A novel approach to highly dispersing catalytic materials in coal for gasification. Ninth quarterly report, October 1, 1991--December 31, 1991 (open access)

A novel approach to highly dispersing catalytic materials in coal for gasification. Ninth quarterly report, October 1, 1991--December 31, 1991

This project seeks to develop a technique, based on coal surface properties, for highly dispersing catalysts in coal for gasification and to investigate the potential of using potassium carbonate and calcium acetate mixtures as catalysts for coal gasification. The lower cost and higher catalytic activity of the latter compound will produce economic benefits by reducing the amount of K{sub 2}CO{sub 3} required for high coal char reactivities. As was shown in previous reports, coal loading with potassium or calcium at different pHs produced CO{sub 2} gasification activities which increased in the order pH 6 > pH 10 {much_gt} pH 1. The current report shows that a similar trend was obtained when calcium and potassium were simultaneously loaded and char reaction times were less than about 75 min. Beyond this time, the coal impregnated with catalyst at pH 1 became more reactive, reaching 100% conversion after 1.5h. X-ray diffraction analysis suggest that the catalysts are well dispersed around pH 1 and 6 whereas reduced dispersion as obtained at pH 10. The reactivities are independent of the surface areas of the coals.
Date: February 10, 1992
Creator: Abotsi, G. M. K. & Bota, K. B.
Object Type: Report
System: The UNT Digital Library
A novel approach to highly dispersing catalytic materials in coal for gasification (open access)

A novel approach to highly dispersing catalytic materials in coal for gasification

This project seeks to develop a technique, based on coal surface properties, for highly dispersing catalysts in coal for gasification and to investigate the potential of using potassium carbonate and calcium acetate mixtures as catalysts for coal gasification. The lower cost and higher catalytic activity of the latter compound will produce economic benefits by reducing the amount of K{sub 2}CO{sub 3} required for high coal char reactivities. As was shown in previous reports, coal loading with potassium or calcium at different pHs produced CO{sub 2} gasification activities which increased in the order pH 6 > pH 10 {much gt} pH 1. The current report shows that a similar trend was obtained when calcium and potassium were simultaneously loaded and char reaction times were less than about 75 min. Beyond this time, the coal impregnated with catalyst at pH 1 became more reactive, reaching 100% conversion after 1.5h. X-ray diffraction analysis suggest that the catalysts are well dispersed around pH 1 and 6 whereas reduced dispersion as obtained at pH 10. The reactivities are independent of the surface areas of the coals.
Date: February 10, 1992
Creator: Abotsi, G.M.K. & Bota, K.B.
Object Type: Report
System: The UNT Digital Library
Preliminary Safety Evaluation of the Sodium Reactor Experiment (open access)

Preliminary Safety Evaluation of the Sodium Reactor Experiment

A description is given of the Sodium Reactor Experiment (SRE) facilities and program of objectives. The hazards associated with equipment failures and malfunctions, personnel errors, natural causes, and operation are evaluated (C.J.G.)
Date: February 19, 1954
Creator: Abott, W. E.
Object Type: Report
System: The UNT Digital Library
Determination of the Parity of the Neutral Pion via the Four-Electron Decay (open access)

Determination of the Parity of the Neutral Pion via the Four-Electron Decay

We present a new determination of the parity of the neutral pion via the double Dalitz decay {pi}{sup 0} {yields} e{sup +}e{sup -}e{sup +}e{sup -}. Our sample, which consists of 30 511 candidate decays, was collected from K{sub L} {yields} {pi}{sup 0}{pi}{sup 0}{pi}{sup 0} decays in flight at the KTeV-E799 experiment at Fermi National Accelerator Laboratory. We confirm the negative {pi}{sup 0} parity, and place a limit on scalar contributions to the {pi}{sup 0} {yields} e{sup +}e{sup -}e{sup +}e{sup -} decay amplitude of less than 3.3% assuming CPT conservation. The {pi}{sup 0}{gamma}*{gamma}* form factor is well described by a momentum-dependent model with a slope parameter fit to the final state phase space distribution. Additionally, we have measured the branching ratio of this mode to be B({pi}{sup 0} {yields} e{sup +}e{sup -}e{sup +}e{sup -}) = (3.26 {+-} 0.18) x 10{sup -5}.
Date: February 1, 2008
Creator: Abouzaid, E.; Arenton, M.; Barker, A. R.; Bellantoni, L.; Blucher, E.; Bock, G. J. et al.
Object Type: Article
System: The UNT Digital Library
Measurement of the Depth of Maximum of Extensive Air Showers above 10^18 eV (open access)

