Electron Correlation Effects in Uranium Dioxide from X-ray Emission Spectroscopy (open access)

Electron Correlation Effects in Uranium Dioxide from X-ray Emission Spectroscopy

None
Date: June 11, 2012
Creator: Yu, S W & Tobin, J G
System: The UNT Digital Library
Comparison of H-Mode Plasmas Diverted to Solid and Liquid Lithium Surfaces (open access)

Comparison of H-Mode Plasmas Diverted to Solid and Liquid Lithium Surfaces

None
Date: June 11, 2012
Creator: et. al, R K
System: The UNT Digital Library
REDUCTION AND SEQUESTRATION OF PERTECHNETATE TO TECHNETIUM DIOXIDE AND PROTECTION FROM RE-OXIDATION (open access)

REDUCTION AND SEQUESTRATION OF PERTECHNETATE TO TECHNETIUM DIOXIDE AND PROTECTION FROM RE-OXIDATION

This effort is part of the technetium management initiative and provides data for the handling and disposition of technetium. To that end, the objective of this effort was to challenge tin(II)apatite (Sn(II)apatite) against double-shell tank 241-AN-I0S simulant spiked with pertechnetate (TcO{sub 4}{sup -}). The Sn(II)apatite used in this effort was synthesized on site using a recipe developed at and provided by Sandia National Laboratories; the synthesis provides a high quality product while requiring minimal laboratory effort. The Sn(II)apatite reduces pertechnetate from the mobile +7 oxidation state to the non-mobile +4 oxidation state. It also sequesters the technetium and does not allow for re-oxidization to the mobile +7 state under acidic or oxygenated conditions within the tested period of time (6 weeks). Previous work indicated that the Sn(II)apatite can achieve an ANSI leachability index in Cast Stone of 12.8. The technetium distribution coefficient for Sn(II)apatite exhibits a direct correlation with the pH of the contaminated media. Table 1 shows Sn(II)apatite distribution coefficients as a function of pH. The asterisked numbers indicate that the lower detection limit of the analytical instrument was used to calculate the distribution coefficient as the concentration of technetium left in solution was less than the detection limit.
Date: July 11, 2012
Creator: JB, DUNCAN; JM, JOHNSON; WP, MOORE; KJ, HAGERTY; RN, RHODES & RC, MOORE
System: The UNT Digital Library
The Connection between Galaxies and Dark Matter Structures in the Local Universe (open access)

The Connection between Galaxies and Dark Matter Structures in the Local Universe

We provide new constraints on the connection between galaxies in the local Universe, identified by the Sloan Digital Sky Survey (SDSS), and dark matter halos and their constituent substructures in the {Lambda}CDM model using WMAP7 cosmological parameters. Predictions for the abundance and clustering properties of dark matter halos, and the relationship between dark matter hosts and substructures, are based on a high-resolution cosmological simulation, the Bolshoi simulation. We associate galaxies with dark matter halos and subhalos using subhalo abundance matching, and perform a comprehensive analysis which investigates the underlying assumptions of this technique including (a) which halo property is most closely associated with galaxy stellar masses and luminosities, (b) how much scatter is in this relationship, and (c) how much subhalos can be stripped before their galaxies are destroyed. The models are jointly constrained by new measurements of the projected two-point galaxy clustering and the observed conditional stellar mass function of galaxies in groups. We find that an abundance matching model that associates galaxies with the peak circular velocity of their halos is in good agreement with the data, when scatter of 0.20 {+-} 0.03 dex in stellar mass at a given peak velocity is included. This confirms the theoretical …
Date: July 11, 2012
Creator: Reddick, Rachel M.; Wechsler, Risa H.; Tinker, Jeremy L. & Behroozi, Peter S.
System: The UNT Digital Library
Measurement of the Auger Parameter and Wagner Plot for Uranium Compounds (open access)

Measurement of the Auger Parameter and Wagner Plot for Uranium Compounds

None
Date: September 11, 2012
Creator: Holliday, K S; Siekhaus, W & Nelson, A J
System: The UNT Digital Library
Ray-tracing tutorial (open access)

