68,615 Matching Results

Search Results

Results: 1 - 24 next
open access

Radiological survey of the inactive uranium-mill tailings at Falls City, Texas

Description: Results of a radiological survey conducted at the Falls City, Texas, site in July 1976 are presented. There are seven partial to fully stabilized tailings piles, and an overburden pile from an open-pit mine. Above ground gamma-ray exposure rate measurements show moderate levels of contamination throughout the area with a maximum exposure rate of 500 ..mu..R/hr above tailings pile 2. The average exposure rate over the different areas varied from 14 ..mu..R/hr over the southwest end of tailings pile 7 to 207 ..mu..R/hr over the northeast end of the same pile. Analyses of surface soil and dry-wash sediment samples, as well as calculations of subsurface /sup 226/Ra distribution, serve to define the spread of tailings around the area. Water erosion of the tailings is evident, but, because of abundant growth of vegetation on the tailings piles, wind erosion probably is not a major problem.
Date: October 1, 1980
Creator: Haywood, F. F.; Christian, D. J.; Loy, E. T.; Lorenzo, D. & Ellis, B. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Amplification of a bi-phase shift-key modulated signal by a mm-wave FEL

Description: Bi-phase shift keying (BPSK) is a modulation scheme used in communications and radar in which the phase of a transmitted rf signal is switched in a coded pattern between discrete values differing by {pi} radians. The transmitted information rate (in communications) or resolution (in imaging radar) depends on the rate at which the transmitted signal can be modulated. Modulation rates of greater than 1 GHz are generally desired. Although the instantaneous gain bandwidth of a mm-wave FEL amplifier can be much greater than 10 GHz, slippage may limit the BPSK modulation rate that can be amplified. Qualitative slippage arguments would limit the modulation rate to relatively low values; nevertheless, simulations with a time-dependent FEL code (GINGER) indicate that rates of 2 GHz or more are amplified without much loss in modulation integrity. In this paper we describe the effects of slippage in the simulations and discuss the limits of simple arguments.
Date: October 1, 1991
Creator: Prosnitz, D.; Scharlemann, E.T. & Sheaffer, M.K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A comparison of predicted and observed turbulent wind fields present in natural and internal wind park environments

Description: This paper assesses the accuracy of simulated wind fields for both the natural flow and that within a wind park environment. The simulated fields are compared with the observed ones in both the time and frequency domains. Actual measurements of the wind fields and the derived kinematic scaling parameters upwind and downwind of a large San Gorgonio Pass wind park are used. The deviations in the modeled wind field from the observed are discussed. 10 refs., 6 figs., 2 tabs.
Date: October 1, 1991
Creator: Kelly, N D & Wright, A D
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Biliary Excretion of /Sup 99m/Tc Albumin Microaggregate Degradation Products (a Method for Measuring Kupffer Cell Digestive Function.).

Description: The rapid metabolism of radioactive albumin colloids used for liver-spleen-bone marrow scanning radiation exposure to these organs and permits one to study the proteolytic digestive capacity of the reticuloendothial system (RES)
Date: October 31, 1971
Creator: Kitani, K. & Taplin, G. V.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A unified theory of resonant excitation of kinetic ballooning modes by energetic ions/alpha particles in tokamaks

Description: A complete theory of wave-particle interactions is presented whereby both circulating and trapped energetic ions can destabilize kinetic ballooning modes in tokamaks. Four qualitatively different types of resonances, involving wave-precessional drift, wave-transit, wave-bounce, and precessional drift-bounce interactions, are identified, and the destabilization potential of each is assessed. For a characteristic slowing-down distribution function, the dominant interaction is that which taps those resonant ions with the highest energy. Implications of the theory for present and future generation fusion experiments are discussed. 16 refs.
Date: October 1, 1991
Creator: Biglari, H. & Chen, L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Non-linear instability of DIII-D to error fields

Description: Otherwise stable DIII-D discharges can become nonlinearly unstable to locked modes and disrupt when subjected to resonant m = 2, n = 1 error field caused by irregular poloidal field coils, i.e. intrinsic field errors. Instability is observed in DIII-D when the magnitude of the radial component of the m = 2, n = 1 error field with respect to the toroidal field is B{sub r21}/B{sub T} of about 1.7 {times} 10{sup {minus}4}. The locked modes triggered by an external error field are aligned with the static error field and the plasma fluid rotation ceases as a result of the growth of the mode. The triggered locked modes are the precursors of the subsequent plasma disruption. The use of an n = 1 coil'' to partially cancel intrinsic errors, or to increase them, results in a significantly expanded, or reduced, stable operating parameter space. Precise error field measurements have allowed the design of an improved correction coil for DIII-D, the C-coil'', which could further cancel error fields and help to avoid disruptive locked modes. 6 refs., 4 figs.
Date: October 1, 1991
Creator: La Haye, R. J. & Scoville, J. T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Fifth high-energy heavy-ion study

