Recovery of Uranium(VI) from UCF Waste by Selective Transportacross Aliquid Membrane

, M.Sc. Thesis Sharif University of Technology Soltani Behrouz, Masoud (Author) ; Samadfam, Mohammad (Supervisor) ; Fasihi, Javad (Supervisor)

Abstract

Due to environmental and economical impacts, recovery of the uranium from nuclear wastes is of continuing interest.This work reports the separation of uranyl ionusing transport technique through chloroform liquid membrane containing a mixture of DBDA15C4 and oleic acidas cooperative carrier.The pH of the feed phase (10-4 M of UO22+) was adjusted with nitric acid and acetic acid/NaOH for pHrange of 2-6.The receiving phase was hydrochloric acid 1M.The organic phase was chloroform which includesthe carrier DBDA15C4 (0.0001 M) and also the oleic acid (0.015M).The results showed that the transport increased with increasing pH and reached to maximumat pH of 5.Maximum cooperative effect of oleic...

Water Quality Modeling of Urban Streams

, M.Sc. Thesis Sharif University of Technology Soltani, Maryam (Author) ; Tajrishy, Masoud (Supervisor)

Abstract

With altering natural state and increasing impervious surfaces, traditional urbanization leads to deteriorating the environment and water catchments. During the years most efforts in order to control the urban runoff outflow, have been focused on quantity; and awareness about improving water quality has been raised just in the last few years and, which emphasizes on pollution source control. Standard water quality sampling methods are time consuming, expensive and because of sampling in broad geographic areas, difficult; however modeling is a more efficient way in assessing water quality and as worries about non-point source pollution grows, different kinds of models have been used to...

Factors Affecting Index Funds Performance: The Case of Karafarin Index Fund

, M.Sc. Thesis Sharif University of Technology Soltani, Mehrdad (Author) ; Ebrahimnejad, Ali (Supervisor) ; Talebian, Masoud (Supervisor)

Abstract

Index funds are one of the most vital financial institutions providing a wide range of values for different investors. Despite the importance of these funds, not only are index funds recently developed, but they also do not replicate their indices effectively. In this paper, we analyze the portfolio performance of the Karafarin Index Fund as an open-end fund for case study in various frameworks. First of all, the asset allocation and security selection attributions are assessed for capturing the capabilities to choose the suitable security at the right time. In addition, this assessment is done for the industry allocation and security selection attribution in the stock portfolio of the...

Numerical simulation and parametric study of a supersonic intake

, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 227, Issue 3 , January , 2013 , Pages 467-479 ; 09544100 (ISSN) Soltani, M. R ; Younsi, J. S ; Farahani, M ; Masoud, A ; Sharif University of Technology

2013

Abstract

A computational fluid dynamics code was developed to compute the flow inside and around a supersonic external compression axisymmetric intake. The code solves the Reynolds-averaged Navier-Stokes equations using an explicit finite volume method in a structured grid and uses the Baldwin-Lomax algebraic model to compute the turbulent viscosity coefficient. Experiments were performed to validate the predicted results and good agreements are achieved. In the next part of the research, a parametric study was undertaken using the designed base case at a constant Mach number of 2 and at 0° angle of attack. The effects of various important parameters such as free stream Mach number, spike deflection...

A reconfigurable fault-tolerant routing algorithm to optimize the network-on-chip performance and latency in presence of intermittent and permanent faults

, Article Proceedings - IEEE International Conference on Computer Design: VLSI in Computers and Processors ; 2011 , Pages 433-434 ; 10636404 (ISSN) ; 9781457719523 (ISBN) Jabbarvand Behrouz, R ; Modarressi, M ; Sarbazi Azad, H ; Sharif University of Technology

2011

Abstract

As the semiconductor industry advances to the deep sub-micron and nano technology points, the on-chip components are more prone to the defects during manufacturing and faults during system operation. Consequently, fault tolerant techniques are essential to improve the yield of modern complex chips. We propose a fault-tolerant routing algorithm that keeps the negative effect of faulty components on the NoC power and performance as low as possible. Targeting intermittent faults, we achieve fault tolerance by employing a simple and fast mechanism composed of two processes: NoC monitoring and route adaption. Experimental results show the effectiveness of the proposed technique, in that it offers...

