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A laboratory study of hot WAG injection into fractured and conventional sand packs

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Petroleum Science 2009年第4期6卷 400-404页

作者： m J Dorostkar A mohebbi A Sarrafi A Soltani Department of Chemical Engineering College of EngineeringShahid Bahonar University of Kerman

Gas injection is the second largest enhanced oil recovery process, next only to the thermal method used in heavy oil fields. To increase the extent of the reservoir contacted by the injected gas, the gas is generally injected intermittently with water. This mode of injection is called water-alternating-gas (WAG). This study deals with a new immiscible water alternating gas (IWAG) EOR technique, “hot IWAG” which includes combination of thermal, solvent and sweep techniques. In the proposed method CO2 will be superheated above the reservoir temperature and instead of normal temperature water, hot water will be used. Hot CO2 and hot water will be alternatively injected into the sand packs. A laboratory test was conducted on the fractured and conventional sand packs. Slugs of water and CO2 with a low and constant rate were injected into the sand packs alternatively; slug size was 0.05 PV. Recovery from each sand pack was monitored and after that hot water and hot CO2 were injected alternatively under the same conditions and increased oil recovery from each sand pack and breakthrough were measured. Experimental results showed that the injection of hot WAG could significantly recover residual oil after WAG injection in conventional and fractured sand packs.

关键词： Hot water-alternating-gas (WAG) enhanced oil recovery (EOR) fractured sand pack conventional sand pack gas injection

Natural convection of nanofluid over vertical plate embedded in porous medium: prescribed surface heat flux

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Applied mathematics and mechanics(English Edition) 2013年第6期34卷 669-686页

作者： A. NOGHREHABADI A. BEHSERESHT m. GHALAmBAZ Department of mechanical Engineering Shahid Chamran University of Ahvaz

The aim of the present paper is to analyze the natural convection heat and mass transfer of nanofluids over a vertical plate embedded in a saturated Darcy porous medium subjected to surface heat and nanoparticle fluxes. To carry out the numerical solution, two steps are performed. The governing partial differential equations are firstly simplified into a set of highly coupled nonlinear ordinary differential equations by appropriate similarity variables, and then numerically solved by the finite difference method. The obtained similarity solution depends on four non-dimensional parameters, i.e., the Brownian motion parameter （Nb）, the buoyancy ratio （Nr）, the thermophoresis parameter （Nt）, and the Lewis number （Le）. The variations of the reduced Nusselt number and the reduced Sherwood number with Nb and Nt for various values of Le and Nr are discussed in detail. Simulation results depict that the increase in Nb, Nt, or Nr decreases the reduced Nusselt number. An increase in the Lewis number increases both of the reduced Nusselt number and the Sherwood number. The results also reveal that the nanoparticle concentration boundary layer thickness is much thinner than those of the thermal and hydrodynamic boundary layers.

关键词： natural convection porous medium nanofluid surface heat flux surfacenanoparticle flux

Application of a finite element method to stress distribution in buried patch repaired polyethylene gas pipes

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Underground Space 2019年第1期4卷 48-58页

作者： R.Khademi-Zahedi m.Shishesaz shahid Chamran University of Ahvaz AhvazIran

Advantages of polyethylene pipes over traditional steel or metal pipes have increased industry interest in the use of polyethylene(PE)pipelines for underground applications and especially in gas distribution *** this study,finite element analysis is used to calculate the stress distribution in a patch repaired defective gas pipe under internal *** pipe is assumed to be buried at a depth of 125 *** material is assumed to be medium density PE80B,where the patch material was selected from high density polyethylene(HDPE).During the loading process,the seasonal pipe temperature changes,surcharge loads,soil column weight,and soil-pipe interaction were included in the *** types of patch arrangements were selected to repair the damaged *** shape of the defect hole was deemed as circular or *** respect to elliptic defects,various minor to major diameter ratios,a/b,were selected to simulate a circular to a crack shaped *** on the results,the semi-circular and saddle fusion patches decrease the peak von mises stress in the pipe by almost the same ***,the minimum peak von mises stress in the patch corresponds to the saddle fusion repair *** on the results,with respect to a saddle fusion repair,when the shape of the defect approaches a crack,the peak von mises stress in the pipe almost doubles and exceeds the pipe allowable stress for a working life of 50 *** respect to higher values of a/b,the stress level in the patch repaired pipe is significantly below its limiting value for the same life expectancy.

