mistermack

This is a rather confusing article. The eyes are kept inflated under pressure, like a balloon. Fluid is produced into the eye, and there is a drain that slowly releases it. I have glaucoma, where the drain develops a kink, causing raised pressures in the eyes. Raised pressures, over time can damage the optic nerve and cause blindness. It doesn't seem likely that fluid could just drift into the back of the eye, against that pressure. And the half gallon mentioned just has to be wrong. Having said that, the researchers would know their field, so it must be a real phenomenon. I can't see this sleeping bag actually playing any part in a Mars mission though. I would say that the planners would have to bite the bullet for a Mars mission, and provide artificial gravity, for the health of the Astronauts. You can do it with a spinning craft, made from two units connected with a tether, about 225 metres long. If the two units spin at a rate of 2 rpm, you will produce 1g of artificial gravity, without any adverse effects on the balance organs. With computer controlled balancing systems, there's no reason why that couldn't be made to work effectively. The eye problem is only one of the known health problems from prolonged zero gravity. And on a Mars mission, you might well get unknown problems cropping up that haven't been encountered up till then.

Only because the lockdowns were not real lockdowns. It worked in China, and that's one fifth of the globe right there. And even in China, the lockdowns were a bit leaky, but as I said earlier, they eradicated it apart from returns. What China couldn't control was it's borders, they really needed some kind of wall.

Probably right. A lot of stupid things were done, but I can't think of any worse than that. What's depressing is that if a new pandemic happened, maybe in three years time, they would do exactly the same again. Partly because politicians are not particularly bright, and partly because their own popularity comes before everything else.

I can remember quite clearly when it was starting to spread in China, it was known just how serious it was. ( Remember that at the start, the death rate was over five percent of cases, so it was really regarded as a real threat ). Very shortly after that, it popped up in Korea, and Italy. But at the time, lockdown was really effective, even though the lockdowns were very sloppy. China cleared the virus, and was just getting about five to ten cases a day from returning travellers. If Korea and Italy, and any other countries that got cases locked down the affected area, as soon as a case was notified, they could easily have eradicated it in each new outbreak. Time after time, countries have underestimated the threat, and overestimated the negative effects of lockdown. After all, if they HAD eradicated it, with drastic lockdowns, the world would be far better off now. We are all paying the price of a failure to bite the bullet.

I believe that the horse has already bolted, with covid-19, because it is now so incredibly contagious. But it wasn't originally. Lock downs had a dramatic effect originally, but they didn't persist with them, they just locked down till cases dropped, and then they took the foot off the brake. That's no longer an option with omicron. Your average lock down will hardly affect it. But for the NEXT pandemic, given what we now know, it should be easy to nip it in the bud. Unless it is immediately very highly contagious, right from the word go, which is possible but not very likely. The thing with human rights is that they don't actually exist, unless we make them. They only exist in our heads, and as such, they can be anything we decide, as a society. I'm in favour of keeping them high, but certainly, they don't come before lives and health. They are a compromise, just like all other laws.

Yes, but that's just a tiny proportion of the overall energy budget. And the tritium will release the energy again when it's used later. Wikipedia has this about the neutrons : "In a production setting, the neutrons would react with lithium in the breeder blanket composed of lithium ceramic pebbles or liquid lithium, yielding tritium. The energy of the neutrons ends up in the lithium, which would then be transferred to drive electrical production." Also this : The reactant neutron is supplied by the D-T fusion reaction shown above, and the one that has the greatest energy yield. The reaction with 6Li is exothermic, providing a small energy gain for the reactor. The reaction with 7Li is endothermic, but does not consume the neutron. Neutron multiplication reactions are required to replace the neutrons lost to absorption by other elements. Leading candidate neutron multiplication materials are beryllium and lead, but the 7Li reaction helps to keep the neutron population high. Natural lithium is mainly 7Li, which has a low tritium production cross section compared to 6Li so most reactor designs use breeder blankets with enriched 6Li. I don't know the fraction of energy used in the endothermic reaction creating more tritium, I would think that it would be just a tiny bit of the overall energy budget, and in any case, it's just in store till the tritium is used.

I'm not with you there. Where do you think the wasted energy is going? You would have to ask the designers. But the plasma can be shut down very quickly, and the input electrical power can be switched off in fractions of a second, so I'm guessing that it's not an insurmountable problem.

Nothing. But I wasn't talking about him. At the start of this outbreak, people were dying from pneumonia. It was known as the pneumonia-causing virus. Cases were still in the dozens. But the local Chinese communist bigwigs refused to recognise it, and locked up anyone who mentioned it as an epidemic. It was well known, even at that stage, that it was dangerous. I was just inertia that let it get out of hand. If you are going to learn anything from this outbreak, it's that inertia can't be tolerated, you have to act immediately.

Because he is the last person on Earth to have it. Like there was a last person on Earth to have smallpox. If you got to that stage, you would surely lock that person up, till they were clear of it. You would be crazy not to.

