Frenemies of TalkRational:
Nontheist Nexus |  Rants'n'Raves |  Secular Cafe |  Council of Ex-Muslims |  The Skeptical Zone |  rationalia |  Rational Skepticism |  Atheists Today | 
TalkRational  

FAQ Rules Staff List Calendar RSS
Go Back   TalkRational > Discussion > Life Science Discussions

Life Science Discussions Biology, Natural History, etc.

Closed Thread
 
Thread Tools Display Modes
Old 05-28-2010, 12:29 AM   #946224  /  #101
Mike PSS
Senior Member
 
Join Date: Mar 2008
Location: Florida
Posts: 8,628
Mike PSS
Default

Quote:
Originally Posted by Mike PSS View Post
From a model interpretation aspect, this is another egregious error in Humphreys analysis. If he used a single domain (fixed diffusion) then how can his model predict the 'knee' in the data? There is no factor in his model to account for multi-diffusion effects.

He should have linearized his data, which supports my point 1) above that seems to show that Humphreys recreated the low-temperature curve in his creationist model somehow.
Dave,
Quit whinging about not being able to provide links and respond to my point above.

The more that Humphreys paper is investigated the worse it becomes. How can you have a "knee" in your model if your using a single-domain (i.e. single diffusion coefficient)? Please reply, it's a pretty simple question.
Mike PSS is offline   topbottom
Old 05-28-2010, 04:28 AM   #946423  /  #102
Dave Hawkins
Senior Member
 
Dave Hawkins's Avatar
 
Join Date: Mar 2008
Location: Kansas City, MO Area
Posts: 15,715
Dave Hawkins
Default

Quote:
Originally Posted by Mike PSS View Post
Quote:
Originally Posted by Mike PSS View Post
From a model interpretation aspect, this is another egregious error in Humphreys analysis. If he used a single domain (fixed diffusion) then how can his model predict the 'knee' in the data? There is no factor in his model to account for multi-diffusion effects.

He should have linearized his data, which supports my point 1) above that seems to show that Humphreys recreated the low-temperature curve in his creationist model somehow.
Dave,
Quit whinging about not being able to provide links and respond to my point above.

The more that Humphreys paper is investigated the worse it becomes. How can you have a "knee" in your model if your using a single-domain (i.e. single diffusion coefficient)? Please reply, it's a pretty simple question.
I don't think "single domain" = "single diffusion coefficient" ... I think the diffusion coefficient changes with temperature. It's just that it changes at a faster rate with temperature above the knee.
__________________
“The modern literature is full of funny ideas about the state of the natural sciences in antiquity. Those funny ideas can only come up if somebody does not study very carefully ... " --Dieter Lelgemann, Researcher at the Institute for Geodesy and Geoinformatics, Technical University of Berlin.
Dave Hawkins is offline   topbottom
Old 05-28-2010, 04:36 AM   #946429  /  #103
osmanthus
Bent member
 
osmanthus's Avatar
 
Join Date: Jun 2008
Location: Australia
Posts: 3,356
osmanthus
Default

And exactly why do you think that, Dave? What evidence leads you to that conclusion?
__________________
I always knew I'd find the source of all evil in a vegan bakery.
osmanthus is offline   topbottom
Old 05-28-2010, 04:37 AM   #946431  /  #104
TestyCalibrate
Someone oughta fix the door
dummy
 
TestyCalibrate's Avatar
 
Join Date: Sep 2008
Location: I've mistaken blueberries for blueberries!
Posts: 20,004
TestyCalibrate
Default

Quote:
Originally Posted by Dave Hawkins View Post
Quote:
Originally Posted by Mike PSS View Post
Quote:
Originally Posted by Mike PSS View Post
From a model interpretation aspect, this is another egregious error in Humphreys analysis. If he used a single domain (fixed diffusion) then how can his model predict the 'knee' in the data? There is no factor in his model to account for multi-diffusion effects.

