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30,213 Matching Results
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Presence of UV-endonuclease sensitive sites in daughter DNA of UV-irradiated mammalian cells. [3H-thymidine tracer]
Asynchronous Chinese hamster cells were irradiated with 10 Jm/sup -2/ uv radiation and 0.25 to 4 hours later pulse-labeled with (/sup 3/H)thymidine. Cells synchronized by shaking off mitotic and G/sub 1/ cells were irradiated in either the G/sub 1/-phase or S-phase of the cell cycle and pulse-labeled with (/sup 3/H)thymidine in the S-phase. After a 12 to 14 hour chase in unlabeled medium, the DNA was extracted, incubated with Micrococcus luteus uv-endonuclease and sedimented in alkaline sucrose. The number of endonuclease sensitive sites decreased as the time between uv irradiation and pulse-labeling of daughter DNA increased. Further, there were significantly less endonuclease sensitive sites in the daughter DNA from cells irradiated in the G/sub 1/-phase than in the S-phase. These data indicate that very few, if any, dimers are transferred from parental DNA to daughter DNA and that the dimers detected in daughter DNA may be due to the irradiation of replicating daughter DNA before labeling.
Date:
February 1, 1978
Creator:
D'Ambrosio, S. & Setlow, R.B.
Object Type:
Article
System:
The UNT Digital Library
Experimental investigation of the chemistry of excited states of rare gases. First quarterly progress report, October 15, 1977--January 15, 1978
The quenching of XeF(B) was studied using the steady-state photolysis of XeF/sub 2/ as the source of XeF(B). The product states from the sensitized reaction of Xe(/sup 3/P/sub 1/) with Cl/sub 2/ and COCl/sub 2/ also were studied. The new XeF(B) quenching rate constants are described. The pulsed laser induced fluorescence technique was used to measure radiative lifetimes and two-body quenching rate constant (with Ar) for the low energy Xe(6p)* states. Serious signal/noise problems for the lowest two states in the Xe(6p) manifold were encountered. A transient digitizer is on order, which should improve the signal/noise by a factor of 10. The Xe(6p)* work can then be completed. The radiative branching ratios of all the Ar(4p), Kr(5p) and Xe(6p) states were measured. Combining these branching ratios with the measured radiative lifetimes permits the assignment of the oscillator strengths for the Ar(4s-4p), Kr(5s-5p) and Xe(6s-6p) optical transitions. The manuscript describing the Ar(4p) work is complete (except for editing).
Date:
February 1978
Creator:
Setser, D. W.
Object Type:
Report
System:
The UNT Digital Library
Existence of fcc TiCr/sub 1/ /sub 8/H/sub 5/ /sub 3/
Originally an orthorhombic structure was assigned to the non-stoichiometric hydride TiCr/sub 1/ /sub 8/H/sub 3/ /sub 6/. Recent neutron and x-ray diffraction data indicated, however, that an alternate interpretation was possible, i.e. the solid consists of two hydride phases, an ..cap alpha..' Laves phase having a composition of TiCr/sub 1/ /sub 8/H/sub 2/ /sub 8/ and an fcc phase with a much higher hydrogen content. This proved to be the case and it has been determined that the high concentration phase has a disordered fluorite structure with a/sub o/=4.27 A. Its hydrogen content, as estimated from diffraction peak intensities, corresponds to TiCr/sub 1/ /sub 8/H/sub 5/ /sub 3/. We have not been able to produce single phase fcc material but have prepared a mixed phase sample with an overall composition of TiCr/sub 1/ /sub 8/H/sub 4/ /sub 8/. The high-pressure reaction leading to the formation of the fluorite phase is very sluggish and irreversible. Pressure-composition-temperature (p-c-T) properties of this system have been determined and are discussed and a revised phase diagram is proposed.
Date:
February 1, 1982
Creator:
Johnson, J. R.; Reilly, J. J.; Reidinger, F.; Corliss, L. M. & Hastings, J. M.
