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zamanian--mostafa
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Experimental study of stress anisotropy and noncoaxiality of dense sand subjected to monotonic and cyclic loading
, Article Transportation Geotechnics ; Volume 23 , 2020 ; Jafarzadeh, F ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
The noncoaxiality of the principal stress direction and plastic principal strain increment has been broadly recognized as an influencing parameter for design of soil structures. Here we performed a series of systematic hollow cylinder experiments to study the effects of stress anisotropy on the noncoaxiality of dense Babolsar and Toyoura sands. A total of 25 undrained torsional shear tests were carried out under constant mean confining pressure, and fixed principal stress directions, α. We investigated the stress-strain behavior of dense sands for different α-directions, and cyclic stress ratio, CSR, under monotonic and cyclic loading conditions. The results show that the noncoaxiality value...
Evaluation of the Effect of Anisotropy on Cyclic Behavior of Sands with Hollow Cylinder Apparatus
, Ph.D. Dissertation Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor)
Abstract
Direction of loading and magnitude of the intermediate principal stress have significant effect on the soil responses. In many of in-situ loading the direction of major principal stress is not coincide to the deposition direction of the soil. Also, the magnitude of the intermediate principal stress should be exerted in the three dimensional loading condition. A reliable assessment of the soil behavior and a good estimation of the soil parameters need to do tests in similar condition with in-situ. So the testing apparatus should be able to control the loading direction in various stress paths. Typical equipments used in the geotechnical laboratory have not the ability to control the magnitude...
Initial Blank Design of Deep Drawn Single Layer Composite parts Using Inverse Finite Element Method
, M.Sc. Thesis Sharif University of Technology ; Assempour, Ahmad (Supervisor)
Abstract
The inverse finite element method was derived from ideal forming to predict the development blank of sheet forming process and the strain distribution according to the geometry of final product. In this project we present an inverse finite element method to obtain strain and stress distribution in final shape and design initial blank of deep drawing process. The procedure is as follows: First, strain distribution in deep drawn part is estimated by kinematics. Then by using Hill’s anisotropic plasticity and according to the associated plastic flow rule, stress distribution is obtained in deep drawn orthotropic part.Finally, initial blank is designed by considering external forces between...
The inverse finite element method was derived from ideal forming to predict the development blank of sheet forming process and the strain distribution according to the geometry of final product. In this project we present an inverse finite element method to obtain strain and stress distribution in final shape and design initial blank of deep drawing process. The procedure is as follows: First, strain distribution in deep drawn part is estimated by kinematics. Then by using Hill’s anisotropic plasticity and according to the associated plastic flow rule, stress distribution is obtained in deep drawn orthotropic part.Finally, initial blank is designed by considering external forces between...
Synthesis of titanium oxide nanotubes and their decoration by MnO nanoparticles for biomedical applications
, Article Ceramics International ; Volume 45, Issue 15 , 2019 , Pages 19275-19282 ; 02728842 (ISSN) ; Mahmoudi, P ; Zamanian, A ; Mozafari, M ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this study, apatite formation ability on TiO2 nanotubes (TNTs) synthesized by anodizing process were compared with TNTs decorated by MnO nanoparticles. The MnO nanoparticles used for decoration process were fabricated via thermal decomposition method. At first, it was strived to find the optimal condition of anodizing process and the effect of applied voltages (15 V, 20 V, and 25 V) and process times (15 min, 20 min, and 25 min) on the diameter of the synthesized TNTs was investigated. Results of microscopic characterizations showed that the completely uniform structure of nanotubes with a diameter in the range of about 100–130 nm was achieved after 20 min of anodizing process at an...
The determination of effective diffusivity coefficients in a solvent gas heavy oil system for methane
, Article Petroleum Science and Technology ; Volume 30, Issue 24 , 2012 , Pages 2582-2593 ; 10916466 (ISSN) ; Dadvar, M ; Kharrat, R ; Ghazanfari, M. H ; Sharif University of Technology
2012
Abstract
In this investigation, an accurate high pressure and temperature diffusion setup was applied to measure the diffusion coefficients of methane in Iranian heavy oils in presence and absence of porous media by using the pressure-decay method. The solvent diffusivity in heavy oil was determined by both graphical and numerical methods. In addition, the effects of the porous medium and the temperature on the molecular diffusion coefficient of the solvent gas in the liquid phase were discussed and finally, using experimental data, a functionality dependence of molecular diffusivity on temperature and porous medium characteristics was proposed
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...
