Engineering Development of Slurry Bubble Column Reactor (SBCR) Technology (open access)

Engineering Development of Slurry Bubble Column Reactor (SBCR) Technology

This report summarizes the procedures used and results obtained in determining radial gas holdup profiles, via gamma ray scanning, and in assessing liquid and gas mixing parameters, via radioactive liquid and gas tracers, during Fischer Tropsch synthesis. The objectives of the study were (i) to develop a procedure for detection of gas holdup radial profiles in operating reactors and (ii) to test the ability of the developed, previously described, engineering models to predict the observed liquid and gas mixing patterns. It was shown that the current scanning procedures were not precise enough to obtain an accurate estimate of the gas radial holdup profile and an improved protocol for future use was developed. The previously developed physically based model for liquid mixing was adapted to account for liquid withdrawal from the mid section of the column. The ability of our engineering mixing models for liquid and gas phase to predict both liquid and gas phase tracer response was established and illustrated.
Date: July 31, 2002
Creator: Gupta, Puneet
Object Type: Report
System: The UNT Digital Library
Workshop on ENU Mutagenesis: Planning for Saturation, July 25-28, 2002 (open access)

Workshop on ENU Mutagenesis: Planning for Saturation, July 25-28, 2002

The goal of the conference is to enhance the development of improved technologies and new approaches to the identification of genes underlying chemically-induced mutant phenotypes. The conference brings together ENU mutagenesis experts from the United States and aborad for a small, intensive workshop to consider these issues.
Date: July 25, 2002
Creator: Nadeau, Joseph H
Object Type: Article
System: The UNT Digital Library
Enzymatic Upgrading of Heavy Crudes via Partial Oxidation or Conversion of PAHs (open access)

Enzymatic Upgrading of Heavy Crudes via Partial Oxidation or Conversion of PAHs

The objective of this program was to investigate new enzyme-based technologies for upgrading of heavy oils. Enzymes were selected for screening from those capable of conversion of polyaromatic hydrocarbons (PAHs) reported in the literature. Oxidative reactions of PAHs using hydrogen peroxide as an oxidant with conversion to partially oxidized products were used. The enzymes (lignin peroxidase, cytochrome c) were tested in various organic solvents and found to loose activity in pure organic solvents. A thermodynamic analysis revealed lack of effective interaction between the substrate and enzyme as the cause for low activity. The protein cytochrome c was modified to work in organic media by chemical hydrophobic group attachment. Two different modifications were made: attachment of polyethylene glycol (PEG) and alkyl groups. Alkyl groups, being small could be attached at interior locations within the core of the enzyme and possibly near the active site. Increase in the threshold solvent concentration where maximum enzyme activity occurred indicated potential of this strategy for effective enzyme-substrate interaction. Further improvements in enzyme activity called for other diverse methods due to the unavailability of sufficient chemical modification sites. Genetic techniques were therefore explored for further improvements. These experiments focused on cloning of a gene for the …
Date: July 1, 2002
Creator: Borole, A. P.; Davison, B. H. & Kuritz, T.
Object Type: Report
System: The UNT Digital Library
Going with the flow: Life cycle costing for industrial pumping systems (open access)

Going with the flow: Life cycle costing for industrial pumping systems

Industries worldwide depend upon pumping systems for theirdaily operation. These systems account for nearly 20 percent of theworld's industrial electrical energy demand and range from 25-50 percentof the energy usage in certain industrial plant operations. Purchasedecisions for a pump and its related system components are typicallybased upon a low bid, rather than the cost to operate the system over itslifetime. Additionally, plant facilities personnel are typically focussedon maintaining existing pumping system reliability rather than optimizingthe systems for best energy efficiency. To ensure the lowest energy andmaintenance costs, equipment life, and other benefits, the systemcomponents must be carefully matched to each other, and remain sothroughout their working lives. Life Cycle Cost (LCC) analysis is a toolthat can help companies minimize costs and maximize energy efficiency formany types of systems, including pumping systems. Increasing industryawareness of the total cost of pumping system ownership through lifecycle cost analysis is a goal of the US Department of Energy (DOE). Thispaper will discuss what DOE and its industry partners are doing to createthis awareness. A guide book, Pump Life Cycle Costs: A Guide to LCCAnalysis for Pumping Systems, developed by the Hydraulic Institute (HI)and Europump (two pump manufacturer trade associations) with DOEinvolvement, will be overviewed. …
Date: July 8, 2002
Creator: Tutterow, Vestal; Hovstadius, Gunnar & McKane, Aimee
Object Type: Article
System: The UNT Digital Library
A cold mass support system based on the use of oriented fiberglassepoxy rods in bending (open access)

