Partner
UNT Libraries Government Documents Department
2,571
UNT Libraries Special Collections
282
Oklahoma Historical Society
245
UNT Libraries
101
Sterling Municipal Library
26
Alvin Community College
12
Keystone Crossroads Historical Society
12
Rice University Woodson Research Center
10
San Antonio Public Library
10
Bastrop Public Library
9
75 More
Collection
Office of Scientific & Technical Information Technical Reports
2,506
Texas Digital Newspaper Program
276
KXAS-NBC 5 News Collection
178
Oklahoma Digital Newspaper Program
161
Tocker Foundation Grant
148
UNT Theses and Dissertations
82
Oklahoma Publishing Company Photography Collection
78
The Black Academy of Arts and Letters Records
55
Chickasha Newspaper Collection
42
The Baytown Sun
26
125 More
Degree Department
Department of Psychology
12
Department of Counseling, Development and Higher Education
8
College of Music
5
Department of History
5
Department of Radio, Television and Film
5
Department of Biological Sciences
4
Department of Political Science
4
Department of Sociology
4
Graduate Studies in English
4
Department of Teacher Education and Administration
3
25 More
Degree Discipline
Degree Level
Country
States
Year
Month
Language
Results:
1 - 24 of
3,534
next
Sulfur removal in advanced two stage pressurized fluidized bed combustion. Technical report, March 1--May 31, 1995
The objective of this study is to obtain data on the rates and the extent of sulfation reactions involving partially sulfided calcium-based sorbents, and oxygen as well as sulfur dioxide, at operating conditions closely simulating those prevailing in the second stage (combustor) of Advanced Two-Stage Pressurized Fluidized-Bed Combustors. In these systems the CO{sub 2} partial pressure generally exceeds the equilibrium value for calcium carbonate decomposition. Therefore, calcium sulfate is produced through the reactions between SO{sub 2} and calcium carbonate as well as the reaction between calcium sulfide and oxygen. To achieve this objective, the rates of reaction involving SO{sub 2} and oxygen, calcium sulfide and calcium carbonate will be determined by conducting tests in a pressurized thermogravimetric analyzer unit. The sulfate tests conducted during this quarter, focused on the determination of the rate of sulfation reaction involving partially sulfided half-calcined dolomite and oxygen. The test parameters included CO{sub 2} and O{sub 2} concentrations, reaction temperature and pressure, as well as the sorbent particle size. The results obtained during this quarter suggest that the rate of sulfation reaction involving partially sulfided half-calcined dolomite and oxygen is very fast at temperatures above 850 C which rapidly increases with increasing temperature, achieving more …
Date:
December 31, 1995
Creator:
Abbasian, J.
Object Type:
Report
System:
The UNT Digital Library
Development of regenerable copper-based sorbents for hot gas cleanup. Technical report, September 1, 1995--November 30, 1995
The overall objective of this study is to determine the effectiveness of the copper-chromite sorbent (developed in previous ICCI-funded projects) for longer duration application under optimum conditions in the temperature range of 550{degrees}-650{degrees}C to minimize sorbent reduction and degradation during the cyclic process. To achieve this objective, several formulations of copper chromite sorbents are prepared. These sorbent formulations are screened for their desulfurization and regeneration capability at predetermined temperatures and gas residence times. The durability of the best sorbent formulation identified in the screening tests is evaluated in ``long-term`` durability tests conducted at the optimum operating conditions. This includes testing the sorbent in pellet and granular forms in packed- and fluidized-bed reactors. During this quarter, twenty one copper chromite-based sorbent formulations were prepared. Two sorbent formulations that have acceptable crush strength, designated as CuCr-10 and CuCr-21, were tested over 5 and 6 cycles respectively. The results indicate that both sorbents are reactive toward H{sub 2}S at 650{degrees}C and that the reactivity of the sorbents are relatively constant over the first 5 to 6 cycles. The H{sub 2}S prebreakthrough concentrations were generally about 20 to 30 ppm, making them suitable for IGCC application.
Date:
December 31, 1995
Creator:
Abbasian, J.; Slimane, R.B. & Hill, A.H.
