Wikipedia:Reference desk/Archives/Science/2018 April 19

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April 19

PC-rubber

does the "pc" in "pc-rubber" stand for polycarbonate? What is it exactly, a blend or a composite material with two separate layers? SpinningSpark 11:04, 19 April 2018 (UTC)

No. Polycarbonates (PC) are rigid thermoplastic polymers that may be transparent but are not like rubber. The commonest synthetic rubbers are abbreviated PCP (polychloroprene) rubber such as Neoprene for operating temperatures up to 95°C and EPDM (ethylene propylene diene monomer) for temperatures up to 130°C. DroneB (talk) 12:03, 19 April 2018 (UTC)

Are you sure of that? I'm seeing some sources that led me to believe it was the plastic that is meant,

• "Yee et al. have reviewed the fracture behaviour of a number of two- or three-phase blends including PC-rubber and PC-ABS blends, with some success" in Rubber Toughened Engineering Plastics
• "One can also note that the toughening mechanism in ternary blends is similar to toughening in impact resistant polymers. In the PBT–PC rubber blend, the pair PC–rubber in the process of melt blending forms the core–shell particles with rubber being inside." in Encyclopedia of Polymer Blends

Surely PBT, PC, and ABS all occuring in the same context just has to mean plastics? The context I came across this was while researching an article for Warren P. Mason who was trying to find a tougher material for sonar domes. My source says that before Mason these were made of pc-rubber but does not explain what that is. SpinningSpark 14:00, 19 April 2018 (UTC)

• If PC-ABS (ABS is already a copolymer, BTW) is meant as a combination of polycarbonate and ABS, then it's more likely to be an inhomogeneous mixture, not a copolymer. A copolymer would be called PCABS, ABSC or something. This is a fairly common material commercial (Cycoloy is one brand) which is used for injection moulding of pieces like car exterior trim. It's used, rather than ABS, because it has good impact resistance at low temperatures. The microstructure of this stuff is streaky, like wrought iron. I don't know of any true copolymers (maybe a block copolymer?) of PC & ABS.

When you said "sonar dome", my first thought was Neoprene, which is widely used for them. However for the rigid internal structure of a non-magnetic sonar array, then I could see PC-ABS as being useful for it. Andy Dingley (talk) 15:00, 19 April 2018 (UTC)

• That's a US government term for Neoprene, without mentioning any commercial brandnames. There's probably a federal law against Hoovering spilled Coke off the Naugahyde.

Polymer abbreviations are a total PITA (welcome to much of my working day). Every sub-field names its own polymers with the same acronyms. They're all "poly-" something. This one, given that it's a sonar dome, is likely to mean polychloroprene, which is a name, that no-one ever uses, for Neoprene.

It's a chlorinated rubber. Useful stuff, but it means I can't laser cut it. Unless I buy a non-chlorinated functional equivalent, which isn't as good. Unless I buy the Neoprene-branded one, which is UV-stable and weatherproof, and halogen-free: a Neoprene that's called Neoprene but is no longer neoprene. And the differences between "Plastazote" and "Evazote" (they're usually a copolymer, but it varies like crazy) are even worse. FML 8-( Andy Dingley (talk) 14:36, 19 April 2018 (UTC)

Thanks Andy, but I think you may get on better with a J-cloth than a vacuum cleaner for spilled drinks. SpinningSpark 17:03, 19 April 2018 (UTC)

1980s CIA flight? Andy Dingley (talk) 21:28, 19 April 2018 (UTC)

Southwest Airlines Flight 1380

During Southwest Airlines Flight 1380, I understand a woman was partially sucked out the window. Did they have trouble pulling her back in because of the pressure? If so, would breaking another window, thereby decompressing the plane, have made it easier to pull her back in? Would breaking that second window have caused other problems, barring others being sucked out of that one too?

