bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experiments during AC current transition in ISTTOK and the hypothesis of ballistic runaway electrons
Authors: Malaquias A , Hole M , Henriques R B , Nedzelskiy I S , Plyusnin V V 
Published: July 2022

Abstract
The operation of the Instituto Superior Técnico Tokamak (ISTTOK) in the alternating current (AC) regime is characterized by the presence of a residual plasma density during the current transition, i.e. when the plasma current crosses the zero value. Contrary to what has been reported in other AC experiments, the pressure-like profiles obtained by the heavy ion beam diagnostic (the product of plasma density with a known function of plasma temperature) do not show evidence of the co-existence of two anti-parallel currents. This is also confirmed by the fact that in these experiments the plasma current and the V
loop both cross the zero value at the same instant. The Murakami–Hugill plots reveal that during the transition the plasma current decays faster than the Hugill limit and that the subsequent ramp-up phase is sustained by runaway electron (RE) currents. It is hypothesized that during plasma current decay a population of REs can enter the following semi-cycle of the discharge. A trajectory simulation model including the forces at play shows that the retardation effect of the friction and molecular forces can cause the dampening of REs (within 20 μs) with energy below 1 keV inside the chamber (without external vertical correction magnetic fields), thus ionizing the background gas. Faster REs (above 1 keV) can also contribute to the ionization of the background gas (e.g. within 50 μs for 3 keV energy electrons) but require a vertical magnetic field to balance the gradB and curvature drifts. This could explain why tuning the vertical field and dosing the background pressure to obtain successful AC discharges is usually challenging.
Analytic theory of ideal-MHD vertical displacements in tokamak plasmas
Authors: Yolbarsop A , Porcelli F , Liu Wandong , Fitzpatrick R 
Published: July 2022

Abstract
An analytic derivation of the relevant dispersion relation for vertical displacements in shaped tokamak plasmas is presented, valid for arbitrary values of the ellipticity parameter. The theory is developed within the framework of the reduced ideal-MHD model. A nearby, perfectly conducting wall can provide passive feedback stabilization of vertical displacements on the ideal-MHD timescale. The mechanism for passive stabilization relies on image currents induced on the metallic wall. However, if the plasma extends to the magnetic separatrix, where magnetic X-points are located, as in the case of a divertor tokamak configuration, perturbed axisymmetric currents carried by the plasma in the vicinity of the X-points are triggered. It is shown that these X-point currents can provide passive feedback stabilization, even in the absence of a nearby wall. X-point currents are excited due to the resonant nature of magnetic X-points with respect to toroidal axisymmetric perturbations. An intermediate case, where the plasma boundary is located just inside the magnetic separatrix, is also analyzed, providing additional insight into the stabilization mechanism.
Characterization of strongly coupled plasmas produced in argon supercritical fluids
Authors: Lee Seungtaek , Lee Juho , Yoon Young Dae , Kim Dong Eon , Yun Gunsu 
Published: July 2022

Abstract
Strongly coupled plasmas (SCPs) exist in various places throughout the Universe, examples of which are inertial confinement fusion experiments, Jovian planets’ cores, neutron stars, and white dwarf stars. In recent decades, theoretical and numerical studies have been pursued to characterize the equation of states and thermodynamic properties of SCPs, which are fundamentally different from those of weakly coupled plasmas. One of the essential research topics is energy transport by radiation or opacity. In particular, in a subcritical medium at a low temperature, condensation renders the medium inhomogeneous, which significantly affects the radiation transport or opacity. However, no study has been conducted for opacity in inhomogeneous supercritical fluids (SCFs). A recent study reveals that an inhomogeneous SCF with nanometer-sized clusters and micrometer-sized droplets can be prepared. Here, we experimentally demonstrate that the emission timescale of an SCP in an inhomogeneous SCF is extended by up to 50% compared to that in a homogeneous SCF. This implies that the inhomogeneity of the SCF significantly enhances the photon confinement. This result is expected to draw interest in the investigation of radiation transport or opacity in the inhomogeneous SCF. A better understanding will lead to a method for increasing the brightness and light emission time from a dense plasma.
Permittivity modulation in Si-based PIN diode by electron irradiation
Authors: Wang Yisong , Gong Min , Li Yun , Yang Zhimei , Rong Chenshuo , Huang Mingmin , Ma Yao , Li Jianghuan 
Published: July 2022

