Event-by-event study of photon observables in spontaneous and thermal fission (open access)

Event-by-event study of photon observables in spontaneous and thermal fission

None
Date: September 26, 2012
Creator: Vogt, R & Randrup, J
System: The UNT Digital Library
Performance Characteristics of Hardware Transactional Memory for Molecular Dynamics Application on BlueGene/Q: Toward Efficient Multithreading Strategies for Large-Scale Scientific Applications (open access)

Performance Characteristics of Hardware Transactional Memory for Molecular Dynamics Application on BlueGene/Q: Toward Efficient Multithreading Strategies for Large-Scale Scientific Applications

None
Date: September 26, 2012
Creator: Kunaseth, M.; Kalia, R. K.; Nakano, A.; Vashishta, P.; Richards, D. F. & Glosli, J. N.
System: The UNT Digital Library
Position Stability Monitoring of THEthe LCLS Undulator Quadrupoles (open access)

Position Stability Monitoring of THEthe LCLS Undulator Quadrupoles

X-ray FELs demand that the positions of undulator components be stable to less than 1 {mu}m per day. Simultaneously, the undulator length increases significantly in order to saturate at x-ray wavelengths. To minimize the impact of the outside environment, the Linac Coherent Light Source (LCLS) undulator is placed underground, but reliable data about ground motion inside such a tunnel was not available in the required stability range during the planning phase. Therefore, a new position monitor system had been developed and installed with the LCLS undulator. This system is capable of measuring x, y, roll, pitch and yaw of each of the 33 undulator quadrupoles with respect to stretched wires. Instrument resolution is about 10 nm and instrument drift is negligible. Position data of individual quadrupoles can be correlated along the entire 132-m long undulator. The system has been under continuous operation since 2009. This report describes long term experiences with the running system and the observed positional stability of the undulator quadrupoles.
Date: March 26, 2012
Creator: Nuhn, Heinz Dieter; Gassner, Georg & Peters, Franz
System: The UNT Digital Library
Metallic Membrane Materials Development for Hydrogen Production from Coal Derived Syngas (open access)

Metallic Membrane Materials Development for Hydrogen Production from Coal Derived Syngas

The goals of Office of Clean Coal are: (1) Improved energy security; (2) Reduced green house gas emissions; (3) High tech job creation; and (4) Reduced energy costs. The goals of the Hydrogen from Coal Program are: (1) Prove the feasibility of a 40% efficient, near zero emissions IGCC plant that uses membrane separation technology and other advanced technologies to reduce the cost of electricity by at least 35%; and (2) Develop H{sub 2} production and processing technologies that will contribute {approx}3% in improved efficiency and 12% reduction in cost of electricity.
Date: February 26, 2012
Creator: Dogan, O. N.; Howard, B. H. & Alman, D. E.
System: The UNT Digital Library
Gamma discrimination in pillar structured thermal neutron detectors (open access)

Gamma discrimination in pillar structured thermal neutron detectors

Solid-state thermal neutron detectors are desired to replace {sup 3}He tube based technology for the detection of special nuclear materials. {sup 3}He tubes have some issues with stability, sensitivity to microphonics and very recently, a shortage of {sup 3}He. There are numerous solid-state approaches being investigated that utilize various architectures and material combinations. By using the combination of high-aspect-ratio silicon PIN pillars, which are 2 {micro}m wide with a 2 {micro}m separation, arranged in a square matrix, and surrounded by {sup 10}B, the neutron converter material, a high efficiency thermal neutron detector is possible. Besides intrinsic neutron detection efficiency, neutron to gamma discrimination is an important figure of merit for unambiguous signal identification. In this work, theoretical calculations and experimental measurements are conducted to determine the effect of structure design of pillar structured thermal neutron detectors including: intrinsic layer thickness, pillar height, substrate doping and incident gamma energy on neutron to gamma discrimination.
Date: March 26, 2012
Creator: Shao, Q.; Radev, R. P.; Conway, A. M.; Voss, L. F.; Wang, T. F.; Nikolic, R. J. et al.
System: The UNT Digital Library
General Relativistic Magnetohydrodynamic Simulations of Magnetically Choked Accretion Flows around Black Holes (open access)

