University Reactor Sharing Program (open access)

University Reactor Sharing Program

Research projects supported by the program include items such as dating geological material and producing high current super conducting magnets. The funding continues to give small colleges and universities the valuable opportunity to use the NSC for teaching courses in nuclear processes; specifically neutron activation analysis and gamma spectroscopy. The Reactor Sharing Program has supported the construction of a Fast Neutron Flux Irradiator for users at New Mexico Institute of Mining and Technology and the University of Houston. This device has been characterized and has been found to have near optimum neutron fluxes for A39/Ar 40 dating. Institution final reports and publications resulting from the use of these funds are on file at the Nuclear Science Center.
Date: February 24, 2004
Creator: Reese, W. D.
Object Type: Report
System: The UNT Digital Library
Benchmarking optimization software with COPS 3.0. (open access)

Benchmarking optimization software with COPS 3.0.

The authors describe version 3.0 of the COPS set of nonlinearly constrained optimization problems. They have added new problems, as well as streamlined and improved most of the problems. They also provide a comparison of the FILTER, KNITRO, LOQO, MINOS, and SNOPT solvers on these problems.
Date: May 24, 2004
Creator: Dolan, E. D.; More, J. J. & Munson, T. S.
Object Type: Report
System: The UNT Digital Library
Dihadron correlations at high pT (open access)

Dihadron correlations at high pT

Jet quenching in the matter created in high energy nucleus/nucleus collisions provides a tomographic tool to probe the medium properties. Recent experimental results from the Relativistic Heavy-Ion Collider (RHIC) on characterization of jet production via dihadron correlations at high transverse momentum are reviewed. Expectations from the dihadron measurements for the lower energy {radical}s{sub NN} = 62.4 GeV RHIC run are discussed.
Date: July 24, 2004
Creator: Filimonov, Kirill
Object Type: Article
System: The UNT Digital Library
New physics searches with photons in CDF (open access)

New physics searches with photons in CDF

A brief review of searches for physics beyond the Standard Model with photons using the CDF detector at the Tevatron is given here. These include searches for supersymmetry, extra dimensions, excited electrons and W/Z+{gamma} production, as well as anomalous photon production. Recent results from CDF Run II experiment are presented, but some results from Run I are also reviewed.
Date: May 24, 2004
Creator: Lee, Sungwon
Object Type: Article
System: The UNT Digital Library
HB-Line Special Nuclear Material Campaigns: Model-Based Project Management (open access)

HB-Line Special Nuclear Material Campaigns: Model-Based Project Management

This study is to show how a model was used to enable management to better estimate production capabilities to ensure contract milestones/commitments are met, to cope with fast changing project baselines and project missions, to ensure the project will meet the negotiated throughput, and to eliminate unnecessary but costly design changes.
Date: March 24, 2004
Creator: Chang, Robert
Object Type: Article
System: The UNT Digital Library
Methane hydrate formation and dissociation in a partially saturated sand (open access)

Methane hydrate formation and dissociation in a partially saturated sand

To predict the behavior of hydrate-bearing sediments and the economic extractability of natural gas from reservoirs containing gas hydrates, we need reservoir simulators that properly represent the processes that occur, as well as accurate parameters. Several codes are available that represent some or all of the expected processes, and values for some parameters are available. Where values are unavailable, modelers have used estimation techniques to help with their predictions. Although some of these techniques are well respected, measurements are needed in many cases to verify the parameters. We have performed a series of experiments in a partially water saturated silica sand sample. The series included methane hydrate formation, and dissociation by both thermal stimulation and depressurization. The sample was 7.6 cm in diameter and 25 cm in length. In addition to measuring the system pressure and temperatures at four locations in the sample, we measured local density within the sample using x-ray computed tomography. Our goals in performing the experiment were to gather information for estimating thermal properties of the medium and to examine nonequilibrium processes.
Date: November 24, 2004
Creator: Kneafsey, Timothy J.; Tomutsa, Liviu; Taylor, Charles E.; Gupta, Arvind; Moridis, George; Freifeld, Barry et al.
Object Type: Article
System: The UNT Digital Library
Analytical Method for Measuring Total Protium and Total Deuterium in a Gas Mixture Containing H2, D2, and HD Via Gas Chromatography (open access)

