP-Confined Concrete Cylinders Using Soft Computing Methods

by Iman Mansouri¹, Ozgur Kisi², Pedram Sadeghian³, Chang-Hwan Lee⁴ and Jong Wan Hu^5,6,*

¹ Department of Civil Engineering, Birjand University of Technology, Birjand 97175-569, Iran

² School of Natural Sciences and Engineering, Ilia State University, Tbilisi 0162, Georgia

³ Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington Street, Halifax, NS B3H 4R2, Canada

⁴ Research Institute of Structural Engineering & System, DongYang Structural Engineers Co., Ltd., Seoul 05836, Korea

⁵ Department of Civil and Environmental Engineering, Incheon National University, Incheon 22012, Korea

⁶ Incheon Disaster Prevention Research Center, Incheon National University, Incheon 22012, Korea

Appl. Sci. 2017, 7(8), 751; https://doi.org/10.3390/app7080751 - 25 Jul 2017

Cited by 34 | Viewed by 5887

Abstract

This paper investigates the effectiveness of four different soft computing methods, namely radial basis neural network (RBNN), adaptive neuro fuzzy inference system (ANFIS) with subtractive clustering (ANFIS-SC), ANFIS with fuzzy c-means clustering (ANFIS-FCM) and M5 model tree (M5Tree), for predicting the ultimate strength [...] Read more.

This paper investigates the effectiveness of four different soft computing methods, namely radial basis neural network (RBNN), adaptive neuro fuzzy inference system (ANFIS) with subtractive clustering (ANFIS-SC), ANFIS with fuzzy c-means clustering (ANFIS-FCM) and M5 model tree (M5Tree), for predicting the ultimate strength and strain of concrete cylinders confined with fiber-reinforced polymer (FRP) sheets. The models were compared according to the root mean square error (RMSE), mean absolute relative error (MARE) and determination coefficient (R²) criteria. Similar accuracy was obtained by RBNN and ANFIS-FCM, and they provided better estimates in modeling ultimate strength of confined concrete. The ANFIS-SC, however, performed slightly better than the RBNN and ANFIS-FCM in estimating ultimate strain of confined concrete, and M5Tree provided the worst strength and strain estimates. Finally, the effects of strain ratio and the confinement stiffness ratio on strength and strain were investigated, and the confinement stiffness ratio was shown to be more effective. Full article

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

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22 pages, 18795 KiB

Open AccessFeature PaperArticle

Automated Diatom Classification (Part A): Handcrafted Feature Approaches

by Gloria Bueno^1,*

, Oscar Deniz¹

, Anibal Pedraza¹

, Jesús Ruiz-Santaquiteria¹, Jesús Salido¹

, Gabriel Cristóbal²

, María Borrego-Ramos³

and Saúl Blanco³

¹ VISILAB-University of Castilla-La Mancha, Av. Camilo José Cela s/n, 13071 Ciudad Real, Spain

² Institute of Optics, Spanish National Research Council (CSIC), Serrano 121, 28006 Madrid, Spain

³ The Institute of the Environment, University of Leon, E-24071 León, Spain

Appl. Sci. 2017, 7(8), 753; https://doi.org/10.3390/app7080753 - 25 Jul 2017

Cited by 55 | Viewed by 13378

Abstract

This paper deals with automatic taxa identification based on machine learning methods. The aim is therefore to automatically classify diatoms, in terms of pattern recognition terminology. Diatoms are a kind of algae microorganism with high biodiversity at the species level, which are useful [...] Read more.

This paper deals with automatic taxa identification based on machine learning methods. The aim is therefore to automatically classify diatoms, in terms of pattern recognition terminology. Diatoms are a kind of algae microorganism with high biodiversity at the species level, which are useful for water quality assessment. The most relevant features for diatom description and classification have been selected using an extensive dataset of 80 taxa with a minimum of 100 samples/taxon augmented to 300 samples/taxon. In addition to published morphological, statistical and textural descriptors, a new textural descriptor, Local Binary Patterns (LBP), to characterize the diatom’s valves, and a log Gabor implementation not tested before for this purpose are introduced in this paper. Results show an overall accuracy of 98.11% using bagging decision trees and combinations of descriptors. Finally, some phycological features of diatoms that are still difficult to integrate in computer systems are discussed for future work. Full article

(This article belongs to the Special Issue Automated Analysis and Identification of Phytoplankton Images)

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15 pages, 2400 KiB

Open AccessArticle

Modified Chaos Particle Swarm Optimization-Based Optimized Operation Model for Stand-Alone CCHP Microgrid

by Fei Wang^1,2,*

, Lidong Zhou¹, Bo Wang³, Zheng Wang³, Miadreza Shafie-khah⁴

and João P. S. Catalão^4,5,6,*

¹ State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Baoding 071003, China

² Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA

³ State Key Laboratory of Operation and Control of Renewable Energy & Storage Systems, China Electric Power Research Institute, Beijing 100192, China

⁴ C-MAST, University of Beira Interior, 6201-001 Covilhã, Portugal

⁵ INESC TEC and the Faculty of Engineering of the University of Porto, 4200-465 Porto, Portugal

⁶ INESC-ID, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal

Appl. Sci. 2017, 7(8), 754; https://doi.org/10.3390/app7080754 - 25 Jul 2017

Cited by 26 | Viewed by 5650

Abstract

The optimized dispatch of different distributed generations (DGs) in stand-alone microgrid (MG) is of great significance to the operation’s reliability and economy, especially for energy crisis and environmental pollution. Based on controllable load (CL) and combined cooling-heating-power (CCHP) model of micro-gas turbine (MT), [...] Read more.

The optimized dispatch of different distributed generations (DGs) in stand-alone microgrid (MG) is of great significance to the operation’s reliability and economy, especially for energy crisis and environmental pollution. Based on controllable load (CL) and combined cooling-heating-power (CCHP) model of micro-gas turbine (MT), a multi-objective optimization model with relevant constraints to optimize the generation cost, load cut compensation and environmental benefit is proposed in this paper. The MG studied in this paper consists of photovoltaic (PV), wind turbine (WT), fuel cell (FC), diesel engine (DE), MT and energy storage (ES). Four typical scenarios were designed according to different day types (work day or weekend) and weather conditions (sunny or rainy) in view of the uncertainty of renewable energy in variable situations and load fluctuation. A modified dispatch strategy for CCHP is presented to further improve the operation economy without reducing the consumers’ comfort feeling. Chaotic optimization and elite retention strategy are introduced into basic particle swarm optimization (PSO) to propose modified chaos particle swarm optimization (MCPSO) whose search capability and convergence speed are improved greatly. Simulation results validate the correctness of the proposed model and the effectiveness of MCPSO algorithm in the optimized operation application of stand-alone MG. Full article

(This article belongs to the Special Issue Smart Home and Energy Management Systems)

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16 pages, 5204 KiB

Open AccessArticle

Development of a Magnetostrictive FeNi Coated Surface Acoustic Wave Current Sensor

by Jie Tong¹, Yana Jia^2,3, Wen Wang^2,*, Yang Wang¹, Shiyue Wang¹, Xinlu Liu² and Yuqing Lei¹

¹ China Electric Power Research Institute of State Grid, Beijing 100192, China

² State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, No. 21, Beisihuan West Road, Beijing 100190, China

³ School of Electronic. Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China

Appl. Sci. 2017, 7(8), 755; https://doi.org/10.3390/app7080755 - 25 Jul 2017

Cited by 17 | Viewed by 6260

Abstract

A magnetostrictive FeNi-coated surface acoustic wave (SAW)-based current sensor was proposed in this work. The weak remanence and hysteresis effect of the FeNi itself contributes to suppress the asymmetry in sensor response at increasing and decreasing current. The sensor response was simulated by [...] Read more.

A magnetostrictive FeNi-coated surface acoustic wave (SAW)-based current sensor was proposed in this work. The weak remanence and hysteresis effect of the FeNi itself contributes to suppress the asymmetry in sensor response at increasing and decreasing current. The sensor response was simulated by solving the coupled electromechanical field equation in layered structure considering the magnetostrictive effect and an approach of effective dielectric constant. The effects from the aspect ratio and thickness of the FeNi film on sensor response were analyzed to determine the optimal design parameters. Differential oscillation structure was used to form the sensor, in which, the FeNi thin film was deposited along the SAW propagation of the sensor chip by using RF magnetron sputtering. The magnetostrictive effect of the FeNi coating induced by the magnetic loading generates the perturbation in SAW velocity, and corresponding oscillation frequency. High sensitivity of 10.7 KHz/A, good linearity and repeatability, lower hysteresis error of 0.97% were obtained from the developed prototype 150 MHz SAW FeNi coated current sensor. Full article

(This article belongs to the Section Acoustics and Vibrations)

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8 pages, 374 KiB

Open AccessProject Report

Optimization of a Culture Medium Using the Taguchi Approach for the Production of Microorganisms Active in Odorous Compound Removal

by Krzysztof Makowski^1,2, Katarzyna Matusiak³, Sebastian Borowski^3,*, Jakub Bielnicki¹, Alicja Tarazewicz^1,†, Marta Maroszyńska¹, Martyna Leszczewicz¹, Szymon Powałowski⁴ and Beata Gutarowska³

¹ Bionanopark, Laboratory of Industrial Biotechnology Ltd. Dubois 114/116, 93-465 Łódź, Poland

² Institute of Materials Science and Engineering, Lodz University of Technology, Stefanowskiego 1/15, 90-924 Łódź, Poland

³ Institute of Fermentation Technology and Microbiology, Lodz University of Technology, Wólczańska 171/173, 90-924 Łódź, Poland

⁴ JHJ Sp. z o.o., 63-308 Gizałki, Poland

^† Author has passed away.

Appl. Sci. 2017, 7(8), 756; https://doi.org/10.3390/app7080756 - 25 Jul 2017

Cited by 21 | Viewed by 5469

Abstract

The aim of this work was to develop the composition of a medium for the cultivation of six microbial strains forming a deodorizing consortium: Pseudomonas fluorescens, Enterococcus faecium, Bacillus subtilis, Bacillus megaterium, Leuconostoc mesenteroides and Lactobacillus plantarum. The [...] Read more.

The aim of this work was to develop the composition of a medium for the cultivation of six microbial strains forming a deodorizing consortium: Pseudomonas fluorescens, Enterococcus faecium, Bacillus subtilis, Bacillus megaterium, Leuconostoc mesenteroides and Lactobacillus plantarum. The study focused on the optimization of a highly efficient culture medium composed of readily available components of plant origin to maximize microbial biomass yields, and to create a less expensive alternative to the commercial Tryptic Soy Broth medium (TSB). After preliminary efficiency screening of all tested media components, we selected four substrates for further optimization—soy protein concentrate (SPC), glucose or sucrose, and phosphate salts. The final concentrations of all components were fine-tuned using the Taguchi design for experiments according to an L₉ array. Taguchi optimization led to formulation of a culture medium, which was approximately 5 times cheaper than TSB (depending on the components used). Consequently, microbial biomass yields were improved by up to 15-fold (1564%), depending on the strain. The results obtained in the laboratory experiments were then confirmed in pilot- (42 L) and industrial- (300 L) scale fermentation. Our results show that this method of using a parallel culture microbioreactor with the Taguchi approach can be recommended for optimization of culture media based on substrates of plant origin. Full article

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16 pages, 2861 KiB

Open AccessArticle

A Real Model of a Micro-Grid to Improve Network Stability

by Petr Marcon^1,2,*

, Zoltan Szabo^1,2, Ivo Vesely^2,3, Frantisek Zezulka^2,3, Ondrej Sajdl², Zdenek Roubal^1,2 and Premysl Dohnal¹

¹ Department of Theoretical and Experimental Electrical Engineering, FEEC, Brno University of Technology, Technicka 12, 61600 Brno, Czech Republic

² Centre for Research and utilization of Renewable Energy, FEEC, Brno University of Technology, Technicka 12, 61600 Brno, Czech Republic

³ Department of Control and Instrumentation, FEEC, Brno University of Technology, Technicka 12, 61600 Brno, Czech Republic

Appl. Sci. 2017, 7(8), 757; https://doi.org/10.3390/app7080757 - 26 Jul 2017

Cited by 9 | Viewed by 5496

Abstract

This paper discusses the smart energy model of a smart grid using a significant share of renewable energy sources combined with intelligent control that processes information from a smart metering subsystem. An algorithm to manage the microgrid via the demand-response strategy is proposed, [...] Read more.

This paper discusses the smart energy model of a smart grid using a significant share of renewable energy sources combined with intelligent control that processes information from a smart metering subsystem. An algorithm to manage the microgrid via the demand-response strategy is proposed, accentuating the requirement that the total volume of energy produced from renewable sources is consumed. Thus, the system utilizes the maximum of renewable sources to reduce CO₂ emissions. Another major benefit provided by the algorithm lies in applying the current weather forecast to predict the amount of energy in the grid; electricity can then be transferred between the local and the main backup batteries within the grid, and this option enables the control elements to prepare for a condition yet to occur. Individual parts of the grid are described in this research report together with the results provided by the relevant algorithm. Full article

(This article belongs to the Special Issue Smart Home and Energy Management Systems)

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19 pages, 653 KiB

Open AccessArticle

Performance Analysis and Design Strategy for a Second-Order, Fixed-Gain, Position-Velocity-Measured (α-β-η-θ) Tracking Filter

by Kenshi Saho^1,*

and Masao Masugi²

¹ Department of Intelligent Systems Design Engineering, Toyama Prefectural University, Imizu 939-0398, Japan

² Department of Electronic and Computer Engineering, Ritsumeikan University, Kusatsu 525-8577, Japan

Appl. Sci. 2017, 7(8), 758; https://doi.org/10.3390/app7080758 - 26 Jul 2017

Cited by 7 | Viewed by 4818

Abstract

We present a strategy for designing an

α

-

β

-

η

-

θ

filter, a fixed-gain moving-object tracking filter using position and velocity measurements. First, performance indices and stability conditions for the filter are analytically derived. Then, an optimal gain design strategy [...] Read more.

We present a strategy for designing an

α

-

β

-

η

-

θ

filter, a fixed-gain moving-object tracking filter using position and velocity measurements. First, performance indices and stability conditions for the filter are analytically derived. Then, an optimal gain design strategy using these results is proposed and its relationship to the position-velocity-measured (PVM) Kalman filter is shown. Numerical analyses demonstrate the effectiveness of the proposed strategy, as well as a performance improvement over the traditional position-only-measured

α

-

β

filter. Moreover, we apply an

α

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β

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η

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θ

filter designed using this strategy to ultra-wideband Doppler radar tracking in numerical simulations. We verify that the proposed strategy can easily design the gains for an

α

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β

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η

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θ

filter based on the performance of the ultra-wideband Doppler radar and a rough approximation of the target’s acceleration. Moreover, its effectiveness in predicting the steady state performance in designing the position-velocity-measured Kalman filter is also demonstrated. Full article

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

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20 pages, 2585 KiB

Open AccessArticle

A Novel Hybrid Approach to Deal with DVL Malfunctions for Underwater Integrated Navigation Systems

by Yixian Zhu^1,2, Xianghong Cheng^1,2,*

, Jie Hu^1,2, Ling Zhou^1,2,3 and Jinbo Fu¹

¹ School of Instrument Science and Engineering, Southeast University, Nanjing 210096, China

² Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology, Ministry of Education, Southeast University, Nanjing 210096, China

³ Department of Physics and Electronic Engineering, Yuncheng University, Yuncheng 044000, China

Appl. Sci. 2017, 7(8), 759; https://doi.org/10.3390/app7080759 - 26 Jul 2017

Cited by 19 | Viewed by 4697

Abstract

As a common device for underwater integrated navigation systems, Doppler velocity log (DVL) has the risk of malfunction. To improve the reliability of navigation systems, a hybrid approach is presented to forecast the measurements of the DVL while it malfunctions. The approach employs [...] Read more.

As a common device for underwater integrated navigation systems, Doppler velocity log (DVL) has the risk of malfunction. To improve the reliability of navigation systems, a hybrid approach is presented to forecast the measurements of the DVL while it malfunctions. The approach employs partial least squares regression (PLSR) coupled with support vector regression (SVR) to build a hybrid predictor. As the current and past calculating velocities of strapdown inertial navigation system (SINS) are taken as the predictor’s inputs, PLSR is applied to cope with the situation where there exists intense relativity among independent variables. Since PLSR is a linear regression, SVR is used to predict the residual components of the PLSR prediction to improve the accuracy. When the DVL works well, the hybrid predictor is trained online as a backup, whereas during malfunctions, the predictor offers the estimation of the DVL measurements for information fusion. The performance of the proposed approach is verified with simulations based on SINS/DVL/MCP/pressure sensor (PS) integrated navigation system. The comparison results indicate that the PLSR-SVR hybrid predictor can correctly provide the estimated DVL measurements and effectively extend the tolerance time on DVL malfunctions, thereby improving the navigation accuracy and reliability. Full article

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18 pages, 5479 KiB

Open AccessArticle

The Static Frictional Behaviors of Rubber for Pipe-Laying Operation

by Yong-Jie Zhou¹, De-Guo Wang^1,2, Yan-Bao Guo^1,2,* and Shu-Hai Liu^1,2

¹ College of Mechanical and Transportation Engineering, China University of Petroleum, Beijing 102249, China

² Laboratory of Tribology and Surface Engineering, China University of Petroleum, Beijing 102249, China

Appl. Sci. 2017, 7(8), 760; https://doi.org/10.3390/app7080760 - 26 Jul 2017

Cited by 5 | Viewed by 5930

Abstract

Experimental research is carried out to reveal the static frictional behaviors of rubber pipe contact systems. This research is motivated by deep water pipe-laying operations where rubber blocks are used to clamp the pipe to supply sufficient static friction. Within this context, a [...] Read more.

Experimental research is carried out to reveal the static frictional behaviors of rubber pipe contact systems. This research is motivated by deep water pipe-laying operations where rubber blocks are used to clamp the pipe to supply sufficient static friction. Within this context, a friction testing instrument has been designed to mimic a situation of the beginning of the pipe-laying installation. Using this instrument, the maximum static friction forces (F) of a rubber pipe contact system are tested. The results show that the ultimate values of the static frictions fluctuate due to the increasing rate of the tangential load (F_T). The evolution of contact between rubber and polymethyl methacrylate (PMMA) pipe is observed to identify the formation and propagation of the folds within the apparent contact area. In addition, it is confirmed that the evolution of contact is influenced by the folds and creep of the rubber surface. The creep deformation takes primary effect in accelerating the separation of the interfaces of contact during relative high normal loads (20, 30, 40 N) and low increasing rate of F_T; whereas for all of the testing normal loads (10–40 N), the propagation of the folds release the energy which is stored in the interface of rubber when the increasing rate of F_T is high. Therefore, the fluctuation of the maximum static friction of the contact system can be regarded as a consequence of interaction of the creep and folds. Furthermore, the instability of the coefficient of static friction in this test has been examined, and it indicated that the creep and folds could affect the static friction distinctly within a certain range of a normal load. This research is beneficial for arranging appropriate normal loads and laying speeds to avoid pipes slipping during a pipe-laying operation. Full article

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12 pages, 2021 KiB

Open AccessFeature PaperReview

Non-Local Effects in Brillouin Optical Time-Domain Analysis Sensors

by Haritz Iribas

, Javier Urricelqui, Juan José Mompó, Jon Mariñelarena and Alayn Loayssa^*

Institute of Smart Cities, Universidad Pública de Navarra, Campus Arrosadia s/n, 31006 Iruñea, Spain

Appl. Sci. 2017, 7(8), 761; https://doi.org/10.3390/app7080761 - 27 Jul 2017

Cited by 13 | Viewed by 5676

Abstract

Brillouin optical time-domain analysis (BOTDA) sensors have great potential to provide distributed measurements of temperature and strain over large structures with high spatial resolution and measurement precision. However, their performance ultimately depends on the amount of probe and pump pulse power that can [...] Read more.

Brillouin optical time-domain analysis (BOTDA) sensors have great potential to provide distributed measurements of temperature and strain over large structures with high spatial resolution and measurement precision. However, their performance ultimately depends on the amount of probe and pump pulse power that can be injected into the sensing fiber, which determines the signal-to-noise ratio of the detected measurement signal. The probe wave power is constrained by the generation of noise induced by spontaneous Brillouin scattering and at lower power by the so-called non-local effects. In this work, we focus on the latter. We review the physical origins of non-local effects and analyze the performance impairments that they bring. In addition, we discuss the different methods that have been proposed to counteract these effects comparing their relative merits and ultimate performance. Particularly, we focus on a technique that we have devised to compensate non-local effects which is based on introducing an optical frequency modulation or dithering to the probe wave. This method is shown to provide a comprehensive solution to most of the impairments associated with non-local effects and also to enable some side benefits, such as amplification of the pump pulses to compensate the attenuation of the fiber. Full article

(This article belongs to the Special Issue Distributed Optical Fiber Sensors)

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16 pages, 3932 KiB

Open AccessArticle

A Tuning Method for Diatom Segmentation Techniques

by Oswaldo Rojas Camacho^1,*, Manuel Guillermo Forero²

and José Manuel Menéndez³

¹ Departamento de Ingeniería de Sistemas e Industrial, Universidad Nacional de Colombia, Bogotá 111321, Colombia

² Semillero Lún, Group D+TEC, Facultad de Ingeniería, Universidad de Ibagué, Ibagué 730001, Colombia

³ Escuela Técnica Superior de Ingenieros de Telecomunicación, Universidad Politécnica de Madrid, 28040 Madrid, Spain

Appl. Sci. 2017, 7(8), 762; https://doi.org/10.3390/app7080762 - 27 Jul 2017

Cited by 12 | Viewed by 4822

Abstract

Phytoplankton such as diatoms or desmids are useful for monitoring water quality. Manual image analysis is impractical due to the huge diversity of this group of microalgae and its great morphological plasticity, hence the importance of automating the analysis procedure. High-resolution images of [...] Read more.

Phytoplankton such as diatoms or desmids are useful for monitoring water quality. Manual image analysis is impractical due to the huge diversity of this group of microalgae and its great morphological plasticity, hence the importance of automating the analysis procedure. High-resolution images of phytoplankton cells can now be acquired by digital microscopes, which facilitate automating the analysis and identification process of specimens. Therefore, new systems of image analysis are potentially advantageous compared to manual methods of counting for solution identification. Segmentation is an important step in the analysis of phytoplankton images. Many standard techniques like thresholding and edge detection are employed in the segmentation of diatoms and other phytoplankton, which are crucial organisms in microscopy images. However, in general, they require several parameters to be fixed beforehand by the user in order to get the best results. This process is usually done by comparing results and looking for the best parameters. To automatize this process, we propose an automatic tuning method to find the optimal parameters in an iterative procedure, called Parametric Segmentation Tuning (PST). This technique compares successive segmentation results, choosing the ones that gets the maximal similarity. In this paper, tuning is formulated as an optimization problem using a similarity function within the solution space. This space consists of the set of binary images that are generated by the segmentation technique to be tuned, where these binary images are seen as a function of the original images and the segmentation parameters. The PST technique was tested with two of the most popular techniques employed to segment phytoplankton images: the Canny edge detection and a binarisation method. The results of the thresholding technique were validated by comparing them to those of the Otsu method and the Canny method with a ground truth. They show that PST is effective to find the best parameters. Full article

(This article belongs to the Special Issue Automated Analysis and Identification of Phytoplankton Images)

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21 pages, 7878 KiB

Open AccessArticle

Evaluation of Mechanical Properties of Recycled Material for Utilization in Asphalt Mixtures

by Farzaneh Tahmoorian^1,*, Bijan Samali¹, Vivian W.Y. Tam^2,3 and John Yeaman⁴

¹ Centre for Infrastructure Engineering, Western Sydney University, Kingswood, NSW 2751, Australia

² School of Computing, Engineering, and Mathematics, Western Sydney University, Kingswood, NSW 2751, Australia

³ College of Civil Engineering, Shenzhen University, Shenzhen 518060, China

⁴ Faculty of Science, Health, Education and Engineering, University of Sunshine Coast, Sippy Downs, Queensland 4556, Australia

Appl. Sci. 2017, 7(8), 763; https://doi.org/10.3390/app7080763 - 27 Jul 2017

Cited by 31 | Viewed by 7214

Abstract

With an expanding world, the demand for extensive road networks is increasing. As natural resources become scarce, the necessity of finding alternative resources has led to the idea of applying recycled material to pavement construction including asphalt pavements. Amongst all asphalt components, aggregate [...] Read more.

With an expanding world, the demand for extensive road networks is increasing. As natural resources become scarce, the necessity of finding alternative resources has led to the idea of applying recycled material to pavement construction including asphalt pavements. Amongst all asphalt components, aggregate constitutes the largest part of asphalt mixtures. Therefore, the utilization of recycled material for aggregate will represent an important opportunity to save virgin material and divert material away from landfills. Because of the large amount of construction waste generation around the world, using recycled construction aggregate (RCA) in asphalt mixtures appears to be an effective utilization of RCA. However, as aggregate plays an important role in the final performance of the asphalt mixture, an understanding of their properties is essential in designing an asphalt mixture. Therefore, in this research, the properties of RCA have been evaluated through laboratory investigations. Based on the test results, it is required that combination of RCA with some other targeted waste materials be considered in asphalt mixture. This paper presents the results of an experimental study to evaluate the RCA properties as an alternative for virgin aggregate in asphalt mixture under different percentages and combination with other aggregates, such as reclaimed asphalt pavement (RAP) and basalt. Full article

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

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11 pages, 2116 KiB

Open AccessArticle

3D Model Identification Using Weighted Implicit Shape Representation and Panoramic View

by Xun Jin¹ 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(8), 764; https://doi.org/10.3390/app7080764 - 27 Jul 2017

Cited by 5 | Viewed by 4747

Abstract

In this paper, we propose a 3 dimensional (3D) model identification method based on weighted implicit shape representation (WISR) and panoramic view. The WISR is used for 3D shape normalization. The 3D shape normalization method normalizes a 3D model by scaling, translation, and [...] Read more.

