Corrective Action Decision Document/Closure Report for Corrective Action Unit 383: Area E-Tunnel Sites, Nevada Test Site (open access)

Corrective Action Decision Document/Closure Report for Corrective Action Unit 383: Area E-Tunnel Sites, Nevada Test Site

This Corrective Action Decision Document/Closure Report (CADD/CR) was prepared by the Defense Threat Reduction Agency (DTRA) for Corrective Action Unit (CAU) 383, Area 12 E-Tunnel Sites, which is the joint responsibility of DTRA and the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office (NNSA/NSO). This CADD/CR is consistent with the requirements of the Federal Facility Agreement and Consent Order (FFACO) agreed to by the State of Nevada, the DOE, and the U.S. Department of Defense. Corrective Action Unit 383 is comprised of three Corrective Action Sites (CASs) and two adjacent areas: • CAS 12-06-06, Muckpile • CAS 12-25-02, Oil Spill • CAS 12-28-02, Radioactive Material • Drainage below the Muckpile • Ponds 1, 2, and 3 The purpose of this CADD/CR is to provide justification and documentation to support the recommendation for closure with no further corrective action, by placing use restrictions at the three CASs and two adjacent areas of CAU 383.
Date: March 15, 2010
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
SLAC Cosmic Ray Telescope Facility (open access)

SLAC Cosmic Ray Telescope Facility

SLAC does not have a test beam for the HEP detector development at present. We have therefore created a cosmic ray telescope (CRT) facility, which is presently being used to test the FDIRC prototype. We have used it in the past to debug this prototype with the original SLAC electronics before going to the ESA test beam. Presently, it is used to test a new waveform digitizing electronics developed by the University of Hawaii, and we are also planning to incorporate the new Orsay TDC/ADC electronics. As a next step, we plan to put in a full size DIRC bar box with a new focusing optics, and test it together with a final SuberB electronics. The CRT is located in building 121 at SLAC. We anticipate more users to join in the future. This purpose of this note is to provide an introductory manual for newcomers.
Date: February 15, 2010
Creator: Va'vra, J.
Object Type: Report
System: The UNT Digital Library
Analysis of biostimulated microbial communities from two field experiments reveals temporal and spatial differences in proteome profiles (open access)

Analysis of biostimulated microbial communities from two field experiments reveals temporal and spatial differences in proteome profiles

Stimulated by an acetate-amendment field experiment conducted in 2007, anaerobic microbial populations in the aquifer at the Rifle Integrated Field Research Challenge site in Colorado reduced mobile U(VI) to insoluble U(IV). During this experiment, planktonic biomass was sampled at various time points to quantitatively evaluate proteomes. In 2008, an acetate-amended field experiment was again conducted in a similar manner to the 2007 experiment. As there was no comprehensive metagenome sequence available for use in proteomics analysis, we systematically evaluated 12 different organism genome sequences to generate sets of aggregate genomes, or “pseudo-metagenomes”, for supplying relative quantitative peptide and protein identifications. Proteomics results support previous observations of the dominance of Geobacteraceae during biostimulation using acetate as sole electron donor, and revealed a shift from an early stage of iron reduction to a late stage of iron reduction. Additionally, a shift from iron reduction to sulfate reduction was indicated by changes in the contribution of proteome information contributed by different organism genome sequences within the aggregate set. In addition, the comparison of proteome measurements made between the 2007 field experiment and 2008 field experiment revealed differences in proteome profiles. These differences may be the result of alterations in abundance and population structure …
Date: July 15, 2010
Creator: Callister, S. J.; Wilkins, M. J.; Nicora, C. D.; Williams, K. H.; Banfield, J. F.; VerBerkmoes, N. C. et al.
Object Type: Article
System: The UNT Digital Library
Dynamics of microbial community composition and function during in-situ bioremediation of a uranium-contaminated aquifer (open access)

Dynamics of microbial community composition and function during in-situ bioremediation of a uranium-contaminated aquifer

