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Plasma chemistry in wire chambers

Description: The phenomenology of wire chamber aging is discussed and fundamentals of proportional counters are presented. Free-radical polymerization and plasma polymerization are discussed. The chemistry of wire aging is reviewed. Similarities between wire chamber plasma (>1 atm dc-discharge) and low-pressure rf-discharge plasmas, which have been more widely studied, are suggested. Construction and use of a system to allow study of the plasma reactions occurring in wire chambers is reported. A proportional tube irradiated by an {sup 55}Fe source is used as a model wire chamber. Condensable species in the proportional tube effluent are concentrated in a cryotrap and analyzed by gas chromatography/mass spectrometry. Several different wire chamber gases (methane, argon/methane, ethane, argon/ethane, propane, argon/isobutane) are tested and their reaction products qualitatively identified. For all gases tested except those containing methane, use of hygroscopic filters to remove trace water and oxygen contaminants from the gas resulted in an increase in the average molecular weight of the products, consistent with results from low-pressure rf-discharge plasmas. It is suggested that because water and oxygen inhibit polymer growth in the gas phase that they may also reduce polymer deposition in proportional tubes and therefore retard wire aging processes. Mechanistic implications of the plasma reactions of hydrocarbons with oxygen are suggested. Unresolved issues in this work and proposals for further study are discussed.
Date: May 1, 1990
Creator: Wise, J.
Partner: UNT Libraries Government Documents Department

Chemistry of radiation damage to wire chambers

Description: Proportional counters are used to study aspects of radiation damage to wire chambers (wire aging). Principles of low-pressure, rf plasma chemistry are used to predict the plasma chemistry in electron avalanches (1 atm, dc). (1) Aging is studied in CF{sub 4}/iC{sub 4}H{sub 10} gas mixtures. Wire deposits are analyzed by Auger electron spectroscopy. An apparent cathode aging process resulting in loss of gain rather than in a self-sustained current is observed in CF{sub 4}-rich gases. A four-part model considering plasma polymerization of the hydrocarbon, etching of wire deposits by CF{sub 4}, acceleration of deposition processes in strongly etching environments, and reactivity of the wire surface is developed to understand anode wire aging in CF{sub 4}/iC{sub 4}H{sub 10} gases. Practical guidelines suggested by the model are discussed. (2) Data are presented to suggest that trace amounts of Freons do not affect aging rates in either dimethyl ether or Ar/C{sub 2}H{sub 6}. Apparent loss of gain is explained by attachment of primary electrons to a continuously increasing concentration of Freon 11 (CCl{sub 3}F) in the counter gas. An increase in the concentration of Freon 11 in dimethyl ether is caused by a distillation process in the gas supply bottle and is a natural consequence of the unequal volatilities of the two compounds.
Date: August 1, 1992
Creator: Wise, J.
Partner: UNT Libraries Government Documents Department

Environmental risk assessment for start-up of a new consolidated maintenance facility

Description: This paper summarizes a case study of a risk assessment for a consolidated maintenance facility (CMF). An interdisciplinary team was formed to identify and evaluate showstopper'' risks which could delay or prevent ontime, safe, and economical operation of a CMF and to recommend ways to mitigate the risks. The risk assessment was constrained by time, information, incomplete plans and facilities, and a concomitant major transition in manufacturing process, organization, and technology. Working within these constraints, the team integrated convergent findings into estimates of high, medium, and low risks based on the subjective likelihood of occurrence and predicted consequences of potential hazard events. The team also made risk-reduction recommendations for facility detail design and production start-up. The findings and recommendations reported in this study focus on risks related to environmental design and workstation ergonomics. Findings from the risk assessment effort should aid other constrained risk assessments and applied research on similar facilities.
Date: October 1, 1992
Creator: Heubach, J.G. & Wise, J.A.
Partner: UNT Libraries Government Documents Department

