Nuclear Electric Dipole Moment of 3He (open access)

Nuclear Electric Dipole Moment of 3He

A permanent electric dipole moment (EDM) of a physical system would require time-reversal (T) violation, which is equivalent to charge-conjugation-parity (CP) violation by CPT invariance. Experimental programs are currently pushing the limits on EDMs in atoms, nuclei, and the neutron to regimes of fundamental theoretical interest. Nuclear EDMs can be studied at ion storage rings with sensitivities that may be competitive with atomic and neutron measurements. Here we calculate the magnitude of the CP-violating EDM of {sup 3}He and the expected sensitivity of such a measurement to the underlying CP-violating interactions. Assuming that the coupling constants are of comparable magnitude for {pi}-, {rho}-, and {omega}-exchanges, we find that the pion-exchange contribution dominates. Finally, our results suggest that a measurement of the {sup 3}He EDM is complementary to the planned neutron and deuteron experiments, and could provide a powerful constraint for the theoretical models of the pion-nucleon P,T-violating interaction.
Date: April 8, 2008
Creator: Stetcu, I; P.Liu, C; Friar, J L; Hayes, A C & Navratil, P
System: The UNT Digital Library
Supercomputers: Super-polluters? (open access)

Supercomputers: Super-polluters?

Thanks to imperatives for limiting waste heat, maximizing performance, and controlling operating cost, energy efficiency has been a driving force in the evolution of supercomputers. The challenge going forward will be to extend these gains to offset the steeply rising demands for computing services and performance.
Date: April 8, 2008
Creator: Mills, Evan; Mills, Evan; Tschudi, William; Shalf, John & Simon, Horst
System: The UNT Digital Library
Progress of the PEP-II B-Factory (open access)

Progress of the PEP-II B-Factory

None
Date: April 8, 2008
Creator: Seeman, J.; Browne, Michael C.; Cai, Y.; Colocho, W.; Decker, F.J.; Donald, M. et al.
System: The UNT Digital Library
Study of B to X(3872)K, with X(3872) to J/Psi pi+ pi- (open access)

Study of B to X(3872)K, with X(3872) to J/Psi pi+ pi-

None
Date: April 8, 2008
Creator: Aubert, B.
System: The UNT Digital Library
HAZARD ANALYSIS SOFTWARE (open access)

HAZARD ANALYSIS SOFTWARE

Washington Safety Management Solutions, LLC developed web-based software to improve the efficiency and consistency of hazard identification and analysis, control selection and classification, and to standardize analysis reporting at Savannah River Site. In the new nuclear age, information technology provides methods to improve the efficiency of the documented safety analysis development process which includes hazard analysis activities. This software provides a web interface that interacts with a relational database to support analysis, record data, and to ensure reporting consistency. A team of subject matter experts participated in a series of meetings to review the associated processes and procedures for requirements and standard practices. Through these meetings, a set of software requirements were developed and compiled into a requirements traceability matrix from which software could be developed. The software was tested to ensure compliance with the requirements. Training was provided to the hazard analysis leads. Hazard analysis teams using the software have verified its operability. The software has been classified as NQA-1, Level D, as it supports the analysis team but does not perform the analysis. The software can be transported to other sites with alternate risk schemes. The software is being used to support the development of 14 hazard analyses. …
Date: April 8, 2008
Creator: Sommer, S & Tinh Tran, T
System: The UNT Digital Library
Exponential Growth, Superradiance, and Tunability of a Seeded Free Electron Laser (open access)

Exponential Growth, Superradiance, and Tunability of a Seeded Free Electron Laser

None
Date: April 8, 2008
Creator: Wu, Juhao; /SLAC; Murphy, James B.; Wang, Xijie; /Brookhaven; Wang, Kelin et al.
System: The UNT Digital Library
Stringy Instantons in IIB Brane Systems (open access)

Stringy Instantons in IIB Brane Systems

None
Date: April 8, 2008
Creator: Kachru, Shamit; Simic, Dusan & /Stanford U., Phys. Dept. /SLAC
System: The UNT Digital Library
SAFETY ANALYSIS OF THE DEMONSTRATION BULK VITRIFICATION SYSTEM (open access)

SAFETY ANALYSIS OF THE DEMONSTRATION BULK VITRIFICATION SYSTEM

None
Date: April 8, 2008
Creator: JP, HARRIS
System: The UNT Digital Library
The Early Optical Brightening in the GRB 071010B (open access)

