1. The 11 Times Trick
We all know the trick when multiplying by ten – add 0 to the end of
the number, but did you know there is an equally easy trick for
multiplying a two digit number by 11? This is it:
Take the original number and imagine a space between the two digits (in this example we will use 52:
5_2
Now add the two numbers together and put them in the middle:
5_(5+2)_2
That is it – you have the answer: 572.
If the numbers in the middle add up to a 2 digit number, just insert the second number and add 1 to the first:
9_(9+9)_9
(9+1)_8_9
10_8_9
1089 – It works every time.
2. Quick Square
If you need to square a 2 digit number ending in 5, you can do so
very easily with this trick. Mulitply the first digit by itself + 1,
and put 25 on the end. That is all!
252 = (2x(2+1)) & 25
2 x 3 = 6
625
3. Multiply by 5
Most people memorize the 5 times tables very easily, but when you get
in to larger numbers it gets more complex – or does it? This trick is
super easy.
Take any number, then divide it by 2 (in other words, halve the
number). If the result is whole, add a 0 at the end. If it is not,
ignore the remainder and add a 5 at the end. It works everytime:
2682 x 5 = (2682 / 2) & 5 or 0
2682 / 2 = 1341 (whole number so add 0)
13410
Let’s try another:
5887 x 5
2943.5 (fractional number (ignore remainder, add 5)
29435
4. Multiply by 9
This one is simple – to multiple any number between 1 and 9 by 9 hold
both hands in front of your face – drop the finger that corresponds to
the number you are multiplying (for example 9×3 – drop your third
finger) – count the fingers before the dropped finger (in the case of
9×3 it is 2) then count the numbers after (in this case 7) – the answer
is 27.
5. Multiply by 4
This is a very simple trick which may appear obvious to some, but to
others it is not. The trick is to simply multiply by two, then multiply
by two again:
58 x 4 = (58 x 2) + (58 x 2) = (116) + (116) = 232
6. Calculate a Tip
If you need to leave a 15% tip, here is the easy way to do it. Work
out 10% (divide the number by 10) – then add that number to half its
value and you have your answer:
15% of $25 = (10% of 25) + ((10% of 25) / 2)
$2.50 + $1.25 = $3.75
7. Tough Multiplication
If you have a large number to multiply and one of the numbers is even, you can easily subdivide to get to the answer:
32 x 125, is the same as:
16 x 250 is the same as:
8 x 500 is the same as:
4 x 1000 = 4,000
8. Dividing by 5
Dividing a large number by five is actually very simple. All you do is multiply by 2 and move the decimal point:
195 / 5
Step1: 195 * 2 = 390
Step2: Move the decimal: 39.0 or just 39
2978 / 5
step 1: 2978 * 2 = 5956
Step2: 595.6
9. Subtracting from 1,000
To subtract a large number from 1,000 you can use this basic rule:
subtract all but the last number from 9, then subtract the last number
from 10:
1000
-648
step1: subtract 6 from 9 = 3
step2: subtract 4 from 9 = 5
step3: subtract 8 from 10 = 2
answer: 352
10. Assorted Multiplication Rules
Multiply by 5: Multiply by 10 and divide by 2.
Multiply by 6: Sometimes multiplying by 3 and then 2 is easy.
Multiply by 9: Multiply by 10 and subtract the original number.
Multiply by 12: Multiply by 10 and add twice the original number.
Multiply by 13: Multiply by 3 and add 10 times original number.
Multiply by 14: Multiply by 7 and then multiply by 2
Multiply by 15: Multiply by 10 and add 5 times the original number, as above.
Multiply by 16: You can double four times, if you want to. Or you can multiply by 8 and then by 2.
Multiply by 17: Multiply by 7 and add 10 times original number.
Multiply by 18: Multiply by 20 and subtract twice the original number (which is obvious from the first step).
Multiply by 19: Multiply by 20 and subtract the original number.
Multiply by 24: Multiply by 8 and then multiply by 3.
Multiply by 27: Multiply by 30 and subtract 3 times the original number (which is obvious from the first step).
Multiply by 45: Multiply by 50 and subtract 5 times the original number (which is obvious from the first step).
Multiply by 90: Multiply by 9 (as above) and put a zero on the right.
Multiply by 98: Multiply by 100 and subtract twice the original number.
Multiply by 99: Multiply by 100 and subtract the original number.
Bonus: Percentages
Find 7 % of 300. Sound Difficult?
Percents: First of all you need to understand the word “Percent.” The
first part is PER , as in 10 tricks per listverse page. PER = FOR EACH.
The second part of the word is CENT, as in 100. Like Century = 100
years. 100 CENTS in 1 dollar… etc. Ok… so PERCENT = For Each 100.
So, it follows that 7 PERCENT of 100, is 7. (7 for each hundred, of only 1 hundred).
8 % of 100 = 8. 35.73% of 100 = 35.73
But how is that useful??
Back to the 7% of 300 question. 7% of the first hundred is 7. 7% of
2nd hundred is also 7, and yep, 7% of the 3rd hundred is also 7. So
7+7+7 = 21.
If 8 % of 100 is 8, it follows that 8% of 50 is half of 8 , or 4.
Break down every number that’s asked into questions of 100, if the
number is less then 100, then move the decimal point accordingly.
EXAMPLES:
8%200 = ? 8 + 8 = 16.
8%250 = ? 8 + 8 + 4 = 20.
8%25 = 2.0 (Moving the decimal back).
15%300 = 15+15+15 =45.
15%350 = 15+15+15+7.5 = 52.5
Also it’s usefull to know that you can always flip percents, like 3% of 100 is the same as 100% of 3.
35% of 8 is the same as 8% of 35.
10 Alternative power sources that will blow your mind
Charging Your Phone With Lightning
One of the worst things about having modern smartphones is that upon dying, they take ages to charge. Don’t worry: Mobile phone company Nokia (Microsoft) is on the case. In one of the videos on their blog, the company successfully charged their flagship Lumia 925 to full power in under a minute. How? By collaborating with scientists at the university of Southampton, they were able to safely (and we use that word loosely) create controlled bolts of artificial lightning and directly channel that into the battery. Unfortunately, such technology isn’t available to the general public yet.
