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An Investigation on Aging of Rubber Compounds Against Acidic Gases
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Abbas (Supervisor) ; Shojaei, Akbar (Supervisor)
Abstract
Aging of rubber compounds at high temperature and pressure acidic gas is a challenge for using them for a long time. Therefore, in this thesis aging of NBR/PVC compounds against H¬2S and CO2 has been investigated. The main method have been used is Full Factorial Design of Experiment. The parameters have been examined are content of zinc oxide, plasticizer RPO ASTM 290 and antioxidant 4010 NA. The content have been set in tow levels and effect of each have investigated in ambient and 120 degree of centigrad temperature. The results show that the effect of antioxidant 4010 NA on aging of compounds is negative and zinc oxide and plasticizer RPO ASTM 290 are positive
Numerical Study of Various Parameters on Blasting Gases and Dust Ventilation in Mines
, M.Sc. Thesis Sharif University of Technology ; Farhanieh, Bijan (Supervisor)
Abstract
One of the methods of drilling coal mines is mine blasting (drilling with explosives). In this method, explosives such as dynamite are used to excavate the mine and destroy the coal seams. During this type of drilling, in addition to dust, dangerous toxic gases are also produced, so quick and proper ventilation of mine tunnels is necessary in this type of drilling.Depending on the type of mining, the required ventilation system may be different. For example, if the drilling method is long-term method, the mine ventilation is of the U type, but if the mine drilling is the sub-level caving type, auxiliary ventilation is used.In this study, the method of mining is sub-level caving, so that one...
Modelling the Interaction Between Electricity Supply System and Climate Change: the Case Study of Iran
, M.Sc. Thesis Sharif University of Technology ; Saboohi, Yadollah (Supervisor)
Abstract
The power supply system is one of the most important and complex systems. Various factors affect this system. Climate change affects different parts of the power supply system. In this study, the effect of climate change on electricity demand and electricity supply system has been investigated by considering the limited water resources. The amount of water withdrawal and GHG emissions in different scenarios. Scenarios are considered in such a way that assess the probable rising prices of fuels and water, and carbon taxes at three levels. Also, scenarios of rising water prices have been considered to evaluate the effect of this policy alone. It is worth noting that power plants are modeled...
Experimental Study of the Aging Effect on the Oxidation Catalyst Performance as an Emission Control Device for 4-stroke Gasoline Carburetor Motorcycles
, M.Sc. Thesis Sharif University of Technology ; Hamzehlouyan, Tayebeh (Supervisor)
Abstract
There are more than one million motorcycles in the city of Tehran that are responsible for significant amounts of various air pollutants emissions such as carbon monoxide and hydrocarbons. Oxidation catalysis, as the exhaust aftertreatment system of motorcycles, can reduce the emission of CO and hydrocarbon pollutants. The efficiency of these catalysts under typical operating conditions of vehicle exhaust gas has been studied in the literature. However, due to the specific features of motorcycles exhaust gas in Tehran, such as ultra-rich combustion, low air to fuel ratio (lambdas as low as 0.6-0.7), different exhaust gas composition and significant amount of lubricating oil consumption,...
Modification of Three-Way Catalyst (Twc)Formulation for Gasoline Vehicles with the Goal of Improving Its Thermal Stability
, M.Sc. Thesis Sharif University of Technology ; Hamzehlouyan, Tayebeh (Supervisor)
Abstract
Vehicle exhaust gas catalysts play a significant role in air pollution control. In order to solve the problems of cold start and limited supply of precious metals, new studies have focused on the development of three-way catalysts for gasoline vehicles with small amounts of precious metals and increase thermal stability. Different metal ions, especially rare earth metals, due to different physical and chemical properties, show different reinforcing effects on the properties of ceria-zirconia-based materials. Previous studies have shown that the enhancing effect of these materials and the ceria-zirconia ratio on catalyst activity and stability, as well as studies on thermal stability at 1050...
