Serial/Series Title
Winter Fuels Report
4
Petroleum Marketing Monthly
3
ARM Facilities Newsletter
2
Fiscal Year 2007
2
Hindered Diffusion of Asphaltenes at Elevated Temperature and Pressure Progress Report
2
Lignite Fuel Enhancement Progress Report
2
Development of Continuous Solvent Extraction Processes for Coal Derived Carbon Products Quarterly Report
1
Enhancement of Equilibrium Shift in Dehydrogenation Reactions Using a Novel Membrane Reactor Semi-Annual Report
1
Fiscal Year 1999
1
Fiscal Year 2000
1
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A three-dimensional validation of crack curvature in muscovite mica
Experimental and computational efforts focused on characterizing crack tip curvature in muscovite mica. Wedge-driven cracks were propagated under monochromatic light. Micrographs verified the subtle curvature of the crack front near the free surface. A cohesive approach was employed to model mixed-mode fracture in a three-dimensional framework. Finite element calculations captured the crack curvature observed in experiment.
Date:
January 7, 2001
Creator:
Hill, J. C.; Foulk, J. W., III; Klein, P. A. & Chen, E. P.
Object Type:
Article
System:
The UNT Digital Library
Rapid Column Extraction method for SoilRapid Column Extraction method for Soil
The analysis of actinides in environmental soil and sediment samples is very important for environmental monitoring as well as for emergency preparedness. A new, rapid actinide separation method has been developed and implemented that provides total dissolution of large soil samples, high chemical recoveries and effective removal of matrix interferences. This method uses stacked TEVA Resin{reg_sign}, TRU Resin{reg_sign} and DGA-Resin{reg_sign} cartridges from Eichrom Technologies (Darien, IL, USA) that allows the rapid separation of plutonium (Pu) neptunium (Np), uranium (U), americium (Am), and curium (Cm) using a single multi-stage column combined with alpha spectrometry. The method combines a rapid fusion step for total dissolution to dissolve refractory analytes and matrix removal using cerium fluoride precipitation to remove the difficult soil matrix. By using vacuum box cartridge technology with rapid flow rates, sample preparation time is minimized.
Date:
November 7, 2005
Creator:
Maxwell, Sherrod, L., III & Culligan, Brian K.
Object Type:
Article
System:
The UNT Digital Library
Hydragard Sampling of Melter Feed Slurry Containing CST: A Nonproprietary Summary
This report is a modified version of WSRC-TR-2000-00378, Revision 0. All proprietary data related to Crystalline Silicotitanate have been removed for this version.
Date:
June 7, 2001
Creator:
Edwards, T. B.; Qureshi, Z. H.; Harbour, J. R. & Smith, F. G., III
Object Type:
Report
System:
The UNT Digital Library
Urban Wood/Coal Co-Firing in the Bellefield Boilerplant
During the second quarter, important preparatory work was continued so that the experimental activities can begin toward the end of the third quarter or early in the fourth quarter. The Environmental Questionnaire was submitted to the U.S. DOE National Energy Technology Laboratory (NETL), after thorough review by the Bellefield Boiler Plant (BBP). Letters were submitted to the Allegheny County Health Department (ACHD) and the Pennsylvania Department of Environmental Protection (PADEP) to seek R and D variances for permits at the BBP, the J. A. Rutter Company (JARC), and Emery Tree Service (ETS) for their portion of the project. Memoranda of understanding were executed by the University of Pittsburgh (University) with the BBP, JARC and ETS. Construction wood was collected from Thompson Properties. Discussions were held with the BBP and Energy Systems Associates (ESA), the BBP's engineering consultant. Presentations describing the University of Pittsburgh Wood/Coal Co-Firing Program were provided to the American Chemical Society (ACS), the Federal Energy Management Program (FEMP), the Upgraded Coal Interest Group (UCIG) of the Electric Power Research Institute (EPRI), the Engineering Center for Environment and Energy (ECEE) of the University of Pittsburgh, the Pittsburgh Coal Conference (PCC), the Pennsylvania Ethanol Workshop, BioEnergy 2000 and the Kick-Off …
Date:
March 7, 2001
Creator:
Cobb, James T., Jr.; Geiger, Gene E. & III, William W. Elder
Object Type:
Report
System:
The UNT Digital Library
The Application of Global Kinetic Models to HMX Beta-Delta Transition and Cookoff Processes
