UNIVERSITY INSTITUTE OF ENGINEERING AND TECHNOLOGY, KURUKSHETRA

UNIVERSITY, KURUKSHETRA

A

REPORT ON

NANOTECHNOLOGY

YEAR : 2012

SUBMITTED TO: SUBMITTED BY:

DR. C.C. Tripathi Puneet Dubey

HOD, ECE Deptt. 2508023

UIET, KUK ECE-A (8th sem)

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TABLE OF FIGURES

FIGURE NAME PAGE NO.

Nanofly 5

Nanoscale 7

Nanodevice 12

Gold particles carrying anticancer drugs 13

Electron micrograph of typical silicon nanocomposite 15

Quantum dots 16

Nanocrystals 16

Replicator 22

Assembler 23

Components of MEMS 25

Micromachined electro-statically-actuated micromotor 26

Micromachined resonator fabricated by the MNX 27

Types of Hazards to Humans 28

Hazards to Environment 31

Hazards to aquatic life 31

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TABLE OF CONTENTS

NAME PAGE NO.

Abstract 4

Introduction to Nanotechnology 5

How small is Nanoscale 6

Present work in Nanotechnology 12

Nanotechnology Products 15

Future of Nanotechnology 21

Future Products 23

What is MEMS 24

Hazards of Nanotechnology 28

Conclusion 32

Bibliography 33

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ABSTRACT

Nanotechnology is the study of manipulating matter on an atomic and molecular scale.

Generally, nanotechnology deals with developing materials, devices, or other structures

possessing at least one dimension sized from 1 to 100 nanometres. Quantum

mechanical effects are important at this quantum-realm scale.

Nanotechnology is very diverse, ranging from extensions of conventional device physics to

completely new approaches based upon molecular self-assembly, from developing new

materials with dimensions on the Nano scale to direct control of matter on the atomic scale.

Nanotechnology entails the application of fields of science as diverse as surface

science, organic chemistry, molecular biology, semiconductor physics, micro fabrication, etc.

There is much debate on the future implications of nanotechnology. Nanotechnology may be

able to create many new materials and devices with a vast range of applications, such as

in medicine, electronics, biomaterials and energy production. On the other hand,

nanotechnology raises many of the same issues as any new technology, including concerns

about the toxicity and environmental impact of nanomaterials,[1] and their potential effects on

global economics, as well as speculation about various doomsday scenarios. These concerns

have led to a debate among advocacy groups and governments on whether special regulation

of nanotechnology is warranted.

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INTRODUCTION TO NANOTECHNOLOGY:-

One of the biggest scientific trends of the 21st century has been centered on something

incredibly small: nanotechnology. But what is nanotechnology? That is the most difficult

question to answer, even though it’s all over the news these days. The crux of the problem is

that it is beyond the understanding of most people. Unless we have studied it extensively in

university we won’t know what a quantum dot is. We will need to know the underlying

science that drives it, the tools we use to apply it, and the potential benefits and dangers of it.

Nanotechnology is a broad term for

the application of scientific

understanding towards fabricating

devices and materials at the

nanometer scale. Nanotechnology

takes its name from a unit called

nanometre-nm, which means it’s

the one billionth of a meter. [1nm

= nanometer (1,000,000,000 nm

per m, or 10 -

9m)].Nanotechnology is primarily characterized by its overall dimension: the Nano-world.

The Nano-world exists at the level of single molecules and atoms-the size of a millionth of a

millimetre. Nanotechnology involves building sophisticated products from the molecular

scale. As the molecule is the smallest particle of matter that exists independently, it cannot be

ruled by any of us, but the technologists have started ruling the same understanding the

molecular world as a tough process. This kind of molecular manufacturing will in fact result

in high quality, smart and intelligent products that are 100% efficient, produced at low cost

with little environmental impact. Nanotechnology is expected to have an enormous potential

for innovation because it may create effects which have not yet been feasible with any other

technologies. The far reaching possibilities of nanotechnology development, which are

currently being assessed according to feasibility, find their echo in partly extreme judgments

of the technology. The specific characteristics of this dimension are that nano-particles show

a completely different behaviour to their larger, coarser pendants. The relatively big specific

surface of nano-particles usually leads to an increase in their chemical reactivity and catalytic

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Fig: nanofly

activity. The relatively small amount of atoms within nano-particles offsets the quasi-

continuous solid state of the particle, leading to new, deviating, optical, electrical and

magnetic features. From these basic features and characteristics of Nano-technology, a

number of possible positive and problematic (negative) effects can be derived.

Nanotechnology is very diverse, ranging from extensions of conventional device physics to

completely new approaches based upon molecular self-assembly, from developing new

materials with dimensions on the nanoscale to direct control of matter on the atomic scale.

Nanotechnology entails the application of fields of science as diverse as surface

science, organic chemistry, molecular biology, semiconductor physics, microfabrication, etc.