Dynamic Modeling and Congestion Control in Computer Networks

, M.Sc. Thesis Sharif University of Technology Kahe, Ghasem (Author) ; Jahangir, Amir Hossein (Supervisor) ; Ebrahim, Behrouz (Co-Advisor)

Abstract

Active queue management (AQM) is a key factor in congestion control and should provide appropriate feedback for flow control in traffic sources to overcome the congestion problem. Beside providing congestion control, achieving predictable queuing delay, maximizing link utilization, simplicity and robustness are also the main objectives of an AQM controller. We propose in this thesis an improved queue dynamic model while incorporating the packet drop probability as well. The proposed model is evaluated using ns2 platform. By applying the improved model, a new compensated proportionalintegral- derivative (PID) AQM controller is developed for TCP network. The time-varying nature of the network...

Determination of Optimum Material and Thickness of Filter Based on Radiation Energy in Digital Industrial Radiography (CR) Using MCNP Monte Carlo Simulation Code

, M.Sc. Thesis Sharif University of Technology Haghizadeh, Cyrus (Author) ; Vosoughi, Naser (Supervisor) ; Rokrok, Behrouz (Supervisor) ; Movafeghi, Amir (Co-Supervisor)

Abstract

In this study, the effect of external filter on the various parameters of image quality in digital industrial radiography by CR method for steel and aluminum piece has been investigated. The filter reduces the noise of scattered beams by absorbing the low-energy beams in the X-ray spectrum that are most likely to be scattered, but high filter thicknesses can attenuate the more energetic beams and have a negatively effect on the image quality. On the other hand, the absorption of those low-energy beams increases the average spectrum energy and thus reduce the contrast, so it is necessary to use the appropriate material and thickness of the filter. For this purpose, to examine the filter...

Deployment of multi-agent robotic systems in presence of obstacles

, Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010, Istanbul ; Volume 5 , 2010 , Pages 7-12 ; 9780791849194 (ISBN) Soltani, A ; Sayyaadi, H ; Sharif University of Technology

2010

Abstract

The deployment of multi-agent systems in presence of obstacle deals with autonomous motion of agents toward a specified target by sensing each other and boundaries of obstacles. In this paper, asynchronous, scalable, distributed algorithm is used to deploy agents. Boundaries of obstacles are modeled by virtual agents. Algorithm was implemented by solving continuous n-median problem called generalized Fermat-Weber problem. It is shown that deployment is performed when position of real agents are the geometric median of their Voronoi cells. Simulation results show the validity of the proposed algorithm very well

Enforcing access control policies over data stored on untrusted server

, Article 2017 14th International ISC (Iranian Society of Cryptology) Conference on Information Security and Cryptology, ISCISC 2017, 6 September 2017 through 7 September 2017 ; 2018 , Pages 54-57 ; 9781538665602 (ISBN) Soltani, N ; Jalili, R ; Sharif University of Technology

2018

Abstract

One of the security issues in data outsourcing scenario is the enforcement of data owner's access control policies. This includes some challenges; namely, the number of keys required to access authorized resources, efficient policy updating, write access control enforcement, user and data owner overhead, and preserving confidentiality of data and policies. Most of the existing solutions address only some of the challenges, while they impose high overhead on both the data owner and users. Though, policy management in the Role-Based Access Control (RBAC) model is easier and more efficient due to the existence of role hierarchical structure and role inheritance; most of the existing solutions...

Experimental investigation of unsteady wake behind a section of a wind turbine blade

, Article 25th AIAA Applied Aerodynamics Conference, 2007, Miami, FL, 25 June 2007 through 28 June 2007 ; Volume 2 , 2007 , Pages 870-876 ; 10485953 (ISSN) ; 1563478986 (ISBN); 9781563478987 (ISBN) Soltani, M.R ; Mahmoudi, M ; Sharif University of Technology

2007

Abstract

A series of experiments were carried out to study the unsteady wake phenomenon behind an oscillating airfoil. The airfoil is a section of a wind turbine blade oscillating in pitch about the quarter chord axis at various reduced frequencies, oscillation amplitude and mean angles of attack. Streamwise velocity profiles were obtained by real time and instantaneous measurements at 35 vertically aligned points behind the airfoil via two similar rakes. One of rakes has only static pressure probes and the other is equipped with total pressure ones. An estimation of the variation of linear momentum defect during the oscillation is obtained and has been compared with the corresponding static one. The...

