bluuebunny/crossref_metadata_2025_split huggingface dataset:
A critical review of metamaterial in wireless power transfer system
Authors: Rong Cancan , Lu Conghui , Zeng Yingqin , Tao Xiong , Liu Xiaobo , Liu Renzhe , He Xiangrui , Liu Minghai 
Published: May 2021

AbstractWireless power transfer (WPT) is a promising charging method without physical contact for the electronic products energy supply. However, low transfer efficiency, short transmission distance, as well as the electromagnetic (EM) leakage are commonly main bottlenecks of the WPT technology in the practical applications. The electromagnetic metamaterials (EMMMs) used in WPT system have opened up a brand‐new approach for better transfer properties and EM shielding. This paper is intended to provide an overview of the current studies and breakthroughs of the WPT system based on EMMMs. First, we demonstrate the fundamentals of the WPT based on the magnetic resonant coupling. Then, various key considerations of the EMMMs, such as working mechanisms, fabrications have been taken into accounted in detail. Moreover, the applications of EMMM in WPT systems are elaborated. Finally, the technical challenges in connection with working frequency and design miniaturization are investigated in this paper. This novel interdisciplinary technology shows important meanings on the extensive application of energy transmission in the future.
Design and analysis of a novel AC‐side power decoupling circuit
Authors: Yonggao Zhang , Weidong Fu , Peng Liu , Yu Chang , Sheng Yan 
Published: May 2021

AbstractA large amount of second (2ω) ripple power are coupled on the DC bus of a single‐phase inverter due to the output pulsating power. In this paper, a novel AC‐side power decoupling circuit (APDC) based on buck‐boost is proposed for a single‐phase inverter. The circuit is connected in parallel with the AC side of the inverter to realise the local decoupling of the pulsating power on the AC side. The working principle of APDC is elaborated and the switching sequence of APDC is derived. The corresponding pulse energy modulation (PEM) control strategy is designed to precisely control the decoupled power. The feasibility and superiority of the proposed APDC together with the PEM control strategy are finally verified by both the simulation and experimental results obtained on a 200 W single‐phase inverter. The results show that 2ω‐ripple power of the system can be effectively buffered and the capacitor capacity in the inverter system is greatly reduced.
A novel resonant ZVS power converter with self‐driven synchronous rectifier for low‐voltage high‐current applications
Authors: Nourieh Najmehossadat , Sun Yichuang , Simpson Oluyomi 
Published: May 2021

AbstractThis paper presents a novel isolated resonant zero‐voltage switching converter with a self‐driven synchronous rectifier for low‐voltage high‐current applications. The active resonant tank comprises of a transformer leakage inductance, a capacitor and a diode‐connected MOSFET which provides zero‐voltage switching conditions for all switches. Due to the use of leakage inductance of the transformer in both the primary and secondary sides, the resonant tank and the output section require no external inductor, resulting in a major size reduction of the circuit. The proposed converter has the advantages of high efficiency; low switching, conducting, and thermal losses; high switching frequency range and isolation; and small size. To verify the proposed converter, a laboratory prototype was manufactured with satisfactory performance. The practical results show that the power efficiencies of the converter including self‐driven synchronous rectifier for the light load and the full load are 91.9% and 94.95% at output power Pout = 20 W and Pout = 100 W, respectively.
Enhancement of DC‐bus voltage regulation in cascaded converter system by a new sensorless load current feedforward control scheme
Authors: Ali Majid , Yaqoob Muhammad , Cao Lingling , Loo Ka‐Hong 
Published: May 2021

AbstractIt is generally known that, with conventional PI control, the stability and dynamic response performances of a power converter cannot be optimized simultaneously. To overcome this limitation, an uncertainty and disturbance estimator assisted sensorless load current feedforward control for dc‐bus voltage regulation is presented to achieve fast dynamic response to load variations while stability is guaranteed by tuning PI controller. The proposed control scheme is verified on a cascaded converters system comprising a front end dc‐dc DAB converter followed by a single‐phase inverter as an illustrative case. Load‐current feedforward is used to enhance the transient response of the front end DAB converter while an uncertainty and disturbance estimator is used to compensate for any non‐idealities arising from model uncertainties and error in load current estimation. To validate the proposed control scheme, experimental results obtained from a 250‐W cascaded converter system are presented and compared rigorously to the performance of conventional PI control.
PWM techniques for an asymmetric multilevel binary inverter: an FPGA‐based implementation
Authors: Juárez‐Abad José A. , Barahona‐Avalos Jorge L. , Linares‐Flores Jesús 
Published: May 2021

