Soft x-ray detection with diamond photoconductive detectors (open access)

Soft x-ray detection with diamond photoconductive detectors

Photoconductive detectors fabricated from natural lla diamonds have been used to measure the x-ray power emitted from laser produced plasmas. The detector was operated without any absorbing filters to distort the x-ray power measurement. The 5.5 eV bandgap of the detector material practically eliminates its sensitivity to scattered laser radiation thus permitting filterless operation. The detector response time or carrier life time was 90 ps. Excellent agreement was achieved between a diamond PCD and a multichannel photoemissive diode array in the measurement of radiated x-ray power and energy. 4 figs.
Date: May 4, 1990
Creator: Kania, D. R.; Pan, L.; Kornblum, H.; Bell, P.; Landen, O. N. & Pianetta, P.
Object Type: Article
System: The UNT Digital Library
Sitewide Environmental Assessment for the National Renewable Energy Laboratory, Golden, Colorado (open access)

Sitewide Environmental Assessment for the National Renewable Energy Laboratory, Golden, Colorado

The Solar Energy Research, Development, and Demonstration Act of 1974 authorized a federal program to develop solar energy as a viable source of the nation`s future energy needs. Under this authority, the National Renewable Energy Laboratory (NREL) was created as a laboratory of the Department of Energy (DOE) to research a number of renewable energy possibilities. The laboratory conducts its operations both in government-owned facilities on the NREL South Table Mountain (STM) Site near Golden, Colorado, and in a number of leased facilities, particularly the Denver West Office Park. NREL operations include research in energy technologies, and other areas of national environmental and energy technology interest. Examples of these technologies include electricity from sunlight with solar cells (photovoltaics); energy from wind (windmills or wind turbines); conversion of plants and plant products (biomass) into liquid fuels (ethanol and methanol); heat from the sun (solar thermal) in place of wood, oil, gas, coal and other forms of heating; and solar buildings. NREL proposes to continue and expand the present R&D efforts in C&R energy by making infrastructure improvements and constructing facilities to eventually consolidate the R&D and associated support activities at its STM Site. In addition, it is proposed that operations continue …
Date: May 4, 1993
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Radioactive Contamination in Liquid Waste Discharged to Ground at the Separations Facilities Through December, 1964 (open access)

Radioactive Contamination in Liquid Waste Discharged to Ground at the Separations Facilities Through December, 1964

This document summarizes the amounts of radioactive contamination discharged to ground from chemical separations and laboratory facilities through December, 1964. Detailed data for individual disposal sites are presented on a month-to-month basis for the period of January through December, 1964. Previous publications of this series are listed in the bibliography and may be referred to for specific information on measurements and radioactivity totals prior to December, 1964. Several changes in crib nomenclature were made during 1964. These changes are noted on the individual tables so reference may be made to them in previous reports. Tables I and II list the major disposal sites in the separation facilities, total volume of waste discharged to each location, and the gross amounts of plutonium and beta particle emitters discharged to ground since startup. Tables III through XXIV present this same data on a monthly basis for cribs still in use, and also include information on the source of the waste stream and the settling facility if used. Isotopic data are included for disposal sites from which the waste was analyzed for specific contaminants. Estimates of contamination and volumes discharged to swamps are also included in Tables XXV and XXVI.
Date: May 4, 1965
Creator: Wilson, R. H.
Object Type: Report
System: The UNT Digital Library
NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, December 15, 1991--March 15, 1992 (open access)

NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, December 15, 1991--March 15, 1992

During this period, we focused our attention in analyzing the magnetic nature of the extensively used trimetallic catalyst system Cu-Co-Cr for the production of higher alcohols. We believe that there could be some correspondence between the catalytic and magnetic behaviors of the transition metal catalyst systems. Both the morphology and metallic charge distribution of the particles are known to govern the catalytic as well as the magnetic properties of the system.
Date: May 4, 1992
Creator: Murty, A. N.
Object Type: Report
System: The UNT Digital Library
Environmental Hazards Assessment Program. Quarterly report, January 1994--March 1994 (open access)

Environmental Hazards Assessment Program. Quarterly report, January 1994--March 1994

