Waveforms Measured in Confined Thermobaric Explosion (open access)

Waveforms Measured in Confined Thermobaric Explosion

Experiments with 1.5-g Shock-Dispersed-Fuel (SDF) charges have been conducted in six different chambers. Both flake Aluminum and TNT were used as the fuel. Static pressure gauges on the chamber wall were the main diagnostic. Waveforms for explosions in air were significantly larger than those in nitrogen - thereby demonstrating a strong thermobaric (combustion) effect. This effect increases as the confinement volume decreases and the mixture richness approaches 1.
Date: May 4, 2007
Creator: Reichenbach, H; Neuwald, P & Kuhl, A L
Object Type: Article
System: The UNT Digital Library
Long-Term Corrosion Tests of Prototypical SAM2X5 (Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4) Coatings (open access)

Long-Term Corrosion Tests of Prototypical SAM2X5 (Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4) Coatings

An iron-based amorphous metal with good corrosion resistance and a high absorption cross-section for thermal neutrons has been developed and is reported here. This amorphous alloy has the approximate formula 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} and is known as SAM2X5. Chromium (Cr), molybdenum (Mo) and tungsten (W) were added to provide corrosion resistance, while boron (B) was added to promote glass formation and the absorption of thermal neutrons. Since this amorphous metal has a higher boron content than conventional borated stainless steels, it provides the nuclear engineer with design advantages for criticality control structures with enhanced safety. While melt-spun ribbons with limited practical applications were initially produced, large quantities (several tons) of gas atomized powder have now been produced on an industrial scale, and applied as thermal-spray coatings on prototypical half-scale spent nuclear fuel containers and neutron-absorbing baskets. These prototypes and other SAM2X5 samples have undergone a variety of corrosion testing, including both salt-fog and long-term immersion testing. The modes and rates of corrosion have been determined in the various environments, and are reported here. While these coatings have less corrosion resistance than melt-spun ribbons and optimized coatings produced in the laboratory, substantial corrosion resistance has …
Date: May 10, 2007
Creator: Farmer, J C; Choi, J S; Saw, C K; Rebak, R H; Day, S D; Lian, T et al.
Object Type: Report
System: The UNT Digital Library
Modeling RHIC Linear Chromaticity with Sextupole Components in the Arc Main Dipoles (open access)

Modeling RHIC Linear Chromaticity with Sextupole Components in the Arc Main Dipoles

N/A
Date: May 1, 2007
Creator: Y., Luo; Jain, A.; Fischer, W.; Tepikian, S. & Trbojevic, D.
Object Type: Report
System: The UNT Digital Library
Beam Studies on the AGS Polarized Proton 2006 Extraction Porch Part 1 (open access)

Beam Studies on the AGS Polarized Proton 2006 Extraction Porch Part 1

N/A
Date: May 1, 2007
Creator: L., Ahrens
Object Type: Report
System: The UNT Digital Library
Numerical Simulations of Thermobaric Explosions (open access)

Numerical Simulations of Thermobaric Explosions

A Model of the energy evolution in thermobaric explosions is presented. It is based on the two-phase formulation: conservation laws for the gas and particle phases along with inter-phase interaction terms. It incorporates a Combustion Model based on the mass conservation laws for fuel, air and products; source/sink terms are treated in the fast-chemistry limit appropriate for such gas dynamic fields. The Model takes into account both the afterburning of the detonation products of the booster with air, and the combustion of the fuel (Al or TNT detonation products) with air. Numerical simulations were performed for 1.5-g thermobaric explosions in five different chambers (volumes ranging from 6.6 to 40 liters and length-to-diameter ratios from 1 to 12.5). Computed pressure waveforms were very similar to measured waveforms in all cases - thereby proving that the Model correctly predicts the energy evolution in such explosions. The computed global fuel consumption {mu}(t) behaved as an exponential life function. Its derivative {dot {mu}}(t) represents the global rate of fuel consumption. It depends on the rate of turbulent mixing which controls the rate of energy release in thermobaric explosions.
Date: May 4, 2007
Creator: Kuhl, A L; Bell, J B; Beckner, V E & Khasainov, B
Object Type: Article
System: The UNT Digital Library
Quantitative tunneling spectroscopy of nanocrystals (open access)