Analytical Method for Measuring Total Protium and Total Deuterium in a Gas Mixture Containing H2, D2, and HD Via Gas Chromatography

A new analytical technique has been developed that measures both total protium (H) and deuterium (D) in a gas mixture containing H2, D2, and HD. This new analytical technique uses a micro gas chromatograph (GC) with two molecular sieve columns. One column uses D2 as the carrier gas and the other uses H2 as the carrier gas. Laboratory tests have shown that when used in this configuration the GC can measure both total protium and total deuterium, each with a sensitivity of less than 20 ppm. This new analytical technique was developed as a result of a request to provide instrumentation to measure the protium and deuterium concentrations at several process points during initial testing of the new hydrogen tritium thermal cycling absorption process columns.
Date: March 24, 2004
Creator: SESSIONS, HENRY
Object Type: Report
System: The UNT Digital Library
A New Method for In-situ Characterization of Important Actinides and Technetium Compounds via Fiberoptic Surface Enhanced Raman Spectroscopy (SERS) (open access)

A New Method for In-situ Characterization of Important Actinides and Technetium Compounds via Fiberoptic Surface Enhanced Raman Spectroscopy (SERS)

This project serves to fill information gap through the development of a novel surface-enhanced Raman scattering (SERS) spectroscopy to selectively and sensitively monitor and characterize the chemical speciation of radionuclides at trace levels. The SERS technique permits both of these measurements to be made simultaneously, and results in significant improvement over current methods in reducing time of analysis, cost, and sample manipulation. Our overall goal is (a) to develop a scientific basis for this new methodology to detect radionuclides via SERS and (b) to rationally synthesize and evaluate novel sol-gel based SERS substrates tailored to sensitively detect and characterize inorganic radionuclides such as TcO{sub 4}{sup -}, actinyl ions (e.g. UO{sub 2}{sup 2+}, NpO{sub 2}{sup +}, and PuO{sub 2}{sup 2+}) and other chemical compounds of interest.
Date: June 24, 2004
Creator: Dai, Sheng & Gu, B.
Object Type: Report
System: The UNT Digital Library
Investigation of Pore Scale Processes That Affect Soil Vapor Extraction (open access)

Investigation of Pore Scale Processes That Affect Soil Vapor Extraction

Dense nonaqueous phase liquid (DNAPL) contamination in the vadose zone is a significant problem at Department of Energy sites. Soil vapor extraction (SVE) is commonly used to remediate DNAPLs from the vadose zone. In most cases, a period of high recovery has been followed by a sustained period of low recovery. This behavior has been attributed to multiple processes including slow interphase mass transfer, retarded vapor phase transport, and diffusion from unswept zones of low permeability. Prior attempts to uncouple and quantify these processes have relied on column experiments, where the effluent concentration was monitored under different conditions in an effort to quantify the contributions from a single process. In real porous media these processes occur simultaneously and are inter-related. Further, the contribution from each of these processes varies at the pore scale and with time. This research aims to determine the pore-scale processes that limit the removal of DNAPL components in heterogeneous porous media during SVE. The specific objectives are to: (1) determine the effect of unswept zones on DNAPL removal during SVE, (2) determine the effect of retarded vapor phase transport on DNAPL removal during SVE, and (3) determine the effect of interphase mass transfer on DNAPL removal …
Date: June 24, 2004
Creator: Valocchi, Albert J.; Werth, Charles J. & Webb, Andrew G.
Object Type: Report
System: The UNT Digital Library
Fast-neutrons incident on gadolinium. (open access)

Fast-neutrons incident on gadolinium.

Reports in the Argonne National Laboratory Nuclear Data and Measurement Series present results of studies in the field of microscopic nuclear data. The primary objective of the series is the dissemination of information in the comprehensive form required for nuclear technology applications. This Series is devoted to: (a) measured microscopic nuclear parameters, (b) experimental techniques and facilities employed in measurements, (c) the analysis, correlation and interpretation of nuclear data, and (d) the compilation and evaluation of nuclear data. Contributions to this Series are reviewed to assure technical competence and, unless otherwise stated, the contents can be formally referenced. This Series does not supplant formal journal publication, but it does provide the more extensive information required for technological applications (e.g., tabulated numerical data) in a timely manner.
Date: May 24, 2004
Creator: Smith, A. B.
Object Type: Report
System: The UNT Digital Library
Axial Pressure Drop Measurements during Pilot-Scale Testing of a Mott Crossflow Filter (open access)

