Language

A study of tau decays of the W boson at CDF (Collider Detector at Fermilab) (open access)

A study of tau decays of the W boson at CDF (Collider Detector at Fermilab)

A report is given of a search for tau decays of the W boson in p{bar p} collisions at {radical}s = 1.8 TeV using the Collider Detector at Fermilab (CDF). A description of a hardware trigger specifically designed to enhance the number of events with tau decays is presented along with the results of a preliminary analysis of data taken during the 1988--89 run of CDF. 10 refs., 4 figs.
Date: January 3, 1990
Creator: Gladney, L. D.
Object Type: Article
System: The UNT Digital Library
Solar energy school heating augmentation experiment. Sections I, II, and III. ITC report No. 281076 (open access)

Solar energy school heating augmentation experiment. Sections I, II, and III. ITC report No. 281076

The Fauquier High School Solar Heating System utilizes a solar collector array of 2415 square feet active area. The collectors are mounted in a single plane which is tilted at a 53/sup 0/ angle from the horizontal. The latitude of Warrenton, Virginia is 38.6/sup 0/. Thermal storage is provided by water stored in two concrete tanks, each of 5500 gallon capacity. The tanks are insulated with 4'' of polyurethane and have a temperature loss of 1/sup 0/F per day at a temperature of 140/sup 0/F. Piping to the tanks is arranged so they can be used separately for maximum efficiency. A drain-down mode is used to provide freeze protection for the collectors. No antifreeze is used in the system. There are no heat exchangers in the system except for the classrooms where two water--air convectors are used for space heating. The convectors are equipped with a two speed fan and are sized to provide the heating requirements of the classrooms with 100/sup 0/F water storage temperatures. Back-up heating is provided with the electric resistance heaters originally installed in the classrooms. One classroom has, in addition, an oil heater. The operation, performance, maintenance, and modifications to the system over the 1974-75 …
Date: January 3, 1977
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Meeting Record for FFA Working Meeting of November 15, 1991 (open access)

Meeting Record for FFA Working Meeting of November 15, 1991

This document provides a meeting record of the Federal Facility Agreement (FFA) working meeting to discuss progress on old issues and further required actions regarding environmental impacts of the Savannah River Facility. (FI)
Date: January 3, 1992
Creator: Stejskal, G. F.
Object Type: Report
System: The UNT Digital Library
Soft X-ray synchrotron radiation investigations of actinidematerials systems utilizing X-ray emission spectroscopy and resonantinelastic X-ray scattering (open access)

Soft X-ray synchrotron radiation investigations of actinidematerials systems utilizing X-ray emission spectroscopy and resonantinelastic X-ray scattering

Synchrotron radiation (SR) methods have been utilized with increasing frequency over the past several years to study topics in actinide science, ranging from those of a fundamental nature to those that address a specifically-targeted technical need. In particular, the emergence of microspectroscopic and fluorescence-based techniques have permitted investigations of actinide materials at sources of soft x-ray SR. Spectroscopic techniques with fluorescence-based detection are useful for actinide investigations since they are sensitive to small amounts of material and the information sampling depth may be varied. These characteristics also serve to simplify both sample preparation and safety considerations. Examples of investigations using these fluorescence techniques will be described along with their results, as well as the prospects for future investigations utilizing these methodologies.
Date: January 3, 2004
Creator: Shuh, D.K.; Butorin, S.M.; Guo, J.-H. & Nordgren, J.
Object Type: Article
System: The UNT Digital Library
APTASENSORS FOR BIOSECURITY APPLICATIONS (open access)

