EFFECT OF GLASS-BATCH MAKEUP ON THE MELTING PROCESS (open access)

EFFECT OF GLASS-BATCH MAKEUP ON THE MELTING PROCESS

The response of a glass batch to heating is determined by the batch makeup and in turn determines the rate of melting. Batches formulated for a high-alumina nuclear waste to be vitrified in an all-electric melter were heated at a constant temperature-increase rate to determine changes in melting behavior in response to the selection of batch chemicals and silica grain-size as well as the addition of heat-generating reactants. The type of batch materials and the size of silica grains determine how much, if any, primary foam occurs during melting. Small quartz grains, 5 {micro}m in size, caused extensive foaming because their major portion dissolved at temperatures <800 C, contributing to the formation of viscous glass forming melt that trapped evolving batch gases. Primary foam did not occur in batches with larger quartz grains, {+-}75 {micro}m in size, because their major portion dissolved at temperatures >800 C when batch gases no longer evolved. The exothermal reaction of nitrates with sucrose was ignited at a temperature as low as 160 C and caused a temporary jump in temperature of several hundred degrees. Secondary foam, the source of which is oxygen from redox reactions, occurred in all batches of a limited composition variation …
Date: December 7, 2010
Creator: AA, KRUGER & P, HRMA
Object Type: Article
System: The UNT Digital Library
Probing Ferroelectricity in PbZr0.2Ti0.8O3 with Polarized Soft X-rays (open access)

Probing Ferroelectricity in PbZr0.2Ti0.8O3 with Polarized Soft X-rays

The reduction in symmetry associated with the onset of ferroelectric order in PbZr{sub 0.2}Ti{sub 0.8}O{sub 3} (PZT) thin films leads to a pronounced difference at the Ti L{sub 3,2} absorption edges between spectra measured with the x-ray linear polarization perpendicular and parallel to the ferroelectric polarization. We introduce a general method to analyze the observed difference spectra using atomic multiplet calculations. Moreover, we find experimental evidence for structural changes in PZT induced by the reversal of the ferroelectric polarization.
Date: June 7, 2010
Creator: Arenholz, E.; van der Laan, G.; Fraile-Rodriguez, A.; Yu, P.; He, Q. & Ramesh, R.
Object Type: Article
System: The UNT Digital Library
MATERIAL TRACKING USING LANMAS (open access)

MATERIAL TRACKING USING LANMAS

LANMAS is a transaction-based nuclear material accountability software product developed to replace outdated and legacy accountability systems throughout the DOE. The core underlying purpose of LANMAS is to track nuclear materials inventory and report transactions (movement, mixing, splitting, decay, etc.) to the Nuclear Materials Management and Safeguards System (NMMSS). While LANMAS performs those functions well, there are many additional functions provided by the software product. As a material is received onto a site or created at a site, its entire lifecycle can be tracked in LANMAS complete to its termination of safeguards. There are separate functions to track material movements between and within material balance areas (MBAs). The level of detail for movements within a MBA is configurable by each site and can be as high as a site designation or as detailed as building/room/rack/row/position. Functionality exists to track the processing of materials, either as individual items or by modeling a bulk process as an individual item to track inputs and outputs from the process. In cases where sites have specialized needs, the system is designed to be flexible so that site specific functionality can be integrated into the product. This paper will demonstrate how the software can be used …
Date: June 7, 2010
Creator: Armstrong, F.
Object Type: Article
System: The UNT Digital Library
Magnetism in metal-organic capsules (open access)

Magnetism in metal-organic capsules

Nickel and cobalt seamed metal-organic capsules have been isolated and studied using structural, magnetic and computational approaches. Antiferromagnetic exchange in the Ni capsule results from coordination environments enforced by the capsule framework.
Date: January 7, 2010
Creator: Atwood, Jerry L.; Brechin, Euan K; Dalgarno, Scott J.; Inglis, Ross; Jones, Leigh F.; Mossine, Andrew et al.
Object Type: Article
System: The UNT Digital Library
Electron Positron Proton Spectrometer for use at Laboratory for Laser Energetics (open access)

Electron Positron Proton Spectrometer for use at Laboratory for Laser Energetics

The Electron Positron Proton Spectrometer (EPPS) is mounted in a TIM (Ten-Inch Manipulator) system on the Omega-60 or Omega-EP laser facilities at the University of Rochester, Laboratory for Laser Energetics (LLE), when in use, see Fig. 1. The Spectrometer assembly, shown in Fig. 2, is constructed of a steel box containing magnets, surrounded by Lead 6% Antimony shielding with SS threaded insert, sitting on an Aluminum 6061-T6 plate.
Date: April 7, 2010
Creator: Ayers, S L
Object Type: Report
System: The UNT Digital Library
Two-Photon Interactions with Nuclear Breakup in Relativistic Heavy Ion Collisions (open access)

