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Hydrodynamick instabilities on ICF capsules (open access)

Hydrodynamick instabilities on ICF capsules

This article summarizes our current understanding of hydrodynamic instabilities as relevant to ICF. First we discuss classical, single mode Rayleigh-Taylor instability, and nonlinear effects in the evolution of a single mode. Then we discuss multimode systems, considering: (1) the onset of nonlinearity; (2) a second order mode coupling theory for weakly nonlinear effects, and (3) the fully nonlinear regime. Two stabilization mechanisms relevant to ICF are described next: gradient scale length and convective stabilization. Then we describe a model which is meant to estimate the weakly nonlinear evolution of multi-mode systems as relevant to ICF, given the short-wavelength stabilization. Finally, we discuss the relevant code simulation capability, and experiments. At this time we are quite optimistic about our ability to estimate instability growth on ICF capsules, but further experiments and simulations are needed to verify the modeling. 52 refs.
Date: June 7, 1991
Creator: Haan, S.W.
System: The UNT Digital Library
Effective theories and thresholds in particle physics (open access)

Effective theories and thresholds in particle physics

The role of effective theories in probing a more fundamental underlying theory and in indicating new physics thresholds is discussed, with examples from the standard model and more speculative applications to superstring theory. 38 refs.
Date: June 7, 1991
Creator: Gaillard, M. K.
System: The UNT Digital Library
Enhanced geothermal systems (EGS) using CO2 as working fluid - Anovelapproach for generating renewable energy with simultaneoussequestration of carbon (open access)

Enhanced geothermal systems (EGS) using CO2 as working fluid - Anovelapproach for generating renewable energy with simultaneoussequestration of carbon

Responding to the need to reduce atmospheric emissions of carbon dioxide, Donald Brown (2000) proposed a novel enhanced geothermal systems (EGS) concept that would use CO{sub 2} instead of water as heat transmission fluid, and would achieve geologic sequestration of CO{sub 2} as an ancillary benefit. Following up on his suggestion, we have evaluated thermophysical properties and performed numerical simulations to explore the fluid dynamics and heat transfer issues in an engineered geothermal reservoir that would be operated with CO{sub 2}. We find that CO{sub 2} is superior to water in its ability to mine heat from hot fractured rock. CO{sub 2} also has certain advantages with respect to wellbore hydraulics, where larger compressibility and expansivity as compared to water would increase buoyancy forces and would reduce the parasitic power consumption of the fluid circulation system. While the thermal and hydraulic aspects of a CO{sub 2}-EGS system look promising, major uncertainties remain with regard to chemical interactions between fluids and rocks. An EGS system running on CO{sub 2} has sufficiently attractive features to warrant further investigation.
Date: June 7, 2006
Creator: Pruess, Karsten
System: The UNT Digital Library
Sensor Development for the Large Synoptic Survey Telescope. (open access)

Sensor Development for the Large Synoptic Survey Telescope.

The Large Synoptic Survey project proposes to build an 8m-class ground-based telescope with a dedicated wide field camera. The camera consists of a large focal plane mosaic composed of multi-output CCDs with extended red response. Design considerations and preliminary characterization results for the sensors are presented in this contribution to the Workshop.
Date: June 7, 2007
Creator: O'Connor, P.; Radeka, V. & Takacs, P.
System: The UNT Digital Library
Effect of High Temperature Aging on the Corrosion Resistance of Iron Based Amorphous Alloys (open access)

Effect of High Temperature Aging on the Corrosion Resistance of Iron Based Amorphous Alloys

None
Date: June 7, 2007
Creator: Day, S D; Haslam, J J; Farmer, J C & Rebak, R B
System: The UNT Digital Library
Interlayer Interaction and Electronic Screening in MultilayerGraphene (open access)

Interlayer Interaction and Electronic Screening in MultilayerGraphene

The unusual transport properties of graphene are the direct consequence of a peculiar bandstructure near the Dirac point. We determine the shape of the {pi} bands and their characteristic splitting, and find the transition from two-dimensional to bulk character for 1 to 4 layers of graphene by angle-resolved photoemission. By detailed measurements of the {pi} bands we derive the stacking order, layer-dependent electron potential, screening length and strength of interlayer interaction by comparison with tight binding calculations, yielding a comprehensive description of multilayer graphene's electronic structure.
Date: June 7, 2007
Creator: Ohta, Taisuke; Bostwick, Aaron; McChesney, J.L.; Seyller, Thomas; Horn, Karsten & Rotenberg, Eli
System: The UNT Digital Library
Classification of non-coding RNA using graph representations ofsecondary structure (open access)

