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Main System Investigation of Turbocharged Diesel Engine During Performance Upgrade
, M.Sc. Thesis Sharif University of Technology ; Hajilouy Benisi, Ali (Supervisor) ; Nouri Broujerdi, Ali (Supervisor)
Abstract
The internal combustion engine power is determined by the amount of fuel effectively burned inside the engine cylinders. On the other hand, the fuel consumption is proportional to the air mass that enters the cylinders in each cycle. Conventionally, incoming the engine inlet air is at ambient conditions. However, with higher air density, the engine power increases for the same dimensions, so-called turbocharging. Although the engine's structure remains unchanged, it may be necessary to adjust the main systems of the engine simultaneously. This research investigated maximizing the power of a turbocharged diesel engine based on upgrading the degree of turbocharging. For this purpose, the EM355...
Experimental and Modeling Study of Gas/WAG Injection at Near Miscible Condition in One of Iranian Oil Reservoirs
,
M.Sc. Thesis
Sharif University of Technology
;
Ghazanfari, Mohammad Hossein
(Supervisor)
;
Massihi, Mohsen
(Supervisor)
Abstract
Most of the Iranian oil reservoirs are reaching end of their natural production life, hence they are suitable candidates for EOR common processes like gas injection and WAG injection. Studies have shown that gas and WAG injection can be applied for optimal oil production. Past studies have been mainly on gas and WAG injection in immiscible or fully miscible conditions and there is a limited amount of data available on performance of these methods in near miscible conditions. Miscible injection is not feasible in old Iranian oil reservoirs due to their depleted pressure. Moreover injection in lower pressures is attractive from both economical and operational standpoints since this reduces the...
A supervisory fuzzy-PID controller for a MIMO biped robot balance in frontal plane
, Article 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008, Boston, MA, 31 October 2008 through 6 November 2008 ; Volume 2 , 2009 , Pages 307-314 ; 9780791848630 (ISBN) ; Haghshenas Jaryani, M ; Farahmand, F ; Sharif University of Technology
2009
Abstract
In this paper we propose to control a bipedal robot in an unstable position by means of a PID controller that gains are turned by a fuzzy logic system. For that, a model of planar 3 linked segment consisting of limb, trunk and extended arms with fixed base is used. Fuzzy if-then rules are constructed based on human expert knowledge and biomechanics studies for tuning of PID's gain. For construction of tuning rules, we have developed an optical measuring system to record experimental data of balance keeping of a human in an unstable position. The control model is based on three sets of different global variables: (1) limb orientation and its derivative, (2) trunk/upper attitude and its...
Prediction of water content of sour and acid gases
, Article Fluid Phase Equilibria ; Volume 299, Issue 2 , December , 2010 , Pages 171-179 ; 03783812 (ISSN) ; Azin, R ; Hassanzadeh, H ; Moshfeghian, M ; Sharif University of Technology
2010
Abstract
Estimating the feasibility of acid gas geological disposal requires the knowledge of the water content of the gas phase at moderate pressures and temperatures (typically below 50MPa, below 380K) and up to 6mol NaCl. In this paper, a non-iterative model is developed to predict the water content of sour and acid gases at equilibrium with pure water and brine. This model is based on equating the chemical potential of water and using the modified Redlich-Kwong equation of state to calculate the fugacity of the gas phase. The water content of pure CH4, CO2 and H2S are represented with average absolute deviations of less than 3.36, 7.04 and 8.4%, respectively. Experimental data of the water...
Comparative analysis of hydrate formation pressure applying cubic equations of state (eos), artificial neural network (ann) and adaptive neuro-fuzzy inference system (anfis)
, Article International Journal of Thermodynamics ; Volume 15, Issue 2 , 2012 , Pages 91-101 ; 13019724 (ISSN) ; Saber, M ; Ameri, A ; Sharif University of Technology
Abstract
The objective of this work is making comparison between thermodynamic models and data-driven techniques accuracy in prediction of hydrate formation pressure as a function of temperature and composition of gas mixtures. The Peng-Robinson (PR) and Patel-Teja (PT) equations of state are used for thermodynamic modeling and Artificial Neural Networks (ANNs) and Adaptive Neuro-Fuzzy Inference System (ANFIS) are used as data-driven models. The capability of each method is evaluated by comparison with the experimental data collected from literature. It is shown that there is a good agreement between thermodynamic modeling and the experimental data in most of the cases; however, the prediction...