He should have linearized his data, which supports my point 1) above that seems to show that Humphreys recreated the low-temperature curve in his creationist model somehow.
Dave,
Quit whinging about not being able to provide links and respond to my point above.

The more that Humphreys paper is investigated the worse it becomes. How can you have a "knee" in your model if your using a single-domain (i.e. single diffusion coefficient)? Please reply, it's a pretty simple question.
I don't think "single domain" = "single diffusion coefficient" ... I think the diffusion coefficient changes with temperature. It's just that it changes at a faster rate with temperature above the knee.
Dave, serious question: Do you know how the diffusion coefficient is derived?
__________________
Cabin fever.
TestyCalibrate is offline   topbottom
Old 05-28-2010, 05:54 AM   #946484  /  #105
Loechelt
Senior Member
 
Loechelt's Avatar
 
Join Date: May 2010
Location: Tempe, Arizona
Posts: 674
Loechelt
Default

Quote:
Originally Posted by Tension View Post
Ok sorry to ask another strupid question but i was just re reading this thread and I noticed on the first page Dr Loechelt posted this graph , I this graph from Humphreys experiment or is it Dr Loechelts corrected one, basically im asking is it right ot wrong coz I dont understand it. I know I seem like an idiot and im sorry its just hard for me to understand this stuff.
The measured data and fitting curve are from Humphreys' diffusion experiment. The other two lines were calculated from equations that I pulled from the literature.
Loechelt is offline   topbottom
Old 05-28-2010, 05:59 AM   #946487  /  #106
Loechelt
Senior Member
 
Loechelt's Avatar
 
Join Date: May 2010
Location: Tempe, Arizona
Posts: 674
Loechelt
Default

Quote:
Originally Posted by Steviepinhead View Post
I'm gonna hazard a guess that this graph is Dr. Loechelt's comparison of the data from the various papers cited in the top right corner of the graph. I'm sure that the graph has been sourced any number of times by now, but the thread -- together with it's predecessor -- has gotten to be a long one, with a variety of different graphs assuming center stage at various times, and at times more than once...

But I could easily be wrong, and am interested in knowing the right answer as well.
Stevie,

You are right about the interpretation of the data. Regarding the source of the graph, it is original. Since I wrote the computer program, I can spit this kind of stuff out pretty fast. So you might see a lot of similar graphs with minor variations.
Loechelt is offline   topbottom
Old 05-28-2010, 06:02 AM   #946488  /  #107
Loechelt
Senior Member
 
Loechelt's Avatar
 
Join Date: May 2010
Location: Tempe, Arizona
Posts: 674
Loechelt
Default

Quote:
Originally Posted by Tension View Post
CRAP! I just realised thats the wrong graph! I meant to ask about this graph!
Tension,

The measured data are my corrected version of the helium retention data published by Gentry, which Humphreys used. All of the other points are calculated by my diffusion model using different sources for the helium diffusion parameters.
Loechelt is offline   topbottom
Old 05-28-2010, 06:10 AM   #946494  /  #108
Loechelt
Senior Member
 
Loechelt's Avatar
 
Join Date: May 2010
Location: Tempe, Arizona
Posts: 674
Loechelt
Default

Quote:
Originally Posted by Jet Black View Post
Quote:
Originally Posted by Tension View Post
Ok sorry to ask another strupid question but i was just re reading this thread and I noticed on the first page Dr Loechelt posted this graph , I this graph from Humphreys experiment or is it Dr Loechelts corrected one, basically im asking is it right ot wrong coz I dont understand it. I know I seem like an idiot and im sorry its just hard for me to understand this stuff.
asking questions about things you don't understand is the very opposite of being an idiot the cleverest people in the world do that all the time.
Speaking of asking questions about things you do not understand.

1. How do you get a user profile picture to appear in a post? I editted my profile using the user control panel. The picture uploaded fine and is visible in my profile page, but it still does not display when I post a message. The size is 90x100, 28 kB.

