Re: [math-fun] Iridium & Indium (inside future analogue of light bulbs?)
The good news is that "quantum dots" don't depend upon normal valence electron energy levels in order to achieve their properties. Their properties are primarily a result of their size & configuration, which is in the 5-20 nm range -- almost achievable in the next 1-2 generations of lithography. So many of the needs for exotic materials with very specific bandgaps will be replaced by these engineered quantum dots. --- It was my impression that most, if not all, iridium comes from outer space; there is very little indigenous iridium on the Earth's surface. There may be a lot in the Earth's core, but it's going to be a little difficult to mine it from there. At 04:42 PM 12/4/2012, Warren Smith wrote:
Iridium is 40x rarer than gold and total world production is only about 10 tons annually.
Indium is also pretty rare, but not as rare: 1000 ton annual production. So I think if iridium is a substantial component of solid plastic lighting source then that will not be a useful technology for Average Joe Consumer. I would think you'd want ingredients common enough for million-ton production. If they can remove the need for Iridium and other rare elements, the general concept sounds excellent as a future lighting source.
-- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)
There's a layer of iridium due to the impact that wiped out the dinosaurs. http://en.wikipedia.org/wiki/Alvarez_hypothesis#Evidence On Tue, Dec 4, 2012 at 8:01 PM, Henry Baker <hbaker1@pipeline.com> wrote:
The good news is that "quantum dots" don't depend upon normal valence electron energy levels in order to achieve their properties.
Their properties are primarily a result of their size & configuration, which is in the 5-20 nm range -- almost achievable in the next 1-2 generations of lithography.
So many of the needs for exotic materials with very specific bandgaps will be replaced by these engineered quantum dots. --- It was my impression that most, if not all, iridium comes from outer space; there is very little indigenous iridium on the Earth's surface. There may be a lot in the Earth's core, but it's going to be a little difficult to mine it from there.
At 04:42 PM 12/4/2012, Warren Smith wrote:
Iridium is 40x rarer than gold and total world production is only about 10 tons annually.
Indium is also pretty rare, but not as rare: 1000 ton annual production. So I think if iridium is a substantial component of solid plastic lighting source then that will not be a useful technology for Average Joe Consumer. I would think you'd want ingredients common enough for million-ton production. If they can remove the need for Iridium and other rare elements, the general concept sounds excellent as a future lighting source.
-- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)
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-- Mike Stay - metaweta@gmail.com http://www.cs.auckland.ac.nz/~mike http://reperiendi.wordpress.com
Henry Baker:
It was my impression that most, if not all, iridium comes from outer space; there is very little indigenous iridium on the Earth's surface. There may be a lot in the Earth's core, but it's going to be a little difficult to mine it from there.
Volcanos are an adequate mechanism for having increased levels of iridium on the Earth's surface. There is sufficient iridium here that at least one recent paper argued that elevated concentrations of iridium in some desert wetlands "arise from processes common to wetland systems, and not a catastrophic extraterrestrial impact event". The argument was meant to counter a Younger Dryas impact hypothesis and thus may not adequately address the origin of the underlying, unconcentrated iridium.
The on-again, off-again Younger Dryas impact hypothesis is on again: http://www.pnas.org/content/early/2013/05/17/1301760110 On Dec 5, 2012, I wrote:
Henry Baker:
It was my impression that most, if not all, iridium comes from outer space; there is very little indigenous iridium on the Earth's surface. There may be a lot in the Earth's core, but it's going to be a little difficult to mine it from there.
Volcanos are an adequate mechanism for having increased levels of iridium on the Earth's surface. There is sufficient iridium here that at least one recent paper argued that elevated concentrations of iridium in some desert wetlands "arise from processes common to wetland systems, and not a catastrophic extraterrestrial impact event". The argument was meant to counter a Younger Dryas impact hypothesis and thus may not adequately address the origin of the underlying, unconcentrated iridium.
Zhang's recent paper asserts that there is some integer below 70 million such that infinitely many pairs of primes differ by that integer. Does anyone know if this theorem is generally accepted, (or can we assume that its publication in the Annals is sufficient evidence that it's correct) ? And, was it previously unknown that there exists any integer N such that infinitely many pairs of primes differ by N ? Thanks, Dan
All the chatter so far has been positive, but the preprint still has yet to be released. If correct this would be the first unconditional proof that such an N exists. Goldston-Pintz-Yildirim showed N <= 16 on Elliott-Halberstam. Charles Greathouse Analyst/Programmer Case Western Reserve University On Tue, May 21, 2013 at 2:53 PM, Dan Asimov <dasimov@earthlink.net> wrote:
Zhang's recent paper asserts that there is some integer below 70 million such that infinitely many pairs of primes differ by that integer.
Does anyone know if this theorem is generally accepted, (or can we assume that its publication in the Annals is sufficient evidence that it's correct) ?
And, was it previously unknown that there exists any integer N such that infinitely many pairs of primes differ by N ?
