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Lepton Universality, |V(Us)| and Search for Second Class Current in Tau Decays (open access)

Lepton Universality, |V(Us)| and Search for Second Class Current in Tau Decays

Several hundred million {tau} decays have been studied with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory. Recent results on Charged Current Lepton Universality and two independent measurements of |V{sub us}| using {tau}{sup -} {yields} e{sup -}{bar {nu}}{sub e}{nu}{sub {tau}}, {mu}{sup -}{bar {nu}}{sub {mu}}{nu}{sub {tau}}, {pi}{sup -}{nu}{sub {tau}}, K{sup -} {nu}{sub {tau}} and K{sub S}{sup 0}{pi}{sup -} {nu}{sub {tau}} decays, and a search for Second Class Current in {tau}{sup -} {yields} {pi}{sup -} {omega}{nu}{sub {tau}} decays are presented, where the charge conjugate decay modes are also implied.
Date: November 10, 2011
Creator: Banerjee, Swagato
Object Type: Article
System: The UNT Digital Library
Surface Tension Estimates for Droplet Formation in Slurries with Low Concentrations of Hydrophobic Particles, Polymer Flocculants or Surface-Active Contaminants (open access)

Surface Tension Estimates for Droplet Formation in Slurries with Low Concentrations of Hydrophobic Particles, Polymer Flocculants or Surface-Active Contaminants

In support of the K-Basin project, Pacific Northwest National Laboratory (PNNL) was requested to evaluate the appropriate surface tension value to use in models predicting the formation of droplets from spray leaks of K-Basin slurries. The specific issue was whether it was more appropriate to use the surface tension of pure water in model predictions for all plausible spray leaks or to use a lower value. The surface tension of K-Basin slurries is potentially affected not only by particles but by low concentrations of nonionic polyacrylamide flocculant and perhaps by contaminants with surfactant properties, which could decrease the surface tension below that of water. A lower surface tension value typically results in smaller droplets being formed with a larger fraction of droplets in the respirable size range, so using the higher surface tension value of pure water is not conservative and thus needs a strong technical basis.
Date: June 10, 2011
Creator: Gauglitz, Phillip A.; Mahoney, Lenna A.; Blanchard, Jeremy & Bamberger, Judith A.
Object Type: Report
System: The UNT Digital Library
A COMPREHENSIVE ANALYSIS OF CHLORINE TRANSPORT AND FATE FOLLOWING A LARGE ENVIRONMENTAL RELEASE (open access)

A COMPREHENSIVE ANALYSIS OF CHLORINE TRANSPORT AND FATE FOLLOWING A LARGE ENVIRONMENTAL RELEASE

A train derailment occurred in Graniteville, South Carolina during the early morning of January 6, 2005, and resulted in the release of a large amount of cryogenic pressurized liquid chlorine to the environment in a short time period. A comprehensive evaluation of the transport and fate of the released chlorine was performed, accounting for dilution, diffusion, transport and deposition into the local environment. This involved the characterization of a three-phased chlorine release, a detailed determination of local atmospheric mechanisms acting on the released chlorine, the establishment of atmospheric-hydrological physical exchange mechanisms, and aquatic dilution and mixing. This presentation will provide an overview of the models used in determining the total air-to-water mass transfer estimated to have occurred as a result of the roughly 60 tons of chlorine released into the atmosphere from the train derailment. The assumptions used in the modeling effort will be addressed, along with a comparison with available observational data to validate the model results. Overall, model-estimated chlorine concentrations in the airborne plume compare well with human and animal exposure data collected in the days after the derailment.
Date: May 10, 2011
Creator: Buckley, R.; Hunter, C.; Werth, D.; Chen, K.; Whiteside, M. & Mazzola, C.
Object Type: Article
System: The UNT Digital Library
EMP Attachment 1 DOE-SC PNNL Site Sampling and Analysis Plan (open access)

