Grains of sand

How many grains of sand are there on earth?  That is a good question.  But a ball-park estimate is fairly simple.

We will look at fine sand (grain size = 100 microns), and coarse sand (grain size = 1 mm).

So a cubic mm can hold 1000 grains of fine sand, or 1 grain of course sand.  Obviously grain size is important.

There are 1x10¹⁸ cubic millimeters in a cubic km.

How many cubic km of sand, sandstone, etc we have Is a tricky question.  But if we say the average thickness of all sand for the globe is 200m (a thin number in any sedimentary basin, but most of the Earth is not a basin in the traditional sense.  The surface area of earth is 5x10 ⁸ km2, so a 0.2 km layer gives 10 ⁸ cubic km of sand.

This brings the total grain count to somewhere between 10³ x 10 ¹⁸ x 10 ⁸ = 10 ²⁹ for the fine sand, and a thousand times less than that, or 10 ²⁶ grains of the coarse sand.  If you want to know how that compares to the number of stars in the sky, ask an astronomer.

How many of your co-authors have you actually met?

In my meandering career from academia to government to private sector, and back into all the grey areas in between, I've been an author on a few journal articles, government reports, and other publications. Usually, these are collaborations between groups of separated people, not all of whom interact with every other member of the team.  For example, in the academic literature, I have a total of 21 co-authors, of whom I have met 9.  If we include government reports as well as papers, then I have 42 co-authors, of whom I have met 17.  I find it interesting that this ratio is so similar between the two types of reporting (about 40%).  So I was wondering: for those of you who read this blog and publish, is your ratio about the same?

Universities Australia sticks it to the Australian high technology industry

Universities Australia has launched a recent ad campaign decrying proposed funding cuts to university research.  This ad showcases the products of off-shore corporate giants which are trying to destroy the Australian high tech industry. 

The complicated scientific instrument pictured in the ad from 0:12 to 0:17 is something called a IMS-1280, manufactured by the American technology amalgamation Ametek under the brand name of Cameca, a European tech company which Ametek took over last decade. Ametek is perhaps the most aggressive corporate giant around in trying to leverage the recent high Australian dollar to destroy the Australian technology industry. 

Obviously, Australia is only a mid-size country, and most instrumentation in Australian universities is sourced from off-shore suppliers.  But many of these suppliers are good corporate citizens, who set up Australian subsidiaries, employ Australian graduates, and work closely with Australian agents, subcontractors, and scientists to sustain the high technology industries that define advanced economies in the 21^st century.  Indeed, one of these companies, the Japanese technology group JEOL, has an electron probe installed just across the hall from where the picture in the ad was taken.

Ametek is not a good corporate citizens.  Instead of collaborating with Australian manufacturers, they hire foreign lawyers to block sales around the globe.  While other companies reinvest in Australian research they hire slick Morden-like spokespeople to belittle the achievements of Australian academics.  And instead of helping Australian universities improve productivity and reduce costs through co-developed hardware and software modifications, they lock their customers into exorbitant service contracts, the proceeds of which allow them to underbid Australian companies whose instruments are generally preferred by researchers all over the world.

Every time one of the instruments pictured in this ad is purchased instead of an Australian equivalent, Australian universities lose hundreds of thousands dollars in direct payments from Australian companies and their international customers. It also means that Australian companies cannot create jobs for university graduates, such as those pictured in the first part of the ad.

The government is proposing cuts to university funding because of a revenue shortfall.  Revenue is down because aggressive corporate tactics by companies like Ametek are denying work to Australian companies, resulting in fewer hours worked, reduced income for the employees, and reduced income tax payment to the government.  So the approach of Universities Australia to showcase one of the most aggressive job-killers in their ad asking for government money is incredibly callous to all Australian trying to earn a living outside of the Ivory tower.

The Wool Sock’s Carbon Footprint

Four years ago, I blogged about the cognitive disconnect between the ecological perceptions of wearing wool and eating beef.  However, I did not actually calculate out exactly what the carbon footprint of a wool sock is.  Here it goes:

According to Wikipedia’s wool bale article, a bale contains about 60 fleeces, and weights 150 ± 50 kg.  This gives a fleece weight of about 2.5 kg.

This wool sock weighs about 100g, meaning that you can get about 25 socks per fleece.  A sheep produces one fleece per year.

A ballpark estimate from the NSW department of primary industries suggests that a medium sized (45 kg) adult sheep in warm weather needs about 500g of dry feed per day to survive.  If this feed is mostly cellulose, it will metabolize to produce about 800g of CO₂ per day, or 297 kg/ year. Assuming 25 socks per year, that gives about 12 kg of respired CO₂ per sock.

However, in addition to respiration, sheep also produce a fair amount of methane, which is generally considered to be 25 times more potent a greenhouse gas than carbon dioxide.   This paper estimates a methane yield of about 20 grams / day/ sheep, or about 7.3 kg of methane per year.  Using the 25 times multiplier, we get a CO₂ equivalence for that methane of about 180 kg / sheep/ year, which is a bit over half the direct respiration emissions.  Dividing by 25 socks/sheep gives is a CO₂ equivalent of 7.3 kg per sock (300 grams methane).  In total, our CO₂ equivalent emissions from the sheep are about 19 kg of CO₂ per wool sock- 12 from respiration, and 7 from methane.  This figure only includes the CO₂ footprint for growing the wool.  It does not include additional emissions from shearing, transporting the wool, spinning it into yard, and manufacturing the sock.  This is the same amount of CO₂ released by burning about 8 liters of gasoline (which is enough to drive a mid-size car 100 km), or one sixth the emissions of a top fuel drag race (with 2 cars in it).  So a hackey sack game with more than three pairs of new socks in it is worse for the atmosphere than this.

In contrast, a 50 gram synthetic sock (synthetics weigh less than wool) probably has a carbon footprint of 10-25 grams*.  It production is one THOUSAND times less carbon intensive than a wool sock.  So the next time some green evangelists starts looking down their noses at your car or your plate, check out their feet.

* In both the case of the plastic sock and the wool sock, the carbon in the sock itself is sequestered in the sock drawer for the lifetime of the sock, and in a landfill for several decades afterwards.  Unless you burn your old socks, which smells, or recycle your used synthetic socks into drink bottles, which is disgusting.