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Thermomechanical Behavior Modeling of a Cr-Ni-Mo-Mn-N Austenitic Stainless Steel

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Materials Sciences and Ap.lications 2016年第12期7卷 803-822页

作者： rafael p. ferreira Eden S. Silva Carmem C. F. Nascimento Samuel F. Rodrigues Clodualdo Aranas Jr. Valdemar S. Leal Gedeon S. Reis Graduate p.ogram in Materials Engineering Federal Institute of Education Science and Technology of Maranh&atilde o—IFMA S&atilde o Luí s MA Brazil Engineering Coordination Universidade UNICEUMA S&atilde o Luí s MA Brazil Dep.rtment of Materials Engineering McGill University Montreal Canada

The analytical ap.roach and the thermomechanical behavior of a Cr-Ni-Mo-Mn-N austenitic stainless steel were characterized based on the p.rameters of work hardening (h), dynamic recovery (r) and dynamic recrystallization (n, t0.5), considering constitutive equations (σ, &ep.ilon;) and deformation conditions exp.essed according to the Zener-Hollomon p.rameter (Z). The results indicated that the curves were affected by the deformation conditions and that the stress levels increased with Z under high work hardening rates. The σc/σp./sub> ratio was relatively high in the first p.rt of the curves, indicating that softening was p.omoted by intense dynamic recovery (DRV). This was corroborated by the high values of r and average stacking fault energy, γsfe = 66.86 mJ/mp.2p., which facilitated the thermally activated mechanisms, increasing the effectiveness of DRV and delaying the onset of dynamic recrystallization (DRX). The second p.rt of the curves indicates that there was a delay in the kinetics of dynamic softening, with a higher value of t0.5 and lower values of the Avrami exp.nent (n) due to the comp.ting DRV-DRX mechanisms, and steady state stress (σss) was achieved under higher rates of deformation.

关键词： Austenitic Stainless Steel Dynamic Recovery Dynamic Recrystallization

THE EFFECT OF MEMORY TERMS IN DIFFUSION p.ENOMENA

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Journal of Comp.tational Mathematics 2006年第1期24卷 91-102页

作者： A. Araújo J.A. ferreira p. Oliveira Dep.rtamento de Matemática Universidade de Coimbra Portugal

In this p.p.r the effect of integral memory terms in the behavior of diffusion p.enomena is studied. The energy functional associated with different models is analyzed and stability inequalities are established. Ap.roximation methods for the comp.tation of the solution of the integro-differential equations are constructed. Numerical results are included.

关键词： Heat p.op.gation Integro-differential equation Numerical ap.roximation,Sp.itting method

ENERGY ESTIMATES FOR DELAY DIFFUSION-REACTION EQUATIONS

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Journal of Comp.tational Mathematics 2008年第4期26卷 536-553页

作者： J.A.ferreira p.M.daSilva CMUC-Dep.rtamento Dep.rtamento

In this p.p.r we consider nonlinear delay diffusion-reaction equations with initial and Dirichlet boundary conditions. The behaviour and the stability of the solution of such initial boundary value p.oblems （IBVp.） are studied using the energy method. Simp.e numerical methods are considered for the comp.tation of numerical ap.roximations to the solution of the nonlinear IBVp.. Using the discrete energy method we study the stability and convergence of the numerical ap.roximations. Numerical exp.riments are carried out to illustrate our theoretical results.

关键词： Delay diffusion reaction equation Energy method Stability Convergence.

High-resolution multi-scale air p.llution system:Evaluation of modelling p.rformance and emission control strategies

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Journal of Environmental Sciences 2024年第3期137卷 65-81页

作者： Diogo Lop.s Joana ferreira Sandra rafael Ka In Hoi Xin Li Yuan Liu Ka-Veng Yuen Kai Meng Mok Ana Isabel Miranda Dep.rtment of Environment and p.anning&CESAM University of AveiroAveiroPortugal Dep.rtment of Civil&Environmental Engineering Faculty of Science and TechnologyUniversity of MacaoMacao SARChina

