, which was arguably the very first electronic component specifically designed for use in computers. Most of the magic was in the ultra high purity nickel used in the cathode sleeve, to prevent interface formation and "sleeping sickness", which would result from even the slightest trace of silicon impurity in the nickel.
Every electronics geek needs one of these on their desk. Fortunately, there were millions made, and they come up on eBay cheap, as they have no value to the audiophools....
This was a major lesson that was learned during the early tube computer era. The best approach was NOT simply swapping out tubes after so many hours "to prevent in-service failures", but periodically running diagnostics checking pulse levels, etc.to identify tubes that were actually starting to slump off.
The failure rate vs life curve for most components (tubes included) has a high initial failure rate (so-called "infant mortality"), followed by a long period of low failure rates, which eventually trends upward at an increasing rate at end-of life. This produces a curve with a flat bottom and 2 peaks at the ends, like a cross-section of a bathtub.
By swapping out tubes before they hit the end of life, you push the entire tube complement in the equipment over toward the "infant mortality" end of the curve, actually INCREASING the failure rate over careful monitoring and replacing only those tubes that are actually starting to fail. All that tube swapping also results in increased failures through the increased handling of the glass tubes (breakage and seal leaks), wear on the sockets from pulling and inserting tubes, etc. The highest equipment uptime was achieved by not actually replacing tubes on a fixed schedule, but by overall system checks to identify and replace individual failing tubes BEFORE they progressed to the point of total failure.
Experience with electronic installations containing tens of thousands of tubes produced a huge amount of statistical data on component reliability, laying the foundations for modern reliability models and MTBF calculations.
A good read from 1960, when all this was being figured out is "Getting the Most out of Vacuum Tubes" by Bud Tomer, available on Archive.org:
A typical "rough service" incandescent lamp intended for use on 120V contains a filament actually designed for normal light output at 130V. By underheating the filament, the filament retains more strength when lit, and is better able to handle shock and vibration in hand-held worklights, etc.
Sold by 3M under the trade name "Fluorinert FC-43". Used primarily as a heat transfer fluid in exotic electronics.
The best known application to Slashdotters would be the Cray 2 supercomputer, which used a fluorinert "waterfall" to remove waste heat from the densely packed electronics. Some overclockers use it on high performance gaming rigs and the like, with the entire motherboard submerged in a bath of the stuff.
Because of the very high dielectric strength and low RF loss, it was used as a cooling medium in military radar gear, particularly airborne stuff.
Once you talk about making extracts (hash, hash oil, etc.) from your pound of weed, you move from "possession with intent to distribute", to "manufacturing of a controlled substance", the same charge that running a meth lab would get you.
Since you are now manufacturing, and not simply presumed to be selling, you move to the top of the food chain, and will make a great trophy for some ambitious narco-swine.
Rigol DS1052E--A "cheap and cheerful" Chinese import 50 MHz 2 channel DSO. A good general hobby scope, easily upgradeable to 100MHz bandwidth with a simple reflash of the firmware. Has a sizable following in the hardware hacker community because of the high "bang for the buck" factor.
Tektronix 7623: A 3-slot mainframe with 75 MHz bandwidth An 1969 vintage analog storage scope, which accepts various interchangeable plug in units to give a huge range of features. Actually has an on-screen display for V/div and Time/div, which was bleeding edge stuff at the time it was introduced.
Tektronix 453: A 1963 vintage portable field service scope (designed for servicing IBM mainframes). Dual channel, 50 MHz. Built to take constant abuse and just keep working. Still a VERY usable scope for general purposes, and has the sharpest brightest trace of any scope I have ever used.
It's embarassing b/c essentially its the same thing as that plastic mold machine at tourist attractions that can make you a plastic souvenier of the Washington Monument.
At least those "mold-a-rama" machines demonstrate real-world manufacturing techniques. There are a hell of a lot more injection molding machines out there cranking out parts than there are 3D printers, that's for sure.
that doesn't mean a thing to rocket hobbyists here.
