Loading...
Search for:
vakili-nezhaad--g--r
0.257 seconds
Total 9011 records
Salting-out effect of NaCl and KCl on the ternary LLE data for the systems of (water + propionic acid + isopropyl methyl ketone) and of (water + propionic acid + isobutyl methyl ketone)
, Article Journal of Chemical Thermodynamics ; Volume 36, Issue 4 , 2004 , Pages 341-348 ; 00219614 (ISSN) ; Mohsen Nia, M ; Taghikhani, V ; Behpoor, M ; Aghahosseini, M ; Sharif University of Technology
Academic Press
2004
Abstract
(Liquid + liquid) equilibrium (LLE) data were obtained for the ternary systems of {water + propionic acid (PA) + isopropyl methyl ketone (IPMK.)} and of {water + PA + isobutyl methyl ketone (IBMK)} at atmospheric pressure and temperatures (303.15, 313,15 and 323.15) K, respectively. The effect of electrolytes on the LLE data for the ternary systems was also investigated. The results obtained from the experiments showed that the electrolytes studied in this work, i.e., NaCl and KCl significantly affect the solubility of PA in the organic solvents used in the experiments. The results also showed that the distribution coefficients for PA and the selectivity of the solvents in extracting PA,...
Energy system improvement planning under drought condition based on a two-stage optimization model: The desire for sustainability through the promoting of system's resilience
, Article Energy Reports ; Volume 7 , 2021 , Pages 3556-3569 ; 23524847 (ISSN) ; Saboohi, Y ; Tsatsaronis, G ; Vakili, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Energy is one of the most important social and economic infrastructures and human life is strongly depends on it. In recent years, the occurrence of natural disasters such as drought as a high-impact low-probability event is undeniable. So, energy planning in the disruption situation is necessary in order to anticipate and maintain the performance of the energy system in optimal condition. This paper focuses on developing a hybrid long-term framework for evaluating the energy system resilience based on sustainability concept against drought. The model bridges the gap between long-term energy system planning in macro level and short-term switching operations or micro level modeling approach...
Energy system improvement planning under drought condition based on a two-stage optimization model: The desire for sustainability through the promoting of system's resilience
, Article Energy Reports ; Volume 7 , 2021 , Pages 3556-3569 ; 23524847 (ISSN) ; Saboohi, Y ; Tsatsaronis, G ; Vakili, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Energy is one of the most important social and economic infrastructures and human life is strongly depends on it. In recent years, the occurrence of natural disasters such as drought as a high-impact low-probability event is undeniable. So, energy planning in the disruption situation is necessary in order to anticipate and maintain the performance of the energy system in optimal condition. This paper focuses on developing a hybrid long-term framework for evaluating the energy system resilience based on sustainability concept against drought. The model bridges the gap between long-term energy system planning in macro level and short-term switching operations or micro level modeling approach...
Modeling dual-channel supply chain based on fuzzy system and genetic algorithm
, Article International Journal of Uncertainty, Fuzziness and Knowlege-Based Systems ; Volume 25, Issue 4 , 2017 , Pages 573-598 ; 02184885 (ISSN) ; Shavandi, H ; Vakili, M. R ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2017
Abstract
In this paper, we have proposed a dual-channel supply chain model in uncertain environment to analyze the demand of manufacturer and retailer demand in which the profit being maximized. Linguistic terms are also utilized to establish two fuzzy systems for estimating the demand in direct and retail channels. In order to do that, a mathematical model is proposed based on decentralized situation of supply chain. To solve the model, we have developed a hybrid solution method of genetic algorithm, fuzzy system, and L-P metric. Finally, several test problems are first generated; then, the computational results are analyzed. © 2017 World Scientific Publishing Company
Modification of standard k-epsilon turbulence model for multi-element airfoil application using optimization technique
, Article 24th AIAA Applied Aerodynamics Conference, San Francisco, CA, 5 June 2006 through 8 June 2006 ; Volume 1 , 2006 , Pages 216-227 ; 10485953 (ISSN); 1563478129 (ISBN); 9781563478123 (ISBN) ; Setayeshgar, A ; Vakili, S ; Schneider, G. E ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc
2006
Abstract
The use of multi-element airfoils has been known as a major approach to boost up the lift of wing without dramatic increase in its drag. In fact, the configuration helps to reduce the chance of flow separation over the airfoil. However, the use of a complicated geometry such as multi-element airfoil would normally cause complexity in flow behavior. The experience has shown that the flow field complexities cannot be properly modeled using standard two-equation k-epsilon turbulence model. Therefore, it is important to improve the accuracy of general turbulence models in specific applications and complex computational domains. In this work, we extend a suitable objective function based on...