Structural Health Monitoring of composite Plates with Piezoelectric WaferActive Sensors

, M.Sc. Thesis Sharif University of Technology Soltani, Zahra (Author) ; Abedian, Ali (Supervisor)

Abstract

Cost-effective and reliable damage detection is critical for utilization of composite materials. This research investigates a wavelet-based approach for SHM and detection of through-thickness crack in different lengths and angles in [0/45/-45/90]s CF/EP composite plate utilizing ANSYS finite element method (FEM) software and digital signal processing technique utilizing MATLAB software. To this end, a dual-PZT actuation scheme is applied, aimed at generating the S0 mode at a square composite plate. This study contributes to the damage detection by developing an improved wavelet-based signal processing technique that enhances the visibility and interpretation of the Lamb wave signals related...

Compressive Response of Cylindrical Concrete Columns Confined with Steel Spirals and GFRP Composites

, M.Sc. Thesis Sharif University of Technology Soltani, Hesam (Author) ; Khalu, Alireza (Supervisor)

Abstract

Concrete structures require reinforcement and retrofitting because of possible mistakes in design or calculation, inconformity between plan and implementation, change in occupancy or applied loads, and decay. Development in technology, production of materials, and new methods play important roles in development of structure construction and reinforcement methods. Emerge of new materials creates great demand in studying, surveying, and determining design characteristic and criteria for these materials. One of these materials is FRP composite which is used in concrete structure reinforcement in different ways. In this laboratory research, the effect of external wrapping by GFRP composite...

Enforcing Access Control Policies over Data Stored on Untrusted Server

, M.Sc. Thesis Sharif University of Technology Soltani, Naeimeh (Author) ; Jalili, Rasoul (Supervisor)

Abstract

Recently many organizations outsource their data to an external server due to easier data maintenance. One of the security issues in data outsourcing scenario is the enforcement of data owner’s access control policies. This includes some challenges; namely, the number of keys needed to access authorized resources, efficient policy updating, write access control enforcement, user and data owner overhead, and preserving confidentiality of data and policies . Most of the existing proposed solutions address only some of these challenges, while they impose high overhead on both the data owner and users. Moreover, most of them address enfrocement of policies in form of access control matrix and...

Synthesis, Characterization and Photocatalytic Application of ZnO/g- C3N4 Composite Nanorods Fabricated by Combined Sol Gel-Hydrothermal Methods

, M.Sc. Thesis Sharif University of Technology Soltani, Mojtaba (Author) ; Moshfegh, Alireza (Supervisor)

Abstract

Because of the working conditions of semiconductors at ambient temperature and pressure, degradation of organic pollutants through semiconductors photocatalysis has attracted the interest of many researchers. Because of its large exciton binding energy,high chemical and physical stability,high electron and hole mobility, and low cost; zinc oxide, an n-type semiconductor with 3.2 eV direct band gap, is widely used in applications such as photocatalysts, solar cells, and light-emitting diodes. Among various morphologies of ZnO, 1D nanostructures such as nanowires and nanorods have recieved much attention due to their high surface to volume ratio. However, the application of ZnO as a...

A Protocol to Improve Privacy and Security of Anonymity Networks

, M.Sc. Thesis Sharif University of Technology Soltani, Mahdi (Author) ; Jalili, Rasool (Supervisor)

Abstract

In recent two decades, different anonymous communication systems has been proposed. These systems are interested by journalists, bank employees, military forces, and human rights advocates. Tor is one of the most popular anonymous communication systems. Tor uses onion routing for privacy preserving. Re-cently, many attacks has been introduced against the anonymity of Tor users.In these attacks entry and exit nodes are compromised. One of these malicious nodes, makes the attack on the intented flow and the other one recognizes the flow. All these attacks admit their vulnerability against dummy messages. They state that, because of dynamics of onion’s keys, any dummy injection will dis-turb...

