Good point. this device claims 30 keV minimum gamma energy, so it would see the 60 keV ray. FWIW, that unit claims minimum alpha energy of 4 MeV, so it'd see the alphas, too.
Am-241 emits low energy gamma rays of 60 keV. The Am-241 gamma dose constant of 3.14 x 10-9 Sv m2 h-1 Ci-1 gives an annual dose at one metre of 27 Sv/yr for an average household smoke detector - around 100 times lower than the dose from natural background radiation.
Using solar is a good idea, but there are monofuels/monopropellants out there - IIRC nitromethane ('top fuel' dragster' use it, but with added O2) can be coaxed into burning without additional oxidizers. So can hydrazine, but that's fairly nasty stuff. NASA, et al use it currently for small thrusters.
Bad advice - nearly all Geiger counters (true Geiger counters - those with GM tubes) are completely insensitive to alpha radiation - the window that allows radiation in while maintaining the vacuum is too thick to allow alpha in. Additionally, the mean path length of alpha in air is only a few cm, so you have to be right on the source to get a reading at all, even if you counter is sensitive.
Once you get the counts, wait a while and retest to get the half life and try to see what the source may be.
Often the isotope in question can be determined by the emission spectrum using gamma spectroscopy - no need to wait a half life. If that were true, we'd still be waiting to verify the discovery of most of the isotopes of Uranium and Plutonium.
How about using a salt substitute, which is almost pure KCl? That works a lot better. Much higher activity, and the amount of K present is easy to calculate.
X-10, Z-Wave and Insteon are all also equally incorrect in that they generally put the control at the point of the switch, instead of the fixture.
The control point is at the switch because that's where a human can most easily interact with the device, and that's where always-on power is located (legacy wiring). I agree that the best of all worlds would be power wired only to the fixtures and that any human switches are ZigBee/Z-Wave/whatever and can be stuck on the wall with velcro(tm)/carried around/etc. The savings in copper alone would be huge.
I like the idea of the APT tax, but what about cash? Would that be eliminated under this system? I think people would being using cash quite heavily if they could avoid the 0.3% tax.
That reminds me of a bit in one of the control registers on the original IBM PC/AT motherboard. It's function: Mask the non-maskable interrupt. That's kinda like dreaming the impossible dream, isn't it?
Fukushima has spit out about 130-150 PBq of iodine-131...
All radiation is not created equal, however. All of that Iodine-131 you're so worried about? Only 0.5% of it remains in the environment at this point. I-131's half-life is only 8 days. Assuming that all of it was released at the beginning of the accident (not true, but handy nonetheless) it's now 60 days (7.5 half lives) after the start of the accident. (0.5) ^ (60/8) =.0055, or 0.55%. Even if we assume that the release occurred effectively 30 days ago, we're still only looking at 7.4% of it still around. After a year, 1.84 x 10 ^ -12 percent will remain - out of each PBq emitted, 184 radioactive atoms will remain.
The radiation released from coal plants is mostly naturally occurring Uranium and Thorium, both of which have very long half lives, which means that although their radioactive activity level may be low and therefore represent a relatively minor radiological hazard, their chemical properties remain to poison people as any other heavy metal.
The hyperbole of "dangerous levels of radiation" came from you, not the original article. The actual quote was, "...samples of seaweed taken from as far as 40 miles of the Fukushima plant had been found to contain radiation well above legal limits. Of the 22 samples tested, ten were contaminated with five times the legal limit of iodine 131 and 20 times of caesium 137." [emphasis mine].
The legal limits of radiation are so very low that even the 5x dose of iodine is still likely not dangerous. In fact, wait 24 days (3 half-lives) and you'll be under the limit. The cesium is a bit more troubling as its half-life is more like 30 years, although it's biological half-life is more like 70 days.
I assume the 'legal limit' mentioned in the article is the lower, more conservative non-nuclear worker limit. The US limits for cesium 137 are 1mSv/yr for non-nuclear workers and 50 mSv/yr (max 100 mSv over 5 years) for nuclear workers. If a nuclear worker can handle 50x the non-nuclear limit for two years out of five or 20 mSv/yr every year indefinitely, I'm sure members of the public will be ok at that dose, too.
Yes, but we're a secondary allocation over most if not all of the 70cm band, and must accept 'interference' from primary allocation users. Jamming them is illegal. If you were in the rest of the world, 433 MHz is an ISM band.
