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Implications of beam phase and RFSUM measured near transition
A technique using RF bucket reduction for acquiring information about the particle distribution in longitudinal phase space has been applied in the Fermilab Booster. Data sets were obtained at six important time intervals of a Booster cycle for three different beam intensities. Controlled RF bucket reduction also provides other opportunities for beam manipulation.
Date:
April 7, 2004
Creator:
Yang, Xi & MacLachlan, James
Object Type:
Report
System:
The UNT Digital Library
Production of e+e- Pairs Accompanied by Nuclear Dissociation in Ultra-peripheral Heavy Ion Collisions
We present the first data on e{sup +}e{sup -} pair production accompanied by nuclear breakup in ultra-peripheral gold-gold collisions at a center of mass energy of 200 GeV per nucleon pair. The nuclear breakup requirement selects events at small impact parameters, where higher-order corrections to the pair production cross section should be enhanced. We compare the pair kinematic distributions with two calculations: one based on the equivalent photon approximation, and the other using lowest-order quantum electrodynamics (QED); the latter includes the photon virtuality. The cross section, pair mass, rapidity and angular distributions are in good agreement with both calculations. The pair transverse momentum, p{sub T}, spectrum agrees with the QED calculation, but not with the equivalent photon approach. We set limits on higher-order contributions to the cross section. The e{sup +} and e{sup -} p{sub T} spectra are similar, with no evidence for interference effects due to higher-order diagrams.
Date:
April 7, 2004
Creator:
Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Allgower, C.; Amonett, J. et al.
Object Type:
Article
System:
The UNT Digital Library
Impedance studies of the thin film LiMn2O4/electrolyteinterface
Room-temperature impedance measurements of a thin-film LiMn2O4/LiPF6-EC-DMC interface have been used to identify the spontaneous formation Li2Mn2O4 at the interface at room temperature at voltages of 3.7 and higher. The impedance of the LiMn2O4 films exhibited two time constants: at about 14 kHz and 60 to 200 Hz. The high frequency loop is dependent on film morphology and was attributed to the substrate/oxide interface. The low frequency behavior was dependent on both state-of-charge (SOC) and time at a given SOC. At full charge the impedance in this electrolyte was stable at room temperature over several days. At high lithium contents, film OCV and impedance tended to grow logarithmically with time, with lower rates for lower Mn3+ content in the film. The increased impedance was removed by oxidation of the film to 4.5V vs. Li/Li+. The observations are consistent with a reversible disproportionation of part of the LiMn2O4 into Li2Mn2O4 and a lithium-deficient spinel. With extended constant current cycling part of the Li2Mn2O4 degrades to the Mn2O3 and the process is no longer reversible.
Date:
April 7, 2001
Creator:
Striebel, Kathryn A.; Sakai, E. & Cairns, Elton J.
Object Type:
Article
System:
The UNT Digital Library
Boron-Containing Compounds for Liposome-Mediated Tumor Localization and Application to Neutron Capture Therapy
Medical application of boron neutron capture therapy (BNCT) has been significantly hindered by the slow development of boron drug-targeting methodologies for the selective delivery of high boron concentration sto malignant cells. We have successfully sought to fill this need by creating liposomes suitable as in vivo boron delivery vehicles for BNCT. Delivery of therapeutic quantities of boron to tumors in murine models has been achieved with small unilamellar boron-rich liposomes. Subsequently, attempts have been made to improve delivery efficiency of liposomes encapsulating boron-containing water-soluble species into their hollow core by incorporating lipophilic boron compounds as addenda to the liposome bilayer, incorporating boron compounds as structural components of the bilayer (which however, poses the risk of sacrificing some stability), and combinations thereof. Regardless of the method, approximately 90% of the total liposome mass remains therapeutically inactive and comprised of the vehicle’s construction materials, while less than 5% is boron for neutron targeting. Following this laboratory's intensive study, the observed tumor specificity of certain liposomes has been attributed to their diminutive size of these liposomes (30-150 nm), which enables these small vesicles to pass through the porous, immature vasculature of rapidly growing tumor tissue. We surmised that any amphiphilic nanoparticle of suitable …
Date:
April 7, 2005
Creator:
Hawthorne, M. Frederick
Object Type:
Report
System:
The UNT Digital Library
A Theoretical Investigation of Mode-Locking Phenomena in Reversed Field Pinches
