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3D HYDRA Simulations of NIF Targets (open access)

3D HYDRA Simulations of NIF Targets

The performance of NIF target designs is simulated in three dimensions using the HYDRA multiphysics radiation hydrodynamics code. In simulations of a cylindrical NIF hohlraum that include an imploding capsule, the motion of the wall material inside the hohlraum shows a high degree of axisymmetry. Laser radiation is able to propagate through the entrance hole for the required duration of the pulse. Gross hohlraum energetics in the simulation mirror the results from an axisymmetric simulation. A simulation of a copper-doped beryllium ablator NIF capsule carried out over large solid angle resolved the full spectrum of the most dangerous modes that grow from surface roughness. Hydrodynamic instabilities evolve into the weakly nonlinear regime. There is no evidence of low mode jetting driven by nonlinear mode coupling.
Date: October 20, 2000
Creator: Marinak, M. M.; Kerbel, G. D.; Gentile, N. A.; Jones, O.; Pollaine, S.; Dittrich, T. R. et al.
System: The UNT Digital Library
Abstraction of Thermal Hydrology and Coupled Processes for TSPA (open access)

Abstraction of Thermal Hydrology and Coupled Processes for TSPA

The thermal-hydrologic (TH) and coupled process models describe the evolution of a potential geologic repository as heat is released from emplaced waste. The evolution (thermal, hydrologic, chemical, and mechanical) of the engineered barrier and geologic systems is heavily dependent on the heat released by the waste packages and how the heat is transferred from the emplaced wastes through the drifts and through the repository host rock. The essential elements of this process are extracted (or abstracted) from the process-level models that incorporate the basic energy and mass conservation principles and applied to the total system models used to describe the overall performance of the potential repository. The process of total system performance assessment (TSPA) abstraction is the following. First is a description of the parameter inputs used in the process-level models. A brief description is given hereof past inputs for the viability assessment (e.g., for TSPA-VA) and current inputs for the site recommendation (TSPA-SR). This is followed by a highlight of the process-level models from which the abstractions are made. These include descriptions of TH, thermal-hydrologic-chemical (THC), and thermal-mechanical (TM) processes used to describe the performance of individual waste packages and waste emplacement drifts as well as the repository as …
Date: October 20, 2000
Creator: ITAMURA,MICHAEL T. & FRANCIS JR.,NICHOLAS D.
System: The UNT Digital Library
Accelerator mass spectrometry in biomedical research (open access)

Accelerator mass spectrometry in biomedical research

Biological effects occur in natural systems at chemical concentrations of parts per billion (1:10{sup 9}) or less. Affected biomolecules may be separable in only milligram or microgram quantities. Quantification at attomole sensitivity is needed to study these interactions. AMS measures isotope concentrations to parts per 10{sup 13--15} on milligram-sized samples and is ideal for quantifying long-lived radioisotopic labels that are commonly used to trace biochemical pathways in natural systems. {sup 14}C-AMS has now been coupled to a variety of organic separation and definition technologies. The primary research investigates pharmacokinetics and genotoxicities of toxins and drugs at very low doses. Human subject research using AMS includes nutrition, toxicity and elemental balance studies. {sup 3} H, {sup 41}Ca and {sup 26}Al are also traced by AMS for fundamental biochemical kinetic research. Expansion of biomedical AMS awaits further development of biochemical and accelerator technologies designed specifically for these applications.
Date: October 20, 1993
Creator: Vogel, J. S. & Turteltaub, K. W.
System: The UNT Digital Library
Adaptive low mach number simulations of a premixed turbulent laboratory burner (open access)

Adaptive low mach number simulations of a premixed turbulent laboratory burner

A parallel adaptive low Mach number model is used to study an experimental lean premixed turbulent methane V-flame that is stabilized on a rod spanning the exit plane of a circular nozzle. The fuel is turbulent due to an upstream perforated-plate, and the resulting flame extends downstream of the rod. We present three-dimensional time-dependent simulations of this configuration. The computations incorporate detailed reaction chemistry and transport using a dynamically adaptive block-structured grid algorithm and a time-split integration procedure. Flow field and flame surface statistics are gathered from the experiment and are compared to the computed results.
Date: October 20, 2003
Creator: Day, M.S.; Bell, J.B.; Lijewski, M.J.; Johnson, M.; Cheng, R.K. & Shepherd, I.G.
System: The UNT Digital Library
ANALYSIS OF THE LEACHING EFFICIENCY OF INHIBITED WATER AND TANK SIMULANT IN REMOVING RESIDUES ON THERMOWELL PIPES (open access)

