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in subjects: "Vanadates"

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Multivariate statistical analysis of stream sediments for mineral resources from the Craig NTMS Quadrangle, Colorado

Multivariate statistical analyses were carried out on Hydrogeochemical and Stream Sediment Reconnaissance data from the Craig quadrangle, Colorado, to support the National Uranium Resource Evaluation and to evaluate strategic or other important commercial mineral resources. A few areas for favorable uranium mineralization are suggested for parts of the Wyoming Basin, Park Range, and Gore Range. Six potential source rocks for uranium are postulated based on factor score mapping. Vanadium in stre… more

Date: June 1, 1980

Creator: Beyth, M.; McInteer, C.; Broxton, D. E.; Bolivar, S. L. & Luke, M. E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Coupled electron-nuclear magnetism and neutron diffraction. [PrSn/sub 3/; HoVO/sub 4/; PrCu/sub 2/]

It often occurs that, in a rare-earth compound having a singlet electronic ground state, a long-range magnetically ordered state is formed by coupling of the nuclear spins with the electrons through the hyperfine interaction, at millikelvin temperatures. Neutron scattering has been used to measure the details of the magnetization processes of both the electrons and the nuclear spins in the coupled state in PrSn/sub 3/, HoVO/sub 4/, and PrCu/sub 2/. The polarized nuclear spins could be observed … more

Date: July 1, 1985

Creator: Kawarazaki, S. & Arthur, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Colorimetric determination of Fe sup 2+ /Fe sup 3+ ratio in radioactive glasses

In the vitrification of nuclear wastes, the Fe{sup 2+}/Fe{sup 3+} ratio in the glass is a measure of the redox properties of the glass melt. It is necessary to measure this ratio to ensure that the melt redox properties are suitable for the glass melter. A colorimetric method for measuring the Fe{sup 2+}/Fe{sup 3+} ratio in highly radioactive glasses was developed and tested remotely in a shielded cell. The tests were performed on glasses similar in composition and radioactivity to those that w… more

Date: January 1, 1992

Creator: Coleman, C. J.; Baumann, E. W. & Bibler, N. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Lithium Insertion Chemistry of Some Iron Vanadates

Lithium insertion into various iron vanadates has been investigated. Fe{sub 2}V{sub 4}O{sub 13} and Fe{sub 4}(V{sub 2}O{sub 7}){sub 3} {center_dot} 3H{sub 2}O have discharge capacities approaching 200 mAh/g above 2.0 V vs. Li{sup +}/Li. Although the potential profiles change significantly between the first and subsequent discharges, capacity retention is unexpectedly good. Other phases, structurally related to FeVO{sub 4}, containing copper and/or sodium ions were also studied. One of these, {b… more

Date: February 2, 2007

Creator: Patoux, Sebastien & Richardson, Thomas J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Use of DWPF redox measurement technique on glasses from West Valley Nuclear Fuel Services Demonstration Project

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass in the Defense Waste Processing Facility (DWPF). A similar vitrification facility exists at the West Valley Nuclear Fuel Services. In both of these facilities, control of the oxidation/reduction (redox) equilibrium in the glass melter is critical for processing of the nuclear waste. Redox can be determined by measuring the ratio of ferrous to ferric ions in the glass melt.… more

Date: October 1, 1990

Creator: Jantzen, Carol M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Histopathologic, morphometric, and physiologic investigation of lungs of dogs exposed to uranium-ore dust

The most consistent pulmonary-function change attributed to carnotite uranium-ore-dust exposure (at 15 mg/m/sup 3/, for 4 h/day, 5 days/week) is an increased slope of the single-breath N/sub 2/ washout curve, suggesting an uneven distribution of ventilation. This change was observed in dogs exposed for less than 1 year and continued through 4 years of exposure. Measurements of pulmonary resistance, after 27, 40 and 47 months exposure, showed slight age-related changes and increasing differences… more

Date: January 1, 1981

Creator: Cross, F. T.; Filipy, R. E.; Loscutoff, S. M.; Mihalko, P. J.; Palmer, R. F. & Busch, R. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Report of Foreign Research Assignment for M. M. Abraham, October 1989-September 1990

The traveler collaborated with M.J.M. Leask, J.M. Baker, B. Bleaney, and others at the Clarendon Laboratory, Oxford University, Oxford, UK, to Study Tetragonal rare-earth phosphates and vanadates by optical and magnetic spectroscopy. This work is related to similar studies that have been performed at ORNL by the Synthesis and Properties of Novel Materials Group in the Solid State Division.

