Resource Type

States

Language

Application of automated deduction to the search for single axioms for exponent groups (open access)

Application of automated deduction to the search for single axioms for exponent groups

We present new results in axiomatic group theory obtained by using automated deduction programs. The results include single axioms, some with the identity and others without, for groups of exponents 3, 4, 5 and 7, and a general form for single axioms for groups of odd exponent. The results were obtained by using the programs in three separate ways: as a symbolic calculator, to search for proofs,and to search for couterexamples. We also touch on relations between logic programming and automated reasoning.
Date: February 11, 1992
Creator: McCune, W. & Wos, L.
System: The UNT Digital Library
Low-exposure tritium radiotoxicity in mammals (open access)

Low-exposure tritium radiotoxicity in mammals

Studies of tritium radiotoxicity involving chronic /sup 3/H0H exposures in mammals demonstrate in both mice and monkeys that biological effects can be measured following remarkably low levels of exposure - levels in the range of serious practical interest to radiation protection. These studies demonstrate also that deleterious effects of /sup 3/H beta radiation do not differ significantly from those of gamma radiation at high exposures. In contrast, however, at low exposures tritium is significantly more effective than gamma rays, rad for rad, by a factor approaching 3. This is important for hazard evaluation and radiation protection because knowledge concerning biological effects of chronic low-level radiation exposure has come mainly from gamma-ray data; and predictions based on gamma-ray data will underestimate tritium effects - especially at low exposures - unless the RBE is fully taken into account.
Date: February 11, 1982
Creator: Dobson, R.L.
System: The UNT Digital Library
Mechanical model for ductility loss (open access)

Mechanical model for ductility loss

A mechanical model was constructed to probe into the mechanism of ductility loss. Fracture criterion based on critical localized deformation was undertaken. Two microstructure variables were considered in the model. Namely, the strength ratio of grain boundary affected area to the matrix, ..cap omega.., and the linear fraction, x, of grain boundary affected area. A parametrical study was carried out. The study shows that the ductility is very sensitive to those microstructure parameters. The functional dependence of ductility to temperature as well as strain-rate, suggested by the model, is demonstrated to be consistent with the observation.
Date: February 11, 1980
Creator: Hu, W.L.
System: The UNT Digital Library
Technical Risk Rating of DOE Environmental Projects - 9153 (open access)

Technical Risk Rating of DOE Environmental Projects - 9153

The U.S. Department of Energy's Office of Environmental Management (DOE-EM) was established to achieve the safe and compliant disposition of legacy wastes and facilities from defense nuclear applications. The scope of work is diverse, with projects ranging from single acquisitions to collections of projects and operations that span several decades and costs from hundreds of millions to billions US$. The need to be able to manage and understand the technical risks from the project to senior management level has been recognized as an enabler to successfully completing the mission. In 2008, DOE-EM developed the Technical Risk Rating as a new method to assist in managing technical risk based on specific criteria. The Technical Risk Rating, and the criteria used to determine the rating, provides a mechanism to foster open, meaningful communication between the Federal Project Directors and DOE-EM management concerning project technical risks. Four indicators (technical maturity, risk urgency, handling difficulty and resolution path) are used to focus attention on the issues and key aspects related to the risks. Pressing risk issues are brought to the forefront, keeping DOE-EM management informed and engaged such that they fully understand risk impact. Use of the Technical Risk Rating and criteria during reviews …
Date: February 11, 2009
Creator: Cercy, Michael; Fayfich, Ronald & Schneider, Steven
System: The UNT Digital Library
CLOMP: Accurately Characterizing OpenMP Application Overheads (open access)

CLOMP: Accurately Characterizing OpenMP Application Overheads

Despite its ease of use, OpenMP has failed to gain widespread use on large scale systems, largely due to its failure to deliver sufficient performance. Our experience indicates that the cost of initiating OpenMP regions is simply too high for the desired OpenMP usage scenario of many applications. In this paper, we introduce CLOMP, a new benchmark to characterize this aspect of OpenMP implementations accurately. CLOMP complements the existing EPCC benchmark suite to provide simple, easy to understand measurements of OpenMP overheads in the context of application usage scenarios. Our results for several OpenMP implementations demonstrate that CLOMP identifies the amount of work required to compensate for the overheads observed with EPCC. Further, we show that CLOMP also captures limitations for OpenMP parallelization on NUMA systems.
Date: February 11, 2008
Creator: Bronevetsky, G; Gyllenhaal, J & de Supinski, B
System: The UNT Digital Library
Demonstartion of density dependence of x-ray flux in a laser-driven hohlraum (open access)

