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Sensor for measuring the atomic fraction in highly dissociated hydrogen (open access)

Sensor for measuring the atomic fraction in highly dissociated hydrogen

Atomic hydrogen is a very important constituent for processes ranging from cleaning oxide from GaAs and annealing amorphous silicon to the deposition of diamond. Because the usual techniques for measuring atomic fraction are either expensive and cumbersome to use, or unsuitable for application to highly dissociated hydrogen, a specially designed sensor was developed. Sensor design is based on a diffusion tube with noncatalytic walls, having one end open to the atom source and a catalytic closure at the other end. The sensor is simple and inexpensive to fabricate, and determining atom density is straightforward. Sensor design also inhibits thermal runaway, which occurs when atom density is high enough to impart enough recombination energy to the non-catalytic surface to substantially raise its temperature. While recombination coefficients for such surfaces are very low near room temperature, they increase nearly exponentially with temperature unless actively cooled. With the use of a straightforward calibration scheme to determine the variation in species fraction along the diffusion tube, the atomic fraction at the tube opening is determined. Design strategy, implementation considerations, and calibration method are presented. In addition, data obtained from an atomic hydrogen source are compared to relevant published data.
Date: December 31, 1994
Creator: Gardner, W.L.
Object Type: Report
System: The UNT Digital Library
Technologies for the oil and gas industry (open access)

Technologies for the oil and gas industry

This is the final report of a five-month, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The authors performed a preliminary design study to explore the plausibility of using pulse-tube refrigeration to cool instruments in a hot down-hole environment for the oil and gas industry or geothermal industry. They prepared and distributed a report showing that this appears to be a viable technology.
Date: December 31, 1998
Creator: Goff, S.J.; Swift, G.W. & Gardner, D.L.
Object Type: Report
System: The UNT Digital Library
Indium dopant/defect complexes in lightly-doped ceria (open access)

Indium dopant/defect complexes in lightly-doped ceria

Four well-defined indium-dopant/lattice-defect complexes and the non-complexed substitutional indium dopant have been observed by perturbed angular correlation (PAC) spectroscopy in cerium oxide. PAC is a nuclear hyperfine experimental method that detects interactions between a radioactive probe nucleus and nearby atoms. The magnitude and symmetry of those interactions provide a signature for the electromagnetic fields at the probe nucleus. These fields are produced by the arrangement of charges and magnetic moments in the near environment of the probe, so they provide a means of identifying defect structures.
Date: December 31, 1991
Creator: Wang, Ruiping; Gardner, J. A.; Evenson, W. E. & Sommers, J. A.
Object Type: Article
System: The UNT Digital Library
Ion exchange properties of novel hydrous metal oxide materials (open access)

Ion exchange properties of novel hydrous metal oxide materials

Hydrous metal oxide (HMO) materials are inorganic ion exchangers which have many desirable characteristics for catalyst support applications, including high cation exchange capacity, anion exchange capability, high surface area, ease of adjustment of acidity and basicity, bulk or thin film preparation, and similar chemistry for preparation of various transition metal oxides. Cation exchange capacity is engineered into these materials through the uniform incorporation of alkali cations via manipulation of alkoxide chemistry. Specific examples of the effects of Na stoichiometry and the addition of SiO{sub 2} to hydrous titanium oxide (HTO) on ion exchange behavior will be given. Acid titration and cationic metal precursor complex exchange will be used to characterize the ion exchange behavior of these novel materials.
Date: December 31, 1996
Creator: Gardner, T.J. & McLaughlin, L.I.
Object Type: Article
System: The UNT Digital Library
Comparison of the folded stripline and stacked stripline concepts to the folded waveguide launcher (open access)

Comparison of the folded stripline and stacked stripline concepts to the folded waveguide launcher

Two new concepts are being developed as possible upgrades to the folded waveguide launcher. The folded stripline is a folded waveguide with an additional conductor positioned inside. The term stripline refers to the resemblance of the design to microwave microstrip line. The conductor provides support for TEM mode propagation, which eliminates cutoff and the nonlinear frequency dependence of the waveguide impedance and phase velocity. A natural extension to the folded stripline is the stacked stripline, which comprises several stacked, independent TEM waveguides. Initial measurements indicate that both concepts have better magnetic flux coupling than the folded waveguide.
Date: December 31, 1993
Creator: Gardner, W. L.; Caughman, J. B. O.; Hoffman, D. J. & Probert, P. H.
Object Type: Article
System: The UNT Digital Library
PAC spectroscopy of electronic ceramics (open access)

