Made available in DSpace on 2014-06-11T19:26:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2000-04Bitstream added on 2014-06-13T19:14:05Z : No. of bitstreams: 1 leitejunior_jb_me_botfca.pdf: 548112 bytes, checksum: 3c54996aed140271001523e8eeadb99f (MD5) / Com o objetivo de encontrar uma solução para a salinização dos solos sob cultivo protegido que possibilite reduzir sua salinidade com a contínua utilização das estufas, foi realizado um experimento na Fazenda Experimental São Manuel, em São Manuel, pertencente a Faculdade de Ciências Agronômicas - UNESP/ Campus de Botucatu.O experimento foi conduzido nos meses de outubro e novembro de 1999, num solo denominado Latossolo Vermelho Amarelo textura média, e consistiu na simulação de adubação excessiva, através da adição de 645 g.m-2 de cloreto de potássio (KCl) e 51 g.m-2 de fosfato monoâmonico (MAP). A cultura utilizada foi a alface americana cultivar Tainá, transplantada no espaçamento de 35 x 35 cm e irrigada através de gotejamento. O experimento consistiu num fatorial 23, cujos fatores foram (nos níveis presença e ausência): pré-lavagem do solo antes do transplantio com uma lâmina de 101,89 mm; cobertura plástica preta do solo (mulching) e lixiviação a cada irrigação (com fração de 50% e irrigação diária, até 20 dias após o transplantio (DAT), e 30% até o final com irrigação a cada 2 dias.Com base nos resultados, pode-se concluir que a pré-lavagem não foi eficiente na redução de íons do solo, somente reduziu o pH havendo uma interação significativa entre a presença deste com a presença do mulching para os íons H++Al3+ no aumento da concentração desse, mas teve efeito na redução da condutividade elétrica na profundidade de 20cm aos 2 DAT e aos 14 DAT interagindo com a lixiviação.O mulching de cor preta foi eficiente na redução dos níveis dos elementos K, Ca e Mg a 20 cm de profundidade refletindo nas características químicas soma de bases, capacidade de troca catiônica e saturação de bases, mas reduziu o diâmetro das cabeças da alface americana. Apesar da condutividade elétrica não ter diferido significativamente, ele reduziu os sais na superfície dos canteiros...(Resumo co / With the objective of finding a solution for the salinization of the soils under protected cultivation and that it facilitates to reduce its salinity with the continuous use of the stoves, an experiment was accomplished in Experimental Farm São Manuel, in São Manuel, belonging the Faculdade de Ciências Agronômicas - UNESP/ Campus of Botucatu. The experiment was driven the months of October and November of 1999, in a soil denominated latosoil red yellow medium texture, and it consisted of the simulation of excessive fertilization through the addition of 645 g.m-2 of potassium chloride (KCl) and 51 g.m-2 of phosphate monoammmonic (MAP). THE used culture went to American lettuce to cultivate Tainá , transplanted in the spacing of 35 x 35 cm and irrigated through leak. The experiment consisted of the combination of 3 factors in 2 levels, whose factors were: pré-wash with a sheet of 101,89 mm; black plastic covering of the soil (mulching) and leaching to each irrigation (with fraction of 50% and daily irrigation, until 20 days after the transplant DAT , and 30% until the end with irrigation to every 2 days), in the levels with and without presence of the factor. With base in the results, it can be concluded that the pré-wash was not efficient in the reduction of ion of the soil, it only reduced the pH having a significant interaction among the presence of this with the presence of the mulching for the ion H++Al3+ in the increase of the concentration of that, but it had effect in the reduction of the electric conductivity in the depth of 20cm to 2 DAT and to 14 DAT combining the effects with the leaching...(Complete abstract, access undermentioned electronic address).

Orientador: Antônio de Pádua Sousa / Resumo: Com o objetivo de encontrar uma solução para a salinização dos solos sob cultivo protegido que possibilite reduzir sua salinidade com a contínua utilização das estufas, foi realizado um experimento na Fazenda Experimental "São Manuel", em São Manuel, pertencente a Faculdade de Ciências Agronômicas - UNESP/ Campus de Botucatu.O experimento foi conduzido nos meses de outubro e novembro de 1999, num solo denominado Latossolo Vermelho Amarelo textura média, e consistiu na simulação de adubação excessiva, através da adição de 645 g.m-2 de cloreto de potássio (KCl) e 51 g.m-2 de fosfato monoâmonico (MAP). A cultura utilizada foi a alface americana cultivar "Tainá", transplantada no espaçamento de 35 x 35 cm e irrigada através de gotejamento. O experimento consistiu num fatorial 23, cujos fatores foram (nos níveis presença e ausência): pré-lavagem do solo antes do transplantio com uma lâmina de 101,89 mm; cobertura plástica preta do solo ("mulching") e lixiviação a cada irrigação (com fração de 50% e irrigação diária, até 20 dias após o transplantio (DAT), e 30% até o final com irrigação a cada 2 dias.Com base nos resultados, pode-se concluir que a pré-lavagem não foi eficiente na redução de íons do solo, somente reduziu o pH havendo uma interação significativa entre a presença deste com a presença do "mulching" para os íons H++Al3+ no aumento da concentração desse, mas teve efeito na redução da condutividade elétrica na profundidade de 20cm aos 2 DAT e aos 14 DAT interagindo com a lixiviação.O "mulching" de cor preta foi eficiente na redução dos níveis dos elementos K, Ca e Mg a 20 cm de profundidade refletindo nas características químicas soma de bases, capacidade de troca catiônica e saturação de bases, mas reduziu o diâmetro das cabeças da alface americana. Apesar da condutividade elétrica não ter diferido significativamente, ele reduziu os sais na superfície dos canteiros...(Resumo co / Abstract: With the objective of finding a solution for the salinization of the soils under protected cultivation and that it facilitates to reduce its salinity with the continuous use of the stoves, an experiment was accomplished in Experimental Farm "São Manuel", in São Manuel, belonging the Faculdade de Ciências Agronômicas - UNESP/ Campus of Botucatu. The experiment was driven the months of October and November of 1999, in a soil denominated latosoil red yellow medium texture, and it consisted of the simulation of excessive fertilization through the addition of 645 g.m-2 of potassium chloride (KCl) and 51 g.m-2 of phosphate monoammmonic (MAP). THE used culture went to American lettuce to cultivate " Tainá ", transplanted in the spacing of 35 x 35 cm and irrigated through leak. The experiment consisted of the combination of 3 factors in 2 levels, whose factors were: pré-wash with a sheet of 101,89 mm; black plastic covering of the soil (mulching) and leaching to each irrigation (with fraction of 50% and daily irrigation, until 20 days after the transplant " DAT ", and 30% until the end with irrigation to every 2 days), in the levels with and without presence of the factor. With base in the results, it can be concluded that the pré-wash was not efficient in the reduction of ion of the soil, it only reduced the pH having a significant interaction among the presence of this with the presence of the mulching for the ion H++Al3+ in the increase of the concentration of that, but it had effect in the reduction of the electric conductivity in the depth of 20cm to 2 DAT and to 14 DAT combining the effects with the leaching...(Complete abstract, access undermentioned electronic address). / Mestre