"In not too many decades we should have a manufacturing technology able to: Build

products with almost every atom in the right place; Do so inexpensively; Make most

arrangements of atoms consistent with physical law. Often called nanotechnology,

molecular nanotechnology or molecular manufacturing, it will let us make most

products lighter, stronger, smarter, cheaper, cleaner and more

precise." Nanotechnology: It's a Small, Small, Small, Small World By Ralph C. Merkle,

Ph.D.

Many materials, once they are individually reduced below 100 nanometres, begin displaying

a set of unique characteristics based on quantum mechanical forces that are exhibited at the

level. Due to these quantum mechanical effects, materials may become more conducting, be

able to transfer heat better, or have modified mechanical properties.

Nanotechnology is a recently emerging and rapidly growing field whose dynamics and

prospects pose many great challenges not only to scientists and engineers but also to society

at large.

HOW SMALL IS NANOSCALE:-

To give an idea of the size of a nanometre (nm) here are some examples:

• Typical red blood cell, 7000 nm in width, 2000 nm in height

• Common cold virus, 25 nm

• Width of DNA molecule, 2 nm

• Silicon atom, 0.2 nm

Nanotechnology inhabits the world of cells, viruses and even DNA. For example, by volume,

a nanoparticle 2 nm in size would be over 10 billion times smaller than a red blood cell. To 6

put this into context if the nano particle in question was the size of a person, then that blood

cell would be approximately the size of the City of London. This means that when

dealing with the risks, the effect on cells should be considered.

Let's start BIG, with something you can get your hands on (so to speak):

A meter is about the distance from the tip of your nose to the end of your hand (1 meter =

3.28 feet).

One thousandth of that is a millimeter.

Now take one thousandth of that, and you have a micron: a thousandth of a thousandth of a

meter. Put another way: a micron is a millionth of a meter, which is the scale that is relevant

to - for instance - building computers, computer memory, and logic devices.

Now, let's go smaller, to the nanometer: 

A nanometer is one thousandth of a micron, and a thousandth of a millionth of a meter (a

billionth of a meter). Imagine: one billion nanometres in a meter.

 

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Fig: Nanoscale

Another perspective: a nanometer is about the width of six bonded carbon atoms, and

approximately 40,000 are needed to equal the width of an average human hair. 

Another way to visualize a nanometer: 

1 inch = 25,400,000 nanometers 

Red blood cells are ~7,000 nm in diameter, and ~2000 nm in height

White blood cells are ~10,000 nm in diameter

A virus is ~100 nm

A hydrogen atom is .1 nm

Nanoparticles range from 1 to 100 nm

Fullerenes (C60 / Buckyballs) are 1 nm

Quantum Dots (of CdSe) are 8 nm

Dendrimers are ~10 nm

DNA (width) is 2 nm

Proteins range from 5 to 50 nm

Viruses range from 75 to 100 nm

Bacteria range from 1,000 to 10,000 nm

For our purposes, nanometers pertain to science, technology, manufacturing, chemistry,

health sciences, materials science, space programs, and engineering.

Nanotechnology is the understanding and control of matter at dimensions of roughly 1 to 100

nanometers, where unique phenomena enable novel applications. Encompassing nanoscale

science, engineering and technology, nanotechnology involves imaging, measuring,

modeling, and manipulating matter at this length scale. 

At the nanoscale, the physical, chemical, and biological properties of materials differ in

fundamental and valuable ways from the properties of individual atoms and molecules or

bulk matter. Nanotechnology R&D is directed toward understanding and creating improved

materials, devices, and systems that exploit these new properties. 

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Somethings that become Possible with Mature Nanotechnology :

Nearly free consumer products

PC's billions of times faster than today

Safe and affordable space travel

Virtual end to illness, aging, death

No more pollution and automatic clean-up of existing pollution

End of famine and starvation

Superior education for every child on Earth

Reintroduction of many extinct plants and animals

Terraforming Earth and the Solar System

The following devices and capabilities appear to be both physically possible and

practically realizable: 

• Programmable positioning of reactive molecules with ~0.1 nm precision

• Mechanosynthesis at >106operations/device · second 

• Mechanosynthetic assembly of 1 kg objects in <104 s

• Nanomechanical systems operating at ~109 Hz 

• Logic gates that occupy ~10–26 m3 (~10– 8 m3)

• Logic gates that switch in ~0.1 ns and dissipate <10– 21 J 

• Computers that perform 1016 instructions per second per watt 

• Cooling of cubic-centimeter, ~105 W systems at 300 K 

• Compact 1015 MIPS parallel computing systems 

• Mechanochemical power conversion at >109 W/m3

• Electromechanical power conversion at >1015 W/m3 

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• Macroscopic components with tensile strengths >5×1010 Pa

• Production systems that can double capital stocks in <104 s

Of these capabilities, several are qualitatively novel and others improve on present

engineering practice by one or more orders of magnitude. Each is an aspect or a consequence

of molecular manufacturing.

