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mechanical Properties of V-,Nb-,and Ti-bearing As-cast microalloyed Steels

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Journal of materials Science & Technology 2007年第6期23卷 779-784页

作者： J.Rassizadehghani H.Najafi m.Emamy G.eslami-Saeen School of metallurgy and materials Engineering University College of EngineeringUniversity of TehranP.O.Box 14395-731TehranIran

The influence of microalloying additions on the mechanical properties of a low-carbon cast steel containing combinations of V, Nb, and Ti in the as-cast condition was evaluated. Tensile and hardness test results indicated that good combinations of strength and ductility could be achieved by V and Nb additions. While the yield strength and UTS （ultimate tensile strength） increased up to the range of 378-435 mPa and 579- 590 mPa, respectively in the microalloyed heats, their total elongation ranged from 18% to 23%. The presence of Ti, however, led to some reduction in the strength. microstructural studies including scanning electron microscopy （SEm） and optical microscopy revealed that coarse TiN particles were responsible for this behavior. The Charpy impact values of all compositions indicated that microalloying additions significantly decreased the impact energy and led to the dominance of cleavage facets on the fracture surfaces. It seems that the increase in the hardness of coarse ferrite grains due to the precipitation hardening is the main reason for brittle fracture.

关键词： Cast steel microalloyed steel Titanium Niobium Vanadium

Occurrence mechanism of silicate and aluminosilicate minerals in Sarcheshmeh copper flotation concentrate

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International Journal of minerals,metallurgy and materials 2009年第5期16卷 494-499页

作者： H.R.Barkhordari1 E.Jorjani1 A.eslami m.Noaparast mining Engineering Department Science and Research BranchIslamic Azad UniversityPoonakHesarakTehranIran R&D Division-Sarcheshmeh Copper Complex RafsanjanIran School of mining Engineering University College of EngineeringUniversity of TehranTehranIran

The Sarcheshmeh copper flotation circuit is producing 5× 10^4 t copper concentrate per month with an averaging grade of 28% Cu in rougher, cleaner and recleaner stages. In recent years, with the increase in the open pit depth, the content of aluminosilicate minerals increased in plant feed and subsequently in flotation concentrate. It can motivate some problems, such as unwanted consumption of reagents, decreasing of the copper concentrate grade, increasing of Al2O3 and SiO2 in the copper concentrate, and needing a higher temperature in the smelting process. The evaluation of the composite samples related to the most critical working period of the plant shows that quartz, illite, biotite, chlorite, orthoclase, albeit, muscovite, and kaolinite are the major Al2O3 and SiO2 beating minerals that accompany chalcopyrite, chalcocite, and covellite minerals in the plant feed. The severe alteration to clay minerals was a general rule in all thin sections that were prepared from the plant feed. Sieve analysis of the flotation concentrate shows that Al2O3 and SiO2 bearing minerals in the flotation concentrate can be decreased by promoting the size reduction from 53 to 38 μm. Interlocking of the Al2O3 and SiO2 bearing minerals with chalcopyrite and chalcocite is the occurrence mechanism of silicate and aluminosilicate minerals in the flotation concentrate. The dispersed form of interlocking is predominant.

关键词： copper aluminosilicate silicate flotation

Power system stabilizer design using hybrid multi-objective particle swarm optimization with chaos

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Journal of Central South University 2011年第5期18卷 1579-1588页

作者： mahdiyeh eslami Hussain Shareef Azah mohamed Electrical Engineering Department Islamic Azad University (SRBIAU)HesarakTehranIran Electrical Electronic and Systems Engineering DepartmentUniversity Kebangsaan MalaysiaBangi43600SelangorMalaysia

A novel technique for the optimal tuning of power system stabilizer (PSS) was proposed,by integrating the modified particle swarm optimization (mPSO) with the chaos (mPSOC).Firstly,a modification in the particle swarm optimization (PSO) was made by introducing passive congregation (PC).It helps each swarm member in receiving a multitude of information from other members and thus decreases the possibility of a failed attempt at detection or a meaningless ***,the mPSO and chaos were hybridized (mPSOC) to improve the global searching capability and prevent the premature convergence due to local *** robustness of the proposed PSS tuning technique was verified on a multi-machine power system under different operating *** performance of the proposed mPSOC was compared to the mPSO,PSO and GA through eigenvalue analysis,nonlinear time-domain simulation and statistical *** analysis shows acceptable damping of the low-frequency modes and time domain simulations also show that the oscillations of synchronous machines can be rapidly damped for power systems with the proposed *** results show that the presented algorithm has a faster convergence rate with higher degree of accuracy than the GA,PSO and mPSO.