Developing an innovating optimization framework for enhancing the long-term energy system resilience against climate change disruptive events
, Article Energy Strategy Reviews ; Volume 40 , 2022 ; 2211467X (ISSN) ; Fakehi Khorasani, A. H ; Vakili, A ; Saboohi, Y ; Tsatsaronis, G ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The energy system is one of the major sub-sectors of the economy in every society in which both supply with high reliability and compatibility of the energy sector with the environment is a necessity in the process of economic reconstruction and sustainable development. The energy system has been more susceptible to various disruptive events in recent years. Thus, designing a resilient energy system capable of resisting and recovering rapidly from high-impact low-probability (HILP) disruptive events is essential. This paper focuses on developing a two-stage long-term optimization framework for evaluating the energy system resilience as a crucial Critical Infrastructure (CI) system against...
Recommendations on enhancing the efficiency of algebraic multigrid preconditioned GMRES in solving coupled fluid flow equations
, Article Numerical Heat Transfer, Part B: Fundamentals ; Volume 55, Issue 3 , 2009 , Pages 232-256 ; 10407790 (ISSN) ; Darbandi, M ; Sharif University of Technology
2009
Abstract
The algebraic multigrid (AMG) algorithm as a preconditioner to the Krylov subspace methods has drawn the attention of many researchers in solving fluid flow and heat transfer problems. However, the efficient employment of this solver needs experience, because users have to quantify several important parameters. In this work, we choose a hybrid finite-volume element method and quantify the optimum magnitudes for those parameters. To generalize our results, two sets of fluid flow governing equations, the thermobuoyant flow and confined diffusion flame, are studied and the optimum values are determined. The results indicate that the AMG can be very effective if a proper storage method is chosen...
Evaluation of The Informational Efficiency of Tehran Securities Market
, M.Sc. Thesis Sharif University of Technology ; Zamani, Shiva (Supervisor)
Abstract
In the present research, the weak level efficiency of securitise market is reviewed and examined .Therefore the “Random Walk Hypothesis” has been examined on the time series of daily efficiency index of TEHRAN SECURITISE MARKET. The main difference between this research and the previous researches which have been performed previously in Iran, is the method of Hypothesis Test. The” Variance Ratio Test” has been used as a method of Hypothesis’ Test. In the second chapter, the theoretical and experimental literatures of this research has been described in detail. In parallel with the ” Variance Ratio Test”, the impact of the Day of week and the “HETROSCEDASITY TEST” also has been...
Production of Nanostructured Composite Sheets of AA1100/St37 Using ARB Technique and Evaluation of Heat Treatment Effect on Grains Structure
, M.Sc. Thesis Sharif University of Technology ; Asgari, Sirous (Supervisor)
Abstract
In present work, nanostructured multilayer composites produced from AA1100 and St37 alloys and mechanical properties of resulted samples characterized using tension and micro hardness tests. Also dispersion pattern of second phase in matrix studied via optical microscopy. Thickness of second phase layers showed a little reduction after 2 ARB cycles; but their length decrease gradually. With increasing number of ARB cycles up to 6 cycles, sample's tensile strength first decrease rapidly and after that increased, but never reached initial value. In order to evaluation of heat treatment effects on samples grain structure, samples heat treated and tensile test carried on them. Annealing at 300...
Why and How did Philosophy of Science Come to Iran?
, M.Sc. Thesis Sharif University of Technology ; Golshani, Mehdi (Supervisor)
Abstract
The history of an Episteme is part of that Episteme. Without understanding the history of Episteme, one cannot get the right understanding of the Episteme. In order to understand the current coordinates of philosophy in Iran (as well as understanding the current state of philosophy in Iran), it must examine the history of its emergence and development. Part of the sources of recognition of this history is the “Erlbnis” of those who lived the event. Those who have been trying for its birth and development. Some other sources in understanding this history are the previous published works in this area. Another is the educational effort and the establishment and development of the institutions...