PAC spectroscopy of electronic ceramics

Dilute indium dopants in cerium oxides and YBa{sub 2}Cu{sub 3}O{sub x} have been studied by{sup 111}In/Cd Perturbed Angular Correlation (PAC) spectroscopy. By controlling oxygen vacancy concentration in the cerium oxides through doping or high-temperature vacuum annealing, we have found that indium always forms a defect complex unless the sample is doped to reduce greatly the oxygen vacancy concentration. Three different vacancy-associated complexes are found with concentrations that depend on doping and oxygen stoichiometry. Another defect complex occurs in samples having negligible vacancy concentration. At low temperatures, evidence is found of interaction with an electronic hole trapped by {sup 111}Cd after the radioactive decay of the {sup 111}In parent. In YBa{sub 2}Cu{sub 3}O{sub x} the indium substitutes preferentially at the Y site but has measurable probability of substitution in at least one of the two copper sites. A symmetry change near 650 {degree}C is consistent with the well-documented orthorhombic/tetragonal transition for samples in air or oxygen.
Date: December 31, 1991
Creator: Gardner, J. A.; Wang, Ruiping; Schwenker, R.; Evenson, W. E.; Rasera, R. L. & Sommers, J. A.
Object Type: Report
System: The UNT Digital Library
Harmonic analysis of the AGS Booster imperfection (open access)

Harmonic analysis of the AGS Booster imperfection

The harmonic content of magnetic field imperfections in the AGS Booster has been determined through careful measurements of the required field corrections of transverse resonances. An analysis of the required correction yielded amplitude and phase information which points to possible sources of imperfections. Dipole and quadrupole imperfections, which are proportional to the field of bending magnets (B), are mainly driven by any misalignment of the magnets. Quadrupole and sextupole imperfections, which are proportional to dB/dt, are driven by imperfections of the eddy-current correction system. The observations also suggest the presence of a remnant field.
Date: December 31, 1993
Creator: Shoji, Y. & Gardner, C.
Object Type: Article
System: The UNT Digital Library
Transient Solid Dynamics Simulations on the Sandia/Intel Teraflop Computer (open access)

Transient Solid Dynamics Simulations on the Sandia/Intel Teraflop Computer

Transient solid dynamics simulations are among the most widely used engineering calculations. Industrial applications include vehicle crashworthiness studies, metal forging, and powder compaction prior to sintering. These calculations are also critical to defense applications including safety studies and weapons simulations. The practical importance of these calculations and their computational intensiveness make them natural candidates for parallelization. This has proved to be difficult, and existing implementations fail to scale to more than a few dozen processors. In this paper we describe our parallelization of PRONTO, Sandia`s transient solid dynamics code, via a novel algorithmic approach that utilizes multiple decompositions for different key segments of the computations, including the material contact calculation. This latter calculation is notoriously difficult to perform well in parallel, because it involves dynamically changing geometry, global searches for elements in contact, and unstructured communications among the compute nodes. Our approach scales to at least 3600 compute nodes of the Sandia/Intel Teraflop computer (the largest set of nodes to which we have had access to date) on problems involving millions of finite elements. On this machine we can simulate models using more than ten- million elements in a few tenths of a second per timestep, and solve problems more …
Date: December 31, 1997
Creator: Attaway, S.; Brown, K.; Gardner, D.; Hendrickson, B. & Barragy, T.
Object Type: Article
System: The UNT Digital Library
The partial Siberian snake experiment at the Brookhaven AGS (open access)

The partial Siberian snake experiment at the Brookhaven AGS

We are building a 4.7 Tesla-meter room temperature solenoid to be installed in a 10-foot long AGS straight section. This experiment will test the idea of using a partial snake to correct all depolarizing imperfection resonances and also test the feasibility of betatron tune jump in correction intrinsic resonances in the presence of a partial snake.
Date: December 31, 1992
Creator: Huang, H.; Caussyn, D. D.; Ellison, T.; Jones, B.; Lee, S. Y.; Schwandt, P. et al.
Object Type: Article
System: The UNT Digital Library
Drilling and geohydrologic data for test hole USW UZ-1, Yucca Mountain, Nye County, Nevada (open access)

Drilling and geohydrologic data for test hole USW UZ-1, Yucca Mountain, Nye County, Nevada

