Another reason I’m glad I left Sydney

According to the news, a motorist jumped on the brakes after pulling in front of a 50 bike peleton in Sydney this working. The resulting pile-up included half a dozen former and current Olympic riders, a jack-knifed semi-trailer, and Kate Nichols, who had only just returned to riding after being injured in the German 2005 crash that killed Amy Gillett. Thankfully nobody was killed this time. It ain’t just motorists who have such a callous disregard for human life, either. Yesterday, also in Sydney, two teenage pedestrians were arrested from throwing a boulder off of an overpass at a car below. The arresting officer was patrolling on a bicycle.

Research paper word clouds

Brian at Clastic Detritus has word clouded two of his papers, creating what has to be the coolest word cloud use ever. Having no shame, I am going to copy him.

Here is Birch et al. 1997:

abrasion age al andalusite arnaud associated australia australian basaltic carapooee concentrates contact corundum crystals deposits diamond et figure formation fragments generally geological gold grains granites gravel heavy hills likely ma maghemite metamorphic minerals mm pb present range region report rocks rutile sapphires showing source south spinel sutherland typical victoria zircon

created at TagCrowd.com

Here is Klemme et al. 1998:

ablation al analyses analysis analytical apatite ca compositions concentrations coupled elements et fragments germany glasses heidelberg hf homogeneity icpms in-situ inductively interest isotope laser major mass materials measured minerals nb performed phosphate plasma prepared reference relative results several silicate sims spectrometry standard table techniques titanite trace university used values zr

created at TagCrowd.com

Note that both papers pass the suck-up test- the PhD advisor's name (from references) is not a prominent word. This is unsurprising, given that the people who actually wrote these papers haven't been students for some time.

The appearance of Sutherland raises a self-referential alert in Birch et al., but other than that the lists seem pretty topical.

Now I need to get some of my own manuscripts submitted so that I can do this on them!

Musical interlude

I really need to get some work done on a paper, do real work, get family time, etc., so I'll leave you with this musical quiz meme courtesy of sciencewoman:

The rules:
Step 1: Put your MP3 player or whatever on random.
Step 2: Post the first line from the first 25 songs that play, no matter how embarrassing the song.*
Step 3: Post and let your magnificent readers guess what song and artist the lines come from.
Step 4: Strike through when someone gets them right
Step 5: Looking them up on Google or any other search engine is now considered fair game, as the post is very stale.

*I have altered the methodology by excluding songs where the first line is the name of the song.
(drum roll)

12.Cue the music, curtain falls
15.How long how long how long/ will we take to come undone
10.This wide brown land’s a crock of shit
11.Humpty Dumpty sat on a wall
13.Made a promise to myself
14.Quando você passa eu sinto seu cheiro
24.Ain’t no talkin’ to this man (Let him fly; Dixie chicks) - rebecca
9.Ninguém passa aqui sem cantar samba-reggae
5.Somewhere a strut
3.I’m ready / I'm ready for the laughing gas (Zoo station -U2) - jrepka
23.You’re dangerous ‘cause you’re honest (Who’s gonna ride your wild horses; U2) -sciencewoman
---Voyager 2 at Neptune---
25.I know/ that the sunset empire shutters and shakes
16.You never called
22.Many is the time I’ve been mistaken (American Tune - Simon & Garfunkel) -Sachqua
E.C. You're a real tuff cookie with a long history (Hit me with your best shot- Pat Benatar) - Tuff Cookie
20.Good morning the worm, your honor (The Trial Pink Floyd) - Steve Bloom
19.You know that I care
18.I’m sailing away (Come Sail Away; Styx)-jrepka
7.Billy Rose was a low rider (Prison Trilogy- Joan Baez)- silver fox
--Apollo 11---
17.Here you’re comin’ on so nice to me
21.Let’s all get up and dance to a song (Your mother should know; beatles) - jrepka
6.The day breaks
8.Shapes
1.Well East coast girls are hip (California Girls- beach boys)-Ecogeofemme
4.We-e-e-e-e-ellllllll / You know you make me wanna (Shout Isley brothers) - Tuff Cookie
2.She comes on like a rose
---Sputnik---

And, for extra credit, a line for everybody's favorite igneous blogger: (see 1980)

UPDATE:
In an effort to assist the local sedimentologists, I've put the songs in stratigraphic order, with a few space age marker beds. Still left:
1 Beatles song, 1 Pink Floyd song, all 3 Australian and both Brazilian artists.

Carnival of space

The first anniversary issue of the carnival of space is up at Why Homeschool.

