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Chebyshev polynomial-based Ritz method for thermal buckling and free vibration behaviors of metal foam beams

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 891-910页

作者： n.d.nGUYEn T.n.nGUYEn faculty of Civil Engineering Ho Chi Minh City University of Technology and EducationHo Chi Minh City 71309Viet Nam faculty of Engineering and Technology Kien Giang UniversityChau Thanh 92000Viet Nam

This study presents the Chebyshev polynomials-based Ritz method to examine the thermal buckling and free vibration characteristics of metal foam *** analyses include three models for porosity distribution and two scenarios for thermal *** material properties are assessed under two conditions,i.e.,temperature dependence and temperature *** theoretical framework for the beams is based on the higher-order shear deformation theory,which incorporates shear deformations with higher-order *** governing equations are established from the Lagrange equations,and the beam displacement fields are approximated by the Chebyshev *** simulations are performed to evaluate the effects of thermal load,slenderness,boundary condition(BC),and porosity distribution on the buckling and vibration behaviors of metal foam *** findings highlight the significant influence of temperature-dependent(Td)material properties on metal foam beams'buckling and vibration responses.

关键词： Ritz method Chebyshev function buckling vibration metal foam beam higher-order beam theory(HOBT)

Influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 563-580页

作者： n.HUMnEKAR d.SRInIVASACHARYA department of Mathematics National Institute of TechnologyWarangal 506004TelanganaIndia

The influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel is *** darcyBrinkman model is used to characterize the fluid flow dynamics in porous *** analytical solutions are obtained for the unidirectional and completely developed *** on a normal mode analysis,the generalized eigenvalue problem under a perturbed state is *** eigenvalue problem is then solved by the spectral ***,the critical Rayleigh number with the corresponding wavenumber is evaluated at the assigned values of the other flow-governing *** results show that increasing the darcy number,the Lewis number,the dufour parameter,or the Soret parameter increases the stability of the system,whereas increasing the inclination angle of the channel destabilizes the ***,the flow is the most unstable when the channel is vertically oriented.

关键词： nanofluid inclined channel variable viscosity linear stability double dif-fusion porous medium

Localized-states quantum confinement induced by roughness in CdMnTe/CdTe heterostructures grown on Si(111) substrates

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Journal of Semiconductors 2024年第9期45卷 28-35页

作者： Leonarde n.Rodrigues Wesley f.Inoch Marcos L.f.Gomes Odilon d.d.Couto Jr. Bráulio S.Archanjo Sukarno O.ferreira Physics department Federal University of ViçosaViçosa36570-900Minas GeraisBrazil Instituto de física Gleb Wataghin Universidade Estadual de CampinasCampinas13083-859São PauloBrazil national Institute of Metrology Quality and Technology(Inmetro) Materials Metrology Division(DIMAT)Xerém2525-020Rio de JaneiroBrazil

This work shows that despite a lattice mismatch of almost 20%, CdMnTe/CdTe/CdMnTe heterostructures grown directly on Si(111) have surprisingly good optical emission properties. The investigated structures were grown by molecular beam epitaxy and characterized by scanning transmission electron microscopy, macro-and micro-photoluminescence. Low temperature macro-photoluminescence experiments indicate three emission bands which depend on the CdTe layer thickness and have different confinement characteristics. Temperature measurements reveal that the lower energy emission band (at 1.48 eV)is associated to defects and bound exciton states, while the main emission at 1.61 eV has a weak 2d character and the higher energy one at 1.71 eV has a well-defined (zero-dimensional, 0d) 0d nature. Micro-photoluminescence measurements show the existence of sharp and strongly circularly polarized (up to 40%) emission lines which can be related to the presence of Mn in the heterostructure. This result opens the possibility of producing photon sources with the typical spin control of the diluted magnetic semiconductors using the low-cost silicon technology.

关键词： CdMnTe/CdTe/CdMnTe heterostructure CdTe/CdMnTe quantum emitters quantum dot-like emission silicon(111)substrate

design of a novel Exoskeleton with Passive Magnetic Spring Self-locking and Spine Lateral Balancing

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Journal of Bionic Engineering 2024年第1期21卷 236-255页

作者： Jhon f.Rodríguez-León Betsy d.M.Chaparro-Rico daniele Cafolla francesco Lago Eduardo Castillo-Castañeda Giuseppe Carbone Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada Unidad Querétaro MecatronicaInstituto Politécnico NacionalCerro Blanco 14176090 Colinas del CimatarioQuerétaroMexico department of Mechanical Energy and Management EngineeringUniversity of CalabriaVia P.Bucci Cubo 46 C87036 RendeItaly faculty of Science and Engineering Department of Computer ScienceSwansea UniversitySwanseaUK CESTER University of Cluj-NapocaCluj-NapocaRomania

