Comparison of Edge Plasma Perturbation During ELM Control Using One vs Two Toroidal Rows of RMP Coils in ITER Similar Shaped Plasmas on DIII-D (open access)

Comparison of Edge Plasma Perturbation During ELM Control Using One vs Two Toroidal Rows of RMP Coils in ITER Similar Shaped Plasmas on DIII-D

Large Type-I edge localized modes (ELMs) were suppressed by n = 3 resonant magnetic perturbations (RMPs) from a set of internal coils (I-coil) in plasmas with an ITER similar shape at the ITER pedestal collisionality, {nu}*{sub e} {approx} 0.1 and low edge safety factor (q{sub 95} {approx} 3.6), with either a single toroidal row of the internal RMP coils or two poloidally separated rows of coils. ELM suppression with a single row of internal coils was achieved at approximately the same q{sub 95} surface-averaged perturbation field as with two rows of coils, but required higher current per coil. Maintaining complete suppression of ELMs using n = 3 RMPs from a single toroidal row of internal coils was less robust to variations in input neutral beam injection torque than previous ELM suppression cases using both rows of internal coils. With either configuration of RMP coils, maximum ELM size is correlated with the width of the edge region having good overlap of the magnetic islands from vacuum field calculations.
Date: May 21, 2008
Creator: Fenstermacher, M. E.; Evans, T. E.; Osborne, T. H.; Schaffer, M. J.; deGrassie, J. S.; Gohil, P. et al.
Object Type: Article
System: The UNT Digital Library
Raman Spectroscopy of Carbon Dust Samples from NSTX (open access)

Raman Spectroscopy of Carbon Dust Samples from NSTX

The Raman spectrum of dust particles exposed to the NSTX plasma is different from the spectrum of unexposed particles scraped from an unused graphite tile. For the unexposed particles, the high energy G-mode peak (Raman shift ~1580 cm-1) is much stronger than the defect-induced D-mode peak (Raman shift ~ 1350 cm-1), a pattern that is consistent with Raman spectrum for commercial graphite materials. For dust particles exposed to the plasma, the ratio of G-mode to D-mode peaks is lower and becomes even less than 1. The Raman measurements indicate that the production of carbon dust particles in NSTX involves modifications of the physical and chemical structure of the original graphite material. These modifications are shown to be similar to those measured for carbon deposits from atmospheric pressure helium arc discharge with an ablating anode electrode made from a graphite tile material. We also demonstrate experimentally that heating to 2000-2700 K alone can not explain the observed structural modifications indicating that they must be due to higher temperatures needed for graphite vaporization, which is followed either by condensation or some plasma-induced processes leading to the formation of more disordered forms of carbon material than the original graphite.
Date: February 21, 2008
Creator: Y. Raitses, C.H. Skinner, F. Jiang and T.S. Duffy
Object Type: Article
System: The UNT Digital Library
Environmental Management Waste Management Facility (EMWMF) Site-Specific Health and Safety Plan, Oak Ridge, Tennessee (open access)

Environmental Management Waste Management Facility (EMWMF) Site-Specific Health and Safety Plan, Oak Ridge, Tennessee

The Bechtel Jacobs Company LLC (BJC) policy is to provide a safe and healthy workplace for all employees and subcontractors. The implementation of this policy requires that operations of the Environmental Management Waste Management Facility (EMWMF), located one-half mile west of the U.S. Department of Energy (DOE) Y-12 National Security Complex, be guided by an overall plan and consistent proactive approach to environment, safety and health (ES&H) issues. The BJC governing document for worker safety and health, BJC/OR-1745, 'Worker Safety and Health Program', describes the key elements of the BJC Safety and Industrial Hygiene (IH) programs, which includes the requirement for development and implementation of a site-specific Health and Safety Plan (HASP) where required by regulation (refer also to BJC-EH-1012, 'Development and Approval of Safety and Health Plans'). BJC/OR-1745, 'Worker Safety and Health Program', implements the requirements for worker protection contained in Title 10 Code of Federal Regulations (CFR) Part 851. The EMWMF site-specific HASP requirements identifies safe operating procedures, work controls, personal protective equipment, roles and responsibilities, potential site hazards and control measures, site access requirements, frequency and types of monitoring, site work areas, decontamination procedures, and outlines emergency response actions. This HASP will be available on site for …
Date: April 21, 2008
Creator: Flynn, N.C. Bechtel Jacobs
Object Type: Report
System: The UNT Digital Library
Simultaneously Bound Guests and Chiral Recognition: a Chiral Self-Assembled Supramolecular Host Encapsulates Hydrophobic Guests (open access)

