mcdaniel@uicsrd.UUCP (06/12/87)
Recently, someone sent me "The US Army Materiel Command; 1984-1987;
'The Thompson Years'", which appears to be an unclassified report of
some accomplishments in research, management, et cetera. Here, I will
list some excerpts, with questions I have. I would appreciate any
answers. Quotes are set off with "=".
Foreign nationals, stop reading here! :-)
= 2-4. In 1986 photonic computers were transitioned from the
= laboratory bench to field testing.
That is the paragraph in its entirety.
Does "photonic" mean "optical"?
What is the current state of progress in optical computing?
Is there any hope for government tech writers? :-)
= 2-6. Significant promise has been demonstrated that a practical
= system can be achieved which can extract sufficient potable water
= from the engine exhaust.
"Sufficient" for what? In other words, for those who know more
chemistry than I, at most how many liters of H2O can be produced from
one liter of gasoline (or diesel fuel)? Assume no inefficiencies or
impurities like incomplete combustion or combustion with something
other than oxygen, and assume standard commercial grades of fuel
(whatever THAT is).
= 2-10. Natick has demonstrated the feasibility of developing
= calorically dense (7.1 kcal/cc), nutritional sustainment modules
= components, based on Infusion, Compression, and Extrusion
= technologies, and having high acceptance.
Translation: they've developed super granola bars that people like.
Sigh. "Dear, could you pass the Calorically Dense Nutritional
Sustainment Modules?"
= 2-12. The investigation of a novel material of potentially
= tremendous significance to ballistics has supported the hypothesis
= that a collection of triplet helium atoms could be contained and
= exploited as a medium of energy storage, the capacity of which is
= three orders of magnitude greater than those of secondary explosives.
What is a "triplet helium atom[s]"? I know that there have been
rather unstable chemical compounds made from noble gases (xenon
hexaflouride?), but they were of atoms with higher atomic weights.
= 2-15. Through an intensive in-house effort optical processing has
= been taken from the laboratory bench to a fieldable test-bed capable
= of intercepting and exploiting advanced modulation communication
= signals. An effort to develop advanced optical signal processing
= modules for utilization in "smart" responsive jammers to counter
= enemy frequency-agile (hopping) radio nets has been launched. A
= concept for a bistatic radar system which provides a real time,
= self-registered, covert surveillance capability and is inherently
= immune to anti-radiation missiles has been developed and
= demonstrated. . . . Significant advances have taken place in the
= area of acousto-optic signal processing reggedization. Several
= processors have been designed, built, tested, and in some cases
= incorporated into test-bed signal processing systems.
More on "optical processing".
What is an "advanced modulation technique"?
What is a "bistatic radar system"? I assume it is a passive system
that observes radio waves generated elsewhere.
What is "acousto-optic"?
Any reader-generated review and analysis would have high acceptance. .
. . Oh no! Infection with Mil-Speak has been established!
Ameliorization of end-user condition is indicated . . . <gag> <choke>
<arrrrrgh> . . .
--
Tim, the Bizarre and Oddly-Dressed Enchanter
Center for Supercomputing Research and Development
at the University of Illinois at Urbana-Champaign
UUCP: {ihnp4,seismo,pur-ee,convex}!uiucdcs!uicsrd!mcdaniel
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BITNET: mcdaniel@uicsrd.csrd.uiuc.eduhoward@cpocd2.UUCP (Howard A. Landman) (06/20/87)
I'm cross-posting this into sci.physics, because there are people there who are more knowledgeable than I and might be able to supply information I couldn't. Or even correct any errors in my analysis! In article <42000001@uicsrd> mcdaniel@uicsrd.CSRD.UIUC.EDU writes: >= 2-12. The investigation of a novel material of potentially >= tremendous significance to ballistics has supported the hypothesis >= that a collection of triplet helium atoms could be contained and >= exploited as a medium of energy storage, the capacity of which is >= three orders of magnitude greater than those of secondary explosives. > >What is a "triplet helium atom[s]"? I know that there have been >rather unstable chemical compounds made from noble gases (xenon >hexaflouride?), but they were of atoms with higher atomic weights. Consider a system containing two electrons (such as a helium atom). If the electron spins are opposite, the system has net spin 0 and therefore the projection of that spin on any coordinate axis can only be 0. Because there is only one possibility (for some measurements this will show up as a curve with a single peak), such a state is called "singlet". Now suppose the electron spins are parallel, so the total spin is 1. The projection of this spin onto a coordinate axis can result in spins of +1, 0, or -1, leading to a triple-peaked curve and the name "triplet". For helium, Pauli exclusion prevents the electrons from both being in the ground state (1S orbital) unless their spins are opposite. So, if "triplet helium" is referring to the electronic state, one electron would have to be excited (to at least the 2S orbital) for triplet helium to exist. Such an atom could not easily decay into the ground state for helium, because the excited electron would have to reverse spin first, so it might well be quasi-stable. If you collected a bunch of them all together with spins +1, there would be no way for them to do spin reversal solely by interaction with each other because spin is conserved (if one goes down to 0, the other must go up to +2!). So the only source of spin reversal (leading to energy release as the electron drops from 2S to 1S) is through interaction with something else (walls of container, magnetic field, ...). Long term storage might be very tricky. How much energy could triplet helium store? Well, I wasn't able to find a reference to the energy of the first excited state, but it is bounded from above by the ionization energy of 24.6 eV. The difference between ground state and first excited state should be a fair fraction of that; let's assume about 10 eV or so. Now 10 eV/atom = 1.6 x 10^-18 J/atom = 10^6 J/mole = 2.5 x 10^8 J/Kg. 250,000,000 Joules per kilogram, not bad. Here's how such stuff might be made, using a setup similar to the classical Stern-Gerlach experiment: +1 helium (captured + stored) / excited strong / helium------>magnetic-- 0 helium (recycled to exciter) atoms field \ \ -1 helium (captured + stored) Notice from this that you'll be generating equal amounts of +1 and -1 spin helium triplets, and that all you have to do is mix them together to balance the spins and allow energy release. Helium atoms are also pretty light, so the muzzle velocity could be impressive. A remoter possibility is that they're talking about a triplet state in the helium nucleus. Similar considerations would hold, but the energy levels would be different. It is also possible to have triplets due to nuclear spin in biatomic molecules such as O2. Such "triplet oxygen" has the nuclear spins of both oxygen atoms parallel. I don't think it's possible to store much energy in such triplets. Q:"Dr. Pauli, where did you get your exclusion principle?" A:"I made it up!" Howard A. Landman ...!{oliveb,...}!intelca!mipos3!cpocd2!howard howard%cpocd2%sc.intel.com@RELAY.CS.NET