States

Impact of CO2 geological sequestration on the nucleation of earthquakes (open access)

Impact of CO2 geological sequestration on the nucleation of earthquakes

None
Date: July 15, 2011
Creator: Cappa, F. & Rutqvist, J.
Object Type: Article
System: The UNT Digital Library
Performance analysis of Darshan 2.2.3 on the Cray XE6 platform. (open access)

Performance analysis of Darshan 2.2.3 on the Cray XE6 platform.

None
Date: November 15, 2012
Creator: Carns, P.; Harms, K.; Latham, R. & Ross, R. (Mathematics and Computer Science)
Object Type: Report
System: The UNT Digital Library
Plasmonics Based Harsh Environment Compatible Chemical Sensors (open access)

Plasmonics Based Harsh Environment Compatible Chemical Sensors

Au-YSZ, Au-TiO{sub 2} and Au-CeO{sub 2} nanocomposite films have been investigated as a potential sensing element for high-temperature plasmonic sensing of H{sub 2}, CO, and NO{sub 2} in an oxygen containing environment. The Au-YSZ and Au-TiO{sub 2} films were deposited using PVD methods, while the CeO{sub 2} thin film was deposited by molecular beam epitaxy (MBE) and Au was implanted into the as-grown film at an elevated temperature followed by high temperature annealing to form well-defined Au nanoclusters. Each of the films were characterized by x-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS). For the gas sensing experiments, separate exposures to varying concentrations of H{sub 2}, CO, and NO{sub 2} were performed at a temperature of 500°C in oxygen backgrounds of 5.0, 10, and ~21% O{sub 2}. Changes in the localized surface plasmon resonance (LSPR) absorption peak were monitored during gas exposures and are believed to be the result of oxidation-reduction processes that fill or create oxygen vacancies in the respective metal oxides. This process affects the LSPR peak position either by charge exchange with the Au nanoparticles or by changes in the dielectric constant surrounding the particles. Hyperspectral multivariate analysis was used to gauge the inherent selectivity of the …
Date: January 15, 2012
Creator: Carpenter, Michael
Object Type: Report
System: The UNT Digital Library
SLUDGE TREATMENT PROJECT ENGINEERED CONTAINER RETRIEVAL AND TRANSFER SYSTEM PRELMINARY DESIGN HAZARD AND OPERABILITY STUDY (open access)

SLUDGE TREATMENT PROJECT ENGINEERED CONTAINER RETRIEVAL AND TRANSFER SYSTEM PRELMINARY DESIGN HAZARD AND OPERABILITY STUDY

This Hazard and Operability (HAZOP) study addresses the Sludge Treatment Project (STP) Engineered Container Retrieval and Transfer System (ECRTS) preliminary design for retrieving sludge from underwater engineered containers located in the 105-K West (KW) Basin, transferring the sludge as a sludge-water slurry (hereafter referred to as 'slurry') to a Sludge Transport and Storage Container (STSC) located in a Modified KW Basin Annex, and preparing the STSC for transport to T Plant using the Sludge Transport System (STS). There are six, underwater engineered containers located in the KW Basin that, at the time of sludge retrieval, will contain an estimated volume of 5.2 m{sup 3} of KW Basin floor and pit sludge, 18.4 m{sup 3} of 105-K East (KE) Basin floor, pit, and canister sludge, and 3.5 m{sup 3} of settler tank sludge. The KE and KW Basin sludge consists of fuel corrosion products (including metallic uranium, and fission and activation products), small fuel fragments, iron and aluminum oxide, sand, dirt, operational debris, and biological debris. The settler tank sludge consists of sludge generated by the washing of KE and KW Basin fuel in the Primary Clean Machine. A detailed description of the origin of sludge and its chemical and physical …
Date: July 15, 2011
Creator: Carro, C. A.
Object Type: Report
System: The UNT Digital Library
UV Excited Photoacoustic Raman (open access)

UV Excited Photoacoustic Raman

None
Date: November 15, 2013
Creator: Carter, J; Chambers, D; Steele, P; Haugen, P & Heller, D
Object Type: Report
System: The UNT Digital Library
Nuclear Explosion Monitoring R&D Roadmap (open access)

