ABSTRACT:
Nanotechnology is an anticipated manufacturing technology giving
thorough, inexpensive control of the structure of matter. The term has
sometimes been used to refer to any technique able to work at a
submicron scale. Nanotechnology is sometimes called molecular
nanotechnology, which means basically "A place for every atom and every
atom in its place." (other terms, such as molecular engineering,
molecular manufacturing, etc. are also often applied). Molecular
manufacturing will enable the construction of giga-ops computers smaller
than a cubic micron; cell repair machines; personal manufacturing and
recycling appliances; and much more.
Nano-technology mainly consists of the processing of, separation,
consolidation, and deformation of materials by one atom or one molecule.
Nanotechnology is often referred to as a general-purpose technology.
That's because in its advanced form it will have significant impact on
almost all industries and all areas of society. It offers better built,
longer lasting, cleaner, safer, and smarter products for the home, for
communications, for medicine, for transportation, for agriculture, and
for industry in general.
The present paper gives an overview on NANOTECHNOLOGY.
DEFINITION:
Nanotechnology is the technology which exploits phenomena and structures
that can only occur at the nanometer scale, which is the scale of
single atoms and small molecules.
The United States' National Nanotechnology Initiative defines it as follows: "Nanotechnology is the understanding and control of matter at dimensions of roughly 1 to 100 nanometers (for comparision, a human hair is 80000 nanometers wide), where unique phenomena enable novel applications." Such phenomena include quantum confinement--which can result in different electromagnetic and optical properties of a material between nanoparticles and the bulk material; the Gibbs-Thomson effect--which is the lowering of the melting point of a material when it is nanometers in size; and such structures including carbon nanotubes. Nanoscience and nanotechnology are an extension of the field of materials science, and materials science departments at universities around the world in conjunction with Physics, mechanical engineering, bioengineering, and chemical engineering departments are leading the breakthroughs in nanotechnology. Broadly speaking, the central thesis of nanotechnology is that almost any chemically stable structure that can be specified can in fact be built. R.P.FEYNMAN ERICDREXLER The first mention of some of the distinguishing concepts in nanotechnology (but predating 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 Caltech on December 29, 1959 when he said: "The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom." (Feynman won the 1965 Nobel prize in physics). 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, 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 more important, etc. This basic idea appears feasible, and exponential assembly enhances it with parallelism to produce a useful quantity of end products. Nanoscience is the study of effects while nanotechnology is more about fabrication. HISTORY As mentioned earlier, the idea was first initiated by Richard Feynman in 1959. In the 1980s the basic idea of this definition was explored in much more depth by Dr. 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 and Nanosystems: Molecular Machinery, Manufacturing, and Computation, and so the term acquired its current sense. More broadly, nanotechnology includes the many techniques used to create structures at a size scale below 100 nm, including those used for fabrication of nanowires, those used in semiconductor fabrication such as deep ultraviolet lithography, electron beam lithography, focused ion beam machining, Nanoimprint Lithography atomic layer deposition, and molecular vapor deposition, and further including molecular self-assembly techniques such as those employing di-block copolymers. It should be noted, however, that all of these techniques preceeded the nanotech era, and are extensions in the development of scientific advancements rather than techniques which were devised with the sole purpose of creating nanotechnology or which were results of nanotechnology research. The term nanotechnology is sometimes conflated with the more specific molecular nanotechnology (also known as "MNT"), a proposed form of advanced nanotechnology based on productive nanosystems. Molecular nanotechnology would fabricate precise structures using mechanosynthesis to perform molecular manufacturing. Molecular nanotechnology, though not yet extant, is expected to have a great impact on society if realized. In August 2005, a task force consisting of 50+ international experts from various fields was organized by the Center for Responsible Nanotechnology to study the societal implications of molecular nanotechnology. NANOTECH MANUFACTURING AND ITS PRODUCTS A machine capable of molecular manufacturing—whether nanoscale or macro scale—has two