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the relation between ductility at high temperature and solid solution in mg alloys

Journal of magnesium and Alloys 2022年第1期10卷 241-256页

作者： D.F.Shi C.m.Cepeda-Jiménez m.t.pérez-prado Im DEA materials Institute C/Eric Ka ridel228906 GetafeMadridSpain Department of materials Science Polytechnic University of Madrid/Universidad Politecnica de MadridE.T.S.de Ingenieros de Caminos28040MadridSpain Department of physical metallurgy CENIMCSICAv.Gregorio del Amo 828040 MadridSpain

this work investigates the effect of solid solution on ductility and on the activation of individual deformation mechanisms at moderate temperatures and at quasi-static strain rates in mg-Zn and mg-Al alloys. With that aim, four solid solution mg-Zn and mg-Al binary alloy ingots containing 1 and 2 wt.% solute atoms were subjected to hot rolling and subsequent annealing to generate polycrystals with similar average grain size and basal-type texture for each composition. the activity of the different slip systems after tensile testing at 150°C and at 250°C was evaluated in pure mg and in the alloys by EBSD-assisted slip trace analysis. In addition, segregation of Zn and Al atoms at grain boundaries during the thermo-mechanical processing was characterized by HAADF-StEm and EDX. It was found that while the addition of Al and Zn atoms to pure mg does not lead to major changes in the mechanical strength at the investigated temperatures, it does enhance ductility significantly, especially at 250℃. Our results show that this increase in ductility cannot be attributed to a higher activation of non-basal systems in the alloys, as reported earlier, as the incidence of non-basal systems is indeed considerably higher in pure mg. this work suggests, on the contrary, that the ductility increase may be attributed to the presence of a more homogenous basal activity in the alloys due to a lower degree of orientation clustering, to grain boundary solute segregation, and to a higher slip diffusivity at grain interiors.

关键词： magnesium Solute segregation Slip trace analysis Ductility Deformation mechanisms

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A quantitative microplasticity-based approach to rationalize the poor strengthening response of polycrystalline mg alloys

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Journal of magnesium and Alloys 2023年第5期11卷 1656-1671页

作者： X.Z.Jin W.C.Xu D.B.Shan B.Guo B.Jin m.t.pérez-prado National Key Laboratory for precision Hot processing of metals&School of materials Science and Engineering Harbin Institute of TechnologyHarbin 150001PR China ImDEA materials Institute C/Eric Kandel2GetafeMadrid 28906Spain Advanced Composites Simulation Lab University of Southern CaliforniaLos AngelesCA 90089U.S.A m.C.Gill Composites Center University of Southern CaliforniaLos AngelesCA 90089U.S.A

this work aims to understand the inefficiency of nanoprecipitates to strengthen a weakly textured,polycrystalline mg-Gd-Y-Zr *** experimental micromechanical approach consisting on micropillar compression combined with analytical electron microscopy is put in place to analyze the effect of nanoprecipitation on soft and hard basal slip and twinning in individual grains with different *** study shows that,in grains that are favorably oriented for basal slip(“soft”basal slip),aging leads to extreme localization due to the ability of basal dislocations to shear the nanoparticles,resulting overall in the softening of basal ***,in grains in which the c-axis is almost perpendicular to the compression axis,prismatic slip dominates deformation in the solid solution state and nanoprecipitation favors twinning due to the concomitant lattice solute ***,in grains oriented with their c-axis making an angle of about 5-7°with respect to the compression axis,which deform mainly by“hard”basal slip,precipitation leads to the strengthening of basal systems in the absence of obvious *** work reveals that the poor hardening response of the polycrystalline alloy is related to the capability of basal dislocations to shear the nanoparticles,in the absence of Orowan looping events,and to the associated basal slip localization.

关键词： magnesium precipitation Basal slip particle shearing Slip localization

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transport mechanism in chemically reactive hybrid nanofluid flow containing gyrotactic micro-organisms over a curved oscillatory surface

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Applied mathematics and mechanics(English Edition) 2025年第1期46卷 177-192页

