bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non‐isolated DC–DC converter with cubic voltage gain and ripple‐free input current
Authors: Samuel Vijay Joseph , Keerthi Gna , Mahalingam Prabhakar 
Published: September 2020

In this study, a non‐isolated high gain DC–DC converter is presented. The proposed converter yields a voltage conversion ratio value which is a cubic function of the voltage gain obtained from a boost converter. The proposed converter is synthesised by judiciously interfacing a two‐phase interleaved boost converter with voltage‐lift capacitor and a quadratic boost converter. Resultantly, the proposed converter yields a practical voltage gain of 21.11. Further, due to the use of interleaving technique, the input current is completely free from ripples. The proposed concept is validated by conducting experiments on 18/380 V, 160 W prototype converter. The experimental results clearly demonstrate that the proposed converter operates at a full‐load efficiency of 95.6%. Further, by practically implementing a simple closed‐loop control, the output voltage of the converter is quickly regulated against variations in input voltage and load current so as to provide the desired 380 V across the load terminals.
Development of grid‐interactive inverter utilising induction motor driven photovoltaic water pumping system
Authors: Vamja Rajan V. , Mulla Mahmadasraf A. 
Published: September 2020

The stand‐alone solar photovoltaic water pumping system (SPVWPS) remains idle for a significant period of time, when irrigation is not required and when sun is not available. Due to this large idle period, the effective utilisation of SPVWPS assets, i.e. solar photovoltaic array, power electronics converter, and motor, is poor. This study presents an approach to increase the effective utilisation of SPVWPS under the aforementioned idle period. It is proposed to interface the grid with SPVWPS without adding extra power electronic interface. An innovative integrated photovoltaic inverter is constructed using existing SPVWPS components. The inverter enables the transfer of active power and exchange of reactive power with the grid during an idle period of SPVWPS. The three legs of the voltage source inverter (VSI) are interleaved with motor windings. The VSI switches are controlled with synchronous pulse width modulation to force a cophasal current in the motor windings. This accompanies a net motor torque to zero under grid‐interactive operation. Hence, the three‐phase VSI operates as a single‐phase grid synchronise converter, and the motor windings are used as filter inductance. The control system is presented to establish grid‐interactive functionality. A prototype is developed to verify system performance. The control system is implemented using the ARM Cortex‐M4 microcontroller.
Interleaved high step‐up ZVS DC–DC converter with coupled inductor and built‐in transformer for renewable energy systems applications
Authors: Nouri Tohid , Shaneh Mahdi , Ghorbani Alireza 
Published: September 2020

A zero voltage switching (ZVS) interleaved high step‐up converter with coupled inductor and built‐in transformer voltage multiplier cell is introduced in this study. A more flexible design is provided by increasing the voltage conversion ratio by utilising the turns ratios of the coupled inductor and built‐in transformer. The ZVS operation of the metal‐oxide‐semiconductor field‐effect transistors (MOSFETs) and absorption of the leakage current are realised through active clamp circuits. Furthermore, the voltage stress across the switching devices is minimised that give rises to implementation of low voltage rated MOSFETs and consequently low conduction losses. Meanwhile, the diode reverse current problem is alleviated by the leakage inductance of the coupled inductor and built‐in transformer. All of the abovementioned advantages make the proposed converter as a high efficiency candidate for high current and high step‐up applications. Finally, a 600 W, 48–700 V voltage conversion with the conversion efficiency of 97% is fabricated to probe the merits of the proposed converter.
Synthesis of flower‐like and hexagonal flake‐like ZnO using microwave method and their photocatalytic activity
Authors: Si Wei , Pei Liran 
Published: September 2020

