bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thin-shell approach for modeling superconducting tapes in the H-φ finite-element formulation
Authors: de Sousa Alves Bruno , Lahtinen Valtteri , Laforest Marc , Sirois Frédéric 
Published: December 2021

Abstract
This paper presents a novel finite-element (FE) approach for the electromagnetic modeling of superconducting coated conductors with transport currents. We combine a thin-shell (TS) method to the H-φ-formulation to avoid the meshing difficulties related to the high aspect ratio of these conductors and reduce the computational burden in simulations. The interface conditions in the TS method are defined using an auxiliary 1-D FE discretization of N elements along the thinnest dimension of the conductor. This procedure permits the approximation of the superconductor’s nonlinearities inside the TS in a time-transient analysis. Four application examples of increasing complexity are discussed: (1) single coated conductor, (2) two closely packed conductors carrying anti-parallel currents, (3) a stack of 20 superconducting tapes and (4) a full representation of a high-temperature superconducting tape comprising a stack of thin films. In all these examples, the profiles of both the tangential and normal components of the magnetic field show good agreement with a reference solution obtained with the standard 2-D H-φ-formulation. Results are also compared with the widely used T-A-formulation. This formulation is shown to be dual to the TS model with a single FE (N = 1) in the auxiliary 1-D systems. The increase of N in the TS model is shown to be advantageous at small inter-tape separation and low transport current since it allows the tangential components of the magnetic field to penetrate the thin region. The reduction in computational cost without compromising accuracy makes the proposed model promising for the simulation of large-scale superconducting applications.
Complexes formed in collisions between ultracold alkali-metal diatomic molecules and atoms
Authors: Frye Matthew D , Hutson Jeremy M 
Published: December 2021

Abstract
We explore the properties of three-atom complexes of alkali-metal diatomic molecules with alkali-metal atoms, which may be formed in ultracold collisions. We estimate the densities of vibrational states at the energy of atom–diatom collisions, and find values ranging from 2.2 to 350 K−1. However, this density does not account for electronic near-degeneracy or electron and nuclear spins. We consider the fine and hyperfine structure expected for such complexes. The Fermi contact interaction between electron and nuclear spins can cause spin exchange between atomic and molecular spins. It can drive inelastic collisions, with resonances of three distinct types, each with a characteristic width and peak height in the inelastic rate coefficient. Some of these resonances are broad enough to overlap and produce a background loss rate that is approximately proportional to the number of outgoing inelastic channels. Spin exchange can increase the density of states from which laser-induced loss may occur.
Impact of nonlocal response in plasmonic metasurfaces on four-wave mixing
Authors: Zhang Zhongshuai , Li Xin , Huo Yanyan , Ning Tingyin 
Published: December 2021

Abstract
We report the impact of nonlocal response in metallic nanostructures on four-wave mixing (FWM) process in nonlinear plasmonic metasurfaces which consist of Au nanostrips coupled with Au film spaced by an ultrathin dielectric film. When the dielectric film is linear and FWM only from the Au nanostructures, the FWM efficiency of around two orders of magnitude enhancement is obtained when the nonlocal effect of Au, not the traditionally local Drude model of Au, is considered. However, when the dielectric film is nonlinear and FWM from the Au nanostructures is negligible, the almost half FWM response from the nonlinear metasurface under the nonlocal, not the local model, of Au is confirmed. These results are both ascribed to the different local electric field distributions near the surface of Au nanostructures and in the gap at the local and nonlocal response of Au. The results have an important significance to design ultra-compacted integrated nonlinear optical devices or to explain the experimental measurements of nonlinear response involving plasmonic nanostructures of ultra-small gaps.
The electronic, half-metallic, elastic, and magnetic properties of new PtWZ (Z = In, Tl, Sn, and Pb) half-Heusler alloys via GGA and GGA+mBJ methods
Authors: Özdemir Evren G , Doğruer Semih 
Published: December 2021