Classification of non-coding RNA using graph representations ofsecondary structure

Some genes produce transcripts that function directly in regulatory, catalytic, or structural roles in the cell. These non-coding RNAs are prevalent in all living organisms, and methods that aid the understanding of their functional roles are essential. RNA secondary structure, the pattern of base-pairing, contains the critical information for determining the three dimensional structure and function of the molecule. In this work we examine whether the basic geometric and topological properties of secondary structure are sufficient to distinguish between RNA families in a learning framework. First, we develop a labeled dual graph representation of RNA secondary structure by adding biologically meaningful labels to the dual graphs proposed by Gan et al [1]. Next, we define a similarity measure directly on the labeled dual graphs using the recently developed marginalized kernels [2]. Using this similarity measure, we were able to train Support Vector Machine classifiers to distinguish RNAs of known families from random RNAs with similar statistics. For 22 of the 25 families tested, the classifier achieved better than 70% accuracy, with much higher accuracy rates for some families. Training a set of classifiers to automatically assign family labels to RNAs using a one vs. all multi-class scheme also yielded encouraging …
Date: June 7, 2004
Creator: Karklin, Yan; Meraz, Richard F. & Holbrook, Stephen R.
System: The UNT Digital Library
How Can We Test Seesaw Experimentally? (open access)

How Can We Test Seesaw Experimentally?

The seesaw mechanism for the small neutrino mass has been a popular paradigm, yet it has been believed that there is no way to test it experimentally. We present a conceivable outcome from future experiments that would convince us of the seesaw mechanism. It would involve a variety of data from LHC, ILC, cosmology, underground, and low-energy flavor violation experiments to establish the case.
Date: June 7, 2006
Creator: Buckley, Matthew R. & Murayama, Hitoshi
System: The UNT Digital Library
Cooperative sentry vehicles and differential GPS leapfrog (open access)

Cooperative sentry vehicles and differential GPS leapfrog

As part of a project for the Defense Advanced Research Projects Agency, Sandia National Laboratories Intelligent Systems and Robotics Center is developing and testing the feasibility of using a cooperative team of robotic sentry vehicles to guard a perimeter, perform a surround task, and travel extended distances. This paper describes the authors most recent activities. In particular, this paper highlights the development of a Differential Global Positioning System (DGPS) leapfrog capability that allows two or more vehicles to alternate sending DGPS corrections. Using this leapfrog technique, this paper shows that a group of autonomous vehicles can travel 22.68 kilometers with a root mean square positioning error of only 5 meters.
Date: June 7, 2000
Creator: Feddema, John T.; Lewis, Christopher L. & LaFarge, Robert A.
System: The UNT Digital Library
Silica control and materials tests at the Salton Sea geothermal field (open access)

Silica control and materials tests at the Salton Sea geothermal field

The Lawrence Livermore Laboratory maintains and operates a test facility near Niland, California, in the Imperial Valley for field studies on SSGF brine chemistry, scale and solids control, materials, and injection. Recent work in silica control and materials testing is reviewed.
Date: June 7, 1979
Creator: Quong, R.; Harrar, J. E.; McCright, R. D.; Locke, R. D.; Lorensen, L. E. & Tardiff, G. E.
System: The UNT Digital Library
Differencing asymptotic diffusion theory (open access)

Differencing asymptotic diffusion theory

A diffusion theory is presented which extends asymptotic diffusion to non-uniform material properties. Finite difference methods for the diffusion theory naturally result in jump conditions on interfaces when appropriate.
Date: June 7, 1979
Creator: Zimmerman, G.B.
System: The UNT Digital Library
Inversion approach for thermal data from a convecting hydrothermal system. Revision 1 (open access)

Inversion approach for thermal data from a convecting hydrothermal system. Revision 1