Abstract
In this paper, we investigate the influence of defects induced by different doses of electron irradiation on the real part of permittivity of Si-based PIN diodes with a deep-level transient spectrum test. For a more precise result, the relationship between the real part of the permittivity of the sample and the irradiation dose, temperature and annealing is studied. The results show that the real part of the permittivity changes significantly with the irradiation dose and temperature. The absolute value of the real part of the permittivity decreases with the decrease in temperature, and the changing trend decreases after annealing. The deep-level transient spectroscopy results illustrate that different states of defects caused by radiation and annealing have changed the free carrier mobility, free carrier density and charge balance in the material, which means they have a significant impact on the electrical characteristics of the samples. The I–V and C–V curves are obtained through experiments to extract the leakage current and carrier concentration. The I–V characteristic and the permittivity are subjected to temperature-variation analysis.
Flexible ultra-wideband cartoon-shaped antenna based on a composite with customizable dielectric properties
Authors: Deng Hao , Wei Yiqing , Jing Huihui , Zhang Rui , Chen Qinwen , Wang Jiayun , Qu Zeng , Duan Junping , Zhang Binzhen 
Published: July 2022

Abstract
This paper presents a flexible ultra-wideband (UWB) and deformation-insensitive antenna. The proposed antenna was based on a Mickey-shaped patch, a coplanar waveguide fed, and a flexible composite substrate, which was built by a polydimethylsiloxane (PDMS) matrix and short-diameter powders of polytetrafluoroethylene (PTFE), with customizable dielectric properties. Furthermore, PTFE, magnesium oxide, titanium oxide, and zirconia powders were used as four fillers with different weight ratios to modify and control the dielectric properties of the dielectric substrate (the relative permittivity: 2.75–3.07, the dielectric loss tangent: 0.02–0.05), and then we characterized PDMS-based composites through Young’s modulus, Raman spectra, and surface topography. Finally, we fabricated and measured the proposed antenna with the dimensions of 50 mm × 60 mm × 0.5 mm. The measured reflection coefficient curves showed an operating frequency band from 1.9 GHz to 43.5 GHz, and the measured fractional bandwidth reached 183.3%. It was proved that the antenna had stable performance when it was bent or stretched. Moreover, the antenna was simulated and measured in the proximity of the human body, which verified the antenna robustness and safety for use on a human. The proposed UWB and deformation-insensitive antenna is a promising candidate for wearable applications and wireless communication.
Effect of stretch limit change on hyperelastic dielectric actuation of styrene–ethylene/butylene–styrene (SEBS) copolymer organogels
Authors: Lau Gih-Keong , Ren Zhe-Xian , Chiang Kuan-Ting 
Published: July 2022

Abstract
Harder dielectric elastomers are structurally stronger than soft ones but hardly actuate under electrostatic pressure. It remains unclear which property limits harder dielectric elastomers from producing as large actuation as soft ones. This study shows that the change in stretch limit rather than modulus bounds the ultimate dielectric actuation. A larger ultimate stretch warrants a pre-stretched membrane to further thin down and expand biaxially relative to the pre-stretch state. Theory and experiments showed that pre-stretch alters the maximum stretchability and ultimate dielectric actuation. An optimal pre-stretch helps maximize the ultimate actuation close to

2

times radially so long as the corresponding total stretch did not exceed the elastomer’s fracture limit. Hence, a stretchy harder dielectric elastomer stands a chance of producing as large ultimate actuation as soft ones do. To validate the theory, we tested three commercial grades of styrene–ethylene/butylene–styrene copolymers (SEBS) organogels with different oil content and shore hardness. The tests showed that a 20 A-hardness organogel of low toughness actuated less ultimately, but a 10 A-hardness organogel of greater toughness actuated as much as an 8 A-hardness organogel does. This 10 A-hardness SEBS organogel showed an ultimate elongation of 1192%, and 3.1 times the shear modulus and seven times the tensile strength of 3 M VHB 4910. When being optimally pre-stretched for 3.5 times radially, it produced a substantial hyperelastic dielectric actuation up to 104% active areal strain at 277 MV m−1, comparable to the actuation generated by the over-stiffened VHB DEAs. Unlike VHB DEAs, these harder SEBS DEAs generated hyperelastic actuation free from severe viscoelastic drift. The high performance of SEBS organogels can potentially meet the need for forceful artificial muscles to drive bio-inspired robots.
Fractional order mathematical model of monkeypox transmission dynamics
Authors: Peter Olumuyiwa James , Oguntolu Festus Abiodun , Ojo Mayowa M , Olayinka Oyeniyi Abdulmumin , Jan Rashid , Khan Ilyas 
Published: July 2022

