Wednesday, 30 November 2011

Granular Dynamics and Asteroid Formation - Pt 1 - Lecture


Another fantastic public lecture at Nottingham University ! These really are wonderful FREE events that the local community can take advantage of.

This one was titled "Granular Dynamics : Patterns in the Sand" and was presented by James Clewett, a 3rd yr PhD student in the University of Nottingham Physics Department.

Granular Dynamics is the study of how systems containing large numbers of particles behave. For example :
* Dry Sand (and how it forms sand dunes)
* Wet Sand (and how it can be used to form sandcastles)
* Mixing of powders in foods and medicines (want to ensure even mixing)

An interesting property of granular systems is that they can behave as solids (e.g. damp sand), liquids (e.g. sand in an hour glass) or gases (e.g. sand in a dust storm)

Another aspect of the behaviour of granular systems, especially those that are being agitated in some way, is the "Brazil Nut Effect", so called after the phenomena shown by Brazil nuts rising to the top of a bag of mixed nuts.

James and his colleagues have been looking at asteroids and considering whether they may have a granular structure.

One piece of evidence that at least some asteroids may have a granular structure came with the discovery of the KW4 asteroid (see here), which comprises a main asteroid about 1.3km in diameter, which is orbited by a "moon" that is about 360m in diameter. By measuring the speed of the orbit of the moon, it became clear that KW4 had a low density and must therefore be quite porous.

Another piece of evidence was the finding that, whilst small asteroids have a variety of spin speeds, larger asteroids only spin slowly. This is important because it is consistent with a granular nature. Granular bodies are weak and tend to break up if subjected to larger stresses (i.e. being massive and fast spinning).

A third piece of evidence was found when the Japanese Hayabusa Space Probe visited the Itakawa asteroid (see here and especially here) with the aim of scooping up some of its surface and bringing it back to earth. The probe photographed the asteroid in great detail and it can be seen that it has a very rocky surface (at least in parts, some areas appear very smooth). This kind of surface is consistent with operation of the "Brazil Nut Effect", possibly on timescales of millions of years. James' group has written a paper on the possibility of another asteroid, Eros, also having a similar surface appearance (see here)

NSB has found itself going back to the pictures of Itokawa and gazing at them wondrously and for some considerably time.

As an aside, NSB found a really interesting paper titled "Asteroid Density, Porosity and Structure" (see here) on the Internet whilst preparing this post. About half way through there is a cracking chart showing the different structures of various asteroids, and a lot of other information besides. The suggestion is made that these low density asteroids are basically big piles of rocks and sand - essentially a pile of rubble!

The lecture covered a number of other aspects of granular dynamics. NSB suspects that it would do a pretty poor job of explaining these so is going to respectfully point you, dear reader to the University of Nottingham Granular Dynamics Group Webpage (see here), where you can find out much, much more about the research that goes on there. There is also an interesting video on the behaviour of vibrating granular systems as part of the "60 symbols" series (see here)

Oh, and you can find out more about James, including his past as a World Champion Tetris player, at his website (see here)

Links (same as those embedded in text above)
KW4 asteroid
http://en.wikipedia.org/wiki/(66391)_1999_KW4

Itokawa asteoid
http://en.wikipedia.org/wiki/25143_Itokawa

Asteroid Density, Porosity, and Structure
www.lpi.usra.edu/books/AsteroidsIII/pdf/3022.pdf

The Brazil Nut Effect on Eros
http://www.nottingham.ac.uk/~ppzmrs/granular/eros.pdf

Summary of reports in "Science" of Hayabusa imagery
http://www.isas.ac.jp/e/snews/2006/0602.shtml

University of Nottingham Granular Dynamics Group :
http://www.nottingham.ac.uk/~ppzmrs/granular/index.php?dpage=home

Granular Dynamics at the 60 Symbols series
http://www.youtube.com/watch?v=HKvc5yDhy_4

James Clewett's Website
http://www.jamesclewett.com/

Granular Dynamics and Asteroid Formation - Pt 2 - Modelling at Home

About half way through the lecture on Granular Systems at the University of Nottingham see Part 1 here the presenter began showing some short videos of how the particles in granular solids behaved when agitated. One of the effects shown was the "Brazil Nut Effect" and, on seeing this, Number One son leaned over and whispered "We could do this in Phun".