Axial Pressure Drop Measurements during Pilot-Scale Testing of a Mott Crossflow Filter

The Department of Energy selected CSSX as the preferred cesium removal technology for Savannah River Site waste. As a pretreatment step for the CSSX flowsheet, personnel contact the incoming salt solution that contains entrained sludge with MST to adsorb strontium and select actinides. They filter the resulting slurry to remove the sludge and MST. The filtrate receives further treatment to remove cesium in the solvent extraction system. The baseline filtration technology uses a Mott crossflow filter. We conducted pilot-scale crossflow filter testing with simulated SRS high level waste to evaluate the impact of operating parameters on the crossflow filtration process. The tests employed 0.5 micron and 0.1 micron filters. The feed slurries for these tests included simulated sludge plus MST, simulated sludge only, and simulated sludge plus manganese oxide solids. The supernate for these tests consisted of 5.6-6.4 M sodium, average salt solution. During the tests, we measured the axial pressure drop as a function of axial velocity, feed slurry, and insoluble solids concentration. This report documents the axial pressure drop data.
Date: June 24, 2004
Creator: POIRIER, MICHAEL
Object Type: Report
System: The UNT Digital Library
[Perovskite and Fluorite Grain Boundary Properties]. Final Project Report (open access)

[Perovskite and Fluorite Grain Boundary Properties]. Final Project Report

One of the main areas of research in the last two years in this program has been the properties of grain boundaries in perovskite and fluorite structure materials.
Date: February 24, 2004
Creator: Browning, N. D.
Object Type: Report
System: The UNT Digital Library
Topology of charge density and elastic properties of Ti3SiC2 polymorphs (open access)

Topology of charge density and elastic properties of Ti3SiC2 polymorphs

Using an all-electron, full potential first-principles method, we have investigated the topology of charge density and elastic properties of the two polymorphs, alpha and beta, of Ti3SiC2. The bonding effect was analyzed based on Bader's quantum theory of ''atoms in molecules'' (AIM). It was found that the Ti-Si bonding effect is significantly weaker in beta than in alpha, giving less stabilizing effect for beta. The Si-C bonds, which are absent in alpha, are formed in beta and provide additional stabilizing effect for beta. In contrast to conventional thinking, there is no direction interaction between Ti atoms in both alpha and beta. The calculated elastic properties are in good agreement with the experimental results, giving the bulk modulus of about 180 GPa and the Poisson's ratio of 0.2. The beta phase is generally softer than the alpha phase. As revealed by the direction dependent Young's modulus, there is only slight elastic anisotropy in Ti3SiC2. For alpha, Young's modulus is minimum in the c direction and maximum in the directions 42o from c. For beta, the maximum lies in the c direction, in part due to the formation of Si-C bonds in this direction.
Date: June 24, 2004
Creator: Yu, Rong; Zhang, Xiao Feng; He, Lian Long & Ye, Heng Qiang
Object Type: Article
System: The UNT Digital Library
Femtosecond nonlinear spectroscopy at surfaces: Second-harmonic probing of hole burning at the Si(111)7x7 surface and fourier-transform sum-frequency vibrational spectroscopy (open access)

Femtosecond nonlinear spectroscopy at surfaces: Second-harmonic probing of hole burning at the Si(111)7x7 surface and fourier-transform sum-frequency vibrational spectroscopy

