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Using ARB Process for Metal Matrix Foam and Composite Production
, M.Sc. Thesis Sharif University of Technology ; Akbarzadeh, Abbas (Supervisor)
Abstract
Metal matrix composites (MMC) and metal foams (MF) have been the topic of numerous researches during the last decades. The appropriate mechanical and physical properties of these materials make them useful in various industries. In this research, a unique approach is introduced for producing MMCs and MFs in which accumulative roll bonding (ARB) is employed in order to achieve a homogeneous distribution of ceramic particles in the metal matrix. Also, foamed structures can be made by subjecting Al/TiH2 composite to an appropriate annealing heat treatment where TiH2 particles decompose to hydrogen and titanium. In this work, the effect of number of ARB cycles on the size and distribution of...
Designing a collaborative digital library to improve educational systems accompanied by a perspective from Iranian scholar attitudes
, Article International Conference on Enterprise Information Systems and Web Technologies 2010, EISWT 2010, 12 July 2010 through 14 July 2010 ; 2010 , Pages 132-140 ; 9781617820656 (ISBN) ; Firouz Abadi, A. D ; Khalkhali, I ; Shafiei, M. S ; Vojdanijahromi, R ; Sharif University of Technology
2010
Abstract
In this article, a universal collaborative and competitive approach is introduced for deployment of digital collections in an ideal Digital Library for future's educational system. A hierarchical structure is proposed to be used for browsing and searching within mass of digital contents provided for union of curriculums worldwide. The collaborative and open-source aspects of the system guarantee the growth of the Digital Library. On the other hand, the competitive and reviewing aspects guarantee the accuracy of the novel library contents. Two experiments confirm the need for such a universal Digital Library worldwide to enhance learning capabilities, increase accessibility, avoid redundancy...
Multi-objective optimization of a projectile tip for normal penetration
, Article International Journal of Engineering, Transactions A: Basics ; Volume 26, Issue 10 , 2013 , Pages 1225-1234 ; 10252495 (ISSN) ; Roshanfekr, S ; Toraabi, M ; Sharif University of Technology
2013
Abstract
The main purpose of the present work is multi-objective shape optimization of a projectile tip for impacting and normal penetrating. Velocity drop, weight and inner volume of projectile have been considered as three conflicting objective functions. For this purpose, at the first step, finite element modeling was done using ABAQUS/Explicit and projectile penetration was examined in different geometric dimensions. Hammersley sequence sampling was employed for designing computer experiments. In the next step, results of the FEM were employed as raw data for MLF-type neural network training to achieve a mathematical model which is able to describe velocity drop behavior. Projectile weight and...
CFM: A file manager with multiple categorization support
, Article SEKE 2010 - Proceedings of the 22nd International Conference on Software Engineering and Knowledge Engineering, 1 July 2010 through 3 July 2010 ; 2010 , Pages 748-751 ; 1891706268 (ISBN); 9781891706264 (ISBN) ; Afzali, H ; Khalkhali, I ; Delcheh, M. A ; Shafiei, M. S ; Mahdavi, M ; Sharif University of Technology
2010
Abstract
This paper introduces a new file manager to support multiple categorization. The proposed file manager is designed based on a subtle idea named Conceptual File Management (CFM). According to this approach, files are not contained by folders; nevertheless, each file can be a member of one or more folders (concepts). A prototype file manager is designed and implemented based on the new approach. Filtering by set operations and also manual concept selection improves retrieval of the files. CFM improves file system's clarity and avoids ambiguity and redundancy. As a result, it reduces the size of file system and enhances file access
Improvement of Dynamic Modeling and Control of Single-axis Two wheeled Vehicle
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Gholamreza (Supervisor)
Abstract
In the recnt decades, traffics and airpolution are the most impoetant concerns of researchers in the field of city transportation. One of the most successful ways to overcome these poblems is to ustilize two-wheeled, one axis balancing vehicles. These vehicles occupies a small sapace, consumes less energy and its considerable maneuverability, makes it the best option to reform in-city transportation system. The newly introduced model of these robots incorporates a passenger cabin and a strick to control its movement. Unfortunately, in all of the recent studies, robots dynamics and controller system are base on optimistic hypothesis, which is no slippage between ground and wheels. Even in the...