APTASENSORS FOR BIOSECURITY APPLICATIONS

Nucleic acid aptamers have found steadily increased utility and application steadily over the last decade. In particular, aptamers have been touted as a valuable complement to and in some cases replacement for antibodies due to their structural and functional robustness as well as their ease in generation and synthesis. They are thus attractive for biosecurity applications, e.g. pathogen detection, and are especially well suited since their in vitro generation process does not require infection of any host systems. Herein we provide a brief overview of the aptamers generated against biopathogens over the last few years. In addition, a few recently described detection platforms using aptamers (aptasensors) and potentially suitable for biosecurity applications will be discussed.
Date: January 3, 2007
Creator: Fischer, N; Tarasow, T & Tok, J
Object Type: Article
System: The UNT Digital Library
Sub-diffraction-limited multilayer coatings for the 0.3-NA Micro-Exposure Tool for extreme ultraviolet lithography (open access)

Sub-diffraction-limited multilayer coatings for the 0.3-NA Micro-Exposure Tool for extreme ultraviolet lithography

This manuscript discusses the multilayer coating results for the primary and secondary mirrors of the Micro Exposure Tool (MET): a 0.30-numerical aperture (NA) lithographic imaging system with 200 x 600 {micro}m{sup 2} field of view at the wafer plane, operating in the extreme ultraviolet (EUV) wavelength region. Mo/Si multilayers were deposited by DC-magnetron sputtering on large-area, curved MET camera substrates, and a velocity modulation technique was implemented to consistently achieve multilayer thickness profiles with added figure errors below 0.1 nm rms to achieve sub-diffraction-limited performance. This work represents the first experimental demonstration of sub-diffraction-limited multilayer coatings for high-NA EUV imaging systems.
Date: January 3, 2007
Creator: Soufli, R.; Hudyma, R. M.; Spiller, E.; Gullikson, E. M.; Schmidt, M. A.; Robinson, J. C. et al.
Object Type: Article
System: The UNT Digital Library
Tracking Multiple Topics for Finding Interesting Articles (open access)

Tracking Multiple Topics for Finding Interesting Articles

We introduce multiple topic tracking (MTT) for iScore to better recommend news articles for users with multiple interests and to address changes in user interests over time. As an extension of the basic Rocchio algorithm, traditional topic detection and tracking, and single-pass clustering, MTT maintains multiple interest profiles to identify interesting articles for a specific user given user-feedback. Focusing on only interesting topics enables iScore to discard useless profiles to address changes in user interests and to achieve a balance between resource consumption and classification accuracy. iScore is able to achieve higher quality results than traditional methods such as the Rocchio algorithm. We identify several operating parameters that work well for MTT. Using the same parameters, we show that MTT alone yields high quality results for recommending interesting articles from several corpora. The inclusion of MTT improves iScore's performance by 25% in recommending news articles from the Yahoo! News RSS feeds and the TREC11 adaptive filter article collection. And through a small user study, we show that iScore can still perform well when only provided with little user feedback.
Date: January 3, 2008
Creator: Pon, R K; Cardenas, A F; Buttler, D J & Critchlow, T J
Object Type: Report
System: The UNT Digital Library
Explosively driven facture and fragmentation of metal cylinders and rings (open access)

Explosively driven facture and fragmentation of metal cylinders and rings

Cylinders and rings fabricated from AerMet{reg_sign} 100 alloy and AISI 1018 steel have been explosively driven to fragmentation in order to determine the fracture strains for these materials under plane strain and uniaxial stress conditions. The phenomena associated with the dynamic expansion and subsequent break up of the cylinders are monitored with high-speed diagnostics. In addition, complementary experiments are performed in which fragments from the explosively driven cylinder are recovered and analyzed to determine the statistical distribution associated with the fragmentation process as well as to determine failure mechanisms. The data are used to determine relevant coefficients for the Johnson-Cook (Hancock-McKenzie) fracture model. Metallurgical analysis of the fragments provides information on damage and failure mechanisms.
Date: January 3, 2007
Creator: Goto, D; Becker, R C; Orzechowski, T J; Springer, H K; Sunwoo, A J & Syn, C K
Object Type: Article
System: The UNT Digital Library
Human Health and Ecological Risk Assessment for the Operation of the Explosives Waste Treatment Facility at Site 300 of the Lawrence Livermore National Laboratory Volume 1: Report of Results (open access)
Microscopic Theory of Fission (open access)