关键词： Patch repair Buried gas pipe mDPE HDPE Temperature variation

Fabrication of an r-Al_2Ti intermetallic matrix composite reinforced with α-Al_2O_3 ceramic by discontinuous mechanical milling for thermite reaction

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International Journal of minerals,metallurgy and materials 2014年第10期21卷 1037-1043页

作者： A.mosleh m.Ehteshamzadeh R.Taherzadeh mousavian Department of materials Science and Engineering Shahid Bahonar University of Kerman Department of metallurgy Zanjan Branch Islamic Azad University

In this study, a powder mixture with an Al/TiO2 molar ratio of 10/3 was used to form an r-Al2Ti intermetallic matrix composite （ImC） reinforced with α-Al2O3 ceramic by a novel milling technique, called discontinuous mechanical milling （Dmm） instead of milling and ignition of the produced thermite. The results of energy dispersive X-ray spectroscopy （EDX） and X-ray diffraction （XRD） of samples with varying milling time indicate that this fabrication process requires considerable mechanical energy. It is shown that Al2Ti-α-Al2O3 ImC with small grain size was produced by Dmm after 15 h of ball milling. Peaks for γ-TLA1 as well as Al2Ti and Al2O3 are observed in XRD patterns after Dmm followed by heat treatment. The microhardness of the Dmm-treated composite produced after heat treatment was higher than Hv 700.

关键词： composite materials intermetallics alumina titanium aluminide ball milling thermite reaction process

Assessment of pH-responsive nanoparticles performance on laboratory column flotation cell applying a real ore feed

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International Journal of mining Science and Technology 2020年第2期30卷 197-205页

作者： Samiramis Nasirimoghaddam Ali mohebbi mohsen Karimi m.Reza Yarahmadi Department of Chemical Engineering Faculty of EngineeringShahid Bahonar University of KermanKermanIran Department of Chemistry and Chemical Engineering Chalmers University of TechnologySE-41296 GothenburgSweden Sarcheshmeh Copper Complex KermanIran

Nanoparticles(NPs)can promote the column flotation process in mining ***'effects on column flotation process(copper recovery,grade and flotation rate constant)are assessed in Sarcheshmeh Copper Complex,Iran,through response surface methodology(RSm)optimization *** c-Al2O3,a-Fe2O3,SiO2,and TiO2 nanoparticles are selected for these experiments.A flotation rate constant is chosen as a response to assess the effect of nanoparticles on flotation in its kinetic *** process p H and nanoparticle dosage are selected as the influential *** obtained from RSm indicated that the maximum percentage of Cu recovery and grade is obtained at p H of 12 and nanoparticle dosage of 6 kg/t,through a-Fe2O3 and c-Al2O3 nanoparticles,*** nanoparticles in particular c-Al2O3 and a-Fe2O3 increases the Cu recovery by 8–10%together with the grade by 3–6%in a significant *** is revealed that nanoparticles could effectively be applied in enhancing the flotation performance.

关键词： Column flotation Nanoparticles Cu recovery Response surface methodology

Kinematic analysis of flexible bipedal robotic systems

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Applied mathematics and mechanics(English Edition) 2024年第5期45卷 795-818页

作者： R.FAZEL A.m.SHAFEI S.R.NEKOO Department of mechanical Engineering Shahid Bahonar University of KermanKerman ***Iran Departamento de Ingenieria de Sistemas y Automatica Escuela Técnica Superior de IngenieriaUniversidad de SevillaSeville 41092Spain

