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The work of instructional design in community college settings is woefully understudied. This study documents that work in three community colleges in the southeastern United States while placing it in the theoretical context of neoliberalism, and in line with that theoretical context, takes a post-structuralist stance in its methodological approach. It is in the discourses of instructional quality, online teaching, and design that instructional designers and faculty engage with each other. In contrast to the more well understood working relationship in a four-year institution, the power relationships between these two groups have not been examined in a community college context. Therefore, the research questions for this study were: (1) What practices do instructional designers and faculty employ in negotiating the boundaries and responsibilities of teaching and design in a community college context?; and (2) How do power/knowledge relations produce instructional designers' and faculty's multiple subjectivities as they engage in the development and teaching of online courses? To investigate these questions, instructional designers, managers, and faculty were interviewed, with the instructional designers being interviewed multiple times over a number of months in the first half of 2023. One of the findings of the study was that instructional design as a practice is making institutional space for itself by unbundling the role of faculty, and the definition of what a course is. In this process, Quality Matters as a certifying organization has emerged as a mechanism by which instructional designers identify themselves as professionals within institutions, with areas of specialized expertise. Among the curiosities that emerged from this study, the mutual invisibility of work appeared to function in keeping people apart and in tension with one another. Everybody was busy, unappreciated, and unacknowledged, but "others," particularly faculty, were characterized as not "good workers" or out of touch and living in a dream world. This suggested that an intentional orientation toward hopeful futures through speculative fiction (hopepunk) might offer a way forward. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]

Mineral dust is one of the most abundant atmospheric aerosols and has a wide range of impacts on climate, meteorology, health and biogeochemistry. North African sources are responsible for about half of the total atmospheric burden, peaking as an emission source in the boreal summer months of June, July and August. In-situ data from the Fennec observation campaign of 2011 and 2012 indicates that cold pool outflows (CPOs) from convective downdrafts are the primary meteorological driver of these summertime emissions, followed by nocturnal low-level jet (LLJ) breakdown, both mesoscale phenomena which numerical models struggle to represent faithfully. Very few surface observations are available to characterise these emission mechanisms, however, and the extent to which Fennec observations are representative remains unclear. Satellite data from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) offers both the volume of data and resolution to observe emission mechanisms on the long term. In this thesis, two sets of automated algorithms are applied to 14 years of summertime SEVIRI data, the first of which categorises automatically identified and tracked dust by emission mechanism and the second of which tracks and characterises dust-laden cold pool outflows. CPOs account for 82% of the total observed dust and 88% at the point of emission in the central and western Sahara during boreal summer, which is the highest estimate yet of their contribution. Whereas CPO dust is widespread and the majority of dust source regions are primarily CPO-driven, LLJs dominate a small number of hotspots such as the Tidihelt Depression. CPOs are far-reaching, with 22.5% travelling over 300 km. They also follow a clear diurnal cycle which favours emissions in the late afternoon and evening. Unlike dust emission, CPO frequency peaks in August in southern Algeria. In the final component of the thesis, satellite observations are used to support a Met Office Unified Model experiment diagnosing the role of orography in driving dust-emitting LLJs over central Algeria. Fluvial drainage from mountains is thought to contribute erodible sediment to western Saharan dust sources, but their effect upon emission mechanisms there is untested. Removing the Hoggar mountains reduces LLJ emission frequency by approximately 30% as an elevated heating anomaly helps sustain the strong pressure gradient driving low-level winds across the region in summer. This thesis offers a meteorological perspective on satellite dust source maps, showing the contribution of erosivity to known summertime emission hotspots on climatic timescales. The fact that most central and western Saharan dust sources are predominantly activated by CPOs poses a challenge for numerical modelling of the dust cycle given the inadequate representation of downdrafts in models with convective parameterization.

Minimally invasive surgical procedures have become more favourable to their traditional surgical counterparts due to their reduced risks, faster recovery times and decreased trauma. Despite this, there are still some limitations involved with these procedures, such as the spatial confinement of operating through small incisions and the intrinsic lack of visual or tactile feedback. Specialised tools and imaging equipment are required to overcome these issues. Providing better feedback to surgeons is a key area of research to enhance the outcomes and safety profiles of minimally invasive procedures. This thesis is centred on the development of new microfabrication methods to create novel fibre optic imaging and sensing probes that could ultimately be used for improving the guidance of minimally invasive surgeries. Several themes emerged in this process. The first theme involved the use and optimisation of high-resolution 3D injection of polymers as sacrificial layers onto which parylene-C was deposited. One outcome from this theme was a series of miniaturised parylene-C based membranes to create fibre optic pressure sensors for physiological pressure measurements and for ultrasound reception. The pressure sensor sensitivity was found to vary from 0.02 to 0.14 radians/mmHg, as the thickness of parylene was decreased from 2 to 0.5 μm. The ultrasound receivers were characterised and exhibited a noise equivalent pressure (NEP) value of ~100 Pa (an order of magnitude improvement compared to similarly sized piezoelectric hydrophones). A second theme employed high-resolution 3D printing to create microstructures of polydimethylsiloxane (PDMS) and subsequently formed nanocomposites, to create microscale acoustic hologram structures. This theme included the development of innovative manufacturing processes such as printing directly onto optical fibres, micro moulding and precise deposition which enabled the creation of such devices. These microstructures were investigated for reducing the divergence of photoacoustically-generated ultrasound beams. Taken together, the developments in this thesis pave the way for 3D microfabricated polymer-based fibre optic sensors that could find broad clinical utility in minimally invasive procedures.

