Using the Transient Plane Source technique, various geopolymers, metakaolin-derived sodium (Na), sodium-potassium (NaK) and potassium (K), were tested to determine the effect of varying environmental conditions, such as temperature and humidity, on thermal conductivity. The results concluded that the thermal properties of the geopolymers derived from metakaolin are not greatly affected by the Si/Al ratio in the as-cured state. When the sodium geopolymers were tested at 50% relative humidity, the ...
Author(s): G. C. Lukey, J. S. J. van Deventer, P. Duxson
The measurement of thermal and ultrasonic properties of biological tissues is essential for the assessment of the temperature rise induced in vivo by diagnostic ultrasound. In this paper, we present measurements of thermal conductivity, thermal diffusivity, speed of sound and ultrasonic attenuation of fresh ex vivo porcine tissue, namely 'muscle' (from abdomen and leg), 'skin with subcutaneous fat' (from abdomen and leg), 'abdominal fat' and 'bone'. The measurements of the ...
Author(s): A. Shaw, D. K. Nassiri, G. Terhaar, I. Rivens, K. Lozhken, M. A. El-Brawany
Thermal conductivity and thermal diffusivity of two poly(methyl methacrylates) were measured using multiple methods; temperature wave analysis, laser flash, transient plane source, transient line-source probe, and heat flux meter. The main reasoning behind this study was to compare results between methods, to ensure repeatability among methods. Good agreement was shown among thermal conductivity and thermal diffusivity results between instruments, however the transient plane source method repeatedly yielded 6% higher results ...
Author(s): A. Dawson, B. Hay, C. Allen, H. Lobo, J. Morikawa, L. Halldahl, M. Rides
The thermal conductivity and thermal diffusivity of SRP (sisal-reinforced polyethylene), GRP (glass-reinforced polyethylene), and GSRP (sisal/glass hybrid fibre-reinforced polyethylene) were tested from 120 to 350K. Results showed variances in thermal conductivity values with varying temperatures in materials containing different orientations of sisal fibres. Due to the anisotropic nature of the SRP fibre, there is a difference in the thermal conductivity readings from the parallel to the perpendicular direction. The GRP ...
Author(s): C. Pavithran, G. Kalaprasad, G. Mathew, P. Pradeep, S. Thomas
When thermal conductivity and diffusivity are measured with a thermal constants analyzer, sensors of different designs are being used. Sensors are primarily made of nickel foil, arranged in a double spiral, sandwiched between two thin sheets of insulating material. For experiments between 30 and 450 K, the polyimide Kapton has been used as the insulating material. For experiments being performed at temperatures above 450 K, but below 1000 K, Mica can be used as ...
Author(s): L. Halldahl