Nuclear Explosion Monitoring R&D Roadmap

None
Date: January 15, 2010
Creator: Casey, L; Ziagos, J; Rodgers, A & Bell, W R
Object Type: Article
System: The UNT Digital Library
Innovative Water Management Technology to Reduce Environmental Impacts of Produced Water (open access)

Innovative Water Management Technology to Reduce Environmental Impacts of Produced Water

Clemson University with Chevron as an industry partner developed and applied treatment technology using constructed wetland systems to decrease targeted constituents in simulated and actual produced waters to achieve reuse criteria and discharge limits. Pilot-scale and demonstration constructed wetland treatment system (CWTS) experiments led to design strategies for treating a variety of constituents of concern (COCs) in produced waters including divalent metals, metalloids, oil and grease, and ammonia. Targeted biogeochemical pathways for treatment of COCs in pilot-scale CWTS experiments included divalent metal sulfide precipitation through dissimilatory sulfate reduction, metal precipitation through oxidation, reduction of selenite to insoluble elemental selenium, aerobic biodegradation of oil, nitrification of ammonia to nitrate, denitrification of nitrate to nitrogen gas, separation of oil using an oilwater separator, and sorption of ammonia to zeolite. Treatment performance results indicated that CWTSs can be designed and built to promote specific environmental and geochemical conditions in order for targeted biogeochemical pathways to operate. The demonstration system successfully achieved consistent removal extents even while inflow concentrations of COCs in the produced water differed by orders of magnitude. Design strategies used in the pilot-scale and demonstration CWTSs to promote specific conditions that can be applied to designing full-scale CWTSs include plant and …
Date: May 15, 2013
Creator: Castle, James; Rodgers, John; Alley, Bethany; Beebe, Alex; Coffey, Ruthanne; Jurinko, Kristen et al.
Object Type: Report
System: The UNT Digital Library
Innovative Water Management Technology to Reduce Environment Impacts of Produced Water (open access)

Innovative Water Management Technology to Reduce Environment Impacts of Produced Water

Clemson University with Chevron as an industry partner developed and applied treatment technology using constructed wetland systems to decrease targeted constituents in simulated and actual produced waters to achieve reuse criteria and discharge limits. Pilot-scale and demonstration constructed wetland treatment system (CWTS) experiments led to design strategies for treating a variety of constituents of concern (COCs) in produced waters including divalent metals, metalloids, oil and grease, and ammonia. Targeted biogeochemical pathways for treatment of COCs in pilot-scale CWTS experiments included divalent metal sulfide precipitation through dissimilatory sulfate reduction, metal precipitation through oxidation, reduction of selenite to insoluble elemental selenium, aerobic biodegradation of oil, nitrification of ammonia to nitrate, denitrification of nitrate to nitrogen gas, separation of oil using an oilwater separator, and sorption of ammonia to zeolite. Treatment performance results indicated that CWTSs can be designed and built to promote specific environmental and geochemical conditions in order for targeted biogeochemical pathways to operate. The demonstration system successfully achieved consistent removal extents even while inflow concentrations of COCs in the produced water differed by orders of magnitude. Design strategies used in the pilot-scale and demonstration CWTSs to promote specific conditions that can be applied to designing full-scale CWTSs include plant and …
Date: May 15, 2013
Creator: Castle, James; Rodgers, John; Alley, Bethany; Coffey, Ruthanne; Jurinko, Kristen; Pardue, Michael et al.
Object Type: Report
System: The UNT Digital Library
Innovative Water Management Technology to Reduce Environment Impacts of Produced Water (open access)

Innovative Water Management Technology to Reduce Environment Impacts of Produced Water

Clemson University with Chevron as an industry partner developed and applied treatment technology using constructed wetland systems to decrease targeted constituents in simulated and actual produced waters to achieve reuse criteria and discharge limits. Pilot-scale and demonstration constructed wetland treatment system (CWTS) experiments led to design strategies for treating a variety of constituents of concern (COCs) in produced waters including divalent metals, metalloids, oil and grease, and ammonia. Targeted biogeochemical pathways for treatment of COCs in pilot-scale CWTS experiments included divalent metal sulfide precipitation through dissimilatory sulfate reduction, metal precipitation through oxidation, reduction of selenite to insoluble elemental selenium, aerobic biodegradation of oil, nitrification of ammonia to nitrate, denitrification of nitrate to nitrogen gas, separation of oil using an oilwater separator, and sorption of ammonia to zeolite. Treatment performance results indicated that CWTSs can be designed and built to promote specific environmental and geochemical conditions in order for targeted biogeochemical pathways to operate. The demonstration system successfully achieved consistent removal extents even while inflow concentrations of COCs in the produced water differed by orders of magnitude. Design strategies used in the pilot-scale and demonstration CWTSs to promote specific conditions that can be applied to designing full-scale CWTSs include plant and …
Date: May 15, 2013
Creator: Castle, James; Rodgers, John; Alley, Bethany; Coffey, Ruthanne; Jurinko, Kristen; Pardue, Michael et al.
Object Type: Report
System: The UNT Digital Library
Use of immunomagnetic separation for the detection of Desulfovibrio vulgaris from environmental samples (open access)

