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
Numerical analysis of thermal-hydrological conditions in thesingle heater test at Yucca Mountain (open access)

Numerical analysis of thermal-hydrological conditions in thesingle heater test at Yucca Mountain

The Single Heater Test (SHT) is one of two in-situ thermal tests included in the site characterization program for the potential underground nuclear waste repository at Yucca Mountain. The heating phase of the SHT started in August 1996, and was completed in May 1997 after 9 months of heating. The coupled processes in the unsaturated fractured rock mass around the heater were monitored by numerous sensors for thermal, hydrological, mechanical and chemical data. In addition to passive monitoring, active testing of the rock mass moisture content was performed using geophysical methods and air injection testing. The extensive data set available from this test gives a unique opportunity to improve the understanding of the thermal-hydrological situation in the natural setting of the repository rocks. The present paper focuses on the 3-D numerical simulation of the thermal-hydrological processes in the SHT using TOUGH2. In the comparative analysis, they are particularly interested in the accuracy of different fracture-matrix-interaction concepts such as the Effective Continuum (ECM), the Dual Continuum (DKM), and the Multiple Interacting Continua (MINC) method.
Date: August 8, 1998
Creator: Birkholzer, Jens T. & Tsang, Yvonne W.
Object Type: Report
System: The UNT Digital Library
Report of the CEBAF PAC4 Subcomittee on STAR (open access)

Report of the CEBAF PAC4 Subcomittee on STAR

This report discusses the following topics: the symmetric toroidal array (STAR) spectrometer facility; investigation of the N {yields} {Delta} transition; Hyperon production in the (e, e{prime}k) reactions; investigation of few-body systems with the (e, e{prime}p) reaction; nuclear structure studies with the (e,e{prime}pp) reaction; Measurement of G{sub Em} in a recoil polarimetry measurement; parity violation measurements; and STAR design and performance.
Date: August 8, 1990
Creator: Barnes, P. D.
Object Type: Report
System: The UNT Digital Library
Radiolabeled androgens and progestins as imaging agents for tumors of the prostate and breast (open access)

Radiolabeled androgens and progestins as imaging agents for tumors of the prostate and breast

We are preparing progestins and androgens, labeled with the single photon emitters technetium-99m and rhenium-186 and the positron-emitting radionuclide fluorine-18. In both cases, ligands selected have very high affinity for the respective receptor, low affinity for blood and non-specific binders and to be reasonably resistant to metabolism: The progestins will be derivatives of the potent progestins ORG2058, norgestrel, RU486, and an unusual retroprogestin and the androgens will be derivatives of the high affinity analogs of natural and synthetic androgens. Radiometal labeling will involve carefully designed steroid conjugates with N[sub 2]S[sub 2] or related chelates, or novel metal linkages, and metal complexes that themselves mimic a steroid. Fluorine substitution will be made at positions where bulk and polarity are tolerated and metabolic defluorination is minimal. In vitro competitive binding studies will be performed on the unlabeled analogs to determine their binding characteristics towards a series of steroid receptors and blood binding proteins, and Log P values will be estimated from BPLC. Tissue distribution studies with the radiolabeled progestins will be done in estrogen-primed rats using the uterus as a target, and with the radioandrogens in estrogen-treated rats using the prostate as a target. Ultimately, in collaborative studies, these radiopharmaceuticals are to …
Date: August 8, 1992
Creator: Katzenellenbogen, J.A.
Object Type: Report
System: The UNT Digital Library
The records management challenge (open access)

The records management challenge

None
Date: August 8, 1990
Creator: Zeile, H. J.
Object Type: Article
System: The UNT Digital Library
Texas Register, Volume 22, Number 59, Pages 7265-7427, August 8, 1997 (open access)

Texas Register, Volume 22, Number 59, Pages 7265-7427, August 8, 1997

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date: August 8, 1997
Creator: Texas. Secretary of State.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Texas Register, Volume 20, Number 59, Pages 5959-6041, August 8, 1995 (open access)

Texas Register, Volume 20, Number 59, Pages 5959-6041, August 8, 1995

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date: August 8, 1995
Creator: Texas. Secretary of State.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Texas Attorney General Opinion: JM-1204 (open access)

