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Everything posted by mistermack
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Room temp superconductor, or just very good conductor?
mistermack replied to TheVat's topic in Science News
It's just a badly written summary. Very badly written. My own summary would be " The recent report of superconductivity in nitrogen-doped lutetium hydride at near-ambient pressures and temperatures has attracted great attention but also continuing controversy. Here we present work done that bears very little relevance to those conditions. However, if you are interested in superconductivity under conditions of near-ambient temperatures but enormous pressures, read on ! " -
Room temp superconductor, or just very good conductor?
mistermack replied to TheVat's topic in Science News
Ah, I see there's a discrepancy between the extract quoted in the OP, and the actual linked article. In the OP it says near-ambient temperatures and pressures. Correction : They are just unclear what they are trying to achieve. They start by talking about near-ambient temps and pressures, but then perform experiments at high pressures. It could have been made a bit clearer, (for the likes of me) -
OceanGate Submersible Goes Missing During Titanic Dive
mistermack replied to toucana's topic in Engineering
It's quite astounding that they didn't do the most basic operational checks, when the sub was first put into the water, prior to submerging in this video. Fitting the propeller wrongly, and not testing it properly, and then not doing a basic manouvering test before diving, it's all amazing stuff, and really sheds light on the general attitude of mind pervading the operation. I wouldn't want to get in a taxi run that way, let alone a sub, and especially not a super-deep-diving sub. -
Room temp superconductor, or just very good conductor?
mistermack replied to TheVat's topic in Science News
I'm struggling to make sense of this. They are talking about superconductivity at ambient temperatures and pressures, but the pressures they display in the graphs are in the region of kbars. Have I got the multiples wrong? I thought a kbar would be 1,000 bar which is hardly ambient in my book. There's obviously something I'm not getting, but I can't see what it is. -
OceanGate Submersible Goes Missing During Titanic Dive
mistermack replied to toucana's topic in Engineering
I'd like to know what means they use to control the ROV. If it's so hard to maintain communication with the Titan, how come they manage it perfectly well with ROVs, and have been doing so for decades ? The ROV that found the wreckage of the Titan did so quickly and easily while being controlled from it's mother ship. This page : https://oceanexplorer.noaa.gov/facts/rov.html#:~:text=These underwater machines are controlled,the operator and the vehicle. describes how they use electrical cables, sending control instructions down and live video and stills up to the operators, so the weight of cable is clearly not a technical prohibiting factor for communicating with the sub. If you can do it with an ROV, then all of the technology is obviously already there, and they much have made a choice to not use it on the Titan. -
OceanGate Submersible Goes Missing During Titanic Dive
mistermack replied to toucana's topic in Engineering
It's becoming clearer that there has been a lot of "news management" in this incident. I posted earlier that there would have been a very loud bang when the sub imploded, and that they would surely have heard it, or at least detected it on the ship. We now know that the coastguard was told of that noise immediately, and they would have informed those on the ship. So even if they didn't hear it themselves, they knew something had gone bang, and that could only have meant one thing, unfortunately. And that's why they found the wreckage so quickly. They knew it had gone bang. They knew exactly where it was when it went bang. And as the sub was only about 15 minutes off the bottom, they knew that the wreckage would be directly below that spot, exactly as James Cameron said. So as soon as the ROV arrived, it went straight to the wreckage. So all the talk about oxygen supplies, and the scanning the surface, was just to cover the one-in-a-million chance that the sound of the collapse was a freak false lead, but they all knew in their heart of hearts that the worst had happened. I'm quite claustrophobic, I wouldn't even go in a cave or a mine, unless I had to. I sometimes look up in wonder when I'm on the ground floor of an office block, and picture the lot coming down on my head. So I can't imagine how people can go down to those depths voluntarily. If I was going down 300 feet, I would like to see the reports where it had previously been tested down to 1,000 feet. Minumum. But that doesn't seem to be the case with Titan. The testing seems to have been only to a small percentage over the Titanic depth. I just couldn't handle the thought of that. But the weird thing is that the people who died on the Titanic would have felt no hint of danger, dressed up for dinner or dancing on the ballroom floor. But they were actually in just as much danger as these five. It's a strange world. -
OceanGate Submersible Goes Missing During Titanic Dive
mistermack replied to toucana's topic in Engineering
