by Tyler Cowen
on June 18, 2013 at 12:55 pm
in Uncategorized |
1. Would you settle for a flying train?
2. Did killing lots of people in WWII postpone the great stagnation?, and more here.
3. Did the Romans make better concrete than we do?
4. Where do NBA players come from?
5. Is there a classical world at all? And Fitch on Chinese credit.
6. On the narrowness of the Myriad Genetics ruling.
#1 Flying Train:
Reminds me of ideas presented long ago to have passengers board cargo-container like pods at the terminal that are then loaded into the planes. Pods have seats etc. and are form fitting inside the plane. Removes the hassle of boarding, improves turnaround time etc. I even saw a prototype that had windows that’d align with plane windows.
So much for ideas. Never took off. Neither will this one, I predict.
Changing transportation modes sucks. If I could be loaded into a pod, I’d settle for somewhat longer trips and pay somewhat more money if it means I get delivered to my destination without needing to pay attention to what’s going on.
This also applies for my daily commute.
Flying trains don’t work for the same reason that we don’t have passenger planes with a body similar to a B2 bomber. They are easy to build but extremely unpleasant to fly as a passenger. The further you sit away from the center of a plane, the stronger the G-forces become during rolling movements and turbulences. Nobody would want to sit 50 feet away from the center of a plane when it turns into a steep bank.
Just call them “roller coaster style” seats and sell them to the adventurous at a premium.
Nobody would want to sit 50 feet away from the center of a plane when it turns into a steep bank.
People do that tens of thousands of times a day without complaint.
“as” means the center line of a plane, not the front or back.
ok, still don’t get it. Are there trains that are really wide? or is someone thinking about flying trains sideways? You’re not getting 50 feet away from the center without that.
and you definitely don’t want to be on the bank.
But some French guy has a pretty computer model of this contraption flying effortlessly.
My biggest concern would be what’s holding each pod to the flying frame. No way in hell I’m signing up for this until it has had a few years of successful service without a compartment becoming dislodged 12,000 feet up.
Well, as long as he’s French.
Hey, make the pods piggy-backing puddle jumpers that get dropped off en route and now we’re talkin’!
#3, the primary decay mechanism of modern concrete is the steel reinforcing. Chloride ions penetrate the concrete and corrode the steel, causing it to expand and destroy the concrete from the inside.
Concrete has little tensile strength, so steel needs to be added to allow concrete to span any appreciable distance, or to rise any significant height. And because steel prevents sudden, catastrophic failure, it’s basically required by every modern building code outside of a few special cases. Roman concrete has no steel reinforcing, so it’s not surprising that it seems more durable. But it’s not an especially meaningful comparison.
Indeed. Concrete is a highly engineered product, and the notion that the Romans did it better hardly fits the facts. For instance, the steel reinforcing problem has been solved for many applications by synthetic fibre reinforcement: http://www.elastoplastic.com/
That depends. The best concrete that we can do today is better than the Roman concrete. But, the best Roman concrete was still better than our average concrete in many ways, such as durability.
Also, the explanation for the higher durability of Roman concrete doesn’t have anything to do with steel reinforcing.
Anyway, the whole assumption that a civilization always progresses socially and technologically is plain wrong. A civilization can also decline and collapse. The ancient Greco-Roman civilization managed to sustain a declining trajectory for several centuries, according to the archaeological data (for example the number of dated Mediterranean shipwrecks shows a dramatic peak in the 1st century AD if compared to all the following 16 centuries).
I don’t get your point of comparing best’s to averages. How is that fair or relevant?
The tallest Chinese man is taller than the average Dane. Doesn’t make us go around claiming “Chinese are taller than Danes”
I assume that the average Roman apartment builder could not use stick-and-frame construction, cover it in stucco, and then call the result “luxury.” Some give and take there. The option of low cost construction, but fewer buildings to last centuries.
