Constraints on the Phase Plane of the Dark Energy Equation of State (open access)

Constraints on the Phase Plane of the Dark Energy Equation of State

None
Date: July 10, 2013
Creator: Chen, Chien-Wen; /Taiwan, Natl. Normal U.; Chen, Pisin; /Taiwan, Natl. Normal U. /KIPAC, Menlo Park; Gu, Je-An & /Taiwan, Natl. Normal U.
Object Type: Article
System: The UNT Digital Library
Comparison of Waste Feed Delivery Small Scale Mixing Demonstration Simulant to Hanford Waste (open access)

Comparison of Waste Feed Delivery Small Scale Mixing Demonstration Simulant to Hanford Waste

The Hanford double-shell tank (DST) system provides the staging location for waste that will be transferred to the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Specific WTP acceptance criteria for waste feed delivery describe the physical and chemical characteristics of the waste that must be met before the waste is transferred from the DSTs to the WTP. One of the more challenging requirements relates to the sampling and characterization of the undissolved solids (UDS) in a waste feed DST because the waste contains solid particles that settle and their concentration and relative proportion can change during the transfer of the waste in individual batches. A key uncertainty in the waste feed delivery system is the potential variation in UDS transferred in individual batches in comparison to an initial sample used for evaluating the acceptance criteria. To address this uncertainty, a number of small-scale mixing tests have been conducted as part of Washington River Protection Solutions' Small Scale Mixing Demonstration (SSMD) project to determine the performance of the DST mixing and sampling systems. A series of these tests have used a five-part simulant composed of particles of different size and density and designed to be equal or more challenging than …
Date: July 10, 2012
Creator: Wells, Beric E.; Gauglitz, Phillip A. & Rector, David R.
Object Type: Report
System: The UNT Digital Library
A New Electrostatically-focused UV HPD for Liquid Xenon (open access)

A New Electrostatically-focused UV HPD for Liquid Xenon

Appropriate photodetectors are a major challenge for liquid xenon technology as proposed by the next generation of double beta decay, solar neutrino, and dark matter searches. The primary photon signal is tiny and in the hard ultraviolet, the installation is cryogenic, and the sensors themselves must not introduce background. Hybrid photodiodes (HPDs) provide an easy substitute for a conventional PMT with the added advantages of low radioactivity, better area coverage, and single photoelectron counting. A computer-controlled test setup capable of characterizing optical properties of ultraviolet photodetectors was installed. It was used to compare photomultiplier tubes, silicon photomultipliers, avalanche photodiodes, and a novel-design custom HPD developed by the DEP company under this proposal.
Date: July 10, 2013
Creator: Cushman, Priscilla Brooks
Object Type: Report
System: The UNT Digital Library
ACTUAL-WASTE TESTING OF ULTRAVIOLET LIGHT TO AUGMENT THE ENHANCED CHEMICAL CLEANING OF SRS SLUDGE (open access)

ACTUAL-WASTE TESTING OF ULTRAVIOLET LIGHT TO AUGMENT THE ENHANCED CHEMICAL CLEANING OF SRS SLUDGE

In support of Savannah River Site (SRS) tank closure efforts, the Savannah River National Laboratory (SRNL) conducted Real Waste Testing (RWT) to evaluate Enhanced Chemical Cleaning (ECC), an alternative to the baseline 8 wt% oxalic acid (OA) chemical cleaning technology for tank sludge heel removal. ECC utilizes a more dilute OA solution (2 wt%) and an oxalate destruction technology using ozonolysis with or without the application of ultraviolet (UV) light. SRNL conducted tests of the ECC process using actual SRS waste material from Tanks 5F and 12H. The previous phase of testing involved testing of all phases of the ECC process (sludge dissolution, OA decomposition, product evaporation, and deposition tank storage) but did not involve the use of UV light in OA decomposition. The new phase of testing documented in this report focused on the use of UV light to assist OA decomposition, but involved only the OA decomposition and deposition tank portions of the process. Compared with the previous testing at analogous conditions without UV light, OA decomposition with the use of UV light generally reduced time required to reach the target of <100 mg/L oxalate. This effect was the most pronounced during the initial part of the decomposition …
Date: July 10, 2012
Creator: Martino, C.; King, W. & Ketusky, E.
Object Type: Report
System: The UNT Digital Library
Search for Solar Axion Emission from 7Li and D(p,gamma)3He Nuclear Decays with the CAST gamma-ray Calorimeter (open access)

Search for Solar Axion Emission from 7Li and D(p,gamma)3He Nuclear Decays with the CAST gamma-ray Calorimeter

None
Date: July 10, 2013
Creator: Andriamonje, S.; Aune, S.; Autiero, D.; Barth, K.; Belov, A.; Beltran, B. et al.
Object Type: Article
System: The UNT Digital Library
Ice Formation in Gas-Diffusion Layers (open access)

