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Waste processing air cleaning (open access)

Waste processing air cleaning

Waste processing and preparing waste to support waste processing relies heavily on ventilation. Ventilation is used at the Hanford Site on the waste storage tanks to provide confinement, cooling, and removal of flammable gases.
Date: July 27, 1998
Creator: Kriskovich, J. R.
System: The UNT Digital Library
ATI TDA 5A aerosol generator evaluation (open access)

ATI TDA 5A aerosol generator evaluation

Oil based aerosol ``Smoke`` commonly used for testing the efficiency and penetration of High Efficiency Particulate Air filters (HEPA) and HEPA systems can produce flammability hazards that may not have been previously considered. A combustion incident involving an aerosol generator has caused an investigation into the hazards of the aerosol used to test HEPA systems at Hanford.
Date: July 27, 1998
Creator: Gilles, D. A.
System: The UNT Digital Library
Fatigue crack initiation in carbon and low-alloy steels in light water reactor environments : mechanism and prediction. (open access)

Fatigue crack initiation in carbon and low-alloy steels in light water reactor environments : mechanism and prediction.

Section 111 of the ASME Boiler and Pressure Vessel Code specifies fatigue design curves for structural materials. The effects of reactor coolant environments are not explicitly addressed by the Code design curves. Recent test data illustrate potentially significant effects of light water reactor (LWR) coolant environments on the fatigue resistance of carbon and low-alloy steels. Under certain loading and environmental conditions, fatigue lives of test specimens may be shorter than those in air by a factor of {approx}70. The crack initiation and crack growth characteristics of carbon and low-alloy steels in LWR environments are presented. Decreases in fatigue life of these steels in high-dissolved-oxygen water are caused primarily by the effect of environment on growth of short cracks < 100 {micro}m in depth. The material and loading parameters that influence fatigue life in LWR environments are defined. Fatigue life is decreased significantly when five conditions are satisfied simultaneously, viz., applied strain range, service temperature, dissolved oxygen in water, and S content in steel are above a threshold level, and loading strain rate is below a threshold value. Statistical models have been developed for estimating the fatigue life of these steels in LWR environments. The significance of the effect of environment …
Date: January 27, 1998
Creator: Chopra, O. K. & Shack, W. J.
System: The UNT Digital Library
The dimensional stability of lightly-loaded epoxy joints (open access)

The dimensional stability of lightly-loaded epoxy joints

The use of adhesives to bond metal mounting structures to optical components can significantly simplify the design of an optical system. In precision applications, dimensional instability of the adhesive must be included as a component of the overall error budget. This paper describes the qualification testing of a balanced heterodyne interferometer system in a carefully controlled environment for the purpose of measuring joint stability. Results of this qualification test are reported.
Date: August 27, 1998
Creator: Badami, V G; Lawton, K M; Patterson, S R & Tajbakhsh, H
System: The UNT Digital Library
Three-degree-of-freedom optic mount for extreme ultraviolet lithography (open access)

Three-degree-of-freedom optic mount for extreme ultraviolet lithography

A mechanism to finely align optics for extreme ultraviolet lithography applications is presented. The mechanism is a small motion parallel link manipulator with flexure joints that exhibits nanometer level positioning capability. Performance results of a prototype system are given in this paper.
Date: August 27, 1998
Creator: Hale, L.; Jensen, S.; Malsbury, T.; Parker, J. & Tajbakhsh, H.
System: The UNT Digital Library
Development of a Radiative-Hydrodynamics Testbed Using the Petawatt Laser Facility (open access)

Development of a Radiative-Hydrodynamics Testbed Using the Petawatt Laser Facility

Many of the conditions believed to underlie astrophysical phenomena have been difficult to achieve in a laboratory setting. For example, models of supernova remnant evolution rely on a detailed understanding of the propagation of shock waves with gigabar pressures at temperatures of 1 keV or more where radiative effects can be important. Current models of gamma ray bursts posit a relativistically expanding plasma fireball with copious production of electron-positron pairs, a difficult scenario to experimentally verify. However, a new class of lasers, such as the Petawatt laser,Perry 1996 are capable of producing focused intensities greater than 10<sup>20</sup> W/cm&sup2; where such relativistic effects can be observed and even dominate the laser-target interaction. There is ample evidence in observational data from supernova remnants of the aftermath of the passage of radiative shock or blast waves. In the early phases of supernova remnant evolution, the radially-expanding shock wave expands nearly adiabatically since it is traveling at a very high velocity as it begins to sweep up the surrounding interstellar gas. A Sedov-Taylor blast wave solution can be applied to this phase,Taylor 1950, Sedov 1959 when the mass of interstellar gas swept up by the blast greatly exceeds the mass of the stellar ejecta, …
Date: August 27, 1998
Creator: Koch, J. A.; Bell, P. M.; Brown, C.; Budil, K. S.; Estabrook, K. G.; Gold, D. M. et al.
System: The UNT Digital Library
Giving effective poster presentations (open access)

