Half Baked. Interesting comment from Sebastian at Onfolio about scientists not being up to speed with syndicated news content. It occurred to me that one area in which it might be incredibly powerful for active scientists is in the preprint arena. They could release their up-coming papers and posters using a newsfeed and by providing comments space on the paper’s web page get instantaneous feedback to help them fine-tune their paper before submission to their favourite scientific journal.
Category: Technology
Tech Talk – Miscellaneous discussion of gadgets, industry, computer science, social media, AI
Bright, young and photogenic
Having a quiet beer in Cambridge with friends yesterday evening our peaceful drinking session was disrupted by the arrival of a boisterous group of snap-happy first-year students. Eager to impress these bright young things, my friend Paul offered to take a couple of photos of the whole group, but came unstuck when attempting to grab the second snap.
Fortunately, one of the freshers pointed out that the camera needed “winding on” and all was well.
But, it got us thinking…winding on..? Wasn’t this Cambridge, international centre of academic excellence at the heart of the so-called Silicon Fen high-tech industry?
Maybe, given the number in their crowd wearing tweed jackets and the like it wouldn’t have been any more surprising if they’d been using a Box Brownie.
Telesales Revelations
A British telesales company recently sent off its workers’ computer keyboards for analysis to a nutrition expert to find out exactly what its staff were doing at their desks in terms of eating habits. Unsurprisingly, the analysis of the detritus stuck in and among their keys revealed that most staff were snacking heavily on sandwiches, cakes, pasties and the like while working at their desk. Splashes of tea and coffee were also commonly observed. Fragments of crisps, grains of sugar and nail clippings (toe and finger!) too emerged from within many of the keyboards after a good shake.
But, never mind the snacking and personal grooming. A male pubic hair found stuck under one worker’s "ESC" key has not yet led to a dismissal. The company, however, is planning to move to an open plan office rather than its current cubicle-based layout to reduce the alleged, ahem, "time-wasting" that was presumably underway in at least one workstation prior to the analysis.
Scholarly Google
Google is just so active these days what with its desktop search tool, the beta of Google Groups 2, and now something specifically for academic-type research – Google Scholar – a scholarly Google in other words. It looks at first glance rather promising, being potentially a replacement or a complement to Elsevier’s Scirus…but, you’ll notice my carefully worded description "academic-type". It seems that a lot of early adopters are already finding the fatal flaws in its results, so if you were looking for a serious web research tool for science this is probably just one to add to the arsenal rather than being the weapon of mass deduction you were after.
Post note: Moreover, although this is a scholarly Google, there are a growing number of scientific tools online now that circumvent the need for such an academic search engine. With the advent of Connotea, ChemRank, and ChemRefer, and other such wonders, finding scholarly information is almost a cinch.
Green silicon production
Making the electronics industry green
A new electrochemical process for silicon extraction could make large-scale production of this widely used material more environment friendly, according to chemists in China.
Silicon has an essential role in the world of electronics, being familiar in countless components from microelectronic silicon chips and optical fibres to large solar panels. It is also employed in the production of silicones, which are used in everything from bathroom sealant to cosmetic augmentation materials. Silicon even finds a role in alloy production.
Industry generally uses a straightforward reduction method to produce elemental silicon starting with silicon dioxide (SiO2 in the form of quartz). Carbon is the reductant and the process is carried out at 1700 Celsius. Carbon dioxide is the by-product as oxygen is released from the silica. According to Nottingham University’s George Chen currently a Specially Invited Professor in the College of Chemistry and Molecular Science at the Wuhan University in China, this process was used to produce about 4.1 million tonnes of silicon world-wide in 2002, with a corresponding release of 6.5 million tonnes of the greenhouse gas carbon dioxide into the atmosphere.
Chen and his colleagues, Xianbo Jin, Pei Gao, Dihua Wang, and Xiaohong Hu, believe that a more environment friendly approach should be attainable using electrochemical reduction rather than the conventional energy-hungry carbothermal process. “The old-fashioned charcoal technology should be replaced by a more advanced process from the environmentalist viewpoint,” the researchers say.
