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shojaei--razieh
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Ezafe Recognition Using Dependency Parsing
, M.Sc. Thesis Sharif University of Technology ; Bahrani, Mohammad (Supervisor) ; Shojaei, Razieh (Co-Supervisor)
Abstract
Ezafe is regarded as one of the most controversial and challenging issues in different Persian Language Processing (NLP) fields. It is recognized and pronounced but usually not written. So, this results in a high degree of ambiguity in Persian texts. Dependency grammar plays a significant role in optimization problems. So, to recognize the position of Ezafe in a sentence, this grammar is used in this current study. This method helps speed up computer operations and use low memory. Within this framework, first we take a close look at Ezafe distribution in Persian text. We use Uppsala Persian Dependency Corpus (2015) to analyze parsed sentences. The Ezafe constructions under study include...
A Semantic Valency Lexicon for Persian Predicates and Visualization of their Relations
, M.Sc. Thesis Sharif University of Technology ; Khosravi Zadeh, Parvaneh (Supervisor) ; Shojaei, Razieh (Supervisor)
Abstract
The highest and most difficult layer of Natural Language Processing, is the understanding of meaning. As a result, lexicons and annotated corpora are of the utmost importance in this area. However, the lack of such semantic resources, especially in Abstract Meaning Representation (AMR), is one of the main issues in this field for Persian Language. This work by modeling PropBank, a semantic valency lexicon for English predicates, is the first step towards building such lexicons for Persian Language with the focus on AMR. Thus, a guideline describing how to annotate the Persian predicates is provided which first evaluates the common structures between the two languages and then focuses on the...
, M.Sc. Thesis Sharif University of Technology ; Farzaneh, Forouhar (Supervisor)
Abstract
In recent years due to the advances in semiconductor technology and the ability to implement small-scale manufacturing, communication at 60 GHz band receive more attention than ever has been. The use of this frequency band is not only about 7-9 GHz unlicensed broadband access provided, but getting smaller devices make it possible to use multiple antennas at the transmitter and receiver, and thus taking advantage of multiple input – multiple output systems. Antennas used in these systems should have features such as small size , low weight, high gain and bandwidth and also they should keep their high efficiency and gainat high frequency range (about a few GHz ). To achieve these features...
Design and Preparation of a Persian Semantic Corpus Using Abstract Meaning Representation
, M.Sc. Thesis Sharif University of Technology ; Bahrani, Mohammad (Supervisor) ; Shojaie, Razieh (Supervisor)
Abstract
To keep in line with the day to day advancements in the fields of computational linguistics and natural language processing, and the growing attention of researchers to semantic processing, this thesis presents the design and preparation of a Persian semantic corpus using Abstract Meaning Representation (AMR). This semantic representation pairs each sentence with a single rooted, acyclic, directed graph, which is human and computer readable. Moreover, this representation paves the way for the creation of large semantic corpora. In order to bring such benefits to Persian, in this thesis we present solutions for representing Persian sentences in the framework of AMR. Moreover, a corpus of 150...
Persian Causative/Inchoative Alternation from an LFG Perspective
, M.Sc. Thesis Sharif University of Technology ; Khosravizadeh, Parvaneh (Supervisor) ; Shojaee, Razieh (Supervisor)
Abstract
This study attempts to describe and analyze Persian speakers’ linguistic knowledge of different types of causative and inchoative constructions within the framework of Lexical Functional Grammar (LFG). In order to do so, different studies on Persian causative alternations within theories other than LFG as well as causative alternations in other languages within LFG are reviewed. Next, different types of causative constructions are categorized conceptually and structurally after they are extracted from Bijankhan corpus (2005). Then they are analyzed syntactically and semantically. In this regard, we represent syntactic and semantic structures based on LFG as a monostratal theory. After that,...
Persian Compound Verb Database with the Verbal Element: “Shodan”
, M.Sc. Thesis Sharif University of Technology ; Khosravizadeh, Parvaneh (Supervisor) ; Shojaie, Razieh (Supervisor)
Abstract
Compound verbs (CVs) and its components, have been widely discussed in previous linguistics' researches as one of the most important and fundamental constructions of Persian language. Nevertheless most of the arguments and assumptions in those researches align with each other and studying CVs from another aspect with a different viewpoint has not been considered very much in order to solve nodes and issues in this area. We have endeavored in this thesis to review and criticize the portrayed definitions of the CVs, reconsider this construction and the syntactical and semantical roles of verbal and non-verbal elements in this combination from another point of view, and revise the previous...
A numerical investigation on the cure cycle of composite brake blocks
, Article International Polymer Processing ; Volume 21, Issue 4 , 2006 , Pages 421-431 ; 0930777X (ISSN) ; Sharif University of Technology
Carl Hanser Verlag
2006
Abstract
Composite friction materials used in the braking system of vehicles are composed of different ingredients (typically up to 20 materials). The overall physical properties of these products are determined by the type and percentage of the individual ingredients in the final composition and consequently, may differ from one product to another. This paper studies the cure characteristics of railroad composite brake blocks during compression molding. Numerical simulations using the control volume/finite element method (CV/FEM) are utilized to predict temperature fields and cure conversion during the process. As railroad brake blocks are normally thick-sectioned parts, a three-dimensional modeling...
