Applied Sciences

14 pages, 3459 KiB

Open AccessArticle

External Field Response and Applications of Metal Coated Hemispherical Janus Particles

by So Aizawa, Keisuke Seto and Eiji Tokunaga^*

Department of Physics, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan

Appl. Sci. 2018, 8(4), 653; https://doi.org/10.3390/app8040653 - 23 Apr 2018

Cited by 3 | Viewed by 4990

Abstract

Hemispherical Janus particles that were coated with silver or nickel on the equatorial plane of hemispherical polymer microparticles were prepared and dispersed in water and the responses to AC electric and stationary magnetic fields applied were investigated. Both of the particles are so [...] Read more.

Hemispherical Janus particles that were coated with silver or nickel on the equatorial plane of hemispherical polymer microparticles were prepared and dispersed in water and the responses to AC electric and stationary magnetic fields applied were investigated. Both of the particles are so oriented that the equatorial plane is parallel to the AC electric field, owing to electric-field induced dipole orientation, which is the response proportional to the quadratic electric field. The nickel coated particles are self-assembled to make a chain-like structure aligned in the direction of the stationary magnetic field. In addition, when both AC electric and stationary magnetic fields are applied, the orientation of a nickel-coated hemispherical particle is uniquely determined in such a way that the equatorial plane is parallel to both electric and magnetic fields. Because the particle is magnetized on the plane, its direction is reversed when the magnetic field is reversed, which is the response that is proportional to the magnetic field. Utilizing these features, mirrors are fabricated that can switch the transmittance and reflectance with electric and magnetic fields. Such features of the Janus particles as to be controlled by an electric and magnetic fields will find wide applications in the fields of microoptics and microfluidics. Full article

(This article belongs to the Section Optics and Lasers)

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Graphical abstract

13 pages, 878 KiB

Open AccessArticle

Rapid High-Resolution Wavenumber Extraction from Ultrasonic Guided Waves Using Adaptive Array Signal Processing

by Shigeaki Okumura^1,*, Vu-Hieu Nguyen², Hirofumi Taki³, Guillaume Haïat⁴, Salah Naili² and Toru Sato¹

¹ Graduate School of Informatics, Kyoto University, Kyoto 606-8501, Japan

² Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 94010 Créteil CEDEX, France

³ Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8575, Japan

⁴ CNRS, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 94010 Créteil CEDEX, France

Appl. Sci. 2018, 8(4), 652; https://doi.org/10.3390/app8040652 - 23 Apr 2018

Cited by 21 | Viewed by 4452

Abstract

Quantitative ultrasound techniques for assessment of bone quality have been attracting significant research attention. The axial transmission technique, which involves analysis of ultrasonic guided waves propagating along cortical bone, has been proposed for assessment of cortical bone quality. Because the frequency-dependent wavenumbers reflect [...] Read more.

Quantitative ultrasound techniques for assessment of bone quality have been attracting significant research attention. The axial transmission technique, which involves analysis of ultrasonic guided waves propagating along cortical bone, has been proposed for assessment of cortical bone quality. Because the frequency-dependent wavenumbers reflect the elastic parameters of the medium, high-resolution estimation of the wavenumbers is required at each frequency with low computational cost. We use an adaptive array signal processing method and propose a technique that can be used to estimate the numbers of propagation modes that exist at each frequency without the need for time-consuming calculations. An experimental study of 4-mm-thick copper and bone-mimicking plates showed that the proposed method estimated the wavenumbers accurately with estimation errors of less than 4% and a calculation time of less than 0.5 s when using a laptop computer. Full article

(This article belongs to the Special Issue Ultrasonic Guided Waves)

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15 pages, 9735 KiB

Open AccessArticle

On the Statistical Characterization of Lightning-Induced Voltages

by Amedeo Andreotti¹

, Fabio Mottola^2,*

, Antonio Pierno¹

and Daniela Proto¹

¹ University of Naples Federico II, Via Claudio 21, 80125 Naples, Italy

² University of Naples Parthenope, Centro Direzionale di Napoli, Is. C4, 80143 Naples, Italy

Appl. Sci. 2018, 8(4), 651; https://doi.org/10.3390/app8040651 - 23 Apr 2018

Cited by 12 | Viewed by 4258

Abstract

Protection against lightning-induced voltages is a particularly critical issue, especially for smart grids, due to the presence of electronic-based equipment, as well as control and monitoring devices. Analysis of the severity of the induced voltages is then imperative; on the other hand, the [...] Read more.

Protection against lightning-induced voltages is a particularly critical issue, especially for smart grids, due to the presence of electronic-based equipment, as well as control and monitoring devices. Analysis of the severity of the induced voltages is then imperative; on the other hand, the random nature of the lightning phenomenon cannot be disregarded. In this paper, the severity of lightning-induced voltage is analyzed by means of a probabilistic approach which, starting from closed-form solutions, uses a Monte Carlo procedure. Parametric distributions that best fit the distributions of the induced voltages are investigated as well. The results show that the lognormal and the generalized extreme value distributions are the best candidates. Full article

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22 pages, 11454 KiB

Open AccessArticle

Dynamic Response of a Long-Span Concrete-Filled Steel Tube Tied Arch Bridge and the Riding Comfort of Monorail Trains

by Hongye Gou^1,2,3

, Wen Zhou¹, Changwei Yang^1,2,*, Yi Bao³ and Qianhui Pu¹

¹ Department of Bridge Engineering, School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China

² Key Laboratory of High-Speed Railway Engineering, Ministry of Education, Chengdu 610031, China

³ Department of Civil, Architectural and Environmental Engineering, Missouri University of Science and Technology, Rolla, MO 65401, USA

Appl. Sci. 2018, 8(4), 650; https://doi.org/10.3390/app8040650 - 23 Apr 2018

Cited by 38 | Viewed by 8693

Abstract

In this study, a dynamic response analysis procedure is proposed and applied to investigate the dynamic responses of a straddle-type concrete-filled steel tube tied arch bridge under train and truck loadings. A numerical model of the coupled monorail train–bridge system is established to [...] Read more.