Anna Frodesiak (talk) 11:22, 19 April 2018 (UTC)

Nah, just open one of the plane's doors Basemetal 12:38, 19 April 2018 (UTC)

Once a window has gone (although having someone blocking this will reduce it) the plane depressurises quickly. Even if they could, the crew wouldn't attempt to repressurise it, in case of hull damage.

Nor can you break a window. Those things are extremely strong. They're already holding such a force from the cabin pressure that nothing more you can practically do to them with hand tools is going to annoy them. Andy Dingley (talk) 14:51, 19 April 2018 (UTC)

This is the latest information that I can find: "While other passengers were able to pull her back into the aircraft, witnesses reported that she was in cardiac arrest as some aboard the plane attempted to revive her". Alansplodge (talk) 17:13, 19 April 2018 (UTC)

This guy managed to crack the inner window with a punch. SpinningSpark 17:14, 19 April 2018 (UTC)

That's just the inner window though. There are three layers (two on old aircraft), it's the outer ones which have the real strength. Andy Dingley (talk) 21:27, 19 April 2018 (UTC)

Has there been any report as to whether the victim was wearing her lap belt at the time? ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:44, 19 April 2018 (UTC)

The CBS report says one victim, wearing a lap belt (no idea how tight) was injured by blunt force trauma, went out through the window, was retrieved and given CPR, but died as a result of the trauma injuries. No second victim, and I've seen one victim named but not a second. Andy Dingley (talk) 21:42, 19 April 2018 (UTC)

Hi Andy. Ah, so she wasn't stuck from inside pressure pushing her outward the whole time, right? She was stuck from being in a tight place, forced there from the initial burst of depressurization moving her half way through the window. Once stuck, the plane then completely depressurized because she did not create a perfect seal. Does this sound right? And about the now-moot matter of breaking the other window, windows are strong, yes, that sounds right. A crack from a punch (as mentioned below) is a far cry from getting through the first pane to crack the outside pane enough to depressurize a plane. Anna Frodesiak (talk) 21:24, 19 April 2018 (UTC)

I have been closely following the official investigation by the NTSB: you can watch the Day 1 press briefing. Most notably, although the claim of a passenger being "sucked out" and "pulled back in" has been reported by the media very frequently, that claim has not yet been repeated by the official accident investigators.

Notably, during the emergency, the pilot of the aircraft did advise air traffic control that one passenger had fallen out of the aircraft. The pilot's radio call in that spirit is now officially on the record - but to evaluate the correctness of that statement, it should be clear that during the emergency, the pilot never independently went back to the passenger cabin to review the situation - she was busy handling the emergency in the cockpit, and was surely repeating "hearsay" from the passenger cabin.

In addition, the pilot also reported an engine fire; at the NTSB press conference, Chairman Sumwalt also indicated that there probably was never any actual fire - but that there are many technical reasons why a pilot might have seen incorrect instrument indications of a fire. Early analysis of the factual data is fraught with complexity, and the technical details are really complicated - which is why the NTSB will spend so much effort to evaluate, and separate, the "factual" from the "probable."

At this time, the only fatality appears to be one passenger, who was not sucked out of any window, but suffered severe, fatal blunt force trauma.

NTSB will continue to update its website with factual information. Chairman Sumwalt has proposed a reasonable timeline of 12 to 15 months for the complete report. It is probable, based on the timelines for other NTSB investigations of aviation accidents, that a preliminary report will be available within a few weeks. "Generally, a preliminary report is available online within a few days of an accident. Factual information is added when available, and when the investigation is completed, the preliminary report is replaced with a final description of the accident and its probable cause."

Nimur (talk) 21:05, 19 April 2018 (UTC)

The article says that another person died later. Bubba73 ^{You talkin' to me?} 21:18, 19 April 2018 (UTC)

Surely in the next few days, more statements and assertions will become public, and we can dispassionately evaluate all of the facts. At this time I only know of one fatality.

CBS News has just published an interview with a passenger who claims to have been involved in retrieving the passenger. We will only know whether these statements are completely accurate after a complete review of all the evidence.