Giving effective poster presentations

Giving an effective poster presentation can be easy and rewarding with attention to a few proven concepts. Define your audience. Keep the words and graphics clear, concise, and eye-catching. Remember, you have three seconds to attract attention and 30 seconds to get your message across.
Date: August 27, 1998
Creator: Rice, J A
System: The UNT Digital Library
Disposition of Nuclear Waste Using Subcritical Accelerator-Driven Systems (open access)

Disposition of Nuclear Waste Using Subcritical Accelerator-Driven Systems

ATW destroys virtually all the plutonium and higher actinides without reprocessing the spent fuel in a way that could lead to weapons material diversion. An ATW facility consists of three major elements: (1) a high-power proton linear accelerator; (2) a pyrochemical spent fuel treatment i waste cleanup system; (3) a liquid lead-bismuth cooled burner that produces and utilizes an intense source-driven neutron flux for transmutation in a heterogeneous (solid fuel) core. The concept is the result of many years of development at LANL as well as other major international research centers. Once demonstrated and developed, ATW could be an essential part of a global non-proliferation strategy for countries that could build up large quantities of plutonium from their commercial reactor waste. ATW technology, initially proposed in the US, has received wide and rapidly increasing attention abroad, especially in Europe and the Far East with major programs now being planned, organized and tided. Substantial convergence presently exists on the technology choices among the programs, opening the possibility of a strong and effective international collaboration on the phased development of the ATW technology.
Date: June 27, 1998
Creator: Doolen, G. D.; Venneri, F.; Li, N.; Williamson, M. A.; Houts, M. & Lawrence, G.
System: The UNT Digital Library
Disposition options for {sup 233}U (open access)

Disposition options for {sup 233}U

The United States is implementing a program to dispose of excess nuclear-weapons-usable materials--including {sup 233}U. A series of studies have identified multiple {sup 233}U disposition options, and these options are described herein. Most of the options involve adding depleted uranium containing {sup 238}U to the {sup 233}U. Converting the {sup 233}U into a mixture of <12 wt % {sup 233}U in {sup 238}U converts the weapons-usable {sup 233}U into nonweapons-usable {sup 233}U. For {sup 233}U that is considered waste, further isotopic dilution to <0.66 wt % {sup 233}U in {sup 238}U minimizes potential long-term repository criticality concerns and in many cases minimizes final waste volumes.
Date: April 27, 1998
Creator: Forsberg, C.W.; Icenhour, A.S. & Krichinsky, A.M.
System: The UNT Digital Library
POLARIZED NEUTRONS IN RHIC (open access)

POLARIZED NEUTRONS IN RHIC

There does not appear to be any obvious way to accelerate neutrons, polarized or otherwise, to high energies by themselves. To investigate the behavior of polarized neutrons the authors therefore have to obtain them by accelerating them as components of heavier nuclei, and then sorting out the contribution of the neutrons in the analysis of the reactions produced by the heavy ion beams. The best neutron carriers for this purpose are probably {sup 3}He nuclei and deuterons. A polarized deuteron is primarily a combination of a proton and a neutron with their spins pointing in the same direction; in the {sup 3}He nucleus the spins of the two protons are opposite and the net spin (and magnetic moment) is almost the same as that of a free neutron. Polarized ions other than protons may be accelerated, stored and collided in a ring such as RHIC provided the techniques proposed for polarized proton operation can be adapted (or replaced by other strategies) for these ions. To accelerate polarized particles in a ring, one must make provisions for overcoming the depolarizing resonances that occur at certain energies. These resonances arise when the spin tune (ratio of spin precession frequency to orbit frequency) …
Date: April 27, 1998
Creator: Courant, E. D.
System: The UNT Digital Library
Analysis of soil-structure interaction due to ambient vibration (open access)

