Beam-Cavity Interaction Circuit at W-Band (open access)

Beam-Cavity Interaction Circuit at W-Band

We describe the design, fabrication and bench-study of a mm-wave cavity employed as a relativistic klystron output structure. The OFE copper cavity was prepared by electro-discharge machining and diffusion bonding, cleaned, and tuned to 91.4 GHz. Measured cavity characteristics are presented and compared with theory, including quality factor, Q, coupling parameter {beta}, scattering matrix S{sub 11}, and axial electric field profile E{sub z}. This work provides the basis for understanding of the cavity as a transfer structure.
Date: July 14, 1999
Creator: Hill, Marc E
Object Type: Report
System: The UNT Digital Library
Beam Profile Measurement at 30 GeV Using Optical Transition Radiation (open access)

Beam Profile Measurement at 30 GeV Using Optical Transition Radiation

We present results of measurements of spot size and angular divergence of a 30 GeV electron beam through use of optical transition radiation (OTR). The OTR near field pattern and far field distribution are measured as a function of beam spot size and divergence at wavelengths of 441, 532, and 800 nm, for both the single and double foil configurations. Electron beam spot sizes of 50 {micro}m rms have been resolved, demonstrating the utility of OTR for measurement of small beam spot sizes of high energy (30 GeV) electron beams. Two-foil interference was clearly observed and utilized electron beam angular divergences of {approximately} 100 {micro}rad.
Date: July 10, 1999
Creator: Whittum, David H
Object Type: Report
System: The UNT Digital Library
Behavior model for performance assessment. (open access)

Behavior model for performance assessment.

Every individual channels information differently based on their preference of the sensory modality or representational system (visual auditory or kinesthetic) we tend to favor most (our primary representational system (PRS)). Therefore, some of us access and store our information primarily visually first, some auditorily, and others kinesthetically (through feel and touch); which in turn establishes our information processing patterns and strategies and external to internal (and subsequently vice versa) experiential language representation. Because of the different ways we channel our information, each of us will respond differently to a task--the way we gather and process the external information (input), our response time (process), and the outcome (behavior). Traditional human models of decision making and response time focus on perception, cognitive and motor systems stimulated and influenced by the three sensory modalities, visual, auditory and kinesthetic. For us, these are the building blocks to knowing how someone is thinking. Being aware of what is taking place and how to ask questions is essential in assessing performance toward reducing human errors. Existing models give predications based on time values or response times for a particular event, and may be summed and averaged for a generalization of behavior(s). However, by our not establishing …
Date: July 23, 1999
Creator: Borwn-VanHoozer, S. A.
Object Type: Article
System: The UNT Digital Library
Behavior of excess electrons in supercritical fluids -- Electron attachment (open access)

Behavior of excess electrons in supercritical fluids -- Electron attachment

The behavior of excess electrons in supercritical ethane was investigated by measuring mobility and reaction rates. Mobilities wee measured by means of a time-of-flight method at 306--320 K as a function of pressure. Mobility values decreased at all temperatures with increasing pressure, but showed a small minimum or a shoulder at the pressure where the compressibility {chi}{sub T} has a peak. Electron attachment to CO{sub 2}, NO, pyrimidine and C{sub 2}F{sub 4} over the same temperature range was studied as a function of pressure. Both attachment rate constants k{sub a} for NO and C{sub 2}F{sub 4}, and equilibrium constants K({double_bond}k{sub a}/k{sub d}) for CO{sub 2} and pyrimidine increased sharply at pressures of {chi}{sub T} peaks. Activation volumes V{sub a}* and reaction volumes {Delta}V{sub r} are very large and negative in the critical region. The volume change is mainly due to electrostriction around ions formed. The results are compared to volume changes predicted by a compressible continuum model.
Date: July 1, 1999
Creator: Nishikawa, Masaru; Holroyd, R.A. & Itoh, Kengo
Object Type: Report
System: The UNT Digital Library
Behavior of Excess Electrons in Supercritical Fluids - Electron Attachment (open access)