OAK-B135 This paper investigates the formation and breakup of the ''slinky mode'' in an RFP using analytic techniques previously employed to examine mode locking phenomena in tokamaks. The slinky mode is a toroidally localized, coherent interference pattern in the magnetic field which co-rotates with the plasma at the reversal surface. This mode forms, as a result of the nonlinear coupling of multiple m = 1 core tearing modes, via a bifurcation which is similar to that by which toroidally coupled tearing modes lock together in a tokamak. The slinky mode breaks up via a second bifurcation which is similar to that by which toroidally coupled tearing modes in a tokamak unlock. However, the typical m = 1 mode amplitude below which slinky breakup is triggered is much smaller than that above which slinky formation occurs. Analytic expressions for the slinky formation and breakup thresholds are obtained in all regimes of physical interest. The locking of the slinky mode to a static error-field is also investigated analytically. Either the error-field arrests the rotation of the plasma at the reversal surface before the formation of the slinky mode, so that the mode subsequently forms as a non-rotating mode, or the slinky mode …
Date:
April 7, 2004
Creator:
Fitzpatrick, Richard
Object Type:
Report
System:
The UNT Digital Library
Simulation of a Production Facility with an Automated Transport System
A model was needed to assess material throughput and validate the conceptual design of a production facility, including equipment lists and layout. The initial desire was to use a commercially available discrete event simulation package. However, the available software was found to be too limited in capability. Database interface software was used to develop autonomous intelligent manufacturing workstations and material transporters. The initial Extend model used to assess material throughput and develop equipment lists for the preconceptual design effort was upgraded with software add-ons from Simulation Dynamics, Inc. (SDI). Use of the SDI database interface allowed the upgraded model to include: 1. a material mass balance at any level of detail required by the user, and 2. a transport system model that includes all transport system movements, time delays, and transfers between systems. This model will assist in evaluating transport system capacity, sensitive time delays in the system, and optimal operating strategies. An additional benefit of using the SDI database interface is dramatically improved run time performance. This allows significantly more runs to be completed to provide better statistics for overall plant performance. The model has all system and process parameters entered into sub-component accessible tables. All information for the …
Date:
April 7, 2004
Creator:
ABRAMCZYK, GLENN
Object Type:
Report
System:
The UNT Digital Library
Simulating Electron Clouds in Heavy-Ion Accelerators
Contaminating clouds of electrons are a concern for most accelerators of positive-charged particles, but there are some unique aspects of heavy-ion accelerators for fusion and high-energy density physics which make modeling such clouds especially challenging. In particular, self-consistent electron and ion simulation is required, including a particle advance scheme which can follow electrons in regions where electrons are strongly-, weakly-, and un-magnetized. They describe their approach to such self-consistency, and in particular a scheme for interpolating between full-orbit (Boris) and drift-kinetic particle pushes that enables electron time steps long compared to the typical gyro period in the magnets. They present tests and applications: simulation of electron clouds produced by three different kinds of sources indicates the sensitivity of the cloud shape to the nature of the source; first-of-a-kind self-consistent simulation of electron-cloud experiments on the High-Current Experiment (HCX) at Lawrence Berkeley National Laboratory, in which the machine can be flooded with electrons released by impact of the ion beam and an end plate, demonstrate the ability to reproduce key features of the ion-beam phase space; and simulation of a two-stream instability of thin beams in a magnetic field demonstrates the ability of the large-timestep mover to accurately calculate the instability.
Date:
April 7, 2005
Creator:
Cohen, R. H.; Friedman, A.; Kireeff Covo, M.; Lund, S. M.; Molvik, A. W.; Bieniosek, F. M. et al.
Object Type:
Article
System:
The UNT Digital Library
Fundamental study on kinetics and transport phenomena in low water dilute acid total hydrolysis of cellulosic biomass
The overall objective of this research is to delineate the process of the dilute-acid hydrolysis of biomass and seek better understanding of the reactions involving dilute-acid treatment of lignocellulosic biomass. Specifically the scope of the work entails the following two primary technical elements: Verification of the heterogeneous nature of the reaction mechanism in dilute-acid hydrolysis of cellulosic component of the biomass. Experimental investigation to identify the overall reaction pattern and the kinetic constants associated with dilute-acid hydrolysis of the cellulosic component of the agricultural residues.
