2005 Quantum Control of Light and Matter - Conference July 31 - August 5, 2005 (open access)

2005 Quantum Control of Light and Matter - Conference July 31 - August 5, 2005

This report is about Quantum Control of Light and Matter Gordon Research Conference
Date: September 11, 2006
Creator: Corkum, Paul B.
Object Type: Article
System: The UNT Digital Library
An Ab Initio Approach Towards Engineering Fischer-Tropsch Surface Chemistry (open access)

An Ab Initio Approach Towards Engineering Fischer-Tropsch Surface Chemistry

As the US seeks to develop an energy strategy that reduces the reliance on foreign oil, there is a renewed interest in the research and development of the Fischer Tropsch synthesis for converting syngas into long chain hydrocarbon products. This report investigates some of the basic elementary steps for Fischer-Tropsch synthesis over ideal Pt, Ru and carbon-covered Pt and Ru metal surfaces by using ab initio density functional theoretical calculations. We examine in detail the adsorption sites as well as the binding energies for C, CH, CH{sub 2}, CH3 and CH4 on Pt(111), Ru(0001), 2x2-C-Pt(111) and 2x2-C-Ru(0001). The results indicate that the binding energies increase with decreasing the hydrogen in the fragment molecule, i.e. CH{sub 4} < CH{sub 3} < CH{sub 2} < CH < C. More specifically the work analyzes the elementary steps involved in the activation of methane. This is simply the reverse set of steps necessary for the hydrogenation of C to CH{sub 4}. The results indicate that these hydrocarbon intermediates bind more strongly to Ru than Pt. The introduction of co-adsorbed carbon atoms onto both Ru(0001) as well as Pt(111) significantly increased the overall energies as well as the activation barriers for C-H bond activation. The …
Date: September 11, 2003
Creator: Neurock, Matthew & Chopra, Siddharth
Object Type: Report
System: The UNT Digital Library
An Ab Initio Approach Towards Engineering Fischer-Tropsch Surface Chemistry (open access)

An Ab Initio Approach Towards Engineering Fischer-Tropsch Surface Chemistry

One of the greatest societal challenges over the next decade is the production of cheap, renewable energy for the 10 billion people that inhabit the earth. This will require the development of various energy sources which will likely include fuels derived from methane, coal, and biomass and alternatives sources such as solar, wind and nuclear energy. One approach will be to synthesize gasoline and other fuels from simpler hydrocarbons such as CO derived from methane or other U.S. based sources such as coal. Syngas (CO and H{sub 2}) can be readily converted into higher molecular weight hydrocarbons through Fischer-Tropsch synthesis. Fischer-Tropsch (FT) synthesis involves the adsorption and the activation of CO and H{sub 2}, the subsequent propagation steps including hydrogenation and carbon-carbon coupling, followed by chain termination reactions. The current commercial catalysts are supported Co and Co-alloys particles. This project set out with the following objectives in mind: (1) understand the reaction mechanisms that control FT kinetics, (2) predict how the intrinsic metal-adsorbate bond affects the sequence of elementary steps in FT, (3) establish the effects of the reaction environment on catalytic activity and selectivity, (4) construct a first-principles based algorithm that can incorporate the detailed atomic surface structure and …
Date: September 11, 2006
Creator: Neurock, Matthew
Object Type: Report
System: The UNT Digital Library
An Ab Initio Approach Towards Engineering Fischer-Tropsch Surface Chemistry (open access)

