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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
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.
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.
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.
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
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.
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
System: The UNT Digital Library
Temperature-dependent structural heterogeneity in calcium silicate liquids (open access)

Temperature-dependent structural heterogeneity in calcium silicate liquids

This article discusses temperature-dependent structural heterogeneity in calcium silicate liquids.
Date: December 7, 2010
Creator: Benmore, Chris J.; Weber, J. K. R.; Wilding, Martin C.; Du, Jincheng & Parise, John B.
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
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.
System: The UNT Digital Library
Ultraviolet Behavior of N = 8 supergravity (open access)

Ultraviolet Behavior of N = 8 supergravity

In these lectures the author describes the remarkable ultraviolet behavior of N = 8 supergravity, which through four loops is no worse than that of N = 4 super-Yang-Mills theory (a finite theory). I also explain the computational tools that allow multi-loop amplitudes to be evaluated in this theory - the KLT relations and the unitarity method - and sketch how ultraviolet divergences are extracted from the amplitudes.
Date: June 7, 2010
Creator: Dixon, Lance J.
System: The UNT Digital Library
Initial Eccentricity in Deformed 197Au+197Au and 238U+238U Collisions at RHIC (open access)

Initial Eccentricity in Deformed 197Au+197Au and 238U+238U Collisions at RHIC

Initial eccentricity and eccentricity fluctuations of the interaction volume created in relativistic collisions of deformed {sup 197}Au and {sup 238}U nuclei are studied using optical and Monte-Carlo (MC) Glauber simulations. It is found that the non-sphericity noticeably influences the average eccentricity in central collisions and eccentricity fluctuations are enhanced due to deformation. Quantitative results are obtained for Au+Au and U+U collisions at energy {radical}s{sub NN} = 200 GeV.
Date: July 7, 2010
Creator: Filip, Peter; Lednicky, Richard; Masui, Hiroshi & Xu, Nu
System: The UNT Digital Library
RETENTION OF SULFATE IN HIGH LEVEL RADIOACTIVE WASTE GLASS (open access)

RETENTION OF SULFATE IN HIGH LEVEL RADIOACTIVE WASTE GLASS

High level radioactive wastes are being vitrified at the Savannah River Site for long term disposal. Many of the wastes contain sulfate at concentrations that can be difficult to retain in borosilicate glass. This study involves efforts to optimize the composition of a glass frit for combination with the waste to improve sulfate retention while meeting other process and product performance constraints. The fabrication and characterization of several series of simulated waste glasses are described. The experiments are detailed chronologically, to provide insight into part of the engineering studies used in developing frit compositions for an operating high level waste vitrification facility. The results lead to the recommendation of a specific frit composition and a concentration limit for sulfate in the glass for the next batch of sludge to be processed at Savannah River.
Date: September 7, 2010
Creator: Fox, K.
System: The UNT Digital Library
I/O Performance of a Large-Scale, Interpreter-Driven Laser-Plasma Interaction Code (open access)

I/O Performance of a Large-Scale, Interpreter-Driven Laser-Plasma Interaction Code

None
Date: April 7, 2010
Creator: Gamblin, T; Langer, S H; Still, B; Hedges, R; Schulz, M & de Supinski, B R
System: The UNT Digital Library
Underwater Blast Experiments and Modeling for Shock Mitigation (open access)

Underwater Blast Experiments and Modeling for Shock Mitigation

A simple but novel mitigation concept to enforce standoff distance and reduce shock loading on a vertical, partially-submerged structure is evaluated using scaled aquarium experiments and numerical modeling. Scaled, water tamped explosive experiments were performed using three gallon aquariums. The effectiveness of different mitigation configurations, including air-filled media and an air gap, is assessed relative to an unmitigated detonation using the same charge weight and standoff distance. Experiments using an air-filled media mitigation concept were found to effectively dampen the explosive response of the aluminum plate and reduce the final displacement at plate center by approximately half. The finite element model used for the initial experimental design compares very well to the experimental DIC results both spatially and temporally. Details of the experiment and finite element aquarium models are described including the boundary conditions, Eulerian and Lagrangian techniques, detonation models, experimental design and test diagnostics.
Date: March 7, 2010
Creator: Glascoe, L; McMichael, L; Vandersall, K & Margraf, J
System: The UNT Digital Library
ENHANCEMENT OF ENVIRONMENTAL SAMPLING THROUGH AN IMPROVED AIR MONITORING TECHNIQUE (open access)