Hydrothermal systems are often studied by collecting thermal gradient data and temperature-depth curves. These data contain important information about the flow field, the evolution of the hydrothermal system, and the location and nature of the ultimate heat sources. Thermal data are conventionally interpreted by the ''forward'' method; the thermal field is calculated based on selected initial conditions and boundary conditions such as temperature and permeability distributions. If the calculated thermal field matches the data, the chosen conditions are inferred to be possibly correct. Because many sets of initial conditions may produce similar thermal fields, users of the ''forward'' method may inadvertently miss the correct set of initial conditions. Analytical methods for ''inverting'' data allow the determination of all the possible solutions consistent with the definition of the problem. In this paper the authors suggest an approach for inverting thermal data from a hydrothermal system, and compare it to the more conventional approach. The authors illustrate the difference in the methods by comparing their application to the Salton Sea Geothermal Field by Lau (1980a) and Kasameyer, et al. (1984). In this particular example, the inverse method was used to draw conclusions about the age and total rate of fluid flow into …
Date: June 7, 1985
Creator: Kasameyer, P.; Younker, L. & Hanson, J.
System: The UNT Digital Library
Particle physics and superstrings (open access)

Particle physics and superstrings

Implications of recent precision measurements of the standard model gauge coupling constants are discussed in the context of superstring theory. 40 refs.
Date: June 7, 1991
Creator: Gaillard, M.K. (California Univ., Berkeley, CA (United States). Dept. of Physics Lawrence Berkeley Lab., CA (United States))
System: The UNT Digital Library
Pulse-power circuit diagnostics for the Nova laser (open access)

Pulse-power circuit diagnostics for the Nova laser

The Nova laser will have a large pulse power system for driving laser amplifiers, incorporating approximately 1600 flashlamp circuits. An automated system has been designed for diagnosing the condition of these flashlamp circuits. It records digitized circuit current waveforms and detects current excursions above a given threshold. In addition, it is able to fire flashlamps at a low energy to ascertain the health of the system. Data from this system can be ploted for inspection by the operator, analyzed by the computer system and archived for future reference.
Date: June 7, 1982
Creator: Christie, D. J.; Dallum, G. E.; Gritton, D. G.; Merritt, B. T.; Whitham, K. & Berkbigler, L. W.
System: The UNT Digital Library
The use of the Fermilab antiproton Accumulator in medium energy physics experiments (open access)

The use of the Fermilab antiproton Accumulator in medium energy physics experiments

The Fermilab antiprotron Accumulator has been modified for use in a medium energy experiment. The experiment is conducted with circulating antiproton beam of momentum between 6.7 GeV/c and 3.7 GeV/c colliding with protons from an internal gas jet. Antiprotons are accumulated at the normal momentum of 8.9 GeV/c and then decelerated to the appropriate energy. It is necessary to cool the beam continually during the time it is colliding with the gas jet. The experiment requires new provisions for the control of magnet power supplies and low level rf system and modifications of the cooling system and high level energy systems to permit variable energy operation. Transition must be crossed to decelerate the beam below 5 GeV/c; because the deceleration is very slow, transition can not be crossed in a conventional manner. This paper will describe the required changes to the Accumulator and operating experience with protons. 8 refs., 2 figs., 1 tab.
Date: June 7, 1988
Creator: Bharadwaj, V.; Church, M.; Harms, E.; Hsueh, S.Y.; Kells, W.; MacLachlan, J. et al.
System: The UNT Digital Library
Isentropic Compression of LX-04 on the Z Accelerator (open access)

Isentropic Compression of LX-04 on the Z Accelerator

Three sets of LX-04 samples of 0.18 and 0.49 mm nominal thicknesses were all dynamically loaded by Sandia's Z-accelerator with a ramp compression wave with a 200 ns rise time and about 150 kb peak stress. The LX-04/lithium fluoride samples interface velocities were measured using VISAR's. Comparisons of experimental and computational results are given. Compression and release isentropes both show some reaction and kinetic behavior of the LX-04. Experiments were also performed on fine-grained TATB. Future experiments on single crystals of HMX that are designed to measure the phase transition at high pressures is discussed.
Date: June 7, 2001
Creator: Reisman, D B; Forbes, J W; Tarver, C M; Garcia, F; Cauble, R C; Hall, C A et al.
System: The UNT Digital Library
Gluons and the Quark Sea at High Energies: Distributions, Polarization, Tomography (open access)

Gluons and the Quark Sea at High Energies: Distributions, Polarization, Tomography

