Adaptive 4-8 Texture Hierarchies (open access)

Adaptive 4-8 Texture Hierarchies

None
Date: April 14, 2004
Creator: Hwa, L M; Duchaineau, M A & Joy, K I
Object Type: Report
System: The UNT Digital Library
Carbon Nanotube-Based Permeable Membranes (open access)

Carbon Nanotube-Based Permeable Membranes

A membrane of multiwalled carbon nanotubes embedded in a silicon nitride matrix was fabricated for use in studying fluid mechanics on the nanometer scale. Characterization by fluorescent tracer diffusion and scanning electron microscopy suggests that the membrane is void-free near the silicon substrate on which it rests, implying that the hollow core of the nanotube is the only conduction path for molecular transport. Assuming Knudsen diffusion through this nanotube membrane, a maximum helium transport rate (for a pressure drop of 1 atm) of 0.25 cc/sec is predicted. Helium flow measurements of a nanoporous silicon nitride membrane, fabricated by sacrificial removal of carbon, give a flow rate greater than 1x10{sup -6} cc/sec. For viscous, laminar flow conditions, water is estimated to flow across the nanotube membrane (under a 1 atm pressure drop) at up to 2.8x10{sup -5} cc/sec (1.7 {micro}L/min).
Date: April 6, 2004
Creator: Holt, J K; Park, H G; Bakajin, O; Noy, A; Huser, T & Eaglesham, D
Object Type: Article
System: The UNT Digital Library
Preliminary Performance Measurements for a Streak Camera with a Large-Format Direct-Coupled CCD Readout (open access)

Preliminary Performance Measurements for a Streak Camera with a Large-Format Direct-Coupled CCD Readout

Livermore's ICF Program has a large inventory of optical streak cameras built in the 1970s and 1980s. The cameras are still very functional, but difficult to maintain because many of their parts are obsolete including the original streak tube and image-intensifier tube. The University of Rochester's Laboratory for Laser Energetics is leading an effort to develop a fully automated, large-format streak camera that incorporates modern technology. Preliminary characterization of a prototype camera shows spatial resolution better than 20 lp/mm, temporal resolution of 12 ps, line-spread function of 40 {micro}m (fwhm), contrast transfer ratio (CTR) of 60% at 10 lp/mm, and system sensitivity of 16 CCD electrons per photoelectron. A dynamic range of 60 for a 2 ns window is determined from system noise, linearity and sensitivity measurements.
Date: April 13, 2004
Creator: Lerche, R. A.; McDonald, J. W.; Griffith, R. L.; de Dios, G. V.; Andrews, D. S.; Huey, A. W. et al.
Object Type: Article
System: The UNT Digital Library
DENSITY-FUNCTIONAL CALCULATIONS FOR Ce, Th, AND Pu METALS AND ALLOYS (open access)

DENSITY-FUNCTIONAL CALCULATIONS FOR Ce, Th, AND Pu METALS AND ALLOYS

The phase diagrams of Ce, Th, and Pu metals have been studied by means of density-functional theory (DFT). In addition to these metals, the phase stability of Ce-Th and Pu-Am alloys has been also investigated from first-principles calculations. Equation-of-state (EOS) for Ce, Th, and the Ce-Th alloys has been calculated up to 1 Mbar pressure in good comparison to experimental data. Present calculations shows that the Ce-Th alloys adopt a body-centeredtetragonal (bct) structure upon hydrostatic compression that is in excellent agreement with measurements. The ambient pressure phase diagram of Pu is shown to be very poorly described by traditional DFT but rather well modeled when including magnetic interactions. In particular, the anomalous {var_sigma} phase of Pu is shown to be stabilized by magnetic disorder at elevated temperatures. The Pu-Am system has also been studied in a similar fashion and it is shown that this system, for about 25% Am content, becomes antiferromagnetic below about 400 K that corroborate the recent discovery of a Curie-Weiss behavior in this system.
Date: April 5, 2004
Creator: Landa, A & Soderlind, P
Object Type: Article
System: The UNT Digital Library
D-Zero HVAC Heat Pump Controls (open access)

