SYNTHESIS AND CHARACTERIZATION OF PROTON CONDUCTORS (open access)

SYNTHESIS AND CHARACTERIZATION OF PROTON CONDUCTORS

The morphological and electrical properties of yttrium (Y) and indium (In) doped barium cerate perovskites of the form BaIn{sub 0.3-x}Y{sub x}Ce{sub 0.7}O{sub 3-{delta}} (with x=0-0.3) prepared by a modified Pechini method were investigated as potential high temperature proton conductors with improved chemical stability. The sinterability increased with the increase of In-doping, and the perovskite phase was found in the BaIn{sub 0.3-x}Y{sub x}Ce{sub 0.7}O{sub 3-{delta}} solid solutions over the range 0 {le} x {le} 0.3. The conductivities decreased (from x to x, insert quantitative values) while the tolerance to wet CO{sub 2} improved for BaIn{sub 0.3-x}Y{sub x}Ce{sub 0.7}O{sub 3-{delta}} samples with an increase of In-doping.
Date: February 18, 2010
Creator: Brinkman, K.
Object Type: Article
System: The UNT Digital Library
3D Surface Mapping of Capsule Fill-Tube Assemblies used in Laser-Driven Fusion Targets (open access)

3D Surface Mapping of Capsule Fill-Tube Assemblies used in Laser-Driven Fusion Targets

This paper presents the development of a 3D surface mapping system used to measure the surface of a fusion target Capsule Fill-Tube Assembly (CFTA). The CFTA consists of a hollow Ge-doped plastic sphere, called a capsule, ranging in outer diameter between 2.2 mm and 2.6 mm and an attached 150 {micro}m diameter glass-core fill-tube that tapers down to a 10{micro} diameter at the capsule. The mapping system is an enabling technology to facilitate a quality assurance program and to archive 3D surface information of each capsule used in fusion ignition experiments that are currently being performed at the National Ignition Facility (NIF). The 3D Surface Mapping System is designed to locate and quantify surface features with a height of 50 nm and 300 nm in width or larger. Additionally, the system will be calibrated such that the 3D measured surface can be related to the capsule surface angular coordinate system to within 0.25 degree (1{sigma}), which corresponds to approximately 5 {micro}m linear error on the capsule surface.
Date: February 18, 2011
Creator: Buice, E. S.; Alger, E. T.; Antipa, N. A.; Bhandarkar, S. D.; Biesiada, T. A.; Conder, A. D. et al.
Object Type: Article
System: The UNT Digital Library
Building Cryogenic Targets with a Precision Reconfigurable Assembly Station (open access)

Building Cryogenic Targets with a Precision Reconfigurable Assembly Station

None
Date: February 18, 2010
Creator: Castro, C; Montesanti, R C; Taylor, J S; Hamza, A V; Dzenitis, E G; Alger, E T et al.
Object Type: Article
System: The UNT Digital Library
Initial Assessment of Electron and X-Ray Production and Charge Exchange in the NDCX-II Accelerator (open access)

Initial Assessment of Electron and X-Ray Production and Charge Exchange in the NDCX-II Accelerator

The purpose of this note is to provide initial assessments of some atomic physics effects for the accelerator section of NDCX-II. There are several effects we address: the production of electrons associated with loss of beam ions to the walls, the production of electrons associated with ionization of background gas, the possibly resultant production of X-rays when these electrons hit bounding surfaces, and charge exchange of beam ions on background gas. The results presented here are based on a number of caveats that will be stated below, which we will attempt to remove in the near future.
Date: February 18, 2010
Creator: Cohen, R. H.
Object Type: Report
System: The UNT Digital Library
Simulations of NSTX with a Liquid Lithium Divertor Module (open access)

Simulations of NSTX with a Liquid Lithium Divertor Module

A strategy to develop self-consistent simulations of the behavior of lithium in the Liquid Lithium Divertor (LLD) module to be installed in NSTX is described. In this initial stage of the plan, the UEDGE edge plasma transport code is used to simulate an existing NSTX shot, with UEDGE's transport coefficients set using midplane and divertor diagnostic data. The LLD is incorporated into the simulations as a reduction in the recycling coefficient over the outer divertor. Heat transfer calculations performed using the resulting heat flux profiles provide preliminary estimates on operating limits for the LLD as well as input data for subsequent steps in the LLD modeling effort.
Date: February 18, 2010
Creator: D.P. Stotler, R. Maingi, L.E. Zakharov, H.W. Kugel, A. Yu. Pigarov, T.D. Rognlien, and V.A. Soukhanovskii
Object Type: Report
System: The UNT Digital Library
Improvements to Nuclear Data and Its Uncertainties by Theoretical Modeling (open access)

