CHEMICAL SAFETY: ASKING THE RIGHT QUESTIONS (open access)

CHEMICAL SAFETY: ASKING THE RIGHT QUESTIONS

Recent reports have shown that, despite efforts to the contrary, chemical accidents continue to occur at an unacceptable rate and there is no evidence that this rate is decreasing. Based on this observation, one can conclude that previous analyses have not accurately identified and implemented appropriate fixes to eliminate identified root causes for chemical events. Based on this, it is time to reevaluate chemical accident data with a fresh eye and determine (a) what corrective actions have already been identified but have not been implemented, (b) what other root causes may be involved, and (c) what new corrective actions should be taken to eliminate these newly identified root causes.
Date: August 5, 2008
Creator: Simmons, F
Object Type: Article
System: The UNT Digital Library
Compound-Nucleus Formation Following Direct Interactions to Highly-Excited Final States (open access)

Compound-Nucleus Formation Following Direct Interactions to Highly-Excited Final States

When direct reactions populate highly excited, unbound configurations in the residual nucleus, the nucleus may further evolve into a compound nucleus. Alternatively, the residual system may decay by emitting particles into the continuum. Understanding the relative weights of these two processes as a function of the angular momentum and parity deposited in the nucleus is important for the surrogate-reaction technique. A particularly interesting case is compound-nucleus formation via the (d, p) reaction, which may be a useful tool for forming compound nuclei off the valley of stability in inverse-kinematics experiments. We present here a study of the compound formation probability for a closely-related direct reaction, direct-semidirect radiative neutron capture.
Date: February 5, 2008
Creator: Dietrich, F S
Object Type: Article
System: The UNT Digital Library
High Resolution Upgrade of the ATF Damping ring BPM System (open access)

High Resolution Upgrade of the ATF Damping ring BPM System

None
Date: June 5, 2008
Creator: Terunuma, N.; Urakawa, J.; Frisch, J.; May, J.; McCormick, D.; Nelson, J. et al.
Object Type: Article
System: The UNT Digital Library
Abstract: Contaminant Travel Times From the Nevada Test Site to Yucca Mountain: Sensitivity to Porosity (open access)

Abstract: Contaminant Travel Times From the Nevada Test Site to Yucca Mountain: Sensitivity to Porosity

Yucca Mountain (YM), Nevada, has been proposed by the U.S. Department of Energy as a geologic repository for spent nuclear fuel and high-level radioactive waste. In this study, we investigate the potential for groundwater advective pathways from underground nuclear testing areas on the Nevada Test Site (NTS) to the YM area by estimating the timeframe for advective travel and its uncertainty resulting from porosity value uncertainty for hydrogeologic units (HGUs) in the region. We perform sensitivity analysis to determine the most influential HGUs on advective radionuclide travel times from the NTS to the YM area. Groundwater pathways and advective travel times are obtained using the particle tracking package MODPATH and flow results from the Death Valley Regional Flow System (DVRFS) model by the U.S. Geological Survey. Values and uncertainties of HGU porosities are quantified through evaluation of existing site porosity data and expert professional judgment and are incorporated through Monte Carlo simulations to estimate mean travel times and uncertainties. We base our simulations on two steady state flow scenarios for the purpose of long term prediction and monitoring. The first represents pre-pumping conditions prior to groundwater development in the area in 1912 (the initial stress period of the DVRFS model). …
Date: September 5, 2008
Creator: Pohlmann, Karl F.; Zhu, Jianting; Chapman, Jenny B.; Russell, Charles E.; Carroll, Rosemary W. H. & Shafer, David S.
Object Type: Article
System: The UNT Digital Library
A korarchaeal genome reveals insights into the evolution of the Archaea (open access)

