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  Partner: UNT Libraries Government Documents Department
 Decade: 1990-1999
3D visualization of port simulation.
Affordable and realistic three dimensional visualization technology can be applied to large scale constructive simulations such as the port simulation model, PORTSIM. These visualization tools enhance the experienced planner's ability to form mental models of how seaport operations will unfold when the simulation model is implemented and executed. They also offer unique opportunities to train new planners not only in the use of the simulation model but on the layout and design of seaports. Simulation visualization capabilities are enhanced by borrowing from work on interface design, camera control, and data presentation. Using selective fidelity, the designers of these visualization systems can reduce their time and efforts by concentrating on those features which yield the most value for their simulation. Offering the user various observational tools allows the freedom to simply watch or engage in the simulation without getting lost. Identifying the underlying infrastructure or cargo items with labels can provide useful information at the risk of some visual clutter. The PortVis visualization expands the PORTSIM user base which can benefit from the results provided by this capability, especially in strategic planning, mission rehearsal, and training. Strategic planners will immediately reap the benefits of seeing the impact of increased throughput visually without keeping track of statistical data. Mission rehearsal and training users will have an effective training tool to supplement their operational training exercises which are limited in number because of their high costs. Having another effective training modality in this visualization system allows more training to take place and more personnel to gain an understanding of seaport operations. This simulation and visualization training can be accomplished at lower cost than would be possible for the operational training exercises alone. The application of PORTSIM and PortVis will lead to more efficient planning overall and ultimately increase port utilization and throughput, decreasing the amount of time required to transport cargo from its origin to its final destination.
4th generation light source instrumentation.
This working group on 4th Generation Light Source (4GLS) Instrumentation was a follow-up to the opening-discussion on Challenges in Beam Profiling. It was in parallel with the Feedback Systems session. We filled the SSRL Conference Room with about 25 participants. The session opened with an introduction by Lumpkin. The target beam parameter values for a few-angstrom, self-amplified spontaneous emissions (SASE) experiment and for a diffraction-limited soft x-ray storage ring source were addressed. Instrument resolution would of course need to be 2-3 times better than the value measured, if possible. The nominal targeted performance parameters are emittance (1-2{pi} mm mrad), bunch length (100 fs), peak-current (l-5 kA), beam size (10 {micro}m), beam divergence (1 {micro}rad), energy spread (2 x 10{sup {minus}4}), and beam energy (10's of GeV). These are mostly the SASE values, and the possible parameters for a diffraction-limited soft x-ray source would be relaxed somewhat. Beam stability and alignment specifications in the sub-micron domain for either device are anticipated.
8th International symposium on transport phenomena in combustion
The 8th International Symposium on Transport Phenomena in Combustion will be held in San Francisco, California, U.S.A., July 16-20, 1995, under the auspices of the Pacific Center of Thermal-Fluids Engineering. The purpose of the Symposium is to provide a forum for researchers and practitioners from around the world to present new developments and discuss the state of the art and future directions and priorities in the areas of transport phenomena in combustion. The Symposium is the eighth in a series; previous venues were Honolulu 1985, Tokyo 1987, Taipei 1988, Sydney 1991, Beijing 1992, Seoul 1993 and Acapulco 1994, with emphasis on various aspects of transport phenomena. The current Symposium theme is combustion. The Symposium has assembled a balanced program with topics ranging from fundamental research to contemporary applications of combustion theory. Invited keynote lecturers will provide extensive reviews of topics of great interest in combustion. Colloquia will stress recent advances and innovations in fire spread and suppression, and in low NO{sub x} burners, furnaces, boilers, internal combustion engines, and other practical combustion systems. Finally, numerous papers will contribute to the fundamental understanding of complex processes in combustion. This document contains abstracts of papers to be presented at the Symposium.
950809 Charged particle transport updated multi-group diffusion
In 1974, a charged particle transport scheme was introduced which utilized a multi-group diffusion method for the spatial transport and slowing down of energetic ions in a hot plasma. In this treatment a diffusion coefficient was used which was flux-limited to provide, hopefully, some degree of accuracy when the slowing down of an energetic charged particle is dominated by Coulomb collisions with thermal ions and electrons in a plasma medium. An advantage of this method was a very fast, memory-contained program for calculating the behavior of energetic charged particles which resulted in smoothly varying particle number densities and energy depositions. The main limitation of the original multi-group charged particle diffusion scheme is its constraint to a basic ten group structure; the same ten group structure for each of the five energetic ions tracked. This is regarded as a severe limitation, inasmuch as more groups would be desired to simulate more accurately the corresponding Monte Carlo results of energies deposited over spatial zones from a charged particle source. More generally, it seems preferable to have a different group structure for each particle type since they are created at inherently different energies. In this paper, the basic theory and multi-group description will be given. This is followed by the specific techniques that were used to solve the resultant equations. Finally, the modifications that were made to the cross section data as well as the methods used for energy and momentum deposition are described.