On the sensitivity of the nanostructural parameters on youngg"s modulus of PLSNs in fully intercalated structures
, Article Journal of Composite Materials ; Volume 43, Issue 24 , 2009 , Pages 2921-2941 ; 00219983 (ISSN) ; Bagheri, R ; Kazeminezhad, M ; Sharif University of Technology
2009
Abstract
Polymer-layered silicate nanocomposites have been observed to demonstrate enhanced mechanical properties particularly at low weight fractions of silicate. Experimental and theoretical investigations reveal that numerous structural parameters strongly influence the modulus of such nanocomposites. A multiscale micromechanical model is developed which considers a wide range of different affecting parameters including the particle aspect ratio, the number of silicate layers per stack, the d-spacing ratio between the layers, the penetration of polymer chains along silicate sheets, the intercalation feature, and the particle volume fraction. The developed model illustrates the accuracy and...
Study of junction and bias parameters in readout of phase qubits
, Article Physica C: Superconductivity and its Applications ; Volume 475 , 2012 , Pages 60-68 ; 09214534 (ISSN) ; Safaei, S ; Khorasani, S ; Fardmanesh, M ; Sharif University of Technology
2012
Abstract
The exact numerical solution of the nonlinear Ginzburg-Landau equation for Josephson junctions is obtained, from which the precise nontrivial current density and effective potential of the Josephson junctions are found. Based on the resulting potential well, the tunneling probabilities of the associated bound states are computed which are in complete agreement with the reported experimental data. The effects of junction and bias parameters such as thickness of the insulating barrier, cross sectional area, bias current, and magnetic field are fully investigated using a successive perturbation approach. We define and compute figures of merit for achieving optimal operation of phase qubits and...
Experimental investigation of forced convective heat transfer coefficient in nanofluids of Al2O3/EG and CuO/EG in a double pipe and plate heat exchangers under turbulent flow
, Article Experimental Thermal and Fluid Science ; Volume 35, Issue 3 , April , 2011 , Pages 495-502 ; 08941777 (ISSN) ; Oskouie, S. N ; Doosthoseini, A ; Joneidi, A ; Pazouki, M ; Sharif University of Technology
2011
Abstract
Nanofluid is the term applied to a suspension of solid, nanometer-sized particles in conventional fluids; the most prominent features of such fluids include enhanced heat characteristics, such as convective heat transfer coefficient, in comparison to the base fluid without considerable alterations in physical and chemical properties. In this study, nanofluids of aluminum oxide and copper oxide were prepared in ethylene glycol separately. The effect of forced convective heat transfer coefficient in turbulent flow was calculated using a double pipe and plate heat exchangers. Furthermore, we calculated the forced convective heat transfer coefficient of the nanofluids using theoretical...
A new empirical correlation for predicting effective molecular diffusivity of gas-heavy oil-porous media systems
, Article Special Topics and Reviews in Porous Media ; Volume 3, Issue 1 , 2012 , Pages 23-33 ; 21514798 (ISSN) ; Mirjordavi, N ; Kazemeini, M ; Ghazanfari, M. H ; Sharif University of Technology
2012
Abstract
Molecular diffusivity is an essential parameter for modeling of mass transfer in enhanced oil recovery processes. However, experimentally determined diffusivities for light gas-heavy oil systems in the presence of porous media are relatively rare. A few correlations are available in the literature that predict diffusivity of gases into heavy oil in presence of porous media. In this work the pressure-decay method was applied to obtain effective molecular diffusion of CO 2, CH 4 and N 2-heavy oil systems in both bulk and porous media systems at different temperatures. The diffusivity of gases in heavy oil was determined by matching the numerically calculated pressures to the measured data. A...
Experimental comparison of some phenomenological hysteresis models in characterizing hysteresis behavior of shape memory alloy actuators
, Article Journal of Intelligent Material Systems and Structures ; Volume 23, Issue 12 , 2012 , Pages 1287-1309 ; 1045389X (ISSN) ; Sayyaadi, H ; Sharif University of Technology
SAGE
2012
Abstract
Among the phenomenological hysteresis models, the Preisach model, Krasnosel'skii-Pokrovskii model, and Prandtl-Ishlinskii model have found extensive applications for modeling hysteresis in shape memory alloys and other smart actuators. Since the mathematical complexity of the identification and inversion problem depends directly on the type of phenomenological hysteresis modeling method, choosing a proper phenomenological model among the mentioned models for modeling the hysteretic behavior of shape memory alloy actuators is a task of crucial importance. Moreover, the accuracy of the hysteresis modeling method in characterizing shape memory alloy hysteretic behavior consequently affects the...
