Perspective on International PV Challenge & Opportunities for Rural Development (open access)

Perspective on International PV Challenge & Opportunities for Rural Development

International market opportunities for the sale and deployment of photovoltaic (PV) systems abound and will continue to out-pace domestic, grid-connected opportunities for the foreseeable future.
Date: January 1, 2000
Creator: Taylor, R. W.
System: The UNT Digital Library
Innovative Approaches to Development and Ground Testing of Advanced Bimodal Space Power and Propulsion Systems (open access)

Innovative Approaches to Development and Ground Testing of Advanced Bimodal Space Power and Propulsion Systems

The last major development effort for nuclear power and propulsion systems ended in 1993. Currently, there is not an initiative at either the National Aeronautical and Space Administration (NASA) or the U.S. Department of Energy (DOE) that requires the development of new nuclear power and propulsion systems. Studies continue to show nuclear technology as a strong technical candidate to lead the way toward human exploration of adjacent planets or provide power for deep space missions, particularly a 15,000 lbf bimodal nuclear system with 115 kW power capability. The development of nuclear technology for space applications would require technology development in some areas and a major flight qualification program. The last major ground test facility considered for nuclear propulsion qualification was the U.S. Air Force/DOE Space Nuclear Thermal Propulsion Project. Seven years have passed since that effort, and the questions remain the same, how to qualify nuclear power and propulsion systems for future space flight. It can be reasonable assumed that much of the nuclear testing required to qualify a nuclear system for space application will be performed at DOE facilities as demonstrated by the Nuclear Rocket Engine Reactor Experiment (NERVA) and Space Nuclear Thermal Propulsion (SNTP) programs. The nuclear infrastructure …
Date: July 1, 2000
Creator: Hill, Thomas Johnathan; Noble, Cheryl Ann; Noble, C.; Martinell, John Stephen & Borowski, S.
System: The UNT Digital Library
Non-linear Electron Transport Kinetics in Nanocrystalline TiO(2) Based Solar Cells (open access)

Non-linear Electron Transport Kinetics in Nanocrystalline TiO(2) Based Solar Cells

An analytical model describing electron transport in dye-sensitized nanocrystalline TiO(2) solar cells is shown to account for the non-linear dependence of the electron transport rate on the electron concentration. Equations relating the influenece of an exponential distribtuion of surface states to electron transport are derived and verified by intensity-modulated photocurrent spectroscopy measurements. A slope of 69 meV is inferred for the surface-state distribution curve.
Date: January 1, 2000
Creator: van de Lagemaat, J. & Frank, A. J.
System: The UNT Digital Library
Preliminary Investigations of Outdoor Meteorological Broadband and Spectral Conditions for Evaluating Photovoltaic Modules and Systems (open access)

Preliminary Investigations of Outdoor Meteorological Broadband and Spectral Conditions for Evaluating Photovoltaic Modules and Systems

Historically, flat-plate photovoltaic (PV) modules have been rated at "peak-output" for power generated under Standard; Reporting Conditions (SRC) of 1000 Watts per square meter W/m2 global irradiance at a standard temperature (25degC) and reference spectral distribution. We examine the direct-normal irradiance, spectral distribution, ambient temperature, and wind speed to be used for evaluating flatplate and concentrator module performance. Our study is based upon the 30-year U.S. National Solar Radiation Data Base for conditions observed when the global irradiance on a 2-axis-tracked surface is 1000 W/m2. Results show commonly-used values for concentrator testing of 850 W/m2 for direct-normal irradiance and 20degC for ambient temperature are appropriate. Wind speed should be increased from 1 m/s to a more frequently observed 4 m/s. Differences between the reference direct-normal spectrum and spectra measured at three sites when broadband direct-normal irradiance and global-normal irradiance are near SRC irradiances suggest revisions to the reference spectra may be needed.
Date: January 1, 2000
Creator: Myers, D. R.; Kurtz, S. R.; Whitaker, C. & Townsend, T.
System: The UNT Digital Library
Wireless Handheld Scanners Integrated with Waste Tracking (open access)

