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Spero, R.E.

California Univ., Irvine (USA)

California Univ., Irvine (USA)

AbstractAbstract

[en] A laboratory test of the inverse square law of gravity has been conducted. The almost null field inside a long precisely machined tube was probed by a test mass suspended from a torsion balance. In terms of a distance-dependent gravitational constant G(r), the experiment is sensitive to variations in G(r) over the distance range of approximately 2 to 5 cm. If G(r) = G

_{0}[1 + epsilon In r(cm)], epsilon is found to be (1 +- 7) x 10^{-5}, in support of the inverse square lawPrimary Subject

Source

1980; 139 p; University Microfilms Order No. 80-08,450; Thesis (Ph. D.).

Record Type

Report

Literature Type

Thesis/Dissertation; Numerical Data

Country of publication

Publication YearPublication Year

Reference NumberReference Number

INIS VolumeINIS Volume

INIS IssueINIS Issue

AbstractAbstract

[en] The integral energy method has been used in order to study the large-scale coherent wave mode interactions in a spatially developing round jet of a large Reynolds number. A flow quantity is split into two components; time-independent mean flow and large-scale coherent structure. The large-scale structure is decomposed into three fundamental wave modes (axisymmetric, first-order and second-order helical) and two subharmonic modes (axisymmetric and first-order helical). The streamwise development of a jet is obtained in terms of the mean flow shear layer momentum thickness, the wave mode kinetic energy and the wave mode phase angle. The results of the five mode interaction show that the axisymmetric and helical modes grow almost identically in the initial region until the energy densities of the fundamental modes reach peak values. When the initial energy density of one wave mode is much higher than those of the other modes, the other wave modes do not affect the streamwise development of the mean flow and the forced mode until the energy density of the forced mode reaches a peak value. The jet development also can be predicted by two wave modes (fundamental and subharmonic) if their initial energy densities are much higher than those of the others

Primary Subject

Secondary Subject

Source

1988; 311 p; Brown Univ; Providence, RI (USA); University Microfilms, PO Box 1764, Ann Arbor, MI 48106, Order No.88-22,548; Thesis (Ph. D.).

Record Type

Miscellaneous

Literature Type

Thesis/Dissertation; Numerical Data

Country of publication

Publication YearPublication Year

Reference NumberReference Number

INIS VolumeINIS Volume

INIS IssueINIS Issue

Porter, A.C.

California Inst. of Tech., Pasadena, CA (USA)

California Inst. of Tech., Pasadena, CA (USA)

AbstractAbstract

[en] This thesis presents ellipse-fitting isophotometry of 175 brightest elliptical galaxies in Abell clusters (BDEs). Galaxy structure is traced to an average major axis of 50 kpc, and sometimes beyond 100 kpc. The data consist not only of major and minor-axis surface brightness profiles, but also of isophote ellipticity, major axis position angle, and centroid position profiles. Almost all BCEs have some local structure that does not show in an azimuthally averaged brightness profile. However, local structure shows no correlation with global parameters such as galaxy luminosity or size. These results echo similar earlier findings for field ellipticals. An analytic method for separating the light distributions of overlapping binary galaxies has been derived and applied to 12 such systems. It is based solely on the assumption that each galaxy in the pair has point-reflection symmetry about its own center. Nonconcentric light is a probe of interactions between the members of the pair

Primary Subject

Secondary Subject

Source

1988; 472 p; California Institute of Technology; Pasadena, CA (USA); University Microfilms, PO Box 1764, Ann Arbor, MI 48106, Order No.88-20,983; Thesis (Ph. D.).

Record Type

Miscellaneous

Literature Type

Thesis/Dissertation; Numerical Data

Country of publication

Publication YearPublication Year

Reference NumberReference Number

INIS VolumeINIS Volume

INIS IssueINIS Issue

Karabali, D.