The high temporal resolution and broad bandwidth of a femtosecond laser system are exploited in a pair of nonlinear optical studies of surfaces. The dephasing dynamics of resonances associated with the adatom dangling bonds of the Si(111)7 x 7 surface are explored by transient second-harmonic hole burning, a process that can be described as a fourth-order nonlinear optical process. Spectral holes produced by a 100 fs pump pulse at about 800 nm are probed by the second harmonic signal of a 100 fs pulse tunable around 800 nm. The measured spectral holes yield homogeneous dephasing times of a few tens of femtoseconds. Fits with a Lorentzian spectral hole centered at zero probe detuning show a linear dependence of the hole width on pump fluence, which suggests that charge carrier-carrier scattering dominates the dephasing dynamics at the measured excitation densities. Extrapolation of the deduced homogeneous dephasing times to zero excitation density yields an intrinsic dephasing time of {approx} 70 fs. The presence of a secondary spectral hole indicates that scattering of the surface electrons with surface optical phonons at 570 cm{sup -1} occurs within the first 200 fs after excitation. The broad bandwidth of femtosecond IR pulses is used to perform …
Date: November 24, 2004
Creator: McGuire, John Andrew
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Improved Miscible Nitrogen Flood Performance Utilizing Advanced Reservoir Characterization and Horizontal Laterals in a Class I Reservoir - East Binger (Marchand) Unit Quarterly Report (open access)

Improved Miscible Nitrogen Flood Performance Utilizing Advanced Reservoir Characterization and Horizontal Laterals in a Class I Reservoir - East Binger (Marchand) Unit Quarterly Report

Budget Period 2 of the East Binger Unit (''EBU'') DOE Project has been. Recent activities included additional data gathering and project monitoring, plus initiation of work on an SPE paper on the modeling efforts of the project. Early production performance suggests horizontal wells do not provide sufficient additional production over vertical wells to justify their incremental cost. It will take more time to evaluate the impact of the horizontal wells on sweep and ultimate recovery, but it is unlikely that an improvement in recovery will be sufficient to make the overall economic value of horizontal wells greater than the economic value of vertical wells. Monitoring of overall performance of the pilot area continues. Overall response to the various projects continues to be very favorable. Injection into the pilot area has nearly doubled, while gas production and nitrogen content of produced gas have both decreased. Nitrogen recycle within the pilot area has dropped from 60% to 20%. Efforts to further disseminate knowledge gained through this project, by means of technical paper presentations to industry groups, are underway. Project monitoring and technology transfer will be focus areas of Budget Period 3.
Date: August 24, 2004
Creator: Sinner, Joe
Object Type: Report
System: The UNT Digital Library
LCLS prototype undulator report. (open access)

LCLS prototype undulator report.

The Linac Coherent Light Source (LCLS) undulator line will consist of 33 undulator segments separated by breaks of two different lengths. The undulator segments are 3.4-m-long permanent-magnet planar hybrid devices with a period length of 30 mm and a magnetic gap of approximately 6 mm. Focusing quadrupoles, in a FODO lattice, and electron-beam diagnostics will be located in the breaks between undulator segments. Every third break will be longer in order to also accommodate x-ray diagnostics. Thus, taking the alternating focusing and defocusing quadrupoles into account, the ''super-period'' length before the undulator line repeats itself is six undulator segments. For additional details on the LCLS project and the undulator line, please refer to the conceptual design report (CDR). A full-length prototype undulator segment has been designed, manufactured and tested, and this document provides a comprehensive report of our experience with the prototype. It contains sections on the overall design philosophy and presents many important measurements including magnetic measurements of the magnet blocks, as well as of the assembled device, and mechanical and thermal measurements. It also contains a summary section (section 5) and one section that summarizes some remaining issues being investigated (section 6).
Date: February 24, 2004
Creator: Dejus, R.
Object Type: Report
System: The UNT Digital Library
Infrared Thermography in High Level Waste (open access)

Infrared Thermography in High Level Waste

The Savannah River Site is a Department of Energy, government-owned, company-operated industrial complex built in the 1950s to produce materials used in nuclear weapons. Five reactors were built to support the production of nuclear weapons material. Irradiated materials were moved from the reactors to one of the two chemical separation plants. In these facilities, known as ''canyons,'' the irradiated fuel and target assemblies were chemically processed to separate useful products from waste. Unfortunately, the by-product waste of nuclear material production was a highly radioactive liquid that had to be stored and maintained. In 1993 a strategy was developed to implement predictive maintenance technologies in the Liquid Waste Disposition Project Division responsible for processing the liquid waste. Responsibilities include the processing and treatment of 51 underground tanks designed to hold 750,000 to1,300,000 gallons of liquid waste and operation of a facility that vitrifies highly radioactive liquid waste into glass logs. Electrical and mechanical equipment monitored at these facilities is very similar to that found in non-nuclear industrial plants. Annual inspections are performed on electrical components, roof systems, and mechanical equipment. Troubleshooting and post installation and post-maintenance infrared inspections are performed as needed. In conclusion, regardless of the industry, the use of …
Date: August 24, 2004
Creator: GLEATON, DAVIDT.
Object Type: Article
System: The UNT Digital Library
The Development of an Innovative Vertical Floatation Melter and Scrap Dryer for Use in the Aluminum Processing Industry (open access)

