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khodadadi-daryan--monireh
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Experimental study of Silver, Zinc and Copper ablation by Nd:YAG laser
, M.Sc. Thesis Sharif University of Technology ; Saddighi, Rasoul (Supervisor)
Abstract
In this project, production of nano and micro particles with laser ablation of zinc, silver and copper sheet metals in the liquid medium has been experimentally studied. For this aim, homemade Nd:YAG pulsed laser at 1064nm wavelength, 60μs pulses with excellent stability with energies up to 700mj is used. By changing the pulse intensity on the target surface, the parameters such as size, shape and optical properties of nano and micro particles are studied by UV-visible spectroscopy, DLS, and SEM techniques. In this work, by microsecond pulses of Nd:YAG and using measuring devices such as Coherent power /energy meter, the appropriate optical table, the related experiments are implemented....
Critical temperature evaluation of moment frames by means of plastic analysis theory and genetic algorithm
, Article Iranian Journal of Science and Technology - Transactions of Civil Engineering ; 2021 ; 22286160 (ISSN) ; Saedi Daryan, A ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
Nowadays, deliberate or unwanted fire incidents have created much attention to the behavior of structures against these types of events. Since the properties of structural members are influenced by the increase in the temperature of the members, it is more difficult to predict the general and local behavior of the structures during the fire. In this research, a method has been proposed to calculate the critical temperature in two-dimensional structures at its collapse with desirable accuracy. In this process, the upper-bound theory of plastic analysis is used. The plastic analysis is performed by applying the initial fire scenario to the structure, and its collapse load factor with the...
Critical temperature evaluation of moment frames by means of plastic analysis theory and genetic algorithm
, Article Iranian Journal of Science and Technology - Transactions of Civil Engineering ; Volume 46, Issue 2 , 2022 , Pages 843-856 ; 22286160 (ISSN) ; Saedi Daryan, A ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Nowadays, deliberate or unwanted fire incidents have created much attention to the behavior of structures against these types of events. Since the properties of structural members are influenced by the increase in the temperature of the members, it is more difficult to predict the general and local behavior of the structures during the fire. In this research, a method has been proposed to calculate the critical temperature in two-dimensional structures at its collapse with desirable accuracy. In this process, the upper-bound theory of plastic analysis is used. The plastic analysis is performed by applying the initial fire scenario to the structure, and its collapse load factor with the...
Enhancement of the MAC Layer of Mobile Broadband Wireless Access Network
, M.Sc. Thesis Sharif University of Technology ; Ajorloo, Hossein (Supervisor)
Abstract
Mobile Broadband Wireless Access technologies provide mobile users with broadband services, for example music downloading, online games and etc. IEEE 802.20 standard is one of the Mobile Broadband Wireless Access technologies , which has been published to support mobile users with high vehicular speed up to 250(km/h). The issue studied in this research is enhancement of MAC layer in IEEE 802.20 standard.
By having this intention in mind we firstly developed a simulator for IEEE 802.20 MAC layer implementation , then we tried implementing 3 different approaches for connecting mobile users to a new network in order to analyze their performance. Then we provided a method for decreasing...
By having this intention in mind we firstly developed a simulator for IEEE 802.20 MAC layer implementation , then we tried implementing 3 different approaches for connecting mobile users to a new network in order to analyze their performance. Then we provided a method for decreasing...
Design and Implementation of Ka band Low Noise Amplifiers and Limiters
, M.Sc. Thesis Sharif University of Technology ; Medi, Ali (Supervisor)
Abstract
Todays the use of microwave integrated circuits for military and commercial applications has gained much attention, especially with the advent of monolithic microwave integrated circuits, which provide the possibility of fabrication of amplifiers in large number, sufficient accuracy an affordable price.GaAs pHEMT process, because of good characteristics for noise and power in high frequencies, is a good choice for microwave and millimeter wave integrated circuits. A low noise amplifier is a key block in the receiver and, its noise figure and gain directly affects the sensitivity and dynamic range of the receiver. Hence, a low noise amplifier with low NF, high gain, good return loss, low...
