High Efficiency Solar Power via Separated Photo and Voltaic Pathways (open access)

High Efficiency Solar Power via Separated Photo and Voltaic Pathways

This project demonstrates a novel nanostructured solar cell architecture capable of achieving high efficiency levels that is relatively simple and inexpensive to manufacture. The high efficiency will be achieved by the novel structure that separates the path of the photons from the path of the generated charge carriers. In this way, the photon path can be long for maximum light absorption, while the path for carriers can be short for maximum electronic energy harvesting. The combination of maximum light absorption coupled with maximum carrier harvesting is the basis for the expected high efficiency. The project will develop high efficiency solar cell prototypes utilizing this unique nanostructured architecture. The project addresses the fundamental limitation inherent in all current solar cell designs, and which opens a pathway to development for high efficiency solar cells at low cost. Realizing this goal will result in a levelized cost of electricity in the range of 10¢/kWh, which would achieve the long-sought goal of making photovoltaic electricity cost competitive with fossil-fuel generated electricity without any governmental subsidies. This breakthrough would spur the already rapid growth in the photovoltaic industry to an explosive pace, with significant, widespread benefit to the national economy and the nation’s energy security. …
Date: February 17, 2009
Creator: Naughton, Michael J.
Object Type: Report
System: The UNT Digital Library
An Integrated Functional Genomics Consortium to Increase Carbon Sequestration in Poplars: Optimizing Aboveground Carbon Gain (open access)

An Integrated Functional Genomics Consortium to Increase Carbon Sequestration in Poplars: Optimizing Aboveground Carbon Gain

This project used gene expression patterns from two forest Free-Air CO2 Enrichment (FACE) experiments (Aspen FACE in northern Wisconsin and POPFACE in Italy) to examine ways to increase the aboveground carbon sequestration potential of poplars (Populus). The aim was to use patterns of global gene expression to identify candidate genes for increased carbon sequestration. Gene expression studies were linked to physiological measurements in order to elucidate bottlenecks in carbon acquisition in trees grown in elevated CO2 conditions. Delayed senescence allowing additional carbon uptake late in the growing season, was also examined, and expression of target genes was tested in elite P. deltoides x P. trichocarpa hybrids. In Populus euramericana, gene expression was sensitive to elevated CO2, but the response depended on the developmental age of the leaves. Most differentially expressed genes were upregulated in elevated CO2 in young leaves, while most were downregulated in elevated CO2 in semi-mature leaves. In P. deltoides x P. trichocarpa hybrids, leaf development and leaf quality traits, including leaf area, leaf shape, epidermal cell area, stomatal number, specific leaf area, and canopy senescence were sensitive to elevated CO2. Significant increases under elevated CO2 occurred for both above- and belowground growth in the F-2 generation. Three …
Date: February 17, 2009
Creator: Karnosky, David F (deceased); Podila, G Krishna & Burton, Andrew J (for DF Karnosky)
Object Type: Report
System: The UNT Digital Library
A Femtosecond-Level Fiber-Optics Timing Distribution System Using Frequency-Offset Interferometry (open access)

A Femtosecond-Level Fiber-Optics Timing Distribution System Using Frequency-Offset Interferometry

An optical fiber-based frequency and timing distribution system based on the principle of heterodyne interferometry has been in development at LBNL for several years. The fiber drift corrector has evolved from an RF-based to an optical-based system, from mechanical correctors (piezo and optical trombone) to fully electronic, and the electronics from analog to fully digital, all using inexpensive off-the-shelf commodity fiber components. Short-term optical phase jitter and long-term phase drift are both in the femtosecond range over distribution paths of 2 km or more.
Date: October 17, 2009
Creator: Staples, J. W.; Byrd, J.; Doolittle, L.; Huang, G. & Wilcox, R.
Object Type: Article
System: The UNT Digital Library
Evaluating Cumulative Ecosystem Response to Restoration Projects in the Lower Columbia River and Estuary, 2008 (open access)

Evaluating Cumulative Ecosystem Response to Restoration Projects in the Lower Columbia River and Estuary, 2008