Experimental study and modelling of saturation molality of NaCl in quaternary aqueous electrolyte solutions at various temperatures
, Article Desalination ; Volume 267, Issue 2-3 , February , 2011 , Pages 228-232 ; 00119164 (ISSN) ; Roayaei, E ; Taghikhani, V ; Safekordi, A ; Zahedzadeh, M ; Sharif University of Technology
2011
Abstract
Saturation molality of sodium chloride in mixed aqueous electrolyte solutions containing NaCl, CaSO4 and Na2SO4 was measured at atmospheric pressure over the wide range of temperatures using an equilibrium cell equipped with an accurate temperature control system. The measurements were carried out at different CaSO4 and Na2SO4 concentrations. In order to check the repeatability of the experimental data for the saturation molality of NaCl, the experiments were replicated three times and the values reported were the average of the replicas. To model the data generated in this work, the PDH+UNIFAC-Dortmund activity coefficient model was used. The model used to predict the mean ionic activity...
Experimental investigation and theoretical prediction of extrudate swell using conformational rheological models
, Article International Polymer Processing ; Volume 27, Issue 4 , 2012 , Pages 478-485 ; 0930777X (ISSN) ; Ahmad Ramazani, S. A ; Amoli, H. H ; Kamyabi, A ; Sharif University of Technology
Hanser
2012
Abstract
In this study the extrudate swell of polymer solutions is estimated using the microstructure of polymer molecules. When a flexible polymer chain goes through a narrow die shear stress exerting on the chain will cause the polymer chain to be stretched along the flow direction. After emerging from die all external stresses vanish immediately and the chains tend to recover their previous state due to elastic recovery. This phenomenon will results in a gradual increase in extrudate diameter and this is used as the key idea for estimating swell ratio. A Giesekus based conformational model was used in order to predict polymer chains microstructure everywhere in the domain. The resulting PDE set...
Incorporating multiscale micromechanical approach into PLSNs with different intercalated morphologies
, Article Journal of Applied Polymer Science ; Volume 119, Issue 6 , September , 2011 , Pages 3347-3359 ; 00218995 (ISSN) ; Bagheri, R ; Kazeminezhad, M ; Heidarian, D ; Sharif University of Technology
2011
Abstract
The objective of the present study is to predict Young's modulus of polymer-layered silicate nanocomposites (PLSNs) containing fully intercalated structures. The particular contribution of this article is to consider the changes in structural parameters of different intercalated morphologies in vicinity of each other. These parameters include aspect ratio of intercalated stacks, number of silicate layers per stack, d-spacing between the layers, modulus of the gallery phase, and volume fraction of each intercalated morphology. To do this, the effective particle concept has been employed and combined with the Mori-Tanaka micromechanical model. It has been shown that the simultaneous effects of...
Hot ductility of a Fe-Ni-Co alloy in cast and wrought conditions
, Article Materials and Design ; Volume 32, Issue 5 , 2011 , Pages 2956-2962 ; 02641275 (ISSN) ; Abbasi, S. M ; Momeni, A ; Karimi Taheri, A ; Sharif University of Technology
2011
Abstract
The hot ductility of Fe-29Ni-17Co alloy was studied in both cast and wrought conditions by hot tensile tests over temperature range of 900-1250°C and at strain rates of 0.001-1s-1. Over the studied temperature range, the wrought alloy represented higher elongation and reduction in area as compared to the cast alloy. Dynamic recrystallization was found responsible for the higher hot ductility of the wrought alloy and the improvement of hot ductility of the cast alloy at high temperatures. At temperature range of 1000-1150°C the wrought alloy exhibited a hot ductility drop while a similar trough was not observed in case of the cast alloy. It was also found that at temperatures of 1150-1250°C...
Simulation of wave generated by landslides in Maku dam reservoir
, Article Prediction and Simulation Methods for Geohazard Mitigation - Proceedings of the International Symposium on Prediction and Simulation Methods for Geohazard Mitigation, IS-KYOTO 2009, 25 May 2009 through 27 May 2009 ; 2009 , Pages 91-96 ; 9780415804820 (ISBN) ; Ataie Ashtiani, B ; Sharif University of Technology
Abstract
In this work, impulsive wave generation and propagation generated by landslides are studied numerically for a real case. Maku dam reservoir, in the northwestern of Iran is considered as the case study. Generated wave heights, wave run-up, maximum wave height above the dam crest and the probable overtopping volume have been evaluated, using a two-dimensional numerical model (LS3D). This model is validated using available three-dimensional experimental data for simulating impulsive wave caused by sub-aerial landslides. Based on the results, the generated wave height for first and second scenarios are 12 m and 18 m respectively. The wave height of 8 m is observed close to dam body. Because of...
