Resource Type

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Fast MAP Search for Compact Additive Tree Ensembles (CATE) (open access)

Fast MAP Search for Compact Additive Tree Ensembles (CATE)

None
Date: March 21, 2013
Creator: Prenger, R J; Chen, B Y; Marlatt, T L & Merl, D M
System: The UNT Digital Library
Final Scientific/Technical Report "Arc Tube Coating System for Color Consistency" (open access)

Final Scientific/Technical Report "Arc Tube Coating System for Color Consistency"

DOE has enabled the use of coating materials using low cost application methods on light sources to positively affect the output of those sources. The coatings and light source combinations have shown increased lumen output of LED fixtures (1.5%-2.0%), LED arrays (1.4%) and LED powered remote phosphor systems – Philips L-Prize lamp (0.9%). We have also demonstrated lifetime enhancements (3000 hrs vs 8000 hrs) and shifting to higher CRI (51 to 65) in metal halide high intensity discharge lamps with metal oxide coatings. The coatings on LEDs and LED products are significant as the market is moving increasingly more towards LED technology. Enhancements in LED performance are demonstrated in this work through the use of available materials and low cost application processes. EFOI used low refractive index fluoropolymers and low cost dipping processes for application of the material to surfaces related to light transmission of LEDs and LED products. Materials included Teflon AF, an amorphous fluorinated polymer and fluorinated acrylic monomers. The DOE SSL Roadmap sets goals for LED performance moving into the future. EFOI’s coating technology is a means to shift the performance curve for LEDs. This is not limited to one type of LED, but is relevant across …
Date: March 21, 2013
Creator: Buelow, Roger; Jenson, Chris & Kazenski, Keith
System: The UNT Digital Library
Hanford Site Rare Plant Monitoring Report for Calendar Year 2012 (open access)

Hanford Site Rare Plant Monitoring Report for Calendar Year 2012

Two patches of Columbian yellowcress on the Hanford Reach were visited in both 2011 and 2012 to compare ramet counts between years: near Allerd Pumphouse (Rkm 615.4) and near White Bluffs Boat Launch (Rkm 593.3) (Figure 3). In 2012, the population near Allerd Pumphouse had 45 ramets present within a 5x3 m area. At the same population in 2011, there were 60 ramets. In 2012, the population near White Bluffs Boat Launch had 105 ramets in a 2x2 m area. At the same population in 2011, there were 100 ramets. This data shows that while annual variability does exist, ramet counts were relatively similar from 2011 to 2012. This is likely due to the similar flow regimes of 2011 and 2012, which both had above average snowpack, high flows, and extended spring flooding seasons. A total of 19.6 miles (31.5 km) of the Hanford shoreline were surveyed in 2012, with ten patches identified and approximately 1,250 ramets counted. It is not known how many individual plants this count represents due to the rhizomatous nature of the species. Two of these sites were identified previously in the WNHP database, and the remaining eight were newly identified locations. Eleven of the ramets …
Date: March 21, 2013
Creator: Salstrom, D; Easterly, R; Lindsey, Cole T. & Nugent, John J.
System: The UNT Digital Library
Preparation and initial characterization of fluidized bed steam reforming pure-phase standards (open access)

Preparation and initial characterization of fluidized bed steam reforming pure-phase standards

Hanford is investigating the Fluidized Bed Steam Reforming (FBSR) process for their Low Activity Waste. The FBSR process offers a low-temperature continuous method by which liquid waste can be processed with the addition of clay into a sodium aluminosilicate (NAS) waste form. The NAS waste form is mainly comprised of nepheline (NaAlSiO{sub 4}), sodalite (Na{sub 8}[AlSiO{sub 4}]{sub 6}Cl{sub 2}), and nosean (Na{sub 8}[AlSiO{sub 4}]{sub 6}SO{sub 4}). Anions such as perrhenate (ReO{sub 4}{sup -}), pertechnetate (TcO{sub 4}{sup -}), and iodine (I{sup -}) are expected to replace sulfate in the nosean structure and/or chloride in the sodalite mineral structure (atomically bonded inside the aluminosilicate cages that these mineral structures possess). In the FBSR waste form, each of these phases can exist in a variety of solid solutions that differ from the idealized forms observed in single crystals in nature. The lack of understanding of the durability of these stoichiometric or idealized mineral phases complicates the ability to deconvolute the durability of the mixed phase FBSR product since it is a combination of different NAS phases. To better understand the behavior, fabrication and testing of the individual phases of the FBSR product is required. Analytical Development (AD) of the Science and Technology directorate …
Date: March 21, 2013
Creator: Missimer, D. M. & Rutherford, R. L.
System: The UNT Digital Library
Rayleigh-Taylor Instability within Sediment Layers Due to Gas Retention: Preliminary Theory and Experiments (open access)