Simultaneously Bound Guests and Chiral Recognition: a Chiral Self-Assembled Supramolecular Host Encapsulates Hydrophobic Guests

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Date: May 21, 2008
Creator: Hastings, Courtney; Pluth, Michael; Biros, Shannon; Bergman, Robert & Raymond, Kenneth
Object Type: Article
System: The UNT Digital Library
Integrating Human Indoor Air Pollutant Exposure within Life Cycle Impact Assessment (open access)

Integrating Human Indoor Air Pollutant Exposure within Life Cycle Impact Assessment

Neglecting health effects from indoor pollutant emissions and exposure, as currently done in Life Cycle Assessment (LCA), may result in product or process optimizations at the expense of workers? or consumers? health. To close this gap, methods for considering indoor exposure to chemicals are needed to complement the methods for outdoor human exposure assessment already in use. This paper summarizes the work of an international expert group on the integration of human indoor and outdoor exposure in LCA, within the UNEP/SETAC Life Cycle Initiative. A new methodological framework is proposed for a general procedure to include human-health effects from indoor exposure in LCA. Exposure models from occupational hygiene and household indoor air quality studies and practices are critically reviewed and recommendations are provided on the appropriateness of various model alternatives in the context of LCA. A single-compartment box model is recommended for use as a default in LCA, enabling one to screen occupational and household exposures consistent with the existing models to assess outdoor emission in a multimedia environment. An initial set of model parameter values was collected. The comparison between indoor and outdoor human exposure per unit of emission shows that for many pollutants, intake per unit of indoor …
Date: December 21, 2008
Creator: Hellweg, Stefanie; Demou, Evangelia; Bruzzi, Raffaella; Meijer, Arjen; Rosenbaum, Ralph K.; Huijbregts, Mark A.J. et al.
Object Type: Article
System: The UNT Digital Library
Correlation Analysis of TEM Images of Nanocrystal Molecules (open access)

Correlation Analysis of TEM Images of Nanocrystal Molecules

Quantitative characterizataion of images of naocrystals and nanostructures is a challenging but important task. The development and optimization of methods for the construction of complex nanostructures rely on imaging techniques. Computer programs were developed to quantify TEM images of nanocrystal/DNA nanostructures, and results are presented for heterodimers annd trimers of gold nanocrystals. The programs presented here have also been used to analyze more complex trimers and tetramers linked by branched DNA, as well as for structures made from attaching gold nanocrystals to CdSe/ZnS core-shell quantum dots. This work has the additional goal of enabling others to quickly and easily adapt the methods for their own use.
Date: May 21, 2008
Creator: Micheel, Christine; Zanchet, Daniele & Alivisatos, A. Paul
Object Type: Article
System: The UNT Digital Library
Chromatin condensation in terminally differentiating mouse erythroblasts does not involve special architectural proteins but depends on histone deacetylation (open access)

Chromatin condensation in terminally differentiating mouse erythroblasts does not involve special architectural proteins but depends on histone deacetylation