9 Flashlight Powered By Body Heat
Flashlights are the most annoying things, always charged up when you don’t need them and instantly dying when you do. To fix that problem, Ann Makosiniki has come up with a creative solution. Utilizing devices known as Peltier tiles, she used the inherent thermal energy present in the hand of a human being to power her led light and discovered that it would be more than enough to power a flashlight. She showcased her gadget at the Google Science Fair—and won in her category.
8 Body Temperature Textile Charges Phone
Ever thought of using the spare heat energy in your pockets for something useful? There’s wasted energy all around us. A team at Southampton’s Electronic and Computer Science Department developed a material that takes advantage of the heat in your pants and converts it to electricity. It doesn’t have to be pant either. It can even be incorporated into sleeping bags. All that’s needed to charge your cell is a plug and you’re golden. Though it can certainly take a while to get a full charge.
7 Urine-Powered Mobile Phones
After research on the effects of bacteria on urine, researchers from the University of Bristol created a fuel cell that uses bacteria to help break down chemicals in urine. The process builds up electric charge, which is then stored in a capacitor. However, before you reach for your wallet and determine which of your kidneys you don’t really need, we would stop and point out that the battery cell is currently the size of a car battery and so useless for anything but a tech-style pissing contest. So far, the power generated has been used to power up a mobile phone and enable internet browsing and SMS. The researchers are working on making it a bit more compact to make it much more usable outside the laboratory.
6 Bacteria-Powered Lightbulb
Slavery and Eugenics are generally bad things for humans. But Bacteria tend not to have many protests against being used as projects. Undergraduates at the University of Wisconsin are developing a device known as a Biobulb , which generates light purely from the power of bacterium. The bacteria involved are E.coli bacteria, which have been reengineered with the gene for bioluminescence. Once this has been done, the bacteria contained inside will glow like jellyfish and fireflies. They would be recharged by ambient light, and should they be successful, we can look forward to lightbulbs that won’t give us mercury poisoning.
5 Shape-Shifting Plastic Powers Motors
A new material has been created that has the ability to change shape and return to its previous form. It contracts when exposed to ultraviolet light and expands back to its original size when exposed to visible light. After continuous expansion and contraction, the material showed no loss in strength over 30 hours, which is unheard of. Its value as a power source lies in the fact that it can be used to create window blinds which open and close according to temperature as well as power motors.
4 Wireless Device That Charges From Signal
One major problem with modern devices is that they require a lot of signal. WiFi, 4G, Bluetooth, and NFC all active at once can drain your battery and leave you with a beautiful glass brick in minutes. University of Washington researchers have developed a technology known as “ambient backscatter” which should change this soon. The device is able to repurpose wireless signals into battery charge. In other words, it can passively charge off of an ambient wireless signal.
3 Wine-Powered Microprocessor
Everyone loves Intel. They make all the stuff that powers your computer and enables you to use this awesome site. You know what people love more than Intel? Red wine. The people at Intel have picked up on this and have decided to produce something that is the best of both worlds. An Intel chip powered purely by energy derived from red wine. We don’t know how it works exactly, but it does. At a conference, an engineer demonstrated this new technology by pouring the liquid on a circuit board in a wine glass. The microprocessor in the board powered up immediately and was able to run a graphics program on a computer. Disregarding sorcery as a possible explanation, we can only conclude that computers powered by this chip will have an 21 and over rating and will be banned in the Middle East.
2 Rubbing Paper Generator
Disney has researched and discovered a new method for generating power through the use of our very own hands and a piece of paper. All that is necessary is for us to stroke the paper for it to generate a current. Using everyday materials like Teflon, Disney research Pittsburg was able to discover a way to generate usable current. When the Teflon is rubbed or tapped with paper, a charge accumulates across the sheet. This current can be used to power sounds, LED lights, and e-ink displays among other devices. Disney claims this can be used to add more interactive features to books inexpensively.
1 Justin Bieber And Linkin’ Park Improve Solar Cell Efficiency
Scientists from the Queen Mary University in London have discovered that playing pop and rock tunes increases the performance of solar cells, which cover the surface of solar panels. They discovered that the vibrations caused by various genres of music increased energy generation in these solar cells. In particular, rock music and pop music led to as much as a 40 percent increase in solar cell efficiency.
Why? Solar cells contain zinc oxide, a material which can generate electricity when bent. As we all know, sounds are vibrations, which slightly bend the zinc, and the higher frequency the sounds, the more electricity is generated.
10 Mind-blowing uses of Urine in modern technology
10 Robot Blood
Who knew our future overlords will be powered by our very own bladders? The guys at the Bristol Robotics Laboratory have created an artificial heart that can power the robots of the future.
As of 2010, there are an estimated 8.6 million robots in the world, employed in different industries and serving different functions. Depending on their purpose, robots are traditionally charged with solar energy, battery power, or electricity. Peter Walters and his colleagues from the University of Bristol have taken a slightly more unconventional route, creating a robot that can charge itself with a urinal.
The scientists built an artificial heart that pumps a regulated supply of human urine into microbial power stations, which then break down urine and convert it into electricity. This artificial heart was able to run a robot called “EcoBot” using nothing but human urine. These robots have been able to function before on other biodegradable materials, but this is the first time that an EcoBot was sustained with power using an artificial heart that pumps urine. The researchers are inspired to make improvements on this pee-pumping heart and hope to see these urine-powered EcoBots being used in the future, especially in green projects such as monitoring pollution.
9 Tracking Climate Change
The rock hyrax, locally known in Africa as pelele, is a mammal of the Hyracoidea order. Small and furry with a close resemblance to a guinea pig, the rock hyrax spends most of its time bathing under the sun or eating grass and leaves. At first glance, the rock hyrax doesn’t seem to be a very special animal – except that its urine will be proven an essential tool for studying climate change.
