Pressure-induced isostructural transition in PdN2 (open access)

Pressure-induced isostructural transition in PdN2

We show that a synthesized Pd-N compound crystallize into the pyrite structure by comparison of experimental and calculated Raman intensities. The decreasing Raman intensities with decreasing pressure is explained by a closing of the fundamental band gap. We further discuss the experimental decomposition of this compound at 11 GPa in terms of an isostructural transition within the pyrite structure.
Date: March 5, 2010
Creator: Aberg, D; Erhart, P; Crowhurst, J; Zaug, J M; Goncharov, A F & Sadigh, B
Object Type: Article
System: The UNT Digital Library
San Francisco State University IAC 02-06 Final Report (open access)

San Francisco State University IAC 02-06 Final Report

The Industrial Assessment Center (IAC) at San Francisco State University (SFSU) has served the cause of energy efficiency as a whole, and in particular for small and medium-sized manufacturing facilities in northern and central California, within a approximately 150 miles (radial) of San Francisco since 1992. In the current reporting period (September 1, 2002 through November 31, 2006) we have had major accomplishments, which include but are not limited to: - Performing a total of 94 energy efficiency and waste minimization audit days of 87 industrial plants - Recommending and analysis of 809 energy efficiency measures - Training 22 energy engineers, most of whom have joined energy services companies in California. - Disseminating energy efficiency information among local manufacturers - Acting as an information source for energy efficiency for local manufacturers and utilizes - Cooperating with local utilities and California Energy Commission in their energy efficiency projects - Performing various assignments by DOE such as dissemination of information on SEN initiative, conducting workshops on energy efficiency issues, contacting large energy user plants - Establishing a course on “Energy: Resources, Alternatives and Conservation” as a general education course at SFSU - Bringing energy issues to the attention of students in classrooms
Date: March 5, 2007
Creator: Ahmad R. Ganji, Ph.D., P.E., IAC DIrector
Object Type: Report
System: The UNT Digital Library
Environmental monitoring report for Pantex Plant covering 1975 (open access)

Environmental monitoring report for Pantex Plant covering 1975

During 1975 Pantex Plant conducted a monitoring program to determine the concentration of specific radioactive and non-radioactive species in the local environment. Although the plant activities involve the handling of significant quantities of uranium, plutonium and tritium, only small releases of uranium (depleted in the isotope /sup 235/U) and tritium occurred which could have affected the local environment. Monitoring data indicate that concentrations of these nuclides in the environment are below established criteria for air and water and therefore should not present a health hazard either to employees or to the public.
Date: March 5, 1976
Creator: Alexander, R.E.
Object Type: Report
System: The UNT Digital Library
Survey of high voltage electron microscopy worldwide in 1998. (open access)

Survey of high voltage electron microscopy worldwide in 1998.

High voltage TEMs were introduced commercially thirty years ago, with the installations of 500 kV Hitachi instruments at the Universities of Nagoya and Tokyo. Since that time 53 commercial instruments, having maximum accelerating potentials of 0.5-3.5 MV, will have been delivered by the end of 1998. Table 1 summarizes the sites and some information regarding those HVEMS which are available in 1998. This corrects, updates and expands an earlier report of this sort [2]. There have been three commercial HVEM manufacturers: AEI (UK), Hitachi and JEOL (Japan). The proportion of the total number of HVEMS produced by each manufacturer is similar to that reflected in Table 1: AEI and Kratos/AEI (12), Hitachi (20) and JEOL (21). The term Kratos/AEI refers to instruments delivered after the takeover of AEI by Grates in the late 1970's. In Table 1 only maximum accelerating potentials are listed, which is generally also the design value for which the resolution for imaging was optimized. It is important to realize that in many applications, especially those studying irradiation effects, much lower voltages may be employed somewhat routinely to minimize atom displacements by the incident electron beam during analysis. These minimum values range from 100 kV for the …
Date: March 5, 1998
Creator: Allen, C. W.
Object Type: Article
System: The UNT Digital Library
Diagnostic system for measurement of particle balance in TMX-U (open access)

