Radiation-driven evolution of low-mass x-ray binaries and the formation of millisecond pulsars (open access)

Radiation-driven evolution of low-mass x-ray binaries and the formation of millisecond pulsars

Recent data on low-mass X-ray binaries (LMXBs) and millisecond pulsars (MSPs) pose a challenge to evolutionary theories which neglect the effects of disk and comparison irradiation. Here we discuss the main features of a radiation-driven (RD) evolutionary model that may be applicable to several LMXBs. According to this model, radiation from the accreting compact star in LMXBs vaporizes'' the accretion disk and the companion star by driving a self-sustained mass loss until a sudden accretion-turn off occurs. The main characteristics of the RD-evolution are: (1) lifetime of RD-LMXB's is of order 10{sup 7} years or less; (2) both the orbital period gap and the X-ray luminosity may be consequences of RD-evolution of LMXB's containing lower main sequence and degeneration companion stars; (3) the companion star may transfer mass to the primary even if it underfills its Roche lobe; (4) a class of recycled MSPs can continue to vaporize the low-mass companions by a strong pulsar wind even after the accretion turn-off; (5) the RD-evolutionary model resolves the apparent statistical descrepancy between the number of MSPs and their LMXB progenitors in the Galaxy. We discuss the implications of the discovery of single MSPs in low-density globular clusters and the recent measurements …
Date: August 8, 1991
Creator: Tavani, M. (Lawrence Livermore National Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Astronomy)
Object Type: Article
System: The UNT Digital Library
Application of telerobotic control to remote processing of nuclear material (open access)

Application of telerobotic control to remote processing of nuclear material

In processing radioactive material there are certain steps which have customarily required operators working at glove box enclosures. This can subject the operators to low level radiation dosages and the risk of accidental contamination, as well as generate significant radioactive waste to accommodate the human interaction. An automated system is being developed to replace the operator at the glove box and thus remove the human from these risks, and minimize waste. Although most of the processing can be automated with very little human operator interaction, there are some tasks where intelligent intervention is necessary to adapt to unexpected circumstances and events. These activities will require that the operator be able to interact with the process using a remote manipulator in a manner as natural as if the operator were actually in the work cell. This robot-based remote manipulation system, or telerobot, must provide the operator with an effective means of controlling the robot arm, gripper and tools. This paper describes the effort in progress in Lawrence Livermore National Laboratory to achieve this capability. 8 refs.
Date: July 8, 1991
Creator: Merrill, R. D.; Grasz, E. L.; Herget, C. J.; Gavel, D. T.; Addis, R. B. & DeMinico, G. A.
Object Type: Article
System: The UNT Digital Library
Interface stability and defect formation during crystal growth (open access)

Interface stability and defect formation during crystal growth

Unidirectional solidification experiments have been carried out in organic crystals with the aim of improving our knowledge on the effects of constraints on the interface morphology and to increase our understanding of the growth of anisotropic materials. The experimental information shows that lateral constraints such as a sharp change in the cross-sectional area in the solid liquid interface path, can produce important changes in the microstructure if the interface morphology is planar, cellular or dendritic. The study of anisotropic materials cover several topics. It is first shown that slight anisotropy does not influence the dendrite tip selection criterion. This conclusion is obtained from the analysis of the relationship between tip radius and velocity for dendrites growing under the steady state condition for two different materials, CBr{sub 4} and C{sub 2}Cl{sub 6}, which have different surface energy anisotropy values. The values of the dendrite operating parameters {sigma}* are compared with the predictions of the solvability theory and the morphological stability theory. The experiments show better agreement with the latter theory. Critical experiments have been designed and carried out to find the response functions which determine the composition and temperature of the interface as a function of velocity in faceted materials. The …
Date: January 8, 1991
Creator: Fabietti, L.M.R.
Object Type: Report
System: The UNT Digital Library
Editing graphs for maximum effect (open access)