possible functions: to create more manufacturing capacity by duplicating itself, and to manufacture products. Most products created by molecular manufacturing will not possess any capacity for self-duplication, or indeed for manufacturing of any kind; as a result, each product can be evaluated on its own merits, without worrying about special risks. A nanotechnology-based manufacturing system, on the other hand, could build weapons, gray goo, or anything else it was programmed to produce. The solution, then, is to regulate nanofactories; products are far less dangerous. A nanotechnology-built car could no more turn into gray goo than a steel-and-plastic car could. Some products, however, will be powerful enough to require restriction. Weapons built by nanotechnology would be far more effective than today's versions. Very small products could get lost and cause nano-litter, or be used to spy undetectably on people. And a product that included a general molecular manufacturing capability would be, effectively, an unregulated nanofactory—horrifyingly dangerous in the wrong hands. Any widespread use of nanotechnology manufacturing must include the ability to restrict, somehow, the range of products that can be produced. 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 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. Development of nanotechnology must be undertaken with care to avoid accidents; once a nanotechnology-based manufacturing technology is created, it must be administered with even more care. Irresponsible use of molecular manufacturing could lead to black markets, unstable arms races ending in immense destruction, and possibly a release of gray goo. Misuse of the technology by inhumane governments, terrorists, criminals, and irresponsible users could produce even worse problems—gray goo is a feeble weapon compared to what could be designed. It seems likely that research leading to advanced nanotechnology will have to be carefully monitored and controlled. Once designed and built, a product of molecular manufacturing could be used by consumers just like a steel or plastic product. Of course, some products, such as cars, knives, and nail guns, are dangerous by design, but this kind of danger is one that we already know how to deal with. In the United States, Underwriter's Laboratories (UL), the Food and Drug Administration, and a host of industry and consumer organizations work to ensure that our products are as safe as we expect them to be. Nanotechnology products could be regulated in the same way. And if a nanofactory could only make approved products, it could be widely distributed, even for home use, without introducing any special risks. NANOFACTORY The power of nanotechnology can be encapsulated in an apparently simple device called a nanofactory that may sit on your countertop or desktop. Packed with miniature chemical processors, computing, and robotics, it will produce a wide-range of items quickly, cleanly, and inexpensively, building products directly from blueprints. Nanotechnology not only will allow making many high-quality products at very low cost, but it will allow making new nanofactories at the same low cost and at the same rapid speed. This unique (outside of biology that is) ability to reproduce its own means of production is why nanotech is said to be an exponential technology. It represents a manufacturing system that will be able to make more manufacturing systems—factories that can build factories—rapidly, cheaply, and cleanly. The means of production will be able to reproduce exponentially, so in just a few weeks a few nanofactories conceivably could become billions. It is a revolutionary, transformative, powerful, and potentially very dangerous—or beneficial—technology. SOME OF THE DEVICES Bacterial motors could inspire nanotechnology BACTERIAL FLAGELLAR MOTOR 'The bacterial flagellar motor is an example of finished bio-nanotechnology, and understanding how it works and assembles is one of the first steps towards making man-made machines on the same tiny scale. 'The smallest man-made rotary motors so far are thousands of times bigger.' This motor has the same power-to-weight ratio as an internal combustion engine, spins at up to 100,000 rpm and achieves near-perfect efficiency. Yet at only 50 nanometers across, one hundred million would fit onto a full-stop. The only other natural rotary electric motor is in the enzyme ATP-syntheses. Way to Use Metal in Micro machines In the world of micro technology, entire "machines," so tiny the naked eye can't see them, can be manufactured to create things like sensors that deploy car air bags. But conventional micro machine fabrication technologies have been based on silicon, limiting them when it comes to making complex, three-dimensional structures. Image: Left, a gold-coated chain; each link is 70 microns long. Right, electron micrograph of a copper-coated, 16-turn acrylic inductor with a meth acrylic support. Adding Nanotubes Makes Ordinary Materials Absorb Vibration A new study suggests that integrating nanotubes into traditional materials dramatically improves their ability to reduce vibration, especially at high temperatures. The findings could pave the way for a new class of materials with a multitude of applications, from high-performance parts for spacecraft and automobile engines, to golf clubs that don’t sting and stereo speakers that don’t buzz. Image: From left to right, an untreated sample of polymer material, the new nano-composite, and a scanning electron microscopy image showing the nanotubes dispersed in the polymer resin. 