Abstract
The first-principle calculations of PtWZ (Z = In, Tl, Sn, and Pb) half-Heusler alloys were calculated by WIEN2k for GGA and GGA+mBJ methods. First, the ferromagnetic (FM) phases were obtained more energetically stable than non-magnetic (NM) and antiferromagnetic (AFM) phases in each alloy. The Curie temperatures of PtWIn, PtWTl, PtWSn, and PtWPb alloys were obtained as 286.98 K, 467.14 K, 721.98 K, and 1114.31 K, respectively, by utilizing the energy differences of the AFM and FM phases. In each method and alloy used, spin-up electrons showed metallic character. In the GGA method, PtW(In, Tl) alloys have direct band gaps of 0.72044 eV and 0.91488 eV in spin-down electrons, while PtW(Sn, Pb) alloys have indirect band gaps of 1.2558 eV and 1.11892 eV, respectively. In the GGA+mBJ method, the bandgap directions in all compounds remained the same. Here, band gaps in PtW(In, Tl, Sn, and Pb) alloys were obtained as 0.99918 eV, 1.15385 eV, 1.42676 eV, and 1.17497 eV, respectively. While the total magnetic moment values of PtW(In, Tl) half-Heusler alloys were obtained as 1.00 μ
B/f.u., the total magnetic moments of PtW(Sn, Pb) alloys were obtained as 2.00 μ
B/f.u. These results are in full agreement with the Slater-Pauling rule. According to elastic calculations, PtWIn, PtWTl, PtWSn, and PtWPb half-Heusler alloys are elastically stable and ductile.
A proposal for wide range wavelength switching process using optical force
Authors: Taghizad Fanid A , Rostami A 
Published: December 2021

AbstractOptomechanical wavelength up-conversion based on optical force and core–shell scattering effects are used to control light coupling between two waveguides. This system consists of two parallel optical waveguides with 20μm lengths suspended on a silica substrate embedded with Ag/Si/SiO2core–shell nanoparticles. By mid-IR plane wave illumination with different intensities and different wavelengths on nanoparticles, scattering would increase and result in an improvement in attractive gradient optical force exerted on waveguides. Via bending waveguides toward each other, visible light propagating in the first waveguide would couple to another. PDMS as a polymer is used to reduce the required power for bending waveguides. Results reveal that when waveguides’ gap equilibrium is 400 nm and wavelengths of control and probe lights are 4.5μm and 0.45μm respectively, about 10.75 mWμm−2power is needed to bend waveguides for total coupling of light between waveguides. The efficiency of the coupled waveguides system is %43.
Graphene sheet with periodic vacancy: A first principles study
Authors: Maikhuri Deepti , Parkash Jai , Abbas Haider 
Published: December 2021

Abstract
We present a comprehensive first-principles study of the electronic structure of graphene sheet with periodic vacancy. We report the structural, electronic, and magnetic properties of the graphene sheet with periodic vacancy that possess 48 C & 28 H atoms. Computational analysis based on density functional theory predicts that the periodic vacancy can modulate the properties of graphene sheet. Results show that periodic vacancies lead to the manipulation of band gap & could be utilized to tailor the electronic properties of the sheet. Also, it is found that, the graphene sheet with periodic vacancy is non-magnetic in nature.
Shape coexistence in 76Se within the neutron–proton interacting boson model
Authors: Mu Cheng-Fu , Zhang Da-Li 
Published: December 2021

Abstract
We have investigated the low-lying energy spectrum and electromagnetic transition strengths in even–even 76Se using the proton–neutron interacting boson model (IBM-2). The theoretical calculation for the energy levels and E2 and M1 transition strengths is in good agreement with the experimental data. Specifically, the excitation energy and E2 transition of

0

2

+

state, which is intimately associated with shape coexistence, can be accurately reproduced. The analysis on low-lying states and the key structure indicators R
1, R
2, R
3 and R
4 and M1 transitions indicates that there is a coexistence between spherical shape and γ-soft shape in 76Se.
Bayesian optimization of peripheral intraneural stimulation protocols to evoke distal limb movements
Authors: Losanno E , Badi M , Wurth S , Borgognon S , Courtine G , Capogrosso M , Rouiller E M , Micera S 
Published: December 2021

