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ehyaei--ahmad-reza
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Scattering Theory on Locally symmetric Spaces
, M.Sc. Thesis Sharif University of Technology ; Razvan, Mohammad Reza (Supervisor)
Abstract
Scattering theory on locally symmetric space first was studied by Peter Lax and Ralph Phillips. They studied the and develop scattering theory on it. Without the Fourier analysis tools this theory was completed with a lot of computations. In this thesis first we try to construct Fourier analysis by definition Fourier transform then by means of new tools we prove very short version of scattering theory on locally symmetric space . In general case for studying scattering theory we need firs spectral decomposition of Hilbert space of square integrable functions locally symmetric spaces of rational rank one is achieved by quotient of symmetric space where G is Lie group and K is maximal...
Energy, economic and environmental (3E) analysis of a micro gas turbine employed for on-site combined heat and power production
, Article Energy and Buildings ; Volume 42, Issue 2 , 2010 , Pages 259-264 ; 03787788 (ISSN) ; Mozafari, A ; Sharif University of Technology
2010
Abstract
This paper studies the optimization of micro turbine application to meet the electrical, heating and cooling loads of a building by energy, economics and environmental analysis. In this study following three cases are considered: 1: A simple micro gas turbine to meet the electrical power of the building. 2: A simple micro gas turbine to meet the electrical power of the building as well as the power required by heat pump and mechanical refrigerator needed for heating, cooling and domestic hot water (DHW) systems. 3: A CHP micro gas turbine to meet the electrical power of the building as well as part of the power required by heat pump and mechanical refrigerator needed for heating, cooling and...
Selection of micro turbines to meet electrical and thermal energy needs of residential buildings in Iran
, Article Energy and Buildings ; Volume 39, Issue 12 , December , 2007 , Pages 1227-1234 ; 03787788 (ISSN) ; Bahadori, M. N ; Sharif University of Technology
2007
Abstract
Micro gas turbines are considered to meet the electrical, domestic hot water, heating and cooling energy needs of a residential building located in Tehran, Ahvaz and Hamedan. The building is 10 stories high and has a total of 8000 m2 floor area with the peak demands of electricity of 32.96 kW, DHW of 0.926 kW, heating load of 1590 kW and the cooling load of 2028 kW, when the building is located in Tehran. With these demands, 30 micro turbines of 30 kW (nominal power) are needed to meet all the energy needs of the building. The excess electricity generated by the micro turbines is to be used in a heat pump, and the energy in the exhaust gases is to be used to meet other thermal energy needs...
Internalizing the social cost of noise pollution in the cost analysis of electricity generated by wind turbines
, Article Wind Engineering ; Volume 30, Issue 6 , 2006 , Pages 521-529 ; 0309524X (ISSN) ; Bahadori, M. N ; Sharif University of Technology
2006
Abstract
The Social Cost of nuisance noise from a wind turbine is defined here as the additional cost to reduce the noise level at a receptor to an exceptable, non-nuisance value, i.e. to mitigate this cost. This acceptable sound level is considered to be 35 dB. Our example is a 10-kW (nominal power) wind turbine considered to supply the electrical energy needs of a 3-storey residential building in Tehran and Manjil. The turbine generates sound at 75 dB. To reduce the sound level at the third floor of the building to 35 dB, it was necessary to increase the height of the turbine from 24 m to 48 m. The initial installed cost of the turbine thereby increased from US$45.000 to US$55,000. The cost of...
Analysis and Improvement of QoS in Optical CDMA Networks Using Cross Layer Design Concepts
, M.Sc. Thesis Sharif University of Technology ; Pakravan, Mohammad Reza (Supervisor)
Abstract
According to the rapid growing in communication devices, users need higher rates for their usages. Fiber optics is one the major choices to support such rates. One of the simplest and cheapest networks is Local Area Network (LAN) as a Passive Optical Network (PON). In these networks, some computers are locally connected to a passive optical device and communicate through it. Multiple access to a shared channel is an important task in such a network. In this thesis, Code Division Multiple Access (CDMA) is used and a new algorithm for Multiple Access Control Sublayer (MAC) based on scheduling will be developed to improve Quality of Service (QoS) and stabilize the network.
