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Chinese Journal of Aeronautics 2010年第4期23卷 409-414页

作者： Ali kamran School of Astronautics Beijing University of Aeronautics and Astronautics

Upper stage solid rocket motors （SRMS） for launch vehicles require a highly efficient propulsion system. Grain design proves to be vital in terms of minimizing inert mass by adopting a high volumetric efficiency with minimum possible sliver. In this arti- cle, a methodology has been presented for designing three-dimensional （3D） grain configuration of radial slot for upper stage solid rocket motors. The design process involves parametric modeling of the geometry in computer aided design （CAD） software through dynamic variables that define the complex configuration. Grain bum back is achieved by making new surfaces at each web increment and calculating geometrical properties at each step. Geometrical calculations are based on volume and change-in-volume calculations. Equilibrium pressure method is used to calculate the internal ballistics. Genetic algorithm （GA） has been used as the optimizer because of its robustness and efficient capacity to explore the design space for global optimum solution and eliminate the requirement of an initial guess. Average thrust maximization under design constraints is the objective function.

关键词： solid rocket motors 3D grains radial slot configuration internal ballistics computer aided design heuristic optimization genetic algorithm

Electro-optomechanical switch via tunable bistability and four-wave mixing

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Chinese Physics B 2019年第11期28卷 193-203页

作者： kamran Ullah Department of Physics Quaid-i-Azam University

We investigate the tunable bistable behavior of a hybrid nano-electro-optomechanical system(NEOMS) composed of S-shaped in the presence of two-level atoms, trapped inside a Fabry–Pérot cavity, and driven by a strong driving field and a weak probe field. The bistable behavior of the steady-state photon number and the mechanical steady-state positions are discussed. Further, we tune bistability by tuning all the coupling frequencies involved in the system and amplitude of the driving field. The present study provides the possibility of realization of a controllable optical switch depending on atom-field coupling, optomechanical coupling, electrostatic Coulomb coupling, and threshold power. In addition, we discuss that the non-linear effect of the hybrid NEOMS generates the four-wave mixing(FWM) process. Moreover, we show that the FWM process can be suppressed by the atom-field detuning and cavity-field detuning, which exhibits low photon transmission.

关键词： nano-electro-optomechanics nano-resonators two-level atom optical switch optical bistability four-wave mixing

An improved porous media model for nuclear reactor analysis

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Nuclear Science and Techniques 2016年第1期27卷 117-140页

作者： Roozbeh Vadi kamran Sepanloo Schools of Nuclear Safety Research and Radiation Protection Nuclear Science and Technology Research InstituteEnd of North Karegar Ave.P.O.Box:14359-836TehranIran

In this study, two modifications are proposed to mitigate drawbacks of the conventional approach of using the ‘‘Porous Media Model''(PMM) for nuclear reactor analysis. In the conventional approach, whole reactor core simplifies to a single porous medium and also, the resistance coefficients that are essential to using this model are constant values. These conditions impose significant errors and restrict the applications of the model for many cases,including accident analysis. In this article, the procedures for calculating the coefficients are modified by introducing a practical algorithm. Using this algorithm will result in obtaining each coefficient as a function of mass flow ***, the method of applying these coefficients to the reactor core is modified by dividing the core into several porous media instead of one. In this method, each porous medium comprises a single fuel assembly. PMM with these two modifications is termed ‘‘multi-region PMM'' in this study. Then, the multi-region PMM is introduced to a new CFD-based thermo-hydraulic code that is specifically devised for combining with neutronic *** CITVAP code, which solves multi-group diffusion equations, is the selected as the neutronic part for this study. The resulting coupled code is used for simulation of natural circulation in a MTR. A new semi-analytic method,based on steady-state CFD analysis is developed to verify the results of this case. Results demonstrate considerable improvement, compared to the conventional approach.

关键词：多孔介质模型模型分析反应器传统方法应用程序流体力学分析稳态计算 PMM

Microstructural Evolution of NiTi47.7Cu6.3 Alloy during Hot Deformation

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Journal of Materials Science & Technology 2011年第10期27卷 951-960页

作者： Amir Etaati kamran Dehghani Mining and Metallurgical Eng.Dept. Amirkabir Univ.Tech.