Eerily like the Titanic disaster itself. The "unsinkable" Titanic having too few lifeboats, and not cutting it's speed when icebergs were about. And the phenomenon of one disaster causing follow-on disasters happens somewhere every day on motorways and freeways, when people slow down and look at an accident that's happened in the opposite carriageway. It's called rubber necking, and you don't have to be a billionaire to fall victim to it. One snippet of info that James Cameron came up with in an interview was that in the last communication that the ship had with Titan, they said that they had "dropped the weights" meaning that they were coming back up, so if that's right, they had some sort of clue that something was wrong. Maybe the use of carbon fibre was a mistake in this case. I'm aware that it's a very strong material in tension, but I haven't heard the same about strength in compression or shear forces. But that's just my speculation. Others were wondering about the window material. It might be that we'll never know. Normally, these things are tested to destruction at the design stage. Sending an unmanned craft down to much deeper depths multiples of times would give you more confidence, but it would probably make the whole project uneconomic to do that. -
OceanGate Submersible Goes Missing During Titanic Dive
mistermack replied to toucana's topic in Engineering
I think it's highly likely that the sound of the implosion was heard on the ship, but they couldn't face announcing it, knowing that it might call a halt to the search and rescue endeavors. A lion's roar can be heard in air from five miles away and sound travels better in water than air. They were only two miles above the Titan, and it's collapse would have generated an enormous bang. Even if it couldn't be heard by ear (unlikely I think) there would surely have been intruments on the ship that would pick it up. In their shoes, I wouldn't have mentioned it, till all hope was exhausted, so I can't blame them, if they did hear it happen.- 143 replies
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OceanGate Submersible Goes Missing During Titanic Dive
mistermack replied to toucana's topic in Engineering
It's a bit surprising that they didn't hear anything on the mother ship, when the sub imploded. Sound carrys well in water, and they were only about 3km from the sub at the time. With the pressures involved, there should have been a tremendous bang when the hull failed, but no sound was mentioned in reports. -
OceanGate Submersible Goes Missing During Titanic Dive
mistermack replied to toucana's topic in Engineering
What part of "rare occurrences" are you struggling with? I said within a fairly small margin, and my link backs that up very well. And the fact that they found parts of the sub so quickly indicates that they had a very good idea where to look, in an area "twice the area of Connecticut."- 143 replies
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OceanGate Submersible Goes Missing During Titanic Dive
mistermack replied to toucana's topic in Engineering
It was just said on the BBC that they have found identifiable parts of the sub on the ocean floor. It didn't take them long to find it, so they must have had a good idea where to look. As far as currents go, there have been lots of dives of various kinds in this location, so they would have a good idea, and it's hardly a river down there. The various video that I've seen of Titanic wreckage didn't show much sign of a significant current. They are surprisingly well known in that location, because as I said, there have been previous dives on the wreck. This is an extract for a fairly detailed page on the wreck, and includes references to the OceanGate sub. It's a good page, well worth a look. "Gerhard Seiffert, a deep-water marine archaeologist who recently led an expedition to scan the Titanic wreck in high resolution, told the BBC that he did not believe the area’s currents were powerful enough to pose a threat to a submersible, so long as it had sufficient power. “I am unaware of any currents at the Titanic site that pose a threat to functioning deep-sea vehicles,” he says. “In the context of our mapping project, the currents represented a challenge for precision mapping, not a safety risk.” https://www.ngmisr.com/en/world/4089 -
OceanGate Submersible Goes Missing During Titanic Dive
mistermack replied to toucana's topic in Engineering
I can't see why you need to search such an area. You have the gps positioning for the point where the sub submerged. The ocean currents will be known to within a fairly small margin. So they will (or should) know very accurately where the sub was when contact was lost. The unknown factor is of course what happened after loss of contact. The likelihood is that it went down, with a little drifting with the current. So they should know pretty accurately where it's likely to be, or a line that it's likely taken. But of course, it's totally dark and silent down there so even a smaller area would be a nightmare to search. -
OceanGate Submersible Goes Missing During Titanic Dive
mistermack replied to toucana's topic in Engineering
No, you're right, it's mostly glass, I just looked. I've always assumed it was hollow, I've never had any reason to check or doubt it till now. Glass is an amazing material, to be so flexible and strong. So crushing should not be a problem under pressure. The banging noise is not coming from the sub, according to the US coastguards. It was detected by a plane, apparently, which is pretty amazing in itself, but it's not surprising that it's a false lead. Like Genady said, they are either on the surface, or done for, I'm afraid. -
OceanGate Submersible Goes Missing During Titanic Dive
mistermack replied to toucana's topic in Engineering
It might be that standard fibre optic cabel simply wouldn't function at deep ocean pressures. It might get crushed so much that signals get blocked. I don't know what kind of cables are used to cross the oceans, but if they just lie static on the ocean bed, then weight wouldn't be so much of a factor, so they can be designed to be more robust and pressure resistant. Maybe you would need a special fibre-optics, that have water rather than air in the tube, so that pressures would not be a factor. In the ocean, the weight of the cable would be supported by the water, so that the weight that needs supporting would be the difference between the weight of cable, and the weight of water it displaces. With a bit of work, you could come up with a cable of neutral bouyancy that could withstand enormous pressures. Of course, what's possible is not likely to be financially viable. It's a very limited market. -