A stochastic aggregate production planning model in a green supply chain: Considering flexible lead times, nonlinear purchase and shortage cost functions
, Article European Journal of Operational Research ; Volume 230, Issue 1 , 2013 , Pages 26-41 ; 03772217 (ISSN) ; Baboli, A ; Sazvar, Z ; Sharif University of Technology
2013
Abstract
In this paper we develop a stochastic programming approach to solve a multi-period multi-product multi-site aggregate production planning problem in a green supply chain for a medium-term planning horizon under the assumption of demand uncertainty. The proposed model has the following features: (i) the majority of supply chain cost parameters are considered; (ii) quantity discounts to encourage the producer to order more from the suppliers in one period, instead of splitting the order into periodical small quantities, are considered; (iii) the interrelationship between lead time and transportation cost is considered, as well as that between lead time and greenhouse gas emission level; (iv)...
The gas-oil interfacial behavior during gas injection into an asphaltenic oil reservoir
, Article Journal of Chemical and Engineering Data ; Volume 58, Issue 9 , 2013 , Pages 2513-2526 ; 00219568 (ISSN) ; Mehranbod, N ; Ayatollahi, S ; Sharif University of Technology
2013
Abstract
Oil displacement and recovery efficiency during gas injection depends on the competition between driving forces and capillary resistance that is governed by gas-oil interfacial behavior. Detailed study of the interfacial forces during gas injection is the main objective of this research work. The effects of injecting gas composition and the possibility of asphaltene precipitation in a wide pressure range were determined through comprehensive experimental study. This was performed by measurement of interfacial tension of a highly asphaltenic Iranian crude oil in three surrounding gas mediums. The results showed that as pressure increases, the rate to reach miscibility reduces in the vicinity...
Experimental investigation of near miscibility effect on relative permeability curves
, Article 74th European Association of Geoscientists and Engineers Conference and Exhibition 2012 Incorporating SPE EUROPEC 2012: Responsibly Securing Natural Resources, 4 June 2012 through 7 June 2012 ; June , 2012 , Pages 5469-5474 ; 9781629937908 (ISBN) ; Masihi, M ; Ghazanfari, M. H ; Sharif University of Technology
European Association of Geoscientists and Engineers, EAGE
2012
Abstract
The requirement of reliable relative permeability data is more intensified when the miscibility condition approaches. In this work the relative permeability of CO2 and oil has been measured at different miscibility conditions using conventional methods. Fractured dolomite and sandstone core plugs samples were used in the experiments. Due to some errorful assumptions of conventional methods such as immiscible, incompressible displacement, inverse modeling was used for predicting the reliable relative permeability of oil and gas phases at near miscible condition from measured oil production and pressure drop data. The initial guesses of relative permeabilities were provided from conventional...
Detail study on improving micro/nano gas mixer performances in slip and transitional flow regimes
, Article Sensors and Actuators, B: Chemical ; Volume 218 , October , 2015 , Pages 78-88 ; 09254005 (ISSN) ; Sabouri, M ; Sharif University of Technology
Elsevier
2015
Abstract
The mixer geometry has substantial effect on mixing performance of different micro/nanomixers. Despite past numerous studies dedicated to mixing of liquid flow streams, there are less efforts to investigate the geometry effects on gas mixing performances. In this work, we focus on gas-gas mixing through different micro/nanoscale mixers under slip and transitional flow regimes. We use the direct simulation Monte Carlo (DSMC) method to provide accurate and reliable results in such flow regimes. To extend our study, we implement different geometrical parameters in our consideration including the mixer size, the impact angle between two incoming gas streams, and the contraction height located in...
Correlation and prediction of solubility of CO2 in amine aqueous solutions
, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 29, Issue 1 , 2010 , Pages 111-124 ; 10219986 (ISSN) ; Taghikhani, V ; Ghotbi, C ; Safekordi, A. A ; Najibi, H ; Sharif University of Technology
Abstract
The solubility of CO2 in the primary, secondary, tertiary and sterically hindered amine aqueous solutions at various conditions was studied. In the present work, the Modified Kent-Eisenberg (M-KE), the Extended Debye-Hückel (E-DH) and the Pitzer models were employed to study the solubility of CO2 in amine aqueous solutions. Two explicit equations are presented to evaluate the concentration of H+ as well as the equilibrium constants of protonation reactions for the tertiary and sterically hindered amine aqueous solutions. Using the M-KE model, the equilibrium constants of protonation reactions of amines were correlated in terms of temperature, CO2 partial pressure and amine concentration....
