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Journal of Bionic Engineering 2017年第1期14卷 88-98页

作者： ali akbar Hosseinjani ali Ashrafizadeh Faculty of mechanical Engineering K. N. Toosi University of Technology Tehran P.O.B. 19395-1999 Iran

The flow patterns and wake structures behind a pitching airfoil in an un-bounded domain have been studied extensively. In contrast, the flow phenomena associated with a pitching airfoil near a solid boundary have not been adequately studied or reported. This paper aims at filling this research gap by considering the flow confinement effects on the flow pattern around a pitching airfoil. To achieve this goal, the flow fields around a flapping airfoil in un-bounded, bounded and semi-bounded domains are studied and compared. Numerical simulations are carried out at a fixed Reynolds number, Re = 255, and at a fixed oscillation frequency corresponding to St = 0.22. An accurate immersed boundary method is employed to calculate the unsteady flow fields around the airfoil at various flapping amplitudes. It is argued that two flow mechanisms, here called ＂the interaction effect＂ and ＂the induced reverse flow effect＂ are responsible for the variations of the flow field due to the presence of a nearby solid boundary.

关键词： immersed boundary method pitching airfoil vortex street induced momentum aligned vortex

An extended iterative direct-forcing immersed boundary method in thermo-fluid problems with Dirichlet or Neumann boundary conditions

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Journal of Central South University 2017年第1期24卷 137-154页

作者： ali akbar Hosseinjani ali Ashrafizadeh Faculty of mechanical Engineering K.N.Toosi University of TechnologyP.O.B.19395-1999 TehranIran

An iterative direct-forcing immersed boundary method is extended and used to solve convection heat transfer *** pressure,momentum source,and heat source at immersed boundary points are calculated simultaneously to achieve the best *** of convection heat transfer problems with both Dirichlet and Neumann boundary conditions are *** approaches for the implementation of Neumann boundary condition,*** and indirect methods,are introduced and compared in terms of accuracy and computational *** test cases include forced convection on a heated cylinder in an unbounded flow field and mixed convection around a circular body in a lid-driven ***,the proposed method is applied to study the mixed convection around a heated rotating cylinder in a square enclosure with both iso-heat flux and iso-thermal boundary *** results show that the order of accuracy of the indirect method is less than the direct ***,the indirect method takes less computational time both in terms of the implementation of the boundary condition and the post processing time required to compute the heat transfer variables such as the Nusselt *** is concluded that the iterative direct-forcing immersed boundary method is a powerful technique for the solution of convection heat transfer problems with stationary/moving boundaries and various boundary conditions.

关键词： Dirichlet 诺伊曼边界条件边界法浸入迭代流体问题对流换热计算效率

An Analysis on Failure Reasons of Quit Smoking among Smokers in Beijing Communities——Based on a Cross-Sectional Study

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Biomedical and Environmental Sciences 2022年第1期35卷 84-88页

作者： JIN Qian Ying LI Xing ming LIU Han mA Han Qiao QIAO Kun ali akbar School of Public Health Capital Medical UniversityBeijing 100069China

With the implementation of tobacco control policies and increasing publicity year by year,smokers have acquired more information and knowledge through various channels about the harmful effects of *** a result,more sm... 详细信息

关键词： smoke desire harmful

Experimental investigation of the effects of shrub filter strips on debris flow trapping and interception

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International Journal of Sediment Research 2023年第2期38卷 265-278页

作者： Songtang He Wenle Chen Daojie Wang Xiaoqing Chen Yuchao Qi Peng Zhao Yong Li Yongming Lin ali akbar Jamali Key Laboratory of mountain Hazards and Earth Surface Processes Chinese Academy of Sciences Institute of mountain Hazards and Environment Chinese Academy of Sciences University of Chinese Academy of Sciences Pipe China Southwest Pipeline Company Key Laboratory for Forest Ecosystem Process and management College of Forestry Fujian Agriculture and Forestry University Department of GIS-RS and Watershed management Maybod Branch Islamic Azad University

