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21-kW Thin-Film PV Technology Validation -- An NREL/Solar Energy Centre of India MOU Cooperative Project (open access)

21-kW Thin-Film PV Technology Validation -- An NREL/Solar Energy Centre of India MOU Cooperative Project

This paper summarizes findings during a one-week (27-31 October 2003) site visit to the Thin-Film Technology Test Bed at India's Solar Energy Centre (SEC) near New Delhi. The U.S. and Indian governments signed a Memorandum of Understanding in March 2000 to undertake a 50-50 cost-shared 21-kW thin-film PV technology validation project to evaluate the performance of thin-film photovoltaic (PV) modules under Indian climatic conditions. This project benefits Indian researchers by giving them experience with cost-effective PV materials, and it benefits the United States because data will be sent to the appropriate U.S. thin-film PV manufacturers for evaluation and analysis. During the visit, NREL personnel engaged in technical discussions regarding thin-film PV technologies with Ministry of Non-Conventional Energy Sources engineers and scientists. Issues included inspecting the newly constructed arrays, discussing better methods of electrically loading the PV arrays, taking I-V traces, and gathering baseline I-V data.
Date: January 1, 2005
Creator: McNutt, P. F. & Ullal, H. S.
System: The UNT Digital Library
3D Magnetotelluric characterization of the COSO GeothermalField (open access)

3D Magnetotelluric characterization of the COSO GeothermalField

Knowledge of the subsurface electrical resistivity/conductivity can contribute to a better understanding of complex hydrothermal systems, typified by Coso geothermal field, through mapping the geometry (bounds and controlling structures) over existing production. Three-dimensional magnetotelluric (MT) inversion is now an emerging technology for characterizing the resistivity structures of complex geothermal systems. The method appears to hold great promise, but histories exploiting truly 3D inversion that demonstrate the advantages that can be gained by acquiring and analyzing MT data in three dimensions are still few in number. This project will address said issue, by applying 3D MT forward modeling and inversion to a MT data set acquired over the Coso geothermal field. The goal of the project is to provide the capability to image large geothermal reservoirs in a single self-consistent model. Initial analysis of the Coso MT data has been carried out using 2D MT imaging technology to construct an initial 3D resistivity model from a series of 2D resistivity images obtained using the inline electric field measurements (Zxy impedance elements) along different measurement transects. This model will be subsequently refined through a 3D inversion process. The initial 3D resistivity model clearly shows the controlling geological structures possibly influencing well production …
Date: January 1, 2005
Creator: Newman, Gregory A.; Hoversten, Michael; Gasperikova, Erika & Wannamaker, Philip E.
System: The UNT Digital Library
Abundance of green tree frogs and insects in artificial canopy gaps in a bottomland hardwood forest. (open access)

Abundance of green tree frogs and insects in artificial canopy gaps in a bottomland hardwood forest.

Horn, Scott, James L. Hanula, Michael D. Ulyshen, and John C. Kilgo. 2005. Abundance of green tree frogs and insects in artificial canopy gaps in a bottomland hardwood forest. Am. Midl. Nat. 153:321-326. Abstract: We found more green tree frogs (Hyla cinerea) in canopy gaps than in closed canopy forest. Of the 331 green tree frogs observed, 88% were in canopy gaps. Likewise, higher numbers and biomasses of insects were captured in the open gap habitat. Flies were the most commonly collected insect group accounting for 54% of the total capture. These data suggest that one reason green tree frogs were more abundant in canopy gaps was the increased availability of prey and that small canopy gaps provide early successional habitats that are beneficial to green tree frog populations.
Date: January 1, 2005
Creator: Horn, Scott; Hanula, James L.; Ulyshen, Michael D. & Kilgo, John C.
System: The UNT Digital Library
According to the Goal: How Eliyahu Goldratt Helps Organizations Examine Their Processes to Achieve Maximum Results (open access)

According to the Goal: How Eliyahu Goldratt Helps Organizations Examine Their Processes to Achieve Maximum Results