Rayleigh-Taylor Instability within Sediment Layers Due to Gas Retention: Preliminary Theory and Experiments

In Hanford underground waste storage tanks, a typical waste configuration is settled beds of waste particles beneath liquid layers. The settled beds are typically composed of layers, and these layers can have different physical and chemical properties. One postulated configuration within the settled bed is a less-dense layer beneath a more-dense layer. The different densities can be a result of different gas retention in the layers or different degrees of settling and compaction in the layers. This configuration can experience a Rayleigh-Taylor (RT) instability where the less dense lower layer rises into the upper layer. Previous studies of gas retention and release have not considered potential buoyant motion within a settle bed of solids. The purpose of this report is to provide a review of RT instabilities, discuss predictions of RT behavior for sediment layers, and summarize preliminary experimental observations of RT instabilities in simulant experiments.
Date: March 21, 2013
Creator: Gauglitz, Phillip A.; Wells, Beric E.; Buchmiller, William C. & Rassat, Scot D.
System: The UNT Digital Library
RHIC orbit response analysis with LOCO Run 12 (open access)

RHIC orbit response analysis with LOCO Run 12

N/A
Date: March 21, 2013
Creator: T., Summers & Kewisch, J.
System: The UNT Digital Library
An Equivalent Circuit Model and Power Calculations for the APS SPX Crab Cavities. (open access)

An Equivalent Circuit Model and Power Calculations for the APS SPX Crab Cavities.

An equivalent parallel resistor-inductor-capacitor (RLC) circuit with beam loading for a polarized TM110 dipole-mode cavity is developed and minimum radio-frequency (rf) generator requirements are calculated for the Advanced Photon Source (APS) short-pulse x-ray (SPX) superconducting rf (SRF) crab cavities. A beam-loaded circuit model for polarized TM110 mode crab cavities was derived. The single-cavity minimum steady-state required generator power has been determined for the APS SPX crab cavities for a storage ring current of 200mA DC current as a function of external Q for various vertical offsets including beam tilt and uncontrollable detuning. Calculations to aid machine protection considerations were given.
Date: March 21, 2012
Creator: Berenc, T.
System: The UNT Digital Library
Molecular-Level Design of Heterogeneous Chiral Catalysis (open access)

Molecular-Level Design of Heterogeneous Chiral Catalysis

The following is a proposal to continue our multi-institutional research on heterogeneous chiral catalysis. Our team combines the use of surface-sensitive analytical techniques for the characterization of model systems with quantum and statistical mechanical calculations to interpret experimental data and guide the design of future research. Our investigation focuses on the interrelation among the three main mechanisms by which enantioselectivity can be bestowed to heterogeneous catalysts, namely: (1) by templating chirality via the adsorption of chiral supramolecular assemblies, (2) by using chiral modifiers capable of forming chiral complexes with the reactant and force enantioselective surface reactions, and (3) by forming naturally chiral surfaces using imprinting chiral agents. Individually, the members of our team are leaders in these various aspects of chiral catalysis, but the present program provides the vehicle to generate and exploit the synergies necessary to address the problem in a comprehensive manner. Our initial work has advanced the methodology needed for these studies, including an enantioselective titration procedure to identify surface chiral sites, infrared spectroscopy in situ at the interface between gases or liquids and solids to mimic realistic catalytic conditions, and DFT and Monte Carlo algorithms to simulate and understand chirality on surfaces. The next step, to …
Date: March 21, 2012
Creator: Zaera, Francisco
System: The UNT Digital Library
Newberry Seismic Deployment Fieldwork Report (open access)