Two-Photon Interactions with Nuclear Breakup in Relativistic Heavy Ion Collisions

Highly charged relativistic heavy ions have high cross-sections for two-photon interactions. The photon flux is high enough that two-photon interactions may be accompanied by additional photonuclear interactions. Except for the shared impact parameter, these interactions are independent. Additional interactions like mutual Coulomb excitation are of experimental interest, since the neutrons from the nuclear dissociation provide a simple, relatively unbiased trigger. We calculate the cross sections, rapidity, mass and transverse momentum (p{sub T}) distributions for exclusive {gamma}{gamma} production of mesons and lepton pairs, and for {gamma}{gamma} reactions accompanied by mutual Coulomb dissociation. The cross-sections for {gamma}{gamma} interactions accompanied by multiple neutron emission (XnXn) and single neutron emission (1n1n) are about 1/10 and 1/100 of that for the unaccompanied {gamma}{gamma} interactions. We discuss the accuracy with which these cross-sections may be calculated. The typical p{sub T} of {gamma}{gamma} final states is several times smaller than for comparable coherent photonuclear interactions, so p{sub T} may be an effective tool for separating the two classes of interactions.
Date: July 7, 2010
Creator: Baltz, Anthony J.; Gorbunov, Yuri; R Klein, Spencer & Nystrand, Joakim
Object Type: Article
System: The UNT Digital Library
Mill Seat Landfill Bioreactor Renewable Green Power (NY) (open access)

Mill Seat Landfill Bioreactor Renewable Green Power (NY)

The project was implemented at the Mill Seat landfill located in the Town of Bergen, Monroe County, New York. The landfill was previously equipped with a landfill gas collection system to collect methane gas produced by the bioreactor landfill and transport it to a central location for end use. A landfill gas to energy facility was also previously constructed at the site, which utilized generator engines, designed to be powered with landfill methane gas, to produce electricity, to be utilized on site and to be sold to the utility grid. The landfill gas generation rate at the site had exceeded the capacity of the existing generators, and the excess landfill gas was therefore being burned at a candlestick flare for destruction. The funded project consisted of the procurement and installation of two (2) additional 800 KW Caterpillar 3516 generator engines, generator sets, switchgear and ancillary equipment.
Date: January 7, 2010
Creator: Barton & Loguidice, P.C.
Object Type: Report
System: The UNT Digital Library
Intermolecular potential parameters and combining rules determined from viscosity data (open access)

Intermolecular potential parameters and combining rules determined from viscosity data

The Law of Corresponding States has been demonstrated for a number of pure substances and binary mixtures, and provides evidence that the transport properties viscosity and diffusion can be determined from a molecular shape function, often taken to be a Lennard-Jones 12-6 potential, that requires two scaling parameters: a well depth {var_epsilon}{sub ij} and a collision diameter {sigma}{sub ij}, both of which depend on the interacting species i and j. We obtain estimates for {var_epsilon}{sub ij} and {sigma}{sub ij} of interacting species by finding the values that provide the best fit to viscosity data for binary mixtures, and compare these to calculated parameters using several 'combining rules' that have been suggested for determining parameter values for binary collisions from parameter values that describe collisions of like molecules. Different combining rules give different values for {sigma}{sub ij} and {var_epsilon}{sub ij} and for some mixtures the differences between these values and the best-fit parameter values are rather large. There is a curve in ({var_epsilon}{sub ij}, {sigma}{sub ij}) space such that parameter values on the curve generate a calculated viscosity in good agreement with measurements for a pure gas or a binary mixture. The various combining rules produce couples of parameters {var_epsilon}{sub ij}, …
Date: May 7, 2010
Creator: Bastien, Lucas A.J.; Price, Phillip N. & Brown, Nancy J.
Object Type: Article
System: The UNT Digital Library
Measurement and Modeling of Blocking Contacts for Cadmium Telluride Gamma Ray Detectors (open access)

Measurement and Modeling of Blocking Contacts for Cadmium Telluride Gamma Ray Detectors

