Partner
UNT Libraries Government Documents Department
314
Oklahoma Historical Society
57
Abilene Christian University Library
50
UNT Libraries Special Collections
27
Sterling Municipal Library
10
Carl Albert Congressional Research and Studies Center
7
San Antonio Public Library
6
Patrick Heath Public Library
5
Virgil and Josephine Gordon Memorial Library
5
Comanche Public Library
4
52 More
Collection
Office of Scientific & Technical Information Technical Reports
257
Texas Digital Newspaper Program
121
Tocker Foundation Grant
61
Oklahoma Digital Newspaper Program
58
Abilene Library Consortium
55
ACU Summit Lecture Series
47
Government Accountability Office Reports
36
Altus Times-Democrat
10
The Baytown Sun
10
Chickasha Newspaper Collection
10
92 More
States
Year
Month
Day
Language
Measurement of the Fundamental Parameters for the Film-Rupture/Oxidation Mechanism
Identification of the mechanism responsible for primary water stress corrosion cracking (PWSCC) in nickel-base alloys is a controversial topic. Numerous mechanisms, including the film-rupture/oxidation (i.e., slip-oxidation or slip-dissolution) mechanism, have been proposed to explain PWSCC. According to this mechanism, the observed sensitivity of PWSCC to material and environmental factors may be explained by the combined effects of repassivation kinetics, oxide rupture strain, and crack tip strain rate (which includes creep). Previous research has shown that increasing the Cr content of Ni-9%Fe-Cr from 16 to 30 wt% strongly decreases PWSCC susceptibility. Consequently, measurements of these three fundamental parameters (repassivation, oxide rupture, and creep) were performed as a function of Cr content, and SCC crack growth rates were predicted on the basis of the resulting data. This paper illustrates that considering these three parameters concurrently may contribute to the understanding of Cr effects on PWSCC of Ni-base alloys. However, it is not clear whether the film-rupture/oxidation mechanism can adequately predict the observed crack growth rates for Alloy 600 at 338 C.
Date:
April 23, 1999
Creator:
Attanasio, S. A.; Fish, J. S.; Morton, D. S.; Rosecrans, P. M.; Was, G. S.; Wilkening, W. W. et al.
Object Type:
Article
System:
The UNT Digital Library
Measuring parameters of large-aperture crystals used for generating optical harmonics
The purpose of this project was to develop tools for understanding the influence of crystal quality and crystal mounting on harmonic-generation efficiency at high irradiance. Measuring the homogeneity of crystals interferometrically, making detailed physics calculations of conversion efficiency, performing finite- element modeling of mounted crystals, and designing a new optical metrology tool were key elements in obtaining that understanding. For this work, we used the following frequency-tripling scheme: type I second- harmonic generation followed by type II sum-frequency mixing of the residual fundamental and the second harmonic light. The doubler was potassium dihydrogen phosphate (KDP), and the tripler was deuterated KDP (KD*P). With this scheme, near-infrared light (1053 nm) can be frequency tripled (to 351 nm) at high efficiency (theoretically >90%) for high irradiance (>3 GW/cm²). Spatial variations in the birefringence of the large crystals studied here (37 to 41 cm square by about 1 cm thick) imply that the ideal phase-matching orientation of the crystal with respect to the incident laser beam varies across the crystal. We have shown that phase-measuring interferometry can be used to measure these spatial variations. We observed transmitted wavefront differences between orthogonally polarized interferograms of {lambda}/50 to {lambda}/100, which correspond to index variations of …
Date:
February 23, 1999
Creator:
Auerbach, J. M.; English, R. E., Jr.; Hibbard, R. L.; Michie, R. B.; Norton, M. A.; Perfect, S. A. et al.
Object Type:
Report
System:
The UNT Digital Library
Proton radiography as a means of material characterization
The authors describe how protons with energies of 800 MeV or greater can be used as radiographic probes for material characterization. A feature which distinguishes protons from x-rays is their charge, which results in multiple Coulomb scattering effects in proton radiographs. Magnetic lensing can ameliorate these effects and even allow mixed substances to be disentangled. They illustrate some of these effects using 800 MeV protons radiographs of a composite step wedge composed of Aluminum, Foam, and Graphite. They discuss how proton radiographs must be manipulated in order to use standard tomographic reconstruction algorithms. They conclude with a brief description of an upcoming experiment, which is performed at Brookhaven National Laboratory at 25 GeV.
Date:
June 23, 1999
Creator:
Aufderheide, M. B.; Barnes, P. D.; Bionta, R. M.; Hartouni, E. P.; Morris, C. L.; Park, H. S. et al.
