On The Reproducibility of Seasonal Land-surface Climate (open access)

On The Reproducibility of Seasonal Land-surface Climate

The sensitivity of the continental seasonal climate to initial conditions is estimated from an ensemble of decadal simulations of an atmospheric general circulation model with the same specifications of radiative forcings and monthly ocean boundary conditions, but with different initial states of atmosphere and land. As measures of the ''reproducibility'' of continental climate for different initial conditions, spatio-temporal correlations are computed across paired realizations of eleven model land-surface variables in which the seasonal cycle is either included or excluded--the former case being pertinent to climate simulation, and the latter to seasonal anomaly prediction. It is found that the land-surface variables which include the seasonal cycle are impacted only marginally by changes in initial conditions; moreover, their seasonal climatologies exhibit high spatial reproducibility. In contrast, the reproducibility of a seasonal land-surface anomaly is generally low, although it is substantially higher in the Tropics; its spatial reproducibility also markedly fluctuates in tandem with warm and cold phases of the El Nino/Southern Oscillation. However, the overall degree of reproducibility depends strongly on the particular land-surface anomaly considered. It is also shown that the predictability of a land-surface anomaly implied by its reproducibility statistics is consistent with what is inferred from more conventional predictability …
Date: October 22, 2004
Creator: Phillips, T J
Object Type: Article
System: The UNT Digital Library
Chemical Plant Security (open access)

Chemical Plant Security

This report highlights the reasons why chemical plants are susceptible to security breaches due to the ineffectiveness of proposed congressional mandates.
Date: October 22, 2004
Creator: Schierow, Linda-Jo
Object Type: Report
System: The UNT Digital Library
Merchant Banking: Mixing Banking and Commerce Under the Gramm-Leach-Bliley Act (open access)

Merchant Banking: Mixing Banking and Commerce Under the Gramm-Leach-Bliley Act

None
Date: October 22, 2004
Creator: unknown
Object Type: Report
System: The UNT Digital Library
The 9/11 Commission and a National Counterterrorism Center: Issues and Options for Congress (open access)

The 9/11 Commission and a National Counterterrorism Center: Issues and Options for Congress

This report examines a number of issues as Congress considers codification of an NCTC. One issue is whether the centralization remedy the commission has recommended fits the problems associated specifically with the 9/11 intelligence failure, and perhaps more broadly, the systematic maladies affecting the Intelligence Community. There are at least four options for congressional consideration: (1) NCTC with intelligence and operational planning duties, (2) NCTC restricted to an intelligence role, (3) NCTC restricted to an operational planning role, and (4) status quo plus-viewing the newly forming collected entity as a pilot potential NCTC. As one of its 41 recommendations, the 9/11 Commission recommended the creation of a National Counterterroism Center (NCTC).
Date: October 22, 2004
Creator: Masse, Todd
Object Type: Report
System: The UNT Digital Library
Report of the Solar and Atmospheric Neutrino Working Group (open access)

Report of the Solar and Atmospheric Neutrino Working Group

The highest priority of the Solar and Atmospheric Neutrino Experiment Working Group is the development of a real-time, precision experiment that measures the pp solar neutrino flux. A measurement of the pp solar neutrino flux, in comparison with the existing precision measurements of the high energy {sup 8}B neutrino flux, will demonstrate the transition between vacuum and matter-dominated oscillations, thereby quantitatively testing a fundamental prediction of the standard scenario of neutrino flavor transformation. The initial solar neutrino beam is pure {nu}{sub e}, which also permits sensitive tests for sterile neutrinos. The pp experiment will also permit a significantly improved determination of {theta}{sub 12} and, together with other solar neutrino measurements, either a measurement of {theta}{sub 13} or a constraint a factor of two lower than existing bounds. In combination with the essential pre-requisite experiments that will measure the {sup 7}Be solar neutrino flux with a precision of 5%, a measurement of the pp solar neutrino flux will constitute a sensitive test for non-standard energy generation mechanisms within the Sun. The Standard Solar Model predicts that the pp and {sup 7}Be neutrinos together constitute more than 98% of the solar neutrino flux. The comparison of the solar luminosity measured via neutrinos …
Date: October 22, 2004
Creator: Back, H.; Bahcall, J. N.; Bernabeu, J.; Boulay, M. G.; Bowles, T.; Calaprice, F. et al.
Object Type: Report
System: The UNT Digital Library
Development of a Novel Catalyst for NO Decomposition (open access)