This report presents data collected to determine the hydrologic characteristics of tuffaceous rocks penetrated in test hole USW UZ-1. The borehole is the first of two deep, large-diameter, unsaturated-zone test holes dry drilled using the vacuum/reverse-air-circulation method. This test hole was drilled in and near the southwestern part of the Nevada Test Site, Nye County, Nevada, in a program conducted in cooperation with the US Department of Energy. These investigations are part of the Yucca Mountain Project (formerly the Nevada Nuclear Waste Storage Investigations) to identify a potentially suitable site for the storage of high-level radioactive wastes. Data are presented for bit and casing configurations, coring methods, sample collection, drilling rate, borehole deviation, and out-of-gage borehole. Geologic data for this borehole include geophysical logs, a lithologic log of drill-bit cuttings, and strike and distribution of fractures. Hydrologic data include water-content and water-potential measurements of drill-bit cuttings, water-level measurements, and physical and chemical analyses of water. Laboratory measurements of moisture content and matric properties from the larger drill-bit cutting fragments were considered to be representative of in-situ conditions. 3 refs., 5 figs., 10 tabs.
Date: December 31, 1990
Creator: Whitfield, M.S.; Thordarson, W.; Hammermeister, D.P. & Warner, J.B.
Object Type: Report
System: The UNT Digital Library
A Compton camera for spectroscopic imaging from 100 keV to 1 MeV (open access)

A Compton camera for spectroscopic imaging from 100 keV to 1 MeV

A review of spectroscopic imaging issues, applications, and technology is presented. Compton cameras based on solid state semiconductor detectors stands out as the best system for the nondestructive assay of special nuclear materials. A camera for this application has been designed based on an efficient specific purpose Monte Carlo code developed for this project. Preliminary experiments have been performed which demonstrate the validity of the Compton camera concept and the accuracy of the code. Based on these results, a portable prototype system is in development. Proposed future work is addressed.
Date: December 31, 1998
Creator: Earnhart, J. R. D.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The oncogenic action of ionizing radiation on rat skin. Final progress report, May 1, 1990--April 30, 1992 (open access)

The oncogenic action of ionizing radiation on rat skin. Final progress report, May 1, 1990--April 30, 1992

The multistage theory of carcinogenesis specifies that cells progress to cancer through a series of discrete, irreversible genetic alterations, but data on radiation-induced cancer incidence in rat skin suggests that an intermediate repairable alteration may occur. Data are presented on cancer induction in rat skin exposed to an electron beam (LET=0.34 keV/{mu}), a neon ion beam (LET=45) or an argon ion beam (LET=125). The rats were observed for tumors at least 78 weeks with squamous and basal cell carcinomas observed. The total cancer yield was fitted by the quadratic equation, and the equation parameters were estimated by linear regression for each type of radiation. Analysis of the DNA from the electron-induced carcinomas indicated that K-ras and/or c-myc oncogenes were activated. In situ hybridization indicated that the cancers contain subpopulations of cells with differing amounts of c-myc and H-ras amplification. The results are consistent with the idea that ionizing radiation produces stable, carcinogenically relevant lesions via 2 repairable events at low LET and via a non-repairable linked event pathway at high LET; either pathway may advance the cell by 1 stage. The proliferative response of rat epidermis following exposure to ionizing radiation was quantified by injection of {sup 14}C-thymidine. The return …
Date: December 31, 1992
Creator: Burns, F. J. & Garte, S. J.
Object Type: Report
System: The UNT Digital Library
Ultra-High Intensity Proton Accelerators and their Applications (open access)

Ultra-High Intensity Proton Accelerators and their Applications

The science and technology of proton accelerators have progressed considerably in the past three decades. Three to four orders of magnitude increase in both peak intensity and average flux have made it possible to construct high intensity proton accelerators for modern applications, such as: spallation neutron sources, kaon factory, accelerator production of tritium, energy amplifier and muon collider drivers. The accelerator design focus switched over from intensity for synchrotrons, to brightness for colliders to halos for spallation sources. An overview of this tremendous progress in both accelerator science and technology is presented, with special emphasis on the new challenges of accelerator physics issues such as: H(-) injection, halo formation and reduction of losses.
Date: December 31, 1997
Creator: Weng, W. T.
Object Type: Article
System: The UNT Digital Library
Performance and measurements of the AGS and Booster beams (open access)

Performance and measurements of the AGS and Booster beams

Analyses of Hot Gas Stream Cleanup (HGSC) ashes and descriptions of filter performance were made to address the problems with filter operation that are apparently linked to the collected ash. This task is designed to generate data base of the key properties of ashes collected from operating advanced particle filters and to relate these ash properties to the operation and performance of these filters. Activities including initial formatting of the data base and entry, modification of the permeability model, and initial design of a high-temperature test device for measuring uncompacted bulk porosity of ash aggregates (indicator of relative cohesivity of the ash, filter cake porosity/permeability). Chemical analyses of hopper and filter cake ashes from Tidd showed that the consolidation degree could not be accounted for by condensation/adsorption from the flue gas; the mechanism is likely physical rearrangement of the ash particles.
Date: December 31, 1995
Creator: Weng, W. T.
Object Type: Article
System: The UNT Digital Library
The Perry Daily Journal (Perry, Okla.), Vol. 99, No. 275, Ed. 1 Thursday, December 31, 1992 (open access)

