Dissertations / Theses on the topic 'Surfaces – Erosion'
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Kaye, Peter Langford. "The erosive cleaning of surfaces." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364393.
Full textMarques, Neto Roberto [UNESP]. "Compartimentação do meio físico, evolução morfológica e aspectos morfotectônicos em São Thomé das Letras (MG)." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/95587.
Full textConselho 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)
Thomas, Petros. "Novel optical studies of ion-erosion, growth, and diffusion on metal surfaces /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
Full textBaugh, Nicole Faith. "Fluvial Channels On Titan." Thesis, The University of Arizona, 2008. http://hdl.handle.net/10150/193368.
Full textMarques, Neto Roberto. "Compartimentação do meio físico, evolução morfológica e aspectos morfotectônicos em São Thomé das Letras (MG) /." Rio Claro : [s.n.], 2007. http://hdl.handle.net/11449/95587.
Full textBanca: Archimedes Perez Filho
Banca: Francisco Sérgio Bernardes Ladeira
Resumo: 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... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: 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)
Mestre
Cornejo, Marina Inés [Verfasser]. "Pattern formation on Si surfaces by low-energy ion beam erosion / Marina Inés Cornejo." Aachen : Shaker, 2011. http://d-nb.info/1070150231/34.
Full textFreitas, De Abreu Marcio. "Experimental Study of Metallic Surfaces Exposed to Cavitation." Thesis, KTH, Materialvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-231937.
Full textCornejo, Marina Inés Verfasser], and Frank [Akademischer Betreuer] [Mücklich. "Pattern formation on Si surfaces by low-energy ion beam erosion / Marina Inés Cornejo. Betreuer: Frank Mücklich." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2011. http://d-nb.info/1051326745/34.
Full textCornejo, Marina Inés [Verfasser], and Frank [Akademischer Betreuer] Mücklich. "Pattern formation on Si surfaces by low-energy ion beam erosion / Marina Inés Cornejo. Betreuer: Frank Mücklich." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:291-scidok-42503.
Full textLevandovsky, Artem. "Structure and dynamics of interfaces in the epitaxial growth and erosion on (110) and (100) crystal surfaces." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3731.
Full textTitle from document title page. Document formatted into pages; contains vii, 129 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.
Tabor, Nathan Kyle. "Development of solution techniques and design guidelines for equestrian trails on public lands." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5023.
Full textThe entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on November 6, 2007) Includes bibliographical references.
Hermansson, Jakob, and Emma Wahlström. "Materialval för minskat slitage av sandformningsverktyg." Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-13776.
Full textAt Volvo Group Trucks Operations (GTO) in Skövde, cylinder blocks, cylinder heads and flywheels are manufactured through sandcasting. As the forming tools that forms the sand forms are filled with sand, wear occurs where the sand particles hit the tool surface. The forming tool thus needs to be regularly maintained. The aim of this study is to evaluate alternative materials that the forming tools can be manufactured in to reduce wear, and thereby reducing costs by extending maintenance intervals. The problem is analyzed and a literature study on erosive and abrasive wear is carried out. A number of materials are presented as suitable candidates based on the literature study, material charts and discussion. Material samples are tested using a standard method for solid particle erosion using gas jets. Results from previous empirical studies indicate that erosion is strongly influenced by material properties such as hardness and toughness but also the angle of impingement and velocity of the erosive particles.The erosion test is performed at 30 and 90 degree angle of impingement. The test shows that the softer steel, Holdax and Sverker 21 have higher resistance to erosion at low angles of impingement and the harder steel Nimax has higher resistance at high angles of impingement. Nimax is considered a suitable material for the forming tool, as Nimax has the overall lowest erosion rate when adding the total erosion over both angles of impingement. Nimax has the lowest erosion rate at 30 degrees angle and is also considered to have good resistance to erosion at 90 degrees angle. Recommendation is given on repeated erosion tests to validate the results. There are also recommendations regarding material testing in the forming tool to see if a material change would lead to savings. Examination of possibilities to make changes in the sand filling process, altering angle of impingement between the sand blown and the forming tool as well as air pressure is recommended.
Bragança, Mário Teixeira Rodrigues. "Superfícies de erosão do setor centro-oriental da Bacia do Rio Paracatu, no Estado de Minas Gerais." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/8/8135/tde-29082012-091211/.
Full textThe regularity of the relief of Paracatu Catchment inserted into Atlantic Shield, is preserved in weathering and erosion resistant rocky layers. It is organized in a stratigraphic column wich keeps its original conditions of deposition with recordings of small dimension crustal movements, allowing the ideal theoretical conditions for the study of erosion surfaces. To associate the evolution of geomorphology of Paracatu River Catchment to material and structure, looking for explanations to the preservation of erosion surfaces in the arrangement of sedimentary successions, unconformities and erosive plateaus were the conditions to identify and describe four surfaces wich record the regional morphological evolution: Tabular Plateau Surface, Tabular Plateau Surface with Dissected Valleys, Low Tableland with Ravined Pedments and Dissected Valleys Surface, and Paracatu River Fluvial Plain Depression Surface. A broad fieldwork through a general and regional approach, followed by an intense bibliographic review and manipulation of topographic and geologic maps and its manipulation in GIS, through a development of a Digital Terrain Model and many topographic profiles, allowed to describe the relief in suggesting the reconstitution of the geomorphological history of the study area, resulting in an erosion surfaces map. The origin of this erosion surfaces can be correlated to four tectonic cycles, that elevated the Brazilian Platform since the Cretaceous until Pleistocene, with drainage incision and dissection of the landscape.
Santos, Antonio Carlos de Araújo. "Morfologia e topografia de superfícies de aço inoxidável duplex UNS S32205, submetidas à erosão por impactos de partículas de alumina em fluxo de ar." Universidade do Estado do Rio de Janeiro, 2015. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=9392.
Full textOs aços inoxidáveis duplex vêm sendo cada vez mais utilizados em aplicações que demandam maior resistência à corrosão que os aços inoxidáveis tradicionais. Suas aplicações em estruturas ao ar livre, ou submersas, motivam estudos sobre seu desempenho em variadas situações, como no caso de exposição ao desgaste erosivo.O presente trabalho estuda os efeitos da erosão por impacto de partículas sólidas em superfícies de amostras de um aço inoxidável duplex UNS S32205, tanto do ponto de vista morfológico quanto do topográfico. Superfícies de amostras polidas e posteriormente submetidas a ataques erosivos com partículas de alumina em fluxo de ar, foram examinadas por microscopia eletrônica de varredura, para verificação das formas de desgaste obtidas, e submetidas a ensaios de rugosidade, para determinação do perfil e avaliação da evolução do processo erosivo. Foi feito um exame mais detalhado de formatos de crateras, para comparação com mecanismos propostos em modelos descritos na literatura e com resultados de simulações pelo método dos elementos finitos. Nesse aspecto, o método utilizado mostrou-se tão eficaz quanto aos métodos tradicionais de estudos balísticos com uma só partícula, além de mais abrangente e econômico. As medidas de rugosidade superficial e as informações estatísticas derivadas sinalizaram a possibilidade de utilização dessa ferramenta para avaliar as condições de efetiva perda de massa, que caracterizam a erosão.
