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Simula.ion of the deformable lateral bounda.ies in bia.ial test using DEM

Particuology 2024年第5期88卷 161-175页

作者： a.i momeni Barry Clarke Yong Sheng a.i Hassanpour WSP 3 Wellington PlaceLeedsLS1 4APUK Hull University HullHU6 7RXUK School of Civil Engineering University of LeedsLeedsLS2 9JTUK School of Computer Science University of HullHullHU6 7RXUK School of Chemical and Process Engineering University of LeedsLeedsLS2 9JTUK

Applying the discrete element method(DEM)in soil mecha.ics can provide abundant informa.ion at the particle-scale and fa.ilitates illustra.ion of the macro-mecha.ical beha.iour of soils based on the inter-particle *** tria.ial test is one of the most common laboratory methods to study the macro-mecha.ical beha.iour of particulate materials such as ***,many problems in geotechnical design can be assumed and simplified as a plane strain *** a bia.ial test can be conducted to reproduce the macro-mecha.ical beha.iour of soil,where the sample is enclosed by two horizontal rigid platens and a vertical latex membrane,which is a deformable continuous element and allows the enclosed specimen to deform freely while maintaining confining stress during *** paper presents an algorithm to represent physical and mecha.ical characteristics of latex membrane in the 2D DEM simula.ion of bia.ial test using the PFC^(2D) *** investigate the impact of the lateral boundary conditions on the micro-macro mecha.ical beha.iours of soil samples,two sets of DEM bia.ial tests are conducted,*** rigid and deformable lateral boundary *** DEM modeling results indicate that the lateral boundary conditions have a significant effect on the micro-scale fabric properties,thickness and inclina.ion of the shear *** compa.ison between these two simula.ions also demonstrates that the lateral boundary conditions play a major role in the peak and post-peak stress-strain beha.iours as well as the dila.ion and critical state beha.iours of granular soils.

关键词： Discrete element method Bia.ial test Deformable bounda.ies Shear band Critical state Fabric a.isotropy Geometrical sta.ility index

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Evalua.ion the Properties of Polycaprolactone/Fluorapa.ite Nano-biocomposite

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Journal of Bionic Engineering 2022年第1期19卷 179-187页

作者： Mojtaba momeni Kamran a.ini a.i Heida.i Mohammad Khoda.i Department of Mecha.ical Engineering Khomeinishahr BranchIslamic Azad UniversityKhomeinishahr84181-48499IsfahanIran Center for Advanced Engineering Research Majlesi BranchIslamic Azad University86316-56451IsfahanIran Materials Engineering Group Golpayegan College of EngineeringIsfahan University of Technology87717-67498GolpayeganIran

in this study,nano-biocomposites of polycaprolactone(PCL)as the matrix and different amounts of nanofluorapa.ite(nFA)(0,10,20 and 30 wt.%)as the reinforcement were prepared for possible scaffold fabrica.ion using the fused filament fabrica.ion(FFF)3D *** Emission Scanning Electron Microscopy(FE-SEM)and Energy Dispersive Spectroscopy(EDS)showed that nFA particles were well distributed in the PCL matrix.X-ray diffraction analysis(XRD)and Fourier Transform infrared Spectroscopy(FTiR)depicted no chemical interaction between the elements of the *** Scanning Calorimetric(DSC)analysis was then used to assess the thermal properties of the composites,suggesting that this could be due to the amorphous phase forma.ion of the intermolecular hydrogen bonds between PCL and nFA,resulting in the suppression of PCL *** results of mecha.ical characteriza.ion also showed that the addition of nFA up to 20 wt.%to the PCL increased the tensile and yield strength,as well as reducing the elonga.ion at both yield and failure points and increa.ing the Young *** best mecha.ical properties were obtained for the PCL/20nFA *** strength and Young modulus were increased by 30%and 179%,respectively;meanwhile,elonga.ion of PCL/20nFA was decreased by 70%,as compared to the naked *** changes could be attributed to the better distribution of the nFA filler in the PCL *** to the obtained results,PCL/20nFA could be regarded as a good composite in terms of the mecha.ical properties for the regenera.ion of the bone tissue.

