Archive for category Technology
COLLISIONS!
Posted by Tom in Physics, Science, Technology on November 24th, 2009
So as you may well be aware, the LHC started up again this weekend after a good 14 months off.
September 10th last year was the date penned for the long overdue startup of the Large Hadron Collider – the worlds biggest (and best) particle accelerator. Unfortunately a problem with the cooling system caused a leak of liquid helium and a saftey mechanism called a quench kicked it. It basically ruined a few magnets so the whole thing had to be shut down to be fixed.
Well, it was fixed, and this weekend saw the grand reopening. On Friday evening, the various LHC control rooms were full of physicists and excitement as the beams were reinjected into the machine. First one way around, then the other. The plan, as us postgrads understood it, was that collisions (ie, two beams in the LHC going in opposite directions and brought to a focus at the detectors) were not due until early December.
Well, we were wrong. Today (the 23rd November), the LHC injected beam 1 into the LHC, then injected beam 2 and started ‘beam synchronization’. I don’t fully understand what that means, but I know that there was one bunch per beam (about a metre in length worth of protons), and my best guess at ‘beam synchronization’ is that the two bunches were brought close together.
Obviously the beams weren’t focussed and we weren’t running at anything close to design luminosity, but a few collisions occured in all 4 detectors. An exciting moment for everyone involved with the LHC, indeed.
The CERN Press Release of the weekend’s events and a summary of the collisions explains a bit further what the goings on were this weekend, and what the plans for the LHCs immediate future are.
The coming months should be an exciting time for particle physics, and the coming years will hopefully shed some light on the darker corners of the Standard Model and beyond…
A Space Odyssey
Posted by Tom in Astronomy, Science, Technology on July 28th, 2009
It’s been 40 years since the Apollo missions and the first manned lunar landings and I, for one, have been watching the TV programmes quite a bit. It’s all the same old knowledge though, filled with things everyone already knew. The crew of Apollo 11 underestimating their position and having to land in precarious circumstances, the cancellations of the later Apollo missions due to lack of political will, the more recent US revival in space exploration by ‘Dubya’ and his directing NASA to get a man on Mars in the next few decades.
What I found more interesting was the missions planned by other nations. Particularly China.
OK, so many people know that China have a lunar exploration programme. Many people know that China plan to land men on the moon around 2020/30.
What I didn’t know was that following their manned missions, China will begin construction of a permanently occupied lunar base!
If this did happen, it would completely change space exploration. I’m thinking along the lines of 2001 here. Minus the evil computer.
Whoever decided to build an extremely powerful artificial intelligence and give it a BRIGHT RED EYE anyway?!
A lunar base would not only be exceedingly cool, but would offer a ‘recharge station’ for spacecraft going from Earth to more distant destinations, not needing anything like the huge rockets required to take a craft to the escape velocity of Earth. Taking off from the Moon would be a much easier task.
Hopefully once it’s all completed the Chinese will share their lunar base with the other nations, perhaps there’ll even be an Earth-wide space exploration programme and all of the political agendas involved in space exploration will be gone. Maybe I’m wishing there though.
None of this is fully OFFICIAL yet, but the renewed interest in space exploration is definately a good sign of things to come!
Further reading:
R.I.P Stirling Engine
Posted by Tom in Science, Technology on July 27th, 2009
Ok, it’s official. I am rubbish at building Stirling Engines…
It doesn’t work, despite extensive testing and the use of THREE candles to heat it.
The Stirling Engine project is dead. This saddens me.
At least it gave me something to do for a few weeks.
Stirling Engine Part 2
Posted by Tom in Science, Technology on July 25th, 2009
Stirling Engine number 2 is completed and it seems like it may work. Everything is as airtight as can be, the balloon pops in and out when the piston moves so hopefully it all should work.
Initial testing was less than encouraging though. The crankshaft seems to meet a bit of resistance in its cycle and prefers not to comply with gravity and let the piston fall from the uppermost position. Creases that need some ironing out.
Possible explanations for the poor performance in initial testing:
1. The heat isn’t great enough. I was only using one small tealight candle and, while it did manage to reach a too-hot-to-touch temperature, it may still not be hot enough. I will try again tomorrow with more candles.
2. The crankshaft doesn’t rotate as smoothly as it should. Perhaps oil would help, maybe an attempt at straightening the crankshaft as much as possible.
3. There is an air leak. Although the positive response when manually moving the piston seems to rule this one out.
4. I am just useless at making Stirling Engines. This one is always in the back of my mind, and if all else fails, this is the most likely explanation. Maybe I’m not cut out to work with hardware and should stick with the software side of things…
The Stirling Engine
Posted by Tom in Science, Technology on July 19th, 2009
It’s a simple enough premise. Take a pressure chamber; a piston that fits snugly, but not too snugly, in it; a diaphragm to force the piston back down and add heat and what should result is a Stirling Engine. It’s not quite as simple as that, it turns out. There are a few designs, but the simplest one is the single cylinder design, as seen here.
This week I started on building one.
My first attempt involved using a standard Guinness can for the pressure chamber, with the top cut off. The top of this chamber is then another Guinness can with the top cut off, then glued to it, so there’s a kind of bowl on top. This chamber houses the displacer piston, which I crafted from a large Red Bull can, again with the top cut off, to make it around an inch and a half high, with the bottom of a Dr. Pepper can glued to it.
From then, it’s a case of drilling a hole in the side of the chamber, gluing a PVC elbow to it, wrapping a balloon over the pipe and adding a crankshaft, with rods to push/pull the balloon (the power diaphragm), and to be pushed/pulled by the displacer piston.
Simple enough?
Well, not quite. It turns out the Red Bull can is too narrow for the chamber, which lets all the air free too easily. Add to that a slightly rushed design and you’ve a recipe for disaster. Or at least a non functional Stirling engine.
Well, at least it LOOKS cool.
Since then, I started on a new design, which I am being a LOT more patient with. I am also replacing the Red Bull displacer with another standard sized can with the top and bottom cut off, cut into a strip, then glued back together to give it a slightly smaller diameter. So far it fit’s pretty snugly in the chamber. Here’s hoping it’ll work this time!
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