"Phun" is a free software program that allows you to create shapes and simple machines that can then be "run" in an environment that has gravity, air resistance and other characteristics of the real world. I could go on but, to be honest, the short demonstration video below says it all. Dear Reader, if you can watch this without a sense of "wow" and a wish to have a go yourself, then perhaps you need to check whether your heart has somehow turned to stone. . .


Awesome, isn't it! You can download the software, for free, here (scroll down to the section called "old verions" to get the free version).


Now, to get back to the lecture. NSB had a go at modelling (more or less) the "Brazil Nut Effect" in Phun.

This was done by making a box that had a load of small balls inside it, as well as one larger ball. The whole thing was then agitated by two triangular cams located below the box that were rotating at about 100rpm. Somewhat to NSB's surprise, the model worked, with the larger ball rising to the surface each time. Three screenshots of a typical run are are shown below, one from the start, one from the middle and one at the end (i.e. when the larger ball had reached the surface)


In the example above, the larger ball is twice the diameter of the other balls. What do you think would happen if the larger ball was three, four or five times the diameter of the other balls? Would it rise to the top even faster? BFTF certainly thought so and tried it. The results are shown below (they are all the time to rise to the surface, the average of three runs and are corrected for the fact the larger balls don't have to rise so far before the get to the surface)

2 x diameter of standard ball : 125sec
3 x diameter of standard ball : 107sec
4 x diameter of standard ball : 131sec
5 x diameter of standard ball : 87sec

Not exactly the clearest of trends is it? The result for the 4xdiameter ball seems a little out of place, so BFTF ran that one a further three times to get more data, and found the average to go up to 143 seconds for his trouble.

That really does seem weird, and BFTF could not really understand why there was no trend. NSB also noticed that, once it had reached the top, if the ball moved to the side it would often get "dragged down" towards the bottom of the container for a while before moving towards the centre and rising to the surface.

What was going on? NSB had no idea. . . until it noticed this article that described how particles behaved like a fluid, with convection currents (like peas in a pan of boiling water).

This would imply that the standard balls would also rise to the surface, as they were just caught in the current, as it were. NSB tried this in Phun, but found the marked ball to stay resolutely where it was and not move upwards particularly.

NSB suspects that this is because the balls are all the same size and so pack together really well, thus limiting movement, so perhaps using two or three different shapes of particles would work better.

Out of idle curiosity (and, in case you are wondering, NSB does have a day job that pays all the bills so is not actually idle), NSB then took the "4xdiameter of standard ball". . .er . . .ball and progressively reduced its density down from 2.0g/cc (the same as all the small balls) to 0.5g/cc. Dear Reader, what do you think happened this time. . .?

Well, the results are shown in Chart below:


Presuambly, giving the larger ball a density much bigger than 2g/cc would result in it being too heavy to be "pushed" to the surface, but NSB has not tried this.

So there you. "Phun" - it is brilliant, and you can do real physics on it.

If you haven't already, why not download it and have a go - you know you want to.

Drug Delivery, targeted therapeutics and the future of medicine

NSB went to a fascinating public lecture at the University of Nottingham today. Part of the “New Science Sessions” series, the talk was titled “Drug Delivery, targeted therapeutics and the future of medicine” and presented by two PhD students - Eleanor Grimes and Jennie Lord.

Slightly scary title, it has to be said, but the inclusion of “and the future of medicine” certainly gives them a lot of scope. It’s a bit like a politician giving a talk called “Housing Benefit, targeted welfare and what might happen in Europe over the next hundred years”.

But anyway.

Jennie Lord began the presentation and explained that there are many ways that drugs can be administered (injection, absorption through the skin, orally etc) and that, of these, oral administration is preferred for its obvious attractions of ease, convenience and relatively low cost. A show of hands in the audience indicated that there were far fewer people who would be happy about taking a weekly injection than there were people who would be happy with a weekly tablet.

The example of Ibuprofen was given. This is a drug that blocks hormones that cause pain, welling and inflammation. When given via a tablet, it takes approximately two hours before the peak effect is achieved. Now, the pain relief would come a lot sooner if Ibuprofen were given via injection, but that would be more expensive, more painful (oh, the irony) and would probably require a trip to the doctors.