In this paper, we propose a 3 dimensional (3D) model identification method based on weighted implicit shape representation (WISR) and panoramic view. The WISR is used for 3D shape normalization. The 3D shape normalization method normalizes a 3D model by scaling, translation, and rotation with respect to the scale factor, center, and principal axes. The major advantage of the WISR is reduction of the influences caused by shape deformation and partial removal. The well-known scale-invariant feature transform descriptors are extracted from the panoramic view of the 3D model for feature matching. The panoramic view is a range image obtained by projecting a 3D model to the surface of a cylinder which is parallel to a principal axis determined by the 3D shape normalization. Because of using only one range image, the proposed method can provide small size of features and fast matching speed. The precision of the identification is 92% with 1200 models that consist of 24 deformed versions of 50 classes. The average feature size and matching time are 4.1 KB and 1.9 s. Full article

(This article belongs to the Special Issue Swarm Robotics)

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39 pages, 2992 KiB

Open AccessFeature PaperReview

The Performance and Fouling Control of Submerged Hollow Fiber (HF) Systems: A Review

by Ebrahim Akhondi^1,2, Farhad Zamani^1,3, Keng Han Tng^4,5, Gregory Leslie^4,5, William B. Krantz^1,6

, Anthony G. Fane¹ and Jia Wei Chew^1,3,*

¹ Singapore Membrane Technology Center, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 639798, Singapore

² Young Researchers and Elite Club, Central Tehran Branch, Islamic Azad University, Tehran 1469669191, Iran

³ School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore

⁴ UNESCO Centre for Membrane Science and Technology, Sydney, NSW 2052, Australia

⁵ School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia

⁶ Department of Chemical & Biological Engineering, University of Colorado, Boulder, CO 80309-0424, USA

Appl. Sci. 2017, 7(8), 765; https://doi.org/10.3390/app7080765 - 28 Jul 2017

Cited by 57 | Viewed by 11664

Abstract

The submerged membrane filtration concept is well-established for low-pressure microfiltration (MF) and ultrafiltration (UF) applications in the water industry, and has become a mainstream technology for surface-water treatment, pretreatment prior to reverse osmosis (RO), and membrane bioreactors (MBRs). Compared to submerged flat sheet [...] Read more.

The submerged membrane filtration concept is well-established for low-pressure microfiltration (MF) and ultrafiltration (UF) applications in the water industry, and has become a mainstream technology for surface-water treatment, pretreatment prior to reverse osmosis (RO), and membrane bioreactors (MBRs). Compared to submerged flat sheet (FS) membranes, submerged hollow fiber (HF) membranes are more common due to their advantages of higher packing density, the ability to induce movement by mechanisms such as bubbling, and the feasibility of backwashing. In view of the importance of submerged HF processes, this review aims to provide a comprehensive landscape of the current state-of-the-art systems, to serve as a guide for further improvements in submerged HF membranes and their applications. The topics covered include recent developments in submerged hollow fiber membrane systems, the challenges and developments in fouling-control methods, and treatment protocols for membrane permeability recovery. The highlighted research opportunities include optimizing the various means to manipulate the hydrodynamics for fouling mitigation, developing online monitoring devices, and extending the submerged HF concept beyond filtration. Full article

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

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14 pages, 5327 KiB

Open AccessArticle

A Study on the Stall Detection of an Axial Compressor through Pressure Analysis

by Haoying Chen^1,†

, Fengyong Sun^2,†

, Haibo Zhang^2,* and Wei Luo^1,†

¹ Jiangsu Province Key Laboratory of Aerospace Power System, College of Energy and Power Engineering, Nanjing University of Aeronautics and Astronautics, No. 29 Yudao Street, Nanjing 210016, China

² AVIC Aero-engine Control System Institute, No. 792 Liangxi Road, Wuxi 214000, China

^† These authors contributed equally to this work.

Appl. Sci. 2017, 7(8), 766; https://doi.org/10.3390/app7080766 - 28 Jul 2017

Cited by 3 | Viewed by 5504

Abstract

In order to research the inherent working laws of compressors nearing stall state, a series of compressor experiments are conducted. With the help of fast Fourier transform, the amplitude–frequency characteristics of pressures at the compressor inlet, outlet and blade tip region outlet are [...] Read more.

In order to research the inherent working laws of compressors nearing stall state, a series of compressor experiments are conducted. With the help of fast Fourier transform, the amplitude–frequency characteristics of pressures at the compressor inlet, outlet and blade tip region outlet are analyzed. Meanwhile, devices imitating inlet distortion were applied in the compressor inlet distortion disturbance. The experimental results indicated that compressor blade tip region pressure showed a better performance than the compressor’s inlet and outlet pressures in regards to describing compressor characteristics. What’s more, compressor inlet distortion always disturbed the compressor pressure characteristics. Whether with inlet distortion or not, the pressure characteristics of pressure periodicity and amplitude frequency could always be maintained in compressor blade tip pressure. For the sake of compressor real-time stall detection application, a compressor stall detection algorithm is proposed to calculate the compressor pressure correlation coefficient. The algorithm also showed a good monotonicity in describing the relationship between the compressor surge margin and the pressure correlation coefficient. Full article

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17 pages, 658 KiB

Open AccessArticle

Chinese Medical Question Answer Matching Using End-to-End Character-Level Multi-Scale CNNs

by Sheng Zhang^*

, Xin Zhang, Hui Wang, Jiajun Cheng, Pei Li and Zhaoyun Ding

College of Information Systems and Management, National University of Defense Technology, Changsha 410073, China

Appl. Sci. 2017, 7(8), 767; https://doi.org/10.3390/app7080767 - 28 Jul 2017

Cited by 75 | Viewed by 12655

Abstract

This paper focuses mainly on the problem of Chinese medical question answer matching, which is arguably more challenging than open-domain question answer matching in English due to the combination of its domain-restricted nature and the language-specific features of Chinese. We present an end-to-end [...] Read more.

This paper focuses mainly on the problem of Chinese medical question answer matching, which is arguably more challenging than open-domain question answer matching in English due to the combination of its domain-restricted nature and the language-specific features of Chinese. We present an end-to-end character-level multi-scale convolutional neural framework in which character embeddings instead of word embeddings are used to avoid Chinese word segmentation in text preprocessing, and multi-scale convolutional neural networks (CNNs) are then introduced to extract contextual information from either question or answer sentences over different scales. The proposed framework can be trained with minimal human supervision and does not require any handcrafted features, rule-based patterns, or external resources. To validate our framework, we create a new text corpus, named cMedQA, by harvesting questions and answers from an online Chinese health and wellness community. The experimental results on the cMedQA dataset show that our framework significantly outperforms several strong baselines, and achieves an improvement of top-1 accuracy by up to 19%. Full article

(This article belongs to the Special Issue Smart Healthcare)

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3 pages, 157 KiB

Open AccessEditorial

Special Issue on Polarimetric SAR Techniques and Applications

by Carlos Lopez-Martinez^1,*

and Juan M. Lopez-Sanchez^2,*

¹ ERIN Department, Luxembourg Institute of Science and Technology (LIST), L-4422 Belval, Luxembourg

² DFISTS–IUII, University of Alicante, P.O. Box 99, 03080 Alicante, Spain

Appl. Sci. 2017, 7(8), 768; https://doi.org/10.3390/app7080768 - 28 Jul 2017

Cited by 2 | Viewed by 3650

Abstract

Synthetic Aperture Radar (SAR) polarimetry is an active and fruitful field of research in Earth observation. [...]
Full article

(This article belongs to the Special Issue Polarimetric SAR Techniques and Applications)

16 pages, 7149 KiB

Open AccessArticle

The Synchrosqueezing Algorithm Based on Generalized S-transform for High-Precision Time-Frequency Analysis

by Hui Chen^*

, Lingqi Lu, Dan Xu, Jiaxing Kang and Xuping Chen

Geomathematics Key Laboratory of Sichuan Province, Chengdu University of Technology, Chengdu 610059, China

Appl. Sci. 2017, 7(8), 769; https://doi.org/10.3390/app7080769 - 28 Jul 2017

Cited by 26 | Viewed by 6374

Abstract

In this paper, a new time-frequency analysis method—Synchrosqueezing Generalized S-transform (SSGST)—is proposed to meet the needs of high-resolution seismic signal processing and interpretation. The basic wavelet of the generalized S-transform (GST) in the paper is a modulated harmonic wave with four undetermined parameters [...] Read more.

In this paper, a new time-frequency analysis method—Synchrosqueezing Generalized S-transform (SSGST)—is proposed to meet the needs of high-resolution seismic signal processing and interpretation. The basic wavelet of the generalized S-transform (GST) in the paper is a modulated harmonic wave with four undetermined parameters that can be constructed by adjusting the four parameters to make the GST more suitable for seismic signals processing. The SSGST method squeezes and reconstructs the complex coefficient spectra of GST results along the frequency direction so that the energy distributions on the time-frequency spectra are concentrated around the real instantaneous frequency of the signal; thus, the time-frequency resolution can be improved. Based on mathematical theory, the basic principle of the new transformation method is given, and the mathematical expressions of the positive transformation and lossless inverse transformation of the method are strictly deduced. The experimental results of numerical signals illustrate that the proposed method can correctly decompose signals with different spectral characteristics into a high time-frequency resolution spectrum and can recovery the original signal from the time-frequency spectrum with satisfying reconstructing accuracy. Application on field seismic data shows the superiority of the new method in seismic time-frequency analysis for hydrocarbon detection. Full article

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10 pages, 4187 KiB

Open AccessArticle

Using a Molecular Dynamics Simulation to Investigate Asphalt Nano-Cracking under External Loading Conditions

by Yue Hou¹, Linbing Wang², Dawei Wang^3,*

, Xin Qu³ and Jiangfeng Wu¹

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

² Joint USTB-Virginia Tech Lab on Multifunctional Materials, USTB, Beijing 100083, China, Virginia Tech, Blacksburg, VA 24061, USA

³ Institute of Highway Engineering, RWTH Aachen University, D52074 Aachen, Germany

Appl. Sci. 2017, 7(8), 770; https://doi.org/10.3390/app7080770 - 28 Jul 2017

Cited by 31 | Viewed by 5472

Abstract

Recent research shows that macro-scale cracking in asphalt binder may originate from its intrinsic defects at the nano-scale. In this paper, a molecular dynamics (MD) simulation was conducted to evaluate the nucleation of natural defects in asphalt. The asphalt microstructure was modeled using [...] Read more.

Recent research shows that macro-scale cracking in asphalt binder may originate from its intrinsic defects at the nano-scale. In this paper, a molecular dynamics (MD) simulation was conducted to evaluate the nucleation of natural defects in asphalt. The asphalt microstructure was modeled using an ensemble of three different types of molecules to represent a constituent species: asphaltenes, naphthene aromatics and saturates, where the weight proportion of 20:60:20 was used to create an asphalt-like ensemble of molecules. Tension force was then applied on the molecular boundaries to study the crack initiation and propagation. It was discovered that the natural distribution of atoms at microscale would affect the intrinsic defects in asphalt and further influence crack initiation and propagation in asphalt. Full article

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

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10 pages, 2840 KiB

Open AccessArticle

A Biomechanical Study for Developing Wearable-Sensor System to Prevent Hip Fractures among Seniors

by Gongbing Shan^1,2,*, Xiang Zhang^1,2, Mingliang Meng² and Brandie Wilde¹

¹ Biomechanics Lab, Faculty of Arts & Science, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada

² Department of Physical Education, Xinzhou Teachers’ University, Xinzhou 034000, China

Appl. Sci. 2017, 7(8), 771; https://doi.org/10.3390/app7080771 - 30 Jul 2017

Cited by 7 | Viewed by 6333

Abstract

As the population ages, falls are becoming a major health problem, not only for those with some degree of balance or mobility impairment, but also among healthy active seniors. Previous studies suggest that the degradation of human sensorimotor function related to age contributes [...] Read more.

As the population ages, falls are becoming a major health problem, not only for those with some degree of balance or mobility impairment, but also among healthy active seniors. Previous studies suggest that the degradation of human sensorimotor function related to age contributes to falls. Hip bones are among the most frequently fractured body parts resulting from falls. Hip fractures are a frequent cause of early death, functional dependence, and high medical care costs. The current prevention method is to use hip protectors. Unfortunately, it often fails to do so because the pocket containing the pad can move away from the area during falls. Additionally, some seniors refuse to use hip protectors because they find them constraining. Hence, a new protector that is only activated during a fall is much desired. The current study explored the possibility via biomechanical analyses for building a wearable sensor system that triggers a mini-airbag system during a fall, i.e., the air-pad is only present for protection when a fall occurs. The results have revealed that two sensors placed on the left and right shoulder would be best for a detection of any-direction fall and could be applied for building a wearable sensor system for prevention of hip fractures resulting from falls. 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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14 pages, 9924 KiB

Open AccessArticle

Monitoring of Land-Surface Deformation in the Karamay Oilfield, Xinjiang, China, Using SAR Interferometry

by Yusupujiang Aimaiti^1,*, Fumio Yamazaki¹, Wen Liu¹

and Alimujiang Kasimu²

¹ Department of Urban Environment Systems, Chiba University, Chiba 263-8522, Japan

² Institute of Geographic Sciences and Tourism, Xinjiang Normal University, Urumqi 830054, Xinjiang, China

Appl. Sci. 2017, 7(8), 772; https://doi.org/10.3390/app7080772 - 30 Jul 2017

Cited by 26 | Viewed by 6323

Abstract

Synthetic Aperture Radar (SAR) interferometry is a technique that provides high-resolution measurements of the ground displacement associated with various geophysical processes. To investigate the land-surface deformation in Karamay, a typical oil-producing city in the Xinjiang Uyghur Autonomous Region, China, Advanced Land Observing Satellite [...] Read more.

Synthetic Aperture Radar (SAR) interferometry is a technique that provides high-resolution measurements of the ground displacement associated with various geophysical processes. To investigate the land-surface deformation in Karamay, a typical oil-producing city in the Xinjiang Uyghur Autonomous Region, China, Advanced Land Observing Satellite (ALOS) Phased Array L-band Synthetic Aperture Radar (PALSAR) data were acquired for the period from 2007 to 2009, and a two-pass differential SAR interferometry (D-InSAR) process was applied. The experimental results showed that two sites in the north-eastern part of the city exhibit a clear indication of land deformation. For a further evaluation of the D-InSAR result, the Persistent Scatterer (PS) and Small Baseline Subset (SBAS)-InSAR techniques were applied for 21 time series Environmental Satellite (ENVISAT) C-band Advanced Synthetic Aperture Radar (ASAR) data from 2003 to 2010. The comparison between the D-InSAR and SBAS-InSAR measurements had better agreement than that from the PS-InSAR measurement. The maximum deformation rate attributed to subsurface water injection for the period from 2003 to 2010 was up to approximately 33 mm/year in the line of sight (LOS) direction. The interferometric phase change from November 2007 to June 2010 showed a clear deformation pattern, and the rebound center has been expanding in scale and increasing in quantity. Full article

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20 pages, 2527 KiB

Open AccessArticle

Thermal Energy Diffusion Incorporating Generalized Einstein Relation for Degenerate Semiconductors

by Jang Jyegal

Department of Electronics Engineering, Incheon National University, Incheon 22012, Korea

Appl. Sci. 2017, 7(8), 773; https://doi.org/10.3390/app7080773 - 31 Jul 2017

Cited by 6 | Viewed by 6507

Abstract

The currently used generalized Einstein relation for degenerate semiconductors with isotropic nonparabolic energy bands produces physically improper results, as well as losing numerical accuracy for large values of nonparabolicity parameters at room temperature. Therefore, a new generalized Einstein relation (a macroscopic equation and [...] Read more.

The currently used generalized Einstein relation for degenerate semiconductors with isotropic nonparabolic energy bands produces physically improper results, as well as losing numerical accuracy for large values of nonparabolicity parameters at room temperature. Therefore, a new generalized Einstein relation (a macroscopic equation and a formula) is derived from the semiclassical momentum balance equation based on a drift-diffusion approximation, by introducing a new concept of the effective temperature of a carrier gas for generalization of the classical kinetic theory for nonideal gases of carriers in semiconductors. The proposed formula takes into account the carrier thermal energy diffusion effect completely, so that it can accurately reflect the effect of band nonparabolicity on the ratio of the diffusion coefficient to the mobility for carriers in degenerate semiconductors. From the results evaluated with the formula, new and critically important nonparabolicity effects are observed. It is shown that the new generalized Einstein relation is valid for applied electrical fields of the full linear regime. In addition, useful figures are also presented, from which the ratio of the diffusion coefficient to mobility, as well as the Fermi energy, can be easily determined from the electron concentration, or doping density, for a given semiconductor material. Full article

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15 pages, 630 KiB

Open AccessArticle

Electromagnetic Field Analysis of an Electric Dipole Antenna Based on a Surface Integral Equation in Multilayered Dissipative Media

by Yidong Xu¹

, Wei Xue^1,*, Yingsong Li^1,2,*

, Lili Guo¹ and Wenjing Shang¹

¹ College of Information and Communication Engineering, Harbin Engineering University, Harbin 150001, China

² National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China

Appl. Sci. 2017, 7(8), 774; https://doi.org/10.3390/app7080774 - 30 Jul 2017

Cited by 7 | Viewed by 4849

Abstract

In this paper, a novel method based on the Poggio–Miller–Chang-Harrington–Wu–Tsai (PMCHWT) integral equation is presented to study the electromagnetic fields excited by vertical or horizontal electric dipoles in the presence of a layered region which consists of K-layered dissipative media and the [...] Read more.

In this paper, a novel method based on the Poggio–Miller–Chang-Harrington–Wu–Tsai (PMCHWT) integral equation is presented to study the electromagnetic fields excited by vertical or horizontal electric dipoles in the presence of a layered region which consists of K-layered dissipative media and the air above. To transform the continuous integral equation into a block tridiagonal matrix with the feature of convenient solution, the Rao–Wilton–Glisson (RWG) functions are introduced as expansion and testing functions. The electromagnetic fields excited by an electric dipole are calculated and compared with the available results, where the electric dipole antenna is buried in the non-planar air–sea–seabed, air–rock–earth–mine, and multilayered sphere structures. The analysis and computations demonstrate that the method exhibits high accuracy and solving performance in the near field propagation region. Full article

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19 pages, 3112 KiB

Open AccessArticle

Planetary Gearbox Fault diagnosis via Joint Amplitude and Frequency Demodulation Analysis Based on Variational Mode Decomposition

by Zhipeng Feng¹

, Dong Zhang¹ and Ming J. Zuo^2,3,*

¹ School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China

² School of Mechatronics Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China

³ Department of Mechanical Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada

Appl. Sci. 2017, 7(8), 775; https://doi.org/10.3390/app7080775 - 30 Jul 2017

Cited by 42 | Viewed by 6835

Abstract

Planetary gearbox vibration signals have strong modulation features due to the amplitude modulation and frequency modulation (AM-FM) effect of gear faults, as well as the amplitude modulation (AM) effect of time-varying vibration transfer paths, on gear meshing vibrations. This results in an involute [...] Read more.

Planetary gearbox vibration signals have strong modulation features due to the amplitude modulation and frequency modulation (AM-FM) effect of gear faults, as well as the amplitude modulation (AM) effect of time-varying vibration transfer paths, on gear meshing vibrations. This results in an involute sidebands structure in Fourier spectrum, possibly misleading fault diagnosis. The modulating frequency of both amplitude modulation (AM) and frequency modulation (FM) parts is closely related to the gear fault characteristic frequency. This inspires the idea of joint amplitude and frequency demodulation analysis, thus addressing the complex sidebands issue inherent in Fourier spectrum. Demodulation analysis requires mono-component signals for accurate estimation of instantaneous frequency, and proper selection of an AM-FM component sensitive to gear fault. To this end, we firstly decompose the complex signal into intrinsic mode functions (IMFs) via variational mode decomposition (VMD), by exploiting its capability in decomposing complex modulated signal into constituent AM-FM components. For effective application of VMD in complex planetary gearbox signal analysis, we propose a method to determine a key parameter in VMD, i.e. the number of IMFs to be separated. For accurate instantaneous frequency estimation, we decompose IMFs via empirical AM-FM decomposition, to remove the influence of AM on instantaneous frequency estimation. Then, we select the sensitive IMF that contains the main gear fault information for further demodulation analysis. In order to properly select the sensitive IMF, we propose a criterion based on the gear vibration characteristics and the VMD properties. Finally, we obtain the amplitude and frequency demodulated spectra by applying Fourier transform to the amplitude envelope and instantaneous frequency of the selected sensitive IMF. According to the characteristics exhibited in the demodulated spectra, we can detect planetary gearbox fault. The proposed method is illustrated via a numerical simulated planetary gearbox vibration signal, and is further validated using lab experimental vibration signals of a planetary gearbox. Faults on all the three types of gear (sun, planet and ring) are successfully identified. Full article

(This article belongs to the Special Issue Deep Learning Based Machine Fault Diagnosis and Prognosis)

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21 pages, 4450 KiB

Open AccessArticle

Remote Servo Tuning System for Multi-Axis CNC Machine Tools Using a Virtual Machine Tool Approach

by Chien-Yu Lin and Ching-Hung Lee^*

Department of Mechanical Engineering, National Chung Hsing University, Taichung 40227, Taiwan

Appl. Sci. 2017, 7(8), 776; https://doi.org/10.3390/app7080776 - 30 Jul 2017

Cited by 15 | Viewed by 9945

Abstract

Servo systems affect the performances of machining in accuracy and surface quality for high speed and precision machine tools. This study introduces an efficient servo tuning technique for Computer Numerical Control (CNC) feed drive systems using particle swarm optimization (PSO) algorithm by virtual [...] Read more.

Servo systems affect the performances of machining in accuracy and surface quality for high speed and precision machine tools. This study introduces an efficient servo tuning technique for Computer Numerical Control (CNC) feed drive systems using particle swarm optimization (PSO) algorithm by virtual machine tool approach. The proposed approach contained a system identification phase and a servo tuning phase based on the same bandwidth for all axes feed drive systems. The PSO algorithm was adopted to obtain the system parameters and maximize the corresponding bandwidth. An efficient two-step servo tuning method based on gain and phase margins was proposed for high speed and precision requirements. All feed drive systems controller gains were optimized simultaneously for synchronization. A remote system called Machine Dr. was established for servo tuning and monitoring. Simulation and experimental results were introduced to illustrate the effectiveness of the proposed approach. Full article

(This article belongs to the Special Issue Selected Papers from the 2016 International Conference on Inventions)

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16 pages, 6495 KiB

Open AccessArticle

A Framework for Proactive Resource Provisioning in IaaS Clouds

by Yi-Hsuan Lee, Kuo-Chan Huang, Cheng-Hsien Wu, Yen-Hsuan Kuo and Kuan-Chou Lai^*

Department of Computer Science, National Taichung University of Education, Taichung 40306, Taiwan

Appl. Sci. 2017, 7(8), 777; https://doi.org/10.3390/app7080777 - 31 Jul 2017

Cited by 7 | Viewed by 4573

Abstract

Cloud computing is an emerging technology for rapidly provisioning and releasing resources on-demand from a shared resource pool. When big data is analyzed/mined on the cloud platform, the efficiency of resource provisioning would affect the system performance. This work proposes a framework for [...] Read more.

Cloud computing is an emerging technology for rapidly provisioning and releasing resources on-demand from a shared resource pool. When big data is analyzed/mined on the cloud platform, the efficiency of resource provisioning would affect the system performance. This work proposes a framework for proactive resource provisioning in IaaS (Infrastructure as a Service) clouds to improve system performance. The proposed framework consists of the virtual cluster computing system, the profiling system, the resource management system, and the monitoring system. In this framework, the over-commit mechanism is applied to improve resource utilization. Furthermore, a proactive task scheduling approach is also present to prevent the postponement of tasks in critical stages, especially when the amount of aggregated resources requested by virtual machines exceeds that of available resources on the over-committed physical machines. Experimental results show that the over-commit approach indeed improves the resource utilization. However, when the degree of applying the over-commit approach increases, the burden of this proposed approach also conceivably increases. Therefore, the proposed framework further applies the proactive task scheduling approach to execute the time-critical tasks earlier to shorten the processing time. A small-scale cloud system including 3 servers is built for experiments. Preliminary experimental results show the performance improvement of our proposed framework in IaaS clouds. Full article

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

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16 pages, 2786 KiB

Open AccessFeature PaperArticle

Removal of Crotamiton from Reverse Osmosis Concentrate by a TiO₂/Zeolite Composite Sheet

by Qun Xiang¹, Shuji Fukahori², Naoyuki Yamashita³, Hiroaki Tanaka³ and Taku Fujiwara^4,*

¹ The United Graduate School of Agricultural Sciences, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan

² Paper Industry Innovation Center of Ehime University, 127 Mendoricho Otsu, Shikokuchuo, Ehime 799-0113, Japan

³ Research Center for Environmental Quality Management, Kyoto University, 1-2 Yumihama, Otsu, Shiga 520-0811, Japan

⁴ Research and Education Faculty, National Sciences Cluster, Agriculture Unit, Kochi University, 200 Monobe Otsu, Nankoku, Kochi 783-8502, Japan

Appl. Sci. 2017, 7(8), 778; https://doi.org/10.3390/app7080778 - 31 Jul 2017

Cited by 13 | Viewed by 5722

Abstract

Reverse osmosis (RO) concentrate from wastewater reuse facilities contains concentrated emerging pollutants, such as pharmaceuticals. In this research, a paper-like composite sheet consisting of titanium dioxide (TiO₂) and zeolite was synthesized, and removal of the antipruritic agent crotamiton from RO concentrate [...] Read more.

Reverse osmosis (RO) concentrate from wastewater reuse facilities contains concentrated emerging pollutants, such as pharmaceuticals. In this research, a paper-like composite sheet consisting of titanium dioxide (TiO₂) and zeolite was synthesized, and removal of the antipruritic agent crotamiton from RO concentrate was studied using the TiO₂/zeolite composite sheet. The RO concentrate was obtained from a pilot-scale municipal secondary effluent reclamation plant. Effective immobilization of the two powders in the sheet made it easy to handle and to separate the photocatalyst and adsorbent from purified water. The TiO₂/zeolite composite sheet showed excellent performance for crotamiton adsorption without obvious inhibition by other components in the RO concentrate. With ultraviolet irradiation, crotamiton was simultaneously removed through adsorption and photocatalysis. The photocatalytic decomposition of crotamiton in the RO concentrate was significantly inhibited by the water matrix at high initial crotamiton concentrations, whereas rapid decomposition was achieved at low initial crotamiton concentrations. The major degradation intermediates were also adsorbed by the composite sheet. This result provides a promising method of mitigating secondary pollution caused by the harmful intermediates produced during advanced oxidation processes. The cyclic use of the HSZ-385/P25 composite sheet indicated the feasibility of continuously removing crotamiton from RO concentrate. Full article

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

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11 pages, 3166 KiB

Open AccessFeature PaperArticle

Mechanical Resilience of Modified Bitumen at Different Cooling Rates: A Rheological and Atomic Force Microscopy Investigation

by Cesare Oliviero Rossi^1,*

, Saltanat Ashimova^1,2, Pietro Calandra³, Maria Penelope De Santo⁴ and Ruggero Angelico^5,6,*

¹ Department of Chemistry and Chemical Technologies, University of Calabria, 87036 Arcavacata di Rende (CS), Italy

² Kazakhstan Highway Research Institute, Nurpeisova Str., 2A, Almaty 050061, Kazakhstan

³ CNR-ISMN, National Council of Research, Via Salaria km 29.300, 00015 Monterotondo Stazione (RM), Italy

⁴ Department of Physics and CNR-Nanotec, University of Calabria, 87036 Rende (CS), Italy

⁵ Department of Agricultural, Environmental and Food Sciences (DIAAA), University of Molise, Via De Sanctis, 86100 Campobasso (CB), Italy

⁶ CSGI (Center for Colloid and Surface Science), Via della Lastruccia 3, I-50019 Sesto Fiorentino (FI), Italy

Appl. Sci. 2017, 7(8), 779; https://doi.org/10.3390/app7080779 - 31 Jul 2017

Cited by 33 | Viewed by 5128

Abstract

Due to the wide variation in geographic and climatic conditions, the search for high-performance bituminous materials is becoming more and more urgent to increase the useful life of pavements and reduce the enormous cost of road maintenance. Extensive research has been done by [...] Read more.

