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The streaming potential of liquid carbon dioxide in BreaSandstone

Description: We report here, for the first time, evolution of the streaming potential coupling coefficient as liquid carbon dioxide infiltrates Berea sandstone. Using 125 Omega-m tap water, the coupling coefficient determined before and after each CO2 flood of five samples averaged approximately -30 mV/0.1 MPa. After liquid CO2 passed through the specimens displacing all mobile pore water, trapped water remained and the coupling coefficient was approximately -3 mV/0.1 MPa. A bound water limit of the coupling coefficient for liquid CO2 flow was found using an air-dried sample to be -0.02 mV/0.1 MPa. For initially water-saturated samples, bulk resistivity varied during CO2 invasion from 330 Ohm-m, to 150 Ohm-m during CO2/water mixing, to a final value of 380 Ohm-m. Results suggest that trapped and bound water control electrical conduction and the electrokinetic response. Applications include monitoring CO2 injectate in subsurface reservoirs using the self potential method.
Date: October 1, 2004
Creator: Moore, J.; Glaser, S.; Morrison, F. & Hoversten, G.M.
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

Binary electrokinetic separation of target DNA from background DNA primers.

Description: This report contains the summary of LDRD project 91312, titled ''Binary Electrokinetic Separation of Target DNA from Background DNA Primers''. This work is the first product of a collaboration with Columbia University and the Northeast BioDefense Center of Excellence. In conjunction with Ian Lipkin's lab, we are developing a technique to reduce false positive events, due to the detection of unhybridized reporter molecules, in a sensitive and multiplexed detection scheme for nucleic acids developed by the Lipkin lab. This is the most significant problem in the operation of their capability. As they are developing the tools for rapidly detecting the entire panel of hemorrhagic fevers this technology will immediately serve an important national need. The goal of this work was to attempt to separate nucleic acid from a preprocessed sample. We demonstrated the preconcentration of kilobase-pair length double-stranded DNA targets, and observed little preconcentration of 60 base-pair length single-stranded DNA probes. These objectives were accomplished in microdevice formats that are compatible with larger detection systems for sample pre-processing. Combined with Columbia's expertise, this technology would enable a unique, fast, and potentially compact method for detecting/identifying genetically-modified organisms and multiplexed rapid nucleic acid identification. Another competing approach is the DARPA funded IRIS Pharmaceutical TIGER platform which requires many hours for operation, and an 800k$ piece of equipment that fills a room. The Columbia/SNL system could provide a result in 30 minutes, at the cost of a few thousand dollars for the platform, and would be the size of a shoebox or smaller.
Date: October 1, 2005
Creator: James, Conrad D. & Derzon, Mark Steven
Partner: UNT Libraries Government Documents Department

The $\hbar$ Expansion in Quantum Field Theory

Description: We show how expansions in powers of Planck's constant {h_bar} = h = 2{pi} can give new insights into perturbative and nonperturbative properties of quantum field theories. Since {h_bar} is a fundamental parameter, exact Lorentz invariance and gauge invariance are maintained at each order of the expansion. The physics of the {h_bar} expansion depends on the scheme; i.e., different expansions are obtained depending on which quantities (momenta, couplings and masses) are assumed to be independent of {h_bar}. We show that if the coupling and mass parameters appearing in the Lagrangian density are taken to be independent of {h_bar}, then each loop in perturbation theory brings a factor of {h_bar}. In the case of quantum electrodynamics, this scheme implies that the classical charge e, as well as the fine structure constant are linear in {h_bar}. The connection between the number of loops and factors of {h_bar} is more subtle for bound states since the binding energies and bound-state momenta themselves scale with {h_bar}. The {h_bar} expansion allows one to identify equal-time relativistic bound states in QED and QCD which are of lowest order in {h_bar} and transform dynamically under Lorentz boosts. The possibility to use retarded propagators at the Born level gives valence-like wave-functions which implicitly describe the sea constituents of the bound states normally present in its Fock state representation.
Date: October 27, 2010
Creator: Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; Hoyer, Paul & /Southern Denmark U., CP3-Origins /Helsinki U. /Helsinki Inst. of Phys.
Partner: UNT Libraries Government Documents Department

