bluuebunny/crossref_metadata_2025_split huggingface dataset:
Winding open‐circuit fault‐tolerant operation of single DC‐link dual‐inverter fed three‐phase open‐end induction motor drive
Authors: Chakrabarti Abanishwar , Saha Ardhendu , Biswas Sujit K. 
Published: May 2021

AbstractThis study presents a winding open‐circuit fault‐tolerant control scheme for an open‐end induction motor drive with common DC bus for dual inverters. The proposed control scheme also permits balanced three‐phase operation of the same motor under healthy operation. It can suppress common mode current easily, yet permits maximum DC bus utilisation in both operating modes. It is mathematically established here that during fault‐tolerant operation, the magnetising current increases by a factor of √3. As a result, the airgap flux during fault‐tolerant operation is same as that during balanced three‐phase operation. An analytical relation is proposed for maximum torque capability of the machine during fault‐tolerant operation, taking into account the limit of winding current to its rated value and increase of magnetising current during such an operation. Extensive mathematical analysis is supported by simulation and experimental results to validate the performance of the proposed scheme during balanced three‐phase operation as well as winding open‐circuit fault‐tolerant operation.
A robust passivity based control strategy for quasi‐resonant converters
Authors: Ayubirad Mostafa Ali , Siavoshani Simin Amiri , Yazdanpanah Mohammad Javad 
Published: May 2021

AbstractThis paper presents a robust passivity‐based control (RPBC) strategy for half‐wave zero‐voltage switching quasi‐resonant (HW‐ZVS‐QR) buck and boost type converters. The proposed controller is based on energy shaping and damping injection. Theoretical analysis shows that the resulted closed‐loop HW‐ZVS‐QRs are globally asymptotically stabilised even if the physical constraint on the magnitude of the control signal is taken into account. Also, an integral function of the output error is added into the feedback path of the conventional passivity‐based control design. As a result, such controller not only offers a global asymptotic stable operation but also provides strong robustness to a wide range of parameter mismatch. It is also demonstrated that the proposed controller stabilises the converter in cases where the widely used linear multiloop controller fails. Finally, some simulation and experimental results comparing the performance of the proposed RPBC with that of the conventional linear multiloop controller are presented.
Tertiary regulation of cascaded run‐of‐the‐river hydropower in the islanded renewable power system considering multi‐timescale dynamics
Authors: Qiu Yiwei , Lin Jin , Liu Feng , Dai Ningyi , Song Yonghua , Chen Gang , Ding Lijie 
Published: May 2021

AbstractTo enable power supply in rural areas and to exploit clean energy, fully renewable power systems consisting of cascaded run‐of‐the‐river hydropower and volatile energies such as photovoltaic (pv) and wind are built around the world. In islanded operation, the primary and secondary frequency controls, that are hydro governors and automatic generation control (AGC), are responsible for the frequency stability. However, due to limited water storage capacity of run‐of‐the‐river hydropower and river dynamics constraints, without coordination between the cascaded plants, the traditional AGC cannot fully exploit the adjustability of hydropower. When imbalances between the volatile energy and load occur, load shedding can be inevitable. To address this issue, this paper proposes a coordinated tertiary control approach by jointly considering power system dynamics and the river dynamics that couples the cascaded hydropower plants. To unify the multi‐timescale dynamics of the power system and river dynamics to establish a controller that coordinates the cascaded plants, the relation between AGC parameters and turbine discharge is approximated by a polynomial surrogate model. The cascaded plants are coordinated by optimising AGC participation factors in a receding‐horizon manner. Simulation of a real‐life system shows the proposed method significantly reduces load loss under pv volatility.
An integrated approach on proton exchange membrane fuel cell performance enhancement combining flower pollination algorithm and nanofluids
Authors: Kumar Priya , Gnanasekar Subashini , Andrews Nirmala Grace , Natarajan Rajasekar 
Published: May 2021