A pilot-scale system was established to examine the feasibility of in situ U(VI) immobilization at a highly contaminated aquifer (U.S. DOE Integrated Field Research Challenge site, Oak Ridge, TN). Ethanol was injected intermittently as an electron donor to stimulate microbial U(VI) reduction, and U(VI) concentrations fell to below the Environmental Protection Agency drinking water standard (0.03 mg liter{sup -1}). Microbial communities from three monitoring wells were examined during active U(VI) reduction and maintenance phases with GeoChip, a high-density, comprehensive functional gene array. The overall microbial community structure exhibited a considerable shift over the remediation phases examined. GeoChip-based analysis revealed that Fe(III)-reducing bacterial (FeRB), nitrate-reducing bacterial (NRB), and sulfate-reducing bacterial (SRB) functional populations reached their highest levels during the active U(VI) reduction phase (days 137 to 370), in which denitrification and Fe(III) and sulfate reduction occurred sequentially. A gradual decrease in these functional populations occurred when reduction reactions stabilized, suggesting that these functional populations could play an important role in both active U(VI) reduction and maintenance of the stability of reduced U(IV). These results suggest that addition of electron donors stimulated the microbial community to create biogeochemical conditions favorable to U(VI) reduction and prevent the reduced U(IV) from reoxidation and that …
Date: August 15, 2010
Creator: Van Nostrand, J. D.; Wu, L.; Wu, W. M.; Huang, A.; Gentry, T. J.; Deng, Y. et al.
Object Type: Article
System: The UNT Digital Library
Laser-Mechanical Drilling for Geothermal Energy: Low-Contact Drilling Technology to Enable Economical EGS Wells (open access)

Laser-Mechanical Drilling for Geothermal Energy: Low-Contact Drilling Technology to Enable Economical EGS Wells

Broad Funding Opportunity Announcement Project: Foro Energy is developing a unique capability and hardware system to transmit high power lasers over long distances via fiber optic cables. This laser power is integrated with a mechanical drilling bit to enable rapid and sustained penetration of hard rock formations too costly to drill with mechanical drilling bits alone. The laser energy that is directed at the rock basically softens the rock, allowing the mechanical bit to more easily remove it. Foro Energy’s laser-assisted drill bits have the potential to be up to 10 times more economical than conventional hard-rock drilling technologies, making them an effective way to access the U.S. energy resources currently locked under hard rock formations.
Date: January 15, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Corrective Action Decision Document/Closure Report for Corrective Action Unit 476: Area 12 T-Tunnel Muckpile, Nevada Test Site (open access)

Corrective Action Decision Document/Closure Report for Corrective Action Unit 476: Area 12 T-Tunnel Muckpile, Nevada Test Site

This Corrective Action Decision Document (CADD)/Closure Report (CR) was prepared by the Defense Threat Reduction Agency (DTRA) for Corrective Action Unit (CAU) 476, Area 12 T-Tunnel Muckpile. This CADD/CR is consistent with the requirements of the Federal Facility Agreement and Consent Order (FFACO) agreed to by the State of Nevada, the U.S. Department of Energy, and the U.S. Department of Defense. Corrective Action Unit 476 is comprised of one Corrective Action Site (CAS): • 12-06-02, Muckpile The purpose of this CADD/CR is to provide justification and documentation supporting the recommendation for closure in place with use restrictions for CAU 476.
Date: March 15, 2010
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
Corrective Action Decision Document/Closure Report for Corrective Action Unit 559: T Tunnel Compressor/Blower Pad, Nevada Test Site (open access)

Corrective Action Decision Document/Closure Report for Corrective Action Unit 559: T Tunnel Compressor/Blower Pad, Nevada Test Site

