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Communications in Theoretical Physics 2018年第1期69卷 43-49页

作者： Sara Parsaei ali akbar Rajabi Faculty of Physics Shahrood University of Technology P.O. Box ***-316 Shahrood Iran Shams Institute of Higher Education Golestan Province Gonbad Iran

The electromagnetic transition between the nucleon and excited baryons has long been recognized as an important source of information for understanding strong interactions in the domain of quark confinement. We study the electromagnetic properties of the excitation of the negative parity the N~*(1535) resonances in the nonrelativistic constituent quark model at large momentum transfers and have performed a calculation the longitudinal and transverse helicity amplitudes. Since the helicity amplitudes depend strongly on the quark wave function in this paper, we consider the baryon as a simple, non-relativistically three-body quark model and also consider a hypercentral potential scheme for the internal baryon structure, which makes three-body forces among three quarks. Since the hyper central potential depends only on the hyper radius, therefore, the Cornell potential which is a combination of the Coulombic-like term plus a linear confining term is considered as the potential for interaction between quarks. In our work, in solving the Schrodinger equation with the Cornell potential, the Nikiforov–Uvarov method employed, and the analytic eigen-energies and eigen-functions obtained. By using the obtained eigen-functions, the transition amplitudes calculated. We show that our results in the range Q^2> 2GeV^2 lead to an overall better agreement with the experimental data in comparison with the other three non-relativistic quark models.

关键词： electroexcitation nonrelativistic constituent quark model the negative parity the N^* (1535) resonances

CFD simulation of gas-solid flow patterns in a downscaled combustor-style FCC regenerator

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Particuology 2018年第4期16卷 96-108页

作者： Abbas Azarnivand Yaghoub Behjat ali akbar Safekordi Department of Chemical and Petroleum Engineering SharifUniversity of Technology Tehran lran Process Development and Equipment Technology Division Research Institute of Petroleum Industry Tehran Iran

To investigate the gas-solid flow pattern of a combustor-style fluid catalytic cracking regenerator, a laboratory-scale regenerator was designed. In scaling down from an actual regenerator, large-diameter hydrodynamic effects were taken into consideration. These considerations are the novelties of the present study. Applying the Eulerian-Eulerian approach, a three-dimensional computational fluid dynamics （CFD） model of the regenerator was developed. Using this model, various aspects of the hydrodynamic behavior that are potentially effective in catalyst regeneration were investigated. The CFD simulation results show that at various sections the gas-solid flow patterns exhibit different behavior because of the asymmetric location of the catalyst inlets and the lift outlets. The ratio of the recirculated catalyst to spent catalyst determines the quality of the spent and recirculated catalyst mixing and distribution because the location and quality of vortices change in the lower part of the combustor. The simulation results show that recirculated catalyst considerably reduces the air bypass that disperses the catalyst particles widely over the cross section. Decreasing the velocity of superficial air produces a complex flow pattern whereas the variation in catalyst mass flux does not alter the flow pattern significantly as the flow is dilute.

关键词： Fluid catalytic cracking Combustor-style regeneratorLarge-diameter fluidized bed Hydrodynamics Gas-solid flow patternRecirculated catalyst

Experimental evaluation and modeling of liquid jet penetration to estimate droplet size in a three-phase riser reactor

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Chinese Journal of Chemical Engineering 2016年第2期24卷 293-309页

作者： ali akbar Jamali Shahrokh Shahhosseini Yaghoub Behjat School of Chemical Engineering Iran University of Science and Technology (IUST) Process Development and Equipment Technology Division Research Institute of Petroleum Industry

In this work, the effects of injecting an evaporating liquid jet into solid-gas flow are experimentally investigated. A new model （SHED model） and a supplementary model （spray model） have also been proposed to investigate some flow-field characteristics in three-phase fluidized bed with the mean relative error 4.3% between model and measured results. Some experiments were conducted to study the influences of flow-field parameters such as liquid volumetric flow rate, injection velocity, jet angle and gas superficial velocity as well as solid mass flux on the jet penetration depth （JPD）. In addition, independent variables were experimentally employed to propose two empirical correlations for JPD by using multiple regression method and spray cone angle （SCA） by using dimensional analysis technique. The mean relative errors between the JPD and SCA correlations versus ex- perimental data were 7.5% and 3.9%, respectively. In addition, in order to identify the variable effect, a parametric study was carried out. Applying the proposed model can avoid direct use of expensive devices to measureJPD and to nredict dronlet size.