Measurement of the Depth of Maximum of Extensive Air Showers above 10^18 eV

We describe the measurement of the depth of maximum, X{sub max}, of the longitudinal development of air showers induced by cosmic rays. Almost 4000 events above 10{sup 18} eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106{sub -21}{sup +35}) g/cm{sup 2}/decade below 10{sup 18.24 {+-} 0.05}eV, and (24 {+-} 3) g/cm{sup 2}/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm{sup 2}. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.
Date: February 1, 2010
Creator: Abraham, J.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Allard, D.; Allekotte, I. et al.
Object Type: Article
System: The UNT Digital Library
The Reaction of Glass During Gamma Irradiation in a Saturated Tuff Environment: Part 3, Long-Term Experiments at 1 X 10{Sup 4}Rad/Hour (open access)

The Reaction of Glass During Gamma Irradiation in a Saturated Tuff Environment: Part 3, Long-Term Experiments at 1 X 10{Sup 4}Rad/Hour

Savannah River Laboratory 165 type glass was leached with equilibrated J-13 groundwater at 90{degree}C for times up to 182 days. These experiments were performed as part of an effort by the Nevada Nuclear Waste Storage Investigations Project to assess the importance of radiation effects on repository performance and waste glass corrosion. The gamma radiation field used in this work was 1. 0 +- 0.2 x 10{sup 4} rad/h. Glass dissolution is notably incongruent throughout the entire experimental periods and normalized releases follow the sequence Li {ge} Na {ge} B {approx_equal} U {ge} Si. The normalized leach rates of these elements, as well as the measured growth rates of the reaction layers, decreased with time. The only significant variation observed in the abundance of anions is the systematic decrease in NO{sub 3}/sup {minus}//NO{sub 2}/sup {minus}/ ratio from the starting EJ-13 groundwater to the EJ-13 blank experiments to the tuff- and glass-containing experiments. A leaching model that is consistent with the observed solution data and depth profiles is presented. The applicability and limitation of the present results in predicting the actual interactions that may occur in the NNWSI repository are discussed. 35 refs., 30 figs., 12 tabs.
Date: February 1, 1988
Creator: Abrajano, T. A., Jr.; Bates, J. K.; Gerding, T. J. & Ebert, W. L.
Object Type: Report
System: The UNT Digital Library
Improved Performance in CuInSe2 and Surface-Modified CuGaSe2 Solar Cells (open access)

Improved Performance in CuInSe2 and Surface-Modified CuGaSe2 Solar Cells

In this paper, we present an update and review on the progress made in the development of low-bandgap CuInSe2 (CIS) and wide-bandgap CuGaSe2 (CGS) solar cells. Our research project is a primarily concerned with the optimization of the bottom and top cells of the tandem solar cell. This past year, we established new record total-area efficiencies of 15.0% and 10.2% for CIS and surface-modified CGS solar cells, respectively. These achievements were possible by modifying the growth process for CIS and CGS absorbers. We attempt to modify the surface region of the CGS absorber to be CIGS-like in composition. We also have designed a mechanical-stacked tandem solar cell where the 15% CIS cell serves as the bottom cell. The NREL-confirmed total-area efficiency for this tandem device is 15.31%.
Date: February 1, 2005
Creator: AbuShama, J.; Noufi, R.; Johnston, S.; Ward, S. & Wu, X.
Object Type: Article
System: The UNT Digital Library
EARLY ENTRANCE COPRODUCTION PLANT (open access)