Quantitative tunneling spectroscopy of nanocrystals

The proposed goals of this collaborative work were to systematically characterize the electronic structure and dynamics of 3-dimensional metal and semiconducting nanocrystals using scanning tunneling microscopy/spectroscopy (STM/STS) and ballistic electron emission spectroscopy (BEES). This report describes progress in the spectroscopic work and in the development of methods for creating and characterizing gold nanocrystals. During the grant period, substantial effort also was devoted to the development of epitaxial graphene (EG), a very promising materials system with outstanding potential for nanometer-scale ballistic and coherent devices ("graphene" refers to one atomic layer of graphitic, sp2 -bonded carbon atoms [or more loosely, few layers]). Funding from this DOE grant was critical for the initial development of epitaxial graphene for nanoelectronics
Date: May 25, 2007
Creator: First, Phillip N; Whetten, Robert L & Schaaff, T Gregory
Object Type: Report
System: The UNT Digital Library
A cable SGEMP tutorial : running CEPXS, CEPTRE and EMPHASIS/CABANA to evaluate the electrical response of a cable. (open access)

A cable SGEMP tutorial : running CEPXS, CEPTRE and EMPHASIS/CABANA to evaluate the electrical response of a cable.

This tutorial is aimed at guiding a user through the process of performing a cable SGEMP simulation. The tutorial starts with processing a differential photon spectrum obtained from a Monte Carlo code such as ITS into a discrete (multi-group) spectrum used in CEPXS and CEPTRE. Guidance is given in the creation of a nite element mesh of the cable geometry. The set-up of a CEPTRE simulation is detailed. Users are instructed in evaluating the quality of the CEPTRE radiation transport results. The post-processing of CEPTRE results using Exostrip is detailed. And finally, an EMPHASIS/CABANA simulation is detailed including the interpretation of the output.
Date: May 1, 2007
Creator: Liscum-Powell, Jennifer L.; Bohnhoff, William J. & Turner, C. David
Object Type: Report
System: The UNT Digital Library
Quadractic Model of Thermodynamic States in SDF Explosions (open access)

Quadractic Model of Thermodynamic States in SDF Explosions

We study the thermodynamic states encountered during Shock-Dispersed-Fuel (SDF) explosions. Such explosions contain up to six components: three fuels (PETN, TNT and Aluminum) and their products corresponding to stoichiometric combustion with air. We establish the loci in thermodynamic state space that correctly describes the behavior of the components. Results are fit with quadratic functions that serve as fast equations of state suitable for 3D numerical simulations of SDF explosions.
Date: May 4, 2007
Creator: Kuhl, A L & Khasainov, B
Object Type: Article
System: The UNT Digital Library
A Collection of Features for Semantic Graphs (open access)

A Collection of Features for Semantic Graphs

Semantic graphs are commonly used to represent data from one or more data sources. Such graphs extend traditional graphs by imposing types on both nodes and links. This type information defines permissible links among specified nodes and can be represented as a graph commonly referred to as an ontology or schema graph. Figure 1 depicts an ontology graph for data from National Association of Securities Dealers. Each node type and link type may also have a list of attributes. To capture the increased complexity of semantic graphs, concepts derived for standard graphs have to be extended. This document explains briefly features commonly used to characterize graphs, and their extensions to semantic graphs. This document is divided into two sections. Section 2 contains the feature descriptions for static graphs. Section 3 extends the features for semantic graphs that vary over time.
Date: May 2, 2007
Creator: Eliassi-Rad, T.; Fodor, I. K. & Gallagher, B.
Object Type: Report
System: The UNT Digital Library
XRD Technique: A way to disseminate structural changes in iron-based amorphous materials (open access)