A korarchaeal genome reveals insights into the evolution of the Archaea

The candidate division Korarchaeota comprises a group of uncultivated microorganisms that, by their small subunit rRNA phylogeny, may have diverged early from the major archaeal phyla Crenarchaeota and Euryarchaeota. Here, we report the initial characterization of a member of the Korarchaeota with the proposed name,"Candidatus Korarchaeum cryptofilum," which exhibits an ultrathin filamentous morphology. To investigate possible ancestral relationships between deep-branching Korarchaeota and other phyla, we used whole-genome shotgun sequencing to construct a complete composite korarchaeal genome from enriched cells. The genome was assembled into a single contig 1.59 Mb in length with a G + C content of 49percent. Of the 1,617 predicted protein-coding genes, 1,382 (85percent) could be assigned to a revised set of archaeal Clusters of Orthologous Groups (COGs). The predicted gene functions suggest that the organism relies on a simple mode of peptide fermentation for carbon and energy and lacks the ability to synthesize de novo purines, CoA, and several other cofactors. Phylogenetic analyses based on conserved single genes and concatenated protein sequences positioned the korarchaeote as a deep archaeal lineage with an apparent affinity to the Crenarchaeota. However, the predicted gene content revealed that several conserved cellular systems, such as cell division, DNA replication, and tRNA …
Date: June 5, 2008
Creator: Anderson, Iain J; Elkins, James G.; Podar, Mircea; Graham, David E.; Makarova, Kira S.; Wolf, Yuri et al.
Object Type: Article
System: The UNT Digital Library
Single-cycle nonlinear optics (open access)

Single-cycle nonlinear optics

Nonlinear optics plays a central role in the advancement of optical science and laser-based technologies. We report on the confinement of the nonlinear interaction of light with matter to a single wave cycle and demonstrate its utility for time-resolved and strong-field science. The electric field of 3.3-femtosecond, 0.72-micron laser pulses with a controlled and measured waveform ionizes atoms near the crests of the central wave cycle, with ionization being virtually switched off outside this interval. Isolated sub-100-attosecond pulses of extreme ultraviolet light (photon energy {approx} 80 electron volts), containing {approx} 0.5 nanojoule of energy, emerge from the interaction with a conversion efficiency of {approx} 10{sup -6}. These tools enable the study of the precision control of electron motion with light fields and electron-electron interactions with a resolution approaching the atomic unit of time ({approx} 24 attoseconds).
Date: November 5, 2008
Creator: Max-Planck-Institut fur Quantenoptik
Object Type: Article
System: The UNT Digital Library
2007 Nuclear Data Review (open access)

2007 Nuclear Data Review

The results of a review and evaluation of neutron and non-neutron nuclear data published in the scientific literature are presented. The status of new chemical elements is examined. Data on revised values for the isotopic composition of the elements are reviewed and recommended values are presented. Half-lives of very long-lived nuclides are presented, including double beta decay, double electron capture, long-lived alpha decay and long-lived beta decay. Data from new measurements on the very heavy elements (trans-meitnerium elements) are discussed and tabulated. The first observation of the radioactive decay mode of the free neutron is discussed. New measurements that have expanded the neutron drip line for magnesium and aluminum are discussed. Data on recent neutron cross-section and resonance integral measurements are also discussed.
Date: May 5, 2008
Creator: Holden, N. E.
Object Type: Article
System: The UNT Digital Library
Ambient Radon-222 Monitoring in Amargosa Valley, Nevada (open access)

Ambient Radon-222 Monitoring in Amargosa Valley, Nevada

As part of a program to characterize and baseline selected environmental parameters in the region around the proposed repository at Yucca Mountain, Nevada, ambient radon-222 monitoring was conducted in the rural community of Amargosa Valley, the community closest to the proposed repository site. Passive integrating radon monitors and a continuous radon monitoring instrument were deployed adjacent to the Community Environmental Monitoring Program (CEMP) (http://www.cemp.dri.edu/index.html) station located in the Amargosa Valley Community Center near the library. The CEMP station provided real-time ambient gamma exposure and meteorological data used to correct the integrated radon measurements as well as verify meteorological data collected by the continuous radon monitoring instrument. Additionally, different types of environmental enclosures that housed the monitors and instrument were used to determine if particular designs influenced the ambient radon measurements.
Date: June 5, 2008
Creator: Karr, L. H.; Tappen, J. J.; Shafer, D. & Gray, K. J.
Object Type: Article
System: The UNT Digital Library