Abstract

Objective. Motor neuroprostheses require the identification of stimulation protocols that effectively produce desired movements. Manual search for these protocols can be very time-consuming and often leads to suboptimal solutions, as several stimulation parameters must be personalized for each subject for a variety of target motor functions. Here, we present an algorithm that efficiently tunes peripheral intraneural stimulation protocols to elicit functionally relevant distal limb movements. Approach. We developed the algorithm using Bayesian optimization (BO) with multi-output Gaussian Processes (GPs) and defined objective functions based on coordinated muscle recruitment. We applied the algorithm offline to data acquired in rats for walking control and in monkeys for hand grasping control and compared different GP models for these two systems. We then performed a preliminary online test in a monkey to experimentally validate the functionality of our method. Main results. Offline, optimal intraneural stimulation protocols for various target motor functions were rapidly identified in both experimental scenarios. Using the model that performed best, the algorithm converged to stimuli that evoked functionally consistent movements with an average number of actions equal to 20% of the search space size in both the rat and monkey animal models. Online, the algorithm quickly guided the observations to stimuli that elicited functional hand gestures, although more selective motor outputs could have been achieved by refining the objective function used. Significance. These results demonstrate that BO can reliably and efficiently automate the tuning of peripheral neurostimulation protocols, establishing a translational framework to configure peripheral motor neuroprostheses in clinical applications. The proposed method can also potentially be applied to optimize motor functions using other stimulation modalities.
Linear simulation of magnetohydrodynamic plasma response to three-dimensional magnetic perturbations in high-β
P plasmas
Authors: Chen R. , Lyons B.C. , Weisberg D.B. , Lao L.L. , Ding S. , Sun Y. , Garofalo A.M. , Gong X. , Xu G.S. 
Published: December 2021

Abstract
We report the numerical analyses of the linear magnetohydrodynamics (MHD) plasma response to applied three-dimensional magnetic perturbations (MPs) in a joint DIII-D/EAST collaboration on high-β
P (poloidal beta) plasmas, utilizing the extended-MHD code M3D-C1, with the purpose of gaining a better understanding of the existing experiment in which n = 3 MPs were applied to such high-β
P plasmas attempting to control large-amplitude type-I edge-localized modes (ELMs). These high-β
P plasmas obtained at the DIII-D tokamak feature an upper-biased double-null configuration, a high edge safety factor q
95 ∼ 6.4, and a stable internal transport barrier (ITB), leading to relatively high core pressures. Single-fluid simulations show that the plasma response to n = 3 MPs, including both non-resonant/kinking and resonant components, is significantly weaker than that to n = 1 or 2 MPs. To survey the impact of q
95 on the plasma response to applied MPs, the self-consistent equilibrium-generating workflow for analysis module, developed in the OMFIT integrated modeling framework, is employed to generate a series of equilibria with a wide range of q
95, while other key parameters, including the normalized beta, electron density at the pedestal top, and plasma shape, are kept fixed. Compared to the vacuum response, single-fluid M3D-C1 simulations predict a much more significant decrease in resonant plasma response to the applied n = 3 MPs at the maximum penetration radii as q
95 increases. In contrast to single-fluid simulation results, showing that resonant penetration occurs only near the pedestal top where the E × B toroidal rotation frequency is zero, two-fluid simulations show two comparable resonant penetrations located near the pedestal top and the ITB foot, where the perpendicular electron rotation frequency is zero. Such resonant field penetration near the ITB foot may be responsible for the observed formation of a staircase structure in both the electron density and temperature profiles, and thereby a considerable deterioration in the global plasma performance, when MPs are applied in high-β
P plasmas. Motivated by this numerical work, we provide some ideas for future research, with the purpose of realizing effective ELM control in such high-β
P plasmas in the DIII-D and EAST devices.
In situ leading-edge-induced damages of melting and cracking W/Cu monoblocks as divertor target during long-term operations in EAST
Authors: Zhu Dahuan , Li Changjun , Gao Binfu , Ding Rui , Wang Baoguo , Guo Zongxiao , Xuan Chuannan , Yu Baixue , Lei Yang , Chen Junling , EAST Team the 
Published: December 2021

