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hassani-dorabadi--bahar
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Electronic Word of Mouth: Consumers' Motives for Participation in Online forums
,
M.Sc. Thesis
Sharif University of Technology
;
Modarres, Abdolhamid
(Supervisor)
Abstract
Consumers Communicate with each other to share information and feelings about products and brands. One important area to study personal influence in contemporary environment is online personal influence or electronic word of mouth. This study develops and tests consumers' motivations to participate in eWoM communication in online discussion forums. The main reason to choose Online forums is the huge number of eWoM discussions which occur in them. The main goal of this study is developing an aggregate framework for consumers' motives for opinion giving and seeking in online forums.To accomplish this goal we studied a comprehensive literature review, identified all motivations for WoM and...
Preparation and Application of Superhydrophobic Melamine Formaldehyde Modified by Graphene Sorbent for Extraction of Chlorobenzenes from Aqueous Samples by Needle-trap Device
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib (Supervisor)
Abstract
Superhydrophobic surfaces have attracted much attention in recent years due to their unique properties. Artificial superhydrophobic surfaces can be fabricated by employing chemical modifying a hierarchical structured surface (micro- and nanostructures) with a low surface free energy material. In this report, we used a simple one-step coating process to prepare superhydrophobic sorbents with a large surface area. Surface chemistry and porosity are fundamental parameters for an efficient sorbent capable of extracting low levels of analytes. Considering physical and chemical peroperties of chlorobenzenes, superhydrophobic materials make to be good sorbents. So in this project melamine...
Project Planning and Management Under Resource Constraint and Stochastic Activity Duration
, M.Sc. Thesis Sharif University of Technology ; Kianfar, Farhad (Supervisor)
Abstract
Most of the researches on project planning and scheduling have supposed that there is a complete and fixed information about the activities duration and amount of resources needed for project, but in reality we face lots of uncertainty in activities duration and required resources. In previous researches there are some cases which lead to more than one schedule for project, but in most of them they offer no solution for choosing between the schedules. In this project we are trying to make a nonlinear model of project environment by using Weibull distribution as activities duration and then we determine the input information by using the methods of probability encoding in decision analysis....
Reduced graphene oxide–melamine formaldehyde as a highly efficient platform for needle trap microextraction of volatile organic compounds
, Article Microchemical Journal ; Volume 157 , 2020 ; Allahdadlalouni, M ; Baktash, M. Y ; Bagheri, H ; Sharif University of Technology
Elsevier Inc
2020
Abstract
A superhydrophobic extractive phase was prepared and packed in a needle trap microextraction device for extraction of volatile organic compounds, followed by their determination by gas chromatography. The superhydrophobic phase was prepared by surface modification of melamine formaldehyde (MF) sponge embedded by reduced graphene oxide (rGO). The overall properties of the modified MF along with its high sorption capacity and low cost fabrication were indicative of its feasibility to be highly suitable for extraction of organic pollutants. The determined water contact angle (>150o) from the surface of melamine formaldehyde–reduced graphene oxide (MF–rGO) revealed its high affinity toward...
Nerve retraction during inferior alveolar nerve repositioning procedure: A new simple method and review of the literature
, Article Journal of Oral Implantology ; Volume 41 , Dec , 2015 , Pages 391-394 ; 01606972 (ISSN) ; Saadat, S ; Moshiri, R ; Shahmirzad, S ; Hassani, A ; Sharif University of Technology
Allen Press Inc
2015
Abstract
Nerve repositioning surgery is one of the treatments chosen for the patients with edentulous posterior atrophic mandible. Like any other treatments, this therapy has its advantages and disadvantages, indications and contraindications. The most important complication of this procedure is neurosensory disturbance. This problem may occur at different stages of the treatment. One common time when nerve damage happens is when the nerve is located outside the canal and drilling and insertion of the implant are performed. Accordingly, this report describes a simple and feasible method to retract and protect nerves outside the canal during the treatment of nerve transposition. This will reduce the...
Nerve retraction during inferior alveolar nerve repositioning procedure: a new simple method and review of the literature
, Article The Journal of oral implantology ; Volume 41 , 2015 , Pages 391-394 ; 01606972 (ISSN) ; Saadat, S ; Moshiri, R ; Shahmirzad, S ; Hassani, A ; Sharif University of Technology
2015
Abstract
Nerve repositioning surgery is one of the treatments chosen for the patients with edentulous posterior atrophic mandible. Like any other treatments, this therapy has its advantages and disadvantages, indications and contraindications. The most important complication of this procedure is neurosensory disturbance. This problem may occur at different stages of the treatment. One common time when nerve damage happens is when the nerve is located outside the canal and drilling and insertion of the implant are performed. Accordingly, this report describes a simple and feasible method to retract and protect nerves outside the canal during the treatment of nerve transposition. This will reduce the...
