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Showing 1 to 20 of 48 for “"F300 - Physics"”.
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Anisotropic behaviour of magneto-electric coupling in multiferroic composites
The anisotropy of the direct magnetoelectric effect in textured nickel ferrite/lead zirconate titanate strain mediated bilayer composites has been studied. The magnetic layers of these samples have been crystallographically textured in planes of the form {100}, {110} and {111}. In this study, it is …
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Remanent state noise in particulate magnetic recording media
Remanent state noise is the variation in stray flux emanating from a magnetic recording medium which is in a remanent state of magnetisation. A portion of this noise is related to the magnetic microstructure of the recording medium. This study had two main objectives. The first was to devise and …
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Non-isocyanate routes to urethane-polymers
The conventional synthetic route to urethane polymers involves the use of hazardous dflsocyanates which are synthesised using phosgene, the use of which produces a significant chlorine-waste stream. The processing of high molecular mass specialty polyurethanes regularly requires the use of organic …
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Counterion identity effects on the self-assembly processes in a series of perfluorinated surfactant - water mixtures
The effects of counterion on the lyotropic liquid crystalline phase behaviour of some quaternary ammonium salts of perfluorodecanoic acid in water have been studied using a combination of optical polarising microscopy (OPM), deuterium nuclear magnetic resonance (211 NMR) and cryo-transmission …
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Structural studies of nonionic lyotropic liquid crystals
The nonjonic surfactants n-C 1 6113 3 (OCH2CH2) 60H (C 1 6E06 ) and CiS-C9H18=C 1 3H2 5 (0CH2CH2 ) 60H (C22E06) have been studied in binary mixtures with heavy water, using techniques including optical microscopy, nuclear magnetic resonance and x-ray and neutron scattering. The liquid crystalline …
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Molecular self assembly in flurocarbon surfactant / water systems
The work presented is a continuation of the study of a homologous series of tetrabutylammonium perfluoroalkylcarboxylate surfactants in water. These systems showed phase behaviour uncharacteristic of ionic perfluorocarbon surfactant systems in that they exhibit a clouding phenomenon with increasing …
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Computer-aided design and synthesis of 5,7-dihydroxyflavone derivatives as glycogen phosphorylase inhibitors
Diabetes is a chronic disease that affects approximately 415 million people worldwide and this number is expected to rise to 642 million by the year 2040. 90% of cases of diabetes are type 2. Although some treatments are already available for type 2 diabetes, there are considerable side-effects …
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Cathodoluminescence of radiation damage, non-stoichiometric and impurity defects in cadmium telluride
The effects of atomic displacement, degree of nonstbichiometry and impurity doping on the liquid helium temperature cathodoluminescence of cadmium telluride have been investigated. Under such treatment the responses of the emissions have cast some doubt on the previously accepted significance of …
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Transverse susceptibility measurements on particulate recording media
An experimental investigation of transverse susceptibility (Xi) measurements on particulate recording media has been made. The main use of this measurement is to determine the anisotropy field (Ilk) of a material which is one of its intrinsic properties. Previous theoretical modelling of Xi was …
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Flux pinning in superconducting Pb-Na
Some of the reversible properties of type II superconductora are considered in tens of the Ginzberg-Landau equations. The discussion is extended to consider flux pinning in the bulk and on the surface in the mixed state. The apparatus used to measure the a.c. flux penetration into a Pb-Na …
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The relationship between the structure and physical properties of acylhydrazinatometallomesogens
Series of novel thermotropic metallomesogenic complexes have been synthesised and their liquid crystalline phases characterised. Anomalous in-plane packing of the molecules in all phases, namely two diffuse in-layer features, is observed by x-ray scattering. The first, at 16A, compares to a …
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Theoretical studies of strongly interacting fine particle systems
A theoretical analysis of the time dependent behaviour of a system of fine magnetic particles as a function of applied field and temperature was carried out. The model used was based on a theory assuming Neel relaxation with a distribution of particle sizes. This theory predicted a linear variation …
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Magnetisation reversal in permanent magnet materials
This thesis presents an investigation of the reversal of magnetisation in sintered anisotropic Nd-Fe-B, isotropic melt-spun Nd-Fe-B powder, and in Sm-(Co,Cu,Fe,Zr) 2:17 anisotropic powder. Magnetisation measurements have been performed using vibrating sample magnetometers, a permeameter, and an …
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Steiner triple systems and cycle structure
Since 1847 when Rev. T.P. Kirkman published his first paper [24], research in Steiner triple systems has grown steadily. With increased and ready access to more powerfiul computers in recent times, this growth has accelerated significantly. Problems are now being solved which were previously …
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An x-ray scattering study of surfactant water mixtures
The occurrence of nematic and lamellr mesophases in concentrated surfactant / water mixtures is a well documented phenomenon. This work examines the structure and order of the mesophases exhibited by two sample systems, caesium pentadecafluorooctanoa-te (CsPFO) / heavy water, and decylammonium …
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Multifrequency monitoring of blazars
The work presented in this thesis summarises the research carried out by the author. As an introduction, the variability of blazars is described and the various models believed to be responsible for the emission mechanisms which power these objects are discussed. The core blazars which have been …
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Micomagnetic calculations of the magnetic properties of thin metallic films
A micromagnetic model has been developed to simulate the magnetisation in a metallic thin film. This is achieved by energy minimisation techniques. The energy of each grain in the medium includes Zeeman, anisotropy, magnetostatic and exchange. The magnetostatic energy is incorporated by considering …
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Spin dynamics of fine magnetic particles
A computer model of fine magnetic particles has been developed based on the Landau-Lifshitz equation. It is a dynamic model which allows the detailed behaviour of the magnetic moments during magnetisation changes to be investigated. The model was initially used to study gyroremanent magnetisation …
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The effect of Adiabatic compression on the fundamental plane of bulges
This project has used scaling relations and the Fundamental Plane to investigate the phenomenon of bulge compression. Bulge compression takes place as disks grow around bulges. When the bulge is compressed the velocity dispersion of the bulge increases, according to the Virial theorem. This project …
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The Effects of Radial Migration on the Outskirts of Disc Galaxies
Since the discovery of radial migration a galaxy can no longer be considered to be a collection of annuli evolving in isolation. Previous works have considered the implications of migration on properties of disc galaxies, but most of these efforts concentrate on the Solar neighbourhood, where …
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