Diagnostic system for measurement of particle balance in TMX-U

Several diagnostics measure the particle sources and losses in the Tandem Mirror Experiment-Upgrade (TMX-U) plasma. An absolutely calibrated high-speed (0.5 ms per frame) filtered (6561 A) video camera measures the total ionization source as a function of radius. An axial view of the plasma automatically integrates the axial variations within the depth of field of the system. Another camera, viewing the plasma radially, measures the axial source variations near the deuterium fueling source. Axial ion losses are measured by an array of Faraday cups that are equipped with grids for repelling electrons and are mounted at each end of the experiment. Unequal ion and electron (nonambipolar) radial losses are inferred from net current measurements on an array of grounded plates at each end. Any differences between the measured particle losses and sources may be attributed to ambipolar radial losses and/or azimuthal asymmetries in the particle-loss profiles. Methods of system calibration, along with details of computer data acquisition and processing of this relatively large set of data, are also presented. 6 refs., 1 fig.
Date: March 5, 1986
Creator: Allen, S. L.; Correll, D. L.; Hill, D. N.; Wood, R. D. & Brown, M. D.
Object Type: Article
System: The UNT Digital Library
The correlation between swelling and radiation-induced segregation in iron-chromium-nickel alloys. (open access)

The correlation between swelling and radiation-induced segregation in iron-chromium-nickel alloys.

The magnitudes of both void swelling and radiation-induced segregation (RIS) in iron-chromium-nickel alloys are dependent on bulk alloy composition. Because the diffusivity of nickel via the vacancy flux is slow relative to chromium, nickel enriches and chromium depletes at void surfaces during irradiation. This local composition change reduces the subsequent vacancy flux to the void, thereby reducing void swelling. In this work, the resistance to swelling from major element segregation is estimated using diffusivities derived from grain boundary segregation measurements in irradiated iron-chromium-nickel alloys. The resistance to void swelling in iron- and nickel-base alloys correlates with the segregation and both are functions of bulk alloy composition. Alloys that display the greatest amount of nickel enrichment and chromium depletion are found to be most resistant to void swelling, as predicted. Additionally, swelling is shown to be greater in alloys in which the RIS profiles are slow to develop.
Date: March 5, 1998
Creator: Allen, T. R.; Busby, J. T.; Kenik, E. A. & Was, G. S.
Object Type: Article
System: The UNT Digital Library
Modeling the effect of irradiation and post-irradiation annealing on grain boundary composition in austenitic Fe-Cr-Ni alloys. (open access)

Modeling the effect of irradiation and post-irradiation annealing on grain boundary composition in austenitic Fe-Cr-Ni alloys.

Many irradiation effects in Fe-Cr-Ni alloys such as radiation-induced segregation, radiation-enhanced diffusion, and void swelling are known to vary with bulk alloy composition. The development of microstructural and microchemical changes during irradiation and during post-irradiation annealing is determined by the rate of diffusion of point defects and alloying elements. To accurately predict the changes in grain boundary chemistry due to radiation-induced segregation and post-irradiation annealing, the composition dependence of diffusion parameters, such as the migration energy, must be known. A model has been developed which calculates migration diffusivity. The advantages of this calculational method are that a single set of input parameters can be used for a wide range of bulk alloy compositions, and the effects of local order can easily be incorporated into the calculations. A description of the model is presented, and model calculations are compared to segregation measurements from seven different iron-chromium-nickel alloys, irradiated with protons to doses from 0.1 to 3.0 dpa at temperatures between 200 C and 600 C. Results show that segregation trends can be modeled using a single set of input parameters with the difference between model calculation and measurement being less than 5 at%, but usually less than 2 at%. Additionally, model …
Date: March 5, 1998
Creator: Allen, T.; Busby, J. T.; Kenik, E. A. & Was, G. S.
Object Type: Article
System: The UNT Digital Library
Allinea DDT as a Parallel Debugging Alternative to Totalview (open access)

Allinea DDT as a Parallel Debugging Alternative to Totalview

Totalview, from the Etnus Corporation, is a sophisticated and feature rich software debugger for parallel applications. As Totalview has gained in popularity and market share its pricing model has increased to the point where it is often prohibitively expensive for massively parallel supercomputers. Additionally, many of Totalview's advanced features are not used by members of the scientific computing community. For these reasons, supercomputing centers have begun to search for a basic parallel debugging tool which can be used as an alternative to Totalview. As the cost and complexity of Totalview has increased over the years, scientific computing centers have started searching for a viable parallel debugging alternative. DDT (Distributed Debugging Tool) from Allinea Software is a relatively new parallel debugging tool which aims to provide much of the same functionality as Totalview. This review outlines the basic features and limitations of DDT to determine if it can be a reasonable substitute for Totalview. DDT was tested on the NERSC platforms Bassi, Seaborg, Jacquard and Davinci with Fortran90, C, and C++ codes using MPI and OpenMP for parallelism.
Date: March 5, 2007
Creator: Antypas, K.B.
Object Type: Report
System: The UNT Digital Library
Hydrodynamic instability in strong media (open access)

Hydrodynamic instability in strong media

This paper reviews the All Russian Scientific Research Institute of Experimental Physics open publications on hydrodynamic instability in strong media.
Date: March 5, 1997
Creator: Bakhrakh, S.M.; Drennov, O.B. & Kovalev, N.P.
Object Type: Report
System: The UNT Digital Library
Advances in processing of Ag-sheathed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconductors. (open access)

Advances in processing of Ag-sheathed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconductors.