Improvements to Nuclear Data and Its Uncertainties by Theoretical Modeling

This project addresses three important gaps in existing evaluated nuclear data libraries that represent a significant hindrance against highly advanced modeling and simulation capabilities for the Advanced Fuel Cycle Initiative (AFCI). This project will: Develop advanced theoretical tools to compute prompt fission neutrons and gamma-ray characteristics well beyond average spectra and multiplicity, and produce new evaluated files of U and Pu isotopes, along with some minor actinides; Perform state-of-the-art fission cross-section modeling and calculations using global and microscopic model input parameters, leading to truly predictive fission cross-sections capabilities. Consistent calculations for a suite of Pu isotopes will be performed; Implement innovative data assimilation tools, which will reflect the nuclear data evaluation process much more accurately, and lead to a new generation of uncertainty quantification files. New covariance matrices will be obtained for Pu isotopes and compared to existing ones. The deployment of a fleet of safe and efficient advanced reactors that minimize radiotoxic waste and are proliferation-resistant is a clear and ambitious goal of AFCI. While in the past the design, construction and operation of a reactor were supported through empirical trials, this new phase in nuclear energy production is expected to rely heavily on advanced modeling and simulation capabilities. …
Date: February 18, 2013
Creator: Danon, Yaron; Nazarewicz, Witold & Talou, Patrick
Object Type: Report
System: The UNT Digital Library
Material Design, Selection, and Manufacturing Methods for System Sustainment (open access)

Material Design, Selection, and Manufacturing Methods for System Sustainment

This paper describes a material selection and validation process proven to be successful for manufacturing high-reliability long-life product. The National Secure Manufacturing Center business unit of the Kansas City Plant (herein called KCP) designs and manufactures complex electrical and mechanical components used in extreme environments. The material manufacturing heritage is founded in the systems design to manufacturing practices that support the U.S. Department of Energy’s National Nuclear Security Administration (DOE/NNSA). Material Engineers at KCP work with the systems designers to recommend materials, develop test methods, perform analytical analysis of test data, define cradle to grave needs, present final selection and fielding. The KCP material engineers typically will maintain cost control by utilizing commercial products when possible, but have the resources and to develop and produce unique formulations as necessary. This approach is currently being used to mature technologies to manufacture materials with improved characteristics using nano-composite filler materials that will enhance system design and production. For some products the engineers plan and carry out science-based life-cycle material surveillance processes. Recent examples of the approach include refurbished manufacturing of the high voltage power supplies for cockpit displays in operational aircraft; dry film lubricant application to improve bearing life for guided munitions …
Date: February 18, 2010
Creator: David Sowder, Jim Lula, Curtis Marshall
Object Type: Article
System: The UNT Digital Library
TRISO-Fuel Element Performance Modeling for the Hybrid LIFE Engine with Pu Fuel Blanket (open access)

TRISO-Fuel Element Performance Modeling for the Hybrid LIFE Engine with Pu Fuel Blanket

A TRISO-coated fuel thermo-mechanical performance study is performed for the hybrid LIFE engine to test the viability of TRISO particles to achieve ultra-high burnup of a weapons-grade Pu blanket. Our methodology includes full elastic anisotropy, time and temperature varying material properties for all TRISO layers, and a procedure to remap the elastic solutions in order to achieve fast fluences up to 30 x 10{sup 25} n {center_dot} m{sup -2} (E > 0.18 MeV). In order to model fast fluences in the range of {approx} 7 {approx} 30 x 10{sup 25} n {center_dot} m{sup -2}, for which no data exist, careful scalings and extrapolations of the known TRISO material properties are carried out under a number of potential scenarios. A number of findings can be extracted from our study. First, failure of the internal pyrolytic carbon (PyC) layer occurs within the first two months of operation. Then, the particles behave as BISO-coated particles, with the internal pressure being withstood directly by the SiC layer. Later, after 1.6 years, the remaining PyC crumbles due to void swelling and the fuel particle becomes a single-SiC-layer particle. Unrestrained by the PyC layers, and at the temperatures and fluences in the LIFE engine, the SiC …
Date: February 18, 2010
Creator: DeMange, P.; Marian, J.; Caro, M. & Caro, A.
Object Type: Article
System: The UNT Digital Library
A grazing incidence x-ray streak camera for ultrafast, single-shot measurements (open access)