Ab initio and density functional studies of hydrocarbon adsorption in zeolites.
The adsorption energies of methane and ethane in zeolites are investigated with ab initio molecular orbital theory and density functional theory. In this work we have used zeolite cluster models containing two, three, and five tetrahedral (Si, Al) atoms and have found equilibrium structures for complexes of methane, ethane, and propane with an acid site. If a large enough cluster is used and correlation effects are included via perturbation theory, the calculated adsorption energy for ethane is about 5 kcal/mol compared with the experimental value of 7.5 kcal/mol. The B3LYP density functional method gives a much smaller binding of {approximately}1 kcal/mol for ethane. The reason for the failure of density fictional theory is unclear.
Ab initio calculation of electron excitation energies in solids
Progress in the first-principles calculation of electron excitation energies in solids is discussed. Quasiparticle energies are computed by expanding the electron self energy to first order in the screened Coulomb interaction in the so-called GW approximation. The method was applied to explain and predict spectroscopic properties of a variety of systems. Several illustrative applications to semiconductors, materials under pressure, chemisorption, and point defects in solids are presented. A recent reformulation of the method employing mixed- space functions and imaginary time techniques is also discussed.
Ab initio Monte Carlo investigation of small lithium clusters.
Structural and thermal properties of small lithium clusters are studied using ab initio-based Monte Carlo simulations. The ab initio scheme uses a Hartree-Fock/density functional treatment of the electronic structure combined with a jump-walking Monte Carlo sampling of nuclear configurations. Structural forms of Li{sub 8} and Li{sub 9}{sup +} clusters are obtained and their thermal properties analyzed in terms of probability distributions of the cluster potential energy, average potential energy and configurational heat capacity all considered as a function of the cluster temperature. Details of the gradual evolution with temperature of the structural forms sampled are examined. Temperatures characterizing the onset of structural changes and isomer coexistence are identified for both clusters.
The Abandoned Mine Land Fund: Grants Distribution and Issues
The Surface Mining Control and Reclamation Act (SMCRA, P.L. 95-87), enacted in 1977, established reclamation standards for all coal surface mining operations, and for the surface effects of underground mining. It also established the Abandoned Mine Land (AML) program to promote the reclamation of sites mined and abandoned prior to the enactment of SMCRA. To finance reclamation of abandoned mine sites, the legislation established fees on coal production. These collections are divided into federal and state shares; subject to annual appropriation, AML funds are distributed annually to states with approved reclamation programs. This report describes the distribution of these funds and the various issues that arise from said distribution.
Ablative material removal utilizing the copper vapor laser
Short communication.
Abortion Procedures
The Partial-Birth Abortion Ban Act of 1997, H.R. 1122 was vetoed by President Clinton on October 10, 1997. This legislation would have made it a federal crime, punishable by fine and/or incarceration, for a physician to perform a partial birth abortion unless it was necessary to save the life of a mother whose life is endangered by a physical disorder, illness, or injury. The partial-birth abortion legislation has stimulated a great deal of controversy. This report provides a brief overview of the abortion methods currently in use for which data have been published and some positions on the partial birth abortion legislation.
Above and beyond basic public participation
This paper evolved out of a discussion about public participation as it is currently being brought to the fore-front of clean-up activities at hazardous waste sites. There exists much official and unofficial documentation pertaining to the need for public involvement. The purposes for public involvement efforts in Environmental Restoration are: to enable substantive input to the clean-up process; methods for establishing formal, and now informal, mechanisms for public input and awareness of on-going facility activities; and the opening of better channels for communication and conflict resolution between the public and the facility. This presentation will briefly outline the regulatory approach for public outreach because many of these terms are used with such frequency, their meanings tend to get forgotten or misconstrued. Then, the authors will critique the most common methods for conducting public involvement as attempted through advisory boards and public meetings. For illustrative purposes, they will be referring to the site they are most familiar with, which is Los Alamos National Laboratory (LANL).
ABS plastic RPCs
After investigating a number of materials, we discovered that an ABS plastic doped with a conducting polymer performs well as the resistive electrode in a narrow gap RPC (resistive plate chamber). Operating in the streamer mode, we find efficiencies of 90-96% with low noise and low strip multiplicities. We have also studied a variety of operating gases and found that a mixture containing SF{sub 6}, a non-ozone depleting gas, argon and isobutane gives good streamer mode performance, even with isobutane concentrations of 20% or less.
Absence of second stability in ATF
Ideal Mercier and ballooning modes for three-dimensional (3-D) equilibria of the Advanced Toroidal Facility (ATF) are studied in detail. These modes are found to introduce instability limits at modest beta values for pressure profiles for which previous results, based on a two-dimensional (2-D) equilibrium approximation, predicted the existence of a second stability region. This absence of second stability is in agreement with an analysis by Cooper et al. who used a simplified model for the ATF plasma boundary. The increased instability is found to result from the 3-D feature of the Pfirsch-Schlueter current. Furthermore, a strong quadrupole field is found to decrease the beta limit of these modes, contrary to the results obtained using the 2-D equilibria. Although direct comparison with measured beta values is not possible owing to the absence of profile data for ATF plasmas, pressure profiles used previously to model ATF data as well as in the 2-D analysis are used to obtain the results. The details of the pressure profiles and the plasma configurations strongly influence the stability limits on average beta which remains below 3%.
