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azari--hossein
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Conversion of Persian Colloquial Texts into Official Texts using Unsupervised Learning Methods
, M.Sc. Thesis Sharif University of Technology ; Sameti, Hossein (Supervisor)
Abstract
Today, the production of colloquial texts in messengers, search engines, and question and answer systems has increased significantly, while text documents in other fields have a formal tone and style. Thus, there is a need for a system to convert these texts from colloquial form to the formal style. Attention to this need in non-Persian languages has also been recently and seriously felt, but almost at the time of writing, an efficient system has not been offered, and this issue requires more work in Persian than in languages such as English. In general, transferring texts from one form to another falls into the category of natural language processing applications and is called "style...
Level-Set Techniques for Facies Identification in Reservoir
Modeling
,
M.Sc. Thesis
Sharif University of Technology
;
Razvan, Mohammad Reza
(Supervisor)
;
Azari, Hossein
(Supervisor)
Abstract
The success of oil recovery depends, among other factors, on the ability to provide reliable simulations of the reservoir performance. The reservoir dynamics are usually modeled by a distributed parameter dynamic system whose parameters represent the petrophysical properties of the reservoir. A proper characterization of those reservoir properties is fundamental for an accurate reservoir simulation. The petrophysical properties are highly heterogeneous and only a limited number of measurements are available at certain locations in the reservoir. Therefor, in ordet to obtain accurate prediction of the reservoir performance, it is essential to possess reliable estimates of the petrophysical...
Evaluating Effect of Major Approach Median on Minor Approach Drivers’ Behavior at Major-Minor Intersections With Stop Control
, M.Sc. Thesis Sharif University of Technology ; Vaziri, Manouchehr (Supervisor)
Abstract
At major-minor intersections with no timing and signal control, with comparison to those with signal control, a lower level of control is imposed on intersection’s traffic. So the driver’s behavior has more effective and important role on geometric and traffic design of intersection. Therefore, recognizing drivers’ behavior at this kind of intersections seems to be vital. In this research drivers’ behavior in big cities in Iran at major-minor intersections has been studied. For this purpose, 7 major-minor intersections which have stop control at minor approach and median at major approach have been selected and shot. After extraction of primary data from taken digital video films and...
Preparation of PVA nanocomposites using salep-reduced graphene oxide with enhanced mechanical and biological properties
, Article RSC Advances ; Volume 5, Issue 112 , 2015 , Pages 92428-92437 ; 20462069 (ISSN) ; Pourbadiei, B ; Doroudian, M ; Azari, S ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
Salep, known as a biodegradable polysaccharide, is hydrolyzed and used as both a reducing agent and stabilizer for graphene oxide (GO). The functionalized reduced graphene oxide (f-rGO) is homogenously dispersed in an aqueous solution of poly(vinyl alcohol) (PVA). PVA based hydrogel and film nanocomposites are prepared and proposed as new biomaterials for tissue engineering applications. The mechanical properties of the film nanocomposites are investigated with varying content of f-rGO, glycerol and citric acid as a reinforcing agent, a plasticizer agent and a cross linking agent respectively. For the first time, chemically cross linked PVA hydrogels are synthesized using...
Injectable chitosan/κ-carrageenan hydrogel designed with au nanoparticles: A conductive scaffold for tissue engineering demands
, Article International Journal of Biological Macromolecules ; Volume 126 , 2019 , Pages 310-317 ; 01418130 (ISSN) ; Doroudian, M ; Ahadpour, A ; Azari, S ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Scaffolds for tissue engineering of specific sites such as cardiac, nerve, and bone tissues need a comprehensive design of three dimensional materials that covers all aspects of chemical composition and physical structures, required for regeneration of desired cells. Hydrogels, possessing highly hydrated and interconnected structures, are promising materials for tissue engineering applications. Improvement of an injectable hydrogel from biocompatible polysaccharides and poly‑N‑isopropyl acryl amide enriched with Au nanoparticles are the main goal of this study. Two main enhancements in this study are included mixture design of the components and addition of Au nanoparticles to access a...