XRD Technique: A way to disseminate structural changes in iron-based amorphous materials

Prevention of corrosion is a vital goal for the Department of Defense when billions of dollars are spent every year. Corrosion resistant materials have applications in all sort of military vehicles, and more importantly in naval vessels and submarines which come in contact with the seawater. It is known that corrosion resistance property can be improved by the used of structurally designed materials in the amorphous state where the atoms are arranged in a non-periodic fashion and specific atoms, tailored to the required properties can be interjected into the matrix for specific application. The XRD techniques reported here is to demonstrate the optimal conditions for characterization of these materials. The samples, which normally contain different compositions of Fe, Cr, B, Mo, Y, Mn, Si and W, are in the form of powders, ribbons and coatings. These results will be compared for the different forms of the sample which appears to correlate to the cooling rate during sample processing. In most cases, the materials are amorphous or amorphous with very small amount of crystallinity. In the ribbon samples for different compositions we observed that the materials are essentially amorphous. In most cases, starting from an amorphous powder sample, the coatings are …
Date: May 24, 2007
Creator: Saw, C. K.; Lian, T.; Day, D. & Farmer, J.
Object Type: Article
System: The UNT Digital Library
Full System Model of Magnetron Sputter Chamber - Proof-of-Principle Study (open access)

Full System Model of Magnetron Sputter Chamber - Proof-of-Principle Study

The lack of detailed knowledge of internal process conditions remains a key challenge in magnetron sputtering, both for chamber design and for process development. Fundamental information such as the pressure and temperature distribution of the sputter gas, and the energies and arrival angles of the sputtered atoms and other energetic species is often missing, or is only estimated from general formulas. However, open-source or low-cost tools are available for modeling most steps of the sputter process, which can give more accurate and complete data than textbook estimates, using only desktop computations. To get a better understanding of magnetron sputtering, we have collected existing models for the 5 major process steps: the input and distribution of the neutral background gas using Direct Simulation Monte Carlo (DSMC), dynamics of the plasma using Particle In Cell-Monte Carlo Collision (PIC-MCC), impact of ions on the target using molecular dynamics (MD), transport of sputtered atoms to the substrate using DSMC, and growth of the film using hybrid Kinetic Monte Carlo (KMC) and MD methods. Models have been tested against experimental measurements. For example, gas rarefaction as observed by Rossnagel and others has been reproduced, and it is associated with a local pressure increase of {approx}50% …
Date: May 4, 2007
Creator: Walton, C.; Gilmer, G.; Zepeda-Ruiz, L.; Wemhoff, A. & Barbee, T.
Object Type: Article
System: The UNT Digital Library
Colloid-Facilitated Radionuclide Transport in Fractured Carbonate Rock from Yucca Flat, Nevada National Security Site (open access)

Colloid-Facilitated Radionuclide Transport in Fractured Carbonate Rock from Yucca Flat, Nevada National Security Site

None
Date: May 29, 2007
Creator: Zavarin, M.; Roberts, S. K.; Johnson, M. R.; Hu, Q.; Powell, B. A.; Zhao, P. et al.
Object Type: Report
System: The UNT Digital Library
Recommendations for new monitoring wells at Everest, Kansas. (open access)

Recommendations for new monitoring wells at Everest, Kansas.