Advances in the processing and fabrication of Ag-sheathed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Bi-2223) high-T{sub c} superconductors by the powder-in-tube technique continue to bring this material closer to commercial applications. Enhancement of the transport critical current density (J{sub c}) of Ag-sheathed Bi-2223 tapes was achieved by increasing the packing density of the precursor powder, improving mechanical deformation, and adjusting the cooling rate. Long lengths (>150 m) of multifilamentary Bi-2223 tapes have been fabricated and carry critical currents (I{sub c}) of >50 A (J{sub c} {approx} 25 kA/cm{sup 2}) at 77 K in self-field. A 1260-m-long tape carried an I{sub c} of 18 A (J{sub c} {approx} 12 kA/cm{sup 2}) from end-to-end. Several prototype coils have been assembled from these long-length tapes. Recent progress in the fabrication of Bi-2223 tapes is presented in this paper.
Date: March 5, 1998
Creator: Balachandran, U.; Eror, N. G.; Haldar, P. & Lelovic, M.
Object Type: Article
System: The UNT Digital Library
Status of irradiations performed by testing and irradiation services for BNW as of February 18, 1968 (open access)

Status of irradiations performed by testing and irradiation services for BNW as of February 18, 1968

This report itemizes the irradiations performed by Testing and Irradiation Services for Battelle-Northwest. It lists the material being irradiated, awaiting disposition and material shipped during the report period. Data are given table form. An explanation of the various columns in the report is given.
Date: March 5, 1968
Creator: Barker, L. V.
Object Type: Report
System: The UNT Digital Library
NANOSTRUCTURED METAL OXIDE CATALYSTS VIA BUILDING BLOCK SYNTHESES (open access)

NANOSTRUCTURED METAL OXIDE CATALYSTS VIA BUILDING BLOCK SYNTHESES

A broadly applicable methodology has been developed to prepare new single site catalysts on silica supports. This methodology requires of three critical components: a rigid building block that will be the main structural and compositional component of the support matrix; a family of linking reagents that will be used to insert active metals into the matrix as well as cross link building blocks into a three dimensional matrix; and a clean coupling reaction that will connect building blocks and linking agents together in a controlled fashion. The final piece of conceptual strategy at the center of this methodology involves dosing the building block with known amounts of linking agents so that the targeted connectivity of a linking center to surrounding building blocks is obtained. Achieving targeted connectivities around catalytically active metals in these building block matrices is a critical element of the strategy by which single site catalysts are obtained. This methodology has been demonstrated with a model system involving only silicon and then with two metal-containing systems (titanium and vanadium). The effect that connectivity has on the reactivity of atomically dispersed titanium sites in silica building block matrices has been investigated in the selective oxidation of phenols to benezoquinones. …
Date: March 5, 2013
Creator: Barnes, Craig E.
Object Type: Report
System: The UNT Digital Library
Novel Low-Cost Process for the Gasification of Biomass and Low-Rank Coals (open access)

Novel Low-Cost Process for the Gasification of Biomass and Low-Rank Coals

Farm Energy envisaged a phased demonstration program, in which a pilot-scale straw gasifier will be installed on a farm. The synthesis gas product will be used to initially (i) generate electricity in a 300 kW diesel generator, and subsequently (ii) used as a feedstock to produce ethanol or mixed alcohols. They were seeking straw gasification and alcohol synthesis technologies that may be implemented on farm-scale. The consortium, along with the USDA ARS station in Corvallis, OR, expressed interest in the dual-bed gasification concept promoted by WRI and Taylor Energy, LLC. This process operated at atmospheric pressure and employed a solids-circulation type oxidation/reduction cycle significantly different from traditional fluidized-bed or up-draft type gasification reactors. The objectives of this project were to perform bench-scale testing to determine technical feasibility of gasifier concept, to characterize the syngas product, and to determine the optimal operating conditions and configuration. We used the bench-scale test data to complete a preliminary design and cost estimate for a 1-2 ton per hour pilot-scale unit that is also appropriate for on-farm scale applications. The gasifier configuration with the 0.375-inch stainless steel balls recirculating media worked consistently and for periods up to six hours of grass feed. The other principle …
Date: March 5, 2009
Creator: Barton, Thomas
Object Type: Report
System: The UNT Digital Library
Actinic Mask Inspection at the ALS Initial Design Review (open access)

