Houthi

An interesting article on the recent history and the players. I won't swear to it's completeness, of course -- I'm nowhere near knowledgeable about Yemen.

Stairs in an emergency

Some 911 survivors described getting out of the 60+'th floor by going down the tower stairs, of which there were 4 sets, one per corner. Obviously it took a while to do that, but they'd been required to do drills so they knew what to do and where to go.

It didn't take nearly as long as I'd have guessed, though, given my own experience at Fermilab. The high-rise is only 15 floors. The building looks like an ice cream sandwich that fell and opened up. It also has 4 stairwells, but the atrium set were forbidden during the tornado drill--exposed to flying glass. So during the drill, 15 floors worth of people descended through 2 enclosed stairwells. I was on the 15'th floor. (There's a 16'th too, but almost nobody is there.)

It took about 30 minutes for us all to reach the basement. If a real tornado had been heading at us, it would have caught us with our pants down. I didn't even get into the stairwell for over 10 minutes.

4 times as many floors, and more people...

Keeping up with the news

Twenty five years later

I rode the bus to work with no radio and no internet. I saw nobody to speak with except Matt in the 3'rd floor who saluted me with a cryptic "It's your fault!" and walked on. I didn't know what to make of that – Matt had a strange sense of humor sometimes. There weren't a lot of people around.

I logged into the desktop, and the news was ugly. BBC's website was sluggish, the NYT was a bare skeleton page. I turned on the radio and listened.

It was obviously a war.

We'd been a long time without a major war, especially one on US soil. That kind of mostly peace couldn't have lasted forever, but I'd hoped …

The next thing I thought of was our 8-year-old youngest son marching off to war. I'd be willing to go in his place, but I was already too old for that. And there'd be a few years yet – I had no illusions about wars being short; they typically aren't, though the hostilities ebb and flow. In the event, we were rich enough to be able to trade money for blood, and didn't need large armies. So far. That trade only works if the war is mostly "somewhere else."

The culprits were identified surprisingly quickly. Or better say, "The proximate enemy was identified surprisingly quickly."

In the next few days the University sponsored a gathering to "work through" the news and the emotions, and with typical failure of imagination completely forgot to add to the roster of speakers a pastor or chaplain, i.e. somebody who regularly tries to comfort people suffering loss and pain. I didn't find that one professor's "travelogue" particularly moving or useful.

That blind spot persists, I'm afraid. Twenty-five years later I still don't see that the powers-that-be have a good grasp of what a religious war entails. Realpolitik may work with the rich and powerful rulers in a region, but in the end even authoritarian rulers hold their tenure by sufferance, and if the imams denounce you as an infidel there will be a change one day.

And it is curious what faith our aggressively secular rulers have in the evangelistic power of Mammon and John Locke.

Aztalan

Youngest Son and I went to Aztalan yesterday. It's a pity Van Buren wasn't interested in preserving the site, though it would have been amateur-excavated for souvenirs in any case; modern archaeology being, well, modern. One of the signs asserted that the population was about 300, which I gather they estimated from the fraction of the enclosed area devoted to housing and the number of posthole clusters they found for housing.

I wonder about that. The stockade (the outer one, anyhow, that they found postholes for) was about 2700 feet long, with "wattle and daub" to fill in the gaps between logs. That doesn't include defenses in or along the river, whose traces the Crawfish River would have obliterated long ago. And my own rough estimate comes up with room for more like 2-3000, though that estimate includes kids--so maybe 300 able-bodied men is reasonable.

And, pet peeve, they gave no estimates for how many people lived outside the city walls.

The mounds and stockade were built with stone tools. I'm not sure exactly how long it would take to cut down, trim, and haul the couple of thousand trees to build it. (Harder if the area was intensively used before hand, meaning they'd have to haul trees farther.) If it took a day for two men to cut/trim/haul a tree, that's about 4-5000 man-days for the stockade. You need farmers and fishermen too, so if you can spare a team of 20 to work on the job that's a couple of years of work (not in the winter or harvest time)--less than I expected. And then there's the weaving of small branches and vines, and the mud fill...

One of the mounds was a low kame that the residents built up a little, and one of the low mounds is almost completely gone. The others have been excavated and reconstructed.

They abandoned the city about the same time Cahokia was abandoned--something went sideways for the Mississippians, well before Columbus. People lived in the area for thousands of years, apparently, but the city was fairly recent. Figuring out what age the building postholes fit into is a bit tricky, especially since the area was heavily plowed for a while.

This part of the world doesn't have much in the way of ancient stone monuments.

Jeremiah

The Grim Weeper?

Dr Boli

"This explains why mad conspiracy theories are mainstream now: an idea that can be entertained only by someone with a limited experience of reality can be entertained by a majority of the people, because most people have only a limited experience of reality. What the phone tells us is more real than what the world outside the screen tells us."

I remember pre-internet, in a place without a lot of newspapers (or literacy) or even much access to radio news. Conspiracy theories out the wazoo. ("Queen Elizabeth has a book that explains this.")