General Relativistic Magnetohydrodynamic Simulations of Magnetically Choked Accretion Flows around Black Holes

Black hole (BH) accretion flows and jets are qualitatively affected by the presence of ordered magnetic fields. We study fully three-dimensional global general relativistic magnetohydrodynamic (MHD) simulations of radially extended and thick (height H to cylindrical radius R ratio of |H/R| {approx} 0.2-1) accretion flows around BHs with various dimensionless spins (a/M, with BH mass M) and with initially toroidally-dominated ({phi}-directed) and poloidally-dominated (R-z directed) magnetic fields. Firstly, for toroidal field models and BHs with high enough |a/M|, coherent large-scale (i.e. >> H) dipolar poloidal magnetic flux patches emerge, thread the BH, and generate transient relativistic jets. Secondly, for poloidal field models, poloidal magnetic flux readily accretes through the disk from large radii and builds-up to a natural saturation point near the BH. While models with |H/R| {approx} 1 and |a/M| {le} 0.5 do not launch jets due to quenching by mass infall, for sufficiently high |a/M| or low |H/R| the polar magnetic field compresses the inflow into a geometrically thin highly non-axisymmetric 'magnetically choked accretion flow' (MCAF) within which the standard linear magneto-rotational instability is suppressed. The condition of a highly-magnetized state over most of the horizon is optimal for the Blandford-Znajek mechanism that generates persistent relativistic jets with …
Date: April 26, 2012
Creator: McKinney, Jonathan C.; Tchekhovskoy, Alexander & Blandford, Roger D.
System: The UNT Digital Library
Measurement of the Cosmic Ray Energy Spectrum Using Hybrid Events of the Pierre Auger Observatory (open access)

Measurement of the Cosmic Ray Energy Spectrum Using Hybrid Events of the Pierre Auger Observatory

None
Date: June 26, 2012
Creator: Settimo, Mariangela & U., /Siegen u. /Salento
System: The UNT Digital Library
HANFORD RIVER PROTECTION PROJECT ENHANCED MISSION PLANNING THROUGH INNOVATIVE TOOLS LIFECYCLE COST MODELING AND AQUEOUS THERMODYNAMIC MODELING - 12134 (open access)

HANFORD RIVER PROTECTION PROJECT ENHANCED MISSION PLANNING THROUGH INNOVATIVE TOOLS LIFECYCLE COST MODELING AND AQUEOUS THERMODYNAMIC MODELING - 12134

Two notable modeling efforts within the Hanford Tank Waste Operations Simulator (HTWOS) are currently underway to (1) increase the robustness of the underlying chemistry approximations through the development and implementation of an aqueous thermodynamic model, and (2) add enhanced planning capabilities to the HTWOS model through development and incorporation of the lifecycle cost model (LCM). Since even seemingly small changes in apparent waste composition or treatment parameters can result in large changes in quantities of high-level waste (HLW) and low-activity waste (LAW) glass, mission duration or lifecycle cost, a solubility model that more accurately depicts the phases and concentrations of constituents in tank waste is required. The LCM enables evaluation of the interactions of proposed changes on lifecycle mission costs, which is critical for decision makers.
Date: January 26, 2012
Creator: KL, PIERSON & FL, MEINERT
System: The UNT Digital Library
Microstructure and Corrosion Behavior of the Cu-Pd-X Ternary Alloys for Hydrogen Separation Membranes (open access)

Microstructure and Corrosion Behavior of the Cu-Pd-X Ternary Alloys for Hydrogen Separation Membranes

