IRON-PHOSPHATE GLASS FOR IMMOBILIZATION OF RADIOACTIVE TECHNETIUM (open access)

IRON-PHOSPHATE GLASS FOR IMMOBILIZATION OF RADIOACTIVE TECHNETIUM

Technetium-99 (Tc-99) can bring a serious environmental threat because of its high fission yield, long half-life, and high solubility and mobility in the ground water. The present work investigated the immobilization of Tc-99 (surrogated by Re) by heat-treating mixtures of an iron-phosphate glass with 1.5 to 6 wt.% KReO{sub 4} at {approx}1000 C. The Re retention in the glass was as high as {approx}1.2 wt. % while the loss of Re by evaporation during melting was {approx}50%. Re was uniformly distributed within the glass. The normalized Re release by the 7-day Product Consistency Test was {approx}0.39 g/m{sup 2}, comparable with that in phosphate-bonded ceramics and borosilicate glasses. These results suggest that iron-phosphate glass can provide a good matrix for immobilizing Tc-99.
Date: March 19, 2012
Creator: AA, KRUGER; PR, HRMA; K, XU; J, CHOI; W, UM & J, HEO
Object Type: Article
System: The UNT Digital Library
Constraints on Dark Matter Models From a Fermi LAT Search for High-Energy Cosmic-Ray Electrons from the Sun (open access)

Constraints on Dark Matter Models From a Fermi LAT Search for High-Energy Cosmic-Ray Electrons from the Sun

None
Date: March 19, 2013
Creator: Ajello, M.; Atwood, W. B.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bellazzini, R. et al.
Object Type: Article
System: The UNT Digital Library
Energy savings by means of fuel cell electrodes in electro-chemical industries (open access)

Energy savings by means of fuel cell electrodes in electro-chemical industries

In addition to consultations with interested organizations, data are presented for air depolarized cathode performance in caustic half cells and hydrogen depolarization of anodes for the electrowinning of zinc. Investigation with air depolarized Pt cathodes in caustic half cells include: progress of the one year old RA19 type air diffusion cathode; data involving incorporation of a Hg/HgO reference electrode into the standard hardware; studies investigating cathode loading vs. cell performance; continued evaluation of thin, porous, conducting substrates; and cathode performance as a function of electrolyte concentration. In the area of zinc electrowinning, short term tests (4 hours) with pure hydrogen feeds have been carried out under various cell operating conditions. In addition, tests with CO-containing hydrogen have been initiated utilizing different levels of carbon monoxide poison. A preliminary Economic Evaluation for Electric Energy savings versus hydrogen costs is presented.
Date: March 19, 1979
Creator: Allen, R. J.; Juda, W.; Lindstrom, R. W. & Petrow, H. G.
Object Type: Report
System: The UNT Digital Library
Lower thrust structure S/N 0000012 structural test evaluation (open access)

Lower thrust structure S/N 0000012 structural test evaluation

None
Date: March 19, 1966
Creator: Allgair, E.H.
Object Type: Report
System: The UNT Digital Library
Beam Extraction from Laser Driven Multi-Charged Ion Source (open access)

Beam Extraction from Laser Driven Multi-Charged Ion Source

A newly proposed type of multicharged ion source offers the possibility of an economically advantageous high-charge-state fusion driver. Multiphoton absorption in an intense uniform laser focus can give multiple charge states of high purity, simplifying or eliminating the need for charge-state separation downstream. Very large currents (hundreds of amperes) can be extracted from this type of source. Several arrangements are possible. For example, the laser plasma could be tailored for storage in a magnetic bucket, with beam extracted from the bucket. A different approach, described in this report, is direct beam extraction from the expanding laser plasma. They discuss extraction and focusing for the particular case of a 4.1-MV beam of Xe{sup 16+} ions. The maximum duration of the beam pulse is limited by the total charge in the plasma, while the practical pulse length is determined by the range of plasma radii over which good beam optics can be achieved. The extraction electrode contains a solenoid for beam focusing. The design studies were carried out first with an envelope code and then with a self-consistent particle code. Results from the initial model showed that hundreds of amperes could be extracted, but that most of this current missed the solenoid …
Date: March 19, 2001
Creator: Anderson, O. A. & Logan, B. G.
Object Type: Article
System: The UNT Digital Library
Survey of the ATLAS Pixel Detector Components (open access)