Draft annual report for the Cumulative Effects Study for the US Army Corps of Engineers, Portland District
Date: December 17, 2009
Creator: Johnson, Gary E.; Diefenderfer, Heida L.; Borde, Amy B.; Dawley, Earl M.; Ebberts, Blaine D.; Roegner, G. Curtis et al.
Object Type: Report
System: The UNT Digital Library
Analytical Data Report of Grab Samples Collected From BP-5 Operable Unit G Well (C5853) (open access)

Analytical Data Report of Grab Samples Collected From BP-5 Operable Unit G Well (C5853)

This is an analytical data report for sediment samples received from CHPRC.
Date: August 17, 2009
Creator: Lindberg, Michael J.
Object Type: Report
System: The UNT Digital Library
CHARACTERIZATION OF THE TANK 18F SAMPLES (open access)

CHARACTERIZATION OF THE TANK 18F SAMPLES

The Savannah River National Laboratory (SRNL) was asked by Liquid Waste Operations to characterize Tank 18F closure samples. Tank 18F slurry samples analyzed included the liquid and solid fractions derived from the 'as-received' slurry materials along with the floor scrape bottom Tank 18F wet solids. These samples were taken from Tank 18F in March 2009 and made available to SRNL in the same month. Because of limited amounts of solids observed in Tank 18F samples, the samples from the north quadrants of the tank were combined into one North Tank 18F Hemisphere sample and similarly the south quadrant samples were combined into one South Tank 18F Hemisphere sample. These samples were delivered to the SRNL shielded cell. The Tank 18F samples were analyzed for radiological, chemical and elemental components. Where analytical methods yielded additional contaminants other than those requested by the customer, these results were also reported. The target detection limits for isotopes analyzed were 1E-04 {micro}Ci/g for most radionuclides and customer desired detection values of 1E-05 {micro}Ci/g for I-129, Pa-231, Np-237, and Ra-226. While many of the minimum detection limits, as specified in the technical task request and task technical and quality assurance plans were met for the species …
Date: December 17, 2009
Creator: Oji, L.; Click, D. & Diprete, D.
Object Type: Report
System: The UNT Digital Library
Ponderomotive Acceleration of Hot Electrons in Tenuous Plasmas (open access)

Ponderomotive Acceleration of Hot Electrons in Tenuous Plasmas

The oscillation-center Hamiltonian is derived for a relativistic electron injected with an arbitrary momentum in a linearly polarized laser pulse propagating in tenuous plasma, assuming that the pulse length is smaller than the plasma wavelength. For hot electrons generated at collisions with ions under intense laser drive, multiple regimes of ponderomotive acceleration are identified and the laser dispersion is shown to affect the process at plasma densities down to 1017 cm−3. Assuming a/ϒg << 1, which prevents net acceleration of the cold plasma, it is also shown that the normalized energy ϒ of hot electrons accelerated from the initial energy ϒo < , ⌈ does not exceed ⌈ ~ aϒg, where a is the normalized laser field, and ϒg is the group velocity Lorentz factor. Yet ϒ ~ ⌈ is attained within a wide range of initial conditions; hence a cutoff in the hot electron distribution is predicted.
Date: February 17, 2009
Creator: V.I. Geyko and G.M. Fraiman, I.Y. Dodin and N.J. Fisch
Object Type: Report
System: The UNT Digital Library
Moving toward multilateral mechanisms for the fuel cycle (open access)

Moving toward multilateral mechanisms for the fuel cycle

Multilateral mechanisms for the fuel cycle are seen as a potentially important way to create an industrial infrastructure that will support a renaissance and at the same time not contribute to the risk of nuclear proliferation. In this way, international nuclear fuel cycle centers for enrichment can help to provide an assurance of supply of nuclear fuel that will reduce the likelihood that individual states will pursue this sensitive technology, which can be used to produce nuclear material directly usable nuclear weapons. Multinational participation in such mechanisms can also potentially promote transparency, build confidence, and make the implementation of IAEA safeguards more effective or more efficient. At the same time, it is important to ensure that there is no dissemination of sensitive technology. The Russian Federation has taken a lead role in this area by establishing an International Uranium Enrichment Center (IUEC) for the provision of enrichment services at its uranium enrichment plant located at the Angarsk Electrolysis Chemical Complex (AECC). This paper describes how the IUEe is organized, who its members are, and the steps that it has taken both to provide an assured supply of nuclear fuel and to ensure protection of sensitive technology. It also describes the …
Date: April 17, 2009
Creator: Panasyuk,A.; Rosenthal,M. & Efremov, G. V.
Object Type: Article
System: The UNT Digital Library
Dynamic quantum clustering: a tool for visual exploration of structures in data (open access)

