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A unified theory of resonant excitation of kinetic ballooning modes by energetic ions/alpha particles in tokamaks
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.
Object Type:
Report
System:
The UNT Digital Library
Non-linear instability of DIII-D to error fields
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.
Object Type:
Article
System:
The UNT Digital Library
(Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)
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
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Exploring novel silicon-containing polymers---From preceramic polymers to conducting polymers with nonlinear optical properties
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.
Object Type:
Report
System:
The UNT Digital Library
The interpretation of reflectometry measurements of plasma fluctuations
Wave reflections from density fluctuations with magnitudes and frequencies typical of drift waves have been investigated. Both drift waves and the reflected phase and amplitude depend on the density gradient scale length, and this common feature implies that both the angular deviation of a normally propagating wave and the phase change on reflection are of order unity. Thus the surface will always appear rough'' and amplitude variations will always be large. For smaller amplitude waves numerical solutions of the one dimensional full wave equation for the propagation near cutoff frequencies has been used to show how to interpret reflectometry measurements. For density perturbations with wavelengths near the density scale length, the external fluctuating phase can be simply interpreted in terms of a fluctuating density near the cutoff layer. However, the amplitude of the phase response falls substantially as the fluctuation wavelength, {Lambda}, approaches the free space wavelength of the reflected wave, {lambda}{sub o}, and the location of the maximum response moves out in front of the cutoff layer following the wave matching condition k{sub {Lambda}} = 2k {approx} 2{eta}(x)k{sub 0}. Similarly, correlation measurements of density fluctuations from probe waves of different wavelengths are shown to be limited to about four …
Date:
October 1, 1991
Creator:
Bretz, N.
Object Type:
Report
System:
The UNT Digital Library
Thermodynamic model for calorimetric and phase coexistence properties of coal derived fluids
On September 1, 1989 work was initiated on a project to extend the available vapor-liquid equilibrium (VLE) model for coal fluids to allow satisfactory predictions of excess enthalpies of coal liquids at high pressures. The available vapor liquid equilibrium model was developed with support from previous grant from DOE-PETC (Grant no. DE-FG22-89PC90541). The current project also involves measurement of some model compound VLE data and chromatographic characterization of coal liquids for distribution of heteroatoms. A computational thermodynamic model for VLE, excess enthalpies and heat capacities of coal derived liquids has been developed. The model uses the modified UNIFAC correlation for the liquid phase. Some unavailable UNIFAC interactions parameters have been regressed from experimental VLE and excess enthalpy data. The computations are carried out using the method of continuous thermodynamics. Mode is used to derive interesting conclusions on the effect of oxygen, nitrogen, and sulfur heteroatoms on the thermodynamic properties of coal liquids. When compared with limited experimental data available for coal liquids the model shows good agreement. Some progress has been made on binary VLE measurements and size exclusion chromatography of coal liquids.
Date:
October 1, 1991
Creator:
Kabadi, V. N.
Object Type:
Report
System:
The UNT Digital Library
The neutrinos in muon decay
We review the available information on the identity of the neutrino states emitted in muon decay, and discuss the exotic decay {mu}{sup +} {yields} e{sup +} {bar {nu}}{sub e}{nu}{sub {mu}}. 22 refs.
Date:
October 21, 1991
Creator:
Herczeg, P.
Object Type:
Article
System:
The UNT Digital Library
Research in theoretical nuclear physics
The work done during the past year covers three separate areas, low energy nuclear reactions intermediate energy physics, and nuclear structure studies. This manuscript summarizes our achievements made in these three areas.
Date:
October 1, 1991
Creator:
Udagawa, T.
Object Type:
Report
System:
The UNT Digital Library
A comparison of spanwise aerodynamic loads estimated from measured bending moments versus direct pressure measurements on horizontal axis wind turbine blades
Two methods can be used to determine aerodynamic loads on a rotating wind turbine blade. The first is to make direct pressure measurements on the blade surface. This is a difficult process requiring costly pressure instrumentation. The second method uses measured flap bending moments in conjunction with analytical techniques to estimate airloads. This method, called ALEST, was originally developed for use on helicopter rotors and was modified for use on horizontal axis wind turbine blades. Estimating airloads using flap bending moments in much simpler and less costly because measurements can be made with conventional strain gages and equipment. This paper presents results of airload estimates obtained using both methods under a variety of operating conditions. Insights on the limitations and usefulness of the ALEST bending moment technique are also included. 10 refs., 6 figs.