Due to the wide variation in geographic and climatic conditions, the search for high-performance bituminous materials is becoming more and more urgent to increase the useful life of pavements and reduce the enormous cost of road maintenance. Extensive research has been done by testing various bitumen modifiers, although most of them are petroleum-derived additives, such as polymers, rubbers and plastic, which in turn do not prevent oxidative aging of the binder. Thus, as an alternative to the most common polymeric rheological modifiers, selected binder additives falling in the categories of organosilane (P2KA), polyphosphoric acid (PPA) and food grade phospholipids (LCS) were homogeneously mixed to a base bitumen. The goal was to analyse the micro-morphology of the bitumens (neat and modified) subjected to different cooling rates and to find the corresponding correlations in the mechanical response domain. Therefore, microstructural investigations carried out by Atomic Force Microscopy (AFM) and fundamental rheological tests based on oscillatory dynamic rheology, were used to evaluate the effect of additives on the bitumen structure and compared with pristine binder as a reference. The tested bitumen additives have been shown to elicit different mechanical behaviours by varying the cooling rate. By comparing rheological data, analysed in the framework of the “weak gel” model, and AFM images, it was found that both P2KA and PPA altered the material structure in a different manner whereas LCS revealed superior performances, acting as “mechanical buffer” in the whole explored range of cooling rates. Full article

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

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15 pages, 3598 KiB

Open AccessArticle

An Improved Dispatching Method (a-HPDB) for Automated Material Handling System with Active Rolling Belt for 450 mm Wafer Fabrication

by Chia-Nan Wang^1,*, Hsien-Pin Hsu^2,* and Van-Vinh Tran¹

¹ Department of Industrial Engineering and Management, National Kaohsiung University of Applied Sciences, 80778 Kaohsiung, Taiwan

² Department of Supply Chain Management, National Kaohsiung Marine University, 81157 Kaohsiung, Taiwan

Appl. Sci. 2017, 7(8), 780; https://doi.org/10.3390/app7080780 - 31 Jul 2017

Cited by 6 | Viewed by 5483

Abstract

The semiconductor industry is facing the transition from 300 mm to 450 mm wafer fabrication. Due to the increased size and weight, 450 mm wafers will pose unprecedented challenges on semiconductor wafer fabrication. To better handle and transport 450 mm wafers, an advanced [...] Read more.

The semiconductor industry is facing the transition from 300 mm to 450 mm wafer fabrication. Due to the increased size and weight, 450 mm wafers will pose unprecedented challenges on semiconductor wafer fabrication. To better handle and transport 450 mm wafers, an advanced Automated Material Handling System (AMHS) is definitely required. Though conveyor-based AMHS is expected to be suitable for 450 mm wafer fabrication, still it faces two main problems, traffic-jam problem and lot-prioritization. To address the two problems, in this research we have proposed an improved dispatching method, termed Heuristic Preemptive Dispatching Method using Activated Roller Belt (a-HPDB). We have developed some effective rules for the a-HPDB based on Activated Roller Belt (ARB). In addition, we have conducted experiments to investigate its effectiveness. Compared with the HPDB and R-HPD, two dispatching rules proposed in previous studies, our experimental results showed the a-HPDB had a better performance in terms of average lot delivery time (ALDT). For hot lots and normal lots, the a-HPDB had advantages of 4.14% and 8.92% over the HPDB and advantages of 4.89% and 8.52% over R-HPD, respectively. Full article

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

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10 pages, 4250 KiB

Open AccessArticle

A New Damage Assessment Method by Means of Neural Network and Multi-Sensor Satellite Data

by Alessandro Piscini^*, Vito Romaniello, Christian Bignami

and Salvatore Stramondo

Istituto Nazionale di Geofisica e Vulcanologia, 00143 Roma, Italy

Appl. Sci. 2017, 7(8), 781; https://doi.org/10.3390/app7080781 - 1 Aug 2017

Cited by 13 | Viewed by 4973

Abstract

Artificial Neural Network (ANN) is a valuable and well-established inversion technique for the estimation of geophysical parameters from satellite images. After training, ANNs are able to generate very fast products for several types of applications. Satellite remote sensing is an efficient way to [...] Read more.

Artificial Neural Network (ANN) is a valuable and well-established inversion technique for the estimation of geophysical parameters from satellite images. After training, ANNs are able to generate very fast products for several types of applications. Satellite remote sensing is an efficient way to detect and map strong earthquake damage for contributing to post-disaster activities during emergency phases. This work aims at presenting an application of the ANN inversion technique addressed to the evaluation of building collapse ratio (CR), defined as the number of collapsed buildings with respect to the total number of buildings in a city block, by employing optical and SAR satellite data. This is done in order to directly relate changes in images with damage that has occurred during strong earthquakes. Furthermore, once they have been trained, neural networks can be used rapidly at application stage. The goal was to obtain a general tool suitable for re-use in different scenarios. An ANN has been implemented in order to emulate a regression model and to estimate the CR as a continuous function. The adopted ANN has been trained using some features obtained from optical and Synthetic Aperture Radar (SAR) images, as inputs, and the corresponding values of collapse ratio obtained from the survey of the 2010 M7 Haiti Earthquake, i.e., as target output. As regards the optical data, we selected three change parameters: the Normalized Difference Index (NDI), the Kullback–Leibler divergence (KLD), and Mutual Information (MI). Concerning the SAR images, the Intensity Correlation Difference (ICD) and the KLD parameters have been considered. Exploiting an object-oriented approach, a segmentation of the study area into several regions has been performed. In particular, damage maps have been generated by considering a set of polygons (in which satellite parameters have been calculated) extracted from the open source Open Street Map (OSM) geo-database. The trained ANN has been proposed for the M6.0 Amatrice earthquake that occurred on 24 August 2016, in central Italy, by using the features extracted from Sentinel-2 and COSMO-SkyMed images as input. The results show that the ANN is able to retrieve a building collapse ratio with good accuracy. In particular, the fusion approach modelled the collapse ratio characterized by high values of CR (more than 0.5) over the historical center that agrees with observed damages. Since the technique is independent from different typologies of input data (i.e., for radiometric or spatial resolution characteristics), the study demonstrated the strength of the proposed approach for estimating damaged areas and its importance in near real time monitoring activities, owing to its fast application. Full article

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

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13 pages, 2258 KiB

Open AccessArticle

Enhancement of Sea Wave Potential Energy with Under-Sea Periodic Structures: A Simulation and Laboratory Study

by Shuo-Feng Chiu

, Jyun-Jie Wang, Ssu-Che Wang and Sheng D. Chao^*

Institute of Applied Mechanics, National Taiwan University, Taipei 10617, Taiwan

Appl. Sci. 2017, 7(8), 782; https://doi.org/10.3390/app7080782 - 2 Aug 2017

Cited by 2 | Viewed by 4012

Abstract

This paper is devoted to a theoretical investigation on the wave amplitude enhancement of surface sea water waves with under-sea periodic arrays of cylinders. A two-dimensional shallow water wave equation is derived and solved by using the plane-wave expansion method. The lattice types [...] Read more.

This paper is devoted to a theoretical investigation on the wave amplitude enhancement of surface sea water waves with under-sea periodic arrays of cylinders. A two-dimensional shallow water wave equation is derived and solved by using the plane-wave expansion method. The lattice types studied here include triangular, square and hexagonal lattices. These under-sea structures alter the sea bottom topography and induce constructive interference on the surface water waves. Given that the wave potential energy is dependent on the square of the wave amplitude, this mechanism can thus be used to increase the potential energy. It is shown that the enhancement factor depends on two geometric parameters and the maximum wave amplitude can be found by adjusting the two geometric parameters. Among the lattice types, the triangular and square lattice structures can induce more wave amplitude enhancement (and thus potential energy) than the hexagonal structures. Guided by numerical simulations, we have performed a reduced-scale water tank experiment to demonstrate the feasibility of the proposed idea. Preliminary experimental results show promising evidence of the predicted wave amplitude enhancement, suggesting perspective real-scale nearshore deployment and test. Full article

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

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21 pages, 2314 KiB

Open AccessFeature PaperArticle

Comparison of Basic Notch Filters for Semiconductor Optical Amplifier Pattern Effect Mitigation

by Zoe V. Rizou^1,*, Kyriakos E. Zoiros¹ and Antonios Hatziefremidis²

¹ Democritus University of Thrace, Department of Electrical and Computer Engineering, Laboratory of Telecommunications Systems, Lightwave Communications Research Group, Xanthi 67 100, Greece

² Technological Educational Institute of Chalkis, Department of Aircraft Technology, Chalkis 34 100, Greece

Appl. Sci. 2017, 7(8), 783; https://doi.org/10.3390/app7080783 - 2 Aug 2017

Cited by 8 | Viewed by 5007

Abstract

We conduct a thorough comparison of two basic notch filters employed to mitigate the pattern effect that manifests when semiconductor optical amplifiers (SOAs) serve linear amplification purposes. The filters are implemented using as the building architecture the optical delay interferometer (ODI) and the [...] Read more.

We conduct a thorough comparison of two basic notch filters employed to mitigate the pattern effect that manifests when semiconductor optical amplifiers (SOAs) serve linear amplification purposes. The filters are implemented using as the building architecture the optical delay interferometer (ODI) and the microring resonator (MRR). We formulate and follow a rational procedure, which involves identifying and applying the appropriate conditions for the filters’ spectral response slope related to the SOA pattern effect suppression mechanism. We thus extract the values of the free spectral range and detuning of each filter, which allow one to equivocally realize the pursued comparison. We define suitable performance metrics and obtain simulation results for each filter. The quantitative comparison reveals that most employed metrics are better with the MRR than with the ODI. Although the difference in performance is small, it is sufficient to justify considering also using the MRR for the intended purpose. Finally, we concisely discuss practical implementation issues of these notch filters and further make a qualitative comparison between them in terms of their inherent advantages and disadvantages. This discussion reveals that each scheme has distinct features that render it appropriate for supporting SOA direct signal amplification applications with a suppressed pattern effect. Full article

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

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10 pages, 3389 KiB

Open AccessArticle

Comparative Performance of Thermoacoustic Heat Exchangers with Different Pore Geometries in Oscillatory Flow. Implementation of Experimental Techniques

by Antonio Piccolo^1,*

, Roberto Siclari¹, Fabrizio Rando¹ and Mauro Cannistraro²

¹ Department of Engineering, University of Messina, Contrada di Dio, 98166 S. Agata (Messina), Italy

² Department of Architecture, University of Ferrara, Via della Ghiara 36, 44121 Ferrara, Italy

Appl. Sci. 2017, 7(8), 784; https://doi.org/10.3390/app7080784 - 2 Aug 2017

Cited by 30 | Viewed by 5868

Abstract

Heat exchangers (HXs) constitute key components of thermoacoustic devices and play an important role in determining the overall engine performance. In oscillatory flow conditions, however, standard heat transfer correlations for steady flows cannot be directly applied to thermoacoustic HXs, for which reliable and [...] Read more.

Heat exchangers (HXs) constitute key components of thermoacoustic devices and play an important role in determining the overall engine performance. In oscillatory flow conditions, however, standard heat transfer correlations for steady flows cannot be directly applied to thermoacoustic HXs, for which reliable and univocal design criteria are still lacking. This work is concerned with the initial stage of a research aimed at studying the thermal performance of thermoacoustic HXs. The paper reports a detailed discussion of the design and fabrication of the experimental set-up, measurement methodology and test-HXs characterized by two different pore geometries, namely a circular pore geometry and a rectangular (i.e., straight fins) pore geometry. The test rig is constituted by a standing wave engine where the test HXs play the role of ambient HXs. The experiment is conceived to allow the variation of a range of testing conditions such as drive ratio, operation frequency, acoustic particle velocity, etc. The procedure for estimating the gas side heat transfer coefficient for the two involved geometries is described. Some preliminary experimental results concerning the HX with straight fins are also shown. The present research could help in achieving a deeper understanding of the heat transfer processes affecting HXs under oscillating flow regime and in developing design optimization procedures. Full article

(This article belongs to the Special Issue Heat Transfer Processes in Oscillatory Flow Conditions)

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13 pages, 1401 KiB

Open AccessArticle

An Efficient Synthesis of Novel Pyrazole-Based Heterocycles as Potential Antitumor Agents

by Magda A. Abdallah¹, Sobhi M. Gomha^1,*

, Ikhlass M. Abbas¹, Mariam S. H. Kazem², Seham S. Alterary³ and Yahia N. Mabkhot^3,*

¹ Department of Chemistry, Faculty of Science, Cairo University, Giza 12613, Egypt

² Department of Chemistry, Faculty of Dentistry, October University for Modern Science & Arts, Giza 12613, Egypt

³ Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia

Appl. Sci. 2017, 7(8), 785; https://doi.org/10.3390/app7080785 - 3 Aug 2017

Cited by 29 | Viewed by 5156

Abstract

A new series of pyrazolylpyridines was prepared by reaction of ethyl-3-acetyl-1,5-diphenyl-1H-pyrazole-4-carboxylate with the appropriate aldehyde, malononitrile, or ethyl acetoacetate and an excess of ammonium acetate under reflux in acetic acid. Similarly, two novel bipyridine derivatives were prepared by the above reaction [...] Read more.

A new series of pyrazolylpyridines was prepared by reaction of ethyl-3-acetyl-1,5-diphenyl-1H-pyrazole-4-carboxylate with the appropriate aldehyde, malononitrile, or ethyl acetoacetate and an excess of ammonium acetate under reflux in acetic acid. Similarly, two novel bipyridine derivatives were prepared by the above reaction using terephthaldehyde in lieu of benzaldehyde derivatives. In addition, a series of 1,2,4-triazolo[4,3-a]pyrimidines was synthesized by a reaction of 6-(pyrazol-3-yl)pyrimidine-2-thione with a number of hydrazonoyl chlorides in dioxane and in the presence of triethylamine. The structure of the produced compounds was established by elemental analyses and spectral methods, and the mechanisms of their formation was discussed. Furthermore, the pyrazolyl-pyridine derivatives were tested as anticancer agents and the results obtained showed that some of them revealed high activity against human hepatocellular carcinoma (HEPG2) cell lines. Full article

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

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17 pages, 5717 KiB

Open AccessArticle

A Feature-Based Structural Measure: An Image Similarity Measure for Face Recognition

by Noor Abdalrazak Shnain¹, Zahir M. Hussain^2,3,*

and Song Feng Lu¹

¹ School of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China

² Faculty of Computer Science & Mathematics, University of Kufa, Najaf 54001, Iraq

³ School of Engineering, Edith Cowan University, Perth, WA 6027, Australia

Appl. Sci. 2017, 7(8), 786; https://doi.org/10.3390/app7080786 - 3 Aug 2017

Cited by 37 | Viewed by 9954

Abstract

Facial recognition is one of the most challenging and interesting problems within the field of computer vision and pattern recognition. During the last few years, it has gained special attention due to its importance in relation to current issues such as security, surveillance [...] Read more.

Facial recognition is one of the most challenging and interesting problems within the field of computer vision and pattern recognition. During the last few years, it has gained special attention due to its importance in relation to current issues such as security, surveillance systems and forensics analysis. Despite this high level of attention to facial recognition, the success is still limited by certain conditions; there is no method which gives reliable results in all situations. In this paper, we propose an efficient similarity index that resolves the shortcomings of the existing measures of feature and structural similarity. This measure, called the Feature-Based Structural Measure (FSM), combines the best features of the well-known SSIM (structural similarity index measure) and FSIM (feature similarity index measure) approaches, striking a balance between performance for similar and dissimilar images of human faces. In addition to the statistical structural properties provided by SSIM, edge detection is incorporated in FSM as a distinctive structural feature. Its performance is tested for a wide range of PSNR (peak signal-to-noise ratio), using ORL (Olivetti Research Laboratory, now AT&T Laboratory Cambridge) and FEI (Faculty of Industrial Engineering, São Bernardo do Campo, São Paulo, Brazil) databases. The proposed measure is tested under conditions of Gaussian noise; simulation results show that the proposed FSM outperforms the well-known SSIM and FSIM approaches in its efficiency of similarity detection and recognition of human faces. Full article

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19 pages, 2264 KiB

Open AccessArticle

A Novel Reactive Power Optimization in Distribution Network Based on Typical Scenarios Partitioning and Load Distribution Matching Method

by Yuqi Ji^1,2

, Keyan Liu^2,*

, Guangfei Geng^1,*, Wanxing Sheng², Xiaoli Meng², Dongli Jia² and Kaiyuan He²

¹ College of Information and Electrical Engineering, China Agricultural University, Beijing 100083, China

² Power Distribution Research Department, China Electric Power Research Institute, Beijing 100192, China

Appl. Sci. 2017, 7(8), 787; https://doi.org/10.3390/app7080787 - 3 Aug 2017

Cited by 3 | Viewed by 3641

Abstract

This paper proposed an entropy weight optimum seeking method (EWOSM) based on the typical scenarios partitioning and load distribution matching, to solve the reactive power optimization problem in distribution network under the background of big data. Firstly, the mathematic model of reactive power [...] Read more.

This paper proposed an entropy weight optimum seeking method (EWOSM) based on the typical scenarios partitioning and load distribution matching, to solve the reactive power optimization problem in distribution network under the background of big data. Firstly, the mathematic model of reactive power optimization is provided to analyze the relationship between the data source and the optimization schemes in distribution network, which illustrate the feasibility of using large amount of historical data to solve reactive power optimization. Then, the typical scenarios partitioning method and load distribution matching method are presented, which can select out some loads that have the same or similar distributions with the load to be optimized from historical database rapidly, and the corresponding historical optimization schemes are used as the alternatives. As the reactive power optimization is a multi-objective problem, the multi-attribute decision making method based on entropy weight method is used to select out the optimal scheme from the alternatives. The objective weights of evaluation indexes are determined by entropy weight method, and then the multi-attribute decision making problem is transformed to a single attribute decision making problem. Finally, the proposed method is tested on several systems with different scales and compared with existing methods to prove the validity and superiority. Full article

(This article belongs to the Section Mechanical Engineering)

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3 pages, 172 KiB

Open AccessEditorial

Guest Editors’ Note—Special Issue on Spatial Audio

by Woon-Seng Gan^1,*

and Jung-Woo Choi²

¹ Digital Signal Processing Lab, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore

² School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea

Appl. Sci. 2017, 7(8), 788; https://doi.org/10.3390/app7080788 - 3 Aug 2017

Viewed by 4352

Abstract

Three-dimensional (or spatial) audio is a growing research field that plays a key role in realizing immersive communication in many of today’s applications for teleconferencing, entertainment, gaming, navigation guidance, and virtual reality (VR)/augmented reality (AR).[...] Full article

(This article belongs to the Special Issue Spatial Audio)

3 pages, 143 KiB

Open AccessEditorial

Structural Health Monitoring (SHM) of Civil Structures

by Gangbing Song^1,*, Chuji Wang^2,* and Bo Wang^3,*

¹ Department of Mechanical Engineering, University of Houston, Houston, TX 77204, USA

² Department of Physics and Astronomy, Mississippi State University, Starkville, MS 39762, USA

³ School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China

Appl. Sci. 2017, 7(8), 789; https://doi.org/10.3390/app7080789 - 4 Aug 2017

Cited by 108 | Viewed by 10152

Abstract

As newer and more reliable ways of construction were developed, civilization began to spread out further and retain functional infrastructure for longer periods of time.[...] Full article

(This article belongs to the Special Issue Structural Health Monitoring (SHM) of Civil Structures)

15 pages, 13599 KiB

Open AccessArticle

Experimental Tests and Aeroacoustic Simulations of the Control of Cavity Tone by Plasma Actuators

by Hiroshi Yokoyama^*

, Isamu Tanimoto and Akiyoshi Iida

Department of Mechanical Engineering, Toyohashi University of Technology, Toyohashi 441-8580, Japan

Appl. Sci. 2017, 7(8), 790; https://doi.org/10.3390/app7080790 - 4 Aug 2017

Cited by 15 | Viewed by 6410

Abstract

A plasma actuator comprising a dielectric layer sandwiched between upper and lower electrodes can induce a flow from the upper to lower electrode by means of an externally-applied electric field. Our objective is to clarify the mechanism by which such actuators can control [...] Read more.

A plasma actuator comprising a dielectric layer sandwiched between upper and lower electrodes can induce a flow from the upper to lower electrode by means of an externally-applied electric field. Our objective is to clarify the mechanism by which such actuators can control the cavity tone. Plasma actuators, with the electrodes elongated in the streamwise direction and aligned in the spanwise direction, were placed in the incoming boundary of a deep cavity with a depth-to-length ratio of 2.5. By using this experimental arrangement, the amount of sound reduction (“control effect”) produced by actuators of differing dimensions was measured. Direct aeroacoustic simulations were performed for controlling the cavity tone by using these actuators, where the distributions of the body forces applied by the actuators were determined from measurements of the plasma luminescence. The predicted control effects on the flow and sound fields were found to agree well with the experimental results. The simulations show that longitudinal streamwise vortices are introduced in the incoming boundary by the actuators, and the vortices form rib structures in the cavity flow. These vortices distort and weaken the two-dimensional vortices responsible for producing the cavity tone, causing the tonal sound to be reduced. Full article

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

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21 pages, 3630 KiB

Open AccessArticle

Reliability-Based and Cost-Oriented Product Optimization Integrating Fuzzy Reasoning Petri Nets, Interval Expert Evaluation and Cultural-Based DMOPSO Using Crowding Distance Sorting

by Zhaoxi Hong^1,2, Yixiong Feng^1,2,*

, Zhongkai Li³, Guangdong Tian^4,* and Jianrong Tan^1,2

¹ State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China

² Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province, Zhejiang University, Hangzhou 310027, China

³ School of Mechatronics Engineering, University of Mining and Technology, Xuzhou 221116, China

⁴ Transportation College, Jilin University, Changchun 130020, China

Appl. Sci. 2017, 7(8), 791; https://doi.org/10.3390/app7080791 - 4 Aug 2017

Cited by 18 | Viewed by 4732

Abstract

In reliability-based and cost-oriented product optimization, the target product reliability is apportioned to subsystems or components to achieve the maximum reliability and minimum cost. Main challenges to conducting such optimization design lie in how to simultaneously consider subsystem division, uncertain evaluation provided by [...] Read more.

In reliability-based and cost-oriented product optimization, the target product reliability is apportioned to subsystems or components to achieve the maximum reliability and minimum cost. Main challenges to conducting such optimization design lie in how to simultaneously consider subsystem division, uncertain evaluation provided by experts for essential factors, and dynamic propagation of product failure. To overcome these problems, a reliability-based and cost-oriented product optimization method integrating fuzzy reasoning Petri net (FRPN), interval expert evaluation and cultural-based dynamic multi-objective particle swarm optimization (DMOPSO) using crowding distance sorting is proposed in this paper. Subsystem division is performed based on failure decoupling, and then subsystem weights are calculated with FRPN reflecting dynamic and uncertain failure propagation, as well as interval expert evaluation considering six essential factors. A mathematical model of reliability-based and cost-oriented product optimization is established, and the cultural-based DMOPSO with crowding distance sorting is utilized to obtain the optimized design scheme. The efficiency and effectiveness of the proposed method are demonstrated by the numerical example of the optimization design for a computer numerically controlled (CNC) machine tool. Full article

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

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15 pages, 3569 KiB

Open AccessArticle

Contact Pressure and Strain Energy Density of Hyperelastic U-shaped Monolithic Seals under Axial and Radial Compressions in an Insulating Joint: A Numerical Study

by Jinmu Jung¹, Inhwan Hwang² and Donghwan Lee^1,3,*

¹ Division of Mechanical Design Engineering, College of Engineering, Chonbuk National University, Jeonju 54896, Korea

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

³ Hemorheology Research Institute, College of Engineering, Chonbuk National University, Jeonju 54896, Korea

Appl. Sci. 2017, 7(8), 792; https://doi.org/10.3390/app7080792 - 4 Aug 2017

Cited by 5 | Viewed by 8343

Abstract

In insulation joints, elastomeric U-shaped monolithic seals (UMSs) are replacing O-ring systems because of their enhanced sealing capabilities for the oil and gas industries. UMSs are compressed axially during assembly and radially when pressurized in operation. The reliability of UMSs due to the [...] Read more.

In insulation joints, elastomeric U-shaped monolithic seals (UMSs) are replacing O-ring systems because of their enhanced sealing capabilities for the oil and gas industries. UMSs are compressed axially during assembly and radially when pressurized in operation. The reliability of UMSs due to the displacement imposed during assembly and the internal pressure in operation is influenced by the axial compression ratio, thickness ratio (TR), and geometric complexity. In this study, the hyperelastic behavior of elastomeric UMSs under axial and radial compressions is investigated using axisymmetric finite-element analysis. Twelve examples of UMSs with three geometric restraints (open grooves on both sides (type 1), an open groove on one side only (type 2), and no groove (type 3)) and four thickness ratios (TR = 0.25, 0.50, 1.00, and 1.50) are evaluated. To analyze nonlinear elastomeric materials, neo-Hookean constitutive equations are applied and the UMSs are considered as being a nearly incompressible hyperelastic material with a Poisson’s ratio of 0.499. The failure and detachment risks of UMSs are analyzed in terms of the equivalent stress, gap distance, contact pressure, and strain energy density. It is advantageous that the smaller the TR, the smaller the stress distribution. However, the generation of broader detachment regions is observed. Type 1 symmetrically shows the lowest stress distribution and the smallest detachment region, whereas type 3 symmetrically shows the highest values. Type 3 (TR = 0.25) shows the broadest detachment region in the arc-length range from −15.7 to 15.7 mm, whereas the largest gap of 0.7 mm is observed in type 2 (TR = 0.5). For all types, the detachment region disappears completely at TR = 1.0 or higher, which implies that full sealing is occurring. The average contact pressure increases exponentially during axial compression (in assembly) and linearly during radial compression (in operation). The largest contact pressure of 31.5 MPa is observed in type 3 (TR = 1.5), while the lowest is observed in type 1 (TR = 0.25). As for the strain energy density, type 3 at TR = 0.25 shows the largest increase in the strain energy density with 1.75 MJ/m³, while type 1 shows the most stable values of all cases. In conclusion, the lowest risk of failure of a nonlinear hyperelastic UMS was investigated numerically with minor equivalent stress and detachment region with higher contact pressure, which can be taken into account to ensure the reliability of the UMS. Full article

(This article belongs to the Special Issue Viscoelastic Solids: Mechanical Behaviour, Contact Mechanics, Fracture and Wear)

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10 pages, 1911 KiB

Open AccessFeature PaperArticle

Effect of Organic Stabilizers on Silver Nanoparticles Fabricated by Femtosecond Pulsed Laser Ablation

by Pablo Díaz-Núñez^1,2, Jesús González-Izquierdo², Guillermo González-Rubio^3,4, Andrés Guerrero-Martínez³

, Antonio Rivera¹, José Manuel Perlado¹, Luis Bañares³ and Ovidio Peña-Rodríguez^1,*

¹ Instituto de Fusión Nuclear, Universidad Politécnica de Madrid, José Gutiérrez Abascal 2, 28006 Madrid, Spain

² Centro de Láseres Ultrarrápidos, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain

³ Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain

⁴ BioNanoPlasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia, Spain

Appl. Sci. 2017, 7(8), 793; https://doi.org/10.3390/app7080793 - 4 Aug 2017

Cited by 14 | Viewed by 6117

Abstract

Laser ablation has several advantages over the chemical synthesis of nanoparticles due to its simplicity and because it is a faster and cleaner process. In this paper, we use femtosecond laser ablation to generate highly concentrated silver colloidal nanoparticle solutions. Those high concentrations [...] Read more.