关键词： passive congregation chaos power system stabilizer penalty function particle swarm optimization

A new hybrid algorithm for global optimization and slope stability evaluation

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Journal of Central South University 2013年第11期20卷 3265-3273页

作者： Taha mohd Raihan Khajehzadeh mohammad eslami mahdiyeh Civil and Structural Engineering Department National University of Malaysia Civil Engineering Department Anar BranchIslamic Azad University Electrical Engineering Department Science and Research BranchIslamic Azad University

A new hybrid optimization algorithm was presented by integrating the gravitational search algorithm （GSA） with the sequential quadratic programming （SQP）, namely GSA-SQP, for solving global optimization problems and minimization of factor of safety in slope stability analysis. The new algorithm combines the global exploration ability of the GSA to converge rapidly to a near optimum solution. In addition, it uses the accurate local exploitation ability of the SQP to accelerate the search process and find an accurate solution. A set of five well-known benchmark optimization problems was used to validate the performance of the GSA-SQP as a global optimization algorithm and facilitate comparison with the classical GSA. In addition, the effectiveness of the proposed method for slope stability analysis was investigated using three ease studies of slope stability problems from the literature. The factor of safety of earth slopes was evaluated using the morgenstern-Price method. The numerical experiments demonstrate that the hybrid algorithm converges faster to a significantly more accurate final solution for a variety of benchmark test functions and slope stability problems.

关键词： gravitational search algorithm sequential quadratic programming hybrid algorithm global optimization slope stability

Are women more susceptible to ischemic heart disease compared to men? A literature overview

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Journal of Geriatric Cardiology 2021年第4期18卷 289-296页

作者： masoud majidi Vahid eslami Pardis Ghorbani mahnoosh Foroughi Clinical Research and Development Center Shahid Modarres HospitalShahid Beheshti University of Medical SciencesTehranIran Cardiovascular Research Center Shahid Beheshti University of Medical SciencesTehranIran

Ischemic heart disease(IHD) is known as the leading cause of death in both genders. moreover, significant sex differences were found in cardiac structure, function, pathophysiology, presentation, treatment, and outcome of IHD. The presence of unique risk factors such as exposure to menarche and pregnancy, more anemia, hypertension, and autoimmune disorders in women have recently received attention. Ischemic symptoms are more indefinite and vague in women compared to men as well as a delay in diagnosis, treatment, and worse outcomes compared to men. Women usually receive less evidence-based treatment and intervention, with less concern on preventive health care. Clinical trials primarily recruit male patients and women are underrepresented. Without any correct diagnosis, treatment, and prevention, these problems are accumulated and continue up to older age. Accordingly, with the belief of longer life in women and the increased prevalence of IHD with aging, it will become an important public health problem and concern in the future. This narrative review aimed to provide an overview of some of the differences between the two genders in terms of IHD with paying more attention to practical points.

关键词： IHD presentation A literature overview Are women more susceptible to ischemic heart disease compared to men

Comparison of Artificial Neural Networks,Geographically Weighted Regression and Cokriging methods for Predicting the Spatial Distribution of Soil macronutrients(N,P,and K)

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Chinese Geographical Science 2017年第5期27卷 747-759页

作者： Samad EmAmGHOLIZADEH Shahin SHAHSAVANI mohamad Amin eslami 1.Department of Water and Soil Engineering Shahrood University of TechnologyShahrood361999-5161Iran

Soil macronutrients(i.e. nitrogen(N), phosphorus(P), and potassium(K)) are important soils components and knowing the spatial distribution of these parameters are necessary at precision agriculture. The purpose of this study was to evaluate the feasibility of different methods such as artificial neural networks(ANN) and two geostatistical methods(geographically weighted regression(GWR) and cokriging(CK)) to estimate N, P and K contents. For this purpose, soil samples were taken from topsoil(0–30 cm) at 106 points and analyzed for their chemical and physical parameters. These data were divided into calibration(n = 84) and validation(n = 22). Chemical and physical variables including clay, p H and organic carbon(OC) were used as auxiliary soil variables to estimate the N, P and K contents. Results showed that the ANN model(with coefficient of determination R^2 = 0.922 and root mean square error RmSE = 0.0079%) was more accurate compared to the CK model(with R^2 = 0.612 and RmSE = 0.0094%), and the GWR model(with R^2 = 0.872 and RmSE = 0.0089%) to estimate the N variable. The ANN model estimated the P with the RmSE of 3.630 ppm, which was respectively 28.93% and 20.00% less than the RmSE of 4.680 ppm and 4.357 ppm from the CK and GWR models. The estimated K by CK, GWR and ANN models have the RmSE of 76.794 ppm, 75.790 ppm and 52.484 ppm. Results indicated that the performance of the CK model for estimation of macro nutrients(N, P and K) was slightly lower than the GWR model. Also, the accuracy of the ANN model was higher than CK and GWR models, which proved to be more effective and reliable methods for estimating macro nutrients.