Thorium / uranium ratios and atomic power

Thorium and uranium are the only two actinide elements that are stable enough to have survived since the formation of the solar system without being destroyed by radioactive decay. They are geochemically similar. Both are strongly lithophilic, meaning that they form oxides and dissolve into silicate melts, without entering into metallic or sulfide phases. Both elements are fairly refactory, meaning that they condense earlyish in the solar nebula. And they are both incompatible during mantle melting. This means that they do not fit into the crystal structure of mantle minerals, so when a planetary mantle undergoes partial melting, the vast majority of the U and Th dissolves into the melt, and relatively little remains in the mantle mineral residue. This is because Th and U are both large +4 cations under most conditions, and mantle minerals (made mostly of Mg, Si, Fe, Al, and Ca oxides) don’t have any crystallographic sites into which such ions can fit.

Of the two, Th is slightly more refactory and incompatible, but not much, so their ratio doesn’t change a whole lot. As a result, the solar ratio (about 4) is not that different to the ratio of the lunar crust, the Martian crust, the Earth’s crust, and the Earth’s mantle. For most meteoritic, igneous, and mantle rocks, Th/U is about 4.

This number seems to have been picked up on by the more extreme proponents of nuclear fission- generated electricity, as evidence that even if we run out of uranium, there is still lots more thorium. Technically, this is true. If we were to run the entire solar system through a refining mill with a 100% recovery percentage, then at the end of the project, we would have 4 times more thorium than uranium. But the real world doesn’t work like that.

Even though the crustal Th/U ratio is also about 4, we aren’t conceivably going to dig up the entire Earth’s crust either. So the bulk crustal (or planetary) Th/U ratio is not really relevant to anything other than science fiction. What is important is the ability of geological processes to concentrate these elements into a highly enriched deposit, which we can then mine for a reasonable cost and effort. And this is where U and Th start to differ.

Although these two actinides are geochemically similar under most conditions in the solar system, there is one key difference in their chemistry. In the presence of abundant oxygen, U can oxidize from +4 to +6. For the first two billion years of Earth’s history, this was irrelevant. But about 2.4 billion years ago, free molecular oxygen first started appearing in Earth’s atmosphere and surface waters. And this changed everything.

Thorium can’t form a +6 ion, because Th +4 has the same electron configuration as the noble gas radon- all the electron shells are closed. But uranium has 2 extra electrons to lose, given enough oxygen around to take them. And the hexavalent chemistry is quite different to the tetravalent. In the +4 valence, both U and Th are generally insoluble under most hydrologic conditions. But U +6 forms a uranyl ion (UO₂⁺⁺), which is highly soluble in most geologically reasonable waters.

As a result, for the last 2.4 billion years, uranium has been dissolving from oxidized rocks, flowing through aquifers with the groundwater, and then reprecipitating wherever a later chemical reaction consumes the oxygen in the water. What this means is that uranium can be- and is- concentrated by a geologic process which has no effect on thorium.

The result is that uranium forms deposits more frequently, and of higher grade, than does thorium, which is distributed much more evenly across a wide variety of rock types. Today the world has a uranium reserve of 4 million tonnes, with a resource maybe ten times larger. This is despite not actively exploring for the substance since the cold war ended. Thorium, strictly speaking, doesn’t have reserves at all; it is currently only recovered as a byproduct of rare earth element mining. But based on known occurrences of monazite (LREE)PO₄, which can contain a few percent of Th), the estimated resource is about 1.5 million tons.

So although the bulk crustal concentration of thorium is higher than that of uranium, its simpler chemistry means that it does not get concentrated into mineral deposits as easily. So while claiming that Th is more abundant is technically correct, it isn’t the sort of technicality that one should base energy policy on.
[edit: typos]

Effect of carbon tax on gasoline prices

This is a back-of-the envelope calculation to show what the approximate effect of carbon tax would be on fuel prices.

First, figure out how much carbon is in your unit volume of fuel.

For liters, this is easy. Gasoline is about 85% carbon by mass (the rest is hydrogen), although this number may vary based on blends and additives. The density of gasoline is about 0.73 kg/l so multiply the density by the carbon fraction (.73 x .85), and you get 0.62 kg carbon per liter.

For gallons, just multiply 0.62 by the number of liters per gallon, which is 3.78.
3.78 x .73 x .85 = 2.35

Most proposed carbon prices are by the metric tonne, which is 1000 kg. So a $10 per tonne carbon tax would be $1 per 100 kg, or one cent per kg.

With 0.62 kg/liter, this amounts to 0.62 cents of excess tax burden per liter of fuel.

For a gallon, this is 2.35 cents per gallon extra in tax.

However, there is a catch. Producing and transporting gasoline to the end user requires the use of gasoline (or equivalent). I don’t have a good figure for this (anyone?), but I have a vague recollection that each unit of fuel you use requires an additional 0.2 units to get from the ground to your car. So if these costs are passed on to the consumer, a $10/tonne tax would cost 0.75 cents per liter- a 20% increase over the 0.62 cent rise.

The $10/tonne tax on a gallon of gasoline would be 2.8 cents per gallon, up 20% from 2.35.