Most information about the wider world came from unreliable sources, e.g. word of mouth. There wasn't much you could do about the news anyway, so its accuracy didn't matter -- a bit like entertainment.

Look for parallels at your own risk.

Fearing

The "Hymn Sing" tonight was an overview of Jesus' life, and we sang "What Child is This".

It's a little different from the nativity joy songs: "Good Christian, fear: for sinners here The silent Word is pleading."

A little reminder that something overwhelmingly powerful is here. Peter, and the Gerasene swineherds, and no doubt others I can't think of offhand, pled for Jesus to go away; they feared. Otto noticed that awe and fear seem similar -- we're not always eager to meet the awesome. Something about "that thoughts from many hearts may be revealed" probably plays a role too. We're small, and often unclean. And even redemption can be frightening.

Go play outside

and don't come back until suppertime.

Does early exercise make life-long changes in the body?

Perhaps for guinea fowl, when the life is relatively short. Maybe for people too, but that sounds like a long study.

Sparks a poppin

I read an interesting article that charged raindrops' charge is sufficient to, with time, blast through many protective coatings, including Teflon.

The question Ni, Berger, Butt, and their colleagues asked was what this charge does to the surface that the drop lands on next. To find out, the team released 35-microliter water drops, about the size of a large raindrop, containing a pinch of salt to mimic rainwater, onto a surface tilted at 50 degrees. The drops slid about four centimeters, picked up a charge, rolled off the edge, and then fell five millimeters onto a copper plate coated with a 60-nanometer film of Teflon, which is one of the most chemically resistant coatings on the market today.

That, btw, is the part that might not model real raindrops accurately--I'll address that in a moment.

The tilted surfaces were mostly chosen to mimic raindrops in the real world. One was a leaf from a Tradescantia spathacea plant growing in one of the researchers’ offices. Another was a PVC foam board from a hardware store. The third one was a sheet of transparent polystyrene sold as window glazing. Only the fourth one, the fluorinated coating on quartz, was more of a lab creation than something people usually see everywhere around them. The charges the drops picked up ranged from 0.2 nanocoulombs off the leaf to two nanocoulombs off the fluorinated quartz. A nanocoulomb in something the size of a raindrop works out to be a few thousand volts.

And yes, electrostatic effects (at raindrop speeds that's a good approximation) distort the raindrop into something pointy that creates a high voltage difference in the fraction of a second before impact, up to the kilovolt scale, which will cause a tiny dielectric breakdown. The researchers find damage to the surface.

The polymer coating is changed by the zap, and the underlying surface begins corroding.

The researchers identified the corrosion products on copper by Raman spectroscopy and X-ray diffraction. They found cuprous oxide and basic cupric chloride, the pale green compound familiar from weathered copper roofs. Elemental mapping of the damaged zones showed oxygen and chlorine flooding in and fluorine and carbon from the Teflon flooding out—exactly what should happen when a coating has been disrupted.

Another study looking at rain on solar cells finds a voltage spike as the drop rolls off.

It seems like a plausible real effect, and suggests that protective coatings (like paint) need to include other factors besides chemistry.

OTOH, the first other study I found (1953) found that raindrops had a little less charge. A nanocoulomb is about 3 esu.

The average measured free charge brought down by positively charged rain was 0.022 esu (.007 nanocoulomb) per drop, and by negatively charged rain was 0.031 esu (.01 nanocoulomb) per drop. The ratio of the negative free charge to the positive free charge brought down by rain was 1.2, while the ratio of the number of negative drops to the number of positive drops was 0.88.

That's quite a bit less charge on the natural raindrops that aren't sliding off a roof or something. Under a tree, the raindrops can pick up an order of magnitude more charge than an unimpeded drop, but still an order of magnitude less than sliding off flourinated quartz. So, under a tree, raindrops could hit a few hundred volts. Unimpeded drops, maybe a few dozen.

Some other studies of raindrops are comparable. This has obviously been a matter of some study--trying to understand what is the relationship of rain and lightning, for example.

And therefore, of course, one can find other, contrary estimates: "At the rain-forming level" 50 esu/gram times .03 gram (.3 for a heavy storm drop) is 1.7 esu (.6 nanocoulomb) (6 for a heavy storm's drop). And another that didn't find much difference in charge with raindrop size. And different proportions of positive and negative depending on the rain type (pre-monsoon, monsoon I, monsoon II).

And "The results show that the magnitude of the electric charges range between 1 and 50 pC (.001 and .05 nanocoulomb) and more than 90% of the charges are mainly carried by raindrops >1 mm, even though most of the raindrops are smaller than 1 mm."

Interesting. My guess from a quick-and-dirty literature review is that the effect in real life is smaller than the lab effect. Nature is always finding ways to erode what you build.

UPDATE: I neglected to mention -- the greatest electrostatic effects appear when the surface being landed on is metal, since charge re-arrangement is easy.