AbstractProton exchange membrane fuel cell (PEMFC) is widely popular for its inherent advantages like low operating temperature, high efficiency, durability, and reliability. However, modelling its characteristics is often restricted by virtue of its shortage of data and strongly coupled multivariate behaviour. At the same time, when operated within its temperature limits, PEMFC systems exhibit maximum efficiency; otherwise, they cause membrane dryness, poor ionic conductivity and less efficiency. Therefore, PEMFC modelling alongside thermal management is of interest in recent years. With the benefits rendered by the metaheuristics algorithm, an integrated approach is emphasised in this work for achieving twin objectives of modelling PEMFC together with thermal management. An aspiration to enhance PEMFC performance via mathematical modelling, flower pollination algorithm for parameter identification as well as thermal conductivity property computation is outlined. Simulated values are experimentally matched using copper‐based nanofluids. The selection of copper (Cu) is justified by its thermal conductivity property and cost. For brevity, synthesis procedure, characterisation and estimation of thermal conductivity property is expounded in methodology. Numerous experimentations on various vol% fractions combinations lying between 0.05% and 0.5% indicate that Cu nanoparticle when dispersed in base fluids such as water and ethylene glycol (EG) substantially improves thermal conductivity property. Especially, among different combinations, nanofluid with EG and water mixture achieves the highest thermal conductivity value of 1.4255.
Frequency security constrained control of power electronic‐based generation systems
Authors: Steinkohl Joachim , Peyghami Saeed , Wang Xiongfei , Davari Pooya , Blaabjerg Frede 
Published: May 2021

AbstractPower grids with high integration of power electronic converters face new issues that have not existed before. The frequency in the power system is highly related to the inertia and the rotational speed of the operational synchronous machines. This is now changing, as the converter‐based generation units are contributing increasingly to the balancing of active power in the modern power grid. Several frequency control designs for the power electronic‐based generation units have been presented in the past. However, optimal control structures and settings are dependent on the current power grid parameters and operation. The converter‐based units allow the transmission system operators to change their behaviour according to their grid requirements much more dynamical than ever before. The paper proposes a new analysis framework that can be utilized to find the best‐suited control settings in converter‐based units to enhance the system frequency reliability. The proposed framework is demonstrated in a study case by varying the settings of one frequency control scheme currently used in wind power plants in the Danish grid codes and validated on the IEEE 24‐Bus reliability test system with additional wind power integration.
Grid integration aspects of wave energy—Overview and perspectives
Authors: Said Hafiz Ahsan , Ringwood John V. 
Published: May 2021

AbstractThe sustained development of wave energy in the past two decades makes it one of the most promising renewable energy resources to be added to the diverse mixture of supply systems. The inherent difficulty of grid integration of wave energy involves various aspects such as suitable control of power converters and power conditioning processes, allowing for the extraction of the best quality power. This paper presents a comprehensive review of different aspects of grid integration of wave energy devices, including classification of wave energy devices based on their impacts on grid integration, grid requirements imposed by the grid codes and storage technologies used for the grid integration of wave energy converters (WECs). This study also analyses various grid integration studies on wave energy converters, with particular emphasis on power converter technology and control. Furthermore, specific attention is given to the combinational studies that use wave energy combined with other renewable resources due to their positive synergies in lowering the costs of energy produced and that hold an opportunity for future research. An economic case is presented for wave energy devices based on value on the grid.
A novel bilayer coordinated control scheme for global autonomous economic operation of islanded hybrid AC/DC microgrids
Authors: Zheng Shunwei , Liao Kai , Yang Jianwei , He Zhengyou , Sun Xiaofei 
Published: May 2021

AbstractThis paper proposes a novel distributed bilayer coordinated control scheme (BCCS) to realize the autonomous economic operation of islanded hybrid AC/DC microgrids, which only requires a sparse communication link. In the lower layer, the optimal power reference iterative algorithm (OPRIA)‐based droop control is proposed to realize the economic dispatch of each subgrid individually, while the frequency of AC subgrid and the bus voltage of DC subgrid are regulated to their rated values. Then, the upper‐layer control for the interlinking converter is designed to achieve the global economic operation of the hybrid AC/DC microgrid through optimizing the exchanging power between AC and DC subgrids. The proposed BCCS has the advantage of reaching the economic operation and frequency/voltage regulation simultaneously for the hybrid AC/DC microgrid. Besides, the proposed BCCS realizes the stable and economic operation with less communication, flexible controllability, and good compatibility of renewable energy sources. Numerical simulation results based on Matlab/Simulink verify the effectiveness and excellent performance of the proposed BCCS even with the integration of renewable energy sources, and the test based on RT‐LAB illustrates the good real‐time performance of the proposed control scheme.
Wide companions to M and L subdwarfs withGaiaand the Virtual Observatory
Authors: González-Payo J. , Cortés-Contreras M. , Lodieu N. , Solano E. , Zhang Z. H. , Gálvez-Ortiz M.-C. 
Published: May 2021