AbstractThis paper deals with the design and implementation of the conventional Level‐Shifted‐PWM (LS‐PWM) and the PWM‐hybrid modulation techniques in a Field‐Programmable Gate Array (FPGA) development card, applicable to binary asymmetric multilevel converters; particularly herein, the Binary‐Asymmetric Cascade Multilevel Inverter is treated (B‐ACMLI). We employ an FPGA‐based switching‐controller to provide pulses for Multilevel Inverter (MLI) power semiconductors via their gate‐drivers. The modulation strategies were implemented via an FPGA with a 32‐bit floating‐point architecture considering the IEEE‐754 standard's recommendations. The portability of the design is ensured using VHDL . The use of embedded RAM blocks minimizes the logical resources consumed into the FPGA, increases overall speed, and reduces power consumption. A comparison is presented in terms of the number of resources used in both modulation techniques. A low‐cost FPGA board named Pipistrello is used. Pipistrello is an FPGA development board for Xilinx Spartan‐6 LX45, designed by Saanlima Electronics. The platform consisting of a single‐phase seven‐level inverter B‐ACMLI hardware prototype. The experimental results show the effectiveness of the approach. As isolated voltage‐sources, photovoltaic modules are used for the experimental setup to the B‐ACMLI.
An interleaved ZVS ultra‐large gain converter for sustainable energy systems applications
Authors: Bagherian Alireza , Nouri Tohid , Shaneh Mahdi , Radmehr Mehdi 
Published: May 2021

AbstractThis paper proposes an interleaved zero‐voltage switching (ZVS) ultra‐large gain converter. By implementing coupled‐inductor (CI) and built‐in transformer (BIT) together with a switched capacitor (SC) voltage multiplier cell (VMC), a higher degree of flexibility is achieved for improvement of step‐up voltage gain in comparison with those in which only one of these magnetic devices is utilised. Furthermore, the imposed voltage across the semiconductors is reduced by adjusting the turns ratio of the implemented CI and BIT. To further improve the efficiency, semiconductor devices with low ON‐state resistance can be used. Moreover, to ensure ZVS turn‐on, active clamp circuits are located in parallel with the main MOSFETs, which realize ZVS for all MOSFETs during an entire switching cycle. Minimizing the input current ripple as well as attenuating the reverse recovery problem of the diodes are the other advantages of this converter. Therefore, the proposed converter is a suitable candidate for those applications requiring high step‐up gain and high conversion efficiency, such as renewable energy systems. To validate the performance of the proposed converter, a 600 W prototype with 22–380 V voltage conversion is designed, fabricated, and tested. Experimental results confirm that the proposed converter outperforms the previously presented ones in terms of the voltage gain and efficiency.
Power output evaluation of a wind–solar farm considering the influence parameters
Authors: Routray Aliva , Mistry Khyati D , Arya Sabha Raj , Chittibabu Baladhandautham 
Published: May 2021

AbstractPower generation from a hybrid wind–solar farm depends on several parameters such as farm location (solar radiation, wind direction, wind speed), layout of farm, shadowing effect and ambient temperature. Based on the location, the hourly uncertain wind speeds and solar radiation are estimated using Kernel density estimation. An irregular crossed wind farm layout is considered for study as it reduces the effective wake effect, produced due to upstream wind turbines. Further solar panels are also fitted onto the wind farm in order to increase the power output using the same land. In this work, the wake analysis includes single as well as multi‐wake model. The output of the solar farm is affected by many parameters like irradiance, wind speed, atmospheric temperature, self‐shadowing of consecutive photovoltaic (PV) panels and turbine shadowing on PV panels. The power output from solar is calculated considering the temperature effect on PV cell, effect of wind speed on solar panel, self‐shadowing of PV panel and shadowing effect of wind turbine on solar panel.
Evaluation of parametric effect on transient stability of a multi‐unit hydroelectric generating system
Authors: Yang Tianyu , Chen Diyi 
Published: May 2021

