Looking at the BANG video <https://www.youtube.com/watch?v=dDfRaDY2R_A> starting at 2:29, it seems likely that the sound track is behind the video track.
Why? Because the events of 2:29 to 2:30 include a clear mechanical displacement of the right end of the tube that goes so far as to mechanically displace the red-stripped device in the extreme upper right of the video frame -- all before the BANG. It seems likely that this mechanical displacement was the actual BANG event with the sound coming nearly a second later. Given that disparity, it seems pretty likely that any change in the heat profile during 2:29 to 2:30 is the result of the breach, not its cause. On Sun, Feb 8, 2015 at 4:22 PM, Axil Axil <[email protected]> wrote: > The devil is in the details. IMHO, the primary cause of the failure was > not pressure related. When the video of the event is viewed at 1/4 speed, > at 2.29 a white spot caused by high heat buildup first appears in the field > of scarlet near the point of failure. This bit of evidence shows that the > power produced at 2.29 is greatly increasing. This overheat reaction is not > caused by a short circuit in the heater element because the power is steady > at that time. As 2:29 progresses the white spot grows in size. > > The area of white expands throughout the 2.30 timeframe and at the end of > that time period, the power to the heater surges as the heater begins to > short out. The exploding sound occurs at the end of 2:30. The area of white > is at its maximum at the end of 2.30 and begins to return to scarlet > stating at 2:31 as hydrogen is venting from the tube. The power going > through the heater is at its maximum at 2:32 until 2.34. The power is > minimized at 2:35. The heater is completely shorted at 2:55 with 0 current > flow. > > There is a fration of a second starting at 2:29 before the tube fractured > as marked by the sound of explosion near the end of 2:30 when high heat is > building up at the point of failure. The hydrogen detection instrument > sounds produced by venting hydrogen does not begin until 2.30 after the > sound of the explosion. This failure was caused by explosive overheating. > > On Sun, Feb 8, 2015 at 4:12 PM, a.ashfield <[email protected]> wrote: > >> Jones Beene wrote: >> >> "If the failure was only pressure-related, it would happen near the middle of >> the cavity, which is the region of least structural strength against internal >> pressure - but since the failure (apparently) happened at almost exactly the >> place where the temperature gradient would be maximized – that explanation >> seems to fit the circumstances." >> >> I find it far more likely to be determined by a defect in the Al2O3 tube. >> The ceramic is very brittle. >> I have had those thermocouple tubes break for no apparent reason when >> inserting them in a furnace. >> They also require handling with reasonable care. >> >> >
