bluuebunny/crossref_metadata_2025 huggingface dataset:
Observational Study of Clinical Practice in Patients with Pancreatic Adenocarcinoma in Greece
Authors: Papaxoinis George , Athanasiadis Athanasios , Sgouros Joseph , Visvikis Anastastios , Drizou Maria , Kontopodis Emmanouil , Koumarianou Anna , Stojanovska Suzana , Aravantinos Gerasimos , Korantzis Ippokratis , Ioannou Alexandros , Varthalitis Ioannis , Doufexis Dimitrios , Nikolaou Michail , Lypas Georgios , Bompolaki Iliada , Christopoulou Athina , Liontos Michael , Tsoukalas Nikolaos , Mauri Davide , Xenidis Nikolaos , Katsaounis Panagiotis , Oikonomopoulos Georgios , Boukovinas Ioannis
Published: September 2020

Background. During the last decade, significant improvement was made in systemic therapy of pancreatic adenocarcinoma (PAC). The impact of this progress in everyday clinical practice has not been fully described yet. The aim of the study was to investigate the pattern followed by Greek Medical Oncologists regarding the treatment of patients with PAC. Methods. This observational, noninterventional multicenter study recorded clinical data from the files of 200 active patients (alive and under treatment or follow-up) for a two-year period (November 2015 until November 2017) from 20 oncology centers around Greece. Results. In total, 51 (25.5%) patients underwent radical surgical resection of PAC, and 40 (78.4%) of them received adjuvant and 1 (2.0%) neoadjuvant chemotherapy. The median time to recurrence was 7.9 months, and median overall survival (OS), 20.2 months. First-line chemotherapy was administered to 193 (96.5%) patients. The majority of patients were treated with the combination of nab-paclitaxel-gemcitabine (NPG), 5-fluorouracil, leucovorin, irinotecan, oxaliplatin (FOLFIRINOX), or gemcitabine monotherapy. Of them, 39.5% responded to the treatment. Median OS and PFS were 14.1 months and 7.0 months, respectively. Second-line treatment was administered to 112 patients. The majority received NPG, FOLFIRINOX/capecitabine, oxaliplatin, irinotecan (CAPOXIRI), or 5-fluorouracil, leucovorin, oxaliplatin (FOLFOX)/capecitabine, oxaliplatin (CAPOX). Median OS with second-line treatment was 8.6 months, and median PFS, 5.5 months. The most common chemotherapy sequences were NPG as first-line followed by FOLFIRINOX/CAPOXIRI as second-line, NPG followed by FOLFOX/CAPOX, NPG followed by other regimens, and FOLFIRINOX/CAPOXIRI followed by NPG. Conclusion. This study described the significant improvement in prognosis of PAC patients receiving palliative chemotherapy and the relatively high rate of receipt of second-line chemotherapy, according to real-world data. However, due to the nonrandomized nature of the study, any comparison between different chemotherapy regimens should be regarded with caution.
Effect of Epoxy Resin Emulsion on the Mechanical Properties of Oil Well Cement‐Based Composites
Authors: He Miao , Song Jianjian , Xu Mingbiao , He Lei , Xu Peng
Published: September 2020

Oil well cement is a brittle material, which can not ensure the long‐term sealing integrity of oil and gas wells when used in cementing operations directly. As a kind of polymer emulsion material, epoxy resin emulsion has a bright future for improving the properties of the cement slurry. Epoxy resin emulsion was added to oil well cement and its workability and mechanical properties were studied, the stress‐strain behavior of cement samples was evaluated, and the microstructure was observed by scanning electron microscope (SEM) and X‐ray diffraction (XRD). The results show the epoxy resin emulsion used in oil well cement will affect the fluidity, but the rheological property of cement slurry with different content of resin meets the construction requirements. The resin reduces the water loss of cement paste and has no adverse effect on the thickening time. The compressive strength of cement stone decreases with the increase in resin content. When the content of resin is 6%, the flexural strength and impact strength of the cement sample are the largest, and 50.7% and 20.2% higher than that of the specimen without resin, respectively, after curing for 28 days. Further comparison shows that epoxy resin emulsion can improve the mechanical properties of oil well cement better than styrene‐butadiene rubber latex. Meanwhile, the resin obviously improves the deformability and decreases the elastic modulus of cement stone. Compared with pure cement, resin cement slurry has no extra hydration products, but the formation of hydrated calcium silicate is inhibited. The microstructure shows that the resin forms a polymer film in the cement matrix and interweaves with cement hydration products, thus improving the flexibility of cement paste.
Characterization of a Bioresorbable Magnesium-Reinforced PLA-Integrated GTR/GBR Membrane as Dental Applications
Authors: Du Xin , Song Yahui , Xuan Xinxin , Chen Shuzhen , Wu Xia , Jiang Heng Bo , Lee Eui-Seok , Wang Xiaohui
Published: September 2020

