Electron Beam Lifetime in SPEAR3: Measurement and Simulation (open access)

Electron Beam Lifetime in SPEAR3: Measurement and Simulation

In this paper we report on electron beam lifetime measurements as a function of scraper position, RF voltage and bunch fill pattern in SPEAR3. We then outline development of an empirical, macroscopic model using the beam-loss rate equation. By identifying the dependence of loss coefficients on accelerator and beam parameters, a numerically-integrating simulator can be constructed to compute beam decay with time. In a companion paper, the simulator is used to train a parametric, non-linear dynamics model for the system [1].
Date: December 19, 2007
Creator: Corbett, J.; Huang, X.; Lee, M. & Lui, P.
Object Type: Article
System: The UNT Digital Library
Electron cyclotron resonance heating of tandem mirrors (open access)

Electron cyclotron resonance heating of tandem mirrors

Heating electrons by microwave power near either the electron cyclotron frequency or its harmonic is analyzed in some detail. The purpose of this study is to determine whether electrons in current or future mirror devices could be heated by electromagnetic waves in this frequency range. Absorption lengths, accessibility conditions, and appropriate polarization are among the concerns studied. It is found that the Tandem Mirror Experiment (TMX) may efficiently be heated by the extraordinary mode at omega = omega either in the solenoid-to-plug transition region or near the center of the plug at densities napprox. = 10/sup 13/cm/sup -3/.
Date: December 19, 1978
Creator: Porkolab, M.
Object Type: Report
System: The UNT Digital Library
Engineered Trench #3 Infiltration Estimates (open access)

Engineered Trench #3 Infiltration Estimates

This report documents the appropriate ET#3 infiltration rates to utilize as part of the ET#3 Special Analysis (SA).
Date: December 19, 2012
Creator: Phifer, M. A.
Object Type: Report
System: The UNT Digital Library
Enhancing the Atomic-Level Understanding of co2 Mineral Sequestration Mechanisms via Advanced Computational Modeling (open access)

Enhancing the Atomic-Level Understanding of co2 Mineral Sequestration Mechanisms via Advanced Computational Modeling

Fossil fuels currently provide 85% of the world's energy needs, with the majority coming from coal, due to its low cost, wide availability, and high energy content. The extensive use of coalfired power assumes that the resulting CO{sub 2} emissions can be vented to the atmosphere. However, exponentially increasing atmospheric CO{sub 2} levels have brought this assumption under critical review. Over the last decade, this discussion has evolved from whether exponentially increasing anthropogenic CO{sub 2} emissions will adversely affect the global environment, to the timing and magnitude of their impact. A variety of sequestration technologies are being explored to mitigate CO{sub 2} emissions. These technologies must be both environmentally benign and economically viable. Mineral carbonation is an attractive candidate technology as it disposes of CO{sub 2} as geologically stable, environmentally benign mineral carbonates, clearly satisfying the first criteria. The primary challenge for mineral carbonation is cost-competitive process development. CO{sub 2} mineral sequestration--the conversion of stationary-source CO{sub 2} emissions into mineral carbonates (e.g., magnesium and calcium carbonate, MgCO{sub 3} and CaCO{sub 3})--has recently emerged as one of the most promising sequestration options, providing permanent CO{sub 2} disposal, rather than storage. In this approach a magnesium-bearing feedstock mineral (typically serpentine or olivine; …
Date: December 19, 2002
Creator: Chizmeshya, A. V. G.
Object Type: Report
System: The UNT Digital Library
Enhancing the Atomic-Level Understanding of co2 Mineral Sequestration Mechanisms via Advanced Computational Modeling (open access)

Enhancing the Atomic-Level Understanding of co2 Mineral Sequestration Mechanisms via Advanced Computational Modeling