The reduction of the number of reactions in kinetic models for both the HMX beta-delta phase transition and thermal cookoff provides an attractive alternative to traditional multi-stage kinetic models due to reduced calibration effort requirements. In this study, we use the LLNL code ALE3D to provide calibrated kinetic parameters for a two-reaction bidirectional beta-delta HMX phase transition model based on Sandia Instrumented Thermal Ignition (SITI) and Scaled Thermal Explosion (STEX) temperature history curves, and a Prout-Tompkins cookoff model based on One-Dimensional Time to Explosion (ODTX) data. Results show that the two-reaction bidirectional beta-delta transition model presented here agrees as well with STEX and SITI temperature history curves as a reversible four-reaction Arrhenius model, yet requires an order of magnitude less computational effort. In addition, a single-reaction Prout-Tompkins model calibrated to ODTX data provides better agreement with ODTX data than a traditional multi-step Arrhenius model, and can contain up to 90% less chemistry-limited time steps for low-temperature ODTX simulations. Manual calibration methods for the Prout-Tompkins kinetics provide much better agreement with ODTX experimental data than parameters derived from Differential Scanning Calorimetry (DSC) measurements at atmospheric pressure. The predicted surface temperature at explosion for STEX cookoff simulations is a weak function of …
Date:
December 7, 2006
Creator:
Wemhoff, A. P.; Burnham, A. K. & Nichols, A. L., III
Object Type:
Article
System:
The UNT Digital Library
Aging and Fracture of Human Cortical Bone and Tooth Dentin
Mineralized tissues, such as bone and tooth dentin, serve as structural materials in the human body and, as such, have evolved to resist fracture. In assessing their quantitative fracture resistance or toughness, it is important to distinguish between intrinsic toughening mechanisms which function ahead of the crack tip, such as plasticity in metals, and extrinsic mechanisms which function primarily behind the tip, such as crack bridging in ceramics. Bone and dentin derive their resistance to fracture principally from extrinsic toughening mechanisms which have their origins in the hierarchical microstructure of these mineralized tissues. Experimentally, quantification of these toughening mechanisms requires a crack-growth resistance approach, which can be achieved by measuring the crack-driving force, e.g., the stress intensity, as a function of crack extension ("R-curve approach"). Here this methodology is used to study of the effect of aging on the fracture properties of human cortical bone and human dentin in order to discern the microstructural origins of toughness in these materials.
Date:
May 7, 2008
Creator:
Ager, Joel; Koester, Kurt J.; Ager, Joel W., III & Ritchie, Robert O.
Object Type:
Article
System:
The UNT Digital Library
Direct Observation of Room-Temperature Polar Ordering in Colloidal GeTe Nanocrystals
Ferroelectrics and other materials that exhibit spontaneous polar ordering have demonstrated immense promise for applications ranging from non-volatile memories to microelectromechanical systems. However, experimental evidence of polar ordering and effective synthetic strategies for accessing these materials are lacking for low-dimensional nanomaterials. Here, we demonstrate the synthesis of size-controlled nanocrystals of the polar material germanium telluride (GeTe) using colloidal chemistry and provide the first direct evidence of room-temperature polar ordering in nanocrystals less than 5 nm in size using aberration-corrected transmission electron microscopy. Synchrotron x-ray diffraction and Raman studies demonstrate a sizeable polar distortion and a reversible size-dependent polar phase transition in these nanocrystals. The stability of polar ordering in solution-processible nanomaterials suggests an economical avenue to Tbit/in2-density non-volatile memory devices and other applications.
Date:
December 7, 2009
Creator:
Polking, Mark J.; Zheng, Haimei; Urban, Jeffrey J.; Milliron, Delia J.; Chan, Emory; Caldwell, Marissa A. et al.
Object Type:
Article
System:
The UNT Digital Library
Band anticrossing effects in Mg{sub y}Zn{sub 1-y}Te{sub 1-x}Se{sub x} alloys
None
Date:
August 7, 2001
Creator:
Wu, J.; Walukiewicz, W.; Yu, K. M.; Ager, J. W., III; Shan, W.; Haller, E. E. et al.
