States

"Radiative Closure Studies for Clear Skies During the ARM 2003 Aerosol Intensive Observation Period" (open access)

"Radiative Closure Studies for Clear Skies During the ARM 2003 Aerosol Intensive Observation Period"

The Department of Energy's Atmospheric Radiation Measurement (ARM) program sponsored a large intensive observation period (IOP) to study aerosol during the month of May 2003 around the Southern Great Plains (SGP) Climate Research Facility (CRF) in north central Oklahoma. Redundant measurements of aerosol optical properties were made using different techniques at the surface as well as in vertical profile with sensors aboard two aircraft. One of the principal motivations for this experiment was to resolve the disagreement between models and measurements of diffuse horizontal broadband shortwave irradiance at the surface, especially for modest aerosol loading. This paper focuses on using the redundant aerosol and radiation measurements during this IOP to compare direct beam and diffuse horizontal broadband shortwave irradiance measurements and models at the surface for a wide range of aerosol cases that occurred during 30 clear-sky periods on 13 days of May 2003. Models and measurements are compared over a large range of solar-zenith angles. Six different models are used to assess the relative agreement among them and the measurements. Better agreement than previously achieved appears to be the result of better specification of input parameters and better measurements of irradiances than in prior studies. Biases between modeled and …
Date: April 1, 2006
Creator: Michalsky, J. J.; Anderson, G. P.; Barnard, J.; Delamere, J.; Gueymard, C.; Kato, S. et al.
Object Type: Article
System: The UNT Digital Library
Development of Semi-Stochastic Algorithm for Optimizing Alloy Composition of High-Temperature Austenitic Stainless Steels (H-Series) for Desired Mechanical and Corrosion Properties. (open access)

Development of Semi-Stochastic Algorithm for Optimizing Alloy Composition of High-Temperature Austenitic Stainless Steels (H-Series) for Desired Mechanical and Corrosion Properties.

The goal of this project was to adapt and use an advanced semi-stochastic algorithm for constrained multiobjective optimization and combine it with experimental testing and verification to determine optimum concentrations of alloying elements in heat-resistant and corrosion-resistant H-series stainless steel alloys that will simultaneously maximize a number of alloy's mechanical and corrosion properties.
Date: June 1, 2006
Creator: Dulikravich, George S.; Sikka, Vinod K. & Muralidharan, G.
Object Type: Report
System: The UNT Digital Library
Tolerance of Three-Stage CIGS Deposition to Variations Imposed by Roll-to-Roll Processing: Final Technical Report, May 2003 - September 2005 (open access)

Tolerance of Three-Stage CIGS Deposition to Variations Imposed by Roll-to-Roll Processing: Final Technical Report, May 2003 - September 2005

Three-stage co-evaporation of CIGS imposes stringent limits on the parameter space if high-efficient devices are to result. Substrate temperatures during the 1st stage (as well as during the 2nd and 3rd stage), Se partial pressure, and amount of Na supplied are critical for good nucleation, proper In-Ga-selenide precursor phase, and diffusion of Cu into the precursor, as well as diffusion of Ga through the film. In addition, the degree of Cu-rich excursion impacts maximum performance and process tolerance. Enveloping the above is the basic time-temperature profile inextricably linked to the metals delivery rates. Although high-efficiency, three-stage deposited CIGS devices on the R&D scale are grown at about 20-45 minutes to thicknesses of 2 to 2.5 m, the latter is not a viable approach for an economic manufacturing process. At Global Solar Energy, Inc., CIGS films are typically grown in about 6 minutes to thicknesses of less than 2 m. At the same time, the emissivity and thermal conductivity of stainless steel is vastly different from that of glass, and the reduced growth time poses restrictions on the substrate temperature ramp rates and diffusion of species (reaction kinetics). Material compatibility in the highly corrosive Se environment places limitations on the substrate …
Date: January 1, 2006
Creator: Beck, M. E. & Britt, J. S.
Object Type: Report
System: The UNT Digital Library
Testing State-Space Controls for the Controls Advanced Research Turbine: Preprint (open access)

Testing State-Space Controls for the Controls Advanced Research Turbine: Preprint