Microscopic Theory of Fission

None
Date: January 3, 2008
Creator: Younes, W & Gogny, D
Object Type: Article
System: The UNT Digital Library
Electronic Structure of zinc-blende AlxGa1-xN; Screened-ExchangeStudy (open access)

Electronic Structure of zinc-blende AlxGa1-xN; Screened-ExchangeStudy

We present a first principle investigation of the electronicstructure and the band gap bowing parameter of zinc-blende \AlGaN usingboth local density approximation and screened-exchange density functionalmethod. The calculated sX-LDA band gaps for GaN and AlN are 95 percentand 90 percent of the experimentally observed values, respectively, whileLDA under estimates the gaps to 62 percent and 70 percent. In contrast tothe gap itself, the band gap bowing parameter is found to be very similarin sX-LDA and LDA. Because of the difference in the conduction bandstructure, the direct to indirect band gap crossover is predicted tooccur at different Al concentration.
Date: January 3, 2006
Creator: Lee, Byounghak & Wang, Lin-Wang
Object Type: Article
System: The UNT Digital Library
Evaluated Decay Data for 206TI. (open access)

Evaluated Decay Data for 206TI.

Evaluated decay data for the {sup 206}Tl nuclide are presented, including recommended values for the half-life, {beta}- and {gamma}-ray emission energies and probabilities. Data on X-ray radiations, Auger and conversion electron energies and emission probabilities are also tabulated. Carefully evaluated data for radioactive nuclides refer to complex nuclear level schemes and tables of numerical values, which quantify fundamental nuclear structure information such as level energies and quantum numbers, lifetimes, decay modes, and other associated properties. These data are not only at the core of basic nuclear structure and nuclear astrophysics research, but they are also relevant to many applied technologies, including nuclear energy production, reactor design and safety, medical diagnostic and radiotherapy, health physics, environmental research and monitoring, safeguards and material analysis. The evaluation process results in numerous sets of recommended values on half-lives, radiation energies and emission probabilities. The work on evaluation of decay properties of {sup 206}Tl was completed in September 2006 with a literature cut off by the same date. The Saisinuc software (2002BeXX) and associated supporting programs were used in assembling the data following the established protocol within the International Decay Data Evaluation Project (DDEP) collaboration.
Date: January 3, 2007
Creator: Kondev, F. G.
Object Type: Report
System: The UNT Digital Library
Demand Responsive Lighting: A Scoping Study (open access)

Demand Responsive Lighting: A Scoping Study

The objective of this scoping study is: (1) to identify current market drivers and technology trends that can improve the demand responsiveness of commercial building lighting systems and (2) to quantify the energy, demand and environmental benefits of implementing lighting demand response and energy-saving controls strategies Statewide. Lighting systems in California commercial buildings consume 30 GWh. Lighting systems in commercial buildings often waste energy and unnecessarily stress the electrical grid because lighting controls, especially dimming, are not widely used. But dimmable lighting equipment, especially the dimming ballast, costs more than non-dimming lighting and is expensive to retrofit into existing buildings because of the cost of adding control wiring. Advances in lighting industry capabilities coupled with the pervasiveness of the Internet and wireless technologies have led to new opportunities to realize significant energy saving and reliable demand reduction using intelligent lighting controls. Manufacturers are starting to produce electronic equipment--lighting-application specific controllers (LAS controllers)--that are wirelessly accessible and can control dimmable or multilevel lighting systems obeying different industry-accepted protocols. Some companies make controllers that are inexpensive to install in existing buildings and allow the power consumed by bi-level lighting circuits to be selectively reduced during demand response curtailments. By intelligently limiting the …
Date: January 3, 2007
Creator: Rubinstein, Francis & Kiliccote, Sila
Object Type: Report
System: The UNT Digital Library
TASK TECHNICAL AND QUALITY ASSURANCE PLAN FOR GAMMA ASSAYS AT THE SRS SOLID WASTE MANAGEMENT FACILITIES (open access)