Government agencies are not beholden to the FCC - that's for us peons. They have the NTIA, which does essentially the same thing as the FCC, but for the federales. In the rest of the world, 433MHz is an ISM band. Here in the US we see importers trying to get the FCC to allow those ISM devices into the US - no thanks! They will crush the Amateur 70cm band.
That frequency is smack-dab in the middle of an Amateur Radio band (secondary allocation), and is also used by the feds for 'radiolocation'. See page 491 of this PDF for the allocations. Also look at the footnotes - the interesting one is G8 - "Low power Federal radio control operations are permitted in the band 420–450 MHz."
I'm curious about the actual operation of this device - since the 433 MHz transmitter is low power, There are three choices I can think of:
1) The device transmits blindly and there a network of receivers/repeaters deployed that we the people don't know about. 2) The unit is interrogated individually for a data dump. This implies that an FBI agent has to be relatively close to the car to read the data. 3) The device only listens on 433 MHz for commands to turn on/off logging, and the data dump is done on retrieval of the device.
I was at BEA World in San Diego years ago, and one of the presenters for a JMX topic was extolling the virtues of "Gwadge Beans". It took me a while to realize he'd learned 'Gauge' as 'Guage'.
Even without obvious booby-traps, criminals have won lawsuits for falling down stairs and stepping on skateboards _in their victim's house_. How idiotic is that? In Virginia, I can shoot an armed intruder graveyard dead if my life's in danger, but if his life is in danger from his own clumsiness somehow I'm responsible???
Do what a friend of mine did back in high school. Sadly, this would be illegal today.
1) Get 20 large, insanely sharp fish hooks 2) Attach their eyelets together tightly with steel leader so that the hooks form a ball. 3) Place the ball-o-fishhooks under the dashboard where the thief will have to reach to disconnect wires. 4) Bolt the other end of steel leader to something very strong under the dash. 5) Place a towel on the carpet under the ball-o-fishhooks to catch the blood. 6) Call the cops if the thief doesn't get free, giggle a little if he does. 7) Replace towel.
I think your 2nd and 3rd assertions are false, however the first one has an interesting side note. Ever heard of a PET scan? That's antimatter - Positron Emission Tomography. That nasty radioactive Potassium in bananas, 40K? It emits positrons (B+ decay) approximately 11% of the time. From this article: "In a human body of 70 kg mass, about 4,400 nuclei of 40K decay per second." That's 484 positrons/sec being annihilated within your body! Antimatter is all around us.
Children fat, aka depot fat, is well-studied. Here's a PDF that compares various types of fat/lipid. Our fat is approximately 47% oleic acid and 24% palmitic - no wonder I love the Caribbean! Here's a PDF of all sorts of details.
That's essentially what I said in the other reply. What you're saying is that the columns in the table can have different bases - I say they can't. You'd end up having what scientists call 'mixed units' - definitely bad juju. You're conflating counting minutes, for example, with the expression of hours and minutes (counting vs grouping). I _count_ minutes in decimal, octal, hex, binary, whatever just as a Babylonian would count them in their base 60 system. From 9 decimal, I increment to 10 decimal. The babylonian would go from whatever their symbol for 59 was to whatever their symbol for 1 was, plus their placeholder for 'nothing'. In hex I'd go from 15 decimal minutes (denoted 'F') to sixteen minutes (denoted as '10').
If you want to group minutes into hours and remaining minutes, that's where you get into modulo arithmetic and grouping. 75 minutes is (75 div 60) hours plus (75 mod 60) minutes. No base conversion, nothing more complicated than grouping via modular arithmetic.
In Spanish, the words for 11 thru 15 are once doce, trece, catorce, quince. Only when you get to 16 do you start the 'ten and six' counting style. Does that mean the early Spaniards were base 15? No. Again, the BASE of a counting system is the number, when raised to the power of the digit's zero-based position, that gives the numerical value of that position. 10^0 = 1, 10^1=10, 10^2 = 100, etc. For binary (base 2) , 2^0, 2^1, 2^2, etc.
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Hell is also a tropical paradise on Grand Cayman. My wife and I were married not far from there, and in fact went thru Hell to get married.
Good point. this device claims 30 keV minimum gamma energy, so it would see the 60 keV ray. FWIW, that unit claims minimum alpha energy of 4 MeV, so it'd see the alphas, too.