Wireless Handheld Scanners Integrated with Waste Tracking

The US Department of Energy (DOE) Idaho National Engineering and Environmental Laboratory (INEEL) has embraced mobile wireless technology to help the disposition of hazardous and mixed radiological waste. The following paper describes one application the INEEL developed to increase the data accuracy and near-real time reporting requirements for waste management. With the continuous operational demands at the "site", it was difficult to sustain an accurate, up-to-date database required for regulatory compliance audits and reporting. Incorporating wireless mobile technology, the INEEL was able to increase the accuracy while reducing the data delay times previously encountered. Installation issues prolonged the project along with obstacles encountered with operations personnel. However, the success of this project was found in persistence and management support as well as the technology itself. Future wireless, mobile computing will continue at the INEEL for years to come based on a successful project that was able to integrate new technology to an existing waste management system with proven, increased data accuracy.
Date: July 1, 2000
Creator: Anderson, Robert Stephen
System: The UNT Digital Library
Critical Function Models for Operation of the International Space Station (open access)

Critical Function Models for Operation of the International Space Station

Long duration and exploration class space missions will place new requirements on human performance when compared to current space shuttle missions. Specifically, assembly and operation of the International Space Station (ISS) will place significant new demands on the crew. For example, maintenance of systems that provide habitability will become an ongoing activity for the international flight crews. Tasks for maintaining space station habitability will need to be integrated with tasks associated with scientific research. In addition, tasks and resources will need to be prioritized and allocated dynamically in response to changing operational conditions and unplanned system breakdowns. This paper describes an ongoing program to develop a habitability index (HI) for space operations based on the critical function approach. This pilot project focuses on adaptation of the critical function approach to develop a habitability index specifically tailored for space operations. Further work will then be needed to expand and validate the habitability index for application in the ISS operational environment.
Date: November 1, 2000
Creator: Nelson, William Roy & Bagian, T. M.
System: The UNT Digital Library
Cloud Optical Depths and Liquid Water Paths at the NSA CART (open access)

Cloud Optical Depths and Liquid Water Paths at the NSA CART

Cloud optical depths have been measured using multifilter rotating shadowband radiometers (MFRSRs) at Barrow and Atqasuk, and liquid water paths have been measured at Barrow using a microwave radiometer (MWR) during the warm season (June-September) in 1999. Comparisons have been made between these quantities and the corresponding ones determined from the ECMWF GCM. Hour-by-hour comparisons of cloud optical depths show considerable scatter. The scatter is reduced, but is still substantial, when the averaging period is increased to ''daily'' averages, i.e., the time period each day over which the MFRSR can make measurements. This period varied between 18 hours in June and 6 hours in September. Preliminary results indicate that, for measured cloud optical depths less than approximately 25, the ECMWF has a low bias in its predictions, consistent with a low bias in predicted liquid water path. Based on a more limited set of data, the optical depths at Atqasuk were found to be generally lower than those at Barrow, a trend at least qualitatively captured by the ECMWF model. Analyses to identify the cause of the biases and the considerable scatter in the predictions are continuing.
Date: March 14, 2000
Creator: Doran, J. C.; Barnard, James C.; Zhong, Shiyuan & Jakob, C J.
System: The UNT Digital Library
Anarchy and hierarchy (open access)

Anarchy and hierarchy

We advocate a new approach to study models of fermion massesand mixings, namely anarchy proposed in hep-ph/9911341. In this approach,we scan the O(1) coefficients randomly. We argue that this is the correctapproach when the fundamental theory is sufficiently complicated.Assuming there is no physical distinction among three generations ofneutrinos, the probability distributions in MNS mixing angles can bepredicted independent of the choice of the measure. This is because themixing angles are distributed according to the Haar measure of the Liegroups whose elements diagonalize the mass matrices. The near-maximalmixings, as observed in the atmospheric neutrino data and as required inthe LMA solution to the solar neutrino problem, are highly probable. Asmall hierarchy between the Delta m2 for the atmospheric and the solarneutrinos is obtained very easily; the complex seesaw case gives ahierarchy of a factor of 20 as the most probable one, even though thisconclusion is more measure-dependent. U_e3 has to be just below thecurrent limit from the CHOOZ experiment. The CP-violating parameter sindelta is preferred to be maximal. We present a simple SU(5)-likeextension of anarchy to the charged-lepton and quark sectors which workswell phenomenologically.
Date: September 14, 2000
Creator: Haba, Naoyuki & Murayama, Hitoshi
System: The UNT Digital Library
Keys to Successful D&D Technology Deployments at the INEEL (open access)

