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Rate coefficients and mechanistic analysis for the reaction of hydroxyl radicals with 1,1-dichloroethylene and trans-1,2-dichloroethylene over an extended temperature range

Description: Article on rate coefficients and mechanistic analysis for the reaction of hydroxyl radicals with 1,1-dichloroethylene and trans-1,2-dichloroethylene over an extended temperature range.
Date: July 17, 2001
Creator: Yamada, Takahiro; El-Sinawi, Abdulaziz; Siraj, Mohammad Masud, 1972-; Taylor, Philip H.; Peng, Jingping; Hu, Xiaohua et al.
Partner: UNT College of Arts and Sciences

Care and Health

Description: Encyclopedia article in the 'International Encyclopedia of Economic Sociology' discussing health care, globalization and health, and the effect of the economy on the structure of the health care system.
Date: December 17, 2005
Creator: Eve, Susan Brown
Partner: UNT College of Public Affairs and Community Service

Microstructure of GaN Grown on (111) Si by MOCVD

Description: Gallium nitride was grown on (111) Si by MOCVD by depositing an AIN buffer at 108O"C and then GaN at 1060 {degrees}C. The 2.2pm layer cracked along {1-100} planes upon cooling to room temperature, but remained adherent. We were able to examine the microstructure of material between cracks with TEM. The character and arrangement of dislocation are much like those of GaN grown on Al{sub 2}O{sub 3}: -2/3 pure edge and - 1/3 mixed (edge + screw), arranged in boundaries around domains of GaN that are slightly disoriented with respect to neighboring material. The 30 nm AIN buffer is continuous, indicating that AIN wets the Si, in contrast to GaN on Al{sub 2}O{sub 3}.
Date: December 17, 1998
Creator: Fleming, J.G.; Follstaedt, D.M.; Han, J. & Provencio, P.
Partner: UNT Libraries Government Documents Department

Self-consistent core-edge nonlinear transport simulations with CORSICA 2

Description: The coupled core-edge nonlinear transport code CORSICA 2 is introduced and the structure of its iterative coupling algorithm is briefly discussed. Selected application results are reported that reproduce equilibria in DIII-D discharges with plasma profiles initialized from the experimental data. Simulations for an L-H transition and for a gas puffing experiment in DIII-D plasmas are presented.
Date: January 17, 1996
Creator: Tarditi, A.; Cohen, R.H. & Craddock, G.G.
Partner: UNT Libraries Government Documents Department

Reliable software systems via chains of object models with provably correct behavior

Description: This work addresses specification and design of reliable safety-critical systems, such as nuclear reactor control systems. Reliability concerns are addressed in complimentary fashion by different fields. Reliability engineers build software reliability models, etc. Safety engineers focus on prevention of potential harmful effects of systems on environment. Software/hardware correctness engineers focus on production of reliable systems on the basis of mathematical proofs. The authors think that correctness may be a crucial guiding issue in the development of reliable safety-critical systems. However, purely formal approaches are not adequate for the task, because they neglect the connection with the informal customer requirements. They alleviate that as follows. First, on the basis of the requirements, they build a model of the system interactions with the environment, where the system is viewed as a black box. They will provide foundations for automated tools which will (a) demonstrate to the customer that all of the scenarios of system behavior are presented in the model, (b) uncover scenarios not present in the requirements, and (c) uncover inconsistent scenarios. The developers will work with the customer until the black box model will not possess scenarios (b) and (c) above. Second, the authors will build a chain of several increasingly detailed models, where the first model is the black box model and the last model serves to automatically generated proved executable code. The behavior of each model will be proved to conform to the behavior of the previous one. They build each model as a cluster of interactive concurrent objects, thus they allow both top-down and bottom-up development.
Date: May 17, 1996
Creator: Yakhnis, A. & Yakhnis, V.
Partner: UNT Libraries Government Documents Department