In the present work, the hot workability and microstructural evolution of ***6.3 （at.%） shape memory alloy were investigated by using wedge-rolling test. The wedge specimens were subjected to hot rolling at the temperatures of 700-1000℃. The microstructural evolutions at the strains of 0.05, 0.15, 0.2, 0.25 and 0.3 were then characterized by optical microscopy and scanning electron microscopy （SEM） as well as energy dispersive spectrometry （EDS） technique. Depending on the deformation temperature and strain, the dynamic recrystallization （DRX） could occur, leading to the refining of the microstructure. At low temperatures of 700 and 800℃ there was no sign of DRX at all studied strains. At these temperatures, the formed fine needle-like precipitates pinned the grain boundaries and prevented them from bulging/migration. By contrast, at higher temperatures of 900 and 1000℃, the DRX took place at the critical strains lower than 0.25 and 0.15, respectively. However, at higher temperatures, strain-induced-boundary-migration （SIBM） mechanism resulted in the formation of DRX grains.

关键词： Deformation Wedge rolling test Dynamic recrystallization Ni-rich Nitinol NiTiCu

Influence of welding speed on corrosion behaviour of friction stir welded AA5086 aluminium alloy

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Journal of Central South University 2016年第6期23卷 1301-1311页

作者： kamran Amini Farhad Gharavi Department of Mechanical Engineering Tiran Branch Islamic Azad University

The plates of AA5086 aluminium alloy were joined together by friction stir welding at a fixed rotation speed of 1000 r/min various welding speeds ranging from 63 to 100 mm/*** behavior of the parent alloy(PA),the heat affected zone(HAZ),and the weld nugget zone(WNZ)of the joints were studied in 3.5%(mass fraction)aerated aqueous Na Cl solution by potentiodynamic polarization and electrochemical impedance spectroscopy(EIS).The corrosion susceptibility of the weldments increases when the welding speed increases to 63 and 100 mm/***,the value of corrosion rate in the weldments is lower than that in the ***,the corrosion current density increases with increasing the welding speed in the HAZ and the *** the contrary,the corrosion potential in the WNZ appears more positive than in the HAZ with decreasing the welding *** WNZ exhibits higher resistance compared to the HAZ and the PA as the welding speed *** results obtained from the EIS measurements suggest that the weld regions have higher corrosion resistance than the parent *** increasing the welding speed,the distribution and extent of the corroded areas in the WNZ region are lower than those of the HAZ *** the HAZ region,in addition to the pits in the corroded area,some cracks can be seen around the corroded areas,which confirms that intergranular corrosion is formed in this *** alkaline localized corrosion and the pitting corrosion are the main corrosion mechanisms in the corroded areas within the weld *** pits are observed within the weld regions.

关键词： friction stir welding aluminum alloy corrosion properties welding speed

Numerical Modeling of the Stability of Horizontal Multidrain Oil Wells

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China Ocean Engineering 2015年第5期29卷 719-732页

作者： Ayub ELYASI kamran GOSHTASBI Faculty of Engineering Tarbiat Modares University

The stability of the horizontal multidrain wells is a crucial issue and several factors are involved in this matter, including in-situ stresses, magnitude and distribution as well as the mainbore trajectories. In this paper, this issue is evaluated by assuming different circumstances for the above mentioned factors, based on finite difference threedimensional modeling by using the finite difference numerical software, FLAC3 D. The stability of the mainbore and lateral branches is analyzed based on the Normalized Yielded Zone Area（NYZA） criterion, i.e. the ratio of the surrounding yielded cross-sectional area to the initial area of the well. Optimum mud pressures are obtained in the mainbore and lateral branches in different mainbore trajectories under three in-situ stress regimes. In addition, the stability of the junction where the lateral branches are bifurcated from the mainbore is assessed in those situations. The optimum trajectory of the mainbore, in which the junction has obtained the most stable condition, is selected in each stress regime. It was concluded that in the Normal Faulting（NF） stress regime, the mainbore and junction stability varies in relation to the mainbore trajectories, inversely. However, in the other two stress regimes, i.e. Strike Slip（SS） and Reverse Faulting（RF）, the variations of the mainbore and junction stability are in the same trend with respect to the mainbore trajectory deviations.