Date:
October 1, 1991
Creator:
Simms, D A & Butterfield, C P
Object Type:
Article
System:
The UNT Digital Library
Investigations of CuInSe sub 2 Thin Films and Contacts
This report describes research into electrical contacts for copper indium diselenide (CuInSe{sub 2}) polycrystalline thin films used for solar cell applications. Molybdenum contacts have historically been the most promising for heterojunction solar cells. This program studied contact stability by investigating thermally induced bilayer reactions between molybdenum and copper, indium, and selenium. Because selenization is widely used to fabricate CuInSe{sub 2} thin films for photovoltaic cells, a second part of the program investigated how the morphologies, phases, and reactions of pre-selenization Cu-In structures are affected by the deposition process and heat treatments. 7 refs., 6 figs.
Date:
October 1, 1991
Creator:
Nicolet, M. A.
Object Type:
Report
System:
The UNT Digital Library
Cationically polymerizable monomers derived from renewable sources
The objective of this project is to make use of products obtained from renewable plant sources as monomers for the direct production of polymers which can be used for a wide range of plastic applications. In this report is described progress in the synthesis and polymerization of cationically polymerizable monomers and oligomers derived from botanical oils, terpenes, natural rubber, and lignin. Nine different botanical oils were obtained from various sources, characterized and then epoxidized. Their photopolymerization was carried out using cationic photoinitiators and the mechanical properties of the resulting polymers characterized. Preliminary biodegradation studies are being conducted on the photopolymerized films from several of these oils. Limonene was cationically polymerized to give dimers and the dimers epoxidized to yield highly reactive monomers suitable for coatings, inks and adhesives. The direct phase transfer epoxidation of squalene and natural rubber was carried out. The modified rubbers undergo facile photocrosslinking in the presence of onium salts to give crosslinked elastomers. 12 refs., 3 figs., 10 tabs.
Date:
October 1, 1991
Creator:
Crivello, J. V.
Object Type:
Report
System:
The UNT Digital Library
Theoretical study of the structure, energetics, and dynamics of silicon and carbon systems using tight-binding approaches
Semiempirical interatomic potentials are developed for silicon and carbon by modeling the total energy of the system using tight-binding approaches. The parameters of the models were obtained by fitting to results from accurate first-principles Local Density Functional calculations. Applications to the computation of phonons as a function of volume for diamond-structured silicon and carbon and the thermal expansions for silicon and diamond yields results which agree well with experiment. The physical origin of the negative thermal expansion observed in silicon is explained. A tight-binding total energy model is generated capable of describing carbon systems with a variety of atomic coordinations and topologies. The model reproduces the total energy versus volume curves of various carbon polytypes as well as phonons and elastic constants of diamond and graphite. The model has also been used in the molecular-dynamics simulation of the properties of carbon clusters. The calculated ground-state geometries of small clusters (C{sub 2}--C{sub 10}) correlates well with results from accurate quantum chemical calculations, and the structural trend of clusters from C{sub 2} to C{sub 60} are investigated. 67 refs., 19 figs.
Date:
October 25, 1991
Creator:
Xu, Chunhui.
Object Type:
Report
System:
The UNT Digital Library
Tumors of the skin and soft tissues
The majority of the body surface is covered by the skin. Many internal disorders are reflected in the condition of the skin. One of the major functions of the skin is protection of the other organ systems from a variety of environmental insults. In this role, the skin itself is exposed to factors that can ultimately cause chronic diseases and cancer. Since it is relatively easy to recognize skin abnormalities, most skin cancers are brought to professional attention sooner than other types of cancer. However, due to the close resemblance between many skin neoplasms and noncancerous dermatologic disorders, these neoplasms may be mistreated for months or even years. In veterinary oncology, as in human medicine, most cancers can be effectively treated or cured following an accurate diagnosis. Once diagnosed, skin neoplasms should be aggressively treated. If causal factors are known, exposure to these factors should be limited through removal of the agent (for chemical carcinogens) or limiting exposure to the agent (for other carcinogens such as sunlight). 10 tabs. (MHB)
Date:
October 1, 1991
Creator:
Weller, R. E.