Modeling of filamentation damage induced in silica by 351-nm laser pulses

Description: A major risk factor that must be considered in design of the National Ignition Facility is the possibility for catastrophic self-focusing of the 351-nm beam in the silica optical components that are in the final section of the laser. Proposed designs for the laser are analyzed by the beam-propagation code PROP92. A 351-nm self-focusing experiment, induction of tracking damage, was done to provide data for validation of this code. The measured self-focusing lengths were correctly predicted by the code.
Date: October 17, 1996
Creator: Milam, D.; Manes, K.R. & Williams, W.H.
Partner: UNT Libraries Government Documents Department

Initial experience with the CDF layer 00 silicon detector

Description: We report on initial experience with the CDF Layer 00 Detector. Layer 00 is an innovative, low-mass, silicon detector installed in CDF during the upgrade for Run 2A of the Tevatron. Noise pickup present during operation at CDF is discussed. An event-by-event pedestal correction implemented by CDF is presented. This off-line solution prevents L00 from being used in the current incarnation of the on-line displaced track trigger. Preliminary performance of Layer 00 is described.
Date: March 17, 2003
Creator: Hill, C.
Partner: UNT Libraries Government Documents Department

High pT inclusive charged hadron spectra from Au+Au collisions at {radical}(s{sub NN}) = 200 Gev

Description: The STAR Collaboration presents new measurements of inclusive charged hadron distributions for p{sub T} < 12 GeV/c from Au+Au collisions at {radical}(s{sub NN}) = 200GeV. Charged hadron suppression at high p{sub T} is similar in shape and magnitude at all centralities to that observed previously at {radical}(s{sub NN}) = 130 GeV for p{sub T} < 6 GeV/c. The ratio of spectra from central and peripheral Au+Au collisions shows that hadron suppression is approximately constant within 6 < p{sub T} < 12 GeV/c. The ratios of charged hadron spectra at the two beam energies show a 15-20 percent increase in yield at low p{sub T}. At high p{sub T}, the ratios show a larger increase that agrees well with pQCD calculations of the {radical}(s{sub NN}) dependence of particle production in Au+Au collisions.
Date: October 17, 2002
Creator: Klay, Jennifer L. & Collaboration, STAR
Partner: UNT Libraries Government Documents Department

Melt-Dilute Form of Al-Based Spent Nuclear Fuel Disposal Criticality Summary Report

Description: Criticality analysis of the proposed melt-dilute (MD) form of aluminum-based spent nuclear fuel (SNF), under geologic repository conditions, was performed following the methodology documented in the Disposal Criticality Analysis Methodology Topical Report. This methodology evaluates the potential for nuclear criticality for a waste form in a waste package. Criticality calculations show that even with waste package failure, followed by degradation of material within the waste package and potential loss of neutron absorber materials, sub-critical conditions can be readily demonstrated for the MD form of aluminum-based SNF.
Date: September 17, 2002
Creator: Vinson, D.W.
Partner: UNT Libraries Government Documents Department

Development of a California commercial building benchmarking database

Description: Building energy benchmarking is a useful starting point for commercial building owners and operators to target energy savings opportunities. There are a number of tools and methods for benchmarking energy use. Benchmarking based on regional data can provides more relevant information for California buildings than national tools such as Energy Star. This paper discusses issues related to benchmarking commercial building energy use and the development of Cal-Arch, a building energy benchmarking database for California. Currently Cal-Arch uses existing survey data from California's Commercial End Use Survey (CEUS), a largely underutilized wealth of information collected by California's major utilities. Doe's Commercial Building Energy Consumption Survey (CBECS) is used by a similar tool, Arch, and by a number of other benchmarking tools. Future versions of Arch/Cal-Arch will utilize additional data sources including modeled data and individual buildings to expand the database.
Date: May 17, 2002
Creator: Kinney, Satkartar & Piette, Mary Ann
Partner: UNT Libraries Government Documents Department

From design through operations-Results from new construction performance contract and beyond

