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
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
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.
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.
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.
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.
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
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
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.
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.
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.
System: The UNT Digital Library
Performing Trade Studies in the CERCLA Environment (open access)

Performing Trade Studies in the CERCLA Environment

During almost any project, situations will arise that require project management and/or engineering personnel to make choices regarding project direction or product development. Often these choices are simply a part of the normal engineering development cycle (e.g., refinement or optimization of the product design). Frequently, on Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and other similar projects, trade studies are initiated to address concerns or issues raised by stakeholders (e.g., EPA, local and state governments, local tribes, public). Where CERCLA projects, by definition, deal with releases or threatened releases of hazardous substances that may endanger public health or the environment, these trade studies must balance safety, risk and health issues, as well as cost and engineering viability. How these trade studies are carried out and documented/presented to the stakeholders involved can often be the difference between continued project progress and a "stalemate" leaving the project in limbo. This document describes a basic trade study process, which has proved successful in addressing stakeholder concerns while at the same time balancing the desires of the various parties involved.
Date: July 1, 2002
Creator: Borland, Mark Wilson; Rice, Philip Matthew & Jamison, Ronald Kirt
System: The UNT Digital Library
Overview of the SuperNova/Acceleration probe (SNAP) (open access)

Overview of the SuperNova/Acceleration probe (SNAP)

The SuperNova/Acceleration Probe (SNAP) is a space-based experiment to measure the expansion history of the Universe and study both its dark energy and the dark matter. The experiment is motivated by the startling discovery that the expansion of the Universe is accelerating. A 0.7 square-degree imager comprised of 36 large format fully-depleted n-type CCD's sharing a focal plane with 36 HgCdTe detectors forms the heart of SNAP, allowing discovery and lightcurve measurements simultaneously for many supernovae. The imager and a high-efficiency low-resolution integral field spectrograph are coupled to a 2-m three mirror anastigmat wide-field telescope, which will be placed in a high-earth orbit. The SNAP mission can obtain high-signal-to-noise calibrated light-curves and spectra for over 2000 Type Ia supernovae at redshifts between z = 0.1 and 1.7. The resulting data set can not only determine the amount of dark energy with high precision, but test the nature of the dark energy by examining its equation of state. In particular, dark energy due to a cosmological constant can be differentiated from alternatives such as ''quintessence'', by measuring the dark energy's equation of state to an accuracy of {+-} 0.05, and by studying its time dependence.
Date: July 29, 2002
Creator: galdering@lbl.gov
System: The UNT Digital Library
SNAP Telescope (open access)

SNAP Telescope

The SuperNova/Acceleration Probe (SNAP) mission will require a two-meter class telescope delivering diffraction limited images spanning a one degree field in the visible and near infrared wavelength regime. This requirement, equivalent to nearly one billion pixel resolution, places stringent demands on its optical system in terms of field flatness, image quality, and freedom from chromatic aberration. We discuss the advantages of annular-field three-mirror anastigmat (TMA) telescopes for applications such as SNAP, and describe the features of the specific optical configuration that we have baselined for the SNAP mission. We discuss the mechanical design and choice of materials for the telescope. Then we present detailed ray traces and diffraction calculations for our baseline optical design. We briefly discuss stray light and tolerance issues, and present a preliminary wavefront error budget for the SNAP Telescope. We conclude by describing some of tasks to be carried out during the upcoming SNAP research and development phase.
Date: July 29, 2002
Creator: Lampton, Michael L.; Akerlof, C. W.; Aldering, G.; Amanullah, R.; Astier, P.; Barrelet, E. et al.
System: The UNT Digital Library
Wide-field surveys from the SNAP mission (open access)

Wide-field surveys from the SNAP mission

The Supernova/Acceleration Probe (SNAP) is a proposed space-borne observatory that will survey the sky with a wide-field optical/NIR imager. The images produced by SNAP will have an unprecedented combination of depth, solid-angle, angular resolution, and temporal sampling. Two 7.5 square-degree fields will be observed every four days over 16 months to a magnitude depth of AB = 27.7 in each of nine filters. Co-adding images over all epochs will give an AB = 30.3 per filter. A 300 square-degree field will be surveyed with no repeat visits to AB = 28 per filter. The nine filters span 3500-17000 {angstrom}. Although the survey strategy is tailored for supernova and weak gravitational lensing observations, the resulting data supports a broad range of auxiliary science programs.
Date: July 23, 2002
Creator: agkim@lbl.gov
System: The UNT Digital Library
Rates and technologies for mass-market demand response (open access)