Object Type:
Article
System:
The UNT Digital Library
Nanocoatings for High-Efficiency Industrial Hydraulic and Tooling Systems
Industrial manufacturing in the U.S. accounts for roughly one third of the 98 quadrillion Btu total energy consumption. Motor system losses amount to 1.3 quadrillion Btu, which represents the largest proportional loss of any end-use category, while pumps alone represent over 574 trillion BTU (TBTU) of energy loss each year. The efficiency of machines with moving components is a function of the amount of energy lost to heat because of friction between contacting surfaces. The friction between these interfaces also contributes to downtime and the loss of productivity through component wear and subsequent repair. The production of new replacement parts requires additional energy. Among efforts to reduce energy losses, wear-resistant, low-friction coatings on rotating and sliding components offer a promising approach that is fully compatible with existing equipment and processes. In addition to lubrication, one of the most desirable solutions is to apply a protective coating or surface treatment to rotating or sliding components to reduce their friction coefficients, thereby leading to reduced wear. Historically, a number of materials such as diamond-like carbon (DLC), titanium nitride (TiN), titanium aluminum nitride (TiAlN), and tungsten carbide (WC) have been examined as tribological coatings. The primary objective of this project was the development …
Date:
January 7, 2011
Creator:
Higdon, Clifton B., III
Object Type:
Report
System:
The UNT Digital Library
ESF/Repository Interface Layout Coordinate Geometry Analysis
The purpose of this analysis is to produce coordinate geometry calculations sufficient to establish the position of the conceptual Geologic Repository Operations Area (GROA) as it relates to the position of the Exploratory Studies Facility (ESF) planned exploratory drifting and the physical site. The focus of this analysis is to show the mathematical validity of the arrangement. The documentation which supports the development of the configuration can be found in References 5.3 and 5.4. This analysis supports the production of the ESF/GROA Interface drawings which are used by the Project to demonstrate and control the physical interfaces between the ESF and Repository.
Date:
November 7, 1995
Creator:
McKenzie, D.G., III
Object Type:
Report
System:
The UNT Digital Library
Photon Enhanced Thermionic Emission for Solar Energy Harvesting Final Report to the Global Climate and Energy Project
None
Date:
May 7, 2013
Creator:
Melosh, Nicholas; Shen, Zhi-Xun; Schwede, Jared; Riley, Dan; Rosenthal, Samuel; Narasimhan, Vijay et al.
Object Type:
Article
System:
The UNT Digital Library
Fine-scale spatial response of CdZnTe radiation detectors
Several studies have suggested that the uniformity of Cadmium Zinc Telluride (CZT) detectors play an important role in their performance when operated as gamma-ray spectrometers. However the detailed gamma response of simple planar detectors as a function of position over the device area is largely unknown. To address this issue the authors have built a system capable of measuring the detector response with a resolution of {approximately}250 {micro}m. The system consists of a highly collimated ({approximately}200 {micro}m) photon source (<150 kev) scanned over the detector using a computer controlled two-axis translation stage. Fifteen samples configured as planar detectors were examined with the new apparatus. The material grade of the detectors examined varied from counter to select discriminator. Two classes of spatial response variation were observed and are presented here. Infrared (IR) transmission images were also acquired for each sample and correlation between features in the pulse height spectrum and crystalline defects were observed.
Date:
November 7, 1998
Creator:
Brunett, B. A.; van Scyoc, J. M.; Hilton, N. R.; Lund, J. C.; James, R. B. & Schlesinger, T. E.
Object Type:
Article
System:
The UNT Digital Library
Multi-parameter high-resolution spatial maps of a CdZnTe radiation detector array
Resistivity results from a 48x48 pixelated CdZnTe (CZT) radiation detector array are presented alongside X-ray topography and detector mapping with a collimated gamma-ray beam. By using a variety of measurements performed on the same sample and registering each data set relative to the others, the spatial dependence of relationships between them was examined. The local correlations between resistivity and one measure of detector performance were strongly influenced by the positions of grain boundaries and other gross crystal defects in the sample. These measurements highlight the need for material studies of spatially heterogeneous CZT to record position information along with the parameters under study.
Date:
November 7, 1998
Creator:
Hilton, N. R.; Barber, H. B.; Brunett, B. A.; Eskin, J. D.; Goorsky, M. S.; James, R. B. et al.