Ice Formation in Gas-Diffusion Layers

Under sub-freezing conditions, ice forms in the gas-diffusion layer (GDL) of a proton exchange membrane fuel cell (PEMFC) drastically reducing cell performance. Although a number of strategies exist to prevent ice formation, there is little fundamental understanding of the mechanisms of freezing within PEMFC components. Differential scanning calorimetry (DSC) is used to elucidate the effects of hydrophobicity (Teflon® loading) and water saturation on the rate of ice formation within three commercial GDLs. We find that as the Teflon® loading increases, the crystallization temperature decreases due to a change in internal ice/substrate contact angle, as well as the attainable level of water saturation. Classical nucleation theory predicts the correct trend in freezing temperature with Teflon® loading.
Date: July 10, 2010
Creator: Dursch, Thomas; Radke, Clayton J. & Weber, Adam Z.
Object Type: Article
System: The UNT Digital Library
QCD Radiation in the Production of Heavy Colored Particles at the LHC (open access)

QCD Radiation in the Production of Heavy Colored Particles at the LHC

None
Date: July 10, 2013
Creator: Alwall, Johan; de Visscher, Simon & Maltoni, Fabio
Object Type: Article
System: The UNT Digital Library
DEVELOPMENT OF THE HS99 AIR TRANSPORT TYPE A FISSILE PACKAGE (open access)

DEVELOPMENT OF THE HS99 AIR TRANSPORT TYPE A FISSILE PACKAGE

An air-transport Type A Fissile radioactive shipping package for the transport of special form uranium sources has been developed by the Savannah River National Laboratory (SRNL) for the Department of Homeland Security. The Package model number is HS99 for Homeland Security Model 99. This paper presents the major design features of the HS99 and highlights engineered materials necessary for meeting the design requirements for this light-weight Type AF packaging. A discussion is provided demonstrating how the HS99 complies with the regulatory safety requirements of the Nuclear Regulatory Commission. The paper summarizes the results of structural testing to specified in 10 CFR 71 for Normal Conditions of Transport and Hypothetical Accident Conditions events. Planned and proposed future missions for this packaging are also addressed.
Date: July 10, 2012
Creator: Blanton, P. & Eberl, K.
Object Type: Article
System: The UNT Digital Library
Reduction in Fabrication Costs of Gas Diffusion Layers (open access)

Reduction in Fabrication Costs of Gas Diffusion Layers

Ballard Material Products (BMP) performed a pre-design technical and cost analysis of state of the art production technologies feasible for high volume GDL manufacturing. Based upon criteria that also included environmental health and safety, customer quality requirements, and future needs, BMP selected technologies that can be integrated into its current manufacturing process. These selections included Many-At-A-Time (MAAT) coating and continuous mixing technologies, as well as various on-line process control tools. These processes have allowed BMP to produce high performance GDLs at lower cost for near-term markets, as well as to define the inputs needed to develop a conceptual Greenfield facility to meet the cost targets for automotive volumes of 500,000 vehicles per year.
Date: July 10, 2012
Creator: Morgan, Jason; Connors, Donald & Hickner, Michael
Object Type: Report
System: The UNT Digital Library
Consistency Test of Dark Energy Models (open access)

Consistency Test of Dark Energy Models

None
Date: July 10, 2013
Creator: Chen, Chien-Wen.; /Taiwan, Natl. Taiwan U.; Gu, Je-An.; /Taiwan, Natl. Taiwan U.; Chen, Pisin. & /KIPAC, Menlo Park /Taiwan, Natl. Taiwan U. /Taipei, Inst. Astron. Astrophys.
Object Type: Article
System: The UNT Digital Library
17 GHz High Gradient Accelerator Research (open access)

17 GHz High Gradient Accelerator Research

This is a report on the MIT High Gradient Accelerator Research program which has included: Operation of the 17 GHz, 25 MeV MIT/Haimson Research Corp. electron accelerator at MIT, the highest frequency, stand-alone accelerator in the world; collaboration with members of the US High Gradient Collaboration, including the design and test of novel structures at SLAC at 11.4 GHz; the design, construction and testing of photonic bandgap structures, including metallic and dielectric structures; the investigation of the wakefields in novel structures; and the training of the next generation of graduate students and postdoctoral associates in accelerator physics.
Date: July 10, 2013
Creator: Temkin, Richard J. & Shapiro, Michael A.
Object Type: Report
System: The UNT Digital Library
NUMERICAL RECIPES FOR EQUIVALENT CONTINUUM MODELING OF JOINTED SYSTEMS (open access)