Inferior mechanical properties have always been a limitation of the bioresorbable membranes in GBR/GTR. This study is aimed at fabricating a bioresorbable magnesium-reinforced polylactic acid- (PLA-) integrated membrane and investigating its mechanical properties, degradation rate, and biocompatibility. The uncoated and fluoride-coated magnesium alloys, AZ91, were made into strips. Then, magnesium-reinforced PLA-integrated membrane was made through integration. PLA strips were used in the control group instead of magnesium strips. Specimens were cut into rectangular shape and immersed in Hank’s Balanced Salt Solution (HBSS) at 37°C for 4, 8, and 12 d. The weight loss of the AZ91 strips was measured. Three-point bending tests were conducted before and after the immersion to determine the maximum load on specimens. Potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) were conducted on coated and uncoated AZ91 plates to examine corrosion resistance. Murine fibroblast and osteoblast cells were cultured on circular specimens and titanium disks for 1, 3, and 5 d. Thereafter, WST test was performed to examine cell proliferation. As a result, the coated and uncoated groups showed higher maximum loads than the control group at all time points. The weight loss of AZ91 strips used in the coated group was lower than that in the uncoated group. PDP, EIS, SEM, and EDS showed that the coated AZ91 had a better corrosion resistance than the uncoated AZ91. The cell proliferation test showed that the addition of AZ91 did not have an adverse effect on osteoblast cells. Conclusively, the magnesium-reinforced PLA-integrated membrane has excellent load capacity, corrosion resistance, cell affinity, and proper degradation rate. Moreover, it has great potential as a bioresorbable membrane in the GBR/GTR application.
Chemical Fingerprint Analysis for Discovering Markers and Identifying Saussurea involucrata by HPLC Coupled with OPLS-DA
Authors: Ma Qingdong , Chen Xiaoxiang , Zhang Ke , Yao Dahong , Yang Lu , Wang Hangyu , Bulemasi Santai , Huang Jian , Wang Jinhui
Published: September 2020

The quality control of Saussurea involucrata has been greatly improved by macroscopic and microscopic identification and chemical profiling described in Chinese Pharmacopoeia since 2005. However, these methods have their own limitations, e.g., their dependence on personal experience and expertise, and it is a huge challenge to identify closely related species that share similar or identical morphological characteristics and chemical profiles. A novel and generally accepted identification strategy is urgently needed as a complement to regulations for protecting the public health interests. In this work, a comprehensive chromatographic fingerprint method was developed and tested on 43 samples from four haplotypes of S. involucrata according to DNA barcoding. Three common patterns consisting of 20, 14, and 7 common peaks were generated by frequency filters of median, upper quartile, and 100%, respectively. Based on two formerly screened patterns, S. involucrata can be effectively identified from its five easily confused snow lotus species, including the most closely related plant (S. orgaadayi) in the orthogonal partial least-squares discriminant analysis (OPLS-DA) models. The model is supported by good R and Q coefficients. In addition, different haplotypes of S. involucrata can be discriminated in the OPLS-DA model using the 20 common peaks. Among them, peaks 9, 11, 16 (zaluzanin C), and 18 (dehydrocostus lactone) have been identified as fingerprint markers of S. involucrata via S-plots and VIP values (>1). Additionally, peaks 19 and 20 were identified as linolenic acid and linoleic acid with anti-inflammatory activity, and they were isolated from the herb for the first time. Collectively, the chromatographic fingerprint of S. involucrata can be an effective and integrated method for the identification of authentic herbs from adulterant species or related plants, and discrimination of its different haplotypes provides an objective and reliable tool for quality control.
On Modeling the Earthquake Insurance Data via a New Member of the T-X Family
Authors: Ahmad Zubair , Mahmoudi Eisa , Kharazmi Omid
Published: September 2020

Heavy-tailed distributions play an important role in modeling data in actuarial and financial sciences. In this article, a new method is suggested to define new distributions suitable for modeling data with a heavy right tail. The proposed method may be named as the Z-family of distributions. For illustrative purposes, a special submodel of the proposed family, called the Z-Weibull distribution, is considered in detail to model data with a heavy right tail. The method of maximum likelihood estimation is adopted to estimate the model parameters. A brief Monte Carlo simulation study for evaluating the maximum likelihood estimators is done. Furthermore, some actuarial measures such as value at risk and tail value at risk are calculated. A simulation study based on these actuarial measures is also done. An application of the Z-Weibull model to the earthquake insurance data is presented. Based on the analyses, we observed that the proposed distribution can be used quite effectively in modeling heavy-tailed data in insurance sciences and other related fields. Finally, Bayesian analysis and performance of Gibbs sampling for the earthquake data have also been carried out.
Route to Chaos and Bistability Analysis of Quasi-Periodically Excited Three-Leg Supporter with Shape Memory Alloy
Authors: Varadharajan Manisekaran , Duraisamy Prakash , Karthikeyan Anitha
Published: September 2020