Most carbon tax proposals call for a tax rate somewhere between 10 and 100 dollars per tonne of carbon, which would equate to a tax of 2.8 to 28 cents per gallon. The current federal tax is 18 cents/gallon, and the current state tax average is about 28 cents/gallon. So even a high carbon tax would be of a similar size to current taxes.

28 cents is only about 8% of the current cost of gasoline ($3.50/gal)- with most of that cost coming from the high price of oil caused by poor supply and high demand. So even the most extreme carbon tax scheme floated by reasonable people would have a much smaller effect than market forces, slightly larger than federal taxes and similar to state taxes.

I’ve heard fearmongering that a carbon tax could add $2 to the price of gasoline. This would require a rate of 200 cents / 0.28 cents per carbon tax dollar = a carbon tax of $714. I can't even find nutjob greenies who support a tax that large.

Of course, if you really want to reduce the price of gasoline, you need to reduce global demand for oil- or hope that supply will continue to increase forever.

92Nb in meteorite accessory phases

I must admit to being a fan of the element niobium. It is quite possibly my favorite element on the periodic table. So imagine my delight when I came across this paper on short-lived Nb chronology of meteoritic zircon and rutile.

Today, Nb is monoisotopic. But although all isotopes with a mass other than 93 are radioactive, ⁹²Nb has a half-life of several million years, and is stable enough to have still been present in the early history of the solar system. It decays into ⁹²Zr.

So, the ⁹²Zr we find today is a combination of the solar systems original ⁹²Zr plus the solar system’s original ⁹²Nb, all of which has now decayed. Before the ⁹²Nb decay was complete, there would have been less ⁹²Zr around relative to the other Zr isotopes. So a phase with high Zr and low Nb (e.g. zircon) should show a ⁹²Zr deficit if it formed while ⁹²Nb was still around.

Similarly, a phase with high Nb and low Zr that formed when ⁹²Nb was still live should have a ⁹²Zr excess. Rutile is a prime example of a high Nb, moderate Zr phase.

So, armed with a multicollecter ICPMS and a laser, our intrepid authors pick meteorites with zircon and rutile in them, fire away, and observe the expected isotopic anomalies.

They then combine their results with those of other short-lived P process isotopes and attempt to constrain the nature of the supernova that created the isotopes, and the time between this supernova and the formation of the solar system.

I honestly don’t know enough about astronomy to know what an SNII-sources neutrino-driven wind is, so I can’t really comment on that unless a friendly blogging astronomer can help me out.

As for the 10 MA time period, this really depends on the exact age of the analysed phases. Amelin et al. 2002 give the age of CAI as 4567 MA, with chondrules being 2-3 Ma younger. So unless we know the age of the Chaunskij zircon relative to CAI’s, it isn’t apparent what this 10 MA means. In theory either U-Pb or Hf-W should help answer this question, but the absolute age of this zircon isn’t given. I didn’t chase up the references for the reported values for other short-lived P-process elements.

Full paper:
Yin, Q.Z., Jacobsen, S.B., McDonough, W.F., Horn, I., Petaev, M.I., Zippel, J. (2000). SUPERNOVA SOURCES AND THE 92Nb-92Zr p-PROCESS CHRONOMETER. The Astrophysical Journal,, 537, L49-L53.

Reference:
Amelin et al. 2002 Science Vol. 297. no. 5587, pp. 1678 - 1683

Torch relay smashing success for China

So, the Olympic torch relay came and went yesterday, and the lemming family escaped unscathed. The media are all calling it a success and a demonstration of Australia’s ability to host events.

What happened was this:
Amid fear of interruptions by Tibetan protesters, the Australian police put a huge cordon of security around the torch. China responded by busing tens of thousands of students and other expats in from the big east coast cities, creating a sea of red.

And while the police and TV cameras were occupied with the running of the torch and the area immediately surrounding it, gangs of Chinese toughs roamed the streets after the cameras and officials passed by, beating the shit out of anyone with gold, blue, or white on. The SMH has details (via Ned Kelly).

The big winner, or course, is political correctness. After all, symbolic security was perfect. The torch went around inner Canberra like clockwork. With that success, who cares about the safety of the people who actually live is this town?

And while the relative morality of genocide vs. imperialism can be debated, there is no doubt that this time around China is more media savvy than the pro-tibet folks. After all, they played the Australian media and security forces like a fiddle. In contrast, I reckon that the Tibetan activists can be their own worst enemy. I mean, duh, who started the torch relay tradition back in ’36?

Jon Stanhope said, “I uphold utterly the right of anyone to use the leg of today's relay as an opportunity to have their voice heard”. What he meant was, “In order to make everything look slick, we will let the Chinese government and their henchmen chose who gets to express their opinion in Australia’s capital today.”

Way to advance Australia fair, Jon. And it is my deep regret that the blanket of PC conformity that now smothers the Australian nation prevented this sort of thing from happening again.