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| Rossi,Paulo; Miranda,Jarbas H.; Duarte,Sérgio N.. |
| Devido à grande importância em se avaliar o destino e o transporte de íons no solo, o presente trabalho teve o objetivo de obter os parâmetros de transporte do nitrato no solo, como a velocidade da água nos poros (v), o fator de retardamento (R), a dispersividade (lambda) e o coeficiente de dispersão (D), em solos de diferentes texturas e em amostras deformadas e indeformadas. O ensaio foi conduzido empregando as amostras deformadas e indeformadas oriundas de dois perfis distintos de solos, coletadas à profundidade de 0-20 cm, com aplicação de solução de nitrato de cálcio contendo 50 mg L-1 de NO3-. Após a obtenção dos parâmetros de transporte, ajustados pelo programa computacional CXTFIT, notou-se que as curvas de efluentes preparadas com solos a partir... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Dinâmica de solutos; Amostras de solo; Parâmetros de transporte. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162007000400010 |
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| Gonçalves,Adriano D. M. A.; Miranda,Jarbas H.; Rossi,Paulo; Sabadin,José F. G.; Kamogawa,Marcos Y.. |
| When doing researches on solute dynamics in porous medium, the knowledge of medium characteristics and percolating liquids, as well as of external factors is very important. An important external factor is temperature and, in this sense, our purpose was determining potassium and nitrate transport parameters for different values of temperature, in miscible displacement experiments. Evaluated parameters were retardation factor (R), diffusion/dispersion coefficient (D) and dispersivity, at ambient temperature (25 up to 28 ºC), 40 ºC and 50 ºC. Salts used were potassium nitrate and potassium chlorate, prepared in a solution made up of 5 ppm nitrate and 2.000 ppm potassium, with Red-Yellow Latosol porous medium. Temperature exhibited a positive influence upon... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Breakthrough curves; Miscible displacement; Computational modeling. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162008000300005 |
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| Hamada,Emília; Ghini,Raquel; Fernandes,Jeferson Lobato; Pedro Júnior,Mário José; Rossi,Paulo. |
| One of the main factors influencing the occurrence of plant diseases is the leaf wetness duration (LWD). However, this climatic parameter is not generally and systematically recorded at meteorological stations, and the alternative to obtain an estimate for LWD is the use of mathematical models. The objective of this study was to estimate LWD for the State of São Paulo, on the basis of the number of hours with relative humidity equal to or higher than 90%, and also plot them on a map with help of the Geographical Information System (GIS) tool. Using daily relative humidity data from ten meteorological stations of the State, for six years, adjustment equations were obtained for different LWD periods (hours day-1) (R² from 0.58 to 0.81) and of number of days... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Plant diseases; Relative humidity; Geographical Information System; Regression equation. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162008000700006 |
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| Hamada,Emília; Ghini,Raquel; Rossi,Paulo; Pedro Júnior,Mário José; Fernandes,Jeferson Lobato. |
| Viticulture in Brazil has been growing in importance in recent years. In the State of São Paulo, a significant percentage of the production is basically destined to in natura consumption and, more recently, much effort has been made by institutions to revitalize the viticulture in the State. Among fungal diseases, the downy mildew (Plasmopara viticola) is one of the main diseases affecting this crop in Brazil, with extreme damage effects on its production. The objective of this study was to estimate the incidence of the downy mildew on grape under the climatic conditions of the State of São Paulo, based on a mathematical model and using Geographical Information System - GIS tools. The study considered the months from September to April, a period in which... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Vitis spp.; Geographical Information System; Temperature; Relative humidity; Leaf wetness duration. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162008000700010 |
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