ANALYSIS OF THE LEACHING EFFICIENCY OF INHIBITED WATER AND TANK SIMULANT IN REMOVING RESIDUES ON THERMOWELL PIPES

A key component for the accelerated implementation and operation of the Salt Waste Processing Facility (SWPF) is the recovery of Tank 48H. Tank 48H is a type IIIA tank with a maximum capacity of 1.3 million gallons. Video inspection of the tank showed that a film of solid material adhered to the tank internal walls and structures between 69 inch and 150 inch levels. From the video inspection, the solid film thickness was estimated to be 1mm, which corresponds to {approx}33 kg of TPB salts (as 20 wt% insoluble solids) (1). This film material is expected to be easily removed by single-rinse, slurry pump operation during Tank 48H TPB disposition via aggregation processing. A similar success was achieved for Tank 49H TPB dispositioning, with slurry pumps operating almost continuously for approximately 6 months, after which time the tank was inspected and the film was found to be removed. The major components of the Tank 49H film were soluble solids - Na{sub 3}H(CO{sub 3}){sub 2} (Hydrated Sodium Carbonate, aka: Trona), Al(OH){sub 3} (Aluminum Hydroxide, aka: Gibbsite), NaTPB (Sodium Tetraphenylborate), NaNO{sub 3} (Sodium Nitrate) and NaNO{sub 2} (Sodium Nitrite) (2). Although the Tank 48H film is expected to be primarily soluble solids, …
Date: October 20, 2011
Creator: Fondeur, F.; White, T.; Oji, L.; Martino, C. & Wilmarth, B.
System: The UNT Digital Library
Angular biasing in implicit Monte-Carlo (open access)

Angular biasing in implicit Monte-Carlo

Calculations of indirect drive Inertial Confinement Fusion target experiments require an integrated approach in which laser irradiation and radiation transport in the hohlraum are solved simultaneously with the symmetry, implosion and burn of the fuel capsule. The Implicit Monte Carlo method has proved to be a valuable tool for the two dimensional radiation transport within the hohlraum, but the impact of statistical noise on the symmetric implosion of the small fuel capsule is difficult to overcome. We present an angular biasing technique in which an increased number of low weight photons are directed at the imploding capsule. For typical parameters this reduces the required computer time for an integrated calculation by a factor of 10. An additional factor of 5 can also be achieved by directing even smaller weight photons at the polar regions of the capsule where small mass zones are most sensitive to statistical noise.
Date: October 20, 1994
Creator: Zimmerman, G.B.
System: The UNT Digital Library
Certification testing for small wind turbines (open access)

Certification testing for small wind turbines

This paper describes the testing procedures for obtaining type certification for a small wind turbine. Southwest Windpower (SWWP) is seeking type certification from Underwriters Laboratory (UL) for the AIR 403 wind turbine. UL is the certification body and the National Renewable Energy Laboratory (NREL) is providing technical assistance including conducting the certification testing. This is the first small turbine to be certified in the US, therefore standards must be interpreted and test procedures developed.
Date: October 20, 1999
Creator: Corbus, D.; Link, H.; Butterfield, S.; Stork, C. & Newcomb, C.
System: The UNT Digital Library
Cham and Charmoniium Spectroscopy (open access)

Cham and Charmoniium Spectroscopy

The last few years have seen a revival of interest in charm spectroscopy with more than a dozen new states being reported and hundreds of new theoretical investigations being published. The advent of the B-factories [1,2], with their large, charm-rich data samples, has proven crucial to the discovery and investigation of new charm hadron states, but other experiments have confirmed and complemented the B-factory observations. Much interest has been generated by several new states that do not appear to be easily incorporated in the conventional picture of charm and charmonium mesons. Here, the focus is on the latest experimental results in charm spectroscopy and the determination of the nature of the recently discovered states. Recent experimental results in charm and charmonium spectroscopy are reviewed.
Date: October 20, 2006
Creator: Petersen, Brian Aa.
System: The UNT Digital Library
THE CHEMICAL AND RADIATION RESISTANCE OF POLYPHENYLENE SULFIDE AS ENCOUNTERED IN THE NUCLEAR WASTE CLEANING PROCESSES (open access)

