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    Punishment Normative Systems

    , M.Sc. Thesis Sharif University of Technology Feghhi, Saman (Author) ; Ramezanian, Rasoul (Supervisor)
    Abstract
    In real life, we can not always expect agents and authorities to have the same desires. Also when it comes to conflicts, agents always tend to break the authorities’ norms to follow their own strategies. Hence we can not expect strict norms to model an actual real life situation.In this article we introduce punishment normative systems, based on multi-agent Marokov chain processes (MMDPs). We try to extend the punishment idea to be also applicable on long-run and infinite strategies. We consider a version of the multi-agent model that is widely used in different situations and then provide an algorithm to find a fair normative system that distributes obligations equally on the agents, while... 

    Computational Design of Novel Medicines as Inhibitors in Case of Cancer and Autoimmune Disease Treatment Based on Amino Acid and Sugar

    , M.Sc. Thesis Sharif University of Technology Feghhi, Razieh (Author) ; Fattahi, Alireza (Supervisor)
    Abstract
    SHP2 has been reported as a critical non-receptor phosphatase enzyme that plays crucial roles in numerous disorders like cancer. The previous studies on this enzyme showed that inhibiting the action of the enzyme comes as a way of controlling enzyme activity. SHP099 was discovered as an Allosteric inhibitor of the enzyme with the most inhibitory effect among all of the studied compounds. In this study we aimed to design novel dipeptide-and sugar-based inhibitors for the allosteric binding site of this enzyme with in-silico studies including docking, molecular dynamic simulation, and free binding energy analysis. Our novel designed drugs possess enough binding properties, low toxicity, and... 

    Characteristics of Defensive Layers for High Value Targets Based on Game Theory

    , M.Sc. Thesis Sharif University of Technology Feghhi, Naeem (Author) ; Malaek, Mohammad Baqer (Supervisor)
    Abstract
    In this work, we investigate how the so called “Game Theory” could be applied to study the effectiveness of the defensive layers of a high-value target. A High-value target is usually protected by different defensive layers; the characteristics of which very well depends on the attacker capabilities. Here, we show “Game Theory” can effectively provide new alternatives to increase the chance of survival for the “High Value” target by increasing the risks for the attacker. In this work, we assume any attack is not executed in one stage and defensive layers could be designed to increase the duration of the game. We also assume the game ends as soon as there are no more weapons d to protect the... 

    Power allocation in the energy harvesting full-duplex Gaussian relay channels

    , Article International Journal of Communication Systems ; Volume 30, Issue 2 , 2017 ; 10745351 (ISSN) Feghhi, M. M ; Mirmohseni, M ; Abbasfar, A ; Sharif University of Technology
    John Wiley and Sons Ltd  2017
    Abstract
    In this paper, we propose a general model to study the full-duplex non-coherent (NC) decode-and-forward Gaussian relay channel (RC) with energy harvesting (EH) nodes, called NC-EH-RC, in three cases: (i) no energy transfer (ET), (ii) one-way ET from the source (S) to the relay (R), and (iii) two-way ET. We consider the problem of optimal power allocation in NC-EH-RC in order to maximize the total transmitted bits from S to the destination in a given time duration. General stochastic energy arrivals at S and R with known EH times and values are assumed. In NC-EH-RC with no ET, the complicated min-max optimization form along with its constraints make the problem intractable. It is shown that... 

    Low complexity resource allocation in the relay channels with energy harvesting transmitters

    , Article Ad Hoc Networks ; Volume 77 , 2018 , Pages 108-118 ; 15708705 (ISSN) Mohassel Feghhi, M ; Abbasfar, A ; Mirmohseni, M ; Sharif University of Technology
    Elsevier B.V  2018
    Abstract
    Energy Harvesting (EH) is a novel technique to prolong the lifetime of the wireless Ad-hoc and sensor networks with replenishable nodes. In this sense, it has emerged as a promising technique for Green Communications. On the other hand, cooperative communication with the help of relay nodes improves the performance of wireless communication networks. In this paper, we investigate the cooperation in EH nodes. We consider the optimal power and rate allocation in the full-duplex Gaussian relay channel in which source and relay can harvest energy from their environments. In our model, the energy arrivals at the source and the relay are general stochastic processes with known EH times and amounts... 