Dynamic quantum clustering: a tool for visual exploration of structures in data

A given set of data-points in some feature space may be associated with a Schroedinger equation whose potential is determined by the data. This is known to lead to good clustering solutions. Here we extend this approach into a full-fledged dynamical scheme using a time-dependent Schroedinger equation. Moreover, we approximate this Hamiltonian formalism by a truncated calculation within a set of Gaussian wave functions (coherent states) centered around the original points. This allows for analytic evaluation of the time evolution of all such states, opening up the possibility of exploration of relationships among data-points through observation of varying dynamical-distances among points and convergence of points into clusters. This formalism may be further supplemented by preprocessing, such as dimensional reduction through singular value decomposition or feature filtering.
Date: October 17, 2009
Creator: Weinstein, Marvin
Object Type: Article
System: The UNT Digital Library
A Search for B^{+} \to \ell^{+} \nu_{\ell} Recoiling Against B^{-} \to D^{(*)0}\ell^{-}\bar{\nu}X (open access)

A Search for B^{+} \to \ell^{+} \nu_{\ell} Recoiling Against B^{-} \to D^{(*)0}\ell^{-}\bar{\nu}X

We present a search for the decay B{sup +} {yields} {ell}{sup +} {nu}{sub {ell}} ({ell} = {tau}, {mu}, or e) in (458.9 {+-} 5.1) x 10{sup 6} {Upsilon}(4S) decays recorded with the BABAR detector at the SLAC PEP-IIB-Factory. A sample of events with one reconstructed exclusive semi-leptonic B decay (B{sup -} {yields} D{sup 0} {ell}{sup -}{bar {nu}}X) is selected, and in the recoil a search for B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}} signal is performed. The {tau} is identified in the following channels: {tau}{sup +} {yields} e{sup +}{nu}{sub e}{nu}{sub {tau}}, {tau}{sup +} {yields} {mu}{sup +}{nu}{sub {mu}}{nu}{sub {tau}}, {tau}{sup +} {yields} {pi}{sup +}{nu}{sub {tau}}, and {tau}{sup +} {yields} {pi}{sup +}{pi}{sup 0}{nu}{sub {tau}}. The analysis strategy and the statistical procedure is set up for branching fraction extraction or upper limit determination. We determine from the dataset a preliminary measurement of {Beta}(B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}}) = (1.8 {+-} 0.8 {+-} 0.1) x 10{sup -4}, which excludes zero at 2.4{sigma}, and f{sub B} = 230 {+-} 57 MeV. Combination with the hadronically tagged measurement yields {Beta}(B{sup +} {yields} e{sup +}{nu}{sub e}) = (1.8 {+-} 0.6) x 10{sup -4}. We also set preliminary limits on the branching fractions at {Beta}(B{sup +} {yields} e{sup …
Date: April 17, 2009
Creator: Aubert, Bernard; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E. et al.
Object Type: Article
System: The UNT Digital Library
2008 Sandia National Laboratory Annual Illness and Injury Surveillance Report (open access)

2008 Sandia National Laboratory Annual Illness and Injury Surveillance Report

The U.S. Department of Energy’s (DOE) commitment to assuring the health and safety of its workers includes the conduct of epidemiologic surveillance activities that provide an early warning system for health problems among workers. The Illness and Injury Surveillance Program monitors illnesses and health conditions that result in an absence of workdays, occupational injuries and illnesses, and disabilities and deaths among current workers.
Date: September 17, 2009
Creator: United States. Department of Energy. Office of Health, Safety, and Security.
Object Type: Report
System: The UNT Digital Library
Particle-In-Cell/Monte Carlo Simulation of Ion Back BomBardment in a High Average Current RF Photo-Gun (open access)

Particle-In-Cell/Monte Carlo Simulation of Ion Back BomBardment in a High Average Current RF Photo-Gun