Whole families of rock hyraxes tend to pick a favorite spot to pee and their quick-drying discharge often capture artifacts of a particular time period—such as pollens, dried leaves, and air bubbles—that provide clues as to how the climate changed during that time. Researchers from France’s Montpelier University studied these dried urine layers and compared them with existing theories about changes in our climate past. They concluded that the urine was consistent in accurately telling the story of how our climate really changed over the years, like how ice glaciers retreated in Europe during the end of the last ice age and how lakes of melted water formed after the planet has warmed. Because of its precision in detailing our climate past, the researchers are hoping that the rock hyrax urine will be a useful tool in making better predictions of future deviations in the climate.
8 A Solution To The Water Crisis
As disgusting as it is, we’ve become inured to images of drinking urine. Aside from it being Bear Grylls’s claim to Internet fame, astronauts regularly recycle urine to quench themselves during manned missions to space. However, scientists warn that drinking urine may no longer be the exclusive territory of TV shows or space shuttles. As our freshwater supply runs dry at an alarming pace, scientists advise that we should also begin treating and drinking our own urine as soon as possible.
With new technology that can treat urine less expensively and more efficiently, the US National Research Council says that reclaiming it for reuse may potentially be a long-term solution to the water crisis. While urine naturally ends back into our water reservoirs, it takes a very long time for it to get back into our natural water system. Directly treating urine from our sewage systems would be much speedier than waiting for it to go back to our waters. The council even suggests advantages of processing urine over freshwater—the health risks of recycling urine may be significantly lower than extracting water from our present sources. We may even be able to recover phosphorus from our urine, which is also currently a dwindling resource.
We are already starting to see a future of reprocessed pee unfold. Because of the harsh drought that has affected many towns in the state, the Texan town of Big Spring has already resorted to reprocessed urine to supply its 27,000 residents with potable water.
7 Fighting Pollution
According to the UN Weather Agency, our levels of CO2 are at an all-time high. The amount of CO2 in the atmosphere in 2012 was at 393.1 parts per million (ppm), 2.2 ppm higher than in 2011. It is predicted that in 2016, the number will reach a staggering 400 ppm, far beyond the 350 ppm that scientists say is the ceiling for a safe level of CO2.
CO2, the main agent of global warming, occurs naturally in the planet. However, human activities like factory work and car emissions multiply our CO2 emissions at a rate that is more than what Mother Earth can take. This makes our planet warmer at a pace we can barely follow, melting our glaciers and drying our lakes before our very eyes. Thankfully, scientists from Andalusia discovered that global warming can be staved off by a bizarre brew of urine and olive waste water. They have found out that this curious cocktail can absorb CO2 when exposed to the air.
The researchers explain that each molecule of urea in urine produces one mole of ammonium bicarbonate and one mole of ammonia, which then absorbs one mole of CO2 from the air, lessening our excessive output of the greenhouse gas. When the CO2 is absorbed, urine produces another mole of ammonium bicarbonate, which can then be used to fertilize our farms. The olive waste water’s role is to prevent the urine from going stale, maximizing the urine’s use until it is saturated with gas. This unique concoction can be strategically installed in chimneys where CO2 emissions usually pass through. A special filling and emptying mechanism can also be added to make replacement of this fluid more convenient.
6 Pee-Powered Smartphones
About half of Americans now use smartphones. These high-end cell phones that can do almost anything won’t be going away soon and it’s only a matter of time before we have to address the issue of their energy consumption.
Thankfully, Dr. Ioannis Ieropoulos of the Bristol Robotics Laboratory is on the job. Earlier this year, he and his team developed a method of charging smartphones using urine. Allowing urine to pass through microbial fuel cells (MFC), which break down our pee into electricity, the researchers were able to power a mobile phone long enough to send messages, browse the Internet, and make a brief phone call.
While this urine-converting process is still in its infancy and can only produce small amounts of electricity, the researchers and their supporters are optimistic about its potential future value. The Bill and Melissa Gates Foundation—who has funded further improvements on this technology—hopes that with pee-powered smartphones, we can expect a more sanitized and energy-efficient future.
5 Urine-Powered Cars
In the past decade, alternative cars—those that run on fuels like hydrogen rather than fossil fuel—caught the public’s eye, with big car companies parading the possibility of a future of low cost vehicles running on fewer pollutants. However, alternative cars seem to always encounter problems that hinder them from even making it to the market. While the natural gas is abundant in our universe and can be derived from water, it’s difficult to make hydrogen in large enough quantities because of the energy required to do so.
To solve this, Dr. Gerardine Botte of Ohio University devised an electrolyzer that can extract hydrogen from urine using lesser energy. With this technology, Dr, Botte had achieved the potential to power cars using hydrogen from our pee. She explains that, because hydrogen is less bound to urine than it is to water, her devise only requires 0.37 volts of energy—or less than half the energy of an AA battery—to extract it from urea. Water, on the other hand, requires a significantly more powerful energy at 1.23 volts for its hydrogen to be separated. With the tiny amount of energy needed to separate hydrogen from urea and our urine supply of 64 ounces per person, a future of vehicles running on bladder power is not far from the impossible.
4 Brain Cells From Urine
Contrary to popular belief, the adult brain does grow new cells. However, neurodegenerative diseases like Parkinson’s disease destroy more brain cells than we create, leading to certain horrible symptoms like dementia and depression. Where can patients of these debilitating diseases acquire new brain cells to function properly? Scientists from China believe they can pee them. Duanqing Pei and his team of scientists reported that human urine can be used to grow new brain cells.
In their study, researchers extracted the cells from urine samples of three different donors and converted them into neural progenitors, immature brain cells that eventually turn into either glial cells or neurons. The cells were then grown and reprogrammed into different brain cells, some of which were made into actual mature neurons that were able to produce nervous impulses. Other cells were grown to become supportive glial cells like astrocytes and oligodendrocytes. These cultivated brain cells were then transplanted into the nervous systems of newborn rats. A month after the transplant, the brain cells were still seen to be alive and active, though their integration with the existing circuitry of the rat’s brain is still under study.