D-Zero HVAC Heat Pump Controls

This engineering note documents the integration of Dzero Heat Pump 1 through Heat Pump 15 into the cryo/gas process control system commonly referred to as the cryo control system. Heat pumps 1 through 15 control the ambient air temperature on the 3rd, 5th, and 6th floor office areas at Dzero. The entire Johnson HVAC control system was replaced with a Siemens control system in 1999 leaving behind the 15 heat pumps with stand-alone Johnson controllers. Now, these 15 heat pump Johnson controllers are being replaced with small stand alone Beckhoff BC9000 controllers. The Beckhoff BC9000 controllers are network able into the existing Intellution control system. The Beckhoff BC9000 controllers use the cryo private Ethernet network and an OPC driver to get data into the Intellution SCADA node databases. The BC9000 is also programmed over this same Ethernet network.
Date: April 14, 2004
Creator: Markley, Dan
Object Type: Report
System: The UNT Digital Library
Electron Cloud Phase Transitions (open access)

Electron Cloud Phase Transitions

N/A
Date: April 1, 2004
Creator: U., Iriso & Peggs, S.
Object Type: Report
System: The UNT Digital Library
Final Phase II Report : QuickSite{reg_sign} investigation, Centralia, Kansas. (open access)

Final Phase II Report : QuickSite{reg_sign} investigation, Centralia, Kansas.

The Commodity Credit Corporation (CCC), an agency of the U.S. Department of Agriculture (USDA), formerly operated a grain storage facility approximately 1,100 ft north of Centralia from 1949 until 1971. Subsequently, a concrete mixing plant operated on the site (FSA 1997). None of the CCC/USDA structures remain, though belowgrade foundations related to structures associated with the concrete mixing operations are evident. Two additional grain storage facilities currently exist in and near Centralia: the Nemaha County Co-op, approximately 4,000 ft south of the former CCC/USDA facility, and a private grain storage facility near the Don Morris residence, 3,500 ft north of the former CCC/USDA facility (Figure 1.1). The property on which the former facility was located is currently owned by Jeanne Burdett Lacky of Seneca, Kansas. In August-September 1998 the Kansas Department of Health and Environment (KDHE) conducted preliminary investigations at the former CCC/USDA facility, on the basis of the detection of carbon tetrachloride in the domestic well at the Don Morris residence (north of the former CCC/USDA facility). Prior to 1986, commercial grain fumigants containing carbon tetrachloride were commonly used by the CCC/USDA and the grain storage industry to preserve grain. The details of previous investigations in the area and …
Date: April 1, 2004
Creator: LaFreniere, L. (Environmental Research)
Object Type: Report
System: The UNT Digital Library
A reformulation of intrabeam scattering theory (open access)

A reformulation of intrabeam scattering theory

N/A
Date: April 1, 2004
Creator: Parzen, G.
Object Type: Report
System: The UNT Digital Library
Probing the Planck Scale with Proton Decay (open access)

Probing the Planck Scale with Proton Decay

We advocate the idea that proton decay may probe physics at the Planck scale instead of the GUT scale. This is possible because supersymmetric theories have dimension-5 operators that can induce proton decay at dangerous rates, even with R-parity conservation. These operators are expected to be suppressed by the same physics that explains the fermion masses and mixings. We present a thorough analysis of nucleon partial lifetimes in models with a string-inspired anomalous U(1)_X family symmetry which is responsible for the fermionic mass spectrum as well as forbidding R-parity violating interactions. Protons and neutrons can decay via R-parity conserving non-renormalizable superpotential terms that are suppressed by the Planck scale and powers of the Cabibbo angle. Many of the models naturally lead to nucleon decay near present limits without any reference to grand unification.
Date: April 28, 2004
Creator: Harnik, Roni; Larson, Daniel T.; Murayama, Hitoshi & Thormeier, Marc
Object Type: Article
System: The UNT Digital Library
Results from ORNL Characterization of Archive German Particles (open access)

