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#21
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Use a radioactive eyepiece!
On Jan 30, 8:46*pm, Quadibloc wrote:
On Jan 30, 5:22*pm, RichA wrote: The Kodak Ektamate and Ektar lenses all use thorium glass. *Pretty harmless just sitting around but I wouldn't want to press my eye to one for any length of time. http://www.surplusshed.com/pages/item/l3759.html There once were some World War II lenses that used radioactive glass, but that is long gone. Any surplus from the days of digital Group III fax machines would not use lenses made from that kind of glass - because the glass isn't made any more. I see that some radioactive glass was used even in the 1960s, so I'm mistaken... http://www.bnphoto.org/bnphoto/LostS...adioactive.htm John Savard |
#22
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Use a radioactive eyepiece!
"Quadibloc" wrote in message
... On Jan 30, 8:46 pm, Quadibloc wrote: On Jan 30, 5:22 pm, RichA wrote: The Kodak Ektamate and Ektar lenses all use thorium glass. Pretty harmless just sitting around but I wouldn't want to press my eye to one for any length of time. http://www.surplusshed.com/pages/item/l3759.html There once were some World War II lenses that used radioactive glass, but that is long gone. Any surplus from the days of digital Group III fax machines would not use lenses made from that kind of glass - because the glass isn't made any more. I see that some radioactive glass was used even in the 1960s, so I'm mistaken... http://www.bnphoto.org/bnphoto/LostS...adioactive.htm John Savard ================================================= Good that you can admit it, Savard. It's really quite painless, isn't it? Nobody is going to beat you to death over it now. You are mistaken about relativity, too, but that's because you are hopeless at algebra. Your pal Bill Owen hasn't come to your rescue, either. He's gone away to think about it. He's only been gone three weeks. Perhaps he's gone away to forget about it. "Quadibloc" wrote in message ... (begin quote) At the end of Section 3 we find the transformation derived: tau=beta(t-vx/c^2), xi=beta(x-vt), eta=y, zeta=z, where beta=1/sqrt(1-v^2/c^2). With trivial algebraic manipulation we can derive the inverse transformation: t=beta(tau+v(xi)/c^2), x=beta(xi+v(tau)), y=eta, z=zeta. (end quote) =============================================== Not only is Savard hopeless at simple algebra, he quotes the drool of some unnamed moron who is equally hopeless. Perhaps he can show, step-by-step, his trivial derivation, like this: xi = beta(x-vt) Divide both sides of the equation by beta xi/beta = beta(x-vt)/beta Since beta/beta = 1, xi/beta = 1*(x-vt) Add vt to both sides of the equation xi/beta +vt = (x-vt)+vt Since vt - vt = 0, x = xi/beta +vt Why is Savard multiplying xi by beta instead of dividing? -- This message is brought to you from the keyboard of Lord Androcles, Zeroth Earl of Medway. When I get my O.B.E. I'll be an earlobe. |
#23
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Use a radioactive eyepiece!
On Feb 2, 4:03*pm, Quadibloc wrote:
On Jan 30, 8:46*pm, Quadibloc wrote: On Jan 30, 5:22*pm, RichA wrote: The Kodak Ektamate and Ektar lenses all use thorium glass. *Pretty harmless just sitting around but I wouldn't want to press my eye to one for any length of time. http://www.surplusshed.com/pages/item/l3759.html There once were some World War II lenses that used radioactive glass, but that is long gone. Any surplus from the days of digital Group III fax machines would not use lenses made from that kind of glass - because the glass isn't made any more. I see that some radioactive glass was used even in the 1960s, so I'm mistaken... http://www.bnphoto.org/bnphoto/LostS...adioactive.htm John Savard That's a very interesting link about radioactive glass. Of all the possible bad elements, it seems thorium exposure is among the least dangerous, especially when encapsulated within glass.. |
#24
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Use a radioactive eyepiece!
On Feb 2, 7:03*pm, Quadibloc wrote:
I see that some radioactive glass was used even in the 1960s, so I'm mistaken... John Savard I believe it was still available ( or t least listed in the Schott catalog) in the 70s. http://www.richardfisher.com |
#25
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Use a radioactive eyepiece!
On 30/01/2013 7:22 PM, RichA wrote:
The Kodak Ektamate and Ektar lenses all use thorium glass. Pretty harmless just sitting around but I wouldn't want to press my eye to one for any length of time. http://www.surplusshed.com/pages/item/l3759.html What was the purpose of having a glass made of thorium? What was the advantage? Yousuf Khan |
#26
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Use a radioactive eyepiece!