    The formation and dissociation energy of vacancies in cementite: A first-principles study

    , Article Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms ; Volume 502 , 2021 , Pages 157-163 ; 0168583X (ISSN) Mehrdad Zamzamian, S ; Amirhossein Feghhi, S ; Samadfam, M ; Sharif University of Technology
    Elsevier B.V  2021
    Abstract
    Because of the possibility of various types of vacancies in cementite due to its crystalline structure, the focus of this paper was only on vacancies. In this regard, the formation energies of single, two, three and four vacancies of over than 120 different cases were calculated using first-principles method. For the case of single vacancy, the results were in three values of ~1.63, 1.39 and 0.78 eV according to iron vacancies at general positions, iron vacancies located on mirror planes and carbon vacancies in the interstitial positions, respectively. The results for the case of two, three and four vacancies were between from 2.10 to 3.34 eV, from 3.92 to 5.10 eV and from 4.77 to 6.33 eV,... 

    Bandgap tailoring and enhancing the aromatization in cysteine-based carbon dots

    , Article Journal of Colloid and Interface Science ; Volume 651 , 2023 , Pages 36-46 ; 00219797 (ISSN) Feghhi, F ; Minagar, A ; Madaah Hosseini, H. R ; Sharif University of Technology
    Academic Press Inc  2023
    Abstract
    Cysteine, as a non-aromatic precursor, was used to produce Nitrogen (N) and Sulfur (S) sources for preparing N, S-doped carbon dots (CDs) with tunable luminescence emission. Despite the tremendous investigations, the photoluminescence (PL) mechanism of CDs is still unclear due to its complex core–shell structure, variety of surface functional groups, and structure dependency. This study focuses on controlling aromatization and graphitization processes during the hydrothermal synthesis on CDs by using Citric Acid (CA) and Ammonium persulfate. Detailed characterizations by FTIR spectroscopy, XPS, and HR-TEM are provided to suggest both chemical and bandgap structures. Results reveal that the... 

    Investigating Process Factors on Red-shift of Photoluminescence of Carbon Dots

    , M.Sc. Thesis Sharif University of Technology Feghhi, Fazeleh (Author) ; Madah Hosseini, Hamid Reza (Supervisor)
    Abstract
    In recent years, studies in luminescent carbon dots are overgrowing, the prominent features of carbon quantum dots include cheap and straightforward synthesis, excellent biocompatibility, and adjustable optical properties. However, the widespread use of carbon dots in biomedical diagnostics, photoluminescence, and photocatalysis has been limited due to a lack of emission and excitation in the red or near-infrared region.. However, the widespread use of carbon dots in biomedical diagnostics, photoluminescence, and photocatalysis has been limited due to a lack of emission and excitation in the red or near-infrared region. This research tried to produce carbon dots with redshift in emission... 

    Short Term and Long Term Analysis of Radiation Damage in Carbon Based Steels with Emphasis on Reactor Pressure Vessel

    , Ph.D. Dissertation Sharif University of Technology Zamzamian, Mehrdad (Author) ; Samadfam, Mohammad (Supervisor) ; Feghhi, Amir Hossein (Supervisor)
    Abstract
    Steels as structural materials of pressure vessels of nuclear reactors, in addition to high temperatures and pressures, are exposed to ionizing radiation such as neutrons. The primary effects of damage caused by exposing these solids to radiation are the displacement of atoms from their equilibrium positions and the formation of point defects and damage clusters caused by damage accumulation due to displacement cascades produced by transmitting the energy of the incident particle to an atom by interactions such as elastic and inelastic scatterings neutrons with the nucleus. These microstructural changes cause large structural defects such as swelling, cracking, cracking, creep, reducing... 

    Atomistic simulation of the effect of carbon content and carbon-rich region on irradiation response of α-Fe on picosecond timescale

    , Article Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms ; Volume 443 , 2019 , Pages 70-78 ; 0168583X (ISSN) Zamzamian, S. M ; Samadfam, M ; Feghhi, S. A ; Arjhangmehr, A ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    α-Fe with low carbon content is a base material which is commonly used in manufacturing of Reactor Pressure Vessel (RPV) of commercial nuclear power plants. Carbon is generally diffused to α-Fe matrix to improve some of its mechanical properties. The presence of carbon may alter the irradiation response of the steel. In the current study, using molecular dynamics simulations, we have investigated the influence of carbon (∼in either dispersed form or carbon-rich region as chain) in the primary damage states of α-Fe low carbon steels. It is found that carbons in dispersed form have no significant effect on the self-interstitial atoms (SIAs) in α-Fe. While, carbon-rich (C-rich as... 