Rates and technologies for mass-market demand response

Demand response programs are often quickly and poorlycrafted in reaction to an energy crisis and disappear once the crisissubsides, ensuring that the electricity system will be unprepared whenthe next crisis hits. In this paper, we propose to eliminate theevent-driven nature of demand response programs by considering demandresponsiveness a component of the utility obligation to serve. As such,demand response can be required as a condition of service, and theoffering of demand response rates becomes a requirement of utilities asan element of customer service. Using this foundation, we explore thecosts and benefits of a smart thermostat-based demand response systemcapable of two types of programs: (1) a mandatory, system-operatorcontrolled, contingency program, and (2) a voluntary, customercontrolled, bill management program with rate-based incentives. Anydemand response program based on this system could consist of either orboth of these components. Ideally, these programs would be bundled,providing automatic load management through customer-programmed priceresponse, plus up to 10 GW of emergency load shedding capability inCalifornia. Finally, we discuss options for and barriers toimplementation of such a program in California.
Date: July 21, 2002
Creator: Herter, Karen; Levy, Roger; Wilson, John & Rosenfeld, Arthur
System: The UNT Digital Library
Understanding bottom production (open access)

Understanding bottom production

We describe calculations of b overline b production tonext-to-next-to-leadi ng order (NNLO) and next-to-next-to-leadinglogarithm (NNLL) near threshold in pp interactions. Our calculations arein good agreement with the b overline b total cross section measured byHERA-B.
Date: July 31, 2002
Creator: Kidonakis, N.; Laenen, E.; Moch, S. & Vogt, R.
System: The UNT Digital Library
Magnetic gradiometer based on a high-transition temperature superconducting quantum interference device for improved sensitivity of abiosensor (open access)

Magnetic gradiometer based on a high-transition temperature superconducting quantum interference device for improved sensitivity of abiosensor

We describe a gradiometer based on a high-transition temperature Superconducting Quantum Interference Device (SQUID) for improving the sensitivity of a SQUID-based biosensor. The first-derivative gradiometer, fabricated from a single layer of YBa{sub 2}Cu{sub 3}O{sub 7-x}, has a baseline of 480 {micro}m and a balance against uniform fields of 1 part in 150. Used in our SQUID ''microscope,'' it reduces parasitic magnetic fields generated by the measurement process to the level of the SQUID noise. The gradiometer-based microscope is two orders of magnitude more sensitive to super paramagnetic nanoparticles bound to biological targets than our earlier magnetometer-based microscope.
Date: July 8, 2002
Creator: Lee, Seung Kyun; Myers, W. R.; Grossman, H. L.; Cho, H.-M.; Chemla,Y. R. & Clarke, John
System: The UNT Digital Library
Crosswell seismic and electromagnetic monitoring of CO2sequestration (open access)

Crosswell seismic and electromagnetic monitoring of CO2sequestration

The quantitative estimation of changes in water saturation (S{sub W}) and effective pressure (P), in terms of changes in compressional and shear impedance, is becoming routine in the interpretations of time-lapse surface seismic data. However, when the number of reservoir constituents increases to include in situ gas and injected CO{sub 2}, there are too many parameters to be determined from seismic velocities or impedances alone. In such situations, the incorporation of electromagnetic (EM) images showing the change in electrical conductivity ({sigma}) provides essential independent information. The purpose of this study was to demonstrate a methodology for jointly interpreting crosswell seismic and EM data, in conjunction with detailed constitutive relations between geophysical and reservoir parameters, to quantitatively predict changes in P, S{sub W}, CO{sub 2} gas saturation (S{sub CO2}), CO{sub 2} gas/oil ratio (R{sub CO{sub 2}}), hydrocarbon gas saturation (S{sub g}), and hydrocarbon gas/oil ration (R{sub g}) in a reservoir undergoing CO{sub 2} flood.
Date: July 30, 2002
Creator: Hoversten, G. Michael; Gritto, Roland; Daley, Thomas M.; Majer,Ernest L. & Myer, Larry R.
System: The UNT Digital Library
Molecular Basis of Microbial One-Carbon Metabolism (open access)

