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  Subjects -> ENGINEERING (Total: 2287 journals)
    - CHEMICAL ENGINEERING (192 journals)
    - CIVIL ENGINEERING (186 journals)
    - ELECTRICAL ENGINEERING (105 journals)
    - ENGINEERING (1206 journals)
    - ENGINEERING MECHANICS AND MATERIALS (385 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (68 journals)
    - MECHANICAL ENGINEERING (90 journals)

ENGINEERING (1206 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Hybrid Journal   (Followers: 6)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 234)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 6)
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 7)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 10)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 21)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 37)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 1)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 4)
AIChE Journal     Hybrid Journal   (Followers: 30)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 15)
Applied Clay Science     Hybrid Journal   (Followers: 5)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Network Science     Open Access  
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 3)
Applied Sciences     Open Access   (Followers: 2)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 7)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 3)
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 8)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 5)
Batteries     Open Access   (Followers: 4)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 10)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 9)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 14)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 41)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Thermal Engineering     Open Access   (Followers: 3)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 8)
CEAS Space Journal     Hybrid Journal  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 21)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 5)
Coatings     Open Access   (Followers: 3)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 26)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 258)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 180)
Composites Part B : Engineering     Hybrid Journal   (Followers: 236)
Composites Science and Technology     Hybrid Journal   (Followers: 216)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 14)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 17)
Computers & Geosciences     Hybrid Journal   (Followers: 28)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 10)
Computing and Visualization in Science     Hybrid Journal   (Followers: 5)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 30)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 6)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 9)
Control Engineering Practice     Hybrid Journal   (Followers: 42)
Control Theory and Informatics     Open Access   (Followers: 8)
Corrosion Science     Hybrid Journal   (Followers: 25)
CT&F Ciencia, Tecnologia y Futuro     Open Access  
CTheory     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 4)
Current Science     Open Access   (Followers: 58)

        1 2 3 4 5 6 7 | Last

Journal Cover Applied Sciences
  [SJR: 0.178]   [H-I: 9]   [2 followers]  Follow
    
  This is an Open Access Journal Open Access journal
   ISSN (Online) 2076-3417
   Published by MDPI Homepage  [156 journals]
  • Applied Sciences, Vol. 7, Pages 881: Using Canola Oil Biodiesel as an
           Alternative Fuel in Diesel Engines: A Review

    • Authors: Jun Ge, Sam Yoon, Nag Choi
      First page: 881
      Abstract: Due to the rapid development of the global economy, fossil oil is widely used, leading to its depletion and gradual deterioration of the global environment, including global warming, the greenhouse effect, fog, and haze. Therefore, many researchers have been interested in studying alternative fuels in an attempt to develop an eco-friendly fuel to replace traditional fuel and solve the above environmental problems. Biodiesel is a renewable and eco-friendly fuel that is the most promising alternative fuel for diesel engines, and a significant amount of research and development has focused on biodiesel. Canola oil biodiesel (COB) is one type of biodiesel, and it has an advantage in oil production per unit area compared with other biodiesels. This paper summarizes and reviews studies related to the use of COB in different diesel engines under a variety of operating conditions. We focus on evaluating the combustion and emission characteristics of COB based on a large number of papers (including our previous studies). In addition, this paper serves as a valuable reference for in-depth studies of COB use in diesel engines, as it covers the topic from the production of COB to its use in diesel engines.
      Citation: Applied Sciences
      PubDate: 2017-08-28
      DOI: 10.3390/app7090881
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 882: Design of 1-Bit Digital
           Reconfigurable Reflective Metasurface for Beam-Scanning

    • Authors: Shuncheng Tian, Haixia Liu, Long Li
      First page: 882
      Abstract: A 1-bit digital reconfigurable reflective metasurface (RRM) with 20 × 20 cells is presented, fabricated and measured for beam-scanning performance in this paper. The cell is designed with a single layer structure and one varactor diode, controlled electronically. The cell’s phase compensation is over 180° between 3 GHz and 4 GHz and the two states with 180° phase difference are selected as coding “0” and coding “1”. By the fuzzy quantification theory, all the elements on the RRM are set to be coding “0” or coding “1” according to the phase compensation calculated by MATLAB. Furthermore, by changing the coding of the RRM, it can achieve beam-scanning. The simulation results show that the beam-scanning range is over ±60°. The RRM prototype is fabricated and experimentally tested for principle. The gain of the RRM is 18 dB and the 3 dB bandwidth is about 16.6%. The 1-bit digital RRM is preferred in practical implementations due to less error and much easier bias voltage control. The proposed RRM successfully balances the performance and system complexity, especially in the large-scale antenna designs. The experimental and simulated results are in good agreement to prove the correctness and feasibility of the design of the 1-bit digital RRM.
      Citation: Applied Sciences
      PubDate: 2017-08-28
      DOI: 10.3390/app7090882
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 883: An Overview of Additive Manufacturing
           of Titanium Components by Directed Energy Deposition: Microstructure and
           Mechanical Properties

    • Authors: Abdollah Saboori, Donato Gallo, Sara Biamino, Paolo Fino, Mariangela Lombardi
      First page: 883
      Abstract: The directed energy deposition (DED) process can be employed to build net shape components or prototypes starting from powder or wires, through a layer-by-layer process. This process provides an opportunity to fabricate complex shaped and functionally graded parts that can be utilized in different engineering applications. DED uses a laser as a focused heat source to melt the in-situ delivered powder or wire-shaped raw materials. In the past years extensive studies on DED have shown that this process has great potential in order to be used for (i) rapid prototyping of metallic parts, (ii) fabrication of complex and customized parts, (iii) repairing/cladding valuable components which cannot be repaired by other traditional techniques. However, the industrial adoption of this process is still challenging owing to the lack of knowledge on the mechanical performances of the constructed components and also on the trustworthiness/durability of engineering parts produced by DED. This manuscript provides an overview of the additive manufacturing (AM) of titanium alloys and focuses in particular on the mechanical properties and microstructure of components fabricated by DED.
      Citation: Applied Sciences
      PubDate: 2017-08-28
      DOI: 10.3390/app7090883
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 885: Reduction of Bias and Light
           Instability of Mixed Oxide Thin-Film Transistors

    • Authors: Mallory Mativenga, Jae Um, Jin Jang
      First page: 885
      Abstract: Despite their potential use as pixel-switching elements in displays, the bias and light instability of mixed oxide semiconductor thin-film transistors (TFTs) still limit their application to commercial products. Lack of reproducible results due to the sensitivity of the mixed oxides to air exposure and chemical contamination during or after fabrication hinders any progress towards the achievement of stable performance. Consequently, one finds in literature several theories and mechanisms, all justified, but most of them conflict despite being on the same subject matter. In this study, we show that under an optimized fabrication process, which involves the in situ passivation of a mixed oxide semiconductor, we can reduce the bias and light instability of the mixed-oxide semiconductor TFTs by decreasing the semiconductor thickness. We achieve a negligible threshold voltage shift under negative bias combined with light illumination stress when the mixed oxide semiconductor thickness is around three nanometers. The improvement of stability in the thin mixed-oxide semiconductor TFTs is due to a reduced number of oxygen-vacancy defects in the bulk of the semiconductor, as their total number decreases with decreasing thickness. Under the optimized fabrication process, bulk, rather than interfacial defects, thus seem to be the main source of the bias and light instability in mixed oxide TFTs.
      Citation: Applied Sciences
      PubDate: 2017-08-29
      DOI: 10.3390/app7090885
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 886: Road Safety Risk Evaluation Using
           

    • Authors: Syyed Shah, Tom Brijs, Naveed Ahmad, Ali Pirdavani, Yongjun Shen, Muhammad Basheer
      First page: 886
      Abstract: Identification of the most significant factors for evaluating road risk level is an important question in road safety research, predominantly for decision-making processes. However, model selection for this specific purpose is the most relevant focus in current research. In this paper, we proposed a new methodological approach for road safety risk evaluation, which is a two-stage framework consisting of data envelopment analysis (DEA) in combination with artificial neural networks (ANNs). In the first phase, the risk level of the road segments under study was calculated by applying DEA, and high-risk segments were identified. Then, the ANNs technique was adopted in the second phase, which appears to be a valuable analytical tool for risk prediction. The practical application of DEA-ANN approach within the Geographical Information System (GIS) environment will be an efficient approach for road safety risk analysis.
      Citation: Applied Sciences
      PubDate: 2017-08-29
      DOI: 10.3390/app7090886
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 887: Stochastic and Higher-Order Effects
           on Exploding Pulses

    • Authors: Orazio Descalzi, Carlos Cartes
      First page: 887
      Abstract: The influence of additive noise, multiplicative noise, and higher-order effects on exploding solitons in the framework of the prototype complex cubic-quintic Ginzburg-Landau equation is studied. Transitions from explosions to filling-in to the noisy spatially homogeneous finite amplitude solution, collapse (zero solution), and periodic exploding dissipative solitons are reported.
      Citation: Applied Sciences
      PubDate: 2017-08-30
      DOI: 10.3390/app7090887
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 888: Impacts of Sample Design for
           Validation Data on the Accuracy of Feedforward Neural Network
           Classification

    • Authors: Giles Foody
      First page: 888
      Abstract: Validation data are often used to evaluate the performance of a trained neural network and used in the selection of a network deemed optimal for the task at-hand. Optimality is commonly assessed with a measure, such as overall classification accuracy. The latter is often calculated directly from a confusion matrix showing the counts of cases in the validation set with particular labelling properties. The sample design used to form the validation set can, however, influence the estimated magnitude of the accuracy. Commonly, the validation set is formed with a stratified sample to give balanced classes, but also via random sampling, which reflects class abundance. It is suggested that if the ultimate aim is to accurately classify a dataset in which the classes do vary in abundance, a validation set formed via random, rather than stratified, sampling is preferred. This is illustrated with the classification of simulated and remotely-sensed datasets. With both datasets, statistically significant differences in the accuracy with which the data could be classified arose from the use of validation sets formed via random and stratified sampling (z = 2.7 and 1.9 for the simulated and real datasets respectively, for both p < 0.05%). The accuracy of the classifications that used a stratified sample in validation were smaller, a result of cases of an abundant class being commissioned into a rarer class. Simple means to address the issue are suggested.
      Citation: Applied Sciences
      PubDate: 2017-08-30
      DOI: 10.3390/app7090888
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 889: An Investigation of Oxide Coating
           Synthesized on an Aluminum Alloy by Plasma Electrolytic Oxidation in
           Molten Salt

    • Authors: Alexander Sobolev, Alexey Kossenko, Michael Zinigrad, Konstantin Borodianskiy
      First page: 889
      Abstract: Plasma electrolytic oxidation (PEO) is a surface treatment process for obtaining oxide coatings with a high performance on valve metals. PEO is mostly performed in an aqueous solution electrolyte that limits the size of treated parts due to the fact that the system is heated. Therefore, the coating of large surfaces cannot be synthesized in an aqueous electrolyte. In the current work, an alternative approach of PEO treatment, whereby an aluminum 1050 alloy in nitrate molten salt at a temperature of 280 °C is applied, was investigated. The microstructure, phase and chemical compositions, and micro-hardness were examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and micro-hardness tests. The obtained results show that formed coating contains from two sub-layers: one is the outer sub-layer of the α-Al2O3 phase and the second is its inner sub-layer. It was found that the formed coating was free of any contaminants originating from the electrolyte and had no cracks or pores, which are usually present in coatings formed by PEO treatment in an aqueous solution electrolyte.
      Citation: Applied Sciences
      PubDate: 2017-08-30
      DOI: 10.3390/app7090889
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 890: Characterization of Piezoelectric
           Microgenerator with Nanobranched ZnO Grown on a Polymer Coated Flexible
           Substrate

    • Authors: Mariya Aleksandrova, Georgi Kolev, Yordanka Vucheva, Habib Pathan, Krassimir Denishev
      First page: 890
      Abstract: In this paper, results from the fabrication and study of a piezoelectric microgenerator using nanobranched zinc oxide (ZnO) film grown on poly(3,4-ethylenedioxythiphene) doped with a sulfonate (PEDOT:PSS)-coated flexible substrate are presented. The aim of the study is to extract information about the electrical behavior of the harvester at different frequencies, temperatures, and positions, as related to the ZnO nanostructure, as well as to examine its piezoelectric response. Radiofrequency (RF) sputtering with oxygen deficit during growth on an amorphous sublayer was used to obtain the nanobranched structure. The microdevice was studied at frequencies ranging from 1 Hz to 1 MHz for temperatures in the range of −10 °C to 40 °C, in both a non-bended position, and a radius of curvature position bended to 12 mm. It was found that non-ordered ZnO nanoformations facilitate the dipoles’ motion, thus leading to low dielectric losses of 10−3, and a higher relative permittivity of εr ~15, compared with typically known values. The losses increase with one order of magnitude at bending, but still remain low. Dielectric characteristics indicate that the favorable working range of the microgenerator is within the lower frequency region, from 10 Hz to 10 kHz. The results were confirmed by the measured open circuit voltage, which reaches approximately 1 V within this range, versus 300 mV out of the range.
      Citation: Applied Sciences
      PubDate: 2017-09-01
      DOI: 10.3390/app7090890
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 891: Precision Irrigation System (PIS)
           Using Sensor Network Technology Integrated with IOS/Android Application

    • Authors: Mehmet Işık, Yusuf Sönmez, Cemal Yılmaz, Veysel Özdemir, Ercan Yılmaz
      First page: 891
      Abstract: One of the most important factors for successful agricultural production is the irrigation system in place. In this study, a precision irrigation system, which takes advantage of the various phases of plant growth, was developed and implemented using the sensor network technology integrated with IOS/Android. The amount of water in the soil was measured via sensors that were placed on certain points of the area to be irrigated. These sensors were placed near the root of the product. Data from sensors was transmitted via Wi-Fi in real-time to a mobile phone based on IOS/Android. In the light of obtained data, the seasonal precision irrigation system was created depending on the amount of water required by the plants at each stage of their growth stage. The required energy of the system was provided by solar energy. The system can be controlled by smart phones, which increases the usability of the system. When design performance was analyzed, it was observed that some important advantages such as obtaining high efficiency with water, time and energy saving and reducing the workforce were ensured. Five separate laterals were used for the irrigation system. There were valves on each lateral, which realized the opening and closing process depending on the water need. A total of 16 humidity sensors were used in the irrigation system and the data from these sensors was transferred to the IOS/Android server via the programmable controller (PLC). The basic electrical equipment in the irrigation system was monitored and controlled via mobile devices. Control parameters were obtained by comparing the real values and reference values by a closed-loop system and determine the new working status of the irrigation system.
      Citation: Applied Sciences
      PubDate: 2017-09-01
      DOI: 10.3390/app7090891
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 892: Temporally Programmable Hybrid MOPA
           Laser with Arbitrary Pulse Shape and Frequency Doubling

    • Authors: Mingming Nie, Qiang Liu, Encai Ji, Xuezhe Cao, Xing Fu
      First page: 892
      Abstract: An arbitrary pulse shape by compensating gain saturation in a solid-state Master oscillator power amplifier (MOPA) system made up of three Neodymium doped yttrium vanadate (Nd:YVO4) amplifiers is demonstrated. By investigating the amplifier dynamics in detail, car-shaped pulse shapes were obtained with compensated pulse distortion. Desired pulse shapes, such as multiple-step, square, parabolic, and Gaussian pulses, were achieved, with a high peak power level of 41.6 kW and a narrow linewidth less than 0.06 nm. In addition, through second harmonic generation (SHG), a green laser with different pulse shapes was obtained, with a maximum conversion efficiency of 42.6%.
      Citation: Applied Sciences
      PubDate: 2017-09-01
      DOI: 10.3390/app7090892
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 893: Multi-Scale Evaluation of the
           Interphase Zone between the Overlay and Concrete Substrate: Methods and
           Descriptors

    • Authors: Łukasz Sadowski
      First page: 893
      Abstract: This article presents the problem of examining the interphase zone between the overlay and concrete substrate at different levels of observation. The possibility of applying available modern research methods in order to examine the interphase zone with regard to the level of observation is presented. These levels were defined in the paper. Examples of tests that show a possible approach to the examination of the interphase zone are also presented.
      Citation: Applied Sciences
      PubDate: 2017-09-01
      DOI: 10.3390/app7090893
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 894: Perspective on Double Pulsed Gas
           Metal Arc Welding