作者： m.NAVEED m.ImRAN t.ASGHAR Z.ABBAS Department of mathematics Division of Science and TechnologyUniversity of Education Department of mathematics The Islamia University of Bahawalpur

this paper examines the transport analysis, including both heat transfer and mass transfer, in hybrid nanofluid flow containing gyrotactic microorganisms towards a curved oscillatory surface. the influence of magnetic fields is also inspected in terms of their physical characteristics. to depict the phenomena of transport, modified versions of both Fick's and Fourier's laws are used. Additionally, the characteristics of both heterogeneous and homogeneous chemical reactions are also incorporated. Utilizing a curvilinear coordinate system, the flow problem is formulated as partial differential equations(pDEs)for momentum, concentration, microorganism field, and energy. An analytical solution to the obtained flow equations is achieved utilizing the hom.t.py analysis method(HAm).the effects of significant flow parameters on the pressure and microorganism fields, velocity, oscillation velocity, concentration, and temperature distributions are shown via graphs. Furthermore, the variations in skin friction, mass transfer rate, heat transfer rate, and local motile number due to different involved parameters are presented in tables and are analyzed in detail. Graphical results indicate that the curves of velocity and temperature fields are enhanced as the values of the solid volume fraction variables *** is also verified that the concentration rate field decreases as the values of the homogeneous reaction strength parameter and the radius of curvature parameter increase, and it increases with the Schmidt number and the heterogeneous reaction strength *** outcomes show a favorable response of the motile number to advanced values of the peclet number, the Schmidt number, the microorganism difference parameter, and the bio-convective Lewis number.

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Intestinal pseudo-obstruction caused by herpes zoster:Case report and pathophysiology

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World Journal of Clinical Cases 2018年第6期6卷 132-138页

作者： Roberto Anaya-prado José V pérez-Navarro Ana Corona-Nakamura michelle m Anaya-Fernández Roberto Anaya-Fernández marian Eliza Izaguirre-pérez Department of Surgery at Western medical Center the Mexican Institute of Social Security Division of Research at Autonomous University of Guadalajara Department of Infectious Diseases at Western medical Center the Mexican Institute of Social Security Division of Research at University of Guadalajara

Herpes zoster(HZ) infection occurs in approximately 10% to 30% of individuals. Visceral neuropathies secondary to HZ can cause cystitis and urinary retention. But colonic pseudo-obstruction can also occur. peripheral neuropathy may reveal segmental motor paresis of either upper or lower limbs, the abdominal muscles or the diaphragm. We report the case of a 62-year-old male patient who presented with abdominal distention and cutaneous vesicular eruption on the left side of the abdominal wall. plain X-rays and computed tomography scan showed distended small bowel. A diagnosis of intestinal pseudo-obstruction was made secondary to segmental paresis of the small intestine and visceral neuropathy. Conservative management was successful and the patient was discharged uneventfully. Intestinal pseudo-obstruction ought to be consideredwhen dealing with non-obstructive(adynamic) conditions of the digestive tract associated with HZ infection; since early recognition may help to avoid unnecessary surgery.

关键词： Ogilvie’s symdrome Herpes zoster virus Neuropathies Intestinal pseudo-obstruction

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Global evolution of Equidae and Gomphotheriidae from South America

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Integrative Zoology 2014年第4期9卷 434-443页

作者： JoséL.prado maría t.ALBERDI INCUApA CONICET-UNICENNational University of Central Buenos Aires ProvinceOlavarríaArgentina Department of paleobiology Museo Nacional de Ciencias NaturalesCSICMadridSpain

the contemporary South American mammalian communities were determined by the emergence of the Isthmus of panama and by the profound climatic oscillations during the *** and gomphotheres were 2 very conspicuous groups of immigrant mammals from North America that arrived in South America during the *** present study compiles updated data on the phylogeny,systematics and ecology of both groups in South *** horses in South America are represented by 2 genera,Hippidion and Equus,as are the gomphotheres,represented by Cuvieronius and *** genera of horses include small(Hippidion devillei,***,*** and ***)and large forms(Equus neogeus and ***),which dispersed into South America using 2 different *** possible model for this dispersion indicates that the small forms used the Andes corridor,while larger horses dispersed through the eastern route and through some coastal *** the case of gomphotheres,Cuvieronius and Stegomastodon reached South America in 2 independent dispersal events,and Cuvieronius dispersed across the Andean corridor,while large Stegomastodon spread along the eastern *** and gomphotheres present values ofδ^(13)C from woodlands to C4 grass*** present lower values ofδ^(13)C than Equus in the late pleistocene,whereas the gomphotheres diverge from value ofδ^(18)O,reflecting that Cuvieronius inhabited the Andean corridor and Stegomastodon dispersed through eastern *** gomphothere and horse species recorded in South America became extinct around the time that humans arrived.

