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monte-carlo-methods
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Determination of Parabolic Trough Solar Collector Efficiency Using Al2O3/Synthetic Oil Nanofluid: A Comprehensive Numerical Study with The Effect of Wind Velocity
, Ph.D. Dissertation Sharif University of Technology ; Shamloo, Amir (Supervisor) ; Kazemzadeh Hannani, Siamak (Supervisor)
Abstract
Due to significant reduction in fossil fuel sources; several researches have been conducted recently to explore modern sources of renewable energy. One of the major fields in the category of renewable energy harnessing devices is parabolic trough solar collectors (PTC). Several parameters have effect on the overall efficiency of the PTC’s.As the effect of these parameters is coupled to each other, a comprehensive investigation is necessary.In the present study a numerical analysis is performed to examine the efficiency of PTCs via variation of several governing parameters (e.g. wind velocity magnitude, nanoparticles volume fraction, inlet temperature and reflector’s orientation). A detailed...
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...
Modeling and Optimization of Respiratory-Gated Proton Therapy for Breast Cancer Using Monte Carlo Simulation
, Ph.D. Dissertation Sharif University of Technology ; Vosoughi, Naser (Supervisor) ; Mahani, Hojjatollah (Supervisor)
Abstract
Breast cancer is the most common cancer among women and has a growing rate. A combination of the proton beam and Accelerated partial breast irradiation (APBI) strategy can be effective in the case of the respiratory-induced target motion for breast cancer treatment. Due to the proximity of breast tissue to the two critical organ at risks (OARs) such as the lungs and heart, breast cancer proton therapy requires special considerations. The use of proton therapy with respiratory considerations (respiratory-gated), although a powerful way to control the mobile targets in breast cancer proton therapy, but needs to be optimized and improved as much as efficiency.The simulation and modeling of the...
Accurate Generation of Scintillator Detector Energy Spectrum by Monte Carlo Method for Gamma-Ray Spectrum Analysis Using whole Spectrum Data
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor)
Abstract
Generating the experimental spectrum for all gamma-ray elements is difficult and practically impossible in some industrial applications. Furthermore, in many applications such as neutron activation, it is not possible to obtain an experimental spectrum for a single isotope on account of the fact that the gamma-ray spectrum obtained from neutron activation is derived from the gamma-rays of various elements in a sample. Therefore, using computational techniques like Monte Carlo method for calculating the detector response functions seems an appropriate solution. The detector response functions for 3''×3'' NaI detectors have been simulated using MCNPX 2.7 code and Ptrac card in this project....
Design of Sustainable Electronic Waste Management System
, M.Sc. Thesis Sharif University of Technology ; Avami, Akram (Supervisor)
Abstract
The growing amounts of generation of electronic wastes (e-waste) and their increasing environmental impacts require a special optimal waste management strategy. Many different methods have been developed to managing e-waste. To make the best choices according to the conditions of each system, having an adequate knowledge of all methods and comparing them is the most important point. This research aims to design a system for managing e-waste by selecting mobile phones as an example of electronic waste and find the optimal condition of the system to increase economic benefits and reduce environmental impact. Recycling and landfill are selected as the main methods in this project. Four lines...
A Monte Carlo Method for Neutron Noise Calculation in the Frequency Domain
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor)
Abstract
Neutron noise equations, which are obtained by assuming small perturbations of macroscopic cross sections around a steady-state neutron field and by subsequently taking the Fourier transform in the frequency domain, have been usually solved by analytical techniques or by resorting to diffusion theory, but in this thesis, in order to increase of accuracy of neutron noise calculation, has been used transport approximation for neutron noise calculation and the Monte Carlo method has been used to solve transport equation of the neutron noise in the frequency domain. Since the transport equation of the neutron noise is a complex equation, a new Monte Carlo technique for treating complex-valued...
Use of Data Assimilation Methods for Multiphase Flow in Porous Media
, M.Sc. Thesis Sharif University of Technology ; Rajabi Ghahnavieh, Abbas (Supervisor) ; Bazargan, Hamid (Co-Supervisor)
Abstract
The importance of optimizing the extraction process of available resources increases each day due to the increasing energy consumption and the lack of energy resources. Oil and gas are one of the most important sources of energy. Although existing oil and gas resources are thought to be sufficient to meet the growing energy demand for the next few decades, given the non-renewable nature of these resources and the growing demand for oil and gas, it will become much harder to meet the future energy demand. Many existing oil fields are now in the process of maturing, and the discovery of large new oil fields is rare. As a result, new technologies must be used in the future to meet this demand,...
Range Verification and Dose Evaluation in Proton Therapy by Using Monte Carlo Method
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor)
Abstract
In this study, the emission and detection of secondary particles such as gamma and neutron along the beam path was investigated to evaluate proton range during treatment. Simulations and detections were performed by Geant4 toolkit that was developed base on Monte Carlo method. First, a mono-energetic proton beams irradiated a homogeneous water phantom. Then the factors influencing the accuracy of beam range estimation have been investigated and finally proton beam range was evaluated by simulation the human eye phantom. According to the results, the accuracy of range verification by prompt gamma is very high, about 1 mm. In phantoms with more oxygen in their composition, the percentage of...