The Early Optical Brightening in the GRB 071010B

We report the detection of early (60-230 s) optical emission of the gamma-ray burst afterglow of GRB071010B. No significant correlation with the prompt {gamma}-ray emission was found. Our high time-resolution data combining with other measurements within 2 days after the burst indicate that GRB071010B is composed of a weak early brightening ({alpha} {approx} 0.6), probably caused by the peak frequency passing through the optical wavelengths, followed by a decay ({alpha} {approx} -0.51), attributed to continuous energy injection by patchy jets.
Date: April 8, 2008
Creator: Wang, J. H.; Schwamb, M. E.; Huang, K. Y.; Wen, C. Y.; Zhang, Z. W.; Wang, S. Y. et al.
System: The UNT Digital Library
Fracture Permeability Evolution in Rock from the Desert Peak EGS Site (open access)

Fracture Permeability Evolution in Rock from the Desert Peak EGS Site

Fluid flow experiments are being conducted on core specimens of quartz monzonite retrieved from depths of about 1 km at the Desert Peak East EGS site in Churchill County, Nevada. Our immediate goal is to observe permeability evolution in fractures at pressure and temperature conditions appropriate to the Desert Peak geothermal site. Longer term, we aim to evaluate mechanisms that control the evolution of fracture permeability. In the experiments saline water is flowed through an artificial fracture at a constant rate of 0.02 ml/min over a period of several weeks. The constant flow tests are interrupted at selected times for shorter tests in which flow is either stopped or varied between 0 and 2.0 ml/min. The experiments to date were conducted at a confining pressure of 5.5 MPa, pore pressures of 1.38 MPa or 2.07 MPa and temperatures of 167- 169 C. Measurements include differential pressure and electrical resistance across the specimen. The short-term variable flow rate experiments allow us to calculate the effective hydraulic aperture of the fracture at various times during the experiment. Changes in electrical resistivity provide indirect evidence of ongoing mineral dissolution and precipitation processes that are expected to change fracture permeability over time. The early …
Date: April 8, 2004
Creator: Carlson, S. R.; Roberts, J. J.; Detwiler, R. L.; Burton, E. A.; Robertson-Tait, A.; Morris, C. et al.
System: The UNT Digital Library
Sensory Transduction in Microorganisms 2008 Gordon Research Conference (January 2008) (open access)

Sensory Transduction in Microorganisms 2008 Gordon Research Conference (January 2008)

Research into the mechanisms involved in the sensing and responses of microorganisms to changes in their environments is currently very active in a large number of laboratories worldwide. An increasingly wide range of prokaryotic and eukaryotic species are being studied with regard to their sensing of diverse chemical and physical stimuli, including nutrients, toxins, intercellular signaling molecules, redox indicators, light, pressure, magnetic fields, and surface contact, leading to adaptive responses affecting motile behavior, gene expression and/or development. The ease of manipulation of microorganisms has facilitated application of a broad range of techniques that have provided comprehensive descriptions of cellular behavior and its underlying molecular mechanisms. Systems and their molecular components have been probed at levels ranging from the whole organism down to atomic resolution using behavioral analyses; electrophysiology; genetics; molecular biology; biochemical and biophysical characterization; structural biology; single molecule, fluorescence and cryo-electron microscopy; computational modeling; bioinformatics and genomic analyses. Several model systems such as bacterial chemotaxis and motility, fruiting body formation in Myxococcus xanthus, and motility and development in Dictyostelium discoideum have traditionally been a focus of this meeting. By providing a basis for assessment of similarities and differences in mechanisms, understanding of these pathways has advanced the study of …
Date: April 8, 2009
Creator: Stock, Ann M.
System: The UNT Digital Library
HANFORDS HISTORIC B REACTOR PRESENTATION TO PNNL OPEN WORLD FORUM 03/20/2009 (open access)

HANFORDS HISTORIC B REACTOR PRESENTATION TO PNNL OPEN WORLD FORUM 03/20/2009

None
Date: April 8, 2009
Creator: MS, GERBER
System: The UNT Digital Library
Acceleration of Amide Bond Rotation by Encapsulation in the Hydrophobic Interior of a Water-Soluble Supramolecular Assembly (open access)

Acceleration of Amide Bond Rotation by Encapsulation in the Hydrophobic Interior of a Water-Soluble Supramolecular Assembly