Laser ablation has several advantages over the chemical synthesis of nanoparticles due to its simplicity and because it is a faster and cleaner process. In this paper, we use femtosecond laser ablation to generate highly concentrated silver colloidal nanoparticle solutions. Those high concentrations usually lead to agglomeration of the nanoparticles, rendering the solution nearly useless. We employ two different organic stabilizers (hexadecyltrimethylammonium bromide, CTAB, and polyvinylpyrrolidone, PVP) to avoid this problem and study their effect on the nanoparticle size distribution, structural characteristics, and the solution concentration. Full article

(This article belongs to the Special Issue Laser Interaction with Plasmonic Nanostructures)

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11 pages, 1105 KiB

Open AccessArticle

Improving Asphalt Mixture Performance by Partially Replacing Bitumen with Waste Motor Oil and Elastomer Modifiers

by Sara Fernandes¹, Joana Peralta², Joel R. M. Oliveira¹

, R. Christopher Williams³ and Hugo M. R. D. Silva^1,*

¹ CTAC, Centre for Territory, Environment and Construction, University of Minho, 4800 058 Guimarães, Portugal

² Wacker Chemical Corporation, 6870 Tilghman Street, Allentown, PA 18106-9346, USA

³ Department of Civil, Construction and Environmental Engineering, Iowa State University, Ames, IA 50011-3232, USA

Appl. Sci. 2017, 7(8), 794; https://doi.org/10.3390/app7080794 - 5 Aug 2017

Cited by 48 | Viewed by 7404

Abstract

The environmental concern about waste generation and the gradual decrease of oil reserves has led the way to finding new waste materials that may partially replace the bitumens used in the road paving industry. Used motor oil from vehicles is a waste product [...] Read more.

The environmental concern about waste generation and the gradual decrease of oil reserves has led the way to finding new waste materials that may partially replace the bitumens used in the road paving industry. Used motor oil from vehicles is a waste product that could answer that demand, but it can also drastically reduce the viscosity, increasing the asphalt mixture’s rutting potential. Therefore, polymer modification should be used in order to avoid compromising the required performance of asphalt mixtures when higher amounts of waste motor oil are used. Thus, this study was aimed at assessing the performance of an asphalt binder/mixture obtained by replacing part of a paving grade bitumen (35/50) with 10% waste motor oil and 5% styrene-butadiene-styrene (SBS) as an elastomer modifier. A comparison was also made with the results of a previous study using a blend of bio-oil from fast pyrolysis and ground tire rubber modifier as a partial substitute for usual PG64-22 bitumen. The asphalt binders were tested by means of Fourier infrared spectra and dynamic shear rheology, namely by assessing their continuous high-performance grade. Later, the water sensitivity, fatigue cracking resistance, dynamic modulus and rut resistance performance of the resulting asphalt mixtures was evaluated. It was concluded that the new binder studied in this work improves the asphalt mixture’s performance, making it an excellent solution for paving works. Full article

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

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22 pages, 2705 KiB

Open AccessArticle

An Innovative Dual-Column System for Heavy Metallic Ion Sorption by Natural Zeolite

by Amanda L. Ciosek^*

and Grace K. Luk

Department of Civil Engineering, Faculty of Engineering and Architectural Science, Ryerson University, Toronto, ON M5B 2K3, Canada

Appl. Sci. 2017, 7(8), 795; https://doi.org/10.3390/app7080795 - 5 Aug 2017

Cited by 10 | Viewed by 6456

Abstract

This study investigates the design and performance of a novel sorption system containing natural zeolite. The apparatus consists of packed, fixed-bed, dual-columns with custom automated controls and sampling chambers, connected in series and stock fed by a metering pump at a controlled adjustable [...] Read more.

This study investigates the design and performance of a novel sorption system containing natural zeolite. The apparatus consists of packed, fixed-bed, dual-columns with custom automated controls and sampling chambers, connected in series and stock fed by a metering pump at a controlled adjustable distribution. The purpose of the system is to remove heavy metallic ions predominately found in acid mine drainage, including lead (Pb²⁺), copper (Cu²⁺), iron (Fe³⁺), nickel (Ni²⁺) and zinc (Zn²⁺), combined in equal equivalence to form an acidified total 10 meq/L aqueous solution. Reported trends on the zeolite’s preference to these heavy metallic ions is established in the system breakthrough curve, as Pb²⁺ >> Fe³⁺ > Cu²⁺ > Zn²⁺ >> Ni²⁺. Within a 3-h contact period, Pb²⁺ is completely removed from both columns. Insufficient Ni²⁺ removal is achieved by either column with the promptest breakthrough attained, as zeolite demonstrates the least affinity towards it; however, a 48.97% removal is observed in the cumulative collection at the completion of the analysis period. The empty bed contact times for the first and second columns are 20 and 30 min, respectively; indicating a higher bed capacity at breakthrough and a lower usage rate of the zeolite mineral in the second column. This sorption system experimentally demonstrates the potential for industrial wastewater treatment technology development. Full article

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

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10 pages, 1767 KiB

Open AccessArticle

A Method for Ferulic Acid Production from Rice Bran Oil Soapstock Using a Homogenous System

by Hoa Thi Truong^1,*

, Manh Do Van¹, Long Duc Huynh¹, Linh Thi Nguyen¹, Anh Do Tuan¹, Thao Le Xuan Thanh¹, Hung Duong Phuoc², Norimichi Takenaka³, Kiyoshi Imamura⁴ and Yasuaki Maeda⁴

¹ Danang Environmental Technology Center, Institute of Environmental Technology, Vietnam Academy of Science and Technology, Tran Dai Nghia Road, Ngu Hanh Son Dist., Da Nang 550000, Vietnam

² International Cooperation Department, Ministry of Natural Resources and Environment, 10 Ton That Thuyet St., Hanoi 100000, Vietnam

³ Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan

⁴ Research Organization for University-Community Collaborations, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan

Appl. Sci. 2017, 7(8), 796; https://doi.org/10.3390/app7080796 - 5 Aug 2017

Cited by 25 | Viewed by 9812

Abstract

Ferulic acid (FA) is widely used as an antioxidant, e.g., as a Ultraviolet (UV) protectant in cosmetics and in various medical applications. It has been produced by the hydrolysis of γ-oryzanol found in rice bran oil soapstock. In this study, the base-catalyzed, homogenous [...] Read more.

Ferulic acid (FA) is widely used as an antioxidant, e.g., as a Ultraviolet (UV) protectant in cosmetics and in various medical applications. It has been produced by the hydrolysis of γ-oryzanol found in rice bran oil soapstock. In this study, the base-catalyzed, homogenous hydrolysis of γ-oryzanol was conducted using various ratios of potassium hydroxide (KOH) to γ-oryzanol, initial concentrations of γ-oryzanol in the reaction mixture, and ratios of ethanol (EtOH) (as cosolvent)/ethyl acetate (EtOAc) (γ-oryzanol solution). Acceleration of the reaction using a planar type of ultrasound sonicator (78 and 130 kHz) at different reaction temperatures was explored. By using a heating method, the 80% yield of FA was attained at 75 °C in 4 h under homogeneous conditions (initial concentration of γ-oryzanol 12 mg/mL, the KOH/γ-oryzanol ratio (wt/wt) 10/1, and EtOH/EtOAc ratio (v/v) 5/1). With the assistance of 78 and 130 kHz irradiation, the yields reached 90%. The heating method was applied for the γ-oryzanol-containing extract prepared from rice bran oil soapstock. From soapstock, the 74.3% yield of FA was obtained, but 20% of the trans-FA in the reaction mixture was transformed into cis-form within one month. Full article

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

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18 pages, 1120 KiB

Open AccessArticle

Dynamic Performance Analysis for an Absorption Chiller under Different Working Conditions

by Jian Wang, Sheng Shang, Xianting Li, Baolong Wang, Wei Wu and Wenxing Shi^*

Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Department of Building Science, Tsinghua University, Beijing 100084, China

Appl. Sci. 2017, 7(8), 797; https://doi.org/10.3390/app7080797 - 5 Aug 2017

Cited by 19 | Viewed by 6274

Abstract

Due to the merits of energy saving and environmental protection, the absorption chiller (AC) has attracted a lot of attention, and previous studies only concentrated on the dynamic response of the AC under a single working condition. However, the working conditions are usually [...] Read more.

Due to the merits of energy saving and environmental protection, the absorption chiller (AC) has attracted a lot of attention, and previous studies only concentrated on the dynamic response of the AC under a single working condition. However, the working conditions are usually variable, and the dynamic performance under different working conditions is beneficial for the adjustment of AC and the control of the whole system, of which the stabilization can be affected by the AC transient process. Therefore, the steady and dynamic models of a single-effect H₂O-LiBr absorption chiller are built up, the thermal inertia and fluid storage are also taken into consideration. And the dynamic performance analyses of the AC are completed under different external parameters. Furthermore, a whole system using AC in a process plant is analyzed. As a conclusion, the time required to reach a new steady-state (relaxation time) increases when the step change of the generator inlet temperature becomes large, the cooling water inlet temperature rises, or the evaporator inlet temperature decreases. In addition, the control strategy considering the AC dynamic performance is favorable to the operation of the whole system. Full article

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

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14 pages, 3245 KiB

Open AccessFeature PaperArticle

Real-Time Recognition of Calling Pattern and Behaviour of Mobile Phone Users through Anomaly Detection and Dynamically-Evolving Clustering

by José Antonio Iglesias^1,*

, Agapito Ledezma¹, Araceli Sanchis¹ and Plamen Angelov²

¹ Computer Science Department, Carlos III University of Madrid, Leganés, Madrid 28918, Spain

² Computing and Communications Department, Lancaster University, Lancaster LA14WA, UK

Appl. Sci. 2017, 7(8), 798; https://doi.org/10.3390/app7080798 - 5 Aug 2017

Cited by 11 | Viewed by 5737

Abstract

In the competitive telecommunications market, the information that the mobile telecom operators can obtain by regularly analysing their massive stored call logs, is of great interest. Although the data that can be extracted nowadays from mobile phones have been enriched with much information, [...] Read more.

In the competitive telecommunications market, the information that the mobile telecom operators can obtain by regularly analysing their massive stored call logs, is of great interest. Although the data that can be extracted nowadays from mobile phones have been enriched with much information, the data solely from the call logs can give us vital information about the customers. This information is usually related with the calling behaviour of their customers and it can be used to manage them. However, the analysis of these data is normally very complex because of the vast data stream to analyse. Thus, efficient data mining techniques need to be used for this purpose. In this paper, a novel approach to analyse call detail records (CDR) is proposed, with the main goal to extract and cluster different calling patterns or behaviours, and to detect outliers. The main novelty of this approach is that it works in real-time using an evolving and recursive framework. Full article

(This article belongs to the Special Issue Human Activity Recognition)

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17 pages, 6343 KiB

Open AccessArticle

An Experimental Study on Hysteresis Characteristics of a Pneumatic Braking System for a Multi-Axle Heavy Vehicle in Emergency Braking Situations

by Zhe Wang^1,2,*

, Xiaojun Zhou^1,2, Chenlong Yang^1,2, Zhaomeng Chen^1,2

and Xuelei Wu³

¹ State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China

² Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province, Zhejiang University, Hangzhou 310027, China

³ Beijing Institute of Space Launch Technology, Beijing 100076, China

Appl. Sci. 2017, 7(8), 799; https://doi.org/10.3390/app7080799 - 6 Aug 2017

Cited by 26 | Viewed by 8102

Abstract

This study aims to investigate the hysteresis characteristics of a pneumatic braking system for multi-axle heavy vehicles (MHVs). Hysteresis affects emergency braking performance severely. The fact that MHVs have a large size and complex structure leads to more nonlinear coupling property of the [...] Read more.

This study aims to investigate the hysteresis characteristics of a pneumatic braking system for multi-axle heavy vehicles (MHVs). Hysteresis affects emergency braking performance severely. The fact that MHVs have a large size and complex structure leads to more nonlinear coupling property of the pneumatic braking system compared to normal two-axle vehicles. Thus, theoretical analysis and simulation are not enough when studying hysteresis. In this article, the hysteresis of a pneumatic brake system for an eight-axle vehicle in an emergency braking situation is studied based on a novel test bench. A servo drive device is applied to simulate the driver’s braking intensions normally expressed by opening or moving speed of the brake pedal. With a reasonable arrangement of sensors and the NI LabVIEW platform, both the delay time of eight loops and the response time of each subassembly in a single loop are detected in real time. The outcomes of the experiment show that the delay time of each loop gets longer with the increase of pedal opening, and a quadratic relationship exists between them. Based on this, the pressure transient in the system is fitted to a first-order plus time delay model. Besides, the response time of treadle valve and controlling pipeline accounts for more than 80% of the loop’s total delay time, indicating that these two subassemblies are the main contributors to the hysteresis effect. Full article

(This article belongs to the Special Issue Power Transmission and Control in Power and Vehicle Machineries)

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16 pages, 7514 KiB

Open AccessArticle

Research on Performance of a Dense Graded Ultra-Thin Wearing Course Mixture

by Lei Geng¹, Tao Ma^2,*, Junhui Zhang³, Xiaoming Huang² and Pengsen Hu²

¹ Jiangsu Sinoroad Engineering Research Institute Co. LTD., 19 Lanhua Road, Nanjing 211800, China

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

³ State Engineering Laboratory of Highway Maintenance Technology, Changsha University of Science and Technology, Changsha 410114, China

Appl. Sci. 2017, 7(8), 800; https://doi.org/10.3390/app7080800 - 7 Aug 2017

Cited by 26 | Viewed by 5139

Abstract

This paper focused on the design and performance characterization of a modified ultra-thin wearing course mixture (M-UWM). A dense graded ultra-thin wearing course mixture with nominal maximum aggregate size of 10 mm was designed and named as UWM10. A multi-chain polyolefin modifier was [...] Read more.

This paper focused on the design and performance characterization of a modified ultra-thin wearing course mixture (M-UWM). A dense graded ultra-thin wearing course mixture with nominal maximum aggregate size of 10 mm was designed and named as UWM10. A multi-chain polyolefin modifier was used to modify the performance of UWM10 to get M-UWM10. Based on different laboratory performance tests including wheel tracking tests, low-temperature bending beam tests, immersion Marshall tests and freeze-thaw splitting tests, the high temperature rutting resistance, low-temperature cracking resistance and moisture resistance of the designed M-UWM10 were evaluated. The texture depth tests and wheel tracking tests were combined to characterize the degradation behaviour of the surface texture depth of M-UWM10. Based on test roads, the bonding conditions between the wearing course layer that consisted of M-UWM10 and its sublayer were evaluated by computed tomography (CT) scanning test and pull out test. Filed texture depth tests were also conducted on the test roads. It is proved that the designed wearing course mixture M-UWM10 shows excellent pavement performance as well as better wearing resistance and interlayer bonding than the traditional wearing course mixture. Full article

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

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2 pages, 143 KiB

Open AccessEditorial

Energy Dissipation and Vibration Control: Modeling, Algorithm, and Devices

by Gangbing Song^1,2,*

, Steve C. S. Cai³ and Hong-Nan Li²

¹ Department of Mechanical Engineering, University of Houston, Houston, TX 77004, USA

² School of Civil Engineering, Dalian University of Technology, Dalian 116023, China

³ Department of Civil and Environmental Engineering, Louisiana State University, Baton Rouge, LA 70803, USA

Appl. Sci. 2017, 7(8), 801; https://doi.org/10.3390/app7080801 - 7 Aug 2017

Cited by 16 | Viewed by 3855

Abstract

The topic of vibration control and energy dissipation is among the oldest and most relevant in the field of engineering [...] Full article

(This article belongs to the Special Issue Energy Dissipation and Vibration Control: Modeling, Algorithm and Devices)

21 pages, 3682 KiB

Open AccessArticle

Effects of Vibration on the Electrical Performance of Lithium-Ion Cells Based on Mathematical Statistics

by Lijun Zhang^1,*

, Zhansheng Ning¹, Hui Peng¹, 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(8), 802; https://doi.org/10.3390/app7080802 - 7 Aug 2017

Cited by 54 | Viewed by 11117

Abstract

Lithium-ion batteries are increasingly used in mobile applications where mechanical vibrations and shocks are a constant companion. There is evidence both in the academic and industrial communities to suggest that the electrical performance and mechanical properties of the lithium-ion cells of an electric [...] Read more.

Lithium-ion batteries are increasingly used in mobile applications where mechanical vibrations and shocks are a constant companion. There is evidence both in the academic and industrial communities to suggest that the electrical performance and mechanical properties of the lithium-ion cells of an electric vehicle (EV) are affected by the road-induced vibration. However, only a few studies related to the effects of vibration on the degradation of electrical performance of lithium-ion batteries have been approached. Therefore, this paper aimed to investigate the effects of vibration on the DC resistance, 1C capacity and consistency of NCR18650BE lithium-ion cells. Based on mathematical statistics, the method changes of the DC resistance and the capacity of the cells both before and after the test were analyzed with a large sample size. The results identified that a significant increase in DC resistance was observed as a result of vibration at the 95% confidence level, while typically a reduction in 1C capacity was also noted. In addition, based on a multi-feature quantity, a clustering algorithm was adopted to analyze the effect of vibration on cell consistency; the results show that the cell consistency had deteriorated after the vibration test. Full article

(This article belongs to the Special Issue Solid-State Batteries)

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9 pages, 1163 KiB

Open AccessPerspective

Challenges for Modeling of Five-Axis Coordinate Measuring Systems

by Piotr Gąska, Adam Gąska^*

and Maciej Gruza

Laboratory of Coordinate Metrology, Cracow University of Technology, 31-155 Kraków, Poland

Appl. Sci. 2017, 7(8), 803; https://doi.org/10.3390/app7080803 - 7 Aug 2017

Cited by 10 | Viewed by 3716

Abstract

Modeling of various measuring systems used in coordinate metrology is a very relevant and current topic. Functional models of measuring systems are used in simulative methods as so called ‘virtual models’ and are used mainly for determination of measurement uncertainty and prediction of [...] Read more.

Modeling of various measuring systems used in coordinate metrology is a very relevant and current topic. Functional models of measuring systems are used in simulative methods as so called ‘virtual models’ and are used mainly for determination of measurement uncertainty and prediction of errors that may occur during the measurement. Virtual models have already been developed for coordinate measuring machines and articulated arm coordinate measuring machines and are currently under development for other, state-of-the-art measuring systems. They include Laser Tracking systems, optical coordinate measuring machines (CMMs) and five-axis measuring systems. The first step towards development of virtual model for the latter system was presented in a previous study by the authors. The simplified model for simulation and correction of probe head errors and its verification was proposed. This paper describes the challenges that must be faced before the final implementation of a fully functional virtual model of five-axis coordinate measuring systems. Full article

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15 pages, 7988 KiB

Open AccessArticle

A Compact and Multi-Stack Electromagnetic Bandgap Structure for Gigahertz Noise Suppression in Multilayer Printed Circuit Boards

by Myunghoi Kim^1,* and Seungyoung Ahn²

¹ Department of Electrical, Electronic, and Control Engineering, Institute for Information Technology Convergence, Hankyong National University, Anseong 17579, Korea

² The Cho Chun Shik Graduate School for Green Transportation, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea

Appl. Sci. 2017, 7(8), 804; https://doi.org/10.3390/app7080804 - 7 Aug 2017

Cited by 7 | Viewed by 4544

Abstract

In modern printed electronics, the performances of a circuit and a device are severely deteriorated by the electromagnetic noise in the gigahertz (GHz) frequency range, such as the simultaneous switching noise and ground bounce noise. A compact and multi-stack electromagnetic bandgap (CMS-EBG) structure [...] Read more.

In modern printed electronics, the performances of a circuit and a device are severely deteriorated by the electromagnetic noise in the gigahertz (GHz) frequency range, such as the simultaneous switching noise and ground bounce noise. A compact and multi-stack electromagnetic bandgap (CMS-EBG) structure is proposed to suppress the electromagnetic noise over the GHz frequency range with a short distance between a noise source and a victim on multilayer printed circuit boards (MPCBs). The original configuration of the stepped impedance resonators is presented to efficiently form multiple stacks of EBG cells. The noise suppression characteristics of the CMS-EBG structure are rigorously examined using Floquet-Bloch analysis. In the analysis, dispersion diagrams are extracted from an equivalent circuit model and a full-wave simulation model. It is experimentally verified that the CMS-EBG structure suppresses the resonant modes over the wideband frequency range with a short source-to-victim distance; thus, this structure substantially mitigates GHz electromagnetic noise in compact MPCBs. Full article

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

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11 pages, 2418 KiB

Open AccessArticle

Accelerated Sine-on-Random Vibration Test Method of Ground Vehicle Components over Conventional Single Mode Excitation

by Chan-Jung Kim

Department of Mechanical Design Engineering, Pukyong National University, Busan 48547, Korea

Appl. Sci. 2017, 7(8), 805; https://doi.org/10.3390/app7080805 - 7 Aug 2017

Cited by 12 | Viewed by 4650

Abstract

Automotive manufacturers typically assess the mechanical durability performance of ground vehicle components for vibration excitation using either random or harmonic spectral loading patterns, such as the loading patterns suggested in international standards (e.g., ISO-16750-3). Selection of the correct excitation profile is dependent on [...] Read more.

Automotive manufacturers typically assess the mechanical durability performance of ground vehicle components for vibration excitation using either random or harmonic spectral loading patterns, such as the loading patterns suggested in international standards (e.g., ISO-16750-3). Selection of the correct excitation profile is dependent on the service condition of the component of interest. However, in the instance where the vehicle component is exposed to both harmonic excitations and background noise, the severity of impact of the in-service environment cannot be satisfied via a single random or harmonic test alone. In this case, the optimal test strategy is to evaluate the vehicle component under a sine-on-random excitation. Within this study, a uniaxial excitation test was conducted for a notched simple specimen under three spectral loading cases (harmonic, random, and sine-on-random), and the test severity was determined based on two kinds of fatigue damage: the physical damage from measured strain and the calculated pseudo-damage from acceleration measurements, as indicated in ISO-16750-3. Based on this comparison of accumulated fatigue damage, the efficiency of the proposed sine-on random vibration was proved against conventional single spectral pattern test methods. Full article

(This article belongs to the Section Mechanical Engineering)

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14 pages, 4878 KiB

Open AccessArticle

Aging Characteristics of Rubber Modified Asphalts in Different Environmental Factors Combinations

by Peng Xiao¹, Jiahui Zheng¹, Aihong Kang^1,*, Lu Sun² and Yingqian Wang¹

¹ College of Civil Science and Engineering, Yangzhou University, Yangzhou 225009, Jiangsu, China

² Department of Civil Engineering, Catholic University of America, 620 Michigan Ave NE, Washington, DC 20064, USA

Appl. Sci. 2017, 7(8), 806; https://doi.org/10.3390/app7080806 - 7 Aug 2017

Cited by 21 | Viewed by 3653

Abstract

Two kinds of rubber modified asphalts were investigated and compared with virgin asphalt. In order to get closer to engineering practice, different combinations of four environmental factors were merged into the laboratory aging simulation. Subsequently, conventional property tests, including softening point, viscosity, creep [...] Read more.

Two kinds of rubber modified asphalts were investigated and compared with virgin asphalt. In order to get closer to engineering practice, different combinations of four environmental factors were merged into the laboratory aging simulation. Subsequently, conventional property tests, including softening point, viscosity, creep stiffness, creep rate, and fatigue cracking were conducted on asphalt samples. The performance difference of asphalt before and after aging was selected as an evaluation index for asphalt aging degree. The results indicate that two kinds of rubber modified asphalts show stronger resistant ability to temperature deformation and better resistance to traffic loading than virgin asphalt in all kinds of environmental factors combinations. Tests on chemical analyses were conducted to investigate the asphalt aging characteristics. The apparent morphology of rubber modified asphalts are described in detail under an environment scanning electron microscope (ESEM). The damage condition reflected in images reveals the aging degree caused by multiple environmental factors. Moreover, the thermogravimetric analysis (TG) confirms that three kinds of asphalts can maintain thermal stability in various environments. Additionally, new characteristic functional groups were not detected in the infrared (IR) spectra of rubber modified asphalts, which means they have stable antioxidant properties given that their oxidation degrees change slightly throughout the aging processes. Full article

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23 pages, 19938 KiB

Open AccessArticle

New Insights into the Short Pitch Corrugation Enigma Based on 3D-FE Coupled Dynamic Vehicle-Track Modeling of Frictional Rolling Contact

by Shaoguang Li, Zili Li^*, Alfredo Núñez

and Rolf Dollevoet

Section of Railway Engineering, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands

Appl. Sci. 2017, 7(8), 807; https://doi.org/10.3390/app7080807 - 7 Aug 2017

Cited by 75 | Viewed by 7666

Abstract

A three-dimensional (3D) finite element (FE) dynamic frictional rolling contact model is presented for the study of short pitch corrugation that considers direct and instantaneous coupling between the contact mechanics and the structural dynamics in a vehicle-track system. In this study, we examine [...] Read more.