Control can improve wind turbine performance by enhancing energy capture and reducing dynamic loads. At the National Renewable Energy Laboratory, we are implementing and testing state-space controls on the Controls Advanced Research Turbine (CART), a turbine specifically configured to test advanced controls. We show the design of control systems to regulate turbine speed in Region 3 using rotor collective pitch and reduce dynamic loads in Regions 2 and 3 using generator torque. These controls enhance damping in the first drive train torsion mode. We base these designs on sensors typically used in commercial turbines. We evaluate the performance of these controls by showing field test results. We also compare results from these modern controllers to results from a baseline proportional integral controller for the CART. Finally, we report conclusions to this work and outline future studies.
Date: January 1, 2006
Creator: Wright, A. D.; Fingersh, L. J. & Balas, M. J.
Object Type: Article
System: The UNT Digital Library
Save Energy Now (open access)

Save Energy Now

This DOE Industrial Technologies Program brochure informs industrial audiences about Save Energy Now, part of ''Easy Ways to Save Energy'', a national campaign to save energy and ensure energy security.
Date: January 1, 2006
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Optical Blade Position Tracking System Test (open access)

Optical Blade Position Tracking System Test

The Optical Blade Position Tracking System Test measures the blade deflection along the span of the blade using simple off-the-shelf infrared security cameras along with blade-mounted retro-reflective tape and video image processing hardware and software to obtain these measurements.
Date: January 1, 2006
Creator: Fingersh, L. J.
Object Type: Report
System: The UNT Digital Library
Process R&D for CIS-Based Thin-Film PV: Final Technical Report, April 2002 - April 2005 (open access)

Process R&D for CIS-Based Thin-Film PV: Final Technical Report, April 2002 - April 2005

The primary objectives of this Shell Solar Industries subcontract are to address key near-term technical R&D issues for continued CIS product improvement; continue process development for increased production capacity; develop processes capable of significantly contributing to DOE 2020 PV shipment goals; advance mid- and longer-term R&D needed by industry for future product competitiveness including improving module performance, decreasing production process costs per watt produced, and improving reliability; and perform aggressive module lifetime R&D directed at developing packages that address the DOE goal for modules that will last up to 30 years while retaining 80% of initial power. These production R&D results, production volume, efficiency, high line yield, and advances in understanding are major accomplishments. The demonstrated and maintained high production yield is a major accomplishment supporting attractive cost projections for CIS. Process R&D at successive levels of CIS production has led to the continued demonstration of the prerequisites for commitment to large-scale commercialization. Process and packaging R&D during this and previous subcontracts has demonstrated the potential for further cost and performance improvements.
Date: January 1, 2006
Creator: Tarrant, D. E. & Gay, R. R.
Object Type: Report
System: The UNT Digital Library
Pepper Pot Emittance Meter (open access)

Pepper Pot Emittance Meter

N/A
Date: July 1, 2006
Creator: Pikin, A.; Kponou, A.; Ritter, J. & Zajic, V.
Object Type: Report
System: The UNT Digital Library
Aperture and vacuum aspects of the PHENIX and STAR detector upgrade beampipe (open access)

Aperture and vacuum aspects of the PHENIX and STAR detector upgrade beampipe

N/A
Date: August 1, 2006
Creator: Montag, C.; Hseuh, H. C. & Fischer, W.
Object Type: Report
System: The UNT Digital Library
Observations of Direct Excitation of the Betatron Spectrum by Mains Harmonics in RHIC (open access)

Observations of Direct Excitation of the Betatron Spectrum by Mains Harmonics in RHIC

N/A
Date: September 1, 2006
Creator: P., Cameron; Gasior, M.; Jones, R. & Tang, C-Y.
Object Type: Report
System: The UNT Digital Library
Analysis of FY 2005 System Operational Failures (open access)

Analysis of FY 2005 System Operational Failures

N/A
Date: June 1, 2006
Creator: Michnoff, R. & Turbush, H.
Object Type: Report
System: The UNT Digital Library
Beam Evolution with Time in Electron Cooling and in Intrabeam Scattering (open access)

Beam Evolution with Time in Electron Cooling and in Intrabeam Scattering

N/A
Date: June 1, 2006
Creator: Parzen, G.
Object Type: Report
System: The UNT Digital Library
Testing the Specificity of Primers to Environmental Ammonia Monooxygenase (amoA) Genes in Groundwater Treated with Urea to Promote Calcite Precipitation (open access)

Testing the Specificity of Primers to Environmental Ammonia Monooxygenase (amoA) Genes in Groundwater Treated with Urea to Promote Calcite Precipitation