A Detailed Nonlinear Finite Element Model of the L4-L5 Motion Segment to Predcit Spinal Loads during in Vivo Activities
, M.Sc. Thesis Sharif University of Technology ; Arjmand, Navid (Supervisor) ; Parnianpour, Mohammad (Supervisor)
Abstract
Several geometrically-detailed passive finite element (FE) models of the lumbar spine have been developed and validated under in vitro loading conditions. As these models are devoid of muscles, they are either not used to simulate in vivo activities or muscle forces are modeled by a hypothetical compressive follower load (FL). A number of symmetric and asymmetric static tasks were first simulated using a validated musculoskeletal model of the thoracolumbar spine to predict trunk muscle forces. The predicted muscle forces along with the gravity loading were then applied to a passive FE model of the L4-L5 motion segment (developed and validated here) to estimate load sharing among the disc,...
Synthesis and characterization of new triphenylamine-based dyes with novel anchoring groups for dye-sensitized solar cell applications
, Article Journal of Materials Science: Materials in Electronics ; Volume 28, Issue 2 , 2017 , Pages 1859-1868 ; 09574522 (ISSN) ; Hosseinzadeh, B ; Azari, M ; Ghahary, R ; Sharif University of Technology
Springer New York LLC
2017
Abstract
Three new chromophores based on the triphenylamine (MM, DM, DN) with various novel electron withdrawing anchoring groups have been synthesized for use in dye-sensitized solar cells (DSSCs). The sensitizers were characterized by 1H and 13C NMR, Mass, UV–Vis, and electrochemical analysis. The HOMO and LUMO electron distributions of the sensitizers were calculated using density functional theory on a B3LYP level for geometry optimization. The DSSC device based on DM dye showed the best photovoltaic performance among MM and DN dyes: maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 98 %, short circuit current (JSC) of 4.58 mA/cm2, open circuit voltage (VOC) of...
Electrokinetic properties of asphaltene colloidal particles: determining the electric charge using micro electrophoresis technique
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 541 , 2018 , Pages 68-77 ; 09277757 (ISSN) ; Abolghasemi, E ; Hosseini, A ; Ayatollahi, S ; Dehghani, F ; Sharif University of Technology
Elsevier B.V
2018
Abstract
In this work, the electrokinetic properties of asphaltene particles have been investigated. Micro-electrophoresis method by applying DC electric field, was utilized to different mixtures containing asphaltene to determine its electric charge. It was observed that in the case of using n-heptane and its mixture with toluene (heptol), the asphaltene particles were showed to be positively charged however for toluene itself, they expressed no tendency toward the electrodes. While it is expected that larger asphaltene aggregates carry higher electric charge, the results contradictorily showed that they are mainly governed by gravity rather than electro-static force and that “aggregation” reduces...
A combined passive and active musculoskeletal model study to estimate L4-L5 load sharing
, Article Journal of Biomechanics ; Volume 70 , March , 2018 , Pages 157-165 ; 00219290 (ISSN) ; Arjmand, N ; Shirazi Adl, A ; Rahimi Moghaddam, T ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
A number of geometrically-detailed passive finite element (FE) models of the lumbar spine have been developed and validated under in vitro loading conditions. These models are devoid of muscles and thus cannot be directly used to simulate in vivo loading conditions acting on the lumbar joint structures or spinal implants. Gravity loads and muscle forces estimated by a trunk musculoskeletal (MS) model under twelve static activities were applied to a passive FE model of the L4-L5 segment to estimate load sharing among the joint structures (disc, ligaments, and facets) under simulated in vivo loading conditions. An equivalent follower (FL), that generates IDP equal to that generated by muscle...
A combined passive and active musculoskeletal model study to estimate L4-L5 load sharing
, Article Journal of Biomechanics ; 2017 ; 00219290 (ISSN) ; Arjmand, N ; Shirazi Adl, A ; Rahimi Moghaddam, T ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
A number of geometrically-detailed passive finite element (FE) models of the lumbar spine have been developed and validated under in vitro loading conditions. These models are devoid of muscles and thus cannot be directly used to simulate in vivo loading conditions acting on the lumbar joint structures or spinal implants. Gravity loads and muscle forces estimated by a trunk musculoskeletal (MS) model under twelve static activities were applied to a passive FE model of the L4-L5 segment to estimate load sharing among the joint structures (disc, ligaments, and facets) under simulated in vivo loading conditions. An equivalent follower (FL), that generates IDP equal to that generated by muscle...
