8th Sem Seminar Report

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SEMINAR REPORT ON NANOTECHNOLOGY-The next really big small thing BY ARCHANA ELECTRICAL & ELECTRONICS ENGG. 8 th SEM EE/07/11 Submitted To:- Mhod. ILYAS LECTURER (ELECTRICAL & ELECTRONICS ENGG.)

Transcript of 8th Sem Seminar Report

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SEMINAR REPORTON

NANOTECHNOLOGY-The next really big small thing

BY

ARCHANA

ELECTRICAL & ELECTRONICS ENGG.

8th SEM

EE/07/11

Submitted To:-

Mhod. ILYAS

LECTURER (ELECTRICAL & ELECTRONICS ENGG.)

AL-FALAH SCHOOL OF ENGG. AND TECHNOLOGY, DHAUJ FARIDABAD, HARYANA, MDU(ROHTAK)

2011

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Acknowledgement

Materials in this term paper have been drawn from a wide variety of sources

including weekly journals, books, magazines and Internet. Sources of these works

are cited where they are discussed in the text, and I hope that I have made no

omissions.

I am deeply indebted to Mhod ILYAS, my mentor without whose support and

encouragement, this project couldn’t have been accomplished.

Finally I would like to thank my family & friends. I sincerely extend my deep felt

regards for their able guidance throughout this training period and Al-falah School

of Engg and Tech.,Dhauj,Faridabad for providing eminent environment and

essential resources to complete my term paper.

ARCHANA

EEE,8th Sem

EE/07/11

AFSET, Dhauj, Faridabad

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Table of contents

1) Acknowledgement

2) Introduction

3) Origins

4) Fundamental Concepts

5) Misconceptations

6) Advantages and Disavantages

7) Current Resarch

8) Tools and Techniques

9) Applications

10) Conclusion

11) Health and Environmental Concern

12) Regulation

13) References

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Nanotechnology

Imagine a supercomputer no bigger than a human cell. Imagine a four-person, surface-to-orbit spacecraft no larger or more expensive than the family car. Imagine attaining immortality by drinking a medicine. These are just a few products expected from Nanotechnology.

Nanotechnology is molecular manufacturing or, more simply, building things one atom or molecule at a time with programmed nanoscopic robot arms; Nanotechnology proposes the construction of novel molecular devices possessing extraordinary properties. The trick is to manipulate atoms Individually and place them exactly where needed to produce the desired Structur.

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 and their potential effects on global economics, as well as speculation about variousdoomsday scenarios. These concerns have led to a debate among advocacy groups and governments on whether special regulation of nanotechnology is warranted.

The goal of early nanotechnology is to produce the first nano-sized robot Arm capable of manipulating atoms and molecules into a useful product or Copies of itself. Nanotechnology will arrive with the development of the first "Universal Assembler" that has the ability to build with single atoms anything one's software defines.  This paper deals with the various possible applications of nanotechnology and the process involved.

What is nanotechnology all about?

Nanotechnology is the engineering of tiny machines — the projected ability to build things from the bottom upinside personal nanofactories (PNs), using techniques and tools being developed today to make complete, highly advanced products. Ultimately, nanotechnology will enable

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control of matter at the nanometer scale, using mechanochemistry. Shortly after this envisioned molecular machinery is created, it will result in amanufacturing revolution, probably causing severe disruption. It also has serious economic, social, environmental, and military implications.

Many words have been written about the dangers of advanced nanotechnology. Most of the threatening scenarios involve tiny manufacturing systems that run amok, or are used to create destructive products. A manufacturing infrastructure built around a centrally controlled, relatively large, self-contained manufacturing system would avoid these problems. A controlled nanofactory would pose no inherent danger, and it could be deployed and used widely. Cheap, clean, convenient, on-site manufacturing would be possible without the risks associated with uncontrolled nanotech fabrication or excessive regulation. Control of the products could be administered by a central authority; intellectual property rights could be respected.

What's a personal nanofactory?

It's a proposed new appliance, something that might sit on a countertop in your home. To build a personal nanofactory (PN), you need to start with a working fabricator, a nanoscale device that can combine individual molecules into useful shapes. A fabricator could build a very small nanofactory, which then could build another one twice as big, and so on. Within a period of weeks, you have a tabletop model.

Products made by a PN will be assembled from nanoblocks, which will be fabricated within the nanofactory. Computer aided design (CAD) programs will make it possible to create state-of-the-art products simply by specifying a pattern of predesigned nanoblocks. The question of when we will see a flood of nano-built products boils down to the question of how quickly the first fabricator can be designed and built.

How does 'mechanochemistry' work?