Date:
April 7, 2004
Creator:
Auburn University
Object Type:
Report
System:
The UNT Digital Library
Characterization of liquid phase epitaxial GaAs forblocked-impurity-band far-infrared detectors
GaAs Blocked-Impurity-Band (BIB) photoconductor detectors have the potential to become the most sensitive, low noise detectors in the far-infrared below 45.5 cm{sup -1} (220 {micro}m). We have studied the characteristics of liquid phase epitaxial GaAs films relevant to BIB production, including impurity band formation and the infrared absorption of the active section of the device. Knowledge of the far-infrared absorption spectrum as a function of donor concentration combined with variable temperature Hall effect and resistivity studies leads us to conclude that the optimal concentration for the absorbing layer of a GaAs BIB detector lies between 1 x 10{sup 15} and 6.7 x 10{sup 15} cm{sup -3}. At these concentrations there is significant wavefunction overlap which in turn leads to absorption beyond the 1s ground to 2p bound excited state transition of 35.5 cm{sup -1} (282 {micro}m). There still remains a gap between the upper edge of the donor band and the bottom of the conduction band, a necessity for proper BIB detector operation.
Date:
April 7, 2004
Creator:
Cardozo, B. L.; Reichertz, L. A.; Beeman, J. W. & Haller, E. E.
Object Type:
Article
System:
The UNT Digital Library
CANISTER HANDLING FACILITY CRITICALITY SAFETY CALCULATIONS
This design calculation revises and updates the previous criticality evaluation for the canister handling, transfer and staging operations to be performed in the Canister Handling Facility (CHF) documented in BSC [Bechtel SAIC Company] 2004 [DIRS 167614]. The purpose of the calculation is to demonstrate that the handling operations of canisters performed in the CHF meet the nuclear criticality safety design criteria specified in the ''Project Design Criteria (PDC) Document'' (BSC 2004 [DIRS 171599], Section 4.9.2.2), the nuclear facility safety requirement in ''Project Requirements Document'' (Canori and Leitner 2003 [DIRS 166275], p. 4-206), the functional/operational nuclear safety requirement in the ''Project Functional and Operational Requirements'' document (Curry 2004 [DIRS 170557], p. 75), and the functional nuclear criticality safety requirements described in the ''Canister Handling Facility Description Document'' (BSC 2004 [DIRS 168992], Sections 3.1.1.3.4.13 and 3.2.3). Specific scope of work contained in this activity consists of updating the Category 1 and 2 event sequence evaluations as identified in the ''Categorization of Event Sequences for License Application'' (BSC 2004 [DIRS 167268], Section 7). The CHF is limited in throughput capacity to handling sealed U.S. Department of Energy (DOE) spent nuclear fuel (SNF) and high-level radioactive waste (HLW) canisters, defense high-level radioactive waste (DHLW), …
Date:
April 7, 2005
Creator:
Sanders, C.E.
Object Type:
Report
System:
The UNT Digital Library
Center for Catalysis
None
Date:
April 7, 2005
Creator:
Kraus, George A.
Object Type:
Report
System:
The UNT Digital Library
DIRECT ENERGY CONVERSION FISSION REACTOR ANNUAL REPORT FOR THE PERIOD OCTOBER 1, 2001 THROUGH DECEMBER 31, 2002
OAK-B135 DIRECT ENERGY CONVERSION FISSION REACTOR ANNUAL REPORT FOR THE PERIOD OCTOBER 1, 2001 THROUGH DECEMBER 31, 2002
Date:
April 7, 2003
Creator:
BROWN, L.C.
Object Type:
Report
System:
The UNT Digital Library
Potential VOC Deflagrations in a Vented TRU Drum
The objective of the analysis is to examine the potential for lid ejection from a vented transuranic (TRU) waste drum due to pressure buildup caused by the deflagration of hydrogen and volatile organic compounds (VOCs) inside the drum. In this analysis, the AICC pressure for a stoichiometric mixture of VOCs is calculated and then compared against the experimental peak pressure of stoichiometric combustion of propane and hexane in a combustion chamber. The experimental peak pressures of propane and hexane are about 12 percent lower than the calculated AICC pressure. Additional losses in the drum are calculated due to venting of the gases, drum bulging, waste compaction, and heat losses from the presence of waste in the drum. After accounting for these losses, the final pressures are compared to the minimum observed pressure that ejects the lid from a TRU drum. The ejection pressure of 105 psig is derived from data that was recorded for a series of tests where hydrogen-air mixtures were ignited inside sealed TRU drums. Since the calculated pressures are below the minimum lid ejection pressure, none of the VOCs and the hydrogen (up to 4 percent) mixtures present in the TRU waste drum is expected to cause …
Date:
April 7, 2005
Creator:
Mukesh, GUPTA
Object Type:
Article
System:
The UNT Digital Library
Particle Tracking Model and Abstraction of Transport Processes
The purpose of the transport methodology and component analysis is to provide the numerical methods for simulating radionuclide transport and model setup for transport in the unsaturated zone (UZ) site-scale model. The particle-tracking method of simulating radionuclide transport is incorporated into the FEHM computer code and the resulting changes in the FEHM code are to be submitted to the software configuration management system. This Analysis and Model Report (AMR) outlines the assumptions, design, and testing of a model for calculating radionuclide transport in the unsaturated zone at Yucca Mountain. In addition, methods for determining colloid-facilitated transport parameters are outlined for use in the Total System Performance Assessment (TSPA) analyses. Concurrently, process-level flow model calculations are being carrier out in a PMR for the unsaturated zone. The computer code TOUGH2 is being used to generate three-dimensional, dual-permeability flow fields, that are supplied to the Performance Assessment group for subsequent transport simulations. These flow fields are converted to input files compatible with the FEHM code, which for this application simulates radionuclide transport using the particle-tracking algorithm outlined in this AMR. Therefore, this AMR establishes the numerical method and demonstrates the use of the model, but the specific breakthrough curves presented do not …
Date:
April 7, 2000
Creator:
Robinson, B.
