Structure has been observed in the stellar outflows of hot, luminous OB stars through the temporal spectral analysis of UV data: the absorption troughs of wind-accelerated P-Cygni profiles of certain UV ‘super-ions’, particularly the Pv λλ 1118, 1128 doublet, have revealed the presence of additional absorption components which have been observed to migrate through the wind. Similar P-Cygni profiles have also been observed in the the UV spectra of Central Stars of Planetary Nebulae (CSPNs), but detailed temporal analysis of CSPN outflows has been frustrated due to a lack of substantial time-series data. However, the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite has provided high-resolution time-series data for CSPNs, and therefore the nature of the time-variance of UV P-Cygni profiles can be investigated. To this end FUSE spectroscopic data has been obtained, and certain key UV resonance lines, as found in the stellar wind, have been subjected to various time-series analysis tools including Time Variance Spectra (TVS) and Fourier-based periodicity analysis. Also, optical time-series data of young CSPNs has been obtained via the ESO High-Accuracy Radial velocity Planetary Searcher (HARPS) spectrograph, and therefore similar temporal analysis has been carried out into the possible appearance of time-varying structure of Helium lines found in the deep photospheric regions of the atmosphere with the aim of detecting the presence of modulated structure at the base of the stellar wind – with the aim of discovering a causal mechanism for the higher wind-related phenomena. The presence of such structure in the stellar outflows of CSPNs (and likewise, OB stars) suggests that non-LTE stellar atmosphere analysis techniques – such as the Sobolev with Exact Integration (SEI) method used within this thesis – which assume a spherically smooth wind may provide inaccurate levels of mass loss from the stellar atmosphere; also, the possible non-smooth nature of the wind is considered from the viewpoint of possessing a more porous ‘clumped’ material which would also have an affect upon mass loss determinations, a key factor in the understanding of the latter stages of stellar evolution.

This thesis contains two separate bodies of research, both in terms of the period of time in which the work was done and their content, and as such is presented in two parts each of which are summarised below. The first part concerns work on entropy production in stochastic systems and describes the breakage of time reversal symmetry that arises in irreversible stochastic processes that one can associate with an entropy production contribution for a single realisation. The paradigm utilised is that of Markovian dynamics expressed using master equations and stochastic differential equations. By generalising some previously reported concepts so as to explicitly concern odd variables, some recent advances in non-equilibrium thermodynamics are refined which are then illustrated with several examples. The place of such results within the existing literature, particularly the extensive literature on fluctuation theorems, is emphasised allowing us to simultaneously demonstrate some of the widely celebrated symmetry relations to emerge from the field in recent years. The second part concerns the construction and implementation of a new Markov chain sampling algorithm called spatially local parallel tempering which improves the scaling of computational effort with system size of the well known thermal equilibrium sampling algorithm, parallel tempering. Parallel tempering accelerates thermal equilibrium sampling by performing regular sampling techniques on a composite system of replicas, each possessing a different temperature, and introducing configurational exchanges between those replicas so as to acquire configurations that would otherwise take a long time to reach. However, as the system size increases, the number of replicas required, and therefore computational effort, increases faster than linearly. To avoid this we propose local variations where this is not the case. We demonstrate these claims on several simple one dimensional models and show that the algorithms can reproduce thermodynamic accuracy in one and two dimensions.

This thesis reports the development of an instrument which could act as a future standard for Solar Irradiance. The instrument is called Cryogenic Solar Absolute Radiometer (CSAR), and it exploits the advances made in the field of cryogenic radiometry in the last few decades. The aim is to significantly reduce the measurement uncertainty as compared to the current standard (the World Radiometric Reference) and to guarantee the long-term stability of the measurement record. Several tests were carried out in order to verify the performance of CSAR. In a first test, CSAR was found to agree within 0.01% with the National Physical Laboratory’s SI standard for radiant power. In a second test, CSAR and the World Radiometric Reference were compared on the World Radiation Center’s solar tracker in Davos/Switzerland. In this comparison, the World Radiometric Reference measured 0.309% higher than CSAR; the relative standard uncertainty of the comparison was 0.028%. This difference between the current Solar Irradiance standard and CSAR is able to explain the offset between the two space experiments VIRGO/SOHO and TIM/SORCE. The CSAR result is further confirmed by the fact that a similar offset between the World Radiometric Reference and the SI-scale has been determined through experiments independently performed at the Laboratory for Atmospheric and Space Physics (University of Colorado Boulder). CSAR has also been designed with space flight in mind. Although no full evaluation of the space-worthiness has been carried out, thermal tests indicate that CSAR could cope with the limited cooling power provided by readily available space coolers. The relative standard uncertainty of space-based Total Solar Irradiance measurements by CSAR is estimated to be 0.011%.