Newberry Seismic Deployment Fieldwork Report

This report summarizes the seismic deployment of Lawrence Livermore National Laboratory (LLNL) Geotech GS-13 short-period seismometers at the Newberry Enhanced Geothermal System (EGS) Demonstration site located in Central Oregon. This Department of Energy (DOE) demonstration project is managed by AltaRock Energy Inc. AltaRock Energy had previously deployed Geospace GS-11D geophones at the Newberry EGS Demonstration site, however the quality of the seismic data was somewhat low. The purpose of the LLNL deployment was to install more sensitive sensors which would record higher quality seismic data for use in future seismic studies, such as ambient noise correlation, matched field processing earthquake detection studies, and general EGS microearthquake studies. For the LLNL deployment, seven three-component seismic stations were installed around the proposed AltaRock Energy stimulation well. The LLNL seismic sensors were connected to AltaRock Energy Gueralp CMG-DM24 digitizers, which are powered by AltaRock Energy solar panels and batteries. The deployment took four days in two phases. In phase I, the sites were identified, a cavity approximately 3 feet deep was dug and a flat concrete pad oriented to true North was made for each site. In phase II, we installed three single component GS-13 seismometers at each site, quality controlled the data …
Date: March 21, 2012
Creator: Wang, J. & Templeton, D. C.
System: The UNT Digital Library
Annual Report of Groundwater Monitoring at Everest, Kansas, in 2010. (open access)

Annual Report of Groundwater Monitoring at Everest, Kansas, in 2010.

The Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) began its environmental investigations at Everest, Kansas, in 2000. The work at Everest is implemented on behalf of the CCC/USDA by Argonne National Laboratory, under the oversight of the Kansas Department of Health and Environment (KDHE). The results of the environmental investigations have been reported in detail (Argonne 2001, 2003, 2006a,b). The lateral extent of the carbon tetrachloride in groundwater over the years of investigation has been interpreted as shown in Figure 1.1 (2001-2002 data), Figure 1.2 (2006 data), Figure 1.3 (2008 data), and Figure 1.4 (2009 data). The pattern of groundwater flow and inferred contaminant migration has consistently been to the north-northwest from the former CCC/USDA facility toward the Nigh property, and then west-southwest from the Nigh property (e.g., Figure 1.5 [2008 data] and Figure 1.6 [2009 data]). Both the monitoring data for carbon tetrachloride and the low groundwater flow rates estimated for the Everest aquifer unit (Argonne 2003, 2006a,b, 2008) indicate slow contaminant migration. On the basis of the accumulated findings, in March 2009 the CCC/USDA developed a plan for annual monitoring of the groundwater and surface water. This current monitoring plan (Appendix A in the report …
Date: March 21, 2011
Creator: Lafreniere, L. M.
System: The UNT Digital Library
Density Gradient Stabilization of Electron Temperature Gradient Driven Turbulence in a Spherical Tokamak (open access)

Density Gradient Stabilization of Electron Temperature Gradient Driven Turbulence in a Spherical Tokamak

In this letter we report the first clear experimental observation of density gradient stabilization of electron temperature gradient driven turbulence in a fusion plasma. It is observed that longer wavelength modes, k⊥ρs ≤10, are most stabilized by density gradient, and the stabilization is accompanied by about a factor of two decrease in the plasma effective thermal diffusivity.
Date: March 21, 2011
Creator: Ren, Y.; Mazzucato, E.; Guttenfelder, W.; Bell, R. E.; Domier, C. W.; LeBlanc, B. P. et al.
System: The UNT Digital Library
The LIFE Laser Design in Context: A Comparison to the State-of-the-Art (open access)

