Being near high tension lines tend to cause interference in radio signals. More static, etc. This has almost zero resistance. So, does that mean less interference?
No. The transmission line will still radiate an AC electromagnetic field at 60Hz, but the cable housing around it may prevent that from creating interference.
In addition, by putting "receivers" close to high-tension lines, you can take energy from it. What is interesting is that it causes local heating on the lines. So, can somebody use some copper coils to do the same to these? If so, then it could be used to increase local heat to the point of causing a cascade loss; i.e. here is a way to bring down a line, and causes a massive release of energy. Is this true?
An external field can induce current in the superconducting line but that won't cause heating because the line has no resistance. Superconductors can lose their superconductivity in the presence of a magnetic field so I suppose it is possible to bring the line down in a way similar to the one you describe.
So, no voltage implies no resistance implies superconductivity. But the reverse isn't true? We have a cable that has superconductivity yet still has voltage?
There is a potential difference between the cable and ground because the cable is insulated from ground, ie, there is no superconductor to ground.
There is no potential difference along the cable because it has no resistance.
(Solar heaters are so efficient, they're even used in Wales, not a country known for masses of sunlight.)
I used to have a solar water heater in Melbourne at 37 degrees south. In the winter it would deliver warm water at best. In the winter in the UK I doubt it would be any good at all.
Lastly, there's one small issue I have with these superconducting cables. 77K? There are superconductors that operate at something like 2-2.5 times that temperature! Are these guys wanting to prove it can't be done?
High temperature superconductors tend to lose their conductivity in the presence of a magnetic field, which limits their current handling ability. Also the materials are quite brittle.
In a standard copper line the value is zero: we don't cool them
Conventional underground transmission lines are oil cooled. Superconducting transmission lines have almost zero resistance and should require less cooling once they reach working temperature.
While I think BestBuy should be congratulated for putting Ubuntu in stores, even if they are charging $20 for it (wayyyy cheap compared to Windows Vista or XP). I predict it will not go well for them,
Its a bit like that website where you could buy a copy of firefox. It is cheap to maintain and it gets a few customers. It probably doesn't cost much for Best Buy to stock boxes of Ubuntu, and a few people will buy it, even if by accident.
Okay but now I know to look out for people running truecrypt and to ask to see their encrypted volume (rubber hose held behind back at that point) so they show me their partly used 800mb encrypted volume, I image it and start a dictionary attack to get the rest of the info.
I prefer the skyhook. The idea is to launch a cable about 1000 km long into orbit then spin it up so that it rolls along its orbit. At the lowest point one end of the cable is inside the atmosphere almost stationary relative to the ground. The other end of the cable is 1000 km higher and moving above escape velocity.
This system could easily exchange mass between any two planetary surfaces in the solar system for a much smaller cost than chemical rockets. Of course for every kilo of food you send to Mars you need to send a kilo of Martian rock back.
Seriously, if you had the chance to put an eight million ton starship in orbit in exchange for one random death, would you say no? The chance to set up a self-sustaining moonbase in one move? To visit the entire solar system in short order?
Seriously, if you had the chance to put an eight million ton starship in orbit in exchange for one random death, would you say no? The chance to set up a self-sustaining moonbase in one move? To visit the entire solar system in short order?
We could do that now if we wanted to. It would be expensive but so would be building an Orion.
As for how: consider using ion thrusters and small fission reactors.
I don't care *what* the video is made of really. I just really want video with my space stories. When something launches, when something crashes, when something oh, lands on Mars or something... I want video. I don't care if it is computer generated,
Take it easy Son. I had to walk 50 kilometers uphill in the snow to watch Neil Armstrong take that first step.
wasted millions of dollars developing a questionable gadget that no one asked for--the Foleo
I might have bought a Foleo but now I have an eeePC, which was a huge hit for Asus. Some of the specifics like the tie in to the Treo were a bad idea, but the hardware platform might have taken off if they had persisted with it.
I'm in Australia. It gave me a video advertisement for some PVC pipe company in the US. What a waste of bandwidth. If they want to advertise they should target them.
They should be looking at external combustion, like the waverider, for hypersonic engines. Far better to ignite the shockwave than to try to move the shockwave into the engine.
Alternatively they should just build a rocket and be done with it. A COTS launcher with a heat shield on the front would do the job nicely.
Slashdot Mirror
Being near high tension lines tend to cause interference in radio signals. More static, etc. This has almost zero resistance. So, does that mean less interference?
No. The transmission line will still radiate an AC electromagnetic field at 60Hz, but the cable housing around it may prevent that from creating interference.
In addition, by putting "receivers" close to high-tension lines, you can take energy from it. What is interesting is that it causes local heating on the lines. So, can somebody use some copper coils to do the same to these? If so, then it could be used to increase local heat to the point of causing a cascade loss; i.e. here is a way to bring down a line, and causes a massive release of energy. Is this true?
An external field can induce current in the superconducting line but that won't cause heating because the line has no resistance. Superconductors can lose their superconductivity in the presence of a magnetic field so I suppose it is possible to bring the line down in a way similar to the one you describe.