Numerical simulation of three-dimensional flow and analysis of filling process in compression resin transfer moulding
, Article Composites Part A: Applied Science and Manufacturing ; Volume 37, Issue 9 , 2006 , Pages 1434-1450 ; 1359835X (ISSN) ; Sharif University of Technology
2006
Abstract
In compression resin transfer moulding (CRTM), resin flows inside a mould filled with fibrous reinforcement as a result of resin injection and mould compression. This process facilitates the resin flow through the fibrous reinforcement particularly for high fiber content parts. This paper presents the numerical simulation of filling process of CRTM in full three-dimensional domain. A mathematical model of three-dimensional resin flow inside the CRTM mould is presented. An effective elastic modulus is introduced for multi-layer preforms connecting the mould closing speed to deformation rate of individual layers. Control volume/finite element method (CV/FEM) is used and the numerical algorithm...
A numerical study of filling process through multilayer preforms in resin injection/compression molding
, Article Composites Science and Technology ; Volume 66, Issue 11-12 , 2006 , Pages 1546-1557 ; 02663538 (ISSN) ; Sharif University of Technology
2006
Abstract
In resin injection/compression molding (RI/CM), a preform often comprises layers of different fiber reinforcements. Each fiber reinforcement has unique through thickness and in-plane permeabilities as well as compressibility, creating a heterogeneous porous medium in the mold cavity. In the present article, numerical simulation is utilized to investigate the filling process of RI/CM in such a heterogeneous porous medium. The filling stage is simulated in a full three-dimensional space by using control volume/finite element method and based upon an appropriate filling algorithm. The flow in the open gap which may be present in the mold cavity is modeled by Darcy's law using an equivalent...
Investigation of the Role of Fiber Reinforcement on the Performance of Rubber Based Friction Material
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor)
Abstract
Friction composites, as a part of vehicle safety system, should hold some characteristics such as high wear resistance, low weight, durability, low noise, stable friction coefficient, availability and low price. It is very interested to use mixture of rubber and resin in friction materials to reach good properties of both rubber and resin simultaneously. This mixture is especially used in railway’s brake pads. Fibrous reinforcement is another important ingredient in friction composites. Asbestos used to be the most significant fibrous reinforcement due to its appropriate tribological specifications but the recent ban on asbestos by environmental protection agency has forced the friction...
Layer of Protection Analysis (LOPA) for Nitroglycerine Production
,
M.Sc. Thesis
Sharif University of Technology
;
Rashtchian, Davood
(Supervisor)
Abstract
Nitroglycerine is an oily liquid and in pure form it is colorless. It is the main component of high explosives such as dynamites, and an essential ingredient of smokeless, double base propellants. The production of nitroglycerine has to solve the problems that arise from the extremely high mechanical sensitivity of the substance and the chemical instability of impure materials. Without sufficient control and mitigation of hazards, incidents have led to severe consequences, such as explosions, and threats to human lives, properties, and the environment. In this study, the hazard and operability study method is used to identify the existing hazards in the nitroglycerine production plant. Then,...
Experimental and Theoretical Investigation on the Frictional Performance of Friction Materials of Brake System
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor)
Abstract
Various composite friction materials containing 40 vol.% organic binder (phenolic resin plus styrene-butadiene-rubber (SBR)) with varying phenolic-resin/SBR ratio were prepared. The content of phenolic resin in each composite was indicated by the resin value (RV) index ranging between 0-100%. The composites with RVs greater than 50% form resin-based friction materials in which the primary binder is the phenolic resin. For RVs less than 50%, the composites become the rubber-based materials where the primary binder is the SBR. The analysis of mechanical properties exhibited that the conformability of the composites increases upon incorporation of SBR. The frictional analysis revealed that type...
, M.Sc. Thesis Sharif University of Technology ; Farhanieh, Bijan (Supervisor)
Abstract
Development of cities as well as population growth causes to development of public transportation especially subway lines. Fire is the one of the most important issues that may occur in subways. The difference in flame size, emission heat, smoke and pollutants generation of subway fires attracts an especial attention of fire investigators. The emergency ventilation of subways in the case of fire should have the ability of discharging heat, smoke and pollutants from passenger escape route and preparing a safe place for a specific duration. The aim of this research is simulating fire in subway stations and defining proper regional fire scenarios to prepare a safe route for passengers escape....