NUMERICAL RECIPES FOR EQUIVALENT CONTINUUM MODELING OF JOINTED SYSTEMS

None
Date: July 10, 2012
Creator: Vorobiev, O & Herbold, E
Object Type: Article
System: The UNT Digital Library
ArborZ: Photometric Redshifts Using Boosted Decision Trees (open access)

ArborZ: Photometric Redshifts Using Boosted Decision Trees

None
Date: July 10, 2013
Creator: Gerdes, David W.; Sypniewski, Adam J.; McKay, Timothy A.; Hao, Jiangang; Weis, Matthew R.; U., /Michigan et al.
Object Type: Article
System: The UNT Digital Library
Fermionic Corrections to the Heavy-Quark Pair Production in the Quark-Antiquark Channel (open access)

Fermionic Corrections to the Heavy-Quark Pair Production in the Quark-Antiquark Channel

None
Date: July 10, 2013
Creator: Bonciani, R.; Ferroglia, A.; Gehrmann, T.; Studerus, C.; U., /Zurich & Maitre, D.
Object Type: Article
System: The UNT Digital Library
Bianchi Attractors: A Classification of Extremal Black Brane Geometries (open access)

Bianchi Attractors: A Classification of Extremal Black Brane Geometries

None
Date: July 10, 2013
Creator: Iizuka, Norihiro; /CERN; Kachru, Shamit; /Stanford U., ITP /SLAC; Kundu, Nilay; Narayan, Prithvi et al.
Object Type: Article
System: The UNT Digital Library
25 Year Lifetime for Flexible Buildings Integrated Photovoltaics (open access)

25 Year Lifetime for Flexible Buildings Integrated Photovoltaics

Although preliminary proof-of-principle of the efficacy of barrier materials and processes, first developed by Battelle at PNNL and commercialized by Vitex, has been demonstrated at the laboratory scale, there are several challenges to the practical commercial implementation of these developments in the Buildings Integrated Photovoltaics (BIPV) market. Two important issues that are addressed in this project are identifying a low cost substrate material that can survive in the outside environment (rain, heat, dust, hail, etc.) for 25 years and developing an encapsulation method for the photovoltaic (PV) cells that can meet the required barrier performance without driving the cost of the total barrier package out of range (remaining below $3.00/Wp). Without these solutions, current encapsulation technologies will limit the use of PV for BIPV applications. Flexible, light-weight packaging that can withstand 25 years in the field is required for a totally flexible integrated PV package. The benefit of this research is to make substantial progress in the development of a cost-effective, viable thin film barrier package which will be a critical enabling technology to meet the Solar America Initiative cost and device reliability goals, and to make photovoltaics (PV) more cost-competitive with electricity generated using fossil fuels. Increased PV installations …
Date: July 10, 2010
Creator: Gross, Mark E.
Object Type: Report
System: The UNT Digital Library
Mach-Zehnder Modulator Performance Using the Comet Laser Facility and Implications for Use on NIF (open access)

Mach-Zehnder Modulator Performance Using the Comet Laser Facility and Implications for Use on NIF

None
Date: July 10, 2012
Creator: Beeman, B.; MacPhee, A. G.; Kimbrough, J. R.; Lacaille, G. A.; Barrios, M. A.; Emig, J. et al.
Object Type: Article
System: The UNT Digital Library
High Temperature coatings based on {beta}-NiAI (open access)

High Temperature coatings based on {beta}-NiAI

High temperature alloys are reviewed, focusing on current superalloys and their coatings. The synthesis, characerization, and oxidation performance of a NiAl–TiB{sub 2} composite are explained. A novel coating process for Mo–Ni–Al alloys for improved oxidation performance is examined. The cyclic oxidation performance of coated and uncoated Mo–Ni–Al alloys is discussed.
Date: July 10, 2012
Creator: Severs, Kevin
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Computational Eulerian Hydrodynamics and Galilean Invariance (open access)

Computational Eulerian Hydrodynamics and Galilean Invariance

Eulerian hydrodynamical simulations are a powerful and popular tool for modeling fluids in astrophysical systems. In this work, we critically examine recent claims that these methods violate Galilean invariance of the Euler equations. We demonstrate that Eulerian hydrohynamics methods do converge to a Galilean-invariant solution,provided a well-defined convergent solutions exists. Specifically, we show that numerical diffusion, resulting from diffusion-like terms in the discretized hydrodynamical equations solved by Eulerian methods, accounts for the effects previously identified as evidence for the Galilean non-inveriance of these methods. These velocity-dependent diffusive terms lead to different results for different bulk velocities when the spatial resolution of the simulation is kept fixed, but their effect become negligible as the resolution of the simulation is increased to obtain a converged solution. In particular, we find that Kelvin-Helmholtz instabilities develop properly in realistic Eulerian calculations regardless of the bulk velocity provided the problem is simulated with sufficient resolution (a factor of 2-4 increase compared to the case without bulk flows for realistic velocities). Our results reiterate that high-resolution Eulerian methods can perform well and obtain a convergent solution, even in the presence of highly supersonic bulk flows.
Date: July 10, 2013
Creator: Robertson, Brant E.; Kravtsov, Andrey V.; /Chicago U., KICP /Chicago U., Astron. Astrophys. Ctr.; Gnedin, Nickolay Y.; /Chicago U., KICP /Fermilab; Abel, Tom et al.
Object Type: Article
System: The UNT Digital Library
X-ray Nanoscope for Electronics Assurance (open access)

