Thesis (M.Sc.)(Soil Science)--University of Pretoria, 2006. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

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Thesis (Mino). / Bibliography: leaves 131-136.

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The aim of this study was to provide some information about the hydraulic performance of mattresses protecting slopes of low head hydraulic structures. The flow resistance as well as stability of slope were investigated. The experimental programme was conducted in the Chilworth Hydraulics Laboratory, Department of Civil Engineering. Two models were constructed and tested. The inpermeable model (first) had a slope of 1:7 (V;H) with mattress dimensions of 320x350mm and a height of 40mm. The permeable model (second) was built with the same slope except that the mattresses were protecting a sand core. The flow resistance of the mattresses was studied which included Manning's roughness coefficient, Chezy's resistance factor and Darcy-Weisbach friction factor. Velocity distribution above the mattresses was evaluated and found well describing the flow. The stability of the mattresses and their ability to resist failure when exposed to higher discharges were also examined and found stable under the discharges tried. Detailed measurement of pressures were conducted in the permeable model in order to study their effects on the stability of the mattresses; such as; pressure distribution above the mattresses, uplift pressures and seepage forces. Shear stresses due to seepage forces were found very small and could be neglected. Comparison with the results of smooth board simulating a reinforced concrete structure, favours the mattresses as a means to control erosion and dissipate energy efficiently. Measures were suggested in terms of installation to reduce the drag and uplift forces. A design procedure for a slope protected by mattresses was set up and followed by a numerical example implementing the results obtained in this study.

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Made available in DSpace on 2014-06-11T19:26:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-28Bitstream added on 2014-06-13T18:30:33Z : No. of bitstreams: 1 miorini_tjj_me_botfca.pdf: 709367 bytes, checksum: 5563102a43669b1f6775288f0e76df0c (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Universidade Estadual Paulista (UNESP) / O feijão (Phaseolus vulgaris L.) tem grande expressão no cenário econômico e social do Brasil, pois além de ser um alimento básico da população brasileira, faz parte da renda do pequeno e médio produtor rural. A hipótese deste trabalho é que a supressão do fornecimento de água em alguma fase ou em algumas fases do desenvolvimento do feijoeiro irrigado sempre resulta em redução de produtividade de, pelo menos, 20%. O objetivo foi de analisar a influência do uso da irrigação em diferentes estádios fenológicos do feijoeiro sobre o desempenho dos componentes de produção do feijão do grupo Carioca, cultivar IAC Alvorada. O presente trabalho foi desenvolvido na Fazenda Experimental Lageado / Departamento de Engenharia Rural, da Faculdade de Ciências Agronômicas, UNESP, campus de Botucatu. O delineamento estatístico utilizado foi o de blocos ao acaso, com 16 tratamentos e oito repetições, sendo cada parcela de 2,0 m x 4,5 m (Experimento I – campo) e 32 tratamentos e 4 repetições em vasos de 9 litros (Experimento II – casa de vegetação). Os tratamentos foram baseados em diferentes épocas de aplicação de lâminas de água em períodos críticos na cultura do feijão. No Experimento I – campo, as fases críticas consideradas foram: fase vegetativa, floração, enchimento de grãos e maturação... / Bean (Phaseolus vulgaris L.) is widespread in the social and economic scene in Brazil, as well as being a staple of Brazilian population, helps small and medium-income farmers. The hypothesis is that if the water supply is suppressed in just one of the five development stages or in some phases of development of irrigated beans, it can result in reduction productivity of, at least, 20%, allowing water economy. The objective of this study was to compare the performance of bean Carioca group IAC Alvorada yield components, with irrigation suppression in each of the phenological phases and no irrigation and irrigated in all stages. The study was conducted at Agronomical Sciences College, UNESP, Botucatu, SP, Brazil. The statistical design was the randomized block with sixteen treatments and eight replications, each plot was 2.0m X 4.5m (Experiment I – Field) and thirty-two treatments and four replications in vase of 9l (Experiment II – Greenhouse). Treatments were based on different application times water depth at critical periods in the bean crop. In Experiment I – Field, the critical phases were: vegetative stage, flowering, grain filling and maturation. In Experiment II – Greenhouse, the critical phases were: VI (V1 – V3), VII (V4 – flowering), flowering, pod formation and filling grain. Irrigations were performed to increase the water soil content to the field capacity using a class A Pan (Experiment I) and using tensiometers (Experiment II). Variables evaluated were: average number of pods per plant, pods of average size, average number of grains per pods, weight of 100 grains and productivity. Data were analyzed using SAS statistical program, subjected to analysis of variance and “t” test at 5% probability, as well as study of orthogonal contrasts. In Experiment I – Field, the yield components were higher affected when it occurred irrigation’s... (Complete abstract click electroni