Numerical study on split base plate connection with concentric anchors between steel-plate composite wall and concrete basemat
, Article Structural Design of Tall and Special Buildings ; Volume 31, Issue 11 , 2022 ; 15417794 (ISSN) ; Mirghaderi, S. R ; Epackachi, S ; Asgarpoor, M ; Gharavi, A ; Sharif University of Technology
John Wiley and Sons Ltd
2022
Abstract
Steel-plate composite (SC) walls can be connected to a concrete basemat using a base plate and a set of anchors eccentric to the wall. The base plate can be separated into two parts so that the concrete of the wall and basemat is cohesive, and thus, the wall can be manufactured more easily and economically. Additionally, compression and shear demand are directly transferred from infill concrete to concrete basemat. Another change in the base plate connection of available tested walls involves transferring anchors to the bottom of faceplates. As a result of this modification, the base plate is removed from the force transmission chain, and the force is transferred directly from the wall to...
Environmental impact analysis of high-rise buildings for resilient urban development
, Article Scientia Iranica ; Volume 27, Issue 4 , 2020 , Pages 1843-1857 ; Parivar, P ; Sehat Kashani, S ; Farshforoush Imani, A ; Vakili, F ; Ahmadi, G ; Sharif University of Technology
Sharif University of Technology
2020
Abstract
In recent years, the construction of high-rise buildings as an urban development strategy has been accepted in many megacities. High-rise buildings have positive as well as negative impacts on urban environments. Therefore, the environmental impact assessment of high-rise buildings for establishing strategies to ensure sustainable and resilient urban development is essential. In this study, the environmental impact of high-rise buildings with a resilient development mindset was assessed. Resilience mindset provides an approach for including the uncertainties and interdependence of systems and processes for planning new sustainable developments and assessment methods. The corresponding...
Design of adaptive proportional-integral-weighted (PIw) controllers for control of a class of nonlinear uncertain systems
, Article 2017 25th Iranian Conference on Electrical Engineering, ICEE 2017, 2 May 2017 through 4 May 2017 ; 2017 , Pages 923-926 ; 9781509059638 (ISBN) ; Tavazoei, M. S ; Sharif University of Technology
2017
Abstract
Study on the potential abilities of the proportional-integral-weighted (PIw) controllers, as a recently proposed generalization for proportional-integral (PI) controllers, can be useful for improving the performance of traditional control systems. In this paper, adaptive PI and adaptive PIw controllers are designed to be used in control of a special class of nonlinear uncertain systems based on the Lyapanuv stability theorem. The effectiveness of the proposed controllers is illustrated by applying the proposed schemes to a Continuous Stirred-Tank Reactor (CSTR) system with an unknown parameter. Simulation results indicate that using adaptive PIw controllers, in comparison to using the...
Superior anti-biofouling properties of mPEG-modified polyurethane networks via incorporation of a hydrophobic dangling chain
, Article Progress in Organic Coatings ; Volume 158 , September , 2021 ; 03009440 (ISSN) ; Makki, H ; Ghaffarian Anbaran, R ; Vakili, H ; Ghermezcheshme, H ; Zandi, N ; Sharif University of Technology
Elsevier B.V
2021
Abstract
PEG-modification is a proven method to enhance the hydrophilicity, protein resistance, and anti-biofouling properties of polymer coatings. It is considered as the gold standard interfacial modification technique such that the higher PEG content, the higher hydrophilicity, and lower protein adsorption, i.e., the initial stage of the biofouling process. Nevertheless, increasing the PEG content causes a higher water uptake, which declines the polymer mechanical strength and increases its hydrolytic degradation rate. Thus, an effective strategy to produce a limited-water-absorbing PEG-modified polymer is to force the majority of PEG molecules to migrate towards the interfacial region while the...
