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On systematic development of FSI solvers in the context of particle methods

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Journal of Hydrodynamics 2022年第3期34卷 395-407页

作者： Abbas Khayyer Hitoshi Gotoh yuma Shimizu Department of Civil and Earth Resources Engineering Kyoto UniversityKyotoJapan

This paper presents a review on state-of-the-art of developments corresponding to fluid-structure interaction(FSI)solvers developed within the context of particle *** paper reviews and highlights the potential robustness of entirely Lagrangian meshfree FSI solvers in reproducing FSI corresponding to extreme events and portrays the future perspectives for systematic developments towards reliable engineering applications with respect to rapid advances in technology and emergence of so-called advanced materials that can result in complex and highly non-linear structural ***,the paper highlights the necessity for reproduction of comprehensive structural responses,including viscoelastic,elastoplastic and progressive damages/failures,by the advanced FSI solvers developed within the context of particle *** this regard,extensions of the structure model are suggested to be conducted in a variationally consistent framework to ensure stability,accuracy and physical reliability including thermodynamic *** paper reviews basics of mathematical and numerical modelling for entirely Lagrangian meshfree hydroelastic FSI solvers and presents a brief background on extensions of such solvers towards reproducing viscoelastic structural *** preliminary numerical results on structural viscoelasticity achieved by an extended Hamiltonian SPH(HSPH)model are *** vision paper also concisely portrays the future perspectives for systematic development of particle-based FSI solvers.

关键词： Fluid-structure interaction(FSI) entirely Lagrangian meshfree smoothed particle hydrodynamics(SPH) Hamiltonian SPH(HSPH) viscoelasticity

Cobalt-based magnetic Weyl semimetals with high-thermodynamic stabilities

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npj Computational Materials 2021年第1期7卷 41-48页

作者： Wei Luo yuma Nakamura Jinseon Park Mina Yoon Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTN 37831USA Department of Physics and Astronomy University of TennesseeKnoxvilleTN 37916USA

Recent experiments identified Co_(3)Sn_(2)S_(2) as the first magnetic Weyl semimetal(MWSM).Using first-principles calculation with a global optimization approach,we explore the structural stabilities and topological electronic properties of cobalt(Co)-based shandite and alloys,Co_(3)MM’X_(2)(M/M’=Ge,Sn,Pb,X=S,Se,Te),and identify stable structures with different Weyl *** a tight-binding model,for the first time,we reveal that the physical origin of the nodal lines of a Co-based shandite structure is the interlayer coupling between Co atoms in different Kagome layers,while the number of Weyl points and their types are mainly governed by the interaction between Co and the metal atoms,Sn,Ge,and *** Co_(3)SnPbS_(2) alloy exhibits two distinguished topological phases,depending on the relative positions of the Sn and Pb atoms:a three-dimensional quantum anomalous Hall metal,and a MWSM phase with anomalous Hall conductivity(~1290Ω^(−1) cm^(−1))that is larger than that of Co_(2)Sn_(2)S_(2).Our work reveals the physical mechanism of the origination of Weyl fermions in Co-based shandite structures and proposes topological quantum states with high thermal stability.

关键词： stability alloy magnetic

Towards development of enhanced fully-Lagrangian mesh-free computational methods for fluid-structure interaction

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Journal of Hydrodynamics 2018年第1期30卷 49-61页

作者： Abbas Khayyer Hitoshi Gotoh Hosein Falahaty yuma Shimizu Department of Civil and Earth Resources Engineering Kyoto UniversityKatsura Campus

