Thesis--M. Sc.(Eng.), University of Hong Kong. / Mimeographed.

This report outlines the creation of my thesis project “The Revolutionaries: An Untold History of Freedom” from concept to completed film. The Revolutionary Movement was an underground militant movement in pre-independent India which sought to overthrow the British government by force. The film interleaves the interview of an elderly ex-Revolutionary with a high-level history of this mostly-forgotten underground movement. / text

published_or_final_version / Electrical Engineering / Doctoral / Doctor of Philosophy

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During several decades considerable research activities have been conducted with respect to fires in coal mines, but the research activities with respect to hard rock mines have been limited. As the hard rock mines are getting more complex the need for deeper understanding of fires in underground hard rock mines are getting more in demand. The more urgent demands are the need for more specific heat release rate curves as design fires, applicable fire experiments and any method that would allow for the calculation of the total heat release rate curve of an object. This thesis presents a number of examples on design fire curves applicable to underground hard rock mines; it also presents the results of model scale fire experiments and methods for calculating the total heat release rate of several objects at uniform as well as non-uniform conditions. Tests were carried out in a model scale tunnel using wooden pallets as fire load. The parameters tested were the distance between piles of pallets and longitudinal ventilation rate. It was found that an increasing ventilation rate also increases the peak heat release rate. When studying the curves of heat release rates it was found that when the distance between the ignited pile and the second pile increased to a certain level the delayed ignition of the second pile will result in that the peak heat release rate of the adjacent piles will not occur simultaneously. The ignition data indicated that the ignition time of adjacent piles decreased as the longitudinal ventilation increased.  A method using a critical heat flux as ignition criterion exhibited very good agreement with the corresponding experiments for both uniform as well as non-uniform conditions. The methods using the ignition temperature as ignition criterion did not agree very well with any of the corresponding experiments. / GRUVAN

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Research shows miners can be exposed to foot-transmitted vibration (FTV) when operating various pieces of underground mining equipment, and case reports suggest workers are experiencing symptoms similar to those of hand-arm vibration syndrome in their feet. A field study was conducted to measure and document FTV exposure associated with operating underground mining equipment, and probable health risks were determined based on both ISO 2631-1 (1997) for WBV and ISO 5349-1 (2004) for HAV. Seventeen participating operator’s also reported musculoskeletal discomfort. Seventeen male participants ranging between 24-61 years of age, with an average height and mass of 175.0cm and 88.2kg volunteered for the study. Seventeen pieces of equipment were tested; 1 locomotive, 1 crusher, 9 bolter drills (4 scissor platforms, 2 Maclean, 2 Boart/basket, and 1 RDH), and 6 jumbo drills. Including all seventeen pieces of underground mining equipment, the vibration acceleration ranged from 0.13-1.35m/s2 with dominant frequencies between 1.25-250Hz according to ISO 2631-1. According to ISO 5349-1 vibration acceleration ranged from 0.14-3.61m/s2 with dominant frequencies between 6.3-250Hz. Furthermore, the magnitude of FTV measured on the jumbo drills with grated platforms (#5 and #6) was less than FTV measured from the jumbo drills with, solid metal surfaces. Additionally, twelve of the seventeen equipment operators indicated a complaint of discomfort in their lower body (specifically at the level of the knee or lower). The health risk analysis based on ISO 2631-1 indicated that one operator (bolter drill #9) was exposed to vibration above the criterion value, while the health risk analysis based on ISO 5349-1 indicated iv that two operators (jumbo drill #1 and bolter drill #1) were exposed to vibration above the criterion value. Operators reported very severe or severe discomfort; however, the same operators were not the operators of the equipment with FTV exposure levels above the ISO standards, leaving evidence to suggest that the standards are not properly assessing injury risk to vibration exposure via the feet. Future research is needed to develop a standard specific for FTV and to determine the link between early musculoskeletal injury reporting and the onset of vibration white foot. To do so, a better understanding of the biodynamic response of the foot to FTV is needed. A laboratory study was conducted to 1) measure and document transmissibility of FTV from (a) floor-to-ankle (lateral malleolus), and (b) floor-to-metatarsal, during exposure to six levels of vibration (25Hz, 30Hz, 35Hz, 40Hz, 45Hz, and 50Hz) while standing, and 2) to determine whether independent variables (vibration exposure frequency, mass, arch type) influence transmissibility (dependent variable) through the foot. A two-way repeated measures analysis of variance (ANOVA) was conducted. There was a significant interaction between transmissibility location and exposure frequency (λ = 0.246, F (5,25) = 15.365, p = 0.0001). There were significant differences in mean transmissibility between the ankle and metatarsal at 40Hz [t(29) = 4.116, p = 0.00029], 45Hz [t(29) = 6.599, p = 0.00000031], and 50Hz [t(29) = 8.828, p = 0.000000001]. The greatest transmissibility at the metatarsal occurred at 50Hz and at the ankle (lateral malleolus) transmissibility was highest from 25-30Hz, indicating the formation of a local resonance at each location. v Future research should focus on identifying resonance frequencies at different locations on the feet. This information is needed to develop an exposure guideline to help protect workers from exposure to FTV, and to develop personal protective equipment capable of attenuating harmful FTV exposure frequencies.

Long-term mine plans are based on forecast future metal prices. By the time the development is put in place, the forecasts may have been proved wrong and the production plan might not meet the company's financial objectives. At that point, the common reaction to this situation is to create a new revised long-term plan and spend more capital, only to find out at a later time that the metal prices have changed again. This results in an inefficient use of capital with low returns to the investors. The objective of this thesis is to develop a methodology to determine the cut-off grade and production rate of a narrow-vein underground mine such that the long-term strategic plan is robust. As a requirement to do so, it is necessary to have a good understanding of the resources, revenues, capital and operating costs as a function of the design parameters. Also, the operational limits of the mine must be determined so that the solution is practical. Afterwards, annual metal prices are randomly generated with a Monte Carlo process on stochastic metal price models, and the combination of production rate and cut-off grade yielding the highest net present value is identified and recorded. This process is repeated many times, and the probabilities of the solutions occurring at any given design combination are calculated. The results are plotted on a bubble graph, where the size of a bubble is directly proportional to the probability a solution occurs at that point. Finally, the combination with the largest bubble is the solution, as this point has the highest probability of yielding the highest net present value in most circumstances. The model was first tested on an actual gold-copper orebody where very detailed resource and cost information was available. The methodology was applied with success and the solution reflected the important impact of the copper milling and roasting process on revenues. Other tests were then done on a hypothetical gold orebody and the results showed a great degree of sensitivity to the average grade of the deposit. / Thesis (Ph.D, Mining Engineering) -- Queen's University, 2008-04-25 12:42:24.623

In this thesis, a new method has been proposed for calculating the frequencydependent parameters of underground cables. The method uses full wave formulation for calculating the modal electromagnetic fields and corresponding voltages and currents and then extracting frequency-dependent per unit length parameters of underground cables. The proposed method can be used for any cross-sectional shape of cables.