I assume that the average Roman apartment builder could not use stick-and-frame construction, cover it in stucco, and then call the result “luxury.”
You mean like tying wooden poles together, covering the walls with mud and the roof with thatch?
>Anyway, the whole assumption that a civilization always progresses socially and technologically is plain wrong.
The assumption that technological and (especially) social progress even exists is pretty controversial. But if it does, that we have the Romans beat isn’t controversial.
This bit about Roman cement being environment friendly was cryptic too:
“Another remarkable quality of Roman concrete is that its production was exceptionally green, a far cry from modern techniques.[…] The problem is that manufacturing Portland cement accounts for 7 percent of the carbon dioxide that industry puts into the air. […]The Romans made concrete by mixing lime and volcanic rock. ”
So where did Romans get their lime from if not by roasting CaCO3? And if so, weren’t they producing CO2 too?
It’s not “cryptic”
+1, It’s pre-Industrial, so it’s automatically environmentally friendly. … if you’re a moron.
a) They are talking about chemical decay of concrete. Steel is irrelevant. Funny thing is that chemical decay in modern day concrete is more driven by agregate quality (sand and/or gravel) than Portland cement quality. Poor science journalism.
b) Selection bias: the scientits are only analized and made conclusions from concrete that lasted 2K years. the original press release states that the only analyzed a few samples of concrete of an specific region. What about fallen roman ruins? It may not be the research objective, anyway extremely poor science journalism for saying things scientists did not say.
c) Italy has really nice weather. Nowadays, there’s concrete that can resist periodic cooling below water freezing point. The water trapped in the concrete becomes ice and you don’t see cracks. Guess why there’s concrete bridges in Canada and Norway.
d) Volcanic ash? You mean flyash? “Flyash used in concrete is a mature technology. Thirty percent of the flyash in the US is recycled into making concrete.” http://flyash.sustainablesources.com/ Perhaps what this study provides is a really long term test of flyash use in concrete mix. But, short-medium benefits of flyash use are already known. Poor background research.
The research did showed the results of an unintended 2000 year test of a technology already used that consist in adding flyash to concrete mixes. Sadly, the below average science journalism just make you say bullshit. A Roman shot in the dark success does not make present day knowledge inferior.
It is the ash that makes Roman concrete stronger and more durable than Portland cement. We can do the same thing with coal ash from power plants (the Hoover Dam was built this way), only an economic supply of high-quality ash is not always readily at hand for every market. Kind of a problem with volcanic ash as well.
I would be surprised if flyash and volcanic ash were chemically similar given their completely different genesis.
This doesn’t seem to be “news” either. I can recall reading books in junior high that mentioned volcanic ash as the secret ingredient in Roman concrete.
#1: I will not settle for anything less than a flying car, preferably one with a flux capacitor.
And I want it yesterday!
So there is no Great Stagnation! It is all labor supply and wages of the post-WW2 period increased greatly because there were restrictions on labor supply:
1) Lots of dead Westerners and society guilted woman back into the house to repopulate the world.
2) Cold War divided the world and markets.
3) There was a baby bust in the early Depression.
So what has happened. Labor supply exploded. More countries (China anybody) joined the global economy, women now are part of the workforce, which is marginally counteracted by falling birth rates and increased education for young people. (Teenagers work a lot less than they used to.)
There was a big increase in per capita wealth during the Black Plague. A big chunk of the population died and the rest got their stuff.
#1: Cool idea, but I’m not sure I want TSA fondlings at the train station too!
Cavity searches in a cattle line are conceptually the opposite of flying cars.
At the end of WWII, thanks to war production AND war destruction, 75% of all the worlds industrial capacity was located in the states and provinces that surrounded the Great Lakes. It was a nice place to be in at that point, but we probably have been experiencing some reversion to mean over the last 60 years
“Flying trains” would be killed by the security theatre. There’s no way any regulator would agree to let you treat it like a train – just get on and off, without providing your name, having your bags x-rayed and so on.