In this paper, the effect of quasi-periodic excitation on a three-leg supporter configured with shape memory alloy is investigated. We derived the equation of motion for the system using the supporter configuration and polynomial constitutive model of the shape memory alloys (SMAs) based on Falk model. Two sets of parameters and symmetric initial conditions are used to analyze the system. The system responded with a chaotic attractor and a strange nonchaotic attractor. Coexistence of these attractors is studied and discussed with corresponding phase portrait, bifurcation plot, and cross section of basin of attraction. We confirm the quasi-periodic excitation results with generation of strange nonchaotic attractors as discussed in the literature. The special properties like symmetricity and bistability are revealed and the parameter ranges of existence of such behaviors are discussed. The system is analyzed for different phases and the existence of bistability in martensite phase and transition phase is explained. While the system enters into austenite phase, the bistability behavior vanishes. The results provide insight knowledge into dynamical response of a quasi-periodically excited SMA leg support system and will be useful for design improvements and controller design.
Study on Overburden Rock Movement and Stress Distribution Characteristics under the Influence of a Normal Fault
Authors: Wu Quansen , Kong Peng , Wu Quanlin , Xu Xinggang , Wu Xingyu , Guo Tao
Published: September 2020

Fault activation triggers local deformation and dislocation, releasing a large amount of energy that can easily cause mining disasters, such as rock bursts and roadway instability. To study the changing characteristics of overburden structures and the evolution law of mining‐induced stress as panel advances towards a fault from a footwall, two similar models were established, namely, a simulation experimental model and a numerical simulation model. In addition, the relationship among mining, mining stress, and rock bursts induced by fault activation was investigated. The results of this study reveal that when the working face is 30 m away from the fault, the high‐position rock mass near the fault turns to the goaf where the fault is activated, and the two walls display relatively obvious dislocation. During the process of footwall panel mining to the fault, the abutment stress of the coal pillar tends to increase initially, followed by a decrease. When the working face is 20 m away from the fault, the abutment stress ahead of the working face reaches its maximum. When the width of the coal pillar is within the range of 10–40 m, the coal pillar accumulates a large amount of energy, and the working face affected by the fault easily induces a rock burst. Before fault activation, disturbances arising from the mining activities destroy the equilibrium stress environment of the rock system surrounding the fault, and the fault continuously accumulates energy. When the accumulated energy reaches a certain threshold, under the action of normal stress or shear stress, the fault will be activated, and a large amount of energy will be released, which can easily induce a rock burst. The research results in this paper provide a scientific basis for the classification, prediction, and prevention of rock bursts under similar geological conditions.
Study on the Mechanical Behavior of Double Primary Support of Soft Rock Tunnel under High Ground Stresses and Large Deformation
Authors: Liu Zhe
Published: September 2020

Double primary support structures could effectively solve the problem of large deformation of surrounding rock for soft rock tunnels. However, the mechanical behavior of this new support structure is still incomplete, and the design method should be revised. Based on the theory of energy conversion, this paper analyzes the support characteristic curve of double primary support and puts forward the dynamic design method of double primary support. Considering that the secondary lining can be set after monitoring the deformation amount and deformation rate of the first primary support, its support parameters can be dynamically adjusted according to the actual situation. By applying the double primary support design method in the Maoxian tunnel of Chenglan Railway, the field monitoring results show that the double primary support has a significant effect on the energy release of surrounding rocks, greatly reducing the load acting on the secondary lining and ensuring the safety and reliability of the tunnel structure.
Possible Role for Bacteriophages in the Treatment of SARS-CoV-2 Infection
Authors: Mishra Vijaya Nath , Kumari Nidhi , Pathak Abhishek , Chaturvedi Rajnish Kumar , Gupta Arun Kumar , Chaurasia Rameshwar Nath
Published: September 2020

An outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in Wuhan City, China, in December 2019. Since then, the outbreak has grown into a global pandemic, and neither a vaccine nor a treatment for the disease, termed coronavirus disease 2019 (COVID-19), is currently available. The slow translational progress in the field of research suggests that a large number of studies are urgently required. In this context, this review explores the impact of bacteriophages on SARS-CoV-2, especially concerning phage therapy (PT). Bacteriophages are viruses that infect and kill bacterial cells. Several studies have confirmed that in addition to their antibacterial abilities, bacteriophages also show antiviral and antifungal properties. It has also been shown that PT is effective for building immunity against viral pathogens by reducing the activation of NF kappa B; additionally, phages produce the antiviral protein phagicin. The Ganges river in India, which originates from the Himalayan range, is known to harbor a large number of bacteriophages, which are released into the river gradually by the melting permafrost. Water from this river has traditionally been considered a therapeutic agent for several diseases. In this review, we hypothesize that the Ganges river may play a therapeutic role in the treatment of COVID-19.
Elastic, Mechanical, and Phonon Behavior of Orpiment Arsenic Trisulfide under Pressure
Authors: Jiang Liwu , Wu Meiling , Shi Peng , Zhang Chuanhui
Published: September 2020