Description: This was the fifth of a continuing series of summer studies held at LBL to discuss high energy heavy ion collisions. Recently, a similar meeting has been held on alternate years at GSI (Darmstadt); and, in 1979, we held a meeting at LBL exclusively devoted to ultra-relativistic nuclear collisions. Two new features distinguish this study from earlier meetings in the series. First, the energy range for discussion was broadened by including collisions from about 20 MeV/nucleon to the highest available in the cosmic radiation. The lower range, particularly below 100 MeV/nucleon, will be under intense study in the near future with machines such as the upgraded Bevalac, Michigan State University Superconducting Cyclotron, GANIL in France, and the SC at CERN. Recently, the high energy collision regime has been expanded by the successful operation of the CERN ISR with alpha particles. Second, in addition to an extensive program of invited talks, we decided for the first time to actively solicit contributions. Forty-seven individual items from the conference were prepared separately for the data base. (GHT)
Date: October 1, 1981
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Recording Equipment for Internal Friction Measurements

Description: An apparatus was developed for recording internal friction data in such a manner as to circumvent many of the laborious and time-consuming observations and calculations usually associated with these measurements. An optical lever is used and the passage of the beam across the scale is detected by photoconductive cells. The cells are strategically located so that, when their signals are fed through a multichannel switching circuit to the pens of an operation recorder, a plot of the logarithm of the vibrational amplitude versus the number of cycles is recorded on the chart. From the definitmon of the logarithmic decrement, ( delta ), it can be shown that the slope of this curve is - delta . The apparatus is inexpensive and requires a minimum of maintenance. It has been used for accurate determinations of values of delta from below 0.0001 up to 0.3. (auth)
Date: October 31, 1961
Creator: Stephenson, R. L. & McCoy, H. E. Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

(Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

Description: This report presents information concerning field procedures employed during the monitoring, well construction, well purging, sampling, and well logging at the Wright-Patterson Air Force Base. Activities were conducted in an effort to evaluate ground water contamination.
Date: October 1, 1991
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Intermediate-depth geothermal temperature study. Gradient holes: 11-33 and 63-33, Soda Lake, NV

Description: During 1979, Chevron Resources Company drilled two 2000 ft holes near Soda Lake in the Nevada Carson Sink area to obtain subsurface data for inclusion in the US Department of Energy's Northern Basin and Range geothermal reservoir assessment program. Drilling information together with detailed lithologic, geophysical and temperature log data were compiled for each hole and is summarized in this report. Maximum stabilized temperatures of 297/sup 0/F and 367/sup 0/F were encountered at total depth in each of the holes, respectively.
Date: October 1, 1979
Creator: Hill, D.G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Establishment of viscometer capability for geopressured fluids. Project 61024 final report, November 19, 1978-December 31, 1979

Description: The feasibility of modifying the IGT capillary viscometer for the measurement of methane-saturated brines at 10,000 psi and 200/sup 0/C was evaluated. The viscometer was cleaned, modified, reassembled and pressure treated. The density cells were calibrated to a precision of approximately 7%. The viscosity of pure value was measured and the best value obtained was 6% below values reported in the literature. The operation of the viscometer was time-consuming and required meticulous cleaning between experiments. Some corrosion at the mercury surface interfered with the efficient operation of the timing device. Other problems were encountered due to gas bubbles trapped in the capillary flow path. Consequently, data on methane-saturated brine could not be obtained within the funding limitations of this program. It is concluded that further work on the existing viscometer would not be cost-effective.
Date: October 1, 1980
Creator: Rockar, E. & Randolph, P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

ORR Operations for Period April 1961 to April 1962

Description: A summary of the activities in the 4th operational year is presented for the ORR. On-stream time at 30 Mw was relatively steady with 75.4 and 83.7% representing the lowest and highest quarters. Modification of the ball-latch mechanism of the shim-rod-drives is in progress. The primary cooling system bypass control valve was modified and a d-c pony motor was added at the No. 3 primary pump. This addition was made to increase the reliability of adequate water flow for afterheat cooling. A study of coreboiling detection is being conducted. (J.R.D.)
Date: October 16, 1962
Creator: Binford, F.T.; Casto, W.R. & Colomb, A.L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Two-photon physics

Description: A new experimental frontier has recently been opened to the study of two photon processes. The first results of many aspects of these reactions are being presented at this conference. In contrast, the theoretical development of research ito two photon processes has a much longer history. This talk reviews the many different theoretical ideas which provide a detailed framework for our understanding of two photon processes.
Date: October 1, 1981
Creator: Bardeen, W.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Exploring novel silicon-containing polymers---From preceramic polymers to conducting polymers with nonlinear optical properties