Demonstartion of density dependence of x-ray flux in a laser-driven hohlraum

Experiments have been conducted using laser-driven cylindrical hohlraums whose walls are machined from Ta{sub 2}O{sub 5} foams of 100 mg/cc and 4 g/cc densities. Measurements of the radiation temperature demonstrate that the lower density walls produce higher radiation temperatures than the high density walls. This is the first experimental demonstration of the prediction that this would occur [M. D. Rosen and J. H. Hammer, Phys. Rev. E 72, 056403 (2005)]. For high density walls, the radiation front propagates subsonically, and part of the absorbed energy is wasted by the flow kinetic energy. For the lower wall density, the front velocity is supersonic and can devote almost all of the absorbed energy to heating the wall.
Date: February 11, 2008
Creator: Young, P E; Rosen, M D; Hammer, J H; Hsing, W S; Glendinning, S G; Turner, R E et al.
System: The UNT Digital Library
Thermal Cycling on Fatigue Failure of the Plutonium Vitrification Melter (open access)

Thermal Cycling on Fatigue Failure of the Plutonium Vitrification Melter

One method for disposition of excess plutonium is vitrification into cylindrical wasteforms. Due to the hazards of working with plutonium, the vitrification process must be carried out remotely in a shielded environment. Thus, the equipment must be easily maintained. With their simple design, induction melters satisfy this criterion, making them ideal candidates for plutonium vitrification. However, due to repeated heating and cooling cycles and differences in coefficients of thermal expansion of contacting materials fatigue failure of the induction melter is of concern. Due to the cost of the melter, the number of cycles to failure is critical. This paper presents a method for determining the cycles to failure for an induction melter by using the results from thermal and structural analyses as input to a fatigue failure model.
Date: February 11, 2009
Creator: Jordan, Jeffrey & Gorczyca, Jennifer
System: The UNT Digital Library
Asymmetric injection of cathodic arc plasma into a macroparticlefilter (open access)

Asymmetric injection of cathodic arc plasma into a macroparticlefilter

The cathodic arc plasmas produced by cathode spots usuallyinclude macroparticles, which is undesirable for many applications. Acommon way of removing macroparticles is to use curved solenoid filterswhich guide the plasma from the source to the substrate. In this work, anarc source with relatively small cathode is used, limiting the possiblelocations of plasma production. The relative position of cathodic arcsource and macroparticle filtered was systematically varied and thefiltered plasma current was recorded. It was found that axis-symmetricplasma injection leads to maximum throughput only if an anode aperturewas used, which limited the plasma to near-axis flow by scraping offplasma at larger angles to the axis. When the anode aperture was removed,more plasma could enter the filter. In this case, maximum filtered ioncurrent was achieved when the plasma was injected off-axis, namely offsetin the direction where the filter is curved. Such behavior wasanticipated because the plasma column in the filter is known to beshifted by ExB and centrifugal drift as well as by non-axis-symmetriccomponents of the magnetic field in the filter entrance and exit plane.The data have implications for plasma transport variations caused bydifferent spot locations on cathodes that are not small compared to thefilter cross section.
Date: February 11, 2004
Creator: Anders, Andre & MacGill, Robert A.
System: The UNT Digital Library
Enhanced Chemical Cleaning: A New Process for Chemically Cleaning Savannah River Waste Tanks (open access)

Enhanced Chemical Cleaning: A New Process for Chemically Cleaning Savannah River Waste Tanks

