Published on Mar 02, 2016
Nanomachines are machines of dimensions in the range of nanometers. They include micro scale replicas of present day machines like the nanogears,nanoarms or the nanorobots as well as futuristic machines which have no present day analogs, like the assembler which can assemble atoms to produce further machines or assembler themselves.
Though there can be analogous of today's mechanical components, the way in which both these categories are manufactured will be entirely in contrast to each other with regard to what we an call as the direction of manufacturing While today's machines are manufactured by the top-bottom approach in which they are machined down from larger components or bulk of the component materials , nanomachines will be manufactured by the bottom-top approach where they are built atom by atom, placing the individual atoms precisely at the required positions.
No nanomachines in the true sense have yet been manufactured, although feasibility of producing several of them is confirmed by various means. The main difficulty lies in the inability of today's handling facilities to account for manipulating such sub atomic particles. Producing them by means of chemical reactions is the most apt one for controlling atomic positions. Scientists have been able to obtain virtual machines by means of computer simulated chemical reactions and this proves their feasibility. The distance from actually making them will be bridged by finding way to control and predict the outcome of chemical reactions more quickly and precisely.
Synthesis Of Nanomachines
The present generation micromachines which fall in the category of nanomachnes in the sense that they are made by molecular technology are currently synthesized by means of chemical reactions. As of now, chemical synthesis is conducted almost exclusively in solution, where reagent molecules move by diffusion and encounter one another in random positions and orientations.
The prominent synthesizing techniques can be classified as follows-
• Solution-phase synthesis
• Enzymatic synthesis
Solution-phase synthesis poses familiar problems of reaction specificity. Although many small-molecule reactions proceed cleanly and have high yields, large molecules with many functional groups present multiple potential reaction sites and hence, can be converted into multiple products.
Although a spectrum of intermediate cases can be identified, enzymatic synthesis differs significantly from the standard solution-phase model. Enzymatic reactions begin with reagent binding, which places molecules in well-controlled positions and orientations. The resulting high effective concentrations resulting high reaction rates.
Mechanosynthesis differs from enzymatic catalysis, yet many of the same principles apply. One can perform mechanosynthesis by using macroscopic devices, such as scanning tunneling and atomic force microscope (STM and AFM) mechanisms. The first clear example of a mechanically controlled synthesis was the arrangement of 35 Xenon atoms on a nickel crystal to spell 'IBM'.
Biosynthesis involves synthesize of biological materials.
ASSEMBLER NANOMACHINES AND THEIR POSSIBLE IMPACT ON SOCIO-ENVIORNMENTAL FACTORS
If scientists manage to build nanomachines that can rearrange atoms, the assemblers, a world of exciting possibilities will open up. Purpose designed nanomachines could be used to provide breakthrough treatments for many diseases. Medical nnaomachines programmed to recognize and disassemble cancerous cells should be injected into the blood stream of cancer suffers, thus providing a quick and effective treatment for all types of cancer. Nanomachines would be used to repair damaged tissues and bones. They could even be used to strengthen bones and muscle tissue by building molecular support structures by reassembling nearby tissue. With the ability to manipulate human cells at the atomic level, medical science will rapidly devise treatments for most human illness. And since nanomachines will be designed to make copies of them, these treatments will be inexpensive and available to the entire population.
Food shortage and starvation will be a thing of the past if nanotechnology is perfected. Nanomachines will be able to turn any material into food, and this food could be used to feel millions of people world wide. Again, since the technology is self replicating, food produced by nanomachines will be low cost and available to all.
As well as food, nanomachines will be able to build other items to satisfy the demands of our growing population of consumers. Clothing, houses, cars, television and computers will be readily available at virtually no cost. Furthermore, there will be no concern about the garbage produced by the new consumerist society because nanomachines will convert it all back into new consumable goods.
Environmental problems such as ozone depletion and global warming could be solved with nanotechnology. Swarms of nanomachines would be released into the upper atmosphere. Once there, they could systematically destroy the ozone depleting chlorofluorocarbons (CFCs) and built new ozone molecules out of water and carbon dioxide. Ozone is built out of 3 oxygen atoms, and since water and carbon dioxide both contain oxygen, the atmosphere contains a plentiful supply of oxygen atoms. While the ozone construction teams are at work in the upper atmosphere, teams of specialized nanomachines would be employed to destroy the excess carbon dioxide in the lower atmosphere. Carbon dioxide is a heat trapping gas, which has been identified as one of the major contributors to global warming. Removing excess carbon dioxide could help halt global warming and bring the planet’s ecosystem back into balance. This will benefit all species on Earth.
The perfection of nanotechnology and the production of nanomachines would herald a new age for humanity. Starvation, illness and environmental problems could quickly come to an end. But how realistic are the goals of nanotechnology? Will it ever be possible to produce machines the size of atoms? And if so, how feasible is it to build nanomachines that can build copies of themselves? Before we get carried away the promises of nanotechnology, we should take a look at some of the problems that are yet to be solved.
HURDLES AND CHALLENGES
An important challenge to overcome is one of engineering. How can we physically build machines out of atoms? Rearranging atoms into new shapes is essentially building new molecules and this is no easy task. Using contemporary technology to rearrange atoms has been said to be analogous to assembling LEGO blocks while wearing boxing gloves. It is virtually impossible to snap individual atoms together. All we can do is crudely push large piles of them together and hope for the best. Scientists hope that once this initial challenge is overcome, nanomachines will usher in a new age of molecular engineering and previous problems will be a thing of the past. The new machine will allow scientists to take off the boxing gloves and accurately snap together individual atoms to build virtually any molecule.
This is nice in principle, but the question of how to build the first nanomachines remains. Nanotechnology thinks that it will be impossible to build the first nanomachine by using large-scale equipment. Although progress is being made in the miniaturization of integrated circuits and in the ultra-fine finishing of high quality optical components, the large-scale technology being used doesn’t let us take off the boxing gloves. There is a limit to how far down these machines can go. Super smooth lens polishing is one thing, but moving individual atoms is something else all together. Nanotechnology need to get the boxing gloves of f before they can build the first nanomachines.
One way to work without boxing gloves is to patiently experiment wit chemical synthesis. The idea is to build molecules of increasing complexity by allowing atoms to assemble to rearrange in natural ways. When molecules are mixed, they naturally form new molecules. Through extensive experimentation, more control can be gained over how molecules are formed. In time, it is conceivable them chemists will be able to position individual atoms using a range of techniques developed in chemical synthesis. Chemical synthesis is promising. In computer simulations, molecularly stable gears and cogs have been formed through chemical synthesis.
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