关键词： Nano-biocomposite Polycaprolactone Fluorapa.ite Bone tissue engineering Mecha.ical properties

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Novel Hybrid X GBoost Model to Forecast Soil Shear Strength Based on Some Soil index Tests

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Computer Modeling in Engineering & Sciences 2023年第9期136卷 2527-2550页

作者： Ehsan momeni Biao He Ya.in Abdi Da.ial Jahed Armagha.i Department of Civil Engineering Faculty of EngineeringLorestan UniversityKhorramabad***Iran Department of Civil Engineering Faculty of EngineeringUniversiti MalayaKuala Lumpur50603Malaysia Department of Geology Faculty of SciencesLorestan UniversityKhorramabad***Iran Department of Urban Planning Engineering Networks and SystemsInstitute of Architecture and ConstructionSouth Ural State UniversityChelyabinsk454080Russia

When building geotechnical constructions like retaining walls and dams is of interest,one of the most important factors to consider is the soil’s shear strength *** study makes an effort to propose a novel predictive model of shear *** study implements an extreme gra.ient boosting(XGBoost)technique coupled with a powerful optimiza.ion algorithm,the salp swarm algorithm(SSA),to predict the shear strength of va.ious *** do this,a database consisting of 152 sets of data.is prepared where the shear strength(τ)of the soil is considered as the model output and some soil index tests(e.g.,dry unit weight,water content,and plasticity index)are set as model *** is designed and tuned using both effective parameters of XGBoost and SSA,and themost accuratemodel is introduced in this *** theSSA-XGBoostmodel is assessedbased on the coefficient of determina.ion(R2)and va.iance account for(VAF).Overall,the obtained values of R^(2) and VAF(0.977 and 0.849)and(97.714%and 84.936%)for training and testing sets,respectively,confirm the worka.ility of the developed model in forecasting the soil shear *** investigate the model genera.iza.ion,the prediction performance of the model is tested for another 30 sets of data(va.ida.ion data).The va.ida.ion results(e.g.,R^(2) of 0.805)suggest the worka.ility of the proposed ***,findings suggest that when the shear strength of the soil cannot be determined directly,the proposed hybrid XGBoost-SSA model can be utilized to assess this parameter.

关键词： Predictive model salp swarm algorithm soil index tests soil shear strength XGBoost

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Tribological beha.ior of ZK60Gd alloy reinforced by SiC particles after precipita.ion hardening

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Journal of Magnesium and Alloys 2023年第9期11卷 3362-3381页

作者： Ehsan momeni Hassan Sha.ifi Morteza Tayebi Ahmad Keyva.i Ermia Aghaie Yashar Behna.ian Department of Materials Science and Engineering University of ShahrekordIran Young Researchers and Elites Club Science and Research BranchIslamic Azad UniversityTehranIran Department of Chemical and Materials Engineering University of AlbertaEdmontonAlberta T6G 1H9Canada

in this research, the effect of precipita.ion hardening on the tribological beha.ior of the ZK60Gd/SiC composite was studied. For this purpose, ZK60Gd alloy containing with 5 and 10 wt% SiC were produced with stir casting method. The microstructure characteriza.ion of the samples showed the wide distributions of Mg_(7)Zn_(3) and Gd(Mg_(0.5)Zn_(0.5)) precipitates were formed during casting. The results of hardness measurement after precipita.ion hardening at different temperatures showed that the hardness peck was obtained at 175 ℃. The wear tests with different loads(10, 40, 60, 90, and 120 N) and velocities(0.1, 0.3, 0.6, and 0.9 m/s) were performed on the as-cast and heat treated sample at 125, 175, and 225 for 12 h. Between the different precipita.ion hardening conditions, the precipita.ion hardened samples at 175 ℃ had the highest hardness values and least wear rate. The sample containing 10% reinforcement had the least wear rate between the unreinforced alloy and the composites. The results showed that abra.ive, adhesive, dela.ina.ion, MML, and fa.igue wear mecha.isms were the dominant wear mecha.isms for the composite samples. in contrast, the dominant wear mecha.ism for the unreinforced samples was abra.ive, adhesive,dela.ina.ion, MML, and plastic deforma.ion.

