Mackay Theses and Dissertations Grant Collection

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    Computer simulation and control of the mine locomotive system
    (University of Nevada, Reno, 1991) Widzyk, Eleonora; Taylor, Danny; Daemen, Jaak; Trzynadlowski, Andrzej
    The existing technology in the fields of monitoring instrumentation and remote control equips the mining industry with a powerful tool for optimization of underground haulage systems. Transport automation and computerization increases the system's dependability and safety factor and decreases the transport expenditure. Simulation of a computer controlled mine locomotive system was performed to determine the status of the train in the system. The input/output variables were: detection of the train location, direction of movement, weight measurement of a mine car at a designated station, and light signals indicating the necessary road clearance for locomotive transport. A computer program was developed to provide for monitoring and control of the status of the train. Draw-bar pull test was performed for the locomotive as part of the locomotive resistance characteristic determining the coefficient of adhesion between wheels and steel rails.
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    Geology and geochemistry of the Almanor and Glidden barite deposits, northern California
    (University of Nevada, Reno, 1984) Wigglesworth, John Bradley; Hsu, Liang-Chi; Larson, L. T.; Smith, Ross W.
    The Almanor and Glidden bedded barite deposits are at the northern end of a 700 km long "California barite belt", and are associated with siliceous sediments and volcanic arc derived rocks of Devonian (?) and middle Devonian age respectively. Regional geologic relations allow correlation of these deposits with similar deposits of north central Nevada. Geochemical evidence suggests a hydrothermal source for the barium. Cyclic stratigraphic variations in the strontium content of barite from the Glidden deposit may be the result of cyclic temporal variations in the physico-chemical environment of mineralization.
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    Geochemical and isotopic evidence for hydrologic processes at Owens Lake, California
    (University of Nevada, Reno, 1995) Font, Karen R.; Tyler, Scott W.
    Dust mitigation at Owens Dry Lake requires an understanding of the hydrologic system because one proposed remedial strategy is flooding dust-producing areas with groundwater pumped from deep aquifers. This study uses geochemical evidence to define hydrologic processes. Solutes in shallow groundwater (< IO m) are controlled by evaporation, mineral dissolution, convective mixing, changes in salt morphology, diffusion, and partial lake desiccation. Deep groundwater in east and west portions of the basin is relatively old (>20.000 14 C yr) compared to groundwater recharged from the north (-7. 760 14C yr). Modern (< I 00 14 C yr) recharge discharges in margin springs. Groundwater from different depths mixes in a fault zone in the northeast portion of the lake bed. Geochemical evidence of downward groundwater flow contradicts current conditions of upward hydraulic gradients. Groundwater flow out of the basin required at least 12 m of surface water.
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    Faulting and tectonics in the foreland basin fold/thrust belt of the San Juan Province, Argentina, and a comparison to the Yakima fold/thrust belt of the northwestern United States
    (University of Nevada, Reno, 1991) Whitney, Robert A; Lintz, J., Jr.
    The San Juan Province of west-central Argentina lies in a region of crustal shortening, the result of subhorizontal subduction in the Peru-Chile trench to the west. This crustal shortening is manifest as a north-south trending fold/thrust belt affecting the western edge of the South American craton and the adjacent continental slope. Shortening is accomplished on flattening thrusts, with decollement at moderate depths, controlled by bedrock lithology. Seismicity occurs in the subducted slab as Benioff zone seismicity and in the upper portions of the continental crust. A major strike-slip fault separates the foreland basin/craton shortening from the Andes uplift. The crustal shortening episode began about 9 Ma, but Quaternary activity is limited to the western edge of the craton and the eastern edge of the Paleozoic continental shelf. Historically, large earthquakes in the fold/thrust belt have not produced primary surface rupture, but secondary rupture on bending moment faults has occurred, both normal and reverse in mechanism. This phenomena indicates small secondary displacements can be indicative of very large events. The pattern of bending moment fault hypocenters complicates efforts to determine the geometry of the causative fault and to choose the correct focal plane solution. The Yakima fold/thrust belt of the northwestern U.S. is an area undergoing north-south crustal shortening similar to that in South America, although less active by about an order of magnitude. Comparison between the two regions indicates fault geometry and structure resulting from the crustal shortening are similar. Seismic risk analyses in the Columbia Plateau region have underestimated earthquake hazard by using incorrect models for the faulting and failing to consider the possibility of large magnitude events that do not have primary surface rupture.
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    Distribution and standard target clean-up levels of polycyclic aromatic hydrocarbons at Massachusetts Military Reservation, Cape Cod, Massachusetts
    (University of Nevada, Reno, 1995) White, Wesley; Daemen, Jaak; Watters, Robert; Carr, James R.
    During prior Site Investigations and Remedial Investigations on individual sites at the Massachusetts Military Reservation (MMR), Polycyclic Aromatic Hydrocarbon (PAH) contamination has previously been associated with past improper waste disposal activities. However, recent studies on PAHs have shown anthropogenic background levels in urban environments above the acceptable levels for CERCLA, MADEP, and risk/hazard equivalent concentrations. Each site with PAH data is statistically examined at three groups: Surface Risk Soil Samples (0-2 ft depth); Occupational Risk Soil Samples (0-12 ft depth); And, All Soil Data for each site. The three categories roughly show PAH risk receptor levels, PAH depositional history, and any possible migration of PAH contamination. A comparison to CERCLA, MADEP, and risk/hazard equivalent concentrations to the maximum observed PAH contamination reveals which sites may need remedial action. On the other hand, a closer look at the maximum contamination to PAH depositional processes suggest urban anthropogenic processes are related to the PAH contamination on several sites at the MMR. A general look at the spatial distribution of PAHs to major roads, taxiways, and runways reveals a linear trend which suggest significant levels of nonpoint source anthropogenic PAH background contamination. Based on the findings of this thesis, the recommendation for PAH soil target clean-up levels at MMR should be based on published urban PAH levels which take into account nonpoint source anthropogenic contamination.