Survey of the ATLAS Pixel Detector Components

This document provides a description of the survey performed on different componentsof the ATLAS Pixel Detector at different stages of its assembly.
Date: March 19, 2008
Creator: Andreazza, Attilio; Kostyukhim, Vadim & Madaras, Ronald
Object Type: Report
System: The UNT Digital Library
ASIC Wafer Test System for the ATLAS Semiconductor Tracker Front-End Chip (open access)

ASIC Wafer Test System for the ATLAS Semiconductor Tracker Front-End Chip

An ASIC wafer test system has been developed to provide comprehensive production screening of the ATLAS Semiconductor Tracker front-end chip (ABCD3T). The ABCD3T[1] features a 128-channel analog front-end, a digital pipeline, and communication circuitry, clocked at 40 MHz, which is the bunch crossing frequency at the LHC (Large Hadron Collider). The tester measures values and tolerance ranges of all critical IC parameters, including DC parameters, electronic noise, time resolution, clock levels and clock timing. The tester is controlled by an FPGA (ORCA3T) programmed to issue the input commands to the IC and to interpret the output data. This allows the high-speed wafer-level IC testing necessary to meet the production schedule. To characterize signal amplitudes and phase margins, the tester utilizes pin-driver, delay, and DAC chips, which control the amplitudes and delays of signals sent to the IC under test. Output signals from the IC under test go through window comparator chips to measure their levels. A probe card has been designed specifically to reduce pick-up noise that can affect the measurements. The system can operate at frequencies up to 100 MHz to study the speed limits of the digital circuitry before and after radiation damage. Testing requirements and design solutions …
Date: March 19, 2002
Creator: Anghinolfi, F.; Bialas, W.; Busek, N.; Ciocio, A.; Cosgrove, D.; Fadeyev, V. et al.
Object Type: Article
System: The UNT Digital Library
A Study of Past, Present, and Future Radiation Dose Pathways from Hanford Site Effluents (open access)

A Study of Past, Present, and Future Radiation Dose Pathways from Hanford Site Effluents

The purpose of this study is to determine whether changes to Hanford operations, as well as changes in the regulatory environment, will require new approaches to ensure radiation protection of the public and the environment. This document discusses the applicable regulations that govern public radiation protection at DOE facilities, recent radiological assessments for members of the public near the Hanford Site, and possible new approaches that may be needed to assure that the Hanford Site can demonstrate compliance with regulatory requirements for radiological protection of the public.
Date: March 19, 2002
Creator: Antonio, Ernest J.; Rhoads, Kathleen & Staven, Lissa H.
Object Type: Report
System: The UNT Digital Library
Mathematical modeling of the effects of aerobic and anaerobic chelate bioegradation on actinide speciation. (open access)

Mathematical modeling of the effects of aerobic and anaerobic chelate bioegradation on actinide speciation.

Biodegradation of natural and anthropogenic chelating agents directly and indirectly affects the speciation, and, hence, the mobility of actinides in subsurface environments. We combined mathematical modeling with laboratory experimentation to investigate the effects of aerobic and anaerobic chelate biodegradation on actinide [Np(IV/V), Pu(IV)] speciation. Under aerobic conditions, nitrilotriacetic acid (NTA) biodegradation rates were strongly influenced by the actinide concentration. Actinide-chelate complexation reduced the relative abundance of available growth substrate in solution and actinide species present or released during chelate degradation were toxic to the organisms. Aerobic bio-utilization of the chelates as electron-donor substrates directly affected actinide speciation by releasing the radionuclides from complexed form into solution, where their fate was controlled by inorganic ligands in the system. Actinide speciation was also indirectly affected by pH changes caused by organic biodegradation. The two concurrent processes of organic biodegradation and actinide aqueous chemistry were accurately linked and described using CCBATCH, a computer model developed at Northwestern University to investigate the dynamics of coupled biological and chemical reactions in mixed waste subsurface environments. CCBATCH was then used to simulate the fate of Np during anaerobic citrate biodegradation. The modeling studies suggested that, under some conditions, chelate degradation can increase Np(IV) solubility due to …
Date: March 19, 1998
Creator: Banaszak, J.E.; VanBriesen, J.; Rittmann, B.E. & Reed, D.T.
Object Type: Article
System: The UNT Digital Library
Important atomic physics issues for ion beam fusion (open access)