Thanks,
Dan
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I haven't seen this use of "on" before; a new bit of mathematical jargon for me. It took me a Wikipedia reference to figure out that "on Elliott-Halberstam" meant "on the condition that the Elliott-Halberstam Conjecture is true". On Tue, May 21, 2013 at 3:18 PM, Charles Greathouse < charles.greathouse@case.edu> wrote:
All the chatter so far has been positive, but the preprint still has yet to be released.
If correct this would be the first unconditional proof that such an N exists. Goldston-Pintz-Yildirim showed N <= 16 on Elliott-Halberstam.
Charles Greathouse Analyst/Programmer Case Western Reserve University
On Tue, May 21, 2013 at 2:53 PM, Dan Asimov <dasimov@earthlink.net> wrote:
Zhang's recent paper asserts that there is some integer below 70 million such that infinitely many pairs of primes differ by that integer.
Does anyone know if this theorem is generally accepted, (or can we assume that its publication in the Annals is sufficient evidence that it's correct) ?
And, was it previously unknown that there exists any integer N such that infinitely many pairs of primes differ by N ?
Thanks,
Dan
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Thanks, Charles and Allan! --Dan On 2013-05-21, at 12:46 PM, Allan Wechsler wrote:
I haven't seen this use of "on" before; a new bit of mathematical jargon for me. It took me a Wikipedia reference to figure out that "on Elliott-Halberstam" meant "on the condition that the Elliott-Halberstam Conjecture is true".
On Tue, May 21, 2013 at 3:18 PM, Charles Greathouse < charles.greathouse@case.edu> wrote:
All the chatter so far has been positive, but the preprint still has yet to be released.
If correct this would be the first unconditional proof that such an N exists. Goldston-Pintz-Yildirim showed N <= 16 on Elliott-Halberstam.
Charles Greathouse Analyst/Programmer Case Western Reserve University
On Tue, May 21, 2013 at 2:53 PM, Dan Asimov <dasimov@earthlink.net> wrote:
Zhang's recent paper asserts that there is some integer below 70 million such that infinitely many pairs of primes differ by that integer.
Does anyone know if this theorem is generally accepted, (or can we assume that its publication in the Annals is sufficient evidence that it's correct) ?
And, was it previously unknown that there exists any integer N such that infinitely many pairs of primes differ by N ?
Thanks,
Dan
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The preprint is now available to those with access, at < http://annals.math.princeton.edu/wp-content/uploads/YitangZhang.pdf >. --Dan On 2013-05-21, at 12:18 PM, Charles Greathouse wrote:
All the chatter so far has been positive, but the preprint still has yet to be released.
If correct this would be the first unconditional proof that such an N exists. Goldston-Pintz-Yildirim showed N <= 16 on Elliott-Halberstam.
Charles Greathouse Analyst/Programmer Case Western Reserve University
On Tue, May 21, 2013 at 2:53 PM, Dan Asimov <dasimov@earthlink.net> wrote:
Zhang's recent paper asserts that there is some integer below 70 million such that infinitely many pairs of primes differ by that integer.
Does anyone know if this theorem is generally accepted, (or can we assume that its publication in the Annals is sufficient evidence that it's correct) ?
And, was it previously unknown that there exists any integer N such that infinitely many pairs of primes differ by N ?
Thanks,
Dan
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thanks, dan i don't have access. could somebody, who feels comfortable doing so, email me a copy? thanks, bob baillie rjbaillie@frii.com --- Dan Asimov wrote:
The preprint is now available to those with access, at < http://annals.math.princeton.edu/wp-content/uploads/YitangZhang.pdf >.
--Dan
On 2013-05-21, at 12:18 PM, Charles Greathouse wrote:
All the chatter so far has been positive, but the preprint still has yet to be released.
If correct this would be the first unconditional proof that such an N exists. Goldston-Pintz-Yildirim showed N <= 16 on Elliott-Halberstam.
Charles Greathouse Analyst/Programmer Case Western Reserve University
On Tue, May 21, 2013 at 2:53 PM, Dan Asimov <dasimov@earthlink.net> wrote:
Zhang's recent paper asserts that there is some integer below 70 million such that infinitely many pairs of primes differ by that integer.
Does anyone know if this theorem is generally accepted, (or can we assume that its publication in the Annals is sufficient evidence that it's correct) ?
And, was it previously unknown that there exists any integer N such that infinitely many pairs of primes differ by N ?
Thanks,
Dan
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28 authors --- is this the perfect number? WFL On 5/21/13, Hans Havermann <gladhobo@teksavvy.com> wrote:
The on-again, off-again Younger Dryas impact hypothesis is on again:
http://www.pnas.org/content/early/2013/05/17/1301760110
On Dec 5, 2012, I wrote:
Henry Baker:
It was my impression that most, if not all, iridium comes from outer space; there is very little indigenous iridium on the Earth's surface. There may be a lot in the Earth's core, but it's going to be a little difficult to mine it from there.