This Corrective Action Decision Document (CADD)/Closure Report (CR) was prepared by the Defense Threat Reduction Agency (DTRA) for Corrective Action Unit (CAU) 559, T-Tunnel Compressor/Blower Pad. This CADD/CR is consistent with the requirements of the Federal Facility Agreement and Consent Order (FFACO) agreed to by the State of Nevada, the U.S. Department of Energy, and the U.S. Department of Defense. Corrective Action Unit 559 is comprised of one Corrective Action Site (CAS): • 12-25-13, Oil Stained Soil and Concrete The purpose of this CADD/CR is to provide justification and documentation supporting the recommendation for closure in place with use restrictions for CAU 559.
Date: March 15, 2010
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
Corrective Action Decision Document/Closure Report for Corrective Action Unit 504: 16a-Tunnel Muckpile, Nevada Test Site (open access)

Corrective Action Decision Document/Closure Report for Corrective Action Unit 504: 16a-Tunnel Muckpile, Nevada Test Site

This Corrective Action Decision Document (CADD)/Closure Report (CR) was prepared by the Defense Threat Reduction Agency (DTRA) for Corrective Action Unit (CAU) 504, 16a-Tunnel Muckpile. This CADD/CR is consistent with the requirements of the Federal Facility Agreement and Consent Order (FFACO) agreed to by the State of Nevada; U.S. Department of Energy (DOE), Environmental Management; U.S. Department of Defense; and DOE, Legacy Management. Corrective Action Unit 504 is comprised of four Corrective Action Sites (CASs): • 16-06-01, Muckpile • 16-23-01, Contaminated Burial Pit • 16-23-02, Contaminated Area • 16-99-01, Concrete Construction Waste Corrective Action Site 16-23-01 is not a burial pit; it is part of CAS 16-06-01. Therefore, there is not a separate data analysis and assessment for CAS 16-23-01; it is included as part of the assessment for CAS 16-06-01. In addition to these CASs, the channel between CAS 16-23-02 (Contaminated Area) and Mid Valley Road was investigated with walk-over radiological surveys and soil sampling using hand tools. The purpose of this CADD/CR is to provide justification and documentation supporting the recommendation for closure in place with use restrictions for CAU 504. A CADD was originally submitted for CAU 504 and approved by the Nevada Division of Environmental Protection …
Date: March 15, 2010
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
Corrective Action Decision Document/Closure Report for Corrective Action Unit 477: Area 12 N-Tunnel Muckpile, Nevada Test Site (open access)

Corrective Action Decision Document/Closure Report for Corrective Action Unit 477: Area 12 N-Tunnel Muckpile, Nevada Test Site

This Corrective Action Decision Document (CADD)/Closure Report (CR) was prepared by the Defense Threat Reduction Agency (DTRA) for Corrective Action Unit (CAU) 477, N-Tunnel Muckpile. This CADD/CR is consistent with the requirements of the Federal Facility Agreement and Consent Order (FFACO) agreed to by the State of Nevada, the U.S. Department of Energy, and the U.S. Department of Defense. Corrective Action Unit 477 is comprised of one Corrective Action Site (CAS): • 12-06-03, Muckpile The purpose of this CADD/CR is to provide justification and documentation supporting the recommendation for closure with no further action, by placing use restrictions on CAU 477.
Date: March 15, 2010
Creator: National Security Technologies, LLC
Object Type: Report
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
Liquid Fuel From Bacteria: Engineering Ralstonia eutropha for Production of Isobutanol (IBT) Motor Fuel from CO2, Hydrogen, and Oxygen (open access)

Liquid Fuel From Bacteria: Engineering Ralstonia eutropha for Production of Isobutanol (IBT) Motor Fuel from CO2, Hydrogen, and Oxygen

Electrofuels Project: MIT is using solar-derived hydrogen and common soil bacteria called Ralstonia eutropha to turn carbon dioxide (CO2) directly into biofuel. This bacteria already has the natural ability to use hydrogen and CO2 for growth. MIT is engineering the bacteria to use hydrogen to convert CO2 directly into liquid transportation fuels. Hydrogen is a flammable gas, so the MIT team is building an innovative reactor system that will safely house the bacteria and gas mixture during the fuel-creation process. The system will pump in precise mixtures of hydrogen, oxygen, and CO2, and the online fuel-recovery system will continuously capture and remove the biofuel product.
Date: July 15, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Natural Oil Production from Microorganisms: Bioprocess and Microbe Engineering for Total Carbon Utilization in Biofuel Production (open access)

