Home | Join! | Help | Browse | Forums | NuWorld | NWF | PoPo   

So we fix our eyes not on what is seen, but on what is unseen, since what is seen is temporary, but what is unseen is eternal.


The Profile


Zanzibar
Age. 39
Gender. Female
Ethnicity. that of my father and his father before him
Location Altadena, CA
School. Other
» More info.
The World









The Link To Zanzibar's Past
This is my page in the beloved art community that my sister got me into:

Samarinda

Extra points for people who know what Samarinda is.
The Phases of the Moon Module
CURRENT MOON
Croc Hunter/Combat Wombat
My hero(s)
Only My Favorite Baseball Player EVER


Aw, Larry Walker, how I loved thee.
The Schedule
M: Science and Exploration
T: Cook a nice dinner
W: PARKOUR!
Th: Parties, movies, dinners
F: Picnics, the Louvre
S: Read books, go for walks, PARKOUR
Su: Philosophy, Religion
The Reading List
This list starts Summer 2006
A Crocodile on the Sandbank
Looking Backwards
Wild Swans
Exodus
1984
Tales of the Alhambra (in progress)
Dark Lord of Derkholm
Do Androids Dream of Electric Sheep?
The Lost Years of Merlin
Harry Potter a l'ecole des sorciers (in progress)
Atlas Shrugged (in progress)
Uglies
Pretties
Specials
A Long Way Gone (story of a boy soldier in Sierra Leone- met the author! w00t!)
The Eye of the World: Book One of the Wheel of Time
From Magma to Tephra (in progress)
Lady Chatterley's Lover
Harry Potter 7
The No. 1 Lady's Detective Agency
Introduction to Planetary Volcanism
A Child Called "It"
Pompeii
Is Multi-Culturalism Bad for Women?
Americans in Southeast Asia: Roots of Commitment (in progress)
What's So Great About Christianity?
Aeolian Geomorphology
Aeolian Dust and Dust Deposits
The City of Ember
The People of Sparks
Cube Route
When I was in Cuba, I was a German Shepard
Bound
The Golden Compass
Clan of the Cave Bear
The 9/11 Commission Report (2nd time through, graphic novel format this time, ip)
The Incredible Shrinking Man
Twilight
Eclipse
New Moon
Breaking Dawn
Armageddon's Children
The Elves of Cintra
The Gypsy Morph
Animorphs #23: The Pretender
Animorphs #25: The Extreme
Animorphs #26: The Attack
Crucial Conversations
A Journey to the Center of the Earth
A Great and Terrible Beauty
The Absolutely True Diary of a Part-Time Indian
Dandelion Wine
To Sir, With Love
London Calling
Watership Down
The Invisible
Alice in Wonderland
Through the Looking Glass
20,000 Leagues Under the Sea
The Host
The Hunger Games
Catching Fire
Shadows and Strongholds
The Jungle Book
Beatrice and Virgil
Infidel
Neuromancer
The Help
Flip
Zion Andrews
The Unit
Princess
Quantum Brain
The Immortal Life of Henrietta Lacks
No One Ever Told Us We Were Defeated
Delirium
Memento Nora
Robopocalypse
The Name of the Wind
The Terror
Sister
Tao Te Ching
What Paul Meant
Lao Tzu and Taoism
Libyan Sands
Sand and Sandstones
Lost Christianites: The Battles for Scripture and the Faiths We Never Knew
The Science of God
Calculating God
Great Contemporaries, by Winston Churchill
City of Bones
Around the World in 80 Days, by Jules Verne
Divergent
Stranger in a Strange Land
The Old Man and the Sea
Flowers for Algernon
Au Bonheur des Ogres
The Martian
The Road to Serfdom
De La Terre � la Lune (ip)
In the Light of What We Know
Devil in the White City
2312
The First Fifteen Lives of Harry August
Red Mars
How to Be a Good Wife
A Mote in God's Eye
A Gentleman in Russia
The Fatal Conceit: The Errors of Socialism
Seneca: Letters from a Stoic
The Juanes Module


Juanes just needed his own mod. Who can disagree.
How to Cut Diamonds with Scissors Made of Water
Saturday. 2.16.08 12:49 pm
So in fluid mechanics we were learning about carbon nanotubes. These tiny cylinders (about 10E-09 m in diameter, hence the name) are likely to revolutionize many sectors of industry. They are made out of carbon, with a unique chemical structure making them extremely strong. Like diamonds, they are made of carbon, and their bond structure makes them even stronger than diamonds, depending on which way you try and break them. They tend to aggregate into ropes, and you can fuse them together, creating the possibility of making them into extremely strong wires. They are also good at conducting heat.

So. How does this have to do with a pair of water scissors?

Well, given that carbon nanotubes are so strong, they are exceedly difficult to cut. Engineers would like to cut them to whatever length they desire for their projects, but now they have to deal with the fact that they're going to be whatever length they grow to be (perhaps a couple microns). Thus the problem was put to researchers: How can we cut a micron-scale nanotube accurately when its bonds are stronger than a diamond's? We must make a pair of nanoscissors!

One group tried to do it chemically, sort of how some people cut DNA. But they had to use extremely strong chemicals, and they always ended up destroying the carbon nanotubes instead of cutting them.

