Skin thermal properties are difficult to measure in vivo in the steady state because there is a constant temperature gradient across the skin surface. However, measurement of skin thermal properties is postulated in quantitative evaluation for thermographic observation. In this study, imaging of the thermal inertia of the skin was attempted by thermographic measurements at a stepwise change in ambient radiation temperature achieved by quickly switching two hoods maintained at different temperatures. Using this technique, a total of 65 thermograms were sequentially recorded at intervals of 0.5 s beginning 2 s before the stepwise change. The image of skin thermal inertia was estimated by applying statistical curve fitting at each pixel of the thermograms. In addition, the emissivity and true temperature of the skin were also determined, together with thermal inertia, in a single measurement. Measurements were made at different sites on 10 subjects. The average values of thermal inertia of normal skin were scattered throughout a range from 1.4 x 10(3) to 2.1 x 10(3) W s1/2 m-2 K-1. Investigations of the relationship between skin blood flow and thermal inertia were also made by imaging thermal inertia when skin blood flow was changed by applying a vasodilator or vasoconstrictor on the skin surface. In a comparison with the data measured by laser Doppler flowmetry, the average slope of skin blood flow versus thermal inertia was 2.88 x 10(-4) V per W s1/2 m-2 K-1, and the thermal inertia of the skin with no blood flow was 1.03 x 10(3) W s1/2 m-2 K-1. The results also show an almost linear correlation between skin blood flow and thermal inertia in each individual, but inter-individual differences were also observed. The results suggest that skin blood flow distribution can be estimated by non-contact imaging of thermal inertia.

Imaging of skin thermal properties was attempted by successive thermographic measurements of the skin surface with a stepwise change in ambient radiation temperature. In order to produce the stepwise change in ambient radiation temperature, two hoods maintained at different temperatures, 20 degrees C and 60 degrees C, were mechanically switched. A total of 65 thermograms were taken from 2 s before to 32 s seconds after the hood switching. Images of skin emissivity, emissivity-corrected skin temperature and thermal inertia were obtained by least-squares fitting at each pixel of 64 thermograms. Measurements were performed on the forehead, cheek, forearm, palm and back of the hand of 10 healthy male subjects. Differences in emissivity between sites and subjects were insignificant. Significant differences were observed in thermal inertia values between sites. Great improvements in the imaging of thermal inertia have been achieved by applying least-squares fitting to 64 thermograms instead of by computations from only two thermograms as in the previous study. Non-contact measurement and visualization of skin thermal properties are significant advantages of this method.

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The EBH300 Roadheader is one of the important equipment in laneway excavation of coal mine. It composed of mechanical, hydraulic, electrical and control systems, and covered cutting, shipment and travelling. Because of its hard working conditions, the complex cutting force and load fluctuation and vibration during the working process, the mechanical parts design plays very important roll to the EBH300 Roadheader. The 3D models of the EBH300 Roadheader were built based on the engineering prototype. The mechanical characteristics were studied for further development, which included mechanical structure, the vibration modes of the cutting parts, maximum amplitudes by modal analysis. According to the result, more attention must be paid to the complex force condition, violent and irregular vibration of the cutting parts in the design.

To enhance the thermal storage capacity of building envelopes and reduce the energy consumption associated with construction, a composite paraffin room temperature phase change ceramisite for a building envelope was developed. Based on a single factor test method, 52# paraffin and liquid paraffin were heated and melted together to prepare the composite phase change material, which was infiltrated into the ceramisite by vacuum adsorption. The ceramisite adsorbed with paraffin was encapsulated using acrylic emulsion, epoxy resin, or cement paste. The sand in the traditional ceramisite was replaced with the phase change ceramisite to prepare the phase change energy storage mortar for the building application. Using mercury porosimetry, differential scanning calorimetry, and thermal conductivity detection, the phase transition temperature, phase transition latent heat, encapsulation effectiveness, adsorption rate, coefficient of thermal conductivity, and specific heat capacity of the mortar were measured for the phase change ceramisite. The results indicated the following: the phase transition temperature of the composite paraffin could accommodate the range of indoor and outdoor thermal environments (18°C–35°C); a large amount of paraffin could be adsorbed into the ceramisite interior by vacuum adsorption, with the adsorption rate being higher than 58 %; with incorporation of the phase change ceramisite, the coefficient of thermal conductivity of the mortar gradually decreased and the specific heat capacity gradually increased; and when the ceramisite ratio reached 50 %, the coefficient of thermal conductivity decreased by 51.47 % and the specific heat capacity increased by 80.6 %, indicating favorable heat storage performance.