Natural Oil Production from Microorganisms: Bioprocess and Microbe Engineering for Total Carbon Utilization in Biofuel Production

Electrofuels Project: MIT is using carbon dioxide (CO2) and hydrogen generated from electricity to produce natural oils that can be upgraded to hydrocarbon fuels. MIT has designed a 2-stage biofuel production system. In the first stage, hydrogen and CO2 are fed to a microorganism capable of converting these feedstocks to a 2-carbon compound called acetate. In the second stage, acetate is delivered to a different microorganism that can use the acetate to grow and produce oil. The oil can be removed from the reactor tank and chemically converted to various hydrocarbons. The electricity for the process could be supplied from novel means currently in development, or more proven methods such as the combustion of municipal waste, which would also generate the required CO2 and enhance the overall efficiency of MIT’s biofuel-production system.
Date: July 15, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Phased array compaction cell for measurement of the transversely isotropic elastic properties of compacting sediments (open access)

Phased array compaction cell for measurement of the transversely isotropic elastic properties of compacting sediments

Sediments undergoing compaction typically exhibit transversely isotropic (TI) elastic properties. We present a new experimental apparatus, the phased array compaction cell, for measuring the TI elastic properties of clay-rich sediments during compaction. This apparatus uses matched sets of P- and S-wave ultrasonic transducers located along the sides of the sample and an ultrasonic P-wave phased array source, together with a miniature P-wave receiver on the top and bottom ends of the sample. The phased array measurements are used to form plane P-waves that provide estimates of the phase velocities over a range of angles. From these measurements, the five TI elastic constants can be recovered as the sediment is compacted, without the need for sample unloading, recoring, or reorienting. This paper provides descriptions of the apparatus, the data processing, and an application demonstrating recovery of the evolving TI properties of a compacting marine sediment sample.
Date: December 15, 2010
Creator: Nihei, K.T.; Nakagawa, S.; Reverdy, F.; Meyer, L.R.; Duranti, L. & Ball, G.
Object Type: Article
System: The UNT Digital Library
Corrective Action Decision Document/Closure Report for Corrective Action Unit 478: Area 12 T-Tunnel Ponds, Nevada Test Site (open access)

Corrective Action Decision Document/Closure Report for Corrective Action Unit 478: Area 12 T-Tunnel Ponds, Nevada Test Site

This Corrective Action Decision Document (CADD)/Closure Report (CR) was prepared by the Defense Threat Reduction Agency (DTRA) for Corrective Action Unit (CAU) 478, Area 12 T-Tunnel Ponds. This CADD/CR is consistent with the requirements of the Federal Facility Agreement and Consent Order (FFACO) agreed to by the State of Nevada, the U.S. Department of Energy (DOE), and the U.S. Department of Defense. Corrective Action Unit 478 is comprised of one corrective action site (CAS): • 12-23-01, Ponds (5) RAD Area The purpose of this CADD/CR is to provide justification and documentation supporting the recommendation for closure in place with use restrictions for CAU 478.
Date: March 15, 2010
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
Tethered Lubricants (open access)

Tethered Lubricants

We have performed extensive experimental and theoretical studies of interfacial friction, relaxation dynamics, and thermodynamics of polymer chains tethered to points, planes, and particles. A key result from our tribology studies using lateral force microscopy (LFM) measurements of polydisperse brushes of linear and branched chains densely grafted to planar substrates is that there are exceedingly low friction coefficients for these systems. Specific project achievements include: (1) Synthesis of three-tiered lubricant films containing controlled amounts of free and pendent PDMS chains, and investigated the effect of their molecular weight and volume fraction on interfacial friction. (2.) Detailed studies of a family of hairy particles termed nanoscale organic hybrid materials (NOHMs) and demonstration of their use as lubricants.
Date: September 15, 2010
Creator: Archer, Lynden
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
Solid Oxide Fuel Cell Development for Auxiliary Power in Heavy Duty Vehicle Applications (open access)