A grazing incidence x-ray streak camera for ultrafast, single-shot measurements

An ultrafast x-ray streak camera has been realized using a grazing incidence reflection photocathode. X-rays are incident on a gold photocathode at a grazing angle of 20 degree and photoemitted electrons are focused by a large aperture magnetic solenoid lens. The streak camera has high quantum efficiency, 600fs temporal resolution, and 6mm imaging length in the spectral direction. Its single shot capability eliminates temporal smearing due to sweep jitter, and allows recording of the ultrafast dynamics of samples that undergo non-reversible changes.
Date: February 18, 2010
Creator: Feng, Jun; Engelhorn, K.; Cho, B.I.; Lee, H. J.; Greaves, M.; Weber, C. P. et al.
Object Type: Article
System: The UNT Digital Library
Uranium Anodic Dissolution under Slightly Alkaline Conditions Progress Report Full-Scale Demonstration with DU Foil (open access)

Uranium Anodic Dissolution under Slightly Alkaline Conditions Progress Report Full-Scale Demonstration with DU Foil

None
Date: February 18, 2014
Creator: Gelis, A.; Brown, M.A.; Wiedmeyer, S. & Vandegrift, G.F. (Chemical Sciences and Engineering Division)
Object Type: Report
System: The UNT Digital Library
Proliferation Resistant Nuclear Reactor Fuel (open access)

Proliferation Resistant Nuclear Reactor Fuel

Global appetite for fission power is projected to grow dramatically this century, and for good reason. Despite considerable research to identify new sources of energy, fission remains the most plentiful and practical alternative to fossil fuels. The environmental challenges of fossil fuel have made the fission power option increasingly attractive, particularly as we are forced to rely on reserves in ecologically fragile or politically unstable corners of the globe. Caught between a globally eroding fossil fuel reserve as well as the uncertainty and considerable costs in the development of fusion power, most of the world will most likely come to rely on fission power for at least the remainder of the 21st century. Despite inevitable growth, fission power faces enduring challenges in sustainability and security. One of fission power's greatest hurdles to universal acceptance is the risk of potential misuse for nefarious purposes of fissionable byproducts in spent fuel, such as plutonium. With this issue in mind, we have discussed intrinsic concepts in this report that are motivated by the premise that the utility, desirability, and applicability of nuclear materials can be reduced. In a general sense, the intrinsic solutions aim to reduce or eliminate the quantity of existing weapons …
Date: February 18, 2011
Creator: Gray, L W; Moody, K J; Bradley, K S & Lorenzana, H E
Object Type: Report
System: The UNT Digital Library
Niche of harmful alga Aureococcus anophagefferens revealed through ecogenomics (open access)

Niche of harmful alga Aureococcus anophagefferens revealed through ecogenomics

Harmful algal blooms (HABs) cause significant economic and ecological damage worldwide. Despite considerable efforts, a comprehensive understanding of the factors that promote these blooms has been lacking, because the biochemical pathways that facilitate their dominance relative to other phytoplankton within specific environments have not been identified. Here, biogeochemical measurements showed that the harmful alga Aureococcus anophagefferens outcompeted co-occurring phytoplankton in estuaries with elevated levels of dissolved organic matter and turbidity and low levels of dissolved inorganic nitrogen. We subsequently sequenced the genome of A. anophagefferens and compared its gene complement with those of six competing phytoplankton species identified through metaproteomics. Using an ecogenomic approach, we specifically focused on gene sets that may facilitate dominance within the environmental conditions present during blooms. A. anophagefferens possesses a larger genome (56 Mbp) and has more genes involved in light harvesting, organic carbon and nitrogen use, and encoding selenium- and metal-requiring enzymes than competing phytoplankton. Genes for the synthesis of microbial deterrents likely permit the proliferation of this species, with reduced mortality losses during blooms. Collectively, these findings suggest that anthropogenic activities resulting in elevated levels of turbidity, organic matter, and metals have opened a niche within coastal ecosystems that ideally suits the unique …
Date: February 18, 2011
Creator: Grigoriev, Igor; Gobler, Christopher; Salamov, Asaf; Kuo, Alan; Terry, Astrid; Pangillian, Jasmyn et al.
Object Type: Article
System: The UNT Digital Library
Electrodeposition of Uranium and Plutonium on Thin Carbon and Titanium Substrates (open access)

