Tuesday, April 27, 2004
Monday, April 26, 2004
Here's a random idea. Remember the Kyoto Protocol was an international agreement to cut CO2 emissions in an effort to curb global warning? Granted that it's dead now, thanks to the Bush administration (I've never understood what the problem was there), but it was a good idea while it lasted. Back to the point: I had a completely off-the-wall idea as to how net CO2 emissions could be reduced by a country, even if not eliminated.
Recent proposals for a Mars mission have recommended that an away team do not take oxidiser or propellant for the way back, but rather generate them in situ. The preferred way of doing this seems to be to take hydrogen to Mars (it has a low molar mass, so you can take a large amount of it for a relatively small mass), and then use the hydrogen to "crack" the CO2 in the Martian atmosphere to make methane and oxygen, which would be used to fuel the homebound trip. Note that this process:
- generates 1 mole of methane for every 4 moles of hydrogen
- generates 11 kg of reaction mass for each kilogram of hydrogen
- requires some technology to store the generated gases
- is pretty power-hungry.
- electrolyses water to generate hydrogen and oxygen
- stores the oxygen, and uses the hydrogen to "crack" carbon dioxide
- stores the generated methane and oxygen
Advantages over growing forests: methane can be burnt a lot more cleanly than wood can (lower soot output), and the system can be used in areas where vegetation can't be grown easily. Disadvantages: forests look nicer, they can be used to generate secondary income (through visitors etc), they're good for the local ecology, they have lower maintainance requirements and building them doesn't generate pollution. Basically, if I had the choice I'd plant trees rather than use the scrubber.
The sad thing is that I can envision getting governments to adopt the scrubber a lot more easily than getting them to plant extensive forests.
Sunday, April 25, 2004
- Moonwar (The Moonbase Saga) - Ben Bova
- The Moon Is a Harsh Mistress - Robert A. Heinlein
- Gatecrasher - Experience - Various Artists
Friday, April 23, 2004
Now my Easter break is over , I'm going to pick up with a more detailed analysis of the Solar radiation environment .
The Sun's outer three layers are responsible for the majority its electromagnetic radiation. The photosphere, at about 5900 K, emits visible wavelengths; the chromosphere above emits more intense ultra-violet radiation; and the corona, the Sun's outer layer, gives out X-rays. The chromosphere has temperatures up to 10,000 K, and the corona reaches temperatures greater than 2x106 K.
The radiation pressure of the Sun's electromagnetic emissions is sufficient to drive of huge amounts of matter in the form of the solar wind. At one AU, the solar wind has a flux of about 9 protons cm-3, travelling at an approximate mean velocity of 450 kms-1.
Disturbances in the Sun's atmosphere are the cause of solar flares, large plumes of material thrust out from the Sun's surface. Associated with flares are increases both in radiation and high energy particle fluxes. Near the Earth the first observable change is a sudden and relatively brief increase in solar radiation about 20 minutes after the flare occurs, and then about a day later a longer burst of high energy particles, similar to the solar wind but more intense and at higher velocities, typically 103 kms-1.
As discussed previously, the enhanced electromagnetic and particle emissions pose a substantial risk to exposed equipment and personnel.
J. P. W. Stark (2003) The Spacecraft Environment and its Effect on Design. In Spacecraft Systems Engineering (J. P. W. Stark, G. G. Swinerd & P. W. Fortescue, ed.), pp. 11-47. John Wiley & Sons Ltd, Chichester.
Thursday, April 22, 2004
Looking back, it's a very long time since I last updated this weblog! So much has happened since then.
Wednesday 31st March to Saturday 3rd April was the run for Bye Bye Birdie. That was an amazing show, though I say it from a participant's point of view. The music was rythmical, catchy and in tune; the choreography was unbelievably precise, and the actors truly lived their roles. I have never been involved with a more professional youth production. I was really sad when it was all over - but then again, the cast party after the last performance was tremendous fun! Mr & Mrs H. came to see it, and they both said that they really enjoyed it.
We got home from the party at about quarter to two in the morning on Sunday 4th April, a mere 6 hours before we had to leave home to go to our OCYO course at Sibford School near Banbury. Needless to say, I found playing the horn rather taxing that morning. But despite the fact that the OCYO course was on a shoestring budget and very hard work, I had a great time. For the first time when I've been on OCYO, I felt that I was with a group of real friends, T., E., L., & J., who I spent nearly all of my time with while I was there.
An amusing thing happened during the OCYO course. As I've previously mentioned, we're playing Shostakovich's 5th Symphony, and I'm playing first horn. Now, the first entry in the symphony for the first horn (after 36 bars rest) is a top G followed by a descending passage. All through the first couple of days of the residential course, I didn't get it right once - my lips just let me down, probably still tired from the exertions required by the show. On the last night of the residential course, we had the OCYO cabaret, and one of the features was the presentation of humourous awards to members of the orchestra. I won the much-coveted title of "Most Enthusiastic Player", and upon mounting the stage in a very keen manner was urged to play something. I immediately launched into that very entry - and got it perfectly right. I think I was even more suprised than our conductor!
Regrettably, having had two weeks of great fun, I was due some bad luck, and on Maundy Thursday Lizzie and I split up. It had been clear to me that our relationship was foundering - and, apparently, she'd been thinking of splitting with me since New Year - but unfortunately she still hasn't actually explained to me exactly what I was doing wrong. I really wish she had.
Anyway, so that's all the notable stuff that happened over the Easter break, apart from pre-season shooting immediately before we returned to school yesterday evening. We went to Pirbright and shot for three days. And that's about it, really. Apart from my suprise at the impeccable behaviour of the juniors - we didn't have any trouble from them at all!
Ah yes, I nearly forgot. On Friday 2nd of April I had a Year in Industry interview at Sharp Laboratories of Europe, following which they offered me a job which I've accepted. So next year I'm going to be designing LCD screens! Not quite what I was expecting to be doing, but it sounds like it's going to be great fun all the same.
So, having managed not to do any significant amounts of revision or horn practice for far too long, I must now stop typing random gibberish and do some of both. Or either.
UPDATE: Other stuff that happened of note included cycling to Cheltenham and halfway back; finally visiting Lisa (in Cheltenham); meeting Zoe on the aforementioned trip; and playing Achaea a lot. And if your interested, the team I'm going to be working with next year have a website here.