Duplex stainless steels are being increasingly used in applications that require a greater corrosion resistance than traditional stainless steels. Its applications in both, outdoor or submerged structures, motivate the studies on its performance in various situations, as in the case of exposure to erosive wear. This work studies the effects of erosion by impact of solid particles on surfaces of samples of duplex stainless steel UNS S32205, from the point of view of both aspects, morphological and topographycal. Polished surfaces of the samples were subjected to erosive attacks by alumina particles in air flux, with different exposure times. These were examined by scanning electron microscopy, looking at the forms of wear obtained and the surfaces roughnesses were measured, aiming to follow the evolution of the erosive process. It was made a more detailed examination of craters, for comparison with the proposed mechanisms in models described in the literature and with the results of simulations by the finite elements method. In this aspect the method proved to be as effective as the traditional methods of ballistic studies using single particles, as well as to be more comprehensive and economic. The measures of surface roughness and the statistics from the derived data signaled the possibility of use of this tool to evaluate the beginning of the effective loss of mass, which characterizes the erosion.
Bouzaida, Dalel. "Caractérisation et suivi des états de surfaces éolisés en Tunisie pré-saharienne : approches stationnelle et spatiale." Thesis, Lyon 2, 2012. http://www.theses.fr/2012LYO20016.
Full textUnder the effect of climate change, new landscapes reflecting the interactions between natural processes and human inappropriate activities appeared in Southern Tunisia. Wind erosion is one of the most important events. In this thesis, operational and validated methodology (the permanent transect method) has been developed for the characterization of Surfaces States and quantification of the sediment balance of a 500 m length transect over a period of two years. On spatial scale, mapping of the Aeolian units of deflation, transit and sand deposit was developed. Radiometric characterization of sand accumulations was then tried for the detection of changes that occurred within more than 35 years.At the site level, the permanent transect method enabeled the diachronic sedimentary balance calculation and the comparison of the Surface states changes. The single observation of these areas is insufficient to determine the real eolian process of a region ; moreover it induces to errors of interpretation on the sedimentary process.At the spatial scale, maps of the Aeolian units enabeled to determine the vulnerability of the environment to the process of deflation, transport and deposition. In addition, the characterization of sand accumulations by radiometric indices is not obvious within 30 m resolution images. The statistical analyses have shown that Color Index is the most indicated for this type of study. The calculation of the rates of change between two successive dates images allows to estimate the sandy spaces evolution and their spatial distribution for more than 35 years
Duncan, S. "Ion erosion in surface analysis." Thesis, Loughborough University, 1985. https://dspace.lboro.ac.uk/2134/28023.
Full textWheeler, David William. "Solid particle erosion of CVD diamond coatings." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342748.
Full textСемко, Петро Володимирович, and Petro Semko. "Дослідження автоматизованої системи підготовки поверхонь деталей до нанесення покриттів." Master's thesis, Тернопільський національний технічний університет ім. І. Пулюя, Факультет прикладних інформаційних технологій та електроінженерії, Кафедра автоматизації технологічних процесів і виробництв, 2019. http://elartu.tntu.edu.ua/handle/lib/29795.
Full textВ даній кваліфікаційній роботі розроблено автоматизовану лінію, для реалізації технологічного процесу підготовки поверхонь деталей до нанесення лакофарбових та гальванічних покриттів. Автоматизована дільниця підготовки поверхонь до нанесення покриття забезпечує наступні технологічні переходи: Очистка поверхонь. В операцію очистки включать наступні операції, - видалення механічних забруднень, обезжирення та видалення хімічних забруднень (окиси, іржа, поверхневі сполуки матеріалу і.т.ін.). Операція очистки проводиться хімічними методами. Пасивування поверхонь. Операція пасивування повинна забезпечити надійність отриманої чистої поверхні, запобігати міжопераційному окисленню перед нанесенням основного покриття деталей. Промивка поверхонь (основна та міжопераційна). Для забезпечення чистоти поверхні від речовин попередніх технологічних переходів. Сушка поверхонь деталей. Видалення залишкової вологи та активних розчинів з поверхні деталей для забезпечення мінімального часу контакту поверхні з вологою, яка сприяє корозії та окисленню матеріалу. Регенерація розчинів. Регенерація активних розчинів їх очистка забезпечить економію витрат речовин, що в результаті збільшить рентабельність її використання. Чистота розчинів впливає на якість проходження хімічних реакцій, скорочує їх тривалість. Міжопераційне транспортування. Для забезпечення транспортування деталей в автоматизованому режимі роботи між позиціями технологічних переходів. В проекті автоматизованої дільниці передбачено загальну систему керування, яка здійснює загальний контроль і управління лінією по основним параметрам.
In this qualification work an automated line has been developed for the implementation of the technological process of preparing the surfaces of parts for the application of paint and electroplating coatings. The automated surface preparation site for coating provides the following technological transitions: Surface cleaning. The cleaning operation will include the following operations - removal of mechanical impurities, degreasing and removal of chemical contaminants (oxides, rust, surface compounds of the material etc.). The cleaning operation is carried out by chemical methods. Passivation of surfaces. The passivation operation must ensure the reliability of the clean surface obtained, and prevent the inter-operative oxidation before the main coating of the parts is applied. Surface washing (basic and inter-operative). To ensure the purity of the surface from the substances of the previous technological transitions. Drying of parts surfaces. Removal of residual moisture and active solutions from the surface of the parts to ensure minimum contact time of the surface with moisture, which promotes corrosion and oxidation of the material. Regeneration of solutions. The regeneration of the active solutions of their purification will save the cost of substances, which as a result will increase the profitability of its use. The purity of the solutions affects the quality of the passage of chemical reactions, reducing their duration. Inter-operative transportation. To ensure the transportation of parts in an automated mode of operation between positions of technological transitions. The design of the automated section provides a common control system that performs general control and line control over the main parameters.