Fossil fuels currently provide 85% of the world's energy needs, with the majority coming from coal, due to its low cost, wide availability, and high energy content. The extensive use of coal-fired power assumes that the resulting CO{sub 2} emissions can be vented to the atmosphere. However, exponentially increasing atmospheric CO{sub 2} levels have brought this assumption under critical review. Over the last decade, this discussion has evolved from whether exponentially increasing anthropogenic CO{sub 2} emissions will adversely affect the global environment, to the timing and magnitude of their impact. A variety of sequestration technologies are being explored to mitigate CO{sub 2} emissions. These technologies must be both environmentally benign and economically viable. Mineral carbonation is an attractive candidate technology as it disposes of CO{sub 2} as geologically stable, environmentally benign mineral carbonates, clearly satisfying the first criteria. The primary challenge for mineral carbonation is cost-competitive process development. CO{sub 2} mineral sequestration--the conversion of stationary-source CO{sub 2} emissions into mineral carbonates (e.g., magnesium and calcium carbonate, MgCO{sub 3} and CaCO{sub 3})--has recently emerged as one of the most promising sequestration options, providing permanent CO{sub 2} disposal, rather than storage. In this approach a magnesium-bearing feedstock mineral (typically serpentine or olivine; …
Date: December 19, 2003
Creator: Chizmeshya, A. V. G.
Object Type: Report
System: The UNT Digital Library
Environmental Modeling Research at the University of North Carolina at Chapel Hill: Final Report (open access)

Environmental Modeling Research at the University of North Carolina at Chapel Hill: Final Report

Mechanistic mathematical models of environmental systems are used routinely to assess our understanding of the operative complex processes in nature. As our understanding matures, the complexity of these models increases and so too does the effort required to construct such models. This effort can be person years in some cases, and changes in model formulations or methods frequently leads to the need to either perform major revisions of existing codes or to abandon an existing code and recode the majority of the simulator. This project was intended to be a proof of concept approach aimed at developing a problem solving environment for the development of environmental models. The domain of focus was fluid flow and species transport in subsurface, porous medium systems. An approach was developed in which a mathematical model formulation was specified in LaTeX and this text document was processed, or compiled, multiple times to ultimately result in a computational simulator or model. The DOE developed Common Component Architecture paradigm was leveraged to implement solvers for reactions, integrators, algorithms, and discretization methods. A set of test problems was solved and the overall conclusion of the project is that a problem solving environment to support environmental modeling is certainly …
Date: December 19, 2006
Creator: Miller, C. T.
Object Type: Report
System: The UNT Digital Library
Estimation of Leak Rate from the Emergency Pump Well in L-Area Complex Basin (open access)

Estimation of Leak Rate from the Emergency Pump Well in L-Area Complex Basin

This report provides an estimate of the leak rate from the emergency pump well in L-basin that is to be expected during an off-normal event. This estimate is based on expected shrinkage of the engineered grout (i.e., controlled low strength material) used to fill the emergency pump well and the header pipes that provide the dominant leak path from the basin to the lower levels of the L-Area Complex. The estimate will be used to provide input into the operating safety basis to ensure that the water level in the basin will remain above a certain minimum level. The minimum basin water level is specified to ensure adequate shielding for personnel and maintain the ''as low as reasonably achievable'' concept of radiological exposure. The need for the leak rate estimation is the existence of a gap between the fill material and the header pipes, which penetrate the basin wall and would be the primary leak path in the event of a breach in those pipes. The gap between the pipe and fill material was estimated based on a full scale demonstration pour that was performed and examined. Leak tests were performed on full scale pipes as a part of this …
Date: December 19, 2005
Creator: Duncan, A
Object Type: Report
System: The UNT Digital Library
Evaluation of an eastern shale oil residue as an asphalt additive (open access)

Evaluation of an eastern shale oil residue as an asphalt additive

An evaluation of eastern shale oil (ESO) residue as an asphalt additive to reduce oxidative age-hardening and moisture susceptibility was conducted. The ESO residue, having a viscosity of 23.9 Pa{sm_bullet}s at 60{degrees}C (140{degrees}F), was blended with three different petroleum-derived asphalts, AAD-1, AAK-1, and AAM-1, that are known to be very susceptible to oxidative aging. Rheological and infrared analyses of the unaged and aged asphalts and the blends were then conducted to evaluate oxidative age-hardening. In addition, the petroleum-derived asphalts and the blends were coated onto three different aggregates, Lithonia granite (RA), a low-absorption limestone (RD), and a silicious Gulf Coast gravel (RL), and compacted into briquets. Successive freeze-thaw cycling was then conducted to evaluate the moisture susceptibility of the prepared briquets. The abbreviations used above for the asphalts and the aggregates are part of the Strategic Highway Research Program nomenclature.
Date: December 19, 1995
Creator: Thomas, K. P. & Harnsberger, P. M.
Object Type: Report
System: The UNT Digital Library
Evaluation of bisphenol E cyanate ester for the resin-injection repair of advanced composites (open access)