Important atomic physics issues for ion beam fusion

This paper suggests several current atomic physics questions important to ion beam fusion. Among the topics discussed are beam transport, beam-target interaction, and reactor design. The major part of the report is discussion concerning areas of research necessary to better understand beam-target interactions. (JDH)
Date: March 19, 1985
Creator: Bangerter, Roger O.
Object Type: Article
System: The UNT Digital Library
Structural characterization of terrestrial microbial Mn oxides from Pinal Creek, AZ (open access)

Structural characterization of terrestrial microbial Mn oxides from Pinal Creek, AZ

The microbial catalysis of Mn(II) oxidation is believed to be a dominant source of abundant sorption- and redox-active Mn oxides in marine, freshwater, and subsurface aquatic environments. In spite of their importance, environmental oxides of known biogenic origin have generally not been characterized in detail from a structural perspective. Hyporheic zone Mn oxide grain coatings at Pinal Creek, Arizona, a metals-contaminated stream, have been identified as being dominantly microbial in origin and are well studied from bulk chemistry and contaminant hydrology perspectives. This site thus presents an excellent opportunity to study the structures of terrestrial microbial Mn oxides in detail. XRD and EXAFS measurements performed in this study indicate that the hydrated Pinal Creek Mn oxide grain coatings are layer-type Mn oxides with dominantly hexagonal or pseudo-hexagonal layer symmetry. XRD and TEM measurements suggest the oxides to be nanoparticulate plates with average dimensions on the order of 11 nm thick x 35 nm diameter, but with individual particles exhibiting thickness as small as a single layer and sheets as wide as 500 nm. The hydrated oxides exhibit a 10-A basal-plane spacing and turbostratic disorder. EXAFS analyses suggest the oxides contain layer Mn(IV) site vacancy defects, and layer Mn(III) is inferred …
Date: March 19, 2008
Creator: Bargar, John; Fuller, Christopher; Marcus, Matthew A.; Brearley, Adrian J.; Perez De la Rosa, M.; Webb, Samuel M. et al.
Object Type: Article
System: The UNT Digital Library
Simulations for experimental study of warm dense matter and inertial fusion energy applications on NDCX-II (open access)

Simulations for experimental study of warm dense matter and inertial fusion energy applications on NDCX-II

The Neutralized Drift Compression Experiment II (NDCX II) is an induction accelerator planned for initial commissioning in 2012. The final design calls for a {approx}3 MeV, {approx}30 A Li{sup +} ion beam, delivered in a bunch with characteristic pulse duration of 1 ns, and transverse dimension of order 1 mm. The purpose of NDCX II is to carry out experimental studies of material in the warm dense matter regime, and ion beam/hydrodynamic coupling experiments relevant to heavy ion based inertial fusion energy. In preparation for this new machine, we have carried out hydrodynamic simulations of ion-beam-heated, metallic solid targets, connecting quantities related to observables, such as brightness temperature and expansion velocity at the critical frequency, with the simulated fluid density, temperature, and velocity. We examine how these quantities depend on two commonly used equations of state.
Date: March 19, 2010
Creator: Barnard, J. J.; Armijo, J.; Bieniosek, F. M.; Friedman, A.; Hay, M. J.; Henestroza, E. et al.
Object Type: Article
System: The UNT Digital Library
An Evaluation of the Uranium Contamination on the Surfaces of Alclad Uranium-Aluminum Alloy Research Reactor Fuel Plates (open access)

An Evaluation of the Uranium Contamination on the Surfaces of Alclad Uranium-Aluminum Alloy Research Reactor Fuel Plates