The Perry Daily Journal (Perry, Okla.), Vol. 99, No. 275, Ed. 1 Thursday, December 31, 1992

Daily newspaper from Perry, Oklahoma that includes local, state, and national news along with advertising.
Date: December 31, 1992
Creator: Watson, Milo W.
Object Type: Newspaper
System: The Gateway to Oklahoma History
Cost-effective applications of photovoltaics for electric utilities: An overview (open access)

Cost-effective applications of photovoltaics for electric utilities: An overview

Cost targets for the large-scale entry of photovoltaic (PV) systems keep moving, subject to the vagaries of global oil prices and the economic health of the world. Over the last four decades since a practical PV device was announced, costs have come down by a factor of 20 or more and this downward trend is expected to continue, albeit at a slower pace. Simultaneously, conversion efficiencies have nearly tripled. There are many applications today for which PV is cost-effective. In recognition of this, utility interest in PV is increasing and this is manifested by projects such as PVUSA and Central and South West`s renewable resource development effort. While no major technical barriers for the entry of PV systems have been uncovered, several key issues such as power quality, system reliability, ramp rates, spinning reserve requirements, and misoperation of protection schemes will have to be dealt with as the penetration of this technology increases. PV is still in the evolutionary phase and is expected to grow for several decades to come. Fueled by environmental considerations, interest in PV is showing a healthy rise both in the minds of the public and in the planning realms of the electric power community. In …
Date: December 31, 1993
Creator: Bigger, J. E.
Object Type: Article
System: The UNT Digital Library
Photovoltaics as a worldwide energy source (open access)

Photovoltaics as a worldwide energy source

Photovoltaic energy systems have historically been treated as a bulk power generation source for the future. However, utilities and other agencies involved with electrification throughout the world are beginning to find photovoltaics a least-cost option to meet specific loads both for themselves and their customers, in both off-grid and grid-connected applications. These expanding markets offer the potential of hundreds of megawatts of sales in the coming decade, but a strategy addressing both industrial growth and user acceptance is necessary to capitalize on this opportunity. 11 refs.
Date: December 31, 1991
Creator: Jones, G. J.
Object Type: Article
System: The UNT Digital Library
Analyses of containment structures with corrosion damage (open access)

Analyses of containment structures with corrosion damage

Corrosion damage to a nuclear power plant containment structure can degrade the pressure capacity of the vessel. For the low-carbon, low- strength steels used in containments, the effect of corrosion on material properties is discussed. Strain-to-failure tests, in uniaxial tension, have been performed on corroded material samples. Results were used to select strain-based failure criteria for corroded steel. Using the ABAQUS finite element analysis code, the capacity of a typical PWR Ice Condenser containment with corrosion damage has been studied. Multiple analyses were performed with the locations of the corrosion the containment, and the amount of corrosion varied in each analysis.
Date: December 31, 1996
Creator: Cherry, J.L.
Object Type: Article
System: The UNT Digital Library
Uncertainty analysis for low-level radioactive waste disposal performance assessment at Oak Ridge National Laboratory (open access)

Uncertainty analysis for low-level radioactive waste disposal performance assessment at Oak Ridge National Laboratory

A performance assessment of the operating Solid Waste Storage Area 6 (SWSA 6) facility for the disposal of low-level radioactive waste at the Oak Ridge National Laboratory has been prepared to provide the technical basis for demonstrating compliance with the performance objectives of DOE Order 5820.2A, Chapter 111.2 An analysis of the uncertainty incorporated into the assessment was performed which addressed the quantitative uncertainty in the data used by the models, the subjective uncertainty associated with the models used for assessing performance of the disposal facility and site, and the uncertainty in the models used for estimating dose and human exposure. The results of the uncertainty analysis were used to interpret results and to formulate conclusions about the performance assessment. This paper discusses the approach taken in analyzing the uncertainty in the performance assessment and the role of uncertainty in performance assessment.
Date: December 31, 1994
Creator: Lee, D. W.; Yambert, M. W. & Kocher, D. C.
Object Type: Article
System: The UNT Digital Library
A Compton scatter camera for spectral imaging of 0.5 to 3.0 MeV gamma rays (open access)