Yale Univ., New Haven, CT (USA)

Yale Univ., New Haven, CT (USA)

AbstractAbstract

[en] Certain nonperturbative phenomena appearing in two specific (2 + 1) dimensional models are studied. The phenomenon of fractional spin and exotic statistics in (2 + 1) dimensions is analyzed in the context of a specific field theoretic model, namely the (2 + 1) dimensional 0(3) nonlinear sigma model, with a topological action, the Hopf term. It admits solitons, which acquire fractional spin, due to the topological term in the action. Canonical quantization methods are used to determine the fractional spin in terms of the topological charge Q of the solitons and the coefficient Θ of the Hopf term. A semiclassical quantization in terms of collective coordinates in the Q = 1 sector is also carried out. The current algebra of the model is constructed and it is argued that the coefficient Θ can be understood as a parameter labeling different representations of the current algebra. The nonperturbative phenomenon of dynamical symmetry breaking is analyzed in the context of the (2 + 1) dimensional massless quantum electrodynamics with N species of fermions, treated in a 1/N expansion. The model exhibits a chiral symmetry which is spontaneously broken by dynamically generated fermion masses. The Dyson-Schwinger equations for the model are studied and it is shown that there exist symmetry breaking solutions

Primary Subject

Secondary Subject

Source

1986; 99 p; Yale Univ; New Haven, CT (USA); University Microfilms, PO Box 1764, Ann Arbor, MI 48106, Order No.87-28,146; Thesis (Ph. D.).

Record Type

Miscellaneous

Literature Type

Thesis/Dissertation; Numerical Data

Country of publication

Publication YearPublication Year

Reference NumberReference Number

INIS VolumeINIS Volume

INIS IssueINIS Issue

AbstractAbstract

[en] The direct imaging channel of the Princeton CCD spectrometer has been used to obtain four-color broadband photometry of two distant clusters of galaxies. The observations have been made as part of a search for evidence of galactic evolution. Data reduction techniques have been developed to extract photometric information from small images of low surface brightness. These techniques have been applied to obtain broadband colors in the spectral range between 5000 and 9000 Angstroms down to a limiting apparent visual magnitude of about 21.5. The observed colors show no evidence for the presence of substantial numbers of young blue stars. There is some evidence for an anomalously broad distribution of color in the spectral range between 7000 and 9000 angstroms

Primary Subject

Source

1980; 142 p; University Microfilms Order No. 80-16,163; Thesis (Ph. D.).

Record Type

Report

Literature Type

Thesis/Dissertation; Numerical Data

Country of publication

Publication YearPublication Year

Reference NumberReference Number

INIS VolumeINIS Volume

INIS IssueINIS Issue

Farawila, Y.M.

Wisconsin Univ., Madison (USA)

Wisconsin Univ., Madison (USA)

AbstractAbstract

[en] The problem addressed in this thesis research is the accurate evaluation of neutron fluence-to-kerma (Kinetic Energy Released in Materials) factors from microscopic nuclear data. The algorithms developed for this purpose combine in a consistent manner the two basic methods for computing kerma factors, namely kinematics and direct energy balance. These algorithms are implemented in the code KAOS-V which was used as the main evaluation tool to construct the response function library KAOS/LIB-V. The library contains kerma factors and other nuclear response functions for 43 nonfissionable and 15 fissionable isotopes and elements. The chief source of data is the evaluated nuclear data files ENDF/B-V. Auxiliary nuclear data bases, e.g., the Japanese evaluated nuclear data library JENDL-2 were used as a source of isotopic cross sections when these data are not provided in ENDF/B-V files for a natural element. These are needed mainly to estimate average quantities such as effective Q-values for the natural element. This analysis of local energy disposition was instrumental in detecting and understanding energy-balance deficiencies and other problems in the ENDF/B-V data

Primary Subject

Source

1987; 227 p; University Microfilms Order No. 87-23,328; Thesis (Ph. D.).

Record Type

Report

Literature Type

Thesis/Dissertation; Numerical Data

Country of publication

Publication YearPublication Year

Reference NumberReference Number

INIS VolumeINIS Volume

INIS IssueINIS Issue

Greenwood, W.G.

Oregon State Univ., Corvallis (USA)

Oregon State Univ., Corvallis (USA)

AbstractAbstract

[en] Frequency distributions are calculated for the optical decay of two atomic states coupled by a strong, linear rf field. Both the rotating and the counter-rotating components of the field are maintained throughout the calculations. For strong fields many peaks are present in the frequency spectrum, and are explained in terms of decay from dressed atomic states. These calculations are compared with frequency distributions for a rotating rf field and with the lowest-order approximation for a linear rf field. The energy levels of the dressed atomic states are derived from the locations of the peaks in the frequency distribution. The Bloch-Seigert shifts of the resonances for the excited states are calculated as a function of the rf field strength. The calculated results for the Bloch-Siegert shifts and for the emitted distribution of frequencies are compared with recent experimental results

Primary Subject

Source

1978; 210 p; University Microfilms Order No. 78-21,386; Thesis (Ph. D.).