Development of a Novel Catalyst for NO Decomposition

Air pollution arising from the emission of nitrogen oxides as a result of combustion taking place in boilers, furnaces and engines, has increasingly been recognized as a problem. New methods to remove NO{sub x} emissions significantly and economically must be developed. The current technology for post-combustion removal of NO is the selective catalytic reduction (SCR) of NO by ammonia or possibly by a hydrocarbon such as methane. The catalytic decomposition of NO to give N{sub 2} will be preferable to the SCR process because it will eliminate the costs and operating problems associated with the use of an external reducing species. The most promising decomposition catalysts are transition metal (especially copper)-exchanged zeolites, perovskites, and noble metals supported on metal oxides such as alumina, silica, and ceria. The main shortcoming of the noble metal reducible oxide (NMRO) catalysts is that they are prone to deactivation by oxygen. It has been reported that catalysts containing tin oxide show oxygen adsorption behavior that may involve hydroxyl groups attached to the tin oxide. This is different than that observed with other noble metal-metal oxide combinations, which have the oxygen adsorbing on the noble metal and subsequently spilling over to the metal oxide. This observation …
Date: October 22, 2004
Creator: Akyurtlu, Ates & Akyurtlu, Jale F.
Object Type: Report
System: The UNT Digital Library
Laser triggered injection of electrons in a laser wakefield accelerator with the colliding pulse method (open access)

Laser triggered injection of electrons in a laser wakefield accelerator with the colliding pulse method

An injection scheme for a laser wakefield accelerator that employs a counter propagating laser (colliding with the drive laser pulse, used to generate a plasma wake) is discussed. The threshold laser intensity for electron injection into the wakefield was analyzed using a heuristic model based on phase-space island overlap. Analysis shows that the injection can be performed using modest counter propagating laser intensity a{sub 1} < 0.5 for a drive laser intensity of a{sub 0} = 1.0. Preliminary experiments were preformed using a drive beam and colliding beam. Charge enhancement by the colliding pulse was observed. Increasing the signal-to-noise ratio by means of a preformed plasma channel is discussed.
Date: October 22, 2004
Creator: Nakamura, K.; Fubiani, G.; Geddes, C. G. R.; Michel, P.; van Tilborg, J.; Toth, C. et al.
Object Type: Article
System: The UNT Digital Library
High efficiency, radiation-hard solar cells (open access)

High efficiency, radiation-hard solar cells

The direct gap of the In{sub 1-x}Ga{sub x}N alloy system extends continuously from InN (0.7 eV, in the near IR) to GaN (3.4 eV, in the mid-ultraviolet). This opens the intriguing possibility of using this single ternary alloy system in single or multi-junction (MJ) solar cells of the type used for space-based surveillance satellites. To evaluate the suitability of In{sub 1-x}Ga{sub x}N as a material for space applications, high quality thin films were grown with molecular beam epitaxy and extensive damage testing with electron, proton, and alpha particle radiation was performed. Using the room temperature photoluminescence intensity as a indirect measure of minority carrier lifetime, it is shown that In{sub 1-x}Ga{sub x}N retains its optoelectronic properties at radiation damage doses at least 2 orders of magnitude higher than the damage thresholds of the materials (GaAs and GaInP) currently used in high efficiency MJ cells. This indicates that the In{sub 1-x}Ga{sub x}N is well-suited for the future development of ultra radiation-hard optoelectronics. Critical issues affecting development of solar cells using this material system were addressed. The presence of an electron-rich surface layer in InN and In{sub 1-x}Ga{sub x}N (0 < x < 0.63) was investigated; it was shown that this is …
Date: October 22, 2004
Creator: Ager, J. W., III & Walukiewicz, W.
Object Type: Report
System: The UNT Digital Library
Coherent transition radiation from a laser wakefield accelerator as an electron bunch diagnostic (open access)

Coherent transition radiation from a laser wakefield accelerator as an electron bunch diagnostic

