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Realizing the potential of quarkonium

Description: I recall the development of quarkonium quantum mechanics after the discovery of {Upsilon}. I emphasize the empirical approach to determining the force between quarks from the properties of c{anti c} and b{anti b} bound states. I review the application of scaling laws, semiclassical methods, theorems and near-theorems, and inverse- scattering techniques. I look forward to the next quarkonium spectroscopy in the B{sub c} system.
Date: July 1, 1997
Creator: Quigg, C.
Partner: UNT Libraries Government Documents Department


Description: It is the purpose of this research to study electrostatic charging mechanisms related to electrostatic beneficiation of coal with the goal of improving models of separation and the design of electrostatic separators. Areas addressed in this technical progress report are (a) electrostatic beneficiation of Pittsburgh #8 coal powders as a function of grind size and processing atmosphere; (b) the use of fluorescent micro-spheres to probe the charge distribution on the surfaces of coal particles; (c) the use of electrostatic beneficiation to recover unburned carbon from flyash; (d) the development of research instruments for investigation of charging properties of coal. Pittsburgh #8 powders were beneficiated as a function of grind size and under three atmosphere conditions: fresh ground in air , after 24 hours of air exposure, or under N2 atmosphere. The feed and processed powders were analyzed by a variety of methods including moisture, ash, total sulfur, and pyritic sulfur content. Mass distribution and cumulative charge of the processed powders were also measured. Fresh ground coal performed the best in electrostatic beneficiation. Results are compared with those of similar studies conducted on Pittsburgh #8 powders last year (April 1, 1997 to September 30, 1997). Polystyrene latex spheres were charged and deposited onto coal particles that had been passed through the electrostatic separator and collected onto insulating filters. The observations suggest bipolar charging of individual particles and patches of charge on the particles which may be associated with particular maceral types or with mineral inclusions. A preliminary investigation was performed on eletrostatic separation of unburned carbon particles from flyash. Approximately 25% of the flyash acquired positive charge in the copper tribocharger. This compares with 75% of fresh ground coal. The negatively charged material had a slightly reduced ash content suggesting some enrichment of carbonaceous material. There was also evidence that the ...
Date: December 1, 1998
Partner: UNT Libraries Government Documents Department

Charged Local Defects in Extended Systems

Description: The conventional approach to treating charged defects in extended systems in first principles calculations is via the supercell approximation using a neutralizing jellium background charge. I explicitly demonstrate shortcomings of this standard approach and discuss the consequences. Errors in the electrostatic potential surface over the volume of a supercell are shown to be comparable to a band gap energy in semiconductor materials, for cell sizes typically used in first principles simulations. I present an alternate method for eliminating the divergence of the Coulomb potential in supercell calculations of charged defects in extended systems that embodies a correct treatment of the electrostatic potential in the local viciniq of the a charged defect, via a mixed boundary condition approach. I present results of first principles calculations of charged vacancies in NaCl that illustrate the importance of polarization effects once an accurate representation of the local potential is obtained. These polarization effects, poorly captured in small supercells, also impact the energetic on the scale of typical band gap energies.
Date: May 25, 1999
Creator: Schultz, Peter A.
Partner: UNT Libraries Government Documents Department

Mechanisms for charge-transfer processes at electrode/solid-electrolyte interfaces.

Description: This report summarizes the accomplishments of a Laboratory-Directed Research and Development (LDRD) project focused on developing and applying new x-ray spectroscopies to understand and improve electric charge transfer in electrochemical devices. Our approach studies the device materials as they function at elevated temperature and in the presence of sufficient gas to generate meaningful currents through the device. We developed hardware and methods to allow x-ray photoelectron spectroscopy to be applied under these conditions. We then showed that the approach can measure the local electric potentials of the materials, identify the chemical nature of the electrochemical intermediate reaction species and determine the chemical state of the active materials. When performed simultaneous to traditional impedance-based analysis, the approach provides an unprecedented characterization of an operating electrochemical system.
Date: November 1, 2011
Creator: Chueh, William; El Gabaly Marquez, Farid; Whaley, Josh A.; McCarty, Kevin F.; McDaniel, Anthony H. & Farrow, Roger L.
Partner: UNT Libraries Government Documents Department


Description: Phase acceptance of the Alternating-Gradient Synchrotron Linear Accelerator is theoretically examined and found to agree well with an experimental determination of phase acceptance. Bunching in the AGS linac is also analyzed, the results indicating a satisfactory understanding of this process also. A double buncher that should be more efficient than the present single buncher is discussed, and space charge effects (as yet unobserved in bunching) are analyzed. (D.C.W.)
Date: March 27, 1963
Creator: Blewett, J.P.
Partner: UNT Libraries Government Documents Department

Search for fractionally charged quarks at ISABELLE

Description: A relatively simple experiment is proposed which is sensitive to conventional quarks of charge 1/3 or 2/3e and mass less than 200 GeV. The experiment uses a modest amount of conventional equipment, no magnetic momentum analysis, and in a period of one week will achieve a sensitivity of 10$sup - 36$cm$sup 2$ to isotropic quark production. Despite the experimental simplicity, the signature provided by a fractionally charged quark should be unambiguous. The method and apparatus are described, background and counting rates are discussed, and finally a cost estimate is given for this experiment. (JFP)
Date: January 1, 1975
Creator: Foley, K.J. & Meadows, B.T.
Partner: UNT Libraries Government Documents Department