EARLY ENTRANCE COPRODUCTION PLANT

The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or other carbonaceous feedstocks. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site and to develop a Research, Development, and Testing Plan (RD and T) for implementation in Phase II. The objective of Phase II is to implement the RD and T as outlined in the Phase I RD and T Plan to enhance the development and commercial acceptance of coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The project will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and/or other carbonaceous feedstocks. The objective of Phase III is to develop an engineering design package and a financing plan …
Date: February 15, 2001
Creator: Abughazaleh, John S.; Ahmed, Mushtaq; Anand, Ashok; Anderson, John H.; Benham, Charles; Brent, Fred D. et al.
Object Type: Report
System: The UNT Digital Library
Measurement of sigma p anti-p --> Z . Br (Z --> 2tau) in p anti-p collisions at s**(1/2) = 1.96 TeV (open access)

Measurement of sigma p anti-p --> Z . Br (Z --> 2tau) in p anti-p collisions at s**(1/2) = 1.96 TeV

We present a measurement of the inclusive production cross-section for Z bosons decaying to tau leptons in p{bar p} collisions at {radical}s = 1.96 TeV. We use a channel with one hadronically-decaying and one electronically-decaying tau. This measurement is based on 350 pb{sup -1} of CDF Run II data. Using a sample of 504 opposite sign e{tau} events with a total expected background of 190 events, we obtain {sigma}(p{bar p} {yields} Z) {center_dot} {Beta}(Z {yields} {tau}{tau}) = 263 {+-} 23(stat) {+-} 14(syst) {+-} 15(lumi) pb, in agreement with the next-to-next-to-leading order QCD prediction. This is the first CDF cross section measurement using hadronically-decaying taus in Run II.
Date: February 1, 2007
Creator: Abulencia, A.
Object Type: Article
System: The UNT Digital Library
Search for new physics in lepton + photon + X events with 929 pb**(-1) of p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Search for new physics in lepton + photon + X events with 929 pb**(-1) of p anti-p collisions at s**(1/2) = 1.96-TeV

The authors present results of a search at CDF in 929 {+-} 56 pb{sup -1} of p{bar p} collisions at 1.96 TeV for the anomalous production of events containing a high-transverse momentum charged lepton ({ell}, either e or {mu}) and photon ({gamma}), accompanied by missing transverse energy (E{sub T}), and/or additional leptons and photons, and jets (X). They use the same selection criteria as in a previous CDF Run I search, but with an order-magnitude larger data set, a higher p{bar p} collisions energy, and the CDF II detector. They find 163 {ell}{gamma}E{sub T} + X events, compared to an expectation of 150.6 {+-} 13.0 events. They observe 74 {ell}{ell}{gamma} + X events, compared to an expectation of 65.1 {+-} 7.7 events. They find no events similar to the Run II ee{gamma}{gamma}E{sub T} event.
Date: February 1, 2007
Creator: Abulencia, A.; /Illinois U., Urbana; Adelman, J.; U., /Chicago; Affolder, T.; /UC, Santa Barbara et al.
Object Type: Article
System: The UNT Digital Library
Observation of B0(s) ---> psi(2S)phi and measurement of ratio of branching fractions B(B0(s) ---> psi(2S)phi) / B(B0(s) ---> J/psi phi) (open access)

Observation of B0(s) ---> psi(2S)phi and measurement of ratio of branching fractions B(B0(s) ---> psi(2S)phi) / B(B0(s) ---> J/psi phi)