Up to now, the market of solar cells has been dominated by the conventional silicon devices. Recently, a new class of solar cells, known as dye-sensitised solar cells (DSSCs) have emerged. They are based on the hybrid chromophore/TiO2 semiconductor interface, and the low cost of manufacturing and the flexibility make them a very promising alternative to the traditional silicon cells. With this thesis, we aim at investigating theoretically, by means of density functional theory atomistic simulations, some of the current challenges in DSSCs. In particular, we will focus on the binding mode of the most common anchoring groups to TiO2, the coating of TiO2 with a second oxide such as Al2O3 to increase the efficiency, the issues related to the island growth mode during the atomic layer deposition of Al2O3 on TiO2, and the use of the delta self-consistent field method for the excitations of natural anthocyanidins. The idea is to provide experimentalists with useful guidelines for the design of devices with improved efficiencies.

The principal aim of this research was to assess at-line Near Infrared Spectroscopy (NIRS) to support Process Analytical Technology (PAT) applications within solid dosage form manufacturing. The history of PAT was traced from implementation of process analytical applications prior to the 2003 United States, Food and Drug Administration PAT initiative through to current time. The use of NIRS within the PAT context was reviewed, highlighting two areas in solid dosage manufacturing where further research of at-line NIRS is warranted; material testing and finished dosage form analysis. Novel applications of at-line NIRS were investigated and developed aligned with the PAT philosophy, to establish an innovative system of analysis that combined chemometrics and spectral analysis with statistical process control (SPC). In particular, various chemometric algorithms were explored to enable rapid monitoring of global spectral quality as well as the quality of specific critical-to-process material attributes within a SPC framework. Novel approaches to within and between batch SPC for tablet quality conformance were also developed including the adaption of distribution profile control charts typically applied to particle size measurement. These were quick to develop with greatly reduced reliance on reference analysis. It provided an opportunity for extensive process monitoring and in-depth process understanding. The work highlighted gaps in currently available chemometric and SPC capabilities within NIR instrument control software and provided insight into a new direction for NIRS analysis in the future. The new conformance methodology was demonstrated to provide business value and critical science based understanding of the pharmaceutical formulation and processes with successful application of the methodology at a commercial Pfizer facility. This methodology is in the process of rolling out worldwide. The approach was found to be approachable for plant operators through to quality analysts, and is broadly applicable with the potential to extend beyond the solid dosage form studied.

This thesis concentrates on the development of a process-chain for the manufacture of the mirror segments for the European Extremely Large Telescope (E-ELT). This revolutionary scientific project with a 39.3m primary mirror will be the largest optical/near-infrared telescope in the world. The primary mirror design consists of 798 aspheric hexagonal segments, each 1.44 metres across-corners, but only 50mm thick. The manufacture of these aspheric segments poses many challenges. Edge mis-figure is regarded as one of the most difficult technical issues for segment production, impacting directly on the telescope’s science output, such as the detection of extrasolar terrestrial planets. The other challenge is how to speed up the process for the manufacture of almost 1000 segments in a reasonable time and cost. The 'Precessions' polishing technique is an advanced polishing method with high precision and efficiency. To achieve the specification of E-ELT’s segments, there are some key techniques that need to be researched, such as: edge control, removal of mid-spatial frequency errors and a massive improvement in process speed c.f. classical methods. The research work in this thesis contributed to the delivery of an effective process, including the characterisation of tool influence functions for the 'Precessions' technique; optimisation of the process parameters; edge control; diagnoses of edge asymmetry of hexagonal parts, and speeding-up the whole process. Two process-chains giving substantially different depths of removal have been developed and demonstrated on a hexagonal Zerodur part (200mm across-corners) with edge control, and the results meet the E-ELT specification. As a result, different top-level strategies for addressing the manufacture have been considered, leading to a preferred direction for the research.

The subject of this thesis explores the development of magnetic hyperthermia technology at the preclinical stage. Magnetic hyperthermia uses magnetic nanoparticles as functionalisable agents, targeted to cancer sites. They can then be non-invasively activated by alternating magnetic fields to deliver lethal doses of heat to the cancer cells with minimal damage to healthy tissue. This work concentrates on several complex aspects concealed within the conceptual simplicity of magnetic hyperthermia. One key aspect lies in the design of the alternating magnetic field generator. Here, a novel device, the MACH system, that exceeds currently available AC magnetic field generators in performance, form factor and versatility is described and evaluated. Electronic characteristics for 5 different configurations, ranging from a solenoidal to a flat applicator, are presented. Furthermore, magnetic field distributions in and around the applicator coil were modeled for all real configurations and two hypothetical models. These models revealed that in certain configurations high magnetic field gradients exist, prompting careful positioning of samples in real experiments. Sixteen commercially available iron-oxide nanoparticles with potential as hyperthermia candidates were characterised using photon correlation spectroscopy, atomic emission spectroscopy, asymmetric field-flow fractionation, spectrophotometric iron trace analysis, calorimetric analysis and magnetometry. To compare the heating rates of nanoparticle samples, a new design rule parameter, the intrinsic loss parameter (ILP), was introduced to replace the status quo, the equipment-dependent specific absorption rate (SAR). The results highlight a magnetic crystal size dependence with ILP, and also imply that some commercial samples are approaching the best achievable results. Finally, the commercial potential of the MACH system is evaluated in light of new applications that exploit its unique, distinguishing features. Hyperthermia cancer treatment was concluded to have the greatest potential on the long run, with the adhesives and thermoset polymer industry being lucrative short-term targets.