Nimur (talk) 21:26, 19 April 2018 (UTC)

Here is a reference to a second passenger dying. Bubba73 ^{You talkin' to me?} 21:31, 19 April 2018 (UTC)

Whoops, I misread it. Bubba73 ^{You talkin' to me?} 21:33, 19 April 2018 (UTC)

I believe that woman is the same, one-and-only fatality. Initial media reports, in classical fashion, double-counted a lot of the victims.

This brings up the important and grisly reality of first-responder discipline in a mass casualty emergency. From the textbook: ..."an ideal initial triage area should include... dedicated casualty recorders to identify, tag, register, and record initial triage". This problem is the exact reason why we use these unpleasant paper tags: you glue one to the deceased body, and you tear off the corner so you can hand it to the coroner. One tag, one fatality, no double-counting. This helps make sure that enough emergency responders are allocated to assist those victims who are still alive.

Needless to say, we all hope that our dear readers never need to use this knowledge.

Nimur (talk) 21:38, 19 April 2018 (UTC)

Speaking of CBS, it's ironic that this happened two days after a 60 Minutes report trashing Allegiant Air's safety record. Allegiant, for all its shoddy maintenance history, has apparently never had a fatality. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:36, 19 April 2018 (UTC)

Please cite evidence that the 60 Minutes piece was misleading or else don't use words like "trashing". --69.159.62.113 (talk) 22:57, 19 April 2018 (UTC)

Where did I say it was misleading? Quite the contrary - it scared me enough that if I ever had a chance to fly Allegiant, I would wait for another airline to come along. Just not Southwest. :) ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:39, 19 April 2018 (UTC)

You said "trash"ing, which means "to subject to criticism or invective; especially: to disparage strongly". It suggests malice or at least a strong expression of opinion, not responsible journalism. If that wasn't your intent, good, but I say it's a POV term be avoided unless that is what you want to imply. --69.159.62.113 (talk) 06:38, 20 April 2018 (UTC)

You should watch the report and you'll see what I'm talking about. Actually, they probably trashed the FAA as much as they trashed Allegiant. The report might be on the CBS website. ←Baseball Bugs ^{What's up, Doc?} carrots→ 07:11, 20 April 2018 (UTC)

Watching the report would not produce evidence that it was being misleading. If you mean they were, please cite evidence. If not, please stop using the word "trash". --69.159.62.113 (talk) 03:02, 21 April 2018 (UTC)

When isn't 60 Minutes misleading or just downright disgraceful in its work? Anna Frodesiak (talk) 23:04, 19 April 2018 (UTC)

Again, it can't be emphasized enough: anyone who knows all the facts about this accident can't talk to the press. For example, consider this statement from CFM. (Who are those guys? They're the people who make this little contraption). Straight from their press release: "By law, CFM cannot provide information about the accident or details related to it. You may contact the NTSB for updates."

In case you're wondering which law, that would be codified in 49 C.F.R. 830 - 831 and related sections; and usually further contractually specified in the form of a letter of understanding or a signed Party Form; and the information will become public later per 49 C.F.R. 801 and related rules.

What this means in practice is that any news you see in the mass-media is the result of an interview with someone who is categorically not an authoritative, reliable source. Interviews with witnesses are going to yield partial stories and their statements aren't yet vetted for accuracy. People who did know internal details of the investigation, and then published that information in the press, would get in trouble: in fact, in an unrelated accident and ensuing Federal investigation earlier this month, that exact scenario played out after some idiot loudmouth began releasing statements ahead of the official inquiry. If you value truth, fact, and accuracy, you need to exercise patience and let all the independent experts scrutinize the details.

When the preliminary facts are established, the first place you'll see an update is from the NTSB. After that, it's up to the mass media and their army of journalists to sensationalize those facts and sell copy.

