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Elevated temperature oxidation behavior of HVOF sprayed TiB_2 cermet coating

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Transactions of Nonferrous Metals Society of China 2010年第2期20卷 243-247页

作者： behnam LOTFI Department of Materials Engineering Faculty of EngineeringShahid Chamran UniversityAhvazIran

Oxidation behaviors of Ni(Cr)-TiB2 coating deposited by HVOF technique were studied at 800,900 and 1 000℃in air. The microstructures of as-sprayed and oxidized coatings were characterized by X-ray diffractometry(XRD)and scanning electron microscopy(SEM).After oxidation at 800℃,a thin and adherent oxide layer was formed on the surface of the *** increasing exposure temperature,the thickness of the oxide layer increased;and at 1 000℃the oxide layer separated from the *** of the kinetics of oxidation by using the thermogravimetric analysis(TGA)technique shows a parabolic oxidation rate.

关键词： TiB2 cermet coating thermal spraying oxidation

Empirical models and design codes in prediction of modulus of elasticity of concrete

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Frontiers of Structural and Civil Engineering 2019年第1期13卷 38-48页

作者： behnam VAKHSHOURI Shami NEJADI Centre for Built Infrastructure Research University of Technology SydneySydneyAustralia

Modulus of Elasticity (MOE)is a key parameter in reinforced concrete *** represents the stressstrain relationship in the elastic range and is used in the prediction of concrete *** of range estimation of MOE in the existing codes of practice strongly affect the design and performance of the concrete *** study includes: (a)evaluation and comparison of the existing analytical models to estimating the MOE in normal strength concrete,and (b)proposing and verifying a new *** addition,a wide range of experimental databases and empirical models to estimate the MOE from compressive strength and density of concrete are evaluated to verification of the proposed model. The results show underestimation of MOE of conventional concrete in majority of the existing ***,considering the consistency between density and mechanical properties of concrete,the predicted MOE in the models including density effect,are more compatible with the experimental results.

关键词： modulus of elasticity normal strength normal weight concrete empirical models design codes compressive strength density

Performance-based semi-active control algorithm for protecting base isolated buildings from near-fault earthquakes

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Earthquake Engineering and Engineering Vibration 2012年第1期11卷 43-55页

作者： behnam Mehrparvar Taramarz Khoshnoudian Department of Civil Engineering West Tehran Branch Islamic Azad University Department of Civil Engineering Amirkabir University of Technology

Base isolated structures have been found to be at risk in near-fault regions as a result of long period pulses that may exist in near-source ground motions. Various control strategies, including passive, active and semi-active control systems, have been investigated to overcome this problem. This study focuses on the development of a semi-active control algorithm based on several performance levels anticipated from an isolated building during different levels of ground shaking corresponding to various earthquake hazard levels. The proposed performance-based algorithm is based on a modified version of the well-known semi-active skyhook control algorithm. The proposed control algorithm changes the control gain depending on the level of shaking imposed on the structure. The proposed control system has been evaluated using a series of analyses performed on a base isolated benchmark building subjected to seven pairs of scaled ground motion records. Simulation results show that the newly proposed algorithm is effective in improving the structural and nonstructural performance of the building for selected earthquakes.

关键词： structural control active control semi-active control base isolation

Microstructure and Sliding Wear Behaviour of Ni(Cr)-TiB_2 Coatings Deposited by HVOF Spraying of SHS Powders

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材料热处理学报 2004年第5B期25卷 1183-1186页

作者： behnam Lotfi Zohreh Sadeghian Faculty of Engineering Department of Materials Engineering Shahrecord University Shahrecord IranDepartment of Materials Science and Engineering Isfahan University of Technology Isfahan Iran

This work reports research concerning the microstructure and sliding wear behaviour of cermet coatings deposited by high velocity oxy-fuel (HVOF) spraying. Two cermets were prepared with the following target compositions namely, Ni (Cr)-65 wt.% TiB2 and Ni (Cr)-40 wt.% TiB2. Coating microstructures were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD), whilst microhardness and sliding wear tests were performed on the coatings to evaluate their performance. The HVOF sprayed deposits had layered, splat-like morphologies typical of thermally sprayed cermets. Coatings consisted primarily of TiB2 particles in a nickel-based binder phase. Other minor peaks in the XRD patterns belong to TiB, Ni2B, NiTiO3 and Ti2Oj. The coatings exhibit an amorphous halo in the diffraction pattern between 2 values of 40° and 50°. Sliding wear behaviour was examined using a conventional ball-on-disc apparatus. A sintered ceramic ball (A12O3) was employed as the counterface. The Ni (Cr)-65 wt.% TiB2 coating had a lower wear rate than Ni (Cr)-40 wt.% TiB2 coating. This may be related to the larger sizes of borides. Wear scar morphologies, on both coatings were examined by using SEM and EDAX detecting in order to establish the wear mechanism. Wear is proposed to proceed by subsurface cracking in these coatings.

关键词：显微结构滑动磨损 SHS HVOF Ni(Cr)-TiB2合金

A Review on Plug-in Electric Vehicles:Introduction, Current Status, and Load Modeling Techniques

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Journal of Modern Power Systems and Clean Energy 2020年第3期8卷 412-425页

作者： Ali Ahmadian behnam Mohammadi-Ivatloo Ali Elkamel Department of Electrical Engineering University of BonabBonabIran Institute of Research and Development Duy Tan UniversityDa Nang 550000Vietnam College of Engineering Khalifa University of Science and Technologythe Petroleum InstituteAbu DhabiUnited Arab Emirates

Plug-in electric vehicle(PEV) load modeling is very important in the operation and planning studies of modern power system nowadays. Several parameters and considerations should be taken into account in PEV load modeling, making it a complex problem that should be solved using appropriate techniques. Different techniques have been introduced for PEV load modeling and each of them has individual specifications and features. In this paper, the most popular techniques for PEV load modeling are reviewed and their capabilities are evaluated. Both deterministic and probabilistic methods are investigated and some practical and theoretical hints are presented. Moreover, the characteristics of all techniques are compared with each other and suitable methods for unique applications are proposed. Finally, some potential research areas are presented for future works.

