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United States Department of Energy Oak Ridge Operations

Works: 2,007 works in 2,213 publications in 1 language and 8,637 library holdings
Roles: Researcher
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Most widely held works by United States
Northeast Regional Biomass Energy Program( )

2 editions published in 1992 in English and held by 0 WorldCat member libraries worldwide

The Northeast Regional Biomass Program (NRBP) is entering its ninth year of operation. The management and the objectives have virtually remained unchanged and are stated as follows. The program conducted by NRBP has three basic features: (1) a state grant component that provides funds (with a 50 percent matching requirement) to each of the states in the region to strengthen and integrate the work of state agencies involved in biomass energy; (2) a series of technical reports and studies in areas that have been identified as being of critical importance to the development of biomass energy in the region; and (3) a continuous long range planning component with heavy private sector involvement that helps to identify activities necessary to spur greater development and use of biomass energy in the Northeast
Activity composition relationships in silicate melts. Final report( )

2 editions published in 1990 in English and held by 0 WorldCat member libraries worldwide

Equipment progress include furnace construction and electron microprobe installation. The following studies are underway: phase equilibria along basalt-rhyolite mixing line (olivine crystallization from natural silicic andensites, distribution of Fe and Mg between olivine and liquid, dist. of Ca and Na between plagioclase and liquid), enthalpy-composition relations in magmas (bulk heat capacity of alkali basalt), density model for magma ascent and contamination, thermobarometry in igneous systems (olivine/plagioclase phenocryst growth in Quat. basalt), high-pressure phase equilibria of alkali basalt, basalt-quartz mixing experiments, phase equilibria of East African basalts, and granitic minerals in mafic magma. (DLC)
Measurements of scattering processes in negative ion-atom collisions( )

3 editions published between 1987 and 1993 in English and held by 0 WorldCat member libraries worldwide

In this paper, the non-exponential decay is analyzed with the help of simple computer experiments performed by T. Petrosky, simulating classical radiation damping. The non-exponential decay is studied and shown to depend on the preparation of the system. However, whatever the initial preparation, the system reaches the decay predicted by classical radiation theory after a short time we call the Zeno's time. The similitude of Petrosky's results with computer experiments for the approach to equilibrium in many-body systems is emphasized. However, while there one deals with times which are multiple of the relaxation time, the irreversibility manifest in radiation theory occurs always over a much shorter time scale, the Zeno's time. In atomic systems, this would be a time order of 10/sup /minus/18/ seconds. These results are of great interest for the understanding of the microscopic mechanism of radiation. Let us consider a charged oscillator. In a first stage, this oscillator has to produce the field oscillators to which it may transfer energy through the usual resonance mechanism. Radiation appears therefore as a kind of non linear autocatalytic process, involving a self-organization mechanism. The behavior during the Zeno period can be explained easily in terms of subdynamics as introduced by the Brussel's group. We see that there is no transition from reversibility to irreversibility. Irreversible processes start at the very moment at which the system is prepared. It is important to stress that an unstable particle is itself the result of irreversible processes. As a result, an unstable particle (or an excited atomic state) can no more be described in terms of wave functions, as irreversible processes are not included in Schroedinger's equation. 14 refs., 3 figs
Magnetic surfaces in a steady-state tokamak( )

2 editions published in 1992 in English and held by 0 WorldCat member libraries worldwide

We study a toroidal plasma in a tokamak with externally given toroidal and poloidal magnetic fields as well as self-consistently interacting internal currents. The unperturbed magnetic surfaces are described by the well-known nonlinear ''standard map.'' When the magnetic field is allowed to carry an internal current, the self-interaction of these currents disturbs the integrity of the magnetic surfaces. We carry out a computational study of the effects of the interacting internal current filaments, measuring the diffusion of field lines from the unperturbed surfaces, and find the self-interaction to be a significant effect which always serves to increase diffusion. Perfect surfaces are difficult to maintain even when magnetic islands do not overlap. Diffusion from the current interaction dominates when current fluctuations reach (approximately) 10% of the applied field
Domain wall formation in late-time phase transitions( )

4 editions published between 1992 and 1996 in English and held by 0 WorldCat member libraries worldwide

