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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

Generating techniques in vacuum and stiff perfect fluid cosmologies

Kitchingham, David William January 1985 (has links)
No description available.
192

A study of gravitational properties of the Kaehler equation

Talebaoui, W. A. O. January 1987 (has links)
No description available.
193

Neighbourhood systems

Lok, R. W. January 1985 (has links)
No description available.
194

THE PROPAGATION OF ENERGETIC PARTICLES IN FINITE TEMPERATURE ASTROPHYSICAL PLASMAS.

DAVILA, JOSEPH MICHAEL. January 1982 (has links)
Solutions to the dispersion relation for waves propagating parallel to the static magnetic field in a plasma of arbitrary β are obtained. (β is the ratio of thermal to magnetic pressure.) Resonant scattering by these waves is evaluated. It is found that the magnetostatic approximation, used extensively in the past, breaks down for particles with pitch angles near 90°, and one must consider the more complicated process of particle scattering in electromagnetic turbulence. Many aspects of particle propagation in a finite temperature plasma can be discussed without assuming magnetostatic turbulence. This is accomplished by using a graphical method to obtain the solutions of the resonance condition. Results show that in a high β plasma, wave damping causes a gap, or hole, in μ-space where the resonant particle scattering rate is severely depressed. It is found that only high energy (γ ≥10⁵) electrons can be trapped within a typical supernova remnant. When the notion of electromagnetic resonance is applied to particle propagation in the interplanetary β ≤ 1) plasma, it is found that significant modifications to the conventional scattering picture must be made. It is found that a resonance gap exists which is similar to the one in a high β plasma. For electrons, this gap provides a natural explanation for scatter-free events. Theory predicts that these events should occur for kinetic energies T ≤ 300 keV while observations indicate that the majority have T ≤ 500 keV. For protons and energetic electrons, the scattering mean free path is critically dependent on the non-resonant scattering rate for particles within the gap. This fact provides a way to resolve the well known discrepancy between the theoretical and observational values for the mean free path, λ.
195

THE HYDRODYNAMIC EFFECTS OF NUCLEAR ACTIVE GALAXY WINDS ON HOST GALAXIES.

SCHIANO, ALLEN VINCENT ROGERS. January 1984 (has links)
In order to test the hypothesized existence of a powerful, thermal wind in active galactic nuclei, the hydrodynamic effects of such a wind on a model galactic interstellar medium (ISM) are investigated. The properties of several model ISMs are derived from observations of the Milky Way's ISM and those of nearby spiral and elliptical galaxies. The wind is assumed to be highly supersonic with spherical symmetry and constant mechanical luminosity, L(W). The propagation of the wind into the low density gas component of the ISM is studied using the Kompaneets approximation of a strong explosion in an exponential atmosphere. Flattened gas distributions are shown to experience "blow-out" of wind gas along the symmetry axis. The results show that for typical ISM gas pressures ( < 10⁻¹¹ ergs cm⁻³), the extent of the wind can range from 1 to 10 kpc for wind luminosities of 10⁴² to 10⁴⁶ ergs sec⁻¹ in a timescale of less than 10⁷ years. The steady state wind flow pattern and an estimate of the timescale required to reach a quasi-steady state are also determined. Next, the interaction of dense, interstellar clouds with the wind is investigated. The stability and mass loss of clouds in the wind are studied and it is proposed that clouds survive the encounter with the wind over large timescales ( >10⁷ yrs.). The physical structure and motion of the clouds are calculated, showing that large clouds (10³ solar masses) can be accelerated to velocities in excess of the galactic escape velocity. Finally, it is proposed that the Narrow Emission Line Regions (NELR) of active galaxies are the result of the interaction of active nuclei photons and a thermal wind on large, interstellar clouds. The physical state of the NELR is re-examined and shown to be compatible with this hypothesis. Arguments are presented to show that the NELR clouds must be massive and unable to be accelerated to NELR velocities by photon momentum alone. A Monte Carlo-type calculation is made to determine Narrow Emission Line profiles from an ensemble of photoionized interstellar clouds in the wind. These theoretical line profiles are shown to agree reasonably well with observed line profiles.
196

Urban design and enablement : a study on Indonesian inner city housing redevelopment

Siswanto, Andy January 2001 (has links)
No description available.
197

The influence of internal partitions on the air movement and contaminant dispersion in mechanically ventilated rooms

Lee, Heekwan January 2001 (has links)
No description available.
198

Developments in stylus profilometry

Yang, Ho Soon January 1999 (has links)
No description available.
199

New approaches and insights into simple molecular collisions

Whiteley, Thomas William James January 1998 (has links)
No description available.
200

Phase transitions in one dimensional random fields

Hope, Peter January 1988 (has links)
No description available.

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