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razmi--fereshteh
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Improving Defensive Techniques Against Malwares
, M.Sc. Thesis Sharif University of Technology ; Kharrazi, Mehdi (Supervisor)
Abstract
Advances in computing and networking areas lead to advent of malwares with new and sophisticated features. One of these type of malwares are environment sensitive malwares which behave differently when finding out specific signs in the execution environment. They first was considered and defined in the context of malware analysis systems; meaning that these types of malwares stop their malicious behavior when detecting analysis machine as their execution environment. In this way they could challenge and evade analysis process. Afterwards, the domain of environment sensitive malwares went beyond the analysis systems and covered all environmental sensitivities which hinder the progress of...
Experimental and numerical approach to enlargement and determination of performance of primary sedimentation basin
, Article 2007 5th Joint ASME/JSME Fluids Engineering Summer Conference, FEDSM 2007, San Diego, CA, 30 July 2007 through 2 August 2007 ; Volume 2 FORA, Issue PART A , March , 2007 , Pages 265-272 ; 0791842886 (ISBN); 9780791842881 (ISBN) ; Firoozabadi, B ; Sharif University of Technology
2007
Abstract
In the present study, the presence of a baffle and its effect on the hydrodynamics of the flow in a primary settling tank has been investigated experimentally by ADV (Acoustic Doppler Velocimeter). On the other hand, the characteristics of this flow field were simulated by an unsteady two-phase finite volume method, and VOF (Volume of Fluid) model; and results were evaluated by the experimental data. The numerical calculation performed by using k - ε RNG model agrees well with experiments. It depicts the ability of this method in predicting the velocity profile and flow structure. In addition, the optimum position of the baffle to achieve the best performance of the tank was determined by...
Experimental and numerical approach to enlargement of performance of primary settling tanks
, Article Journal of Applied Fluid Mechanics ; Volume 2, Issue 1 , 2009 , Pages 1-12 ; 17353572 (ISSN) ; Firoozabadi, B ; Ahmadi, G ; Sharif University of Technology
2009
Abstract
Circulation regions always exist in settling tanks. These regions would result in short-circuiting enlargement of the dead zone and high flow mixing problems and avoid optimal particle sedimentation. Therefore, the main objective of the tank design process is to avoid formation of the circulation zone, which is known as dead zone. Experiments show that the tank performance can be improved by altering the geometry of the tank which leads to a different velocity distributions and flow patterns. In this paper, the presence of a baffle and its effect on the hydrodynamics of the flow field has been investigated in a primary settling tank. Hydrodynamics of the flow field in these basins is...
Investigation of hydrogen sensing properties and aging effects of Schottky like Pd/porous Si
, Article Journal of Sensors and Actuators B: Chemical ; Volume 146, Issue 1 , 8 April , 2010 , PP. 53–60 ; Iraji Zad, A. (Azam) ; Rahimi, F. (Fereshteh) ; Sharif University of Technology
2010
Abstract
We prepared porous silicon samples coated by continuous palladium layer in electroless process. Scanning electron microscopy (SEM) showed cauliflower-shape Pd clusters on the surface. I–V curves of Schottky like Pd/porous Si samples were measured in air and in hydrogen. These measurements showed a metal–interface–semiconductor configuration rather than an ideal Schottky diode. Variations of the electrical current in the presence of diluted hydrogen at room temperature revealed that the samples can sense hydrogen in a wide range of concentration (100–40,000 ppm) without any saturation behavior. Hydrogen sensing properties of these samples were investigated at room temperature for a duration...
Experiments and numerical modeling of baffle configuration effects on the performance of sedimentation tanks
, Article Canadian Journal of Civil Engineering ; Volume 40, Issue 2 , 2013 , Pages 140-150 ; 03151468 (ISSN) ; Bakhtyar, R ; Firoozabadi, B ; Barry, D. A ; Sharif University of Technology
2013
Abstract
The hydraulic efficiency of sedimentation basins is reduced by short-circuiting, circulation zones and bottom particleladen jets. Baffles are used to improve the sediment tank performance. In this study, laboratory experiments were used to examine the hydrodynamics of several baffle configurations. An accompanying numerical analysis was performed based on the 2-D Reynolds-averaged Navier-Stokes equations along with the k-ε turbulence closure model. The numerical model was supplemented with the volume-of-fluid technique, and the advection-diffusion equation to simulate the dynamics of particle-laden flow. Model predictions compared well with the experimental data. An empirical function was...
Energy, exergy, and economic analyses of an innovative energy storage system; liquid air energy storage (LAES) combined with high-temperature thermal energy storage (HTES)
, Article Energy Conversion and Management ; Volume 226 , 15 December , 2020 ; Zeynalian, M ; Razmi, A. R ; Arabkoohsar, A ; Soltani, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Liquid air energy storage is one of the most recent technologies introduced for grid-scale energy storage. As the title implies, this technology offers energy storage through an air liquefaction process. High energy storage density, no geographical limitation, and applicability for large-scale uses are some of the advantages of this technology. To improve the performance and environmental friendliness of the conventional design of this technology, a novel liquid air energy system combined with high-temperature thermal energy storage, thermoelectric generator, and organic Rankine cycle is proposed in the present article. The thermal energy storage unit removes the need for the conventional...
Computational Investigation of Bubble-Shock Wave Interaction, Using Front Tracking-Ghost Fluid Method
, M.Sc. Thesis Sharif University of Technology ; Taeibi Rahni, Mohammad (Supervisor) ; Massah, Hamid Reza (Co-Supervisor)
Abstract
Shock wave–bubble interaction is not yet fully understood, while has many important applications. Such physics for example appears in sonoluminescense phenomenon, wherein a sinusoidal pressure field causes a gas bubble to first become large and then small enough to collapse. In this complex physics, spherical shock wave also appears right before, during, and right after the bubble bursting. On the other hand, modeling the interface between the liquid and gas in such problems, in which the gas becomes compressible is challenging. In this regard, Ghost-Fluid/Front Tracking method has shown to be very practical. In this work, the Euler equations have been computationally solved to simulate the...