EMP Attachment 1 DOE-SC PNNL Site Sampling and Analysis Plan

This Sampling and Analysis Plan (SAP) is written for the radiological environmental air surveillance program for the DOE-SC PNNL Site, Richland Washington. It provides the requirements for planning sampling events, and the requirements imposed on the analytical laboratory analyzing the air samples. The actual air sampling process is in procedure EPRP-AIR-029. The rationale for analyte selection, media, and sampling site location has been vetted through the data quality objectives (DQO) process (Barnett et al. 2010). The results from the DQO process have been reviewed and approved by the Washington State Department of Health. The DQO process (Barnett et al. 2010) identified seven specific radionuclides for analysis along with the need for gross alpha and gross beta radiological analyses. The analytes are {sup 241}Am, {sup 243}Am, {sup 244}Cm, {sup 60}Co, {sup 238}Pu, {sup 239}Pu, and {sup 233}U. The report also determined that air samples for particulates are the only sample matrix required for the monitoring program. These samples are collected on 47-mm glass-fiber filters.
Date: November 10, 2011
Creator: Meier, Kirsten M.
Object Type: Report
System: The UNT Digital Library
Injection of large transverse emittance EBIS beams in booster (open access)

Injection of large transverse emittance EBIS beams in booster

During the commissioning of EBIS beams in Booster in November 2010 and in April, May and June 2011, it was found that the transverse emittances of the EBIS beams just upstream of Booster were much larger than expected. Beam emittances of 11{pi} mm milliradians had been expected, but numbers 3 to 4 times larger were measured. Here and throughout this note the beam emittance, {pi}{epsilon}{sub 0}, is taken to be the area of the smallest ellipse that contains 95% of the beam. We call this smallest ellipse the beam ellipse. If the beam distribution is gaussian, the rms emittance of the distribution is very nearly one sixth the area of the beam ellipse. The normalized rms emittance is the rms emittance times the relativistic factor {beta}{gamma} = 0.06564. This amounts to 0.12{pi} mm milliradians for the 11{pi} mm milliradian beam ellipse. In [1] we modeled the injection and turn-by-turn evolution of an 11{pi} mm milliradian beam ellipse in the horizontal plane in Booster. It was shown that with the present injection system, up to 4 turns of this beam could be injected and stored in Booster without loss. In the present note we extend this analysis to the injection of …
Date: October 10, 2011
Creator: Gardner, C.
Object Type: Report
System: The UNT Digital Library
AUTOMATED DEAD-END ULTRAFILTRATION FOR ENHANCED SURVEILLANCE OF LEGIONELLA 2 PNEUMOPHILA AND LEGIONELLA SPP. IN COOLING TOWER WATERS (open access)

AUTOMATED DEAD-END ULTRAFILTRATION FOR ENHANCED SURVEILLANCE OF LEGIONELLA 2 PNEUMOPHILA AND LEGIONELLA SPP. IN COOLING TOWER WATERS

Detection of Legionella pneumophila in cooling towers and domestic hot water systems involves concentration by centrifugation or membrane filtration prior to inoculation onto growth media or analysis using techniques such as PCR or immunoassays. The Portable Multi-use Automated Concentration System (PMACS) was designed for concentrating microorganisms from large volumes of water in the field and was assessed for enhancing surveillance of L. pneumophila at the Savannah River Site, SC. PMACS samples (100 L; n = 28) were collected from six towers between August 2010 and April 2011 with grab samples (500 ml; n = 56) being collected before and after each PMACS sample. All samples were analyzed for the presence of L. pneumophila by direct fluorescence immunoassay (DFA) using FITC-labeled monoclonal antibodies targeting serogroups 1, 2, 4 and 6. QPCR was utilized for detection of Legionella spp. in the same samples. Counts of L. pneumophila from DFA and of Legionella spp. from qPCR were normalized to cells/L tower water. Concentrations were similar between grab and PMACS samples collected throughout the study by DFA analysis (P = 0.4461; repeated measures ANOVA). The same trend was observed with qPCR. However, PMACS concentration proved advantageous over membrane filtration by providing larger volume, more …
Date: October 10, 2011
Creator: Brigmon, R.; Leskinen, S.; Kearns, E.; Jones, W.; Miller, R.; Betivas, C. et al.
Object Type: Article
System: The UNT Digital Library
A Study of Advanced Materials for Gas Turbine Coatings at Elevated Temperatures Using Selected Microstructures and Characteristic Environments for Syngas Combustion (open access)

