Anglo-Irish relations in the framework of the EEC and Northern Ireland, 1969-1975

This thesis will analyse Anglo-Irish relations between 1969 and 1975, when two topics dominated the relationship: Northern Ireland and the entry of Britain and Ireland into the European Economic Community (hereafter EEC). In 1969 entry to the EEC was still only a possibility and awaited political developments, while the Northern Ireland problem had yet to escalate. 1975 on the other hand confirmed that Ireland would remain in the EEC even if Britain left while Direct Rule for Northern Ireland was confirmed as the British policy for the foreseeable future. These dates are significant because they encompass firstly pre and post entry to the EEC and how this transformed Anglo-Irish relations. Secondly they contain the commencement and then deterioration of the Northern Ireland problem and the attempts to resolve it that finally led to direct rule by Westminster. The study will examine the fluctuating nature of the relationship between Britain and Ireland. Special regard will be devoted to the demands of internal British politics and how such demands affected the relationship. Overall, the study will demonstrate how the bilateral relationship evolved under the pressure of events in Northern Ireland and adapted to the multilateral context of the EEC. It will compare the dynamics of the states’ interactions in two extremely different areas. The thesis will demonstrate how entry to the EEC transformed the unequal Anglo-Irish economic relationship and created one of partners within the EEC. It will also analyse how the developing Northern Ireland problem caused changes to British policy. In particular, it will examine how the British Government came to recognise the beneficial role that the Republic of Ireland might play in resolving the Troubles in Northern Ireland.

Magnetic materials and soft-switched topologies for high-current DC-DC converters

The thesis is focused on the magnetic materials comparison and selection for high-power non-isolated dc-dc converters for industrial applications or electric, hybrid and fuel cell vehicles. The application of high-frequency bi-directional soft-switched dc-dc converters is also investigated. The thesis initially outlines the motivation for an energy-efficient transportation system with minimum environmental impact and reduced dependence on exhaustible resources. This is followed by a general overview of the power system architectures for electric, hybrid and fuel cell vehicles. The vehicle power sources and general dc-dc converter topologies are discussed. The dc-dc converter components are discussed with emphasis on recent semiconductor advances. A novel bi-directional soft-switched dc-dc converter with an auxiliary cell is introduced in this thesis. The soft-switching cell allows for the MOSFET's intrinsic body diode to operate in a half-bridge without reduced efficiency. The converter's mode-by-mode operation is analysed and closed-form expressions are presented for the average current gain of the converter. The design issues are presented and circuit limitations are discussed. Magnetic materials for the main dc-dc converter inductor are compared and contrasted. Novel magnetic material comparisons are introduced, which include the material dc bias capability and thermal conductivity. An inductor design algorithm is developed and used to compare the various magnetic materials for the application. The area-product analysis is presented for the minimum inductor size and highlights the optimum magnetic materials. Finally, the high-flux magnetic materials are experimentally compared. The practical effects of frequency, dc-bias, and converters duty-cycle effect for arbitrary shapes of flux density, air gap effects on core and winding, the winding shielding effect, and thermal configuration are investigated. The thesis results have been documented at IEEE EPE conference in 2007 and 2008, IEEE APEC in 2009 and 2010, and IEEE VPPC in 2010. A 2011 journal has been approved by IEEE Transactions on Power Electronics.

Large magnetoelectric coupling in nanoscale BiFeO3 from direct electrical measurements

We report the results of direct measurement of remanent hysteresis loops on nanochains of BiFeO3 at room temperature under zero and ∼20 kOe magnetic field. We noticed a suppression of remanent polarization by nearly ∼40% under the magnetic field. The powder neutron diffraction data reveal significant ion displacements under a magnetic field which seems to be the origin of the suppression of polarization. The isolated nanoparticles, comprising the chains, exhibit evolution of ferroelectric domains under dc electric field and complete 180 switching in switching-spectroscopy piezoresponse force microscopy. They also exhibit stronger ferromagnetism with nearly an order of magnitude higher saturation magnetization than that of the bulk sample. These results show that the nanoscale BiFeO3 exhibits coexistence of ferroelectric and ferromagnetic order and a strong magnetoelectric multiferroic coupling at room temperature comparable to what some of the type-II multiferroics show at a very low temperature.