Object Type:
Article
System:
The UNT Digital Library
Nonlinear gyrokinetic theory for finite-BETA plasmas
A self-consistent and energy-conserving set of nonlinear gyrokinetic equations, consisting of the averaged Vlasov and Maxwell's equations for finite-..beta.. plasmas, is derived. The method utilized in the present investigation is based on the Hamiltonian formalism and Lie transformation. The resulting formation is valid for arbitrary values of k/perpendicular//rho//sub i/ and, therefore, is most suitable for studying linear and nonlinear evolution of microinstabilities in tokamak plasmas as well as other areas of plasma physics where the finite Larmor radius effects are important. Because the underlying Hamiltonian structure is preserved in the present formalism, these equations are directly applicable to numerical studies based on the existing gyrokinetic particle simulation techniques. 31 refs.
Date:
February 1, 1988
Creator:
Hahm, T. S.; Lee, W. W. & Brizard, A.
Object Type:
Report
System:
The UNT Digital Library
Analysis of x-ray production in TMX upgrade
TMX Upgrade (TMX-U), a tandem mirror experiment at LLNL, will use high power microwaves for electron cyclotron resonant heating (ECRH). As demonstrated on Elmo Bumpy Torus (EBT) and related experiments which use similar heating techniques, high energy electron populations are created. In these devices, which run CW, significant x-ray production occurs and adequate shielding must be provided for personnel protection. TMX-U is a pulsed experiment; however, significant x-ray production is expected from the 50 keV mean energy electron population. In this report the expected x-ray generation is calculated and the provisions for shielding are described. Based upon these calculations, as well as scaling estimates from other devices, the provided shielding is shown to be adequate for hot electron temperatures of interest for the experiment.
Date:
February 4, 1982
Creator:
Stallard, B. & Stephens, L.
Object Type:
Report
System:
The UNT Digital Library
Array automated assembly: Phase 2. Quarterly report
An analysis was made of cost trade-offs for shaping modified square wafers from cylindrical crystals. For reasonably expectable silicon and sheet costs, the optimum shape will be nearer a circle than a square. Tests were conducted of the effectiveness of texture etching for removal of surface damage on sawed wafers. Four glass systems have survived preliminary screening tests for use as edge masking dielectrics. These include beta-spodumen, MgO-Al/sub 2/O/sub 3/ borosilicate, baria and titania glasses. Aluminum contact metallization does not appear promising, and six silver screen printing inks have been selected for detailed investigation. Screening tests are underway for the selection of adhesive and coating materials for the superstrate fabrication. Three adhesive candidate materials have been identified for detailed investigation.
Date:
February 1, 1978
Creator:
Taylor, W.E.
Object Type:
Report
System:
The UNT Digital Library
MHD kink-driven instabilities in net-current-free stellarators
The Pfirsch-Schlueter current, which is induced in a toroidal device to keep the plasma current diverence-free, is shown to drive a free-boundary instability in a model of a net-current-free ATF-1 stellarator if <..beta..> = 2.6%.
Date:
February 1, 1984
Creator:
Rewoldt, G. & Johnson, J. L.
Object Type:
Report
System:
The UNT Digital Library
TRAC-PF1: an advanced best-estimate computer program for pressurized water reactor analysis
The Transient Reactor Analysis Code (TRAC) is being developed at the Los Alamos National Laboratory to provide advanced best-estimate predictions of postulated accidents in light water reactors. The TRAC-PF1 program provides this capability for pressurized water reactors and for many thermal-hydraulic experimental facilities. The code features either a one-dimensional or a three-dimensional treatment of the pressure vessel and its associated internals; a two-phase, two-fluid nonequilibrium hydrodynamics model with a noncondensable gas field; flow-regime-dependent constitutive equation treatment; optional reflood tracking capability for both bottom flood and falling-film quench fronts; and consistent treatment of entire accident sequences including the generation of consistent initial conditions. This report describes the thermal-hydraulic models and the numerical solution methods used in the code. Detailed programming and user information also are provided.
Date:
February 1, 1984
Creator:
Liles, D.R. & Mahaffy, J.H.
Object Type:
Report
System:
The UNT Digital Library
HYDROLOGIC AND GEOLOGIC STUDIES FOR PROJECT GNOME. Preliminary Report
Geologic lnformation required to define the pre- and post-shot physical and chemical characteristics of the sait and other rocks affected by the exploslon was gathered. Information on the pre- and post-shot hydrologic condltlons at the site and the surrounding area was also obtalned. (M.C.G.)