Analysis of soil-structure interaction due to ambient vibration

This paper presents the results of a study to evaluate the effects of soil-structure interaction (SSI) on the ambient vibration response of the switchyard/target area (S/TA) buildings at the National Ignition Facility (NIF) presently under construction at the Lawrence Livermore National Laboratory (LLNL) in Livermore, California. This laser facility houses optical and other special equipment whose alignment stability is sensitive to vibrations caused by ambient vibrations or other vibrating sources. In evaluating the deformations and displacements of the S/TA structures, the contribution of the SSI to the overall system flexibility can be very significant. The present study examines the results of fixed-base and SSI analyses of these massive stiff structures to develop an understanding of the potential contribution of SSI to the overall system displacements and deformations. A simple procedure using a set of factors is recommended for scaling the results of fixed-base analyses to approximately account for SSI effects.
Date: March 27, 1998
Creator: Tabatabaie, M., Sommer, S.C.
System: The UNT Digital Library
Analysis of Cu Diffusion in ZnTe-Based Contacts for Thin-Film CdS/CdTe Solar Cells (open access)

Analysis of Cu Diffusion in ZnTe-Based Contacts for Thin-Film CdS/CdTe Solar Cells

Ohmic contacts to thin-film CdS/CdTe photovoltaic devices have been formed using a two-layer contact interface of undoped ZnTe (ZnTe) and Cu-doped ZnTe (ZnTe:Cu), followed by Ni or Ti as an outer metallization. Secondary ion mass spectroscopy (SIMS) is used to study Cu diffusion within this back-contact structure, and also, to monitor Cu diffusion from the contact into the CdTe. When Ni metallization is used, the ZnTe:Cu layer becomes increasingly depleted of Cu, and Ni diffusion into the ZnTe:Cu increases as the contact deposition temperature increases from 100 C to 300 C. Cu depletion is not observed when Ni is replaced with Ti. Diffusion of Cu from the ZnTe:Cu layer into the ZnTe layer also increases with contact deposition temperature, and produces a buildup of Cu at the ZnTe/CdTe interface. High-mass resolution SIMS indicates that, although Cu levels in the CdTe remain low, Cu diffusion from the contact proceeds into the CdTe layer and toward the CdTe/CdS junction region.
Date: October 27, 1998
Creator: Narayanswamy, C. (Department of Physics & Astronomy, University of Toledo) & Gessert, T. A. and Asher, S. E. (National Renewable Energy Laboratory)
System: The UNT Digital Library
Scaling behavior in interference lithography (open access)

Scaling behavior in interference lithography

Interference lithography is an emerging, technology that provides a means for achieving high resolution over large exposure areas (approximately 1 m{sup 2}) with virtually unlimited depth of field. One- and two-dimensional arrays of deep submicron structures can be created using near i-line wavelengths and standard resist processing. In this paper, we report on recent advances in the development of this technology, focusing, in particular, on how exposure latitude and resist profile scale with interference period We present structure width vs dose curves for periods ranging from 200 nm to 1 um, demonstrating that deep submicron structures can be generated with exposure latitudes exceeding 30%. Our experimental results are compared to simulations based on PROLITIV2.
Date: February 27, 1998
Creator: Agayan, R.R.; Banyai, W.C. & Fernandez, A.
System: The UNT Digital Library
INDUCED BIOCHEMICAL INTERACTIONS IN IMMATURE AND BIODEGRADED HEAVY CRUDE OILS (open access)

INDUCED BIOCHEMICAL INTERACTIONS IN IMMATURE AND BIODEGRADED HEAVY CRUDE OILS

Studies in which selective chemical markers have been used to explore the mechanisms by which biocatalysts interact with heavy crude oils have shown that the biochemical reactions follow distinct trends. The term biocatalyst refers to a group of extremophilic microorganisms which, under the experimental conditions used, interact with heavy crude oils to (1) cause a redistribution of hydrocarbons, (2) cause chemical changes in oil fractions containing sulfur compounds and lower the sulfur content, (3) decrease organic nitrogen content, and (4) decrease the concentration of trace metals. Current data indicate that the overall effect is due to simultaneous reactions yielding products with relatively higher concentration of saturates and lower concentrations of aromatics and resins. The compositional changes depend on the microbial species and the chemistry of the crudes. Economic analysis of a potential technology based on the available data indicate that such a technology, used in a pre-refinery mode, may be cost efficient and promising. In the present paper, the background of oil biocatalysis and some recent results will be discussed.
Date: October 27, 1998
Creator: Premusic, E. T.; Lin, M. S.; Bohenek, M.; Joshi-Topé, G.; Shelenkova, L. & Zhou, W. M.
System: The UNT Digital Library
In situ hydrothermal oxidative destruction of DNAPLS in a creosote contaminated site (open access)