Aims.The aim of the project is to identify wide common proper motion companions to a sample of spectroscopically confirmed M and L metal-poor dwarfs (also known as subdwarfs) to investigate the impact of metallicity on the binary fraction of low-mass metal-poor binaries and to improve the determination of their metallicity from the higher-mass binary.Methods.We made use of Virtual Observatory tools and large-scale public surveys to look inGaiafor common proper motion companions to a well-defined sample of ultracool subdwarfs with spectral types later than M5 and metallicities below or equal to −0.5 dex. We collected low-resolution optical spectroscopy for our best system, which is a binary composed of one sdM1.5 subdwarf and one sdM5.5 subdwarf located at ∼1360 au, and for another two likely systems separated by more than 115 000 au.Results.We confirm one wide companion to an M subdwarf, and infer a multiplicity for M subdwarfs (sdMs) of 1.0−1.0+2.0% for projected physical separations of up to 743 000 au. We also find four M–L systems, three of which are new detections. No colder companion was identified in any of the 219 M and L subdwarfs of the sample, mainly because of limitations on the detection of faint sources withGaia. We infer a frequency of wide systems for sdM5–9.5 of 0.60−0.60+1.17% for projected physical separations larger than 1 360 au (up to 142 400 au). This study shows a multiplicity rate of 1.0−1.0+2.0% in sdMs, and 1.9−1.9+3.7% in extreme M subdwarfs. We did not find any companion for the ultra M subdwarfs of our sample, establishing an upper limit of 5.3% on binarity for these objects.
Interventionelle Therapie der akuten iliofemoralen Thrombose
Authors: Langer Stephan , Regeniter Philipp 
Published: May 2021

ZusammenfassungDer Goldstandard in der Behandlung der Phlebothrombose ist die konservative Therapie mittels Antikoagulation und Kompression. Bei akuten proximalen iliofemoralen Thrombosen mit Beteiligung der Beckenvene muss jedoch hierbei mit einer Inzidenz für das Entstehen eines postthrombotischen Syndroms im Langzeitverlauf von bis zu 70 % gerechnet werden. Zur Prävention eines solchen Folgeschadens rückt neben der selten durchgeführten operativen venösen Thrombektomie in den letzten Jahren zunehmend die interventionelle rekanalisierende Therapie in den Fokus der Behandlungsstrategie. In dieser Übersicht werden die verschiedenen Techniken und aktuellen Entwicklungen dieser Therapie dargestellt und einer kritischen Wertung vor dem Hintergrund der bestehenden Evidenz unterzogen.
Maternal Serum Placental Protein-13 Levels in the Prediction of Pregnancies with Abnormal Invasive Placentation
Authors: Şahin Banuhan , Turhan Uğur , Şahin Buğra , Dağ İsmail , Tinelli Andrea 
Published: May 2021

Abstract
Objective To evaluate whether placental protein-13 (PP-13) measured in the
serum of pregnant women could predict abnormal invasive placentation (AIP)
detected by color Doppler ultrasound (US) and magnetic resonance imaging scan in
addition to the routine US scan during the third trimester.
Materials and methods The prospective case-control study included patients
subdivided in 2 groups: 42 pregnant women with a singleton pregnancy at
28–32 weeks of gestation with only suspected AIP, and 32 healthy
pregnant women. The serum PP-13 levels were measured in both groups using an
enzyme-linked immunosorbent assay (ELISA) method and statistically compared. The
cases of AIP were confirmed by placental histopathological examination
and/or the uterus removed by hysterectomy after elective caesarean
section.
Results Serum PP-13 levels of pregnant women with AIP were significantly
higher (p<0.001) than those of controls (650.32±387.33 vs.
231.43±94.33). Statistical analysis of maternal serum PP-13 levels above
the threshold of 312 pg/ml (measured in the early third trimester)
predicted AIP with 76.2% sensitivity and 75% specificity.
Conclusion Maternal serum PP-13 may have a role in the pathophysiology of
AIP owing to its high serum value in the AIP group. The maternal serum dosage of
PP-13 levels could improve pregnancy management in those patients suspected of
having AIP.
Synthesis of β-Hydroxy Aryl Selenides via Transition-Metal-Free Three-Component Reaction of Arylamines, Elemental Selenium, and Epoxides
Authors: Wang Hongwei , Li Hongchen , Yu Guoqi , Zhou Yun-Bing , Bai Yalong , Hei Yanling , Chen Junwei 
Published: May 2021

