Study of Mechanism of Formation of Metal Oxide Nanoparticles in Supercritical Water Medium

, M.Sc. Thesis Sharif University of Technology Akhlaghpasand, Hamze (Author) ; Outokesh, Mohammad (Supervisor) ; Ahmadi, Javad (Co-Advisor)

Abstract

One of the most convenient methods for the synthesis of metal oxide nanoparticles, inorganic ceramic materials and catalysts is supercritical hydrothermal method. In its pure form or mixed metal oxide nanoparticles have potential applications are wide. An important aspect of functional metal oxides of uranium dioxide as the selective catalyst for the conversion of methane to methanol and chlorinated organic matter decomposition is used. The main issue that led to the definition of this project was that nanoparticles synthesized with supercritical hydrothermal conditions influenced by change in the temperature. Temperature also affects the particle size and the conversion efficiency. This...

Conversion of Methane into Heaviour Hydrocarbures using Nanosecond Lasers

, Ph.D. Dissertation Sharif University of Technology Navid Khoshgonab, Hamze Ali (Author) ; Sadighi Bonabi, Rasoul (Supervisor)

Abstract

In this thesis the conversion of methane into higher hydrocarbures using pulsed nanosecond lasers has been studied. The lasers of 532 nm of second harmonic of Nd: YAG, 355 nm of 3rd harmonic of Nd: YAG and 248 nm of KrF have been used in this project. Acetylene, ethylen and ethane have been detected using gas chromatography detection system, which showed acetylene as a dominant product. For each wavelength the amount of the laser energy and the fraction of secondary products have been measured. Also the dependence of amount of produced components on chamber pressure has been studied for 355 nm laser. During the irradiation time of methane no considerable changes in temperature and pressure...

Characterization of the ion beam current density of the rf ion source with flat and convex extraction systems

, Article Silicon ; Volume 10, Issue 6 , 2018 , Pages 2743-2749 ; 1876990X (ISSN) Salehi, M ; Zavarian, A. A ; Arman, A ; Hafezi, F ; Rad, G. A ; Mardani, M ; Hamze, K ; Luna, C ; Naderi, S ; Ahmadpourian, A ; Sharif University of Technology

Springer Netherlands 2018

Abstract

The characterization of ion beam current density distribution and beam uniformity is crucial for improving broad-beam ion source technologies. The design of the broad ion beam extraction system directly affects these two parameters, therefore, depending on the application, the design and geometry of the source is changed. In this study, the effect of the presence or the absence of a neutralization process on the ion beam density was investigated. Also, the effect of the probe bias on the ion beam current measurement was evaluated. Eventually, using a flat probe, the ion beam profiles obtained from the extraction system of the ion source (Model RFIS 60, ACECR, Iran) were measured at energies...