A cold mass support system based on the use of oriented fiberglassepoxy rods in bending

This report describes a cold mass support system based on the use of oriented fiberglassepoxy rods in bending.
Date: July 6, 2002
Creator: Green, Michael A.; Corradi, Carol A.; LaMantia, Roberto F. & Zbasnik, Jon P.
Object Type: Article
System: The UNT Digital Library
One-piece, composite crucible with integral withdrawal/discharge section (open access)

One-piece, composite crucible with integral withdrawal/discharge section

A one-piece, composite open-bottom casting mold with integral withdrawal section is fabricated by thermal spraying of materials compatible with and used for the continuous casting of shaped products of reactive metals and alloys such as, for example, titanium and its alloys or for the gas atomization thereof.
Date: July 30, 2002
Creator: Besser, Matthew; Terpstra, Robert L. (Iowa State Univ., Ames, IA); Sordelet, Daniel J.; Anderson, Iver E.; Hartman, Alan D.; Argetsinger, Edward R. et al.
Object Type: Patent
System: The UNT Digital Library
Hybrid-Electric Transit Buses: NYCT (New York City Transit) Diesel Hybrid-Electric Buses: Final Results (Brochure) (open access)

Hybrid-Electric Transit Buses: NYCT (New York City Transit) Diesel Hybrid-Electric Buses: Final Results (Brochure)

Final results of the New York City Transit Hybrid-Electric Transit Bus Study. Hybrid buses had lower emissions, higher fuel economy, and higher operating costs compared with diesel buses. New York City Transit (NYCT), part of the Metropolitan Transportation Authority in New York, began operating the first of 10 heavy-duty diesel hybrid-electric transit bus prototypes (Model VI) from Orion Bus Industries in 1998. All 10 buses were in revenue service by mid-2000. The hybrid buses are intended to provide NYCT with increased fuel economy and lower levels of harmful exhaust emissions, compared with NYCT's diesel transit buses. Between 1999 and 2001 (over various predefined fuel and maintenance evaluation periods), these first 10 hybrid buses were part of a data collection and analysis project sponsored by the U.S. Department of Energy (DOE). The operating costs, efficiency, emissions, and overall performance of these low-floor hybrid buses were compared against those of 14 conventional high-floor diesel transit buses (7 each from NovaBUS Corporation and Orion) operated by NYCT in similar service. Results indicate that the hybrid buses operate with greater fuel efficiency and much lower emissions, compared with the diesel buses. Maintenance costs for the prototype hybrid buses were significantly higher than those of …
Date: July 1, 2002
Creator: unknown
Object Type: Text
System: The UNT Digital Library
SLURM: Simple Linux Utility for Resource Management (open access)

SLURM: Simple Linux Utility for Resource Management

Simple Linux Utility for Resource Management (SLURM) is an open source, fault-tolerant, and highly scalable cluster management and job scheduling system for Linux clusters of thousands of nodes. Components include machine status, partition management, job management, scheduling and stream copy modules. The design also includes a scalable, general-purpose communication infrastructure. This paper presents a overview of the SLURM architecture and functionality.
Date: July 8, 2002
Creator: Jette, Morris A.; Dunlap, Chris; Garlick, Jim & Grondona, Mark
Object Type: Text
System: The UNT Digital Library
Electrical Isolation of ZnO by Ion Irradiation (open access)

