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Spatial and temporal changes in stream network topology : post-eruption drainage, Mount St. Helens /Parsons, Michael Raymond. January 1985 (has links)
Thesis (Ph. D.)--Oregon State University, 1985. / Typescript (photocopy). Includes bibliographical references (leaves 168-175). Also available online.
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Sediment transport by wind : saltation, suspension, erosion and ripples /Anderson, Robert Stewart. January 1986 (has links)
Thesis (Ph. D.)--University of Washington, 1986. / Vita. Bibliography: leaves [157]-174.
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Changes to in-stream turbidity following construction of a forest road in a forested watershed in West VirginiaSharp, William Frank. January 2007 (has links)
Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains ix, 79 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 41-46).
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Development of a Cavitation Erosion Resistant Advanced Material SystemLight, Kendrick H. January 2005 (has links) (PDF)
No description available.
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Análise comparativa da evolução das boçorocas nos anos de 1962 e 1999 nos municípios de Pompéia e Oriente SP /Cruz, Carla da. January 2001 (has links)
Orientador: Joel Barbujiani Sígolo / Banca: Leandro Eugenio da Silva Cerri / Banca: Paulo César Fonseca Giannini / Resumo: Realizou-se neste trabalho a análise comparativa entre boçorocas existentes no ano de 1962 com as do ano de 1999, enfocando sua evolução, estabilização e reutilização nos municípios de Pompéia e Oriente, localizados no Planalto Ocidental Paulista, Esta análise constituiu-se de fotointerpretação de fotografias aéreas da área de estudo, na escala 1:25. 000, e trabalhos de campo que incluíram o cadastramento e mensuração das boçorocas do primeiro período, e suas alterações recentes ao longo destes anos, bem como novas boçorocas na mesma área para efeitos de comparação e atualização. Os municípios estudados, ficam entre as cidades de Tupã e Marília, área de aproximadamente 20 km , constituída geologicamente pelas Formações Marília e Adamantina pertencentes ao Grupo Bauru e geomorfologicamente pelos Planaltos Residual de Marília e Centro Ocidental. A metodologia aplicada neste caso constou de levantamento geológico expedito, análise pedológica parcial e delimitação da compartimentação geomorfológica. Estes elementos foram analisados a luz das atuais condições climáticas, da atual vegetação e do recente uso e ocupação do solo e suas implicações com as boçorocas anteriores e as atuais. Esta análise implicou na proposta de estabelecer a interação entre as características naturais associadas às atividades antrópicas e ao processo erosivo implantado na área em questão. Obteve-se com a comparação dos resultados à influência conjunta dos fatores citados na ocorrência de erosões e na permanência do processo erosivo nos municípios estudados, verificando-se modificações nas boçorocas de 1962, tendo sido utilizados meios de contenção e de reutilização dessas feições erosivas. Em outros casos, as boçorocas apresentaram quadro de estabilização natural. Demonstrou-se com os dados obtidos que a mudança...(Resumo completo, clicar acesso eletrônico abaixo) / In this work in two cities, Pompéia and Oriente, located in São Paulo State, a comparative analysis of gully erosion verified in 1962 and 1999was carried out to verify their development, stabilization and reutilization. The tools used for the analysis were photo interpretation of air photographs of the area studied, using the 1:25.000 scale, as well as works in loco including register and measurement of the gully erosion in the first period and its recent changes, together with further erosion in the same area, aiming additional comparison and updating. The two towns object of this study are located between the cities: Tupã and Marília, in an area of around 20 km2 , with Geologic Formations - Marília and Adamantina - belonging to the Bauru Group, and Geomorphologic Formation with Plateaus - Central Western and Planalto Residual in Marilia. The approach used consisted of expeditious geologic raising, partial Pedologic analysis, and delimitation of geomorphologic compartments. These were analysed in the light of the current climate conditions, woods and recent soil utilization and occupation with their implications for the previous and present gully erosion. The proposal of this analysis was to establish the interaction between the natural conditions and human activities and the erosive process implemented in the area. The comparison of results showed the influence of both factors on the erosion and running erosive process in the towns focused, with changes in the gully erosion of 1962, where means of contention and reutilization were used. In other cases the gully erosion showed natural stabilization. As a result of the intense erosive process in the 60s, the Aguapeí River Basin shows obstruction impairing the water flow. In some affluents several levels of terrace plain of sediments narrow the channels and only few centimeters of water flow...(Complete abstract click electronic access below) / Mestre
