18 posts • joined Saturday 16th July 2011 06:20 GMT
Re: Re. displays
This guy is a genius, I learned about this effect from him and he was the one who originally suggested hooking up a memristor to an EL panel as a brightness control.
Re. How did he die
The preliminary report seems to show he died of natural causes.
Possibly undiagnosed Long QT, as this can cause sudden cardiac death with little or no warning.
Even athletes have suffered from this, not so long ago it made the news after a footballer collapsed on the pitch from this affliction.
Sad news indeed, lets give the conspiracy theories a rest out of respect kthx.
Re: Battery hacks
Interestingly, this page http://ma.ecsdl.org/content/MA2012-02/8/664.full.pdf details just such a beast.
They are using liquid metal ie indium/calcium alloy electrodes to get around many of the passivation problems, so if the price of indium were to drop or another metal were substituted for indium such as sodium (liquid at high temperature) it should still work.
For certain uses a battery whose electrodes freeze at 5 Celsius wouldn't be a big problem, such as e-bikes where a few minutes use will warm them up nicely.
Worth a look, as copper PCB feedstock could be used as the base plates.
Also viable is to plate a transition layer onto a sheet of glass ie ITO, then vacuum deposit silver or copper over that so all those otherwise useless sheets of glass from broken flat screens could be recycled.
Also worth mentioning is that controllers have moved on a lot since 2012, the advent of single chip 16 pin FPGAs means very complex algorithms can be used to overcome nonlinearity with temperature and charge state and pressure feedback via BMP085 etc.
Has anyone here tried to DIY their own rechargeable batteries?
This covers:- buying "dead" packs on Ebay and reviving them, as well as scratch building cells.
I've heard that making lead acids is feasible but my latest research is into perfecting the calcium ion cell.
The plan here is to use calcium carbide, a known high energy compound familiar to cavers for lighting and convert it into a two stage electrochemical storage medium using intercalated graphite and iron phosphate.
The cell would consist of a CaC/C mix as the anode and FePO4 as the cathode which would then form the ion shuttle as in LiFePO4 technology.
It occurs to me that an electrolyte consisting of acetone and a few stabilisers would hold the acetylene stable until the cell is discharged; in its fully discharged state it would be essentially inert.
As the entire cell is anhydrous the reaction should be fully reversible and long term stable.
Acetone also happens to be relatively inexpensive though somewhat flammable but no more so than any other electrolyte commonly in use.
It has some useful properties such as dissolving acetylene so the cell would need to be minimally pressurised and in fact be ideal for high drain applications if failsafes are used.
I'm having issues getting the BaCO3 as (a) RM are getting twitchy about powdered chemicals in the post, and (b) the one and only supplier I found is on holiday.
Which leaves Sigma Aldritch, at least it will be NIST certified and known to be iron free.
Anyone here know of a source?
On the flip side, my graphite oxide showed up so thats 1/3 of the project ready to go.
Hi, I'm waiting on a few components, does anyone have a small desktop kiln they'd like to sell or trade please?
I've managed to source most of the chemicals, the BaCO3 is pyro grade but I've found a workaround to remove any ferrous contamination.
The really interesting work is dependent on a specific part which I've yet to source, but its well known and just a matter of waiting on the post or finding another supplier
Also useful would be an IR thermometer and/or a K thermocouple probe if anyone has a spare.
Kind regards, -Andre
Rumour has it
that this is why Solyndra and others bit the dust, not because they ran out of money but due to the pending lawsuits caused by airborne CIGS dust (cadmium is REALLY REALLY carcinogenic) and other toxic chemicals used in making solar panels incuding silane and trichloroethylene.
Was easier to pull the plug and blame the economy, than pay up.
Ask anyone who worked there, who is now suffering terribly because of corporate greed.
Don't even get me started on Area 51, that mess isn't going away any time soon.
The paints on the SR71 back in the 1980's were bad enough but the carbon composites are worse than asbestos and stealth paints use dibenzylfuran among other things which caused horrible side effects when burned on site.
Even more ideas
Its also feasible to make a small "blob" of low melting point gallium/indium alloy which melts at a relatively low temperature.
This is an order of magnitude more sensitive than the loop of nylon but has a breaking strain in the multiple kilos.
Also two electrically separate resistors, thyristors and batteries connected to the "base" means if one independent firing circuit breaks during ascent then the other should fire.
Use optical LM567 based triggering so no wire is needed, with the correct frequency being needed for it to fire.
As a second backup, have an altitude based trip which severs the connection to the balloon if the internal pressure exceeds a set limit, with three sets of rotors and a tilt sensor to keep the payload upright during descent so the rocket can fire.
What about a good old fashioned nylon thread looped around a ceramic resistor?
This has the advantage of working 100% once fired if a thyristor is used.
Also an interesting idea to add to the balloon is a high altitude UV radiation monitor made from a clear epoxy encased Bluray burner diode (LED'd ones work fine) connected to a small op-amp and voltage to frequency converter such as a 555.
These are pretty accurate and sensitive to wavelengths between 395 and 375nm (UV-A) so could be used as a primitive ozone depletion sensor.
Could be attached to either the primary or secondary payload and useful science done with it as long as it has been temperature/intensity calibrated on the ground.