Description: As part of the High Performance Commercial Building Systems program, LBNL has been working with the City of Oakland to understand the ongoing performance of the Oakland Administration Buildings. The primary objective of this research is to understand the performance targets and ongoing performance of two buildings that were the subject of a new construction performance contract. Secondary objectives include examining the building performance information systems developed as part of the new construction performance contract and evaluating the role of the energy management and control system (EMCS) as a data acquisition tool to provide recommendations for future new construction projects. We examine the results of the performance contract in detail, and provide additional performance metrics that go beyond what was required in the performance contract. We found that the energy cost intensities (ECI) linked to the project ranged from $1.08/ft{sup 2} to $1.44/ft{sup 2}. Changes in floor area, energy costs, rate schedules, and energy use complicate the evaluation of the performance because of the lack of tracking of underlying data and assumptions. Overall, Oakland has two large office buildings with relatively low-energy use (50 kBtu/ft{sup 2}-yr site electricity and gas use). We compare this energy-use intensity with a number of related benchmarks. Additional end-use, HVAC performance, and diagnostics data are discussed.
Date: May 17, 2002
Creator: Motegi, Naoya; Piette, Mary Ann & Wentworth, Scott
Partner: UNT Libraries Government Documents Department

Microbial Forensics: A Scientific Assessment

Description: Microorganisms have been used as weapons in criminal acts, most recently highlighted by the terrorist attack using anthrax in the fall of 2001. Although such ''biocrimes'' are few compared with other crimes, these acts raise questions about the ability to provide forensic evidence for criminal prosecution that can be used to identify the source of the microorganisms used as a weapon and, more importantly, the perpetrator of the crime. Microbiologists traditionally investigate the sources of microorganisms in epidemiological investigations, but rarely have been asked to assist in criminal investigations. A colloquium was convened by the American Academy of Microbiology in Burlington, Vermont, on June 7-9, 2002, in which 25 interdisciplinary, expert scientists representing evolutionary microbiology, ecology, genomics, genetics, bioinformatics, forensics, chemistry, and clinical microbiology, deliberated on issues in microbial forensics. The colloquium's purpose was to consider issues relating to microbial forensics, which included a detailed identification of a microorganism used in a bioattack and analysis of such a microorganism and related materials to identify its forensically meaningful source--the perpetrators of the bioattack. The colloquium examined the application of microbial forensics to assist in resolving biocrimes with a focus on what research and education are needed to facilitate the use of microbial forensics in criminal investigations and the subsequent prosecution of biocrimes, including acts of bioterrorism. First responders must consider forensic issues, such as proper collection of samples to allow for optimal laboratory testing, along with maintaining a chain of custody that will support eventual prosecution. Because a biocrime may not be immediately apparent, a linkage must be made between routine diagnosis, epidemiological investigation, and criminal investigation. There is a need for establishing standard operating procedures and training to meet these initial challenges so as minimize disturbance of the evidence. While epidemiology and forensics are similar sciences with similar goals when ...
Date: February 17, 2003
Creator: Keim, Paul
Partner: UNT Libraries Government Documents Department

Challenges of Non-Destructive Assay Waste Measurement

Description: Historically, the Savannah River Site (SRS) routinely produced special nuclear material (SNM), which provided stable measurement conditions for the non-destructive assay (NDA) methods. However, the main mission of SRS has changed from the production of SNM to the processing of waste and material stabilization. Currently, the purpose of processing is to recover the SNM from the waste and stabilization materials, much of which is from other DOE facilities. These missions are usually of a short duration, but require non-destructive assay (NDA) accountability measurements on materials of varying composition and geometric configuration. These missions usually have cost and time constraints, which sometimes require re-application of existing NDA methods to waste measurements. Usually, each new material or re-application of the NDA method to a different SNM campaign requires new standards and timely re-calibration of the method. These constraints provide numerous challenges for the NDA methods, particularly in the area of measurement uncertainty. This paper will discuss the challenges of these situations, mainly from a measurement and statistical point of view and provide some possible solutions to the problems encountered. Specific examples will be discussed for the segmented gamma scanner (SGS), neutron multiplicity counter (NMC) and passive neutron coincidence counter (PNCC), which are some of the most common NDA instruments at SRS.
Date: June 17, 2003
Creator: Shull, A.H.
Partner: UNT Libraries Government Documents Department