The biggest benefit of this method is its ethical advantages. Presently, scientists are considering embryonic cells for the treatment of neurodegenerative disorders, but many pro-life groups are opposed to using them. With this new method, scientists can just take urine samples from donors or patients. When this method is improved, we could have better and faster treatment for neurodegenerative disorders that is simple, effective, and ethical.
3 Rocket Fuel
There’s a chance our next trip to space will be potty-powered, as scientists from Radboud University in the Netherlands have developed a way to turn urine into rocket fuel. Microbiologist Mike Jetten says that a type of bacteria that grows and survives without oxygen can convert urine’s ammonia into hydrazine, a type of rocket fuel.
The researchers say that the anaerobic ammonium oxidizing (“annamox”) bacteria are responsible for this amazing feat of nature. While the bacteria’s ability to convert ammonia into hydrazine is already common knowledge among microbiologists, the complex processes involved in the conversion were only figured out recently by Jetten and his team, opening the possibility for a practical use of the bacteria. Their discovery encourages space programs to incorporate the use of the magnificent microbe in our future missions to space. With millions of gallons of ammonia produced every single day from bathroom breaks, the scientists are hopeful to efficiently produce huge quantities of rocket fuel from our urine.
Because space programs like NASA continually suffer from immense budget cuts, which can hinder ground-breaking space missions, looking into this golden idea of turning urine to rocket fuel may be the answer to more cost-effective trips to the last frontier.
2 Pig Pee Plastic
Pig urine is currently Denmark’s most disgusting dilemma. The country’s 20 million pigs produce gallons and gallons of urine per day and the environment isn’t too thrilled about it. Fortunately, a company named Agroplast offers a unique solution to this smelly situation. While we really don’t want the words “pig urine” and “plastic spoons” to ever be combined, Agroplast plans on doing exactly that. The Denmark-based company aims to minimize the hassles of pig pee pollution by turning the compounds of urine into plastic precursors to be used in spoons and plates. Because pig urine in itself has no use and is a financial burden to dispose, plastic made from the substance becomes a very attractive solution to the growing pollution caused by pig urine.
Bioplastics—plastic material made from biomass sources—aren’t a new concept. People have been creating them for years from vegetable oil, corn starch, and plant cellulose. However, bioplastics have proven to be more expensive to produce than those made from fossil fuel. Agroplast claims that, unlike other bioplastics, turning pig pee into plastic would cost one-third less to produce than fossil fuel plastics.
1 Self-Healing Rubber
Broken toys and flat tires are but a few shortcomings of using rubber. It’s a conveniently stretchy and soft material that can be molded into various uses, but when exposed to certain circumstances like heat, it breaks easily. Inspired to solve these deficiencies, French physicist Ludwik Liebler turned to urine to create an amazing invention pulled straight out of sci-fi—rubber that heals itself.
This amazing material is created by combining urea and vegetable oil. When snapped into two, this distinct rubber can be simply stuck back together, immediately returning to its original. Liebler says that the secret is the fatty acids of the vegetable oil and their reaction to urea, creating a material made of a non-uniform molecular system that doesn’t crystallize and become rigid.
The possible uses of this material are endless. Once nothing more than a science fantasy, self-healing objects such sneakers, gloves, wallets, and tires made of this magical substance may actually be the next ground-breaking leap in technology. Because urine and vegetable oil are renewable and easily accessible, mass production of this wonder material won’t be much of a problem. As the French chemical company Arkema has recently adopted this innovation, we can actually aspire to have self-repairing stuff in the near future.
Emerging technology on Nanotechnology
I
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INTRODUCTION
|
Nanotechnology; the
creation and use of materials or devices at extremely small scales. These
materials or devices fall in the range of 1 to 100 nanometers (nm). One nm is
equal to one-billionth of a meter (.000000001 m), which is about 50,000 times
smaller than the diameter of a human hair. Scientists refer to the dimensional
range of 1 to 100 nm as the nanoscale, and materials at this scale are called
nanocrystals or nanomaterials.
The nanoscale is unique
because nothing solid can be made any smaller. It is also unique because many
of the mechanisms of the biological and physical world operate on length scales
from 0.1 to 100 nm. At these dimensions materials exhibit different physical
properties; thus scientists expect that many novel effects at the nanoscale
will be discovered and used for breakthrough technologies.
A number of important
breakthroughs have already occurred in nanotechnology. These developments are
found in products used throughout the world. Some examples are catalytic
converters in automobiles that help remove air pollutants, devices in computers
that read from and write to the hard disk, certain sunscreens and cosmetics
that transparently block harmful radiation from the Sun, and special coatings
for sports clothes and gear that help improve the gear and possibly enhance the
athlete’s performance. Still, many scientists, engineers, and technologists
believe they have only scratched the surface of nanotechnology’s potential.
Nanotechnology is in its
infancy, and no one can predict with accuracy what will result from the full
flowering of the field over the next several decades. Many scientists believe
it can be said with confidence, however, that nanotechnology will have a major
impact on medicine and health care; energy production and conservation;
environmental cleanup and protection; electronics, computers, and sensors; and
world security and defense.
II
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WHAT IS
NANOTECHNOLOGY?
|
To grasp the size of the
nanoscale, consider the diameter of an atom, the basic building block of
matter. The hydrogen atom, one of the smallest naturally occurring atoms, is
only 0.1 nm in diameter. In fact, nearly all atoms are roughly 0.1 nm in size,
too small to be seen by human eyes. Atoms bond together to form molecules, the
smallest part of a chemical compound. Molecules that consist of about 30 atoms
are only about 1 nm in diameter. Molecules, in turn, compose cells, the basic
units of life. Human cells range from 5,000 to 200,000 nm in size, which means
that they are larger than the nanoscale. However, the proteins that carry out
the internal operations of the cell are just 3 to 20 nm in size and so have
nanoscale dimensions. Viruses that attack human cells are about 10 to 200 nm,
and the molecules in drugs used to fight viruses are less than 5 nm in size.
