toucana
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Posts posted by toucana
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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.
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4 hours ago, Genady said:
I see. Thank you. Such input is a significant factor. However, it is not a Bayesian update. The latter would've been an update based on intermediate results of an ongoing search, i.e., the step 6 in Bayesian search theory - Wikipedia:
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.
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3 hours ago, Genady said:
I think that rather than Bayesian Search Theory, this information was more helpful:
Titanic director James Cameron accuses OceanGate of cutting corners - BBC News
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.
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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.
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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
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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.
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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.
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59 minutes ago, swansont said:
I know this is probably rhetorical, but we can’t know, without more detail.
A properly-designed submersible would likely have a way to surface that didn’t rely on the main control. Maybe it did, but there was a leak that couldn’t be overcome by the ballast tanks. Maybe orcas got them.
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.
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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 ?
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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.
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Operator - "Killing humans - BAD !"
Drone - ♫ ♫ "Daisy Daisy, give me an answer do...." ♫ ♫
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A US Airforce Colonel Tucker “Cinco” Hamilton speaking at a Future Combat Air & Space Capabilities summit in London, has claimed that an AI controlled drone “killed” its human operator during a training simulation to stop them from interfering in its mission. The US Airforce has denied any such virtual test took place
"We were training it in simulation to identify and target a SAM [surface-to-air missile] threat. And then the operator would say yes, kill that threat," he said.
"The system started realising that while they did identify the threat at times the human operator would tell it not to kill that threat, but it got its points by killing that threat. So what did it do? It killed the operator. It killed the operator because that person was keeping it from accomplishing its objective."
No real person was harmed.
He went on: "We trained the system - 'Hey don't kill the operator - that's bad. You're gonna lose points if you do that'. So what does it start doing? It starts destroying the communication tower that the operator uses to communicate with the drone to stop it from killing the target.
His remarks were published in a blog post by writers for the Royal Aeronautical Society, which hosted the two-day summit last month.
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On 5/21/2023 at 9:41 PM, mistermack said:
I've been nearly killed twice by electrocution. The first time was in 1953, when I was 3, my brother was six, and my mother told him to get the one-bar electric fire and plug it in to warm the dining room for tea-time. I had a tantrum, I wanted to do it, but my brother wouldn't let me, and I had hold of the bar, through the grill, and he just plugged it in. If you haven't experienced the full 240 volts, you will have no idea of the incredible power that goes through. The electric current caused my muscles to contract in my hand, so I couldn't let go. All I could do was scream, and bounce around the room. And instead of pulling the plug out, my brother went to my mother and told her I was screaming. By the time she pulled the plug out, the fire had heated up, and my hand was fused to it. Pure horror.
That's what a lot of people don't realise. If you get a shock through your hand holding something, you won't be able to let go, and chances are you're going to die. It's still my earliest memory, a miracle I didn't die.
I nearly electrocuted myself at age 2 by sticking a pair of copper rods into a power socket and switching on - blew the ring main out. I subsequently worked for quite a number of years as a theatre lighting electrician rigging 3-phase power 6.5 metres up in the air (double jeopardy - if the shock doesn't kill you, being thrown off the scaffold tower will) - so I'm probably a little wary of electrical shock hazards.
On the subject of lawnmowers - My wife was recently using a corded hedge-trimmer in our front garden, and quite neatly sheared clean through her own power cable. It was a 230 VAC supply being fed via a 30mA RCD which cut out instantly. It was a nuisance having to replace and re-terminate the supply cable - but a lot simpler than replacing my wife !
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On 5/6/2023 at 5:35 PM, TheVat said:
Once fixed a cranky butterfly valve on a Dodge Colt with a paperclip slipped on it. Maybe not applicable to this, though.
I switched to electric about 1985, and life was so much better. People hate the corded ones, but they are so much better than mucking around with the crappy batteries on the cordless ones that the mfr. claims will take 2000 charges and you are lucky to get 200 before they fail completely. And the cutting power is weak. And the batteries are the most expensive part of a cordless mower, so every four-five years you have to spend a ton of money to replace them. Corded mowers, however, last for eternity. My dad had a Black and Decker corded mower for forty years, from around early 70s, and it was in fine condition when I donated it to a Habitat store after his death. It is not difficult to develop a mowing pattern that keeps you from running over the cord. Really.