The authors extend the model of string as a polymer of string bits to the case of superstring. They mainly concentrate on type II-B superstring, with some discussion of the obstacles presented by not II-B superstring, together with possible strategies for surmounting them. As with previous work on bosonic string work within the light-cone gauge. The bit model possesses a good deal less symmetry than the continuous string theory. For one thing, the bit model is formulated as a Galilei invariant theory in (D - 2) + 1 dimensional space-time. This means that Poincare invariance is reduced to the Galilei subgroup in D - 2 space dimensions. Naturally the supersymmetry present in the bit model is likewise dramatically reduced. Continuous string can arise in the bit models with the formation of infinitely long polymers of string bits. Under the right circumstances (at the critical dimension) these polymers can behave as string moving in D dimensional space-time enjoying the full N = 2 Poincare supersymmetric dynamics of type II-B superstring
A tumbling top-quark condensate model( )

3 editions published between 1992 and 1996 in English and held by 0 WorldCat member libraries worldwide

Discrete and global symmetries play an essential role in many extensions of the Standard Model, for example, to preserve the proton lifetime, to prevent flavor changing neutral currents, etc. An important question is how can such symmetries survive in a theory of quantum gravity, like superstring theory. In a specific string model the author illustrates how local discrete symmetries may arise in string models and play an important role in preventing fast proton decay and flavor changing neutral currents. The local discrete symmetry arises due to the breaking of the non-Abelian gauge symmetries by Wilson lines in the superstring models and forbids, for example dimension five operators which mediate rapid proton decay, to all orders of nonrenormalizable terms. In the context of models of unification of the gauge and gravitational interactions, it is precisely this type of local discrete symmetries that must be found in order to insure that a given model is not in conflict with experimental observations
Zircons and fluids an experimental investigation with applications for radioactive waste disposal. Hydrothermal stability of zircons( )

2 editions published in 1991 in English and held by 0 WorldCat member libraries worldwide

The long-term stability of nuclear waste forms or barriers is related to changes in physical properties of the material induced through radiation damage and subsequent changes in solubility. Investigations conducted by us on natural zircons (ZrSiO₄) supports a positive correlation between level of alpha damage and fluid composition to enhanced levels of corrosion. New data are presented on the nature and rate of the solution process. We also present data on our continuing efforts to synthesize and characterize both pure ZrSiO₄ and doped with U, Th, Hf, Dy and P
Development of Technologies for a High Efficiency, Very Low Emission, Diesel Engine for Light Trucks and Sport Utility Vehicles( )

2 editions published between 1997 and 2005 in English and held by 0 WorldCat member libraries worldwide

Cummins Inc., in partnership with the Department of Energy, has developed technology for a new highly efficient, very low emission, diesel engine for light trucks and sport utility vehicles. This work began in April 1997, and started with very aggressive goals for vehicles in the 5751 to 8500 pound GCW weight class. The primary program goals were as follows: (1) EMISSIONS -- NOx = 0.50 g/mi; PM = 0.05 g/mi; CO = 2.8 g/mi; and NMHC = 0.07 g/mi. California decided to issue new and even tougher LEV II light truck regulations late in 1999. EPA also issued its lower Tier 2 regulations late in 2000. The net result was that the targets for this diesel engine project were lowered, and these goals were eventually modified by the publication of Federal Tier 2 emission standards early in 2000 to the following: NOx = 0.07 g/mi; and PM = 0.01 g/mi. (2) FUEL ECONOMY -- The fuel economy goal was 50 percent MPG improvement (combined city/highway) over the 1997 gasoline powered light truck or sport utility vehicle in the vehicle class for which this diesel engine is being designed to replace. The goal for fuel economy remained at 50 percent MPG improvement, even with the emissions goal revisions. (3) COOPERATIVE DEVELOPMENT -- Regular design reviews of the engine program will be conducted with a vehicle manufacturer to insure that the concepts and design specifics are commercially feasible. (DaimlerChrysler has provided Cummins with this design review input.) Cummins has essentially completed a demonstration of proof-of-principle for a diesel engine platform using advanced combustion and fuel system technologies. Cummins reported very early progress in this project, evidence that new diesel engine technology had been developed that demonstrated the feasibility of the above emissions goals. Emissions levels of NOx = 0.4 g/mi and PM = 0.06 g/mi were demonstrated for a 5250 lb. test weight vehicle with passive aftertreatment only. These results were achieved using the full chassis dynamometer FTP-75 test procedure that allowed compliance with the Tier 2 Interim Bin 10 Standards and would apply to vehicles in MY2004 through MY2007 timeframe. In further technology development with active aftertreatment management, Cummins has been able to report that the emissions goals for the Tier 2 Bin 5 standards were met on an engine running the full FTP-75 test procedure. The fuel economy on the chassis tests was measured at over 59 percent MPG improvement over the gasoline engines that are offered in typical SUVs and light trucks. The above demonstration used only in-cylinder fueling for management of the aftertreatment system
Radiation-induced micrencephaly in guinea pigs( )