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. 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. APPLICATIONS OF NANOTECHNOLOGY IN SPACE DEVELOPMENTS AND SYSTEMS The images - as well as the whole concept of miniature satellites - are relevant to nanotechnology because of the scale of some of the current and future generations of components, which enable shrinking and weight reduction, while at the same time increasing the sophistication of each sat. The "Pico satellites" each weigh less than one-half-pound and are actually slighty larger than a deck of cards (see image above) -- they are not Pico scale themselves. They do, however, contain MEMS systems, for systematic testing and use in space. "Although the basic mission of picosats is to serve as a platform for testing miniature devices such as MEMS, they also serve as a link to nanosatellites, slightly larger than picosats and envisioned as tiny workhorses of the future." These "nanosatellites" will be 1 to 10 kilograms, and could be operational within five to ten years. They also will not be A nanosatellite in orbit. Picosatellites, less than one-half pound each, are shown against a coffee mug. nanoscale, but will carry MEMS and possibly NEMS components. To further clarify the naming: "Satellites are classified according to weight. Picosats are under one kilogram (2.2 pounds equal a kilogram), while nanosatellites range from 1 to 10 kilograms. Other classes are microsats, 10 to 100 kilograms; small sats, 100 to 1,000 kilograms; and standard satellites, 1,000 kilograms or more. The smallest category envisioned is the femtosat, less than one-tenth of a kilogram, a satellite that would handle very simple missions." APPLICATIONS IN MEDICINE An application: killing cancer cells Given such molecular tools, we could design a small device able to identify and kill cancer cells. The device would have a small computer, several binding sites to determine the concentration of specific molecules, and a supply of some poison which could be selectively released and was able to kill a cell identified as cancerous. The cancer killer could thus determine that it was located in (say) the big toe. If the objective was to kill a colon cancer, the cancer killer in the big toe would not release its poison. Very precise control over location of the cancer killer's activities could thus be achieved. The cancer killer could readily be reprogrammed to attack different targets (and could, in fact, be reprogrammed via acoustic signals transmitted while it was in the body). This general architecture could provide a flexible method of destroying unwanted structures (bacterial infestations, etc). An application: providing oxygen A second application would be to provide metabolic support in the event of impaired circulation. Poor blood flow, caused by a variety of conditions, can result in serious tissue damage. A major cause of tissue damage is inadequate oxygen. A simple method of improving the levels of available oxygen despite reduced blood flow would be to provide an "artificial red blood cell." As oxygen is being absorbed by our artificial red blood cells in the lungs at the same time that carbon dioxide is being released, and oxygen is being released in the tissues when carbon dioxide is being absorbed, the energy needed to compress one gas can be provided by decompressing the other. The power system needs only makeup for losses caused by inefficiencies in this process. These losses could presumably be made small, thus allowing our artificial red blood cells to operate with little energy consumption. An application: artificial mitochondria While providing oxygen to healthy tissue should maintain metabolism, tissues already suffering from ischemic injury (tissue injury caused by loss of blood flow) might no longer be able to properly metabolize oxygen. In particular, the mitochondria will, at some point, fail. Increased oxygen levels in the presence of nonfunctional or partially functional mitochondria will be ineffective in restoring the tissue. However, more direct metabolic support could be provided. The direct release of ATP, coupled with selective release or absorption of critical metabolites (using the kind of selective transport system mentioned earlier), should be effective in restoring cellular function even when mitochondrial function had been compromised. The devices restoring metabolite levels, injected into