Absolute Intensities of the Vacuum Ultraviolet Spectra in a Metal-Etch Plasma Processing Discharge
In this paper we report absolute intensities of vacuum ultraviolet and near ultraviolet emission lines (4.8 eV to 18 eV ) for aluminum etching discharges in an inductively coupled plasma reactor. We report line intensities as a function of wafer type, pressure, gas mixture and rf excitation level. IrI a standard aluminum etching mixture containing C12 and BC13 almost all the light emitted at energies exceeding 8.8 eV was due to neutral atomic chlorine. Optical trapping of the WV radiation in the discharge complicates calculations of VUV fluxes to the wafer. However, we see total photon fluxes to the wailer at energies above 8.8 eV on the order of 4 x 1014 photons/cm2sec with anon- reactive wafer and 0.7 x 10 `4 photons/cm2sec with a reactive wtier. The maj ority of the radiation observed was between 8.9 and 9.3 eV. At these energies, the photons have enough energy to create electron-hole pairs in Si02, but may penetrate up to a micron into the Si02 before being absorbed. Relevance of these measurements to vacuum-W photon-induced darnage of Si02 during etching is discussed.
Absorbed dose from 7-GeV bremsstrahlung in a PMMA phantom.
Electron storage rings generate energetic bremsstrahlung photons through radiative interaction of the particle beam with the residual gas molecules and other components inside the storage ring. At the Advanced Photon Source (APS), where the stored beam energy is 7 GeV, bremsstrahlung generated in the straight sections of the insertion devices comes down through the beamlines. The resulting absorbed dose distributions by, this radiation in a 300 mm x 300 mm x 300 mm tissue substitute phantom were measured with LiF:Mg,Ti (TLD-700) thermoluminescent dosimeters. The average normalized absorbed dose, in a cross sectional area of 100 mm{sup 2} at a depth of 150 mm of the PMMA phantom, was measured as 3.3 x 10{sup 6} mGy h{sup {minus}1}W{sup {minus}1} for a 7-GeV bremsstrahhmg spectrum.
Absorption of laser light in overdense plasmas by sheath inverse bremsstrahlung
The original sheath inverse bremsstrahlung model [P. J. Catto and R. M. More, 1977] is modified by including the vxB term in the equation of motion. It is shown that the present results axe significantly different from those derived without the vxB term. The vxB term is also important in interpreting the absorption mechanism. If the vxB term were neglected, the absorption of the light would be incorrectly interpreted as an increase in the transverse electron temperature. This would violate the conservation of the transverse components of the canonical momentum, in the case of a normally incident laser light. It is also shown that both the sheath inverse bremsstrahlung and the anomalous skin effect are limiting cases of the same collisionless absorption mechanism. Finally, results from PIC plasma simulations are compared with the absorption coefficient calculated from the linear theory.
Absorption spectra and speciation of plutonium(VI) with phosphate
Plutonium(VI)-phosphate species in aqueous solution, at pH < 2.4, formed two species: PuO{sub 2}H{sub 2}PO{sub 4}{sup +} (characterized by an 835 nm absorption band) and the solid phase PuO{sub 2}(H{sub 2}PO{sub 4}){sub 2}. The stability constant {beta} for the PuO{sub 2}H{sub 2}PO{sub 4}{sup +} species was determined to be log {beta} = 2.1 {+-} 0.1 (ionic strength = 0.6--0.9 M) and log {beta}{sup T} = 2.6 {+-} 0.15 (zero ionic strength). Four Pu(VI)-phosphate species (absorption bands at 842, 846, 857, and 866 nm) formed at pH = 2.4 to 12.2 and are characterized by polynuclear behavior, the formation of precipitates, and colloidal properties. The 842 and 846 nm species are believed to be [PuO{sub 2}(HPO{sub 4}){sub m}]{sub n} and [PuO{sub 2}(NaPO{sub 4}){sub m}]{sub n}. The 857 and 866 nm species area as yet unidentified. The speciation of plutonium with phosphate is of interest to radionuclide migration studies because phosphate is present in many groundwaters and may be used as an actinide getter in nuclear waste disposal. An actinide getter is a complexing agent that forms insoluble phases with actinides, thereby reducing their migration.
