bluuebunny/crossref_metadata_2025_split huggingface dataset:
Resonant topology design method for implantable wireless power transfer system
Authors: Lin Manhao , Qiu Dongyuan , Luo Chengxin , Zhang Bo , Xiao Wenxun 
Published: January 2021

AbstractThe variable load and coil distance of implantable wireless power transfer system lead to unsteady output voltage, and resonant topology for wireless power transfer system is likely to solve this issue. But existing topologies are unable to meet the demands of implantable wireless power transfer system in practice. This paper presented a method to design resonant topologies for implantable wireless power transfer system in detail and proposed a series of topologies. Wireless power transfer systems based on the proposed topologies can achieve load‐independent output voltage. The output voltage is not constrained by the parameter of coils and its load‐independent feature is irrelevant to the coupling coefficient. Besides, a simple output voltage estimation method can be implemented on the transmitting side to monitor output voltage accurately. The characteristics of proposed implantable wireless power transfer systems are compared and the most attractive resonant topology named LCC/PS topology is pointed out. The proposed implantable LCC/PS wireless power transfer system has high power transfer efficiency from 60% to 76.9% at a coil distance of 5 cm when the load varies from 500 to 2500 Ω. An experimental setup is built and its working frequency is 6.78 MHz. The experimental results with acceptable tolerance show the accuracy of theoretical analysis and the excellent performance of the resonant topologies.
Dual‐mode magnetically integrated photovoltaic microconverter with adaptive mode change and global maximum power point tracking
Authors: Mashinchi Maheri Hamed , Vinnikov Dmitri , Chub Andrii , Korkh Oleksandr , Rosin Argo , Babaei Ebrahim 
Published: January 2021

AbstractThis study proposes a high step‐up galvanically isolated dc‐dc converter based on the quasi‐Z‐source (qZS) network. The voltage gain of the converter can change in a wide range. This feature makes the converter suitable for applications with a wide input voltage range. The range of the dc gain is increased by the implementation of the combined energy transfer principle. A reconfigurable structure is used to combine the energy transfer by the isolation transformer and the coupled inductor of the impedance‐source network. The adaptive mode change activates the energy transfer via an additional winding in the qZS network at lower voltages, which results in considerable efficiency improvement. Consequently, the input voltage range of the converter is extended to the values useful in photovoltaic applications impacted by partial shading. The proposed approach is verified in a photovoltaic (PV) microconverter, where the energy harvest from a PV module is possible during shading by enabling the global maximum power point tracking (GMPPT). It is demonstrated that the dual‐mode operation of the converter helps to achieve a flat efficiency curve along with outstanding maximum power point tracking (MPPT) performance.
Lyapunov stability of smart inverters using linearized distflow approximation
Authors: Saha Shammya Shananda , Arnold Daniel , Scaglione Anna , Schweitzer Eran , Roberts Ciaran , Peisert Sean , Johnson Nathan G. 
Published: January 2021

AbstractFast‐acting smart inverters that utilize preset operating conditions to determine real and reactive power injection/consumption can create voltage instabilities (over‐voltage, voltage oscillations and more) in an electrical distribution network if set‐points are not properly configured. In this work, linear distribution power flow equations and droop‐based Volt–Var and Volt–Watt control curves are used to analytically derive a stability criterion using Lyapunov analysis that includes the network operating condition. The methodology is generally applicable for control curves that can be represented as Lipschitz functions. The derived Lipschitz constants account for smart inverter hardware limitations for reactive power generation. A local policy is derived from the stability criterion that allows inverters to adapt their control curves by monitoring only local voltage, thus avoiding centralized control or information sharing with other inverters. The criterion is independent of the internal time‐delays of smart inverters. Simulation results for inverters with and without the proposed stabilization technique demonstrate how smart inverters can mitigate voltage oscillations locally and mitigate real and reactive power flow disturbances at the substation under multiple scenarios. The study concludes with illustrations of how the control policy can dampen oscillations caused by solar intermittency and cyberattacks.
AC optimal power flow with thermal–wind–solar–tidal systems using the symbiotic organisms search algorithm
Authors: Duman Serhat , Li Jie , Wu Lei 
Published: January 2021