Educating Consumers: New Content on Diesel Vehicles, Diesel Exhaust Fluid, and Selective Catalytic Reduction Technologies on the AFDC

Presentation covers new content available on the Alternative Fuels and Advanced Vehicle Data Center regarding diesel vehicles, diesel exhaust fluid, and selective catalytic reduction technologies.
Date: August 5, 2008
Creator: Brodt-Giles, D.
Object Type: Presentation
System: The UNT Digital Library
HIGHLY ENRICHED URANIUM BLEND DOWN PROGRAM AT THE SAVANNAH RIVER SITE PRESENT AND FUTURE (open access)

HIGHLY ENRICHED URANIUM BLEND DOWN PROGRAM AT THE SAVANNAH RIVER SITE PRESENT AND FUTURE

The Department of Energy (DOE) and Tennessee Valley Authority (TVA) entered into an Interagency Agreement to transfer approximately 40 metric tons of highly enriched uranium (HEU) to TVA for conversion to fuel for the Browns Ferry Nuclear Power Plant. Savannah River Site (SRS) inventories included a significant amount of this material, which resulted from processing spent fuel and surplus materials. The HEU is blended with natural uranium (NU) to low enriched uranium (LEU) with a 4.95% 235U isotopic content and shipped as solution to the TVA vendor. The HEU Blend Down Project provided the upgrades needed to achieve the product throughput and purity required and provided loading facilities. The first blending to low enriched uranium (LEU) took place in March 2003 with the initial shipment to the TVA vendor in July 2003. The SRS Shipments have continued on a regular schedule without any major issues for the past 5 years and are due to complete in September 2008. The HEU Blend program is now looking to continue its success by dispositioning an additional approximately 21 MTU of HEU material as part of the SRS Enriched Uranium Disposition Project.
Date: June 5, 2008
Creator: Magoulas, V; Charles Goergen, C & Ronald Oprea, R
Object Type: Article
System: The UNT Digital Library
Scintillation and Luminescence Properties of Undoped and Cerium-doped LiGdCl4 and NaGdCl4 (open access)

Scintillation and Luminescence Properties of Undoped and Cerium-doped LiGdCl4 and NaGdCl4

We report the scintillation properties of the undoped and cerium-doped variations of LiGdCl4 and NaGdCl4. Powder samples of these materials exhibit significant scintillation under X-rays. The samples were synthesized by solid-state methods from a 1:1 molar ratio of lithium or sodium chloride and gadolinium chloride. Cerium trichloride was used as the dopant. The physical, optical, and scintillation properties of these materials were analyzed by powder X-ray diffraction, photoluminescence, X-ray excited luminescence, and pulsed X-ray luminosity measurements. Increases in light yields are observed as the concentration of cerium increases. The highest light yields occurred at 20 percent cerium doping for both compounds. At larger concentrations neither compound formed, indicating a breakdown of the lattice with the addition of large amounts of cerium cations. At 20 percent cerium, LiGdCl4 and NaGdCl4 display scintillation light 3.6 times and 2.2 times the light yield of the reference material, YAlO3:Ce3+, respectively. Both emit in the ranges of 340 ? 350 nm and 365 - 370 nm and display multiexponential decays with cerium-like decay components at 33 ns (LiGdCl4:Ce) and 26 ns (NaGdCl4:Ce).
Date: October 5, 2008
Creator: Porter-Chapman, Yetta D.; Bourret-Courchesne, Edith D.; Bizarri, Gregory; Weber, Marvin J. & Derenzo, Stephen E.
Object Type: Article
System: The UNT Digital Library
PHASE I SINGLE CELL ELECTROLYZER TEST RESULTS (open access)

