توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Multi–objective Optimal Placement of Structural Control Actuators
نویسنده(ها): ،
اطلاعات انتشار: هفتمین همایش انجمن هوافضای ایران، سال
تعداد صفحات: ۸
This paper presents a multi–objective optimization method for optimal placement of actuators used to control the vibration of seismically excited structures. In the proposed optimization procedure, a genetic algorithm is employed to minimize a suitably defined objective index, taking into account the human and structural survivability as well as the amount of control force applied by the actuators. As a case study, the optimal assignment of seismic vibration control actuators of a well–known 20–story benchmark building is performed using the proposed approach. It is shown in the paper that a better control performance, compared to the works of other researchers, can be achieved when actuators are located at optimal places.<\div>

۲Model–Based Fuzzy Control of an Auto Swing–up Furuta Inverted Pendulum: A Mechatronic Approach
نویسنده(ها): ، ، ،
اطلاعات انتشار: دومین کنفرانس بین المللی و هشتمین کنفرانس ملی مهندسی ساخت و تولید، سال
تعداد صفحات: ۱۰
In this paper, a report on the IUST Furuta Inverted Pendulum, designed and built at the Mechanical Engineering Department of the Iran University of Science and Technology (IUST), is provided. This work is carried out by a group of students, as part of the Mechatronics graduate course. A new fuzzy controller based on the idea of energy control is proposed, to swing up the inverted pendulum to the upright position. Furthermore, a model–based parallel distributed compensation (PDC) scheme is employed to stabilize the pendulum at its unstable equilibrium point, while the position of the arm is also controlled. Experimental results show the outstanding stability, performance and robustness of the controlled system.<\div>

۳The effect of the Microstructure and Chemical Compositions on the Glass Dies life
نویسنده(ها): ، ،
اطلاعات انتشار: دهمین کنفرانس ملی مهندسی ساخت و تولید، سال
تعداد صفحات: ۱۴
Cast irons are commonly used as mold material in the production of glass materials. Since growth and scaling are the main failure mechanisms that limit the surface life of glass molds, the aim of the present study was to examine the growth and scaling behavior of cast irons by the addition of alloying elements. Glass mold cast irons must exhibit both heat resistance and oxidation resistance and this dual requirement can be met by A and spheroidal types graphite structures and small amount of Mo, Ni, Sn, Cr, Mn and Cu alloying. It is found that the gray cast irons consist of Mo٫ Mn and Cr alloying elements have high relative oxidation resistance about 4٪ with respect to Sn alloyed gray cast iron. The change of graphite morphology (lamellar to spheroidal shape) increased about 7٪ with respect to alloyed gray cast iron.<\div>

۴Analytical and finite element solutions for bending of functionally graded piezoelectric beams
نویسنده(ها): ، ، ،
اطلاعات انتشار: هفدهمین کنفرانس سالانه مهندسی مکانیک، سال
تعداد صفحات: ۶
This paper makes attempt to investigate bending of functionally graded piezoelectric beams based on the euler –bernoulli beam theory under mechanical load.<\div>

۵Coupled Thermoelasticity of Functionally Graded Plates Based on First–Order Shear Deformation Theory
نویسنده(ها): ، ، ،
اطلاعات انتشار: هجدهمین کنفرانس سالانه مهندسی مکانیک، سال
تعداد صفحات: ۱۰
In this study, an analytical solution is presented for a plate based on the first–order shear deformation theory with functionally graded materials (FGM) subjected to lateral thermal shock loads. Material properties of the plate, except Poisson’s ratio, are assumed to be graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. The solution is obtained under classical coupled thermoelastic assumption. A third–order polynomial temperature profile has been considered across the plate thickness with unknown constants. By substituting the profile into equations of motion and energy equation and applying Galerkin method we acquire nine equations for analyzing coupled thermoelasticity of the FGM plate which must be solved simultaneously. The governing partial differential equations are solved using Fourier series expansion method. Using the Laplace transform, the unknown variables are obtained in the Laplace domain. Applying the analytical Laplace inversion method, the solution in time domain is derived. The analytical approach supports us to be able to submit a mathematical expression for classical coupled thermoelastity of the FGM plate. Computed results for the plate with simply supported boundary conditions are presented for different power law indices and various aspect ratios of the plate. Results show that the plate under coupledthermoelasticity assumption vibrates around the steady state situation and vibration amplitude decreases intensively with passing the time. Although, coupled thermoelasticity assumption affects both of temperature and deflection responses, the coupling effect is more apparent in the lateral deflection of the plate. Furthermore validating the process is accomplished by verifying thermomechanical responses and natural frequencies of the FGM plate based on the FSDT with known data reported in the literature.<\div>

