Posts by Persona 879 publicly visible posts • joined 6 Jul 2018
It's good to review Sizewell C's finances.
Because of it people are saying that nuclear power is needed and must be paid for. Thanks to this discussion the pro-nuclear voices are outnumbering the anti-nuclear ones who would commit us to an energy policy that could not meet demand through the year.
My washing machine has WiFi. I thought this would be absolutely pointless but it turned out to be useful. My daughter has a habit of coming over to our house using the washing machine then forgetting and going home leaving a machine full of her washing. Now I get a notification (even when I'm away on holiday) that the washing cycle has finished so I can message her to empty it.
This was certainly invoked during WWI, but I don't know if it still is, here or anywhere else.
A chap I worked with in a research lab during the early 80's had a couple of his radio related patents classified secret. The military implications of the one I recall were blindingly obvious.
It is a fiercely competitive market.
It is, but banking is also based on trust. Knowing your counterparty is not only a legal requirement, it is vital. If you accidently pay $1billion to the wrong counterparty they will return it as soon as you ask. If you don't ask I suspect they would sit on it, but you notice and ask as soon as the counterparty who should have received 'politely' enquires why you have missed the payment deadline. I am aware of this exact scenario happening despite 3 people having checked the outgoing payment details.
Precisely. As I said, to avoid accidently killing it so needing to replant, you pollard it in the winter months when there is less stress to the tree with minimal loss of sap. Insect and fungal infection is also reduced during cold months, so these possible sources of infection are not active.
In theory it does make sense. A quick growing crop like pollarded willow sucks the C02 in rapidly and after a few years it's harvested and burnt so is back to zero net CO2. The energy cost of transporting it is not substantially worse than any other fuel. Where it fails horribly is the stuff needs to be harvested at the end of the year if you are not going to kill it so have to replant and wait years for the next crop. At that time in the year the ground is wet and soft making mechanized extraction of large quantities of the wood really difficult and hence prohibitively expensive. So instead they go for the easier and hence profitable option of harvesting mature wood that has taken many decades to grow which is why the greens don't like it, and for once I agree with them.
Dinorwig is an engineering marvel, but it is only designed to even out relatively small and short time variations in supply and demand. The higher the reliance on variable renewables, the bigger those fluctuations will become. A full fill of Dinorwig stores energy equivalents to 15 minutes of average UK electricity demand. It gets worse. UK households currently use about 4 times as much energy from gas as they use from electricity. So one full fill of Dinorwig is equivalent to 3 minutes of gas and electricity power demand.
It's convenient to blame it all on the Russian invasion and whilst that does make matters worse it's just a contributory factor. Energy suppliers were going bust many many months before the invasion because the wholesale price of gas was way above what the price cap allowed them to charge customers. The BBC likes to show the spike after the invasion but now ignores the rapid increases that were already happening.
Gas is expensive because of climate change promises. Countries pledged to stop burning coal. This caused a huge increase in global demand for gas. Countries then went on to say they would be carbon neutral in 2030 or 2035. This destroyed the case to invest in gas infrastructure as "theoretically" we should have a massive excess of supply in half of that time. For example, in 2021 alone plans for about a dozen LNG terminals with a total capacity for 250 million tons of gas per year were canceled. Increased demand and reduced supply will always lead to prices increasing to the point that they become unaffordable for some.
With the SLR the standard selector lever had a lug on it that stopped it being rotated into the "Full Auto" position. I never came across a lever without the lug, but they were made and I have seen photos. I would imagine five minutes with a file would be enough to remove the lug on a standard selector. I was always led to believe a bit of aluminium foil wrapped around the inside part would do the same job (presumably like your matchstick), but as the selector lever is also the "safety" it's probably not something to be messed with.
The 'real world' moment is generating the power. Putting it onto the grid is an engineering irrelevance to the research. Whilst the first solar connection to the grid was probably even smaller, that was a long long time ago. Now it's just routine commodity stuff, not "cutting edge" research. You can just get a "Grid Tie Inverter" from ebay that does the "stringent" stuff. It that takes the generated electricity in at one end and feeds the grid at the other. If it's a different frequency/voltage coming out of their generator that the Grid Tie needs then so what just put another convertor in between and you are done.
However, the fact that the lab was able to connect its test loop directly to the grid is a huge deal, said lead researcher Darryn Fleming
So they connected their 10kw generator to the grid......... Aren't there millions of rooftop solar power installs around the world that generate several kilowatts of electricity and put them onto the grid? No doubt there are stringent requirements that need to be met in order to do this, but doing so is hardly cutting edge research.