This paper proposes a new upper-limb exoskeleton to reduce worker physical *** proposed design is based on a novel PRRRP(P-Prismatic;R-Revolute)kinematic chain with 5 passive degrees of freedom(dof).Utilizing a magnetic spring,the proposed mechanism includes a specially designed locking mechanism that maintains any desired task *** proposed exoskeleton incorporates a balancing mechanism to alleviate discomfort and spinal torsional effects also helping in limb weight *** paper reports specific models and simulations to demonstrate the feasibility and effectiveness of the proposed *** experimental characterization is performed to validate the performance of the mechanism in terms of forces and physical strain during a specific application consisting of ceiling-surface drilling *** obtained results preliminarily validate the engineering feasibility and effectiveness of the proposed exoskeleton in the intended operation task thereby requiring the user to exert significantly less force than when not wearing it.

关键词： Assistive mechanism Exoskeleton Locking mechanism Bionic robot

Ion heat transport in electron cyclotron resonance heated L-mode plasma on the T-10 tokamak

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Plasma Science and Technology 2024年第4期26卷 52-60页

作者： V.A.KRUPIn M.R.nURGALIEV A.R.nEMETS I.A.ZEMTSOV S.d.SUnTSOV T.B.MYALTOn d.S.SERGEEV n.A.SOLOVEV d.V.SARYCHEV d.V.RYJAKOV S.n.TUGARInOV n.n.nAUMEnKO national Research Centre“Kurchatov Institute” Moscow 123182Russia Bauman Moscow State Technical University Moscow 105005Russia Institution“Project Center ITER” Moscow 123098Russia JSC“SOLAR” Minsk 220034Belarus

Anomalous ion heat transport is analyzed in the T-10 tokamak plasma heated with electron cyclotron resonance heating(ECRH) in second-harmonic extra-ordinary mode. Predictive modeling with empirical scaling for Ohmical heat conductivity shows that in ECRH plasmas the calculated ion temperature could be overestimated, so an increase of anomalous ion heat transport is required. To study this effect two scans are presented: over the EC resonance position and over the ECRH power. The EC resonance position varies from the high-field side to the low-field side by variation of the toroidal magnetic field. The scan over the heating power is presented with on-axis and mixed ECRH regimes. discharges with high anomalous ion heat transport are obtained in all considered regimes. In these discharges the power balance ion heat conductivity exceeds the neoclassical level by up to 10 times. The high ion heat transport regimes are distinguished by three parameters: the ratio Te/Ti, the normalized electron density gradient R/■, and the ion–ion collisionality νii~*. The combination of high Te/Ti, high νii~*, and R/■=6-10 results in values of normalized anomalous ion heat fluxes up to 10 times higher than in the low transport scenario.

关键词： tokamak L-mode electron cyclotron resonance heating ion heat transport

Are we ready to use new endoscopic scores for ulcerative colitis?

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World Journal of Gastroenterology 2024年第10期30卷 1466-1469页

作者： Rodrigo Quera Paulina núñez f Universidad de los Andes Inflammatory Bowel Disease ProgramClinica Universidad de los AndesDigestive Disease CenterSantiago 7600976RMChile digestive disease Center Inflammatory Bowel Disease ProgramClínica Universidad de los AndesSantiago 7620157Chile department of Gastroenterology Universidad de Chile-Hospital San Juan de DiosSantiago 770123Chile

for ulcerative colitis(UC),the variability in inflammatory activity along the colon poses a challenge in *** focus on achieving endoscopic healing in UC is evident,where the UC Endoscopic Index of Severity and Mayo Endoscopic Subscore are commonly used for ***,these indices primarily consider the most severely affected *** et al recent study validates the Toronto Inflammatory Bowel disease Global Endoscopic Reporting(TIGER)score offering a comprehensive assessment of inflammatory activity across diverse segments of the colon and rectum and a reliable index correlating strongly with UC Endoscopic Index of Severity and moderately with Mayo Endoscopic Subscore(MES).despite recommendation,certain aspects warrant further *** calprotectin,an intermediate target,correlates with TIGER and should be *** TIGER scores defining endoscopic remission and response,evaluating agreement with histological activity,and assessing inter-endoscopist agreement for TIGER require *** the correlation between TIGER and intestinal ultrasound,akin to MES,adds value.

关键词： Ulcerative colitis Sigmoidoscopy Colonoscopy Score index

Omics-based biomarkers as useful tools in metabolic dysfunctionassociated steatotic liver disease clinical practice:How far are we?