X-ray Nanoscope for Electronics Assurance

None
Date: July 10, 2013
Creator: Martz, H E; Kallman, J S; Divin, C J & Azevedo, S
Object Type: Report
System: The UNT Digital Library
A 4.2 GS/sec. Synchronized Vertical Excitation System for SPS Studies - Steps Toward Wideband Feedback (open access)

A 4.2 GS/sec. Synchronized Vertical Excitation System for SPS Studies - Steps Toward Wideband Feedback

A 4.2 GS/sec. beam excitation system with accelerator synchronization and power stages is described. The system is capable of playing unique samples (32 samples/bunch) for 15,000 turns on selected bunch(es) in the SPS in syn- chronism with the injection and acceleration cycle. The purpose of the system is to excite internal modes of single-bunch vertical motion, and study the bunch dynamics in the presence of developing Electron cloud or TMCI effects. The system includes a synchronized master oscillator, SPS timing functions, an FPGA based arbitrary waveform generator, 4.2 GS/sec. D/A system and four 80W 20-1000 MHz amplifiers driving a tapered stripline pickup/kicker. A software GUI allows specification of various modulation signals, selection of bunches and turns to excite, while a remote control interface allows simple control/monitoring of the RF power stages located in the tunnel. The successful use of this system for SPS MD measurements in 2011 is a vital proof-of-principle for wideband feedback using similar functions to correct the beam motion.
Date: July 10, 2012
Creator: Fox, John
Object Type: Article
System: The UNT Digital Library
Advances in NIF Shock Timing Experiments (open access)

Advances in NIF Shock Timing Experiments

None
Date: July 10, 2012
Creator: Robey, H. F.; Celliers, P. M.; Moody, J. D. & MacKinnon, A. J.
Object Type: Article
System: The UNT Digital Library
Optimisation of NSLS-II Blade X-ray Beam Position Monitors: from Photoemission type to Diamond Detector (open access)

Optimisation of NSLS-II Blade X-ray Beam Position Monitors: from Photoemission type to Diamond Detector

Optimisation of blade type x-ray beam position monitors (XBPM) was performed for NSLS-II undulator IVU20. Blade material, con and #64257;guration and operation principle was analysed in order to improve XBPM performance. Optimisation is based on calculation of the XBPM signal spatial distribution. Along with standard photoemission type XBPM a Diamond Detector Blades (DDB) were analysed as blades for XBPMs. DDB XBPMs can help to overcome drawbacks of the photoemission blade XBPMs.
Date: July 10, 2012
Creator: P., ILINSKI
Object Type: Report
System: The UNT Digital Library
Development Of Chemical Reduction And Air Stripping Processes To Remove Mercury From Wastewater (open access)

Development Of Chemical Reduction And Air Stripping Processes To Remove Mercury From Wastewater

This study evaluates the removal of mercury from wastewater using chemical reduction and air stripping using a full-scale treatment system at the Savannah River Site. The existing water treatment system utilizes air stripping as the unit operation to remove organic compounds from groundwater that also contains mercury (C ~ 250 ng/L). The baseline air stripping process was ineffective in removing mercury and the water exceeded a proposed limit of 51 ng/L. To test an enhancement to the existing treatment modality a continuous dose of reducing agent was injected for 6-hours at the inlet of the air stripper. This action resulted in the chemical reduction of mercury to Hg(0), a species that is removable with the existing unit operation. During the injection period a 94% decrease in concentration was observed and the effluent satisfied proposed limits. The process was optimized over a 2-day period by sequentially evaluating dose rates ranging from 0.64X to 297X stoichiometry. A minimum dose of 16X stoichiometry was necessary to initiate the reduction reaction that facilitated the mercury removal. Competing electron acceptors likely inhibited the reaction at the lower 1 doses, which prevented removal by air stripping. These results indicate that chemical reduction coupled with air stripping …
Date: July 10, 2013
Creator: Jackson, Dennis G.; Looney, Brian B.; Craig, Robert R.; Thompson, Martha C. & Kmetz, Thomas F.
Object Type: Article
System: The UNT Digital Library