РЕФЕРАТ 3 АBSTRACT 4 ЗМІСТ 5 ВСТУП 9 1. АНАЛІТИЧНА ЧАСТИНА 10 1.1 Підготовка поверхні до нанесення покриття 10 1.2 Методи підготовки поверхні 14 1.3 Хімічні методи 16 1.3.1 Знежирення 16 1.3.2 Знежирення органічними розчинниками. 17 1.3.3 Лужне знежирення. 18 1.3.4 Емульсійне знежирення 24 1.3.5 Контроль і коректування розчинів у ваннах знежирення. 25 1.4 Травлення чорних металів 26 1.5 Механічні методи очистки поверхонь 27 2 НАУКОВО-ДОСЛІДНА ЧАСТИНА 29 2.1 Кавітаційні ефекти й механізми ультразвукового очищення 29 2.2 Виникнення акустичної кавітації в середовищі очищення 32 2.3 Пульсації пухирців у звуковому полі та їх вплив на поверхню очищення 34 3 ТЕХНОЛОГІЧНА ЧАСТИНА 45 ТЕХНОЛОГІЇ ОЧИСТКИ ПОВЕРХОНЬ ВІД ЗАБРУДНЕНЬ ПЕРЕД НАНЕСЕННЯМ ПОКРИТТІВ 45 3.1 Устаткування та процеси підготовки поверхонь деталей до нанесення покриття 45 3.2 Знежирення 46 3.3 Травлення 47 3.4 Створення проміжних покриттів 48 3.4.1 Фосфатування 48 3.4.2Пасивування 48 3.4.3 Хроматування 48 3.4.5 Утилізація олій 49 3.5 Технологія підготовки поверхонь для різних матеріалів 49 3.5.1 Для підготовки сталевої поверхні 49 3.5.2 Для підготовки оцинкованої поверхні. 49 3.5.3 Для підготовки поверхні алюмінію та його сплавів 50 3.6 Приготування розчинів для підготовки поверхонь 51 3.6.1 Знежирення, сполучене знежирення-травлення 51 3.6.2 Розчин для хімічного знежирення "ЕКОМЕТ-003" 51 3.7 Рекомендації з вибору розчинів знежирення 52 4 КОНСТРУКТОРСЬКА ЧАСТИНА 55 4.1 Устаткування для хімічної підготовки поверхні виробів під фарбування 55 4.1.1 Устаткування для підготовки поверхні методом занурення. 55 4.1.2 Устаткування для підготовки поверхні методом струминного обливу. 56 4.1.3 Устаткування для знежирення розчинниками. 62 4.2 Загальні вимоги до лінії підготовки поверхонь деталей для нанесення покриттів 64 4.3 Будова та склад лінії 65 4.4 Будова та принцип дії складових частин лінії. 66 4.5 Розміщення та монтаж лінії 71 4.6 Розробка автоматичної системи керування лінії підготовки поверхонь до нанесення покриття 74 4.7 Розробка та компоновка функціональної схеми автоматичної системи керування лінії 78 4.8 Блок процесорного комплекту. 80 5 СПЕЦІАЛЬНА ЧАСТИНА 85 САПР І РОЗРОБКА ПРОГРАМНОГО ЗАБЕЗПЕЧЕННЯ 85 5.1 Загальні відомості про систему команд КР1816ВЕ51 (МК51) 85 5.2 Група команд пересилання даних 89 5.3 Група команд арифметичних операцій 90 5.4 Група команд логічних операцій 91 5.5 Група команд операцій з бітами 91 5.6 Група команд передачі керування 91 6 ОБГРУНТУВАННЯ ЕКОНОМЧІНОЇ ЕФЕКТИВНОСТІ 94 6.1 Загальні положення по визначенню економічної ефективності. 94 6.2 Розрахунок витрат на виготовлення та використання модернізованої системи управління. 94 6.3 Розрахунок економічного ефекту від виготовлення та експлуатації приладу за розрахунковий період 105 6.4 Розрахунок ефективності капітальних вкладень. 106 7 ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІЯХ 108 7.1 ОХОРОНА ПРАЦІ 108 7.1 Правила безпеки при експлуатації обладнання лінії підготовки поверхонь 108 7.2 Заходи забезпечення електробезпечності електроустановки 109 7.2 БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІЯХ 113 7.2.1 Розробка заходів які зменшують небезпеку виникнення вибухів і пожеж на дільниці в цеху 113 7.2.2 Оцінка хімічної обстановки на підприємствах, що використовують СДОР в технологічних цілях 115 7.2.3 Поняття про хімічну обстановку на об’єкті та її оцінку 115 7.2.4 Методи оцінки хімічної обстановки на промисловому об’єкті 117 7.2.5 Особливості оцінки хімічної обстановки на хімічно небезпечному об’єкті 118 8 ЕКОЛОГІЯ 122 8.1 Актуальність охорони навколишнього середовища 122 8.2 Основні джерела забруднень гальванічного виробництва та обладнання для їх усунення 123 8.3. Заходи по усуненню шкідливих впливів гальванічного виробництва 128 ВИСНОВОК 131 ПЕРЕЛІК ПОСИЛАНЬ 135 ДОДАТКИ 140
Enriquez, Adriana Gomez. "Erodibilidade e tensão crítica de cisalhamento no canal de uma estrada não pavimentada situada em um Latossolo Vermelho-Amarelo." Universidade Federal de Viçosa, 2012. http://locus.ufv.br/handle/123456789/3628.
Full textThe erosion in unpaved roads associated with the runoff has negative implication in social, economic and environmental development of a region. Therefore the incorporation of techniques for prevention and control of erosion on these roads is important. The techniques developed for this purpose require knowledge of the indices of soil resistance to erosion, principally the soil erodibility and critical shear stress. In this context, the aim of this study was to determine the erodibility and critical shear stress in the channel of an unpaved road implanted in an Oxisol horizons B and C. Study was conducted on an unpaved road in Viçosa-MG, Brazil, where the indices were obtained using a runoff simulator installed on the channel road, which allows to estimate soil loss associated with different shear stress. The results obtained in each test was adjusted using simple linear regression models and, the models identity test proceeded to obtain a representative value of the indices for the study site, and to obtain the confidence interval associated with the erodibility, considering 95% of probability. The erodibility value determined for the horizon B was 0.0044 g cm-2 min-1 Pa-1, and its associated confidence interval with 95% probability was 0.0035 to 0.0053 g cm-2 min-1 Pa-1. The critical shear stress determined for this horizon was 7.61 Pa. The horizon C erodibility value determined was 0.0347 g cm-2 min-1 Pa-1, and its xv associated confidence interval with 95% probability was 0.0288 to 0.0406 g cm-2 min-1 Pa-1. The critical shear stress value for this horizon was 8.16 Pa.
A erosão em estradas não pavimentadas associada ao escoamento superficial interfere negativamente no desenvolvimento social, econômico e ambiental de uma região. Por isso é importante a incorporação de técnicas que visem a prevenção e o controle da erosão nestas estradas. As diferentes técnicas desenvolvidas para este fim requerem o conhecimento dos índices de resistência do solo ao processo erosivo, sendo a erodibilidade e a tensão crítica de cisalhamento os índices de maior importância. Neste sentido, objetivou-se com a realização deste trabalho, determinar a erodibilidade e a tensão crítica de cisalhamento no canal de uma estrada não pavimentada implantada nos horizontes B e C de um Latossolo Vermelho-Amarelo. O estudo foi realizado em uma estrada não pavimentada do município de Viçosa- MG, onde os índices foram obtidos utilizando um método de determinação direta com o uso de um simulador de escoamento instalado no canal da estrada, que permitiu estimar as perdas de solo associadas a diferentes tensões cisalhantes. Aos resultados obtidos em cada teste foi ajustado um modelo de regressão linear simples e, posteriormente, se aplicou a técnica de teste de identidade de modelos, a fim de obter um valor representativo destes índices para o local de estudo, além de obter o intervalo de confiança associado à erodibilidade com um nível de confiança de 95%. O valor de erodibilidade determinado para o horizonte B, foi de 0,0044 g cm-2 min-1 Pa-1, sendo a ele associado um intervalo de confiança com 95% de probabilidade de 0,0035 a 0,0053 g cm-2 min-1 Pa-1. A tensão crítica de cisalhamento determinada para este horizonte foi de 7,61 Pa. Para o horizonte C o valor de erodibilidade determinado foi de 0,0347 g cm-2 min-1 Pa-1, sendo a ele associado um intervalo de confiança com 95% de probabilidade de 0,0288 a 0,0406 g cm-2 min-1 Pa-1. A tensão crítica de cisalhamento determinada para este horizonte foi de 8,16 Pa.
Menaa, Merouane. "Performance of surface structures subjected to subsurface soil erosion." Mémoire, École de technologie supérieure, 2008. http://espace.etsmtl.ca/148/1/MENAA_Merouane.pdf.