Advances in non-gray radiation calculation in combusting environments using a modified reference approach
, Article Heat and Mass Transfer/Waerme- und Stoffuebertragung ; Volume 54, Issue 9 , 2018 , Pages 2705-2713 ; 09477411 (ISSN) ; Abrar, B ; Sharif University of Technology
Springer Verlag
2018
Abstract
The radiative heat transfer should be calculated very accurately in many combustion domains. This work uses the spectral-line based weighted-sum-of-gray-gases (SLW) model to calculate the radiation heat transfer in a model furnace representing a combustion field with high temperature gradient variations. The past researchers have commonly implemented the reference approach in the SLW model. However, the reference approach produces error because of enforcing a reference temperature to perform the non-gray radiation heat transfer calculations in non-isothermal domains. In this work, we implement a modified reference approach, which reduces such errors in non-gray gas calculations. We show that...
Preparation of sorbitan stearate
, Article 2nd International Multi-Conference on Engineering and Technological Innovation, IMETI 2009, Orlando, FL, 10 July 2009 through 13 July 2009 ; Volume 1 , 2009 , Pages 81-85 ; 193427268X (ISBN); 9781934272688 (ISBN) ; Alemzadeh, I ; Vossoughi, M ; Inter-American Organization for Higher Education (IOHE); International Institute of Informatics and Systemics (IIIS); Journal of Systemics, Informatics and Cybernetics (JSCI) ; Sharif University of Technology
International Institute of Informatics and Cybernetics, IIIC
2009
Abstract
The present paper relates to an improved method for making surfactant esters, especially sorbitan monostearate and tristearate. Sorbitan esters of fatty acid, stéarate are derived from a reaction between sorbitan and fatty acid. Method of sorbitan ester production needs addition of catalyst. Sorbitan stéarate production was studied using chemical catalyst. Two steps process leading sorbitan production under atmospheric and vacuum pressure with acid catalyst resulted dehydrated product at optimal residence time of 195 min at 180°C for atmospheric conditions and optimalresidence time of 150 min at the same temperature respectively. Sorbitan stearate production was studied by utilizing sorbitan...
Sonoluminescence radiation from different concentrations of sulfuric acid
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 80, Issue 4 , 2009 ; 15393755 (ISSN) ; Imani, K ; Silatani, M ; Sharif University of Technology
2009
Abstract
Sonoluminescence (SL) radiation from an argon bubble in water and in different concentrations of sulfuric acid has numerically been studied to quantify the effects of vapor pressure and viscosity of the liquid on cavitation luminescence in a liquid with controllable vapor pressure and viscosity. For the solutions containing the noble gas with low partial pressure (about 4 Torr), it is shown that there exists an optimum acid solution in which both the temperature and the intensity of SL radiation become maximum. The calculations show that the maximum SL radiation is achieved from the solution of around 65% (wt.) H2 SO4, which is in agreement with available experimental results. © 2009 The...
MILP model for integrated expansion planning of multi-carrier active energy systems
, Article IET Generation, Transmission and Distribution ; Volume 13, Issue 7 , 2019 , Pages 1177-1189 ; 17518687 (ISSN) ; Aghaei, J ; Gharehpetian, G. B ; Safdarian, A ; Sharif University of Technology
Institution of Engineering and Technology
2019
Abstract
In growing economic energy systems, the interdependency of various energy infrastructures has led to a change in countries' policies in their expansion planning of energy networks. In this study, a mixed-integer non-linear programming (MINLP) model is proposed for expansion planning of the multi-carrier systems including electricity and gas distribution networks. The optimal planning determines the best location, time, and alternative for network assets in order to minimise investment costs and reduce losses. Also, as another distinctive feature of this study, given the integration of electricity and gas distribution networks and the complexity of the problem, a new MILP model using...
Numerical study of species separation in rarefied gas mixture flow through micronozzles using DSMC
, Article Physics of Fluids ; Volume 31, Issue 4 , 2019 ; 10706631 (ISSN) ; Darbandi, M ; Sharif University of Technology
American Institute of Physics Inc
2019
Abstract
This work investigates the species separation in the rarefied flow of the argon-helium mixture through convergent-divergent micronozzles. Imposing a molecular mass ratio in the order of 10, the flow of this mixture can lead to the formation of serious nonhomogeneous phenomena such as the species separation. This study is performed in the ranges of 2.0-4.0 for the geometrical expansion ratio, 200-400 K for the wall temperature, and 0.003-1.454 for the inlet Knudsen number. The effects of these parameters are examined on the separative performances of micronozzle. The direct simulation Monte Carlo method is selected as the solution method because it can provide reliable solutions in the...