Atomic collisions with 33-TeV lead ions

Description: Recent availability of relativistic and ultrarelativistic beams of heavy ions has permitted the first controlled studies of atomic collisions at energies sufficient to measure effects of several new basic phenomena. These include measurements substantiating recently predicted finite nuclear size effects resulting in a reduction in the total electronic energy loss of heavy ions in matter, and measurements of Coulomb collisions in which electrons are excited from the Dirac negative energy continuum. Measurements of total energy loss, free electron-positron pair production, and electron capture from pair production have been recently performed using 33-TeV Pb{sup 82+} ions from the CERN SPS accelerator in Geneva. Results of these studies are presented, along with comparisons with relevant theory.
Date: October 1, 1996
Creator: Vane, C.R.; Datz, S. & Krause, H.F.
Partner: UNT Libraries Government Documents Department

Testing and evaluation of electrokinetic decontamination of concrete

Description: The goals and objectives of the technical task plan (TTP) are to (1) describe the nature and extent of concrete contamination within the Department of Energy (DOE) complex and emerging and commercial technologies applicable to these problems; (2) to match technologies to the concrete problems and recommend up to four demonstrations; (3) to initiate recommended demonstrations; and (4) to continue investigation and evaluation of the application of electrokinetic decontamination processes to concrete. This document presents findings of experimental and theoretical studies of the electrokinetic decontamination (EK) process and their implications for field demonstrations. This effort is an extension of the work performed under TTP 142005, ``Electroosmotic Concrete Decontamination. The goals of this task were to determine the applicability of EK for treating contaminated concrete and, if warranted, to evaluate EK as a potential technology for demonstration. 62 refs.
Date: October 1, 1996
Creator: DePaoli, D.W.; Harris, M.T. & Ally, M.R.
Partner: UNT Libraries Government Documents Department

Test of QED at critical field strength

Description: In a new experiment at the Final Focus Test Beam at SLAC, a low-emittance 46.6 GeV electron beam is brought into collision with terawatt pulses of 1,054 nm or 527 nm wavelength from a Nd:glass laser. Peak laser intensities of 10{sup 18} W/cm{sup 2} have been achieved corresponding to a value of 0.6 for the parameter {eta} = e{var_epsilon}m{omega}{sub 0}c. In this case, an electron that crosses the center of the laser pulse has near-unit interaction probability. Results are presented for multiphoton Compton scattering in which an electron interacts with up to four laser photons, in agreement with theoretical calculations.
Date: October 1, 1996
Creator: Bula, C. & Collaboration, E-144
Partner: UNT Libraries Government Documents Department

Quantum-Classical Correspondence in Nonrelativistic Electrodynamics

Description: A form of classical electrodynamic field exists which gives exact agreement with the operator field of quantum electrodynamics (QED) for the Lamb shift of a harmonically bound point electron. Here it is pointed out that this form of classical theory with its physically acceptable interpretation is the result of an unconventional resolution of a mathematically ambiguous term in classical field theory. Finally a quantum-classical correspondence principle is shown to exist in the sense that the classical field and expectation value of the QED operator field are identical if retardation is neglected in the latter.
Date: October 14, 1999
Creator: Ritchie, A.B. & Weatherford, C.A.
Partner: UNT Libraries Government Documents Department

Progress report for a research program in theoretical high-energy physics. [Summaries of research activities at Brown University]

Description: Last year's research program dealt with a variety of topics including small-p/sub perpendicular/ hadronic phenomenology (dual topological unitarization, Pomeron-f identity hypothesis, t-channel approach to diffraction peak and hadron size, tunneling in Reggeon field theory); bound-state problems in quantum electrodynamics (positronium decay, hyperfine splitting of positronium and muonium); quantum field theory (graph counting, strong-coupling solutions for eikonal problems with SU(2) constraints, unitarity restriction and semi-classical solutions, quark confinement); unified gauge models of weak and electromagnetic interactions (Weinberg-Salam model, exclusion of effective V/sub e/V/sub N/ + A/sub e/A/sub N/ neutral-current interaction, Cabibbo angle and quark mass ratios); bound-state mean field theory (structural equivalence of two-dimensional four-fermion and Yukawa-like models, renormalization of four-dimensional four-fermion models, Fermi theory of weak interactions as a Yang-Mills theory); acoustic detection of cosmic neutrinos; topics in gravitation and cosmology; as well as other studies involving the interactions of elementary particles. A list of publications is included.
Date: October 1, 1978
Creator: Feldman, D.
Partner: UNT Libraries Government Documents Department