At the Savannah River Site (SRS) there are 49 High Level Waste (HLW) tanks that eventually must be emptied, cleaned, and closed. The current method of chemically cleaning SRS HLW tanks, commonly referred to as Bulk Oxalic Acid Cleaning (BOAC), requires about a half million liters (130,000 gallons) of 8 weight percent (wt%) oxalic acid to clean a single tank. During the cleaning, the oxalic acid acts as the solvent to digest sludge solids and insoluble salt solids, such that they can be suspended and pumped out of the tank. Because of the volume and concentration of acid used, a significant quantity of oxalate is added to the HLW process. This added oxalate significantly impacts downstream processing. In addition to the oxalate, the volume of liquid added competes for the limited available tank space. A search, therefore, was initiated for a new cleaning process. Using TRIZ (Teoriya Resheniya Izobretatelskikh Zadatch or roughly translated as the Theory of Inventive Problem Solving), Chemical Oxidation Reduction Decontamination with Ultraviolet Light (CORD-UV{reg_sign}), a mature technology used in the commercial nuclear power industry was identified as an alternate technology. Similar to BOAC, CORD-UV{reg_sign} also uses oxalic acid as the solvent to dissolve the metal (hydr)oxide …
Date: February 11, 2009
Creator: Ketusky, Edward; Spires, Renee & Davis, Neil
System: The UNT Digital Library
Damage Detection System with Sub-microsecond Resolution (open access)

Damage Detection System with Sub-microsecond Resolution

Fiber optic grating sensors have been used to measure multi-dimensional strain, pressure, temperature, corrosion and moisture. This paper presents a method of using fiber grating sensors to measure the position and velocity of a very fast event associated with a blast wave. A chirped fiber grating of 50 mm length is placed in a highly energetic material. The action of the shock wave is to destroy the fiber grating as it propagates along it. By using a spectral filter such as a chirped fiber grating in combination with high speed detectors the position and velocity of the shock wave may be determined. A layout of a system used to experimentally verify this technique is described and results presented for two different highly energetic materials.
Date: February 11, 2008
Creator: Udd, E & Benterou, J
System: The UNT Digital Library
Salt Processing Through Ion Exchange at the Savannah River Site Selection of Exchange Media and Column Configuration - 9198 (open access)

Salt Processing Through Ion Exchange at the Savannah River Site Selection of Exchange Media and Column Configuration - 9198

The Department of Energy (DOE) has developed, modeled, and tested several different ion exchange media and column designs for cesium removal. One elutable resin and one non-elutable resin were considered for this salt processing application. Deployment of non-elutable Crystalline Silicotitanate and elutable Resorcinol Formaldehyde in several different column configurations were assessed in a formal Systems Engineering Evaluation (SEE). Salt solutions were selected that would allow a grouping of non-compliant tanks to be closed. Tests were run with the elutable resin to determine compatibility with the resin configuration required for an in-tank ion exchange system. Models were run to estimate the ion exchange cycles required with the two resins in several column configurations. Material balance calculations were performed to estimate the impact on the High Level Waste (HLW) system at the Savannah River Site (SRS). Conceptual process diagrams were used to support the hazard analysis. Data from the hazard analysis was used to determine the relative impact on safety. This report will discuss the technical inputs, SEE methods, results and path forward to complete the technical maturation of ion exchange.
Date: February 11, 2009
Creator: Spires, Renee; Punch, Timothy & McCabe, Daniel
System: The UNT Digital Library
Conformal Field Theories: From Old to New (open access)

Conformal Field Theories: From Old to New

In a short review of recent work, we discuss the general problem of constructing the actions of new conformal field theories from old conformal field theories. Such a construction follows when the old conformal field theory admits new conformal stress tensors in its chiral algebra, and it turns out that the new conformal field theory is generically a new spin-two gauge theory. As an example we discuss the new spin-two gauged sigma models which arise in this fashion from the general conformal non-linear sigma model.
Date: February 11, 1998
Creator: Halpern, M. B. & Schwartz, C.
System: The UNT Digital Library
Peroxotitanates for Biodelivery of Metals (open access)