Results from ORNL Characterization of Archive German Particles

This document is a compilation of the characterization data obtained on a sample of TRISO-coated 500 {micro}m UO{sub 2} produced by the Germans and obtained by the AGR program for use as a reference material. This sample came from the EUO 2358-2365 composite studied by General Atomics (GA) and referenced in GA document No.910852 'Acceptance Test report for German Fuel Particles'. The ORNL designation for the material characterized was AGR-06.
Date: April 1, 2004
Creator: Hunn, John D
Object Type: Report
System: The UNT Digital Library
Precious Metal Recovery from Fuel Cell MEA's (open access)

Precious Metal Recovery from Fuel Cell MEA's

In 2003, Engelhard Corporation received a DOE award to develop a cost-effective, environmentally friendly approach to recover Pt from fuel cell membrane electrode assemblies (MEA’s). The most important precious metal used in fuel cells is platinum, but ruthenium is also added to the anode electrocatalyst if CO is present in the hydrogen stream. As part of the project, a large number of measurements of Pt and Ru need to be made. A low-cost approach to measuring Pt is using the industry standard spectrophotometric measurement of Pt complexed with stannous chloride. The interference of Ru can be eliminated by reading the Pt absorbance at 450 nm. Spectrophotometric methods for measuring Ru, while reported in the literature, are not as robust. This paper will discuss the options for measuring Pt and Ru using the method of UV-VIS spectrophotometry
Date: April 25, 2004
Creator: Shore, Lawrence
Object Type: Article
System: The UNT Digital Library
Supersymmetric Froggatt-Nielsen Models with Baryon- and Lepton-Number Violation (open access)

Supersymmetric Froggatt-Nielsen Models with Baryon- and Lepton-Number Violation

We systematically investigate the embedding of U(1)_X Froggatt-Nielsen models in (four-dimensional) local supersymmetry. We restrict ourselves to models with a single flavon field. We do not impose a discrete symmetry by hand, e.g., R-parity, baryon-parity or lepton-parity. Thus we determine the order of magnitude of the baryon- and/or lepton violating coupling constants through the Froggatt-Nielsen mechanism. We then scrutinize whether the predicted coupling constants are in accord with weak or GUT scale constraints. Many models turn out to be incompatible.
Date: April 16, 2004
Creator: Dreiner, Herbi K. & Thormeier, Marc
Object Type: Article
System: The UNT Digital Library
MOAB : a mesh-oriented database. (open access)

MOAB : a mesh-oriented database.

A finite element mesh is used to decompose a continuous domain into a discretized representation. The finite element method solves PDEs on this mesh by modeling complex functions as a set of simple basis functions with coefficients at mesh vertices and prescribed continuity between elements. The mesh is one of the fundamental types of data linking the various tools in the FEA process (mesh generation, analysis, visualization, etc.). Thus, the representation of mesh data and operations on those data play a very important role in FEA-based simulations. MOAB is a component for representing and evaluating mesh data. MOAB can store structured and unstructured mesh, consisting of elements in the finite element 'zoo'. The functional interface to MOAB is simple yet powerful, allowing the representation of many types of metadata commonly found on the mesh. MOAB is optimized for efficiency in space and time, based on access to mesh in chunks rather than through individual entities, while also versatile enough to support individual entity access. The MOAB data model consists of a mesh interface instance, mesh entities (vertices and elements), sets, and tags. Entities are addressed through handles rather than pointers, to allow the underlying representation of an entity to change …
Date: April 1, 2004
Creator: Tautges, Timothy James; Ernst, Corey; Stimpson, Clint; Meyers, Ray J. & Merkley, Karl
Object Type: Report
System: The UNT Digital Library
Implementation of Fisheries Enhancement Opportunities on the Coeur d'Alene Reservation; Coeur d'Alene Tribe Fish, Water, and Wildlife Program, REVISED 2002 Annual Report. (open access)

Implementation of Fisheries Enhancement Opportunities on the Coeur d'Alene Reservation; Coeur d'Alene Tribe Fish, Water, and Wildlife Program, REVISED 2002 Annual Report.