Electrodeposition of Uranium and Plutonium on Thin Carbon and Titanium Substrates

Preparation of Pu and U targets on thin natural C (100 {micro}g/cm{sup 2}) and ti (2 and 3 {micro}m) substrates is described. The Actinide material of interest was first purified using ion exchange chromatography to remove any matrix contaminants or decay products present in the parent stock solution. The actinide solution was prepared in 0.05 M HNO{sub 3} with a final aliquot volume not exceeding 100 {micro}L for the deposition procedure. The electroplating cells were developed in-house and were primarily made of Teflon. The source material deposited ranged from 125 to 400 {micro}g/cm{sup 2}. It was determined that multiple layers of U and Pu were required to produce thicker targets on Ti. Plating efficiency was greatly affected by the cell volume, solution aliquot size, pre-treatment of the foils, solution mixing during palting, and the fit of the electrode contact with the target substrate. The final procedure used for deposition is described in detail.
Date: February 18, 2011
Creator: Henderson, R A; Gostic, J M; Burke, J T; Fisher, S E & Wu, C Y
Object Type: Article
System: The UNT Digital Library
Mechanism of Thermal Reversal of the (Fulvalene)tetracarbonyldiruthenium Photoisomerization: Toward Molecular Solar-Thermal Energy Storage (open access)

Mechanism of Thermal Reversal of the (Fulvalene)tetracarbonyldiruthenium Photoisomerization: Toward Molecular Solar-Thermal Energy Storage

In the currently intensifying quest to harness solar energy for the powering of our planet, most efforts are centered around photoinduced generic charge separation, such as in photovoltaics, water splitting, other small molecule activation, and biologically inspired photosynthetic systems. In contrast, direct collection of heat from sunlight has received much less diversified attention, its bulk devoted to the development of concentrating solar thermal power plants, in which mirrors are used to focus the sun beam on an appropriate heat transfer material. An attractive alternative strategy would be to trap solar energy in the form of chemical bonds, ideally through the photoconversion of a suitable molecule to a higher energy isomer, which, in turn, would release the stored energy by thermal reversal. Such a system would encompass the essential elements of a rechargeable heat battery, with its inherent advantages of storage, transportability, and use on demand. The underlying concept has been explored extensively with organic molecules (such as the norbornadiene-quadricyclane cycle), often in the context of developing photoswitches. On the other hand, organometallic complexes have remained relatively obscure in this capacity, despite a number of advantages, including expanded structural tunability and generally favorable electronic absorption regimes. A highly promising organometallic system …
Date: February 18, 2010
Creator: Kanai, Y; Srinivasan, V; Meier, S K; Vollhardt, K P & Grossman, J C
Object Type: Article
System: The UNT Digital Library
Final Report: AST-0613577 "Experimental study of magnetic bubble expansion as a model for extragalactic radio lobes" (open access)

Final Report: AST-0613577 "Experimental study of magnetic bubble expansion as a model for extragalactic radio lobes"

Final report for project "Experimental study of magnetic bubble expansion as a model for extragalactic radio lobes" supported by NSF/DOE Joint Program in Basic Plasma Science.
Date: February 18, 2011
Creator: Lynn, Alan
Object Type: Report
System: The UNT Digital Library
Fabrication and Test of the NIF Cryogenic Target System (open access)

Fabrication and Test of the NIF Cryogenic Target System

None
Date: February 18, 2010
Creator: Malsbury, T N; Atkinson, D P; Brugman, V P; Coffield, F E; Deis, G A; Edwards, O D et al.
Object Type: Article
System: The UNT Digital Library
Impact response of US Army and National Football League helmet pad systems (open access)