Assumptions, principles, and some specific recommendations intended to provide a

basis for responsible development of molecular nanotechnology

Development Principles

1. Artificial replicators must not be capable of replication in a natural, uncontrolled

environment.

2. Evolution within the context of a self-replicating manufacturing system is

discouraged.

3. Any replicated information should be error free.

4. MNT device designs should specifically limit proliferation and provide traceability of

any replicating systems.

5. Developers should attempt to consider systematically the environmental consequences

of the technology, and to limit these consequences to intended effects. This requires

significant research on environmental models, risk management, as well as the theory,

mechanisms, and experimental designs for built-in safeguard systems.

6. Industry self-regulation should be designed in whenever possible. Economic

incentives could be provided through discounts on insurance policies for MNT

development organizations that certify Guidelines compliance. Willingness to provide

self-regulation should be one condition for access to advanced forms of the

technology.

7. Distribution of molecular manufacturing development capability should be restricted,

whenever possible, to responsible actors that have agreed to use the Guidelines. No

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such restriction need apply to end products of the development process that satisfy the

Guidelines.

Specific Design Guidelines

1. Any self-replicating device which has sufficient onboard information to describe its

own manufacture should encrypt it such that any replication error will randomize its

blueprint.

2. Encrypted MNT device instruction sets should be utilized to discourage irresponsible

proliferation and piracy.

3. Mutation (autonomous and otherwise) outside of sealed laboratory conditions, should

be discouraged.

4. Replication systems should generate audit trails.

5. MNT device designs should incorporate provisions for built-in safety mechanisms,

such as: 1) absolute dependence on a single artificial fuel source or artificial

"vitamins" that don't exist in any natural environment; 2) making devices that are

dependent on broadcast transmissions for replication or in some cases operation; 3)

routing control signal paths throughout a device, so that subassemblies do not

function independently; 4) programming termination dates into devices, and 5) other

innovations in laboratory or device safety technology developed specifically to

address the potential dangers of MNT.

6. MNT developers should adopt systematic security measures to avoid unplanned

distribution of their designs and technical capabilities.

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PRESENT WORK IN NANOTECHNOLOGY :

This quote from "The Next Big Thing Is Really Small: How Nanotechnology Will Change

The Future Of Your Business" (by Jack Uldrich and Deb Newberry Read our review) sums it

up nicely: 

"This is not to say that nanotechnology is a far-off, fuzzy, futuristic technology. It is not. It

has already established a beachhead in the economy. The clothing industry is starting to feel

the effects of nanotech. Eddie Bauer, for example, is currently using embedded nanoparticles

to create stain-repellent khakis. This seemingly simple innovation will impact not only khaki-

wearers, but dry cleaners, who will find their business declining; detergent makers, who will

find less of their product moving off the shelf; and stain-removal makers, who will

experience a sharp decrease in customers. This modest, fairly low-tech application of

nanotechnology is just the small tip of a vast iceberg--an iceberg that threatens to sink even

the "unsinkable" companies." 

Nanotechnology in medicine research

Nanotechnology is the latest buzzword in the technological circles. Nano particles are tiny in

size and have their own calibrations. Nano particles range between the sizes of 1 to 100

nanometers. They are thousands of times smaller than the breadth of a human hair.

In the field of medicine, nanotechnology is being

used to study DNA molecules. In effect, these

tiny particles form the middle path between

bulky objects and particles of molecular and

12Fig: nanodevice

atomic sizes. Nanochannels are used to study different aspects and structure of the building

blocks of the human body. Cells are stretched and pushed through nanochannels to

understand the working of a single cell. Nano-engineering is used to deliver drugs more

effectively into the body at the cellular level. Massive research is being carried out to study

the behavior of the tiniest particles, with the use of nanotechnology.

Nanotechnology in cancer treatments

Nanotechnology is being considered as the most effective method to cure deadly cancer cells.

Nanoparticles can penetrate into the tiny

cancer cells and cause their destruction.

Nanotechnology is being used to segregate

cancer cells from healthy cells by using

magnetic properties. The nanospheres can be

used to effectively differentiate between

different kinds of cancer cells like leukemia,

breast cancer and prostate cancer. The biggest

benefit of using this cutting-edge technology

is that cancer cells of the smallest concentration can

be identified, which implies early detection of cancer

and successful cure.

Nanotechnology in metallurgy

Metallurgy is the science of creating new materials such as alloys by combining properties of

different metals or making modifications in the existing properties of metals. New metals,

which are fabricated, contain better endurance and strength as compared to individual metals.

Nanotechnology is being effectively used in making modifications at the atomic level to

make materials more effective. Its use is extensive in processes such as catalysis.