The objectives of the EHAP program are to: Develop a holistic, national basis for risk assessment, risk management and risk communication; Develop a pool of talented scientists and experts in cleanup activities, especially in human health aspects, and; Identify needs and develop programs addressing the critical shortage of well-educated, highly-skilled technical and scientific personnel to address the health oriented aspects of environmental restoration and waste management. This report describes activities and reports on progress for the third quarter of year two (January-March, 1994) of the grant. To better accomplish objectives, grant efforts are organized into three major elements: The Crossroads of Humanity Series; Research, Science and Education Programs; and Program Management. The Crossroads of Humanity Series charted a new course, incorporating lessons learned during previous quarters into a series of programs designed to address environmental issues in a real world setting. Reports are included on the various research programs with milestones and deliverables from the third quarter.
Date: May 4, 1994
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Fundamental studies of coal liquefaction. Quarterly report No. 6, January 1--April 1, 1993 (open access)

Fundamental studies of coal liquefaction. Quarterly report No. 6, January 1--April 1, 1993

Figures 3, 4, and 5 display images of two adjacent particles chosen for analysis with characteristic dimensions of 50--100 {mu}m Figure 3 shows that there is essentially no change up to 395{degrees}C over an 18 min period, but at that point the particle labeled a begins to shrink. The action continues in Figure 4 where the particle contracts to about half its initial size over a 45 sec period as the temperature, increases from 424{degrees}C to 430{degrees}C, at which point the contraction stops. The size profile for a is presented in Figure 6 and compares very well with the profile generated in an earlier experiment from our last report. As just noted, this agreement suggests that this behavior is representative of at least one class of particle in the sample. Figure 5 shows that there is a second, higher temperature range of activity, represented by the changes in particle b. This particle contracts to about half its size from 450{degrees} to 460{degrees}C over 1 min. The temperature was held at 460{degrees} and there appears to be an additional 7--10% contraction over 10 min at that temperature, although the scatter seen in Figure 6 shows that change is not outside our …
Date: May 4, 1993
Creator: Ross, D. S.
Object Type: Report
System: The UNT Digital Library
The liquid helium thermosyphon for the GEM detector magnet (open access)

The liquid helium thermosyphon for the GEM detector magnet

The GEM detector magnet, a horizontal solenoid 19.5 m in diameter and wound with a niobium-titanium cable in conduit, will be located with it`s axis 19.5 m below grade. The conductor is wound on the inside of an aluminum bobbin which is cooled by liquid helium which flows by natural convection in a thermosyphon loop from a large storage dewar located at the ground surface. The function of the thermosyphon system is to absorb the environmental heat load as well as any internally generated heat. In the first category is included that heat which is transfered to the magnet by way of the mechanical supports, the insulation and the current leads. The internally generated heat includes the resistive heating within the normally conducting conductor splices and the inductive heating of the bobbin during current transients. Though similar systems have been employed elsewhere, there are some unique aspects to the present design. By taking advantage of the large vertical head available, the parallel heat exchanger passes within the magnet remain sub-cooled, thus insuring single phase coolant within the magnet. It is believed that this will be the first instance of such a large vertical head being used to this advantage in …
Date: May 4, 1993
Creator: Warren, R. P.
Object Type: Article
System: The UNT Digital Library
Crystalline beams: The vertical zigzag (open access)

Crystalline beams: The vertical zigzag

This note is the continuation of our comprehensive investigation of Crystalline Beams. After having determined the equations of motion and the conditions for the formation of the simplest configuration, i.e. the string, we study the possibility of storing an intense beam of charged particles in a storage ring where they form a vertical zigzag. We define the equilibrium configuration, and examine the confinement conditions. Subsequently, we derive the transfer matrix for motion through various elements of the storage ring. Finally we investigate the stability conditions for such a beam.
Date: May 4, 1994
Creator: Haffmans, A. F.; Maletic, D. & Ruggiero, A. G.
Object Type: Report
System: The UNT Digital Library
Identification of Process Hazards and Accident Scenarios for Site 300 B-Division Firing Areas, Lawrence Livermore National Laboratory (open access)

Identification of Process Hazards and Accident Scenarios for Site 300 B-Division Firing Areas, Lawrence Livermore National Laboratory

This report describes a hazard and accident analysis conducted for Site 300 operations to support update of the ''Site 300 B-Division Firing Areas Safety Analysis Report'' (SAR) [LLNL 1997]. A significant change since the previous SAR is the construction and the new Contained Firing Facility (CFF). Therefore, this hazard and accident analysis focused on the hazards associated with bunker operations to ensure that the hazards at CFF are properly characterized in the updated SAR. Hazard tables were created to cover both the CFF and the existing bunkers with ''open air'' firing tables.
Date: May 4, 2001
Creator: Lambert, H & Johnson, G
Object Type: Report
System: The UNT Digital Library
An Analysis of Gas Pressure Forming of Superplastic AL 5083 Alloy (open access)

