mistermack

How does reciprocation cause efficiency loss?

An update on my pc problems. I started to get other problems, following on from the hard disk failure messages. Eventually, the computer refused to reboot, with or without the suspect secondary hard disk. In the end I had to wipe the OS and re-install. And problems persisted, without the secondary hard disk, so that certainly seems to have been a false message, caused by other problems. I now run my laptop through my big monitor, and no problems at all, even with the original secondary hard disk connected, so that was not guilty. I suspect that my desktop has a hardware fault, but it's hard to nail down. I've reinstalled the OS and it works fine for a while, then refuses to reboot. I suspect maybe the power supply, USB connections or graphics card, but it's still hard to nail it down. It might even be something malicious in the graphics drivers. I use IOBIT driver-booster to install the drivers when re-installing, and the pc refused to reboot after I downloaded the latest driver fro the graphics card. Driver booster has always been ultra-reliable for me in the past, so I'm loathe to put the blame there. I'm reinstalling the operating system on a fresh hard disk, without updating the graphics drivers, and so far, it's not given any trouble at all, which seems to suggest that the power supply etc. are all ok. Hey ho, the computer has been in use constantly and given no trouble for six years, so it's entitled to dish out a little bit of grief. I will be selecting a backup system in the future though. You don't realise just what losing your data would mean, till you are faced with the imminent prospect.

I implied that sun and wind are not free?? You seem to be reading between your own imaginary lines. On the subject of the cost of nuclear fission fuel, I would contend that the real cost has to include the cost of decommissioning it and storing it for as long as it's hazardous. And that portion of it's cost has inflated by a huge factor in the last fifty years. The actual market price of the raw material is depressed at present, because the demand has seriously dropped in the last twenty years. That's probably going to stay that way, but it could change, if the cost of fossil fuel spirals again.

That would be good news. Especially considering that coronavirus was initially identified as "the pneumonia virus". It's quite a change, if it's true. I wonder how long it will take to adjust the vaccines to be more tuned to the Omicron variant? We were told ages ago that modern vaccines can be adjusted very quickly.

It seems to be confirmed now, that Omicron causes a less severe set of symptoms, on average. Any suggestions as to why, when it is clearly far more efficient at infecting a host? My suggestions are 1) That the raised infectiousness somehow causes a quicker and bigger response from the immune system, resulting in a less severe illness. That might be bad news for people with a weakened immune system. 2) Maybe the raised infectiousness means that more vaccinated people are catching it, and that they are getting less ill, and therefore affecting the figures. You could check that out, by looking at the figures for the percentage of vaccinated people who are testing positive, and how it compares to pre-omicron times. 3) Because it's so much more infectious, it might be succeeding in infecting more young people than previous variants, resulting in less serious symptoms on average. I would like to see an analysis of how people of my age (71) fare on average, when they catch it, and compare that to Delta etc.

If you DON'T want a burst, I've found that along with lagging and draining, one of the best methods of stopping bursts is to leave the tap slowly dripping. It only takes a very minor flow to make the difference.

The usual answer for these type of questions is " it depends" . If you just freeze at one point, the ice will just slide along the pipe, when the pressure builds up. Ideally, to split the pipe, you need a substantial length to freeze, with the ends freezing before the centre, to contain the pressure.

That's not fuel. It's the raw material for making the fuel. The cost of Uranium fuel is low, compared to overall costs. But not negligible. Nobody said otherwise.

Not so much for that 28% of the market. Apart from the price of Uranium fuel. And apart from the price of biofuels. And apart from the fact that green energy producers are also energy consumers like everyone else, and they have to pay market rates. I think it's an incredibly stupid step to take. And with markets being driven by supply and demand, a small drop in supply can cause a much bigger hike in price, in the short and medium term. In the energy market, the demand is not so price sensitive as in other markets. People still need energy, whatever the price rises are.

While the criticisms of the ITER and DEMO project are fair enough, and widely repeated, it's worth putting them into context. Nuclear Fission plants have been around for many years now, but they still suffer from extreme delays and cost overruns, which match or are even worse than the fusion programs. Take the latest EPR station in Finland for example. Initial costs were to be 3.7 billion Euros, and it was to go online in 2009. The latest costs are well over 8 billion, and it will start generating in mid 2022. It's the inherent danger of fission, with it's added waste problems, that have made costs and timescales inflate so much. Fusion holds out the promise of costs and timescales coming down over time, not going up and up. Because safety is so much less of a concern, as is waste management. Fission plants should have got better and cheaper over time, with improved tech, but it didn't happen because of Chernobyl and Three Mile Island, and Fukishima. Also because the problem of waste was not properly taken into account at the outset. With a mature fusion industry, there is also no chance of out-of-control inflation of the price of it's fuel, as it should be self-sustaining in that regard once the production of tritium has been confirmed as a working technology. That is one of the main goals of ITER, as the world supply of tritium is very limited at present. There does seem to be a lot of investment going into fusion, in spite of the slow progress. The UK government have taken the decision to build a DEMO class spherical tokamak that will produce net electricity and have already allocated hundreds of millions for initial work and are looking for a suitable site. It's called STEP, it's wiki page is here : https://en.wikipedia.org/wiki/Spherical_Tokamak_for_Energy_Production It's planned to be producing net electricity from fusion by 2140. Other countries are making similar plans, as well as private enterprises working on slightly different fusion technologies, such as Magnetised Target Fusion, " Canadian company General Fusion is to build and operate a plant to demonstrate its nuclear fusion technology at UKAEA's Culham Campus near Oxford in the UK. The Fusion Demonstration Plant (FDP) will pave the way for a commercial pilot plant using Magnetised Target Fusion (MTF) technology and is expected to begin operations in 2025." https://world-nuclear-news.org/Articles/Fusion-demonstration-plant-to-be-built-in-UK Just by the way, does anybody else think that there is a link between the Germans closing their nuclear power plants, and the spiralling price of gas in Europe? Surely no coincidence. And a signpost to future trends in energy prices.