Evaluation of bisphenol E cyanate ester for the resin-injection repair of advanced composites

This thesis is a compilation of a general introduction and literature review that ties together the subsequent chapters which consist of two journal articles that have yet to be submitted for publication. The overall topic relates to the evaluation and application of a new class of cyanate ester resin with unique properties that lend it applicable to use as a resin for injection repair of high glass transition temperature polymer matrix composites. The first article (Chapter 2) details the evaluation and optimization of adhesive properties of this cyanate ester and alumina nanocomposites under different conditions. The second article (Chapter 3) describes the development and evaluation of an injection repair system for repairing delaminations in polymer matrix composites.
Date: December 19, 2009
Creator: Lio, Wilber Yaote
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Evaluation of selected chemical processes for production of low-cost silicon. Phase III. Twentieth quarterly progress report, July 1-September 30, 1980 (open access)

Evaluation of selected chemical processes for production of low-cost silicon. Phase III. Twentieth quarterly progress report, July 1-September 30, 1980

A number of problems have conspired to prevent full operation of the PDU during the report period. After a review of the situation, it was decided to cease the day-by-day attempts to achieve PDU operation, and to review the situation and make such longer-term repairs or modifications as appeared necessary for increasing the probability of success. As a result, a list of 12 modifications was made and the modifications initiated so that PDU operation can be initiated early in the next quarter. Analysis of the data on the outgassing of zinc from the product of the miniplant was concluded, with the indication that outgassing times of the order of tens of hours would be required at 1100 C. The implications of leaving the zinc in the product, to be evolved in melting prior to ingot or sheet growth, were examined with the conclusion that at the 10-100 ppmw level of zinc in silicon, it may be difficult to detect the zinc evolution in the presence of the normal SiO evolution caused by reaction between the liquid silicon and the fused-quartz crucible.
Date: December 19, 1980
Creator: Blocher, J.M. Jr.; Browning, M.F. & Seifert, D.A.
Object Type: Report
System: The UNT Digital Library
EXAMINATION OF Zr AND Ti RECOMBINER LOOP SPECIMENS (open access)

EXAMINATION OF Zr AND Ti RECOMBINER LOOP SPECIMENS

Cold-worked specimens of iodide zirconium, Zircaloy-2, iodide titanium, and A-55 titanium were tested in a high-pressure recombiner loop in an attempt to duplicate anomalous results obtained in a prior recombiner loop. Hydrogen analyses and metallographic examinations were made on all specimens. The titanium materials and Zircaloy-2 picked up major amounts of hydrogen in the cell section. None of the materials tested showed appreciable hydrogen absorption in the recombiner section. Complete recrystallization occurred in all cell specimens while only Zircaloy-2, of the recombiner specimens, showed any degree of recrystallization. No explanation for this behavior can be given. A survnnary of the data obtained in previous recombiner loops is compared with the results of this loop. Conclusions were based on the results of three recombiner loops. Primarlly because of the hydrogen absorption data obtained in all three recombiner loops it is recommended that the zirconium and titunium materials tested not be used in environments similar to those encountered in high pressure recombiner loops. (auth)
Date: December 19, 1958
Creator: Rittenhouse, P.L.
Object Type: Report
System: The UNT Digital Library
Experimental and Computational Study of Nonpremixed Ignition of Dimethyl Ether in Counterflow (open access)

Experimental and Computational Study of Nonpremixed Ignition of Dimethyl Ether in Counterflow

