Access
Partner
UNT Libraries Government Documents Department
959
Oklahoma Historical Society
407
UNT Libraries Special Collections
72
Sterling Municipal Library
26
Carl Albert Congressional Research and Studies Center
21
UNT Libraries
21
Alvin Community College
12
Comanche Public Library
12
Rice University Woodson Research Center
11
San Antonio Public Library
11
74 More
Collection
Office of Scientific & Technical Information Technical Reports
853
Texas Digital Newspaper Program
318
Jim Argo Collection
255
Oklahoma Digital Newspaper Program
181
Tocker Foundation Grant
132
Chickasha Newspaper Collection
49
Texas State Publications
38
Congressional Research Service Reports
37
Altus Times-Democrat
26
The Baytown Sun
26
123 More
Country
Year
Month
Language
1,831 Matching Results
Results open in a new window/tab.
Characterization of amorphous carbon films grown by pulsed-laser deposition
Amorphous carbon (a-C) films grow via energetic processes such as pulsed-laser deposition (PLD). The cold-cathode electron emission properties of a-C are promising for flat-panel display and vacuum microelectronics technologies. These ultrahard films consist of a mixture of 3-fold and 4-fold coordinated carbon atoms, resulting in an amorphous material with diamond-like properties. The authors study the structures of a-C films grown at room temperature as a function of PLD energetics using x-ray reflectivity, Raman spectroscopy, high-resolution transmission electron microscopy, and Rutherford backscattering spectrometry. While an understanding of the electron emission mechanism in a-C films remains elusive, the onset of emission is typically preceded by conditioning where the material is stressed by an applied electric field. To simulate conditioning and assess its effect, the authors use the spatially-localized field and current of a scanning tunneling microscope tip. Scanning force microscopy shows that conditioning alters surface morphology and electronic structure. Spatially-resolved electron energy loss spectroscopy indicates that the predominant bonding configuration changes from predominantly 4-fold to 3-fold coordination.
Date:
September 1, 1998
Creator:
Siegal, M.P.; Tallant, D.R.; Barbour, J.C.; Provencio, P.N.; Martinez-Miranda, L.J. & DiNardo, N.J.
Object Type:
Report
System:
The UNT Digital Library
Characterization of commercial fiber optic connectors - Preliminary report
Several types of commercial fiber optic connectors were characterized for potential use in a Sandia designed Laser Diode Ignition (LDI) system. The characterization included optical performance while the connectors were subjected to the more dynamic environmental conditions experienced in weapons applications. The environmental testing included temperature cycling, random vibration, and mechanical shock. This report presents a performance assessment of the fiber optic connectors and fiber included in the characterization. The desirable design features are described for a fiber optic connector that must survive the dynamic environment of weapon systems. The more detailed performance of each connector type will be included as resources permit.
Date:
September 1, 1998
Creator:
Andrews, Larry A. & Williams, Randy J.
Object Type:
Report
System:
The UNT Digital Library
Characterization of hydrogeologic units using matrix properties, Yucca Mountain, Nevada
Determination of the suitability of Yucca Mountain, in southern Nevada, as a geologic repository for high-level radioactive waste requires the use of numerical flow and transport models. Input for these models includes parameters that describe hydrologic properties and the initial and boundary conditions for all rock materials within the unsaturated zone, as well as some of the upper rocks in the saturated zone. There are 30 hydrogeologic units in the unsaturated zone, and each unit is defined by limited ranges where a discrete volume of rock contains similar hydrogeologic properties. These hydrogeologic units can be easily located in space by using three-dimensional lithostratigraphic models based on relationships of the properties with the lithostratigraphy. Physical properties of bulk density, porosity, and particle density; flow properties of saturated hydraulic conductivity and moisture-retention characteristics; and the state variables (variables describing the current state of field conditions) of saturation and water potential were determined for each unit. Units were defined using (1) a data base developed from 4,892 rock samples collected from the coring of 23 shallow and 8 deep boreholes, (2) described lithostratigraphic boundaries and corresponding relations to porosity, (3) recognition of transition zones with pronounced changes in properties over short vertical distances, …
Date:
September 1, 1998
Creator:
Flint, L.E.