Investigation of Asphaltene Electro-deposition Under Dynamic Flow Conditions
, M.Sc. Thesis Sharif University of Technology ; Taghikhani, Vahid (Supervisor) ; Ayatollahi, Shahabodin (Supervisor)
Abstract
Asphaltene, known as the heaviest and the most polar component of the crude oil, can precipitate because of the changes in the fluid condition such as pressure, temperature and composition. Asphaltene deposition causes major problems during oil production, in the form of fluid viscosity changes, wellbore damage and fouling in pipelines. The remediation of these problems is very expensive and needs to halt down the crude oil production. The use of electric field has been proposed recently as clean and cheap technique that could also be applied during the production period. In this work, the effect of electric potential on asphaltene precipitation in both static and dynamic modes has been...
Design and Fabrication Bi-fuel Gas Turbine Combustion Chamber Basis of Turbocharger
, M.Sc. Thesis Sharif University of Technology ; Farshchi, Mohammad (Supervisor) ; Hajilouy Benisi, Ali (Co-Advisor)
Abstract
This research is done as a continuation of previous efforts to develop a turbojet engine from a turbocharger at departments of mechanical and aerospace engineering of Sharif University of Technology and describes the necessary steps in order to design and build a dual fuel combustion chamber for a small, turbocharger based turbojet engine. At first, zero-dimensional analysis is done using a code written in Matlab. Using this code, matching of the compressor and turbine in the turbojet thermodynamic cycle is verified and the operating line of the turbojet engine has been extracted. Henceforth, operating conditions of the combustion chamber to start design process is determined. In designing...
Human Capital Development and Utilization Methodology in a Public Sector Organization: Dynamic Capability Approach
, M.Sc. Thesis Sharif University of Technology ; Kermanshah, Ali (Supervisor) ; Sanjari, Ahmad Reza (Supervisor)
Abstract
It is proposed, in this research, a methodology for a public sector organization to integrate policy making in human capital development and utilization area. In this case the researcher used system dynamics method for modeling and analyzing the situation, to describe the mechanisms that produce the difficulties in the organization. The researcher mentioned the differences between public sector and profit organization, in designing the main part of the model and also the use of dynamic capability approach in designing human capital development parts of it. The model built in this research, describe the events before and after the 1990s separately, according to the different policy making...
Analysis of communication systems using iterative methods based on Banach's contraction principle
, Article 2007 6th International Conference on Information, Communications and Signal Processing, ICICS, Singapore, 10 December 2007 through 13 December 2007 ; 2007 ; 1424409837 (ISBN); 9781424409839 (ISBN) ; Saberian, M. J ; Akhaee, M. A ; Nasiri Mahallati, R ; Marvasti, F ; Sharif University of Technology
2007
Abstract
In this paper, the application of a well known mathematical theorem, Banach's fixed point theorem [1], is investigated in iterative signal processing in communications. In most practical communication systems some sort of a contraction mapping is used to enhance the operation of the system. Thus, using a suitable iterative approach, one can set the system in its fixed point and hence, the distortion produced in the transmitter, channel and the receiver can be compensated. In other words, a loosely designed transceiver can be enhanced by an iterative method. In order to verify the truth of the proposed iterative method, the distortion of A/D and D/A converters is compensated at the receiver....
Calculation of the Energy Release Rate of Nano-Cracks in FCC Materials Via the Many Body Atomic Scale FEM
, M.Sc. Thesis Sharif University of Technology ; Mohammadi Shodja, Hossein (Supervisor)
Abstract
Since the classical continuum theory fails to deal with the problems associated with defects, stress concentrators, and relevant deformation phenomena in solids, alternative approaches that can detect the atomistic nature of materials' fracture are required. The deficiency of the capture the size effect which yields delusively high values for some components of the stress field right on the edge of the stress concentrators, and its weakness in describing the complex interaction between small inhomogeneities, cracks and the like when they are only a few nanometers apart, are among some of the disadvantages of the classical approach. In recent years, however, atomistic methods are emerging to...