Arsenic trisulfide (As2S3) has been found to be an excellent glass former at high temperature and pressure. However, there is still some scarcity for the elastic and phonon behavior of the orpiment phase. By using the Dreiding force field of the geometry optimization computations, we investigated the elastic constants, mechanical moduli, and the phonon dispersion of orpiment As2S3 under the pressure from 0 to 5 GPa. Some results of the elastic parameters of orpiment-As2S3 at 0 GPa are consistent with the experimental data. The phonon dispersions for orpiment As2S3 under pressure are also reasonable with previous calculations.
Research on Sewage Monitoring and Water Quality Prediction Based on Wireless Sensors and Support Vector Machines
Authors: Liu Cong , Li Hongji , Zhang Qinkun
Published: September 2020

Water resource protection has an important impact on ecosystem security and human survival. Therefore, water quality testing and early warning of the sewage status are getting more and more attention. In order to solve the problems of information transmission delay and insufficient water quality prediction in current water quality monitoring, this paper proposes a wireless sensor-based dynamic water quality monitoring and prediction technology. Firstly, this paper uses the wireless sensor technology and ZigBee protocol to establish a sewage monitoring model and real-time dynamic monitoring of total nitrogen, total phosphorus, ammonia nitrogen, and other indicators of the water quality of the basin. Secondly, on the basis of wireless monitoring, a support vector algorithm is used to construct a water quality prediction model to make a reasonable prediction of the water quality of the watershed. Finally, the actual test results show that the technology can automatically and real-timely monitor the water quality of the watershed to meet the requirements of water quality monitoring in practical applications.
Study on Microseismic Monitoring, Early Warning, and Comprehensive Prevention of a Rock Burst under Complex Conditions
Authors: Ding Ke , Wang Lianguo , Yu Mei , Wang Wenmiao , Ren Bo
Published: September 2020

Rock bursts in coal mines are usually unpredictable. In view of this problem, the energy–frequency relationship and spatial distribution characteristics of microseismic events during the mining of 5305 working face in Xinhe Coal Mine under complex geological conditions were analyzed in this study. Besides, the law and precursors of rock burst occurrence in this working face were discussed. The following research results were obtained. Before the rock burst occurred in 5305 working face, the energy and frequency of microseismic events vary in the following order: “peak-drop-rise-rock burst.” The analysis on spatial characteristics of microseismic events suggests that microseismic events were mainly concentrated at the boundary between the roof and the coal seam or at the hard roof near the coal seam within 0–160 m in front of the working face, and most of the events lay on the goaf side. Moreover, the energy and frequency of microseismic events both decrease in the above region before the rock burst occurred. This “microseismic event absence” phenomenon can be regarded as one of the precursors of rock burst occurrence. In addition, a multilevel antiburst scheme was proposed for the complex conditions: (1) to adopt large-diameter boreholes pressure relief technology and key layer high-level pressure relief technology for adjusting the stress distribution in the surrounding rock of crossheading in front of the working face and dissipating elastic strain energy; (2) to determine the advance speed to be 1.5 m/d for reducing the mining disturbance; (3) to adopt full-section reinforced support of the roadway for enhancing the antiburst capacity of surrounding rock. After the implementation of this scheme, the energy and frequency of microseismic events monitored on-site changed gently, and 5305 working face was safely recovered to the stop line position. The scheme boasts a remarkable rock burst prevention and control effect.
Stability Analysis and Clinic Phenomenon Simulation of a Fractional-Order HBV Infection Model
Authors: Su Yongmei , Liu Sinuo , Song Shurui , Li Xiaoke , Ye Yongan
Published: September 2020

In this paper, a fractional-order HBV model was set up based on standard mass action incidences and quasisteady assumption. The basic reproductive number R0 and the cytotoxic T lymphocytes’ immune-response reproductive number R1 were derived. There were three equilibrium points of the model, and stable analysis of each equilibrium point was given with corresponding hypothesis about R0 or R1. Some numerical simulations were also given based on HBeAg clinical data, and the simulation showed that there existed positive logarithmic correlation between the number of infected cells and HBeAg, which was consistent with the clinical facts. The simulation also showed that the clinical individual differences should be reflected by the fractional-order model.
[Retracted] Molecular Pathways Involved in Promoting Activity of Timosaponin BII on Hair Growth in C57BL/6 Mice
Authors: Xiao Lei , Zhang Xia , Chen Zhiyi , Li Jianhua , Li Bing , Li Lin
Published: September 2020

Hair loss is a common disease in dermatology, while the approved drugs may have unpredictable side effects. In this study, the effect of timosaponin BII extracted from Anemarrhena asphodeloides on hair growth of C57BL/6 mice was investigated by measuring the hair follicle morphology, hair growth length and area in C57BL/6 male mice, and the immunohistochemical analysis of β‐catenin, Wnt3a, and Wnt10b in the dorsal skins of mice after topical application with minoxidil and timosaponin BII for 15 days. The decrease in skin brightness, the increase in the regrowing area of hair and hair follicles numbers, and the improvement of hair follicle morphology in the group applied with 0.5% timosaponin BII indicated an induction of the anagen phase in telogenic mice skin, which were comparative to the 2% minoxidil treatment. The immunohistochemical analysis detected an increase in the expression of β‐catenin and Wnt10b, supporting the theory of the activation of the β‐catenin/Wnt pathway was one of the pathways that are related to anagen phase induction. Anemarrhena asphodeloides is a herb commonly used for metabolic disorders in China. The present study is the first to show that the timosaponin BII, which is present at a high concentration in A. asphodeloides, promotes hair growth in C57BL/6 male mice. The results indicate that timosaponin BII may be a potential promoting agent for hair growth.
Deep Learning‐Based Safety Helmet Detection in Engineering Management Based on Convolutional Neural Networks
Authors: Li Yange , Wei Han , Han Zheng , Huang Jianling , Wang Weidong
Published: September 2020