On February 15, 2007, the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) submitted Recommendations for Remedial Action at Everest, Kansas. Those Recommendations were accepted by the Kansas Department of Health and Environment (KDHE) in a letter to the CCC/USDA dated March 5, 2007. The approved Recommendations document outlines a plan for systematic groundwater sampling and monitoring at Everest to provide data necessary for the critical evaluation of remedial options - including a phytoremediation alternative - for restoration of the groundwater and protection of the surface waters of the intermittent creek at this site. Phase I of the KDHE-approved monitoring plan includes the following activities: (1) Groundwater sampling at existing monitoring wells, with analyses for volatile organic compounds (VOCs) and selected biodegradation parameters; (2) Sampling of surface waters along the intermittent creek for VOCs analyses; and (3) Periodic manual measurement and automated recording of groundwater and surface water levels in the vicinity of the intermittent creek. The locations selected for groundwater and surface water sampling and analyses under the approved monitoring program were determined in consultation with the KDHE. As a result of subsequent discussions among representatives of the KDHE, the CCC/USDA, and Argonne regarding the technical program …
Date: May 3, 2007
Creator: LaFreniere, L. M.
Object Type: Report
System: The UNT Digital Library
Microbial Diversity-Based Novel Crop Protection Products (open access)

Microbial Diversity-Based Novel Crop Protection Products

Extremophilic microorganisms are adapted to survive in ecological niches with high temperatures, extremes of pH, high salt concentrations, high pressure, radiation, etc. Extremophiles produce unique biocatalysts and natural products that function under extreme conditions comparab le to those prevailing in various industrial processes. Therefore, there is burgeoning interest in bioprospecting for extremophiles with potential immediate use in agriculture, the food, chemical, and pharm aceutical industries, and environmental biotechnology. Over the years, several thousand extremophilic bacteria, archaea, and filamentous fungi were collected at extreme environmental sites in the USA, the Chernobyl Exclusion Zone surrounding the faeild nuclear power plant in Ukraine, in and around Lake Baikal in Siberia, and at geothermal sites on the Kamchatka peninsula in Russia. These organisms were cultured under proprietary conditions, and the cell- free supernatants were screened for biological activities against plant pathogenic fungi and major crop damaging insects. Promising peptide lead molecules were isolated, characterized, and sequenced. Relatively high hit rates characterized the tested fermentation broths. Of the 26,000 samples screened, over thousand contained biological activity of interest. A fair number of microorganisms expressed broad- spectrum antifungal or insecticidal activity. Two- dozen broadly antifungal peptides (AFPs) are alr eady patent protected, and many more tens …
Date: May 10, 2007
Creator: Inc., Pioneer Hi-Bred International; Station, DuPont Experimental; Yalpani, Ronald Flannagan, Rafael Herrmann, James Presnail, Tamas Torok, and Nasser; Herrmann, Rafael; Presnail, James; Torok, Tamas et al.
Object Type: Article
System: The UNT Digital Library
Biological Sciences for the 21st Century: Meeting the Challenges of Sustainable Development in an Era of Global Change (open access)

Biological Sciences for the 21st Century: Meeting the Challenges of Sustainable Development in an Era of Global Change

The symposium was held 10-12 May, 2007 at the Capitol Hilton Hotel in Washington, D. C. The 30 talks explored how some of today's key biological research developments (such as biocomplexity and complex systems analysis, bioinformatics and computational biology, the expansion of molecular and genomics research, and the emergence of other comprehensive or system wide analyses, such as proteomics) contribute to sustainability science. The symposium therefore emphasized the challenges facing agriculture, human health, sustainable energy, and the maintenance of ecosystems and their services, so as to provide a focus and a suite of examples of the enormous potential contributions arising from these new developments in the biological sciences. This symposium was the first to provide a venue for exploring how the ongoing advances in the biological sciences together with new approaches for improving knowledge integration and institutional science capacity address key global challenges to sustainability. The speakers presented new research findings, and identified new approaches and needs in biological research that can be expected to have substantial impacts on sustainability science.
Date: May 12, 2007
Creator: Cracraft, Joel & O'Grady, Richard
Object Type: Report
System: The UNT Digital Library
Topical report : CFD analysis for the applicability of the natural convection shutdown heat removal test facility (NSTF) for the simulation of the VHTR RCCS. (open access)

Topical report : CFD analysis for the applicability of the natural convection shutdown heat removal test facility (NSTF) for the simulation of the VHTR RCCS.