It's a bit like enzymes (if you know your chemistry): you fix onto a molecule or two, then twist or pull or push in a precise way until a chemical reaction happens right where you want it. This happens in a vacuum, so you don't have water molecules bumping around. It's a lot more controllable that way.

So, if you want to add an atom to a surface, you start with that atom bound to a molecule called a "tool tip" at the end of a mechanical manipulator. You move the atom to the point where you want it to end up. You move the atom next to the surface, and make sure that it has a weaker bond to the tool tip than to the surface. When you bring them close enough, the bond will transfer. This is ordinary chemistry: an atom moving from one molecule to another when they come close enough to each other, and when the movement is energetically favorable. What's

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different about mechanochemistry is that the tool tip molecule can be positioned by direct computer control, so you can do this one reaction at a wide variety of sites on the surface. Just a few reactions give you a lot of flexibility in what you make.

MECHANOSYNTHETIC REACTIONS Based on quantum chemistry by Walch and Merkle [Nanotechnology, 9, 285 (1998)], to deposit carbon, a device moves a vinylidenecarbene along a barrier-free path to bond to a diamond (100) surface dimer, twists 90° to break a pi bond, and then pulls to cleave the remaining sigma bond.

Origins

Buckminsterfullerene C60, also known as the buckyball, is a representative member of thecarbon structures known asfullerenes. Members of the fullerene family are a major subject of research falling under the nanotechnology umbrella.

The first use of the concepts found in 'nano-technology' (but pre-dating use of that name) was in "There's Plenty of Room at the Bottom", a talk given by physicist Richard Feynman at an American Physical Society meeting at California Institute of Technology (Caltech) on

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December 29, 1959. Feynman described a process by which the ability to manipulate individual atoms and molecules might be developed, using one set of precise tools to build and operate another proportionally smaller set, and so on down to the needed scale. In the course of this, he noted, scaling issues would arise from the changing magnitude of various physical phenomena: gravity would become less important, surface tension and van der Waals attraction would become increasingly more significant, etc. This basic idea appeared plausible, and exponential assembly enhances it with parallelism to produce a useful quantity of end products. The term "nanotechnology" was defined by Tokyo University of Science Professor Norio Taniguchi in a 1974 pape as follows: "'Nano-technology' mainly consists of the processing of, separation, consolidation, and deformation of materials by one atom or by one molecule." In the 1980s the basic idea of this definition was explored in much more depth by Dr. K. Eric Drexler, who promoted the technological significance of nano-scale phenomena and devices through speeches and the books Engines of Creation: The Coming Era of Nanotechnology (1986) and Nanosystems: Molecular Machinery, Manufacturing, and Computation and so the term acquired its current sense. Engines of Creation is considered the first book on the topic of nanotechnology. Nanotechnology and nanoscience got started in the early 1980s with two major developments; the birth of cluster science and the invention of the scanning tunneling microscope (STM). This development led to the discovery of fullerenes in 1985 and carbon nanotubes a few years later. In another development, the synthesis and properties of semiconductor nanocrystals was studied; this led to a fast increasing number of metal and metal oxide nanoparticles and quantum dots. The atomic force microscope (AFM or SFM) was invented six years after the STM was invented. In 2000, the United States National Nanotechnology Initiative was founded to coordinate Federal nanotechnology research and development and is evaluated by the President's Council of Advisors on Science and Technology.

Fundamental concepts

Nanotechnology is the engineering of functional systems at the molecular scale. This covers both current work and concepts that are more advanced. In its original sense, nanotechnology refers to the projected ability to construct items from the bottom up, using techniques and tools being developed today to make complete, high performance products.

One nanometer (nm) is one billionth, or 10−9, of a meter. By comparison, typical carbon-carbon bond lengths, or the spacing between these atoms in a molecule, are in the range 0.12–0.15 nm, and a DNA double-helix has a diameter around 2 nm. On the other hand, the smallestcellular life-forms, the bacteria of the genus Mycoplasma, are around 200 nm in length. By convention, nanotechnology is taken as the scale range 1 to 100 nm following the definition used by the National Nanotechnology Initiative in the US. The lower limit is set by the size of atoms (hydrogen has the smallest atoms, which are approximately a quarter of a nm diameter) since nanotechnology must build its devices from atoms and molecules. The upper limit is more

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or less arbitrary but is around the size that phenomena not observed in larger structures start to become apparent and can be made use of in the nano device.These new phenomena make nanotechnology distinct from devices which are merely miniaturised versions of an equivalent macroscopic device; such devices are on a larger scale and come under the description ofmicrotechnology.