Absorption spectroscopy characterization measurements of a laser-produced Na atomic beam
This work describes a pulsed Na atomic beam source developed for spectroscopic diagnosis of a high-power ion diode on the Particle Beam Fusion Accelerator II. The goal is to produce a {approximately} 10{sup 12}-cm{sup {minus}3}-density Na atomic beam that can be injected into the diode acceleration gap to measure electric and magnetic fields from the Stark and Zeeman effects through laser-induced-fluorescence or absorption spectroscopy. A {approximately} 10 ns fwhm, 1.06 {micro}m, 0.6 J/cm{sup 2} laser incident through a glass slide heats a Na-bearing thin film, creating a plasma that generates a sodium vapor plume. A {approximately} 1 {micro}sec fwhm dye laser beam tuned to 5,890 {angstrom} is used for absorption measurement of the Na I resonant doublet by viewing parallel to the film surface. The dye laser light is coupled through a fiber to a spectrograph with a time-integrated CCD camera. A two-dimensional mapping of the Na vapor density is obtained through absorption measurements at different spatial locations. Time-of-flight and Doppler broadening of the absorption with {approximately} 0.1 {angstrom} spectral resolution indicate that the Na neutral vapor temperature is about 0.5 to 2 eV. Laser-induced-fluorescence from {approximately} 1 {times} 10{sup 12}-cm{sup {minus}3} Na I 3s-3p lines observed with a streaked spectrograph provides a signal level sufficient for {approximately} 0.06 {angstrom} wavelength shift measurements in a mock-up of an ion diode experiment.
Abstract and research accomplishments of University Coal Research Projects
The Principal Investigators of the grants supported by the University Coal Research Program were requested to submit abstracts and highlight accomplishments of their respective projects in time for distribution at a conference on June 13--14, 1995 at Tennessee State University in Nashville, Tennessee. This book is a compilation of the material received in response to that request. For convenience, the 70 grants reported in this book are stored into eight technical areas, Coal Science, Coal Surface Science, Reaction Chemistry, Advanced Process Concepts, Engineering Fundamentals and Thermodynamics, Environmental Science, high Temperature Phenomena, and Special topics. Indexes are provided for locating projects by subject, principal investigators, and contracting organizations. Each extended abstract describes project objectives, work accomplished, significance to the Fossil Energy Program, and plans for the next year.
An abstract approach to music.
In this article we have outlined a formal framework for an abstract approach to music and music composition. The model is formulated in terms of objects that have attributes, obey relationships, and are subject to certain well-defined operations. The motivation for this approach uses traditional terms and concepts of music theory, but the approach itself is formal and uses the language of mathematics. The universal object is an audio wave; partials, sounds, and compositions are special objects, which are placed in a hierarchical order based on time scales. The objects have both static and dynamic attributes. When we realize a composition, we assign values to each of its attributes: a (scalar) value to a static attribute, an envelope and a size to a dynamic attribute. A composition is then a trajectory in the space of aural events, and the complex audio wave is its formal representation. Sounds are fibers in the space of aural events, from which the composer weaves the trajectory of a composition. Each sound object in turn is made up of partials, which are the elementary building blocks of any music composition. The partials evolve on the fastest time scale in the hierarchy of partials, sounds, and compositions. The ideas outlined in this article are being implemented in a digital instrument for additive sound synthesis and in software for music composition. A demonstration of some preliminary results has been submitted by the authors for presentation at the conference.
Abstracts of the third international conference on the solid-state lasers for application to inertial confinement fusion
No abstract prepared.
He abundance variations in the solar wind: Observations from Ulysses
The Ulysses mission is providing the first opportunity to observe variations in solar wind plasma parameters at heliographic latitudes far removed from the ecliptic plane. We present an overview of the solar wind speed and the variability in helium abundance, [He] data on [He] in six high latitude coronal mass ejections (CMEs), and a superposed epoch analysis of [He] variations at the seven heliospheric current sheet (HCS) crossings made during the rapid-latitude-scan portion of the mission. The differences in the variability of the solar wind speed and [He] in high latitude and equatorial regions are quite striking. Solar wind speed is generally low but highly variable near the solar equator, while at higher latitudes the average speed is quite high with little variability. [He] can vary over nearly two decades at low solar latitudes, while at high latitudes it varies only slightly. In contrast to the high [He] that is commonly associated with CMEs observed in the ecliptic, none of the six high-speed CMEs encountered at high southern heliographic latitudes showed any significant variation in helium content. A superposed epoch analysis of the [He] during all seven HCS crossings made as Ulysses passed from the southern to northern solar hemisphere shows the expected [He] minimum near the crossing and a broad region of low [He] around the crossing time. We discuss how our solar wind [He] observations may provide an accurate measure of the helium composition for the entire convective zone of the Sun.
AC 95 - selected readings
Reports are presented on energy efficiency and conservation in residential buildings. Topics include housing and energy linkages; the people factor; low-income initiatives; green visions; utility programs; affordable comfort; housing as a system; and pressures and air flow in buildings.
AC losses in Bi-2223 tapes and in the 1-kA transmission line model.
