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A 1 MEGAWATT POLYPHASE BOOST CONVERTER-MODULATOR FOR KLYSTRON PULSE APPLICATION
This paper describes electrical design criteria and first operational results a 140 kV, 1 MW average, 11 MW peak, zero-voltage-switching 20 kHz polyphase bridge, boost converter/modulator for klystron pulse application. The DC-DC converter derives the buss voltages from a standard 13.8 kV to 2300 Y substation cast-core transformer. Energy storage and filtering is provided by self-clearing metallized hazy polypropylene traction capacitors. Three ''H-Bridge'' Insulated Gate Bipolar Transistor (IGBT) switching networks are used to generate the polyphase 20 kHz transformer primary drive waveforms. The 20 kHz drive waveforms are chirped the appropriate duration to generate the desired klystron pulse width. PWM (pulse width modulation) of the individual 20 kHz pulses is utilized to provide regulated output waveforms with adaptive feedforward and feedback techniques. The boost transformer design utilizes amorphous nanocrystalline material that provides the required low core loss at design flux levels and switching frequencies. Resonant shunt-peaking is used on the transformer secondary to boost output voltage and resonate transformer leakage inductance. With the appropriate transformer leakage inductance and peaking capacitance, zero-voltage-switching of the IGBT's is attained, minimizing switching losses. A review of these design parameters and the first results of the performance characteristics will be presented.
Date:
June 1, 2001
Creator:
Reass, W. A.; Doss, J. D. & Gribble, R. F.
Object Type:
Article
System:
The UNT Digital Library
10 (micro)m and 5 (micro)m Pinhole-Assisted Point-Projection Backlit Imaging for NIF
Pinhole-assisted point-projection backlighting with 10{micro}m and 5 {micro}m pinholes placed a small distance of order 1 mm away from the backlighter produces images with large field of view and high resolution. Pinholes placed closely to high-power backlighter sources can vaporize and close due to x-ray driven ablation, thereby limiting the usefulness of this method. A study of streaked 1-D backlit imaging of 25 {micro}m W wires using the OMEGA laser is presented. The pinhole closure timescale for 10 {micro}m pinholes placed 0.45 mm and 1 mm distant from the backlighter is 1.3 ns and 2.2 ns, respectively. Similar timescales for 5 {micro}m pinholes is also presented. Successful wire imaging prior to pinhole closure is clearly demonstrated.
Date:
June 5, 2001
Creator:
Bullock, A. B.; Landen, O. L. & Bradley, D. K.
Object Type:
Article
System:
The UNT Digital Library
17th Edition of TOP500 List of World's Fastest SupercomputersReseased
17th Edition of TOP500 List of World's Fastest Supercomputers Released MANNHEIM, GERMANY; KNOXVILLE, TENN.; BERKELEY, CALIF. In what has become a much-anticipated event in the world of high-performance computing, the 17th edition of the TOP500 list of the world's fastest supercomputers was released today (June 21). The latest edition of the twice-yearly ranking finds IBM as the leader in the field, with 40 percent in terms of installed systems and 43 percent in terms of total performance of all the installed systems. In second place in terms of installed systems is Sun Microsystems with 16 percent, while Cray Inc. retained second place in terms of performance (13 percent). SGI Inc. was third both with respect to systems with 63 (12.6 percent) and performance (10.2 percent).
Date:
June 21, 2001
Creator:
Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack J. & Simon,Horst D.
Object Type:
Report
System:
The UNT Digital Library
2nd Feasibility Study of a Muon Storage Ring Neutrino Factory
The design and simulated performance of a second feasibility study are presented. The efficiency of producing muons is {approx} 0.17 {micro}/p with 24 GeV protons. This study was sponsored by the BNL Director, with BNL site specific driver and layout. It was a follow on to the First Study[2] sponsored by the Fermilab Director, with Fermilab site specific driver and layout, and was the main US collaboration conceptual effort during the past year. Other studies, and technical work by the collaboration is reported in other papers.
Date:
June 18, 2001
Creator:
Ozaki, S.; Palmer, R. B. & Zisman, M. S.
Object Type:
Article
System:
The UNT Digital Library
Accelerator Physics Issues for Future Electron Ion Colliders
Interest continues to grow in the physics of collisions between electrons and heavy ions, and between polarized electrons and polarized protons [1,2,3]. Table 1 compares the parameters of some machines under discussion. DESY has begun to explore the possibility of upgrading the existing HERA-p ring to store heavy ions, in order to collide them with electrons (or positrons) in the HERA-e ring, or from TESLA [4]. An upgrade to store polarized protons in the HERA-p ring is also under discussion [1]. BNL is considering adding polarized electrons to the RHIC repertoire, which already includes heavy and light ions, and polarized protons. The authors of this paper have made a first pass analysis of this ''eRHIC'' possibility [5]. MIT-BATES is also considering electron ion collider designs [6].
