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Progress and Critical Issues for IFE Blanket and Chamber Research
Advances in high gain target designs for Inertial Fusion Energy (IFE), and the initiation of construction of large megajoule-class laser facilities in the U.S. (National Ignition Facility) and France (Laser-Megajoule) capable of testing the requirements for inertial fusion ignition and propagating burn, have improved the prospects for IFE. Accordingly, there have recently been modest increases in the US fusion research program related to the feasibility of IFE. These research areas include heavy-ion accelerators, Krypton-Fluoride (KrF) gas lasers, diode-pumped, solid-state (DPSSL) lasers, IFE target designs for higher gains, feasibility of low cost IFE target fabrication and accurate injection, and long-lasting IFE fusion chambers and final optics. Since several studies of conceptual IFE power plant and driver designs were completed in 1992-1996 [1-5], U.S. research in the IFE blanket, chamber, and target technology areas has focused on the critical issues relating to the feasibility of IFE concepts towards the goal of achieving economically-competitive and environmentally-attractive fusion energy. This paper discusses the critical issues in these areas, and the approaches taken to address these issues. The U.S. research in these areas, called IFE Chamber and Target Technologies, is coordinated through the Virtual Laboratory for Technology (VLT) formed by the Department of Energy in …
Date:
June 23, 1999
Creator:
Abdou, M.; Kulcinski, G. L.; Latkowski, J. F.; Logan, B. G.; Meier, W. R.; Moir, R. W. et al.
Object Type:
Article
System:
The UNT Digital Library
Pattern of Thermal Fluctuations in a Recovery Boiler Floor
The floor of a black liquor recovey boiler at a mill in central Canada has experienced cracking and delamination of the composite tubing near the spout wall and deformation of the floor panels that is most severe in the vicinity of the spout wall. One possible explanation for the observed damage is impacts of salt cake falling from the convective section onto the floor. In order to determine if such impacts do occur, strain gauges and thermocouples were installed on the boiler floor in areas where cracking and deformation were most frequent. The data obtained from these instruments indicate that brief, sudden temperature fluctuations do occur, and changes in the strain experienced by the affected tube occur simultaneously. These fluctuations appear to occur less often along the spout wall and more frequently with increasing distance from the wall. The frequency of these temperature fluctuations is insufficient for thermal fatigue to be the sole cause of the cracking observed on the tubes, but the data are consistent with what might be expected from pieces of falling salt cake.
Date:
April 25, 1999
Creator:
Abdullah, Z.; Gorog, J. P.; Keiser, J. R.; Meyers, L. E. & Swindeman, R. W.
Object Type:
Article
System:
The UNT Digital Library
Direct Measurement of A{sub c} using Inclusive Charm Tagging at the SLD Detector
We report a new measurement of A{sub c} using data obtained by SLD in 1993-98. This measurement uses a vertex tag technique, where the selection of a c hemisphere is based on the reconstructed mass of the charm hadron decay vertex. The method uses the 3D vertexing capabilities of SLD's CCD vertex detector and the small and stable SLC beams to obtain a high c-event tagging efficiency and purity of 28% and 82%, respectively. Charged kaons identified by the CRID detector and the charge of the reconstructed vertex provide an efficient quark-antiquark tag, with the analyzing power calibrated from the data. We obtain a preliminary result of A{sub c} = 0.603 {+-} 0.028 {+-} 0.023.
Date:
July 14, 1999
Creator:
Abe, K
Object Type:
Report
System:
The UNT Digital Library
New Measurement of A{sub b} at the Z{sup 0} Resonance Using a Vertex Charge Technique
We present a new preliminary measurement of the parity-violation parameter A{sub b} using a self-calibrating vertex-charge technique. In the SLD experiment we observe hadronic decays of Z{sup 0} bosons produced in collisions between longitudinally polarized electrons and unpolarized positrons at the SLAC Linear Collider. A sample of b{bar b} events is selected using the topologically reconstructed mass of B hadrons. From our 1996-1998 data sample of approximately 400,000 hadronic Z{sup 0} decays, we obtain A{sub b} = 0.897 {+-} 0.027(stat){sub -0.034}{sup +0.036}(syst).
Date:
July 20, 1999
Creator:
Abe, K
Object Type:
Report
System:
The UNT Digital Library
Current Performance of the SLD VXD3
During 1996, the SLD collaboration completed construction and began operation of a new charge-coupled device (CCD) vertex detector (VXD3). Since then, its performance has been studied in detail and a new topological vertexing technique has been developed. In this paper, we discuss the design of VXD3, procedures for aligning it, and the tracking and vertexing improvements that have led to its world-record performance.