The possibility of
building new materials and devices that operate at the same scale as the basic
functions of nature explains why so much attention is being devoted to the
world below 100 nm. But 100 nm is not some arbitrary dividing line. This is the
length at which special properties have been observed in materials—properties
that are profoundly different at the nanoscale.
Human beings have
actually known about these special properties for some time, although they did
not understand why they occurred. Glassworkers in the Middle Ages, for example,
knew that by breaking down gold into extremely small particles and sprinkling
these fine particles into glass the gold would change in color from yellow to
blue or green or red, depending on the size of the particle. They used these
particles to help create the beautiful stained glass windows found in
cathedrals throughout Europe, such as the cathedral of Notre Dame in Paris,
France. These glassworkers did not realize it at the time, but they had created
gold nanocrystals. At scales above 100 nm gold appears yellow, but at scales
below 100 nm it exhibits other colors.
Nanotechnologists are
intrigued by the possibility of creating humanmade devices at the molecular, or
nanoscale, level. That is why the field is sometimes called molecular
nanotechnology. Some nanotechnologists are also aiming for these devices to
self-replicate—that is, to simultaneously carry out their function and increase
their number, just as living organisms do. To some early proponents of the
field, this aspect of nanotechnology is the most important. If tiny functional
units could be assembled at the molecular level and made to self-replicate
under controlled conditions, tremendous efficiencies could be realized.
However, many scientists doubt the possibility of self-replicating
nanostructures.
III
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APPROACHES TO
NANOTECHNOLOGY
|
Scientists are currently
experimenting with two approaches to making structures or devices at the scale
of 1 to 100 nm. These methods are called the top-down approach and the
bottom-up approach.
A
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Top-down Approach
|
In the top-down process,
technologists start with a bulk material and carve out a smaller structure from
it. This is the process commonly used today to create computer chips, the tiny
memory and logic units, also known as integrated circuits that operate
computers. To produce a computer chip, thin films of materials, known as a
mask, are deposited on a silicon wafer, and the unneeded portions are etched
away. Almost all of today’s commercial computer chips are larger than 100 nm.
However, the technology to create ever smaller and faster computer chips has
already gone below 100 nm. Smaller and faster chips will enable computers to
become even smaller and to perform many more functions more quickly.
The top-down approach,
which is sometimes called microfabrication or nanofabrication, uses advanced
lithographic techniques to create structures the size of or smaller than
current commercial computer chips. These advanced lithographic techniques
include optical lithography and electron-beam (e-beam) lithography. Optical
lithography currently can be used to produce structures as small as 100 nm, and
efforts are being made to create even smaller features using this technique.
E-beam lithography can create structures as small as 20 nm. However, e-beam
lithography is not suitable for large-scale production because it is too
expensive. Already the cost of building fabrication facilities for producing
computer chips using optical lithography approaches several billion dollars.
Ultimately, the top-down
approach to producing nanostructures is not only likely to be too costly but
also technically impossible. Assembling computer chips or other materials at
the nanoscale is unworkable for a fundamental reason. To reduce a material in a
specifically designed way, the tool that is used to do the work must have a dimension
or precision that is finer than the piece to be reduced. Thus, a machine tool
must have a cutting edge finer than the finest detail to be cut. Likewise the
lithographic mask used to etch away the locations on a silicon wafer must have
a precision in its construction finer than the material to be removed. At the
nanoscale, where the material to be removed could be a single molecule or atom,
it is impossible to meet this condition.
B
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Bottom-up Approach
|
As a result, scientists
have become interested in another vastly different approach to creating
structures at the nanoscale, known as the bottom-up approach. The bottom-up
approach involves the manipulation of atoms and molecules to form
nanostructures. The bottom-up approach avoids the problem of having to create
an ever-finer method of reducing material to the nanoscale size. Instead,
nanostructures would be assembled atom by atom and molecule by molecule, from
the atomic level up, just as occurs in nature. However, assembly at this scale
has its own challenges.
In school, children
learn about some of these challenges when they study the random Brownian motion
seen in particles suspended in liquids such as water. The particles themselves
are not moving. Rather, the water molecules that surround the particles are
constantly in motion, and this motion causes the molecules to strike the
particles at random. Atoms also exhibit such random motion due to their kinetic
energy. Temperature and the strength of the bonds holding the atoms in place
determine the degree to which atoms move. Even in solids at room
temperature—the chair you may be sitting on, for example—atoms move about in a
process called diffusion. This ability of atoms to move about increases as a
substance changes from solid to liquid to gas. If scientists and engineers are
to successfully assemble at the atomic scale, they must have the means to
overcome this type of behavior.
A clear example of such
a challenge occurred in 1990 when scientists from the International Business
Machines Corporation (IBM) used a scanning probe microscope tip to assemble
individual xenon atoms so that they formed the letters IBM on a nickel
surface. To prevent the atoms from moving away from their assigned locations,
the nickel surface was cooled to temperatures close to absolute zero, the
lowest temperature theoretically possible and characterized by the complete
absence of heat. (Absolute zero is -273.15°C [-459.67°F].) At this low
temperature, the atoms possessed very little kinetic energy and were
essentially frozen.
Achieving this
temperature, however, is impractical and uneconomical for the operation of
commercial devices. Nevertheless, the ability of scientists to manipulate atoms
was one of the first indications that the bottom-up approach might work. It
also signaled the emergence of nanotechnology as an experimental science.
IV
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THE EMERGENCE OF
NANOTECHNOLOGY
|
The concept of
nanotechnology originated with American physicist Richard P. Feynman. In a talk
to the American Physical Society in December 1959, entitled “There’s Plenty of
Room at the Bottom: An Invitation to Enter a New Field of Physics,” Feynman
provided examples of the benefits to be obtained by producing ultrasmall
structures. Feynman calculated that the entire content of Encyclopædia
Britannica could be reduced to fit on the head of a pin, and he estimated
that all of printed human knowledge could be reduced to fit on 35 normal-sized
pages.
