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  • 1
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    Reaction Mechanism and Kinetics for Hydrolytic Dehydrogenation of Ammonia Borane on a Pt/CNT Catalyst (2016)
    Wiley-Blackwell
    Details
    Publication Date: 2016-06-26
    Description: A reaction mechanism is proposed for hydrolytic dehydrogenation of ammonia borane on a Pt/CNT catalyst. A combination of thermodynamic analysis and FTIR measurement reveals that B-containing byproducts are mainly in the form of an NH 4 B(OH) 4 -B(OH) 3 mixture rather than NH 4 BO 2 reported previously. The revised main reaction is NH 3 BH 3 +4H 2 O NH 4 + +B(OH) 4 - +3H 2 , involving the B-H, B-N and O-H bond cleavages. Isotopic experiments using D 2 O instead of H 2 O as reactant or introducing D 2 into the reaction atmosphere suggest the O-H bond cleavage being in the rate-determining step, and an unfavorable occurrence of the chemisorbed H 2 O dissociation (i.e., the direct O-H bond cleavage), respectively. Different reaction pathways with indirect O-H bond cleavages are analyzed, and then NH 3 BH 2 *+H 2 O* NH 3 BH 2 (OH)*+H* is suggested as the rate-determining step. Subsequently, a Langmuir-Hinshelwood kinetic model is developed, which fits well with the experimental data. This article is protected by copyright. All rights reserved.
    Print ISSN: 0001-1541
    Electronic ISSN: 1547-5905
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Published by Wiley-Blackwell on behalf of The American Institute of Chemical Engineers (AIChE).
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  • 2
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    Sensors, Vol. 16, Pages 1683: Decomposition of Composite Electric Field in a Three-Phase D-Dot Voltage Transducer Measuring System (2016)
    MDPI Publishing
    In: Sensors
    Details
    Publication Date: 2016-10-13
    Description: In line with the wider application of non-contact voltage transducers in the engineering field, transducers are required to have better performance for different measuring environments. In the present study, the D-dot voltage transducer is further improved based on previous research in order to meet the requirements for long-distance measurement of electric transmission lines. When measuring three-phase electric transmission lines, problems such as synchronous data collection and composite electric field need to be resolved. A decomposition method is proposed with respect to the superimposed electric field generated between neighboring phases. The charge simulation method is utilized to deduce the decomposition equation of the composite electric field and the validity of the proposed method is verified by simulation calculation software. With the deduced equation as the algorithm foundation, this paper improves hardware circuits, establishes a measuring system and constructs an experimental platform for examination. Under experimental conditions, a 10 kV electric transmission line was tested for steady-state errors, and the measuring results of the transducer and the high-voltage detection head were compared. Ansoft Maxwell Stimulation Software was adopted to obtain the electric field intensity in different positions under transmission lines; its values and the measuring values of the transducer were also compared. Experimental results show that the three-phase transducer is characterized by a relatively good synchronization for data measurement, measuring results with high precision, and an error ratio within a prescribed limit. Therefore, the proposed three-phase transducer can be broadly applied and popularized in the engineering field.
    Electronic ISSN: 1424-8220
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Published by MDPI Publishing
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  • 3
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    Energies, Vol. 11, Pages 545: Thermal Rating of Offshore Wind Farm Cables Installed in Ventilated J-Tubes (2018)
    MDPI Publishing
    In: Energies
    Details
    Publication Date: 2018-03-06
    Description: Energies, Vol. 11, Pages 545: Thermal Rating of Offshore Wind Farm Cables Installed in Ventilated J-Tubes Energies doi: 10.3390/en11030545 Authors: Lei You Jian Wang Gang Liu Hui Ma Ming Zheng The section of submarine cable that is installed in enclosed J-tubes represents a possible thermal limiting point along the export circuits of offshore wind farms (OWFs). To obtain higher continuous thermal ratings for J-tube systems, a ventilated design, realized by allowing for the flow of natural wind into the J-tube through vents, is considered in this paper. To evaluate the performance of this forced-ventilation design, a coupled three-dimensional (3D) numerical model is constructed using the computational fluid dynamics (CFD) technique. The CFD method is first successfully tested through comparisons with existing methods for enclosed J-tubes. Then, the cable rating for the ventilated design is determined using the CFD model and compared with the rating for the enclosed case. The results show that the cooling effect from forced ventilation is obvious, and the cable rating could be increased by up to 27.5% for a wind speed of 10 m/s. This improvement in rating is especially significant for OWFs where the export circuit output is limited by the cable rating in enclosed J-tubes.