Areas of physics such as nanoelectronics, nanomechanics, nanophotonics and nanoionics have evolved during the last few decades to provide a basic scientific foundation of nanotechnology.

A number of physical phenomena become pronounced as the size of the system decreases. These include statistical mechanical effects, as well as quantum mechanical effects, for example the “quantum size effect” where the electronic properties of solids are altered with great reductions in particle size. This effect does not come into play by going from macro to micro dimensions. However, quantum effects become dominant when the nanometer size range is reached, typically at distances of 100 nanometers or less, the so called quantum realm. Diffusion and reactions at nanoscale, nanostructures materials and nanodevices with fast ion transport are generally referred to nanoionics. 

Materials reduced to the nanoscale can show different properties compared to what they exhibit on a macroscale, enabling unique applications. For instance, opaque substances become transparent (copper); stable materials turn combustible (aluminum); insoluble materials become soluble (gold). A material such as gold, which is chemically inert at normal scales, can serve as a potent chemical catalyst at nanoscales. Much of the fascination with nanotechnology stems from these quantum and surface phenomena that matter exhibits at the nanoscale.

The coming technological revolutionIt seems like magic. A small appliance, about the size of a washing machine, that is able to manufacture almost anything. It is called ananofactory. Fed with simple chemical stocks, this amazing machine breaks down molecules, and then reassembles them into any product you ask for. Packed with nanotechnology and robotics, weighing 200 pounds and standing half as tall as a person, it can produce two tons per day of products. Control is simple: a touch screen selects the type and number of products to produce. It costs very little to operate, just the price of materials fed into it. In one hour, $20 worth of chemicals can be converted into 100 pairs of shoes, or 50 shovels, or 200 cell phones, or even a duplicate nanofactory.

Impossible? Today, maybe, but not tomorrow. The technology to create such a machine is speedily being developed. A nanofactory will be the end result of a convergence between nanotechnology (molecular scale engineering), rapid prototyping, and automated assembly. These are all present-day technologies. None of them has yet reached its full potential, but each of them is advancing rapidly, driven by powerful economic, social, and military forces..

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Some experts claim that a crash program started today could complete the first working nanofactory within a decade at a cost of between five and ten billion dollars. And once the first one is built, it can start making copies of itself. But imagine the economic, environmental and humanitarian benefits, when nearly any product can be manufactured on the spot for about $1 per pound. No more shipping costs or time spent waiting. No more wasted resources or hazardous byproducts. No more starvation, homelessness, or poverty.

It sounds too good to be true: a non-polluting, personal-size machine that within a few hours and for a few dollars can manufacture almost anything—clothing, books, tools, communication devices—but there is a catch. It can also manufacture weapons, poisons, tiny surveillance cameras, and other illicit products. How will this be controlled?

Why do some scientists dismiss this stuff as science fiction?

The whole concept of advanced nanotechnology — molecular manufacturing (MM) — is so complex and unfamiliar, and so staggering in its implications, that a few scientists, engineers, and other pundits have flatly declared it to be impossible. The debate is further confused by science-fictional hype and media misconceptions.

It should be noted that none of those who dismiss MM are experts in the field. They may work in chemistry, biotechnology, or other nanoscale sciences or technologies, but are not sufficiently familiar with MM theory to critique it meaningfully.

Many of the objections, including those of the late Richard Smalley, do not address the actual published proposals for MM. The rest are unfounded and incorrect assertions, contradicted by detailed calculations based on the relevant physical laws.

What we're doing about it

The mission of the Center for Responsible Nanotechnology (a non-profit program of World Care) is to raise awareness of the issues presented by molecular nanotechnology: the benefits and dangers, and the possibilities for responsible use. 

Designing and developing molecular nanotechnology (MNT) is a major challenge in itself. It will not be easy, and it will not happen overnight. But it will happen, and it should happen. A greater challenge—and one that has not been addressed—is creating the infrastructure to administer the most powerful technology imaginable in a way that allows its safe and effective use, but that protects investors, users, and innocent bystanders.

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"Nanotechnology will give rise to a host of novel social, ethical, philosophical and legal issues. It will be important to have a group in place to predict and work to alleviate anticipated problems."— US Rep. Mike Honda (D-Cal.)

The technology is already on its way. But who will control it? If MNT is not administered properly, there is great risk of it being used badly—either by the entity that first develops it, or by groups that later gain access to it. Development or control of the technology by a special interest group would probably lead to military or economic oppression. Two competing programs could lead to an unstable arms race. Uncontrolled release would make the full power of the technology available to terrorists, criminals, dictators, and irresponsible users. The safest course appears to be a single, rapid, worldwide development program by an organization that recognizes the necessity of wise administration.