Object Type:
Report
System:
The UNT Digital Library
Top physics: measurement of the tt-bar production cross section in p anti-p collisions at s**(1/2) = 1.96 tev using lepton + jets events with secondary vertex b-tagging
We present a measurement of the t{bar t} production cross section using events with one charged lepton and jets from p{bar p} collisions at a center-of-mass energy of 1.96TeV. In these events, heavy flavor quarks from top quark decay are identified with a secondary vertex tagging algorithm. From 162 pb{sup -1} of data collected by the Collider Detector at Fermilab, a total of 48 candidate events are selected, where 13.5 {+-} 1.8 events are expected from background contributions. We measure a t{bar t} production cross section of 5.6{sub -1.1}{sup _1.2}(stat.){sub -0.6}{sup +0.9}(syst.)pb.
Date:
April 7, 2005
Creator:
Acosta, D.
Object Type:
Report
System:
The UNT Digital Library
Natural and Passive Remediation of Chlorinated Solvents: Critical Evaluation of Science and Technology Targets
This report was written for multiple audiences. Each reader will likely approach the subject from a different perspective, seeking different information. The team that developed the document consisted of several technical experts on monitored natural attenuation (MNA) and included participants who were integral in the development of US EPA's chlorinated solvent MNA protocol and the subsequent US EPA and Office of Solid Waste and emergency Response (OSWER) policy directive. The primary assignment to the interdisciplinary team was to generate a summary of the state-of-the-art, particularly for chlorinated solvent applications and to identify high-priority opportunities for advancement. A diverse jury of peers reviewed the draft report; the report was edited in response to their comments.
Date:
April 7, 2004
Creator:
Looney, Brian
Object Type:
Report
System:
The UNT Digital Library
300 Area Liquid Effluent Facilities (LEF) Authorization Envelope
The purpose of this document is to establish the facility Authorization Envelope (AE) for the 300 Liquid Effluent Facilities (LEP )Project and identify the requirements related to the maintenance of the AE as Specified in HNF-PRO-2701, Authorization Envelope and Authorization Agreement. The 300 LEF Project consists of two separate facilities operating under one management organization. They are the 310 Facility and the 340 Facility. The AE documents the limits of operations for all 300 LEF Project activities.
Date:
April 7, 2000
Creator:
WRIGHT, E.J. & STORDEUR, R.T.
Object Type:
Report
System:
The UNT Digital Library
Risk-Based Management of Contaminated Groundwater: The Role of Geologic Heterogeneity, Exposure and Cancer Risk in Determining the Performance of Aquifer Remediation
The effectiveness of aquifer remediation is typically expressed in terms of a reduction in contaminant concentrations relative to a regulated maximum contaminant level (MCL), and is usually confined by sparse monitoring data and/or simple model calculations. Here, the effectiveness of remediation is examined from a risk-based perspective that goes beyond the traditional MCL concept. A methodology is employed to evaluate the health risk to individuals exposed to contaminated household water that is produced from groundwater. This approach explicitly accounts for differences in risk arising from variability in individual physiology and water use, the uncertainty in estimating chemical carcinogenesis for different individuals, and the uncertainties and variability in contaminant concentrations within groundwater. A hypothetical contamination scenario is developed as a case study in a saturated, alluvial aquifer underlying a real Superfund site. A baseline (unremediated) human exposure and health risk scenario, as induced by contaminated groundwater pumped from this site, is predicted and compared with a similar estimate based upon pump-and-treat exposure intervention. The predicted reduction in risk in the remediation scenario is not an equitable one--that is, it is not uniform to all individuals within a population and varies according to the level of uncertainty in prediction. The importance of …
Date:
April 7, 2000
Creator:
Maxwell, R. M.; Carle, S. F. & Tompson, A. F. B.