The ignition temperature of nitrogen-diluted dimethyl ether (DME) by heated air in counterflow was experimentally determined for DME concentration from 5.9 to 30%, system pressure from 1.5 to 3.0 atmospheres, and pressure-weighted strain rate from 110 to 170/s. These experimental data were compared with two mechanisms that were respectively available in 1998 and 2003, with the latter being a substantially updated version of the former. The comparison showed that while the 1998-mechanism uniformly over-predicted the ignition temperature, the 2003-mechanism yielded surprisingly close agreement for all experimental data. Sensitivity analysis for the near-ignition state based on both mechanisms identified the deficiencies of the 1998-mechanism, particularly the specifics of the low-temperature cool flame chemistry in effecting ignition at higher temperatures, as the fuel stream is being progressively heated from its cold boundary to the high-temperature ignition region around the hot-stream boundary. The 2003-mechanism, consisting of 79 species and 398 elementary reactions, was then systematically simplified by using the directed relation graph method to a skeletal mechanism of 49 species and 251 elementary reactions, which in turn was further simplified by using computational singular perturbation method and quasi-steady-state species assumption to a reduced mechanism consisting of 33 species and 28 lumped reactions. It …
Date: December 19, 2003
Creator: Zheng, X L; Lu, T F; Law, C K & Westbrook, C K
Object Type: Article
System: The UNT Digital Library
Experimental Criticality Benchmarks for SNAP 10A/2 Reactor Cores (open access)

Experimental Criticality Benchmarks for SNAP 10A/2 Reactor Cores

This report describes computational benchmark models for nuclear criticality derived from descriptions of the Systems for Nuclear Auxiliary Power (SNAP) Critical Assembly (SCA)-4B experimental criticality program conducted by Atomics International during the early 1960's. The selected experimental configurations consist of fueled SNAP 10A/2-type reactor cores subject to varied conditions of water immersion and reflection under experimental control to measure neutron multiplication. SNAP 10A/2-type reactor cores are compact volumes fueled and moderated with the hydride of highly enriched uranium-zirconium alloy. Specifications for the materials and geometry needed to describe a given experimental configuration for a model using MCNP5 are provided. The material and geometry specifications are adequate to permit user development of input for alternative nuclear safety codes, such as KENO. A total of 73 distinct experimental configurations are described.
Date: December 19, 2005
Creator: Krass, A.W.
Object Type: Report
System: The UNT Digital Library
Experimental investigation of the production of glueballs and meson resonance states (open access)

Experimental investigation of the production of glueballs and meson resonance states

We have made striking and considerable progress in our AGS program which is searching for a Quark-Gluon Plasma or other new phenomena at the AGS. We are employing a TCP Tracking Magnetic Spectrometer that has handled up to {approx}100 tracks, the maximum observed in 14.5 GeV/c {times} A Si ions incident on Au and Cu. In essence the TPC covers more than the forward half hemisphere in the nucleon-nucleon cms (i.e. {ge} 2{pi}) and thus allows tracking, momentum and angular analysis of the charged particles emitted in these heavy ion collisions. Particle identification for negative pions can be made approximately by assuming negative particles are pions. Then by subtraction of negatives from positives in a suitable manner the proton characteristics can be determined. {Lambda} and K{sub s}{sup 0} V particles have been identified singly in events and {approx}50 double {Lambda} and 2 triple {Lambda} events have been observed in the relatively small data sample we have obtained and analyzed this year. Further discussion of these topics are contained in this report.
Date: December 19, 1990
Creator: Lindenbaum, S. J.
Object Type: Report
System: The UNT Digital Library
EXPLOSIONS OCCURRING DURING CHEMICAL ETCHING OR PICKLING OF URANIUM- ZIRCONIUM ALLOYS (open access)

EXPLOSIONS OCCURRING DURING CHEMICAL ETCHING OR PICKLING OF URANIUM- ZIRCONIUM ALLOYS

None
Date: December 19, 1952
Creator: Roth, H.P.
Object Type: Report
System: The UNT Digital Library
Expression profiling and comparative sequence derived insights into lipid metabolism (open access)

Expression profiling and comparative sequence derived insights into lipid metabolism