Behavior of Excess Electrons in Supercritical Fluids - Electron Attachment

The behavior of excess electrons in supercritical ethane was investigated by measuring mobility and reaction rates. Mobilities were measured by means of a time-of-flight method at 306--320K as a function of pressure. Mobility values decreased at all temperatures with increasing pressure, but showed a small minimum or a shoulder at the pressure where the compressibility {chi}{sub T} has a peak. Electron attachment to CO{sub 2}, NO, pyrimidine and C{sub 2}F{sub 4} over the same temperature range was studied as a function of pressure. Both attachment rate constants k{sub a} for NO and C{sub 2}F{sub 4}, and equilibrium constants K({double_bond}k{sub a}/k{sub d}) for CO{sub 2} and pyrimidine increased sharply at pressures of {chi}{sub T} peaks. Activation volumes V{sub a}* and reaction volumes {Delta}V{sub r} are very large and negative in the critical region. The volume change is mainly due to electrostriction around ions formed. The results are compared to volume changes predicted by, a compressible continuum model.
Date: July 1, 1999
Creator: Nishikawa, M.; Holroyd, R. A. & Itoh, K.
Object Type: Article
System: The UNT Digital Library
BENCH-SCALE DEMONSTRATION OF HOT-GAS DESULFURIZATION TECHNOLOGY (open access)

BENCH-SCALE DEMONSTRATION OF HOT-GAS DESULFURIZATION TECHNOLOGY

The U.S. Department of Energy (DOE), National Energy Technology Laboratory (NETL), is sponsoring research in advanced methods for controlling contaminants in hot coal gasifier gas (coal-derived fuel-gas) streams of integrated gasification combined-cycle (IGCC) power systems. The hot gas cleanup work seeks to eliminate the need for expensive heat recovery equipment, reduce efficiency losses due to quenching, and minimize wastewater treatment costs. Hot-gas desulfurization research has focused on regenerable mixed-metal oxide sorbents that can reduce the sulfur in coal-derived fuel-gas to less than 20 ppmv and can be regenerated in a cyclic manner with air for multicycle operation. Zinc titanate (Zn{sub 2}TiO{sub 4} or ZnTiO{sub 3}), formed by a solid-state reaction of zinc oxide (ZnO) and titanium dioxide (TiO{sub 2}), is currently one of the leading sorbents. Overall chemical reactions with Zn{sub 2}TiO{sub 4} during the desulfurization (sulfidation)-regeneration cycle are shown. The sulfidation/regeneration cycle can be carried out in a fixed-bed, moving-bed, or fluidized-bed reactor configuration. The fluidized-bed reactor configuration is most attractive because of several potential advantages including faster kinetics and the ability to handle the highly exothermic regeneration to produce a regeneration offgas containing a constant concentration of SO{sub 2}.
Date: July 1, 1999
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Beneficial Use of Drilling Waste - A Wetland Restoration Technology (open access)

Beneficial Use of Drilling Waste - A Wetland Restoration Technology

The results obtained thus far are promising with regard to the low toxicity of restored drill cuttings (particularly the Cameron substrate) with increasing levels of salinity. Water extraction, acid digestion, and interstitial water samples from the restored drill cuttings, as well as redox potential, soil pH and interstitial nitrate/ammonium concentrations, and the photosynthetic response, have been determined for the baseline fresh water condition (June-August 1998), at 9ppt (September-November 1998), at 18ppt (December-February 1998,1999), and at 27ppt (currently underway). Salinities will be brought to full-strength seawater (36ppt) on May 24, 1999. The Cameron drill cuttings are remarkably similar to dredge spoil, which is currently being used as a wetland creation substrate. The few elements that were extracted into the interstitial water were primarily cations (Ca, K, Mg) and were not elevated to a level that would pose a threat to wetlands productivity. Swaco drill cuttings remained high in aluminum with concomitant high pH, which likely resulted in limited plant productivity through hindered nutrient uptake.
Date: July 1, 1999
Creator: Pioneer Natural Resources
Object Type: Report
System: The UNT Digital Library
Bent solenoid simulations for the muon cooling experiment (open access)