Texas Attorney General Opinion: JM-1204

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Jim Mattox, regarding a legal question submitted for clarification: Whether an uncompensated commissioner of a county housing authority may receive mileage credits attributable to authority travel (RQ-1979)
Date: August 8, 1990
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Realizing parallel reduction operation in Sisal 1.2. Revision 1 (open access)

Realizing parallel reduction operation in Sisal 1.2. Revision 1

Often the tasks of a parallel job compute sets of values that are reduced to a single value or gathered to build an aggregate structure. Since reductions may introduce dependencies, most languages separate computation and reduction. For example, Fortran 90 and HPF provide a rich set of predefined reduction functions but only for extant arrays. Sisal 1.2 is unique in that it supports seven reduction operations as a natural consequence of loop expressions. These reductions are limited and cannot express the variety of reduction operations found in parallel programs. In this paper, the authors present compilation techniques that recognize pairs of computation-reduction expressions in Sisal 1.2 and fuse them into single parallel loops. This optimization overlaps computation and reduction, reduces runtime overhead, and reduces storage requirements. They describe an implementation and they present performance numbers that demonstrate the utility of their techniques.
Date: August 8, 1994
Creator: Denton, S. M.; Feo, J. T. & Miller, P. J.
Object Type: Article
System: The UNT Digital Library
Demonstration of zinc/air fuel battery to enhance the range and mission of fleet electric vehicles: Preliminary results in the refueling of a multicell module (open access)

Demonstration of zinc/air fuel battery to enhance the range and mission of fleet electric vehicles: Preliminary results in the refueling of a multicell module

We report progress in an effort to develop and demonstrate a refuelable zinc/air battery for fleet electric vehicle applications. A refuelable module consisting of twelve bipolar cells with internal flow system has been refueled at rates of nearly 4 cells per minute refueling time of 10 minutes for a 15 kW, 55 kWh battery. The module is refueled by entrainment of 0.5-mm particles in rapidly flowing electrolyte, which delivers the particles into hoppers above each cell in a parallel-flow hydraulic circuit. The concept of user-recovery is presented as an alternative to centralized service infrastructure during market entry.
Date: August 8, 1994
Creator: Cooper, J. F.; Fleming, D.; Keene, L.; Maimoni, A.; Peterman, K. & Koopman, R.
Object Type: Article
System: The UNT Digital Library
Radiation transport between concentric spheres (open access)

Radiation transport between concentric spheres

This is a note originally distributed in 1983. I am re-releasing it now, with a couple of words changed, so that it can be used for test problems, distributed more openly, and so forth. One could argue that it should be published, but I do not have time to reshape it into something I would regard as suitable for journal publication. A different derivation of the same result is being published in an appendix in D.W. Phillion and S.M. Pollaine, ``Dynamical Compensation of Irradiation Nonuniformities in a Spherical Hohlraum Illuminated with Tetrahedral Symmetry by Laser Beams,`` submitted to Phys. Plasmas.
Date: August 8, 1994
Creator: Haan, S. W.
Object Type: Report
System: The UNT Digital Library
Small geothermal electric systems for remote powering (open access)

Small geothermal electric systems for remote powering

This report describes conditions and costs at which quite small (100 to 1,000 kilowatt) geothermal systems could be used for off-grid powering at remote locations. This is a first step in a larger process of determining locations and conditions at which markets for such systems could be developed. The results suggest that small geothermal systems offer substantial economic and environmental advantages for powering off-grid towns and villages. Geothermal power is most likely to be economic if the system size is 300 kW or greater, down to reservoir temperatures of 100{degree}C. For system sizes smaller than 300 kW, the economics can be favorable if the reservoir temperature is about 120{degree}C or above. Important markets include sites remote from grids in many developing and developed countries. Estimates of geothermal resources in many developing countries are shown.
Date: August 8, 1994
Creator: Entingh, Daniel J.; Easwaran, Eyob. & McLarty, Lynn
Object Type: Report
System: The UNT Digital Library
Texture Development During Equal Channel Angular Forging of BCC Metals (open access)

