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Chaos: Chto Delat

Description: Provided is a brief overview of the current status of the field of deterministic ''chaos'', stressing its interrelations and applications to other fields and suggesting a number of important open problems for future study.
Date: January 1, 1987
Creator: Campbell, D.
Partner: UNT Libraries Government Documents Department

Application of pressurized ion exchange to separations of transplutonium elements

Description: High-pressure ion exchange chromatography, used first for nucleic acid separations, was applied to the production of the heavier actinides, particularly the transcurium elements. Its use at the TRU plant is described. Future developments are considered briefly. (DLC)
Date: January 1, 1980
Creator: Campbell, D.O.
Partner: UNT Libraries Government Documents Department

Field theoretic extensions of TDHF techniques

Description: A possible extension of time-dependent Hartree-Fock (TDHF) techniques to relativistic quantum field theories is discussed. A set of extended TDHF equations which incorporates naturally relativistic kinematics and treats the mesons, the effects of which are in ordinary TDHF represented by a nonindependent mean field, as independent dynamical degrees of freedom. In a simple model field theory in one space and one time dimension the extended TDHF equations are solved analytically for certain static field configurations and numerically for the time-dependent scattering configuration. Qualitative features of the scattering solutions as observed in preliminary numerical studies are discussed, and the conclusion is reached by mentioning a number of problems for further research. 22 references.
Date: January 1, 1979
Creator: Campbell, D.K.
Partner: UNT Libraries Government Documents Department

Review of single transient oscillographic recorders with gigahertz bandwidth

Description: In laser driven inertial confinement fusion research, at Livermore, we are diagnosing many phenomena that occur in a time frame that exceeds the capabilities of even the most advanced, present day oscillographic recording instruments. Many of the by-products of the interaction between the laser beam and fuel pellet are monitored to determine the specifics of the fusion process. By the use of appropriate detectors, we convert the information contained in the radiated by-products to electrical signals which are recorded on high bandwidth oscillographic recorders. Our present range of recording capabilities for one x-ray diagnostic measurement in use at Livermore is shown. A commonly used configuration consists of an XRD-31 x-ray detector connected to a direct access Tektronix R7912 transient digitizer using 1/2 in. diameter air dielectric coaxial cable. This configuration gives a system fwhm of approximately 335 ps. Our premier configuration, on the other hand, consists of an improved response detector and a French Thomson-CSF TSN-660 oscilloscope with a shorter length of coaxial cable (typically 20 feet). The system fwhm in this case is less than 120 ps which is our fastest oscillographic recording system at the present time.
Date: October 20, 1982
Creator: Campbell, D.E.
Partner: UNT Libraries Government Documents Department

Electronics of the target diagnostics system for the Shiva Laser Fusion Facility

Description: The organizing philosophy and components of a target diagnostics data acquisition system designed and implemented at the Lawrence Livermore Laboratory (LLL) Shiva Laser Fusion Facility are described. Several features of the system are unique: a central trigger distribution system, fiber optic communications, and fiber optics for the timing, trigger, and control and monitoring links. The system also uses CAMAC instrumentation, transient digitizers, oscilloscopes, and LLL-designed modules and packages, as well as single-point grounding of each diagnostic installation. Distributed instrumentation packages provide instrumentation flexibility and analog-to-digital conversion as close to each diagnostic sensor as practical.
Date: July 26, 1978
Creator: Campbell, D. & Severyn, J.
Partner: UNT Libraries Government Documents Department

Solitons and polarons in quasi-one dimensional conducting polymers and related materials

Description: In recent years it has become increasingly appreciated that fundamentally nonlinear excitations - solitons - play an essential role in an incredible variety of natural systems. These solitons, which frequently exhibit remarkable stability under interactions and perturbations, often dominate the transport, response, or structural properties of the systems in which they occur. In this article, we present an introduction to the solitons that occur in quasi-one-dimensional conducting polymers (synmetals) and related systems. The relevance of this subject to molecular electronic devices is twofold. First, many of these materials have molecular structures similar to possible prototype molecular switches. Second, to understand in detail how a molecular electronic device could work, it is essential to have a broad perspective on the nature of possible excitations in a variety of natural and synthetic molecular materials. 51 references.
Date: January 1, 1983
Creator: Campbell, D.K.
Partner: UNT Libraries Government Documents Department

