Raman Spectroscopy of UH3 from the Hydrogen Corrosion of Uranium (open access)

Raman Spectroscopy of UH3 from the Hydrogen Corrosion of Uranium

Hydrogen reacts with a uranium surface to form a fine, pyrophoric metal power (UH{sub 3}). Few spectroscopic studies have been conducted to study this reaction. Advances in Raman spectroscopy permit the application of the Raman method to formally difficult areas of chemistry such as the hydrogen corrosion of uranium: availability of multiple laser excitation wavelengths; fiber optics delivery and collection systems; upgraded instrumentation and detection techniques; and development of special enclosed in situ reactor cells. UH{sub 3} vibrations are expected to occur at low frequencies due to extended U-H-U structure.
Date: May 31, 2011
Creator: Smyrl, N. R.; Stowe, A. C. & Powell, G. L.
System: The UNT Digital Library
Characterization of Mo/Si multilayer growth on stepped topographies (open access)

Characterization of Mo/Si multilayer growth on stepped topographies

Mo/Si multilayer mirrors with nanoscale bilayer thicknesses have been deposited on stepped substrate topographies, using various deposition angles. The multilayer morphology at the stepedge region was studied by cross section transmission electron microscopy. A transition from a continuous- to columnar layer morphology is observed near the step-edge, as a function of the local angle of incidence of the deposition flux. Taking into account the corresponding kinetics and anisotropy in layer growth, a continuum model has been developed to give a detailed description of the height profiles of the individual continuous layers. Complementary optical characterization of the multilayer system using a microscope operating in the extreme ultraviolet wavelength range, revealed that the influence of the step-edge on the planar multilayer structure is restricted to a region within 300 nm from the step-edge.
Date: August 31, 2011
Creator: van den Boogaard, A. J. R.; Louis, E.; Zoethout, E.; Goldberg, K. A. & Bijkerk, F.
System: The UNT Digital Library
B0 Meson Decays to Rho0 K*0, F0 K*0, And Rho- K* , Including Higher K* Resonances (open access)

B0 Meson Decays to Rho0 K*0, F0 K*0, And Rho- K* , Including Higher K* Resonances

None
Date: May 31, 2013
Creator: Lee-Boehm, Corry Louise & U., /Harvard
System: The UNT Digital Library
D = 5 Maximally Supersymmetric Yang-Mills Theory Diverges at Six Loops (open access)

D = 5 Maximally Supersymmetric Yang-Mills Theory Diverges at Six Loops

None
Date: October 31, 2012
Creator: Bern, Zvi; Carrasco, John Joseph; Dixon, Lance J.; Douglas, Michael R.; von Hippel, Matt & Johansson, Henrik
System: The UNT Digital Library
The QCD Phase Diagram: Large Nc, Quarkyonic Matter and the Triple Point (open access)

The QCD Phase Diagram: Large Nc, Quarkyonic Matter and the Triple Point

I discuss the phase diagram of QCD in the large N_c limit. Quarkyonic Matter is described. The properties of QCD matter as measured in the abundance of produced particles are shown to be consistent with this phase diagram. A possible triple point of Hadronic Mater, Deconfined Matter and Quarkyonic matter is shown to explain various behaviors of ratios of particles abundances seen in CERN fixed target experiments.
Date: January 31, 2010
Creator: McLerran, L.
System: The UNT Digital Library
Towards an Integrated Model of the NIC Layered Implosions (open access)

Towards an Integrated Model of the NIC Layered Implosions

A detailed simulation-based model of the June 2011 National Ignition Campaign (NIC) cryogenic DT experiments is presented. The model is based on integrated hohlraum-capsule simulations that utilize the best available models for the hohlraum wall, ablator, and DT equations of state and opacities. The calculated radiation drive was adjusted by changing the input laser power to match the experimentally measured shock speeds, shock merger times, peak implosion velocity, and bangtime. The crossbeam energy transfer model was tuned to match the measured time-dependent symmetry. Mid-mode mix was included by directly modeling the ablator and ice surface perturbations up to mode 60. Simulated experimental values were extracted from the simulation and compared against the experiment. The model adjustments brought much of the simulated data into closer agreement with the experiment, with the notable exception of the measured yields, which were 15-45% of the calculated yields.
Date: October 31, 2011
Creator: Jones, O. S.; Callahan, D. A.; Cerjan, C. J.; Clark, D. S.; Edwards, M. J.; Glenzer, S. H. et al.
System: The UNT Digital Library
es11_Rappe_final_report_DOE.pdf (open access)