Keys to Successful D&D Technology Deployments at the INEEL

Seven improved decontamination and decommissioning (D&D) technologies were successfully deployed at the Idaho National Engineering and Environmental Laboratory (INEEL) during the Accelerated Site Technology Deployment (ASTD) Integrated Decontamination and Decommissioning (ID&D) project. The use of these improved technologies saved the INEEL $462K in fiscal year 1999, and is projected to save about $14M over the next ten years. Since deploying new technologies on D&D projects shows great potential for cost-savings, factors that led to successful deployment have been documented. These factors are described here as they apply to the seven deployments at the INEEL to assist with deployments at other DOE sites.
Date: April 1, 2000
Creator: Smith, Agatha Marie; Meservey, Richard Harlan & Tripp, Julia Lynn
System: The UNT Digital Library
A Novel Synthesis of Polyesters Containing Hexa-(tert-butylhydroquinone)cyclotriphosphazene (open access)

A Novel Synthesis of Polyesters Containing Hexa-(tert-butylhydroquinone)cyclotriphosphazene

The majority of polyphosphazene material research has concentrated on the linear polymer configuration. However, this represents only one of three potential backbone configurations for phosphazenes. Linear polymers are formed either directly from phosphorus and nitrogen containing precursors or from the ring opening polymerization of hexachlorocyclotriphosphazene. Two other backbone structures can be formed from hexachlorocyclotriphosphazene cyclolinear and cyclomatrix. Cyclolinear are the least studied due to synthetic difficulty. Cyclomatrix polymers represent a more facile method for forming non-linear phosphazenes.
Date: March 1, 2000
Creator: Stewart, Frederick Forrest; Luther, Thomas Alan; Harrup, Mason Kurt & Lash, Robert Paul
System: The UNT Digital Library
Highly Efficient 32.3% Monolithic GaInP/GaAs/Ge Triple Junction Concentrator Solar Cells (open access)

Highly Efficient 32.3% Monolithic GaInP/GaAs/Ge Triple Junction Concentrator Solar Cells

Based on recent cell improvements for space applications, multijunction cells apear to be ideal candidates for high efficiency, cost effective, PV concentrator systems.
Date: January 1, 2000
Creator: Cotal, H. L.; Lillington, D. R.; Ermer, J. H.; King, R. R.; Karam, N. H.; Kurtz, S. R. et al.
System: The UNT Digital Library
Commissioning of a Higher Harmonic RF System for the Advanced Light Source (open access)

Commissioning of a Higher Harmonic RF System for the Advanced Light Source

We report on the commissioning of a higher harmonic RF system designed to improve the Touschek lifetime of the Advanced Light Source. In our best results, we have achieved over a factor of two increase in the beam lifetime. Transient beam loading of the harmonic cavities by unequal fill patterns presents the greatest limitations on lifetime improvement. We also describe several interesting effects of the harmonic cavities on the operation of the longitudinal and transverse multibunch feedback systems.
Date: March 31, 2000
Creator: Byrd, John M.; De Santis, Stefano; Georgsson, Mattias; Stover,G.; Fox, John D. & Teytelman, Dmitry
System: The UNT Digital Library
Effect of Radiation on Spinel Ceramics for Permanent Containers for Nuclear Waste Transportation and Storage. (open access)

Effect of Radiation on Spinel Ceramics for Permanent Containers for Nuclear Waste Transportation and Storage.