The observation and modeling of coherent transition radiation from femtosecond laser accelerated electron bunches is discussed. The coherent transition radiation, scaling quadratically with bunch charge, is generated as the electrons transit the plasma-vacuum boundary. Due to the limited transverse radius of the plasma boundary, diffraction effects will strongly modify the angular distribution and the total energy radiated is reduced compared to an infinite transverse boundary. The multi-nC electron bunches, concentrated in a length of a few plasma periods (several tens of microns), experience partial charge neutralization while propagating inside the plasma towards the boundary. This reduces the space-charge blowout of the beam, allowing for coherent radiation at relatively high frequencies (several THz). The charge distribution of the electron bunch at the plasma-vacuum boundary can be derived from Fourier analysis of the coherent part of the transition radiation spectrum. A Michelson interferometer was used to measure the coherent spectrum, and electron bunches with duration on the order of 50 fs (rms) were observed.
Date: October 22, 2004
Creator: van Tilborg, J.; Geddes, C. G. R.; Toth, C.; Esarey, E.; Schroeder, C. B.; Martin, M. C. et al.
Object Type: Article
System: The UNT Digital Library
A Real Time Coal Content/Ore Grade (C2OG) Sensor, Technical Report: July - August 2004 (open access)

A Real Time Coal Content/Ore Grade (C2OG) Sensor, Technical Report: July - August 2004

This thirteenth quarterly technical report describes data collection at the Stillwater Mine and an additional improvement to the lighting system. The data collection system was returned to the Stillwater Mine during this reporting period and a large amount of data was collected. The data will be analyzed and correlated with fire assays in the next reporting period. The majority of work done this quarter has been devoted to collecting data from cores scanned in the Stillwater Mining Company core room. This work is somewhat tedious and tiresome, but essential to: (1) obtain enough data to reliably determine the correlation between assay results and spectral imaging results; (2) find bugs and glitches in the system that arise only periodically or after long periods of use; and (3) obtain data on the natural (and man-made) variations in the Stillwater ore that may confuse the machine vision algorithms.
Date: October 22, 2004
Creator: Swanson, Rand
Object Type: Report
System: The UNT Digital Library
Oxidation of elemental mercury by chlorine: Gas phase, Surface,and Photo-induced reaction pathways (open access)

Oxidation of elemental mercury by chlorine: Gas phase, Surface,and Photo-induced reaction pathways

Accurate oxidation rate constants of mercury gas are needed for determining its dispersion and lifetime in the atmosphere. They would also help in developing a technology for the control of mercury emissions from coal-fired power plants. However, it is difficult to establish the accurate rate constants primarily due to the fact that mercury easily adsorbs on solid surface and its reactions can be catalyzed by the surface. We have demonstrated a procedure that allows the determination of gas phase, surface-induced, and photo-induced contributions in the kinetic study of the oxidation of mercury by chlorine gas. The kinetics was studied using reactors with various surface to volume ratios. The effect of the surface and the photo irradiation on the reaction was taken into consideration. The pressure dependent study revealed that the gas phase oxidation was a three-body collision process. The third order rate constant was determined to be 7.5({+-}0.2) x 10{sup -39} mL{sup 2} molecules{sup -2}s{sup -1} with N{sub 2} as the third body at 297 {+-} 1 K. The surface induced reaction on quartz window was second order and the rate constant was 2.7 x 10{sup -17} mL{sup 2} molecules{sup -1} cm{sup -2} sec. Meanwhile, the 253.7 nm photon employed …
Date: October 22, 2004
Creator: Yan, Nai-Qiang; Liu, Shou-Heng & Chang, Shih-Ger
Object Type: Article
System: The UNT Digital Library
Supersonic Propagation of Ionization Waves in an Under-Dense, Laser-Produced Plasma (open access)

Supersonic Propagation of Ionization Waves in an Under-Dense, Laser-Produced Plasma

We observe a laser-driven supersonic ionization wave heating a mm-scale plasma of sub-critical density up to 2-3 keV electron temperatures. Propagation velocities initially 10 times the sound speed were measured by means of time-resolved x-ray imaging diagnostics. The measured ionization wave trajectory is modeled analytically and by a 2D radiation-hydrodynamics code. The comparison to the modeling suggests that nonlocal heat transport effects may contribute to the attenuation of the heat wave propagation.
Date: October 22, 2004
Creator: Constantin, C.; Back, C. A.; Fournier, K. B.; Gregori, G.; Landen, O. L.; Glenzer, S. H. et al.
Object Type: Article
System: The UNT Digital Library
Comprehensive Assignment of Mass Spectral Signatures from Individual Bacillus atrophaeus Spores in Matrix-Free Bioaerosol Mass Spectrometry (open access)