Date:
June 18, 2001
Creator:
Peggs, S.; Ben-Zvi, Ilan; Kewisch, J. & Murphy, J.
Object Type:
Article
System:
The UNT Digital Library
Accuracy of Projection Methods for the Incompressible Navier-Stokes Equations
Numerous papers have appeared in the literature over the past thirty years discussing projection-type methods for solving the incompressible Navier-Stokes equations. A recurring difficulty encountered is the choice of boundary conditions for the intermediate or predicted velocity in order to obtain at least second order convergence. A further issue is the formula for the pressure correction at each timestep. A simple overview is presented here based on recently published results by Brown, Cortez and Minion [2].
Date:
June 12, 2001
Creator:
Brown, D L
Object Type:
Article
System:
The UNT Digital Library
Acoustic Monitor for Liquid Solid Slurries Measurements at Low Weight Fractions
The principal objective of the project is to develop an acoustic probe for determining the volume fraction of particles in a flowing suspension. This will include testing the theory of acoustic wave propagation in suspensions and demonstrating the application of the probe by installing it on a flow loop through which a suspension is flowing and determining the particle volume fraction. The signal from the probe must be processed such that the noise arising from the presence of the gas bubbles, if present in the system, is removed to yield an accurate estimate of the particle volume fraction. Once the probe is developed and tested successfully at Syracuse University, it is to be installed and tested in the flow loop at Oak Ridge National Laboratories for surrogate slurries for the Hanford Nuclear site. Particular attention is to be given to testing suspensions with low particle volume fractions since slurries to be transported in nuclear waste processing will have low particle volume fractions.
Date:
June 1, 2001
Creator:
Taularides, L. L. & Sangani, A.
Object Type:
Report
System:
The UNT Digital Library
Acquisition of building geometry in the simulation of energy performance
Building geometry is essential to any simulation of building performance. This paper examines the importing of building geometry into simulation of energy performance from the users' point of view. It lists performance requirements for graphic user interfaces that input building geometry, and discusses the basic options in moving from two- to three-dimensional definition of geometry and the ways to import that geometry into energy simulation. The obvious answer lies in software interoperability. With the BLIS group of interoperable software one can interactively import building geometry from CAD into EnergyPlus and dramatically reduce the effort otherwise needed for manual input.The resulting savings may greatly increase the value obtained from simulation, the number of projects in which energy performance simulation is used, and expedite decision making in the design process.
Date:
June 28, 2001
Creator:
Bazjanac, Vladimir
Object Type:
Article
System:
The UNT Digital Library
Acquisition of Leased Space for the U.S. Patent and Trademark Office
Correspondence issued by the General Accounting Office with an abstract that begins "This report reviews the data, assumptions, and conclusions reached by the General Services Administration (GSA) and the Patent and Trademark Office (PTO) on the acquisition of about two million square feet of leased space for the consolidation of PTO activities. This build-to-suit lease, valued at approximately $1.2 billion over its 20-year term, was signed in June 2000. this report responds to allegations and questions from two public interest groups about the PTO lease acquisition. One public interest group alleged that during the procurement process for the lease (1) GSA improperly awarded the lease to an offeror who had not complied with the solicitation's stated requirements, (2) GSA failed to compete the construction of the interior finishes phase of the project as required by law, and (3) GSA used an illegal cost-plus-a-percentage-of-cost contract. The second public interest group asked (1) whether the requirements in GSA's Solicitation for Offers for the PTO lease transformed the lease from an operating lease to a capital lease under Office of Management and Budget (OMB) Circular A-11; (2) whether the new facility will be able to house all PTO employees and contractors throughout the …
Date:
June 5, 2001
Creator:
United States. General Accounting Office.