Historically, the Coeur d'Alene Indian Tribe depended on runs of anadromous salmon and steelhead along the Spokane River and Hangman Creek, as well as resident and adfluvial forms of trout and char in Coeur d'Alene Lake, for survival. Dams constructed in the early 1900s on the Spokane River in the City of Spokane and at Little Falls (further downstream) were the first dams that initially cut-off the anadromous fish runs from the Coeur d'Alene Tribe. These fisheries were further removed by the construction of Chief Joseph and Grand Coulee Dams on the Columbia River. Together, these actions forced the Tribe to rely solely on the resident fish resources of Coeur d'Alene Lake (Staff Communication). The Coeur d'Alene Tribe is estimated to have historically harvested around 42,000 westslope cutthroat trout (Oncorhynchus clarki) per year (Scholz et al. 1985). In 1967, Mallet (1969) reported that 3,329 cutthroat were harvested from the St. Joe River, and a catch of 887 was reported from Coeur d'Alene Lake. This catch is far less than the 42,000 fish per year the tribe harvested historically. Today, only limited opportunities exist to harvest cutthroat trout in the Coeur d'Alene Basin. The declines in native salmonid fish populations, particularly …
Date: April 1, 2004
Creator: Vitale, Angelo; Lamb, Dave & Scott, Jason
Object Type: Report
System: The UNT Digital Library
What can we learn from neutrinoless double beta decay experiments? (open access)

What can we learn from neutrinoless double beta decay experiments?

We assess how well next generation neutrinoless double beta decay and normal neutrino beta decay experiments can answer four fundamental questions. 1) If neutrinoless double beta decay searches do not detect a signal, and if the spectrum is known to be inverted hierarchy, can we conclude that neutrinos are Dirac particles? 2) If neutrinoless double beta decay searches are negative and a next generation ordinary beta decay experiment detects the neutrino mass scale, can we conclude that neutrinos are Dirac particles? 3) If neutrinoless double beta decay is observed with a large neutrino mass element, what is the total mass in neutrinos? 4) If neutrinoless double beta decay is observed but next generation beta decay searches for a neutrino mass only set a mass upper limit, can we establish whether the mass hierarchy is normal or inverted? We base our answers on the expected performance of next generation neutrinoless double beta decay experiments and on simulations of the accuracy of calculations of nuclear matrix elements.
Date: April 8, 2004
Creator: Bahcall, John N.; Murayama, Hitoshi & Pena-Garay, Carlos
Object Type: Article
System: The UNT Digital Library
Constraints and Superspin for SuperPoincare Algebras in Diverse Dimensions (open access)

Constraints and Superspin for SuperPoincare Algebras in Diverse Dimensions

We generalize to arbitrary dimension the construction of a covariant and supersymmetric constraint for the massless superPoincare algebra, which was given for the eleven-dimensional case in a previous work. We also contrast it with a similar construction appropriate to the massive case. Finally we show that the constraint uniquely fixes the representation of the algebra.
Date: April 27, 2004
Creator: Pasqua, Andrea & Zumino, Bruno
Object Type: Article
System: The UNT Digital Library
Little Supersymmetry and the Supersymmetric Little Hierarchy Problem (open access)