Visual examination of the workplace and in‐time reminder to the failure of wearing a safety helmet is of particular importance to avoid injuries of workers at the construction site. Video monitoring systems provide a large amount of unstructured image data on‐site for this purpose, however, requiring a computer vision‐based automatic solution for real‐time detection. Although a growing body of literature has developed many deep learning‐based models to detect helmet for the traffic surveillance aspect, an appropriate solution for the industry application is less discussed in view of the complex scene on the construction site. In this regard, we develop a deep learning‐based method for the real‐time detection of a safety helmet at the construction site. The presented method uses the SSD‐MobileNet algorithm that is based on convolutional neural networks. A dataset containing 3261 images of safety helmets collected from two sources, i.e., manual capture from the video monitoring system at the workplace and open images obtained using web crawler technology, is established and released to the public. The image set is divided into a training set, validation set, and test set, with a sampling ratio of nearly 8 : 1 : 1. The experiment results demonstrate that the presented deep learning‐based model using the SSD‐MobileNet algorithm is capable of detecting the unsafe operation of failure of wearing a helmet at the construction site, with satisfactory accuracy and efficiency.
Influence of Core Thickness and Boundary Condition on the Modal Characteristics of Composite Structure with Metallic Damping Core
Authors: Peng Fuhao , Wu Yiwan , Bai Hongbai , Shao Yichuan , Qin Zhiqiang
Published: September 2020

To reduce the vibration of the plate-like structure under different boundary conditions, an all-metal damping composite structure was proposed, and its damping layer was entangled metallic wire material (EMWM). A series of quasi-static compression tests were carried out to investigate the damping property of the EMWM layer. A modal test system was set up to evaluate whether the EMWM could dissipate vibration energy. The evaluation results showed that the displacement deviation between the baseplate and constraining plate of the structure was large enough and the EMWM could dissipate vibration energy in the form of friction. The modal characteristics of the composite structure with different core thicknesses under different boundary conditions were researched in this paper by experimental modal tests. The outcomes showed that the damping ratio of the structure would be significantly improved by adding EMWM and constraining plate. The larger the thickness of the core thickness is, the larger the damping ratio and vibration reduction performance of the composite structure are. This paper provides a new technical way for the damping design of high temperature plate structure.
Averaging Principles for Nonautonomous Two-Time-Scale Stochastic Reaction-Diffusion Equations with Jump
Authors: Xu Yong , Wang Ruifang
Published: September 2020

In this paper, we aim to develop the averaging principle for a slow-fast system of stochastic reaction-diffusion equations driven by Poisson random measures. The coefficients of the equation are assumed to be functions of time, and some of them are periodic or almost periodic. Therefore, the Poisson term needs to be processed, and a new averaged equation needs to be given. For this reason, the existence of time-dependent evolution family of measures associated with the fast equation is studied and proved that it is almost periodic. Next, according to the characteristics of almost periodic functions, the averaged coefficient is defined by the evolution family of measures, and the averaged equation is given. Finally, the validity of the averaging principle is verified by using the Khasminskii method.
Experimental implementation of a smart battery charger for electric vehicles charging station
Authors: Hassoune Abdelilah , Khafallah Mohamed , Mesbahi Abdelouahed , Nouaiti Ayoub , Bouragba Tarik
Published: September 2020

In this paper, an implementation of a DC/DC buck converter for electric vehicles charging station and a DSP based closed-loop digital controller design are presented and analyzed. The aim of this work is to achieve an improved control strategy for a Li-ion battery charger implemented on a Real-time test platform. The test platform consists of a popular power pole board (MPCA75136) dedicated to studying the DC/DC converters, and a DSP development kit (TMS320F28379D) that is used to drive the DC/DC buck converter. The control strategy is based on a digital control system containing the closed-loop current controller followed by a pulse width modulation block, and on a real time state of charge estimation technique for a Li-ion battery. However, the overall control design is modeled on Simulink via block diagrams, and automatically generated code that is targeted into the DSP processor. Simulation and experimental results have shown the effectiveness of the proposed test bench and its external digital control strategy via a charging scenario for electric vehicles batteries.
Hardware in the loop co-simulation of finite set-model predictive control using FPGA for a three level CHB inverter
Authors: Chung Mai Van , Anh Do Tuan , Vu Phuong , Nguyen Linh Manh
Published: September 2020