THE CHEMICAL AND RADIATION RESISTANCE OF POLYPHENYLENE SULFIDE AS ENCOUNTERED IN THE NUCLEAR WASTE CLEANING PROCESSES

Polyphenylene sulfide (PPS) is extremely resistant to gamma irradiation, caustic solution, and dilute nitric acid. PPS is the material of construction for the coalescers used in the Modular Caustic-Side Solvent Extraction Unit (MCU). After applying the equivalent of 16 years of gamma irradiation and several months of exposures to caustic solution, no dimensional changes nor chemical changes were detected in PPS whether the PPS was in fiber form or in a composite with E-glass fibers. However, PPS acts as a media for heterogeneous nucleation. In particular, PPS appears to favor aluminosilicate formation in saturated solutions of aluminum and silicon in caustic environments. Parallel testing, in progress, is examining the stability of PPS when exposed to the new solvent formulation under development for MCU. Preliminary data, after two months of exposure, PPS is remarkably stable to the new solvent.
Date: October 20, 2011
Creator: Fondeur, F.
System: The UNT Digital Library
The Circular Rfq Storage Ring (open access)

The Circular Rfq Storage Ring

This paper presents a novel idea of storage ring for the accumulation of intense beams of light and heavy ions at low energy. The new concept is a natural development of the combined features used in a conventional storage ring and an ion trap, and is basically a linear RFQ bend on itself. In summary the advantages are: smaller beam dimensions, higher beam intensity, and a more compact storage device.
Date: October 20, 1998
Creator: Ruggiero, A. G.
System: The UNT Digital Library
Coherent control of atomic excitation using off-resonant strong few-cycle pulses (open access)

Coherent control of atomic excitation using off-resonant strong few-cycle pulses

Article on coherent control of atomic excitation using off-resonant strong few-cycle pulses.
Date: October 20, 2010
Creator: Jha, Pankaj K.; Eleuch, Hichem & Rostovtsev, Yuri V.
System: The UNT Digital Library
Coldmass for Lhc Dipole Insertion Magnets. (open access)

Coldmass for Lhc Dipole Insertion Magnets.

Brookhaven National Laboratory (BNL) is building a number of magnets for the insertion regions of the Large Hadron Collider (LHC). This paper presents the magnetic design and the expected field quality in 2-in-1 dipole magnets. A unique feature of this coldmass design is the use of an oblate-shaped yoke. This concept permits a variety of BNL-built magnets to have a similar overall design and allows the LHC main dipole cryostat, post, etc., to be used in these magnets. The proposed oblate-shaped yoke also offers a way to reduce the overall cryostat size in future magnets. The dipoles will use the same 80 mm aperture coils as used in the Relativistic Heavy Ion Collider (RHIC) dipole magnets, but will use stainless steel collars. The design presented here is still evolving and the magnets may be built differently than described here.
Date: October 20, 1997
Creator: Gupta, R.; Alforque, R.; Anerella, M.; Kelly, E.; Plate, S.; Rufer, C. et al.
System: The UNT Digital Library
A Combined Scintimammography/Stereotactic Core Biopsy Digital X-ray System (open access)

A Combined Scintimammography/Stereotactic Core Biopsy Digital X-ray System

Jefferson Lab, Hampton University and the Riverside Regional Medical Center are collaborating in a clinical study employing a dual modality imaging system utilizing scintimammography and digital radiography. The purpose of the study is to obtain clinical data on the reliability of scintimammography in predicting the malignancy of suspected breast lesions with the ultimate goal to reduce the number of false positives associated with conventional x-ray mammography. The scintimammography gamma camera is a custom built mini gamma camera with an active area of 5.3 cm x 5.3 cm based on a 2x2 array of Hamamatsu R7600-C8 position sensitive photomultiplier tubes. The spatial resolution of the gamma camera at the collimator surface is <4 mm FWHM and the sensitivity is 4000 cps/mCi. Preliminary results are that of the six cases that indicated a lesion with high uptake of MiraLuma ({sup 99m}Tc-sestamibi) five were positive for cancer. Out of a total of 25 patients in the study, all cases negative for MiraLuma uptake were confirmed negative via the biopsy pathology. The scintimammography results indicate that the lesions become visible with the mini gamma camera within 3 minutes post injection of MiraLuma.
Date: October 20, 2000
Creator: Weisenberger, A. G.; Barbosa, F.; Green, T. D.; Hoefer, R.; Keppel, C.; Kross, B. et al.
System: The UNT Digital Library
Compostable, fully biobased foams using PLA and micro cellulose for zero energy buildings (open access)

