It is believed that the probable cause of the accident was the shorting of the accessory connectors when they touched against a metal clip, tools on the miner's belt or with the metal duplex wire spool. This in turn activated a "Man Down" high energy signal burst of 4.56 watts. It was demonstrated that sufficient RF energy could be coupled into the electric detonator circuit to heat the bridge wire to ignition with 4.56 watts of power only 8 feet away with the antenna touching or near the duplex wire.
"It should be noted that blasting industry standards recommend a minimum standoff safety distance of 10 feet for a radio transmitter operating at 400 megahertz and 5 watts. (IME 20) This standard was written many years ago and is based on older electric blasting cap bridge wire circuit designs. With today's more sensitive electric blasting cap bridge wire circuits, it would be prudent and advisable to double this distance."
Re:O'Reilly art Creative Commons licensed?
on
Laser Etching a Laptop
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· Score: 4, Informative
The artwork was originally from a Dover book. Dover publishes books full of public domain art, along with their reprints of classic and out-of-print textbooks.
Planets aren't static points, they are in a constant state of motion. Spacecraft don't travel in straight lines, that would require insane amounts of energy. The trick is to get from point A to point B in a reasonable amount of time without an excessive expenditure of energy. See Hohmann transfer orbit.
It used to be common for PCs. I can remember ordering a computer and being quoted a delivery date that included time for the assembly of the computer and 24 hours of burn-in testing. I don't know how many vendors still do that.
Popular attitudes towards financial crimes, and criminals, must change in Nigeria. See Nkem Owoh's hit video "I Go Chop Your Dollar" for an example of this problem.
That's assuming both cylinders were recordings of the same performance. From some of the old photographs that I've seen of the recording sessions, it looks like each performance produced a limited number of cylinders. If you wanted more cylinders, you recorded another performance.
That's true if the outside temperature is sufficiently low. It becomes a problem when you have to cool the building and each watt wasted is an additional burden on the cooling system. Many modern buildings are uninhabitable if the HVAC (heating, ventilation, air-conditioning) system fails, even in moderate weather.
I've read several stories about parasites that affect the behavior of their host. The host's behavior is changed in a way that increases the likelihood that it will be eaten by a predator, perpetuating the life-cycle of the parasite. Dicrocoelium dendriticum causes ants to climb to the tops of blades of grass, waiting to be eaten by the next convenient herbivore.
You are assuming that there are infinite resources. Suppose there is a screening test that is 95% accurate, but it costs $1000. The cheap screening test is only 70% accurate, but it costs $10. If we have a limited budget for testing, using both tests is more efficient. It costs an average of $310 per person instead of $1000 per person. The number of false positives could be reduced by screening for risk factors before doing any testing.
What if I developed a cheap blood test for breast cancer that was 70% accurate? Would you also call it a fraud? It could be a medically useful screening test, even if its accuracy was less than desired. Positive test results would trigger additional screening with more accurate, and more expensive, tests.
I don't have a problem with polygraphs, or other stress tests, as long as the people doing the testing are properly trained and recognize the limitations of the test. Flunking a polygraph isn't proof of anything, but it does provide useful information.
Your numbers, and the implied equation are incorrect. Air doesn't have "resistance" to EM radiation. There is an absorption factor that is frequency dependent. At the frequencies in question, absorption is minimal. Field strength is inversely proportional to the square of the distance.
Free Space Loss (in dB) = 20 * Log10 (frequency in MHz) + 20 * Log10 (Distance in Miles) + 36.6
No matter how bad a movie is, it could always have been much worse. That big budget allows you to hire people who are good at what they do, build sets that don't look like shit, and have decent production values. It's no guarantee of a great movie, but it isn't likely to be a total waste of film.
If you read the movie industry trade rags, you'll discover that the shlock in the theaters is actually the cream of the crop. A movie has to met some standards to get wide theatrical release. There are many low-budget movies that go straight to video, cable or foreign distribution.
One of the big problems would be voltage regulation. Most electronics devices would require local DC/DC convertors to provide regulated DC power to their circuits. So you still have a zillion individual power supplies, the only difference is that they get bulk power from a DC feed instead of an AC feed.