An Ab Initio Approach Towards Engineering Fischer-Tropsch Surface Chemistry

As the US seeks to develop an energy strategy that reduces the reliance on foreign oil, there is a renewed interest in research and development of the Fischer Tropsch synthesis of converting syngas into long chain hydrocarbon products. This report investigates some of the basic elementary steps for Fischer-Tropsch synthesis over ideal Co and Ru metal surfaces by using ab initio density functional theoretical calculations. This includes activation of CO of CO, the hydrogenation of CH{sub x} intermediates, and the adsorption and dissociation of water. The activation of CO is studied in detail showing a strong dependence on the surface coverage, defect sites and Co-Ru alloy formation. The barriers for CO activation over the ideal (0001) surfaces are quite high making CO activation at the terrace sites unlikely under operating conditions. The calculations for the overall reaction energies at the step edges indicate that these sites are much more reactive. The hydrogenation of the CHx intermediates occurs in a sequential fashion. CH1 was found to be the most stable intermediate over various surfaces. The barriers to form both CH* as well as CH{sub 4} are both found to be highly activated and potentially difficult steps. Water which is a reaction …
Date: September 11, 2002
Creator: Neurock, Matthew
Object Type: Report
System: The UNT Digital Library
Absorption Spectra of Broadened Sodium Resonance Lines in Presence of Rare Gases (open access)

Absorption Spectra of Broadened Sodium Resonance Lines in Presence of Rare Gases

The pressure broadening of alkali-metal lines is a fundamental problem with numerous applications. For example, the sodium resonance lines broadened by xenon are important in the production of broad spectra emitted in the HPS (High-Pressure Sodium) lamp and they potentially can be used for gas condition diagnostics. Broadened absorption lines of alkali-metal atoms are prominent in the optical spectra of brown dwarfs and understanding the broadening mechanism will help elucidate the chemical composition and atmospheric properties of those stars. The far-line wing spectra of sodium resonance lines broadened by rare gases are found to exhibit molecular characteristics such as satellites and hence the total absorption coefficients for vapors of Na atoms and perturbing rare gas atoms can be modeled as Na-RG (rare gas) molecular absorption spectra. In this work, using carefully chosen interatomic potentials for Na-RG molecules we carry out quantum-mechanical calculations for reduced absorption coefficients for vapors composed of Na-He, Na-Ar, and Na-Xe. Calculated spectra are compared to available experimental results and the agreement is good in the measured satellite positions and shapes.
Date: September 11, 2002
Creator: Chung, H-K; Shurgalin, M & Babb, J F
Object Type: Article
System: The UNT Digital Library
Advanced Simulation and Computing Fiscal Year 14 Implementation Plan, Rev. 0.5 (open access)

Advanced Simulation and Computing Fiscal Year 14 Implementation Plan, Rev. 0.5

None
Date: September 11, 2013
Creator: Meisner, R.; McCoy, M.; Archer, B. & Matzen, M.
Object Type: Report
System: The UNT Digital Library
Advanced Simulation and Computing FY13 Implementation Plan, Rev. 0.5 (open access)

Advanced Simulation and Computing FY13 Implementation Plan, Rev. 0.5

None
Date: September 11, 2012
Creator: Meisner, R.; McCoy, M.; Archer, B. & Cieslak, W.
Object Type: Report
System: The UNT Digital Library
AIRBLAST OVERPRESSURE AND DYNAMIC PRESSURE OVER VARIOUS SURFACES (open access)

AIRBLAST OVERPRESSURE AND DYNAMIC PRESSURE OVER VARIOUS SURFACES

Static overpressure and dynamic pressure versus time over surfaces processing different physical properties were measured on two tower shots, 6 and 12. On Shot 12, three surfaces were provided: the natural desert, a water surface consisting of a flooded area, and an asphalt surface. On Shot 6, desert and asphalt areas only were available. There were 123 channels of instrumentation installed for Shot 12, and 24 for Shot 6. From the data, a system of wave-form classification was devised for overpressure and dynamic-pressure- versus-time measurements. Incorporation of this system into data analysios indicates that it is possible for an ideal peak pressure to be identified with a nonideal wave form. Introducing both variables, wave form and peak pressure, into analyses reduces ambiguioties associoated with comparing results of different nuclear tests. The data show the effect of the nature of the surface upon airblast phenomena from a nuclear explosion. The effects of surface conditions upon shock phenomena are made more understandable by a review of temperature computatioons, using shock wave parameters in addition to an analysis based upon the arrioval time of the thermal pulse. A phenomenological discussion of precursor formation is presented, and comparisons are made using data from all …
Date: September 11, 1957
Creator: Sachs, D. C.; Swift, L. M. & Sauer, F. M.
Object Type: Report
System: The UNT Digital Library
Aluminum hydroxide coating thickness measurements and brushing tests on K West Basin fuel elements (open access)

