bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal design and analysis of a flexible solar array system based on shape memory polymer composites
Authors: Liu Zhengxian , Hao Sida , Lan Xin , Bian Wenfeng , Liu Liwu , Li Qifeng , Fu Zijian , Liu Yanju , Leng Jinsong
Published: December 2021

Smart structures based on shape memory polymer composites (SMPCs) have attracted extensive attention because of their unique self-deployment behavior. This study investigated the thermal design and analysis of the SMPC flexible solar array system (SMPC-FSAS). The thermal design ensured the reliability of the deployment functionality and desirable structural temperatures. The fundamental properties of the shape-memory materials were obtained by dynamic mechanical analysis and shape fixity ratio tests. Thermal experiments, including the thermal balance test (TBT), thermal vacuum test and thermal cycle test were conducted to verify the safety and reliability of the SMPC-FSAS. Additionally, the temperature distribution of the SMPC-FSAS was simulated using numerical analysis. Notably, a geostationary satellite carrying the SMPC-FSAS was successfully launched into a geosynchronous orbit and controlled deployment was accomplished for the first time. The prediction of the numerical model was consistent with the TBT and on-orbit data, thus validating the accuracy of the numerical method. The research in this work has important reference significance for ultra-large SMPC-FSAS in the future.
Effective reduction of magnetisation losses in copper-plated multifilament coated conductors using spiral geometry
Authors: Amemiya Naoyuki , Shigemasa Mao , Takahashi Akira , Wang Ning , Sogabe Yusuke , Yamano Satoshi , Sakamoto Hisaki
Published: December 2021

We wound copper-plated multifilament coated conductors spirally on a round core to decouple filaments electromagnetically under ac transverse magnetic fields and measured their magnetisation losses. Although the coated conductors were plated with copper, which connects all filaments electrically and allows current sharing among them, the spiral geometry decoupled filaments similar to the twist geometry, and the magnetisation loss was reduced effectively by the multifilament structure. The measured magnetisation loss of a 4 mm wide, 10-filament coated conductor with a 20 μm thick copper wound spirally on a 3 mm core was only 7% of that of the same 10-filament coated conductor with a straight shape under an ac transverse magnetic field with an amplitude and frequency of 100 mT and 65.44 Hz, respectively. We separated the measured magnetisation losses into hysteresis and coupling losses and discussed the influence of filament width, copper thickness, and core diameter on both losses. We compared the hysteresis losses with the analytical values given by Brandt and Indenbom and compared the coupling losses with the values calculated using a general expression of coupling loss with the coupling time constants and geometry factors.
A visual and full-field method for detecting quench and normal zone propagation in HTS tapes
Authors: Wang Shudan , Guan Mingzhi , Chen Jiaxiang , Wang Xingzhe , Zhou Youhe
Published: December 2021

A fast and effective quench detection method is especially challenging in the development of high-field high-temperature superconducting (HTS) magnets for their safe operations and reliably releasing the stored energy during a quench. The occurrence and propagation of a quench are often accompanied by strong thermal and magneto-mechanical responses within superconducting magnets. Aiming to detect a quench in the whole process and capture the thermoelastic behavior associated with it, a new detection technique with a visual and full-field perception based on the digital image correlation (DIC) method is proposed in the present study. The experiment of a quench triggered thermally by a local spot heater is conducted for a YBCO coated conductor tape in a cryogenic chamber. The evolution and characteristics of the full-field strain in the HTS tape during the processes of a non-quench, a quench occurrence and quench propagation are intuitively presented with experimental observations. For the comparison purpose, the conventional quench detection methods by monitoring temperature and voltage signals during a quench are also utilized experimentally. The results verify the visual and full-field quench detection method, which uses a criterion of thermoelastic strain-rate for the quench occurrence and the evolution of strain contours for the normal zone propagating aspect. Additionally, a numerical quench model of coupled thermoelasticity to simulate the experiment is established and solved with the aid of Comsol multiphysics software. The quantitative results are in good agreement with the experimental measurements to prove the reliability and availability of the developed detection method. Since the DIC method is non-contact and insensitive to intense electromagnetic interferences, it is expected to provide a new technique on quench issues and some basic measurements on strain/stress behaviors in extreme environments of high-field HTS magnets in the future.
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

