toucana

Captions ?

An amateur video posted on YT shows the plane falling to the ground. The Russian commentary by a woman - who apparently thought it was a drone being taken out by local air defences - suggests that the Embraer jet was hit by two SAM missiles.

The TASS news agency has just reported that Yevgeny Prigozhin the leader of the Wagner Group was one of 10 people killed when a private jet crashed near the Tver Region in Russia while on a flight from Moscow to St. Petersburg. https://www.bbc.co.uk/news/live/world-66599774 Presumably it was logistically simpler than trying to position him next to an open window.

I can’t help wondering how rural conservative gun-slingers would fare nowadays if they were forced to use smooth-bore flintlock muskets that had to be loaded by ramming hand-made black powder cartridges of twisted paper, wadding, and musket balls down the muzzle with a rod ? Fanciful ? Perhaps, but that was the type of firearm that the Second Amendment was predicated on when it was originally passed in 1791. Bolt action rifles didn’t come into general use until they were adopted by the Prussian army in 1841.

The Tsar Bomba (Царь-бомба) tested by the Soviet Union on 30 October 1961 had been designed by a team led by Andrei Sakharov to have a theoretical yield of 100 Mt. For test purposes the bomb was deliberately down-rated to a predicted yield of 50 Mt by replacing much of the Uranium-238 tamper with lead. This was done partly because there were real fears that the TU-95V bomber scheduled to drop the bomb by parachute at 4000m over the Novaya Zemlya peninsula would have been destroyed by the blast from a 100 Mt detonation. The Soviet Union military leaders were also distinctly nervous about proof-firing a 100 Mt weapon over their own territory because of the radioactive fallout that would ensue. The test was scheduled to coincide with the 22nd Congress of the Communist Party of the Soviet Union, so they couldn’t take the risk of anything going wrong. (Footage of the drop) -

Back in the days of the Soviet Union, there were only two official newspapers available for reading. One was called Pravda ( Правда - ‘Truth’) - the official newspaper of the Soviet Communist Party, and the other was called Izvestia (Известия - ‘The News’) which was the organ of the Supreme Soviet. A popular salt-mine joke was that ”There is no Pravda in Izvestia, and no Izvestia in Pravda”.

There is an Omniversum Dome Theatre version of the Imax which uses a gigantic hemispherical screen. The start-up on those machines is even more terrifying, because once you have laced the film, the entire projection head is then lifted up on a massive platform jack system to the projection porthole position located some 6 metres above the floor of the projection room. There is a good YT video showing one of these rigs being set up at the IMax Dome Theatre in San Jose CA. https://www.youtube.com/watch?v=gENOhw1Q3vM

Director Christopher Nolan shot his new biopic ‘Oppenheimer’ (2023) in 70mm Imax format, and the new film has been given a rare theatrical release in that format (the first since ‘Tenet’ in 2020). The Imax format film roll for this new 3 hour film is about 11 miles long, and weighs some 600lbs. The Imax engineers not only had to design a new enlarged platter system to carry this amount of film: they have also issued a software emulator for the long defunct PalmPilot m130 hand-held PDA - because back in the day in 2002 this was the platform for the custom PDA app most often used by Imax projectionists as their ideal tool to control the long-play Imax Quick Turn Reel Units. https://arstechnica.com/gadgets/2023/07/imax-emulates-palmpilot-software-to-power-oppenheimers-70-mm-release/

Yes - a tech should know better - but attaching a variable 30v PSU to electric toys designed for 5v turns out to be quite entertaining..

A leaked copy of a transcript of the final text messages between the Titan submersible and its surface support vessel has been circulating for some days on the internet. There is a considerable amount of discussion in progress as to whether this log is veridical or not. https://www.youtube.com/watch?v=4Dj8IJbP41c The transcript indicates that an emergency of 19m duration preceded the loss of contact. The crew apparently reported that they had jettisoned their ballast weights and the craft’s metal landing frame after an abnormally fast descent, and red light alerts had appeared on their RTM (Real Time Monitoring) system which uses ultrasonic sensors to monitor hull stress. This indicates the crew had already aborted their descent and were attempting an emergency ascent. Further messages indicate the craft was struggling to ascend, and that the crew who had reported hearing crackling sounds from the aft area, had also lost the use of their A Power Bus, and had switched to the backup B power Bus just moments before contact was lost. All of which suggests that one of their main electrical battery units had been compromised.

