A Iarge number of systems associated with chemical reactions can be regarded as thermally first order. The approximation with first order would simplify the analysises of a thermal transient to a great extent. In this paper, the authors have newly proposed and developed a few analytical methads by canstruction for therrnal responses. Herein, the ch.aracteristic point, which is defined as the co-ordinates of time constant and heat evolution rate far a reactive system, is originally introduced. The simple cQnstration on a tcmperature-time curve provides the characteristic point. In spite of the simpls way of derivation, the characteristic point has been shown to play an important role to evaluate the safety of reactive systenls. The similar constructions easily lead the heat evolution rate and heat transLer coefficient. The theory developed herein was demonstrated experimantally to be cotrect.

The　chemical　reaction　of　powdered　iron　with 3 wt ％ NaCI　solution　was　analyzed　by　measuring the　temperature・　The　temperature　change　with　time　showed　that　this　reaction　was　of　thermally五rst order．　The　heat　evolution　rate　remained　constant　as　long　as　the　solution　content　of　the　iron　powder was　constant，　The　heat　evolution　rate　decreased　with　the　increasing　solution　content，resulting　in　the ceasing　of　reaction　at　the　solution　content　of24％．　Time　constant，heat　transfer　coefficient，maximum heat　evolution　rate，and　maximum　rate　of　temperature　rise　were　derived　through　three　different　pro－cedures．These　procedures　gave　the　consistent　results　with　each　otheL　The　theoretical　and　experimental analyses　suggested　that　the　reaction　was　controlled　by　the　transportation　of　oxygen， The　useful　parameters　which　predicted　the　potential　hazards　were　obtained　by　assuming　the appropriate　model．

This　paper　is　a　report of experiments on a model pipeline，conducted to verify the theory that oil　temperature　change　in　a　petroleum　pipeline　causes　IN-OUT　flow　differential　as　described　in　part I　of　this　series． The　model　pipeline　consists　of　copper　pipe　with　heater　and　fresh　water　was　used　under　a　cons－tant　inlet　pressure．　A　numerical　calculation　was　also　executed　considering　variations　of　viscosity，How and　temperature　distribution　caused　by　oil　temperature　change， As　the　results　of　the　experiments，the　analytical　calculation　and　the　numerical　calculation，the propriety　of　the　theory　was　veriHed　alld　it　was　revealed　that　this　theory　is　applicable　to　any　pipeline operated　under　not　only　constant　flow　condition　but　also　other　opemting　conditions.