Object Type:
Report
System:
The UNT Digital Library
Stabilization of spent sorbents from coal-based power generation processes. Technical report, September 1, 1995--November 30,1995
The overall objective of this study is to determine the effect of implementation of the new and more stringent EPA Protocol Test Method involving sulfide containing waste, on the suitability of the oxidized spent sorbents from gasification of of high sulfur coals for disposal in landfills, and to determine the optimum operating conditions in a ``final`` hydrolysis stage for conversion of the residual calcium sulfide in these wastes to materials that are suitable for disposal in landfills. An additional objective is to study the effect of ash on the regeneration and ash-sorbent separation steps in the Spent Sorbent Regeneration Process (SSRP). To achieve these objectives, a large set of oxidized samples of sulfided calcium-based sorbents (produced in earlier ICCI-funded programs) as well as oxidized samples of gasifier discharge (containing ash and spent sorbent) are tested according to the new EPA test protocol. Samples of the oxidized spent sorbents that do not pass the EPA procedure are reacted with water and carbon dioxide to convert the residual calcium sulfide to calcium carbonate. During this quarter, samples of oxidized sulfided calcium-based sorbents, including untreated calcium sulfide-containing feed materials, were analyzed using both weak acid and more stringent strong acid tests. Preliminary analysis …
Date:
December 31, 1995
Creator:
Abbassian, J. & Hill, A.H.
Object Type:
Report
System:
The UNT Digital Library
[Letter from Julie Abel to Robert Simerly, December 20, 1995]
Photocopy of a letter from Julie Abel, Program Associate, Getty Center for Education in the Arts, to Robert Simerly, Dean of University Outreach, Florida State University. The letter is in regards to their prior correspondence about the possibility of offering FSU graduate credits to participants at the Center's national profession development program in the upcoming summer.
Date:
December 20, 1995
Creator:
Abel, Julie
Object Type:
Letter
System:
The UNT Digital Library
[RE: Goals 2000 Grants]
Photocopy of a memo from Julie Abel, program assocation for the Getty Center for Education in the Arts, to the Regional Institute Directors. The memo is in regards to the directors getting in contact with their Goals 2000 Arts Education Leadership Fund project director to ensure that the programs and DBAE are part of their states reform plans. Enclosed with Abel's memo is a memo from Vicki Rosenberg regarding the important of participating in the states planning process.
Date:
December 19, 1995
Creator:
Abel, Julie
Object Type:
Letter
System:
The UNT Digital Library
[RE: Graduate Credit for Professional Development Programs]
Photocopy of a letter from Julie Abel, Program Associate, Getty Center for Education in the Arts, to Nancy Berry, Mickey Day, Nancy MacGregor, Jeff Patchen, Marilyn Stewart, Sheila Brown, Rick Lasher, Michael Parson and Marilyn Schnake. The letter is in regards to prior discussion of possibly offering graduate credits to participants at the Center's national professional development program in the upcoming summer. cc'd on the letter, Jack Davis, Val Marmillion, David Pankratz, Kathy Talley-Jones, Cristin Leonard-Wills, Bill McCarter and Vicki Rosenberg.
Date:
December 20, 1995
Creator:
Abel, Julie
Object Type:
Letter
System:
The UNT Digital Library
[RE: Graduate Credit for Professional Development Programs, December 20, 1995]
Photocopy of a letter from Julie Abel, the Getty Center, to the professional development program participants, Nancy Berry, Mickey Day, Nancy MacGregor, Jeff Patchen, Marilyn Stewart, Sheila Brown, Rick Lasher, Michael Parson and Marilyn Schnake. Copied on the letter are, Jack Davis, Val Marmillion, David Pankratz, Kathy Tally-Jones, Cristin Leonard-Wills, Bill McCarter (crossed out) and Vicki Rosenberg. The note is in regards to the Center's participation being able to receive graduate credits from the professional development programs in the summer and has attached a memo to Bob Simerly to discuss their efforts.
Date:
December 20, 1995
Creator:
Abel, Julie
Object Type:
Letter
System:
The UNT Digital Library
[RE: RIG Faculty Members]
Photocopy of a letter from Julie Able, Program Associate, Getty Center for Education in the Arts, to RIG directors. The letter is in regards to a request from the Center staff a list of RIG faculty members to use as resources as the Center regularly uses RIG people as program consultants. The faculty list must be received by January 11, 1996. cc'd on the letter is Vicki Rosenberg.
Date:
December 20, 1995
Creator:
Abel, Julie
Object Type:
Letter
System:
The UNT Digital Library
Role of C, O and H in III-V nitrides
The light ion impurities C, 0 and H have been implanted or diffused into GaN and related compounds and their effect on the electrical properties of these materials measured by Hall, C-V and SIMS as a function of annealing temperatures from 300--11OO{degree}C. While C in as-grown GaN appears to create an acceptor under MOMBE conditions, implanted C shows no measurable activity. Similarly, implanted 0 does not show any shallow donor activity after annealing at {le}700{degree}C, but can create high resistivity regions (10{sup 6} {Omega}/{open_square}) in GaN, AlInN and InGaN for device isolation when annealed at 500--70O{degree}C. Finally, hydrogen is found to passivate shallow donor and acceptor states in GaN, InN. InAlN and InGaN, with dissociation of the neutral complexes at >450{degree}C. The liberated hydrogen does not leave the nitride films until much higher annealing temperatures (>800{degree}C). Typical reactivation energies are {approximately}2.0 eV for impurity-hydrogen complexes.