Terminal erythroid differentiation in vertebrates is characterized by progressive heterochromatin formation, chromatin condensation and, in mammals, culminates in nuclear extrusion. To date, although mechanisms regulating avian erythroid chromatin condensation have been identified, little is known regarding this process during mammalian erythropoiesis. To elucidate the molecular basis for mammalian erythroblast chromatin condensation, we used Friend virus-infected murine spleen erythroblasts that undergo terminal differentiation in vitro. Chromatin isolated from early and late stage erythroblasts had similar levels of linker and core histones, only a slight difference in nucleosome repeats, and no significant accumulation of known developmentally-regulated architectural chromatin proteins. However, histone H3(K9) dimethylation markedly increased while histone H4(K12) acetylation dramatically decreased and became segregated from the histone methylation as chromatin condensed. One histone deacetylase, HDAC5, was significantly upregulated during the terminal stages of Friend virus-infected erythroblast differentiation. Treatment with histone deacetylase inhibitor, trichostatin A, blocked both chromatin condensation and nuclear extrusion. Based on our data, we propose a model for a unique mechanism in which extensive histone deacetylation at pericentromeric heterochromatin mediates heterochromatin condensation in vertebrate erythroblasts that would otherwise be mediated by developmentally-regulated architectural proteins in nucleated blood cells.
Date: August 21, 2008
Creator: Popova, Evgenya Y.; Krauss, Sharon Wald; Short, Sarah A.; Lee, Gloria; Villalobos, Jonathan; Etzell, Joan et al.
Object Type: Article
System: The UNT Digital Library
System size, energy and centrality dependence of strange hadron elliptic flow at STAR (open access)

System size, energy and centrality dependence of strange hadron elliptic flow at STAR

The elliptic flow (v{sub 2}) pattern in terms of hadron mass and transverse momentum p{sub T} is qualitatively described for p{sub T} < 2 GeV/c by ideal hydrodynamics in Au + Au collisions at RHIC. In addition, for p{sub T} = 2-6 GeV/c the measured v{sub 2} follow a universal scaling by the number of quarks explained by quark coalescence/recombination models. These observations suggest that a partonic collectivity develops in the matter in early stage of heavy ion collisions. Centrality as well as system size and energy dependence of the v{sub 2} is important to shed light on the underlying collision dynamics in heavy ion collisions. We present the measurements of centrality dependence of v{sub 2} at {radical}s{sub NN} = 200 and 62.4 GeV in Au + Au and Cu + Cu collisions for K{sub S}{sup 0}, {phi}, {Lambda}, {Xi} and {Omega} at STAR experiment. We focus on the recent Cu + Cu results and discuss the centrality dependence of v{sub 2} as well as the number of quark scaling as a function of transverse kinetic energy at different system size and energies. We also discuss the eccentricity scaled v{sub 2} for identified hadrons and implications that ideal hydrodynamical limit …
Date: December 21, 2008
Creator: Masui, Hiroshi
Object Type: Article
System: The UNT Digital Library
Interpretation of the Finite Pressure Gradient Effects in the Reversed Shear Alfvén Eigenmode Theory (open access)

Interpretation of the Finite Pressure Gradient Effects in the Reversed Shear Alfvén Eigenmode Theory

Ideal MHD equations employed in the NOVA code are analyzed analytically and numerically in order to investigate the role of the pressure gradient on global reversed shear Alfvén eigenmodes (RSAEs) or Alfvén cascades. We confirm both numerically and analytically conclusions obtained earlier using the ideal MHD code NOVA and analytically that the plasma pressure gradient plays a key role in the existence condition and in the dispersion relation for the mode. The effect of the plasma pressure gradient is to shift the mode frequency up at the low part of the RSAE frequency chirp and downshift the mode frequency when the frequency approaches the TAE gap This finding is opposite to predictions in a recent publication , where the pressure gradient is found to be always stabilizing by means of downshifting the RSAE frequency and enhancing its in- teraction with the continuum. We resolve this discrepancy by showing that neglecting the pressure gradient effect on the plasma equilibrium (modification of the Shafranov shift and the averaged curvature) leads to conclusions at variance to the numerical and analytical results presented here. A new variational approximation of the RSAE is introduced which compares remarkably well with NOVA solutions. With this new approximation …
Date: February 21, 2008
Creator: N.N. Gorelenkov, G.J. Kramer, R. Nazikian
Object Type: Report
System: The UNT Digital Library
System Description for the K-25/K-27 D&D Project Polyurethane Foam Delivery System, East Tennessee Technology Park, Oak Ridge, Tennessee (open access)