In this paper, we report on study of ion back bombardment in a high average current radio-frequency (RF) photo-gun using a particle-in-cell/Monte Carlo simulation method. Using this method, we systematically studied effects of gas pressure, RF frequency, RF initial phase, electric field profile, magnetic field, laser repetition rate, different ion species on ion particle line density distribution, kinetic energy spectrum, and ion power line density distribution back bombardment onto the photocathode. Those simulation results suggested that effects of ion back bombardment could increase linearly with the background gas pressure and laser repetition rate. The RF frequency has significantly affected the ion motion inside the gun so that the ion power deposition on the photocathode in an RF gun can be several orders of magnitude lower than that in a DC gun. The ion back bombardment can be minimized by appropriately choosing the electric field profile and the initial phase.
Date: October 17, 2009
Creator: Qiang, J.
Object Type: Article
System: The UNT Digital Library
STATISTICAL EVALUATION OF PROCESSING DATA FROM THE RH RU HG MATRIX STUDY (open access)

STATISTICAL EVALUATION OF PROCESSING DATA FROM THE RH RU HG MATRIX STUDY

An evaluation of the statistical significance of Rh, Ru, and Hg on DWPF Sludge Receipt and Adjustment Tank (SRAT) cycle catalytic hydrogen generation and process chemistry was conducted by the Savannah River National Laboratory (SRNL) using a full-factorial experimental design. This test design can identify significant interactions between these three species in addition to individual effects. Statistical modeling of data from the Rh-Ru-Hg matrix study has been completed. Preliminary data and conclusions were given in an earlier report. This final report concludes the work on the Rh-Ru-Hg matrix study. Modeling results are summarized below. Rhodium was found to: Promote increased total hydrogen mass; Promote an increase in the maximum hydrogen generation rate; Promote an increase in the hydrogen generation rate shortly after acid addition; Shorten the elapsed time between acid addition and the maximum hydrogen generation rate; Increase formate loss; Inhibit NO{sub 2} and total NO{sub x} off-gas species formation; and Reduce nitrite-to-nitrate conversion. Ruthenium was found to: Promote increased total hydrogen mass; Promote an increase in the maximum hydrogen generation rate; Promote an increase in the hydrogen generation rate in the second half of the SRAT cycle; Promote an increase in total CO{sub 2} generated; Increase formate loss; Promote …
Date: April 17, 2009
Creator: Koopman, D
Object Type: Report
System: The UNT Digital Library
FRAMES-2.0 Software System: Frames 2.0 Pest Integration (F2PEST) (open access)

FRAMES-2.0 Software System: Frames 2.0 Pest Integration (F2PEST)

The implementation of the FRAMES 2.0 F2PEST module is described, including requirements, design, and specifications of the software. This module integrates the PEST parameter estimation software within the FRAMES 2.0 environmental modeling framework. A test case is presented.
Date: June 17, 2009
Creator: Castleton, Karl J. & Meyer, Philip D.
Object Type: Report
System: The UNT Digital Library
Higher-Twist Dynamics in Large Transverse Momentum Hadron Production (open access)

Higher-Twist Dynamics in Large Transverse Momentum Hadron Production

A scaling law analysis of the world data on inclusive large-p{sub {perpendicular}} hadron production in hadronic collisions is carried out. A significant deviation from leading-twist perturbative QCD predictions at next-to-leading order is reported. The observed discrepancy is largest at high values of x{sub {perpendicular}} = 2p{sub {perpendicular}}/{radical}s. In contrast, the production of prompt photons and jets exhibits the scaling behavior which is close to the conformal limit, in agreement with the leading-twist expectation. These results bring evidence for a non-negligible contribution of higher-twist processes in large-p{sub {perpendicular}} hadron production in hadronic collisions, where the hadron is produced directly in the hard subprocess rather than by gluon or quark jet fragmentation. Predictions for scaling exponents at RHIC and LHC are given, and it is suggested to trigger the isolated large-p{sub {perpendicular}} hadron production to enhance higher-twist processes.
Date: December 17, 2009
Creator: Arleo, Francois; Brodsky, Stanley J.; Hwang, Dae Sung & Sickles, Anne M.
Object Type: Article
System: The UNT Digital Library
Monthly Health Information Report. June 1-30, 1950 (open access)

Monthly Health Information Report. June 1-30, 1950

None
Date: July 17, 2009
Creator: Boozer, A. H.
Object Type: Report
System: The UNT Digital Library
Construction of Large Period Symplectic Maps by Interpolative Methods (open access)