Full textBao, Ruotian. "Effect of Microbial Induced Carbonate Precipitation on Surface Erosion." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1498471342771954.
Full textFilho, Edison Aparecido Mome. "Quantitative parameterization of soil surface structure with increasing rainfall volumes." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-30092016-095436/.
Full textO estudo da estrutura do solo permite inferências sobre seu comportamento. Parâmetros quantitativos são comumente utilizados na avaliação da estrutura e os multifractais ainda são subutilizados na ciência do solo. Alguns estudos mostraram relação entre parâmetros multifractais com a diminuição da rugosidade superficial do solo devido à chuva e a heterogeneidade do sistema poroso. No entanto, uma assinatura multifractal relacionada a um comportamento específico do solo ainda não está estabelecida. Portanto, os objetivos desta pesquisa foram: (i) relacionar parâmetros multifractais com mudanças na estrutura do solo por meio da análise de mapas de rugosidade superficial e de imagens 2D provenientes de blocos impregnados de solo; e (ii) utilizar estes parâmetros para identificar as etapas de degradação do solo devido ao selamento e encrostamento superficial. Um experimento com chuva simulada com intensidade de 120 mm h-1 foi montado em uma Nitossolo Vermelho eutroférrico argiloso em parcelas quadruplas onde aplicou-se volumes de 40, 80 e 120 mm, mais um controle sem-chuva. A evolução da rugosidade superficial foi avaliada em três escalas: um rugosímetro de campo (MRM) reuniu leituras numa grade fixa (10 x 10 mm, 640000 mm²); um escâner com triangulação de lasers em multilinhas (MLT) foi usado em laboratório, sobre blocos de solo, criando uma grade aleatório (0,5 mm de resolução, 5625 mm²); um tomógrafo de raios-X (XRT) reuniu leituras de um bloco de solo em uma grade fixa (0,074 x 0,074 mm, de 900 mm²). Para a análise micromorfométrica, amostras de solo indeformado (0,12 x 0,07 x 0,05 m) foram impregnadas, cortadas em blocos, polidas e subdivididas em três camadas (0 a 10 mm, 20 a 30 mm e de 40 a 50 mm), paralelas à superfície, tendo cinco imagens (ampliação de 10x, 156,25 μm2 pixel-1) geradas por camada. Após a segmentação, três imagens foram selecionadas por camada e o sistema poroso foi avaliado. Análises de rugosidade não mostraram diferenças (p > 0.10) entre parâmetros multifractais nas medições da escala MRM, enquanto MLT e XRT puderam ser utilizadas para modelar a degradação da rugosidade com o aumento do volume de chuva. Como essas duas ultimas escalas apresentaram resultados similares, MLT poderia substituir o uso de XRT em tais análises, devido ao seu menor custo e possibilidade de cobrir área mais vasta durante as análises. O comportamento multifractal dos poros mudou de acordo com o desenvolvimento do selamento superficial e da camada avaliada, sendo sensitivo a mudanças no grau de fragmentação (número de poros) dentro de cada classe de tamanho de poros. As dimensões de Hausdorff a esquerda do espectro (Lf(α)min, LΔf(α) and D2) tiveram relação linear com o aumento de volume de chuva para ambas medições de rugosidade superficial do solo e de área de poros. Entretanto, D2 não foi significativo (p > 0.10) entre volumes de chuva para diferenciar a porosidade próxima a superfície, embora os parâmetros D0-D1, D0-D2 e D1-D2 pudessem ser utilizados para descrever mudanças nessa camada. Conclui-se que o espectro multifractal é sensível à mudanças estruturais no solo causadas pela chuva e que pode ser utilizado na parametrização da degradação da rugosidade superficial do solo e da porosidade.
Zalewsky, Brian J. "Use of the Water Erosion Prediction Project (WEPP) Model to Predict Road Surface Erosion in Mountain Rangeland Areas." DigitalCommons@USU, 1998. https://digitalcommons.usu.edu/etd/3655.
Full textVillanueva, Evelyn. "Risk assessment of rock surface spillway erosion using parametric studies." Master's thesis, Mississippi State : Mississippi State University, 2007. http://library.msstate.edu/etd/show.asp?etd=etd-07022007-155027.
Full textMacgregor, Duncan S. "Surface seepage and sub-surface destructive processes as controls on the distribution of giant oilfields." Thesis, University of Aberdeen, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363645.
Full textBeyer, Portner Niki. "Erosion des bassins versant [sic] alpins suisses par ruissellement de surface /." [S.l.] : [s.n.], 1998. http://library.epfl.ch/theses/?nr=1815.
Full textAndermann, Christoff. "Climate, topography and erosion in the Nepal Himalayas." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2012. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-86385.
Full textCette thèse porte sur le rôle des précipitations sur l’érosion et la formation des reliefs dans l’Himalaya Népalais. J’étudie chaque étape du processus d’érosion : 1) Evaluation des bases de données de précipitations, 2) Transfert des précipitations au débit fluvial, 3) Mobilisation et transport du matériel dans le bassin versant, et enfin 4) Mécanismes d’érosion sur de longues échelles de temps. Je montre que la base de données de précipitations obtenue par interpolation de données pluviométriques est la plus performante pour la région de l\'Himalaya. Je démontre l’importance d’une composante majeure, jusqu’alors ignorée, du cycle de débit de l’Himalaya que j’identifie comme étant les aquifères de sous-sol fracturé, et j’évalue la contribution de la fonte des neiges et glaces aux rivières Himalayennes. Les taux d’érosion calculés à partir des flux de sédiments en suspension et des analyses de nucléides cosmogéniques varient de 0.1 à 4 mm/a. Les rivières au Népal sont limitées par l’apport sédimentaire alors que les versants, en tant que source de sédiments, sont limités par le transport. Enfin, je montre que l’érosion sur des milliers d’années ne dépend des précipitations mais du relief
Die vorliegende Arbeit beschäftigt sich mit der Rolle des Niederschlag bei Erosions- und Oberflächenprozessen im nepalesischen Himalaja. Ich untersuche die Abfolge der Erosionspsozesse im Himalaja: 1) Ausgehend von der Bewertung von Niederschlagsdatensätzen, 2) die Prozesse der Abflussbildung in Flüssen, 3) die Mobilisierung und Transport von Material, 4) und Erosionsraten über längere Zeiträume. Ich zeige, dass interpolierte Niederschlagsdaten die beste Qualität im Himalaya haben. Ich zeige auf, wie wichtig der bislang unberücksichtigt Grundwasserzwischenspeicher für die Abflussbildung im Himalaya ist und schätze den Anteil der Schnee-und Eisschmelze an dem Gesamtabfluss der Flüssen im Himalaja. Erosionsraten die mittels Schwebestofffracht und der Analyse kosmogener Nukluide berechnet wurden, liegen zwischen 0,1 und 4 mm pro Jahr. Der Sedimenttransport in den Flüssen in Nepal ist limitiert durch die Verfügbarkeit von transportierbarem Material, während der Transport und die Mobilisierung auf den Hängen durch die Verfügbarkeit von Wasser limitiert ist. Zudem sind die Erosionsraten über mehrere Jahrhundert nicht von der Niederschlagsverteilung abhängig sondern vom Relief
Downward, Kenneth. "Relationships between surface crusts and erosion in the Tabernas Badlands, Almeria, S.E. Spain." Thesis, University of Wolverhampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325975.