Paper analyzes Eliyahu Goldratt’s Theory of Constraints and discusses how it's proposed business model has helped companies who implement it.
Date: 2005
Creator: Winter, Chrisitan
System: The UNT Digital Library
Advanced Heat Transfer and Thermal Storage Fluids (open access)

Advanced Heat Transfer and Thermal Storage Fluids

The design of the next generation solar parabolic trough systems for power production will require the development of new thermal energy storage options with improved economics or operational characteristics. Current heat-transfer fluids such as VP-1?, which consists of a eutectic mixture of biphenyl and diphenyl oxide, allow a maximum operating temperature of ca. 300 C, a limit above which the vapor pressure would become too high and would require pressure-rated tanks. The use of VP-1? also suffers from a freezing point around 13 C that requires heating during cold periods. One of the goals for future trough systems is the use of heat-transfer fluids that can act as thermal storage media and that allow operating temperatures around 425 C combined with lower limits around 0 C. This paper presents an outline of our latest approach toward the development of such thermal storage fluids.
Date: January 1, 2005
Creator: Moens, L. & Blake, D.
System: The UNT Digital Library
Advanced Indoor Module Light-Soaking Facility (open access)

Advanced Indoor Module Light-Soaking Facility

An overview of the accelerated, indoor light-soaking test station is presented in this paper, along with data obtained for six modules that underwent exposure. The station comprises a climate-controlled chamber equipped with a solar simulator that allows 1-sun light intensity exposure. Concurrently, we monitor the electrical characteristics of multiple PV modules and exercise active control over their electrical bias using programmable electronic loads, interfaced to a data acquisition system that acquires power-tracking and current-voltage data. This capability allows us to the test different bias conditions and to cyclically alternate between them. Additionally, we can vary the light intensity and module temperatures to garner realistic temperature coefficients of module performance. Data obtained on cadmium telluride (CdTe) and amorphous silicon (a-Si) modules are presented.
Date: January 1, 2005
Creator: del Cueto, J. A.; Osterwald, C. & Pruett, J.
System: The UNT Digital Library
Advances in Solar Radiometry and Metrology (open access)

Advances in Solar Radiometry and Metrology

The Solar Radiometry and Metrology task at the National Renewable Energy Laboratory (NREL) provides traceable optical radiometric calibrations and measurements to photovoltaic (PV) researchers and the PV industry. Traceability of NREL solar radiometer calibrations to the World Radiometric Reference (WRR) was accomplished during the NREL Pyrheliometer Comparison in October 2003. The task has calibrated 10 spectral and more than 180 broadband radiometers for solar measurements. Other accomplishments include characterization of pyranometer thermal offset errors with laboratory and spectral modeling tools; developing a simple scheme to correct pyranometer data for known responsivity variations; and measuring detailed spectral distributions of the NREL High Intensity Pulsed Solar Simulator (HIPSS) as a function of lamp voltage and time. The optical metrology functions support the NREL Measurement and Characterization Task effort for ISO 17025 accreditation of NREL Solar Reference Cell Calibrations. Optical metrology functions have been integrated into the NREL quality system and audited for ISO17025 compliance.
Date: January 1, 2005
Creator: Myers, D.; Andreas, A.; Reda, I.; Gotseff, P.; Wilcox, S.; Stoffel, T. et al.
System: The UNT Digital Library
Advances in the In-House CdTe Research Activities at NREL (open access)

Advances in the In-House CdTe Research Activities at NREL

NREL in-house CdTe research activities have impacted a broad range of recent program priorities. Studies aimed at industrially relevant applications have produced new materials and processes that enhance the performance of devices based on commercial materials (e.g., soda-lime glass, SnO2:F). Preliminary tests of the effectiveness of these novel components using large-scale processes have been encouraging. Similarly, electro- and nano-probe techniques have been developed and used to study the evolution and function of CdTe grain boundaries. Finally, cathodoluminescence (CL) and photoluminescence (PL) studies on single-crystal samples have yielded improved understanding of how various processes may combine to produce important defects in CdTe films.
Date: January 1, 2005
Creator: Gessert, T.; Wu, X.; Dhere, R.; Moutinho, H.; Smith, S.; Romero, M. et al.
System: The UNT Digital Library
[After a Fashion, January 2005] (open access)