Gamma ray detectors are important in national security applications, medicine, and astronomy. Semiconductor materials with high density and atomic number, such as Cadmium Telluride (CdTe), offer a small device footprint, but their performance is limited by noise at room temperature; however, improved device design can decrease detector noise by reducing leakage current. This thesis characterizes and models two unique Schottky devices: one with an argon ion sputter etch before Schottky contact deposition and one without. Analysis of current versus voltage characteristics shows that thermionic emission alone does not describe these devices. This analysis points to reverse bias generation current or leakage through an inhomogeneous barrier. Modeling the devices in reverse bias with thermionic field emission and a leaky Schottky barrier yields good agreement with measurements. Also numerical modeling with a finite-element physics-based simulator suggests that reverse bias current is a combination of thermionic emission and generation. This thesis proposes further experiments to determine the correct model for reverse bias conduction. Understanding conduction mechanisms in these devices will help develop more reproducible contacts, reduce leakage current, and ultimately improve detector performance.
Date: January 7, 2010
Creator: Beck, P R
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Antibiotic Use in Agriculture: Background and Legislation (open access)

Antibiotic Use in Agriculture: Background and Legislation

This report deals with Antibiotic Use in Agriculture: Background and Legislation.
Date: January 7, 2010
Creator: Becker, Geoffrey S.
Object Type: Report
System: The UNT Digital Library
Landsat and the Data Continuity Mission (open access)

Landsat and the Data Continuity Mission

This report discusses the U.S. Landsat Mission, which has collected remotely sensed imagery of the Earth's surface for more than 35 years. The two satellites currently in orbit are operating beyond their designed life and may fail at any time. Most Landsat data is used by federal agencies. Efforts to commercialize Landsat operations have not been successful. This report discusses issues facing Congress regarding funding for new Landsat satellites.
Date: June 7, 2010
Creator: Behrens, Carl E.
Object Type: Report
System: The UNT Digital Library
Comparison of Poloidal Velocity Meassurements to Neoclassical Theory on the National Spherical Torus Experiment (open access)

Comparison of Poloidal Velocity Meassurements to Neoclassical Theory on the National Spherical Torus Experiment

Knowledge of poloidal velocity is necessary for the determination of the radial electric field, Er, which along with its gradient is linked to turbulence suppression and transport barrier formation. Recent measurements of poloidal flow on conventional tokamaks have been reported to be an order of magnitude larger than expected from neoclassical theory. In contrast, recent poloidal velocity measurements on the NSTX spherical torus [S. M. Kaye et al., Phys. Plasmas 8, 1977 (2001)] are near or below neoclassical estimates. A novel charge exchange recombination spectroscopy diagnostic is used, which features active and passive sets of up/down symmetric views to produce line-integrated poloidal velocity measurements that do not need atomic physics corrections. Local profiles are obtained with an inversion. Poloidal velocity measurements are compared with neoclassical values computed with the codes NCLASS [W. A. Houlberg et al., Phys. Plasmas 4, 3230 (1997)] and GTC-Neo [W. X. Wang, et al., Phys. Plasmas 13, 082501 (2006)], which has been updated to handle impurities. __________________________________________________
Date: April 7, 2010
Creator: Bell, R. E.; Kaye, S. M.; Kolesnikov, R. A.; LeBlance, B. P.; Rewolldt, G. & Wang, W. X.
Object Type: Report
System: The UNT Digital Library
Recent Results on Flavor Physics from BaBar (open access)

Recent Results on Flavor Physics from BaBar

The authors report an update to their previous measurement of the CKM element |V{sub ub}| using exclusive B {yields} {pi}{ell}{nu} decays. In the charm sector they have performed a measurement of f{sub D{sub s}} using D{sub s}{sup +} {yields} {tau}{sup +}{nu}{sub {tau}} decays, they have measured the mixing parameter y{sub CP} using the lifetime ratio <{tau}{sub K{pi}}>/<{tau}{sub hh}> in D{sup 0} decays, and they have also searched for CP violation using T-odd correlations in D{sup 0} decays to K{sup +}K{sup -}{pi}{sup +}{pi}{sup -}. Finally, in the tau sector they have performed a search for the lepton flavor violating decays {tau}{sup {+-}} {yields} e{sup {+-}}{gamma} and {tau}{sup {+-}} {yields} {mu}{sup {+-}}{gamma}.
Date: June 7, 2010
Creator: Benitez, Jose
Object Type: Article
System: The UNT Digital Library
Securing America's Borders: The Role of the Intelligence Community (open access)