The calibration of the calorimeter energy scale is vital to measuring the mass of the W boson at CDF Run II. For the second measurement of the W boson mass at CDF Run II, two independent simulations were developed. This thesis presents a detailed description of the modification and validation of Bremsstrahlung and pair production modelling in one of these simulations, UCL Fast Simulation, comparing to both GEANT4 and real data where appropriate. The total systematic uncertainty on the measurement of the W boson mass in the W \rightarrow ev_{e} channel from residual inaccuracies in Bremsstrahlung modelling is estimated as 6.2 \pm 3.2 MeV/c ^{2} and the total systematic uncertainty from residual inaccuracies in pair production modelling is estimated as 2.8 \pm 2.7 MeV/ c^{2}. Two independent methods are used to calibrate the calorimeter energy scale in UCL Fast Simulation; the results of these two methods are compared to produce a measurement of the Z boson mass as a cross-check on the accuracy of the simulation.

This thesis presents a study of ionised outflows and multi-wavelength variability of Active Galactic Nuclei (AGN) focusing on three Seyfert-type objects: NGC 3516, Mrk 509 and ESO 113-G010. For this work I have made use of mostly XMM-Newton data, i.e. high-resolution X-ray spectra from the Reflection Grating Spectrometer (RGS) for exploring the ionised outflows, and simultaneous optical/UV/X-ray data from the Optical Monitor (OM) and the European Photon Imaging Camera (EPIC) instruments to study the intrinsic emission and variability. I have investigated the structure and geometry of the partial-covering multi-phase ionised absorber of NGC 3516. I demonstrate that the X-ray variability, originally attributed to occultation by a cloud in an accretion disc wind passing in front of the source, is rather the result of changes in the intrinsic emission of the source. From a 100-day multi-wavelength campaign on Mrk 509, I find that the character of its variability, strictly correlated in the UV and soft X-ray bands, indicates that the soft X-ray excess emission is produced by Compton reprocessing of the UV disc emission in a warm corona encasing the inner disc. I have also studied the nuclear obscuration and the role of dust in the warm absorber of ESO 113-G010. I show that the cause of significant optical/UV reddening, despite the lack of X-ray absorption from neutral gas, is most likely to be dust embedded in a weakly-ionised phase of an absorber which is conspicuous in the high-resolution X-ray spectrum of this object. I have explored the uncertainties in the irradiating spectral energy distribution due to the nuclear obscuration of the source and the effects these have on the survival of the dust, on the thermal stability of the warm absorber phases and the ionisation balance calculations required for photoionisation modelling. From my case-studies of these three objects emerges a more detailed picture of the ionised outflows phenomenon and of the environment in the vicinity of the nuclear supermassive black holes in AGN.

We present a study of the manipulation of micro-particles and the formation of optically bound structures of particles in evanescent wave traps. Two trapping geometries are considered: the first is a surface trap where the evanescent field above a glass prism is formed by the interference of a number of laser beams incident on the prism-water interface; the second uses the evanescent field surrounding a bi-conical tapered optical fibre that has been stretched to produce a waist of sub-micron diameter. In the surface trap we have observed the formation of optically bound one- and two-dimensional structures of particles and measured the binding spring constant by tracking particle motion and the extent of the particle’s Brownian fluctuations. Additionally, we have measured the inter-particle separations in the one-dimensional chain structures and characterised the geometry of the two-dimensional arrays. In the tapered optical fibre trap we demonstrated both particle transport for long distances along the fibre, and the formation of stable arrays of particles. We present the fabrication of tapered optical fibres using the 'heat-and-pull` technique, and evanescent wave optical binding of micro-particles to the taper. Calculations of the distribution of the evanescent field surrounding a tapered fibre are also presented. We show that the combination of modes can give control over the locations of the trapping sites. Additionally, we show how the plasmon resonance of metallic nano-particles can be exploited to enhance the optical trapping force, and suggest how a bi-chromatic nano-fibre trap for plasmonic particles may be implemented. In both experiments we implement video microscopy to track the particle locations and make quantitative measures of the particle dynamics. The experimental studies are complemented by light scattering calculations based on Mie theory to infer how the geometries of the particle structures are controlled by the underlying incident and scattered optical fields.