Reported radioactivity in the Low-Intensity Test Reactor (LITR) water coolant traceable to uranium contamination on the surfaces of the alclad uranium-- aluminum plate-tyne fuel element led to an investigation to determine the sources of uranium contamination on the fuel plate surfaces. Two possible contributors to surface contamination are external sources such as rolling-mill equipment, the most obvious, and diffusion of uranium from the uranium-aluminum alloy fuel into the aluminum cladding. This diffusion is likely because of the 600 deg C heat treatments used in the conventional fabrication process. Uranium determinations based on neutron activation analysis of machined layers from fuel plate surfaces showed that rolling-mill equipment, contaminated with highly enriched uranium, was responsible for transferring as much as 180 ppm U to plate surfaces. By careful practice where cleanliness is emphasized, surface contamination can be reduced to 0.6 ppm U/sup 235/. The residue remaining on the plate surface may be accounted for by diffusion of uranium from the fuel alloy into and through the cladding of the fuel plate. Data obtained from preliminary diffusion studies permitted a good estimate to be made of the diffusion coefficient of uranium into aluminum at 600 deg C: 2.5 x 10/sup -8/ cm//sec. To …
Date: March 19, 1962
Creator: Beaver, R. J.; Erwin, J. H. & Mateer, R. S.
Object Type: Report
System: The UNT Digital Library
BRCA1 loss pre-existing in small subpopulations of prostate cancer is associated with advanced disease and metastatic spread to lymph nodes and peripheral blood (open access)

BRCA1 loss pre-existing in small subpopulations of prostate cancer is associated with advanced disease and metastatic spread to lymph nodes and peripheral blood

A recent study concluded that serum prostate specific antigen (PSA)-based screening is beneficial for reducing the lethality of PCa, but was also associated with a high risk of 'overdiagnosis'. Nevertheless, also PCa patients who suffered from organ confined tumors and had negative bone scans succumb to distant metastases after complete tumor resection. It is reasonable to assume that those tumors spread to other organs long before the overt manifestation of metastases. Our current results confirm that prostate tumors are highly heterogeneous. Even a small subpopulation of cells bearing BRCA1 losses can initiate PCa cell regional and distant dissemination indicating those patients which might be at high risk of metastasis. A preliminary study performed on a small cohort of multifocal prostate cancer (PCa) detected BRCA1 allelic imbalances (AI) among circulating tumor cells (CTCs). The present analysis was aimed to elucidate the biological and clinical role of BRCA1 losses on metastatic spread and tumor progression in prostate cancer patients. Experimental Design: To map molecular progression in PCa outgrowth we used FISH analysis of tissue microarrays (TMA), lymph node sections and CTC from peripheral blood. We found that 14% of 133 tested patients carried monoallelic BRCA1 loss in at least one tumor focus. …
Date: March 19, 2010
Creator: Bednarz, Natalia; Eltze, Elke; Semjonow, Axel; Rink, Michael; Andreas, Antje; Mulder, Lennart et al.
Object Type: Report
System: The UNT Digital Library
DSDP3: dual scaling algorithm for general positive semidefinite programming. (open access)

DSDP3: dual scaling algorithm for general positive semidefinite programming.

We implement a dual scaling algorithm for positive semidefinite programming to handle a broader class of problems than could be solved with previous implementations of the algorithm. With appropriate representations of constraint matrices, we can solve general semidefinite programs and still exploit the structure of large-scale combinatorial optimization problems. Computational results show that our preliminary implementation is competitive with primal-dual solvers on many problems requiring moderate precision in the solution and is superior to primal-dual solvers for several types of problems.
Date: March 19, 2001
Creator: Benson, S.J. & Ye, Y.
Object Type: Article
System: The UNT Digital Library
SUSY Production cross sections. (open access)

SUSY Production cross sections.