Comprehensive Assignment of Mass Spectral Signatures from Individual Bacillus atrophaeus Spores in Matrix-Free Bioaerosol Mass Spectrometry

We have conducted studies to fully characterize the mass spectral signature of individual Bacillus atrophaeus, previously known as Bacillus subtilis var niger or Bacillus globigii, spores obtained in matrix-free bioaerosol mass spectrometry (BAMS). Mass spectra of spores grown in unlabeled, {sup 13}C-labeled and {sup 15}N-labeled growth media are used to determine the number of carbon and nitrogen atoms associated with each mass peak. To determine the parent ion structure associated with fragment ions present in the spore spectra, the mass-to-charge (m/z) fragmentation pattern of several chemical standards was obtained. Our results agree with prior assignments of dipicolinic acid, amino acids and calcium complex ions made in the spore mass spectra. Identity of several previously unidentified mass peaks, key to recognition of Bacillus spore by matrix-free BAMS, is revealed. Specifically, a set of fragment peaks in the negative polarity is shown to be consistent with the fragmentation pattern of purine nucleobase containing compounds. The identity of m/z=+74, a marker peak that helps discriminate Bacillus atrophaeus from Bacillus thuringiensis spores grown in rich medium, is surprisingly a non-description, viz. [N{sub 1}C{sub 4}H{sub 12}]{sup +}. A probable precursor molecule for the [N{sub 1}C{sub 4}H{sub 12}]{sup +} ion observed in spore spectra is trimethyl …
Date: October 22, 2004
Creator: Srivastava, A; Pitesky, M; Steele, P; Tobias, H; Fergenson, D P; Horn, J et al.
Object Type: Article
System: The UNT Digital Library
Committee of the Whole: Stages of Action on Measures (open access)

Committee of the Whole: Stages of Action on Measures

This report provides information about the Stages of Action on Measures on Committee of the Whole.
Date: October 22, 2004
Creator: Beth, Richard S.
Object Type: Report
System: The UNT Digital Library
How Special Rules Regulate Calling up Measures for Consideration in the House (open access)

How Special Rules Regulate Calling up Measures for Consideration in the House

This report provides an overview of how special rules regulate calling up measures for consideration in the House.
Date: October 22, 2004
Creator: Beth, Richard S.
Object Type: Report
System: The UNT Digital Library
Civilian Nuclear Waste Disposal (open access)

Civilian Nuclear Waste Disposal

This report mainly provides information about the Civilian Nuclear Waste Disposal.Federal policy is based on the premise that nuclear waste can be disposed of safety.
Date: October 22, 2004
Creator: Holt, Mark
Object Type: Report
System: The UNT Digital Library
Senate Committee Reports: Required Contents (open access)

Senate Committee Reports: Required Contents

This report briefly describes Senate rules and statutes that specify information that must be included as part of the written report about the purposes and provisions of a proposed measure. Senate committees also may include additional items in their reports.
Date: October 22, 2004
Creator: Carr, Thomas P.
Object Type: Report
System: The UNT Digital Library
THERMAL CONDUCTIVITY OF NON-REPOSITORY LITHOSTRATIGRAPHIC LAYERS (open access)