Ecological engineering plays an increasingly significant role in mountain hazard control, but the effect of species selection and arrangement(e.g., row spacing and stem spacing) on debris flow suppression is still unclear. To further understand the interception efficiency of shrub arrangement parameters on debris flow and explore the difference with slow hydraulic erosion, sixteen sets of small-scale flume experiments with different stem and row spacings were done to study the effects of shrubs on debris flow severity, flow rate, velocity, and particle size. The results suggest that, for a dilute debris flow, sediment interception effectiveness(27.4%-60.9%) decreases gradually as stem spacing increases. moreover, as row spacing increases, flow velocity reduction(34.4%-44.9%) and flow reduction(18.5%-47.4%) gradually decrease; and the bulk density reduction(0.5%-5.3%) and sediment interception increase initially and then decrease. In contrast, for a viscous debris flow, the flow reduction, flow velocity reduction, and sedimentation interception decrease gradually as the stem spacing increases. As row spacing increases,the flow velocity reduction, flow reduction, and sediment interception all increase initially and then decrease. A formula for the flow velocity of dilute debris flow after the filter strip was derived based on the energy conservation law and Bernoulli’s equation, confirming that debris flow movement is closely related to the degree of vegetation cover. This research strengthens the current understanding of the effectiveness of vegetation in debris flow disaster prevention and control and can guide practical applications.

关键词： Ecological engineering mountain hazards mitigation and prevention Shrub filter strips Debris flow Sediment trapping

An algorithm for the anchor points of the PPS of the BCC model

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Financial Innovation 2022年第1期8卷 2368-2381页

作者： Dariush akbarian ali akbar Bani mohsen Rostamy-malkhalifeh Farhad Hosseinzadeh Lotfi Department of mathematics Arak BranchIslamic Azad UniversityArakIran Department of mathematics Gorgan BranchIslamic Azad UniversityGorganIran Department of mathematics Science and Research BranchIslamic Azad UniversityTehranIran

Anchor points play an important role in data envelopment analysis theory and applications;they delineate the efficient part of the production possibility set(PPS)*** this paper,we propose an approach for finding the anchor points of the PPS of the Banker,Charnes and Cooper(BCC)*** approach is based on a variant of super-efficiency models and their *** necessary and sufficient conditions for the characterization of the anchor points are also ***,the applicability of the proposed model is illustrated with some numerical examples.

关键词： Data envelopment analysis(DEA) Anchor point Production Possibility Set(PPS) Efficient and inefficient boundary

Relativistic symmetries in the Hulthn scalar-vector-tensor interactions

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Chinese Physics B 2013年第8期22卷 257-263页

作者： majid Hamzavi ali akbar Rajabi Department of Science and Engineering Abhar Branch Islamic Azad UniversityAbhar Iran Physics Department Shahrood University of TechnologyShahrood Iran

In the presence of spin and pseudospin （p-spin） symmetries, the approximate analytical bound states of the Dirac equation for scalar-vector-tensor Hulth6n potentials are obtained with any arbitrary spin-orbit coupling number using the Pekeris approximation. The Hulth6n tensor interaction is studied instead of the commonly used Coulomb or linear terms. The generalized parametric Nikiforov-Uvarov （NU） method is used to obtain energy eigenvalues and corresponding wave functions in their closed forms. It is shown that tensor interaction removes degeneracy between spin and p-spin doublets. Some numerical results are also given.

关键词： Dirac equation Hulth6n scalar-vector-tensor potential spin and p-spin symmetry NU method

GIS based ArcPRZm-3 model for bentazon leaching towards groundwater

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Journal of Environmental Sciences 2010年第12期22卷 1854-1859页

作者： Tahir ali akbar Henry Lin College of Natural Resources University of Wisconsin-Stevens Point Department of Civil Engineering Schulich School of EngineeringUniversity of Calgary2500 University Drive NWCalgaryAlbertaT2N 1N4Canada Department of Crop and Soil Sciences The Pennsylvania State UniversityUniversity ParkPA 16802USA

