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Aerospace, Physics, and Space Science Faculty Publications

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Full-Text Articles in Physical Sciences and Mathematics

The Physical Properties Of Double Degenerate Common Proper Motion Binaries, Edward M. Sion, Terry D. Oswalt, James Liebert, Paul Hintsen Apr 1991

The Physical Properties Of Double Degenerate Common Proper Motion Binaries, Edward M. Sion, Terry D. Oswalt, James Liebert, Paul Hintsen

Aerospace, Physics, and Space Science Faculty Publications

We present spectral types and spectrophotometry for 21 double degenerate (DD) common proper motion binaries and provide estimates of their colors, absolute visual and bolometric magnitudes, and cooling ages. The most typical double degenerate pair contains stars of similar color and spectral type, with an average Mv = 14.20, and average cooling age of ≈3×10⁹ yr, thus typically belonging to the extremely old disk population subcomponent. The oldest pairs in the sample are 9 × 10⁹ yr. The differential cooling ages, Δ log τc, range between 0.01 and 0.84, with the most typical pair having Δ log τc = 0.30, …

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Uv Observations Of The Cool Dbqa5 White Dwarf Lds 678a: Limits On The Atmospheric Composition, Pressure Shift, And Gravitational Redshift Derived From C I 2479, Terry D. Oswalt, Edward M. Sion, Gordon Hammond, James W. Liebert, Gary Wegner, Detlev Koester, Pamela M. Marcum Feb 1991

Uv Observations Of The Cool Dbqa5 White Dwarf Lds 678a: Limits On The Atmospheric Composition, Pressure Shift, And Gravitational Redshift Derived From C I 2479, Terry D. Oswalt, Edward M. Sion, Gordon Hammond, James W. Liebert, Gary Wegner, Detlev Koester, Pamela M. Marcum

Aerospace, Physics, and Space Science Faculty Publications

We present a high-resolution ultraviolet spectrum of the helium-rich degenerate LDS 678A, obtained with the International Ultraviolet Explorer (IUE) satellite. LDS 678A is the coolest metallic line degenerate (DQ or DZ) yet observed with the IUE echelle. These observations provide a detailed line profile of the strong C I 2479 absorption line and equivalent width W₂₄₇₉ = 2.35 ± 0.06 Å from which theoretical profile fits yield a carbon abundance of log C/He = (-6.7 ± 0.2). The presence of carbon in a Herich atmosphere lends credence to the notion that LDS 678A is a transitional case between the DB …

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Gaussian Reference Auid And Interpretation Of Quantum Geometrodynamics, Karel V. Kucha, Charles G. Torre Jan 1991

Gaussian Reference Auid And Interpretation Of Quantum Geometrodynamics, Karel V. Kucha, Charles G. Torre

Aerospace, Physics, and Space Science Faculty Publications

The of vacuum geometrodynamics is turned into a Schrödinger equation by imposing the normal Gaussian coordinate conditions with s and then restoring the coordinate invariance of the action by parametrization. This procedure corresponds to coupling the gravitational field to a reference fluid. The source appearing in the Einstein law of gravitation has the structure of a heat-conducting dust. When one imposes only the Gaussian time condition but not the Gaussian frame conditions, the heat flow vanishes and the dust becomes incoherent. The canonical description of the fluid uses the Gaussian coordinates and their conjugate momenta as the fluid variables. The …

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Four Short-Period Algols, James Bruce Rafert Oct 1990

Four Short-Period Algols, James Bruce Rafert

Aerospace, Physics, and Space Science Faculty Publications

We have analyzed the light curves of four close binary star systems (BV 267, RU UMi, XZ CMi, and VV UMa) using the Wilson-Devinney differential corrections model. The present system geometries of these binaries is that of short-period, semi-detached systems with Roche lobe filling secondaries and main-sequence primaries. Differential coordinates in the mass-luminosity and mass-radius diagrams indicate that the secondary components lie near the main sequence, except in the case of BV 267. It is suggested that these systems are binaries with slightly overluminous and over-sized secondaries which have undergone case A mass transfer. This contention is supported by timing …

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Analytic Variational Method For Hamiltonian Lattice Gauge Theory In 3+ 1 Dimensions, Ming C. Huang, Mohammad W. Katoot Mar 1990

Analytic Variational Method For Hamiltonian Lattice Gauge Theory In 3+ 1 Dimensions, Ming C. Huang, Mohammad W. Katoot

Aerospace, Physics, and Space Science Faculty Publications

We present an analytic d in 3 + 1 dimensions for Hamiltonian lattice gauge theory. This method is based on Batrouni's mean-plaquette method and space integration. The Abelianized Bianchi identities are used and a detailed study of the number of identities that are needed and the validity of this approximation is given. The we use is the product of single-plaquette wave functions. The guage group we consider here is SU(2), but the method is valid for any gauge theory. We apply this method to calculate the 0++ glueball mass, and, in addition, the results of the string tension (scaling is …

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Perturbations Of Gravitational Instantons, Charles G. Torre Jan 1990