Christine Peterson of the Foresight Nanotech Institute made this point in her April 2003 testimony to the US House Committee on Science:

"In developing a powerful technology, delay may seem to add safety, but the opposite could be the case for molecular manufacturing. A targeted R&D project today aimed at this goal would need to be large and, therefore, visible and relatively easy to monitor. As time passes, the nanoscale infrastructure improves worldwide, enabling faster development everywhere, including places that are hard to monitor. The safest course may be to create a fast-moving, well-funded, highly-focused project located where it can be closely watched by all interested parties. Estimates are that such a project could reach its goal in 10-15 years."

Effective administration will not be easy, and it is unlikely that a wise course of action can evolve without guidance. There are too many risks to avoid, too many benefits to preserve, and too many special interests to satisfy. A technology this powerful has implications in the areas of national security, commercial rights, human rights, global environment, and even cultural stability. Any single organization with a narrow focus will create too many regulations while trying to control things that it does not know how to control; too many regulations will create an unregulated black market, which creates unacceptable risks.

The purpose of CRN is to investigate the wise use of molecular nanotechnology, and to educate those who will influence its use, or be affected by it. Through this we hope to see our vision made real: a world in which MNT is widely used for productive and beneficial purposes, and where malicious uses are limited by effective administration of the technology. 

Is nanotechnology bad or good?

Nanotechnology offers great potential for benefit to humankind, and also brings severe dangers. While it is appropriate to examine carefully the risks and possible toxicity of nanoparticles and

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other products of nanoscale technology, the greatest hazards are posed by malicious or unwise use of molecular manufacturing. CRN's focus is on designing and promoting mechanisms for safe development and effective administration of MM.

Advanced Nanotechnology and Its Risks

As early as 1959, Richard Feynman proposed building devices with each atom precisely placed. In 1986, Eric Drexler published an influential book, Engines of Creation, in which he described some of the benefits and risks of such a capability. If molecules and devices can be manufactured by joining individual atoms under computer control, it will be possible to build structures out of diamond, 100 times as strong as steel; to build computers smaller than a bacterium; and to build assemblers and mini-factories of various sizes, capable of making complex products and even of duplicating themselves.

Drexler's subsequent book, Nanosystems, substantiated these remarkable claims, and added still more. A self-contained tabletop factory could produce its duplicate in one hour. Devices with moving parts could be incredibly efficient. Molecular manufacturing operations could be carried out with failure rates less than one in a quadrillion. A computer would require a miniscule fraction of a watt and one trillion of them could fit into a cubic centimeter.

Clearly, the unrestricted availability of advanced nanotechnology poses grave risks, which may well outweigh the benefits of clean, cheap, convenient, self-contained manufacturing. As analyzed in Forward to the Future: Nanotechnology and Regulatory Policy, some restriction is likely to be necessary. However, as was also pointed out in that study, an excess of restriction will enable the same problems by increasing the incentive for covert development of advanced nanotechnology. That paper considered regulation on a one-dimensional spectrum, from full relinquishment to complete lack of restriction. As will be shown below, a two-dimensional understanding of the problem—taking into account both control of nanotech manufacturing capability and control of its products—allows targeted restrictions to be applied, minimizing the most serious risks while preserving the potential benefits.

If MM is so dangerous, why not just completely ban all research and development?

Viewed with pessimism, molecular manufacturing could appear far too risky to be allowed to develop to anywhere near its full potential. However, a naive approach to limiting R&D, such as relinquishment, is flawed for at least two reasons. First, it will almost certainly be impossible to prevent the development of MM somewhere in the world. China, Japan, and other Asian nations have thriving nanotechnology programs, and the rapid advance of enabling technologies such as biotechnology, MEMS, and scanning-probe microscopy ensures that R&D efforts will be

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far easier in the near future than they are today. Second, MM will provide benefits that are simply too good to pass up, including environmental repair; clean, cheap, and efficient manufacturing; medical breakthroughs; immensely powerful computers; and easier access to space

Current research

Nanomaterials

The nanomaterials field includes subfields which develop or study materials having unique properties arising from their nanoscale dimensions.

Graphical representation of a rotaxane, useful as a molecular switch

Interface and colloid science  has given rise to many materials which may be useful in nanotechnology, such as carbon nanotubes and other fullerenes, and various nanoparticles andnanorods. Nanomaterials with fast ion transport are related also to nanoionics andnanoelectronics.

Nanoscale materials  can also be used for bulk applications; most present commercial applications of nanotechnology are of this flavor.

Progress has been made in using these materials for medical applications; see Nanomedicine.

Bottom-up approachesThese seek to arrange smaller components into more complex assemblies.