The LIFE Laser Design in Context: A Comparison to the State-of-the-Art

The current point design for the LIFE laser leverages decades of solid-state laser development in order to achieve the performance and attributes required for inertial fusion energy. This document provides a brief comparison of the LIFE laser point design to other state-of-the-art solid-state lasers. Table I compares the attributes of the current LIFE laser point design to other systems. the state-of-the-art for single-shot performance at fusion-relevant beamline energies is exemplified by performance observed on the National Ignition Facility. The state-of-the-art for high average power is exemplified by the Northrup Grumman JHPSSL laser. Several items in Table I deal with the laser efficiency; a more detailed discussion of efficiency can be found in reference 5. The electrical-to-optical efficiency of the LIFE design exceeds that of reference 4 due to the availability of higher efficiency laser diode pumps (70% vs. {approx}50% used in reference 4). LIFE diode pumps are discussed in greater detail in reference 6. The 'beam steering' state of the art is represented by the deflection device that will be used in the LIFE laser, not a laser system. Inspection of Table I shows that most LIFE laser attributes have already been experimentally demonstrated. The two cases where the LIFE …
Date: March 21, 2011
Creator: Deri, R. J.; Bayramian, A. J. & Erlandson, A. C.
System: The UNT Digital Library
Target Allocation Methodology for China's Provinces: Energy Intensity in the 12th FIve-Year Plan (open access)

Target Allocation Methodology for China's Provinces: Energy Intensity in the 12th FIve-Year Plan

Experience with China's 20% energy intensity improvement target during the 11th Five-Year Plan (FYP) (2006-2010) has shown the challenges of rapidly setting targets and implementing measures to meet them. For the 12th FYP (2011-2015), there is an urgent need for a more scientific methodology to allocate targets among the provinces and to track physical and economic indicators of energy and carbon saving progress. This report provides a sectoral methodology for allocating a national energy intensity target - expressed as percent change in energy per unit gross domestic product (GDP) - among China's provinces in the 12th FYP. Drawing on international experience - especially the European Union (EU) Triptych approach for allocating Kyoto carbon targets among EU member states - the methodology here makes important modifications to the EU approach to address an energy intensity rather than a CO{sub 2} emissions target, and for the wider variation in provincial energy and economic structure in China. The methodology combines top-down national target projections and bottom-up provincial and sectoral projections of energy and GDP to determine target allocation of energy intensity targets. Total primary energy consumption is separated into three end-use sectors - industrial, residential, and other energy. Sectoral indicators are used to …
Date: March 21, 2011
Creator: Ohshita, Stephanie & Price, Lynn
System: The UNT Digital Library
FINAL REPORT: Coupling Sorption to Soil Weathering During Reactive Transport: Impacts of Mineral Transformation and Sorbent Aging on Contaminant Speciation and Mobility (open access)

FINAL REPORT: Coupling Sorption to Soil Weathering During Reactive Transport: Impacts of Mineral Transformation and Sorbent Aging on Contaminant Speciation and Mobility

The goal of our project is a predictive-mechanistic understanding of the coupling between mineral weathering and contaminant (Cs, Sr, I) fate in caustic waste-impacted sediments at the Hanford Site. Through bench-scale experiments, we have identified geochemical transformations that alter the mobility of priority pollutants (Cs, Sr, I) in subsurface environments characteristic of high-level radioactive waste (HLRW)-impacted DoE sites. Our studies are designed to model the unique chemistry of this subsurface contamination, to quantify rates of contaminant uptake and release, and to identify molecular mechanisms of time-dependent, irreversible sequestration of contaminants into the solid phase. Our approach is to link quantitative macroscopic measures of contaminant mobility and partitioning to the molecular-scale mechanisms that mediate them. We have found that the molecular mechanisms themselves change with time and system composition in response to the evolving chemistry of contaminant-solution-mineral interactions. Specifically, our results show that contaminant fate is closely coupled to the major silicate incongruent weathering reactions that occur when soil solids are contacted with aqueous solutions under conditions that are far from equilibrium. Neoformed precipitates - including carbonate, feldspathoid and zeolite phases, have been observed to sequester Cs and Sr under caustic waste conditions. In contrast, iodide is less effectively sequestered into …
Date: March 21, 2009
Creator: O'Day, Peggy A.; Chorover, Jon; Mueller, Karl; Steefel, Carl & Serne, R. Jeff
System: The UNT Digital Library
Observed Minimum Illuminance Threshold for Night Market Vendors in Kenya who use LED Lamps (open access)

Observed Minimum Illuminance Threshold for Night Market Vendors in Kenya who use LED Lamps

