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Gamma-ray beam attenuation as an auxiliary technique for the evaluation of the soil water retention curve
Provedor de dados: 63
Autores: BACCHI,O.O.S.; REICHARDT,K.; OLIVEIRA,J.C.M.; NIELSEN,D.R.
The soil water retention curve is fundamental for the hydraulic characterization of a soil and has many applications in agricultural research as well as in practical agriculture. A new procedure for soil moisture and soil bulk density evaluation inside closed pressure chambers through gamma-ray beam attenuation is presented. The proposed procedure presents several advantages in relation to the traditional process: avoids the need of continuous sample manipulation; minimizes the problem of hysteresis; allows a more precise evaluation of soil moisture by taking into account changes of soil bulk density due to swelling or shrinking on addition or removal of water; allows frequent evaluation of soil moisture without the need of opening the pressure chamber;...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Gamma attenuation; Gamma radiation; Soil water retention.
Ano: 1998
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161998000300019

EXACT EQUATIONS FOR SOIL PARTICLE-SIZE ANALYSIS BY GAMMA-RAY ATTENUATION
Provedor de dados: 63
Autores: Elias,Elimoel Abraão; Bacchi,Osny Oliveira Santos; Reichardt,Klaus.
Soil particle-size analysis by gamma-ray attenuation was first suggested in 1992 and improved in 1997 by diminishing the measurement time and adapting it for automation. It is here demonstrated that when the mass attenuation coefficient &lt;FONT FACE="Symbol"&gt;m&lt;/font&gt;w and the density Dw are replaced by &lt;FONT FACE="Symbol"&gt;m&lt;/font&gt;s and Ds (where the subscripts w and s stand for water and solution) in the approximate equations used to estimate the concentration of suspended particles, they become exact. The demonstration is based by treating the dispersant and water solution as one single medium, instead of treating them as two media. In this way, six variables are reduced to only three. Physical considerations suggest that the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Granulometry; Soil mechanical analysis; Soil texture; Gamma attenuation.
Ano: 1999
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161999000100014