Editing graphs for maximum effect

The paper contains over eighty rules for editing graphs, arranged under nine major headings in a logical sequence for editing all the graphs in a manuscript. It is excerpted from a monograph used at the Lawrence Livermore National Laboratory to train beginning technical editors in editing graphs; a corresponding Hypercard stack is also used in this training. 6 refs., 4 figs.
Date: January 8, 1991
Creator: Murphy, P. W. & Rhiner, R. W.
Object Type: Article
System: The UNT Digital Library
Gas-phase generations and rearrangement of silathiones, R sub 2 Si=S (open access)

Gas-phase generations and rearrangement of silathiones, R sub 2 Si=S

Three routes are explored for the generation of silathiones: (1) the retroene elimination of propene from allythiodimethylsilane and 1-allythio-1-hydrido-1,2,2,2-tetramethylsilane; (2) the reaction of silylene, Me{sub 2}Di, with carbon disulfide which is thought to form a transient 3-membered ring with CS{sub 2} and the elimination of carbon disulfide to produce diethylsilathione; and (3) the beta-elimination of bis(trimethylsilythio)dimethylsilane. All these methods are explored in some detail. A second example of a silathione-silylene isomerization was observed in the pyrolysis of 1,1-bis(trimethylsilythio)-1,2,2,2-tetramethyldisilane. 89 refs., 5 figs., 10 tab. (BM)
Date: January 8, 1991
Creator: Kim, Chong Bok.
Object Type: Report
System: The UNT Digital Library
Photomodulation spectroscopy of photocarrier dynamics, electronic defects and morphology of conducting polymers (open access)

Photomodulation spectroscopy of photocarrier dynamics, electronic defects and morphology of conducting polymers

This is a progress report on the second period of activities associated with the DOE grant to the Physics Department of the University of Utah, starting on April 1st, 1991, on photocarrier dynamics, electronic defects and morphology of conducting polymers using the photomodulation spectroscopy. During the second period of this grant we have achieved impressive results and have started new studies, to be completed during the grant continuation period of the third year. We will describe our progress according to the material studied, since this is the best method to summarize our accomplishments. We have used a variety of techniques in our studies such as: CW photomodulation, photomodulation in the femtosecond and picosecond time ranges, CW resonant Raman scattering, transient photoinduced Raman scattering, electro-absorption, degenerate four-wave mixing and the newly technique of spin dependent photomodulation. These techniques have been used to obtain the transient electronic response of the studied conducing polymers.
Date: October 8, 1991
Creator: Vardeny, Z. V.
Object Type: Report
System: The UNT Digital Library
Competing electron-electron/electron-phonon interactions and polyacetylene (open access)

Competing electron-electron/electron-phonon interactions and polyacetylene

Using Lanczos exact diagonalization, we investigate the effects of the competition between the electro-electron and electron-phonon interactions in the context of the 1-D tight-binding Peierls-Hubbard Hamiltonian, studying various structural, optical, and vibrational properties of strongly correlated systems. We use polyacetylene as our experimental guide, and perform a parameter space search to determine the level at which a unique set of parameters can model this prototypical conducting polymer and, more generally, the applicability of the simple'' 1-D Peierls-Hubbard Hamiltonian to these highly interesting materials. 9 refs., 3 tabs.
Date: April 8, 1991
Creator: Gammel, J.T. (Los Alamos National Lab., NM (USA) Bayreuth Univ. (Germany, F.R.). Physics Inst.); Campbell, D.K. (Los Alamos National Lab., NM (USA)) & Loh, E.Y. Jr. (Thinking Machines Corp., Cambridge, MA (USA))
Object Type: Article
System: The UNT Digital Library
[Assessment of effects of surfactants in a heavy oil reservoir] (open access)

[Assessment of effects of surfactants in a heavy oil reservoir]

