This is a quick guide to making metal foams - mostly aluminium foams. It's drawn from one of the introduction chapters of my 2004 PhD thesis (the full version, with sources and experimental processes, is free to download here ). There are lots of different ways of making foams, with different levels of complexity. Aluminium is the most commonly made foam, because it's light and easy to work with - though some of these processes can work with other metals. This summary looks at a huge range of 'metal foams'. When thinking about ways to make a foam there's a lot to consider:
Conscious that this has become a little hard to find online, I thought it'd be worth posting a link to my PhD thesis, Production of Aluminium Foam using Calcium Carbonate as a Foaming Agent , from the Cambridge years, online. Because research is frankly no use unless people can access and build on it, and there's a fair bit in here about aluminium foams that's still interesting and relevant. This was the first time that anyone had spent any real time looking into calcium carbonate as a way of making foams, and to cut a long story short it turned out to be a very cheap and cost effective way of doing it - because the gas produced was (oxidising) carbon dioxide rather than the more widely used (reducing) hydrogen gas, it made a thin layer of alumina on the aluminium cell walls and in doing so hugely stabilised the molten foam. This transformed what had previously been a pretty unstable production process, and meant that foams could be made on a far more industrial ba
Way back, I decided to plot out and lead a walk - for wither the Metropolitan Walkers or the Capital Walkers - which was of a sort of medium length, and with some of the useless London urban trivia that I know far too much of. Quite some time passed, but at last - here it is! A relaxed walk south of the river, generally avoiding the tourist trail and stopping to see some of the, ahem, "lesser-known landmarks" of the area, which is a sort of code for the kind of thing I find interesting and pretty much no-one else does. It includes a short ferry trip to get across the river to Canary Wharf the river at the end of the walk . In case anyone wants to try it at any other time, the full & zoomable / printable version of the images below, which are designed as a sort of 'interesting features' flyer, is here on Google Photos . The walk's just under 8 miles long, and includes an interesting couple of pubs in the quieter second half (East of London Bridge). 20
London has dozens of Angus Steak Houses and near-identical (apart from the name) Aberdeen Steak Houses, as well as the odd American Steak House. It's not unusual to see several branches within sight of each other - indeed at one point there were three on Shaftesbury Avenue, two of which were directly opposite each other. They have a curious history, which all started in a chance encounter when butcher Reginald Eastwood met accountant Tom Beale and bar-owner Peter Evans, whose bar The Cat's Whisker on Kingly Street in Soho had just been closed down by police due to overcrowding. With one eye on American chop houses, and the other on the increasing disposable income of Londoners - especially those out to see shows in the West End - they spent just a few weeks converting the premises into the first Angus Steak House, selling "supremely succulent Scotch steaks" at "prices that won't spoil your appetite" - and went on to develop 40-odd restaurants in i
Anyone who's driven along Switzerland's main East-West motorway near Martigny will have seen the rare experimental wind turbine in this photo. It's a Darrieus vertical axis turbine, and has been there since 1987. It was hugely experimental at the time, and I believe there's even some complicated connection with the adjacent sewage works and biogas plant (which is also quite innovative), though - possibly as its main use was well before the web kicked off - there's precious little about it online. It's in one of Switzerland's windiest valleys - but the most famous feature of this turbine is that it's hardly ever rotating. I think I've only ever seen it in action twice. It was also taken down at various points in its lifetime - sometimes for several years; indeed on Google Maps' aerial photo ( here ) you can see it lying down - but now it's back up. This old and now largely abandoned turbine is all that remains of an alternative future
Google Maps doesn't always get the destination right first time. And just occasionally, you stumble across something genuinely strange in the process. Take Port Charlotte in Florida, which I arrived at by accident. Miles, and miles, of roads laid out - but no houses. A closer inspection shows that these roads are not new, and there's no sign of any building or development going on. There is a small city centre - but these empty suburbs surround it in all directions and cover more than five times the total surface area of the populated town.
A guide to meanings of common chemical safety/hazard symbols (a.k.a. warning labels, Danger symbols, Chemical safety labels...). These are the European/international standard; I originally put them online as they didn't seem to be anywhere else; they seem to still be popular judging by the number of people who read this so I've carried them over to blogger as a bit of a public service... Click on the images to enlarge , for printable label size and suitable for downloading. Feel free to use these pictures. Poisonous The poison symbol is self-explanatory. Whereas most chemicals are fairly dangerous if ingested or inhaled, many of these are dangerous even on contact. Environmental hazard Relatively rare with laboratory chemicals (most of which pose some environmental hazard if not got rid of correctly), these require particular care to be taken on disposal. Corrosive Will destroy or irreversibly damage another substance with which it comes in contac
Back when I lived in North Battersea, I grew a bit curious about an old (and rather run down) church, lost in a tangle of industrial units and light warehousing in the unfashionable bit of Battersea. As a bit of out-of-place Victoriana it was a bit of an architectural curiosity, that seemed to have survived long after all its neighbours were bombed, demolished or redeveloped between the 1940s and 1980s. Caius House (variously known as Caius House, Caius Mission, Caius House Church and Caius College Mission Church) was on Holman Road in Battersea.
A very old guide to punting from Cambridge to Grantchester - picking out some of the highlights. Not especially useful but it seemed a shame to lose it. The Punt Pool All punt trips using St John's college punts start (and hopefully end) here. Note the swan nest on the island in the spring (sometimes populated with rare black swans, imported from New Zealand and only usually seen in St James' park in London). The Bin Brook A little-known tributary of the River Cam; it is shallow and muddy. It has been known for Johnians and lost tourists to punt down here. That said, it isn't exactly one of the highlights of Cambridge. Downstream You can't go much further than Jesus Green without permission to use the lock, as the river below is infested with boaties and houseboats. It is puntable (albeit quite deep) and a bit of an adventure. The Wren Bridge There's an engraving of third court, with the bridge in it, on one of the piers facing the bridge of sighs.
It was written over thirty years ago, but this will still be terribly familiar to anyone who's been to a conference with a science angle to it... Quoted from Nature 272 , 743 (1978). "I thought that in the eight minutes I've got I'd bring you up to date on what our group has been doing in the last year; in a sense this is a progress report and updates on the paper we gave here last year; I won't go over the nomenclature again; could I have the first slide please - oh, I think you must have someone else's box - mine is the grey one with my name on the top, no, wait a minute, not my name, whose name was it now? Ah yes, you've found it; there's a red spot on the top right hand of each slide - that is the side that becomes the bottom left when you project it. OK, you've got it now, let's have a look, no, that's the last slide not the first, yes, now you've got the right one but it's on its side, what about the red dot? There are two?
To be honest the Geocities website got updated intermittently at best - and wasn't much more than an assortment of odds and ends. The photos had long since moved to Facebook (Geocities' bandwidth wasn't up to the job, click 'refresh' a couple of times and it was all over for the next hour), an the most popular sections seemed to be - for reasons that were never entirely clear, but something to do with Google - a large page of chemical hazard symbols (see here - and still live for now) and 'photos of swiss people'. This page, for what it's worth, is the replacement. For something more recent, here's a short interview I did for the St John's College alumni blog.