Resource Type

Language

Provably Optimal Parallel Transport Sweeps on Regular Grids (open access)

Provably Optimal Parallel Transport Sweeps on Regular Grids

None
Date: January 31, 2013
Creator: Adams, M. P.; Adams, M. L.; Hawkins, W. D.; Smith, T.; Rauchwerger, L.; Amato, N. M. et al.
System: The UNT Digital Library
Technical basis for dose reconstruction (open access)

Technical basis for dose reconstruction

The purpose of this paper is to consider two general topics: technical considerations of why dose-reconstruction studies should or should not be performed and methods of dose reconstruction. The first topic is of general and growing interest as the number of dose-reconstruction studies increases, and one asks the question whether it is necessary to perform a dose reconstruction for virtually every site at which, for example, the Department of Energy (DOE) has operated a nuclear-related facility. And there is the broader question of how one might logically draw the line at performing or not performing dose-reconstruction (radiological and chemical) studies for virtually every industrial complex in the entire country. The second question is also of general interest. There is no single correct way to perform a dose-reconstruction study, and it is important not to follow blindly a single method to the point that cheaper, faster, more accurate, and more transparent methods might not be developed and applied.
Date: January 31, 1996
Creator: Anspaugh, Lynn R.
System: The UNT Digital Library
The task force process (open access)

The task force process

This paper focuses on the unique aspects of the Fernald Citizens Task Force process that have contributed to a largely successful public participation effort at Fernald. The Fernald Citizens Task Force passed quickly by many procedural issues. Instead, the Task Force concentrated on (a) educating itself about the site, its problems, and possible solutions, and (b) choosing a directed way to approach its mandate: To make recommendations on several {open_quotes}big picture{close_quotes} issues, including future use of the site, cleanup levels, waste disposition, and cleanup priorities. This paper presents the approach used at Fernald for establishing and running a focused site-specific advisory board, the key issues that have been faced, and how these issues were resolved. The success of Fernald in establishing a strong and functioning site-specific advisory board serves as a useful model for other DOE facilities, although the Fernald model is just one of many approaches that can be taken. However, the approach presented here has worked extremely well for Fernald.
Date: January 31, 1995
Creator: Applegate, J. S.
System: The UNT Digital Library
Zeaxanthin Radical Cation Formation in Minor Light-Harvesting Complexes of Higher Plant Antenna (open access)

Zeaxanthin Radical Cation Formation in Minor Light-Harvesting Complexes of Higher Plant Antenna

Previous work on intact thylakoid membranes showed that transient formation of a zeaxanthin radical cation was correlated with regulation of photosynthetic light-harvesting via energy-dependent quenching. A molecular mechanism for such quenching was proposed to involve charge transfer within a chlorophyll-zeaxanthin heterodimer. Using near infrared (880-1100 nm) transient absorption spectroscopy, we demonstrate that carotenoid (mainly zeaxanthin) radical cation generation occurs solely in isolated minor light-harvesting complexes that bind zeaxanthin, consistent with the engagement of charge transfer quenching therein. We estimated that less than 0.5percent of the isolated minor complexes undergo charge transfer quenching in vitro, whereas the fraction of minor complexes estimated to be engaged in charge transfer quenching in isolated thylakoids was more than 80 times higher. We conclude that minor complexes which bind zeaxanthin are sites of charge transfer quenching in vivo and that they can assume Non-quenching and Quenching conformations, the equilibrium LHC(N)<--> LHC(Q) of which is modulated by the transthylakoid pH gradient, the PsbS protein, and protein-protein interactions.
Date: January 31, 2008
Creator: Avenson, Thomas H.; Ahn, Tae Kyu; Zigmantas, Donatas; Niyogi, Krishna K.; Li, Zhirong; Ballottari, Matteo et al.
System: The UNT Digital Library
Image processing and control of a programmable spatial light modulator (open access)

Image processing and control of a programmable spatial light modulator

None
Date: January 31, 2011
Creator: Awwal, A.; Leach, R.; Brunton, G.; Tse, E.; Matone, J. & Heebner, J.
System: The UNT Digital Library
INHIBITION OF STRESS CORROSION CRACKING OF CARBON STEEL STORAGE TANKS AT HANFORD (open access)

