NANOTECH1 by gopishrine





The goal of this paper is to explain what Nanotechnologies are and to present in a succinct manner the essential principal notions on the subject, and to give an overview of the perspectives and issues which will undoubtedly present themselves in the years to come. Impact of the new Tech. in the fields of manufacturing, medicine, environment and defense will be unprecedented and much beyond our present scope of imagination. The definition of Nanotechnology in itself is controversial and we have based our definition on the notions currently held by the professionals in the field. The paper presents the various fields in which this futuristic technology can be applied and its impact on the entire human race. The concept of nanotechnology was first suggested by Richard Feynman and that over 40 years ago and it may still take around a period of 20 years to develop this technology the way it is being seen by the experts in the field all across the globe. Nanotechnology is a logical step, unavoidable in the course of human progress. More than just progress in a narrow realm of technology, this represents the birth process of a new "age" as we harness Nanotechnology’s potential.


Why study Nanotechnology:
A single technology with the programmability and speed of digital computers, the chemical flexibility of biotechnology, the military potential of nuclear technology and the utility of very advanced rapid prototyping will bring many changes. Because nanotechnology gives us an understanding of how structures are made at such a fundamental level (from their atoms up to molecular level) and how their molecular arrangements can be altered to alter the macroscopic properties of a material. It gives us the means to:  Design materials more efficiently .  Produce materials that are more solution-focused and better fitted for their intended purpose .  Develop materials with enhanced properties.  Reduce the consumption of resources both in the pre-manufacture testing phase and in the manufacture of finished products. And this is all enabled by the work involved in gaining a better understanding of fundamental chemical, physical and material phenomena. Although nanotechnology implies working at and understanding matter at the nanoscale, the ultimate aim of nanotechnology is to make improvements to existing large-scale systems, processes and products.

Nanotechnology will affect almost all the aspect of the human life. Nanotechnology will bring together electronic and biological technologies that could yield new materials and devices. For example, new forms of sensors, new protective coatings, and revolutionary new means for electrical energy storage and conversion. Together these technologies will enable us to build sophisticated information networks that will lead to more effective surveillance. Nanotechnology will have impact on Civil, automotive and domestic sector also. The areas of potential applications are multiple, from powerful UV-blocking sunscreens to nano-robots designed to repair at the cellular level. Below is presented a non-exhaustive list of the principal domains which will be affected by developments in Nanotechnology:  Materials: new materials, harder, more durable and resistant, lighter and less expensive.  Electronics: electronic components will become smaller and smaller, allowing the design of more powerful computers.  Energy: a vast increase in the potential of solar energy generation is envisioned  Health and nanobiotechnologies: great expectations are held in the areas of prevention,diagnostics, and treatment..


Types of Nanotechnology :
Two school of classification : 1. Top-Down: From top (larger) to bottom (smaller). Mechanisms and structures are miniaturized to a nanometric scale. This has been the most frequent application of nanotechnology up to this point, in particular in the domain of electronics where miniaturization is preponderant. 2. Bottom-Up: From bottom (smaller) to top (larger). Beginning with a nanometric structure such as a molecule, and through a process of assembly or self-assembly creating a mechanism larger than that with which it begun.

Physics and development :
“The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big.” With these words, in 1959, Nobel Prize winning physicist Richard Feynman introduced the concepts that would eventually be known as nanotechnology. Manufactured products are made from atoms. The properties of those products depend on how those atoms are arranged. The principles of physics do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big. If we rearrange the atoms in coal we can make diamond. If we rearrange the atoms in sand (and add a few other trace elements) we can make computer chips. If we rearrange the atoms in dirt, water and air we can make potatoes. Today’s manufacturing methods are very crude at the molecular level. Casting, grinding, milling and even lithography move atoms in great thundering statistical herds. It's worth pointing out that the word "nanotechnology" has become very popular and is used to describe many types of research where the characteristic dimensions are less than about 1,000 nanometers Exploiting quantum effects : Current electronics relies on components which are able to store and switch between two electronic states, where the two states represent either the number "0" or "1". These states are either voltage or current levels measured at the device outputs. Quantum processing will use quantum states to represent numbers, but the states will be characteristics of atomic particles that affect how they interact with each other. This might lead to new computers, but perhaps more significant is that it might be possible to arrange quantum interactions so that the information can only be extracted by somebody who has a precise knowledge of the particular atomic manipulations used in setting the various states. Thus there is the potential for what is called quantum cryptography. Quantum cryptography could lead to totally secure messaging.


There are two main concepts commonly associated with nanotechnology:   Positional assembly (to get the molecular parts in the right places). Massive parallelism (to keep the costs down).