System Description for the K-25/K-27 D&D Project Polyurethane Foam Delivery System, East Tennessee Technology Park, Oak Ridge, Tennessee

The Foam Delivery System used in the decontamination and decommissioning (D&D) project for the K-25/K-27 Buildings at the East Tennessee Technology Park (ETTP) is comprised of a trailer-mounted Gusmer{reg_sign} H20/35 Pro-TEC Proportioning Unit and the associated equipment to convey electrical power, air, and foam component material to the unit. This high-pressure, plural-component polyurethane foam pouring system will be used to fill process gas and non-process equipment/piping (PGE/P) within the K-25/K-27 Buildings with polyurethane foam to immobilize contaminants prior to removal. The system creates foam by mixing isocyanate and polyol resin (Resin) component materials. Currently, the project plans to utilize up to six foaming units simultaneously during peak foaming activities. Also included in this system description are the foam component material storage containers that will be used for storage of the component material drums in a staging area outside of the K-25/K-27 Buildings. The Foam Delivery System and foam component material storage enclosures (i.e., Foaming Component Protective Enclosures) used to store polymeric methylene diphenyl diisocyanate (PMDI) component material are identified as Safety Significant (SS) Structures, Systems and Components (SSC) in the Documented Safety Analysis (DSA) for the project, Documented Safety Analysis for the K-25 and K-27 Facilities at the East Tennessee …
Date: February 21, 2008
Creator: Boris, G.
Object Type: Report
System: The UNT Digital Library
Beam Energy and System Size Dependence of Dynamical Net Charge Fluctuations (open access)

Beam Energy and System Size Dependence of Dynamical Net Charge Fluctuations

We present measurements of net charge fluctuations in Au + Au collisions at {radical}s{sub NN} = 19.6, 62.4, 130, and 200 GeV, Cu + Cu collisions at {radical}s{sub NN} = 62.4, 200 GeV, and p + p collisions at {radical}s = 200 GeV using the dynamical net charge fluctuations measure {nu}{sub {+-},dyn}. We observe that the dynamical fluctuations are non-zero at all energies and exhibit a modest dependence on beam energy. A weak system size dependence is also observed. We examine the collision centrality dependence of the net charge fluctuations and find that dynamical net charge fluctuations violate 1/N{sub ch} scaling, but display approximate 1/N{sub part} scaling. We also study the azimuthal and rapidity dependence of the net charge correlation strength and observe strong dependence on the azimuthal angular range and pseudorapidity widths integrated to measure the correlation.
Date: July 21, 2008
Creator: STAR Collaboration
Object Type: Article
System: The UNT Digital Library
The Length of Time's Arrow (open access)

The Length of Time's Arrow

An unresolved problem in physics is how the thermodynamic arrow of time arises from an underlying time reversible dynamics. We contribute to this issue by developing a measure of time-symmetry breaking, and by using the work fluctuation relations, we determine the time asymmetry of recent single molecule RNA unfolding experiments. We define time asymmetry as the Jensen-Shannon divergencebetween trajectory probability distributions of an experiment and its time-reversed conjugate. Among other interesting properties, the length of time's arrow bounds the average dissipation and determines the difficulty of accurately estimating free energy differences in nonequilibrium experiments.
Date: August 21, 2008
Creator: Feng, Edward H. & Crooks, Gavin E.
Object Type: Article
System: The UNT Digital Library
Evidence for the incorporation of lead into barite from waste rock pile materials (open access)

Evidence for the incorporation of lead into barite from waste rock pile materials