AbstractAn efficient protocol for the construction of valuable β-hydroxy aryl selenides from easily available arylamines, elemental selenium, and epoxides through a transition-metal-free radical process is described. A wide variety of β-hydroxy aryl selenides were obtained in good to excellent yields with excellent stereo- and regioselectivity. In this reaction, two C–Se bonds can be built along with the cleavage of a C–N and C–O bond, demonstrating the high step economy and efficiency of this approach.
Role of Diffuse Tensor Imaging in Predicting Outcomes of Decompressive Surgery in Degenerative Cervical Myelopathy—A Prospective Analysis
Authors: Sharma Neeraj , Alugolu Rajesh , Gangapatnam Dinesh , Saradhi Mudumba Vijaya 
Published: May 2021

Abstract
Background Cervical spondylotic myelopathy is a common degenerative disorder of the cervical spine. Assessing the severity of the disease objectively remains a challenge. Advances in magnetic resonance imaging (MRI), especially diffusion tensor imaging (DTI), elucidate the damaged or compressed fiber tracts in the cord. This study is our endeavor to correlate the relationship between clinical features, radiological features with special reference to DTI, and surgical outcome in patients with degenerative cervical myelopathy.
Methods All consecutive patients of cervical spondylotic myelopathy and cord intensity changes in MRI, admitted and treated in the department of neurosurgery during the period of 2016 to 2018, were included and evaluated clinically and radiologically. The clinical evaluation included motor assessment scale (MAS), 30 meters walking, and hand grip. Radiological investigations included additional DTI in 3T MRI and clinical outcome was measured postoperatively after 12 months by modified Japanese Orthopedic Association (mJOA) recovery ratio and MAS scores.
Results The patients age ranged from 30 to 80 years and the mean age of the study population was 55.95 ± 10 years. Patients with fractional anisotropy (FA) < 0.5 had higher grade of Nurick, that is, grade 5 in 4.3%, grade 4 in 65.2%, and grade 3 in 27.1% compared with grade 5 in 0%, grade 4 in 23.5%, and grade 3 in 47.1% in FA > 0.5. Mean mJOA recovery ratio in the group FA > 0.5 was 57.32 whereas it was 38.78 in FA < 0.5.
Conclusion DTI serves as a potential biomarker for predicting the surgical outcome in degenerative cervical myelopathy cases and thereby making the surgical decision precise. FA can be a potential quantitative tool to predict the functional outcome following decompressive surgery for degenerative cervical myelopathy conditions, in particular lower FA values carries poor prognosis.
Survey of Hospital Chargemaster Transparency
Authors: Arvisais-Anhalt Simone , McDonald Samuel , Park Jason Y. , Kapinos Kandice , Lehmann Christoph U. , Basit Mujeeb 
Published: May 2021

Abstract
Background In January 2019, the Centers for Medicare & Medicaid Services (CMS) required hospitals to list their standard charges (chargemasters) publicly in an effort to increase price transparency in health care. Surveying hospital chargemasters may be informative to assess the implementation of this rule and its utility to consumers.
Objective We aimed to compare hospital chargemaster data within a local hospital market where patients would reasonably try to shop or compare services.
Methods We identified and aggregated Dallas County hospital chargemasters available in a database compatible format in May 2019. We manually examined a convenience sampling of 10 common laboratory tests, medications, and procedures.
Results Thirteen hospital chargemasters were identified. Eleven hospitals had chargemasters available in a database compatible format (xlsx or csv). These 11 chargemasters were aggregated into a single file containing 155,576 chargeable items, prices, and descriptions. We observed heterogeneous names and descriptions of synonymous items across institutions, preventing automated comparisons. The examined items revealed a high variation in charges. The largest charge variation for laboratory tests examined included a 2,606% difference (partial thromboplastin time: $18.70–506.00), for medications an 18,617% difference (5-mg tablet of amlodipine: $0.23–43.05), and for procedures a 2,889% difference (circumcision: $252.00–7,532.10). One institution accounted for 27% of the lowest prices and another accounted for 60% of the highest prices.
Conclusion Chargemaster data presentation varied among the hospitals surveyed, making automatic comparison impossible. Chargemaster data are difficult to interpret for health care decisions. Refining the minimum requirements for publishing chargemaster data could increase their utility.
Colloid Cyst Presenting as Head Injury
Authors: Shrivastava Ankur , Bajaj Jitin , Yadav Yad R. , Swamy Narayan M. , Parihar Vijay , Ratre Shailendra , Sinha Mallika , Hedaoo Ketan , Kumar Ambuj , Chauhan Pankaj Singh 
Published: May 2021