AbstractOptimal power flow problem is one of the most important non‐linear problems for power system planning and the operation of existing modern power networks. Recently, the incremental usage of renewable energy sources in power systems has revealed the significance of power system planning. Thus, the aim is to model the AC optimal power flow problem using thermal–wind–solar–tidal energy systems. In this study, uncertainties of wind, solar, and tidal energy systems were simulated using Weibull, Lognormal, and Gumbel probability distribution functions. Furthermore, the study presents solutions to the AC optimal power flow problem by including test cases of stochastic wind, solar, and tidal energy systems involving minimisation of cost function, active power loss, voltage deviation, enhancement of voltage stability, and contingency conditions. The solutions were tested via IEEE 30‐bus and IEEE 118‐bus test systems incorporating renewable energy sources, using different locations according to the selected thermal generating units. The symbiotic organisms search algorithm, which is one of the recently introduced optimisation algorithms, was used to solve the proposed power system planning problem, and simulation results of this algorithm were compared to the results of other algorithms such as the imperialist competitive, harmony search, backtracking search optimisation, and gravitational search algorithms.
Optimal hybrid microgrid sizing framework for the mining industry with three case studies from Australia
Authors: Ellabban Omar , Alassi Abdulrahman 
Published: January 2021

AbstractThe mining industry is showing increasing interest in adding renewable energy sources (RES) to their mines energy mix as one of the principles of sustainable and profitable mining. This paper proposes a systematic and integrative optimal economic hybrid microgrid sizing framework for profitability analysis in off‐grid hybrid renewable‐energy‐based microgrids in the mining industry. The proposed framework is validated with three case studies in different mining locations in Australia based on real market data, investigating various mining site power configurations, and considering the key technical, environmental, and economic considerations. The results highlight the impact of integrating RES in greenfield or brownfield mines in terms of diesel/RES assets sizing and total cost of electricity generation for each scenario, in addition to evaluating the feasibility of grid‐extension to the mining site versus on‐site generation for a greenfield scenario. Sensitivity analysis is carried out to study the impact of varying different input parameters on the system size and cost. The contributions of this research thus provide practical insights on the profitability of hybrid microgrids in mining applications to the various stakeholders such as independent power producers (IPPs), mining facility owners and policy makers.
Electromagnetic and mechanical design of module dual stator brushless doubly‐fed generator for offshore wind turbine
Authors: Wang Hao , Yu Siyang , Jin Shi , Zhang Fengge 
Published: January 2021

AbstractIn order to meet the higher requirements (i.e. large scale, high reliability and direct drive) of generators used for offshore wind turbine, a novel direct drive module dual stator brushless doubly‐fed generator (DSBDFG) with cage‐barrier rotor having many outstanding merits is proposed in this paper. The fundamental structure, operation principle and power flow are presented. The electromagnetic design methods of the proposed generator including power distribution of inner and outer machines, the relationship of pole number, slot number and module number, and winding design are thoroughly investigated. In order to solve the problems in structure brought by module design and reduce the weight as much as possible, a mechanical construction applied for module DSBDFG is proposed. Finally, the correctness of the proposed electromagnetic design method and the stability of the proposed mechanical construction are verified based on finite element analysis respectively.
Understanding the evolution and dust formation of carbon stars in the Large Magellanic Cloud via the JWST
Authors: Marini E. , Dell’Agli F. , Groenewegen M. A. T. , García–Hernández D. A. , Mattsson L. , Kamath D. , Ventura P. , D’Antona F. , Tailo M. 
Published: January 2021