    • Authors: Leilei Wang, Jiaxiang Xue
      First page: 894
      Abstract: Aluminum alloy welding suffers from problems such as solidification cracking and hydrogen-induced porosity, which are sufficiently severe to limit its potential applications. Because mitigated porosity incidence and solidification cracking are observed in aluminum welds using double pulsed gas metal arc welding (DP-GMAW), a comprehensive review of the mechanism is necessary, but absent from the literature. The oscillation of arc force and droplet pressure causes a weld pool stir effect. The expansion and shrinkage of the weld pool cause unusual remelting and resolidification of the previously solidified metal. DP-GMAW has an increased solidification growth rate and cooling rate, compared with conventional pulsed welding at same heat input. Both numerical and experimental results reveal the remarkable concept that refined microstructure in the fusion zone is obtained by using DP-GMAW. The mechanism of microstructural refinement is revealed as a weld pool stir effect and increased cooling rate. Hydrogen bubbles easily float out and then release from the weld pool originated from the weld pool stir effect. Reduced solidification cracking is achieved due to the refined solidification structure that originated from the increased cooling rate. The advantages, evolution process, and future trend of DP-GMAW are discussed.
      Citation: Applied Sciences
      PubDate: 2017-09-01
      DOI: 10.3390/app7090894
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 895: Experimental Study on Robustness of
           an Eddy Current-Tuned Mass Damper

    • Authors: Junda Chen, Guangtao Lu, Yourong Li, Tao Wang, Wenxi Wang, Gangbing Song
      First page: 895
      Abstract: In this paper, an eddy current tuned mass damper (ECTMD) is utilized to control the vibration of a cantilever beam. The robustness of the ECTMD against frequency detuning is experimentally studied in cases of both free vibration and forced vibration. The natural frequency of the cantilever beam can be adjusted by changing the location of a lumped mass. For purposes of comparison with the ECTMD, the robustness of a tuned mass damper (TMD) is also studied. The experimental results in the free vibration case indicate that the ECTMD works well both in tuned and detuned situations, and the equivalent damping ratio of the cantilever beam equipped with the ECTMD is 2.08~5.91 times that of the TMD. However, the TMD only suppresses the free vibration effectively in the tuned situation. With forced vibration, the experimental results also demonstrate the robustness of the ECTMD in vibration suppression in detuned cases. On the other hand, the cantilever beam with TMD experiences 1.63~2.99 times the peak vibration of that of the ECTMD control.
      Citation: Applied Sciences
      PubDate: 2017-09-01
      DOI: 10.3390/app7090895
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 896: A Review of Distributed Fibre Optic
           Sensors for Geo-Hydrological Applications

    • Authors: Luca Schenato
      First page: 896
      Abstract: Distributed optical fibre sensing, employing either Rayleigh, Raman, or Brillouin scattering, is the only physical-contact sensor technology capable of accurately estimating physical fields with spatial continuity along the fibre. This unique feature and the other features of standard optical fibre sensors (e.g., minimal invasiveness and lightweight, remote powering/interrogating capabilities) have for many years promoted the technology to be a promising candidate for geo-hydrological monitoring. Relentless research efforts are being undertaken to bring the technology to complete maturity through laboratory, physical models, and in-situ tests. The application of distributed optical fibre sensors to geo-hydrological monitoring is here reviewed and discussed, along with basic principles and main acquisition techniques. Among the many existing geo-hydrological processes, the emphasis is placed on those related to soil levees, slopes/landslide, and ground subsidence that constitute a significant percentage of current geohazards.
      Citation: Applied Sciences
      PubDate: 2017-09-01
      DOI: 10.3390/app7090896
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 897: Properties of Aged GFRP Reinforcement
           Grids Related to Fatigue Life and Alkaline Environment

    • Authors: Francesco Micelli, Marco Corradi, Maria Aiello, Antonio Borri
      First page: 897
      Abstract: In recent years, even if Fiber Reinforced Polymer (FRP) composites have been widely used for strengthening of civil buildings, a new generation of materials has been studied and proposed for historical masonry construction. These buildings, mainly made of stone work, are common in many areas of Europe and Asia and recent earthquakes has been the cause of many catastrophic failures. The brittleness of unreinforced historic masonry can be considerably reduced using new retrofitting lighter-weight materials such FRP, even if limitations were evidenced due to material and mechanical compatibility with poor substrates. Thus, fibrous reinforcements were used as long fibres incorporated into a cement or lime matrix, which better match with the properties of ancient masonry. The use of low strength fibers such as glass and basalt, respect to carbon, in presence of an alkaline matrix brought out durability issues, due to the chemical vulnerability of common glass and basalt fibres. The objective of this research is to explore the effects of selected aqueous environments and fatigue loading on the mechanical and physical properties of composite grids, made of E-CR (Electrical/Chemical Resistance) glass fibers and epoxy-vinylester resin, used as tensile reinforcement in new composite reinforced mortar systems. Glass-fiber-reinforced polymer (GFRP) coupons were subjected to tensile testing and a severe protocol of durability tests, including alkaline environment and fatigue tensile loads. Accelerated ageing tests were used to simulate long-term degradation in terms of chemical attack and consequent reduction of tensile strength. The ageing protocol consisted of immersion at 40 °C in alkaline bath made by deionized water and Ca(OH)2, 0.16% in weight, solution for 30 days. GFRP specimens aged and unaged were also tested under tensile fatigue cycles up to 1,000,000 cycles and a nominal frequency of 7.5 Hz. After this severe conditioning the tests indicate a good tensile strength retention of the GFRP in absence of fatigue loads, while a significant loss in fatigue life was experienced when both alkaline exposure and fatigue loads were applied.
      Citation: Applied Sciences
      PubDate: 2017-09-01
      DOI: 10.3390/app7090897
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 898: Comparative Study of Two
           Dynamics-Model-Based Estimation Algorithms for Distributed Drive Electric
           Vehicles

    • Authors: Xudong Zhang, Dietmar Göhlich, Chenrui Fu
      First page: 898
      Abstract: The effect of vehicle active safety systems is subject to the accurate knowledge of vehicle states. Therefore, it is of great importance to develop a precise and robust estimation approach so as to deal with nonlinear vehicle dynamics systems. In this paper, a planar vehicle model with a simplified tire model is established first. Two advanced model-based estimation algorithms, an unscented Kalman filter and a moving horizon estimation, are developed for distributed drive electric vehicles. Using the proposed algorithms, vehicle longitudinal velocity, lateral velocity, yaw rate as well as lateral tire forces are estimated based on information fusion of standard sensors in today’s typical vehicle and feedback signals from electric motors. Computer simulations are implemented in the environment of CarSim combined with Matlab/Simulink. The performance of both estimators regarding convergence, accuracy, and robustness against an incorrect initial estimate of longitudinal velocity is compared in detail. The comparison results demonstrate that both estimation approaches have favourable coincidence with the corresponding reference values, while the moving horizon estimation is more accurate and robust, and owns faster convergence.
      Citation: Applied Sciences
      PubDate: 2017-09-01
      DOI: 10.3390/app7090898
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 899: A Dispersive Inelastic X-ray
           Scattering Spectrometer for Use at X-ray Free Electron Lasers

    • Authors: Jakub Szlachetko, Maarten Nachtegaal, Daniel Grolimund, Gregor Knopp, Sergey Peredkov, Joanna Czapla–Masztafiak, Christopher Milne
      First page: 899
      Abstract: We report on the application of a short working distance von Hamos geometry spectrometer to measure the inelastic X-ray scattering (IXS) signals from solids and liquids. In contrast to typical IXS instruments where the spectrometer geometry is fixed and the incoming beam energy is scanned, the von Hamos geometry allows measurements to be made using a fixed optical arrangement with no moving parts. Thanks to the shot-to-shot capability of the spectrometer setup, we anticipate its application for the IXS technique at X-ray free electron lasers (XFELs). We discuss the capability of the spectrometer setup for IXS studies in terms of efficiency and required total incident photon flux for a given signal-to-noise ratio. The ultimate energy resolution of the spectrometer, which is a key parameter for IXS studies, was measured to the level of 150 meV at short crystal radius thanks to the application of segmented crystals for X-ray diffraction. The short working distance is a key parameter for spectrometer efficiency that is necessary to measure weak IXS signals.
      Citation: Applied Sciences
      PubDate: 2017-09-01
      DOI: 10.3390/app7090899
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 900: Distinguishing Different Cancerous
           Human Cells by Raman Spectroscopy Based on Discriminant Analysis Methods

    • Authors: Mingjie Tang, Liangping Xia, Dongshan Wei, Shihan Yan, Chunlei Du, Hong-Liang Cui
      First page: 900
      Abstract: An approach to distinguish eight kinds of different human cells by Raman spectroscopy was proposed and demonstrated in this paper. Original spectra of suspension cells in the frequency range of 623~1783 cm−1 were acquired and pre-processed by baseline calibration, and principal component analysis (PCA) was employed to extract the useful spectral information. To develop a robust discrimination model, a linear discriminant analysis (LDA) and quadratic discriminant analysis (QDA) were attempted comparatively in the work. The results showed that the QDA model is better than the LDA model. The optimal QDA model was generated with 12 principal components. The classification rates are 100% in the calibration and prediction set, respectively. From the experimental results, it is concluded that Raman spectroscopy combined with appropriate discriminant analysis methods has significant potential in human cell detection.
      Citation: Applied Sciences
      PubDate: 2017-09-01
      DOI: 10.3390/app7090900
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 901: A Two-Stage Approach to Note-Level
           Transcription of a Specific Piano

    • Authors: Qi Wang, Ruohua Zhou, Yonghong Yan
      First page: 901
      Abstract: This paper presents a two-stage transcription framework for a specific piano, which combines deep learning and spectrogram factorization techniques. In the first stage, two convolutional neural networks (CNNs) are adopted to recognize the notes of the piano preliminarily, and note verification for the specific individual is conducted in the second stage. The note recognition stage is independent of piano individual, in which one CNN is used to detect onsets and another is used to estimate the probabilities of pitches at each detected onset. Hence, candidate pitches at candidate onsets are obtained in the first stage. During the note verification, templates for the specific piano are generated to model the attack of note per pitch. Then, the spectrogram of the segment around candidate onset is factorized using attack templates of candidate pitches. In this way, not only the pitches are picked up by note activations, but the onsets are revised. Experiments show that CNN outperforms other types of neural networks in both onset detection and pitch estimation, and the combination of two CNNs yields better performance than a single CNN in note recognition. We also observe that note verification further improves the performance of transcription. In the transcription of a specific piano, the proposed system achieves 82% on note-wise F-measure, which outperforms the state-of-the-art.
      Citation: Applied Sciences
      PubDate: 2017-09-02
      DOI: 10.3390/app7090901
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 902: Fabrication and Characterizations of
           Hot-Melt Extruded Nanocomposites Based on Zinc Sulfate Monohydrate and
           Soluplus

    • Authors: Song Lee, Suyeong Nam, Yohan Choi, Minju Kim, Ja Koo, Byung-Jo Chae, Wie-Soo Kang, Hyun-Jong Cho
      First page: 902
      Abstract: Zinc sulfate monohydrate (ZnSO4)-loaded nanocomposites (NCs) were fabricated by using a hot-melt extruder (HME) system. Soluplus (SP) was adopted as an amphiphilic polymer matrix for HME processing. The micro-size of ZnSO4 dispersion was reduced to nano-size by HME processing with the use of SP. ZnSO4 could be homogeneously dispersed in SP through HME processing. ZnSO4/SP NCs with a 75 nm mean diameter, a 0.1 polydispersity index, and a −1 mV zeta potential value were prepared. The physicochemical properties of ZnSO4/SP NCs and the existence of SP in ZnSO4/SP NCs were further investigated by solid-state studies. Nano-size range of ZnSO4/SP NC dispersion was maintained in the simulated gastrointestinal environments (pH 1.2 and 6.8 media). No severe toxicity in intestinal epithelium after oral administration of ZnSO4/SP NCs (at 100 mg/kg dose of ZnSO4, single dosing) was observed in rats. These results imply that developed ZnSO4/SP NC can be used as a promising nano-sized zinc supplement formulation. In addition, developed HME technology can be widely applied to fabricate nanoformulations of inorganic materials.
      Citation: Applied Sciences
      PubDate: 2017-09-04
      DOI: 10.3390/app7090902
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 903: Collision Avoidance from Multiple
           Passive Agents with Partially Predictable Behavior

    • Authors: Khalil Zuhaib, Abdul Khan, Junaid Iqbal, Mian Ali, Muhammad Usman, Ahmad Ali, Sheraz Yaqub, Ji Lee, Changsoo Han
      First page: 903
      Abstract: Navigating a robot in a dynamic environment is a challenging task, especially when the behavior of other agents such as pedestrians, is only partially predictable. Also, the kinodynamic constraints on robot motion add an extra challenge. This paper proposes a novel navigational strategy for collision avoidance of a kinodynamically constrained robot from multiple moving passive agents with partially predictable behavior. Specifically, this paper presents a new approach to identify the set of control inputs to the robot, named control obstacle, which leads it towards a collision with a passive agent moving along an arbitrary path. The proposed method is developed by generalizing the concept of nonlinear velocity obstacle (NLVO), which is used to avoid collision with a passive agent, and takes into account the kinodynamic constraints on robot motion. Further, it formulates the navigational problem as an optimization problem, which allows the robot to make a safe decision in the presence of various sources of unmodelled uncertainties. Finally, the performance of the algorithm is evaluated for different parameters and is compared to existing velocity obstacle-based approaches. The simulated experiments show the excellent performance of the proposed approach in term of computation time and success rate.
      Citation: Applied Sciences
      PubDate: 2017-09-04
      DOI: 10.3390/app7090903
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 904: Effects of Using Different Sources of
           Remote Sensing and Geographic Information System Data on Urban Stormwater
           2D–1D Modeling

    • Authors: Yi Hong, Céline Bonhomme, Bahman Soheilian, Ghassan Chebbo
      First page: 904
      Abstract: Remote sensing (RS) and geographic information system (GIS) data is increasingly used in urban stormwater modeling. The undirected use of such data may waste economic and human resources. In order to provide guidance for practitioners to efficiently use different data collection resources, as well as give a reference for future works, this paper aims to assess the effects of using free access GIS data and ad hoc RS data on urban 2D–1D stormwater modeling. The 2D-surface Two-dimensional Runoff, Erosion, and Export model (TREX) model was published in Science of the Total Environment in 2008. The 1D-sewer CANOE (Logiciel intégré de conception et de diagnostic des réseaux d’assainissement) model was published in Journal of Hydrology in 2004. The two models are integrated in the TRENOE (TREX-CANOE) platform. The modeling approach is applied to a small urban catchment near Paris (Le Perreux sur Marne, 0.12 km2). Simulation results reveal that the detailed land-use information derived from multiple data sources is a crucial factor for accurate simulations. Nevertheless, using the very high resolution LiDAR (light detection and ranging) data is not equally significant for the water flow simulations at sewage outlets. Finally, we suggest that using the free access GIS data accompanying the urban sewer network design might be an acceptable low-cost solution for accurate urban 2D–1D stormwater modeling during moderate rainfall events. Further studies of urban stormwater modeling could focus on the development of “suitable” models with “enough” input data, depending on the management/research objectives.
      Citation: Applied Sciences
      PubDate: 2017-09-05
      DOI: 10.3390/app7090904
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 905: Analysis of MTF in TDI-CCD Subpixel
           Dynamic Super-Resolution Imaging by Beam Splitter

    • Authors: Kun Gao, Lu Han, Hongmiao Liu, Zeyang Dou, Guoqiang Ni, Yingjie Zhou
      First page: 905
      Abstract: The subpixel dynamic imaging technique of a beam splitter is one of the most effective super-resolution imaging methods. Aiming to create a linear time delay integration charge coupled device (TDI–CCD) subpixel imaging system based on the optical assembly method, its modulation transfer function (MTF) is analyzed based on the spatial over-sampling theory. Firstly, Fourier transformation of the sampling point is used to describe the frequency domain characteristics of TDI–CCD, which transform a unit cell of the spatial sampling lattice into a bandwidth cell in the spatial–frequency domain. Considering the effects of velocity mismatch and misalignment, the best subpixel staggering position of the linear TDI–CCD pair is given. Moreover, according to the analysis of the MTF of super-resolution reconstruction results from multiple subpixel images with random spatial offsets, the condition of sampling in the limitation of the enhancement of MTF is obtained. The numerical simulation and real experimental analysis reveal results that are consistent with the theoretical model.
      Citation: Applied Sciences
      PubDate: 2017-09-05
      DOI: 10.3390/app7090905
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 906: LiDARgrammetry: A New Method for
           Generating Synthetic Stereoscopic Products from Digital Elevation Models