Object Type:
Article
System:
The UNT Digital Library
Waste retrieval sluicing system campaign number 1 solids volume transferred calculation
This calculation has been prepared to document the volume of sludge removed from tank 241-C-106 during Waste Retrieval Sluicing System (WRSS) Sluicing Campaign No.1. This calculation will be updated, if necessary, to incorporate new data. This calculation supports the declaration of completion of WRSS Campaign No.1 and, as such, is also the documentation for completion of Performance Agreement TWR 1.2.1, C-106 Sluicing Performance Expectations. It documents the performance of all the appropriate tank 241-C-106 mass transfer verifications, evaluations, and appropriate adjustments discussed in HNF-SD-WM-PROC-021, Chapter 23, ''Process Engineering Calculations for Tank 241-C-106 Sluicing and Retrieval''.
Date:
June 23, 1999
Creator:
BAILEY, J.W.
Object Type:
Report
System:
The UNT Digital Library
WRSS jumper leak assessment
The purpose of this assessment is: (1) to assemble and document the facts associated with three recently installed jumpers which have leaked either during actual process operation or during post installation testing; (2) to describe the corrective actions taken and to identify any process improvements which need to be implemented in the Hanford jumper design and installation activities; and (3) to document WRSS jumper leak lessons learned for use by future projects and other jumper design, fabrication, and installation activities.
Date:
June 23, 1999
Creator:
BAILEY, J.W.
Object Type:
Report
System:
The UNT Digital Library
Data quality objectives for TWRS privatization phase 1: tank waste transfer control
The Phase 1 privatization contract (DOE-RL 1996) requires that the Project Hanford Management Contractors, on behalf of the U.S. Department of Energy, Richland Operations Office, deliver waste feed in appropriate quantities and composition on schedule. The Feed Process Management Team (FPMT) was created with responsibility for establishing requirements, identifying and recommending baseline change control, assuring configuration management of tank contents (e.g., feed pedigrees), and requiring understanding among the various TWRS elements so the right feed is produced on schedule (Boston 1996). The FPMT has charged the Double Shell Tank (DST) Waste Inventory Control (WIC) (LMHC 1997) group to develop and implement the waste configuration control needed to insure that our ability to deliver feed on schedule is not adversely impacted. The WIC group, which has representatives from engineering, environmental, operations, and waste feed delivery, reviews proposed waste transfers and technical issues affecting the TWRS waste inventory. The WIC group either approves proposed transfers or, if a unanimous decision is not obtained, elevates approval to the FPMT. A representative from the FPMT is present at the WIC group meetings where waste transfer approvals are decided, and WIC relays information to the FPMT as needed. The TWRS operations include waste inventory control, …
Date:
June 23, 1999
Creator:
BANNING, D.L.
Object Type:
Report
System:
The UNT Digital Library
Tank 241-Z-361 vapor sampling and analysis plan
Tank 241-Z-361 is identified in the Hanford Federal Facility Agreement and Consent Order (commonly referred to as the Tri-Party Agreement), Appendix C, (Ecology et al. 1994) as a unit to be remediated under the authority of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). As such, the U.S. Environmental Protection Agency will serve as the lead regulatory agency for remediation of this tank under the CERCLA process. At the time this unit was identified as a CERCLA site under the Tri-Party Agreement, it was placed within the 200-ZP-2 Operable Unit. In 1997, The Tri-parties redefined 200 Area Operable Units into waste groupings (Waste Site Grouping for 200 Areas Soils Investigations [DOE-RL 1992 and 1997]). A waste group contains waste sites that share similarities in geological conditions, function, and types of waste received. Tank 241-Z-361 is identified within the CERCLA Plutonium/Organic-rich Process Condensate/Process Waste Group (DOE-RL 1992). The Plutonium/Organic-rich Process Condensate/Process Waste Group has been prioritized for remediation beginning in the year 2004. Results of Tank 216-Z-361 sampling and analysis described in this Sampling and Analysis Plan (SAP) and in the SAP for sludge sampling (to be developed) will determine whether expedited response actions are required before 2004 …
Date:
February 23, 1999
Creator:
BANNING, D.L.
Object Type:
Report
System:
The UNT Digital Library
Engineering safety evaluation for 22 ton steel disposal box lifting bail design
The objective of this analysis is to design and analyze the lifting bail of the 22 Ton Steel Waste Disposal Box (SWDB). The new design takes the original lifting bail and adds a hinge allowing the top portion of the bail to fold over towards the lid.
