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Journal of Central South University 2017年第11期24卷 2556-2564页

作者： Farzadi A morakabiyan esfahani m Alavi Zaree S R Department of mining and metallurgical Engineering Amirkabir University of Technology Department of materials Science and Engineering Faculty of EngineeringShahid Chamran University of Ahvaz

Effects of welding current on temperature and velocity fields during gas metal arc welding(GmAW) of commercially pure aluminum were simulated. Equations of conservation of mass, energy and momentum were solved in a three-dimensional transient model using FLOW-3 D software. The mathematical model considered buoyancy and surface tension driving forces. Further, effects of droplet heat content and impact force on weld pool surface deformation were added to the model. The results of simulation showed that an increase in the welding current could increase peak temperature and the maximum velocity in the weld pool. The weld pool dimensions and width of the heat-affected zone(HAZ) were enlarged by increasing the welding current. In addition, dimensionless Peclet, Grashof and surface tension Reynolds numbers were calculated to understand the importance of heat transfer by convection and the roles of various driving forces in the weld pool. In order to validate the model, welding experiments were conducted under several welding currents. The predicted weld pool dimensions were compared with the corresponding experimental results, and good agreement between simulation and preliminary test results was achieved.

关键词： simulation modeling heat transfer fluid flow AA1100 aluminum alloy finite element method (FEm) weld pool geometry temperature and velocity fields

Accuracy analysis of predicted velocity profiles of laminar duct flow with entropy generation method

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Applied mathematics and mechanics(English Edition) 2013年第8期34卷 971-984页

作者： J.A.esfahani m.mODIRKHAZENI S.mOHAmmADI Center of Excellence on modeling and Control Systems (CEmCS) & Department of mechanical Engineering Faculty of Engineering Ferdowsi University of Mashhad

The objective of this work is to estimate the accuracy of a predicted velocity profile which can be gained from experimental results, in comparison with the exact ones by the methodology of entropy generation. The analysis is concerned with the entropy generation rate in hydrodynamic, steady, laminar, and incompressible flow for Newtonian fluids in the insulated channels of arbitrary cross section. The entropy generation can be calculated from two local and overall techniques. Adaptation of the results of these techniques depends on the used velocity profile. Results express that in experimental works, whatever the values of local and overall entropy generation rates are close to each other, the results are more accuracy. In order to extent the subject, different geometries have been investigated. Also, the influence studied, and the distribution of volumetric geometries is drawn. of geometry on the entropy generation rate is local entropy generation rate for the selected geometries is drawn.

关键词： entropy generation velocity profile duct arbitrary cross section laminarinternal flow

Biological,antibacterial activities and electrochemical behavior of borided commercially pure titanium in BSA-containing PBS

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Transactions of Nonferrous metals Society of China 2020年第4期30卷 944-957页

作者： Adib EBRAHImI Hamid esfahani Omid ImANTALAB Arash FATTAH-ALHOSSEINI Department of materials Engineering Bu-Ali Sina UniversityHamedan 65178-38695Iran

The effects of boride coating on the bioactivity, antibacterial activity, and electrochemical behavior of commercially pure titanium(CP-Ti) in phosphate buffer solution(PBS) with bovine serum albumin(BSA) were studied. The grazing incidence X-ray diffraction(GIXRD) pattern confirmed the formation of a Ti B/Ti B2 coating via boriding process. Scanning electron microscopy(SEm) observation indicated that the Ti B2 cross-linked particles covered the Ti B whiskers. Water contact angle measurements revealed that boriding led to the formation of a surface with intermediate water affinity. Potentiodynamic polarization(PDP) assays demonstrated that the Ti B/Ti B2 coating had acceptable passivation behavior in BSA-containing PBS. Electrochemical impedance spectroscopy(EIS) measurements revealed that the passivation behavior of the CP-Ti and the borided samples was improved by increasing exposure time. Based on the mott-Schottky(m-S) tests, it was realized that the charge carriers of passive films of both samples decreased with increasing exposure time in BSA-containing PBS. The bioactivity test results in a simulated body fluid showed that the Ti B/Ti B2 coating switched the CP-Ti from bioinert to bioactive material. Finally, the antibacterial activity test of the Ti B/Ti B2 coating against Escherichia coli and Staphylococcus aureus indicated 99% antibacterial activity.