Date:
February 1, 1962
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Energy confinement scaling in tokamaks: some implications of recent experiments with ohmic and strong auxiliary heating
Recent results from confinement scaling experiments on tokamaks with ohmic and strong auxiliary heating are reviewed. An attempt is made to draw these results together into a low-density ohmic confinement scaling law, and a scaling law for confinement with auxiliary heating. The auxiliary heating confinement law may also serve to explain the saturation in tau/sub E/ vs anti n/sub e/ observed in some ohmic heating density scaling experiments.
Date:
February 1, 1984
Creator:
Goldston, R.J.
Object Type:
Report
System:
The UNT Digital Library
High resolution positron Q-value measurements and nuclear structure studies far from the stability line. Progress report
Research progress in briefly described, and details are presented in the attached preprints and reprints: (1) precision mass differences in light rubidium and krypton isotopes utilizing beta endpoint measurements; (2) precision mass measurements utilizing beta endpoints; (3) Monte Carlo calculations predicting the response of intrinsic GE detectors to electrons and positrons; and (4) reactor antineutrino spectra and nuclear spectroscopy of isotopes far from beta stability. (WHK)
Date:
February 28, 1982
Creator:
Avignone, F. T. III
Object Type:
Report
System:
The UNT Digital Library
LLL Geothermal Energy Development Program. Status Report, January 1974--January 1975. [Impulse Turbines, Total Flow Conversion Systems]
None
Date:
February 14, 1975
Creator:
Austin, A. L.
Object Type:
Report
System:
The UNT Digital Library
Engineering research on positive displacement gas expanders. Phase I technical report
A research, design, and development program related to positive displacement gas expanders is reported. The objective of this program is to develop and demonstrate a more cost effective gas expander for use in those waste heat recovery systems which utilize an Organic Rankine Cycle. To provide a lower cost machine, the gas expander uses a positive displacement concept, rather than a turbine as currently used. Several positive displacement machine concepts were examined, and various performance measures have been developed for each of the concepts. The machine concepts were: single and multiple cylinder reciprocators, radial piston, roller piston, sliding vane, trochoidal, helical screw, and lobed rotor. For each of the concepts, designs were generated for machines operating with three different sets of operating conditions. These designs were then used to develop measures of efficiency and cost, and to examine other characteristics of the machines, such as development risk and ability to operate with different flow, pressure, and temperature levels. Based upon an evaluation of these characteristics, a specific concept was selected for further development. This concept is a double acting, single cylinder reciprocating machine with crossheads and ceramic liners.
Date:
February 1, 1984
Creator:
Lord, R. E.
Object Type:
Report
System:
The UNT Digital Library
Assessment of the potential of colloidal fuels in future energy usage. Final report. [97 references]
Pulverized coal has been an increasing important source of energy over the past century. Most large utility boilers, all modern coking plants, and many industrial boilers and blast furnaces employ pulverized coal as a major feed stream. In periods of oil shortages, such as during World Wars I and II, the concept of adding powdered coal to oil for use in combustion equipment originally designed for oil has been actively pursued but rarely used. Over this same period of time, there have been attempts to use air suspensions of coal dust in diesel engines in Germany, and in turbines in various countries. The economic advantages to be enjoyed by substitution of powdered coal in oil are not generally realized. Oil costs at $30/bbl represent a fuel value of about $5.00/10/sup 6/ Btu; coal at $25/ton is equivalent to approximately $1.00/10/sup 6/ Btu. Although capital costs for the use of coal are higher than those associated with the use of oil, coal is clearly becoming the least costly fuel. Not only are considerable cost advantages possible, but an improvement in balance of payments and an increase in reliability of fuel supplies are other potential benefits. It is therefore recommended that increased …
Date:
February 25, 1980
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Safety assessment for the S-1 Spheromak
The S-1 machine is part of the Magnetic Fusion Program. The goal of the Magnetic Fusion Program is to develop and demonstrate the practical application of fusion. S-1 is an experimental device which will provide an essential link in the research effort aiming at the realization of fusion power.
Date:
February 1, 1984
Creator:
Ellis, R., Jr. & Stencel, J. R.