A Study of Advanced Materials for Gas Turbine Coatings at Elevated Temperatures Using Selected Microstructures and Characteristic Environments for Syngas Combustion

Thermal barrier coatings (TBCs) that can be suitable for use in industrial gas turbine engines have been processed and compared with electron beam physical vapor deposition (EBPVD) microstructures for applications in advanced gas turbines that use coal-derived synthesis gas. Thermo-physical properties have been evaluated of the processed air plasma sprayed TBCs with standard APS-STD and vertically cracked APS-VC coatings samples up to 1300 C. Porosity of these selected coatings with related microstructural effects have been analyzed in this study. Wet and dry thermal cycling studies at 1125 C and spalling resistance thermal cycling studies to 1200 C have also been carried out. Type I and Type II hot corrosion tests were carried out to investigate the effects of microstructure variations and additions of alumina in YSZ top coats in multi-layered TBC structures. The thermal modeling of turbine blade has also been carried out that gives the capability to predict in-service performance temperature gradients. In addition to isothermal high temperature oxidation kinetics analysis in YSZ thermal barrier coatings of NiCoCrAlY bond coats with 0.25% Hf. This can affect the failure behavior depending on the control of the thermally grown oxide (TGO) growth at the interface. The TGO growth kinetics is seen …
Date: February 10, 2011
Creator: Diwan, Ravinder; Mensah, Patrick; Li, Guoqiang; Uppu, Nalini; Akwaboa, Strphen; Silva, Monica et al.
Object Type: Report
System: The UNT Digital Library
Low-Cost Hydrogen Distributed Production System Development (open access)

Low-Cost Hydrogen Distributed Production System Development

H{sub 2}Gen, with the support of the Department of Energy, successfully designed, built and field-tested two steam methane reformers with 578 kg/day capacity, which has now become a standard commercial product serving customers in the specialty metals and PV manufacturing businesses. We demonstrated that this reformer/PSA system, when combined with compression, storage and dispensing (CSD) equipment could produce hydrogen that is already cost-competitive with gasoline per mile driven in a conventional (non-hybrid) vehicle. We further showed that mass producing this 578 kg/day system in quantities of just 100 units would reduce hydrogen cost per mile approximately 13% below the cost of untaxed gasoline per mile used in a hybrid electric vehicle. If mass produced in quantities of 500 units, hydrogen cost per mile in a FCEV would be 20% below the cost of untaxed gasoline in an HEV in the 2015-2020 time period using EIA fuel cost projections for natural gas and untaxed gasoline, and 45% below the cost of untaxed gasoline in a conventional car. This 20% to 45% reduction in fuel cost per mile would accrue even though hydrogen from this 578 kg/day system would cost approximately $4.14/kg, well above the DOE hydrogen cost targets of $2.50/kg by …
Date: March 10, 2011
Creator: C.E. (Sandy) Thomas, Ph.D., President Franklin D. Lomax, Ph.D, CTO & Principal Investigator, and Maxim Lyubovski, Ph.D.
Object Type: Report
System: The UNT Digital Library
SIMULATION OF THE ICELAND VOLCANIC ERUPTION OF APRIL 2010 USING THE ENSEMBLE SYSTEM (open access)

