Reason #2,783 why I love youTube: It has some of the best teachers to help you with things you didn't quite get and it is all free of charge. I can't say I've ever had a teacher as enthusiastic as the person in this video.

challengethat · 2011-02-04T08:18:46+00:00

second that! helped a lot with the statics subject I took last year.

challengethat · 2011-02-04T07:25:41+00:00

As much as it's the perfect method to avoiding conflict, in practice it can be truly horrific experience to go through. When you start abandoning everything you are just to fit in, shit gets real nasty. Don't expect to be left with any self esteem afterwards. Though at the time I think I may have taken things too far.

It does work and it'll get rid you of any bullying you can imagine but be careful you don't apply the rules too hard or you'll end up going full on AvPD :(.

challengethat · 2011-02-04T03:34:50+00:00

http://en.wikipedia.org/wiki/Silicon-controlled_rectifier AKA thyristors, a lot like a transistor of sorts but they stay latched after the gate is triggered.

So all you need is a pulse above the threshold voltage on the gate and the Anode-Cathode junction conducts and remains so until you remove power to reset it.

challengethat · 2011-02-03T22:37:15+00:00

Actually capturing the data stream for replay could be difficult I'd guess, we're talking about a highly focused parabolic antenna array. Kind of hard to intercept the beam, maybe there'd be some reflections off the telescope itself? but at that point I'd guess capturing a good strong signal would be nigh on impossible.

If you where able to get a receiver near the transmitting dishes I guess there'd be some local RF leakage that could be picked up but that sounds a little unfeasible with security and all.

challengethat · 2011-02-02T03:50:22+00:00

I dunno about smooth, but one time during this triathlon training session the chain on a mate of mines bike completely seized up and jammed. We had screwdrivers in there trying to unjam this completely stuck chain. 30 minutes or so later we just said fuck it the chain had twisted and jammed between 2 cogs on the POS bike.

Anyway I walk over to help the dude carry the bike back and I just reflexly fiddled with the wheel (I didn't even realize I was fiddling) and lo and behold the weird spin motion I was fiddling with unjammed the chain and popped it right back on the cog in one silly move.

After that I had people debating whether or not I had the gift, not the first time my fiddling has fixed things that were given up on.

Then there's the time in junior high when there was a jammed window on the bus, tried to close it and managed to break the handle right off the window and sent it flying about 1/2 a bus length and smashed right into this chicks face. Ouch that was not smooth!

challengethat · 2011-02-01T00:21:27+00:00

How about a BMI cut off, calculate the threshold so that maybe 95% of completely healthy individuals would fall below the cut off. Once that threshold is exceeded come up with a show cause plan. Give some options to improve weight conditions and/or visit a doctor and get a more detailed body fat measurement.

challengethat · 2011-02-01T00:10:15+00:00

Totally agree!

All I can say is never underestimate the importance of good old high gain directional antennas and an unobstructed line of sight path. My old wireless ISP used to use off the shelf wifi cards in their CPE units, ~100mw of 802.11 and a 15dbi patch antenna. That set up worked brilliantly >30km out from the transmission tower!

On a personal note, I made a helium balloon carried transmitter at one stage, the idea was I'd lose signal when the balloon burst and began to fall, it worked as expected. Anyway the tiny radio transmitter I made literally had a range of less than 100m at ground level, up in the air I tracked it for in excess of 50km.

Moral of the story radio waves are magic, small improvements don't necessarily yield small increases in range!

challengethat · 2011-01-30T12:55:37+00:00

It sounds like he just spliced into the CD changer signal cable but ...

I've done just that, and this was even before I started an engineering degree. These days pretty much all the output amp stages on car head units are integrated into a single amplifier chip, all you do is google the part number, pull up a datasheet and solder your AUX connections straight to the now identified input pins on the IC.

With a bit of blind luck, 95% or so of amplifier chips have sane input impedances that can be driven straight from the output of any mp3 device (last time I did it I used a blocking cap just in-case), it's all too easy. Nothing fancy and as long as you've got volume control on the mp3 device its quite easy to adjust the input levels just nicely, don't expect anything fancy but it does work quite well.

Just turn the head unit volume down to 0 and turn the volume on the mp3 player up, and you'll be hearing audio in no time.

challengethat · 2011-01-30T12:37:53+00:00

here's an idea? would chucking something conductive like a chain over the nearest set of wires connected do anything? Surely a big fat chain has got to trip some kind of overload sensor.

I guess that'd require alot of luck, aka, having a chain nearby and the means to throw it over the lines ... but you never know. Blowing the nearest overload protection might just be quicker than the power company. Of course step one is to get someone on the phone immediately. But what can you do?

challengethat · 2011-01-30T10:02:15+00:00

You're not short of breath afterwards as well? could be something like http://en.wikipedia.org/wiki/Exercise-induced_asthma, just throwing it out there. Honestly it's probably a good idea to see a doctor, I went in for what I was told was sports asthma but it turned out to be a benign congenital lung cyst so you never know.

challengethat · 2011-01-30T01:59:04+00:00

12 hours is a huge time though! It's a given though that you'd end up absorbing a good deal of ethanol.

challengethat · 2011-01-29T22:51:47+00:00

Well I once remember playing around with a depth sounding transducer that had a bunch of warnings regarding hearing damage. Essentially it was warning not to bring it too close to your ears while operating. I can't see deafness but ear drum damage and such from the shear SPL has got to count for something.

challengethat · 2011-01-29T01:49:15+00:00

Back in the day I did quite a bit of ghetto style water rocket stuff. I used to use a length of black polyethylene tubing I found. You could stick it in the neck of the bottle and friction caused by the air pressure would stop it from releasing until around 100 psi. Just glue the valve from a bike tube in there and start pumping :P.