The big overhead associated with flying is due to all the security rather than due to getting off one vehicle and on to another.
#2 good hypothesis, but it’s not complete. The United States’ casualties as a percent of 1939 population was among the lowest of all major combatants, but American workers were one of the greatest beneficiaries in the post war era. The fact that industry in other countries was destroyed, as ElamBend alluded to, was probably a huge factor.
#3 I know little of construction tech, but this link indicates part of the appeal of Portland cement is how quickly it sets. Apparently this was a big factor in it winning in the marketplace vs. other mixes of cement which can take longer.
from:”Lime cement takes a long time to cure, and while the ancient world had lots of time, today time is money.”
Every few years for the last 40 years (mayber longer for all I know), someone will burst forth claiming to have made the revolutionary discovery that Roman cement was better than modern cement. The material alluded to here was a geopolymer and the modern geopolymer industry has been around (small but growing) for about 20 years.
interfluidity.com/v2/3487.html argues wwii reset “inequalities” that predominated prior to the war. inequalities that remind one of today’s. too many entrenched interests.
No one, today, wants to talk about entrenched interests having any kind of large impact. So when Bank of America gets caught with its hand in the cookie jar again, stealing from its customers again, the powers that be just kind of close their eyes … again.
And Tyler in The Great Stagnation never mentions anything like inequalities or entrenched interests. Instead we just get a list of stuff that’s run out so nobody is ever at fault. It’s kind of just like with Bank of America, no one’s at fault. If you just read The Great Stagnation our leadership is never at fault, ever.
I like steve randy waldman’s interfluidity intuition much better.
And Tyler in The Great Stagnation never mentions anything like inequalities or entrenched interests.
This was posted two days ago:
“The great stagnation will end for a lot of people but not everyone,” Mr. Cowen said. “I think there will be great breakthroughs but the distribution of those gains will go to owners of capital and intellectual property.”
That’s from the new book.
But my recollection of the old book could be mistaken.
TGS talks a lot about the lack of median income growth … the average has grown due to the top, so that’s the inequality feature. The discussion of the financial system is also critical, in part reflecting entrenched interests or at least diminished social value. My worry about the new book is that we just have to accept these inequalities and interests as given and live with them.
#4. I was about rag on the silliness of the “where do NBA players come from” map, but instead I will outsource my criticism to xkcd:
The criticism doesn’t apply, if you look further down. New England is significantly under-represented. Even if most basketball players in the era discussed were black, there are patterns which don’t track well to U.S. black populations – Kentucky and Indiana aren’t particularly heavily black states, and South Carolina doesn’t generate a lot of NBA players. (Louisiana and Mississippi also do well, which is not surprising, though.) California doesn’t have nearly the black percentage of population as Georgia or Alabama, but generates a similar number of NBA players per capita. (As does Wyoming?!)
Oops, I only looked at the first map. You’re correct that maps further down the page deal with the population issues. My error.
The Bloomberg report on Roman concrete is crap – they’ve have done better to transcribe one of the press releases from Berkeley.
(Full disclosure – I’ve taken classes from Monteiro, many years ago, and have worked in U.C. Berkeley’s concrete lab.)
The press releases explain that turning limestone into lime is done at a lower temperature than is turning limestone and clay into portland cement. As pointed out in the press releases, and in comments above, using lime and pozzolans instead of portland cement means longer setting and curing times, which is a significant problem for a lot of ordinary construction. You’re also not going to be able to do this with lime-pozzolan concrete. (TINGS)
Volcanic ash isn’t the same thing as fly ash. The ash available at Pozzuoli is chemically better than fly ash, primarily due to its aluminum content. However, it’s not going to be chemically the same as volcanic ash elsewhere, so other regions may not have the same results.
Nice info & nice post.
Oops. Forgot a </b> after “and clay”. Sorry.
This text is priceless. Where can I find out more?
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