SciencePod — Waste Not Want Not


Photo Credit: Eindhoven University of Technology/Bart van Overbeeke

This week, we

follow up the feasibility of some fuel-filled trees from a previous episode, and explore the wonderful world of plastic electronics. The article discussed today was first found on Eurekalert. If you have found this episode at all interesting, please do me a favour and leave a comment or rating either here or at the iTunes subscription page. I’m enjoying making these, but I’d love to know if they’re interesting to people other than myself. :) As per usual, the transcript and some links follow the jump.


The original article on Eurekalert.

A more in-depth look at the new study on biofuel land availability.

The food standards website that talks about ‘best before’ and ‘due by’ dates.

The page for the Nobel prize awarded for conductive polymers.


Hello and welcome to another episode of the Tooth Soup Science Pod. On this week’s epsiode I’ll be revisiting some of the research from a previous episode with some new perspectives, and then discussing some research that might send ‘best before’s out of date.

But first, to the follow-up. In the 3rd episode of the pod, I talked about the simple yet effective technique of tilting willow plants on a diagonal to get them to produce more biofuel. I really love research like that which shows an obvious kind of clear, logical thinking that leads to a result. You may recall though that at the end of the podcast, I was a bit reticent to call it a revolution in biofuel. Let’s do a flashback to hear me be all sceptical:

Of course, in the grand scheme of things, there’s more to think about than just how much energy we can get out of a crop. If biofuel does become a major source of energy in the future, its need will have to be weighed against the same land being used for agriculture.

Well, it seems like a few other scientists have been thinking the same thing. Steffen Fritz and his colleagues from the IIASA, that is, the International Institute for Applied Systems Analysis, have re-analysed the amount of land that might be considered suitable for biofuel crops. As opposed to previous estimates of between 320 to 1411 million hectares being good to go for biofuel, their results have shown that there is as little as 56 to 1035 million hectares. That’s quite a dip in the range. But it’s not only the new numbers that interested me in this story, it’s the way that Fritz and co. managed to get them. They funded and ran a ‘citizen science’ program that had volunteers from all around the world categorizing snapshots from Google Maps as being unsuitable or suitable for biofuel. So if say, there was forest in the snapshot, or the land was obviously being used by humans, the volunteer citizen scientist would click it as being unsuitable and move onto the next image. In this way, they were able to classify roughly 20,000 locations multiple times to ensure reproducability, and therefore adjust the estimates down. Crowdsourcing science is a relatively new tool in the researcher’s utility belt, and it’s great to see it being used to help solve some of our most pressing environmental issues. Anyway, the question still remains as to what the cost/benefit analysis of fuel versus food will end up being, but my bet would be on filling the dinner table winning out as the most important use of our arable land.

Speaking of food, if you’re anything like my girlfriend you will be very familiar with the machine-typed black lettering that adorns nearly every single food package in your pantry. The ubiquitous ‘best before’ date is to her a chronological switch that, once flicked, means that whatever is in the package is irretrievably ‘off’. But she’s certainly not alone in this thinking, every year it’s estimated that million of tonnes of food are thrown away as a result of folks being ultra-conservative with their food and the risk of eating something that has gone rotten. Before I go any further, I’m just going to read out a couple of sentences from the official Australian Food Standards website with regards to the labelling of foods:

You can still eat foods for a while after the best before date as they should be safe but they may have lost some quality. Foods that have a best before date can legally be sold after that date provided the food is fit for human consumption.

Foods that must be eaten before a certain time for health or safety reasons should be marked with a use by date. Foods should not be eaten after the use by date and can’t legally be sold after this date because they may pose a health or safety risk.

So it’s pretty much the case that the ‘use by’ date is like getting to a job interview; you want to be there a bit early to make sure. Whereas the best ‘before’ date is like one of those annoying Occupational Health and Safety meetings once you’ve got said job; you can miss it, but you’re taking a slight risk of future harm.

Whether you’re a suspicious snacker or more lax with your lunch’s due date, it would be useful to know exactly how long food has left before it actually spoils. And that’s where this week’s new research steps in. As with most scientific endeavours, it’s a combined effort by researchers out of the Eindhoven University of Technology in the Netherlands, Universita di Catania in Italy, the Laboratory for Innovation in New Energy Technologies and Nanomaterials at the Atomic Energy and Alternative Energies Commission in France, and a private company called STMicroelectronics. The invention itself concerns producing cheaper electronics by making them out of plastic, rather than silicon.

The idea of making plastic electronics isn’t a new one. A nobel prize was even awarded for the discovery and development of a type of material called a ‘conductive polymer’, which is like a plastic that can conduct electricity. The advantage of these conductive polymers is that they are flexible, light-weight, and can be printed using fairly low tech such as an inkjet printer or even screen printing. However, at the moment the printing process is still being optimised, with a number of challenges remaining before a reproducible high quality is achieved. But once these challenges have been met, we’re going to want to have a bunch of electrical circuits already figured out so that we can start printing them en masse, and that’s what the researchers in this study are out to do; create printed circuits out of plastic that can be ready for when the manufacturers have ironed out all their bugs.

The circuit that they’ve managed to figure out how to print in this study is called an ADC: analog to digital converters. What this means is that a completely plastic circuit can now take a signal, say the acidity in food, and convert it into a display that tells folks whether or not the food has spoiled yet. It’s worth mentioning that we could probably do this already with standard silicon circuitry, but it would be far too expensive for manufacturers to take on; around ten cents per item, and that eats into profits. Using the future printing press of plastic electronics, the researchers estimate that it could cost less than a cent to produce a plastic circuit that could tell shoppers what’s fresh and what’s not. Economies of scale often take a front seat in scientific discoveries such as this one, where the future application is at the forefront of why the research is being undertaken. Aside from telling the freshness of food, the researchers say that plastic circuits might also see applications in pharmaceuticals, man-machine interfaces, and ambient intelligent systems in buildings; I’m not entirely sure what that last one is about, but it sounds pretty speccy. As far as a timescale goes, the scientists are estimating around five years before we see real-time best before circuits on our food packaging. And if it helps people to stop throwing out perfectly good food, I’m crossing my fingers that it it won’t be even that long.

Anyway, that’s it for me for this week. Feel free to subscribe at the iTunes page and leave a comment and a rating while you’re there. As usual, there will be links ot articles I’ve read and a transcript of the show on my blog page. Thanks for listening, until next time.


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  1. My housemate is incredibly strict on “Best Before” dates, to the point where I would normally be frustrated; if it were not for the fact that one day he made me a cup of coffee with milk that was one day past the printed date. The salty, bitter, lumpy beverage was immediately poured down the sink, and my convulsing stomach ended up struggling to keep breakfast down. (I should point out that he didn’t serve me off milk on purpose, it was a genuine mistake)

    Now I am a little more zealous than I used to be.

    • With milk and dairy I think the due date on milk is definitely one to be obeyed; nothing like lumpy coffee to make you check each carton with suspicion before pouring it out. ;P

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