Object Type:
Article
System:
The UNT Digital Library
FY 1992 task plans for the Hanford Environmental Dose Reconstruction Project
Phase 1 of the HEDR Project was designed to develop and demonstrate a method for estimating radiation doses people may have received from Hanford Site operations since 1944. The method researchers developed relied on a variety of measured and reconstructed data as input to a modular computer model that generates dose estimates and their uncertainties. As part of Phase 1, researchers used the reconstructed data and computer model to calculate preliminary dose estimates for populations from limited radionuclides, in a limited geographical area and time period. Phase 1 ended in FY 1990. In February 1991, the TSP decided to shift the project planning approach away from phases--which were centered around completion of major portions of technical activities--to individual fiscal years (FYs), which span October of one year through September of the next. Therefore, activities that were previously designated to occur in phases are now designated in an integrated schedule to occur in one or more of the next fiscal years into FY 1995. Task plans are updated every 6 months. In FY 1992, scientists will continue to improve Phase 1 data and models to calculate more accurate and precise dose estimates. The plan for FY 1992 has been prepared based …
Date:
October 1, 1991
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Future aircraft and potential effects on stratospheric ozone and climate
The purpose of this study is to extend the recent research examining the global environmental effects from potential fleets of subsonic and supersonic commercial aircraft. Initial studies with LLNL models of global atmospheric chemical, radiative, and transport processes have indicated that substantial decreases in stratospheric ozone concentrations could result from emissions of NO{sub x} from aircraft flying in the stratosphere, depending on fleet size and magnitude of the engine emissions. These studies used homogeneous chemical reaction rates (e.g. gas-phase chemistry). Recent evidence indicates that reactions on particles in the stratosphere may be important. Heterogeneous chemical reactions, for instance, N{sub 2}O{sub 5}and ClONO{sub 2} on background sulfuric acid aerosols, convert NO{sub x}(NO and NO{sub 2}) molecules to HNO{sub 3}. This decreases the odd oxygen loss from the NO{sub x} catalytic cycle and increases the odd oxygen loss from the Cl{sub x} catalytic cycle. By including these heterogeneous reactions in the LLNL model, the relative partitioning of odd oxygen loss between these two families changes, with the result that emissions of NO{sub x} from proposed aircraft fleets flying in the stratosphere now increase zone. Having these heterogeneous processes present also increases ozone concentration in the troposphere relative to gas-phase only chemistry calculations …
Date:
October 1, 1991
Creator:
Kinnison, D.E. & Wuebbles, D.J.
Object Type:
Article
System:
The UNT Digital Library
PNL In Vivo Phantom Library Calibration Program
None
Date:
October 1, 1991
Creator:
Olsen, P. C.; Nichols, L. L.; Sisk, D. R. (Pacific Northwest Lab., Richland, WA (United States)) & Loesch, R. M. (USDOE, Washington, DC (United States))
Object Type:
Article
System:
The UNT Digital Library
Ion-optical studies for improved ion transmission in multistage isotope-ratio mass spectrometers
Theoretical and experimental ion-optical studies of multistage isotope-ratio mass spectrometers were conducted to determine what improvement in ion transmission efficiency might be attainable through design changes. The computer program GIOS (General Ion Optical Systems) was used to perform theoretical calculations of focusing properties and ion transmission efficiency. Actual transmission through multiple-sector instruments was determined from measurements of the ion beam vertical profile at the focus of each stage. For existing mass spectrometers with tandem magnets of normal geometry, our studies determined a feasible design change that significantly increases ion transmission through the analyzer. The use of a cylindrical einzel lens or an electrostatic quadrupole lens near the focal point between the magnets provides vertical focusing of the ion beam to achieve the improved transmission. We also established a new mass spectrometer design that give 100% transmission through tandem magnetic analyzers and through a third-stage electrostatic analyzer without the use of an intermediate focusing lens. Non-normal magnetic field boundaries provide ion beam focusing in the vertical plant to achieve this complete transmission. 19 refs., 27 figs., 3 tabs.
Date:
October 1, 1991
Creator:
Stoffels, J.J. (Pacific Northwest Lab., Richland, WA (United States)) & Laue, H.J. (Purdue Univ., Lafayette, IN (United States))
Object Type:
Report
System:
The UNT Digital Library
Electric power monthly, October 1991. [CONTAINS GLOSSARY]
This publication provides monthly statistics at the national, Census division, and State levels for net generation, fuel consumption, fuel stocks, quantity and quality of fuel, cost of fuel, electricity sales, revenue, and average revenue per kilowatthour of electricity sold. Data on net generation, fuel consumption, fuel stocks, quantity and cost of fuel are also displayed at the North American Electric Reliability Council (NERC) region level. Additionally, statistics at the company and plant level are published in the EPM on capability of new plants, net generation, fuel consumption, fuel stocks, quantity and quality of fuel, and cost of fuel. 4 figs., 63 tabs.