es11_Rappe_final_report_DOE.pdf

ES11: the 23rd Annual Workshop on Electronic Structure Methods was held from June 6-9, 2011 at the University of Pennsylvania. The local organizing committee (see Section II) led by PI Andrew M. Rappe supervised the organization of the conference, before, during, and after the meeting itself. The national organizing committee set the technical program of talks, and provided support and advice in various ways. The conference was well-attended (see Section III). An important feature of this conference was a series of panel discussions (see Section IV) to discuss the field of electronic structure and to set new directions. The technical program was of extraordinarily high quality (see Section V). The host institution, the University of Pennsylvania, provided a supportive environment for this meeting (see Section VI).
Date: August 31, 2011
Creator: Rappe, Andrew M.
System: The UNT Digital Library
Shock compression of precompressed deuterium (open access)

Shock compression of precompressed deuterium

Here we report quasi-isentropic dynamic compression and thermodynamic characterization of solid, precompressed deuterium over an ultrafast time scale (< 100 ps) and a microscopic length scale (< 1 {micro}m). We further report a fast transition in shock wave compressed solid deuterium that is consistent with the ramp to shock transition, with a time scale of less than 10 ps. These results suggest that high-density dynamic compression of hydrogen may be possible on microscopic length scales.
Date: July 31, 2011
Creator: Armstrong, M R; Crowhurst, J C; Zaug, J M; Bastea, S; Goncharov, A F & Militzer, B
System: The UNT Digital Library
Overview of Phase Space Manipulations of Relativistic Electron Beams (open access)

Overview of Phase Space Manipulations of Relativistic Electron Beams

Phase space manipulation is a process to rearrange beam's distribution in 6-D phase space. In this paper, we give an overview of the techniques for tailoring beam distribution in 2D, 4D, and 6D phase space to meet the requirements of various applications. These techniques become a new focus of accelerator physics R&D and very likely these advanced concepts will open up new opportunities in advanced accelerators and the science enabled by them.
Date: August 31, 2012
Creator: Xiang, Dao
System: The UNT Digital Library
Generalized Energy-Dependent Q Values for Fission (open access)

Generalized Energy-Dependent Q Values for Fission

We extend Madland's parameterization of the energy release in fission to obtain the dependence of the fission Q value for major and minor actinides on the incident neutron energies in the range 0 {le} E{sub n} {le} 20 MeV. Our parameterization is based on the actinide evaluations recommended for the ENDF/B-VII.1 release. This paper describes the calculation of energydependent fission Q values based on the calculation of the prompt energy release in fission by Madland. This calculation was adopted for use in the LLNL ENDL database and then generalized to obtain the prompt fission energy release for all actinides. Here the calculation is further generalized to the total energy release in fission. There are several stages in a fission event, depending on the time scale. Neutrons and gammas may be emitted at any time during the fission event.While our discussion here is focussed on compound nucleus creation by an incident neutron, similar parameterizations could be obtained for incident gammas or spontaneous fission.
Date: March 31, 2010
Creator: Vogt, R
System: The UNT Digital Library
Comparison of Carbon and Hi-Z Primary Collimators for the LHC Phase II Collimation System (open access)

Comparison of Carbon and Hi-Z Primary Collimators for the LHC Phase II Collimation System

A current issue with the LHC collimation system is single-diffractive, off-energy protons from the primary collimators that pass completely through the secondary collimation system and are absorbed immediately downbeam in the cold magnets of the dispersion suppressor section. Simulations suggest that the high impact rate could result in quenching of these magnets. We have studied replacing the 60 cm primary graphite collimators, which remove halo mainly by inelastic strong interactions, with 5.25 mm tungsten, which remove halo mainly by multiple coulomb scattering and thereby reduce the rate of single-diffractive interactions that cause losses in the dispersion suppressor.
Date: October 31, 2011
Creator: Keller, Lewis; /SLAC; Markiewicz, Thomas; /SLAC; Smith, Jeffrey; /SLAC et al.
System: The UNT Digital Library
AGING PERFORMANCE OF MODEL 9975 PACKAGE FLUOROELASTOMER O-RINGS (open access)