Date:
December 1, 1995
Creator:
Abernathy, C. R.; Pearton, S. J.; MacKenzie, J. D.; Lee, J. W.; Vartuli, C. B.; Wilson, R. G. et al.
Object Type:
Article
System:
The UNT Digital Library
Abilene Philharmonic Playbill: December 16, 1995
Program for an Abilene Philharmonic concert that ran on December 16th during the 46th season. It includes information about the pieces performed, artists and musicians, and advertising from local companies.
Date:
December 1995
Creator:
Abilene Philharmonic
Object Type:
Pamphlet
System:
The Portal to Texas History
Development, Demonstration, Testing, and Evaluation Efforts Associated with the Oak Ridge Reservation`s Land Disposal Restrictions Federal Facility Compliance Agreement
On June 12, 1992, the U. S. Department of Energy Oak Ridge Operations Office and the U. S. Environmental Protection Agency (EPA) Region IV signed a Federal Facility Compliance Agreement (FFCA) to regulate the treatment of wastes governed by the Land Disposal Restrictions (LDR) of the Resource Conservation and Recovery Act (RCRA). Compliance Requirement 5 of the agreement states that `. . . DOE shall submit to EPA for review and approval a plan for the treatment of the LDR prohibited wastes identified in Appendices 1B, 2B, and 3B. This plan must identify the treatment strategy for such wastes to meet LDR treatment standards and must include a schedule, not to exceed two (2) years after the submittal of this plan (i.e., March 1995), for the evaluation and prioritization of treatment method options, treatability studies, if required, and technology development. The FFCA divided the mixed wastes currently stored on the Oak Ridge Reservation (ORR) into two categories. Appendix A listed those wastes for which existing treatment methods and facilities exist. Appendix B listed wastes for which no identified treatment methods or facilities exist on the ORR.
Date:
December 1995
Creator:
Abraham, T. J. & Conley, T. B.
Object Type:
Article
System:
The UNT Digital Library
Preconditioned gradient methods for sparse linear systems for very `large structural` problems
This paper deals with background and practical experience with preconditioned gradient methods for sparse linear systems for `very large` structural problems. The conjugate gradient method with diagonal preconditioning (CG/D) is demonstrated to substantially increase the size of structural problems that can be analyzed, significantly reduce computer storage requirements, and cut computing cost; thus allowing for much more detailed modeling and increased engineering efficiency. For one case for a structural system with 396,087 unknowns, the conjugate gradient method with diagonal preconditioning is demonstrated to be a factor of sixty faster than the direct method. For certain problems, however, the number of iterations required by the CG/D method is excessive and improved methods are needed. A stand-alone iterative solver research computer program was developed to evaluate the merits of various matrix preconditioners. A matrix preconditoner based on a shifted incomplete Cholesky factorization algorithm was demonstrated to be superior to other choices. The stand-alone program incorporates an effective data management strategy which utilizes disk and solid state auxiliary computer storage devices to make it possible to efficiently solve excessively large structural problems on state-of-the-art vector and parallel computers. The background of gradient methods, algorithms for their implementation, and practical experience in their applications …
Date:
December 1, 1995
Creator:
Abu-Shumays, I.K.; Hutula, D.N.; Haan, J.J. & Myers, G.T.
Object Type:
Article
System:
The UNT Digital Library
Advanced waste forms from spent nuclear fuel
More than one hundred spent nuclear fuel types, having an aggregate mass of more than 5000 metric tons (2700 metric tons of heavy metal), are stored by the United States Department of Energy. This paper proposes a method for converting this wide variety of fuel types into two waste forms for geologic disposal. The method is based on a molten salt electrorefining technique that was developed for conditioning the sodium-bonded, metallic fuel from the Experimental Breeder Reactor-II (EBR-II) for geologic disposal. The electrorefining method produces two stable, optionally actinide-free, high-level waste forms: an alloy formed from stainless steel, zirconium, and noble metal fission products, and a ceramic waste form containing the reactive metal fission products. Electrorefining and its accompanying head-end process are briefly described, and methods for isolating fission products and fabricating waste forms are discussed.
Date:
December 31, 1995
Creator:
Ackerman, J.P. & McPheeters, C.C.