Recent results from PEP

Description: Preliminary results are presented for the data taken by the MARK II and MAC collaborations at the PEP storage ring. Results include measurements of QED processes, limits on the weak couplings g/sub V/ and g/sub A/, limits on anomalous lepton production, the measurement of the tau lifetime, scale violation in inclusive hadron production, Monte Carlo independent tests of QCD using energy-energy correlations and single jet energy moments, measurements of the properties of three jet events, and measurements of proton, neutral kaon, lambda and proton pair yields.
Date: October 1, 1981
Creator: Hollebeek, R.
Partner: UNT Libraries Government Documents Department

Research program in theoretical high-energy physics. Progress report. [Summaries of research activities at Brown Univ]

Description: Last year's research program dealt with a large range of topics in high energy theoretical physics. Included in the problems studied were: flavor mixing angles in flavor gauge theory; grand unification schemes; neutral current phenomenology; charmonium decays; perturbative aspects of soft hadronic phenomena within the framework of the dual topological expansion; Regge trajectory slopes and the shape of the inclusive spectra; bound states in quantum electrodynamics; calculations of the Lamb Shift and hyperfine splitting in hydrogen (and muonium) through order ..cap alpha..(Z..cap alpha..)/sup 6/; perturbation theory resummation techniques; collective behavior of instantons in quantum chromodynamics; 1/N expansion and mean field expansion techniques (applied to the nonlinear sigma model, classical solutions to Yang-Mills theories, and renormalized four-Fermi models of weak interactions); semiclassical calculation of Z/sub 1/(..cap alpha..) in scalar QED; group theoretic studies of spontaneous symmetry breaking; fibre bundles applied to the topological aspects of gauge theories; strong-coupling expansions (as an aspect of infrared behavior, as a systematic perturbation expansion with reference to lattice extrapolation, applied to classical statistical mechanics, applied to problems with nonquadratic kinetic energy terms, and in transfer matrix formulations); eikonal methods (three-body Coulomb scattering, quark-antiquark potentials); computer augmented solutions to quantum field theory; topological excitations in two-dimensional models and WKB approximation on a lattice. A list of publications is included.
Date: October 1, 1979
Creator: Feldman, D.; Fried, H.M. & Guralnik, G.S.
Partner: UNT Libraries Government Documents Department

Beamstrahlung and QED backgrounds at future linear colliders

Description: This dissertation is a detailed study of several aspects of beamstrahlung and related phenomena. The problem is formulated as the relativistic scattering of an electron from a strong but slowly varying potential. The solution is readily interpreted in terms of a classical electron trajectory, and differs from the solution of the corresponding classical problem mainly in the effect of quantum recoil due to the emission of hard photons. When the general solution is expanded for the case of an almost-uniform field, the leading term is identical to the well-known formula for quantum synchrotron radiation. The first non-leading term is negligible in all cases of interest where the expansion is valid. In applying the standard synchrotron radiation formula to the beamstrahlung problem, the effects of radiation reaction on the emission of multiple photons can be significant for some machine designs. Another interesting feature is the helicity dependence of the radiation process, which is relevant to the case where the electron beam is polarized. The inverse process of coherent electron-positron pair production by a beamstrahlung photon is a potentially serious background source at future colliders, since low-energy pairs can exit the bunch at a large angle. Pairs can also be produced incoherently by the collision of the two photons, either real or virtual. The rates, spectra, and angular distributions for both the coherent and incoherent processes are estimated here. At a 1/2 TeV machine the incoherent process will be more common, resulting in roughly 10{sup 6} pairs per bunch crossing. One member of each pair is always pushed outward, at an angle determined by its energy, by the field of the oncoming bunch. In addition, a small number of pairs are initially produced with a comparable or larger angle.
Date: October 1, 1990
Creator: Schroeder, D.V.
Partner: UNT Libraries Government Documents Department

