Dan's Data letters #161Publication date: 7 March 2006.
Last modified 03-Dec-2011.
Ideally, it should involve a conveyor belt
Having moved house and changed to an ISP with a very liberal view of download limits (i.e. there aren't any), I find myself deluged in video files, which I don't have the inclination to burn to DVD and watch on the telly.
A lot of this data doesn't change or get used much (the Doug Anthony All Stars aren't exactly bringing any new material out anytime soon...), so a nice easy method of storage is to burn a heap of junk into a DVD spindle, like a plastic data fortress. The issue is manageability.
A Storage Silo Of Doom sounds like a really cool idea, but what I think I need to keep it coherent is some decent cataloguing software. A little database of what's on where; more importantly, letting me browse and re-organise content in said database without needing to be fed with discs. The usual suspects didn't turn up anything useful; again, wondering if you know of any?
Regarding the hard drive: <Klaxon noise!> Any time a consumer drive shows any sign whatsoever of illness, it's time to replace it. This is how you show your gratitude for the drive's kindness in giving you some warning.
Regarding data management: It's hardly high tech, but for stuff that you actually want to have easily to hand (as opposed to stuff that you're only keeping in case someone else wants a copy of it some day), I like those hang-on-the-wall "CD wallpaper" products. I've got a couple of the 24-pocket ones on the back of my office door, full of original game CDs and recent backups and such; you can also get a larger version for doors only that hooks onto the top and bottom of the door, so you don't have to hammer in any tacks.
You get 110Gb per 24-disc sheet if you're using 4700Mb discs, which isn't bad. CD wallpapers show up cheap on eBay all the time, and you can tape them onto the walls if you don't want to make holes.
As far as cataloguing goes - I haven't used it, but CatFish is widely recommended.
And a chute leading to an incinerator
I'm looking for a gadget that detects the approach of a distributor of junk mail, and announces (politely or otherwise) that I wish only genuine Postal Service items put in my letterbox.
It seems to me that some combination of close-range motion sensor, as used in security lights, and the digital recording bits of an answerphone ought to be possible. There doesn't seem to be such a thing on the market, and I'm a total soldering-iron-phobe, but perhaps some simple hook-up could be done.
People get totally hysterical about spam, but really it's the junk mail that annoys me. It clogs up the letterbox, bits stick out and induct rain into the box soaking the few letters you actually want to receive, and if you go away for a few days the box starts waving up and down the street "Burgle Me!" I lost a small packet that should have been delivered over Christmas, doubtless because the mailbox was full to overflowing, so the package was left outside where it was vulnerable to casual theft.
Stickers don't seem to do the job, but maybe a disembodied voice would have some effect. The dinkum postie would get used to it, pretty quickly.
Something close to what you're looking for exists as a commercial product now. I couldn't find anybody in Australia or New Zealand who sells them, though, and you probably don't really want one.
In order to be sensitive enough to make its announcement before the low-paid person-with-a-little-red-wagon-full-of-crap has already dropped a pamphlet into your mailbox, such a gadget would also have to be sensitive enough to trigger when people were just walking past. That would, if nothing else, make passers-by think you're a loony.
IR sensors also have problems in sunlight (the sun's a massive IR source...). You could adapt a door-beam arrangement with a sensor at the end of a shade-pipe, or try an ultrasonic sensor, but the more I think about this, the less enthused I am.
I'm thinking it'd be more practicable, and less obnoxious, if you used a mailbox whose lid has to be opened to put mail into it, and rigged a conventional voice recorder to a microswitch that triggers when someone lifts the lid. Easier to weather-proof, you could use a cheap tamper or car interior light switch as the actuator, and no midnight dog-walkers would be warned to Step Away From The Mailbox.
Mind you, I've found that the old "no unaddressed mail" sticker works pretty well. When we had one, we still kept getting stuff like real estate agent fliers offering to help us sell our rented house, but that doesn't take up much room; the glossy junk stopped.
(Since then, we've decided that we actually quite like paper junk mail. I'm a particular fan of the incredibly masculine Gasweld fliers.)
Another young poisoner
Did I harm my parents/me?
You see, when I rather young I found a medical thermometer in the cupboard, the type which contains mercury - and has a small scale, as it was intended for measuring whether you had a fever or not.
Being the idiot I was at that time, I thought it would be a good idea to play with it.
When we boiled a kettle in our house the water we did not use was placed in a thermos flask, so that it could be used again at a later date, or reheated if it needed to be boiling.