Object Type:
Report
System:
The UNT Digital Library
Environmental impacts of ocean disposal of CO{sub 2}
This project has examined the impacts from the marine disposal of carbon dioxide based on the current state of knowledge.
Date:
December 31, 1995
Creator:
Adams, E.; Herzog, H.; Auerbach, D. & Caulfield, J.
Object Type:
Article
System:
The UNT Digital Library
Deflagration-induced pressure and temperature transients in a waste storage facility
This paper presents a study for a facility where a deflagration of flammable vapors takes place, and the generated pressure and temperature transients are analyzed to evaluate the pressure differentials induced on the various components of the facility to assesses their structural integrity. The temperature profiles are also analyzed to assess the qualification of the equipment that is required to operate during and after such an accident.
Date:
December 31, 1995
Creator:
Ades, M. J. & Polizzi, L. M.
Object Type:
Article
System:
The UNT Digital Library
Atomic structure of active sites in O{sub 2} reduction on Au(111)/Tl{sub ad} electrodes in acid and alkaline solutions
Surface x-ray scattering has been used to determine the structure of Tl adlayers on the Au(111) electrode surface during the course of 0{sub 2} reduction. 0. reduction is considerably catalyzed by Ti adlayers on Au(111). The half-wave potential is shifted to more positive values in the presence of the Ti adlayer. In both, acid and alkaline solutions TI causes a change in the reaction mechanism from a 2-ereduction to a 4e-reduction in a limited potential range. The in-plane X-ray diffraction measurements revealed that the close-packed rotated-hexagonal Ti phase, which exists in the potential range between -0.4V and the bulk TI deposition at {approx}{minus} 0.7V, has a lower activity for 0. reduction than the low-coverage phases in both solutions. It supports a 2e-reduction.0{sub 2} reduction does not change the TI coverage in this phase but causes a significant decrease of the in-plane diffracted intensity. The lower coverage phases which exist at more positive potentials, viz., aligned hexagonal in alkaline solution and patches of the (2 {times} 2)TI phase in acid solution, are conducive to a 4e-reduction. The diffraction intensity from these two phases, however, vanishes quickly during O{sub 2} reduction. It appears that the TI coverage remains on the surface unchanged. …
Date:
December 31, 1995
Creator:
Adzic, R. R. & Wang, J. X.
Object Type:
Article
System:
The UNT Digital Library
Intercooler Flow Path for Gas Turbines: CFD Design and Experiments
The Advanced Turbine Systems (ATS) program was created by the U.S. Department of Energy to develop ultra-high efficiency, environmentally superior, and cost competitive gas turbine systems for generating electricity. Intercooling or cooling of air between compressor stages is a feature under consideration in advanced cycles for the ATS. Intercooling entails cooling of air between the low pressure (LP) and high pressure (HP) compressor sections of the gas turbine. Lower air temperature entering the HP compressor decreases the air volume flow rate and hence, the compression work. Intercooling also lowers temperature at the HP discharge, thus allowing for more effective use of cooling air in the hot gas flow path.
Date:
December 31, 1995
Creator:
Agrawal, A. K.; Gollahalli, S. R. & Carter, F. L.
Object Type:
Article
System:
The UNT Digital Library
Report to users of ATLAS, December 1995
This report covers the following: status of ATLAS accelerator; highlights of recent research at ATLAS; research related concept for an Advanced Exotic Beam Facility on ATLAS; program advisory committee; and ATLAS user group executive committee. Research highlights are given for the following: APEX progress report; transport efficiency of the Argonne Fragment Mass Analyzer; collective motion in light polonium isotopes; angular correlation measurements for {sup 12}C(g.s.) + {sup 12}C(3{minus},9.64MeV) inelastic scattering; and the AYE-ball (Argonne-Yale-European gamma spectrometer) used to study the structure of nuclei far from stability.
Date:
December 1, 1995
Creator:
Ahmad, I. & Glagola, B.
Object Type:
Report
System:
The UNT Digital Library
A new look at positron production from heavy-ion collisions: Results from apex
A new solenoidal spectrometer, designed to study the production mechanism of electrons and positrons in heavy-ion collisions, has been constructed at Argonne National Laboratory. The spectrometer has been used to study the {sup 238}U + {sup 181}Ta system at 5.95, 6.10, and 6.30 MeV/u and the {sup 238}U + {sup 232}Th system at 5.95 MeV/u. These bombarding energies cover the energy region where previous experiments have reported sharp sum-energy lines. No evidence is found for sharp peaks in the present data. For the specific case of the isolated decay of a neutral particle of mass 1.4--2.1 MeV/c{sup 2} the upper limits on cross sections obtained from the present data are significantly less than the previously reported cross sections.