A Compton scatter camera for spectral imaging of 0.5 to 3.0 MeV gamma rays

A prototype Compton scatter camera for imaging gamma rays has been built and tested. This camera addresses unique aspects of gamma-ray imaging at nuclear industrial sites, including gamma-ray energies in the 0.5 to 3.0 MeV range and polychromatic fields. Analytic models of camera efficiency, resolution and contaminating events are developed. The response of the camera bears strong similarity to emission computed tomography devices used in nuclear medicine. A direct Fourier based algorithm is developed to reconstruct two-dimensional images of measured gamma-ray fields. Iterative ART and MLE algorithms are also investigated. The point response of the camera to gamma rays of energies from 0.5 to 2.8 MeV is measured and compared to the analytic models. The direct reconstruction algorithm is at least ten times more efficient than the iterative algorithms are also investigated. The point response of the camera to gamma rays energies from 0.5 to 2.8 MeV is measured and compared to the analytic models. The direct reconstruction algorithm is at least ten times more efficient than the iterative algorithms and produces images that are, in general, of the same quality. Measured images of several phantoms are shown. Important results include angular resolutions as low as 4.4{degrees}, reproduction of phantom …
Date: December 31, 1994
Creator: Martin, J.B.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
LLE Review, Quarterly Report: Volume 60, July-September 1994 (open access)

LLE Review, Quarterly Report: Volume 60, July-September 1994

This volume contains articles on efficient generation of second-harmonic radiation from short-pulse lasers; calculation of the stabilization cutoff wave numbers for the Rayleigh-Taylor instability; a high-frequency silicon optical modulator; the angular dependence of stimulated Brillouin scattering; and femtosecond dynamics of ladder polymers. Three of these articles--second-harmonic generation, Rayleigh-Taylor cutoff wave numbers, and angular dependence of Brillouin scattering--are directly related to the OMEGA Upgrade, currently under construction. A summary of the status of the OMEGA Upgrade laser facility and the NLUF News for FY94 are included in this volume.
Date: December 31, 1994
Creator: Knauer, J. P.
Object Type: Report
System: The UNT Digital Library
Task 23 - background report on subsurface environmental issues relating to natural gas sweetening and dehydration operations. Topical report, February 1, 1994--February 28, 1996 (open access)

Task 23 - background report on subsurface environmental issues relating to natural gas sweetening and dehydration operations. Topical report, February 1, 1994--February 28, 1996

This report describes information pertaining to environmental issues, toxicity, environmental transport, and fate of alkanolamines and glycols associated with natural gas sweetening and dehydration operations. Waste management associated with the operations is also discussed.
Date: December 31, 1998
Creator: Sorensen, J.A.
Object Type: Report
System: The UNT Digital Library
An enhanced geometry-independent mesh weight window generator for MCNP (open access)

An enhanced geometry-independent mesh weight window generator for MCNP

A new, enhanced, weight window generator suite has been developed for MCNP{trademark}. The new generator correctly estimates importances in either an user-specified, geometry-independent orthogonal grid or in MCNP geometric cells. The geometry-independent option alleviates the need to subdivide the MCNP cell geometry for variance reduction purposes. In addition, the new suite corrects several pathologies in the existing MCNP weight window generator. To verify the correctness of the new implementation, comparisons are performed with the analytical solution for the cell importance. Using the new generator, differences between Monte Carlo generated and analytical importances are less than 0.1%. Also, assumptions implicit in the original MCNP generator are shown to be poor in problems with high scattering media. The new generator is fully compatible with MCNP`s AVATAR{trademark} automatic variance reduction method. The new generator applications, together with AVATAR, gives MCNP an enhanced suite of variance reduction methods. The flexibility and efficacy of this suite is demonstrated in a neutron porosity tool well-logging problem.
Date: December 31, 1997
Creator: Evans, T.M. & Hendricks, J.S.
Object Type: Article
System: The UNT Digital Library
Functional requirements for the Automated Transportation Management System: TTP number: RL 439002 (open access)

Functional requirements for the Automated Transportation Management System: TTP number: RL 439002

This requirements analysis, documents Department of Energy (DOE) transportation management procedures for the purpose of providing a clear and mutual understanding between users and designers of the proposed Automated Transportation Management System (ATMS). It is imperative that one understand precisely how DOE currently performs traffic management tasks; only then can an integrated system be proposed that successfully satisfies the major requirements of transportation managers and other system users. Accordingly, this report describes the current workings of DOE transportation organizations and then proposes a new system which represents a synthesis of procedures (both current and desired) which forms the basis for further systems development activities.
Date: December 31, 1992
Creator: Portsmouth, J. H.
Object Type: Report
System: The UNT Digital Library