Solid Oxide Fuel Cell Development for Auxiliary Power in Heavy Duty Vehicle Applications

Changing economic and environmental needs of the trucking industry is driving the use of auxiliary power unit (APU) technology for over the road haul trucks. The trucking industry in the United States remains the key to the economy of the nation and one of the major changes affecting the trucking industry is the reduction of engine idling. Delphi Automotive Systems, LLC (Delphi) teamed with heavy-duty truck Original Equipment Manufacturers (OEMs) PACCAR Incorporated (PACCAR), and Volvo Trucks North America (VTNA) to define system level requirements and develop an SOFC based APU. The project defines system level requirements, and subsequently designs and implements an optimized system architecture using an SOFC APU to demonstrate and validate that the APU will meet system level goals. The primary focus is on APUs in the range of 3-5 kW for truck idling reduction. Fuels utilized were derived from low-sulfur diesel fuel. Key areas of study and development included sulfur remediation with reformer operation; stack sensitivity testing; testing of catalyst carbon plugging and combustion start plugging; system pre-combustion; and overall system and electrical integration. This development, once fully implemented and commercialized, has the potential to significantly reduce the fuel idling Class 7/8 trucks consume. In addition, the …
Date: June 15, 2010
Creator: Hennessy, Daniel T.
Object Type: Report
System: The UNT Digital Library
How People Actually Use Thermostats (open access)

How People Actually Use Thermostats

Residential thermostats have been a key element in controlling heating and cooling systems for over sixty years. However, today's modern programmable thermostats (PTs) are complicated and difficult for users to understand, leading to errors in operation and wasted energy. Four separate tests of usability were conducted in preparation for a larger study. These tests included personal interviews, an on-line survey, photographing actual thermostat settings, and measurements of ability to accomplish four tasks related to effective use of a PT. The interviews revealed that many occupants used the PT as an on-off switch and most demonstrated little knowledge of how to operate it. The on-line survey found that 89% of the respondents rarely or never used the PT to set a weekday or weekend program. The photographic survey (in low income homes) found that only 30% of the PTs were actually programmed. In the usability test, we found that we could quantify the difference in usability of two PTs as measured in time to accomplish tasks. Users accomplished the tasks in consistently shorter times with the touchscreen unit than with buttons. None of these studies are representative of the entire population of users but, together, they illustrate the importance of improving …
Date: August 15, 2010
Creator: Meier, Alan; Aragon, Cecilia; Hurwitz, Becky; Mujumdar, Dhawal; Peffer, Therese; Perry, Daniel et al.
Object Type: Article
System: The UNT Digital Library
A truncated Levenberg-Marquardt algorithm for the calibration of highly parameterized nonlinear models (open access)

A truncated Levenberg-Marquardt algorithm for the calibration of highly parameterized nonlinear models

We propose a modification to the Levenberg-Marquardt minimization algorithm for a more robust and more efficient calibration of highly parameterized, strongly nonlinear models of multiphase flow through porous media. The new method combines the advantages of truncated singular value decomposition with those of the classical Levenberg-Marquardt algorithm, thus enabling a more robust solution of underdetermined inverse problems with complex relations between the parameters to be estimated and the observable state variables used for calibration. The truncation limit separating the solution space from the calibration null space is re-evaluated during the iterative calibration process. In between these re-evaluations, fewer forward simulations are required, compared to the standard approach, to calculate the approximate sensitivity matrix. Truncated singular values are used to calculate the Levenberg-Marquardt parameter updates, ensuring that safe small steps along the steepest-descent direction are taken for highly correlated parameters of low sensitivity, whereas efficient quasi-Gauss-Newton steps are taken for independent parameters with high impact. The performance of the proposed scheme is demonstrated for a synthetic data set representing infiltration into a partially saturated, heterogeneous soil, where hydrogeological, petrophysical, and geostatistical parameters are estimated based on the joint inversion of hydrological and geophysical data.
Date: October 15, 2010
Creator: Finsterle, S. & Kowalsky, M.B.
Object Type: Article
System: The UNT Digital Library
Adult Human Pancreatic Islet Beta-Cells Display Limited Turnover and Long Lifespan as Determined by In-Vivo Thymidine Analog Incorporation and Radiocarbon Dating (open access)

