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Thermodynamics and electrodynamics of unusual narrow-gap semiconductors

Description: This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL) that has led to a fully funded DOE program to continue this work. The project was directed toward exploring the Ettingshausen effect, which is the direct extension of the familiar Peltier-effect refrigerator (the process used in popular coolers that run off automotive electrical power) in which a magnetic field is used to enhance refrigeration effects at temperatures well below room temperature. Such refrigeration processes are all-solid-state and are of potentially great commercial importance, but essentially no work has been done since the early 1970s. Using modern experimental and theoretical techniques, the authors have advanced the state-of-the-art significantly, laying the groundwork for commercial cryogenic solid-state refrigeration.
Date: December 1998
Creator: Migliori, A.; Darling, T. W.; Trugman, S. A.; Freibert, F.; Moshopoulou, E. & Sarrao, J. L.
Partner: UNT Libraries Government Documents Department

Light-fronts approach to electron-positron pair production in ultrarelativistic heavy-ion collisions

Description: The authors solve, in an ultrarelativistic limit, the time-dependent Dirac equation describing electron-positron pair production in peripheral relativistic heavy ion collisions using light front variables and a light-fronts representation, obtaining nonperturbative results for the free pair-creation amplitudes in the collider frame. Their result reproduces the result of second-order perturbation theory in the small charge limit while nonperturbative effects arise for realistic charges of the ions.
Date: March 1, 1998
Creator: Wells, J. C. & Segev, B.
Partner: UNT Libraries Government Documents Department

Microfluidic Engineering

Description: The ability to generate high pressures using electrokinetic pumping of liquid through porous media is reported. Pressures in excess of 8000 psi have been achieved using capillaries (< 100 {micro}m i.d.) packed with micron-size silica beads. A model is presented which accurately predicts absolute pressures, flowrates and power conversion efficiencies as well as the experimentally observed dependencies on pore size, applied electric field and electrical properties of the fluid. This phenomenon offers the possibility of creating a new class of microscale fluid devices, electrokinetic pumps and valves, where the performance improves with scale-down by taking advantage of microscale processes.
Date: December 1, 1998
Creator: Paul, Phillip H.
Partner: UNT Libraries Government Documents Department

From the Feynman-Schwinger representation to the non-perturbative relativistic bound state interaction

Description: The authors write the 4-point Green function in QCD in the Feynman-Schwinger representation and show that all the dynamical information are contained in the Wilson loop average. They work out the QED case in order to obtain the usual Bethe-Salpeter kernel. Finally they discuss the QCD case in the non-perturbative regime giving some insight in the nature of the interaction kernel.
Date: March 1, 1997
Creator: Brambilla, N. & Vairo, A.
Partner: UNT Libraries Government Documents Department

ELECTROKINETIC DENSIFICATION OF COAL FINES IN WASTE PONDS

Description: The objective of this research was to demonstrate that electrokinetics can be used to remove colloidal coal and mineral particles from coal-washing ponds and lakes without the addition of chemical additives such as salts and polymeric flocculants. The specific objectives were: Design and develop a scaleable electrophoresis apparatus to clarify suspensions of colloidal coal and clay particles; Demonstrate the separation process using polluted waste water from the coal-washing facilities at the coal-fired power plants in Centralia, WA; Develop a mathematical model of the process to predict the rate of clarification and the suspension electrical properties needed for scale up.
Date: December 18, 1999
Creator: Davis, E. James
Partner: UNT Libraries Government Documents Department

Feynman-Schwinder representation approach to nonperturbative physics

Description: The Feynman-Schwinger representation provides a convenient framework for the calculation of nonperturbative propagators. In this paper the authors first investigate an analytically solvable case, namely the scalar QED in 0+1 dimension. With this toy model they illustrate how the formalism works. The analytic result for the self energy is compared with the perturbative result. Next, using a {chi}{sup 2} {phi} interaction, they discuss the regularization of various divergences encountered in this formalism. The ultraviolet divergence, which is common in standard perturbative field theory applications, is removed by using a Pauli-Villars regularization. They show that the divergence associated with large values of Feynman-Schwinger parameter s is spurious and it can be avoided by using an imaginary Feynman parameter is.
Date: June 1, 1999
Creator: Savkli, C.; Tjon, J. & Gross, F.
Partner: UNT Libraries Government Documents Department

In situ soil remediation using electrokinetics

Description: Electrokinetics is emerging as a promising technology for in situ soil remediation. This technique is especially attractive for Superfund sites and government operations which contain large volumes of contaminated soil. The approach uses an applied electric field to induce transport of both radioactive and hazardous waste ions in soil. The transport mechanisms include electroosmosis, electromigration, and electrophoresis. The feasibility of using electrokinetics to move radioactive {sup 137}Cs and {sup 60}Co at the Hanford Site in Richland, Washington, is discussed. A closed cell is used to provide in situ measurements of {sup 137}Cs and {sup 60}Co movement in Hanford soil. Preliminary results of ionic movement, along with the corresponding current response, are presented.
Date: November 1, 1994
Creator: Buehler, M. F.; Surma, J. E. & Virden, J. W.
Partner: UNT Libraries Government Documents Department