In situ hydrothermal oxidative destruction of DNAPLS in a creosote contaminated site

Hydrous Pyrolysis / Oxidation (HPO) is an in situ thermal remediation technology that uses hot, oxygenated groundwater to completely mineralize a wide range of organic pollutants. A field demonstration of HPO was performed at a creosote contaminated site during the summer of 1997. The groundwater was heated by steam injections and oxygen was added by coinjection of compressed air. The remediation was monitored from multiple groundwater monitoring wells. Dissolved organic carbon levels increased in response to steam injections as a result of the enhanced dissolution and mobilization of the creosote into the heated groundwater. Elevated concentrations of partially oxidized organic compounds (i.e. phenols, benzoic acid, fluorenone, anthrone and 9,10- anthracenedione), decreased levels of dissolved oxygen and isotopic shifts in the dissolved inorganic pool were indicators of partial to complete oxidative destruction of the creosote in the heated aquifer as a result of the HPO process.
Date: February 27, 1998
Creator: Leif, R. N., LLNL
System: The UNT Digital Library
Spatial frequency domain error budget (open access)

Spatial frequency domain error budget

The aim of this paper is to describe a methodology for designing and characterizing machines used to manufacture or inspect parts with spatial-frequency-based specifications. At Lawrence Livermore National Laboratory, one of our responsibilities is to design or select the appropriate machine tools to produce advanced optical and weapons systems. Recently, many of the component tolerances for these systems have been specified in terms of the spatial frequency content of residual errors on the surface. We typically use an error budget as a sensitivity analysis tool to ensure that the parts manufactured by a machine will meet the specified component tolerances. Error budgets provide the formalism whereby we account for all sources of uncertainty in a process, and sum them to arrive at a net prediction of how "precisely" a manufactured component can meet a target specification. Using the error budget, we are able to minimize risk during initial stages by ensuring that the machine will produce components that meet specifications before the machine is actually built or purchased. However, the current error budgeting procedure provides no formal mechanism for designing machines that can produce parts with spatial-frequency-based specifications. The output from the current error budgeting procedure is a single number …
Date: August 27, 1998
Creator: Hauschildt, H & Krulewich, D
System: The UNT Digital Library
Salvaging pyrotechnic data with minor overloads and offsets (open access)

Salvaging pyrotechnic data with minor overloads and offsets

The authors are sometimes presented with data with serious flaws, like saturation, over-range, zero shifts, and impulsive noise, including much of the available pyrotechnic data. Obviously, these data should not be used if at all possible. However, they are sometimes forced to use these data as the only data available. A method to salvage these data using wavelets is discussed. The results must be accepted with the understanding that the answers are credible, not necessarily correct. None of the methods will recover information lost due to saturation and over-range with the subsequent nonlinear behavior of the data acquisition system. The results are illustrated using analytical examples and flawed pyrotechnic data.
Date: January 27, 1998
Creator: Smallwood, D.O. & Cap, J.S.
System: The UNT Digital Library
Synthesis, scale-up, and characterization of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) (open access)

Synthesis, scale-up, and characterization of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105)

We have synthesized 4OOg of the new, insensitive, energetic heterocycle, 2,6-diamino-3,5-dinitropyrazine-l-oxide (LLM-105) with 81% the energy of HMX and excellent thermal stability. The synthesis is a three step reaction sequence from the commercially available starting material, 2,6-dichloropyrazine, with an overall yield of 36%. In this paper we will describe the scale-up of the synthesis of LLM- 105 and report on performance and shock sensitivity experiments performed on this material.
Date: April 27, 1998
Creator: Pagoria, P. F.
System: The UNT Digital Library
A diffusion model for picosecond electron bunches from negative electron affinity GaAs photo cathodes (open access)

A diffusion model for picosecond electron bunches from negative electron affinity GaAs photo cathodes

Even though theoretical estimates predict response times for the photo emission process of electrons from a negative electron affinity GaAs photo emitter in excess of hundreds of picoseconds, recent measurements found electron bunch durations of 40 ps or less. This work presents precise measurements of picosecond electron bunches from a negative affinity bulk GaAs photo cathode and develops a model which explains the measured bunch durations as well as the observed bunch shapes. The bunch shape turns out to be independent from the quantum efficiency of the photo emitter.
Date: October 27, 1998
Creator: Hartmann, P.; Bermuth, J.; Harrach, D. v.; Hoffmann, J.; Kobis, S.; Reichert, E. et al.
System: The UNT Digital Library
Operation of the Bayes Inference Engine (open access)