I have seen a couple of estimates of the energies involved in the implosion of a submersible like Titan. The figures usually suggested are these: https://www.youtube.com/watch?v=aOoRLkC2wKs - The hydrostatic pressure at 3500 metres deep is around 350 atmospheres. - The speed of the implosion is around 800 kilometers/hour which occurs in less than a millisecond. - The air pocket inside the submersible is compressed and heated to around 5777ºK This compression heating of the air is momentarily equivalent to the temperature of the surface of the sun. The occupants are simultaneously incinerated as well as pulverised - which happens well within the 13ms needed to receive sensory nervous inputs. - The implosion shockwave turns into a short explosive expansion as equilibrium is regained, completing the destruction of the submersible

This sounds like an oddly specific question. Are you trying to design and build a boosted fission bomb yourself by any chance ? If so, a word of warning - You will find it very hard indeed to acquire quantities of Tritium in particular - without attracting the sort of attention from the authorities that trying to buy large quantities of green ink and certain types of paper will usually attract in the USA. Some years ago I heard a story about a physics student in Britain who embarked on a similar 'proof of concept' project and got arrested at the point where he tried to obtain the Tritium he required. His design was sent off for expert assessment which indicated that it would have been a 'fizzle' - but a fizzle of around 1 kiloton yield ! The guy allegedly wound up working at the top secret Aldermaston atomic weapons R&D station.

Another point first raised on the Sub Brief YT channel and elsewhere, is the manufacturing process involved of bonding the Titanium end-caps onto the cylindrical CF hull with an epoxy glue - as shown below in a screenshot taken from a promotional video originally published by OceanGate. Bonding such dissimilar materials with an epoxy is a highly dubious procedure to start with, because it creates a potential weak point whose real strength under a compressive stress of hundreds of atmospheres is very difficult to predict or test. But if you are going to adopt such a technique, then you don’t do it like this - out in an open warehouse space with a bunch of guys in carpenters aprons, standing on wooden step-ladders, and slopping the gunk on from a tin with paint brushes. A safety critical jointing procedure of this type should really be carried out in a sterile dust-free environment with fume extraction running, and all the operatives clad in those special lint-free white hooded suits - the sort of precautions you would normally see in publicity photos of NASA technicians assembling satellites ready for launch into deep space.

Documentary video footage taken during a previous dive by the Titan submersible about a year ago has emerged, which shows an incident when the crew discovered that one of the craft’s unidirectional thrusters had been re-installed backwards during its last maintenance overhaul. https://www.reddit.com/r/titanic/comments/14gnn9q/horrifying_footage_of_previous_dive_from_the/ The crew discovered this problem when they were 13,000 feet deep under the surface, and just 300 yards off the bow of the Titanic. The pilot found he could only drive around in circles when applying normal inputs on the PS3 controller. Instead of of aborting the dive, the pilot conducted an urgent text dialogue with CEO Stockton Rush and the crew on the surface support vessel 3 mile above, to figure out how to remap the PS3 controller inputs ("Try turning the controller around” ...) - and carried on with the dive.

Bayesian Search Methods are based on Bayesian Statistics (as your own citation points out in its first paragraph). Bayesian Statistical modelling (as far as I understand it ) doesn’t just refer to the process of making computational updates of probabilities in the light of new data - it also takes account of the degrees of belief in an event - which may be based on prior knowledge about an event - such as the results of previous experiments - or the personal beliefs about the event held by the observer. https://en.wikipedia.org/wiki/Bayesian_statistics

In the case of the 1968 search for the USS Scorpion which I cited, it was the triangulation of recordings of an underwater explosion recorded by several secret US Navy listening stations which persuaded John Craven’s team to relocate their search area to the Azores. The analysis of these audio recordings was a key input into drawing up the Bayesian probability density maps which led to the discovery of the wreck. Subsequent surveys of the wreck site disclosed that the USS Scorpion had suffered a devastating explosion in its forward torpedo room, and that uncontrollable flooding had caused the vessel to sink below its crush depth and implode - which was the event recorded by the listening stations.

The process of conducting an underwater search for a lost submarine has been based on the use of Bayesian Search Theory ever since 1968, when the technique was first successfully used in the hunt for USS Scorpion (SSN-589). This nuclear powered submarine had gone missing while returning from combat patrol to its base in Norfolk Virginia, and might in theory have sunk anywhere between there and its last known location near the Canary Islands. A team of mathematicians and acoustic specialists led by John Piña Craven calculated an optimum search box area, and subsequently located the wreck at a depth of 3047m, and within about 500 metres of the central X of the primary search box near the Azores - (The US Navy thought it had sunk off the Eastern Seaboard). https://en.wikipedia.org/wiki/Bayesian_search_theory In the case of the Titan submersible, the search teams could define an optimum ‘box’ based on the known time of the loss of contact at 1h 45m into the dive, and the planned descent route to the wreck of the Titanic.