Expression profiling and genomic DNA sequence comparisons are increasingly being applied to the identification and analysis of the genes involved in lipid metabolism. Not only has genome-wide expression profiling aided in the identification of novel genes involved in important processes in lipid metabolism such as sterol efflux, but the utilization of information from these studies has added to our understanding of the regulation of pathways participating in the process. Coupled with these gene expression studies, cross species comparison, searching for sequences conserved through evolution, has proven to be a powerful tool to identify important non-coding regulatory sequences as well as the discovery of novel genes relevant to lipid biology. An example of the value of this approach was the recent chance discovery of a new apolipoprotein gene (apo AV) that has dramatic effects upon triglyceride metabolism in mice and humans.
Date: December 19, 2001
Creator: Callow, Matthew J. & Rubin, Edward M.
Object Type: Article
System: The UNT Digital Library
Fabrication of Ceramic Layer-by-Layer Infrared Wavelength Photonic Band Gap Crystals (open access)

Fabrication of Ceramic Layer-by-Layer Infrared Wavelength Photonic Band Gap Crystals

Photonic band gap (PBG) crystals, also known as photonic crystals, are periodic dielectric structures which form a photonic band gap that prohibit the propagation of electromagnetic (EM) waves of certain frequencies at any incident angles. Photonic crystals have several potential applications including zero-threshold semiconductor lasers, the inhibition of spontaneous emission, dielectric mirrors, and wavelength filters. If defect states are introduced in the crystals, light can be guided from one location to another or even a sharp bending of light in micron scale can be achieved. This generates the potential for optical waveguide and optical circuits, which will contribute to the improvement in the fiber-optic communications and the development of high-speed computers.
Date: December 19, 2004
Creator: Kang, Henry Hao-Chuan
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Failure by fracture and fatigue in 'NANO' and 'BIO'materials (open access)

Failure by fracture and fatigue in 'NANO' and 'BIO'materials

The behavior of nanostructured materials/small-volumestructures and biologi-cal/bio-implantable materials, so-called "nano"and "bio" materials, is currently much in vogue in materials science. Oneaspect of this field, which to date has received only limited attention,is their fracture and fatigue properties. In this paper, we examine twotopics in this area, namely the premature fatigue failure ofsilicon-based micron-scale structures for microelectromechanical systems(MEMS), and the fracture properties of mineralized tissue, specificallyhuman bone.
Date: December 19, 2003
Creator: Ritchie, R. O.; Muhlstein, C. L. & Nalla, R. K.
Object Type: Article
System: The UNT Digital Library
Fatigue of welded 5083 aluminum alloy (open access)

Fatigue of welded 5083 aluminum alloy

A failure analysis was conducted on an aluminum (5083) structure subjected to fatigue testing. Failure occurred by fatigue in an electron-beam weld; the cycles to failure were reasonable for the loading conditions. (5 figures) (auth)
Date: December 19, 1973
Creator: Hanafee, J. E.
Object Type: Report
System: The UNT Digital Library
FEASIBILITY STUDY OF A NEW MASS FLOW SYSTEM. Quarterly Report No. 2 Covering the Period from September 1 to November 30, 1960 (open access)

FEASIBILITY STUDY OF A NEW MASS FLOW SYSTEM. Quarterly Report No. 2 Covering the Period from September 1 to November 30, 1960

Activities in a development program for a mass flow system capable of measuring homogeneous flow, slurries, highly corrosive fluids, and multiphase fluids are reported. The first experimental mass flow meter is nearly complete, and the required intensity of the radioactive source for mass measurements is being determined. Design of the vibrating reeds for the sources are completed. Absorption measurements at energies <100 kev indicate that composition effects are present, however, the effect is not considered serious since the system can be calibrated for each particular material. (J.R.D.)
Date: December 19, 1960
Creator: Burgwald, G.M.
Object Type: Report
System: The UNT Digital Library
FEDERAL USERS CONFERENCE PRODUCT LINE TOOL SET (PLTS) MAP PRODUCTION SYSTEM (MPS) ATLAS CUSTOM GRIDS [Rev 0 was draft] (open access)

FEDERAL USERS CONFERENCE PRODUCT LINE TOOL SET (PLTS) MAP PRODUCTION SYSTEM (MPS) ATLAS CUSTOM GRIDS [Rev 0 was draft]