DNA nanotechnology  utilizes the specificity of Watson–Crick basepairing to construct well-defined structures out of DNA and other nucleic acids.

Approaches from the field of "classical" chemical synthesis also aim at designing molecules with well-defined shape (e.g. bis-peptides

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Atomic force microscope  tips can be used as a nanoscale "write head" to deposit a chemical upon a surface in a desired pattern in a process called dip pen nanolithography. This technique fits into the larger subfield of nanolithography.

Top-down approachesThese seek to create smaller devices by using larger ones to direct their assembly.

Many technologies that descended from conventional solid-state silicon methods for fabricatingmicroprocessors are now capable of creating features smaller than 100 nm, falling under the definition of nanotechnology. 

Solid-state techniques can also be used to create devices known as nanoelectromechanical system s  or NEMS, which are related to microelectromechanical system s  or MEMS.

Focused ion beams  can directly remove material, or even deposit material when suitable pre-cursor gasses are applied at the same time.

Atomic force microscope  tips can be used as a nanoscale "write head" to deposit a resist, which is then followed by a etching process to remove material in a top-down method.

Functional approachesThese seek to develop components of a desired functionality without regard to how they might be assembled.

Molecular electronics  seeks to develop molecules with useful electronic properties. These could then be used as single-molecule components in a nanoelectronic device.For an example see rotaxane.

Synthetic chemical methods can also be used to create synthetic molecular motors, such as in a so-called nanocar.

Biomimetic approaches

Bionics  or biomimicry seeks to apply biological methods and systems found in nature, to the study and design of engineering systems and modern technology. Biomineralization is one example of the systems studied.

Bionanotechnology  the use of biomolecules for applications in nanotechnology, including use of viruses.

SpeculativeThese subfields seek to anticipate what inventions nanotechnology might yield, or attempt to propose an agenda along which inquiry might progress. These often take a big-picture view of nanotechnology, with more emphasis on its societal implications than the details of how such inventions could actually be created.

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Molecular nanotechnology  is a proposed approach which involves manipulating single molecules in finely controlled, deterministic ways. This is more theoretical than the other subfields and is beyond current capabilities.

Nanorobotics  centers on self-sufficient machines of some functionality operating at the nanoscale. There are hopes for applying nanorobots in medicine

Productive nanosystems  are "systems of nanosystems" which will be complex nanosystems that produce atomically precise parts for other nanosystems, not necessarily using novel nanoscale-emergent properties, but well-understood fundamentals of manufacturing. Because of the discrete (i.e. atomic) nature of matter and the possibility of exponential growth, this stage is seen as the basis of another industrial revolution. 

Programmable matter  seeks to design materials whose properties can be easily, reversibly and externally controlled though a fusion ofinformation science and materials science.

Due to the popularity and media exposure of the term nanotechnology, the words picotechnology and femtotechnology have been coined in analogy to it, although these are only used rarely and informally.

Tools and techniques

Typical AFM setup. A microfabricated cantilever with a sharp tip is deflected by features on a sample surface, much like in a phonograph but on a much smaller scale. Alaser beam reflects off the backside of the cantilever into a set of photodetectors, allowing the deflection to be measured and assembled into an image of the surface.

There are several important modern developments. The atomic force microscope(AFM) and the Scanning Tunneling Microscope (STM) are two early versions of scanning probes that launched nanotechnology. There are other types of scanning probe microscopy, all flowing from the ideas of the scanning confocal microscopedeveloped by Marvin Minsky in 1961 and the scanning acoustic microscope (SAM) developed by Calvin Quate and coworkers in the

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1970s, that made it possible to see structures at the nanoscale.Feature-oriented scanning-positioning methodology suggested by Rostislav Lapshin appears to be a promising way to implement these nanomanipulations in automatic mode.However, this is still a slow process because of low scanning velocity of the microscope. Various techniques of nanolithography such as optical lithography, X-ray lithography dip pen nanolithography, electron beam lithography or nanoimprint lithography were also developed. Lithography is a top-down fabrication technique where a bulk material is reduced in size to nanoscale pattern.

 Atomic force microscopesand scanning tunneling microscopes can be used to look at surfaces and to move atoms around. By designing different tips for these microscopes, they can be used for carving out structures on surfaces and to help guide self-assembling structures. By using, for example,feature-oriented scanning-positioning approach, atoms can be moved around on a surface with scanning probe microscopy techniques.At present, it is expensive and time-consuming for mass production but very suitable for laboratory experimentation.

However, new therapeutic products, based on responsive nanomaterials, such as the ultradeformable, stress-sensitive Transfersome vesicles, are under development and already approved for human use in some countries.