Ray-tracing tutorial

N/A
Date: November 11, 2012
Creator: F., Meot
System: The UNT Digital Library
Extinction and ecological retreat in a community of primates (open access)

Extinction and ecological retreat in a community of primates

None
Date: May 11, 2012
Creator: Crowley, B. E.; Godfrey, L. R.; Guilderson, T. P.; Zermeno, P.; Koch, P. L. & Dominy, N.
System: The UNT Digital Library
Steam Reforming on Transition-metal Carbides from Density-functional Theory (open access)

Steam Reforming on Transition-metal Carbides from Density-functional Theory

A screening study of the steam reforming reaction on clean and oxygen covered early transition-metal carbides surfaces is performed by means of density-functional theory calculations. It is found that carbides provide a wide spectrum of reactivities, from too reactive via suitable to too inert. Several molybdenum-based systems are identified as possible steam reforming catalysts. The findings suggest that carbides provide a playground for reactivity tuning, comparable to the one for pure metals.
Date: May 11, 2012
Creator: Vojvodic, Aleksandra
System: The UNT Digital Library
DOE-NNSA Domestic and International Security Training (open access)

DOE-NNSA Domestic and International Security Training

None
Date: October 11, 2012
Creator: O'Brien, M.
System: The UNT Digital Library
Physical Protection at Non-Reactor Facilities (open access)

Physical Protection at Non-Reactor Facilities

None
Date: October 11, 2012
Creator: O'Brien, M
System: The UNT Digital Library
Full Toroidal Imaging of Non-axisymmetric Plasma Material Interaction in the National Spherical Torus eXperiment (open access)

Full Toroidal Imaging of Non-axisymmetric Plasma Material Interaction in the National Spherical Torus eXperiment

A pair of two dimensional fast cameras with a wide angle view (allowing a full radial and toroidal coverage of the lower divertor) was installed in the National Spherical Torus Experiment in order to monitor non-axisymmetric effects. A custom polar remapping procedure and an absolute photometric calibration enabled the easier visualization and quantitative analysis of non-axisymmetric plasma material interaction (e.g., strike point splitting due to application of 3D fields and effects of toroidally asymmetric plasma facing components).
Date: July 11, 2012
Creator: Filippo Scotti, A.L. Roquemore, and V. A. Soukhanovskii
System: The UNT Digital Library
Accelerators for Intensity Frontier Research (open access)

Accelerators for Intensity Frontier Research

In 2008, the Particle Physics Project Prioritization Panel identified three frontiers for research in high energy physics, the Energy Frontier, the Intensity Frontier, and the Cosmic Frontier. In this paper, I will describe how Fermilab is configuring and upgrading the accelerator complex, prior to the development of Project X, in support of the Intensity Frontier.
Date: May 11, 2012
Creator: Derwent, Paul
System: The UNT Digital Library
Kinetic theory and Vlasov simulation of nonlinear ion acoustic waves in multi-ion species plasmas (open access)

Kinetic theory and Vlasov simulation of nonlinear ion acoustic waves in multi-ion species plasmas

None
Date: December 11, 2012
Creator: Chapman, T. D.; Berger, R. L.; Brunner, S. & Williams, E. A.
System: The UNT Digital Library
Comparison of LHC and ILC Capabilities for Higgs Boson Coupling Measurements (open access)

Comparison of LHC and ILC Capabilities for Higgs Boson Coupling Measurements

I estimate the accuracies on Higgs boson coupling constants that experiments at the Large Hadron Collider and the International Linear Collider are capable of reaching over the long term.
Date: July 11, 2012
Creator: Peskin, Michael E.
System: The UNT Digital Library
APPLICATION FO FLOW FORMING FOR USE IN RADIOACTIVE MATERIAL PACKAGING DESIGNS (open access)