Recent Run II Electroweak and QCD Results from D0

Description: The D0 Detector is a hermetic, multipurpose detector residing at one interaction region designated for p{bar p} collisions at 2 TeV at the Fermilab Tevatron. Both the detector and accelerator have undergone major upgrades to increase the luminosity and handle higher interaction rates. This paper presents recent results from Run II data which explore QCD and electroweak physics at the energy frontier. The dijet mass cross section and a search for Z' in dielectron decays are presented, and these are already approaching sensitivities seen in Run I. Additionally, the first measurement of the {sigma}{sub Z} * BR(Z {yields} {mu}{mu}) is given for the new collision energy.
Date: December 17, 2003
Creator: Kehoe, Robert L.
Partner: UNT Libraries Government Documents Department

Low amplitude impact testing and analysis of pristine and aged solid high explosives

Description: The critical impact velocities of 60.1 mm diameter blunt steel projectiles required for ignition of exothermic chemical reaction were determined for heavily confined charges of new and aged (15-30 years) solid HMX-based high explosives. The explosives in order of decreasing impact sensitivity were: PBX 9404; LX-lo; LX-14; PBX 9501; and LX-04. Embedded pressure gauges measured the interior pressure histories. Stockpile aged LX-04 and PBX 9501 from dismantled units were tested and compared to freshly pressed charges. The understanding of explosive aging on impact ignition and other hazards must improve as systems are being deployed longer than their initial estimated lifetimes. The charges that did not react on the first impact were subjected to multiple impacts. While the violence of reaction increased with impact velocity, it remained much lower than that produced by an intentional detonation. Ignition and Growth reactive flow models were developed to predict HMX-based explosive impact sensitivity in other geometries and scenarios.
Date: August 17, 1998
Creator: Chidester, S K; Garza, R & Tarver, C M
Partner: UNT Libraries Government Documents Department

Investigation of the persistence of new building commissioning

Description: Commissioning is gaining increasing recognition as a cost-effective strategy for reducing commercial building energy use. Although the success and cost-effectiveness of commissioning projects depends on how well the benefits of commissioning persist over time, this aspect of commissioning is not well understood. The persistence of commissioning benefits was recently studied in a PIER project evaluating ten buildings that were commissioned at building start-up at least two years ago. The researchers examined the commissioning reports, control algorithms, EMCS point measurements, and energy use data, and conducted operator and commissioning provider interviews to investigate the persistence of commissioning benefits. In addition, they conducted site visits in a sample of the buildings. A set of commissioning measures was selected for each building to compare the persistence of benefits. Persistence was measured both qualitatively through a discussion of occupant comfort and decreased maintenance and quantitatively through estimations of energy savings. This paper reports the results of the study. The discussion includes how well the benefits of commissioning persisted over time, reasons for declining performance, and methods for improving persistence. The results provide valuable insight into how to estimate the persistence of commissioning information central to the cost benefit analyses routinely performed for commissioning measures.
Date: March 17, 2002
Creator: Potter, Amanda; Friedman, Hannah; Haasl, Tudi & Claridge, David
Partner: UNT Libraries Government Documents Department

Run II diffractive measurements at CDF

Description: We present results on hard diffraction obtained by the CDF Collaboration in Run II proton-antiproton collisions at the Fermilab Tevatron. Run I CDF results on hard diffraction are also reviewed.
Date: September 17, 2003
Creator: Terashi, K.
Partner: UNT Libraries Government Documents Department

Diagnostic and numerical studies of the IPNS LINAC with a recently installed buncher amplifier.