AbstractTransient stability of a multi‐unit hydroelectric generating system significantly influences the safety operation of power stations. The uncertainty of operating parameter is one of the important factors to influence the system stability during the transient process. For this reason, the target of this paper aims to explore the optimised operating parameter in order to enhance the stability of a multi‐unit hydroelectric generating system. To overcome the limitations of existing methods in literature, a new high‐dimensional, complex and non‐linear dynamic model of the multi‐unit hydroelectric generating system that combines the conventional hydro‐turbine governing system and the shaft system is established. Then, the dynamic behaviour of the proposed system targeting the transient process is exhaustingly investigated with the change of the critical parameters. The calm interval of critical parameters is also determined in order to improve the transient stability of the system. The obtained results not only enrich the theoretical knowledge of transient dynamics but also ensure the safety operation of hydropower stations. Meanwhile, the presented research method, high‐dimensional non‐linear dynamic model and the interesting findings in transient process can promote the development of the theory of non‐linear dynamics.
A novel protection scheme for hybrid transmission systems connected to DFIG‐based wind farms using game theory
Authors: Khalili Mehrdad , Namdari Farhad , Rokrok Esmaeel 
Published: May 2021

AbstractThis paper presents a single‐ended traveling wave‐based fault protection and location method using game theory for a hybrid multi‐terminal transmission system: an overhead line combined with submarine cables. This technique intends to locate and protect a fault regardless of whether it is on the overhead line or submarine cables. Initially, this study investigates the effects of reflection and refraction coefficients of the terminals on the conventional protections based on traveling wave theory. Furthermore, it presents a single‐end method to detect and locate faults on hybrid multi‐terminal transmission systems connected to doubly‐fed induction generator (DFIG) based wind farms. Following that, the extracted traveling waves and the faulty‐segments were discriminated and identified, respectively, using the game theory. Regarding the extraction techniques of the traveling wave, this study also employs two techniques, including discrete wavelet transform (DWT) and mathematical morphology filter (MMF) to process the signals and investigate the sensitivity of the proposed scheme. The results of the simulation studies that used PSCAD/EMTDC confirmed the reliability and accuracy of the proposed protection scheme in all possible types of faults on the overhead line and submarine cables. The proposed technique also signifies noise immunity.
Adaptive scheme protecting renewable‐dominated micro‐grids against usual topology‐change events
Authors: Abbaspour Ehsan , Fani Bahador , Karami‐Horestani Alireza 
Published: May 2021

AbstractMiscoordination and faulty operation are the two main protection challenges of renewable Distributed Generations (DGs) in Distribution Networks (DNs) and Micro‐Grids (MGs). Although various approaches have already been presented in the literature, none of them has proposed a solution for simultaneous impact of DN/MG reconfigurations and DGs’ protection challenges. Topology‐change being a usual method in decreasing power loss or voltage deviations, it would be preferable to have an online adaptive scheme considering all protection challenges together. Hence, the ordinary overcurrent relays using the IEC 61850 protocol capabilities are utilized in an algorithm capable of definitely assigning which relays are responsible for the on‐going fault and which ones are not. That is, the algorithm is applied on a peer‐mode multi‐agent system (MAS) structure. First, the relay agents are classified into radial and loop Virtual Local Area Networks (VLANs). When a relay detects the fault, the MAS will find the responsible VLAN and instantly isolate other VLANs, including their agents. Next, the main and backup relays using the proposed communication map are assigned within the responsible VLAN. Last, a suitable protection algorithm is applied on the selected relays, according to direction of fault current.
Techno‐economic analysis of direct combustion and gasification systems for off‐grid energy supply: A case for organic rankine cycle and dual fluidized‐bed
Authors: Bagherian Mohammad Ali , Mehranzamir Kamyar , Ahmed Jubaer , Nafea Marwan , Nabipour‐Afrouzi Hadi , Wooi Chin‐leong , Beiranvand Pour Amin , Rezania Shahabaldin , Alizadeh Seyed Morteza 
Published: May 2021

