BF2S Forums D&ST - Science

JohnG@lt wrote:

Trotskygrad wrote:

seems like there's 2 types of transparent aluminum...

Actual Transparent Aluminum

http://en.wikipedia.org/wiki/Transparent_aluminium

and Aluminum Oxynitride

http://en.wikipedia.org/wiki/Aluminium_oxynitride

looks like you're talking about ALON

Transparent aluminium is a state of aluminium achieved by bombarding a thin (50 nm) Al foil with soft X-ray laser radiation (wavelength 13.5 nm). The short laser pulse knocks out a core L-shell electron from every aluminium atom without breaking the crystalline structure of the metal making it transparent to soft X-rays of the same wavelength.[1] This phenomenon is called saturable absorption. The thus produced transient state of aluminium is as dense as ordinary matter but can only exist for an extremely short period of time, as the energy required to maintain the high temperature which would be necessary to hold it in this state would be enormous. To create transparent aluminium, more power than is used by an entire city had to be focused into a dot with a diameter of less than one-twentieth the thickness of a human hair, and then could only maintain the transparent state for 40 femtoseconds.

LOL.

SenorToenails wrote:

JohnG@lt wrote:

Trotskygrad wrote:

seems like there's 2 types of transparent aluminum...

Actual Transparent Aluminum

http://en.wikipedia.org/wiki/Transparent_aluminium

and Aluminum Oxynitride

http://en.wikipedia.org/wiki/Aluminium_oxynitride

looks like you're talking about ALON

Transparent aluminium is a state of aluminium achieved by bombarding a thin (50 nm) Al foil with soft X-ray laser radiation (wavelength 13.5 nm). The short laser pulse knocks out a core L-shell electron from every aluminium atom without breaking the crystalline structure of the metal making it transparent to soft X-rays of the same wavelength.[1] This phenomenon is called saturable absorption. The thus produced transient state of aluminium is as dense as ordinary matter but can only exist for an extremely short period of time, as the energy required to maintain the high temperature which would be necessary to hold it in this state would be enormous. To create transparent aluminium, more power than is used by an entire city had to be focused into a dot with a diameter of less than one-twentieth the thickness of a human hair, and then could only maintain the transparent state for 40 femtoseconds.

LOL.

Gotta love that...'More power than used by an entire city' makes it sounds like a crapload of energy, when in reality the energy was only used at that rate for probably not much longer than that 40 femtoseconds...40x10^-15 seconds.  I wonder how many joules that actually was, lol.

SenorToenails wrote:

JohnG@lt wrote:

SenorToenails wrote:

Gotta love that...'More power than used by an entire city' makes it sounds like a crapload of energy, when in reality the energy was only used at that rate for probably not much longer than that 40 femtoseconds...40x10^-15 seconds.  I wonder how many joules that actually was, lol.

I'm surprised the green police didn't cry.

Eh, more 'power' is used than that on a fairly regular basis in high energy physics.  Since power is just the energy used per unit time, if the energy is used over an insanely short period of time, then the power is going to be huge...but it's not sustained usage.

Take, for example, the Omega Laser at University of Rochester's LLE, which can use 40,000 joules in 1x10^-9 seconds...which leads to a 40 petawatt laser.  zomg!  That's 8000 times the power usage of NYC in 2001!  And yet, the actual energy used was only 40000 J. 

SenorToenails wrote:

JohnG@lt wrote:

SenorToenails wrote:

Eh, more 'power' is used than that on a fairly regular basis in high energy physics.  Since power is just the energy used per unit time, if the energy is used over an insanely short period of time, then the power is going to be huge...but it's not sustained usage.

Take, for example, the Omega Laser at University of Rochester's LLE, which can use 40,000 joules in 1x10^-9 seconds...which leads to a 40 petawatt laser.  zomg!  That's 8000 times the power usage of NYC in 2001!  And yet, the actual energy used was only 40000 J. 

<-- EE major

I know you know, but that was to benefit the rest of the class! 

SenorToenails wrote:

JohnG@lt wrote:

I'm just trying to wrap my head around how large the capacitors would have to be.

Unfortunately, I never got to take the tour that the LLE had when I was an undergrad there...but they do have a huge bank of them.  Check it out!

Mekstizzle wrote:

What is 40,000 Joules anyway. Give us some comparisons. Oh wait, I found one from wiki

3.8×10^4 J ...the energy released by the metabolism of one gram of fat - It's about the same as the KE of twelve 7.62 NATO rounds at muzzle velocity. Didn't realise fat was so ......what's the word, energy good......storage.......battery, thing. Dense?

http://en.wikipedia.org/wiki/Orders_of_magnitude_(energy)

Except it was all in some ridiculously small time, I think that's impressive on its own. That they can do anything for such a short amount of time

Harmor wrote:

Transparent Aluminum (been around for a while but this is the first I've seen of it):

http://img339.imageshack.us/img339/1756 … uminum.jpg

Harmor wrote:

Interesting how this company allows you to take a photo with your phone of someone's driver license and then text the driver of that car:

Scan Someone's License Plate and Message Them Instantly with New Bump App

Is this an example of too much technology?

11 Bravo wrote:

Harmor wrote:

Interesting how this company allows you to take a photo with your phone of someone's driver license and then text the driver of that car:

Scan Someone's License Plate and Message Them Instantly with New Bump App

Is this an example of too much technology?

this is not science this is just plain stupid and dangerous and should not be allowed.

Harmor wrote:

What is pulling on Pioneer 10? 

A Mysterious Force Is Pulling Pioneer 10 Back Toward the Sun.

Looks like the space craft is slowing down by 6mph every century and scientists don't know why.