Peroxotitanates for Biodelivery of Metals

Metal-based drugs are largely undeveloped in pharmacology. One limiting factor is the systemic toxicity of metal-based compounds. A solid-phase, sequestratable delivery agent for local delivery of metals could reduce systemic toxicity, facilitating new drug development in this nascent area. Amorphous peroxotitanates (APT) are ion exchange materials with high affinity for several heavy metal ions, and have been proposed to deliver or sequester metal ions in biological contexts. In the current study, we tested a hypothesis that APT are able to deliver metals or metal compounds to cells. We exposed fibroblasts (L929) or monocytes (THP1) to metal-APT materials for 72 h in vitro, then measured cellular mitochondrial activity (SDH-MTT method) to assess the biological impact of the metal-APT materials vs. metals or APT alone. APT alone did not significantly affect cellular mitochondrial activity, but all metal-APT materials suppressed the mitochondrial activity of fibroblasts (by 30-65% of controls). The concentration of metal-APT materials required to suppress cellular mitochondrial activity was below that required for metals alone, suggesting that simple extracellular release of the metals from the metal-APT materials was not the primary mechanism of mitochondrial suppression. In contrast to fibroblasts, no metal-APT material had a measurable effect on THP1 monocyte mitochondrial activity, …
Date: February 11, 2009
Creator: Hobbs, David & Elvington, M.
System: The UNT Digital Library
Results from a Prototype MAPS Sensor Telescope and Readout Systemwith Zero Suppression for the Heavy Flavor Tracker at STAR (open access)

Results from a Prototype MAPS Sensor Telescope and Readout Systemwith Zero Suppression for the Heavy Flavor Tracker at STAR

We describe a three Mimostar-2 Monolithic Active PixelSensor (MAPS) sensor telescope prototype with an accompanying readoutsystem incorporating on-the-fly data sparsification. The system has beencharacterized and we report on the measured performance of the sensortelescope and readout system in beam tests conducted both at the AdvancedLight Source (ALS) at Lawrence Berkeley National Laboratory (LBNL) and inthe STAR experiment at the Relativistic Heavy Ion Collider (RHIC). Thiseffort is part of the development and prototyping work that will lead toa vertex detector for the STAR experiment.
Date: February 11, 2008
Creator: Greiner, Leo C.; Matis, Howard S.; Ritter, Hans G.; Rose, AndrewA.; Stezelberger, Thorsten; Sun, Xiangming et al.
System: The UNT Digital Library
Prospecting for lunar ice using a multi-rover cooperative team (open access)

Prospecting for lunar ice using a multi-rover cooperative team

A multi-rover cooperative team or swarm developed by Sandia National Laboratories is described, including various control methodologies that have been implemented to date. How the swarm's capabilities could be applied to a lunar ice prospecting mission is briefly explored. Some of the specific major engineering issues that must be addressed to successfully implement the swarm approach to a lunar surface mission are outlined, and potential solutions are proposed.
Date: February 11, 2000
Creator: Klarer, Paul R.; Feddema, John T. & Lewis, Christopher L.
System: The UNT Digital Library
Radial implosion acceleration (open access)

Radial implosion acceleration

A scheme to generate high accelerating gradients (approximately (approx.) a few gigaelectronvolts per meter) is described. The acceleration is nonresonant so that staging may be fairly easy, and the energy source is relativistic e-beams so that a relatively high over all efficiency may be achievable.
Date: February 11, 1985
Creator: Channell, P.J.
System: The UNT Digital Library
Magnetic mirror fusion: status and prospects (open access)

Magnetic mirror fusion: status and prospects

Two improved mirror systems, the tandem mirror (TM) and the field-reversed mirror (FRM) are being intensively studied. The twin practical aims of these studies: to improve the economic prospects for mirror fusion power plants and to reduce the size and/or complexity of such plants relative to earlier approaches to magnetic fusion. While at the present time the program emphasis is still strongly oriented toward answering scientific questions, the emphasis is shifting as the data accumulates and as larger facilities - ones with a heavy technological and engineering orientation - are being prepared. The experimental and theoretical progress that led to the new look in mirror fusion research is briefly reviewed, the new TM and the FRM ideas are outlined, and the projected future course of mirror fusion research is discussed.
Date: February 11, 1980
Creator: Post, Richard F.
System: The UNT Digital Library
HIJET with AGS physics and N[sup *]'s (open access)