Date:
September 14, 1999
Creator:
Abe, Toshinori
Object Type:
Report
System:
The UNT Digital Library
An Improved Direct Measurement of Leptonic Coupling Asymmetries with Polarized Z{sup 0}'s
We report new direct measurements of the Z{sup 0}-lepton coupling asymmetry parameters A{sub e}, A{sub {mu}} and A{sub r}, with polarized Z{sup 0}'s collected by the SLD detector at the SLAC Linear Collider. The parameters are extracted from the measurement of the left-right-forward-backward asymmetries for each lepton species. The 1996, 1997 and 1998 SLD runs are included in this analysis and combined with published data from the 1993-95 runs. Preliminary results are A{sub e} = 0.1558 {+-} 0.0064, A{sub {mu}} = 0.137 {+-} 0.016 and A{sub {tau}} = 0.142 {+-} 0.016. If lepton universality is assumed, a combined asymmetry parameter A{sub l} = 0.1523 {+-} 0.0057 results. This translates into an effective weak mixing angle sin{sup 2} {theta}{sub W}{sup eff} = 0.23085 {+-} 0.00073 at the Z{sup 0} resonance.
Date:
August 3, 1999
Creator:
Abe, Toshinori
Object Type:
Report
System:
The UNT Digital Library
A Preliminary measurement of the gluon splitting rate into b\bar{b} pairs in hadronic Z0 decays
We present a measurement of the rate of gluon splitting into bottom quarks, g --> b anti-b, in hadronic Z<sup>0</sup> decays collected by SLD from 1996 to 1998. The analysis was performed by looking for secondary bottom production in 4-jet events of any primary avor. A topological vertex mass technique was used to tag the two jets with the smallest angle between them as b/anti-b. We obtained a rate of g --> b anti-b per hadronic event to be (3.07 ± 0.71(stat:) ± 0.66(syst:)) × 10³ (preliminary).
Date:
June 10, 1999
Creator:
Abe, Toshinori
Object Type:
Report
System:
The UNT Digital Library
Electricity Restructuring Background: Public Utility Holding Company Act of 1935 (PUHCA)
This report provides background information on PUHCA, including its history and impact. It also discusses how PUHCA reform fits into the current electric utility industry restructuring debate. This report will be updated as events warrant. For related information on electricity restructuring, see the CRS Electronic Briefing Book.
Date:
January 7, 1999
Creator:
Abel, Amy
Object Type:
Report
System:
The UNT Digital Library
Development of a Real-Time Beryllium Air Monitor Utilizing Microwave Induced Plasma Spectroscopy (MIPAES)
This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) Program Development project at the Los Alamos National laboratory (LANL). The focus of this development has been an innovative beryllium air monitor for on-site' real-time continuous monitoring which overcomes limitations of the previous techniques for beryllium monitoring. A bench-top instrument has been set up and the performance of the instrument has been tested based on a solution aerosol. The sensitivity obtained with the instrument is sufficient to ensure workers can respond at airborne levels well below current exposure regulations. With this versatile, real-time monitor, worker exposure can be greatly reduced.
Date:
July 16, 1999
Creator:
Abeln, S.; Duan, Y.-A.; Olivares, J. A.; Koby, M. & Scopsick, R. C.
Object Type:
Report
System:
The UNT Digital Library
Growth and Fabrication of GaN/AlGaN Heterojunction Bipolar Transistor
A GaN/AlGaN heterojunction bipolar transistor structure with Mg doping in the base and Si Doping in the emitter and collector regions was grown by Metal Organic Chemical Vapor Deposition in c-axis Al(2)O(3). Secondary Ion Mass Spectrometry measurements showed no increase in the O concentration (2-3x10(18) cm(-3)) in the AlGaN emitter and fairly low levels of C (~4-5x10(17) cm (-3)) throughout the structure. Due to the non-ohmic behavior of the base contact at room temperature, the current gain of large area (~90 um diameter) devices was <3. Increasing the device operating temperature led to higher ionization fractions of the mg acceptors in the base, and current gains of ~10 were obtained at 300 degree C.
Date:
March 16, 1999
Creator:
Abernathy, C. R.; Baca, A. G.; Cao, X. A.; Cho, H.; Dang, G. T.; Donovan, S. M. et al.
