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1-10 Mbar Laser-Driven Shocks Using the Janus Laser Facility (open access)

1-10 Mbar Laser-Driven Shocks Using the Janus Laser Facility

We report preliminary results using the Lawrence Livermore National Laboratory (LLNL) Janus laser facility to generate high pressure laser-driven shocks in the 1-10 Mbar regime. These experiments address various issues, including shock steadiness, planarity, uniformity and low target preheat, important for making precision EOS measurements on a small (E < 250 J) laser facility. A brief description of the experimental techniques, target design and measurements will be given.
Date: August 10, 2001
Creator: Dunn, J.; Price, D. F.; Moon, S. J.; Cauble, R. C.; Springer, P. T. & Ng, A.
System: The UNT Digital Library
A 1 MEGAWATT POLYPHASE BOOST CONVERTER-MODULATOR FOR KLYSTRON PULSE APPLICATION (open access)

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.
System: The UNT Digital Library
The 2.6 Angstrom resolution structure of Rhodobacter capsulatus bacterioferritin with metal-free dinuclear site and heme iron in a crystallographic 'special position' (open access)

The 2.6 Angstrom resolution structure of Rhodobacter capsulatus bacterioferritin with metal-free dinuclear site and heme iron in a crystallographic 'special position'

None
Date: October 31, 2001
Creator: Cobessi, D.; Huang, L.-S.; Ban, M.; Pon, N. G.; Daldal, F. & Berry, E. A.
System: The UNT Digital Library
2-D Simulations of Drainage Winds and Diffusion Compared to Observations (open access)

2-D Simulations of Drainage Winds and Diffusion Compared to Observations

A vertically integrated dynamical drainage flow model is developed from conservation equations for momentum and mass in a terrain-following coordinate system. Wind fields from the dynamical model drive a Monte Carlo transport and diffusion model. The model needs only topographic data, an Eulerian or Lagrangian time scale and a surface drag coefficient for input data, and can be started with a motionless atmosphere. Model wind and diffusion predictions are compared to observations from the rugged Geysers CA area. Model winds generally agree with observed surface winds, and in some cases may give better estimates of area-averaged flow than point observations. Tracer gas concentration contours agree qualitatively with observed contours, and point predictions of maximum concentrations were correctly predicted to within factors of 2 to 10. Standard statistical tests of model skill showed that the accuracy of the predictions varied significantly from canyon to canyon in the Geysers are a. Model wind predictions are also compared to observations from the Savannah River Plant of SC which has gently rolling terrain. The model correctly simulated the slower development of drainage winds and slower deepening of the drainage layer in the Savannah River Valley, relative to the Geysers CA simulations. The SC simulations …
Date: May 29, 2001
Creator: Garrett, A. J.
System: The UNT Digital Library
10 (micro)m and 5 (micro)m Pinhole-Assisted Point-Projection Backlit Imaging for NIF (open access)

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.
System: The UNT Digital Library
N-15 SIGNALS OF NITROGEN SOURCE AND FATE IN A SEMI-ARID WETLANDS (open access)

N-15 SIGNALS OF NITROGEN SOURCE AND FATE IN A SEMI-ARID WETLANDS

None
Date: August 1, 2001
Creator: Heikoop, J. M. & Hickmott, D. D.
System: The UNT Digital Library
30 years of high-intensity negative ion sources for accelerators (open access)

30 years of high-intensity negative ion sources for accelerators

Thirty years ago, July 1, 1971, significant enhancement of negative ion emission from a gas discharge following an admixture of cesium was observed for the first time. This observation became the basis for the development of Surface Plasma Sources (SPS) for efficient production of negative ions from the interaction of plasma particles with electrodes on which adsorbed cesium reduced the surface work-function. The emission current density of negative ions increased rapidly from j {approximately} 10 mA/cm{sup 2} to 3.7 A/cm{sup 2} with a flat cathode and up to 8 A/cm{sup 2} with an optimized geometrical focusing in the long pulse SPS, and to 0.3 A/cm{sup 2} for DC SPS, recently increased up to 0.7 A/cm{sup 2}. Discovery of charge-exchange cooling helped decrease the negative ion temperature T below 1 eV, and increase brightness by many orders to a level compatible with the best proton sources, B = j/T> 1 A/cm{sup 2} eV. The combination of the SPS with charge-exchange injection improved large accelerators operation and has permitted beam accumulation up to space-charge limit and overcome this limit several times. The early SPS for accelerators have been in operation without modification for {approximately} 25 years. Advanced version of the SPS for …
Date: July 25, 2001
Creator: Dudnikov, Vadim
System: The UNT Digital Library
62-TeV center of mass hadron collider with capability for super bunch beams (open access)