Nimur (talk) 02:24, 21 April 2018 (UTC)

When the airplane window got broken by flying debris, the cabin pressure which is lower than atmospheric and is maintained artificially, dropped precipitously because it got sucked out by the outside air flowing around the aircraft. Such speeding air creates much lower pressure around like air flowing over a convex upper surface of an aircraft wing. The passengers survived because the masks got dropped from the ceiling and they started breathing through them. The masks made a breathing gas mix available to them. How those two males managed to breath through the masks and at the same time to have pulled the woman out of window, I cannot explain. The victim simply got sucked out because of the same force that drove the cabin air outside. It also probably cleared the cabin of everything else which was not firmly attached to the seats. AboutFace 22 (talk) 23:06, 19 April 2018 (UTC)

A startling number of passengers weren't wearing the masks properly. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:41, 19 April 2018 (UTC)

• If your head gets sucked out of the window of a jetliner at cruising speed, sudden pressure loss is the least of your worries. The aircraft is flying at more than 500 mph, so the air is pushing on your head (roughly) that speed. The details are complex, but to a first approximation the force of the air goes up approximately with the square of speed, so your head will feel approxmately 100 times the force you feel if you stick your head out a car window at 50 mph. I speculate that the victim's neck would break against the window edge or be severely lacerated by any remaining glass. This also explains why two strong men required more than a few seconds to pull the victim back into the plane. Note that an airliner at cruising altitude must operate at high speed to avoid a stall in the thin air, so the pilots could not have reduced speed to lessen the force on the victim even if they had instantly learned of the situation in the cabin and even if they were not contending with a broken airplane.-Arch dude (talk) 00:16, 20 April 2018 (UTC)

• As you say, the details are complicated, but note that the drag equation also includes the density of the fluid as a factor. The plane was at about 32,000 feet altitude, so the air pressure would have been maybe about 30% of what is is near sea level, and that factor of 100 times you mentioned becomes more like 30 times. Still plenty to cause a devastating injury, of course! --69.159.62.113 (talk) 06:48, 20 April 2018 (UTC)

New Physics? The more you think, the more questions arise. WWII fighter pilots used oxygen masks above 10,000 feet. If they did not, their judgment suffered and they passed out. Here the plane lost hermeticity at 32,000 - a standard cruising elevation and it took the pilot 10 minutes to bring it down to 4,000 feet or so. And in the meantime many things happen that required decision making, physical force and instinct. The victim was pulled out of the window by two gentlemen. Was she hanging out completely just barely holding the broken glass with her fingertips? I doubt the size of the window is large enough to allow an average person through, but this is my guess. In order to perform CPR the victim must have been positioned on the floor of the cabin. Could the mask tethers be that long to reach there? CPR is a demanding physical exertion. The nurse must have held her own mask on her face or someone was holding it for her. Many questions.

I just watched a silent movie "Girl Shy" with Harold Lloyd. One of the scenes is shot in a passenger train car. All benches are occupied except the one in the very front, on the left (as we see it). The benches accommodate two passengers only. On that bench in question sits a young lady, his heart's desire. She is next to the window. Since the train is obviously moving toward the viewer, she is in fact on the right side of the train. Harold performs a few silly attempts to find a seat elsewhere but is chased away by the passengers who occupy those. He has no choice but to sit next to the lady, but he is "girl shy" as we know. He gyrates himself toward her bench and at this moment the train enters a steep curve. The scene of the train on that stretch is shown from outside. It is obvious that the train is making a right turn. Harold loses his balance and he is thrown into that empty seat next to the girl. But she is on the concave side of the moving train, he is moving along the centripetal force which should not have been there. He should have flown in the opposite direction in fact, but of course we forgive the move makers. I think the description of what happened in the airplane that is given to us is equally confusing and unrealistic. AboutFace 22 (talk) 17:41, 20 April 2018 (UTC)

See TUC --catslash (talk) 19:25, 20 April 2018 (UTC)

That's for "young military pilots." Even the pilot of that flight was not in that category, although women have a better tolerance for hypoxia. AboutFace 22 (talk) 19:56, 20 April 2018 (UTC)

In February, we had a long discussion on the topic: loss of cabin pressure... and I linked to a few interesting videos and other resources.