2. How do you upload a full size graphics into a post? I tried uploading an attachment which worked fine. However, the image appeared as a thumbnail. I would prefer to have it visible the same way you include a graphics image. I can do that if I have a URL. But if it is an image uploaded from my computer, it only displays a thumbnail.

Thanks!
Loechelt is offline   topbottom
Old 05-28-2010, 06:17 AM   #946499  /  #109
Loechelt
Senior Member
 
Loechelt's Avatar
 
Join Date: May 2010
Location: Tempe, Arizona
Posts: 674
Loechelt
Default

Quote:
Originally Posted by Dave Hawkins View Post
Quote:
Originally Posted by Dave Hawkins View Post
OK ... Dr. Loechelt ... please explain something to me ... Dr. Humphreys says you overlooked part of one of your own quotes. Which part of which quote does he think you overlooked and what is he talking about and what is your response to his criticism? Put it in laymanspeak please. I'm a busy, distracted guy who only vaguely remembers material science class and calculus class. My engineering degree is 25 years old and I never used it for anything except to get into Air Force flight school. :-)
OK guys, really ... how tough can this be to figure out what I'm talking about here? All you have to do is look at the previous post (sorry, I said earlier it was two posts up). But here's a link ... http://talkrational.org/showthread.p...198#post944198 ... it obviously would be more appropriate to ask Humphreys these questions, but he's not here and you are. So ... can you answer them?
Dave,

The hard part was not following the thread back to your earlier post. The thing I have trouble following is understanding which quote I supposedly overlooked when Humphreys neither gives the text nor reference of the author he is referring to. I do not have time to reverse engineer one of Humphreys' vague statements. Like I said, I have put in more than my fair share of time and effort on my end of this debate. If something is unclear on Humphreys end, it is his job to clarify it. Thanks for understanding.
Loechelt is offline   topbottom
Old 05-28-2010, 06:28 AM   #946504  /  #110
Loechelt
Senior Member
 
Loechelt's Avatar
 
Join Date: May 2010
Location: Tempe, Arizona
Posts: 674
Loechelt
Default

Quote:
Originally Posted by Dave Hawkins View Post
Dr. Loechelt ...
Quote:
He totally ignored the temperature dependence of the majority of "tightly-bound" helium that was liberated at high temperatures. Herein lies the fatal error.
How do you figure that he totally ignored this? My understanding of this "low temperature tail" is that it's the "defect portion" of the curve. I see no evidence that Humphreys ignored this. In fact, he discussed it at length and even extrapolated it to calculate what temperature would be required for the Old Earth model to work. Very cold BTW ... sub-zero.
Dave,

I am not sure if we are talking about the same thing here. My statement was that Humphreys ignored the high-temperature or "intrinsic" portion of the curve. I base that statement on the observation that after carefully studying his writings, I cannot see how it entered into the analysis. Your statement is that Humphreys used the low-temperature or "defect" portion of the curve and discussed it at length. That is correct. So you seem to agree with me. I said he ignored the high-temperature portion of the curve. You said he discussed and used the low-temperature portion of the curve. Where is the disagreement? I don't follow you here.
Loechelt is offline   topbottom
Old 05-28-2010, 06:42 AM   #946515  /  #111
Loechelt
Senior Member
 
Loechelt's Avatar
 
Join Date: May 2010
Location: Tempe, Arizona
Posts: 674
Loechelt
Default

Quote:
Originally Posted by JonF View Post
Quote:
Originally Posted by Mike PSS View Post
In Humphreys paper, Young Helium Diffusion Age of Zircons Supports Accelerated Nuclear Decay, Figure 16 on Page 62 (.pdf page 38) he shows a comparison graph of what different temperatures to the "uniformitarian" model would happen.
Quote:
Figure 16. Different temperatures cannot rescue the uniformitarian model. Errors for data and models are the same as in Figure 15. Dotted line is best fit to last four points. Dashed lines are 1σ upper and lower bounds to fit.
I can't find an image to post and the .pdf is locked for image capture so you'll have to go to the link.
Tain't locked for screen grab.