AbstractBiomass is one of the most versatile sustainable energy sources. This versatility allows utilization of different biomass feedstock using a verity of conversion techniques. Often, a biomass‐to‐bioenergy conversion method is selected depending on the application, end‐use product, and the type of feedstock. In many applications such as residential energy supply, it is possible to select amongst various technologies. Although, there exist several challenges such as cost‐effectiveness and sustainability that constrains bioenergy development. To this end, this research elaborates on the impacts of different conversion methods on techno‐economic performance of bioenergy systems for residential energy supply. In this context, Organic Rankine Cycle based on direct combustion, and Dual Fluidized‐Bed technology based on gasification were selected for that purpose. A techno‐economic comparative analysis illustrates that the primary product of the system and fuel cost are the two most important factors in feasibility assessment. The negative impact of feedstock price was more severe on the Organic Rankine Cycle. For wood chips prices below 55$/t, Organic Rankine Cycle could be the better option due to lower capital and maintenance costs. In contrast, Dual Fluidized‐Bed could better tolerate the variation of feedstock price; offering 8% lower cost of energy at 65$/t wood chips.
Multi‐satellite autonomous orbit determination by game‐theoretic optimization in space service volume
Authors: Lin Kui , Zhan Xingqun , Yang Rong , Chi Cheng , Chang Jin 
Published: May 2021

AbstractGlobal navigation satellite systems (GNSSs) are increasingly used for multi‐satellite missions in space service volume (SSV). However, the performance of GNSS‐based autonomous orbit determination (AOD) for SSV users is severely constrained by limited measurement accuracy and signal availability. Relative measurement and orbital dynamic models can be used to improve the AOD performance when the estimator is prone to divergence due to the cross‐correlation of the distributed formation network. In this paper, a sequential game‐theoretic (SGT) optimization algorithm is proposed to deal with cross‐correlation issues when fusing the GNSS and relative measurements for dynamic AOD in the SSV field. A four geostationary Earth orbit satellite mission is simulated as the case study for the AOD performance analysis. The conventional sequential covariance intersection (SCI) is also presented for comparison purposes. The simulation results show that with the combination of GNSS and relative measurements with 10 m and 0.1 m precision, the SGT‐based AOD can achieve about 1.9 m three‐dimensional positioning accuracy, which is 80% better than in the GNSS‐only case. It is also demonstrated that the SGT‐based AOD is superior to the SCI‐based AOD by 50% in the fusion of GNSS and relative measurements in the range of 1–10 m and with 0.1–0.001 m accuracy.
Akzeptanz der Videotherapie an einer Ausbildungsambulanz für Verhaltenstherapie für Kinder und Jugendliche in Zeiten der Corona-Pandemie
Authors: Bernheim Dorothee , Keller Ferdinand , Fegert Jörg M. , Sukale Thorsten 
Published: May 2021

ZUSAMMENFASSUNG
Hintergrund Der erste Lockdown der Corona-Pandemie im Frühjahr 2020 erforderte die zeitnahe Etablierung der Videotherapie als digitales Angebot, um Kinder und Jugendliche mit psychotherapeutischen Maßnahmen regelmäßig versorgen zu können.
Methode Kinder und Jugendliche, Sorgeberechtigte und Therapeuten einer verhaltenstherapeutischen Ausbildungsambulanz wurden im Zeitraum von April bis August 2020 gebeten, im Anschluss an jede videobasierte Psychotherapiesitzung einen eigens konstruierten „Fragebogen zur Akzeptanz der Videotherapie“ (FAV) auszufüllen. Der Fragebogen enthält die Skalen „Therapeutische Beziehung“, „Therapeutische Methoden“, „Umgebungsfaktoren“ sowie „Akzeptanz“.
Ergebnis Der Etablierbarkeit einer „therapeutischen Beziehung“ in der Videotherapie stimmten alle 3 Gruppen „völlig zu“. Der Möglichkeit der Umsetzung von Methoden („Therapeutische Technik“), Herstellbarkeit einer konzentrierten Arbeitsatmosphäre („Umgebungsfaktoren“) und Zufriedenheit mit dem Medium Videotherapie („Akzeptanz“) wurde „eher zugestimmt“. Die kritischste Position nahmen die Therapeuten hinsichtlich der Vermittelbarkeit verhaltenstherapeutischer Methoden ein. Prädiktorenanalysen zeigten einen Einfluss von Alter und Geschlecht von Patienten auf die Akzeptanzeinschätzung der Therapeuten.
Schlussfolgerung Es scheint möglich zu sein, im Rahmen der Videotherapie eine therapeutische Beziehung zu etablieren und diese – vor allem auch auf Patientenseite – zufriedenstellend zu gestalten. Die Zufriedenheit der Therapeuten schien von weiteren Faktoren abhängig zu sein, wie der Komplexität des behandelten Störungsbildes oder der Definition eines ausreichenden Sicherheits- und Notfallmanagements. Je routinierter der Umgang mit der Videotherapie, desto kreativer gestaltete sich der Einsatz therapeutischer Methoden. Die Videotherapie kann daher als wertvolle Ergänzung zur herkömmlichen „Face-to-face“-Therapie und als zukunftsweisendes Tool in der Kinder- und Jugendlichenpsychotherapie betrachtet werden.
Prevalence and Clinical Significance of Metabolic Syndrome in Fibromyalgia Patients
Authors: Yahia Mohamed , Makboul Khaled , Ali Hany 
Published: May 2021