Bent solenoid simulations for the muon cooling experiment

The muon collider captures pions using solenoidal fields. The pion are converted to muons as they are bunched in an RF phase rotation system. Solenoids are used to focus the muons as their emitance is reduced during cooling. Bent solenoids are used to sort muons by momentum. This report describes a bent solenoid system that is part of a proposed muon cooling experiment. The superconducting solenoid described in this report consists of a straight solenoid that is 1.8 m long, a bent solenoid that is 1.0 m to 1.3 m long and a second straight solenoid that is 2.6 m long. The bent solenoid bends the muons over an angle of 57.3 degrees (1 radian). The bent solenoid has a minor coil radius (to the center of the coil) that is 0.24 m and a major radius (of the solenoid axis) of 1.0 m. The central induction along the axis is 3.0 T There is a dipole that generates an induction of 0.51 T, perpendicular to the plane of the bend, when the induction on the bent solenoid axis is 3.0 T.
Date: July 9, 1999
Creator: Green, M. A.; Eyssa, Y. M.; Kenney, S.; Miller, J. R. & Prestemon, S.
Object Type: Article
System: The UNT Digital Library
Best Practices: Better Management of Technology Development Can Improve Weapon System Outcomes (open access)

Best Practices: Better Management of Technology Development Can Improve Weapon System Outcomes

A chapter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO assessed how best practices offer improvements to the way the Department of Defense (DOD) incorporates new technology into weapon system programs, focusing on: (1) the impact of technology maturity on product outcomes; (2) best practices for managing new technologies and incorporating them into products; and (3) ways DOD can adapt these practices to get better outcomes on weapon system programs."
Date: July 30, 1999
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Bexar County Long Range Financial Forecast: FY 1999-2000 through FY 2003-2004 (open access)

Bexar County Long Range Financial Forecast: FY 1999-2000 through FY 2003-2004

Long range financial forecast provides information to help decision-makers plan for the future financial needs of Bexar County; takes current expenditure levels, known cost increases, one-time expenses and inflation, and forecasts the effects of these factors on the County's financial condition for fiscal years 1999 through 2003.
Date: July 27, 1999
Creator: Bexar County (Tex.). Commissioners Court.
Object Type: Book
System: The Portal to Texas History
Beyond the Numbers, Volume 2, Number 3, July 1999 (open access)

Beyond the Numbers, Volume 2, Number 3, July 1999

Periodic paper series discussing information about occupational training, labor markets, and related information in Texas.
Date: July 1, 1999
Creator: Froeschle, Richard
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Bibliography of Work on the Heterogeneous Photocatalytic Removal of Hazardous Compounds from Water (open access)

Bibliography of Work on the Heterogeneous Photocatalytic Removal of Hazardous Compounds from Water

The subject of this report is chemistry and engineering for the application of heterogeneous photocatalysts. The state of the art in catalysts are forms of titanium dioxide or modifications thereof, but work on other heterogeneous catalysts is included.
Date: July 29, 1999
Creator: Blake, D. M.
Object Type: Report
System: The UNT Digital Library
Bioenergy Watershed Restoration in Regions of the West: What are the Environmental/Community Issues? (open access)

Bioenergy Watershed Restoration in Regions of the West: What are the Environmental/Community Issues?

Throughout the western mountainous regions, wildfire risks are elevated due to both fire suppression activities which have changed the forest structure making it more susceptible to stand-killing fires and the expansion of human structures (houses, light commercial) into these same forests, By providing a market for currently noncommercial but flammable materials (small trees, tops, and branches), new and existing bioenergy industries could be a key factor in reducing the regional forest fuel loads. Although bioenergy would appear to be an ideal answer to the problem in many ways, the situation is complicated and numerous issues need resolution. A public fearful of logging in these regions needs assurance that harvesting for bioenergy is an environmentally and socially responsible solution to the current fuel build up in these forests. This is especially important given that biomass harvesting cannot pay its own way under current energy market conditions and would have to be supported in some fashion.
Date: July 1, 1999
Creator: Graham, R.L.; Huff, D.D.; Kaufmann, M.R.; Shepperd, W.D. & Sheehan, J.
Object Type: Article
System: The UNT Digital Library
BIOMASS REBURNING - MEDELING/ENGINEERING STUDIES (open access)