SIMULATION OF THE ICELAND VOLCANIC ERUPTION OF APRIL 2010 USING THE ENSEMBLE SYSTEM

The Eyjafjallajokull volcanic eruption in Iceland in April 2010 disrupted transportation in Europe which ultimately affected travel plans for many on a global basis. The Volcanic Ash Advisory Centre (VAAC) is responsible for providing guidance to the aviation industry of the transport of volcanic ash clouds. There are nine such centers located globally, and the London branch (headed by the United Kingdom Meteorological Office, or UKMet) was responsible for modeling the Iceland volcano. The guidance provided by the VAAC created some controversy due to the burdensome travel restrictions and uncertainty involved in the prediction of ash transport. The Iceland volcanic eruption provides a useful exercise of the European ENSEMBLE program, coordinated by the Joint Research Centre (JRC) in Ispra, Italy. ENSEMBLE, a decision support system for emergency response, uses transport model results from a variety of countries in an effort to better understand the uncertainty involved with a given accident scenario. Model results in the form of airborne concentration and surface deposition are required from each member of the ensemble in a prescribed format that may then be uploaded to a website for manipulation. The Savannah River National Laboratory (SRNL) is the lone regular United States participant throughout the 10-year …
Date: May 10, 2011
Creator: Buckley, R.
Object Type: Article
System: The UNT Digital Library
Simulation of free-electron lasers seeded with broadband radiation (open access)

Simulation of free-electron lasers seeded with broadband radiation

The longitudinal coherence of free-electron laser (FEL) radiation can be enhanced by seeding the FEL with high harmonics of an optical laser pulse. The radiation produced by high-harmonic generation (HHG), however, has a fast-varying temporal profile that can violate the slowly varying envelope approximation and limited frequency window that is employed in conventional free-electron laser simulation codes. Here we investigate the implications of violating this approximation on the accuracy of simulations. On the basis of both analytical considerations and 1D numerical studies, it is concluded that, for most realistic scenarios, conventional FEL codes are capable of accurately simulating the FEL process even when the seed radiation violates the slowly varying envelope approximation. We additionally discuss the significance of filtering the harmonic content of broadband HHG seeds.
Date: March 10, 2011
Creator: Bajlekov, Svetoslav; Fawley, William; Schroeder, Carl; Bartolini, Riccardo & Hooker, Simon
Object Type: Article
System: The UNT Digital Library
Overview of the Facility Safeguardability Analysis (FSA) Process (open access)

Overview of the Facility Safeguardability Analysis (FSA) Process

The safeguards system of the International Atomic Energy Agency (IAEA) provides the international community with credible assurance that a State is fulfilling its nonproliferation obligations. The IAEA draws such conclusions from the evaluation of all available information. Effective and cost-efficient IAEA safeguards at the facility level are, and will remain, an important element of this “State-level” approach. Efficiently used, the Safeguards by Design (SBD) methodologies , , , now being developed can contribute to effective and cost-efficient facility-level safeguards. The Facility Safeguardability Assessment (FSA) introduced here supports SBD in three areas. 1. It describes necessary interactions between the IAEA, the State regulator, and the owner / designer of a new or modified facility to determine where SBD efforts can be productively applied, 2. It presents a screening approach intended to identify potential safeguard issues for; a) design changes to existing facilities; b) new facilities similar to existing facilities with approved safeguards approaches, and c) new designs, 3. It identifies resources (the FSA toolkit), such as good practice guides, design guidance, and safeguardability evaluation methods that can be used by the owner/designer to develop solutions for potential safeguards issues during the interactions with the State regulator and IAEA. FSA presents a …
Date: October 10, 2011
Creator: Bari, Robert A.; Hockert, John; Wonder, Edward F.; Johnson, Shirley J.; Wigeland, Roald & Zentner, Michael D.
Object Type: Report
System: The UNT Digital Library
Actinic characterization of EUV bump-type phase defects (open access)

Actinic characterization of EUV bump-type phase defects

Despite tremendous progress and learning with EUV lithography, quantitative experimental information about the severity of point-like phase defects remains in short supply. We present a study of measured, EUV aerial images from a series of well-characterized, open-field, bump-type programmed phase defects, created on a substrate before multilayer deposition.
Date: January 10, 2011
Creator: Goldberg, Kenneth A.; Mochi, Iacopo & Liang, Ted
Object Type: Article
System: The UNT Digital Library
Improvement of snowpack simulations in a regional climate model (open access)