Object Type:
Report
System:
The UNT Digital Library
Uranium Hydrogeochemical and Stream Sediment Reconnaissance in southwestern Montana
The Los Alamos Scientific Laboratory conducted a Hydrogeochemical and Stream Sediment Reconnaissance in southwestern Montana from early August to mid-October of 1976. A total of 1240 water and 1933 sediment samples were collected from 1994 locations at a nominal density of one location per 10 km/sup 2/. The water samples were collected from streams, wells, and springs; sediment samples were taken at streams and springs. All samples were analyzed at Los Alamos for total uranium by fluorometry or delayed-neutron counting. The uranium content of water samples ranges from below the detection limit (less than 0.3 ppB) to 45.30 ppB and has a mean value of 1.40 ppB. The uranium content of the sediment samples ranges between 0.20 and 206.80 ppM and averages 6.12 ppM. The chosen uranium anomaly threshold value was 7 ppB for surface waters (streams), 9 ppB for groundwaters (wells and springs), and 25 ppM for all sediment samples. The study area consists of the following lithologic groups: Precambrian basement complex, Precambrian Belt metasediments, Paleozoic and Mesozoic shelf sediments, Cretaceous and early Tertiary volcanic and plutonic rocks, Laramide orogenic clastic sediments, and middle to late Tertiary volcanic rocks and intermontane basin sediments. Most of the anomalous water and …
Date:
February 1, 1978
Creator:
Broxton, D. E.
Object Type:
Report
System:
The UNT Digital Library
Isotope applications in the environmental field
Established uses of enriched isotopes in the environmental field were surveyed to determine future trends in isotope needs. Based on established isotope uses, on the projected increase in the pollution problem, and on the apparent social and economic pressure for pollution abatement, a significant demand for enriched isotopes appears to be developing for the assessment and control of air, water, and soil pollutants. Isotopic techniques will be used in combination with conventional methods of detection and measurement, such as gas chromatography, x-ray fluorescence, and atomic absorption. Recent advances in economical isotope separation methods, instrumentation, and methodology promise to place isotopic technology within the reach of most research and industrial institutions. Increased application of isotope techniques appears most likely to occur in areas where data are needed to characterize the movement, behavior, and fate of pollutants in the environment.
Date:
February 17, 1978
Creator:
DeWitt, R.
Object Type:
Report
System:
The UNT Digital Library
Design of photovoltaic central power station concentrator array
A design for a photovoltaic central power station using tracking concentrators has been developed. The 100 MW plant is assumed to be located adjacent to the Saguaro Power Station of Arizona Public Service. The design assumes an advanced Martin Marietta two-axis tracking fresnel lens concentrator. The concentrators are arrayed in 5 MW subfields, each with its own power conditioning unit. The photovoltaic plant output is connected to the existing 115 kV switchyard. The site specific design allows detailed cost estimates for engineering, site preparation, and installation. Collector and power conditioning costs have been treated parametrically.
Date:
February 1, 1984
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
On-line chemical composition analyzer development
The energy consumed in distillation processes in the United States represents nearly three percent of the total national energy consumption. If effective control of distillation columns can be accomplished, it has been estimated that it would result in a reduction in the national energy consumption of 0.3%. Real-time control based on mixture composition could achieve these savings. However, the major distillation processes represent diverse applications and at present there does not exist a proven on-line chemical composition sensor technology which can be used to control these diverse processes in real-time. This report presents a summary of the findings of the second phase of a three phase effort undertaken to develop an on-line real-time measurement and control system utilizing Raman spectroscopy. A prototype instrument system has been constructed utilizing a Perkin Elmer 1700 Spectrometer, a diode pumped YAG laser, two three axis positioning systems, a process sample cell land a personal computer. This system has been successfully tested using industrially supplied process samples to establish its performance. Also, continued application development was undertaken during this Phase of the program using both the spontaneous Raman and Surface-enhanced Raman modes of operation. The study was performed for the US Department of Energy, Office …
Date:
February 1, 1992
Creator:
Roberts, M.J.; Garrison, A.A.; Muly, E.C. & Moore, C.F.