In this study, a dynamic response analysis procedure is proposed and applied to investigate the dynamic responses of a straddle-type concrete-filled steel tube tied arch bridge under train and truck loadings. A numerical model of the coupled monorail train–bridge system is established to investigate the dynamic behaviors of the bridge under moving trains. A refined three-dimensional finite element model is built for the bridge and a 15 degrees-of-freedom vehicle model is presented for the train. The numerical model is validated using in-situ test results and then used to analyze the dynamic displacement and acceleration of the bridge and the trains on the bridge. Based on the simulation results, the impact factor of the bridge is investigated and the riding comfort of the trains is evaluated. The investigation results show that the impact factor of vehicle loads reaches the maximum value when the resonance of the bridge is induced by the moving vehicles. The effect of train braking predominates the longitudinal vibration of the bridge but is negligible in the transverse and vertical directions. The vehicle speed is the dominating factor for the riding comfort of the train. Full article

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22 pages, 11977 KiB

Open AccessArticle

Lyapunov Equivalent Representation Form of Forced, Damped, Nonlinear, Two Degree-of-Freedom Systems

by Alex Elías-Zúñiga^1,*

, Luis M. Palacios-Pineda²

, Daniel Olvera-Trejo¹ and Oscar Martínez-Romero¹

¹ Escuela de Ingeniería y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, Monterrey, N.L., C.P. 64849, Mexico

² División de Estudios de Posgrado e Investigación, Tecnológico Nacional de México/Instituto Tecnológico de Pachuca, Carr. México-Pachuca Km 87.5, Pachuca, Hidalgo, C.P. 42080, Mexico

Appl. Sci. 2018, 8(4), 649; https://doi.org/10.3390/app8040649 - 21 Apr 2018

Cited by 11 | Viewed by 4364

Abstract

The aim of this paper focuses on finding equivalent representation forms of forced, damped, two degree-of-freedom, nonlinear systems in the sense of Lyapunov by using a nonlinear transformation approach that provides decoupled, forced, damped, nonlinear equations of the Duffing type, under the assumption [...] Read more.

The aim of this paper focuses on finding equivalent representation forms of forced, damped, two degree-of-freedom, nonlinear systems in the sense of Lyapunov by using a nonlinear transformation approach that provides decoupled, forced, damped, nonlinear equations of the Duffing type, under the assumption that the driving frequency and the external forces are equal in both systems. The values of Lyapunov characteristic exponents (LCEs), Lyapunov largest exponents (LLE), and time-amplitude and frequency-amplitude curves computed from numerical integration solutions, indicate that the decoupled Duffing-type equations are equivalent, in the sense of Lyapunov, to the original dynamic system, since both set of motion equations tend to have the same qualitative and quantitative behaviors. Full article

(This article belongs to the Section Mechanical Engineering)

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23 pages, 2160 KiB

Open AccessArticle

Energy Management Scheme for an EV Smart Charger V2G/G2V Application with an EV Power Allocation Technique and Voltage Regulation

by Saad Ullah Khan¹

, Khawaja Khalid Mehmood¹

, Zunaib Maqsood Haider¹, Syed Basit Ali Bukhari¹

, Soon-Jeong Lee², Muhammad Kashif Rafique¹ and Chul-Hwan Kim^1,*

¹ College of Information and Communication Engineering, Sungkyunkwan University, Suwon 16419, Korea

² KEPCO Economy and Management Research Institute, Naju 58217, Korea

Appl. Sci. 2018, 8(4), 648; https://doi.org/10.3390/app8040648 - 21 Apr 2018

Cited by 51 | Viewed by 10224

Abstract

The increasing penetration of electric vehicles (EVs) in the distribution grid has established them as a prospective resource for ancillary services. These services require adequate control strategies for prompt and efficient operation. In this study, an energy management scheme (EMS) has been proposed [...] Read more.

The increasing penetration of electric vehicles (EVs) in the distribution grid has established them as a prospective resource for ancillary services. These services require adequate control strategies for prompt and efficient operation. In this study, an energy management scheme (EMS) has been proposed to employ an off-board EV smart charger to support the grid during short-term variance of renewables and reactive load onset. The scheme operates by calculating power references for the charger instantaneously. The EMS incorporates a proportional power division methodology, proposed to allocate power references to the individual EVs connected to the charger DC-bus. This methodology considers the state-of-charge and battery sizes of the EVs, and it can aggregate energy from various types of EVs. The proposed scheme is compared with another power allocation method, and the entire EMS is tested under the scenarios of power mismatch and voltage sag/swell events. The results show that the proposed scheme achieves the goal of the aggregation of EVs at the charger level to support the grid. The EMS also fulfills the objectives of voltage regulation and four-quadrant operation of the smart charger. Full article

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

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18 pages, 4663 KiB

Open AccessArticle

Novel Guidance CPS Based on the FatBeacon Protocol

by Moisés Lodeiro-Santiago^*, Iván Santos-González, Cándido Caballero-Gil

, Pino Caballero-Gil

and Félix Herrera-Priano

Departamento de Ingeniería Informática y de Sistemas, Universidad de La Laguna, Tenerife 38200, Spain

Appl. Sci. 2018, 8(4), 647; https://doi.org/10.3390/app8040647 - 20 Apr 2018

Cited by 4 | Viewed by 4199

Abstract

Throughout this work, the use of a new technology is proposed to give an innovative solution to the problem of indoor and outdoor positioning and a guidance system in areas where there is no coverage of Internet or global positioning systems. This novel [...] Read more.

Throughout this work, the use of a new technology is proposed to give an innovative solution to the problem of indoor and outdoor positioning and a guidance system in areas where there is no coverage of Internet or global positioning systems. This novel solution is based on the Bluetooth protocol called FatBeacon, created by Google, which can be used in places such as subway stations located below ground, outdoor areas where even 2G coverage is unreachable or simply as an alternative to current technologies that may require an additional cost, such as the Internet in some countries. In particular, this work describes a new solution for supporting tourism called Smart Tourism for which an interactive and non-intrusive guidance application based on the FatBeacon protocol is presented. The developed application informs the users about the way to reach their destination without getting lost and can be used to obtain user data tracking anonymously. In this way, the cooperation between the different systems and components of the scheme creates a distributed ecosystem that is independent of an Internet connection. Since no FatBeacon implementations can be found yet, an experimental implementation was developed to test the proposal, and the obtained results are promising. Full article

(This article belongs to the Special Issue Security and Privacy for Cyber Physical Systems)

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32 pages, 9373 KiB

Open AccessArticle

Proposing Enhanced Feature Engineering and a Selection Model for Machine Learning Processes

by Muhammad Fahim Uddin^1,*, Jeongkyu Lee¹, Syed Rizvi² and Samir Hamada³

¹ School of Computer Science and Engineering, University of Bridgeport, 126 Park Ave, Bridgeport, CT 06604, USA

² Information Science and Technologies, Penn State University, 3000 Ivyside Park, Altoona, PA 16601, USA

³ Computer Systems, School of Business, Farmingdale State College, 2350 Broadhollow Rd, Farmingdale, NY 11735, USA

Appl. Sci. 2018, 8(4), 646; https://doi.org/10.3390/app8040646 - 20 Apr 2018

Cited by 46 | Viewed by 9844

Abstract

Machine Learning (ML) requires a certain number of features (i.e., attributes) to train the model. One of the main challenges is to determine the right number and the type of such features out of the given dataset’s attributes. It is not uncommon for [...] Read more.