Creation of light for work, socializing, and general illumination is a fundamental application of technology around the world. For those who lack access to electricity, an emerging and diverse range of LED based lighting products hold promise for replacing and/or augmenting their current fuel-based lighting sources that are costly and dirty. Along with analysis of environmental factors, economic models for total cost-ofownership of LED lighting products are an important tool for studying the impacts of these products as they emerge in markets of developing countries. One important metric in those models is the minimum illuminance demanded by end-users for a given task before recharging the lamp or replacing batteries. It impacts the lighting service cost per unit time if charging is done with purchased electricity, batteries, or charging services. The concept is illustrated in figure 1: LED lighting products are generally brightest immediately after the battery is charged or replaced and the illuminance degrades as the battery is discharged. When a minimum threshold level of illuminance is reached, the operational time for the battery charge cycle is over. The cost to recharge depends on the method utilized; these include charging at a shop at a fixed price per charge, charging …
Date: March 21, 2009
Creator: Johnstone, Peter; Jacobson, Arne; Mills, Evan & Radecsky, Kristen
System: The UNT Digital Library
Testing of FMI's Coal Upgrading Process (open access)

Testing of FMI's Coal Upgrading Process

WRI and FMI have collaborated to develop and test a novel coal upgrading technology. Proprietary coal upgrading technology is a fluidized bed-based continuous process which allows high through-puts, reducing the coal processing costs. Processing is carried out under controlled oxidizing conditions at mild enough conditions that compared to other coal upgrading technologies; the produced water is not as difficult to treat. All the energy required for coal drying and upgrading is derived from the coal itself. Under the auspices of the Jointly Sponsored Research Program, Cooperative Agreement DE-FC26-98FT40323, a nominal 400 lbs/hour PDU was constructed and operated. Over the course of this project, several low-rank coals were successfully tested in the PDU. In all cases, a higher Btu, low moisture content, stable product was produced and subsequently analyzed. Stack emissions were monitored and produced water samples were analyzed. Product stability was established by performing moisture readsorption testing. Product pyrophobicity was demonstrated by instrumenting a coal pile.
Date: March 21, 2009
Creator: Sethi, Vijay
System: The UNT Digital Library
Biologically Enhanced Carbon Sequestration: Research Needs and Opportunities (open access)

Biologically Enhanced Carbon Sequestration: Research Needs and Opportunities

Fossil fuel combustion, deforestation, and biomass burning are the dominant contributors to increasing atmospheric carbon dioxide (CO{sub 2}) concentrations and global warming. Many approaches to mitigating CO{sub 2} emissions are being pursued, and among the most promising are terrestrial and geologic carbon sequestration. Recent advances in ecology and microbial biology offer promising new possibilities for enhancing terrestrial and geologic carbon sequestration. A workshop was held October 29, 2007, at Lawrence Berkeley National Laboratory (LBNL) on Biologically Enhanced Carbon Sequestration (BECS). The workshop participants (approximately 30 scientists from California, Illinois, Oregon, Montana, and New Mexico) developed a prioritized list of research needed to make progress in the development of biological enhancements to improve terrestrial and geologic carbon sequestration. The workshop participants also identified a number of areas of supporting science that are critical to making progress in the fundamental research areas. The purpose of this position paper is to summarize and elaborate upon the findings of the workshop. The paper considers terrestrial and geologic carbon sequestration separately. First, we present a summary in outline form of the research roadmaps for terrestrial and geologic BECS. This outline is elaborated upon in the narrative sections that follow. The narrative sections start with the …
Date: March 21, 2008
Creator: Oldenburg, Curtis; Oldenburg, Curtis M. & Torn, Margaret S.
System: The UNT Digital Library
First Quarter Hanford Seismic Report for Fiscal Year 2008 (open access)

