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Removal of Fluorine from radioactive solid waste of Esfahan Uranium Conversion Facility
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Khanchi, Alireza (Supervisor) ; Gasemi, Hosein (Co-Advisor)
Abstract
Uranium is the most important element in the nuclear fuel cycle. Recovery of uranium from waste produced at every stage of the fuel cycle is not only economically important, but also environmentally important. In the production phase of uranium hexafluoride, certain amount of solid waste is produced in the bottom of the fluorination reactor. In order to extract the uranium from this waste, we have to eliminate the fluorine contained in the waste. This is because the fluorine forms strong complex with uranyl ions during the extraction process, and prevents from efficient extraction of uranium. In the current thesis؛ first, we examined the characteristics of the waste ...
Uranium Recovery from Solid Waste of Flourination Reactor of UCF Plant
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Ghaemi, Ahad (Supervisor) ; Ghasemi, Mohammad Reza (Co-Advisor)
Abstract
Uranium is one of the most important elements in nuclear fuel cycle. Recovery of uranium from wastes that were generated in varrious prosesses of nuclear fuel cycle, is very important not only because of economical values, but also due to their envirolmental. A considerable amount of solid waste have been produced during the fluorination process of in fluorination fludizedbed reactor at UCF plant in Iran. In this thesis, first, the solid waste of UCF floinatin reactor has been characterized. After characterization of waste, the dissolution of waste by different solvents has been studied and optimom condition for dissolution was determinated. Uranium recovery from the solution was tested...
Optimization of Municipal Solid Waste Management According to Regional Solid Waste Characterization
, M.Sc. Thesis Sharif University of Technology ; Akbari Jokar, Mohammad Reza (Supervisor)
Abstract
Significant growth in the amount of municipal solid waste generated around the world has turned this phenomenon into a potential crisis in the future. At the same time, applying the right management policies will turn municipal waste into a sustainable source of large-scale revenue generation. With the increasing importance of data in managers' decisions, valuable data have been generated in various fields. One of these data is characterization of municipal solid waste, which should be considered as the first step in determining the policies of an integrated municipal solid waste management system. This paper presents a mixed integer programming model based on two-commodity network flow...
Development of a new workflow for pseudo-component generation of reservoir fluid detailed analysis: A gas condensate case study
, Article International Journal of Oil, Gas and Coal Technology ; Vol. 7, Issue. 3 , 2014 , pp. 275-297 ; ISSN: 1753-3317 ; Pishvaie, M. R ; Ghotbi, C ; Mittermeir, G. M ; Sharif University of Technology
Abstract
In this work, a new automatic workflow for accurate optimal pseudo-component generation from gas condensate mixtures with a large number of components is presented. This workflow has a good insight into thermo-physical and critical properties and introduces only a small amount of loss of information and EOS flexibility. In this regard, the fuzzy clustering is used to classify the components in the mixture based on the similarities in the critical properties. The mixing rules are then applied to find group properties. Two different approaches for components association in clustering process are investigated with several numbers of groups. The mathematical validity of the groups is controlled...
Influence of hydrogen reduction on growth of tungsten oxide nanowires
, Article Journal of Experimental Nanoscience ; Volume 7, Issue 6 , 2012 , Pages 597-607 ; 17458080 (ISSN) ; Khosravi, P ; Moshfegh, A. Z ; Sharif University of Technology
2012
Abstract
A simple method for synthesising W17O47 nanowires on tungsten oxide thin films deposited by sol-gel method on mica substrate has been reported. After thermally annealing thin films at 700 C in H2 ambient for different durations and subsequently in N2 ambient for 60 min, single-crystalline W17O47 nanowires along h0 01i direction were formed on the surface. Experimental results revealed that annealing under H2 ambient has an important effect on the growth of W17O47 nanowires. According to scanning electron microscopic observations, the synthesised nanowires have ∼70 nm in width and a few microns in length after annealing under H2 ambient for 30min and subsequently under N2 ambient for 60min. A...
Microstructural characterisation of deformation behaviour of nickel base superalloy IN625
, Article Materials Science and Technology ; Volume 27, Issue 12 , 2011 , Pages 1858-1862 ; 02670836 (ISSN) ; Asgari, S ; Sharif University of Technology
Abstract
Simple compression and microscopy techniques were employed to characterise the microstructural origin of the deformation behaviour of nickel base superalloy IN625 during large strain testing. The alloy exhibited a four-stage strain hardening response similar to that previously reported for low stacking fault energy face centred cubic alloys. At strains lower than about -0.06 (stage A), a falling regime of the hardening rate was observed. This stage was followed by a second stage (stage B) of slow increasing hardening rate, which was found to be coincident with the formation of Lomer-Cottrell locks. The second falling regime of strain hardening (stage C) was seen in the strain range of -0.25...