关键词： electrochemical behavior boriding BSA-containing PBS passive film titanium boride

Assessment of Variabilities in Wheat Genotypes to Yellow and or Strip Rust, Puccinia striiformis in Glass House Conditions

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Journal of Agricultural Science and Technology(A) 2011年第2X期1卷 255-261页

作者： m. Nasr esfahani m. monazah G. Alizade Sh. Rafizadeh Agricultural and Natural Resources Research Center Isfahan 81785199 Iran

Yellow/stripe rust caused by Puccinia striiformis is a major problem in the middle East specially Iran. Virulence survey of cereal rust fungi have traditionally used differential host genotype and virulent physiologic race 134 E 134 AT was received to evaluate the segregating lines. A set of 35 segregating lines and three additional susceptible cultivars were added, making a total of 38 eultivars-lines. Spreader plants served as a source of inoculums. The plants were evaluated after two months based on infection percentage and the disease scoring scales. The results indicated that, there are significant changes in susceptibility assessments of the segregating lines in contrast to cultivated varieties to the yellow rust P. striiformis as far as the disease incidence and rust development is concerned in these experiments. The selected differential genotypes associated with various levels of resistance. The infection percentages were varied on the lines and the varieties, whereas the severity percentages were entirely different. The lowest severity is of line 38 with 34.70% and the highest in line 1 with 93.49% indicating 2.7 folds reduction in severity. For discrimination among the lines, the results on scoring scales gave distinctions of five classes of resistance, in which, the highest score is 29.93 and the lowest one 11.46. The cluster analysis showed almost similar results and confirmed, the analysis by Duncan＇s multiple-lest rang as the above five distinctive groups.

关键词： Genotype Isfahan race resistance severity varieties.

Reduced Complexity Turbo multi User Detection for a CDmA System Using m-ary PSK

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Reduced Complexity Turbo Multi User Detection for a CDMA Sys...

Experimental and Numerical Investigation of Cold Bulge Forming of Titanium Alloy Ti55

2006 10th International Conference on Communication Technology（ICCT 2006）

作者： Behrad mahboobi Said Nader-esfahani School of Electrical and Computer Engineering University of TehranTehran Iran

In CDmA systems, turbo multi user detection for multiple access interference cancellation and channel decoding in CDmA systems has an exponentially growing complexity with number of users. In these systems, when bandwidth efficient modulations like m-ary PSK are used another exponential factor that is relates to the levels of modulation prohibitively increases the computational complexity of the receiver. In this paper we have examined a symbol based reduced complexity multi user detector, for coded and un-coded CDmA system, with a performance very near to optimal detector while having extremely low complexity. We have introduced a design formula for the required Hamming distance value for no loss in performance. Simulation results of coded and un-coded CDmA system verify the performance of our reduced complexity detector that we expect.

关键词： Turbo multi user non-binary PSK convulutional code Reduced complexity Hamming distance.

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World Journal of mechanics 2013年第9期3卷 323-327页

作者： S. m. R. Tabatabaei m. Safari R. Shahrokh esfahani A. Abolghasemian. Sichani m. Nourjani Pour moghadam Department of mechanical Engineering Amir Kabir University of Technology Tehran Iran Department of mechanical Engineering Isfahan University of Technology Isfahan Iran Department of mechanical Engineering Khomeinishahr Branch Islamic Azad University Isfahan Iran Department of mechanical Engineering Razi University of Kermanshah Kermanshah Iran

In this paper, cold bulge forming of titanium alloy Ti55 was investigated. This process was done successfully and titanium alloy Ti55 was formed completely. Also, in the numerical work, this process has been investigated using Abaqus/ Explicit code. The results show that there is a good agreement between experimental and numerical results. mechanical properties of Titanium alloy Ti55 have been investigated before and after bulge forming. The results show that mechanical properties of titanium alloy Ti55 have been improved during bulge forming. Also, hardness, and thickness variation tests of sheet metal before and after bulge forming were performed and the same results to mechanical properties were obtained.