Construction of Large Period Symplectic Maps by Interpolative Methods

The goal is to construct a symplectic evolution map for a large section of an accelerator, say a full turn of a large ring or a long wiggler. We start with an accurate tracking algorithm for single particles, which is allowed to be slightly non-symplectic. By tracking many particles for a distance S one acquires sufficient data to construct the mixed-variable generator of a symplectic map for evolution over S, given in terms of interpolatory functions. Two ways to find the generator are considered: (1) Find its gradient from tracking data, then the generator itself as a line integral. (2) Compute the action integral on many orbits. A test of method (1) has been made in a difficult example: a full turn map for an electron ring with strong nonlinearity near the dynamic aperture. The method succeeds at fairly large amplitudes, but there are technical difficulties near the dynamic aperture due to oddly shaped interpolation domains. For a generally applicable algorithm we propose method (2), realized with meshless interpolation methods.
Date: December 17, 2009
Creator: Warnock, Robert; Cai, Yunhai & Ellison, James A.
Object Type: Article
System: The UNT Digital Library
Final Hazard Categorization for the Remediation of the 118-D-1, 118-D-2, 118-D-3, 118-H-1, 118-H-2, and 118-H-3 Solid Waste Burial Grounds (open access)

Final Hazard Categorization for the Remediation of the 118-D-1, 118-D-2, 118-D-3, 118-H-1, 118-H-2, and 118-H-3 Solid Waste Burial Grounds

This report presents the final hazard categorization for the remediation of the 118-D-1, 118-D-2, 118-D-3 Burial Grounds located within the 100-D/DR Area of the Hanford Site and the 118-H-1, 118-H-2, and 118-H-3 Burial Grounds located within the 100-H Area of the Hanford Site. A material at risk calculation was performed that determined the radiological inventory for each burial ground to be Hazard Category 3.
Date: June 17, 2009
Creator: Ludowise, J.D.
Object Type: Report
System: The UNT Digital Library
Polarized Antenna Splitting Functions (open access)

Polarized Antenna Splitting Functions

We consider parton showers based on radiation from QCD dipoles or 'antennae'. These showers are built from 2 {yields} 3 parton splitting processes. The question then arises of what functions replace the Altarelli-Parisi splitting functions in this approach. We give a detailed answer to this question, applicable to antenna showers in which partons carry definite helicity, and to both initial- and final-state emissions.
Date: October 17, 2009
Creator: Larkoski, Andrew J. & Peskin, Michael E.
Object Type: Article
System: The UNT Digital Library
Digital Divide in Sub-Saharan African Universities: Recommendations and Monitoring (open access)

Digital Divide in Sub-Saharan African Universities: Recommendations and Monitoring

The Digital Divide prevents Africa from taking advantages of new information technologies. One of the most urgent priorities is to bring the Internet in African Universities, Research, and Learning Centers to the level of other regions of the world. eGY-Africa, and the Sharing Knowledge Foundation are two bottom-up initiatives by scientists to secure better cyber-infrastructure and Internet facilities in Africa. Recommendations by the present scientific communities are being formulated at national, regional and international levels. The Internet capabilities are well documented at country level overall, but this is not the case at the University level. The snapshot of the Internet status in universities in 17 African countries, obtained by a questionnaire survey, is consistent with measures of Internet penetration in the corresponding country. The monitoring of Internet performance has been proposed to those African universities to provide an information base for arguing the need to improve the coverage for Africa. A pilot program is recommended that will start scientific collaboration with Europe in western Africa using ICT. The program will lay the foundations for the arrival of new technologies like Grids.
Date: December 17, 2009
Creator: Barry, Boubakar; Chukwuma, Victor; Petitdidier, Monique; Cottrell, Les & Bartons, Charles
Object Type: Article
System: The UNT Digital Library
Focusing DIRC Design for Super B (open access)