[After a Fashion, January 2005]

Article about the Golden Globe Awards, Erin Elmore, and the author's receipt of the Media Correspondent Award from Philanthropy World magazine.
Date: January 2005
Creator: Moser, Stephen MacMillan
System: The UNT Digital Library
Analysis of eddy current distributions in the CMS magnet yoke during the solenoid discharge (open access)

Analysis of eddy current distributions in the CMS magnet yoke during the solenoid discharge

Flux loops have been installed on selected segments of the magnetic flux return yoke of the 4 T superconducting coil of the Compact Muon Solenoid (CMS) detector under construction at CERN. Voltages induced in the loops during discharge of the solenoid will be sampled on-line during the entire discharge and integrated off-line to provide a measurement of the initial magnetic flux density in steel at the maximum field to an accuracy of a few percent. Although the discharge of the solenoid is rather slow (190 s time constant), the influence of eddy currents induced in the yoke elements should be estimated. The calculation of eddy currents is performed with Vector Fields program ELEKTRA. The results of calculations are reported.
Date: January 1, 2005
Creator: Klyukhin, V. I.; Campi, D.; Cure, B.; Gaddi, A.; Gerwig, H.; Grillet, J. P. et al.
System: The UNT Digital Library
Analysis of the habitat of Henslow's sparrows and Grasshopper sparrows compared to random grassland areas (open access)

Analysis of the habitat of Henslow's sparrows and Grasshopper sparrows compared to random grassland areas

Henslow's Sparrows are endangered prairie birds, and Grasshopper Sparrows are considered rare prairie birds. Both of these birds were abundant in Illinois, but their populations have been declining due to loss of the grasslands. This begins an ongoing study of the birds habitat so Fermilab can develop a land management plan for the Henslow's and Grasshoppers. The Henslow's were found at ten sites and Grasshoppers at eight sites. Once the birds were located, the vegetation at their sites was studied. Measurements of the maximum plant height, average plant height, and duff height were taken and estimates of the percent of grass, forbs, duff, and bare ground were recorded for each square meter studied. The same measurements were taken at ten random grassland sites on Fermilab property. Several t-tests were performed on the data, and it was found that both Henslow's Sparrows and Grasshopper Sparrows preferred areas with a larger percentage of grass than random areas. Henslow's also preferred areas with less bare ground than random areas, while Grasshoppers preferred areas with more bare ground than random areas. In addition, Grasshopper Sparrows preferred a lower percentage of forbs than was found in random areas and a shorter average plant height than …
Date: January 1, 2005
Creator: Maier, Kristen; Walton, Rod & Kasper, Peter
System: The UNT Digital Library
Analytical Methodologies for Detection of Gamma-Valerolactone, Delta-Valerolactone, Acephate and Azinphos Methyl and Their Associated Metabolites in Complex Biological Matrices (open access)

Analytical Methodologies for Detection of Gamma-Valerolactone, Delta-Valerolactone, Acephate and Azinphos Methyl and Their Associated Metabolites in Complex Biological Matrices