The flower‐like and hexagonal flake‐like ZnO microstructures were synthesised by a microwave method using ammonia water and sodium hydroxide as precipitant, respectively. The products were characterised by scanning electron microscopy, high‐resolution transmission electron microscopy, X‐ray diffraction and photoluminescence. The photocatalytic activity of the flower‐like and hexagonal flake‐like ZnO microstructures was evaluated by the degradation of methyl orange (MO) under ultraviolet (UV) light irradiation. The results indicated that the best flower‐like ZnO microstructure was obtained when the experimental conditions were [Zn2+] = 0.025 mol l−1, [Zn2+]:[NH3·H2O] = 1:1.5, microwave power = 231 W. Under the same reaction conditions, hexagonal flake‐like ZnO can be obtained by using sodium hydroxide as precipitant. The MO in aqueous solution was completely eliminated by flower‐like ZnO after 120 min of UV light irradiation. Under identical conditions, the degradation of MO in aqueous solution was completely finished within 150 min in the presence of hexagonal flake‐like ZnO. The flower‐like ZnO sample showed an enhanced photocatalytic activity compared with the hexagonal flake‐like ZnO for the MO degradation, which could be attributed to the presence of more active centres and hence can have more opportunities to contact with MO molecules.
The POLAR gamma-ray burst polarization catalog
Authors: Kole M. , De Angelis N. , Berlato F. , Burgess J. M. , Gauvin N. , Greiner J. , Hajdas W. , Li H. C. , Li Z. H. , Pollo A. , Produit N. , Rybka D. , Song L. M. , Sun J. C. , Szabelski J. , Tymieniecka T. , Wang Y. H. , Wu B. B. , Wu X. , Xiong S. L. , Zhang S. N. , Zhang Y. J. 
Published: September 2020

Context.Despite over 50 years of research, many open questions remain about the origin and nature of gamma-ray bursts (GRBs). Linear polarization measurements of the prompt emission of these extreme phenomena have long been thought to be key to answering a range of these questions. The POLAR detector was designed to produce the first set of detailed and reliable linear polarization measurements in the 50 − 500 keV energy range. During late 2016 and early 2017, POLAR detected a total of 55 GRBs. The analysis results of 5 of these GRBs have been reported, and were found to be consistent with a low or unpolarized flux. However, previous reports by other collaborations found high levels of linear polarization, including some as high as 90%.Aims.We study the linear polarization for the 14 GRBs observed by POLAR for which statistically robust inferences are possible. Additionally, time-resolved polarization studies are performed on GRBs with sufficient apparent flux.Methods.A publicly available polarization analysis tool, developed within the Multi-Mission Maximum Likelihood framework (3ML), was used to produce statistically robust results. The method allows spectral and polarimetric data from POLAR to be combined with spectral data from theFermiGamma-ray Burst Monitor (Fermi-GBM) and theNeil Gehrels SwiftObservatory to jointly model the spectral and polarimetric parameters.Results.The time-integrated analysis finds all results to be compatible with low or zero polarization with the caveat that, when time-resolved analysis is possible within individual pulses, we observe moderate linear polarization with a rapidly changing polarization angle. Therefore, time-integrated polarization results, while pointing to lower polarization, are potentially an artifact of summing over the changing polarization signal and thus washing out the true moderate polarization. We therefore caution against overinterpretation of any time-integrated results inferred herein and encourage the community to wait for more detailed polarization measurements from forthcoming missions such as POLAR-2 and LEAP.
Evaluation of the Hepatorenal B-Mode Ratio and the “Controlled Attenuation Parameter” for the Detection and Grading of Steatosis
Authors: Moret Antoine , Boursier Jérome , Houssel Debry Pauline , Riou Jérémie , Crouan Anne , Dubois Marine , Michalak Provost Sophie , Aubé Christophe , Paisant Anita 
Published: September 2020

Abstract
Purpose The aim of this study was to evaluate the hepatorenal index ratio of Supersonic Imagine (B-mode ratio) and the controlled attenuation parameter (CAP) of FibroScan for the noninvasive diagnosis and grading of steatosis.
Materials and Methods Two centers prospectively included patients who underwent liver biopsy, B-mode ratio and CAP evaluation all on the same day between June 2017 and July 2019. MRI and histological morphometry were also performed in center 1. Histology (classic semiquantitative score and morphometry) was used as the reference.
Results Concerning the B-mode ratio, the AUROCs for ≥ S1, ≥ S2 and ≥ S3 were respectively 0.896 ± 0.20, 0.775 ± 0.30 and 0.729 ± 0.39 with the best cut-off values being 1.22 for ≥ S1 (Se = 76.4 %, Sp = 93.2 %), 1.42 for ≥ S2 (Se = 70.2 %, Sp = 71.2 %) and 1.54 for ≥ S3 (Se = 68.4 %, Sp = 69.8 %). The correlation between the B-mode ratio and morphometry was moderate (Rs = 0.575, p < 0.001) and the correlation between the B-mode ratio and MRI was good (Rs = 0.613, p < 0.001). Concerning the CAP, the AUROCs for ≥  S1, ≥ S2 and ≥ S3 were 0.926 ± 0.18, 0.760 ± 0.30 and 0.701 ± 0.40, respectively, with the best cut-off values being 271 dB/m for ≥ S1 (Se = 84 %, Sp = 88.2 %), 331 dB/m for ≥ S2 (Se = 64.5 %, Sp = 74.7 %) and 355 dB/m for ≥ S3 (Se = 55.3 %, Sp = 75.1 %). The correlation between the CAP and morphometry and between the CAP and MRI was moderate in both cases (Rs = 0.526, p < 0.001 and Rs = 0.397, p < 0.001, respectively). The B-mode ratio was better at ruling in and the CAP was better at ruling out the disease.
Conclusion B-mode ratio and CAP show similar and good performance for the diagnosis of steatosis (≥ S1). However, both techniques are limited with respect to differentiating mild to moderate (≥ S2) or severe (≥ S3) steatosis.
COVID-19-Induced Cytokine Release Syndrome Associated with Pulmonary Vein Thromboses, Atrial Cardiomyopathy, and Arterial Intima Inflammation
Authors: Goette Andreas , Patscheke Markus , Henschke Frank , Hammwöhner Matthias 
Published: September 2020