Texture Development During Equal Channel Angular Forging of BCC Metals

Equal channel angular forging (ECAF) has been proposed as a severe plastic deformation technique for processing metals, alloys, and composites [e.g. Segal, 1995] (Fig. 1). The technique offers two capabilities of practical interest: a high degree of strain can be introduced with no change in the cross-sectional dimensions of the work-piece, hence, even greater strains can be introduced by re-inserting the work-piece for further deformation during subsequent passes through the ECAF die. Additionally, the deformation is accomplished by simple shear (like torsion of a short tube) on a plane whose orientation, with respect to prior deformations, can be controlled by varying the processing route. There is a nomenclature that has developed in the literature for the typical processing routes: A: no rotations; B{sub A}: 90 degrees CW (clockwise), 90 degrees CCW (counterclockwise), 9O degrees CW, 90 degrees CCW...; Bc: 90 degrees CW, 90 degrees CW, 90 degrees CW...; and C: 180 degrees, 18 0 degrees.... The impact of processing route on the subsequent microstructure [Ferasse, Segal, Hartwig and Goforth, 1997; Iwahashi, Horita, Nemoto and Langdon, 1996] and texture [Gibbs, Hartwig, Cornwell, Goforth and Payzant, 1998] has been the subject of numerous experimental studies.
Date: August 8, 1999
Creator: Agnew, S. R.
Object Type: Article
System: The UNT Digital Library
Direct aromatization of methane. Quarterly technical progress report No. 10, January 1, 1995--March 31, 1995 (open access)

Direct aromatization of methane. Quarterly technical progress report No. 10, January 1, 1995--March 31, 1995

Further investigations of assisted pyrolysis by the addition of ethane as a free-radical initiator were carried out during this reporting period. The effects of temperature, space velocity, and ethane/methane ratio, in the presence of quench water, have been addressed. As expected, reaction quenching resulted in lower conversions than without quenching, but also in significantly lower yields of {open_quotes}tar-like{close_quotes} products. High C{sub 2}/C{sub 1} ratios and low space velocities result in significant increases in the {open_quotes}tar-like{close_quotes} product yields. Very low ethane concentrations were required to initiate methane pyrolysis at lower temperatures without a major negative effect on product selectivities.
Date: August 8, 1995
Creator: unknown
Object Type: Report
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
Radiolabeled androgens and progestins as imaging agents for tumors of the prostate and breast. Technical progress report, February 1, 1992--January 31, 1993 (open access)

Radiolabeled androgens and progestins as imaging agents for tumors of the prostate and breast. Technical progress report, February 1, 1992--January 31, 1993

We are preparing progestins and androgens, labeled with the single photon emitters technetium-99m and rhenium-186 and the positron-emitting radionuclide fluorine-18. In both cases, ligands selected have very high affinity for the respective receptor, low affinity for blood and non-specific binders and to be reasonably resistant to metabolism: The progestins will be derivatives of the potent progestins ORG2058, norgestrel, RU486, and an unusual retroprogestin and the androgens will be derivatives of the high affinity analogs of natural and synthetic androgens. Radiometal labeling will involve carefully designed steroid conjugates with N{sub 2}S{sub 2} or related chelates, or novel metal linkages, and metal complexes that themselves mimic a steroid. Fluorine substitution will be made at positions where bulk and polarity are tolerated and metabolic defluorination is minimal. In vitro competitive binding studies will be performed on the unlabeled analogs to determine their binding characteristics towards a series of steroid receptors and blood binding proteins, and Log P values will be estimated from BPLC. Tissue distribution studies with the radiolabeled progestins will be done in estrogen-primed rats using the uterus as a target, and with the radioandrogens in estrogen-treated rats using the prostate as a target. Ultimately, in collaborative studies, these radiopharmaceuticals are to …
Date: August 8, 1992
Creator: Katzenellenbogen, J. A.
Object Type: Report
System: The UNT Digital Library
Combustion and fuel loading characteristics of Hanford Site transuranic solid waste (open access)

Combustion and fuel loading characteristics of Hanford Site transuranic solid waste