62-TeV center of mass hadron collider with capability for super bunch beams

A 60 TeV center of mass hadron collider is proposed, which has capability of using Superbunch beam. With Superbunch beam, the luminosity is expected to be increased by a factor of 20, compared with conventional acceleration using RF cavities. This hadron collider will be built in two stages with a low field magnet ring first and a high field magnet ring later in the same tunnel. The low field magnet rig will be built with Pipetron scheme, with 7 TeV and 7 TeV proton beams, making a 14 TeV center of mass energy high luminosity collider, using Superbunch beams. In the second stage 10 Tesla high field magnets with twin beams, will be installed. It also utilizes Superbunch beams, realizing high luminosity collider. To accelerate Superbunch beams, the barrier bucket and acceleration induction cells will be used, which are made of induction cells, utilizing FINEMET material. The core loss of the FINEMET is estimated for the whole collider is estimated. The synchrotron radiation of the collider is also estimated. Merits of Superbunch beams over RF bunched beams for the high energy experiments is described.
Date: August 22, 2001
Creator: Takayama, Ryuji Yamada and Ken
System: The UNT Digital Library
62-TeV center of mass hadron collider with superbunch beams (open access)

62-TeV center of mass hadron collider with superbunch beams

The scheme of a 62-TeV center of mass p-p collider with superbunch beams at Fermilab is proposed as a practical and realistically achievable future project. It will be built in two stages, using the same tunnel, first with a 2 Tesla low field magnet collider ring and later with a 10 Tesla high field magnet collider ring. Both low and high field magnets have twin bore aperture and will be installed in the tunnel with the circumference of 87.25 km. In each bore a proton beam is accelerated, using induction cavities to increase luminosity. In the first stage they install a 7 TeV accelerator ring with operating field of 2 Tesla, based on the superferric transmission-line design. This ring will be operated at a 14-TeV center of mass collider. This will have the same energy as the LHC, but it will have 15 times higher luminosity, namely 1.5 x 10{sup 35}/cm{sup 2}/sec. The estimated synchrotron radiation is negligible with this machine. The existing Fermilab accelerator system, including the 150 GeV main injector, will be used as the injector system. Its rough cost estimation and schedule for this first stage are presented. In the second stage proton beams are accelerated, also …
Date: November 5, 2001
Creator: al., Ryuji Yamada et
System: The UNT Digital Library
A 75-keV, 145-mA PROTON INJECTOR (open access)

A 75-keV, 145-mA PROTON INJECTOR

None
Date: July 1, 2001
Creator: Sherman, J. D.; Figueroa, T. L. & Al, Et
System: The UNT Digital Library
80 HP PLASMA ASSISTED CATALYST SYSTEM (open access)

80 HP PLASMA ASSISTED CATALYST SYSTEM

The US economy is linked to efficient heavy vehicle transportation and diesel remains the fuel of choice for mass transportation of goods and services. Diesel engines remain the most reliable and cost effective system for commerce. Recent deleterious effects of diesel exhaust on health and environment have led to an urgent need for cost effective technologies that would bring about reduction in NOx and PM. CARB estimates on-road diesel mobile source will contribute almost 50% NOx and 78% PM emissions by 2010. As a result recent Federal and State mandates have been adopted to reduce emissions from diesel exhaust to 1 Gm/bhp.-Hr of NOx and 0.05 Gm/bhp-hr of PM by the year 2007. The 2007 standard is to be achieved in a stepwise manner starting with the standards for 2002 namely 2 Gm/bhp-hr NOx and 0.1 Gm/bhp-hr of PM. 2002 standards are likely to be met by most engine manufacturer by some modified form of exhaust gas recirculation (EGR) system or by employing a sophisticated engine control system. Importance of cost effective technology requirement is further exaggerated by the fact that in recent years diesel engine production have increased dramatically see figure 1 and has out stripped the gasoline engine …
Date: August 5, 2001
Creator: Slone, Ralph
System: The UNT Digital Library
12th International Workshop on Plant Membrane Biology (open access)