Electrical Isolation of ZnO by Ion Irradiation

We demonstrate the formation of highly resistive single-crystal ZnO epilayers as a result of irradiation with MeV Li, O, and Si ions. Results show that the ion doses necessary for electrical isolation close-to-inversely depend on the number of ion-beam-generated atomic displacements. However, in all the cases studied, defect-induced electrical isolation of ZnO is unstable to rapid thermal annealing at temperatures above about 300 C . No significant improvement of thermal stability is found by varying ion mass, dose, and irradiation temperature (up to 350 C). Finally, a comparison of implant isolation in ZnO with that in GaN is presented.
Date: July 3, 2002
Creator: Kucheyev, S. O.; Jagadish, C.; Williams, J. S.; Deenapanray, P. N. K.; Yano, M.; Koike, K. et al.
Object Type: Article
System: The UNT Digital Library
Low Cost Glass and Glass-Ceramic Substrates for Thin-Film Silicon Solar Cells: Final Subcontract Report, 25 January 2001 (open access)

Low Cost Glass and Glass-Ceramic Substrates for Thin-Film Silicon Solar Cells: Final Subcontract Report, 25 January 2001

This report describes how Cornell University researchers developed several low-cost and simple barrier layers and tested their effectiveness both analytically (by SIMS) and by evaluating the electrical characteristics of devices fabricated on barrier-coated substrates. Devices fabricated included both majority-carrier devices (thin-film transistors) and minority-carrier devices (p-i-n junction diodes simulating solar cells) using various deposition techniques including the chemical vapor deposition of polysilicon from silane at low pressures (at Cornell University) and from dichlorosilane at atmospheric pressure (cooperation with Neudeck at Purdue University). The structure of the films deposited was investigated by using TEM and X-ray analysis. The performance of the minority- and majority-carrier devices fabricated on barrier-coated glass ceramic substrates was found to be identical to devices fabricated on control substrates of oxidized silicon and fused silica.
Date: July 1, 2002
Creator: Ast, D.; Nemchuk, N. & Krasula, S.
Object Type: Report
System: The UNT Digital Library
Free Space Optical Communications Utilizing MEMS Adaptive Optics Correction (open access)

Free Space Optical Communications Utilizing MEMS Adaptive Optics Correction

Free space optical communications (FSO) are beginning to provide attractive alternatives to fiber-based solutions in many situations. Currently, a handful of companies provide fiberless alternatives specifically aimed at corporate intranet and sporting event video applications. These solutions are geared toward solving the ''last mile'' connectivity issues. There exists a potential need to extend this pathlength to distances much greater than a 1 km, particularly for government and military applications. For cases of long distance optical propagation, atmospheric turbulence will ultimately limit the maximum achievable data rate. In this paper, we propose a method to improve signal quality through the use of adaptive optics. In particular, we show work in progress toward a high-speed, small footprint Adaptive Optics system for horizontal and slant path laser communications. Such a system relies heavily on recent progress in Micro-Electro-Mechanical Systems (MEMS) deformable mirrors, as well as improved communication and computational components.
Date: July 9, 2002
Creator: Thompson, C. A.; Kartz, M. W.; Flath, L. M.; Wilks, S. C.; Young, R. A.; Johnson, G. W. et al.
Object Type: Article
System: The UNT Digital Library
Photometric Calibration of an EUV Flat Field Spectrometer at the Advanced Light Source (open access)

Photometric Calibration of an EUV Flat Field Spectrometer at the Advanced Light Source

The photometric calibration of ail extreme ultraviolet flat field spectrometer has been done at the Advanced Light Source at LBNL. This spectrometer is used to record spectrum for atomic physics research from highly charged ions in plasmas created in the Livermore electron beam ion traps EBIT-I and SUPEREBIT. Two calibrations were done each with a different gold-coated grating, a 1200 {ell}/mm and a 2400 {ell}/mm, that covered 75-300{angstrom} and 15-160{angstrom}, respectively. The detector for this calibration was a back thinned CCD. The relative calibration was determined for several different incident angles for both gratings. Within the scatter of the data, the calibration was roughly insensitive to the incidence angle for the range of angles investigated.
Date: July 3, 2002
Creator: May, M.; Lepson, J.; Beiersdorfer, P.; Thorn, D.; Chen, H.; Hey, D. et al.
Object Type: Article
System: The UNT Digital Library
Lifetime of the 1s2p {sup 1}P{sub 1} Excited Level in Fe{sup 24+} (open access)