Little Supersymmetry and the Supersymmetric Little Hierarchy Problem

The current experimental lower bound on the Higgs mass significantly restricts the allowed parameter space in most realistic supersymmetric models, with the consequence that these models exhibit significant fine-tuning. We propose a solution to this `supersymmetric little hierarchy problem'. We consider scenarios where the stop masses are relatively heavy - in the 500 GeV to a TeV range. Radiative stability of the Higgs soft mass against quantum corrections from the top quark Yukawa coupling is achieved by imposing a global SU(3) symmetry on this interaction. This global symmetry is only approximate - it is not respected by the gauge interactions. A subgroup of the global symmetry is gauged by the familiar SU(2) of the Standard Model. The physical Higgs is significantly lighter than the other scalars because it is the pseudo-Goldstone boson associated with the breaking of this symmetry. Radiative corrections to the Higgs potential naturally lead to the right pattern of gauge and global symmetry breaking. We show that both the gauge and global symmetries can be embedded into a single SU(6) grand unifying group, thereby maintaining the prediction of gauge coupling unification. Among the firm predictions of this class of models are new states with the quantum numbers …
Date: April 22, 2004
Creator: Birkedal, Andreas; Chacko, Z. & Gaillard, Mary K.
Object Type: Article
System: The UNT Digital Library
Design of a 2 Slot VLPC Cryostat Cooled by a Cryocooler (open access)

Design of a 2 Slot VLPC Cryostat Cooled by a Cryocooler

The conceptual design and preliminary engineering calculations have been completed for a two cassette cryostat. This report summarizes the design. A cryocooler is permanently mounted in the center of a stainless steel, 0.75 inch thick top lid. The cryocooler sits upon a spacer which raises the cooling stage elevations to favorably match the cassette heat intercept elevations. The top lid (32.0-inch outside diameter) mates to a 24-inch pipe size flange with o-ring. The 24-inch pipe size vacuum vessel with end plate has a minimum internal depth of 16-inch to give adequate clearance for the depth of the cryocooler and multilayer insulation blankets. Support stand legs elevate the container to a convenient height and allow for placement of the AFE power supply underneath. Two cassette slots are located on either side of the cryocooler. The slots are positioned parallel to each other, 10.5-inch center to center (6 standard cassette slot widths) so that the standard 8 slot AFE backplane can be used. The slot opening through the lid is approximately 1.422-inch x 16.782-inch. A 0.016-inch thick titanium (Ti-6AI-4V) envelope with sealing lip is inserted through lid and defines the gas helium boundary that the VLPC cassette resides. The internal dimensions of …
Date: April 22, 2004
Creator: Rucinski, Russell A.
Object Type: Report
System: The UNT Digital Library

Virtual Institute of Microbial Stress and Survival: Deduction of Stress Response Pathways in Metal and Radionuclide Reducing Microorganisms

The projects application goals are to: (1) To understand bacterial stress-response to the unique stressors in metal/radionuclide contamination sites; (2) To turn this understanding into a quantitative, data-driven model for exploring policies for natural and biostimulatory bioremediation; (3) To implement proposed policies in the field and compare results to model predictions; and (4) Close the experimental/computation cycle by using discrepancies between models and predictions to drive new measurements and construction of new models. The projects science goals are to: (1) Compare physiological and molecular response of three target microorganisms to environmental perturbation; (2) Deduce the underlying regulatory pathways that control these responses through analysis of phenotype, functional genomic, and molecular interaction data; (3) Use differences in the cellular responses among the target organisms to understand niche specific adaptations of the stress and metal reduction pathways; (4) From this analysis derive an understanding of the mechanisms of pathway evolution in the environment; and (5) Ultimately, derive dynamical models for the control of these pathways to predict how natural stimulation can optimize growth and metal reduction efficiency at field sites.
Date: April 17, 2004
Creator: unknown
Object Type: Presentation
System: The UNT Digital Library
Power Systems Development Facility (open access)

Power Systems Development Facility

This report discusses Test Campaign TC15 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Power Generation, Inc. (SPG) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or gasifier using a particulate control device (PCD). While operating as a gasifier, either air or oxygen can be used as the oxidant. Test run TC15 began on April 19, 2004, with the startup of the main air compressor and the lighting of the gasifier startup burner. The Transport Gasifier was shutdown on April 29, 2004, accumulating 200 hours of operation using Powder River Basin (PRB) subbituminous coal. About 91 hours of the test run occurred during oxygen-blown operations. Another 6 hours of the test run was in enriched-air mode. The remainder of the test run, approximately 103 hours, took place during air-blown operations. The highest operating temperature in the gasifier mixing zone mostly varied from 1,800 to 1,850 F. The gasifier exit pressure ran between 200 and 230 psig during air-blown operations and between 110 and 150 psig in oxygen-enhanced air operations.
Date: April 30, 2004
Creator: Southern Company Services
Object Type: Text
System: The UNT Digital Library
Study of metal dusting phenomenon and development of materials resistant to metal dusting. Final report. (open access)

Study of metal dusting phenomenon and development of materials resistant to metal dusting. Final report.