    • Authors: Ricardo Rodríguez-Cielos, José Galán-García, Yolanda Padilla-Domínguez, Pedro Rodríguez-Cielos, Ana Bello-Patricio, José López-Medina
      First page: 906
      Abstract: There are currently several new technologies being used to generate digital elevation models that do not use photogrammetric techniques. For example, LiDAR (Laser Imaging Detection and Ranging) and RADAR (RAdio Detection And Ranging) can generate 3D points and reflectivity information of the surface without using a photogrammetric approach. In the case of LiDAR, the intensity level indicates the amount of energy that the object reflects after a laser pulse is transmitted. This energy mainly depends on the material and the wavelength used by LiDAR. This intensity level can be used to generate a synthetic image colored by this attribute (intensity level), which can be viewed as a RGB (red, green and blue) picture. This work presents the outline of an innovative method, designed by the authors, to generate synthetic pictures from point clouds to use in classical photogrammetric software (digital restitution or stereoscopic vision). This is conducted using available additional information (for example, the intensity level of LiDAR). This allows mapping operators to view the LiDAR as if it were stereo-imagery, so they can manually digitize points, 3D lines, break lines, polygons and so on.
      Citation: Applied Sciences
      PubDate: 2017-09-12
      DOI: 10.3390/app7090906
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 907: Inverse Optimal Design for Position
           Control of a Quadrotor

    • Authors: Keun Lee, Yoon Choi, Jin Park
      First page: 907
      Abstract: In this paper, we propose an inverse optimal design method for the position control of a quadrotor. First, we derive the dynamics of a quadrotor using the Newton-Euler formulation. Second, we present the state transformation technique to derive the position dynamics from the kinematic and dynamic models of a quadrotor. Then, we present the nonlinear inverse optimal position control of a quadrotor. The stability analysis based on Lyapunov theorem shows that the proposed control method can realize a quadrotor system that is exponentially stabilized. In addition, we show the inverse optimality of the proposed inverse optimal controller for the position control of a quadrotor. The inverse optimality can simply and clearly be shown using the state transformation technique. Finally, we present some simulation results to verify the effectiveness of the proposed control method.
      Citation: Applied Sciences
      PubDate: 2017-09-05
      DOI: 10.3390/app7090907
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 908: Estimation of the Performance
           Improvement of Pre-Amplified PAM4 Systems When Using Multi-Section
           Semiconductor Optical Amplifiers

    • Authors: Seán Ó Dúill, Pascal Landais, Liam Barry
      First page: 908
      Abstract: Multi-section semiconductor optical amplifiers (SOA) have been shown to have superior noise and linearity performance compared with single section SOAs. We show how to create a simplified numerical model for multi-section SOAs that is suitable for optical communication system simulations and use that model to investigate the amplification performance of 56 Gbit/s four-level pulse amplitude modulation signals. We find that a multi-section SOA could provide an improvement in input power dynamic range exceeding 3 dB compared to a single section SOA that has the same unsaturated gain.
      Citation: Applied Sciences
      PubDate: 2017-09-05
      DOI: 10.3390/app7090908
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 909: Laser Welding under Vacuum: A Review

    • Authors: Meng Jiang, Wang Tao, Yanbin Chen
      First page: 909
      Abstract: Laser welding has been widely used in various industry fields. In order to further alter and broaden its applicability, a novel technology of laser welding under vacuum is introduced. The combination of high power laser and low ambient pressure provides an excellent welding performance and quality. In this paper, an overview on laser welding under vacuum is presented. It begins with a short introduction about the research status of laser welding under vacuum. Next, the equipment of laser welding under vacuum is introduced. Then, the fundamental phenomena of laser welding under vacuum, including penetration depth, weld geometry, plasma plume, molten pool and keyhole behaviors, are summarized in detail. Finally, the applications and prospects of laser welding under vacuum are proposed.
      Citation: Applied Sciences
      PubDate: 2017-09-05
      DOI: 10.3390/app7090909
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 910: Properties of Extrusion Concrete
           Panel Using Waste Concrete Powder

    • Authors: Ha-Seog Kim, Sea-Hyun Lee, Byoungil Kim
      First page: 910
      Abstract: There has been an increasing amount of waste concrete generated in recent years, which has made recycling more important. Waste concrete is generally recycled as recycled aggregates, and many studies have been conducted to seek ways to improve their quality. Such quality improvement processes has led to the generation of byproducts such as waste concrete powder, which needs to be recycled efficiently based on further research. Accordingly, this study was conducted with the aim to use waste concrete powder (WCP) to substitute silica powder in the manufacturing of the extrusion concrete panels in cases where high SiO2 content is not a requirement. The results of this study showed a negative correlation between flexural strength and silica powder-WCP substitution ratio. For example, 50% substitution resulted in a product that satisfied the required flexural strength over 14 MPa as stipulated by the Korean Industrials Standards, and it gave rise to properties such as specific gravity, absorption ratio, length change, thermal conductivity, and fire-resistance that were similar to those of plain specimens. Based on these results, it was deemed that it would be possible to use WCP as an alternative material in place of siliceous fillers in cases where high-purity is not required.
      Citation: Applied Sciences
      PubDate: 2017-09-05
      DOI: 10.3390/app7090910
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 911: The NARX Model-Based System
           Identification on Nonlinear, Rotor-Bearing Systems

    • Authors: Ying Ma, Haopeng Liu, Yunpeng Zhu, Fei Wang, Zhong Luo
      First page: 911
      Abstract: In practice, it is usually difficult to obtain the physical model of nonlinear, rotor-bearing systems due to uncertain nonlinearities. In order to solve this issue to conduct the analysis and design of nonlinear, rotor-bearing systems, in this study, a data driven NARX (Nonlinear Auto-Regressive with exogenous inputs) model is identified. Due to the lack of the random input signal which is required in the identification of a system′s NARX model, for nonlinear, rotor-bearing systems, a new multi-harmonic input based model identification approach is introduced. Moreover, the identification results of NARX models on the nonlinear, rotor-bearing systems are validated under different conditions (such as: low speed, critical speed, and over critical speed), illustrating the applicability of the proposed approach. Finally, an experimental test is conducted to identify the NARX model of the nonlinear rotor test rig, showing that the NARX model can be used to reproduce the characteristics of the underlying system accurately, which provides a reliable model for dynamic analysis, control, and fault diagnosis of the nonlinear, rotor-bearing system.
      Citation: Applied Sciences
      PubDate: 2017-09-05
      DOI: 10.3390/app7090911
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 912: Habitat Potential Mapping of Marten
           (Martes flavigula) and Leopard Cat (Prionailurus bengalensis) in South
           Korea Using Artificial Neural Network Machine Learning

    • Authors: Saro Lee, Sunmin Lee, Wonkyong Song, Moung-Jin Lee
      First page: 912
      Abstract: This study developed habitat potential maps for the marten (Martes flavigula) and leopard cat (Prionailurus bengalensis) in South Korea. Both species are registered on the Red List of the International Union for Conservation of Nature, which means that they need to be managed properly. Various factors influencing the habitat distributions of the marten and leopard were identified to create habitat potential maps, including elevation, slope, timber type and age, land cover, and distances from a forest stand, road, or drainage. A spatial database for each species was constructed by preprocessing Geographic Information System (GIS) data, and the spatial relationship between the distribution of leopard cats and environmental factors was analyzed using an artificial neural network (ANN) model. This process used half of the existing habitat location data for the marten and leopard cat for training. Habitat potential maps were then created considering the relationships. Using the remaining half of the habitat location data for each species, the model was validated. The results of the model were relatively successful, predicting approximately 85% for the marten and approximately 87% for the leopard cat. Therefore, the habitat potential maps can be used for monitoring the habitats of both species and managing these habitats effectively.
      Citation: Applied Sciences
      PubDate: 2017-09-05
      DOI: 10.3390/app7090912
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 913: Comparison of Laser-Engraved Hole
           Properties between Cold-Rolled and Laser Additive Manufactured Stainless
           Steel Sheets

    • Authors: Matti Manninen, Marika Hirvimäki, Ville-Pekka Matilainen, Antti Salminen
      First page: 913
      Abstract: Laser drilling and laser engraving are common manufacturing processes that are found in many applications. With the continuous progress of additive manufacturing (3D printing), these processes can now be applied to the materials used in 3D printing. However, there is a lack of knowledge about how these new materials behave when processed or machined. In this study, sheets of 316L stainless steel produced by both the traditional cold rolling method and by powder bed fusion (PBF) were laser drilled by a nanosecond pulsed fiber laser. Results were then analyzed to find out whether there are measurable differences in laser processing parts that are produced by either PBF (3D printing) or traditional steel parts. Hole diameters, the widths of burn effects, material removal rates, and hole tapers were measured and compared. Additionally, differences in microstructures of the samples were also analyzed and compared. Results show negligible differences in terms of material processing efficiency. The only significant differences were that the PBF sample had a wider burn effect, and had some defects in the microstructure that were more closely analyzed. The defects were found to be shallow recesses in the material. Some of the defects were deep within the material, at the end and start points of the laser lines, and some were close to the surfaces of the sample.
      Citation: Applied Sciences
      PubDate: 2017-09-06
      DOI: 10.3390/app7090913
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 914: Investigation of Laser Cutting Width
           of LiCoO2 Coated Aluminum for Lithium-Ion Batteries

    • Authors: Dongkyoung Lee, Sanghoon Ahn
      First page: 914
      Abstract: Lithium-ion batteries are widely used for many applications such as portable electronic devices and Electric Vehicles, because they have lighter weight, higher energy density, higher power density, and a higher energy-to-weight ratio than other types of batteries. Conventional contact-based cutting technology may be inefficient whenever cell design is changed since lithium-ion battery cells are not standardized. Furthermore, the conventional cutting may result in process instability and a poor cut quality due to the tool wear so that it leads to short circuits and local heat generation. These process instability and inefficiency may be solved by laser cutting due to advantages such as clean cutting edge, less deformation, applicability to almost all materials, possibility of precision processing, and easy modification of cutting path. Despite the importance of the laser cutting research, no clear definition of cutting widths has been presented, and there is lack of knowledge to understand the effect of laser parameters on cutting widths. Therefore, this research examines the surface of cathode cut by a laser and defines cutting widths such as top width, melting width, and kerf width. The relationship between the laser parameters and cutting characteristics with defined widths are studied. When the volume energy is less than 6.0172 × 10 10 J / m 3 , no active electrode material is removed. When the laser power is greater or equal to 100 W, both the top and melting widths are clearly observed. The laser power of 50 W can selectively ablate the active electrode material with the material removal rate of 32.14–55.71 mm 3 / min . The threshold volume energy to fully penetrate the 50 μm-thick current collector is between 9.6275 × 10 10 – 8.0229 × 10 10 J / m 3 . All clearance width is less than 20 μm, while the clearance width interestingly exceeds 20 μm when the laser power is 200 W. The effect of material properties on heat transfer using the one dimensional transient semi-infinite conduction model is investigated. In addition, five types of physical characteristics are defined and discussed.
      Citation: Applied Sciences
      PubDate: 2017-09-06
      DOI: 10.3390/app7090914
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 915: Ultrashort Free-Electron Laser X-ray
           Pulses

    • Authors: Wolfram Helml, Ivanka Grguraš, Pavle Juranić, Stefan Düsterer, Tommaso Mazza, Andreas Maier, Nick Hartmann, Markus Ilchen, Gregor Hartmann, Luc Patthey, Carlo Callegari, John Costello, Michael Meyer, Ryan Coffee, Adrian Cavalieri, Reinhard Kienberger
      First page: 915
      Abstract: For the investigation of processes happening on the time scale of the motion of bound electrons, well-controlled X-ray pulses with durations in the few-femtosecond and even sub-femtosecond range are a necessary prerequisite. Novel free-electron lasers sources provide these ultrashort, high-brightness X-ray pulses, but their unique aspects open up concomitant challenges for their characterization on a suitable time scale. In this review paper we describe progress and results of recent work on ultrafast pulse characterization at soft and hard X-ray free-electron lasers. We report on different approaches to laser-assisted time-domain measurements, with specific focus on single-shot characterization of ultrashort X-ray pulses from self-amplified spontaneous emission-based and seeded free-electron lasers. The method relying on the sideband measurement of X-ray electron ionization in the presence of a dressing optical laser field is described first. When the X-ray pulse duration is shorter than half the oscillation period of the streaking field, few-femtosecond characterization becomes feasible via linear streaking spectroscopy. Finally, using terahertz fields alleviates the issue of arrival time jitter between streaking laser and X-ray pulse, but compromises the achievable temporal resolution. Possible solutions to these remaining challenges for single-shot, full time–energy characterization of X-ray free-electron laser pulses are proposed in the outlook at the end of the review.
      Citation: Applied Sciences
      PubDate: 2017-09-06
      DOI: 10.3390/app7090915
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 916: Ion-Mediated Aggregation of Gold
           Nanoparticles for Light-Induced Heating

    • Authors: David Alba-Molina, María Martín-Romero, Luis Camacho, Juan Giner-Casares
      First page: 916
      Abstract: Photothermal therapy is proposed as a straightforward manner of killing cancer cells, which a plasmon field of gold nanoparticles is activated by incoming light resonance leading to a local increase of temperature. This photothermal effect is strongly dependent on the plasmonic features of the nanoparticles. Herein, we study the effect of the ion-mediated aggregation of citrate-capped small spherical gold nanoparticles on the plasmonic band and the photothermal performance. An intermediate value of ionic strength has been found to be optimum with respect to the photothermal capabilities of the gold nanoparticles.
      Citation: Applied Sciences
      PubDate: 2017-09-07
      DOI: 10.3390/app7090916
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 917: A Review of Mixture Theory for
           Deformable Porous Media and Applications

    • Authors: Javed Siddique, Aftab Ahmed, Asim Aziz, Chaudry Khalique
      First page: 917
      Abstract: Mixture theory provides a continuum framework to model a multi-phase system. The basic assumption is, at any instant of time all phases are present at every material point and momentum and mass balance equations are postulated. This paper reviews the recent developments in mixture theory and focuses on the applications of the theory in particular areas of biomechanics, composite manufacturing and infiltration into deformable porous materials. The complexity based upon different permeability and stress functions is also addressed. The review covers the literature presented in the past fifty years and summarizes applications of mixture theory in specific areas of interest, for the sake of brevity, only necessary details are provided rather than complete modeling and simulation.
      Citation: Applied Sciences
      PubDate: 2017-09-09
      DOI: 10.3390/app7090917
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 918: Simulation of Tail Boom Vibrations
           Using Main Rotor-Fuselage Computational Fluid Dynamics (CFD)

    • Authors: Andrey Batrakov, Alexander Kusyumov, Sergey Kusyumov, Sergey Mikhailov, George Barakos
      First page: 918
      Abstract: In this work, fully-resolved rotor-fuselage interactional aerodynamics is used as the forcing term in a model based on the Euler-Bernoulli equation, aiming to simulate helicopter tail-boom vibration. The model is based on linear beam analysis and captures the effect of the blade-passing as well as the effect of the changing force direction on the boom. The Computational Fluid Dynamics (CFD) results were obtained using a well-validated helicopter simulation tool. Results for the tail-boom vibration are not validated due to lack of experimental data, but were obtained using an established analytical approach and serve to demonstrate the strong effect of aerodynamics on tail-boom aeroelastic behavior.
      Citation: Applied Sciences
      PubDate: 2017-09-07
      DOI: 10.3390/app7090918
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 919: Flow Characteristics of Steam and Gas
           Push in the Presence of Heat Thief Zones Overlying Oil Sands Deposits

    • Authors: Changsoo Lee, Changhyup Park, Soobin Park
      First page: 919
      Abstract: This paper presents the effects of the top water-bearing zone on the performance of the steam and gas push, i.e., nitrogen as a non-condensable gas injected with steam into an oil sands deposit. The flow characteristics of fluid mixtures are examined in the presence of different-sized water-bearing formations overlying oil sands deposits, i.e., a finite aquifer with no-flow boundaries and an infinite aquifer with continuous mass flux. The performance efficiency is investigated by respectively implementing the cumulative steam to oil ratio, a simple thermal efficiency parameter, and the oil production on the surface. The top water-bearing area serves as a heat thief zone and negatively impacts bitumen recovery; furthermore, it increases the cumulative steam to oil ratio while decreasing the simple thermal efficiency parameter, as well as the oil production rate. When the steam chamber encounters the top aquifer, a severe heat loss occurs. As increasing mol % of nitrogen, the producing time with energy efficiency increases but the chamber growth is limited. The specific operational conditions would be possible for the finite-sized aquifer, while the continuous water influx and the significant heat loss obstructs the thermal processes for the infinite aquifer.
      Citation: Applied Sciences
      PubDate: 2017-09-07
      DOI: 10.3390/app7090919
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 920: Towards Large-Scale Fast
           Reprogrammable SOA-Based Photonic Integrated Switch Circuits