Lifetime of the 1s2p {sup 1}P{sub 1} Excited Level in Fe{sup 24+}

Measurements of the spectrum of Fe{sup 24+} in the 1.845 {angstrom} to 1.885 {angstrom} range obtained on the EBIT-I electron beam ion trap at Lawrence Livermore National Laboratory were used for determining the radiative lifetime of the ls2p {sup 1}P{sub 1} excited state. The spectrum contains electric dipole forbidden transitions at 1.855{angstrom} (''x'') and 1.868{angstrom} (''z'') whose lineshape is well represented by a Gaussian line profile and is assumed to be due primarily to Doppler and instrumental broadening. The Gaussian contribution is assumed to be the same for all lines in the spectrum. This assumption simplifies the problem when considering a more complex combination of broadening mechanisms. For allowed transitions such as 1s2p {sup 1}P{sub 1} {yields} 1s{sup 2} {sup 1}S{sub 0}, ''w'', at 1.850 {angstrom} we assume a Voigt profile. In the simplest case this combines both natural (Lorentzian) and Doppler (Gaussian) broadening effects which contribute to the width of the spectral line. With the Gaussian contribution determined from lines ''x'' and ''z'', deconvolving the Gaussian from the Voigt profile gives the natural line width. This then is directly related to the radiative lifetime of the 1s2p {sup 1}P{sub 1} excited level.
Date: July 2, 2002
Creator: Beiersdorfer, P; Graf, A; Harris, C L; Hwang, D Q & Neill, P A
Object Type: Article
System: The UNT Digital Library
UNIVERSAL BEHAVIOR OF CHARGED PARTICLE PRODUCTION IN HEAVY ION COLLISIONS. (open access)

UNIVERSAL BEHAVIOR OF CHARGED PARTICLE PRODUCTION IN HEAVY ION COLLISIONS.

The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at {radical}(s{sub NN}) = 19.6, 130 and 200 GeV. Two observations indicate universal behavior of charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/{bar p}p and e{sup +}e{sup -} data. <Nch>/<N{sub part}/2> in nuclear collisions at high energy scales with {radical}s in a similar way as N{sub ch} in e{sup +}e{sup -} collisions and has a very weak centrality dependence. These features may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.
Date: July 24, 2002
Creator: STEINBERG,P. A. FOR THE PHOBOS COLLABORATION
Object Type: Article
System: The UNT Digital Library
Signaling to the P53 Tumor Suppressor Through Pathways Activated by Genotoxic and Non-Genotoxic Stresses. (open access)

Signaling to the P53 Tumor Suppressor Through Pathways Activated by Genotoxic and Non-Genotoxic Stresses.

The p53 tumor suppressor is a tetrameric transcription factor that is post-translational modified at {approx}18 different sites by phosphorylation, acetylation, or sumoylation in response to various cellular stress conditions. Specific posttranslational modifications, or groups of modifications, that result from the activation of different stress-induced signaling pathways are thought to modulate p53 activity to regulate cell fate by inducing cell cycle arrest, apoptosis, or cellular senescence. Here we review the posttranslational modifications to p53 and the pathways that produce them in response to both genotoxic and non-genotoxic stresses.
Date: July 1, 2002
Creator: Anderson, C. W. & Appella, E.
Object Type: Book
System: The UNT Digital Library
Evaluation of the Radiochemistry of Near-Field Water Samples at the Nevada Test Site Applied to the Definition of a Hydrologic Source Term (open access)

Evaluation of the Radiochemistry of Near-Field Water Samples at the Nevada Test Site Applied to the Definition of a Hydrologic Source Term