Molecular Basis of Microbial One-Carbon Metabolism

The Gordon Research Conference (GRC) on Molecular Basis of Microbial One-Carbon Metabolism was held at Connecticut College, New London, Connecticut. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.
Date: July 12, 2002
Creator: unknown
System: The UNT Digital Library
Proton radiation damage in P-channel CCDs fabricated on high-resistivity silicon (open access)

Proton radiation damage in P-channel CCDs fabricated on high-resistivity silicon

P-channel, backside illuminated silicon CCDs were developed and fabricated on high-resistivity n-type silicon. Devices have been exposed up to 1x1011 protons/cm2 at 12 MeV. The charge transfer efficiency and dark current were measured as a function of radiation dose. These CCDs were found to be significantly more radiation tolerant than conventional n-channel devices. This could prove to be a major benefit for long duration space missions.
Date: July 28, 2002
Creator: Bebek, C.; Groom, D.; Holland, S.; Karcher, A.; Kolbe, W.; Lee, J. et al.
System: The UNT Digital Library
Integrated X-ray and charged particle active pixel CMOS sensor arrays using an epitaxial silicon sensitive region (open access)

Integrated X-ray and charged particle active pixel CMOS sensor arrays using an epitaxial silicon sensitive region

Integrated CMOS Active Pixel Sensor (APS) arrays have been fabricated and tested using X-ray and electron sources. The 128 by 128 pixel arrays, designed in a standard 0.25 micron process, use a {approx}10 micron epitaxial silicon layer as a deep detection region. The epitaxial layer has a much greater thickness than the surface features used by standard CMOS APS, leading to stronger signals and potentially better signal-to-noise ratio (SNR). On the other hand, minority carriers confined within the epitaxial region may diffuse to neighboring pixels, blur images and reduce peak signal intensity. But for low-rate, sparse-event images, centroid analysis of this diffusion may be used to increase position resolution. Careful trade-offs involving pixel size and sense-node area verses capacitance must be made to optimize overall performance. The prototype sensor arrays, therefore, include a range of different pixel designs, including different APS circuits and a range of different epitaxial layer contact structures. The fabricated arrays were tested with 1.5 GeV electrons and Fe-55 X-ray sources, yielding a measured noise of 13 electrons RMS and an SNR for single Fe-55 X-rays of greater than 38.
Date: July 1, 2002
Creator: Kleinfelder, Stuart; Bichsel, Hans; Bieser, Fred; Matis, Howard S.; Rai, Gulshan; Retiere, Fabrice et al.
System: The UNT Digital Library
Elastic stability and the limit of strength (open access)

Elastic stability and the limit of strength

The upper limit of strength (the ''theoretical strength'') has been an active subject of research and speculation for the better part of a century. The subject has recently become important, for two reasons. First, given recent advances in ab initio techniques and computing machines, the limits of strength can be calculated with considerable accuracy, making this one of the very few problems in mechanical behavior that can actually be solved. Second, given recent advances in materials engineering, the limits of strength are being approached in some systems, such as hardened or defect-free films, and their relevance is becoming recognized in others. The present paper discusses some interesting results from recent research on the limits of strength, with an intermixture of speculations based on those results. Topics include the inherent nature of {l_brace}100{r_brace} cleavage and ''pencil slip'' in bcc metals, the inherent ductility of fcc metals, the anomalous properties of Al, and the possibility of measuring ideal strength with nanoindentation.
Date: July 1, 2002
Creator: Morris Jr., J.W.; Krenn, C.R.; Roundy, D. & Cohen, Marvin L.
System: The UNT Digital Library
Atomic & Molecular Interactions (open access)

Atomic & Molecular Interactions

The Gordon Research Conference (GRC) on Atomic & Molecular Interactions was held at Roger Williams University, Bristol, RI. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.
Date: July 12, 2002
Creator: unknown
System: The UNT Digital Library