INHIBITION OF STRESS CORROSION CRACKING OF CARBON STEEL STORAGE TANKS AT HANFORD

The stress corrosion cracking (SCC) behavior of A537 tank steel was investigated in a series of environments designed to simulate the chemistry of legacy nuclear weapons production waste. Tests consisted of both slow strain rate tests using tensile specimens and constant load tests using compact tension specimens. Based on the tests conducted, nitrite was found to be a strong SCC inhibitor. Based on the test performed and the tank waste chemistry changes that are predicted to occur over time, the risk for SCC appears to be decreasing since the concentration of nitrate will decrease and nitrite will increase.
Date: January 31, 2007
Creator: BOOMER, K.D.
System: The UNT Digital Library
ON THE ANODIC POLARIZATION BEHAVIOR OF CARBON STEEL IN HANFORD NUCLEAR WASTES (open access)

ON THE ANODIC POLARIZATION BEHAVIOR OF CARBON STEEL IN HANFORD NUCLEAR WASTES

The effect of the important chemical constituents in the Hanford nuclear waste simulant on the anodic behavior of carbon steel was studied. Specifically, the effect of pH, nitrite concentration, nitrite/nitrate concentration ratios, total organic carbon and the chloride concentration on the open circuit potential, pitting potential and repassivation potential was evaluated. It was found that pH adjusting, although capable of returning the tank chemistry back to specification, did not significantly reduce the corrosivity of the stimulant compared to the present condition. Nitrite was found to be a potent inhibitor for carbon steel. A critical concentration of approximately 1.2M appeared to be beneficial to increase the difference of repassivation potential and open circuit potential considerably and thus prevent pitting corrosion from occurring. No further benefit was gained when increasing nitrite concentration to a higher level. The organic compounds were found to be weak inhibitors in the absence of nitrite and the change of chloride from 0.05M to 0.2M did not alter the anodic behavior dramatically.
Date: January 31, 2007
Creator: BOOMER, K.D.
System: The UNT Digital Library
Experimental Mathemataics: Examples, Methods andImplications (open access)

Experimental Mathemataics: Examples, Methods andImplications

Recent years have seen the flowering of ''experimental'' mathematics, namely the utilization of modern computer technology as an active tool in mathematical research. This development is not limited to a handful of researchers, nor to a handful of universities, nor is it limited to one particular field of mathematics. Instead, it involves hundreds of individuals, at many different institutions, who have turned to the remarkable new computational tools now available to assist in their research, whether it be in number theory, algebra, analysis, geometry or even topology. These tools are being used to work out specific examples, generate plots, perform various algebraic and calculus manipulations, test conjectures, and explore routes to formal proof. Using computer tools to test conjectures is by itself a major time saver for mathematicians, as it permits them to quickly rule out false notions.
Date: January 31, 2005
Creator: Bailey, David H. & Borwein, Jonathan M.
System: The UNT Digital Library
Multi-Resolution Modeling of Large Scale Scientific Simulation Data (open access)

Multi-Resolution Modeling of Large Scale Scientific Simulation Data

This paper discusses using the wavelets modeling technique as a mechanism for querying large-scale spatio-temporal scientific simulation data. Wavelets have been used successfully in time series analysis and in answering surprise and trend queries. Our approach however is driven by the need for compression, which is necessary for viable throughput given the size of the targeted data, along with the end user requirements from the discovery process. Our users would like to run fast queries to check the validity of the simulation algorithms used. In some cases users are welling to accept approximate results if the answer comes back within a reasonable time. In other cases they might want to identify a certain phenomena and track it over time. We face a unique problem because of the data set sizes. It may take months to generate one set of the targeted data; because of its shear size, the data cannot be stored on disk for long and thus needs to be analyzed immediately before it is sent to tape. We integrated wavelets within AQSIM, a system that we are developing to support exploration and analyses of tera-scale size data sets. We will discuss the way we utilized wavelets decomposition in …
Date: January 31, 2003
Creator: Baldwin, Chuck; Abdulla, Ghaleb & Critchlow, Terence
System: The UNT Digital Library
Geological disposal investigations in granite at the Nevada test site (open access)

Geological disposal investigations in granite at the Nevada test site

The Climax stock at NTS was the site of weapons effects tests and is to be used for radwaste disposal studies. The layout of Climax and proposed experiments is illustrated. Geology of Climax is described briefly. Thermal tests showed the thermal conductivity to be essentially isotropic, only slightly temperature-dependent, and 3.0 W/m-/sup 0/K. Permeability is less than 1 nanodarcy. Plans for a spent fuel storage test and for rock mechanics tests are described. (DLC)
Date: January 31, 1979
Creator: Ballou, L. B.
System: The UNT Digital Library
The Hadronic Models for Cosmic Ray Physics: the FLUKA Code Solutions (open access)