Human factors in environmental management: New directions from the Hanford Site

Description: Environmental management is the general term given to modern attempts to seek technological solutions to certain constrained environmental problems. it involves developing and applying new technologies that respond to changes in environmental policy. It does not eliminate the need for environmental ethics'' in society. Nor does it substitute for the fundamental changes in political and social structures that are needed for dealing with large-scale environmental issues. The scope of these issues can be illustrated by looking at the Hanford Site. Since 1943, the 560-square-mile Hanford Site in southeastern Washington state has been the production source of much of the nuclear weapons-grade radioactive materials for the United States. The legacy of 50 years of producing fissile materials has been an environmental cleanup problem of impressive proportions. In 1989, with the Cold War winding down, Secretary of Energy James Watkins established a new vision for Hanford as the flagship for waste management research.'' As plans and preparations for cleanup work proceed at the Hanford Site and around the world, the need for well-orchestrated environmental management methodologies has become increasingly apparent. In 1990, a Human Factors Engineering Group was established in the Technology Planning and Analysis Center at PNL to provide appropriate support for the Laboratory's research efforts. At an ever-increasing rate, these research efforts require integrating human performance into complex environmental technology systems. The endeavor of responding to the Laboratory's research needs has provided innovative opportunities for the application of the concept of Human Factors. Discussed are some of the major applications of Human Factors to environmental management.
Date: October 1, 1992
Creator: Wise, J.A. & Savage, S.F.
Partner: UNT Libraries Government Documents Department

Design basis for the NRC Operations Center

Description: This report documents the development of a design for a new NRC Operations Center (NRCOC). The project was conducted in two phases: organizational analysis and facility design. In order to control the amount of traffic, congestion and noise within the facility, it is recommended that information flow in the new NRCOC be accomplished by means of an electronic Status Information Management System. Functional requirements and a conceptual design for this system are described. An idealized architectural design and a detailed design program are presented that provide the appropriate amount of space for operations, equipment and circulation within team areas. The overall layout provides controlled access to the facility and, through the use of a zoning concept, provides each team within the NRCOC the appropriate balance of ready access and privacy determined from the organizational analyses conducted during the initial phase of the project.
Date: May 1, 1983
Creator: Lindell, M.K.; Wise, J.A.; Griffin, B.N.; Desrosiers, A.E. & Meitzler, W.D.
Partner: UNT Libraries Government Documents Department

General solutions for the oxidation kinetics of polymers

Description: The simplest general kinetic schemes applicable to the oxidation of polymers are presented, discussed and analyzed in terms of the underlying kinetic assumptions. For the classic basic autoxidation scheme (BAS), which involves three bimolecular termination steps and is applicable mainly to unstabilized polymers, typical assumptions used singly or in groups include (1) long kinetic chain length, (2) a specific ratio of the termination rate constants and (3) insensitivity to the oxygen concentration (e.g., domination by a single termination step). Steady-state solutions for the rate of oxidation are given in terms of one, two, three, or four parameters, corresponding respectively to three, two, one, or zero kinetic assumptions. The recently derived four-parameter solution predicts conditions yielding unusual dependencies of the oxidation rate on oxygen concentration and on initiation rate, as well as conditions leading to some unusual diffusion-limited oxidation profile shapes. For stabilized polymers, unimolecular termination schemes are typically more appropriate than bimolecular. Kinetics incorporating unimolecular termination reactions are shown to result in very simple oxidation expressions which have been experimentally verified for both radiation-initiated oxidation of an EPDM and thermoxidative degradation of nitrile and chloroprene elastomers.
Date: August 1, 1996
Creator: Gillen, K.T.; Clough, R.L. & Wise, J.
Partner: UNT Libraries Government Documents Department

NdFeB magnets aligned in a 9-T superconducting solenoid.