We present here results of our study of the 5-m-long AC transmission tine model with 1 kA current capability at 77 K. Primary attention was paid to the current characteristics and AC losses in individual tapes and in the core of the cable. The losses were measured as a function of AC magnetic field amplitude in various orientations of magnetic field with respect to the plane of the tape and filaments. Hysteresis losses were. close to the losses in the AC regime, meaning that eddy current losses in tapes may be neglected when compared with hysteresis losses. We designed and constructed a 5-m-long model of the AC transmission line using multi filamentary Bi-2223 tapes. The current core of the model contains 120 tapes for the forward line and 120 tapes for the backward line. The AC losses in the current core were substantially greater than those seen in the individual tapes. The reason for this is related to a complex magnetic field distribution inside the current core.
Accelerated aging of EPDM and butyl elastomers
This study was composed of three parts: a post cure study to optimize final properties of an ethylene-propylene-diene (EPDM) formulation, an accelerated aging study to compare the stress relaxation behavior of a butyl and an EPDM elastomer under compression, and a cursory evaluation of a new 70 Shore A EPDM. The optimum postcure for the EPDM was found to be 2 to 4 hours at 182{degrees}C in a vacuum. The EPDM was also shown to have superior aging characteristics compared to the butyl and is recommended for use instead of the butyl material. The physical properties for new 70 Shore A EPDM are satisfactory, and the stress relaxation behavior was only slightly inferior to the other EPDM.
Accelerated degradation studies of MEH-PPV
MEH-PPV, which normally has a reddish color, is well known to show photobleaching problems. The photobleaching can be greatly accelerated by exposure to laser light while in air. For example, shining 457 mn light of relatively low intensity (0.06 W/cm{sup 2}) on the MEH-PPV causes the photoluminescence to decrease by a factor of two within a few seconds of exposure, and to show a nearly complete bleaching of the material within 30 minutes. The degradation rate is strongly influenced by laser power, sample thickness, oxygen exposure during preparation and spinning, as well as the oxygen environment during the measurement. The photobleach is indicative of one class of degradation mechanisms limiting the usefulness of PPV based polymers in electroluminescent devices. MEH-PPV which was spin coated in a nitrogen environment and measured in vacuum showed no measurable photo-chemical degradation for measuring times of up to several hours. A dramatic decrease in PL intensity was observed, however, in the presence of oxygen, as well as in samples spin coated in air, but measured in vacuum. We present data on the PL of MEH-PPV, as a function of oxygen concentration.
Accelerated life-time testing and resistance degradation of thin-film decoupling capacitors
Resistance degradation in PZT thin-film capacitors has been studied as a function of applied voltage, temperature, and film composition. It is found that the mean-time-to-failure (life-time or t{sub f}) of the capacitors shows a power law dependence on applied voltage of he form t{sub f} {proportional_to} V{sup {minus}n} (n {approximately} 4--5). The capacitor life-time also exhibits a temperature dependence of the form t{sub f} {proportional_to} exp(E{sub a}/kT), with an activation energy of {approximately} 0.8 eV. The steady-state leakage current in these samples appears to be bulk controlled. The voltage, temperature, and polarity dependence of the leakage current collectively suggest a leakage current mechanism most similar to a Frenkel-Poole process. The life-time and leakage current of the Nb-doped PZT films are superior to the undoped PZT films. This result can be explained based on the point-defect chemistry of the PZT system. Finally, the results indicate that the Nb-doped PZT films meet the essential requirements for decoupling capacitor applications.
Accelerated screening methods for determining chemical and thermal stability of refreigerant-lubricant mixtures. Part II: Experimental comparison and verification of methods. Final report, volume I
The research reported herein was performed to develop an accelerated screening method for determining the chemical and thermal stabilities of refrigerant/lubricant mixtures. The developed screening method was designed to be safe and to produce accelerated stability rankings that are in agreement with the rankings determined by the current test, Sealed Glass Tube Method to Test the Chemical Stability of Material for Use Within Refrigerant Systems, ANSI/ASHRAE Method 97-1989. The accelerated screening test developed was designed to be independent of refrigerant and lubricant compositions and to be used with a wide variety of construction materials. The studied refrigerants included CFC-11, CFC-12, HCFC-22, HFC-134a, and HFC-32/HFC-134a (zeotrope 30:70 by weight). The studied lubricants were selected from the chemical classes of mineral oil, alkylbenzene oil, polyglycols, and polyolesters. The work reported herein was performed in three phases. In the first phase, previously identified thermal analytical techniques were evaluated for development into an accelerated screening method for refrigerant/lubricant mixtures. The identified thermal analytical techniques used in situ measurements of color, temperature, or conductivity to monitor the degradation of the heated refrigerant/lubricant mixtures. The identified thermal analytical techniques also used catalysts such as ferric fluoride to accelerate the degradation of the heated refrigerant/lubricant mixtures. The thermal analytical technique employing in situ conductivity measurements was determined to be the most suitable for development into an accelerated screening method.
Accelerated screening methods for determining chemical and thermal stability of refrigerant-lubricant mixtures, Part II: Experimental comparison and verification of methods. Volume 2, In situ conductivity data
Data are presented for the accelerated screening methods for determining chemical and thermal stability of refrigerant-lubricant mixtures.