Non-invasive biomonitoring for chemicals of interest in law enforcement and similar monitoring of pesticides, together with their metabolites, can not only save money but can lead to faster medical attention for individuals exposed to these chemicals. This study describes methods developed for the analysis of gamma-valerolactone (GVL), delta-valerolactone (DVL), acephate, and azinphos methyl in saliva and serum. Liquid chromatography/mass spectrometry (LC/MS) operated in the negative and positive ion mode and gas chromatography/mass spectrometry (GC/MS) were used to analyze GVL and DVL. Although both analytical techniques worked well, lower detection limits were obtained with GC/MS. The lactones and their corresponding sodium salts were spiked into both saliva and serum. The lactones were isolated from saliva or serum using newly developed extraction techniques and then subsequently analyzed using GC/MS. The sodium salts of the lactones are nonvolatile and require derivatization prior to analysis by this method. N-methyl-N-(t-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA) was ultimately selected as the reagent for derivatization because the acidic conditions required for reactions with diazomethane caused the salts to undergo intramolecular cyclization to the corresponding lactones. In vitro studies were conducted using rat liver microsomes to determine other metabolites associated with these compounds. Azinphos methyl and acephate are classified as organophosphate pesticides, …
Date: January 1, 2005
Creator: Zink, Erica; Clark, Ryan; Grant, Karen; Campbell, James & Hoppe, Erik
System: The UNT Digital Library
Application of Combinatorial Tools for Solar Cell Improvement -- New High Performance Transparent Conducting Oxides (open access)

Application of Combinatorial Tools for Solar Cell Improvement -- New High Performance Transparent Conducting Oxides

Transparent conducting oxides (TCOs) can serve a variety of important functions in thin film photovoltaics such as transparent electrical contacts, antireflection coatings and chemical barriers. Two areas of particular interest are TCOs that can be deposited at low temperatures and TCOs with high carrier mobilities. We have employed combinatorial high-throughput approaches to investigate both these areas. Conductivities of s = 2500 W-1-cm-1 have been obtained for In-Zn-O (IZO) films deposited at 100 C and s > 5000 W-1-cm-1 for In-Ti-O (ITiO) and In-Mo-O (IMO) films deposited at 550 C. The highest mobility obtained was 83 cm2/V-sec for ITiO deposited at 550 C.
Date: January 1, 2005
Creator: Perkins, J.; Taylor, M.; van Hest, M.; Teplin, C.; Alleman, J.; Dabney, M. et al.
System: The UNT Digital Library
Application of deuteron-deuteron (d-d) fusion neutrons to 40ar/39/ar geochronology (open access)

Application of deuteron-deuteron (d-d) fusion neutrons to 40ar/39/ar geochronology

This report talks about Application of deuteron-deuteron (d-d) fusion neutrons to 40ar/39/ar geochronology
Date: January 1, 2005
Creator: Renne, P.; Knight, K. B.; Nomade, S.; Leung, K. N. & Lou, T. P.
System: The UNT Digital Library
Application of independent component analysis to Fermilab Booster (open access)

Application of independent component analysis to Fermilab Booster

Autocorrelation is applied to analyze sets of finite-sampling data such as the turn-by-turn beam position monitor (BPM) data in an accelerator. This method of data analysis, called the independent component analysis (ICA), is shown to be a powerful beam diagnosis tool for being able to decompose sampled signals into its underlying source signals. They find that the ICA has an advantage over the principle component analysis (PCA) used in the model-independent analysis (MIA) in isolating independent modes. The tolerance of the ICA method to noise in the BPM system is systematically studied. The ICA is applied to analyze the complicated beam motion in a rapid-cycling booster synchrotron at the Fermilab. Difficulties and limitations of the ICA method are also discussed.
Date: January 1, 2005
Creator: Huang, X. B.; Lee, S. Y.; Prebys, E. & Tomlin, R.
System: The UNT Digital Library
Applications of mineral carbonation to geological sequestration of CO2 (open access)

Applications of mineral carbonation to geological sequestration of CO2

Geological sequestration of CO2 is a promising near-term sequestration methodology. However, migration of the CO2 beyond the natural reservoir seals could become problematic, thus the identification of means to enhance the natural seals could prove beneficial. Injection of a mineral reactant slurry could provide a means to enhance the natural reservoir seals by supplying the necessary cations for precipitation of mineral carbonates. The subject study evaluates the merit of several mineral slurry injection strategies by conduct of a series of laboratory-scale CO2 flood tests on whole core samples of the Mt. Simon sandstone from the Illinois Basin.
Date: January 1, 2005
Creator: O'Connor, William K. & Rush, G.E.
System: The UNT Digital Library
Arsenic Sulfide Nanowire Formation on Fused Quartz Surfaces (open access)