Here is the image with the extrapolation done from the high-temperature portion of the curve. It points to the "present temperatures" data.

Click image for larger version

Name:	Humphreys-16 Arrow.png
Views:	99
Size:	306.3 KB
ID:	2029
Loechelt is offline   topbottom
Old 05-28-2010, 06:46 AM   #946518  /  #112
TestyCalibrate
Someone oughta fix the door
dummy
 
TestyCalibrate's Avatar
 
Join Date: Sep 2008
Location: I've mistaken blueberries for blueberries!
Posts: 20,004
TestyCalibrate
Default

which data points are we looking at?
__________________
Cabin fever.
TestyCalibrate is offline   topbottom
Old 05-28-2010, 06:57 AM   #946520  /  #113
Loechelt
Senior Member
 
Loechelt's Avatar
 
Join Date: May 2010
Location: Tempe, Arizona
Posts: 674
Loechelt
Default

Quote:
Originally Posted by JonF View Post
Quote:
Originally Posted by Dave Hawkins View Post
OK ... Dr. Loechelt ... please explain something to me ... Dr. Humphreys says you overlooked part of one of your own quotes. Which part of which quote does he think you overlooked and what is he talking about and what is your response to his criticism? Put it in laymanspeak please. I'm a busy, distracted guy who only vaguely remembers material science class and calculus class. My engineering degree is 25 years old and I never used it for anything except to get into Air Force flight school. :-)
My second posting of my response is here. Dr. Loechelt has responded at A Response to the RATE Team Regarding Helium Diffusion in Zircon. The only one of your quesions he hasn't addressed is which quote he thinks Humphrey's is referring to, but I think that's pretty obvious. It's:

Quote:
Originally Posted by Loechelt
Quote:
Originally Posted by Reiners
Zircons with a wide range of ages and radiation dosages exhibited approximately the same degree of non-Arrhenius behavior in initial diffusion steps. Although such modeling does not prove such a mechanism for these non-Arrhenius effects, it suggests that only a small proportion of gas resides in domains that exhibit anomalously high diffusivity, and therefore this phenomenon may not significantly affect the bulk closure temperature or He diffusion properties of most natural zircons.
If you have any further questions, please compose them as responses to Dr. Loechelt's or my already-posted response. Don't pretend that you haven't been answered many times over. Do your homework, Davie-dipples.
JonF,

If that is indeed the quote that Humphreys is referring to, then I would argue that he is the one who is misquoting Reiners. Here is the text of Humphreys' original comment.

Quote:
Loechelt is right in claim (A), but wrong in claim (B). He overlooked part of one of his own quotes, in which an expert pointed out that loose helium would only affect the initial steps of the laboratory measurement, because after the initial steps the loose helium would be gone.
I emphasize the parts of Humphreys' statement that I take issue with.

First, the use of the word only implies exclusivity. Reiners never makes an exclusive statement. He only mentions the behavior he observed in the inital heating ramp. There is nothing in his statement or experiment to preclude the possibility of helium remaining after the initial ramp. It was just a topic that was outside of the scope of this particular study.

Second, the statement about the loose helium being gone after the initial ramp are not in the quote by Reiners! Humphreys is injecting his own ideas into the words of others. You can draw your own conclusions.
Loechelt is offline   topbottom
Old 05-28-2010, 07:47 AM   #946530  /  #114
Crazalus
Senior Member
 
Join Date: Jan 2009
Posts: 3,222
Crazalus
Default

Quote:
Originally Posted by Loechelt View Post
Quote:
Originally Posted by Jet Black View Post
Quote:
Originally Posted by Tension View Post
Ok sorry to ask another strupid question but i was just re reading this thread and I noticed on the first page Dr Loechelt posted this graph , I this graph from Humphreys experiment or is it Dr Loechelts corrected one, basically im asking is it right ot wrong coz I dont understand it. I know I seem like an idiot and im sorry its just hard for me to understand this stuff.
asking questions about things you don't understand is the very opposite of being an idiot the cleverest people in the world do that all the time.
Speaking of asking questions about things you do not understand.