Compostable, fully biobased foams using PLA and micro cellulose for zero energy buildings

Article examining foams made from polylactic acid (PLA) and micro cellulose fibrils (MCF) to address the need for bio-resourced foams for the building industry.
Date: October 20, 2020
Creator: Oluwabunmi, Kayode; D'Souza, Nandika Anne, 1967-; Zhao, Weihuan; Choi, Tae-Youl & Theyson, Thomas
System: The UNT Digital Library
Cone Penetrometer Off-Surface Sensor (open access)

Cone Penetrometer Off-Surface Sensor

Cone penetrometer technology accounts for approximately 50 percent of the subsurface drilling done at the Savannah River Site. This technology provides a means of collecting data for use in the characterization of the subsurface. The cone penetrometer consists of a steel cone attached to a pipe column that is hydraulically inserted into the ground. To allow researchers to accurately measure subsurface properties, without the inherent problems of cone penetrometer equipment, the Savannah River Technology Center has developed the Cone Penetrometer Off-Surface Sensor (CPOSS). The CPOSS design consists of a knife-blade mechanism mounted along the surface of a module capable of attaching to existing cone penetrometer equipment and being deployed at depths of up to 200 feet. CPOSS development is the subject of this report.
Date: October 20, 1999
Creator: Smail, T. R.; French, P. J.; Huffman, R. K. & Hebert, P. S.
System: The UNT Digital Library
Corrosion Resistances of Iron-Based Amorphous Metals with Yttrium and Tungsten Additions in Hot Calcium Chloride Brine & Natural Seawater: Fe48Mo14Cr15Y2C15B6 and W-Containing Variants (open access)

Corrosion Resistances of Iron-Based Amorphous Metals with Yttrium and Tungsten Additions in Hot Calcium Chloride Brine & Natural Seawater: Fe48Mo14Cr15Y2C15B6 and W-Containing Variants

Yttrium-containing SAM1651 (Fe{sub 48.0}Cr{sub 15.0}Mo{sub 14.0}B{sub 6.0}C{sub 15.0}Y{sub 2.0}), has a critical cooling rate (CCR) of approximately 80 Kelvin per second, while SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) with no yttrium has a higher critical cooling rate of approximately 600 Kelvin per second. SAM1651's low CCR enables it to be rendered as a completely amorphous material in practical materials processes. Chromium (Cr), molybdenum (Mo) and tungsten (W) provide corrosion resistance; boron (B) enables glass formation; and rare earths such as yttrium (Y) lower critical cooling rate (CCR). The passive film stability of these Fe-based amorphous metal formulations have been found to be superior to that of conventional stainless steels, and comparable to that of Ni-based alloys, based on electrochemical measurements of the passive film breakdown potential and general corrosion rates.
Date: October 20, 2006
Creator: Farmer, J C; Haslam, J; Day, S; Lian, T; Saw, C; Hailey, P et al.
System: The UNT Digital Library
Coupled Thermal-Hydrological-Mechanical Analyses of the Yucca Mountain Drift Scale Test - Comparison of Field Measurements to Predictions of Four Different Numerical Models (open access)

Coupled Thermal-Hydrological-Mechanical Analyses of the Yucca Mountain Drift Scale Test - Comparison of Field Measurements to Predictions of Four Different Numerical Models

None
Date: October 20, 2004
Creator: Rutqvist, J.; Barr, D.; Datta, R.; Gens, A.; Millard, A.; Olivella, S. et al.
System: The UNT Digital Library
Current Issues in Terrestrial Solar Radiation Instrumentation for Energy, Climate and Space Applications Preprint prepared for New RAD '99 (open access)