Electrolytic production of silicon was first carried out as long ago as 1854 by French chemist Etienne Henri Sainte-Claire Deville (1818-1881). A purity level of 99.999% has since been claimed by GM Rao and colleagues using fluorosilicates in a molten fluoride. In the early 1980s, however, results began to suggest that silica would be the ideal raw material, but high temperatures would be needed to make these processes work. The Wuhan researchers have now revealed a new electrochemical technique, which they claim will become viable for the large-scale production of silicon, because it avoids the high energy costs and reduces the carbon dioxide emissions considerably.
For the electrochemical extraction of silicon, Chen and his team took the approach of using silicon dioxide itself as the material for the negative electrode (cathode). They also opted to use molten calcium chloride as the best electrolyte for the job. Calcium chloride is well known as an electrolyte for electrochemical reduction of metal oxides at high temperatures. Sharp-eyed readers will have spotted the potential flaw in their arrangement, however. Silicon dioxide is, of course, an electrical insulator. Nevertheless, the researchers persisted with their idea and found in initial tests that conversion of quartz to elemental silicon does in fact occur at the three-phase boundary between the silicon dioxide, the electrolyte, and the flattened end of the tungsten wire that is used to connect the electrode to the circuit. This provides enough impetus for the electrochemistry to kick in properly as the silica is gradually converted to conducting silicon.
Theoretically, says the team, the reaction should eat its way through the entire silica electrode. However, the researchers found that in practice only a small area around the tungsten plate is in fact converted. They explain this in terms of the physical characteristics of the electrolytic melt – it simply cannot penetrate sufficiently deeply into the newly formed silicon layer on the surface of the silica electrode. This has the inhibiting effect of preventing further formation of the three-phase boundary and so the electrochemical reaction grinds to a halt.
Determined to make the process work though, Chen and his co-workers have now found a practical solution. Instead of using a solid quartz electrode, they have switched this for silicon dioxide powder that has been pressed into thin pellets and then sintered. The resulting electrode is, of course, then porous enough to allow the electrolytic melt to penetrate more deeply into the material of the electrode. Indeed, the particles, just a few micrometers across, are much more effectively converted to silicon powder by the electrolysis process than in the solid silica electrode. The use of X-ray diffraction provided the researchers with assurance of the purity of the silicon they were producing.
In terms of industrial application, high purity, low-energy, and reduced carbon dioxide emissions will all be rather desirable properties of the new silicon-production process. Moreover, as bulk quartz would not be practicable for industrial production, the discovery that silica powder, which is far more readily available, works with this degree of success is much more likely to be make the process attractive to silicon manufacturers.
In addition, the researchers discovered that by mixing the quartz powder with other metal-oxide powders it is possible to directly produce fine-tuned alloys using their electrochemical reduction method. Fine powders of oxides can be prepared easily and mixed uniformly, the researchers explain, so that the electroreduction of such mixtures leads to an alloy, the composition of which is precisely controlled. They have successfully produced Si-Fe and Si-Cr alloy powders with a particle size of 2-3 mm in this way.
Despite the long history of silica electrolysis dating back to the mid-nineteenth century, Chen and his colleagues have demonstrated, for the first time, that porous pellets of silica powder or mixtures with other metal oxide powders can be electroreduced to pure silicon or its alloy in molten calcium chloride. Their cyclic voltammetry studies revealed that electroreduction can proceed very quickly indeed, although perhaps at higher current densities than would be viable on the industrial scale. Nevertheless, the CV studies will provide developers with a fundamental reference against which to match the design of a true industrial process for the mass production of silicon powder by electrolysis. Usefully, as reduction depth and time follow an approximate logarithmic law, this can be used to select for a particular particle size too adding to the versatility of the process.
At the time of writing, the team was optimising their electrolysis process.
Further reading
Electrochemical Preparation of Silicon and Its Alloys from Solid Oxides in Molten Calcium Chloride. Xianbo Jin, Pei Gao, Dihua Wang, Xiaohong Hu, and George Z. Chen. Angew. Chem. Int. Ed. 2004, 43, 733-736
New Spin on Electronics
At the borders between physics, chemistry, materials science and electrical engineering, is where some of the most exciting technological developments take place. Think polymer light-emitting diodes, porous silicon explosives and now spintronics.
Denis Greig and Robert Cywinski at Leeds University are working with colleagues at the Universities of Salford and York to grow ultra-thin magnetic films on semiconducting materials and to characterise their surface chemistry. Spotting dead layers with no magnetism in the surface atomic layers of such material composites will be important in controlling the spin properties of the material in the bulk.