Having said that, oral administration of medicine does have its problems, particularly in relation to the potential attack by acidic gastric juices and enzymes.

Wouldn’t it be wonderful if there was using some kind of material from nature, that we know is very safe, to deliver drugs. Touchingly, Jennie wondered “Can I help the lives of people out there?”

The talk went on to describe the fascinating structure of the outer cell membranes and how they are built with molecules that have one end that is attracted to water and one end that is repelled by water. These align themselves to form a membrane that is two molecules thick, with the water repelling parts of the molecules buried within the wall (see here for nice description). Critically, the cell wall has a number of proteins embedded in its surface. They perform a number of functions, including allowing some molecules to enter the cell.

Jennie went on to describe the “nano-particles” that her research was looking at. These particles are so tiny that, if scaled up to the size of a football, a football would be the size of the earth! Jennie hopes to be able to use these nanoparticles to encase drugs that would not ordinarily be able to survive a trip into the digestive system and allow them to be absorbed by the transporter molecules into the cells and thence into the bloodstream.

A beautiful microscope image was shown of a cell wrapping itself around a nanoparticle, much like ivy wrapping around rock to envelope the particle.

Incidentally, there is a whole area of “Nano Medicine” (see here) and also journals devoted to this topic (e.g. see here)

At this point the reins passed to Eleanor who described the research she was involved in that was looking at targeted therapeutics and also ways of imaging cancerous areas of the body.

When tumours grow rapidly, their blood supply sometimes can’t keep up. This results in the centre of the tumour being starved of oxygen, a state known as hypoxia. Unfortunately, a lack of oxygen significantly degrades the effectiveness of the two main cancer therapies (chemotherapy and radiotherapy).

Work that Eleanor is involved with has resulted in a drug that specifically targets these regions of “hypoxia”

In addition, her research has looked at a technique to finding these areas of hypoxia in the body by MRI (which is relatively common) as opposed to the current technique, PET (which is only available in Manchester and London). Whilst the details of her research remain under wraps until publication of her thesis, it is known that Glucose tagged with radioactive Fluorine18 is taken up by cells but (becaues of the Fluorine) cannot be metabloised and remains trapped in the cell. As cancerous areas take up a lot of glucose, they also take up a lot of the radioactive Fluorine18. Cancerous cells (due to their high rate of cell division) are vulnerable to radiation and are killed by the positron particle released when the radioactive Fluorine decays. You can read more about some work performed on this technique back in 2003 here

Eleanor mentioned, as an aside, that an element called Gadolinium is used as a contrast dye to show up blood vessels during MRI scanning (they are otherwise difficult to see by this technique). NSB, having never heard of Gadolinium before, was convinced that this was a wind up and wondered whether the presenters would try and push their luck by suggesting that the element lay between Gandalfinium and Obiwonkenobium in the Periodic Table.

Upon checking the Internet later, however, it seems that Gandolium is a pukka material (see here) - which just goes to show.

Tuesday, 29 November 2011

Biofuels - The Good



The possibility of using fuels derived from crops and other biological sources - so called "BioFuels" for transport applications is very much in the news at the moment. This three part post aims to have a look at some of the positive and negative aspects of Biofuel production, with a final part asking some questions and trying to put the information gained to some useful use.

This post was initially provoked by a fascinating public lecture at Nottingham University earlier this year. Part of a series of lectures from the Midlands branch of the British Science Association, this particular event was titled "Biofuels - what are they and where are they taking us?" and presented by Dr Roger Ibbett who is a researcher in this area.

Dr Ibbett classified the various Biofuel technologies as being First, Second or Third generation.

First Generation Biofuels are derived from plant materials such as sugar beet, sugar cane, corn starch and wheat starch - i.e. plants that would otherwise be used as food. First generation Biofuel plants are already up and running in the UK, with British Sugar producing 70million litres of ethanol per year from 650,000 tones of sugar beet. A by-product of the process, CO2, is supplied to local greenhouses. One aspect of biofuel production that needs to be borne in mind is that the process of biofuel manufacture itself required energy, and if the amount of energy is too high then the whole process becomes self-defeating. Other biofuel plants in the UK include a Vivergo grain ethanol plant in Hull (420 million litres of bioethanol p.a), an Ensus bioethanol plant in Teeside (400 million litres of bioethanol p.a. - plant not yet operational). Biodiesel plants can also be found at Immingham (300 million litres of biodiesel p.a) and Teeside (375 million litres of biodiesel p.a). A significant fraction of the feedstock for these bio-diesel plants is waste cooking oil. Currently, the UK's transport fuels in the UK are 3.3% renewable.

