Mark 18 nuclear bomb, also known as the SOB or Super Oralloy [1] Bomb, was the highest yield (500 Kt) unboosted pure...
Mark 18 nuclear bomb, also known as the SOB or Super Oralloy [1] Bomb, was the highest yield (500 Kt) unboosted pure fission bomb produced by the US. Noted nuclear weapon designer Ted Taylor of the Project Orion [2], etc fame was the lead designer.

George Dyson, son of Freeman Dyson of the Project Orion, etc fame in his book "Turing's Cathedral" p.214, says that Ted Taylor designed it in part to show that fusion bombs were unnecessary, because the pure fission yield ought to be enough for anyone. But there was no stopping it.

90 Mark 18's were build, but almost immediately decommissioned, obsoleted by boosted fission and true fusion bombs.

Soviet analog, allegedly, was RDS-7 (500 Kt), never fully developed because it was obsoleted by Sakharov's boosted "Layer Cake" design (Joe-4/RDS-6s, 1953)

http://en.wikipedia.org/wiki/Mark_18_nuclear_bomb
http://en.wikipedia.org/wiki/Ted_Taylor_(physicist)
http://books.google.com/books?id=9nvfmUS03c4C&pg=PP214

[1] code name for U-235

[2] https://plus.google.com/112065430692128821190/posts/bmCaULpVR16
http://en.wikipedia.org/wiki/Ted_Taylor_(physicist)

Labels: Oleg Zabluda

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When I was about 5 years old, I decided to test experimentally if the Earth really turns on its axis, as the...
When I was  about 5 years old, I decided to test experimentally if the Earth really turns on its axis, as the grownups and their books were telling me.

In this I was already way ahead of Copernicus (1473-1543), since he never attempting or proposed anything like that. In fact, people around him weren't stupid, and were telling him (since the ancients) that if the Earth was really turning, the equator would be moving at 40000/(24*3600)=0.5 km/sec, and buildings, trees and people would be flying off everywhere. His only counter was that turning round and round was their "natural motion" and other nonsense like that [1].

The subject was only settled with Galileo (1564-1642) and his original relativity theory (1632), Jean Richer's (1630–1696) pendulum experiments on the equator (1673), explained by Newton's (1642-1727) mechanics and theory of gravity (1687), verified by French Geodesic Mission (1743)
https://plus.google.com/112065430692128821190/posts/ZtNiL5AnQkL

Unconcerned with complexities and technicalities like these, I simply chose a spot behind the playground in the day care (called Kindergarten back in USSR) and put something about an inch underground. Several days later, I went to check on it, couldn't find it, and concluded that rotation of the Earth must have rotated it elsewhere. Theory thus confirmed, my trust in authority was not shaken until much later.

http://en.wikipedia.org/wiki/Jean_Richer

#sciencesunday  
http://en.wikipedia.org/wiki/Jean_Richer

Labels: Oleg Zabluda, sciencesunday

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Remember how you've been taught in elementary school that red and yellow autumn leaf colors simply appear after the...
Remember how you've been taught in elementary school that red and yellow autumn leaf colors simply appear after the degradation of chlorophyll that masked these pigments, and that they served no function. That ain't quite so.

While for yellow/orange color (Xanthophyll pigments are carotenoids, like beta-carotene) it is indeed true, it has been shown (only in 2003!) that in many plants red/purple color (Anthocyanin are phenols, like Litmus, similar to пурген [1]) is not simply unmasked but rather synthesized de novo by leaves in mid-senescence i.e. once roughly half of chlorophyll has been degraded [2].

This, naturally, leads to the question - what for? You can read the poorly written paper below, full of wild fantasies and speculations [3] why Northern Europe allegedly became dominated by yellow autumn leaves, but North American trees allegedly continued to need the bright red [4].

http://www.dailymail.co.uk/sciencetech/article-2043891/Scientists-solve-riddle-leaves-change-colour--fall-shortly-after.html

"What Do Red and Yellow Autumn Leaves Signal?" Simcha Lev-Yadun, University of Haifa, Israel
http://research.haifa.ac.il/~biology/simcha/Publications/I90.pdf

http://en.wikipedia.org/wiki/Autumn_leaf_color

[1] Anthocyanins temporarily color the edges of some of the very young leaves as they unfold from the buds in early spring. They also give the color to cranberries, red apples, blueberries, cherries, strawberries, and plums, which is part of the reason that if you eat too much тебя проносит (Phenolphthalein=пурген).

[2] The amino acids released from degradation of light harvesting complexes are stored all winter in the tree's roots, branches, stems, and trunk until next spring when they are recycled to re‑leaf the tree.

[3] Or a much better one: "Unravelling the evolution of autumn colours: an interdisciplinary approach" (2011), Archetti et.al.
http://bioserv.fiu.edu/~leed/articles/TREE-Autumn-2009.pdf

[4] Actually, compared to Western Europe, North America provides many more arbor species (more than 800 species and about 70 oaks, compared to 51 and 3 respectively in Western Europe) which adds many more different colors to the spectacle. During ice ages in North America, species were protected in more southern regions along north–south ranging mountains, which was not the case in Europe. Still evolutionary role of red color is not understood and not really studied yet.

#sciencesunday  
http://www.dailymail.co.uk/sciencetech/article-2043891/Scientists-solve-riddle-leaves-change-colour--fall-shortly-after.html

Labels: Oleg Zabluda, sciencesunday

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