Application of artificial neural network to estimate the fatigue life of shot peened Ti-6Al-4V ELI alloy
, Article Fatigue of Materials: Advances and Emergences in Understanding, Held During Materials Science and Technology 2010, MS and T'10, 17 October 2010 through 21 October 2010 ; 2010 , Pages 411-417 ; 9780470943182 (ISBN) ; Saeidi, N ; Maddah Hosseini, S. H ; Sharif University of Technology
Abstract
An artificial neural network to predict the fatigue life, residual stress and Almen intensity of shot peened alloy Ti6Al4V ELI was developed. To minimize the prediction error, a feed forward model was used and the neural network was trained with back-propagation learning Algorithm. The results of this investigation show that a neural network with one hidden layer and five neurons in this layer will give the best performance. With this structure the network approaches to the desired error in the least time. Furthermore, it was concluded that there is a good agreement between the experimental data, the predicted values and the well-trained neural network. Therefore, the neural network has a...
A semiclassical approach for the phase matching effect in the nonlinear optical phenomena
, Article Journal of Optics A: Pure and Applied Optics ; Volume 10, Issue 12 , 2008 ; 14644258 (ISSN) ; Kaatuzian, H ; Amjadi, A ; Sharif University of Technology
2008
Abstract
In this paper we present a semiclassical model for explanation of the nonlinear optical effect and phase matching. We calculate momentary quantities of the delay time of photon-electron interaction in each layer. We show that for phase matching, the average delay time for the fundamental photons must be equal to the average delay time for the harmonic photons. Additionally, we calculate the number of layers that the harmonic photon needs to be absorbed or converted to fundamental photons. This calculation applies to different wavelengths with different phase matching angles. Our simulation results are in good agreement with experimental data. © 2008 IOP Publishing Ltd
Direct conversion of methane to methanol over v 2O 5/Sio 2 catalyst in a fixed-bed reactor utilizing a CFD model
, Article World Academy of Science, Engineering and Technology ; Volume 73 , 2011 , Pages 797-802 ; 2010376X (ISSN) ; Morteza, S ; Fattahi, M ; Sharif University of Technology
Abstract
A dynamic model of oxidation of methane to methanol has been developed in a fixed-bed reactor applying V2O5/SiO2 as the reaction catalyst. The standard k-? model with 10% turbulence amount performed. The effects of temperature (450- 500°C) and pressure (20-120 bar) with residence time of 3 seconds, on methane conversion and methanol or formaldehyde selectivity examined. Oxygen used as an oxidant and the amount of oxygen in feed was 5% mol/mol of methane amount. The results showed with increasing the conversion of methane from 0.66 to 1.52%, the selectivity to methanol decreased from 93.4% to 91.9%. The CFD modeling results showed reasonable agreement with the obtained experimental data of...
Equilibrium modeling of xylene adsorption on molecular sieves
, Article Fluid Phase Equilibria ; Volume 298, Issue 1 , November , 2010 , Pages 54-59 ; 03783812 (ISSN) ; Baghalha, M ; Khorasheh, F ; Behvandi, A ; Sharif University of Technology
2010
Abstract
The separation of xylene isomers is an important application in separation processes that is based on their adsorption properties on different adsorbents. In this work, the Price and Danner method was employed with a neural network to investigate the adsorption behavior of binary systems of p-xylene/m-xylene, p-diethyl benzene/m-xylene, and p-diethyl benzene/p-xylene and the ternary system of p-diethyl benzene/m-xylene/p-xylene at 130 and 175°C. The Redlich-Kister, Wilson, and NRTL models were used to determine the activity coefficients in the adsorbed phase. Comparison with experimental data from the literature indicated that the proposed thermodynamic model would best determine surface...
Prediction of asphaltene precipitation during solvent/CO2 injection conditions: A comparative study on thermodynamic micellization model with a different characterization approach and solid model
, Article Journal of Canadian Petroleum Technology ; Vol. 50, issue. 3 , March , 2011 , p. 65-74 ; Masihi, M ; Ghazanfari, M. H ; Kharrat, R ; Sharif University of Technology
Abstract
There are different thermodynamic models that have been applied for modelling of asphaltene precipitation caused by various reasons, such as solvent/CO2 injection and pressure depletion. In this work, two computer codes based on two different asphaltene precipitation thermodynamic models-the first being the thermodynamic micellization model with a different characterization approach and the second being the solid model-have been developed and used for predicting asphaltene precipitation data reported in the literature as well as in the obtained data for Sarvak reservoir crude, which is one of the most potentially problematic Iranian heavy oil reserves under gas injection conditions. For the...