关键词： precision agriculture soil characteristics interpolation artificial neural networks geographically weighted regression Cokriging

Reply to Discussion on “Empirical methods for determining shaft bearing capacity of semi-deep foundations socketed in rocks”

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Journal of Rock mechanics and Geotechnical Engineering 2018年第3期10卷 607-609页

作者： S.Rezazadeh A.eslami Department of Civil and Environmental Engineering Amirkabir University of Technology

Semi-deep foundations socketed in rocks are considered to be a viable option for the foundations in the presence of heavy loads imposed by high-rise buildings and special structures, due to the low settlement and high bearing capacity. In this study, the unconfined compressive strength（UCS） and rock mass cuttability index（RmCI） have been applied to investigating the shaft bearing capacity. For this purpose, a comprehensive database of 178 full-scale load tests is compiled by adding a data set（n = 72）collected by Arioglu et al.（2007） to the data set（n = 106） presented in Rezazadeh and eslami（2017）.Using the database, the applicability and accuracy of the existing empirical methods are evaluated and new relations are derived between the shaft bearing capacity and UCS/RmCI. moreover, a general equation in case of unknown rock types is proposed and it is verified by another set of data（series 3 in Rezazadeh and eslami（2017））. Since rock-socketed shafts are supported by rock mass（not intact rock）,a reduction factor for the compressive strength is suggested and verified in which the effect of discontinuities is considered using the modified UCS, based upon RmR and RQD to consider the effect of the rock mass properties.

关键词： Shaft bearing capacity Semi-deep foundations Database Unconfined compressive strength (UCS) Rock mass cuttability index (RmCI)

Nonlinear forced vibration in a subcritical regime of a porous functionally graded pipe conveying fluid with a retaining clip

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Applied mathematics and mechanics(English Edition) 2025年第1期46卷 101-122页

作者： m.GHOLAmI m.EFTEKHARI Department of mechanical Engineering Shahid Bahonar University of Kerman

This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGm) that conveys fluids and is equipped with a retaining clip, focusing on primary resonance and subcritical dynamics. The nonlinear governing equations for the FGm pipe are derived by the extended Hamilton's principle, and subsequently discretized through the application of the Galerkin *** direct method of multi-scales is then used to solve the derived equations. A thorough analysis of various parameters, including the clip stiffness, the power-law index, the porosity, and the clip location, is conducted to gain a comprehensive understanding of the system's nonlinear dynamics. Through the analysis of the first natural frequency, the study highlights the influence of the flow velocity and the clip stiffness, while the comparisons with metallic pipes emphasize the role of FGm composition. The examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index, offering valuable insights into the system's nonlinear resonant behavior. Furthermore, the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness, revealing nuanced effects on the system response and resonance characteristics. This comprehensive analysis enhances the understanding of nonlinear behaviors in FGm porous pipes with a retaining clip, providing key insights for practical engineering applications in system design and optimization.

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modified particle swarm optimization for optimum design of spread footing and retaining wall

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第6期12卷 415-427页

作者： mohammad KHAJEHZADEH mohd Raihan TAHA Ahmed EL-SHAFIE mahdiyeh eslami Department of Civil Engineering Anar BranchIslamic Azad University Department of Civil and Structural Engineering University Kebangsaan Malaysia Department of Electrical Engineering Anar BranchIslamic Azad University

This paper deals with the economically optimized design and sensitivity of two of the most widely used systems in geotechnical engineering: spread footing and retaining wall. Several recent advanced optimization methods have been developed, but very few of these methods have been applied to geotechnical problems. The current research develops a modified particle swarm optimization (mPSO) approach to obtain the optimum design of spread footing and retaining wall. The algorithm handles the problem-specific constraints using a penalty function approach. The optimization procedure controls all geotechnical and structural design constraints while reducing the overall cost of the structures. To verify the effectiveness and robustness of the proposed algorithm, three case studies of spread footing and retaining wall are illustrated. Comparison of the results of the present method, standard PSO, and other selected methods employed in previous studies shows the reliability and accuracy of the algorithm. moreover, the parametric performance is investigated in order to examine the effect of relevant variables on the optimum design of the footing and the retaining structure utilizing the proposed method.

关键词： Particle swarm optimization (PSO) Spread footing Retaining wall Sensitivity analysis