Time of soil water thermodynamic equilibrium during retention curve establishment using gamma-ray beam attenuation

• Autorzy: Pires L. , Bacchi O. , Reichardt K.
• Języki publikacji: EN

Abstrakty

EN

The soil water retention curve (SWRC) represents a fundamental part of the characterization of the soil hydraulic properties. The establishment of SWRC is usually time-consuming and presents several problems such as the difficulty of a correct judgment of the time of equilibrium. This work presents a new methodology that involves gammaray beam attenuation technique associated with the traditional pressure chambers, having as objective the more precise judgment of the time to attain equilibrium. The gamma-ray source used has an activity of 3.7 GBq consisting of 241Am, with peak energy of 59.54 keV. For the determination of retention curves using the gamma-ray attenuation technique, an acrylic pressure chamber was projected and constructed to be positioned between the source and detector with the gamma-ray beam crossing the center of the chamber and the soil sample during water extraction. The proposed technique allowed, through a specifically elaborated software for data acquisition, to evaluate with precision the exact instant of the equilibrium and, consequently, to obtain the right moment to change the chamber pressure to a new desired level, leading to a reduction of the time required for the whole retention curve determination. The results obtained show that the gamma-ray attenuation technique can be very useful as an auxiliary tool to evaluate SWRC, utilizing the Richards chamber.

Słowa kluczowe

EN

gamma-ray attenuation; time of equilibrium; pressure chamber; soil water retention curve

• Wydawca: Institute of Nuclear Chemistry and Technology
• Czasopismo: Nukleonika
• Rocznik: 2005
• Tom: Vol. 50, nr 4
• Strony: 173--177
• Opis fizyczny: Bibliogr. 19 poz., rys.

Twórcy

autor

Pires L.

• Center for Nuclear Energy in Agriculture, The University of Săo Paulo, C. P. 96, C. E. P. 13.400-970, Piracicaba, SP, Brazil, Tel.: [phone] ext. 4712, Fax: [phone]

autor

Bacchi O.

• Center for Nuclear Energy in Agriculture, The University of Săo Paulo, C. P. 96, C. E. P. 13.400-970, Piracicaba, SP, Brazil, Tel.: [phone] ext. 4712, Fax: [phone]

autor

Reichardt K.

• Center for Nuclear Energy in Agriculture, The University of Săo Paulo, C. P. 96, C. E. P. 13.400-970, Piracicaba, SP, Brazil, Tel.: [phone] ext. 4712, Fax: [phone]

Bibliografia

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