Bacterial ammonia monooxygenase (amoA) genes in DNA isolated from microorganisms in groundwater were characterized by amplification of amoA DNA using polymerase chain reaction (PCR), Restriction Fragment Length Polymorphism (RFLP) analysis, and sequencing. The amoA gene is characteristic of ammonia oxidizing bacteria (AOB). The DNA extracts were acquired from an experiment where dilute molasses and urea were sequentially introduced into a well in the Eastern Snake River Plain Aquifer (ESRPA) in Idaho to examine whether such amendments could stimulate enhanced ureolytic activity. The hydrolysis of urea into ammonium and carbonate serves as the basis for a potential remediation technique for trace metals and radionuclide contaminants that can co-precipitate in calcite. The ammonium ion resulting from ureolysis can promote the growth of AOB. The goal of this work was to investigate the effectiveness of primers designed for quantitative PCR of environmental amoA genes and to evaluate the effect of the molasses and urea amendments upon the population diversity of groundwater AOB. PCR primers designed to target a portion of the amoA gene were used to amplify amoA gene sequences in the groundwater DNA extracts. Following PCR, amplified gene products were cloned and the clones were characterized by RFLP, a DNA restriction technique …
Date: January 1, 2006
Creator: Freeman, S.; Reed, D.W. & Fujita, Y.
Object Type: Article
System: The UNT Digital Library
Physiological Adjustments of Leaf Respiration to Atmospheric Warming in Betula alleghaniensis and Quercus rubra (open access)

Physiological Adjustments of Leaf Respiration to Atmospheric Warming in Betula alleghaniensis and Quercus rubra

Global air temperatures are predicted to rise 1° to 4.5° Celsius by the year 2100. This climatic change is expected to have a great effect on the succession and migration of temperate deciduous forest species. Most physiologically based models of forest response to climatic change focus on the ecosystems as a whole instead of on individual tree species, assuming that the effects of warming on respiration are generally the same for each species, and that processes can not adjust to a changing climate. Experimental data suggest that physiological adjustments are possible, but there is a lack of data in deciduous species. In order to correctly model the effects of climate change on temperate species, species-specific respiration acclimation (adjustment) to rising temperatures is being determined in this experiment. Two temperate deciduous tree species Betula alleghaniensis (BA) and Quercus rubra (QR) were grown over a span of four years in open-top chambers and subjected to two different temperature treatments; ambient and ambient plus 4° Celsius (E4). Between 0530 hours and 1100 hours, respiration was measured over a range of leaf temperatures on several comparable, fully expanded leaves in each treatment. Circular punches were taken from the leaves and dried at 60°C to …
Date: January 1, 2006
Creator: Vollmar, A. & Gunderson, C.
Object Type: Article
System: The UNT Digital Library
Journal of Undergraduate Research, Volume 6, 2006 (open access)

Journal of Undergraduate Research, Volume 6, 2006

None
Date: January 1, 2006
Creator: Faletra, P.; Schuetz, A.; Cherkerzian, D & Clark, T.
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library
AGS-less RIA with FFAG Accelerators (open access)

AGS-less RIA with FFAG Accelerators

N/A
Date: May 1, 2006
Creator: Ruggiero, Alessandro G.
Object Type: Report
System: The UNT Digital Library
Advances with the RHIC Proton-Carbon Polarimeters for the 2006 Run (open access)

Advances with the RHIC Proton-Carbon Polarimeters for the 2006 Run

N/A
Date: July 1, 2006
Creator: Wood, J.; Alekseev, I.; Bravar, A.; Bunce, G.; Dhawan, S.; Gill, R. et al.
Object Type: Report
System: The UNT Digital Library
Electron Gun for RHIC EBIS (open access)

Electron Gun for RHIC EBIS

N/A
Date: July 1, 2006
Creator: A., Pikin
Object Type: Report
System: The UNT Digital Library
Eddy Current Imaging of Machined Grooves on a Nickel Wave Strip (open access)

Eddy Current Imaging of Machined Grooves on a Nickel Wave Strip

White paper proposal to client at Y-12 for eddy current inspection
Date: January 1, 2006
Creator: Andersen, Eric S.; Mathews, Royce & Sandness, Gerald A.
Object Type: Report
System: The UNT Digital Library
Optimization of strain-relaxed InPyAs1-y buffers for InGaAs thermophotovoltaic devices. (open access)

Optimization of strain-relaxed InPyAs1-y buffers for InGaAs thermophotovoltaic devices.

