Thesis (Ph. D.)--University of Hawaii at Manoa, 2001. / Includes bibliographical references (leaves 196-213). Also available on microfiche.

The first objective of this study is to measure, describe, and attempt to predict variations of net snow accumulation with elevation over a mesoscale area of 14 km² on a west coast midlatitude mountain. The second objective is to measure and describe similar variations of snow deposition after each storm for two consecutive winters, so defining the snow input system of the hydrologic cycle. The winters sampled (1969-70, 1970-71) represent a wide range of probable conditions. A related goal is the development of a climatology of winter storms. The final objective is to estimate snow deposition over a west coast midlatitude mountain after a storm. Input to the deterministic model which is evolved is restricted to precipitation and temperature data measured at the base of the mountain. All measurements are made on Mount Seymour, British Columbia, within a carefully structured experimental design using a double stratified random sampling scheme. Measurements are confined to a partly forested terrain segment of constant aspect and slope. Precipitation data are presented for open areas at 12 elevations from 120 m to 1260 m for 138 storms. These include data for 82 snow storms, where additional measurements are made within defined positions of the forest. Frequent net snow accumulation measurements are also made of the snowpack. Continuous temperature measurements at six elevations and on a TV mast define the thermal regime during storms. Several types of snowline are recognised and their elevations monitored every few days. The first objective cannot easily be achieved because simple empirical relationships between net snow accumulation and elevation are not reliable on a west coast midlatitude mountain. This is a consequence of the formation of a snow wedge on -the mountain, whose shape and slope is largely controlled by the frequency of winter storm types, except at the end of the season, or at low elevations, where melt processes are important. Snow accumulation in the forest can be estimated from that in the open with good precision, provided the snowpack is greater than 100 cm water equivalent. Snow deposition from each storm increases with elevation in wedge like form. The new snowlines and shape of this new snow wedge are mainly determined by the orographic increase in precipitation, and by the elevation of the freezing level. Large fluctuations of the freezing level among and within storms are a feature of west coast midlatitude mountains. Summation of snow deposition from each storm defines the total winter snow input to the snowpack (the second objective). This input also increases with elevation in wedge like form, hence explaining, with snow melt, the similar distribution of net snow accumulation. Contrary to earlier findings, total winter precipitation increases linearly with elevation, with no evidence of a consistent storm maximum at intermediate elevations. The input of water by rime is indexed, and found to be substantial. Ways of improving the efficiency of the sampling network of this study are proposed. The climatology of winter storms (the third objective) is developed from surface synoptic maps and upper air data by examining storm types, tracks, freezing levels and atmospheric fluxes of water vapour. The different snow regime of the two studied winters is explained in terms of this climatology. The relative importance of storm type in providing snowfall is assessed for each elevation on Mount Seymour. Good agreement is found when the deterministic model, which is developed to estimate storm snow deposition variations with elevation as in the final objective, is tested by comparing simulated snow deposition with independent data. Confidence limits about the predicted estimates are difficult to assess, but do not appear to be small. Throughfall of snow in the forest is predicted from that in the open with the relationships changing with elevation and storm characteristics. Evidence is presented that management of the seasonal snow cover on west coast midlatitude mountains is likely to be most effective at intermediate elevations. / Arts, Faculty of / Geography, Department of / Graduate

Graduation date: 1995

Thesis (Ph. D.)--Central Queensland University, 2001. / Title from PDF title page (viewed on July 2, 2005). Includes bibliographical references (p. 344-369).

xi, 114 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Different models have been proposed for the "drumbeat" earthquakes that accompanied recent eruptive behavior at Mount St. Helens. Debate continues as to whether seismicity is related to brittle failure during the extrusion of solid dacite spines or is the result of hydrothermal fluids interacting with a crack buried in the volcanic edifice. My model predictions of steady-state conduit flow confirm the strong control that degassing exerts on eruptive behavior. I discuss the necessary role of degassing for extruded material to attain the high density (low vesicularity) of the observed spine material and discuss the implications for generating seismicity. A brittle-failure source of seismicity requires that the gouge elastic properties accommodate some strain, since the magma compressibility in the upper conduit is too low to do so on its own. I also report on a novel method for generating high-resolution digital elevation models of fault surface textures. / Committee in Charge: Dr. Alan Rempel, Chair; Dr. Katharine Cashman; Dr. David Schmidt