In the scheduling...
In the scheduling...
Optimisation of micro gas turbine by exergy, economic and environmental (3E) analysis
, Article International Journal of Exergy ; Volume 7, Issue 1 , 2010 , Pages 1-19 ; 17428297 (ISSN) ; Ahmadi, A ; Ehyaei, M. A ; Sharif University of Technology
2010
Abstract
This research proposes a new method for optimisation of a power generation system based on exergy fuel cost and external social cost of air pollution. A thermodynamic model is provided to estimate the outlet mass flow rates of CO2, CO, NO and NO2 for a gas turbine based on maximising the first and second law efficiencies and minimising the objective function. Results show that inclusion of the external social cost of air pollution increases the optimum excess air ratio if temperature constraint due to metallurgical consideration is disregarded. Otherwise external social cost of air pollution is independent of optimised conditions
A new proof of FDR control based on forward filtration
, Article Journal of the Iranian Statistical Society ; Volume 19, Issue 1 , 2020 , Pages 59-68 ; Alishahi, K ; Shojaie, A ; Sharif University of Technology
Iranian Statistical Society
2020
Abstract
For multiple testing problems, Benjamini and Hochberg (1995) proposed the false discovery rate (FDR) as an alternative to the family-wise error rate (FWER). Since then, researchers have provided many proofs to control the FDR under dierent assumptions. Storey et al. (2004) showed that the rejection threshold of a BH step-up procedure is a stopping time with respect to the reverse filtration generated by the pvalues and proposed a new proof based on the martingale theory. Following this work, martingale methods have been widely used to establish FDR control in various settings, but have been primarily applied to reverse filtration only. However, forward filtration can be more amenable for...
Exergetic optimization of a PEM fuel cell for domestic hot water heater
, Article Journal of Fuel Cell Science and Technology ; Volume 2, Issue 4 , 2005 , Pages 284-289 ; 1550624X (ISSN) ; Abbassi, A ; Ehyaei, M ; Sharif University of Technology
2005
Abstract
In this paper, a 5 kW PEM fuel cell including burner, steam reformer, and water heater for domestic application has been considered. Water is used for cooling of the fuel cell. Cold water is passed through a cooling channel, warmed up and used for domestic water heating. To increase the efficiency, outlet steam of fuel cell is fed to the reformer. The perfomance of the system is optimized by exergy analysis based on the second law of thermodynamics. Also, the effect of burner, fuel cell temperature and stoichiometric air fuel ratio are investigated. In this analysis, pressure loss in the fuel cell and heat transfer of the cooling channel are taken into account whereas, pressure loss in...
Developing an Applied Model for Energy Management in Dairy Production Industry
, M.Sc. Thesis Sharif University of Technology ; Mokhtar, Ali Reza (Supervisor) ; Miremadi, Ali Reza (Supervisor)
Abstract
Reviewing trends of energy consumption in the world reveals that sooner or later energy resources will be depleted. This concerning rate of consumption has brought about more greenhouse gases (GHG) emission influencing deleteriously on environment and climate. Human has continued energy consumption to maintain and improve the quality of his life through industrial production. Industry as a significant energy user owns considerable contribution to this consumption. Several attempts have been carried out to develop energy management systems in order to improve the energy efficiency of industrial sectors. Whilst they are comprehensive and could be applied to any sector, there is lack of...
Formability analysis of Tailor Welded Blank Pridaction with Friction Stret Weld
, M.Sc. Thesis Sharif University of Technology ; Asempour, Ahmad (Supervisor) ; Naghdabadi, Reza (Supervisor)
Abstract
The Tilor welded blank (TWB) two or more sheets with different thickness or strength which are welded together. The automobile designer are searching for new methods to reduce the cars’ weight and producing cost in order to diminish fuel consumption so they can survive in the competitive market. One way to achieve to this seemingly Contradictory demands, is using TWB in cars’ body. One of the most applicable methods to investigate the formability of metals sheets, is Forming Limit Diagrams (FLD). Three ways to determine the FLD are: Analytical Method, Experimental Methods, and Numerical Method. The experimental method to determine FLD, require metal sheets to undergo in different strain...