Interesting quote from here:
Am-241 emits low energy gamma rays of 60 keV. The Am-241 gamma dose constant of 3.14 x 10-9 Sv m2 h-1 Ci-1 gives an annual dose at one metre of 27 Sv/yr for an average household smoke detector - around 100 times lower than the dose from natural background radiation.
Could you really detect that above background?
Using solar is a good idea, but there are monofuels/monopropellants out there - IIRC nitromethane ('top fuel' dragster' use it, but with added O2) can be coaxed into burning without additional oxidizers. So can hydrazine, but that's fairly nasty stuff. NASA, et al use it currently for small thrusters.
Bad advice - nearly all Geiger counters (true Geiger counters - those with GM tubes) are completely insensitive to alpha radiation - the window that allows radiation in while maintaining the vacuum is too thick to allow alpha in. Additionally, the mean path length of alpha in air is only a few cm, so you have to be right on the source to get a reading at all, even if you counter is sensitive.
Once you get the counts, wait a while and retest to get the half life and try to see what the source may be.
Often the isotope in question can be determined by the emission spectrum using gamma spectroscopy - no need to wait a half life. If that were true, we'd still be waiting to verify the discovery of most of the isotopes of Uranium and Plutonium.
How about using a salt substitute, which is almost pure KCl? That works a lot better. Much higher activity, and the amount of K present is easy to calculate.
You can easily cut gears on a lathe. The one my father owns even has auto-indexing so that it turns the stock as it passes by the cutter.
X-10, Z-Wave and Insteon are all also equally incorrect in that they generally put the control at the point of the switch, instead of the fixture.
The control point is at the switch because that's where a human can most easily interact with the device, and that's where always-on power is located (legacy wiring). I agree that the best of all worlds would be power wired only to the fixtures and that any human switches are ZigBee/Z-Wave/whatever and can be stuck on the wall with velcro(tm)/carried around/etc. The savings in copper alone would be huge.
Miguel's obsession with creating an open source version of .NET borders on mono-mania.
I like the idea of the APT tax, but what about cash? Would that be eliminated under this system? I think people would being using cash quite heavily if they could avoid the 0.3% tax.
That reminds me of a bit in one of the control registers on the original IBM PC/AT motherboard. It's function: Mask the non-maskable interrupt. That's kinda like dreaming the impossible dream, isn't it?
Fukushima has spit out about 130-150 PBq of iodine-131 ...
All radiation is not created equal, however. All of that Iodine-131 you're so worried about? Only 0.5% of it remains in the environment at this point. I-131's half-life is only 8 days. Assuming that all of it was released at the beginning of the accident (not true, but handy nonetheless) it's now 60 days (7.5 half lives) after the start of the accident. (0.5) ^ (60/8) = .0055, or 0.55%. Even if we assume that the release occurred effectively 30 days ago, we're still only looking at 7.4% of it still around. After a year, 1.84 x 10 ^ -12 percent will remain - out of each PBq emitted, 184 radioactive atoms will remain.
The radiation released from coal plants is mostly naturally occurring Uranium and Thorium, both of which have very long half lives, which means that although their radioactive activity level may be low and therefore represent a relatively minor radiological hazard, their chemical properties remain to poison people as any other heavy metal.
The hyperbole of "dangerous levels of radiation" came from you, not the original article. The actual quote was, "...samples of seaweed taken from as far as 40 miles of the Fukushima plant had been found to contain radiation well above legal limits. Of the 22 samples tested, ten were contaminated with five times the legal limit of iodine 131 and 20 times of caesium 137." [emphasis mine].
The legal limits of radiation are so very low that even the 5x dose of iodine is still likely not dangerous. In fact, wait 24 days (3 half-lives) and you'll be under the limit. The cesium is a bit more troubling as its half-life is more like 30 years, although it's biological half-life is more like 70 days.
I assume the 'legal limit' mentioned in the article is the lower, more conservative non-nuclear worker limit. The US limits for cesium 137 are 1mSv/yr for non-nuclear workers and 50 mSv/yr (max 100 mSv over 5 years) for nuclear workers. If a nuclear worker can handle 50x the non-nuclear limit for two years out of five or 20 mSv/yr every year indefinitely, I'm sure members of the public will be ok at that dose, too.
Note that the naturally-occurring background radiation level varies by a factor of over 200 with no apparent negative effects, and possibly positive effects.
Aerogels are also quite fragile, so in all likelihood the reentry pressures would fragment them quite well.