Simulation of incompressible fluid flow-elastic structure interactions is targeted by using fully-Lagrangian mesh-free computational methods. A projection-based fluid model（moving particle semi-implicit（MPS）） is coupled with either a Newtonian or a Hamiltonian Lagrangian structure model（MPS or HMPS） in a mathematically-physically consistent manner. The fluid model is founded on the solution of Navier-Stokes and continuity equations. The structure models are configured either in the framework of Newtonian mechanics on the basis of conservation of linear and angular momenta, or Hamiltonian mechanics on the basis of variational principle for incompressible elastodynamics. A set of enhanced schemes are incorporated for projection-based fluid model（Enhanced MPS）, thus, the developed coupled solvers for fluid structure interaction（FSI） are referred to as Enhanced MPS-MPS and Enhanced MPS-HMPS. Besides, two smoothed particle hydrodynamics（SPH）-based FSI solvers, being developed by the authors, are considered and their potential applicability and comparable performance are briefly discussed in comparison with MPS-based FSI solvers. The SPH-based FSI solvers are established through coupling of projection-based incompressible SPH（ISPH） fluid model and SPH-based Newtonian/Hamiltonian structure models, leading to Enhanced ISPH-SPH and Enhanced ISPH-HSPH. A comparative study is carried out on the performances of the FSI solvers through a set of benchmark tests, including hydrostatic water column on an elastic plate,high speed impact of an elastic aluminum beam, hydroelastic slamming of a marine panel and dam break with elastic gate.

关键词： Fluid structure interaction(FSI) projection-based method moving particle semi-implicit incompressible smoothed particle hydrodynamics(ISPH) Hamiltonian MPS(HMPS) Hamiltonian SPH(HSPH)

Comparison of dissimilarity measures for cluster analysis of X-ray diffraction data from combinatorial libraries

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npj Computational Materials 2017年第1期3卷 448-456页

作者： yuma Iwasaki A.Gilad Kusne Ichiro Takeuchi IoT Devices Research Laboratories NEC CorporationTsukuba 305-8501Japan Spin Quantum Rectification Project ERATOJapan Science and Technology AgencySendai 980-8577Japan National Institute of Standards and Technology GaithersburgMD 20899USA Department of Materials Science and Engineering University of MarylandCollege parkMD 20742USA

Machine learning techniques have proven invaluable to manage the ever growing volume of materials research data produced as developments continue in high-throughput materials simulation,fabrication,and *** particular,machine learning techniques have been demonstrated for their utility in rapidly and automatically identifying potential composition-phase maps from structural data characterization of composition spread libraries,enabling rapid materials fabrication-structure-property analysis and functional materials discovery.A key issue in development of an automated phase-diagram determination method is the choice of dissimilarity measure,or kernel *** desired measure reduces the impact of confounding structural data issues on analysis *** issues include peak height changes and peak shifting due to lattice constant change as a function of *** this work,we investigate the choice of dissimilarity measure in X-ray diffraction-based structure analysis and the choice of measure’s performance impact on automatic composition-phase map *** dissimilarity measures are investigated for their impact in analyzing X-ray diffraction patterns for a Fe-Co-Ni ternary alloy composition *** cosine,Pearson correlation coefficient,and Jensen-Shannon divergence measures are shown to provide the best performance in the presence of peak height change and peak shifting(due to lattice constant change)when the magnitude of peak shifting is *** prior knowledge of the maximum peak shifting,dynamic time warping in a normalized constrained mode provides the best *** work also serves to demonstrate a strategy for rapid analysis of a large number of X-ray diffraction patterns in general beyond data from combinatorial libraries.

关键词： alloy shifting analysis

Incompressible SPH simulation of solitary wave propagation on permeable beaches

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Journal of Hydrodynamics 2020年第4期32卷 664-671页

作者： Chiaki Tsurudome Dongfang Liang yuma Shimizu Abbas Khayyer Hitoshi Gotoh Department of Engineering University of CambridgeTrumpington StreetCambridgeUK Graduate School of Engineering Kyoto UniversityKyotoJapan

Wave propagation on uniformly sloped beaches is a canonical coastal engineering topic that has been studied extensively in the past few ***,most of these studies treat beaches as solid boundaries even though they are often made of porous materials,such as sediment and *** beaches struck by tsunami-like waves have not been adequately *** is expected that the degree of penneability plays a crucial role in mitigating the impact of the *** study examines solitary wave run-ups on sandy beaches using an incompressible smoothed particle hydrodynamics(ISPH)*** permeability of the beach is considered to be directly related to the diameter of its constituent sand *** obtain a satisfactory pressure field,which cannot be achieved using the original ISPH algorithm,the source term of the pressure Poisson equation has been modified based on a higher-order source-term *** within the porous medium are computed in the same framework as those outside the porous *** the current model,no transition zone is needed at the boundary of the porous *** wave-attenuation effect of the porous medium is discussed,with a particular focus on the relationship between the mn-up height and grainsize.

