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On the development and applications of a three-dimensional ab initio cosmic-ray modulation model / Nicholas Eugéne EngelbrechtEngelbrecht, Nicholas Eugéne January 2012 (has links)
A proper understanding of the effects of turbulence on the diffusion and drift of cosmic-rays in
the heliosphere is imperative for a better understanding of cosmic-ray modulation. This study
presents an ab initio model for cosmic-ray modulation, incorporating for the first time the results
yielded by a two-component turbulence transport model. The latter model is solved for
solar minimum heliospheric conditions, utilizing boundary values chosen in such a way that
the results of this model are in fair to good agreement with spacecraft observations of turbulence
quantities, not only in the ecliptic plane, but also along the out-of-ecliptic trajectory of the
Ulysses spacecraft. These results are employed as inputs for modelled slab and 2D turbulence
energy spectra, which in turn are used as inputs for parallel mean free paths based on those
derived from quasi-linear theory, and perpendicularmean free paths from extended nonlinear
guiding center theory. The modelled 2D spectrum is chosen based on physical considerations,
with a drop-off at the very lowest wavenumbers commencing at the 2D outerscale. There currently
exist no models or observations for this quantity, and it is the only free parameter in this
study. The use of such a spectrum yields a non-divergent 2D ultrascale, which is used as an
input for the reduction terms proposed to model the effects of turbulence on cosmic-ray drifts.
The resulting diffusion and drift coefficients are applied to the study of galactic cosmic-ray
protons, electrons, antiprotons, and positrons using a three-dimensional, steady-state numerical
cosmic-ray modulation code. The magnitude and spatial dependence of the 2D outerscale
is demonstrated to have a significant effect on computed cosmic-ray intensities. A form for the
2D outerscale was found that resulted in computed cosmic-ray intensities, for all species considered,
in reasonable agreement with multiple spacecraft observations. Computed galactic
electron intensities are shown to be particularly sensitive to choices of parameters pertaining
to the dissipation range of the slab turbulence spectrum, and certain models for the onset
wavenumber of the dissipation range could be eliminated in this study. / Thesis (PhD (Physics))--North-West University, Potchefstroom Campus, 2013
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Cluster counting studies in a SuperB drift chamber prototypeDejong, Samuel Rudy 05 September 2012 (has links)
SuperB is a high luminosity e+e- collider experiment that is currently being designed to explore the flavour sector of particle physics. The detector at SuperB will contain a drift chamber, a gas filled device used to measure the momentum and identity of particles produced in the collisions. Particle identification in a drift chamber uses the measured amount of ionization deposited by the particle in the cells of the chamber, which provides a measurement of the particle speed. The ionization loss is traditionally measured by integrating the total charge released by the ionization after a gas amplification avalanche process. Since such a measurement has potentially large uncertainties associated with fluctuations in the gas amplification and other processes, it is possible that measuring the number of primary clusters of ionization caused by the particle could provide an improvement in the measurement of the ionization loss. The results of experiments performed at the University of Victoria and the TRIUMF laboratory M11 test beam using a SuperB drift chamber prototype to test the feasibility of counting clusters are presented here. The ability to separate muons and pions at the momenta explored in the TRIUMF testbeam was similar to the ability to separate pions and kaons at the higher momenta of SuperB. It was found that counting the clusters provides a significant improvement to particle identification when combined with the traditional measurement of the integrated charge. / Graduate
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Untersuchungen zur NOx-Einspeicherung an Ceroxid mittels IR-Spektroskopie in diffuser ReflexionPhilipp, Susanne. Unknown Date (has links)
Darmstadt, Techn. Universiẗat, Diss., 2007. / Dateien im PDF-Format.
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The late Quaternary environmental history of the Lake Heron Basin, Mid Canterbury, New Zealand : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Geology in the University of Canterbury /Pugh, J. M. January 2008 (has links)
Thesis (M. Sc.)--University of Canterbury, 2008. / Typescript (photocopy). One map in pocket. Includes bibliographical references (leaves 131-145). Also available via the World Wide Web.
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The sedimentology, morphology and evolution of Two Gravel Barachois, Placentia Bay, Newfoundland /Boger, Rebecca A., January 1997 (has links)
Thesis (M. Sc.)--Memorial University of Newfoundland, 1997. / Blbliography: leaves 278-293.
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Beiträge zur Sensorik redox-aktiver GaseKamp, Bernhard. January 2002 (has links)
Stuttgart, Univ., Diss., 2002.
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Understanding long-term beach width change in the Oceanside littoral cell, CaliforniaChenault, Carla D. January 2007 (has links)
Thesis (Ph. D.)--University of California, Santa Cruz, 2007. / Includes bibliographical references.
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Dynamics of the coupled ice-ocean system in the marginal ice zone study of the mesoscale processes and of constitutive equations for sea ice /Häkkinen, Sirpa. January 1984 (has links)
Thesis (Ph. D.)--Florida State University, 1984. / Typescript. Includes bibliographical references (leaves 91-95).
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Moving hotspots evidence from paleomagnetism and modelling /Antretter, Maria. Unknown Date (has links)
University, Diss., 2001--München.
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Sediment storage and delivery on Holocene glacial timescales, Granite Creek, southern Alaska /Blair, Mehgan O'Hearn. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2005. / Printout. Includes bibliographical references (leaves 48-52). Also available via the World Wide Web.
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