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Iran’s Air Quality Modeling Using CMAQ-WRF Coupled Model
, M.Sc. Thesis Sharif University of Technology ; Arhami, Mohammad (Supervisor)
Abstract
Industrialization has brought about air pollution which is one of the most important factors threatening human health. The most efficient method to improve air quality include preventing the emission of pollutants by making laws and regulations. In order to set appropriate regulations, there needs to be a correct understanding of the problem. The purpose of this research is to identify such factors and create a correct understnding of the problem in Iran by constructing a Model of Iranian air qulity. The model used in this research, CMAQ is one of the most comprehensive and state of the art models in transport of pollutnts and chemical reactions in the atmosphere. The inputs into CMAQ...
An Algorithm for Analyzing the Spatial Distribution of the Evolutionary Development Processes
, M.Sc. Thesis Sharif University of Technology ; Foroughmand-Araabi, Mohammad Hadi (Supervisor)
Abstract
Evolutionary processes are the process of change in one or more physical and heritable characteristics that result from the occurrence of genetic changes (beneficial, harmful, or neutral) over time, and ultimately from generation to generation, depending on natural selection. Cancer is a genetic disease that occurs as a result of an evolutionary process by the somatic cells and examining the spatial characteristics of cancer can help understanding it. It is also important to examine the spatial configuration of cells considering their access to limiting factors such as nutrients and adequate space. In addition, paying attention to the gene expression, individually and collectively, will help...
Thermoelastic fields of a functionally graded coated lnhomogeneity with sliding/perfect interlaces
, Article Journal of Applied Mechanics, Transactions ASME ; Volume 74, Issue 3 , 2007 , Pages 389-398 ; 00218936 (ISSN) ; Shodja, H. M ; Sharif University of Technology
2007
Abstract
The determination of the thermo-mechanical stress field in and around a spherical/ cylindrical inhomogeneity surrounded by a functionally graded (FG) coating, which in turn is embedded in an infinite medium, is of interest. The present work, in the frame work of Boussinesq/Papkovich-Neuber displacement potentials method, discovers the potential functions by which not only the relevant boundary value problems (BVPs) in the literature, but also the more complex problem of the coated inhomogeneities with FG coating and sliding interfaces can be treated in a unified manner. The thermo-elastic fields pertinent to the inhomogeneities with multiple homogeneous coatings and various combinations of...
Modelling Evaporation & Salinity Variation in Saline Lakes Using Spatial System Dynamics: The Case of Urmia Lake
,
Ph.D. Dissertation
Sharif University of Technology
;
Tajrishy, Masoud
(Supervisor)
Abstract
Evaporation is the most important water loss from terminal lakes which can influence the chemistry of lakes. In large lakes, the spatial distributions of meteorological and water quality variables affect the evaporation rates. Therefore, it is crucial to consider such variations in estimating evaporation rates from large lakes. This study aims at developing an evaporation estimation model for saline lakes considering salinity and spatial distribution of variables in/over the lakes and investigating the interaction between meteorological, hydrological and water quality variables in natural saline systems. To accomplish these objectives, first a distributed model was developed for estimating...
Gaussian theory for spatially distributed self-propelled particles
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 94, Issue 6 , 2016 ; 15393755 (ISSN) ; Schimansky Geier, L ; Ejtehadi, M. R ; Sharif University of Technology
American Physical Society
2016
Abstract
Obtaining a reduced description with particle and momentum flux densities outgoing from the microscopic equations of motion of the particles requires approximations. The usual method, we refer to as truncation method, is to zero Fourier modes of the orientation distribution starting from a given number. Here we propose another method to derive continuum equations for interacting self-propelled particles. The derivation is based on a Gaussian approximation (GA) of the distribution of the direction of particles. First, by means of simulation of the microscopic model, we justify that the distribution of individual directions fits well to a wrapped Gaussian distribution. Second, we numerically...