Because Pb is one of the most toxic elements and is found as a major contaminant in mining environments, this study aims to identify the distribution of this element in host phases issued from the alteration of mine wastes. The sampling location was a former mine near Oakland, California (USA). This mine was once a source of sulfide minerals from which sulfuric acid was made. The material discussed in this paper was collected in iron hardpans that were formed within the waste rock pile resulting from the excavation work. In most contaminated environments (soils, mine waste), secondary metal-bearing phases arising from alteration processes are usually fine-grained (from 10 {micro}m to less than 1 {micro}m) and highly heterogeneous, requiring the use of micron-scale techniques. We performed micro-Raman spectroscopy, microscanning X-ray diffraction (SXRD), and microextended X-ray near edge spectroscopy (XANES) to determine the relationships between Pb and a Ba/Fe-rich host phase. Micro-Raman spectroscopy suggests that Pb is preferentially incorporated into barite rather than goethite. Results from micro-Raman experiments show the high sensitivity of this analytical tool to the incorporation of Pb into barite by being especially sensitive to the variations of the S-O bond and showing the characteristic bands due to the …
Date: January 21, 2008
Creator: COURTIN-NOMADE, ALEXANDRA; SOUBRAND-COLIN, MARILYNE; MARCUS, MATTHEW A. & FAKRA, SIRINE .C
Object Type: Article
System: The UNT Digital Library
Fast Soft X-ray Images of MHD Phenomena in NSTX (open access)

Fast Soft X-ray Images of MHD Phenomena in NSTX

A variety of MHD phenomena have been observed on NSTX. Many of these affect fast particle losses, which are of major concern for future burning plasma experiments. Usual diagnostics for studying these phenomena are arrays of Mirnov coils for magnetic oscillations and PIN diode arrays for soft x-ray emission from the plasma core. Data reported here are from an unique fast soft x-ray imaging camera (FSXIC) with a wide-angle (pinhole) tangential view of the entire plasma minor cross section. The camera provides a 64x64 pixel image, on a CCD chip, of light resulting from conversion of soft x-rays incident on a phosphor to the visible. We have acquired plasma images at frame rates of 1-500 kHz (300 frames/shot), and have observed a variety of MHD phenomena: disruptions, sawteeth, fishbones, tearing modes, and ELMs. New data including modes with frequency > 90 kHz are also presented. Data analysis and modeling techniques used to interpret the FSXIC data are described and compared, and FSXIC results are compared to Mirnov and PIN diode array results.
Date: July 21, 2008
Creator: C.E. Bush, B.C. Stratton, J. Robinson, L.E. Zakharov, E. D. Fredrickson, D. Stutman, K. Tritz
Object Type: Article
System: The UNT Digital Library
Atmospheric Inverse Estimates of Methane Emissions from Central California (open access)

Atmospheric Inverse Estimates of Methane Emissions from Central California

Methane mixing ratios measured at a tall-tower are compared to model predictions to estimate surface emissions of CH{sub 4} in Central California for October-December 2007 using an inverse technique. Predicted CH{sub 4} mixing ratios are calculated based on spatially resolved a priori CH{sub 4} emissions and simulated atmospheric trajectories. The atmospheric trajectories, along with surface footprints, are computed using the Weather Research and Forecast (WRF) coupled to the Stochastic Time-Inverted Lagrangian Transport (STILT) model. An uncertainty analysis is performed to provide quantitative uncertainties in estimated CH{sub 4} emissions. Three inverse model estimates of CH{sub 4} emissions are reported. First, linear regressions of modeled and measured CH{sub 4} mixing ratios obtain slopes of 0.73 {+-} 0.11 and 1.09 {+-} 0.14 using California specific and Edgar 3.2 emission maps respectively, suggesting that actual CH{sub 4} emissions were about 37 {+-} 21% higher than California specific inventory estimates. Second, a Bayesian 'source' analysis suggests that livestock emissions are 63 {+-} 22% higher than the a priori estimates. Third, a Bayesian 'region' analysis is carried out for CH{sub 4} emissions from 13 sub-regions, which shows that inventory CH{sub 4} emissions from the Central Valley are underestimated and uncertainties in CH{sub 4} emissions are reduced …
Date: November 21, 2008
Creator: Zhao, Chuanfeng; Andrews, Arlyn E.; Bianco, Laura; Eluszkiewicz, Janusz; Hirsch, Adam; MacDonald, Clinton et al.
Object Type: Article
System: The UNT Digital Library
Mechanical Devices Readiness FY04.0402.3 (open access)