Description: Commercial-grade magnet powder (Magnequench UG) was uniaxial die-pressed into cylindrical compacts, while being aligned in the 1-T to 8-T DC field of a superconducting solenoid at Argonne National Laboratory. Then, the compacts were added to normal Magnequench UG production batches for sintering and annealing. The variations in magnet properties for different strengths of alignment fields are reported for 15.88-mm (5/8-in.) diameter compacts made with length-to-diameter (L/D) ratios in the range {ge} 0.25 and {le} 1. The best magnets were produced when the powder-filled die was inserted into the active field of the solenoid and then pressed. Improvements in the residual flux density of 8% and in the energy product of 16% were achieved by increasing the alignment field beyond the typical 2-T capabilities of electromagnets. The most improvement was achieved for the compacts with the smallest L/D ratio. The ability to make very strong magnets with small L/D, where self-demagnetization effects during alignment are greatest, would benefit most the production of near-final-shape magnets. Compaction of the magnet powder using a horizontal die and a continuously active superconducting solenoid was not a problem. Although the press was operated in the batch mode for this proof-of-concept study, its design is intended to enable automated production.
Date: May 8, 2002
Creator: Mulcahy, T. M.; Hull, J. R.; Rozendaal, E. & Wise, J. H.
Partner: UNT Libraries Government Documents Department

Evidence that Arrhenius high-temperature aging behavior for an EPDM o-ring does not extrapolate to lower temperatures

Description: Because of the need to significantly extend the lifetimes of weapons, and because of potential implications of environmental O-ring failure on degradation of critical internal weapon components, the authors have been working on improved methods of predicting and verifying O-ring lifetimes. In this report, they highlight the successful testing of a new predictive method for deriving more confident lifetime extrapolations. This method involves ultrasensitive oxygen consumption measurements. The material studied is an EPDM formulation use for the environmental O-ring the W88. Conventional oven aging (155 C to 111 C) was done on compression molded sheet material; periodically, samples were removed from the ovens and subjected to various measurements, including ultimate tensile elongation, density and modulus profiles. Compression stress relaxation (CSR) measurements were made at 125 C and 111 C on disc shaped samples (12.7 mm diameter by 6 mm thick) using a Shawbury Wallace Compression Stress Relaxometer MK 2. Oxygen consumption measurements were made versus time, at temperatures ranging from 160 C to 52 C, using chromatographic quantification of the change in oxygen content caused by reaction with the EPDM material in sealed containers.
Date: September 1, 1997
Creator: Gillen, K.T.; Wise, J.; Celina, M. & Clough, R.L.
Partner: UNT Libraries Government Documents Department

New method for predicting lifetime of seals from compression-stress relaxation experiments

Description: Interpretation of compression stress-relaxation (CSR) experiments for elastomers in air is complicated by (1) the presence of both physical and chemical relaxation and (2) anomalous diffusion-limited oxidation (DLO) effects. For a butyl material, the authors first use shear relaxation data to indicate that physical relaxation effects are negligible during typical high temperature CSR experiments. They then show that experiments on standard CSR samples ({approximately}15 mm diameter when compressed) lead to complex non-Arrhenius behavior. By combining reaction kinetics based on the historic basic autoxidation scheme with a diffusion equation appropriate to disk-shaped samples, they derive a theoretical DLO model appropriate to CSR experiments. Using oxygen consumption and permeation rate measurements, the theory shows that important DLO effects are responsible for the observed non-Arrhenius behavior. To minimize DLO effects, they introduce a new CSR methodology based on the use of numerous small disk samples strained in parallel. Results from these parallel, minidisk experiments lead to Arrhenius behavior with an activation energy consistent with values commonly observed for elastomers, allowing more confident extrapolated predictions. In addition, excellent correlation is noted between the CSR force decay and the oxygen consumption rate, consistent with the expectation that oxidative scission processes dominate the CSR results.
Date: June 1, 1998
Creator: Gillen, K.T.; Keenan, M.R. & Wise, J.
Partner: UNT Libraries Government Documents Department

The visual analysis of textual information: Browsing large document sets

Description: Visualization tools have been invaluable in the process of scientific discovery by providing researchers with insights gained through graphical tools and techniques. At PNL, the Multidimensional Visualization and Advanced Browsing (MVAB) project is extending visualization technology to the problems of intelligence analysis of textual documents by creating spatial representations of textual information. By representing an entire corpus of documents as points in a coordinate space of two or more dimensions, the tools developed by the MVAB team give the analyst the ability to quickly browse the entire document base and determine relationships among documents and publication patterns not readily discernible through traditional lexical means.
Date: May 1, 1995
Creator: Thomas, J.; Pennock, K.; Fiegel, T.; Wise, J.; Pottier, M.; Schur, A. et al.
Partner: UNT Libraries Government Documents Department