Description: Several new types of silicon-containing preceramic polymers, i.e., poly(diorganosilacetylene) and poly(diorganosilvinylene) have been synthesized with molecular weights from 10,000 to 120,000. These polymers could be thermally converted to SiC with a moderate to high char yields. Ready solubility and good processability made these types of polymers attractive in their applications to ceramics. The thermal polymerization of diethynyldiphenyl-silane, which was reported in 1968 to afford poly(diphenylsilyldiacetylene) via dehydrogenation, was reinvestigated. Spectroscopic studies showed that the polymer had a structure of polyacetylene type not diacetylene. Diphenyldiethynylgermane and a series of diorganodiethynylsilances were synthesized. These could be polymerized in the presence of MoCl{sub 5} or WCl{sub 6} to afford a soluble, violet material with Mw as high as 108,000. 100 refs., 56 figs., 16 tabs.
Date: October 7, 1991
Creator: Pang, Yi.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Final Report of Modeling of CWM Droplet Combustion

Description: The objective of the present study was to develop a one-dimensional, unsteady state model for coal-water mixture droplet combustion, and to compare the characteristic times for the various processes, such as water vaporization, devolatilization and char oxidation with available experimental data. A water film surrounding a spherical coal particle is considered to undergo vaporization by heat transfer from the hot air. After the water vaporization is complete, devolatilization begins. This process is assumed to be kinetically controlled. Water vaporization and devolatilization processes are modeled by using a hybrid Eulerian-Lagrangian method to obtain the properties of the gas-phase and the condensed-phase. An explicit finite difference scheme is used to solve the Eulerian gas-phase equation where as a Runga-Kutta scheme is employed to solve the Lagrangian condensed-phase equations. The predicted characteristic times for water vaporization is in good agreement with values proposed in the literature. At the present time there is insufficient data to draw any conclusions on the model. Methods are proposed to refine the simple kinetic model which takes into account pore diffusion and mass transfer for devolatilization and char oxidation. 9 references, 12 figures.
Date: October 1, 1983
Creator: Pandalai, Krish; Aggarwal, Suresh & Sirignano, William
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Joining of ceramics for high performance energy systems. Mid-term progress report, August 1, 1979-March 31, 1980

Description: The subject program is primarily an exploratory and demonstration study of the use of silicate glass-based adhesives for bonding silicon-base refractory ceramics (SiC, Si/sub 3/N/sub 4/). The projected application is 1250 to 2050/sup 0/F relaxing joint service in high-performance energy conversion systems. The five program tasks and their current status are as follows. Task 1 - Long-Term Joint Stability. Time-temperature-transformation studies of candidate glass adhesives, out to 2000 hours simulated service exposure, are half complete. Task 2 - Environmental and Service Effects on Joint Reliability. Start up delayed due to late delivery of candidate glass fillers and ceramic specimens. Task 3 - Viscoelastic Damping of Glass Bonded Ceramics. Promising results obtained over approximately the same range of glass viscosity required for joint relaxation function (10/sup 7.5/ to 10/sup 9.5/ poise). Work is 90% complete. Task 4 - Crack Arrest and Crack Diversion by Joints. No work started due to late arrival of materials. Task 5 - Improved Joining and Fabrication Methods. Significant work has been conducted in the area of refractory pre-glazing and the application and bonding of high-density candidate glass fillers (by both hand-artisan and slip-spray techniques). Work is half complete.
Date: October 6, 1980
Creator: Smeltzer, C E & Metcalfe, A G
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Light Absorption and Scattering Mechanisms in Laser Fusion Plasmas

Description: The picture of laser light absorption and scattering which is emerging from theory and computer simulation studies of laser-plasma interactions is described. On the subject of absorption, we discuss theoretical and experimental evidence that resonance absorption in a steepened density profile is a dominant absorption mechanism. Recent work also indicates the presence of critical surface ripples, which we study using two and three dimensional computer simulations. Predictions of hot electron spectra due to resonance absorption are described, as are effects of plasma outflow. We then discuss two regimes where stimulated scattering may occur. Brillouin scattering is expected in the underdense target blow-off, for long laser pulses, and is limited by ion heating. Raman scattering in the background gas of a reactor target chamber is predicted to be at most a 10 percent effect for 1 ..mu..m lasers.
Date: October 4, 1977
Creator: Barnes, C.; Estabrook, K. G.; Kruer, W. L.; Langdon, A. B.; Lasinski, B. F.; Max, C. E. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Potential for efficient frequency conversion at high average power using solid state nonlinear optical materials

Description: High-average-power frequency conversion using solid state nonlinear materials is discussed. Recent laboratory experience and new developments in design concepts show that current technology, a few tens of watts, may be extended by several orders of magnitude. For example, using KD*P, efficient doubling (>70%) of Nd:YAG at average powers approaching 100 KW is possible; and for doubling to the blue or ultraviolet regions, the average power may approach 1 MW. Configurations using segmented apertures permit essentially unlimited scaling of average power. High average power is achieved by configuring the nonlinear material as a set of thin plates with a large ratio of surface area to volume and by cooling the exposed surfaces with a flowing gas. The design and material fabrication of such a harmonic generator are well within current technology.
Date: October 28, 1985
Creator: Eimerl, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
Back to Top of Screen