Not true. Smart bosses will keep an eye on their juniors, and hopefully get the credit if they come up with something. Jocelyn Bell Burnell discovered pulsars, in spite of initial disinterest by her seniors. Her boss later accepted the Nobel Prize for the discovery. And wiki says this : "In a 2020 lecture at Harvard, she related how the media was covering the discovery pulsars, with interviews taking a standard "disgusting" format: Hewish would be asked on the astrophysics, and she would be the "human interest" part, asked about vital statistics, how many boyfriends she had, what colour is her hair, and asked to undo some buttons for the photographs.[31] "

That's fair enough, but we are talking about a phenomenal amount of energy. I MW from a coal plant will be enough to supply 4,000 homes. So scale that up to 250 MW, and it is enough power for one million homes. I would like to see a breakdown of the power figures, and how much of it is incurred powering up and down, and how much is used during an actual plasma run. Also, how hot the cooling media is on exit, and whether it has the potential for adding to the electrical generation.

If there is five times as much dark matter as ordinary matter in the Universe, does that mean that black holes have five times as much content from dark matter as ordinary matter? And in that case, there would be five times as much dark matter passing the event horizon, at any instant as ordinary matter. And could that be detected as it flows into the BH ?

One thing I haven't see in any of the articles on ITER or DEMO is where all of the input electrical power is going. The figures for ITER are 300 MW electrical input, with only 50 MW heating power going into the plasma. It would be interesting to know where the 250 MW is being used. Is it because most burns will be short duration, so a lot of energy will be used up getting the system up to operating conditions? The magnet coils will obviously use power, but will it be on this huge sort of scale? If it is, it will need a hell of a lot of cooling.

I don't think it's likely to be local currents. If you grow climbing beans, they grow clockwise or anticlockwise depending on the species. I know that most grow anti-clockwise, seen from below, but runner beans grow clockwise.

What are the chances? Finding oxygen would be very odd, since there would be no green plants to produce it or sunlight to power them. The temperature on a wandering planet is likely to be extremely cold, having no light input from a star. I guess you could have interaction with a moon, giving heat to an ocean due to tidal forces. In that case, you could get bacteria that get energy from chemicals released in "smokers" like in our deep oceans.

Thanks SJ I've had a look, I have a few suggestions now, so I'll have to try out what looks nearest to what I want. My computer gave me a warning about my second hard drive in my pc. It's not failed as yet. I have about 1.5 TB of tv recorded video on it, so I don't want to lose it, but it's not giving any trouble at the moment. I'd like to have a system of keeping most of my valued files on an external disk, and be able to just update it once a week, or something like that, so that the disk isn't wearing out, being on all the time as a second internal disk.

I'm looking for a backup program to use on a home pc. Preferably free. I downloaded EaseUS Todo Backup Free yesterday, but was disappointed as it seems to only work on whole drives. I want something that will work on individual folders, and just back up the changes from the last time the folder was updated. I don't want to back up a whole drive again, just to apply the most recent changes. I seem to remember seeing that kind of thing advertised, but I don't know by who or where.

Not if you keep the heat low. Or use a camping stove outside. An alternative is to put some cooking oil in the bottom of the saucepan. Cooking oil starts to smoke at about 200 deg C so just below that would be plenty hot enough to destroy the drive and any data on the disk. A bare platter, as in the OP question, I would just dangle over the gas ring till it deformed, or use a cigarette lighter. Edit : Apparently not. The platters are made from aluminium alloy or glass or ceramic, not plastic as I imagined. I did once open one, but didn't take much notice. It looked like a dvd, so I thought that that was the material. But anyway, if you have the platter removed, then I would recommend a hammer on a hard surface. Not even the entire might of the KGB or CIA could get that working again. There was once a case of a murderer being convicted after he cut up a floppy drive platter with scissors, it held his diary and they managed to reassemble it. But he didn't make a good enough job of it, and data on a floppy was far less compressed than a hard disk.