    • Authors: Ripalta Stabile
      First page: 920
      Abstract: Due to the exponentially increasing connectivity and bandwidth demand from the Internet, the most advanced examples of medium-scale fast reconfigurable photonic integrated switch circuits are offered by research carried out for data- and computer-communication applications, where network flexibility at a high speed and high connectivity are provided to suit network demand. Recently we have prototyped optical switching circuits using monolithic integration technology with up to several hundreds of integrated optical components per chip for high connectivity. In this paper, the current status of fast reconfigurable medium-scale indium phosphide (InP) integrated photonic switch matrices based on the use of semiconductor optical amplifier (SOA) gates is reviewed, focusing on broadband and cross-connecting monolithic implementations, granting a connectivity of up to sixteen input ports, sixteen output ports, and sixty-four channels, respectively. The opportunities for increasing connectivity, enabling nanosecond order reconfigurability, and introducing distributed optical power monitoring at the physical layer are highlighted. Complementary architecture based on resonant switching elements on the same material platform are also discussed for power efficient switching. Performance projections related to the physical layer are presented and strategies for improvements are discussed in view of opening a route towards large-scale power efficient fast reprogrammable photonic integrated switching circuits.
      Citation: Applied Sciences
      PubDate: 2017-09-07
      DOI: 10.3390/app7090920
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 921: Enhancement of Energy Harvesting
           Performance by a Coupled Bluff Splitter Body and PVEH Plate through Vortex
           Induced Vibration near Resonance

    • Authors: Wei Chin, Zhi Ong, Keen Kong, Shin Khoo, Yu-Hsi Huang, Wen Chong
      First page: 921
      Abstract: Inspired by vortex induced vibration energy harvesting development as a new source of renewable energy, a T-shaped design vibration energy harvester is introduced with the aim of enhancing its performance through vortex induced vibration at near resonance conditions. The T-shaped structural model designed consists of a fixed boundary aluminum bluff splitter body coupled with a cantilever piezoelectric vibration energy harvesters (PVEH) plate model which is a piezoelectric bimorph plate made of a brass plate sandwiched between 2 lead zirconate titanate (PZT) plates. A 3-dimensional Fluid-Structure Interaction simulation analysis is carried out with Reynolds Stress Turbulence Model under wind speed of 7, 10, 12, 14, 16, 18, 19, 20, 22.5, and 25 m/s. The results showed that with 19 m/s wind speed, the model generates 75.758 Hz of vortex frequency near to the structural model’s natural frequency of 76.9 Hz. Resonance lock-in therefore occurred, generating a maximum displacement amplitude of 2.09 mm or a 49.76% increment relatively in vibrational amplitude. Under the effect of resonance at the PVEH plate’s fundamental natural frequency, it is able to generate the largest normalized power of 13.44 mW/cm3g2.
      Citation: Applied Sciences
      PubDate: 2017-09-07
      DOI: 10.3390/app7090921
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 922: Near-Infrared Spectroscopy Applied to
           Complex Systems and Human Hyperscanning Networking

    • Authors: Davide Crivelli, Michela Balconi
      First page: 922
      Abstract: Concepts and techniques developed to investigate complex systems have found practical implications in the study of many complex physical, biological, and social phenomena. Social neuroscience is coherently moving to new investigation and analysis approaches to properly explore social dynamics and to qualify neural processes that mediate and define them. The present paper aims to sketch a global picture of the application of the concept of synchronization to study complex social systems and the neural signatures of interpersonal coupling during interaction dynamics. We then focus on an innovative experimental paradigm—hyperscanning—that allows researchers to sample, compare, and integrate information flows related to the bodily activities of two (or more) individuals involved in a shared naturalistic or experimentally-controlled task, thus giving the opportunity to explore inter-individual synchronization and inter-brain coupling. In particular, the potential of functional Near-Infrared Spectroscopy (fNIRS) as a primary investigation tool in the field is discussed. Finally, we introduce the most-used quantification and analysis methods for hyperscanning applications.
      Citation: Applied Sciences
      PubDate: 2017-09-08
      DOI: 10.3390/app7090922
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 923: Real-Time Transportation Mode
           Identification Using Artificial Neural Networks Enhanced with Mode
           Availability Layers: A Case Study in Dubai

    • Authors: Young-Ji Byon, Jun Ha, Chung-Suk Cho, Tae-Yeon Kim, Chan Yeun
      First page: 923
      Abstract: Traditionally, departments of transportation (DOTs) have dispatched probe vehicles with dedicated vehicles and drivers for monitoring traffic conditions. Emerging assisted GPS (AGPS) and accelerometer-equipped smartphones offer new sources of raw data that arise from voluntarily-traveling smartphone users provided that their modes of transportation can correctly be identified. By introducing additional raster map layers that indicate the availability of each mode, it is possible to enhance the accuracy of mode detection results. Even in its simplest form, an artificial neural network (ANN) excels at pattern recognition with a relatively short processing timeframe once it is properly trained, which is suitable for real-time mode identification purposes. Dubai is one of the major cities in the Middle East and offers unique environments, such as a high density of extremely high-rise buildings that may introduce multi-path errors with GPS signals. This paper develops real-time mode identification ANNs enhanced with proposed mode availability geographic information system (GIS) layers, firstly for a universal mode detection and, secondly for an auto mode detection for the particular intelligent transportation system (ITS) application of traffic monitoring, and compares the results with existing approaches. It is found that ANN-based real-time mode identification, enhanced by mode availability GIS layers, significantly outperforms the existing methods.
      Citation: Applied Sciences
      PubDate: 2017-09-08
      DOI: 10.3390/app7090923
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 924: Low-Cost Nanocarbon-Based Peroxidases
           from Graphite and Carbon Fibers

    • Authors: Yan Zeng, Feifan Miao, Zhiyong Zhao, Yuting Zhu, Tao Liu, Rongsheng Chen, Simin Liu, Zaosheng Lv, Feng Liang
      First page: 924
      Abstract: A low-cost and facile preparation of water-soluble carbon nanomaterials from commercial available graphite and polypropylene carbon fibers was achieved. N-doped graphene quantum dot was also prepared as a comparable agent. The resultant carbon nanomaterials were characterized by vital techniques such as transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis absorption, Fourier transform infrared (FT-IR) and Raman spectra. The prepared carbon nanomaterials can make hydrogen peroxide degradation produce hydroxyl radicals, thus possess intrinsic peroxidase-like activity for colorimetric and UV-vis absorption detection of hydrogen peroxide. These carbon nanomaterials exhibit excellent sensitivity toward hydrogen peroxide with the limit of detection as low as 0.024 mM (by Carbon nanomaterials-1 from carbon fibers), 0.0042 mM (by Carbon nanomaterials-2 from graphite) and 0.014 mM (by Carbon nanomaterials-3 from nitrogen doped graphene oxide), respectively. The practical use of these carbon nanomaterials for phenolic compounds removal in aqueous solution is also demonstrated successfully. The extraordinary catalytic performance and low cost of these carbon nanomaterials make them a powerful tool for a wide range of potential applications.
      Citation: Applied Sciences
      PubDate: 2017-09-08
      DOI: 10.3390/app7090924
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 925: An Event Reporting and Early-Warning
           Safety System Based on the Internet of Things for Underground Coal Mines:
           A Case Study

    • Authors: Byung Jo, Rana Khan
      First page: 925
      Abstract: Fatal accidents associated with underground coal mines require the implementation of high-level gas monitoring and miner’s localization approaches to promote underground safety and health. This study introduces a real-time monitoring, event-reporting and early-warning platform, based on cluster analysis for outlier detection, spatiotemporal statistical analysis, and an RSS range-based weighted centroid localization algorithm for improving safety management and preventing accidents in underground coal mines. The proposed platform seamlessly integrates monitoring, analyzing, and localization approaches using the Internet of Things (IoT), cloud computing, a real-time operational database, application gateways, and application program interfaces. The prototype has been validated and verified at the operating underground Hassan Kishore coal mine. Sensors for air quality parameters including temperature, humidity, CH4, CO2, and CO demonstrated an excellent performance, with regression constants always greater than 0.97 for each parameter when compared to their commercial equivalent. This framework enables real-time monitoring, identification of abnormal events (>90%), and verification of a miner’s localization (with <1.8 m of error) in the harsh environment of underground mines. The main contribution of this study is the development of an open source, customizable, and cost-effective platform for effectively promoting underground coal mine safety. This system is helpful for solving the problems of accessibility, serviceability, interoperability, and flexibility associated with safety in coal mines.
      Citation: Applied Sciences
      PubDate: 2017-09-08
      DOI: 10.3390/app7090925
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 926: Detecting Anatomical Leg Length
           Discrepancy Using the Plug-in-Gait Model

    • Authors: Sam Khamis, Barry Danino, Shmuel Springer, Dror Ovadia, Eli Carmeli
      First page: 926
      Abstract: Leg length discrepancy (LLD) is a significant factor influencing several pathological conditions. Gait analysis is based on biomechanical gait models calculating joint kinematics; however, no previous study has validated its ability to detect anatomical LLD. The aim of the present study was to compare the validity of the Vicon® Plug-in-Gait-model (PGM) in measuring femur and tibia segmental length discrepancy with measurements attained by X-ray. Fifteen participants with suspected leg length discrepancies underwent a lower limb X-ray and a standing calibration trial using a motion analysis system (Vicon®, Oxford Metrics, UK). Femur and tibia segment lengths were deducted from both measurements. No differences were found when measuring the discrepancies between sides for the femur (p = 0.3) and tibia (p = 0.45) segmental length. A high correlation was found between methods (r = 0.808–0.962, p < 0.001), however, a significant difference was observed when measuring the femur and tibia length (p < 0.0001). PGM was found to be a valid model in detecting segmental length discrepancy when based on the location of the joint centers compared to X-ray. A variance was noted in the femur and tibial segmental length. The impact of this inconsistency in segmental length on kinematics and kinetics should be further evaluated.
      Citation: Applied Sciences
      PubDate: 2017-09-08
      DOI: 10.3390/app7090926
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 927: Optimal Control and Operation
           Strategy for Wind Turbines Contributing to Grid Primary Frequency
           Regulation

    • Authors: Mun-Kyeom Kim
      First page: 927
      Abstract: This study introduces a frequency regulation strategy to enable the participation of wind turbines with permanent magnet synchronous generators (PMSGs). The optimal strategy focuses on developing the frequency support capability of PMSGs connected to the power system. Active power control is performed using maximum power point tracking (MPPT) and de-loaded control to supply the required power reserve following a disturbance. A kinetic energy (KE) reserve control is developed to enhance the frequency regulation capability of wind turbines. The coordination with the de-loaded control prevents instability in the PMSG wind system due to excessive KE discharge. A KE optimization method that maximizes the sum of the KE reserves at wind farms is also adopted to determine the de-loaded power reference for each PMSG wind turbine using the particle swarm optimization (PSO) algorithm. To validate the effectiveness of the proposed optimal control and operation strategy, three different case studies are conducted using the PSCAD/EMTDC simulation tool. The results demonstrate that the optimal strategy enhances the frequency support contribution from PMSG wind turbines.
      Citation: Applied Sciences
      PubDate: 2017-09-08
      DOI: 10.3390/app7090927
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 928: Agent-Based Model for Automaticity
           Management of Traffic Flows across the Network

    • Authors: Karina Raya-Díaz, Carelia Gaxiola-Pacheco, Manuel Castañón-Puga, Luis Palafox, Juan Castro, Dora-Luz Flores
      First page: 928
      Abstract: This paper presents an agent-based model that performs the management of traffic flows in a network with the purpose of observing in a simulation of distinctive congestion scenarios how the automation of the monitoring task improves the network performance. The model implements a decision-making algorithm to determine the path that the data flows will follow to reach their destination, according to the results of the negotiation between the agents. In addition, we explain how the behavior of the network is affected by its topology. The aim of this paper is to propose an agent-based model that simplifies the management of the traffic flows in a communications network towards the automaticity of the system.
      Citation: Applied Sciences
      PubDate: 2017-09-09
      DOI: 10.3390/app7090928
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 929: High Performance MRAM with
           Spin-Transfer-Torque and Voltage-Controlled Magnetic Anisotropy Effects

    • Authors: Hao Cai, Wang Kang, You Wang, Lirida Naviner, Jun Yang, Weisheng Zhao
      First page: 929
      Abstract: The Internet of Things (IoTs) relies on efficient node memories to process data among sensors, cloud and RF front-end. Both mainstream and emerging memories have been developed to achieve this energy efficiency target. Spin transfer torque magnetic tunnel junction (STT-MTJ)-based nonvolatile memory (NVM) has demonstrated great performance in terms of zero standby power, switching power efficiency, infinite endurance and high density. However, it still has a big performance gap; e.g., high dynamic write energy, large latency, yield and reliability. Recently, voltage-controlled magnetic anisotropy (VCMA) has been introduced to achieve improved energy-delay efficiency and robust non-volatile writing control with an electric field or a switching voltage. VCMA-MTJ-based MRAM could be a promising candidate in IoT node memory for high-performance, ultra-low power consumption targets.
      Citation: Applied Sciences
      PubDate: 2017-09-11
      DOI: 10.3390/app7090929
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 930: Air Entrainment and Air Demand in the
           Spillway Tunnel at the Jinping-I Dam

    • Authors: Jijian Lian, Chunfeng Qi, Fang Liu, Wenjuan Gou, Shunqi Pan, Qunan Ouyang
      First page: 930
      Abstract: Artificial air entrainment has been widely used to avoid cavitation damage in spillways where high-velocity flow occurs, and its performance is very important for spillway safety. In order to evaluate the performance of the aeration system in the spillway tunnel of the Jinping-I Dam, which is the highest arched dam in the world to date, systematic prototype observation was conducted. Ventilation characteristics of the air supply system and aeration-related characteristics of the aeration devices were examined at the prototype scale. The results showed that air flows smoothly in the air intake well and the real effect of air entrainment of the aeration device was desirable. In contrast with results from laboratory tests with a physical model at a scale of 1/30 following the gravity similarity, it was found that air demand in the prototype is much greater, clearly indicating the scale effect. By summing up and analyzing the air demand ratio of the prototype to the model in some projects, the scale effect was found to be ignorable when the model scale was greater than 1/10. In addition, based on a series of prototype data on air demand, a brief evaluation of present calculation methods for air demand was conducted and a new form of calculation method for air demand related to unit width flow rate was established. The present prototype results can be used as a reference for similar engineering design, and to validate and verify numerical simulations as well as model tests.
      Citation: Applied Sciences
      PubDate: 2017-09-10
      DOI: 10.3390/app7090930
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 931: Changes in Pore Structure of Coal
           Associated with Sc-CO2 Extraction during CO2-ECBM

    • Authors: Run Chen, Yong Qin, Chongtao Wei, Linlin Wang, Youyang Wang, Pengfei Zhang
      First page: 931
      Abstract: Supercritical CO2 (Sc-CO2), a supercritical solvent, can extract small organic molecules (fluid) from coal, changing pore structures to affect gases storage and migration in the coal matrix. Five undeformed coals before and after the second coalification jump were collected to simulate Sc-CO2 extraction performed with supercritical extraction equipment. Pore structures of the samples before and after Sc-CO2 extraction were characterized using mercury porosimetry. The results show that there are significant changes in pore size distribution of samples. ΔVMa and ΔVMe of coal samples are positive, ΔVTr and ΔVMi are positive for most coals, and ΔVMi of higher coals are negative; the ΔSMa and ΔSMe are positive with small values, the ΔSTr and ΔSMi are positive and negative before and after the second coalification jump; thus, the pore connectivity is improved. These results indicate that Sc-CO2 extraction not only increases the numbers of micropores, but also enlarges the pore diameter size; these changes in the pore structure are influenced by the second coalification. The changes in the pore structure by Sc-CO2 extraction provide more spaces for gas storage and may improve the pore throats for gas migration.
      Citation: Applied Sciences
      PubDate: 2017-09-10
      DOI: 10.3390/app7090931
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 932: Frequency Modulation and Erosion
           Performance of a Self-Resonating Jet

    • Authors: Wenchuan Liu, Yong Kang, Mingxing Zhang, Yongxiang Zhou, Xiaochuan Wang, Deng Li
      First page: 932
      Abstract: The self-resonating water jet offers the advantages of both a cavitation jet and a pulsed jet, and thus has been widely used for many practical applications. In the present study, the 120° -impinging edge Helmholtz nozzle was investigated for better erosion performance. The oscillating mechanism was analyzed from both numerical and experimental perspectives. The results showed that the cavitation clouds in the chamber dominate the oscillating frequency. The frequency resulting from the non-linear interaction was also observed in the simulation. The dominant frequency increases linearly as pressure decreases without entrained air. The frequency modulation was achieved through various inspiratory methods, and the modulation range was dependent on the pressure drop. The erosion performance was improved with entrained air, and the improvement was effected by the inspiratory method. The oscillating frequency was determined by the forced frequency of entrained air, and the best erosion performance was achieved at the frequency closest to the fundamental frequency. A feasible method to improve the erosion performance was investigated in this preliminary study, which could provide a guide for practical applications.
      Citation: Applied Sciences
      PubDate: 2017-09-10
      DOI: 10.3390/app7090932
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 933: Measurement Matrix Analysis and
           Radiation Improvement of a Metamaterial Aperture Antenna for Coherent
           Computational Imaging