DOE-sponsored cable aging research at Sandia National Laboratories

Description: Cables have been identified as critical components requiring detailed technical evaluation for extending the lifetime of Light Water Reactors beyond 40 years. This paper highlights some of the DOE-sponsored cable aging studies currently underway at Sandia. These studies are focused on two important issues: the validity of the often-used Arrhenius thermal aging prediction method and methods for predicting lifetimes in combined thermal-radiation environments. Accelerated thermal aging results are presented for three cable jacket and insulation materials, which indicate that hardening of the outside surface has an Arrhenius temperature dependence and correlates well with reductions in ultimate tensile elongation. This suggests that the indentor approach is a promising NDE technique for cable jacket and unjacketed insulation materials installed in thermally-dominated regions of nuclear power plants.
Date: December 1, 1995
Creator: Gillen, K.T.; Clough, R.L.; Celina, M.; Wise, J. & Malone, G.M.
Partner: UNT Libraries Government Documents Department

Correlation of Chemical and Mechanical Property Changes During Oxidative Degradation of Neoprene

Description: The thermal degradation of a commercial, stabilized, unfilled neoprene (chloroprene) rubber was investigated at temperatures up to 140 C. The degradation of this material is dominated by oxidation rather than dehydrochlorination. Important heterogeneous oxidation effects were observed at the various temperatures investigated using infrared micro-spectroscopy and modulus profiling. Intensive degradation-related spectral changes in the IR occurred in the conjugated carbonyl and hydroxyl regions. Quantitative analysis revealed some differences in the development of the IR oxidation profiles, particularly towards the sample surface. These chemical degradation profiles were compared with modulus profiles (mechanical properties). It is concluded that the profile development is fundamentally described by a diffusion-limited autoxidation mechanism. Oxygen consumption measurements showed that the oxidation rates display non-Arrhenius behavior (curvature) at low temperatures. The current results, when compared to those of a previously studied, clay-filled commercial neoprene formulation, indicate that the clay filler acts as an antioxidant, but only at low temperatures.
Date: July 1, 1999
Creator: Celina, M.; Wise, J.; Ottesen, D.K.; Gillen, K.T. & Clough, R.L.
Partner: UNT Libraries Government Documents Department

Energy security in the post-Cold War era: Identifying future courses for crises

Description: This paper addresses US energy security in the post-Cold War era for a conference on energy security jointly sponsored by the Department of Energy and the National Defense University. It examines the evolving nature of energy security based on analysis of past crisis-inducing events and-discusses potentially important geopolitical, environmental, regulatory, and economic developments during the next twenty-five years. The paper steps beyond the traditional economic focus of energy security issues to examine the interplay between fundamental economic and technical drivers on the one hand, and political, environmental, and perceptual phenomena, on the other hand, that can combine to create crises where none were expected. The paper expands on the premise that the recent demise of the Soviet Union and other changing world conditions have created a new set of energy dynamics, and that it is imperative that the United States revise its energy security perspective accordingly. It proceeds by reviewing key factors that comprise the concepts of ``energy security`` and ``energy crisis`` and how they may fit into the new world energy security equation. The study also presents a series of crisis scenarios that could develop during the next twenty-five years, paying particular attention to mechanisms and linked crisis causes and responses. It concludes with a discussion of factors that may serve to warn analysts and decision makers of impending future crises conditions. The crisis scenarios contained in this report should be viewed only as a representative sample of the types of situations that could occur. They serve to illustrate the variety of factors that can coalesce to produce a ``crisis.``
Date: November 1, 1994
Creator: Freund, M.T.; Wise, J.A.; Ulibarri, C.A.; Shaw, B.R.; Seely, H.E. & Roop, J.M.
Partner: UNT Libraries Government Documents Department

