I imagine you would need quite a large volume of helium to lift something like that.
Did you ever try to hang something to that helium baloon you got for free at the fair? It can lift a piece of paper and not much more.
Check this flying saucer. This big bag of helium can lift only a small battery, receiver and an electric motor. Strap a PDA to it, and you would probably need twice the volume.
I guess you could do better if you used hydrogen, but then I don't think anyone would be confortable with a big bag of explosive gas automaticaly following him.
Be carefull if you are using a reflector-type telescope - one with the mirror (for example Newton reflector). These kind of telescopes should never be pointed towards the sun - whether you are looking through the eyepiece or only projecting a picture of the sun to a screen.
Because the mirror focuses the light, the lenses in the eyepiece can get very hot and can deform or even shatter.
Better stay with binoculars. You can even use two pieces of paper. One black with a tiny hole and another one white to use as a screen.
You don't have to be subjected to 30 second commercials before the previews and the movie.
No... But instead you are subjected to five 30 second FBI warnings in five different languages (and your player won't let you skip them).
I have also seen a number of rented DVDs that include trailers for "comming soon" movies that are played before the movie and you also can't skip through them.
Inertia exerts stresses on different points of the structure than gravity does. Take for example the arm of the space shuttle. It can move huge loads in and out of the shuttle's cargo bay while it is in orbit , but it can't even lift itself when the shuttle is on the ground
I doubt that these android robots can even stand upright on the surface of any planet. If they were designed for operation in zero gravity their framework is probably to weak to support the full weight.
The article does not mention that, but I think these robots will be remotely controlled from the earth. This is the simplest way to do it in earth orbit. Why bother with a complicated computer intelligence, when you can use a human operator? Of course, this wouldn't work for mars because of the time lag.
Also I wonder what kind of a power supply do they use? If they are really the size of a man, they don't have plenty of room for bulky fuel cells, which means that their autonomous time must be pretty short.
This is not working if you have all the latest security fixes installed.
Need to Convince Mom and Dad?
on
TI-84 Plus Released
·
· Score: 3, Insightful
Am I the only one that is disgusted by all these "Need to Convince Mom and Dad?" buttons (see bottom left) that are popping up everywhere?
I mean, how long before companies begin to advise children to cry out loud and shout that their parents don't love them if they don't want to buy them their product?
World Class Winery - Plant Vineyard above, Store Vintage below
Of all the cool things one can do with a nuclear missile launch site he thinks of making a wine cellar out of it? I can't believe my eyes!
Seriously... I wouldn't want to live there. What about contamination? Radon build-up can always pose a problem in underground places, especially if they were at one time used to store nuclear material.
Later titan missiles also used hypergolic fuel, which means that not so long ago a large quantity of toxic chemicals was stored in that bunker.
A turist attraction perhaps, but certainly not a healthy peaceful retreat...
Chip-generated heat, for example, can cause blade servers in densely packed racks to overheat, and can suck up notebook battery juice by requiring power-hungry coolant systems.
Your average CPU fan will consume approximately 0.5W of power. It is cheap, relatively reliable and it works.
This fan alone would run for about 70 hours on a 3000mAh battery. Compare that to the average battery life time of a modern laptop and you will see that fans are not exactly power-hungry coolant systems.
Why replace something that works well? I believe we need more efficient chips, not better cooling technology.
the bad ones are the ones that have screwed all your backups before you realise.
Please tell which vulnerability would screw all my properly made backups? By properly made backup I mean a backup that is made regulary to an external medium, like a tape or CDR, and is regulary verified to be readable.
Backups that can be destroyed by a software flaw without an intervention of an operator aren't worth much.
Essentially if you want to be certain that a multi-user system has not been hacked, you need to reinstall the operating system from scratch, formatting all the disks...
Each time a new local/remote root vulnerability is found the only way to be certain you haven't been cracked is to reinstall from scratch.
Even if this vulnerability would cause some log messages or other symptoms an attacker with root privileges could easily erase them.
I don't know about dark energy, but there is more direct proof for the existance of dark matter than background radiation and galaxy clusters.
Take a few neighbouring galaxies for example. We can measure the velocity of stars orbiting the center using Doppler effect, which is pretty accurate. The problem is that all stars circle the center in approximately same time while gravitational therory predicts that those stars that are on the rim of the galaxy should take longer to make one orbit. That can only be explained with a large halo of dark matter that sourunds the galaxy and holds more mass than the visible (light-emitting) matter in the galaxy.