An Analysis of Gas Pressure Forming of Superplastic AL 5083 Alloy

Al 5083 disks of a superplastic forming grade were gas-pressure formed to hemispheres and cones at constant forming pressures with and without back pressure. The forming operation was performed using an in-house designed and built biaxial forming apparatus. The temporal change of dome heights of the hemispheres and cones were measured for the different forming and back pressures applied. The flow stresses and strain rates developed at the top of the dome during the forming step were shown to closely follow the flow stress-strain rate relationship obtained from the strain rate change tests performed at the same temperature using uniaxial tensile samples.
Date: May 4, 2001
Creator: Syn, C K; O'Brien, M J; Lesuer, D R & Sherby, O D
Object Type: Article
System: The UNT Digital Library
Waveforms Measured in Confined Thermobaric Explosion (open access)

Waveforms Measured in Confined Thermobaric Explosion

Experiments with 1.5-g Shock-Dispersed-Fuel (SDF) charges have been conducted in six different chambers. Both flake Aluminum and TNT were used as the fuel. Static pressure gauges on the chamber wall were the main diagnostic. Waveforms for explosions in air were significantly larger than those in nitrogen - thereby demonstrating a strong thermobaric (combustion) effect. This effect increases as the confinement volume decreases and the mixture richness approaches 1.
Date: May 4, 2007
Creator: Reichenbach, H; Neuwald, P & Kuhl, A L
Object Type: Article
System: The UNT Digital Library
Review of cooling tower drift deposition models (open access)

Review of cooling tower drift deposition models

The behavior, basic assumptions, and limitations of ten different models for calculating the drift deposition rate from wet cooling towers are reviewed and then their predicted results for such deposition with a common set of input parameters are compared. The predicted maximum deposition differs among the models by two orders of magnitude with a wide range in peak location. Comments and suggestions to improve the models are included.
Date: May 4, 1977
Creator: Chen, N. C. J.
Object Type: Report
System: The UNT Digital Library
Saturation and Dynamic Range of Microchannel Plate-Based X-Ray Imagers (open access)

Saturation and Dynamic Range of Microchannel Plate-Based X-Ray Imagers

This paper describes recent advances in Monte Carlo simulations of microchannel plate (MCP)–based x-ray detectors, a continuation of ongoing work in this area. A Monte Carlo simulation model has been developed over the past several years by National Security Technologies, LLC (NSTec). The model simulates the secondary electron emission process in an MCP pore and includes the effects of gain saturation. In this work we focus on MCP gain saturation and dynamic range. We have performed modeling and experimental characterizations of L/D = 46, 10-micron diameter, MCP-based detectors. The detectors are typically operated by applying a subnanosecond voltage pulse, which gates the detector on. Agreement between the simulations and experiment is very good for a variety of voltage pulse waveforms ranging in width from 150 to 300 ps. The results indicate that such an MCP begins to show nonlinear gain around 5 × 10^4 electrons per pore and hard saturation around 105 electrons per pore. The simulations show a difference in MCP sensitivity vs voltage for high flux of photons producing large numbers of photoelectrons on a subpicosecond timescale. Simulations and experiments both indicate an MCP dynamic range of 1 to 10,000, and the dynamic range depends on how the …
Date: May 4, 2012
Creator: unknown
Object Type: Article
System: The UNT Digital Library
Review of electron-beam welding studies utilizing x-ray spectroscopy (open access)

Review of electron-beam welding studies utilizing x-ray spectroscopy

A review is presented of results obtained using an X-ray spectroscopy technique to study the electron-beam welding process. Results show that the technique is well suited for this kind of study. In particular, accurate voltage control is possible, and such control reduces weld-penetration variations significantly. Analytical techniques developed for studying noise on electron beams have general applicability for signal analysis. The work also shows that no voltage or current pulses were seen, and that the noise on the beam is probably not significant with respect to weld variations.
Date: May 4, 1977
Creator: Dixon, R. D.
Object Type: Report
System: The UNT Digital Library
MPI Runtime Error Detection with MUST: Advances in Deadlock Detection (open access)

MPI Runtime Error Detection with MUST: Advances in Deadlock Detection

None
Date: May 4, 2012
Creator: Hilbrich, T; Protze, J; Schulz, M; de Supinski, B & Mueller, M
Object Type: Article
System: The UNT Digital Library
2010 Atmospheric System Research (ASR) Science Team Meeting Summary (open access)