Securing America's Borders: The Role of the Intelligence Community

Maintaining the security of U.S. borders is a fundamental responsibility of the federal government. This report discusses the contribution of intelligence agencies to the border security efforts of the Department of Homeland Security, the Department of Defense, and other federal agencies that work in cooperation with state, local, and tribal law enforcement agencies. Much of the intelligence community's border security-related efforts are classified, however.
Date: December 7, 2010
Creator: Best, Richard A., Jr.
Object Type: Report
System: The UNT Digital Library
American Jihadist Terrorism: Combating a Complex Threat (open access)

American Jihadist Terrorism: Combating a Complex Threat

This report describes homegrown violent jihadists and the plots and attacks that have occurred since 9/11. "Homegrown" and "domestic" are terms that describe terrorist activity or plots perpetrated within the United States or abroad by American citizens, legal permanent residents, or visitors radicalized largely within the United States. The report also discusses the radicalization process and the forces driving violent extremist activity. It analyzes post-9/11 domestic jihadist terrorism and describes law enforcement and intelligence efforts to combat terrorism and the challenges associated with those efforts.
Date: December 7, 2010
Creator: Bjelopera, Jerome P.
Object Type: Report
System: The UNT Digital Library
Femtosecond Diffractive Imaging with a Soft-X-Ray Free-Electron Laser (open access)

Femtosecond Diffractive Imaging with a Soft-X-Ray Free-Electron Laser

Theory predicts that with an ultrashort and extremely bright coherent X-ray pulse, a single diffraction pattern may be recorded from a large macromolecule, a virus, or a cell before the sample explodes and turns into a plasma. Here we report the first experimental demonstration of this principle using the FLASH soft X-ray free-electron laser. An intense 25 fs, 4 x 10{sup 13} W/cm{sup 2} pulse, containing 10{sup 12} photons at 32 nm wavelength, produced a coherent diffraction pattern from a nano-structured non-periodic object, before destroying it at 60,000 K. A novel X-ray camera assured single photon detection sensitivity by filtering out parasitic scattering and plasma radiation. The reconstructed image, obtained directly from the coherent pattern by phase retrieval through oversampling, shows no measurable damage, and extends to diffraction-limited resolution. A three-dimensional data set may be assembled from such images when copies of a reproducible sample are exposed to the beam one by one.
Date: October 7, 2010
Creator: Bogan, Michael James
Object Type: Article
System: The UNT Digital Library
Optical Design Considerations Relevant to Reflective UV Launch Gratings for Photocathode Irradiation (open access)

Optical Design Considerations Relevant to Reflective UV Launch Gratings for Photocathode Irradiation

The characteristics of photoelectron microbunches emitted from a photocathode in response to laser irradiation determine many of the incident laser pulse requirements. RF photocathode designs based on grazing incidence of the irradiation benefit from the removal of launch optics from the electron beamline and enhanced absorption at Brewster angles. However, this also introduces two well known complexities in the laser pulse 'launch' requirements: (i) a transverse spatial anamorphism to guarantee that the projected transverse spatial profile of the irradiation is circular (in the plane of the photocathode) and (ii) a 'time slew' or tilted amplitude front on the laser pulse that is incident on the photocathode to guarantee that the temporal (longitudinal) profiles are synchronous across the entire transverse irradiation profile in the photocathode plane. A single diffraction grating can be used to fulfill these combined requirements. This reported work focuses on grating behavior only. It does not address imaging requirements associated with relayed optical transport from the grating to the photocathode. Because the grating is a highly dispersive optical element by design, the dispersive aspects of all launch requirements are important.
Date: December 7, 2010
Creator: Bolton, Paul
Object Type: Report
System: The UNT Digital Library
Roller Cam Positioners (open access)

Roller Cam Positioners

Roller Cam Positioners could support the LCLS undulator sections allowing micron sized alignment adjustment of each undulator in 5 degrees of freedom. The supports are kinematic with the number of degrees of freedom matched to the number of constraints. Ton loads are supported on simple ball bearings. Motion is intrinsically bounded. Positioning mechanisms are based on pure rolling motion with sub-micron hysteresis and micron resolution. This note describes a general purpose positioning mechanism suitable for undulator support.
Date: December 7, 2010
Creator: Bowden, Gordon B.
Object Type: Report
System: The UNT Digital Library
Numerical Electromagnetics Simulations of the Leakage Through the Pump-out Holes in the DISC Electromagnetic Interference Shield (open access)

Numerical Electromagnetics Simulations of the Leakage Through the Pump-out Holes in the DISC Electromagnetic Interference Shield

None
Date: October 7, 2010
Creator: Brown, C G; Cooper, A & Moore, A S
Object Type: Report
System: The UNT Digital Library
Establishing Natural Product Content with the Natural Radiocarbon Signature (open access)