Made available in DSpace on 2014-06-11T19:26:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-03-19Bitstream added on 2014-06-13T18:55:11Z : No. of bitstreams: 1 lopes_tc_me_botfca.pdf: 369263 bytes, checksum: 7a2e501b9cbc772082621a138b4fdf38 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Espécies vegetais apresentam diferentes comportamentos quando submetidas a determinados níveis de salinidade, podendo apresentar diminuição no seu crescimento e produtividade. Estudos realizados com NaCl apresentam resultados que demonstram efeitos nocivos às características morfofisiológicas de plantas. No Brasil existem poucos estudos que relatam o comportamento de espécies do gênero eucalipto sob o efeito da presença de sais no solo. Para recuperação e utilização das áreas que contêm alta concentração de sais no solo é necessário que se conheça o comportamento do material desejado quando submetido a diferentes níveis de condutância elétrica e tipos de sais presentes. A água, quando presente no solo em quantidade suficiente ao adequado desenvolvimento dos vegetais, pode evitar problemas como a toxicidade causada por íons como o Na+ e o Cl-, uma vez que participa de praticamente todos os processos bioquímicos e fisiológicos da mesma, atuando como principal constituinte dos tecidos, solvente para sais e nutrientes, reagente em processos metabólicos, mantenedora da turgescência e moderadora térmica dos tecidos. Deste modo foi avaliada, nesta pesquisa, a influência dos níveis de salinidade de solo sobre o desenvolvimento inicial pós-plantio de mudas de Eucalyptus platyphylla. O teste experimental foi conduzido em casa de vegetação, no Departamento de Engenharia Rural, da Faculdade de Ciências Agronômicas/UNESP – Botucatu, no período de 20 de abril a 07 de junho de 2011. Para realização do estudo, foram utilizados vasos cilíndricos preenchidos com solo, contendo doses de NaCl, de modo a proporcionar os níveis e condutividade elétrica desejados: 1,41; 2,50; 4,50; 6,45 e 8,33 dS.m-1, contou ainda com duas lâminas de irrigação (- 1,5 e -0,01 MPa de potenciais mínimos... / Vegetable species present different behavior when subjected to certain levels of salinity, which may have decreased their growth and productivity. Studies of NaCl plant application present results that demonstrate harmful effects on plants. In Brazil there are few studies which report the Eucalyptus platyphylla behavior under the effect of salts in the soil. In order to recovery of areas containing high salt concentration in soil it is necessary to know plant behavior when subjected to different electrical conductance levels. Water in sufficient quantity to proper development of plants can prevent problems such as toxicity caused by ions such as Na+ and Cl-. Experimental testing was conducted in a greenhouse at the Department of Rural Engineering, Faculty of Agricultural Sciences / UNESP – Botucatu, in the period April, 20 to June, 07, 2011. For accomplishment of study cylindrical pots filled with soil were utilized containing doses of NaCl to provide the following electrical conductivity levels: 1.41, 2.50, 4.50, 6.45 and 8.33 dS.m-1. Two minimum soil water potential were applied: -0.01 and -1,5 MPa. The evaluations regarding morphophysiological features were held throughout the period of conductance of work. Based on the results obtained by the Tukey test at 5% significance level the salinity levels applied did not influence significantly some of the morphophysiological parameters analyzed in this study, such as mass of... (Complete abstract click electronic access below)

Food production is a growing industry in Arizona making safe and sustainable practices for irrigating crops of the utmost importance. Harvesting materials such as knives, packing crates, plastic pallets and processing tables are constantly exposed to soil and other bacteria- laden environments presenting the risk for contamination. Irrigation pipelines are assembled using rubber gaskets to make a watertight seal. The gasket pipeline interface is a warm, moist environment that is subject to biofilm accumulation. Therefore, a long-term sanitization treatment of these materials would be greatly beneficial to the farms of Yuma, Arizona. Quaternary ammonium compounds and chlorine dioxide have proven to be sufficient household cleaning products. Our work examined the efficiency of these products as well as others in long- term sanitization of harvesting materials and irrigation systems. Treating materials with these compounds did not inhibit microbial growth or prevent biofilm accumulation in irrigation systems. The first study treated of harvesting materials (knives) with sanitization treatments. Samples were qualitatively analyzing the presence of Escherichia coli (E. coli) as an indicator bacteria and its ability to survive on the equipment after the equipment goes through three different treatments; water (as a control), QACs and bleach. The second study determined the efficacy of these treatments on packing materials such as wood, plastic and metal. Both studies found the treatment, given the contamination levels present in the study, was not an effective microbial control. The third study will quantified the presence of heterotrophic bacteria, E. coli and Salmonella as indicators of biofilm accumulation on irrigation pipeline gaskets. The same treatment methods were used for the gaskets that hold the irrigation pipelines together. The study determined that treating the gaskets did not inhibit the growth of biofilms and that pretreatment was not an effective microbial control. A field study determined that treatment residues did not affect the growth of spinach. The present research provides preliminary data to assist in the development of future studies.