AbstractColloid cysts are mucous- or hyaloid-filled lesions with an outer fibrous layer. These are rare developmental and nonneoplastic malformation. They may be found incidentally, while some cases may present with intermittent headache, rapid neurologic deterioration, drop attacks, and even sudden death. Early recognition of this disease may result in lesser mortality. Here, we present a 22-year-old male with a history of fall while driving his two-wheeler. A diagnosis of colloid cyst of the third ventricle with a head injury was made. Colloid cyst presenting with a head injury is exceedingly rare with only five case reports in the literature. This report may help to support surgical intervention in an asymptomatic patient, as the cyst can predispose head injury with serious consequences. It also stresses the importance of a high degree of suspicion when there is any well-defined radiological abnormality in the region of the third ventricle. A colloid cyst may easily be confused with intracranial hemorrhage due to hyperdensity in head trauma. It can be distinguished by the presence of an accompanying traumatic lesion. The cyst usually has well-defined round margins, and the morphologic appearance and density do not change on a follow-up computed tomography (CT) scan, whereas in hemorrhage the density usually regresses with clinical improvement on serial imaging.
COVID-19 pandemic, lockdown, and consequences for a fossil fuel-dominated electricity system
Authors: Khan Imran , Sahabuddin Md. 
Published: May 2021

In South Asian countries, the spread of COVID-19 was not treated seriously until mid-March 2020. Measures similar to those considered in Europe and other developed countries, such as maintaining social distance and lockdowns, were imposed. Lockdowns imposed a significant impact on the power sector, and this has been well explored in the literature for developed countries. A country-specific assessment of the impact of COVID-19 on the energy sector is crucial for future crisis management and underpinning sustainable power sector development plans. The impact of COVID-19 on Bangladesh’s fossil-fuel dominated electricity sector is explored in this study. The analyses were conducted for 2019 and for the pandemic lockdown period in 2020. Daily hourly demand variations for different electricity generation zones in the country were investigated. The impact of these demand variations on greenhouse gas (GHG) emissions was assessed through time-varying carbon intensity analysis. Nationwide, the analysis revealed that the maximum hourly demand reduced by about 14% between 5 and 6 pm whereas the minimum demand reduction (3%–4%) occurred between 7:30 and 8 pm. Peak time demand reduction was found to be minimal during lockdowns. The national absolute GHG emission reduced by about 1075 kt CO2e, an ∼16% reduction compared with that in 2019. Time-varying carbon intensity patterns varied significantly between zones.
Galectin-3 N-terminal tail prolines modulate cell activity and glycan-mediated oligomerization/phase separation
Authors: Zhao Zihan , Xu Xuejiao , Cheng Hairong , Miller Michelle C. , He Zhen , Gu Hongming , Zhang Zhongyu , Raz Avraham , Mayo Kevin H. , Tai Guihua , Zhou Yifa 
Published: May 2021

Significance
The functional role of the N-terminal tail (NT) of galectin-3 (Gal-3) with its numerous proline residues (27 out of 113 in human Gal-3) has remained enigmatic since its discovery. Our study enlightens the galectin field on the role of specific Gal-3 NT prolines and opens a window into understanding the mechanisms of Gal-3 proline polymorphisms (e.g., at P64) in various pathological disorders. In addition, we show that Gal-3 oligomerization, triggered by binding to glycoconjugates either in solution or on the plasma membrane and disrupted endomembranes, is a dynamic process analogous to liquid–liquid phase separation (LLPS). This dynamic behavior of Gal-3 illuminates a mechanism underlying the formation, regulation, and function of clusters of glycosylated cell surface receptors.