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

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

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

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

Optomechanical 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

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

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.
Multi-target ranging using an optical reservoir computing approach in the laterally coupled semiconductor lasers with self-feedback
Authors: Zhong Dong-Zhou , Xu Zhe , Hu Ya-Lan , Zhao Ke-Ke , Zhang Jin-Bo , Hou Peng , Deng Wan-An , Xi Jiang-Tao
Published: December 2021

We utilize three parallel reservoir computers using semiconductor lasers with optical feedback and light injection to model radar probe signals with delays. Three radar probe signals are generated by driving lasers constructed by a three-element laser array with self-feedback. The response lasers are implemented also by a three-element lase array with both delay-time feedback and optical injection, which are utilized as nonlinear nodes to realize the reservoirs. We show that each delayed radar probe signal can be predicted well and to synchronize with its corresponding trained reservoir, even when parameter mismatches exist between the response laser array and the driving laser array. Based on this, the three synchronous probe signals are utilized for ranging to three targets, respectively, using Hilbert transform. It is demonstrated that the relative errors for ranging can be very small and less than 0.6%. Our findings show that optical reservoir computing provides an effective way for applications of target ranging.
Spatio-spectral dynamics of soliton pulsation with breathing behavior in the anomalous dispersion fiber laser
Authors: Han Ying , Gao Bo , Huo Jiayu , Ma Chunyang , Wu Ge , Li Yingying , Chen Bingkun , Guo Yubin , Liu Lie
Published: December 2021

We have numerically and experimentally observed the soliton pulsation with obvious breathing behavior in the anomalous fiber laser mode-locked by a nonlinear polarization rotation technique. The numerical study of the soliton pulsation with breathing behavior was analyzed through the split-step Fourier method at first, and it was found that the phase difference caused by the polarization controller would affect the breathing characteristics. Then, taking advantage of the dispersive Fourier transform technique, we confirmed the breathing characteristic of soliton pulsation in the same fiber laser as the simulation model experimentally. These results complement the research on the breathing characteristic of soliton pulsation.
Design of an all-dielectric long-wave infrared wide-angle metalens
Authors: Zhang Ning , Li Qingzhi , Chen Jun , Tang Feng , Wu Jingjun , Ye Xin , Yang Liming
Published: December 2021

Optical metasurfaces are two-dimensional arrays of nano-scatterers that modify optical wavefronts at subwavelength spatial resolution. They achieve the effect of focusing through phase control under a subwavelength scale, and are called metalenses. They are poised to revolutionize optics by enabling complex low-cost systems. However, there are severe monochromatic aberrations in the metasurfaces. In this paper, the coma of the long-wave infrared optical system is eliminated through a single-layer metasurface. By changing the phase function, this metalens has a numerical aperture of 0.89, a focal length of 150 μm and a field of view of 120° (0.4@60 line pairs/mm) that enables diffraction-limited monochromatic imaging along the focal plane at a wavelength of 10.6 μm. The designed metasurface maintains a favorable value of the modulation transfer function at different angles. This equipment can be widely used in imaging and industrial processing.
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

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

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

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

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

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

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

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.
ARIMA Intervention Model for Measuring the Impact of the Lobster Seeds Fishing and Export Ban Policy on the Indonesian Lobster Export
Authors: Ilmiah Ria Dhotul , Oktora Siskarossa Ika
Published: December 2021

An intervention model is an analytical method for evaluating or measuring the impact of an external event called intervention, such as a natural disaster, holidays, sales promotions, and other policy changes. Two types of intervention variables will be used to represent the presence or absence of the event, i.e., a pulse or step. The pulse function is used to represent a temporary intervention, whereas the step function shows a long-term intervention. This study aims to develop a time series model with an intervention of step function for measuring the impact of two policies related to the prohibition of fishing and the export of lobster seeds on the export value of Indonesian lobster. These policies are the Ministerial Regulation No.1 of 2015 since January 2015 related banning of lobster seeds fishing (called first intervention) and the Ministerial Regulation No. 56 of 2016 since January 2017 related lobster seeds fishing and export ban policy (called second intervention). These regulations are designed to ensure lobster sustainability and add value to lobsters that are currently overfished. The results show that both policies significantly affect the export value of lobster in Indonesia, and the interventions have a permanent impact.
Stroke Classification Model using Logistic Regression
Authors: Annas S , Aswi A , Abdy M , Poerwanto B
Published: December 2021