Diagnostic measurements related to laser driven inertial confinement fusion

Description: Scientists at the Lawrence Livermore Laboratory have been conducting laser driven inertial confinement fusion experiments for over five years. The first proof of the thermonuclear burn came at the Janus target irradiation facility in the spring of 1975. Since that time three succeedingly higher energy facilities have been constructed at Livermore, Cyclops, Argus and Shiva, where increased fusion efficiency has been demonstrated. A new facility, called Nova, is now in the construction phase and we are hopeful that scientific break even (energy released compared to incident laser energy on target) will be demonstrated here in early 1980's. Projected progress of the Livermore program is shown.
Date: September 11, 1979
Creator: Campbell, D.E.
Partner: UNT Libraries Government Documents Department

3-D structures and intrinsic defects in trans-polyacetylene

Description: We report first-principles local-density functional pseudopotential calculations of static and dynamic electronic structure properties of crystalline 3-D trans--(CH)/sub x/. We find a broken symmetry ground state of P2/sub 1//a symmetry with in-phase dimerizations. Using a Green's function technique, we show that the 3-D character of the electronic band edge states strongly suppresses self-trapping, destabilizing polarons and possibly bipolarons as well in perfectly ordered 3-D trans--(CH)/sub x/. 26 refs.
Date: January 1, 1989
Creator: Vogl, P. & Campbell, D.K.
Partner: UNT Libraries Government Documents Department

Bond alternation in the infinite polyene: effect of long range Coulomb interactions

Description: We investigate the effects of long-range Coulomb interactions on bond and site dimerizations in a one-dimensional half-filled band. It is shown that the ground state broken symmetry is determined by two sharp inequalities involving the Coulomb parameters. Broken symmetry with periodicity 2k/sub F/ is guaranteed only if the first inequality (downward convexity of the intersite potential) is obeyed, while the second inequality gives the phase boundary between the bond-dimerized and site-dimerized phases. Application of these inequalities to the Pariser-Parr-Pople model for linear polyenes shows that the infinite polyene has enhanced bond alternation for both Ohno and Mataga-Nishimoto parametrizations of the intersite Coulomb terms. The possible role of distant neighbor interactions in photogeneration experiments is discussed. 26 refs., 3 figs.
Date: January 1, 1985
Creator: Mazumdar, S. & Campbell, D.K.
Partner: UNT Libraries Government Documents Department

PROCESSING OF MOLTEN SALT POWER REACTOR FUEL

Description: ABS> Fuel reprocessing methods are being investigated for molten salt nuclear reactors which use LiF--BeF/sub 2/ salt as a solvent for UF/sub 4/ and ThF/sub 4/. A liquid HF dissolution procedure coupled with fluorination has been developed for recovery of the uranium and LiF- BeF/sub 2/ solvent salt which is highly enriched in Li/sup 7/. The recovered salt is decontaminated in the process from the major reactor poisons; namely, rare earths and neptunium. A brief investigation of alternate methods, including oxide precipitation, partial freezing, and metal reduction, indicated that such methods may give some separation of the solvent salt from reactor poisons, but they do not appear to be sufficiently quantitative for a simple processing operation. Solubilities of LiF and BeF/sub 2/ in aqueous 70t0 100% HF are presented. The BeF/sub 2/ solubility is appreciably increased in the presence of water and large amounts of LiF. Salt solubilities of 150 g/liter are attainable. Tracer experiments indicate that rare earth solubilities, relative to LiF-- BeF/sub 2/ solvent salt solubility, increase from about 10/sup -4/ mole% in 98% HF to 0.003 mole% in 80% HF. Fluorination of uranium from LiF--BeF/sub 2/ salt was demonstrated. This appears feasible also for the recovery of the relatively small ccncentration of uranium produced in the LiF- BeF/sub 2/ThF/sub 4/ blanket. A proposed chemical flowsheet is presented on the basis of this exploratory work as applied to the semicontinuous processing of a 600 Mw power reactor. (auth)
Date: April 1, 1959
Creator: Campbell, D.O. & Cathers, G.I.
Partner: UNT Libraries Government Documents Department