The Hadronic Models for Cosmic Ray Physics: the FLUKA Code Solutions

FLUKA is a general purpose Monte Carlo transport and interaction code used for fundamental physics and for a wide range of applications. These include Cosmic Ray Physics (muons, neutrinos, EAS, underground physics), both for basic research and applied studies in space and atmospheric flight dosimetry and radiation damage. A review of the hadronic models available in FLUKA and relevant for the description of cosmic ray air showers is presented in this paper. Recent updates concerning these models are discussed. The FLUKA capabilities in the simulation of the formation and propagation of EM and hadronic showers in the Earth's atmosphere are shown.
Date: January 31, 2007
Creator: Battistoni, G.; Garzelli, M.V.; Gadioli, E.; Muraro, S.; Sala, P.R.; Fasso, A. et al.
System: The UNT Digital Library
Superconducting Thallium Oxide and Mercury Oxide Film (open access)

Superconducting Thallium Oxide and Mercury Oxide Film

Previously we reported on a two-layer electrodeposition process of thallium oxide superconductors that showed transport critical current density above 106 A/cm2 at 77 K in zero field. In this article, we report our effort to convert an electrodeposited thick film of (Tl,Bi,Pb)2(Sr,Ba)2Ca1Cu2Ox to (Hg,Bi,Pb)2(Sr,Ba)2Ca1Cu2Ox by the cation-exchange process. We are also reporting magneto-optical imaging data on Tl oxide superconductor films, which are compared with YBCO. Magneto-optical imaging provides insight into the nature of current flow in the Tl oxide superconductor, and thus, will help us to improve the critical current density in bulk high-temperature superconductor wire or tape.
Date: January 31, 2001
Creator: Bhattacharya, R. N.; Blaugher, R. D.; Yan, S. L.; Xing, Z. W.; Xie, Y. Y.; Wu, J. Z. et al.
System: The UNT Digital Library
Effect of CTE on Fatigue Cracking of Stainless Steel Vessels (open access)

Effect of CTE on Fatigue Cracking of Stainless Steel Vessels

Visual examination of lithium hydride reactor vessels revealed cracks that were adjacent to welds. Most cracks were parallel to the weld in the bottom portion of the vessel. Sections were cut out of the vessel containing these cracks and examined using the metallograph, scanning electron microscope, and microprobe to determine the cause of cracking. most of the cracks originated on the outer surface just outside the weld fusion line in the heat affected zone and propagated along grain boundaries. Crack depth of those sections examined ranged from about 300 to 500 {micro}m. Other cracks were reported to have reached a maximum depth of 0.32-cm (0.125-inch). The primary cause of cracking was the creation of high tensile stresses associated with the CTE differences between the filler metal and the base metal during operation of the vessel in a thermally cyclic environment. This failure mechanism could be described as creep-type fatigue whereby crack propagation might have been aided by the presence of brittle chromium carbides along the grain boundaries, which is indicative of a slightly sensitized microstructure.
Date: January 31, 2002
Creator: Bird, E. L. & Mustaleski, T. M.
System: The UNT Digital Library
Complete sequences of the highly rearranged molluscan mitochondrial genomes of the scaphopod graptacme eborea and the bivalve mytilus edulis (open access)

Complete sequences of the highly rearranged molluscan mitochondrial genomes of the scaphopod graptacme eborea and the bivalve mytilus edulis

We have determined the complete sequence of the mitochondrial genome of the scaphopod mollusk Graptacme eborea (Conrad, 1846) (14,492 nts) and completed the sequence of the mitochondrial genome of the bivalve mollusk Mytilus edulis Linnaeus, 1758 (16,740 nts). (The name Graptacme eborea is a revision of the species formerly known as Dentalium eboreum.) G. eborea mtDNA contains the 37 genes that are typically found and has the genes divided about evenly between the two strands, but M. edulis contains an extra trnM and is missing atp8, and has all genes on the same strand. Each has a highly rearranged gene order relative to each other and to all other studied mtDNAs. G. eborea mtDNA has almost no strand skew, but the coding strand of M. edulis mtDNA is very rich in G and T. This is reflected in differential codon usage patterns and even in amino acid compositions. G. eborea mtDNA has fewer non-coding nucleotides than any other mtDNA studied to date, with the largest non-coding region being only 24 nt long. Phylogenetic analysis using 2,420 aligned amino acid positions of concatenated proteins weakly supports an association of the scaphopod with gastropods to the exclusion of Bivalvia, Cephalopoda, and Polyplacophora, …
Date: January 31, 2004
Creator: Boore, Jeffrey L.; Medina, Monica & Rosenberg, Lewis A.
System: The UNT Digital Library
Harmonic resolution as a holographic quantum number (open access)