Machine Learning (ML) requires a certain number of features (i.e., attributes) to train the model. One of the main challenges is to determine the right number and the type of such features out of the given dataset’s attributes. It is not uncommon for the ML process to use dataset of available features without computing the predictive value of each. Such an approach makes the process vulnerable to overfit, predictive errors, bias, and poor generalization. Each feature in the dataset has either a unique predictive value, redundant, or irrelevant value. However, the key to better accuracy and fitting for ML is to identify the optimum set (i.e., grouping) of the right feature set with the finest matching of the feature’s value. This paper proposes a novel approach to enhance the Feature Engineering and Selection (eFES) Optimization process in ML. eFES is built using a unique scheme to regulate error bounds and parallelize the addition and removal of a feature during training. eFES also invents local gain (LG) and global gain (GG) functions using 3D visualizing techniques to assist the feature grouping function (FGF). FGF scores and optimizes the participating feature, so the ML process can evolve into deciding which features to accept or reject for improved generalization of the model. To support the proposed model, this paper presents mathematical models, illustrations, algorithms, and experimental results. Miscellaneous datasets are used to validate the model building process in Python, C#, and R languages. Results show the promising state of eFES as compared to the traditional feature selection process. Full article

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

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20 pages, 12320 KiB

Open AccessReview

A Review of MEMS Scale Piezoelectric Energy Harvester

by Wenchao Tian, Zongyu Ling^*, Wenbo Yu

and Jing Shi

School of Electro-Mechanical Engineering, Xidian University, Number 2 Taibai South Road, Xi’an 710071, China

Appl. Sci. 2018, 8(4), 645; https://doi.org/10.3390/app8040645 - 20 Apr 2018

Cited by 78 | Viewed by 10750

Abstract

Piezoelectric energy harvester (PEH) is emerging as a novel device which can convert mechanical energy into electrical energy. It is mainly used to collect ambient vibration energy to power sensors, chips and some other small applications. This paper first introduces the working principle [...] Read more.

Piezoelectric energy harvester (PEH) is emerging as a novel device which can convert mechanical energy into electrical energy. It is mainly used to collect ambient vibration energy to power sensors, chips and some other small applications. This paper first introduces the working principle of PEH. Then, the paper elaborates the research progress of PEH from three aspects: piezoelectric materials, piezoelectric modes and energy harvester structures. Piezoelectric material is the core of the PEH. The piezoelectric and mechanical properties of piezoelectric material determine its application in energy harvesting. There are three piezoelectric modes, d₃₁, d₃₃ and d₁₅, the choice of which influences the maximum output voltage and power. Matching the external excitation frequency maximizes the conversion efficiency of the energy harvester. There are three approaches proposed in this paper to optimize the PEH’s structure and match the external excitation frequency, i.e., adjusting the resonant frequency, frequency up-converting and broadening the frequency bandwidth. In addition, harvesting maximum output power from the PEH requires impedance matching. Finally, this paper analyzes the above content and predicts PEH’s future development direction. Full article

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

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10 pages, 5501 KiB

Open AccessArticle

Camera Calibration with Phase-Shifting Wedge Grating Array

by Jiayuan Tao, Yuwei Wang, Bolin Cai and Keyi Wang^*

Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China

Appl. Sci. 2018, 8(4), 644; https://doi.org/10.3390/app8040644 - 20 Apr 2018

Cited by 8 | Viewed by 4908

Abstract

Planar targets with known features have been widely used for camera calibration in various vision systems. This paper utilizes phase-shifting wedge grating (PWG) arrays as an active calibration target. Features points are encoded into the carrier phase, which can be accurately calculated using [...] Read more.

Planar targets with known features have been widely used for camera calibration in various vision systems. This paper utilizes phase-shifting wedge grating (PWG) arrays as an active calibration target. Features points are encoded into the carrier phase, which can be accurately calculated using the phase-shifting algorithm. The 2π-phase points are roughly extracted with edge detection and then optimized by windowed bicubic fitting with sub-pixel accuracy. Two 2π-phase lines for each PWG are obtained using linear fitting method. The PWG centers that are used as feature points are detected through computing the intersections of 2π-phase lines. Experiment results indicate that the proposed method is accurate and reliable. Full article

(This article belongs to the Section Optics and Lasers)

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6 pages, 2830 KiB

Open AccessCommunication

Carbon Nanotube Mode-Locked Fiber Laser Generating Cylindrical Vector Beams with a Two-Mode Fiber Bragg Grating

by Yu Cai¹, Jiaojiao Zhang¹, Changle Wang², Lin Zhang² and Zuxing Zhang^1,*

¹ Advanced Photonic Technology Lab, College of Electronic and Optical Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China

² Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET, UK

Appl. Sci. 2018, 8(4), 643; https://doi.org/10.3390/app8040643 - 20 Apr 2018

Cited by 2 | Viewed by 4191

Abstract

We propose and demonstrate a compact all-fiber laser generating cylindrical vector beam (CVB) using carbon nanotubes as the saturable absorber for mode-locking and a two-mode fiber Bragg grating (TM-FBG) as the mode discriminator. Both radially and azimuthally polarized beams with a polarization purity [...] Read more.

We propose and demonstrate a compact all-fiber laser generating cylindrical vector beam (CVB) using carbon nanotubes as the saturable absorber for mode-locking and a two-mode fiber Bragg grating (TM-FBG) as the mode discriminator. Both radially and azimuthally polarized beams with a polarization purity of 90% were obtained by simply adjusting the polarization controllers. The CVB mode-locked fiber laser operates at 1552.9 nm with a 3-dB line width of less than 0.02 nm, generating ns CVB pulses. The all-fiber CVB laser may have potential applications from fundamental research to practical applications, such as particle capture, high-resolution measurement and material processing. Full article

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

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13 pages, 4401 KiB

Open AccessFeature PaperArticle

Stability Analysis of Stagnation-Point Flow in a Nanofluid over a Stretching/Shrinking Sheet with Second-Order Slip, Soret and Dufour Effects: A Revised Model

by Najwa Najib^*

, Norfifah Bachok, Norihan Md Arifin and Fadzilah Md Ali

Department of Mathematics and Institute for Mathematical Research, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia

Appl. Sci. 2018, 8(4), 642; https://doi.org/10.3390/app8040642 - 20 Apr 2018

Cited by 32 | Viewed by 5206

Abstract

The mathematical model of the two-dimensional steady stagnation-point flow over a stretching or shrinking sheet of nanofluid in the presence of the Soret and Dufour effects and of second-order slip at the boundary was considered in this paper. The partial differential equations were [...] Read more.