Operation of the Bayes Inference Engine

The authors have developed a computer application, called the Bayes Inference Engine, to enable one to make inferences about models of a physical object from radiographs taken of it. In the BIE calculational models are represented by a data-flow diagram that can be manipulated by the analyst in a graphical-programming environment. The authors demonstrate the operation of the BIE in terms of examples of two-dimensional tomographic reconstruction including uncertainty estimation.
Date: July 27, 1998
Creator: Hanson, K. M. & Cunningham, G. S.
System: The UNT Digital Library
Fracture toughness testing and toughening mechanisms of some commercial cobalt-free hardfacing alloys (open access)

Fracture toughness testing and toughening mechanisms of some commercial cobalt-free hardfacing alloys

Hardfacing alloys are weld deposited to provide a wear resistant surface for structural base materials. Commercial low cobalt hardfacing alloys are being evaluated to reduce plant activation levels. Since hardfacing alloys typically must be resistant to cracking to assure adequate in service performance, fracture toughness is a critical material property. Fracture toughness (K{sub IC}) measurements of Fe base, Ni-base, and Co-base hardfacing were performed in accordance with ASTM E399-90 procedure in an effort to identify a tough cobalt-free alternative. Reduced scatter in K{sub IC} data was observed for the Fe base hardfacing, and the 95% lower bound K{sub IC} values were generally higher than the Ni-base Hardfacing alloys. Preliminary crack growth data obtained during precracking indicate that the Ni-base hardfacing possess better fatigue crack growth resistance. However, none of the Fe-base or Ni-base hardfacing have K{sub IC} values that are comparable to the reference Co-base hard facing. The test specimens were machined from thick (0.5 inches) weld deposits, and the microstructures of the test specimens are compared with the more prototypic, thinner deposits. Microstructural and fractographic examinations are used to characterize the fracture mechanisms and delineate the operative toughening mechanisms. Crack deflection and crack bridging toughening mechanisms are shown to …
Date: April 27, 1998
Creator: Cockeram, B.V.
System: The UNT Digital Library
Spin structure of the proton and large p{sub T} processes in polarized pp collisions (open access)

Spin structure of the proton and large p{sub T} processes in polarized pp collisions

QCD motivated polarized parton distributions, evolved directly in x-space, are used to predict rates for prompt photon and jet production at RHIC and HERA-N center of mass energies. Various scenarios for the polarized gluon distributions are considered and compared, and the possibility of using large p{sub T} processes in polarized pp collision experiments to choose between them is analyzed.
Date: October 27, 1998
Creator: Gordon, L. E. & Ramsey, G. P.
System: The UNT Digital Library
Safety and environmental process for the design and construction of the National Ignition Facility (open access)

Safety and environmental process for the design and construction of the National Ignition Facility

The National Ignition Facility (NIF) is a U.S. Department of Energy (DOE) laser fusion experimental facility currently under construction at the Lawrence Livermore National Laboratory (LLNL). This paper describes the safety and environmental processes followed by NIF during the design and construction activities.
Date: May 27, 1998
Creator: Brereton, S.J., LLNL
System: The UNT Digital Library
Use of alternating-Z doubling in high-dynamic-range tripling: design and evaluation of an optimized prototype tripler (open access)

Use of alternating-Z doubling in high-dynamic-range tripling: design and evaluation of an optimized prototype tripler

We designed and tested an alternating-Z tripler that consisted of two detuned, Type-1, potassium dihydrogen phosphate (KD*P) doublers and one KD*P mixer. The crystal thicknesses were, respectively, 13, 10 and 10 mm, and the detunings of the doublers were +420 and -520 µrad. All three crystals were fabricated from 80% deuterated KDP. Conversion efficiency was measured and calculated for input 1053- nm pulses with approximately rectangular waveforms and durations of either 1 or 6 ns, and for 20-ns pulses that exhibited intensity variation by a factor of 10. The measured peak conversion efficiency was more than 80%, and energy conversion efficiencies ranged from 62-80% depending on the waveform of the input pulse. The expected large dynamic range in input intensity, 9-10, was observed, and the measured and calculated efficiencies were in excellent agreement.
Date: July 27, 1998
Creator: Auerbach, J. M.; Barker, C.; Eimerl, D.; Milan, D. & Milonni, P. W.
System: The UNT Digital Library