The need for positional assembly implies an interest in molecular robotics, e.g., robotic devices that are molecular both in their size and precision. These molecular scale positional devices are likely to resemble very small versions of their everyday macroscopic counterparts. Positional assembly is frequently used in normal macroscopic manufacturing today, and provides tremendous advantages One robotic arm assembling molecular parts is going to take a long time to assemble anything large, so we need lots of robotic arms: this is what we mean by massive parallelism. While earlier proposals achieved massive parallelism through self replication, today's best guess is that future molecular manufacturing systems will use some form of convergent assembly. In this process vast numbers of small parts are assembled by vast numbers of small robotic arms into larger parts, those larger parts are assembled by larger robotic arms into still larger parts, and so forth. If the size of the parts doubles at each iteration, we can go from one nanometer parts (a few atoms in size) to one meter parts (almost as big as a person) in only 30 steps. Nanotechnology should let us:
  

Get essentially every atom in the right place. Make almost any structure consistent with the laws of physics that we can specify in molecular detail. Have manufacturing costs not greatly exceeding the cost of the required raw materials and energy.

Self Replicating:
With the present rate of research all round the world there is little doubt that a small self-duplicating system can be built. There is strong theoretical support for basing such a system on mechanochemistry. And given the variety of buckytubes, buckyballs, buckyhorns, and other graphitic and diamondoid shapes that have been manufactured or found in nature, it's likely that a self- duplicating nanoscale machine based on 3D covalent carbon mechanochemistry will be relatively straightforward to design. A goal or milestone of molecular manufacturing is a fabricator - a self-contained mechanical system capable of fabricating duplicates of itself from simple chemicals. Several researchers have investigated the requirements of a fabricator (sometimes referred to as an assembler). A single fabricator is not very useful, since it can only make very small products. However, if a nanofactory containing many fabricators can combine


the tiny products (nanoblocks) into a single large product, the result would be extremely useful. A small and pre-tested set of nanomachines, built into nanoblocks, can be combined in many ways to make a vast array of products. By designing with nanoblocks instead of atoms, a product designer loses little flexibility, and gains simplicity and reliability. Nanoblocks can be fastened together in a process called "convergent assembly." The joining process uses a single motion, requiring only simple robotics, and the joints retain most of the strength of the base material. A single nanoblock is big enough to contain a fabricator, computer, or motor, and small enough to be built by a single fabricator in a

Molecular Nanotechnology (MNT):
Molecular nanotechnology (MNT) is different. The field was initially defined by popular and even fictional portrayals. Often misunderstood or overlooked in discussions of nanotechnology, it is nevertheless a field of active and serious study. A coherent and reliable picture has been built over the last decade of a plausible—and possibly imminent—manufacturing system: a limited molecular nanotechnology (LMNT) based on programmable, mechanically guided carbon-lattice chemistry workstations. Such a manufacturing system could make a wide variety of functional molecular shapes, large enough to have stable properties but small enough to make dinosaurs out of today's cutting-edge products. From the beginning, MNT was claimed to be dangerously transformative. It was forewarned that once a general purpose nanoscale manufacturing capability was developed, a flood of diverse and powerful products would appear almost overnight. Distributed, cheap, clean manufacturing would upset many aspects of the economy. Manufacturing systems would be able to duplicate themselves speedily, leading to extremely low capital costs. Such claims seemed fantastic, and this perception has perhaps contributed to the poor reputation of the field. However, work over the past decade has made it clear that many of the initial warnings were justified. Advances in conventional manufacturing are happening continually: parts are getting smaller and more precise, robots are doing more of the fabrication and assembly, inventories are shrinking while speed increases, and industrial processes are producing less waste. The natural destination of these trends is a completely automated manufacturing system that can rapidly build products with atomic precision directly from raw materials, while making use of every molecule. In the normal course of innovation, this might take many decades or even centuries to achieve. However, MNT appears to provide a shortcut: by mixing digital control with chemistry, a mechanochemical system could do for manufacturing what computers have done for information processing. In studying the social impacts of MNT, it is important to know when it might be developed. If it were to be delayed by many decades, its capabilities would not be revolutionary. There is good reason to believe, however, that it could be developed much sooner possibly within 20 yrs.


Fields of study:

Computers: Nanotechnology is a popular research endeavor for people designing
computers because we are getting to the limitations of miniaturization for microprocessors. Nanomanufacturing could allow us to escape the limitations. Nanocomputer chip, assembled out of individual molecules, would be three or four orders of magnitude smaller than those currently being build, and faster as well. The first nanocomputer design will probably be mechanical, utilising a system of rods, pistons and gears, but they won’t be slow due to the short ways inside the logic cells. Using nanomagnetics to store information can extend our current storage density from around sixty gigabytes per square inch to several hundred gigabytes per square inch. And, recent research into light transmitters offers the possibility of exponentially increasing the ease and speed of fiberoptic communication. Also key is creation of a nanocomputer with a capability twice the existing capacity of a full sized computer, within the nanobot itself. Computer parts and sensors may be only a few years away. But this type of nanotechnology simply produces specialized materials and components, one innovation at a time.