TASK TECHNICAL AND QUALITY ASSURANCE PLAN FOR GAMMA ASSAYS AT THE SRS SOLID WASTE MANAGEMENT FACILITIES

None
Date: January 3, 2006
Creator: CASELLA, VITO
Object Type: Report
System: The UNT Digital Library
Correspondence of the Gardner and van Genuchten/Mualem relativepermeability function parameters (open access)

Correspondence of the Gardner and van Genuchten/Mualem relativepermeability function parameters

The Gardner and van Genuchten models of relativepermeability are widely used in analytical and numerical solutions toflow problems. However, the applicab ility of the Gardner model to realproblems is usually limited, because empirical relative permeability datato calibrate the model are not routinely available. In contrast, vanGenuchten parameters can be estimated using more routinely availablematric potential and saturation data. However, the van Genuchten model isnot amenable to analytical solutions. In this paper, we introducegeneralized conversion formulae that reconcile these two models. Ingeneral, we find that the Gardner parameter alpha G is related to the vanGenuchten parameters alpha vG and n by alpha G=alpha vG ~; 1:3 n. Thisconversion rule will allow direct recasting of Gardner-based analyticalsolutions in the van Genuchten parameter space. The validity of theproposed formulae was tested by comparing the predicted relativepermeability of various porous media with measured values.
Date: January 3, 2007
Creator: Ghezzehei, Teamrat A.; Kneafsey, Timothy J. & Su, Grace W.
Object Type: Article
System: The UNT Digital Library
Nanoscale Synthesis and Characterization Laboratory Annual Report 2005 (open access)

Nanoscale Synthesis and Characterization Laboratory Annual Report 2005

The Nanoscale Synthesis and Characterization Laboratory's (NSCL) primary mission is to create and advance interdisciplinary research and development opportunities in nanoscience and technology. The initial emphasis of the NSCL has been on development of scientific solutions in support of target fabrication for the NIF laser and other stockpile stewardship experimental platforms. Particular emphasis has been placed on the design and development of innovative new materials and structures for use in these targets. Projects range from the development of new high strength nanocrystalline alloys to graded density materials to high Z nanoporous structures. The NSCL also has a mission to recruit and train personnel for Lab programs such as the National Ignition Facility (NIF), Defense and Nuclear Technologies (DNT), and Nonproliferation, Arms control and International security (NAI). The NSCL continues to attract talented scientists to the Laboratory.
Date: January 3, 2006
Creator: Hamza, A V & Lesuer, D R
Object Type: Report
System: The UNT Digital Library
Electrical and Optical Gain Lever Effects in InGaAs Double Quantum Well Diode Lasers (open access)

Electrical and Optical Gain Lever Effects in InGaAs Double Quantum Well Diode Lasers

In multisection laser diodes, the amplitude or frequency modulation (AM or FM) efficiency can be improved using the gain lever effect. To study gain lever, InGaAs double quantum well (DQW) edge emitting lasers have been fabricated with integrated passive waveguides and dual sections providing a range of split ratios from 1:1 to 9:1. Both the electrical and the optical gain lever have been examined. An electrical gain lever with greater than 7 dB enhancement of AM efficiency was achieved within the range of appropriate DC biasing currents, but this gain dropped rapidly outside this range. We observed a 4 dB gain in the optical AM efficiency under non-ideal biasing conditions. This value agreed with the measured gain for the electrical AM efficiency under similar conditions. We also examined the gain lever effect under large signal modulation for digital logic switching applications. To get a useful gain lever for optical gain quenched logic, a long control section is needed to preserve the gain lever strength and a long interaction length between the input optical signal and the lasing field of the diode must be provided. The gain lever parameter space has been fully characterized and validated against numerical simulations of a …
Date: January 3, 2007
Creator: Pocha, M D; Goddard, L L; Bond, T C; Nikolic, R J; Vernon, S P; Kallman, J S et al.
Object Type: Article
System: The UNT Digital Library
Isopiestic Determination of the Osmotic and Activity Coefficients of Li2SO4(aq) at T = 298.15 and 323.15 K, and Representation with an Extended Ion-interaction (Pitzer) model (open access)