None
Date: April 30, 2000
Creator: Adams, J.; Cowgill, M.; Moskowitz, P. & Rokhvarger, A.
System: The UNT Digital Library
Carbon dioxide sequestration by direct aqueous mineral carbonation (open access)

Carbon dioxide sequestration by direct aqueous mineral carbonation

Carbon dioxide sequestration by an ex-situ, direct aqueous mineral carbonation process has been investigated over the past two years. This process was conceived to minimize the steps in the conversion of gaseous CO2 to a stable solid. This meant combining two separate reactions, mineral dissolution and carbonate precipitation, into a single unit operation. It was recognized that the conditions favorable for one of these reactions could be detrimental to the other. However, the benefits for a combined aqueous process, in process efficiency and ultimately economics, justified the investigation. The process utilizes a slurry of water, dissolved CO2, and a magnesium silicate mineral, such as olivine [forsterite end member (Mg2SiO4)], or serpentine [Mg3Si2O5(OH)4]. These minerals were selected as the reactants of choice for two reasons: (1) significant abundance in nature; and (2) high molar ratio of the alkaline earth oxides (CaO, MgO) within the minerals. Because it is the alkaline earth oxide that combines with CO2 to form the solid carbonate, those minerals with the highest ratio of these oxides are most favored. Optimum results have been achieved using heat pretreated serpentine feed material, sodium bicarbonate and sodium chloride additions to the solution, and high partial pressure of CO2 (PCO2). Specific …
Date: January 1, 2000
Creator: O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Walters, Richard P. & Turner, Paul C.
System: The UNT Digital Library
Nitrogen-Induced Evolution of GaAs1-xNx Studied by Ballistic Electron Emission Spectroscopy (open access)

Nitrogen-Induced Evolution of GaAs1-xNx Studied by Ballistic Electron Emission Spectroscopy

Giant bandgap reduction of dilute GaAs1-xNx with nitrogen incorporation makes this material to be very attractive for conversion efficiency increase in multijunction, high efficiency solar cells.
Date: January 1, 2000
Creator: Narayanamurti, V.; Kozhevnikov, M.; Xin, H. P.; Tu, C. W.; Mascarenhas, A. & Zhang, Y.
System: The UNT Digital Library
Heat Transfer Enhancement for Finned-tube Heat Exchangers with Winglets (open access)

Heat Transfer Enhancement for Finned-tube Heat Exchangers with Winglets

This paper presents the results of an experimental study of forced convection heat transfer in a narrow rectangular duct fitted with a circular tube and/or a delta-winglet pair. The duct was designed to simulate a single passage in a fin-tube heat exchanger. Heat transfer measurements were obtained using a transient technique in which a heated airflow is suddenly introduced to the test section. High-resolution local fin-surface temperature distributions were obtained at several times after initiation of the transient using an imaging infrared camera. Corresponding local fin-surface heat transfer coefficient distributions were then calculated from a locally applied one-dimensional semi-infinite inverse heat conduction model. Heat transfer results were obtained over an airflow rate ranging from 1.51 x 10-3 to 14.0 x 10-3 kg/s. These flow rates correspond to a duct-height Reynolds number range of 670 – 6300 with a duct height of 1.106 cm and a duct width-toheight ratio, W/H, of 11.25. The test cylinder was sized such that the diameter-to-duct height ratio, D/H is 5. Results presented in this paper reveal visual and quantitative details of local fin-surface heat transfer distributions in the vicinity of a circular tube, a delta-winglet pair, and a combination of a circular tube and a …
Date: November 1, 2000
Creator: O'Brien, James Edward & Sohal, Manohar Singh
System: The UNT Digital Library
A PWR Thorium Pin Cell Burnup Benchmark (open access)

A PWR Thorium Pin Cell Burnup Benchmark

As part of work to evaluate the potential benefits of using thorium in LWR fuel, a thorium fueled benchmark comparison was made in this study between state-of-the-art codes, MOCUP (MCNP4B + ORIGEN2), and CASMO-4 for burnup calculations. The MOCUP runs were done individually at MIT and INEEL, using the same model but with some differences in techniques and cross section libraries. Eigenvalue and isotope concentrations were compared on a PWR pin cell model up to high burnup. The eigenvalue comparison as a function of burnup is good: the maximum difference is within 2% and the average absolute difference less than 1%. The isotope concentration comparisons are better than a set of MOX fuel benchmarks and comparable to a set of uranium fuel benchmarks reported in the literature. The actinide and fission product data sources used in the MOCUP burnup calculations for a typical thorium fuel are documented. Reasons for code vs code differences are analyzed and discussed.
Date: May 1, 2000
Creator: Weaver, Kevan Dean; Zhao, X.; Pilat, E. E & Hejzlar, P.
System: The UNT Digital Library
Residual Stress Determination from a Laser-Based Curvature Measurement (open access)