Improvement of snowpack simulations in a regional climate model

To improve simulations of regional-scale snow processes and related cold-season hydroclimate, the Community Land Model version 3 (CLM3), developed by the National Center for Atmospheric Research (NCAR), was coupled with the Pennsylvania State University/NCAR fifth-generation Mesoscale Model (MM5). CLM3 physically describes the mass and heat transfer within the snowpack using five snow layers that include liquid water and solid ice. The coupled MM5–CLM3 model performance was evaluated for the snowmelt season in the Columbia River Basin in the Pacific Northwestern United States using gridded temperature and precipitation observations, along with station observations. The results from MM5–CLM3 show a significant improvement in the SWE simulation, which has been underestimated in the original version of MM5 coupled with the Noah land-surface model. One important cause for the underestimated SWE in Noah is its unrealistic land-surface structure configuration where vegetation, snow and the topsoil layer are blended when snow is present. This study demonstrates the importance of the sheltering effects of the forest canopy on snow surface energy budgets, which is included in CLM3. Such effects are further seen in the simulations of surface air temperature and precipitation in regional weather and climate models such as MM5. In addition, the snow-season surface albedo …
Date: January 10, 2011
Creator: Jin, J. & Miller, N. L.
Object Type: Article
System: The UNT Digital Library
Element-specific study of epitaxial NiO/Ag/CoO/Fe films grown on vicinal Ag(001) using photoemission electron microscopy (open access)

Element-specific study of epitaxial NiO/Ag/CoO/Fe films grown on vicinal Ag(001) using photoemission electron microscopy

NiO/Ag/CoO/Fe single crystalline films are grown epitaxially on a vicinal Ag(001) substrate using molecular beam epitaxy and investigated by photoemission electron microscopy. We find that after zero-field cooling, the in-plane Fe magnetization switches from parallel to perpendicular direction of the atomic steps of the vicinal surface at thinner CoO thickness but remains in its original direction parallel to the steps at thicker CoO thickness. CoO and NiO domain imaging result shows that both CoO/Fe and NiO/CoO spins are perpendicularly coupled, suggesting that the Fe magnetization switching may be associated with the rotatable-frozen spin transition of the CoO film.
Date: January 10, 2011
Creator: Meng, Y.; Li, J.; Tan, A.; Jin, E.; Son, J.; Park, J. S. et al.
Object Type: Article
System: The UNT Digital Library
Analysis of International Policies In The Solar Electricity Sector: Lessons for India (open access)

Analysis of International Policies In The Solar Electricity Sector: Lessons for India

Although solar costs are dropping rapidly, solar power is still more expensive than conventional and other renewable energy options. The solar sector still needs continuing government policy support. These policies are driven by objectives that go beyond the goal of achieving grid parity. The need to achieve multiple objectives and ensure sufficient political support for solar power makes it diffi cult for policy makers to design the optimal solar power policy. The dynamic and uncertain nature of the solar industry, combined with the constraints offered by broader economic, political and social conditions further complicates the task of policy making. This report presents an analysis of solar promotion policies in seven countries - Germany, Spain, the United States, Japan, China, Taiwan, and India - in terms of their outlook, objectives, policy mechanisms and outcomes. The report presents key insights, primarily in qualitative terms, and recommendations for two distinct audiences. The first audience consists of global policy makers who are exploring various mechanisms to increase the penetration of solar power in markets to mitigate climate change. The second audience consists of key Indian policy makers who are developing a long-term implementation plan under the Jawaharlal Nehru National Solar Mission and various state …
Date: August 10, 2011
Creator: Deshmukh, Ranjit; Bharvirkar, Ranjit; Gambhir, Ashwin & Phadke, Amol
Object Type: Report
System: The UNT Digital Library
Sheet beam model for intense space-charge: with application to Debye screening and the distribution of particle oscillation frequencies in a thermal equilibrium beam (open access)

Sheet beam model for intense space-charge: with application to Debye screening and the distribution of particle oscillation frequencies in a thermal equilibrium beam