CuPd alloys are among the most promising candidate materials for hydrogen separation membranes and membrane reactor applications due to their high hydrogen permeability and better sulfur resistance. In order to reduce the Pd content and, therefore, the cost of the membrane materials, efforts have been initiated to develop CuPdM ternary alloys having a bcc structure. The advantages of having Pd as a hydrogen separation membrane are: (1) high hydrogen selectivity; and (2) high hydrogen permeability. The disadvantages are: (1) high cost; (2) hydrogen embrittlement ({alpha} {yields} {beta} Pd hydride); and (3) sulfur poisoning. Experiments (XRD, SEM/EDS) verified that Mg, Al, La, Y and Ti are promising alloying elements to expand the B2 phase region in Cu-Pd binary system. HT-XRD showed that the B2 to FCC transition temperatures for Cu-Pd-X (X = Mg, Al, La, Y and Ti) are higher than that of Cu-Pd binary alloys. While the Cu-50Pd alloy had the highest corrosion resistance to the H2S containing syngas, the Cu-Pd-Mg alloy had a comparable resistance.
Date: February 26, 2012
Creator: Dogan, O. N.; Gao, M. C. & Howard, B. H.
System: The UNT Digital Library
FULL SCALE TESTING TECHNOLOGY MATURATION OF A THIN FILM EVAPORATOR FOR HIGH-LEVEL LIQUID WASTE MANAGEMENT AT HANFORD - 12125 (open access)

FULL SCALE TESTING TECHNOLOGY MATURATION OF A THIN FILM EVAPORATOR FOR HIGH-LEVEL LIQUID WASTE MANAGEMENT AT HANFORD - 12125

Simulant testing of a full-scale thin-film evaporator system was conducted in 2011 for technology development at the Hanford tank farms. Test results met objectives of water removal rate, effluent quality, and operational evaluation. Dilute tank waste simulant, representing a typical double-shell tank supernatant liquid layer, was concentrated from a 1.1 specific gravity to approximately 1.5 using a 4.6 m{sup 2} (50 ft{sup 2}) heated transfer area Rototherm{reg_sign} evaporator from Artisan Industries. The condensed evaporator vapor stream was collected and sampled validating efficient separation of the water. An overall decontamination factor of 1.2E+06 was achieved demonstrating excellent retention of key radioactive species within the concentrated liquid stream. The evaporator system was supported by a modular steam supply, chiller, and control computer systems which would be typically implemented at the tank farms. Operation of these support systems demonstrated successful integration while identifying areas for efficiency improvement. Overall testing effort increased the maturation of this technology to support final deployment design and continued project implementation.
Date: January 26, 2012
Creator: AR, TEDESCHI; JE, CORBETT; RA, WILSON & J, LARKIN
System: The UNT Digital Library
Forward Drell-Yan plus backward jet as a test of BFKL evolution (open access)

Forward Drell-Yan plus backward jet as a test of BFKL evolution

N/A
Date: March 26, 2012
Creator: M., Hentschinski & Salas, C.
System: The UNT Digital Library
THERMAL UPGRADING OF 9977 RADIOACTIVE MATERIAL (RAM) TYPE B PACKAGE (open access)

THERMAL UPGRADING OF 9977 RADIOACTIVE MATERIAL (RAM) TYPE B PACKAGE

The 9977 package is a radioactive material package that was originally certified to ship Heat Sources and RTG contents up to 19 watts and it is now being reviewed to significantly expand its contents in support of additional DOE missions. Thermal upgrading will be accomplished by employing stacked 3013 containers, a 3013 aluminum spacer and an external aluminum sleeve for enhanced heat transfer. The 7th Addendum to the original 9977 package Safety Basis Report describing these modifications is under review for the DOE certification. The analyses described in this paper show that this well-designed and conservatively analyzed package can be upgraded to carry contents with decay heat up to 38 watts with some simple design modifications. The Model 9977 package has been designed as a replacement for the Department of Transportation (DOT) Fissile Specification 6M package. The 9977 package is a very versatile Type B package which is certified to transport and store a wide spectrum of radioactive materials. The package was analyzed quite conservatively to increase its usefulness and store different payload configurations. Its versatility is evident from several daughter packages such as the 9978 and H1700, and several addendums where the payloads have been modified to suit the …
Date: March 26, 2012
Creator: Gupta, N. & Abramczyk, G.
System: The UNT Digital Library
Ultra-relativistic Heavy-ion Physics with AFTER@LHC (open access)