Date:
December 31, 1995
Creator:
Ahmad, I.; Back, B. B. & Austin, S. M.
Object Type:
Article
System:
The UNT Digital Library
The positron peak puzzle - recent results from APEX
Results are presented from a new experiment, APEX, designed to study the previously reported sharp lines in sum-energy spectra of positrons and electrons produced in collisions of very heavy ions. Data have been collected for {sup 238}U+{sup 181}Ta and {sup 238}U+{sup 232}Th. No evidence is found for narrow structures similar to those previously reported. For the specific case of the isolated decay of a neutral particle of mass 1.4-2.1 MeV/c{sup 2}, the upper limits on cross sections obtained are significantly less than previously reported. Data are also presented for internal pair conversion in {sup 206}Pb. These results are used to set limits for the possible contribution to the pair yield of a 1780 keV transition in {sup 238}U observed in heavy-ion gamma-ray coincidence measurements.
Date:
December 31, 1995
Creator:
Ahmad, I.; Back, B.B. & Kutschera, W.
Object Type:
Article
System:
The UNT Digital Library
Ash and pulverized coal deposition in combustors and gasifiers. Quarterly technical progress report, July 1--September 30, 1995
During this quarter, further progress has been made in accomplishing the objectives of the project. The computational model for simulating particle motions in turbulent flows has been further developed. The model was applied to the analysis of particle transport and deposition processes in a circular duct and in a plane recirculating region. A model for evaluating particle deposition rate in the presence of gravitational and electrical forces in turbulent flows formulated. Results concerning the deposition velocity of particles under various conditions were obtained. It is shown that the model predictions are in good agreement with the available experimental and digital simulation data. Experimental study of glass fiber transport and deposition rate is also being planned.
Date:
December 31, 1995
Creator:
Ahmadi, G.
Object Type:
Report
System:
The UNT Digital Library
Ash & pulverized coal deposition in combustors & gasifiers. Quarterly technical progress report, April 1, 1995--June 30, 1995
In the period of April 1, 1995 to June 30, 1995, a computational model for simulating particle motions turbulent flow condition is developed. The model was applied to the analysis of particle transport and deposition processes in a circular duct and in a plane recirculating region. The mean gas velocity and turbulence intensity fields were first estimated using the available experimental data, as well as those obtained from an earlier developed CFD code. A model for evaluating particle deposition rate in the presence of gravitational and electrical forces in turbulent flows was also formulated. Results concerning the deposition velocity of particles under various conditions were obtained. It was shown that the model predictions are in good agreement with the available experimental and digital simulation data. Experimental study of glass fiber transport and deposition rate is also initiated.
Date:
December 1, 1995
Creator:
Ahmadi, G.
Object Type:
Report
System:
The UNT Digital Library
Quick-start catalyzed methanol partial oxidation reformer
The catalytic methanol partial oxidation reformer described in this paper offers all the necessary attributes for use in transportation fuel cell systems. The bench-scale prototype methanol reformer developed at Argonne is a cylindrical reactor loaded with copper zinc oxide catalyst. Liquid methanol, along with a small amount of water, is injected as a fine spray into a flowing air stream, past an igniter onto the catalyst bed where the partial oxidation reaction takes place.
Date:
December 1, 1995
Creator:
Ahmed, S. & Kumar, R.
Object Type:
Article
System:
The UNT Digital Library
Thermal diffusivity imaging of continuous fiber ceramic composite materials and components
Continuous-fiber ceramic matrix composites (CFCCs) are currently being developed for various high-temperature applications, including use in advanced turbine engines. In such composites, the condition of the interfaces between the fibers and matrix or between laminae in a two-dimensional weave lay-up are critical to the mechanical and thermal behavior of the component. A nondestructive evaluation method that could be used to assess the interface condition and/or detect other `defects` has been developed at Argonne National Laboratory (ANL) and uses infrared thermal imaging to provide `single-shot` full- field quantitative measurement of the distribution of thermal diffusivity in large components. By applying digital filtering, interpolation, and least-squares-estimation techniques for noise reduction, shorter acquisition and analysis times have been achieved with submillimeter spatial resolution for materials with a wide range of `thermal thicknesses`. The system at ANL has been used to examine the effects of thermal shock, oxidation treatment, density variations, and variations in fiber coating in a full array of test specimens. In addition, actual subscale CFCC components of nonplanar geometries have been inspected for manufacturing-induced variations in thermal properties.
Date:
December 31, 1995
Creator:
Ahuja, S.; Ellingson, W.A.; Steckenrider, J.S. & King, S.
Object Type:
Article
System:
The UNT Digital Library