Yeah pretty much. The research I did with graphene was on the "micromechanical cleavage" method (no, not small robot boobs). Basically we'd take a flake of graphite maybe 1mm square, then thin it using scotch tape and then press the tape to a silicon wafer. You can then hunt around for graphene flakes if the wafer has an appropriate thickness of oxide grown on it. The graphene flakes you find in this method are generally 10 square microns, but you can get some that are about 60 microns by 40 microns or so on very rare occasions.
It's basically due to the fact you outlined: While the carbon atoms in each sheet are bonded to each other very well, the bonding between sheets is very weak. I suppose you could make "pure" graphite (although pure is not the right word), and have perfect sheets stacked on each other to make a piece of graphite similar to a phonebook, however normal graphite has little flakes of graphene all stuck together somewhat haphazardly.
In terms of thickness, sure it's as you say (roughly), that you can double the strength by doubling the layers but just because something has a good tensile strength doesn't mean it is ideal for armor. I am not an armor expert by any means so I'll not comment further.
Besides, there are cooler things to do with graphene than make armor:)
Well my graphene researching days are over now, but I keep an eye on things due to personal interest.
Sort of. Actually, it's probably more accurate to say that nanotubes are rolled-up graphene. And yes, graphene is extremely strong. I've seen sheets of it cantilevered out over tens of microns. This is roughly equivalent to taking a sheet of normal paper, holding it in your hands, and having it stick out for well over a football field away from you, perfectly rigid.
As strong as it is per unit thickness it is extremely thin (0.34 nm is the number usually quoted), so the total strength isn't useful for armor. After all, graphite is just this stuff layered up millions of times.
The 2D mesh is what makes it stronger than diamond because the sp2 bonds are stronger than the sp3 bonds in diamond are.
This isn't a huge breakthrough. First, their dirac peaks, while graphene-like, look horrible. This means the quality of graphene they are dealing with is very low. In fact, they don't thermally decompose all of the SiC, so they're still not much different than the SiC decomposition method.
Something like this method holds much more promise. CVD growth of graphene on a copper substrate and subsequent rapid etching of the copper yields HUGE 30+" sheets of single to tri-layer graphene films.
Read the links. Fring works over 3G right now.
Also, the skype app might be 3G enabled, just that it's not allowed to be used, similar to the state of the Fring app.
I don't think this had to do with approval. Apparently the Fring client had the feature, but for some reason it didn't work until this morning.
"How do I get this update?
You don’t need to do anything to get this update. Just open fring on your iPhone and you are good to go!
If you still get the message that “voip calls are not allowed” – Just click on “More” –> “Go offline” and open fring again."
I performed very similar research in a lab. The technique used is called a mechanically controllable break junction (MCBJ). Basically you make a very thin gold bridge using fairly standard e-beam nanofabrication procedures on a flexible substrate. You then bend the substrate and can thin the gold bridge down to a single atom in one-atom steps, then to a tunnel gap. You can then put this gap in a liquid (benzene or some other) and trap molecules in it.
I actually did an undergrad thesis on conduction through a single gold atom and yes, while my device was technically 1 atom large, the entire apparatus was fist-sized. The bendy substrate on which everything was fabricated was about 1" by 0.25" in size. All this for a single atom. Now you can be a bit smarter and do it as a large array on a substrate this size, but still, this is about the size these guys are working with too.
The main benefit of this is that they are testing the physics and properties required to make a molecular transistor. Scaling up to producing billions of these in a usable array is a completely separate problem.
Thermoelectric generators are HORRIBLY inefficient. 1-2% is typical, 5-8% for the good ones. You certainly could not power your house with an ounce of plutonium. The voyager probes get ~160W of electricity out of their RTGs, and use 4.5 kg of plutonium.
"The extreme scientists at the Defense Advanced Research Projects Agency today said last month they want to develop a laser system the goes way beyond today's opto-mechanical, acousto-optical or electro-optical systems to establish photonic integrated circuit (PIC) technology that will provide video frame rate beam steering speeds, and emit multiple beams with a total output power of 10 W."
Sweet. What school do I apply to in order to become an EXTREME scientist?
Does this mean when I'm late on a corner in a racing game that turning the controller hard into the turn, shaking it up and down, and leaning my body to the right might actually work?!
I have a pair of Saucony runners I used for treadmill running in the winter. I started running regularly with them in January, and after 3 months and 20 lbs lost, I got stress fractures in my shins.
During the 3 weeks of healing time I read up on running injuries and came across the barefoot running idea. I picked up some VFFs and have been running in them ever since.
My first run on the treadmill with the VFFs was painful. After 2 miles my calves were dead and I had trouble walking for 3 days (START WITH A SHORT RUN PEOPLE!). I managed another 1/2 mile run on the treadmill with them 4 days later.