Context. Carbon stars have been, and still are, extensively studied. Given their complex internal structure and their peculiar chemical composition, they are living laboratories in which we can test stellar structure and evolution theories of evolved stars. Furthermore, they are the most relevant dust manufacturers, thus playing a crucial role in the evolution of galaxies.
Aims. We aim to study the dust mineralogy of the circumstellar envelope of carbon stars in the Large Magellanic Cloud (LMC) to achieve a better understanding of the dust formation process in the outflow of these objects. We intend to investigate the expected distribution of carbon stars in the observational planes built with the filters of the Mid-Infrared Instrument (MIRI) mounted onboard the James Webb Space Telescope (JWST) to select the best planes allowing an exhaustive characterisation of the stars.
Methods. We compared the synthetic spectral energy distributions, obtained by modelling asymptotic giant branch stars and the dust formation process in the wind, with the spectra of carbon stars in the LMC, taken with the Infrared Spectrograph onboard the Spitzer Space Telescope. From the detailed comparison between synthetic modelling and observation we characterise the individual sources and derive the detailed mineralogy of the dust in the circumstellar envelope.
Results. The sample of stars considered here is composed of stars of diverse mass, formation epoch, degree of obscuration, and metallicity. We find that precipitation of MgS on SiC seeds is common to all non-metal-poor carbon stars. Solid carbon is the dominant dust component, with percentages above 80% in all cases; a percentage between 10% and 20% of carbon dust is under the form of graphite, the remaining being amorphous carbon. Regarding the observational planes based on the MIRI filters, the colour-magnitude ([F770W]–[F1800W], [F1800W]) plane allows the best understanding of the degree of obscuration of the stars, while the ([F1800W]–[F2550W], [F1800W]) diagram allows better discrimination among stars of different metallicities.
Dynamical friction in Bose-Einstein condensed self-interacting dark matter at finite temperatures, and the Fornax dwarf spheroidal
Authors: Hartman S. T. H. , Winther H. A. , Mota D. F. 
Published: January 2021

Aims. The aim of the present work is to better understand the gravitational drag forces, also referred to as dynamical friction, acting on massive objects moving through a self-interacting Bose-Einstein condensate, also known as a superfluid, at finite temperatures. This is relevant for models of dark matter consisting of light scalar particles with weak self-interactions that require nonzero temperatures, or that have been heated inside galaxies.
Methods. We derived expressions for dynamical friction using linear perturbation theory, and compared these to numerical simulations in which nonlinear effects are included. After testing the linear result, it was applied to the Fornax dwarf spheroidal galaxy, and two of its gravitationally bound globular clusters. Dwarf spheroidals are well-suited for indirectly probing properties of dark matter, and so by estimating the rate at which these globular clusters are expected to sink into their host halo due to dynamical friction, we inferred limits on the superfluid dark matter parameter space.
Results. The dynamical friction in a finite-temperature superfluid is found to behave very similarly to the zero-temperature limit, even when the thermal contributions are large. However, when a critical velocity for the superfluid flow is included, the friction force can transition from the zero-temperature value to the value in a conventional thermal fluid. Increasing the mass of the perturbing object induces a similar transition to when lowering the critical velocity. When applied to two of Fornax’s globular clusters, we find that the parameter space preferred in the literature for a zero-temperature superfluid yields decay times that are in agreement with observations. However, the present work suggests that increasing the temperature, which is expected to change the preferred parameter space, may lead to very small decay times, and therefore pose a problem for finite-temperature superfluid models of dark matter.
How dust fragmentation may be beneficial to planetary growth by pebble accretion
Authors: Drążkowska J. , Stammler S. M. , Birnstiel T. 
Published: January 2021

Context. Pebble accretion is an emerging paradigm for the fast growth of planetary cores. Pebble flux and pebble sizes are the key parameters used in the pebble accretion models.
Aims. We aim to derive the pebble sizes and fluxes from state-of-the-art dust coagulation models and to understand their dependence on disk parameters and the fragmentation threshold velocity, and the impact of those on planetary growth by pebble accretion.
Methods. We used a 1D dust evolution model including dust growth and fragmentation to calculate realistic pebble sizes and mass flux. We used this information to integrate the growth of planetary embryos placed at various locations in the protoplanetary disk.
Results. Pebble flux strongly depends on disk properties including size and turbulence level, as well as the dust aggregates’ fragmentation threshold. We find that dust fragmentation may be beneficial to planetary growth in multiple ways. First of all, it prevents the solids from growing to very large sizes, at which point the efficiency of pebble accretion drops. What is more, small pebbles are depleted at a lower rate, providing a long-lasting pebble flux. As the full coagulation models are computationally expensive, we provide a simple method of estimating pebble sizes and flux in any protoplanetary disk model without substructure and with any fragmentation threshold velocity.
Catalytic Hydrogen Isotope Exchange Reactions in Late-Stage Functionalization
Authors: Shi Hang , Kang Qi-Kai 
Published: January 2021