Isopiestic Determination of the Osmotic and Activity Coefficients of Li2SO4(aq) at T = 298.15 and 323.15 K, and Representation with an Extended Ion-interaction (Pitzer) model

Isopiestic vapor-pressure measurements were made for Li{sub 2}SO{sub 4}(aq) from 0.1069 to 2.8190 mol {center_dot} kg{sup -1} at 298.15 K, and from 0.1148 to 2.7969 mol {center_dot} kg{sup -1} at 323.15 K, with NaCl(aq) as the reference standard. Published thermodynamic data for this system were reviewed, recalculated for consistency, and critically assessed. The present results and the more reliable published results were used to evaluate the parameters of an extended version of Pitzer's ion-interaction model with an ionic-strength dependent third virial coefficient, as well as those of the standard Pitzer model, for the osmotic and activity coefficients at both temperatures. Published enthalpies of dilution at 298.15 K were also analyzed to yield the parameters of the ion-interaction models for the relative apparent molar enthalpies of dilution. The resulting models at 298.15 K are valid to the saturated solution molality of the thermodynamically stable phase Li{sub 2}SO{sub 4} {center_dot} H{sub 2}O(cr). Solubilities of Li{sub 2}SO{sub 4} {center_dot} H{sub 2}O(cr) at 298.15 K were assessed, and the selected value of m(sat.) = 3.13 {+-} 0.04 mol {center_dot} kg{sup -1} was used to evaluate the thermodynamic solubility product K{sub s}(Li{sub 2}SO{sub 4} {center_dot} H{sub 2}O, cr, 298.15 K) = (2.62 {+-} 0.19) and …
Date: January 3, 2007
Creator: Rard, J A; Clegg, S L & Palmer, D A
Object Type: Article
System: The UNT Digital Library
Results of Large-Scale Testing on Effects of Anti-Foam Agent on Gas Retention and Release (open access)

Results of Large-Scale Testing on Effects of Anti-Foam Agent on Gas Retention and Release

The U.S. Department of Energy (DOE) Office of River Protection’s Waste Treatment Plant (WTP) will process and treat radioactive waste that is stored in tanks at the Hanford Site. The waste treatment process in the pretreatment facility will mix both Newtonian and non-Newtonian slurries in large process tanks. Process vessels mixing non-Newtonian slurries will use pulse jet mixers (PJMs), air sparging, and recirculation pumps. An anti-foam agent (AFA) will be added to the process streams to prevent surface foaming, but may also increase gas holdup and retention within the slurry. The work described in this report addresses gas retention and release in simulants with AFA through testing and analytical studies. Gas holdup and release tests were conducted in a 1/4-scale replica of the lag storage vessel operated in the Pacific Northwest National Laboratory (PNNL) Applied Process Engineering Laboratory using a kaolin/bentonite clay and AZ-101 HLW chemical simulant with non-Newtonian rheological properties representative of actual waste slurries. Additional tests were performed in a small-scale mixing vessel in the PNNL Physical Sciences Building using liquids and slurries representing major components of typical WTP waste streams. Analytical studies were directed at discovering how the effect of AFA might depend on gas composition and …
Date: January 3, 2008
Creator: Stewart, Charles W.; Guzman-Leong, Consuelo E.; Arm, Stuart T.; Butcher, Mark G.; Golovich, Elizabeth C.; Jagoda, Lynette K. et al.
Object Type: Report
System: The UNT Digital Library
Large-scale quantum mechanical simulations of high-Z metals (open access)