Description: The Intense Pulse Neutron Source (IPNS) 50-MeV Drift-Tube Linac uses a single-gap, single-harmonic buncher cavity to increase transmission efficiency. However, it is also the case that the linac output beam longitudinal and transverse emittance is dependent on buncher amplitude and phase as well as with the input beam energy and emittance. The linac is the injector for a Rapid Cycling Synchrotron (RCS) that increases the beam energy to 450 MeV and shortens the pulse to the 100 ns region. The RCS is operated loss-limited, and its operating current is strongly dependent on the properties (emittance, and its variation during the pulse) of the beam from the linac. A new amplifier has been installed allowing for better amplitude and phase control of buncher rf. This new amplifier gives independent control of amplitude and phase, permitting more systematic studies of the relation between linac and RCS performance. This paper presents the results of recent studies where we characterize beam properties that lead to high efficiency operation in both linac and RCS, and compare them with simulation calculations.
Date: September 17, 2002
Creator: Dooling, J. C.; Donley, L. I.; McMichael, G. E. & Stipp, V. F.
Partner: UNT Libraries Government Documents Department

Simulations of Underground Structures Subjected to Synamic Loading Using the Distinct Element Method

Description: The authors present results from a parameter study investigating the stability of underground structures in response to ground shock. Direct simulation requires detailed knowledge of both the facility itself and the surrounding geology. In practice, however, key details (joint spacing, joint stiffness, reinforcement) may not be available. Thus, in order to place bounds upon the predicted behavior of a given facility, an extensive series of simulations representing different realizations may be required. They will discuss the distinct element method (DEM) with particular emphasis on techniques for achieving improved computational efficiency, including the handling of contact detection and approaches to parallelization. Some continuum approaches to the simulation of underground facilities are discussed along with results from underground explosions. Finally, their DEM code is used to simulate dynamic loading of several generic subterranean facilities in hard rock for a range of joint properties and sources, demonstrating the suitability of the DEM for this application.
Date: April 17, 2002
Creator: Morris, J.P.; Glenn, L.A.; Heuze, F.E. & Blair, S.C.
Partner: UNT Libraries Government Documents Department

A Model for Short Gamma-Ray Bursts: Heated Neutron Stars in Close Binary Systems

Description: In this paper we present a model for the short (< second) population of gamma-ray bursts (GRBs). In this model heated neutron stars in a close binary system near their last stable orbit emit neutrinos at large luminosities ({approx} 10{sup 53} ergs/sec). A fraction of these neutrinos will annihilate to form an e{sup +}e{sup -} pair plasma wind which will, in turn, expand and recombine to photons which make the gamma-ray burst. We study neutrino annihilation and show that a substantial fraction ({approx}1/2) of energy deposited comes from inter-star neutrinos, where each member of the neutrino pair originates from each neutron star. Thus, in addition to the annihilation of neutrinos blowing off of a single star, we have a new source of baryon free energy that is deposited between the stars. To model the e{sup +}e{sup -} pair plasma wind between stars, we do three-dimensional relativistic numerical hydrodynamic calculations. Preliminary results are also presented of new, fully general relativistic calculations of gravitationally attracting stars falling from infinity with no angular momentum. These simulations exhibit a compression effect.
Date: December 17, 2001
Creator: Salmonson, J.D. & Wilson, J.R.
Partner: UNT Libraries Government Documents Department

Determination of unsaturated flow paths in a randomly distributed fracture network

Description: We present a numerical investigation of steady flow paths in a two-dimensional, unsaturated discrete-fracture network. The fracture network is constructed using field measurement data including fracture density, trace lengths, and orientations from a particular site. The fracture network with a size of 100m x 150m contains more than 20,000 fractures. The steady state unsaturated flow in the fracture network is investigated for different boundary conditions. Simulation results indicate that the flow paths are generally vertical, and horizontal fractures mainly provide pathways between neighboring vertical paths. The simulation results support that the average spacing between flow paths in a layered system tends to increase or flow becomes more focused with depth as long as flow is gravity driven (Liu et al. 2002).
Date: February 17, 2003
Creator: Zhang, Keni; Wu, Yu-Shu; Bodvarsson, G.S. & Liu, Hui-Hai
Partner: UNT Libraries Government Documents Department