If you use a corded mower or hedge-trimmer in your garden, please remember to run the mains supply cable via an RCD (residual current device) aka a GFI (ground fault interrupter) in the US - preferably one with a 30mA tripping threshold.
https://en.wikipedia.org/wiki/Residual-current_device
These are often built into the type of cable extension reels used by handymen, or can be purchased as plug-in modules. They work by comparing the current flowing on the live and neutral sides of the supply by means of a balance transformer, along with a trip that disconnects the power instantly if an imbalance greater than 30mA is detected. This prevents a potentially fatal shock in a way that a simple over-current device cannot (fuses and thermal trips can take many seconds and even minutes to blow).
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A few years ago I took part in a public tour of the newly opened Bristol Center for Nanoscience and Quantum Information (NSQI) - a new research centre constructed by Bristol University next to the main HHW Physics building in BS6.
https://www.bristol.ac.uk/physics/facilities/nsqi//
One of the many fascinating features that caught my eye was that there was one, and only one room in the entire building equipped with old-fashioned blackboards and chalk - and those blackboards were in fact not black, but a deep emerald green !
Our guide explained that the presence of those atavistic blackboards had only been sanctioned after a prolonged argument with the theoretical physicists who insisted that they could not possibly function and perform ground-breaking research into Quantum Mechanics without the comforting squeak of a stick of chalk scratching its way across a ‘blackboard’.
Left to their own devices, the building committee would have apparently vetoed the presence of blackboards in their new research centre, because even microscopic particles of chalk dust are an unwelcome headache when creating climate-controlled, vibration free, and electromagnetically shielded laboratory spaces for nanoscale engineering research.
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"Plus ça charge, plus c'est la même chose !"
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On 4/29/2023 at 4:13 PM, TheVat said:
Har! Wonder if those old Up Pompeii shows have survived. Sounds like a series possibly influenced by Stephen Sondheim's sixties comedy, A Funny Thing Happened on the Way to the Forum. (which was also inspired by the farces of Plautus)
Frankie Howerd had previously performed in a stage version of that Sondheim musical, which led to some concerns at the BBC over a possible copyright claim. But Talbot Rothwell (of Carry On fame) who was the the principal writer of Up Pompeii claimed he had never seen either the Sondheim stage musical or its film version.
There are quite a few episodes and gag-reel excerpts from Up Pompeii available on YT. The following clip of Lurcio reading yet another non-rhyming ode penned by Nausius, the love-struck son of his master, probably gives a fair idea of the level of humour.
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On 4/24/2023 at 5:57 PM, TheVat said:
May need a British --> American translator. I gather the peace sign, when held up backwards in UK, is a rude gesture. Not sure about the image source. Anyway, agree the new payment requirement is crap.
Frankie Howerd's best known catch-phrase was "Titter Ye Not !" - So the caption should probably have read "Twitter Ye Not !" 😉
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22 hours ago, TheVat said:
Seems to be spreading. Don Lemon, of the infamous Nikki Haley (51) is past her prime remark, has just been booted by CNN.
Wonder where Tucker will tan his testicles now.
According to NBC News, Russian TV networks including RT (Russia Today) have offered him a new job as a reward for his relentlessly pro-Putin rhetoric.
Vladimir Solovyov (a principal RT anchor and satirist) wrote - "We'll happily offer you a job if you wish to carry on as a presenter and host! You are always welcome in Russia and Moscow, we wish you the best of luck."
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3 hours ago, TheVat said:
May need a British --> American translator. I gather the peace sign, when held up backwards in UK, is a rude gesture. Not sure about the image source. Anyway, agree the new payment requirement is crap.
The actor is British comedian Frankie Howerd in his leading role of Lurcio, the down-trodden slave in the early 1970s BBC TV comedy series 'Up Pompeii' - (He just seemed to bear a passing resemblance to a certain well known US tycoon.)
https://www.comedy.co.uk/film/up_pompeii/cast_crew/
The comedy series which is set in Pompeii just before its destruction by the eruption of Vesuvius in AD 79, was loosely based on the Latin plays of Plautus. It follows the scheming adventures of Lurcio as he manipulates his master Ludicrus Sextus, his wife Ammonia, and their aptly named son and daughter - Nausius and Erotica respectively.
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Another way of combatting conspiracy theories is to get the principal purveyors fired from their cosy jobs as prime-time TV anchors on far-right channels, by suing the media corporations that employ them for $1.6 billion in damages for defamation.
https://edition.cnn.com/2023/04/24/media/tucker-carlson-fox-news/index.html
Fox News have just announced that both Tucker Carlson and Dan Bongino have already been terminated. More to follow as they say.
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New Twitter owner changes blue tick verification policy yet again...
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OceanGate Submersible Goes Missing During Titanic Dive
in Engineering
Posted
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.