During the past three months we have carefully negotiated a joint venture to implement a pilot for testing the two enhanced oil recovery processes developed at CLD Technology, Inc. The technical staff at CLD Technology, Inc. has decided to model the heavy oil reserve on the Cantleberry Lease, the Jasmin oil field in Kern County, California. Staff members have designed a new sand pack to represent one-eighth (1/8) of a one, ten-acre, five-spot well pattern that will represent the sands of the Cantleberry lease. All calculated parameters are listed in Table 1. The 3-dimensional scaled physical model design represents a typical Cantleberry steamflood pattern. The design of the model will allow the creation of zones identical to those in the Cantleberry lease which will represent the shale break between the Cantleberry A'' and B'' sands. The last 3-dimensional scaled physical model experiment, needed to design the pilot, is ready to go awaiting continuous funding from the DOE.
Date: April 8, 1991
Creator: Kostura, J.A.
Object Type: Report
System: The UNT Digital Library
[Assessment of effects of surfactants in a heavy oil reservoir]. Third quarterly report, March 30, 1991 (open access)

[Assessment of effects of surfactants in a heavy oil reservoir]. Third quarterly report, March 30, 1991

During the past three months we have carefully negotiated a joint venture to implement a pilot for testing the two enhanced oil recovery processes developed at CLD Technology, Inc. The technical staff at CLD Technology, Inc. has decided to model the heavy oil reserve on the Cantleberry Lease, the Jasmin oil field in Kern County, California. Staff members have designed a new sand pack to represent one-eighth (1/8) of a one, ten-acre, five-spot well pattern that will represent the sands of the Cantleberry lease. All calculated parameters are listed in Table 1. The 3-dimensional scaled physical model design represents a typical Cantleberry steamflood pattern. The design of the model will allow the creation of zones identical to those in the Cantleberry lease which will represent the shale break between the Cantleberry ``A`` and ``B`` sands. The last 3-dimensional scaled physical model experiment, needed to design the pilot, is ready to go awaiting continuous funding from the DOE.
Date: April 8, 1991
Creator: Kostura, J. A.
Object Type: Report
System: The UNT Digital Library
False color viewing device (open access)

False color viewing device

This invention consists of a viewing device for observing objects in near-infrared false-color comprising a pair of goggles with one or more filters in the apertures, and pads that engage the face for blocking stray light from the sides so that all light reaching, the user`s eyes come through the filters. The filters attenuate most visible light and pass near-infrared (having wavelengths longer than approximately 700 nm) and a small amount of blue-green and blue-violet (having wavelengths in the 500 to 520 nm and shorter than 435 nm, respectively). The goggles are useful for looking at vegetation to identify different species and for determining the health of the vegetation, and to detect some forms of camouflage.
Date: May 8, 1991
Creator: Kronberg, J. W.
Object Type: Patent
System: The UNT Digital Library
Laser cutting with chemical reaction assist (open access)

Laser cutting with chemical reaction assist

This invention is comprised of a method for cutting with a laser beam where an oxygen-hydrocarbon reaction is used to provide auxiliary energy to a metal workpiece to supplement the energy supplied by the laser. Oxygen is supplied to the laser focus point on the workpiece by a nozzle through which the laser beam also passes. A liquid hydrocarbon is supplied by coating the workpiece along the cutting path with the hydrocarbon prior to laser irradiation or by spraying a stream of hydrocarbon through a nozzle aimed at a point on the cutting path which is just ahead of the focus point during irradiation.
Date: April 8, 1991
Creator: Gettemy, D. J.
Object Type: Patent
System: The UNT Digital Library
D-Zero Collider Detector CC Initial Vacuum Pumping Preparation and Procedure (open access)

D-Zero Collider Detector CC Initial Vacuum Pumping Preparation and Procedure

The initial vacuum pumping of the fully loaded cryostats immediately upon completing the minimum head welding necessary for the cryostat vacuum loading is important to (1) water removal, (2) high vapor pressure (micron level) outgassing, (3) helium mass spectrometer leak checking sensitivity, and (4) a less well understood concern for LAr background contamination. The CC pumping preparation and procedure that has been utilized is recorded here. Recommendations are incorporated in italics and in context to improve the EC vacuum preparations and pumping performance. The estimated pumping loads of large assemblies of (G10) water laden modules are calculated in EN 270. The predicted and experienced water pumping period was ca. 45 days. The cryopump specifically designed to serve this purpose is described in EN 291. These notes are recommended background reading for this work.
Date: April 8, 1991
Creator: Wu, J.
Object Type: Report
System: The UNT Digital Library
Cooler and particulate separator for an off-gas stack (open access)