The Development of an Innovative Vertical Floatation Melter and Scrap Dryer for Use in the Aluminum Processing Industry

The project aimed at the development of a Vertical Floatation melter, for application to the aluminum industry. This is intended to improve both the energy efficiency and environmental performance of aluminum melting furnaces. Phase I of this project dealt primarily with the initial research effort. Phase II, dealt with pilot-scale testing.
Date: August 24, 2004
Creator: Saro, Robert De
Object Type: Report
System: The UNT Digital Library
COAL PARTICLE FLOW PATTERNS FOR O{sub 2} ENRICHED, LOW NO{sub x} BURNERS (open access)

COAL PARTICLE FLOW PATTERNS FOR O{sub 2} ENRICHED, LOW NO{sub x} BURNERS

This year we focused on investigating the effect of particulate fines in both the hot flow and cold flow studies. This report summarizes the results of those studies in the hot flow and cold flow geometries. In the hot flow studies, increasing the fines content in the pulverized coal enhances combustion stability producing attached flames that were otherwise detached. NO{sub x} emissions are reduced by up to 50% through flame attachment. For always-attached flames, increasing the fraction of fines had little impact on total NO emissions. In the cold flow studies we found that the presence of the fine particles enhanced the velocity fluctuations of the coarse particles. The presence of coarse particles, however, did not affect the motion of the fine particles.
Date: April 24, 2004
Creator: Curtis, Jennifer Sinclair
Object Type: Report
System: The UNT Digital Library
Searches for physics beyond the standard model in ttbar events (open access)

Searches for physics beyond the standard model in ttbar events

The top quark is currently only observed at the Tevatron, where it is mainly produced in t{bar t} pairs. Due to the very high mass of the top quark compared to the other quarks and the gauge bosons, it is expected to play a special role in electroweak symmetry breaking. Therefore it might be especially sensitive to new physics. Measurements of various production and decay quantities of the top quark could lead to discoveries of physics beyond the standard model. Several such measurements were performed by the CDF collaboration during Run1 of the Tevatron. These measurements and first results from CDF in Run2 are presented.
Date: February 24, 2004
Creator: Merkel, P.
Object Type: Article
System: The UNT Digital Library
Optimizing the Delivery of Short-Lived Alpha Particle-Emitting Isotopes to Solid Tumors (open access)

Optimizing the Delivery of Short-Lived Alpha Particle-Emitting Isotopes to Solid Tumors

The underlying hypothesis of this project was that optimal alpha emitter-based radioimmunotherapy (RAIT) could be achieved by pairing the physical half-life of the radioisotope to the biological half-life of the targeting vehicle. The project had two specific aims. The first aim was to create and optimize the therapeutic efficacy of 211At-SAPS-C6.5 diabody conjugates. The second aim was to develop bispecific-targeting strategies that increase the specificity and efficacy of alpha-emitter-based RAIT. In the performance of the first aim, we created 211At-SAPS-C6.5 diabody conjugates that specifically targeted the HER2 tumor associated antigen. In evaluating these immunoconjugates we determined that they were capable of efficient tumor targeting and therapeutic efficacy of established human tumor xenografts growing in immunodeficient mice. We also determined that therapeutic doses were associated with late renal toxicity, likely due to the role of the kidneys in the systemic elimination o f these agents. We are currently performing more studies focused on better understanding the observed toxicity. In the second aim, we successfully generated bispecific single-chain Fv (bs-scFv) molecules that co-targeted HER2 and HER3 or HER2 and HER4. The in vitro kinetics and in vivo tumor-targeting properties of these molecules were evaluated. These studies revealed that the bs-scFv molecules selectively …
Date: November 24, 2004
Creator: Adams, Gregory P.
Object Type: Report
System: The UNT Digital Library
Electron Transport and Ion Acceleration in a Low-power Cylindrical Hall Thruster (open access)

