Metals are more suitable for selective laser sintering/melting, but I can't fathom how you would combine this with a method where you deposit concrete. I'd expect the concrete to mix with the metal powder and give some sort of unholy porridge-like substance.
reinforced concrete shears wonderfully. nothing to say you can't 3rd print with internal equivalent of rebar caging system, which perhaps also is automatically assembled or perhaps also 3rd formed
You couldn't pre-stress the rebar if you printed it. You could stretch it and print around though, I suppose.
Maybe this is an easier proposition than I thought, but I'm half-way through A Novel and Efficient Synthesis of Cadaverine and it looks like getting anything accomplished in chemistry is much harder than I used to think. The hardest things I know of, like diamond or carbides, look like they have simple molecular structures so are they difficult to simulate or are there more complex substances that are similarly hard bulk materials?
I say bulk because even unobtainium is useless if the stuff falls apart in fractions of a second. Knowledge is nice, but add utility and it's so much better.
well, that should be treated with some pretty harsh legal consequences.
Indeed it should, but I wouldn't hold my breath if I was you. If you really want someone to get slapped down for perjury it helps no end for them to be standing in a court, in front of a judge when they do it.
I know I stand utterly alone in this but Bioshock fucking sucked.
Rest assured you are not alone, though I wouldn't have put it quite so strongly. But then again, I never saw what the big deal was with the original DX either.
What could possibly go wrong and why am I reminded of the old proposal for liquid sodium cooled nuclear reactors in submarines?
It's working out pretty well in Europe, and the Japanese have the advantage of learning from others' mistakes.
As for the submarines I'm not sure; why does underwater cable that's chemically and radiologically benign and miles away from anyone sound as dangerous as a can of irradiated liquid metal that's bad enough before it touches water?
Maybe he's gunning for political office? Being the man who put the lights back on - figuratively speaking - would probably buy a lot of popularity points.
At the risk of burning karma in pointless, off-topic pedantry I will simply point out that our beloved Carl was known for saying "billions and billions", which is four billion at the least.
Still, when we're talking about nearly a trillion dollars what's a factor of two or four between friends, eh?
Interesting, I must read up on that. There's a nuclear station a few miles away from me, on the coast where I don't believe there's a river.
In any event the reason that we're still using heat engines is that the energy coming from reactors is heat. We can't generate electricity directly from neutrons, so there must always be an intermediary. We might replace the working fluid with something other than water (I've heard about mercury being used in the past) but we'll still be putting it in a turbine of some sort.
the problems lie in setting up the system for long term operation, and partly in heat transfer.
This is the part of fusion research that I still don't get. It seems that all the (well-funded) ideas are all looking at an end-game that involves heating water to power a steam generator to produce electricity. Compared to all the technical issues they've been dealing with getting the fusion going, and the potential energy they are talking about generating, it seems somehow short-sighted and inefficient to still be focused on hooking the whole thing up to a bit of 18th century technology that will need a huge fresh water supply to operate.
We've been making steam engines and turbines for a long time now and we've gotten very good at it: take 50% thermodynamic efficiency as a rough starting figure. Direct conversion requires fusion products that are charged particles, which come from only a few potential fuel sources (p+B11 is the most looked-at).
If we go with D+T or other neutron-bearing reactions then I think we'll be stuck with thermal cycles - i.e. steam/gas turbines - simply because there's no other way to extract energy from fast-moving, massive yet uncharged particles. IANANP, so I'd very much like to hear about some new way of getting energy from neutrons.
One more thing, a steam plant doesn't need a large supply of fresh water, as it's a closed cycle. What is needed is a plentiful supply of cold (relatively) water. So long as it doesn't mess up the condensers I don't expect cleanliness/saltiness is a deal-breaker; quantity is more important than quality.
Indeed, but depending on what you're aiming at, 1W of green light may end up being more damaging then 1W of blue light. That said, if we're talking about something that's insensitive to the wavelength - as I now see the OP said - you are of course right.
Mea culpa, I seem to have mixed up drunken moderating with drunken posting!
The energy of a photon is inversely proportional to its wavelength. The green laser may emit more photons per watt, but the photons coming from a blue laser have greater energy.