Along with the development of powerful microprocessors and microcontrollers, the applications of the model predictive controller, which requires high computational cost, to fast dynamical systems such as power converters and electric drives have become a tendency recently. In this paper, two solutions are offered to quickly develop the finite set predictive current control for induction motor fed by 3-level H-Bridge cascaded inverter. First, the field programmable gate array (FPGA) with capability of parallel computation is employed to minimize the computational time. Second, the hardware in the loop (HIL) co-simulation is used to quickly verify the developed control algorithm without burden of time on hardware design since the motor and the power switches are emulated on a real-time platform with high-fidelity mathematical models. The implementation procedure and HIL co-simulation results of the developed control algorithm shows the effectiveness of the proposed solution.
Improved dead-time elimination method for three-phase power inverters
Authors: Aboelsaud Raef , Ibrahim Ahmed , Garganeev Alexander G. , Aleksandrov Ivan V.
Published: September 2020

In real inverters' operations, it is essential to insert delay time in the pulses provided to the inverter switches to protect the DC link against the short circuits. From this situation, the dead time phenomenon is introduced that causes undesirable performance and distortion of the output signal. Previously, researchers have proposed various schemes for compensating or eliminating dead-time. In this paper, a new dead-time elimination (DTE) scheme is proposed with a guarantee algorithm to eliminate dead-time and overcome the issues produced at the zero-currents-crossing point (ZCC). This method does not require additional hardware or filters to determine the polarity of the output current, and its principle is very simple to implement. The developed DTE method completely removes the dead-time issues on the magnitude and phase of the output voltage, and avoid the problems which can be induced around the ZCC. The results confirm the effectiveness and safety of this method.
Performance evaluation of PI controller for positive output Luo converter
Authors: Ibrahim Muhammed Abduljaleel
Published: September 2020

The aim of this work is to design and analyze a Proportional Integral (PI) controller for Positive Output Luo Converter applications. Positive Output Luo Converter is a developed DC-DC converter. It is respected as a right choice for most industrial application where the rate of the output load voltage must be varying between the low and high values of the input value of voltage, output voltage rise and fall is smaller. This converter involve Power electronics switches (Diodes and MOSFET) since these elements are non-linear. The detailed model includes high-frequency switching that is introducing discontinuities into the model. PI controller coefficients (kp, ki) are calculated by particle swarm optimization (PSO) to provide optimal PI as hybrid PI by PSO controller with simple design procedure .Transient and steady state responses requirement of the system are considered in designing the proposed PI controller. The consequences show that the time of performing characteristics of PSO-PI controller established on integral squared error (ISE) performance index has the best time performing characteristics, line disturbance, load disturbance and set point variation.
Fuzzy logic controller for closed loop cascaded flyback converter fed PMDC-motor system
Authors: Manikandan C.T. , Sundarrajan G.T.
Published: September 2020

This paper displays a Fly Back Converter idea to straightforwardly incorporate cascaded flyback converter. The flyback-converter finds a way between DC-source and DC Motor-load. This work covenants with the modeling, simulation, and application of a Fuzzy Logic controlled (FLC) - Cascaded Fly back Converter (CFLB) system. This work recommends FLC to control Parallel cascaded fly-back converter to fabricate essential DC voltage from the input supply voltage. The yield of CFLB is controlled utilizing closed loop configuration. Closed loop PI & Fuzzy logic controlled CFLB systems are simulated and their results are related. The outcomes signify that the FLC based system gave a superior response than the P.I. controlled CFLB system. The FLC controlled CFLB system has benefits like decreased steady state error and enhanced time domain-response.
ZVS based on dead-time analysis of three port half bridge converters
Authors: Vu Phuong , Nguyen Manh Linh , Pham Viet Phuong
Published: September 2020

In this research, the zero-voltage switching (ZVS) of the GaN FETs-based high frequency three-port half-bridge converter (TPHBC), which is capable of interfacing a renewable energy source, an energy storage and a load is discussed. To achieve ZVS, which plays a key role in power loss reduction of the high switching frequency converters, not only the parasitic elements but also the dead-time between two switches in one converter arm must be taken into account. This research gives a detail analysis about the influence of the dead-time on the ZVS condition. Based on the analysis, a minimum dead-time which guarantees not only the ZVS but also the safe operation of the converter is obtained. Simulations in various load condition of the TPHBC are carried out to verify the validity and effectiveness of the proposed method.
Wireless charging scheme for medium power range application systems
Authors: Karthikeyan D , Koley Sayon , Bagchi Mayukh , Bhattacharya Avijit , Vijayakumar K
Published: September 2020