关键词： FC-C riser reactor Hydrod ynamics Heterogeneous vaporization Jet penetration depth (JPD) Spray cone angle (SCA)

Effect of fin attachment on thermal stress reduction of exhaust manifold of an off road diesel engine

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Journal of Central South University 2017年第3期24卷 546-559页

作者： ali akbar Partoaa Morteza Abdolzadeh Masoud Rezaeizadeh Department of Mechanical Engineering Graduate University of Advanced Technology Kerman Iran

The effect of fin attachment on the thermal stress reduction of exhaust manifold of an off road diesel engine(Komatsu HD325-6) was *** doing this,coupled thermo-fluid-solid analysis of exhaust manifold of the off road diesel engine was carried *** thermal analysis,including thermal flow,thermal stress,and the thermal deformation of the manifold was *** flow inside the manifold was simulated and then its properties including velocity,pressure,and temperature were *** flow properties were transferred to the solid model and then the thermal stresses and the thermal deformations of the manifold under different operating conditions were ***,based on the predicted thermal stresses and thermal deformations of the manifold body shell,two fin types as well as body shell thickness increase were applied in the critical induced thermal stress area of the manifold to reduce the thermal stress and thermal *** results of the above modifications show that the combined modifications,*** thickness increase and the fin attachment,decrease the thermal stresses by up to 28% and the contribution of the fin attachment in this reduction is much higher compared to the shell thickness increase.

关键词： manifold exhaust simulation modification thermal stress deformation diesel engine

Effect of mass transfer limitations on catalyst performance during reduction and carburization of iron based Fischer-Tropsch synthesis catalysts

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Journal of Energy Chemistry 2013年第5期22卷 795-803页

作者： akbar Zamaniyan Yadollah Mortazavi Abbas ali Khodadadi ali Nakhaei Pour Department of Natural Gas Conversion Gas Research Division Research Institute of Petroleum Industry (RIPI) School of Chemical Engineering University College of Engineering University of Tehran

Existence of intraparticle mass transfer limitations under typical Fischer-Tropsch synthesis has been reported previously,but there is no suitable study on the existence of intraparticle diffusion limitations under pretreatment steps (reduction and activation) and their effect on catalytic performance for iron based *** this study,Fe-Cu-La-SiO2 catalysts were prepared by co-precipitation *** investigate the intraparticle mass transfer limitation under reduction,activation and reaction steps,and its effect on catalytic performance,catalyst pellets with different sizes of 6,3,1 and 0.5 mm have been *** catalysts were calcined,pretreated and tested under similar *** catalysts were activated in hydrogen (5%H2in N2) at 450℃ for 3 h and exposed to syngas (H2/CO=1) at 270℃ and atmospheric pressure for 40 ***,FTS reaction tests were performed for approximately 120 h to reach steady state conditions at 290℃,17 bar and a feed flow (syngas H2/CO=1) rate of 3 L/h (STP).Using small pellets resulted in higher CO conversion,FT reaction rate and C5+ productivity as compared with larger *** small pellets reached steady state conditions just 20 h after starting the *** for larger pellets,CO conversion,FT reaction rate and C5+ productivity increased gradually,and reached steady state and maximum values after 120 h of *** results illustrate that mass transfer limitations exist not only for FTS reaction but also for the reduction and carburization steps which lead to various phase formation through catalyst *** the results indicate that some effects of mass transfer limitations in activation step,can be compensated in the reaction *** results can be used for better design of iron based catalyst to improve the process economy.

关键词： Fischer-Tropsch mass transfer limitation activation catalyst GTL

Extraordinary adsorption of acidic fuchsine and malachite green onto cheap nano-adsorbent derived from eggshell

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Chinese Journal of Chemical Engineering 2020年第6期28卷 1591-1602页

作者： Atefeh Moosavi ali akbar Amooey ali alinejad mir Mojtaba Hedayati Marzbali Faculty of Chemistry University of MazandaranBabolsarIran Department of Chemical Engineering University of MazandaranBabolsarIran Chemical&Environmental Engineering School of EngineeringRMIT UniversityMelbourneVictoria 3000Australia

Removal of dyestuffs such as Acidic Fuchsine(AF)and Malachite Green(MG)being present in many forms in industries is vital to protect water reservoirs from their catastrophic effects on the *** study attempts to effectively eliminate these dyes using a low-cost and eco-friendly ***,as a biocompatible by-product,was initially characterized,then some modifications were conducted,and its morphology and chemical structure were then examined through(Atomic force microscopy)AFM,(Fourier-Transform Infrared Spectroscopy)FTIR,(Energy-Dispersive X-ray Spectroscopy)EDS and(Brunauer–Emmett–Teller)BET *** revealed that the modifications on raw material gave rise to a natural nano-adsorbent presenting porous medium appropriate for targeted adsorbate molecules with the average particle size and average pore diameter of 54 and^2 nm,*** groups on the adsorbent surface were also of importance to assist the adsorption of AF and *** effect of contact time,adsorbent dose,solution p H and initial concentration was ***-second order model accurately correlated the experimental kinetic data for both ***,the participation of intra-particle diffusion along with film diffusion in controlling the process was *** isotherm model fitted very well to the equilibrium data for both dyes and maximum monolayer adsorption capacity of AF and MG was accordingly calculated to be 5000 and 3333.33 mg·g-1 *** inherent characteristics of eggshell make it a potential material to remove contaminants from wastewater in future applications.