For further reading, start with the PHAK, Chapter 17, Aeromedical Factors, and if you want more, you can read the complete textbook: Introduction to Aviation Physiology.

Nimur (talk) 23:15, 20 April 2018 (UTC)

• The CPR was done (per the reports I've seen) by a firefighter. Who's in similar physical condition to a pilot.

There are walk-around oxygen bottles for the crew. It would be typical for one of those to be given to any passenger who's busy carrying out CPR.

Also there are plenty of cases of CPR being given by someone who themselves is suffering from anoxia. Anoxia is variable, dependent on physical condition and sensitivity to altitude, and often manifests itself mentally first. The CPR respondent could well have had a fuzzy head and felt lousy afterwards, whilst still being able to deliver CPR. Andy Dingley (talk) 14:38, 21 April 2018 (UTC)

In 1963 TV fiction, William Shatner opened an emergency exit door at an altitude of 20,000 feet while buckled in without suffering a fatal injury.Edison (talk) 03:53, 21 April 2018 (UTC)

Now we know the truth. Flight's 1380 engine was destroyed by a gremlin :-) AboutFace 22 (talk) 14:00, 21 April 2018 (UTC)

I'm mostly in agreement with Nimur here particularly on the point about taking care on media reports. Although one thing I'd dispute is I don't think we can rule out the passenger being partly 'sucked out' the window. We just can't say it definitely happened, and even if it did happen being part outside may not relate to her death. The blunt force (or impact) trauma to the head, neck and torso thing appears to be correct, coming from the medical examiner not the NTSB (the NTSB chairperson explicitly said it was not their bailiwick).

The 'sucked out' the window thing doesn't seem to have been confirmed by anyone yet. I earlier read this story [1] (well the NZ Herald version of it [2]) which claims "National Transportation Safety Board chairman Robert Sumwalt said Ms Riordan, who was sitting next to a window, was wearing a seatbelt before she was partially sucked out of the plane." Others say the same thing or similar [3]. This seems to imply Sumwalt actually said she was partially sucked out. It seemed quite relevant to our discussion so I planned to bring it here but in something like this I wanted to take care. So I tried to verify what exactly Sumwalt said, preferably with a recording or transcript or at least with a direct quote.

I still haven't found anything and have fair doubts he actually said that. Some other sources like [4] and [5] say something like "was wearing a seatbelt and sitting next to the window". If they mention the 'sucked out' thing, they don't imply it came from Sumwalt. In fact some sources like [6] are even more circumspect "was wearing her seat belt, Sumwalt said." So did he even say she was sitting next to a window?

I've partially listened to and skimmed through using autogenerated captions both press conferences on Youtube [7] [8] (22 mins 50 seconds is about where he mentions cause of death not being on them) and can't find anything that addresses this. I can't rule out I missed it, auto generated captions aren't perfect. Still I doubt he randomly said the passenger was wearing her seat belt while in the middle of a discussion about engines. So it seems most likely either at the beginning, where he is talking about the window and passenger or in the questions but I didn't find it anywhere. He does mention her during the discussion at about 8 minutes 40 seconds and does imply she was sitting near the window that blew out on row 14 although doesn't actually say she was right next to it instead of one of the other seats, and doesn't mention anything about a seatbelt. He does mention the absence of any acrylic from the window found inside the plane.

Still I'm not saying this is completely wrong, the seatbelt thing seems so widely associated with him that that I suspect it did come from him somewhere. (Suspect but can't be sure, the media have been completely wrong in things like this before.) Either in a later press conference, some part of the press conference that was missed or in some other form. I did come across an interview he did on CNN about this crash (but only in a copyvio), so he is speaking to the media in ways besides those 2 press conferences. (Also the timeline for the ABC News source is interesting, it has the seatbelt thing after the info on the press conference suggesting it came later. Perhaps he said something somewhere after the medical examiner released their report.)