Use of immunomagnetic separation for the detection of Desulfovibrio vulgaris from environmental samples

Immunomagnetic separation (IMS) has proved highly efficient for recovering microorganisms from heterogeneous samples. Current investigation targeted the separation of viable cells of the sulfate-reducing bacterium, Desulfovibrio vulgaris. Streptavidin-coupled paramagnetic beads and biotin labeled antibodies raised against surface antigens of this microorganism were used to capture D. vulgaris cells in both bioreactor grown laboratory samples and from extremely low-biomass environmental soil and subsurface drilling samples. Initial studies on detection, recovery efficiency and viability for IMS were performed with laboratory grown D. vulgaris cells using various cell densities. Efficiency of cell isolation and recovery (i.e., release of the microbial cells from the beads following separation) was followed by microscopic imaging and acridine orange direct counts (AODC). Excellent recovery efficiency encouraged the use of IMS to capture Desulfovibrio spp. cells from low-biomass environmental samples. The environmental samples were obtained from a radionuclide-contaminated site in Germany and the chromium (VI)-contaminated Hanford site, an ongoing bioremediation project of the U.S. Department of Energy. Field deployable IMS technology may greatly facilitate environmental sampling and bioremediation process monitoring and enable transcriptomics and proteomics/metabolomics-based studies directly on cells collected from the field.
Date: April 15, 2011
Creator: Chakraborty, R.; Hazen, T. C.; Joyner, D. C.; Kusel, K.; Singer, M. E.; Sitte, J. et al.
Object Type: Article
System: The UNT Digital Library
Analysis of the Noise in Data from the Mt. Meron Array (open access)

Analysis of the Noise in Data from the Mt. Meron Array

None
Date: July 15, 2010
Creator: Chambers, D H & Breitfeller, E
Object Type: Report
System: The UNT Digital Library
Real-Time Vehicle-Mounted Multistatic Ground Penetrating Radar Imaging System for Buried Object Detection (open access)

Real-Time Vehicle-Mounted Multistatic Ground Penetrating Radar Imaging System for Buried Object Detection

None
Date: January 15, 2013
Creator: Chambers, D H; Paglieroni, D W; Mast, J E & Beer, N R
Object Type: Report
System: The UNT Digital Library
Single Electron Dynamic of Microwave Undulator (open access)

Single Electron Dynamic of Microwave Undulator

None
Date: October 15, 2013
Creator: Chang, C.; Neilson, J.; Pellegrini, C.; Shumail, M. & Tantawi, S. G.
Object Type: Article
System: The UNT Digital Library
Kinetics and Mechanisms of Calcite Reactions with Saline Waters (open access)

Kinetics and Mechanisms of Calcite Reactions with Saline Waters

1. Objective The general objective of this research was to determine the kinetics and mechanisms of calcite reactions with saline waters over a wide range of saline water composition, carbon dioxide partial pressure (pCO2), and modest ranges of T and P. This would be done by studying both reaction rates and solubility from changes in solution chemistry. Also, nanoscale observations of calcite surface morphology and composition would be made to provide an understanding of rate controlling mechanisms.
Date: November 15, 2010
Creator: Chapman, Piers & Morse, John W.
Object Type: Report
System: The UNT Digital Library
Theory of Two-Magnon Raman Scattering in Iron Pnictides and Chalcogenides (open access)