BIOMASS REBURNING - MEDELING/ENGINEERING STUDIES

This project is designed to develop engineering and modeling tools for a family of NO{sub x} control technologies utilizing biomass as a reburning fuel. During the seventh reporting period (April 1--June 30, 1999), no information was received at EER on scheduled FETC R&D group's project activities. EER activities were on hold due to the pending purchase of the Niagara Mohawk's Dunkirk Station, a target demonstration site in this program, and then by the actual purchase of the Station by NRG. This report includes information about the current project status, recently submitted to NRG for soliciting their interest to proceed with biomass reburn demonstration, and notes on alternative demonstrative partners.
Date: July 30, 1999
Creator: Zamansky, Vladimir & Booth, Michael
Object Type: Report
System: The UNT Digital Library
The Blend Down Monitoring System Demonstration at the Paducah Gaseous Diffusion Plant (open access)

The Blend Down Monitoring System Demonstration at the Paducah Gaseous Diffusion Plant

Agreements between the governments of the US and the Russian Federation for the US purchase of low enriched uranium (LEU) derived from highly enriched uranium (HEU) from dismantled Russian nuclear weapons calls for the establishment of transparency measures to provide confidence that nuclear nonproliferation goals are being met. To meet these transparency goals, the agreements call for the installation of nonintrusive US instruments to monitor the down blending of HEU to LEU. The Blend Down Monitoring System (BDMS) has been jointly developed by the Los Alamos National Laboratory (LANL) and the Oak Ridge National Laboratory (ORNL) to continuously monitor {sup 235}U enrichments and mass flow rates at Russian blending facilities. Prior to its installation in Russian facilities, the BDMS was installed and operated in a UF{sub 6} flow loop in the Paducah Gaseous Diffusion Plant simulating flow and enrichment conditions expected in a typical down-blending facility. A Russian delegation to the US witnessed the equipment demonstration in June, 1998. To conduct the demonstration in the Paducah Gaseous Diffusion Plant (PGDP), the BDMS was required to meet stringent Nuclear Regulatory Commission licensing, safety and operational requirements. The Paducah demonstration was an important milestone in achieving the operational certification for the BDMS …
Date: July 25, 1999
Creator: Benton, J.; Close, D.; Johnson, W., Jr.; Kerr, P.; March-Leuba, J.; Mastal, E. et al.
Object Type: Article
System: The UNT Digital Library
Border Business Indicators, Volume 23, Number 7, July 1999 (open access)

Border Business Indicators, Volume 23, Number 7, July 1999

Monthly publication documenting statistics related to economic information in the Mexico-Texas border areas including types of border crossings, employment, customs revenues, and other related data.
Date: July 1999
Creator: Texas Center for Border Economic and Enterprise Development
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Budget FY2000: A Chronology with Internet Access (open access)

Budget FY2000: A Chronology with Internet Access

This report provides a select chronology of congressional and presidential actions and documents related to major budget events in calendar year 1999, covering the FY2000 budget. While the paper copy provides numerous Internet addresses, congressional offices can also use the Internet version of this report to access active links to appropriations and budget legislation, budget and economic data tables, pie charts, glossaries, selected testimony, publications, the President’s budget documents, and CRS products.
Date: July 27, 1999
Creator: Watkins, Susan E.
Object Type: Report
System: The UNT Digital Library
Budget Issues: Cap Structure and Guaranteed Funding (open access)

