Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 102-107). Also available in electronic version. Access restricted to campus users.

Includes bibliographical references (p. 105-117).

published_or_final_version / Law / Master / Master of Philosophy

Biomonitoring has become an important component in bioassessment programs. It is used to maintain high water quality standards, and determine contaminant levels and biological affects in areas that have been heavily disturbed. The objectives of this research were 1) to improve and apply certain modern biomonitoring techniques and 2) to locate possible contaminant sources affecting the flora and fauna of the Green River and of Mammoth Cave. Actinonaias ligamentina (Lamarck, 1819), a freshwater mussel, was used for interpretation of these impacts as well as refinement of biomonitoring techniques. The mussels were collected in the Lawler Bend region of the Green River, an area upstream from the Mammoth Cave System, and from Haynes Shell Midden (dating 4000 - 6000 years before present) 45 miles downstream. Analyzing the shell nacre of these mussels, and the soft tissue of recently collected specimens, produced an abundance of information including high tissue concentrations of organochloride pesticides, significant concentrations of several metals including Cadmium, Copper, Mercury, Nickel, Silver and Zinc (with Mercury and Silver being found at the impact site), and numerous shell nacre stains. These results indicated possible impact from agriculture in the region and past and present contamination from local industries, and demonstrated the importance of the nacreous shell to biomonitoring programs.

As the recent environmental legislation highlights the risks associated with the use of gasoline additives such as octane enhancers, hydroisomerisation of n-alkanes in the gasoline feed to their corresponding isomers emerges as a key industrial alternative. Important catalysts have previously been tested and abandoned due to a number of problems including cost and poor resistance to catalyst poisons even in trace quantities. The current research evaluated the potentials of zirconia supported molybdenum carbide catalysts as replacements. The active carbided MoO3/ZrO2, MoO3/SO42- -ZrO2 and Rh/MoO3/ZrO2 have been prepared by in situ carburisation with CH4/H2 at 650oC and characterised by N2 adsorption, X-ray diffraction, X-ray photoelectron spectroscopy, Diffuse Reflectance Fourier Transformed Infrared spectroscopy, and temperature programmed reduction and oxidation. The characterisation data showed the carburisation process to proceed in a stepwise manner, involving the participation of hydrogen and methane as reducing and carbiding agents, respectively. Low (0.5 wt %) Rh loading and pre-treatment cycle via reduction and reoxidation significantly reduced the carburisation temperature, with the extent of the effect been dependent on the MoO3 loading. All of the catalysts produced showed stable activity and selectivity. Over the carbided MoO3/ZrO2, the activity was generally low at 450oC, producing mainly hydrogenolysis products. However, the activity of carbided MoO3/SO42- -ZrO2 at 350-450oC showed strong dependence on the nature of the n-alkane with reaction rates being lower for the higher alkanes. n-Nonane and n-octane produced mainly hydrocracking products whereas n-hexane and n-heptane were converted to the corresponding isomers with a very high selectivity. The catalyst forms a potential material for hydroisomerisation of gasoline range light paraffins. The 10 wt% Rh/MoO3/ZrO2 catalyst was more active to hydrogenolysis than with 25 wt% Rh/MoO3/ZrO2 under similar conditions due to higher activity of Rh species. However, the hydroisomerisation selectivity was highly favoured at lower temperatures, especially with n-hexane.

published_or_final_version / Public Administration / Master / Master of Public Administration

published_or_final_version / abstract / Computer Science / Master / Master of Philosophy

The two centuries from 1818 to 2004 cover profound social and economic changes in what was, for much of the period, the most powerful country in the world. Britain led the way in moving capital and labour out of agriculture and into newer industries, such as coal-mining, textiles and transportation. The changes were accompanied by deep institutional changes, especially in the franchise. The rate of change is remarkable: within seventy years Britain was almost completely democratic, in contrast to the 'rotten boroughs' and virtual feudalism of the pre- 1832 unreformed Parliaments. The changes are mirrored in the role given to agriculture within society, and in particular the amount and type of economic rent transferred from the consumer and the taxpayer to the farmer. This thesis uses two centuries of data and 'survival analysis' statistical techniques to show that Olson's celebrated theory of collective action can be substantiated in a dynamic context. I show that as the share of farmers in the workforce diminishes, and their relative wealth shrinks, the probability of the Cabinet increasing protection grows. The reverse is also the case, showing that the Cabinet responds positively to pressures from a group whose utility was diminishing.

No description available.

No description available.