Residual Stress Determination from a Laser-Based Curvature Measurement

Thermally sprayed coating characteristics and mechanical properties are in part a result of the residual stress developed during the fabrication process. The total stress state in a coating/substrate is comprised of the quench stress and the coefficient of thermal expansion (CTE) mismatch stress. The quench stress is developed when molten particles impact the substrate and rapidly cool and solidify. The CTE mismatch stress results from a large difference in the thermal expansion coefficients of the coating and substrate material. It comes into effect when the substrate/coating combination cools from the equilibrated deposit temperature to room temperature. This paper describes a laser-based technique for measuring the curvature of a coated substrate and the analysis required to determine residual stress from curvature measurements. Quench stresses were determined by heating the specimen back to the deposit temperature thus removing the CTE mismatch stress. By subtracting the quench stress from the total residual stress at room temperature, the CTE mismatch stress was estimated. Residual stress measurements for thick (>1mm) spinel coatings with a Ni-Al bond coat on 304 stainless steel substrates were made. It was determined that a significant portion of the residual stress results from the quenching stress of the bond coat and …
Date: May 1, 2000
Creator: Swank, William David; Gavalya, Rick Allen; Wright, Julie Knibloe & Wright, Richard Neil
System: The UNT Digital Library
Local Structure of CuIn3Se5 (open access)

Local Structure of CuIn3Se5

The results of a detailed EXAFS study of the Cu-K, In-K, and Se-K edges CuIn3Se5 are reported. The Cu and In first nearest neighbor local structures were found to be almost identical to those in CuInSe2.
Date: January 1, 2000
Creator: Chang, C. H.; Wei, S. H.; Leyarovska, N.; Johnson, J. W.; Zhang, S. B.; Stanbery, B. J. et al.
System: The UNT Digital Library
Transition From in-Plane to Out-of-Plane Azimuthal Enhancement in Au+Au Collisions (open access)

Transition From in-Plane to Out-of-Plane Azimuthal Enhancement in Au+Au Collisions

The incident energy at which the azimuthal distributions in semi-central heavy ion collisions change from in-plane to out-of-plane enhancement--E{sub tran} is studied as a function of mass of emitted particles, their transverse momentum and centrality for Au+Au collisions. The analysis is performed in a reference frame rotated with the sidewards flow angle ({Theta}{sub flow}) relative to the beam axis. A systematic decrease of E{sub tran} as function of mass of the reaction products, their transverse momentum and collision centrality is evidenced. The predictions of a microscopic transport model (IQMD) are compared with the experimental results.
Date: August 9, 2000
Creator: Andronic, A.; Stoicea, G.; Petrovici, M.; Simion, V.; Crochet, P.; Alard, J. P. et al.
System: The UNT Digital Library
Radioactive Material Transportation Requirements for the Department of Energy (open access)

Radioactive Material Transportation Requirements for the Department of Energy

The Department of Energy (DOE) created the National Transportation Program (NTP) whose goal is to ensure the availability of safe, efficient, and timely transportation of DOE materials. The Integration and Planning Group of the NTP, assisted by Global Technologies Incorporated (GTI), was tasked to identify requirements associated with the transport of DOE Environmental Management (EM) radiological waste/material. A systems engineering approach was used to identify source documents, extract requirements, perform a functional analysis, and set up a transportation requirements management database in RDD-100. Functions and requirements for transporting the following DOE radioactive waste/material are contained in the database: high level radioactive waste (HLW), low-level radioactive waste (LLW), mixed low-level radioactive waste (MLLW), nuclear materials (NM), spent nuclear fuel (SNF), and transuranic waste (TRU waste). The requirements will be used in the development of standard transportation protocols for DOE shipping. The protocols will then be combined into a DOE Transportation Program Management Guide, which will be used to standardize DOE transportation processes.
Date: July 1, 2000
Creator: John, Mark Earl; Fawcett, Ricky Lee & Bolander, Thane Weston
System: The UNT Digital Library
Implementation of the INEEL Safety Analyst Training Standard (open access)