The mathematical model of the two-dimensional steady stagnation-point flow over a stretching or shrinking sheet of nanofluid in the presence of the Soret and Dufour effects and of second-order slip at the boundary was considered in this paper. The partial differential equations were transformed into the ordinary differential equations by applying a suitable similarity transformation. The numerical results were obtained by using bvp4c codes in Matlab. The skin friction coefficient, heat transfer coefficient, mass transfer coefficient, as well as the velocity, temperature, and concentration profiles were presented graphically for different values of slip parameters, Soret effect, Dufour effect, Brownian motion parameter, and thermophoresis parameter. A dual solution was obtained in this present paper. The presence of the slip parameters (first- and second-order slip parameters) was found to expand the range of solutions. However, the presence of the slip parameters led to a decrease in the skin friction coefficient, whereas the heat transfer coefficient increased. Besides that, a larger Soret effect (smallest Dufour effect) led to the decrement of the heat transfer coefficient. The effects of the Brownian motion and thermophoresis parameters on the heat transfer coefficient were also studied in this paper. A stability analysis was performed in this paper to verify the stability of the solutions obtained. Full article

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

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18 pages, 3854 KiB

Open AccessArticle

Power System Voltage Correction Scheme Based on Adaptive Horizon Model Predictive Control

by Yan Zhang^1,*, Meng Liu¹, Wen Zhang², Wenchuan Sun³, Xingwang Hu³ and Gang Kong¹

¹ State Grid Shandong Electric Power Research Institute, Jinan 250003, China

² Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education, Shandong University, Jinan 250061, China

³ State Grid Shandong Electric Power Company, Jinan 250001, China

Appl. Sci. 2018, 8(4), 641; https://doi.org/10.3390/app8040641 - 20 Apr 2018

Cited by 2 | Viewed by 4142

Abstract

Model predictive control (MPC) is commonly used to compensate for modeling inaccuracies and measurement noise in voltage control problems. The length of the prediction horizon and control horizon of a MPC-based method has significant impact on the control performances. In existing relevant works, [...] Read more.

Model predictive control (MPC) is commonly used to compensate for modeling inaccuracies and measurement noise in voltage control problems. The length of the prediction horizon and control horizon of a MPC-based method has significant impact on the control performances. In existing relevant works, those horizon parameters are determined off-line based on experience or enumeration, and keeps constant during the entire receding-horizon optimization process. This paper presents a system voltage correction scheme based on adaptive horizon model predictive control (AH-MPC). The reactive power compensation and voltage regulation devices are coordinated to maintain the system voltages within a desired range. An evaluation index is proposed to determine the horizon parameters, which reflects the maximum voltage regulation ability with the current parameter configuration. Within each sampling interval, the horizon parameters are updated according to the evaluation index and real-time measurements periodically, which comprehensively considers the system uncertainties and voltage recovery speed, and the computational effort is remarkably reduced. The validation and effectiveness of the proposed method is verified by the simulation analysis on the test system. Full article

(This article belongs to the Special Issue Smart Grid and Smart Cities Activities)

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12 pages, 10870 KiB

Open AccessArticle

Fusion of Spectra and Texture Data of Hyperspectral Imaging for the Prediction of the Water-Holding Capacity of Fresh Chicken Breast Filets

by Yi Yang¹, Wei Wang^1,*

, Hong Zhuang², Seung-Chul Yoon² and Hongzhe Jiang¹

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

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

Appl. Sci. 2018, 8(4), 640; https://doi.org/10.3390/app8040640 - 20 Apr 2018

Cited by 34 | Viewed by 5437

Abstract

This study investigated the fusion of spectra and texture data of hyperspectral imaging (HSI, 1000–2500 nm) for predicting the water-holding capacity (WHC) of intact, fresh chicken breast filets. Three physical and chemical indicators—drip loss, expressible fluid, and salt-induced water gain—were measured to be [...] Read more.

This study investigated the fusion of spectra and texture data of hyperspectral imaging (HSI, 1000–2500 nm) for predicting the water-holding capacity (WHC) of intact, fresh chicken breast filets. Three physical and chemical indicators—drip loss, expressible fluid, and salt-induced water gain—were measured to be different WHC references of chicken meat. Different partial least squares regression (PLSR) models were established with corresponding input variables including the full spectra, key wavelengths, and texture variables, as well as the fusion data of key wavelengths and the corresponding texture variables, respectively. The results demonstrated that for drip loss and expressible fluid, texture data was an effective supplement to spectra data, and fusion data as an input variable could effectively improve the predictive ability of the independent prediction set (Rp = 0.80, RMSEp = 0.80; Rp = 0.56, RMSEp = 2.10). While the best model to predict salt-induced water gain was based on key wavelengths (Rp = 0.69, RMSEp = 18.04), this was mainly because salt-induced water gain was measured on mince samples, which lacked the important physical structure to represent the texture information of meat. Our results of this study demonstrated the potential to further improve the evaluation of the WHC of chicken meat by HSI. Full article

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

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17 pages, 7586 KiB

Open AccessArticle

Development of Proportional Pressure Control Valve for Hydraulic Braking Actuator of Automobile ABS

by Che-Pin Chen and Mao-Hsiung Chiang^*

Department of Engineering Science and Ocean Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei City 106, Taiwan

Appl. Sci. 2018, 8(4), 639; https://doi.org/10.3390/app8040639 - 20 Apr 2018

Cited by 18 | Viewed by 11942

Abstract

This research developed a novel proportional pressure control valve for an automobile hydraulic braking actuator. It also analyzed and simulated solenoid force of the control valves, and the pressure relief capability test of electromagnetic thrust with the proportional valve body. Considering the high [...] Read more.

This research developed a novel proportional pressure control valve for an automobile hydraulic braking actuator. It also analyzed and simulated solenoid force of the control valves, and the pressure relief capability test of electromagnetic thrust with the proportional valve body. Considering the high controllability and ease of production, the driver of this proportional valve was designed with a small volume and powerful solenoid force to control braking pressure and flow. Since the proportional valve can have closed-loop control, the proportional valve can replace a conventional solenoid valve in current brake actuators. With the proportional valve controlling braking and pressure relief mode, it can narrow the space of hydraulic braking actuator, and precisely control braking force to achieve safety objectives. Finally, the proposed novel proportional pressure control valve of an automobile hydraulic braking actuator was implemented and verified experimentally. Full article

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

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15 pages, 5871 KiB

Open AccessArticle

Trouton’s Rule for Vapor Sorption in Solids

by Ard-Jan De Jong^1,* and Hartmut Fischer²

¹ TNO, Leeghwaterstraat 46, 2628 CA Delft, The Netherlands

² TNO, High Tech Campus 5, 5656 AE Eindhoven, The Netherlands

Appl. Sci. 2018, 8(4), 638; https://doi.org/10.3390/app8040638 - 20 Apr 2018

Cited by 3 | Viewed by 7156

Abstract

Hygroscopic salts exhibiting fast and reversible hydration are promising systems for seasonal heat storage, providing the possibility of storing excess solar energy from the warm season for later use during the cold season. For heat storage, the salt is dehydrated with the available [...] Read more.