This report on the science case for an Electron-Ion Collider (EIC) is the result of a ten-week program at the Institute for Nuclear Theory (INT) in Seattle (from September 13-November 19, 2010), motivated by the need to develop a strong case for the continued study of the QCD description of hadron structure in the coming decades. Hadron structure in the valence quark region will be studied extensively with the Jefferson Lab 12 GeV science program, the subject of an INT program the previous year. The focus of the INT program was on understanding the role of gluons and sea quarks, the important dynamical degrees of freedom describing hadron structure at high energies. Experimentally, the most direct and precise way to access the dynamical structure of hadrons and nuclei at high energies is with a high luminosity lepton probe in collider mode. An EIC with optimized detectors offers enormous potential as the next generation accelerator to address many of the most important, open questions about the fundamental structure of matter. The goal of the INT program, as captured in the writeups in this report, was to articulate these questions and to identify golden experiments that have the greatest potential to provide …
Date: June 7, 2012
Creator: Boer, Daniel; Diehl, Markus; Milner, Richard; Venugopalan, Raju; Vogelsang, Werner; Kaplan, David et al.
System: The UNT Digital Library
Robust Optical Richness Estimation with Reduced Scatter (open access)

Robust Optical Richness Estimation with Reduced Scatter

Reducing the scatter between cluster mass and optical richness is a key goal for cluster cosmology from photometric catalogs. We consider various modifications to the red-sequence matched filter richness estimator of Rozo et al. (2009b), and evaluate their impact on the scatter in X-ray luminosity at fixed richness. Most significantly, we find that deeper luminosity cuts can reduce the recovered scatter, finding that {sigma}{sub ln L{sub X}|{lambda}} = 0.63 {+-} 0.02 for clusters with M{sub 500c} {approx}> 1.6 x 10{sup 14} h{sub 70}{sup -1} M{sub {circle_dot}}. The corresponding scatter in mass at fixed richness is {sigma}{sub ln M|{lambda}} {approx} 0.2-0.3 depending on the richness, comparable to that for total X-ray luminosity. We find that including blue galaxies in the richness estimate increases the scatter, as does weighting galaxies by their optical luminosity. We further demonstrate that our richness estimator is very robust. Specifically, the filter employed when estimating richness can be calibrated directly from the data, without requiring a-priori calibrations of the red-sequence. We also demonstrate that the recovered richness is robust to up to 50% uncertainties in the galaxy background, as well as to the choice of photometric filter employed, so long as the filters span the 4000 {angstrom} …
Date: June 7, 2012
Creator: Rykoff, E. S.; Koester, B. P.; Rozo, E.; Annis, J.; Evrard, A. E.; Hansen, S. M. et al.
System: The UNT Digital Library
Baryonic B Decays (open access)

Baryonic B Decays

None
Date: June 7, 2013
Creator: Shiu, Jing-Ge & /Taiwan, Natl. Taiwan U.
System: The UNT Digital Library
The BigBoss Experiment (open access)

The BigBoss Experiment

BigBOSS is a Stage IV ground-based dark energy experiment to study baryon acoustic oscillations (BAO) and the growth of structure with a wide-area galaxy and quasar redshift survey over 14,000 square degrees. It has been conditionally accepted by NOAO in response to a call for major new instrumentation and a high-impact science program for the 4-m Mayall telescope at Kitt Peak. The BigBOSS instrument is a robotically-actuated, fiber-fed spectrograph capable of taking 5000 simultaneous spectra over a wavelength range from 340 nm to 1060 nm, with a resolution R = {lambda}/{Delta}{lambda} = 3000-4800. Using data from imaging surveys that are already underway, spectroscopic targets are selected that trace the underlying dark matter distribution. In particular, targets include luminous red galaxies (LRGs) up to z = 1.0, extending the BOSS LRG survey in both redshift and survey area. To probe the universe out to even higher redshift, BigBOSS will target bright [OII] emission line galaxies (ELGs) up to z = 1.7. In total, 20 million galaxy redshifts are obtained to measure the BAO feature, trace the matter power spectrum at smaller scales, and detect redshift space distortions. BigBOSS will provide additional constraints on early dark energy and on the curvature of …
Date: June 7, 2012
Creator: Schelgel, D.; Abdalla, F.; Abraham, T.; Ahn, C.; Allende Prieto, C.; Annis, J. et al.
System: The UNT Digital Library
Probing Ferroelectricity in PbZr0.2Ti0.8O3 with Polarized Soft X-rays (open access)