Wireless power transmission (WPT) has attracted a wide variety of subjects in various disciplines and has also become a highly active research field due to its capacity to facilitate charging systems. Wireless power transmission will be compulsory to use soon as this technology enables electrical energy to be transmitted from a power source to an electrical load over an air gap without connecting wires. Wireless power transmission has been developed in the low power (1W to 10W) and high power (100W-500W) region. While the low power region development focuses on powering medical transplants and mobile charging, the higher end of the power spectrum is being developed for the electric vehicle (EV) applications. However medium power range (10W to 100W) is relatively unexplored due to lack of proper applications. The commercial WPT scheme is mainly used for the charging of lithium-ion batteries. Sensitive medium power loads like Lithium Polymer (LiPo) batteries do not have a wireless modular charging system. This paper discusses a proposed scheme for wireless charging of medium-range loads. LiPo batteries are used as the targeted charging load. A minimalistic approach has been considered while designing the electronics for efficiency improvement and a compact, modular scheme. The proposed scheme has been developed for drone and robotics applications and the results are validated.
Investigation of low voltage DC microgrid using sliding mode control
Authors: Sattianadan D. , Kumar G. R. Prudhvi , Sridhar R. , Reddy Kuthuru Vishwas , Reddy Bhumireddy Sai Uday , Mamatha Panga
Published: September 2020

As the requirement of power increases, the use of renewable energy resources has become prominent. The power collected from these energy resources needs to be converted using AC-DC or DC-DC converters. The control of DC-DC converters is a complex task due to its non-linearity in the converter introduced by the external changes such as source voltage, cable resistance and load variations. Converters are to be designed to obtain a well stabilized output voltage and load current for variable source voltages and load changes. Droop control method is the most abundantly used technique in controlling the parallel converters. The major limitations of the conventional droop control technique are circulating current issues and improper load sharing. The proposed work is to resolve these issues by integrating Sliding Mode Controller (SMC) with the converter in order to enhance the performance of DC microgrid. The entire control system was designed by taking the output voltage error as the control variables. Similarly, droop control with PI and PID were also performed and all these techniques were simulated and compared using MATLAB/Simulink. The experimental results show that the proposed sliding mode controller technique provides good overall performance and is suitable against variable voltage and load changes.
Proposed energy management for a decentralized DC-microgrid based PV-WT-HESS for an isolated community
Authors: Oussama Hafsi , Othmane Abdelkhalek , Mohammed Amine Hartani , Abdesselam Chakar , Mohammed Amine Soumeur
Published: September 2020

Microgrids are small-scale power systems destined to supply isolated villages and optimum utilization of renewable energies. For this reason, this paper presents a DC-MG of 150 Kwp to feed an island village. The configuration of the proposed system consists of four interconnected sub-sections supplied by the centralized unit through PV and Wind Distributed Energy Resources DERs, in addition to the supercapacitor storage device. In the other hand, internal batteries of each sub-section cover its load demand separately, where electrical and chemical storage devices can be advantageous hybrid energy storage system HESS for the system. Thus, the control structure of the DC-MG is based on current hysteresis method to assure the charge/discharge operation and the stability of the DC-bus voltage, then a proposed management strategy to manage the shared energy of the DCMG system. The system behavior is tested under variable parameters and conditions using Matlab/Simulink.
High-voltage DC converter for solar power station
Authors: Qawaqzeh Mohamed , Zaitsev Roman , Miroshnyk Oleksandr , Kirichenko Mykhailo , Danylchenko Dmytro , Zaitseva Liliia
Published: September 2020

In the article the circuit design solution of DC-DC regulated resonant converter has been proposed for using with hybrid photovoltaic modules which has cooling equipment and solar concentrators in order to maximize electric power generating by such module. By using computer simulation based on multiple iterations algorithm we significantly increase the accuracy of determining the resonance circuit optimal parameters for build up DC–DC converters to work in a wide range of electric powers. Based on optimal values of the resonance LLC scheme parameters, achived by numerical calculation it can be show high values of electrical energy transformation efficiency for photovoltaic energy station equipped with high efficiency hybrid photovoltaic modules.  Implementation of microprocessor-based control into design of DC–DC back-boost converters create a new possibility to build control algorithms for increase reliability and conversion efficiency, rapid and precision stabilization of maximum power point, implementation network monitoring of photovoltaic modules, converters itself and the whole photovoltaic station parameters.
A new multilevel inverter with reduced switch count for renewable power applications
Authors: Kim Seong-Cheol , Narasimha S. , Salkuti Surender Reddy
Published: September 2020

This paper proposes a new technique for a voltage source multilevel inverter (MLI) with reduced switch count, and it creates a smoother sinusoidal output waveform with reduced total harmonic distortion (THD). Therefore, the proposed technique identifies a better position in the list of multilevel converters used for power quality conditioners. Semiconducting devices are added to it if the number of levels increases. In this work, the topology of MLI with reduced number of switches is presented. A new MLI is proposed with lower number of switches and sources in order to achieve higher level. The proposed topology is framed out with the combination of three half bridge and a single H-bridge configuration. Detailed simulation results for 15-level inverter of single and three phase inverters are presented in this paper. Three phase 15-level inverter is developed by employing three isolated different renewable sources and 21 switches.
Experimental determination of suboptimal parameters for energy-efficient control of an induction motor
Authors: Goun Valentina S. , Anikin Aleksandr S. , Bakin Aleksey A.
Published: September 2020