Nanotechnology in hydrology

Water is a scarce resource with regard to growing contamination and population

requirements. One of the best uses of nanotechnology is to clean contaminated and polluted

water, thus saving millions of people from water borne diseases. Nanoparticles are used to 13

Fig: gold particles carrying anticancer drugs

coat filter papers and other water-cleaning agents to purify water to a greater degree by

killing more number of disease causing bacteria than conventional water purifiers. The

particles used in this process are nano silver particles. The process of water purification using

nanotechnology is extremely cost effective, which makes it even more wonderful.

Nanotechnology for environment protection

Accelerating amount of pollutants in the environment is not only destroying the health of

people but also causing extinction of hundreds of living organisms. Air pollution from

factories and industries is one of the major concerns all over the world. Nanotechnology is

used to filter out the impurities in the air being released through the chimneys of industries.

Refineries can reduce their level of pollution by implementation of this technology. What is

more, the filtered pollutants that will be left over can be used for other industrial and

construction purposes. This technology is also called green technology due to its environment

friendly implications.

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NANOTECHNOLOGY PRODUCTS:

Nanocomposites

Researchers at Pacific Northwest National Laboratory have developed a coating process to

make sponge-like silica latch onto toxic metals in water. Self-Assembled Monolayers on

Mesoporous Supports easily captures such metals as lead and mercury, which are then

recovered for reuse or contained in-place forever. © PNNL One example of a SAMMS

nanocomposite (Self-Assembled Monolayers on Mesoporous Supports).

A plastic nanocomposite is being used for "step assists" in the GM Safari and Astro Vans. It

is scratch-resistant, light-weight, and rust-proof, and generates improvements in strength and

reductions in weight, which lead to fuel savings and increased longevity. And in 2001,

Toyota started using nanocomposites in a bumper that makes it 60% lighter and twice as

resistant to denting and scratching. 

Fig: Electron micrograph of typical silicon nanocomposite cross section showing uniform distribution of

conductive carbon nanotube network. Photo courtesy of U.S. Air Force.

Nanocrystals

"Metal nanocrystals might be incorporated into car bumpers, making the parts stronger, or

into aluminum, making it more wear resistant. Metal nanocrystals might be used to produce

bearings that last longer than their conventional counterparts, new types of sensors and

components for computers and electronic hardware. 

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Nanocrystals of various metals have been shown to be 100 percent, 200 percent and even as

much as 300 percent harder than the same materials in bulk form. Because wear resistance

often is dictated by the hardness of a metal, parts made from nanocrystals might last

significantly longer than conventional parts."

Nanocrystals absorb then re-emit the light in a different color -- the size of the nanocrystal (in

the Angstrom scale) determines the color. 

Six different quantum dot solutions are shown, excited with a long-wave UV lamp. 

Quantum dots are molecular-scale optical beacons. Qdot™ nanocrystals behave like

molecular LEDs (light emitting diodes) by "lighting up" biological binding events with a

broad palette of applied colors. 

The nanocrystalline coating of silver rapidly kills a broad spectrum of bacteria in as little as

30 minutes. 

"Nanocrystals are an ideal light harvester in photovoltaic devices. (They) absorb sunlight

more strongly than dye molecules or bulk semiconductor material, therefore high optical

densities can be achieved while maintaining the requirement of thin films.

Nanoparticles

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Fig: Quantum dots

Fig: Nanocrystal

Stain-repellent Eddie Bauer Nano-CareTM khakis, with surface fibers of 10 to 100

nanometers, uses a process that coats each fiber of fabric with "nano-whiskers." Developed

by Nano-Tex, a Burlington Industries subsidiary. Dockers also makes khakis, a dress shirt

and even a tie treated with what they call "Stain Defender", another example of the same

nanoscale cloth treatment. 

 BASF's annual sales of aqueous polymer dispersion products amount to around $1.65 billion.

All of them contain polymer particles ranging from ten to several hundred nanometers in size.

Polymer dispersions are found in exterior paints, coatings and adhesives, or are used in the

finishing of paper, textiles and leather. Nanotechnology also has applications in the food

sector. Many vitamins and their precursors, such as carotinoids, are insoluble in water.

However, when skillfully produced and formulated as nanoparticles, these substances can

easily be mixed with cold water, and their bioavailability in the human body also increases.

Many lemonades and fruit juices contain these specially formulated additives, which often

also provide an attractive color. In the cosmetics sector, BASF has for several years been

among the leading suppliers of UV absorbers based on nanoparticulate zinc oxide.

Incorporated in sun creams, the small particles filter the high-energy radiation out of sunlight.

Because of their tiny size, they remain invisible to the naked eye and so the cream is

transparent on the skin.