Aluminum hydroxide coating thickness measurements and brushing tests on K West Basin fuel elements

Aluminum hydroxide coating thicknesses were measured on fuel elements stored in aluminum canisters in K West Basin using specially developed eddy current probes . The results were used to estimate coating inventories for MCO fuel,loading. Brushing tests successfully demonstrated the ability to remove the coating if deemed necessary prior to MCO loading.
Date: September 11, 1998
Creator: Pitner, A. L.
Object Type: Report
System: The UNT Digital Library
Analysis Of 2H-Evaporator Scale Wall [HTF-13-82] And Pot Bottom [HTF-13-77] Samples (open access)

Analysis Of 2H-Evaporator Scale Wall [HTF-13-82] And Pot Bottom [HTF-13-77] Samples

Savannah River Remediation (SRR) is planning to remove a buildup of sodium aluminosilicate scale from the 2H-evaporator pot by loading and soaking the pot with heated 1.5 M nitric acid solution. Sampling and analysis of the scale material has been performed so that uranium and plutonium isotopic analysis can be input into a Nuclear Criticality Safety Assessment (NCSA) for scale removal by chemical cleaning. Historically, since the operation of the Defense Waste Processing Facility (DWPF), silicon in the DWPF recycle stream combines with aluminum in the typical tank farm supernate to form sodium aluminosilicate scale mineral deposits in the 2H-evaporator pot and gravity drain line. The 2H-evaporator scale samples analyzed by Savannah River National Laboratory (SRNL) came from two different locations within the evaporator pot; the bottom cone sections of the 2H-evaporator pot [Sample HTF-13-77] and the wall 2H-evaporator [sample HTF-13-82]. X-ray diffraction analysis (XRD) confirmed that both the 2H-evaporator pot scale and the wall samples consist of nitrated cancrinite (a crystalline sodium aluminosilicate solid) and clarkeite (a uranium oxyhydroxide mineral). On ''as received'' basis, the bottom pot section scale sample contained an average of 2.59E+00 {+-} 1.40E-01 wt % total uranium with a U-235 enrichment of 6.12E-01 {+-} 1.48E-02 …
Date: September 11, 2013
Creator: Oji, L. N.
Object Type: Report
System: The UNT Digital Library

Analysis of Buoyancy-Driven Ventilation of Hydrogen from Buildings

The scope of work for this project includes safe building design, vehicle leak in residential garage, continual slow leak, passive, buoyancy-driven ventilation (versus mechanical), and steady-state concentration of hydrogen versus vent size.
Date: September 11, 2007
Creator: Barley, C. D.; Gawlik, K.; Ohi, J. & Hewett, R.
Object Type: Presentation
System: The UNT Digital Library
Analysis of HFIR pressurizer pump overspeed transients and relief valve performance (open access)

Analysis of HFIR pressurizer pump overspeed transients and relief valve performance