None
Date: July 1, 2006
Creator: Cederberg, Jeffrey George & Lee, Stephen Roger
Object Type: Report
System: The UNT Digital Library
Thermal Analysis for Arc Flash Resistor and Enclosure (open access)

Thermal Analysis for Arc Flash Resistor and Enclosure

N/A
Date: November 1, 2006
Creator: V., Badea & Bellavia, S.
Object Type: Report
System: The UNT Digital Library
Aspen Global Change Institute Summer Science Sessions (open access)

Aspen Global Change Institute Summer Science Sessions

The Aspen Global Change Institute (AGCI) successfully organized and convened six interdisciplinary meetings over the course of award NNG04GA21G. The topics of the meetings were consistent with a range of issues, goals and objectives as described within the NASA Earth Science Enterprise Strategic Plan and more broadly by the US Global Change Research Program/Our Changing Planet, the more recent Climate Change Program Strategic Plan and the NSF Pathways report. The meetings were chaired by two or more leaders from within the disciplinary focus of each session. 222 scholars for a total of 1097 participants-days were convened under the auspices of this award. The overall goal of each AGCI session is to further the understanding of Earth system science and global environmental change through interdisciplinary dialog. The format and structure of the meetings allows for presentation by each participant, in-depth discussion by the whole group, and smaller working group and synthesis activities. The size of the group is important in terms of the group dynamics and interaction, and the ability for each participant's work to be adequately presented and discussed within the duration of the meeting, while still allowing time for synthesis
Date: October 1, 2006
Creator: Katzenberger, John & Kaye, Jack A
Object Type: Report
System: The UNT Digital Library
Characterization of a TK6-Bcl-xL gly-159-ala Human Lymphoblast Clone (open access)

Characterization of a TK6-Bcl-xL gly-159-ala Human Lymphoblast Clone

TK6 cells are a well-characterized human B-lymphoblast cell line derived from WIL-2 cells. A derivative of the TK6 cell line that was stably transfected to express a mutated form of the anti-apoptotic protein Bcl-xL (TK6-Bcl-xL gly-159- ala clone #38) is compared with the parent cell line. Four parameters were evaluated for each cell line: growth under normal conditions, plating efficiency, and frequency of spontaneous mutation to 6‑thioguanine resistance (hypoxanthine phosphoribosyl transferase locus) or trifluorothymidine resistance (thymidine kinase locus). We conclude that the mutated Bcl-xL protein did not affect growth under normal conditions, plating efficiency or spontaneous mutation frequencies at the thymidine kinase (TK) locus. Results at the hypoxanthine phosphoribosyl transferase (HPRT) locus were inconclusive. A mutant fraction for TK6‑Bcl-xL gly-159-ala clone #38 cells exposed to 150cGy of 160kVp x-rays was also calculated. Exposure to x-irradiation increased the mutant fraction of TK6‑Bcl-xL gly-159-ala clone #38 cells.
Date: January 1, 2006
Creator: Chyall, L.: Gauny, S. & Kronenberg, A.
Object Type: Article
System: The UNT Digital Library
Ordered Nucleation Sites for the Growth of Zinc Oxide Nanofibers (open access)

Ordered Nucleation Sites for the Growth of Zinc Oxide Nanofibers

Organic photovoltaics (OPVs) offer a promising route to low cost photovoltaic (PV) technology that can be inexpensively manufactured on a large scale for use in power generation and commercial products. Solar power conversion efficiencies of laboratory scale OPV devices have recently reached ~5%; however, projected efficiencies of at least 10% will be required for commercialization. An analogous approach that has arisen recently that can potentially increase efficiencies employs metal oxide semiconductors as the electron acceptor, creating a hybrid organic-inorganic device. This approach offers the advantage that the conduction band of the oxide can be tuned in a systematic way through doping, thus potentially achieving higher photovoltages in the device. Additionally, nanostructures of these materials can be easily grown from precursor solutions, providing a technique to precisely control the nanoscale geometry. This work focuses on using ZnO, which is known to have high electron mobility (>100 cm2/Vs), as the electron acceptor. Nanofibers of ZnO can be grown from precursors such as zinc acetate or zinc nitrate to form arrays of nanofibers into which a conjugated polymer can be intercalated to form a composite PV device. The morphology of the nanofiber array is critical to the performance of the device, but current …
Date: January 1, 2006
Creator: Wang, J.; Ginley, D.S. & Shaheen, S.
Object Type: Article
System: The UNT Digital Library