Object Type:
Article
System:
The UNT Digital Library
QA Verification of Computer Codes Used in ORNL/TM-1999/159
This report describes QA verification exercises carried out for the computer codes applied in the analyses summarized ''Stress Intensity Factors for HFIR HB-2 Nozzle Corner'' (ORNL/TM-1999/159). Several benchmark problems are presented that establish the following: (1) The version of the finite-element mesh generator code ORNOZL used in the subject analyses reproduces the results of the two sample problems given in its previously published user's guide. (2) The ABAQUS code reproduces, independently of ORNOZL, the results of a benchmark verification problem given in its Example Problems Manual that compares linear-elastic stress intensity factors for semi-elliptical surface flaws to solutions published in the literature. (3) The ORNOZL/ABAQUS code combination was benchmarked against an approximate method for estimating linear-elastic stress-intensity factors for corner flaws in pressure vessel nozzles. In addition, all input and output files produced during the analyses described in ORNL/TM-1999/159 have been archived on an electronic medium (CD-R74-ORNL/TM-1999/159) and transmitted with this report to ORNL Research Reactors Division personnel for archival storage.
Date:
April 7, 2000
Creator:
Williams, P.T.
Object Type:
Report
System:
The UNT Digital Library
The global unified parallel file system (GUPFS) project: FY 2002 activities and results
The Global Unified Parallel File System (GUPFS) project is a multiple-phase, five-year project at the National Energy Research Scientific Computing (NERSC) Center to provide a scalable, high performance, high bandwidth, shared file system for all the NERSC production computing and support systems. The primary purpose of the GUPFS project is to make it easier to conduct advanced scientific research using the NERSC systems. This is to be accomplished through the use of a shared file system providing a unified file namespace, operating on consolidated shared storage that is directly accessed by all the NERSC production computing and support systems. During its first year, FY 2002, the GUPFS project focused on identifying, testing, and evaluating existing and emerging shared/cluster file system, SAN fabric, and storage technologies; identifying NERSC user input/output (I/O) requirements, methods, and mechanisms; and developing appropriate benchmarking methodologies and benchmark codes for a parallel environment. This report presents the activities and progress of the GUPFS project during its first year, the results of the evaluations conducted, and plans for near-term and longer-term investigations.
Date:
April 7, 2003
Creator:
Butler, Gregory F.; Lee, Rei Chi & Welcome, Michael L.
Object Type:
Report
System:
The UNT Digital Library
Texas Register, Volume 25, Number 14, Pages 2869-3110, April 07, 2000
A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date:
April 7, 2000
Creator:
Texas. Secretary of State.
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History
[News Clip: Area Codes]
Video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
April 7, 2000, 6:00 p.m.
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
Enemy Combatant Detainees: Habeas Corpus Challenges in Federal Court
This report provides an overview of the early judicial developments and the establishment of Combatant Status Review Tribunals (CSRTs) procedures; summarizes selected court cases related to the detentions and the use of military commissions; and discusses the Detainee Treatment Act, as amended by the Military Commissions Act of 2006 and the Military Commissions Act of 2009, analyzing its effects on detainee-related litigation in federal court. The report summarizes the Supreme Court's decision in Boumediene invalidating Congress's efforts to revoke the courts' habeas jurisdiction, and discusses some remaining issues and subsequent developments.
Date:
April 7, 2009
Creator:
Elsea, Jennifer K. & Garcia, Michael J.
Object Type:
Report
System:
The UNT Digital Library
Information Security: Continued Efforts Needed to Sustain Progress in Implementing Statutory Requirements
Testimony issued by the Government Accountability Office with an abstract that begins "For many years, GAO has reported that poor information security is a widespread problem that has potentially devastating consequences. Further, since 1997, GAO has identified information security as a governmentwide high-risk issue in reports to Congress--most recently in January 2005. Concerned with accounts of attacks on commercial systems via the Internet and reports of significant weaknesses in federal computer systems that make them vulnerable to attack, Congress passed the Federal Information Security Management Act of 2002 (FISMA), which permanently authorized and strengthened the federal information security program, evaluation, and reporting requirements established for federal agencies. This testimony discusses the federal government's progress and challenges in implementing FISMA as reported by the Office of Management and Budget (OMB), the agencies, and Inspectors General (IGs) and opportunities for improving the usefulness of the annual reporting process, including the consideration of a common framework for the annual FISMA reviews conducted by the IGs."
Date:
April 7, 2005
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library