As long as you are using it "for sporting, cultural or recreational purposes in antique firearms", you can purchase and possess up to 50 pounds of black powder, with no federal requirement as to proper storage, etc. 50 pounds of black powder is far more than enough to level a typical house, especially if it goes off in the basement.
If you want to use a few grams of the stuff for rocketry purposes (igniters, squibs, parachute ejection charges, etc.), you need to get a Low Explosives Users Permit (LEUP) from the BATFE, consent to regular government inspections, and provide secured storage, in an approved magazine. You also need to have a large enough piece of property to keep that few grams of powder at least 75 feet from your neighbors, get local fire marshal/police/neighbors signoff, etc, before the LEUP is issued.
Again, use it in a gun, do whatever you want more or less. Use it to deploy safety devices in a rocket, submit to a federal anal probe.
Yes, there are ways around this BS (using pyrodex or smokeless powder rather than real black powder), but those come with additional technical issues, which may make safe rocket recovery more difficult than it needs to be.
Of course they do. Schooling is easy to just "check off the boxes", and even verify with a simple phone call. Education, not so much.
Evaluating whether or not an applicant actually has the requisite knowledge and skills for the position would require them to actually do their jobs, including understanding (at least at a meta-level) exactly what the position entails and what skills are actually relevant.
Slashdot Mirror
, which was arguably the very first electronic component specifically designed for use in computers. Most of the magic was in the ultra high purity nickel used in the cathode sleeve, to prevent interface formation and "sleeping sickness", which would result from even the slightest trace of silicon impurity in the nickel.
http://www.radiomuseum.org/tubes/tube_7ak7.html
Every electronics geek needs one of these on their desk. Fortunately, there were millions made, and they come up on eBay cheap, as they have no value to the audiophools....
This was a major lesson that was learned during the early tube computer era. The best approach was NOT simply swapping out tubes after so many hours "to prevent in-service failures", but periodically running diagnostics checking pulse levels, etc.to identify tubes that were actually starting to slump off.
The failure rate vs life curve for most components (tubes included) has a high initial failure rate (so-called "infant mortality"), followed by a long period of low failure rates, which eventually trends upward at an increasing rate at end-of life. This produces a curve with a flat bottom and 2 peaks at the ends, like a cross-section of a bathtub.
By swapping out tubes before they hit the end of life, you push the entire tube complement in the equipment over toward the "infant mortality" end of the curve, actually INCREASING the failure rate over careful monitoring and replacing only those tubes that are actually starting to fail. All that tube swapping also results in increased failures through the increased handling of the glass tubes (breakage and seal leaks), wear on the sockets from pulling and inserting tubes, etc. The highest equipment uptime was achieved by not actually replacing tubes on a fixed schedule, but by overall system checks to identify and replace individual failing tubes BEFORE they progressed to the point of total failure.
Experience with electronic installations containing tens of thousands of tubes produced a huge amount of statistical data on component reliability, laying the foundations for modern reliability models and MTBF calculations.
A good read from 1960, when all this was being figured out is "Getting the Most out of Vacuum Tubes" by Bud Tomer, available on Archive.org:
https://archive.org/details/GettingTheMostOutOfVacuumTubes_105
Make sure that you keep that cord coiled up into a nice tight ball, too...
Now uses a conventional heating element, rather than a 100W bulb:
http://articles.latimes.com/2011/feb/23/business/la-fi-easy-bake-20110223
A typical "rough service" incandescent lamp intended for use on 120V contains a filament actually designed for normal light output at 130V. By underheating the filament, the filament retains more strength when lit, and is better able to handle shock and vibration in hand-held worklights, etc.
This negatively impacts efficiency, though.
Sold by 3M under the trade name "Fluorinert FC-43". Used primarily as a heat transfer fluid in exotic electronics.
The best known application to Slashdotters would be the Cray 2 supercomputer, which used a fluorinert "waterfall" to remove waste heat from the densely packed electronics. Some overclockers use it on high performance gaming rigs and the like, with the entire motherboard submerged in a bath of the stuff.
Because of the very high dielectric strength and low RF loss, it was used as a cooling medium in military radar gear, particularly airborne stuff.
and used by a few overclockers with full-immersion cooling systems.