The authors report the first observation of B{sub s}{sup 0} {yields} {psi}(2S){phi} decay in p{bar p} collisions {radical}s = 1.96 TeV using 360 pb{sup -1} of data collected by the CDF II detector at the Fermilab Tevatron. They observe 20.2 {+-} 5.0 and 12.3 {+-} 4.1 B{sub s}{sup 0} {yields} {psi}(2S){phi} candidates, in {psi}(2S) {yields} {mu}{sup +}{mu}{sup -} and {psi}(2S) {yields} J/{psi}{pi}{sup +}{pi}{sup -} decay modes, respectively. They present a measurement of the relative branching fraction {Beta}(B{sub s}{sup 0} {yields} {psi}(2S){phi})/{Beta}(B{sub s}{sup 0} {yields} J/{psi}{phi}) = 0.52 {+-} 0.13(stat.) {+-} 0.04(syst.) {+-} 0.06(BR) using the {psi}(2S) {yields} {mu}{sup +}{mu}{sup -} decay mode.
Date: February 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, Anthony A.; Akimoto, T.; Albrow, M.G. et al.
Object Type: Article
System: The UNT Digital Library
Search for Z' ---> e+ e- using dielectron mass and angular distribution (open access)

Search for Z' ---> e+ e- using dielectron mass and angular distribution

The authors search Z{prime} bosons in dielectron events produced in p{bar p} collisions at {radical}s = 1.96 TeV, using a 0.45 fb{sup -1} dataset accumulated with the CDF II detector at the Fermilab Tevatron. To identify the Z{prime} {yields} e{sup +}e{sup -} signal, both the dielectron invariant mass distribution and the angular distribution of the electron pair are used. No evidence of a signal is found, and 95% confidence level lower limits are set on the Z{prime} mass for several models. Limits are also placed on the mass and gauge coupling of a generic Z{prime}, as well as on the contact interaction mass scales for different helicity structure scenarios.
Date: February 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, Anthony A.; Akimoto, T.; Albrow, M.G. et al.
Object Type: Article
System: The UNT Digital Library
Measurement of the top quark mass using template methods on dilepton events in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Measurement of the top quark mass using template methods on dilepton events in p anti-p collisions at s**(1/2) = 1.96-TeV

The authors describe a measurement of the top quark mass from events produced in p{bar p} collisions at a center-of-mass energy of 1.96 TeV, using the Collider Detector at Fermilab. They identify t{bar t} candidates where both W bosons from the top quarks decay into leptons (e{nu}, {mu}{nu}, or {tau}{nu}) from a data sample of 360 pb{sup -1}. The top quark mass is reconstructed in each event separately by three different methods, which draw upon simulated distributions of the neutrino pseudorapidity, t{bar t} longitudinal momentum, or neutrino azimuthal angle in order to extract probability distributions for the top quark mass. For each method, representative mass distributions, or templates, are constructed from simulated samples of signal and background events, and parameterized to form continuous probability density functions. A likelihood fit incorporating these parameterized templates is then performed on the data sample masses in order to derive a final top quark mass. Combining the three template methods, taking into account correlations in their statistical and systematic uncertainties, results in a top quark mass measurement of 170.1 {+-} 6.0(stat.) {+-} 4.1(syst.) GeV/c{sup 2}.
Date: February 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Object Type: Article
System: The UNT Digital Library
First Measurement of the Ratio of Central-Electron to Forward-Electron W Partial Cross Sections in p anti-p Collisions at s**(1/2) = 1.96 TeV (open access)

First Measurement of the Ratio of Central-Electron to Forward-Electron W Partial Cross Sections in p anti-p Collisions at s**(1/2) = 1.96 TeV

We present a measurement of {sigma}(p{bar p} {yields} W) x {Beta}(W {yields} e{nu}) at {radical}s = 1.96 TeV, using electrons identified in the forward region (1.2 < |{eta}| < 2.8) of the CDF II detector. The data correspond to an integrated luminosity of 223 pb{sup -1}. We measure {sigma} x {Beta} = 2796 {+-} 13(stat){sub -90}{sup +95}(syst){+-}162 (lum) pb. Combining this result with a previous CDF measurement obtained using electrons in the central region (|{eta}| {approx}< 1), we present the first measurement of the ratio of central-electron to forward-electron W partial cross sections R{sub exp} = 0.925 {+-} 0.006(stat){+-}0.032(syst), consistent with theoretical predictions using CTEQ and MRST parton distribution functions.
Date: February 1, 2007
Creator: Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Object Type: Article
System: The UNT Digital Library
ADVANCED COMPOSITE WIND TURBINE BLADE DESIGN BASED ON DURABILITY AND DAMAGE TOLERANCE (open access)