Harmonic resolution as a holographic quantum number

The Bekenstein bound takes the holographic principle into the realm of flat space, promising new insights on the relation of non-gravitational physics to quantum gravity. This makes it important to obtain a precise formulation of the bound. Conventionally, one specifies two macroscopic quantities, mass and spatial width, which cannot be simultaneously diagonalized. Thus, the counting of compatible states is not sharply defined. The resolution of this and other formal difficulties leads naturally to a definition in terms of discretized light-cone quantization. In this form, the area difference specified in the covariant bound converts to a single quantum number, the harmonic resolution K. The Bekenstein bound then states that the Fock space sector with K units of longitudinal momentum contains no more than exp(2 pi^2 K) independent discrete states. This conjecture can be tested unambiguously for a given Lagrangian, and it appears to hold true for realistic field theories, including models arising from string compactifications. For large K, it makes contact with more conventional but less well-defined formulations.
Date: January 31, 2004
Creator: Bousso, Raphael
System: The UNT Digital Library
Quantifying the Contribution of Lubrication Oil Carbon to Particulate Emissions from a Diesel Engine (open access)

Quantifying the Contribution of Lubrication Oil Carbon to Particulate Emissions from a Diesel Engine

The contribution of lubrication oil to particulate matter (PM) emissions from a Cummins B5.9 Diesel engine was measured using accelerator mass spectrometry to trace carbon isotope concentrations. The engine operated at fixed medium load (285 N-m (210 ft.lbs.) at 1600 rpm) used 100% biodiesel fuel (8100) with a contemporary carbon-14 ({sup 14}C) concentration of 103 amol {sup 14}C mg C. The {sup 14}C concentration of the exhaust CO{sub 2} and PM were 102 and 99 amol {sup 14}C/mg C, respectively. The decrease in {sup 14}C content in the CO, and PM are due to the consumption of lubrication oil which is {sup 14}C-free. Approximately 4% of the carbon in PM came from lubrication oil under these operating conditions.
Date: January 31, 2003
Creator: Buchholz, B. A.; Dibble, R. W.; Rich, D. & Cheng, A. S.
System: The UNT Digital Library
Hard processes and perturbative QCD results from CDF (open access)

Hard processes and perturbative QCD results from CDF

We present results on the inclusive jet cross section at (square root)s = 1800 GeV and 630 GeV, the two-jet cross section, multijet physics and the multijet differential cross section from the CDF experiment at the Fermilab Tevatron Collider.
Date: January 31, 1998
Creator: Buckley-Geer, Elizabeth
System: The UNT Digital Library
Model-based processing for shallow ocean environments: The broadband problem (open access)

Model-based processing for shallow ocean environments: The broadband problem

Most acoustic sources found is the ocean environmental are spatially complex and broadband. When propagating in a shallow ocean these source characteristics complicate the analysis of received acoustic data considerably. The enhancement of broadband acoustic pressure- field measurements using a vertical array is discussed. Here a model- based approach is developed for a broadband source using a normal- mode propagation model.
Date: January 31, 1996
Creator: Candy, J. V. & Sullivan, E. J.
System: The UNT Digital Library
Fluorescent scattering by molecules embedded in small particles. Progress report, February 1, 1981-January 31, 1982 (open access)

Fluorescent scattering by molecules embedded in small particles. Progress report, February 1, 1981-January 31, 1982

In earlier work a model of fluorescent and Raman scattering by active molecules represented as classical electric dipoles embedded in small particles was developed. The intensity and angular distribution of the inelastically scattered radiation was shown to depend on the geometric and optical properties of the particle. The model was originally developed for particles having spherical shape and later extended to concentric spheres, cylinders, and prolate spheroids. The active molecules were originally assumed to be isotropically polarizable. The model has been recently extended to certain types of anisotropically polarizable molecules. The model had also been applied to particles having internal structure.
Date: January 31, 1982
Creator: Chew, H. & McNulty, P.J.
System: The UNT Digital Library
Kinetics of Beta-14[14C] Carotene in a Human Subject Using Accelerator Mass Spectrometry (open access)

