NANOTECHNOLOGY AN OVERVIEW
NANOTECHNOLOGY â€œ AN OVER VIEW
Nanotechnology is often termed as a system innovation, implying that it is expected to initiate an increase in number of innovative developments in various sectors of technology, various social areas of applications and economic sectors.
SUBMITTED BY: 1.SUKRUTHI.S.R.
VII Sem Dept of Industrial and Production Engineering
P.E.S. COLLEGE OF ENGINEERING
One of the biggest scientific trends of the 21st century has been centered on something incredibly small: nanotechnology. But what is nanotechnology? That is the most difficult question to answer, even though itâ„¢s all over the news these days. The crux of the problem is that it is beyond the understanding of most people. Unless we have studied it extensively in university (and even then the picture isnâ„¢t necessarily complete) we wonâ„¢t know what a quantum dot is. We will need to know the underlying science that drives it, the tools we use to apply it, and the potential benefits and dangers of it.
Nanotechnology is a broad term for the application of scientific understanding towards fabricating devices and materials at the nanometer scale. Nanotechnology takes its name from a unit called nanometer-NM, which means itâ„¢s the one billionth of a meter. [1nm = nanometer (1,000,000,000 nm per m, or 10-9 m)].
Nanotechnology is primarily characterized by its overall dimension: the Nano-world. The Nano-world exists at the level of single molecules and atoms-the size of a millionth of a millimeter. Nanotechnology involves building sophisticated products from the molecular scale. As the molecule is the smallest particle of matter that exists independently, it cannot be ruled by any of us, but the technologists have started ruling the same understanding the molecular world as a tough process. This kind of molecular manufacturing will in fact result in high quality, smart and intelligent products that are 100% efficient, produced at low cost with little environmental impact.
Nanotechnology is expected to have an enormous potential for innovation because it may create effects which have not yet been feasible with any other technologies. The far reaching possibilities of nanotechnology development, which are
currently being assessed according to feasibility, find their echo in partly extreme judgments of the technology.
The specific characteristics of this dimension are that nano-particles show a completely different behavior to their larger, coarser pendants. The relatively big specific surface of nano-particles usually leads to an increase in their chemical reactivity and catalytic activity. The relatively small amount of atoms within nano-particles offsets the quasi-continuous solid state of the particle, leading to new, deviating, optical, electrical and magnetic features. From these basic features and characteristics of nano-technology, a number of possible positive and problematic (negative) effects can be derived.
Characterization of Nanotechnology:
To know about the impact of a technology, we require a familiarity with three basic elements. Viz.,
1. An Agent (the technology, substance etc whose possible effects are to assessed);
2. An impact model (a scientifically verifiable theory on how the agent acts on a potential target)
3. A target entity upon which the agent acts.
One of the basic principles of nanotechnology is positional control. At the molecular scale, the idea of holding and positioning molecules is new. Before discussing the advantages of positional control at the molecular scale, it is helpful to look at the property of self-assembly of molecules. A basic principle in self-assembly is selective stickiness i.e., if two molecular parts have complementary shapes and charge patterns-(one part has a hollow where the other part has a bump, and one part has a positive charge where the other part has the negative charge). Then they will tend to stick together in one particular way. This bigger part can combine in the same way with other parts, letting us build a complex whole from molecular pieces.
While self-assembly is a path to nanotechnology, by itself it would be hard pressed to make the very wide range of products promised by nanotechnology. For ex: we donâ„¢t know how to self assemble shatterproof diamond without using positional control through nanotechnology. During self-assembly, the parts bounce around and
bump into each other in all kinds of ways, and if they stick together when we donâ„¢t want them to stick together, we will get unwanted globs of random parts. Many types of parts have this problem. So self-assembly wonâ„¢t work for them. To make diamond, it seems as though we need to use in-discriminatory sticky parts (radicals, carbines and the like). These parts cannot be allowed to randomly bump into each other (or much of anything else, for that matter) because they would stick together when we didnâ„¢t want them to stick together and form messy blobs instead of precise molecular machines.
We can avoid this problem if we can hold and position the parts. Even though the molecular parts that are used to make diamond are both in-discriminatory and very sticky (more technically, the barriers to bond formation are low and the resulting covalent bonds are quite strong), if we can position them, we can prevent them from bumping into each other in the wrong way. When two sticky parts do come into contact with each other, they will do so in the right orientation because we are holding them in right orientation. In short, positional control at the molecular scale should let us make things which would be difficult or impossible to make without it. Given our macroscopic intuition, this should not be surprising. If we could not use our hands to hold and position parts, we must develop the molecular equivalent of arms and hands.