Full textKaragianna, Anthoula. "Changes in the surface chemistry of enamel exposed to acid : a surface study of caries and erosion." Thesis, University of Leeds, 2012. http://etheses.whiterose.ac.uk/3237/.
Full textNUNES, Francisco Miquéias Sousa. "Avaliação hidrossedimentologica de uma Bacia sem dados de vazão utilizando o modelo SWAT." Universidade Federal de Campina Grande, 2018. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/382.
Full textMade available in DSpace on 2018-04-13T17:34:56Z (GMT). No. of bitstreams: 1 FRANCISCO MIQUÉIAS SOUSA NUNES – DISSERTAÇÃO (PPGECA) 2018.pdf: 6096167 bytes, checksum: 209e0b24de3463f67f79ee188f4a1bc5 (MD5) Previous issue date: 2018-02
Capes
O crescimento populacional desordenado juntamente com a intensificação das atividades humanas estão acelerando as modificações dos ecossistemas naturais acarretando vários problemas ambientais, em particular , aos recursos hídricos. A necessidade da humanidade por esse recurso vem crescendo de forma rápida e incompatível com a capacidade de recuperação da natureza, causando a escassez e prejuízo na sua qualidade. Além disso, as diversas finalidades para as quais esses recursos são utilizados têm gerado um grande número de conflitos do uso e também degradação qualitativa e quantitativa dos corpos hídricos.No semiárido brasileiro, a situação de escassez hídrica compromete o desenvolvimento econômico e social da região. Assim, torna-se necessário desenvolver ferramentas adequadas para apoiar a tomada de decisão quanto ao uso dos recursos hídricos. Alterações no uso e na ocupação do solo afetam o comportamento do escoamento superficial, e a análise das tendências na vazão dos cursos d’água é importante para o planejamento do uso dos recursos hídricos e do solo. As variações no regime pluviométrico devido às mudanças climáticas também afetam a disponibilidade hídrica nas bacias hidrográficas.Este trabalho tem por objetivomodelar os processos de geração de escoamento superficial, erosão do solo e a recarga potencial subterrânea na bacia do Rio Sucuru a jusante da barragem de Sumé-PB utilizando o modelo SWAT. Foram utilizados dados de precipitação, temperatura, do período de 1994 a 2015, além de mapas de tipos de solo, uso e ocupação do solo com as mudanças observadas no período.Os parâmetros CANMAX, GWQMN, GW_REVAP, ESCO, EPCO e CN foram identificados como os mais influentes sobre o processo de geração de escoamento superficial. O valor do parâmetro GWQMN foi fixado em 2000 mm, pois nenhuma sondagem realizada na bacia indica uma profundidade do solo maior que 2,0 m. Os parâmetros CANMX, ESCO, EPCO e CN se mostraram muito influentes, pois qualquer pequena alteração para mais ou para menos, provocava uma superestimação e/ou subestimação da lâmina escoada, necessitando assim de muitas tentativas antes de obter seus valores finais. Os resultados demosntram a eficiência do modelo SWAT em quantificar e avaliar comparativamente os processos hidrossedimentologicos na região do cariri paraibano. A contribuição deste trabalho se dá pela formulação de uma metodologia para a realização de estudos hidrossedimentologicos em regiões onde não existem dados de escoamento superficial ou de produção de sedimento pela erosão.
Disorganized population growth coupled with the intensification of human activities is accelerating changes in natural ecosystems, leading to a number of environmental problems, in particular water resources. The need of mankind for this resource has been growing rapidly and incompatible with nature's capacity for recovery, causing scarcity and damage in its quality. In addition, the various purposes for which these resources are used have generated a large number of use conflicts and also qualitative and quantitative degradation of water bodies. In the Brazilian semi-arid, the situation of water scarcity compromises the economic and social development of the region. Thus, it is necessary to develop adequate tools to support the decision making regarding the use of water resources. Changes in soil use and occupation affect the behavior of surface runoff, and the analysis of trends in water flow is important for planning the use of water resources and soil. Variations in pluviometric regime due to climate change also affect water availability in river basins. This work aims to model the processes of generation of runoff, soil erosion and potential underground recharge in the Sucuru River basin downstream of the Sumé-PB dam using the SWAT model. Precipitation and temperature data were used from 1994 to 2015, as well as maps of soil types, land use and occupation with changes observed in the period. The parameters CANMAX, GWQMN, GW_REVAP, ESCO, EPCO and CN were identified as the most influential on the process of generation of surface runoff. The value of the GWQMN parameter was set at 2000 mm, since no survey conducted in the basin indicates a soil depth greater than 2.0 m. The parameters CANMX, ESCO, EPCO and CN were very influential, because any small changes for more or less, caused an overestimation and / or underestimation of the drained sheet, thus requiring many attempts before obtaining their final values. The results demonstrate the efficiency of the SWAT model in quantifying and comparing the hydrosedimentological processes in the Paraíba region. The contribution of this work is given by the formulation of a methodology for the realization of hydrosedimentological studies in regions where there is no data of surface runoff or sediment production.
Glotzbach, Christoph. "Low-temperature thermochronology from tunnel and surface samples in the Central and Western Alps." [S.l. : s.n.], 2008.
Find full textWong, Stephanie Tomita. "Computer-aided modeling of controlled release through surface erosion with and without microencapsulation." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0002206.
Full textWoodun, Jayashree Khanta. "Surface crusting of soils from the South Downs in relation to soil erosion." Thesis, University of Sussex, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270498.
Full textFinke, Manuela. "Studying food-related demineralisation of teeth with atomic force microscopy (AFM) and nanoindentation." Thesis, University of Bristol, 2001. http://hdl.handle.net/1983/8d6de76b-d940-47ad-b0f6-095f56ddf54e.
Full textAndermann, Christoff. "Climate, topography and erosion in the Nepal Himalayas." Doctoral thesis, Rennes 1, 2011. https://tubaf.qucosa.de/id/qucosa%3A22808.
Full textCette thèse porte sur le rôle des précipitations sur l’érosion et la formation des reliefs dans l’Himalaya Népalais. J’étudie chaque étape du processus d’érosion : 1) Evaluation des bases de données de précipitations, 2) Transfert des précipitations au débit fluvial, 3) Mobilisation et transport du matériel dans le bassin versant, et enfin 4) Mécanismes d’érosion sur de longues échelles de temps. Je montre que la base de données de précipitations obtenue par interpolation de données pluviométriques est la plus performante pour la région de l\'Himalaya. Je démontre l’importance d’une composante majeure, jusqu’alors ignorée, du cycle de débit de l’Himalaya que j’identifie comme étant les aquifères de sous-sol fracturé, et j’évalue la contribution de la fonte des neiges et glaces aux rivières Himalayennes. Les taux d’érosion calculés à partir des flux de sédiments en suspension et des analyses de nucléides cosmogéniques varient de 0.1 à 4 mm/a. Les rivières au Népal sont limitées par l’apport sédimentaire alors que les versants, en tant que source de sédiments, sont limités par le transport. Enfin, je montre que l’érosion sur des milliers d’années ne dépend des précipitations mais du relief.
