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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Diffusion of radom-222 in overburden and its application to uranium exploration

Soonawala, Noshirwan M. January 1976 (has links)
No description available.
52

Exploitations minières et politiques de gestion environnementale utilisation de l'expertise canadienne en fermeture de mines pour le site de l'ancienne mine d'uranium de l'INB à Caldas (Minas Gerais, Brésil) /

Peres Menezes, Mônica. Peres Menezes, Mônica. January 1900 (has links) (PDF)
Thèse (Ph. D. )--Université Laval, 2004. / Titre de l'écran-titre (visionné le 29 novembre 2004). Également présenté dans le cadre du doctorat de l'auteur: Gestion environnementale des parcs à résidus miniers : un défi pour l'avenir / film réalisé par Mônica Peres Menezes, Frédérick Dion et Samantha Merlin. Bibliogr.
53

Obtencao de hexafluoreto de uranio por oxidacao catalitica de tetrafluoreto de uranio

BRANDAO FILHO, DAVID 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:31:23Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:03Z (GMT). No. of bitstreams: 1 01399.pdf: 1423391 bytes, checksum: 08febe2724da4dfe4af1b47ac4c334b1 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
54

Obtencao de hexafluoreto de uranio por oxidacao catalitica de tetrafluoreto de uranio

BRANDAO FILHO, DAVID 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:31:23Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:03Z (GMT). No. of bitstreams: 1 01399.pdf: 1423391 bytes, checksum: 08febe2724da4dfe4af1b47ac4c334b1 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
55

Electrical, magnetic and thermal properties of uranium nickel(2) silicon(2) and uranium nickel(2) germanium(2).

Ning, Yuebin. Datars, W.R. Unknown Date (has links)
Thesis (Ph.D.)--McMaster University (Canada), 1991. / Source: Dissertation Abstracts International, Volume: 53-11, Section: B, page: 5794. Supervisor: W. R. Datars.
56

A uranium anomaly in the Silver Bell prospect, Sweetwater County, Wyoming

Monzon Cisneros, Felipe Gregorio, 1940-, Monzon Cisneros, Felipe Gregorio, 1940- January 1970 (has links)
No description available.
57

The process mineralogy of selected Southern African uranium ores

Youlton, Brandon 06 May 2015 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, December 2014. / During the acid leaching of uranium, gangue-reagent interactions have both negative and positive consequences. Gangue dissolution increases reagent costs, and in some cases can prevent the economic acid leaching of an ore, but can also increase uranium mineral exposure and improve recoveries. Due to rapid dissolution kinetics, the acid consumption characteristics of the various carbonate species are readily predicted, however the same is not true of silicate gangue. Due to factors including slower leach rates, incongruent dissolution, parabolic kinetics, and surface area, pH and temperature dependence, the gangue acid consumption characteristics of silicate minerals are significantly more complex. A detailed mineralogical investigation and acid leach tests were conducted on sandstone- and granite-hosted uranium ore samples. The dissolution characteristics of the more common gangue phases were determined. The study demonstrated that gangue-reagent interactions and U dissolution can be predicted from mineralogical data. A model was developed which allows for the use of mineralogical and geochemical data to predict gangue reagent consumption. The basic framework of the model is universally applicable, but may require calibration, depending on the mineral assemblage and complexity of a specific uranium deposit.
58

Density functional theory investigation of the uranium oxides

Brincat, Nick January 2015 (has links)
The aim of this thesis is to provide insight into the structures and properties of the uranium oxides. As UO2 is easily oxidised during the nuclear fuel cycle it is important to have a detailed understanding of the structures and properties of the oxidation products. Experimental work over the years has revealed many stable oxides including UO2, U4O9, U3O7, U2O5, U3O8 and UO3, all with a number of different polymorphs. The oxides are broadly split into two categories, fluorite-based structures with stoichiometries in the range of UO2 to U2O5 and less dense layered-type structures with stoichiometries in the range of U2O5 to UO3. While UO2 is well characterised, both experimentally and computationally, there is a paucity of data concerning higher stoichiometry oxides in the literature. Experiments and simulations are emerging that deal with individual phases, however a comprehensive study that assesses the properties of all polymorphs and provides comparison over the full range of stoichiometries has been lacking from the literature First the nuclear fuel cycle is introduced, as well as UO2 as a nuclear fuel (Chapter 1), before the quantum mechanical methodology used throughout is explained (Chapter 2). Applying a number of different density functionals (including GGAs, meta-GGAs and hybrids) to UO2 in Chapter 3 it emerges that the PBE + U formalism reproduces the experimentally observed properties to a good degree of accuracy, and so is selected for the rest of the simulations. Following this Chapter 4 examines defect clusters in UO2, finding split interstitials to dominate at low stoichiometry (UO2 – UO2.0625), chains of 2:2:2 Willis clusters at higher stoichiometry (UO2.125 – UO2.25 (U4O9)) and split quad interstitials at higher stoichiometry (UO2.33 (U3O7)). Chapter 5 is an investigation of layered U2O5, where it emerges that the Np2O5 structure is more stable than δ-U2O5 and all uranium ions are in the U5+ oxidation state. Next Chapter 6 considers layered U3O8, which is structurally oxygen rich U2O5, where it is found that U5+ and U6+ ions exist in pentagonal bipyramidal and octahedral coordination respectively. The final set of results in Chapter 7 concern the polymorphs of UO3, where it is found that U6+ adopts a range of coordination environments and the predicted relative stability of each modification matches well with experiment. Finally the conclusions are presented in Chapter 8 along with plans for future work.
59

Bimetallic actinide complexes for small molecule activation

Wells, Jordann Ashley Logan Slovenne Denis January 2018 (has links)
The work described in this thesis concerns the synthesis of actinide complexes and their reactivity towards small unsaturated molecules. Complexes bearing tetraphenoxide, borohydride and boroxide ligands have been evaluated. Additionally, work towards the synthesis of heterobimetallic uranium transition metal complexes and their applications in catalysis is discussed. Chapter one reviews important organoactinide complexes reported in the literature which effect chemical transformations on small unsaturated substrates. Actinide complexes supported by aryloxide or borohydride ligands are reviewed, along with actinide complexes in which metal p-arene interactions are present. Chapter two reports the synthesis and characterisation of a set of tetraphenol ligands, in addition to a number of attempted synthetic routes to tetraphenol ligands with alternate substitution. The chemistry of those tetradentate aryloxide ligands is introduced with bimetallic uranium(IV) and thorium(IV) complexes using different An(IV) and U(III) precursors. Chapter three reports the synthesis and characterisation of monometallic uranium and thorium complexes using a tetraphenol ligand. The varying chemistry between the two similar An(IV) ions, where the uranium complexes exist as a mixture of oligomers and the thorium complexes remain as well defined mononuclear complexes, is discussed within. A range of base adducts of mononuclear actinide complexes are reported, including a thorium trimethylsilylazide complex, a rare example of a metal organoazide. Chapter four describes the synthesis of homoleptic boroxide and heteroleptic borohydride complexes of uranium(III). The reactivities of these complexes with small unsaturated molecules are assessed, including the reaction of a low coordinate uranium(III) boroxide complex towards CO2 to provide a dinuclear uranium carbonate bridged complex. Chapter five introduces work towards heterobimetallic uranium transition metal complexes carried out in the Arnold group. The application of these complexes towards ring opening polymerisation chemistry is discussed in addition to investigations into the incorporation of transition metals into uranium(IV) complexes. Chapter Six presents the detailed experimental methods used to carry out this research.
60

Uranium series dating of bone and cave deposits

Rae, Angela Mottes January 1986 (has links)
No description available.

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