Industries: By bonding a molecule with a nanoparticle, or single atom, scientists
are able to create substances such as fullerenes, molecules of carbon atoms that when put together they form tubular fibers, called nanotubes. When those fibers are threaded together and crystallized they can act as metal, but 100 times stronger and four times lighter than steel. Large-scale production of such material would change not only the way automobiles are built, but airplanes and space shuttles as well, even opening the door for civilian space travel through the construction of space elevators. In paint industries the nanoparticles could be incorporated in energy-saving coatings that would help to reduce heat loss by reflecting infra-red radiation, or to produce smart paints that change colour when exposed to changes in temperature or light. Researchers have simulated attaching benzyne molecules to the outside of a nanotube to form gearteeth. Nanotubes are molecular-sized pipes made of carbon atoms. A supercomputer was used to simulate successful cooling of molecular-sized gears with helium and neon gases. To drive the gears, the computer simulated a laser that served as a motor. The laser creates an electric field around the nanotube. A positively charged atom on one side of the nanotube, and a negatively charged atom on the other side. The electric field drags the nanotube around likea shaft turning. These gears would rotate best at about 100 billion turns per second or six trillion rotations per minute (rpm). Current products of nanoscale technology include powders, films, and chemicals etc. 7


Medicine: The combination of nanotechnology and genomics (which offers the
possibility of manipulation of the DNA of humans and other species) will lead to the development of new vaccines, and treatments for genetically based illnesses. More generally in health, key applications are seen as simple and effective diagnostic sensors One of the most anticipated uses of nanotechnology is the creation of medical nanobots, made up of a few molecules and controlled by a nanocomputer or ultrasound. These nanobots will be used to manipulate other molecules, destroying cholesterol molecules in arties, destroying cancer cells or constructing nerve tissue atom by atom in order to end paralysis. Nanoscopic probes could be put in place to measure our state of health around the clock, new tools could be developed to fight genetic disease at the level of the gene, and markers could be created to detect and, one by one, destroy cancerous cells and many other.


Environment: Environmental clean up is another imagined use for nanobots, with
fingers built from nanotubes but in proportions 50,000 times as thin as human hair. These fingers would reach out and manipulate the atoms in an oil spill to render it harmless. In the energy field, atoms bonded together in a specific fashion would create a machine that converts water to hydrogen with the use of sunlight, promising a new, limitless, energy source Miniature sensors developed through nanotechnology could also be used to detect specific pollutants accidentally or deliberately released into the environment. The removal of pollutants may be achieved through filters incorporating nanoparticles, the first of which may be available within a couple of years


Before we end:

Nanotechnology vs others: By encompassing all phases of production from
chemical processing to final assembly, molecular manufacturing can be far more flexible than any other single technology, with the possible exception of programmable computers. A few other technologies may be equally dangerous, but are easier to control. Nuclear technology can only be used for a few things—bombs, power generation, cancer treatment—so it has been possible for a fairly small international effort to keep control of various aspects of this technology. Biotechnology is flexible in its domain, but biotech products have been difficult to engineer. Conventional rapid prototyping systems will improve gradually; it will be a while before they can make complete products, and even longer before they can cheaply duplicate themselves.


Risks: Nanotechnology brings with it unprecedented risks: massive job
displacement causing economic and social disruption, threats to civil liberties from ubiquitous surveillance, and the specter of devastating wars fought with far more powerful weapons of mass destruction. Availability of unregulated molecular manufacturing could create several serious problems. Criminal and terrorist activity would benefit from smaller, more capable products. Small, widely available, cheap surveillance devices would allow an unprecedented invasion of privacy by governments, criminals and neighbors Never before have we faced such a tremendous opportunity—and never before have the risks been so great. We must begin building hope to succeed in walking the narrow middle line between dispassionate observation and zealous activism; between being boosters for nanotechnology and being sentinel The variety of potential problems, in economic, military, political, humanitarian and environmental spheres, indicates that no simple solution can work.


Limitations: The main technical barriers are the:

  

Lack of a detailed design The need for a better understanding of the laboratory The main institutional barrier is a widespread belief that Nanotechnology is not worth pursuing at this time. The development of even primitive mechanochemical fabrication ability could be followed rapidly by development of an integrated, automated, selfcontained, human-scale factory. Such a sudden increase in advanced manufacturing capability could have substantial military as well as economic


advantages for the nation or bloc that controls it. This greatly increases the incentive for rapid and early development of MNT. 

Safe Development: In developing molecular manufacturing, it may be that
the safest course is a single, international development effort, leading to a technology that can be widely distributed and carefully administered—with tight technological controls in place to limit its use. This would provide an infrastructure for rapid humanitarian relief with basic products, profit making with other products, and perhaps even arms control—if nations could be restrained from developing independent, unmonitored molecular manufacturing capability. If this is in fact the best approach, the need for action is even more urgent. A nation with an entrenched development program may be less likely to join or support an international development effort. It will not be easy to convince military and political leaders, captains of industry, and environmental and social watchdogs that the best course of action involves giving up some control in order to retain some control. Development of molecular manufacturing appears inevitable for two reasons. The first is its immense value. Even if public pressure prevented it from being used in consumer goods, various militaries would not hesitate to develop it as a tremendous aid to military capabilityThe second reason is the increasing ease of development.


About us:  Chandan Kumar IInd year CSE SASTRA Deemed University Thanjavur, Tamil Nadu Reg No. 010703151 email id:  Vipul Jain IInd year CSE SASTRA Deemed University Thanjavur, Tamil Nadu Reg No. 010703145 email id:


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