Evaluation of Cross-Hole Seismic Tomography for Imaging Low Resistance Intervals and Associated Carbonate Sediments in Coastal Plain Sequences on the Savannah River Site, South Carolina (open access)

Evaluation of Cross-Hole Seismic Tomography for Imaging Low Resistance Intervals and Associated Carbonate Sediments in Coastal Plain Sequences on the Savannah River Site, South Carolina

The objectives of the pilot study were to investigate the limitations of the technique for imaging the presence, extent, and boundaries of the low-resistance intervals and associated carbonate sediments.
Date: January 5, 1999
Creator: Cumbest, R. J.
System: The UNT Digital Library
Highly Dispersed Pseudo-Homogeneous and Heterogeneous Catalysts Synthesized via Inverse Micelle Solutions for the Liquefaction of Coal (open access)

Highly Dispersed Pseudo-Homogeneous and Heterogeneous Catalysts Synthesized via Inverse Micelle Solutions for the Liquefaction of Coal

The mission of this project was to use inverse micelle solutions to synthesize nanometer sized metal particles and test the particles as catalysts in the liquefaction of coal and other related reactions. The initial focus of the project was the synthesis of iron based materials in pseudo-homogeneous form. The frost three chapters discuss the synthesis, characterization, and catalyst testing in coal liquefaction and model coal liquefaction reactions of iron based pseudo-homogeneous materials. Later, we became interested in highly dispersed catalysts for coprocessing of coal and plastic waste. Bifunctional catalysts . to hydrogenate the coal and depolymerize the plastic waste are ideal. We began studying, based on our previously devised synthesis strategies, the synthesis of heterogeneous catalysts with a bifunctional nature. In chapter 4, we discuss the fundamental principles in heterogeneous catalysis synthesis with inverse micelle solutions. In chapter 5, we extend the synthesis of chapter 4 to practical systems and use the materials in catalyst testing. Finally in chapter 6, we return to iron and coal liquefaction now studied with the heterogeneous catalysts.
Date: January 5, 1999
Creator: Hampden-Smith, M.; Kawola, J. S.; Martino, A.; Sault, A. G. & Yamanaka, S. A.
System: The UNT Digital Library
Task 1.5 Genomic Shift and Drift Trends of Emerging Pathogens (open access)

Task 1.5 Genomic Shift and Drift Trends of Emerging Pathogens

The Lawrence Livermore National Laboratory (LLNL) Bioinformatics group has recently taken on a role in DTRA's Transformation Medical Technologies Initiative (TMTI). The high-level goal of TMTI is to accelerate the development of broad-spectrum countermeasures. To achieve those goals, TMTI has a near term need to conduct analyses of genomic shift and drift trends of emerging pathogens, with a focused eye on select agent pathogens, as well as antibiotic and virulence markers. Most emerging human pathogens are zoonotic viruses with a genome composed of RNA. The high mutation rate of the replication enzymes of RNA viruses contributes to sequence drift and provides one mechanism for these viruses to adapt to diverse hosts (interspecies transmission events) and cause new human and zoonotic diseases. Additionally, new viral pathogens frequently emerge due to genetic shift (recombination and segment reassortment) which allows for dramatic genotypic and phenotypic changes to occur rapidly. Bacterial pathogens also evolve via genetic drift and shift, although sequence drift generally occurs at a much slower rate for bacteria as compared to RNA viruses. However, genetic shift such as lateral gene transfer and inter- and intragenomic recombination enables bacteria to rapidly acquire new mechanisms of survival and antibiotic resistance. New technologies such …
Date: January 5, 2010
Creator: Borucki, M
System: The UNT Digital Library
Predicting tropospheric ozone and hydroxyl radical in a global, three-dimensional, chemistry, transport, and deposition model (open access)

Predicting tropospheric ozone and hydroxyl radical in a global, three-dimensional, chemistry, transport, and deposition model

Two of the most important chemically reactive tropospheric gases are ozone (O{sub 3}) and the hydroxyl radical (OH). Although ozone in the stratosphere is a necessary protector against the sun`s radiation, tropospheric ozone is actually a pollutant which damages materials and vegetation, acts as a respiratory irritant, and is a greenhouse gas. One of the two main sources of ozone in the troposphere is photochemical production. The photochemistry is initiated when hydrocarbons and carbon monoxide (CO) react with nitrogen oxides (NO{sub x} = NO + NO{sub 2}) in the presence of sunlight. Reaction with the hydroxyl radical, OH, is the main sink for many tropospheric gases. The hydroxyl radical is highly reactive and has a lifetime on the order of seconds. Its formation is initiated by the photolysis of tropospheric ozone. Tropospheric chemistry involves a complex, non-linear set of chemical reactions between atmospheric species that vary substantially in time and space. To model these and other species on a global scale requires the use of a global, three-dimensional chemistry, transport, and deposition (CTD) model. In this work, I developed two such three dimensional CTD models. The first model incorporated the chemistry necessary to model tropospheric ozone production from the reactions …
Date: January 5, 1995
Creator: Atherton, C.S.
System: The UNT Digital Library
Using Data to Improve Defense Acquisitions: Background, Analysis, and Questions for Congress (open access)

Using Data to Improve Defense Acquisitions: Background, Analysis, and Questions for Congress

This report examines (1) the extent to which the Department of Defense (DOD) effectively uses data to inform decisionmaking, (2) some of the critical elements needed for DOD to use data more effectively, (3) recent efforts to improve DOD's use of data, and (4) potential questions for Congress. This report focuses primarily (but not exclusively) on defense acquisitions as a case study.
Date: January 5, 2016
Creator: Schwartz, Moshe
System: The UNT Digital Library