Thermal structure and energy budget for alghadir reservoir, iran
, Article Water Resources ; Volume 40, Issue 6 , 2013 , Pages 621-630 ; 00978078 (ISSN) ; Sharif University of Technology
2013
Abstract
Knowing the rate of evaporation from surface water resources such as channels and reservoirs is essential for precise management of the water balance. Few detailed evaporation studies exist for small lakes or reservoirs in arid regions of the world. In this study, monthly evaporation was determined by Bowen Ratio Energy Budget technique (BREB) for Alghadir reservoir (Saveh, Iran) from 1995-2007 and compared with class-A pan. Daily data were obtained from IMO (Iran Meteorological Organization) weather station, located near the reservoir, for all of these years. Some variations have been observed on the estimated evaporation of the energy budget at different years, ranging from 151 cm for 1997...
Role of Non-Dimensional Numbers in Density Current Stability
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
Density currents are occurred as a result of the intrusion of a dense fluid into a fluid with a different density. Density differences are typically caused by the difference in temperature, existence of solution or insoluble material and suspended solids. A special kind of density current is called a turbidity current which is a sediment-laden density current. This is a kind of flow which is driven by the force of gravity on suspended sediment particles that causes an excess fractional density with respect to the surrounding ambient fluid. In this work, the 2-D sediment-laden density current on a sloping surface of the channel is investigated through experiments. The channel is 12 m long,...
Experimental Study on Deposition Behavior of Turbidity Current
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
Density currents are occurred as a result of the intrusion of a dense fluid into a fluid with a different density. Density difference is the main agent of current’s movement. These currents are observed in nature numerously and they are one of the main reasons of the erosion and transportation of deposition in oceans, seas and rivers. Investigation of these currents is of great importance especially in dams’ reservoir as major cause of deposition and reduction of reservoir’s efficency. Density differences are typically caused by the difference in temperature, existence of solution or insoluble material and suspended solids. In this work, density current is studied experimentally. Density...
Numerical Assessment of Optimum Baffle Configuration and Hydrodynamics of Settling Tanks
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
Sedimentation tanks are channels designed for sedimentation of suspended solids in water. These tanks are one of the most important parts of water treatment plants and their performance directly affects the functionality of water treatment plants. Therefore, researchers have tried to find better designs of sedimentation tanks. Among several design methods have been presented, modification of the geometry of tanks by installing baffles is one of the most effective and economic methods. According to the importance of performance improvement of industrial sedimentation tanks as well as the diversity in reported results, development and completion of previous studies seem to be necessary. In...
Vorticity-Bases Adaptive Mesh Refinement for Upscaling of Highly Heterogeneous Porous Media
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
The results of numerical simulation of underground flows are greatly affected not only by the discretization method of flow equations, but also by the way that the geological domain is upscaled. Including the detailed knowledge of heterogeneous permeability distribution is mostly neither feasible nor computationally efficient. So it is important to develop efficient grid generation and upscaling methods to simplify the fine-scale flow model while still including the impact of the heterogeneities as far as possible. Thus regions where parameters of interest have larger values or higher changes require finer grid blocks and regions with lower values or minor changes should have coarser grid...
Upscaling and Simulation of Two-Phase Flow in Porous Media
, Ph.D. Dissertation Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
Advanced reservoir characterization methods can yield geological models at a very fine resolution, containing 1011-1018 cells while the common reservoir simulators can handle much fewer numbers of cells due to computer hardware limitations. The process of coarsening the fine-scale model to simulation models is known as upscaling. There are three fundamental steps in the procedure of upscaling, i.e. defining the coarse grid geometry, calculating the average properties for the generated coarse grid and simulation of the two-phase flow equations on the generated coarse-scale model. In this thesis, the focus will be on investigating the applicability of optimization in the context of coarse grid...
Numerical Simulation of Glucose Metabolism and Hepatocyte Viability within a Microfluidic
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
The advent of microfluidics as suitable environments for culturing cells is associated with some challenges such as shear stresses applied on the cells. In fact, hepatocytes lose their function as exposed to high shear stresses similar to other cell types. Moreover, among all factors needed for cell viability, feeding hepatocytes with adequate oxygen is of great importance due to their high demand for oxygen compared the other cells. In this thesis, different types of cultures including 2D and 3D has been used in order that shear stresses would be in allowed range and provision of hepatocytes with sufficient oxygen concentrations has been ensured as well. In addition to supplying hepatocytes...