Adult Human Pancreatic Islet Beta-Cells Display Limited Turnover and Long Lifespan as Determined by In-Vivo Thymidine Analog Incorporation and Radiocarbon Dating

Diabetes mellitus results from an absolute or relative deficiency of insulin producing pancreatic beta-cells. The adult human beta-cell's turnover rate remains unknown. We employed novel techniques to examine adult human islet beta-cell turnover and longevity in vivo. Subjects enrolled in NIH clinical trials received thymidine analogues [iododeoxyuridine (IdU) or bromodeoxyuridine (BrdU)] 8-days to 4-years prior to death. Archival autopsy samples from ten patients (aged 17-74 years) were employed to assess beta-cell turnover by scoring nuclear analog labeling within insulin staining cells. Human adult beta-cell longevity was determined by estimating the cells genomic DNA integration of atmospheric carbon-14 ({sup 14}C). DNA was purified from pancreatic islets isolated from cadaveric donors; whole islet prep DNA was obtained from a 15 year old donor, and purified beta-cell DNA was obtained from two donors (age 48 and 80 years). {sup 14}C levels were then determined using accelerator mass spectrometry (AMS). Cellular 'birth date' was determined by comparing the subject's DNA {sup 14}C content relative to a well-established {sup 14}C atmospheric prevalence curve. In the two subjects less than age 20 years, 1-2% of the beta-cell nuclei co-stained for BrdU/IdU. No beta-cell nuclei co-stained in the eight patients more than 30 years old. Consistent with …
Date: March 15, 2010
Creator: Perl, S.; Kushner, J. A.; Buchholz, B. A.; Meeker, A. K.; Stein, G. M.; Hsieh, M. et al.
Object Type: Article
System: The UNT Digital Library
Evaluation of Glass Density to Support the Estimation of Fissile Mass Loadings from Iron Concentrations in SB6 Glasses (open access)

Evaluation of Glass Density to Support the Estimation of Fissile Mass Loadings from Iron Concentrations in SB6 Glasses

The Department of Energy - Savannah River (DOE-SR) previously provided direction to Savannah River Remediation (SRR) to maintain fissile concentration in glass below 897 g/m{sup 3}. In support of the guidance, the Savannah River National Laboratory (SRNL) provided a technical basis and a supporting Microsoft{reg_sign} Excel{reg_sign} spreadsheet for the evaluation of fissile loading in Sludge Batch 5 glass based on the Fe concentration in glass as determined by the measurements from the Slurry Mix Evaporator (SME) acceptability analysis. SRR has since requested that SRNL provide the necessary information to allow SRR to update the Excel spreadsheet so that it may be used to maintain fissile concentration in glass below 897 g/m{sup 3} during the processing of Sludge Batch 6 (SB6). One of the primary inputs into the fissile loading spreadsheet includes a bounding density for SB6-based glasses. Based on the measured density data of select SB6 variability study glasses, SRNL recommends that SRR utilize the 99/99 Upper Tolerance Limit (UTL) density value at 38% WL (2.823 g/cm{sup 3}) as a bounding density for SB6 glasses to assess the fissile concentration in this glass system. That is, the 2.823 g/cm{sup 3} is recommended as a key (and fixed) input into the …
Date: December 15, 2010
Creator: Edwards, T. & Peeler, D.
Object Type: Report
System: The UNT Digital Library
The Role of Quench-back in the Passive Quench Protection of Uncoupled Solenoids in Series with and without Coil Sub-division (open access)