Enhanced corrosion resistance of porous NiTi with plasma sprayed alumina coating
, Article Corrosion Engineering Science and Technology ; Volume 50, Issue 8 , 2015 , Pages 595-600 ; 1478422X (ISSN) ; Akbarinia, S ; Mohammadyani, D ; Sadrnezhaad, S. K ; Sharif University of Technology
Maney Publishing
2015
Abstract
In this study, corrosion behaviour of porous NiTi modified by plasma sprayed alumina coating has been investigated. Scanning electron microscopy and X-ray diffraction techniques were applied for the morphology and microstructure characterisation, while linear sweep voltammetry and electrochemical impedance spectroscopy were used for investigation of corrosion behaviour of coated and uncoated NiTi specimens. Induced couple plasma was conducted to measure ion release of the specimens in simulated body fluid at 37°C. The plasma sprayed Al2O3 coating on the porous NiTi improved the surface characteristics for biomedical applications. The alumina coating significantly hampered Ni ion release from...
Fabrication and characterisation of ultrafine-grained Al-5vol%Al 2O3 nanocomposite
, Article International Journal of Nanomanufacturing ; Volume 5, Issue 3-4 , 2010 , Pages 341-351 ; 17469392 (ISSN) ; Simchi, A ; Seyed Reihani, S. M ; Simancik, F ; Sharif University of Technology
Abstract
Nanocrystalline Al-5vol%Al2O3 nanocomposite was synthesised by mechanical milling of a mixture containing nanometric alumina with an average particle size of 35 nm. Morphology of as-synthesised powder was investigated by SEM while crystallite size of Al matrix was determined by XRD analysis. The results confirmed formation of nanocrystalline Al matrix induced by severe plastic deformation during mechanical milling. Nanocomposite bars were produced by hot powder extrusion route. TEM investigation of as-extruded nanocomposite revealed formation of elongated grains along the extrusion direction decorated by alumina nanoparticles. Tensile and compressive properties of as-extruded nanocomposite...
Electrodeposition of Ni-WndashB nanocomposite from tartrate electrolyte as alternative to chromium plating
, Article Surface Engineering ; Volume 25, Issue 5 , 2009 , Pages 382-388 ; 02670844 (ISSN) ; Abdolmaleki, M ; Seyed Sadjadi, S. A ; Raghibi Boroujeni, M ; Arshadi, M. R ; Khoshvaght, H ; Sharif University of Technology
2009
Abstract
The effect of the bath chemistry and operating conditions on the chemical composition, microstructure and properties of NiWmdashB alloys deposited from tartrate baths on working electrode was studied for the first time by the pulsed current method. The investigations included the measurement of the current efficiencies and determination of the tungsten content in the electrodeposits. UV spectrometry was used for characterisation of complex formation. The grain size of deposits was determined by XRD. Also, the morphology of the deposits was studied by SEM. Amorphous NimdashWB alloys were successfully obtained by electrodeposition from the tartrate bath. The corrosion behaviour of NiWmdashB...
Synthesis and characterisation of nanosized TiO2-ZrO2 binary system prepared by an aqueous sol-gel process: Physical and sensing properties
, Article Sensors and Actuators, B: Chemical ; Volume 155, Issue 2 , July , 2011 , Pages 568-576 ; 09254005 (ISSN) ; Fray, D. J ; Sharif University of Technology
2011
Abstract
Nanostructured TiO2-ZrO2 thin films and powders were prepared by a straightforward aqueous particulate sol-gel route. Titanium (IV) isopropoxide and zirconium (IV) acetate hydrate were used as precursors, and hydroxypropyl cellulose was used as a polymeric fugitive agent in order to increase the specific surface area. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy revealed that the powder were crystallised at the low temperature of 500 °C, containing anatase-TiO 2 and tetragonal-ZrO2 phases. Furthermore, it was found that ZrO2 retarded the anatase-to-rutile transformation up to 900 °C. The activation energies for crystallite growth of TiO2 and ZrO2 components in...
Synthesis and characterisation of nanostructured neodymium titanium oxides by sol-gel process: Controlling the phase composition, crystal structure and grain size
, Article Materials Chemistry and Physics ; Volume 122, Issue 2-3 , 2010 , Pages 512-523 ; 02540584 (ISSN) ; Fray, D. J ; Sharif University of Technology
2010
Abstract
Nanocrystalline neodymium titanium oxide thin films and powders with different phase compositions with mesoporous structure were produced by a straightforward particulate sol-gel route. The sols were prepared in various Nd:Ti molar ratios and they showed a narrow particle size distribution in the range 20-26 nm. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the powders contained mixtures of Nd4Ti9O24, Nd2Ti4O11, Nd3Ti4O12 for titanium dominant powders (Nd:Ti ≤ 45:60), mixtures of Nd2TiO5 and Nd2O3 for neodymium dominant powders (Nd:Ti ≥ 75:25) and pure Nd3Ti4O12 phase for equal molar ratio of Nd:Ti, depending on the annealing temperature and Nd:Ti...