Actinic Mask Inspection at the ALS Initial Design Review

This report is the first milestone report for the actinic mask blank inspection project conducted at the VNL, which forms sub-section 3 of the Q1 2003 mask blank technology transfer program at the VNL. Specifically this report addresses deliverable 3.1.1--design review and preliminary tool design. The goal of this project is to design an actinic mask inspection tool capable of operating in two modes: high-speed scanning for the detection of multilayer defects (inspection mode), and a high-resolution aerial image mode in which the image emulates the imaging illumination conditions of a stepper system (aerial image or AIM mode). The purpose and objective of these two modes is as follows: (1) Defect inspection mode--This imaging mode is designed to scan large areas of the mask for defects EUV multilayer coatings. The goal is to detect the presence of multilayer defects on a mask blank and to store the co-ordinates for subsequent review in AIM mode, thus it is not essential that the illumination and imaging conditions match that of a production stepper. Potential uses for this imaging mode include: (a) Correlating the results obtained using actinic inspection with results obtained using other non-EUV defect inspection systems to verify that the non-EUV …
Date: March 5, 2003
Creator: Barty, A.; Chapman, H.; Sweeney, D.; Levesque, R.; Bokor, J.; Gullikson, E. et al.
Object Type: Report
System: The UNT Digital Library
Searching for top, Higgs, and supersymmetry: the minimum invariant mass technique (open access)

Searching for top, Higgs, and supersymmetry: the minimum invariant mass technique

Supersymmetric particls, Higgs mesons, the top quark and other heavy objects are expected to decay frequently into three or more body final states in which at least one particle, such a neutrino or photino, is non-interacting. A method is described for obtaining an excellent estimate of both the mass and the longitudinal momentum of the parent state. The probable longitudinal momenta of the non-interacting particle and of the parent, and the minimum invariant mass of the parent are derived from a minimization procedure. The distributions in these variables are shown to peak sharply at their true values.
Date: March 5, 1984
Creator: Berger, E. L.
Object Type: Article
System: The UNT Digital Library
Research and development for the declassification productivity initiative. Quarterly report, January 1997--August 1997 (open access)

Research and development for the declassification productivity initiative. Quarterly report, January 1997--August 1997

The highlight for the first quarter was the presentation of research progress and findings at the DPI Symposium on March 5, 1997. Since that presentation, additional progress was slowed down due to the decreased budget funding for year two, and consequently, the decrease in time-effort of the principal investigators. This report summarizes the progress in each of the topical areas to date. A research article has been prepared for publication for the Optical Character Recognition project; two progress reports are included for the Logical Analysis project; and two progress reports for the Knowledge Representation project. Research activities for the Tipster Technology project will resume this fall.
Date: March 5, 1997
Creator: Bessonet, C.G. de
Object Type: Report
System: The UNT Digital Library
Status of LOCA research in high burnup cladding performance program. (open access)

Status of LOCA research in high burnup cladding performance program.

None
Date: March 5, 2002
Creator: Billone, M. C.; Strain, R. V. & Yan, Y.
Object Type: Article
System: The UNT Digital Library
Analysis of Geomechanical Behavior for the Drift Scale Test (open access)

Analysis of Geomechanical Behavior for the Drift Scale Test

The Drift Scale Test (DST) now underway at Yucca Mountain has been simulated using a Drift Scale Distinct Element (DSDE) model. Simulated deformations show good agreement with field deformation measurements. Results indicate most fracture deformation is located above the crown of the Heated Drift. This work is part of the model validation effort for the DSDE model, which is used to assess thermal-mechanical effects on the hydrology of the rock mass surrounding a potential repository.
Date: March 5, 2001
Creator: Blair, S. C.; Carlson, S. R. & Wagoner, J. L.
Object Type: Article
System: The UNT Digital Library
Analysis of Geomechanical Behavior for the Drift Scale Test (open access)