Cooler and particulate separator for an off-gas stack

This report describes an off-gas stack for a melter, furnace or reaction vessel comprising an air conduit leading to two sets of holes, one set injecting air into the off-gas stack near the melter plenum and the second set injecting air downstream of the first set. The first set injects air at a compound angle, having both downward and tangential components, to create a reverse vortex flow, counter to the direction of flow of gas through the stack and also along the periphery of the stack interior surface. Air from the first set of holes prevents recirculation zones from forming and the attendant accumulation of particulate deposits on the wall of the stack and will also return to the plenum any particulate swept up in the gas entering the stack. The second set of holes injects air in the same direction as the gas in the stack to compensate for the pressure drop and to prevent the concentration of condensate in the stack. A set of sprayers, receiving water from a second conduit, is located downstream of the second set of holes and sprays water into the gas to further cool it.
Date: April 8, 1991
Creator: Wright, G. T.
Object Type: Patent
System: The UNT Digital Library
Atomic line emission analyzer for hydrogen isotopes (open access)

Atomic line emission analyzer for hydrogen isotopes

Apparatus for isotopic analysis of hydrogen comprises a low pressure chamber into which a sample of hydrogen is introduced and then exposed to an electrical discharge to excite the electrons of the hydrogen atoms to higher energy states and thereby cause the emission of light on the return to lower energy states, a Fresnel prism made at least in part of a material anomalously dispersive to the wavelengths of interest for dispersing the emitted light, and a photodiode array for receiving the dispersed light. The light emitted by the sample is filtered to pass only the desired wavelengths, such as one of the lines of the Balmer series for hydrogen, the wavelengths of which differ slightly from one isotope to another. The output of the photodiode array is processed to determine the relative amounts of each isotope present in the sample. Additionally, the sample itself may be recovered using, a metal hydride.
Date: May 8, 1991
Creator: Kronberg, James W.
Object Type: Patent
System: The UNT Digital Library
Elimination of ``memory`` from sample handling and inlet system of a mass spectrometer (open access)

Elimination of ``memory`` from sample handling and inlet system of a mass spectrometer

This paper describes a method for preparing the sample handling and inlet system of a mass spectrometer for analysis of a subsequent sample following analysis of a previous sample comprising the flushing of the system interior with supercritical CO{sub 2} and venting the interior. The method eliminates the effect of system ``memory`` on the subsequent analysis, especially following persistent samples such as xenon and krypton.
Date: May 8, 1991
Creator: Chastgner, P.
Object Type: Patent
System: The UNT Digital Library
Manufacture of silicon carbide using solar energy (open access)

Manufacture of silicon carbide using solar energy

This invention is comprised of a method is described for producing silicon carbide particles using solar energy. The method is efficient and avoids the need for use of electrical energy to heat the reactants. Finely divided silica and carbon are admixed and placed in a solar-heated reaction chamber for a time sufficient to cause a reaction between the ingredients to form silicon carbide of very small particle size. No grinding of silicon carbide is required to obtain small particles. The method may be carried out as a batch process or as a continuous process.
Date: April 8, 1991
Creator: Glatzmaier, G. C.
Object Type: Patent
System: The UNT Digital Library
Reversibly immobilized biological materials in monolayer films on electrodes (open access)

Reversibly immobilized biological materials in monolayer films on electrodes

A method is provided for reversibly binding charged biological particles in a fluid medium to an electrode surface. The method comprises treating (e.g., derivatizing) the electrode surface with an electrochemically active material; connecting the electrode to an electrical potential; and exposing the fluid medium to the electrode surface in a manner such that the charged particles become adsorbed on the electrode surface.
Date: April 8, 1991
Creator: Weaver, P. F. & Frank, A. J.
Object Type: Patent
System: The UNT Digital Library
Vaporizing neutron stars in low-mass x-ray binaries and the statistics of millisecond pulsars (open access)