Object Type:
Article
System:
The UNT Digital Library
Behavior of W and WSi(x) Contact Metallization on n- and p- Type GaN
Sputter-deposited W-based contacts on p-GaN (N{sub A} {approximately} 10{sup 18} cm{sup {minus}3}) display non-ohmic behavior independent of annealing temperature when measured at 25 C. The transition to ohmic behavior occurs above {approximately} 250 C as more of the acceptors become ionized. The optimum annealing temperature is {approximately} 700 C under these conditions. These contacts are much more thermally stable than the conventional Ni/Au metallization, which shows a severely degraded morphology even at 700 C. W-based contacts may be ohmic as-deposited on very heavily doped n-GaN, and the specific contact resistance improves with annealing up to {approximately} 900 C.
Date:
January 5, 1999
Creator:
Abernathy, C. R.; Cao, X. A.; Cole, M. W.; Eizenberg, M.; Lothian, J. R.; Pearton, S. J. et al.
Object Type:
Article
System:
The UNT Digital Library
Wet Chemical Etching Survey of III-Nitrides
Wet chemical etching of GaN, InN, AlN, InAlN and InGaN was investigated in various acid and base solutions at temperatures up to 75 C. Only KOH-based solutions were found to etch AlN and InAlN. No etchants were found for the other nitrides, emphasizing their extreme lack of chemical reactivity. The native oxide on most of the nitrides could be removed in potassium tetraborate at 75 C, or HCl/H{sub 2}O at 25 C.
Date:
February 4, 1999
Creator:
Abernathy, C. R.; Cho, H.; Hays, D. C.; MacKenzie, J. D.; Pearton, S.J.; Ren, F. et al.
Object Type:
Article
System:
The UNT Digital Library
Inductively Coupled Plasma Etching of III-Nitrides in Cl(2)/Xe,Cl(2)/Ar and Cl(2)/He
The role of additive noble gases He, Ar and Xe to C&based Inductively Coupled Plasmas for etching of GaN, AIN and InN were examined. The etch rates were a strong function of chlorine concentration, rf chuck power and ICP source power. The highest etch rates for InN were obtained with C12/Xe, while the highest rates for AIN and GaN were obtained with C12/He. Efficient breaking of the 111-nitrogen bond is crucial for attaining high etch rates. The InN etching was dominated by physical sputtering, in contrast to GaN and AIN. In the latter cases, the etch rates were limited by initial breaking of the III-nitrogen bond. Maximum selectivities of -80 for InN to GaN and InN to AIN were obtained.
Date:
January 5, 1999
Creator:
Abernathy, C.R.; Cho, H.; Donovan, S.M.; Hahn, Y.B.; Hays, D.C.; Jung, K.B. et al.
Object Type:
Article
System:
The UNT Digital Library
MCNP-REN - A Monte Carlo Tool for Neutron Detector Design Without Using the Point Model
The development of neutron detectors makes extensive use of the predictions of detector response through the use of Monte Carlo techniques in conjunction with the point reactor model. Unfortunately, the point reactor model fails to accurately predict detector response in common applications. For this reason, the general Monte Carlo N-Particle code (MCNP) was modified to simulate the pulse streams that would be generated by a neutron detector and normally analyzed by a shift register. This modified code, MCNP - Random Exponentially Distributed Neutron Source (MCNP-REN), along with the Time Analysis Program (TAP) predict neutron detector response without using the point reactor model, making it unnecessary for the user to decide whether or not the assumptions of the point model are met for their application. MCNP-REN is capable of simulating standard neutron coincidence counting as well as neutron multiplicity counting. Measurements of MOX fresh fuel made using the Underwater Coincidence Counter (UWCC) as well as measurements of HEU reactor fuel using the active neutron Research Reactor Fuel Counter (RRFC) are compared with calculations. The method used in MCNP-REN is demonstrated to be fundamentally sound and shown to eliminate the need to use the point model for detector performance predictions.
Date:
July 25, 1999
Creator:
Abhold, M.E. & Baker, M.C.
Object Type:
Article
System:
The UNT Digital Library
Depth Measurement of Moving Slurry at the Wet End of a Paper Machine
The paper industry has long had a need to better understand and control its papermaking process upstream, specifically at the wet end in the forming section of a paper machine. A vision-based system is under development that addresses this need by automatically measuring and interpreting the pertinent paper web parameters at the wet end in real time. The wet-end characterization of the paper web by a vision system involves a four-dimensional measurement of the slurry in real time. These measurements include the two-dimensional spatial information, the intensity profile, and the depth profile. This paper describes the real-time depth profile measurement system for the high-speed moving slurry. A laser line-based measurement method is used with a high-speed programmable camera to directly measure slurry height. The camera is programmed with a profile algorithm, producing depth data at fast sampling rates. Analysis and experimentation have been conducted to optimize the system for the characteristics of the slurry and laser line image. On-line experimental results are presented.