Perturbations Of Gravitational Instantons, Charles G. Torre

Aerospace, Physics, and Space Science Faculty Publications

Ashtekar's spinorial formulation of general relativity is used to study perturbations of gravitational instantons corresponding to finite-action solutions of the Euclidean Einstein equations (with a nonzero cosmological constant) possessing an anti-self-dual Weyl curvature tensor. It is shown that, with an appropriate "on-shell" form of infinitesimal gauge transformations, the space of solutions to the can be described in terms of an elliptic complex; the cohomology of the complex defines gauge-inequivalent perturbations. Using this elliptic complex we prove that there are no nontrivial solutions to the linearized instanton equation on conformally anti-self-dual Einstein spaces with a positive cosmological constant. Thus, the space …

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Hamiltonian Formulation Of Induced Gravity In Two Dimensions, Charles G. Torre Oct 1989

Hamiltonian Formulation Of Induced Gravity In Two Dimensions, Charles G. Torre

Aerospace, Physics, and Space Science Faculty Publications

A Hamiltonian formulation of the theory of induced gravity in two dimensions is constructed. This formulation differs from previous efforts in that the formalism is covariant under all relevant transformation groups. In particular, spatial diffeomorphism covariance and/or invariance is manifest throughout; the phase space carries a representation of the Lie algebra of the spacetime diffeomorphism group; the group of conformal isometries is projectively represented on the phase space as a symmetry group. The key ingredient that allows covariance with respect to the above groups is the enlargement of the gravitational phase space by the inclusion of the cotangent bundle over …

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Generation Of Moire Contours With Acousto-Optic Cells, Joel H. Blatt, Huey-Chin Chang Ho, Eddie H. Young Jan 1988

Generation Of Moire Contours With Acousto-Optic Cells, Joel H. Blatt, Huey-Chin Chang Ho, Eddie H. Young

Aerospace, Physics, and Space Science Faculty Publications

Moire contours are seen on a curved surface viewed through a grating when the surface is illuminated with a matched grating. We have been able to replace both the projection and viewing physical gratings with gratings of variable spacing generated in acousto-optic cells, and have been able to observe and record Moire contours. The gratings are generated by amplitude modulating 70 MHz AO cells with a 1 to 10 MHz square wave. The gratings become visible on the curved object by strobing the illuminating laser beam with 50 nsec pulses by means of an AO modulator. Data is given showing …

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Activity Coefficient And The Einstein Relation, Peter T. Landsberg, Albert G. Guy Jul 1983

Activity Coefficient And The Einstein Relation, Peter T. Landsberg, Albert G. Guy

Aerospace, Physics, and Space Science Faculty Publications

A connection between the activity coefficient of current carriers and the Einstein relations is established by two methods, one based on normal semiconductor concepts and one based on irreversible thermodynamics. The connection holds for all densities of states, for Fermi degeneracy, and in the presence of heavy doping.

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Mossbauer Measurements With '"Au In Aua1„Auga„Auin„And Ausb, John O. Thomson, Felix E. Obenshain, Paul G. Huray, John C. Love, John W. Burton Mar 1975

Mossbauer Measurements With '"Au In Aua1„Auga„Auin„And Ausb, John O. Thomson, Felix E. Obenshain, Paul G. Huray, John C. Love, John W. Burton

Aerospace, Physics, and Space Science Faculty Publications

Mossbauer spectra for '"Au in Au metal and the intermetallic compounds AuAl„AuGa„AuIn„and AuSb2 have been obtained for the temperature range 4.2 to 95'K. The isomer shifts for these absorbers with respect to a ' Au in Pt source are —1.223(2) [Au metal], + 2.288(12) [AuSb2], + 3.489(4) [AuIn2], +4.450(11) [AuGa, ], and +.5.967(5) [AuAl, ] in units of mm/sec. The difference in isomer shifts (alloy-Au-metal) may be interpreted in terms of an increasing electron charge density at the Au nucleus in the alloys as compared to that of Au metal. When volume changes for the alloys with respect to the …

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One-Dimensional Three-Body Scattering Problem Used As A Testing Ground For The K-Matrix Method For Scattering Reactions Of Complex Systems, D. Rodjak, William Tobocman, Gaurav K. Tandon Oct 1972

One-Dimensional Three-Body Scattering Problem Used As A Testing Ground For The K-Matrix Method For Scattering Reactions Of Complex Systems, D. Rodjak, William Tobocman, Gaurav K. Tandon

Aerospace, Physics, and Space Science Faculty Publications

The scattering reactions of three equal-mass particles constrained to move in a straight line and interacting with each other via zero-range potentials have been analyzed on the basis of the extended R-matrix theory. The simplicity of the model facilitates an exposition of the complexities that result from the existence of rearrangement channels and from the possibility for breakup into three-body channels. The conventional expressions for the K matrix and the T matrix are derived on a rigorous basis. A practical method for approximating the continuum of three-body breakup channels by a discrete set is used to carry out a distorted-wave …

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