ABSTRACT
Background and Objective Fibromyalgia syndrome (FMS) is a distressing clinical condition. Metabolic syndrome (MetS) is a biochemical and clinical condition characterised by visceral obesity, dyslipidaemia, hyperglycaemia and hypertension. The relation between the two conditions is rarely discussed. This study aimed to determine the prevalence of MetS in FMS patients and to uncover its association with the clinical severity of FMS.
Patients and Methods This cross-sectional study included 200 patients with newly diagnosed FMS. The diagnosis of FMS was established on the basis of the American College of Rheumatology (ACR) 2016 revised criteria. Patients were assessed using the validated Arabic version of Fibromyalgia Impact Questionnaire (FIQ). FMS severity was categorised according to FIQ scores into mild (≤45), moderate (>46 and≤65), and severe (>65).
Results The study included 200 FMS patients. They comprised 180 females (90.0%) and 20 males (10.0%). Among the studied patients, there were 96 patients (48.0%) who fulfilled the criteria of MetS diagnosis. A comparison between FMS patients with MetS and patients without MetS revealed a significantly higher Widespread Pain Index (WPI) [median (IQR): 12.0 (10.0–17.0) vs. 9.0 (6.0–11.0), p<0.001], a higher Symptoms Severity Scale (SSS) (10.5±1.04 vs. 8.1±1.8, p<0.001) and a higher FIQ (58.8±20.7 vs. 45.4±16.6) in patients with MetS. Patients with MetS had a significantly higher frequency of severe FMS (31.2 vs. 10.6%, p<0.001). Using binary logistic regression analysis, significant predictors of severe FMS included WPI, SSS and MetS in a univariate analysis. However, in a multivariate analysis, only WPI and SSS remained significant.
ConclusionsThis study found that MetS is prevalent in FMS patients and it may be associated with more severe forms of the disease.
A Series of Nontuberculous Mycobacterial Flexor Tenosynovitis Infections and Cost of Treatment
Authors: Aryee Jomar N.A. , Akinleye Sheriff D. , Ugwu-Oju Obinna C. , Moore Christopher C. , Freilich Aaron M. 
Published: May 2021

Abstract
Background Nontuberculous mycobacteria (NTM) are rare but potentially devastating causes of musculoskeletal infection and impairment in immunocompetent patients.
Purpose Given the sparse body of literature surrounding these infections, we describe a series of patients with and the cost of treatment of upper extremity NTM infections.
Patients and Methods In a retrospective review of seven patients with NTM infections of the upper extremity treated at a university hospital from 2010 to 2019, we assessed patient demographics, exposures, infection characteristics, management course, outcomes, and costs of treatment.
Results Insidious pain and swelling were the most common clinical manifestation of infection. Despite coupled surgical and medical management, recurrence was common. Two patients required amputation, and three others had lasting functional deficits. The most common pathogen was Mycobacterium avium complex (5 of 7). The estimated median charge related to management was $85,126 with a range from $8,361 to $1,66,229.
Conclusions The treatment of NTM infections is complex and expensive. Diagnosis is usually delayed, which further complicates the management of these patients who often suffer from lasting debilitation. Due to its potentially devastating course, NTM infection should be considered and tested for whenever flexor tenosynovitis is suspected. Regardless of initial presentation, our experience suggests that a protocol of serial surgical debridement immediately after tissue diagnosis is necessary for optimal outcomes. Furthermore, NTM infections require collaboration with infectious disease colleagues to guide antimicrobial regimens based on susceptibility testing and therapeutic drug monitoring for the recommended 6 to 12 months of therapy after the final operative debridement.
Level of Evidence This is a Level IV, case series study.