AbstractCoronavirus disease 2019 (COVID-19) is a viral disease induced by severe acute respiratory syndrome–coronavirus-2 (SARS-CoV-2), which may cause an acute respiratory distress syndrome (ARDS). First reports have shown that elevated levels of inflammatory cytokines might be involved in the development of organ dysfunction in COVID-19. Here, we can present a case of cytokine release syndrome induced by SARS–CoV-2 causing multiorgan failure and death. Of note, we can report on pulmonary vein thromboses as potential source of cerebrovascular embolic events. Furthermore, we present a specific form of an isolated inflammatory atrial cardiomyopathy encompassing atrial myocardium, perivascular matrix, as well as atrial autonomic nerve ganglia, causing atrial fibrillation, sinus node arrest, as well as atrial clot formation in the right atrial appendage. An associated acute glomerulonephritis caused acute kidney failure. Furthermore, all the described pathologies of organs and vessels were associated with increased local expression of interleukin-6 and monocyte chemoattractant protein-1 (MCP-1). This report provides new evidence about fatal pathologies and summarizes the current knowledge about organ manifestations observed in COVID-19.
Therapeutic Anticoagulation Delays Death in COVID-19 Patients: Cross-Sectional Analysis of a Prospective Cohort
Authors: Ionescu Filip , Grasso-Knight Giovi , Castillo Edward , Naeem Ehsun , Petrescu Ioana , Imam Zaid , Patel Vishal K. , Narasimhan Mangala , Nair Girish B. 
Published: September 2020

AbstractA hypercoagulable state has been described in coronavirus disease 2019 (COVID-19) patients. Others have reported a survival advantage with prophylactic anticoagulation (pAC) and therapeutic anticoagulation (tAC), but these retrospective analyses have important limitations such as confounding by indication. We studied the impact of tAC and pAC compared with no anticoagulation (AC) on time to death in COVID-19. We performed a cross-sectional analysis of 127 deceased COVID-19 patients and compared time to death in those who received tAC (n = 67), pAC (n = 47), and no AC (n = 13). Median time to death was longer with higher doses of AC (11 days for tAC, 8 days for pAC, and 4 days for no AC, p < 0.001). In multivariate analysis, AC was associated with longer time to death, both at prophylactic (hazard ratio [HR] = 0.29; 95% confidence interval [CI]: 0.15 to 0.58; p < 0.001) and therapeutic doses (HR = 0.15; 95% CI: 0.07 to 0.32; p < 0.001) compared with no AC. Bleeding rates were similar among tAC and remaining patients (19 vs. 18%; p = 0.877). In deceased COVID-19 patients, AC was associated with a delay in death in a dose-dependent manner. Randomized trials are required to prospectively investigate the benefit and safety of higher doses of AC in this population.
A Randomised Interventional Study to Compare Autologous and Nonautologous Dural Substitutes Among Traumatic Brain Injury Patients
Authors: Pandit Vir Abhimanyu , Sharma Rajesh Kumar , Bhaskar Suryanarayanan , Kindra Amanjeet Singh , Choudhary Ajay , Gupta LN 
Published: September 2020