关键词： Cold Bulge Forming Titanium Alloy Ti55 Abaqus/Explicit

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FRP增强钢筋混凝土梁损伤的振动监测

钢结构(中英文) 2009年第6期 85-86页

作者： Neda Baghiee m.Reza esfahani Kazem moslem

采用试验数据,识别钢筋混凝土梁模态。对9个混凝土梁的破坏过程和动态参数进行监测,当荷载到达预期破坏荷载一半时,对6个梁采用外贴碳纤维布进行加固。基于所测模态参数,对识别方法进行研究并对识别方法的效率进行分析。这些方法包括频... 详细信息

采用试验数据,识别钢筋混凝土梁模态。对9个混凝土梁的破坏过程和动态参数进行监测,当荷载到达预期破坏荷载一半时,对6个梁采用外贴碳纤维布进行加固。基于所测模态参数,对识别方法进行研究并对识别方法的效率进行分析。这些方法包括频率变化、模态确证准则(mAC)、坐标模态确证准则(COmAC)和模态曲率。通过比较这些方法可知,频率变化不能完全监测损伤以及预测加固的潜力;模态确证准则的值能够揭示荷载变化过程中梁的刚度变化;对梁每个自由度的刚度变化可采用坐标模态确证准则进行评估;模态曲率方法是对梁进行损伤识别的最好方法。

关键词：损伤纤维增强复合材料模型试验钢筋混凝土加固

Comparison of the predictive value of the Helsinki,Rotterdam,and Stockholm CT scores in predicting 6-month outcomes in patients with blunt traumatic brain injuries

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Chinese Journal of Traumatology 2023年第6期26卷 357-362页

作者： Nushin moussavi Biuki Hamid Reza Talari mohammad Hossein Tabatabaei masoumeh Abedzadeh-Kalahroudi Hossein Akbari mahsa masjedi esfahani Reihaneh Faghihi Department of Surgery Trauma Research CenterKashan University of Medical SciencesKashanIran Department of Radiology Kashan University of Medical SciencesKashanIran Trauma Research Center Kashan University of Medical SciencesKashanIran Department of Biostatistics Trauma Research CenterKashan University of Medical SciencesKashanIran

Purpose:Despite advances in modern medicine,traumatic brain injuries(TBIs)are still a major medical *** diagnosis of TBI is crucial for clinical decision-making and *** study aims to compare the predictive value of Helsinki,Rotterdam,and Stockholm CT scores in predicting the 6-month outcomes in blunt TBI ***:This cohort study was conducted on blunt TBI patients of 15 years or *** of them were admitted to the surgical emergency department of Shahid Beheshti Hospital in Kashan,Iran from 2020 to 2021 and had abnormal trauma-related findings on brain CT *** patients’demographic data such as age,gender,history of comorbid conditions,mechanism of trauma,Glasgow coma scale,CT images,length of hospital stay,and surgical procedures were *** Helsinki,Rotterdam,and Stockholm CT scores were simultaneously determined according to the existing *** included patients'6-month outcome was determined using the Glasgow outcome scale extended.m Data were analyzed by SPSS software version ***,specificity,negative/positive predictive value and the area under the receiver operating characteristic curve were calculated for each *** Kappa agreement coefficient and Kuder Richardson-20 were used to compare the scoring ***:Altogether 171 TBI patients met the inclusion and exclusion criteria,with the mean age of(44.9±20.2)*** patients were male(80.7%),had traffic related injuries(83.1%)and mild TBIs(64.3%).Patients with lower Glasgow coma scale had higher Helsinki,Rotterdam,and Stockholm CT scores and lower Glasgow outcome scale extended *** all the scoring systems,the Helsinki and Stockholm scores showed the highest agreement in predicting patients’outcomes(kappa=0.657,pm scoring system had the highest sensitivity(90.1%)in predicting death of TBI patients,whereas the Helsinki scoring system had the highest sensitivity(89.8%)in predicting the 6-month outcome in TBI