Sunscreens are utilizing nanoparticles that are extremely effective at absorbing light,

especially in the ultra-violet (UV) range. Due to the particle size, they spread more easily,

cover better, and save money since you use less. And they are transparent, unlike traditional

screens which are white. These sunscreens are so successful that by 2001 they had captured

60% of the Australian sunscreen market. 

 Using aluminum nanoparticles, Argonide has created rocket propellants that burn at double

the rate. They also produce copper nanoparticles that are incorporated into automotive

lubricant to reduce engine wear. 

 AngstroMedica has produced a nanoparticulate-based synthetic bone. "Human bone is made

of a calcium and phosphate composite called Hydroxyapatite. By manipulation calcium and

phosphate at the molecular level, we have created a patented material that is identical in

structure and composition to natural bone. This novel synthetic bone can be used in areas

where natural bone is damaged or removed, such as in the in the treatment of fractures and 17

soft tissue injuries." 

Nanostructured Materials

 Nanodyne makes a tungsten-carbide-cobalt composite powder (grain size less than 15nm)

that is used to make a sintered alloy as hard as diamond, which is in turn used to make cutting

tools, drill bits, armor plate, and jet engine parts. 

 Kodak is producing OLED color screens (made of nanostructured polymer films) for use in

car stereos and cell phones. OLEDs (organic light emitting diodes) may enable thinner,

lighter, more flexible, less power consuming displays, and other consumer products such as

cameras, PDAs, laptops, televisions, and other as yet undreamt of applications. 

Nanoclays and Nanocomposites

 Used in packaging, like beer bottles, as a barrier, allowing for thinner material, with a

subsequently lighter weight, and greater shelf-life. 

$480B packaging and $300B plastics industries. Reduced weight means transportation costs

decline. Changing from glass and aluminum - think beer and soda bottles - to plastic reduces

production costs. Nanoclays help to hold the pressure and carbonation inside the bottle,

increasing shelf life. It is estimated that beer in these containers will gain an extra 60 days

(from 120 to 180) of shelf life, reducing spoilage, and decreasing overall costs to the end

user. Nanocor is one company producing nanoclays and nanocomposites, for a variety of

uses, including flame retardants, barrier film (as in juice containers), and bottle barrier (as

shown above). "They are not only used to improve existing products, but also are extending

their reach into areas formerly dominated by metal, glass and wood." See Nanocor 

Nanocomposite Coatings

Wilson Double Core tennis balls have a nanocomposite coating that keeps it bouncing twice

as long as an old-style ball. Made by InMat LLC, this nanocomposite is a mix of butyl

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rubber, intermingled with nanoclay particles, giving the ball substantially longer shelf life. 

Nanotubes

 Nanoledge makes carbon nanotubes for commercial uses, of which one mundane (marketing

tactic) use is in a tennis racket, made by Babolat. The yoke of the racket bends less during

ball impact, improving the player's performance. 

Once companies like Nanoledge can scale-up their production from grams, to pounds, to tons,

and can do so while controlling the type of nanotube they produce, the world becomes their

oyster: everywhere strength and weight are a factor - such as in the aerospace, automobile,

and airplane industries - they will make a major (disruptive) impact.

Applied Nanotech recently demonstrated a 14" monochrome display based on electron

emission from carbon nanotubes. 

Nanocatalysts

China's largest coal company (Shenhua Group) has licensed technology from Hydrocarbon

Technologies that will enable it to liquify coal and turn it into gas. The process uses a gel-

based nanoscale catalyst, which improves the efficiency and reduces the cost. 

 One of the characteristic properties of all nanoparticles has been used from the outset in the

manufacture of automotive catalytic converters: The surface area of the particles increases

dramatically as the particle size decreases and the weight remains the same. A variety of

chemical reactions take place on the surface of the catalyst, and the larger the surface area,

the more active the catalyst. Nanoscale catalysts thus open the way for numerous process

innovations to make many chemical processes more efficient and resource-saving – in other

words more competitive.

Nanofilters

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Argonide Nanomaterials, an Orlando based manufacturer of nanoparticles and nanofiltration

products, makes a filter that is capable of filtering the smallest of particles. The performance

is due to it’s nano size alumina fiber, which attracts and retains sub-micron and nanosize

particles. This disposable filter retains 99.9999+% of viruses at water flow rates several

hundred times greater than virus-rated ultra porous membranes. It is useful for sterilization of

biological, pharmaceutical and medical serums, protein separation, collector/concentrator for

biological warfare detectors, and several other applications. 

NANOTECHNOLOGY FUTURE:

Today nanotechnology is still in a formative phase--not unlike the condition of computer

science in the 1960s or biotechnology in the 1980s. Yet it is maturing rapidly. Between 1997

and 2005, investment in nanotech research and development by governments around the

world soared from $432 million to about $4.1 billion, and corresponding industry investment

exceeded that of governments by 2005. By 2015, products incorporating nanotech will

contribute approximately $1 trillion to the global economy. About two million workers will

be employed in nanotech industries, and three times that many will have supporting jobs.

