Rheology is essentially the study of how things flow, and in practice it is mainly the study of things that have complex flow behaviour, things that are between solid and liquids. A classic example is toothpaste. In the tube it is more or less a solid, but a firm squeeze turns it into a liquid that flows out onto your toothbrush.
I am at a conference in Sorrento, Italy. My hotel room is described as having a ‘hill view’, and as you can see from this picture taken from my hotel room, the description is accurate. That is a genuine Italian hill. In Sorrento, I will be talking about my work on paint drying, but I have a bit of time before the conference sessions start. So, I am also working on a course I am teaching next month for the EU network on RAtionalising Membrane Protein crystallisation (RAMP).
Few things are more boring and take less thought than putting a load of washing in the washing machine, but there is a lot of physics and chemistry going on inside washing machines. The basic idea is remove stains and dirt particles from your clothes, and to then carry them away down the drain. To do this washing powders and pods contain surfactants (soaps) to help detach stains and dirt from clothes, but then these molecules and particles must be removed from the clothes, and washed away.
We all know that oil and water do not mix. But they are not alone, oil, water and mercury also don’t mix, and so water, oil and mercury form three separate liquids, one on top of the other. And if you are really determined you can find not three but six different liquids, none of which mix with any of the others. This is what Ecklemann and Luning did*, to produce the test-tube shown to the lefy, containing six layers, each of a different liquid.
The top layer is a type of oil (petroleum ether), the next is alcohol’s slightly smaller cousin, methanol. Below those are a silicone oil, and then water (with potassium carbonate added so it won’t mix with methanol). Finally, at the bottom is a fluorinated molecule, and then mercury. The mercury is obvious as it is the only metal, the water, methanol and oil are dyed blue, yellow and red, respectively, so we can tell them apart.
I spent part of this week at the kick-off meeting for an EU-funded PhD training network: Engineered Calcium-Silicate-Hydrates for Applications (ERICA for short). The network is run from Surrey and I was invited along to give a talk, and to help out. These calcium-silicate-hydrates are better known as cement. Cement is, very roughly speaking, a type of artificial stone in the sense that when poured it crystallises to form a semi-crystalline solid. The world’s most widely used construction material, concrete, is basically cement plus gravel filler. Concrete is not the most glamorous, but it is strong and above all it is cheap, less than £100 for a ton.
I would to start this post by acknowledging how impressed I am with the style of the French guy who strode confidently onto Friday’s flight from Bordeaux to London wearing a large string of cloves of garlic draped around his neck. Some people just have natural style. As someone who does not, I am a bit envious. My PhD student and I were in Bordeaux as part of an EU research network (called RAMP) on crystallising proteins. There is a research lab in the suburbs of Bordeaux that is world leading at what is called microfluidics — essentially plumbing but instead of pipes centimetres across that move litres, microfluidics has pipes that are less than 1 millimetre wide and move as little as billionth of a litre, a nanolitre. The channels above in the microfluidic device shown above are only 0.15 mm wide.
Over the last six months I have been thinking a lot about the movement of small solid particles in liquids, but a couple of weeks ago I came across examples, that were new to me, of the reverse. The motion of liquid droplets or gas bubbles in solids. I think they are fascinating. One example of liquid droplets moving inside a solid, are pockets of brine (i.e., salty water) moving inside ice.
The life of an academic involves a certain amount of travel, in my case to Manchester in January. This as glamorous as it sounds, the drizzle has been unrelenting. Although on the bright side I was able to finish my talk for tomorrow in the Lass o Gowrie, which I can recommend; friendly barstaff, and the Citrus IPA was good. Tomorrow, I am going to give a talk about growing crystals, in particular growing crystals of a small molecule called glycine. We* studied the glycine molecule because when crystallised from water, it forms not one but two types of crystals.
I am rewriting a computational modelling project on modelling the stock market, so I am doing a bit of background reading. Fortune’s Formula by William Poundstone is a good general-interest description of some work from the 1950s onwards, on developing models for both the stockmarket, and gambling in casinos. In terms of mathematical modelling, gambling (aka investing) in the stock market, and gambling in casinos are almost the same — the aim is the same in both: maximise the money acquired while minimise the risk.
Universities that do research as well as teach, like Surrey, are funded from many different sources, and their finances are complex. But roughly two-thirds of the money the Department has to pay my salary comes from student fees and government funding for teaching, leaving one-third of my salary to be paid for from research income. The distribution of my time between teaching and research is maybe half-and-half*. Teaching is subsidising research, in the sense that student fees are paying my salary for some time when I am doing research.