The pressurizer pump overspeed transients at the High Flux Isotope Reactor (HFIR) fall in the category of {open_quotes}increase in coolant inventory transients.{close_quotes} They are among the accident transients to be performed for Chapter 15 of the HFIR safety analysis report (SAR). The pressurizer pump speed starting to increase inadvertently to reach its maximum speed of 3,560 rpm while the reactor operates under normal conditions is the cause of this transient. Increased primary coolant system pressure due to increased pressurizer pump flow into the primary coolant head tank challenges the relief valves to open. If the relief valves do not open, increased primary coolant system pressure will challenge the integrity of the high pressure boundary. Two sets of analyses were performed to analyze the pressurizer pump overspeed transients. The purpose of the first analysis is to estimate how long it will take for the relief valves to open under different conditions and whether or not they will chatter or flutter for a considerable amount of time. The analysis estimates relief valve performance and stability using four different relief valve subsystem models. The relief valve subsystem models are not attached to the primary coolant system model. Vigorous pressure oscillations were produced in …
Date: September 11, 1992
Creator: Sozer, M. C.
Object Type: Report
System: The UNT Digital Library
Analysis of Off-Nuclear X-Ray Sources in Galaxy NGC 4945 (open access)

Analysis of Off-Nuclear X-Ray Sources in Galaxy NGC 4945

Recently, X-ray astronomy has been used to investigate objects such as galaxies, clusters of galaxies, Active Galactic Nuclei (AGN), quasars, starburst superbubbles of hot gas, X-ray binary systems, stars, supernova remnants, and interstellar and intergalactic material. By studying the x-ray emission patterns of these objects, we can gain a greater understanding of their structure and evolution. We analyze X-ray emission from the galaxy NGC 4945 using data taken by the Chandra X-ray Observatory. The Chandra Interactive Analysis of Observations (CIAO) software package was used to extract and fit energy spectra and to extract light curves for the brightest off-nuclear sources in two different observations of NGC 4945 (January, 2000 and May, 2004). A majority of sources were closely fit by both absorbed power law and absorbed bremsstrahlung models, with a significantly poorer {chi}{sup 2}/dof for the absorbed blackbody model, and most sources had little variability. This indicates that the sources are accreting binary systems with either a neutron star or black hole as the compact object. The calculated luminosities were about 10{sup 38} erg/s, which implies that the mass of the accreting object is close to 10 solar masses and must be a black hole.
Date: September 11, 2006
Creator: Harrison, Sarah M. & /SLAC, /MIT
Object Type: Report
System: The UNT Digital Library
Ancient Blacksmiths, The Iron Age, Damascus Steels, and Modern Metallurgy (open access)

Ancient Blacksmiths, The Iron Age, Damascus Steels, and Modern Metallurgy

The history of iron and Damascus steels is described through the eyes of ancient blacksmiths. For example, evidence is presented that questions why the Iron Age could not have begun at about the same time as the early Bronze Age (i.e. approximately 7000 B.C.). It is also clear that ancient blacksmiths had enough information from their forging work, together with their observation of color changes during heating and their estimate of hardness by scratch tests, to have determined some key parts of the present-day iron-carbon phase diagram. The blacksmiths' greatest artistic accomplishments were the Damascus and Japanese steel swords. The Damascus sword was famous not only for its exceptional cutting edge and toughness, but also for its beautiful surface markings. Damascus steels are ultrahigh carbon steels (UHCSs) that contain from 1.0 to 2.1%. carbon. The modern metallurgical understanding of UHCSs has revealed that remarkable properties can be obtained in these hypereutectoid steels. The results achieved in UHCSs are attributed to the ability to place the carbon, in excess of the eutectoid composition, to do useful work that enhances the high temperature processing of carbon steels and that improves the low and intermediate temperature mechanical properties.
Date: September 11, 2000
Creator: Sherby, O. D. & Wadsworth, J.
Object Type: Article
System: The UNT Digital Library
Annealing and mechanical properties of bulk Y-Ba-Cu-O. (open access)

Annealing and mechanical properties of bulk Y-Ba-Cu-O.