the body, should be able to operate autonomously for many hours (depending on power requirements, the storage capacity of the device and the release and uptake rates required to maintain metabolite levels). EFFECTS OF MOLECULAR MANUFACTURING Molecular nanotechnology (MNT) will be a significant breakthrough, comparable perhaps to the Industrial Revolution—but compressed into a few years. This has the potential to disrupt many aspects of society and politics. The power of the technology may cause two competing nations to enter a disruptive and unstable arms race. Weapons and surveillance devices could be made small, cheap, powerful, and very numerous. Cheap manufacturing and duplication of designs could lead to economic upheaval. Overuse of inexpensive products could cause widespread environmental damage. Attempts to control these and other risks may lead to abusive restrictions, or create demand for a black market that would be very risky and almost impossible to stop; small nanofactories will be very easy to smuggle, and fully dangerous. There are numerous severe risks—including several different kinds of risk—that cannot all be prevented with the same approach. Simple, one-track solutions cannot work. The right answer is unlikely to evolve without careful planning. The potential benefits of molecular manufacturing are immense, but so are the dangers. In order to avert the dangers, we must thoroughly understand them, and then develop comprehensive plans to prevent them. As explained in our Timeline and Products pages, molecular nanotechnology (MNT) will allow the rapid prototyping and inexpensive manufacture of a wide variety of powerful products. This capability will arrive rather suddenly, since the final steps of developing the technology are likely to be much easier than the initial steps, and many of them can be pre-planned. The sudden arrival of molecular manufacturing may not allow time to adjust to its implications. Adequate preparation is essential. WHERE IS NANOTECHNOLOGY GOING? Nanotech knowledge is rapidly growing. The number of scientific publications in the field grew from about 200 in 1997 to more than 12,000 in 2002. Despite this, relatively few products using nanoparticles are currently on the market. On the whole, the ones that are already on sale do not address the issues highlighted above, of health, food security and the environment. Rather, they have focused on consumer applications that include improved sunscreens, crack-resistant paints and scratch-proof spectacle lenses. Like electricity and the internal combustion engine, nanotechnology is an enabling technology. As such, it is predicted to precipitate a range of innovations. 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. 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. So this paper outlines a precise definition of Nanotechnology and mainly stresses on Molecular Manufacturing Technology. REFERENCES • Daniel J. Shanefield (1996). Organic Additives And Ceramic Processing, Kluwer Academic Publishers. • Hunt, Geoffrey & Mehta, Michael (eds) (2006). Nanotechnology: Risk Ethics, & Law, Earthscan, London. • www.nanotechnologynow.com • www.google.co.in
The United States' National Nanotechnology Initiative defines it as follows: "Nanotechnology is the understanding and control of matter at dimensions of roughly 1 to 100 nanometers (for comparision, a human hair is 80000 nanometers wide), where unique phenomena enable novel applications." Such phenomena include quantum confinement--which can result in different electromagnetic and optical properties of a material between nanoparticles and the bulk material; the Gibbs-Thomson effect--which is the lowering of the melting point of a material when it is nanometers in size; and such structures including carbon nanotubes. Nanoscience and nanotechnology are an extension of the field of materials science, and materials science departments at universities around the world in conjunction with Physics, mechanical engineering, bioengineering, and chemical engineering departments are leading the breakthroughs in nanotechnology. Broadly speaking, the central thesis of nanotechnology is that almost any chemically stable structure that can be specified can in fact be built. R.P.FEYNMAN ERICDREXLER The first mention of some of the distinguishing concepts in nanotechnology (but predating 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 Caltech on December 29, 1959 when he said: "The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom." (Feynman won the 1965 Nobel prize in physics). 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, 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 more important, etc. This basic idea appears feasible, and exponential assembly enhances it with parallelism to produce a useful quantity of end products. Nanoscience is the study of effects while nanotechnology is more about fabrication. HISTORY As mentioned earlier, the idea was first initiated by Richard Feynman in 1959. In the 1980s the basic idea of this definition was explored in much more depth by Dr. 