After that I switched to running outside as the weather got better. Running in the VFFs outside is just, well, fantastic. You really do feel like you're gliding, and you will naturally change your gait in them. I run on sidewalk, road, grass, and trails and haven't been hurt yet.
I also work in nanotechnology doing physics research. PRL definitely is the premier journal for physics research.
Nature is probably the most popular and is where all the big discoveries go, but the articles are watered down to reach the broader audience.
I've also met Wolkow - nice guy:)
Actually, one of the proposed solutions to the velocity anomalies exhibited by the probes is that they may be radiating their generated heat asymmetrically. One type of radiation pressure engine would be to heat a piece of the spacecraft which points "backwards" and surround it in a reflective cone. The heat generated will largely be radiated "backwards" thus pushing the spacecraft "forwards".
I was going to make a ring out of Rhenium. It's rarer than platinum, was the last naturally occurring element to be isolated, and is virtually indestructible. I found enough of it on ebay, and have access to a high-vacuum ebeam system to melt the metal, but couldn't get a nice crucible for it. I was lazy and ended up with a tungsten carbide ring which I love.
About all materials flowing:
I did my undergrad in astrophysics and now work in condensed matter. During my undergrad degree I took some instrumentation classes and apparently the crown glass used to make mirrors in telescopes do in fact "flow" or creep with time as the heavy pieces of glass are tilted for long periods of time. It's nothing you'd be able to see by eye, but even a few hundred nanometers of creep can distort your optical image somewhat and is noticeable. I'm not 100% sure of this, but it seems to be what I remember.
That's not quite right though as in order for LHC to produce a black hole it requires extra dimensions of some small size. The more dimensions and the larger they are, the easier it would be to produce a black hole. You then would have to re-calculate all your forces in this new higher dimensional space.
My reason for believing that there won't be any problems with LHC is because they NEED extra dimensions in order to produce a black hole and I don't think they'll get one because of this.
FYI: To produce a black hole with 3 space + 1 time dimension, LHC would have to operate at 10^19 GeV. It's operating at 10^4 GeV.
Slashdot Mirror
For writing on these sheets with?
Yeah pretty much. The research I did with graphene was on the "micromechanical cleavage" method (no, not small robot boobs). Basically we'd take a flake of graphite maybe 1mm square, then thin it using scotch tape and then press the tape to a silicon wafer. You can then hunt around for graphene flakes if the wafer has an appropriate thickness of oxide grown on it. The graphene flakes you find in this method are generally 10 square microns, but you can get some that are about 60 microns by 40 microns or so on very rare occasions.
It's basically due to the fact you outlined: While the carbon atoms in each sheet are bonded to each other very well, the bonding between sheets is very weak. I suppose you could make "pure" graphite (although pure is not the right word), and have perfect sheets stacked on each other to make a piece of graphite similar to a phonebook, however normal graphite has little flakes of graphene all stuck together somewhat haphazardly. In terms of thickness, sure it's as you say (roughly), that you can double the strength by doubling the layers but just because something has a good tensile strength doesn't mean it is ideal for armor. I am not an armor expert by any means so I'll not comment further. Besides, there are cooler things to do with graphene than make armor :)
Well my graphene researching days are over now, but I keep an eye on things due to personal interest.
Sort of. Actually, it's probably more accurate to say that nanotubes are rolled-up graphene. And yes, graphene is extremely strong. I've seen sheets of it cantilevered out over tens of microns. This is roughly equivalent to taking a sheet of normal paper, holding it in your hands, and having it stick out for well over a football field away from you, perfectly rigid. As strong as it is per unit thickness it is extremely thin (0.34 nm is the number usually quoted), so the total strength isn't useful for armor. After all, graphite is just this stuff layered up millions of times. The 2D mesh is what makes it stronger than diamond because the sp2 bonds are stronger than the sp3 bonds in diamond are.
This isn't a huge breakthrough. First, their dirac peaks, while graphene-like, look horrible. This means the quality of graphene they are dealing with is very low. In fact, they don't thermally decompose all of the SiC, so they're still not much different than the SiC decomposition method. Something like this method holds much more promise. CVD growth of graphene on a copper substrate and subsequent rapid etching of the copper yields HUGE 30+" sheets of single to tri-layer graphene films.
So I guess if you ban cell phones and texting, they'll just pick up iPods or a BigMac and crash while chowing down.
Read the links. Fring works over 3G right now. Also, the skype app might be 3G enabled, just that it's not allowed to be used, similar to the state of the Fring app.
I don't think this had to do with approval. Apparently the Fring client had the feature, but for some reason it didn't work until this morning. "How do I get this update? You don’t need to do anything to get this update. Just open fring on your iPhone and you are good to go! If you still get the message that “voip calls are not allowed” – Just click on “More” –> “Go offline” and open fring again."