Life Cycle Assessment (LCA) for evaluation of nanotechnology application:
Following on from the characterization of nanotechnology and the hitherto existing production methods, we have to next identify the sustainability effects by process monitoring and evaluation of specific examples of nanotechnology applications. The most advanced and standardized procedure for evaluating environmental aspects associated with a product and predicting the product specific environmental impact is the method of life cycle analysis (LCA) which should consist of the following stages:
1. Establishing the objectives and the scope of the assessment.
2. Life cycle inventory.
3. Appraisal of impact.
4. Overall evaluation.
Following is the flowchart which clearly illustrates interdependence of these stages.
The arrows between the individual stages highlight the interactive nature of the procedure with the outcome of a given step always being fed back into the preceding stage and resulting, if necessary, in the repetition of the procedure. The LCA approach also includes methodological deficits: for some of the impact categories there exists no commonly accepted impact model.
Broad Application of Nanotechnology:
Wide areas of application of nanotechnology are found in every field and some of them are mentioned as under:
Industry & Production of goods
Stain resistant and wrinkle free fabrics
Amusement and toys
Nano-medicine and many more..
We will look into the aspects of application in nanotechnology in industry & production of goods for the present:-
Application in Industry & Production of Goods:
Molecular manufacturing is the basis of nanotechnology which will lead to production of smart, reliable and intelligent products. With nanotechnology, industrialists plan to bring thorough control of the structure of matter, and hence will be able to build objects atom by atom specifications. Nanotechnology will hence make possibly a huge range of new products. The products that are available in the market today are not 100% efficient and are worn off when handed roughly. But with the introduction of nanotechnology, we can have better and reliable products because better quality can be achieved by molecular manufacturing. By building things with atom by atom control, flaws can be made rare and non-existent. Nanotechnology will also result in inexpensive production or production cost will be considerably reduced.
Following are few examples of application of nanotechnology in production of goods:
1. Application in Automotive & Transportation Industry:
Micro and Nanotechnologies have already made an impact in the automotive and transportation industry.
In Automobiles,1. Micro chips regulate engines;
2. New technologies control car and truck braking, and
3. Electronic tuning ensures cleaner engine burn.
The automobile is one platform that is beginning to take advantage of nano-composites in diverse components and systems ranging from catalytic converters that more efficiently convert combustion by-products to benign emissions, to economical light weight plastics and coatings that enhance fuel efficiency and vehicle durability.
2. Application in Food-Sector:
Nanotechnology also has applications in the food sector. Many vitamins and their precursors, such as carotinoids, are insoluble in water. However, when skillfully produced and formulated as nano-particles, these substances can easily be mixed with cold water, and their bioavailability in the human body also increases. Many lemonades and fruit juices contain these specially formulated additives, which often also provide an attractive color.
3. Application in Cosmetic â€œSector:
In the cosmetics sector, BASF has for several years been among the leading suppliers of UV absorbers based on nano-particulate zinc oxide. Incorporated in sun creams, the small particles filter the high-energy radiation out of sunlight. Because of their tiny size, they remain invisible to the naked eye and so the cream is transparent on the skin.
A Future based on Reflection and Responsibility:
As nanotechnology continues to develop, it is likely that the debate over regulation will develop as well. Experience with recombinant DNA indicates that early concerns about safety are likely to be overblown, and that an effective regulatory regime can be based on a combination of consensus and self-regulation. Though there are likely to be some calls for a complete ban on nanotechnology, such a ban is certain to fail, and itâ„¢s unworkability means that such calls will probably come mostly from anti-technology groups that command little political support. Similarly, efforts to limit nanotechnology to military applications are likely to face technical and political hurdles as knowledge diffuses and the public seeks access to potentially life-saving technologies.
More responsible calls for regulation as well can be met through an approach that will not stifle the development of nanotechnology. Sound knowledge, calm reflection, and an aversion to media hysteria will be key requirements of those dealing with a new and highly technical subject with endless implications.
1. Non-volatile memory from nano-particles:
Researchers from University of California at Los Angeles and ROHM and Haas Electronic material company have devised a potentially low cost, high speed nonvolatile memory from polystyrene and gold nano-particles. This retains information when it is not powered. The memory can be easily manufactured from an inexpensive material making it potentially much cheaper than todayâ„¢s flash memory chips. It can be read to and written electronically, making it potentially much faster than todayâ„¢s CD and DVDâ„¢s. According to researchers, layers of the film can be stacked making it possible to store even more information in a given area.
2. Boeing Developing Nanotechnologies for New Aircraft:
The Chicago Sun Times has reported that Boeingâ„¢s Phantom Works, is developing new materials using nanotechnology. The Company is also developing new materials for use in building lighter but stronger aircraft, specialized coatings-that means, planes do not need to be repainted. They are also planning to develop lighter, smaller, more powerful and longer-lasting batteries for satellites.
Therefore, nanotechnology surely promises a brighter future and it will also help produce environment friendly products. Nanotechnology will mean greater control of matter making it easy to avoid pollution. Sophisticated products could even be made from biodegradable materials. Hence, nanotechnology will make it easy to attack the causes of pollution at technical level.
Electronics Today-July 2005.
Engineering Competition Today-December 2002.
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