Although he did not coin
the term nanotechnology, the visionary Feynman predicted key aspects of today’s
nanotechnology, such as the importance of advanced microscopes and the
development of new fabrication methods. He also emphasized the importance of
combining the knowledge, tools, and methodologies used by physicists, chemists,
and biologists. He pointed to the natural world as an example of how much
information and function can be packed into a tiny volume. A single cell, for
example, can move, perform biochemical processes, and contains within its DNA
molecule the complete knowledge of the design and function of the complex
organism of which it is part.
Feynman believed the
creation of nanoscale devices was possible within the boundaries set by the
laws of physics. He specifically cited the possibility of atom-by-atom
assembly—that is, building a structure (a molecule or a device) from individual
atoms precisely joined by chemical forces. This possibility led to the concept
of a “universal assembler,” a robotic device at nanoscale dimensions that could
automatically assemble atoms to create molecules of the desired chemical
compounds. Such a device, for example, could assemble carbon atoms to form
low-cost, large diamonds, a potentially important industrial material, now used
only in limited quantities due to the high cost of mining and synthesis. Such
synthetic diamonds could have many industrial and consumer applications because
they are lightweight and yet extremely hard, and are electrically insulating
but excellent conductors of heat. The idea of a nanoscale robotic assembler
continues to be promoted by some researchers, although there is considerable
debate whether such a device is indeed possible within the known laws of
chemistry, physics, and thermodynamics.
Nanotechnology began
being promoted as a key component of future technology in the late 1970s. The
term nanotechnology was first used in 1974 by Japanese scientist Norio
Taniguchi in a paper titled “On the Basic Concept of Nanotechnology.” However,
the term was also used by American engineer K. Eric Drexler in the book Engines
of Creation (1986), which had a greater impact and helped accelerate the
growth of the field. By this time, major breakthroughs had been achieved in
industry, such as the formation of nanoparticle catalysts made of nonreactive
metals and used in catalytic converters found in automobiles. These catalysts
chemically reduced noxious nitrogen oxides to benign nitrogen and
simultaneously oxidized poisonous carbon monoxide to form carbon dioxide.
A
|
The Tools of
Nanotechnology
|
The scientific community
began serious work in nanoscience when tools became available in the late 1970s
and early 1980s—first to probe and later to manipulate and control materials
and systems at the nanoscale. These tools include the transmission electron
microscope (TEM), the atomic force microscope (AFM), and the scanning tunneling
microscope (STM). See also Microscope.
A1
|
Transmission Electron
Microscope (TEM)
|
The TEM uses a
high-energy electron beam to probe material with a sample thickness of less
than 100 nm. The electron beam is directed onto the object to be magnified.
Some of the electrons are absorbed by or bounce off the object, while others
pass through the object and form a magnified image of the material. A
photographic plate, fluorescent screen, or digital camera placed behind the
material records the magnified image. TEMs can magnify an object up to 30
million times. By contrast a conventional optical microscope can magnify
objects up to 1,000 times. TEMs are suitable for imaging objects with
dimensions of less than 100 nm, and they yield information on the size of the
nanostructure, its composition, and its crystal structures.
The TEM is a popular and
powerful instrument within the nanoscience community. Most of the images
published in scientific journals on nanocrystals found in semiconductors were
recorded with this instrument. TEMs can easily visualize individual atoms
within semiconductor nanocrystals.
A2
|
Atomic Force
Microscope (AFM)
|
An AFM uses a tiny
silicon tip, usually less than 100 nm in diameter, as a probe to create an
image of a sample material. As the silicon probe moves along the surface of the
sample, the electrons of the atoms in the sample repel the electrons in the
probe. The AFM adjusts the height of the probe to keep the force on the sample
constant. A sensing mechanism records the up-and-down movements of the probe
and feeds the data into a computer, which creates a three-dimensional image of
the surface of the sample. Thus, the exact surface topography can be recorded
with precise height information, and individual atoms in the surface can be
imaged. The lateral resolution of this technique, however, is sometimes poor.
A3
|
Scanning Tunneling
Microscope (STM)
|
An STM uses a tiny
probe, the tip of which can be as small as a single atom, to scan an object. An
STM takes advantage of a wavelike property of electrons called tunneling.
Tunneling allows electrons emitted from the probe of the microscope to
penetrate, or tunnel into, the surface of the object being examined. The rate
at which the electrons tunnel from the probe to the surface is related to the
distance between the probe and the surface. These moving electrons generate a
tiny electric current that the STM measures. The STM constantly adjusts the
height of the probe to keep the current constant. By tracking how the height of
the probe changes as the probe moves over the surface, scientists can get a
detailed map of the surface. The map can be so detailed that individual atoms
on the surface are visible.
B
|
Manipulating Atoms
|
In addition to imaging,
AFM and STM are also useful for manipulating nanostructures. In this regard,
the tips resemble “arms” that can be used to manipulate individual atoms. For
example, not only did scientists at IBM move and align individual atoms on a
flat surface so that the atoms spelled IBM, but also they used an STM to
position 48 iron atoms into a circular structure, where interesting phenomenon
could be visually inspected. This manipulation was only possible at extremely
low temperatures.
Although the AFM and STM
are capable of moving atoms and individual nanostructures, the process is very
slow and time-consuming. Scientists hope to develop this technique further by
using massive arrays of scanning tips instead of just using one. Such arrays
could help speed up the manipulation of atoms, although it would also require
extensive micro- and nanofabrication.
C
|
Synthesizing Carbon
Molecules and Other Developments
|
Several other
developments in the 1980s and 1990s stimulated interest in the potential of
nanotechnology. In 1985 chemists at Rice University in Houston, Texas, led by
Richard E. Smalley, discovered they could make perfectly round carbon molecules
consisting of 60 carbon atoms. The scientists nicknamed these synthetic
molecules buckyballs, or fullerenes, for their resemblance to the geodesic
domes designed by architect R. Buckminster Fuller. Being able to make synthetic
carbon was exciting for several reasons. Carbon is the fundamental building
block of material in living things. Carbon atoms also combine easily with other
atoms and can form more compounds than any other element. Carbon atoms also
form strong bonds, which can help form strong but relatively lightweight
materials. But the special properties of the synthetic buckyballs were even
more exciting. When combined with other substances buckyballs could act in a
variety of ways. They could be conductors of electricity, insulators,
semiconductors, or superconductors. Their possible applications seemed immense.