Die vorliegende Arbeit beschäftigt sich mit der Rolle des Niederschlag bei Erosions- und Oberflächenprozessen im nepalesischen Himalaja. Ich untersuche die Abfolge der Erosionspsozesse im Himalaja: 1) Ausgehend von der Bewertung von Niederschlagsdatensätzen, 2) die Prozesse der Abflussbildung in Flüssen, 3) die Mobilisierung und Transport von Material, 4) und Erosionsraten über längere Zeiträume. Ich zeige, dass interpolierte Niederschlagsdaten die beste Qualität im Himalaya haben. Ich zeige auf, wie wichtig der bislang unberücksichtigt Grundwasserzwischenspeicher für die Abflussbildung im Himalaya ist und schätze den Anteil der Schnee-und Eisschmelze an dem Gesamtabfluss der Flüssen im Himalaja. Erosionsraten die mittels Schwebestofffracht und der Analyse kosmogener Nukluide berechnet wurden, liegen zwischen 0,1 und 4 mm pro Jahr. Der Sedimenttransport in den Flüssen in Nepal ist limitiert durch die Verfügbarkeit von transportierbarem Material, während der Transport und die Mobilisierung auf den Hängen durch die Verfügbarkeit von Wasser limitiert ist. Zudem sind die Erosionsraten über mehrere Jahrhundert nicht von der Niederschlagsverteilung abhängig sondern vom Relief.
Кирилів, Ярослав Богданович, Володимир Іванович Кирилів, Богдан Романович Ціж, and Максимів Ольга Володимирівна. "Resistance of surface nanocrystalline and ultrafine-grained structures to wear and cavitation erosion damage." Thesis, LLC «Computer-publishing, information center», Kiev, Ukraine, 2020. http://hdl.handle.net/123456789/6943.
Full textKilic, Arif Nesimi 1963. "A multi-region transient erosion model for concrete with time-dependent surface heat flux." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/290695.
Full textGarcía-Atance, Fatjo Gonzalo. "Surface response of ceramics subject to erosive wear." Thesis, Bournemouth University, 2010. http://eprints.bournemouth.ac.uk/17506/.
Full textAndermann, Cristoff. "Climate, topography and erosion in the Nepal Himalayas." Phd thesis, Université Rennes 1, 2011. http://tel.archives-ouvertes.fr/tel-00674919.
Full textKing, David. "Sonochemical analysis of the output of ultrasonic dental descalers." Thesis, University of Bath, 2010. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538276.
Full textJess, Scott. "Resolving the timing of major erosion events along the West Greenland-Baffin-Bylot continental margins." Thesis, University of Aberdeen, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=239479.
Full textBontrager, Austin. "Estimation of agricultural soil erosion and surface water quality trends in the Cheney Lake watershed." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/13182.
Full textDepartment of Agronomy
Nathan Nelson
Phosphorus and sediment runoff are the primary cause of eutrophication in Cheney Lake, the primary water source for Wichita, Kansas. Best Management Practices (BMPs) such as no-till farming practices and nutrient management can be implemented to reduce phosphorus runoff on high-risk agricultural fields. Past efforts have established BMP use in this watershed, although the effectiveness of these efforts has not been evaluated. The goals of this project were to identify any existing water quality trends in the Cheney Lake watershed, estimate the current distribution of erosion in the watershed, and evaluate the placement of BMPs with regards to field-scale erosion risk. Parametric, multi-linear regression and non-parametric, seasonal Mann-Kendall analyses were used to identify trends in the Total Suspended Solids (TSS) and Total Phosphorus (TP) of grab samples from the North Fork Ninnescah River. A Geographic Information System (GIS) model based on the Revised Universal Soil Loss Equation (RUSLE) was used to estimate watershed-scale erosion, prioritize agricultural land for BMP placement, and evaluate existing placement of BMPs within the Cheney Lake watershed. No detectible trends were identified in the water quality data due to stream variability, frequency of sampling, or absence of actual improvement in water quality. Additional sampling must be done to detect any trends in the future. BMPs were implemented on 13% of prioritized field area, and 11% of non-prioritized field area. Conservation Reserve Program (CRP) fields were placed on 14% of prioritized field area, and 5% of non-prioritized field area. No-till practices were implemented on 13% of prioritized field area, and 18% of non-prioritized field area. The top 20% eroding fields were identified given current conditions, and account for approximately 56% of the watershed-wide erosion. The GIS method has demonstrated utility in evaluating past erosion control measures for the watershed and in informing future decisions concerning BMP placement.
Alistoun, Judith Robyn. "The origin of endorheic pans on the African erosion surface North of Grahamstown, South Africa." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1011048.
Full textSantos, Julio Cesar Neves dos. "MensuraÃÃo da erosÃo do solo no semiÃrido em diferentes usos de terras e escalas espaciais." Universidade Federal do CearÃ, 2012. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=7299.
Full textA obtenÃÃo de dados de erosÃo do solo em diferentes escalas espaciais à de fundamental importÃncia, principalmente no semiÃrido do Nordeste brasileiro onde esses dados sÃo escassos. O semiÃrido brasileiro à vulnerÃvel à erosÃo hÃdrica, principalmente devido Ãs suas caracterÃsticas climÃticas, edÃficas e Ãs prÃticas de exploraÃÃes insustentÃveis, resultando no empobrecimento dos solos agrÃcolas e comprometendo a qualidade das Ãguas dos reservatÃrios superficiais (principais reservas hÃdricas da regiÃo). Nesse sentido, o presente estudo objetivou gerar dados bÃsicos de escoamento, produÃÃo de sedimento e analisar os principais processos e fontes de variaÃÃo na perda de solo em diferentes escalas espaciais em regiÃo semiÃrida, bem como os processos naturais atuantes em cada escala, e os efeitos do uso do solo na conservaÃÃo do meio. A Ãrea de estudo està localizada no semiÃrido cearense, na bacia hidrogrÃfica do Alto Jaguaribe no municÃpio de Iguatu, no Centro Sul do Estado do CearÃ. Os estudos de erosÃo e escoamento superficial foram conduzidos em trÃs nÃveis de escala: microbacias com Ãreas em torno de 1 a 3 ha, parcelas de erosÃo de 20 m2 e parcelas de 1 m2, todas sob condiÃÃes de chuvas naturais. Ao todo, foram instaladas quatro microbacias experimentais, seis parcelas de erosÃo de 20 m2 e seis parcelas de 1 m2, sob diferentes usos do solo; Caatinga nativa; Caatinga raleada; desmatamento seguido de enleiramento e cultivo de milho; e desmatamento, queima com cultivo de pastagem. O estudo ocorreu durante os anos de 2009, 2010 e 2011, com chuvas concentradas de janeiro a junho, correspondendo à estaÃÃo chuvosa da regiÃo. As coletas para quantificaÃÃo do volume escoado superficialmente e de amostras para determinaÃÃo da perda de sedimentos foram realizadas a cada evento de chuva erosiva, no acumulado de 24 horas. Ocorreram maiores coeficientes de escoamento e perdas de solo na escala de 20 m que nas escalas de 1 m e de microbacia: em relaÃÃo à escala de 1 mÂ, a parcela de 20 m provoca um aumento da velocidade de escoamento ao longo da vertente, aumentando tambÃm a capacidade de transporte; na escala de microbacia, a presenÃa de Ãreas com baixas declividades atuaram como zonas receptoras de sedimentos. Na Ãrea com cobertura de Caatinga Nativa, a presenÃa de pontos de alta erodibilidade e com solo nu, na escala de microbacia, à responsÃvel pela maior parte das perdas de solo, fato que nÃo pode ser representado na pequena escala de parcela. Jà a Ãrea que recebeu o tratamento de raleamento, apresentou na escala de microbacia menor coeficiente de escoamento superficial e menores perdas de solo em relaÃÃo à Ãrea Caatinga Nativa. O manejo de desmatamento e enleiramento dos restos vegetais e cultivo de milho, proporcionou incremento no coeficiente de escoamento superficial e nas perdas de solo em relaÃÃo ao perÃodo anterior, com cobertura de Caatinga nativa. O tratamento de desmatamento, queimada e cultivo de pastagem (Andropogon gayanus Kunt), resultou nas maiores perdas de solo e Ãgua em relaÃÃo aos demais manejos estudados.