Another laboratory decided to cut them physically by mixing them with extremely tiny bits of zircon (a very hard and resilient mineral), and then shaking the container. Unfortunately, this method also usually reduced the carbon nanotubes to bits or damaging them instead of cutting them.

Enter the group at Brown. Fluid mechanicians, they decide to cut the carbon nanotubes using water. How? Cavitation, of course!

Cavitation is a process by which turbulence or disturbences (pressure waves, what have you) in a liquid cause tiny areas where the pressure is low enough for the liquid to turn into a gas. This is kind like boiling, except boiling is usually accompanied by temperature rising enough to turn the liquid to a gas, because the state of a material is dependent on both temperature and pressure. But even when boiling, the first bubbles usually nucleate on contaminating particles or along the wall of the container, where local pressure is slightly lower.
After these bubbles form, they almost immediately collapse after the pressure goes back to normal. They collapse at super-sonic speed, and because the process is adiabatic, as the volume shrinks, the temperature goes way up-- to the tune of some 5000 degrees C. The energy produced very locally by this process is so high that the popping bubbles often give off sparks as they collapse, as well as pressure waves that can be heard as very loud sounds.

This aspect of cavitation makes it a huge engineering concern, and a big concern for secret spy nuclear submarines (see: Hunt for the Red October, "We're cavitating!!!") Cavitating makes a huge number of extremely loud pops, which can be easily picked up by the sonar on other vessels (i.e., Commies!!). The skins of submarines are optimized to reduce cavitation as much as possible, but it depends on what maneuvers you are doing. Cavitation can also happen in pistons and pipes and near the propellors of ships. The energy from the popping bubbles wears huge pits into the metal in these systems, incurring a large cost and necessitating the replacement of parts well before they should be worn out.

Cavitation is also a concern when using ultrasound on the body, because pressure waves like those used in ultrasound, if it's turned up too high, can induce cavitation in your blood, wreaking havoc on the nanostructures in your vessels. (Don't worry, they never turn it up that high!)

Cognizant of the effect of cavitation on nanostructures, the people at Brown decided to see how carbon nanotubes reacted to cavitation. As it turns out, if you put a lot of carbon nanotubes into water, when the bubbles form, the nanotubes are attracted to the low pressure region and in a sense adhere to the surface of the bubble. When it collapses, the surface area over which the nanotubes are spread decreases drastically, and the nanotubes buckle... along eigenmodes!

If you imagine pushing a rug from either side, the rug will buckle in a series of folds that are usually evenly spaced. These are the eigenmodes of the rugs, and the spacing between them would be the eigenspacing, as eigen just means "characteristic" in german. But you can change the eigenspacing of your rug by pushing it together with different energies. (It will also have different eigenspacing depending on how stiff a rug it is. You can imagine that a doormat might have only one eigenmode, while a blanket would have a lot.)

So, by controlling the size of the bubbles that form (by controlling the kind of sonic waves that initiate the cavitation), you can cut the carbon nanotubes to pretty much any length you want!

Using scissors.... MADE OF WATER!!!

Anyway, that was a really cool class.
5 Comments.


Speaking of diamonds,
have you seen... Diamonds in the microwave?
» ikimashokie on 2008-02-16 01:52:40

Add that to random's list of ways to die.
Death by cativation of the blood. Ew. Did you know that the pistol shrimp uses the same phenomenon to stun or kill prey?

Of course you did.
» middaymoon on 2008-02-16 02:25:27

The chemical properties of carbon nanotubes (and other carbon nanostructures like fullerenes) are interesting as well. While carbon is normally thought to act more like an insulator than a conductor, carbon nanotubes have pi bond delocalization along their surfaces, making them great conductors. Altering the arrangement of pi bonds over the surface through chemical means can also transform carbon nanotubes into semiconductors. There's a lot of research going into using carbon nanotubes in circuits and other electrical applications.

Carbon chemistry is so awesome. All hail the tetravalent element--the basis of all life as we know it (or rather, as we have confirmed exists)!
» ranor on 2008-02-16 02:55:29

Oh, and by the way.
I've read that microtubials in brain cells give our brains their ability to tap into quantum fluctuations that are too small to normally make any chemical differences. How neat is that?
» middaymoon on 2008-02-16 05:59:53

Re:middaymoon
That's hotly debated. The idea of quantum consciousness/quantum mind is a fringe theory in modern neuroscience and physics. I think the idea itself is very cool, but we are a LONG way away from a paradigm shift in the direction of quantum consciousness.
» ranor on 2008-02-16 10:19:05

Name.

URL.

[to enter your email, use "mailto:youremail@domain.com"]
Subject.

Comment.

Word verification.

Copy the first 4 characters only.

If you are a member, try logging in again or accessing this page here.

Zanzibar's Weblog Site • NuTang.com

NuTang is the first web site to implement PPGY Technology. This page was generated in 0.628seconds.

  Send to a friend on AIM | Set as Homepage | Bookmark Home | NuTang Collage | Terms of Service & Privacy Policy | Link to Us | Monthly Top 10s
All content © Copyright 2003-2047 NuTang.com and respective members. Contact us at NuTang[AT]gmail.com.