Abstract
Objectives To determine and compare the effectiveness and safety of galea-pericranium autologous dural graft with nonautologous polypropylene (G-patch) dural substitute among traumatic brain injury (TBI) patients.
Methods A prospective interventional randomized comparative study was conducted at the Department of Neurosurgery from November 2013 to March 2015 after obtaining approval from the institutional ethicas committee. The study population included 50 cases of TBI which were divided into two groups of 25 each by the randomization technique and were treated either with autologous duraplasty (galea-pericranium) or nonautologous polypropylene (G-patch) dural substitute. The outcomes measured were time to duraplasty, blood loss, hospital stay, and the incidence of complications with the two techniques. The data were entered in a MS Excel spreadsheet and analysis was done using Statistical Package for Social Sciences (SPSS) version 21.0. A p value of < 0.05 was considered statistically significant.
Results The average time to harvest galea-pericranium was 5 minutes. Compared with the patients undergoing G-patch, the patients in group pericranium had comparable duraplasty time (minutes) (34.32 vs. 27.80, p = 0.44), significantly lower drain output (54.8 vs. 74.5, p = 0.017), comparable blood loss (322 vs. 308, p = 0.545), comparable blood transfusion (24% vs. 16%, p = 0.48), significantly lesser duration of hospital stay (8.6 vs. 10.44, p = 0.028), comparable wound infection (8% vs. 16%, p = 0.384), and comparable cerebrospinal fluid (CSF) leak (0% vs. 8%, p = 0.149).
Conclusion The study showed that galea-pericranium and polypropylene dural patch are equally effective and safe dural substitutes in providing a dural seal to minimize the CSF leaks and infections among posttraumatic brain injury patients.
Simplified model and performance analysis for radiant cooling panel with serpentine tube arrangement and thin insulation layer for moisture control in tropical climate
Authors: Ahmad N A , Lim C W 
Published: September 2020

Abstract
Radiant cooling panel (RCP) is widely known to improve thermal comfort and has the potential for energy saving. However, when applied the system in countries with a tropical climate, a major issue arises which is condensation on the surface panel. In this paper, a simplified model of top insulated RCP panel with serpentine tube arrangement integrated with thin insulation layer is developed to predict its performance. The numerical model is based on the principle of superposition of heat resistance and validated by using simulation software. The result produced by both models shows a good match in which the relative error calculated were 1.3% and 2.7% for cooling capacity and surface mean temperature respectively. Thus, the correctness of the numerical model to determine the cooling capacity and surface mean temperature of radiant cooling panel is validated. The thickness of the thin insulation layer plays a significant role as moisture control while maintaining the cooling capacity at 767W for surface mean temperature of 18.2ºC. When comparing various materials used as the thin insulation layer in RCP, it is also found that RCP with gypsum used as the thin insulation layer demonstrates better performance in maintaining the cooling capacity of RCP while controlling moisture condensation.
Research on robot arm control based on Unity3D machine learning
Authors: Lin Mu , Shan Lijun , Zhang Yongchun 
Published: September 2020

Abstract
Based on the Unity3D engine, the article uses deep reinforcement learning strategies to train the robotic arm through the reward function, and realizes machine learning and intelligent control of the robotic arm. After training and learning, the robotic arm can quickly and accurately find movement point in the environment and has high environmental adaptability. The application of powerful deep reinforcement learning strategies and virtual reality technology in engineering technology teaching has improved the teaching effect and teaching efficiency of mechanical structure cognition, curriculum design and other teaching links.
Fatigue life analysis of key equipment for high temperature reactor under variable working conditions
Authors: Chen Wen , Zhang Yanpeng , Qing Chen , Geng Jie 
Published: September 2020

Abstract
For the high temperature reactor with helium gas in the nuclear power plant, this paper has analysed the stress changes and temperature changes of the key equipment in the reactor under the changing conditions of the actual operation of the critical equipment [1-3]. Based on the threshold value that can satisfy the normal work, according to the expansion mechanism of fatigue crack in fracture mechanics, combined with the actual material parameters of the inner rod, this paper has prejudged the critical location or key products in the equipment, and the location and timing of their work tolerance limits. This paper has also calculated their residual fatigue life. It has certain guiding significance for the calculation of residual fatigue life of proprietary equipment in high temperature gas cooled reactor.
Echo signal simulation system
Authors: Gao Feng , Zhang Yang , Wang Zhenshan , Li Guijuan 
Published: September 2020

