Introduction: Diesel fuel (D) is used in a variety of applications for several industries, including transportation, agriculture, railroads, construction, and mining. In addition to being non-renewable, combustion of diesel fuel (D) leads to negative occupational health outcomes in mining. Currently the Mine Safety and Health Administration (MSHA) regulates diesel exhaust exposure with an 8-hour, time-weighted average permissible exposure limit (PEL) of 160 µg/m3 respirable (<1.0 µm in size) diesel particulate matter (rDPM). Alternative fuels such as biodiesel (B) and a natural gas/diesel blend (GDiesel® [G]) are considered promising alternatives. While the former fuel has been extensively investigated, the latter has not. Objectives: The aims of this dissertation were: (1) to evaluate and compare D and G exhaust exposures from operation of a Wagner and a (2) JCI load-haul-dump (LHD) at the University of Arizona San Xavier Underground Mining Laboratory (SX); and (3) to synthesize existing peer-reviewed literature comparing D emission exposures to those of B and/or G. Methods: For Aims 1 and 2, operator-location and area exposure samples were collected for 200 minutes in an underground mining laboratory while an LHD with oxidation catalyst was operated with D and then G fuel. Analytes of interest included total diesel particulate matter (tDPM) and rDPM, total and respirable elemental and organic carbon (tEC, rEC, tOC, rOC, respectively), as well as the carbonyl compound (CC) formaldehyde (CH2O), nitric oxide (NO), and nitrogen dioxide (NO2). Exposure assessment was conducted within the guidelines of the National Institute of Occupational Safety and Health’s (NIOSH) Manual of Analytical Methods. Specifically, methods #5040 (tDPM, tEC, tOC, rDPM, rEC, rOC), #6014 (NO, NO2), and #2016 (CH2O). Reported laboratory results were time-weighted over an 8-hour period. Between-fuel comparisons were performed using Wilcoxon rank sum testing. Results: For Aim 1, twenty-three D and 12 G samples were collected. Use of G in the Wagner LHD showed statistically and practically significant reductions in rDPM, tDPM, elemental and organic carbons, NO, NO2, and CH2O. For Aim 2, twenty D and 16 G samples were collected. Use of G in the JCI LHD was associated with a significant decrease in NO2 (p=0.012), and significant increase in rEC (p=0.024). After removing outliers, tEC also showed significant increase (p=0.023). Most of the 20 scholarly works reviewed utilized a laboratory setting (75%), while just 15% were conducted in the field, and 10% simulated field conditions. Twenty percent (4) of studies specifically focused on the mining industry. In addition, most evaluated soy-based B (56%) but did not utilize pollution controls (70%) on equipment. Generally, literature showed that use of B decreased DPM and increased oxides of nitrogen (NOx) emission exposures. While more studies (5) showed increases in CCs, two showed decreases. Discussion: Our studies show that: 1) the use of G has potential for statistically and practically significant reductions in several D exhaust contaminants regulated by MSHA; and 2) variability in exposure and emission concentrations across engine, pollution control and operation configurations exists for B and likely exists for G. Differences observed across fuels and studies are also likely due to fuel composition and characteristics, and combustion temperatures. Further occupational health research is needed to evaluate G emissions under controlled conditions with various equipment configurations, as well as in-field settings to determine whether G exhaust exposures are reduced and actually less toxic than those of D. The impact of this work is substantial and timely. Recent increases in respiratory disease prevalence among miners, including young miners, concerns occupational health and industrial hygiene professionals. In addition, MSHA has requested information regarding diesel exhaust controls and is considering future revisions to the rDPM standard. Efforts to reduce D exhaust emissions will also impact occupational and environmental health worldwide.

This thesis describes numerical methods for the evaluation of the series impedance matrix and shunt admittance matrix of underground cable systems. In the series impedance matrix, the terms most difficult to compute are the internal impedances of tubular conductors and the earth return impedance. The various formulae for the internal impedance of tubular conductors and for the earth return impedance are, therefore, investigated in detail. Also, a more accurate way of evaluating the elements of the admittance matrix with frequency dependence of the complex permittivity is proposed. Various formulae have been developed for the earth return impedance of buried cables. Using the Pollaczek's formulae as the standard for comparison, the formula of Ametani and approximations proposed by other authors are studied. Mutual impedance between an underground cable and an overhead conductor is studied as well. The internal impedance of a laminated tubular conductor is different from that of a homogeneous tubular conductor. Equations have been derived to evaluate the internal impedances of such laminated tubular conductors. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

This thesis presents a new model to simulate the behaviour of underground cable systems under transient conditions. The new cable model belongs to the class of time-domain, frequency-dependent models, and it is directly compatible with the solution algorithm of the EMTP (Electromagnetic Transients Program). The most important feature of the new model is that it takes into account the frequency dependence of the modal transformation matrices and cable parameters, thus overcoming the main limitation of currently-used transmission line and cable models, which assume that the modal transformation matrices are constant Conceptually, the new model is relatively simple. The system parameters which define the behaviour of an underground cable (namely the modal characteristic admittance matrix, the modal propagation matrix, and the modal transformation matrix), are expressed in closed form by approximating them with rational functions in the frequency domain. Therefore, in the time domain, all numerical convolutions can be expressed recursively. The host transients program (to which the model is interfaced) sees the new model as a constant, real admittance matrix, in parallel with a continuously-updated vector current source. The accurate approximation by rational functions of the modal transformation matrix is possible when its elements are continuous and smooth functions of frequency. Standard eigenvalue/eigenvector algorithms are not well suited for this purpose. Therefore, a new procedure to generate eigenvalues and eigenvectors has been developed. This procedure is based on the Jacobi method, and it produces the desired smooth functions of frequency. This manuscript presents a number of simulations where the performance of the new cable model is compared with exact analytical solutions. These simulations show an excellent agreement between analytical and numerical answers. The effects of not taking into account the frequency dependence of the modal transformation matrices is illustrated with the simulation of a line-to-ground fault on a three-phase cable. The response of the new cable model is also compared with results measured in a field test The new cable model is numerically stable. Its computational speed is comparable to that of frequency-dependent line models with constant transformation matrices. The new cable model is general. Its extension to the simulation of multiple-circuit overhead transmission lines should also be of considerable practical importance. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

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Modeling the Cosmic Muon Flux is very important for quantifying the backgrounds present for underground experiments. We measure the flux at various locations in the Kimballton Underground Research Facility (KURF) and compare these measurements with our model. / Ph. D.

Shek Wai Ling, Sophy. / "Architecture Department, Chinese University of Hong Kong, Master of Architecture Programme 2010-2011, design report." / Chapter 00 --- Thesis Statement / Chapter 01 --- Background Study / Chapter 02 --- Site Analysis / Chapter 03 --- Underground Space / Chapter 04 --- Design Strategy & Development

Thesis (Ph.D.)--University of Tulsa, 1991. / Bibliography: leaves 228-233.

Thesis (Ph.D.)--University of Tulsa, 1991. / Bibliography: leaves 228-233.

M.S.