The Role of Quench-back in the Passive Quench Protection of Uncoupled Solenoids in Series with and without Coil Sub-division

This paper is the final paper in a series of papers that discusses passive quench protection for high inductance solenoid magnets. This report describes how passive quench protection system may be applied to superconducting magnets that are connected in series but not inductively coupled. Previous papers have discussed the role of magnet sub-division and quench back from a conductive mandrel in reducing the hot-spot temperature and the peak coil voltages to ground. When magnets are connected in series, quench-back from a conductive mandrel can cause other magnets in a string to quench even without inductive coupling between magnets. The magnet mandrels must be well coupled to the magnet circuit that is being quenched. When magnet circuit sub-division is employed to reduce the voltages-to-ground within magnets, the resistance across the subdivision becomes the most important factor in the successful quenching of the magnet string.
Date: October 15, 2010
Creator: Guo, Xing Long; Green, Michael A; Wang, Li; Wu, Hong & Pan, Heng
Object Type: Article
System: The UNT Digital Library
Modeling of fate and transport of co-injection of H2S with CO2 in deep saline formations (open access)

Modeling of fate and transport of co-injection of H2S with CO2 in deep saline formations

The geological storage of CO{sub 2} in deep saline formations is increasing seen as a viable strategy to reduce the release of greenhouse gases into the atmosphere. However, costs of capture and compression of CO{sub 2} from industrial waste streams containing small quantities of sulfur and nitrogen compounds such as SO{sub 2}, H{sub 2}S and N{sub 2} are very expensive. Therefore, studies on the co-injection of CO{sub 2} containing other acid gases from industrial emissions are very important. In this paper, numerical simulations were performed to study the co-injection of H{sub 2}S with CO{sub 2} in sandstone and carbonate formations. Results indicate that the preferential dissolution of H{sub 2}S gas (compared with CO{sub 2} gas) into formation water results in the delayed breakthrough of H{sub 2}S gas. Co-injection of H{sub 2}S results in the precipitation of pyrite through interactions between the dissolved H{sub 2}S and Fe{sup 2+} from the dissolution of Fe-bearing minerals. Additional injection of H{sub 2}S reduces the capabilities for solubility and mineral trappings of CO{sub 2} compared to the CO{sub 2} only case. In comparison to the sandstone (siliciclastic) formation, the carbonate formation is less favorable to the mineral sequestration of CO{sub 2}. Different from CO{sub 2} …
Date: December 15, 2010
Creator: Zhang, W.; Xu, T. & Li, Y.
Object Type: Article
System: The UNT Digital Library
Transport and deposition of functionalized CdTe nanoparticles in saturated porous media (open access)

Transport and deposition of functionalized CdTe nanoparticles in saturated porous media

Comprehensive understanding of the transport and deposition of engineered nanoparticles (NPs) in subsurface is required to assess their potential negative impact on the environment. We studied the deposition behavior of functionalized quantum dot (QD) NPs (CdTe) in different types of sands (Accusand, ultrapure quartz, and iron-coated sand) at various solution ionic strengths (IS). The observed transport behavior in ultrapure quartz and iron-coated sand was consistent with conventional colloid deposition theories. However, our results from the Accusand column showed that deposition was minimal at the lowest IS (1 mM) and increased significantly as the IS increased. The effluent breakthrough occurred with a delay, followed by a rapid rise to the maximum normalized concentration of unity. Negligible deposition in the column packed with ultrapure quartz sand (100 mM) and Accusand (1 mM) rules out the effect of straining and suggests the importance of surface charge heterogeneity in QD deposition in Accusand at higher IS. Data analyses further show that only a small fraction of sand surface area contributed in QD deposition even at the highest IS (100 mM) tested. The observed delay in breakthrough curves of QDs was attributed to the fast diffusive mass transfer rate of QDs from bulk solution to …
Date: October 15, 2010
Creator: Torkzaban, S.; Wan, J.; Kim, Y.; Mulvihill, M. & Tokunaga, T. K.
Object Type: Article
System: The UNT Digital Library