Electron Transport and Ion Acceleration in a Low-power Cylindrical Hall Thruster

Conventional annular Hall thrusters become inefficient when scaled to low power. Cylindrical Hall thrusters, which have lower surface-to-volume ratio, are therefore more promising for scaling down. They presently exhibit performance comparable with conventional annular Hall thrusters. Electron cross-field transport in a 2.6 cm miniaturized cylindrical Hall thruster (100 W power level) has been studied through the analysis of experimental data and Monte Carlo simulations of electron dynamics in the thruster channel. The numerical model takes into account elastic and inelastic electron collisions with atoms, electron-wall collisions, including secondary electron emission, and Bohm diffusion. We show that in order to explain the observed discharge current, the electron anomalous collision frequency {nu}{sub B} has to be on the order of the Bohm value, {nu}{sub B} {approx} {omega}{sub c}/16. The contribution of electron-wall collisions to cross-field transport is found to be insignificant. The plasma density peak observed at the axis of the 2.6 cm cylindrical Hall thruster is likely to be due to the convergent flux of ions, which are born in the annular part of the channel and accelerated towards the thruster axis.
Date: June 24, 2004
Creator: Smirnov, A.; Raitses, Y. & Fisch, N.J.
Object Type: Report
System: The UNT Digital Library
Micron-gap ThermoPhotoVoltaics (MTPV) (open access)

Micron-gap ThermoPhotoVoltaics (MTPV)

This paper discusses advances made in the field of Micron-gap ThermoPhotoVoltaics (MTPV). Initial modeling has shown that MTPV may enable significant performance improvements relative to conventional far field TPV. These performance improvements include up to a 10x increase in power density, 30% to 35% fractional increase in conversion efficiency, or alternatively, reduced radiator temperature requirements to as low as 550 C. Recent experimental efforts aimed at supporting these predictions have successfully demonstrated that early current and voltage enhancements could be done repeatedly and at higher temperatures. More importantly, these efforts indicated that no unknown energy transfer process occurs reducing the potential utility of MTPV. Progress has been made by running tests with at least one of the following characteristics relative to the MTPV results reported in 2001: Tests at over twice the temperature (900 C); Tests at 50% smaller gaps (0.12 {micro}m); Tests with emitter areas from 4 to 100 times larger (16 mm{sup 2} to 4 cm{sup 2}); and Tests with over 20x reduction in parasitic spacer heat flow. Remaining fundamental challenges to realizing these improvements relative to the recent breakthroughs in conventional far field TPV include reengineering the photovoltaic (PV) diode, filter, and emitter system for MTPV and …
Date: August 24, 2004
Creator: DiMatteo, R.; Greiff, P.; Seltzer, D.; Meaulenberg, D.; Brown, E.; Carlen, E. et al.
Object Type: Article
System: The UNT Digital Library
Many small consumers, one growing problem: Achieving energy savings for electronic equipment operating in low power modes (open access)

Many small consumers, one growing problem: Achieving energy savings for electronic equipment operating in low power modes

An increasing amount of electricity is used by equipment that is neither fully ''on'' nor fully ''off.'' We call these equipment states low power modes, or ''lopomos.'' ''Standby'' and ''sleep'' are the most familiar lopomos, but some new products already have many modes. Lopomos are becoming common in household appliances, safety equipment, and miscellaneous products. Ross and Meier (2000) reports that several international studies have found standby power to be as much as 10 percent of residential energy consumption. Lopomo energy consumption is likely to continue growing rapidly as products with lopomos that use significant amounts of energy penetrate the market. Other sectors such as commercial buildings and industry also have lopomo energy use, perhaps totaling more in aggregate than that of households, but no comprehensive measurements have been made. In this paper, we propose a research agenda for study of lopomo energy consumption. This agenda has been developed with input from over 200 interested parties. Overall, there is consensus that lopomo energy consumption is an important area for research. Many see this as a critical time for addressing lopomo issues. As equipment designs move from the binary ''on/off'' paradigm to one that encompasses multiple power modes, there is a …
Date: August 24, 2004
Creator: Payne, Christopher T. & Meier, Alan K.
Object Type: Article
System: The UNT Digital Library