The sand crawler we all know so well was dirty, weather-worn and perhaps extemporised. In the circumstances methinks they should have gone with a shiny Naboo-inspired design.
Nuclear power as employed now is not truly clean, but doesn't mean it can't be if new reactor designs were built.
The problem with nuclear power as I see it is that if there's ever an accident the response is "Don't build any more power stations!" instead of "Build newer*, safer stations and decommission the old ones."
*i.e. basic designs that aren't older than I am. If you want a car analogy, try this: carburettors could only take the automobile so far; to make progress we had to ditch the whole concept and move to fuel injection. The results were much cleaner and more efficient than the old method could ever have been.
I'd prefer the moon without nuclear contamination, so that there can be a safe moon base there. That doesn't exclude nuclear power, but there is a middle way of safety to choose between "wingnuts/protesters" and carelessness.
Safe?
A moon base will need shielding from cosmic rays, which I know aren't the same as gamma or beta radiation, but it's a start. It'll also need to be airtight - natch - so that ought to take care of alpha radiation and fallout too.
Just what danger does an external nuclear reactor pose to people inside a moon base anyway? Not much, I'd bet, but the reactor might well be inside anyway so the problem of uglying up the lunar landscape is the same as a base using any other means of power generation. Hell, a load of solar panels would do more to spoil the view than anything else.
For my two-penneth, it wouldn't surprise me if we had practical fusion power by the time we had a permanent moon base. I'm not saying we will, just that it's not beyond the realms of possibility.
"The metric system, being decimal, is not well-suited to working with fractions.
Half-metre, quarter-metre, third of a millimetre. It's easy. What you meant - I hope - was that some fractions don't represent an integer number of some smaller measurement. This can happen with imperial measures too; try telling me what one tenth of a foot is.
Officially, you aren't even supposed to say "1/3 meter," but rather "333 millilitres."
Officially? Pah. The only official proscription that would apply here is against a millilitre being a subdivision of a metre. Apart from that there's no reason you can't ask for a half-litre of something, like beer.
For everyday uses, such as cooking, it is much more natural to use fractions.
What's natural depends on your upbringing: I have no problems whatsoever in measuring out 100g of flour or a kilo of mince or anything like that.
Metric units are not always appropriate amounts for convenient use. The 2-liter bottle seems to have become "natural," but if you want to buy a single drink, it's easier to say "a pint" or even "a 12-ounce cup" rather than "400 milliliters." The metric system's rigidity prevents designing units for convenience.
Bull crap. A half-litre of milk is close enough to a traditional* pint as to make no real difference and a standard measure of spirits here has been 25ml since before I was born. No-one asks for 25ml, one just asks for "a measure of X". It's not systemic rigidity that makes things hard, it's your own: if you just accepted a slightly smaller/larger drink as being sufficient then there'd be no trouble at all. For example, our corner shop recently stopped selling pint cartons of milk and started offering 500ml ones instead at a reduced price: no-one really cared. Granted, I get perhaps one cup of coffee-worth less out of them but so what?
These practical issues lead to the use of "folk units" alongside the official metric units, which can lead to conflict when laws are too rigid."
You'll have to forgive me but I've yet to see any practical issues using metric alone or with imperial. The only conflict we've had is when a grocer refused to give prices for metric quantities of produce and started claiming The Man was persecuting him as part of some EU conspiracy when in fact the government had no objection to giving prices per pound so long as there was a price per kilo there as well. It didn't take long for people to see him for the attention-seeking fool he was.
*Refer to what I said about upbringing; simply being traditional adds no objective value to anything.
Slashdot Mirror
Metals are more suitable for selective laser sintering/melting, but I can't fathom how you would combine this with a method where you deposit concrete. I'd expect the concrete to mix with the metal powder and give some sort of unholy porridge-like substance.
reinforced concrete shears wonderfully. nothing to say you can't 3rd print with internal equivalent of rebar caging system, which perhaps also is automatically assembled or perhaps also 3rd formed
You couldn't pre-stress the rebar if you printed it. You could stretch it and print around though, I suppose.