Abstract
In this paper, we present a deterministic mathematical model of monkeypox virus by using both classical and fractional-order differential equations. The model includes all of the possible interactions that contribute to disease spread in the population. We investigate the model's stability results in the disease-free case when R
0 < 1. When R
0 < 1, we show that the model is stable, otherwise it is unstable. To obtain the best fit that describes the dynamics of this disease in Nigeria, the model is fitted using the nonlinear least square method on cumulative reported cases of monkeypox virus from Nigeria between January to December 2019. Furthermore, adequate conditions for the existence and uniqueness of the solution of the model have been proved. We run numerous simulations of the proposed monkeypox model with varied input parameters to investigate the intricate dynamics of monkeypox infection under the effect of various system input parameters. We investigate the system's dynamical behavior to develop appropriate infection control policies. This allows the public to understand the significance of control parameters in the eradication of monkeypox in the population. Lowering the order of fractional derivatives has resulted in significant modifications. To the community's policymakers, we offered numerous parameters for the control of monkeypox.
Eco-friendly Green Synthesis of stable ZnO nanoparticles using citrus limon: X-Ray Diffraction Analysis and Optical Properties
Authors: Kem Anamika , Ansari Mohd Rehan , Prathap P , Jayasimhadri M , Peta Koteswara Rao 
Published: July 2022

Abstract
Eco-friendly stable ZnO nanoparticles (NPs) were synthesized by sol-gel method using citrus limon as a chelating agent. The structural analysis and optical properties of ZnO NPs annealed in air ambient at different temperatures ranging from 600 to 900 °C are reported. A detailed x-ray diffraction (XRD) analysis of ZnO NPs has been discussed. Morphological and optical properties of the NPs were investigated using Field Emission Scanning Electron Microscopy (FE-SEM), XRD, Diffuse Reflectance Spectroscopy (DRS), Photoluminescence (PL), Fourier Transform Infrared spectroscopy (FTIR) and Raman Spectroscopy techniques. The FE-SEM reveals that the average particle size of ZnO NPs increased from 62 to 77 nm due to agglomeration of particles or Ostwald ripening which usually happens at high temperature. Physical and microstructural properties such as crystallite size, strain, stress and dislocation density of ZnO NPs were obtained from XRD spectra studies and compared the estimated parameters by various models. It is observed that, the crystallite size increased after annealing and the strain present in NPs is due to defects. Kubelka-Munk function is used to obtain bandgap of NPs from DRS spectra. A slight decrease in the bandgap of ZnO NPs is due to the increase in particle size. PL spectra reveals that the emission around 402 nm near the UV region is attributed to the near band edge emission (NBE) and emission peaks in a visible region is due to the transition of electrons from traps in bandgap to the valence band.
Tuning of band gap by anion variation of Ga2TiX6 (X = Cl, Br, I) for solar cells and renewable energy
Authors: Al-Muhimeed Tahani I , Alzahrani Jameelah , Rouf Syed Awais , Al-Qaisi Samah , Anbarasan Radhakrishnan , Mahmood Q , Albalawi Hind , Alharthi Sarah , Amin Mohammed A , Somaily H H , Morsi Manal 
Published: July 2022

Abstract
Vacancy-ordered double perovskites have been studied vastly for energy applications for the last few decades. In this article, we have investigated the optical and thermoelectric characteristics of Ga2TiX6 (X = Cl, Br, I). The phonons dispersions, formation energy, and tolerance factors reveal dynamic and structural stabilities. The predicted band gaps turn out to be 2.74 eV, 2.0 eV, and 1.32 eV for Ga2TiCl6, Ga2TiBr6, and Ga2TiI6, respectively, corresponding to the absorption bands 275 nm to 413 nm, 365 nm to 539 nm, and 413 nm to 689 nm. Therefore, the absorption band in the entire visible region for Ga2TiI6 makes it an excellent material for solar cells. The optical characteristics are explained by dielectric constants (ε
1, ε
2), absorption coefficient, and dielectric constants. Thermoelectric efficiency is addressed by calculating the figure of merit to highlight the potential of the investigated materials for thermoelectric applications.
A possible subclassification of fast radio bursts
Authors: Guo Han-Yue , Wei Hao 
Published: July 2022