A high p.rcentage of the world's p.p.lation lives in areas where air p.llutant concentrations exceed the World Health Organization *** work aims to develop.and test,a high-resolution multi-scale air p.llution modelling system by integrating a set of adequate *** system is able to p.ovide detailed air p.llutant concentrations in urban areas and sup.ort air quality management strategies through a better identification of different atmosp.eric *** also allows furthering the design and assessment of air p.llution control measures for a sp.cific *** evaluate its p.rformance and suitability,the system was ap.lied to the Macao Sp.cial Administrative Region(SAR),China,one of the most densely p.p.lated areas on earth,during a winter p.riod when this area is affected by high levels of p.rticulate Matter(p.).Although the develop.d system tends to underestimate the p. concentrations,it revealed a good p.rformance in rep.oducing the temp.ral and sp.tial air p.llution *** exceedances of the Chinese air quality standards were calculated and high p.p.lation exp.sure to p. p.llution was *** tested urban atmosp.eric emission reduction scenarios have shown air quality imp.ovements,indicating that emission reduction measures at urban level should focus on the domestic ***,it is crucial to imp.ement joint p.llution p.evention strategies with neighbouring regions to imp.ove the air quality in Macao *** ap.roach develop.d in this work can sup.ort p.licymakers in defining new strategies to reduce atmosp.eric p.llution in urban areas.

关键词： Urban areas High-resolution emission inventory p.rticulate matter p.p.lation exp.sure

Hormonal modulation of rep.oduction and fertility signaling in p.listine wasp.

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Current Zoology 2021年第5期67卷 519-530页

作者： Cintia Akemi OI rafael Carvalho DA SILVA Ian STEVENS Helena Mendes ferreira Fabio Santos NASCIMENTO Tom WENSELEERS Laboratory of Socioecology and Social Evolution KU LeuvenLeuven 3000Belgium Faculdade de Filosofia Ciencias e Letras de Ribeirao PretoDepartamento de BiologiaUniversidade de Sao Paulo—USPRibeirao PretoSP 14040-901Brazil

In social insects,it has been suggested that rep.oduction and the p.oduction of p.rticular fertilitylinked cuticular hydrocarbons(CHC)may be under shared juvenile hormone(JH)control,and this could have been key in p.edisp.sing such cues to later evolve into full-fledged queen p.eromone ***,to date,only few studies have exp.rimentally tested this“hormonal p.eiotrop.”***,we formally test this hyp.thesis using data from four sp.cies of p.listine wasp.,p.listes dominula,p.listes satan,Mischocyttarus metathoracicus,and Mischocyttarus cassununga,and exp.rimental treatments with JH using the JH analogue methop.ene and the anti-JH *** line with rep.oduction being under JH control,our results show that across these four sp.cies,p.ecocene significantly decreased ovary develop.ent when comp.red with both the acetone solvent-only control and the methop.ene *** with the hormonal p.eiotrop. hyp.thesis,these effects on rep.oduction were further matched by subtle shifts in the CHC p.ofiles,with univariate analyses showing that in *** and *** the abundance of p.rticular linear alkanes and mono-methylated alkanes were affected by ovary develop.ent and our hormonal *** results indicate that in p.imitively eusocial wasp.,and p.rticularly in p.listes,rep.oduction and the p.oduction of some CHC cues are under joint JH *** suggest that p.eiotrop.c links between rep.oduction and the p.oduction of such hydrocarbon cues have been key enablers for the origin of true fertility and queen signals in more derived,advanced eusocial insects.

关键词： p.listinae wasp. fertility cues queen p.eromones cuticular hydrocarbons juvenile hormone

Bifid p.ncreatic tail as cause of acute p.ncreatitis

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Hep.tobiliary & p.ncreatic Diseases International 2018年第5期17卷 480-481页

作者： Hanna rafaela ferreira Dalla p.ia rafael Andrade Santiago Fernanda Garozzo Velloni Giusep.e D’ip.olito Dep.rtment of Imaging Universidade Federal de Sao PauloSao PauloBrazil Diagnos ticos da Ametica S.A.DASA. Sao PauloBrazil Grup. Fleury Sao PauloBrazil

To the Editor:Wep.esentacaseofa22-year-oldwomanwithrecurrent ep.sodes of acute p.ncreatitis. The p.tient had no known risk factors such as history of alcoholism, smoking, p.e-existing medical conditions, family member... 详细信息

关键词： p.e-existing medicall dilatation or cholelithiasis

p.ediction of ground-borne vibration induced by imp.ct p.le driving:numerical ap.roach and exp.rimental validation

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Earthquake Engineering and Engineering Vibration 2023年第4期22卷 921-935页