Exactly. It doesn't go to keeping the plasma heated, but it's still available externally to create steam for electricity generation, so it's not wasted energy. They wouldn't. I made my original suggestion assuming that they were much closer to break even than they actually are. Having said that, the existing plant is getting on a bit now. ( 1983 in the case of JET, although it's been updated a few times ). So something designed today might be a lot closer to break even. Break even seems to have many different meanings in the fusion industry. It's about time they adopted a standardises way of describing where they are at, that gives a more realistic impression than the phrases they use at the moment. Most people, reading the phrase "break even" would get a very false impression of what it means. And the various versions of Q are misleading too. A situation where a reactor can power itself and run for an extended period would be the gold standard for me. Even if all of it's output was being used to run it's own components. Once you get to that stage, you have the makings to go on and create a viable industry. From what I've read, ITER will not be anywhere near that stage. But it's successor, DEMO will be just about there. But at the current rate of progress and investment, it's about 35 years away. Having said that, all of the doomy predictions of climate change are for fifty years after that, so if a successful fusion industry kicks off mid-century, it still has the potential to mitigate events at the end of the century.

As far as I can make out, that's what the lithium blanket does. It converts the kinetic energy to heat, and also uses it to breed more tritium. The heat is transferred via heat exchangers to steam generators for electrical generation, and then, if I had my way, to district heating schemes.

When I originally posted about human rights, I was talking about right at the beginning of the NEXT pandemic, what have we learned, and what should we do differently. Experience is now teaching us that a contagious virus will evolve to me more contagious, as the pandemic progresses. So that what seems to be a manageable situation at the start, can get worse and worse. The best chance of stopping it is right at the beginning, before it mutates, and before it spreads more widely. If the Chinese had descended on every outbreak in numbers, enforcing a strict lockdown for 3 weeks wherever an outbreak happened, the virus would now be extinct. There is no doubt about that whatsoever. Locking down worked very well, at the beginning. In the UK, we got infection numbers down from 5,000 a day to 400, before they eased off the lockdown. And that was a pretty mild lockdown, no locking people in or stretching human rights. So it's an absoulte fact that if a truly rigorous lockdown routine had been followed when the virus had firs been detected, it would no longer exist, and the cost would just have been a bit of inconvenience to a few thousand people, for a few weeks. It's really a no-brainer. You kill it at the outset, and argue about the ethics later. A stitch in time saves millions.

I don't think that the energy carried away by the neutrons cannot be used. What they are saying is that the neutrons carry heat away from the plasma, requiring more input as you say, to maintain the plasma. The aim is to achieve a self-sutaining plasma, that doesn't need electrical input, so if heat moves from the plasma outwards, that tends to cool it, so you either need to be generating a surplus of heat, or be putting heat in from the grid. Obviously, generating a surplus of heat, above what is needed to maintain the plasma, is the goal. But the heat carried away by neutrons isn't waste heat, it's available for steam generation. It's just inconvenient, as it works against the plama being able to maintain itself without input. Eventually, the situation will be achieved, where the fuel input can supply all of the heat needed to maintain the plasma, in spite of the heat leaking away via the neutrons, and that would be a useable fusion power station. What I originally was suggesting was that you could make fusion economic before you reached that surplus state, by selling the waste heat in district heating schemes. But it looks like there is a long way to go before they get to that stage. At the moment, with the technology at it's current state, it appears that bigger is much better, when it comes to maintaining a plasma. That's why the ITER project is so big. Maybe, when more is learned about running a continuous plasma, they will be able to do it on a smaller scale, and plants could be sited near to cities, where the waste heat could be used. After all, if the risk of explosion or radiation leak is nil, then I don't think the public would be averse to having a plant nearby.

Not possible, but I know what the next best thing is. If there was just one person on Earth who had covid, would it be ok to lock them up for a matter of days?

Looking at the pictures, I would guess that the split was caused by land slides under water, like in the case of Mount St Helens. With or without an explosive eruption. If you imagine Mt. St. Helens flooded up to it's neck, it looks quite similar :

Human rights have always been adjustable. They have never been higher than they are at the moment. But the right to life is the one at the top. We lock up serial killers, quite rightly. Covid is a serial killer, 5.32 million victims so far, have died a lingering death. If you are harbouring a serial killer, it's not a huge price to pay, to be locked up in reasonable comfort for a couple of weeks. It's not really what I would call a breach of human rights.

I thought I was adding info. It didn't feel like quibbling when I wrote it. I do have most of the history of fusion at my fingertips though. Just like anyone who has internet access.

In the aticle that I fist saw on this, they said the hottest place in the Solar System. It's academic, as if it's hotter than the Sun's core, then that will be true. But, from memory, the temperatures achieved at the NIF lazer fusion facility are in the region of hundreds of millions of degrees, whereas here at Didcot they are aiming at 100 million degrees eventually, so I doubt if the "hottest" claim stands up. It's academic really, the temperatures at the NIF are momentary, whereas the Tokamak temperatures will will persist for some minutes, hopefully. The Tore Supra tokamak in France holds the record for the longest plasma duration time of any tokamak: 6 minutes and 30 seconds. I don't know why they made this announcement, or what's new about it. The only difference that I can make out is that this is a private enterprise. I'm saying that from memory, I can't guarantee the details. This is only about four miles from the JET tokamak at Culham, which has set several records for fusion, and I would think would compete for the title of hottest. I was expecting the article to be making some new announcement, but there's really nothing new in it at all.