ENHANCEMENT OF ENVIRONMENTAL SAMPLING THROUGH AN IMPROVED AIR MONITORING TECHNIQUE

Environmental sampling (ES) is a key component of International Atomic Energy Agency (IAEA) safeguarding approaches throughout the world. Performance of ES (e.g. air, water, vegetation, sediments, soil and biota) supports the IAEAs mission of drawing conclusions concerning the absence of undeclared nuclear material or nuclear activities in a State and has been available since the introduction of safeguards strengthening measures approved by the IAEA Board of Governors (1992-1997). A recent step-change improvement in the gathering and analysis of air samples at uranium/plutonium bulk handling facilities is an important addition to the international nuclear safeguards inspector's toolkit. Utilizing commonly used equipment throughout the IAEA network of analytical laboratories for particle analysis, researchers are developing the next generation of ES equipment for air grab and constant samples. Isotopic analysis of collected particles from an Aerosol Contaminant Extractor (ACE) silicon substrate has been performed with excellent results in determining attribute and isotopic composition of chemical elements present in an actual test-bed sample. The new collection equipment will allow IAEA nuclear safeguards inspectors to develop enhanced safeguarding approaches for complicated facilities. This paper will explore the use of air monitoring to establish a baseline environmental signature of a particular facility that could be used …
Date: June 7, 2010
Creator: Hanks, D.
System: The UNT Digital Library
SECURITY MODELING FOR MARITIME PORT DEFENSE RESOURCE ALLOCATION (open access)

SECURITY MODELING FOR MARITIME PORT DEFENSE RESOURCE ALLOCATION

Redeployment of existing law enforcement resources and optimal use of geographic terrain are examined for countering the threat of a maritime based small-vessel radiological or nuclear attack. The evaluation was based on modeling conducted by the Savannah River National Laboratory that involved the development of options for defensive resource allocation that can reduce the risk of a maritime based radiological or nuclear threat. A diverse range of potential attack scenarios has been assessed. As a result of identifying vulnerable pathways, effective countermeasures can be deployed using current resources. The modeling involved the use of the Automated Vulnerability Evaluation for Risks of Terrorism (AVERT{reg_sign}) software to conduct computer based simulation modeling. The models provided estimates for the probability of encountering an adversary based on allocated resources including response boats, patrol boats and helicopters over various environmental conditions including day, night, rough seas and various traffic flow rates.
Date: September 7, 2010
Creator: Harris, S. & Dunn, D.
System: The UNT Digital Library
A Bayesian Approach to Multi-Sensor Track Correlation (open access)

A Bayesian Approach to Multi-Sensor Track Correlation

None
Date: September 7, 2010
Creator: Horsley, M
System: The UNT Digital Library
A Parallel, High-Fidelity Radar Model (open access)

A Parallel, High-Fidelity Radar Model

None
Date: September 7, 2010
Creator: Horsley, M & Fasenfest, B
System: The UNT Digital Library
Cleanroom Energy Efficiency: Metrics and Benchmarks (open access)