Date: October 15, 1990

Creator: Abraham, M. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Colorimetric determination of Fe{sup 2+}/Fe{sup 3+} ratio in radioactive glasses

Date: May 1, 1992

Creator: Coleman, C. J.; Baumann, E. W. & Bibler, N. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

New ytterbium-doped apatite crystals for flexible laser design

A new class of Yb-lasers is summarized in this article. The apatite family of crystals has been found to impose favorable spectroscopic and laser properties on the Yb{sup 3+} activator ion. Crystals of Yb-doped Ca{sub 5}(PO{sub 4}){sub 3}F, Sr{sub 5}(PO{sub 4}){sub 3}F, Ca{sub x}Sr{sub 5{minus}x}(PO{sub 4}){sub 3}F, and Sr{sub 5}(VO{sub 4}){sub 3}F have been grown and investigated. Several useful laser crystals have been identified which offer a variety of fundamental laser parameters for desig… more

Date: March 1, 1994

Creator: Payne, S. A.; DeLoach, L. D.; Smith, L. K.; Krupke, W. F.; Chai, B. H. T. & Loutts, G.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Anomalous temperature dependence of the lattice parameters in HoPO{sub 4} and HoVO{sub 4}: Rare earth quadrupolar effects

The temperature dependence of the lattice parameters in tetragonal HoPO{sub 4} and HoVO{sub 4} was measured using neutron powder-diffraction techniques. Below about 100K, the lattice parameter a of HoPO{sub 4} increases with decreasing temperature while c decreases. In HoVO{sub 4}, the above behavior is reversed, that is, a decreases with decreasing temperature while c increases. Similar measurements on nonmagnetic LUP0{sub 4} and LuVO{sub 4} do not show any anomaly. This observation indicates … more

Date: July 1, 1994

Creator: Skanthakumar, S.; Loong, C. K.; Soderholm, L.; Nipko, J.; Richardson, J. W. Jr.; Abraham, M. M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Impermeable Thin Al2O3 Overlay for TBC Protection From Sulfate and Vanadate Attack in Gas Turbines Quarterly Report

To improve the hot corrosion resistance of YSZ thermal barrier coatings, a 25 {micro}m thick Al{sub 2}O{sub 3} overlay were deposited by HVOF thermal spray, respectively, onto to the surface of YSZ coating. In the next reporting period, we will measure or calculate the residue stress within Al{sub 2}O{sub 3} overlay and YSZ coating to study the mechanism of effect of Al{sub 2}O{sub 3} overlay on spalling of YSZ coating. However, due to the thermal expansion mismatch between YSZ coating and Al{s… more

Date: March 31, 2004

Creator: Mao, Scott X.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Impermeable Thin Al2O3 Overlay for TBC Protection From Sulfate and Vanadate Attack in Gas Turbines Quarterly Report

To improve the hot corrosion resistance of YSZ thermal barrier coatings, a 25 {micro}m and a 2 {micro}m thick Al{sub 2}O{sub 3} overlay were deposited by HVOF thermal spray and by sol-gel coating method, respectively, onto to the surface of YSZ coating. Indenter test was employed to investigate the spalling of YSZ with and without Al{sub 2}O{sub 3} overlay after hot corrosion. The results showed that Al{sub 2}O{sub 3} overlay acted as a barrier against the infiltration of the molten salt into t… more

Date: December 16, 2003

Creator: Mao, Scott X.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Impermeable thin AI2O3 overlay for TBC protection from sulfate and vanadate attack in gas turbines