Budget Issues: Cap Structure and Guaranteed Funding

Testimony issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO discussed: (1) the budget structure and current budgetary control regime; (2) the budget outlook, discretionary caps, and enforcement situation as the United States enters an era of projected unified budget surpluses; (3) potential implications of guaranteeing minimum spending levels on the discretionary side of the budget; and (4) the pay-as-you-go (PAYGO) side of the equation: (a) permanent appropriations; (b) mandatory trust funds; and (c) mandatory special funds."
Date: July 21, 1999
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Building a dedicated information barrier system for warhead and sensitive item verification (open access)

Building a dedicated information barrier system for warhead and sensitive item verification

This paper documents the development of a dedicated information barrier system for warhead and sensitive item verification. The system the authors describe includes software and hardware information barriers used in conjunction with suitable procedures (or protocols) to achieve a high quality verification while minimizing intrusiveness and preventing transfer of sensitive data to inspectors. The system they describe has been referred to as CIVET--Controlled Intrusiveness Verification Technology and has been implemented to verify warheads and warhead components during various exercises and demonstrations under the auspices of the Department of Energy (DOE) and the Department of Defense (DOD).
Date: July 25, 1999
Creator: ZUHOSKI,P.B.; INDUSI,J.P. & VANIER,P.E.
Object Type: Article
System: The UNT Digital Library
BUSFET - A Novel Radiation-Hardened SOI Transistor (open access)

BUSFET - A Novel Radiation-Hardened SOI Transistor

The total-dose hardness of SOI technology is limited by radiation-induced charge trapping in gate, field, and SOI buried oxides. Charge trapping in the buried oxide can lead to back-channel leakage and makes hardening SOI transistors more challenging than hardening bulk-silicon transistors. Two avenues for hardening the back-channel are (1) to use specially prepared SOI buried oxides that reduce the net amount of trapped positive charge or (2) to design transistors that are less sensitive to the effects of trapped charge in the buried oxide. In this work, we propose a new partially-depleted SOI transistor structure that we call the BUSFET--Body Under Source FET. The BUSFET utilizes a shallow source and a deep drain. As a result, the silicon depletion region at the back channel caused by radiation-induced charge trapping in the buried oxide does not form a conducting path between source and drain. Thus, the BUSFET structure design can significantly reduce radiation-induced back-channel leakage without using specially prepared buried oxides. Total dose hardness is achieved without degrading the intrinsic SEU and dose rate hardness of SOI technology. The effectiveness of the BUSFET structure for reducing total-dose back-channel leakage depends on several variables, including the top silicon film thickness and doping …
Date: July 20, 1999
Creator: Schwank, J.R.; Shaneyfelt, M.R.; Draper, B.L. & Dodd, P.E.
Object Type: Article
System: The UNT Digital Library
Calculation of drift seepage for alternative emplacementdesigns (open access)

Calculation of drift seepage for alternative emplacementdesigns

The calculations presented in this report are performed to obtain seepage rates into drift and boreholes for two alternative designs of drift and waste emplacement at Yucca Mountain. The two designs are defined according to the Scope of Work 14012021M1, activity 399621, drafted October 6, 1998, and further refined in a conference telephone call on October 13, 1998, between Mark Balady, Jim Blink, Rob Howard and Chin-Fu Tsang. The 2 designs considered are: (1) Design A--Horizontal boreholes 1.0 m in diameter on both sides of the drift, with each borehole 8 m long and inclined to the drift axis by 30 degrees. The pillar between boreholes, measured parallel to the drift axis, is 3.3 m. In the current calculations, a simplified model of an isolated horizontal borehole 8 m long will be simulated. The horizontal borehole will be located in a heterogeneous fracture continuum representing the repository layer. Three different realizations will be taken from the heterogeneous field, representing three different locations in the rock. Seepage for each realization is calculated as a function of the percolation flux. Design B--Vertical boreholes, 1.0 m in diameter and 8.0 m deep, drilled from the bottom of an excavated 8.0 m diameter drift. …
Date: July 30, 1999
Creator: Li, Guomin; Tsang, Chin-Fu & Birkholzer, Jens
Object Type: Report
System: The UNT Digital Library
Calibration of seismic wave propagation in Jordan (open access)