Mechanical Devices Readiness FY04.0402.3

This project funded production process and tooling improvements to meet and sustain rate production for the W76-1 mechanism assemblies. Techniques were developed to allow evaluation and disposition of sealed stronglinks that resulted in prevention of the scrapping of numerous stronglinks and firesets. Improved processes and tooling allowed D-Test rates to be reduced in favor of E-Test, thus saving millions of dollars over the life of the program. Future system mechanisms will likely be smaller with tighter toleranced parts that will require improved inspection equipment and techniques. During the latter phase of this project, a method of improving inspection was developed that will have benefits for existing and future system mechanical assemblies.
Date: October 21, 2008
Creator: Fitzgerald, John M.
Object Type: Report
System: The UNT Digital Library
Pressure-temperature stability studies of FeOOH using x-ray diffraction (open access)

Pressure-temperature stability studies of FeOOH using x-ray diffraction

The Mie-Gruneisen formalism is used to fit a Birch-Murnaghan equation of state to high-temperature (T), high-pressure (P) X-ray diffraction unit-cell volume (V) measurements on synthetic goethite (alpha-FeOOH) to combined conditions of T = 23-250o C and P = 0-29.4 GPa. We find the zero-pressure thermal expansion coefficient of goethite to be alpha0 = 2.3 (+-0.6) x 10-5 K-1 over this temperature range. Our data yield zero-pressure compressional parameters: V0 = 138.75 (+- 0.02) Angstrom3, bulk modulus K0 = 140.3 (+- 3.7) GPa, pressure derivative K0' = 4.6 (+- 0.4), Gruneisen parameter gamma0 = 0.91 (+- 0.07), and Debye temperature Theta0 = 740 (+- 5) K. We identify decomposition conditions for 2alpha-FeOOH --> alpha-Fe2O3 + H2O at 1 - 8 GPa and 100-400oC, and the polymorphic transition from alpha-FeOOH (Pbnm) to epsilon-FeOOH (P21mn). The non-quenchable, high-pressure epsilon-FeOOH phase P-V data are fitted to a second-order (Birch) equation of state yielding, K0 = 158 (+- 5) GPa and V0 = 66.3 (+- 0.5) Angstrom3.
Date: July 21, 2008
Creator: Gleason, Arianna E.; Jeanloz, Raymond & Kunz, Martin
Object Type: Article
System: The UNT Digital Library
Electron Bernstein Wave Emission and Mode Conversion Physics on NSTX (open access)