As an example of something else, I also found this where in relation to the reports of the passenger being 'sucked out', Sumwalt is quoted as saying [9] ([10]) "we have not corroborated that ourselves." and "We need to corroborate that". As apparent quotes, I'm even more willing to accept he did say that somewhere, but again I'm not sure where as it doesn't seem to be in either press conference. The lack of a clear timeline on what was said when means that I personally wouldn't completely rule out him having said she was 'sucked out'. Although given what he said earlier, I find it unlikely, since I suspect he would have made a bigger deal over confirming it which doesn't seem to be reflected in any of the sources.

Nil Einne (talk) 06:52, 22 April 2018 (UTC)

Thank you, Nil Einne. Likewise, at this time I cannot find either confirmation or refutation by NTSB of any details relating to a passenger leaving the cabin.

The website LiveATC hosts and rebroadcasts recordings of air traffic control radio throughout almost all of the USA and a few other regions in the world. These radio recordings are provided by community enthusiasts with hobbyist and home-built radio receivers; they are non-authoritative recordings; but by hobbyist standards and "free-on-the-internet" resources, they are quite thorough.

Using LiveATC archives, many enthusiasts have stitched together the events of Southwest 1380.

Here is one such video, with English transcript: with transcription; and here is another with a map overlay and a hobbyist's reconstruction synchronizing the radio calls with the map - whose data comes from the commercial website FlightAware.com - once again, these are commercial websites that rely on a network of home-built and hobbyist radio receivers, and hobbyist software that aggregates public record data from other sources. They are quite nice presentations; they far surpass a lot of the reporting I saw on major news outlets; but they are not official - they are not even peer reviewed for correctness!

At 8m30s in this reconstructed audio, the captain is talking to Philadelphia Approach explaining her request for emergency vehicles on the ground. "They said there's a hole and someone went out."

Taken out of context, this sounds like a passenger got sucked out of the window.

In context, we have a brief summary of the medical emergency being discussed by two persons who have not actually seen the victim, both of whom are extremely busy doing something else that is significantly more important.

If I may violate my own guidance and speculate wildly: can anybody conceive of a scenario in which a panicked crew member might speak over an intercom: "we have an injury," (long pause); "there is a hole in the airplane," (long pause, during which the victim's resuscitation events have failed, and the victim has been knocked out, in the sense that they have lost consciousness), and then over the intercom: "the victim just went out..."

And perhaps we might see how in that hypothetical scenario, a very busy pilot might summarize the emergency to the ground support team, who is asking how many firetrucks and ambulances are required: "there is a hole in the airplane and someone went out," which is the actual radio call that was made...

And we might imagine that a bunch of hobbyists - nerds who like airplanes so much that they built their own internet radio website to listen to air traffic control radio all day - might have heard that on the radio, thirty minutes before any major news website has broken the story - and those very same nerds might have misconveyed their 100% factually correct representation of the radio call, yielding a completely incorrect reconstruction of an event?

And we might surmise that a sloppy journalist with a tiny budget and a tight deadline might call upon the best experts that advertisement-supported news can buy - and after Googling the event for 11 minutes, that journalist might publish a fact-based verified story so sensational that ad-revenue ticked up for 37 minutes after the story broke. Suddenly, major network news is looking to interview the firemen who performed CPR on the woman who got sucked out of the airplane; meanwhile they can't even correctly tell you how many dead bodies they counted.

Welcome to the real dystopia of fake-news: nobody even meant to make this stuff up!

So: we can understand why this statement might lead to wild speculation. Recognizing how our modern mass-media does not always hold itself to high standards for verification of basic fact, I would believe that a rumor-mill might have rapidly emerged to give credibility to an entire narrative based entirely on one statement from one non-authoritative transcript of an official-sounding thing. In view of the role that non-professional journalists now modulate the mass-media's narrative by enveloping it in "social media", it becomes harder and harder to prove where the story came from, and to demonstrate that every part of a narrative is substantiated by truth.