Large-scale quantum mechanical simulations of high-Z metals

High-Z metals constitute a particular challenge for large-scale ab initio calculations, as they require high resolution due to the presence of strongly localized states and require many eigenstates to be computed due to the large number of electrons and need to accurately resolve the Fermi surface. Here, we report recent findings on high-Z materials, using an efficient massively parallel planewave implementation on some of the largest computational architectures currently available. We discuss the particular architectures employed and methodological advances required to harness them effectively. We present a pair-correlation function for U, calculated using quantum molecular dynamics, and discuss relaxations of Pu atoms in the vicinity of defects in aged and alloyed Pu. We find that the self-irradiation associated with aging has a negligible effect on the compressibility of Pu relative to other factors such as alloying.
Date: January 3, 2007
Creator: Yang, L H; Hood, R; Pask, J & Klepeis, J
Object Type: Article
System: The UNT Digital Library
TREATMENT TESTS FOR EX SITU REMOVAL OF CHROMATE & NITRATE & URANIUM (VI) FROM HANFORD (100-HR-3) GROUNDWATER FINAL REPORT (open access)

TREATMENT TESTS FOR EX SITU REMOVAL OF CHROMATE & NITRATE & URANIUM (VI) FROM HANFORD (100-HR-3) GROUNDWATER FINAL REPORT

This report describes batch and ion exchange column laboratory scale studies investigating ex situ methods to remove chromate (chromium [VI]), nitrate (NO{sub 3}{sup -}) and uranium (present as uranium [VI]) from contaminated Hanford site groundwaters. The technologies investigated include: chemical precipitation or coprecipitation to remove chromate and uranium; and anion exchange to remove chromate, uranium and nitrate. The technologies investigated were specified in the 100-HR-3 Groundwater Treatability Test Plan. The method suggested for future study is anion exchange.
Date: January 3, 1994
Creator: MA, BECK & JB, DUNCAN
Object Type: Report
System: The UNT Digital Library
Nanoparticle Based Surface-Enhanced Raman Spectroscopy (open access)

Nanoparticle Based Surface-Enhanced Raman Spectroscopy

Surface-enhanced Raman scattering is a powerful tool for the investigation of biological samples. Following a brief introduction to Raman and surface-enhanced Raman scattering, several examples of biophotonic applications of SERS are discussed. The concept of nanoparticle based sensors using SERS is introduced and the development of these sensors is discussed.
Date: January 3, 2005
Creator: Talley, Chad E.; Huser, Thomas R.; Hollars, Christopher W.; Jusinski, Leonard; Laurence, Ted & Lane, Stephen M.
Object Type: Article
System: The UNT Digital Library
Photoelectron Diffraction of Magnetic Ultrathin Films: Fe/Cu(001) (open access)

Photoelectron Diffraction of Magnetic Ultrathin Films: Fe/Cu(001)

The preliminary results of an ongoing investigation of Fe/Cu(001) are presented here. Energy dependent photoelectron diffraction, including the spin-dependent variant using the multiplet split Fe3s state, is being used to investigate the nanoscale structures formed by near-monolayer deposits of Fe onto Cu(001). Core-level photoemission from the Fe3p and Fe3s states has been generated using synchrotron radiation as the tunable excitation source. Tentatively, a comparison of the experimental Fe3p cross section measurements with multiple scattering calculations indicates that the Fe is in a fourfold hollow site with a spacing of 3.6{Angstrom} between it and the atom directly beneath it, in the third layer. This is consistent with an FCC structure. The possibility of utilizing spin-dependent photoelectron diffraction to investigate magnetic ultrathin films will be demonstrated, using our preliminary spectra of the multiplet-split Fe3s os near-monolayer Fe/Cu(001). 18 refs., 10 figs.
Date: January 3, 1991
Creator: Tobin, J.G. (Lawrence Livermore National Lab., CA (USA)); Wagner, M.K. (Wisconsin Univ., Madison, WI (USA). Dept. of Chemistry); Guo, X.Q. & Tong, S.Y. (Wisconsin Univ., Milwaukee, WI (USA). Dept. of Physics)
Object Type: Article
System: The UNT Digital Library