The Waste Receiving and Processing (WRAP) Facility is being designed for construction in the north end of the Central Waste Complex. The WRAP Facility will receive, store, and process radioactive solid waste of both transuranic (TRU) and mixed waste (mixed radioactive-chemical waste) categories. Most of the waste is in 208-L (55-gal) steel drums. Other containers such as wood and steel boxes, and various sized drums will also be processed in the facility. The largest volume of waste and the type addressed in this report is TRU in 208-L (55-gal) drums that is scheduled to be processed in the Waste Receiving and Processing Facility Module 1 (WRAP 1). Half of the TRU waste processed by WRAP 1 is expected to be retrieved stored waste and the other half newly generated waste. Both the stored and new waste will be processed to certify it for permanent storage in the Waste Isolation Pilot Plant (WIPP) or disposal. The stored waste will go through a process of retrieval, examination, analysis, segregation, repackaging, relabeling, and documentation before certification and WIPP shipment. Newly generated waste should be much easier to process and certify. However, a substantial number of drums of both retrievable and newly generated waste …
Date: August 8, 1994
Creator: Greenhalgh, W. O.
Object Type: Report
System: The UNT Digital Library
Surface Inspection using fourier transform infrared spectroscopy (open access)

Surface Inspection using fourier transform infrared spectroscopy

The use of reflectance Fourier transform infrared (FTIR) spectroscopy as a tool for surface inspection is described. Laboratory instruments and portable instruments can support remote sensing probes that can map chemical contaminants on surfaces. Detection limits under the best of conditions are in the subnanometer range (i.e., near absolute cleanliness), excellent performance is obtained in the submicrometer range, and useful performance may exist for films tens of microns thick. Identifying and quantifying contamination such as mineral oils and greases, vegetable oils, and silicone oils on aluminum foil, galvanized sheet steel, smooth aluminum tubing, and gritblasted 7075 aluminum alloy and D6AC steel are described. The ability to map in time and space the distribution of oil stains on metals is demonstrated. Techniques for quantitatively applying oils to metals, subsequently verifying the application, and nonlinear relationships between reflectance and the quantity of oil are discussed.
Date: August 8, 1994
Creator: Powell, G. L.; Smyrl, N. R.; Williams, D. M.; Meyers, H. M. III; Barber, T. E. & Marrero-Rivera, M.
Object Type: Article
System: The UNT Digital Library
Neutron diffraction study of the magnetic ordering of BaCuO{sub 2+x} (open access)

Neutron diffraction study of the magnetic ordering of BaCuO{sub 2+x}

Neutron diffraction measurements have revealed that BaCuO{sub 2+x} orders antiferromagnetically below T{sub N} = (15.0 {+-} 0.5) with a magnetic propagating vector {kappa} = [1 1 1]. The Cu atoms in the Cu{sub 6} ring clusters, located at the (1/4, 1/4, 1/4) positions, order ferromagnetically within these clusters while the clusters themselves order antiferromagnetically. The ordered magnetic moment of each of these Cu atoms is (0.89 {+-} 0.05){mu}{sub B} at T=4.2K. No evidence of long-range magnetic ordering of the Cu atoms in the Cu{sub 18} clusters, located at the (O, O, O) and (1/2, 1/2, 1/2) positions, was found down to a temperature T=2.5K.
Date: August 8, 1994
Creator: Wang, X. L.; Fernandez-Baca, J. A.; Wang, Z. R.; Vaknin, D. & Johnston, D. C.
Object Type: Article
System: The UNT Digital Library
Properties of jets in Z events from 1.8 TeV {bar p}p collisions (open access)

Properties of jets in Z events from 1.8 TeV {bar p}p collisions

We have studied the properties of Z boson events produced in 1.8 TeV p{bar p} collisions using 19.3 pb{sup {minus}1} of integrated luminosity collected by the Collider Detector at Fermilab (CDF) during the 1992--1993 Tevatron run. We compare the characteristics of the hadronic jets associated with the Z to leading-order QCD calculations using the VECBOS Monte Carlo program. For a subsample of events, we identify B jets and compare their rates to those expected from events with generic QCD jets.
Date: August 8, 1994
Creator: Hauger, S. A.
Object Type: Article
System: The UNT Digital Library
Computational model of drilling with high radiance pulsed lasers (open access)