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FACTORS AFFECTING EROSION ON A NATURAL GAS PIPELINE IN THE CENTRAL APPALACHIANSHolz, Dan 01 January 2009 (has links)
High fuel prices have created an economic climate in which oil and gas development is increasingly profitable, and consequently, is increasing rapidly in the United States. The development includes drilling new wells and expanding the pipeline network to deliver gas and oil. This is especially true in the northern Appalachian region where the relatively undeveloped Marcellus shale formation is located. The Marcellus formation has been called a "super giant" gas reservoir possibly containing 50 trillion cubic feet of recoverable natural gas (Harper, 2008). In Pennsylvania alone, over 375 wells targeting the Marcellus shale formation have been approved between 2003 and the end of 2007. However, environmental impacts from well pads and pipelines are relatively unknown. Sediment concentrations and yields were measured from four sections of an in-road pipeline in the Monongahela National Forest in Tucker County, West Virginia during summer and fall 2007 and spring 2008. The objectives of this study were to determine the influence of vegetation cover and precipitation characteristics on sediment concentrations in runoff and sediment yields from the in-road pipeline, and to compare sediment yields to forest roads. Poorly vegetated pipeline sections produced 30.92 kg of sediment throughout the study compared to 13.49 kg for the well vegetated sections. Despite this, percent vegetative ground cover had no statistically significantly effect on sediment concentrations or yields except during very intense storms. Several precipitation characteristics, especially intensity, played a significant role in explaining sediment yields and concentrations. Precipitation patterns changed with seasons, and therefore, sediment concentrations and yields varied significantly by season. The most intense storms occurred during the summer months, which is when most soil loss also occurred. Erosion rates from the pipeline were greater than from undisturbed or well-managed forest plots, but were less than rates reported for logging and skid roads when normalized for rainfall. The reduced erosion rates suggest that routing new pipelines along closed roads may be a good method to reduce erosion compared to clearing new pipeline rights-of-ways. To further reduce erosion potential, steps in the installation process that expose mineral soil should be timed to avoid periods of intense rainfall.
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Soil conservation with leguminous cover crops following deforestation of tropical steeplandArevalo-Mendez, Ignacio January 1998 (has links)
The steeplands of Central America are being systematically deforested as population pressure dictates a need for an increase in subsistence agriculture. The combined effect of high rainfall and lack of conservation measures leads to high levels of soil erosion. In order to assess sustainable soil conservation technology, research was conducted in the mountainous agricultural area of Guinope, Honduras. Runoff and soil loss from a number of plots that were established on various ground slopes and under different land uses were measured during the 1994 and 1995 seasons. Natural and fired woodland were assessed to provide an indication of both baseline conditions and those associated with the initial stage of deforestation. Against these, the impacts of agriculture involving maize - Zea mays L.- with and without two leguminous cover crops - Mucuna sp. and Canavalia ensiformis (l)DC. - were assessed on ground sloping at 6, 11 and 18 degrees. Seasonal runoff under natural pine forest is shown to be 10 % that of maize agriculture on similar slopes while fired forest is 49 %. Of the cover crops, after a second year Mucuna is the most protective when intercropped with maize, giving runoff on 18 degree slopes which is 47 % that of maize grown by itself, compared with 51 % for Canavalia. On 11 degree slopes, Canavalia offers greater protection but here the difference between the two cover crops is marginal Soil erosion can be shown to be a function of ground slope. For maize grown by itself, soil losses from 6 and 11degree slopes are 13 % and 23 % those from 18 degree slopes. On two years of research Canavalia is more stable in giving protection. On 18 degree slopes, soil loss where Mucuna is intercropped is 43 % that under maize alone while for Canavalia it is 47 %. By comparison, the natural forest loses much less than 1 % that of the maize fields. This study clearly shows the vulnerability of steep lands that are being clear-felled. It also demonstrates the considerable advantages of using extensive green soil conservation technology in reducing soil erosion and prolonging the usefulness of land. This extends to relieving the pressure on virgin forest in a situation where population growth discourages long periods fallow as part of a form of shifting cultivation.