Effective management of available groundwater resources and strategies for remediation of water impacted by past nuclear testing practices depend on knowledge about the migration of radionuclides in groundwater away from the sites of the explosions. A primary concern is to assess the relative mobilities of the different radionuclide species found near sites of underground nuclear tests and to determine the concentration, extent, and speed of this movement. Ultimately the long term transport behavior of radionuclides with half-lives long enough that they will persist for decades, their interaction with groundwater, and the resulting flux of these contaminants is of paramount importance. As part of a comprehensive approach to these assessments, more than three decades of site-specific sites studies have been undertaken at the Nevada Test Site (NTS) which have focused on the means responsible for the observed or suspected movement of radionuclides away from underground nuclear tests (RNM, 1983). More recently regional and local models of groundwater flow and radionuclide transport have been developed as part of a federal and state of Nevada program to assess the long-term effects of underground nuclear testing on human health and environment (e.g., U.S. DOE/NV, 1997a; Tompson et al., 1999; Pawloski et al., 2001). Necessary …
Date: July 5, 2002
Creator: Smith, D K
Object Type: Report
System: The UNT Digital Library
Review of Excess Weapons Plutonium Disposition LLNL Contract Work in Russia-(English) (open access)

Review of Excess Weapons Plutonium Disposition LLNL Contract Work in Russia-(English)

This third meeting of the recently completed and ongoing Russian plutonium immobilization contract work was held at the State Education Center (SEC) in St. Petersburg on January 14-18, 2002. The meeting agenda is reprinted here as Appendix A and the attendance list as Appendix B. The meeting had 58 Russian participants from 21 Russian organizations, including the industrial sites (Mayak, Krasonayarsk-26, Tomsk), scientific institutes (VNIINM, KRI, VNIPIPT, RIAR), design organizations (VNIPIET and GSPI), universities (Nyzhny Novgorod, Urals Technical), Russian Academy of Sciences (Institute of Physical Chemistry or IPhCh, Institute of Ore-Deposit Geology, Petrography, Mineralogy, and Geochemistry or IGEM), Radon-Moscow, S&TC Podol'osk, Kharkov-Ukraine, GAN-SEC-NRS and SNIIChM, the RF Ministry of Atomic Energy (Minatom) and Gosatomnadzor (GAN). This volume, published by LLNL, documents this third annual meeting. Forty-nine technical papers were presented by the Russian participants, and nearly all of these have been collected in this Proceedings. The two objectives for the meeting were to: (1) Bring together the Russian organizations, experts, and managers performing this contract work into one place for four days to review and discuss their work amongst each other. (2) Publish a meeting summary and proceedings of all the excellent Russian plutonium immobilization and other plutonium disposition contract …
Date: July 11, 2002
Creator: Jardine, L & Borisov, G B
Object Type: Report
System: The UNT Digital Library
DC surface-plasma source with high emission current density. (open access)

DC surface-plasma source with high emission current density.

None
Date: July 1, 2002
Creator: Dudnikov, V.; Schmidt, C.W.; Hren, R. & Wendt, J.
Object Type: Article
System: The UNT Digital Library
High-nitrogen explosives (open access)

High-nitrogen explosives

The syntheses and characterization of various tetrazine and furazan compounds offer a different approach to explosives development. Traditional explosives - such as TNT or RDX - rely on the oxidation of the carbon and hydrogen atoms by the oxygen carrying nitro group to produce the explosive energy. High-nitrogen compounds rely instead on large positive heats of formation for that energy. Some of these high-nitrogen compounds have been shown to be less sensitive to initiation (e.g. by impact) when compared to traditional nitro-containing explosives of similar performances. Using the precursor, 3,6-bis-(3,5-dimethylpyrazol-1-yl)-s-tetrazine (BDT), several useful energetic compounds based on the s-tetrazine system have been synthesized and studied. The compound, 3,3{prime}-azobis(6-amino-s-tetrazine) or DAAT, detonates as a half inch rate stick despite having no oxygen in the molecule. Using perfluoroacetic acid, DAAT can be oxidized to give mixtures of N-oxide isomers (DAAT03.5) with an average oxygen content of about 3.5. This energetic mixture burns at extremely high rates and with low dependency on pressure. Another tetrazine compound of interest is 3,6-diguanidino-s-tetrazine(DGT) and its dinitrate and diperchlorate salts. DGT is easily synthesized by reacting BDT with guanidine in methanol. Using Caro's acid, DGT can be further oxidized to give 3,6-diguanidino-s-tetrazine-1,4-di-N-oxide (DGT-DO). Like DGT, the di-N-oxide …
Date: July 2002
Creator: Naud, Darren; Hiskey, Michael A.; Kramer, John F.; Bishop, Robert L.; Harry, Herbert H.; Son, Steven F. et al.
Object Type: Article
System: The UNT Digital Library
Root engineering for self-irrigation that exploits soil depth dimension for carbon sequestration. (open access)

