Overview and Status of the Power Conditioning System for the National Ignition Facility (open access)

Overview and Status of the Power Conditioning System for the National Ignition Facility

The National Ignition Facility (NIF) Power Conditioning System (PCS) is a modular capacitive energy storage system that provides over 34 kilojoules of energy to each of the nearly 8000 flashlamps in the NIF laser. Up to 400 megajoules of energy can be stored in the NIF PCS system, discharged through spark gaps and delivered to the flashlamps through a coaxial transmission line system requiring nearly 100 miles of high-voltage cable. The NIF PCS has been under development for nearly 4 years. During this time, the system was developed and designed by Sandia National Laboratory in Albuquerque, NM (SNLA) in conjunction with Lawrence Livermore National Laboratory (LLNL). Extensive reliability testing was performed at SNLA on the First Article NIF Test Module (FANTM) test facility and design improvements were implemented based on FANTM test results, leading to the final design presently undergoing system reliability testing at LLNL. Low-cost energy-storage capacitors, charging power supplies, and reliable, fault-tolerant components were developed through partnerships with numerous contractors. Extensive reliability and fault testing of components has also been performed. This paper will provide an overview of the many efforts that have culminated in the final design of the NIF PCS. The PCS system design will be …
Date: September 11, 2001
Creator: Newton, M A; Fulkerson, E S; Hulsey, S D; Kamm, R E; Pendleton, D L; Petersen, D E et al.
Object Type: Article
System: The UNT Digital Library
Effect of catalyst structure on oxidative dehydrogenation of ethane and propane on alumina-supported vanadia (open access)

Effect of catalyst structure on oxidative dehydrogenation of ethane and propane on alumina-supported vanadia

The catalytic properties of Al2O3-supported vanadia with a wide range of VOx surface density (1.4-34.2 V/nm2) and structure were examined for the oxidative dehydrogenation of ethane and propane. UV-visible and Raman spectra showed that vanadia is dispersed predominantly as isolated monovanadate species below {approx}2.3 V/nm2. As surface densities increase, two-dimensional polyvanadates appear (2.3-7.0 V/nm2) along with increasing amounts of V2O5 crystallites at surface densities above 7.0 V/nm2. The rate constant for oxidative dehydrogenation (k1) and its ratio with alkane and alkene combustion (k2/k1 and k3/k1, respectively) were compared for both alkane reactants as a function of vanadia surface density. Propene formation rates (per V-atom) are {approx}8 times higher than ethene formation rates at a given reaction temperature, but the apparent ODH activation energies (E1) are similar for the two reactants and relatively insensitive to vanadia surface density. Ethene and propene formation rates (per V-atom) are strongly influenced by vanadia surface density and reach a maximum value at intermediate surface densities ({approx}8 V/nm2). The ratio of k2/k1 depends weakly on reaction temperature, indicating that activation energies for alkane combustion and ODH reactions are similar. The ratio of k2/k1 is independent of surface density for ethane, but increase slightly with vanadia surface …
Date: September 11, 2001
Creator: Argyle, Morris D.; Chen, Kaidong; Bell, Alexis T. & Iglesia, Enrique
Object Type: Article
System: The UNT Digital Library
Radiation Tolerance Studies of BTeV Pixel Readout Chip Prototypes (open access)

Radiation Tolerance Studies of BTeV Pixel Readout Chip Prototypes

We report on several irradiation studies performed on BTeV preFPIX2 pixel readout chip prototypes exposed to a 200 MeV proton beam at the Indiana University Cyclotron Facility. The preFPIX2 pixel readout chip has been implemented in standard 0.25 micron CMOS technology following radiation tolerant design rules. The tests confirmed the radiation tolerance of the chip design to proton total dose of 26 MRad. In addition, non destructive radiation-induced single event upsets have been observed in on-chip static registers and the single bit upset cross section has been measured.
Date: September 11, 2001
Creator: al., Gabriele Chiodini et
Object Type: Article
System: The UNT Digital Library
Evaluating DNAPL Source and Migration Zones: M-Area Settling Basin and the Western Sector of A/M Area, Savannah River Site (open access)

Evaluating DNAPL Source and Migration Zones: M-Area Settling Basin and the Western Sector of A/M Area, Savannah River Site