OceanGate Submersible Goes Missing During Titanic Dive
mistermack replied to toucana's topic in Engineering
I suppose you could design some floats to be deployed at intervals along the cable, to neutralise the weight of the cable. The ones near the bottom would have to be pretty rigid, to take the pressure, but if the sub can take it, then a rigid sphere of carbon could too. -
OceanGate Submersible Goes Missing During Titanic Dive
mistermack replied to toucana's topic in Engineering
If I was designing it, I would like to have a fibre optic cable running from mother ship to sub. The stuff is everywhere these days, so it's hardly a hard-to-source new-fangled idea. Apparently, losing contact was a fairly regular occurrence. Personally, I wouldn't tolerate that situation if I was running the show. Contact was lost after 1hr45m so it's not likely that they were fully descended at that point. (I'm guessing). If the rule was to abandon the dive and re-surface on loss of contact, they would have been back on top within an hour or two. -
OceanGate Submersible Goes Missing During Titanic Dive
mistermack replied to toucana's topic in Engineering
I think this is going to become known as OceanGategate. My initial reaction was that if they are not back on the surface after a few hours from losing contact, then they are done for. I can't imagine that they would continue on, having lost contact, so they should have been on their way back up after 1.5 hours or so. The fact that it didn't happen must mean that they can't surface, even in emergency conditions. It's sad but nearly hopeless, I think. I'd like to be wrong though. -
Language development in other Homos
mistermack replied to Saber's topic in Evolution, Morphology and Exobiology
There are indirect indications of language, besides sound itself. The fossilized skull can indicate developed areas of the brain that handle speech. I think it's called Broca's area from memory. There's also a development called a descended larynx, which can I think be interpreted from fossil bones. This was a development that aided voluntary breath control, which is essential for speech. Again from memory, these things are found to exist in earlier versions of homo, giving a pretty strong indication that speech is a pretty old feature in human ancestry, not recent. There is debate about this stuff. For instance, there is a difference of opinion as to whether Neanderthals had full speech. A descended larynx isn't unique to humans either, so these are indications only, not black and white proof of anything. We have a bone in the neck called the hyoid, that gives an indication of whether the larynx is descended or not, but it's just one more clue, not conclusive of anything. My own conclusion, from back when I was reading up on this stuff, was that speech is more ancient than we currently suspect. I haven't seen much to change that opinion since, but it's still just my overall impression. -
TFG or That Florida Guy? Either way, can the GOP win in 2024?
mistermack replied to Phi for All's topic in Politics
There are ways that the Republicans can win the White House. It's against the odds, but sure, it can happen. I don't think that there's any doubt as to who will be the candidate though. Unless there is some legal means of preventing Trump from running. He's sure to get the nomination. So it's Donald vs. Joe for President, barring new sensational developments. Donald will get all of his loonies out to vote for him, but the big question is, will he motivate enough "don't really care" voters to vote against him? Biden is Biden, he has his followers, but really, it's pro-Donalds vs. anti-Donalds. That's how it will play out. Whoever can persuade them to turn out will win. If you could vote on your phone, Joe would win. But you can't, so the turnout is the unknown. If I had to bet my life on the result, I would of course back Joe, and you can apparently get 3/1 in the UK at the moment, if you want to back Donald. So it's not a great outlook for any Republican voter who isn't a Donald fan. -
It is now, but that's not what John the Baptist was doing, The idea of original sin was thought up about 300 years after the death of Jesus, so for John it was just taking a Jewish "cleansing" or "purification" practice to a more extreme level, and maybe making it an initiation into his cult following.
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I don't think Jews baptise. They do use water in some rituals, sort of purification rituals. Their initiation ceremony is ritual male genital mutilation, circumcision. And the male boys are generally named at the same time. Girls are named in a little ceremony a few weeks after birth, as far as I'm aware.
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I'm willing to accept the argument that they are aliens. But so long as they are in the country legally, they can make a valuable contribution to society.
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The guy who claimed the aliens were ten feet tall took a deep breath, before he said it. Like he was thinking, "what can I get away with saying?" Children often do the same thing, just before they tell a massive lie.
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Is there evidence that early humans had curly hair? I wasn't aware of any. Head hair on humans is not likely to be retained for function, but for sexual signals. Or possibly as something for infants to cling to (in women). Or both. Curly hair might be just a result of a larger diameter of hair. On me, at least, the fine hairs seem straighter than the thicker ones. Maybe thick hairs naturally grow curly.