The stability of chemically reacting systems governed by heat balance were analysed. The parameter μ＝1一q/UA, where q was the derivative of the heat-release rate q with respect to temperature and UA was the heat conductance, was introduced. The system was stable for μ≧0 and unstable for μく0. Thus, μ was named stability index. It was difiicult to calculate μ directly from q and UA because chemically reacting system in practice continuously changes its states. Therefore, the authors proposed the new method to obtain μ experimentally and simply by slightly perturbing the environmental temperature. △Teo the temperature change of environment, and △Ts that of a system, were related to μ as μ = △Teo/△Ts. Studies on Potentially Hazardous Reactions IX

In　order　to　investigate　the　damage　process　and　its　nondestructive　evaluation　technique　in　carbon／epoxy　laminates，the　authors　applied　simulataneously　the　AE　analysis，the　stress　pattem　analysis　using infrared　thermal　imaging　and　soft　X ray　radiography　together　for　circularhole　notched［0°／90°］_2S　laminate plates　subjected　to　monotoneously　tensile　and　cyclically　fatigue－loading． The　results　are　summarized　as　follows， （1）In　tensile　fracture　process，the　AE　event　occurs　at　the　stage　of67％of　the　ultimate　stress　and　its　AE event　has　wide amplitude　distributions　different　from　that　in　cyclically　fatigue－10ading． （2）The　initial　stage　of　damage　process　occuring　during　fatigue　loading　for　a［0°／90°］2S　Iaminate－plate with　a　circular　hole　shaped　notch　has　been　suggested　to　be　the　transverse　laminar cracks　initiated　at　the　edge of　hole　notch　and　its　propagation　accommanying delamination　between　matrix　and　fibers，by　using　both　Qf infrared　thermal　imaging　stress　analysis　and　AE　analysis．And，the　facts　suggested　by　NDT　techniques　have been　connrmed　by　Xray　radiography　and　scaming　electron　microscopic　observations， （3）It’s　concluded　that　the　simultaneous　use　of　the　infrared　thermal　imaging　stress　analysis　and　AE analysis　has　been　proposed　as　a　possible　NDT　technique　for　monitQring　of　damage　process　in　the　composite materials　such　as　carbon／epoxy　Iaminates．

Recently, increase in global concentrations of mercury has become the current topics of the world. Human hair is a good indicator of mercury exposure and there has been a good correlation between the environmental pollution of mercury and the mercury concentration of hair. At present, the criterion of hair mercury as a indicator for mercury environmental pollution has been employed the mean value 6.02 ppm (n=73) of 30 years ago, i. e. the times of the mercury pollution. This mean value is commonly considered unsuitable for the present environment. The purpose of this investigation was to estimate the normal level of the present hair mercury concentrations in people who are healthy and sick persons. Mercury in hair samples were determined by gold amalgam and cold flameless atomic absorption spectrometry Here we present measurements of total hair mercury for healthy people, which show that males (n=67, mean 3.72 ppm) had a higher concentration than females (n=189 , mean 2.05 ppm) and hair mercury mean value as normal level was 2.49 ppm (n=256) On the other hand, the mercury concentrations (n=57 mean 5.9 ppm) in hair of sick persons (dementia) was at maximum 36.5 ppm and clearly about three times higher tban the corresponding value from normal level.