But will the sprog look after you when you are old an decrepit? It becomes a long and tedious task with zero reward particularly when the old person has no idea who you are. A residential care home then becomes the option, but this is very expensive as it needs to employ lots of people to do all that routine and boring work and "interact" with the residents. The numbers start to look impossible with an aging population. A humanoid robot could be the solution in this environment. It doesn't need to be terribly smart to do the 90% of routine work. The "smart" bit is it determining if it's the 10% of situations where a real person is needed.
I for one would be quite happy for humanoid robots to be caring for my mother in law who suffers from severe dementia and resides in a care home costing £4468.64 per month.
It may have had voice activation too. If so no need to take your eyes of the road: just press the "voice" button on the steering wheel and say "blower level 3" or "increase fan speed" though I would be more inclined to say "set temperature to 19".
A car with just a touch screen and no buttons needs good voice command processing, and that needs chips.
Decent bus services require high population density and relatively limited directions of travel e.g. to school.
There are a few busses where I live. Mostly they only have 2 or 3 passengers and they are going to only 4 of the 60 destinations I commonly want. Changing busses a couple of times would be very time consuming. Looking on Google maps a 45 minute car journey I did on Friday would have taken over 2 hours by bus (3 busses actually). The journey back would be no better plus we stopped at 3 shops on the way. It added little distance, but would put the bus journey time up to three hours or four if the timing was bad. I really don't want to spend 5 or 6 hours sitting on or waiting for busses even if they were free.
Carbon neutral jet fuel is not a new concept. This development is just another chemical process for making it. Siemens and others have been working on it for some time.
In March 2021 Rolls Royce flew an Airbus A350 on 100% synthetic fuel https://www.theguardian.com/business/2021/jun/17/rolls-royces-jet-engines-to-run-on-synthetic-fuels-as-part-of-net-zero-plans
Being big evil corporations they are only going to be doing that if it makes them more profit.
What is the return on that analysis? How can it manage to be so valuable that it not only pays for those expensive endless gigawatts of electricity but also turns a nice and evil profit at your expense?
China was crippled under Mao and kept as a rural peasant economy. With nothing much to start with the fastest way to progress was for them to copy what others have and spend on education. Copying is near instant, but it takes a long time for the investment on education to pay back as first you need to teach the teachers. I believe there are now more than 3000 universities in China with 50 million pupils enrolled. Currently there are 22 Chinese universities ranked in the top 200 in the world. It's a given that they will be copying the ASML lithography. It's also quite possible that they are developing new and better stuff.
tbh I'd rather keep intervals exact and live with an extra inserted second, than have intervals perhaps off by a few hundred ms, if they're a few hours in length
When the leap second is inserted NTP maintaining time on equipment will smear it over a period of time to correct all of the computer clocks. What you are fearing is already the norm.
Exactly. Because it matters they account for the human IERS decision to add the leap second or not. They will not stop working because the extra second is added this year or next or even deferred for years. It's just an offset that builds up and gets nulled out from time to time. It built up to 10 seconds before we started nulling it out. If we hadn't done anything it would now be 37.
Now it won't due to storing the cron times as UTC. This was done as the bug fix for some older Unix versions where it just had the text versions of the dates. Some other variants (HP for sure) also had an obscure cron bug that applied if the server was rebooted in that magic hour.
I understand the problem leap seconds are solving, but do we need them? We are talking about a difference between two ways of "measuring" time that diverge by about a minute every century. If we just just stop adding them and let the two diverge it it's going to take >5,000 years for it to make an hours difference. We are very happy and generally cope with applying an arbitrary one hour DST correction to our time a couple of times a year (with the exception of those countries that don't do DST). All that would need to be done to fix the divergence of the two time systems would be to cancel one of those two arbitrary DST changes every 5,000 years. The people who need to be aware of the difference between the two methods already are familiar with there being a offset between them and how this changes as leap seconds are added. They should be quite capable of coping with this offset getting a bigger over the next 5,000 years. For the rest of us its a minor change to the way the DST change is calculated in 5,000 years.
we can put our differences aside
People don't like wars and international tension disrupting their stuff. Even during wars essential trade can still happen. During the First World War the only khaki dye available for British Army uniforms was manufactured in Germany and secretly imported to the UK. Both sides agreed that they couldn't have troops fighting in the wrong colour uniform.