۶Experimental study on fracture behavior of rubber–toughened epoxy in bulk and laminated composite specimens
نویسنده(ها): ، ،
اطلاعات انتشار: دومین کنفرانس بین المللی کامپوزیت، سال
تعداد صفحات: ۶
To study the toughening mechanisms of liquid rubber (LR) in bulk epoxy and laminated composite, experimental investigations were carried out on single–edge notched bending (SENB), double–cantilever–beam (DCB) and end notch flexure (ENF) specimens under mode–I and II loading. The matrix materials were pure epoxy (bisphenol A) and LR (ATBN, CTBN, VTBN) modified epoxies. The results showed that using rubber particles would improve fracture toughness of neat epoxy resin and laminated composites. The behavior of the composite was affected by the pattern that the particles are spread in resin or the final laminated composite. Inappropriate spread of the particles would decrease the fracture toughness in some cases. However, if they are spreaded perfectly, they will improve the composite resistance against fracture. The modulus, E, of the epoxy polymer decreases with the addition of the LR. Of course, these relatively minor changes in these properties of the rubber–toughened epoxy polymer are more than compensated for by the significant increases in the fracture toghness value. The poor toughness behavior of CTBN in the glass fiber laminate was thought to be caused by the concentration of LR particles in the resin–fiber bonding surface. Morphographs of the fracture surfaces also testified this prospect.<\div>

۷determining optimum values of laser welding parameters for a TWB–using taguchi method
نویسنده(ها): ، ، ،
اطلاعات انتشار: کنگره بین المللی جوش و روشهای اتصال، سال
تعداد صفحات: ۸
in recent years the use of tailor welded blanks TWBs has increased in practice not only in the automotive industry but also in other manufacturing industries TWBs are composed of two or more welded metal sheets with different thicknesses and\or coatings and\or even materials in spite of various benefits of application of TWBs there are some limitations in production and using of them one is the occurrence of fracture in weld or HAZ zones during forming and consequently a dectrase intheir formability so determining proper condition of welding these blanks is too important is this research optimum values of CO2–laser welding parameters for a TWB composed OF IF steel sheets with thicknesses about 0.8 and 1.2 mm in order to get the best formability were determined ormability was investigated by dome height test and erichson test.<\div>

۸Lateral and Torsional Acceleration Spectrum of Iranin Earthquakes Considering the Kinematic Soil–Structure Interaction Effects
نویسنده(ها): ، ، ،
اطلاعات انتشار: چهارمین کنفرانس بین المللی مقاوم سازی، سال
تعداد صفحات: ۱۲
In the traditional dynamic structural analyses, free field responses of the site being used as the foundation input motion. To consider the effects of earthquake torsional motion, an accidental eccentricity is assumed at the imposition point of earthquake forces. However, studies on kinematic soil–structure interaction show that assuming a fixed value for eccentricity by ignoring the geometry and mechanical characteristics such as foundation dimension, soil shear wave velocity, angle of incident wave and the natural frequency of structure significantly reduces the accuracy of results. In this paper an efficient approximation formula is implemented for the estimation of foundation input motion. The lateral and torsional acceleration response spectrum of Iranian earthquakes are evaluated and, changes in the response spectrum with respect to the changes in the ratio of the foundation dimension to the shear wave velocity is also investigated. At the end of the paper the obtained lateral and torsional response spectral for each type of soil are used to estimate the required accidental eccentricities for common structural analysis.<\div>