Cleanroom Energy Efficiency: Metrics and Benchmarks

Cleanrooms are among the most energy-intensive types of facilities. This is primarily due to the cleanliness requirements that result in high airflow rates and system static pressures, as well as process requirements that result in high cooling loads. Various studies have shown that there is a wide range of cleanroom energy efficiencies and that facility managers may not be aware of how energy efficient their cleanroom facility can be relative to other cleanroom facilities with the same cleanliness requirements. Metrics and benchmarks are an effective way to compare one facility to another and to track the performance of a given facility over time. This article presents the key metrics and benchmarks that facility managers can use to assess, track, and manage their cleanroom energy efficiency or to set energy efficiency targets for new construction. These include system-level metrics such as air change rates, air handling W/cfm, and filter pressure drops. Operational data are presented from over 20 different cleanrooms that were benchmarked with these metrics and that are part of the cleanroom benchmark dataset maintained by Lawrence Berkeley National Laboratory (LBNL). Overall production efficiency metrics for cleanrooms in 28 semiconductor manufacturing facilities in the United States and recorded in the …
Date: July 7, 2010
Creator: Initiative, International SEMATECH Manufacturing; Mathew, Paul A.; Tschudi, William; Sartor, Dale & Beasley, James
System: The UNT Digital Library
Heat Pipe Embedded AlSiC Plates for High Conductivity - Low CTE Heat Spreaders (open access)

Heat Pipe Embedded AlSiC Plates for High Conductivity - Low CTE Heat Spreaders

Heat pipe embedded aluminum silicon carbide (AlSiC) plates are innovative heat spreaders that provide high thermal conductivity and low coefficient of thermal expansion (CTE). Since heat pipes are two phase devices, they demonstrate effective thermal conductivities ranging between 50,000 and 200,000 W/m-K, depending on the heat pipe length. Installing heat pipes into an AlSiC plate dramatically increases the plate’s effective thermal conductivity. AlSiC plates alone have a thermal conductivity of roughly 200 W/m-K and a CTE ranging from 7-12 ppm/ deg C, similar to that of silicon. An equivalent sized heat pipe embedded AlSiC plate has effective thermal conductivity ranging from 400 to 500 W/m-K and retains the CTE of AlSiC.
Date: January 7, 2010
Creator: Johnson, Matthew; Weyant, J.; Garner, S. & Occhionero, M.
System: The UNT Digital Library
HANFORDS PUBLIC TOUR PROGRAM - AN EXCELLENT EDUCATIONAL TOOL (open access)

HANFORDS PUBLIC TOUR PROGRAM - AN EXCELLENT EDUCATIONAL TOOL

Prior to 2001, the Department of Energy (DOE) sponsored limited tours of the Hanford Site for the public, but discontinued the program after the 9/11 terrorist attacks on the U.S. In 2003, DOE's Richland Operations Office (DOE-RL) requested the site's prime contractor to reinstate the public tour program starting in 2004 under strict controls and security requirements. The planning involved a collaborative effort among the security, safety and communications departments of DOE-RL and the site's contracting companies. This paper describes the evolution of, and enhancements to, Hanford's public tours, including the addition of a separate tour program for the B Reactor, the first full-scale nuclear reactor in the world. Topics included in the discussion include the history and growth of the tour program, associated costs, and visitor surveys and assessments.
Date: December 7, 2010
Creator: KM, SINCLAIR
System: The UNT Digital Library
Lifetime Tests on a High Ohms/Square Metalized High Crystalline Polypropylene Film Capacitor with Application to a Marx Modulator (open access)

Lifetime Tests on a High Ohms/Square Metalized High Crystalline Polypropylene Film Capacitor with Application to a Marx Modulator

This paper presents accelerated lifetime tests on a polypropylene film capacitor. Experimental parameters (20% droop, 5 Hz repetition rate) simulate anticipated operating conditions encountered in the SLAC P2 Marx. Elevated film electric field stress is utilized as the acceleration parameter. Results indicate that, for the particular film of interest, a film stress of {approx}290 V/{mu}m corresponds to a 10{sup 5} hour lifetime. In addition, the voltage scaling exponent for this film is 13.1.
Date: June 7, 2010
Creator: Kemp, Mark A.; Burkhart, Craig & Tang, Tao
System: The UNT Digital Library
Overview of Fusion-Fission Hybrid Blankets for Laser Inertial Fusion Energy (LIFE) Engine (open access)

Overview of Fusion-Fission Hybrid Blankets for Laser Inertial Fusion Energy (LIFE) Engine

None
Date: December 7, 2010
Creator: Kramer, K. J.; Fratoni, M.; Latkowski, J. F.; Abbott, R. P.; Havstad, M. A.; Anklam, T. M. et al.
System: The UNT Digital Library