Object Type:
Text
System:
The UNT Digital Library
ACTINIDE-ALUMINATE SPECIATION IN ALKALINE RADIOACTIVE WASTE
Highly alkaline radioactive waste tanks contain a number of transuranic species, in particular U, Np, Pu, and Am--the exact forms of which are currently unknown. Knowledge of actinide speciation under highly alkaline conditions is essential towards understanding and predicting their solubility and sorption behavior in tanks, determining whether chemical separations are needed for waste treatment, and designing separations processes. Baseline washing of tank sludges with NaOH solutions is being proposed to reduce the volume of HLW. Alkaline pretreatment of HLW will be needed to remove aluminum [as NaAl(OH){sub 4}] because it significantly reduces the HLW volume; however, aluminate [Al(OH){sub 4}{sup -}] enhances actinide solubility via an unknown mechanism. Thus, alkaline wash residues may require an additional treatment to remove actinides. The results of this research will determine the nature TRU (Np, Pu, Am) speciation with aluminate anions under alkaline, oxidizing tank-like conditions. Specific issues to be addressed include solubility of these actinides, speciation in aluminate-containing alkaline supernatants, the role of actinide redox states on solubility, and partitioning between supernatant and solid phases, including colloids. Studies will include thermodynamics, kinetics, spectroscopy, electrochemistry, etc. It is already known, for example, that certain high valent forms of NF and Pu are very soluble …
Date:
June 1, 2001
Creator:
Clark-Deaborg, David
Object Type:
Report
System:
The UNT Digital Library
Adaptive response against spontaneous neoplastic transformation induced by low dose ionizing radiation
This project is being conducted to ascertain the shape of the dose response curve for neoplastic transformation in vitro over the dose range 0.0 to 10 cGy, and to determine how this depends on radiation quality and dose fractionation. Preliminary data already have indicated that at a dose of 1 cGy the induced transformation frequency is less than the spontaneous transformation frequency. The results will be compared with animal and human epidemiological data on the induction of cancer by low doses of radiation. This will hopefully allow for a more informed estimation of the risk of cancer induction at low doses.
Date:
June 1, 2001
Creator:
Redpath, J. Leslie
Object Type:
Report
System:
The UNT Digital Library
Addendum to Revision 1 of the Corrective Action Investigation Plan for Corrective Action Unit 98: Frenchman Flat, Nevada Test Site, Nevada (Addendum Revision No. 1)
This document is submitted as an addendum to the Corrective Action Investigation Plan (CAIP) for Corrective Action Unit (CAU) 98: Frenchman Flat, Nevada Test Site (NTS), Nevada. The addendum was prepared to propose work activities in response to comments resulting from the U.S. Department of Energy's (DOE's) review of the draft Frenchman Flat CAU model of groundwater flow and contaminant transport completed in April 1999. The reviewers included an external panel of experts and the Nevada Division of Environmental Protection. As a result of the review, additional work scope, including new data-collection and modeling activities, has been identified for the Frenchman Flat CAU. The proposed work scope described in this addendum will be conducted in accordance with the revised Underground Test Area strategy contained in the December 2000 amendment to the Federal Facility Agreement and Consent Order. The Frenchman Flat CAU model is a group of interdependent models designed to predict the extent of contamination in groundwater due to the underground nuclear tests conducted within this CAU. At the time of the DOE review, the CAU model consisted of a CAU groundwater flow and transport model comprised of two major components: a groundwater flow model and a recharge model. The …
Date:
June 6, 2001
Creator:
U.S. Department of Energy, National Nuclear Security Administration Nevada Operations Office
Object Type:
Report
System:
The UNT Digital Library
Adjustable permanent quadrupoles for the next linear collider
The proposed Next Linear Collider (NLC) will require over 1400 adjustable quadrupoles between the main linacs' accelerator structures. These 12.7 mm bore quadrupoles will have a range of integrated strength from 0.6 to 138 Tesla, with a maximum gradient of 141 Tesla per meter, an adjustment range of +0 to {minus}20% and effective lengths from 324 mm to 972 mm. The magnetic center must remain stable to within 1 micron during the 20% adjustment. In an effort to reduce costs and increase reliability, several designs using hybrid permanent magnets have been developed. Four different prototypes have been built. All magnets have iron poles and use Samarium Cobalt to provide the magnetic fields. Two use rotating permanent magnetic material to vary the gradient, one uses a sliding shunt to vary the gradient and the fourth uses counter rotating magnets. Preliminary data on gradient strength, temperature stability, and magnetic center position stability are presented. These data are compared to an equivalent electromagnetic prototype.
Date:
June 22, 2001
Creator:
al., James T. Volk et
Object Type:
Article
System:
The UNT Digital Library
ADTF SUPERCONDUCTING LINAC DESIGN
None
Date:
June 1, 2001
Creator:
GARNETT, R. W.