Object Type:
Report
System:
The UNT Digital Library
Characterization of the Sources and Concentrations of Formaldehyde and other volatile organic compounds in four new manufactured houses
The concentrations of formaldehyde, 52 individual volatile organic compounds (VOCs) and total VOCs (TVOC) were measured in four new manufactured houses on three occasions over a period of approximately nine months following completion of their construction. The houses were furnished, but unoccupied, model homes produced by a single U.S. manufacturer. Several of the houses incorporated interior finish materials with lower VOC emissions than standard materials. One house had a modified ventilation system. Ventilation rates were measured concurrently with the collection of air samples. A steady-state mass-balance model was used to calculate the area-specific emission rates of the target compounds and TVOC. The emissions of formaldehyde and VOCs from a specimen of plywood used as the floor sheeting were additionally quantified. The median formaldehyde concentration in the four houses was 37 parts-per-billion ( ppb). The formaldehyde concentrations were all less than the most restrictive guideline for this compound of 50 ppb. The concentrations of many of the target VOCs were low. Thirty-one of the VOCs had median concentrations that were at or below 1 ppb. Seven of the compounds were among the most abundant VOCs in all four houses. These compounds were alpha-pinene, beta-pinene, 3-carene, ethylene glycol, hexanal, 2-butanone, and acetic …
Date:
September 1, 1998
Creator:
Hodgson, A. T.; Beal, D. & Chandra, S.
Object Type:
Article
System:
The UNT Digital Library
Chemical and Metallurgy Research (CMR) Sample Tracking System Design Document
The purpose of this document is to describe the system architecture of the Chemical and Metallurgy Research (CMR) Sample Tracking System at Los Alamos National Laboratory. During the course of the document observations are made concerning the objectives, constraints and limitations, technical approaches, and the technical deliverables.
Date:
September 1, 1998
Creator:
Bargelski, C. J. & Berrett, D. E.
Object Type:
Report
System:
The UNT Digital Library
Chemogram, September 1998
Monthly newsletter of the Texas Agricultural Extension Service discussing research, recommendations, and other information related to pesticide regulation and use in Texas.
Date:
September 1998
Creator:
Texas Agricultural Extension Service
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History
Chickasha Daily Express (Chickasha, Okla.), Ed. 1 Tuesday, September 1, 1998
Daily newspaper from Chickasha, Oklahoma that includes local, state, and national news along with advertising.
Date:
September 1, 1998
Creator:
Bush, Kent
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
Choosing a Job
Workbook that can be used to evaluate the best job for you and your skillsets.
Date:
September 1998
Creator:
Texas Rehabilitation Commission
Object Type:
Pamphlet
System:
The Portal to Texas History
The Christian Chronicle (Oklahoma City, Okla.), Vol. 55, No. 9, Ed. 1 Tuesday, September 1, 1998
Monthly newspaper from Oklahoma City, Oklahoma that includes news and information about the Churches of Christ along with advertising.
Date:
September 1, 1998
Creator:
McBride, Bailey & Shipp, Glover
Object Type:
Newspaper
System:
The Portal to Texas History
Church & Synagogue Libraries, Volume 32, Number [2], September/October 1998
Bimonthly publication of the Church and Synagogue Library Association, containing news and events related to the organization and its members, reviews of books and other materials, and stories of interest to the management of congregational libraries.
Date:
September 1998
Creator:
Church and Synagogue Library Association
Object Type:
Journal/Magazine/Newsletter
System:
The UNT Digital Library
[Clipping: The Women Airforce Service Pilots: WASP Fly 60 Million Miles]
Photocopy of a magazine article about the creation and the training of the WASPs as well as their accomplishments in women's aviation.
Date:
September 1998
Creator:
Landdeck, Kate
Object Type:
Clipping
System:
The Portal to Texas History
Cloning and sequencing of the trpE gene from Arthrobacter globiformis ATCC 8010 and several related subsurface Arthrobacter isolates
Tryptophan dependent mutants of Arthrobacter globiformis ATCC 8010 were isolated and trp genes were cloned by complementation and marker rescue of the auxotrophic strains. Rescue studies and preliminary sequence analysis reveal that at least the genes trpE, trpC, and trpB are clustered together in this organism. In addition, sequence analysis of the entire trpE gene, which encodes component I of anthranilate synthase, is described. Segments of the trpE gene from 17 subsurface isolates of Arthrobacter sp. were amplified by PCR and sequenced. The partial trpE sequences from the various strains were aligned and subjected to phylogenetic analysis. The data suggest that in addition to single base changes, recombination and genetic exchange play a major role in the evolution of the Arthrobacter genome.