Abstract
In order to meet the demand of realistic simulation for complex target echo signal in water, the indirect method of frequency domain is employed to simulate the target echo signal in this paper. The plate element method is first used to forecast complex target echo characteristics in typical water. After generating frequency response function data, the data is imported into the echo signal simulation system. The system adopts FPGA real-time signal processing system based on PXIe bus. It receives hydrophone output signal by A/D sampling, extracts the incident acoustic signal and makes frequency domain transformation. After multiplying the transformed signal and frequency response function, scattering echo spectrum is obtained. And then the time domain transformation is made to get the time series of the echo signal. The series is loaded into the transmitting transducer by the power amplifier and the echo signal is simulated. The system has the high fidelity of the model, stable and reliable hardware system, and software system for easy operation.
Dynamic analysis of ISD suspension based on mechanical impedance
Authors: Xu Long , Chen Yijie , Du Fu , Zhang Zichao , Wang Le 
Published: September 2020

Abstract
The development of inerter has brought rapid development of vehicle suspension’s configuration design. More and more inerter vibration isolation networks have been proposed by scholars. As vibration isolation networks became more complex, traditional dynamic model calculations became difficult. So, a mechanical impedance dynamic model was proposed in this paper, which can be applied to the suspension of different vibration isolation networks. At the same time, the influence of the inerter on the frequency of the three-element parallel ISD suspension was studied, which provides a basis for the selection of suspension parameters.
Kinematic analysis and simulation of human upper limb rehabilitation training mechanism
Authors: Mei Ying , Yin Jiaojiao , Shen Zuo 
Published: September 2020

Abstract
A rehabilitation training mechanism of human upper limb is proposed, it consists of the 3-RRS parallel mechanism and the crank-rocker mechanism. First, their degrees of freedom are analyzed. Then, their kinematics are analyzed by analytical method. Finally, the 3-RRS parallel mechanism and the crank-rocker mechanism are simulated with the software UG and SolidWorks respectively, the results of simulation show that the movement path of the handle on the moving platform of the 3-RRS parallel mechanism coincides with the trajectory of the human arm, it can be used for the rehabilitation training of the human shoulder joint. For the crank-rocker mechanism, the center angles of movement path of the rocker and the handle on the connecting-rod are within the range of motion angles of human elbow joint and wrist joint, it can be used for the rehabilitation training of the elbow and wrist joints. They will all produce soft impulses at the beginning and end points, and the soft impulses will increase as the rotating speed of the driving links increases, so their driving links must rotate at a lower speed.
Model research on NOX emission of an ultra-supercritical circulating fluidized bed boiler
Authors: Zhang Peng , Wang Hu , Xin Shengwei , Hu Changhua , Cao Peiqing , Du Jiajun 
Published: September 2020

Abstract
It requires that coal-fired generator units to meet ultra-low emission standards by 2020 in policy of environmental protection in China. Compared with pulverized coal boiler, circulating fluidized bed (CFB) boiler technology has the natural advantage of low NOX emission, which has the ability to directly realize ultra-low NOX emission inside the furnace. To accurately obtain NOX emission characteristics in an ultra-supercritical CFB boiler under construction, model research and experimental verification of NOX emission prediction were carried out in this paper. The results indicate that three models could all predict NOX emission in the CFB boiler, and the deviation among the predicted values calculated by these models can be controlled within 15%. When an ultra-supercritical CFB boiler burns existing engineering coal, NOX emission would be higher than 50 mg/Nm3, which requires structural improvement and operation parameters optimization to ensure that NOX emission inside the furnace of the CFB boiler could directly reach the ultra-low emission standard.
Co-simulation analysis of the single stage screw feedback digital hydraulic cylinder
Authors: Ma Changlin , Hao Lin , Gao Yunguang , Han Yangyang 
Published: September 2020

Abstract
Taking the single-stage spiral feedback digital hydraulic cylinder as the research object, on the basis of analyzing its composition and mechanical feedback mechanism, we explored the idea of collaborative simulation based on AMESim and Simulink software, and finally realized the collaborative simulation of digital hydraulic cylinder. In this simulation, we use AMESim software to build the mechanical and hydraulic models, Simulink software to build the step-in motor model, and integrate the hydraulic model into the Simulink platform environment through the software interface. We can easily change the parameters to analyze its performance, and provide a convenient way for digital hydraulic cylinder performance optimization research.