None
Date: April 5, 2004
Creator: Natesan, K. & Zeng, Z.
Object Type: Report
System: The UNT Digital Library
Development of the Embedded Membrane Concept (open access)

Development of the Embedded Membrane Concept

Recent evaluations in the field of biomass separations have resulted in a novel concept termed the “embedded membrane.” Biomass solutions, which typically consist of a sludge-like material, contain a wide range of particle types and concentrations. These highly abusive solutions have the potential to cause reduced flux and even catastrophic failure through erosion mechanisms within the membrane. The embedded membrane concept relies on embedding finer, filtration inducing particles (e.g. ceramic such as TiO2) into the interstices of a macroporous support (e.g., sintered metal such as sintered stainless steel). It is believed that the embedded membrane would be resistant to erosion processes, since only the macroporous support material would be subjected to the harsh hydrodynamic properties of the flowing bulk process fluid. Moreover, the finer, filtration inducing embedded particles that provide the necessary filtration efficiency are protected from the bulk process fluid. In an effort to investigate the embedded membrane concept, samples of sintered stainless steel membranes embedded with ceramic particles have been prepared.
Date: April 1, 2004
Creator: Mann, Nick R.; Herbst, R. S. & Trowbridge, T. L.
Object Type: Article
System: The UNT Digital Library
New geothermal site identification and qualification. Final report (open access)

New geothermal site identification and qualification. Final report

This study identifies remaining undeveloped geothermal resources in California and western Nevada, and it estimates the development costs of each. It has relied on public-domain information and such additional data as geothermal developers have chosen to make available. Reserve estimation has been performed by volumetric analysis with a probabilistic approach to uncertain input parameters. Incremental geothermal reserves in the California/Nevada study area have a minimum value of 2,800 grosss MW and a most-likely value of 4,300 gross MW. For the state of California alone, these values are 2,000 and 3,000 gross MW, respectively. These estimates may be conservative to the extent that they do not take into account resources about which little or no public-domain information is available. The average capital cost of incremental generation capacity is estimated to average $3,100/kW for the California/Nevada study area, and $2,950/kW for the state of California alone. These cost estimates include exploration, confirmation drilling, development drilling, plant construction, and transmission-line costs. For the purposes of this study, a capital cost of $2,400/kW is considered competitive with other renewable resources. The amount of incremental geothermal capacity available at or below $2,400/kW is about 1,700 gross MW for the California/Nevada study area, and the same …
Date: April 1, 2004
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Corrective measures evaluation work plan Technical Area V groundwater. (open access)

Corrective measures evaluation work plan Technical Area V groundwater.

This document, which is prepared as directed by the Compliance Order on Consent (COOC) issued by the New Mexico Environment Department, identifies and outlines a process to evaluate remedial alternatives to identify a corrective measure for the Sandia National Laboratories New Mexico Technical Area (TA)-V Groundwater. The COOC provides guidance for implementation of a Corrective Measures Evaluation (CME) for the TA-V Groundwater. This Work Plan documents an initial screening of remedial technologies and presents a list of possible remedial alternatives for those technologies that passed the screening. This Work Plan outlines the methods for evaluating these remedial alternatives and describes possible site-specific evaluation activities necessary to estimate remedy effectiveness and cost. These methods will be reported in the CME Report. This Work Plan outlines the CME Report, including key components and a description of the corrective measures process.
Date: April 1, 2004
Creator: Lebow, Patrick S.; Dettmers, Dana L. & Hall, Kevin A.
Object Type: Report
System: The UNT Digital Library