Then in 1991 Japanese
physicist Sumio Iijima published a widely noticed report that appeared to build
on the buckyball discovery. While studying fullerenes, Iijima reported finding
a tubular version known as a carbon nanotube, a thin, extraordinarily stiff
form of carbon that has been described as “the strongest material that will
ever be made.” In 1993 two researchers working independently—Iijima in Japan
and American physicist Donald S. Bethune of the IBM Almaden Research Center in
California—developed a nanotube that was only a single atom thick. The
breakthrough had enormous implications. The use of these so-called single-wall
nanotubes as electronic circuits, for example, could lead to computer chips
containing billions of transistors, as compared with the 42 million transistors
that fit on current chips. Computers could become ever smaller, faster, and
more powerful. And that was only one of a variety of possible applications.
The increasing focus of
the scientific community on the nanoscale led the United States government in
1999 to identify nanotechnology as a research priority. In 2000 President Bill
Clinton announced the National Nanotechnology Initiative (NNI) with a budget of
$442 million. Shortly thereafter, the leading industrial nations of the world
followed the U.S. lead. By 2003 the United States, the European Union (EU), and
Japan had major nanotechnology initiatives with funding levels approaching $1
billion per year to promote the development of the field. In addition, other
countries throughout the world launched nanotechnology initiatives with
aggregate funding at a similar level to the three leading government
initiatives. In the U.S. budget approved in 2003, $3.7 billion was approved for
nanotechnology research over the next four years.
In addition to the
support of federal governments, state governments also became active in support
of nanotechnology. Examples in the United States include the New York
Nanotechnology Initiative, the California Nanosystems Institute, Pennsylvania’s
Nanotechnology Institute, and the Texas Nanotechnology Initiative. An international
example is NanoBioNet of the state of Saarland, Germany.
By 2003 significant
commercial products had already been developed based on nanotechnologies. The
devices on computers known as read-write heads, which read data from a computer
hard disk and also write data to the disk, were built from multilayer
nanometer-thick film. These films increased the sensitivity of the read-write
heads so that many more bits of data can be packed on the surface of the hard
disks. Consequently, the memory capacity found in modern personal computers
dramatically increased, and relatively inexpensive 60-gigabyte hard disks
became available in competitively priced computers.
Another nanotechnology
product line was nanoparticle formulations of zinc or titanium oxides that
absorb harmful ultraviolet radiation from the Sun but are invisible to the eye.
This technology has enabled cosmetic companies to offer skin protection in
their products without compromising appearance. The usually white skin creams
become transparent upon application because the nanoparticles are too small to
scatter light. Nanocoating technology on clothes has yielded the most
stain-resistant clothes ever produced. Olympic-level swimmers have been aided
in setting many new world records by using swimsuits with clothing fibers
bonded to hydrophobic (not compatible with water) molecules. These nanocoated
swimsuits create less friction with water so swimmers can swim faster.
In the early 21st
century corporations began to identify nanoscience and nanotechnology as a
field of development unto itself with many common concepts and approaches that
could impact broadly across multiple product lines. It became common for major
high-tech corporations to have a specific manager or leading scientist assigned
to the development of corporate nanotechnology strategy, research, and
development. In addition to the larger corporations, the field also began to
yield many small start-up companies. As of 2003 most of these companies were
involved in nanomaterials production, simple nanodevice fabrication, and the
production of tools used to research and manufacture at the nanoscale. In the
investment community, an increasing number of venture capitalist enterprises
began to follow nanotechnology closely, and the first funds devoted solely to
investment in nanotechnology companies were created.
V
|
CHALLENGES CONFRONTING
NANOTECHNOLOGY
|
A major challenge facing
nanotechnology is how to make a desired nanostructure and then integrate it
into a fully functional system visible to the human eye. This requires creating
an interface between structures built at the nanometer scale and structures
built at the micrometer scale. A common strategy is to use the so-called
“top-down meets bottom-up” approach. This approach involves making a
nanostructure with tools that operate at the nanoscale, organizing the
nanostructures with certain assembly techniques, and then interfacing with the
world at the micrometer scale by using a top-down nanofabrication process.
However, technical
barriers exist on the road toward this holy grail of nanotechnology. For
example, the bottom-up approach generally yields nanocrystals of 1 nm, a dimension
that is too small for current nanofabrication techniques to interact with. As a
result, interfacing a nanocrystal with the outside world is a highly complex
and expensive process. A novel procedure must be developed to overcome this
barrier before many of the synthetic nanostructures can become part of
mainstream industrial applications.
Also, as the size of the
nanostructure gets increasingly thinner, the surface area of the material
increases dramatically in relation to the total volume of the structure. This
benefits applications that require a big surface area, but for other
applications this is less desirable. For example, it is undesirable to have a
relatively large surface area when carbon nanotubes are used as an electrical
device, such as a transistor. This large surface area tends to increase the
possibility that other unwanted layers of molecules will adhere to the surface,
harming the electrical performance of the nanotube devices. Scientists are
tackling this issue to improve the reliability of many nanostructure-based
electronic devices.
Another important issue
relates to the fact that the properties of nanocrystals are extremely sensitive
to their size, composition, and surface properties. Any tiny change can result
in dramatically different physical properties. Preventing such changes requires
high precision in the development of nanostructure synthesis and fabrication.
Only after this is achieved can the reproducibility of nanostructure-based
devices be improved to a satisfactory level. For example, although carbon
nanotubes can be fashioned into high-performance transistors, there is a
significant technical hurdle regarding their composition and structure. Carbon
nanotubes come in two “flavors”; one is metallic and the other is semiconducting.