关键词： multidrain wells in-situ stresses NYZA mainbore lateral branches

Carbothermic Reduction of Zinc Oxide Concentrate by Microwave

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Journal of Materials Science & Technology 2005年第5期21卷 724-728页

作者： Ali Saidi kamran Azari Department of Materials Engineering Isfahan University of TechnologyIsfahan IranNaghsh-e-Jahan Steel Research Institute Isfahan Science and Technology Town IsfahanIran

Industrial application of microwave, as a heating source for material processing, was reviewed. The feasibility of carbothermic reduction of zinc oxide concentrate, as well as the effect of operating parameters was investigated, using a home style microwave oven at 2.45 GHz. Zinc oxide concentrate does not effectively absorb microwave energy, while any source of carbon, which is used as the reduction agent, absorbs microwave energy very well. In this respect coke breeze was found to be the best, and thus, coke was used both as the reducing agent and the absorbent of microwave energy. It was also found that any increase in the carbon content and size, increases the reduction rate. Increasing the microwave power and the size of the sample could also increase the reduction rate. Further investigation shows that when zinc oxide is exposed to the microwave for some time, the rate of the reduction by conventional method increases.

关键词： Microwave Zinc oxide Reduction

Hot Ductility of Severe Plastic Deformed AA6061 Aluminum Alloy

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Acta Metallurgica Sinica(English Letters) 2015年第3期28卷 322-330页

作者： Ali Akbar Khamei kamran Dehghani Mining and Metallurgical Engineering Department Amirkabir University of Technology

The hot ductility of 6061 aluminum alloy,which was subjected to two different severe plastic deformations（SPD）,was studied at different temperatures and strain *** tensile tests were carried out at the temperature range of 300-500 ℃ and at the strain rates of 0.0005-0.01 s^（-1）.The microstructure evolution was characterized using optical microscopy,transmission electron microscopy and X-ray diffraction *** influences of the microstructure after SPD,thermomechanical parameters（temperature and strain rate） and specimen size on the hot formability of this alloy were then *** results show that a decrease in grains/subgrains exhibited significant effect on the hot ductility of SPDed *** constitutive equations were then developed to model the hot formability of the studied *** developed model can be represented by Zener-Hollomon parameter in a hyperbolic sinusoidal equation *** the changes of elongation to failure and Zener-Hollomon parameter indicate that the hot ductility of the alloy is more sensitive to the temperature rather than to the strain *** uniform elongation is independent of the specimen size,but the postnecking elongation increases dramatically as the ratio of l/A^（1/2） decreases.

关键词： Al-Mg-Si alloy Deformation behavior Equal channel angular pressing(ECAP) Rolling Hot tensile deformation

Design and optimization of solid rocket motor Finocyl grain using simulated annealing

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航空动力学报 2011年第4期26卷 917-923页

作者： All kamran LIANG Guo-zhu School of Astronautics Beijing University of Aeronautics and Astronautics Beijing 100191 China

The research effort outlined the application of a computer aided design(CAD)-centric technique to the design and optimization of solid rocket motor Finocyl(fin in cylinder) grain using simulated *** proper method for constructing the grain configuration model,ballistic performance and optimizer integration for analysis was *** is a complex grain configuration,requiring thirteen variables to define the *** large number of variables not only complicates the geometrical construction but also optimization *** representation encapsulates all of the geometric entities pertinent to the grain design in a parametric way,allowing manipulation of grain entity(web),performing regression and automating geometrical data *** to avoid local minima and efficient capacity to explore design space makes simulated annealing an attractive choice as *** is demonstrated with a constrained optimization of Finocyl grain geometry for homogeneous,isotropic propellant,uniform regression,and a quasi-steady,bulk mode internal ballistics model that maximizes average thrust for required deviations from neutrality.

关键词： solid rocket motor Finocyl(fin in cylinder) grain internal ballistics simulated annealing computer aided design