I would guess that it's a combination of two things. Firstly, that humans are a freakish development, and that intelligent life that has comparable technology is very very unlikely. If you accept that humans are a one in a million freak, then look at what the Earth would be like without us. Chimps and Bonobos would be top of the technology tree. Dolphins and Orcas might match them for intelligence. And that would be it on Earth. Human numbers at one point dropped to the low thousands, it would easily have happened that we went extinct. So but for one freakish species, even this Earth would have been totally unable to communicate with other worlds. It's entirely possible that life would never again produce intelligence on the human scale. It might just hit a ceiling time after time, and we are total freaks. The other factor is the huge distances involved in trying to communicate. If there are technologies out there in the Milky Way, they are probably far too distant to ever be able to get a signal through. After all, we are only just now able to detect a shadow on a star, caused by a planet, at these distances. No imaginable technology could match the scale of that type of signal.

Since you're a total layman, and she's a psychology graduate, I would go with her opinion. I would say that "intrusive thoughts" covers an array of different problems, and "call of the void" would be just one of those. Since we evolved from a tree living animal, it's not surprising that we should occasionally get the odd throwback thought of launching into the air. Or is could be a faint whiff of Tourettes, where you get a compusion to do it, because you know you should not.

You're just being ridiculous. I didn't make any claim whatsoever of what ITER WILL produce. I gave my estimate of what it's potential was. As you must surely very well know. You are nitpicking to a hilarious extent. You are talking as if electricity from heat is some new untried phenomenon. It's done in every thermal power station in the world, and was first done by steam turbine in 1884. Really, I can't take this line of argument seriously.

There being a point where the reactor can produce enough heat to create all of the electricity needed to power it, with preferably some kind of surplus. From the wikipedia page on ITER : ITER's thermonuclear fusion reactor will use over 300MW of electrical power to cause the plasma to absorb 50 MW of thermal power, creating 500 MW of heat from fusion for periods of 400 to 600 seconds.[10 Just on it's own, 500 MW of heat should be able to produce maybe 250 MW of electrical power, when harnessed through steam turbines. So if that was fed back in, the input of electrical power would have a deficit of 50 MW. In other words, ITER would be getting close to powering itself. However, in those circumstances the reactor will actually be putting out 800 MW of heat, as you will have most of the heat that you put in, on top of the 500 MW from fusion. You should be able to easily generate in excess of 300 MW of electrical power from 800 MW of heat. When you look at the timeline of fusion power, a situation as above is "almost there" bearing in mind how far they have come. So what ?

While I totally agree with the points that have been made, about the REAL performance of the current crop of fusion devices, I think that there is actually great cause for optimism. Firstly, the gains in performance of fusion in the last fifty years have been enormous. If you take as your yardstick the values of Q achieved, and the duration of maintained plasma, the measured progress has outstripped the progress in computing. And right now, with the building of ITER, we are building a machine that is almost there, in terms of being able to power itself and give off surplus electricity. The projected Q values only need to be doubled, at the most. When you consider that current values are hundreds of times better than what was achieved a few decades ago, then doubling the performance of ITER is not asking a lot. I would say that it’s a dead cert bet that we will get there, it’s more a question of when. On the subject of when, there’s a big new bit of technology lurking in the wings, that will give a boost to virtually any magnetic confinement reactor, and that is the recent progress in the field of high temperature superconductors. They are testing them out at the MIT fusion facility, and the improvement in magnetic field figures is enormous, so dramatic that it looks like being a game changer. The ITER superconductors are cryogenic, and have to be kept extremely cold. You can only go so far with them, because over certain levels of magnetic field, they stop superconducting. So they impose a limit on the field that you can create. The new REBCO superconductors being tested at MIT have experimentally given double the magnetic field that equivalent super-cooled superconductors could achieve. And double the magnetic field, for engineering reasons, allows a reactor to be one tenth of the volume for the same output. The thing about Tokamaks is that what limits the output is not the availability of fuel. It’s the stability of the plasma. For a given size of plasma, when you increase the fuel input, instead of getting more power out, you get disrupted unstable plasma, which is the limiting factor. Various methods are being researched of achieving stable plasma at higher powers. The main one being employed at ITER is the massive increase in overall size, and that’s what’s cost all the money and all of the time. It was thought that with superconductors having a limit on the field strength, size was the most promising way to go, to achieve more stability and denser plasmas. With the rapid development in the REBCO field, it looks like the limits are off on field strength, or will be in the near future, so stable plasmas will be feasible at much higher power levels, in smaller reactors. The ITER project is wedded to the superconductors that are already in the pipeline. But I think that it’s highly likely that once the project has been run, and the lessons learned re tritium breeding and blanket materials, and neutron shielding and remote handling, etc etc, there will be a redesign involving REBCO superconductors, and that will boost it well past the REAL break-even point, of net electricity power output. This is the wikpedia page about the REBCO superconductors, : https://en.wikipedia.org/wiki/Rare-earth_barium_copper_oxide And here is a link to an extensive MIT presentation, about what they have done and are planning, using this technology. I whizzed through the introductions, but the meat of it is very interesting and encouraging : https://www.youtube.com/watch?v=KkpqA8yG9T4&t=2078s

Less than that. In California, it's about 5 kwhr in 24 hrs, so an average of about 200w.