I'm guessing you never disassembled one to see how it actually worked. I did. Go ahead and find an exemplar and give it a go.
OK, here is the schematic of the most widely used mechanical telephone in The Netherlands: the T65. When the telephone is on hook ("hoorn"), only the ringer (bel) is connected to the line. I really cannot think of another arrangement: the ringer voltage is high (100V?) so you don't want that appearing over your mic or speaker. Please share with us the schematic of the phones you disassembled, or are you really a troll?
Explaining it to the manufacturers of 900 kV stun guns will have no effect. They know very well that their product does not reach 900 kV. Those tasers may very well reach 90-100 kV (spark length of 3-3,5 cm), but not tenfold that. It's just as with the 200W PMPO computer speaker sets that are supplied from a 12W transformer: pure marketing hype.
But, I agree with your main point: it is trivial to create a sufficiently high voltage in a small volume. Even the simplest 2 kV fly swatter tennis rackets show that.
I built a stun gun capable of generating 900,000 volts on-demand out of a few dollars worth of parts and a 9 volt battery, and it fits in the palm of your hand
900V or 9 kV I would believe, 900 kV not so much. You would need creeping distances of more than 300 mm just to prevent arcing and making the voltage collapse before it even reached the 900 kV. "900 kV" and "fits into the palm of your hand" are mutually exclusive, I think. (and yes, I've designed and built multi-kV devices myself)
Ah, the second link made things clear. If you just compress air without adding water, it heats up. This heat is lost over time, lowering efficiency. When you spray in water, you take this heat loss up front, that is: if you don't re-use the heat in the water. The brilliant thing LightSail Energy is doing is that they re-use the heat in the water on expansion. And because the heat capacity of water is much higher than that of air, relatively little water is needed.
If you would just release the heat in the water to the environment (which I thought was what happened when you described the cooling step), efficiency would be lower than without the cooling step.
I just drank half a liter from a can marked "Beer". Paid 50 (Euro) cents for it. I'm from The Netherlands, where - the article tells me - beer is 2.48 (dollars) for half a lier. Something doesn't add up here. An average beer may be more expensive here, but five times? come on...
There are a few silver nanoparticle inkjet inks on the market with very low resistance. ~0.2 ohm per square for water based and even lower for solvent based inks.
I wouldn't call 0.2 ohm per square low resistance. If I would print a trace of 10 mils width with a length of just one inch (1000 mils) with the ink you mention, it would have a resistance of 20 ohms. This system must have far lower resistance to be useful.
I still don't understand what you mean. Vastly more water will be produced when burning gasoline than the carbon monoxide and nitreous compunds that you mention. The main constituents of exhaust gases are carbon dioxide and water. Compression ratio will not change that.
Automobiles produce carbon monoxide, various nitreous compounds, and minimal water.
HUH??? Automobiles burn mainly alkanes, which are composed of carbon and hydrogen. When you burn those, you get carbon dioxide and water. So why you claim that automobiles produce minimal water is a mystery to me. Most water that is produced will be in vapour form, so you don't see it, but it's there, nevertheless.
Voltage drop across a white LED is 3-4 V. Who ever heard of germanium LEDs with 0.8V drop? And if you have a power LED used for lighting, you don't use a resistor to limit the current; you use a small switchmode power supply. If you design a good one, you can have electrical efficiency of >90% running from 12V, wasting less than 10%.
LHCb sees where the antimatter's gone ALICE looks at collisions of lead ions CMS and ATLAS are two of a kind They're looking for whatever new particles they can find The LHC accelerates the protons and the lead And the things that it discovers will rock you in the head.
Whatever it is, I got a prompt saying that an extension that I want to use would be disabled if I upgraded to 8.
Would it be disabled because it is incompatible, or because you did not install it yourself? In the latter case, you can just enable the checkmark before it, and continue using it. Many programs install, if you don't pay attention, extensions that you may not be totally happy with ('Ask'-toolbar, anyone?) Firefox now disables these by default, but gives you the option to keep them enabled if you want them. I find this a useful feature. On the other hand, there may be extensions that refuse to load after a major version number change, That is a pain, but in many cases, this will be remedied quickly.