Date:
November 23, 1999
Creator:
BOEHNKE, W.M.
Object Type:
Report
System:
The UNT Digital Library
Updated calculations of the reach of Fermilab Tevatron upgrades for Higgs Bosons in the MSSM, mSUGRA, and mGMSB models
One of the crucial predictions of supersymmetric models that reduce to the Minimal Supersymmetric Standard Model (MSSM) at the weak scale is that the lightest Higgs scalar should have mass m{sub h} {approx_lt} 125-130 GeV[1]. Recent results on the reach of Fermilab Tevatron upgrades for Standard Model (SM) Higgs bosons show that masses of order 120-180 GeV may be probed [2, 3, 4, 5], depending on integrated luminosity, detector performance and signal and background modeling. Thus, the discovery of a Higgs boson (or a new limit of around 120-130 GeV on its mass) will severely constrain supersymmetric models as well. In this report, we update previous calculations made by our group [6] pertaining to the reach of Fermilab Tevatron upgrades for Higgs bosons in supersymmetric models. We present reach results for SUSY Higgs bosons within the MSSM, the minimal Supergravity model (mSUGRA) and in the minimal Gauge Mediated SUSY Breaking model (mGMSB). In this update, 95% CL exclusion contours and 5{sigma} discovery contours are presented for integrated luminosity values of 2, 5 and 20 fb{sup {minus}1}.
Date:
April 23, 1999
Creator:
Baer, H.; Harris, B. W. & Tata, X.
Object Type:
Article
System:
The UNT Digital Library
Development of ceramic membranes for conversion of methane into syngas.
The abundantly available natural gas (mostly methane) discovered in remote areas has stimulated considerable research on upgrading this gas to high-value-added clean-burning fuels such as dimethyl ether and alcohols and to pollution-fighting fuel additives. Of the two routes to convert methane to valuable products, direct and indirect, the indirect route involving partial oxidation of methane to syngas (a mixture of CO and H{sub 2}) is preferred. Syngas is used as feedstock to produce a variety of petrochemicals and transportation fuels. A mixed-conducting dense ceramic membrane was developed from Sr-Fe-Co oxide. Extruded and sintered tubes of SrFeCoO{sub 0.5}O{sub x} have been evaluated in a reactor operating at {approx}850 C for conversion of methane into syngas in the presence of a reforming catalyst. Some of the reactor tubes have been run for more than 1000 h, and methane conversion efficiencies of {approx}98% and CO selectivities of >96% were observed.
Date:
September 23, 1999
Creator:
Balachandran, U. & Ma, B.
Object Type:
Article
System:
The UNT Digital Library
Critical current densities in Bi-2223 sinter forgings.
(Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Bi-2223) bars, prepared by sinter forging, exhibited good phase purity and strong textures with the c axes of the Bi-2223 grains parallel to the forging direction. The initial zero-field critical current density (J{sub c}) of the bars was 10{sup 3} A/cm{sup 2}, but because the forged bars were uncoated, this value decreased with repeated thermal cycling. J{sub c} as a function of applied magnetic field magnitude and direction roughly followed the dependencies exhibited by Ag-sheathed Bi-2223 tapes, but the forged bars were more strongly dependent on field strength and less strongly dependent on field angle.
Date:
July 23, 1999
Creator:
Balachandran, U.; Fisher, B. L.; Goretta, K. C.; Harris, N. C. & Murayama, N.
Object Type:
Article
System:
The UNT Digital Library
29th Annual PolyMAC Meeting: Book of Abstracts
A sixteen-run, Resolution IV, fractional factorial screening design has been used to evaluate the relative significance of seven independent material and process variables for an electrically deposited commercial acrylic paint. A Resolution IV design was chosen so that variable interactions could be detected without any interference from the effects of the variables themselves. Because resource limitations did not permit use of a Resolution V design, the two-way interactions were confounded with one another in groups of three, which unfortunately made interpretation of the results more complicated. Each design point was replicated once and a pair of centerpoints were run at the beginning, in the middle and at the end of the design points. A total of 38 test panels were prepared. Independent variables used in this experiment were total charge, current density, mixer speed, silica content, crossover point, temperature and solids fraction. The magnitude of each independent variable's effect on the dependent response variables was estimated by fitting a first-order model with two-way interaction terms. Three-way interactions were assumed to be insignificant. Interaction confounding was eliminated by using the significance of the independent variables to determine which of the three possible interactions was significant. Data analysis was performed using the …
Date:
July 23, 1999
Creator:
Balazs, B.