Anyway, I stuck the thermometer into the rather hot water inside the thermos flask. Because the thermometer was not designed for these temperatures, the bottom broke of when the mercury expanded. The contents of the thermometer went straight into the water.
Now, if I had been a bit more intelligent at the time, I would have flushed away all the water and cleaned the flask etc etc. But because I was scared stiff of getting into trouble I had to cover up the evidence.
I decanted as much water as I could from the thermos flask into a container, without letting the mercury escape. I then (for some odd reason) poured the rest of the water from the thermos, containing the mercury and glass onto the sink draining board. I can't remember why I just didn't just chuck the contents straight down the drain (would have been more logical). I think it was because I wanted to examine this rather interesting metal.
Anyway I played with it for a bit. I remember being amazed on how easily it rolled. After that I washed down the sink and the mercury went down the drain.
As for the remaining hot water that I decanted into the container, that was returned into the thermos. I was hoping no one would notice. Also, the remains of the thermometer were placed back into the cupboard.
Anyway, my question is, do you think I harmed my parents/me? (Considering that they drank that water from the thermos.)
The scientific part of me thinks that the concentration remaining in the thermos would be so low that it would do little harm... and also as the water was hot, any remaining mercury traces would evaporate quickly.
But I still feel guilty and this was all brought back when I read your letter replies.
What do you think?
What broke the thermometer probably wasn't the expansion of the mercury - it was probably thermal shock. Cool glass, hot water, "tink!".
Ordinary non-"Pyrex" glass can still resist mild thermal shocks quite well, and usually the 70-degrees-C-at-most change from room temperature to near-boiling water won't be a problem. But, over time, household glass (which is moved around, and touched against things, and stored in air) develops more and more microscopic surface cracks. Even if a glass object just sits on a shelf, air molecules bouncing off its surface will create super-tiny cracks. The result is that the older glass gets, the more prone it becomes to sudden breakage (well, unless you periodically melt it down and reform it).
This is why an old glass can survive being knocked against other glasses, dropped into the sink, and similar rough treatment, then suddenly break one day after quite a gentle knock.
If a self-propagating crack - one that releases stress as it propagates - starts in glass, it propagates very quickly, so you can't see where it started and it looks as if the object just instantly came apart. In some cases this can look quite bizarre - you pour hot food into Grandma's glass bowl, you carry it to the table, you put it down, and 30 seconds later the heat stress causes a crack to cross the propagation threshold and BAM, the thing's in two pieces. If this happens while someone's saying Grace, strange opinions about the will of God may result.
The problem with your young self's brilliant down-the-drain idea, apart from laws about disposal of hazardous materials, is that your drainpipe isn't a straight drop into the sewer. It's got an S-bend in it. And a good thing, too; without that S-shaped water trap, foul sewer gases could flow up through the plughole.
Toilets have a similar setup, except you can see the level of the water in the S-shaped portion - that's it in the bottom of the bowl. The water in a sink S-bend isn't readily visible, so it's easy to forget about it.
The S-bend lets water and reasonably lightweight material through with no trouble at all, but dense things will just sit in the bottom of the bend and never be flushed through. This is good news for people who lose their wedding rings in the sink, and it also means that mercury poured down the sink will stick around.
Mercury is about 13.5 times as dense as water (lead is only about 11.3), so it definitely won't be washed around the S-bend by anything short of a full-blast garden hose stuck down the plughole.
It will, however, slowly leach away, one way or another. Chlorine in the water passing by could, for instance, react with the mercury to make mercury(II) chloride, which is (a) water soluble and (b) fairly horribly toxic. It'd be made so slowly in this situation that your waste water would probably be insignificantly polluted with the stuff, but over the years this mechanism would be enough to get rid of the whole blob.
If the drain blocked up and someone threw some sodium hydroxide drain cleaner down it to clear it out, I think that'd react with the mercury to make an insoluble (and, once again, quite nasty) precipitate that'd be washed down the drain. This would work especially well if the NaOH solution was prepared the way I always used to do it:
(1) Fill large vessel (an all-plastic pump sprayer, if you're brave) with cold water and ice cubes.
(2) Don eye, hand, arm, leg, foot, torso and crotch protection.
(3) Pour in sodium hydroxide, stirring vigorously.
(4) When the water starts boiling, you're ready to clear some drains, de-grease a grease trap, or turn a heretic into soap.
Um. Where was I?