    • Authors: Na Kou, Long Li, Shuncheng Tian, Yuanchang Li
      First page: 933
      Abstract: A metamaterial aperture antenna (MAA) that generates frequency-diverse radiation field patterns has been introduced in the context of microwave wave imaging to perform compressive image reconstruction. This paper presents a new metamateriapl aperture design, which includes two kinds of metamaterial elements with random distribution. One is a high-Q resonant element whose resonant frequency is agile, and the other one is a low-Q element that has a high radiation efficiency across frequency band. Numerical simulations and measurements show that the radiation efficiency of up to 60% can be achieved for the MAA and the far-field patterns owns good orthogonality, when using the complementary electric-field-coupled (CELC) element and the complementary Jerusalem cross (CJC) element with a random distribution ratio of 4 to 1, which could be effectively used to reconstruct the target scattering scene.
      Citation: Applied Sciences
      PubDate: 2017-09-12
      DOI: 10.3390/app7090933
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 934: Experimental Study on Milling CFRP
           with Staggered PCD Cutter

    • Authors: Tao Chen, Daoyuan Wang, Fei Gao, Xianli Liu
      First page: 934
      Abstract: Carbon fiber reinforced plastics (CFRP) have good physical properties, such as high specific strength and high specific modulus. However, cutting delamination, tearing and burr, etc. often occur in the machining process of CFRP, which results in the uncontrollability of machining surface quality and serious tool wear. In this paper, milling of CFRP with a staggered cutter was carried out, the cutting-edge radius was investigated in order to characterize the tool wear; the effect of the cutting-edge wear radius on the milling force and surface quality was found, and the formation mechanisms of the 3D surface topography and surface defects were analyzed under the wear state. Experimental results showed that the wear of the staggered PCD cutter was mainly concentrated in the cutting-edge area. With the increase in milling length, the radius of cutting edge gradually became largeer under the action of abrasive wear mechanism, and the flank wear was not obvious. With the intension of tool wear, milling force gradually increased and the machining surface quality of the CFRP deteriorated distinctly, i.e., defects such as bare fiber fracture, groove and hole appeared, and burrs were gradually generated on the workpiece surface. Finally, through a comparative analysis of cutting performance, it was found that the staggered PCD cutter possessed better performance for wear resistance and burr suppression than the straight-teeth cutter. This finding can provide theoretical and technical support for improving the machining quality of carbon fiber composite materials.
      Citation: Applied Sciences
      PubDate: 2017-09-11
      DOI: 10.3390/app7090934
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 935: Analysis of the Pyroclastic Flow
           Deposits of Mount Sinabung and Merapi Using Landsat Imagery and the
           Artificial Neural Networks Approach

    • Authors: Prima Kadavi, Won-Jin Lee, Chang-Wook Lee
      First page: 935
      Abstract: Volcanic eruptions cause pyroclastic flows, which can destroy plantations and settlements. We used image data from Landsat 7 Bands 7, 4 and 2 and Landsat 8 Bands 7, 5 and 3 to observe and analyze the distribution of pyroclastic flow deposits for two volcanos, Mount Sinabung and Merapi, over a period of 10 years (2001–2017). The satellite data are used in conjunction with an artificial neural network method to produce maps of pyroclastic precipitation for Landsat 7 and 8, then we calculated the pyroclastic precipitation area using an artificial neural network method after dividing the images into four classes based on color. Red, green, blue and yellow were used to indicate pyroclastic deposits, vegetation and forest, water and cloud, and farmland, respectively. The area affected by a volcanic eruption was deduced from the neural network processing, including calculating the area of pyroclastic deposits. The main differences between the pyroclastic flow deposits of Mount Sinabung and Mount Merapi are: the sediment deposits of the pyroclastic flows of Mount Sinabung tend to widen, whereas those of Merapi elongated; the direction of pyroclastic flow differed; and the area affected by an eruption was greater for Mount Merapi than Mount Sinabung because the VEI (Volcanic Explosivity Index) during the last 10 years of Mount Merapi was larger than Mount Sinabung.
      Citation: Applied Sciences
      PubDate: 2017-09-11
      DOI: 10.3390/app7090935
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 936: Localization in Low Power Wide Area
           Networks Using Wi-Fi Fingerprints

    • Authors: Thomas Janssen, Maarten Weyn, Rafael Berkvens
      First page: 936
      Abstract: Supply chain management requires regular updates of the location of assets, which can be enabled by low power wide area networks, such as Sigfox. While it is useful to localize a device simply by its communication signals, this is very difficult to do with Sigfox because of wide area and ultra narrowband nature. On the other hand, installing a satellite localization element on the device greatly increases its power consumption. We investigated using information about nearby Wi-Fi access points as a way to localize the asset over the Sigfox network, so without connecting to those Wi-Fi networks. This paper reports the location error that can be achieved by this type of outdoor localization. By using a combination of two databases, we could localize the device on all 36 test locations with a median location error of 39 m . This shows that the localization accuracy of this method is promising enough to warrant further study, most specifically the minimal power consumption.
      Citation: Applied Sciences
      PubDate: 2017-09-12
      DOI: 10.3390/app7090936
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 937: Weak Fault Feature Extraction Scheme
           for Intershaft Bearings Based on Linear Prediction and Order Tracking in
           the Rotation Speed Difference Domain

    • Authors: Zhinong Jiang, Minghui Hu, Kun Feng, Ya He
      First page: 937
      Abstract: Because both the inner and outer rings rotate, the intershaft bearings used in gas turbines do not have fixed bearing housings. As a result, the vibration of intershaft bearings cannot be measured directly. Therefore, a vibration signal can only be collected through indirect measurement. First, it must be transferred to adjacent bearings through the shafting. Then, it should be transferred by the elastic supports and complex structure of the thin-walled strut. The vibration signal is severely weakened during transmission under the influences of the transfer path. In the meantime, in the vibration of other components, a huge amount of noise is produced by the air flow, and the variable speeds of the inner and outer rings of the intershaft bearings make it harder to analyze the signal. Hence, it is very difficult to extract the vibration fault features of intershaft bearings. To deal with the variable speed of dual rotors, as well as the weak signal, a fault feature extraction scheme for the weak fault signals of intershaft bearings is proposed in this paper. This scheme is based on linear prediction, spectral kurtosis, and order tracking in the rotation speed difference domain. First, a prewhitening process, based on linear prediction, is applied to the fault signal of the intershaft bearings to eliminate the stationary component. Thus, the remaining components, including the impulse signal of faulty bearings and nonstationary noise, can retain the features of the vibrational bearings, in addition to reducing the noise. Second, the optimal center frequency and bandwidth of the band-pass filter, applied to resonant demodulation, are selected by spectral kurtosis. Subsequently, the enveloped signal containing the features of the faults found in the intershaft bearings is obtained by resonance demodulation. The quasi-stationary signal in the angle domain is acquired by the even angle resampling of the nonstationary envelope signal, as a result of the variable speed. The final order spectrum is obtained through a Fourier transform. Fault diagnosis can be conducted for the intershaft bearings by comparing this spectrum with the feature order of the bearing fault. Experiments were conducted to verify the validity of the proposed scheme.
      Citation: Applied Sciences
      PubDate: 2017-09-12
      DOI: 10.3390/app7090937
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 938: Ultralow Friction of ZrO2 Ball
           Sliding against DLC Films under Various Environments

    • Authors: Qunfeng Zeng, Ali Erdemir, Osman Erylimaz
      First page: 938
      Abstract: Ultralow friction is achieved by ZrO2 as the friction mate material for DLC (Diamond like carbon) films under various environments. Coefficient of friction (CoF) of ZrO2/DLC films is as ultra low as 0.02 in ambient air at the temperature of 200 °C, and 0.03, 0.04 and 0.05 in hydrogen, nitrogen and vacuum environments at the temperature of 100 °C, respectively. It is concluded that the transferred films are formed on the worn surface of ZrO2 ball and amorphous carbon films. Ultralow friction of the friction pair is related with hydrogen, which is derived from DLC films, hydrogen environment or the liberation hydrogen due to hydrothermal oxidation. The ultralow friction mechanism is attributed to the formation of hydrogenated amorphous carbon films on ZrO2 ball and the shielding action of hydrogen from DLC films and the transferred films simultaneously.
      Citation: Applied Sciences
      PubDate: 2017-09-12
      DOI: 10.3390/app7090938
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 939: Structure and Capacitance of
           Electrical Double Layers at the Graphene–Ionic Liquid Interface

    • Authors: Pengfei Lu, Qiaobo Dai, Liangyu Wu, Xiangdong Liu
      First page: 939
      Abstract: Molecular dynamics simulations are carried out to investigate the structure and capacitance of the electrical double layers (EDLs) at the interface of vertically oriented graphene and ionic liquids [EMIM]+/[BF4]−. The distribution and migration of the ions in the EDL on the rough and non-rough electrode surfaces with different charge densities are compared and analyzed, and the effect of the electrode surface morphology on the capacitance of the EDL is clarified. The results suggest that alternate distributions of anions and cations in several consecutive layers are formed in the EDL on the electrode surface. When the electrode is charged, the layers of [BF4]− anions experience more significant migration than those of [EMIM]+ cations. These ion layers can be extended deeper into the bulk electrolyte solution by the stronger interaction of the rough electrode, compared to those on the non-rough electrode surface. The potential energy valley of ions on the neutral electrode surface establishes a potential energy difference to compensate the energy cost of the ion accumulation, and is capable of producing a potential drop across the EDL on the uncharged electrode surface. Due to the greater effective contact area between the ions and electrode, the rough electrode possesses a larger capacitance than the non-rough one. In addition, it is harder for the larger-sized [EMIM]+ cations to accumulate in the narrow grooves on the rough electrode, when compared with the smaller [BF4]−. Consequently, the double-hump-shaped C–V curve (which demonstrates the relationship between differential capacitance and potential drop across the EDL) for the rough electrode is asymmetric, where the capacitance increases more significantly when the electrode is positively charged.
      Citation: Applied Sciences
      PubDate: 2017-09-12
      DOI: 10.3390/app7090939
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 940: Competitive Evaluation of Planar
           Embedded Glass and Polymer Waveguides in Data Center Environments

    • Authors: Richard Pitwon, Kai Wang, Akira Yamauchi, Takaaki Ishigure, Henning Schröder, Marcel Neitz, Mayank Singh
      First page: 940
      Abstract: Optical printed circuit board (OPCB) waveguide materials and fabrication methods have advanced considerably over the past 15 years, giving rise to two classes of embedded planar graded index waveguide based on polymer and glass. We consider the performance of these two emerging waveguide classes in view of the anticipated deployment in data center environments of optical transceivers based on directly modulated multimode short wavelength VCSELs against those based on longer wavelength single-mode photonic integrated circuits. We describe the fabrication of graded index polymer waveguides, using the Mosquito and photo-addressing methods, and graded index glass waveguides, using ion diffusion on thin glass foils. A comparative characterization was carried out on the waveguide classes to show a clear reciprocal dependence of the performance of different waveguide classes on wavelength. Furthermore, the different waveguide types were connected into an optically disaggregated data switch and storage system to evaluate and validate their suitability for deployment in future data center environments.
      Citation: Applied Sciences
      PubDate: 2017-09-13
      DOI: 10.3390/app7090940
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 941: A New Method for Analysing the
           Pressure Response Delay in a Pneumatic Brake System Caused by the
           Influence of Transmission Pipes

    • Authors: Fan Yang, Gangyan Li, Jian Hua, Xingli Li, Toshiharu Kagawa
      First page: 941
      Abstract: This study aims to propose an analysis method for resolving the pressure response of a pneumatic brake circuit considering the effect of a transmission pipe. Pneumatic brake systems (PBS) are widely used in commercial vehicles. The pressure response characteristic of the PBS is the key factor affecting braking performance. By using the thermodynamics of a variable-quality system, the pressure response model of the brake chamber is established, which includes the dynamic model of the pipe considering the unsteady friction and heat transfer. The partial-differential control equations of pipe are solved by introducing the constrained interpolation profile (CIP) method, and a virtual chamber model is proposed to set the boundary condition so as to solve the pressure response in the brake chamber simultaneously. Thus, the regularity of the brake pressure response is obtained by considering the influence of the pipe. Lastly, the model is verified experimentally. The present study indicates that the main factors that affect the pressure response delay are the pipe length and the combination forms of the sonic conductances of the orifices inlet and outlet. Furthermore, it helps to verify that the CIP method is an effective way of solving the pressure response of a brake circuit because of its high accuracy. The present study serves as a foundation for the design and analysis of a PBS.
      Citation: Applied Sciences
      PubDate: 2017-09-13
      DOI: 10.3390/app7090941
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 942: Open Source 3-D Printed Nutating
           Mixer

    • Authors: Dhwani Trivedi, Joshua Pearce
      First page: 942
      Abstract: As the open source development of additive manufacturing has led to low-cost desktop three-dimensional (3-D) printing, a number of scientists throughout the world have begun to share digital designs of free and open source scientific hardware. Open source scientific hardware enables custom experimentation, laboratory control, rapid upgrading, transparent maintenance, and lower costs in general. To aid in this trend, this study describes the development, design, assembly, and operation of a 3-D printable open source desktop nutating mixer, which provides a fixed 20° platform tilt angle for a gentle three-dimensional (gyrating) agitation of chemical or biological samples (e.g., DNA or blood samples) without foam formation. The custom components for the nutating mixer are designed using open source FreeCAD software to enable customization. All of the non-readily available components can be fabricated with a low-cost RepRap 3-D printer using an open source software tool chain from common thermoplastics. All of the designs are open sourced and can be configured to add more functionality to the equipment in the future. It is relatively easy to assemble and is accessible to both the science education of younger students as well as state-of-the-art research laboratories. Overall, the open source nutating mixer can be fabricated with US$37 in parts, which is 1/10th of the cost of proprietary nutating mixers with similar capabilities. The open source nature of the device allow it to be easily repaired or upgraded with digital files, as well as to accommodate custom sample sizes and mixing velocities with minimal additional costs.
      Citation: Applied Sciences
      PubDate: 2017-09-13
      DOI: 10.3390/app7090942
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 943: Coordinated Control of the Energy
           Router-Based Smart Home Energy Management System

    • Authors: Yingshu Liu, Jun Li, Yao Wu, Feng Zhou
      First page: 943
      Abstract: Home area energy networks will be an essential part of the future Energy Internet in terms of energy saving, demand-side management and stability improvement of the distribution network, while an energy router will be the perfect choice to serve as an intelligent and multi-functional energy interface between the home area energy network and power grid. This paper elaborates on the design, analysis and implementation of coordinated control of the low-voltage energy router-based smart home energy management system (HEMS). The main contribution of this paper is to develop a novel solution to make the energy router technically feasible and practical for the HEMS to make full use of the renewable energy sources (RESs), while maintaining “operational friendly and beneficial” to the power grid. The behaviors of the energy router-based HEMS in correlation with the power grid are investigated, then the coordinated control scheme composed of a reference voltage and current compensation strategy and a fuzzy logic control-based power management strategy is developed. The system model is built on the MATLAB/Simulink platform, simulation results have demonstrated that the presented control scheme is a strong performer in making full use of the RES generations for the HEMS while maintaining the operational stability of the whole system, as well as in collaboration with the power grid to suppress the impact of RES output fluctuations and load consumption variations.
      Citation: Applied Sciences
      PubDate: 2017-09-13
      DOI: 10.3390/app7090943
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 944: Characterization of Surface Ozone
           Behavior at Different Regimes