Second Generation Biofuels are derived from non-food agricultural crops, such as wheat straw, corn stover or willow coppice. It is much harder to convert these to fuels than with the sugary/starchy drops used for First Gen Biofuels. There are currently no second generation biofuel plants in operation in the UK.

Third generation Biofuels are very much at the initial research stage and include technologies such as fuel from algae.

The talk went on to describe how US projections suggested that by 2050 biofuels could, if all planned technologies come on stream, comprise perhaps 10% of the liquid fuels market - and this is a market that will have grown by some 50% in the meantime. So biofuels are clearly not the complete answer, but are part of the solution - in combination with more fuel efficient vehicles, hybrid/electric drivetrains etc.


BFTF certainly found the talk to be food for thought, and did a little research on the Intranet later. This revealed that Brazil and USA accounted for some 88% of world biofuel production in 2010 with the Brazilian bioethanol being produced using state-of-the-art processs with sugar cane as the feedstock. The cane stalks, leaves etc were burnt separately to produce heating. All Brazilian vehicles now run on fuel that contains a minimum of 20% bioethanol (some vehicles run on 100% bioethanol).

A well timed article in the 21May2011 issue of the New Scientist, described for 3rd generation biofuels are attracting serious investment. Exxon-Mobil has committed some $600million to developing algal biofuels with gene sequencing pioneer Craig Ventner while a number of other companies such as Joule Unlimited and LS9 are at the pilot plant stage, with plans for large plants being drawn up for the future.

Taking a somewhat different approach to biofuel generation, Action Aid report that the 30million tonnes of agricultural manure and food waste each year is capable of generating sufficient methane to meet 16% of transport fuel demand, and that so-called "Biogas" fuelled vehicles are becoming widely used in a number of countries, with Germany having installed some 800 gas filling stations by 2008.

On any topic, one source of information that is often overlooked is the government. In the case of biofuels there is something of a "mother lode" of relevant information and consultation at the "gov.uk" website (see link below).

Government Policy and Research on Biofuels

Wikipedia article on BioFuels in Brazil

LACE (lignocellulosic conversion to ethanol) Project

Sustainable Bioenergy Research Centre

Guardian Article on the deforestation caused by biofuels

IEA Biofuels reports

Action Aid list of recent reports

Policy Statement from the Parliamentary Under Secretary of State for Transport

Dr Ibbett can be contacted at: roger.ibbett@nottingham.ac.uk

Biofuels - The Bad



Whilst Part 1 of this post looks at some of the positives of biofuel generation, Part 2 (which you are reading) looks at some of the downsides. . .

One aspect of Biofuel production that needs to be borne in mind is that it can be easy for production of the crop feedstocks to take up land that was previously used to produce crops for food, or to result in clearances of natural forest to make way for feedstock plantations. Occurrences of this latter phenomena have been widely (reported).NSB also found a report from the International Energy Authority (IEA) which, with charming optimism, suggests a "roadmap" that may result in biofuels comprising some 28% of transports liquid fuel needs by 2050.

The 2008 Gallagher report, commissioned by the government, looked specifically at the indirect effects of biofuel production (i.e. if biofuels are grown insted of crops, where are the crops grown?). Although data was limited, the report concluded that "there is a future for a sustainable biofuels industry but that feedstock production must avoid agricultural land that would otherwise be used for food production. This is because the displacement of existing agricultural production, due to biofuel demand, is accelerating land-use change and, if left unchecked, will reduce biodiversity and may even cause greenhouse gas emissions rather than savings."

In order to ensure that biofuels were truly from sustainable sources, Gallagher recommended that the rate of biofuel introduction should be slowed down. Care also needs to be taken with second generation technologies as some of these require larger areas of land to produce a unit of fuel, and thus have an increased risk of displacing food production to land that was previously not cultivated.