Integrated Safe Design of Industrial Processes under Uncertainty
,
M.Sc. Thesis
Sharif University of Technology
;
Rashtchian, Davood
(Supervisor)
;
Sharifzadeh, Monireh
(Supervisor)
Abstract
Chemical industries are associated with hazardous chemicals and extreme operating conditions. Unsafe events can incur dramatic costs in terms of the loss of life, financial penalties and damages to the environment. Therefore, design of industrial processes which can be operated safely over a wide range of operating conditions is vital. Nevertheless, operation of industrial processes is a strong function of their design. If the process is initially poorly designed, ensuring its safe operation, if not impossible, would require costly modifications at the operational phases. This observation is due to the fact that process design decisions (e.g. design of process equipment) often have a...
The effect of geometry on structural behavior of buildings with steel plate shear wall system subjected to blast loading
, Article International Journal of Steel Structures ; Volume 21, Issue 2 , 2021 , Pages 650-665 ; 15982351 (ISSN) ; Moghaddam, H ; Saedi Daryan, A ; Sharif University of Technology
Korean Society of Steel Construction
2021
Abstract
Many important public buildings have suffered significant damages due to terrorist attacks in the last few decades. This paper investigates the behavior of structures with steel plate shear wall lateral load resisting system under various blast loadings. A number of twenty steel frames with different heights and widths subjected to four different blast scenarios are modeled and analyzed in opensees software. The results showed that structures with steel plate shear wall systems subjected to blast loading have better behavior in high-rise structures than in low-rise structures in terms of drift and ductility ratio. The steel plate shear wall system exhibited shear-dominated,...
Estimation of Genetically Significant Dose to the Iranian Population from Diagnostic Radiology Procedures
, M.Sc. Thesis Sharif University of Technology ; Sohrabpour, Mostafa (Supervisor) ; Sharifzadeh, Monireh (Co-Advisor)
Abstract
Genetic significant dose to the Iranian population from diagnostic radiology procedures has been measured. A survey of 26500 radiology patients has radiological tests, age and sex distribution. A second survey has produced the radiological operational parameters, including kV, mAs, FTD, field size, filtration, film number & body orientation. Statistical demographic data have been obtained and from which child expectancy number have been calculated. A Rando phantom has been used for dosimetry phase of the gonad doses using TLD. Combining all of the above data a new GSD of 10.5 mrem/year has been calculated which is 14% higher than the previous number measured in 1980
Peer-to-Peer energy sharing among smart energy hubs in an integrated heat-electricity network
, Article Electric Power Systems Research ; Volume 206 , 2022 ; 03787796 (ISSN) ; Sheikhi, A ; Ashouri Zadeh, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
By increasing the penetration level of the combined heat and power systems and demand response programs between energy consumers in the distribution network, the interaction between electricity and the natural gas network becomes more complicated. This paper proposes a peer-to-peer (P2P) energy sharing scheme for energy trading among Smart Energy Hubs (S.E. Hubs) which can trade both electrical and thermal energy with each other to reduce their cost and, reduce their dependency to gas and electricity utility companies. A two-stage energy strategy is presented. In the first stage, the S.E. Hubs total social cost is reduced by finding the optimal energy sharing profiles. And, in the second...
Truss Section, Topology and Shape Optimization Considering Uncertainties
, M.Sc. Thesis Sharif University of Technology ; Kazemi, Mohammad Taghi (Supervisor)
Abstract
Optimization and uncertainty are two main issues in the structure design. In engineering problems and specially the structure, loads are among those issues witch we cannot be commented definitively. The uncertainty also shows itself in material properties and structural shapes. Design optimization is inevitable in order to use resources effectively. In the past, structural design was based on experience and engineering judgment, which was conservative and sometimes structure weight was very high. But today, thanks to computers, high-volume calculations would not be out of reach. With considering uncertainty, we can have prosper sight toward constraints by maintaining proper distance from...