PHASE I SINGLE CELL ELECTROLYZER TEST RESULTS

This document reports the results of Phase I Single Cell testing of an SO{sub 2}-Depolarized Water Electrolyzer. Testing was performed primarily during the first quarter of FY 2008 at the Savannah River National Laboratory (SRNL) using an electrolyzer cell designed and built at SRNL. Other facility hardware were also designed and built at SRNL. This test further advances this technology for which work began at SRNL in 2005. This research is valuable in achieving the ultimate goal of an economical hydrogen production process based on the Hybrid Sulfur (HyS) Cycle. The focus of this work was to conduct single cell electrolyzer tests to further develop the technology of SO{sub 2}-depolarized electrolysis as part of the HyS Cycle. The HyS Cycle is a hybrid thermochemical cycle that may be used in conjunction with advanced nuclear reactors or centralized solar receivers to produce hydrogen by water-splitting. Like all other sulfur-based cycles, HyS utilizes the high temperature thermal decomposition of sulfuric acid to produce oxygen and regenerate sulfur dioxide. The unique aspect of HyS is the generation of hydrogen in a water electrolyzer that is operated under conditions where dissolved sulfur dioxide depolarizes the anodic reaction, resulting in substantial voltage reduction. Low cell …
Date: August 5, 2008
Creator: Steimke, J & Timothy Steeper, T
Object Type: Report
System: The UNT Digital Library
Dynamic Characterizations of an 8-frame Half-Strip High-speed X-ray Microchannel Plate Imager (open access)

Dynamic Characterizations of an 8-frame Half-Strip High-speed X-ray Microchannel Plate Imager

High-speed microchannel plate (MCP)–based imagers are critical detectors for x-ray diagnostics employed on Z-experiments at Sandia National Laboratories (SNL) to measure time-resolved x-ray spectra and to image dynamic hohlraums. A multiframe design using eight half strips in one imager permits recordings of radiation events in discrete temporal snapshots to yield a time-evolved movie. We present data using various facilities to characterize the performance of this design. These characterization studies include DC and pulsed-voltage biased measurements in both saturated and linear operational regimes using an intense, short-pulsed UV laser. Electrical probe measurements taken to characterize the shape of the HV pulse propagating across the strips help to corroborate the spatial gain dependence.
Date: September 5, 2008
Creator: Ken Moy, Ming Wu, Craig Kruschwitz, Aric Tibbits, Matt Griffin, Greg Rochau
Object Type: Article
System: The UNT Digital Library
Performance of a Buried Radioactive High Level Waste Glass After 24 Years (open access)

Performance of a Buried Radioactive High Level Waste Glass After 24 Years

A radioactive high level waste glass was made in 1980 with Savannah River Site (SRS) Tank 15 waste. This glass was buried in the SRS burial ground for 24 years but lysimeter data was only available for the first 8 years. The glass was exhumed and analyzed in 2004. The glass was predicted to be very durable and laboratory tests confirmed the durability response. The laboratory results indicated that the glass was very durable as did analysis of the lysimeter data. Scanning electron microscopy of the glass burial surface showed no significant glass alteration consistent with the results of the laboratory and field tests. No detectable Pu, Am, Cm, Np, or Ru leached from the glass into the surrounding sediment. Leaching of {beta}/{delta} from {sup 90}Sr and {sup 137}Cs in the glass was diffusion controlled. Less than 0.5% of the Cs and Sr in the glass leached into the surrounding sediment, with >99% of the leached radionuclides remaining within 8 centimeters of the glass pellet.
Date: May 5, 2008
Creator: Jantzen, Carol M.; Kaplan, Daniel J.; Bibler, Ned E.; Peeler, David K. & Plodinec, M. J.
Object Type: Article
System: The UNT Digital Library
Local Two-Photon Couplings and the J=0 Fixed Pole in Real and Virtual Compton Scattering (open access)

Local Two-Photon Couplings and the J=0 Fixed Pole in Real and Virtual Compton Scattering