关键词： Equidae Gomphotheriidae plio-pleistocene South America

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Synergistic fibroblast optimization: a novel nature-inspired computing algorithm

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Frontiers of Information technology & Electronic Engineering 2018年第7期19卷 815-833页

作者： t t DHIVYApRABHA p SUBASHINI m KRISHNAVENI Department of Computer Science Avinashilingam Institute for Home Science and Higher Education for Women

the evolutionary algorithm, a subset of computational intelligence techniques, is a generic population-based stochastic optimization algorithm which uses a mechanism motivated by biological concepts. Bio-inspired computing can implement successful optimization methods and adaptation approaches, which are inspired by the natural evolution and collective behavior observed in species, respectively. Although all the meta-heuristic algorithms have different inspirational sources, their objective is to find the optimum(minimum or maximum), which is problem-specific. We propose and evaluate a novel synergistic fibroblast optimization(SFO) algorithm, which exhibits the behavior of a fibroblast cellular organism in the dermal wound-healing process. Various characteristics of benchmark suites are applied to validate the robustness, reliability, generalization, and comprehensibility of SFO in diverse and complex situations. the encouraging results suggest that the collaborative and self-adaptive behaviors of fibroblasts have intellectually found the optimum solution with several different features that can improve the effectiveness of optimization strategies for solving non-linear complicated problems.

关键词： Synergistic fibroblast optimization (SFO) Fitness analysis Convergence Benchmark suite monk's dataset

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three bona fide plant-specific SAGA subunits and their regulatory function

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molecular plant 2021年第7期14卷 1033-1035页

作者： J.S.Ramirez-prado m.Benhamed Centre of microbial and plant Genetics KU Leuven3001 LeuvenBelgium lnstitute of plant Sciences paris-Saclay(IpS2) Universite Paris-SaclayCNRSINRAEUniv EvryOrsay 91405France Institute of plant Sciences paris-Saclay Universite de ParisCNRSINRAEOrsay(IPS2)91405France lnstitut Universitaire de France(IUF) ParisFrance

Nucleosomal histone tails are subject to a vast repertoire of covalent modifications that alter the physical accessibility of their associated DNA,impacting gene ***,the acetylation of histones is associated with transcriptional activation,as it has been shown to reduce their affinity for DNA(Grant,2001).the dynamic changes on histone acetylation levels throughout development are the result of active acetylation and deacetylation processes,mediated by histone acetyltransferases(HAts)and deacetylases,respectively.

关键词： expression. SAGA transcriptional

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Doped graphene/carbon black hybrid catalyst giving enhanced oxygen reduction reaction activity with high resistance to corrosion in proton exchange membrane fuel cells

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Journal of Energy Chemistry 2022年第5期31卷 143-153页

作者： Zhaoqi Ji Jianuo Chen maría pérez-page Zunmin Guo Ziyu Zhao Rongsheng Cai maxwell t.p.Rigby Sarah J.Haigh Stuart m.Holmes School of Automotive Engineering Harbin Institute of TechnologyWeihai264209ShandongChina Department of Chemical Engineering and Analytical Science The University of ManchesterManchester M139PLUK Department of materials The University of ManchesterManchester M139PLUK

Nitrogen doping of the carbon is an important method to improve the performance and durability of catalysts for proton exchange membrane fuel cells by platinum–nitrogen and carbon–nitrogen bonds. this study shows that p-phenyl groups and graphitic N acting bridges linking platinum and the graphene/carbon black(the ratio graphene/carbon black = 2/3) hybrid support materials achieved the average size of platinum nanoparticles with(4.88 ± 1.79) nm. It improved the performance of the lower-temperature hydrogen fuel cell up to 0.934 W cm^(-2) at 0.60 V, which is 1.55 times greater than that of commercial pt/C. Doping also enhanced the interaction between pt and the support materials, and the resistance to corrosion, thus improving the durability of the low-temperature hydrogen fuel cell with a much lower decay of 10 mV at 0.80 A cm^(-2) after 30 k cycles of an in-situ accelerated stress test of catalyst degradation than that of 92 mV in pt/C, which achieves the target of Department of Energy(mV). meanwhile,pt/Nr EGO_(2)-CB_(3) remains 78% of initial power density at 1.5 A cm^(-2) after 5 k cycles of in-situ accelerated stress test of carbon corrosion, which is more stable than the power density of commercial pt/C, keeping only 54% after accelerated stress test.