Nanotech Manufacturing and Its Products

As of August 21, 2008, the Project on Emerging Nanotechnologies estimates that over 800 manufacturer-identified nanotech products are publicly available, with new ones hitting the market at a pace of 3–4 per week.The project lists all of the products in a publicly accessible online. Most applications are limited to the use of "first generation" passive nanomaterials which includes titanium dioxide in sunscreen, cosmetics and some food products; Carbon allotropes used to produce gecko tape; silver in food packaging, clothing, disinfectants and household appliances; zinc oxide in sunscreens and cosmetics, surface coatings, paints and outdoor furniture varnishes; and cerium oxide as a fuel catalyst.

The National Science Foundation (a major distributor for nanotechnology research in the United States) funded researcher David Berube to study the field of nanotechnology. His findings are published in the monograph Nano-Hype: The Truth Behind the Nanotechnology Buzz.This study concludes that much of what is sold as “nanotechnology” is in fact a recasting of straightforward materials science, which is leading to a “nanotech industry built solely on selling nanotubes, nanowires, and the like” which will “end up with a few suppliers selling low margin products in huge volumes." Further applications which require actual manipulation or arrangement of nanoscale components await further research. Though technologies branded with the term 'nano' are sometimes little related to and fall far short of the most ambitious and transformative technological goals of the sort in molecular manufacturing proposals, the term still connotes such ideas. According to Berube, there may be a danger that a "nano bubble" will form, or is forming

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already, from the use of the term by scientists and entrepreneurs to garner funding, regardless of interest in the transformative possibilities of more ambitious and far-sighted work.

If it can be done safely, widespread use of molecular manufacturing looks like a very good idea for the following reasons:

The ability to produce duplicate manufacturing systems means that manufacturing capacity could be doubled almost for free.A single, self-contained, clean-running personal nanofactory could produce a vast range of strong, efficient, carbon-based products as they are needed.Emergency and humanitarian aid could be supplied quickly and cheaply.Many of the environmental pressures caused by our current technology base could be mitigated or removed entirely.The rapid and flexible manufacturing cycle will allow many innovations to be developed rapidly.

Although a complete survey and explanation of the potential benefits of nanotechnology is beyond the scope of this paper, it seems clear that the technology has a lot to offer.

All of these advantages should be delivered as far as is consistent with minimizing risks. Humanitarian imperatives and opportunities for profit both demand extensive use of nanotechnology. In addition, failure to use nanotechnology will create a pent-up demand for its advantages, which will virtually guarantee an uncontrollable black market. Once molecular manufacturing has been developed, a second, independent development project would be both far easier and far more dangerous than the original project.

How Nanotechnology will help the Energy Sector

The advent of mobile phones, personal computers, and other electronic devices, along with the miniaturization of technology, necessitates a greater requirement for mobile power sources of longer durability. Nanotechnology ideally suits this need and will manifest itself in two critical areas. First is in the conversion of energy as in a solar cell, and the second is in the storage of electricity in batteries and capacitors. The static nature of electricity generation and storage in these systems ideally suit themselves for nanotechnology application.

A tremendous amount of research is going on in the nanotechnology field, even though only a few items have so far reached the commercial stage. Since the work is at a molecular level, developments require sophisticated facilities that require a lot of time and investment.

Future Trends Unprecedented opportunities are arising for re-engineering existing products. For example,

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cluster of atoms (nanodots, macromolecules), nanocrystalline structured materials (grain size less than 100 nm), fibres less than 100 nm in diameter (nanorods and nanotubes), films less than 100 nm in thickness provide a good base to develop further new nanocomponents and materials.

The buckyball (C60) has opened up a excellent field of chemistry and material science with many exciting applications because of its ability to accept electrons. Carbon nanotubes have shown a promising potential in the safe, effective and risk free storage of hydrogen gas in fuel cells, increasing the prospects of wide uses of fuel cells and replacement of internal combustion engine. The potential of nanotubes can be further exploited in oil and gas industry. The nanotube market is likely to hit 1.35 billion dollars in 2005. Nanotechnology offers a myriad of applications for production of new gas sensors, optical sensors, chemical sensors, and other energy conversion devices to bio implants.

Solar Cells Nanoporous oxide films such as TiO2 are being used to enhance photo voltaic cell technology. Nanoparticles are perfect to absorb solar energy and they can be used in very thin layers on conventional metals to absorb incident solar energy. New solar cells are based on nanoparticles of semi conductors, nanofilms and nanotubes by embedding in a charge transfer medium. Films formed by sintering of nanometric particles of TiO2 (diameter 10-20 nm) combine high surface area, transparency, excellent stability and good electrical conductivity and are ideal for photovoltaic applications. Non porous oxide films are highly promising material for photovoltaic applications. Nanotechnology opens the opportunity to produce cheaper and friendlier solar cells.