关键词： Solitary wave porosity incompressible smoothed particle hydrodynamics(ISPH) run-up

Organelle genome assembly uncovers the dynamic genome reorganization and cytoplasmic male sterility associated genes in tomato

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Horticulture Research 2021年第1期8卷 3464-3474页

作者： Kosuke Kuwabara Issei Harada yuma Matsuzawa Tohru Ariizumi Kenta Shirasawa Graduate School of Life and Environmental Sciences University of TsukubaTsukubaIbaraki 305-8577Japan TOKITA Seed Co.LTD. KazoSaitama 349-1144Japan Tsukuba Plant Innovation Research Center TsukubaIbaraki 305-8577Japan Kazusa DNA Research Institute KisarazuChiba 292-0818Japan

To identify cytoplasmic male sterility(CMS)-associated genes in tomato,we determined the genome sequences of mitochondria and chloroplasts in three CMS tomato lines derived from independent asymmetric cell fusions,their nuclear and cytoplasmic donors,and male fertile weedy cultivated tomato and wild *** structures of the CMS mitochondrial genomes were highly divergent from those of the nuclear and cytoplasmic donors,and genes of the donors were mixed up in these *** the other hand,the structures of CMS chloroplast genomes were moderately conserved across the donors,but CMS chloroplast genes were unexpectedly likely derived from the nuclear *** analysis of the structures and contents of organelle genes and transcriptome analysis identified three genes that were uniquely present in the CMS lines,but not in the donor or fertile ***-sequencing analysis indicated that these three genes transcriptionally expressed in anther,and identified different RNA editing levels in one gene,orf265,that was partially similar to ATP synthase subunit 8,between fertile and sterile *** orf265 was a highly potential candidate for CMS-associated *** study suggests that organelle reorganization mechanisms after cell fusion events differ between mitochondria and chloroplasts,and provides insight into the development of new F1 hybrid breeding programs employing the CMS system in tomato.

关键词： breeding sterile donor

Plasma brain natriuretic peptide level in older outpatients with heart failure is associated with physical frailty, especially with the slowness domain

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Journal of Geriatric Cardiology 2016年第7期13卷 608-614页

作者： Shu Nishiguchi yuma Nozaki Masayuki Yamaji Kanako Oya Yuki Hikita Tomoki Aoyama Hiroshi Mabuchi Department of Physical Therapy School of Health Sciences Tokyo University of Technology Tokyo Japan Department of Physical Therapy Human Health Sciences Graduate School of Medicine Kyoto University Kyoto Japan Department of Cardiovascular Medicine Koto Memorial Hospital Shiga Japan Department of Rehabilitation Unit Koto Memorial Hospital Shiga Japan

Objective To determine the association between plasma brain natriuretic peptide （BNP） level in patients with heart failure （HF） and physical frailty as well as with each domain of physical frailty. Methods Two hundred and six outpatients of cardiovascular medicine aged 60 years and older who had been hospitalized for HF or had been given a prescription medication for HF were included. Physical frailty was assessed using the following five domains： slowness, weakness, exhaustion, low activity, and shrinking, according to the Cardiovascular Health Study. Patients were divided into nonfi-ailty and frailty groups according to frailty scores. Plasma BNP level was measured. The 6-min walk test was performed to measure endurance. Results Plasma BNP was significantly different between the two groups （frailty group： 158.0 i 214.7 pg/mL, nonfrailty group： 65.2 ~ 88.0 pg/mL, P 〈 0.01）. Multivariate logistic regression analysis revealed log-transformed plasma BNP （Log BNP） was significantly associated with physical frailty （OR： 1.68, 95% CI： 1.11-2.56）, and Log BNP was significantly associated with the slowness domain （walking speed 〈 1.0 m/s） of physical frailty （OR： 1.75, 95% Ch 1.15-2.67）. Additionally, Log BNP was negatively correlated to the 6-minute walk distance （6MWD）（p=0.37, P 〈 0.01）, while 6MWD was positively correlated to walking speed （p = 0.66, P 〈 0.01）. Conclusions Plasma BNP level was related to physical frailty, especially in the slowness domain. Endurance may intervene in the associations between plasma BNP level and walking speed.