A 3-D and Time Dependent Software for Particles Tracking Base on Monte Carlo Method
, Ph.D. Dissertation Sharif University of Technology ; Salehi, Ali Akbar (Supervisor) ; Vosoughi, Naser (Co-Supervisor)
Abstract
A highly reliable tool for transient simulation is vital in the safety analysis of a nuclear reactor. Despite this fact most tools still use diffusion theory and point-kinetics that involve many approximations such as discretization in space, energy, angle and time. However, Monte Carlo method inherently overcomes these restrictions and provides an appropriate foundation to accurately calculate the parameters of a reactor. For this reason, in this thesis, a dynamic Monte Carlo code named MCSP (Monte Carlo dynamic Simulation of Particles tracking) is developed for both the steady state and time-dependent simulation of particle (neutrons, photons and electrons) tracking in an arbitrary 3D...
Modeling of Optimal Design of Solar Collector in Multi-energy Hybrid Systems based on Minimum Exergy Destruction
, M.Sc. Thesis Sharif University of Technology ; Saboohi, Yadollah (Supervisor) ; Fathi, Amir Hossein (Co-Supervisor)
Abstract
Concentrated photovoltaic systems (CPVs) allow simultaneous production of electrical energy and high-temperature thermal energy. These systems consist of a concentrator for collecting solar rays onto the surface of the recipient cells. Moreover, these systems are always facing the sun using a sun tracker. The heat generated by these systems can be used in industrial processes, heating, cooling, and water desalinating. Given the concurrent generation of power and high-temperature heat, it is possible to achieve higher efficiency than that of conventional solar systems. Furthermore, the electrical efficiency is also higher than conventional systems due to the use of multi-junction solar cells...
Simulation of Intensity Modulated Radiation Therapy (IMRT) and Assessment of the Time Parameter
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor) ; Mahdavi, Rabi (Supervisor) ; Robat Jazi, Mostafa (Co-Advisor)
Abstract
It is necessary to evaluate dosimetry accuracy in the framework of advanced methods for radiation therapy such as Intensity Modulated Radiation Therapy (IMRT) to ensure reliability of a proposed treatment. The ability of the Monte Carlo codes to model linear accelerator (LINAC) and to calculate the exact dose distribution in clinical radiation therapy is one of the reasons to use such codes. The purpose of this project is to validate a treatment planning system with BEAMnrc and DOSXYZnrc Monte Carlo codes. In this study, the dose distribution obtained from DOSXYZnrc in considered to be thr main criterion with which the dose distribution obtained from treatment planning system is assessed and...
Accelerating MCNP using the Adjoint Flux
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor) ; Ayyoubzadeh, Mohsen (Co-Advisor)
Abstract
Nuclear engineering simulation requires computer codes which are capable of particle transportation and presenting valid answers. The Monte Carlo method is one of the particle transportation methods and the MCNP code is also a common and efficient code using Monte Carlo method. We usually come across statistical errors in Monte Carlo simulation for reducing which a number of methods have been presented which are called variance reduction methods. In simulating deep penetrating problems, analog Monte Carlo method is weak which leads to considerable error. The chosen variance reduction method for this study is the one which uses adjoint flux. In this study, a 3D deterministic transport code...
Optimum Design, Simulation and Performance Evaluation of Animal PET System
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor) ; Ay, Mohammad Reza (Supervisor)
Abstract
PET systems are a kind of functional nuclear medicine instruments. In this systems a radionuclide is injected to body and output gamma rays is detected. PET can recognise cancer 10 times earlier than other imaging systems such as CT scan also the treatment plan can followed by PET. In the last two decades, the use of small-animal models in the field of biomedical research for studying disease have accelerated and dedicated small animal PET systems have started playing their role as strong imaging modalities in investigating cellular and molecular processes in live animals. Animal and human PETs have similar technology just human PET is bigger, so at this project, animal PET is designed for...
Design of Multi-purpose Gamma Irradiator System Based on Combined Monte Carlo Geant4 and GPU Hardware
, M.Sc. Thesis Sharif University of Technology ; Sohrabpour, Mostafa (Supervisor)
Abstract
Gamma irradiation systems are used extensively in the industry in order to sterilize medical devices, disinfect hygienic materials or increase the shelf life of agricultural produce. The method of gamma irradiation is superior to the older methods of heat or chemical treatment because it is by far a simpler operation. In this method only a single parameter of time is controlled whereas in the other mentioned methods five or six different parameters need to be controlled. The design of irradiation systems including the size, location of products and arrangement of source rack pencils. In order to optimize the design it is needed to study the products dose distribution in a wide range of...