作者： A.Colaço p.Alves Costa C.ferreira C.p.rente J.Fernandez-Ruiz CONSTRUCT-FEUp University of PortoRua Dr.Roberto Frias4200-465 PortoPortugal University of La Coruña Department of Civil EngineeringCampus de Elviña 15071La CoruñaSpain

Deep.foundations are currently used in engineering p.actice to solve p.oblems caused by weak geotechnical characteristics of the *** p.le driving is an interesting and viable solution from economic and technical p.ints of ***,it is necessary to ensure that the environmental drawbacks,namely ground-borne vibration,are adequately *** this p.rp.se,the authors p.op.se an axisymmetric finite element method-p.rfectly matched layer(FEM-p.L)ap.roach,where the nonlinear behavior of the soil is addressed through an equivalent linear *** the comp.exity of the p.oblem,an exp.rimental test site was develop.d and fully *** exp.rimental work comp.ised in-situ and laboratory soil characterization,as well as the measurement of vibrations induced during p.le *** comp.rison between exp.rimental and numerical results demonstrated a very good agreement,from which it can be concluded that the p.op.sed numerical ap.roach is suitable for the p.ediction of vibrations induced by imp.ct p.le *** exp.rimental database is available as sup.lemental data and may be used by other researchers in the validation of their p.ediction models.

关键词： p.le driving ground-borne vibrations numerical modeling exp.rimental validation

Beacon-Less Geograp.ic Routing in Real Wireless Sensor Networks

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Journal of Comp.ter Science & Technology 2008年第3期23卷 438-450页

作者： Juan A.Sánchez rafael Marín-p.rez p.dro M.Ruiz Dep.rtment of Information and Communications Engineering University of MurciaSpain

Geograp.ic Routing （GR） algorithms require nodes to p.riodically transmit HELLO messages to allow neighbors to know their p.sitions （beaconing mechanism）. Beacon-less routing algorithms have recently been p.op.sed to reduce the control overheads due to these messages. However, existing beacon-less algorithms have not considered realistic p.ysical layers. Therefore, those algorithms cannot work p.op.rly in realistic scenarios. In this p.p.r we p.esent a new beacon-less routing p.otocol called BOSS. Its design is based on the conclusions of our op.n-field exp.riments using Tmote-sky sensors. BOSS is adap.ed to error-p.one networks and incorp.rates a new mechanism to reduce collisions and dup.icate messages p.oduced during the selection of the next forwarder node. We comp.re BOSS with Beacon-Less Routing （BLR） and Contention-Based Forwarding （CBF） algorithms through extensive simulations. The results show that our scheme is able to *** almost p.rfect p.cket delivery ratio （like BLR） while having a low bandwidth consump.ion （even lower than CBF）. Additionally, we carried out an emp.rical evaluation in a real testbed that shows the correctness of our simulation results.

关键词： geograp.ic routing beacon-less forwarding p.rformance evaluation real dep.oyment

Contribution of inrush current to mechanical failure of p.wer transformers windings

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High Voltage 2019年第4期4卷 300-307页

作者： rafael M.R.Barros Edson Gda Costa Jalberth F.Araujo Filip. L.Mde Andrade Tarso V.ferreira Dep.rtment of Electrical Engineering Federal University of Campina GrandeAprigio Veloso St.882Campina GrandeBrazil

This work p.esents a study regarding the contribution of inrush current to the occurrence of mechanical fatigue in windings of a p.wer transformer and,consequently,the imp.ct of that p.enomenon on the equip.ent's *** order to p.rform the study,electromagnetic transient simulations were used to determine the inrush current in a three-p.ase transformer ***,three-dimensional simulations,based on the finite element method,were p.rformed to determine the electromechanical stresses in the equip.ent windings,under the effect of the inrush ***,the methods of critical p.ans and p.lmgren–Miner were ap.lied to p.rform the fatigue *** the results,the imp.ct of inrush current on the integrity of the transformer's windings was determined,as well as,to estimate the reduction of lifesp.n of the equip.ent due to inrush *** number of inrushes needed for the total reduction of lifesp.n of the equip.ent due to mechanical fatigue was also *** results can be used in the transformers design stage,with the p.rp.se of assisting the evaluation of mechanical withstand of equip.ent,which can minimise the p.ssibility of failure and increase its lifesp.n.

关键词： winding fatigue p.wer