AbstractAlthough fast radio bursts (FRBs) have been an active field in astronomy and cosmology, their origin is still unknown to date. One of the interesting topics is the classification of FRBs, which is closely related to the origin of FRBs. Different physical mechanisms are required by different classes of FRBs. In the literature, they usually could be classified into non-repeating and repeating FRBs. Well motivated by the observations, here we are interested in the possible subclassification of FRBs. By using the first CHIME/FRB catalog, we propose to subclassify non-repeating (type I) FRBs into type Ia and Ib FRBs. The distribution of type Ia FRBs is delayed with respect to the cosmic star formation history (SFH), and hence they are probably associated with old stellar populations, while the distribution of type Ib FRBs tracks SFH, and hence they are probably associated with young stellar populations. Accordingly, the physical criteria for this subclassification of type I FRBs have been clearly determined. We find that there are some tight empirical correlations for type Ia FRBs but not for type Ib FRBs, and vice versa. These make them different in physical properties. Similarly, we suggest that repeating (type II) FRBs could also be subclassified into type IIa and IIb FRBs. A universal subclassification scheme is given at the end. This subclassification of FRBs might help us to reveal quite different physical mechanisms behind them, and improve their applications in astronomy and cosmology.
Measuring CP violation in rare W decays at the LHC*
Authors: Lu Peng-Cheng , Si Zong-Guo , Wang Zhe , Yang Xing-Hua 
Published: July 2022

Abstract
Heavy Majorana neutrinos beyond the standard model can simultaneously explain the origin of tiny neutrino masses and matter-antimatter asymmetry in our Universe. The existence of heavy Majorana neutrinos will also lead to lepton number violation and confirm the possibility of rare lepton-number-violating W decays. With contributions from two different Majorana neutrinos, nonzero CP asymmetry may be generated from the rate difference between W decay and its CP-conjugate process. The aim of this study is to investigate the prospects of measuring CP violation in rare W decays via Majorana neutrinos at the LHC. Our calculations show that the induced CP asymmetry is independent of the Majorana neutrino mass for

. Such a CP asymmetry, if observed, would in turn provide unambiguous evidence of new physics beyond the standard model.
A New Post-hoc Flat Field Measurement Method for the Solar X-Ray and Extreme Ultraviolet Imager Onboard the FengYun-3E Satellite
Authors: Song Qiao , Bai Xianyong , Chen Bo , Hu Xiuqing , Chen Yajie , Hou Zhenyong , Zhang Xiaofan , He Lingping , Song Kefei , Zhang Peng , Wang Jing-Song , Zhang Xiaoxin , Zong Weiguo , Dun Jinping , Tian Hui , Deng Yuanyong 
Published: July 2022

Abstract
Extreme ultraviolet (EUV) observations are widely used in solar activity research and space weather forecasting since they can observe both the solar eruptions and the source regions of the solar wind. Flat field processing is indispensable to remove the instrumental non-uniformity of a solar EUV imager in producing high-quality scientific data from original observed data. FengYun-3E (FY-3E) is a meteorological satellite operated in a Sun-synchronous orbit, and the routine EUV imaging data from the Solar X-ray and Extreme Ultraviolet Imager (X-EUVI) onboard FY-3E has the characteristic of concentric rotation. Taking advantage of the concentric rotation, we propose a post-hoc flat field measurement method for its EUV 195 Å channel in this paper. This method removes the small-scale and time-varying component of coronal activities by taking the median value for each pixel along the time axis of a concentric rotation data cube, and then derives the large-scale and invariable component of the quiet coronal radiation, and finally generates a flat field image. The flat field can be generated with cadences from hundreds of minutes (one orbit) to several days. Higher flat field accuracy can be achieved by employing more data. Further analysis shows that our method is able to measure the instrumental spot-like non-uniformity possibly caused by contamination on the detector, which mostly disappears after the in-orbit self-cleaning process. It can also measure the quasi-periodic grid-like non-uniformity, possibly from the obscuration of the support mesh on the rear filter. After flat field correction, these instrumental non-uniformities from the original data are effectively removed. Moreover, the X-EUVI 195 Å data after dark and flat field corrections are consistent with the 193 Å imaging data from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory, verifying the suitability of the method. The post-hoc method does not occupy observation time, which is advantageous for space weather operations. Our method is not only suitable for FY-3E/X-EUVI but also a candidate method for the flat field measurement of future solar EUV telescopes.
Effect of Re and Ta on self-trapping of helium in tungsten: a first-principles calculation
Authors: Zhang Luyao , Wang Jiawei , Guo Yue , Zhong Guang , Zhang Zheng , Ren Fei , Xu Zongwei , Shao Jianxiong , Chen Lin , Chen Ximeng , Guo Yanling 
Published: July 2022