The semiconducting flavor makes good transistors. However, when these carbon
nanotubes are produced, mixtures of metallic and semiconducting tubes are
entangled together and so do not make good transistors. There are two possible
solutions for this problem. One is to develop a precise synthetic methodology
that generates only semiconductor nanotubes. The other is to develop ways to
separate the two types of nanotubes. Both strategies are being researched in
labs worldwide.
VI
|
FUTURE IMPACT OF
NANOTECHNOLOGY
|
Nanotechnology is
expected to have a variety of economic, social, environmental, and national
security impacts. In 2000 the National Science Foundation began working with
the National Nanotechnology Initiative (NNI) to address nanotechnology’s
possible impacts and to propose ways of minimizing any undesirable
consequences.
For example, nanotechnology
breakthroughs may result in the loss of some jobs. Just as the development of
the automobile destroyed the markets for the many products associated with
horse-based transportation and led to the loss of many jobs, transformative
products based on nanotechnology will inevitably lead to a similar result in
some contemporary industries. Examples of at-risk occupations are jobs
manufacturing conventional televisions. Nanotechnology-based field-emission or
liquid-crystal display (LCD), flat-panel TVs will likely make those jobs
obsolete. These new types of televisions also promise to radically improve
picture quality. In field-emission TVs, for example, each pixel (picture
element) is composed of a sharp tip that emits electrons at very high currents
across a small potential gap into a phosphor for red, green, or blue. The
pixels are brighter, and unlike LCDs that lose clarity in sunlight,
field-emission TVs retain clarity in bright sunlight. Field-emission TVs use
much less energy than conventional TVs. They can be made very thin—less than a
millimeter—although actual commercial devices will probably have a bit more
heft for structural stability and ruggedness. Samsung claims it will be
releasing the first commercial model, based on carbon nanotube emitters, by
early 2004.
Other potential job
losses could be those of supermarket cashiers if nanotechnology-based,
flexible, thin-film computers housed in plastic product wrappings enable
all-at-once checkout. Supermarket customers could simply wheel their carts
through a detection gateway, similar in shape to the magnetic security systems
found at the exits of stores today. As with any transformative technology,
however, nanotechnology can also be expected to create many new jobs.
The societal impacts from
nanotechnology-based advances in human health care may also be large. A
ten-year increase in human life expectancy in the United States due to
nanotechnology advances would have a significant impact on Social Security and
retirement plans. As in the fields of biotechnology and genomics, certain
development paths in nanotechnology are likely to have ethical implications.
Nanomaterials could also
have adverse environmental impacts. Proper regulation should be in place to
minimize any harmful effects. Because nanomaterials are invisible to the human
eye, extra caution must be taken to avoid releasing these particles into the
environment. Some preliminary studies point to possible carcinogenic
(cancer-causing) properties of carbon nanotubes. Although these studies need to
be confirmed, many scientists consider it prudent now to take measures to
prevent any potential hazard that these nanostructures may pose. However, the
vast majority of nanotechnology-based products will contain nanomaterials bound
together with other materials or components, rather than free-floating
nano-sized objects, and will therefore not pose such a risk.
At the same time,
nanotechnology breakthroughs are expected to have many environmental benefits
such as reducing the emission of air pollutants and cleaning up oil spills. The
large surface areas of nanomaterials give them a significant capacity to absorb
various chemicals. Already, researchers at Pacific Northwestern National
Laboratory in Richland, Washington, part of the U.S. Department of Energy, have
used a porous silica matrix with a specially functionalized surface to remove
lead and mercury from water supplies.
Finally, nanotechnology
can be expected to have national security uses that could both improve military
forces and allow for better monitoring of peace and inspection agreements.
Efforts to prevent the proliferation of nuclear weapons or to detect the
existence of biological and chemical weapons, for example, could be improved
with nanotech devices.
VII
|
NANOTECHNOLOGY RESEARCH
|
Major centers of
nanoscience and nanotechnology research are found at universities and national
laboratories throughout the world. Many specialize in particular aspects of the
field. Centers in nanoelectronics and photonics (the study of the properties of
light) are found at the Albany Institute of Nanotechnology in Albany, New York;
Cornell University in Ithaca, New York; the University of California at Los
Angeles (UCLA); and Columbia University in New York City. In addition, Cornell
hosts the Nanobiotechnology Center.
Universities with
departments specializing in nanopatterning and assembly include Northwestern
University in Evanston, Illinois, and the Massachusetts Institute of Technology
(MIT) in Cambridge. Biological and environmental-based studies of nanoscience
exist at the University of Pennsylvania in Philadelphia, Rice University in
Houston, and the University of Michigan in Ann Arbor. Studies in nanomaterials
are taking place at the University of California at Berkeley and the University
of Illinois in Urbana-Champaign. Other university-affiliated departments
engaged in nanotechnology research include the Nanotechnology Center at Purdue
University in West Lafayette, Indiana; the University of South Carolina
NanoCenter in Columbia; the Nanomanufacturing Research Institute at
Northeastern University in Boston, Massachusetts; and the Center for Nano
Science and Technology at Notre Dame University in South Bend, Indiana. By 2003
more than 100 U.S. universities had departments or research institutes
specializing in nanotechnology.
Other major research
efforts are taking place at national laboratories, such as the Center for
Integrated Nanotechnologies at Sandia National Laboratories in Albuquerque and
at Los Alamos National Laboratory, both in New Mexico; the Center for Nanophase
Materials Sciences at Oak Ridge National Laboratory in Tennessee; the Center
for Functional Nanomaterials at Brookhaven National Laboratory in Upton, New
York; the Center for Nanoscale Materials at Argonne National Laboratory outside
Chicago, Illinois; and the Molecular Foundry at the Lawrence Berkeley National
Laboratory in Berkeley, California.
Internationally, the
Max-Planck Institutes in Germany, the Centre National de la Recherche
Scientifique (CNRS) in France, and the National Institute of Advanced
Industrial Science and Technology of Japan are all engaged in nanotechnology
research.
Contributed By:
Peidong Yang
David E. Luzzi
Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation.
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