关键词： Brain natriuretic peptide Heart failure Physical frailty Walking speed

Identification of advanced spin-driven thermoelectric materials via interpretable machine learning

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npj Computational Materials 2019年第1期5卷 232-237页

作者： yuma Iwasaki Ryohto Sawada Valentin Stanev Masahiko Ishida Akihiro Kirihara Yasutomo Omori Hiroko Someya Ichiro Takeuchi Eiji Saitoh Shinichi Yorozu Central Research Laboratories NEC CorporationTsukuba 305-8501Japan PREST JSTSaitama 322-0012Japan Department of Materials Science and Engineering University of MarylandCollege ParkMD 20742USA Center for Nanophysics and Advanced Materials University of MarylandCollege ParkMD 20742USA Joint Quantum Institute University of MarylandCollege ParkMD 20742USA Institute for Materials Research Tohoku UniversitySendai 908-8577Japan WPI Advanced Institute for Materials Research Tohoku UniversitySendai 908-8577Japan Advanced Science Research Center Japan Atomic Energy AgencyTokai 319-1195Japan RIKEN Center for Emergent Matter Science Wako 351-0198Japan

Machine learning is becoming a valuable tool for scientific *** attractive is the application of machine learning methods to the field of materials development,which enables innovations by discovering new and better functional *** apply machine learning to actual materials development,close collaboration between scientists and machine learning tools is ***,such collaboration has been so far impeded by the black box nature of many machine learning *** is often difficult for scientists to interpret the data-driven models from the viewpoint of material science and ***,we demonstrate the development of spin-driven thermoelectric materials with anomalous Nernst effect by using an interpretable machine learning method called factorized asymptotic Bayesian inference hierarchical mixture of experts(FAB/HMEs).Based on prior knowledge of material science and physics,we were able to extract from the interpretable machine learning some surprising correlations and new knowledge about spin-driven thermoelectric *** by this,we carried out an actual material synthesis that led to the identification of a novel spin-driven thermoelectric *** material shows the largest thermopower to date.

关键词： becoming learning attractive

Fabrication of Porous SiO_2·RO/SUS Composite Body for DPF (Diesel Particulate Filter) and Microwave Heating Behavior

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Journal of Iron and Steel Research International 2012年第S2期19卷 787-791页

作者： LEE Chang Chuan ICHIHASHI yuma YOSHIKAWA Noboru TANIGUCHI Shoji Graduate School of Environmental Studies Tohoku University School of Manufacturing Engineering Universiti Malaysia Perlis Department of Materials Science and Engineering Tohoku University

Glass/stainless steel porous composite body were prepared by the polyurethane sponge replica method using slurries containing mixture of SiO_2-RO/30 vol%*** porous samples were obtained which consists of well-distributed stainless steel particles within the glass *** a microstructure is desired for the purpose as a soot particulate filters(DPF)utilizing microwave rapid heating in cold start *** ability of the fabricated porous composite body was carried out placing the specimen in the maximum H-field of a 2.45 GHz single mode applicator. Heating behavior of the samples was mainly influenced by the volume fraction of stainless *** heating rate was observed for samples with higher stainless steel *** to the different microwave absorbability of the materials, stainless steel particle in the porous matrix structure was firstly heated up by microwave and transferred the heat energy throughout the whole *** of the fraction of the stainless steel particle in the matrix structure led the better heating;however the strength of the samples decreased.

关键词： porous composite polyurethane sponge microwave heating