In Suriname / Dutch slang, "doekoe" (pronounced as "duku") means money. So, what would be the ultimate purpose of "Duqu"? To make heaps of money with it!
Hey, yours is the second one I heard of! A friend of mine made one too for his car. Took a standard cradle, which has just about the right size, and mounted it over the double-din car stereo slot. He had one problem, if I remember correctly. When you put the Droid tablet into the cradle, I think you could either charge, or have sound output, or something like that. Stupid limitation by Samsung who had not foreseen creative uses of their product. I don't think it took him a week to make, however.
A claim like this requires some explanation of how it could be done, and such an explanation is obviously missing from the article. You shouldn't try to make up explanations for them (although that is how this nonsense continues to thrive).
Or to put it another way, if this thing can go through the point where it is going at the speed of the wind to then go faster than the wind the, assuming that it isn't storing energy from some time in the past and that the wind doesn't slow down, then it could also sit in zero mph wind and start going forward all by itself, just powered by a zero mph (non-existent) wind. Perhaps you believe that. I don't.
Parent has been moderated "Troll" but I think he is sincere. And, at first, I did not believe this to be possible either. I now understand how it works.
The propellor is used as a sail. As long as there is pressue on the back of the 'sail' it can accelerate the cart. If the sail were fixed w.r.t. the cart, it would stop receiving back pressure as soon as you reach wind speed. When you pass wind speed, you would get wind pressure from the front, and you would slow down. So, what do they do: they drive the propellor from the wheels, so the surface of the propellor gets a forward speed that is lower than the forward speed of the cart itself. In that way, even when the cart itself has passed wind speed, the surface of the propellor hasn't, and the wind can keep pushing the propellor forward, and thus, the cart. The cart itself will feel the wind coming from the front, but the surface of the propellor, because it is turning, will still feel the wind force from the back.
Then a last question remains: will this force on the back of the propellor be greater than the force in the opposite direction on the wheels (that causes the turning of the propellor)? This depends on the gear ratio. If you choose the gear ratio 'wrong' you will create a cart that will propel itself against the wind instead of along with it. Notice that this is something that has been done earlier many times.
If it would be stationary, it would get close to wind speed, but never be able to pass it. But the propellor is being driven by the wheels. This gives the surface of the propellor blades a speed forward (wrt the ground) that is lower than the wind speed, even when the cart itself is already above wind speed. In this way, the wind can still exert a forward force on the blades, and thus propel the cart.
That would make the total energy 30 kW * 4 h = 120 kW * h, not 120 kW / h. The units are multiplied / divided the same way as the numbers. If you would have a power that was linearly increasing from zero to 30 kW in 15 minutes, then you would have an increase of 30 kW / 0.25h, or 120 kW/h. As you see, the unit kilowatt per hour is rarely encountered. When you speak of energy, you have kilowatthours, not kilowatts per hour.
Normally I wouldn't mind so much, but further down in the thread, people are quoting your GW number, and basing their conclusions on it. And I think your physics prof would take more offence from the nonsensical kilowatt-per-hour (that's a factor of hours squared off!) than from the capitalization;-) Anyway, in the end you are right, more than a megawatt _is_ a lot of power.
say a car would need 30kw to maintain motorway speed (say 50, for ease of calculation), and ranges 200 miles, that means you need 120 KW/h of stored energy, pack 90% of that in five minutes, and you end up with roughly 1.3 Gigawatt of drain sustained over 5 minutes...
IT'S OVER 1.21 GIGAWAT!! (yeah i know, i got my meme's mixed)
That would be 30 kW (not kw), 120 kWh (not KW/h), 1.3 MW (not GW) So no, it's not over 1.21 gigawatt, just a factor 997 lower...;-)
I cannot find anywhere how this system interconnects the components. They write about the issues of current technology (solder containing lead, chemicals for etching PCB boards), but don't give an insight how their technology works around these problems. Encasing your whole device in plastic is neat, but the components will still have to be interconnected. How? I cannot find it in the article, nor on the site of Griffith University.
