One of the most important issues in suspension polymerisation process is the control of the final particle size distribution (PSD) as this is an indicator for both quality and financial matters. For polymer manufacturers, a narrow PSD is always welcome. The conventional reactors, e. g. stirred tank reactors, generally produce particles of a rather broad PSD. As a result, to explore a new type of polymerisation devices becomes a challenging task. The objectives of this PhD study are to apply a novel mixing apparatus, the oscillatory baffled reactor (OBR), to batch polymerisation of MMA and Styrene (crosslinked) and to characterise all the major aspects of the OBR involved in the pioneering work, with a view to assessing its potential for industrial applications. In order to carry out such investigations, a 1.2 litre batch jacketed OBR system with temperature control and on-line data acquisition units was designed and built. In addition, an off-line image capture system was set up f or droplet studies. From heat transfer study in the OBR, it was found that the temperature profiles across and along the reactor were uniform and a heat transfer correlation was obtained. The oil-water dispersion in the OBR was then investigated for various baffle designs, dispersed phase fractions and the levels of surfactants, enabling the optimal baffle type and parameters to be identified. In order to understand the droplet behaviour in the OBR, the droplet size distribution (DSD) was examined on dispersion uniformity, oscillation time, operational conditions, baffle thickness and the level of surfactant addition. It was found that the DSDs were very uniform within the reactor and the oscillation frequency and amplitude had the same effect on controlling the DSDs. Finally, a series of PMMA and PS tests were successfully conducted in the OBR, indicating that the polymer PSD can be controlled by adjusting both oscillation conditions and the baffle orifice diameter and that the OBR has the potential to produce uniform polymer particles at high oscillation frequencies. A correlation between droplet sizes with no reaction and final polymer particle sizes was established, which can be used to predict the final polymer sizes.

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A windows based computer program to compute fish back-calculated lengths at age was created using Visual Basic 6.0© programming language. The objective of this project was to develop a computer program that is user-friendly and requires minimal user input to produce back-calculations. This program incorporates the familiar windows based graphical user interface and can compute up to 10,000 fish with a maximum age of 50 years. The input data can be imported from an Excel spreadsheet or manually entered directly to the program. Back-calculated lengths were computed using the traditional Lee method [ (L; = a + [ (L, - a) ( S; / Sc ) ]. Additional related statistical outputs are also included. The output data can be viewed using Excel where it can also be formatted for individual use. The program was compared with DisBcal using yellow perch age and length data. Results of the comparison were nearly identical with differences due to a rounding function of the output data. / Department of Biology

Thesis (Ph. D.)--University of New South Wales, 1997. / Also available online.

Thesis (Honors)--Liberty University Honors Program, 2007. / Includes bibliographical references. Also available through Liberty University's Digital Commons.