In November, 2006, a storm generated a minimum of 34 cm of precipitation in six days, triggering debris flows in many of the drainages on all sides of Mount Hood, Oregon. Of the eleven drainages surveyed, seven experienced debris flows; these include the White River, Salmon River, Clark Creek, Newton Creek, Eliot Creek, Ladd Creek and Sandy River basins. Flows in the White River, Eliot Creek, and Newton Creek, caused major damage to bridges and roadways. Initiation elevations averaged around 1,860 meters. Initiation zone material was predominantly sand (45-82%) with gravel (15-49%) and had few fines (3-5%). Four debris flows were triggered by landslides caused by undercutting of the river banks. Three developed through coalescence of multiple small debris flows within major channels and were termed "headless debris flows". Physical and morphological characterization of source areas was used to assess factors controlling debris flow initiation. Although findings indicate that all major drainages on Mount Hood are capable of producing debris flows, drainages with direct connection to a glacier, low percentages of vegetation, and moderate gradients in the upper basin were the most susceptible. Among basins not having debris flows, neither the Zigzag River nor Polallie Creek have a direct connection to a glacier, And the Muddy Fork and the Coe both have high percentages of vegetated slopes. The material in the upper basin of the Muddy Fork is predominately rock making initiation there weathering-limited. Additionally, the Muddy Fork and the Zigzag have two of the steepest gradients on the mountain. This pattern suggests that material there is regularly transported downstream through normal fluvial processes rather than building up to be catastrophically removed through debris flow processes.

Debris flows caused by heavy rains occurred in November of 2006 on several Cascade volcanoes. Mt. Adams experienced debris flows in seven of eighteen drainages including Adams Creek, Big Muddy Creek, Lewis Creek, Little Muddy Creek, Muddy Fork, Rusk Creek and Salt Creek. Six debris flows occurred on the northeast side of the mountain. A landslide initiated one debris flow, three were initiated by heavy water flow and in channel landslides, and three were initiated by a coalescence of eroded channels (headless debris flows). Four pre-2006 debris flows were found in the Cascade Creek, Crofton Creek, Hellroaring Creek and Morrison Creek drainages. Every 2006 debris flow initiated in Quaternary glacial drift. Attributes of the drainages were investigated to determine differences between drainages with debris flows and those without. The upper basins of drainages with debris flows averaged 37% glacial coverage, 29% bedrock and 35% unconsolidated material. The upper basins of drainages without debris flows without averaged 12% glacial coverage, 63% bedrock, and 25% unconsolidated material. All of the drainages with debris flows were directly connected to a glacier, opposed to only 36% of the drainages without debris flows. Drainages with debris flows averaged 18% slopes above 33°, 10% vegetation, a gradient of 0.38, a Melton's Ruggedness Number of 0.62, an average annual rainfall of 2.16 m, and -52% glacier lost between 1904-2006. The upper basins of drainages without debris flows averaged 11% slopes above 33°, 18% vegetation, a gradient of 0.31, a MRN of 0.58, an average annual rainfall of 2.38 m, and -41% glacier lost between 1904-2006. A multiple logistic regression was performed to determine factors with highest influence on predicting the probability of a debris flow. Influencing factors were percent glacial coverage and average annual rainfall. They predicted the 2006 debris flows with an 89% accuracy rate. This model was used to produce a debris flow hazard map. Due to the number of Cascade volcanoes that experienced debris flows as a result of the November 2006 storm, data of this type could be combined from multiple mountains to construct a general Cascade Mountain debris flow hazard model.

Biodiversity patterns of butterflies and moths are investigated on the southwestern slope of Mount Cameroon, the only continuous elevational gradient of near-pristine forests in the Afrotropics. Three distinct seasons between 2014 and 2017 are sampled by two standardised methodologies (i.e., bait-trapping and manual catching of selected groups of moths at light). First, the effects of seasonality and forest habitat associations on butterflies and moths are investigated in the lowland rainforest. Then, the impacts of elephant-made natural disturbances on tree, butterfly, and moth diversities at mid-elevations is evaluated. The thesis also includes faunistic records of species never reported from the area, combining them with life history notes on selected taxa and species description of nine new species of Alucita. Finally, the last chapter focuses on the biodiversity of birds, trees, and butterflies in the last large patch of coastal forest of the studied area, and discusses its current conservation status.