Hygroscopic salts exhibiting fast and reversible hydration are promising systems for seasonal heat storage, providing the possibility of storing excess solar energy from the warm season for later use during the cold season. For heat storage, the salt is dehydrated with the available heat, and for heat recovery, the salt is rehydrated. There are many salt hydration transitions and for selecting the most suited ones with respect to the envisaged use cases, temperatures of dehydration and rehydration are needed, as well as the heat storage density. Estimation of these properties requires entropy and enthalpy changes of the transitions. Collections of hydration entropies and enthalpies have been published, but not all data seems reliable for various reasons, and it is often hard to access original sources and experimental conditions. For the necessary data validation, we propose the use of Trouton’s rule, known to hold for the evaporation of classes of fluids. Besides data validation, Trouton’s rule is useful for predicting heat storage densities and vapor pressures when only the transition enthalpy is known. We discuss the validity of Trouton’s rule for salt hydration and ammoniation transitions by theoretical and experimental evidence on the available extensive data collections. Full article

(This article belongs to the Special Issue Materials for Thermal Energy Storage)

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18 pages, 32924 KiB

Open AccessArticle

Multi-Plane Ultrafast Compound 3D Strain Imaging: Experimental Validation in a Carotid Bifurcation Phantom

by Stein Fekkes^*

, Anne E. C. M. Saris

, Jan Menssen, Maartje M. Nillesen, Hendrik H. G. Hansen

and Chris L. De Korte

Medical Ultrasound Imaging Center, Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen 6500 HB, The Netherlands

Appl. Sci. 2018, 8(4), 637; https://doi.org/10.3390/app8040637 - 20 Apr 2018

Cited by 9 | Viewed by 4741

Abstract

Strain imaging of the carotid artery (CA) has demonstrated to be a technique capable of identifying plaque composition. This study assesses the performance of volumetric strain imaging derived from multi-plane acquisitions with a single transducer, with and without displacement compounding. These methods were [...] Read more.

Strain imaging of the carotid artery (CA) has demonstrated to be a technique capable of identifying plaque composition. This study assesses the performance of volumetric strain imaging derived from multi-plane acquisitions with a single transducer, with and without displacement compounding. These methods were compared to a reference method using two orthogonally placed transducers. A polyvinyl alcohol phantom was created resembling a stenotic CA bifurcation. A realistic pulsatile flow was imposed on the phantom, resulting in fluid pressures inducing 10% strains. Two orthogonally aligned linear array transducers were connected to two Verasonics systems and fixed in a translation stage. For 120 equally spaced elevational positions, ultrasound series were acquired for a complete cardiac cycle and synchronized using a trigger. Each series consisted of ultrafast plane-wave acquisitions at 3 alternating angles. Inter-frame displacements were estimated using a 3D cross-correlation-based tracking algorithm. Horizontal displacements were acquired using the single probe lateral displacement estimate, the single probe compounded by axial displacement estimates obtained at angles of 19.47 and −19.47 degrees, and the dual probe registered axial displacement estimate. After 3D tracking, least squares strain estimations were performed to compare compressive and tensile principal strains in 3D for all methods. The compounding technique clearly outperformed the zero-degree method for the complete cardiac cycle and resulted in more accurate 3D strain estimates. Full article

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

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19 pages, 6961 KiB

Open AccessArticle

Forecasting of Power Grid Investment in China Based on Support Vector Machine Optimized by Differential Evolution Algorithm and Grey Wolf Optimization Algorithm

by Shuyu Dai^1,2,*, Dongxiao Niu^1,2 and Yaru Han^1,2

¹ School of Economics and Management, North China Electric Power University, Beijing 102206, China

² Beijing Key Laboratory of New Energy and Low-Carbon Development, North China Electric Power University, Beijing 102206, China

Appl. Sci. 2018, 8(4), 636; https://doi.org/10.3390/app8040636 - 19 Apr 2018

Cited by 40 | Viewed by 5916

Abstract

In recent years, the construction of China’s power grid has experienced rapid development, and its scale has leaped into the first place in the world. Accurate and effective prediction of power grid investment can not only help pool funds and rationally arrange investment [...] Read more.

In recent years, the construction of China’s power grid has experienced rapid development, and its scale has leaped into the first place in the world. Accurate and effective prediction of power grid investment can not only help pool funds and rationally arrange investment in power grid construction, but also reduce capital costs and economic risks, which plays a crucial role in promoting power grid investment planning and construction process. In order to forecast the power grid investment of China accurately, firstly on the basis of analyzing the influencing factors of power grid investment, the influencing factors system for China’s power grid investment forecasting is constructed in this article. The method of grey relational analysis is used for screening the main influencing factors as the prediction model input. Then, a novel power grid investment prediction model based on DE-GWO-SVM (support vector machine optimized by differential evolution and grey wolf optimization) algorithm is proposed. Next, two cases are taken for empirical analysis to prove that the DE-GWO-SVM model has strong generalization capacity and has achieved a good prediction effect for power grid investment forecasting in China. Finally, the DE-GWO-SVM model is adopted to forecast power grid investment in China from 2018 to 2022. Full article

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

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11 pages, 27259 KiB

Open AccessArticle

Histological and Bone Morphometric Evaluation of Osseointegration Aspects by Alkali Hydrothermally-Treated Implants

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

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

Appl. Sci. 2018, 8(4), 635; https://doi.org/10.3390/app8040635 - 19 Apr 2018

Cited by 6 | Viewed by 4280

Abstract

The purpose of this study was to investigate the osseointegration aspects of alkali-treated implants by histological and bone morphometric evaluations. Titanium implants (control) and alkali hydrothermally-treated titanium implants were used. Samples were evaluated by surface structure observation and wettability tests. Both implants were [...] Read more.

The purpose of this study was to investigate the osseointegration aspects of alkali-treated implants by histological and bone morphometric evaluations. Titanium implants (control) and alkali hydrothermally-treated titanium implants were used. Samples were evaluated by surface structure observation and wettability tests. Both implants were placed into the femurs of five rabbits, and osseointegration was assessed by measurement of removal torque (RT), bone–implant contact ratio (BIC), and bone tissue area ratio (BTA). Measurements were performed at the whole portion around the implant, the cortical bone portion, and the bone marrow portion. The surface structure of alkali-group showed nanoscale pores and super hydrophilicity. RT, BIC, and BTA values of alkali-group were significantly higher than those of control-group at the whole portion. In the cortical bone portion, the BIC value was higher in the alkali-group than in the control-group, and BTA showed no significant difference between groups. In the bone marrow portion, even though no significant difference between control and alkali groups, the latter had higher ratio of BIC than the former. These results indicate that alkali treated implants enhance bone integration in areas where the implant is in contact with bone, and may promote osteoinduction in the non-bone marrow portion. Full article

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

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11 pages, 2317 KiB

Open AccessArticle

Enhancement of Neuroprotective Effects of Spirulina platensis Extract from a High-Pressure Homogenization Process

by Woon Yong Choi¹ and Hyeon Yong Lee^2,*

¹ Department of Medical Biomaterials Engineering, Kangwon National University, Chuncheon 200-701, Korea

² Department of Food Science and Engineering, Seowon University, Cheongju 361-742, Korea

Appl. Sci. 2018, 8(4), 634; https://doi.org/10.3390/app8040634 - 19 Apr 2018

Cited by 10 | Viewed by 4127

Abstract

This study is the first to show that a simple high-pressure homogenization process (HP) could extract very heat-sensitive chlorophyll from a marine alga, Spirulina platensis. Up to 9.85 mg/g was produced at an optimal input pressure of 650 bar with a shear [...] Read more.