Investigation on the Effect of MWCNT on the Properties of NR/SBR Rubber Blend and the Comparison with Conventional and High Structure Carbon Blacks
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor)
Abstract
In recent years, using the nanoparticles has caused a great revolution and development into the materials structure and the polymer science developed corresponding to important role of it in consumer goods. So Carbon Nano Tubes (CNTs) belonging to the precious physical, Mechanical and thermal properties has been studied. The CNT is mixed by mechanical and solution methods with elastomeric matrix. In this research the mechanical method used, because of industrial applications. Although, there are many challenges against dispersion owing to weak cohesion between CNTs and matrix in the mechanical method. The progress in rubber composites reinforced by CNTs and other reinforcement and as well as...
Fabrication and Characterization of Phenolic Resin/Glass Fiber/Organoclay Nanocomposites
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor)
Abstract
In this research the effects of addition of clay in phenolic glass fiber reinforced composite has been investigated. Layered clay/phenolic nanocomposite resin systems were first prepared with 0.5, 1.5 and 2.5 wt% of Cloisite Na+ (CN) and Cloisite 30B (CB). After that the suspension was hold in an ultrasonic bath for 30 min in order to enhance nanodispersion of the clay platelet within the resin. The phenolic/clay solution was used to impregnate the glass fabric using the solvent impregnation method. After suspension for 2 days in the room with natural condition, the impregnated fabrics were pre-cured at 135 ˚C in an oven for 3.5 min to obtain B-stage prepregs. Seven layers of prepregs (150...
Modeling and Optimization of Composite Brake Friction Materials Formulation
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor)
Abstract
Automotive brake pad is one of the most widely used composites. Commonly, more than 10 components are applied to make these materials and due to the large number of components and interactions between them, choice, explaination of the behavior and optimization of brake friction materials are some industry's challenges. Until now, some methods have been presented to design and optimization of these materials, but due to different complexities, there is lack of practical method that could be used for explaining the tribological behavior, engineering calculation and optimization of brake friction materials. Today, formulation of the current brake pads in the industry has mainly come from trial...
An Investigation on the Behavior of Nanoparticle Filled Brake Friction Materialls
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor)
Abstract
The most common type of polymer based composite friction materials are usually in vehicles as the brake pads are used and must characteristics such as high wear resistance, low weight, durability, low noise and stable friction coefficient. Polymer matrix, in addition to providing other material suitable for storage, the final properties, including mechanical properties, heat, friction and wear is also effective. Thermoset resin polymer matrixes (usually phenolic resin) are used in the brake pads which used for automotive and in some cases, rubber particles as powder formulations may be entered, in order to achieve good properties of rubber and resin simultaneously. Nanofillers because of...
Investigation on the Role of Curing System on the Cure Kinetics and Network Structure of NR/SBR Blend Filled with Nanodiamond
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor)
Abstract
Vulcanization is one the most crucial process in elastomer manufacturing products. It has been shown that network structure and curing kinetic are strongly dependent on curing system formulation. In addition reinforcing fillers in elastomers can affect them as well. By commencement of nanofillers in rubber domain, effects of nanofiller presence on rubber behavior have been investigated by reaserchers.
In this Project the effect of different curing system formulations on vulcanization kinetic and network structure of NR/SBR elastomeric matrice filled by nanodiamond is investigated. Different ingredients and nanodiamond were added to matrix by mechanical mixing in two roll mill. The...
In this Project the effect of different curing system formulations on vulcanization kinetic and network structure of NR/SBR elastomeric matrice filled by nanodiamond is investigated. Different ingredients and nanodiamond were added to matrix by mechanical mixing in two roll mill. The...
Preparation and Characterization of Morphology and Mechanical Properties of PA6/Nanodiamond Composites
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor)
Abstract
Polyamide or Nylon, due to its remarkable mechanical and tribological properties, has many engineering applications. Hence, improving the properties can develop the polyamide applications. In this study, Polyamide 6 (PA6) has been used as matrix with nanodiamond (ND) reinforcement. Spherical shape, chemically active surface as well as remarkable mechanical properties make nanodiamond an ideal candidate for improving polymers properties. Poor dispersion and agglomeration are present however major problems in achieving improved properties in nanocomposites. To deal with this problem, nanodiamonds were surface modified using Ethylenediamine (EDA) and Hexamethylenediamine (HMD). Nanocomposite...
Effect of chemical treatment of Teflon powder on the properties of polyamide 66/Teflon composites prepared by melt mixing
, Article Macromolecular Research ; Volume 19, Issue 6 , June , 2011 , Pages 613-621 ; 15985032 (ISSN) ; Gholamalipour, S ; Sharif University of Technology
2011
Abstract
The surface defluorination of Teflon in powdery form was performed using a chemical treatment. The reaction parameters including the reaction time, sodium, naphthalene concentrations were optimized using a Taguchi method to obtain maximum functionality on the particles surface. The surface functionality of the treated particles was analyzed by FTIR, energy dispersive X-ray analysis (EDX) and surface energy. Both treated (g-PTFE) and untreated (PTFE) Teflon were added to polyamide 66 (PA66) at various loadings up to 6 wt%. Mechanical, differential scanning calorimetry (DSC) and tribological analyses for different PA66/Teflon composites were carried out. The chemical treatment enhanced the...