关键词： Brain injuries,traumatic Traumatic Rotterdam CT scoring system Helsinki CT scoring system Stockholm CT scoring system CT scan Glasgow outcome scale extended

microfabricated platforms to investigate cell mechanical properties

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medicine in Novel Technology and Devices 2022年第1期13卷 49-58页

作者： Amir m.esfahani Grayson minnick Jordan Rosenbohm Haiwei Zhai Xiaowei Jin Bahareh Tajvidi Safa Justin Brooks Ruiguo Yang Department of mechanical and materials Engineering University of Nebraska-LincolnLincolnNE68516USA Nebraska Center for Integrated Biomolecular Communication University of Nebraska-LincolnLincolnNE68588USA mary and Dick Holland Regenerative medicine Program University of Nebraska Medical CenterOmahaNE68198USA Department of Bioengineering School of MedicineJohns Hopkins UniversityBaltimoreMD21205USA

mechanical stimulation has been imposed on living cells using several *** early investigations were conducted on groups of cells,utilizing techniques such as substrate deformation and flow-induced *** investigate the properties of cells individually,many conventional techniques were utilized,such as AFm,optical traps/optical tweezers,magnetic beads,and micropipette *** specific mechanical interrogations,microelectro-mechanical systems(mEmS)have been designed to probe single cells in different interrogation *** exert loads on the cells,these devices often comprise piezo-electric driven actuators that attach directly to the cell or move a structure on which cells are *** and biaxial pullers,micropillars,and cantilever beams are examples of mEmS *** this review,the methodologies to analyze single cell activity under external loads using microfabricated devices will be *** will focus on the mechanical interrogation in three different regimes:compression,traction,and tension,and discuss different microfabricated platforms designed for these purposes.

关键词： BiomEmS Single cell mechanical properties microdevices

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碳纤维布加固钢筋混凝土梁的弯曲性能

钢结构(中英文) 2008年第5期 71-71页

作者： m.R. esfahani m.R. Kianoush A.R. Tajari

对采用碳纤维布加固的钢筋混凝土梁的弯曲性能进行研究。考察了配筋率ρ对加固梁弯曲强度的影响。对12个混凝土梁试件(截面尺寸为宽150mm,高200mm,长2000mm)进行了试验。梁截面具有三种不同的纵向钢筋配筋率,9个试件在受弯区域采用碳纤... 详细信息

对采用碳纤维布加固的钢筋混凝土梁的弯曲性能进行研究。考察了配筋率ρ对加固梁弯曲强度的影响。对12个混凝土梁试件(截面尺寸为宽150mm,高200mm,长2000mm)进行了试验。梁截面具有三种不同的纵向钢筋配筋率,9个试件在受弯区域采用碳纤维布加固,另外3个试件作为对比试件。不同试件中,碳纤维布的宽度、长度和层数是变化的。与对比试件相比,加固梁的弯曲强度和刚度增加了。从研究结果可得出,与最大配筋率的梁相比,ACI440·2R-02的设计指南和加拿大的I-SIS高估了碳纤维布在小配筋率梁的弯曲强度方面的增加作用。随着梁的配筋率ρ的增长,试验荷载与按照ACI440·2R-02指南和加拿大ISIS计算荷载的比值是增长的。因此,由两个设计指南提出的方程更适合于高配筋率的梁,接近最大配筋率ρmax的梁试件的破坏具有足够的延性。

关键词：碳纤维增强复合材料弯曲强度配筋率钢筋混凝土梁