Date:
January 24, 1999
Creator:
Abidi, B. R.; Goddard, J. S., Jr.; Hunt, M. A.; Sari-Sarraf, H. & Turner, J. C.
Object Type:
Article
System:
The UNT Digital Library
Surface Characterization of a Paper Web at the Wet End
We present an algorithm for the detection and representation of structures and non-uniformities on the surface of a paper web at the wet end (slurry). This image processing/analysis algorithm is developed as part of a complete on-line web characterization system. Images of the slurry, carried by a fast moving table, are obtained using a stroboscopic light and a CCD camera. The images have very poor contrast and contain noise from a variety of sources. Those sources include the acquisition system itself, the lighting, the vibrations of the moving table being imaged, and the scattering water from the same table's movement. After many steps of enhancement, conventional edge detection methods were still inconclusive and were discarded. The facet model algorithm, is applied to the images and is found successful in detecting the various topographic characteristics of the surface of the slurry. Pertinent topographic elements are retained and a filtered image is computed based on the general appearance and characteristics of the structures in question. Morphological operators are applied to detect and segment regions of interest. Those regions are then filtered according to their size, elongation, and orientation.Their bounding rectangles are computed and superimposed on the original image. Real time implementation of …
Date:
June 23, 1999
Creator:
Abidi, B.R.; Goddard, J.S. & Sari-Sarraf, H.
Object Type:
Article
System:
The UNT Digital Library
Facet Model and Mathematical Morphology for Surface Characterization
This paper describes an algorithm for the automatic segmentation and representation of surface structures and non-uniformities in an industrial setting. The automatic image processing and analysis algorithm is developed as part of a complete on-line web characterization system of a papermaking process at the wet end. The goal is to: (1) link certain types of structures on the surface of the web to known machine parameter values, and (2) find the connection between detected structures at the beginning of the line and defects seen on the final product. Images of the pulp mixture (slurry), carried by a fast moving table, are obtained using a stroboscopic light and a CCD camera. This characterization algorithm succeeded where conventional contrast and edge detection techniques failed due to a poorly controlled environment. The images obtained have poor contrast and contain noise caused by a variety of sources. After a number of enhancement steps, conventional segmentation methods still f ailed to detect any structures and are consequently discarded. Techniques tried include the Canny edge detector, the Sobel, Roberts, and Prewitt's filters, as well as zero crossings. The facet model algorithm, is then applied to the images with various parameter settings and is found to be …
Date:
November 13, 1999
Creator:
Abidi, B.R.; Goddard, J.S.; Hunt, M.A. & Sari-Sarraf, H.
Object Type:
Article
System:
The UNT Digital Library
[Abilene City Council Minutes: 1999]
Ledger containing minutes of the City Council in Abilene, Texas documenting the group's discussions and activities from January 14, 1999 to December 16, 1999.
Date:
1999-01-14/1999-12-16
Creator:
Abilene (Tex.)
Object Type:
Book
System:
The Portal to Texas History
[Abilene City Ordinances: 1999]
Ledger containing ordinances/resolutions passed by the city of Abilene, Texas during calendar year 1999.
Date:
1999
Creator:
Abilene (Tex.)
Object Type:
Legal Document
System:
The Portal to Texas History
[Abilene City Resolutions: 1999]
Ledger containing resolutions passed by the city of Abilene, Texas during calendar year 1999.
Date:
1999
Creator:
Abilene (Tex.)
Object Type:
Legal Document
System:
The Portal to Texas History
[Program: Crazy for You, 1999]
Program for a production of Crazy for You at Abilene Christian University performed at the Abilene Civic Center Theatre from October 22nd to 24th, 1999. It includes a list of cast and staff, and other information about the play.
Date:
1999
Creator:
Abilene Christian College
Object Type:
Pamphlet
System:
The Portal to Texas History
Catalog of Abilene Christian University, 1999-2000
Undergraduate catalog describes the governance, history, academic programs, course descriptions, and campus life of Abilene Christian University in Abilene, Texas.
Date:
1999
Creator:
Abilene Christian University
Object Type:
Book
System:
The Portal to Texas History
Prickly Pear, Yearbook of Abilene Christian University, 1999
Yearbook for Abilene Christian University in Abilene, Texas includes photos of and information about the school, student body, professors, and organizations. Index starts on page 300.
Date:
1999
Creator:
Abilene Christian University
Object Type:
Yearbook
System:
The Portal to Texas History
The Shinnery Review, 1999
The Shinnery Review literary magazine of Abilene Christian University includes original short stories, essays, poetry, artwork, and other creative works.
Date:
1999
Creator:
Abilene Christian University
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History