3 editions published between 1991 and 1992 in English and held by 0 WorldCat member libraries worldwide

The effect of x rays on brain weight of guinea pig pups at birth was studied for 21-day old embroys exposed in utero to doses of 75 and 100 mGy. When compared to controls and when corrected for body weight, gestation time, litter size, sex, and examiner differences the brains of irradiated pups weighed approximately 46 mg less than those of controls (p<0.001) for the 75-mGy group and about 55 mg less for the 100-mGy group. Brains of females weighed 51 mg less than those of males of the same body weight. Dam weight and caging conditions had no observed effect on brain weight
Some simple criteria for gauged R-parity( )

2 editions published in 1992 in English and held by 0 WorldCat member libraries worldwide

Some simple conditions which are sufficient to guarantee that R- parity survives as an unbroken gauged discrete subgroup of the continuous gauge symmetry in certain supersymmetric extensions of the standard model are presented
A quenched c 1 critical matrix model( )

2 editions published in 1990 in English and held by 0 WorldCat member libraries worldwide

We study a variant of the Penner-Distler-Vafa model, proposed as a c = 1 quantum gravity: 'quenched' matrix model with logarithmic potential. The model is exactly soluble, and exhibits a two-cut branching as observed in multicritical unitary matrix models and multicut Hermitian matrix models. Using analytic continuation of the power in the conventional polynomial potential, we also show that both the Penner-Distler-Vafa model and our 'quenched' matrix model satisfy Virasoro algebra constraints
Fermilab E791( )

2 editions published in 1992 in English and held by 0 WorldCat member libraries worldwide

Fermilab E791, a very high statistics charm particle experiment, recently completed its data taking at Fermilab's Tagged Photon Laboratory. Over 20 billionevents were recorded through a loose transverse energy trigger and written to 8mm tape in the 1991--92 fixed target run at Fermilab. This unprecedented data sample containing charm is being analysis on many-thousand MIP RISC computing farms set up at sites in the collaboration. A glimpse of the data taking and analysis effort is presented. We also show some preliminary results for common charm decay modes. Our present analysis indicates a very rich yield of over 200K reconstructed charm decays
Committee on Atomic, Molecular, and Optical Sciences (CAMOS). Technical progress report, [February 1, 1991--January 31, 1992]( )

3 editions published in 1992 in English and held by 0 WorldCat member libraries worldwide

The Committee on Atomic, Molecular, and Optical Sciences is a standing committee under the auspices of the Board on Physics and Astronomy, Commission on Physical Sciences, Mathematics, and Applications of the National Academy of Sciences -- National Research Council. The atomic, molecular, and optical (AMO) sciences represent a broad and diverse field in which much of the research is carried out by small groups. These groups generally have not operated in concert with each other and, prior to the establishment of CAMOS, there was no single committee or organization that accepted the responsibility of monitoring the continuing development and assessing the general public health of the field as a whole. CAMOS has accepted this responsibility and currently provides a focus for the AMO community that is unique and essential. The membership of CAMOS is drawn from research laboratories in universities, industry, and government. Areas of expertise on the committee include atomic physics, molecular science, and optics. A special effort has been made to include a balanced representation from the three subfields. (A roster is attached.) CAMOS has conducted a number of studies related to the health of atomic and molecular science and is well prepared to response to requests for studies on specific issues. This report brief reviews the committee work of progress
Self shielding of surfaces irradiated by intense energy fluxes. Final report( )

2 editions published in 1991 in English and held by 0 WorldCat member libraries worldwide

