exchemist

An excellent editorial that expresses very clearly and concisely the reservations some of us have been trying to articulate about this announcement: - the huge gap between laser beam energy input and the power needed to run the lasers, - the huge and yet-to-be addressed challenges in capturing the energy released and converting it into steam to run a turbine, - the issue, once all that is solved, of bringing the costs down to a scale that enable the technology to become economic, - and finally, given that all the above will take decades of further work with a still uncertain prospect of success, the risk the paper clearly sees of people taking fusion as yet another excuse for procrastinating on the urgent issue of decarbonising the world's economy as soon as we possibly can, using the renewable energy technologies that we have in our hands already.

In a nutshell, biology comprises the scientific study of living things. It therefore seems to make perfect sense to start a course on human biology with a description of what "living" means, and then proceed to the anatomy and physiology of the human body. Cell biology concerns the structure and biological and biochemical processes that go on in various sorts of cell, so what one might think of as micro-scale biology, whereas anatomy and physiology concern organs, the functions they perform, how they interact, where they are located and how they are connected etc., i.e. the macro-scale biology. As fas heart rates go, I'd imagine smaller human beings will tend to have a faster heart rate than larger ones. So boys' hearts will beat a bit faster than those of full-grown men. But why not ask your teacher? It's an intelligent enough question. You could even ask why this should be so, which could lead to an interesting discussion.

And, for some reason, you think this stuff from over a century ago constitutes news, do you? What I said was the BBC is one of the most trustworthy news sources. News. Do you understand what news is?

The BBC is one of the most trustworthy news sources around. (That news item is from February, by the way.)

By dish soap I presume you mean washing up detergent. I suspect the issue may be to do with what types of anionic surfactant are used in each. There are many different ones. Bear in mind washing up detergent (dish soap) is designed for lifting and emulsifying the oils and fats found on used dishes, while laundry detergent is designed to do some of that that but also to remove a wide range of organic materials produced by the body, many of which are not oil or fat-based, may contain proteins, etc. Hence the bleaching agents, enzymes, polycarboxylates, etc. Laundry detergent has a more complex job, requiring a more complicated formulation. So I think the reason will be to do with some of these other components. I'm not expert on detergent chemistry, though.

Oh sure, but the NIF isn’t intended as a proof of the whole concept, just that laser induced fusion can be made to work. From what I have read, a commercial power station would rely on a steady stream of pellets being ignited in turn by the laser array. But then you have the problems of how to get the energy out in order to run a steam turbine, given that the laser equipment seems to take up all the space, how to exhaust the reaction products before each ignition, how to manufacture a stream of these pellets (which I gather have rather subtle design structure), what the neutron flux does to the chamber walls........ It has to be at least another 30 years away, I feel.

I don't think that's how it is meant to work. I think the concept is a stream of pellets, each one ignited in turn by the laser. So part of the electrical energy generated by each fusing pellet goes towards igniting the next one.

I'm sure that if and when they get a significant fraction of the fuel in these pellets to fuse, they can get back the energy needed and the losses in the laser will seem trivial. But there seem to be so many further steps to be completed in the process, before we get anywhere near a commercial reactor. I recall doomed projects like the British Advanced Passenger Train. Very clever, but too many novel features and not enough focus on developing them through to commercial reliability. It was so full of glitches that the engineering division in Swindon lost patience and designed and built their own, less advanced, High Speed Train, which was a triumph and went on to become the backbone of our diesel expresses for several decades! Once they can produce significant energy gain, how do they get the energy out and how do they convert that to electricity? We had a thread on that once before, but it seemed to me there would be big challenges in getting all that working. At least a further decade. And they've got to have a commercial scale supply of deuterium/tritium pellets to fuel the thing. Will that be simple? I doubt it. And so on. Meanwhile we get these pot-boiling "breakthrough" announcements at regular intervals, reminding me of that line in "The Right Stuff": "Know what makes this bird go up? Funding makes this bird go up." 😁

Hmm, yet more breathless "breakthrough" announcements, of which I remain rather sceptical. I wonder what they mean by net energy gain, in the context of a laser-ignited inertial confinement setup. I copy below the part of the relevant Wiki article, which suggests the definition of "Q" has been altered by the Livermore group to make it seem easier to surpass, whereas, given the very low energy efficiency of lasers, it actually takes quite a lot to emit more energy than the laser needs to run. Although most fusion experiments use some form of magnetic confinement, another major branch is inertial confinement fusion (ICF) that mechanically presses together the fuel mass (the "target") to increase its density. This greatly increases the rate of fusion events and lowers the need to confine the fuel for long periods. This compression is accomplished by heating a lightweight capsule holding the fuel using some form of "driver". There are a variety of proposed drivers, but to date, most experiments have used lasers.[16] Using the traditional definition of Q, Pfus / Pheat, ICF devices have extremely low Q. This is because the laser is extremely inefficient; whereas for the heaters used in magnetic systems might be on the order of 70%, lasers are on the order of 1%. For this reason, Lawrence Livermore National Laboratory (LLNL), the leader in ICF research, has proposed another modification of Q that defines Pheat as the energy delivered by the driver to the capsule, as opposed to the energy put into the driver by an external power source. That is, they propose removing the laser's inefficiency from the consideration of gain. This definition produces much higher Q values, and changes the definition of breakeven to be Pfus / Plaser = 1. On occasion, they referred to this definition as "scientific breakeven".[17][18] This term was not universally used; other groups adopted the redefinition of Q but continued to refer to Pfus = Plaser simply as breakeven.[19] On 7 October 2013, LLNL announced that it had achieved scientific breakeven in the National Ignition Facility (NIF) on 29 September.[20][21][22] In this experiment, Pfus was approximately 14 kJ, while the laser output was 1.8 MJ. By their previous definition, this would be a Q of 0.0077. For this press release, they re-defined Q once again, this time equating Pheat to be only the amount energy delivered to "the hottest portion of the fuel", calculating that only 10 kJ of the original laser energy reached the part of the fuel that was undergoing fusion reactions. This release has been heavily criticized in the field.[23][24] On 17 August 2021, the NIF announced that in early August 2021, an experiment had achieved a Q value of 0.7, producing 1.35 MJ of energy from a fuel capsule by focusing 1.9 MJ of laser energy on the capsule. The result was an eight-fold increase over any prior energy output.[25]