Coulomb correlation effects in quasi-one-dimensional conductors

Description: Recent results on the role of electron-electron (e-e) interactions - ''correlation effects'' - in quasi-one-dimensional conductors are reviewed. Within the Peierls-Hubbard model, the consequences of short range (on-site U and nearest neighbor V) e-e interactions for ground state properties, nonlinear excitations, and optical absorption are examined. Techniques include quantum Monte Carlo and weak and strong coupling perturbative arguments. 26 refs., 2 figs.
Date: January 1, 1986
Creator: Campbell, D.K.; Baeriswyl, D. & Mazumdar, S.
Partner: UNT Libraries Government Documents Department

Characterization of solids in the Three Mile Island Unit 2 Reactor defueling water: Addendum

Description: Shortly after ORNL/TM-10362 was issued, it was discovered that a series of 31 figures had been inadvertently omitted. These figures, which consist of scanning electron microscope (SEM) photographs and energy-dispersive X-ray fluorescence scans, provide significant information about the results obtained in the tests performed with water sample W3. This Addendum includes these figures. Details of and comments on the SEM photographs may be found in ORNL/TM-10362.
Date: March 1, 1988
Creator: Campbell, D.O.
Partner: UNT Libraries Government Documents Department

Chaos and order in non-integrable model field theories

Description: We illustrate the presence of chaos and order in non-integrable, classical field theories, which we view as many-degree-of-freedom Hamiltonian nonlinear dynamical systems. For definiteness, we focus on the {chi}{sup 4} theory and compare and contrast it with the celebrated integrable sine-Gordon equation. We introduce and investigate two specific problems: the interactions of solitary kink''-like waves in non-integrable theories; and the existence of stable breather'' solutions -- spatially-localized, time-periodic nonlinear waves -- in the {chi}{sup 4} theory. For the former problem we review the rather well developed understanding, based on a combination of computational simulations and heuristic analytic models, of the presence of a sequence of resonances in the kink-antikink interactions as a function of the relative velocity of the interaction. For the latter problem we discuss first the case of the continuum {chi}{sup 4} theory. We discuss the multiple-scale asymptotic perturbation theory arguments which first suggested the existence of {chi}{sup 4} breathers, then the subsequent discovery of terms beyond-all-orders'' in the perturbation expansion which destroy the putative breather, and finally, the recent rigorous proofs of the non-existence of breathers in the continuum theory. We then present some very recent numerical results on the existence of breathers in discrete {chi}{sup 4} theories which show an intricate interweaving of stable and unstable breather solutions on finite discrete lattices. We develop a heuristic theoretical explanation of the regions of stability and instability.
Date: January 1, 1989
Creator: Campbell, D.K. & Peyrard, M.
Partner: UNT Libraries Government Documents Department

Characterization of solids in the Three Mile Island Unit 2 reactor defueling water

Description: Because of the impact of poor water clarity on defueling operations at the Three Mile Island Unit 2 Nuclear Power Station, a study was undertaken to characterize suspended particulates in the reactor defueling water. The examination included cascade filtration through Nuclepore filters of progressively smaller pore sizes, using three water samples obtained at different times and after varying degrees of clarification. The solids collected on the filters were examined with a scanning electron microscope and analyzed with energy-dispersive x-ray fluorescence. A wide variety of solids was observed, and 26 elements were detected. These included all the materials expected from the reactor system (uranium, zirconium, silver, cadmium, indium, iron, chromium, and nickel), chemicals and zeolites used to decontaminate the water (aluminum, silicon, sodium), common impurities (potassium, chlorine, sulfur, magnesium, calcium, and others), as well as some unexpected metals (molybdenum, manganese, bromine, and lead). There was also evidence for the presence of organic material. A diverse assortment of particles with widely varying surface properties was found to be present.
Date: December 1, 1987
Creator: Campbell, D. O.
Partner: UNT Libraries Government Documents Department