The local coupling of two photons to the fundamental quark currents of a hadron gives an energy-independent contribution to the Compton amplitude proportional to the charge squared of the struck quark, a contribution which has no analog in hadron scattering reactions. We show that this local contribution has a real phase and is universal, giving the same contribution for real or virtual Compton scattering for any photon virtuality and skewness at fixed momentum transfer squared t. The t-dependence of this J = 0 fixed Regge pole is parameterized by a yet unmeasured even charge-conjugation form factor of the target nucleon. The t = 0 limit gives an important constraint on the dependence of the nucleon mass on the quark mass through the Weisberger relation. We discuss how this 1=x form factor can be extracted from high energy deeply virtual Compton scattering and examine predictions given by models of the H generalized parton distribution.
Date: December 5, 2008
Creator: Brodsky, Stanley J.; Llanes-Estrada, Felipe J. & Szczepaniak, Adam P.
Object Type: Article
System: The UNT Digital Library
Adjustable Shock Test Sled for Haversine Pulses at 250 fps (open access)

Adjustable Shock Test Sled for Haversine Pulses at 250 fps

New test requirements were developed by Sandia National Laboratory to simulate a regime of shock testing not previously performed at the Kansas City Plant operated by Honeywell Federal Manufacturing & Technologies. These environments were unique in that they involved amplitude of shock >1000g with relatively long pulse durations (greater 5 ms but less than 10 ms) and involved velocity changes up to 235 ft/sec. Ten months were available to develop, design, manufacture and prove-in this new capability. We designed a new shock sled to deliver this new family of shock environments in a laboratory test. The performance range of the new sled includes five specific shocks (1000 g – 8 ms, 1300 - 6 ms, 1500 g – 5.4 ms, 1950 g – 6 ms, 2250 g – 5.4 ms; all haversine shaped), and it also incorporates adjustability to accommodate new shocks within this range. These shock environments result in velocity changes ranging from 160 fps to 250 fps. The test sled accommodates test articles weighing up to 20 lbs and measuring up to 10” along any axis.
Date: May 5, 2008
Creator: Hartwig, Troy; Hower, Brent & Seaholm, Aaron
Object Type: Article
System: The UNT Digital Library
Further Dosimetry Studies at Rhode Island Nuclear Science Center. (open access)

Further Dosimetry Studies at Rhode Island Nuclear Science Center.

The RINSC is a 2 mega-watt, light water and graphite moderated and cooled reactor that has a graphite thermal column built as a user facility for sample irradiation. Over the past decade, after the reactor conversion from a highly-enriched uranium core to a low-enriched one, flux and dose measurements and calculations had been performed in the thermal column to update the ex-core parameters and to predict the effect from in-core fuel burn-up and rearrangement. The most recent data from measurements and calculations that have been made at the RINSC thermal column since October of 2005 are reported.
Date: May 5, 2008
Creator: Reciniello, R. N.; Holden, N. E.; Hu, J. P.; Johnson, D. G.; Meddleton, M. & Tehan, T. N.
Object Type: Article
System: The UNT Digital Library
Electrochromically switched, gas-reservoir metal hydride devices with application to energy-efficient windows (open access)

Electrochromically switched, gas-reservoir metal hydride devices with application to energy-efficient windows

Proof-of-principle gas-reservoir MnNiMg electrochromic mirror devices have been investigated. In contrast to conventional electrochromic approaches, hydrogen is stored (at low concentration) in the gas volume between glass panes of the insulated glass units (IGUs). The elimination of a solid state ion storage layer simplifies the layer stack, enhances overall transmission, and reduces cost. The cyclic switching properties were demonstrated and system durability improved with the incorporation a thin Zr barrier layer between the MnNiMg layer and the Pd catalyst. Addition of 9 percent silver to the palladium catalyst further improved system durability. About 100 full cycles have been demonstrated before devices slow considerably. Degradation of device performance appears to be related to Pd catalyst mobility, rather than delamination or metal layer oxidation issues originally presumed likely to present significant challenges.
Date: May 5, 2008
Creator: Anders, Andre; Slack, Jonathan L. & Richardson, Thomas J.
Object Type: Article
System: The UNT Digital Library
Measurement of B \to X \gamma Decays and Determination of |V_{td}/V_{ts}| (open access)