Theory of Two-Magnon Raman Scattering in Iron Pnictides and Chalcogenides

Although the parent iron-based pnictides and chalcogenides are itinerant antiferromagnets, the use of local moment picture to understand their magnetic properties is still widespread. We study magnetic Raman scattering from a local moment perspective for various quantum spin models proposed for this new class of superconductors. These models vary greatly in the level of magnetic frustration and show a vastly different two-magnon Raman response. Light scattering by two-magnon excitations thus provides a robust and independent measure of the underlying spin interactions. In accord with other recent experiments, our results indicate that the amount of magnetic frustration in these systems may be small.
Date: August 15, 2011
Creator: Chen, C. C.
Object Type: Article
System: The UNT Digital Library
Final Report for DOE Project Number: DE-FG02-05ER46241 (open access)

Final Report for DOE Project Number: DE-FG02-05ER46241

Hydrogen storage is the most challenging task for the hydrogen economy. We established a multidisciplinary research program for high throughput combinatorial synthesis and characterization of novel nanoporous and metastable complex hydrides, coupled to fundamental material studies including electronic, structural and kinetic transport modeling, and pump-probe experiments. Our research is based the concept of hybrid nanostructures that store hydrogen by a combination of chemi- and physorption: atomic hydrogen is stored in metastable hydrides while molecule hydrogen is stored in the nanometer pores of the hydrides. Metastable nanostructured hydride has been achieved by introducing structural and compositional disorders through high throughput elemental substitution/doping, catalyst addition, and nonequilibrium processing. Fast screening compatible with the combinatorial synthesis was achieved by combining X-ray structural characterization with the development of a laser-based microbalance. Manufacturing of nanoporous metahydrides that are identified as promising by the combinatorial synthesis has been explored along with the materials search.
Date: March 15, 2010
Creator: Chen, Gang; Dresselhaus, Mildred S.; Grigoropoulos, Costas P.; Mao, Samuel S.; Xiang, Xiaodong & Zeng, Taofang
Object Type: Report
System: The UNT Digital Library
Joint inversion of marine seismic AVA and CSEM data using statistical rock-physics models and Markov random fields: Stochastic inversion of AVA and CSEM data (open access)

Joint inversion of marine seismic AVA and CSEM data using statistical rock-physics models and Markov random fields: Stochastic inversion of AVA and CSEM data

Joint inversion of seismic AVA and CSEM data requires rock-physics relationships to link seismic attributes to electrical properties. Ideally, we can connect them through reservoir parameters (e.g., porosity and water saturation) by developing physical-based models, such as Gassmann’s equations and Archie’s law, using nearby borehole logs. This could be difficult in the exploration stage because information available is typically insufficient for choosing suitable rock-physics models and for subsequently obtaining reliable estimates of the associated parameters. The use of improper rock-physics models and the inaccuracy of the estimates of model parameters may cause misleading inversion results. Conversely, it is easy to derive statistical relationships among seismic and electrical attributes and reservoir parameters from distant borehole logs. In this study, we develop a Bayesian model to jointly invert seismic AVA and CSEM data for reservoir parameter estimation using statistical rock-physics models; the spatial dependence of geophysical and reservoir parameters are carried out by lithotypes through Markov random fields. We apply the developed model to a synthetic case, which simulates a CO{sub 2} monitoring application. We derive statistical rock-physics relations from borehole logs at one location and estimate seismic P- and S-wave velocity ratio, acoustic impedance, density, electrical resistivity, lithotypes, porosity, and water …
Date: September 15, 2011
Creator: Chen, J. & Hoversten, G.M.
Object Type: Article
System: The UNT Digital Library
Time-resolved x-ray diffraction across water-ices VI/VII transformations using dynamic-DAC (open access)

Time-resolved x-ray diffraction across water-ices VI/VII transformations using dynamic-DAC

None
Date: October 15, 2013
Creator: Chen, J. Y.; Kim, M.; Yoo, C. & Evans, W. J.
Object Type: Article
System: The UNT Digital Library
Surrogate-based optimization of hydraulic fracturing in pre-existing fracture networks (open access)

Surrogate-based optimization of hydraulic fracturing in pre-existing fracture networks

None
Date: March 15, 2013
Creator: Chen, M; Sun, Y; Fu, P; Carrigan, C R; Lu, Z & Tong, C H
Object Type: Article
System: The UNT Digital Library
Design and Synthesis of Mixed Oxides Nanoparticles for Biofuel Applications (open access)