Yes I pointed out what that poster does, for the benefit of those who might be tempted to respond, and got my knuckles rapped. I had reported him as soon as I clocked him, and only made a post on the thread when I could see some people were getting sucked into his vortex of nonsense. Each forum has its own policy I guess, depending on how much the mods are willing to tolerate, each time this person returns as a new sockpuppet. Which tolerance he is now exploiting as far as he can.... I'm still learning how things work here.

You understand me perfectly well, Theorist. 😁 And that nonsense equation you have just posted is typical of your style.

Here we go again. This is more time-wasting, by yet another sockpuppet of Theorist.

It doesn’t seem simple to me. Residence time in the stomach is one thing, but that’s just the start. Absorption of nutrients in the small intestine can take a long time. And do you count the further processing and recovery of water and salts in the large bowel?

I think you've nailed it. 😁

One widely used term for these extended arrays, whether ionic or covalently bound, is "giant structures".

No thanks, that would make me lazier. Also, my experience of spelI-checkers is they sometimes get things wrong. I'm a refusenik on those, just as I am on satnavs - I prefer maps.

Actually I subscribe to one and it is not generally a problem. But there, so long as you quote the post to which you reply, that version is not changed by any subsequent edit the author may make after you have replied. That avoids the issue of replies looking nonsensical. As for abuse by trolls, that hardly ever happens and when it does the mechanism I have described ensures an audit trail of the changes can be seen by all. I quite often go back and correct typos on later reading, but obviously I wouldn’t dream of substantively altering the content of my posts. I suppose the ability to do that can make one a bit lazy in drafting. But that forum tends to have quick reactions so there is some pressure to get your response in while the topic is hot, whereas here people tend to be (!) more reflective and thorough, as befits a more intellectual place. So I’m not suggesting this place should change.

The point of ID is to insert supernatural agency at random unknown points, to supplement natural processes by miracles (i.e. suspension of the laws of nature, in favour of direct divine intervention.) Once a person has decided that is acceptable, anything is possible, and the consequence of that is that no predictive theory can be formulated. That is why ID is a science-stopper. Concerning the biblical accounts of creation, if taken literally they would just mean God suspended natural processes and worked a series of miracles. Easy-peasy. But not science, obviously. It looks as though life took about 500 million years to arise, once the planet was cool enough.

Then you should definitely read “The Life and Extraordinary Adventures of Private Ivan Chonkin.”, by Vladimir Voinovich. That is hilarious. But this is off-topic.

There was a cartoon many years ago in Private Eye showing the king on the beach and a couple of chaps in viking helmets regarding him. One is muttering "silly cnut". Though actually the story is supposed to be Cnut pointing out to his obsequious courtiers the futility of attempting to command the sea.

Well there seems to be an extra from Lord of the Rings at 32:30......... Seriously though, why are you watching crap YouTube videos, now? YouTube is full of this sort of stuff, with computerised voiceovers like this one. The "creature" looks to me like a devil's coach horse beetle, one of the rove beetles. Some clown seems to have made a mock-up of one, the size of a small dog and intercut it into the film along with footage of a real one, taken in a way that disguises the scale. The animation of the dog-sized one is very poor - as bad as 1970s Dr Who. In other words, you've been had. Here's a picture of the insect:

I always thought the derivation of Schrödinger's equation relied on the idea of a particle with kinetic and potential energy. Is that incorrect, then?

But not Europe, for some reason. But then, we have our crop circles, the Loch Ness Monster - et le Dahu, bien sûr. 😁

OK the crack about anal probes was a bit below the belt - as it were - I admit. But look, photographs have been faked long before Photoshop was born or thought of, and I don't really want to watch a long video on a subject I am highly sceptical about. Bigfoot, ghosts, the Loch Ness Monster and similar stories show that people dream up all sorts of weird explanations for things they think they have observed. Nobody has yet produced any coherent, corroborated evidence for any of this, in spite of stories having been around for decades, let alone any kind of explanatory hypothesis that can be tested. In the case of the 1950s flying saucer craze, what is known is that there was widespread worry - hysteria even - about communism at the time, in the US. There were lots of movies about aliens landing and taking over, as a metaphor for fear of the communists. I ask myself why did these stories almost exclusively relate to the USA? Why not other countries? It seems to me the most credible explanations for those UFO stories are in the realm of social psychology, rather than hard science.

No we don't assume a conclusion, we accept one. That's what we all do, all the time, when we don't have ready access to the data in question. We rely on the findings of others who have looked at it, ideally people with some relevant expertise in the field. The basic problem with these claims is the lack of reproducible evidence. Thy are just aerial Bigfoot stories, basically: anecdotes from individuals that have not been corroborated by anyone with a record of competence or objectivity, mixed up with photography that may well be bogus and can't be verified. When you also take into account the lack of a credible hypothesis for why any of this stuff might be what its proponents claim, (e.g. why would aliens visit some obscure place in the US Midwest, carry out a couple of anal probes and then bugger off, without attempting to communicate or leave a forwarding address?), one is entitled to be sceptical. These photos you have produced are famous old flying saucer pics from the 1950s. That's very disappointing. Is that really the best you have?