Measurement of B \to X \gamma Decays and Determination of |V_{td}/V_{ts}|

Using a sample of 383 million B{bar B} events collected by the BABAR experiment, they measure sums of seven exclusive final states B {yields} X{sub d(s)}{gamma}, where X{sub d}(X{sub s}) is a non-strange (strange) charmless hadronic system in the mass range 0.6-1.8 GeV/c{sup 2}. After correcting for unmeasured decay modes in this mass range, they obtain a branching fraction for b {yields} d{gamma} of (7.2 {+-} 2.7(stat.) {+-} 2.3(syst.)) x 10{sup -6}. Taking the ratio of X{sub d} to X{sub s} they find {Lambda}(b {yields} d{gamma})/{Lambda}(b {yields} s{gamma}) = 0.033 {+-} 0.013(stat.) {+-} 0.009(syst.), from which they determine |V{sub td}/V{sub ts}| = 0.177 {+-} 0.043.
Date: August 5, 2008
Creator: Collaboration, The BABAR & Aubert, B.
Object Type: Article
System: The UNT Digital Library
Report on Qiagen Columns with Precipitation versus Packed Bed Technology for Trace Amounts of DNA (open access)

Report on Qiagen Columns with Precipitation versus Packed Bed Technology for Trace Amounts of DNA

The assured limit of detection (LOD), where 100% of the PCR assays are successful, for the Qiagen spin column is dramatically improved when combined with an ethanol precipitation step of the eluted sample. A detailed SOP for the ethanol precipitation was delivered as a separate report. A key finding in the precipitation work was to incubate the ethanol precipitation at -20{sup o}C overnight when concentrating low copy number samples. Combining this modified ethanol precipitation with the Qiagen spin columns, the limit of assured detection was improved by 1-2 orders of magnitude, for the aliquot and assay variables used. The lower limit of detection (defined as when at least 1 assay of 1 aliquot was positive) was only improved by approximately 1 order of magnitude. The packed bed process has the potential of a 20-fold improvement in the limit of detection compared to Qiagen plus precipitation, based on a mass balance analysis for the entire DNA concentration and purification processes. Figure ES1 shows a mass balance for all the DNA processing steps. The packed bed process minimizes losses from elution, precipitation, and pipetting (aliquoting and transferring). Figure ES1 assumes that 100 copies of DNA serve as the input sample. Efficiencies for …
Date: February 5, 2008
Creator: Wheeler, E. K.; Erler, A. M. & Seiler, A.
Object Type: Report
System: The UNT Digital Library
Fundamental Investigations of Nanoscale Phenomena in Beam-Assisted Nucleation, Growth and Surface Smoothing, Using in situ LEEM (open access)

Fundamental Investigations of Nanoscale Phenomena in Beam-Assisted Nucleation, Growth and Surface Smoothing, Using in situ LEEM

The purposes for which this grant was provided were specifically (1) to construct a tandem instrument that combined a low energy electron microscope (LEEM) with an ion beam source capably of irradiating a sample during observation of the surface using LEEM; and (2) to employ the new machine to whatever degree possible to observe the evolution of clean crystal surfaces during ion beam irradiation. A principal motivation was to investigate the fundamental behavior of radiation damage under circumstances for which the damage can be observed directly in real time as it occurs. A second main motivation was to create tunable perturbations of the defect (adatom and advacancy) equilibrium on clean crystal planes and in this way explore the fundamental kinetics of surface behavior that enters into numerous phenomena of interest to DOE including surface erosion, catalysis, and the damage to crystals caused by impacts of energetic particles. The funding has been employed to successfully pursue all the original goals, and additional opportunities that developed as a result of discoveries made in this research.
Date: November 5, 2008
Creator: Flynn, Colin P.
Object Type: Text
System: The UNT Digital Library
Search for Invisible Decays of a Light Scalar in Radiative Transitions Y(3S)->gamma A0 (open access)