BBC & other news sources report that a debris field has been found by an ROV from Horizon Arctic: https://www.bbc.co.uk/news/live/world-us-canada-65967464 US Coastguard has announced it will give a press briefing at 15.00 EST

Here is a link to a YT video posted by an ex-naval submariner that raises a couple of interesting engineering points about the design and operation of this submersible: * How exactly does the life-support system work ? Do they have CO2 scrubbers and filters to remove toxic gas build up? Or does it simply rely on feeding in fresh supplies of O2. If it’s the latter then you will create a high oxygen-rich atmosphere that may provoke a flash-fire like the one that happened in the NASA Apollo 1 disaster in 1967, which killed 3 astronauts during a ground test, before the hatch could be unbolted. * The hull is built of laminated carbon fibre 5” thick (the video includes a clip of the manufacturing process involved). But CF doesn’t just crack under extreme pressure, it actually shatters completely like porcelain. * The video confirms that contact with the surface support vessel relys on sonar via a Teledyne USBL (ultra short base line) DAM (data acoustic modem) transponder system that provides positional updates in real time, and also supports short text messages. There were other options available, but the CEO Stockton Rush apparently disliked the distraction of hearing non-stop chatter from the surface crew, and preferred this solution. https://www.youtube.com/watch?v=4dka29FSZac

US court filings disclose that OceanGate fired a whistleblower in 2018 who raised concerns about the safety of the glass viewing port in the submersible that has now gone missing. https://newrepublic.com/post/173802/missing-titanic-sub-faced-lawsuit-depths-safely-travel-oceangate David Lochridge who was the director of marine operations, and was responsible for the safety of all crew and clients, had voiced a number of concerns about the safety of the submersible. He was particularly concerned that the manufacturers of the glass viewing port would only certify its safety to a depth of 1300m (The Titanic lies nearly 4000m below the surface on the seabed). The submersible was built as a cylinder of 5” thick carbon fibre with Titanium end-caps. David Lochridge had refused to green-light manned tests of the submersible until further NDT engineering studies had been carried out into the effects of pressure cycling on the hull and window seals at extreme depths. "Lochridge learned that the viewport manufacturer would only certify to a depth of 1,300 meters due to experimental design of the viewport supplied by OceanGate, which was out of the Pressure Vessels for Human Occupancy (“PVHO”) standards. OceanGate refused to pay for the manufacturer to build a viewport that would meet the required depth of 4,000 meters." The submersible lost contact quite abruptly around 1h 45m into a planned 2h descent to the sea floor.

I've read elsewhere on the BBC website that a submersible of this type would normally have a hydraulically operated ballast-release system that jettisons several hundred Kilos of metal to restore positive buoyancy, and allow the vessel to float back to the surface. The hydrostatic pressure at this depth (2.3 miles underwater) is around 25,000 PSI - far beyond the 'crush depth' threshold for any normal pressure-hull submarine - so any leak would have been instantaneously terminal.

n 2022 the BBC filmed inside the OceanGate Titanic submersible that has now gone missing during a dive to see the wreck of the Titanic, which lies on the seafloor about 12,500 feet below the surface, and around 370 miles off the coast of Newfoundland. https://www.bbc.co.uk/news/av/world-us-canada-65958697 In the screenshot below, Stockton Rush the Chief Executive of OceanGate who is believed to be one of five people missing aboard the submersible is seen explaining how it works “It’s got one button, and that’s it. We run the sub with this game controller - It’s made by Logitec, but it’s basically a Sony PS style controller” he says - What could possibly go wrong ?

The full unsealed indictment of FPOTUS Donald J. Trump that was filed in the SDC of Florida - containing 38 counts under the Espionage Act: https://storage.courtlistener.com/recap/gov.uscourts.flsd.648653/gov.uscourts.flsd.648653.3.0.pdf The first judge listed on the docket as attending to the indictment next Tuesday is Judge Aileen Cannon - the same Trump appointed Article III judge who controversially obstructed the DOJ last year by enjoining the entire Federal investigation, before the appellate courts unanimously overturned all her rulings This judge is now apparently preparing to hear appeals for a summary dismissal of all charges by Trump's new lawyers - (the old ones just walked). This could get interesting very fast indeed.