The equation of motion of an electron

Description: We review the current status of understanding of the equation of motion of an electron. Classically, a consistent, linearized theory exists for an electron of finite extent, as long as the size of the electron is larger than the classical electron radius. Nonrelativistic quantum mechanics seems to offer a fine theory even in the point particle limit. Although there is as yet no convincing calculation, it is probable that a quantum electrodynamical result will be at least as well-behaved as is the nonrelativistic quantum mechanical results. {copyright} {ital 1999 American Institute of Physics.}
Date: July 1, 1999
Creator: Kim, K. & Sessler, A.M.
Partner: UNT Libraries Government Documents Department

Effective meson-meson interaction in 2+1 dimensional lattice QED

Description: A definition of an effective meson-meson interaction adapted to the framework of a lattice simulation is presented. Results, based on a truncated momentum-space 4-point time correlation matrix, and preliminary data from a complementary coordinate-space simulation, are shown.
Date: May 1, 1995
Creator: Canosa, J.D.; Fiebig, H.R. & Markum, H.
Partner: UNT Libraries Government Documents Department

Strange particle production in hadronic Z{sup 0} decays

Description: A study has been made of neutral strange baryons and pseudoscalar mesons produced in hadronic decays of the weak gauge boson V. The experiment was performed at the Stanford Linear Accelerator Center, which has the unique capability of colliding highly polarized electrons with unpolarized positrons. Overall production rates and spectra of the K{sup 0} and the {Lambda}{sup 0} (+{Lambda}{sup 0}) were measured and compared with other experiments as well as with Quantum Chromodynamics calculations. The combination of the small, stable beam spots produced by the SLAC Linear Collider (SLC) and the precision vertexing capabilities of the SLC Large Detector (SLD) permitted the separation of the hadronic events into three quark flavor-enriched samples. An unfolding was performed to obtain flavor-pure samples, and for the first time measurements were made of K{sup 0} and {Lambda}{sup 0} (+{Lambda}{sup 0}) production rates and spectra in uds, c, and b quark events at the Z{sup 0} pole. This measurement revealed significant production differences. Utilizing the large quark production asymmetry due to the polarized electron beam, high-purity quark and antiquark jet samples were obtained. The first measurement of production differences of the {Lambda}{sup 0} baryon in quark and antiquark jets was performed, which provided clear evidence for a leading particle effect at high momenta.
Date: April 1, 1996
Creator: Baird, K.G. III
Partner: UNT Libraries Government Documents Department

TORO II: A finite element computer program for nonlinear quasi-static problems in electromagnetics: Part 1, Theoretical background

Description: The theoretical and numerical background for the finite element computer program, TORO II, is presented in detail. TORO II is designed for the multi-dimensional analysis of nonlinear, electromagnetic field problems described by the quasi-static form of Maxwell`s equations. A general description of the boundary value problems treated by the program is presented. The finite element formulation and the associated numerical methods used in TORO II are also outlined. Instructions for the use of the code are documented in SAND96-0903; examples of problems analyzed with the code are also provided in the user`s manual. 24 refs., 8 figs.
Date: May 1, 1996
Creator: Gartling, D.K.
Partner: UNT Libraries Government Documents Department

TORO II: A finite element computer program for nonlinear quasi-static problems in electromagnetics: Part 2, User`s manual

Description: User instructions are given for the finite element, electromagnetics program, TORO II. The theoretical background and numerical methods used in the program are documented in SAND95-2472. The present document also describes a number of example problems that have been analyzed with the code and provides sample input files for typical simulations. 20 refs., 34 figs., 3 tabs.
Date: May 1, 1996
Creator: Gartling, D.K.
Partner: UNT Libraries Government Documents Department

Proceedings of the Workshop on Foundations of the Relativistic Theory of Atomic Structure : Held at Argonne National Laboratory, December 4-5, 1980

Description: Although the Dirac theory of the hydrogen atom was proposed more than half a century ago, extension of the theory and its practical applications to complex atomic spectra took decades to mature. Development of quantum electrodynamics (QED) in its modern form, advances in high precision experimental techniques, and invention of high-speed computers have made atomic spectroscopy one of the most accurate branches of physics today, both in theory and experiment. In addition to a long-standing need to identify line-spectra coming from far and near parts of the universe, necessities such as to test QED further and to provide reliable data for ions in tokamak plasmas require an understanding of the theory of relativistic atomic structure beyond the framework of the original Dirac theory. Twenty articles from the proceedings of the workshop are presented. Contributed papers are grouped into theoretical and experimental subjects and presented after the papers for the second (atomic structure calculations) and third (experiment) sessions of the Workshop. Alphabetical listing of the authors is presented in Appendix 1, program of the Workshop in Appendix 2, and the list of the participants in Appendix 3.
Date: March 1981
Creator: Berry, H. G.; Cheng, K. T.; Johnson, W. R. & Kim, Yong-Ki
Partner: UNT Libraries Government Documents Department