How long until the DEA makes these things illegal?
Just say NO to absolute silence.....
Apollo 16 brought a UV telescope along with them...
http://en.wikipedia.org/wiki/Far_Ultraviolet_Camera/Spectrograph
Once you talk about making extracts (hash, hash oil, etc.) from your pound of weed, you move from "possession with intent to distribute", to "manufacturing of a controlled substance", the same charge that running a meth lab would get you.
Since you are now manufacturing, and not simply presumed to be selling, you move to the top of the food chain, and will make a great trophy for some ambitious narco-swine.
http://en.wikipedia.org/wiki/HIV_superinfection
From newest to oldest:
Rigol DS1052E--A "cheap and cheerful" Chinese import 50 MHz 2 channel DSO. A good general hobby scope, easily upgradeable to 100MHz bandwidth with a simple reflash of the firmware. Has a sizable following in the hardware hacker community because of the high "bang for the buck" factor.
Tektronix 7623: A 3-slot mainframe with 75 MHz bandwidth An 1969 vintage analog storage scope, which accepts various interchangeable plug in units to give a huge range of features. Actually has an on-screen display for V/div and Time/div, which was bleeding edge stuff at the time it was introduced.
Tektronix 453: A 1963 vintage portable field service scope (designed for servicing IBM mainframes). Dual channel, 50 MHz. Built to take constant abuse and just keep working. Still a VERY usable scope for general purposes, and has the sharpest brightest trace of any scope I have ever used.
It's embarassing b/c essentially its the same thing as that plastic mold machine at tourist attractions that can make you a plastic souvenier of the Washington Monument.
At least those "mold-a-rama" machines demonstrate real-world manufacturing techniques. There are a hell of a lot more injection molding machines out there cranking out parts than there are 3D printers, that's for sure.
anything else that might offend somebody....
Piss poor idea or not?
http://science.slashdot.org/story/07/08/22/2225225/drug-testing-entire-cities-at-once
...an agency of the UNITED NATIONS.
http://en.wikipedia.org/wiki/World_Health_Organization
You can in Colorado...
http://www.denverpost.com/breakingnews/ci_24259474/colorado-farmer-harvests-first-u-s-commercial-hemp
presumably, the shooters have all fires rifles previously, and would surely notice the difference in recoil between a bullet and a blank round.
In this particular case, I doubt it.
Propofol isn't a controlled substance under the CSA.
that doesn't mean a thing to rocket hobbyists here.
As long as you are using it "for sporting, cultural or recreational purposes in antique firearms", you can purchase and possess up to 50 pounds of black powder, with no federal requirement as to proper storage, etc. 50 pounds of black powder is far more than enough to level a typical house, especially if it goes off in the basement.
If you want to use a few grams of the stuff for rocketry purposes (igniters, squibs, parachute ejection charges, etc.), you need to get a Low Explosives Users Permit (LEUP) from the BATFE, consent to regular government inspections, and provide secured storage, in an approved magazine. You also need to have a large enough piece of property to keep that few grams of powder at least 75 feet from your neighbors, get local fire marshal/police/neighbors signoff, etc, before the LEUP is issued.
Again, use it in a gun, do whatever you want more or less. Use it to deploy safety devices in a rocket, submit to a federal anal probe.
Yes, there are ways around this BS (using pyrodex or smokeless powder rather than real black powder), but those come with additional technical issues, which may make safe rocket recovery more difficult than it needs to be.
Of course they do. Schooling is easy to just "check off the boxes", and even verify with a simple phone call. Education, not so much.
Evaluating whether or not an applicant actually has the requisite knowledge and skills for the position would require them to actually do their jobs, including understanding (at least at a meta-level) exactly what the position entails and what skills are actually relevant.
Buzz wasn't selected until 1963, as part of the 3rd group of astronauts.
The last survivor of the original 7 is John Glenn...
The IATA identifier (and VOR beacon) for Pearson intl. airport, Toronto.
And the title of a kick-ass instrumental by the Canadian rock band Rush:
http://en.wikipedia.org/wiki/YYZ_(instrumental)
Rush fan, huh?