    Electronic ISSN: 1996-1073
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by MDPI Publishing
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  • 4
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    IJGI, Vol. 7, Pages 193: Implementation of a Parallel GPU-Based Space-Time Kriging Framework (2018)
    MDPI Publishing
    Details
    Publication Date: 2018-05-18
    Description: IJGI, Vol. 7, Pages 193: Implementation of a Parallel GPU-Based Space-Time Kriging Framework ISPRS International Journal of Geo-Information doi: 10.3390/ijgi7050193 Authors: Yueheng Zhang Xinqi Zheng Zhenhua Wang Gang Ai Qing Huang In the study of spatiotemporal geographical phenomena, the space–time interpolation method is widely applied, and the demands for computing speed and accuracy are increasing. For nonprofessional modelers, utilizing the space–time interpolation method quickly is a challenge. To solve this problem, the classical ordinary kriging algorithm was selected and expanded to a spatiotemporal kriging algorithm. Using the OpenCL framework to integrate central processing unit (CPU) and graphic processing unit (GPU) computing resources, a parallel spatiotemporal kriging algorithm was implemented, and three experiments were conducted in this work to verify the results. The results indicated the following: (1) when the size of the prediction point dataset is consistent, the performance of the method is robust with the increasing size of the observation point dataset; (2) the acceleration effect of the parallel method increases with an increased number of predicted points. Compared with the original sequential program, the implementation of the improved parallel framework showed a 3.23 speedup, which obviously shortens the interpolation time; (3) when cross-validating the temperature data in the Beijing Tianjin Hebei region, the space–time acceleration model provides a better fit than traditional pure space interpolation.
    Electronic ISSN: 2220-9964
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Published by MDPI Publishing on behalf of International Society for Photogrammetry and Remote Sensing (ISPRS).
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  • 5
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    Sensors, Vol. 17, Pages 1558: Direct Quantification of Cd2+ in the Presence of Cu2+ by a Combination of Anodic Stripping Voltammetry Using a Bi-Film-Modified Glassy Carbon Electrode and an Artificial Neural Network (2017)
    MDPI Publishing
    In: Sensors
    Details
    Publication Date: 2017-07-04
    Description: : In this study, a novel method based on a Bi/glassy carbon electrode (Bi/GCE) for quantitatively and directly detecting Cd2+ in the presence of Cu2+ without further electrode modifications by combining square-wave anodic stripping voltammetry (SWASV) and a back-propagation artificial neural network (BP-ANN) has been proposed. The influence of the Cu2+ concentration on the stripping response to Cd2+ was studied. In addition, the effect of the ferrocyanide concentration on the SWASV detection of Cd2+ in the presence of Cu2+ was investigated. A BP-ANN with two inputs and one output was used to establish the nonlinear relationship between the concentration of Cd2+ and the stripping peak currents of Cu2+ and Cd2+. The factors affecting the SWASV detection of Cd2+ and the key parameters of the BP-ANN were optimized. Moreover, the direct calibration model (i.e., adding 0.1 mM ferrocyanide before detection), the BP-ANN model and other prediction models were compared to verify the prediction performance of these models in terms of their mean absolute errors (MAEs), root mean square errors (RMSEs) and correlation coefficients. The BP-ANN model exhibited higher prediction accuracy than the direct calibration model and the other prediction models. Finally, the proposed method was used to detect Cd2+ in soil samples with satisfactory results.