Current theory adequately explains why gravity can only be attractive and never repulsive. Unfortunately I can't remember the details (something about the spin?). I was studying this topic three years ago and never understood it completely. Our physics professor did explain it though.
Our monopolistic goverment-owned telecom charges from $34 (1024/256 kbps) to $79 (4096/768 kbps) per month for an ADSL line. One-time connection fee is around $160.
You can also get cable access in some bigger cities for about the same price, but most cable operators set a very low limit on MB/month (as low as 500MB/month in one case in know) and charge insane amounts of money if you download more.
Like some other guys here I find this game a horrible example of bad taste.
I believe our civilization is digging it's grave with stuff like this. With violent video games we are teaching younger generations that killing little figures on the screen is nothing bad.
Some earlier posts said that games are not about reality. I certainly agree with them that most (if not all) people will never think about repeating actions from a game in real life.
But think again how today's wars are being fought. Pilots on a modern bomber are actually playing a very sophisticated video game. They see icons on screens. They push the button and the icon disappears. I doubt they feel sorry for that icon. When they have time to think that that icon represented fifty people it is too late. The same goes from tanks to ICBMs.
The instinct that keeps us from killing each other on the street and that tells us that hurting another one of your species is wrong doesn't work here. And guess what, even infantry is being equiped with HUDs. Soon no soldier will ever see a speck of blood. They will only shoot vectorized figures on the screen. And because they have grown up with killing people on the computer screen they won't find this wrong.
In the past you had to have a very good reason to fight with someone. Now people voluntarily join the army just to play a more sophisticated video game.
Graetz bridge is indeed used in power supplies, but it still draws current only when the absolute value of AC voltage is greater than the voltage on the capacitor. And that happens only on the top and the bottom of the sine wave.
I am not talking about power factor here. Power factor is not such a problem, because it does not affect the losses in the transformers or the power plants. The effect I mentioned can be measured with the klirr factor (RMS value of the higher harmonic currents over RMS value of the entire current).
If a machine has power factor != 1 it only means that the current and voltage are not in phase with each other.
This is not such a big problem because power plants with synchronous generators can compensate for this effect. But there is absolutely nothing you can do against higher harmonic currents on the power plant side.
Almost all power supplies for consumer electronics, together with so-called energy saving light bulbs, LED lights, etc. cause significant losses in the power distribution networks. Why? Because they draw current only on the top of the sine wave.
Think about it. The first stage of most power supplies is a simple rectifier circuit. A capacitor that is charged through a couple of diodes. Diodes are open only when the line voltage is grater than the capacitor voltage. And that happens only on the top of the sine wave.
Why is this a Bad Thing? Because if you make a Fourier analysis of the current you will see that a large part of the current has a higher frequency than the normal 50/60 Hz. This is called higher harmonic current and the transformers in the power distribution networks really suck at transforming it (the losses in the ferromagnetic core of the transformer rise with the square of the frequency!).
Everyone that talks how LED lights and those fluorescent light bulbs will save environment doesn't know what he is talking about. The losses only move from your house to the nearby transformer (But of course, you do not care about that, do you? You only care how much you pay for your electricity bill).
I really hope that this new kind of a power supply doesn't have these drawbacks. It would really make life easier for folks that take care of the distribution network.
I know that DC power transmission went out with Westinghouse's AC transmission, mostly because DC doesn't really work over significant distances.
Actually DC power transmission becomes more efficient than AC at very large distances.
There is a certain threshold distance where capacitive losses in transmission lines become greater than losses in rectifiers and inverters.
For example electricity from the Itaipu power plant in Brazil is transformed to high voltages with regular transformers, then rectified to direct current. On the other side of the long transmission lines is a large inverter that turns DC back to AC that can then be transformed to lower voltages.
Slashdot Mirror
That is 13:30 GMT or 15:30 CEST
That's a taikonaut, not taukonaut.
strap a helium baloon to it!
I imagine you would need quite a large volume of helium to lift something like that.
Did you ever try to hang something to that helium baloon you got for free at the fair? It can lift a piece of paper and not much more.
Check this flying saucer. This big bag of helium can lift only a small battery, receiver and an electric motor. Strap a PDA to it, and you would probably need twice the volume.
I guess you could do better if you used hydrogen, but then I don't think anyone would be confortable with a big bag of explosive gas automaticaly following him.