To pick one more nit: I wasn't correct myself when writing the equations. It should be Ic = Is ( exp(Vbe/Vth) - 1 ) In practice, Is is so small that you will not see the difference except for very small collector currents, but it's just bad style to correct errors of others when you are not correct yourself;-)
I really like the simplicity of the circuit, and the way they try to explain the basics of transistor design. Nowadays, there is an integrated circuit for about anything, but just using that doesn't make you learn anything, and - in my opinion - takes away the fun of creating something from scratch.
But am I the only one to see the huge error in the equations they are using? They state Ic = Ib * beta Ib = Is exp(Vbe/Vth) where it should be Ic = Is exp(Vbe/Vth) Ib = Ic / beta or, their equations are off by a factor of beta! That does not seem too important, it appears you could compensate for this in Is, but in practice, that is not so straightforward. The exponential relation between Ic and Vbe holds over many decades, whereas beta is not nearly as constant as we sould like. So, if these are really MIT students, I'd like a word with their professors...;-)
I know I'm being a pedant here, but there ain't no plug and play if you're using a _serial cable_.
You'd be surprised. Last week, I visited a customer using one of our old stability measurement platforms. That device is equipped with a 9-pin serial cable. It would not work. The reason? Windows 98, helpful as ever, had detected it as a serial mouse, and installed the appropriate driver, after which our program could not open the COM-port any more. This surely was an attempt at plug and play. In practice, it was more like plug and pray. Oh no, plug and swear...
I'm not so famailar with Microsoft's signing approach. I only know it for drivers, and there it means: driver is signed -> ok, driver is not signed -> use at your own risk. No fine-grained control at all. Nokia's approach is fine-grained, just like yours. If you have a signature to use the GPS module, you can use that, but not access the contacts list. The difference with your approach is that it _requires_ a signature to access a specific capability, whereas your approach leaves this up to the wisdom of the user.
Slashdot Mirror
That's what I expected. ;-)
My post was mainly intended for people who might believe his claims.
For them, maybe, facts would be helpful
I'm guessing you never disassembled one to see how it actually worked. I did. Go ahead and find an exemplar and give it a go.
OK, here is the schematic of the most widely used mechanical telephone in The Netherlands: the T65.
When the telephone is on hook ("hoorn"), only the ringer (bel) is connected to the line.
I really cannot think of another arrangement: the ringer voltage is high (100V?) so you don't want that appearing over your mic or speaker.
Please share with us the schematic of the phones you disassembled, or are you really a troll?
Explaining it to the manufacturers of 900 kV stun guns will have no effect.
They know very well that their product does not reach 900 kV.
Those tasers may very well reach 90-100 kV (spark length of 3-3,5 cm), but not tenfold that.
It's just as with the 200W PMPO computer speaker sets that are supplied from a 12W transformer: pure marketing hype.
But, I agree with your main point: it is trivial to create a sufficiently high voltage in a small volume.
Even the simplest 2 kV fly swatter tennis rackets show that.
I built a stun gun capable of generating 900,000 volts on-demand out of a few dollars worth of parts and a 9 volt battery, and it fits in the palm of your hand
900V or 9 kV I would believe, 900 kV not so much.
You would need creeping distances of more than 300 mm just to prevent arcing and making the voltage collapse before it even reached the 900 kV.
"900 kV" and "fits into the palm of your hand" are mutually exclusive, I think.
(and yes, I've designed and built multi-kV devices myself)
Ah, the second link made things clear.
If you just compress air without adding water, it heats up.
This heat is lost over time, lowering efficiency.
When you spray in water, you take this heat loss up front, that is: if you don't re-use the heat in the water.
The brilliant thing LightSail Energy is doing is that they re-use the heat in the water on expansion.
And because the heat capacity of water is much higher than that of air, relatively little water is needed.
If you would just release the heat in the water to the environment (which I thought was what happened when you described the cooling step), efficiency would be lower than without the cooling step.
This is no workaround.
When you absorb the heat in water it is still lost. The only effect is that the temperature will be lower.
I just drank half a liter from a can marked "Beer". Paid 50 (Euro) cents for it. I'm from The Netherlands, where - the article tells me - beer is 2.48 (dollars) for half a lier. Something doesn't add up here. An average beer may be more expensive here, but five times? come on...
There are a few silver nanoparticle inkjet inks on the market with very low resistance. ~0.2 ohm per square for water based and even lower for solvent based inks.