Object Type:
Report
System:
The UNT Digital Library
Simple measurement of line density
Energy line density, E/sub l/ = ..integral..(F/2)nk(T/sub e/ + T/sub i/)dA, has proved to be one of the easiest (and most critical) measurements made on the Scylla IV-P, 5-m linear theta pinch. A quantitative evaluation of end-stoppering techniques is made available by extracting the line energy containment time, tau/sub E/sub l//, from the time history of E/sub l/. To model E/sub l/(t) properly and, hence, determine the details of energy loss mechanisms (streaming and thermal conduction) requires separate measurements of n and T. A simple measurement of line density, n/sub l/ = ..integral..ndA, is proposed, in which a single laser beam is passed repeatedly through the plasma column along different chords. A discussion is presented of the measurement accuracy as a function of the number of passes.
Date:
February 1, 1978
Creator:
Armstrong, W.T. & Siemon, R.E.
Object Type:
Report
System:
The UNT Digital Library
A Theoretical Study of Destructive Nuclear Bursts in Fast Power Reactors
The calculation of destructive nuclear bursts in fast reactors by an improved Bethe-Tait method, which, for purposes of calculation, neglects propagation of the pressure wave is described. TMen exact numerical calculations for hydrodynamic and neutronic conditions during the power burst are performed in order to assess the importance of this neglect. (auth)
Date:
February 1, 1962
Creator:
Jankus, V. Z.
Object Type:
Report
System:
The UNT Digital Library
Insertion device and beam line plans for the Advanced Photon Source: A report and recommendations by the Insertion Device and Beam Line Planning Committee
In the 7-GeV Advanced Photon Source (APS) Conceptual Design Report (CDR), fifteen complete experimental beam lines were specified in order to establish a representative technical and cost base for the components involved. In order to optimize the composition of the insertion devices and the beam line, these funds are considered a ''Trust Fund.'' The present report evaluates the optimization for the distribution of these funds so that the short- and long-term research programs will be most productive, making the facility more attractive from the user's point of view. It is recommended that part of the ''Trust Fund'' be used for the construction of the insertion devices, the front-end components, and the first-optics, minimizing the cost to potential users of completing a beam line. In addition, the possibility of cost savings resulting from replication and standardization of high multiplicity components (such as IDs, front ends, and first-optics instrumentation) is addressed. 2 refs., 5 tabs.
Date:
February 1, 1988
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
HC quench layer formation in combustion processes. Technical progress report, September-December 1979
The project is aimed at understanding wall quenching and other processes responsible for surface generated hydrocarbons in combustion under engine-like conditions. The study concerns the effects of turbulence on the evolution of hydrocarbons. At the conclusion of the program, significant new experimental information will have been generated and an analytical model of the fluid mechanics and some aspects of the chemistry of quenching will be formulated. The work is divided into three tasks: (1) combustion bomb experiments to measure the effect of turbulence on the chemical species near the cold surface; combustion bomb experiments, using a similar turbulence generating device, to fully characterize the flow and turbulence in the vicinity of the quenching surface, and an analytical study to characterize fluid mechanical scales of interest in the boundary layer and to find an analytical solution to describe the evolution of the layer. The major accomplishments to date are (i) demonstration of the feasibility of single shot sampling valve operation and gas analysis in the Ford bomb under laminar combustion conditions, (ii) formulation of design rationale for turbulence generation scheme and bomb geometry, and (iii) formulation of an approach to modeling turbulent boundary layer conditions.
Date:
February 1, 1980
Creator:
Lavoie, G. A.
Object Type:
Report
System:
The UNT Digital Library
NIGHTMARE-AN IBM 7090 CODE FOR THE CALCULATION OF GAMMA HEATING IN CYLINDRICAL GEOMETRY
The NIGHTMARE program calculates the gamma-dose rate at any point in or near a reactor by means of the NDA buildup-factor method. The source distributton is obtained from a two-group, two-dimensional diffusion code (EQUIPOISE-2). Seven gamma-energy groups are used. As many as nine different concentric cylindrical regions may be considered, but only radial variation of attenuation and buildup properties is permdtted. Two schemes of estimating buildup factors through a succession of materials are built into the code, and results may be obtained by using either or both methods. An IBM 7090 computer wtth seven tape untts is required. Computations are performed at the approximate rate of l0,000/n mesh points per minute, where n is the number of axial, radial, and angular increments. The program is run under the control of the IBM 7090 MONITOR system. (auth)
Date:
February 26, 1962
Creator:
Tobias, M.L.; Vondy, D.R. & Lietzke, M.P.
Object Type:
Report
System:
The UNT Digital Library