The Very High Temperature gas cooled reactor (VHTR) is one of the GEN IV reactor concepts that have been proposed for thermochemical hydrogen production and other process-heat applications like coal gasification. The United States Department of Energy has selected the VHTR for further research and development, aiming to demonstrate emissions-free electricity and hydrogen production at a future time. One of the major safety advantages of the VHTR is the potential for passive decay heat removal by natural circulation of air in a Reactor Cavity Cooling System (RCCS). The air-side of the RCCS is very similar to the Reactor Vessel Auxiliary Cooling System (RVACS) that has been proposed for the PRISM reactor design. The design and safety analysis of the RVACS have been based on extensive analytical and experimental work performed at ANL. The Natural Convection Shutdown Heat Removal Test Facility (NSTF) at ANL that simulates at full scale the air-side of the RVACS was built to provide experimental support for the design and analysis of the PRISM RVACS system. The objective of this work is to demonstrate that the NSTF facility can be used to generate RCCS experimental data: to validate CFD and systems codes for the analysis of the …
Date: May 16, 2007
Creator: Tzanos, C. P. (Nuclear Engineering Division)
Object Type: Report
System: The UNT Digital Library
Introduction to Commercial Building Control Strategies and Techniques for Demand Response -- Appendices (open access)

Introduction to Commercial Building Control Strategies and Techniques for Demand Response -- Appendices

There are 3 appendices listed: (A) DR strategies for HVAC systems; (B) Summary of DR strategies; and (C) Case study of advanced demand response.
Date: May 1, 2007
Creator: Motegi, N.; Piette, M. A.; Watson, D. S.; Kiliccote, S. & Xu, P.
Object Type: Report
System: The UNT Digital Library
Ecological Data in Support of the Tank Closure and Waste Management Environmental Impact Statement. Part 2: Results of Spring 2007 Field Surveys (open access)

Ecological Data in Support of the Tank Closure and Waste Management Environmental Impact Statement. Part 2: Results of Spring 2007 Field Surveys

This review provides an evaluation of potential impacts of actions that have been proposed under various alternatives to support the closure of the high level waste tanks on the Hanford Site. This review provides a summary of data collected in the field during the spring of 2007 at all of the proposed project sites within 200 East and 200 West Areas, and at sites not previously surveyed. The primary purpose of this review is to provide biological data that can be incorporated into or used to support the Tank Closure and Waste Management Environmental Impact Statement.
Date: May 31, 2007
Creator: Sackschewsky, Michael R. & Downs, Janelle L.
Object Type: Report
System: The UNT Digital Library
Deviation of Nuclear Radii from a Smooth A Dependence for Neutron Data (open access)

Deviation of Nuclear Radii from a Smooth A Dependence for Neutron Data

None
Date: May 29, 2007
Creator: Dietrich, F. S.; Anderson, J. D.; Bauer, R. W.; Girod, M.; Gogny, D.; Grimes, S. M. et al.
Object Type: Article
System: The UNT Digital Library
Simulation of Aluminum Combustion and PETN Afterburning in a Confined Explosion (open access)

Simulation of Aluminum Combustion and PETN Afterburning in a Confined Explosion

None
Date: May 31, 2007
Creator: Kuhl, A L; Bell, J B; Beckner, V E & Khasainov, B
Object Type: Article
System: The UNT Digital Library
Afterburning and Combustion in Explosions in Barometric Calorimeters (open access)

Afterburning and Combustion in Explosions in Barometric Calorimeters

None
Date: May 31, 2007
Creator: Reichenbach, H; Neuwald, P & Kuhl, A L
Object Type: Article
System: The UNT Digital Library
Physiology and Regulation of Calcium Channels in Stomatal Guard Cells (open access)