关键词： Plug-in electric vehicles load modeling deterministic and probabilistic techniques distribution networks

Morphological peculiarities of the lithium electrode from the perspective of the Marcus-Hush-Chidsey model

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Journal of Energy Chemistry 2023年第5期80卷 452-457,I0011页

作者： behnam Ghalami Choobar Hamid Hamed Mohammadhosein Safari Institute for Materials Research(IMO-imomec) UHasseltMartelarenlaan 42B-3500 HasseltBelgium Energyville Thor Park 8320B-3600 GenkBelgium IMEC Division IMOMEC BE-3590Belgium

This study employs the kinetics framework of Marcus-Hush-Chidsey(MHC)to investigate the charge transfer at the interface of lithium electrode and electrolyte in lithium(ion)-*** chargetransfer rate constant is evaluated for different facets of lithium,namely(100),(110),(101),and(111)as a function of surface charge density with the aid of density functional theory(DFT)*** results highlight and quantify the sensitivity of the rate of lithium plating and stripping to the surface orientation,surface charge density,and charge-transfer *** intrinsic kinetics competition among the different surface orientations is identified together with an asymmetry between the lithium plating and stripping and showcased to influence the deposit morphology and surface protrusions and indentations.

关键词： Marcus-Hush-Chidsey kinetics Surface orientation Surface charge Lithium electrode

Microstructural characteristics and mechanical properties of Al-2024 alloy processed via a rheocasting route

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International Journal of Minerals,Metallurgy and Materials 2015年第1期22卷 59-67页

作者： behnam Rahimi Hamed Khosravi Mohsen Haddad-Sabzevar Department of Metallurgy and Materials Engineering Faculty of EngineeringFerdowsi University of Mashhad Faculty of Materials Science and Engineering K.N.Toosi University of Technology

This article reports the effects of stirring speed and T6 heat treatment on the microstructure and mechanical properties of Al-2024 alloy synthesized by a rheocasting process. There was a decrease in grain size ofα-Al particles corresponding to an increase in stirring speed. By increasing the stirring speed, however, the globularity of matrix particles first increased and then declined. It was also found that the hardness, compressive strength, and compressive strain increased with the increase of stirring speed. Microstructural studies revealed the presence of nonsoluble Al15（CuFeMn）3Si2 phase in the vicinity of CuAl2 in the rheocast samples. The required time for the solution treatment stage was also influenced by stirring speed;the solution treatment time decreased with the increase in stirring speed. Furthermore, the rheo-cast samples required a longer homogenization period compared to conventionally wrought alloys. Improvements in hardness and compres-sive properties were observed after T6 heat treatment.

关键词： aluminum alloys rheocasting microstructure mechanical properties

Seismic progressive-failure analysis of tall steel structures under beam-removal scenarios

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Frontiers of Structural and Civil Engineering 2019年第4期13卷 904-917页

作者： Behrouz behnam Fahimeh SHOJAEI Hamid Reza RONAGH School of Civil and Environmental Engineering Amirkabir University of Technology Tehran 13496 Iran Independent Researcher Earthquake Engineer Parand 37611 Iran Centre for Infrastructure Engineering Western Sydney University NSW 2751 Australia

Investigating progressive collapse of tall structures under beam removal scenarios after earthquake is a complex subject because the earthquake damage acts as an initial condition for the subsequent scenario. An investigation is performed here on a 10 story steel moment resisting structure designed to meet the life safety level of performance when different beam removal scenarios after earthquake are considered. To this end, the structure is first subjected to the design earthquake simulated by Tabas earthquake acceleration. The beam removal scenarios are then considered at different locations assuming that both ends connections of the beam to columns are simultaneously detached from the columns;thus the removed beam falls on the underneath floor with an impact. This imposes considerable loads to the structure leading to a progressive collapse in all the scenarios considered. The results also show that the upper stories are much more vulnerable under such scenarios than the lower stories. Hence, more attention shall be paid to the beam-to-column connections of the upper stories during the process of design and construction.

关键词： progressive collapse tall steel moment-resisting frames non-linear dynamic analysis beam-removal scenario impact

Chemical-only reprogramming to pluripotency

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Frontiers in Biology 2016年第2期11卷 75-84页

作者： behnam Ebrahimi Yazd Cardiovascular Research Center Shahid Sadoughi University of Medical Sciences Yazd Iran

Direct reprogramming technology has emerged as an outstanding technique for the generation of induced pluripotent stem cells （iPSCs） and various specialized cells directly from somatic ceils of different species. Reprogramming techniques conventionally use viral vectors encoding transcription factors to induce fate conversion. However, the introduction of transgenes limits the therapeutic applications of the reprogrammed cells. To overcome safety-related concerns, small molecules offer some advantages over the existing methods for the control of gene expression and induction of cell fate conversion. Technical advances in optimizing concentrations, durations, structures, and combinations of small molecules make chemical reprogramming a safe and feasible method. This review provides a concise overview of cutting-edge findings regarding chemical-only reprogramming as one of the integration-free approaches to iPSC generation.

关键词： cellular reprogramming small molecule chemical reprogramming induced pluripotency regenerative medicine