Impact response of US Army and National Football League helmet pad systems

Lawrence Livermore National Laboratory [LLNL] was tasked to compare the impact response of NFL helmet pad systems and U.S. Army pad systems compatible with an Advanced Combat Helmet [ACH] at impact velocities up to 20 ft/s. This was a one-year study funded by the U.S. Army and JIEDDO. The Army/JIEDDO point of contact is COL R. Todd Dombroski, DO, JIEDDO Surgeon. LLNL was chosen by committee to perform the research based on prior published computational studies of the mechanical response of helmets and skulls to blast. Our collaborators include the U.S. Army Aeromedical Research Laboratory [USAARL] (a DoD laboratory responsible for impact testing helmets), Team Wendy and Oregon Aero (current and former ACH pad manufacturers), Riddell and Xenith (NFL pad manufacturers), and d3o (general purpose sports pad manufacturer). The manufacturer-supplied pad systems that were studied are shown in the figure below. The first two are the Army systems, which are bilayer foam pads with both hard and soft foam and a water-resistant airtight wrapper (Team Wendy) or a water-resistant airtight coating (Oregon Aero). The next two are NFL pad systems. The Xenith system consists of a thin foam pad and a hollow air-filled cylinder that elastically buckles under load. The …
Date: February 18, 2011
Creator: Moss, W C & King, M J
Object Type: Report
System: The UNT Digital Library
30th Anniversary Symposium of the US/Japan Collaboration in High Energy Physics (open access)

30th Anniversary Symposium of the US/Japan Collaboration in High Energy Physics

Proceedings of the Symposium that celebrated the 30th Anniversary of the US/Japan Collaboration in High Energy Physics
Date: February 18, 2011
Creator: Ozaki, S.
Object Type: Report
System: The UNT Digital Library
Noise Properties of Rectifying Nanopores (open access)

Noise Properties of Rectifying Nanopores

Ion currents through three types of rectifying nanoporous structures are studied and compared for the first time: conically shaped polymer nanopores, glass nanopipettes, and silicon nitride nanopores. Time signals of ion currents are analyzed by power spectrum. We focus on the low-frequency range where the power spectrum magnitude scales with frequency, f, as 1/f. Glass nanopipettes and polymer nanopores exhibit non-equilibrium 1/f noise, thus the normalized power spectrum depends on the voltage polarity and magnitude. In contrast, 1/f noise in rectifying silicon nitride nanopores is of equilibrium character. Various mechanisms underlying the voltage-dependent 1/f noise are explored and discussed, including intrinsic pore wall dynamics, and formation of vortices and non-linear flow patterns in the pore. Experimental data are supported by modeling of ion currents based on the coupled Poisson-Nernst-Planck and Navier Stokes equations. We conclude that the voltage-dependent 1/f noise observed in polymer and glass asymmetric nanopores might result from high and asymmetric electric fields inducing secondary effects in the pore such as enhanced water dissociation.
Date: February 18, 2011
Creator: Powell, M. R.; Sa, N.; Davenport, M.; Healy, K.; Vlassiouk, I.; Letant, S. E. et al.
Object Type: Article
System: The UNT Digital Library
The FSP Boundary Science Driver Plan (open access)

The FSP Boundary Science Driver Plan

None
Date: February 18, 2011
Creator: Rognlien, T. D.; Whyte, D. G.; Brooks, J. N.; Canik, J. M.; Greenwald, M.; Stotler, D. P. et al.
Object Type: Report
System: The UNT Digital Library
Manufacturing Ultra-Precision Meso-scale Products by Coining (open access)