Design and Synthesis of Mixed Oxides Nanoparticles for Biofuel Applications

The work in this dissertation presents the synthesis of two mixed metal oxides for biofuel applications and NMR characterization of silica materials. In the chapter 2, high catalytic efficiency of calcium silicate is synthesized for transesterfication of soybean oil to biodisels. Chapter 3 describes the synthesis of a new Rh based catalyst on mesoporous manganese oxides. The new catalyst is found to have higher activity and selectivity towards ethanol. Chapter 4 demonstrates the applications of solid-state Si NMR in the silica materials.
Date: May 15, 2010
Creator: Chen, Senniang
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Trace Simulation of Bwr Anticipated Transient Without Scram Leading to Emergency Depressurization (open access)

Trace Simulation of Bwr Anticipated Transient Without Scram Leading to Emergency Depressurization

N/A
Date: June 15, 2014
Creator: Cheng, L. Y.; J., Beak; Cuadra, A.; Aronson, A.; Diamond, D. & Yarsky, P. (with the NRC)
Object Type: Article
System: The UNT Digital Library
The transcriptional diversity of 25 Drosophila cell lines (open access)

The transcriptional diversity of 25 Drosophila cell lines

Drosophila melanogaster cell lines are important resources for cell biologists. Here, we catalog the expression of exons, genes, and unannotated transcriptional signals for 25 lines. Unannotated transcription is substantial (typically 19% of euchromatic signal). Conservatively, we identify 1405 novel transcribed regions; 684 of these appear to be new exons of neighboring, often distant, genes. Sixty-four percent of genes are expressed detectably in at least one line, but only 21% are detected in all lines. Each cell line expresses, on average, 5885 genes, including a common set of 3109. Expression levels vary over several orders of magnitude. Major signaling pathways are well represented: most differentiation pathways are ‘‘off’’ and survival/growth pathways ‘‘on.’’ Roughly 50% of the genes expressed by each line are not part of the common set, and these show considerable individuality. Thirty-one percent are expressed at a higher level in at least one cell line than in any single developmental stage, suggesting that each line is enriched for genes characteristic of small sets of cells. Most remarkable is that imaginal discderived lines can generally be assigned, on the basis of expression, to small territories within developing discs. These mappings reveal unexpected stability of even fine-grained spatial determination. No two …
Date: November 15, 2010
Creator: Cherbas, Lucy; Willingham, Aarron; Zhang, Dayu; Yang, Li; Zou, Yi; Eads, Brian D. et al.
Object Type: Article
System: The UNT Digital Library
Development of Transparent Ceramic Ce-Doped Gadolinium Garnet Gamma Spectrometers (open access)

Development of Transparent Ceramic Ce-Doped Gadolinium Garnet Gamma Spectrometers

None
Date: November 15, 2012
Creator: Cherepy, N J; Seeley, Z M; Payne, S A; Beck, P R; Drury, O B; O'Neal, S P et al.
Object Type: Article
System: The UNT Digital Library
Generalized schemes for high throughput manipulation of the Desulfovibrio vulgaris Hildenborough genome (open access)

Generalized schemes for high throughput manipulation of the Desulfovibrio vulgaris Hildenborough genome

The ability to conduct advanced functional genomic studies of the thousands of sequenced bacteria has been hampered by the lack of available tools for making high- throughput chromosomal manipulations in a systematic manner that can be applied across diverse species. In this work, we highlight the use of synthetic biological tools to assemble custom suicide vectors with reusable and interchangeable DNA “parts” to facilitate chromosomal modification at designated loci. These constructs enable an array of downstream applications including gene replacement and creation of gene fusions with affinity purification or localization tags. We employed this approach to engineer chromosomal modifications in a bacterium that has previously proven difficult to manipulate genetically, Desulfovibrio vulgaris Hildenborough, to generate a library of over 700 strains. Furthermore, we demonstrate how these modifications can be used for examining metabolic pathways, protein-protein interactions, and protein localization. The ubiquity of suicide constructs in gene replacement throughout biology suggests that this approach can be applied to engineer a broad range of species for a diverse array of systems biological applications and is amenable to high-throughput implementation.
Date: July 15, 2011
Creator: Chhabra, S. R.; Butland, G.; Elias, D.; Chandonia, J. M.; Fok, V.; Juba, T. et al.
Object Type: Article
System: The UNT Digital Library