Seals repeated thermal cycles

The high temperature leak rates during repeated thermal cycling were measured for the SCN-1 seal between 700 and 850°C at a differential pressure of 0.2-1.0 psi. 

The arrangement is then placed in a furnace, heated to 800°C, and the pressure decay test is repeated. The setup can be subjected to thermal cycles with pressure decay tests at room temperature and at 800°C. A good hermetic seal, however, will not show any pressure decay at a low pressure differential. The results of one series of tests using a glass composite material that has a glass transition temperature (Tg) of about 700°C, at 5 psi are shown in Figure 5.10. The combination of pressure and thermal cycle tests showed that the seal is capable of withstanding the pressure... 

The entire photolysis sequence can be reversed readily by H2, as summarized in Scheme 1 (27). A sealed, degassed benzene solution of [IrClH2(PPh3)3], from which the photoreleased H3 is not allowed to escape, can be cycled repeatedly (>50 cycles) through the photoinduced H2 elimination-thermal H2 addition reactions without any observable loss of complex. Elimination of H2 can be induced by irradiation with X < 400 nm. The quantum yield of elimination, measured at 254 nm by monitoring the growth of the 449-nm band of [IrCl(PPh3)3], is 0.56 0.03. 

For the combined EDS-batch SCWO, a variety of technical issues must be addressed the choice of materials of construction, the method used to introduce oxidant into the vessel, the durability of seals, the stability of SCWO reactions in a large-diameter vessel, the methods used to heat the vessel, the possibility of scaling and corrosion under batch SCWO conditions (salts are proposed to be captured in apan placed in the vessel, but this has not yet been demonstrated), the method used to fabricate the vessel (e.g., single forging vs. welded sections), the impact of repeated explosions followed by thermal and pressure cycles on the integrity of the EDS vessel and SCWO reactor (e.g., crack propagation), the most appropriate method of cooldown and depressurization following munition destruction, and the disposition of process residuals. 

A TA Instruments DSC 2920 (TA Instruments, New Castle, Delaware) was used to study the thermal properties and crystallinity of the microgels. Microgels with excess squalane were sealed in an aluminum hermetic pan and cooled to 0 °C in the DSC cell before being heated at a rate of 10 °C/min to 155 °C. Following this, the sample was brought back to -40 °C with a cooling rate of 10 °C/min and this process was repeated for an additional seven cycles. 

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