Type i shell galaxies as a test of gravity models
, Article Astrophysical Journal ; Volume 848, Issue 1 , 2017 ; 0004637X (ISSN) ; Kroupa, P ; Rahvar, S ; Sharif University of Technology
2017
Abstract
Shell galaxies are understood to form through the collision of a dwarf galaxy with an elliptical galaxy. Shell structures and kinematics have been noted to be independent tools to measure the gravitational potential of the shell galaxies. We compare theoretically the formation of shells in Type I shell galaxies in different gravity theories in this work because this is so far missing in the literature. We include Newtonian plus dark halo gravity, and two non-Newtonian gravity models, MOG and MOND, in identical initial systems. We investigate the effect of dynamical friction, which by slowing down the dwarf galaxy in the dark halo models limits the range of shell radii to low values. Under...
Frameworks, quantitative indicators, characters, and modeling approaches to analysis of energy system resilience: A review
, Article Renewable and Sustainable Energy Reviews ; Volume 144 , 2021 ; 13640321 (ISSN) ; Saboohi, Y ; Vakili, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The rise of the damage to energy systems caused by both natural and man-made disruptive events and the connection between energy systems and socio-economic systems have motivated the study of energy system resilience. This paper conceptualizes and comprehensively presents a systematic review of the recent literature focused on the analytical, technical, and mathematical points from the standpoint of the energy systems facing disruptive events. To this end, five phases are developed. Firstly, the concept of the energy system resilience is presented, and then the energy resilience characters and the resilience states are introduced and connected. Thirdly, the formulation and indicators of the...
Frameworks, quantitative indicators, characters, and modeling approaches to analysis of energy system resilience: A review
, Article Renewable and Sustainable Energy Reviews ; Volume 144 , 2021 ; 13640321 (ISSN) ; Saboohi, Y ; Vakili, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The rise of the damage to energy systems caused by both natural and man-made disruptive events and the connection between energy systems and socio-economic systems have motivated the study of energy system resilience. This paper conceptualizes and comprehensively presents a systematic review of the recent literature focused on the analytical, technical, and mathematical points from the standpoint of the energy systems facing disruptive events. To this end, five phases are developed. Firstly, the concept of the energy system resilience is presented, and then the energy resilience characters and the resilience states are introduced and connected. Thirdly, the formulation and indicators of the...
Performance Analysis of PIw Controllers in Improving the Efficiency of Nonlinear Control Systems
, M.Sc. Thesis Sharif University of Technology ; Tavazoei, Mohmmad Saleh (Supervisor)
Abstract
In this thesis, the performance of a special type of controllers, called Proportional-Integral weighted (PIw) controllers, in control of nonlinear systems is studied. To this aim, the domain of attraction of polynomial nonlinear control systems in the presence of PIw and Proportional-Integral (PI) controllers is estimated and compared with each other. For this estimation, two different methods are used, and the obtained results are compared. Next, adaptive PIw and adaptive PI controllers are designed to be used in control of nonlinear systems. The effectiveness of the proposed controllers is illustrated for a Continuous-Stirred-Tank-Reactor (CSTR) that has an uncertain parameter in its...
Data-Oriented Verification of Programs
, M.Sc. Thesis Sharif University of Technology ; Ardeshir, Mohammad (Supervisor)
Abstract
The verification of programs is one of the most important subjects in Computer Science. In this thesis, after reviewing preliminary subjects, While-Programming computational model is presented and its semantics is discussed. Next, the axiomatic method of Hoare is presented, which is a deduction system for verification of programs. With the help of Hoare method, the idea of Data-Oriented verification of programs is developed
Dark energy from fifth-dimensional brans-dicke theory
, Article International Journal of Modern Physics D ; Volume 22, Issue 10 , 2013 ; 02182718 (ISSN) ; Farhoudi, M ; Vakili, H ; Sharif University of Technology
2013
Abstract
Following the approach of the induced-matter theory, we investigate the cosmological implications of a five-dimensional Brans-Dicke (BD) theory, and propose to explain the acceleration of the universe. After inducing in a four-dimensional hypersurface, we classify the energy-momentum tensor into two parts in a way that, one part represents all kind of the matter (the baryonic and dark) and the other one contains every extra terms emerging from the scale factor of the fifth dimension and the scalar field, which we consider as the energy-momentum tensor of dark energy. We also separate the energy-momentum conservation equation into two conservation equations, one for matter and the other for...