Search for Invisible Decays of a Light Scalar in Radiative Transitions Y(3S)->gamma A0

We search for a light scalar particle produced in single-photon decays of the {Upsilon}(3S) resonance through the process {Upsilon}(3S) {yields} {gamma} + A{sup 0}, A{sup 0} {yields} invisible. Such an object appears in Next-to-Minimal Supersymmetric extensions of the Standard Model, where a light CP-odd Higgs boson naturally couples strongly to b-quarks. If, in addition, there exists a light, stable neutralino, decays of A{sup 0} could be preferentially to an invisible final state. We search for events with a single high-energy photon and a large missing mass, consistent with a 2-body decay of {Upsilon}(3S). We find no evidence for such processes in a sample of 122 x 10{sup 6} {Upsilon}(3S) decays collected by the BABAR collaboration at the PEP-II B-factory, and set 90% C.L. upper limits on the branching fraction {Beta}({Upsilon}(3S) {yields} {gamma}A{sup 0}) x {Beta}(A{sup 0} {yields} invisible) at (0.7-31) x 10{sup -6} in the mass range m{sub A{sup 0}} {le} 7.8 GeV. The results are preliminary.
Date: November 5, 2008
Creator: Aubert, B.
Object Type: Article
System: The UNT Digital Library
Holographic Systematics of D-brane Inflation (open access)

Holographic Systematics of D-brane Inflation

We provide a systematic treatment of possible corrections to the inflaton potential for D-brane inflation in the warped deformed conifold. We consider the D3-brane potential in the presence of the most general possible corrections to the throat geometry sourced by coupling to the bulk of a compact Calabi-Yau space. This corresponds to the potential on the Coulomb branch of the dual gauge theory, in the presence of arbitrary perturbations of the Lagrangian. The leading contributions arise from perturbations by the most relevant operators that do not destroy the throat geometry. We find a generic contribution from a non-chiral operator of dimension {Delta} = 2 associated with a global symmetry current, resulting in a negative contribution to the inflaton mass-squared. If the Calabi-Yau preserves certain discrete symmetries, this is the dominant correction to the inflaton potential, and fine-tuning of the inflaton mass is possible. In the absence of such discrete symmetries, the dominant contribution comes from a chiral operator with {Delta} = 3/2, corresponding to a {phi}{sup 3/2} term in the inflaton potential. The resulting inflationary models are phenomenologically identical to the inflection point scenarios arising from specific D7-brane embeddings, but occur under far more general circumstances. Our strategy extends immediately …
Date: November 5, 2008
Creator: Baumann, Daniel; /Harvard U., Phys. Dept. /Princeton U.; Dymarsky, Anatoly; /Stanford U., Phys. Dept.; Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC et al.
Object Type: Article
System: The UNT Digital Library
Drilling, Sampling, and Well-Installation Plan for the IFC Well Field, 300 Area (open access)

Drilling, Sampling, and Well-Installation Plan for the IFC Well Field, 300 Area

The 300 Area was selected as a location for an IFC because it offers excellent opportunities for field research on the influence of mass-transfer processes on uranium in the vadose zone and groundwater. The 300 Area was the location of nuclear fuel fabrication facilities and has more than 100 waste sites. Two of these waste sites, the North and South Process Ponds received large volumes of process waste from 1943 to 1975 and are thought to represent a significant source of the groundwater uranium plume in the 300 Area. Geophysical surveys and other characterization efforts have led to selection of the South Process Pond for the IFC.
Date: May 5, 2008
Creator: Bjornstad, Bruce N. & Horner, Jacob A.
Object Type: Report
System: The UNT Digital Library