Description: Almost from the moment in June 1977 when the discovery of the Upsilon resonance revealed the existence of what we now call the bottom quark, physicists began searching for its partner. Through the years, as we established the electric charge and weak isospin of the b-quark, and detected the virtual influence of its mate, it became clear that the top quark must exist. Exactly at what mass, we couldn't say, but we knew just how top events would look. We also knew that top events would be rare--if the Tevatron could make them at all--and that picking out the events would pose a real challenge for the experimenters and their detectors.
Date: January 1, 2008
Creator: Quigg, Chris
Partner: UNT Libraries Government Documents Department

Continuing scearch for a new type charging belt

Description: The EN Tandem accelerator at Oak Ridge National Laboratory (ORNL) operates to support a varied program of atomic physics research. As such, the demands on the accelerator often require a range of operation from {approximately}0.38 to 7.0 MV on the terminal, with low ripple and long term steady state operation. The standard charging belts obtained from the manufacture have generally given acceptable performance, but it is reasonable that modem manufacturing techniques and materials could increase belt lifetimes and improve accelerator performance, particularly voltage ripple. A new belt of significantly different construction from that of the conventional belts was specified, purchased, and installed in 1993. After 2800 hours of use at voltages from 0.38 to 5.8 MV, it was removed from the accelerator in early August 1995.
Date: December 31, 1995
Creator: Jones, N.L.
Partner: UNT Libraries Government Documents Department

3-D Finite Element Analysis of Induction Logging in a Dipping Formation

Description: Electromagnetic induction by a magnetic dipole located above a dipping interface is of relevance to the petroleum well-logging industry. The problem is fully three-dimensional (3-D) when formulated as above, but reduces to an analytically tractable one-dimensional (1-D) problem when cast as a small tilted coil above a horizontal interface. The two problems are related by a simple coordinate rotation. An examination of the induced eddy currents and the electric charge accumulation at the interface help to explain the inductive and polarization effects commonly observed in induction logs from dipping geological formations. The equivalence between the 1-D and 3-D formulations of the problem enables the validation of a previously published finite element solver for 3-D controlled-source electromagnetic induction.
Date: July 20, 2000
Creator: Everett, Mark E.; Badea, Eugene A,; Shen, Liang, C.; Merchant, Gulamabbas A. & Weiss, Chester J.
Partner: UNT Libraries Government Documents Department

Measured environments within 20 meters of the strike points of triggered lightning

Description: Vertical electric fields, azimuthal magnetic fields, and earth voltages developed over 0.5-m radial step distances have been measured at 10 and 20 m from the ground attachment point of triggered lightning. The magnetic fields are found to follow Ampere`s law closely. The relationship between maximum vertical electric field change due to a descending dart leader and the peak of its associated return-stroke current is linear. Recorded earth step voltages have the same waveforms as the incident return-stroke currents, and, for distances between 10 and 20 m from the strike point, their amplitudes exhibit a 1/r dependence. Statistics are given for observed radial filamentary arcing from the ground attachment point.
Date: August 1, 1995
Creator: Fisher, R.J.; Schnetzer, G.H. & Morris, M.E.
Partner: UNT Libraries Government Documents Department

A Search for Neutrinoless Tau Decays to Three Leptons

Description: Using approximately 350 million {tau}{sup +}{tau}{sup -} pair events recorded with the BaBar detector at the Stanford Linear Accelerator Center between 1999 and 2006, a search has been made for neutrinoless, lepton-flavor violating tau decays to three lighter leptons. All six decay modes consistent with conservation of electric charge and energy have been considered. With signal selection efficiencies of 5-12%, we obtain 90% confidence level upper limits on the branching fraction {Beta}({tau} {yields} {ell}{ell}{ell}) in the range (4-8) x 10{sup -8}.
Date: September 24, 2008
Creator: Kolb, Jeffrey A. & /SLAC, /Oregon U.
Partner: UNT Libraries Government Documents Department


Description: A basic study of the mechanism of deposition of small particles on cylindrical collectors in the presence of electrostatic forces has been made. Theoretical equations predicting the efficiency of collection have been derived and solved with a digital computer. The solution of these equations is shown. The deposition of liquid aerosol particles on cylindrical collectors was measured experimentally for a range of electrostatic conditions. The experimental results agree with the theory. An experimental study was made of the effect of electrical charges on aerosol particles on the filtration efficiency of glass fiber mats. Experiments were also made on the effect of placing a potential on a mat of fine wire and on filtration by a mat of a tangled wire dipole. (auth)
Date: March 15, 1958
Creator: Dawkins, G.S.
Partner: UNT Libraries Government Documents Department

X-ray resonant magnetic scattering investigations of hexagonal multiferroics RMnO3 (R = Dy, Ho, Er)

Description: Electricity and magnetism were unified into a common subject by James Clerk Maxwell in the nineteenth century yielding the electromagnetic theory. Four equations govern the dynamics of electric charges and magnetic fields, commonly known as Maxwell's equations. Maxwell's equations demonstrate that an accelerated charged particle can produce magnetic fields and a time varying magnetic field can induce a voltage - thereby linking the two phenomena. However, in solids, electric and magnetic ordering are most often considered separately and usually with good reason: the electric charges of electrons and ions are responsible for the charge effects, whereas the electron spin governs magnetic properties.
Date: December 19, 2009
Creator: Nandi, Shibabrata
Partner: UNT Libraries Government Documents Department