Simulation and Optimization of Biogas Production Via Anaerobic Digestion of Biomass
, M.Sc. Thesis Sharif University of Technology ; Rashtchian, Davoud (Supervisor) ; Askaripour, Hossein (Supervisor)
Abstract
Biogas, a mixture of methane and carbon dioxide, is produced through the anaerobic digestion of organic materials where microorganisms, under oxygen-free conditions, convert organic materials through four stages: hydrolysis, acidogenesis, acetogenesis, and methanogenesis. This renewable and sustainable energy source significantly contributes to reducing dependence on fossil fuels, decreasing greenhouse gas emissions, managing organic waste effectively, and preventing soil and water pollution. In this study, the ADM1 model was used to simulate the conversion of organic materials into biogas, with simulations conducted using Aspen Plus and MATLAB software. The system simulated consists of two...
Periodic solutions for a semi-ratio-dependent predator-prey dynamical system with a class of functional responses on time scales
, Article Discrete and Continuous Dynamical Systems - Series B ; Volume 9, Issue 2 , 2008 , Pages 267-279 ; 15313492 (ISSN) ; Hesaaraki, M ; Sharif University of Technology
2008
Abstract
In this paper we explore the existence of periodic solutions of a nonautonomous semi-ratio-dependent predator-prey dynamical system with functional responses on time scales. To illustrate the utility of this work, we should mention that, in our results this system with a large class of monotone functional responses, always has at least one periodic solution. For instance, this system with some celebrated functional responses such as Holling type-II (or Michaelis-Menten), Holling type-III, Ivlev, mx (Holling type I), sigmoidal [e.g., Real and mx2/((A + x)(B +x))] and some other monotone functions, has always at least one ω-periodic solution. Besides, for some well-known functional responses...
Modified Load Scheduling Using Smart Meters
, M.Sc. Thesis Sharif University of Technology ; Parniani, Mostafa (Supervisor)
Abstract
Implementation of various incentive-based demand response strategies has great potential to decrease peak load growth and customer electricity bill cost. Using advanced metering and automatic demand management makes it possible to optimize energy consumption, to reduce grid loss, and to release generation capacities for the sake of providing sustainable electricity supply, and reducing electricity bills for the customers. With these objectives, this thesis examines the previously suggested load scheduling programs in both residential and industrial sectors, and proposes new practical strategies for load management. This thesis has mainly focuses on three subdivisions of load management...
The Analysis of Total Productive Maintenance Based on Computerized Maintenance Management System
, M.Sc. Thesis Sharif University of Technology ; mostafavi, mostafa (Supervisor)
Abstract
The main purpose of this thesis is to analyze the total productive maintenance based on computerized maintenance management system. At first, a detailed study on total productive maintenance is performed and then the requirements of this maintenance strategy are specified. Also, a computerized maintenance management system is defined which can help total productive maintenance to reach to its requirements. Finally, a conceptual model and entity-relationship model for computerized maintenance management system data base has been created
Study of HVDC Transmission for Offshore Wind Farms Based on Voltage Source Converters
, M.Sc. Thesis Sharif University of Technology ; Parniani, Mostafa (Supervisor)
Abstract
In this thesis, DC transmission of offshore wind farms is studied thoroughly. Various system configurations that are introduced in the literatures are discussed and their control scheme for normal conditions and grid faults are studied. Then, the HVDC transmission based on voltage source converter, located between a local offshore ac grid and the onshore ac system is investigated as the most practical choice. The HVDC linke circuit elements are calculated and the control strategies of the offshore and onshore converters are introduced. DFIGs are considered to be the best choice for the offshore wind turbine generators. Then, the system is simulated and the frequency of the offshore grid is...
Feasibility Study of Producing Active Pharmaceutical Ingredient from Conceptual Process to Mass Production-Case Study
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
The main aim of this thesis is to develop the technical knowledge of designing and making active ingredients of domestically produced drugs, decreasing the costs, independency in producing these products, and checking outflow of currency. It also aims to reduce the financial challenges of patients who have to pay huge amounts for such drugs. Conducting research in the field of reverse engineering and using its definition, and attempt in made to get knowledge into the stages of product development process, to determine the technical standards associated with each stage, to recognize how knowledge is shared during this process, and to present some methods of establishing the infrastructure...
Performance Improvement of Maximum Power Point Tracker in Grid-Connected Photovoltaic Systems
, M.Sc. Thesis Sharif University of Technology ; Parniani, Mostafa (Supervisor)
Abstract
Increase in growing concerns over environmental pollution and depletion of fossil fuel resources motivate the need for cleaner energy technologies and stimulate research in facilitating renewable energy systems. In recent years, photovoltaic systems have attracted great attention since they remove the need for energy storage systems and intermediate processess for energy conversion. However, high capital cost, low efficiency and low energy density per area of these systems, as compared with other technologies hinder its industrial use. To surmount these bottlenecks and improve technical performance of PV systems, it is crucial to optimize configuration of convertor connection and to improve...