Establishing Natural Product Content with the Natural Radiocarbon Signature

None
Date: May 7, 2010
Creator: Buchholz, B. A.; Sarachine, M. J. & Zermeno, P.
Object Type: Book
System: The UNT Digital Library
Asian Carp and the Great Lakes Region (open access)

Asian Carp and the Great Lakes Region

This report describes non-indigenous Asian carp migrating to the United States, their potential impacts on the ecosystem, federal responses, and litigation.
Date: June 7, 2010
Creator: Buck, Eugene H.; Upton, Harold F.; Stern, Charles V. & Nichols, James E.
Object Type: Report
System: The UNT Digital Library
High Pressure - High Temperature Polymorphism in Ta: Resolving an Ongoing Experimental Controversy (open access)

High Pressure - High Temperature Polymorphism in Ta: Resolving an Ongoing Experimental Controversy

Phase diagrams of refractory metals remain essentially unknown. Moreover, there is an ongoing controversy over the high pressure (P) melting temperatures of these metals: results of diamond anvil cell (DAC) and shock wave experiments differ by at least a factor of two. From an extensive ab initio study on tantalum we discovered that the body-centered cubic phase, its physical phase at ambient conditions, transforms to another solid phase, possibly hexagonal omega phase, at high temperature (T). Hence the sample motion observed in DAC experiments is not due to melting but internal stresses accompanying a solid-solid transformation, as explained in more detail in our work. In view of our results on tantalum and previous work on molybdenum, as well as other published data, it is highly plausible that high-PT polymorphism is a general feature of Groups V and VI refractory metals.
Date: April 7, 2010
Creator: Burkovsky, L.; Chen, S. P.; Preston, D. L.; Belonoshko, A. B.; Rosengren, A.; Mikhaylushkin, A. S. et al.
Object Type: Article
System: The UNT Digital Library
Field Demonstration of Carbon Dioxide Miscible Flooding in the Lansing-Kansas City Formation, Central Kansas (open access)

Field Demonstration of Carbon Dioxide Miscible Flooding in the Lansing-Kansas City Formation, Central Kansas

A pilot carbon dioxide miscible flood was initiated in the Lansing Kansas City C formation in the Hall Gurney Field, Russell County, Kansas. The reservoir zone is an oomoldic carbonate located at a depth of about 2900 feet. The pilot consists of one carbon dioxide injection well and three production wells. Continuous carbon dioxide injection began on December 2, 2003. By the end of June 2005, 16.19 MM lb of carbon dioxide was injected into the pilot area. Injection was converted to water on June 21, 2005 to reduce operating costs to a breakeven level with the expectation that sufficient carbon dioxide was injected to displace the oil bank to the production wells by water injection. By March 7,2010, 8,736 bbl of oil were produced from the pilot. Production from wells to the northwest of the pilot region indicates that oil displaced from carbon dioxide injection was produced from Colliver A7, Colliver A3, Colliver A14 and Graham A4 located on adjacent leases. About 19,166 bbl of incremental oil were estimated to have been produced from these wells as of March 7, 2010. There is evidence of a directional permeability trend toward the NW through the pilot region. The majority of …
Date: March 7, 2010
Creator: Byrnes, Alan; Willhite, G. Paul; Green, Don; Pancake, Richard; Tsau, JyunSyung; Watney, W. Lynn et al.
Object Type: Report
System: The UNT Digital Library
Quantum Simulations for Dense Matter (open access)

Quantum Simulations for Dense Matter

High pressure systems are important, for example, to understand the interiors of giant planets (Jupiter and Saturn), for experiments at NIF (the National Ignition Facility at Livermore) related to inertially confined fusion and for other interests of DOE. In this project, we are developing innovative simulation methods (Quantum Monte Carlo methods) to allow more accurate calculation of properties of systems under extreme conditions of pressure and temperature. These methods can use the power of current day supercomputers made of very many processors, starting from the basic equations of physics to model quantum phenomena important at the microscopic scale. During the grant period, we have settled two important questions of the physics of hydrogen and helium under extreme conditions. We have found the pressures and temperatures when hydrogen and helium mix together; this is important to understand the difference of the interiors of the planets Jupiter and Saturn. Secondly, we have shown that there exists a sharp transition as a function of pressure between molecular and atomic liquid hydrogen at temperatures below 2000K. This prediction can be confirmed with high pressure experiments.
Date: June 7, 2010
Creator: Ceperley, David M.
Object Type: Report
System: The UNT Digital Library