A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Engineering. / The viability of introducing a Surface Mount production line is chiefly determined by the reliability characteristics of the components being used. Surface Mount Technology (SMT) is entirely new and although related to traditional through-hole processes, requires different components, assembly techniques and design methods. The purpose of the literature survey is primarily to determine whether surface mount components meet today's industrial requirements with respect to their manufacturing reliability and availability. A brief review of the evolution of SMT is also presented. This study finds that the implementation of SMT should be given highest priority by manufacturing companies in order to maintain their share of the marketplace. Surface Mount Technology embodies a totally new automated circuit assembly process, using a new generation of electronic comporents: surface mounted devices (SMDs). Smaller than conventional components, SMDs are placed onto the surface of the substrate. From this, the fundamental difference between SMD assembly and convencional through-hole component assembly arises; SMD component positioning is relative, not absolute. When a through-hole component is inserted into a pcb, either the leads go through the hales or they don't. An SMD, however, is placed onto the substrate surface, it's position only relative to the solder lands, and placement accuracy is therefore influenced by variations in the substrate track pattern, component size, and placement machine accuracy. Other factors influence the layout of SMD substrates. For example, will the board be a mixed-print ( a combination of through-hole components and SMDs) or an all-SMD design? Will SMDs be placed on one side of the substrate or both? And there are process considerations like what type of machine will place the components and how will they be soldered? This project describes in detail the processes involved in setting up an SMT facility. A simulation program was developed to verify the viability of these processes. The simulation program was also applied to an existing SMT facility and together with developed optimization software, attempted to identify and resolve some of the major problems. All this was achieved, and the extent to which simulation could be used as an efficient production tool, was highlighted. / AC2017

This study is an effort to characterize the magma sources, plumbing system, and eruptive behavior of Mount Hood, a low-explosivity recharge-dominated volcano in the Oregon Cascades. The three manuscripts in this dissertation make use of melt inclusion data, phenocryst compositions, and whole rock petrology and geochemistry to build a schematic model of plumbing, mixing, and eruption at Mount Hood. Volatile contents in melt inclusions were measured by Fourier Transform Infrared Spectroscopy (FTIR) and Secondary Ion Mass Spectometry (SIMS). These measurements indicate that the pre-eruptive volatile contents at Mount Hood are comparable to concentrations in more explosive volcanoes, and do not sufficiently explain the low explosivity of Mount Hood. Measured H₂O contents were also used to test the validity of multiple different hygrometers. Various geothermobarometers were applied to the melt inclusions and phenocrysts from Mount Hood, and demonstrate that pre-eruptive temperatures increase by 100-150 ̊C immediately after mafic recharge, which occurs days to weeks prior to eruption and is accompanied by a 5-10 fold decrease in magma viscosity. Numerical simulations of magma ascent indicate that magma fragmentation is significantly delayed with this magnitude of pre-eruptive heating, which reduces the likelihood of explosive eruption. Analyses of amphibole demonstrate two markedly different populations, which correspond to different magma compositions, temperatures, and pressures. Pressure and temperature calculations were compared to other geothermobarometers to crosscheck the validity of these results and generally agreed well. Trace element concentrations in lavas, enclaves, and inclusions from Mount Hood confirm previous models for simple binary mixing at Mount Hood. A linear regression technique for extrapolating the major element contents of the mixing endmembers works acceptably well to characterize the trace element budgets of these endmembers. Additionally, we observe that the "recharge filter" that is responsible for the compositionally monotonous lavas at Mount Hood is also the likely cause of long-term low explosivity, and is indicative of a two-part magma plumbing system that may be a general model for a number of other recharge-dominated arc volcanoes. The results presented in this dissertation, in concert with previous results by other authors, converge on a generally consistent model for the production, hybridization, and eruption of intermediate lavas at Mount Hood and elsewhere. / Graduation date: 2012 / Access restricted to the OSU Community at author's request from Sept. 16, 2011 - March 16, 2012