Quantitative determination of linear alkylbenzene sulfonate (LAS) concentration and simultaneous power generation in a microbial fuel cell-based biosensor
, Article Journal of Cleaner Production ; Volume 294 , 2021 ; 09596526 (ISSN) ; Vahabzadeh, F ; Mardanpour, M. M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Linear alkylbenzene sulfonate (LAS), one of the most widely used synthetic surfactants in laundry detergent industry, is considered a hazardous contaminant in wastewater. In the present study, a microbial fuel cell (MFC) based biosensor is developed to quantitively determine the LAS concentration in wastewater. To do so, the developed MFC is fed with LAS concentration of 60 mg l−1. Finally, a sustained biofilm is formed after almost 34 days and the highest open circuit potential of 425 mV is recorded. The maximum power and current densities of 75 mW m−3 and 663 mA m−3 are obtained, respectively; and the internal resistance of the MFC-based biosensor is calculated to be about 1 kΩ. After 98...
A modeling platform for landslide stability: A hydrological approach
, Article Water (Switzerland) ; Volume 11, Issue 10 , 2019 ; 20734441 (ISSN) ; Ataie Ashtiani, B ; Sharif University of Technology
MDPI AG
2019
Abstract
Landslide events are among natural hazards with many fatalities and financial losses. Studies demonstrate that natural factors such as rainfall and human activities such as deforestation are important causes of triggering a landslide. In this study, an integrated two-dimensional slope stability model, SSHV-2D, is developed that considers various aspects of hydrological effects and vegetation impacts on the stability of slopes. The rainfall infiltration and water uptake of roots change the water content of the unsaturated zone. The temporal and spatial distribution of water content is estimated in the hydrological unit of the developed model. The vegetation unit of the model considers...
Rock Type Connectivity Estimation Using Percolation Theory
, Article Mathematical Geosciences ; Vol. 45, issue. 3 , April , 2013 , p. 321-340 ; ISSN: 18748961 ; Masihi, M ; Pishvaie, M ; King, P. R ; Sharif University of Technology
Abstract
Complicated sedimentary processes control the spatial distribution of geological heterogeneities. This serves to make the nature of the fluid flow in the hydrocarbon reservoirs immensely complex. Proper modeling of these heterogeneities and evaluation of their connectivity are crucial and affects all aspects of fluid flow. Since the natural variability of heterogeneity occurs in a myriad of length scales, accurate modeling of the rock type connectivity requires a very fine scheme, which is computationally very expensive. Hence, this makes other alternative methods such as the percolation approach attractive and necessary. The percolation approach considers the hypothesis that a reservoir can...
Field Scale Characterization of Geological Formations Using Percolation Theory
, Article Transport in Porous Media ; Vol. 92, issue. 2 , March , 2012 , p. 357-372 ; ISSN: 1693913 ; Masihi, M ; Shojaei, A ; Pishvaie, M ; King, P. R ; Sharif University of Technology
Abstract
The connectivity of high conductivity pathways in geological formations depend on the spatial distribution of geological heterogeneities that may appear on various length scales. Appropriate modeling of this is crucial within in hydrology and petroleum systems. The approach taken in this study is to use percolation theory to quantify the connectivity, hydraulic conductivity, and breakthrough time behavior between an injector and a producer within such systems. In particular, a three-dimensional overlapping sandbody model is considered which assumes that the geological formation can be split into either conductive flow units (i. e., good sands) or non-conductive units (i. e., poor sands). The...
Numerical simulation of the effect of visitor's movement on bacteria-carrying particles distribution in hospital isolation room
, Article Scientia Iranica ; Volume 24, Issue 3 , 2017 , Pages 1160-1170 ; 10263098 (ISSN) ; Abbassi, A ; Saidi, M. H ; Sharif University of Technology
Abstract
The aim of this paper is to simulate numerically the airflow induced by a walking visitor and its effects on the contaminant transport and ventilation system effectiveness. To this end, the following models will be used in this study: the Lagrangian Discrete Random Walk (DRW) model to trace the motion of BCPs, the dynamic mesh method to simulate the visitor movement, and the Reynolds Averaged Navier-Stokes (RANS) model to solve the airflow. The validation results of the numerical method are in full agreement with the available experimental data in the literature. The findings of the present study indicate that the visitor's movement has remarkable effect on the basic airflow, and the...