In spite of its intrinsic complexities,the passive gait of bipedal robots on a sloping ramp is a subject of interest for numerous *** distinguishes the present research from similar works is the consideration of flexibility in the constituent links of this type of robotic *** is not a far-fetched assumption because in the transient(impact)phase,due to the impulsive forces which are applied to the system,the likelihood of exciting the vibration modes increases ***,the human leg bones that are involved in walking are supported by viscoelastic muscles and ***,for achieving more exact results,it is essential to model the robot links with viscoelastic *** this end,the Gibbs-Appell formulation and Newton's kinematic impact law are used to derive the most general form of the system's dynamic equations in the swing and transient phases of *** most important issue in the passive walking motion of bipedal robots is the determination of the initial robot configuration with which the system could accomplish a periodic and stable gait solely under the effect of gravitational *** extremely unstable nature of the system studied in this paper and the vibrations caused by the impulsive forces induced by the impact of robot feet with the inclined surface are some of the very serious challenges encountered for achieving the above-mentioned *** overcome such challenges,an innovative method that uses a combination of the linearized equations of motion in the swing phase and the algebraic motion equations in the transition phase is presented in this paper to obtain an eigenvalue *** solving this problem,the suitable initial conditions that are necessary for the passive gait of this bipedal robot on a sloping surface are *** effects of the characteristic parameters of elastic links including the modulus of elasticity and the Kelvin-Voigt coefficient on the walking stability of this type of

关键词： bipedal robot flexible link swing phase transient phase eigenvalue problem Kelvin-Voigt coefficient

Superhydrophobic surface of mg alloys:A review

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Journal of magnesium and Alloys 2018年第1期6卷 59-70页

作者： m.Yeganeh N.mohammadi Department of materials Science and Engineering Faculty of EngineeringShahid Chamran University of AhvazAhvazIran

In the present review,the formation of superhydrophobic(SHP)structures on the surface of mg alloys was *** methods including hydrothermal technique,chemical and electrochemical deposition,conversion and polymer coating,and etching routes were *** superhydrophobicity could form on the surface of mg alloys by the application of different chemical,electrochemical,and physical methods followed by the immersion of these alloys in the solution containing modifying agents including fatty acids or long-chain *** formed morphology,composition,and contact angle were reported and the effect of synthesis route on these characteristics was reviewed.

关键词： mg alloys Superhydrophobic surfaces Chemical deposition Electrochemical coating Conversion coating Polymer coating Etching

Kinematic Analysis and Design of a 3-DOF Translational Parallel Robot

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International Journal of Automation and computing 2017年第4期14卷 432-441页

作者： mahmood mazare mostafa Taghizadeh m. Rasool Najafi School of mechanical Engineering Shahid Beheshti University Tehran lran Department of Engineering University of Qom Qom Iran

Parallel mechanisms are widely used in various fields of engineering and industrial applications such as machine tools, flight simulators, earthquake simulators, medical equipment, etc. Parallel mechanisms are restricted to some limitations such as irregular workspace, existence of singular points and complexity of control systems which should be studied and analyzed for effective and efficient use. In this research, a new machine tool with parallel mechanism which has three translational degrees of freedom is studied and the workspace and singular points are determined by deriving analytical equations and then utilizing of matlab software. To do so, forward and inverse kinematics of the mechanism are obtained and workspace and singular points are calculated using a search algorithm. Afterward in order to validate the results, the proposed mechanism is simulated in automatic dynamics analysis of mechanical systems （ADAmS） software. moreover, in order to investigate the quality of robot performance and dexterity of the mechanism in its workspace, global dexterity index （GDI） of the robot is calculated using Jacobean matrix at different positions of the mobile platform.

关键词： Kinematic analysis parallel robot workspace manipulability dexterity.

Retractable Compact Directed Complete Poset （Acts）

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Algebra Colloquium 2017年第4期24卷 625-638页

作者： m. mehdl Ebrahiml mojgan mahmoudi mahdieh Yavari Department of mathematics Shahid Bebeshti University G.C. Tehran 19839 lran

Taking domains in the one hand and actions of a semigroup （automaton） on the other, as two crucial notions in mathematics as well as in computer science, we consider the notion of compact directed complete poset （acts）, and investigate the interesting notion of absolute retractness for such ordered structures. As monomorphisms and embeddings for domain acts are different notions, we study absolute retractness with respect to both the class of monomorphisms and that of embed- dings for compact directed complete poset （acts）. We characterize the absolutely retract compact dcpos as complete compact chains. Also, we give some examples of compact di- rected complete poset acts which are （g-）absolutely retract （with respect to embeddings） and show that completeness is not a sufficient condition for （g-）absolute retractness.

关键词： action of a monoid directed complete poset compact absolutely retract