12th International Workshop on Plant Membrane Biology

This report is on 12th International Workshop on Plant Membrane Biology
Date: August 11, 2001
Creator: Spalding, Edgar P.
System: The UNT Digital Library
18th IAEA Fusion Energy Conference Summary of Technology and Power Plans (open access)

18th IAEA Fusion Energy Conference Summary of Technology and Power Plans

There were 90 papers presented at the Conference in the category of Technology and Power Plants accounting for about 25% of the total number of contributions. As was the case at the previous meeting, a large number of papers dealt with the ITER-Engineering Design Activity (EDA) and ITER technology R&D. In the author's opinion, the rapid progress made during the ITER EDA extension on the completion of the new ITER-FEAT design and its physics and technology R&D validation stands out as the highlight of the meeting. Steady progress is being made on several other technology fronts as well. The results point towards emerging research trends in the following areas: steady-state operation with advanced performance and the increasingly important role of enabling technologies in achieving this goal, advanced, high-performance, environmentally attractive materials for the fusion energy goal, reactor and near-term applications studies that exploit advances both in the physics and technology fronts for lower cost of electricity and improved safety and environmental features, and socioeconomic studies that are helping to promote the attractive features of fusion and its public acceptance. The remaining sections of this paper are organized along the lines of these major themes; namely, ITER EDA Design, ITER Technology …
Date: March 9, 2001
Creator: Milora, S. L.
System: The UNT Digital Library
2001 Gordon Research Conference on Laser Diagnostics in Combustion. Final Progress Report (open access)

2001 Gordon Research Conference on Laser Diagnostics in Combustion. Final Progress Report

None
Date: July 6, 2001
Creator: unknown
System: The UNT Digital Library
2001 Gordon Research Conference on Mammalian DNA Repair. Final progress report (open access)

2001 Gordon Research Conference on Mammalian DNA Repair. Final progress report

None
Date: January 26, 2001
Creator: unknown
System: The UNT Digital Library
2001 Gordon Research Conference on Microbial Population Biology. Final progress report (open access)

2001 Gordon Research Conference on Microbial Population Biology. Final progress report

None
Date: August 3, 2001
Creator: Chao, Lin
System: The UNT Digital Library
2001 Gordon Research Conference on MYOGENESIS (open access)

2001 Gordon Research Conference on MYOGENESIS

The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.
Date: May 4, 2001
Creator: unknown
System: The UNT Digital Library
2001 Joint ADVISOR/PSAT Vehicle Systems Modeling User's Conference Proceedings (CD) (open access)

2001 Joint ADVISOR/PSAT Vehicle Systems Modeling User's Conference Proceedings (CD)

The 2001 Joint ADVISOR/PSAT Vehicle Systems Modeling User Conference provided an opportunity for engineers in the automotive industry and the research environment to share their experiences in vehicle systems modeling using ADVISOR and PSAT. ADVISOR and PSAT are vehicle systems modeling tools developed and supported by the National Renewable Energy Laboratory and Argonne National Laboratory respectively with the financial support of the US Department of Energy. During this conference peers presented the results of studies using the simulation tools and improvements that they have made or would like to see in the simulation tools. Focus areas of the presentations included Control Strategy, Model Validation, Optimization and Co-Simulation, Model Development, Applications, and Fuel Cell Vehicle Systems Analysis. Attendees were offered the opportunity to give feedback on future model development plans.
Date: August 1, 2001
Creator: Markel, T.
System: The UNT Digital Library
2nd Feasibility Study of a Muon Storage Ring Neutrino Factory (open access)

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.
System: The UNT Digital Library
3DIVS: 3-Dimensional Immersive Virtual Sculpting (open access)