This study aims to determine the factors that significantly affect the classification of stroke. The response variable used is the type of stroke, namely non-hemorrhagic stroke and hemorrhagic stroke. The predictors used were cholesterol level, blood sugar level, temperature, length of stay, pulse rate, and gender. By using logistic regression, the results obtained modeling accuracy of 74.8% where the predictors that have a significant effect (alpha <0.05) are total cholesterol and length of stay.
Exploration of Comparative Concepts in the Ethnomathematics of The Buton Traditional House
Authors: Kadir  , Salim  , Jafar
Published: December 2021

The Buton community has practiced mathematical culture in the form of a Buton traditional house called banua tadha (right house). The purpose of this study was to explore the comparative concepts in the ethnomathematics of the Buton traditional house. This research is qualitative research with an ethnographic approach. The results of this study indicate that every Buton traditional house contains several comparative concepts in the ethnomathematical: (1) the width of the door and the width of the stairs, (2) the walls of the house and the tutumbu, (3) the width of the house and tutumbu, (4) wall and pillar heights, (5) the height of the bhate and the length of the limana bathe, (6) the height of the front wall to the height of the side walls, (7) the width of the stair post with the size of the rungs of the stairs, and (8) wall height and house pole height, and (9) the shape of a right triangle formed by a crutch (konta), a pole (ariy), and a buffer (tadha). These comparisons can be used in learning mathematics to pass on the ethnomathematical local wisdom of the Buton traditional house.
Prediction of Forest Fire using Hybrid SOM-AdaBoost Method
Authors: Rosadi D , Andriyani W , Arisanty D , Agustina D
Published: December 2021

Prediction of the occurrences of forest fire has become interest of various research studies for instances, it is found that the hybrid method based on clustering using fuzzy c-means before doing the classification approach will improve the performance of prediction than directly apply the classification approach. In this study, we will consider the new hybrid approach between clustering based on Self Organizing Map (SOM) approach and classification using Boosting (AdaBoost) approach. Our empirical analysis shows using the same public data set, which has been used in several previous studies, the performance of hybrid SOM-AdaBoost will outperforms other methods in literatures.
Selection of Optimal Smoothing Parameters in Mixed Estimator of Kernel and Fourier Series in Semiparametric Regression
Authors: Ampa Andi Tenri , Nyoman Budiantara I , Zain Ismaini
Published: December 2021

In this article, we propose a new method of selecting smoothing parameters in semiparametric regression. This method is used in semiparametric regression estimation where the nonparametric component is partially approximated by multivariable Fourier Series and partly approached by multivariable Kernel. Selection of smoothing parameters using the method with Generalized Cross-Validation (GCV). To see the performance of this method, it is then applied to the data drinking water quality sourced from Regional Drinking Water Company (PDAM) Surabaya by using Fourier Series with trend and Gaussian Kernel. The results showed that this method contributed a good performance in selecting the optimal smoothing parameters.
Research on Melon Fruit Selection Based on Rank with YOLOv4 Algorithm
Authors: Budiarti Nur Azizah Eka , Wahjuni Sri , Suwarno Willy Bayuardi , Wulandari
Published: December 2021

Melon is one of the most popular fruits that is exceptionally favoured in Indonesia because it can be consumed directly as fresh fruit or processed as juice or salad. To meet the national market demand, several technologies are used to increase production, one of which is fruit selection. Plants need to be pruned based on fruit size so that fruit quality is maintained. One of the new approaches to detect plant fruits is using deep convolutional neural networks. The goal is to build a melon fruit detection system based on fruit size ranking for selection reliability. Recent work in deep neural networks has developed an excellent object detector, namely the one-stage You Only Look Once (YOLO) algorithm. We used the YOLOv4 model, the fourth generation of YOLO with speed acceleration and detection accuracy better than the previous versions. In addition, eight model schemes were tested with three different hyper-parameters: batch size, iterations, and learning rate. It was found that Scheme G using batch size 64, iterations 2000, and learning rate 0.001 obtained the highest score for both F1-score and mAP with values of 84.47% and 87.68%, respectively. It can be said that the F1-score value is directly proportional to the mAP value.
Combination of ADASYN-N and Random Forest in Predicting of Obesity Status in Indonesia: A Case Study of Indonesian Basic Health Research 2013
Authors: Aqsha M , Thamrin SA , Lawi Armin
Published: December 2021