Cytotoxicity and cell cycle effects of bare and poly(vinyl alcohol)-coated iron oxide nanoparticles in mouse fibroblasts
, Article Advanced Engineering Materials ; Volume 11, Issue 12 , 2009 , Pages B243-B250 ; 14381656 (ISSN) ; Simchi, A ; Vali, H ; Imani, M ; Shokrgozar, M. A ; Azadmanesh, K ; Azari, F ; Sharif University of Technology
2009
Abstract
Super-paramagnetic iron oxide nanoparticles (SPIONs) are recognized as powerful biocompatible materials for use in various biomedical applications, such as drug delivery, magnetic-resonance imaging, cell/protein separation, hyperthermia and transfection. This study investigates the impact of high concentrations of SPIONs on cytotoxicity and cell-cycle effects. The interactions of surfacesaturated (via interactions with cell medium) bare SPIONs and those coated with poly(vinyl alcohol) (PVA) with adhesive mouse fibroblast cells (L929) are investigated using an MTT assay. The two SPION formulations are synthesized using a co-precipitation method. The bare and coated magnetic nanoparticles with...
Semisolid Stir Joining of As-Cast Silicon-Aluminum Bronze
, M.Sc. Thesis Sharif University of Technology ; Kokabi, Amir Hossein (Supervisor) ; Ashuri, Hossein (Supervisor)
Abstract
Aluminum Bronzes have many applications in marine environments. These alloys suffer from both hot cracking and cold cracking. In order to overcome the hot cracking and cold cracking, Semisolid Stir Joining method and a proper thermal cycle was used respectively. Effects of temperature, stirring rate, and tool type were investigated in Semisolid Stir joining method. In this method, butt joint design was used in order to place specimens, and the specimens were heated up to specific temperatures (920, 925, 930°C). A stirrer (Cylindrical and Grooved tool) with three rotational speeds (800, 1200, 1600 RPM) was introduced into the stir weld seam. Welded specimens were cooled to the 900°C...
The Study of Eliminating Gender Gap in Iran Labor Market on Participation Rate of Married Urban Women
, M.Sc. Thesis Sharif University of Technology ; Rahmati, Mohammad Hossein (Supervisor) ; Joshaghani, Hossein (Supervisor)
Abstract
The low female labor force participation rate in the Iranian labor market relative to the global average and even to countries that do not differ significantly from the socio-economic characteristics of our country is one of the important questions of the Iranian labor market. In this study, we seek to answer the question of whether the economic participation rate of married women will increase if the gender gaps in wages, job findings and job losses among women and men are eliminated in the Iranian labor market. To answer this question using household expenditure and income data and labor force data, we show that between the two categories of occupations, in terms of the share of women's...
Graph homomorphisms through random walks [electronic resource]
, Article Journal of Graph Theory ; 2003, Volume 44, Issue 1, pages 15–38 ; Hajiabolhassan, Hossein ; Sharif University of Technology
Abstract
In this paper we introduce some general necessary conditions for the existence of graph homomorphisms, which hold in both directed and undirected cases. Our method is a combination of Diaconis and Saloff–Coste comparison technique for Markov chains and a generalization of Haemers interlacing theorem. As some applications, we obtain a necessary condition for the spanning subgraph problem, which also provides a generalization of a theorem of Mohar (1992) as a necessary condition for Hamiltonicity. In particular, in the case that the range is a Cayley graph or an edge-transitive graph, we obtain theorems with a corollary about the existence of homomorphisms to cycles. This, specially, provides...
Unique list-colourability and the fixing chromatic number of graphs [electronic resource]
, Article Discrete Applied Mathematics ; Volume 152, Issues 1–3, 1 November 2005, Pages 123–138 ; Hajiabolhassan, Hossein ; Sharif University of Technology
Abstract
In this paper we introduce a chromatic parameter, called the fixing chromatic number, which is related to unique colourability of graphs, in the sense that it measures how one can embed the given graph G in G∪Kt by adding edges between G and Kt to make the whole graph uniquely t-colourable. We study some basic properties of this parameter as well as its relationships to some other well-known chromatic numbers as the acyclic chromatic number. We compute the fixing chromatic number of some graph products by applying a modified version of the exponential graph construction