Date:
October 11, 1991
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
The Advanced Light Source U8 beam line, 20--300 eV
The U8 is a beam line under construction at the Advanced Light Source (ALS). The beam line will be described along with calculations of its performance and its current status. An 8 cm period undulator is followed by two spherical collecting mirrors, an entrance slit, spherical gratings having a 15{degree} deviation angle, a moveable exit slit, and refocusing and branching mirrors. Internal water cooling is provided to the metal M1 and M2 mirrors as well as to the gratings. Calculations have been made of both the flux output and the resolution over its photon energy range of 20--300 eV. The design goal was to achieve high intensity, 10{sup 12} photons/sec, at a high resolving power of 10,000. The U8 Participating Research Team (PRT) is planning experiments involving the photoelectron spectroscopy of gaseous atoms and molecules, the spectroscopy of ions and actinide spectroscopy.
Date:
October 1, 1991
Creator:
Heimann, P.; Warwick, T.; Howells, M.; McKinney, W.; Digennaro, D.; Gee, B. et al.
Object Type:
Article
System:
The UNT Digital Library
Petroleum marketing monthly, October 1991. [Contains glossary]
This report is designed to give information and statistical data about a variety of crude oils and refined petroleum products. The publication provides statistics on crude oil costs and refined petroleum products sales for use by industry, government, private sector analysts, educational institutions, and consumers. Data on crude oil include the domestic first purchase price, the f.o.b. and landed cost of imported crude oil, and the refiner's acquisition cost of crude oil. Sales data for motor gasoline, distillates, residuals, aviation fuels, kerosene, and propane are presented. 12 figs., 55 tabs.
Date:
October 10, 1991
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Manual for COMSYN: A orbit integration code for the study of beam dynamics in compact synchrotrons
COMSYN is a numerical integration code which is written for the study and design of the compact synchrotrons. An improved 4th-order Runge-Kutta method is used in COMSYN to integrate the exact equations of motion in a rectangular coordinate system. The magnetic field components of the dipole B{sub x}, B{sub y} and B{sub z} can be obtained from either measurement or directly computed data (MAGNUS, TOSCA). A spline interpolation method is then used to get the field value at the particle position. For standard quadrupole and sextupole, the analytical expression is employed to compute its field distribution.
Date:
October 1, 1991
Creator:
Huang, Y.
Object Type:
Report
System:
The UNT Digital Library
[Letter from Don R. Roberts to Bill McCarter and Jack Davis, October 8, 1991]
Photocopy of a letter from Don R. Roberts, Superintendent of Fort Worth ISD, to Bill McCarter and Jack Davis, co-directors of North Texas Institute for Educators on the Visual Arts, in regards to FWISD's commitment to NTIEVA. Their Associate Director, Beverly Fletcher, will contribute at least 10% of her time during the 1991 - 1992 calendar year to activities related to staff development and implementation efforts. Along with thirteen art specialists devoting a substantial amount of time toward the DBAE program.
Date:
October 8, 1991
Creator:
Roberts, Don R.
Object Type:
Letter
System:
The UNT Digital Library
[Letter draft from Hurst-Euless-Bedford ISD to Bill McCarter and Jack Davis, October 1991]
Photocopy of a letter draft to Bill McCarter and Jack Davis, co-directors of North Texas Institute for Educators on the Visual Arts, in regards to Hurst-Euless-Bedford Independent School District's commitment to the NTIEVA program and that their Site Coordinator, Jan Schronk, will contribute a certain percentage of time during the 1992 calendar. This letter draft is created by NTIEVA and sent to their consortium districts to be filled out by the coordinator and asked to be sent back with the proper filled information.
Date:
October 1991
Creator:
unknown
Object Type:
Letter
System:
The UNT Digital Library
[Letter from Bill McCarter and Nancy Reynolds to Trustee of the Marcus Foundation, October 27, 1994]
Photocopy of a letter from Bill McCarter and Nancy Reynolds, North Texas Institute for Educators on the Visual Arts, to the Trustees of the Edward and Betty Marcus Foundation. In regards to a project proposed by the San Antonio Museum of Art, SAMA to development a series of art reproductions and presentation for a summer institute to train teachers. McCarter and Reynolds write that they have worked with SAMA since the museum educators attended a Marcus-funded advocacy workshop and believe that their proposal is consistent and similar to NTIEVA's efforts and support their proposal.
Date:
October 27, 1994
Creator:
McCarter, William & Reynolds, Nancy
Object Type:
Letter
System:
The UNT Digital Library