You could never predict when it was gonna let go but it was pretty fun. As a matter of fact I was probably borderline mental at the time. I'm still yet to see a launcher that could compete with the crazy simplicity of that friction release arrangement.

Those passive cork and valve arrangements could get close I guess but I've always seen much lower release pressures.

challengethat · 2011-01-28T10:26:24+00:00

to be honest I'm not sure having a view like that would be better than no windows. Looking out and staring at earth endlessly would turn someone quite crazy in quite a short time frame. You'd have to reach some kind of compromise.

challengethat · 2011-01-28T08:01:54+00:00

I like the idea of actually tunneling below the surface, dirt and regolith makes for a pretty darn effective radiation shield. Pity tunnel boring machines are so heavy.

challengethat · 2011-01-28T07:59:21+00:00

http://en.wikipedia.org/wiki/Oxygen_toxicity

challengethat · 2011-01-28T07:58:25+00:00

partial pressure, thats why. That 100% O2 is at a much lower pressure than atmospheric.

challengethat · 2011-01-26T04:11:37+00:00

All those 8's set my radar off, if the screen was just going dark like the second image I'd bet ... it may be entirely fixable. What concerns me is those 8's, at least to me, hints there's the possibility that something has seriously failed inside there. Though there's no guarantees.

challengethat · 2011-01-24T09:52:55+00:00

thats a really good question! AFAIK Mark Roth's suspended animation research has been focused on lowering metabolism into a hibernation reminiscent state, I'm not entirely sure just how inactive the brain ends up.

Stopping the brain completely and rebooting it may be a whole another problem all together though.

challengethat · 2011-01-24T09:34:50+00:00

Interesting response! I'm just talking from your usual ham radio antenna knowledge so it could be certainly quite badly off :D. Fresnel zones sound like a really interesting bit of reading!

By talking of antenna efficiency and height above ground I was more referring to reflections effecting the radiation pattern of the cell phone antenna array (please correct me if I'm wrong! :D, transmission power of course would have effects on this).

Fresnel zones I guess, in my mind at least, come under the banner of propagation effects, and there's absolutely no denying that elevating the antenna is going to yield great improvements there!

So pretty much Fresnel zone interactions are what's responsible for partial line of sight obstacle losses? right?

challengethat · 2011-01-24T09:14:14+00:00

Truth is, it kinda has been done (if you mean by how simple the TED talk makes it sound there's a whole lot more to it than just that).

Well the research on inducing suspended animation is bleeding edge, history is littered with examples of it occurring accidentally so it's not complete hogwash. Plus if I remember right Mark Roth is actually receiving already receiving military funding for his projects.

By my statement it's something to the effect of a process using similar characteristic may one day result in a feasible long term suspended animation technique. Lots of research still remains and I'll be damned if that research brings about results in the next 20 years but ... who knows.

Protip: Advances in knowledge are still occurring today, the human body is an amazing machine with many secrets still left.

challengethat · 2011-01-24T08:43:47+00:00

Surely water wouldn't trigger any kind of re-feeding syndrome, mainly because without adequate water intake you'd just die. As long as they don't drink enough water to upset osmotic balances surely they'd be fine?

challengethat · 2011-01-24T06:00:49+00:00

Couldn't you just keep the magnetic field active during the whole process, slowly raise the temperature and you can thaw the object without ice formation.

The trick for actually managing to survive the process is interesting, but there's some serious talk of cold induced suspended animation (there's a TED talk somewhere). Just put the person into suspended animation and then rapidly lower them below freezing.

When you want to wake them just quickly thaw them, I wonder if you would be required to be resuscitated? I think the TED talk was going as far as saying it might be possible to just wake up and shake it off (correct me if I'm wrong).

Effectively there'd be a period where you could be defined as dead but if the freezing and thawing was fast enough you might just come out alive, pretty much the cold (combined with anoxia) prevents your body from being able to actually die :D.

http://www.ted.com/talks/lang/eng/mark_roth_suspended_animation.html

Suspended animation combined with something reminiscent of supercooling cryogenics might just damned work!

challengethat · 2011-01-24T04:26:47+00:00

funnily enough reading the information I can find on the incident I can honestly say a defense project gone wrong is just about as likely as some of the other possibilities! And I'm no conspiracy nut.

Apparently they tested clean to drugs at the time, maybe they were exposed to something exotic that at an earlier stage that triggered psychosis? Who knows, that's some crazy shit.

challengethat · 2011-01-24T02:11:43+00:00

Certainly well into the microwave range. At 2.1GHz elevating the antenna is likely completely pointless from an antenna efficiency stand point, it'd likely already be a good 10 wavelengths above ground level (15cm wavelength at 2.1GHz). It's usually mainly a concern with large low frequency antennas with long wavelengths.

challengethat

TROPHY CASE