Object Type:
Report
System:
The UNT Digital Library
Toward Net Energy Buildings: Design, Construction, and Performance of the Grand Canyon House
The Grand Canyon house is a joint project of the DOE's National Renewable Energy Laboratory and the U.S. National Park Service and is part of the International Energy Agency Solar Heating and Cooling Programme Task 13 (Advanced Solar Low-Energy Buildings). Energy consumption of the house, designed using a whole-building low-energy approach, was reduced by 75% compared to an equivalent house built in accordance with American Building Officials Model Energy Code and the Home Energy Rating System criteria.
Date:
June 23, 1999
Creator:
Balcomb, J. D.; Hancock, C. E. & Barker, G.
Object Type:
Report
System:
The UNT Digital Library
Electronic Sputtering of Solids by Slow, Highly Charged Ions: Fundamentals and Applications
Characterization tools have been developed to study the performance characteristics and reliability of surface micromachined actuators. These tools include (1) the ability to electrically stimulate or stress the actuator, (2) the capability to visually inspect the devices in operation, (3) a method for capturing operational information, and (4) a method to extract performance characteristics from the operational information. Additionally, a novel test structure has been developed to measure electrostatic forces developed by a comb drive actuator.
Date:
July 23, 1999
Creator:
Banks, J. C.; Barnes, A. V.; Doyle, B. L.; Hamza, A. V.; Machicoane, G. A.; McDonald, J. W. et al.
Object Type:
Article
System:
The UNT Digital Library
Quantitative Analysis with Heavy Ion E-TOF ERD
Heavy ion TOF ERD combined with energy detection (E-TOF-ERD) is a powerful analytical technique taking advantage of the following facts: the scattering cross section is usually very high ({approximately}10{sup {minus}21} cm{sup 2}/sr) compared to regular He RBS ({approximately}10{sup {minus}25} cm{sup 2}/sr), contrary to what happens with the energy resolution in ordinary surface solid barrier detectors, time resolution is almost independent of the atomic mass of the detected element, and the detection in coincidence of time and energy signals allows for the mass separation of overlapping signals with the same energy (or time of flight). Measurements on several oxides have been performed with the E-TOF-ERD set up at Sandia National Laboratories using an incident beam of 10-15 MeV Au. The information on the composition of the sample is obtained from the time domain spectrum, which is converted to energy domain, and then, using existing software codes, the analysis is performed. During the quantification of the results, they have found problems related to the interaction of the beam with the sample and to the tabulated values of the stopping powers for heavy ions.
Date:
July 23, 1999
Creator:
Banks, J.C.; Doyle, B.L. & Font, A. Climent
Object Type:
Article
System:
The UNT Digital Library
Theory of the equation of state of hot dense matter
Ab initio molecular dynamics calculations are adapted to treat dense plasmas for temperatures exceeding the electronic Fermi temperature. Extended electronic states are obtained in a plane wave basis by using pseudopotentials for the ion cores in the local density approximation to density functional theory. The method reduces to conventional first principles molecular dynamics at low temperatures with the expected high level of accuracy. The occurrence of thermally excited ion cores at high temperatures is treated by means of final state pseudopotentials. The method is applied to the shock compression Hugoniot equation of state for aluminum. Good agreement with experiment is found for temperatures ranging from zero through 105K.
Date:
July 23, 1999
Creator:
Barbee, T W; Surh, M & Yang, L H
Object Type:
Article
System:
The UNT Digital Library
Effects of Hydrogen in the Annealing Environment on Photoluminescence from Si Nanoparticles in SiO(2)
The role of hydrogen in enhancing the photoluminescence (PL) yield observed from Si nanocrystals embedded in SiO{sub 2} has been studied. SiO{sub 2} thermal oxides and bulk fused silica samples have been implanted with Si and subsequently annealed in various ambients including hydrogen or deuterium forming gases (Ar+4%H{sub 2} or Ar+4%D{sub 2}) or pure Ar. Results are presented for annealing at temperatures between 200 and 1100 C. Depth and concentration profiles of H and D at various stages of processing have been measured using elastic recoil detection. Hydrogen or deuterium is observed in the bulk after annealing in forming gas but not after high temperature (1100 C) anneals in Ar. The presence of hydrogen dramatically increases the broad PL band centered in the near-infrared after annealing at 1100 C but has almost no effect on the PL spectral distribution. Hydrogen is found to selectively trap in the region where Si nanocrystals are formed, consistent with a model of H passivating surface states at the Si/SiO{sub 2} interface that leads to enhanced PL. The thermal stability of the trapped H and the PL yield observed after a high temperature anneal have been studied. The hydrogen concentration and PL yield are unchanged …
Date:
March 23, 1999
Creator:
Barbour, J. C.; Budai, J. D.; Hembree, D. M.; Meldrum, A.; White, C. W. & Withrow, S. P.