ADVANCED COMPOSITE WIND TURBINE BLADE DESIGN BASED ON DURABILITY AND DAMAGE TOLERANCE

The objective of the program was to demonstrate and verify Certification-by-Analysis (CBA) capability for wind turbine blades made from advanced lightweight composite materials. The approach integrated durability and damage tolerance analysis with robust design and virtual testing capabilities to deliver superior, durable, low weight, low cost, long life, and reliable wind blade design. The GENOA durability and life prediction software suite was be used as the primary simulation tool. First, a micromechanics-based computational approach was used to assess the durability of composite laminates with ply drop features commonly used in wind turbine applications. Ply drops occur in composite joints and closures of wind turbine blades to reduce skin thicknesses along the blade span. They increase localized stress concentration, which may cause premature delamination failure in composite and reduced fatigue service life. Durability and damage tolerance (D&DT) were evaluated utilizing a multi-scale micro-macro progressive failure analysis (PFA) technique. PFA is finite element based and is capable of detecting all stages of material damage including initiation and propagation of delamination. It assesses multiple failure criteria and includes the effects of manufacturing anomalies (i.e., void, fiber waviness). Two different approaches have been used within PFA. The first approach is Virtual Crack Closure Technique …
Date: February 16, 2012
Creator: Abumeri, Galib & Abdi, Frank
Object Type: Report
System: The UNT Digital Library
Instabilities of higher dimensional compactifications (open access)

Instabilities of higher dimensional compactifications

Various schemes for cosmological compactification of higher dimensional theories are considered. Possible instabilities which drive the ground state with static internal space to de Sitter-like expansion of all dimensions are discussed. These instabilities are due to semiclassical barrier penetration and classical thermal fluctuations. For the case of the ten dimensional Chapline-Manton action, it is possible to avoid such difficulties by balancing one-loop Casimir corrections against monopole contributions from the field strength H/sub MNP/ and fermionic condensates. 10 refs.
Date: February 1, 1987
Creator: Accetta, F.S.
Object Type: Article
System: The UNT Digital Library
A Comprehensive Study of Surface Chemistry for Application to Engine NOx Aftertreatment (open access)

A Comprehensive Study of Surface Chemistry for Application to Engine NOx Aftertreatment

This work focuses on developing a scientific understanding of the processes associated with NO{sub x} trap operation. NO{sub x} traps are the most advanced technology for achieving future emissions standards with diesel engines. Successful development of NO{sub x} traps will allow widespread use of diesel engines in light-duty vehicles, reducing oil imports by as much as 60%. Diesel engines have a high efficiency and low maintenance that makes them the ideal choice for transportation applications. Use of diesel engines in all light-duty vehicles would reduce oil consumption in the USA by 30% and oil imports by 60%, considerably improving our energy security. For heavy trucks, there is no viable alternative to diesel engines. Only diesel engines can provide the necessary high efficiency and long life. These benefits are offset by high emission of pollutants. Diesel engines have high emissions of NO{sub x} and particulate matter. Over the last 20 years, EPA has been reducing allowable emissions from diesel engines, and NO{sub x} emissions are scheduled to be cut by a factor of 10 over the next 7 years. The target NO{sub x} emissions for year 2010 is 0.20 g/hp-hr. This value is well below 1 g/hp-hr, which has been identified …
Date: February 19, 2004
Creator: Aceves, S M; Piggot, T; Pitz, W; Mundy, C; Kuo, W & Havstad, M
Object Type: Report
System: The UNT Digital Library
Spatial Analysis of Emissions Sources for HCCI Combustion at Low Loads Using a Multi-Zone Model (open access)