This dissertation will outline a direct methods of temperature, density, composition, and velocity measurement which should be widely applicable to railgun systems. The measurements demonstrated here should prove usefull basis for further studies of plasma/target interaction
Magnetic reconnection at stressed x-type neutral points( )

2 editions published in 1992 in English and held by 0 WorldCat member libraries worldwide

The reconnection and relaxation of two-dimensional stressed (non-potential) x-type neutral point magnetic fields are studied via solution of the nonlinear resistive 2-D MHD equations and by analytical solution of the linear eigenvalue problem. The linear dispersion relation was generalized for azimuthally nonsymmetric perturbations, and have found that for modes with azimuthal mode numbers m> 0, the relaxation can occur at a rate faster than that for n = m = 0, where n is the radial ''quantum'' number. One finds that for nearly azimuthally symmetric magnetic perturbations that are zero at the boundary; i.e. the ''frozen-in'' (sometimes called ''fine-tied'') boundary conditions, the fields relax incompressibly and nonlinearly to the unstressed x-type neutral point at a rate close to that predicted by linear theory. Also, fully compressible nonlinear MHD simulations have been performed, which show that the interaction between the plasma flow velocity and the magnetic field is the important physical effect, while the inclusion of thermodynamics does not affect the evolution considerably. A Lyapunov functional for the nonlinear incompressible 2-D resistive MHD equations is derived to show that the current-free x-point configuration is a global equilibrium to which general initial conditions relax
Network based high performance concurrent computing( )

2 editions published in 1991 in English and held by 0 WorldCat member libraries worldwide

The overall objectives of this project are to investigate research issues pertaining to programming tools and efficiency issues in network based concurrent computing systems. The basis for these efforts is the PVM project that evolved during my visits to Oak Ridge Laboratories under the DOE Faculty Research Participation program; I continue to collaborate with researchers at Oak Ridge on some portions of the project
Kinetics and mechanisms of key elementary processes of importance to high temperature combustion chemistry. [Final report, June 1, 1985--August 31, 1989]( )

2 editions published in 1989 in English and held by 0 WorldCat member libraries worldwide

We have investigated the kinetics and mechanisms numerous reactions involving many key reactive combustion species: CH₂O, CH₃O, CH, NO, NO₂, CH₃OH, C₂H₅OH, i-C₃H--OH, t-C₄H₉OH, C₆H₅, C₅O and C₆H₅O and C₆H₆, among others. A total of 24 reactive systems have been studied
X-ray scattering studies of non-equilibrium ordering processes. Progress report, November 1, 1989--October 31, 1992( )

4 editions published between 1991 and 1992 in English and held by 0 WorldCat member libraries worldwide

We report on the progress of the project entitled ''X-ray Scattering Studies of Non-Equilibrium Ordering Processes.'' The past year has seen continued progress in the study of kinetic effects in metallic binary alloys and polymers. In addition, work has begun on a low dimensional CDW system: blue bronze. A sample chamber has been constructed to perform small angle neutron scattering measurements on a model quantum system with phase separation: solid He3/He4. Work is continuing on magnetic systems. Planned future experiments include an investigation of crystallization in Rubidium
On neutral plasma oscillations( )

3 editions published between 1992 and 1993 in English and held by 0 WorldCat member libraries worldwide

We examine the conditions for the existence of spectrally stable neutral modes in a Vlasov-Poisson plasma and show that for stable equilibria of systems that have unbounded spatial domain, the only possible neutral modes are those with phase velocities that correspond to stationary inflection points of the equilibrium distribution function. It is seen that these neutral modes can possess positive or negative free energy
Nuclear structure from radioactive decay. Annual progress report( )

2 editions published in 1992 in English and held by 0 WorldCat member libraries worldwide

The most important aspect of the wind-up of UNISOR-based research is completion of student theses. Analysis is proceeding on extensive studies in the neutron-deficient rare earth isotopes with N <82 and the neutron-deficient region below Z = 82. These studies address the onset of deformation in the N <82, Z> 50 open shell region and shape coexistence in the N (approximately) 104, Z (less-than or equal to) 82 region, respectively. The main ongoing topics are shape coexistence in nuclei and the microscopic structure of collective motion in nuclei from a phenomenological point of view. New topics this year focus on the structure of nuclei near the N = Z line. Two topics have been chosen for detailed study: shape coexistence and electric monopole transition strengths
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