Current Issues in Terrestrial Solar Radiation Instrumentation for Energy, Climate and Space Applications Preprint prepared for New RAD '99

Reductions of uncertainty in terrestrial solar radiation measurements are needed to validate the Earth's radiation balance derived from satellite data. Characterization of solar energy resources for renewable technologies requires greater time and spatial resolution for economical technology deployment. Solar radiation measurement research at the National Renewable Energy Laboratory addresses calibrations, operational characteristics, and corrections for terrestrial solar radiation measurements. We describe progress in measurements of broadband diffuse-sky radiation, and characterization of field instrument thermal offsets and spectral irradiance. The need and prospects for absolute references for diffuse and long-wave terrestrial solar radiation measurements are discussed. Reductions in uncertainty of broadband irradiance measurements from tens of watts per square meter to a few (one to two) watts per square meter are reported, which reduce time and labor to quantify and identify trends in artificial optical radiation sources, terrestrial solar radiation, and the Earth's radiation budget.
Date: October 20, 1999
Creator: Stoffel, T. L.; Reda, I.; Myers, D. R.; Renne, D.; Wilcox, S. W. & Treadwell, J.
System: The UNT Digital Library
Cycles in fossil diversity (open access)

Cycles in fossil diversity

It is well-known that the diversity of life appears to fluctuate during the course the Phanerozoic, the eon during which hard shells and skeletons left abundant fossils (0-542 Ma). Using Sepkoski's compendium of the first and last stratigraphic appearances of 36380 marine genera, we report a strong 62 {+-} 3 Myr cycle, which is particularly strong in the shorter-lived genera. The five great extinctions enumerated by Raup and Sepkoski may be an aspect of this cycle. Because of the high statistical significance, we also consider contributing environmental factors and possible causes.
Date: October 20, 2004
Creator: Rohde, Robert A. & Muller, Richard A.
System: The UNT Digital Library
Defect reduction in (112_O) a-plane GaN by two-stage epitaxiallateral overgrowth (open access)

Defect reduction in (112_O) a-plane GaN by two-stage epitaxiallateral overgrowth

In the epitaxial lateral overgrowth (ELO) of (11{bar 2}0) a-plane GaN, the uneven growth rates of two opposing wings, Ga- and N-wings, makes the coalescence of two neighboring wings more difficult than that in c-plane GaN. We report a two-stage growth method to get uniformly coalesced epitaxial lateral overgrown a-plane GaN using metalorganic chemical vapor deposition (MOCVD) by employing relatively lower growth temperature in the first step followed by enhanced lateral growth in the second. Using this method, the height differences between Ga-polar and N-polar wings at the coalescence front could be reduced, thereby making the coalescence of two wings much easier. Transmission electron microscopy (TEM) showed that the threading dislocation density in the wing areas was 1.0x10{sup 8}cm{sup -2}, more than two orders of magnitude lower than that in the window areas (4.2x10{sup 10}cm{sup -2}). However, high density of basal stacking faults of 1.2x104 cm-1 was still observed in the wing areas as compared to c-plane GaN. Atomic force microscopy and photoluminescence measurements on the coalesced ELO a-GaN sample also indicated improved material quality.
Date: October 20, 2006
Creator: Ni, X.; Ozgur, U.; Fu, Y.; Biyikli, N.; Xie, J.; Baski, A.A. et al.
System: The UNT Digital Library
Deliquescence of NaCl-NaNO3, KNO3-NaNO3, and NaCl-KNO3 Salt Mixtures From 90 to 120?C (open access)

Deliquescence of NaCl-NaNO3, KNO3-NaNO3, and NaCl-KNO3 Salt Mixtures From 90 to 120?C