Made available in DSpace on 2015-05-08T14:59:32Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 804392 bytes, checksum: c59b269fae4711524aa78e01083fde7e (MD5) Previous issue date: 2002-02-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work presents a theoretical study of the thermal balance of a multiple effect desalting (MED) unit type horizontal tube with thin film, used as an alternative source of potable water. The operations principles of different desalting processes are presented and a thermal balance over a MED unit with 18 effects is done. The obtained results of distilled production and specific energy consummation are also presented for different operating conditions. In this work are show results about the influences of salt water heating conditions and the salt water volumetric flow. The results show a salt water conversion as desalting water between 22 and 30 %. / Este trabalho apresenta um estudo teórico do balanço térmico em um dessalinizador múltiplo efeito do tipo tubo horizontal com filme fino, usado como fonte alternativa de água potável. São apresentados os princípios de funcionamento de diferentes processos de dessalinização, sendo efetuado o balanço térmico de uma instalação de dessalinização MED de 18 efeitos. Os resultados obtidos, em termos de produção de destilado e de consumo de energia específica, também são apresentados para diferentes condições de operação. Apresenta-se ainda, resultados quanto à influência das condições de fornecimento de calor à água a ser dessalinizada, bem como a influência da sua vazão de abastecimento. Os resultados obtidos indicam uma conversão de água salobra em água dessalinizada da ordem de 22 a 30 %.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / This dissertation presents the experimental result of a system to absorb solar energy to heat up a desalination tower with heat recovery mechanism and a change made in the heated water distribution at the heat storage tank. The system to absorb solar energy consists of solar thermal flat plate collectors for high temperatures and it responsible for the conversion of solar radiation in thermal energy to heat up the water to be desalinated. The change made in the storage tank consists of the installation of a stainless steel pipe with holes equally spaced and arrangement to allow a better distribution of the hot water from the solar collectors in the heat storage tank. The desalination unit has two components: two high temperatures solar collectors and a desalination tower with six stages. In its operation, water is heated in the solar collectors and moves by natural convection to the storage tank, to the bottom of the tower. In the tank, the water transfers heat to the salty water in the first stage of the tower. This heated water transfer heat by evaporation, convection and radiation to the second stage and part of its energy is lost to the ambient. The condensed vapor on the walls of the stages flows down by gravity to be collected in a reservoir installed under the desalination tower. The heat received by the second stage is used to heat up the ater in this stage and the process is repeated in all stages. The performance of the desalination unit was satisfactory. The temperature in the storage tank reached values near 85ÂC and the water temperatures at the outlet of the solar collector were near 100ÂC. The daily production was 31 liters of desalinated water and the GOR-value (gain output ratio) was 1,54

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2012. / Recently much research and development has been done into the creation of desalination systems in South Africa, with particular emphasis on the commercialisation of desalination plants that serve local communities. This has been successful - there are currently plants running at Bitlerfontien, Bushmans River Mouth and Robben Island - although membrane fouling and scaling remains a problem associated with membrane desalination, as it does worldwide The aim of this study was to Investigate the performance of different type of antiscalants on artificially scaled membranes which we prepared inside the lab as well as on scaled membranes which were used in pilot plant. We used two type of anti-sealants in our research: Vitec 3000 and Zinc ions. The effects of these anti-sealants on the membrane were determind and the RO performances of the treated and untreated membrane compared. A suitable autopsy procedure was established and was then used to autopsy the XLE 4040 membranes. The autopsied membranes were characterized by scanning electron microscopy (SEM) and optical microscopy (OM). The SEM and OM results clearly showed that scaling had taken place: deposits were observed for both the shell and core samples, which were not present in the images of the untreated membrane, especially when looking at high SEM images magnification. Results also showed that the anti-sealants reduced the fouling and scaling on the membrane surface. As a result, the membrane rejection improved. Rejection and flux results indicated that commercial anti-sealant was more effective in preventing scaling than the Zinc ions. For Vitec anti-sealant case, the flux was in steady state at 36.8 Imh (5% less) after 5 hours compared to around 35 Imh (8% less) for zinc ions case. In addition; SEM images showed that less deposited particles are formed when the membrane was treated with commercial anti-sealant.