A three-dimensional (3D) finite element (FE) dynamic frictional rolling contact model is presented for the study of short pitch corrugation that considers direct and instantaneous coupling between the contact mechanics and the structural dynamics in a vehicle-track system. In this study, we examine the system responses in terms of vibration modes, contact forces and the resulting wear with smooth rail and corrugated rail with progressively increasing amplitude to infer the conditions for consistent corrugation initiation and growth. Wear is assumed to be the damage mechanism, and short pitch corrugation is modeled using wavelengths from field observations of a Dutch railway. The contribution of this paper is a global perspective of the consistency conditions that govern the evolution of short pitch corrugation. The main insights are as follows: (1) the longitudinal vibration modes are probably dominant for short pitch corrugation initiation; (2) during short pitch corrugation evolution, the interaction and consistency between longitudinal and vertical modes should determine the development of short pitch corrugation, and once a certain severity is reached, vertical modes become dominant; and (3) in the case simulated in this paper, corrugation does not grow probably due to not only the different resulting main frequencies of the vertical and longitudinal contact forces, but also the inconsistency between the frequencies of the vertical and longitudinal vibration modes and the resulting wear. It is inferred that in the continuous process of initiation and growth of the corrugation, there should be a consistency between them, and this could be done by the control of certain track parameters. Full article

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18 pages, 4968 KiB

Open AccessArticle

Experimental Study on Effectiveness of a Prototype Seismic Isolation System Made of Polymeric Bearings

by Tomasz Falborski^*

and Robert Jankowski

Faculty of Civil and Environmental Engineering, Gdansk University of Technology, 11/12 Narutowicza St., 80-233 Gdansk, Poland

Appl. Sci. 2017, 7(8), 808; https://doi.org/10.3390/app7080808 - 8 Aug 2017

Cited by 51 | Viewed by 6657

Abstract

Seismic isolation is identified as one of the most popular and effective methods of protecting structures under strong dynamic excitations. Base isolators, such as Lead Rubber Bearings, High Damping Rubber Bearings, and Friction Pendulum Bearings, are widely used in practice in many earthquake-prone [...] Read more.

Seismic isolation is identified as one of the most popular and effective methods of protecting structures under strong dynamic excitations. Base isolators, such as Lead Rubber Bearings, High Damping Rubber Bearings, and Friction Pendulum Bearings, are widely used in practice in many earthquake-prone regions of the world to mitigate structural vibrations, and therefore minimize loss of life and property damage during seismic events. The present paper reports the results of the comprehensive experimental investigation designed to verify the effectiveness of a prototype base isolation system made of Polymeric Bearings in reducing structural vibrations. In order to construct seismic bearings considered in this study, a specially prepared polymeric material with improved damping properties was used. The dynamic behaviour of a single-storey and two-storey experimental model, both fixed-base and base-isolated, under a number of different ground motions, was extensively studied. The reduction in lateral response was measured by comparing the peak accelerations recorded at the top of the analyzed model structures with and without a base isolation system. The results of this research clearly demonstrate that the application of the prototype Polymeric Bearings leads to significant improvement in seismic response by reducing the lateral acceleration. Full article

(This article belongs to the Section Mechanical Engineering)

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18 pages, 1445 KiB

Open AccessArticle

ANCR—An Adaptive Network Coding Routing Scheme for WSNs with Different-Success-Rate Links

by Xiang Ji^1,†, Anwen Wang^1,†, Chunyu Li¹, Chun Ma¹, Yao Peng¹, Dajin Wang², Qingyi Hua^1,*

, Feng Chen¹ and Dingyi Fang¹

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

² Department of Computer Science, Montclair State University, Montclair, NJ 07043, USA

^† Co-first authors: These authors contributed equally to this work.

Appl. Sci. 2017, 7(8), 809; https://doi.org/10.3390/app7080809 - 8 Aug 2017

Cited by 4 | Viewed by 3953

Abstract

As the underlying infrastructure of the Internet of Things (IoT), wireless sensor networks (WSNs) have been widely used in many applications. Network coding is a technique in WSNs to combine multiple channels of data in one transmission, wherever possible, to save node’s energy [...] Read more.

As the underlying infrastructure of the Internet of Things (IoT), wireless sensor networks (WSNs) have been widely used in many applications. Network coding is a technique in WSNs to combine multiple channels of data in one transmission, wherever possible, to save node’s energy as well as increase the network throughput. So far most works on network coding are based on two assumptions to determine coding opportunities: (1) All the links in the network have the same transmission success rate; (2) Each link is bidirectional, and has the same transmission success rate on both ways. However, these assumptions may not be true in many actual WSNs—the wireless links among nodes are often subject to all kinds of disturbance, obstruction, etc., and may transmit with different success rates. This paper proposes a new routing strategy, named Adaptive Network Coding Routing (ANCR). ANCR firstly establishes a routing path with the traditional network coding routing (NCR), and then applies the neighborhood search algorithm to adaptively determine nodes’ coding opportunities based on the links’ transmission success rates, with the target of reducing the total number of transmission. The simulation results show that, in WSNs with different-success-rate links, ANCR can reduce the network delay by about 50%, and increase the network throughput by about 67%, compared with the traditional NCR. Full article

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15 pages, 1662 KiB

Open AccessArticle

Chlorine Tolerance and Inactivation of Escherichia coli recovered from Wastewater Treatment Plants in the Eastern Cape, South Africa

by Mojisola C. Owoseni^1,2,*, Ademola O. Olaniran³ and Anthony I. Okoh^1,2

¹ SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice 5700, South Africa

² Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice 5700, South Africa

³ Department of Microbiology, School of Life Sciences, University of Kwazulu-Natal, Private Bag X54001, Durban 4000, South Africa

Appl. Sci. 2017, 7(8), 810; https://doi.org/10.3390/app7080810 - 8 Aug 2017

Cited by 40 | Viewed by 12837

Abstract

This study investigated the survival of Escherichia coli (E. coli) recovered from secondary effluents of two wastewater treatment plants in the Eastern Cape Province, South Africa, in the presence of different chlorine concentrations. The bacterial survival, chlorine lethal dose and inactivation [...] Read more.

This study investigated the survival of Escherichia coli (E. coli) recovered from secondary effluents of two wastewater treatment plants in the Eastern Cape Province, South Africa, in the presence of different chlorine concentrations. The bacterial survival, chlorine lethal dose and inactivation kinetics at lethal doses were examined. The bacterial isolates were identified by 16S rRNA gene sequencing. Comparison of the nucleotide sequences of 16S rRNA gene of bacteria with known taxa in the GenBank revealed the bacterial isolates to belong to Escherichia coli. At the recommended free chlorine of 0.5 mg/L, reduction of E. coli isolates (n = 20) initial bacterial concentration of 8.35–8.75 log was within a range of 3.88–6.0 log at chlorine residuals of 0.14–0.44 mg/L after 30 min. At higher doses, a marked reduction (p < 0.05) in the viability of E. coli isolates was achieved with a greater than 7.3 log inactivation of the bacterial population. Inactivation kinetics revealed a high rate of bacterial kill over time (R² > 0.9) at chlorine dose of 1.5 mg/L. This study indicates poor removal of bacteria at free chlorine at 0.5 mg/L and a greater efficacy of 1.5 mg/L in checking E. coli tolerance. Full article

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16 pages, 1686 KiB

Open AccessArticle

Experimental Evaluation of Thermal Performance and Durability of Thermally-Enhanced Concretes

by Yong-Wook Jeong¹

, Tae-Hoon Koh², Kwang-Soo Youm³ and Jiho Moon^4,*

¹ Department of Architecture, Sejong University, Seoul 05006, Korea

² New Transportation Research Center, Korea Railroad Research Institute, Uiwang-Si, Gyeonggi-do 16105, Korea

³ Infra Structure Team, Technical Division, GS E & C, Grand Seoul, 33 Jong-ro, Jongno-gu, Seoul 03159, Korea

⁴ Department of Civil Engineering, Kangwon National University, Chuncheon-si, Gangwon-do 24341, Korea

Appl. Sci. 2017, 7(8), 811; https://doi.org/10.3390/app7080811 - 8 Aug 2017

Cited by 14 | Viewed by 4433

Abstract

The thermal performance and durability of the thermally-enhanced concrete with various insulating materials were evaluated through a series of tests. Three types of insulating materials—diatomite powder, hollow micro-spheres, and a micro-foam agent—were used for both normalweight aggregate concrete (NWAC) and lightweight aggregate concrete [...] Read more.

The thermal performance and durability of the thermally-enhanced concrete with various insulating materials were evaluated through a series of tests. Three types of insulating materials—diatomite powder, hollow micro-spheres, and a micro-foam agent—were used for both normalweight aggregate concrete (NWAC) and lightweight aggregate concrete (LWAC). The thermal conductivity was measured by two different test methods: quick thermal conductivity meter (QTM) and guarded hot wire (GHW) methods. Then, the results were compared with each other. All insulating materials used in this study proved their ability to reduce the thermal conductivity. Additionally, it can be found that the trend of a decrease in air-dry density is similar to that of thermal conductivity of thermally-enhanced concrete. Additional thermal transmission tests with seven large-scale specimens were conducted by using the calibrated hot box (CHB). However, from this tests, it was seen that thermal transmission reduction for tested specimens were not large compared to the thermal conductivity reduction measured by QTM and GHW, due to multiple heat transfer. To examine the durability of thermally-enhanced concretes, accelerated carbonation and freeze-thaw cycle tests were conducted. From the results, it can be found that the thermally-enhanced concrete shows good freeze-thaw resistance. However, the carbonation rates of the concretes increased rapidly and additional methods to improve the carbonation resistance should be considered. Full article

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

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16 pages, 1909 KiB

Open AccessFeature PaperArticle

Time Behaviour of Helium Atmospheric Pressure Plasma Jet Electrical and Optical Parameters

by Ioana Cristina Gerber¹, Ilarion Mihaila^2,*

, Dennis Hein¹, Andrei Vasile Nastuta^1,†

, Roxana Jijie¹, Valentin Pohoata¹ and Ionut Topala^1,*

¹ Iasi Plasma Advanced Research Center (IPARC), Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bd. Carol I No. 11, 700506 Iasi, Romania

² Integrated Center of Environmental Science Studies in the North-Eastern Development Region (CERNESIM), Alexandru Ioan Cuza University of Iasi, Bd. Carol I No. 11, 700506 Iasi, Romania

^† Current address: Grigore T. Popa University of Medicine and Pharmacy Iasi, Faculty of Medical Bioengineering, Biomedical Science Department, Str. M. Kogalniceanu no. 9–13, 700454 Iasi, Romania.

Appl. Sci. 2017, 7(8), 812; https://doi.org/10.3390/app7080812 - 9 Aug 2017

Cited by 16 | Viewed by 6640

Abstract

Low temperature plasma jets gained increased interest in the last years as a potential device in many life science applications, including here human or veterinary medicine. Standardisation of plasma sources and biological protocols are necessary for quality assurance reasons, due to the fact [...] Read more.

Low temperature plasma jets gained increased interest in the last years as a potential device in many life science applications, including here human or veterinary medicine. Standardisation of plasma sources and biological protocols are necessary for quality assurance reasons, due to the fact that this type of atmospheric pressure plasma source is available in multiple configurations and their operational parameters span also on a broad range of items, such as all characteristics of high voltage pulses used for gas breakdown, geometrical characteristics, gas feed composition and conductive or biological target characteristics. In this paper we present results related to electrical, optical and molecular beam mass spectrometry diagnosis of a helium plasma jet, emphasising the influence of various operational parameters of the high voltage pulses on plasma jet properties. Discussion on physical parameters that influence the biological response is included, together with important results on plasma sources statistical behaviour until reaching a quasi-stationary working regime. The warm-up period of the plasma jet, specific to many other plasma sources, must be precisely known and specified whenever the plasma jets are used as a tool for life science applications. Full article

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21 pages, 2819 KiB

Open AccessArticle

Optimal Control of Wastewater Treatment Plants Using Economic-Oriented Model Predictive Dynamic Strategies

by Silvana Revollar^1,*, Pastora Vega¹, Ramón Vilanova²

and Mario Francisco¹

¹ Department of Computing and automation, University of Salamanca, 37008 Salamanca, Spain

² Department of Telecommunications and Systems Engineering School of Engineering, Universitat Autònoma de Barcelona, 08193 Catalonia, Spain

Appl. Sci. 2017, 7(8), 813; https://doi.org/10.3390/app7080813 - 9 Aug 2017

Cited by 75 | Viewed by 7060

Abstract

This paper addresses the implementation of economic-oriented model predictive controllers for the dynamic real-time optimization of the operation of wastewater treatment plants (WWTP). Both the economic-optimizing controller (pure-EMPC) and the economic-oriented tracking controller (Hybrid-EMPC, or HEMPC) formulations are validated in the benchmark simulation [...] Read more.

This paper addresses the implementation of economic-oriented model predictive controllers for the dynamic real-time optimization of the operation of wastewater treatment plants (WWTP). Both the economic-optimizing controller (pure-EMPC) and the economic-oriented tracking controller (Hybrid-EMPC, or HEMPC) formulations are validated in the benchmark simulation model (BSM1) platform that represents the behavior of a characteristic activated sludge process. The objective of the controllers is to ensure the appropriate operation of the plant, while minimizing the energy consumption and the fines for violations of the limits of the ammonia concentration in the effluent along the full operating period. A non-linear reduced model of the activated sludge process is used for predictions to obtain a reasonable computing effort, and techniques to deal with model-plant mismatch are incorporated in the controller algorithm. Different designs and structures are compared in terms of process performance and energy costs, which show that the implementation of the proposed control technique can produce significant economic and environmental benefits, depending on the desired performance criteria. Full article

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13 pages, 2268 KiB

Open AccessArticle

Modeling Non-Equilibrium Dynamics and Saturable Absorption Induced by Free Electron Laser Radiation

by Keisuke Hatada^*,†

and Andrea Di Cicco

¹ Physics Division, School of Science and Technology, University of Camerino, I-62032 Camerino (MC), Italy

^† Current address: Department Chemie, Ludwig-Maximilians-Universität München, 81377 München, Germany

Appl. Sci. 2017, 7(8), 814; https://doi.org/10.3390/app7080814 - 9 Aug 2017

Cited by 5 | Viewed by 4246

Abstract

Currently available X-ray and extreme ultraviolet free electron laser (FEL) sources provide intense ultrashort photon pulses. Those sources open new exciting perspectives for experimental studies of ultrafast non-equilibrium processes at the nanoscale in condensed matter. Theoretical approaches and computer simulations are being developed [...] Read more.

Currently available X-ray and extreme ultraviolet free electron laser (FEL) sources provide intense ultrashort photon pulses. Those sources open new exciting perspectives for experimental studies of ultrafast non-equilibrium processes at the nanoscale in condensed matter. Theoretical approaches and computer simulations are being developed to understand the complicated dynamical processes associated with the interaction of FEL pulses with matter. In this work, we present the results of the application of a simplified three-channel model to the non-equilibrium dynamics of ultrathin aluminum films excited by FEL radiation at 33.3, 37 and 92 eV photon energy. The model includes semi-classical rate equations coupled with the equation of propagation of the photon wave packets. X-ray transmission measurements are found to be in agreement with present simulations, which are also able to shed light on temporal dynamics (in the fs range) in nano-sized Al films strongly interacting with the photon pulse. We also expanded our non-linear model, explicitly including the two-photon absorption cross-section and the effect of including electron heating for reproducing transmission measurements. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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15 pages, 11605 KiB

Open AccessArticle

Laser Irradiation Responses of a Single-Crystal Diamond Produced by Different Crystal Growth Methods

by Nozomi Takayama and Jiwang Yan^*

Department of Mechanical Engineering, Keio University, Hiyoshi 3-14-1 Kohoku, Yokohama, Kanagawa 223-8522, Japan

Appl. Sci. 2017, 7(8), 815; https://doi.org/10.3390/app7080815 - 9 Aug 2017

Cited by 20 | Viewed by 5382

Abstract

Responses of two types of single-crystal diamonds, prepared by chemical vapour deposition (CVD) and high pressure high temperature synthesis (HPHT) methods, respectively, to a nanosecond pulsed neodymium-doped yttrium aluminium garnet (Nd:YAG) laser were investigated and compared. It was found that due to the [...] Read more.

Responses of two types of single-crystal diamonds, prepared by chemical vapour deposition (CVD) and high pressure high temperature synthesis (HPHT) methods, respectively, to a nanosecond pulsed neodymium-doped yttrium aluminium garnet (Nd:YAG) laser were investigated and compared. It was found that due to the difference in the transmission rate and refractive index, the laser-induced surface/subsurface features of the two types of samples were distinctly different. For the CVD sample, destructive interference takes place on the upper surface, leading to direct ablation of smooth grooves with deposition of graphite. For the HPHT sample, however, laser-induced grooves were formed on the reverse side of the irradiation surface (namely, the lower surface) at certain laser fluences due to the constructive interference phenomenon of the laser and the high refractive index of the material. The reverse-side irradiation resulted in the formation of deep and sharp grooves with rough bottoms and insignificant deposition of graphite on the area surrounding the groove. The machining thresholds for the upper and lower surfaces of both types of diamonds were experimentally obtained and theoretically verified. The findings of this study provide important process criteria for laser machining of different kinds of diamonds. The reverse-side irradiation method enables efficient machining of deep grooves in diamonds using a lower power laser. Full article

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

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19 pages, 11094 KiB

Open AccessArticle

Analysis of the Energy Efficiency of a Pneumatic Booster Regulator with Energy Recovery

by Fan Yang^1,2,*

, Kotaro Tadano², Gangyan Li^1,* and Toshiharu Kagawa²

¹ School of Mechanical and Electronic Engineering, Wuhan University of Technology, Wuhan 430070, China

² Future Interdisciplinary Research of Science and Technology, Tokyo Institute of Technology, Yokohama 226-8503, Japan

Appl. Sci. 2017, 7(8), 816; https://doi.org/10.3390/app7080816 - 9 Aug 2017

Cited by 22 | Viewed by 6883

Abstract

Pneumatic booster regulators (PBR) are in great demand in modern pneumatic systems for their energy-saving abilities. A new booster regulator with energy recovery (VBA-R) was proposed, and its energy efficiency was investigated by introducing the concept of air power. On the basis of [...] Read more.

Pneumatic booster regulators (PBR) are in great demand in modern pneumatic systems for their energy-saving abilities. A new booster regulator with energy recovery (VBA-R) was proposed, and its energy efficiency was investigated by introducing the concept of air power. On the basis of quality-alterable gas thermodynamics, an energy efficiency assessment and pressure response model for VBA-R was proposed. First, a model was solved using MATLAB/Simulink software, and an alternative experiment was designed to verify the mathematical model and performance improvement. The results showed that the simulation was consistent with the experiment. We also can conclude that, first of all, the energy efficiency decreases with the increasing of supply pressure and flow-rate consumption; a VBA-R has the highest efficiency when its diameter ratio is closest to 1.3. Finally, a recovery chamber helped to improve the performance of the VBA-R, which included a boost ratio improvement of 15–25% and an efficiency improvement of 5–10% compared with a conventional VBA booster regulator. This research lays the foundation for optimism regarding the proposed booster regulator. Full article

(This article belongs to the Special Issue Power Transmission and Control in Power and Vehicle Machineries)

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18 pages, 2459 KiB

Open AccessArticle

An Efficient Network Coding-Based Fault-Tolerant Mechanism in WBAN for Smart Healthcare Monitoring Systems

by Yuhuai Peng^1,2, Xiaojie Wang^3,*, Lei Guo^1,2, Yichun Wang³ and Qingxu Deng^1,2,*

¹ Key Laboratory of Medical Image Computing of Ministry of Education, Northeastern University, Shenyang 110819, China

² School of Computer Science and Engineering, Northeastern University, Shenyang 110819, China

³ School of Software, Dalian University of Technology, Dalian 116620, China

Appl. Sci. 2017, 7(8), 817; https://doi.org/10.3390/app7080817 - 10 Aug 2017

Cited by 42 | Viewed by 7760

Abstract

As a key technology in smart healthcare monitoring systems, wireless body area networks (WBANs) can pre-embed sensors and sinks on body surface or inside bodies for collecting different vital signs parameters, such as human Electrocardiograph (ECG), Electroencephalograph (EEG), Electromyogram (EMG), body temperature, blood [...] Read more.

As a key technology in smart healthcare monitoring systems, wireless body area networks (WBANs) can pre-embed sensors and sinks on body surface or inside bodies for collecting different vital signs parameters, such as human Electrocardiograph (ECG), Electroencephalograph (EEG), Electromyogram (EMG), body temperature, blood pressure, blood sugar, blood oxygen, etc. Using real-time online healthcare, patients can be tracked and monitored in normal or emergency conditions at their homes, hospital rooms, and in Intensive Care Units (ICUs). In particular, the reliability and effectiveness of the packets transmission will be directly related to the timely rescue of critically ill patients with life-threatening injuries. However, traditional fault-tolerant schemes either have the deficiency of underutilised resources or react too slowly to failures. In future healthcare systems, the medical Internet of Things (IoT) for real-time monitoring can integrate sensor networks, cloud computing, and big data techniques to address these problems. It can collect and send patient’s vital parameter signal and safety monitoring information to intelligent terminals and enhance transmission reliability and efficiency. Therefore, this paper presents a design in healthcare monitoring systems for a proactive reliable data transmission mechanism with resilience requirements in a many-to-one stream model. This Network Coding-based Fault-tolerant Mechanism (NCFM) first proposes a greedy grouping algorithm to divide the topology into small logical units; it then constructs a spanning tree based on random linear network coding to generate linearly independent coding combinations. Numerical results indicate that this transmission scheme works better than traditional methods in reducing the probability of packet loss, the resource redundant rate, and average delay, and can increase the effective throughput rate. Full article

(This article belongs to the Special Issue Smart Healthcare)

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15 pages, 3635 KiB

Open AccessArticle

Experimental Study on Mechanical Behavior of Shear Connectors of Square Concrete Filled Steel Tube

by Qiyun Qiao¹, Wenwen Zhang¹, Zhiwei Qian^2,*

, Wanlin Cao¹ and Wenchao Liu¹

¹ College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, China

² Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft 2628 CN, The Netherlands

Appl. Sci. 2017, 7(8), 818; https://doi.org/10.3390/app7080818 - 10 Aug 2017

Cited by 16 | Viewed by 7382

Abstract

In order to quantitatively evaluate the shear-bearing capacity of shear connectors of square concrete filled steel tube (CFST), push-out tests on 14 square CFSTs with shear connectors have been carried out. Among the 14 CFSTs, there are 13 specimens with steel plate connectors [...] Read more.

In order to quantitatively evaluate the shear-bearing capacity of shear connectors of square concrete filled steel tube (CFST), push-out tests on 14 square CFSTs with shear connectors have been carried out. Among the 14 CFSTs, there are 13 specimens with steel plate connectors and one specimen with steel bar connectors. The following factors are investigated to figure out their influences on the performance of CFSTs, which are the width to thickness ratio of steel tube, thickness of steel plate, length of steel plate, strength of concrete, welding condition of steel plate, number of steel plate layer and interlayer spacing. The test results show that the ultimate bearing capacity and the elastic stiffness increase with decreasing width to thickness ratio of the steel tube, and increasing thickness and length of the steel plate. With increasing concrete strength, the ultimate bearing capacity also increases. However, the welding condition has no effect on the ultimate bearing capacity. The ultimate bearing capacity of the CFST with double-layer steel plate is greater than that with single-layer steel plate. The ultimate bearing capacity of steel bar type shear connector is 87% greater than that of the steel plate type shear connector, and the steel bar specimen shows good ductility. A formula for calculating the shear-bearing capacity of shear connectors has been developed, and the calculated shear-bearing capacities are in good agreement with the test data. Full article

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12 pages, 706 KiB

Open AccessArticle

Size Characterisation Method and Detection Enhancement of Plasmonic Nanoparticles in a Pump–Probe System

by Rafael Fuentes-Domínguez^1,*

, Richard J. Smith¹

, Fernando Pérez-Cota¹, Leonel Marques¹, Ovidio Peña-Rodríguez²

and Matt Clark¹

¹ Optics and Photonics Group, University of Nottingham, University Park, Nottingham NG7 2RD, UK

² Instituto de Fusión Nuclear, Universidad Politécnica de Madrid, C/ José Gutiérrez Abascal 2, E-28006 Madrid, Spain

Appl. Sci. 2017, 7(8), 819; https://doi.org/10.3390/app7080819 - 10 Aug 2017

Cited by 5 | Viewed by 4550

Abstract

The optical resonance of metal nanoparticles can be used to enhance the generation and detection of their main vibrational mode. In this work, we show that this method allows the accurate characterisation of the particle’s size because the vibrational frequency of plasmonic nanoparticles [...] Read more.

The optical resonance of metal nanoparticles can be used to enhance the generation and detection of their main vibrational mode. In this work, we show that this method allows the accurate characterisation of the particle’s size because the vibrational frequency of plasmonic nanoparticles only depends on their mechanical properties. Moreover, by a careful selection of the particle size and/or probe laser wavelength, the detected signal can be increased by a large factor (∼9 for the particles used in this work) under the same illumination conditions. Finally, we show experimentally that particles of different sizes inside the point spread function can be observed due to the differences in their vibrational states, which could provide a feasible route to super-resolution. Full article

(This article belongs to the Special Issue Laser Interaction with Plasmonic Nanostructures)

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9 pages, 3029 KiB

Open AccessArticle

High Conductivity and Adhesion of Cu-Cr-Zr Alloy for TFT Gate Electrode

by Junbiao Peng¹, Kuankuan Lu¹, Shiben Hu¹

, Zhiqiang Fang¹

, Honglong Ning^1,*

, Jinglin Wei¹, Zhennan Zhu¹, Yicong Zhou¹, Lei Wang¹, Rihui Yao^1,*

and Xubing Lu²

¹ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China

² Institute for Advanced Materials and Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006, China

Appl. Sci. 2017, 7(8), 820; https://doi.org/10.3390/app7080820 - 10 Aug 2017

Cited by 8 | Viewed by 5969

Abstract

The characteristics of Cu alloy (0.3 wt. % Cr, 0.2 wt. % Zr) thin film deposited by direct current (DC) magnetron sputtering deposition were investigated. The conductivity and adhesion of the Cu-0.3%Cr-0.2%Zr films were optimized by increasing the sputter power to 150 W [...] Read more.

The characteristics of Cu alloy (0.3 wt. % Cr, 0.2 wt. % Zr) thin film deposited by direct current (DC) magnetron sputtering deposition were investigated. The conductivity and adhesion of the Cu-0.3%Cr-0.2%Zr films were optimized by increasing the sputter power to 150 W and reducing the sputter pressure to 2 mTorr. With an annealing process (at 300 °C for 1 h in argon ambient atmosphere), the resistivity of the alloy film decreased from 4.80 to 2.96 μΩ·cm, and the adhesion classification increased from 2B to 4B on glass substrate. X-ray photoelectron spectroscopy (XPS) analysis showed that Cr aggregated toward the surface of the film and formed a self-protection layer in the annealing process. Transmission electron microscopy (TEM) indicated the aggregation and migration of Cr in the annealing process. A further X-ray diffraction (XRD) analysis showed that Cu₂O appeared when the annealing temperature reached above 350 °C, which accounts for the increase of the resistivity. Based on Al₂O₃ and SiO₂ substrate surfaces, the Cu-0.3%Cr-0.2%Zr film also showed high conductivity and adhesion, which has a potential in the application of Cu gate electrodes for thin film transistor (TFT). Full article

(This article belongs to the Special Issue Thin-Film Transistor)

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18 pages, 3443 KiB

Open AccessArticle

Enhancing Interpretation of Ambiguous Voice Instructions based on the Environment and the User’s Intention for Improved Human-Friendly Robot Navigation

by M. A. Viraj J. Muthugala^*

, P. H. D. Arjuna S. Srimal

and A. G. Buddhika P. Jayasekara

Robotics and Control Laboratory, Department of Electrical Engineering, University of Moratuwa, Moratuwa 10400, Sri Lanka

Appl. Sci. 2017, 7(8), 821; https://doi.org/10.3390/app7080821 - 10 Aug 2017

Cited by 10 | Viewed by 4730

Abstract

Human-friendly interactive features are preferred for domestic service robots. Humans prefer to use verbal communication in order to convey instructions to peers. Those voice instructions often include uncertain terms such as “little” and “far”. Therefore, the ability to quantify such information is mandatory [...] Read more.