Maybe this is an easier proposition than I thought, but I'm half-way through A Novel and Efficient Synthesis of Cadaverine and it looks like getting anything accomplished in chemistry is much harder than I used to think. The hardest things I know of, like diamond or carbides, look like they have simple molecular structures so are they difficult to simulate or are there more complex substances that are similarly hard bulk materials?
I say bulk because even unobtainium is useless if the stuff falls apart in fractions of a second. Knowledge is nice, but add utility and it's so much better.
well, that should be treated with some pretty harsh legal consequences.
Indeed it should, but I wouldn't hold my breath if I was you. If you really want someone to get slapped down for perjury it helps no end for them to be standing in a court, in front of a judge when they do it.
I know I stand utterly alone in this but Bioshock fucking sucked.
Rest assured you are not alone, though I wouldn't have put it quite so strongly. But then again, I never saw what the big deal was with the original DX either.
I doff my cap.
...damn memory.
What could possibly go wrong and why am I reminded of the old proposal for liquid sodium cooled nuclear reactors in submarines?
It's working out pretty well in Europe, and the Japanese have the advantage of learning from others' mistakes.
As for the submarines I'm not sure; why does underwater cable that's chemically and radiologically benign and miles away from anyone sound as dangerous as a can of irradiated liquid metal that's bad enough before it touches water?
Maybe he's gunning for political office? Being the man who put the lights back on - figuratively speaking - would probably buy a lot of popularity points.
At the risk of burning karma in pointless, off-topic pedantry I will simply point out that our beloved Carl was known for saying "billions and billions", which is four billion at the least.
Still, when we're talking about nearly a trillion dollars what's a factor of two or four between friends, eh?
Indeed! You can say what you like about the Klingons, but at least they never thought about eating us.
Interesting, I must read up on that. There's a nuclear station a few miles away from me, on the coast where I don't believe there's a river.
In any event the reason that we're still using heat engines is that the energy coming from reactors is heat. We can't generate electricity directly from neutrons, so there must always be an intermediary. We might replace the working fluid with something other than water (I've heard about mercury being used in the past) but we'll still be putting it in a turbine of some sort.
the problems lie in setting up the system for long term operation, and partly in heat transfer.
This is the part of fusion research that I still don't get. It seems that all the (well-funded) ideas are all looking at an end-game that involves heating water to power a steam generator to produce electricity. Compared to all the technical issues they've been dealing with getting the fusion going, and the potential energy they are talking about generating, it seems somehow short-sighted and inefficient to still be focused on hooking the whole thing up to a bit of 18th century technology that will need a huge fresh water supply to operate.
We've been making steam engines and turbines for a long time now and we've gotten very good at it: take 50% thermodynamic efficiency as a rough starting figure. Direct conversion requires fusion products that are charged particles, which come from only a few potential fuel sources (p+B11 is the most looked-at).
If we go with D+T or other neutron-bearing reactions then I think we'll be stuck with thermal cycles - i.e. steam/gas turbines - simply because there's no other way to extract energy from fast-moving, massive yet uncharged particles. IANANP, so I'd very much like to hear about some new way of getting energy from neutrons.
One more thing, a steam plant doesn't need a large supply of fresh water, as it's a closed cycle. What is needed is a plentiful supply of cold (relatively) water. So long as it doesn't mess up the condensers I don't expect cleanliness/saltiness is a deal-breaker; quantity is more important than quality.
Indeed, but depending on what you're aiming at, 1W of green light may end up being more damaging then 1W of blue light. That said, if we're talking about something that's insensitive to the wavelength - as I now see the OP said - you are of course right.
Mea culpa, I seem to have mixed up drunken moderating with drunken posting!
No, per photon.
The energy of a photon is inversely proportional to its wavelength. The green laser may emit more photons per watt, but the photons coming from a blue laser have greater energy.
You talking about Mark Hamill's face or the Sand Crawler?
Yes.
I guess you haven't seen the enhancements in the new Blu-Ray version.
Your point? If anything it would have been worse, being able to see every pock mark, burn and blemish in glorious (TM) high-definition.
You want to see a monstrosity? There aren't any near me, but this comes pretty close.