I doubt many people would be happy with the large copper bus bars that would be needed to distribute low voltage DC at any reasonable power level.
The problem is navigation. If I am using a sextant and a clock (chronometer or shortwave radio tuned to WWV) to determine my longitude, I need a time source that is kept in close synchronization with the actual rotation of the Earth.
They tried using a "rubber second" (variable length second) back in the 1960s. It was a disaster. There are too many things that are based on the length of a second.
Slashdot Mirror
Not on game consoles. The markup is almost zero.
I prefer to get my safety information from engineers, not random "experts".
See A Guide to Radio Frequency Hazards with Electric Detonators (PDF).
Humidity control.
The artwork was originally from a Dover book. Dover publishes books full of public domain art, along with their reprints of classic and out-of-print textbooks.
Planets aren't static points, they are in a constant state of motion. Spacecraft don't travel in straight lines, that would require insane amounts of energy. The trick is to get from point A to point B in a reasonable amount of time without an excessive expenditure of energy. See Hohmann transfer orbit.
It used to be common for PCs. I can remember ordering a computer and being quoted a delivery date that included time for the assembly of the computer and 24 hours of burn-in testing. I don't know how many vendors still do that.
Popular attitudes towards financial crimes, and criminals, must change in Nigeria. See Nkem Owoh's hit video "I Go Chop Your Dollar" for an example of this problem.
That's assuming both cylinders were recordings of the same performance. From some of the old photographs that I've seen of the recording sessions, it looks like each performance produced a limited number of cylinders. If you wanted more cylinders, you recorded another performance.
That's true if the outside temperature is sufficiently low. It becomes a problem when you have to cool the building and each watt wasted is an additional burden on the cooling system. Many modern buildings are uninhabitable if the HVAC (heating, ventilation, air-conditioning) system fails, even in moderate weather.
I've read several stories about parasites that affect the behavior of their host. The host's behavior is changed in a way that increases the likelihood that it will be eaten by a predator, perpetuating the life-cycle of the parasite. Dicrocoelium dendriticum causes ants to climb to the tops of blades of grass, waiting to be eaten by the next convenient herbivore.
You are assuming that there are infinite resources. Suppose there is a screening test that is 95% accurate, but it costs $1000. The cheap screening test is only 70% accurate, but it costs $10. If we have a limited budget for testing, using both tests is more efficient. It costs an average of $310 per person instead of $1000 per person. The number of false positives could be reduced by screening for risk factors before doing any testing.
I don't have a problem with polygraphs, or other stress tests, as long as the people doing the testing are properly trained and recognize the limitations of the test. Flunking a polygraph isn't proof of anything, but it does provide useful information.
Didn't that system use 60-bit words? I had some data format requirements from a CDC 6X00 site that packed everything into blocks of 60-bit words.
Free Space Loss (in dB) = 20 * Log10 (frequency in MHz) + 20 * Log10 (Distance in Miles) + 36.6
The problem is that it doesn't work with plutonium (high level of background neutrons) and it has severe safety issues (accidental criticality).
No matter how bad a movie is, it could always have been much worse. That big budget allows you to hire people who are good at what they do, build sets that don't look like shit, and have decent production values. It's no guarantee of a great movie, but it isn't likely to be a total waste of film.
If you read the movie industry trade rags, you'll discover that the shlock in the theaters is actually the cream of the crop. A movie has to met some standards to get wide theatrical release. There are many low-budget movies that go straight to video, cable or foreign distribution.
There is no silver bullet!
If you still don't understand it, go to step one.
I don't think there are any patents on Chobham armor. The design of the armor is a military secret.
I doubt many people would be happy with the large copper bus bars that would be needed to distribute low voltage DC at any reasonable power level.
I think it was originally a proposal from the U.S. Naval Observatory.
The problem is navigation. If I am using a sextant and a clock (chronometer or shortwave radio tuned to WWV) to determine my longitude, I need a time source that is kept in close synchronization with the actual rotation of the Earth.
They tried using a "rubber second" (variable length second) back in the 1960s. It was a disaster. There are too many things that are based on the length of a second.