Statistical Modeling and Analysis of Novel Linear and Nonlinear Receivers for Ultrashort Light Pulse Detection
, M.Sc. Thesis Sharif University of Technology ; Salehi, Javad (Supervisor)
Abstract
Utilizing ultrashort light pulses in optical communication systems can enhance the data rate or throughput in multiple access telecommunication systems. One of the most important challenges in ultrashort light pulse communication systems is the detection of such pulses among various types of noise in the receiver with conventional band-limited photodetectors which is proved to degrade the detection performance considerably. To overcome the aforementioned obstacle, contriving nonlinear optical preprocessors prior to the photodetector at the receiver is suggested. This preprocessor can increase the discrimination between ultrashort light pulse with high peak power and the noise with average...
Development of the Electron and Photon Transport Code for Dose Calculations on GPU and Benchmarking with EGSnrc Simulation for Radiotherapy
, M.Sc. Thesis Sharif University of Technology ; Sohrabpour, Mostafa (Supervisor)
Abstract
Almost half of all cancer patients receive radiation therapy as main or part of the treatment process. Before performing radiation therapy, first it is necessary to determine the patient’s treatment plan and estimate the outcome of it based on the dose distribution. The quality of treatment is dependent on the accuracy of dosimetry calculations that lies in Monte Carlo algorithms. Unfortunately, most of the computation time is long and not suitable for clinical applications. On the other hand, a real treatment planning will be possible if all aspects of radiation therapy should be considered. The radiation source that is obtained from a medical linear accelerator head is one of these...
Neutronics Calculations of Prismatic High-temperature Gas Cooled Reactor by Deterministic Method Using DONJON and DRAGON Codes and Comparison with Results of Probabilistic Methods (Monte Carlo).
,
M.Sc. Thesis
Sharif University of Technology
;
Ghofrani, Mohammad Bagher
(Supervisor)
Abstract
HTGRs are considered as 4th generation reactors which have prominent characteristics such as inherent safety, lower safety costs, High efficiency and high temperature applications. the most important challenges in developing these reactors is providing appropriate codes in design, simulating their performance and analysis of them. In this thesis, a japanese prismatic HTTR reactor has been selected as a reference reactor and the neurotic’s calculations implementation studied at cold zero power (CZP) and hot full power (HFP) states using DRAGON cell calculation codes and DONJON core computations. At CZP state, One group and two group radial & axial flux distribution, control rod critical...
The Effect of GPU for Radiation Transport of Photons and Electrons for dose Calculation
, M.Sc. Thesis Sharif University of Technology ; Sohrabpour, Mostafa (Supervisor) ; Vosoughi, Naser (Co-Advisor)
Abstract
In radiotherapy, dose calculation is one of the most important stages that should be carefully done for patient treatment planning. Dose calculation methods have been developed from early dose algorithms that used analytical methods to relatively recent high precision monte carlo methods.Monte carlo methods while very accurate in dose estimations usually suffer from long computation time. In the recent time the emphasis for reduction of the computation time has been focused on software techniques as well as on hardware technology development. One example of hardware development has been graphic processing unit (GPU) which was introduced in 2006 by the Nvidia to accelerate the processing and...
Exact Simulation of Varian Clinac 2100C/D with Use of Phase Space file and Representation of Appropriate Source Model for Clinical Applications
, Ph.D. Dissertation Sharif University of Technology ; Sohrabpour, Mostafa (Supervisor) ; Rabi Mahdavi, Saeed (Co-Advisor)
Abstract
MC Simulation is considered to be one of the most accurate methods for transport of radiation in various media. Computational speed is the limiting factor to apply the MC method in clinical settings. One of the methods to increase the speed in MC simulations is the use of phase space file (PSF). PSF is generated by transporting the particles through the linear accelerator head. The characteristics of these particles crossing a reference plane are stored in the PSF file. The PSF can be used in subsequent simulations as a radiation source. The use of PSF is effective but has a drawback of having latent variance. Latent variance is a problem inherent in using phase space files. Latent variance...
Calculation of Pulse Height Distribution by Deterministic and Monte Carlo Methods
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor)
Abstract
Radiation detection techniques have important applications including prompt gamma neutron activation analysis (PGNAA), radiotherapy dose measurement, medical imaging and homeland security. Pulse height distribution is also a useful parameter in Radionuclide identification. Gamma ray spectroscopy analysis is a common technique in measuring of radiation field to identify the radioactive source.
Probabilistic methods are commonly used for numerical simulation of Pulse height distribution. In Monte Carlo methods, each history is individually tracked and details of interactions are available. Using the Monte Carlo methods for calculation of pulse height distribution leads to more real...
Probabilistic methods are commonly used for numerical simulation of Pulse height distribution. In Monte Carlo methods, each history is individually tracked and details of interactions are available. Using the Monte Carlo methods for calculation of pulse height distribution leads to more real...