This study is the first to show that a simple high-pressure homogenization process (HP) could extract very heat-sensitive chlorophyll from a marine alga, Spirulina platensis. Up to 9.85 mg/g was produced at an optimal input pressure of 650 bar with a shear stress of approximately 20,000 (1/s) compared to 5.27 mg/g from conventional 70% ethanol extraction (EE) at 40 °C for 24 h. However, a higher input pressure did not increase the extraction yield and in fact decreased it, possibly due to the destruction of chlorophyll a at a high shear stress of approximately 50,000 (1/s) under 1370 bar of input pressure. Chlorophyll a and other components of the extract had additive effects, showing higher antioxidant activities of ca. 56% of DPPH radical scavenging activities than 10 μg/mL chlorophyll a alone, which corresponded to the same chlorophyll a content that existed in the extract. It was also confirmed that the high antioxidant activities of the HP extract reduced the production of reactive oxygen species (ROS) from glutamate-induced HT22 cells, which resulted in increased neuroprotective activity compared to EE and even chlorophyll a alone, in addition to effectively reducing the release of Ca²⁺ from nerve cells. Full article

(This article belongs to the Special Issue Acoustic and Hydrodynamic Effects in Food Processing)

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19 pages, 5055 KiB

Open AccessArticle

Experimental Investigation of the Creep Behaviour of Coal by Monitoring Changes of Acoustic Properties

by Sen Yang^1,2

, Nong Zhang^1,*

, Xiaowei Feng¹ and Jiaguang Kan¹

¹ Key Laboratory of Deep Coal Resource Mining, Ministry of Education of China, School of Mines, China University of Mining and Technology, Xuzhou 221116, China

² Department of Energy and Mineral Engineering, G3 Center and Energy Institute, The Pennsylvania State University, University Park, PA 16802, USA

Appl. Sci. 2018, 8(4), 633; https://doi.org/10.3390/app8040633 - 19 Apr 2018

Cited by 7 | Viewed by 4095

Abstract

Time-dependent deformation of coal is a major concern for deep coal mining. When experiencing high stress conditions, the enhanced time-dependent deformation of coal will become a very possible factor to trigger the violent failure of underground openings. For this study, the inner structural [...] Read more.

Time-dependent deformation of coal is a major concern for deep coal mining. When experiencing high stress conditions, the enhanced time-dependent deformation of coal will become a very possible factor to trigger the violent failure of underground openings. For this study, the inner structural variation of an extremely inhomogeneous coal subjected to incremental creep stress has been experimentally investigated by monitoring both the macroscopic deformation and acoustic property. Results show the following: (1) The pronounced inhomogeneity of coal induces considerable irregularities in creep strain data collected during the increase of stress level. These flawed data highlight the shortcomings of conventional strain-time relationship experiments for deciphering the mechanisms that control creep; (2) The mechanical response of samples under creep compression is the result of competition between compaction and cracking. Cracking deteriorates the structure and increases the ultrasonic attenuation, whilst the compaction causes the densification along the axial axis and reduces attenuation; (3) Long-term creep involves multiple structural deformations that alter the internal structure of the coal. This results in fluctuations of the ultrasonic velocities and their dynamic moduli; (4) During uploading phase of short term creep, vertical cracks develop and transform the sample into a structure consisting of separated columns. Further deterioration of the coal increases the possibility of tensile and shear failure of individual columns, which can trigger the violent collapse of an already fragile structure. Full article

(This article belongs to the Section Acoustics and Vibrations)

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6 pages, 18867 KiB

Open AccessArticle

New Instrument for Oral Hygiene of Children with Cleft Lip and Palate

by Rita Rodrigues^1,2

, Maria Helena Fernandes^1,3

, António Bessa Monteiro⁴, Rowney Furfuro⁴, Cátia Carvalho Silva², César Soares⁵

, Ricardo Vardasca⁵

, Joaquim Mendes^5,*

and Maria Conceição Manso^3,6

¹ Faculty of Dentistry, University of Porto, R. Dr. Manuel Pereira da Silva, 93, 4200-393 Porto, Portugal

² Faculty of Health Sciences, University Fernando Pessoa, Praça 9 de Abril, 349, 4249-004 Porto, Portugal

³ Associated Laboratory for Green Chemistry (LAQV/REQUIMTE), University of Porto, 4051-401 Porto, Portugal

⁴ Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, s/n, 4200-319 Porto, Portugal

⁵ Faculty of Engineering, University of Porto, R. Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal

⁶ Faculty of Health Sciences, University Fernando Pessoa, Fernando Pessoa Energy, Environment and Health Research Unit (FP-ENAS), Praça de 9 de Abril, 349, 4249-004 Porto, Portugal

Appl. Sci. 2018, 8(4), 576; https://doi.org/10.3390/app8040576 - 19 Apr 2018

Cited by 2 | Viewed by 7683

Abstract

Patients with cleft lip and palate (CLP) have several oral alterations that make the removal of bacterial plaque in the cleft area difficult, which is the main cause of the high incidence of oral health problems. The aim of this study is to [...] Read more.

Patients with cleft lip and palate (CLP) have several oral alterations that make the removal of bacterial plaque in the cleft area difficult, which is the main cause of the high incidence of oral health problems. The aim of this study is to develop a toothbrush especially designed to perform the hygiene of the cleft area. This device, called Cleft Toothbrush, is an add-on to a conventional toothbrush to clean hard-to-reach areas that are not accessible by using conventional brush shapes. The design was made in SOLIDWORKS® (Waltham, MA, USA) 3D and a sample of this device was produced by CURAPROX (Kriens, Switzerland). The efficacy of the Cleft Toothbrush was tested in a preliminary study performed in a four years old child with CLP, compared to that of a conventional toothbrush. A significantly higher reduction of the bacterial plaque was achieved with the Cleft Toothbrush. The child’s parents also felt more confident with this device, as it deals better with sensitive areas, as it did not hurt the child. This innovative toothbrush adapter appears to greatly improve the cleaning areas of high bacterial plaque retention in patients with CLP, together with excellent acceptance. Full article

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

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14 pages, 2156 KiB

Open AccessArticle

A Novel Swarm Optimisation Algorithm Based on a Mixed-Distribution Model

by Xiaoming Zhang^1,*

, Tinghao Feng², Qingsong Niu³ and Xijin Deng³

¹ School of Information and Computers, Anhui Agricultural University, Hefei 230031, China

² iFlytek Co. Ltd., Hefei 230088, China

³ Qinghai Institute of Science and Technology Information, Xining 810008, China

Appl. Sci. 2018, 8(4), 632; https://doi.org/10.3390/app8040632 - 18 Apr 2018

Cited by 9 | Viewed by 3961

Abstract

Many swarm intelligence optimisation algorithms have been inspired by the collective behaviour of natural and artificial, decentralised, self-organised systems. Swarm intelligence optimisation algorithms have unique advantages in solving certain complex problems that cannot be easily solved by traditional optimisation algorithms. Inspired by the [...] Read more.