A permanent-magnet rotor for a high-temperature superconducting bearing

Description: Design, fabrication, and performance, of a 1/3-m dia., 10-kg flywheel rotor with only one bearing is discussed. To achieve low-loss energy storage, the rotor`s segmented-ring permanent-magnet (PM) is optimized for levitation and circumferential homogeneity. The magnet`s carbon composite bands enable practical energy storage.
Date: July 1, 1995
Creator: Mulcahy, T.M.; Hull, J.R.; Uherka, K.L.; Abboud, R.G.; Wise, J.H. & Carnegie, D.W.
Partner: UNT Libraries Government Documents Department

Wind energy resource atlas. Volume 10. Alaska region

Description: This atlas of the wind energy resource is composed of introductory and background information, a regional summary of the wind resource, and assessments of the wind resource in each subregion of Alaska. Background is presented on how the wind resource is assessed and on how the results of the assessment should be interpreted. A description of the wind resource on a state scale is given. The results of the wind energy assessments for each subregion are assembled into an overview and summary of the various features of the Alaska wind energy resource. An outline to the descriptions of the wind resource given for each subregion is included. Assessments for individual subregions are presented as separate chapters. The subregion wind energy resources are described in greater detail than is the Alaska wind energy resource, and features of selected stations are discussed. This preface outlines the use and interpretation of the information found in the subregion chapters.
Date: December 1, 1980
Creator: Wise, J.L.; Wentink, T. Jr.; Becker, R. Jr.; Comiskey, A.L.; Elliott, D.L.; Barchet, W.R. et al.
Partner: UNT Libraries Government Documents Department

Design, Development and Testing of a Drillable Straddle Packer for Lost Circulation Control in Geothermal Drilling

Description: Lost Circulation is a widespread problem encountered when drilling geothermal wells, and often represents a substantial portion of the cost of drilling a well. The U.S. Department of Energy sponsors research and development work at Sandia National Laboratories in an effort to reduce these lost circulation expenditures. Sandia has developed a down hole tool that improves the effectiveness and reduces th cost of lost circulation cement treatment while drilling geothermal wells. This tool, the Drillable Straddle Packer, is a low-cost disposable device that is used to isolate the loss zone and emplace the cement treatment directly into the region of concern. This report documents the design and development of the Drillabe Straddle Packer, the laboratory and field test results, and the design package that is available to transfer this technology to industry users.
Date: April 1, 1999
Creator: Gabaldon, J.; Glowka, D.A.; Gronewald, P.; Knudsen, S.D.; Raymond, D.W.; Staller, G.E. et al.
Partner: UNT Libraries Government Documents Department

Beam-powered lunar rover design

Description: Manned exploration of our nearest neighbors in the solar systems is the primary goal of the Space Exploration Initiative (SEI). An integral part of any manned lunar or planetary outpost will be a system for manned excursions over the surface of the planet. This report presents a preliminary design for a lunar rover capable of supporting four astronauts on long-duration excursions across the lunar landscape. The distinguishing feature of this rover design is that power is provided to rover via a laser beam from an independent orbiting power satellite. This system design provides very high power availability with minimal mass on the rover vehicle. With this abundance of power, and with a relatively small power-system mass contained in the rover, the vehicle can perform an impressive suite of mission-related activity. The rover might be used as the first outpost for the lunar surface (i.e., a mobile base). A mobile base has the advantage of providing extensive mission activities without the expense of establishing a fixed base. This concept has been referred to as Rove First.'' A manned over, powered through a laser beam, has been designed for travel on the lunar surface for round-trip distances in the range of 1000 km, although the actual distance traveled is not crucial since the propulsion system does not rely on energy storage. The life support system can support a 4-person crew for up to 30 days, and ample power is available for mission-related activities. The 8000-kg rover has 30 kW of continuous power available via a laser transmitter located at the Earth-moon L1 libration point, about 50,000 km above the surface of the moon. This rover, which is designed to operate in either day or night conditions, has the flexibility to perform a variety of power-intensive missions. 24 refs.
Date: March 1, 1992
Creator: Dagle, J.E.; Coomes, E.P.; Antoniak, Z.I.; Bamberger, J.A.; Bates, J.M.; Chiu, M.A. et al.
Partner: UNT Libraries Government Documents Department