Be carefull if you are using a reflector-type telescope - one with the mirror (for example Newton reflector). These kind of telescopes should never be pointed towards the sun - whether you are looking through the eyepiece or only projecting a picture of the sun to a screen.
Because the mirror focuses the light, the lenses in the eyepiece can get very hot and can deform or even shatter.
Better stay with binoculars. You can even use two pieces of paper. One black with a tiny hole and another one white to use as a screen.
You don't have to be subjected to 30 second commercials before the previews and the movie.
No... But instead you are subjected to five 30 second FBI warnings in five different languages (and your player won't let you skip them).
I have also seen a number of rented DVDs that include trailers for "comming soon" movies that are played before the movie and you also can't skip through them.
Inertia exerts stresses on different points of the structure than gravity does. Take for example the arm of the space shuttle. It can move huge loads in and out of the shuttle's cargo bay while it is in orbit , but it can't even lift itself when the shuttle is on the ground
I doubt that these android robots can even stand upright on the surface of any planet. If they were designed for operation in zero gravity their framework is probably to weak to support the full weight.
The article does not mention that, but I think these robots will be remotely controlled from the earth. This is the simplest way to do it in earth orbit. Why bother with a complicated computer intelligence, when you can use a human operator? Of course, this wouldn't work for mars because of the time lag.
Also I wonder what kind of a power supply do they use? If they are really the size of a man, they don't have plenty of room for bulky fuel cells, which means that their autonomous time must be pretty short.
This is not working if you have all the latest security fixes installed.
Am I the only one that is disgusted by all these "Need to Convince Mom and Dad?" buttons (see bottom left) that are popping up everywhere?
I mean, how long before companies begin to advise children to cry out loud and shout that their parents don't love them if they don't want to buy them their product?
Yeah, it's a bit offtopic. I know.
Explorer and Internet explorer were still (more or less) separate programs in win95. Browser integration came later (ie4.0 on win95 or win98)
On a fresh install of windows95, an explorer window would include only a menu bar and a tool bar with icons like copy, paste, etc.
And yes, I did find this feature highly unusable. Haven't tried the new Nautilus though.
Google for "nasa advanced propulsion" and "nasa breakthrough propulsion" for some answers.
I'm afraid we won't see anything like the warp drive in our life time though.
World Class Winery - Plant Vineyard above, Store Vintage below
Of all the cool things one can do with a nuclear missile launch site he thinks of making a wine cellar out of it? I can't believe my eyes!
Seriously... I wouldn't want to live there. What about contamination? Radon build-up can always pose a problem in underground places, especially if they were at one time used to store nuclear material.
Later titan missiles also used hypergolic fuel, which means that not so long ago a large quantity of toxic chemicals was stored in that bunker.
A turist attraction perhaps, but certainly not a healthy peaceful retreat...
Chip-generated heat, for example, can cause blade servers in densely packed racks to overheat, and can suck up notebook battery juice by requiring power-hungry coolant systems.
Your average CPU fan will consume approximately 0.5W of power. It is cheap, relatively reliable and it works.
This fan alone would run for about 70 hours on a 3000mAh battery. Compare that to the average battery life time of a modern laptop and you will see that fans are not exactly power-hungry coolant systems.
Why replace something that works well? I believe we need more efficient chips, not better cooling technology.
the bad ones are the ones that have screwed all your backups before you realise.
Please tell which vulnerability would screw all my properly made backups? By properly made backup I mean a backup that is made regulary to an external medium, like a tape or CDR, and is regulary verified to be readable.
Backups that can be destroyed by a software flaw without an intervention of an operator aren't worth much.
Essentially if you want to be certain that a multi-user system has not been hacked, you need to reinstall the operating system from scratch, formatting all the disks...
Each time a new local/remote root vulnerability is found the only way to be certain you haven't been cracked is to reinstall from scratch.
Even if this vulnerability would cause some log messages or other symptoms an attacker with root privileges could easily erase them.
I don't know about dark energy, but there is more direct proof for the existance of dark matter than background radiation and galaxy clusters.
Take a few neighbouring galaxies for example. We can measure the velocity of stars orbiting the center using Doppler effect, which is pretty accurate. The problem is that all stars circle the center in approximately same time while gravitational therory predicts that those stars that are on the rim of the galaxy should take longer to make one orbit. That can only be explained with a large halo of dark matter that sourunds the galaxy and holds more mass than the visible (light-emitting) matter in the galaxy.