Calibration of seismic wave propagation in Jordan

The Natural Resources Authority of Jordan (NRA), the USGS and LLNL have a collaborative project to improve the calibration of seismic propagation in Jordan and surrounding regions. This project serves common goals of CTBT calibration and earthquake hazard assessment in the region. These objectives include accurate location of local and regional earthquakes, calibration of magnitude scales, and the development of local and regional propagation models. In the CTBT context, better propagation models and more accurately located events in the Dead Sea rift region can serve as (potentially GT5) calibration events for generating IMS location corrections. The detection and collection of mining explosions underpins discrimination research. The principal activity of this project is the deployment of two broadband stations at Hittiyah (south Jordan) and Ruweishid (east Jordan). These stations provide additional paths in the region to constrain structure with surface wave and body wave tomography. The Ruweishid station is favorably placed to provide constraints on Arabian platform structure. Waveform modeling with long-period observations of larger earthquakes will provide constraints on 1-D velocity models of the crust and upper mantle. Data from these stations combined with phase observations from the 26 short-period stations of the Jordan National Seismic Network (JNSN) may allow …
Date: July 23, 1999
Creator: Al-Husien, A.; Amrat, A.; Harris, D.; Mayeda, K.; Nakanishi, K.; Rodgers, A. et al.
Object Type: Article
System: The UNT Digital Library
Calibration of seismic wave propagation in Kuwait (open access)

Calibration of seismic wave propagation in Kuwait

The Kuwait Institute of Scientific Research (KISR), the USGS and LLNL are collaborating to calibrate seismic wave propagation in Kuwait and surrounding regions of the northwest Arabian Gulf using data from the Kuwait National Seismic Network (KNSN). Our goals are to develop local and regional propagation models for locating and characterizing seismic events in Kuwait and portions of the Zagros mountains close to Kuwait. The KNSN consists of 7 short-period stations and one broadband (STS-2) station. Constraints on the local velocity structure may be derived from joint inversions for hypocenters of local events and the local velocity model, receiver functions from three-component observations of teleseisms, and surface wave phase velocity estimated from differential dispersion measurements made across the network aperture. Data are being collected to calibrate travel-time curves for the principal regional phases for events in the Zagros mountains. The available event observations span the distance range from approximately 2.5 degrees to almost 9 degrees. Additional constraints on structure across the deep sediments of the Arabian Gulf will be obtained from long-period waveform modeling.
Date: July 23, 1999
Creator: Al-Awadhi, J.; Endo, E.; Fryall, F.; Harris, D.; Mayeda, K.; Rodgers, A. et al.
Object Type: Article
System: The UNT Digital Library
Calibration Procedures for a Two-Modulator Generalized Ellipsometer (open access)

Calibration Procedures for a Two-Modulator Generalized Ellipsometer

A Two-Modulator Generalized Ellipsometer (2-MGE) has been extremely useful in characterizing optical properties of uniaxial bulk materials, thin films and diffraction gratings. The instrument consists of two polarizer-photoelastic modulator pairs, one operating as the polarization state generator and the other as the polarization state detector. Each photoelastic modulator operates at a different remnant frequency (such as 50 kHz and 60 kHz), making it possible to measure eight elements of the reduced sample Mueller matrix simultaneously. In certain configurations, light reflection from non-depolarizing anisotropic samples can be completely characterized by a single measurement, and the entire reduced Jones matrix can be determined, including the cross polarization coefficients. The calibration of the instrument involves the measurement of the azimuthal angle of the polarizer with respect to the modulator, the modulation amplitude, and the modulator strain for each polarizer photoelastic modulator pair, where the last two are functions of wavelengths. In addition, it is essential to calibrate the azimuthal angles of the polarization state generator and the polarization state detector with respect to the plane of incidence in the ellipsometry configuration that is used in the measurements. Because two modulators operating at different frequencies are used, these calibrations are actually easier and more …
Date: July 18, 1999
Creator: Chen, C.; Jellison, G. E., Jr. & Modine, F.A.
Object Type: Article
System: The UNT Digital Library