Web Anomaly Host Based IDS, a Machine Learning Approach
, M.Sc. Thesis Sharif University of Technology ; Azmi, Reza (Supervisor) ; Khansari, Mohammad (Co-Advisor)
Abstract
Web servers and web applications are susceptible to different attacks. In order to detect web-based attacks Intrusion detection systems (IDS) should be equipped with a large number of signatures. Unfortunately various types of web threats are increasingly growing and so detection and prevention of all these new and old attacks is exhaustive and really difficult.This thesis represents a designed system for intrusion detection that uses different techniques to discover vulnerabilities with derived patterns and also some user behavior based attacks against web applications. This was done by using new dataset which was generated by new log file.The primary objective of this thesis shows the...
Semi analytical prediction of automobile body temperature distribution in the top coat paint oven
, Article Proceedings of the ASME Summer Heat Transfer Conference 2009, HT2009, 19 July 2009 through 23 July 2009 ; Volume 3 , 2009 , Pages 655-660 ; 9780791843581 (ISBN) ; Sajadi, B ; Saidi, M. H ; Khalkhali, H ; Taherraftar, M ; Sharif University of Technology
2009
Abstract
Automotive industry frequently needs to test new products, according to different production parameters, in order to determine the actual thermal behavior of bodies before mass production is implemented. Numerical simulation of these processes can reduce the very expensive and time consuming experimental procedures. For the drying and hardening process of the top paint applied in the coating process, the body temperature must be raised according to the paint manufacturer regulations. Consequently, prediction of temperature distribution of the car body during various zones of ovens is very vital in the design and performance analysis of the paint dryers. In this research, a novel...
FTS: An efficient tree structure based tool for searching in large data sets
, Article ICIME 2010 - 2010 2nd IEEE International Conference on Information Management and Engineering, 16 April 2010 through 18 April 2010 ; Volume 2 , April , 2010 , Pages 294-298 ; 9781424452644 (ISBN) ; Najafpour, M ; Mahdavi, M ; Ashurzad Delcheh, M ; Khalkhali, I ; Sharif University of Technology
2010
Abstract
This paper addresses the issue of finding and accessing desired items when a large amount of data items are concerned, by proposing some concepts based on Tree Search Structure -a hierarchical structure for information retrieval. The proposed concepts are applicable to several environments such as File Managers on PCs, help tree views, site maps, taxonomies, and cell phones. A software tool, FTS (File Tree Search), that is developed to utilize the proposed concepts is also presented
A reliability study of the new sensors for movement analysis (SHARIF-HMIS)
, Article Journal of Bodywork and Movement Therapies ; Volume 20, Issue 2 , 2016 , Pages 341-345 ; 13608592 (ISSN) ; Dehghan Manshadi, F ; Khalkhali Zavieh, M ; Ashouri, S ; Azimi, H ; Parnanpour, M ; Sharif University of Technology
Churchill Livingstone
2016
Abstract
Aim: SHARIF-HMIS is a new inertial sensor designed for movement analysis. The aim of the present study was to assess the inter-tester and intra-tester reliability of some kinematic parameters in different lumbar motions making use of this sensor. Materials and methods: 24 healthy persons and 28 patients with low back pain participated in the current reliability study. The test was performed in five different lumbar motions consisting of lumbar flexion in 0, 15, and 30° in the right and left directions. For measuring inter-tester reliability, all the tests were carried out twice on the same day separately by two physiotherapists. Intra-tester reliability was assessed by reproducing the tests...
Collaborative digital library: enhancing digital collections to improve learning in educational programs
, Article Proceeding JCDL '09 Proceedings of the 9th ACM/IEEE-CS joint conference on Digital libraries Pages 359-360 ; 2009 , Pages 359- 360 ; 15525996 (ISSN); 9781605586977 (ISBN) ; Dehghani Firouzabadi, A ; Khalkhali, I ; Afzali, H. R ; Ashurzad Delcheh, M ; Shoja Shafiei, M ; Alipour, M ; ACM SIGWEB; ACM SIGIR; IEEE CS ; Sharif University of Technology
2009
Abstract
In this article, a universal collaborative and competitive approach is introduced for deployment of digital collections in an ideal Digital Library (DL) for future's educational system. The collaborative and open-source aspects of the system guarantee its growth and the competitive aspects guarantee the accuracy
Intelligent semi-active vibration control of eleven degrees of freedom suspension system using magnetorheological dampers
, Article Journal of Mechanical Science and Technology ; Volume 26, Issue 2 , 2012 , Pages 323-334 ; 1738494X (ISSN) ; Sarrafan, A ; Khayyat, A. A. A ; Zabihollah, A ; Sharif University of Technology
2012
Abstract
A novel intelligent semi-active control system for an eleven degrees of freedom passenger car's suspension system using magnetorheological (MR) damper with neuro-fuzzy (NF) control strategy to enhance desired suspension performance is proposed. In comparison with earlier studies, an improvement in problem modeling is made. The proposed method consists of two parts: a fuzzy control strategy to establish an efficient controller to improve ride comfort and road handling (RCH) and an inverse mapping model to estimate the force needed for a semi-active damper. The fuzzy logic rules are extracted based on Sugeno inference engine. The inverse mapping model is based on an artificial neural network...