Nanofibres In China and U.K., nanocarbon fibres have been produced. The production of nanofibres offers the potential of using the woven reinforcement as body armor. The future soldier’s uniform would incorporate soft woven ultra strong fabric with capabilities to become rigid when a soldier breaks his legs and would protect him against pollution, poisoning and enemy hazards.

Sensors Nanotechnology offers unlimited opportunities to produce new generation pressure, chemical, magneto resistive and anti-collision automobile sensors. Many of the novel applications such as new sensors, better photovoltaic cells, lighter and strong materials for defense, aerospace and automotives are already in use, and applications such as anti-corrosion coating, tougher and harder cutting tools, and medical implants and chips with 1 nm features may be developed in another 5-15 years. Nanostructured materials for nanoelectronic components, ultra fast processors, nanorobots for body parts are still in the state of infancy.

Spending and Investment Despite the hype surrounding nanotechnology, the progress achieved in the last five years is remarkable as shown by dramatic public spending in recent years. The total global investment in

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nanotechnology is currently around 5 billion euros, two billion of which comes from the private sector.

Ultra Light Materials Nanotechnology is viewed as a key technology for the development of ultra light materials which would result in energy, fuel and materials savings and development of spectacular materials with complete control over structure and properties at a subatomic level not hitherto known to scientists and engineers. With the future development of nanocatalyst, diesel oxidant using nanoscale layers of Pt, Pd, the major environmental killers smog, pollution and toxic pesticide would be eliminated and humans will be able to breathe in healthy air. Improvement in nanofilters would enable bacteria less than 30 nm to be filtered and achieve water purity of 99.999997.

Corrosion and Corrosion Prevention Despite the progress in understanding the structure of nanomaterials, there is no evidence to show that nanomaterials are more resistant to corrosion than their conventional counterparts. A typical feature of nanomaterials is the defect core structure, which is caused by incorporation of vacancies, dislocations, grains or interphase boundaries, which alter the density and conduction in defect core regions where 50% of the atoms are located. All misfits are concentrated in the grain boundary. The grain boundary is associated with high diffusivity and higher electrical resistivity. Solute atoms with little solubility also segregate into the boundary regions. Summing up, the grain boundary region is highly active in nanomaterials. Nanograin size, enhanced diffusivity and concentration of defects would make grain boundary sensitive to attack by corrosion. Increased electrical resistivity due to electron scattering would enhance corrosion resistance. Increased number of grain boundaries would also lead to development of more anodic sites for nucleation of corrosion. Theoretically, the structural evidence does not present an optimistic picture of corrosion resistance.

Using Nanotechnology Safely A safe personal nanofactory design must build approved products, while refusing to build unapproved products. It must also be extremely tamper-resistant; if anyone found a way to build unapproved products, they could make an unrestricted, unsafe nanofactory, and distribute copies of it. The product approval process must also be carefully designed, to maximize the benefits of the technology while minimizing the risk of misuse. Restricted nanofactories avoid the extreme risk/benefit tradeoff of other nanotechnology administration plans, but they do require competent administration.

Current cryptographic techniques permit verification and encryption of communication over an unsecured link. These are used in smart cards and digital cellular phones, and will soon be used in digital rights management. Using such techniques, each personal nanofactory would be able to

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verify that it was in communication with the central library. Only designs from the library could be manufactured. In addition, each design could come with a set of restrictions. For example, medical tools might only be manufactured at the request of a doctor. Commercial designs could require payment from a user.

Product Design Parameters Rapid innovation is a key benefit of nanotechnology. The rapid and flexible manufacturing process allows a design to be built and tested almost immediately. Because designers of nano-built products do not have to do any actual nanotechnology research, a high level of innovation can be accommodated without giving designers any access to dangerous kinds of products. As mentioned above, a design with billion-atom, sub-micron blocks—permitting specification of near-biological levels of complexity—would still pose no risk of illicit self-replication. The minimum building block size in a design could be restricted by the design system. A fully automated evaluation and approval process could also consider the energy and power contained in the design, its mechanical integrity, and the amount of computer power built in. The block-based design system provides a simple interface to the block-based convergent assembly system. A variety of design systems could be implemented using the same nanofactory hardware, and the designer would not have to become an expert on the process of construction to create buildable designs.