Obtaining data of soil erosion on different spatial scales is of fundamental importance, especially in the semi-arid regions of northeastern Brazil where such data are scarce. The semi-arid region is vulnerable to water erosion, mainly due to its climatic and edaphic characteristics, and the unsustainable land use practices, which result in the impoverishment of agricultural soils, and compromise the water quality of the surface reservoirs (the main water resources of the region). The main goal of this study was generate basic data flow, sediment yield and analyze the main process and sources of variation in soil loss at different scales in semi-arid region. It analyzed the natural process that is operating in each one scale and the land use effects in the conservation of the environment. The study area is located in the semi-arid region of the state of CearÃ, in the watershed of the Upper Jaguaribe in the Iguatu County, in the south central area of the state. Studies of erosion and surface runoff were conducted on three scale levels: watersheds with areas of around 1 to 3 ha, erosion plots of 20 m2, and plots of 1 m2, all under natural-rainfall conditions. In all, four experimental watersheds were installed together with six erosion plots of 20 m2 and six plots of 1m2 with different types of land use; native Caatinga; thinned Caatinga; deforestation followed by bunching and the cultivation of corn, and deforestation, burning and the cultivation of pasture. The study was carried out from 2009 to 2011, with rainfall concentrated in the months of January to June, corresponding to the rainy season in the region. Samples to quantify the volume of surface runoff, and samples to determine sediment loss, were taken for each erosive-rain event in an accumulated period of 24 hours. There were higher runoff coefficients and soil losses on the 20 m2 scale than on the 1 m2 and watershed scales: on the scale of 1 mÂ, the plot of 20 m causes an increase in flow velocity down slopes, also increasing transport capacity; on the scale of the watershed, places with low slopes acted as receiving areas for sediment. In the area with native Caatinga vegetation, the presence of points of high erodibility and of bare soil, on the watershed scale, is responsible for most of the soil loss, a fact that is not present on the small scale of the plots. The area which was thinned out, however, presented a lower runoff coefficient and less soil-loss on the watershed scale, in relation to the area of native Caatinga. After deforestation, bunching of the plant remains, and planting of corn, an increase in the runoff coefficient and soil loss can be seen in relation to the previous period with a coverage of native Caatinga. The treatment of deforestation, burning and the cultivation of pasture (Andropogon gayanus Kunt) resulted in the greatest soil and water losses in relation to the other management strategies studied.
Lira, Daniely Lidiany Costa. "Assoreamento em densas redes de reservatÃrios: o caso da bacia hidrogrÃfica da barragem Pereira de Miranda, Ce." Universidade Federal do CearÃ, 2012. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=8835.
Full textO presente estudo tem como objetivo analisar os impactos da densa rede de reservatÃrios da bacia hidrogrÃfica do aÃude Pereira de Miranda (Pentecoste) na produÃÃo de sedimentos e capacidade de armazenamento hÃdrica do sistema. A bacia estudada localiza-se no Nordeste Brasileiro, no Estado do CearÃ, com uma Ãrea de aproximadamente 3.230 km2. Possui uma precipitaÃÃo mÃdia anual de 854 mm e evaporaÃÃo potencial mÃdia observada em tanque do tipo classe A à de 1.464 mm. O solo e a vegetaÃÃo predominante sÃo do tipo luvissolo e caatinga arbustiva aberta. Imagens de satÃlite de anos Ãmidos foram utilizadas para levantamento da aÃudagem na bacia. Foram identificadas unidades de erosÃo derivadas da sobreposiÃÃo de mapas dos parÃmetros da EquaÃÃo Universal de Perdas do Solo (EUPS), o que permitiu a estimativa da erosÃo localizada na bacia e identificaÃÃo de Ãreas potencialmente produtoras de sedimento. Um modelo simplificado foi utilizado para simular a propagaÃÃo de sedimentos pela densa rede de reservatÃrios da bacia. Para estimativa do assoreamento no reservatÃrio Pereira de Miranda, diferentes cenÃrios de estrutura do sistema foram considerados. Foi estimada uma taxa de erosÃo mÃdia na bacia de 59 t.ha-1.ano-1, sendo que 42% da Ãrea da bacia apresenta grau de erosÃo moderado. De acordo com o modelo, o assoreamento do reservatÃrio Pentecoste pode variar de 1,1 a 2,6% por dÃcada, dependendo do cenÃrio considerado. Observa-se ainda que os reservatÃrios de montante podem reter atà 58% do sedimento que chegaria ao aÃude Pereira de Miranda. Os reservatÃrios muito pequenos, com capacidade de atà 100.000 mÂ, embora representem apenas 1,83% da disponibilidade hÃdrica do sistema, sÃo capazes de reter quase 8% do total de sedimento produzido. AnÃlises de sensibilidade mostram que a capacidade de retenÃÃo de sedimentos nos reservatÃrios de montante pode variar de 20 a 58%, dependendo da estrutura do sistema quanto à existÃncia de reservatÃrios de diferentes classes de tamanho. Constata-se ainda que a taxa de reduÃÃo da capacidade de armazenamento hÃdrica do sistema em funÃÃo do assoreamento dos reservatÃrios de montante à relativamente maior do que a observada para o aÃude Pereira de Miranda, devido à retenÃÃo de sedimentos a montante.
The present study aims at analyzing the impacts of the dense reservoir network of the Pereira de Miranda catchment in its sediment yield and water storage capacity of the system. The studied area is located in the Brazilian Semiarid region, in the State of CearÃ, with an area of approximately 3230 km2. It has an average annual rainfall of 854 mm and an annual potential evaporation of 1464 mm. The predominant soil and vegetation type are luvissolo and open shrub caatinga. Satellite imageries from wet years were used to identify the reservoirs of the catchment. Erosion units were identified derived from map overlay of the parameters of the Universal Soil Loss Equation (USLE), which enables the estimation of sediment yield and the identification of areas with high sediment production. A simplified model was used to simulate the sediment routing through the dense reservoir network of the basin. For the estimation of sedimentation at the Pereira de Miranda Reservoir, different scenarios of the system structure were considered. A mean erosion rate of 59 t.ha-1.year-1 was estimated for the basin, in which 42% of the basin area presents a moderate degree of erosion. According to the model, silting of the Pereira de Miranda reservoir may vary from 1.1 to 2.6 %.decade-1, depending on the scenario considered. One may observe that upstream reservoirs are able to retain until 58% of the sediments that would reach the Pereira de Miranda reservoir. The very small reservoirs, with storage capacity below 100,000 mÂ, are able to retain almost 8% of the generated sediments, although they represent just 1.83% of the system water storage capacity. Sensitivity analysis shows that the sediment retention capacity of the upstream reservoirs may vary from 20 to 58%, depending on the system structure concerning the presence of upstream reservoirs from different size classes. One may still conclude that the reduction rate of water storage capacity at the system as a function of reservoir siltation is relatively larger then that observed for the Pereira de Miranda reservoir, due to the upstream sediment retention.