Vaporizing neutron stars in low-mass x-ray binaries and the statistics of millisecond pulsars

Recent data on low-mass X-ray binaries (LMXBs) and msec pulsars (MSPs) pose a challenge to evolutionary which neglect the effects of disk and companion irradiation. Here we discuss the main features of a radiation-driven (RD) evolutionary model that may be applicable to several LMXBs. According to this model, irradiation from the accreting compact star LMXBs vaporizes'' the accretion disk and the companion star by driving a self-sustained mass loss until a sudden accretion-turn of occurs. The main characteristics of the RD-evolution are: (1) the lifetime of RD-LMXB's is of order 10{sup 7} years or less: (2) both the orbital period gap and the X-ray luminosity may be consequences of RD-evolution of LMXB's containing lower main sequence and degenerate companion stars; (3) the companion star may transfer mass to the primary even if it underfills its Roche lobe; (4) the recycled msec pulsar can continue to vaporize the low-mass companion star even after the accretion turn-off produced by a strong pulsar wind; (5) the RD-evolutionary model resolves the apparent statistical discrepancy between the number of MSP's and their LMXB progenitors. 14 refs., 1 fig., 1 tab.
Date: August 8, 1991
Creator: Tavani, M. (California Univ., Livermore, CA (United States). Inst. of Geophysics and Planetary Physics)
Object Type: Article
System: The UNT Digital Library
(Contaminated soil) (open access)

(Contaminated soil)

The traveler attended the Third International Conference on Contaminated Soil, held in Karlsruhe, Germany. The Conference was a status conference for worldwide research and practice in contaminated soil assessment and environmental restoration, with more than 1500 attendees representing over 26 countries. The traveler made an oral presentation and presented a poster. At the Federal Institute for Water, Soil and Air Hygiene, the traveler met with Dr. Z. Filip, Director and Professor, and Dr. R. Smed-Hildmann, Research Scientist. Detailed discussions were held regarding the results and conclusions of a collaborative experiment concerning humic substance formation in waste-amended soils.
Date: January 8, 1991
Creator: Siegrist, Robert L.
Object Type: Report
System: The UNT Digital Library
Design of slurry reactor for indirect liquefaction applications. Quarterly technical progress report, January 1991--March 1991 (open access)

Design of slurry reactor for indirect liquefaction applications. Quarterly technical progress report, January 1991--March 1991

The objective of this project is to design a conceptual slurry reactor for two indirect liquefaction applications; production of methanol and production of hydrogen fuels via Fischer-Tropsch route. The work will be accomplished by the formulation of reactor models for both the processes and use computer simulation. Process data, kinetic and thermodynamic data, heat and mass transfer data and hydrodynamic data will be used in the mathematical models to describe the slurry reactor for each of the two processes. The cost of current vapor phase reactor systems will be compared with cost estimated for the slurry reactor systems. For the vapor phase systems, upstream and downstream processing equipments may have to be included during cost analysis for a meaningful cost comparison.
Date: April 8, 1991
Creator: Prakash, A. & Bendale, P. G.
Object Type: Report
System: The UNT Digital Library
Photomodulation spectroscopy of photocarrier dynamics, electronic defects and morphology of conducting polymers. Progress report (open access)

Photomodulation spectroscopy of photocarrier dynamics, electronic defects and morphology of conducting polymers. Progress report

