Numerical　estimation　for　the　flash　points　of　emulsi丘ed　fuels　were　made　on　the　basis　of　an　assumption　that emulsion　is　regarded　as　a　conjugate　solution　consisting　of　two　liquid　phases　which　are　partially　soluble　in　each other，Activity　coefficients　required　in　this　estimation　were　evaluated　by　UNIFAC　group－contribution　method． Using　this　method，the　flash　point　of　emulsified　fuels　can　only　be　estimated　from　the　literature　values． The　estimated　flash　points　tend　to　deviate　upwards　slightly，but　generally　agree　well　with　the　measured values　not only　for　the　higher　molar　fraction　values　but　also　for　the　lower　values　where　the　simple　estimation　with Raoult’s　law　is　not　available・The　mean　of　the　deviations　of　the　estimated　flash　points　from　the　measuτed　one were　L6℃for　whole　molar　fraction　values　and2．0。C　even　for　the　lower　values　than　O.9．

We　have　attempted　to　clarify　the　fomation　mechanism　for　long－1ived　and　highly　reactive　oxygen・centered gas－phase　radicals　from　the　combustion　smoke　of　polymethyl　methacrylate　and　polypropylene　using　the　ESR spin-trapPing　technique， The　combustion　smoke　was　bubble6through　benzene　without　pheny1－N－t－butylnitroれe（PBN）as　a　spin　trap，and　then　PBN　was　added　to　it　after　a　certain　delay　time・The　gas・phase　radi￠als　from　combustion　were　much longer－lived　in　the　solution　in　spite　of　its　high　reactivity　than　that　from　cigarette　smoke， In　addition，the　combustion　smoke　was　trapped　with　a　CC13F　solution　of　PBN　at一78℃，and　their　ESR　spectra were　observed　under　elevating　temperature．The　ESR　signal　increased　remarkably　at－30～一40℃，suggesting any　possibility　for　the　decomposition　of　such　a　meta－stable　oxygen・containing　compound　as　a　trioxide，and　this behavior　is　different　from　that　of　cigarette　smoke， From　the　above　results　we　can　suggest　that　long・1ived　and　highly　reactive　oxygen・centered　gas－phase　radicals should　be　produced　from　combustion　smoke　by　the　mechanism　involving　the　formation　and　decomposition　of　such a　meta－stable　oxygen－containing　compound　as　a trioxide．

Hypocenters　of　AE　in　coal　under　triaxial　compression　were　determined。AE　waveforms，elastic　wave　velocity and　strains　were　simultaneously　detected　by 18 PZT　and4strain　gauges　attached　to　the　sample　surface. The connfining　pressure　applied　to　the　sample　was20MPa．The　sample　fractured　with　fra￠ture　planes　parallel　to　the axial　stress　direction. In　the　stage　when　the　coal　sample　approached　to　the　fracture, AE　hypocenters　concentratea　on　the　fmcture plane　and　AE　swa㎜was　formed　around　the　fracture　plane，In　the　formation　process　of　the　AE　swarm，AE　gap was　observed　prior　to　fracture．Hypocenter　distribution　of　AE　was fracta1, and　the　fractal　dimension　of　AE distribution　decreased　rapidly　prior　to　fracture.