Oxide magnets such as CrO2La1-xCaxMnO3, Fe3O4 and the Heusler alloy NiMnSb are being developed by Lesley Cohen (http://www.ph.ic.ac.uk/staffcv/cohen.htm) and Tony Stradling (http://www.ph.ic.ac.uk/staffcv/stradling.htm) of Imperial College with European Union funding. They reckon these materials will make excellent sources of spin-polarized currents. They are trying to grow such “half metallic ferromagnets” on high-quality semiconductor layers, such as indium arsenide. The ultimate aim being to fabricate to fabricate spin transistors and highly sensitive magnetic sensors.
“A huge effort is being generated world wide in this area,” explains Stradling. This is mainly driven by the putative link between spintronics and quantum computing, which once researchers get it to work will provide much faster information processing than is presently possible. Much of the spintronics work is going on in many UK physics departments, such as Bath, Bristol, Cambridge, Glasgow, Heriot-Watt, Nottingham, Oxford, St Andrews, Salford, Southampton, and York.
Such efforts are at the centre of worldwide multidisciplinary efforts to add another dimension of control to electronics and bring us into the realm of spintronic devices. Physicists are still just learning how to control the spins of electrons to allow them to align them on the fly in materials being created to exploit their properties in new computers, sensors, and other devices. Materials designed to exploit the spin of the electron are beginning to emerge. The only spintronic device which is presently being used in real systems though is the two-terminal GMR type of sensor . But, spintronics has potential in fields as diverse as position and motion sensors for robots, fuel-handling systems for vehicles and chemical plants, military guidance systems, and even the next generation of keyhole surgery techniques.
The mobile phone hanging on your belt, the motherboard in your PC, or the amplifier in your portable MP3 player all use charge carriers to transport information in semiconductor materials such as silicon. But, charge is not the only intrinsic property of the electron, in common with certain other sub-atomic particles, the electron also has spin.
The spin of an electron is not like the spin of a pool ball though. Rotate a pool ball through 360 degrees and you get it back to where you started. If you can see the “8” and you rotate that ball 360 degrees you will see it come around again. If an electron could be marked in some way, you would have to rotate it through 720 degrees before you saw the marker again. It takes two full turns for an electron to “spin” once. This bizarre quantum property is not at all far-fetched, one just has to remember that an electron is not a tiny pool ball, but a sub-atomic entity closer to a notional Möbius strip than a sphere. Anyway, I digress. Electron spin, can be up or down, and this property will be used to develop spintronic devices that are smaller, more versatile and more robust than any conventional microelectronic circuit.
It is the alignment of electron spin that gives rise to the bulk magnetic properties of a metal such as iron or cobalt. If the bulk of the electrons in a piece of iron are either up or down then the iron is magnetised. The magnetic state of an iron particle can be written and read – viz. magnetic data storage, from tape to disk. The state is represented by the orientation of the iron’s magnetic moment.
But, rather than looking at the properties of chunks of iron, what if we consider the more subtle effects seen with a sandwich of very thin layers of material – the outside layers might be cobalt or another magnetic material while the innards would be non-magnetic. The magnetic layers have their electrons either all up or all down as usual. But, because of the thinness of the layers electrons with the same spin can pass through the non-magnetic layer while those of opposite spin are deflected, or scattered back. Because of this the sandwich acts as a filter for either up or down electrons depending on the nature of the magnetic layers.
At this level one begins to see a much stronger effect – the “giant magnetoresistance” (GMR) effect, which relies on this filtering of electron spins across the layers. The effect, an increase in resistance due to the presence of a magnetic field, is 200 times greater than seen with common magnetoresistance and provides the basis of the read head in multi-gigabyte computer hard disks pioneered by IBM.
It is of course possible to change the orientation of the spins of the electrons in each layer so that they can be made the same or opposite, in this way the number of electrons that are scattered back can be changed. A device that functions in this way has been referred to as a spin valve because it can be used to inhibit or open up current flow. Any device acting as a valve can be considered a switch, and a switch to a computer designer means logical unit or memory bit. Simply flipping the orientation of spin in one layer changes the spin valve from a 0 setting to a 1 setting and so forms the basis of a new magnetic version of random access memory (RAM). Importantly, MRAM is non-volatile. Switch off the power on your computer now and you’ll lose everything in memory. Not so with MRAM, what is written to memory stays there until it is deliberately wiped. Some observers caution that while this is true in that it has indeed been proposed it has yet to be shown that GMR RAM chips are a viable technology; remember magnetic bubble memory? No?