Oh, yes. The water in the vacuum flask wouldn't have been significantly contaminated with mercury. Metallic mercury isn't water soluble, and there wouldn't even have been any chlorine to speak of in the water, since it'd been boiled.
(Just leaving chlorine-y tapwater to stand for a while will let the chlorine bubble out of it. That's all that's necessary to make many public water supplies taste as nice as expensive bottled still water.)
Not a regular reader, I take it
I like your site and I get good information from it. I am an iridologist and I have 3D software to scan the iris from a jpeg image. However the computer only recognises grey scale so the scan is relatively useless. I want to scan the iris with a low powered laser or other type scan... any comments?
I did have a comment for Sam. That comment was:
Sam was, for some reason, less than pleased with this, and invited me to "comment on things you know about". So I went on to say the following:
I do know about iridology - well, I know about as much about it as I know about cargo cults, yogic flying, and a variety of other things which share with iridology the fact that evidence for their truth becomes less and less impressive as the tests to see whether said evidence is fake become more and more stringent.
I know of no proper scientific tests that have ever supported the idea that iridology works. It's quite simple to design such tests - multiple practitioners, unable to communicate with each other, performing diagnoses on patients with known illnesses, for instance - but iridology invariably fails them. Practitioners can't even agree on their diagnoses, much less discover what's actually wrong with people without reading out a laundry list of every vaguely plausible illness.
If you can show that iridology works in a properly controlled test, you can revolutionise health care; vast amounts of time-consuming and expensive diagnostic tests and machinery could be replaced entirely by your marvellous specialty.
Oh, and you could win a million dollars from James Randi, too.
Off you go, then!
Occasionally you come across something in the memepool (.com) that stands well above the dross.
I'm kinda glad he grafts these things together Sid-From-Toy-Story-style from previously existent toys. He does it very nicely, don't get me wrong, but it's much less disturbing this way than if he was one of the "first, I assemble my own materials in a cyclotron..." types.
In the same vein, I regret to say that the Orange Blossom Special is not actually steam powered. Like the other members of the elite club of Monster Tanks, it's got a damn great internal combustion engine (or two) hiding in there.
Regarding the obvious future of steam power - Iain M Banks wrote a book that featured a planet rich in fissionables, whose occupants' best idea of what to do with them was to make nuclear steam locomotives. Hey, when you've got rocks that are hot all the time, and get hotter when you put lots of them together, why not?
Needless to say, atomic locomotives were one of the things that were considered around the same time as nuclear powered bombers. Locos were a more feasible idea, since they could be built much more heavily, and thus were less likely to leave a radioactive plume behind them by design, and could be better shielded, and could also be simpler - an atomic loco is just a steam loco with a different kind of fire under the boiler.
Call Guinness, then drink Guinness...
"His blood-alcohol level was so high that it had the effects that experts say is near surgical anaesthesia."
That's pretty impressive. How near was he really, though?
A true blood alcohol content of 0.40% (as opposed to the somewhat variable results given by breath analysis) is the accepted LD50 for alcohol in normal people. That's a 50% chance of death.
Dedicating yourself to serious alcoholism, though, can increase your tolerance by a factor of two or more. If you're a rummy with a 2.5X tolerance increase, a .345 BAC would be equivalent to .14 in a normal person, which is definitely in the passing-out range.
Just drinking until you pass out, however, does not necessarily render you insensible to pain. You might not notice all of those penises being drawn on your face by your mature and cultured friends, but you probably would still wake up upon the application of painful stimuli substantially short of someone cutting you open and looking for your gall bladder.
The lofty height of a 1% BAC, however, might well do the trick. Unfortunately the question is somewhat moot, as 1% has to my knowledge not yet been verifiably achieved by anybody who's survived. Keith Richards and Shane MacGowan have both, regrettably, been too busy to assist researchers with these inquiries.
For the benefit of those readers who wish to try their luck, the rapid consumption of an entire 700ml bottle of 40%-ethanol spirits will, in the unlikely event that you manage to absorb all of the alcohol, increase the BAC of a normal-sized male human to something like 0.93.
A couple of litres of water along with your bottle of Stoli would reduce the concentration enough that the stomach might think about letting it through, but you would of course still probably just puke. A large dose of The Suicide Enthusiast's Friend, motion sickness pills, might help you keep it down.
Or, heck, try intravenous ethanol! It's good for what ails you*!
* "What ails you" herein defined as "alcohol withdrawal" or "ingestion of a lot of antifreeze".