Spatial Analysis of Emissions Sources for HCCI Combustion at Low Loads Using a Multi-Zone Model

We have conducted a detailed numerical analysis of HCCI engine operation at low loads to investigate the sources of HC and CO emissions and the associated combustion inefficiencies. Engine performance and emissions are evaluated as fueling is reduced from typical HCCI conditions, with an equivalence ratio f = 0.26 to very low loads (f = 0.04). Calculations are conducted using a segregated multi-zone methodology and a detailed chemical kinetic mechanism for iso-octane with 859 chemical species. The computational results agree very well with recent experimental results. Pressure traces, heat release rates, burn duration, combustion efficiency and emissions of hydrocarbon, oxygenated hydrocarbon, and carbon monoxide are generally well predicted for the whole range of equivalence ratios. The computational model also shows where the pollutants originate within the combustion chamber, thereby explaining the changes in the HC and CO emissions as a function of equivalence ratio. The results of this paper contribute to the understanding of the high emission behavior of HCCI engines at low equivalence ratios and are important for characterizing this previously little explored, yet important range of operation.
Date: February 20, 2004
Creator: Aceves, S. M.; Flowers, D. L.; Espinosa-Loza, F.; Martinez-Frias, J.; Dec, J. E.; Sjoberg, M. et al.
Object Type: Article
System: The UNT Digital Library
Fuel and Additive Characterization for HCCI Combustion (open access)

Fuel and Additive Characterization for HCCI Combustion

This paper shows a numerical evaluation of fuels and additives for HCCl combustion. First, a long list of candidate HCCl fuels is selected. For all the fuels in the list, operating conditions (compression ratio, equivalence ratio and intake temperature) are determined that result in optimum performance under typical operation for a heavy-duty engine. Fuels are also characterized by presenting Log(p)-Log(T) maps for multiple fuels under HCCl conditions. Log(p)-Log(T) maps illustrate important processes during HCCl engine operation, including compression, low temperature heat release and ignition. Log(p)-Log(T) diagrams can be used for visualizing these processes and can be used as a tool for detailed analysis of HCCl combustion. The paper also includes a ranking of many potential additives. Experiments and analyses have indicated that small amounts (a few parts per million) of secondary fuels (additives) may considerably affect HCCl combustion and may play a significant role in controlling HCCl combustion. Additives are ranked according to their capability to advance HCCl ignition. The best additives are listed and an explanation of their effect on HCCl combustion is included.
Date: February 12, 2003
Creator: Aceves, S. M.; Flowers, D.; Martinez-Frias, J.; Espinosa-Loza, F.; Pitz, W. J. & Dibble, R.
Object Type: Article
System: The UNT Digital Library
Thin-film characterization and flaw detection. Final report, February 1, 1993--November 31, 1997 (open access)

Thin-film characterization and flaw detection. Final report, February 1, 1993--November 31, 1997

The objectives were to determine the elastic constants of thin films deposited on substrates, to measure residual stress and to detect and characterize defects in thin film substrate configurations. There are many present and potential applications of configurations consisting of a thin film deposited on a substrate. Thin films that are deposited to improve the hardness and/or the thermal properties of surfaces were of principal interest in this work. Thin film technology does, however, also include high {Tc} superconductor films, films for magnetic recording, superlattices and films for band-gap engineering and quantum devices. The studies that were carried out on this project also have relevance to these applications. Both the film and the substrate are generally anisotropic. A line-focus acoustic microscope has been used to measure the speed of surface acoustic waves (SAW) in the thin film/substrate system. This microscope has unique advantages for measurements in anisotropic media. Analytical and numerical techniques have been employed to extract the desired information on the thin film from the measured SAW data. Results include: (1) analytical and numerical techniques for the direct problem and for inverse methods; (2) measurements of homogeneous and superlattice film constants; (3) investigation of the effect of surface roughness …
Date: February 25, 1998
Creator: Achenbach, J. D.
Object Type: Report
System: The UNT Digital Library
Hot dry rock reservoir characterization and modeling. Progress report, October 1, 1978-September 30, 1979. Final report (open access)