Abstract
The leading-edge-induced thermal loading effect due to assembly tolerance between neighboring castellated plasma-facing components is a critical issue in fusion devices. Actively cooled ITER-like W/Cu monoblocks were successfully installed for the upper divertor target in EAST which significantly increases the performance of the divertor power exhaust. The misalignment between neighboring monoblocks was formed inevitably during manufacturing and assembly processes, providing a possibility to demonstrate the leading-edge-induced thermal damage. Indeed, the leading-edge-induced melting phenomena of W/Cu monoblocks on upper divertor targets were observed using CCD a camera during plasma discharges with a large number of droplets ejected from the divertor target, which were also identified at the leading edges of W/Cu monoblocks. Not only that, but also many macro cracks with widths of ∼70 μm and depths of <5 mm along radial and toroidal directions were also found universally at the leading edges of W/Cu monoblocks by post-mortem inspection after plasma campaigns. Thermal–mechanical analysis by means of finite element simulation demonstrated that the maximum temperature could reach W melting point under the current projected heat load of ∼3 MW m−2 on flat top surface with large misalignment up to 3 mm at the leading edges. Meanwhile, the high temperature also induced high thermal stress and strain concentration at the center of leading edges, at which thermal fatigue cracking could be initially generated. Such type of cracks at leading edges on W/Cu monoblocks may be unavoidable due to long-term, pulsed fatigue effects. However, the influence of these cracks seems to be acceptable thanks to the limited propagated distance due to the self-castellation effect, which still needs long-term tracking. The in situ leading-edge-induced melting and cracking damage on W/Cu monoblocks of the EAST upper divertor target provides significant insight on understand the leading-edge-induced thermal effect in ITER and future fusion devices.
Comparison of the influence of 2D and 3D geometry of the main chamber on plasma parameters in the SOL of ASDEX Upgrade
Authors: Bock L. , Brida D. , Faitsch M. , Schmid K. , Lunt T. , the ASDEX Upgrade Team  
Published: December 2021

Abstract
In this paper the influence of toroidally asymmetric wall features on plasma solutions for ASDEX Upgrade is investigated by using the 3D scrape-off-layer simulation code EMC3-EIRENE. A comparison of simulation results in a 2D case with a toroidally symmetric first wall and divertor and a 3D case that differs from the 2D setup by including the 3D structure of the poloidal rib-limiters on the low field side of ASDEX Upgrade, highlights notable differences in the main chamber neutral particle distributions, ionisation sources and plasma flow patterns. Both neutral particle distribution and ionisation sources extend poloidally further upwards at the outer mid-plane in the 3D case and the plasma flow is globally influenced by the 3D wall features. Both simulations are conducted with identical input parameters to isolate the influence of wall geometry from other factors. By analysing the transport of neutrals from different poloidal locations it was possible to explain the observed discrepancies by different transport paths for recycled neutrals from the divertor region, only accessible in the 3D version of the wall geometry. Together with observed differences in fall-off lengths for plasma flow and electron temperature at the outer mid-plane, presented results are of key importance for interpreting global impurity migration experiments.
Fluid, kinetic and hybrid approaches for neutral and trace ion edge transport modelling in fusion devices
Authors: Borodin D.V. , Schluck F. , Wiesen S. , Harting D. , Börner P. , Brezinsek S. , Dekeyser W. , Carli S. , Blommaert M. , Van Uytven W. , Baelmans M. , Mortier B. , Samaey G. , Marandet Y. , Genesio P. , Bufferand H. , Westerhof E. , Gonzalez J. , Groth M. , Holm A. , Horsten N. , Leggate H.J. 
Published: December 2021