Designing a Loadcell for a Walker to Measure Upper Extremities’ Forces
, M.Sc. Thesis Sharif University of Technology ; Zohoor, Hassan (Supervisor)
Abstract
In this project, two bidirectional loadcell are designed and fabricated to be installed on a walker. Then upper extremities’ forces and moments have been obtained. Results can be used for rehabilitation purposes in Spinal Cord Injuries and Cerebral Palsy cases. The method used in this project is as follows: First, since the commercial multidirectional loadcells are too expensive, the loadcell (and an appropriate electronic board) are fabricated. Ultimately, a complete gait analysis by means of VICON motion analysis and using inverse dynamic method has been held to measure upper extremities’ forces and moments in the wrist, elbow and shoulder. The results for a person with Spinal Cord Injury...
An Efficient Hardware Trojan Detector Using On-chip Ring Oscillator
, M.Sc. Thesis Sharif University of Technology ; Hesabi, Shahin (Supervisor)
Abstract
Nowadays integrated circuits are extremely vulnerable to hardware trojans (HT). Hardware trojans can be injected into the ICs in design or fabricate phase, and damage system’s functionality or security. In this thesis, we first describe hardware trojan definition, classification and types of HTs, negative effects, detection ways and analysis of them. Then we propose a new solution in order to solve the negative points of previous methods
Experimental Investigation of Microjet Engine Anomaly Detection Based on ANN Data Clustering Analysis
, M.Sc. Thesis Sharif University of Technology ; Saghafi, Fariborz (Supervisor)
Abstract
In this study, the possibility of detecting known and unknown anomalies in a micro jet engine is evaluated. the proposed method is neural network and clustering analysis. The process consists of two main parts, first part is experimental abnormal behavior simulation and second part is validation of proposed detection method. In the first part a micro jet engine (Olympuse HP) were used and we created pre-designed errors in engine normal behavior to record significant changes in its performance. Recorded outputs consist of six different variables: RPM, Exhaust gas temperature, Throttle command, Fuel pump voltage, Thrust and Fuel weight. In the second part, for analyzing data, we used...
The Role of Safety Attitudes and Attitudes Toward Vehicle in Urban Crashes
, M.Sc. Thesis Sharif University of Technology ; Kermanshah, Mohammad (Supervisor)
Abstract
Nearly 1.2 million people die in road crashes each year, and as many as 50 million are injured in the world. In Iran, approximately 800 thousand crashes occur annually killing up to 43 people per day. Given that over 90% of accidents are related to human factors, using models that incorporate driver’s attitudes and behavior can be highly predictive of crashes. The main objective of the current research is to examine the impact of drivers’ attitudes on road crashes along with other factors such as socio-demographic characteristics and vehicle type. This study uses data from a self-completed questionnaire among a representative sample of Iranian drivers living in Tehran. The Questionnaire...
Feasibility Study of Rapid Estimation of SF Parameter of Cells Using the Monte Carlo Simulation of Carbon Therapy in Combination with Cascade Feed-forward Neural Network (CFNN) by Bayesian Regularization Learning Algorithm
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor)
Abstract
Our main goal in this project is to calculate the cell survival fraction (SF) in unhealthy tissue after carbon ion beams are emitted and hit the target tissue. At present, in the stages of carbon therapy, it usually takes a long time to make the necessary calculations for that particular person, and this makes the treatment process progress slowly, but in this project, we intend to address this problem with Eliminating the use of neural network. The main reason is the use of carbon ions to increase efficiency in the treatment of tumors and deep cancerous tissues. To do this project, we first convert the carbon ion energy to the dose absorbed at the desired point. For this phase of the...
Effects of Microstructure and Salinity Concentration on Hydraulic Conductivity of Silty Clay Soils
, M.Sc. Thesis Sharif University of Technology ; Sadeghi, Hamed (Supervisor)
Abstract
Various contaminants and their leachate, when they penetrate into the soil, cause changes in soil microstructure, this change in microstructure leads to changes in soil permeability and volume. In this study, first, the effects of soil microstructure change on the hydraulic conductivity of saturated soil were investigated using the change in initial saturation degree during compaction for compacted samples and the change in sample construction in reconstituted samples. Also, the simultaneous effect of changing the initial microstructure and salt solution on the hydraulic conductivity of saturated silty clay soils using a three-axial permeability device with the ability to measure volume...