Abstract
Self-trapping may play an important role in helium radiation damage of W material in fusion reactors. But the effect of rhenium (Re) and tantalum (Ta) on the self-trapping process in the defect-free tungsten is not clear at present, which has been investigated by the first-principles calculation in this work. The results suggest that He can be trapped by other He atoms without prior defects in the presence of Re/Ta substitutional atom. The substitutional Re atom acts as a trap for the interstitial He clusters and enhances their nucleation, while the Ta atom repulses the large He clusters (n ⩾ 5) and weakens the cluster bonding, thus the growth of He clusters in the vicinity of Ta is not energetically favorable. Moreover, the critical content of He atoms that may trigger the trap mutation decreases when Re exists but increases when Ta exists. These results suggest Re can facilitate the growth of He clusters by self-trapping while Ta has the opposite effects.
Investigation of the structure and properties of aluminum-matrix composite coatings for tribotechnical purposes formed on steel substrates
Authors: Mikheev R S , Kalashnilov I E , Bykov P A , Kobeleva L I 
Published: July 2022

Abstract
The structure and properties of aluminum-matrix composite coatings for tribotechnical purposes, formed on steel substrates, have been investigated. Preliminarily, to limit the interaction between the materials of the substrate and the matrix of the composite material, i.e. iron and aluminum, an intermediate layer of pure aluminum was applied to the substrate surface by the explosion welding process. It is shown that the deposited composite coatings of Al-12Si + 10 wt.% SiC(40) are characterized by a uniform reinforcements distribution, and their adhesion strength values reach 66 MPa. According to the results of friction and wear tests under dry sliding friction conditions, it was determined that the manufactured samples have a 50% higher wear resistance compared to industrial bimetallic materials made of steel 20 with a B83 babbit coating, and their use in friction units will significantly expand the range of triboloading of the promising constructions.
Layout Green Logistics Moving Materials by Gravity
Authors: Alkhaleefah A S 
Published: July 2022

Abstract
The consumption of electricity in industry is receiving a lot of attention as electricity is one of the main drivers in the industry. We can make a huge savings in electricity by using gravity as we always strive for sustainability. Therefore, this paper aims to explore, as an empirical research, the relationship between the type of industry and the moving of materials by gravity, which is known as “green logistics”; using statistical techniques namely Pearson Chi-Square and Likelihood Ratio test. The theme of green logistics was chosen as one of the forms of sustainability.
i.e the use of gravity for handling materials during the manufacturing process, so that it does not consume any electrical energy, but rather moves materials or goods from one "working place" to the next using the force of inclination or humans. The research sample is the factories of the Kingdom of Saudi Arabia, specifically the plastic industries and the furniture industries, this is due to the appropriateness of the material for handling by gravity, moving materials or products regardless of their shape, size or weight. The research will also study the most prominent production stations in which gravity is used, such as packing, packaging, loading and unloading, and others. It is expected that the results of this research will lead to the proposal of some legislation, whether related to the construction of industrial facilities or manufacturing processes, so that these legislations can be adopted, at least in a gradual manner. This topic of research was chosen specifically in view of the modern global trend towards considering sustainability and extending its applications in most aspects of life, including the industrial sector, which consumes about 47% of primary energy. This means that reducing dependence on electricity in a country that accommodate nearly 8,000 factories will be a tangible impact on enhancing the concept of sustainability.