Optimum experimental condition in oxygen gas-assisted low power Nd:Yag laser cutting
, Article Modern Physics Letters B ; Volume 23, Issue 6 , 2009 , Pages 877-890 ; 02179849 (ISSN) ; Golnabi, H ; Sharif University of Technology
2009
Abstract
The optimum condition for the reactive gas-assisted Nd:YAG laser cuttings is described in this article. The cut kerf width is investigated for a laser power range of 50-170 W and a gas pressure of 1-6 bar for steel and mild steel materials. Variation of sample thickness, material type, gas pressure and the laser power on the cut width and slot quality are considered in this study. An overall 338 experiments at different experimental conditions are performed and the kerf results are compared. Optimum conditions for the steel and mild steel materials with a thickness range of 1-2 mm are obtained. The optimum condition for the steel cutting results in a minimum kerf width of 0.2 mm at a laser...
Numerical Simulation of Discharged Liquid Jet from Desalination Plants and Investigation Mixing Characteristics with Surroundings
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
Today, due to the decline of drinkable water, many desalination plants have been established and operated around the world. Disposal of these brines, which have higher density and temperature than receiving water, causes many environmental impacts. Industrial power plants discharge these effluents into the seawater body mostly as submerged jets due to their higher effectiveness. Many experimental researches have been done on the negative and positive buoyant jet that discharged form desalination plants. But a few numerical studies have been done with investigating the full Navior-Stokes equations and they have been flawed in modeling. For example, some of these models have been able to...
Effects of Heart Dynamic Motion on Blood Hemodynamics and LDL Accumulation in Coronary Bifurcation
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
In this thesis, the effect of heart dynamic motion and pulsatile inflow on blood hemodynamics and LDL permeation into the arterial wall in a 3-D coronary artery bifurcation was investigated. To determine the effect of each factor alone and simultaneous effect of both factors i.e. heart dynamic motion and pulsatile inflow, flow simulations were performed in four cases i.e. steady-static, steady-dynamic, pulsatile-static, and pulsatile-dynamic. The results of flow simulations showed that dynamic geometry and pulsatile inflow have considerable impact on temporal variations of wall shear stress (WSS), even though the effect of pulsatile inflow on WSS variation dominates over the effect of...
Numerical Investigation of the Seabed Inclination Effects on Mixing Characteristics of the Brine Discharged Jet from Desalination Plants
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
A large number of desalination plants have been established to overcome the drinkable water scarcity in the world. These plants produce saline water as effluent, which is often discharged into local sea water. One of the applicable methods to dispose these kinds of effluents is to install an inclined nozzle below the water’s surface. Hence, an inclined negatively buoyant jet (INBJ) forms which is often fully turbulent due to the high discharge velocity. Local environmental characteristics affect the dynamics and mixing behavior of INBJs. One of these characteristics is the sea bed slope, on which the present study has been focused. Large eddy simulations (LES) are performed in the present...
Control of Blood Flow by Endothelial-Secreted Biochemicals NO, Ca2+ and Growth Factor VEGF: Numerical Simulation Using Lattice Boltzmann-Finite Difference Hybrid
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
Endothelial cells that cover the inner wall of blood cells and are sensitive to receiving mechanical signals play important role in regulating many vital activities of the human body especially the function of the cardiovascular system. One of the factors affecting the mechanical functions of these cells is the shear stress applied to them. Due to blood velocity increasing or decreasing the endothelial cells shear stress change and leads to some chemical reactions and finally releasing biochemical substances including Nitrogen-Monoxide and Calcium-ion. Nitrogen-Monoxide produced by endothelial cells by affecting the smooth muscle cells in the vessel wall causes dilating of the vessel wall,...
Continuum Modeling of Biological Growth of Atheroma in Coronary
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
Atherosclerosis is a vascular disorder caused by inflammation of the arterial wall. This inflammation leads to the accumulations of low-density lipoprotein (LDL) cholesterol, monocytes, macrophages and fat-laden foam cells at the site of inflammation, often referred to as plaque formation. This work uses a mathematical model for simulating the deposition of atheroma plaque in coronary arteries. In this study, the effect of time average wall shear stress (TAWSS), oscillatory shear index (OSI), non-Newtonian characteristics of blood and variable hematocrit values on the occurrence of atherosclerosis in a three-dimensional coronary artery was numerically investigated. Simulations was conducted...
Numerical and Experimental Modeling of the Thermal-Saline Jet Discharge from : Thermal-Saline Jet Water Desalination Plants and Providing a Practical Solution to Reduce its Environmental Impacts
, Ph.D. Dissertation Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
More than 80% of desalination units in the Persian Gulf use multi-stage flash (MSF) technology. The discharge of effluent from these units sometimes causes severe impacts to the marine environment due to the increase in temperature and salinity around the discharge point. In the current thesis, the geometrical, mixing and turbulence characteristics of the discharge of thermal-saline inclined jets under the water surface, similar to the effluent of MSF units, are numerically investigated by developing the buoyantBoussinesqPimpleFoam solver in the OpenFoam open-source software, using the LES turbulence model and the dynamic Smagorinsky subgrid scale and the UNESCO equation of state. The...