<abstract xmlns="http://www.w3.org/1999/xhtml">A microwave generator and a closed-circuit wind tunnel were used to measure the thermal diffusivity of tobacco (<italic>Nicotianatabacum</italic> L.) stems in vivo by the unsteady-state method. A simple mathematical model for heat flow, based on Fourier's heat-conduction equation and Newton's law of cooling, was used in this study. The microwave method was found to be relatively rapid as both heating and cooling of a cylindrical stem in an air stream could be completed in approximately 30 minutes for thermal-diffusivity determinations. Thermal-diffusivity value of the tobacco stems, containing 94 % moisture and a mean stem temperature of 30°C, was found to be (1.38 ± 0.06) × 10-7 m2 s-1. The coefficient of variation for the measurements did not exceed 1.4 % as determined through the analysis of cooling curves for five different air-flow rates over the stems. This study showed that the microwave technique could be effectively used to determine both accurately and reliably the thermal diffusivity of tobacco stems <italic>in vivo</italic>.</abstract>

A microwave generator and a closed-circuit wind tunnel were used to measure the thermal diffusivity of tobacco (Nicotianatabacum L.) stems in vivo by the unsteady-state method. A simple mathematical model for heat flow, based on Fourier's heat-conduction equation and Newton's law of cooling, was used in this study. The microwave method was found to be relatively rapid as both heating and cooling of a cylindrical stem in an air stream could be completed in approximately 30 minutes for thermal-diffusivity determinations. Thermal-diffusivity value of the tobacco stems, containing 94 % moisture and a mean stem temperature of 30°C, was found to be (1.38 ± 0.06) × 10-7 m2 s-1. The coefficient of variation for the measurements did not exceed 1.4 % as determined through the analysis of cooling curves for five different air-flow rates over the stems. This study showed that the microwave technique could be effectively used to determine both accurately and reliably the thermal diffusivity of tobacco stems in vivo.

A Transient Method for Determining Thermal Diffusivity of Tobacco Stems

Department of Renewable Resources, Macdonald College of McGill University, Ste. Anne de Bellevue, Quebec, Canada

Experimental Farm, Agriculture Canada, L ‘Assomption, Quebec, Canada

Contributions to Tobacco & Nicotine Research

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

{"article-title":"A Transient Method for Determining Thermal Diffusivity of Tobacco Stems"}

A microwave generator and a closed-circuit wind tunnel were used to measure the thermal diffusivity of tobacco (Nicotianatabacum L.) stems in vivo by the...

A Transient Method for Determining Thermal Diffusivity of Tobacco Stems

Publié en ligne: 06 janv. 2015

Pages: 321 - 326

Reçu: 08 août 1988

Accepté: 02 févr. 1989

DOI: https://doi.org/10.2478/cttr-2013-0609

© 1989 Beiträge zur Tabakforschung International

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.