Probing Ferroelectricity in PbZr0.2Ti0.8O3 with Polarized Soft X-rays

The reduction in symmetry associated with the onset of ferroelectric order in PbZr{sub 0.2}Ti{sub 0.8}O{sub 3} (PZT) thin films leads to a pronounced difference at the Ti L{sub 3,2} absorption edges between spectra measured with the x-ray linear polarization perpendicular and parallel to the ferroelectric polarization. We introduce a general method to analyze the observed difference spectra using atomic multiplet calculations. Moreover, we find experimental evidence for structural changes in PZT induced by the reversal of the ferroelectric polarization.
Date: June 7, 2010
Creator: Arenholz, E.; van der Laan, G.; Fraile-Rodriguez, A.; Yu, P.; He, Q. & Ramesh, R.
System: The UNT Digital Library
Collective behavior in recent laser-plasma experiments (open access)

Collective behavior in recent laser-plasma experiments

The absorption of 1.06 ..mu.. light focused on small C/sub 8/H/sub 8/ discs has been measured in the intensity range of 10/sup 15/ - 10/sup 17/ W/cm. The data confirms the importance of collective plasma effects in determining the absorption of intense light. The measured absorption efficiencies are in the range of 30 to 40 percent, and the scattered light has a polarization dependence. The measured absorptions are shown to be inconsistent with classical inverse bremsstrahlung. Both the magnitude of the absorption and the observed polarization dependence of the scattered light are shown to be consistent with recent calculations of light absorption via collective processes. Comparisons are made, and improved models of the light absorption are discussed with reference to the data. In addition, the heated electron energies deduced from the x-ray data are consistent with those expected via collective processes.
Date: June 7, 1976
Creator: Kruer, W. L.; Haas, R. A.; Mead, W. C.; Phillion, D. W. & Rupert, V. C.
System: The UNT Digital Library
Broad Line Radio Galaxies Observed with Fermi-LAT: The Origin of the GeV Gamma-Ray Emission (open access)

Broad Line Radio Galaxies Observed with Fermi-LAT: The Origin of the GeV Gamma-Ray Emission

We report on a detailed investigation of the {gamma}-ray emission from 18 broad line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope (LAT) data. We confirm the previously reported detections of 3C 120 and 3C 111 in the GeV photon energy range; a detailed look at the temporal characteristics of the observed {gamma}-ray emission reveals in addition possible flux variability in both sources. No statistically significant {gamma}-ray detection of the other BLRGs was however found in the considered dataset. Though the sample size studied is small, what appears to differentiate 3C 111 and 3C 120 from the BLRGs not yet detected in {gamma}-rays is the particularly strong nuclear radio flux. This finding, together with the indications of the {gamma}-ray flux variability and a number of other arguments presented, indicate that the GeV emission of BLRGs is most likely dominated by the beamed radiation of relativistic jets observed at intermediate viewing angles. In this paper we also analyzed a comparison sample of high accretion-rate Seyfert 1 galaxies, which can be considered radio-quiet counterparts of BLRGs, and found none were detected in {gamma}-rays. A simple phenomenological hybrid model applied for the broad-band emission of the discussed radio-loud and …
Date: June 7, 2012
Creator: Kataoka, J.; Stawarz, L.; Takahashi, Y.; Cheung, C. C.; Hayashida, M.; Grandi, P. et al.
System: The UNT Digital Library
A Survey of Pressure Vessel Code Compliance for Super conducting RF Cryomodules (open access)

A Survey of Pressure Vessel Code Compliance for Super conducting RF Cryomodules

Superconducting radio frequency (SRF) cavities made from niobium and cooled with liquid helium are becoming key components of many particle accelerators. The helium vessels surrounding the RF cavities, portions of the niobium cavities themselves, and also possibly the vacuum vessels containing these assemblies, generally fall under the scope of local and national pressure vessel codes. In the U.S., Department of Energy rules require national laboratories to follow national consensus pressure vessel standards or to show ''a level of safety greater than or equal to'' that of the applicable standard. Thus, while used for its superconducting properties, niobium ends up being treated as a low-temperature pressure vessel material. Niobium material is not a code listed material and therefore requires the designer to understand the mechanical properties for material used in each pressure vessel fabrication; compliance with pressure vessel codes therefore becomes a problem. This report summarizes the approaches that various institutions have taken in order to bring superconducting RF cryomodules into compliance with pressure vessel codes. In Japan, Germany, and the U.S., institutions building superconducting RF cavities integrated in helium vessels or procuring them from vendors have had to deal with pressure vessel requirements being applied to SRF vessels, including the …
Date: June 7, 2011
Creator: Peterson, Thomas; Klebaner, Arkadiy; Nicol, Tom; Theilacker, Jay; Hayano, Hitoshi; Kako, Eiji et al.
System: The UNT Digital Library