Descriptions of nanotech typically characterize it purely in terms of the minute size of the

physical features with which it is concerned--assemblies between the size of an atom and

about 100 molecular diameters. That depiction makes it sound as though nanotech is merely

looking to use infinitely smaller parts than conventional engineering. But at this scale,

rearranging the atoms and molecules leads to new properties. One sees a transition between

the fixed behavior of individual atoms and molecules and the adjustable behavior of

collectives. Thus, nanotechnology might better be viewed as the application of quantum

theory and other nano-specific phenomena to fundamentally control the properties and

behavior of matter.

Over the next couple of decades, nanotech will evolve through four overlapping stages of

industrial prototyping and early commercialization. The first one, which began after 2000,

involves the development of passive nanostructures: materials with steady structures and

functions, often used as parts of a product. These can be as modest as the particles of zinc

oxide in sunscreens, but they can also be reinforcing fibers in new composites or carbon

nanotube wires in ultraminiaturized electronics.20

Rearranging atoms leads to new properties.

The second stage, which began in 2005, focuses on active nanostructures that change their

size, shape, conductivity or other properties during use. New drug-delivery particles could

release therapeutic molecules in the body only after they reached their targeted diseased

tissues. Electronic components such as transistors and amplifiers with adaptive functions

could be reduced to single, complex molecules.

Starting around 2010, workers will cultivate expertise with systems of nanostructures,

directing large numbers of intricate components to specified ends. One application could

involve the guided self-assembly of nanoelectronic components into three-dimensional

circuits and whole devices. Medicine could employ such systems to improve the tissue

compatibility of implants, or to create scaffolds for tissue regeneration, or perhaps even to

build artificial organs.

After 2015-2020, the field will expand to include molecular nanosystems--heterogeneous

networks in which molecules and supramolecular structures serve as distinct devices. The

proteins inside cells work together this way, but whereas biological systems are water-based

and markedly temperature-sensitive, these molecular nanosystems will be able to operate in a

far wider range of environments and should be much faster. Computers and robots could be

reduced to extraordinarily small sizes. Medical applications might be as ambitious as new

types of genetic therapies and antiaging treatments. New interfaces linking people directly to

electronics could change telecommunications.

Over time, therefore, nanotechnology should benefit every industrial sector and health care

field. It should also help the environment through more efficient use of resources and better

methods of pollution control. Nanotech does, however, pose new challenges to risk

governance as well. Internationally, more needs to be done to collect the scientific

information needed to resolve the ambiguities and to install the proper regulatory oversight.

Helping the public to perceive nanotech soberly in a big picture that retains human values and

quality of life will also be essential for this powerful new discipline to live up to its

astonishing potential.

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FUTURE PRODUCTS:

In the world of "Star Trek," machines called replicators can produce practically any

physical object, from weapons to a steaming cup of Earl Grey tea. Long considered to be

exclusively the product of science fiction, today some people believe replicators are a very

real possibility. They call it molecular manufacturing, and if it ever does become a reality,

it could drastically change the world.

Fig: Replicator

Atoms and molecules stick together because they have complementary shapes that lock

together, or charges that attract. Just like with magnets, a positively charged atom will stick to

a negatively charged atom. As millions of these atoms are pieced together by nanomachines,

a specific product will begin to take shape. The goal of molecular manufacturing is to

manipulate atoms individually and place them in a pattern to produce a desired structure.

The first step would be to develop nanoscopic machines, called assemblers, that scientists

can program to manipulate atoms and molecules at will. Rice University Professor Richard

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Smalley points out that it would take a single nanoscopic machine millions of years to

assemble a meaningful amount of material. In order for molecular manufacturing to be

practical, you would need trillions of assemblers working together simultaneously. Eric

Drexler believes that assemblers could first replicate themselves, building other assemblers.

Each generation would build another, resulting in exponential growth until there are enough

assemblers to produce objects

Fig: Assembler

Assemblers might have moving parts like the nanogears in this concept drawing.

Trillions of assemblers and replicators could fill an area smaller than a cubic millimeter, and

could still be too small for us to see with the naked eye. Assemblers and replicators could

work together to automatically construct products, and could eventually replace all traditional

labor methods. This could vastly decrease manufacturing costs, thereby making consumer

goods plentiful, cheaper and stronger. Eventually, we could be able to replicate anything,

including diamonds, water and food. Famine could be eradicated by machines that fabricate

foods to feed the hungry.