Groundwater contamination due to pesticide applications on agricultural lands is of great environmental concern. The mathematical models help to understand the mechanism of pesticide leaching in soils towards groundwater. We developed a user-friendly model called ArcPRZm-3 by integrating widely used Pesticide Root Zone model version 3 （PRZm-3） using Visual Basic and Geographic Information System （GIS） based Avenue programming. ArcPRZm-3 could be used to simulate pesticide leaching towards groundwater with user-friendly input interfaces coupled with databases of crops, soils and pesticides. The outputs from ArcPRZm-3 could be visualized in user-friendly formats of tables, charts and maps. In this study we evaluated ArcPRZm-3 model by simulating bentazon leaching in soil towards groundwater. ArcPRZm-3 was applied to 37 sites in Woodruff County, Arkansas, USA to observe the daily average dissolved bentazon concentration for soybean, sorghum and rice at a depth of 1.8 m for a period of two years. Nineteen ranks of bentazon leaching potential were obtained using ArcPRZm-3 for all sites having different soil and crop combinations. ArcPRZm-3 simulation results for bentazon were compatible with the field monitored data in term of relative ranking and trend, although some uncertainties exist. This study indicated that macropore flow mechanism would be important in analyzing the effect of irrigation on groundwater contamination due to pesticides. Overall, ArcPRZm-3 could be used to simulate pesticide leaching towards groundwater more efficiently and effectively as compared to PRZm-3.

关键词： ArcPRZm-3 PRZm-3 GIS pesticide leaching groundwater contamination bentazon

EFFECT OF POLYANILINE AS A SURFACE mODIFIER OF TiO_2 NANO-PARTICLES ON THE PROPERTIES OF POLYVINYL CHLORIDE/TiO_2 NANOCOmPOSITES

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Chinese Journal of Polymer Science 2013年第3期31卷 481-494页

作者： ali Olad Sepideh Behboudi ali akbar Entezami Polymer Composite Research Laboratory Department of Applied ChemistryFaculty of ChemistryUniversity of Tabriz Polymer Research Laboratory Department of Organic ChemistryFaculty of ChemistryUniversity of Tabriz

Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles （PANI-TiO2） were characterized with the FT-IR, XRD, SEm and TEm techniques. Results confirmed that PANI was grafted successfully on the surface of TiO2 nanoparticles, therefore agglomeration of nanoparticles decreased dramatically. Polyvinyl chloride nanocomposites filled with 1 wt%-5 wt% of PANI-TiO2 and TiO2 nanoparticles were prepared via the solution blending method. PVC nanocomposites were analyzed with FT-IR, XRD, SEm, TG/DTA, DSC and tensile test techniques. Effect of PANI as surface modifier of nanoparticles was discussed according to the final properties of PVC nanocomposites. Results demonstrated that deposition of PANI on the surface of TiO2 nanoparticles improved the interfacial adhesion between the constituents of nanocomposites, which resulted in better dispersion of nanoparticles in the PVC matrix. Also PVC/PANI-TiO2 nanocomposites showed higher thennal resistance, tensile strength and Young＇s modulus compared to those of unfilled PVC and PVC/TiO2 nanocomposites.

关键词： Polymer nanocomposite Polyvinyl chloride Polyaniline TiO2 nano-additive Surface modification.

Bright, periodic, compacton and bell-shape soliton solutions of the extended QZK and (3+1)-dimensional ZK equations

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Communications in Theoretical Physics 2021年第10期73卷 23-35页

作者： m.ali akbar md Abdul Kayum m S Osman Department of Applied mathematics University of RajshahiBangladesh Department of Computer Science&Engineering North Bengal International UniversityRajshahiBangladesh Department of mathematics Faculty of ScienceCairo UniversityGiza 12613Egypt

The(3+1)-dimensional Zakharov–Kuznetsov(ZK) and the new extended quantum ZK equations are functional to decipher the dense quantum plasma, ion-acoustic waves, electron thermal energy,ion plasma, quantum acoustic waves, and quantum Langmuir waves. The enhanced modified simple equation(EmSE) method is a substantial approach to determine competent solutions and in this article, we have constructed standard, illustrative, rich structured and further comprehensive soliton solutions via this method. The solutions are ascertained as the integration of exponential, hyperbolic,trigonometric and rational functions and formulate the bright solitons, periodic, compacton, bellshape, parabolic shape, singular periodic, plane shape and some new type of solitons. It is worth noting that the wave profile varies as the physical and subsidiary parameters change. The standard and advanced soliton solutions may be useful to assist in describing the physical phenomena previously mentioned. To open out the inward structure of the tangible incidents, we have portrayed the three-dimensional, contour plot, and two-dimensional graphs for different parametric values. The attained results demonstrate the EmSE technique for extracting soliton solutions to nonlinear evolution equations is efficient, compatible and reliable in nonlinear science and engineering.

关键词： (3+1)-dimensional ZK the extended QZK equation enhanced modified simple equation method soliton solutions NLEEs

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