Human-friendly interactive features are preferred for domestic service robots. Humans prefer to use verbal communication in order to convey instructions to peers. Those voice instructions often include uncertain terms such as “little” and “far”. Therefore, the ability to quantify such information is mandatory for human-friendly service robots. The meaning of such voice instructions depends on the environment and the intention of the user. Therefore, this paper proposes a method in order to interpret the ambiguities in user instructions based on the environment and the intention of the user. The actual intention of the user is identified by analyzing the pointing gestures accompanied with the voice instructions since pointing gestures can be used in order to express the intention of the user. A module called the motion intention switcher (MIS) has been introduced in order to switch the intention of the robot based on the arrangement of the environment and the point referred by the gesture. Experiments have been carried out in an artificially-created domestic environment. According to the experimental results, the behavior of the MIS is effective in identifying the actual intention of the user and switching the intention of the robot. Moreover, the proposed concept is capable of enhancing the uncertain information evaluation ability of robots. Full article

(This article belongs to the Special Issue Social Robotics)

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7 pages, 756 KiB

Open AccessArticle

Picosecond Photoacoustic Metrology of SiO₂ and LiNbO₃ Layer Systems Used for High Frequency Surface-Acoustic-Wave Filters

by Delia Brick^1,*

, Erkan Emre¹, Martin Grossmann¹, Thomas Dekorsy^1,2 and Mike Hettich¹

¹ Department of Physics, University of Konstanz, 78464 Konstanz, Germany

² Institute of Technical Physics, German Aerospace Center, Pfaffenwaldring 38-40, 70569 Stuttgart, Germany

Appl. Sci. 2017, 7(8), 822; https://doi.org/10.3390/app7080822 - 10 Aug 2017

Cited by 13 | Viewed by 4768

Abstract

Many applications of thin films necessitate detailed information about their thicknesses and sound velocities. Here, we study SiO₂/LiNbO₃ layer systems by picosecond photoacoustic metrology and measure the sound velocities of the respective layers and the film thickness of SiO₂ [...] Read more.

Many applications of thin films necessitate detailed information about their thicknesses and sound velocities. Here, we study SiO₂/LiNbO₃ layer systems by picosecond photoacoustic metrology and measure the sound velocities of the respective layers and the film thickness of SiO₂, which pose crucial information for the fabrication of surface-acoustic-wave filters for communication technology. Additionally, we utilize the birefringence and the accompanying change in the detection sensitivity of coherent acoustic phonons in the LiNbO₃ layer to infer information about the LiNbO₃ orientation and the layer interface. Full article

(This article belongs to the Section Acoustics and Vibrations)

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21 pages, 3146 KiB

Open AccessArticle

Pollutant Recognition Based on Supervised Machine Learning for Indoor Air Quality Monitoring Systems

by Shaharil Mad Saad^1,*

, Allan Melvin Andrew²

, Ali Yeon Md Shakaff³, Mohd Azuwan Mat Dzahir¹, Mohamed Hussein¹, Maziah Mohamad¹ and Zair Asrar Ahmad¹

¹ Faculty of Mechanical Engineering, Universiti Teknologi Malaysia (UTM), Johor Bahru 81310, Malaysia

² Center for Diploma Studies (CDS), Universiti Malaysia Perlis (UniMAP), Kampus UniCITI Alam, Chuchuh, Padang Besar 02100, Malaysia

³ Center of Excellence for Advanced Sensor Technology (CEASTech), Universiti Malaysia Perlis (UniMAP), Taman Muhibbah, Jejawi, Arau 02600, Malaysia

Appl. Sci. 2017, 7(8), 823; https://doi.org/10.3390/app7080823 - 11 Aug 2017

Cited by 25 | Viewed by 7131

Abstract

Indoor air may be polluted by various types of pollutants which may come from cleaning products, construction activities, perfumes, cigarette smoke, water-damaged building materials and outdoor pollutants. Although these gases are usually safe for humans, they could be hazardous if their amount exceeded [...] Read more.

Indoor air may be polluted by various types of pollutants which may come from cleaning products, construction activities, perfumes, cigarette smoke, water-damaged building materials and outdoor pollutants. Although these gases are usually safe for humans, they could be hazardous if their amount exceeded certain limits of exposure for human health. A sophisticated indoor air quality (IAQ) monitoring system which could classify the specific type of pollutants is very helpful. This study proposes an enhanced indoor air quality monitoring system (IAQMS) which could recognize the pollutants by utilizing supervised machine learning algorithms: multilayer perceptron (MLP), K-nearest neighbour (KNN) and linear discrimination analysis (LDA). Five sources of indoor air pollutants have been tested: ambient air, combustion activity, presence of chemicals, presence of fragrances and presence of food and beverages. The results showed that the three algorithms successfully classify the five sources of indoor air pollution (IAP) with a classification rate of up to 100 percent. An MLP classifier with a model structure of 9-3-5 has been chosen to be embedded into the IAQMS. The system has also been tested with all sources of IAP presented together. The result shows that the system is able to classify when single and two mixed sources are presented together. However, when more than two sources of IAP are presented at the same period, the system will classify the sources as ‘unknown’, because the system cannot recognize the input of the new pattern. Full article

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14 pages, 1770 KiB

Open AccessArticle

Effect of Prestress Levels and Jacking Methods on Friction Losses in Curved Prestressed Tendons

by Sungnam Hong

College of Engineering, Sungkyunkwan University, Natural Sciences Campus, (16419) 2066 Seobu-Ro, Jangan-Gu, Suwon-Si, Gyeonggi-Do, Korea

Appl. Sci. 2017, 7(8), 824; https://doi.org/10.3390/app7080824 - 11 Aug 2017

Cited by 9 | Viewed by 10087

Abstract

The effects of prestressing methods and prestress levels on the friction losses of prestressed tendons were evaluated in this study. Two full-scale prestressed concrete girders were fabricated and used for the friction loss experiment. The prestress level was varied from 13% to 45% [...] Read more.

The effects of prestressing methods and prestress levels on the friction losses of prestressed tendons were evaluated in this study. Two full-scale prestressed concrete girders were fabricated and used for the friction loss experiment. The prestress level was varied from 13% to 45% of the ultimate tensile strength of the prestressing tendon, and prestressing was performed by jacking one or both ends. The test results indicated that the actual friction loss measured at low prestress levels was up to 4.3 times higher than the theoretical friction loss. As the prestress level increased, the difference between the measured and theoretical friction losses gradually decreased, and the two eventually converged. On average, the ratio of the prestress force at the jacking end to the prestress force measured at midspan was 85.4% with jacking at both ends, and 81.1% with jacking at one end. Full article

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17 pages, 859 KiB

Open AccessArticle

Energy Prediction of Access Points in Wi-Fi Networks According to Users’ Behaviour

by David Rodriguez-Lozano¹, Juan A. Gomez-Pulido^1,*

, Jose M. Lanza-Gutierrez²

, Arturo Duran-Dominguez¹, Broderick Crawford³

and Ricardo Soto³

¹ Escuela Polítécnica, Universidad de Extremadura, 10003 Cáceres, Spain

² Centro de Electrónica Industrial, Universidad Politécnica de Madrid, 28006 Madrid, Spain

³ Escuela de Ingeniería Informática, Pontificia Universidad Católica de Valparaíso, 2362807 Valparaíso, Chile

Appl. Sci. 2017, 7(8), 825; https://doi.org/10.3390/app7080825 - 11 Aug 2017

Viewed by 3509

Abstract

Some maintenance tasks in Wi-Fi networks may involve removing an access point due to several reasons. As a result, the new infrastructure registers a different number of roamings in the access points according to the users’ behaviour, with a certain energy impact added [...] Read more.

Some maintenance tasks in Wi-Fi networks may involve removing an access point due to several reasons. As a result, the new infrastructure registers a different number of roamings in the access points according to the users’ behaviour, with a certain energy impact added to the consumption caused by the own operations of the devices. This energy effect should be understood in order to tackle the measures aimed at planning the infrastructure deployment. In this work, we propose a methodology to predict the energy consumption in the access points of a Wi-Fi network when we remove a particular device, based on a twofold support. We predict the number of roamings following a method previously validated; on the other hand, we assess the relationship between roamings and energy in the full infrastructure, using the data collected from a high number of network users during a given time in order to reflect the users’ behaviour with the maximum accuracy. From this knowledge, we can infer the energy prediction for a different environment where the roamings are predicted using techniques based on recommender systems and machine learning. Full article

(This article belongs to the Special Issue Green Wireless Networks)

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19 pages, 4597 KiB

Open AccessArticle

Optimized Deep Neural Networks for Real-Time Object Classification on Embedded GPUs

by Syed Tahir Hussain Rizvi^1,*

, Gianpiero Cabodi¹

and Gianluca Francini²

¹ Dipartimento di Automatica e Informatica (DAUIN), Politecnico di Torino, 10129 Turin, Italy

² Joint Open Lab, Telecom Italia Mobile (TIM), 10129 Turin, Italy

Appl. Sci. 2017, 7(8), 826; https://doi.org/10.3390/app7080826 - 11 Aug 2017

Cited by 10 | Viewed by 4191

Abstract

Convolution is the most computationally intensive task of the Convolutional Neural Network (CNN). It requires a lot of memory storage and computational power. There are different approaches to compute the solution of convolution and reduce its computational complexity. In this paper, a matrix [...] Read more.

Convolution is the most computationally intensive task of the Convolutional Neural Network (CNN). It requires a lot of memory storage and computational power. There are different approaches to compute the solution of convolution and reduce its computational complexity. In this paper, a matrix multiplication-based convolution (ConvMM) approach is fully parallelized using concurrent resources of GPU (Graphics Processing Unit) and optimized, considerably improving the performance of the image classifiers and making them applicable to real-time embedded applications. The flow of this CUDA (Compute Unified Device Architecture)-based scheme is optimized using unified memory and hardware-dependent acceleration of matrix multiplication. Proposed flow is evaluated on two different embedded platforms: first on an Nvidia Jetson TX1 embedded board and then on a Tegra K1 GPU of an Nvidia Shield K1 Tablet. The performance of this optimized and accelerated convolutional layer is compared with its sequential and heterogeneous versions. Results show that the proposed scheme significantly improves the overall results including energy efficiency, storage requirement and inference performance. In particular, the proposed scheme on embedded GPUs is hundreds of times faster than the sequential version and delivers tens of times higher performance than the heterogeneous approach. Full article

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18 pages, 7059 KiB

Open AccessArticle

A Power Processing Circuit for Indoor Wi-Fi Energy Harvesting for Ultra-Low Power Wireless Sensors

by Ermeey Abd Kadir^1,* and Aiguo Patrick Hu^2,*

¹ Faculty of Electrical Engineering, Universiti Teknologi Mara, Shah Alam 40450, Malaysia

² Electrical and Computer Engineering Department, the University of Auckland, Auckland 1010, New Zealand

Appl. Sci. 2017, 7(8), 827; https://doi.org/10.3390/app7080827 - 11 Aug 2017

Cited by 8 | Viewed by 5178

Abstract

This article proposes a complete power processing circuit for an indoor 2.45 GHz Wi-Fi energy harvesting system. The proposed power processing circuit works by using power harvested from indoor Wi-Fi transmitters. The overall system of this work is simplified as an equivalent circuit [...] Read more.

This article proposes a complete power processing circuit for an indoor 2.45 GHz Wi-Fi energy harvesting system. The proposed power processing circuit works by using power harvested from indoor Wi-Fi transmitters. The overall system of this work is simplified as an equivalent circuit and analyzed mathematically. A two-port network is analyzed in formulating the relevant equations of the equivalent circuit. The importance of matching the impedance of a harvesting antenna to the rectifier circuit is highlighted by using simulation analysis, and it is shown that the impedance matching for both components has satisfied the conditions for a high sensitivity circuit and radio frequency-to-direct current (RF-to-DC) power conversion. Actual experiments showed that the proposed power processing circuit could operate with an incident power as low as −50 dBm. It has been found that the proposed harvesting system stored 0.11 J in a 200 mF supercapacitor as the storage device in 20 hours of the experimentation periods. Moreover, actual results for the overall energy harvesting system is compared with previous research, and it has been found that the proposed system has advantages over the listed works. Full article

(This article belongs to the Special Issue Smart Home and Energy Management Systems)

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15 pages, 4835 KiB

Open AccessArticle

Preparation, Physicochemical Properties, and Long-Term Performance of Photocatalytic Ceramsite Sand in Cementitious Materials

by Du Zhao¹, Fazhou Wang¹, Peng Liu^1,2, Lu Yang¹, Shuguang Hu¹ and Wenqin Zhang^1,*

¹ State Key Laboratory of Silicate Materials for Architecture, Wuhan University of Technology, Wuhan 430070, China

² School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, China

Appl. Sci. 2017, 7(8), 828; https://doi.org/10.3390/app7080828 - 11 Aug 2017

Cited by 14 | Viewed by 4378

Abstract

Incorporation of TiO₂ into cementitious materials is an important technology in the field of photocatalytic pollution mitigation; however, the photocatalytic activity of TiO₂ is limited by specific surface area, poor gas diffusion and light transmission performance of cementitious materials. In this [...] Read more.

Incorporation of TiO₂ into cementitious materials is an important technology in the field of photocatalytic pollution mitigation; however, the photocatalytic activity of TiO₂ is limited by specific surface area, poor gas diffusion and light transmission performance of cementitious materials. In this study, a novel photocatalytic lightweight aggregate—photocatalytic ceramsite sand (PCS) was synthesized by loading TiO₂ on activated porous ceramsite sand (CS) with negative pressure method to solve problems in application of photocatalysts in cementitious materials. Photocatalytic cement material (PCM) was prepared by loading PCS on the surface of cementitious materials, which improved the photocatalytic activity and efficiency of TiO₂ in cementitious materials. It was found that the pore structure (pore volume, size distribution and interconnectivity) of ceramsite sand (CS) varies with particle size. The photocatalytic removal rate of benzene on PCS increased significantly through adjusting ceramsite sands in appropriate pore structure and TiO₂ at best coating ratio. The photocatalytic activity of PCS slightly decreased but still remained active after incorporated into concrete. 2 μL benzene was degraded completely in 200 min by 5 g 4PCS-1.25~2.35 and 300 min by PCM-5, and was still degraded over 80% in 400 min by PCM-5 after exposure to natural environment for 6 months. The results suggested that the photocatalytic activity of TiO₂ in cementitious materials was enhanced by the preparation of PCS and PCM, which could provide more gas diffusion, higher specific surface area, more TiO₂ active sites, and prevent TiO₂ particles from being influenced by the envelope of cement hydration products and the carbonation of cement. Full article

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

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Graphical abstract

12 pages, 437 KiB

Open AccessArticle

Neutral Copper Gas Resistivity Measurements by Means of an Exploding Wire in Air

by Luis Bilbao^1,† and Gonzalo Rodríguez Prieto^2,*,†

¹ Departamento de Fisica, Facultad de Ciencias Exactas, Universidad de Buenos Aires, 1053 Buenos Aires, Argentina

² Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain

^† These authors contributed equally to this work.

Appl. Sci. 2017, 7(8), 829; https://doi.org/10.3390/app7080829 - 12 Aug 2017

Cited by 9 | Viewed by 4054

Abstract

In this work, we present experimentally obtained limits for the values of the neutral copper gas electrical resistivity as a function of the temperature. When a current of about

\approx 10^{3}

A or larger flows through a metallic wire in a microsecond [...] Read more.

In this work, we present experimentally obtained limits for the values of the neutral copper gas electrical resistivity as a function of the temperature. When a current of about

\approx 10^{3}

A or larger flows through a metallic wire in a microsecond or shorter time, the wire performs a phase change from solid to plasma, through intermediate states of metallic liquid and vapor. If the wire is surrounded by a non-conductive dense medium that inhibits the circulation of current outside the wire (e.g., air at room temperature and standard pressure, as in our experiments), the electric current stops when part of the metallic wire becomes gas. This process is known as dark pause, and it has a duration that depends on the experiment parameters. By means of a suitable choice of parameters, we achieved a duration of the dark pause of ≈1

μ

s, which allowed us to determine the limits of the electrical resistivity of the metallic gas. The range of measured values starts from the resistivity of liquid copper at boiling temperature, and goes up to ≈0.01

(\pm 20 %)

Ohm·m at the maximum measured temperature. Full article

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10 pages, 415 KiB

Open AccessArticle

Graphene as a Prototypical Model for Two-Dimensional Continuous Mechanics

by Philippe Lambin

Physics Department, University of Namur, 61 Rue de Bruxelles, B-5000 Namur, Belgium

Appl. Sci. 2017, 7(8), 830; https://doi.org/10.3390/app7080830 - 13 Aug 2017

Cited by 3 | Viewed by 4188

Abstract

This paper reviews a few problems where continuous-medium theory specialized to two-dimensional media provides a qualitatively correct picture of the mechanical behavior of graphene. A critical analysis of the parameters involved is given. Among other results, a simple mathematical description of a folded [...] Read more.

This paper reviews a few problems where continuous-medium theory specialized to two-dimensional media provides a qualitatively correct picture of the mechanical behavior of graphene. A critical analysis of the parameters involved is given. Among other results, a simple mathematical description of a folded graphene sheet is proposed. It is also shown how the graphene–graphene adhesion interaction is related to the cleavage energy of graphite and its

C_{33}

bulk elastic constant. Full article

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

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13 pages, 3269 KiB

Open AccessArticle

Improved Diagnostic Process of Multiple Sclerosis Using Automated Detection and Selection Process in Magnetic Resonance Imaging

by Dror Malka^1,*, Adi Vegerhof², Eyal Cohen²

, Mark Rayhshtat¹, Alex Libenson¹, Maya Aviv Shalev² and Zeev Zalevsky²

¹ Faculty of Engineering, Holon Institute of Technology (HIT), Holon 5810201, Israel

² Faculty of Engineering, Bar-Ilan University, Ramat-Gan 52900, Israel

Appl. Sci. 2017, 7(8), 831; https://doi.org/10.3390/app7080831 - 13 Aug 2017

Cited by 9 | Viewed by 6333

Abstract

In this paper, we present a new method of displaying Magnetic Resonance (MR) images taken from Multiple Sclerosis (MS) patients. We show that our method can potentially make the diagnostic process far more focused and concise. The method is implemented as an algorithm-based [...] Read more.

In this paper, we present a new method of displaying Magnetic Resonance (MR) images taken from Multiple Sclerosis (MS) patients. We show that our method can potentially make the diagnostic process far more focused and concise. The method is implemented as an algorithm-based application, which automatically detects MS lesions and reduces the amount of reviewed images by 98% or more. In contrast to existing detection algorithms, our application utilizes five different types of MR images as well as the Digital Imaging and Communications in Medicine (DICOM) standard, supporting a wide range of data sets. After images are selected for file type and relevant brain region, each image is subjected to four separate algorithms, the results of which are combined into a single displayed image for the use of the diagnosing physician. Full article

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18 pages, 1251 KiB

Open AccessArticle

Modelling the Interruption on HCI Using BDI Agents with the Fuzzy Perceptions Approach: An Interactive Museum Case Study in Mexico

by Ricardo Rosales^1,*

, Manuel Castañón-Puga²

, Felipe Lara-Rosano³

, Richard David Evans⁴

, Nora Osuna-Millan¹ and Maria Virginia Flores-Ortiz¹

¹ Accounting and Administration School, Autonomous University of Baja California, Tijuana 22390, Mexico

² Chemistry and Engineering School, Autonomous University of Baja California, Tijuana 22390, Mexico

³ Complexity Science Center, National Autonomous University of Mexico, Mexico 04510, Mexico

⁴ Business Information Management and Operations Department, University of Westminster, London NW1 5LS, UK

Appl. Sci. 2017, 7(8), 832; https://doi.org/10.3390/app7080832 - 13 Aug 2017

Cited by 9 | Viewed by 6399

Abstract

Technological advancements have revolutionized the proliferation and availability of information to users, which has created more complex and intensive interactions between users and systems. The learning process of users is essential in the construction of new knowledge when pursuing improvements in user experience. [...] Read more.

Technological advancements have revolutionized the proliferation and availability of information to users, which has created more complex and intensive interactions between users and systems. The learning process of users is essential in the construction of new knowledge when pursuing improvements in user experience. In this paper, the interruption factor is considered in relation to interaction quality due to human–computer interaction (HCI) being seen to affect the learning process. We present the results obtained from 500 users in an interactive museum in Tijuana, Mexico as a case study. We model the HCI of an interactive exhibition using belief–desire–intention (BDI) agents; we adapted the BDI architecture using the Type-2 fuzzy inference system to add perceptual human-like capabilities to agents, in order to describe the interaction and interruption factor on user experience. The resulting model allows us to describe content adaptation through the creation of a personalized interaction environment. We conclude that managing interruptions can enhance the HCI, producing a positive learning process that influences user experience. A better interaction may be achieved if we offer the right kind of content, taking the interruptions experienced into consideration. Full article

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

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13 pages, 2071 KiB

Open AccessArticle

Influence of Curing Conditions on the Strength Properties of Polysulfide Polymer Concrete

by Sungnam Hong

College of Engineering, Sungkyunkwan University, Natural Sciences Campus, 2066 Seobu-Ro, Jangan-Gu, Suwon-Si 16419, Gyeonggi-Do, Korea

Appl. Sci. 2017, 7(8), 833; https://doi.org/10.3390/app7080833 - 14 Aug 2017

Cited by 27 | Viewed by 4957

Abstract

In this study, the effects of curing temperature and curing time on the mechanical properties of polysulfide polymer concrete were investigated. For this purpose, several laboratory tests were conducted to measure the compressive, flexural, and bond strengths of the concrete. The ranges of [...] Read more.

In this study, the effects of curing temperature and curing time on the mechanical properties of polysulfide polymer concrete were investigated. For this purpose, several laboratory tests were conducted to measure the compressive, flexural, and bond strengths of the concrete. The ranges of curing temperature and curing time considered were −10–60 °C and 3–672 h (28 days), respectively. The test results show that a curing temperature above 20 °C adversely affects the strength of the concrete. Regression equations derived from the test results demonstrate the reliability of the results for the estimation of flexural and bond strengths from a given value of compressive strength. Full article

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10 pages, 1656 KiB

Open AccessArticle

Longitudinal Removal of Bisphenol-A and Nonylphenols from Pretreated Domestic Wastewater by Tropical Horizontal Sub-SurfaceConstructed Wetlands

by Andrés Toro-Vélez^1,2,*, Carlos Madera-Parra³, Miguel Peña-Varón¹, Hector García-Hernández⁴, Wen Yee Lee⁵, Shane Walker⁶

and Piet Lens⁴

¹ Grupo de Saneamiento Ambiental, Instituto Cinara, Unversidad del Valle, Cali 100-00, Colombia

² Doctorado en Ciencias Ambientales, Universidad del Cauca, Popayán 190001, Colombia

³ Escuela EIDENAR-Facultad de Ingeniería, Universidad del Valle, Cali 100-00, Colombia

⁴ UNESCO-IHE Institute for Water Education, 2611 AX Delft, The Netherlands

⁵ Department of Chemistry, University of Texas at El Paso, El Paso, TX 79968, USA

⁶ Department of Civil Engineering, University of Texas at El Paso, El Paso, TX 79968, USA

Appl. Sci. 2017, 7(8), 834; https://doi.org/10.3390/app7080834 - 15 Aug 2017

Cited by 7 | Viewed by 4923

Abstract

Bisphenol A (BPA) and nonylphenols (NPs), with a high potential to cause endocrine disruption, have been identified at levels of nanograms per liter and even micrograms per liter in effluents from wastewater treatment plants. Constructed wetlands (CWs) are a cost-effective wastewater treatment alternative [...] Read more.

Bisphenol A (BPA) and nonylphenols (NPs), with a high potential to cause endocrine disruption, have been identified at levels of nanograms per liter and even micrograms per liter in effluents from wastewater treatment plants. Constructed wetlands (CWs) are a cost-effective wastewater treatment alternative due to the low operational cost, reduced energy consumption, and lower sludge production, and have shown promising performance for treating these compounds. A CW pilot study was undertaken todetermine its potential to remove BPA and NP from municipal wastewater. Three CWs were used: the first CW was planted with Heliconia sp., a second CW was planted with Phragmites sp., and the third CW was an unplanted control. The removal efficiency of the Heliconia-CW was 73 ± 19% for BPA and 63 ± 20% for NP, which was more efficient than the Phragmites-CW (BPA 70 ± 28% and NP 52 ± 23%) and the unplanted-CW (BPA 62 ± 33% and NP 25 ± 37%). The higher capacity of the Heliconia-CW for BPA and NP removal suggests that a native plant from the tropics can contribute to a better performance of CW for removing these compounds. Full article

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

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15 pages, 5034 KiB

Open AccessArticle

Bisector-Based Tracking of In Plane Subpixel Translations and Rotations

by Julián Espinosa^1,2,*

, Jorge Pérez^1,2, Belén Ferrer³

, Carmen Vázquez^1,2 and David Mas^1,2

¹ Institute of Physics Applied to the Sciences and Technologies, Universidad de Alicante, Carretera San Vicente del Raspeig, s/n, San Vicente del Raspeig, 03690 Alicante, Spain

² Department of Optics, Pharmacology and Anatomy, Universidad de Alicante, Carretera San Vicente del Raspeig, s/n, San Vicente del Raspeig, 03690 Alicante, Spain

³ Department of Civil Engineering, Universidad de Alicante, Carretera San Vicente del Raspeig, s/n, San Vicente del Raspeig, 03690 Alicante, Spain

Appl. Sci. 2017, 7(8), 835; https://doi.org/10.3390/app7080835 - 14 Aug 2017

Viewed by 3791

Abstract

We present a method for distance measuring planar displacements and rotations with image processing methods. The method is based on tracking the intersection of two non-parallel straight segments extracted from a scene. This kind of target can be easily identified in civil structures [...] Read more.