Many swarm intelligence optimisation algorithms have been inspired by the collective behaviour of natural and artificial, decentralised, self-organised systems. Swarm intelligence optimisation algorithms have unique advantages in solving certain complex problems that cannot be easily solved by traditional optimisation algorithms. Inspired by the adaptive phenomena of plants, a novel evolutionary algorithm named the bean optimisation algorithm (BOA) is proposed, which combines natural evolutionary tactics and limited random searches. It demonstrates stable behaviour in experiments and is a promising alternative to existing optimisation methods for engineering applications. A novel distribution model for BOA is built through research and study on the relevant research results of biostatistics. This model is based on a combination of the negative binomial and normal distributions, and the resulting algorithm is called NBOA. To validate NBOA, function optimisation experiments are carried out, which include ten typical benchmark functions. The results indicate that NBOA performs better than particle swarm optimisation (PSO) and BOA. We also investigate the characteristics of NBOA and conduct a contrast analysis to verify our conclusions about the relationship between its parameters and its performance. Full article

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14 pages, 5225 KiB

Open AccessArticle

Adaptive CoMP with Spatial Phase Coding for Interference Mitigation in the Heterogeneous Network

by Won-Chang Kim, Min-Jae Paek, Jae-Hyun Ro and Hyoung-Kyu Song^*

uT Communication Research Institute, Sejong University, Gunja-dong 98, Gwangjin-gu, Seoul 05006, Korea

Appl. Sci. 2018, 8(4), 631; https://doi.org/10.3390/app8040631 - 18 Apr 2018

Cited by 4 | Viewed by 3442

Abstract

This paper proposes an adaptive coordinated multi point (CoMP) scheme using pre-coding in order to improve the reliability of wireless communication systems based on orthogonal frequency division multiplexing (OFDM). In the conventional scheme, the received signal to noise ratio (SNR) of the mobile [...] Read more.

This paper proposes an adaptive coordinated multi point (CoMP) scheme using pre-coding in order to improve the reliability of wireless communication systems based on orthogonal frequency division multiplexing (OFDM). In the conventional scheme, the received signal to noise ratio (SNR) of the mobile is degraded due to the interference signal. Therefore, the bit error rate (BER) performance is degraded, as is, the reliability of the system, due to inter-cell interference (ICI). Therefore, the BER performance of the system is reduced and the transmitter must perform unnecessary re-transmission. The proposed scheme uses the CoMP scheme to improve reliability in a heterogeneous network (HetNet) system. Additionally, the proposed scheme uses the constructive spatial phase coding (SPC) scheme to mitigate the received SNR reduction due to the interference signal. Therefore, the proposed scheme can prevent performance degradation caused by the interference signal. When a mobile is located in the cell edge, the transmission signal is distorted by the transmitted signal from the adjacent cell. The proposed scheme can reduce the SNR of the interference signal by using the destructive SPC scheme. Therefore, this scheme can improve the reliability of the system. The simulation results show that the BER performance of the proposed scheme is better than that of the conventional scheme. As a result, the proposed scheme improves the reliability of systems by adaptively applying the CoMP and SPC schemes. Full article

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21 pages, 18311 KiB

Open AccessArticle

Reconstruct Recurrent Neural Networks via Flexible Sub-Models for Time Series Classification

by Ye Ma^*

, Qing Chang, Huanzhang Lu and Junliang Liu

Laboratory of Automatic Target Recognition, College of Electronic Science, National University of Defense Technology (NUDT), Changsha 410073, China

Appl. Sci. 2018, 8(4), 630; https://doi.org/10.3390/app8040630 - 18 Apr 2018

Cited by 6 | Viewed by 4572

Abstract

Recurrent neural networks (RNNs) remain challenging, and there is still a lack of long-term memory or learning ability in sequential data classification and prediction. In this paper, we propose a flexible recurrent model, BIdirectional COnvolutional RaNdom RNNs (BICORN-RNNs), incorporating a series of sub-models: [...] Read more.

Recurrent neural networks (RNNs) remain challenging, and there is still a lack of long-term memory or learning ability in sequential data classification and prediction. In this paper, we propose a flexible recurrent model, BIdirectional COnvolutional RaNdom RNNs (BICORN-RNNs), incorporating a series of sub-models: random projection, convolutional operation, and bidirectional transmission. These subcategories advance classification accuracy, which was limited by the gradient vanishing and the exploding problem. Experiments on public time series datasets demonstrate that our proposed method substantially outperforms a variety of existing models. Furthermore, the coordination of the accuracy and efficiency concerning a variety of factors, including SNR, length, data missing, and overlapping, is also discussed. Full article

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8 pages, 9949 KiB

Open AccessArticle

Blue and Orange Two-Color CW Laser Based on Single-Pass Second-Harmonic and Sum-Frequency Generation in MgO:PPLN

by Dismas K. Choge^1,2

, Huai-Xi Chen¹, Yi-Bin Xu¹, Lei Guo¹, Guang-Wei Li¹ and Wan-Guo Liang^1,*

¹ Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China

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

Appl. Sci. 2018, 8(4), 629; https://doi.org/10.3390/app8040629 - 18 Apr 2018

Cited by 8 | Viewed by 4889

Abstract

We demonstrate a compact blue and orange-two color continuous wave laser source emitting at 487 nm and from 597.4 to 600.3 nm, respectively. The temperature tunable coherent orange radiation is achieved by frequency mixing 974 nm laser diode (LD) and a C-band amplified [...] Read more.

We demonstrate a compact blue and orange-two color continuous wave laser source emitting at 487 nm and from 597.4 to 600.3 nm, respectively. The temperature tunable coherent orange radiation is achieved by frequency mixing 974 nm laser diode (LD) and a C-band amplified spontaneous emission laser source while the temperature insensitive blue radiation is generated by second-order quasi-phase-matching frequency doubling of 974 nm LD. We implement the simultaneous nonlinear processes in a single magnesium oxide doped periodically poled lithium niobate bulk crystal without the need of an aperiodic design. Full article

(This article belongs to the Section Optics and Lasers)

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13 pages, 2072 KiB

Open AccessArticle

Multi-Attributes, Utility-Based, Channel Quality Ranking Mechanism for Cognitive Radio Networks

by Youness Arjoune^*, Zakaria El Mrabet and Naima Kaabouch

Electrical Engineering Department, University of North Dakota; Grand Forks, ND 58202, USA; zakaria.elmrabet @und.edu (Z.E.M.); naima.kaabouch@engr.und.edu (N.K.)

Appl. Sci. 2018, 8(4), 628; https://doi.org/10.3390/app8040628 - 17 Apr 2018

Cited by 15 | Viewed by 4115

Abstract

Cognitive radio is an intelligent wireless solution that aims to enhance the access to the radio spectrum. In this technology, secondary users sense the radio spectrum, select the best channel among a pool of free channels, and determine the optimal transmission parameters to [...] Read more.