AGING PERFORMANCE OF MODEL 9975 PACKAGE FLUOROELASTOMER O-RINGS

The influence of temperature and radiation on Viton{reg_sign} GLT and GLT-S fluoroelastomer O-rings is an ongoing research focus at the Savannah River National Laboratory. The O-rings are credited for leaktight containment in the Model 9975 shipping package used for transportation of plutonium-bearing materials. At the Savannah River Site, the Model 9975 packages are being used for interim storage. Primary research efforts have focused on surveillance of O-rings from actual packages, leak testing of seals at bounding aging conditions and the effect of aging temperature on compression stress relaxation behavior, with the goal of service life prediction for long-term storage conditions. Recently, an additional effort to evaluate the effect of aging temperature on the oxidation of the materials has begun. Degradation in the mechanical properties of elastomers is directly related to the oxidation of the polymer. Sensitive measurements of the oxidation rate can be performed in a more timely manner than waiting for a measurable change in mechanical properties, especially at service temperatures. Measuring the oxidation rate therefore provides a means to validate the assumption that the degradation mechanisms(s) do not change from the elevated temperatures used for accelerated aging and the lower service temperatures. Monitoring the amount of oxygen uptake …
Date: May 31, 2011
Creator: Hoffman, E.; Daugherty, W.; Skidmore, E.; Dunn, K. & Fisher, D.
System: The UNT Digital Library
FeMn/Fe/Co/Cu(1,1,10) films studied using the magneto-optic Kerr effect and photoemission electron microscopy (open access)

FeMn/Fe/Co/Cu(1,1,10) films studied using the magneto-optic Kerr effect and photoemission electron microscopy

FeMn/Fe/Co/Cu(1,1,10) films were grown epitaxially and investigated using the magneto-optic Kerr effect and photoemission electron microscopy. We found that FeMn/Fe/Co/Cu(1,1,10) exhibits the same properties as FeMn/Co/Cu(1,1,10) for the ferromagnetic phase of the face centered cubic (fcc) Fe film but a different property for the non-ferromagnetic phase of the fcc Fe film. This result indicates that the characteristic property reported in the literature for FeMn/Co/Cu(001) comes from the FeMn spin structure and is independent of the ferromagnetic layer.
Date: July 31, 2011
Creator: Meng, Y.; Li, J.; Tan, A.; Park, J.; Jin, E.; Son, H. et al.
System: The UNT Digital Library
Ion acceleration and cooling in gasless self-sputtering (open access)

Ion acceleration and cooling in gasless self-sputtering

Copper plasma with hyperthermal directed velocity (8.8 eV) but very low temperature (0.6 eV) has been obtained using self-sputtering far above the runaway threshold. Ion energy distribution functions (IEDFs) were simultaneously measured at 34 locations. The IEDFs show the tail of the Thompson distribution near the magnetron target. They transform to shifted Maxwellians with the ions being accelerated and cooled. We deduce the existence of a highly asymmetric, pressure-driven potential hump which acts as a controlling"watershed" between the ion return flux and the expanding plasma.
Date: October 31, 2010
Creator: Horwat, David & Anders, Andre
System: The UNT Digital Library
AlGaN UV LED and Photodiodes Radiation Hardness and Space Qualifications and Their Applications in Space Science and High Energy Density Physics (open access)

AlGaN UV LED and Photodiodes Radiation Hardness and Space Qualifications and Their Applications in Space Science and High Energy Density Physics

This presentation provides an overview of robust, radiation hard AlGaN optoelectronic devices and their applications in space exploration & high energy density physics. Particularly, deep UV LED and deep UV photodiodes are discussed with regard to their applications, radiation hardness and space qualification. AC charge management of UV LED satellite payload instruments, which were to be launched in late 2012, is covered.
Date: May 31, 2011
Creator: Sun, K. X.
System: The UNT Digital Library
Incorporating Experience Curves in Appliance Standards Analysis (open access)

Incorporating Experience Curves in Appliance Standards Analysis

The technical analyses in support of U.S. energy conservation standards for residential appliances and commercial equipment have typically assumed that manufacturing costs and retail prices remain constant during the projected 30-year analysis period. There is, however, considerable evidence that this assumption does not reflect real market prices. Costs and prices generally fall in relation to cumulative production, a phenomenon known as experience and modeled by a fairly robust empirical experience curve. Using price data from the Bureau of Labor Statistics, and shipment data obtained as part of the standards analysis process, we present U.S. experience curves for room air conditioners, clothes dryers, central air conditioners, furnaces, and refrigerators and freezers. These allow us to develop more representative appliance price projections than the assumption-based approach of constant prices. These experience curves were incorporated into recent energy conservation standards for these products. The impact on the national modeling can be significant, often increasing the net present value of potential standard levels in the analysis. In some cases a previously cost-negative potential standard level demonstrates a benefit when incorporating experience. These results imply that past energy conservation standards analyses may have undervalued the economic benefits of potential standard levels.
Date: October 31, 2011
Creator: Garbesi, Karina; Chan, Peter; Greenblatt, Jeffery; Kantner, Colleen; Lekov, Alex; Meyers, Stephen et al.
System: The UNT Digital Library
Transmission Nuclear Resonance Fluorescence Measurements of 238U in Thick Targets (open access)