2010 Atmospheric System Research (ASR) Science Team Meeting Summary

This document contains the summaries of papers presented in poster format at the March 2010 Atmospheric System Research Science Team Meeting held in Bethesda, Maryland. More than 260 posters were presented during the Science Team Meeting. Posters were sorted into the following subject areas: aerosol-cloud-radiation interactions, aerosol properties, atmospheric state and surface, cloud properties, field campaigns, infrastructure and outreach, instruments, modeling, and radiation. To put these posters in context, the status of ASR at the time of the meeting is provided here.
Date: May 4, 2011
Creator: Dupont, D. L.
Object Type: Text
System: The UNT Digital Library
Mound Laboratory activities in chemical and physical research: July--December 1976. [Isotope separation; metal hydride research, separation chemistry and separation research] (open access)

Mound Laboratory activities in chemical and physical research: July--December 1976. [Isotope separation; metal hydride research, separation chemistry and separation research]

The status of the following programs is reported: isotope separation of carbon, argon, helium, krypton, neon, xenon, oxygen, and sulfur; metal hydride research; separation chemistry; and separation research. (LK)
Date: May 4, 1977
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Numerical Simulations of Thermobaric Explosions (open access)

Numerical Simulations of Thermobaric Explosions

A Model of the energy evolution in thermobaric explosions is presented. It is based on the two-phase formulation: conservation laws for the gas and particle phases along with inter-phase interaction terms. It incorporates a Combustion Model based on the mass conservation laws for fuel, air and products; source/sink terms are treated in the fast-chemistry limit appropriate for such gas dynamic fields. The Model takes into account both the afterburning of the detonation products of the booster with air, and the combustion of the fuel (Al or TNT detonation products) with air. Numerical simulations were performed for 1.5-g thermobaric explosions in five different chambers (volumes ranging from 6.6 to 40 liters and length-to-diameter ratios from 1 to 12.5). Computed pressure waveforms were very similar to measured waveforms in all cases - thereby proving that the Model correctly predicts the energy evolution in such explosions. The computed global fuel consumption {mu}(t) behaved as an exponential life function. Its derivative {dot {mu}}(t) represents the global rate of fuel consumption. It depends on the rate of turbulent mixing which controls the rate of energy release in thermobaric explosions.
Date: May 4, 2007
Creator: Kuhl, A L; Bell, J B; Beckner, V E & Khasainov, B
Object Type: Article
System: The UNT Digital Library
Design and Construction of a 15 T, 120 mm Bore Ir Quadrupole Magnet for LARP (open access)

Design and Construction of a 15 T, 120 mm Bore Ir Quadrupole Magnet for LARP

Pushing accelerator magnets beyond 10 T holds a promise of future upgrades to machines like the Large Hadron Collider (LHC) at CERN. Nb{sub 3}Sn conductor is at the present time the only practical superconductor capable of generating fields beyond 10 T. In support of the LHC Phase-II upgrade, the US LHC Accelerator Research Program (LARP) is developing a large bore (120 mm) IR quadrupole (HQ) capable of reaching 15 T at its conductor peak field and a peak gradient of 219 T/m at 1.9 K. While exploring the magnet performance limits in terms of gradient, forces and stresses the 1 m long two-layer coil will demonstrate additional features such as alignment and accelerator field quality. In this paper we summarize the design and report on the magnet construction progress.
Date: May 4, 2009
Creator: Caspi, S.; Cheng, D.; Dietderich, D.; Felice, H.; Ferracin, P.; Hafalia, R. et al.
Object Type: Article
System: The UNT Digital Library
Prestressed concrete reactor vessel thermal cylinder model study (open access)

Prestressed concrete reactor vessel thermal cylinder model study

The thermal cylinder experiment was designed both to provide information for evaluating the capability of analytical methods to predict the time-dependent stress-strain behavior of a /sup 1///sub 6/-scale model of the barrel section of a single-cavity prestressed concrete reactor vessel and to demonstrate the structural behavior under design and off-design thermal conditions. The model was a thick-walled cylinder having a height of 1.22 m, a thickness of 0.46 m, and an outer diameter of 2.06 m. It was prestressed both axially and circumferentially and subjected to 4.83 MPa internal pressure together with a thermal crossfall imposed by heating the inner surface to 338.8 K and cooling the outer surface to 297.1 K. The initial 460 days of testing were divided into time periods that simulated prestressing, heatup, reactor operation, and shutdown. At the conclusion of the simulated operating period, the model was repressurized and subjected to localized heating at 505.4 K for 84 days to produce an off-design hot-spot condition. Comparisons of experimental data with calculated values obtained using the SAFE-CRACK finite-element computer program showed that the program was capable of predicting time-dependent behavior in a vessel subjected to normal operating conditions, but that it was unable to accurately predict …
Date: May 4, 1977
Creator: Callahan, J. P.; Canonico, D. A.; Richardson, M.; Corum, J. M.; Dodge, W. G.; Robinson, G. C. et al.
Object Type: Report
System: The UNT Digital Library
Production of Diesel Engine Turbocharger Turbine from Low Cost Titanium Powder (open access)