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 and Nanosystems: Molecular Machinery, Manufacturing, and Computation, and so the term acquired its current sense. More broadly, nanotechnology includes the many techniques used to create structures at a size scale below 100 nm, including those used for fabrication of nanowires, those used in semiconductor fabrication such as deep ultraviolet lithography, electron beam lithography, focused ion beam machining, Nanoimprint Lithography atomic layer deposition, and molecular vapor deposition, and further including molecular self-assembly techniques such as those employing di-block copolymers. It should be noted, however, that all of these techniques preceeded the nanotech era, and are extensions in the development of scientific advancements rather than techniques which were devised with the sole purpose of creating nanotechnology or which were results of nanotechnology research. The term nanotechnology is sometimes conflated with the more specific molecular nanotechnology (also known as "MNT"), a proposed form of advanced nanotechnology based on productive nanosystems. Molecular nanotechnology would fabricate precise structures using mechanosynthesis to perform molecular manufacturing. Molecular nanotechnology, though not yet extant, is expected to have a great impact on society if realized. In August 2005, a task force consisting of 50+ international experts from various fields was organized by the Center for Responsible Nanotechnology to study the societal implications of molecular nanotechnology. NANOTECH MANUFACTURING AND ITS PRODUCTS A machine capable of molecular manufacturing—whether nanoscale or macro scale—has two possible functions: to create more manufacturing capacity by duplicating itself, and to manufacture products. Most products created by molecular manufacturing will not possess any capacity for self-duplication, or indeed for manufacturing of any kind; as a result, each product can be evaluated on its own merits, without worrying about special risks. A nanotechnology-based manufacturing system, on the other hand, could build weapons, gray goo, or anything else it was programmed to produce. The solution, then, is to regulate nanofactories; products are far less dangerous. A nanotechnology-built car could no more turn into gray goo than a steel-and-plastic car could. Some products, however, will be powerful enough to require restriction. Weapons built by nanotechnology would be far more effective than today's versions. Very small products could get lost and cause nano-litter, or be used to spy undetectably on people. And a product that included a general molecular manufacturing capability would be, effectively, an unregulated nanofactory—horrifyingly dangerous in the wrong hands. Any widespread use of nanotechnology manufacturing must include the ability to restrict, somehow, the range of products that can be produced. 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 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. Development of nanotechnology must be undertaken with care to avoid accidents; once a nanotechnology-based manufacturing technology is created, it must be administered with even more care. Irresponsible use of molecular manufacturing could lead to black markets, unstable arms races ending in immense destruction, and possibly a release of gray goo. Misuse of the technology by inhumane governments, terrorists, criminals, and irresponsible users could produce even worse problems—gray goo is a feeble weapon compared to what could be designed. It seems likely that research leading to advanced nanotechnology will have to be carefully monitored and controlled. Once designed and built, a product of molecular manufacturing could be used by consumers just like a steel or plastic product. Of course, some products, such as cars, knives, and nail guns, are dangerous by design, but this kind of danger is one that we already know how to deal with. In the United States, Underwriter's Laboratories (UL), the Food and Drug Administration, and a host of industry and consumer organizations work to ensure that our products are as safe as we expect them to be. Nanotechnology products could be regulated in the same way. And if a nanofactory could only make approved products, it could be widely distributed, even for home use, without introducing any special risks. NANOFACTORY The power of nanotechnology can be encapsulated in an apparently simple device called a nanofactory that may sit on your countertop or desktop. Packed with miniature chemical processors, computing, and robotics, it will produce a wide-range of items quickly, cleanly, and inexpensively, building products directly from blueprints. Nanotechnology not only will allow making many high-quality products at very low cost, but it will allow making new nanofactories at the same low cost and at the same rapid speed. This unique (outside