۹Enhancement of Heat Duty in Heat Exchangers Using Nanofluids
نویسنده(ها): ، ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۱۲
A nanofluid is a suspension of ultrafine particles in a conventional base fluid which tremendously enhances the heat transfer characteristics of the original fluid. In this paper, application of nanofluids for enhancement of heat transfer in an industrial scale heat exchanger (for condensing saturated vapor to subcool water) hasbeen studied. Nanoparticles such as Fe, Cu, Ag, Al, Al2O3, Cuo, Si and SiC with 10 nm diameter added tocooling water or ethylene glycol as cold stream in heat exchanger. Nanoparticles concentration increases from 0.05% – 3% volume percent in cooling water. The heat exchanger is simulated by Aspen Plus softwareand results show that for all nanoparticles, by increasing volume percent of nanoparticles, heat duty of heatexchanger increases up to 9.9%. In addition, results illustrate that the best improvement of duty, when wateracts as the cold stream, is for Ag with 3% volume fraction while this improvement is for SiC with 3% volume fraction when ethylene glycol is as cold stream. Also, the worst case for water occurs for Si and Alwith 0.05% volume percent whereas Ag is considered as the least improvement for ethylene glycol.Moreover, results indicate that the performance of water as fluid base of cold stream excel from ethylene glycol because water physical properties such as thermal conductivity, specific heat and viscosity are more suitable in comparison with ethylene glycol for heat transfer. However, enhancement of heat duty due to nanoparticle addition for ethylene glycol is far better than water.<\div>

۱۰Mathematical Modeling of CO2 Separation Process by Mixed– Matrix Membrane in hollow fiber module membrane as a new separation technology in the gas sweetening plant
نویسنده(ها): ، ،
اطلاعات انتشار: دومین همایش ملی تکنولوژی های نوین در شیمی و پتروشیمی، سال
تعداد صفحات: ۱۰
Membrane separation technology has been widely applied to various chemical and petrochemical industries and it known as a new technology in the separation process . One of the major applications of membrane technology is natural gas processing. In this study, mixed–matrix membrane is chosen as a membrane for separation of CO2 in CO2\CH4 mixture. The membrane is modeled based on the unsteady state and differential conditions with different effective permeability correlations. It is found that the can<\div>

۱۱SIMULATION OF DIFFERENT MECHANISMS DURING CO2 INJECTION IN HAFTKEL FIELD
نویسنده(ها): ، ،
اطلاعات انتشار: سومین کنفرانس بین المللی نفت، گاز و پتروشیمی، سال
تعداد صفحات: ۸
Reservoir management to enhance oil recovery, is always one of the concerns for the countries that have oil resources and each year vast sum of money is spent for research to enhance oil recovery. Owners of oil reserves try to get higher productivity from their own resources with new methods and less expensive methods. One of the most common methods of enhance oil recovery, is displacement of oil with gas injection. Injection of miscible gas is used to reduce or eliminate surface tension forces. On the other hand, most reservoirs of the Middle East region and also Iran are fractured reservoirs. Due to the matrix and fracture system which has different reservoir characteristics, fractured reservoirs are far more complex than conventional reservoir in prediction and simulation of fluid flow. Since typically the maximum amount of oil exists within the matrix, so we should use methods that can displace oil in the matrixes. One of the main methods for enhance oil recovery from fractured reservoirs is using gravity drainage mechanism within the matrix. In this case, injection of carbon dioxide as a miscible gas, is very effective as the low–pressure miscibility and providing a mechanism of gravity drainage and a significant increase in the ultimate recovery factor of this type of reservoirs.In this project, we try to use the information of one of Iranian's oil fields and then, by using the compositional model, the phenomenon of molecular diffusion effect on gravity drainage mechanism will be investigated. The results of the simulation shows, the importance of the phenomenon of molecular diffusion in the non–equilibrium gas injection into fractured reservoirs.<\div>

۱۲Additions to the knowledge of smut fungi (Ustilaginomycetes) of Iran
نویسنده(ها): ، ،
اطلاعات انتشار: رستنيها، سال
تعداد صفحات: ۹
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