Object Type:
Article
System:
The UNT Digital Library
Simultaneous Microwave Imaging System for Density and Temperature Fluctuation Measurements on TEXTOR
Diagnostic systems for fluctuation measurements in plasmas have, of necessity, evolved from simple 1-D systems to multi-dimensional systems due to the complexity of the MHD and turbulence physics of plasmas illustrated by advanced numerical simulations. Using the recent significant advancements in millimeter wave imaging technology, Microwave Imaging Reflectometry (MIR) and Electron Cyclotron Emission Imaging (ECEI), simultaneously measuring density and temperature fluctuations, are developed for TEXTOR. The MIR system was installed on TEXTOR and the first experiment was performed in September, 2003. Subsequent MIR campaigns have yielded poloidally resolved spectra and assessments of poloidal velocity. The new 2-D ECE Imaging system (with a total of 128 channels), installed on TEXTOR in December, 2003, successfully captured a true 2-D images of Te fluctuations of m=1 oscillation (''sawteeth'') near the q {approx} 1 surface for the first time.
Date:
May 7, 2004
Creator:
Park, H.; Mazzucato, E.; Munsat, T.; Domier, C. W.; Johnson, M.; N. C. Luhmann, Jr. et al.
Object Type:
Report
System:
The UNT Digital Library
Behavior of carbon-14 in waste packages for spent fuel in a repository in tuff. Revision 1
Analysis of gas from a heated air-filled canister containing a spent fuel assembly before and after rupture of a fuel rod shows that about 1.5 mCi of {sup 14}C from the external surface of the assembly was rapidly oxidized and released as {sup 14}CO{sub 2} in excess oxygen at 275{sup 0}C and 10{sup 4}/sup rad/h. After rupture, an additional 0.3 mCi was released, probably also from the external surface. The total {sup 14}C inventory in the entire 15 x 15 rod assembly including structural hardware is estimated to be 690 mCi. These measurements indicate that account will have to be taken of the time distribution of lifetimes of the canisters, and a broad definition of the "engineered system" may be necessary, in order to meet 10CFR60 requirements with spent fuel in a repository in tuff. 22 refs., 1 tab.
Date:
November 7, 1984
Creator:
Van Konynenburg, R. A.; Smith, C. F.; Culham, H. W. & Otto, C. H., Jr.
Object Type:
Article
System:
The UNT Digital Library
Geothermal materials survey: Baca Geothermal Demonstration Power Plant, Baca, New Mexico
The results of a materials survey for the Baca 50 MW(e) single flash geothermal plant in the Valles Caldera of New Mexico are presented. From the design documents provided, materials proposed for use in contact with the plant atmosphere, the two-phase geofluid, the separated steam, and the recirculating condensate cooling water were assessed for suitability. Special emphasis was given to records of performance of the materials in other geothermal plants. Based upon these considerations of chemical reactivity and plant operating experience, a number of recommendations were made.
Date:
October 7, 1980
Creator:
Ellis, P. F., II
Object Type:
Report
System:
The UNT Digital Library
Using Chemicals to Optimize Conformance Control in Fractured Reservoirs
The objectives of this project are: (1) to develop a capability to predict and optimize the ability of gels to reduce permeability to water more than that to oil or gas, (2) to develop procedures for optimizing blocking agent placement in wells where hydraulic fractures cause channeling problems, and (3) to develop procedures to optimize blocking agent placement in naturally fractured reservoirs. Work was directed at both injection wells and production wells and at vertical, horizontal, and highly deviated wells.
Date:
September 7, 2001
Creator:
Seright, Randall; Liang, Jenn-Tai; Schrader, Richard; Hagstrom, John, II; Wang, Ying; Kumar, Anand et al.
Object Type:
Report
System:
The UNT Digital Library
Advances in X-Ray Computed Microtomography at the NSLS
The X-Ray Computed Microtomography workstation at beamline X27A at the NSLS has been utilized by scientists from a broad range of disciplines from industrial materials processing to environmental science. The most recent applications are presented here as well as a description of the facility that has evolved to accommodate a wide variety of materials and sample sizes. One of the most exciting new developments reported here resulted from a pursuit of faster reconstruction techniques. A Fast Filtered Back Transform (FFBT) reconstruction program has been developed and implemented, that is based on a refinement of the ''gridding'' algorithm first developed for use with radio astronomical data. This program has reduced the reconstruction time to 8.5 sec for a 929 x 929 pixel{sup 2} slice on an R10,000 CPU, more than 8x reduction compared with the Filtered Back-Projection method.
Date:
August 7, 1998
Creator:
Dowd, B. A.
Object Type:
Article
System:
The UNT Digital Library