Arsenic Sulfide Nanowire Formation on Fused Quartz Surfaces

Arsenic sulfide (AsxSy) nanowires were synthesized by an evaporation-condensation process in evacuated fused quartz ampoules. During the deposition process, a thin, colored film of AsxSy was deposited along the upper, cooler portion of the ampoule. The ampoule was sectioned and the deposited film analyzed using scanning electron microscopy (SEM) to characterize and semi-quantitatively evaluate the microstructural features of the deposited film. A variety of microstructures were observed that ranged from a continuous thin film (warmer portion of the ampoule), to isolated micron- and nano-scale droplets (in the intermediate portion), as well as nanowires (colder portion of the ampoule). Experiments were conducted to evaluate the effects of ampoule cleaning methods (e.g. modify surface chemistry) and quantity of source material on nanowire formation. The evolution of these microstructures in the thin film was determined to be a function of initial pressure, substrate temperature, substrate surface treatment, and initial volume of As2S3 glass. In a set of two experiments where the initial pressure, substrate thermal gradient, and surface treatment were the same, the initial quantity of As2S3 glass per internal ampoule volume was doubled from one test to the other. The results showed that AsxSy nanowires were only formed in the test with …
Date: January 1, 2005
Creator: Olmstead, J.; Riley, B. J.; Johnson, B. R. & Sundaram, S. K.
System: The UNT Digital Library
ASM News Volume 71 Number 9, 2005 (open access)

ASM News Volume 71 Number 9, 2005

Genetic exchanges among prokaryotes, formerly considered only a marginal phenomenon, increasingly are being viewed as profoundly affecting evolution. Indeed, some researchers argue for utterly revamping our concept of microbial speciation and phylogeny by replacing the traditional ''tree'' with a newer ''net'' to account for these horizontal transfers of genes. This conceptual ferment is occurring while molecular biologists reveal how horizontal gene transfers occur even as microbes protect the integrity of their genomes. Other studies reveal the number and diversity and abundance of genetic elements that mediate horizontal gene transfers (HGTs) or facilitate genome rearrangements, deletions, and insertions. Taken together, this information suggests that microbial communities collectively possess a dynamic gene pool, where novel genetic combinations act as a driving force in genomic innovation, compensating individual microbial species for their inability to reproduce sexually. These microbial genomic dynamics can present both environmental threats and promise to humans. One major threat, for example, comes from the spread of antibiotic resistance and virulence genes among pathogenic microbes. Another less-documented issue involves transgenic plants and animals, whose uses are being restricted because of concerns that genes may be transferred to untargeted organisms where they might cause harm. A possible benefit from HGT comes from …
Date: January 1, 2005
Creator: Smets, Tamar Barkay and Barth F.
System: The UNT Digital Library
Aspects of the Coriolis Interaction in U235 (open access)

Aspects of the Coriolis Interaction in U235

We have performed three separate experiments at LBNL's 88-Inch Cyclotron over a period of several years in which {sup 235}U (thick target) was Coulomb-excited. It involved stand-alone experiments with Gammasphere and with the 8PI Spectrometer using {sup 136}Xe beams at 720 MeV, and a CHICO-Gammasphere experiment with an {sup 40}Ar beam at 180 MeV. In addition to extending the known negative-parity bands to high spin, we have assigned levels in some seven positive-parity bands which are in some cases (e.g. [631]1/2, [624]7/2 and [622]5/2) strongly populated by E3 excitation. The CHICO data has been analyzed to extract E2 and E3 matrix elements from the observed yields. Additionally, many E1 and M1 matrix elements could be extracted from the {gamma}-ray branching ratios.
Date: January 1, 2005
Creator: Ward, D.; Clark, R. M.; Cromaz, M.; Deleplanque, M. A.; Diamond, R. M.; Fallon, P. et al.
System: The UNT Digital Library
Beam-beam effects in the Tevatron (open access)

