Data/hora: 05/06/2024 04:43:42

Biblioteca(s): | Embrapa Instrumentação.
Data corrente: | 22/12/1999
Data da última atualização: | 03/03/2010
Autoria: | TANNUS, T. A.; PANEPUCCI, H. C.; POSADAS, D. A.; CRESTANA, S.
Afiliação: | USP-IFSC; Universidade Estadual de Ponta Grossa; EMBRAPA-CNPDIA.
Título: | Dynamic imaging approach for 3-D preferential flow within stratified soil samples.
Ano de publicação: | 1994
Fonte/Imprenta: | In: ENCONTRO NACIONAL DE FISICA DA MATERIA CONDENSADA, 17., jun. 1994, Caxambu, MG. Resumos... Sao Paulo: Sociedade Brasileira de Fisica, 1994.
Páginas: | p.296.
Idioma: | Inglês
Conteúdo: | It describes a new NMR imaging approach to investigate the dynamics of the soil "fingering" phenomenum. To study the "fingering" dynamics a fast experiment was performed to follow only the water front (no image reconstruction), constructed by curves that resembles the wetting profile in vertical slices of a soil sample. A cubic 15x15x15cm3 double-layer sand column simulates the stratified soil. Spin-echo signals with phase encoding along vertical axis (gravitational direction) were acquired, but with phase encoding gradient off, giving 16 acquisitions of 7 transverse slices in a 3 minutes experiment. After suitable treatment, the water front and the horizontal distribution at each measured time of the water infiltration was obtained. Normalizing the signal intensities to the soil column dimensions and using computational graphics resources it was possible to quantify the number of fingers and their spatial and temporal variability. The column was also imaged in a 500 Gauss NMR tomograph under conventional SE methodology. Coronal, transverse and sagittal images of the column were acquired under water steady-state flow providing three-dimensional information regarding the number of fingers, their sizes and diameters, to be compared to the dynamic images. The results to be shown elects this approach of magnetic resonance imaging as a valuable tool for non-invasive study of the dynamics of soil "fingering" and other fast changing phenomena.
Palavras-Chave: | 3-D; Dynamic imaging; NMR; Nuclear magnetic resonance; Stratified soil samples; Three-dimensional.
Thesaurus Nal: | preferential flow.
Categoria do assunto: | --
Registro original: | Embrapa Instrumentação (CNPDIA)
Exemplares: | CNPDIA - (5700-1) - UPC - SP - -- - PROCI-94.00067 -  - 1994.00067 - DIS