关键词： Egg shell Acidic Fuchsine Malachite Green Ultrahigh adsorption

Experimental investigation of typical surface treatment effect on velocity fluctuations in turbulent flow around an airfoil

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Chinese Journal of Aeronautics 2023年第10期36卷 112-123页

作者： Babak ELHAMI Mojtaba DEHGHAN MANSHADI ali akbar DEHGHAN Faculty of Mechanical Engineering Malek Ashtar University of TechnologyIsfahan 177415875Iran Mechanical Engineering Faculty Yazd UniversityYazd ***Iran

Noise reduction of different airfoils is important because these sections are used in wind turbines,propellers,and aircraft *** methods are used for passive noise reduction of *** of these methods is the use of surface *** this research,the effect of the typical surface treatment element(finlets)on the vortex structure at different frequencies in the turbulent flow created on the NACA2412 section is *** this purpose,one-dimensional hot wire probe is *** used surface treatment in this research has a special geometry and the distance between two consecutive finlets is 6 mm(S=6 mm).This study shows that this surface treatment element can be used for noise reduction in high *** result of this research is the suggestion of the most suitable position to install this special surface treatment element to reduce vortex energy in all frequency *** installation location is determined based on a dimensionless parameter(X_(aft)/h).

关键词： Finlet spacing Passive noise reduction Sound Pressure Level(SPL) Surface treatment(finlets) Velocity power spectral density

Modeling of two-phase particulate flows in a confined jet with a focus on two-way coupling

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Particuology 2018年第4期16卷 78-87页

作者： Babak Yousefi-Lafouraki Abas Ramiar ali akbar Ranjbar Faculty of Mechanical Engineering Semnan University lran Faculty of Mechanical Engineering Babol Noshirvani University of Technology Iran

A computational fluid dynamics model is used for the simulation of laminar flow ofwater-Al2O3 nanofluid in a confined slot impinging jet. The （steady-state and two-dimensional） Eulerian-Lagrangian model is used considering fluid-particle and particle-wall interactions （i.e., two-way coupling）. A collocated grid and the SIMPLE algorithm are used for the coupling of pressure and velocity fields. The deposition model is used to investigate the effect of particle deposition on the impingement surface. Results indicate that the particle trajectory becomes stable farther from the jet with a rising Reynolds number and jet- impingement surface distance ratio. The heat transfer coefficient of the mixture model is higher than that of the Eulerian-Lagrangican model.

关键词： Eulerian-Lagrangian approach Two-way coupling Particle tracing Mixture model

Biodegradable starch/poly(vinyl alcohol) film reinforced with titanium dioxide nanoparticles

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International Journal of Minerals,Metallurgy and Materials 2013年第10期20卷 1001-1011页

作者： Zahra Hejri ali akbar Seifkordi ali Ahmadpour Seyed Mojtaba Zebarjad Abdolmajid Maskooki Department of Chemical Engineering Science and Research BranchIslamic Azad University Department of Chemical Engineering Ferdowsi University of Mashhad Department of Materials Science and Engineering Engineering FacultyShiraz University Research Institute of Food Science and Technology

Biodegradable starch/poly （vinyl alcohol）/nano-titanium dioxide （ST/PVA/nano-Ti02） nanocomposite films were prepared via a solution casting method. Their biodegradability, mechanical properties, and thermal properties were also studied in this paper. A general full factorial experimental approach was used to determine effective parameters on the mechanical properties of the prepared films. ST/PVA/TiO2 nanocomposites were characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The results of mechanical analysis show that ST/PVA films with higher contents of PVA have much better mechanical properties. In thermal analysis, it is found that the addition of Ti02 nanoparticles improves the thermal stability of the films. SEM micrographs, taken from the fracture surface of samples, illustrate that the addition of PVA makes the film softer and more flexible. The results of soil burial biodegradation indicate that the biodegradability of ST/PVA/TiO2 films strongly depends on the starch proportion in the film matrix. The degradation rate is increased by the addition of starch in the films.

关键词： nanocomposite films titanium dioxide nanopaxticles biodegradability mechanical properties thermogravi-metric analysis

Assessment of water depth change patterns in 120° sharp bend using numerical model

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Water Science and Engineering 2016年第4期9卷 336-344页

作者： Azadeh Gholami Hossein Bonakdari ali akbar Akhtari Department of Civil Engineering Razi University

In this study,FLUENT software was employed to simulate the flow pattern and water depth changes in a 120° sharp bend at four discharge *** verify the numerical model,a 90° sharp bend was first modeled with a three-dimensional numerical model,and the results were compared with available experimental *** on the numerical model validation,a 120° bend was *** results show that the rate of increase of the water depth at the cross-section located 40 cm before the bend,compared with the cross-sections located 40 cm and 80 cm after the bend,decreases with the increase of the normal water depth in the 120° curved ***,with increasing normal water depth,the dimensionless water depth change decreases at all *** the interior cross-sections of the bend,the transverse water depth slope of the inner half-width is always greater than that of the outer half-width of the ***,the water depth slope is nonlinear at each crosssection in sharp *** equations reflecting the relationships between the maximum and minimum dimensionless water depths and the normal water depth throughout the channel were obtained.

关键词： Water depth change 120sharp bend Experimental model Numerical model Discharge rate Normal water depth FLUENT software