Conclusion

Nanotechnology offers the ability to build large numbers of products that are incredibly powerful by today's standards. This possibility creates both opportunity and risk. The problem of minimizing the risk is not simple; excessive restriction creates black markets, which in this context implies unrestricted nanofabrication. Selecting the proper level of restriction is likely to pose a difficult challenge.

This paper describes a system that allows the risk to be dealt with on two separate fronts: control of the molecular manufacturing capacity, and control of the products. Such a system has many advantages. A well-controlled manufacturing system can be widely deployed, allowing distributed, cheap, high-volume manufacturing of useful products and even a degree of distributed innovation. The range of possible nanotechnology-built products is almost infinite. Even if allowable products were restricted to a small subset of possible designs, it would still allow an explosion of creativity and functionality.

In addition to preventing the creation of unrestricted molecular manufacturing devices, further regulation will be necessary to preserve the interests of existing commercial and military institutions. For example, the effects of networked computers on intellectual property rights have

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created concern in several industries and the ability to fabricate anything will surely increase the problem. National security will demand limits on the weapons that can be produced.

This paper has outlined a scenario for the safe development and use of advanced nanotechnological manufacturing. Unrestricted molecular manufacturing creates several high-stakes risks. The use of a restricted nanofactory design that is safe for widespread deployment can mitigate some of these risks, and other risks can be dealt with piecemeal by making many low-stakes decisions about the factory's products. Careful attention must be paid to security during the initial nanofactory development, and wise administration must be implemented to prevent both undesired products and pressure for black markets or independent development. With these caveats, however, the system presented here preserves almost all the benefits of unrestricted nanotechnology while greatly reducing the associated risks.

 Health and environmental concerns

Some of the recently developed nanoparticle products may have unintended consequences. Researchers have discovered that silver nanoparticles used in socks only to reduce foot odor are being released in the wash with possible negative consequences.Silver nanoparticles, which are bacteriostatic, may then destroy beneficial bacteria which are important for breaking down organic matter in waste treatment plants or farms.

A study at the University of Rochester found that when rats breathed in nanoparticles, the particles settled in the brain and lungs, which led to significant increases in biomarkers for inflammation and stress response. A study in China indicated that nanoparticles induce skin aging through oxidative stress in hairless mice.

A major study published more recently in Nature Nanotechnology suggests some forms of carbon nanotubes – a poster child for the “nanotechnology revolution” – could be as harmful as asbestos if inhaled in sufficient quantities. Anthony Seaton of the Institute of Occupational Medicine in Edinburgh, Scotland, who contributed to the article on carbon nanotubes said "We know that some of them probably have the potential to cause mesothelioma. So those sorts of materials need to be handled very carefully." In the absence of specific nano-regulation forthcoming from governments, Paull and Lyons (2008) have called for an exclusion of engineered nanoparticles from organic food. A newspaper article reports that workers in a paint factory developed serious lung disease and nanoparticles were found in their lungs.

RegulationCalls for tighter regulation of nanotechnology have occurred alongside a growing debate related to the human health and safety risks associated with nanotechnology.Furthermore, there is significant debate about who is responsible for the regulation of nanotechnology. While some non-nanotechnology specific regulatory agencies currently cover some products and processes

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(to varying degrees) – by “bolting on” nanotechnology to existing regulations – there are clear gaps in these regimes. In "Nanotechnology Oversight: An Agenda for the Next Administration," former EPA deputy administrator J. Clarence (Terry) Davies lays out a clear regulatory roadmap for the next presidential administration and describes the immediate and longer term steps necessary to deal with the current shortcomings of nanotechnology oversight.

Stakeholders concerned by the lack of a regulatory framework to assess and control risks associated with the release of nanoparticles and nanotubes have drawn parallels with bovine spongiform encephalopathy (‘mad cow’s disease), thalidomide, genetically modified food, nuclear energy, reproductive technologies, biotechnology, and asbestosis. Dr. Andrew Maynard, chief science advisor to the Woodrow Wilson Center’s Project on Emerging Nanotechnologies, concludes (among others) that there is insufficient funding for human health and safety research, and as a result there is currently limited understanding of the human health and safety risks associated with nanotechnology.

The Royal Society report identified a risk of nanoparticles or nanotubes being released during disposal, destruction and recycling, and recommended that “manufacturers of products that fall under extended producer responsibility regimes such as end-of-life regulations publish procedures outlining how these materials will be managed to minimize possible human and environmental exposure” Reflecting the challenges for ensuring responsible life cycle regulation, the Institute for Food and Agricultural Standards has proposed standards for nanotechnology research and development should be integrated across consumer, worker and environmental standards. They also propose that NGOs and other citizen groups play a meaningful role in the development of these standards.

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REFRENCES

Through news paper articles

Internet

Through books