It's not that strange. Whilst SpaceX's fleet leaders are at 13 flights, sources suggest that they will set their own limit of 20 flights per booster. With this move NASA are setting their limit for crewed reuse at, a not unreasonable, 25% of service life. The remaining 75% of the boosters life will be non crewed flights, and quite possibly finishing with an expendable booster mission.
SD cards have an onboard controller. It knows how big the NAND chip is and the size the SD card is purporting to be. It maps the read and write operations to the right place on the NAND chip. As NAND storage has a limited number of cycles it can change where the data is stored to different places on the chip.
I have come across counterfeit SD cards that have a much smaller NAND chip than the controller asserts to the host. They work just fine till the size of the NAND chip is reached then start overwriting data. It's often quite hard to tell this is happening until something you try to access has been overwritten. Frequently people don't notice for a long time as it takes them quite a while to get their device to over 25% full. I have also seen SD cards that go into a super slow write mode as NAND capacity is approached so they can avoid the overwrite and preserve the lie that they are a lot smaller than they claim.
If the config of the controller (stored on the NAND) gets corrupted if can completely forget where recorded data was stored. Attempts to read the data could all just return the contents of an empty block instead of the blocks where the required data is actually stored.
Normally, but not always. I have once come across a developer who's code passed all the unit tests but failed spectacularly during integration testing which used different test data. Oddly they went off sick just before integration testing commenced. When we pulled the code apart to find out why it was failing it transpired that the unit test cases were built into the code as specific instances. Rather than being a general solution the code only worked with those specific unit test conditions.
> Err you you have any appreciation as to where in space JWST resides?
Yes. The question you need to ask is that a good location for it. The answer is yes if you need to position it where you you need to shade it with a big sun shield to preserve detector cooling capacity, need very low delta-V position keeping (thanks to L2) to preserve fuel. If you predicate the design sufficiently then L2 becomes a good place that rules out maintenance missions so it needs to be maintenance free and run for 10 to 20 years and you get JWST 2.
If on the other hand you design to make use of the changes in access to space the result could be very different. e.g. The Apollo project cost $25bn, equivalent to $175bn (£140bn) today. A return to the moon mission should not carry a $175 billion budget just because that is what it cost then.
And you can't exactly go to the JWST once launched to fix issues (like you could for the Hubble) so it has to work perfectly.
Whilst that was necessary for JWST, it's the first thing that changes on the design of a successor with cheaper and, importantly, more timely access to space. The days when you have to book a launch 3 years away will be gone. There is a lot to be said for something cheaper but maintainable.
The end result should be better too e.g. the detectors can be swapped for better ones as they become available and both coolant and station keeping propellant could be replenished which then permits a greater rate of consumption, hence less exacting design requirements. You can afford to make if stronger/heavier too and save money by not having to manage the tradeoff of additional mass eating up the consumables budget. If a gyro or reaction wheel fails, then replace it. It doesn't need to be designed to limp on for 10 or 20 years.
With all the money saved you can build 2 as the design costs for 1 or 2 are much the same. Why not make a bunch (18) of them each with a big single mirror with the combined cluster benefitting from both more light gathering capacity a bigger baseline. I have no idea if this is feasible, but it demonstrates that the changes to the way we access space might be exploitable to make the JWST successor both better and potentially much cheaper.
It might be worth the price tag. If it had met the initial target to launch in 2007 and a US$1 billion budget it would have been superbly worth it. The issue now is that access to space is getting much much cheaper. It's not impossible to imagine something much more capable being launched in 5-10 years with a budget of less than $1 billion. If that happens sooner rather than later it will devalue JWST.
In some societies its not uncommon for people to conceal that a relative has died so as to continue claiming pensions and other benefits for them.
In places where this is more impossible to do it still needs to be bureaucratically challenging to declare someone "undead". If it's too easy you can steal the identity of a recently departed person and claim their pension for evermore. It's not as if the dead person is going to notice and raise a fuss about it. The crime only tends to get noticed because of the surprising longevity of the pensioner.
In utility scale solar farms they run the cells in strings to get high voltage output. Some as high as 1.5kV though normally less. This saves copper/losses and reduces the number of electronic units needed to export the power. They wouldn't be doing this if it caused severe reliability issues.
The picture shows a 128Mbyte drive on a CP/M machine. Wow. I built mine with a huge 8 inch floppy disk drive that was double density and double sided giving me a massive 1Mbytes of non volatile storage. This made my friend very jealous as he only had a 5 1/4 inch floppy so was limited to 87.5Kbytes, and that normally needed to include the CP/M OS as well as programs and data.
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