Mounirou, Lawani A. "Etude du ruissellement et de l’érosion à différentes échelles spatiales sur le bassin versant de Tougou en zone sahélienne du Burkina Faso : quantification et transposition des données." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20039/document.
Full textThe spatio-temporal variability of runoff and erosion is not new fact. Their characteristics are generally estimated with a reasonable margin on plots of a few tens of square meters. With the increase of the surface, the heterogeneity of environment increases which induces a scale effect. The passage of the plot to the catchment is not totally controlled because of the complexity and variability of factors come into play. The objective of this thesis is to understand the processes of runoff and erosion in different environments and at different spatial scales, to identify the sources of variation, and to develop a methodology for implementation of the results of field scale to the basin outlet. To this end, a network of eighteen plots of different sizes, two hydrological units were used to quantify runoff and soil loss on the main surface features Watershed Tougou.The results obtained on micro-plots of 1 m², plots of 50 and 150 m², hydrologic units of 6 and 34 ha and the catchment area of 37 km², show that, both in cultivated soils and on bare soils, the runoff excess decreases as the area increases, for the same rain and prior comparable humidity conditions of the soil. This phenomenon of the scale effect of the area on runoff is known to hydrologists who still face the challenge of extrapolating results obtained on small areas to larger areas. Our results show that the scale effect observed on the runoff is mainly due to the spatial heterogeneity of soils (hydraulic properties, microrelief) and its variability (state of the variables) and that temporal dynamics of the intensity of rain just amplifies it. The results obtained in tests of transposition can maintain with reason that a better extrapolation of data from the field scale across the pond comes from the consideration of the issues of hydrologic connectivity.Ultimately, this study highlights the value of measurements of runoff on homogeneous units in terms of land use that may represent a heterogeneous mosaic of homogeneous areas. The location on the watershed and the rate of connectivity of the hydrologic units within which the dominant processes of runoff occur can allow approach the solution of the problem of scale transfer
Kuhnert, Matthias. "Quantifizierung von Oberflächenabfluss und Erosion auf Böden mit hydrophoben Eigenschaften." Phd thesis, Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2009/3287/.
Full textThe objective of the thesis is the investigation of water repellent soil conditions and their consequences on surface runoff and erosion by water on different scales. The test site is a lignite mining area situated in Welzow Süd (south east Germany). The processes are to investigate on three different scales, starting with a plot scale (1 m²), then a hill slope scale (300 m²) and, finally, with a small catchment area (4 ha). The level of water repellency was quantified by both direct (contact angle) and indirect measurement (persistence of the soil). The results show seasonal differences with hydrophilic soil conditions during winter and water repellent reactions during summer. For this change in soil conditions, the soil water content is pronounced in literature to be the most important factor. On the test site, the soil water content changed instead as a consequence of the thawing of the soil which affects the hydrophilic conditions of the soil itself. The spatial differences of the soil water content are related to rill and channel areas (hydrophillic) and to knoll areas (water repellent). Both the spatial as well as the temporal variation of the soil conditions affect surface runoff which is investigated as a runoff coefficient (RC: ratio of amount of surface runoff to amount of precipitation). The RC shows higher values on soil with water repellent conditions (RC=0.8) in comparison with the values on hydrophilic soils (RC=0.2). The hydrophilic conditions predominate in areas with different substrates and during the winter. Observations on different scales show a decreasing RC as the size of the area increases (RC = 0.8 on the plot scale, RC = 0.5 on the hill slope scale and RC = 0.2 for the entire catchment area). The reasons for this are the hydrophilic rill in the hill slope area and the hydrophilic substrate in the entire catchment area. The measurement of erosion, based on different methods, some of them just newly developed, quantifies in a good resolution sediment transport spatially as well as temporally. The central part of one of the newly developed approaches is a balance which quantifies an event based sediment output. This approach is coupled with a tipping bucket to measure surface runoff. The system has been developed for coarse textured areas with little amounts of sand and silt. Additionally, two laser systems are used to detect changes in the soil surface over the spatial distribution. The first method contains a laser which measures only a single point and has to be moved in a fixed apparatus above the soil surface in a well defined raster. The areas of sediment abrasion and the detachment areas are restricted by interpolation of the measurement results. This method enables measurements on large areas (16 m² in this project), but tends to result in a high level of errors in the transition zone between rill and interrill. The second laser system covered an area of 1 m² in high resolution. To construct a three-dimensional picture, four different pictures have to be taken from four different directions. This defines the abrasion and detachment areas in a very detailed manner, but the method is very time-consuming and covers only a small area. In addition, measurements on the plots collected the amount of sediment output on a small scale. These results show, corresponding to the water repellent soil conditions, high rates of sediment output during summer, but low rates during winter season. The results show also the dominance of rill erosion in comparison with interrill erosion during high intensity rainfall events (>25 mm/h during one interval of ten minutes). On the contrary, interrill erosion becomes more important during low intensity rainfall events (<20 mm/h during at one interval of ten minutes). At least a 9 mm amount of precipitation with a minimum intensity of 3.6 mm/h is necessary to provoke erosion on this test site. Based on the measurement results regression empirical equations were developed to quantify surface runoff and sediment output. While, surface runoff correlates well with the amount of precipitation (r² = 0,9), sediment output shows little correlation to the amount and intensity of the precipitation (r² = 0,7). In summary, the thesis described effects of water repellent soil conditions on surface runoff and erosion on different scales. The effects on the smaller scales especially are of high interest to hydrological processes.
Albright, Amy N. "An Analysis of Slope Erosion and Surface Changes on Off-Road Vehicle Trails in Southeastern Ohio." Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1276715617.
Full textDevauchelle, Olivier. "Ecoulements de surface et érosion." Paris 6, 2007. https://hal.archives-ouvertes.fr/tel-01499527.
Full textCasas-Apayco, Leslie, Vanessa Manzini Dreibi, Ana Carolina Hipólito, Márcia Sirlene Zardin Graeff, Daniela Rios, Ana Carolina Magalhaes, Marília Afonso Rabelo Buzalaf, and Linda Wang. "Erosive cola-based drinks affect the bonding to enamel surface: an in vitro study." Faculdade De Odontologia De Bauru - USP, 2014. http://hdl.handle.net/10757/324186.
Full textThis study was supported in part by grants given by the São Paulo Research Foundation (FAPESP), Process no. 2009/14986-0, and the National Council for Scientific and Technological Development (CNPq), Process no. 480038/2007-4. In Addition, this study was performed by V.D.M. and A.C.H. as fulfillment of their graduation research, which was supported by FAPESP (Processes no. 2009/01376-9 and 2009/01377-5, respectively). The authors are also grateful to Oral B and SDI, which donated the materials used in the study.
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