25 {micro}m and a 2 {micro}m thick Al{sub 2}O{sub 3} overlay were deposited by HVOF thermal spray and by sol-gel coating method, respectively, onto to the surface of YSZ coating. Indenter test was employed to investigate the spalling of YSZ with and without Al{sub 2}O{sub 3} overlay after hot corrosion. The results showed that Al{sub 2}O{sub 3} overlay acted as a barrier against the infiltration of the molten salt into the YSZ coating during exposure, thus significantly reduced the amount of M-… more

Date: January 31, 2005

Creator: Mao, Scott X.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Impermeable Thin Al2O3 Overlay for TBC Protection From Sulfate and Vanadate Attack in Gas Turbines Quarterly Report

Date: December 16, 2003

Creator: Mao, Scott X.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Impermeable thin AI2O3 overlay for TBC protection from sulfate and vanadate attack in gas turbines

{alpha} - Al{sub 2}O{sub 3} overlay has been deposited on the YSZ surface by the composite-sol-gel route (CSG). Hot corrosion tests were carried out on the TBCs with and without Al{sub 2}O{sub 3} coating in molten salt mixtures (Na{sub 2}SO{sub 4} + 5%V{sub 2}O{sub 5}). The results showed that besides a thin and dense alumina overlay with the thickness of about 100-500 nm formed on the YSZ surface, the microcracks and porous near the surface in YSZ was also occupied by alumina because of penetr… more

Date: April 30, 2005

Creator: Mao, Scott X.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Impermeable Thin Al2O3 Overlay for TBC Protection From Sulfate and Vanadate Attack in Gas Turbines Quarterly Report

In order to improve the hot corrosion resistance of conventional YSZ TBC system, a thin and dense {alpha}-Al{sub 2}O{sub 3} overlay has been deposited on the YSZ surface by the composite-sol-gel route (CSG). The YSZ substrates were dipped with boehmite sol containing calcined {alpha}-Al{sub 2}O{sub 3} particles, dried to form a gel film and calcined at 1200 C to form {alpha}-Al{sub 2}O{sub 3} overlay. Hot corrosion tests were carried out on the TBCs with and without Al{sub 2}O{sub 3} coating in… more

Date: March 10, 2003

Creator: Mao, Scott X.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

IMPERMEABLE THIN AL2O3 OVERLAY FOR TBC PROTECTION FROM SULFATE AND VANADATE ATTACK IN GAS TURBINES

The project started on September 1, 2001. During last 4 months, one post-doctor has been hired for this project. We have received TBC samples (YSZ/CoNiCrAlY/ Inconel 601) from Tohoku University, Japan, while processing of the TBC samples was delayed in GE Corp. Research and Development. The TBC preparation in Japan was based on our technical requirement by plasma spray. Bond coat CoNiCrAlY and the YSZ was produced by low-pressure plasma spray and air plasma spray respectively. The morphology of… more

Date: January 31, 2002

Creator: Mao, Scott X.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Impermeable Thin Al2O3 Overlay for TBC Protection From Sulfate and Vanadate Attack in Gas Turbines Quarterly Report

To improve the hot corrosion resistance of YSZ thermal barrier coatings, a 25 {micro}m and a 2 {micro}m thick Al{sub 2}O{sub 3} overlay were deposited by HVOF thermal spray onto to the surface of YSZ coating. Oxidation at high temperature and hot corrosion tests showed that Al{sub 2}O{sub 3} overlay deposited on the YSZ TBCs surface can not only reduce the hot corrosion rate, but also significantly prevents the bond coat from oxidation.