Nanotechnology may have its biggest impact on the medical industry. Patients will drink

fluids containingnanorobots programmed to attack and reconstruct the molecular structure

of cancer cells and viruses. There's even speculation that nanorobots could slow or reverse

the aging process, and life expectancy could increase significantly. Nanorobots could also be

programmed to perform delicate surgeries -- suchnanosurgeons could work at a level a

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thousand times more precise than the sharpest scalpel [source:International Journal of

Surgery]. By working on such a small scale, a nanorobot could operate without leaving the

scars that conventional surgery does. Additionally, nanorobots could change your physical

appearance. They could be programmed to perform cosmetic surgery, rearranging your atoms

to change your ears, nose, eye color or any other physical feature you wish to alter.

What is MEMS Technology?

Micro-Electro-Mechanical Systems, or MEMS, is a technology that in its most general form

can be defined as miniaturized mechanical and electro-mechanical elements (i.e., devices and

structures) that are made using the techniques of microfabrication. The critical physical

dimensions of MEMS devices can vary from well below one micron on the lower end of the

dimensional spectrum, all the way to several millimeters. Likewise, the types of MEMS

devices can vary from relatively simple structures having no moving elements, to extremely

complex electromechanical systems with multiple moving elements under the control of

integrated microelectronics. The one main criterion of MEMS is that there are at least some

elements having some sort of mechanical functionality whether or not these elements can

move. The term used to define MEMS varies in different parts of the world. In the United

States they are predominantly called MEMS, while in some other parts of the world they are

called “Microsystems Technology” or “micromachined devices”.

While the functional elements of MEMS are miniaturized structures, sensors, actuators, and

microelectronics, the most notable (and perhaps most interesting) elements are the

microsensors and microactuators. Microsensors and microactuators are appropriately

categorized as “transducers”, which are defined as devices that convert energy from one form

to another. In the case of microsensors, the device typically converts a measured mechanical

signal into an electrical signal.

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Over the past several decades MEMS researchers and developers have demonstrated an

extremely large number of microsensors for almost every possible sensing modality including

temperature, pressure, inertial forces, chemical species, magnetic fields, radiation, etc.

Remarkably, many of these micromachined sensors have demonstrated performances

exceeding those of their macroscale counterparts. That is, the micromachined version of, for

example, a pressure transducer, usually outperforms a pressure sensor made using the most

precise macroscale level machining techniques. Not only is the performance of MEMS

devices exceptional, but their method of production leverages the same batch fabrication

techniques used in the integrated circuit industry – which can translate into low per-device

production costs, as well as many other benefits. Consequently, it is possible to not only

achieve stellar device performance, but to do so at a relatively low cost level. Not

surprisingly, silicon based discrete microsensors were quickly commercially exploited and

the markets for these devices continue to grow at a rapid rate.

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Fig: A surface micromachined electro-statically-actuated micromotor fabricated by the MNX. This device

is an example of a MEMS-based microactuator.

The real potential of MEMS starts to become fulfilled when these miniaturized sensors,

actuators, and structures can all be merged onto a common silicon substrate along with

integrated circuits (i.e., microelectronics). While the electronics are fabricated using

integrated circuit (IC) process sequences (e.g., CMOS, Bipolar, or BICMOS processes), the

micromechanical components are fabricated using compatible "micromachining" processes

that selectively etch away parts of the silicon wafer or add new structural layers to form the

mechanical and electromechanical devices. It is even more interesting if MEMS can be

merged not only with microelectronics, but with other technologies such as photonics,

nanotechnology, etc. This is sometimes called “heterogeneous integration.” Clearly, these

technologies are filled with numerous commercial market opportunities.

While more complex levels of integration are the future trend of MEMS technology, the

present state-of-the-art is more modest and usually involves a single discrete microsensor, a

single discrete microactuator, a single microsensor integrated with electronics, a multiplicity

of essentially identical microsensors integrated with electronics, a single microactuator

integrated with electronics, or a multiplicity of essentially identical microactuators integrated

with electronics. Nevertheless, as MEMS fabrication methods advance, the promise is an

enormous design freedom wherein any type of microsensor and any type of microactuator

can be merged with microelectronics as well as photonics, nanotechnology, etc., onto a single

substrate.

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Fig: A surface micromachined resonator fabricated by the MNX. This device can be used as both a

microsensor as well as a microactuator.

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HAZARDS OF NANOTECHNOLOGY:-

Hazards to Humans:

In terms of liability cover, the insurance industry needs to know which nanoparticles are

hazardous to humans, and what levels of concentration are required to cause harm. Can

nanoparticles cause chronic health effects similar to asbestosis? The short answer is that we

simply do not know.

Initial investigations carried out show some nanoparticles are acutely toxic when compared to

larger particles composed of the same material, such as ultra-fine carbon and diesel exhaust

particles respectively. Certain organs in mice have been shown to be adversely affected by

some nanoparticles as well as significantly reduced offspring production in some aquatic life.

If these effects are caused in other animals they may be possible in humans, though there

have been no human studies to confirm this. Studies looking at the chronic effects of

nanoparticles are much less common, though some are underway. The UK Council for

Science and Technology highlighted that there is insufficient research into the toxicology,

health and environmental effects of nanomaterials. This call has been taken seriously and

there are now efforts to increase the amount of research into nanotoxicology.