An assessment of shock-disturbances interaction considering real gas effects
, Article Journal of Fluids Engineering, Transactions of the ASME ; Volume 141, Issue 1 , 2019 ; 00982202 (ISSN) ; Rahmani, S ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2019
Abstract
In this study, a theoretical analysis is performed to assess the interaction of freestream disturbances with a plane normal shock considering real gas effects. Such effects are important in a field with high velocities and high temperatures. To perform the theoretical analysis, the downstream disturbances field is expressed as a mathematical function of the upstream one by incorporating real gas effects in the formulation. Here, the linearized one-dimensional perturbed unsteady Euler equations are used for the classification of the downstream/upstream disturbances field and the linearized one-dimensional perturbed Rankine-Hugoniot equations are applied to provide a relationship between the...
Investigation of effective parameters on the performance of the helium liquefaction cycle
, Article International Journal of Heat and Technology ; Volume 37, Issue 4 , 2019 , Pages 1009-1018 ; 03928764 (ISSN) ; Eslami, M ; Afshin, H ; Sharif University of Technology
International Information and Engineering Technology Association
2019
Abstract
Due to its unique properties, helium has wide application in different industries and scientific fields, which has turned it into a strategic material. Helium liquefaction plants include wide temperature range from 300 k to 4.2 k, so these plants have high energy consumption. A lot of studies have done to optimize the operation of these cycles. In this research, an exergy analysis is performed for a liquid helium production plant. The optimal performance of 3 and 4 stage cycles is extracted using parametric study and the results are compared with those of Collins dual-expander cycle. The results show that by increasing the number of cooling stages, not only the compressor optimum discharge...
Numerical study to evaluate soot formation in a jp combustor equipped to different types of swirler
, Article AIAA Propulsion and Energy Forum and Exposition, 2019, 19 August 2019 through 22 August 2019 ; 2019 ; 9781624105906 (ISBN) ; Ghafourizadeh, M ; Schneider, G. E ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc, AIAA
2019
Abstract
This paper is concentrated on soot formation in a JP combustor and it studies the emission in its exhaust gases when the combustor is equipped with different types of exhaust swirler. So, to approve the developed solver, it is required to predict one related flame structure accurately right at the first step. In this regard, we solve a well-documented benchmark test case with available data from experiment. These data are then compared with the current numerical results to evaluate the discrepancies. The comparison indicates that there is good agreement between them. Afterwards, we equip a similar combustor with different types of swirler, simulate the new designed combustor configurations,...
Investigation of effective parameters on the performance of the helium liquefaction cycle
, Article International Journal of Heat and Technology ; Volume 37, Issue 4 , 2019 , Pages 1009-1018 ; 03928764 (ISSN) ; Eslami, M ; Afshin, H ; Sharif University of Technology
International Information and Engineering Technology Association
2019
Abstract
Due to its unique properties, helium has wide application in different industries and scientific fields, which has turned it into a strategic material. Helium liquefaction plants include wide temperature range from 300 k to 4.2 k, so these plants have high energy consumption. A lot of studies have done to optimize the operation of these cycles. In this research, an exergy analysis is performed for a liquid helium production plant. The optimal performance of 3 and 4 stage cycles is extracted using parametric study and the results are compared with those of Collins dual-expander cycle. The results show that by increasing the number of cooling stages, not only the compressor optimum discharge...
Numerical study to evaluate soot formation in a jp combustor equipped to different types of swirler
, Article AIAA Propulsion and Energy Forum and Exposition, 2019, 19 August 2019 through 22 August 2019 ; 2019 ; 9781624105906 (ISBN) ; Ghafourizadeh, M ; Schneider, G. E ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc, AIAA
2019
Abstract
This paper is concentrated on soot formation in a JP combustor and it studies the emission in its exhaust gases when the combustor is equipped with different types of exhaust swirler. So, to approve the developed solver, it is required to predict one related flame structure accurately right at the first step. In this regard, we solve a well-documented benchmark test case with available data from experiment. These data are then compared with the current numerical results to evaluate the discrepancies. The comparison indicates that there is good agreement between them. Afterwards, we equip a similar combustor with different types of swirler, simulate the new designed combustor configurations,...