Size and layout optimum design of frames with steel plate shear walls by metaheuristic optimization algorithms
, Article Structures ; Volume 48 , 2023 , Pages 657-668 ; 23520124 (ISSN) ; Salari, M ; Palizi, S ; Farhoudi, N ; Sharif University of Technology
Elsevier Ltd
2023
Abstract
Optimization of a structure refers to a design procedure that results in the most economical structure in terms of materials and sizing of sections. In structures with steel plate shear walls, finding the best layout of the walls in a frame is also of priority in designing a structure with the minimum weight. Finding the least weight of a structure while all design provisions according to codes and standards are satisfied is a challenging task that is hard to perform with the existing design methods. Metaheuristic optimization algorithms are robust computational tools used for solving complex problems, which are used widely in many engineering fields, especially structural engineering. This...
The ion streaming effect on weibel instability in the relativistic dense plasma
, Article Contributions to Plasma Physics ; Volume 57, Issue 8 , 2017 , Pages 351-356 ; 08631042 (ISSN) ; Mahdavi, M ; Sharif University of Technology
2017
Abstract
The Weibel instability plays an important role in stopping hot electrons and energy deposition mechanism in fast ignition of inertial fusion process. In this paper, the ion Weibel instability in counter propagating electron-ion plasmas is investigate. The obtained results show that the growth rate of Weibel instability will be decreased about 40% with the anisotropy velocity as vxe = 2vze = 20; the ion density ratio, b = n0i1/n0i2, and density gradient, are increasing 50 and 90% respectively. The ion streaming in density gradient of dense plasma leads to increasing the Weibel instability growth rate and its amplification through ion streaming in the large wavenumber. The maximum unstable...
Numerical Solution of Hypersonic Axisymmetric Flows Including Real Gas Effects Using Compact Finite-Difference Scheme
, M.Sc. Thesis Sharif University of Technology ; Hejranfar, Kazem (Supervisor)
Abstract
The numerical solution of the parabolized Navier-Stokes (PNS) equations for accurate computation of hypersonic axisymmetric flowfield with real gas effects is obtained by using the fourth-order compact finite-difference method. The PNS equations in the general curvilinear coordinates are solved by using the implicit finite-difference algorithm of Beam and Warming type with a high-order compact accuracy. A shock fitting procedure is utilized in the compact PNS scheme to obtain accurate solutions in the vicinity of the shock. To stabilize the numerical solution, numerical dissipation term and filters are used. The main advantage of the present formulation is that the basic flow variables...
The numerical solution of the parabolized Navier-Stokes (PNS) equations for accurate computation of hypersonic axisymmetric flowfield with real gas effects is obtained by using the fourth-order compact finite-difference method. The PNS equations in the general curvilinear coordinates are solved by using the implicit finite-difference algorithm of Beam and Warming type with a high-order compact accuracy. A shock fitting procedure is utilized in the compact PNS scheme to obtain accurate solutions in the vicinity of the shock. To stabilize the numerical solution, numerical dissipation term and filters are used. The main advantage of the present formulation is that the basic flow variables...
Analysis and Modeling of User Behavior over Social Media
, Ph.D. Dissertation Sharif University of Technology ; Rabiee, Hamid Reza (Supervisor)
Abstract
Nowadays many of us spend a big part of our daily times on social media.One of the most important research problems in social media analysis is how to engage users. The trace of user activity over these websites is a valuable resource for user understanding and engagement, but this data is very huge and unstructured. An approach to deal with this problem is user behavior modeling. In this process, first a behavioral model is considered for users, then using the activity data and the behavioral model, some parameters are learned. Finally, using the learned parameters, a user profile is constructed for each user. This profile can be used for user engagement and many other applications....