    Feasibility Study and Conceptual Design of A Radioisotope Thermoelectric Generator

    , M.Sc. Thesis Sharif University of Technology Amirnasab, Mohammad (Author) ; Vosoughi, Naser (Supervisor) ; Feghhi, Amir Hosain (Supervisor)
    Abstract
    Radioisotope thermoelectric generator (RTG) is a kind of nuclear batteries, in which thermal energy resulting from the discharge of charged particles decayed of radioisotope, using thermoelectric arrays, can be converted to electrical energy. In this study, the different kinds of RTGs introduced and applications of them have been expressed. All types of radioisotopes used in RTGs have been reviewed and the most suitable of them in terms of maximum thermal power density and minimum dose rate have been selected. All types of thermoelectrics used in RTGs have been reviewed and the most suitable of them in terms of the range of temperature and maximum efficiency have been selected.
    In this... 

    Determining of the optimized dimensions of the Marinelli beaker containing source with inhomogeneous emission rate by using genetic algorithm coupled with MCNP and determining distribution type by neural networks

    , Article Applied Radiation and Isotopes ; Volume 157 , 2020 Zamzamian, S. M ; Hosseini, S. A ; Feghhi, S. A ; Samadfam, M ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    In order to determine the activity of C137s in soil resulting from nuclear accidents or fallouts, the best choice is to use HPGe detectors due to their best energy resolutions. In this regard, in order to enhance the detection efficiency, the Marinelli beakers have been used to increase the radiation interaction with the sensitive volume of the detector. In previous works, to optimize the dimension of Marinelli beakers, the assumption was that the emission rate of the source is homogeneous in beaker volume. In the present study, to investigate the effect of the inhomogeneous emission rate of the source on the optimum dimensions of the beaker, in a simple case, the beaker was divided into two... 

    Numerical Hydrodynamics for Compact Stars

    , M.Sc. Thesis Sharif University of Technology Feghhi, Touhid (Author) ; Mansouri, Reza (Supervisor) ; Taghizadeh Firouzjaee, Javad (Supervisor)
    Abstract
    Compact Objects involve White Dwarfs,Neutron Stars and Black Holes which are formed from the gravitational collapse of main sequence stars after their nuclear fuel is finished.The special characteristic of all Compact Objects is that they are high density which requires a vast knowledge of nuclear physics with strong and weak interactions ,electromagnetic and numerical methods.we need general relativistic simulation of stars because the theories are simple and some are not in agreement with observations. studying of astro physical constraints on equation of state ,stability and cooling of Neutron Stars and pulsation of gravitational waves is needed nowadays. in first part of this thesis,we... 

    An investigation on the improvement of neutron radiography system of the tehran research reactor by using MCNPX simulations

    , Article Nuclear Engineering and Technology ; Volume 53, Issue 10 , 2021 , Pages 3413-3420 ; 17385733 (ISSN) Amini, M ; Zamzamian, M ; Fadaei, A. H ; Gharib, M ; Feghhi, A. H ; Sharif University of Technology
    Korean Nuclear Society  2021
    Abstract
    Applying the available neutron flux for medical and industrial purposes is the most important application of research reactors. The neutron radiography system is used for non-destructive testing (NDT) of materials so that it is one of the main applications of nuclear research reactors. One of these research reactors is the 5 MW pool-type light water research reactor of Tehran (TRR). This work aims to investigate on materials and location of the beam tube (BT) of the TRR radiography system to improve the index parameters of BT. Our results showed that a through-type BT with 20 cm thick carbon neutron filter, 1.2 cm and 9.4 cm of the diameter of inlet (D1) and output (D2) BT, respectively... 

    Development a Computer Program for Burn-Up Calculation Using Monte-Carlo Method

    , M.Sc. Thesis Sharif University of Technology Khaki Arani, Mehdi (Author) ; Ghofrani, Mohammad Bagher (Supervisor) ; Feghhi, Amir Hossein (Supervisor)
    Abstract
    Burnup calculations based on the Monte Carlo method have been developed in line with the improvements in computing technology. Nowadays, in the field of nuclear reactor physics, it is possible to perform burnup calculation in a detailed 3D geometry and continuous energy description by the Monte Carlo method. COMB is a fully automated code in DELPHI 7 that links the MCNP4C Monte Carlo transport code with the radioactive decay and burnup calculation code system, ORIGEN2.1. The principal function of COMB is first to transfer one-group cross sections and fluxes from MCNP4C to ORIGEN2.1, and then transfer the resulting material compositions (after irradiation and/or decay) from ORIGEN2.1 back to...