Constantly increasing demand for electrical power requires more efficient and more powerful machines to be built. The conventional technology cannot provide such machines. It cannot deliver machines that are smaller, lighter and provide larger torques and power ratings. The answ…
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Considerable amount of transmission and distribution of electricity is carried out by power cable. At present, most high voltage direct current (HVDC) installation uses traditional (oil-impregnated paper insulation and oil-filled-types) cables which pose a risk of environmental …
Studies into sonoporation and electroporation have grown rapidly in biotechnology and medicine in recent years. This research presents a microfluidic system for cell transfection using sonoporation and electroporation. This research has studied, designed, developed and tested th…
In order to achieve high speed and packing density, the size of the transistor has shrunk aggressively. The gate dielectric, as the most critical component in the transistor, is undergoing rapid and substantial changes with the adoption of ultra-thin plasma nitrided oxide and mo…
In this thesis, the dye molecule cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato)-ruthenium(II) (N3) is studied on the rutile TiO2(110) and Au(111) surfaces. The molecules were deposited onto the surfaces using an ultra-high vacuum (UHV) electrospray deposition syst…
This thesis describes the development of a sensorless control method for a surface mounted permanent magnet synchronous machine drive system. The saturation saliency in the machine is tracked from the stator current transient response to the fundamental space vector PWM (pulse w…
STATCOM (STATic COMpensator) has been used in electrical power systems as a shunt-connected compensator for voltage support and to improve power quality. Compared with the conventional compensators such as the synchronous condenser and the SVC (Static Var Compensator), the STATC…
Digital Pulse Position Modulation (digital PPM) is a modulation format that codes n bits of PCM into a single pulse that occupies one of 2n time slots. Various studies over the last three decades have shown that such a scheme can offer an improvement in receiver sensitivity of 5…
Semiconductor Seeded Fibre Amplified Sources of Ultra Short Pulses By Stephen Paul Elsmere This thesis reports upon an experimental investigation of passively mode-locked optically pumped vertical-external-cavity surface-emitting semiconductor lasers (VECSEL). Mode-locked VECSEL…
High Harmonic Generation is a highly nonlinear process that can be used to generate a high flux, low divergence, coherent beam in the extreme ultraviolet (XUV) wavelength range. It is proposed that this radiation source could be implemented for microscopy using coherent diffract…
This work is related to the investigation and development of novel concepts to utilise planar nanostructures in optics, aided by complementary research in the microwave domain—in particular: Strong polarisation conversion capabilities are shown for planar chiral nanoholes in the…
In this thesis I investigate optical properties of metre - long tapers. Microstructured optical fibre technology has created new opportunities in a broad range of science and technology. In the work presented in this thesis I have combined the microstructured optical fibre techn…
Electromagnetic metamaterials are artificial media that derive novel properties from periodic structuring on the sub-wavelength scale. Here, the consequences of two-dimensional (2D) and three-dimensional (3D) chirality for the electromagnetic properties of metamaterials are inve…
Intrinsic parameter fluctuations have become a serious obstacle to the continued scaling of MOSFET devices, particularly in the sub-100 nm regime. The increase in intrinsic parameter fluctuations means that simulations on a statistical scale are necessary to capture device param…
The general demand for automating industrial processes in the oil industry has increased rapidly in parallel with sensors and their underlying technology. Since the early 1980s, the particular problem, which has been representing the extremes in complexity in the oil industry, i…
Today the majority of UK's energy needs are met by fossil fuels. An energy sector that uses 30% of this energy and generates 28% of the total emissions is domestic sector. To reduce the emissions generated by fossil fuels UK government decided to increase the energy coming from …
This work considers the sensorless control of AC machines for the low and zero speed operation range. Two novel techniques have been developed that use the inherit nature of the inverter PWM to estimate the rotor position of the machine. The inherent back EMF and the saliency of…
There is increasing demand for simple motor drives offering high reliability and fault tolerance in applications such as the aerospace actuator industry, with the development of `more electric aircraft'. This thesis presents a motor drive employing a switched reluctance motor, t…
This thesis concerns the modified and improved, time-stepping, dynamic reluctance mesh (DRM) modelling technique for machines and its application to multiple machine systems with their control algorithms. Improvements are suggested which enable the stable solution of the resulti…