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University of Nevada, Las Vegas

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Articles 31 - 35 of 35

Full-Text Articles in Mineral Physics

Magnetic Ordering Phase Transitions Of Gd2sn2o7, Gordon Tam, Andrew Cornelius, Daniel Antonio Aug 2008

Magnetic Ordering Phase Transitions Of Gd2sn2o7, Gordon Tam, Andrew Cornelius, Daniel Antonio

Undergraduate Research Opportunities Program (UROP)

Pyrochlores with magnetic rare earth ions are a topic of interest due to unusual results brought about by their high degree of geometrical frustration. The lattice structure prevents the magnetic spin interactions from finding a single minimum energy state, which leads to a nonzero residual entropy[1]. By analyzing the heat capacity at low temperatures, the type of magnetic interaction can be determined and the temperatures at which long-range magnetic ordering and magnetic field induced splitting of energy states occur.


Modeling The Deformation Of Fayalite, Greg Hoth, Mike Brawner, Pamela Burnley Aug 2008

Modeling The Deformation Of Fayalite, Greg Hoth, Mike Brawner, Pamela Burnley

Undergraduate Research Opportunities Program (UROP)

We are studying how the mineral fayalite deforms under stress while it is subject to high pressures and temperatures. Specifically, we are analyzing x-ray diffraction spectra obtained from experiments with the D-DIA apparatus at Brookhaven national labs. By fitting peaks to the diffraction spectra, we can calculate the spacing between lattice planes of fayalite and so we can observe how this spacing changes over time as the crystal structure deforms We hope to show that this deformation can be modeled using an Elastic Plastic Self Consistent model. In such a model, the material is treated as a cluster of independently …


A New Method Of Synthesizing Black Birnessite Nanoparticles: From Brown To Black Birnessite With Nanostructures, Shizhi Qian, Marcos A. Cheney, Pradip K. Bhowmik, Sang W. Joo, Wensheng Hou, Joseph M. Okoh Jan 2008

A New Method Of Synthesizing Black Birnessite Nanoparticles: From Brown To Black Birnessite With Nanostructures, Shizhi Qian, Marcos A. Cheney, Pradip K. Bhowmik, Sang W. Joo, Wensheng Hou, Joseph M. Okoh

Mechanical Engineering Faculty Research

A new method for preparing black birnessite nanoparticles is introduced. The initial synthesis process resembles the classical McKenzie method of preparing brown birnessite except for slower cooling and closing the system from the ambient air. Subsequent process, including wet-aging at 7◦C for 48 hours, overnight freezing, and lyophilization, is shown to convert the brown birnessite into black birnessite with complex nanomorphology with folded sheets and spirals. Characterization of the product is performed by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TGA), and N2 adsorption (BET) techniques. Wet-aging and lyophilization times are shown to …


Thermochronological Evolution Of Calcite Formation At The Potential Yucca Mountain Repository Site, Nevada: Part 2 Fluid Inclusion Analyses And Upb Dating, Jean S. Cline, Amy J. Smiecinski, Robert Bodnar May 2002

Thermochronological Evolution Of Calcite Formation At The Potential Yucca Mountain Repository Site, Nevada: Part 2 Fluid Inclusion Analyses And Upb Dating, Jean S. Cline, Amy J. Smiecinski, Robert Bodnar

Publications (YM)

The presence of two-phase fluid inclusions in thin secondary mineral crusts at the potential Yucca Mountain nuclear waste repository has raised questions regarding the origin, timing, and temperature of past fluid flow through the repository horizon. The geologically recent passage of fluids with high temperatures would call into question the suitability of the site for the storage of high level nuclear waste. This study determined the thermal history of fluid flow through the site using fluid inclusion analyses and constrained the timing of thermal fluids by dating silica minerals spatially associated with the fluid inclusions using U-Pb techniques. Results provide …


Thermochronological Evolution Of Calcite Formation At The Proposed Yucca Mountain Repository Site, Nevada: Part 1, Secondary Mineral Paragenesis And Geochemistry, Jean S. Cline, Amy J. Smiecinski, Robert Bodnar May 2002

Thermochronological Evolution Of Calcite Formation At The Proposed Yucca Mountain Repository Site, Nevada: Part 1, Secondary Mineral Paragenesis And Geochemistry, Jean S. Cline, Amy J. Smiecinski, Robert Bodnar

Publications (YM)

In the near future a decision will be made as to whether or not Yucca Mountain, 90 miles northwest of Las Vegas, Nevada is a suitable site for a permanent, underground, high level nuclear waste repository. A major factor in determining the suitability of Yucca Mountain as a repository is the potential for the site to be flooded by water during the regulatory lifetime. The current study was undertaken to examine the past fluid history at the site, to gain a better understanding of the possibility of flooding in the near geologic future. To estimate the past fluid flux into …