[tt] advanced nanotechnology - 2 new articles
Eugen Leitl
<eugen at leitl.org> on
Thu Jul 12 12:05:17 UTC 2007
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Date: Thu, 12 Jul 2007 07:27:10 -0400
To: eugen <eugen at leitl.org>
Subject: advanced nanotechnology - 2 new articles
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"[2]advanced nanotechnology" - 2 new articles
1. [3]Nanotechnology enhanced domed cities versus nuclear weapons
2. [4]India has a home grown nuclear fission Thorium reactor design
3. [5]More Recent Articles
[6]Nanotechnology enhanced domed cities versus nuclear weapons
I will explore how a series of [7]dome shells over cities could be
made with molecularly precise materials that would be resistant to
nuclear weapons.
Note: This is only a speculative thought experiment. Even if you had
the required nanotechnology, making the defense system would be a
wasteful and provocative act. The economic abundance that can be
provided by nanotechnology can be used to remove the motivations and
needs for conflicts and arms race competitions. Although I will
describe a partially successful defense against some nuclear weapons,
a foe that has nukes and decent nanotechnology could defeat this. Plus
just building a lot of nukes and firing a sequenced multiple shot
would penetrate and damage the protective domes and overwhelm the
protection.
[8]del.icio.us
[778194603_44e81eba19.jpg?v=0]
One mile wide Buckminster Fuller proposed dome
Buckminster Fuller appears to have made the first specific proposal
in 1965. Claiming that the geodesic dome had no practical limit on
its size, he described a glass-panelled dome 3 km in diameter and
1.6 km tall spanning a portion of Manhattan Island; he claimed that
it would reduce air pollution and provide comfortable weather all
year. The dome would not fully enclose the area beneath it, as with
most fictional domes, but would float on air at roughly the height
of a contemporary skyscraper
The goal of the largest outer dome would be to resist unexploded
nuclear devices from penetrating without being forced to explode. Then
the hardened inner shells would resist the resulting nuclear blasts.
So in this case the outer shells would fully enclose the city. They
could have large panels that are open during times of peace.
An active outer shell with [9]reactive armor or electric reactive
armor.
The largest domes that have already been constructed:
The largest mast supported dome is the [10]Millenium dome which is 365
meters in diameter.
[11]Largest concrete reinforced dome 71 meters
[12]Geodesic domes have been made 216 meters in size
Nanotechnology can make materials one hundred times stronger than
ordinary concrete and rebar. Molecular manufacturing could make large
dome shells of stronger materials.
How strong can the nanotech materials be?
Buried structures in the 1960s were made with 55psi. ICBM silos
apparently had 2000psi. Command bunkers maybe 4000psi They were able
to survive near hits within a few hundred meters.
Materials with higher compressive strength would help make a dome
tougher.
On [13]wikipedia discusses superconcrete
Several blocks of concretes were demonstrated with abnormally high
compressive strengths between 50,000 and 60,000 PSI at 28 days. The
blocks appeared to use an aggregate of steel fibres and quartz -- a
mineral with a compressive strength of 160,000 PSI, much higher
than typical high-strength aggregates such as granite
(15,000-20,000 PSI).
Compressive strength additives with 160,000 PSI is about 1.1 GPa.
[14]Boron carbide has a compressive strength of 440,000 psi Almost
three times the strength of the reinforcing material in superconcrete.
The ultimate compressive strength of c-BN (cubic boron nitride) is
between 4.15 and 5.33 gpa. So about 4 times better than steel fibres
and quartz.
[15]Diamond is still almost twice as good as cubic boron nitride and 8
to 10 times better than quartz. Mature molecular manufacturing and
nanotechnology can use diamond as a building material.
This site had an article that discussed how [16]Monolithic Domes that
are buried up to 30 feet deep are able to withstand pressures up to 1
ton per square foot (2000 psf). This is 13 psi with relatively
ordinary concrete and rebar (special concrete can be 15 to 20 times
better now and diamond and nanomaterials about 150 times). The diamond
and nanomaterial dome would be city sized and have an overall strength
of about 2000 psi.
Nuclear weapons overpressure
[17]An online nuclear blast calculator
For a one megaton bomb
15 psi: 2.46 km
5 psi: 4.52 km
2 psi: 7.92 km
1 psi: 11.67 km
[nuclearblastpg.jpg]
One megaton blast radii
It seems to be about pi (3.1416) times the overpressure for half the
distance closer
PSI meters away
47 1230
148 615
465 307.5
1461 153.8
4590 76.9
The outer shell would just need to resist penetration by an unexploded
nuke missile and force it to detonate.
The next shell (a monolithic dome with say 1300psi) would 200 meters
farther in would then be able to resist the blast.
[800px-Castle_Bravo_Blast.jpg]
Big nuclear explosion. Castle Bravo Blast
50 megatons
15 psi: 9.07 km
5 psi: 16.66 km
2 psi: 29.16 km
1 psi: 42.98 km
PSI Meters from ground zero
47 4535
148 2267.5
465 1134
1461 567
4590 283
Another shell 600 meters smaller than outside radius of largest shell
to resist a 50 megaton blast.
If the outer shell is a geodesic dome, then when pieces are knocked
out then other pieces could be ready to be moved quickly back into
place to regenerate the protection.
There would be other active defences to try and shoot down missiles
and attacks.
FURTHER READING:
Here is a chapter from an online reference on [18]high performance
concrete with formulas.