We conducted reversed deliquescence experiments in saturated NaCl-NaNO{sub 3}-H{sub 2}O, KNO{sub 3}-NaNO{sub 3}-H{sub 2}O, and NaCl-KNO{sub 3}-H{sub 2}O systems from 90 to 120 C as a function of relative humidity and solution composition. NaCl, NaNO{sub 3}, and KNO{sub 3} represent members of dust salt assemblages that are likely to deliquesce and form concentrated brines on high-level radioactive waste package surfaces in a repository environment at Yucca Mountain, NV, USA. Discrepancy between model prediction and experimental code can be as high as 8% for relative humidity and 50% for dissolved ion concentration. The discrepancy is attributed primarily to the use of 25 C models for Cl-NO{sub 3} and K-NO{sub 3} ion interactions in the current Yucca Mountain Project high-temperature Pitzer model to describe the non-ideal behavior of these highly concentrated solutions.
Date: October 20, 2004
Creator: Carroll, S A; Craig, L & Wolery, T J
System: The UNT Digital Library
Design, implementation and testing of extended and mixed precisionBLAS (open access)

Design, implementation and testing of extended and mixed precisionBLAS

This article describes the design rationale, a C implementation, and conformance testing of a subset of the new Standard for the BLAS (Basic Linear Algebra Subroutines): Extended and Mixed Precision BLAS. Permitting higher internal precision and mixed input/output types and precisions allows us to implement some algorithms that are simpler, more accurate, and sometimes faster than possible without these features. The new BLAS are challenging to implement and test because there are many more subroutines than in the existing Standard, and because we must be able to assess whether a higher precision is used for internal computations than is used for either input or output variables. We have therefore developed an automated process of generating and systematically testing these routines. Our methodology is applicable to languages besides C. In particular, our algorithms used in the testing code will be valuable to all other BLAS implementors. Our extra precision routines achieve excellent performance--close to half of the machine peak Megaflop rate even for the Level 2 BLAS, when the data access is stride one.
Date: October 20, 2000
Creator: Li, X. S.; Demmel, J. W.; Bailey, D. H.; Henry, G.; Hida, Y.; Iskandar, J. et al.
System: The UNT Digital Library
Design of the commissioning filter/mask/window assembly for undulator beamline front ends at the Advanced Photon Source (open access)

Design of the commissioning filter/mask/window assembly for undulator beamline front ends at the Advanced Photon Source

A compact filter/mask/window assembly has been designed for undulator beamline commissioning activity at the Advanced Photon Source beamlines. The assembly consists of one 300-{mu}m graphite filter, one 127-{mu}m CVD diamond filter and two 250-{mu}m beryllium windows. A water-cooled Glidcop fixed mask with a 4.5-mm {times} 4.5-mm output optical aperture and a 0.96-mrad {times} 1.6-mrad beam missteering acceptance is a major part in the assembly. The CVD diamond filter which is mounted on the downstream side of the fixed mask is designed to also function as a transmitting x-ray beam position monitor. The sum signal from the latter can be used to monitor the physical condition of the graphite filter and prevent any possible chain reaction damage to the beryllium windows downstream. In this paper, the design concept as well as the detailed structural design of the commissioning window are presented. Further applications of the commissioning window commissioning window components are also discussed.
Date: October 20, 1995
Creator: Shu, D. & Kuzay, T. M.
System: The UNT Digital Library
DETECTION OF TWO MASSIVE CO SYSTEMS IN 4C 41.17 AT z=3.8 (open access)

DETECTION OF TWO MASSIVE CO SYSTEMS IN 4C 41.17 AT z=3.8

We have detected CO(4-3) in the z=3.8 radio galaxy 4C 41.17 with the IRAM Interferometer. The CO is in two massive (M{sub dyn} {approx}> 2.5 x 10{sup 11} M{sub {circle_dot}}) systems separated by 1.8 (13 kpc), and by 400 km s{sup -1} in velocity, which coincide with two different dark lanes in a deep Ly{alpha} image. One CO component coincides with the cm-radio core of the radio galaxy, and its redshift is close to that of the He II {lambda} 1640 AGN line. The second CO component is near the base of a cone-shaped region southwest of the nucleus, which resembles the emission-line cones seen in nearby AGN and starburst galaxies. The characteristics of the CO sources and their mm/submm dust continuum are similar to those found in ultraluminous IR galaxies and in some high-z radio galaxies and quasars. The fact that 4C 41.17 contains two CO systems is further evidence for the role of mergers in the evolution of galaxies at high redshift.
Date: October 20, 2004
Creator: DeBreuck, C; Downes, D; Neri, R; van Breugel, W; Reuland, M; Omont, A et al.
System: The UNT Digital Library