This is a progress report on the second period of activities associated with the DOE grant to the Physics Department of the University of Utah, starting on April 1st, 1991, on photocarrier dynamics, electronic defects and morphology of conducting polymers using the photomodulation spectroscopy. During the second period of this grant we have achieved impressive results and have started new studies, to be completed during the grant continuation period of the third year. We will describe our progress according to the material studied, since this is the best method to summarize our accomplishments. We have used a variety of techniques in our studies such as: CW photomodulation, photomodulation in the femtosecond and picosecond time ranges, CW resonant Raman scattering, transient photoinduced Raman scattering, electro-absorption, degenerate four-wave mixing and the newly technique of spin dependent photomodulation. These techniques have been used to obtain the transient electronic response of the studied conducing polymers.
Date: October 8, 1991
Creator: Vardeny, Z. V.
Object Type: Report
System: The UNT Digital Library
D0 Collider Detector LINDE, East Chicago (LAr Contractor) Trip Report (open access)

D0 Collider Detector LINDE, East Chicago (LAr Contractor) Trip Report

East Chicago is capable of processing air at a 6-7E6 SCFH rate. They can produce as much as 1.2E6 SCFH 02 and 4.5 SCFH N2 (not coincidently) with a peak product efficiency of 85-86% (product to total Intake). The general area demand has been as high as 10E6, as low as 4.5E6, and is currently 8E6 SCFH totaI product. The plant is really four plants in one. At anyone time one or more plants can be down for maintenance and the others online and delivering to the pipe line that distributes their product to nearby steel plants, and to the liquid reservoirs (perlite insulated tanks) of 160, 160 and 200 E6 SCF. At the time of our visit two plants were down and two were on line. The following describes the characteristics of one of the four plants. The cycle requires a base compressor (Brown Boveri, 22,600 hp) that pumps to 90-100 psig, and a booster compressor (Clark, 14,000 hp) that pumps to 300 psig. Filter houses (ca. 20-ft x 20-ft) feed the suctions and the discharge is scrubbed by dual, molecular sieve, beds 0 300 psi (6-8 hour cycle time). The beds are provided with dust blow down and …
Date: February 8, 1991
Creator: Dixon, K.; Krempetz, K.; Mulholland, G.T.; Urbin, J. & /Fermilab
Object Type: Report
System: The UNT Digital Library
Finite. beta. and nonlocal calculation of collisionless and dissipative drift instabilities (open access)

Finite. beta. and nonlocal calculation of collisionless and dissipative drift instabilities

Collisionless and dissipative drift waves, driven by gradients in the plasma density and/or temperatures, are believed to dominate or at least influence the transport properties of a variety of plasma confinement devices. In a study begun in reference to transport in the Field Reversed Configuration (FRC), we have developed a theory of these waves in a high {beta} plasma, including the effect of perturbed flow in the direction of the plasma density. This study was a natural extension of previous calculations; the {beta} = 1 nature of the FRC makes a proper treatment of high {beta} effects vital to an understanding of that device. In the course of this study we have obtained a comprehensive dispersion relation which shows clearly how the numerical dissipative drift wave instabilities evolve in wavenumber as {beta} increases. A major finding from this is that the effect of finite {beta} begins to dominate long before {beta} {yields} 1; the expansion parameter is {beta}f(k, a{sub i}, K, {omega}, L{sub n}) where f can be substantially greater than 1, depending on the wavenumber of the wave parallel to the magnetic field (K), the wavenumber parallel to the particle drifts (k), the wave frequency ({omega}), the strength of …
Date: April 8, 1991
Creator: Krall, Nicholas A.
Object Type: Report
System: The UNT Digital Library
MCNP neutron benchmarks (open access)

MCNP neutron benchmarks

Over 50 neutron benchmark calculations have recently been completed as part of an ongoing program to validate the MCNP Monte Carlo radiation transport code. The new and significant aspects of this work are as follows: These calculations are the first attempt at a validation program for MCNP and the first official benchmarking of version 4 of the code. We believe the chosen set of benchmarks is a comprehensive set that may be useful for benchmarking other radiation transport codes and data libraries. These calculations provide insight into how well neutron transport calculations can be expected to model a wide variety of problems.
Date: October 8, 1991
Creator: Hendricks, John S.; Whalen, Daniel J.; Cardon, David A. & Uhle, Jennifer L.
Object Type: Article
System: The UNT Digital Library