Object Type:
Article
System:
The UNT Digital Library
Advanced High Resolution Seismic Imaging, Material Properties Estimation and Full Wavefield Inversion for the Shallow Subsurface
Develop and test advanced near vertical to wide-angle seismic methods for structural imaging and material properties estimation of the shallow subsurface for environmental characterization efforts.
Date:
June 14, 2001
Creator:
Levander, A.; Zelt, C. A. & Symes, W. W.
Object Type:
Report
System:
The UNT Digital Library
The Age, Volume 24, Number 6, June 2001
Monthly publication containing information related to Chambers County, Texas, including current events of the Chambers County Historical Commission, the Wallisville Heritage Park, and the Chambers County historical and genealogical societies; reprinted newspaper articles about county events and citizens; and historical news and records.
Date:
June 2001
Creator:
Wallisville Heritage Park (Organization)
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History
Agent-based modeling of complex infrastructures
Complex Adaptive Systems (CAS) can be applied to investigate complex infrastructures and infrastructure interdependencies. The CAS model agents within the Spot Market Agent Research Tool (SMART) and Flexible Agent Simulation Toolkit (FAST) allow investigation of the electric power infrastructure, the natural gas infrastructure and their interdependencies.
Date:
June 2001
Creator:
North, M. J.
Object Type:
Article
System:
The UNT Digital Library
AHF BEAMS TRANSPORT LATTICE CRYOSYSTEMS[Advanced Hydrotest Facility]
None
Date:
June 1, 2001
Creator:
KELLEY, J. P. & MULHOLLAND, G. T.
Object Type:
Article
System:
The UNT Digital Library
AHF MAGNETIC LENS CRYOSYSTEMS[Advanced Hydrotest Facility]
None
Date:
June 1, 2001
Creator:
KELLEY, J. P. & MULHOLLAND, G. T.
Object Type:
Article
System:
The UNT Digital Library
Air Force Inventory: Parts Shortages Are Impacting Operations and Maintenance Effectiveness
A letter report issued by the General Accounting Office with an abstract that begins "Spare parts shortages on the three Air Force systems GAO reviewed have undermined the performance of assigned missions and the economy and efficiency of maintenance activities. Specifically, the Air Force did not meet its mission-capable goals for the E-3 or C-5 aircrafts during fiscal years 1996-2000, nor did it have enough F-100-220 engines to meet peacetime and wartime goals during that period. These shortages may also affect personnel retention. GAO recently reported that the lack of parts and materials to successfully complete daily job requirements was one of six major factors causing job dissatisfaction among military personnel. Item managers at the maintenance facilities often indicated that spare parts shortages were caused by the inventory management system underestimating the need for spare parts and by delays in the Air Force's repair process as a result of the consolidation of repair facilities. Other reasons included difficulties with producing or repairing parts, reliability of spare parts, and contracting issues. The Air Force and the Defense Logistics Agency have planned or begun many initiatives to alleviate shortages of the spare parts for the three systems GAO reviewed."
Date:
June 27, 2001
Creator:
United States. General Accounting Office.
Object Type:
Report
System:
The UNT Digital Library
Air Quality Forecasting: A Review of Federal Programs and Research Needs
This report provides a brief overview of the state of science of air quality forecasting. The report was composed to guide future federal research in air quality forecasting.
Date:
June 2001
Creator:
National Science and Technology Council (U.S.). Air Quality Research Subcommittee.
Object Type:
Text
System:
The UNT Digital Library
The Alabama School Prayer Case: Chandler v. Siegelman
This report considers the events of Chandler v. James in 1997. The case was a federal district court ruling in Alabama holding up a statute to violate the establishment of religion of the First amendment. The Governor attempted to appeal the court's position to both the Supreme Court and the circuit court but was denied.
Date:
June 25, 2001
Creator:
Ackerman, David M.
Object Type:
Report
System:
The UNT Digital Library
The Albany News (Albany, Tex.), Vol. 126, No. 2, Ed. 1 Thursday, June 7, 2001
Weekly newspaper from Albany, Texas that includes local, county, and state news along with extensive advertising.
Date:
June 7, 2001
Creator:
Lucas, Melinda L.
Object Type:
Newspaper
System:
The Portal to Texas History
The Albany News (Albany, Tex.), Vol. [126], No. [3], Ed. 1 Thursday, June 14, 2001
Weekly newspaper from Albany, Texas that includes local, county, and state news along with extensive advertising.
Date:
June 14, 2001
Creator:
Lucas, Melinda L.
Object Type:
Newspaper
System:
The Portal to Texas History