Volcanos are an adequate mechanism for having increased levels of iridium on the Earth's surface. There is sufficient iridium here that at least one recent paper argued that elevated concentrations of iridium in some desert wetlands "arise from processes common to wetland systems, and not a catastrophic extraterrestrial impact event". The argument was meant to counter a Younger Dryas impact hypothesis and thus may not adequately address the origin of the underlying, unconcentrated iridium.
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In Physics, it would be 496. -----Original Message----- From: math-fun-bounces@mailman.xmission.com [mailto:math-fun-bounces@mailman.xmission.com] On Behalf Of Fred lunnon Sent: Tuesday, May 21, 2013 4:03 PM To: math-fun Subject: [EXTERNAL] Re: [math-fun] Younger Dryas Impact Hypothesis 28 authors --- is this the perfect number? WFL On 5/21/13, Hans Havermann <gladhobo@teksavvy.com> wrote:
The on-again, off-again Younger Dryas impact hypothesis is on again:
http://www.pnas.org/content/early/2013/05/17/1301760110
On Dec 5, 2012, I wrote:
Henry Baker:
It was my impression that most, if not all, iridium comes from outer space; there is very little indigenous iridium on the Earth's surface. There may be a lot in the Earth's core, but it's going to be a little difficult to mine it from there.
Volcanos are an adequate mechanism for having increased levels of iridium on the Earth's surface. There is sufficient iridium here that at least one recent paper argued that elevated concentrations of iridium in some desert wetlands "arise from processes common to wetland systems, and not a catastrophic extraterrestrial impact event". The argument was meant to counter a Younger Dryas impact hypothesis and thus may not adequately address the origin of the underlying, unconcentrated iridium.
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I think "The Effect of Peanut Butter on the Rotation of the Earth" may have had >496 authors. --Rich ---- Quoting Fred lunnon <fred.lunnon@gmail.com>:
28 authors --- is this the perfect number? WFL
On 5/21/13, Hans Havermann <gladhobo@teksavvy.com> wrote:
The on-again, off-again Younger Dryas impact hypothesis is on again:
http://www.pnas.org/content/early/2013/05/17/1301760110
On Dec 5, 2012, I wrote:
Henry Baker:
It was my impression that most, if not all, iridium comes from outer space; there is very little indigenous iridium on the Earth's surface. There may be a lot in the Earth's core, but it's going to be a little difficult to mine it from there.
Volcanos are an adequate mechanism for having increased levels of iridium on the Earth's surface. There is sufficient iridium here that at least one recent paper argued that elevated concentrations of iridium in some desert wetlands "arise from processes common to wetland systems, and not a catastrophic extraterrestrial impact event". The argument was meant to counter a Younger Dryas impact hypothesis and thus may not adequately address the origin of the underlying, unconcentrated iridium.
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8128 ? (Presumably the text didn't take up much room anyway.) WFL On 5/26/13, rcs@xmission.com <rcs@xmission.com> wrote:
I think "The Effect of Peanut Butter on the Rotation of the Earth" may have had >496 authors. --Rich
---- Quoting Fred lunnon <fred.lunnon@gmail.com>:
28 authors --- is this the perfect number? WFL
On 5/21/13, Hans Havermann <gladhobo@teksavvy.com> wrote:
The on-again, off-again Younger Dryas impact hypothesis is on again:
http://www.pnas.org/content/early/2013/05/17/1301760110
On Dec 5, 2012, I wrote:
Henry Baker:
It was my impression that most, if not all, iridium comes from outer space; there is very little indigenous iridium on the Earth's surface. There may be a lot in the Earth's core, but it's going to be a little difficult to mine it from there.
Volcanos are an adequate mechanism for having increased levels of iridium on the Earth's surface. There is sufficient iridium here that at least one recent paper argued that elevated concentrations of iridium in some desert wetlands "arise from processes common to wetland systems, and not a catastrophic extraterrestrial impact event". The argument was meant to counter a Younger Dryas impact hypothesis and thus may not adequately address the origin of the underlying, unconcentrated iridium.
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I don't know. Many of the so-called authors' names are clearly fictional (Orenthal J. Simpson, Ph.D. ?). Maybe all of them. --Dan On 2013-05-26, at 12:58 PM, rcs@xmission.com wrote:
I think "The Effect of Peanut Butter on the Rotation of the Earth" may have had >496 authors. --Rich
Has it only been a year? The hypothesis is off, again: http://www.nature.com/news/prehistoric-impact-idea-smacked-down-1.15194 On 21 May 2013 I wrote:
The on-again, off-again Younger Dryas impact hypothesis is on again: http://www.pnas.org/content/early/2013/05/17/1301760110
participants (10)
-
Allan Wechsler -
Charles Greathouse -
Dan Asimov -
Fred lunnon -
Hans Havermann -
Henry Baker -
Mike Stay -
rcs＠xmission.com -
Robert Baillie -
Schroeppel, Richard