Root engineering for self-irrigation that exploits soil depth dimension for carbon sequestration.

A comprehensive carbon management program to sequester excess CO{sub 2} includes the maximization of the carbon sink potential of the terrestrial ecosystem. The establishment of sustainable vegetation on semi-arid or damaged land is necessary to increase the carbon inventory in the terrestrial ecosystem, as it is increasing the depth of the soil carbon sink. The availability of water for sustained growth at acceptable costs, when or where precipitation is too scarce or unpredictable, may, however, significantly affect the cost and sustainability of the revegetation efforts. We tested an innovative technology that enables the establishment of 'plantations' that are independent of erratic water supplies or irrigation by developing deep root systems that tap into deeper groundwater. Applied Natural Sciences (ANS) patented technologies (TreeMediation{reg_sign} and TreeWell{reg_sign} systems) overcome soil conditions unfavorable to deep rooting and 'engineer' the growth of phreatophytic tree roots into soil to reliably reach the groundwater. Carbon sinks can then be increased by increasing rooting depths and especially by enabling vegetative growth altogether. We collected soil cores from three phytoremediation sites where these technologies have been previously deployed. From these, we developed detailed information on root density and soil conditions at increasing depths to estimate C gains. The largest …
Date: July 16, 2002
Creator: Gatliff, E. G. & Negri, M. C.
Object Type: Report
System: The UNT Digital Library
The Nez Perce Tribe's Enhanced Conservation Enforcement for Fish, Wildlife, and Watersheds of the Nez Perce; Monitoring and Evaluation, 2001-2002 Annual Report. (open access)
Area Monitoring Dosimeter Program for the Pacific Northwest National Laboratory: Results for CY 2001 (open access)

Area Monitoring Dosimeter Program for the Pacific Northwest National Laboratory: Results for CY 2001

Pacific Northwest National Laboratory (PNNL) established an area monitoring dosimeter program in accordance with Article 514 of the U.S. Department of Energy (DOE) Radiological Control Manual (RCM) in January 1993. This program is to minimize the number of areas requiring issuance of personnel dosimeters and to demonstrate that doses outside Radiological Buffer Areas are negligible. In accordance with 10 CFR Part 835.402 (a) (1)-(4) and Article 511.1 of the PNNL Radiological Control Program Description, personnel dosimetry shall be provided to 1) radiological workers who are likely to receive at least 100 mrem annually, and 2) declared pregnant workers, minors, and members of the public who are likely to receive at least 50 mrem annually. Program results for calendar years 1993-2001 confirm that personnel dosimetry is not needed for individuals located in areas monitored by the program.
Date: July 8, 2002
Creator: Bivins, Steven R. & Stoetzel, Gregory A.
Object Type: Report
System: The UNT Digital Library
HPVB and HPVZM Shaped Growth of CdZnTe, CdSe and ZnSe Crystals. (open access)

HPVB and HPVZM Shaped Growth of CdZnTe, CdSe and ZnSe Crystals.

None
Date: July 7, 2002
Creator: Kolesnikov, N. N.; James, R. B.; Berzigiarova, N. S. & Kulakov, M. P.
Object Type: Article
System: The UNT Digital Library
AGS Circumference Change when Pulsing 3/2 Lamdba G10 Bump (open access)

AGS Circumference Change when Pulsing 3/2 Lamdba G10 Bump

N/A
Date: July 1, 2002
Creator: W., Glenn J. & Harvey, M.
Object Type: Report
System: The UNT Digital Library