Assessing the contribution of different sources in atmospheric dispersion of PM2.5 and related health impact in a region of Qazvin, Iran
, Article Air Quality, Atmosphere and Health ; Volume 15, Issue 8 , 2022 , Pages 1379-1394 ; 18739318 (ISSN) ; Avami, A ; Mashayekhi, M ; Kianbakhsh, A ; Sharif University of Technology
Springer Science and Business Media B.V
2022
Abstract
Consumption of fossil fuels in residential, industrial, and transportation sectors has a significant contribution to air pollution and high attributable premature deaths. To target specific strategies for reducing health effects, the anthropogenic sources and their contributions should be identified. This article provides an integrated modeling approach to evaluate the sector-specific contributions of different PM2.5 sources on air pollution and relevant health impacts. The dispersion of emissions from different sources is modeled by the American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD), and the health impacts are estimated by the Environmental...
Tuning of random lasers by means of external magnetic fields based on the Voigt effect
, Article Optics and Laser Technology ; Volume 47 , April , 2013 , Pages 121-126 ; 00303992 (ISSN) ; Mahdavi, S. M ; Bahrampour, A. R ; Sharif University of Technology
2013
Abstract
It has been proposed that emission spectrum of random lasers with magnetically active semiconductor constituents can be made tunable by external magnetic fields. By employing the FDTD method, the spectral intensity and spatial distribution of electric field are calculated in the presence of an external magnetic field. It is numerically shown that due to the magneto-optical Voigt effect, the emission spectrum of a semiconductor-based random laser can be made tunable by adjusting the external magnetic field. The effect of magnetic field on the localization length of the laser modes is investigated. It is also shown that the spatial distribution of electric field exhibited remarkable...
Rock type connectivity estimation using percolation theory
, Article Mathematical Geosciences ; Volume 45, Issue 3 , 2013 , Pages 321-340 ; 18748961 (ISSN) ; Masihi, M ; Pishvaie, M ; King, P. R ; Sharif University of Technology
2013
Abstract
Complicated sedimentary processes control the spatial distribution of geological heterogeneities. This serves to make the nature of the fluid flow in the hydrocarbon reservoirs immensely complex. Proper modeling of these heterogeneities and evaluation of their connectivity are crucial and affects all aspects of fluid flow. Since the natural variability of heterogeneity occurs in a myriad of length scales, accurate modeling of the rock type connectivity requires a very fine scheme, which is computationally very expensive. Hence, this makes other alternative methods such as the percolation approach attractive and necessary. The percolation approach considers the hypothesis that a reservoir can...
Connectivity analysis of one-dimensional ad hoc networks with arbitrary spatial distribution for variable and fixed number of nodes
, Article IEEE Transactions on Mobile Computing ; Volume 11, Issue 10 , 2012 , Pages 1425-1435 ; 15361233 (ISSN) ; Ashtiani, F ; Sharif University of Technology
Abstract
In this paper, we propose an analytical approach to compute the probability of connectivity for one-dimensional ad hoc networks. The proposed analysis gives the exact probability of connectivity for an arbitrary distribution of nodes, provided that nodes are independently and identically distributed. We conduct separate analyses for two cases; in the first case, the number of nodes varies by time under a stationary distribution and in the second case, there is a fixed (known) number of nodes in the network. Using the approaches presented in this work, we are able to derive closed-form formulas for the probability of connectivity for some spatial distributions, while for more complicated...
Tunability of terahertz random lasers with temperature based on superconducting materials
, Article Journal of Applied Physics ; Volume 112, Issue 4 , 2012 ; 00218979 (ISSN) ; Bahrampour, A. R ; Mahdavi, S. M ; Hosseini, M ; Sharif University of Technology
2012
Abstract
We theoretically demonstrate the tunabiltiy of terahertz random lasers composed of high temperature superconductor YBCO and ruby layers as active medium. The considered system is a one-dimensional disordered medium made of ruby grain and YBCO. Finite-difference time domain method is used to calculate the emission spectrum and spatial distribution of electric field at different temperatures. Our numerical results reveal that the superconductor based random lasers exhibit large temperature tunability in the terahertz domain. The emission spectrum is significantly temperature dependent, the number of lasing modes and their intensities increase with decreasing temperature. Also, we make some...