Ultra-relativistic Heavy-ion Physics with AFTER@LHC

None
Date: November 26, 2012
Creator: Rakotozafindrabe, A.; Arnaldi, R.; Brodsky, S.J.; Chambert, V.; Didelez, J.P.; Genolini, B. et al.
System: The UNT Digital Library
Helicity Parton Distributions at an EIC (open access)

Helicity Parton Distributions at an EIC

N/A
Date: March 26, 2012
Creator: C., Aschenauer E.; Sassot, R. & Stratmann, M.
System: The UNT Digital Library
Workshop on Fukushima Data Compilation (U) (open access)

Workshop on Fukushima Data Compilation (U)

None
Date: March 26, 2012
Creator: Wimer, N G
System: The UNT Digital Library
ESTIMATED SIL LEVELS AND RISK COMPARISONS FOR RELIEF VALVES AS A FUNCTION OF TIME-IN-SERVICE (open access)

ESTIMATED SIL LEVELS AND RISK COMPARISONS FOR RELIEF VALVES AS A FUNCTION OF TIME-IN-SERVICE

Risk-based inspection methods enable estimation of the probability of spring-operated relief valves failing on demand at the United States Department of Energy's Savannah River Site (SRS) in Aiken, South Carolina. The paper illustrates an approach based on application of the Frechet and Weibull distributions to SRS and Center for Chemical Process Safety (CCPS) Process Equipment Reliability Database (PERD) proof test results. The methodology enables the estimation of ANSI/ISA-84.00.01 Safety Integrity Levels (SILs) as well as the potential change in SIL level due to modification of the maintenance schedule. Current SRS practices are reviewed and recommendations are made for extending inspection intervals. The paper compares risk-based inspection with specific SILs as maintenance intervals are adjusted. Groups of valves are identified in which maintenance times can be extended as well as different groups in which an increased safety margin may be needed.
Date: March 26, 2012
Creator: Harris, S.
System: The UNT Digital Library
Beyond Mean-Field Calculation For Pairing Correlation (open access)

Beyond Mean-Field Calculation For Pairing Correlation

None
Date: April 26, 2012
Creator: Hupin, G & Lacroix, D
System: The UNT Digital Library
Alignment of an x-Ray Imager Line of Sight in the National Ignition Facility (NIF) Target Chamber using a Diagnostic Instrument Manipulator (DIM) and Opposed Port Alignment System (OPAS) (open access)

Alignment of an x-Ray Imager Line of Sight in the National Ignition Facility (NIF) Target Chamber using a Diagnostic Instrument Manipulator (DIM) and Opposed Port Alignment System (OPAS)

None
Date: July 26, 2012
Creator: Shingleton, N.; Kalantar, D.; Wood, R.; McCarville, T.; Klingmann, J. & Manuel, S.
System: The UNT Digital Library
Phase Transition in BCx system under High-Pressure and High-Temperature: Synthesis of Cubic Dense BC3 Nanostructured Phase (open access)

Phase Transition in BCx system under High-Pressure and High-Temperature: Synthesis of Cubic Dense BC3 Nanostructured Phase

None
Date: May 26, 2012
Creator: Zinin, P. V.; Ming, L. C.; Ishii, H. A.; Jia, R.; Acosta, T. & Hellebrand, E.
System: The UNT Digital Library
Disruptions, Disruptivity, and Safer Operating Windows in the High-β Spherical Torus NSTX (open access)

Disruptions, Disruptivity, and Safer Operating Windows in the High-β Spherical Torus NSTX

A fusion pilot plant study was initiated to clarify the development needs in moving from ITER to a first of a kind fusion power plant. The mission of the pilot plant was set to encompass component test and fusion nuclear science missions yet produce net electricity with high availability in a device designed to be prototypical of the commercial device. The objective of the study was to evaluate three different magnetic configuration options, the advanced tokamak (AT), spherical tokamak (ST) and compact stellarator (CS) in an effort to establish component characteristics, maintenance features and the general arrangement of each candidate device. With the move to look beyond ITER the fusion community is now beginning to embark on DEMO reactor studies with an emphasis on defining configuration arrangements that can meet a high availability goal. This paper reviews the AT pilot plant design, detailing the selected maintenance approach, the device arrangement and sizing of the in-vessel components. Details of interfacing auxiliary systems and services that impact the ability to achieve high availability operations will also be discussed.
Date: September 26, 2012
Creator: Brown, T.; Goldston, R. J.; El-Guebaly, L.; Kessel, C.; Neilson, G. H.; Malang, S. et al.
System: The UNT Digital Library
A Large Hadron Electron Collider at CERN: Report on the Physics and Design Concepts for Machine and Detector (open access)