On Feb 3, 12:03*pm, Yousuf Khan wrote:
On 30/01/2013 7:22 PM, RichA wrote: The Kodak Ektamate and Ektar lenses all use thorium glass. *Pretty harmless just sitting around but I wouldn't want to press my eye to one for any length of time. http://www.surplusshed.com/pages/item/l3759.html What was the purpose of having a glass made of thorium? What was the advantage? * * * * Yousuf Khan The heavier or more dense the glass the better, not to mention offering a narrower bandpass that assisted the Kodak film to seem as though offering a more visually identical result, instead of being somewhat UV sensitive. Kodak film was already kinda IR tolerant by simply not being sensitive to that longer wave spectrum because, even deep reds (w/o special filters) didn't record all that well. |
#27
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Use a radioactive eyepiece!
On Sun, 03 Feb 2013 15:03:05 -0500, Yousuf Khan
wrote: On 30/01/2013 7:22 PM, RichA wrote: The Kodak Ektamate and Ektar lenses all use thorium glass. Pretty harmless just sitting around but I wouldn't want to press my eye to one for any length of time. http://www.surplusshed.com/pages/item/l3759.html What was the purpose of having a glass made of thorium? What was the advantage? "In designing optical lenses, it is often desirable to employ glass with a high index of refraction. The greater the index of refraction, the greater the bending of the light. Since this reduces the necessary curvature of the glass, the lens can be made thinner and lighter. Unfortunately, glass with a high refractive index can also have a high dispersion. By adding thorium to the glass, a high refractive index (over 1.6) can be achieved while maintaining a low dispersion." http://www.orau.org/ptp/collection/c...cameralens.htm |
#28
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Use a radioactive eyepiece!
On Feb 3, 6:52*pm, Mark Sieving wrote:
On Sun, 03 Feb 2013 15:03:05 -0500, Yousuf Khan wrote: On 30/01/2013 7:22 PM, RichA wrote: The Kodak Ektamate and Ektar lenses all use thorium glass. *Pretty harmless just sitting around but I wouldn't want to press my eye to one for any length of time. http://www.surplusshed.com/pages/item/l3759.html What was the purpose of having a glass made of thorium? What was the advantage? "In designing optical lenses, it is often desirable to employ glass with a high index of refraction. The greater the index of refraction, the greater the bending of the light. Since this reduces the necessary curvature of the glass, the lens can be made thinner and lighter. Unfortunately, glass with a high refractive index can also have a high dispersion. *By adding thorium to the glass, a high refractive index (over 1.6) can be achieved while maintaining a low dispersion." http://www.orau.org/ptp/collection/c...cameralens.htm Plus thorium tends to cut-off a certain amount of UV. |
#29
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Use a radioactive eyepiece!
On Feb 1, 1:30*pm, Brad Guth wrote:
Thorium doesn't create weapons grade secondaries, so the Pentagon, DoD and oligarchs invested in those are always 100% opposed to any use of thorium that's also failsafe as well as the all-inclusive (birth to grave) cost of its clean and/or environmentally friendly energy to the end-use customers would not have to cost at most 10% of what we're currently paying. To get energy out of Thorium, you have to bombard it with neutrons to make it into fissionable Uranium-233. It may be harder to make a bomb out of that than from Uranium-235 or Plutonium-239, and so Thorium reactors wouldn't be subsidized by strategic defense, but I see no reason to imagine a conspiracy. The Pentagon and the Department of Defense are good things, because they protect Americans from ending up like the poor people in North Korea. John Savard |
#30
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Use a radioactive eyepiece!
On Feb 7, 7:58*am, Quadibloc wrote:
On Feb 1, 1:30*pm, Brad Guth wrote: Thorium doesn't create weapons grade secondaries, so the Pentagon, DoD and oligarchs invested in those are always 100% opposed to any use of thorium that's also failsafe as well as the all-inclusive (birth to grave) cost of its clean and/or environmentally friendly energy to the end-use customers would not have to cost at most 10% of what we're currently paying. To get energy out of Thorium, you have to bombard it with neutrons to make it into fissionable Uranium-233. It may be harder to make a bomb out of that than from Uranium-235 or Plutonium-239, and so Thorium reactors wouldn't be subsidized by strategic defense, but I see no reason to imagine a conspiracy. The Pentagon and the Department of Defense are good things, because they protect Americans from ending up like the poor people in North Korea. John Savard Spoken like a true global inflation redneck oligarch that’s public funded and set for life. When was the last time our government agencies didn’t obfuscate or lie to us? When was the last time our government didn’t help start or sustain a proxy war? Thorium only needs to be started with a neutron kicker that can be safely secured or turned off once that Th232 takes off on its own, whereas from that point on Th232 takes care of itself as long as there’s a sufficient volume of hot Th232 to work with. That’s also called a failsafe reactor. |
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