Accelerated test methods for life prediction of hermetic motor insulation systems exposed to alternative refrigerant/lubricant mixtures. Phase 3: Reproducibility and discrimination testing. Final report
In 1992, the Air-Conditioning and Refrigeration Technology Institute, Inc. (ARTI) contracted Radian Corporation to ascertain whether an improved accelerated test method or procedure could be developed that would allow prediction of the life of motor insulation materials used in hermetic motors for air-conditioning and refrigeration equipment operated with alternative refrigerant/lubricant mixtures. This report presents the results of phase three concerning the reproducibility and discrimination testing.
Accelerated tests for bounding the low dose rate radiation response of lateral PNP bipolar junction transistors
Low dose rate gain degradation of lateral pnp bipolar transistors can be simulated by accelerated irradiations performed at approximately 135 degrees C. Degradation enhancement is explained by temperature- dependent radiation-induced interface trap formation above the transistor`s base.
Accelerated thermal recovery for flash-lamp-pumped solid-state laser amplifiers final report for 97-ERD-133
We have developed a cost-effective method for accelerating the thermal wavefront recovery and shot rate of large, flashlamp-pumped, Nd:glass, Brewster-angle slab lasers of the type used for studying inertial confinement fusion (ICF) and laser-plasma interactions. This method removes waste pump heat by flowing slightly-chilled, turbulent gas over the flashlamps and blastshields after each shot, with the cooled blastshields serving as heat sinks for radiatively extracting residual heat deposited in the laser slabs. We performed both experiments and modeling to characterize residual optical distortions arising from both temperature gradients within the laser slabs as well as from buoyantly-driven convection currents in the amplifier cavity and attached beam tubes. The most rapid thermal recovery was achieved by reducing the temperature of the cooling gas by 0.5-1 C below the ambient temperature for about two hours after the shot. Model predictions for the 1.8-MJ National Ignition Facility (NIF) laser now being built at Lawrence Livermore National Laboratory (LLNL) show that such chilled-gas cooling would increase the thermal-distortion-limited shot rate from about one shot every eight hours to one shot every three to four hours, thus significantly increasing the potential scientific productivity of this major Department of Energy (DOE) facility.
Accelerating polarized beams at the AGS
The acceleration of polarized beams in circular accelerators is complicated by the presence of numerous depolarizing resonances. During acceleration, a depolarizing resonance is crossed whenever the spin precession frequency equals the frequency with which spin-perturbing magnetic fields are encountered. There are two main types of depolarizing resonances corresponding to the possible sources of such fields: imperfection resonances, which are driven by magnet errors and misalignments, and intrinsic resonances, driven by the focusing fields. The resonance conditions are usually expressed in terms of the spin tune {nu}{sub s}, which is defined as the number of spin precessions per revolution. For an ideal planar accelerator, where orbiting particles experience only the vertical guide field, the spin tune is equal to G{gamma}, where G = 1.7928 is the anomalous magnetic moment of the proton and {gamma} is the relativistic Lorentz factor. The resonance condition for imperfection depolarizing resonances arise when {nu}{sub s} = G{gamma} = n, where n is an integer. Imperfection resonances are therefore separated by only 523 MeV energy steps. The condition for intrinsic resonances is {nu}{sub s} = G{gamma} = kP {+-} {nu}{sub y}, where k is an integer, {nu}{sub y} is the vertical betatron tune and P is the superperiodicity. For the AGS, P = 12 and {nu}{sub y} {approx} 8.8. For most of the time during the acceleration cycle, the precession direction, or stable spin direction, coincides with the main vertical magnetic field. Close to a resonance, the stable spin direction is perturbed away from the vertical direction by the resonance driving fields. When a polarized beam is accelerated through an isolated resonance, the final polarization can be calculated analytically.
Acceleration to collisions for the {mu}{sup +}-{mu}{sup {minus}} collider
The authors discuss the problem of transforming muon beam bunches from a low-energy cooled state (E{sub {mu}} {approximately} 1 GeV) to short, high-energy bunches matched to high-energy collision conditions (E{sub {mu}} {approximately} 2 TeV). In this process the beam energy must increase by {approximately} three orders of magnitude, while the bunch length must be reduced by {approximately} two orders of magnitude (to {approximately} 3mm), while beam emittance dilution and beam losses, particularly through decay, must be minimized. From general considerations, they discuss possible acceleration scenarios including rapid-cycling synchrotron and recirculating linac options. The presently favored choice is a multi-stage recirculating linac system, which is discussed, and initial simulations of possible scenarios are presented. Future directions for development are discussed.
Accelerator development for a radioactive beam facility based on ATLAS.
The existing superconducting linac ATLAS is in many respects an ideal secondary beam accelerator for an ISOL (Isotope separator on-line) type radioactive beam facility. Such a facility would require the addition of two major accelerator elements: a low charge state injector for the existing heavy ion linac, and a primary beam accelerator providing 220 MV of acceleration for protons and light ions. Development work for both of these elements, including the option of superconducting cavities for the primary beam accelerator is discussed.