[19]nuclear bomb effects calculations
o [20]Email to a friend o [21]Search o
[22]Rate 'Nanotechnology enhanced domed cities versus nuclear weapons'
[23]India has a home grown nuclear fission Thorium reactor design
[24]A novel Fast Thorium Breeder Reactor (FTBR) being developed by V.
Jagannathan and his team at the Bhabha Atomic Research Centre (BARC)
in Mumbai has received global attention after a paper was submitted to
the International Conference on Emerging Nuclear Energy Systems
(ICENES) held June 9-14 in Istanbul.
They believe their FTBR is one such 'candidate' reactor that can
produce energy from these two fertile materials with some help from
fissile plutonium as a 'seed' to start the fire.
By using a judicious mix of 'seed' plutonium and fertile zones
inside the core, the scientists show theoretically that their
design can breed not one but two nuclear fuels - U-233 from thorium
and plutonium from depleted uranium - within the same reactor.
This totally novel concept of fertile-to-fissile conversion has
prompted its designers to christen their baby the Fast 'Twin'
Breeder Reactor.
Their calculations show the sodium-cooled FTBR, while consuming
10.96 tonnes of plutonium to generate 1,000 MW of power, breeds
11.44 tonnes of plutonium and 0.88 tonnes of U-233 in a cycle
length of two years.
'At present, there are no internal fertile blankets or fissile
breeding zones in power reactors operating in the world,' the paper
claims.
The concept has won praise from nuclear experts elsewhere. 'Core
heterogeneity is the best way to help high conversion,' says Alexis
Nuttin, a French nuclear scientist at the LPSC Reactor Physics
Group in Grenoble.
Thorium-based fuels and fuel cycles have been used in the past and
are being developed in a few countries but are yet to be
commercialised.
France is also studying a concept of 'molten salt reactor' where
the fuel is in liquid form, while the US is considering a
gas-cooled reactor using thorium. McLean, Virginia-based Thorium
Power Ltd of the US, has been working with nuclear engineers and
scientists of the Kurchatov Institute in Moscow for over a decade
to develop designs that can be commercialised.
India does not have sufficient uranium to build enough thermal
reactors to produce the plutonium needed for more FBRs of the
Kalpakkam type.
'Jagannathan's design is one way of utilising thorium and
circumventing the delays in building plutonium-based FBRs,' says
former BARC director P.K. Iyengar.
o [25]Email to a friend o [26]Search o
[27]Rate 'India has a home grown nuclear fission Thorium reactor
design'
More Recent Articles
* [28]Monolithic Domes for military, space and polar regions
* [29]California population projected at 60 million in 2050
* [30]Software and power key to supercomputers beyond petaflop
* [31]Air pollution index that is tied to health risk
* [32]DNA synthesis costs and projections
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References
1. http://www.feedblitz.com/
2. http://advancednano.blogspot.com/
3. file://localhost/tmp/mutt.html#64651_0
4. file://localhost/tmp/mutt.html#64651_1
5. file://localhost/tmp/mutt.html#64651_recap
6. http://advancednano.blogspot.com/2007/07/nanotechnology-enhanced-domed-cities.html
7. http://en.wikipedia.org/wiki/Domed_city
8. http://del.icio.us/post?url=http://advancednano.blogspot.com/2007/07/nanotechnology-enhanced-domed-cities.html&title=Nanotechnology%20enhanced%20domed%20cities%20versus%20nuclear%20weapons
9. http://en.wikipedia.org/wiki/Reactive_armour
10. http://en.wikipedia.org/wiki/Millennium_Dome
11. http://en.wikipedia.org/wiki/List_of_world%27s_largest_domes<br>
12. http://en.wikipedia.org/wiki/Geodesic_dome
13. http://en.wikipedia.org/wiki/Concrete#Strength
14. http://www.electroabrasives.com/prod_b4c.php
15. http://www.custodiam-china.com/en/diam_en.htm
16. http://advancednano.blogspot.com/2007/07/monolithic-domes.html
17. http://meyerweb.com/eric/tools/gmap/hydesim.html?ll=-73.9971,40.7223&yd=100
18. http://www.tfhrc.gov/structur/hpc/hpc2/chap4.htm
19. http://www.princeton.edu/~globsec/publications/effects/effects.shtml
20. http://www.feedblitz.com/f/f.fbz?Fwd2FriendEdit=64651;456516;http://advancednano.blogspot.com/2007/07/nanotechnology-enhanced-domed-cities.html;Nanotechnology%20enhanced%20domed%20cities%20versus%20nuclear%20weapons;71706
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22. LYNXIMGMAP:file://localhost/tmp/mutt.html#outbrainMap_64651_0
23. http://advancednano.blogspot.com/2007/07/india-has-home-grown-nuclear-fission.html
24. http://www.indiaenews.com/technology/20070701/58545.htm
25. http://www.feedblitz.com/f/f.fbz?Fwd2FriendEdit=64651;456516;http://advancednano.blogspot.com/2007/07/india-has-home-grown-nuclear-fission.html;India%20has%20a%20home%20grown%20nuclear%20fission%20Thorium%20reactor%20design;71706
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27. LYNXIMGMAP:file://localhost/tmp/mutt.html#outbrainMap_64651_1
28. http://advancednano.blogspot.com/2007/07/monolithic-domes.html
29. http://advancednano.blogspot.com/2007/07/california-population-projected-at-60.html
30. http://advancednano.blogspot.com/2007/07/software-and-power-key-to.html
31. http://advancednano.blogspot.com/2007/07/air-pollution-index-that-is-tied-to.html
32. http://advancednano.blogspot.com/2007/07/dna-synthesis-costs-and-projections.html
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