Nonlinear electrodynamics in cytoskeletal protein lattices

Description: Cytoskeletal lattice proteins including microtubules are particularly involved in dynamic regulation of intracellular movements and activities. This paper considers possibilities and implications of biological information processing due to coupling of Davydov solitons, Frohlich coherent oscillations and other nonlinear electrodynamic phenomena to conformational states of the grid-like polymer subunits of cytoskeletal microtubules. 39 references.
Date: January 1, 1983
Creator: Hameroff, S.R.; Smith, S.A. & Watt, R.C.
Partner: UNT Libraries Government Documents Department

Summary of the Physics Opportunities Working Group

Description: The Physics Opportunities Working Group was convened with the rather general mandate to explore physic opportunities that may arise as new accelerator technologies and facilities come into play. Five topics were considered during the workshop: QED at critical field strength, novel positron sources, crystal accelerators, suppression of beamstrahlung, and muon colliders. Of particular interest was the sense that a high energy muon collider might be technically feasible and certainly deserves serious study.
Date: December 1, 1992
Creator: Chen, Pisin (Stanford Linear Accelerator Center, Menlo Park, CA (United States)) & McDonald, K.T. (Princeton Univ., NJ (United States). Joseph Henry Labs.)
Partner: UNT Libraries Government Documents Department

Fundamental theory of light for applications: Notes for five informal lectures

Description: These notes give an overview of some aspects of the quantum theory of light and its interaction with matter. A description is given of basic emission and absorption processes, as well as the theory of photodetection and optical coherence. Basic research in this area is increasingly relevant to areas of technological importance, including microlaser devices and the noise characteristics of semiconductor lasers.
Date: June 18, 1993
Creator: Milonni, P.W.
Partner: UNT Libraries Government Documents Department

Test of QED using a laser at the SLAC final focus test beam

Description: Experiment {number sign}144 at SLAC has three parts: the search for low-mass states excited in {gamma}{gamma} collisions and observed in pair decay, the study of nonlinear, nonperturbative QED in {gamma}e and {gamma}{gamma} collisions, and its possible applications to general purpose linear colliders. Such colliders could produce the full range of J{sub q{center dot}{center dot}{bar q}}/{sup PC} states, leptoquarks J{sub l{center dot}{center dot}{bar q}}/{sup PC}, the particles of supersymmetry, the top quark or Higgs. However, to realize them a number of technical problems need resolution that are addressed in E144 together with interesting possibilities for highly polarized, high brightness {gamma}/{sup {yields}} e{sup {yields}{plus minus}} beams that are needed for electroweak studies.
Date: April 1, 1992
Creator: Spencer, J.E.
Partner: UNT Libraries Government Documents Department

Electrokinetic Hydrogen Generation from Liquid WaterMicrojets

Description: We describe a method for generating molecular hydrogen directly from the charge separation effected via rapid flow of liquid water through a metal orifice, wherein the input energy is the hydrostatic pressure times the volume flow rate. Both electrokinetic currents and hydrogen production rates are shown to follow simple equations derived from the overlap of the fluid velocity gradient and the anisotropic charge distribution resulting from selective adsorption of hydroxide ions to the nozzle surface. Pressure-driven fluid flow shears away the charge balancing hydronium ions from the diffuse double layer and carries them out of the aperture. Downstream neutralization of the excess protons at a grounded target electrode produces gaseous hydrogen molecules. The hydrogen production efficiency is currently very low (ca. 10-6) for a single cylindrical jet, but can be improved with design changes.
Date: May 31, 2007
Creator: Duffin, Andrew M. & Saykally, Richard J.
Partner: UNT Libraries Government Documents Department

A capillary valve for microfluidic systems.