Field scale characterization of geological formations using percolation theory
, Article Transport in Porous Media ; Volume 92, Issue 2 , 2012 , Pages 357-372 ; 01693913 (ISSN) ; Masihi, M ; Shojaei, A ; Pishvaie, M ; King, P. R ; Sharif University of Technology
2012
Abstract
The connectivity of high conductivity pathways in geological formations depend on the spatial distribution of geological heterogeneities that may appear on various length scales. Appropriate modeling of this is crucial within in hydrology and petroleum systems. The approach taken in this study is to use percolation theory to quantify the connectivity, hydraulic conductivity, and breakthrough time behavior between an injector and a producer within such systems. In particular, a three-dimensional overlapping sandbody model is considered which assumes that the geological formation can be split into either conductive flow units (i. e., good sands) or non-conductive units (i. e., poor sands). The...
Residual stresses in autofrettaged vessel made of functionally graded material
, Article Engineering Structures ; Volume 31, Issue 12 , 2009 , Pages 2930-2935 ; 01410296 (ISSN) ; Farrahi, G. H ; Maleki, M ; Nayeb Hashemi, H ; Vaziri, A ; Sharif University of Technology
Abstract
We used an extension of the Variable Material Property method for materials with varying elastic and plastic properties to evaluate the residual stresses in an autofrettaged thick vessel made of functionally graded metal-ceramic composite. It is shown that the reinforcement of the metal vessel by ceramic particles, with an increasing ceramic volume fraction from inner to outer radius, increases the magnitude of compressive residual stresses at the inner section of an autofrettaged vessel and thus, could lead to better fatigue life and load-carrying capacity of the vessel. A parametric study is carried out to highlight the role of ceramic particle strength and spatial distribution, as well as...
Towards an understanding of marine fouling effects on VIV of circular cylinders: Aggregation effects
, Article Ocean Engineering ; Volume 147 , 2018 , Pages 227-242 ; 00298018 (ISSN) ; Zeinoddini, M ; Soltanpour, M ; Zandi, A. P ; Seif, M. S ; Sharif University of Technology
Abstract
The current study is aimed at getting a further insight into the changes the fouling brings to the Vortex Induced Vibration (VIV) of circular cylinders. Instead of regular patterns considered in previous studies, using the Poisson Cluster Process, an aggregated spatial distribution was considered for the artificial marine fouling. This is believed to better simulate the natural settlement of the marine biofouling. Different coverage ratios and fouling shapes plus regular and aggregated distributions were considered. The towing tank VIV tests were conducted on elastically mounted rigid cylinders. The Reynolds number ranged from around 7.8 × 103 to 4.9 × 104. On the whole, the maximum...
Kinetic and morphological study of a magnesium ethoxide-based Ziegler-Natta catalyst for propylene polymerization
, Article Polymer International ; Volume 58, Issue 1 , 2009 , Pages 40-45 ; 09598103 (ISSN) ; Ramazani Saadatabadi, A ; Hiraoka, Y ; Kim, S. Y ; Taniike, T ; Terano, M ; Sharif University of Technology
2009
Abstract
Background: Kinetic andmorphological aspects of slurry propylene polymerization using a MgCl2-supported Ziegler-Natta catalyst synthesized from a Mg(OEt)2 precursor are investigated in comparison with a ball-milled Ziegler-Natta catalyst. Results: The two types of catalyst show completely different polymerization profiles: mild activation and long-standing activity with good replication of the catalyst particles for the Mg(OEt)2-based catalyst, and rapid activation and deactivation with severe fragmentation of the catalyst particles for the ball-milled catalyst. The observed differences are discussed in relation to spatial distribution of TiCl4 on the outermost part and inside of the...
Runaway electron energy measurement using hard x-ray spectroscopy in "damavand" tokamak
, Article Review of Scientific Instruments ; Volume 80, Issue 1 , 2009 ; 00346748 (ISSN) ; Iraji, D ; Farahbod, A. H ; Akhtari, K ; Rasouli, H ; Modarresi, H ; Lamehi, M ; Sharif University of Technology
2009
Abstract
Set of experiments has been developed to study existing runaway electrons in "Damavand" tokamak plasma upon characteristics of hard x-ray emissions produced by collision of the runaway electrons with the plasma particles and limiters. As a first step, spatial distribution of hard x-ray emissions on the equatorial plane of the torus was considered. Obtained spectra of hard x-ray emissions for different alignments of shielded detector indicate isotropic emissivity in the equatorial plane. This is in agreement with wide angle cone of bremsstrahlung radiations, deduced from the mean value of energy of the runaway electrons. The mean energy was calculated from the slope of the energy spectrum of...