Compton scattering can't explain that.
Current theory adequately explains why gravity can only be attractive and never repulsive. Unfortunately I can't remember the details (something about the spin?). I was studying this topic three years ago and never understood it completely. Our physics professor did explain it though.
Our monopolistic goverment-owned telecom charges from $34 (1024/256 kbps) to $79 (4096/768 kbps) per month for an ADSL line. One-time connection fee is around $160.
You can also get cable access in some bigger cities for about the same price, but most cable operators set a very low limit on MB/month (as low as 500MB/month in one case in know) and charge insane amounts of money if you download more.
I only applied the patch-2.4.24 and recompiled the kernel. I didn't enable or disable any features. The configuration files are exactly the same.
If the only changes from 2.4.23 to 2.4.24 were some "minor" bug fixes, why do I see such a big difference in the size of the kernel binary?
-rw-r--r-- 1 root root 667113 Dec 1 22:44 vmlinuz-2.4.23
-rw-r--r-- 1 root root 713946 Jan 5 18:53 vmlinuz-2.4.24
Like some other guys here I find this game a horrible example of bad taste.
I believe our civilization is digging it's grave with stuff like this. With violent video games we are teaching younger generations that killing little figures on the screen is nothing bad.
Some earlier posts said that games are not about reality. I certainly agree with them that most (if not all) people will never think about repeating actions from a game in real life.
But think again how today's wars are being fought. Pilots on a modern bomber are actually playing a very sophisticated video game. They see icons on screens. They push the button and the icon disappears. I doubt they feel sorry for that icon. When they have time to think that that icon represented fifty people it is too late. The same goes from tanks to ICBMs.
The instinct that keeps us from killing each other on the street and that tells us that hurting another one of your species is wrong doesn't work here. And guess what, even infantry is being equiped with HUDs. Soon no soldier will ever see a speck of blood. They will only shoot vectorized figures on the screen. And because they have grown up with killing people on the computer screen they won't find this wrong.
In the past you had to have a very good reason to fight with someone. Now people voluntarily join the army just to play a more sophisticated video game.
Graetz bridge is indeed used in power supplies, but it still draws current only when the absolute value of AC voltage is greater than the voltage on the capacitor. And that happens only on the top and the bottom of the sine wave.
I am not talking about power factor here. Power factor is not such a problem, because it does not affect the losses in the transformers or the power plants. The effect I mentioned can be measured with the klirr factor (RMS value of the higher harmonic currents over RMS value of the entire current).
If a machine has power factor != 1 it only means that the current and voltage are not in phase with each other.
This is not such a big problem because power plants with synchronous generators can compensate for this effect. But there is absolutely nothing you can do against higher harmonic currents on the power plant side.
Almost all power supplies for consumer electronics, together with so-called energy saving light bulbs, LED lights, etc. cause significant losses in the power distribution networks. Why? Because they draw current only on the top of the sine wave.
Think about it. The first stage of most power supplies is a simple rectifier circuit. A capacitor that is charged through a couple of diodes. Diodes are open only when the line voltage is grater than the capacitor voltage. And that happens only on the top of the sine wave.
Why is this a Bad Thing? Because if you make a Fourier analysis of the current you will see that a large part of the current has a higher frequency than the normal 50/60 Hz. This is called higher harmonic current and the transformers in the power distribution networks really suck at transforming it (the losses in the ferromagnetic core of the transformer rise with the square of the frequency!).
Everyone that talks how LED lights and those fluorescent light bulbs will save environment doesn't know what he is talking about. The losses only move from your house to the nearby transformer (But of course, you do not care about that, do you? You only care how much you pay for your electricity bill).
I really hope that this new kind of a power supply doesn't have these drawbacks. It would really make life easier for folks that take care of the distribution network.
I know that DC power transmission went out with Westinghouse's AC transmission, mostly because DC doesn't really work over significant distances.
Actually DC power transmission becomes more efficient than AC at very large distances.
There is a certain threshold distance where capacitive losses in transmission lines become greater than losses in rectifiers and inverters.
For example electricity from the Itaipu power plant in Brazil is transformed to high voltages with regular transformers, then rectified to direct current. On the other side of the long transmission lines is a large inverter that turns DC back to AC that can then be transformed to lower voltages.