Description: Microfluidic systems are becoming increasingly complicated as the number of applications grows. The use of microfluidic systems for chemical and biological agent detection, for example, requires that a given sample be subjected to many process steps, which requires microvalves to control the position and transport of the sample. Each microfluidic application has its own specific valve requirements and this has precipitated the wide variety of valve designs reported in the literature. Each of these valve designs has its strengths and weaknesses. The strength of the valve design proposed here is its simplicity, which makes it easy to fabricate, easy to actuate, and easy to integrate with a microfluidic system. It can be applied to either gas phase or liquid phase systems. This novel design uses a secondary fluid to stop the flow of the primary fluid in the system. The secondary fluid must be chosen based on the type of flow that it must stop. A dielectric fluid must be used for a liquid phase flow driven by electroosmosis, and a liquid with a large surface tension should be used to stop a gas phase flow driven by a weak pressure differential. Experiments were carried out investigating certain critical functions of the design. These experiments verified that the secondary fluid can be reversibly moved between its 'valve opened' and 'valve closed' positions, where the secondary fluid remained as one contiguous piece during this transport process. The experiments also verified that when Fluorinert is used as the secondary fluid, the valve can break an electric circuit. It was found necessary to apply a hydrophobic coating to the microchannels to stop the primary fluid, an aqueous electrolyte, from wicking past the Fluorinert and short-circuiting the valve. A simple model was used to develop valve designs that could be closed using an electrokinetic ...
Date: October 1, 2004
Creator: Cummings, Eric B.; Kanouff, Michael P. & Rush, Brian M.
Partner: UNT Libraries Government Documents Department

Surface Area, Volume, Mass, and Density Distributions for Sized Biomass Particles

Description: This final technical report describes work performed at Morehouse College under DOE Grant No. DE-FC26-04NT42130 during the period July 01, 2004 to June 30, 2007 which covers the entire performance period of the project. 25 individual biomass particles (hardwood sawdust AI14546 in the size range of 100-200 microns) were levitated in an electrodynamic balance (EDB) and their external surface area, volume, and drag coefficient/mass (C{sub d}/m) ratios were characterized applying highly specialized video based and high-speed diode array imaging systems. Analysis methods were employed using shape and drag information to calculate mass and density distributions for these particles. Results of these measurements and analyses were validated by independent mass measurements using a particle weighing and counting technique. Similar information for 28 PSOC 1451D bituminous coal particles was retrieved from a previously published work. Using these two information, density correlations for coal/biomass blends were developed. These correlations can be used to estimate the density of the blend knowing either the volume fraction or the mass fraction of coal in the blend. The density correlations presented here will be useful in predicting the burning rate of coal/biomass blends in cofiring combustors. Finally, a discussion on technological impacts and economic projections of burning biomass with coal in US power plants is presented.
Date: June 30, 2007
Creator: Sampath, Ramanathan
Partner: UNT Libraries Government Documents Department

QED Corrections to the 4p - 4d Transition Energies of Copperlike Heavy Ions

Description: Quantum electrodynamic (QED) corrections to 4p-4d transition energies of several copper-like ions with Z = 70-92 are calculated non-perturbatively in strong external fields to all orders in binding corrections. Dirac-Kohn-Sham potentials are used to account for screening and core-relaxation effects. For the 4p{sub 1/2}-4d{sub 3/2} transition in copperlike bismuth, thorium and uranium, results are in good agreement with empirical QED corrections deduced from differences between transition energies obtained from recent high-precision electron-beam ion-trap (EBIT) measurements and those calculated with the relativistic many-body perturbation theory (RMBPT). These comparisons provide sensitive tests of QED corrections for high angular momentum states in many-electron heavy ions and illustrate the importance of core-relaxation corrections. Comparisons are also made with other theories and with experiment on the 4s-4p transition energies of high-Z Cu-like ions as accuracy checks of the present RMBPT and QED calculations.
Date: August 21, 2006
Creator: Chen, M H; Cheng, K T; Johnson, W R & Sapirstein, J
Partner: UNT Libraries Government Documents Department

Incorporating Electrokinetic Phenomena into EBNavierStokes

Description: Motivated by the recent interest in using electrokinetic effects within microfluidic devices, they have extended the EBNavierStokes code to be able to handle electrokinetic effects. With this added functionality, the code becomes more useful for understanding and designing microfluidic devices that take advantage of electrokinetic effects (e.g. pumping and mixing). Supporting the simulation of electrokinetic effects required three main extensions to the existing code: (1) addition of an electric field solver, (2) development of a module for accurately computing the Smulochowski slip-velocity at fluid-solid boundaries, and (3) extension of the fluid solver to handle nonuniform inhomogeneous Dirichlet boundary conditions. The first and second extensions were needed to compute the electrokinetically generated slip-velocity at fluid-solid boundaries. The third extension made it possible for the fluid flow to be driven by a slip-velocity boundary condition (rather than by a pressure difference between inflow and outflow). In addition, several small changes were made throughout the code to make it compatible with these extensions. This report documents the changes to the EBNavierStokes code required to support the simulation of electrokinetic effects. They begin with a brief overview of the problem of electrokinetically driven flow. Next, they present a detailed description of the changes to the EBNavierStokes code. Finally, they present some preliminary results and discuss future directions and improvements to the code.
Date: January 10, 2006
Creator: Chu, K & Trebotich, D
Partner: UNT Libraries Government Documents Department