AbstractThe introduction of deuterium and tritium into molecules is of great importance in drug discovery. Many attempts have been made to develop late-stage hydrogen isotope exchange (HIE) reactions to avoid multistep syntheses using commercially available labeled precursors. In this review, we summarize recent progress in catalytic HIE reactions, with our main focus on their applications in the late-stage labeling of bioactive complex molecules and pharmaceuticals1 Introduction2	Non-Transition-Metal-Catalyzed Hydrogen Isotope Exchange2.1	Organocatalysis2.2	Photoredox Catalysis3	Transition-Metal-Catalyzed Hydrogen Isotope Exchang3.1	Palladium3.2	Ruthenium3.3	Iridium3.4	Other Metals4	Summary
Specific Point-of-Care Testing of Coagulation in Patients Treated with Dabigatran
Authors: Härtig Florian , Birschmann Ingvild , Peter Andreas , Ebner Matthias , Spencer Charlotte , Gramlich Michael , Richter Hardy , Kuhn Joachim , Lehmann Rainer , Blumenstock Gunnar , Zuern Christine S. , Ziemann Ulf , Poli Sven 
Published: January 2021

Abstract
Background and Purpose Accurate and rapid assessment of coagulation status is necessary to guide thrombolysis or reversal of anticoagulation in stroke patients, but commercially available point-of-care (POC) assays are not suited for coagulation testing in patients treated with direct oral anticoagulants (DOACs). We aimed to evaluate the direct thrombin monitoring (DTM) test card by Helena Laboratories (Texas, United States) for anti-IIa-specific POC coagulation testing, hypothesizing that its POC-ecarin clotting time (POC-ECT) accurately reflects dabigatran plasma concentrations.
Methods A prospective single-center diagnostic study (ClinicalTrials.gov-identifier: NCT02825394) was conducted enrolling patients receiving a first dose of dabigatran and patients already on dabigatran treatment. Blood samples were collected before drug intake and 0.5, 1, 2, 8, and 12 hours after intake. POC-ECT was performed using whole blood (WB), citrated blood (CB), and citrated plasma (CP). Dabigatran plasma concentrations were determined by mass spectrometry.
Results In total, 240 blood samples from 40 patients contained 0 to 275 ng/mL of dabigatran. POC-ECT with WB/CB/CP ranged from 20 to 186/184/316 seconds. Pearson's correlation coefficient showed a strong correlation between dabigatran concentrations and POC-ECT with WB/CB/CP (R2
= 0.78/0.90/0.92). Dabigatran concentrations >30 and >50 ng/mL (thresholds for thrombolysis, surgery, and reversal therapy according to clinical guidelines) were detected by POC-ECT with WB/CB/CP (>36/35/45 and >43/45/59 seconds) with 95/97/97 and 96/98/97% sensitivity, and 81/87/94 and 74/60/91% specificity.
Conclusion This first study evaluating DOAC-specific POC coagulation testing revealed an excellent correlation of POC-ECT with actual dabigatran concentrations. Detecting clinically relevant dabigatran levels with high sensitivity/specificity, the DTM assay represents a suitable diagnostic tool in acute stroke, hemorrhage, and urgent surgery.
Endothelial Dysfunction, Atherosclerosis, and Increase of von Willebrand Factor and Factor VIII: A Randomized Controlled Trial in Swine
Authors: Atiq Ferdows , van de Wouw Jens , Sorop Oana , Heinonen Ilkka , de Maat Moniek P. M. , Merkus Daphne , Duncker Dirk J. , Leebeek Frank W. G. 
Published: January 2021