This thesis reports on experimental and numerical investigations of the onset of relativistic transparency in initially solid density plasmas, during interactions with an ultra-intense short laser pulse and the effect this has on the resulting plasma dynamics. The research presented was conducted with the aim of increasing understanding of the complex dynamics of these interactions to accelerate the development of particle and radiation sources towards potential applications. These range from being a driver for inertially confined fusion to proton therapy for cancer treatment. To this end, control of the interaction conditions and optimisation of the particle and radiation sources generated are essential. The thesis reports results which support and deepen understanding of plasma dynamics in the relativistic transparency regime. In the first of these experiments, the onset time of transparency in initially opaque plasmas was investigated as a function of target thickness, pulse energy and pulse duration for pulses with a maximum intensity on the order of 3 × 1020 Wcm−2 , on-target energies of ∼3 J and minimum pulse lengths of ∼50 fs. The fractional transmitted energy was found to match well with predictions using an established transparency model. Simultaneous frequency-resolved optical gating (FROG) measurements of the transmitted pulse profile compare favourably to particle-in-cell (PIC) code simulations. These simulations indicate that the coherent transition radiation generated by accelerated electrons interferes with the transmitted pulse in those targets which undergo transparency, resulting in fringes in the spectrum of the light measured at the target rear. This novel application of spectral interferometry is shown to be capable of high resolution measurements of the transmitted pulse spectrum and offers the potential ability to control and optimise the onset time of transparency in expanding thin foil targets. These results accelerate the development of ion acceleration in the transparency regime as the onset time greatly affects the ion beam properties, including maximum energy. In the second of these experiments, it was found that as target thickness is decreased from the micron scale to tens of nanometres that the absorption of laser energy to electrons transitions from surface to volume dominated processes. Experimental measurements of the energy absorption and the population of fast electrons escaping the target show a maximum of ∼ 80% total absorption at an optimum target thickness of ∼380 nm, with a slow decrease with increasing target thickness, for incident pulses with intensities on the order 9 × 1019 Wcm−2 and pulse lengths of ∼700 fs. For thinner targets, particle-in-cell code simulations indicate that transparency occurs increasingly early, which results in a decrease in absorption. However, the experimental results suggest that with decreasing thickness more electrons escape the target, with a higher average energy, with the particle-in-cell simulations predicting similar results. This increase in "escaped" electron fraction is attributed to a direct laser acceleration of the bulk target electrons. These findings indicate a trade-off between total energy coupling to the electrons and the spectral properties of the electron beam produced. In the third of these experiments, the role of transparency in laser driven ion acceleration is investigated. This mode consists of hybrid phases of RPA, TNSA and enhancement due to the onset of transparency, with recent experimental results suggesting this mechanism can accelerate protons to maximum energies on the order of 100 MeV, for pulses with intensities on the order 3 × 1020 Wcm−2 . By comparing results from aluminium and plastic targets, it is demonstrated that the chosen target material has an effect on the maximum energy and flux of the accelerated proton beam. Plastic targets are shown to produce higher energy protons, on laser-axis, compared to those from metallic targets due to the presence of hydrogen throughout the target volume rather than just in hydrocarbon surface contaminants. Particle-in-cell code simulations highlight the differing behaviour of the two target types investigated post-transparency where it is found that the peak accelerating field structures act to drive the proton population more efficiently in plastic targets. These results provide a key motivation for the choice of target material for a number of applications, where high energy, high flux proton beams are desired. The results of these investigations enable a greater understanding of the complex dynamics of initially solid density foil targets dynamically expanding to the point at which they become relativistically transparent to the intense laser light, accelerating the development of these novel ion sources towards potential applications.

This thesis presents an investigation into the nature and use of the consort organ in English secular instrumental music of the seventeenth century with a view to informing present-day performance practice. Whilst the English string consort repertoire has been widely studied from the perspective of the viol and violin, the role of the organ and organist has remained neglected. This study seeks to redress this through the examination of manuscript sources, contemporary writing and extant instruments to illuminate a variety of performance practice issues. The development and organology of the instrument is considered, focussing particularly on the distinctive methods of construction and voicing that were designed to enhance the instrument's role in playing with string ensembles. The contexts of chamber music at the court, in domestic establishments, and in theatres, choir schools and music meetings are examined from the perspective of the consort organ. Manuscript sources, contemporary historical sources and the consideration of extant instruments in relation to their original locations and associated repertoire are interrogated for performance practice information. The role of the consort organist, from both a musical and sociological standpoint, is also discussed with reference to contemporary sources. The findings reveal that seventeenth-century usage of the organ differed from present-day practice in relation to a number of key areas including pitch, temperament, registration and expression, and that the organist's role encompassed a wide range of skills that are rarely explored in modern performances or editorial realisations. The study concludes that a revised approach to the use of the consort organ in present-day performance of the seventeenth-century English consort repertoire is required.