A one-dimensional Vlasov-Poisson model for sheet beams is reviewed and extended to provide a simple framework for analysis of space-charge effects. Centroid and rms envelope equations including image charge effects are derived and reasonable parameter equivalences with commonly employed 2D transverse models of unbunched beams are established. This sheet beam model is then applied to analyze several problems of fundamental interest. A sheet beam thermal equilibrium distribution in a continuous focusing channel is constructed and shown to have analogous properties to two- d three-dimensional thermal equilibrium models in terms of the equilibrium structure and Deybe screening properties. The simpler formulation for sheet beams is exploited to explicitly calculate the distribution of particle oscillation frequencies within a thermal equilibrium beam. It is shown that as space-charge intensity increases, the frequency distribution becomes broad, suggesting that beams with strong space-charge can have improved stability.
Date: January 10, 2011
Creator: Lund, Steven M.; Friedman, Alex & Bazouin, Guillaume
Object Type: Article
System: The UNT Digital Library
Camera assembly design proposal for SRF cavity image collection (open access)

Camera assembly design proposal for SRF cavity image collection

This project seeks to collect images from the inside of a superconducting radio frequency (SRF) large grain niobium cavity during vertical testing. These images will provide information on multipacting and other phenomena occurring in the SRF cavity during these tests. Multipacting, a process that involves an electron buildup in the cavity and concurrent loss of RF power, is thought to be occurring near the cathode in the SRF structure. Images of electron emission in the structure will help diagnose the source of multipacting in the cavity. Multipacting sources may be eliminated with an alteration of geometric or resonant conditions in the SRF structure. Other phenomena, including unexplained light emissions previously discovered at SLAC, may be present in the cavity. In order to effectively capture images of these events during testing, a camera assembly needs to be installed to the bottom of the RF structure. The SRF assembly operates under extreme environmental conditions: it is kept in a dewar in a bath of 2K liquid helium during these tests, is pumped down to ultra-high vacuum, and is subjected to RF voltages. Because of this, the camera needs to exist as a separate assembly attached to the bottom of the cavity. The …
Date: October 10, 2011
Creator: Tuozzolo, S.
Object Type: Report
System: The UNT Digital Library
Printability and inspectability of Defects on the EUV Mask for sub32nm Half Pitch HVM Application (open access)

Printability and inspectability of Defects on the EUV Mask for sub32nm Half Pitch HVM Application

The availability of defect-free masks remains one of the key challenges for inserting extreme ultraviolet lithography (EUVL) into high volume manufacturing, yet little data is available for understanding native defects on real masks. In this paper, a full field EUV mask is fabricated to see the printability of various defects on the mask. Programmed pit defect shows that minimum printable size of pits could be 17 nm of SEVD from the AIT. However 23.1nm in SEVD is printable from the EUV ADT. Defect printability and identification of its source along from blank fabrication to mask fabrication were studied using various inspection tools. Capture ratio of smallest printable defects was improved to 80% using optimized stack of metrical on wafer and state-of-art wafer inspection tool. Requirement of defect mitigation technology using fiducial mark are defined.
Date: January 10, 2011
Creator: Huh, S.; Kang, I. Y.; Kim, S. H.; Seo, H. S.; Kim, D.; Park, J. et al.
Object Type: Article
System: The UNT Digital Library
DNA Extraction by Isotachophoresis in a Microfluidic Channel (open access)

DNA Extraction by Isotachophoresis in a Microfluidic Channel

Biological assays have many applications. For example, forensics personnel and medical professionals use these tests to diagnose diseases and track their progression or identify pathogens and the host response to them. One limitation of these tests, however, is that most of them target only one piece of the sample - such as bacterial DNA - and other components (e.g. host genomic DNA) get in the way, even though they may be useful for different tests. To address this problem, it would be useful to extract several different substances from a complex biological sample - such as blood - in an inexpensive and efficient manner. This summer, I worked with Maxim Shusteff at Lawrence Livermore National Lab on the Rapid Automated Sample Prep project. The goal of the project is to solve the aforementioned problem by creating a system that uses a series of different extraction methods to extract cells, bacteria, and DNA from a complex biological sample. Biological assays can then be run on purified output samples. In this device, an operator could input a complex sample such as blood or saliva, and would receive separate outputs of cells, bacteria, viruses, and DNA. I had the opportunity to work this …
Date: August 10, 2011
Creator: Stephenson, S J
Object Type: Report
System: The UNT Digital Library

