An even better SA I&C!
Regular readers of SA I&C will notice something different about the look of the magazine. Our publisher (ever-looking for ways to make the magazine read better) tasked the artists to create a design that carries our regular editorial features more coherently. Personally, I think it looks terrific. It is a bit more work - but we think it is worth it. Have a quick flip through pages - see what you think.
Energy supply technology
IOL ran an article entitled 'SA may become the powerhouse of the world' which told of how much research is being conducted in the field of commercial hydrogen fuel-cell technology. The beauty of such technology is that the 'exhaust' of such fuel cells is plain water.
Before everybody gets too excited, the energy needed to separate hydrogen to make it available for consumption is naturally greater than the energy that is to be had by burning it, or combining it with oxygen in a fuel cell - so all this energy must come from somewhere, be it oil, coal, natural gas, hydroelectric, nuclear...
IOL's article continued, telling us that vehicles using this technology are likely to land in American showrooms before 2006. Big deal, you think - but it so happens that these fuel cells need something that SA has more of than any other country... platinum. As fuel cell production increases (which the steadily tightening emission restrictions will likely enforce) the demand for platinum will leap through the roof.
This 'platinum rush', together with the superb energy position of South Africa (as discussed by Maurice McDowell in 'What effect would the looming world fuel shortage have on the I&C industry? Part two - Opportunities for the local I&C industry) puts us (South Africa) in what may appear to be a very good position, especially for the I&C industry involved in mining and energy... So industry looks good - but how do big, powerful, power-hungry countries treat smaller countries with such juicy fare?
Aerogels in analytical instrumentation
In keeping with our laboratory equipment feature ('Total organic carbon (TOC) analysers)) I thought it would be good to revisit aerogels. Readers may recall these wondrous substances, which I introduced in the March 2004 issue. The lightest known solids (around four times the density of air) aerogels look like solid smoke. It turns out that their optical transparency; high surface area, the ease with which gases diffuse via their pores, their thermal and chemical stability, and ability to be filled with additional active phases, make aerogels useful for sensor applications.
The Microstructured Materials Group discovered a process that results in a permanent visible photoluminescence in silica aerogels. After appropriate preparation, the intensity of the photoluminescence has been seen to be indirectly proportional to the amount of gaseous oxygen within the aerogel.
Advantages of using an aerogel-based sensor element include a rapid response time (due to rapid diffusion of gases through the aerogel's extensive pores), and improved resistance to photo-bleaching (as the photoluminescence is caused by stable defect centres in SiO2). The Microstructured Materials Group has built a prototype oxygen sensor based on this technology. It seems that the device provides a cost-effective means of monitoring oxygen concentration up to 30%, with moderate sensitivity. The sensor has been observed to operate undeterred by other gases present in the feed gas and looks set to operate over a temperature range that may exceed the initial -25 to +85°C (which was limited by the system in use). The devices exhibit increased sensitivity at the lower temperatures.
It would be interesting to know if there are any among our local instrumentation developers working on competitive South African versions. Those interested can find out more from: http://eetd.lbl.gov/ECS/aerogels/sao2sens.htm
John Gibbs - Editor
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Past articles can be found at www.instrumentation.co.za
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