Computational model of drilling with high radiance pulsed lasers

This paper describes a model of drilling by high radiance pulsed lasers. The model contains a one-dimensional description of heat transport below the bottom of the hole, hydrodynamic expansion of the vapor and compressed air, and light propagation through the vapor. The pressure and energy of the vapor are taken from a separate Saha equilibrium code. The boundary conditions at the vaporization surface include the formation of a Knudsen layer within which macroscopic fluid conditions are reached. The absorption mechanisms in the pertinent range of densities and temperatures are photoionization and inverse bremsstrahlung. The model has been applied to the case of drilling in stainless steel with green copper laser light, for peak input intensities ranging from 10{sup 8} to 5 {times} 10{sup 10} W/cm{sup 2}. Below 3 {times} 10{sup 8} W/cm{sup 2}, their is negligible absorption in the vapor and ablation increases rapidly with intensity. Above this point, ablation still generally increases with intensity, because of a combination of partially penetrating light and electron thermal conduction to the surface. The predicted ablation rates agree semiquantitatively with experiment.
Date: August 8, 1994
Creator: Boley, C. D.
Object Type: Article
System: The UNT Digital Library
High speed optical links between LLNL and Berkeley (open access)

High speed optical links between LLNL and Berkeley

The Advanced Telecommunications Program at Lawrence Livermore National Laboratory, in collaboration with Pacific Bell, is developing an experimental high speed, four wavelength, protocol independent optical link for evaluating wide area networking interconnection schemes and the use of fiber amplifiers. Lawrence Livermore National Laboratory, as a super-user, supercomputer, and super-application site, is anticipating the future bandwidth and protocol requirements to connect to other such sites as well as to connect to remote sited control centers and experiments. In this paper we discuss our vision of the future of Wide Area Networking and describe the plans for the wavelength division multiplexed link between Livermore and the University of California at Berkeley.
Date: August 8, 1994
Creator: Lennon, W. J. & Thombley, R. L.
Object Type: Article
System: The UNT Digital Library
The physics design of the Tokamak Physics Experiment (open access)

The physics design of the Tokamak Physics Experiment

The physics approaches to improved, steady-state tokamak reactors, as evolved through reactor design studies, ideas based on experimental results, and better theoretical understanding, are the foundation for the mission and physics design of the Tokamak Physics Experiment (TPX). The mission of TPX is to develop the scientific basis for cost-competitive, continuously operating tokamak power plants. We report here the design status of TPX, a device optimized to achieve improved performance through strong plasma shaping, recycling control, and current profile shaping, while operating continuously. The design incorporates poloidal field flexibility for a wide range of operation in normalized beta and internal inductance, a double-null ``Vee`` divertor configuration for power and particle control, internal and external n {ne} 0 coils, as well as passive stabilizers, for control of MHD activity, and remote maintenance for continuous high-power operation in deuterium. Having superconducting poloidal and toroidal coils, the TPX device itself is capable of continuous operation, although initially auxiliary equipment limits the pulse length to 1000 sec.
Date: August 8, 1994
Creator: Thomassen, K. I.; Batchelor, D. B. & Bialek, J.
Object Type: Article
System: The UNT Digital Library
Visualizing 3D velocity fields near contour surfaces. Revision 1 (open access)

Visualizing 3D velocity fields near contour surfaces. Revision 1

Vector field rendering is difficult in 3D because the vector icons overlap and hide each other. We propose four different techniques for visualizing vector fields only near surfaces. The first uses motion blurred particles in a thickened region around the surface. The second uses a voxel grid to contain integral curves of the vector field. The third uses many antialiased lines through the surface, and the fourth uses hairs sprouting from the surface and then bending in the direction of the vector field. All the methods use the graphics pipeline, allowing real time rotation and interaction, and the first two methods can animate the texture to move in the flow determined by the velocity field.
Date: August 8, 1994
Creator: Max, N.; Crawfis, R. & Grant, C.
Object Type: Article
System: The UNT Digital Library