Defining Nanotechnology
from the it's-about-time dept.
SteveLenhert at nanotech.about.com writes "Encyclopedia Nanotech is an attempt to minimize confusion resulting from interdisciplinary terminology. Recently I redefined assembler the way I understand the concept and introduced two specific types of assemblers – self-assembler and directed assembler. I'm also trying to clarify the concepts of self-replication and self-assembly. I welcome any suggested definitions of words relating to nanotechnology – in particular, the word nanotechnology itself!"
June 4th, 2001 at 9:05 AM
Defintion of "nanotechnology"
Norio Taniguchi of Tokyo science University first defined nanotechnology in 1974 (N. Taniguchi, "On the Basic Concept of 'NanoTechnology'," Proc. Intl. Conf. Prod. Eng. Tokyo, Part II, Japan Society of Precision Engineering, 1974). IMHO, his definition, (given below, with unique grammar and spelling reproduced as well as possible) stands the test of time, and any further definition is mere window dressing:
'Nano-technology' is the production technology to get the extra high accuracy and ultra fine dimensions, i.e. the preciseness and fineness on the order of 1 nm (nanometer), 10(superscript)-9 meter in length. The name of 'Nano-technology' originates from this nanometer. In the processing of materials, the smallest bit size of stock removal, accretion or flow of materials is probably of one atom or one molecule namely 0.1~0.2 nm in length. Therefore, the expected limit size of fineness would be of the order of 1 nm. Accordingly, 'Nano-technology' mainly consists of the processing of separation, consolidation and deformation of materials by one atom or one molecule. Needless to say, the measurement and controll techniques to measure the preciseness and fineness of 1 nm play a very important role in this technology.
In the present paper, the basic concept of 'Nano-technology in materials processing is discussed on the basis of microscopic behaviour of materials and as a result the ion sputter-machining is introduced as the most promissing process for the technology.
June 5th, 2001 at 12:32 PM
The definitions need work
Assembler:
Self-Assembly:
It would be nice to have a definition based on "classical" thermodynamics. The reason that things can self assemble is that the lower energy state has fewer degrees of freedom and there are energy barriers to creating a "disordered" state from a self-assembled state.
Directed Assembler:
Both self-assembly and directed-assembly are going to require energy. Creating any "ordered state" from a "disordered state" (driving matter against the laws of thermodynamics) has to consume energy (though the source may be "hidden" in the feedstocks). I think the primary difference between "self-assembly" and "directed-assembly" is that in self-assembly the heat energy of the environment produces the molecular motions that allow the assembly process to occur (e.g. you can't do much self-assembly near absolute zero), while with "directed-assembly" instructions must be issued by a "controller" to take a specific molecule and put it in a specific location. Directed assembly "should" be faster than, and in theory more efficient than "self-assembly" because the molecules do not have to do a "Drunkard's Walk" to their final destination.
Coupling: from Nov. 26, 2000
"… known as actomyosin complexes couple energy from ATP into mechanical mostion with nearly 100% thermodynamic efficiency"
I believe it is incorrect to talk about thermodynamic efficiency in this context. What you want to discuss is the efficiency transfering the chemical energy in ATP bonds (released from the conversion of ATP to ADP or AMP) to mechanical work. I do not believe this is close to 100% and therefore a reference should be cited!
"… the nanoscale heat engine is able to efficiently couple the energy stored in an ATP molecule to the formation of a local temperature near absolute zero."
Huh? If temperature is measured by the absolute motion of molecules, then the enzymes that harvest the energy from ATP are never operating near absolute zero, in fact if they had a temperature near absolute zero they would cease to function. Biological enzymes function precisely because molecular motions driven by the energy of the environonment drive molecules into and out of the enzymes and because the temperatures "flex" the enzymes to bring ligands into proper alignment with each other.
IMO, the definitions need a lot of work. They should be tied very closely to underlying physical laws where appropriate. The abstracted definitions should cite these laws so people who really understand these concepts can see how the definitions are derived and the serious scientists don't end up discounting the "layperson's" definitions.
June 6th, 2001 at 12:54 PM
Coinage of "nanotechnology"
Taniguchi's paper was the first known published use of the hyphenated form "nano-technology" but Eric Drexler's apparently independent coinage of the term "nanotechnology" in his 1986 book Engines of Creation was, I think, seminal to the current widespread usage, although one might argue that the derivation from "microtechnology" was too obvious for anyone to claim specific coinage.
June 6th, 2001 at 12:58 PM
And while we're at it…
I myself have advanced a new concept, the self-promoting nanofactassemblerizer, which is kind of like an expert in nanotechnology, but better, becasue he doesn't need any specific knowledge or credentials.
June 9th, 2001 at 5:15 AM
Re:The definitions need work
Thank you very much for the feedback. To address your points about my revolutionary definition of assembler :
As far as defining "self-assembly" and "directed assembly" (and their corresponding assemblers), I'm not sure what you mean by "classical" thermodynamics. Self-assembly is clearly driven by the fact that starting state is of higher energy (or order) than the final state – thus energy would be released during the assembly process. To clear up possible confusion, I added "…with an energy difference between the starting and finnished state being the driving force." to the definition of self-assembly. What seems to be missing now is a definition of "order" – have you got one?
Regarding the coupling article – one of the links was broken – went to the wrong page! Hence, I apologize for any confusion. I fixed it, so if you click on the rmo dynamic efficiency it goes to the reference, which should be BioSystems (1999) 51, 15-19. In this case, temperature is measured by absolute motion of atoms (not molecules), and the theory is that energy from ATP is used to pump heat out of a cooled region – to create a heat engine in which the heat returning to the cooled region is the driving force for the mechanical motion. Do you disagree with the model presented in that paper – and the conclusions regarding the efficiency?
Overall, I appreciate the feedback – and want more!
November 1st, 2004 at 5:19 AM
Re:Defintion of "nanotechnology"
Has anybody a copy of the original article? It is widely referred to but I never saw the article and could not find it on the web.