Volume 80, Issue 6, June 2009
Index of content:
- THERMOMETRY; THERMAL DIFFUSIVITY; ACOUSTIC; PHOTOTHERMAL AND PHOTOACOUSTIC
Simultaneous measurements of the specific heat and thermal conductivity of suspended thin samples by transient electrothermal method80(2009); http://dx.doi.org/10.1063/1.3153464View Description Hide Description
The electrothermal technique is developed to simultaneously measure the specific heat and thermal conductivity of individual thin samples suspended across two heat sinks, resorting to pulsed direct currents with or without a dc offset. The temperature evolution due to Joule self-heating is recorded and compared with the numerical solutions of transient heat conduction equations using the finite volume method. The thermal conductivity is determined by the steady temperature level and the specific heat by the transient temperature rise or relaxation. This technique is applied to a thick platinum wire and the thermal conductivity and specific heat are in good agreement with the literature values. In addition, the influences of thermal radiation and thermal boundary resistance between the sample and heat sinks on the experimental results are discussed.
80(2009); http://dx.doi.org/10.1063/1.3155458View Description Hide Description
Some disorders such as circulatory disease and metabolic abnormality cause many problems to peripheral blood flow condition. Therefore, frequent measurement of the blood flow condition is bound to contribute to precaution against those disorders and to control of conditions of the diseases. We propose a convenient means of blood flow volume measurement at peripheral part, such as fingertips. Principle of this measurement is based on heat transfercharacteristics of peripheral part containing the blood flow. Transition response analysis of skin surface temperature has provided measurement model of the peripheral blood flow volume. We developed the blood flow measurement system based on that model and evaluated it by using artificial finger under various temperature conditions of ambience and internal fluid. The evaluation results indicated that proposed method could estimate the volume of the fluid regardless of temperature condition of them. Finally we applied our system to real finger testing and have obtained results correlated well with laser Doppler blood flow meter values.