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The engineering geology and stability of the rapidly alternating limestone and mudrock sea cliffs of GlamorganGrimes, John January 1986 (has links)
Processes, mechanisms and parameters significant to instability have been identified from an investigation which has included 1) Geomorphological mapping and appraisal. 2) Field Monitoring. 3) Quantitative assessement of rock mass geometry, mineralogy, engineering properties and physical/physico-chemical behaviour. The north coast of the Bristol Channel is exposed to severe marine attack. Weak lithologies are exploited and the cliffs undermined. Principal failure modes recognised were toppling and vertical translation. Thermal gravimetry indicated allotropy of sulphide minerals. The least stable forms were identified in the more calcareous mudrocks, and a laboratory leaching experiment demonstrated that weatherability was greatest in such mudrocks. Pyrite oxidation was shown not only to enhance carbonate leaching, but to degrade the clay minerals and induce rehydration of the double layer. Uniaxial compressive strengths of representative mudrocks were determined for a range of moisture contents. Mean values varied between 5 and 64 MPa. An investigation into deformation anisotropy of a clay shale is also recorded. Meso and micro scale carbonate filled discontinuities are apparent in the limestones. Hoek & Brown's criterion was used to characterise results of a programme of strength testing. Average uniaxial compressive strength of the intact limestone was 234 MPa. In the field, many major discontinuities were identified as tensile in origin. Results from shear tests along limestone tension fractures could not be adequately represented by Barton's equation. A power relationship between shear strength and normal stress gave good correlation. Leaching, moisture and temperature movements, freeze-thaw and pressure release all act to impair stability. Extreme weather was shown to trigger failure. Limiting equilibrium analyses of toppling showed that torsional shear strength mobilized along the failure surface in the plane of toppling contributed significantly to forces resisting toppling. Both local masonry protection and pre-split blasting are recommended as viable expedients in protection and stabilization works.
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Compartimentação do meio físico, evolução morfológica e aspectos morfotectônicos em São Thomé das Letras (MG)Marques Neto, Roberto [UNESP] 29 October 2007 (has links) (PDF)
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marquesneto_r_me_rcla.pdf: 2544757 bytes, checksum: c23c3787ee6420768ab406cae71bd6c2 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O propósito da presente dissertação consiste na determinação de unidades de paisagem para o município de São Thomé das Letras (MG), no estudo da evolução morfológica da área e na apreciação de aspectos morfotectônicos. O cumprimento dos objetivos estipulados demandou uma série de dispositivos analíticos que se coadunaram para a interpretação da fisiologia da paisagem e para o discernimento de diferentes unidades paisagísticas representadas em documento cartográfico de síntese. O estudo da evolução morfológica demandou a avaliação de elementos do quadro genético-evolutivo regional como meio para o entendimento dos processos operantes em âmbito local. A pesquisa focalizou a ocorrência e posicionamento de diferentes superfícies de erosão na área de estudo, diferenciando remanescentes relacionados à Superfície Sul-Americana, do Terciário Inferior, de modelados de dissecação mais recentes, de idade plio-pleistocência. A esta etapa se somou, com ênfase, estudos interessados na evolução morfológica levada a efeito durante o Quaternário em consonância com as oscilações climáticas que marca o referido período, o que se deu por meio do estudo de processos de pedimentação recente e dos depósitos correlatos, da avaliação da cobertura vegetal atual e dos fenômenos cársticos operantes, também sendo estimada a evolução do relevo com enfoque na estrutura, que confere tipicidade apalachiana para a morfologia local e regional. No tocante aos aspectos morfotectônicos, a pesquisa se valeu da análise do relevo e da drenagem, enfando os fenômenos neotectônicos com base na identificação de feições morfológicas indicativas (shutter ridges, capturas, migração lateral de cursos dágua, canais fluviais com trechos excessivamente retilíneos, etc.) e na identificação e interpretação dos principais lineamentos. Os estudos morfotectônicos... / The aim of this present dissertation consists in the determination of landscape unity for the town of São Thomé das Letras (MG), in the study of the area morphological evolution and appreciation of morphotectonic aspects. The fulfilment of stipulated purpose demanded a serie of analytical device that were gathered for the comprehention of landscape phisiology as well as the understanding of different landscape unities represented in graphic-chart document of synthesis. The study of morphological evolution demanded the evaluation of components the regional genetic-evolutive chart as so as to understand the operating process in local range. The research focused the occurence and status of different erosion surface in the studied area, differenciating remainders related to Superfície Sul-Americana of low Terciary, of latest dissection molded, of plio-pleistocene age. To such stage, with emphasis, was added studies interested in the morphological evolution effectuatedduring the Quaternary in consonance with climatic fluctuations that mark the referred era, which happened by means of process study of recent pedimentation and correlated deposits from evaluation of current vegetal covering and operating carstic phenomenon, also evolution of relief beig estimated focusing the structure, that grants appalachian tipicality to regional and local morphology. Regarding the morphotectonic aspects, the research turned to the relief analisis and drainage emphasizing the neotectonic phenomena based on identification of indicative morphological features (shutter ridges, captures, water-course lateral migration, river channel with excessively right-lined streches, etc.) and identification and interpretation of main lineages. The morphotectonic studies were subsidized by measuring the geomorphic rate useful for estimating neotectonic effects, notoriously the asymmetry Factor of Drainage Basins... (Complete abstract click electronic access below)
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Factors associated with dental disease and development in preschool childrenDuncan, Karen January 2000 (has links)
No description available.
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