Yep, but the iPhone didn't allow it. Now you have both the provider and the platform allowing it.
The Fring blog says you may have to log out of fring, shut down the app and restart.
I performed very similar research in a lab. The technique used is called a mechanically controllable break junction (MCBJ). Basically you make a very thin gold bridge using fairly standard e-beam nanofabrication procedures on a flexible substrate. You then bend the substrate and can thin the gold bridge down to a single atom in one-atom steps, then to a tunnel gap. You can then put this gap in a liquid (benzene or some other) and trap molecules in it. I actually did an undergrad thesis on conduction through a single gold atom and yes, while my device was technically 1 atom large, the entire apparatus was fist-sized. The bendy substrate on which everything was fabricated was about 1" by 0.25" in size. All this for a single atom. Now you can be a bit smarter and do it as a large array on a substrate this size, but still, this is about the size these guys are working with too. The main benefit of this is that they are testing the physics and properties required to make a molecular transistor. Scaling up to producing billions of these in a usable array is a completely separate problem.
Thermoelectric generators are HORRIBLY inefficient. 1-2% is typical, 5-8% for the good ones. You certainly could not power your house with an ounce of plutonium. The voyager probes get ~160W of electricity out of their RTGs, and use 4.5 kg of plutonium.
"The extreme scientists at the Defense Advanced Research Projects Agency today said last month they want to develop a laser system the goes way beyond today's opto-mechanical, acousto-optical or electro-optical systems to establish photonic integrated circuit (PIC) technology that will provide video frame rate beam steering speeds, and emit multiple beams with a total output power of 10 W." Sweet. What school do I apply to in order to become an EXTREME scientist?
Nope it won't disappear. I've still got GV Mobile on my touch.
Does this mean when I'm late on a corner in a racing game that turning the controller hard into the turn, shaking it up and down, and leaning my body to the right might actually work?!
I have a pair of Saucony runners I used for treadmill running in the winter. I started running regularly with them in January, and after 3 months and 20 lbs lost, I got stress fractures in my shins. During the 3 weeks of healing time I read up on running injuries and came across the barefoot running idea. I picked up some VFFs and have been running in them ever since. My first run on the treadmill with the VFFs was painful. After 2 miles my calves were dead and I had trouble walking for 3 days (START WITH A SHORT RUN PEOPLE!). I managed another 1/2 mile run on the treadmill with them 4 days later. After that I switched to running outside as the weather got better. Running in the VFFs outside is just, well, fantastic. You really do feel like you're gliding, and you will naturally change your gait in them. I run on sidewalk, road, grass, and trails and haven't been hurt yet.
I also work in nanotechnology doing physics research. PRL definitely is the premier journal for physics research. Nature is probably the most popular and is where all the big discoveries go, but the articles are watered down to reach the broader audience. I've also met Wolkow - nice guy :)
[neo]whoa[/neo] It could therefore be a relativistic effect?
Actually, one of the proposed solutions to the velocity anomalies exhibited by the probes is that they may be radiating their generated heat asymmetrically. One type of radiation pressure engine would be to heat a piece of the spacecraft which points "backwards" and surround it in a reflective cone. The heat generated will largely be radiated "backwards" thus pushing the spacecraft "forwards".
Oh, and I was going to have a custom engagement ring made too using a CVD grown boron-doped diamond so it had a blue tinge to it.
I was going to make a ring out of Rhenium. It's rarer than platinum, was the last naturally occurring element to be isolated, and is virtually indestructible. I found enough of it on ebay, and have access to a high-vacuum ebeam system to melt the metal, but couldn't get a nice crucible for it. I was lazy and ended up with a tungsten carbide ring which I love.
Isn't it what they program rotary phones with?
But but... it's raining freaking gasoline there!!! I guess the real industry on titan would be oxygen mining. Seems the grass is always greener...
About all materials flowing: I did my undergrad in astrophysics and now work in condensed matter. During my undergrad degree I took some instrumentation classes and apparently the crown glass used to make mirrors in telescopes do in fact "flow" or creep with time as the heavy pieces of glass are tilted for long periods of time. It's nothing you'd be able to see by eye, but even a few hundred nanometers of creep can distort your optical image somewhat and is noticeable. I'm not 100% sure of this, but it seems to be what I remember.
That's not quite right though as in order for LHC to produce a black hole it requires extra dimensions of some small size. The more dimensions and the larger they are, the easier it would be to produce a black hole. You then would have to re-calculate all your forces in this new higher dimensional space. My reason for believing that there won't be any problems with LHC is because they NEED extra dimensions in order to produce a black hole and I don't think they'll get one because of this. FYI: To produce a black hole with 3 space + 1 time dimension, LHC would have to operate at 10^19 GeV. It's operating at 10^4 GeV.