Hot dry rock reservoir characterization and modeling. Progress report, October 1, 1978-September 30, 1979. Final report

Resuls of analytical and experimental studies on hydraulic fracturing and on the characterization and modeling of hot dry rock geothermal energy reservoirs are presented. The first four Chapters are concerned with problems of thermal cracking and heat transfer, with fluid flow through large cracks, and with the stable and unstable growth of water-filled cracks under internal pressure and thermal loading. Experiments are reported, which present visually observable hydraulic fractures in transparent materials to demonstrate the interaction between hydraulic fractures and the development of thermal cracks. Seismic detection of hydraulic fractures is discussed, and a method to invert crack-scattering data is presented. Separate abstracts were prepared for each of the six chapters.
Date: February 1, 1980
Creator: Achenbach, J. D.; Bazant, Z. P.; Dundurs, J.; Keer, L.M.; Nemat-Nasser, S.; Mura, T. et al.
Object Type: Report
System: The UNT Digital Library
Transmission System Performance Analysis for High-Penetration Photovoltaics (open access)

Transmission System Performance Analysis for High-Penetration Photovoltaics

This study is an assessment of the potential impact of high levels of penetration of photovoltaic (PV) generation on transmission systems. The effort used stability simulations of a transmission system with different levels of PV generation and load.
Date: February 1, 2008
Creator: Achilles, S.; Schramm, S. & Bebic, J.
Object Type: Report
System: The UNT Digital Library
Recent regulatory experience of low-Btu coal gasification. Volume III. Supporting case studies (open access)

Recent regulatory experience of low-Btu coal gasification. Volume III. Supporting case studies

The MITRE Corporation conducted a five-month study for the Office of Resource Applications in the Department of Energy on the regulatory requirements of low-Btu coal gasification. During this study, MITRE interviewed representatives of five current low-Btu coal gasification projects and regulatory agencies in five states. From these interviews, MITRE has sought the experience of current low-Btu coal gasification users in order to recommend actions to improve the regulatory process. This report is the third of three volumes. It contains the results of interviews conducted for each of the case studies. Volume 1 of the report contains the analysis of the case studies and recommendations to potential industrial users of low-Btu coal gasification. Volume 2 contains recommendations to regulatory agencies.
Date: February 1, 1980
Creator: Ackerman, E.; Hart, D.; Lethi, M.; Park, W. & Rifkin, S.
Object Type: Report
System: The UNT Digital Library
Interactions of CO{sub 2} With Temperature and Other Climate Variables: Response of Vegetation. Final Report, September 1, 1988--August 31, 1993 (open access)

Interactions of CO{sub 2} With Temperature and Other Climate Variables: Response of Vegetation. Final Report, September 1, 1988--August 31, 1993

The current project was initiated in 1991, and full details of the scope of the project are contained in the original proposal. that original proposal was reviewed and approved for three years funding. Progress made in 1991-92 and 1992-93 was described in annual Progress Reports and Statements of Work. This document summarizes progress made over the duration of the project, but with an emphasis on the final year`s (1993-94) results. Several of the important experiments are ongoing, to the extent that alternative funding could be arranged, and analyses of data from several of the earlier completed experiments is continuing. Therefore, this Final Report is also intermediary in nature, and additional results from this project will be reported in the open literature in the future. The overall objectives of the project were: (1) to examine experimentally, for major crop species, the interacting effects of CO{sub 2} concentration, temperature, and water availability on plant growth and development, (2) to model these interactions, and (3) to continue developing physiologically-based mechanistic models for predicting crop response to increased CO{sub 2} concentration and future global climate change.
Date: February 1, 1995
Creator: Acock, B. & Kimball, B. A.
Object Type: Report
System: The UNT Digital Library