The hydrophobic interior cavity of a self-assembled supramolecular assembly exploits the hydrophobic effect for the encapsulation of tertiary amides. Variable temperature 1H NMR experiments reveal that the free energy barrier for rotation around the C-N amide bond is lowered by up to 3.6 kcal/mol upon encapsulation. The hydrophobic cavity of the assembly is able to stabilize the less polar transition state of the amide rotation process. Carbon-13 labeling studies showed that the {sup 13}C NMR carbonyl resonance increases with temperature for the encapsulated amides which suggests that the assembly is able to favor a twisted for of the amide.
Date: April 8, 2008
Creator: Pluth, Michael D.; Bergman, Robert G. & Raymond, Kenneth N.
System: The UNT Digital Library
What can we learn from neutrinoless double beta decay experiments? (open access)

What can we learn from neutrinoless double beta decay experiments?

We assess how well next generation neutrinoless double beta decay and normal neutrino beta decay experiments can answer four fundamental questions. 1) If neutrinoless double beta decay searches do not detect a signal, and if the spectrum is known to be inverted hierarchy, can we conclude that neutrinos are Dirac particles? 2) If neutrinoless double beta decay searches are negative and a next generation ordinary beta decay experiment detects the neutrino mass scale, can we conclude that neutrinos are Dirac particles? 3) If neutrinoless double beta decay is observed with a large neutrino mass element, what is the total mass in neutrinos? 4) If neutrinoless double beta decay is observed but next generation beta decay searches for a neutrino mass only set a mass upper limit, can we establish whether the mass hierarchy is normal or inverted? We base our answers on the expected performance of next generation neutrinoless double beta decay experiments and on simulations of the accuracy of calculations of nuclear matrix elements.
Date: April 8, 2004
Creator: Bahcall, John N.; Murayama, Hitoshi & Pena-Garay, Carlos
System: The UNT Digital Library
Integrated Surface-groundwater Flow Modeling: a Free-surface Overland Flow Boundary Condition in a Parallel Groundwater Flow Model (open access)

Integrated Surface-groundwater Flow Modeling: a Free-surface Overland Flow Boundary Condition in a Parallel Groundwater Flow Model

Interactions between surface and ground water are a key component of the hydrologic budget on the watershed scale. Models that honor these interactions are commonly based on the conductance concept that presumes a distinct interface at the land surface, separating the surface from the subsurface domain. These types of models link the subsurface and surface domains via an exchange flux that depends upon the magnitude and direction of the hydraulic gradient across the interface and a proportionality constant (a measure of the hydraulic connectivity). Because experimental evidence of such a distinct interface is often lacking in field systems, there is a need for a more general coupled modeling approach. A more general coupled model is presented that incorporates a new two-dimensional overland flow simulator into the parallel three-dimensional variable saturated subsurface flow code ParFlow. In ParFlow, the overland flow simulator takes the form of an upper boundary condition and is, thus, fully integrated without relying on the conductance concept. Another important advantage of this approach is the efficient parallelism incorporated into ParFlow, which is efficiently exploited by the overland flow simulator. Several verification and simulation examples are presented that focus on the two main processes of runoff production: excess infiltration …
Date: April 8, 2005
Creator: Kollet, S J & Maxwell, R M
System: The UNT Digital Library
Is U3Ni3Sn4 best described as near a quantum critical point? (open access)

Is U3Ni3Sn4 best described as near a quantum critical point?

Although most known non-Fermi liquid (NFL) materials are structurally or chemically disordered, the role of this disorder remains unclear. In particular, very few systems have been discovered that may be stoichiometric and well ordered. To test whether U{sub 3}Ni{sub 3}Sn{sub 4} belongs in this latter class, we present measurements of the x-ray absorption fine structure (XAFS) of polycrystalline and single-crystal U{sub 3}Ni{sub 3}Sn{sub 4} samples that are consistent with no measurable local atomic disorder. We also present temperature-dependent specific heat data in applied magnetic fields as high as 8 T that show features that are inconsistent with the antiferromagnetic Griffiths' phase model, but do support the conclusion that a Fermi liquid/NFL crossover temperature increases with applied field. These results are inconsistent with theoretical explanations that require strong disorder effects, but do support the view that U{sub 3}Ni{sub 3}Sn{sub 4} is a stoichoiometric, ordered material that exhibits NFL behavior, and is best described as being near an antiferromagnetic quantum critical point.
Date: April 8, 2003
Creator: Booth, C. H.; Shlyk, L.; Nenkov, K.; Huber, J. G. & De Long, L. E.
System: The UNT Digital Library
Seismic imaging of reservoir flow properties: Time-lapse pressurechanges (open access)

