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Experimental Investigation on the Effects of Angle of Attack on Supersonic Intake

, M.Sc. Thesis Sharif University of Technology Mostoufi, Keivan (Author) ; Soltani, Mohammad Reza (Supervisor)

Abstract

Twin intake is a new version of intakes for supersonic fighters with high performance. Investigations on these types of intakes show that with some modifications in design procedure and modifying the desired parameters, one could result in an intake compatible with the body and nose of the fighter with high efficiency. In this investigation the results of experiments on a supersonic air intake which is designed for 1.7 Mach number at angles of attack ranging from -4 to +6 degrees are presented. The main goal of this investigation is to analyze the effect of angle of attack on the performance of the intake in design and off-design conditions. In order to reduce the boundary layer thickness...

Powder metallurgical fabrication and characterization of nanostructured porous NiTi shape-memory alloy

, Article Materials and Manufacturing Processes ; Volume 21, Issue 8 , 2006 , Pages 727-735 ; 10426914 (ISSN) Sadrnezhaad, Kh ; Arami, H ; Keivan, H ; Khalifezadeh, R ; Sharif University of Technology

2006

Abstract

Production of NiTi alloy from elemental powders was conducted by mechanical alloying (MA) and sintering of the raw materials. Effects of milling time and milling speed (RPM) on crystallite size, lattice strain, and XRD peak intensities were investigated by X-ray analysis of the alloy. Powder compaction and sintering time and temperature effects on pore percentage of the as-mixed and the mechanically alloyed samples were empirically evaluated. The crystallite size of the mechanically alloyed Ni50Ti50 samples decreased with MA duration and with the milling speed. Depending on the crystal structure of the raw materials, the lattice strain increases with the milling duration. Metallographic...

Monitoring the Influence of Variations in Remotely-Sensed Values of Sea Surface Temperature Along with the El Niño Phenomenon on the Coral Reefs Bleaching, Case Study: Kish Island, Persian Gulf

, M.Sc. Thesis Sharif University of Technology Shabani, Fatemeh (Author) ; Raie, Mohammad (Supervisor) ; Kabiri, Keivan (Co-Supervisor)

Abstract

Coral reefs are one of the most important ecosystems in terms of animal diversity and affect the life of organisms in different ways. This ecosystem is under many stresses today. Among the most important events that threaten corals is the event of coral bleaching, the most important cause of which is the increase in Sea Surface Temperature (SST). Therefore, it is highly important to monitor changes in SST affecting corals. Generally, temperature anomalies are investigated using the Degree Heating Weeks index (DHW) and SST data. DHW index is variable in different coral areas and changes with time. Consequently, in the present study, this index has been investigated due to the lack of...

A multi-sender multicast algorithm for media streaming on peer-to-peer networks

, Article Computer Communications ; Volume 30, Issue 10 , July , 2007 , Pages 2191-2200 Firooz, M. H ; Ronasi, K. (Keivan) ; Pakravan, M. R. (Mohammad Reza) ; Nasiri Avanaki, A. (Alireza) ; Sharif University of Technology

2007

Abstract

Unlike those on Internet, the media providers on P2P networks are ordinary nodes with limited shared resources such as bandwidth. Multi-sender methods are the best existing solutions to video streaming on P2P networks. In this paper, we propose use of a multicast method on the top of an arbitrary multi-sender method so that all requesting peers receive almost the same expected bit-rate. Experimental results, derived from implementation of the proposed algorithm on Pastry P2P network confirm our claim. Another advantage of our method over the existing methods is its scalability with the number of receivers

2-D Bone Structure Prediction of Proximal Femur and Dominant Joint Load Estimation using Level Set Method and Bone RemodelingTheories

, M.Sc. Thesis Sharif University of Technology Keivan Bahari, Mahsa (Author) ; Farahmand, Farzam (Supervisor) ; Movahhedy, Mohammad Reza (Supervisor) ; Rouhi, Gholamreza (Co-Advisor)

Abstract

Bones adapt their form and structure to make an efficient use of their mass against the applied mechanical loads. So, it is not surprising to assume that the geometry and density distribution of a bone contains information about its loading history. The objective of this work was to develop a framework to simulate the bone remodeling procedure as a topology optimization process and then use this framework to develop a simple technique for estimating the dominant joint loads based on the bone’s density distribution.
At first, the remodeling equation was derived from the structural optimization task of minimizing the strain energy in each time step, using the level set method. Employment...