Roland’s homepage
My random knot in the Web
Roland’s homepageMy random knot in the Web |
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This used to be a very unchanging page. I’ve decided to change that, and put updates on top. Think weblog-style, but without the overhead. :-)
Over at the walden effect blog, they were looking for cheap creek crossing options that didn’t require much infrastructure. My solution is a tensegrity arch bridge (or tied-arch bridge) that doesn’t require elaborate abutments.
The glulam beams are loaded lostly in compression, because of their shape. According to NEN 6760 (see “Sterktegegevens van hout”, in Dutch), woods in the lower strength classes C14 to C18 are twice as strong in compression as in tension, and are stronger in compression than in bending. The wires on the underside prevent the need for abutments becaue they can carry tensile forces. Since they also prevent the ends of the arch from spreading, they also help eliminate bending in the arches.
A poll on the Ecovelo website made me ponder the distances I covered by bike and by car last year. I realized that the distance I covered by bicycle last year was at least double the distance I covered by car. I’m genuinely pleased with that!
The only snag I had this winter that the bowden cables operating my hub gear froze when it was below -5°C. :-( I might have to take them apart and dry them.
(Even with the recent snow, the cyclepaths in and around Eindhoven are being kept nicely snow-free. Three cheers for the people keeping them clear! It’s very much appreciated!)
As an avid user of TeX, I was pleased when my new TeXLive DVD arrived. The update process has been documented on my UNIX miscellanea page.
The binaries that I have compiled for FreeBSD 8.0 for the amd64 architecture are available as texlive2009-freebsd8-amd64.tar.bz2.
Some security notifications and an errata were release on 2010-01-06. Since I tend to use the affected components, I’ve updated my system as documented on my UNIX miscellanea page.
I’ve been reading the waldeneffect blog, and a comment thread there led me down some interesting avenues that I’d like to share.
When they blogged that a power outage stopped the fan in their furnace from working, I immediately thought that it would be neat if there were fans driven by the heat of the furnace, e.g. by a stirling engine. Some googling later, and we have a stirling-driven fan.
By the by, the thread turned to solar power, and I did some calculations based on numbers I could find. Basis for the discussion was a Northern Industrial solar panel, with a rated power of 15W, costing about US$100.
On the fast facts page of the solarbuzz website, I found the following info. A solar system of 1 kW peak power will annually deliver;
(As an aside, 1 kWh is = 3.6 MJ)
So a small appartment (definitely cloudy climate, say 2100 kWh annually) would need an installation with 3 kW peak power to be self-sufficient in electricity. Extrapolated from the same website such a system would cost around €19000. The total cost for an installation with the cheap solar panels I estimate at €23000. Assuming an electricity cost of €0.25/kWh, this installation would save €525 in electricity bills per year. Clearly this is not a cost-effective investment at this time.
Studies have shown a negative effect of patents on software development. So I’ve signed the petition. If you, dear reader, are a citizen of a country in the European Union, please sign as well!
The free software Theora video codec, can together with the Vorbis audio codec and the Ogg container format produce very small files with good quality. Read all about it on my UNIX miscellanea page.
To all my family and friends everywhere!
This is the start of my new homepage format. I decided that my homepage was overdue for a makeover, which will be done in phases due to the amount of work involded.
Copyright © 2010, Roland Smith rsmith@xs4all.nl
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