Coordinated Voltage Control of Power Systems in Normal and Emergency Operation States
, Ph.D. Dissertation Sharif University of Technology ; Parniani, Mostafa (Supervisor)
Abstract
One of the main objectives in operating a power system is to maintain the system voltage properly to avoid equipment damage and transfer power efficiently. Automatic control of transmission network voltage provides significant improvements in security, quality and efficiency of power system operation. This thesis investigates coordinated voltage control of power systems in normal, alert and emergency states. The aim is to propose a comprehensive framework for real-time operation of practical power systems, ensuring secure operation of the system in the normal state and after occurrence of sever contingencies.
At the first, a new coordinated voltage control scheme is proposed to ensure...
At the first, a new coordinated voltage control scheme is proposed to ensure...
The Analysis of Knowledge Management, Dimensions and Implementation Methods-Case study: Sardsaz Khodro Ind. Co
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
Today, organizations are surrounded by basic and continuous changes such as declining organizational resources, reduction of the production cycles, and the need for rapid adaption. Those organizations remain competitive while maintaining their productivity, that have following characteristics: accurately plan and assess their knowledge resources, create and absorb beneficial knowledge, store and organize their knowledge, disseminate knowledge to needed areas, and use knowledge in practice and decision making, to improve their products/services as well as their performance. Therefore, the human capital has been considered as knowledge owners and the most important organizational resource, on...
Feyerabend’s Point of View on Scientific Progress
, M.Sc. Thesis Sharif University of Technology ; Taghavi, Mostafa (Supervisor)
Abstract
Feyarabend’s philosophy of science is against method and rule such that he believes that “anything goes”. However, he sometimes applies the term “progress”. Reviewing his publications shows that from his point of view, progress is qualitative and relative. So, unlike other philosophers of science Feyarabend ignores the clarification of the concept; subsequently, his applications of the term “progress” are somewhat ambiguous. However, by studying his philosophy, one may realize what should be done to achieve progress in any sense. The affirmative aspect of Feyerabend’s philosophy, while highlights the social and ethical elements, considering his humanitarian outlook as well as his special...
Analyzing the Healthcare Wastes and Feasibility Study of Related Items (Plastics)
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
Increasing population and competition for producing various productions and also more consumption in recent decades, result in producing more wastes. Therefore effective and continuous waste management is essential for monitoring the process (from the wastes generation source to the waste disposal) and establishing the efficient strategies to reduce wastes. One of the major sources of waste generation is hospitals that cause lots of environmental problem unless they are managed properly.Recycling is an important element of waste management that can reduce costs by innovative and proper management. The purpose of this research is identification of recyclable plastic items and estimates the...
Analyzing Cost Engineering Along With Presenting A Model To Reduce Cost Of industrial Products
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
Lack of financial sources for production and performing projects has been an effective issue in all governmental and non-governmental organizations. So, using a structure with capability of detecting and forecasting all expenses and costs, and being able to convert the mass of data into useful and instrumental reports for managerial decision such as estimating total cost, selecting the syntax of production and etc is obvious for recourse management of every organization. Among the various components of the cost engineering system, cost management system by recording and allocating cost is an important issue in efficiency of every cost engineering system.In this thesis, Automotive Industrial...
Feasibility Study of Manufacturing of Disposable Plant Containers
,
M.Sc. Thesis
Sharif University of Technology
;
Mostafavi, Mostafa
(Supervisor)
Abstract
Although laws vary in the competitive business world of today and the changing supply and demand parameters show that the process of delivering new products to market is very important.Most organizations today have found that spending more than ever on trusting in traditional competitive levers such as quality, cost reduction and differentiation in selling more products and services are not enough to be successful in market, instead notions such as speed, flexibility andagility can have a significant trend toward offering new products and services. There aresome good reasons for knew that organizations need new ways to develop their new products to survival, compete with its competitors and...
Research to Provide Iranian Customer Satisfaction Index Model in Industry, Case Study: Iran Khodro Co., Golrang Co. and Kaleh Co
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
In recent decades many countries have attempted to measure and formulate customer satisfaction index (CSI), as an important factor in micro and macro-economic level. In developed country CSI has the same value of GNP. Customer Satisfaction Index model actually represents the relationship between primary factors of satisfaction and satisfaction results in the macro level for a country and includes all business aspects. In many countries, industrial companies have a wide range of products and providing Customer Satisfaction Index model for this aspect which can be a base of presenting national customer satisfaction index model. Accordingly, the main goal of this study is providing an Iranian...