Advanced Characterization of Slags and Refractory Bricks Using Electron Backscatter Diffraction (open access)

Advanced Characterization of Slags and Refractory Bricks Using Electron Backscatter Diffraction

Numerous studies have been conducted to determine changes that occur in slag that cause a rapid change in viscosity, but these studies have been limited by the inability to characterize/identify the phases present in the slag. Rapid freezing of slag in entrained gasifiers and slagging combustion systems can cause a shutdown of the system. The reactions occurring in slag that result in rapid freezing of slags are not well understood. It is believed that electron backscatter diffraction (EBSD) can be used to analyze slags and aid in their characterization although its use has not been found in literature. The EBSD technique allows particle-by-particle mineralogy based on diffraction patterns generated by the electron beam when the sample is tilted to a high angle. The diffraction pattern (Kikuchi bands) can only come from crystalline phases, which makes this technique ideally suited to study crystal formation in slags where oftentimes the crystals are very small and a reasonable chemical analysis cannot be made by conventional energy-dispersive spectrometry (EDS) methods in the scanning electron microscope. The ability to have mineralogical data based on the crystalline structure of a phase rather than a chemical analysis by EDS allows much better interpretation of the temperature regimes …
Date: September 30, 2007
Creator: Kay, John & Eylands, Kurt
Object Type: Report
System: The UNT Digital Library
ACRF Instrumentation Status: New, Current, and Future - September – October 2007 (open access)

ACRF Instrumentation Status: New, Current, and Future - September – October 2007

The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) instrumentation status. The report is divided into the following four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) SBIR instrument development.
Date: October 30, 2007
Creator: Voyles, J. W.
Object Type: Report
System: The UNT Digital Library
Patterns and Implications of Gene Gain and Loss in the Evolution of Prochlorococcus (open access)

Patterns and Implications of Gene Gain and Loss in the Evolution of Prochlorococcus

Prochlorococcus is a marine cyanobacterium that numerically dominates the mid-latitude oceans and is the smallest known oxygenic phototroph. Numerous isolatesfrom diverse areas of the world's oceans have been studied and shown to be physiologically and genetically distinct. All isolates described thus far can be assigned to either a tightly clustered high-light (HL)-adapted clade, or a more divergent low-light (LL)-adapted group. The 16S rRNA sequences of the entire Prochlorococcus group differ by at most 3percent, and the four initially published genomes revealed patterns of genetic differentiation that help explain physiological differences among the isolates. Here we describe the genomes of eight newly sequenced isolates and combine them with the first four genomes for a comprehensive analysis of the core (shared by all isolates) and flexible genes of the Prochlorococcus group, and the patterns of loss and gain of the flexible genes over the course of evolution. There are 1,273 genes that represent the core shared by all 12 genomes. They are apparently sufficient, according to metabolic reconstruction, to encode a functional cell. We describe a phylogeny for all 12 isolates by subjecting their complete proteomes to three different phylogenetic analyses. For each non-core gene, we used a maximum parsimony method to …
Date: July 30, 2007
Creator: Lapidus, Alla; Kettler, Gregory C.; Martiny, Adam C.; Huang, Katherine; Zucker, Jeremy; Coleman, Maureen L. et al.
Object Type: Article
System: The UNT Digital Library
Combined Estimation of Hydrogeologic Conceptual Model, Parameter, and Scenario Uncertainty with Application to Uranium Transport at the Hanford Site 300 Area (open access)

Combined Estimation of Hydrogeologic Conceptual Model, Parameter, and Scenario Uncertainty with Application to Uranium Transport at the Hanford Site 300 Area

This report to the Nuclear Regulatory Commission (NRC) describes the development and application of a methodology to systematically and quantitatively assess predictive uncertainty in groundwater flow and transport modeling that considers the combined impact of hydrogeologic uncertainties associated with the conceptual-mathematical basis of a model, model parameters, and the scenario to which the model is applied. The methodology is based on a n extension of a Maximum Likelihood implementation of Bayesian Model Averaging. Model uncertainty is represented by postulating a discrete set of alternative conceptual models for a site with associated prior model probabilities that reflect a belief about the relative plausibility of each model based on its apparent consistency with available knowledge and data. Posterior model probabilities are computed and parameter uncertainty is estimated by calibrating each model to observed system behavior; prior parameter estimates are optionally included. Scenario uncertainty is represented as a discrete set of alternative future conditions affecting boundary conditions, source/sink terms, or other aspects of the models, with associated prior scenario probabilities. A joint assessment of uncertainty results from combining model predictions computed under each scenario using as weight the posterior model and prior scenario probabilities. The uncertainty methodology was applied to modeling of groundwater …
Date: July 30, 2007
Creator: Meyer, Philip D.; Ye, Ming; Rockhold, Mark L.; Neuman, Shlomo P. & Cantrell, Kirk J.
Object Type: Report
System: The UNT Digital Library
The Steubenville Comprehensive Air Monitoring Program (SCAMP) (open access)

The Steubenville Comprehensive Air Monitoring Program (SCAMP)

None
Date: September 30, 2007
Creator: Connell, Daniel P.; Winter, Stephen E.; Suh, Helen; Sarnat, Stefanie; Sullivan, James; Canales, Robert et al.
Object Type: Report
System: The UNT Digital Library
State Support of Domestic Production (open access)

State Support of Domestic Production

This project was developed in response to a cooperative agreement offering by the U.S. Department of Energy (DOE) and the National Energy Technology Laboratory (NETL) under the State Support of Domestic Production DE-FC26-04NT15456. The Interstate Oil and Gas Compact Commission (IOGCC) performed efforts in support of State programs related to the security, reliability and growth if our nation's domestic production of oil and natural gas. The project objectives were to improve the States ability to monitor the security of oil and gas operations; to maximize the production of domestic oil and natural gas thereby minimizing the threat to national security posed by interruptions in energy imports; to assist States in developing and maintaining high standards of environmental protection; to assist in addressing issues that limit the capacity of the industry; to promote the deployment of the appropriate application of technology for regulatory efficiency; and to inform the public about emerging energy issues.
Date: December 30, 2007
Creator: Wright, Amy
Object Type: Report
System: The UNT Digital Library