So, no voltage implies no resistance implies superconductivity. But the reverse isn't true? We have a cable that has superconductivity yet still has voltage?
There is a potential difference between the cable and ground because the cable is insulated from ground, ie, there is no superconductor to ground.
There is no potential difference along the cable because it has no resistance.
(Solar heaters are so efficient, they're even used in Wales, not a country known for masses of sunlight.)
I used to have a solar water heater in Melbourne at 37 degrees south. In the winter it would deliver warm water at best. In the winter in the UK I doubt it would be any good at all.
Lastly, there's one small issue I have with these superconducting cables. 77K? There are superconductors that operate at something like 2-2.5 times that temperature! Are these guys wanting to prove it can't be done?
High temperature superconductors tend to lose their conductivity in the presence of a magnetic field, which limits their current handling ability. Also the materials are quite brittle.
In a standard copper line the value is zero: we don't cool them
Conventional underground transmission lines are oil cooled. Superconducting transmission lines have almost zero resistance and should require less cooling once they reach working temperature.
wtf? I thought you weren't allowed to actually "sell" Ubuntu for money? (Besides, of course, ordering the cd from Ubuntu for like $1)
Break out the beer folks, this one's gotta be good.
Absolutely nothing in the GPL states that you couldn't sell it (as long as you include the source code).
But are they?
While I think BestBuy should be congratulated for putting Ubuntu in stores, even if they are charging $20 for it (wayyyy cheap compared to Windows Vista or XP). I predict it will not go well for them,
Its a bit like that website where you could buy a copy of firefox. It is cheap to maintain and it gets a few customers. It probably doesn't cost much for Best Buy to stock boxes of Ubuntu, and a few people will buy it, even if by accident.
But are Best Buy offering to supply the source code? They have to do that if they distribute GPL software.
Lets have a BSD article for every bug in lex and yacc.
You up reading Slashdot at this hour.
9:50 PM?
Its really the NSA I am talking about.
Okay but now I know to look out for people running truecrypt and to ask to see their encrypted volume (rubber hose held behind back at that point) so they show me their partly used 800mb encrypted volume, I image it and start a dictionary attack to get the rest of the info.
I prefer the skyhook. The idea is to launch a cable about 1000 km long into orbit then spin it up so that it rolls along its orbit. At the lowest point one end of the cable is inside the atmosphere almost stationary relative to the ground. The other end of the cable is 1000 km higher and moving above escape velocity.
This system could easily exchange mass between any two planetary surfaces in the solar system for a much smaller cost than chemical rockets. Of course for every kilo of food you send to Mars you need to send a kilo of Martian rock back.
So you're expecting the Martians to tag all the cameras and then tip over the probe soonish?
In three months time the probe will be underneath the north polar ice cap and the mission will be over. Additionally the TEGA instrument has developed a wiring fault and may become totally unusable soon.
Not everyone is as worked up over Phoenix as you seem to be.
I agree. This whole space exploration thing has become quite passe.
Personally I find it strange that a member of the Mars Phoenix team left the project while the vehicle was still operating on Mars, and that the most of the team are taking the July 4 holiday off as if Phoenix will still be there in a years time.
Seriously, if you had the chance to put an eight million ton starship in orbit in exchange for one random death, would you say no? The chance to set up a self-sustaining moonbase in one move? To visit the entire solar system in short order?
Yes, but what if it was your death?
Thats why I suggested an alternative to Orion.
Its what America does best:
Music
Microcode
High speed pizza delivery
Seriously, if you had the chance to put an eight million ton starship in orbit in exchange for one random death, would you say no? The chance to set up a self-sustaining moonbase in one move? To visit the entire solar system in short order?
We could do that now if we wanted to. It would be expensive but so would be building an Orion.
As for how: consider using ion thrusters and small fission reactors.
just imagine the environmentalists' reaction to something that uses nuclear bombs as propulsion.
And what would your reaction be if they launched the thing within 10000km of your home?
I don't care *what* the video is made of really. I just really want video with my space stories. When something launches, when something crashes, when something oh, lands on Mars or something... I want video. I don't care if it is computer generated,
Take it easy Son. I had to walk 50 kilometers uphill in the snow to watch Neil Armstrong take that first step.
Elephants have been rather underrepresented in space recently.
I hope you are right.
wasted millions of dollars developing a questionable gadget that no one asked for--the Foleo
I might have bought a Foleo but now I have an eeePC, which was a huge hit for Asus. Some of the specifics like the tie in to the Treo were a bad idea, but the hardware platform might have taken off if they had persisted with it.
I'm in Australia. It gave me a video advertisement for some PVC pipe company in the US. What a waste of bandwidth. If they want to advertise they should target them.
The shuttle goes around the Earth in one and a half hours. I don't think this aircraft could carry enough fuel to operate for one and a half minutes.
They should be looking at external combustion, like the waverider, for hypersonic engines. Far better to ignite the shockwave than to try to move the shockwave into the engine.
Alternatively they should just build a rocket and be done with it. A COTS launcher with a heat shield on the front would do the job nicely.
the only thing cooler would be a functioning Orion spacecraft.
Ah yes, old bang bang. I recommend we leave the plans on file until we get attacked by aliens.