Single-domain melt-processed YBa{sub 2}Cu{sub 3}O{sub x}/Y{sub 2}BaCuO{sub 5} and conventional polycrystalline sintered YBa{sub 2}Cu{sub 3}O{sub x} pellets were prepared. Elastic modulus, hardness, and fracture strength were measured on selected sections cut from the pellets. Strength in the melt-processed pellets ranged from 32 to 94 MPa and was highest in the center. Variations in strength were related to microstructural features, especially Y{sub 2}BaCuO{sub 5} distribution. To improve strength, we attempted to minimize microcracking by manipulating cooling rates, annealing times, and oxygen partial pressure. Extent of cracking was evaluated by electron microscopy and change in elastic modulus and strength. We found that control of annealing reduced microcracking of the polycrystalline sintered pellets, but had little effect on the single-domain melt-processed pellets.
Date: September 11, 1998
Creator: Goretta, K. C.
Object Type: Article
System: The UNT Digital Library
Annual Progress Report. [Linear and nonlinear instability theory] (open access)

Annual Progress Report. [Linear and nonlinear instability theory]

A number of topics in nonlinear and linear instability theory are covered in this report. The nonlinear saturation of the dissipative trapped electron instability is evaluated and its amplitude compares well with existing experimental observations. The nonlinear saturation of the drift cyclotron loss-cone mode is carried out for a variety of empty loss-cone distributions. The saturation amplitude is predicted to be small and stable. An improved linear theory of the collisionless drift instability in sheared magnetic fields yields the surprising result that no instability occurs for a wide range of parameters. Finally, the bump-on-tail calculation is shown to be unchanged by some recent results of Case and Siewart, and a rough time scale is established for the transition from the O'Neil trapping regime to the final time-asymptotic result.
Date: September 11, 1978
Creator: Simon, Albert & Catto, Peter J.
Object Type: Report
System: The UNT Digital Library
Arizona Consumer's Guide to Buying a Solar Electric System (open access)

Arizona Consumer's Guide to Buying a Solar Electric System

Consumers in Arizona are showing increased interest in solar electric systems for their homes and businesses. This booklet provides basic information about buying a PV system. Photovoltaic (PV) systems are reliable, pollution free, and use a renewable source of energy-the sun. A PV system can be a substantial investment and careful planning will help ensure that you make the right decisions.
Date: September 11, 2000
Creator: Starrs, T. & Wenger, H.
Object Type: Book
System: The UNT Digital Library
Autoionization of Be-like ions following double electron capture in C sup 4+ , O sup 6+ and Ne sup 8+ ions (open access)

Autoionization of Be-like ions following double electron capture in C sup 4+ , O sup 6+ and Ne sup 8+ ions

This paper describes electron emission following the autoionization of doubly excited states in Be-like ions. The Be-like Auger states are produced by two electron capture in slow C{sup 4+}, O{sup 6+} and Ne{sup 8+} ions. These measurements were performed by means of high resolution Auger electron spectroscopy on different target gases and at different projectile energies. Line assignments and relative cross sections are given for the investigated doubly excited states and the excitation mechanism is discussed. 15 refs., 16 figs., 4 tabs.
Date: September 11, 1990
Creator: McDonald, J.W.
Object Type: Report
System: The UNT Digital Library
BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO (open access)

BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO

The principal research effort for Year 1 of the project is data compilation and the determination of the tectonic and depositional histories of the North Louisiana Salt Basin. In the first three (3) to six (6) months of Year 1, the research focus is on data compilation and the remainder of the year the emphasis is on the tectonic and depositional histories of the basin. No major problems have been encountered to date, and the project is on schedule.
Date: September 11, 2003
Creator: Mancini, Ernest A.
Object Type: Report
System: The UNT Digital Library
Beam and plasma direct converters (open access)