Physiology and Regulation of Calcium Channels in Stomatal Guard Cells

Stomatal pores in the epidermis of leaves regulate the diffusion of CO2 into leaves for photosynthetic carbon fixation and control water loss of plants during drought periods. Guard cells sense CO2, water status, light and other environmental conditions to regulate stomatal apertures for optimization of CO2 intake and plant growth under drought stress. The cytosolic second messenger calcium contributes to stomatal movements by transducing signals and regulating ion channels in guard cells. Studies suggest that both plasma membrane Ca2+ influx channels and vacuolar/organellar Ca2+ release channels contribute to ABA-induced Ca2+ elevations in guard cells. Recent research in the P.I.'s laboratory has led to identification of a novel major cation-selective Ca2+-permeable influx channel (Ica) in the plasma membrane of Arabidopsis guard cells. These advances will allow detailed characterization of Ica plasma membrane Ca2+ influx channels in guard cells. The long term goal of this research project is to gain a first detailed characterization of these novel plasma membrane Ca2+-permeable channel currents in Arabidopsis guard cells. The proposed research will investigate the hypothesis that Ica represents an important Ca2+ influx pathway for ABA and CO2 signal transduction in Arabidopsis guard cells. These studies will lead to elucidation of key signal transduction mechanisms …
Date: May 2, 2007
Creator: Schroeder, Julian I.
Object Type: Report
System: The UNT Digital Library
Quarkonium shadowing in pPb and Pb+Pb collisions (open access)

Quarkonium shadowing in pPb and Pb+Pb collisions

The d+Au data from RHIC, including the pA results from the fixed-target CERN SPS pA data, suggest increased importance of initial-state shadowing and decreasing nuclear absorption with increasing energy. This is not surprising since smaller x is probed at higher energy while absorption due to multiple scattering is predicted to decrease with energy. The CERN SPS data suggest a J/{psi} absorption cross section of about 4 mb without shadowing, and a larger absorption cross section if it is included since the SPS x range is in the antishadowing region. The d+Au RHIC data support smaller absorption, {sigma}{sup J/{psi}}{sub abs} {approx} 0-2 mb. Thus our predictions for J/{psi} and {Upsilon} production in pPb and Pb+Pb interactions at the LHC are shown for initial-state shadowing alone with no absorption or dense matter effects. We note that including absorption would only move the calculated ratios down in proportion to the absorption survival probability since, at LHC energies, any rapidity dependence of absorption is at very large |y|, outside the detector acceptance.
Date: May 21, 2007
Creator: Vogt, R
Object Type: Article
System: The UNT Digital Library
APPLICATION OF POLYURETHANE FOAM FOR IMPACT ABSORPTION AND THERMAL INSULATION FOR RADIOACTIVE MATERIALS PACKAGINGS. (open access)

APPLICATION OF POLYURETHANE FOAM FOR IMPACT ABSORPTION AND THERMAL INSULATION FOR RADIOACTIVE MATERIALS PACKAGINGS.

Polyurethane foam has been widely used as an impact absorbing and thermal insulating material for large radioactive materials packages, since the 1980's. With the adoption of the regulatory crush test requirement, for smaller packages, polyurethane foam has been adopted as a replacement for cane fiberboard, because of its ability to withstand the crush test. Polyurethane foam is an engineered material whose composition is much more closely controlled than that of cane fiberboard. In addition, the properties of the foam can be controlled by controlling the density of the foam. The conditions under which the foam is formed, whether confined or unconfined have an affect on foam properties. The study reported here reviewed the application of polyurethane foam in RAM packagings and compared property values reported in the literature with published property values and test results for foam specimens taken from a prototype 9977 packaging. The study confirmed that, polyurethane foam behaves in a predictable and consistent manner and fully satisfies the functional requirements for impact absorption and thermal insulation.
Date: May 15, 2007
Creator: Smith, A; Glenn Abramczyk, G; Paul Blanton, P; Steve Bellamy, S; William Daugherty, W & Sharon Williamson, S
Object Type: Article
System: The UNT Digital Library