Three Essays on Economic Development in the Natural Resources Sector

This thesis examines two ongoing development projects that received financial support from international development organizations, and an alternative mining tax proposed by the academia. Chapter 2 explores the impact of commoditization of coffee on its export price in Ethiopia. The first part of the chapter traces how the Ethiopian’s current coffee trade system and commoditization come to be. Using regression analysis, the second part tests and confirms the hypothesis that commoditization has led to a reduction in coffee export price. Chapter 3 conducts a cost-benefit analysis on a controversial, liquefied natural gas export project in Peru that sought to export one-third of the country’s proven natural gas reserves. While the country can receive royalty and corporate income tax in the short and medium term, these benefits are dwarfed by the future costs of paying for alternative energy after gas depletion. The conclusion is robust for a variety of future energy-price and energy-demand scenarios. Chapter 4 quantifies through simulation the economic distortions of two common mining taxes, the royalty and ad-valorem tax, vis-à-vis the resource rent tax. The latter is put forward as a better mining tax instrument on account of its non-distortionary nature. The rent tax, however, necessitates additional administrative burdens and induces tax-avoidance behavior, both leading to a net loss of tax revenue. By quantifying the distortions of royalty and the ad-valorem tax, one can establish the maximum loss that can be incurred by the rent tax. Simulation results indicate that the distortion of the ad-valorem tax is quite modest. If implemented, the rent tax is likely to result in a greater loss. While the subject matters may appear diverse, they are united by one theme. These initiatives were endorsed and supported by authorities and development agencies in the aim of furthering economic development and efficiency, but they are unlikely to fulfill the goal. Lessons for international development can be learnt from successful stories as well as from unsuccessful ones.

Refractometry Studies of the Optical Properties of Polymer Films and the Development of Polymer Coated Refractive Index Sensors

Sensors for real-time monitoring of environmental contaminants are essential for protecting ecosystems and human health. Refractive index sensing is a non-selective technique that can be used to measure almost any analyte. Miniaturized refractive index sensors, such as silicon-on-insulator (SOI) microring resonators are one possible platform, but require coatings selective to the analytes of interest. A homemade prism refractometer is reported and used to characterize the interactions between polymer films and liquid or vapour-phase analytes. A camera was used to capture both Fresnel reflection and total internal reflection within the prism. For thin-films (d = 10 μm - 100 μm), interference fringes were also observed. Fourier analysis of the interferogram allowed for simultaneous extraction of the average refractive index and film thickness with accuracies of ∆n = 1-7 ×10-4 and ∆d < 3-5%. The refractive indices of 29 common organic solvents as well as aqueous solutions of sodium chloride, sucrose, ethylene glycol, glycerol, and dimethylsulfoxide were measured at λ = 1550 nm. These measurements will be useful for future calibrations of near-infrared refractive index sensors. A mathematical model is presented, where the concentration of analyte adsorbed in a film can be calculated from the refractive index and thickness changes during uptake. This model can be used with Fickian diffusion models to measure the diffusion coefficients through the bulk film and at the film-substrate interface. The diffusion of water and other organic solvents into SU-8 epoxy was explored using refractometry and the diffusion coefficient of water into SU-8 is presented. Exposure of soft baked SU-8 films to acetone, acetonitrile and methanol resulted in rapid delamination. The diffusion of volatile organic compound (VOC) vapours into polydimethylsiloxane and polydimethyl-co-polydiphenylsiloxane polymers was also studied using refractometry. Diffusion and partition coefficients are reported for several analytes. As a model system, polydimethyl-co-diphenylsiloxane films were coated onto SOI microring resonators. After the development of data acquisition software, coated devices were exposed to VOCs and the refractive index response was assessed. More studies with other polymers are required to test the viability of this platform for environmental sensing applications.