Quite.
However, we already have GMR read heads – to read high density media – although increasing data density is still a major aim of IBM and other manufacturers, while developments in the preparative methods of insulating metal oxide layers and other materials are making for rapid progress in MRAM. Other devices are beginning to emerge with the development of controllable spin transistors and the like as magnetic semiconductors and other oxides are designed with greater magnetoresistance and spintronics effects. The silicon age is not quite passé, it will be with us a long while yet, but there is a new spin on electronics.
The old ones are the best
An apocryphal story was doing the rounds of the chemistry discussion groups on the internet a while ago. You can substitute your own alma mater and personal weekend hobby for greater comic effect when relating the tale.
Two undergraduate chemists at Newcastle University did very well in their mid-term exams, their practical results were squeaky clean – both were headed for a first. In fact, the two friends were so certain of their chances they spent the weekend before the crucial final fell walking and partying at a hill-top youth hostel.
Either suffering from all the fresh air or one or two more beers than they should have had on the Sunday night they didn’t make it back to Newcastle until early Monday morning. Rather than taking the crucial final they spoke to Professor Bunsen after the exam and explained that their car got a flat tyre on the way back to University and the spare was dud.
Bunsen was a lenient chap and agreed they could take the exam the following day. The friends were so relieved and studied hard that night. For the exam they were put in separate rooms and given the question booklet. Question One was a simple test of chemical reactions (5 points) and each thought the exam was going to be easy. They were unprepared, however, for what they saw on the next page. It said: “Which tyre? (95 points)”.
Wireless power
Cambridge start up Splashpower hopes to commercialize wireless power technology for recharging all your rechargeable devices, cellphones, mp3 players etc, without having to worry about plugging different chargers into power outlets.
Their approach has two parts: the first is a sub-millimeter thin receiver module that can be customized to just about any size, shape or curve of a device. The second part is a thin pad (less than 6 mm) that acts as a universal wireless charging platform and is plugged into the power outlet. Any device fitted with a SplashModule instantly begins to recharge when placed anywhere on the pad.Several devices can be charged at the same time.
Major benefit cited by the company include:
- Contactless, efficient, wire-free power
- Fast and safe charging rates
- Low-cost technology
- Low profile
Caps in hand
A recent announcement from The Scientific World website has the chemical information discussion group CHMINF in something of a panic. Apparently, the medical database MEDLINE is to abstract the Scientific World journal. But how will it be referenced the chemical informaticians wonder. The official name is “TheScientificWorldJOURNAL”. And, yes, all those capital letters really should be there. CHMINF’ers worry that the abstractors will create a whole range of variations on this theme in typing up their abstracts, which means the journal might be listed under several different entries, such as Scientificworldjournal, TheScientificWorldJournal etc. and this could have enormous repercussions for getting to the facts. Or, maybe not. The real chance for panic was brought to light by Wendy Warr of www.Warr.com. She points out that there are probably countless mistyped references to systems such as Cerius-squared and RS-cubed, “STN Express with Discover!” with its bizarre exclamation mark and the word Discover in italics, and even the Royal Society of Chemistry’s “chemsoc”, which must never start with a capital “C”. Then there are molFile, MolFile, and molfile, ISIS/Base (no dash just a slash), ChemWeb and chemweb, and even SCIENCEbase.com, or is it Sciencebase.com?
Google agog
We were searching for a mugshot of a medical scientist to illustrate a news story but Google’s image browser failed us in our quest. Until, that is, we switched “off” the Adult Content filter employed by the search engine.
At this point our elusive scientist appeared together with pictures of the covers of the journals Science, Nature, PNAS, and Neuron. Now, what was it about our scientist contact that meant he was X-rated and what was it about those journals that they were considered by Google to be adults only? Should librarians be putting them on the top shelf? One possible explanation is that Google filtered because the cover pictures of the journals were on the University of California’s Anatomy Department website.
So, the reasoning goes, “anatomy” must be too salacious for Google hence it was filtered. Just think what else you might be missing in your image searches. Incidentally, his research is in the totally unsalacious field of TB.