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Wyszukujesz frazę "gamma-ray" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Time of soil water thermodynamic equilibrium during retention curve establishment using gamma-ray beam attenuation
Autorzy:
Pires, L.
Bacchi, O.
Reichardt, K.
Powiązania:
https://bibliotekanauki.pl/articles/148674.pdf
Data publikacji:
2005
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
gamma-ray attenuation
time of equilibrium
pressure chamber
soil water retention curve
Opis:
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.
Źródło:
Nukleonika; 2005, 50, 4; 173-177
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gamma-ray beam attenuation to assess the influence of soil texture on structure deformation
Autorzy:
Pires, L.
Bacchi, O.
Dias, N.
Powiązania:
https://bibliotekanauki.pl/articles/147480.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
gamma-ray attenuation
soil physical properties
soil structure deformation
soil sampling
soil porosity
Opis:
Gamma-ray beam attenuation is a non-invasive technique that permits analysis of soil porosity without disturbing the region of interest of the core sample. The technique has as additional advantage to allow measurements point by point on a millimetric scale in contrast to other methodologies that are invasive and analyze the soil properties in the bulk sample volume. Soil porosity can be used as an important parameter to quantify soil structural damages, which affect soil aeration, water movement and retention. In this study, porosities of three soils different in texture were measured at various positions in order to analyze the impact of the sampling procedure on the structure of each particular soil texture. The gamma-ray attenuation system consisted of an 241Am radioactive source having an activity of 3.7 GBq, collimated with cylindrical lead collimators of 2 mm diameter. The results obtained show the presence of dense regions near the edges of samples and that different soil textures can suffer distinct deformations at sampling.
Źródło:
Nukleonika; 2006, 51, 2; 125-129
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design, construction and performance of a pressure chamber for water retention curve determination through traditional and nuclear methods
Autorzy:
Pires, L.
Bacchi, O.
Powiązania:
https://bibliotekanauki.pl/articles/146181.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
soil water potential
gamma-ray attenuation
soil water content
soil physics
radioisotope application
Opis:
We present in this work a detailed design of a small low-pressure chamber outfitted with a ceramic porous plate for evaluating the soil water retention curve (SWRC) in the water potential range from 0 to -100 kPa. The chamber is made of acrylic and permits the use of one unique soil sample each time. The use of this chamber allows quick measurements of soil moisture using nuclear (based on gamma-ray attenuation) and conventional methods and SWRC determinations made with the designed chamber are in agreement with those obtained using a commercial low-pressure chamber. The chamber was designed especially for testing the use of the nuclear method as an auxiliary tool for SWRC determinations but it can be easily adapted for routine investigations and a practical alternative for the conventional SWRC method.
Źródło:
Nukleonika; 2006, 51, 4; 225-230
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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