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ISRN Thermodynamics
Volume 2012 (2012), Article ID 614086, 5 pages
http://dx.doi.org/10.5402/2012/614086
Research Article

On the Thermal Effusivity of Bovine Milk

Applied Physics Department (APL), Centro Brasileiro de Pesquisas Físicas (CBPF), Rua Dr. Xavier Sigaud 150, Urca, 22290-180 Rio de Janeiro, RJ, Brazil

Received 31 October 2012; Accepted 25 November 2012

Academic Editors: J. K. Brennan, C. D. Daub, H. Hirao, and P. Trens

Copyright © 2012 Daniel Acosta-Avalos and Daniel Soares Velasco. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Thermal diffusivity, conductivity, and effusivity are parameters that can be measured using photoacoustic techniques. Both thermal diffusivity and conductivity have already been measured for bovine milk. To complete its thermal characterization, this paper deals with the thermal effusivity of commercial bovine milk with a different fat content. The thermal effusivity ε obtained for skimmed, partly skimmed, and whole milks is 0.153 W cm−2 s1/2 K−1, 0.144 W cm−2 s1/2 K−1, and 0.140 W cm−2 s1/2 K−1, respectively, with the uncertainty being less than 5%. It was observed that the thermal effusivity decreases with the increase in the fat content. For the first time, it is observed that the thermal effusivity is a linear function of the logarithm of the fat content. The comparison of our results with previous results for milk from Slovakia revealed different thermal effusivity values. This might be due to regional differences in the milk composition and could be used as a criterion to identify the milk provenience.