Yes, but we're a secondary allocation over most if not all of the 70cm band, and must accept 'interference' from primary allocation users. Jamming them is illegal. If you were in the rest of the world, 433 MHz is an ISM band.
Government agencies are not beholden to the FCC - that's for us peons. They have the NTIA, which does essentially the same thing as the FCC, but for the federales. In the rest of the world, 433MHz is an ISM band. Here in the US we see importers trying to get the FCC to allow those ISM devices into the US - no thanks! They will crush the Amateur 70cm band.
That frequency is smack-dab in the middle of an Amateur Radio band (secondary allocation), and is also used by the feds for 'radiolocation'. See page 491 of this PDF for the allocations. Also look at the footnotes - the interesting one is G8 - "Low power Federal radio control operations are permitted in the band 420–450 MHz."
I'm curious about the actual operation of this device - since the 433 MHz transmitter is low power, There are three choices I can think of:
1) The device transmits blindly and there a network of receivers/repeaters deployed that we the people don't know about.
2) The unit is interrogated individually for a data dump. This implies that an FBI agent has to be relatively close to the car to read the data.
3) The device only listens on 433 MHz for commands to turn on/off logging, and the data dump is done on retrieval of the device.
Ideas?
I was at BEA World in San Diego years ago, and one of the presenters for a JMX topic was extolling the virtues of "Gwadge Beans". It took me a while to realize he'd learned 'Gauge' as 'Guage'.
Even without obvious booby-traps, criminals have won lawsuits for falling down stairs and stepping on skateboards _in their victim's house_. How idiotic is that? In Virginia, I can shoot an armed intruder graveyard dead if my life's in danger, but if his life is in danger from his own clumsiness somehow I'm responsible???
"lightening" is what cream does to coffee. Lightning is electricity from the sky.
Do what a friend of mine did back in high school. Sadly, this would be illegal today.
1) Get 20 large, insanely sharp fish hooks
2) Attach their eyelets together tightly with steel leader so that the hooks form a ball.
3) Place the ball-o-fishhooks under the dashboard where the thief will have to reach to disconnect wires.
4) Bolt the other end of steel leader to something very strong under the dash.
5) Place a towel on the carpet under the ball-o-fishhooks to catch the blood.
6) Call the cops if the thief doesn't get free, giggle a little if he does.
7) Replace towel.
I think your 2nd and 3rd assertions are false, however the first one has an interesting side note. Ever heard of a PET scan? That's antimatter - Positron Emission Tomography. That nasty radioactive Potassium in bananas, 40K? It emits positrons (B+ decay) approximately 11% of the time. From this article: "In a human body of 70 kg mass, about 4,400 nuclei of 40K decay per second." That's 484 positrons/sec being annihilated within your body!
Antimatter is all around us.
We're already generating massive neutrino beams as a result of employing nuclear fission for energy production. We've also detected our own beams shining through the earth.
Children fat, aka depot fat, is well-studied. Here's a PDF that compares various types of fat/lipid. Our fat is approximately 47% oleic acid and 24% palmitic - no wonder I love the Caribbean! Here's a PDF of all sorts of details.
That's essentially what I said in the other reply. What you're saying is that the columns in the table can have different bases - I say they can't. You'd end up having what scientists call 'mixed units' - definitely bad juju. You're conflating counting minutes, for example, with the expression of hours and minutes (counting vs grouping). I _count_ minutes in decimal, octal, hex, binary, whatever just as a Babylonian would count them in their base 60 system. From 9 decimal, I increment to 10 decimal. The babylonian would go from whatever their symbol for 59 was to whatever their symbol for 1 was, plus their placeholder for 'nothing'. In hex I'd go from 15 decimal minutes (denoted 'F') to sixteen minutes (denoted as '10').
If you want to group minutes into hours and remaining minutes, that's where you get into modulo arithmetic and grouping. 75 minutes is (75 div 60) hours plus (75 mod 60) minutes. No base conversion, nothing more complicated than grouping via modular arithmetic.
In Spanish, the words for 11 thru 15 are once doce, trece, catorce, quince. Only when you get to 16 do you start the 'ten and six' counting style. Does that mean the early Spaniards were base 15? No. Again, the BASE of a counting system is the number, when raised to the power of the digit's zero-based position, that gives the numerical value of that position. 10^0 = 1, 10^1=10, 10^2 = 100, etc. For binary (base 2) , 2^0, 2^1, 2^2, etc.
The babylonians had a real Base 60 system.