230Th-234U Age-Dating Uranium by Mass Spectrometry (open access)

230Th-234U Age-Dating Uranium by Mass Spectrometry

This is the standard operating procedure used by the Isotope Ratio Mass Spectrometry Group of the Chemical Sciences Division at LLNL for the preparation of a sample of uranium oxide or uranium metal for {sup 230}Th-{sup 234}U age-dating. The method described here includes the dissolution of a sample of uranium oxide or uranium metal, preparation of a secondary dilution, spiking of separate aliquots for uranium and thorium isotope dilution measurements, and purification of uranium and thorium aliquots for mass spectrometry. This SOP may be applied to uranium samples of unknown purity as in a nuclear forensic investigation, and also to well-characterized samples such as, for example, U{sub 3}O{sub 8} and U-metal certified reference materials. The sample of uranium is transferred to a quartz or PFA vial, concentrated nitric acid is added and the sample is heated on a hotplate at approximately 100 C for several hours until it dissolves. The sample solution is diluted with water to make the solution approximately 4 M HNO{sub 3} and hydrofluoric acid is added to make it 0.05 M HF. A secondary dilution of the primary uranium solution is prepared. Separate aliquots for uranium and thorium isotope dilution measurements are taken and spiked with …
Date: April 18, 2012
Creator: Williams, R. W. & Gaffney, A. M.
Object Type: Report
System: The UNT Digital Library
DECREASE Final Technical Report: Development of a Commercial Ready Enzyme Application System for Ethanol (open access)

DECREASE Final Technical Report: Development of a Commercial Ready Enzyme Application System for Ethanol

Conversion of biomass to sugars plays a central in reducing our dependence on petroleum, as it allows production of a wide range of biobased fuels and chemicals, through fermentation of those sugars. The DECREASE project delivers an effective enzyme cocktail for this conversion, enabling reduced costs for producing advanced biofuels such as cellulosic ethanol. Benefits to the public contributed by growth of the advanced biofuels industry include job creation, economic growth, and energy security. The DECREASE primary project objective was to develop a two-fold improved enzyme cocktail, relative to an advanced cocktail (CZP00005) that had been developed previously (from 2000- 2007). While the final milestone was delivery of all enzyme components as an experimental mixture, a secondary objective was to deploy an improved cocktail within 3 years following the close of the project. In February 2012, Novozymes launched Cellic CTec3, a multi-enzyme cocktail derived in part from components developed under DECREASE. The externally validated performance of CTec3 and an additional component under project benchmarking conditions indicated a 1.8-fold dose reduction in enzyme dose required for 90% conversion (based on all available glucose and xylose sources) of NREL dilute acid pretreated PCS, relative to the starting advanced enzyme cocktail. While the …
Date: April 18, 2012
Creator: Teter, Sarah A
Object Type: Report
System: The UNT Digital Library
Magnetized Target Fusion Collaboration. Final report (open access)

Magnetized Target Fusion Collaboration. Final report

Nuclear fusion has the potential to satisfy the prodigious power that the world will demand in the future, but it has yet to be harnessed as a practical energy source. The entry of fusion as a viable, competitive source of power has been stymied by the challenge of finding an economical way to provide for the confinement and heating of the plasma fuel. It is the contention here that a simpler path to fusion can be achieved by creating fusion conditions in a different regime at small scale (~ a few cm). One such program now under study, referred to as Magnetized Target Fusion (MTF), is directed at obtaining fusion in this high energy density regime by rapidly compressing a compact toroidal plasmoid commonly referred to as a Field Reversed Configuration (FRC). To make fusion practical at this smaller scale, an efficient method for compressing the FRC to fusion gain conditions is required. In one variant of MTF a conducting metal shell is imploded electrically. This radially compresses and heats the FRC plasmoid to fusion conditions. The closed magnetic field in the target plasmoid suppresses the thermal transport to the confining shell, thus lowering the imploding power needed to compress …
Date: April 18, 2012
Creator: Slough, John
Object Type: Report
System: The UNT Digital Library
MicroCT: X-Ray Radiograph Quality Assurance Through the Analysis of Copper Strip Data Using the Matlab CuStrip Analysis GUI (open access)

MicroCT: X-Ray Radiograph Quality Assurance Through the Analysis of Copper Strip Data Using the Matlab CuStrip Analysis GUI

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Date: April 18, 2012
Creator: Seetho, I; Kallman, J S; White, W T & Martz, H E
Object Type: Report
System: The UNT Digital Library
A Note on the Convergence of the Godunov Method for Impact Problems (open access)

A Note on the Convergence of the Godunov Method for Impact Problems

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Date: April 18, 2012
Creator: Banks, J W
Object Type: Article
System: The UNT Digital Library
A Summary of MAGE: A Method for Estimating the Maximum Possible Chemical Energy Content of UCG Product Gas per Unit Area for a Multistrata Coal Zone (open access)

A Summary of MAGE: A Method for Estimating the Maximum Possible Chemical Energy Content of UCG Product Gas per Unit Area for a Multistrata Coal Zone

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Date: April 18, 2012
Creator: Shafirovich, E & Camp, D W
Object Type: Report
System: The UNT Digital Library