X-Message-Number: 20950
Date: Thu, 23 Jan 2003 12:37:57 +0100
From: Henri Kluytmans <>
Subject: Nano and respirocytes

Yvan Bozzonetti wrote :

>Let see if I have understood something about "respirocytes": They are 
>micrometer sized spherical diamond tanks able to store gazeous oxygen at
high 
>pressure with the help of a centrifugal pump using a 10 nanometer rotor...

It does not use a "centrifugal pump" but a "Molecular Sorting Rotor". 
It does not seperate molecules by using centripal acceleration, but 
it rotates relatively slowly and it uses binding site "pockets" 
(along the rim) to seperate molecules (by Van der Waals force).

>First, why diamond? graphite sheet are nearly as strong and there is a well 
>established technology to make them in the bulk.

Nope, a graphite sheet is only one layer of atoms thick, a diamond 
wall can be made as thick as you want, and can thus be made much 
stronger. (In this case about 10nm thick.).

See paragraph 3.6 :

"Each storage tank is constructed of diamondoid honeycomb or a geodesic
grid skeletal framework for maximum strength. Thick diamond bulkheads
separate internal tankage volumes. Available structural mass is equivalent
to a 10-nm thick (~60 carbon atoms) 2.2 micron x 2.2 micron diamond sheet,
enough material for 1000 compartments ~(40 nm)3 in size for all tanks.
Compartment walls are perforated with sufficient holes of varying sizes to
allow gas to flow easily between them, with larger compartments nearest the
rotors graduating to smaller compartments more distant from the rotors to
encourage isobaric entrainment."

>Second, What is a submicrometer gas? At that scale, surface effects are 
>dominant. 

Surface effects are not dominant, but they are not negligible either. 
(The compartments are of 40 nm size.) But I guess, surface effects will 
only lower the effective pressure, so they should even lessen the strength
requirements. 

>What about using capillarity to load a cylindrical bottle made from 
>a nanotube?

And how is the capillarity going to be attached to the bottle? 
How is the device controlled ? The pressure can not be made as 
high, so this kind of device has a much lower capacity. (Maybe 
even less than a standard red blood cell.) Furthermore you would 
need real MNT anyway, even to make a device like this work.

>It seems that has been done for hydrogen, why to build atom by a atom a 
>diamond structure? Diamond or not, carbon and high pressure oxygen are a 
>noxious mix. 

Didn't you read : O2 and CO2 are stored in seperate tanks.

>Do you really would try to make such a complex, unstable, costly 
>thing 

Yes, because they will not be costly to fabricate using real MNT !
( Using reproducing systems, exponentional production and 
convergent assembly systems.)

And it will not be unstable : in the design an extremely 
conservative 100-fold structural safety margin is used.

Maybe I should add : All conservative approaches do not assume that 
self-reproducing nano-systems will be used inside de body, they 
assume that fabrication of biological repair or enhancement systems 
will take place outside the body.

>when fixing an ahemoglobin molecule to a carbon nanotube would do the 
>same work at some $/kg?

The artificial respirocyte would be several hundreds of times 
more efficient per unit volume than natural red blood cells...

I guess you didn't read the complete article (or you didnt 
understand it?).

Next time do not read the abstract only. And if you want to 
criticize the fundamental basics of MNT, read "Nanosystems" 
first and then focus your critic on assumptions and 
derivations in this book.


Cheers,
>Hkl

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