Comparing the Performance of Centrifuge, Membrane Filter and Filter Press for Clarification of Lipase Enzyme
, M.Sc. Thesis Sharif University of Technology ; Rousta Azad, Reza (Supervisor)
Abstract
Lipases (Triacyl Glycerol Acyl Hydrolase, EC.3.1.1.3) are multidimensional biocatalysts which have many applications in food industrials, dairy, fats and oils processing, detergents, synthesis of pure chemical and pharmaceutical materials, paper industrial and cosmetics. Generally, industrial enzymes are produced extracellularly, so their separation from a low-cost complex medium (usually used for production) is one of the cost stages in their production process. Filtration is the most economical method of separation in the production of enzymes, but due to the small size of colloidal particles and cell masses present in the fermentation environment, its use is subject to limitations. In...
Exergy, economic & environmental (3E) analysis of inlet fogging for gas turbine power plant
, Article Energy ; Volume 36, Issue 12 , December , 2011 , Pages 6851-6861 ; 03605442 (ISSN) ; Mozafari, A ; Alibiglou, M. H ; Sharif University of Technology
2011
Abstract
In the present paper, the effects of inlet fogging system on the first and second law efficiencies are investigated for a typical power plant (Shahid Rajaee) which is located near Ghazvin in Iran. Also a new function is proposed for system optimization that includes the social cost of air pollution for power generating systems. The new function is based on the first law efficiency, energy cost and the external social cost of air pollution for an operational system. Social cost of air pollution is based on the negative effects of air pollution on the health of society and environment. The economic aspect of these effects is called external social cost of air pollution. Other pollution sources...
Fluid Suspended Films in Present of Electric Field and Voltage
, Ph.D. Dissertation Sharif University of Technology ; Amjadi, Ahmad (Supervisor) ; Ejtehadi, Mohammad Reza ($item.subfieldsMap.e)
Abstract
Scientists want to know how they can control fluids motion. They use electric fields for controlling the fluids in different dimensions. In small size, application of electric fields is very important because of biological applications. We use electric current and field for rotating freely suspended films. Here, we study soap, polar and non-polar liquids, MBBA liquid crystal and ferrofluids films. We show that the surface charge plays the crucial role in rotating the films.We study the correlation between rotation of a film and different physical quantities.Our experiments confirm that dipole moments of fluid molecules do not show a clear effect on the rotation. Increasing the dipole moment...
Stabilization of the Finite element Analysis of the Fluid-Structure Interaction in Micro Systems in Small Time Steps
, Ph.D. Dissertation Sharif University of Technology ; Movahhedy, Mohammad Reza (Supervisor) ; Assempour, Ahmad (Supervisor)
Abstract
Fluid-structure interaction plays an important role in the performance of various Microsystems. In many micro-devices such as micropumps, microvalves and micromixers, the fluid flow is driven by a vibrating solid membrane. Since the fluid also plays a role in resistance to the solid vibration and deformation, the solid vibration and the fluid flow are always coupled and a full fluid-structure interaction (FSI) analysis is required in order to investigate the performance characteristics of these devices. Since the frequency of the solid vibration is normally high in micro-devices, the time step size required for the finite element analysis of the fluid-structure interaction in these devices...
A Fuzzy Multi-Criteria Approach to Sustainable Development Case Study of Hendurabi Island in Iran
,
Ph.D. Dissertation
Sharif University of Technology
;
Abrishamchi, Ahmad
(Supervisor)
;
Maknoon, Reza
(Co-Supervisor)
Abstract
The main objective of this research is to provide a framework by which decision-makers can evaluate and compare alternatives for sustainable development planning under uncertain dynamic future considering the risk and uncertainty associated with human judgment as well as the uncertain future. This approach combines the Delphi method, fuzzy set theory, and a discrete multi-criteria method based on prospect theory (TODIM). TODIM (an acronym in Portuguese for iterative MCDM) method is a particular multi-criteria approach based on the prospect theory. A qualitative Delphi technique is used to identify a set of qualitative sustainability criteria and to rate the alternatives accordingly. The...