Research in particle theory

Description: Dynamics of 2+1 dimensional gravity is analyzed by coupling matter to Chern Simons Witten action in two ways and obtaining the exact gravity Hamiltonian for each case. 't Hoot's Hamiltonian is obtained as an approximation. The notion of space-time emerges in the very end as a broken phase of the gauge theory. We have studied the patterns of discrete and continuous symmetry breaking in 2+1 dimensional field theories. We formulate our analysis in terms of effective composite scalar field theories. Point-like sources in the Chern-Simons theory of gravity in 2+1 dimensions are described by their Poincare' charges. We have obtained exact solutions of the constraints of Chern-Simons theory with an arbitrary number of isolated point sources in relative motion. We then showed how the space-time metric is constructed. A reorganized perturbation expansion with a propagator of soft infrared behavior has been used to study the critical behavior of the mass gap. The condition of relativistic covariance fixes the form of the soft propagator. Approximants to the correlation critical exponent were obtained in two loop order for the two and three dimensional theories. We proposed a new model of QED exhibiting two phases and a Majorana mass spectrum of single particle states. The model has a new source of coupling constant renormalization which opposes screening and suggests the model may confine. Assuming that the bound states of e{sup +}e{sup {minus}} essentially obey a Majorana spectrum, we obtained a consistent fit of the GSI peaks as well as predicting new peaks and their spin assignments.
Date: October 1, 1992
Creator: Mansouri, F.; Suranyi, P. & Wijewardhana, L.C.R.
Partner: UNT Libraries Government Documents Department

Dynamics of symmetry breaking in strongly coupled QED

Description: I review the dynamical structure of strong coupled QED in the quenched planar limit. The symmetry structure of this theory is examined with reference to the nature of both chiral and scale symmetry breaking. The renormalization structure of the strong coupled phase is analysed. The compatibility of spontaneous scale and chiral symmetry breaking is studied using effective lagrangian methods. 14 refs., 3 figs.
Date: October 1, 1988
Creator: Bardeen, W.A.
Partner: UNT Libraries Government Documents Department

Review of e/sup +/e/sup -/ physics at PEP - 1982

Description: Results obtained at PEP by the MARK II, MAC and DELCO collaborations in the past year are reviewed. They include QED tests, measurements of tau lepton properties, charm and bottom fragmentation functions, scaling violations, energy correlations and the total hadronic cross section.
Date: October 1, 1982
Creator: Hollebeek, R.
Partner: UNT Libraries Government Documents Department

Measurement of the magnetically-induced QED birefringence of the vacuum and an improved search for laboratory axions: Technical report. Project definition study of the use of assets and facilities of the Superconducting Super Collider Laboratory

Description: The Colorado State Collaboration has studied the feasibility of a high sensitivity QED birefringence/axion search measurement. The objective of this work is to measure, for the first time, the birefringence induced in the vacuum on a light beam travelling in a powerful magnetic field. The same experimental setup also allows a highly sensitive search for axion or axion-like particles. The experiment would combined custom-designed optical heterodyne interferometry with a string of six SSC prototype superconducting dipole magnets at the N-15 site of the SSC Laboratory. With these powerful laser tools, sensitivity advances of 10{sup 7} to 10{sup 9} over previous optical experiments will be possible. The proposed experiment will be able to measure the QED light-by-light scattering effect with a 0.5% accuracy. The increased sensitivity for the axion-two photon interaction will result in a bound on this process rivaling the results based on astrophysical arguments. In the technical report the authors address the scientific significance of these experiments and examine the limiting technical parameters which control their feasibility. The proposed optical/electronic scheme is presented in the context of a background of the known and projected systematic problems which will confront any serious attempt to make such measurements.
Date: October 31, 1994
Creator: Lee, S. A.; Fairbank, W. M. Jr.; Toki, W. H.; Hall, J. L.; Kraushaar, P. F. Jr. & Jaffery, T. S.
Partner: UNT Libraries Government Documents Department

An essay on discrete foundations for physics

Description: We base our theory of physics and cosmology on the five principles of finiteness, discreteness, finite computability, absolute non- uniqueness, and strict construction. Our modeling methodology starts from the current practice of physics, constructs a self-consistent representation based on the ordering operator calculus and provides rules of correspondence that allow us to test the theory by experiment. We use program universe to construct a growing collection of bit strings whose initial portions (labels) provide the quantum numbers that are conserved in the events defined by the construction. The labels are followed by content strings which are used to construct event-based finite and discrete coordinates. On general grounds such a theory has a limiting velocity, and positions and velocities do not commute. We therefore reconcile quantum mechanics with relativity at an appropriately fundamental stage in the construction. We show that events in different coordinate systems are connected by the appropriate finite and discrete version of the Lorentz transformation, that 3-momentum is conserved in events, and that this conservation law is the same as the requirement that different paths can ''interfere'' only when they differ by an integral number of deBroglie wavelengths. 38 refs., 12 figs., 3 tabs.
Date: October 5, 1988
Creator: Noyes, H.P. & McGoveran, D.O.
Partner: UNT Libraries Government Documents Department