Focusing DIRC Design for Super B

In this paper we present a new design of the Focusing DIRC for the Barrel PID to be used at the proposed Super-B factory. The new imaging optics is made of a solid Fused Silica block with a double folded optics using two mirrors, one cylindrical and one flat, focusing photons on a detector plane conveniently accessible for the detector access. The design assumes that the BaBar bar boxes are re-used without any modification, including the wedges and windows. Each bar box will have its own focusing block, which will contain 40 H-9500 (or H-8500) MaPMTs according to present thinking. There are 12 bar boxes in the entire detector, so the entire SuperB FDIRC system would have 480 MaPMTs. The design is very compact and therefore reduces sensitivity to the background. The chosen MaPMTs are fast enough to be able both to reject the background and to perform the chromatic correction. The 3D optics simulation is coded with the Mathematica program. The work in this paper was a basis of the LDRD proposal made to SLAC in 2009 [1].
Date: December 17, 2009
Creator: Va'Vra, J.
Object Type: Report
System: The UNT Digital Library
Phase I Archaeological Survey of Parcel ED-3 and Historic Assessement of the Happy Valley Worker Camp Roane County, Tennessee (open access)

Phase I Archaeological Survey of Parcel ED-3 and Historic Assessement of the Happy Valley Worker Camp Roane County, Tennessee

Parcel ED-3 was the location of a portion of 'Happy Valley', a temporary worker housing area occupied from 1943 to 1947 during the construction of the K-25 Oak Ridge Gaseous Diffusion Plant. The project was carried out under subcontract for the Department of Energy. The survey report will be used in the preparation of an Environmental Assessment under the National Environmental Policy Act (NEPA). New South Associates conducted a Phase I Archaeological Survey of Parcel ED-3 at the US Department of Energy's Oak Ridge Reservation in Roane County, Tennessee. The survey was conducted in two parts. The first survey was carried out in 2008 and covered an area measuring approximately 110 acres. The second survey took place in 2009 and focused on 72 acres west of the first survey area. The objective of the surveys was to identify any archaeological remains associated with Happy Valley and any additional sites on the property and to assess these sites for National Register eligibility. New South Associates also conducted a historic assessment to gather information on Happy Valley. This historic assessment was used in conjunction with the archaeological survey to evaluate the significance of the Happy Valley site. Archaeological remains of Happy Valley …
Date: August 17, 2009
Creator: Associates, New South
Object Type: Report
System: The UNT Digital Library
Studies of Bystander Effects in 3-D Tissue Systems Using a Low-LET Microbeam (open access)

Studies of Bystander Effects in 3-D Tissue Systems Using a Low-LET Microbeam

It is now accepted that biological effects may occur in cells that were not themselves traversed by ionizing radiation but are close to those that were. Little is known about the mechanism underlying such a bystander effect, although cell-to-cell communication is thought to be important. Previous work demonstrated a significant bystander effect for clonogenic survival and oncogenic transformation in C3H 10T(1/2) cells. Additional studies were undertaken to assess the importance of the degree of cell-to-cell contact at the time of irradiation on the magnitude of this bystander effect by varying the cell density. When 10% of cells were exposed to a range of 2-12 alpha particles, a significantly greater number of cells were inactivated when cells were irradiated at high density than at low density. In addition, the oncogenic transformation frequency was significantly higher in high-density cultures. These results suggest that when a cell is hit by radiation, the transmission of the bystander signal through cell-to-cell contact is an important mediator of the effect, implicating the involvement of intracellular communication through gap junctions. Additional studies to address the relationship between the bystander effect and the adaptive response were undertaken. A novel apparatus, where targeted and non-targeted cells were grown in …
Date: July 17, 2009
Creator: Brenner, David J.
Object Type: Report
System: The UNT Digital Library
Letter Report - Verification Survey of Final Grids at the David Witherspoon, Inc. 1630 Site Knoxville, Tennessee (open access)

Letter Report - Verification Survey of Final Grids at the David Witherspoon, Inc. 1630 Site Knoxville, Tennessee

Conduct verification surveys of grids at the DWI 1630 Site in Knoxville, Tennessee. The independent verification team (IVT) from ORISE, conducted verification activities in whole and partial grids, as completed by BJC. ORISE site activities included gamma surface scans and soil sampling within 33 grids; G11 through G14; H11 through H15; X14, X15, X19, and X21; J13 through J15 and J17 through J21; K7 through K9 and K13 through K15; L13 through L15; and M14 through M16
Date: February 17, 2009
Creator: Weaver, P. C.
Object Type: Report
System: The UNT Digital Library