Obesity is a pathological condition due to the accumulation of excessive fat needed for body functions. The risk factors for obesity are related to their obesity status. Various machine learning approaches are an alternative in predicting obesity status. However, in most cases, the available datasets are not sufficiently balanced in their data classes. The existence of data imbalances can cause the prediction results to be inaccurate. The purpose of this paper is to overcome the problem of data class imbalance and predict obesity status using the 2013 Indonesian Basic Health Research (RISKESDAS) data. Adaptive Synthetic Nominal (ADASYN-N) can be used to balance obesity status data. The balanced obesity status data is then predicted using one of the machine learning approaches, namely Random Forest. The results obtained show that through ADASYN-N with a balance level parameter of 1 (β = 100%) after synthetic data generation and Random Forest with a tree number of 200 and involving 7 variables as risk factors, giving the results of the classification of obesity status which is good. This can be seen from the AUC value of 84.41%.
Validation and Implementation of Hawgent on Pythagoras Theorem
Authors: Li Xinxin , Zhou Ying , Chen Mingliang
Published: December 2021

Math lessons are abstract and complex for students to understand, so that the teachers need instructional media to develop by using technology to help their students get deep learning. This study aimed to validate the instructional media to teach the Pythagorean theorem and describe the students and the teachers’ responses to the instructional media. The researchers implemented the ADDIE model in this study. The sample comprised 30 students in 7th grade and 56 teachers. The process of validation involved ten academics. The results of this study showed that the instructional material could be used. The results also showed that the students were happier when the teachers used the instructional media in the classroom.
Language Constraints in Constructing Arguments for Mathematical Proofs
Authors: Minggi I , Alimuddin  , Sabri
Published: December 2021

A learning trajectory for constructing mathematical proof has been developed. The trajectory is to provide the students with a step-by-step procedure in constructing arguments for proving mathematical statements. However, in proving activities, the students were found to encounter difficulties in completing a deductive axiomatic argument constituting an accepted mathematical proof. An investigation has been conducted to explore the problems the students experienced in constructing proofs. It was found that they faced language constraints in constructing mathematical arguments. They encountered challenges in how to correctly express the mathematical statements in their constructed proofs.
Measurements of the local temperature correlation time in a turbulent flame using coherent anti-Stokes Raman spectroscopy
Authors: Kobtsev VD , Kozlov D N , Kostritsa S A , Orlov S N , Smirnov V V , Volkov S Yu
Published: December 2021

The feasibility to determine the timescale of pulsations of “instantaneous” local temperatures in a turbulent flame at a microsecond time scale by using coherent anti-Stokes Raman scattering (CARS) spectroscopy is demonstrated for the first time to our knowledge. A laboratory laser measurement complex was utilized, based on two CARS-spectrometers employing synchronized pulse-repetitive lasers with 10 ns pulse duration. The system enabled to record, with high temporal resolution (in one single laser shot) and at a variable delay between two sequential shots following each other in pairs at a repetition rate of 10 Hz, series of CARS spectra of N2 molecules from a probe volume as small as 0.03×0.03×2 mm3. From the spectra, “instantaneous” temperatures at a given delay were derived. The obtained values enabled calculation of the correlation coefficient of temperature pulsations vs the delay. The results are presented for the series of 500 single-shot coupled measurements, at the delays in the range 1 μs – 0 ms, of local gas temperatures in a few points of an open turbulent partially premixed methane-air flame of a model burner with visually distinguishable stability of combustion. The average temperatures were between 1500 K and 1800 K. The measurements allowed temperature correlation times in the selected points of the flame to be derived.
Investigation of the bag-breakup phenomena of the spray generation processes during wind-wave interaction in the laboratory experiments with optical methods
Authors: Kandaurov A A , Sergeev D A , Troitskaya Yu I
Published: December 2021