Performance and exhaust emission characteristics of a spark ignition engine operated with gasoline and CNG blend
, Article Proceedings of the Spring Technical Conference of the ASME Internal Combustion Engine Division ; 2012 , Pages 179-187 ; 15296598 (ISSN) ; 9780791844663 (ISBN) ; Hamidi, A. A ; Mozafari, A. A ; Sharif University of Technology
2012
Abstract
Using CNG as an additive for gasoline is a proper choice due to higher octane number of CNG enriched gasoline with respect to that of gasoline. As a result, it is possible to use gasoline with lower octane number in the engine. This would also mean the increase of compression ratio in SI engines resulting in higher performance and lower gasoline consumption. Over the years, the use of simulation codes to model the thermodynamic cycle of an internal combustion engine have developed tools for more efficient engine designs and fuel combustion. In this study, a thermodynamic cycle simulation of a conventional four-stroke spark-ignition engine has been developed. The model is used to study the...
A comparative study of the performance of a SI engine fuelled by natural gas as alternative fuel by thermodynamic simulation
, Article 2009 ASME Internal Combustion Engine Division Fall Technical Conference, ICEF 2009, Lucerne, 27 September 2009 through 30 September 2009 ; 2009 , Pages 49-57 ; 9780791843635 (ISBN) ; Hamidi, A. A ; Mozafari, A. A ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2009
Abstract
With the declining energy resources and increase of pollutant emissions, a great deal of efforts has been focused on the development of alternatives for fossil fuels. One of the promising alternative fuels to gasoline in the internal combustion engine is natural gas [1-5]. The application of natural gas in current internal combustion engines is realistic due to its many benefits. The higher thermal efficiency due to the higher octane value and lower exhaust emissions including CO2 as a result of the lower carbon to hydrogen ratio of the fuel are the two important feature of using CNG as an alternative fuel. It is well known that computer simulation codes are valuable economically as a cost...
Analytical and experimental analyses of nonlinear vibrations in a rotary inverted pendulum
, Article Nonlinear Dynamics ; Volume 107, Issue 3 , 2022 , Pages 1887-1902 ; 0924090X (ISSN) ; Pasharavesh, A ; Khayyat, A. A. A ; Sharif University of Technology
Springer Science and Business Media B.V
2022
Abstract
Gaining insight into possible vibratory responses of dynamical systems around their stable equilibria is an essential step, which must be taken before their design and application. The results of such a study can significantly help prevent instability in closed-loop stabilized systems by avoiding the excitation of the system in the neighborhood of its resonance. This paper investigates nonlinear oscillations of a rotary inverted pendulum (RIP) with a full-state feedback controller. Lagrange’s equations are employed to derive an accurate 2-DoF mathematical model, whose parameter values are extracted by both the measurement and 3D modeling of the real system components. Although the governing...
A suction-controlled ring device to measure the coefficient of lateral soil pressure in unsaturated soils
, Article Geotechnical Testing Journal ; Volume 44, Issue 1 , 2020 ; Garakani, A. A ; Golshani, A ; Mirzaii, A ; Sharif University of Technology
ASTM International
2020
Abstract
A suction-controlled ring device has been developed to continuously measure the coefficient of lateral soil pressure in deformable unsaturated soil samples from the at-rest to the active condition under application of increasing vertical pressure and controlled matric suction. The device incorporates a thin aluminum specimen ring equipped with horizontal strain gages for recording the lateral soil strains. In addition, a sensor recording water volume changes is utilized to continuously monitor the degree of saturation of the soil sample during tests. The matric suction within the soil texture is controlled using the axis translation technique. In order to verify the performance of the ring...