Kinetics of Beta-14[14C] Carotene in a Human Subject Using Accelerator Mass Spectrometry

{beta}-Carotene is a tetraterpenoid distributed widely throughout the plant kingdom. It is a member of a group of pigments referred to as carotenoids that have the distinction of serving as metabolic precursors to vitamin A in humans and many animals [1,2]. We used Accelerator Mass Spectrometry (AMS) [3] to determine the metabolic behavior of a physiologic oral dose of {beta}-[{sup 14}C]carotene (200 nanoCuries; 0.57 {micro}mol) in a healthy human subject. Serial blood specimens were collected for 210-d and complete urine and feces were collected for 17 and 10-d, respectively. Balance data indicated that the dose was 42% bioavailable. The absorbed {beta}-carotene was lost slowly via urine in accord with the slow body turnover of {beta}-carotene and vitamin A [4]. HPLC fractionation of plasma taken at early time points (0-24-h) showed the label was distributed between {beta}-carotene and retinyl esters (vitamin A) derived from intestinal metabolism.
Date: January 31, 2000
Creator: Dueker, S. R.; Lin, Y.; Follett, J. R.; Clifford, A. J. & Buchholz, B. A.
System: The UNT Digital Library
Status of the Canadian Situation Regarding Locomotive Emissions (open access)

Status of the Canadian Situation Regarding Locomotive Emissions

None
Date: January 31, 2001
Creator: Eggleton, P.
System: The UNT Digital Library
A Historical Profile of the Higgs Boson (open access)

A Historical Profile of the Higgs Boson

The Higgs boson was postulated in 1964, and phenomenological studies of its possible production and decays started in the early 1970s, followed by studies of its possible productionin e{sup +} e{sup -}, {anti p}p and pp collisions, in particular. Until recently, the most sensitive searches for the Higgs boson were at LEP between 1989 and 2000, which have been complemented bysearches at the Fermilab Tevatron. The LHC has recently entered the hunt, excluding a Higgs boson over a large range of masses and revealing a tantalizing hint in the range 119 to125 GeV, and there are good prospects that the existence or otherwise of the Higgs boson will soon be established. One of the most attractive possibilities is that the Higgs bosonis accompanied by supersymmetry, though composite options have yet to be excluded. This article reviews some of the key historical developments in Higgs physics over the past half-century.
Date: January 31, 2012
Creator: Ellis, John; Gaillard, Mary K. & Nanopoulos, Dimitri V.
System: The UNT Digital Library
Matching the Capabilities of Higher Education Institutions with the Technology Needs of the Y-12 National Security Complex (open access)
Steady-State Diffusion of Water through Soft-Contact LensMaterials (open access)

Steady-State Diffusion of Water through Soft-Contact LensMaterials

Water transport through soft contact lenses (SCL) is important for acceptable performance on the human eye. Chemical-potential gradient-driven diffusion rates of water through soft-contact-lens materials are measured with an evaporation-cell technique. Water is evaporated from the bottom surface of a lens membrane by impinging air at controlled flow rate and humidity. The resulting weight loss of a water reservoir covering the top surface of the contact-lens material is recorded as a function of time. New results are reported for a conventional hydrogel material (SofLens{trademark} One Day, hilafilcon A, water content at saturation W{sub 10} = 70 weight %) and a silicone hydrogel material (PureVision{trademark}, balafilcon A, W{sub 10} = 36 %), with and without surface oxygen plasma treatment. Also, previously reported data for a conventional HEMA-SCL (W{sub 10} = 38 %) hydrogel are reexamined and compared with those for SofLens{trademark} One Day and PureVision{trademark} hydrogels. Measured steady-state water fluxes are largest for SofLens{trademark} One Day, followed by PureVision{trademark} and HEMA. In some cases, the measured steady-state water fluxes increase with rising relative air humidity. This increase, due to an apparent mass-transfer resistance at the surface (trapping skinning), is associated with formation of a glassy skin at the air/membrane interface when …
Date: January 31, 2005
Creator: Fornasiero, Francesco; Krull, Florian; Radke, Clayton J. & Prausnitz, JohnM.
System: The UNT Digital Library