of biology that is) ability to reproduce its own means of production is why nanotech is said to be an exponential technology. It represents a manufacturing system that will be able to make more manufacturing systems—factories that can build factories—rapidly, cheaply, and cleanly. The means of production will be able to reproduce exponentially, so in just a few weeks a few nanofactories conceivably could become billions. It is a revolutionary, transformative, powerful, and potentially very dangerous—or beneficial—technology. SOME OF THE DEVICES Bacterial motors could inspire nanotechnology BACTERIAL FLAGELLAR MOTOR 'The bacterial flagellar motor is an example of finished bio-nanotechnology, and understanding how it works and assembles is one of the first steps towards making man-made machines on the same tiny scale. 'The smallest man-made rotary motors so far are thousands of times bigger.' This motor has the same power-to-weight ratio as an internal combustion engine, spins at up to 100,000 rpm and achieves near-perfect efficiency. Yet at only 50 nanometers across, one hundred million would fit onto a full-stop. The only other natural rotary electric motor is in the enzyme ATP-syntheses. Way to Use Metal in Micro machines In the world of micro technology, entire "machines," so tiny the naked eye can't see them, can be manufactured to create things like sensors that deploy car air bags. But conventional micro machine fabrication technologies have been based on silicon, limiting them when it comes to making complex, three-dimensional structures. Image: Left, a gold-coated chain; each link is 70 microns long. Right, electron micrograph of a copper-coated, 16-turn acrylic inductor with a meth acrylic support. Adding Nanotubes Makes Ordinary Materials Absorb Vibration A new study suggests that integrating nanotubes into traditional materials dramatically improves their ability to reduce vibration, especially at high temperatures. The findings could pave the way for a new class of materials with a multitude of applications, from high-performance parts for spacecraft and automobile engines, to golf clubs that don’t sting and stereo speakers that don’t buzz. Image: From left to right, an untreated sample of polymer material, the new nano-composite, and a scanning electron microscopy image showing the nanotubes dispersed in the polymer resin. 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. 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. APPLICATIONS OF NANOTECHNOLOGY IN SPACE DEVELOPMENTS AND SYSTEMS The images - as well as the whole concept of miniature satellites - are relevant to nanotechnology because of the scale of some of the current and future generations of components, which enable shrinking and weight reduction, while at the same time increasing the sophistication of each sat. The "Pico satellites" each weigh less than one-half-pound and are actually slighty larger than a deck of cards (see image above) -- they are not Pico scale themselves. They do, however, contain MEMS systems, for systematic testing and use in space. "Although the basic mission of picosats is to serve as a platform for testing miniature devices such as MEMS, they also serve as a link to nanosatellites, slightly larger than picosats and envisioned as tiny workhorses of the future." These "nanosatellites" will be 1 to 10 kilograms, and could be operational within five to ten years. They also will not be A nanosatellite in orbit. Picosatellites, less than one-half pound each, are shown against a coffee mug. nanoscale, but will carry MEMS and possibly NEMS components. To further clarify the naming: "Satellites are classified according to weight. Picosats are under one kilogram (2.2 pounds equal a kilogram), while nanosatellites range from 1 to 10 kilograms. Other classes are microsats, 10 to 100 kilograms; small sats, 100 to 1,000 kilograms; and standard satellites, 1,000 kilograms or more. The smallest category envisioned is the femtosat, less than one-tenth of a kilogram, a satellite that would handle very simple missions." APPLICATIONS IN MEDICINE An application: killing cancer cells Given such molecular tools, we could design a small device able to identify and kill cancer cells. The device would have a small computer, several binding sites to determine the concentration of specific molecules, and a supply of some poison which could be selectively released and was able to kill a cell identified as cancerous. The cancer killer could thus determine that it was located in (say) the big toe. If the objective was to kill a colon cancer, the cancer killer in the big toe would not release its poison. Very precise control over location of the cancer killer's activities could thus be achieved. The cancer killer could readily be reprogrammed to attack different targets (and could, in fact, be reprogrammed via acoustic signals transmitted while it was in the body). This general architecture could provide a flexible method of destroying unwanted structures (bacterial