    Electronic ISSN: 1424-8220
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Published by MDPI Publishing
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  • 6
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    Sensors, Vol. 12, Pages 12424-12436: A Nonlinear Adaptive Beamforming Algorithm Based on Least Squares Support Vector Regression (2012)
    MDPI Publishing
    In: Sensors
    Details
    Publication Date: 2012-09-13
    Description: To overcome the performance degradation in the presence of steering vector mismatches, strict restrictions on the number of available snapshots, and numerous interferences, a novel beamforming approach based on nonlinear least-square support vector regression machine (LS-SVR) is derived in this paper. In this approach, the conventional linearly constrained minimum variance cost function used by minimum variance distortionless response (MVDR) beamformer is replaced by a squared-loss function to increase robustness in complex scenarios and provide additional control over the sidelobe level. Gaussian kernels are also used to obtain better generalization capacity. This novel approach has two highlights, one is a recursive regression procedure to estimate the weight vectors on real-time, the other is a sparse model with novelty criterion to reduce the final size of the beamformer. The analysis and simulation tests show that the proposed approach offers better noise suppression capability and achieve near optimal signal-to-interference-and-noise ratio (SINR) with a low computational burden, as compared to other recently proposed robust beamforming techniques.
    Electronic ISSN: 1424-8220
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Published by MDPI Publishing
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  • 7
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    Sensors, Vol. 17, Pages 2611: Integrated Display and Simulation for Automatic Dependent Surveillance–Broadcast and Traffic Collision Avoidance System Data Fusion (2017)
    MDPI Publishing
    In: Sensors
    Details
    Publication Date: 2017-11-16
    Description: Sensors, Vol. 17, Pages 2611: Integrated Display and Simulation for Automatic Dependent Surveillance–Broadcast and Traffic Collision Avoidance System Data Fusion Sensors doi: 10.3390/s17112611 Authors: Yanran Wang Gang Xiao Zhouyun Dai Automatic Dependent Surveillance–Broadcast (ADS-B) is the direction of airspace surveillance development. Research analyzing the benefits of Traffic Collision Avoidance System (TCAS) and ADS-B data fusion is almost absent. The paper proposes an ADS-B minimum system from ADS-B In and ADS-B Out. In ADS-B In, a fusion model with a variable sampling Variational Bayesian-Interacting Multiple Model (VSVB-IMM) algorithm is proposed for integrated display and an airspace traffic situation display is developed by using ADS-B information. ADS-B Out includes ADS-B Out transmission based on a simulator platform and an Unmanned Aerial Vehicle (UAV) platform. This paper describes the overall implementation of ADS-B minimum system, including theoretical model design, experimental simulation verification, engineering implementation, results analysis, etc. Simulation and implementation results show that the fused system has better performance than each independent subsystem and it can work well in engineering applications.
    Electronic ISSN: 1424-8220
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Published by MDPI Publishing
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  • 8
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    Upregulation of Klotho Potentially Inhibits Pulmonary Vascular Remodeling by Blocking the Activation of the Wnt Signaling Pathway in Rats with PM2.5-Induced Pulmonary Arterial Hypertension (2018)
    Wiley-Blackwell
    Details
    Publication Date: 2018-01-31
    Description: ABSTRACT We evaluated the effects of Klotho on pulmonary vascular remodeling and cell proliferation and apoptosis in rat models with PM2.5-induced pulmonary arterial hypertension (PAH) via the Wnt signaling pathway. After establishing rat models of PM2.5-induced PAH, these Sprague-Dawley male rats were randomized into control and model groups. Cells extracted from the model rats were sub-categorized into different groups. Activation of Wnt/β-catenin signaling transcription factor was detected by a TOPFlash/FOPFlash assay. A serial of experiment was conducted to identify the mechanism of Klotho on PHA via the Wnt signaling pathway. VEGF levels and PaCO 2 content were higher in the model group, while PaO 2, NO 2 - /NO 3 - content and Klotho level was lower compared to the control group. In comparison to the control