AbstractIt is well known that high von Willebrand factor (VWF) and factor VIII (FVIII) levels are associated with an increased risk of cardiovascular disease. It is still debated whether VWF and FVIII are biomarkers of endothelial dysfunction and atherosclerosis or whether they have a direct causative role. Therefore, we aimed to unravel the pathophysiological pathways of increased VWF and FVIII levels associated with cardiovascular risk factors. First, we performed a randomized controlled trial in 34 Göttingen miniswine. Diabetes mellitus (DM) was induced with streptozotocin and hypercholesterolemia (HC) via a high-fat diet in 18 swine (DM + HC), while 16 healthy swine served as controls. After 5 months of follow-up, FVIII activity (FVIII:C) was significantly higher in DM + HC swine (5.85 IU/mL [5.00–6.81]) compared with controls (4.57 [3.76–5.40], p = 0.010), whereas VWF antigen (VWF:Ag) was similar (respectively 0.34 IU/mL [0.28–0.39] vs. 0.34 [0.31–0.38], p = 0.644). DM + HC swine had no endothelial dysfunction or atherosclerosis during this short-term follow-up. Subsequently, we performed a long-term (15 months) longitudinal cohort study in 10 Landrace–Yorkshire swine, in five of which HC and in five combined DM + HC were induced. VWF:Ag was higher at 15 months compared with 9 months in HC (0.37 [0.32–0.42] vs. 0.27 [0.23–0.40], p = 0.042) and DM + HC (0.33 [0.32–0.37] vs. 0.25 [0.24–0.33], p = 0.042). Both long-term groups had endothelial dysfunction compared with controls and atherosclerosis after 15 months. In conclusion, short-term hyperglycemia and dyslipidemia increase FVIII, independent of VWF. Long-term DM and HC increase VWF via endothelial dysfunction and atherosclerosis. Therefore, VWF seems to be a biomarker for advanced cardiovascular disease.
Quantitative examination of early diabetes by light-emitting diodes light-induced pupillary light reflex
Authors: Yan Y. J. , Tsai Y. C. , Ko M. L. , Lee N. C. , Chiou J. C. , Ou-Yang M. 
Published: January 2021

This study investigated the abnormal pupillary light reflex in patients with early diabetes mellitus (DM) without retinopathy by using a custom-made noninvasive portable pupilometer. The pupilometer recorded and analyzed the pupillary light reflex. Two light intensities, 0.2 cd and 1.2 cd, and four wavelengths of stimulus light—white (400 nm–800 nm), red (640 ± 5 nm), green (534 ± 5 nm), and blue (470 ± 5 nm)—were used to stimulate the pupil for 10 ms. The pupillary response was recorded for 15 s. A total of 40 healthy people and 40 people with DM without retinopathy participated in the experiment at the National Taiwan University Hospital. The mean and standard deviation of DM duration were 4.5 years and 3.9 years. Of the 16 indices, the duration that pupil restores from its minimum size to half of its resting size (DRP), maximum pupil restoration velocity (MRV), and average restoration velocity (ARV) exhibited the most significant differences between the healthy people and those with DM. Compared with healthy participants, DRP was 16.33% higher, and MRV and ARV were 17.45% and 4.58% lower, respectively, in those with DM. This might be attributable to the sympathetic nervous system (SNS) controlling the dilator muscle during the dark-adapted period and relaxing the pupil; the SNS had few degenerated nerve endings in people with DM. The three aforementioned indices might be used to evaluate the severity of autonomic neuropathy in early DM.
Approximation by simple partial fractions in unbounded domains
Authors: Borodin P. A. , Shklyaev K. S. 
Published: January 2021

Abstract
For unbounded simply connected domains

in the complex plane, bounded by several simple curves with regular asymptotic behaviour at infinity, we obtain necessary conditions and sufficient conditions for simple partial fractions (logarithmic derivatives of polynomials) with poles on the boundary of

to be dense in the space of holomorphic functions in

(with the topology of uniform convergence on compact subsets of

). In the case of a strip

bounded by two parallel lines, we give estimates for the convergence rate to zero in the interior of

of simple partial fractions with poles on the boundary of

and with one fixed pole.
Bibliography: 16 titles.
On a conjecture of Teissier: the case of log canonical thresholds
Authors: Elduque E. , Mustaţă M. 
Published: January 2021

Abstract
For a smooth germ of an algebraic variety

and a hypersurface

in

, with an isolated singularity at

, Teissier conjectured a lower bound for the Arnold exponent of

in terms of the Arnold exponent of a hyperplane section

and the invariant

of the hypersurface.
By building on an approach due to Loeser, we prove the conjecture in the case of log canonical thresholds.
Bibliography: 21 titles.