We present a method for distance measuring planar displacements and rotations with image processing methods. The method is based on tracking the intersection of two non-parallel straight segments extracted from a scene. This kind of target can be easily identified in civil structures or in industrial elements or machines. Therefore, our method is suitable for measuring the displacement in some parts of structures and therefore for determining their stress state. We have evaluated the accuracy of our proposal through a computational simulation and validated the method through two lab experiments. We obtained a theoretical mean subpixel accuracy of 0.03 px for the position and 0.02 degrees for the orientation, whereas the practical accuracies were 0.1 px and 0.04 degrees, respectively. One presented lab application deals with the tracking of an object attached to a rotation stage motor in order to characterize the dynamic of the stage, and another application is addressed to the noncontact assessment of the bending and torsional process of a steel beam subjected to load. The method is simple, easy to implement, and widely applicable. Full article

(This article belongs to the Section Optics and Lasers)

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20 pages, 981 KiB

Open AccessArticle

Towards a Predictive Analytics-Based Intelligent Malaria Outbreak Warning System

by Babagana Modu^1,*

, Nereida Polovina², Yang Lan¹, Savas Konur¹, A. Taufiq Asyhari³ and Yonghong Peng⁴

¹ School of Electrical Engineering and Computer Science, University of Bradford, Bradford BD7 1DP, UK

² Manchester Metropolitan University Business School, Manchester Metropolitan University, Manchester M15 6BH, UK

³ Centre for Electronic Warfare, Information and Cyber, Cranfield University, Shrivenham SN6 8LA, UK

⁴ Faculty of Computer Science, University of Sunderland, St Peters Campus, Sunderland SR6 0DD, UK

Appl. Sci. 2017, 7(8), 836; https://doi.org/10.3390/app7080836 - 17 Aug 2017

Cited by 42 | Viewed by 7940

Abstract

Malaria, as one of the most serious infectious diseases causing public health problems in the world, affects about two-thirds of the world population, with estimated resultant deaths close to a million annually. The effects of this disease are much more profound in third [...] Read more.

Malaria, as one of the most serious infectious diseases causing public health problems in the world, affects about two-thirds of the world population, with estimated resultant deaths close to a million annually. The effects of this disease are much more profound in third world countries, which have very limited medical resources. When an intense outbreak occurs, most of these countries cannot cope with the high number of patients due to the lack of medicine, equipment and hospital facilities. The prevention or reduction of the risk factor of this disease is very challenging, especially in third world countries, due to poverty and economic insatiability. Technology can offer alternative solutions by providing early detection mechanisms that help to control the spread of the disease and allow the management of treatment facilities in advance to ensure a more timely health service, which can save thousands of lives. In this study, we have deployed an intelligent malaria outbreak early warning system, which is a mobile application that predicts malaria outbreak based on climatic factors using machine learning algorithms. The system will help hospitals, healthcare providers, and health organizations take precautions in time and utilize their resources in case of emergency. To our best knowledge, the system developed in this paper is the first publicly available application. Since confounding effects of climatic factors have a greater influence on the incidence of malaria, we have also conducted extensive research on exploring a new ecosystem model for the assessment of hidden ecological factors and identified three confounding factors that significantly influence the malaria incidence. Additionally, we deploy a smart healthcare application; this paper also makes a significant contribution by identifying hidden ecological factors of malaria. Full article

(This article belongs to the Special Issue Smart Healthcare)

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12 pages, 2209 KiB

Open AccessArticle

BIM-Based Approach to Simulate Building Adaptive Performance and Life Cycle Costs for an Open Building Design

by Yi-Kai Juan and Nai-Pin Hsing^*

Department of Architecture, National Taiwan University of Science and Technology, No. 43, Sec. 4, Keelung Rd., Taipei 106, Taiwan

Appl. Sci. 2017, 7(8), 837; https://doi.org/10.3390/app7080837 - 15 Aug 2017

Cited by 32 | Viewed by 10571

Abstract

In the long-term use of buildings, renovations are sometimes required as usage behaviors have changed and residents’ demands for space are adjusted. However, the public in general are deficient in renovation knowledge and information regarding building use and its maintenance phases; thus, the [...] Read more.

In the long-term use of buildings, renovations are sometimes required as usage behaviors have changed and residents’ demands for space are adjusted. However, the public in general are deficient in renovation knowledge and information regarding building use and its maintenance phases; thus, the initial stage of planning and design often lacks flexibility, leading to waste materials in the subsequent renovation project. Theoretically, Building Information Modeling (BIM) can be used as a building unit resume and renovation benefit prediction tool; moreover, it plays an important role in the usage and maintenance phases. This study develops three design proposals that target different service lives (30 years, 50 years, 100 years), as based on the building’s expected life, and uses BIM technology to simulate the life cycle cost and design performance, as based on the renovation scenario analysis of the building’s life cycle. The findings show that under the service condition target of 100 years, when the open flexible technique is used for the design, space utilization flexibility is enhanced, pipeline maintenance is convenient, waste is reduced, and performance in life cycle cost is better. BIM can predict performance simply and rapidly according to future usage demand adjustments after the initial design. Full article

(This article belongs to the Special Issue The Industrialization of the Building Construction Process)

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23 pages, 4341 KiB

Open AccessArticle

Effect of Polishing-Induced Subsurface Impurity Defects on Laser Damage Resistance of Fused Silica Optics and Their Removal with HF Acid Etching

by Jian Cheng^1,*, Jinghe Wang¹, Jing Hou², Hongxiang Wang¹ and Lei Zhang¹

¹ School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, China

² Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China

Appl. Sci. 2017, 7(8), 838; https://doi.org/10.3390/app7080838 - 15 Aug 2017

Cited by 39 | Viewed by 8740

Abstract

Laser-induced damage on fused silica optics remains a major issue that limits the promotion of energy output of large laser systems. Subsurface impurity defects inevitably introduced in the practical polishing process incur strong thermal absorption for incident lasers, seriously lowering the laser-induced damage [...] Read more.

Laser-induced damage on fused silica optics remains a major issue that limits the promotion of energy output of large laser systems. Subsurface impurity defects inevitably introduced in the practical polishing process incur strong thermal absorption for incident lasers, seriously lowering the laser-induced damage threshold (LIDT). Here, we simulate the temperature and thermal stress distributions involved in the laser irradiation process to investigate the effect of impurity defects on laser damage resistance. Then, HF-based etchants (HF:NH₄F) are applied to remove the subsurface impurity defects and the surface quality, impurity contents and laser damage resistance of etched silica surfaces are tested. The results indicate that the presence of impurity defects could induce a dramatic rise of local temperature and thermal stress. The maximum temperature and stress can reach up to 7073 K and 8739 MPa, respectively, far higher than the melting point and compressive strength of fused silica, resulting in serious laser damage. The effect of impurity defects on laser damage resistance is dependent on the species, size and spatial location of the defects, and CeO₂ defects play a dominant role in lowering the LIDT, followed by Fe and Al defects. CeO₂ defects with radius of 0.3 μm, which reside 0.15 μm beneath the surface, are the most dangerous defects for incurring laser damage. By HF acid etching, the negative effect of impurity defects on laser damage resistance could be effectively mitigated. It is validated that with HF acid etching, the number of dangerous CeO₂ defects is decreased by more than half, and the LIDT could be improved to 27.1 J/cm². Full article

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

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14 pages, 3134 KiB

Open AccessFeature PaperArticle

Removal of Escherichia coli by Intermittent Operation of Saturated Sand Columns Supplemented with Hydrochar Derived from Sewage Sludge

by Jae Wook Chung^1,*, Oghosa Charles Edewi¹, Jan Willem Foppen¹, Gabriel Gerner², Rolf Krebs² and Piet Nicolaas Luc Lens¹

¹ UNESCO-IHE Institute for Water Education, P.O. BOX 3015, 2601 DA Delft, The Netherlands

² Institute of Natural Resource Sciences, Zurich University of Applied Sciences, Grüental, 8820 Wädenswil, Switzerland

Appl. Sci. 2017, 7(8), 839; https://doi.org/10.3390/app7080839 - 15 Aug 2017

Cited by 18 | Viewed by 5752

Abstract

Hydrothermal carbonization (HTC) technology can convert various types of waste biomass into a carbon-rich product referred to as hydrochar. In order to verify the potential of hydrochar produced from stabilized sewage sludge to be an adsorbent for bacterial pathogen removal in water treatment, [...] Read more.

Hydrothermal carbonization (HTC) technology can convert various types of waste biomass into a carbon-rich product referred to as hydrochar. In order to verify the potential of hydrochar produced from stabilized sewage sludge to be an adsorbent for bacterial pathogen removal in water treatment, the Escherichia coli’s removal efficiency was determined by using 10 cm sand columns loaded with 1.5% (w/w) hydrochar. Furthermore, the removal of E. coli based on intermittent operation in larger columns of 50 cm was measured for 30 days. Since the removal of E. coli was not sufficient when the sand columns were supplemented with raw hydrochar, an additional cold-alkali activation of the hydrochar using potassium hydroxide was applied. This enabled more than 90% of E. coli removal in both the 10 cm and 50 cm column experiments. The enhancement of the E. coli removal efficiency could be attributed to the more hydrophobic surface of the KOH pre-treated hydrochar. The idle time during the intermittent flushing experiments in the sand-only columns without the hydrochar supplement had a significant effect on the E. coli removal (p < 0.05), resulting in a removal efficiency of 55.2%. This research suggested the possible utilization of hydrochar produced from sewage sludge as an adsorbent in water treatment for the removal of bacterial contaminants. Full article

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

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17 pages, 2613 KiB

Open AccessArticle

Effect of Ultrafast Imaging on Shear Wave Visualization and Characterization: An Experimental and Computational Study in a Pediatric Ventricular Model

by Annette Caenen^1,*

, Mathieu Pernot², Ingvild Kinn Ekroll³, Darya Shcherbakova¹, Luc Mertens⁴, Abigail Swillens¹ and Patrick Segers¹

¹ IBiTech-bioMMeda, Ghent University, 9000 Ghent, Belgium

² Institut Langevin, Ecole Supérieure de Physique et de Chimie Industrielles, CNRS UMR 7587, INSERM U979, 75012 Paris, France

³ Circulation and Medical Imaging, Norwegian University of Science and Technology, 7491 Trondheim, Norway

⁴ Hospital for Sick Children, University of Toronto, Toronto, ON M5G 1X8, Canada

Appl. Sci. 2017, 7(8), 840; https://doi.org/10.3390/app7080840 - 16 Aug 2017

Cited by 14 | Viewed by 5258

Abstract

Plane wave imaging in Shear Wave Elastography (SWE) captures shear wave propagation in real-time at ultrafast frame rates. To assess the capability of this technique in accurately visualizing the underlying shear wave mechanics, this work presents a multiphysics modeling approach providing access to [...] Read more.

Plane wave imaging in Shear Wave Elastography (SWE) captures shear wave propagation in real-time at ultrafast frame rates. To assess the capability of this technique in accurately visualizing the underlying shear wave mechanics, this work presents a multiphysics modeling approach providing access to the true biomechanical wave propagation behind the virtual image. This methodology was applied to a pediatric ventricular model, a setting shown to induce complex shear wave propagation due to geometry. Phantom experiments are conducted in support of the simulations. The model revealed that plane wave imaging altered the visualization of the shear wave pattern in the time (broadened front and negatively biased velocity estimates) and frequency domain (shifted and/or decreased signal frequency content). Furthermore, coherent plane wave compounding (effective frame rate of 2.3 kHz) altered the visual appearance of shear wave dispersion in both the experiment and model. This mainly affected stiffness characterization based on group speed, whereas phase velocity analysis provided a more accurate and robust stiffness estimate independent of the use of the compounding technique. This paper thus presents a versatile and flexible simulation environment to identify potential pitfalls in accurately capturing shear wave propagation in dispersive settings. Full article

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

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26 pages, 414 KiB

Open AccessFeature PaperReview

Machine Learning Methods for Pipeline Surveillance Systems Based on Distributed Acoustic Sensing: A Review

by Javier Tejedor¹, Javier Macias-Guarasa^2,*

, Hugo F. Martins³, Juan Pastor-Graells², Pedro Corredera⁴ and Sonia Martin-Lopez²

¹ Department of Information Technology, University CEU San Pablo, 28003 Madrid, Spain

² Department of Electronics, University of Alcalá, 28801 Alcalá de Henares, Spain

³ FOCUS S.L., 28004 Madrid, Spain

⁴ Instituto de Óptica, CSIC, 28006 Madrid, Spain

Appl. Sci. 2017, 7(8), 841; https://doi.org/10.3390/app7080841 - 16 Aug 2017

Cited by 129 | Viewed by 14346

Abstract

There is an increasing interest in researchers and companies on the combination of Distributed Acoustic Sensing (DAS) and a Pattern Recognition System (PRS) to detect and classify potentially dangerous events that occur in areas above fiber optic cables deployed along active pipelines, aiming [...] Read more.

There is an increasing interest in researchers and companies on the combination of Distributed Acoustic Sensing (DAS) and a Pattern Recognition System (PRS) to detect and classify potentially dangerous events that occur in areas above fiber optic cables deployed along active pipelines, aiming to construct pipeline surveillance systems. This paper presents a review of the literature in what respect to machine learning techniques applied to pipeline surveillance systems based on DAS+PRS (although its scope can also be extended to any other environment in which DAS+PRS strategies are to be used). To do so, we describe the fundamentals of the machine learning approaches when applied to DAS systems, and also do a detailed literature review of the main contributions on this topic. Additionally, this paper addresses the most common issues related to real field deployment and evaluation of DAS+PRS for pipeline threat monitoring, and intends to provide useful insights and recommendations in what respect to the design of such systems. The literature review concludes that a real field deployment of a PRS based on DAS technology is still a challenging area of research, far from being fully solved. Full article

(This article belongs to the Special Issue Distributed Optical Fiber Sensors)

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6 pages, 804 KiB

Open AccessArticle

Spectral Correction of CPV Modules Equipped with GaInP/GaInAs/Ge Solar Cells and Fresnel Lenses

by Marios Theristis^1,*

, Eduardo F. Fernández²

, Florencia Almonacid²

and George E. Georghiou¹

¹ PV Technology Laboratory, FOSS Research Centre for Sustainable Energy, Department of Electrical and Computer Engineering, University of Cyprus, Nicosia 1678, Cyprus

² Centre for Advanced Studies on Energy and Environment (CEAEMA), IDEA Solar Energy Research Group, Electronics and Automation Engineering Department, University of Jaén, Las Lagunillas Campus, 23071 Jaén, Spain

Appl. Sci. 2017, 7(8), 842; https://doi.org/10.3390/app7080842 - 16 Aug 2017

Cited by 9 | Viewed by 4162

Abstract

Photovoltaic (PV) devices are spectrally selective, and their performance is influenced by unavoidable spectral variations. In addition, multijunction-based concentrating photovoltaic (CPV) devices show a strong spectral dependence due to the series connection of various junctions with different absorption bands, and also due to [...] Read more.

Photovoltaic (PV) devices are spectrally selective, and their performance is influenced by unavoidable spectral variations. In addition, multijunction-based concentrating photovoltaic (CPV) devices show a strong spectral dependence due to the series connection of various junctions with different absorption bands, and also due to the use of concentrator optics. In this work, the accuracy of a new set of analytical equations that quantify the spectral impact caused by the changes in air mass (AM), aerosol optical depth (AOD) and precipitable water (PW) is discussed. Four different CPV devices based on lattice-matched and metamorphic triple-junction solar cells and a poly(methyl methacrylate) (PMMA) and silicon-on-glass (SoG) Fresnel lenses are considered. A long-term outdoor experimental campaign was carried out at the Centre for Advanced Studies on Energy and Environment (CEAEMA) of the University of Jaén, Spain. Results show a high accuracy in the estimations of the spectral factor (SF), with an average mean absolute percentage error (MAPE) within 0.91% and a mean relative error (MRE) within −0.32%. Full article

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

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18 pages, 3639 KiB

Open AccessFeature PaperArticle

New Approaches for Supervision of Systems with Sliding Wear: Fundamental Problems and Experimental Results Using Different Approaches

by Dirk Söffker

and Sandra Rothe^*

Chair of Dynamics and Control, University of Duisburg-Essen, Lotharstrasse 65, 47057 Duisburg, Germany

Appl. Sci. 2017, 7(8), 843; https://doi.org/10.3390/app7080843 - 16 Aug 2017

Cited by 8 | Viewed by 4714

Abstract

Reliability and availability of technically complex and safety-critical systems are of increasing importance. Besides the degree of wear, the quality of mechanical systems is significant for the system reliability. The focus of this contribution is the development and application of readily applicable and [...] Read more.

Reliability and availability of technically complex and safety-critical systems are of increasing importance. Besides the degree of wear, the quality of mechanical systems is significant for the system reliability. The focus of this contribution is the development and application of readily applicable and easily interpretable algorithms for industrial data obtained from technical systems during operation. The methods are within the focus of the production-oriented automation programs (Industrial Internet, Automation 4.0, China 2025). In this contribution as example a hydraulically driven machine in which parts slide over each other is chosen as sliding wear example. Monitoring is applied to distinguish normal and abnormal operation as well as to define end of useful lifetime. In this contribution four different methods will be introduced and experimentally compared without the availability of objective information about the wear state. The approaches differ with respect to the used measurements and data preparation. As measurements Acoustic Emission and the hydraulic pressure of the driving machine are used. For processing the accumulation of damage related values, a machine learning algorithm, and a sensitivity matrix are used. For comparison the experimental validation is based on identical data sets. Different operational states of the system denoted as actual system state are defined and classified. The comparison shows that the four introduced methods provide similar classification results although the underlying measurements are based on different physical principles. The newly introduced approaches allow online evaluation of the actual system state and can serve within improved maintenance strategies. Full article

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7 pages, 2075 KiB

Open AccessArticle

Amorphous InGaZnO Thin Film Transistor Fabricated with Printed Silver Salt Ink Source/Drain Electrodes

by Caigui Yang¹, Zhiqiang Fang¹, Honglong Ning^1,*

, Ruiqiang Tao¹, Jianqiu Chen¹

, Yicong Zhou¹, Zeke Zheng¹, Rihui Yao^1,*

, Lei Wang¹, Junbiao Peng¹ and Yongsheng Song²

¹ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China

² Guangdong Fenghua Advanced Technology Holding Co., Ltd., Zhaoqing 526060, China

Appl. Sci. 2017, 7(8), 844; https://doi.org/10.3390/app7080844 - 16 Aug 2017

Cited by 18 | Viewed by 6539

Abstract

Recently, amorphous indium-gallium-zinc-oxide thin film transistors (a-IGZO TFTs) with inkjet printing silver source/drain electrodes have attracted great attention, especially for large area and flexible electronics applications. The silver ink could be divided into two types: one is based on silver nanoparticles, and the [...] Read more.

Recently, amorphous indium-gallium-zinc-oxide thin film transistors (a-IGZO TFTs) with inkjet printing silver source/drain electrodes have attracted great attention, especially for large area and flexible electronics applications. The silver ink could be divided into two types: one is based on silver nanoparticles, and the other is silver salt ink. Organic materials are essential in the formulation of nanoparticle ink as a strong disperse stabilizer to prevent agglomeration of silver particles, but will introduce contact problems between the silver electrodes and the a-IGZO active layer after annealing, which is difficult to eliminate and leads to poor device properties. Our experiment is aimed to reduce this effect by using a silver salt ink without stabilizer component. With optimized inkjet printing conditions, the high performance of a-IGZO TFT was obtained with a mobility of 4.28 cm²/V·s and an on/off current ratio over 10⁶. The results have demonstrated a significant improvement for a-IGZO TFTs with directly printed silver electrodes. This work presents a promising platform for future printed electronic applications. Full article

(This article belongs to the Special Issue Thin-Film Transistor)

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20 pages, 8247 KiB

Open AccessArticle

Broken Rotor Bar Detection in LS-PMSM Based on Startup Current Analysis Using Wavelet Entropy Features

by Mohammad Rezazadeh Mehrjou^1,2

, Norman Mariun^1,2, Norhisam Misron^2,*, Mohd Amran Mohd Radzi^1,2

and Suleiman Musa^1,2

¹ Department of Electrical and Electronic Engineering, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia

² Centre of Advanced Power and Energy Research (CAPER), Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia

Appl. Sci. 2017, 7(8), 845; https://doi.org/10.3390/app7080845 - 17 Aug 2017

Cited by 21 | Viewed by 7765

Abstract

High-efficiency motors are being gradually introduced in many industrial applications because of their positive impacts on the environment by reducing energy consumption and CO₂ emission. In this respect, line start permanent magnet synchronous motors (LS-PMSMs) have been introduced recently. Due to their [...] Read more.

High-efficiency motors are being gradually introduced in many industrial applications because of their positive impacts on the environment by reducing energy consumption and CO₂ emission. In this respect, line start permanent magnet synchronous motors (LS-PMSMs) have been introduced recently. Due to their unique configuration, LS-PMSMs allow the obtaining of super premium efficiency levels, accompanied with a high torque and power factor. However, since the use of LS-PMSMs in the industry is in its infancy, no efficient scheme has yet been reported for broken rotor bar (BRB) fault detection in this type of motor. Accordingly, the main aim of this research is to investigate the fault-related feature for BRB faults on LS-PMSMs. In this regard, a simulation model and experimental setup for the investigation of BRB in LS-PMSM are implemented. The detection strategy for BRB in LS-PMSM proposed here is based on the monitoring of the start-up current signal and discrete wavelet transform. The entropy features are used as fault-related features for BRB faults. Finally, the ability of these features is validated for the detection of BRB in LS-PMSM through statistical analysis. In this research, the importance of the starting load is also considered for BRB detection in LS-PMSMs. Full article

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12 pages, 252 KiB

Open AccessArticle

Learning Word Embeddings with Chi-Square Weights for Healthcare Tweet Classification

by Sicong Kuang^* and Brian D. Davison

Department of Computer Science and Engineering, Lehigh University, 19 Memorial Dr. West, Bethlehem, PA 18015, USA

Appl. Sci. 2017, 7(8), 846; https://doi.org/10.3390/app7080846 - 17 Aug 2017

Cited by 28 | Viewed by 5123

Abstract

Twitter is a popular source for the monitoring of healthcare information and public disease. However, there exists much noise in the tweets. Even though appropriate keywords appear in the tweets, they do not guarantee the identification of a truly health-related tweet. Thus, the [...] Read more.

Twitter is a popular source for the monitoring of healthcare information and public disease. However, there exists much noise in the tweets. Even though appropriate keywords appear in the tweets, they do not guarantee the identification of a truly health-related tweet. Thus, the traditional keyword-based classification task is largely ineffective. Algorithms for word embeddings have proved to be useful in many natural language processing (NLP) tasks. We introduce two algorithms based on an existing word embedding learning algorithm: the continuous bag-of-words model (CBOW). We apply the proposed algorithms to the task of recognizing healthcare-related tweets. In the CBOW model, the vector representation of words is learned from their contexts. To simplify the computation, the context is represented by an average of all words inside the context window. However, not all words in the context window contribute equally to the prediction of the target word. Greedily incorporating all the words in the context window will largely limit the contribution of the useful semantic words and bring noisy or irrelevant words into the learning process, while existing word embedding algorithms also try to learn a weighted CBOW model. Their weights are based on existing pre-defined syntactic rules while ignoring the task of the learned embedding. We propose learning weights based on the words’ relative importance in the classification task. Our intuition is that such learned weights place more emphasis on words that have comparatively more to contribute to the later task. We evaluate the embeddings learned from our algorithms on two healthcare-related datasets. The experimental results demonstrate that embeddings learned from the proposed algorithms outperform existing techniques by a relative accuracy improvement of over 9%. Full article

(This article belongs to the Special Issue Smart Healthcare)

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15 pages, 1584 KiB

Open AccessArticle

Reformulation-Linearization Technique Approach for Kidney Exchange Program IT Healthcare Platforms

by Junsang Yuh^1,2, Seokhyun Chung² and Taesu Cheong^2,*

¹ R&D Center, Begas, Seoul 06179, Korea

² School of Industrial Management Engineering, Korea University, Seoul 02841, Korea

Appl. Sci. 2017, 7(8), 847; https://doi.org/10.3390/app7080847 - 17 Aug 2017

Cited by 6 | Viewed by 5861

Abstract

Kidney exchange allows a potential living donor whose kidney is incompatible with his intended recipient to donate a kidney to another patient so that the donor’s intended recipient can receive a compatible kidney from another donor. These exchanges can include cycles of longer [...] Read more.

Kidney exchange allows a potential living donor whose kidney is incompatible with his intended recipient to donate a kidney to another patient so that the donor’s intended recipient can receive a compatible kidney from another donor. These exchanges can include cycles of longer than two donor–patient pairs and chains produced by altruistic donors. Kidney exchange programs (KEPs) can be modeled as a maximum-weight cycle-packing problem in a directed graph. This paper develops a new integer programming model for KEPs by applying the reformulation-linearization technique (RLT) to enhance a lower bound obtained by its linear programming (LP) relaxation. Given the results obtained from the proposed model, the model is expected to be utilized in the integrated KEP IT (Information Technology) healthcare platform to obtain plans for optimized kidney exchanges. Full article

(This article belongs to the Special Issue Smart Healthcare)

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19 pages, 10477 KiB

Open AccessArticle

Thermo-Responsive Shape-Memory Effect and Surface Features in Polycarbonate (PC)

by Xuelian Wu¹, Taoxi Wang², Weimin Huang^2,* and Yong Zhao³

¹ School of Mechanical Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China

² School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore

³ School of Chemistry and Chemical Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China

Appl. Sci. 2017, 7(8), 848; https://doi.org/10.3390/app7080848 - 17 Aug 2017

Cited by 11 | Viewed by 6350

Abstract

The influence of programming strain and temperature on the shape memory effect and surface morphology in programmed polycarbonate (PC) samples via uni-axial stretching is investigated. It is found that the samples programmed at around the glass transition start temperature not only have micro-cracks [...] Read more.

The influence of programming strain and temperature on the shape memory effect and surface morphology in programmed polycarbonate (PC) samples via uni-axial stretching is investigated. It is found that the samples programmed at around the glass transition start temperature not only have micro-cracks on their surface, but also show a necking phenomenon. Furthermore, the surface of the necked area is concave, but the surface of the non-necked area is convex. On the other hand, despite the samples programmed at high temperatures being able to deform in a uniform manner at macroscopic scale, their surfaces are still uneven, either concave or convex. While the samples programmed at low temperatures are able to achieve full shape recovery, stretching at higher temperatures over the glass transition range to a higher strain may result in non-recoverable deformation. Full article

(This article belongs to the Special Issue Shape Memory Polymers)

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24 pages, 3323 KiB

Open AccessArticle

An Efficient Retrieval Technique for Trademarks Based on the Fuzzy Inference System

by Chin-Sheng Chen^*

and Chi-Min Weng

Graduate Institute of Automation Technology, National Taipei University of Technology, 1, Sec. 3, Zhongxiao E. Rd, Taipei 10608, Taiwan

Appl. Sci. 2017, 7(8), 849; https://doi.org/10.3390/app7080849 - 18 Aug 2017

Cited by 7 | Viewed by 4873

Abstract

The existing trademark image retrieval (TIR) approaches mostly use complex image features, the integration of multi features, a tree structure, etc. to enable highly accurate retrieval. However, there is the heavy computational burden for complex image features and maximum similarity subtree isomorphism (MSSI) [...] Read more.