I wouldn't call 0.2 ohm per square low resistance.
If I would print a trace of 10 mils width with a length of just one inch (1000 mils) with the ink you mention, it would have a resistance of 20 ohms.
This system must have far lower resistance to be useful.
I still don't understand what you mean.
Vastly more water will be produced when burning gasoline than the carbon monoxide and nitreous compunds that you mention.
The main constituents of exhaust gases are carbon dioxide and water.
Compression ratio will not change that.
Automobiles produce carbon monoxide, various nitreous compounds, and minimal water.
HUH??? Automobiles burn mainly alkanes, which are composed of carbon and hydrogen.
When you burn those, you get carbon dioxide and water.
So why you claim that automobiles produce minimal water is a mystery to me.
Most water that is produced will be in vapour form, so you don't see it, but it's there, nevertheless.
Voltage drop across a white LED is 3-4 V. Who ever heard of germanium LEDs with 0.8V drop?
And if you have a power LED used for lighting, you don't use a resistor to limit the current; you use a small switchmode power supply.
If you design a good one, you can have electrical efficiency of >90% running from 12V, wasting less than 10%.
Ok, here we go again:
LHCb sees where the antimatter's gone
ALICE looks at collisions of lead ions
CMS and ATLAS are two of a kind
They're looking for whatever new particles they can find
The LHC accelerates the protons and the lead
And the things that it discovers will rock you in the head.
Or, for the full version: http://www.youtube.com/watch?v=j50ZssEojtM
Whatever it is, I got a prompt saying that an extension that I want to use would be disabled if I upgraded to 8.
Would it be disabled because it is incompatible, or because you did not install it yourself?
In the latter case, you can just enable the checkmark before it, and continue using it.
Many programs install, if you don't pay attention, extensions that you may not be totally happy with ('Ask'-toolbar, anyone?)
Firefox now disables these by default, but gives you the option to keep them enabled if you want them.
I find this a useful feature.
On the other hand, there may be extensions that refuse to load after a major version number change, That is a pain, but in many cases, this will be remedied quickly.
In Suriname / Dutch slang, "doekoe" (pronounced as "duku") means money.
So, what would be the ultimate purpose of "Duqu"?
To make heaps of money with it!
A double din android car stereo
Hey, yours is the second one I heard of!
A friend of mine made one too for his car.
Took a standard cradle, which has just about the right size, and mounted it over the double-din car stereo slot.
He had one problem, if I remember correctly.
When you put the Droid tablet into the cradle, I think you could either charge, or have sound output, or something like that.
Stupid limitation by Samsung who had not foreseen creative uses of their product.
I don't think it took him a week to make, however.
You forgot the "GET OFF MY LAWN" part... *sigh*
Hey, that's implied by my low UID. It shouldn't have to be explcit.
If your UID really would be low, then OK, maybe.
But to be considered 'low', I would guess that it would have 4 digits. Or less.
A claim like this requires some explanation of how it could be done, and such an explanation is obviously missing from the article. You shouldn't try to make up explanations for them (although that is how this nonsense continues to thrive).
Or to put it another way, if this thing can go through the point where it is going at the speed of the wind to then go faster than the wind the, assuming that it isn't storing energy from some time in the past and that the wind doesn't slow down, then it could also sit in zero mph wind and start going forward all by itself, just powered by a zero mph (non-existent) wind. Perhaps you believe that. I don't.
Parent has been moderated "Troll" but I think he is sincere.
And, at first, I did not believe this to be possible either.
I now understand how it works.
The propellor is used as a sail.
As long as there is pressue on the back of the 'sail' it can accelerate the cart.
If the sail were fixed w.r.t. the cart, it would stop receiving back pressure as soon as you reach wind speed. When you pass wind speed, you would get wind pressure from the front, and you would slow down.
So, what do they do: they drive the propellor from the wheels, so the surface of the propellor gets a forward speed that is lower than the forward speed of the cart itself.
In that way, even when the cart itself has passed wind speed, the surface of the propellor hasn't, and the wind can keep pushing the propellor forward, and thus, the cart.
The cart itself will feel the wind coming from the front, but the surface of the propellor, because it is turning, will still feel the wind force from the back.
