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Comment: Re:oh jeez. (Score 1) 140

by MancunianMaskMan (#49385461) Attached to: World's Largest Aircraft Seeks Investors To Begin Operation

... Helium .. has roughly half of the lifting capacity of Hydrogen....

not really, the "lifting capacity" is from the difference in mass between lifting gas and surrounding air. Air is ~29 g/mol, so the ratio of lifting capacity of H2:He is

[(29 - 2) / 29] : [(29 - 4) / 29] = 27/25,

works out at 8% difference. The containment vessel's weight is typically more significant than the gas itself in a lighter-than-air craft.

Balloons with He3 give only 3% more lift than He4, lunacy!

Comment: The War of the Worlds, Ch. Two: The Falling Star (Score 1) 122

by MancunianMaskMan (#47473175) Attached to: Giant Crater Appears In Northern Siberia
An enormous hole had been made by the impact of the projectile, and the sand and gravel had been flung violently in every direction over the heath, forming heaps visible a mile and a half away. The heather was on fire eastward, and a thin blue smoke rose against the dawn. Link here (e.g.)

Comment: Re:How surprising... not (Score 2) 110

by MancunianMaskMan (#47211269) Attached to: There's No Wind Chill On Mars

Mars' atmosphere is .. around 20 mBar ..it's near-vacuum. And vacuum makes for a very good thermal insulator.

"For all practical purposes" is not correct. The thermal conductivity of a gas is near-independent of pressure down to very low pressures, until the mean free path of particles becomes large compared to the distance to the solid where the heat gets dumped. 20mBar and the MFP is still tiny.
You need a pretty good vacuum (10^-4mbar or so) in a coffee flask otherwise it doesn't change a thing.

Comment: Re:Some things stick (Score 2) 422

by MancunianMaskMan (#47106093) Attached to: Why You Shouldn't Use Spreadsheets For Important Work
Excel checks formulas for "consistency" so if you have b1 : = a1+1 , b2: =a2+1 , b3: =a42 + 1 , b4: =a4+1 , then the ropey B3 will be flagged up. Of course there are sometimes false positives and you switch this check off or ignore it, and who knows how many false negatives.
The message "just say no to Excel" still stands.

Comment: Re:preventing officers from being able to deactiva (Score 1) 152

by MancunianMaskMan (#46947439) Attached to: London Police To Wear Video Cameras In Pilot Project
the cameras a re supposed to have a 30 seconds buffer that always records, so you get the 30 seconds before you press "Start". That, and the fact that the battery is supposed to last a whole shift, makes them a very interesting device. Where can I buy one of those?

There's a whole WORLD in a mud puddle! -- Doug Clifford

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