The existing trademark image retrieval (TIR) approaches mostly use complex image features, the integration of multi features, a tree structure, etc. to enable highly accurate retrieval. However, there is the heavy computational burden for complex image features and maximum similarity subtree isomorphism (MSSI) measurement. This paper aims to provide an efficient solution for TIR in real-time applications, especially in measuring the similarity between multi-object trademark images. In particular, we propose a novel algorithm for tree similarity measurement based on the fuzzy inference system (FIS) to improve retrieval efficiency. Furthermore, the integration of global and local geometric descriptors is used to enable accurate retrieval. The global descriptor is computed by employing the Hu moments, while the local descriptors are generated by using a tree structure based on the five geometric features: convexity, eccentricity, compactness, circle variance, and elliptic variance. During the retrieval process, the similarity coefficient between the query and the database image is obtained from the similarity of the global and local descriptors. The proposed technique is evaluated using 1800 trademark images, including 12 different classes and 416 trademark images. Additionally, the three common indices, the precision/recall rate, the Bull’s eye score, and the average normalized modified retrieval rank (ANMRR) are used as the performance indices. The experimental results show that the proposed technique is superior to the other two competitive approaches. It shows 19.43% and 26.78% precision/recall improvement, 19.56% and 30.58% improvement in the average Bull’s eye score, and 0.167 and 0.236 improvement in the ANMRR score, respectively, for the 416 query images. It can be concluded from the experimental analysis that the proposed technique not only provides reliable retrieval results but also improves the retrieval efficiency by 151 times in the retrieval process. Full article

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

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20 pages, 5424 KiB

Open AccessFeature PaperReview

The Linac Coherent Light Source: Recent Developments and Future Plans

by R. W. Schoenlein^*, S. Boutet, M. P. Minitti and A.M. Dunne

SLAC National Accelerator Laboratory, Linac Coherent Light Source, 2575 Sand Hill Rd, Menlo Par, CA 94025, USA

Appl. Sci. 2017, 7(8), 850; https://doi.org/10.3390/app7080850 - 18 Aug 2017

Cited by 46 | Viewed by 8615

Abstract

The development of X-ray free-electron lasers (XFELs) has launched a new era in X-ray science by providing ultrafast coherent X-ray pulses with a peak brightness that is approximately one billion times higher than previous X-ray sources. The Linac Coherent Light Source (LCLS) facility [...] Read more.

The development of X-ray free-electron lasers (XFELs) has launched a new era in X-ray science by providing ultrafast coherent X-ray pulses with a peak brightness that is approximately one billion times higher than previous X-ray sources. The Linac Coherent Light Source (LCLS) facility at the SLAC National Accelerator Laboratory, the world’s first hard X-ray FEL, has already demonstrated a tremendous scientific impact across broad areas of science. Here, a few of the more recent representative highlights from LCLS are presented in the areas of atomic, molecular, and optical science; chemistry; condensed matter physics; matter in extreme conditions; and biology. This paper also outlines the near term upgrade (LCLS-II) and motivating science opportunities for ultrafast X-rays in the 0.25–5 keV range at repetition rates up to 1 MHz. Future plans to extend the X-ray energy reach to beyond 13 keV (<1 Å) at high repetition rate (LCLS-II-HE) are envisioned, motivated by compelling new science of structural dynamics at the atomic scale. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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11 pages, 523 KiB

Open AccessFeature PaperArticle

Formulation of Laccase Nanobiocatalysts Based on Ionic and Covalent Interactions for the Enhanced Oxidation of Phenolic Compounds

by Maria Teresa Moreira^*, Yolanda Moldes-Diz

, Sara Feijoo, Gemma Eibes

, Juan M. Lema and Gumersindo Feijoo

Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain

Appl. Sci. 2017, 7(8), 851; https://doi.org/10.3390/app7080851 - 18 Aug 2017

Cited by 17 | Viewed by 5016

Abstract

Oxidative biocatalysis by laccase arises as a promising alternative in the development of advanced oxidation processes for the removal of xenobiotics. The aim of this work is to develop various types of nanobiocatalysts based on laccase immobilized on different superparamagnetic and non-magnetic nanoparticles [...] Read more.

Oxidative biocatalysis by laccase arises as a promising alternative in the development of advanced oxidation processes for the removal of xenobiotics. The aim of this work is to develop various types of nanobiocatalysts based on laccase immobilized on different superparamagnetic and non-magnetic nanoparticles to improve the stability of the biocatalysts. Several techniques of enzyme immobilization were evaluated based on ionic exchange and covalent bonding. The highest yields of laccase immobilization were achieved for the covalent laccase nanoconjugates of silica-coated magnetic nanoparticles (2.66 U mg⁻¹ NPs), formed by the covalent attachment of the enzyme between the aldehyde groups of the glutaraldehyde-functionalized nanoparticle and the amino groups of the enzyme. Moreover, its application in the biotransformation of phenol as a model recalcitrant compound was tested at different pH and successfully achieved at pH 6 for 24 h. A sequential batch operation was carried out, with complete recovery of the nanobiocatalyst and minimal deactivation of the enzyme after four cycles of phenol oxidation. The major drawback associated with the use of the nanoparticles relies on the energy consumption required for their production and the use of chemicals, that account for a major contribution in the normalized index of 5.28 × 10⁻³. The reduction of cyclohexane (used in the synthesis of silica-coated magnetic nanoparticles) led to a significant lower index (3.62 × 10⁻³); however, the immobilization was negatively affected, which discouraged this alternative. Full article

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

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11 pages, 3286 KiB

Open AccessArticle

Silver Nanoparticles-Loaded Exfoliated Graphite and Its Anti-Bacterial Performance

by Shiyu Hou^1,2, Jihui Li¹, Xiaochuan Huang³, Xiaomao Wang³, Liqiang Ma², Wanci Shen¹, Feiyu Kang¹ and Zheng-Hong Huang^1,*

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

² School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China

³ State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environment, Tsinghua University, Beijing 100084, China

Appl. Sci. 2017, 7(8), 852; https://doi.org/10.3390/app7080852 - 18 Aug 2017

Cited by 25 | Viewed by 6254

Abstract

One antibacterial material was prepared from exfoliated graphite (EG) decorated with silver nanoparticles (AgNPs). The EG was prepared by the graphite intercalated compound process, AgNPs were prepared by chemical reduction of AgNO₃ in the presence of NaBH₄. The AgNPs-loaded EG [...] Read more.

One antibacterial material was prepared from exfoliated graphite (EG) decorated with silver nanoparticles (AgNPs). The EG was prepared by the graphite intercalated compound process, AgNPs were prepared by chemical reduction of AgNO₃ in the presence of NaBH₄. The AgNPs-loaded EG (Ag-EG) composite was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), nitrogen adsorption, mercury intrusion porosimetry, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The antibacterial effect of the Ag-EG was evaluated by using the zone of inhibition method. The loaded AgNPs were highly dispersed on EG sheets and most of them have a size less than 10 nm. The Ag loading slightly increased the surface area of EG. It is shown that the Ag-EG had antibacterial activity and anti-adhesion properties against Pseudomonas aeruginosa and Staphylococcus aureus. It suggests that Ag-EG composites could be used in a variety of industrial applications that require an antibacterial effect. Full article

(This article belongs to the Special Issue Nano-systems for Antimicrobial Therapy)

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12 pages, 1153 KiB

Open AccessArticle

FE Model and Operational Modal Analysis of Lower Limbs

by Aymeric Pionteck¹, Xavier Chiementin^2,*, Marcela Munera³, Sébastien Murer², Delphine Chadefaux⁴ and Guillaume Rao⁴

¹ Mines de St-Étienne, 158 cours Fauriel, 42023 Saint-Étienne CEDEX 2, France

² GRESPI, Groupe de Recherche En Science Pour l’Ingenieur, Université de Reims Champagne-Ardenne, 51687 Reims CEDEX 2, France

³ Escuela Colombiana de Ingeniería Julio Garavito, Bogotá D.C. 111166, Colombia

⁴ Aix Marseille Univ, CNRS, ISM, 13284 Marseille, France

Appl. Sci. 2017, 7(8), 853; https://doi.org/10.3390/app7080853 - 18 Aug 2017

Cited by 1 | Viewed by 5874

Abstract

Human lower limbs are exposed to vibrations on a daily basis, during work, transport or sports. However, most of the FE (Finite Elements) and OMA (Operational Modal Analysis) studies focus either on the whole body or on the hand-arm system. The study presented [...] Read more.

Human lower limbs are exposed to vibrations on a daily basis, during work, transport or sports. However, most of the FE (Finite Elements) and OMA (Operational Modal Analysis) studies focus either on the whole body or on the hand-arm system. The study presented herein aims at identifying the modal parameters of the lower limbs using a 2D FE model updated using OMA. A numerical model is proposed, and a modal analysis has been performed on 11 subjects. Two repeatable modal frequencies were extracted:

52.54 \pm 2.05 Hz

and

118.94 \pm 2.70 Hz

, which were used to update the mechanical properties of the numerical model. The knowledge of these modal characteristics makes it possible to design new equipment that would absorb these specific vibrations and possibly reduce the risk of related diseases in the field of sports and transport. Full article

(This article belongs to the Section Mechanical Engineering)

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11 pages, 3050 KiB

Open AccessArticle

Irradiation Induced Defect Clustering in Zircaloy-2

by Zhongwen Yao^*, Mark Daymond, Sali Di and Yasir Idrees

Department of Mechanical and Materials Engineering, Queen’s University, Kingston, ON K7L 3N6, Canada

Appl. Sci. 2017, 7(8), 854; https://doi.org/10.3390/app7080854 - 18 Aug 2017

Cited by 11 | Viewed by 5080

Abstract

The effect of irradiation temperature and alloying elements on defect clustering behaviour directly from the cascade collapse in Zircaloy-2 is examined. The in-situ ioWn irradiation technique was employed to study the formation of <a>-type dislocation loops by Kr ion irradiation at 573 K [...] Read more.

The effect of irradiation temperature and alloying elements on defect clustering behaviour directly from the cascade collapse in Zircaloy-2 is examined. The in-situ ioWn irradiation technique was employed to study the formation of <a>-type dislocation loops by Kr ion irradiation at 573 K and 773 K, while the dependence of dislocation loop formationon the presence of alloying elements was investigated by comparing with the defect microstructures of pure Zr irradiated under similar conditions. The experimentally observed temperature dependence of defect clustering was further investigated using molecular dynamics (MD) simulations near the experimental irradiation temperatures. We particularly concentrate on yield and morphology of small defect clusters formed directly from cascade collapse at very low ion doses. Smaller loop size and higher defect yield (DY) in Zircaloy-2 as compared to pure Zr suggests that the presence of the major alloying element Sn increases the number of nucleation sites for the defect clusters but suppresses the point defect recombination. MD simulations at 600 and 800 K revealed that the production of both vacancy and interstitial clusters drops significantly with an increase of irradiation temperature, which is reflected in experimentally collected DY data. Full article

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

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11 pages, 1190 KiB

Open AccessArticle

Probing Structures of Interfacial 1-Butyl-3-Methylimidazolium Trifluoromethanesulfonate Ionic Liquid on Nano-Aluminum Oxide Surfaces Using High-Pressure Infrared Spectroscopy

by Hai-Chou Chang^1,*

, Teng-Hui Wang¹ and Christopher M. Burba²

¹ Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan

² Department of Natural Science, Northeastern State University, Tahlequah, OK 74464, USA

Appl. Sci. 2017, 7(8), 855; https://doi.org/10.3390/app7080855 - 18 Aug 2017

Cited by 15 | Viewed by 4721

Abstract

The interactions between 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM][TFS]) and nano-Al₂O₃ are studied using high-pressure infrared spectroscopy. The thickness of the [BMIM][TFS] interfacial layer on the aluminum oxide are adjusted by controlling the number of washes with ethanol. In contrast to the results [...] Read more.

The interactions between 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM][TFS]) and nano-Al₂O₃ are studied using high-pressure infrared spectroscopy. The thickness of the [BMIM][TFS] interfacial layer on the aluminum oxide are adjusted by controlling the number of washes with ethanol. In contrast to the results obtained under ambient pressure, local structures of both the cations and anions of [BMIM][TFS] are disturbed under high pressures. For example, bands due to C-H stretching motions display remarkable blue-shifts in frequency as the pressure of the [BMIM][TFS]/Al₂O₃ composites is increased to 0.4 GPa. The bands then undergo mild shifts in frequency upon further compression. The discontinuous jump occurring around 0.4 GPa becomes less obvious when the amount of ionic liquid on the Al₂O₃ is reduced by washing with ethanol. The nano-Al₂O₃ with surfaces may weaken the cation/anion interactions in the interfacial area as a result of the formation of pressure-enhanced Al₂O₃/ionic liquid interactions under high pressures. Full article

(This article belongs to the Special Issue Optics and Spectroscopy for Fluid Characterization)

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19 pages, 8964 KiB

Open AccessFeature PaperArticle

Suppressing Salt Transport through Composite Pervaporation Membranes for Brine Desalination

by Lin Li¹, Jingwei Hou^1,*

, Yun Ye¹, Jaleh Mansouri^1,2, Yatao Zhang³

and Vicki Chen¹

¹ The United Nations Educational, Scientific and Cultural Organization (UNESCO) Centre for Membrane Science and Technology, School of Chemical Engineering, University of New South Wales, Sydney 2052, Australia

² Cooperative Research Centre for Polymers, Notting Hill 3168, Australia

³ School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou 450001, China

Appl. Sci. 2017, 7(8), 856; https://doi.org/10.3390/app7080856 - 19 Aug 2017

Cited by 30 | Viewed by 8315

Abstract

Pervaporation membranes have gained renewed interest in challenging feedwaters desalination, such as reverse osmosis (RO) concentrated brine wastewater. In this study, composite polyvinyl alcohol (PVA)/polyvinylidene fluoride (PVDF) pervaporation membranes were prepared for brine treatment. The composite membrane was firstly studied by adjusting the [...] Read more.

Pervaporation membranes have gained renewed interest in challenging feedwaters desalination, such as reverse osmosis (RO) concentrated brine wastewater. In this study, composite polyvinyl alcohol (PVA)/polyvinylidene fluoride (PVDF) pervaporation membranes were prepared for brine treatment. The composite membrane was firstly studied by adjusting the cross-linking density of PVA by glutaraldehyde: the membrane with higher cross-linking density exhibited much higher salt rejection efficiency for long-term operation. A trace of salt on the permeate side was found to diffuse through the membrane in the form of hydrated ions, following solution-diffusion mechanism. To further suppress the salt transport and achieve long-term stable operation, graphene oxide (GO) was incorporated into the PVA layer: the addition of GO had minor effects on water permeation but significantly suppressed the salt passage, compared to the pure PVA/PVDF membranes. In terms of brine wastewater containing organic/inorganic foulant, improved anti-fouling performance was also observed with GO-containing membranes. Furthermore, the highest flux of 28 L/m²h was obtained for the membrane with 0.1 wt. % of GO using 100 g/L NaCl as the feed at 65 °C by optimising the pervaporation rig, with permeate conductivity below 1.2 µS/cm over 24 h (equivalent to a salt rejection of >99.99%). Full article

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

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5 pages, 299 KiB

Open AccessArticle

Development and Application of Sub-Cycle Mid-Infrared Source Based on Laser Filamentation

by Takao Fuji^*, Hideto Shirai and Yutaka Nomura

Center for Mesoscopic Sciences, Institute for Molecular Science, 38 Nishigonaka, Myodaiji. Okazaki 444-8585, Japan

Appl. Sci. 2017, 7(8), 857; https://doi.org/10.3390/app7080857 - 19 Aug 2017

Cited by 4 | Viewed by 4585

Abstract

This paper is a perspective article which summarizes the development and application of sub-cycle mid-infrared (MIR) pulses generated through a laser filament. The generation scheme was published in Applied Sciences in 2013. The spectrum of the MIR pulse spreads from 2 to 50 [...] Read more.

This paper is a perspective article which summarizes the development and application of sub-cycle mid-infrared (MIR) pulses generated through a laser filament. The generation scheme was published in Applied Sciences in 2013. The spectrum of the MIR pulse spreads from 2 to 50

μ

m, corresponding to multiple octaves, and the pulse duration is 6.9 fs, namely, 0.63 times the period of the carrier wavelength, 3.3

μ

m. The extremely broadband and highly coherent light source has potential for various applications. The light source has been applied for advanced ultrafast pump–probe spectroscopy by several research groups. As another application example, single-shot detection of absorption spectra in the entire MIR range by the use of chirped-pulse upconversion with a gas medium has been demonstrated. Although the measurement of the field oscillation of the sub-cycle MIR pulse was not trivial, the waveform of the sub-cycle pulse has been completely characterized with a newly developed method, frequency-resolved optical gating capable of carrier-envelope phase determination. A particular behavior of the spectral phase of the sub-cycle pulse has been revealed through the waveform characterization. Full article

(This article belongs to the Section Optics and Lasers)

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7 pages, 2614 KiB

Open AccessArticle

Image Analysis of Dynamic Brain Activity Based on Gray Distance Compensation

by Ying Wang^1,2, Yung-Tian A. Gau³, Hanh N. D. Le²

, Dwight E. Bergles^3,4 and Jin U. Kang^2,*

¹ School of Information Science and Technology, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Beijing 100029, China

² Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218, USA

³ Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA

⁴ Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA

Appl. Sci. 2017, 7(8), 858; https://doi.org/10.3390/app7080858 - 19 Aug 2017

Cited by 2 | Viewed by 3878

Abstract

Assessing time-dependent changes in brain activity is of crucial importance in neuroscience. Here, we propose a novel image processing method to automatically identify active regions and assess time-dependent changes in fluorescence arising from genetically encoded indicators of activity. First, potential active regions and [...] Read more.

Assessing time-dependent changes in brain activity is of crucial importance in neuroscience. Here, we propose a novel image processing method to automatically identify active regions and assess time-dependent changes in fluorescence arising from genetically encoded indicators of activity. First, potential active regions and the corresponding active centers were extracted based on gray distance compensation. Then potential active regions were aligned through frames and, if meeting pre-determined intensity criteria, were accepted as active regions and the fluorescence changes were quantified. We validated this method with independent in vivo imaging datasets collected from transgenic mice that express the genetically encoded calcium indicator GCaMP3. Our studies indicate that the incorporation of this gray distance compensation-based algorithm substantially improves the accuracy and efficiency of detecting and quantifying cellular activity in the intact brain. Full article

(This article belongs to the Section Optics and Lasers)

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10 pages, 2106 KiB

Open AccessArticle

Influences of Doping and Crystal Orientation on Surface Roughening upon Alcohol Grafting onto Silicon Hydride

by Joline Tung¹ and Yit Lung Khung^2,*

¹ College of Arts and Sciences, University of North Carolina at Chapel Hill (UNC), Chapel Hill, NC 27514, USA

² Institute of New Drug Development, ChinaMedical University, No. 91 Hsueh-Shih Road, Taichung 40402, Taiwan

Appl. Sci. 2017, 7(8), 859; https://doi.org/10.3390/app7080859 - 21 Aug 2017

Cited by 7 | Viewed by 6796

Abstract

An alcohol bearing alkyne was thermally grafted to both p-type and n-type silicon (111) and (100) substrate of comparable doping levels and surface flatness. The surface topography as well as the surface chemistry was examined via atomic force microscopy (AFM), X-ray [...] Read more.

An alcohol bearing alkyne was thermally grafted to both p-type and n-type silicon (111) and (100) substrate of comparable doping levels and surface flatness. The surface topography as well as the surface chemistry was examined via atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and water contact angle measurements. P-type silicon (111) was observed to experience roughening on the surface upon functionalization while n-type silicon (111) surfaces remained relatively unchanged. When the alcohol was grafted onto silicon (100) surface, the roughening effect was found to be even more profound for the p-type while the effects were marginal for the n-type surfaces. Both roughening effects were attributed to the differential weakening of the Si–Si backbond induced by majority carriers in p- and n-type silicon while (111) was observed to be able to resist the roughening effect better and this was explained by the notion of its denser adatom surface packing as well as the presence of surface defects. Full article

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

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19 pages, 4969 KiB

Open AccessArticle

Design, Analysis and Fabrication of a Novel Transverse Flux Permanent Magnet Machine with Disk Rotor

by Hosein Azarinfar and Mohammad R Aghaebrahimi^*

Faculty of Electrical & Computer Engineering, University of Birjand, Birjand 97175, Iran

Appl. Sci. 2017, 7(8), 860; https://doi.org/10.3390/app7080860 - 21 Aug 2017

Cited by 6 | Viewed by 4742

Abstract

The purpose of this paper is to propose a novel design for the transverse flux permanent magnet (TFPM) disk-rotor generator with E and I-shaped cores (TFPMDEIG). Disk-shape structure increases the machine’s power factor, allows for high rotational speeds, decreases centrifugal force over permanent [...] Read more.

The purpose of this paper is to propose a novel design for the transverse flux permanent magnet (TFPM) disk-rotor generator with E and I-shaped cores (TFPMDEIG). Disk-shape structure increases the machine’s power factor, allows for high rotational speeds, decreases centrifugal force over permanent magnets, and is employed in wind turbines, due to its compact structures. As for other advantages for this structure, one can point to the fact that there are as many windings as machine’s pole pairs; these windings become parallel by observing the polarity. In other words, the total power of this machine is distributed between pole pairs, increasing the overall reliability of the machine. In this paper, first, the initial design algorithm and the basic formulas governing the behavior of the proposed structure using the equivalent magnetic circuit for each pole are provided, and the three-dimensional finite element method (3D-FEM) is used for verification of the algorithm. To validate the simulation results (3D-FEM), then, a prototype has been fabricated and experienced. The experimental results are in good agreement with simulation results. Full article

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18 pages, 891 KiB

Open AccessArticle

Global Analysis for an HIV Infection Model with CTL Immune Response and Infected Cells in Eclipse Phase

by Karam Allali¹, Jaouad Danane¹

and Yang Kuang^2,*

¹ Laboratory of Mathematics and Applications, Faculty of Sciences and Technologies, University Hassan II of Casablanca, P.O. Box 146, Mohammedia 20650, Morocco

² School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ 85287, USA

Appl. Sci. 2017, 7(8), 861; https://doi.org/10.3390/app7080861 - 21 Aug 2017

Cited by 32 | Viewed by 6214

Abstract

A modified mathematical model describing the human immunodeficiency virus (HIV) pathogenesis with cytotoxic T-lymphocytes (CTL) and infected cells in eclipse phase is presented and studied in this paper. The model under consideration also includes a saturated rate describing viral infection. First, the positivity [...] Read more.

A modified mathematical model describing the human immunodeficiency virus (HIV) pathogenesis with cytotoxic T-lymphocytes (CTL) and infected cells in eclipse phase is presented and studied in this paper. The model under consideration also includes a saturated rate describing viral infection. First, the positivity and boundedness of solutions for nonnegative initial data are proved. Next, the global stability of the disease free steady state and the endemic steady states are established depending on the basic reproduction number

R_{0}

and the CTL immune response reproduction number

R_{C T L}

. Moreover, numerical simulations are performed in order to show the numerical stability for each steady state and to support our theoretical findings. Our model based findings suggest that system immunity represented by CTL may control viral replication and reduce the infection. Full article

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16 pages, 1689 KiB

Open AccessArticle

Axial Fan Blade Vibration Assessment under Inlet Cross-Flow Conditions Using Laser Scanning Vibrometry

by Till Heinemann and Stefan Becker^*

Institute of Process Machinery and Systems Engineering, University of Erlangen-Nuremberg, Cauerstr. 4, 91058 Erlangen, Germany

Appl. Sci. 2017, 7(8), 862; https://doi.org/10.3390/app7080862 - 22 Aug 2017

Cited by 9 | Viewed by 9571

Abstract

In thermal power plants equipped with air-cooled condensers (ACCs), axial cooling fans operate under the influence of ambient flow fields. Under inlet cross-flow conditions, the resultant asymmetric flow field is known to introduce additional harmonic forces to the fan blades. This effect has [...] Read more.

In thermal power plants equipped with air-cooled condensers (ACCs), axial cooling fans operate under the influence of ambient flow fields. Under inlet cross-flow conditions, the resultant asymmetric flow field is known to introduce additional harmonic forces to the fan blades. This effect has previously only been studied numerically or by using blade-mounted strain gauges. For this study, laser scanning vibrometry (LSV) was used to assess fan blade vibration under inlet cross-flow conditions in an adapted fan test rig inside a wind tunnel test section. Two co-rotating laser beams scanned a low-pressure axial fan, resulting in spectral, phase-resolved surface vibration patterns of the fan blades. Two distinct operating points with flow coefficients of 0.17 and 0.28 were examined, with and without inlet cross-flow influence. While almost identical fan vibration patterns were found for both reference operating points, the overall blade vibration increased by 100% at the low fan flow rate as a result of cross-flow, and by 20% at the high fan flow rate. While numerically predicted natural frequency modes could be confirmed from experimental data as minor peaks in the vibration amplitude spectrum, they were not excited significantly by cross-flow. Instead, primarily higher rotation-rate harmonics were amplified; that is, a synchronous blade-tip flapping was strongly excited at the blade-pass frequency. Full article

(This article belongs to the Special Issue Laser Scanning)

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23 pages, 308 KiB

Open AccessPerspective

Paper and Fiber-Based Bio-Diagnostic Platforms: Current Challenges and Future Needs

by Samira Hosseini^1,2,*, Patricia Vázquez-Villegas¹ and Sergio O. Martínez-Chapa^1,*

¹ Escuela de Ingeniería y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, Monterrey 64849, NL, Mexico

² Research Laboratory of Electronics (RLE), Massachusetts Institute of Technology, Cambridge, MA 02139, USA

Appl. Sci. 2017, 7(8), 863; https://doi.org/10.3390/app7080863 - 22 Aug 2017

Cited by 27 | Viewed by 5737

Abstract

In this perspective article, some of the latest paper and fiber-based bio-analytical platforms are summarized, along with their fabrication strategies, the processing behind the product development, and the embedded systems in which paper or fiber materials were integrated. The article also reviews bio-recognition [...] Read more.

In this perspective article, some of the latest paper and fiber-based bio-analytical platforms are summarized, along with their fabrication strategies, the processing behind the product development, and the embedded systems in which paper or fiber materials were integrated. The article also reviews bio-recognition applications of paper/fiber-based devices, the detected analytes of interest, applied detection techniques, the related evaluation parameters, the type and duration of the assays, as well as the advantages and disadvantages of each technique. Moreover, some of the existing challenges of utilizing paper and/or fiber materials are discussed. These include control over the physical characteristics (porosity, permeability, wettability) and the chemical properties (surface functionality) of paper/fiber materials are discussed. Other aspects of the review focus on shelf life, the multi-functionality of the platforms, readout strategies, and other challenges that have to be addressed in order to obtain reliable detection outcomes. Full article

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Appl. Sci., Volume 7, Issue 8 (August 2017) – 114 articles

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