Transmission Nuclear Resonance Fluorescence Measurements of 238U in Thick Targets

Transmission nuclear resonance fluorescence measurements were made on targets consisting of Pb and depleted U with total areal densities near 86 g/cm2. The 238U content n the targets varied from 0 to 8.5percent (atom fraction). The experiment demonstrates the capability of using transmission measurements as a non-destructive technique to identify and quantify the presence of an isotope in samples with thicknesses comparable to he average thickness of a nuclear fuel assembly. The experimental data also appear to demonstrate the process of notch refilling with a predictable intensity. Comparison of measured spectra to previous backscatter 238U measurements indicates general agreement in observed excited states. Two new 238U excited states and possibly a third state have also been observed.
Date: August 31, 2010
Creator: Quiter, Brian J.; Ludewigt, Bernhard A.; Mozin, Vladimir V.; Wilson, Cody & Korbly, Steve
System: The UNT Digital Library
Ab Initio Many-Body Calculations Of Light-Ion Reactions (open access)

Ab Initio Many-Body Calculations Of Light-Ion Reactions

None
Date: July 31, 2013
Creator: Romero-Redondo, C; Navratil, P; Quaglioni, S; Hupin, G; Langhammer, J; Calci, A et al.
System: The UNT Digital Library
Model-Based Subspace Detectors Constructed with SPECFEM3D (open access)

Model-Based Subspace Detectors Constructed with SPECFEM3D

None
Date: May 31, 2013
Creator: Harris, D. B. & Rodgers, A. J.
System: The UNT Digital Library
Using synthetic biology to screen for functional diversity of GH1 enzymes (open access)

Using synthetic biology to screen for functional diversity of GH1 enzymes

Advances in next-generation sequencing technologies have enabled single genomes as well as complex environmental samples (metagenomes) to be comprehensively sequenced on a routine basis. Bioinformatics analysis of the resulting sequencing data reveals a continually expanding catalogue of predicted proteins ( 14 million as of April 2011), 75 percent of which are associated with functional annotation (COG, Pfam, Enzyme, Kegg, etc). These predicted proteins cover the full spectrum of known pathways and functional activities, including many novel biocatalysts that are expected to significantly contribute to the development of clean technologies including biomass degradation, lipid transformation for biodiesel generation, intermediates for polymer production, carbon capture, and bioremediation.
Date: May 31, 2011
Creator: Deutsch, Sam; Datta, Supratim; Hamilton, Matthew; Friedland, Greg; D'Haeseleer, Patrik; Chen, Jan-Fang et al.
System: The UNT Digital Library
Neutron Production Using a Pyroelectric Driven Target Coupled with a Gated Field Ionization Source (open access)

Neutron Production Using a Pyroelectric Driven Target Coupled with a Gated Field Ionization Source

None
Date: July 31, 2012
Creator: Ellsworth, J L; Tang, V; Falabella, S; Naranjo, B & Putterman, S
System: The UNT Digital Library
Image processing and control of a programmable spatial light modulator (open access)

Image processing and control of a programmable spatial light modulator

None
Date: January 31, 2011
Creator: Awwal, A.; Leach, R.; Brunton, G.; Tse, E.; Matone, J. & Heebner, J.
System: The UNT Digital Library
Transport and Installation of the Dark Energy Survey CCD Imager (open access)

Transport and Installation of the Dark Energy Survey CCD Imager

None
Date: July 31, 2012
Creator: Derylo, Greg; Chi, Edward; Diehl, H.Thomas; Estrada, Juan; Flaugher, Brenna & Schultz, Ken
System: The UNT Digital Library
Advanced Electric Submersible Pump Design Tool for Geothermal Applications (open access)

Advanced Electric Submersible Pump Design Tool for Geothermal Applications

Electrical Submersible Pumps (ESPs) present higher efficiency, larger production rate, and can be operated in deeper wells than the other geothermal artificial lifting systems. Enhanced Geothermal Systems (EGS) applications recommend lifting 300 C geothermal water at 80kg/s flow rate in a maximum 10-5/8-inch diameter wellbore to improve the cost-effectiveness. In this paper, an advanced ESP design tool comprising a 1D theoretical model and a 3D CFD analysis has been developed to design ESPs for geothermal applications. Design of Experiments was also performed to optimize the geometry and performance. The designed mixed-flow type centrifugal impeller and diffuser exhibit high efficiency and head rise under simulated EGS conditions. The design tool has been validated by comparing the prediction to experimental data of an existing ESP product.
Date: May 31, 2012
Creator: Qi, Xuele; Turnquist, Norman & Ghasripoor, Farshad
System: The UNT Digital Library