Resource Type

Indium dopant/defect complexes in lightly-doped ceria (open access)

Indium dopant/defect complexes in lightly-doped ceria

Four well-defined indium-dopant/lattice-defect complexes and the non-complexed substitutional indium dopant have been observed by perturbed angular correlation (PAC) spectroscopy in cerium oxide. PAC is a nuclear hyperfine experimental method that detects interactions between a radioactive probe nucleus and nearby atoms. The magnitude and symmetry of those interactions provide a signature for the electromagnetic fields at the probe nucleus. These fields are produced by the arrangement of charges and magnetic moments in the near environment of the probe, so they provide a means of identifying defect structures.
Date: December 31, 1991
Creator: Wang, Ruiping; Gardner, J. A.; Evenson, W. E. & Sommers, J. A.
System: The UNT Digital Library
Photovoltaics as a worldwide energy source (open access)

Photovoltaics as a worldwide energy source

Photovoltaic energy systems have historically been treated as a bulk power generation source for the future. However, utilities and other agencies involved with electrification throughout the world are beginning to find photovoltaics a least-cost option to meet specific loads both for themselves and their customers, in both off-grid and grid-connected applications. These expanding markets offer the potential of hundreds of megawatts of sales in the coming decade, but a strategy addressing both industrial growth and user acceptance is necessary to capitalize on this opportunity. 11 refs.
Date: December 31, 1991
Creator: Jones, G. J.
System: The UNT Digital Library
Quantification and reduction of the uncertainty in mass balance models by Monte Carlo analysis of prior data (open access)

Quantification and reduction of the uncertainty in mass balance models by Monte Carlo analysis of prior data

The general objective of this workshop is to investigate and discuss methods by which uncertainties in mass balance models for toxics in the Great Lakes may be reduced. As described by the workshop prospectus, this paper is focused on problems of reducing (and quantifying) uncertainty as they relate to ``in situ field observations/system response measurements for the establishment of initial conditions, boundary conditions, calibration/confirmation data sets, and model post-audit data sets.`` I have taken this description to refer not only to the evaluation of uncertainty in the field observations themselves, but also to the uncertainty associated the analyses of in situ observations as they interact in the overall modeling process. Thus, I will be concerned here with quantification and reduction of uncertainty both (1) as they may be applied to descriptions of the system that is being modeled and (2) as they may be associated with model simulations.
Date: December 31, 1991
Creator: Lesht, B. M.
System: The UNT Digital Library
Second International Symposium on the Biogeochemistry of Model Estuaries: Estuarine processes in global change. Final report (open access)

Second International Symposium on the Biogeochemistry of Model Estuaries: Estuarine processes in global change. Final report

This report summarizes estuary events discussed at the symposium on biogeochemistry. Topics include; sedimentation, salinity, inputs and outputs of the estuary, effects of global change, and the need for effective sampling and modeling of estuaries.
Date: December 31, 1991
Creator: Windom, Herbert L.
System: The UNT Digital Library
Characterization and utilization of hydrotreated products produced from the Whiterocks (Utah) tar sand bitumen-derived liquid (open access)

Characterization and utilization of hydrotreated products produced from the Whiterocks (Utah) tar sand bitumen-derived liquid

The bitumen-derived liquid produced in a 4-inch diameter fluidized-bed reactor from the mined and crushed ore from the Whiterocks tar sand deposit has been hydrotreated in a fixed-bed reactor. The purpose was to determine the extent of upgrading as a function of process operating variable. A sulfided nickel-molybendum on alumina hydrodenitrogenation catalyst was used in all experiments. Moderately severe operating conditions were employed; that is, high reaction temperature (617--680 K) high reactor pressure (11.0--17.1 MPa) and low liquid feed rate (0.18--0.77 HSV); to achieve the desired reduction in heteroatom content. Detailed chemical structures of the bitumen-derived liquid feedstock and the hydrotreated total liquid products were determined by high resolution gas chromatography - mass spectrometry analyses. The compounds identified in the native bitumen included isoprenoids; bicyclic, tricycle, and tetracyclic terpenoids; steranes; hopanes; and perhydro-{beta}-carotenes. In addition, normal and branched alkanes and alkenes and partially dehydrogenated hydroaromatics were identified in the bitumen-derived liquid. The dominant pyrolysis reactions were: (1) the dealkylation of long alkyl side chains to form {alpha} - and isoolefins; and (2) the cleavage of alkyl chains linking aromatic and hydroaromatic clusters. Olefinic bonds were not observed in the hydrotreated product and monoaromatic hydrocarbons were the predominant aromatic species. The …
Date: December 31, 1991
Creator: Tsai, C. H.; Longstaff, D. C.; Deo, M. D.; Hanson, F. V. & Oblad, A. G.
System: The UNT Digital Library
Second international symposium on the biogeochemistry of model estuaries: Estuarine processes in global change (open access)

Second international symposium on the biogeochemistry of model estuaries: Estuarine processes in global change

This report consists of abstracts of papers presented at the symposium of Biogeochemistry. The main topics discussed at the meeting are; nutrient and mineral cycling, trace element distribution, sources and sinks of estuaries, sedimentation, importance of organic matter, and other biogeochemical processes of estuaries.
Date: December 31, 1991
Creator: unknown
System: The UNT Digital Library
S/EV 91: Solar and electric vehicle symposium, car and trade show. Proceedings (open access)

S/EV 91: Solar and electric vehicle symposium, car and trade show. Proceedings

These proceedings cover the fundamentals of electric vehicles. Papers on the design, testing and performance of the power supplies, drive trains, and bodies of solar and non-solar powered electric vehicles are presented. Results from demonstrations and races are described. Public policy on the economics and environmental impacts of using electric powered vehicles is also presented.
Date: December 31, 1991
Creator: unknown
System: The UNT Digital Library
National conference on integrated resource planning: Proceedings (open access)

National conference on integrated resource planning: Proceedings

Until recently, state regulators have focused most of their attention on the development of least-cost or integrated resource planning (IRP) processes for electric utilities. A number of commissions are beginning to scrutinize the planning processes of local gas distribution companies (LDCs) because of the increased control that LDCs have over their purchased gas costs (as well as the associated risks) and because of questions surrounding the role and potential of gas end-use efficiency options. Traditionally, resource planning (LDCs) has concentrated on options for purchasing and storing gas. Integrated resource planning involves the creation of a process in which supply-side and demand-side options are integrated to create a resource mix that reliably satisfies customers` short-term and long-term energy service needs at the lowest cost. As applied to gas utilities, an integrated resource plan seeks to balance cost and reliability, and should not be interpreted simply as the search for lowest commodity costs. The National Association of Regulatory Utility Commissioners` (NARUC) Energy Conservation committee asked Lawrence Berkeley Laboratory (LBL) to survey state PUCs to determine the extent to which they have undertaken least cost planning for gas utilities. The survey included the following topics: status of state PUC least-cost planning regulations and …
Date: December 31, 1991
Creator: unknown
System: The UNT Digital Library
Environmental remediation 1991: ``Cleaning up the environment for the 21st Century``. Proceedings (open access)

Environmental remediation 1991: ``Cleaning up the environment for the 21st Century``. Proceedings

This report presents discussions given at a conference on environmental remediation, September 8--11, Pasco, Washington. Topics include: public confidence; education; in-situ remediation; Hanford tank operations; risk assessments; field experiences; standards; site characterization and monitoring; technology discussions; regulatory issues; compliance; and the UMTRA project. Individual projects are processed separately for the data bases.
Date: December 31, 1991
Creator: Wood, D. E.
System: The UNT Digital Library