We call it the slug.
The sand crawler we all know so well was dirty, weather-worn and perhaps extemporised. In the circumstances methinks they should have gone with a shiny Naboo-inspired design.
Well, actually saying that it requires a sufficiently fast disk would be a good start.
Honesty about the limitations of your products is a big incentive to me, but I'm odd that way.
Here's a rule of thumb I've found useful: whenever an ad says "up to" you need to replace it with "usually less than".
Not for trying to get money for the people you represent, but for calling people idiots and expecting them to open their wallets.
Nuclear power as employed now is not truly clean, but doesn't mean it can't be if new reactor designs were built.
The problem with nuclear power as I see it is that if there's ever an accident the response is "Don't build any more power stations!" instead of "Build newer*, safer stations and decommission the old ones."
*i.e. basic designs that aren't older than I am. If you want a car analogy, try this: carburettors could only take the automobile so far; to make progress we had to ditch the whole concept and move to fuel injection. The results were much cleaner and more efficient than the old method could ever have been.
I'd prefer the moon without nuclear contamination, so that there can be a safe moon base there. That doesn't exclude nuclear power, but there is a middle way of safety to choose between "wingnuts/protesters" and carelessness.
Safe?
A moon base will need shielding from cosmic rays, which I know aren't the same as gamma or beta radiation, but it's a start. It'll also need to be airtight - natch - so that ought to take care of alpha radiation and fallout too.
Just what danger does an external nuclear reactor pose to people inside a moon base anyway? Not much, I'd bet, but the reactor might well be inside anyway so the problem of uglying up the lunar landscape is the same as a base using any other means of power generation. Hell, a load of solar panels would do more to spoil the view than anything else.
For my two-penneth, it wouldn't surprise me if we had practical fusion power by the time we had a permanent moon base. I'm not saying we will, just that it's not beyond the realms of possibility.
"The metric system, being decimal, is not well-suited to working with fractions.
Half-metre, quarter-metre, third of a millimetre. It's easy. What you meant - I hope - was that some fractions don't represent an integer number of some smaller measurement. This can happen with imperial measures too; try telling me what one tenth of a foot is.
Officially, you aren't even supposed to say "1/3 meter," but rather "333 millilitres."
Officially? Pah. The only official proscription that would apply here is against a millilitre being a subdivision of a metre. Apart from that there's no reason you can't ask for a half-litre of something, like beer.
For everyday uses, such as cooking, it is much more natural to use fractions.
What's natural depends on your upbringing: I have no problems whatsoever in measuring out 100g of flour or a kilo of mince or anything like that.
Metric units are not always appropriate amounts for convenient use. The 2-liter bottle seems to have become "natural," but if you want to buy a single drink, it's easier to say "a pint" or even "a 12-ounce cup" rather than "400 milliliters." The metric system's rigidity prevents designing units for convenience.
Bull crap. A half-litre of milk is close enough to a traditional* pint as to make no real difference and a standard measure of spirits here has been 25ml since before I was born. No-one asks for 25ml, one just asks for "a measure of X". It's not systemic rigidity that makes things hard, it's your own: if you just accepted a slightly smaller/larger drink as being sufficient then there'd be no trouble at all. For example, our corner shop recently stopped selling pint cartons of milk and started offering 500ml ones instead at a reduced price: no-one really cared. Granted, I get perhaps one cup of coffee-worth less out of them but so what?
These practical issues lead to the use of "folk units" alongside the official metric units, which can lead to conflict when laws are too rigid."
You'll have to forgive me but I've yet to see any practical issues using metric alone or with imperial. The only conflict we've had is when a grocer refused to give prices for metric quantities of produce and started claiming The Man was persecuting him as part of some EU conspiracy when in fact the government had no objection to giving prices per pound so long as there was a price per kilo there as well. It didn't take long for people to see him for the attention-seeking fool he was.
*Refer to what I said about upbringing; simply being traditional adds no objective value to anything.
I don't know about genius, but at least he could spell.
I suggest you buy a new Mac; the iOS-style spellchecker really comes in handy despite occasionally mangling perfectly corpulent words.