Beam and plasma direct converters

Two types of direct converters, one for beams and one for plasma, are under development with voltages and power densities approaching reactor-like conditions. Beam direct conversion raises the efficiency of producing neutral beams, can save millions of dollars when applied to next-generation experiments, and can improve the power balance of driven reactors. Direct conversion allows positive ion beams to be made into neutrals efficiently up to 150 keV for D/sup 0/, 225 keV for T/sup 0/ and 300 keV for /sup 3/He/sup 0/. Above these energies, the efficiency is less than 50% and falling rapidly, requiring negative ions to be used for neutral beam formation, which even they can benefit from direct conversion because the conversion fraction from negatives to neutrals is less than 100% (approximately 80% plasma cell, approximately 60% gas cell). The in-line beam direct conversion concept uses either electrostatic or magnetic fields for electron suppression. At low powers (approximately 1 kW continuous) and low voltage (10 to 15 keV), both have operated at an efficiency better than 70%.
Date: September 11, 1978
Creator: Moir, Ralph W.
Object Type: Report
System: The UNT Digital Library
Benchmark and comparisons of FEL simulation programs TDA3D and GENESIS. (open access)

Benchmark and comparisons of FEL simulation programs TDA3D and GENESIS.

A low-energy undulator test line (LEUTL) is under construction at the Advanced Photon Source (APS). This line will initially be used to demonstrate a free-electron laser (FEL) based on the self-amplified spontaneous-emission (SASE) process. The FEL simulation programs, TDA3D and GENESIS, together with several other codes have been used for the LEUTL project. In order to increase the confidence on the simulation results, we attempted to benchmark two programs TDA3D and GENESIS. The results are reported here.
Date: September 11, 1999
Creator: Chae, Y. -C. & Milton, S. V.
Object Type: Report
System: The UNT Digital Library
{Beta}-FeOOH, a new positive electrode material for lithium secondary batteries. (open access)

{Beta}-FeOOH, a new positive electrode material for lithium secondary batteries.

Beta-iron oxy-hydroxide, which exhibits a (2x2) tunnel-type structure-similar to that of {alpha}-MnO{sub 2}, was found to intercalate reversibly lithium in the tunnels. This material exhibits a potential slightly higher than 2 V with a capacity of 275 mAh/g and very good cyclic reversibility. X-ray Photoelectron Spectroscopy (XPS) investigation of discharged material showed that iron is reduced to the divalent state, and the lithium incorporated in the tunnels was purely ionic. This explains the good reversibility of this electrode material.
Date: September 11, 1998
Creator: Amine, K.
Object Type: Article
System: The UNT Digital Library
Biocide Usage in Cooling Towers in the Electric Power and Petroleum Refining Industries (open access)

Biocide Usage in Cooling Towers in the Electric Power and Petroleum Refining Industries

The conclusion of the report is that few of the surveyed facilities are having any difficulty in using and discharging the biocides they want to use.
Date: September 11, 1997
Creator: Veil, J. A.; Rice, J. K. & Raivel, M. E. S.
Object Type: Report
System: The UNT Digital Library
CH Packaging Operations Manual (open access)

CH Packaging Operations Manual

This document provides the user with instructions for assembling a payload. All the steps in Subsections 1.2, Preparing 55-Gallon Drum Payload Assembly; 1.3, Preparing "Short" 85-Gallon Drum Payload Assembly (TRUPACT-II and HalfPACT); 1.4, Preparing "Tall" 85-gallon Drum Payload Assembly (HalfPACT only); 1.5, Preparing 100-Gallon Drum Payload Assembly; 1.6, Preparing SWB Payload Assembly; and 1.7, Preparing TDOP Payload Assembly, must be completed, but may be performed in any order as long as radiological control steps are not bypassed. Transport trailer operations, package loading and unloading from transport trailers, hoisting and rigging activities such as ACGLF operations, equipment checkout and shutdown, and component inspection activities must be performed, but may be performed in any order and in parallel with other activities as long as radiological control steps are not bypassed. Steps involving OCA/ICV lid removal/installation and payload removal/loading may be performed in parallel if there are multiple operators working on the same packaging. Steps involving removal/installation of OCV/ICV upper and lower main O-rings must be performed in sequence.
Date: September 11, 2008
Creator: None, None
Object Type: Report
System: The UNT Digital Library