Fabrication and Characterization of Porous Carbon-Graphene Composite as an Absorbent for Industrial Pollutants
, Ph.D. Dissertation Sharif University of Technology ; Madaah Hosseini, Hamid Reza (Supervisor) ; Pourjavadi, Ali (Supervisor) ; Bahramian, Ahmad Reza (Co-Supervisor)
Abstract
The amount of fresh water suitable for various uses is decreasing day by day. This may be due to evaporation or contamination of water or such. Heavy metal cations, dyes, oils and solvents are the most important substances that contaminate water. There are various ways to remove these contaminants, one of which is the absorption of these substances by suitable absorbents. Carbon compounds have attracted much attention among all the absorbents used so far. The aim of this study is to produce carbon aerogels from an economic and modify its structure and properties by adding graphene nanosheets. In this study, Novalak-graphene oxide (GO) gel was fabricated using solvent-saturated vapor...
Silver nanoparticles supported on silica-coated ferrite as magnetic and reusable catalysts for oxidant-free alcohol dehydrogenation
, Article RSC Advances ; Volume 5, Issue 29 , Jan , 2015 , Pages 22503-22509 ; 20462069 (ISSN) ; Shakourian Fard, M ; Ehyaei, N ; Mahmoodi Hashemi, M ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
Silver (0) nanoparticles supported on silica-coated ferrite were synthesized to be used as an efficient and recyclable heterogeneous catalyst for oxidant-free dehydrogenation of alcohols to the corresponding carbonyl compounds. The catalyst can be easily recovered and reused for 8 reaction cycles without considerable loss of activity. The facile recovery of the catalyst is carried out by applying an external magnetic device. The catalyst was fully characterized by the techniques of TEM, SEM, XRD, EDS, ICP-AES, and VSM. This journal is
Human Capital Development and Utilization Methodology in a Public Sector Organization: Dynamic Capability Approach
, M.Sc. Thesis Sharif University of Technology ; Kermanshah, Ali (Supervisor) ; Sanjari, Ahmad Reza (Supervisor)
Abstract
It is proposed, in this research, a methodology for a public sector organization to integrate policy making in human capital development and utilization area. In this case the researcher used system dynamics method for modeling and analyzing the situation, to describe the mechanisms that produce the difficulties in the organization. The researcher mentioned the differences between public sector and profit organization, in designing the main part of the model and also the use of dynamic capability approach in designing human capital development parts of it. The model built in this research, describe the events before and after the 1990s separately, according to the different policy making...
Optimal Asset Allocation with Hidden Markov Regime Switching
,
M.Sc. Thesis
Sharif University of Technology
;
Bahramgiri, Mohsen
(Supervisor)
;
Jalali Naeni, Ahmad Reza
(Supervisor)
Abstract
Asset allocation is one of the core economic functions of security markets. By purchasing and selling securities individuals are able to effectively time their stream of consumption and to allocate their temporarily unused wealth among competing investments. To time the stream of future consumption optimally, the question arises as to how wealth is allocated most effciently on security markets. The purpose of this thesis is to develop an optimal Asset Allocation with Hidden Markov Regime Switching means and volatilities. We use the historical weekly information of three Indices in Wallstreet stock exchange: Stock, bond and commodity. First we use these historical information from...
Improvement and Expansion of Characteristic Green’s Function-Complex Images Method for Extraction of Green’s Function of Finite Dielectric Structures
, Ph.D. Dissertation Sharif University of Technology ; Shishegar, Amir Ahmad (Supervisor) ; Faraji-Dana, Reza (Co-Advisor)
Abstract
Finite dielctric structures are commonly used in optical devices, Microwave Integrated Circuitc (MICs) and printed antennas. To analyze these structures, full-wave analysis methods cannot be employed easily. They need huge computer resources and are time-consuming especially for electrically large structures. On the other hand, asymptotic techniques may not be exact enough for these structures. In this thesis, MPIE technique is chosen as an accurate and efficient technique for analyzing these structres. To use this technique, the magnetic vector potential and electric scalar potential are required. Uniform and closed-form spatial Green's function for finite dielectric structures is...