Present paper devoted to the investigations with optical methods processes of artificially induced bag-breakup type of spray formation phenomenon within wind-wave interaction. Experiments were carried out on the Thermostratified Wind-Wave Tank of the IAP RAS. High-speed video filming with the shadow imaging method demonstrated that it was possible to artificially reproduce all the main stages of this phenomenon, which are also observed for the sporadically occurred ones: inflation of a thin membrane surrounded by a thicker rim, rupture of the membrane leading to the formation of small droplets, fragmentation of the rim with the formation of large droplets. Special processing of the images allowed us to estimate typical lifetimes and sizes of membrane for artificial bag-breakup events which turned out to be close to the same parameters for sporadically occurred ones.
Processing of two-dimensional velocity fields for reconstructing three-dimensional flow patterns
Authors: Yu Belov S
Published: December 2021

The paper is concerned with the obtaining three-dimensional velocity fields of a gas or liquid flow based on the available cross-sections of this flow. The descriptions of the main optical methods for studying flows are designed to construct a cross-section of the observed process, but it would be much more informative to obtain information in the visualization not in the cross-section of a volume, but in this volume itself. The paper deals with obtaining three-dimensional flow velocity fields using various approximation methods. The method of estimating the most suitable approximating function is also given. The determination of the optimal type of approximation for the reconstruction of the three-dimensional velocity field was tested on an artificially created vortex.
Aberration analysis of AOTF-based stereoscopic spectral imager using optical design software
Authors: Batshev VI , Gorevoy A V , Pozhar V E , Machikhin A S
Published: December 2021

Stereoscopic spectral imagers using acousto-optic tunable filters (AOTF) provide high-resolution narrow band images acquired from two viewpoints with different polarization in arbitrary spectral intervals, which allows obtaining three-dimensional hyperspectral models of inspected objects for many applications. We discuss modeling of acousto-optic (AO) cell for optical system design and introduce a program module for ray tracing through AO cell compatible with Zemax optical design software. A detailed study of the optical aberrations that limit the image quality in two AOTF-based stereoscopic systems implementing simultaneous AO diffraction of two differently polarized beams in single AO cell is presented. This approach may be used to design various AOTF-based imaging systems, but the limitations of ray tracing analysis should be considered.
Methodology for assessing the uncertainty of measurements of mechanical stresses by the ultrasonic method with the help of an optical-acoustic separate-combined transducer
Authors: Fedorov A V , Bychenok V A , Berkutov I V , Alifanova I E , Khoshev A E
Published: December 2021

The work is devoted to the ultrasonic method of controlling mechanical stresses using ultrasonic head waves. The factors that contribute to the result of measurements of mechanical stresses include: the propagation velocity of the head ultrasonic wave, the temperature of the environment and the object of control, the coefficients of acoustoelastic and thermoacoustic coupling, parameters of the optical-acoustic transducer. The contribution of each of these factors to the results of measurements of mechanical stresses is assessed. A technique for assessing the uncertainty of measurements of mechanical stresses by the ultrasonic method using head waves has been developed.
Spectral analysis of the photoconductivity for characterization of CdTe И CdZnTe detectors
Authors: Gazizov I M , Smirnov A A
Published: December 2021

The results of the application of optical methods are considered: spectral analysis of photoconductivity in the range 400–1800 nm and field measurements of stationar photoconductivity to study the bulk and surface characteristics of CdTe and CdZnTe gamma-ray detectors. The studies of the photoresponse of the samples were carried out in different irradiation modes: modulated at a frequency of 25 Hz and a constant light flux. The measurements were carried out at room temperature on domestic and foreign materials of detector quality. Using the spectral photoconductivity method, the parameters of deep levels, which affect the detector properties, have been estimated in the studied materials. Based on the calculations of the field dependences of the photoconductivity, the volume and surface parameters of the capture and recombination of non-equilibrium carriers in the investigated detectors were determined. The results of calculating the transport characteristics of charge transfer by electrons μτe in detectors are compared with similar parameters measured using the traditional method of irradiating the detector with alpha particles. To measure the band gap in CdTe and CdZnTe at room temperature the method was modified for calculating ΔEg. The possibility of monitoring the Zn content in CdZnTe detectors using the spectral photoconductivity method is shown.