Accelerator developments since the ZGS by ZGS people
The ZGS was a facility, as well as an organization, where people got together to pursue a common goal of doing exciting science of the day. In this note, the authors describe notable events related to accelerators and accelerator people since the closing of the ZGS program some 15 years ago. Many of the same ZGS people have been carrying out the state-of-the art accelerator work around the Laboratory with the same dedication that characterized their work in the earlier days. First the authors describe how the activities were re-organized after the closing of the ZGS, the migration of people, and the organizational evolution since that time. Doing this shows the similarity between the birth of the ZGS and the birth of the Advanced Photon Source (APS). Then, some of the accelerator work by the former ZGS people are described. These include: (1) Intense Pulsed Neutron Source (IPNS), (2) GeV Electron Microtron (GEM), (3) Wake Field Accelerator Test Facility, (4) Advanced Photon Source, and (5) IPNS Upgrade.
Accelerator mass spectrometry as a bioanalytical tool
This paper presents data that supports Accelerator Mass Spectrometry (AMS) as a valid bioanalytical tool for tracing long lived radioisotopes in uses as molecular labels or elemental tracers.
Accelerator operation management using objects
Conflicts over control of shared devices or resources in an accelerator control system, and problems that can occur due to applications performing conflicting operations, are usually resolved by accelerator operators. For these conflicts to be detected by the control system, a model of accelerator operation must be available to the system. The authors present a design for an operation management system addressing the issues of operations management using the language of Object-Oriented Design (OOD). A possible implementation using commercially available software tools is also presented.
Accelerator Physics Challenges for Future Linear Colliders
At the present time, there are a number of future linear collider designs with a center-of-mass energy of 500 GeV or more with luminosities in excess of 10{sup -34}cm{sup -2}s{sup -1} . Many of these designs are at an advanced state of development. However, to attain the high luminosity, the colliders require very small beam emittances, strong focusing, and very good stability. In this paper, some of the outstanding issues related to producing and maintaining the small beam sizes are discussed. Although the different designs are based on very different rf technologies, many of these problems are common.
Accelerator production of tritium authorization basis strategy
The Accelerator Production of Tritium (APT) project has proposed a strategy to develop the APT authorization basis and safety case based on DOE orders and fundamental requirements for safe operation. The strategy is viable regardless of whether the APT is regulated by DOE or by an external regulatory body. Currently the operation of Department of Energy (DOE) facilities is authorized by DOE and regulated by DOE orders and regulations while meeting the environmental protection requirements of the Environmental Protection Agency (EPA) and the states. In the spring of 1994, Congress proposed legislation and held hearings related to requiring all DOE operations to be subject to external regulation. On January 25, 1995, DOE, with the support of the White House Council on Environmental Quality, created the Advisory Committee on External Regulation of Department of Energy Nuclear Safety. This committee divided its recommendations into three areas: (1) facility safety, (2) worker safety, and (3) environmental protection. In the area of facility safety the committee recommended external regulation of DOE nuclear facilities by either the Nuclear Regulatory Commission (NRC) or a restructured Defense Nuclear Facilities Safety Board (DNFSB). In the area of worker safety, the committee recommended that the Occupational Safety and Health Administration (OSHA) regulate DOE nuclear facilities. In the environmental protection area, the committee did not recommend a change in the regulation by the EPA and the states of DOE nuclear facilities. If these recommendations are accepted, all DOE nuclear facilities will be impacted to some extent.
Accelerator Production of Tritium/Low Energy Demonstration Accelerator/Coupled-Cavity Drift Tube LINAC (APT/LEDA/CCDTL) Low Beta "Hot Model" Vacuum System
No Description
Accelerator Production of Tritium Programmatic Environmental Impact Statement Input Submittal
The Programmatic Environmental Impact Statement for Tritium Supply and Recycling considers several methods for the production of tritium. One of these methods is the Accelerator Production of Tritium. This report summarizes the design characteristics of APT including the accelerator, target/blanket, tritium extraction facility, and the balance of plant. Two spallation targets are considered: (1) a tungsten neutron-source target and (2) a lead neutron-source target. In the tungsten target concept, the neutrons are captured by the circulating He-3, thus producing tritium; in the lead target concept, the tritium is produced by neutron capture by Li-6 in a surrounding lithium-aluminum blanket. This report also provides information to support the PEIS including construction and operational resource needs, waste generation, and potential routine and accidental releases of radioactive material. The focus of the report is on the impacts of a facility that will produce 3/8th of the baseline goal of tritium. However, some information is provided on the impacts of APT facilities that would produce smaller quantities.