So according to that, you're putting in 24 MW electrical, and the total heat output is about 40 MW, which is a poor return in heat, and certainly not economic. You could do better with ground source heat pumps. Wikipedia says this about energy extraction : In the case of neutrons carrying most of the practical energy, as is the case in the D-T fuel, this neutron energy is normally captured in a "blanket" of lithium that produces more tritium that is used to fuel the reactor. Due to various exothermic and endothermic reactions, the blanket may have a power gain factor MR. MR is typically on the order of 1.1 to 1.3, meaning it produces a small amount of energy as well. The net result, the total amount of energy released to the environment and thus available for energy production, is referred to as PR, the net power output of the reactor.[9] The blanket is then cooled and the cooling fluid used in a heat exchanger driving conventional steam turbines and generators.

I'm very surprised regarding the various claimed different values of Q. I would personally have reported the power gain as MW in of electricity vs MW out of electricity. Maybe ignoring the start up energy, but giving a figure for the plant in continuing running condition. It would have to involve an estimate for electricity out, as you couldn't get the whole shebang generating in five minutes of running. I have to admit that I assumed that the 16 MW output figure was electrical energy. Throwing in an estimate of the overall efficiency of the generation process, I was guessing that you would need 50 MW of heat to generate 16 MW of electrical power. If they really do mis-report the power gain as has been reported, then that's going to be nowhere near reality. The whole thing seems to be rather cloudy, and unclear. If you are putting 24 MW in, then you are going to get at least 24 MW of heat out. So the 16 MW figure doesn't seem to correspond to heat or electricity. You would need to do some study, to find out exactly what they are claiming.

To be honest, I think those comments are more relevant to the inertial fusion research, than Tokamak designs. The shorter the period that the experiment runs, the more energy is used in the heating up from cold. So the overall Q is depressed. With a system that is constantly running, those losses dwindle to closer to zero. There is a lot of argument over whether heating up energy should be included, and it makes a big difference to the numbers that can be claimed. Getting the energy out is done by heat exchange to steam turbine. It's not bothered with at the moment, with the record duration of a plasma being six and a half minutes, but that doesn't mean that there are fundamental problems there.

Any link for that? I havn't heard it, and it would seem to be a dishonest representation of performance. I'm not denying that it's right, but I would be amazed if it was.

I think a paying fusion technology is inevitable. In fact, I'm going to argue that it could be happening right now, given the right investment. Even with the the old Joint European Taurus (JET) that first lit up in 1983. The JET holds the current record for Q, the input / output equation, with 24 MW in and 16 MW out, a net deficit of 8 MW. So how could be made to pay? I think you could make that pay by selling the waste heat in a district heating scheme. The 24 MW input will produce about 24 MW of waste heat. The 16 MW output will probably have produced nearly 50 MW waste heat, in the process of generating the electricity. So you're looking at about 75 MW of waste heat for a net input of 8 MW electricity. In the right location, you could sell that in a district heating scheme, cutting out huge amounts of fossil fuel burning. In Sweden, half of the residential and commercial premises are heated by district heating so it's not like it's a pipe dream. So even with technology that's forty years old, you could be using fusion energy now.

Not true actually. The first fusion in the lab was achieved in 1932. It can now be sustained for far longer now. It's down to economics now. Self sustaining I agree can't be done yet, but it's only a matter of time.

I know this one is far from over, but I'm curious to see what people would do differently with the next one, what lessons we have learned from this one. Here are my own suggestions. 1) Move Heaven and Earth to nip it in the bud. We COULD have done it this time, with more drastic isolation procedures. Right at the start, we had a weakly transmissable virus, with low numbers of cases. A couple of weeks of truly drastic action would have wiped the virus out. In the UK, even with the virus established, with a lockdown, we reduced it from 5,000 cases per day to 398, between april and july 2020. But then they eased off, and now we have 50,000 a day with a much more transmissable variant. 2) Reaction times to new outbreaks need to be close to instant. Time after time, complacency has meant that the virus got going, and almost impossible to control, because a couple of weeks went by before decisions were taken. 3) We have to contemplate the unthinkable. Closing down international travel, unless the two countries are clear of the pandemic. 4) Forget human rights. Force people to isolate, locking them in if necessary, until they are truly clear of the pandemic agent. The point is that if these type of actions were taken at the very start, the oubreak would only last a couple of months at the very worst, and only a few thousand people would actually be affected. Surely a bitter pill at the start would be the best for everybody. After all, the next pandemic might be far worse than this one, and this one could get much worse yet. The fact is that this outbreak would be over in two weeks, if everybody locked down. It won't happen, but it could have at the start.