Maps, and more importantly Atlases, are assisting the user community in managing a large land area with complex issues, the most complex of which is the management of nuclear waste. The techniques and experiences discussed herein were gained while developing several atlases for use at the US Department of Energy's Hanford Site. The user community requires the ability to locate not only waste sites, but other features as well. Finding a specific waste site on a map and in the field is a difficult task at a site the size of Hanford. To find a specific waste site, the user begins by locating the item or object in an index, then locating the feature on the corresponding map within an atlas. Locating features requires a method for indexing them. The location index and how to place it on a map or atlas is the central theme presented in this article. The user requirements for atlases forced the design team to develop new and innovative solutions for requirements that Product Line Tool Set (PLTS) Map Production System (MPS)-Atlas was not designed to handle. The layout of the most complex atlases includes custom reference grids, multiple data frames, multiple map series, and …
Date: December 19, 2006
Creator: Hayenga, J. L.
Object Type: Article
System: The UNT Digital Library
FINAL REPORT: Transformational electrode drying process (open access)

FINAL REPORT: Transformational electrode drying process

This report includes major findings and outlook from the transformational electrode drying project performance period from January 6, 2012 to August 1, 2012. Electrode drying before cell assembly is an operational bottleneck in battery manufacturing due to long drying times and batch processing. Water taken up during shipment and other manufacturing steps needs to be removed before final battery assembly. Conventional vacuum ovens are limited in drying speed due to a temperature threshold needed to avoid damaging polymer components in the composite electrode. Roll to roll operation and alternative treatments can increase the water desorption and removal rate without overheating and damaging other components in the composite electrode, thus considerably reducing drying time and energy use. The objective of this project was the development of an electrode drying procedure, and the demonstration of processes with no decrease in battery performance. The benchmark for all drying data was an 80°C vacuum furnace treatment with a residence time of 18 – 22 hours. This report demonstrates an alternative roll to roll drying process with a 500-fold improvement in drying time down to 2 minutes and consumption of only 30% of the energy compared to vacuum furnace treatment.
Date: December 19, 2013
Creator: Claus Daniel, C. & Wixom, M. (A123 Systems, Inc.)
Object Type: Report
System: The UNT Digital Library
Final Scientific Report DE-FGO3-97ER62460 Stomatal Responses to CO2: A Comparison of Woody and Herbaceous Species in Arid and Humid Climates (open access)

Final Scientific Report DE-FGO3-97ER62460 Stomatal Responses to CO2: A Comparison of Woody and Herbaceous Species in Arid and Humid Climates

OAK-B135 The project involved a study of a fundamental response of terrestrial vegetation to rising atmospheric carbon dioxide (CO2) concentration, namely, the change in leaf conductance to gas diffusion associated with a change in the aperture of the microscopic pores (stomata) on the surface of leaves.
Date: December 19, 2003
Creator: Koch, George W.
Object Type: Report
System: The UNT Digital Library
Finite Element Analysis Enhancement or B-25 Container Dynamic Compaction (open access)

Finite Element Analysis Enhancement or B-25 Container Dynamic Compaction

The document describes initial structural finite element modeling for dynamic compaction of B-25 containers buried in Engineered Trench number 1 at the U.S. Department of Energy's Savannah River Site (SRS), Aiken, South Carolina. Dynamic compaction is the practice of dropping a heavy weight to compact material that has been placed in the subsurface for disposal. B-25s placed in Engineered Trench number 1 contain low-level radioactive waste. Dynamic compaction of buried B-25s is an option that could mitigate subsidence of the cap that is eventually constructed over an engineered trench disposal site. The objective of numerical modeling of the Engineered trench system was to evaluate the response of B-25 Containers to dynamic compaction, eventually incorporating dynamic compaction behavior with various degrees of B-25 corrosion. Understanding the structural behavior of buried B-25s over time is important for anticipating and dealing with subsidence. Subsidence may compromise the long-term integrity of the caps placed over the buried waste to limit downward water and contaminant movement through the material.
Date: December 19, 2002
Creator: Jones, W. E.
Object Type: Report
System: The UNT Digital Library