A Large Hadron Electron Collider at CERN: Report on the Physics and Design Concepts for Machine and Detector

None
Date: September 26, 2012
Creator: Fernandez, J. L. Abelleira; Adolphsen, C.; Akay, A. N.; Aksakal, H.; Albacete, J. L.; Alekhin, S. et al.
System: The UNT Digital Library
Large N (=3) Neutrinos and Random Matrix Theory (open access)

Large N (=3) Neutrinos and Random Matrix Theory

None
Date: October 26, 2012
Creator: Bai, Yang & Torroba, Gonzalo
System: The UNT Digital Library
COMPARISON OF EXPERIMENTS TO CFD MODELS FOR MIXING USING DUAL OPPOSING JETS IN TANKS WITH AND WITHOUT INTERNAL OBSTRUCTIONS (open access)

COMPARISON OF EXPERIMENTS TO CFD MODELS FOR MIXING USING DUAL OPPOSING JETS IN TANKS WITH AND WITHOUT INTERNAL OBSTRUCTIONS

This paper documents testing methods, statistical data analysis, and a comparison of experimental results to CFD models for blending of fluids, which were blended using a single pump designed with dual opposing nozzles in an eight foot diameter tank. Overall, this research presents new findings in the field of mixing research. Specifically, blending processes were clearly shown to have random, chaotic effects, where possible causal factors such as turbulence, pump fluctuations, and eddies required future evaluation. CFD models were shown to provide reasonable estimates for the average blending times, but large variations -- or scatter -- occurred for blending times during similar tests. Using this experimental blending time data, the chaotic nature of blending was demonstrated and the variability of blending times with respect to average blending times were shown to increase with system complexity. Prior to this research, the variation in blending times caused discrepancies between CFD models and experiments. This research addressed this discrepancy, and determined statistical correction factors that can be applied to CFD models, and thereby quantified techniques to permit the application of CFD models to complex systems, such as blending. These blending time correction factors for CFD models are comparable to safety factors used in …
Date: June 26, 2012
Creator: Leishear, R.; Poirier, M.; Lee, S. & Fowley, M.
System: The UNT Digital Library
ROSE::FTTransform - A Source-to-Source Translation Framework for Exascale Fault-Tolerance Research (open access)

ROSE::FTTransform - A Source-to-Source Translation Framework for Exascale Fault-Tolerance Research

Exascale computing systems will require sufficient resilience to tolerate numerous types of hardware faults while still assuring correct program execution. Such extreme-scale machines are expected to be dominated by processors driven at lower voltages (near the minimum 0.5 volts for current transistors). At these voltage levels, the rate of transient errors increases dramatically due to the sensitivity to transient and geographically localized voltage drops on parts of the processor chip. To achieve power efficiency, these processors are likely to be streamlined and minimal, and thus they cannot be expected to handle transient errors entirely in hardware. Here we present an open, compiler-based framework to automate the armoring of High Performance Computing (HPC) software to protect it from these types of transient processor errors. We develop an open infrastructure to support research work in this area, and we define tools that, in the future, may provide more complete automated and/or semi-automated solutions to support software resiliency on future exascale architectures. Results demonstrate that our approach is feasible, pragmatic in how it can be separated from the software development process, and reasonably efficient (0% to 30% overhead for the Jacobi iteration on common hardware; and 20%, 40%, 26%, and 2% overhead for …
Date: March 26, 2012
Creator: Lidman, J; Quinlan, D; Liao, C & McKee, S
System: The UNT Digital Library