APPLICATION FO FLOW FORMING FOR USE IN RADIOACTIVE MATERIAL PACKAGING DESIGNS

This paper reports on the development and testing performed to demonstrate the use of flow forming as an alternate method of manufacturing containment vessels for use in radioactive material shipping packaging designs. Additionally, ASME Boiler and Pressure Vessel Code, Section III, Subsection NB compliance along with the benefits compared to typical welding of containment vessels will be discussed. SRNL has completed fabrication development and the testing on flow formed containment vessels to demonstrate the use of flow forming as an alternate method of manufacturing a welded 6-inch diameter containment vessel currently used in the 9975 and 9977 radioactive material shipping packaging. Material testing and nondestructive evaluation of the flow formed parts demonstrate compliance to the minimum material requirements specified in applicable parts of ASME Boiler and Pressure Vessel Code, Section II. Destructive burst testing shows comparable results to that of a welded design. The benefits of flow forming as compared to typical welding of containment vessels are significant: dimensional control is improved due to no weld distortion; less final machining; weld fit-up issues associated with pipes and pipe caps are eliminated; post-weld non-destructive testing (i.e., radiography and die penetrant tests) is not necessary; and less fabrication steps are required. Results …
Date: July 11, 2012
Creator: Blanton, P.; Eberl, K. & Abramczyk, G.
System: The UNT Digital Library
Advanced divertor configurations with large flux expansion. (open access)

Advanced divertor configurations with large flux expansion.

None
Date: June 11, 2012
Creator: et. al, V
System: The UNT Digital Library
Modular Aneutronic Fusion Engine (open access)

Modular Aneutronic Fusion Engine

NASA's JUNO mission will arrive at Jupiter in July 2016, after nearly five years in space. Since operational costs tend to rise with mission time, minimizing such times becomes a top priority. We present the conceptual design for a 10MW aneutronic fusion engine with high exhaust velocities that would reduce transit time for a Jupiter mission to eighteen months and enable more challenging exploration missions in the solar system and beyond. __________________________________________________
Date: May 11, 2012
Creator: Pajer, Gary; Razin, Yosef; Paluszek, Michael; Glasser, A. H. & Cohen, Samuel
System: The UNT Digital Library
Optimization for Single-Spike X-Ray FELs at LCLS with a Low Charge Beam (open access)

Optimization for Single-Spike X-Ray FELs at LCLS with a Low Charge Beam

None
Date: December 11, 2012
Creator: Wang, L.
System: The UNT Digital Library
Markov Model of Accident Progression at Fukushima Daiichi (open access)

Markov Model of Accident Progression at Fukushima Daiichi

On March 11, 2011, a magnitude 9.0 earthquake followed by a tsunami caused loss of offsite power and disabled the emergency diesel generators, leading to a prolonged station blackout at the Fukushima Daiichi site. After successful reactor trip for all operating reactors, the inability to remove decay heat over an extended period led to boil-off of the water inventory and fuel uncovery in Units 1-3. A significant amount of metal-water reaction occurred, as evidenced by the quantities of hydrogen generated that led to hydrogen explosions in the auxiliary buildings of the Units 1 & 3, and in the de-fuelled Unit 4. Although it was assumed that extensive fuel damage, including fuel melting, slumping, and relocation was likely to have occurred in the core of the affected reactors, the status of the fuel, vessel, and drywell was uncertain. To understand the possible evolution of the accident conditions at Fukushima Daiichi, a Markov model of the likely state of one of the reactors was constructed and executed under different assumptions regarding system performance and reliability. The Markov approach was selected for several reasons: It is a probabilistic model that provides flexibility in scenario construction and incorporates time dependence of different model states. …
Date: November 11, 2012
Creator: Cuadra, A.; Bari, R.; Cheng, L. Y.; Ginsberg, T.; Lehner, J.; Martinez-Guridi, G. et al.
System: The UNT Digital Library
NEAR INFRARED REFLECTANCE SPECTROSCOPY AS A PROCESS SIGNATURE IN URANIUM OXIDES (open access)

NEAR INFRARED REFLECTANCE SPECTROSCOPY AS A PROCESS SIGNATURE IN URANIUM OXIDES

None
Date: March 11, 2012
Creator: Plaue, J W; Klunder, G L; Czerwinski, K R & Hutcheon, I D
System: The UNT Digital Library
Interplay between intrinsic and stacking-fault magnetic domains in bi-layered manganites (open access)

Interplay between intrinsic and stacking-fault magnetic domains in bi-layered manganites

