Smulation of Hydrogen Production by the Process of Thermal Decomposition of Methane

, M.Sc. Thesis Sharif University of Technology Parishan, Samira (Author) ; Saboohi, Yadollah (Supervisor)

Abstract

Different disadvantages associated with using fossil fuels as the main energy source including crisis of wells’ depletion and serious environmental problems, causing by the emission of large quantities of greenhouse gases (GHG), especially carbon dioxide (CO2), has increased attention to replacing them with renewable and clean fuels such as wind, solar, and geothermal energy sources. Hydrogen, as a clean energy carrier, is one of the best fuels in terms of the environment and cost. So, it is recently receiving increasing attention and it may one day replace fossil fuels for various applications such as in automobiles and power stations. The main subject of this thesis was surveying the...

The Calculation of Margin Requirements For Gold Futures Contracts By Using Conditional Extreme Value Theory

, M.Sc. Thesis Sharif University of Technology Karimi, Samira Mameghani (Author) ; Zamani, Shiva (Supervisor)

Abstract

Futures exchanges require a margin requirement that ensures their competitiveness and protects against default risk. The purpose of a margin requirement is to protect a clearinghouse from members’ defaults resulting from big losses due to adverse movement of futures prices. Extreme movements are central to the margin setting problem, because only a large price variation may cause brokers to incur losses. So in this study according to recent default in gold futures in Iran Mercantile Exchange we apply extreme value theory for computing unconditional and conditional optimal margin levels based on Block-Maxima and Peak over threshold approaches.The results show that at very high confidence...

Laboratory Study of Transverse Dispersion and Hydrodynamic of Continuous Flow Around Cylindrical Cylinders

, M.Sc. Thesis Sharif University of Technology Soltani, Samira Sadat (Author) ; Jamali, Mirmosadegh (Supervisor)

Abstract

In this study, by performing a series of experiments, the effect of the presence of cylinders on the formation of vortices and the interaction of cylinders on each other and, finally, transverse propagation in a steady flow are investigated. The cylinder cylinders that are in the direction of the motion of the water, have a significant effect on the hydrodynamic aspects and propagation in these streams. In the pattern of flow around cylindrical cylinders, with increasing Reynolds number, the vortex behind the stem begins to oscillate and when they reach, vortices flow into the stream. The flow velocity field, the formation and vortex fluctuation, affects the process of particle propagation...

An applicable count rate saturation correction approach on gamma camera for I-131 labeled radiopharmaceuticals

, Article Results in Physics ; Volume 12 , 2019 , Pages 1901-1904 ; 22113797 (ISSN) Haghighatafshar, M ; Piruzan, E ; Entezarmahdi, S. M ; Shekoohi Shooli, F ; Parishan, M. R ; Sharif University of Technology

Elsevier B.V 2019

Abstract

Background: Gamma camera count rate saturation and high-rate dead time are the most important problems of quantitative measurement in dosimetric studies. In this study, we aimed to assess an algorithm for correction of the measured counting rates in the entire energy spectrum (327–400 keV) for camera dead-time effects. Methods: In our study, whole body (WB) scan was performed by using a tissue-equivalent phantom, and that the radioactive Iodine (I-131) source with activities of 0.3, 0.6, 1.2, 1.5, 2.07, 2.7, 3.7, and 5.55 GBq was applied. WB scans of the 20% width energy windows were acquired for 420 s. Results: Camera dead-time parameters were obtained from different activities of I-131 in...

Nanoparticle-based optical sensor arrays

, Article Nanoscale ; v. 9 , 2017 , pages 16546 – 16563 ; 2040-3364 Hormozi-Nezhad, M. R ; Bigdeli, Arafeh ; Ghasemi, Forough ; Golmohammadi, Hamed ; Abbasi-Moayed, Samira ; Farahmand Nejad, M. Amin ; Fahimi-Kashani, Nafiseh ; Jafarinejad, Somayeh ; Shahrajabian, Maryam ; Sharif University of Technology

Royal Society of Chemistry 2017

Abstract

As in many other methods that have integrated nanoparticles (NPs), the chemical nose/tongue strategy has also progressed greatly since the entrance of NPs into this field. The fascinating tunable physicochemical properties of NPs have made them powerful candidates for array-based sensing platforms and have enabled the development of real-time, sensitive and portable systems that are able to target complex mixtures of analytes. In particular, the unique optical properties of NPs have a key role in providing promising array-based sensing approaches. This review will describe the main aspects and processes of most common NP-based optical sensor arrays. The fundamental steps in the design of a...