3DIVS: 3-Dimensional Immersive Virtual Sculpting

Virtual Environments (VEs) have the potential to revolutionize traditional product design by enabling the transition from conventional CAD to fully digital product development. The presented prototype system targets closing the ''digital gap'' as introduced by the need for physical models such as clay models or mockups in the traditional product design and evaluation cycle. We describe a design environment that provides an intuitive human-machine interface for the creation and manipulation of three-dimensional (3D) models in a semi-immersive design space, focusing on ease of use and increased productivity for both designer and CAD engineers.
Date: October 3, 2001
Creator: Kuester, F; Duchaineau, M A; Hamann, B; Joy, K I & Uva, A E
System: The UNT Digital Library
7Li and 31P Magic Angle Spinning Nuclear Magnetic Resonance of LiFePO4-type materials (open access)

7Li and 31P Magic Angle Spinning Nuclear Magnetic Resonance of LiFePO4-type materials

None
Date: November 30, 2001
Creator: Tucker, Michael C.; Doeff, Marca M.; Richardson, Thomas J.; Finones, Rita; Reimer, Jeffrey A. & Cairns, Elton J.
System: The UNT Digital Library
The A dependence of open charm and bottom production (open access)

The A dependence of open charm and bottom production

We study inclusive heavy quark and exclusive heavy quark pair production in pp, pA and AA interactions. Intrinsic transverse momentum is introduced in pp interactions. Nuclear effects, limited to k{sub T} broadening and nuclear shadowing, are introduced in pA and AA interactions. The nuclear dependence is studied over a range of energies, both in fixed target and collider setups.
Date: January 1, 2001
Creator: Vogt, R.
System: The UNT Digital Library
e-A PHYSICS AT A COLLIDER. (open access)

e-A PHYSICS AT A COLLIDER.

An electron-nucleus (e-A) collider with center-of-mass energy in excess of 50 GeV per electron-nucleon collision will allow the physics community to obtain unprecedented new knowledge of the partonic structure of nuclei. If reliable information is to be extracted on these partonic densities, it is essential to realize that with our current level of understanding of QCD, momentum transfers to the struck partons greater than 1 GeV/c are necessary. This requirement puts a priority on high center-of-mass energy if partonic densities are to be measured over a wide range. Comparing the partonic structure of the free nucleon to that of bound nucleons and measuring the systematic changes in that structure as a function of nucleon number (A) will provide deeper insight into the origins and dynamics of nuclear binding. In addition, e-A collisions will allow the exploration of partonic densities appreciably higher than is accessible in e-p collisions. An e-A collider will allow one to measure the gluonic structure functions of nuclei down to x {approx} 10{sup -3}, information valuable in its own right and essential to a quantitative understanding of highly relativistic A-A collisions. The time-space evolution of partons can only be investigated by studying the modifications of hard collisions …
Date: January 9, 2001
Creator: GARVEY, G. T.
System: The UNT Digital Library
Ab initio Calculation of Thermodynamic Data for Oxygenated Hydrocarbon Fuels and Radial Breakdown Species: R(OMe)n (open access)

Ab initio Calculation of Thermodynamic Data for Oxygenated Hydrocarbon Fuels and Radial Breakdown Species: R(OMe)n

There has long been interest in the use of oxygenated hydrocarbon additives to conventional fuels. These oxygenates have been shown to reduce soot emissions in diesel engines and CO emissions in spark-ignition engines; and often allow diesel operation with decreased NO{sub x}. The current widely used additive, MTBE is targeted for elimination as a gasoline additive due to its damaging effects on the environment. This creates a need for alternative oxygenated additives; and more importantly, amplifies the importance to fully understand the thermochemical and kinetic properties on these oxyhydrocarbons fuels and for their intermediate and radical breakdown products. We use CBS-Q and density-functional methods with isodesmic reactions (with group balance when possible) to compute thermodynamic quantities for these species. We have studied hydrocarbons with multiple substituted methoxy groups. In several cases, multioxygenated species are evaluated that may have potential use as new oxygenated fuel additives. Thermodynamic quantities (H{sub 298}{sup 0}, S{sub 298}{sup 0}, C{sub p}(T)) as well as group additivity contributions for the new oxygenated groups are reported. We also report trends in bond-energies with increasing methoxy substitution.
Date: March 23, 2001
Creator: Kubota, A; Pitz, W J; Westbrook, C K; Bozzelli, J & Glaude, P-A
System: The UNT Digital Library