infestations, etc). An application: providing oxygen A second application would be to provide metabolic support in the event of impaired circulation. Poor blood flow, caused by a variety of conditions, can result in serious tissue damage. A major cause of tissue damage is inadequate oxygen. A simple method of improving the levels of available oxygen despite reduced blood flow would be to provide an "artificial red blood cell." As oxygen is being absorbed by our artificial red blood cells in the lungs at the same time that carbon dioxide is being released, and oxygen is being released in the tissues when carbon dioxide is being absorbed, the energy needed to compress one gas can be provided by decompressing the other. The power system needs only makeup for losses caused by inefficiencies in this process. These losses could presumably be made small, thus allowing our artificial red blood cells to operate with little energy consumption. An application: artificial mitochondria While providing oxygen to healthy tissue should maintain metabolism, tissues already suffering from ischemic injury (tissue injury caused by loss of blood flow) might no longer be able to properly metabolize oxygen. In particular, the mitochondria will, at some point, fail. Increased oxygen levels in the presence of nonfunctional or partially functional mitochondria will be ineffective in restoring the tissue. However, more direct metabolic support could be provided. The direct release of ATP, coupled with selective release or absorption of critical metabolites (using the kind of selective transport system mentioned earlier), should be effective in restoring cellular function even when mitochondrial function had been compromised. The devices restoring metabolite levels, injected into the body, should be able to operate autonomously for many hours (depending on power requirements, the storage capacity of the device and the release and uptake rates required to maintain metabolite levels). EFFECTS OF MOLECULAR MANUFACTURING Molecular nanotechnology (MNT) will be a significant breakthrough, comparable perhaps to the Industrial Revolution—but compressed into a few years. This has the potential to disrupt many aspects of society and politics. The power of the technology may cause two competing nations to enter a disruptive and unstable arms race. Weapons and surveillance devices could be made small, cheap, powerful, and very numerous. Cheap manufacturing and duplication of designs could lead to economic upheaval. Overuse of inexpensive products could cause widespread environmental damage. Attempts to control these and other risks may lead to abusive restrictions, or create demand for a black market that would be very risky and almost impossible to stop; small nanofactories will be very easy to smuggle, and fully dangerous. There are numerous severe risks—including several different kinds of risk—that cannot all be prevented with the same approach. Simple, one-track solutions cannot work. The right answer is unlikely to evolve without careful planning. The potential benefits of molecular manufacturing are immense, but so are the dangers. In order to avert the dangers, we must thoroughly understand them, and then develop comprehensive plans to prevent them. As explained in our Timeline and Products pages, molecular nanotechnology (MNT) will allow the rapid prototyping and inexpensive manufacture of a wide variety of powerful products. This capability will arrive rather suddenly, since the final steps of developing the technology are likely to be much easier than the initial steps, and many of them can be pre-planned. The sudden arrival of molecular manufacturing may not allow time to adjust to its implications. Adequate preparation is essential. WHERE IS NANOTECHNOLOGY GOING? Nanotech knowledge is rapidly growing. The number of scientific publications in the field grew from about 200 in 1997 to more than 12,000 in 2002. Despite this, relatively few products using nanoparticles are currently on the market. On the whole, the ones that are already on sale do not address the issues highlighted above, of health, food security and the environment. Rather, they have focused on consumer applications that include improved sunscreens, crack-resistant paints and scratch-proof spectacle lenses. Like electricity and the internal combustion engine, nanotechnology is an enabling technology. As such, it is predicted to precipitate a range of innovations. 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. 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. So this paper outlines a precise definition of Nanotechnology and mainly stresses on Molecular Manufacturing Technology. REFERENCES • Daniel J. Shanefield (1996). Organic Additives And Ceramic Processing, Kluwer Academic Publishers. • Hunt, Geoffrey & Mehta, Michael (eds) (2006). Nanotechnology: Risk Ethics, & Law, Earthscan, London. • www.nanotechnologynow.com • www.google.co.in
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