Seismic imaging of reservoir flow properties: Time-lapse pressurechanges

Time-lapse fluid pressure and saturation estimates are sensitive to reservoir flow properties such as permeability. In fact, given time-lapse estimates of pressure and saturation changes, one may define a linear partial differential equation for permeability variations within the reservoir. The resulting linear inverse problem can be solved quite efficiently using sparse matrix techniques. An application to a set of crosswell saturation and pressure estimates from a CO{sub 2} flood at the Lost Hills field in California demonstrates the utility of this approach. From the crosswell estimates detailed estimates of reservoir permeability are produced. The resulting permeability estimates agree with a permeability log in an adjacent well and are in accordance with water and CO{sub 2} saturation changes in the interwell region.
Date: April 8, 2003
Creator: Vasco, Don W.
System: The UNT Digital Library
The Ags High Power Upgrade Plan. (open access)

The Ags High Power Upgrade Plan.

BNL could provide a Megawatt class neutrino beam from the AGS for very long baseline neutrino experiments. We have studied two possible approaches to upgrade the AGS to 1.0 MW beam power. The first is the linac option, comprising a new superconducting linac injector of 1.2 GeV, accelerating 9 x 10{sup 3} proton per pulse in the AGS to 28 GeV at 2.5 Hz. The second option is to extend the existing 200 MeV linac to 400 MeV. ramp the Booster to 2.5 GeV at 6 Hz. add a new 2.5 GeV accumulator ring in the AGS tunnel. and finally ramp the AGS to 28 GeV at 2.5 Hz. Due to the simplicity of the linac approach and minimum interference with the on going research program. the linac option is the preferred one.
Date: April 8, 2002
Creator: Weng, W. T. & Roser, T.
System: The UNT Digital Library
Sea Water Radiocarbon Evolution in the Gulf of Alaska: 2002 Observations (open access)

Sea Water Radiocarbon Evolution in the Gulf of Alaska: 2002 Observations

Oceanic uptake and transport of bomb radiocarbon as {sup 14}CO{sub 2} created by atmospheric nuclear weapons testing in the 1950s and 1960s has been a useful diagnostic to determine the carbon transfer between the ocean and atmosphere. In addition, the distribution of radiocarbon in the ocean can be used as a tracer of oceanic circulation. Results obtained from samples collected in the Gulf of Alaska in the summer of 2002 provide a direct comparison with results in the 1970s during GEOSECS and in the early 1990s during WOCE. The open gyre values are 20-40{per_thousand} more negative than those documented in 1991 and 1993 (WOCE) although the general trends as a function of latitude are reproduced. Surface values are still significantly higher than pre-bomb levels ({approx}-105{per_thousand} or lower). In the central gyre, we observe {Delta}{sup 14}C-values that are lower in comparison to GEOSECS (stn 218) and WOCE P16/P17 to a density of {approx}26.8{sigma}t. This observation is consistent with the overall decrease in surface {Delta}{sup 14}C values, and reflects the erosion of the bomb-{sup 14}C transient. We propose that erosion of the bomb-{sup 14}C transient is accomplished by entrainment of low {sup 14}C water via vertical exchange within the Gulf of Alaska …
Date: April 8, 2005
Creator: Guilderson, T. P.; Roark, E. B.; Quay, P. D.; Flood-Page, S. R. & Moy, C.
System: The UNT Digital Library
Pressure diffusion waves in porous media (open access)

Pressure diffusion waves in porous media

Pressure diffusion wave in porous rocks are under consideration. The pressure diffusion mechanism can provide an explanation of the high attenuation of low-frequency signals in fluid-saturated rocks. Both single and dual porosity models are considered. In either case, the attenuation coefficient is a function of the frequency.
Date: April 8, 2003
Creator: Silin, Dmitry; Korneev, Valeri & Goloshubin, Gennady
System: The UNT Digital Library
Orbit: A Code for Collective Beam Dynamics in High Intensity Rings. (open access)

Orbit: A Code for Collective Beam Dynamics in High Intensity Rings.