HIJET with AGS physics and N[sup *]'s

We investigate the effects of secondary interactions in nucleus- nucleus and proton-nucleus collisions using a modified HIJET Monte Carlo generator. The effects of N[sup *] production is explored and it is found that the numbers of kaons can almost be explained by their inclusion. However the transverse momentum spectrum of the kaons is not explained, since their production in HIJET is a soft secondary scattering process and not a hot thermal process like the data.
Date: February 11, 1993
Creator: Longacre, R. S.
System: The UNT Digital Library
Neutral strange particle production at the AGS (open access)

Neutral strange particle production at the AGS

We present the results of [Lambda] and K[sub s[sup o]] production from Si and Pb targets with 14.6[times][Lambda] Gev/c Si beams. The measured rapidity distributions and the transverse mass exponential slopes are presented and compared with models.
Date: February 11, 1993
Creator: Saulys, A.C.
System: The UNT Digital Library
Probing electroweak symmetry breaking at the SSC (Superconducting Super Collider): A no-lose corollary (open access)

Probing electroweak symmetry breaking at the SSC (Superconducting Super Collider): A no-lose corollary

Low energy theorems are derived for scattering of longitudinally polarized W and Z's, providing the basis for an estimate of the observable signal at the SSC if electroweak symmetry breaking is due to new physics at the TeV scale.
Date: February 11, 1987
Creator: Chanowitz, Michael S.
System: The UNT Digital Library
Application of automated deduction to the search for single axioms for exponent groups (open access)

Application of automated deduction to the search for single axioms for exponent groups

We present new results in axiomatic group theory obtained by using automated deduction programs. The results include single axioms, some with the identity and others without, for groups of exponents 3, 4, 5 and 7, and a general form for single axioms for groups of odd exponent. The results were obtained by using the programs in three separate ways: as a symbolic calculator, to search for proofs,and to search for couterexamples. We also touch on relations between logic programming and automated reasoning.
Date: February 11, 1992
Creator: McCune, W. & Wos, L.
System: The UNT Digital Library
ESCAPAID Project Plan: (ESCAPAID = Electronic Systems Contract Administration Payment And Invoicing Database) (open access)

ESCAPAID Project Plan: (ESCAPAID = Electronic Systems Contract Administration Payment And Invoicing Database)

The Electronic Systems Contract Administration Payment And Invoicing Database (ESCAPAID) project is a cooperative effort to simplify and automate the contracting and billing of services between Digital Equipment Corporation (Digital) and Los Alamos National Laboratory (LANL).The ESCAPAID project is intended to improve productivity in both organizations by reducing the inaccuracies and the amount of manual effort in the current system. Within LANL, the project is intended to streamline operations for purchasing (N4AT Division), finance (FIN Division), and Laboratory personnel requesting maintenance contract services from Digital. In October 1992, Digital and LANL released a jointly developed Program Definition, which provides an overview of the proposed system and an eight-step strategy for implementing a preliminary model.The second step of this strategy calls for the development of a model plan, including a description of afl high-level tasks that need to be completed and a series of Gantt and PERT charts. In order to accomplish this step, representatives from Digital and LANL participated in a Joint Application Development (JAD) workshop on January 19 and 20, 1993. The results of the workshop are reflected in this document.
Date: February 11, 1993
Creator: Lane, T. A.
System: The UNT Digital Library
Neutral strange particle production at the AGS (open access)

Neutral strange particle production at the AGS

We present the results of {Lambda} and K{sub s{sup o}} production from Si and Pb targets with 14.6{times}{Lambda} Gev/c Si beams. The measured rapidity distributions and the transverse mass exponential slopes are presented and compared with models.
Date: February 11, 1993
Creator: Saulys, A. C. & Collaboration, For the E810
System: The UNT Digital Library
HIJET with AGS physics and N{sup *}`s (open access)

HIJET with AGS physics and N{sup *}`s

We investigate the effects of secondary interactions in nucleus- nucleus and proton-nucleus collisions using a modified HIJET Monte Carlo generator. The effects of N{sup *} production is explored and it is found that the numbers of kaons can almost be explained by their inclusion. However the transverse momentum spectrum of the kaons is not explained, since their production in HIJET is a soft secondary scattering process and not a hot thermal process like the data.
Date: February 11, 1993
Creator: Longacre, R. S.
System: The UNT Digital Library