Design and Simulation (& Manufacturing) of A Micro-Gyroscope

, M.Sc. Thesis Sharif University of Technology Soltani, Arman (Author) ; Akbari, Javad (Supervisor)

Abstract

Nowadays, microgyroscopes are among the most important products of MEMS. The production of small, precise and inexpensive gyroscopes has become possible as the result of recent developments in fabrication technology. In this thesis it is intended to introduce a new method for manufacturing more precise microgyroscopes regarding manufacture facilities. Using this new method, sensitivity and resistance of microgyroscopes are increased against noises which are primarily caused by vibration and rotation about undesirable axes. The rotational movement imposed on the gyro is detected through fluid flow within its torus channel. This transformation facilitates the measurement of the initial motion....

Control Algorithm of Multi-agent Systems in Special Paths With an Applied Consideration in Biomechanical Engineering to Perform Operations of Interior Treatments

, M.Sc. Thesis Sharif University of Technology Soltani, Ali (Author) ; Sayyadi, Hassan (Supervisor)

Abstract

In this project Deployment of multi-agent systems was studied. Maximum coverage over a point or curve or area is desired in deployment of multi-agent systems. A facility location optimization function was derived from geometrical concepts such as voronoi, n- geometric median and fermat-weber problem by optimization of which the deployment of multi-agent systems is performed. First, it is assumed that dynamic of agents is first order and second order .Next, it is assumed that agents are in a fluid. In all situations a suitable control algorithm was derived to optimize the facility location function to perform deployment. Next, another facility location function was derived by optimization...

Secure Transmission Strategies in Massive MIMO Systems in Presense of a Jammer

, M.Sc. Thesis Sharif University of Technology Soltani, Marziyeh (Author) ; Mirmohseni, Mahtab (Supervisor)

Abstract

Massive MIMO systems are systems, where the base station has many number of antenna so each user’s channel is orthogonal to one another.These systems have some valuable advantages such as reduction of energy needed for transmission and significant improvement in spectral efficiency, which makes them be suitable for next generation of wireless communication systems. Another advantage of Massive MIMO systems is inherent resistance against passive eavsdroppers due to having a directed power radiation in direction of the desired user. However another physical layer attack threat these systems: attacking in pilot phase then eavsdropping in downlink phase which must taken care of in physical...

Dynamic Performance Enhancement of RC Slabs by Steel Fibers vs. Externally Bonded GFRP Sheets under Impact Loading

, Ph.D. Dissertation Sharif University of Technology Soltani, Hesam (Author) ; Khaloo, Alireza (Supervisor)

Abstract

Recently, to improve the dynamic behavior of Reinforced Concrete (RC) slabs under impact load, the methods of externally bonding Glass Fiber Reinforced Polymer (GFRP) sheets to slab and internally reinforcing concrete by steel fibers have been proposed. Nevertheless, it is required to investigate the comparison between these two methods on response of RC slabs under impact loads. In this study, the influence of volume fraction of steel fibers, the number of GFRP sheet layers (one or two) and the arrangement of GFRP sheets (covering the whole or parts of surface), are examined. Performance of fourteen mm concrete slabs including one plain slab, one steel RC slab, three steel RC slabs...

Control of a Distributed Multi-agent System of Quadrotors for Transportation of a Shared Load

, Ph.D. Dissertation Sharif University of Technology Soltani, Ali (Author) ; Sayyadi, Hassan (Supervisor)

Abstract

Nowadays, multi-agent robotic systems are implemented to perform various operations such as military mission, search and rescue operations, etc. One of the most interested robotic platforms for multi-agent systems is quadrotor aerial robot. In this paper, a team of quadrotors is prepared to perform a formation flight toward a specified target in order to catch and transport it on a desired path. Therefore, at first, trajectory tracking control of the quadrotor has been studied and two types of controllers have been introduced: Hierarchical controller and Non-hierarchical controller. Coordinate free structure of the hierarchical controller provides distinctive properties and guarantees...