Date:
September 1, 1998
Creator:
Chernova, T.; Viswanathan, V.K.; Austria, N. & Nichols, B.P.
Object Type:
Report
System:
The UNT Digital Library
Closure Report for Corrective Action Unit 404: Roller Coaster Sewage Lagoons and North Disposal Trench, Tonopah Test Range, Nevada
None
Date:
September 1, 1998
Creator:
Madsen, Dave
Object Type:
Report
System:
The UNT Digital Library
Closure Report for Corrective Action Unit 404: Roller Coaster Sewage Lagoons and North Disposal Trench, Tonopah Test Range, Nevada with ROTC 1, Revision 0
This Closure Report provides the documentation for closure of the Roller Coaster Sewage Lagoons and North Disposal Trench Comective Action Unit (CAU) 404. CAU 404 consists of the Roller Coaster Sewage Lagoons (Corrective Action Site [CAS] TA-03-O01-TA-RC) and the North Disposal Trench (CAS TA-21-001-TA-RC). The site is located on the Tonopah Test Range, approximately 225 kilometers (km) (140 miles [mi]) northwest ofLas Vegas, Nevada. . The sewage lagoons received ~quid sanitary waste horn the Operation Roller Coaster Man Camp in 1963 and debris from subsequent range and construction cleanup activities. The debris and ordnance was subsequently removed and properly dispos~, however, pesticides were detected in soil samples born the bottom of the lagoons above the U,S. Environmental Protection Agency Region IX Prelimimuy Remediation Goals (EPA 1996). . The North Disposal Trench was excavated in 1963. Debris from the man camp and subsequent range and construction cleanup activities was placed in the trench. Investigation results indicated that no constituents of concern were detected in soil samples collected from the trench. Remedial alternative proposed in the Comctive Action Decision Document (CADD) fm the site was “Covering” (DOE, 1997a). The Nevada Division of”Enviromnental Protection (NDEP)-approved Correction Action Plan (CAP) proposed the “Covering” niethodology …
Date:
September 1, 1998
Creator:
Kidman, Lynn
Object Type:
Report
System:
The UNT Digital Library
Collector for recovering gallium from weapons plutonium
Currently, the separation of gallium from weapons plutonium involves the use of aqueous processing using either solvent extraction of ion exchange. However, this process generates significant quantities of liquid radioactive wastes. A Thermally Induced Gallium Removal process, or TIGR, developed by researchers at Los Alamos National Laboratories, is a simpler alternative to aqueous processing. This research examined this process, and the behavior of gallium suboxide, a vapor that is swept away by passing hydrogen/argon over gallium trioxide/plutonium oxide heated at 1100 C during the TIGR process. Through experimental procedures, efforts were made to prevent the deposition of corrosive gallium onto furnace and vent surfaces. Experimental procedures included three options for gallium removal and collection: (1) collection of gallium suboxide through use of a cold finger; (2) collection by in situ air oxidation; and (3) collection of gallium on copper. Results conclude all three collection mechanisms are feasible. In addition, gallium trioxide exists in three crystalline forms, and each form was encountered during each experiment, and that each form will have a different reactivity.
Date:
September 1, 1998
Creator:
Philip, C. V.; Anthony, R. G. & Chokkaram, S.