Gum tragacanth gels as a new supporting matrix for immobilization of whole-cell
, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 24, Issue 4 , 2005 , Pages 1-7 ; 10219986 (ISSN) ; Vaziri, A ; Seifkordi, A. A ; Kheirolomoom, A ; Sharif University of Technology
2005
Abstract
We introduce a new smooth, non-toxic, biocompatible method for cross-linking of gum tragacanth (GT), a polysaccharide of natural origin, in order to serve as a new supporting matrix for immobilization systems. The modified gum is used as a matrix for the catalysis of the conversion of benzyl penicillin to 6-aminopenicillanic acid (6-APA) by means of Escherichia coli ATCC11105 with penicillin G acylase (PGA) activity. The results show that GT beads can not only serve as a proper matrix for immobilization, but show enhanced hydrolysis rate and stability compared to other immobilization systems used for this reaction. This signifies the potential of GT as a biocompatible matrix for...
True Class-E Design For Inductive Coupling Wireless Power Transfer Applications
, Article 30th International Conference on Electrical Engineering, ICEE 2022, 17 May 2022 through 19 May 2022 ; 2022 , Pages 864-868 ; 9781665480871 (ISBN) ; Safarian, A ; Fotowat Ahmady, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
The Class-E power amplifier has been widely studied and formulated in the literature. Although the majority of reported inductive coupling wireless power transfer (WPT) systems use a class-E power amplifier for driving the primary coil, still there is a lack of a comprehensive study on class-E circuit dedicated to WPT, providing a set of closed form design equations for proper class-E operation. This paper presents the required design equations needed to design a 'true' class-E circuit for WPT applications. Equations for the series-tuned secondary coil WPT system are presented, as well as two different design procedures for the parallel-tuned secondary coil. The derived equations have been...
Crashworthiness determination of side doors and B pillar of a vehicle subjected to pole side impact
, Article Applied Mechanics and Materials ; Vol. 663, issue , 2014 , p. 552-556 ; Faieza, A. A ; Sahari, B. B ; Nuraini, A. A ; Halali, M ; Sharif University of Technology
2014
Abstract
Pole Side Impact Tes is one out of three crash tests described by Euro NCAP standard for star rating of a vehicle and is required for assessing the Adult Occupant Protection. In this paper the goal is to determine the crashworthiness of side doors and B pillar in a Pole Side Impact Test based on Euro New Car Assessment Program (Euro-NCAP) using computer and simulation method. In this matter, a vehicle model has been prepared and meshed using Hypermesh and CATIA. The velocity of 29 km/h has been assigned to the vehicle which was on top of a cart while the pole has been assigned as a rigid static object based on Euro NCAP requirements specifically. Results show that different amounts of energy...
Investigation of Thickness Influences On Energy Absorption For Side Doors And B Pillar In Euro NCAP Pole Side Impact Test
, Article Applied Mechanics and Materials ; Vol. 663, issue , Oct , 2014 , p. 585-589 ; Faieza, A. A ; Sahari, B. B ; Nuraini, A. A ; Halali, M ; Sharif University of Technology
2014
Abstract
To assess a car under the Euro New Car Assessment Program (Euro-NCAP), Adult Occupant Protection is one out of three parameters which need to be calculated with a weight factor of 50% while the other parameters, Child Occupant Protection and Pedestrian Occupant Protection, have a weight factor of 20%. The Pole Side Impact Test, beside two other tests, Side and Front Impact, is also required to calculate the Adult Occupant Protection. It shows how important the Pole Side Impact Test is and what an effective role it has in the car rating assessment. In this paper, the objective is to evaluate the effect of thickness on the energy absorbed by the side doors and the B pillar and its...
Crashworthiness determination for front and rear doors and B pillar subjected to side impact crash by a mobile deformable barrier
, Article Advanced Science Letters ; Volume 19, Issue 2 , 2013 , Pages 392-395 ; 19366612 (ISSN) ; Faieza, A. A ; Sahari, B. B ; Nuraini, A. A ; Halali, M ; Sharif University of Technology
2013
Abstract
In Euro NCAP standard, adult protection is one of the most important rating scores with 50% weight factor while child protection and pedestrian protection are accounted into consideration with 20% weight factor. For adult protection testing, three tests are required to perform: (1) side impact, (2) pole impact, (3) front impact. In the side impact test, dummy's head, chest, shoulder, thorax, ribs, abdomen, pelvic and femur must be studied to evaluate the rating score. Crashworthiness of a car during side impact can describe the score rated for that car. In this paper the goal is to determine the crashworthiness of side doors and B-pillar in side impact crash est by simulation using LS DYNA...