Manufacturing Ultra-Precision Meso-scale Products by Coining

A method for replicating ultra-precision, meso-scale features onto a near-net-shape metallic blank has been demonstrated. The 'coining' technology can be used to imprint a wide range of features and/or profiles into two opposing surfaces. The instrumented system provides the ability to measure and control the product thickness and total thickness variation (TTV). The coining mechanism relies on kinematic principles to accurately and efficiently produce ultra-precision work pieces without the production of by products such as machining chips, or grinding swarf while preserving surface finish, material structure and overall form. Coining has been developed as a niche process for manufacturing difficult to machine, millimeter size components made from materials that may present hazardous conditions. In the case described in this paper a refractory metal part, tantalum (Ta) was produced with 4 {micro}m peak to valley 50 {micro}m special wavelength sine wave coined into the surface of 50 {micro}m blank. This technique shows promise for use on ductile materials that cannot be precision machined with conventional single crystal diamond tooling and/or has strict requirements on subsurface damage, surface impurities and grain structure. As a production process, it can be used to reduce manufacturing costs where large numbers of ultra-precision, repetitive designs are …
Date: February 18, 2010
Creator: Seugling, R M; Davis, P J; Rickens, K; Osmer, J & Brinksmeier, E
Object Type: Article
System: The UNT Digital Library
Water Chemistry Control System for Recovery of Damaged and Degraded Spent Fuel (open access)

Water Chemistry Control System for Recovery of Damaged and Degraded Spent Fuel

The International Atomic Energy Agency (IAEA) and the government of Serbia have led the project cosponsored by the U.S, Russia, European Commission, and others to repackage and repatriate approximately 8000 spent fuel elements from the RA reactor fuel storage basins at the VIN?A Institute of Nuclear Sciences to Russia for reprocessing. The repackaging and transportation activities were implemented by a Russian consortium which includes the Sosny Company, Tekhsnabeksport (TENEX) and Mayak Production Association. High activity of the water of the fuel storage basin posed serious risk and challenges to the fuel removal from storage containers and repackaging for transportation. The risk centered on personnel exposure, even above the basin water, due to the high water activity levels caused by Cs-137 leached from fuel elements with failed cladding. A team of engineers from the U.S. DOE-NNSA's Global Threat Reduction Initiative, the Vinca Institute, and the IAEA performed the design, development, and deployment of a compact underwater water chemistry control system (WCCS) to remove the Cs-137 from the basin water and enable personnel safety above the basin water for repackaging operations. Key elements of the WCCS system included filters, multiple columns containing an inorganic sorbent, submersible pumps and flow meters. All system …
Date: February 18, 2011
Creator: Sindelar, R.; Fisher, D. & Thomas, J.
Object Type: Article
System: The UNT Digital Library
REGULATORY ISSUES ASSOCIATED WITH SHIPMENT OF SMALL QUANTITIES OF RADIOACTIVE MATERIAL (open access)

REGULATORY ISSUES ASSOCIATED WITH SHIPMENT OF SMALL QUANTITIES OF RADIOACTIVE MATERIAL

None
Date: February 18, 2010
Creator: Smith, A.; Abramczyk, G. & Nathan, S.
Object Type: Article
System: The UNT Digital Library
Phenotypic transition maps of 3D breast acini obtained by imaging-guided agent-based modeling (open access)

Phenotypic transition maps of 3D breast acini obtained by imaging-guided agent-based modeling

We introduce an agent-based model of epithelial cell morphogenesis to explore the complex interplay between apoptosis, proliferation, and polarization. By varying the activity levels of these mechanisms we derived phenotypic transition maps of normal and aberrant morphogenesis. These maps identify homeostatic ranges and morphologic stability conditions. The agent-based model was parameterized and validated using novel high-content image analysis of mammary acini morphogenesis in vitro with focus on time-dependent cell densities, proliferation and death rates, as well as acini morphologies. Model simulations reveal apoptosis being necessary and sufficient for initiating lumen formation, but cell polarization being the pivotal mechanism for maintaining physiological epithelium morphology and acini sphericity. Furthermore, simulations highlight that acinus growth arrest in normal acini can be achieved by controlling the fraction of proliferating cells. Interestingly, our simulations reveal a synergism between polarization and apoptosis in enhancing growth arrest. After validating the model with experimental data from a normal human breast line (MCF10A), the system was challenged to predict the growth of MCF10A where AKT-1 was overexpressed, leading to reduced apoptosis. As previously reported, this led to non growth-arrested acini, with very large sizes and partially filled lumen. However, surprisingly, image analysis revealed a much lower nuclear density than …
Date: February 18, 2011
Creator: Tang, Jonathan; Enderling, Heiko; Becker-Weimann, Sabine; Pham, Christopher; Polyzos, Aris; Chen, Chen-Yi et al.
Object Type: Article
System: The UNT Digital Library