This dissertation consists of three chapters discussing the effects of changing trade barriers for Canadian firms and a final chapter investigating hazardous waste trade, one of the important environmental issues in international business. The first three chapters use simple theoretical structures and firm level data to examine the evolution of Canadian manufacturing following the tariff changes imposed by the Canada-US Free Trade Agreement. Chapter one considers the influence of falling tariffs on firm survival, chapter two investigates how trade liberalization effects firm growth in terms of size and productivity, and the third chapter considers the implication o f falling trade barriers for firm financial structure. The fourth chapter diverges from the first three to explore the determinants of international shipments in hazardous waste using a gravity model with factor endowment conditions and waste trade data from 89 countries. / Business, Sauder School of / Graduate

D.Sc. / The ion exchange properties of a number of synthetic inorganic ion exchangers and the natural zeolite, clinoptilolite, were evaluated with respect to the elements Na, Cs, Sr, Ba, Ce(III), Eu, Zr, U(VI), Np(V), PU(IV) and Am(III). The role of the structure of crystalline exchangers in determining the selectivity thereof, especially in the case of clinoptilolite, was also investigated. Hydrated antimony pentoxide and antimonic acid showed high sorption of a number of ions over a wide pH range (2 - 10). The selectivity order of hydrous oxides for the actinides was as follows: PU(IV) > Am(III) > U(VI) > Np(V). Titanium phosphate, zirconium phosphosilicate and sodium titanate, however, preferred U to Am. To predict the selectivity order of crystalline inorganic ion exchangers, the Eisenman theory could be used, but other factors such as ion sieve effects had to be taken into account. In such cases the parameters contributing to the change in free energy during ion exchange plays a major role. Samples containing clinootilolite from two deposits in South Africa were evaluated with respect to chemical composition, conversion to the sodium, calcium and cesium forms, as well as the sorption of Cs and Sr from various media. Similar trends to those:reported for clinoptilolite from other parts of the world were found. Rietveld refinement of the structure of Cs-exchanged clinoptilolite was carried out using powder diffraction data and the computer program WYRIET. The zeolite was not isolated from the natural matrix, which meant that a number of phases had to be included in the refinement process. The refinement confirmed the...

Efficient treatment of waste materials from agricultural operations is a problem in most of the countries of the world. This is particularly true where livestock are being reared in large high-production confinement housing systems. There are several treatment systems available to handle the wastes from this type of operation. These systems are described with particular emphasis on thermophilic fermentation. Thermophilic treatment of wastes offers several advantages over the other types of waste treatment systems. The thermophilic system at the University of British Columbia differs from most other high-temperature systems in that no external heat source is provided. Experiments were carried out which show that the heat necessary to maintain the temperature in the thermophilic range comes solely from microbial activity. The actions of agitation and aeration do not provide any input of heat into the fermenter. The foam which forms on the top of the liquid during a fermentation was shown to be a good insulator. Feeding trials conducted with the liquid product from thermophilic fermentation demonstrated that this liquid can be substituted for water in the diet of pigs older than twenty-eight days of age with no harmful effects. It is possible that pigs older than fifty-six days of age will be able to utilize the nutrients in the liquid more efficiently and increase their rate of gain without increasing the amount of feed consumed. Experiments with larger sized fermenters resulted in a commercial design for a thermophilic waste treatment system with a total capacity of six thousand gallons. Finally, preliminary trials utilizing lignocellulose as a substrate for thermophilic bacteria indicated that these bateria are able to utilize cellulose as a nutrient source. / Land and Food Systems, Faculty of / Graduate

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The annual national production of peanut hulls averages about two hundred million pounds. These hulls are generally disposed of as fuel in the plante processing the nuts or discarded as waste material. Similar cellulosic wastes have been profitably utilized in the past as activated ohars. It was the purpose of this work to determine the conditions by which peanut hulls could be converted to liquid adsorbent chars. / Master of Science

Evaluation of the data from the series of batch experiments has led to the following conclusions: 1. Currently used methods of quantifying oxygen uptake rate, especially for batch reactors, yield values of oxygen utilization considerably lower than those predicted by mass balance considerations for these three wastes. In the face of Blok's published data indicating much better results with a short run reactor, it must be assumed that the length of run selected was at least partially responsible. 2. While quantitatively unsatisfactory, the methods for determining oxygen uptake used in these experiments seem to be of some use as monitors of biological systems. Changes in slope of the oxygen utilization curve were found to be more apparent at lower loadings. / Master of Science

Nine recirculating systems at the Virginia Tech Aquaculture Center were placed on line and stocked with yellow perch, <I>Perca flavescens</I>, fingerlings. Fish were stocked at a density of approximately 455 fish m³. Biofilter types were the only factor differing among system designs and were an upflow pulsed bed bead filter, packed tower trickling filter and a rotating biological contactor (RBC). After stocking, systems were allowed to acclimate using ammonia excreted by the yellow perch. Following acclimation, a comparative analysis on biofilter performance began. To evaluate filter performance, water quality parameters tested were temperature (°C), pH, dissolved oxygen (DO), total ammonia-nitrogen (TAN), nitrite-nitrogen (NO₂⁻-N), nitrate-nitrogen (NO₃⁻-N), alkalinity (as CaCO₃), water hardness (as CaCO₃), carbonaceous biochemical oxygen demand (cBOD₃), dissolved organic carbon (DOC), and total suspended solids (TSS). Basic water quality analysis encompassed samples drawn at 8 AM. TAN mass removal analysis encompassed water quality samples drawn at 8 AM and over 24 hours. Higher TAN mass removal rates were achieved in trickling and RBC filters than in bead filters for 8 AM (0.037, 0.14, and 0.004 g/m²/d, respectively) and diurnal sample periods. Analysis of areas under mass removal curves depicted RBC filters as surface area limited. Trickling filters proved most effective at carbon dioxide stripping and pH maintenance and also effectively removed TSS from the culture water. The study did not show filter type as having a significant effect on median organic water quality parameter values. / Master of Science