Analysis of Geomechanical Behavior for the Drift Scale Test

The Drift Scale Test (DST) now underway at Yucca Mountain has been simulated using a Drift Scale Distinct Element (DSDE) model. Simulated deformations show good agreement with field deformation measurements. Results indicate most fracture deformation is located above the crown of the Heated Drift. This work is part of the model validation effort for the DSDE model, which is used to assess thermal-mechanical effects on the hydrology of the rock mass surrounding a potential repository.
Date: March 5, 2001
Creator: Blair, S.C.; Carlson, S.R. & Wagoner, J.L.
Object Type: Article
System: The UNT Digital Library
Final report for Process Test MR-105-4 -- Radiation effects of the removal of front cap supported shielding slugs (open access)

Final report for Process Test MR-105-4 -- Radiation effects of the removal of front cap supported shielding slugs

Corrosion of aluminum front cap supported shielding slugs has been noted at all reactors except C Reactor which has galvanized shielding pieces. There has been a considerable amount of difficulty caused by sticking of the places. The difficulty is caused by the growth of corrosion products in the annulus around the shielding piece which affectively siezes it. As recently as June, 1953 the shielding pieces on nearly 50 per cent of a group of 40 tubes at B Reactor were corroded to the extent that a pipe wrench was required for their removal. Similar instances, to varying degrees, have occurred at all reactors except C.The purpose of this test was to evaluate the radiation affects of removing the front shielding pieces as part of a program to eliminate the sticking problem.
Date: March 5, 1954
Creator: Bloomstrand, R. R.
Object Type: Report
System: The UNT Digital Library
History of geophysical studies at the Waste Isolation Pilot Plant (WIPP), southeastern New Mexico (open access)

History of geophysical studies at the Waste Isolation Pilot Plant (WIPP), southeastern New Mexico

A variety of geophysical methods including the spectrum of seismic, electrical, electromagnetic and potential field techniques have supported characterization, monitoring and experimental studies at the Waste Isolation Pilot Plant (WIPP). The geophysical studies have provided significant understanding of the nature of site deformation, tectonics and stability. Geophysical methods have delineated possible brine reservoirs beneath the underground facility and have defined the disturbed rock zone that forms around underground excavations. The role of geophysics in the WIPP project has evolved with the project. The early uses were for site characterization to satisfy site selection criteria or factors. As the regulatory framework for WIPP grew since 1980, the geophysics program supported experimental and field programs such as Salado hydrogeology and underground room systems and excavations. In summary, the major types of issues that geophysical studies addressed for WIPP are: Site Characterization; Castile Brine Reservoirs; Rustler/Dewey Lake Hydrogeology; Salado Hydrogeology; and Excavation Effects. The nature of geophysics programs for WIPP has been to support investigation rather than being the principal investigation itself. The geophysics program has been used to define conceptual models (e.g., the Disturbed Rock Zone-DRZ) or to test conceptual models (e.g., high transmissivity zones in the Rustler Formation). The geophysics program …
Date: March 5, 1997
Creator: Borns, D. J.
Object Type: Article
System: The UNT Digital Library
Holographic and acoustic emission evaluation of pressure vessels (open access)

Holographic and acoustic emission evaluation of pressure vessels

Optical holographic interfereometry and acoustic emission monitoring were simultaneously used to evaluate two small, high pressure vessels during pressurization. The techniques provide pressure vessel designers with both quantitative information such as displacement/strain measurements and qualitative information such as flaw detection. The data from the holographic interferograms were analyzed for strain profiles. The acoustic emission signals were monitored for crack growth and vessel quality.
Date: March 5, 1980
Creator: Boyd, D.M.
Object Type: Article
System: The UNT Digital Library
Transient Model for Keyhole During Laser Welding (open access)

Transient Model for Keyhole During Laser Welding

A novel approach to simulating the dominant dynamic processes present during concentrated energy beam welding of metals is presented. A model for transient behavior of the front keyhole wall is developed. It is assumed that keyhole propagation is dominated by evaporation recoil-driven melt expulsion from the beam interaction zone. Results from the model show keyhole instabilities consistent with experimental observations of metal welding, metal cutting and ice welding.
Date: March 5, 1999
Creator: Bragg, William David; Damkroger, Brian; Kempka, Steven & Semak, Vladimir V.
Object Type: Article
System: The UNT Digital Library
Development of aerogel-lined targets for inertial confinement fusion experiments (open access)

Development of aerogel-lined targets for inertial confinement fusion experiments

None
Date: March 5, 2013
Creator: Braun, Tom
Object Type: Thesis or Dissertation
System: The UNT Digital Library