TY - JOUR
T1 - Viscosity of liquid alloys
T2 - Generalization of Andrade's equation
AU - Singh, Ram Nadan
AU - Sommer, Ferdinand
N1 - Funding Information:
The results show that surface soil moisture can be accurately estimated from RADARSAT data under certain field conditions. Although the results are encouraging, they do not yet meet operational accuracy requirements. To develop the methodology further for operational use, there is a need to address the influence of the other target parameters (surface roughness and vegetation/stubble effects) on the surface soil moisture estimation. It is expected that polarimetric and/or multipolarization data from the future ENVISAT and RADARSAT-2 SAR satellites will help solve this problem by using polarization response to increase information content in a similar fashion to spectral response when using optical data. For example, the cross-polarization ratio is expected to be less sensitive to surface roughness variability, while the co-polarization ratio will help to define the vegetation type and structure. The judicious utilization of ancillary data and modelling approaches also provides additional input for estimating surface soil moisture. However, this is another limiting factor to operational implementation, as the need for site specific information increases the "cost". This application is being further investigated through a University Program being supported by the GlobeSAR-2 Program with the Institut National de la Recherche Scientifique (INRS-EAU). In this collaborative project, the hydrological model HYDROTEL (Fortin et al., 1994; Fortin et al., 2000) is being used for mapping the soil moisture in conjunction with RADARSAT images. This study demonstrated the usefulness of RADARSAT data for estimating surface soil moisture in agricultural fields. Varying roughness and vegetation conditions weaken the relationship between radar backscatter and soil moisture estimation and must be taken into account when analyzing the data. The flexible viewing geometry of RADARSAT and the supporting ground infrastructure for the data ordering, capture, and delivery allow adequate coverage opportunities and reasonable timeliness in the data delivery. The resolution is also adequate for field scale delineation and in some cases within-field variability determination. Our results suggest the potential of using RADARSAT data for estimating surface soil moisture as one input to a distributed hydrological model. Complementary soil, meteorological, and site-specific information (slope, aspect, etc.) will also be needed for the model to be effective. This information would then be of value to hydrologists and agronomists in Argentina as well as to the producers who would be able to better plan seeding, fertilization, irrigation, harvest and other management decisions.
PY - 2012/9
Y1 - 2012/9
N2 - The Andrade relation for the viscosity of liquid metals has been reformulated in terms of the Debye temperature for liquid metals. This semi-empirical relation has been extended to obtain a relation to calculate the composition and temperature dependence of the viscosity of liquid alloys using parameters which can be determined experimentally. The important inputs are the enthalpy of formation, DH, and the excess volume of mixing, DX. The composition dependence of the viscosity and its deviation from linear behavior could be positive or negative depending on the sign and magnitude of DH and DX. Several limiting cases of the semi-empirical relation for the viscosity of liquid alloys are compared and discussed. The results of the semi-empirical relation for viscosity isotherms for binary and ternary liquid alloys are mostly in reasonable agreement with available experimental results.
AB - The Andrade relation for the viscosity of liquid metals has been reformulated in terms of the Debye temperature for liquid metals. This semi-empirical relation has been extended to obtain a relation to calculate the composition and temperature dependence of the viscosity of liquid alloys using parameters which can be determined experimentally. The important inputs are the enthalpy of formation, DH, and the excess volume of mixing, DX. The composition dependence of the viscosity and its deviation from linear behavior could be positive or negative depending on the sign and magnitude of DH and DX. Several limiting cases of the semi-empirical relation for the viscosity of liquid alloys are compared and discussed. The results of the semi-empirical relation for viscosity isotherms for binary and ternary liquid alloys are mostly in reasonable agreement with available experimental results.
KW - Liquid alloys
KW - Semi-empirical relation
KW - Temperature and composition dependence
KW - Viscosity
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U2 - 10.1007/s00706-012-0728-2
DO - 10.1007/s00706-012-0728-2
M3 - Article
AN - SCOPUS:84867153725
SN - 0026-9247
VL - 143
SP - 1235
EP - 1242
JO - Monatshefte fur Chemie
JF - Monatshefte fur Chemie
IS - 9
ER -