Electron Bernstein Wave Emission and Mode Conversion Physics on NSTX

NSTX is a spherical tokamak (ST) that operates with ne up to 1020 m-3 and BT less than 0.6 T, cutting off low harmonic electron cyclotron (EC) emission widely used for Te measurements on conventional aspect ratio tokamaks. The electron Bernstein wave (EBW) can propagate in ST plasmas and is emitted at EC harmonics. These properties suggest thermal EBW emission (EBE) may be used for local Te measurements in the ST. Practically, a robust Te(R,t) EBE diagnostic requires EBW transmission efficiencies of > 90% for a wide range of plasma conditions. EBW emission and coupling physics were studied on NSTX with an obliquely viewing EBW to O-mode (B-X-O) diagnostic with two remotely steered antennas, coupled to absolutely calibrated radiometers. While Te(R,t) measurements with EBW emission on NSTX were possible, they were challenged by several issues. Rapid fluctuations in edge ne scale length resulted in > 20% changes in the low harmonic B-X-O transmission efficiency. Also, B-X-O transmission efficiency 2 during H-modes was observed to decay by a factor of 5-10 to less than a few percent. The B-X-O transmission behavior during H-modes was reproduced by EBE simulations that predict that EBW collisional damping can significantly reduce emission when Te < …
Date: May 21, 2008
Creator: Diem, S J; Caughman, J B; Efthimion, P; Kugel, H; LeBlanc, B P; Preinhaelter, J et al.
Object Type: Article
System: The UNT Digital Library
DOE EPSCoR Initiative in Structural and computational Biology/Bioinformatics (open access)

DOE EPSCoR Initiative in Structural and computational Biology/Bioinformatics

The overall goal of the DOE EPSCoR Initiative in Structural and Computational Biology was to enhance the competiveness of Vermont research in these scientific areas. To develop self-sustaining infrastructure, we increased the critical mass of faculty, developed shared resources that made junior researchers more competitive for federal research grants, implemented programs to train graduate and undergraduate students who participated in these research areas and provided seed money for research projects. During the time period funded by this DOE initiative: (1) four new faculty were recruited to the University of Vermont using DOE resources, three in Computational Biology and one in Structural Biology; (2) technical support was provided for the Computational and Structural Biology facilities; (3) twenty-two graduate students were directly funded by fellowships; (4) fifteen undergraduate students were supported during the summer; and (5) twenty-eight pilot projects were supported. Taken together these dollars resulted in a plethora of published papers, many in high profile journals in the fields and directly impacted competitive extramural funding based on structural or computational biology resulting in 49 million dollars awarded in grants (Appendix I), a 600% return on investment by DOE, the State and University.
Date: February 21, 2008
Creator: Wallace, Susan S.
Object Type: Report
System: The UNT Digital Library
Cleanup Verification Package for the118-F-2 Burial Ground (open access)

Cleanup Verification Package for the118-F-2 Burial Ground

This cleanup verification package documents completion of remedial action, sampling activities, and compliance with cleanup criteria for the 118-F-2 Burial Ground. This burial ground, formerly called Solid Waste Burial Ground No. 1, was the original solid waste disposal site for the 100-F Area. Eight trenches contained miscellaneous solid waste from the 105-F Reactor and one trench contained solid waste from the biology facilities.
Date: February 21, 2008
Creator: Anselm, J. M. Capron and K. A.
Object Type: Report
System: The UNT Digital Library
DNA repair decline during mouse spermiogenesis results in the accumulation of heritable DNA damage (open access)

DNA repair decline during mouse spermiogenesis results in the accumulation of heritable DNA damage

The post-meiotic phase of mouse spermatogenesis (spermiogenesis) is very sensitive to the genomic effects of environmental mutagens because as male germ cells form mature sperm they progressively lose the ability to repair DNA damage. We hypothesized that repeated exposures to mutagens during this repair-deficient phase result in the accumulation of heritable genomic damage in mouse sperm that leads to chromosomal aberrations in zygotes after fertilization. We used a combination of single or fractionated exposures to diepoxybutane (DEB), a component of tobacco smoke, to investigate how differential DNA repair efficiencies during the three weeks of spermiogenesis affected the accumulation of DEB-induced heritable damage in early spermatids (21-15 days before fertilization, dbf), late spermatids (14-8 dbf) and sperm (7- 1 dbf). Analysis of chromosomalaberrations in zygotic metaphases using PAINT/DAPI showed that late spermatids and sperm are unable to repair DEB-induced DNA damage as demonstrated by significant increases (P<0.001) in the frequencies of zygotes with chromosomal aberrations. Comparisons between single and fractionated exposures suggested that the DNA repair-deficient window during late spermiogenesis may be less than two weeks in the mouse and that during this repair-deficient window there is accumulation of DNA damage in sperm. Finally, the dose-response study in sperm indicated a …
Date: February 21, 2008
Creator: Marchetti, Francesco; Marchetti, Francesco & Wryobek, Andrew J
Object Type: Article
System: The UNT Digital Library
A STRUCTURAL IMPACT ASSESSMENT OF FLAWS DETECTED DURING ULTRASONIC EXAMINATION OF TANK 15 (open access)