Somewhat worryingly, the report mentioned that "feedstock for biofuel occupies just 1% of cropland but the rising world population, changing diets and demand for biofuels are estimated to increase demand for cropland by between 17% and 44% by 2020. However, the balance of evidence indicates there will be sufficient appropriate land available to 2020 to meet this demand." Recognising that sustainability criteria need to be Europe wide, the report recommends that strong, mandatory, sustainability criteria should be included in the 011/2012 EU Renewable Energy Directive

Taking a different perspective, Action Aid argue, that C02 reductions can be achieved in the transport sector without recourse to industrial biofuels. They point out that, amongst other proposed measures, doubling the fuel efficiency of new cars would result in a saving of 12 million tonnes of CO2 emissions per year whilst increasing the percentage of journeys by foot (from 24 to 36%) and bike (1.5 to 15%) would save some 7 million tonnes per year. This is compared to the 2.5million tonnes a year that the current biofuels policy will achieve.

Whilst some of the changes suggested by ActionAid would require significant changes in peoples behaviour (good luck with getting people to leave their cars at home one day a week, for example), the paper does, as mentioned in Part 1 of this post, describe how animal and food wastes could provide very significant amounts of methane (although it is not clear what proportion would be food waste and whether this would be easier or more difficult to collect than the animal waste.)

A bright spot on the horizon mentioned in Part1 of this post was biofuels derived from algae - but even here there are issues. Commercial success is not guaranteed, as shown by the case of US start-up GreenFuels Technologies who went bust in 2008 after difficulties in maintaining its algae growth chambers at its Arizona pilot plant. In addition, there are question marks over whether large industrial plants will show the same performance seen in initial lab and pilot plant trials.

In the UK, the Carbon Trust was funding a "Algae Biofuels challenge" which aimed to "find a winning formula for cultivating 70 billion litres of algae biofuel a year by 2030" - but funding for this has recently been cut completely.

Some reassurance can be found in a statement from Norman Baker, the (deep breath) Parliamentary Under Secretary of State for Transport, who wrote in 2010 that " Biofuels have an important role to play in efforts to tackle climate change, particularly where there is no viable alternative fuel on the horizon, as is the case with aviation and HGVs. In addition, they also have a role to play in promoting the security of energy supply. But we firmly believe that the
potential carbon benefits of biofuels can only be realised if they are produced in a sustainable way", going on to say "In particular, my Department takes the issue of indirect land use change seriously. . . I have written to the EU Energy, Environment and Climate Commissioners to impress on them the need for an
adequate and robust solution".

So there you have it. It's complicated. This post has only been able to scratch at the surface of just a few of the issues involved.

Government Policy and Research on Biofuels

Wikipedia article on BioFuels in Brazil

LACE (lignocellulosic conversion to ethanol) Project

Sustainable Bioenergy Research Centre

Guardian Article on the deforestation caused by biofuels

IEA Biofuels reports

Action Aid list of recent reports

Policy Statement from the Parliamentary Under Secretary of State for Transport

Dr Ibbett can be contacted at: roger.ibbett@nottingham.ac.uk

University of Nottingham Mayfest

Universities have long had "Open Days" for propsective students, but having such events for the local population is a much more recent, and very welcome, phenomenon.

Nottingham University had their first open day for the community in 2009. The success of this initial event resulted in a bigger and better open day in 2010 and then in this years extravaganza called "Mayfest".

[See also 2012 May Fest (with pictures) and 2013 May Fest (with pictures)]

A free, day-long occasion held on May 7th, Mayfest is perhaps best descibed in the words of the programme - "Old favourites return to sit alongside many exciting new activities. The fantastically popular 'Thunder and Lightning' sessions are back, you can find out what it takes to be a vet, try some brain games or chat with scientists in the labs about the world-leading research being carried out on your
doorstep. Or you could explore our campus with a tour of the secret gardens. We’re a major employer in the region, so you’ll also be able to find out about opportunities to work or study here."

The programme goes on to give a comprehensive listing of all the events taking place which cover subjects as diverse as archaeology, astronomy, biology, geography, physics and eco-housing !