We are developing a computer code, ORBIT, specifically for beam dynamics calculations in high-intensity rings. Our approach allows detailed simulation of realistic accelerator problems. ORBIT is a particle-in-cell tracking code that transports bunches of interacting particles through a series of nodes representing elements, effects, or diagnostics that occur in the accelerator lattice. At present, ORBIT contains detailed models for strip-foil injection, including painting and foil scattering; rf focusing and acceleration; transport through various magnetic elements; longitudinal and transverse impedances; longitudinal, transverse, and three-dimensional space charge forces; collimation and limiting apertures; and the calculation of many useful diagnostic quantities. ORBIT is an object-oriented code, written in C++ and utilizing a scripting interface for the convenience of the user. Ongoing improvements include the addition of a library of accelerator maps, BEAMLINE/MXYZPTLK, the introduction of a treatment of magnet errors and fringe fields; the conversion of the scripting interface to the standard scripting language, Python; and the parallelization of the computations using MPI. The ORBIT code is an open source, powerful, and convenient tool for studying beam dynamics in high-intensity rings.
Date: April 8, 2002
Creator: Holmes, J. A.; Danilov, V.; Galambos, J.; Shishlo, A.; Cousineau, S.; Chou, W. et al.
System: The UNT Digital Library
Carbon sequestration in natural gas reservoirs: Enhanced gas recovery and natural gas storage (open access)

Carbon sequestration in natural gas reservoirs: Enhanced gas recovery and natural gas storage

Natural gas reservoirs are obvious targets for carbon sequestration by direct carbon dioxide (CO{sub 2}) injection by virtue of their proven record of gas production and integrity against gas escape. Carbon sequestration in depleted natural gas reservoirs can be coupled with enhanced gas production by injecting CO{sub 2} into the reservoir as it is being produced, a process called Carbon Sequestration with Enhanced Gas Recovery (CSEGR). In this process, supercritical CO{sub 2} is injected deep in the reservoir while methane (CH{sub 4}) is produced at wells some distance away. The active injection of CO{sub 2} causes repressurization and CH{sub 4} displacement to allow the control and enhancement of gas recovery relative to water-drive or depletion-drive reservoir operations. Carbon dioxide undergoes a large change in density as CO{sub 2} gas passes through the critical pressure at temperatures near the critical temperature. This feature makes CO{sub 2} a potentially effective cushion gas for gas storage reservoirs. Thus at the end of the CSEGR process when the reservoir is filled with CO{sub 2}, additional benefit of the reservoir may be obtained through its operation as a natural gas storage reservoir. In this paper, we present discussion and simulation results from TOUGH2/EOS7C of gas …
Date: April 8, 2003
Creator: Oldenburg, Curtis M.
System: The UNT Digital Library
Longitudinal Dynamics in High Frequency FFAG Recirculating Accelerators. (open access)

Longitudinal Dynamics in High Frequency FFAG Recirculating Accelerators.

A recirculating accelerator accelerates the beam by passing through accelerating cavities multiple times. An FFAG recirculating accelerator uses a single arc to connect the linacs together, as opposed to multiple arcs for the different energies. For most scenarios using high-frequency RF, it is impractical to change the phase of the RF on each pass, at least for lower energy accelerators. Ideally, therefore, the WAG arc will be isochronous, so that the particles come back to the same phase (on-crest) on each linac pass. However, it is not possible to make the FFAG arcs isochronous (compared to the RF period) over a large energy range. This paper demonstrates that one can nonetheless make an WAG recirculating accelerator work. Given the arc's path length as a function of energy and the number of turns to accelerate for, one can find the minimum voltage (and corresponding initial conditions) required to accelerate a reference particle to the desired energy. I also briefly examine how the longitudinal acceptance varies with the number of turns that one accelerates.
Date: April 8, 2002
Creator: Berg, J. S.
System: The UNT Digital Library
Steady State Creep of Zirconium at High and Intermediate Temperatures (open access)

Steady State Creep of Zirconium at High and Intermediate Temperatures

Creep of zirconium and zirconium alloys has been labeled ''anomalous.'' Researchers often report that zirconium and its alloys never reach true steady state creep and have stress exponents that continuously change with stress and temperature. Many varied interpretations have been offered explaining the creep behavior of zirconium. Some have suggested that creep is diffusion controlled, while others maintain that creep is dislocation glide controlled. Cumulative zirconium creep data will be presented based on an extensive literature review. An interpretation of results will be presented and compared to previous interpretations.
Date: April 8, 2000
Creator: Rosen, R.S. & Hayes, T.A.
System: The UNT Digital Library