First Quarter Hanford Seismic Report for Fiscal Year 2008

The Hanford Seismic Assessment Program (HSAP) provides an uninterrupted collection of high-quality raw and processed seismic data from the Hanford Seismic Network for the U.S. Department of Energy and its contractors. The Hanford Seismic Assessment Team locates and identifies sources of seismic activity and monitors changes in the historical pattern of seismic activity at the Hanford Site. The data are compiled, archived, and published for use by the Hanford Site for waste management, natural phenomena hazards assessments, and engineering design and construction. In addition, the seismic monitoring organization works with the Hanford Site Emergency Services Organization to provide assistance in the event of a significant earthquake on the Hanford Site. The Hanford Seismic Network and the Eastern Washington Regional Network consist of 41 individual sensor sites and 15 radio relay sites maintained by the Hanford Seismic Assessment Team. For the Hanford Seismic Network, forty-four local earthquakes were recorded during the first quarter of fiscal year 2008. A total of thirty-one micro earthquakes were recorded within the Rattlesnake Mountain swarm area at depths in the 5-8 km range, most likely within the pre-basalt sediments. The largest event recorded by the network during the first quarter (November 25, 2007 - magnitude 1.5 …
Date: March 21, 2008
Creator: Rohay, Alan C.; Sweeney, Mark D.; Hartshorn, Donald C.; Clayton, Ray E. & Devary, Joseph L.
System: The UNT Digital Library
Comments on Worldsheet Theories Dual to Free Large N Gauge Theories (open access)

Comments on Worldsheet Theories Dual to Free Large N Gauge Theories

We continue to investigate properties of the worldsheet conformal field theories (CFTs) which are conjectured to be dual to free large N gauge theories, using the mapping of Feynman diagrams to the worldsheet suggested in [1]. The modular invariance of these CFTs is shown to be built into the formalism. We show that correlation functions in these CFTs which are localized on subspaces of the moduli space may be interpreted as delta-function distributions, and that this can be consistent with a local worldsheet description given some constraints on the operator product expansion coefficients. We illustrate these features by a detailed analysis of a specific four-point function diagram. To reliably compute this correlator we use a novel perturbation scheme which involves an expansion in the large dimension of some operators.
Date: March 21, 2007
Creator: Aharony, Ofer; /Weizmann Inst. /Stanford U., ITP /SLAC; David, Justin R.; Gopakumar, Rajesh; Inst., /Harish-Chandra Res.; Komargodski, Zohar et al.
System: The UNT Digital Library
End-Of-Life Vehicle Recycling: State of the Art of Resource Recovery From Shredder Residue. (open access)

End-Of-Life Vehicle Recycling: State of the Art of Resource Recovery From Shredder Residue.

Each year, more than 50 million vehicles reach the end of their service life throughout the world. More than 95% of these vehicles enter a comprehensive recycling infrastructure that includes auto parts recyclers/dismantlers, remanufacturers, and material recyclers (shredders). Today, about 75% of automotive materials are profitably recycled via (1) parts reuse and parts and components remanufacturing and (2) ultimately by the scrap processing (shredding) industry. The process by which the scrap processors recover metal scrap from automobiles involves shredding the obsolete automobiles, along with other obsolete metal-containing products (such as white goods, industrial scrap, and demolition debris), and recovering the metals from the shredded material. The single largest source of recycled ferrous scrap for the iron and steel industry is obsolete automobiles. The non-metallic fraction that remains after the metals are recovered from the shredded materials (about 25% of the weight of the vehicle)--commonly called shredder residue--is disposed of in landfills. Over the past 10 to 15 years, a significant amount of research and development has been undertaken to enhance the recycle rate of end-of-life vehicles (ELVs), including enhancing dismantling techniques and improving remanufacturing operations. However, most of the effort has focused on developing technology to recover materials, such as …
Date: March 21, 2007
Creator: Jody, B. J.; Daniels, E. J. & Systems, Energy
System: The UNT Digital Library
The Moduli Space and M(Atrix) Theory of 9d N=1 Backgrounds of M/String Theory (open access)

The Moduli Space and M(Atrix) Theory of 9d N=1 Backgrounds of M/String Theory

We discuss the moduli space of nine dimensional N = 1 supersymmetric compactifications of M theory/string theory with reduced rank (rank 10 or rank 2), exhibiting how all the different theories (including M theory compactified on a Klein bottle and on a Moebius strip, the Dabholkar-Park background, CHL strings and asymmetric orbifolds of type II strings on a circle) fit together, and what are the weakly coupled descriptions in different regions of the moduli space. We argue that there are two disconnected components in the moduli space of theories with rank 2. We analyze in detail the limits of the M theory compactifications on a Klein bottle and on a Moebius strip which naively give type IIA string theory with an uncharged orientifold 8-plane carrying discrete RR flux. In order to consistently describe these limits we conjecture that this orientifold non-perturbatively splits into a D8-brane and an orientifold plane of charge (-1) which sits at infinite coupling. We construct the M(atrix) theory for M theory on a Klein bottle (and the theories related to it), which is given by a 2 + 1 dimensional gauge theory with a varying gauge coupling compactified on a cylinder with specific boundary conditions. We …
Date: March 21, 2007
Creator: Aharony, Ofer; /Weizmann Inst. /Stanford U., ITP /SLAC; Komargodski, Zohar; Patir, Assaf & Inst., /Weizmann
System: The UNT Digital Library
Nanosecond Ultrasonics to Study Phase Transitions in Solid and Liquid Systems at High Pressure and Temperature (open access)