关键词： Precipita.ion hardening Composite Gadolinium Mg-Zn-Zr-Gd Wear map

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Genera.ing one-,two-,three-and four-scroll attractors from a novel four-dimensional smooth autonomous chaotic system

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Chinese Physics B 2010年第6期19卷 106-114页

作者： Sara Dadras Ha.id Reza momeni Automa.ion and instruments Lab Electrical Engineering DepartmentTarbiat Modares UniversityP.O.Box 14115-143TehranIran

A new four-dimensional quadra.ic smooth autonomous chaotic system is presented in this paper, which can exhibit periodic orbit and chaos under the conditions on the system parameters. importantly, the system can generate one-, two-, three- and four-scroll chaotic attractors with appropriate choices of parameters. interestingly, all the attractors are generated only by changing a single parameter. The dyna.ic analysis approach in the paper involves time series, phase portraits, Poincare maps, a bifurca.ion diagram, and Lyapunov exponents, to investigate some ba.ic dyna.ical beha.iours of the proposed four-dimensional system.

关键词： new smooth autonomous four-dimensional chaotic system multi-scroll chaotic attractor Poincare mapping bifurca.ion Lyapunov exponent

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Syringic a.id induces cancer cell death in the presence of Cu(Ⅱ)ions via pro-oxidant activity

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a.ian Pa.ific Journal of Tropical Biomedicine 2022年第6期12卷 270-278页

作者： Marzieh Rashedinia a.ita Nasrolla.i Marzieh Shafaghat Shahrzad momeni Forough iranpak Ja.ileh Saberzadeh Rita Arabsolghar Zahra Saba.i Medicinal Plants Processing Research Center Shiraz University of Medical SciencesShirazIran Department of Pharmacology and Toxicology Faculty of PharmacyShiraz University of Medical SciencesShirazIran Diagnostic Laboratory Sciences and Technology Research Center School of Paramedical SciencesShiraz University of Medical SciencesShirazIran Department of Biochemistry Islamic Azad University of ShirazShirazIran Department of Medical Laboratory Sciences School of Paramedical SciencesShiraz University of Medical SciencesShirazIran

Objective:To investigate the effects of syringic a.id on HEK 293 and HepG2 cells in the absence and presence of exogenous Cu(Ⅱ)and Fe(Ⅱ)***:The antiprolifera.ive effects of syringic a.id on HEK 293 and HepG2 cells in the absence and presence of exogenous Cu(Ⅱ)and Fe(Ⅱ)ions were exa.ined by MTT ***,colony-forming,reactive oxida.ive species(ROS)genera.ion,apoptosis induction,autophagy,mitochondrial membrane potential,and mitochondrial mass were ***:At 24 and 72 h,no significant differences were observed in the via.ility of HepG2 cells between the control and syringic a.id+Fe(Ⅱ)***,exposure of HepG2 cells to syringic a.id+Cu(Ⅱ)for 72 h reduced the cell via.ility ***,ROS forma.ion,induction of apoptosis,and autopha.ic vacuoles were significantly increased in HepG2 cells without marked changes in mitochondrial membrane potential and mitochondrial ***,syringic a.id+Cu(Ⅱ)reduced the pla.ing efficiency and surviving fraction ***:The combina.ion of syringic a.id with Cu(Ⅱ)was toxic to cancer cells and showed pro-oxidant *** addition,this combina.ion induced autophagy in cancer cells with less cytotoxic effects on normal cells,which is a potential candidate for the development of novel therapeutics towards cancer.

关键词： Syringic a.id Copper iron Cancer cell Pro-oxidant Autophagy

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Dye-sensitized solar cells based on Cr-doped TiO2 nanotube photoanodes

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Rare Metals 2017年第11期36卷 865-871页

作者： M. M. momeni Department of Chemistry Isfahan University of TechnologyIsfahan 84156-83111 Iran

The effect of chromium doping on the photo- voltaic efficiency of dye-sensitized solar cells （DSSCs） with anodized TiO2 nanotubes followed by an annea.ing process was investigated. Cr-doped TiO2 nanotubes （CrTNs） with different amounts of chromium were obtained by anodizing of tita.ium foils in a single-step process using potassium chro- mate as the chromium source. Film features were investigated by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, energy-dispersive X-ray spectroscopy （EDX）, and ultra.iolet-visible （UV-Vis） spectroscopy. it is clearly seen that highly ordered TiO2 nanotubes are formed in an anodizing solution free of potassium chromate, and with a gradual increase in the potassium chromate concentra.ion, these nanotube structures change to nanoporous and compact films without porosity. The photovoltaic efficiencies of fabricated DSSCs were characterized by a solar cell measurement sys- tem via the photocurrent-voltage （l-V） curves. it is found that the photovoltaic efficiency of DSSCs with CrTNsl sample is improved by more than three times compared to that of DSSCs with undoped TNs. The energy conversion efficiency increases from 1.05 % to 3.89 % by doping of chromium.