    • Authors: Nádia Afonso, José Pires
      First page: 944
      Abstract: Previous studies showed that the influence of meteorological variables and concentrations of other air pollutants on O3 concentrations changes at different O3 concentration levels. In this study, threshold models with artificial neural networks (ANNs) were applied to characterize the O3 behavior at an urban site (Porto, Portugal), describing the effect of environmental and meteorological variables on O3 concentrations. ANN characteristics, and the threshold variable and value, were defined by genetic algorithms (GAs). The considered predictors were hourly average concentrations of NO, NO2, and O3, and meteorological variables (temperature, relative humidity, and wind speed) measured from January 2012 to December 2013. Seven simulations were performed and the achieved models considered wind speed (at 4.9 m·s−1), temperature (at 17.5 °C) and NO2 (at 26.6 μg·m−3) as the variables that determine the change of O3 behavior. All the achieved models presented a similar fitting performance: R2 = 0.71–0.72, RMSE = 14.5–14.7 μg·m−3, and the index of agreement of the second order of 0.91. The combined effect of these variables on O3 concentration was also analyzed. This statistical model was shown to be a powerful tool for interpreting O3 behavior, which is useful for defining policy strategies for human health protection concerning this air pollutant.
      Citation: Applied Sciences
      PubDate: 2017-09-14
      DOI: 10.3390/app7090944
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 945: Study of the Direct Metal Deposition
           of AA2024 by ElectroSpark for Coating and Reparation Scopes

    • Authors: Paola Leo, Gilda Renna, Giuseppe Casalino
      First page: 945
      Abstract: ElectroSpark Deposition (ESD) is a pulsed micro-welding process that is capable of depositing wear and corrosion resistance deposit to repair, improve, and to extend the service life of the components and tools. Major new applications have taken place in gas turbine blades and steam turbine blade protection and repair, and in military, medical, metal-working, and recreational equipment applications. In this study, the ESD technique was exploited to fabricate 2024 aluminum alloy deposit on a similar substrate. The deposits were deposited using different process parameters. Heat input was varied on three levels. The outcoming microstructure was analyzed by optical and scanning electron microscopies. The deposit was characterized by the overlapping of layers with a mixed microstructure. The average hardness was independent from the process parameters. Both porosity inside the deposits and cracks at the deposit/substrate interface were detected. The porosity lowered with the heat input and increased the average length of cracks.
      Citation: Applied Sciences
      PubDate: 2017-09-14
      DOI: 10.3390/app7090945
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 946: Synthetic Rock Analogue for
           Permeability Studies of Rock Salt with Mudstone

    • Authors: Hongwu Yin, Hongling Ma, Xiangsheng Chen, Xilin Shi, Chunhe Yang, Maurice Dusseault, Yuhao Zhang
      First page: 946
      Abstract: Knowledge about the permeability of surrounding rock (salt rock and mudstone interlayer) is an important topic, which acts as a key parameter to characterize the tightness of gas storage. The goal of experiments that test the permeability of gas storage facilities in rock salt is to develop a synthetic analogue to use as a permeability model. To address the permeability of a mudstone/salt layered and mixed rock mass in Jintan, Jiangsu Province, synthetic mixed and layered specimens using the mudstone and the salt were fabricated for permeability testing. Because of the gas “slippage effect”, test results are corrected by the Klinkenberg method, and the permeability of specimens is obtained by regression fitting. The results show that the permeability of synthetic pure rock salt is 6.9 × 10−20 m2, and its porosity is 3.8%. The permeability of synthetic mudstone rock is 2.97 × 10−18 m2, with a porosity 17.8%. These results are close to those obtained from intact natural specimens. We also find that with the same mudstone content, the permeability of mixed specimens is about 40% higher than for the layered specimens, and with an increase in the mudstone content, the Klinkenberg permeability increases for both types of specimens. The permeability and mudstone content have a strong exponential relationship. When the mudstone content is below 40%, the permeability increases only slightly with mudstone content, whereas above this threshold, the permeability increases rapidly with mudstone content. The results of the study are of use in the assessment of the tightness of natural gas storage facilities in mudstone-rich rock salt formations in China.
      Citation: Applied Sciences
      PubDate: 2017-09-14
      DOI: 10.3390/app7090946
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 947: Model-Based Design and Evaluation of
           a Brachiating Monkey Robot with an Active Waist

    • Authors: Alex Lo, Yu-Huan Yang, Tsen-Chang Lin, Chen-Wen Chu, Pei-Chun Lin
      First page: 947
      Abstract: We report on the model-based development of a monkey robot that is capable of performing continuous brachiation locomotion on swingable rod, as the intermediate step toward studying brachiation on the soft rope or on horizontal ropes with both ends fixed. The work is different from other previous works where the model or the robot swings on fixed bars. The model, which is composed of two rigid links, was inspired by the dynamic motion of primates. The model further served as the design guideline for a robot that has five degree of freedoms: two on each arm for rod changing and one on the waist to initiate a swing motion. The model was quantitatively formulated, and its dynamic behavior was analyzed in simulation. Further, a two-stage controller was developed within the simulation environment, where the first stage used the natural dynamics of a two-link pendulum-like model, and the second stage used the angular velocity feedback to regulate the waist motion. Finally, the robot was empirically built and evaluated. The experimental results confirm that the robot can perform model-like swing behavior and continuous brachiation locomotion on rods.
      Citation: Applied Sciences
      PubDate: 2017-09-14
      DOI: 10.3390/app7090947
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 948: On the Optimisation of Practical
           Wireless Indoor and Outdoor Microcells Subject to QoS Constraints

    • Authors: Adeola Omorinoye, Quoc-Tuan Vien
      First page: 948
      Abstract: Wireless indoor and outdoor microcells (WIOMs) have emerged as a promising means to deal with a high demand of mobile users for a variety of services. Over such heterogeneous networks, the deployment of WIOMs costs mobile/telecommunications company high capital expenditures and operating expenses. This paper aims at optimising the WIOMs taking into account various network communication environments. We first develop an optimisation problem to minimise the number of cells as well as determining their optimal locations subject to the constraints of the coverage and quality-of-service (QoS) requirements. In particular, we propose a binary-search based cell positioning (BSCP) algorithm to find the optimal number of cells given a preset candidate antenna positions. The proposed BSCP algorithm is shown to not only reduce the number of cells for saving resources but also requires a low computational complexity compared to the conventional approaches with exhaustive search over all available sites. Moreover, EDX SignalPro is exploited as a simulation platform to verify the effectiveness of the proposed BSCP for the WIOMs with respect to various propagation modes and antenna parameters of different types, including isotropic, multiple-input single-output and multiple-input multiple-output.
      Citation: Applied Sciences
      PubDate: 2017-09-15
      DOI: 10.3390/app7090948
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 949: Stochastic Investigation of
           Consolidation Process in Spatially Correlated Heterogeneous Soils

    • Authors: Song-Hun Chong
      First page: 949
      Abstract: Soil consolidation as the dissipation of excess pore water pressure is mainly affected by the relative hydraulic conductivity among the layers. Geostatistical parameters such as the mean, the standard deviation, and the correlation length are physical indicators for each sedimentation and formation history. The effects of spatial variability on the excessive pore water pressure dissipation during consolidation process are investigated using numerical parametric studies, where multiple realizations are tested for selected hydraulic conductivity parameter using lognormal distribution. Numerical simulations show that the greater heterogeneity in hydraulic conductivity distribution applied, the longer time taken for the excess pore water pressure to dissipate, and the longer correlated variability encourages the greater variation in consolidation time. Such differences can be reduced significantly with the coupled drainage allowed by vertical drain method.
      Citation: Applied Sciences
      PubDate: 2017-09-15
      DOI: 10.3390/app7090949
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 950: Decision Support Simulation Method
           for Process Improvement of Intermittent Production Systems

    • Authors: Péter Tamás
      First page: 950
      Abstract: Nowadays production system processes are undergoing sweeping changes. The trends include an increase in the number of product variants to be produced, as well as the reduction of the production’s lead time. These trends were induced by new devices of the industry’s 4.0, namely the Internet of Things and cyber physical systems. The companies have been applying intermittent production systems (job production, batch production) because of the increase in the number of product variants. Consequently, increasing the efficiency of these systems has become especially important. The aim of development in the long term—not achievable in many cases—is the realization of unique production, with mass production’s productivity and lower cost. The improvement of complex production systems can be realized efficiently only through simulation modeling. A standardized simulation method for intermittent production systems has not been elaborated so far. In this paper, I introduce a simulation method for system improvement and present its application possibilities and a practical example.
      Citation: Applied Sciences
      PubDate: 2017-09-15
      DOI: 10.3390/app7090950
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 951: Practical Challenge of Shredded
           Documents: Clustering of Chinese Homologous Pieces

    • Authors: Nan Xing, Jianqi Zhang, Furong Cao, Pengfei Liu
      First page: 951
      Abstract: When recovering a shredded document that has numerous mixed pieces, the difficulty of the recovery process can be reduced by clustering, which is a method of grouping pieces that originally belonged to the same page. Restoring homologous shredded documents (pieces from different pages of the same file) is a frequent problem, and because these pieces have nearly indistinguishable visual characteristics, grouping them is extremely difficult. Clustering research has important practical significance for document recovery because homologous pieces are ubiquitous. Because of the wide usage of Chinese and the huge demand for Chinese shredded document recovery, our research focuses on Chinese homologous pieces. In this paper, we propose a method of completely clustering Chinese homologous pieces in which the distribution features of the characters in the pieces and the document layout are used to correlate adjacent pieces and cluster them in different areas of a document. The experimental results show that the proposed method has a good clustering effect on real pieces. For the dataset containing 10 page documents (a total of 462 pieces), its average accuracy is 97.19%.
      Citation: Applied Sciences
      PubDate: 2017-09-15
      DOI: 10.3390/app7090951
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 952: Study on the High Temperature
           Interfacial Stability of Ti/Mo/Yb0.3Co4Sb12 Thermoelectric Joints

    • Authors: Ming Gu, Shengqiang Bai, Xugui Xia, Xiangyang Huang, Xiaoya Li, Xun Shi, Lidong Chen
      First page: 952
      Abstract: To improve the interfacial stability at high temperatures, n-type skutterudite (SKD) thermoelectric joints with sandwich structures of Ti/Mo/Yb0.3Co4Sb12 were successfully designed and fabricated. In this structure, Mo and Ti were introduced as the barrier layer with the goal of suppressing the interfacial diffusion and the buffer layer with the goal of enhancing the bonding strength, respectively. To evaluate the high temperature interfacial behavior of the Ti/Mo/Yb0.3Co4Sb12 joints, thermal shocking between 0 °C and 600 °C and isothermal aging at a temperature range of 550 °C to 650 °C were carried out in vacuum. During the isothermal aging process, Ti penetrates across the Mo layer, and finally diffuses into the Yb0.3Co4Sb12 matrix. By increasing the isothermal aging time, Ti continuously diffuses and reacts with the elements of Sb and Co in the matrix, consequently forming the multilayer-structured intermetallic compounds of Ti3Sb/Ti2Sb/TiCoSb. Diffusion kinetics was investigated and it was found that the interfacial evolution of the Ti/Mo/Yb0.3Co4Sb12 joints was a diffusion-controlling process. During the diffusion process, the formed Mo-Ti buffer layer acts as a damper, which greatly decelerates the diffusion of Ti towards the Yb0.3Co4Sb12 matrix at high temperatures. Meanwhile, it was found that the increase in the contact resistivity of the joints mainly derives from the inter-diffusion between Ti and Yb0.3Co4Sb12. As a result, the Ti/Mo/Yb0.3Co4Sb12 joint demonstrates the excellent stability of the interfacial contact resistivity. Service life prediction was made based on the stability of the contact resistivity, and it was found that the Ti/Mo/Yb0.3Co4Sb12 joint is qualified for practical applications at 550 °C.
      Citation: Applied Sciences
      PubDate: 2017-09-15
      DOI: 10.3390/app7090952
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 953: Pt-Based Nanostructures for Observing
           Genuine SERS Spectra of p-Aminothiophenol (PATP) Molecules

    • Authors: Yinong Wang, Haofei Zhao, En Cao, Yinghui Sun, Huanyu Ye, Weihua Lin, Rongming Wang
      First page: 953
      Abstract: By one-pot wet chemical method, Pt-based hollow nanostructures were synthesized at room temperature. Because of the highly damping optical response of the metal, these Pt-based hollow nanostructures exhibited weak thermal effects with a laser focal spot on 4-aminothiophenol (PATP) molecules limiting dimerisation. The isolated surface enhanced Raman scattering (SERS) spectra of PATP, in which the vibrational bands from 4,4′-dimercaptoazobenzene (DMAB) molecules are not observed, were able to be seen, and this was in good agreement with the Raman spectra of PATP powder. In addition, the concentration of PATP molecules was varied, and the illumination time was increased to 2000 s, respectively. It was found that spectra were stable with varied PATP concentrations, and the plasmon-driven chemical conversion of PATP to DMAB was still suppressed, even when the laser illumination time was increased to 2000 s.
      Citation: Applied Sciences
      PubDate: 2017-09-15
      DOI: 10.3390/app7090953
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 954: Computational Algorithms Underlying
           the Time-Based Detection of Sudden Cardiac Arrest via Electrocardiographic
           Markers

    • Authors: Annmarie Raka, Ganesh Naik, Rifai Chai
      First page: 954
      Abstract: Early detection of sudden cardiac arrest (SCA) is critical to prevent serious repercussion such as irreversible neurological damage and death. Currently, the most effective method involves analyzing electrocardiogram (ECG) features obtained during ventricular fibrillation. In this study, data from 10 normal patients and 10 SCA patients obtained from Physiobank were used to statistically compare features, such as heart rate, R-R interval duration, and heart rate variability (HRV) features from which the HRV features were then selected for classification via linear discriminant analysis (LDA) and linear and fine Gaussian support vector machines (SVM) in order to determine the ideal time-frame in which SCA can be accurately detected. The best accuracy was obtained at 2 and 8 min prior to SCA onset across all three classifiers. However, accuracy rates of 75–80% were also obtained at time-frames as early as 50 and 40 min prior to SCA onset. These results are clinically important in the field of SCA, as early detection improves overall patient survival.
      Citation: Applied Sciences
      PubDate: 2017-09-16
      DOI: 10.3390/app7090954
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 955: CO2 with Mechanical Subcooling vs.
           CO2 Cascade Cycles for Medium Temperature Commercial Refrigeration
           Applications Thermodynamic Analysis

    • Authors: Laura Nebot-Andrés, Rodrigo Llopis, Daniel Sánchez, Jesús Catalán-Gil, Ramón Cabello
      First page: 955
      Abstract: A recent trend to spread the use of CO2 refrigeration cycles in warm regions of the world is to combine a CO2 cycle with another one using a high performance refrigerant. Two alternatives are being considered: cascade and mechanical subcooling systems. Both respond to a similar configuration of the refrigeration cycle, they being based on the use of two compressors and same number of heat exchangers. However, the compressor, heat exchanger sizes and energy performance differ a lot between them. This work, using experimental relations for CO2 and R1234yf semi-hermetic compressors analyzes in depth both alternatives under the warm climate of Spain. In general, it was concluded that the CO2 refrigeration solution with mechanical subcooling would cover all the conditions with high overall energy efficiency, thus it being recommended for further extension of the CO2 refrigeration applications.
      Citation: Applied Sciences
      PubDate: 2017-09-16
      DOI: 10.3390/app7090955
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 956: ECOAL Project—Delivering Solutions
           for Integrated Monitoring of Coal-Related Fires Supported on Optical Fiber
           Sensing Technology

    • Authors: Joana Ribeiro, Duarte Viveiros, João Ferreira, Alexia Lopez-Gil, Alejandro Dominguez-Lopez, Hugo Martins, Rosa Perez-Herrera, Aitor Lopez-Aldaba, Lia Duarte, Ana Pinto, Sonia Martin-Lopez, Hardy Baierl, Raphael Jamier, Sébastien Rougier, Jean-Louis Auguste, Ana Teodoro, José Gonçalves, Oscar Esteban, José Santos, Philippe Roy, Manuel Lopez-Amo, Miguel Gonzalez-Herraez, José Baptista, Deolinda Flores
      First page: 956
      Abstract: The combustion of coal wastes resulting from mining is of particular environmental concern, and the importance of proper management involving real-time assessment of their status and identification of probable evolution scenarios is recognized. Continuous monitoring of the combustion temperature and emission levels of certain gases allows for the possibility of planning corrective actions to minimize their negative impact on the surroundings. Optical fiber technology is well suited to this purpose and here we describe the main attributes and results obtained from a fiber optic sensing system projected to gather data on distributed temperature and gas emissions in these harsh environments.
      Citation: Applied Sciences
      PubDate: 2017-09-16
      DOI: 10.3390/app7090956
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 957: An On-Line Oxygen Forecasting System
           