The article presents the results of experimental studies of the automatic speed control system (ASCS) of an induction motor (IM). Preliminary experimental studies have shown that the stator current minimum (power factor) is a suboptimal criterion. Optimal in terms of control is the rated power factor. Tests of IM with a thyristor voltage converter (TVC), as a power source, were conducted on an installation created at the department. A mathematical model of ASCS IM corresponding to the experimental setup has been developed. To determine the main functional dependences of IM, such as stator voltage, stator current, power factor, torque on the shaft, a program for approximating experimental data by polynomials was developed. Using the developed mathematical model, the regulatory characteristic of IM that was optimal from an energy point of view was obtained. The necessary indicators of IM and TVC are determined (thyristor control angle, stator voltage, stator current) to change existing settings in order to save electric energy. The results of experimental studies are presented, the graph shows an optimized version of the form of the regulatory characteristic according to the criterion of minimum electric energy consumption.
Direct predictive speed control of permanent magnet synchronous motor fed by matrix converter
Authors: Movahhed Neya Najmeh , Saberi Sajad , Mozafari Babak
Published: September 2020

This paper proposes a non-cascade -single loop- Direct Speed Control algorithm for surface mounted Permanent Magnet Synchronous Motor (PMSM) fed by Matrix Converter. The proposed method uses Finite Control Set Model Predictive Control (FCS-MPC) to manipulate system speed and currents simultaneously. Also, for better performance of the predictive method, an observer designed to estimate mechanical torque and other uncertain parameters of the mechanical subsystem as a lumped disturbance. Simulation results using Matlab/Simulink demonstrate the performance of proposed algorithm.
Modified asymmetrical 13-level inverter topology with reduce power semiconductor devices
Authors: Arif M Saad , Sarwer Zeeshan , Ayob Shahrin Md , Zaid Mohd , Ahmad Shahbaz
Published: September 2020

This paper introduces a modified multilevel inverter topology with asymmetrical dc sources combination. The significant features of the proposed circuit are the reduced number of switches and low total standing voltage (TSV). Proposed topology utilizes ten switches to produce 13 level output with per unit TSVp.u of 5.33. An additional feature of the proposed topology is the inherent negative level generation as there is no requirement of an H-bridge for the polarity reversals. Nearest level control (NLC) technique is used as the modulation strategy. Performance of the proposed topology is validated through extensive analysis using Simulink and PLECS software. Detailed circuit analysis and its power loss, as well as efficiency studies, have been carried out under constant and dynamic load conditions. Results obtained shows that the proposed topology is working well, producing an output of 13-level with total harmonic distortion of 6.36% and inverter efficiency of 98.8%. The topology is extended to n-level structure, and its generalized expressions for different parameters were formulated. The comparison of the generalized structure with other existing topology is carried out, and it is found that the proposed topology outperform other topologies on many parameters.
The Professional Ethics of Witnessing Professionals
Authors: Thompson Dennis F.
Published: September 2020

Professionals have an ethical obligation to bear witness to climate change. They should report, warn, criticize, and lobby to bring attention to the existential threat that climate change poses. But they also have an obligation to respect the knowledge that is the basis of their authority to witness. Witnessing carries risks to this professional authority. Witnessing professionals should avoid letting bias distort their advocacy, simplifying their statements excessively, overplaying the consensus in the field, neglecting their own conflicts of interest, and claiming authority beyond their areas of expertise. To witness ethically, the professional should advocate responsibly.
The identity of the freshwater crab Indochinamon manipurense (Alcock, 1909), with description of a new species of Potamiscus Alcock, 1909, from Manipur State, India (Decapoda, Brachyura, Potamidae)
Authors: Pati Sameer K. , Mitra Santanu , Ng Peter K. L.
Published: September 2020

The identity of the potamid freshwater crab, Indochinamon manipurense (Alcock, 1909) from the state of Manipur in northeast India, is clarified based on an examination of the type specimens. The species is redescribed and a lectotype designated. Specimens from the same region previously referred to this species were compared to the types of I. manipurense and shown to belong to a new species of Potamiscus Alcock, 1909, instead. The new species, Potamiscus takedai sp. nov., can easily be separated from I. manipurense by the characters in the carapace, third maxilliped, male pleon, male gonopods, and female vulvae. Potamiscus takedai sp. nov. can be differentiated from congeners mainly by the strongly bent terminal segment of the male first gonopod and a relatively shorter distal segment of the male second gonopod.
The synonymy of Parasesarma foresti (Rahayu & Davie, 2002) with P. indiarum (Tweedie, 1940) (Decapoda, Brachyura, Sesarmidae)
Authors: Shahdadi Adnan , Davie Peter J. F. , Rahayu Dwi Listyo , Schubart Christoph D.
Published: September 2020

Two Southeast Asian species of Parasesarma De Man, 1895, P. indiarum (Tweedie, 1940) and P. foresti (Rahayu & Davie, 2002), have been reported to be morphologically and genetically very similar. Present comparisons of a range of material show the two species to be identical in male chelar dactylar tuberculation, pleon, and first gonopod characters, all typically used to separate close sibling species in this genus. CO1 genetic distances between the two putative species are also too low to be regarded as interspecific. Parasesarma foresti is thus here regarded as a junior subjective synonym of P. indiarum.