关键词： Dye-sensitized solar cell Photoanodes Nanotubes Anodiza.ion

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Effect of Hot Working on Secondary Phase Forma.ion in 2205 Duplex Stainless Steel

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Journal of Materials Science & Technology 2010年第9期26卷 851-857页

作者： A.momeni K.Dehgha.i Department of Mining and Metallurgy Amir Kabir University of Technology

in this research,a.ing treatments at temperatures of 800 and 900°C for different a.ing time of 5-60 min were conducted on solution treated as well as hot worked samples of 2205 dual phase stainless *** effect of a.ing treatment on precipita.ion of intermetallic phases was investigated in undeformed specimens and those subjected to hot deforma.ion with different strain rates of 0.001-1 *** was found that σ precipita.ion increased by hot *** was also concluded that the volume fraction of phase increased with deforma.ion temperature and decreased with strain *** precipita.ion of intermetallic phases（i.e.σ and χ） was analyzed by an Avra.i-type kinetics equa.ion of %（σ＋χ）=A（1-exp（-ktn）） and the values of n and ln k were estimated for different thermomecha.ical *** values of n were assessed to increase from 0.4 to 1 with strain rate in the studied ***,it was also understood that ln k decreased with strain *** observa.ions by means of optical microscopy and scanning electron microscopy showed that σ particles mostly nucleated at the ferrite-austenite *** no sign of χ-phase could be *** fortified the idea of certain literature that χ-phase always forms at early stages of a.ing and consumes through the precipita.ion of σ.

关键词： Duplex stainless steel a.ing Hot working σ phase

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Repetitive Thermomecha.ical Processing towards Ultra Fine Grain Structure in 301,304 and 304L Stainless Steels

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Journal of Materials Science & Technology 2011年第4期27卷 338-343页

作者： A.momeni S.M.Abba.i Department of Mining and Metallurgical Engineering Amirkabir University of Technology KNT University of Technology

Thermomecha.ical processing as a combina.ion of cold rolling and annea.ing was performed on austenitic stainless steels 301,304 and 304L. Two cold rolling steps each one up to a reduction of 75% were combined with an intermediate annea.ing at 800℃ for 20 min. The final annea.ing was performed *** same temperature and time. Cold rolling contributed to martensite forma.ion at the expense of metastable austenite in the studied materials. Austenite in 301 was found to be less stable than that in 304 and 304L. Hence, higher strength characteristics in the as-quenched 301 stainless steels were attributed to the higher volume fraction of martensite. Both α′-martensite and ε-martensite were found to form as induced by deforma.ion. However, the intensity of ε-martensite increased as the sta.ility of austenite decreased. Annea.ing after cold rolling led to the reversion of austenite with an ultra fine grained structure in the order of 0.5-1 μm from the strain induced martensite. The final grain size was found to be an inverse function of the amount of strain induced martensite. The thermomecha.ical processing considerably improved the strength characteristics while the simultaneous decrease of elonga.ion was rather low.

关键词： Austenitic stainless steel Cold rolling Ultra fine grain Deforma.ion induced martensite

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Universa.ity of a Critical Magnetic Field in a Holographic Superconductor

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Chinese Physics Letters 2015年第4期32卷 113-117页

作者： D.momeni R.Myrzakulov Eura.ian interna.ional Center for Theoretical Physics and Department of General and Theoretical Physics Eurasian National University

We study aspects of holographic superconductors analytically in the presence of a constant external magnetic field. it is shown that the critical temperature and the critical magnetic field can be calculated at nonzero temperature. We detect the Meissner effect in such superconductors. A universal rela.ion between black hole mass and critical magnetic field Hc is proposed to be Hc/M2/3≤0.687365. We also discuss some aspects of phase transition in terms of black hole entropy and Bekenstein＇s entropy to the energy upper bound.

关键词： Entropy

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