Improved 50 ps response x-ray detector with optical applications

Description: We have improved the impulse response characteristics of the LLNL 50 ps detector significantly. The detector has also been improved mechanically to permit much greater ease of assembly and repair. We are investigating modified versions of this design for optical applications. The detector was developed to complement the recording capability of our Thomson-CSF 4 GHz oscilloscopes in laser driven ICF fusion experiments research.
Date: September 30, 1981
Creator: Campbell, D.; Tirsell, G. & Laird, W.
Partner: UNT Libraries Government Documents Department

Scale inhibition in geothermal operations: experiments with Dequest 2060 phosphonate in Republic's East Mesa Field

Description: Two calcium carbonate (CaCO/sub 3/) scale inhibition tests have been performed at East Mesa wells number 16-29 and number 56-30. The first test at well number 16-29 could not be finished due to downhole pump problems. However, two inhibitor concentration runs were completed and a third run started before the pump failed. A follow-up test at well number 56-30 was completed according to the original plan. Typical power plant conditions (i.e., pressure and temperature drops, flow conditions) were simulated by using test loops (pipe diameters of eight inches at well number 16-29 and twelve inches at well number 56-30) and field separators. Untreated East Mesa brine exhibits a calcium carbonate scale tendency as soon as the pressure is dropped below 75 psig. The uninhibited brine from well number 16-29 formed a maximum scale thickness of 0.5 inch in an eight inch ID pipe after a 92.75 hour test run at an average production rate of 375,000 lb/hr. The brine from well number 56-30 formed a maximum scale thickness of 1.25 inches in a twelve inch ID pipe after a 104 hour test run at an average production rate of 722,000 lb/hr. The principal conclusions of this test work are listed.
Date: June 1, 1979
Creator: Vetter, O.J. & Campbell, D.A.
Partner: UNT Libraries Government Documents Department

Electron-electron interaction effects in quasi-one-dimensional conducting polymers and related systems

Description: We review recent results on the role of electron-electron (e-e) interactions in quasi-one-dimensional conducting polymers and related systems. Within the Peierls-Hubbard model, the effects of both short-range (on-site U and nearest neighbor V/sub 1/) and long-range (V/sub j/, jgreater than or equal to 2) are examined, the former using quantum Monte Carlo and the latter with exact diagonalization of finite size systems and analytic arguments. We also discuss optical absorption properties in the presence of electronic correlation, focusing on the weak and strong coupling limits.
Date: January 1, 1986
Creator: Campbell, D.K.; Baeriswyl, D. & Mazumdar, S.
Partner: UNT Libraries Government Documents Department

Automation of a cryogenic facility by commercial process-control computer

Description: To insure that Brookhaven's superconducting magnets are reliable and their field quality meets accelerator requirements, each magnet is pre-tested at operating conditions after construction. MAGCOOL, the production magnet test facility, was designed to perform these tests, having the capacity to test ten magnets per five day week. This paper describes the control aspects of MAGCOOL and the advantages afforded the designers by the implementation of a commercial process control computer system.
Date: January 1, 1983
Creator: Sondericker, J.H.; Campbell, D. & Zantopp, D.
Partner: UNT Libraries Government Documents Department

Polarons in polyacetylene

Description: Recent theoretical studies of polyacetylene, (CH)/sub x/ have focused on kink-like solutions in the trans isomer. It is shown that the same theoretical models also predict polaron-like solutions in both cis- and trans-(CH)/sub x/. The explicit form of these polarons, their relation to kinks, possible implications for experiment, and open questions are discussed.
Date: January 1, 1981
Creator: Bishop, A.R. & Campbell, D.K.
Partner: UNT Libraries Government Documents Department