THERMAL CONDUCTIVITY OF NON-REPOSITORY LITHOSTRATIGRAPHIC LAYERS

This model report addresses activities described in ''Technical Work Plan for: Near-Field Environment and Transport Thermal Properties and Analysis Reports Integration'' (BSC 2004 [DIRS 171708]). The model develops values for thermal conductivity, and its uncertainty, for the nonrepository layers of Yucca Mountain; in addition, the model provides estimates for matrix porosity and dry bulk density for the nonrepository layers. The studied lithostratigraphic units, as identified in the ''Geologic Framework Model'' (GFM 2000) (BSC 2004 [DIRS 170029]), are the Timber Mountain Group, the Tiva Canyon Tuff, the Yucca Mountain Tuff, the Pah Canyon Tuff, the Topopah Spring Tuff (excluding the repository layers), the Calico Hills Formation, the Prow Pass Tuff, the Bullfrog Tuff, and the Tram Tuff. The deepest model units of the GFM (Tund and Paleozoic) are excluded from this study because no data suitable for model input are available. The parameter estimates developed in this report are used as input to various models and calculations that simulate heat transport through the rock mass. Specifically, analysis model reports that use product output from this report are: (1) Drift-scale coupled processes (DST and TH seepage) models; (2) Drift degradation analysis; (3) Multiscale thermohydrologic model; and (4) Ventilation model and analysis report. …
Date: October 22, 2004
Creator: JONES, R.
Object Type: Report
System: The UNT Digital Library
Time-Resolved Single-State Measurements of the Electronic Structure of Isochoric Heated Copper (open access)

Time-Resolved Single-State Measurements of the Electronic Structure of Isochoric Heated Copper

Time-resolved x-ray photoelectron spectroscopy is used to probe the non-steady-state evolution of the valence band electronic structure of laser heated ultra-thin (50 nm) Cu. Single-shot x-ray laser induced time-of-flight photoelectron spectroscopy with picosecond time resolution is used in conjunction with optical measurements of the disassembly dynamics that have shown the existence of a metastable liquid phase in fs-laser heated Cu foils persisting 4-5 ps. This metastable phase is studied using a 527 nm wavelength 400 fs laser pulse containing 0.1-2.5 mJ laser energy focused in a large 500 x 700 {micro}m{sup 2} spot to create heated conditions of 0.07-1.8 x 10{sup 12} W cm{sup -2} intensity. Valence band photoemission spectra showing the changing occupancy of the Cu 3d level with heating are presented. These are the first picosecond x-ray laser time-resolved photoemission spectra of laser-heated ultra-thin Cu foil showing changes in electronic structure. The ultrafast nature of this technique lends itself to true single-state measurements of shocked and heated materials.
Date: October 22, 2004
Creator: Nelson, A J; Dunn, J; Widmann, K; Ao, T; Ping, Y; Hunter, J et al.
Object Type: Article
System: The UNT Digital Library
Thermal Effects in Intense Laser-Plasma Interactions (open access)

Thermal Effects in Intense Laser-Plasma Interactions

We present an overview of a new warm fluid model that incorporates leading-order kinetic corrections to the cold fluid model without making any near-equilibrium assumptions. In the quasi-static limit we obtain analytical expressions for the momentum spread and show excellent agreement with solutions of the full time-dependant equations. It is shown that over a large range of initial plasma temperatures, the fields are relatively insensitive to the pressure force. We discuss implications of this work for model validation.
Date: October 22, 2004
Creator: Shadwick, B. A.; Tarkenton, G. M. & Esarey, E. H.
Object Type: Article
System: The UNT Digital Library
[NASA’s Space Shuttle Columbia: Quick Facts and Issues for Congress, October 22, 2004] (open access)

[NASA’s Space Shuttle Columbia: Quick Facts and Issues for Congress, October 22, 2004]

This report discusses the investigation and aftermath of Columbia after the space shuttle broke apart upon its return to Earth. Updated October 22, 2004.
Date: October 22, 2004
Creator: Smith, Marcia S.
Object Type: Report
System: The UNT Digital Library
Texas Register, Volume 29, Number 43, Pages 9739-9938, October 22, 2004 (open access)

Texas Register, Volume 29, Number 43, Pages 9739-9938, October 22, 2004

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date: October 22, 2004
Creator: Texas. Secretary of State.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Sudan: The Darfur Crisis and the Status of the North-South Negotiations (open access)

Sudan: The Darfur Crisis and the Status of the North-South Negotiations

None
Date: October 22, 2004
Creator: Dagne, Theodore S. & Everett, Bathsheaba
Object Type: Report
System: The UNT Digital Library
Military Medical Care Services: Questions and Answers (open access)

Military Medical Care Services: Questions and Answers

None
Date: October 22, 2004
Creator: Best, Richard A., Jr.
Object Type: Report
System: The UNT Digital Library