Beam-beam effects in the Tevatron

The Tevatron in Collider Run II (2001-present) is operating with 6 times more bunches, many times higher beam intensities and luminosities than in Run I (1992-1995). Electromagnetic long-range and head-on interactions of high intensity proton and antiproton beams have been significant sources of beam loss and lifetime limitations. We present observations of the beam-beam phenomena in the Tevatron and results of relevant beam studies. We analyze the data and various methods employed in operations, predict the performance for planned luminosity upgrades, and discuss ways to improve it.
Date: January 1, 2005
Creator: Shiltsev, V.; Alexahin, Y.; Lebedev, V.; Lebrun, P.; Moore, R. S.; Sen, T. et al.
System: The UNT Digital Library
Beam-beam simulations of hadron colliders (open access)

Beam-beam simulations of hadron colliders

None
Date: January 1, 2005
Creator: Sen, Tanaji
System: The UNT Digital Library
Biology and management of insect pests in North American intensively managed hardwood forest systems. (open access)

Biology and management of insect pests in North American intensively managed hardwood forest systems.

Annu. Rev. Entomol. 50:1-29. Abstract Increasing demand for wood and wood products is putting stress on traditional forest production areas, leading to long-term economic and environmental concerns. Intensively managed hardwood forest systems (IMHFS), grown using conventional agricultural as well as forestry methods, can help alleviate potential problems in natural forest production areas. Although IMHFS can produce more biomass per hectare per year than natural forests, the ecologically simplified, monocultural systems may greatly increase the crops susceptibility to pests. Species in the genera Populus and Salix comprise the greatest acreage in IMHFS in North America, but other species, including Liquidambar styracifua and Platanus occidentalis, are also important. We discuss life histories, realized and potential damage, and management options for the most economically infuential pests that affect these hardwood species. The substantial inherent challenges associated with pest management in the monocultural environments created by IMHFS are reviewed. Finally, we discuss ways to design IMHFS that may reduce their susceptibility to pests, increase their growth and productivity potential, and create a more sustainable environment.
Date: January 1, 2005
Creator: Coyle, David R.; Nebeker, T., E.; Hart, E., R. & Mattson, W., J.
System: The UNT Digital Library
[Capital Culture Hits the Airwaves] (open access)

[Capital Culture Hits the Airwaves]

Article about Lance Avery Morgan's television feature, "Capital Culture," on Fox 7/KTBC in Austin, Texas.
Date: 2005~
Creator: Aechternacht, Stephen
System: The UNT Digital Library
Causes and prevention of symptom complaints in office buildings:Distilling the experience of indoor environmental qualityinvestigators (open access)

Causes and prevention of symptom complaints in office buildings:Distilling the experience of indoor environmental qualityinvestigators

The goal of this project was to develop empirically based recommendations for practical strategies, suitable for use by those who own, lease, or manage office space, to prevent building-related symptoms in office buildings. Ideas from six experienced building investigators were gathered and prioritized in a multi-day workshop. The top ranked problems identified were, in priority order: excessive building moisture, inadequate outdoor air, dust on indoor surfaces, indoor gases and odors, inadequate thermal control, and inadequate attention by management to indoor environments. The highest priority strategies recommended for preventing building-related symptoms were: managing water at building exteriors, operating ventilation systems per design intent, providing at least minimum ventilation rates, and maintaining indoor temperatures at 72 F {+-} 2{sup o}. Findings in the scientific literature were generally consistent with these recommendations. IEQ investigators showed considerable agreement on the most important causes of symptom complaints in office buildings and the key methods for preventing these problems. Despite the range of climates in which they worked, the investigators agreed that the highest priority prevention strategy was managing water at building exteriors. These recommendations, generally consistent with available research findings, provide useful practical guidelines for those who own, manage or maintain office buildings. The empirical …
Date: January 1, 2005
Creator: Mendell, Mark J.; Diamond, Richard C.; Fisk, William J.; Brennan,Terry; Hathon, Lee; Odom, J. David et al.
System: The UNT Digital Library