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This work describes the design, development and testing of a portable charge-coupled device detector system to be used for the simultaneous collection of X-ray diffraction and X-ray fluorescence data from powdered samples. The detector was designed for both terrestrial and extra-terrestrial applications that require in-situ analysis of samples, where access to a laboratory instrument is restricted. The detector system incorporates 4 e2v technologies CCD30-11 devices, employing multi-phase pinned technology for low noise operation. Geometrical calculations and thermal studies concerning the design of the detector are presented, with particular emphasis on motivations for the chosen geometry. Initial characterisation and calibration of the detector was performed in a laboratory environment using a purpose built test facility. The test facility included a high brightness X-ray micro-source from Bede Scientific Instruments, coupled with an XOS polycapillary collimating optic, which was used to deliver a focused beam of low divergent X-rays to the sample. The design of the test facility is discussed and the spectra and flux produced by the X-ray micro-source are investigated. The operational performance of the detector is highlighted and the use of the instrument in different applications is described, namely the planetary sciences and pharmaceuticals sector. Finally, based on the knowledge gained from initial testing of the instrument, improvements to the detector design are outlined, which greatly enhance the combined X-ray diffraction/X-ray fluorescence performance of the instrument.

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Thesis advisor: Thomas N. Seyfried / GM1 gangliosidosis is a glycosphingolipid lysosomal storage disease caused by a genetic deficiency of acid b-galactosidase (β-gal), the enzyme that catabolyzes GM1 within lysosomes. Accumulation of GM1 and its asialo form (GA1) occurs primarily in the brain, leading to progressive neurodegeneration and brain dysfunction. Less information is available on the neurochemical pathology in optic nerve and sciatic nerve of GM1- gangliosidosis. Here we analyzed the lipid content and myelin structure in optic and sciatic nerve in 7 and 10 month old normal β-gal (+/?) and GM1-gangliosidosis β-gal (-/-) mice. Optic nerve weight was lower in the β-gal -/- mice than in unaffected β-gal +/? mice, but no difference was seen between the normal and the β-gal -/- mice for sciatic nerve weight. The concentrations of GM1 and GA1 were significantly higher in optic nerve and sciatic nerve in the β-gal -/- mice than in β-gal +/? mice. The content and composition of myelin-enriched cerebrosides, sulfatides, plasmalogen ethanolamines were significantly lower in optic nerve of β-gal -/- mice than in β-gal +/? mice, however cholesteryl esters were enriched in the β-gal -/- mice. No significant abnormalities in these myelin enriched lipids were detected in sciatic nerve of the β-gal -/- mice. The abnormalities in GM1 and myelin lipids in optic nerve of β-gal -/- mice were also associated with abnormalities in the X-ray diffraction pattern including myelin content in fresh nerves [M/(M +B)] and periodicity (d). With the exception of a slight reduction in myelin content, no abnormalities in the X-ray diffraction pattern were observed in sciatic nerve of β-gal -/- mice. The results indicate that neurochemical pathology is greater in optic nerve than in sciatic nerve of β-gal -/- mice. / Thesis (MS) — Boston College, 2014. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology.

<p>Fiber-optic networks are an integral part of todays digital communication system. In these networks, distances of typically 400 km to 6000 km are linked together, and information is transfered at extremely high data rates. As the demands for capacity increases, finding new methods for cost effective long-haul transmission systems that can be used to increase the capacity becomes of high interest. In this work Orthogonal Frequency Division Multiplexing (OFDM), which is a standard digital modulation format in many wireless communication systems, for instance the IEEE 802.11n, is adapted to the optical domain and used for data transmission. The advantage of OFDM in the optical domain is that it transforms a high data rate stream into many simultaneously low bit rate streams that are efficiently frequency multiplexed. By doing so high spectral efficiency is achieved and many of the impairments encountered in high data rate transmissions are avoided. The disadvantage is however, that OFDM has inherently a high peak-to-average power ratio. As a result, OFDM suffers from nonlinearities occurring along the transmission line. The low nonlinear tolerance of OFDM in fiber optic applications restricts the feasible transmission distance. The goal of this work is to assess the suitability of OFDM in fiber-optic communications</p>