A STRUCTURAL IMPACT ASSESSMENT OF FLAWS DETECTED DURING ULTRASONIC EXAMINATION OF TANK 15

Ultrasonic (UT) inspection of Tank 15 was conducted between April and July 2007 in accordance with the Tank 15 UT inspection plan. This was a planned re-inspection of this tank, the previous one was performed in 2002. Ten cracks were characterized in the previous examination. The re-inspection was performed to verify the present models and understanding for stress corrosion cracking. During this re-examination, one indication that was initially reported as a 'possible perpendicular crack &lt;25% through wall' in 2002, was clearly shown not to be a crack. Additionally, examination of a new area immediately adjacent to other cracks along a vertical weld revealed three new cracks. It is not known when these new cracks formed as they could very well have been present in 2002 as well. Therefore, a total of twelve cracks were evaluated during the re-examination. A critical review of the information describing stress corrosion crack behavior for the SRS waste tanks, as well as a summary review of the service history of Tank 15, was performed. Each crack was then evaluated for service exposure history, consistency of the crack behavior with the current understanding of stress corrosion cracking, and present and future impact to the structural integrity …
Date: August 21, 2008
Creator: Wiersma, B & James Elder, J
Object Type: Report
System: The UNT Digital Library
DEVELOPMENT OF VADOSE-ZONE HYDRAULIC PARAMETER VALUES (open access)

DEVELOPMENT OF VADOSE-ZONE HYDRAULIC PARAMETER VALUES

Several approaches have been developed to establish a relation between the soil-moisture retention curve and readily available soil properties. Those relationships are referred to as pedotransfer functions. Described in this paper are the rationale, approach, and corroboration for use of a nonparametric pedotransfer function for the estimation of soil hydraulic-parameter values at the yucca Mountain area in Nevada for simulations of net infiltration. This approach, shown to be applicable for use at Yucca Mountain, is also applicable for use at the Hanford Site where the underlying data were collected.
Date: January 21, 2008
Creator: PM, ROGERS
Object Type: Article
System: The UNT Digital Library
Center-stabilized Yang-Mills Theory:Confinement and Large N Volume Independence (open access)

Center-stabilized Yang-Mills Theory:Confinement and Large N Volume Independence

We examine a double trace deformation of SU(N) Yang-Mills theory which, for large N and large volume, is equivalent to unmodified Yang-Mills theory up to O(1/N{sup 2}) corrections. In contrast to the unmodified theory, large N volume independence is valid in the deformed theory down to arbitrarily small volumes. The double trace deformation prevents the spontaneous breaking of center symmetry which would otherwise disrupt large N volume independence in small volumes. For small values of N, if the theory is formulated on R{sup 3} x S{sup 1} with a sufficiently small compactification size L, then an analytic treatment of the non-perturbative dynamics of the deformed theory is possible. In this regime, we show that the deformed Yang-Mills theory has a mass gap and exhibits linear confinement. Increasing the circumference L or number of colors N decreases the separation of scales on which the analytic treatment relies. However, there are no order parameters which distinguish the small and large radius regimes. Consequently, for small N the deformed theory provides a novel example of a locally four-dimensional pure gauge theory in which one has analytic control over confinement, while for large N it provides a simple fully reduced model for Yang-Mills theory. …
Date: March 21, 2008
Creator: Unsal, Mithat; /SLAC /Stanford U., Phys. Dept.; Yaffe, Laurence G. & /Washington U., Seattle
Object Type: Article
System: The UNT Digital Library