Production of Diesel Engine Turbocharger Turbine from Low Cost Titanium Powder

Turbochargers in commercial turbo-diesel engines are multi-material systems where usually the compressor rotor is made of aluminum or titanium based material and the turbine rotor is made of either a nickel based superalloy or titanium, designed to operate under the harsh exhaust gas conditions. The use of cast titanium in the turbine section has been used by Cummins Turbo Technologies since 1997. Having the benefit of a lower mass than the superalloy based turbines; higher turbine speeds in a more compact design can be achieved with titanium. In an effort to improve the cost model, and develop an industrial supply of titanium componentry that is more stable than the traditional aerospace based supply chain, the Contractor has developed component manufacturing schemes that use economical Armstrong titanium and titanium alloy powders and MgR-HDH powders. Those manufacturing schemes can be applied to compressor and turbine rotor components for diesel engine applications with the potential of providing a reliable supply of titanium componentry with a cost and performance advantage over cast titanium.
Date: May 4, 2012
Creator: Muth, T. R. & Mayer, R. (Queen City Forging)
Object Type: Report
System: The UNT Digital Library
Estimated heat capacity, enthalpy, thermal conductivity, and diffusivity of solid D-T (open access)

Estimated heat capacity, enthalpy, thermal conductivity, and diffusivity of solid D-T

A program conducted to estimate the physical properties of the thermonuclear fusion fuel, D-T (actually the mixture deuterium-deuterium tritide-tritium) is described. The literature is reviewed on the heat capacity and thermal conductivity of solid hydrogen, hydrogen deuteride, and deuterium. Discussions are included on heat capacity and its attendant enthalpy deals with the crystal lattice, rotational, and quadrupolar mechanisms. For thermal conductivity, phonon scattering at crystallite boundaries and self-collisions (Umklapp processes) that reduce the phonon mean free path are described. The effects of rotational energy in either reducing crystallite size or causing phonon scattering from quadrupolar sublevels are discussed. Thermal diffusivity is derived from these properties plus density. An estimate of all the properties for the solid D-T mixture is included. Thermal conductivity and diffusivity prove especially interesting because they may vary as much as five orders of magnitude as a function of temperature, rotational energy, and radiation damage.
Date: May 4, 1976
Creator: Souers, P. C. & Tsugawa, R. T.
Object Type: Report
System: The UNT Digital Library
Status of Electron-Cloud Build-Up Simulations for the Main Injector (open access)

Status of Electron-Cloud Build-Up Simulations for the Main Injector

We provide a brief status report on measurements and simulations of the electron cloud in the Fermilab Main Injector. Areas of agreement and disagreement are spelled out, along with their possible significance.
Date: May 4, 2009
Creator: Furman, M. A.; Kourbanis, I. & Zwaska, R. M.
Object Type: Article
System: The UNT Digital Library
Local sodium boiling in a partially blocked simulated LMFBR subassembly (THORS Bundle 3B) (open access)

Local sodium boiling in a partially blocked simulated LMFBR subassembly (THORS Bundle 3B)

Experimental data from local sodium boiling tests with and without argon gas injection have been analyzed. The experiments were conducted with a 19-rod simulated LMFBR subassembly having the six central flow channels (12% of flow area) blocked in the heated section of the bundle. The data analysis shows that, without gas injection, local boiling in the blockage wake does not radially propagate to the surrounding free stream during two quasi-steady-state boiling periods of 13 and 27 sec. However, in tests with argon gas void fractions of 0.001 and 0.004, there is some evidence that the local boiling zone did spread but did not encompass the entire bundle cross section. An idealized extrapolation to full-size LMFBR subassemblies shows that the results with the 19-rod bundle are conservative. Analysis of data from nonboiling tests with gas injection shows that for void fractions between 0.00009 and 0.00354, the maximum temperature increase in the blockage wake due to gas injection is 40/sup 0/C (70/sup 0/F).
Date: May 4, 1977
Creator: Hanus, N.; Gnadt, P. A.; Fontana, M. H. & Wantland, J. L.
Object Type: Report
System: The UNT Digital Library