    • Authors: Yongjun Zhang, Chengguo Wang, Liu Yan, Daoliang Li, Xiaoshuan Zhang
      First page: 957
      Abstract: Accurate prediction of forthcoming oxygen concentration during waterless live fish transportation plays a key role in reducing the abnormal occurrence, increasing the survival rate in delivery operations, and optimizing manufacturing costs. The most effective ambient monitoring techniques that are based on the analysis of historical process data when performing forecasting operations do not fully consider current ambient influence. This is likely lead to a greater deviation in on-line oxygen level forecasting in real situations. Therefore, it is not advisable for the system to perform early warning and on-line air adjustment in delivery. In this paper, we propose a hybrid method and its implementation system that combines a gray model (GM (1, 1)) with least squares support vector machines (LSSVM) that can be used effectively as a forecasting model to perform early warning effectively according to the dynamic changes of oxygen in a closed system. For accurately forecasting of the oxygen level, the fuzzy C-means clustering (FCM) algorithm was utilized for classification according to the flatfish’s physical features—i.e., length and weight—for more pertinent training. The performance of the gray model-particle swarm optimization-least squares support vector machines (GM-PSO-LSSVM) model was compared with the traditional modeling approaches of GM (1, 1) and LSSVM by applying it to predict on-line oxygen level, and the results showed that its predictions were more accurate than those of the LSSVM and grey model. Therefore, it is a suitable and effective method for abnormal condition forecasting and timely control in the waterless live transportation of flatfish.
      Citation: Applied Sciences
      PubDate: 2017-09-18
      DOI: 10.3390/app7090957
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 958: Gas Sensor Design Based on a Line
           Locked Tunable Fiber Laser and the Dual Path Correlation Spectroscopy
           Method

    • Authors: Everardo Vargas-Rodriguez, Ana Guzman-Chavez, Raja Raja-Ibrahim, Luis Cardoso-Lozano
      First page: 958
      Abstract: In this work a hybrid gas sensor based on a tunable fiber laser and a correlation spectroscopy technique is presented. The laser is tuned by varying the temperature of a bulk silicon wafer of 85 μ m thickness and, once the desired wavelength is reached the line, is locked by keeping fixed its temperature. According to experimental results the wafer temperature variation was in the order of 0.02 K, which induced an estimated wavelength deviation of 0.12 pm, which satisfies the high wavelength position accuracy required for gas sensing applications. Additionally, it is shown that errors due to laser intensity fluctuations can be minimized by implementing a simple dual path correlation spectroscopy stage. As a proof of the suitability of our tunable fiber laser for gas sensing applications, a C2H2 sensor was implemented. By using a 10 cm gas cell at atmospheric pressure, it was possible to detect concentrations from 0 to 20% with a sensitivity of 521 ppm and sub-minute time response. Moreover, the experimental measurements and simulated results have a high level of agreement. Finally, it is important to point out that, by using doped fiber with different characteristics, other wavelength emissions can be generated.
      Citation: Applied Sciences
      PubDate: 2017-09-19
      DOI: 10.3390/app7090958
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 959: Which Method Detects Foot Strike in
           Rearfoot and Forefoot Runners Accurately when Using an Inertial
           Measurement Unit'

    • Authors: Christian Mitschke, Tobias Heß, Thomas Milani
      First page: 959
      Abstract: Accelerometers and gyroscopes are used to detect foot strike (FS), i.e., the moment when the foot first touches the ground. However, it is unclear whether different conditions (footwear hardness or foot strike pattern) influence the accuracy and precision of different FS detection methods when using such micro-electromechanical sensors (MEMS). This study compared the accuracy of four published MEMS-based FS detection methods with each other and the gold standard (force plate) to establish the most accurate method with regard to different foot strike patterns and footwear conditions. Twenty-three recreational runners (12 rearfoot and 11 forefoot strikers) ran on a 15-m indoor track at their individual running speed in three footwear conditions (low to high hardness). MEMS and a force plate were sampled at a rate of 3750 Hz. Individual accuracy and precision of FS detection methods were found which were dependent on running styles and footwear conditions. Most of the methods were characterized by a delay which generally increased from rearfoot to forefoot strike pattern and from high to low midsole hardness. It can be concluded that only one of the four methods can accurately determine FS in a variety of conditions.
      Citation: Applied Sciences
      PubDate: 2017-09-19
      DOI: 10.3390/app7090959
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 960: Antimony Oxide-Doped
           0.99Pb(Zr0.53Ti0.47)O3–0.01Bi(Y1−xSbx)O3 Piezoelectric Ceramics for
           Energy-Harvesting Applications

    • Authors: Iqbal Mahmud, Man-Soon Yoon, Soon-Chul Ur
      First page: 960
      Abstract: The effects of doping antimony oxides (Sb2O3/Sb2O5) on the ferroelectric/piezoelectric and energy-harvesting properties of 0.99Pb(Zr0.53Ti0.47)O3–0.01BiYO3 (PZT–BY) have been studied. The feasibility of doping Sb2O3 and Sb2O5 into the PZT–BY ceramics has also been compared by considering factors such as sintering condition, grain size, density, and electrical properties etc. This work discusses a detailed experimental observation using Sb2O3, because Sb2O5 is relatively expensive and does not follow the stoichiometric reaction mechanism when doped in PZT–BY. The Sb2O3-doped specimens were well sintered by oxygen-rich sintering and reached a maximum density of 99.1% of the theoretical value. X-ray diffraction (XRD) analysis showed a complete solid solution for all the specimens. Scanning electron microscope (SEM) observation revealed that the addition of Sb2O3 inhibits grain growth, and exhibits a denser and finer microstructure. The 0.1 moles of Sb2O3-doped ceramic shows a sharp decrease in the dielectric constant (ε33T = 690), while the piezoelectric charge constant (d33) and electromechanical coupling factor (kp) maintained high values of 350 pC/N and 66.0% respectively. The relatively higher value of d33 and lower ε33T of the 0.99Pb(Zr0.53Ti0.47)O3–0.01Bi(Y0.9Sb0.1)O3 ceramic resulted in an optimum value of piezoelectric voltage constant (g33 = 57.4 × 10−3 Vm/N) and a high figure of merit (d33 × g33 = 20075 × 10−15 m2/N). These values are high compared to recently reported works. Therefore, Sb2O3-doped PZT–BY ceramic could be a promising candidate material for the future study of power-harvesting devices.
      Citation: Applied Sciences
      PubDate: 2017-09-19
      DOI: 10.3390/app7090960
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 961: Application of Artificial Neural
           Networks to Ship Detection from X-Band Kompsat-5 Imagery

    • Authors: Jeong-In Hwang, Sung-Ho Chae, Daeseong Kim, Hyung-Sup Jung
      First page: 961
      Abstract: For ship detection, X-band synthetic aperture radar (SAR) imagery provides very useful data, in that ship targets look much brighter than surrounding sea clutter due to the corner-reflection effect. However, there are many phenomena which bring out false detection in the SAR image, such as noise of background, ghost phenomena, side-lobe effects and so on. Therefore, when ship-detection algorithms are carried out, we should consider these effects and mitigate them to acquire a better result. In this paper, we propose an efficient method to detect ship targets from X-band Kompsat-5 SAR imagery using the artificial neural network (ANN). The method produces the ship-probability map using ANN, and then detects ships from the ship-probability map by using a threshold value. For the purpose of getting an improved ship detection, we strived to produce optimal input layers used for ANN. In order to reduce phenomena related to the false detections, the non-local (NL)-means filter and median filter were utilized. The NL-means filter effectively reduced noise on SAR imagery without smoothing edges of the objects, and the median filter was used to remove ship targets in SAR imagery. Through the filtering approaches, we generated two input layers from a Kompsat-5 SAR image, and created a ship-probability map via ANN from the two input layers. When the threshold value of 0.67 was imposed on the ship-probability map, the result of ship detection from the ship-probability map was a 93.9% recall, 98.7% precision and 6.1% false alarm rate. Therefore, the proposed method was successfully applied to the ship detection from the Kompsat-5 SAR image.
      Citation: Applied Sciences
      PubDate: 2017-09-20
      DOI: 10.3390/app7090961
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 962: Editorial: Guided-Wave Optics

    • Authors: Boris Malomed
      First page: 962
      Abstract: Guided waves represent a vast class of phenomena in which the propagation of collective excitations in various media is steered in required directions by fixed (or, sometimes, reconfigurable) conduits [...]
      Citation: Applied Sciences
      PubDate: 2017-09-20
      DOI: 10.3390/app7090962
      Issue No: Vol. 7, No. 9 (2017)
       
  • Applied Sciences, Vol. 7, Pages 963: Indistinguishability Operators
           Applied to Task Allocation Problems in Multi-Agent Systems

    • Authors: José Guerrero, Juan-José Miñana, Oscar Valero, Gabriel Oliver
      First page: 963
      Abstract: In this paper we show an application of indistinguishability operators to model response functions. Such functions are used in the mathematical modeling of the task allocation problem in multi-agent systems when the stimulus, perceived by the agent, to perform a task is assessed by means of the response threshold model. In particular, we propose this kind of operators to represent a response function when the stimulus only depends on the distance between the agent and a determined task, since we prove that two celebrated response functions used in the literature can be reproduced by appropriate indistinguishability operators when the stimulus only depends on the distance to each task that must be carried out. Despite the fact there is currently no systematic method to generate response functions, this paper provides, for the first time, a theoretical foundation to generate them and study their properties. To validate the theoretical results, the aforementioned indistinguishability operators have been used to simulate, with MATLAB, the allocation of a set of tasks in a multi-robot system with fuzzy Markov chains.
      Citation: Applied Sciences
      PubDate: 2017-09-21
      DOI: 10.3390/app7100963
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 964: Bar-Wave Calibration of Acoustic
           Emission Sensors

    • Authors: Kanji Ono, Takahiro Hayashi, Hideo Cho
      First page: 964
      Abstract: This study extended a bar-wave calibration method for acoustic emission (AE) sensors. It combined laser interferometer displacement measurements and the wave propagation medium of a long bar, excited at its end with an ultrasonic transducer driven by a pulser. Receiving bar-wave sensitivities of 16 types of AE sensors were measured and compared to their receiving sensitivities to normally incident waves. The two types of the receiving sensitivity always differed for a given AE sensor. The bar-wave sensitivities of R6a sensors resembled their surface-wave sensitivities, indicating that the bar-wave sensitivities can represent the surface-wave sensitivities in typical AE applications. Some bar-wave modes were identified by comparing peaks found on observed Choi-Williams transform spectrograms with the positions on the dispersion curves for bar waves, calculated with the SAFE procedure. However, numerous bar-wave modes prevented exact identification, especially above 500 kHz. Aperture effects contributed to the sensitivity reduction at higher frequencies and to more fluctuating bar-wave receiving sensitivities even for sensors with smooth or flat receiving sensitivities to normally incident waves. Spectral dips observed in bar-wave results can be accounted for by aperture effect predictions reasonably well. For the selection of AE sensors, one needs to use the appropriate type of sensitivities considering waves to be detected.
      Citation: Applied Sciences
      PubDate: 2017-09-21
      DOI: 10.3390/app7100964
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 965: Registration of Urban Aerial Image
           and LiDAR Based on Line Vectors

    • Authors: Qinghong Sheng, Qi Wang, Xinyue Zhang, Bo Wang, Bin Zhang, Zhengning Zhang
      First page: 965
      Abstract: In a traditional registration of a single aerial image with airborne light detection and ranging (LiDAR) data using linear features that regard line direction as a control or linear features as constraints in the solution, lacking the constraint of linear position leads to the error propagation of the adjustment model. To solve this problem, this paper presents a line vector-based registration mode (LVR) in which image rays and LiDAR lines are expressed by a line vector that integrates the line direction and the line position. A registration equation of line vector is set up by coplanar imaging rays and corresponding control lines. Three types of datasets consisting of synthetic, theInternational Society for Photogrammetry and Remote Sensing (ISPRS) test project, and real aerial data are used. A group of progressive experiments is undertaken to evaluate the robustness of the LVR. Experimental results demonstrate that the integrated line direction and the line position contributes a great deal to the theoretical and real accuracies of the unknowns, as well as the stability of the adjustment model. This paper provides a new suggestion that, for a single image and LiDAR data, registration in urban areas can be accomplished by accommodating rich line features.
      Citation: Applied Sciences
      PubDate: 2017-09-21
      DOI: 10.3390/app7100965
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 966: A Hospital Recommendation System
           Based on Patient Satisfaction Survey

    • Authors: Mohammad Khoie, Tannaz Sattari Tabrizi, Elham khorasani, Shahram Rahimi, Nina Marhamati
      First page: 966
      Abstract: Surveys are used by hospitals to evaluate patient satisfaction and to improve general hospital operations. Collected satisfaction data is usually represented to the hospital administration by using statistical charts and graphs. Although such visualization is helpful, typically no deeper data analysis is performed to identify important factors which contribute to patient satisfaction. This work presents an unsupervised data-driven methodology for analyzing patient satisfaction survey data. The goal of the proposed exploratory data analysis is to identify patient communities with similar satisfaction levels and the major factors, which contribute to their satisfaction. This type of data analysis will help hospitals to pinpoint the prevalence of certain satisfaction factors in specific patient communities or clusters of individuals and to implement more proactive measures to improve patient experience and care. To this end, two layers of data analysis is performed. In the first layer, patients are clustered based on their responses to the survey questions. Each cluster is then labeled according to its salient features. In the second layer, the clusters of first layer are divided into sub-clusters based on patient demographic data. Associations are derived between the salient features of each cluster and its sub-clusters. Such associations are ranked and validated by using standard statistical tests. The associations derived by this methodology are turned into comments and recommendations for healthcare providers and patients. Having applied this method on patient and survey data of a hospital resulted in 19 recommendations where 10 of them were statistically significant with chi-square test’s p-value less than 0.5 and an odds ratio z-test’s p-value of more than 2 or less than −2. These associations not only are statistically significant but seems rational too.
      Citation: Applied Sciences
      PubDate: 2017-09-21
      DOI: 10.3390/app7100966
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 967: Computational and Experimental Study
           on Molecular Structure of Benzo[g]pyrimido[4,5-b]quinoline Derivatives:
           Preference of Linear over the Angular Isomer

    • Authors: Jorge Trilleras, Dency Pacheco, Alfredo Pérez-Gamboa, Jairo Quiroga, Alejandro Ortiz, Jaime Gálvez, Manuel Nogueras, Justo Cobo
      First page: 967
      Abstract: A series of 5-aryl-2-methylthio-5,12-dihydrobenzo[g]pyrimido[4,5-b]quinoline-4,6,11(3H)-trione was synthesized through an environmental friendly multicomponent methodology and characterized with FT-IR (Fourier Transform infrared spectroscopy), 1H NMR (Nuclear Magnetic Resonance ), 13C NMR and GC-MS (gas chromatography-mass spectrometry). The 5-(4-methoxyphenyl)-2-methylthio-5,12-dihydrobenzo[g]pyrimido[4,5-b]quinoline-4,6,11(3H)-trione 4c compound was characterized by X-ray single crystal diffraction. The geometry of 4c has been fully optimized using DFT (Density functional theory), B3LYP functional and 6-31G(d,p) basis set, thus establishing the ground state energy and thermodynamic features for the mentioned compound, which are in accordance with the experimental data and the crystal structure. The experimental results reveal a strong preference for the regioselective formation of 4c linear four fused rings over the angular four fused and suggest a possible kinetic control in product formation.
      Citation: Applied Sciences
      PubDate: 2017-09-21
      DOI: 10.3390/app7100967
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 968: Application of Deep Networks to Oil
           Spill Detection Using Polarimetric Synthetic Aperture Radar Images

    • Authors: Guandong Chen, Yu Li, Guangmin Sun, Yuanzhi Zhang
      First page: 968
      Abstract: Polarimetric synthetic aperture radar (SAR) remote sensing provides an outstanding tool in oil spill detection and classification, for its advantages in distinguishing mineral oil and biogenic lookalikes. Various features can be extracted from polarimetric SAR data. The large number and correlated nature of polarimetric SAR features make the selection and optimization of these features impact on the performance of oil spill classification algorithms. In this paper, deep learning algorithms such as the stacked autoencoder (SAE) and deep belief network (DBN) are applied to optimize the polarimetric feature sets and reduce the feature dimension through layer-wise unsupervised pre-training. An experiment was conducted on RADARSAT-2 quad-polarimetric SAR image acquired during the Norwegian oil-on-water exercise of 2011, in which verified mineral, emulsions, and biogenic slicks were analyzed. The results show that oil spill classification achieved by deep networks outperformed both support vector machine (SVM) and traditional artificial neural networks (ANN) with similar parameter settings, especially when the number of training data samples is limited.
      Citation: Applied Sciences
      PubDate: 2017-09-21
      DOI: 10.3390/app7100968
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 969: A Precise Positioning Method for a
           Puncture Robot Based on a PSO-Optimized BP Neural Network Algorithm