Then a last question remains: will this force on the back of the propellor be greater than the force in the opposite direction on the wheels (that causes the turning of the propellor)?
This depends on the gear ratio. If you choose the gear ratio 'wrong' you will create a cart that will propel itself against the wind instead of along with it.
Notice that this is something that has been done earlier many times.
If it would be stationary, it would get close to wind speed, but never be able to pass it.
But the propellor is being driven by the wheels.
This gives the surface of the propellor blades a speed forward (wrt the ground) that is lower than the wind speed, even when the cart itself is already above wind speed.
In this way, the wind can still exert a forward force on the blades, and thus propel the cart.
That would make the total energy 30 kW * 4 h = 120 kW * h, not 120 kW / h.
The units are multiplied / divided the same way as the numbers.
If you would have a power that was linearly increasing from zero to 30 kW in 15 minutes, then you would have an increase of 30 kW / 0.25h, or 120 kW/h.
As you see, the unit kilowatt per hour is rarely encountered.
When you speak of energy, you have kilowatthours, not kilowatts per hour.
Normally I wouldn't mind so much, but further down in the thread, people are quoting your GW number, and basing their conclusions on it. ;-)
And I think your physics prof would take more offence from the nonsensical kilowatt-per-hour (that's a factor of hours squared off!) than from the capitalization
Anyway, in the end you are right, more than a megawatt _is_ a lot of power.
say a car would need 30kw to maintain motorway speed (say 50, for ease of calculation), and ranges 200 miles, that means you need 120 KW/h of stored energy, pack 90% of that in five minutes, and you end up with roughly 1.3 Gigawatt of drain sustained over 5 minutes...
IT'S OVER 1.21 GIGAWAT!! (yeah i know, i got my meme's mixed)
That would be 30 kW (not kw), 120 kWh (not KW/h), 1.3 MW (not GW) ;-)
So no, it's not over 1.21 gigawatt, just a factor 997 lower...
I cannot find anywhere how this system interconnects the components.
They write about the issues of current technology (solder containing lead, chemicals for etching PCB boards), but don't give an insight how their technology works around these problems. Encasing your whole device in plastic is neat, but the components will still have to be interconnected.
How? I cannot find it in the article, nor on the site of Griffith University.
To pick one more nit: ;-)
I wasn't correct myself when writing the equations.
It should be
Ic = Is ( exp(Vbe/Vth) - 1 )
In practice, Is is so small that you will not see the difference except for very small collector currents, but it's just bad style to correct errors of others when you are not correct yourself
I really like the simplicity of the circuit, and the way they try to explain the basics of transistor design. Nowadays, there is an integrated circuit for about anything, but just using that doesn't make you learn anything, and - in my opinion - takes away the fun of creating something from scratch.
But am I the only one to see the huge error in the equations they are using? ;-)
They state
Ic = Ib * beta
Ib = Is exp(Vbe/Vth)
where it should be
Ic = Is exp(Vbe/Vth)
Ib = Ic / beta
or, their equations are off by a factor of beta!
That does not seem too important, it appears you could compensate for this in Is, but in practice, that is not so straightforward.
The exponential relation between Ic and Vbe holds over many decades, whereas beta is not nearly as constant as we sould like.
So, if these are really MIT students, I'd like a word with their professors...
I know I'm being a pedant here, but there ain't no plug and play if you're using a _serial cable_.
You'd be surprised.
Last week, I visited a customer using one of our old stability measurement platforms.
That device is equipped with a 9-pin serial cable.
It would not work.
The reason? Windows 98, helpful as ever, had detected it as a serial mouse, and installed the appropriate driver, after which our program could not open the COM-port any more.
This surely was an attempt at plug and play.
In practice, it was more like plug and pray.
Oh no, plug and swear...
I'm not so famailar with Microsoft's signing approach. I only know it for drivers, and there it means: driver is signed -> ok, driver is not signed -> use at your own risk.
No fine-grained control at all.
Nokia's approach is fine-grained, just like yours.
If you have a signature to use the GPS module, you can use that, but not access the contacts list.
The difference with your approach is that it _requires_ a signature to access a specific capability, whereas your approach leaves this up to the wisdom of the user.
But, if I'm wrong, please correct me!