Cognitive radio is an intelligent wireless solution that aims to enhance the access to the radio spectrum. In this technology, secondary users sense the radio spectrum, select the best channel among a pool of free channels, and determine the optimal transmission parameters to meet their quality-of-service requirements while maximizing the spectral efficiency. Over the past decade, several channel-ranking mechanisms have been proposed. However, these mechanisms consider only the remaining idle time of the channel and exclude some crucial parameters. This convincingly demonstrates a strong need for a new channel quality-ranking model that jointly considers several parameters to select the best communication channel for transmission. This paper proposes a utility model that integrates several important parameters for ranking channels. First, we underline the importance of the process of the channel quality ranking. Then, we describe a multi-attributes, utility-based, channel quality-ranking model. Finally, we describe a series of experiments and their results, which show that our model effectively ranks the best communication channels first. Full article

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27 pages, 15039 KiB

Open AccessArticle

Solar Radiation Parameters for Assessing Temperature Distributions on Bridge Cross-Sections

by Junqing Xue^1,*

, Jianhui Lin¹, Bruno Briseghella¹

, Habib Tabatabai²

and Baochun Chen¹

¹ College of Civil Engineering, Fuzhou University, Fuzhou, Fujian 350108, China

² Department of Civil and Environmental Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA

Appl. Sci. 2018, 8(4), 627; https://doi.org/10.3390/app8040627 - 17 Apr 2018

Cited by 35 | Viewed by 5091

Abstract

Solar radiation is one of the most important factors influencing the temperature distribution on bridge girder cross-sections. The bridge temperature distribution can be estimated using estimation models that incorporate solar radiation data; however, such data could be cost- or time-prohibitive to obtain. A [...] Read more.

Solar radiation is one of the most important factors influencing the temperature distribution on bridge girder cross-sections. The bridge temperature distribution can be estimated using estimation models that incorporate solar radiation data; however, such data could be cost- or time-prohibitive to obtain. A review of literature was carried out on estimation models for solar radiation parameters, including the global solar radiation, beam solar radiation and diffuse solar radiation. Solar radiation data from eight cities in Fujian Province in southeastern China were obtained on site. Solar radiation models applicable to Fujian, China were proposed and verified using the measured data. The linear Ångström–Page model (based on sunshine duration) can be used to estimate the daily global solar radiation. The Collares-Pereira and Rabl model and the Hottel model can be used to estimate the hourly global solar radiation and the beam solar radiation, respectively. Three bridges were chosen as case study, for which the temperature distribution on girder cross-sections were monitored on site. Finite element models (FEM) of cross-sections of bridge girders were implemented using the Midas program. The temperature–time curves obtained from FEM showed very close agreement with the measured values for summertime. Ignoring the solar radiation effect would result in lower and delayed temperature peaks. However, the influence of solar radiation on the temperature distribution in winter is negligible. Full article

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

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10 pages, 272 KiB

Open AccessArticle

Ultrasound-Based Liver Stiffness Surveillance in Patients Treated for Chronic Hepatitis B or C

by Sheng-Hung Chen^1,2,3

and Cheng-Yuan Peng^2,3,*

¹ Graduate Institute of Clinical Medical Science, School of Medicine, China Medical University, Taichung 40447, Taiwan

² School of Medicine, China Medical University, Taichung 40402, Taiwan

³ Division of Hepatogastroenterology, Department of Internal Medicine, China Medical University Hospital, Taichung 40447, Taiwan

Appl. Sci. 2018, 8(4), 626; https://doi.org/10.3390/app8040626 - 17 Apr 2018

Cited by 3 | Viewed by 5157

Abstract

Evolving modes of ultrasound-based elastography have achieved promising validity and reliability for evaluating liver fibrosis. Liver stiffness (LS) is a valuable biomarker for modeling liver disease progression and regression on a continuous noncategorical scale as changes in LS per year or for determining [...] Read more.

Evolving modes of ultrasound-based elastography have achieved promising validity and reliability for evaluating liver fibrosis. Liver stiffness (LS) is a valuable biomarker for modeling liver disease progression and regression on a continuous noncategorical scale as changes in LS per year or for determining the LS progression or regression rate for refining LS measurement (LSM)-based prognostics. The paradigm of LSMs has altered the focus from liver fibrosis staging alone to comprehensive liver-relevant risk estimations. However, diverse ranges of cohort characteristics, disease types, surveillance protocols and timeframes, necroinflammatory resolutions or biochemical responses (BRs), factors explaining the magnitude or kinetics in LS change, virologic responses (VRs), fibrosis reversals (FRs), and noninvasive surveillance results have rarely been reviewed collectively. Elastography-based LS surveillance alone conveys chronological and valuable patient information and assists in characterizing worldwide patient cohorts under antiviral treatment by delineating the concurrent time elapsed, VR, BR, and FR. In groups with uniform VRs to direct-acting antivirals for chronic hepatitis C and nucleoside and nucleotide analogs for chronic hepatitis B, decline in LS can be explained using concurrent BR from 24 weeks to 3 years, followed by FR and the time elapsed. Full article

(This article belongs to the Special Issue Ultrasound Elastography)

15 pages, 19577 KiB

Open AccessArticle

Diagnostics of Hydrogen-Containing Mixture Compression by a Two-Stage Piston Compressor with Cooling Demand Prediction

by Tomáš Brestovič¹, Mária Čarnogurská^1,*, Miroslav Příhoda², Peter Lukáč¹, Marián Lázár¹, Natália Jasminská¹ and Romana Dobáková¹

¹ Department of Power Engineering, Faculty of Mechanical Engineering, Technical University of Košice, Vysokoškolská 4, 042 00 Košice, Slovakia

² Department of Thermal Engineering, Faculty of Metallurgy and Materials Engineering, VŠB—Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava, Poruba, Czech Republic

Appl. Sci. 2018, 8(4), 625; https://doi.org/10.3390/app8040625 - 17 Apr 2018

Cited by 7 | Viewed by 4953

Abstract

The present article describes the diagnostics of a compressor that is compressing a mixture of H₂ and N₂ on the basis of the results that were obtained by operational measurements of the flow rates and temperatures at selected compressor sites, as [...] Read more.

The present article describes the diagnostics of a compressor that is compressing a mixture of H₂ and N₂ on the basis of the results that were obtained by operational measurements of the flow rates and temperatures at selected compressor sites, as well as of the acoustic pressure levels during the full loading thereof. The obtained data were subsequently used to determine the limit conditions of the compressor operations in terms of the cooling capacity. A thermodynamic analysis of the compression of the H₂/N₂ gas mixture was carried out with subsequent heat and energy flow calculation and the determination of the minimum cooling water flow rate that is required to ensure the continuous compressor operations. Full article

(This article belongs to the Special Issue Green Energy and Applications)

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