    • Authors: Guanwu Jiang, Minzhou Luo, Keqiang Bai, Saixuan Chen
      First page: 969
      Abstract: The problem of inverse kinematics is fundamental in robot control. Many traditional inverse kinematics solutions, such as geometry, iteration, and algebraic methods, are inadequate in high-speed solutions and accurate positioning. In recent years, the problem of robot inverse kinematics based on neural networks has received extensive attention, but its precision control is convenient and needs to be improved. This paper studies a particle swarm optimization (PSO) back propagation (BP) neural network algorithm to solve the inverse kinematics problem of a UR3 robot based on six degrees of freedom, overcoming some disadvantages of BP neural networks. The BP neural network improves the convergence precision, convergence speed, and generalization ability. The results show that the position error is solved by the research method with respect to the UR3 robot inverse kinematics with the joint angle less than 0.1 degrees and the output end tool less than 0.1 mm, achieving the required positioning for medical puncture surgery, which demands precise positioning of the robot to less than 1 mm. Aiming at the precise application of the puncturing robot, the preliminary experiment has been conducted and the preliminary results have been obtained, which lays the foundation for the popularization of the robot in the medical field.
      Citation: Applied Sciences
      PubDate: 2017-09-21
      DOI: 10.3390/app7100969
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 970: Supporting an Object-Oriented
           Approach to Unit Generator Development: The Csound Plugin Opcode Framework
           

    • Authors: Victor Lazzarini
      First page: 970
      Abstract: This article presents a new framework for unit generator development for Csound, supporting a full object-oriented programming approach. It introduces the concept of unit generators and opcodes, and its centrality with regards to music programming languages in general, and Csound in specific. The layout of an opcode from the perspective of the Csound C-language API is presented, with some outline code examples. This is followed by a discussion which places the unit generator within the object-oriented paradigm and the motivation for a full C++ programming support, which is provided by the Csound Plugin Opcode Framework (CPOF). The design of CPOF is then explored in detail, supported by several opcode examples. The article concludes by discussing two key applications of object-orientation and their respective instances in the Csound code base.
      Citation: Applied Sciences
      PubDate: 2017-09-21
      DOI: 10.3390/app7100970
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 971: A Comparison Study for
           Chloride-Binding Capacity between Alkali-Activated Fly Ash and Slag in the
           Use of Seawater

    • Authors: Yubin Jun, Seyoon Yoon, Jae Oh
      First page: 971
      Abstract: This study aimed to investigate the chloride-binding capacity of alkali-activated fly ash (denoted as FSW) and slag (denoted as SSW) samples and their synthesized Cl-bearing phases, which are capable of binding and immobilizing chloride when seawater is used as the mixing water. This study also examined the progressive changes in the pore structures of the FSW and SSW samples over time. The results show that the SSW sample is significantly more effective in the uptake of chloride ions compared to the FSW sample at 28 days of curing. While the FSW sample forms Cl-bearing zeolites (Cl-chabazite and Cl-sodalite) (possibly with similar types of geopolymeric gels), the SSW sample synthesizes Cl-bearing, layered double hydroxides (LDH) (Cl-hydrocalumite and Cl-hydrotalcite). Although both samples involve Cl-binding phases, the FSW sample is likely to be less efficient because it largely produces zeolites (or similar geopolymeric gels) with no Cl-binding capability (i.e., zeolites X and Y). Meanwhile, the SSW sample produces Cl-bearing LDH phases as well as C-S-H(I), which can physically adsorb chloride. The SSW sample exhibits both pore-size refinement and porosity reduction over time, while the FSW sample only exhibits pore-size refinement. Therefore, the SSW system is more advantageous in the use of seawater because it more effectively prevents Cl ingression due to greater impermeability.
      Citation: Applied Sciences
      PubDate: 2017-09-22
      DOI: 10.3390/app7100971
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 972: Enhanced Design of a Soft Thin-Film
           Vibrotactile Actuator Based on PVC Gel

    • Authors: Won-Hyeong Park, Eun-Jae Shin, Sang-Youn Kim
      First page: 972
      Abstract: We fabricated a soft thin-film vibrotactile actuator, which can be easily inserted into wearable devices, based on an electroactive PVC gel. One of the most important factors in fabricating a soft and thin vibrotactile actuator is to create vibrational force strong enough to stimulate human skin in a wide frequency range. To achieve this, we investigate the working principle of the PVC gel and suggest a new structure in which most of electric energy contributes to the deformation of the PVC gel. Due to this structure, the vibrational amplitude of the proposed PVC gel actuator could considerably increase (0.816 g (g = 9.8 m/s2) at resonant frequency). The vibrotactile amplitude is proportional to the amount of input voltage. It increased from 0.05 g up to 0.416 g with increasing applied voltages from 200 V to 1 kV at 1 Hz. The experimental results show that the proposed actuator can create a variety of haptic sensations.
      Citation: Applied Sciences
      PubDate: 2017-09-22
      DOI: 10.3390/app7100972
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 973: A Review of Three-Dimensional
           Scanning Near-Field Optical Microscopy (3D-SNOM) and Its Applications in
           Nanoscale Light Management

    • Authors: Paul Bazylewski, Sabastine Ezugwu, Giovanni Fanchini
      First page: 973
      Abstract: In this article, we present an overview of aperture and apertureless type scanning near-field optical microscopy (SNOM) techniques that have been developed, with a focus on three-dimensional (3D) SNOM methods. 3D SNOM has been undertaken to image the local distribution (within ~100 nm of the surface) of the electromagnetic radiation scattered by random and deterministic arrays of metal nanostructures or photonic crystal waveguides. Individual metal nanoparticles and metal nanoparticle arrays exhibit unique effects under light illumination, including plasmon resonance and waveguiding properties, which can be directly investigated using 3D-SNOM. In the second part of this article, we will review a few applications in which 3D-SNOM has proven to be useful for designing and understanding specific nano-optoelectronic structures. Examples include the analysis of the nano-optical response phonetic crystal waveguides, aperture antennae and metal nanoparticle arrays, as well as the design of plasmonic solar cells incorporating random arrays of copper nanoparticles as an optical absorption enhancement layer, and the use of 3D-SNOM to probe multiple components of the electric and magnetic near-fields without requiring specially designed probe tips. A common denominator of these examples is the added value provided by 3D-SNOM in predicting the properties-performance relationship of nanostructured systems.
      Citation: Applied Sciences
      PubDate: 2017-09-22
      DOI: 10.3390/app7100973
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 974: Multivariate Analysis of
           Laser-Induced Tissue Ablation: Ex Vivo Liver Testing

    • Authors: Suhyun Park, Hyun Kang
      First page: 974
      Abstract: A number of laser parameters are often regulated to enhance ablation efficiency during laser surgery. As one of clinical treatments, laser removal of benign prostate hyperplasia has been well accepted by surgical urologists. However, due to complex interactions of the surgical parameters, the procedure is still lengthy and dependent upon the surgeon’s skill and experience. The aim of the current study is to evaluate the feasibility of response surface method (RSM) to comprehend ablative interactions of multi-parameters and to identify the optimal ablation rate (AR). As a surrogate model in the feasibility study, bovine liver tissue was utilized for ex vivo ablation testing. Three laser parameters pertinent to laser prostatectomy were selected: power (P), treatment speed (TS), and beam spot (BS). As a three-level fractional factorial RSM, Box Behnken design (BBD) was employed to identify the range of each parameter for achieving the optimal AR. The results showed that regardless of TS, AR was linearly contingent on both P and BS due to high irradiance. TS of 6~7 mm/s induced the maximal AR when P of 180 W and BS of 0.4 mm2. The corresponding volumetric density energy yielded an ablation volume of 80 mm2, which was close to a transition to volumetric saturation. The BBD-based model showed a good agreement with the experimental data in terms of ablation volume. The proposed multivariate parametric analysis can be an efficient design method to identify the optimal conditions for laser therapeutics. Further investigations will be performed on prostatic tissue to validate the proposed approach and to explore various optimization processes.
      Citation: Applied Sciences
      PubDate: 2017-09-22
      DOI: 10.3390/app7100974
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 975: Assessing the Performance of Thermal
           Inertia and Hydrus Models to Estimate Surface Soil Water Content

    • Authors: Amro Negm, Fulvio Capodici, Giuseppe Ciraolo, Antonino Maltese, Giuseppe Provenzano, Giovanni Rallo
      First page: 975
      Abstract: The knowledge of soil water content (SWC) dynamics in the upper soil layer is important for several hydrological processes. Due to the difficulty of assessing the spatial and temporal SWC dynamics in the field, some model-based approaches have been proposed during the last decade. The main objective of this work was to assess the performance of two approaches to estimate SWC in the upper soil layer under field conditions: the physically-based thermal inertia and the Hydrus model. Their validity was firstly assessed under controlled laboratory conditions. Thermal inertia was firstly validated in laboratory conditions using the transient line heat source (TLHS) method. Then, it was applied in situ to analyze the dynamics of soil thermal properties under two extreme conditions of soil-water status (well-watered and air-dry), using proximity remote-sensed data. The model performance was assessed using sensor-based measurements of soil water content acquired through frequency (FDR) and time domain reflectometry (TDR). During the laboratory experiment, the Root Mean Square Error (RMSE) was 0.02 m3 m−3 for the Hydrus model and 0.05 m3 m−3 for the TLHS model approach. On the other hand, during the in situ experiment, the temporal variability of SWCs simulated by the Hydrus model and the corresponding values measured by the TDR method evidenced good agreement (RMSE ranging between 0.01 and 0.005 m3 m−3). Similarly, the average of the SWCs derived from the thermal diffusion model was fairly close to those estimated by Hydrus (spatially averaged RMSE ranging between 0.03 and 0.02 m3 m−3).
      Citation: Applied Sciences
      PubDate: 2017-09-22
      DOI: 10.3390/app7100975
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 976: New Chaotic Dynamical System with a
           Conic-Shaped Equilibrium Located on the Plane Structure

    • Authors: Jiri Petrzela, Tomas Gotthans
      First page: 976
      Abstract: This paper presents a new autonomous deterministic dynamical system with equilibrium degenerated into a plane-oriented hyperbolic geometrical structure. It is demonstrated via numerical analysis and laboratory experiments that the discovered system has both a structurally stable strange attractor and experimentally measurable chaotic behavior. It is shown that the evolution of complex dynamics can be associated with a single parameter of a mathematical model and, due to one-to-one correspondence, to a single circuit parameter. Two-dimensional high resolution plots of the largest Lyapunov exponent and basins of attraction expressed in terms of final state energy are calculated and put into the context of the discovered third-order mathematical model and real chaotic oscillator. Both voltage- and current-mode analog chaotic oscillators are presented and verified by visualization of the typical chaotic attractor in a different fashion.
      Citation: Applied Sciences
      PubDate: 2017-09-22
      DOI: 10.3390/app7100976
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 977: Film Thickness Estimation for the Oil
           Applied to the Inner Surface of Slim Tubes

    • Authors: Jozef Svetlík, Ján Buša, Tomáš Brestovič, Jozef Dobránsky, Ján Kráľ
      First page: 977
      Abstract: The article deals with the approximation of the results of experimental measurement of coating of the inner surface of slim pipes with special oil, using a dispersion oil fraction. The reason for such treatment of the inner surface of the tubes is the anti-corrosion protection or various other requirements. The oil manufacturer prescribes the minimum required layer to guarantee the anti-corrosion protection parameters. Therefore, it is advisable to know the most exact coating parameters for different pipe diameters. The measured results give us an assumption of how much oil is sufficient to coat the inside of a pipe. The main idea lies in the correct estimation of coefficients in the three-parameter exponential dependence. For the initial estimates, Nelder–Mead’s minimization method was used. The condition for meeting the lower estimate of the minimum thickness of the oil layer was determined. Following graphic processing of minimization of individual pipe diameters, in some cases, the coefficients were adjusted manually. The result is that the oil thickness depends on the distance of the investigated point from the beginning of the tube, or on the point of entry of the dispersion oil fraction.
      Citation: Applied Sciences
      PubDate: 2017-09-22
      DOI: 10.3390/app7100977
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 978: CEPP: Perceiving the Emotional State
           of the User Based on Body Posture

    • Authors: Suk Lee, Mungyu Bae, Woonghee Lee, Hwangnam Kim
      First page: 978
      Abstract: Much research has been conducted in the area of face and gesture recognition in order to classify one’s emotional state. Surprisingly, utilizing computerized algorithms which recognize emotional conditions based on body postures has not yet been systematically developed. In this paper, we propose a novel method, Computerized Emotion Perception based on Posture (CEPP), to determine the emotional state of the user. This method extracts features from body postures and estimates the emotional state by computing a similarity distance. With the proposed algorithm, we will provide new insights into automatically recognizing one’s emotional state.
      Citation: Applied Sciences
      PubDate: 2017-09-22
      DOI: 10.3390/app7100978
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 979: 3D-Printed Super-Wideband Spidron
           Fractal Cube Antenna with Laminated Copper

    • Authors: Oh Kwon, Won Park, Sungwoo Lee, Jong Lee, Young Park, Keum Hwang
      First page: 979
      Abstract: In this paper, a 3D-printed super-wideband (SWB) Spidron fractal cube antenna is proposed. The Spidron fractal configuration is utilized as a self-complementary structure on each face of a 3D frame to attain SWB characteristics. The antenna is excited through a tapered microstrip balun for both mode transforming and impedance matching. A prototype of the proposed antenna, including the 3D frame fabricated with the help of a 3D printer and Spidron fractal patches made of copper tape, is experimentally verified. The measured −10 dB reflection ratio bandwidth is 34:1 (0.44–15.38 GHz). The peak gain varies from 3.42 to 9.29 dBi within the operating frequency bandwidth. The measured radiation patterns are nearly omnidirectional at all operating frequency bands.
      Citation: Applied Sciences
      PubDate: 2017-09-22
      DOI: 10.3390/app7100979
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 980: Postharvest Behavior of Bioactive
           Compounds in Tomato Fruits Treated with Cu Nanoparticles and NaCl Stress

    • Authors: Alma Hernández-Fuentes, Esly López-Vargas, José Pinedo-Espinoza, Rafael Campos-Montiel, Jesús Valdés-Reyna, Antonio Juárez-Maldonado
      First page: 980
      Abstract: Tomatoes are important for human diet due to their content of bioactive compounds. However, is little known about behavior of these compounds during fruit shelf life. The goal of this research was to evaluate the effects on bioactive compounds of tomato fruits stored during different times and conditions, obtained from tomato plants developed under conditions of saline stress and with the application of copper nanoparticles. Four treatments were evaluated: foliar spray of copper nanoparticles (250 mg L−1) with or without saline stress, only saline stress, and the absolute control. The results show that application of copper nanoparticles has a positive effect on the accumulation of bioactive compounds such as total phenols, β-carotene, and vitamin C. The saline stress during the development of tomato plants causes a decrease of the bioactive compounds as well as antioxidant capacity in tomato fruits. However, this negative effect can be reduced with the application of copper nanoparticles. The application of copper nanoparticles may be a technique to increase and maintain the content of bioactive compounds in tomato fruits and can be an effective alternative to diminish the negative effects on bioactive compounds caused by saline stress.
      Citation: Applied Sciences
      PubDate: 2017-09-23
      DOI: 10.3390/app7100980
      Issue No: Vol. 7, No. 10 (2017)
       
  • Applied Sciences, Vol. 7, Pages 982: Residual Stress and Deformation
           Analysis in Butt Welding on 6 mm SUS304 Steel with Jig Constraints Using
           Gas Metal Arc Welding

    • Authors: Chi-Liang Kung, Cheng-Kuang Hung, Chao-Ming Hsu, Cheng-Yi Chen
      First page: 982
      Abstract: This article proposes a novel method for analyzing residual stress and deformation in butt welding on 6 mm SUS304 stainless steel plates, using MSC.MARC, a commercial finite element method software, to find the best location for jig fixtures that will minimize welding deformation. Simulation and experimental studies show that a distance of 100 mm between the jig center and the welding bead center is best for inhibiting welding deformation when the jigs experience downward displacement at 0 mm on the steel plate; the total displacement is only about 1.1 mm in the case of a 300 × 250 × 6 mm SUS304 steel plate. In addition, a numerical model shows that four jigs with pitches of 200 mm can better reduce welding deformation than six jigs with pitches of 100 mm. The largest residual stress after welding occurs around the weld bead center, and the residual stress away from the welding bead center increases gradually when jigs have been applied on the steel plate to prevent deformation. The reaction force of the jigs on the steel plate has no further effect in reducing deformation. We conclude that commercially available jigs can inhibit deformation during the welding process.
      Citation: Applied Sciences
      PubDate: 2017-09-23
      DOI: 10.3390/app7100982
      Issue No: Vol. 7, No. 10 (2017)
       
 
 
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