group, the model group had decreased Klotho and Bax levels, and elevated Wnt-1, β-catenin, bcl-2, survivin and PCNA expression, VEGF, IL-6, TNF-α, TNF-β1 and bFGF levels, as well as the percentage of pulmonary artery ring contraction. The Klotho vector, DKK-1 and DKK-1 + Klotho vector groups exhibited reduced cell proliferation, luciferase activity, and the expression of Wnt-1, β-catenin, bcl-2, survivin and PCNA, as well as shortened S phase compared with the blank and NC groups. Compared with the Klotho vector and DKK-1 groups, the DKK-1 + Klotho vector groups had reduced cell proliferation, luciferase activity, and the expression of Wnt-1, β-catenin, bcl-2, survivin and PCNA, as well as a shortened S phase. Conclusively, Klotho inhibits pulmonary vascular remodeling by inactivation of Wnt signaling pathway. This article is protected by copyright. All rights reserved
    Electronic ISSN: 0091-7419
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Published by Wiley-Blackwell
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  • 9
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    Energies, Vol. 10, Pages 1541: Techniques for Reduction of the Cogging Torque in Claw Pole Machines with SMC Cores (2017)
    MDPI Publishing
    In: Energies
    Details
    Publication Date: 2017-10-07
    Description: Energies, Vol. 10, Pages 1541: Techniques for Reduction of the Cogging Torque in Claw Pole Machines with SMC Cores Energies doi: 10.3390/en10101541 Authors: Chengcheng Liu Jiawei Lu Youhua Wang Gang Lei Jianguo Zhu Youguang Guo As one of the main parasitic parameters in permanent magnet (PM) synchronous machines (PMSMs), cogging torque is the main component of the torque ripple, which has always been the handicap in the high-performance, low-speed drive systems. Over the last two decades, various methods have been proposed to decrease the cogging torque in both radial-flux and axial-flux PMSMs. Among these methods, stator slot skewing, stator tooth notching, permanent magnet (PM) skewing, PM shifting, and pole pairing are extensively investigated. However, little work has been done on reducing the cogging torque of the claw pole machine (CPM), whose cogging torque cannot be ignored. In this paper, the general methods that have been used to reduce the cogging torque in radial-flux and axial-flux PMSMs are developed and verified in a CPM with a soft magnetic composite (SMC) core. The 3-D finite element method (FEM) is used to calculate the cogging torque and PM flux linkage per turn. By comparing different cogging torque reduction technologies, it can be found that the magnet step skewing and unequal claw pole width are very suitable for CPM.
    Electronic ISSN: 1996-1073
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by MDPI Publishing
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  • 10
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    Energies, Vol. 11, Pages 1998: Design Issues for Claw Pole Machines with Soft Magnetic Composite Cores (2018)
    MDPI Publishing
    In: Energies
    Details
    Publication Date: 2018-08-02
    Description: Energies, Vol. 11, Pages 1998: Design Issues for Claw Pole Machines with Soft Magnetic Composite Cores Energies doi: 10.3390/en11081998 Authors: Chengcheng Liu Jiawei Lu Youhua Wang Gang Lei Jianguo Zhu Youguang Guo By using global ring winding, the torque coefficient of the transverse flux machine (TFM) is proportional to its number of pole pairs, and thus the TFM possesses high torque density ability when compared with other electrical machines. As a special kind of TFM, the claw pole machine (CPM) can have more torque due to its special claw pole teeth. The manufacturing of CPM or TFM with silicon steels was very difficult in the past, and is a handicap for the progress of this kind of machine. Thanks to the advent of soft magnetic composite (SMC) materials, the manufacturing process of CPM has become more and more simple. More attention has been paid to this kind of technology, and some mass production CPMs with SMC cores have appeared. However, there are few works that discuss the key design issues for this kind of machine. In this paper, a small CPM with SMC is used as as a research benchmark. Various design methods that can be adopted to improve its performance have been studied, including unequal stator claw pole teeth, a skewing magnet design, consequent pole design, and etc. The 3D finite element method (FEM) is used for the machine analysis, and it is verified by the experimental results of a CPM with SMC cores.
    Electronic ISSN: 1996-1073
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by MDPI Publishing
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