Having been to the (much smaller) 2009 event and enjoyed it tremendously, Nottingham Science Blog (NSB) was very excited about the 2011 gig and found that, quite simply, there was not enough time in the day to fit in all the stuff that there was to do and see. The wee ones also really enjoyed the event, especially the "Thunder and lightning" demonstration. . .

Now, if you only remember one thing about science lessons at school it is likely to be the experiment where the teacher showed what happens when lithinum is put in water, or the one where mangnesium reacts with a ferocious white flame to form magnesium oxide. Well, in "Thunder and Lightning" they took it to the next level. High points included the spectacular ammonium dichromate "Volcano reaction" (the clue is in the name) in which the amount of material present after the reaction seemed to be a lot more than there was before it; the rather loud "Barking Dog" reactions that demonstrated how flame fronts propagate and a series of demonstrations of the chemistry of some explosive compounds. This latter part of the programme included firing a wax candle from a breech loading musket through three layers of plywood and also a demonstrantion on how small amounts of explosive can bend metal plates (and make a bang so loud that it will leave your ears ringing ! Utterly top quality stuff- guaranteed to make science seen interesting and exciting. NSB will certainly be there next year.

Later, in the physics department, NSB was able to see the Universities telescopes and see live images of sunspots on the. . .er. . .sun. Also, a range of experiments and demonstrations were on show, including a desktop microscope that can resolve down the atomic level (let me say that again - it can see individual atoms!!!) and experiments involving liquid nitrogen (there seems to be no limit to the fun that can be had with this cryogenic material).

Moving to the Portland Building, where further activites were on show, BFTF was able to "fly" around a 3-D model of the lake disrict in the geography section, move a ball through the power of thought alone in the biology section and talk to a researcher from the "science and society" department about the assessing the risks of introducing new technologies.

This last point touches on something that is a wonderful feature of open days such as Mayfest - you can talk to the researchers and students who are working in these specialised fields. Now, it is certainly the case that students are called students for a reason, and it is remarkably easy to trip them up by asking the most innocent of questions. Most memorably in Mayfest 2011, asking a physics student about how light rays in a fibre optic cable "knew" whether to bounce off or go through the outer wall of the fibre resulted in the student saying that this was a very good question and that he would need to find out the answer in the library that night!). In contrast, talking to the senior researchers is rarely anything other than a fascinating learning experience that brings the opportunity to see many aspects of a field that the mainstream media simply does not report.

Sadly, as mentioned earlier, there simply was not time to see everything, so NSB missed out on the chance to see how Nottingham Universtity is a Human Rights Hub, any of the Engineering displays, the interactive poetry areas, the Philosophy section, the Archaeology section. . .well, I think you get the picture.

The event was certainly very well attended, by both parents and children alike and numbers did not noticeably drop until the University staff started packing up at about 5pm.

It is worth mentioning that Nottingham University (as is the case with many other Universities) has a calendar of public lectures on various topics. These are a great way of learning about a field of study from an expert in the area. There is always a question and answer session, so you can quiz the presenter if you feel that they are missing a trick or if you want to clarify a point.

One need not feel restricted to lectures in a subject that you are knowledgeable about, public lectures are a great opportunity to find out more about topics that are in the news (for instance Nottingham

University has just had a public lecture on "European Politics in 90 minutes") or are simply interesting (such as another recent lecture entitled "Why do chemists want to make new molecules")

These lectures are, in NSB's experience, invariably a great learning experience, and offer a chance to hear about topics from experts in their field without the distorting lens of the media gettting in the way.

For parents, particularly those of children in secondary school (and if you the youngsters are interested), public lectures provide an opportunity and reason to actually visit a University and to see what the buildings and lecture theatres are like. This can only help break down any fears a youngster may have about higher education. Also they get a chance to see, at first hand, the enthusiasm of researchers and the kind of teamwork that is characteristic of research activities. It is a real eye opener to hear the efforts that people go to in order to find answers to the questions they are puzzling over.

So there you go. University Public Open Days and Public Lectures. Its all Good.

Find out about the actions that this event provoked in part two of this posting - here.


Further infornation:
University of Nottingham Mayfest
University of Nottingham Institute for Science and Society
University of Nottingham Community Engagement

The First Post

Science, Engineering and Technology.

Three subjects that just don't seem to get the coverage they deserve in Nottingham.

Let's see if we can't put that right. . .