I do not know if the statement about a passenger who "went out" is correct or incorrect; I do not have all the facts; but I would again emphatically remind our readers by quoting NTSB: "Such releases of incomplete information often lead to speculation and incorrect assumptions about the probable cause of (an accident), which does a disservice to the investigative process and the traveling public."

Nimur (talk) 15:14, 22 April 2018 (UTC)

One thing which occurred to me I remembered reading something in one of the sources. Initially tried to find it again by general searching but couldn't. Came back here and checked all the sources and fortunately it was in them. The last WaPo source says:

Riordan died of blunt impact trauma to her head, neck and torso, Philadelphia Department of Public Health spokesman James Garrow said Wednesday night.

“The listed cause of death seems consistent with what we’ve heard in media reports,” he said, though he could not confirm the nature of her death. “The cause that we’re listing and have written on the death certificate sounds consistent with what has been reported,” he said, but he could not say whether the injuries were caused by “the fuselage or the air or the window or debris.”

I was initially thinking this was referring solely to blunt impact trauma being the cause of death or maybe that it was ruled accidental. However thinking about it more, I believe I'm wrong, especially since the 'blunt impact/force trauma to head, neck and torso seems a very specific wording which I don't believe was mentioned before the medical examiner's office made these statements. (Actually I was initially thinking when I wrote my first reply that the part came before they later confirmed the cause of death as I didn't read it properly.)

While it's difficult to say for sure without a more complete transcript I think the spokesperson did directly state the cause of death and then followed up with the additional comments which were relating to whether what they saw/found was consistent with media reports on how she died i.e. she was partially sucked out.

I'm not an expert on medical examiners, but I would imagine they could provide an educated guess even without any studies on the specific patterns of injuries whether it's like the injury pattern arose from actually at least partially going through the window or just hitting something in the plane (perhaps the window itself) but no part of the body going through. It seems quite likely going through even just the head for example, would be fairly traumatic in and of itself which significant associated injuries especially when there significant pressure trying to force the whole body through. Of course even from the medical examiner it's still just speculation, even if informed, without further confirmation. Hence the way the comments were worded. (There is also a witness account [11] from a nurse who performed CPR with similar conclusions although one would expect even if I suspect she realise it was likely hopeless that she was more concerned about trying to save the passenger than in examining the injuries and even an emergency department nurse may have some experience but would hardly be an expert in knowing exactly injuries would happen under what circumstances.)

Personally I'm leaning towards the 'sucked out' bit being true to some extent i.e. there was at least some part of her body that exited the plane. It seems clear that she was near the window and that it was broken which would mean significant air pressure pulling things towards the window. And while Nimur has a point on media reports and witness accounts especially in traumatic events for all the witnesses and a plane isn't exactly a good environment to see what's going on for one specific passenger near a window, normally things settle down after a while. In particular, there are generally at least some witness accounts which are closer to the truth. But while there have been questions over various aspects, I haven't seen any over the specific bit of her being 'sucked out', only the extent. (Some seem to suggest she was almost completely out, others seem to suggest a lot less.) The closest is the NTSB saying they haven't corroborated it but I'm fairly sure they'd say that about anything widely reported that they're not yet willing to confirm especially if asked about it.

Nil Einne (talk) 08:04, 24 April 2018 (UTC)

@Nimur and Anna Frodesiak: FWIW, I remembered this and looked to see the latest. I found the final investigative report [12] does mention

When flight attendant C reached row 14, she saw that the head, upper torso, and arms of the passenger seated in 14A had been pulled outside the airplane through the window. The passenger’s seat belt was buckled. Flight attendant C grabbed onto the passenger and, with assistance from flight attendant A, tried to bring the passenger back into the airplane, but flight attendant A reported that they could not get the passenger back into the airplane by themselves because of the pressure and the altitude. Two male passengers (in seats 8D and 13D) offered to help; they were able to pull the passenger back into the airplane and laid the injured passenger across seats 14ABC.

and

Before assisting flight attendant C with her efforts to pull the passenger back into the airplane, flight attendant A instructed the passengers in seats 14B and 14C to move out of the row “in case a bigger hole happened around the window.”

