• Electrical & Electronic Materials
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• v.7 no.1
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• pp.15-24
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• 1994

For increasing the insulating proper-ties and the reliability of composite materials due to environmental aging, the electrical and mechanical characteristics of moisture absortion specimens and moisture desorption specimens were investigated. After moisture absorption wt% and moisture desorption wt% increased with time, a state of saturation arrived subsequent to a constant time. Moisture absorption constants with the layers of glass fiber showed 0.0117 in 1 layer, 0.0123 in 2 layers and 0.0152 in 3 layers. Electrical and mechanical characteristics dropped significantly with moisture absorbing in composite materials. Although moisture dried completly at 70.deg. C, it is impossible to obtain the electrical and mechanical characteristics before moisture absorption. Many defaults by moisture in composite materials exist at interface between epoxy matrix and filler.

• Korean Journal of Food Science and Technology
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• v.24 no.2
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• pp.117-121
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• 1992

The changes in sensory and mechanical texture of chewing gum during storage at various relative humidity were studied to define the quality index for the prediction of shelf-life. The initial moisture content of chewing gum was 2.57% (dry basis). The BET monolayer value at $a_{w}$ 0.19 was calculated to be 1.57% (dry basis). The sensory scores of chewing gum were closely correlated with moisture content and instrumental texture parameters with 0.1% significant level. Therefore the quality of stored chewing gum was directly related with moisture content above BET monolayer. The products became organoleptically acceptable in the range of moisture content $2.17{\sim}3.16%(dry basis)$. This range of moisture content ie equivalent to the ranges of instrumental parameter, fracture force$0.8{\sim}1.8{\times}10^{7}$, fracture modulus $1.1{\sim}2.4{\times}10^{8}$, puncture force $0.5{\sim}1.1{\times}10^{7}[dyne/cm^{2}]$ and brittleness $0.7{\sim}1.4{\times}10^{8}[dyne/cm^{3}]$, respectively.