We summarize the status of next-to-leading order perturbative quantum chromodynamics (pQCD) calculations of the cross sections for the production of squarks, gluinos, neutralinos, charginos, and sleptons as a function of the produced particle masses in proton-antiproton collisions at the hadronic center-of-mass energy 2 TeV.
Date: March 19, 1999
Creator: Berger, E. L.; Harris, B.; Klasen, M. & Tait, T.
Object Type: Article
System: The UNT Digital Library
Gap Workshop Report (open access)

Gap Workshop Report

None
Date: March 19, 2012
Creator: Blink, J. A. & Budnitz, R J
Object Type: Report
System: The UNT Digital Library
Permitting plan for Hanford Tanks Initiative (open access)

Permitting plan for Hanford Tanks Initiative

This plan describes all the permitting actions that have been identified as required to implement the Hanford Tanks Initiative. It reflects changes in the scope to the Hanford Tanks Initiative since the Rev. 0 plan was issued. The cost and schedule for the permitting actions are included.
Date: March 19, 1998
Creator: Bloom, J.W.
Object Type: Report
System: The UNT Digital Library
Production of dense vapor targets for laser-plasma interaction studies with intense, ultra-short pulses (open access)

Production of dense vapor targets for laser-plasma interaction studies with intense, ultra-short pulses

The technique of laser-induced ablation of thin films from glass slide substrates has been investigated as a candidate vapor target production method for studies of both tunneling-driven x-ray/xuv recombination lasers and relativistic propagation using intense, ultra-short laser pulses. It is shown by simultaneous two-wavelength interferometry that particle densities of order 10{sup 19}/cm{sup 3} are readily achieved and that some intrinsic ionization accompanies the plume formation. Absorption measurements with both 100 picosecond and 125 femtosecond pulses are consistent with observed edge velocities near 10{sup 6} cm/sec. The level of ionization driven by the intense 125 femtosecond laser pulse has been coarsely estimated. Averaged estimates from spectral blue shifting of spectra transmitted through the plume are consistently lower than those obtained from evaluation of saturation intensity thresholds based on the sequential nonresonant optical field ionization (OFI) process.
Date: March 19, 1993
Creator: Bolton, P. R.; Eder, D. C.; Guethlein, G.; Stewart, R. E. & Young, P. E.
Object Type: Article
System: The UNT Digital Library
Maximum fuel temperature with one coolant channel blocked (open access)

Maximum fuel temperature with one coolant channel blocked

None
Date: March 19, 1962
Creator: Boman, L.H.
Object Type: Report
System: The UNT Digital Library
Investigation of the Richtmyer-Meshkov instability (open access)

Investigation of the Richtmyer-Meshkov instability

The present research program is centered on the experimental and numerical study of the hydrodynamics of shock-accelerated spherical density inhomogeneities. These flows are part of a broader category of shock-induced mixing flows that play a critical role in the implosion of D-T pellets in laser-driven ICF experiments. For the past year, our work has consisted of both experimental and numerical activities which were presented at two conferences and resulted in the publication of one journal article and the submission of a second one. The papers from one of the conferences are inlcuded here.
Date: March 19, 2007
Creator: Bonazza, Riccardo; Anderson, Mark & Oakley, Jason
Object Type: Report
System: The UNT Digital Library
The High Temperature Oxidation of Zircaloy in Water (open access)

The High Temperature Oxidation of Zircaloy in Water

None
Date: March 19, 1954
Creator: Bostrom, W. A.
Object Type: Report
System: The UNT Digital Library
Heavy-Water-Moderated Power Reactors Cooled by Liquid D$sub 2$O or H$sub 2$O (open access)

Heavy-Water-Moderated Power Reactors Cooled by Liquid D$sub 2$O or H$sub 2$O

None
Date: March 19, 1964
Creator: Boswell, J. M.; Holmes, W. G.; Hood, R. R.; Ross, C. P.; St. John, D. S. & Wade, J. W.
Object Type: Report
System: The UNT Digital Library
Effects of Restoration Techniques on Breeding Birds in Thermally-Impacted Bottomland Hardwood Forests (open access)

Effects of Restoration Techniques on Breeding Birds in Thermally-Impacted Bottomland Hardwood Forests

Breeding birds were studied in the Pen Branch riparian corridor following site preparation using herbicides and burning to control willow and improve access for planting. Compared with control strips, treated areas supported a greater richness and abundance of breeding birds. The community composition was representative of early successional bottomland forests.
Date: March 19, 1999
Creator: Buffington, J. M.; Kilgo, J. C.; Sargent, R. A.; Miller, K. V. & Chapman, B. R.
Object Type: Article
System: The UNT Digital Library