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Fig: Types of hazards to humans

There are several ways that nanoparticles can enter the body. These include inhalation,

ingestion, absorption through the skin and direct injection for medicinal purposes. Once the

particles are in the body they may be transported throughout the body before they are ejected,

if at all.

Inhalation of nanoparticles

Particles breathed into the lungs can cause damage and scarring, which over long periods of

exposure can lead to long term breathing difficulties.

This is an analogous process by which asbestos fibres cause asbestosis. The fibres lodge deep

within the lungs and trigger the local immune system, which sends specialised immune cells

that try to digest the fibres and repair any damage by depositing new tissue. As the fibres are

highly resistant, the immune cells cannot digest them, die off, cause more immune cells to

attack the foreign body, and yet more tissue to be deposited. In some cases this can also cause

the cells to become cancerous. Over many years of exposure this leads to thickening of the

lung walls and reduces the amount of oxygen that can be absorbed from the air and decreases

the amount of carbon dioxide that can be breathed out. This causes a shortness of breath and

hence a reduced ability to perform any activities that require exertion and costly oxygen

therapy may be required.

Carbon nanotubes are potentially toxic to humans. Carbon nanotubes can be very similar to

asbestos fibres; they are strong and can have a similar shape to asbestos fibres. There has

been much research into the potential applications of nanotubes; however research into their

toxicity is currently fragmented. Some studies refute any negative effects of carbon

nanotubes, but several of the reviews conclude with statements similar to the following:

“…carbon nanotubes are potentially toxic to humans and that strict industrial hygiene

measures should to be taken to limit exposure during their manipulation”. Julie Muller et al.

This statement was from a study that found carbon nanotubes cause inflammation in the lungs

and scarring. This is a similar effect to asbestos exposure and gives clear indication that the

potential risk from carbon nanotubes should be taken seriously.

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Titanium dioxide and carbon nanoparticles also show detrimental effects when inhaled.

Carbon nanoparticles in this sense refer to a small cluster of carbon atoms and not in the form

of tubes. Mice suffered inflamed lungs when exposed to these particles. One study by Tobias

Stoeger et al showed that if the total surface area of all the particles of each dose was

progressively reduced, by using larger particles, a surface area threshold was found. Beyond

this threshold, in effect if the particles became too large, no short term adverse effects were

observed. While this is only one study it may indicate a safe level for short-term exposure to

nanoparticles.

Cerium oxide nanoparticles are added to some diesel fuels to reduce nitrogen oxide emissions

and increase engine efficiency. Nitrogen oxide has been linked to acid rain and smog, and a

reduction of this pollutant is an important goal for car manufacturers. Use of cerium oxide

will release it into the atmosphere through car exhaust; and there are concerns that it may

damage the lungs if inhaled and one study appears to lend weight to this theory. This is

another nanotechnology where a debate is required to determine if the gain offered by the

new technology outweighs the potential risks.

Absorption through skin

Nanoparticles are being used in a number of products which are placed in direct contact with

skin, including clothing, cosmetics and sun cream.

Once absorbed through the skin if the nanoparticles come into contact with blood vessels they

may behave in a similar way as if they had been ingested, namely collecting within certain

organs or cells within the body.

This again is another call to determine the toxicity of widely used nanoparticles.

Hazards to Environment:

Removing nanoparticles from the environment may also present a significant problem due to

their small size. Particles could conceivably be absorbed quickly into plants and soil or

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transported large distances in the air or suspended in water; and how do you filter out of the

environment particles only a few atoms wide?

Hazards to aquatic life:

Fish are susceptible to copper nanoparticles, which induce gill injury and acute lethality

according to current research conducted with concentrations of 1.5 mg/litre. A fraction of the

particles will dissolve to produce soluble copper, which is known to be toxic, but the toxic

effects seen could not be explained solely by exposure to soluble copper. This implies the

additional effects were cause because the copper was present on the nanoscale. Titanium

dioxide nanoparticles have also been investigated but preliminary studies show that, while the

particles do cause respiratory stress, it was not considered a major toxicant at the

concentrations of one mg/litre. The carbon fullerene, C60, has also been shown to

significantly reduce offspring production for freshwater shrimp which would have negative

implications for populations of species further up the food chain.

31Fig: Hazards to aquatic life

Fig: Hazards to Environment

CONCLUSION

Nanotechnology is a growing field today. It has made true many possibilities of human life

style. Many product from nanotechnology are very beneficial . In the near future this

technology will come with new advancements in technical field. MEMS devices are

revolutionary outcome of this field.

But we have move forward with a thinking of sustainable development i.e. growing without

harming the environment. Only then it will be proved as good technology.

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BIBLIOGRAPHY

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