From what I can tell, since this came directly from interviews with the flight attendants, I think it's accepted this is a reasonably accurate summation of what happened and the passenger was partially out of the plane, probably in part accounting for the blunt force injuries to her torso. It looks like these reports actually came just over a week after the above discussion ended, with the 3rd May update, the NTSB said [13]

As they moved toward the mid-cabin, they found the passenger in row 14 partially out of the window and attempted to pull her into the cabin. Two male passengers helped and were able to bring the passenger in.

BTW the NTSB report also quotes the medical examiners report and includes something which I didn't have above:

The City of Philadelphia Medical Examiner’s Office performed an autopsy on the fatally injured passenger. The autopsy report showed that the passenger’s cause of death was “blunt force trauma of the head, neck, and torso.” These injuries were not survivable.

While I don't think it's particularly surprising that the injuries were not survivable, it does perhaps emphasise how severe they were. Nil Einne (talk) 14:53, 27 January 2020 (UTC)

Plane of sky

What is a plane of sky in scientific context ? Found in the 4th reference in the 54509 YORP article. Googling returns results in computer games, but I didn't find a definition or explanation. -- Juergen 95.223.151.37 (talk) 23:26, 19 April 2018 (UTC)

That plane would be the one defined by (rather, approximated by) projecting the right ascension and the declination seen by the Earth observer as basis vectors; orthogonal to the "depth" axis or "distance from Earth," which is the orthogonal parameter that is measured by Doppler shift in radioastronomy. Here is a paper on the role of Doppler in NEO observations: The role of ground based RADAR in NEO Observation.... (2006). Here's another paper on using optical astronomy plane-of-sky measurements to constrain the radio or RADAR observations: RADAR Astrometry of small bodies....

I guess the most important thing to realize is that those other plots in our OP's reference - the ones that are NOT in plane-of-sky coordinates - are not "what the asteroid/NEO looks like": rather, those are Doppler plots, and must be interpreted by a RADAR algorithm to estimate a best-fit for the object's true shape. This conceptual hurdle is a very important stumbling block for new initiates learning to watch RADAR.

Wikipedia has an article on one such algorithm: SAMV for pulse/doppler, suitable for the highly-technical enthusiast readers. We also have the much better and more general article on Compressed sensing.

Nimur (talk) 00:04, 20 April 2018 (UTC)

A- ion in human cells?

Is there something like an A- ion in human cell fluids? Google is not very useful in these cases, since the results that pop up are lithium-ion batteries and blodd type a-. --Doroletho (talk) 23:46, 19 April 2018 (UTC)

In what context did you see something like this? Someguy1221 (talk) 00:43, 20 April 2018 (UTC)

I uploaded a screenshot of the book: [14].--Doroletho (talk) 02:40, 20 April 2018 (UTC)

Ah, thanks. The "A" does not refer to any particular ion, but rather it's a stand in for all large, negative ions. Those would mostly be proteins (the average protein is slightly negatively charged at neutral pH). It's possible they took "A-" from a common nomenclature for discussing acids, where "HA" represents the acid, and "A-" represents the deprotonated acid, and the acid could be anything because it doesn't matter for a particular discussion. Someguy1221 (talk) 04:11, 20 April 2018 (UTC)

Depending on the context, "A" could stand for "Acid" or "Anion", but really it's just a placeholder symbol. Chemistry has standard sets of "placeholder" symbols used in specific contexts (i.e. R for hydrocarbon, M for metal, X for halogen) see Symbol (chemistry) for some examples. --Jayron32 10:58, 20 April 2018 (UTC)

I wouldn't trust the source the source you pulled that text from; looking at the figure, the intracellular ion balance is completely off - far too many anions - that would be very explosive. Klbrain (talk) 21:05, 20 April 2018 (UTC)

Those are not anions, as per Jayron above. But I think they could have shown it more clearly, to make it distinctive from single elements like Cl or K. Hofhof (talk) 12:55, 22 April 2018 (UTC)