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World Journal of Gastroenterology 2024年第14期30卷 1982-1989页

作者： Julieta Trinks María f Mascardi Adrián Gadano Sebastián Marciano Instituto de Medicina Traslacional e Ingeniería Biomédica-Consejo nacional de Investigaciones Científicas y Técnicas-Instituto Universitario del Hospital Italiano-Hospital Italiano de Buenos Aires Ciudad Autónoma de Buenos Aires C1199ACLArgentina Consejo nacional de Investigaciones Científicas y Técnicas Ciudad Autónoma de Buenos Aires C1425FQBArgentina Liver Unit Hospital Italiano de Buenos AiresCiudad Autónoma de Buenos Aires C1199DFArgentina department of Research Hospital Italiano de Buenos AiresCiudad Autónoma de Buenos Aires C1199DFArgentina

Unmet needs exist in metabolic dysfunction-associated steatotic liver disease(MASLd)risk *** ability to identify patients with MASLd with advanced fibrosis and at higher risk for adverse outcomes is still *** novel biomarkers could represent a meaningful improvement to current risk *** this aim,omics technologies have revolutionized the process of MASLd biomarker discovery over the past *** the research in this field is thriving,much of the publication has been haphazard,often using single-omics data and specimen sets of convenience,with many identified candidate biomarkers but lacking clinical validation and *** we incorporate these biomarkers to direct patients’management,it should be considered that the roadmap for translating a newly discovered omics-based signature to an actual,analytically valid test useful in MASLd clinical practice is rigorous and,therefore,not easily *** article presents an overview of this area’s current state,the conceivable opportunities and challenges of omics-based laboratory diagnostics,and a roadmap for improving MASLd biomarker research.

关键词： Metabolic dysfunction-associated steatotic liver disease non-alcoholic steatohepatitis Biomarker Risk stratification Omics

Effects of synthesis parameters on the performance of crosslinked Co-polymers with clays for conformance control

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Petroleum Research 2024年第1期9卷 98-108页

作者： A.A.Roslan n.A.A.Aziz n.f.A.deraman I.dzulkarnain Petroleum Engineering department Centre of Research Enhanced Oil Recovery(COREOR)Universiti Teknologi PETRONASSeri IskandarPerakMalaysia Chemical Engineering department Centre of Research Enhanced Oil Recovery(COREOR)Universiti Teknologi PETRONASSeri IskandarPerakMalaysia

Conformance control or water shut-off is a technique used to improve oil *** conformance control,polymers block high permeability water areas and redistribute water drive toward unswept oil *** this study,co-polymers(denoted ATP-PGV/AM-co-AMPS)were synthesized using acrylamide(AM)and 2-acrylamide-2-methylpropane sulfonic acid(AMPS)as the monomers,polyethylene glycol(PEG)-200 and methylenebisacrylamide(MBA)as the crosslinkers,attapulgite(ATP)and bentonite(PGV)as the clay types,and ammonium persulfate(APS)as the initiator,in addition to paraffin oil and *** were synthesized using inverse emulsion polymerization with different concentrations of monomers,crosslinkers,and clays,and they were characterized using fourier-transform infrared(fTIR)spectroscopy and scanning electron microscopy(SEM)with energy dispersive X-ray spectroscopy(EdX).fTIR spectra of the samples confirmed the existence of sulfonate and hydroxyl groups,which are important for polymer ***-EdX images indicated that the morphology and elemental composition were different before and after swelling,confirming the occurrence of ***,samples were placed in sodium chloride solution(20,000 ppm)for 7 days to evaluate swelling at both room temperature and 90°*** analysis(TGA)and differential scanning calorimetry(dSC)were used to determine the thermal characteristics of the ***,rheological measurements were used to assess the deformation and rheological behavior of the *** results showed that after 1 day,good swelling without loss of mechanical strength was achieved with the composite synthesized using 10%AM,15%AMPS,6%PGV,and 10%ATP.

关键词： Polymer Clay Water shut-off Conformance Swelling

Mathematical modeling and simulations of stress mitigation by coating polycrystalline particles in lithium-ion batteries

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 947-962页

作者： n.IQBAL J.CHOI S.f.SHAH C.LEE S.LEE department of Mechanical Roboticsand Energy EngineeringDongguk University-SeoulSeoul 04620Republic of Korea

A chemo-mechanical model is developed to investigate the effects on the stress development of the coating of polycrystalline ni-rich LinixMnyCo_(z)O_(2)(x≥0.8)(nMC)particles with poly(3,4-ethylenedioxythiophene)(PEdOT).The simulation results show that the coating of primary nMC particles significantly reduces the stress generation by efficiently accommodating the volume change associated with the lithium diffusion,and the coating layer plays roles both as a cushion against the volume change and a channel for the lithium transport,promoting the lithium distribution across the secondary particles more ***,the lower stiffness,higher ionic conductivity,and larger thickness of the coating layer improve the stress *** paper provides a mathematical framework for calculating the chemo-mechanical responses of anisotropic electrode materials and fundamental insights into how the coating of nMC active particles mitigates stress levels.

关键词： lithium-ion battery(LIB) polycrystalline particle coating finite element simulation ni-rich LinixMnyCo_(z)O_(2)(x>0.8)(nMC)