Nanosecond Ultrasonics to Study Phase Transitions in Solid and Liquid Systems at High Pressure and Temperature

This report describes the development of a high-frequency ultrasonic measurement capability for application to the study of phase transitions at elevated pressure and temperature. We combined expertise in various aspects of static high-pressure technique with recent advances in wave propagation modeling, ultrasonic transducer development, electronic methods and broadband instrumentation to accomplish the goals of this project. The transduction and electronic systems have a demonstrated bandwidth of 400 MHz, allowing investigations of phenomena with characteristic times as short as 2.5 nS. A compact, pneumatically driven moissanite anvil cell was developed and constructed for this project. This device generates a high-pressure environment for mm dimension samples to pressures of 3 GPa. Ultrasonic measurements were conducted in the moissanite cell, an LLNL multi-anvil device and in a modified piston cylinder device. Measurements for water, and elemental tantalum, tin and cerium demonstrate the success of the methods. The {gamma}-{alpha} phase transition in cerium was clearly detected at {approx}0.7 GPa with 75 MHz longitudinal waves. These results have direct application to important problems in LLNL programs, as well as seismology and planetary science.
Date: March 21, 2007
Creator: Bonner, B P; Berge, P A; Carlson, S C; Farber, D L & Akella, J
System: The UNT Digital Library
Preliminary Materials Selection Issues for the Next Generation Nuclear Plant Reactor Pressure Vessel. (open access)

Preliminary Materials Selection Issues for the Next Generation Nuclear Plant Reactor Pressure Vessel.

In the coming decades, the United States and the entire world will need energy supplies to meet the growing demands due to population increase and increase in consumption due to global industrialization. One of the reactor system concepts, the Very High Temperature Reactor (VHTR), with helium as the coolant, has been identified as uniquely suited for producing hydrogen without consumption of fossil fuels or the emission of greenhouse gases [Generation IV 2002]. The U.S. Department of Energy (DOE) has selected this system for the Next Generation Nuclear Plant (NGNP) Project, to demonstrate emissions-free nuclear-assisted electricity and hydrogen production within the next 15 years. The NGNP reference concepts are helium-cooled, graphite-moderated, thermal neutron spectrum reactors with a design goal outlet helium temperature of {approx}1000 C [MacDonald et al. 2004]. The reactor core could be either a prismatic graphite block type core or a pebble bed core. The use of molten salt coolant, especially for the transfer of heat to hydrogen production, is also being considered. The NGNP is expected to produce both electricity and hydrogen. The process heat for hydrogen production will be transferred to the hydrogen plant through an intermediate heat exchanger (IHX). The basic technology for the NGNP has …
Date: March 21, 2007
Creator: Natesan, K.; Majumdar, S.; Shankar, P. S. & Shah, V. N.
System: The UNT Digital Library
Remaining Sites Verification Package for the 1607-B2 Septic System and 100-B-14:2 Sanitary Sewer System, Waste Site Reclassification Form 2004-006 (open access)

Remaining Sites Verification Package for the 1607-B2 Septic System and 100-B-14:2 Sanitary Sewer System, Waste Site Reclassification Form 2004-006

The 100-B-14:2 subsite encompasses the former sanitary sewer feeder lines associated with the 1607-B2 and 1607-B7 septic systems. Feeder lines associated with the 185/190-B building have also been identified as the 100-B-14:8 subsite, and feeder lines associated with the 1607-B7 septic system have also been identified as the 100-B-14:9 subsite. These two subsites have been administratively cancelled to resolve the redundancy. The results of verification sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.
Date: March 21, 2007
Creator: Dittmer, L. M.
System: The UNT Digital Library