The objective of this investigation is to critically evaluate previous characterization and remediation data to determine the current extent and distribution of DNAPL associated with releases at the M-Area Basin within A/M Area. The primary objective of the effort is to develop an approximate recommendation for the target treatment location and volume near the M Area Settling Basin. Through this analysis the final objective is to identify those subsurface regions having specific geometry and character necessary to cost-effectively deploy DNAPL specific remediation alternatives.
Date: September 11, 2001
Creator: Jackson, D. G.
Object Type: Report
System: The UNT Digital Library
An investigation on {gamma}-U phase stability and thermal compatibility of dispersion fuel meats prepared with atomized U-16at.%Mo,U-14at.%Mo-2at.%Ru and U-14at.%Mo-2at.%Os. (open access)

An investigation on {gamma}-U phase stability and thermal compatibility of dispersion fuel meats prepared with atomized U-16at.%Mo,U-14at.%Mo-2at.%Ru and U-14at.%Mo-2at.%Os.

None
Date: September 11, 2001
Creator: Kim, C. K.; Kim, K. H.; Lee, Y. S.; Park, S. B. & Hofman, G. L.
Object Type: Article
System: The UNT Digital Library
Characterization of Palladium and Ruthenium after Reaction with Tetraphenylborate and Mercury (open access)

Characterization of Palladium and Ruthenium after Reaction with Tetraphenylborate and Mercury

This report documents a second series of X-ray fine structure and chemical analyses to examine the form that Pd - and, to a lesser extent, ruthenium (Ru) - takes in simulated high-level slurries containing TPB salts.
Date: September 11, 2001
Creator: Duff, M.C.
Object Type: Report
System: The UNT Digital Library
Development of a high density pixel multichip module at Fermilab (open access)

Development of a high density pixel multichip module at Fermilab

At Fermilab, a pixel detector multichip module is being developed for the BTeV experiment. The module is composed of three layers. The lowest layer is formed by the readout integrated circuits (ICs). The back of the ICs is in thermal contact with the supporting structure, while the top is flip-chip bump-bonded to the pixel sensor. A low mass flex-circuit interconnect is glued on the top of this assembly, and the readout IC pads are wire-bounded to the circuit. This paper presents recent results on the development of a multichip module prototype and summarizes its performance characteristics.
Date: September 11, 2001
Creator: al., Sergio Zimmermann et
Object Type: Article
System: The UNT Digital Library
Irradiation behavior of uranium-molybdenum dispersion fuel : fuel performance data from RERTR-1 and RERTR-2. (open access)

Irradiation behavior of uranium-molybdenum dispersion fuel : fuel performance data from RERTR-1 and RERTR-2.

None
Date: September 11, 2001
Creator: Meyer, M. K.; Hofman, G. L.; Snelgrove, J. L.; Clark, C. R.; Hayes, S. L.; Strain, R. V. et al.
Object Type: Article
System: The UNT Digital Library
Stable in-reactor performances at low temperature of U-10wt.%Mo dispersion fuel containing centrifugally atomized powder. (open access)

Stable in-reactor performances at low temperature of U-10wt.%Mo dispersion fuel containing centrifugally atomized powder.

None
Date: September 11, 2001
Creator: Kim, K. H.; Park, J. M.; Kim, C. K.; Hofman, G. L.; Meyer, M. K. & Snelgrove, J. L.
Object Type: Article
System: The UNT Digital Library
Smad3 recruits the anaphase-promoting complex for ubiquitination and degradation of SnoN (open access)

Smad3 recruits the anaphase-promoting complex for ubiquitination and degradation of SnoN

Smad proteins mediate transforming growth factor-b signaling to regulate cell growth and differentiation. SnoN is an important negative regulator of TGFb signaling that functions to maintain the repressed state of TGFb target genes in the absence of ligand. Upon TGFb stimulation, Smad3 and Smad2 translocate into the nucleus and induce a rapid degradation of SnoN, allowing activation of TGFb target genes. Here we show that Smad2- or Smad3-induced degradation of SnoN requires the ubiquitin-dependent proteasome and can be mediated by the anaphase promoting complex (APC) and the UbcH5 family of ubiquitin conjugating enzymes. Smad3 and to a lesser extent, Smad2, interact with both the APC and SnoN, resulting in the recruitment of the APC to SnoN and subsequent ubiquitination of SnoN in a destruction box-dependent manner. In addition to the destruction box, efficient degradation of SnoN also requires the Smad3 binding site in SnoN as well as key lysine residues necessary for ubiquitin attachment. Mutation of either the Smad3 binding site or lysine residues results in stabilization of SnoN and in enhanced antagonism of TGFb signaling. Our studies elucidate an important pathway for the degradation of SnoN and reveal a novel role of the APC in regulation of TGFb signaling.
Date: September 11, 2001
Creator: Stroschein, Shannon L.; Bonni, Shirin; Wrana, Jeffrey L. & Luo, Kunxin
Object Type: Article
System: The UNT Digital Library
Electronics for Calorimeters at LHC (open access)