[Business Leadership Building interior lounge]

Photograph of the interior of the Business Leadership Building where seating and a cafe are open to students. There are plants next to the columns and students are seated around tables.
Date: November 10, 2011
Creator: unknown
Object Type: Photograph
System: The UNT Digital Library
Muon Collider Progress: Accelerators (open access)

Muon Collider Progress: Accelerators

A muon collider would be a powerful tool for exploring the energy-frontier with leptons, and would complement the studies now under way at the LHC. Such a device would offer several important benefits. Muons, like electrons, are point particles so the full center-of-mass energy is available for particle production. Moreover, on account of their higher mass, muons give rise to very little synchrotron radiation and produce very little beamstrahlung. The first feature permits the use of a circular collider that can make efficient use of the expensive rf system and whose footprint is compatible with an existing laboratory site. The second feature leads to a relatively narrow energy spread at the collision point. Designing an accelerator complex for a muon collider is a challenging task. Firstly, the muons are produced as a tertiary beam, so a high-power proton beam and a target that can withstand it are needed to provide the required luminosity of ~1 × 10{sup 34} cm{sup –2}s{sup –1}. Secondly, the beam is initially produced with a large 6D phase space, which necessitates a scheme for reducing the muon beam emittance (“cooling”). Finally, the muon has a short lifetime so all beam manipulations must be done very rapidly. …
Date: September 10, 2011
Creator: Zisman, Michael S.
Object Type: Article
System: The UNT Digital Library
Numerical Model for Conduction-Cooled Current Lead Heat Loads (open access)

Numerical Model for Conduction-Cooled Current Lead Heat Loads

Current leads are utilized to deliver electrical power from a room temperature junction mounted on the vacuum vessel to a superconducting magnet located within the vacuum space of a cryostat. There are many types of current leads used at laboratories throughout the world; however, conduction-cooled current leads are often chosen for their simplicity and reliability. Conduction-cooled leads have the advantage of using common materials, have no superconducting/normal state transition, and have no boil-off vapor to collect. This paper presents a numerical model for conduction-cooled current lead heat loads. This model takes into account varying material and fluid thermal properties, varying thicknesses along the length of the lead, heat transfer in the circumferential and longitudinal directions, electrical power dissipation, and the effect of thermal intercepts. The model is validated by comparing the numerical model results to ideal cases where analytical equations are valid. In addition, the XFEL (X-Ray Free Electron Laser) prototype current leads are modeled and compared to the experimental results from testing at DESY's XFEL Magnet Test Stand (XMTS) and Cryomodule Test Bench (CMTB).
Date: June 10, 2011
Creator: White, M. J.; Wang, X. L. & Brueck, H. D.
Object Type: Article
System: The UNT Digital Library
Vibrational Spectroscopy of Chromatographic Interfaces (open access)

Vibrational Spectroscopy of Chromatographic Interfaces

Chromatographic separations play a central role in DOE-supported fundamental research related to energy, biological systems, the environment, and nuclear science. The overall portfolio of research activities in the Separations and Analysis Program within the DOE Office of Basic Energy Sciences includes support for activities designed to develop a molecular-level understanding of the chemical processes that underlie separations for both large-scale and analytical-scale purposes. The research effort funded by this grant award was a continuation of DOE-supported research to develop vibrational spectroscopic methods to characterize the interfacial details of separations processes at a molecular level.
Date: March 10, 2011
Creator: Pemberton, Jeanne E.
Object Type: Report
System: The UNT Digital Library
Minimal Simple de Sitter Solutions (open access)

Minimal Simple de Sitter Solutions

None
Date: November 10, 2011
Creator: Haque, Sheikh Shajidul; Shiu, Gary; Underwood, Bret & Van Riet, Thomas
Object Type: Article
System: The UNT Digital Library