Object Type:
Report
System:
The UNT Digital Library
College Bound American Indian Math and Science Enrichment Program (AIMS). Final report
Southwestern Indian Polytechnic Institute (SIPI), was founded in 1971 and is located on 164 acres in northwest Albuquerque, New Mexico in the center of New Mexico`s agricultural and high-tech corridors. SIPI became accredited as a community college in 1993, serves Native Americans nationwide, and is governed by a nationally-tribally appointed Board of Regents (Jicarilla Apache, Joint Oklahoma Tribes, Mescalero Apache, Navajo Nation-Arizona, Navajo Nation-New Mexico, Ten Southern Pueblos, and Eight Northern Pueblos, Southern Ute, Inter-tribal Council of Arizona, and Oglala Sioux). In 1993, The US Department of Education, TRIO Programs no longer funded the Southwestern Indian Polytechnic Institute (SIPI) Summer Math and Science Enrichment Program. However, with US Department of Energy funding SIPI was able to continue service to the Native American community under the new title of College Bound American Indian Math and Science (AIMS) Enrichment Program. This new program continued the goals and objectives of the TRIO program with an expanded focus that included students from more Native American communities nationwide. The program also interfaced with a teacher enrichment program (Rural American Indian Science Education-RAISE) sponsored by the Bureau of Indian Affairs and Sandia National Labs (SNL). SIPI in collaboration with Sandia National Laboratories and Lawrence Livermore National …
Date:
September 1, 1998
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Comparison of advanced distillation control methods. Fourth annual report
Detailed dynamic simulations of three industrial columns (a propylene/propane splitter, a xylene/toluene column, and a depropanizer) have been used to evaluate configuration selection for single-ended and dual-composition control as well as compare conventional and advanced control approaches. For each case considered, the controllers were tuned by using setpoint changes and tested using feed composition upsets. Proportional Integral (PI) control performance was used to evaluate the configuration selection problem. For single ended control, the energy balance configuration was found to yield the best performance. For dual composition control, nine configurations were considered. It was determined that in order to identify the optimum configuration, detailed testing using dynamic simulation is required. The optimum configurations were used to evaluate the control performance of conventional PI controllers, DMC (Dynamic Matrix Control), PMBC (Process Model Based Control), and ANN (Artificial Neural Networks) control. It was determined that DMC works best when one product is much more important than the other while PI was superior when both products were equally important. PMBC and ANN were not found to offer significant advantages over PI and DMC.
Date:
September 1998
Creator:
Riggs, J. B.
Object Type:
Report
System:
The UNT Digital Library
[A comprehensive signature biomarker analysis of the in-situ viable biomass, community composition, and nutritional status attributes of deep subsurface microbiota]. Final report
The TAN sites contains subsurface sediment contaminated with trichloroethylene (TC). A suite of microbiological analyses, including ester-linked phospholipid fatty acid (PLFA) analysis, were performed to ascertain the microbial ecology associated with TCE degradation processes. The objective of the PLFA analyses were: (1) to determine the distribution of viable microbes throughout a vertical depth profile through the TCE plume, (2) determine the community composition of the viable extant microbiota and (3) relate the data derived from the PLFA analyses to other measures of the in situ microbiota as well as to the presence of TCE degradative products.
Date:
September 1, 1998
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Construction of Effective Electromagnetic Currents for Two-Body Quasipotential Equations
A systematic algebraic approach for the construction of effective electro-magnetic currents consistent with relativistic two-body quasipotential equations is presented. This approach generalizes the Mandelstam formalism and applies it to a generic quasipotential reduction method. The use of Ward-Takahashi identities for the effective currents guarantees conservation of current matrix elements involving any combination of bound and scattering states. This approach is shown to reproduce previous results for current matrix elements for the particular cases of the Gross and Blankenbecler-Sugar equations. A generic method of truncation of the quasipotential effective current with respect to the number of boson exchanges is introduced.
Date:
September 1, 1998
Creator:
Krioukov, Dmitri
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Continued development of modeling tools and theory for rf heating. Final report
The work performed during the grant has been reported long before this date, specifically in: (1) the grant`s annual performance report for 1991, MRC/WDC-R-277; (2) the published AIP Conference Proceedings {number_sign}244, Radio Frequency Power in Plasmas, Charleston, SC 1991, ``Evaluation of Wave Dispersion, Mode-Conversion, and Damping for ECRH with Exact Relativistic Corrections,`` by D.N. Smithe and P.L. Colestock; and (3) an unpublished paper entitled ``Temperature Anisotropy and Rotation Upgrades to the ICRF Modules in SNAP and TRANSP``, presented at the 1992 ICRF Modeling and Theory Workshop, at the Princeton Plasma Physics Laboratory. This final report contains copies of number (1). The specifics of the grant`s final months` activities, which to the authors recollection have never been reported to the DOE, are as follows. The original grant, which was to terminate August 15, 1991, was extended without additional funds to October 31, 1992. The primary reason for the extension was to permit attendance at the 1992 ICRF Modeling and Theory Workshop at the Princeton Plasma Physics Laboratory (PPPL), which was finally held August 17--18, 1992, after having been rescheduled several times during the summer of 1992. The body of this report contains copies of the 1991 annual report, which gives detailed …
Date:
September 1, 1998
Creator:
Smithe, D.N.