Electronics for Calorimeters at LHC

Some principal design features of front-end electronics for calorimeters in experiments at the LHC will be highlighted. Some concerns arising in the transition from the research and development and design phase to the construction will be discussed. Future challenges will be indicated.
Date: September 11, 2001
Creator: Radeka, V.
Object Type: Article
System: The UNT Digital Library
Influence of Water Addition on Crystalline Silicotitanate Column Operation (open access)

Influence of Water Addition on Crystalline Silicotitanate Column Operation

The proposed use of crystalline silicotitanate (CST) for removal of radiocesium from Savannah River high level waste has received significant research over the past few years. Engineering evaluations of the proposed flow sheet identified several risks. These risks include chemical and thermal stability of the resin, gas generation in the large ion exchange columns, and size reduction and sampling issues for interfacing with the Defense Waste Processing Facility. Research into these potential risks provided information that mitigates or eliminates these risks.
Date: September 11, 2001
Creator: Stallings, M.E.
Object Type: Report
System: The UNT Digital Library
Optically Based Charge Injection System for Ionization Detectors (open access)

Optically Based Charge Injection System for Ionization Detectors

An optically coupled charge injection system for ionization based radiation detectors which allows a test charge to be injected without the creation of ground loops has been developed. An ionization like signal from an external source is brought into the detector through an optical fiber and injected into the electrodes by means of a photodiode. As an application example, crosstalk measurements on a liquid Argon electromagnetic calorimeter readout electrodes were performed.
Date: September 11, 2001
Creator: Chen, H.; Citterio, M.; Lanni, F.; Leite, M. A. L.; Radeka, V.; Rescia, S. et al.
Object Type: Article
System: The UNT Digital Library
Electronics for Calorimeters at LHC (open access)

Electronics for Calorimeters at LHC

Some principal design features of front-end electronics for calorimeters in experiments at the LHC will be highlighted. Some concerns arising in the transition from the research and development and design phase to the construction will be discussed. Future challenges will be indicated.
Date: September 11, 2001
Creator: Radeka, V.
Object Type: Article
System: The UNT Digital Library
Laboratory Evaluation of Base Materials for Neutralization of the Contaminated Aquifer at the F-Area Seepage Basins (open access)

Laboratory Evaluation of Base Materials for Neutralization of the Contaminated Aquifer at the F-Area Seepage Basins

Laboratory studies were performed to support field-testing of base injection into the F-Area Seepage Basins groundwater. The general purpose of these experiments is to provide information to guide the test of base injection and to identify potential adverse effects.
Date: September 11, 2001
Creator: Serkiz, S.M.
Object Type: Report
System: The UNT Digital Library
Effect of ethanol fuel additive on diesel emissions. (open access)

Effect of ethanol fuel additive on diesel emissions.

Engine-out emissions from a Volkswagen model TDI engine were measured for three different fuels: neat diesel fuel, a blend of diesel fuel and additives containing 10% ethanol, and a blend of diesel fuel and additives containing 15% ethanol. The test matrix covered five speeds from 1,320 to 3,000 rpm, five torques from 15 Nm to maximum plus the 900-rpm idle condition, and most of the points in the FTP-75 and US-06 vehicle tests. Emissions of particulate matter (PM), nitrogen oxides (NO{sub x}), unburned hydrocarbons (HCs), and carbon monoxide (CO) were measured at each point, as were fuel consumption, exhaust oxygen, and carbon dioxide output. PM emissions were reduced up to 75% when ethanol-diesel blends were used instead of neat diesel fuel. Significant reductions in PM emissions occurred over one-half to two-thirds of the test matrix. NO{sub x} emissions were reduced by up to 84%. Although the regions of reduced NO{sub x} emissions were much smaller than the regions of reduced PM emissions, there was considerable overlap between the two regions where PM emissions were reduced by up to 75% and NO{sub x} emissions were reduced by up to 84%. Such simultaneous reduction of both PM and NO{sub x} emissions would …
Date: September 11, 2001
Creator: Cole, R. L.; Poola, R. B.; Sekar, R.; Schaus, J. E. & McPartlin, P.
Object Type: Report
System: The UNT Digital Library