Implementation of the INEEL Safety Analyst Training Standard

The Idaho Nuclear Technology and Engineering Center (INTEC) safety analysis units at the Idaho National Engineering and Environmental Laboratory (INEEL) are in the process of implementing the recently issued INEEL Safety Analyst Training Standard (STD-1107). Safety analyst training and qualifications are integral to the development and maintenance of core safety analysis capabilities. The INEEL Safety Analyst Training Standard (STD-1107) was developed directly from EFCOG Training Subgroup draft safety analyst training plan template, but has been adapted to the needs and requirements of the INEEL safety analysis community. The implementation of this Safety Analyst Training Standard is part of the Integrated Safety Management System (ISMS) Phase II Implementation currently underway at the INEEL. The objective of this paper is to discuss (1) the INEEL Safety Analyst Training Standard, (2) the development of the safety analyst individual training plans, (3) the implementation issues encountered during this initial phase of implementation, (4) the solutions developed, and (5) the implementation activities remaining to be completed.
Date: May 1, 2000
Creator: Hochhalter, E Eugene
System: The UNT Digital Library
New capabilities in the HENP grand challenge storage access systemand its application at RHIC (open access)

New capabilities in the HENP grand challenge storage access systemand its application at RHIC

The High Energy and Nuclear Physics Data Access GrandChallenge project has developed an optimizing storage access softwaresystem that was prototyped at RHIC. It is currently undergoingintegration with the STAR experiment in preparation for data taking thatstarts in mid-2000. The behavior and lessons learned in the RHIC MockData Challenge exercises are described as well as the observedperformance under conditions designed to characterize scalability. Up to250 simultaneous queries were tested and up to 10 million events across 7event components were involved in these queries. The system coordinatesthe staging of "bundles" of files from the HPSS tape system, so that allthe needed components of each event are in disk cache when accessed bythe application software. The caching policy algorithm for thecoordinated bundle staging is described in the paper. The initialprototype implementation interfaced to the Objectivity/DB. In this latestversion, it evolved to work with arbitrary files and use CORBA interfacesto the tag database and file catalog services. The interface to the tagdatabase and the MySQL-based file catalog services used by STAR aredescribed along with the planned usage scenarios.
Date: April 25, 2000
Creator: Bernardo, L.; Gibbard, B.; Malon, D.; Nordberg, H.; Olson, D.; Porter, R. et al.
System: The UNT Digital Library
Carbon dioxide sequestration by direct mineral carbonation with carbonic acid (open access)

Carbon dioxide sequestration by direct mineral carbonation with carbonic acid

The Albany Research Center (ARC) of the U.S. Dept. of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. Other participants in this Program include the Los Alamos National Laboratory, Arizona State University, Science Applications International Corporation, and the DOE National Energy Technology Laboratory. The ARC tests have focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC utilizes a slurry of water mixed with a magnesium silicate mineral, olivine [forsterite end member (Mg2SiO4)], or serpentine [Mg3Si2O5(OH)4]. This slurry is reacted with supercritical carbon dioxide (CO2) to produce magnesite (MgCO3). The CO2 is dissolved in water to form carbonic acid (H2CO3), which dissociates to H+ and HCO3 -. The H+ reacts with the mineral, liberating Mg2+ cations which react with the bicarbonate to form the solid carbonate. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and for this reason, these results may also be applicable to in-situ geological sequestration regimes. Results of the baseline tests, conducted on ground products of the natural minerals, have been encouraging. Tests conducted …
Date: January 1, 2000
Creator: O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Walters, Richard P. & Turner, Paul C.
System: The UNT Digital Library