Abstract
Neutral gas physics and neutral interactions with the plasma are key aspects of edge plasma and divertor physics in a fusion reactor including the detachment phenomenon often seen as key to dealing with the power exhaust challenges. A full physics description of the neutral gas dynamics requires a 6D kinetic approach, potentially time dependent, where the details of the wall geometry play a substantial role, to the extent that, e.g., the subdivertor region has to be included. The Monte Carlo (MC) approach used for about 30 years in EIRENE (Reiter et al 2005 Fusion Sci. Technol.
47 172–86), is well suited to solve these types of complex problems. Indeed, the MC approach allows simulating the 6D kinetic equation without having to store the velocity distribution on a 6D grid, at the cost of introducing statistical noise. MC also provides very good flexibility in terms of geometry and atomic and molecular (A&M) processes. However, it becomes computationally extremely demanding in high-collisional regions (HCRs) as anticipated in ITER and DEMO. Parallelization on particles helps reducing the simulation wall clock time, but to provide speed-up in situations where single trajectories potentially involve a very large number of A&M events, it is important to derive a hierarchy of models in terms of accuracy and to clearly identify for what type of physics issues they provide reliable answers. It was demonstrated that advanced fluid neutral models are very accurate in HCRs, and at least an order of magnitude faster than fully kinetic simulations. Based on these fluid models, three hybrid fluid–kinetic approaches are introduced: a spatially hybrid technique, a micro–macro hybrid method, and an asymptotic-preserving MC scheme, to combine the efficiency of a fluid model with the accuracy of a kinetic description. In addition, A&M ions involved in the edge plasma chemistry can also be treated kinetically within the MC solver, opening the way for further hybridisation by enabling kinetic impurity ion transport calculations. This paper aims to give an overview of methods mentioned and suggests the most prospective combinations to be developed.
Role of E × B drift in double-peak density distribution for the new lower tungsten divertor with unfavorable B
t on EAST
Authors: Jia Guozhang , Wang Huiqian , Xu Guosheng , Wang Liang , Li Ang , Ding Rui , Liu Xiaoju , Si Hang , Yang Qingquan , Tao Yuqiang , Meng Lingyi , Xu Jichan , Yu Lin , Guo Jin , Wang Yifeng , Gan Chunyun , Guo Wenfeng , Zhu Sizheng 
Published: December 2021

Abstract
Doubly peaked density distribution is expected not only to affect the plasma-wetted area at divertor plates, but also to correlate with the upstream density profile and hence characteristics of magnetohydrodynamic activities in tokamak plasmas (Wang et al 2020 Phys. Rev. Lett.
124 195002). Clarifying its origin is important to understand the compatibility between power/particle exhausts in divertor and high-performance core plasmas required by present-day and future tokamak devices. In this paper, we analyze the double-peak density profile appearing in the modeling during the physics design phase of the new lower tungsten divertor for EAST by using a comprehensive 2D SOLPS-ITER code package, including full drifts and currents, with a concentration on an unfavorable magnetic field (ion B × ∇B drift is directed away from the primary X-point). The results indicate that E × B drift induced by the plasma potential gradient near the target, which is closely related to the divertor state, plays essential roles in the formation of a double-peak profile at the target: (1) large enough radial E
p × B drift produces a broadened high-density region; (2) strong poloidal E
r × B drift drives a significant particle sink and creates a valley on the high-density profile. Thus, the simulation results can explain why this kind of doubly peaked density profile is usually observed at the high-recycling divertor regime. In addition, features of the double-peak ion saturation current distribution measured in preliminary experiments testing the new lower tungsten divertor are qualitatively consistent with the simulations.
Numerical Solution of the SEIR Model for Online Game Addiction Problem by Homotopy Perturbation Methods in Students of Junior High School
Authors: Side S , Saman A , Pratama M I , Ramadhan N R , Sanusi W 
Published: December 2021

Abstract
The purpose of this study was to obtain a numerical solution to the Suspected-Exposed-Infected-Recovered (SEIR) model for the problem of online game addiction in Junior High School 3 Makassar students. The SEIR model is built based on assumptions, then performs an analysis to determine the stability of the model and simulation to get a prediction of the number of students online games addiction. This research is an applied research, the method used to obtain the numerical solution of the SEIR model is the Homotopy Perturbation Method and uses secondary data. The results of this study are the numerical solution of the SEIR model of online game addiction with the homotopy perturbation method in Junior High School 3 Makassar students, the solution obtained shown that the number of students who are online games addiction can be suppressed by increasing parental supervision and also providing guidance and counseling. The results of the analysis shown that online game addiction as a result of online learning has increased, but can be suppressed with supervision from students’ parents.