Object Type:
Article
System:
The UNT Digital Library
News Bulletin (Castroville, Tex.), Vol. 41, No. 38, Ed. 1 Thursday, September 23, 1999
Weekly newspaper from Castroville, Texas that includes local, state, and national news along with extensive advertising.
Date:
September 23, 1999
Creator:
Barnes, Thomas
Object Type:
Newspaper
System:
The Portal to Texas History
News Bulletin (Castroville, Tex.), Vol. 41, No. 51, Ed. 1 Thursday, December 23, 1999
Weekly newspaper from Castroville, Texas that includes local, state, and national news along with extensive advertising.
Date:
December 23, 1999
Creator:
Barnes, Thomas
Object Type:
Newspaper
System:
The Portal to Texas History
Churches Can Care for Senior Adults - A Senior Adult Tidal Wave is Coming!
Lecture given Tuesday, February 23, 1999, 8:30 AM at Abilene Christian University
Date:
February 23, 1999
Creator:
Barnhill, Bob
Object Type:
Sound
System:
The Portal to Texas History
Churches Can Care for Senior Adults - Churches Can Provide for Senior Adults
Lecture given Tuesday, February 23, 1999, 3:30 PM at Abilene Christian University
Date:
February 23, 1999
Creator:
Barnhill, Bob
Object Type:
Sound
System:
The Portal to Texas History
Churches Can Care for Senior Adults - The Three Basic Needs of Senior Adults
Lecture given Tuesday, February 23, 1999, 11:00 AM at Abilene Christian University
Date:
February 23, 1999
Creator:
Barnhill, Bob
Object Type:
Sound
System:
The Portal to Texas History
High-accuracy calibration of an adaptive optics system using a phase shifting diffraction interferometer
A phase-shifting diffraction interferometer (PSDI) has been integrated into an adaptive optics (AO) system developed by LLNL for use on the three meter Shane telescope at Lick Observatory. The interferometer is an all fiber optic design, which is extremely compact. It is useful for calibrating the control sensors, measuring the aberrations of the entire AO optical train, and measuring the influence functions of the individual actuators on the deformable mirror. The PSDI is particularly well suited for this application because it measures converging, quasi-spherical wavefronts, such as are produced by an AO imaging system. Thus, a PSDI can be used to measure the aberrations of the entire AO system, in-situ and without errors introduced by auxiliary optics. This provides an extremely accurate measurement ({approximately} 5 nm RMS) of the optical properties of the AO system.
Date:
June 23, 1999
Creator:
Bauman, B. J.; Campbell, E. W.; Olivier, S. S. & Sweider, D. R.
Object Type:
Article
System:
The UNT Digital Library
Pulsed-Laser Deposited Amorphous Diamond and Related Materials: Synthesis, Characterization, and Field Emission Properties
Amorphous carbon films with variable sp{sup 3} content were produced by ArF (193nm) pulsed laser deposition. An in-situ ion probe was used to measure kinetic energy of C{sup +} ions. In contrast to measurements made as a function of laser fluence, ion probe measurements of kinetic energy are a convenient as well as more accurate and fundamental method for monitoring deposition conditions, with the advantage of being readily transferable for inter-laboratory comparisons. Electron energy loss spectroscopy (EELS) and spectroscopic ellipsometry measurements reveal that tetrahedral amorphous carbon (ta-C) films with the most diamond-like properties are obtained at the C ion kinetic energy of {approximately}90 eV. Film properties are uniform within a 12-15{degree} angle from the plume centerline. Tapping-mode atomic force microscope measurements show that films deposited at near-optimum kinetic energy are extremely smooth, with rms roughness of only {approximately} 1 {angstrom} over distances of several hundred nm. Field emission (FE) measurements show that ta-C does not appear to be a good electron emitter. After conditioning of ta-C films deposited on n-type Si a rather high turn-on voltage of {approximately}50 V/{micro}m was required to draw current of {approximately}1 nA to the probe. The emission was unstable and typically ceased after a few …
Date:
January 23, 1999
Creator:
Baylor, L. R.; Geohegan, D. B.; Jellison, G. E., Jr.; Lowndes, D. H.; Merkulov, V. I. & Puretzky, A. A.
Object Type:
Article
System:
The UNT Digital Library