Object Type:
Report
System:
The UNT Digital Library
Controlling fluctuations and transport in the reversed field pinch with edge current drive and plasma biasing
Two techniques are employed in the Madison Symmetric Torus (MST) to test and control different aspects of fluctuation induced transport in the Reversed Field Pinch (RFP). Auxiliary edge currents are driven along the magnetic field to modify magnetic fluctuations, and the particle and energy transport associated with them. In addition, strong edge flows are produced by plasma biasing. Their effect on electrostatic fluctuations and the associated particle losses is studied. Both techniques are accomplished using miniature insertable plasma sources that are biased negatively to inject electrons. This type of emissive electrode is shown to reliably produce intense, directional current without significant contamination by impurities. The two most important conclusions derived from these studies are that the collective modes resonant at the reversal surface play a role in global plasma confinement, and that these modes can be controlled by modifying the parallel current profile outside of the reversal surface. This confirms predictions based on magnetohydrodynamic (MHD) simulations that auxiliary current drive in the sense to flatten the parallel current profile can be successful in controlling magnetic fluctuations in the RFP. However, these studies expand the group of magnetic modes believed to cause transport in MST and suggest that current profile control …
Date:
September 1, 1998
Creator:
Craig, D.J.G.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Conversion ratios for the foodstuffs and biota environmental surveillance program
The foodstuffs and biota monitoring programs at Los Alamos National Laboratory (LANL) comprises two of the five Environmental Surveillance Programs mandated by Department of Energy Orders, and LANL has conducted these studies since the early 1970s (ESR 1997). Because foodstuffs and biota commonly contain very small amounts of radionuclides in the edible portions of the tissue, samples are commonly ashed to concentrate the radioisotope(s) in order to adequately detect the element; therefore, results are usually reported in units per gram of ash. To compensate for the differing water contents in various matrices (gram of ash are usually two to four orders of magnitude higher than live weights), units in gram of ash are converted to units of gram of dry material--the standard representation of data. Further, results in units per gram dry weight are converted to units of wet weight in order to estimate radiation doses to the public from the ingestion of these products. This paper reports the mean ash to dry and dry to wet weight moisture conversion ratios for a variety of foodstuffs and biota that have been collected as part of the Environmental Surveillance Program at LANL from 1990 to present.
Date:
September 1, 1998
Creator:
Fresquez, P.R. & Ferenbaugh, J.K.
Object Type:
Report
System:
The UNT Digital Library
Cookoff of energetic materials
An overview of cookoff modeling at Sandia National Laboratories is presented aimed at assessing the violence of reaction following cookoff of confined energetic materials. During cookoff, the response of energetic materials is known to involve coupled thermal/chemical/mechanical processes which induce thermal damage to the energetic material prior to the onset of ignition. These damaged states enhance shock sensitivity and lead to conditions favoring self-supported accelerated combustion. Thus, the level of violence depends on the competition between pressure buildup and stress release due to the loss of confinement. To model these complex processes, finite element-based analysis capabilities are being developed which can resolve coupled heat transfer with chemistry, quasi-static structural mechanics and dynamic response. Numerical simulations that assess the level of violence demonstrate the importance of determining material damage in pre- and post-ignition cookoff events.
Date:
September 1, 1998
Creator:
Baer, M. R.; Hobbs, M. L.; Gross, R. J. & Schmitt, R. G.
Object Type:
Article
System:
The UNT Digital Library
Cooperative Control of a Squad of Mobile Vehicles
Tasks such as the localization of chemical sources, demining, perimeter control, surveillance and search and rescue missions are usually performed by teams of people. At least conceptually, large groups of relatively cheap mobile vehicles outfitted with sensors should be able to automatically accomplish some of these tasks. Sandia National Labs is currently developing a swarm of semi-autonomous all terrain vehicles for remote cooperative sensing applications. This paper will describe the capabilities of this system and outline some of its possible applications. Cooperative control and sensing strategies will also be described. Eight Roving All Terrain Lunar Explorer Rovers (RATLERs) have been built at Sandia as a test platform for cooperative control and sensing applications. This paper will first describe the hardware capabilities of the RATLER system. Then it will describe the basic control algorithm for GPS based navigation and obstacle avoidance. A higher level cooperative control task will then be described.
Date:
September 1, 1998
Creator:
Lewis, C.; Feddema, J. & Klarer, P.
Object Type:
Article
System:
The UNT Digital Library