Accelerator Production of Tritium project process waste assessment
DOE has made a commitment to compliance with all applicable environmental regulatory requirements. In this respect, it is important to consider and design all tritium supply alternatives so that they can comply with these requirements. The management of waste is an integral part of this activity and it is therefore necessary to estimate the quantities and specific wastes that will be generated by all tritium supply alternatives. A thorough assessment of waste streams includes waste characterization, quantification, and the identification of treatment and disposal options. The waste assessment for APT has been covered in two reports. The first report was a process waste assessment (PWA) that identified and quantified waste streams associated with both target designs and fulfilled the requirements of APT Work Breakdown Structure (WBS) Item This second report is an expanded version of the first that includes all of the data of the first report, plus an assessment of treatment and disposal options for each waste stream identified in the initial report. The latter information was initially planned to be issued as a separate Waste Treatment and Disposal Options Assessment Report (WBS Item
Accelerator scenario and parameters for the first muon collider and front-end of a muon collider
No abstract available.
Accelerators for high energy physics research
A brief survey of particle accelerators as research tools for high energy physics is given. The survey includes existing accelerators, as well as those envisioned for the future.
Acceptable Knowledge Summary Report for Waste Stream: SR-T001-221F-HET/Drums
Since beginning operations in 1954, the Department of Energy's Savannah River Site FB-Line conducted atomic energy defense activities consistent with the listing in Section 10101(3) of the Nuclear Waste Policy Act of 1982. The facility mission was to process and convert dilute plutonium solution into highly purified weapons grade plutonium metal. As a result of various activities conducted in support of the mission (e.g., operation, maintenance, repair, clean up, and facility modifications), the facility generated transuranic waste. This document, along with referenced supporting documents, provides a defensible and auditable record of acceptable knowledge for one of the waste streams from the FB-Line. The waste was packaged in 55-gallon drums, then shipped to the transuranic waste storage facility in ''E'' area of the Savannah River Site. This acceptable knowledge report includes information relating to the facility's history, configuration,equipment, process operations, and waste management practices.
Acceptable standard format and content for the fundamental nuclear material control (FNMC) plan required for low-enriched uranium facilities. Revision 2
This report documents a standard format suggested by the NRC for use in preparing fundamental nuclear material control (FNMC) plans as required by the Low Enriched Uranium Reform Amendments (10CFR 74.31). This report also describes the necessary contents of a comprehensive plan and provides example acceptance criteria which are intended to communicate acceptable means of achieving the performance capabilities of the Reform Amendments. By using the suggested format, the licensee or applicant will minimize administrative problems associated with the submittal, review and approval of the FNMC plan. Preparation of the plan in accordance with this format Will assist the NRC in evaluating the plan and in standardizing the review and licensing process. However, conformance with this guidance is not required by the NRC. A license applicant who employs a format that provides a equal level of completeness and detail may use their own format. This document is also intended for providing guidance to licensees when making revisions to their FNMC plan.
Acceptance criteria for non-destructive examination of double-shell tanks
This supporting document provides requirements for acceptance of relevant indications found during non-destructive examination of double-shell tanks (DSTs) at Hanford 200 areas. Requirements for evaluation of relevant indications are provided to determine acceptability of continued safe operation of the DSTs. Areas of the DSTs considered include the tank wall vapor space, liquid-vapor interface, wetted tank wall, sludge-liquid interface, and the knuckle region.
Acceptance criteria for ultrasonic flaw indications in the inner liner of double-shell waste storage tanks
Radioactive defense waste, resulting from the chemical processing of spent nuclear fuel, has been stored in double-shell tanks (DSTS) at the Hanford Site since 1970. As part of the program to assure that the DSTs maintain their structural integrity, an inspection plan is being developed and implemented. This report provides recommendations and technical bases for acceptance criteria for flaw indications detected during ultrasonic inspection of inner liners of the DSTS. The types of indications addressed are crack-like flaws, wall thinning, and pitting. In establishing acceptable flaw sizes, the evaluations have taken into consideration the potential for crack growth by the mechanism of stress corrosion cracking. Consideration was given to technical approaches used in ASME Codes, for reactor tanks at the Department of Energy Savannah River facilities, and in recommendations by the Tank Structural Integrity Panel. The goal was to ensure that indications discovered during inspections are not large enough to ever cause a leak or rupture of the tank inner liner. The acceptance criteria are intended to be simple to apply using a set of tables giving acceptable flaw sizes. These tables are sufficiently conservative to be applicable to all double-shell tanks. In those cases that a flaw exceeds the size permitted by the tables, it is proposed that additional criteria permit more detailed and less conservative evaluations to address specific conditions of stress levels, operating temperature, flaw location, and material properties.
Acceptance of waste for disposal in the potential United States repository at Yucca Mountain, Nevada
This paper addresses the process for the acceptance of waste into the waste management system (WMS) with a focus on the detailed requirements identified from the Waste Acceptance System Requirements Document. Also described is the recent dialogue between OCRWM and the Office of Environmental Management to resolve issues, including the appropriate interpretation and application of regulatory and system requirements to DOE-owned spent fuel. Some information is provided on the design of the repository system to aid the reader in understanding how waste that is accepted into the WMS is received and emplaced in the repository.