Date: August 31, 2004

Creator: Mao, Scott X.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

IMPERMEABLE THIN AL2O3 OVERLAY FOR TBC PROTECTION FROM SULFATE AND VANADATE ATTACK IN GAS TURBINES

In order to improve the hot corrosion resistance of conventional YSZ TBC system, a dense and continues overlay of Al{sub 2}O{sub 3} coating of about 25 {micro}m thick was deposited on the surface of TBC by EB-PVD and high velocity oxy-fuel (HVOF) spray techniques. Hot corrosion tests were carried out on the TBC with and without Al{sub 2}O{sub 3} coating in molten salts mixtures (Na{sub 2}SO{sub 4} + 5% V{sub 2}O5) at 950 C for 10h. The microstructures of TBC and overlay before and after exposur… more

Date: August 31, 2002

Creator: Mao, Scott X.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

IMPERMEABLE THIN AL2O3 OVERLAY FOR TBC PROTECTION FROM SULFATE AND VANADATE ATTACK IN GAS TURBINES

In order to improve the hot corrosion resistance of conventional YSZ TBC system, the overlay of Al{sub 2}O{sub 3} coating was deposited on the TBC by EB-PVD techniques. Hot corrosion tests were carried out on the TBC with and without Al{sub 2}O{sub 3} coating in molten salts mixtures (Na{sub 2}SO{sub 4} + 5%V{sub 2}O{sub 5}) at 950 C for different time up to 100h. The microstructures of TBC and overlay before and after exposure were examined by means of scanning electron microscopy (SEM), energ… more

Date: August 31, 2002

Creator: Mao, Scott X.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

IMPERMEABLE THIN Al2O3 OVERLAY FOR TBC PROTECTION FROM SULFATE AND VANADATE ATTACK IN GAS TURBINES

In order to improve the hot corrosion resistance of conventional YSZ TBC system, the Al{sub 2}O{sub 3} overlay coating has been successfully produced on the surface of YSZ by the Sol-gel route. The YSZ substrates were coated with boehmite sol by dip coating process, dried to form a gel film and calcined at 1200 C to form {alpha}-Al{sub 2}O{sub 3} overlay. The microstructures of TBC and Al{sub 2}O{sub 3} overlay were examined by scanning electron microscopy (SEM). The results showed that micro-p… more

Date: November 30, 2002

Creator: Mao, Scott X.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Impermeable Thin Al2O3 Overlay for TBC Protection From Sulfate and Vanadate Attack in Gas Turbines Quarterly Report

In order to improve the hot corrosion resistance of yttria-stabilized zirconia (YSZ), an Al{sub 2}O{sub 3} overlay has been deposited on the surface of YSZ by electron-beam physical vapor deposition. Currently, hot corrosion tests were performed on the YSZ coatings with and without Al{sub 2}O{sub 3} overlay in molten salt mixture (Na{sub 2}SO{sub 4} + 0 {approx} 15wt%V{sub 2}O{sub 5}) at 950 C in order to investigate the effect of amount of vanadate on the hot corrosion behaviors. The results s… more

Date: June 10, 2003

Creator: Mao, Scott X.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Deposition and Characterization of Highly Oriented Mg(3)(VO(4))(2) Thin Film Catalyst

Magnesium vanadates are potentially important catalytic materials for the conversion of alkanes to alkenes via oxidative dehydrogenation. However, little is known about the active sites at which the catalytic reactions take place. It may be possible to obtain a significant increase in the catalytic efficiency if the effects of certain material properties on the surface reactions could be quantified and optimized through the use of appropriate preparation techniques. Given that surface reactivit… more

Date: October 22, 1999

Creator: Rodriguez, Mark A.; Ruffner, Judith A.; Sault, Allen G. & Tissot, Ralph G., Jr.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The chemical potential from extrinsic ions in oxide films on aluminum

X-ray studies of Cr in Al oxide films have shown that 3- and 6-valent Cr may be present. 300 nm Al films were anodized, cathodized or exposed to K{sub 3}Cr(CN){sub 6}, NaMoO{sub 4}, KMnO{sub 4}, or NaVO{sub 3} solutions. Cathodized surfaces were then anodized in borate solution. X-ray absorption at glancing angle and fluorescence detection were used to study species incorporated in the oxide surface. The 3-valent Cr present was closely related to Cr(OH){sub 3}. Absence of a pre-edge peak associ… more

Date: January 1, 1992

Creator: Isaacs, H. S. & Davenport, A. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department