We present a low temperature X-ray photoemission electron microscopy study of the bi-layered manganite compound La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7} (BL-LSMO) to investigate the influence of stacking faults, which are structurally and magnetically different from the bi-layered host. In BL-LSMO small magnetic moment persists to T* = 300K, well above the Curie temperature of 120K (T{sub C}). Our magnetic images show that 3D stacking faults are responsible for the T* transition. Furthermore, close to the T{sub C}, stacking faults are well coupled to the bi-layered host with latter magnetic domains controlling the spin direction of the stacking faults. Contrary to recent reports, we find that stacking faults do not seed magnetic domains in the host via an exchange spring mechanism and the intrinsic T{sub C} of the BL-LSMO is not lower than 120K.
Date: September 11, 2012
Creator: Hossain, M. A; Burkhardt, Mark H.; Sarkar, S.; Ohldag, H.; Chuang, Y. D.; Scholl, A. et al.
System: The UNT Digital Library
NANOFLUIDICS REVOLUTION: PROTECTING THE WORLD ONE DROP AT A TIME (open access)

NANOFLUIDICS REVOLUTION: PROTECTING THE WORLD ONE DROP AT A TIME

Nanofluidics is a technology that involves the transport of very small liquid samples, on the order of micro- or pico-liters, confined to nanoscale structures. Scientists at the Savannah River National Laboratory (SRNL) in collaboration with the University of South Carolina are investigating a new measurement technique using nanofluidics for fast and easy verification of the presence of special nuclear material (SNM) in aqueous solutions. Research is specifically geared toward developing small-footprint high sensitivity lab-on-a-chip devices for the detection and separation of plutonium. It also laid the groundwork for developing ultra-sensitive sensors using in structural health monitoring system for in situ, noninterrupted detection of the leaching and migration of radionuclides outside the cementitious barriers for nuclear waste storage facilities. This innovative method has promise for the nuclear industry's processing technologies, environmental protection, and safeguards.
Date: September 11, 2012
Creator: Mendez-Torres, A.; Lam, P.; Bronikowski, M.; Gaillard, J.; Wade, E.; Wang, G. et al.
System: The UNT Digital Library
LHC Abort Gap Cleaning Studies During Luminosity Operation (open access)

LHC Abort Gap Cleaning Studies During Luminosity Operation

The presence of significant intensities of un-bunched beam is a potentially serious issue in the LHC. Procedures using damper kickers for cleaning both the Abort Gap (AG) and the buckets targeted for injection, are currently in operation at flat bottom. Recent observations of relatively high population of the AG during physics runs brought up the need for AG cleaning during luminosity operation. In this paper the results of experimental studies performed in October 2011 are presented.
Date: May 11, 2012
Creator: Gianfelice-Wendt, E.; Bartmann, W.; Boccardi, A.; Bracco, C.; Bravin, E.; Goddard, B. et al.
System: The UNT Digital Library
Corrosion Testing of Carbon Steel in Oxalic Acid that Contains Dissolved Iron (open access)

Corrosion Testing of Carbon Steel in Oxalic Acid that Contains Dissolved Iron

Radioactive liquid waste has been stored in underground carbon steel tanks for nearly 60 years at the Savannah River Site. The site is currently in the process of removing the waste from these tanks in order to place it into vitrified, stable state for longer term storage. The last stage in the removal sequence is a chemical cleaning step that breaks up and dissolves metal oxide solids that cannot be easily pumped out of the tank. Oxalic acid (OA) will be used to chemically clean the tanks after waste retrieval is completed. The waste tanks at SRS were constructed from carbon steel materials and thus are vulnerable to corrosion in acidic media. In addition to structural impacts, the impact of corrosion on the hydrogen generated during the process must be assessed. Electrochemical and coupon immersion tests were used to investigate the corrosion mechanism at anticipated process conditions. The testing showed that the corrosion rates were dependent upon the reduction of the iron species that had dissolved in solution. Initial corrosion rates were elevated due to the reduction of the ferric species to ferrous species. At later times, as the ferric species depleted, the corrosion rate decreased. On the other hand, …
Date: October 11, 2012
Creator: Wiersma, Bruce J.; Mickalonis, John I. & Subramanian, Karthik H.
System: The UNT Digital Library