Also worth considering, a VCSEL based (0.4mA) atmospheric dust sensor.
Adding solar cells to boost the onboard power might be feasible as the wafer type aren't that heavy and provide about 150mA at 1V per 20cm on a side piece.
Adding a WiFi tracker would also be useful in case the main transmitter breaks.
Use silver demister paint sprayed onto a prepared pizza base :-) use clingfilm held on the surface with PVA glue, or use thin copper tape.
This can double as a 10.250 GHz antenna as the wavelengths are compatible with both systems.
Tri-ox compound invented (Trek) ?
Based on haemoglobin extracted from expired blood stocks, however seems promising.
If pre-oxygenated it would certainly save lives, like a super transfusion without the volume and consequent blood pressure increase.
(IIRC blood isn't delivered oxygenated)
It would also work even with minimal/non existent pulse in conjunction with ECMO, as it delivers oxygen to ischaemic cells first.
Well our duty is now clear
To place Neil Armstrong's ashes on Mars, during the first manned mission.
Hopefully this will happen sooner rather than later, if NASA joins forces with the Chinese and Russian space agencies for a joint mission in the spirit of international cooperation.
Seem to recall reading somewhere about
A variant of pulse oximetry that measured blood glucose by sensing the slight change in differential absorption of red blood cells as glucose varies.
Seems that by compensating for the (large) change caused by blood oxygen concentration it is possible to calculate glucose level by measuring it with conventional stick sensors, at a range of blood oxygen levels.
Sounds doable, I think the problem here is that the changes involved are very small and significantly affected by skin density which changes by location etc.
Perhaps using something like an optical shunt (my idea) implanted through the skin in much the same way as the OOKP device used for repairing the eye.
-Andre (B.Sc hons Med Elect)
I discovered a while back that you can homebrew a relatively good alpha detector using:-
1 piece of pyrolytic graphite (Greedbay, £15)
1 cheap monochrome CMOS camera
A replacement crystal, I used a 4.43 MHz one robbed from a defunct TV
A tube of slow epoxy
A paif of gloves
1200 grit sandpaper
Silica gel granules
Black CD marker
All you do is thin down the PG (you can use the other bits for levitators, etc)
Once a good thin piece is obtained, sand it down to as thin as you can make it with 1200 grit.
Clean up with your favourite solvent to get rid of any carbon dust.
Dismantle your cheap CMOS camera (I used an old B&Q one) and then CAREFULLY remove the lid to expose the bare sensor with attached fine wires.
Epoxy around the edge so the wires are covered but not the sensor.
I found that positioning the sensor at a 20 degree angle for each section helped here.
I also advise putting a single small blob of silica gel on the edge with no contacts with an air path to the sensor as otherwise water vapour will ruin it in short order.
Allow to dry, then retest camera. If all well prepare another tiny drop of Epoxy.
If you wish you can also add a strip of Xray scintillator film onto the bottom edge of the chip with the light emitting side facing downwards.
Epoxy your PG sheet down and then dry the whole assembly out at 50 degrees for two hours.
Test camera, as you will need to determine where any light leaks are.
Then paint the Epoxy with Tippex, dry out and retest.
Overcoat with CD marker and then paint the back and edges of the board as well leaving a gap around the crystal.
I also tend to disable the automatic iris pin if present with a 1K resistor to Gnd.
If all is well, replace the 13.5 MHz crystal (or 16 MHz) with your 4.43 MHz one.
Test camera, you should not have stable video BUT it will work fine on a 'scope.
The alpha sensitivity should be approximately 2.8* efficiency with 13.5MHz (!)
Particles show up as vertical spikes on your scope display.
This is also theorised to work on linear CCDs from old printers!
Well maybe now people will listen
to Charles Shults of Xenotech Research.
He found evidence of fossils on Mars, which NASA actively tried to cover up by editing of photos.
No idea why NASA would go to such extremes to cover up something like this, but perhaps there are reasons that us mere mortals are not aware of.
The continued existence of bacteria on Mars is now more likely than ever, if it turns out that liquid water is indeed present.
In fact, fossils would last much longer on Mars due to the thin atmosphere, although you would expect some erosion due to the constant dust devils which have also been seen.
AC/DC although a lack of the latter scuppered Beagle 2
Isn't that expensive, I paid around £10 for 10 grams a year ago.
It IS messy stuff, gets everywhere. I found the best way to avoid this is to always handle it with gloves, and put it in a glass container.
The small amount of Ga-In I had left after my last experiment went awry went in said glass container and there is still about 0.3 grams left which is enough for dozens of experiments.
It also forms a nice alloy with copper while leaving the underlying surface intact so you can use a piece of protoboard of the solid tracks variety to make a duplicate of this experiment.
Silicone is best bought in the "acetoxy" variety as it doesen't contain acetic acid which would muck up the reaction. Its also probably not going to work without that special polymer, but Borax could work as a sub for the acid side at least and its easy to get hold of.
Some folks are making DIY ultracapacitors that last years so DIY memristors should be doable with some effort though you still have to refresh them as the "half life" is about 3 hours.
Simple timer and "copy location block A to location block B" should suffice, and you too can have your very own DIY megabyte sized memory that takes up about the same space as an Ipad2.
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