关键词： Nitrogen doped graphene Low-temperature hydrogen fuel cell Catalyst degradation Carbon corrosion

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Feasibility of the 2-point method to determine the load-velocity relationship variables during the countermovement jump exercise

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Journal of Sport and Health Science 2023年第4期12卷 544-552,F0003页

作者： Alejandro pérez-Castilla Rodrigo Ramirez-Campillo John F.t.Fernandes Amador García-Ramos Department of physical Education and Sport Faculty of Sport SciencesUniversity of GranadaGranada 18011Spain Human performance Laboratory Department of Physical Activity SciencesUniversidad de Los LagosSantiago 5170000Chile Centro de Investigacion en Fisiologıa del Ejercicio Facultad de CienciasUniversidad MayorSantiago 8580745Chile Higher Education Sport Hartpury UniversityHartpury GL193BEUK Department of Sports Sciences and physical Conditioning Faculty of EducationUniversidad Catolica de la Santısima ConcepcionConcepcion 4090541Chile

purpose:this study aimed to examine the reliability and validity of load-velocity(L-V)relationship variables obtained through the 2-point method using different load combinations and velocity ***:twenty men performed 2 identical sessions consisting of 2 countermovement jumps against 4 external loads(20 kg,40 kg,60 kg,and80 kg)and a heavy squat against a load linked to a mean velocity(mV)of 0.55 m/s(load_(0.55)).the L-V relationship variables(load-axis intercept(L_(0)),velocity-axis intercept(v_(0)),and area under the L-V relationship line(A_(line)))were obtained using 3 velocity variables(mV,mean propulsive velocity(mpV),and peak velocity)by the multiple-point method including(20-40-60-80-load_(0.55))and excluding(20-40-60-80)the heavy squat,as well as from their respective 2-point methods(20-load_(0.55)and 20-80).Results:the L-V relationship variables were obtained with an acceptable reliability(coefncient of variation(CV)≤7.30%;intra-class correlation coefficient>0.63).the reliability of L_(0)and v_(0)was comparable for both methods(CV_(ratio)(calculated as higher value/lower value):1.11-1.12),but the multiple-point method provided Al_(ine)with a greater reliability(CV_(ratio)=1.26).the use of a heavy squat provided the L-V relationship variables with a comparable or higher reliability than the use of a heavy countermovement jump load(CV_(ratio):1.06-1.19).the peak velocity provided the load-velocity relationship variables with the greatest reliability(CV_(ratio):1.15-1.86)followed by the mV(CV_(ratio):1.07-1.18),and finally the *** 2-point methods only revealed an acceptable validity for the mV and mpV(effect size≤0.19;pearson s product-moment correlation coefficient≥0.96;Lin's concordance correlation coefficient≥0.94).Conclusion:the 2-point method obtained from a heavy squat load and mV or mpV is a quick,safe,and reliable procedure to evaluate the lower-body maximal neuromuscular capacities through the L-V relationship.

关键词： Force-velocity relationship mean velocity multiple-point method peak velocity Velocity-based training

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Resistance of full-scale beams against close-in *** modeling and field tests

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Defence technology（防务技术） 2024年第10期40卷 35-47页

作者： A.prado A.Alañón R.Castedo A.p.Santos L.m.López m.Chiquito m.Bermejo C.Oggeri Escuela politécnica Superior dé Avila Universidad de SalamancaÁvila05003Spain E.t.S.I.minas y Energía Universidad Politecnica de MadridMadrid28003Spain Department of Engineering Aviation and TechnologySaint Louis UniversityMadrid28003Spain Department of Environment Land and Infrastructure Engineering(DIATI)Politecnico di TorinoTorino10129Italy

this paper explores the performances of a finite element simulation including four concrete models applied to a full-scale reinforced concrete beam subjected to blast loading. Field test data has been used to compare model results for each case. the numerical modelling has been, carried out using the suitable code LS-DYNA. this code integrates blast load routine(CONWEp) for the explosive description and four different material models for the concrete including: Karagozian & Case Concrete, Winfrith, Continuous Surface Cap model and Riedel-Hiermaier-thoma models, with concrete meshing based on 10, 15, and 20 mm. Six full-scale beams were tested: four of them used for the initial calibration of the numerical model and two more tests at lower scaled distances. For calibration, field data obtained employing pressure and accelerometers transducers were compared with the results derived from the numerical simulation. Damage surfaces and the shape of rupture in the beams have been used as references for comparison. Influence of the meshing on accelerations has been put in evidence and for some models the shape and size of the damage in the beams produced maximum differences around 15%. In all cases, the variations between material and mesh models are shown and discussed.

关键词： Blast test Numerical simulation LS-DYNA Concrete model mesh effect Full-scale beams

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