Record Type

Report

Literature Type

Thesis/Dissertation; Numerical Data

Country of publication

Publication YearPublication Year

Reference NumberReference Number

INIS VolumeINIS Volume

INIS IssueINIS Issue

Pirkle, D.R.

Wisconsin Univ., Madison, WI (USA)

Wisconsin Univ., Madison, WI (USA)

AbstractAbstract

[en] The gas flow characteristics of a novel geometry (pumped neutralizer) for decreasing the flow of gas from neutral beam neutralizers were measured and compared with a conventional (passive) neutralizer. A passive neutralizer is typically a duct attached to the ion source. For the pumped neutralizer the top and bottom surfaces of the duct are replaced by a Venetian blind geometry which opens into ball as vacuum pumping volumes. With guidance from a Monte Carlo program which models gas flow at low pressure, a one-half scale model with pumped neutralizer geometry was built and compared to a passive neutralizer with comparable dimension. With the vanes on the pumped neutralizer opened to 55 degrees, the line density of the pumped neutralizer was 1.6 times less than the passive neutralizer. The amount of gas flowing from the exit of the pumped neutralizer was from 2 to 5 times less than the amount flowing from the pumped neutralizer. Hence,the pumped neutralizer geometry appears to be a promising method of limiting the flow of gas from neutral beam gas cell neutralizers

Primary Subject

Secondary Subject

Source

1984; 159 p; Univ. of Wisconsin; Madison, WI (USA); University Microfilms, PO Box 1764, Ann Arbor, MI 48106, Order No.84-10,792; Thesis (Ph. D.).

Record Type

Miscellaneous

Literature Type

Thesis/Dissertation; Numerical Data

Country of publication

Publication YearPublication Year

Reference NumberReference Number

INIS VolumeINIS Volume

INIS IssueINIS Issue

Kawano, L.

Fermi National Accelerator Lab., Batavia, IL (USA)

Fermi National Accelerator Lab., Batavia, IL (USA)

AbstractAbstract

[en] The evolution of domain walls in the early universe is studied via 2-D computer simulation. The walls are initially configured on a triangular lattice and then released from the lattice, their evolution driven by wall curvature and by the universal expansion. The walls attain an average velocity of about 0.3c and their surface area per volume (as measured in comoving coordinates) goes down with a slope of -1 with respect to conformal time, regardless of whether the universe is matter or radiation dominated. The additional influence of vacuum pressure causes the energy density to fall away from this slope and steepen, thus allowing a situation in which domain walls can constitute a significant portion of the energy density of the universe without provoking an unacceptably large perturbation upon the microwave background

Primary Subject

Source

Oct 1989; 30 p; NASA-CR--186076; NAS--1.26:186076; FERMILAB-PUB--89/208-A; NTIS, PC A03/MF A01; Ph.D. Thesis - Chicago Univ.

Record Type

Report

Literature Type

Thesis/Dissertation; Numerical Data

Report Number

Country of publication

Publication YearPublication Year

Reference NumberReference Number

INIS VolumeINIS Volume

INIS IssueINIS Issue

AbstractAbstract

[en] The flux shielding characteristics of NbTi alloy tubes are investigated in both axial and transverse applied fields by a field mapping technique using miniature Hall generators. Bulk Nb65w/oTi tubes without cold work are shown to be able to exclude axial applied fields of over 1.73 tesla and transverse applied fields of up to 0.52 tesla. A jelly-roll tube of NbTi and Cu is successful in shielding a transverse field of 0.72 tesla without flux jumps. The distribution of shielding supercurrents in the tube wall are analytically derived from the field profile measured inside or around the flux exclusion tube. It is found that the induced supercurrents in an axial applied field always concentrate near the tube ends and cause these end areas to be prone to partial or complete flux jumps. The effectiveness of the critical state concept and Kim's critical current model is fully verified in our NbTi alloy tubular system. A phenomenological model of the supercurrent distribution in the tube wall is proposed to interpret the experimental results in the transverse fields. The influence of alloy composition and heat treatments on the shielding performance of NbTi alloy tubes is experimentally studied

Primary Subject

Secondary Subject

Source

1983; 201 p; University Microfilms Order No. 84-00,525; Thesis (Ph. D.).

Record Type

Report

Literature Type

Thesis/Dissertation; Numerical Data

Country of publication

Publication YearPublication Year

Reference NumberReference Number

INIS VolumeINIS Volume

INIS IssueINIS Issue

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