1. How do you get a user profile picture to appear in a post? I editted my profile using the user control panel. The picture uploaded fine and is visible in my profile page, but it still does not display when I post a message. The size is 90x100, 28 kB.
That would be the Avatar you want to change... 100x100, or 19.5kb.
Quote:
2. How do you upload a full size graphics into a post? I tried uploading an attachment which worked fine. However, the image appeared as a thumbnail. I would prefer to have it visible the same way you include a graphics image. I can do that if I have a URL. But if it is an image uploaded from my computer, it only displays a thumbnail.
Find an image hosting site... I use Photobucket myself, but Imageshack works well enough. (Photobucket needs you to have an account with them. It's free and you get an album so you can just grab the link from it, rather than having to re-upload it each time. Imageshack you don't need the account, but it's good for a one-time thing.)


http://imageshack.us/

http://photobucket.com/
Crazalus is offline   topbottom
Old 05-28-2010, 07:51 AM   #946532  /  #115
Crazalus
Senior Member
 
Join Date: Jan 2009
Posts: 3,222
Crazalus
Default

Quote:
Originally Posted by Loechelt View Post
Second, the statement about the loose helium being gone after the initial ramp are not in the quote by Reiners! Humphreys is injecting his own ideas into the words of others. You can draw your own conclusions.
Misquoting someone is bad enough, but accusing someone of ignoring part of a quote when the part they've "ignored" is the bit you've added to the quote is just.... well, it's just dishonest.


Poor Dave... will he admit that his "hero" got it wrong? (hell no... he hasn't yet, so why expect him to start now?)
Crazalus is offline   topbottom
Old 05-28-2010, 02:24 PM   #946750  /  #116
JonF
Accoster of Tard
 
Join Date: Mar 2008
Posts: 2,181
JonF
Default

Quote:
Originally Posted by Jet Black View Post
Quote:
Originally Posted by JonF View Post
Quote:
Originally Posted by Jet Black View Post
What is the physical justification for this? Pretend you're doing your PhD viva.
Ain't gonnna pretend. The "tightly bound" helium is locked inside the crystal lattice, albeit in regions damaged by the crash of the alpha particle. The "loosely bound" helium is on or very near the edges of large defects or cracks that extend to the outer surface, or very near the outer surface. For reasonable sample shapes (here are some random zircons):



and reasonably undamaged samples, the vast majority of the helium will be in the former category.
ok. Just out of interest, for a given zircon, do you have any idea what the average number of helium atoms is per unit cell? The reason I ask is that one of my concerns regarding the YEC model is the buildup of wigner energy. They are suggesting fluxes of things like alpha particles that are so high, that I do actually wonder whether this could be a problem to them.
Not a clue. Nut i will certainly be a function of age.
JonF is online now   topbottom
Old 05-28-2010, 02:36 PM   #946762  /  #117
Jet Black
Finding Things Out
Mod: ASS, LSD, Phys Sci
 
Jet Black's Avatar
 
Join Date: Jan 1970
Posts: 29,311
Jet Black has disabled comments
Default

Quote:
Originally Posted by JonF View Post
Quote:
Originally Posted by Jet Black View Post
Quote:
Originally Posted by JonF View Post
Ain't gonnna pretend. The "tightly bound" helium is locked inside the crystal lattice, albeit in regions damaged by the crash of the alpha particle. The "loosely bound" helium is on or very near the edges of large defects or cracks that extend to the outer surface, or very near the outer surface. For reasonable sample shapes (here are some random zircons):



and reasonably undamaged samples, the vast majority of the helium will be in the former category.
ok. Just out of interest, for a given zircon, do you have any idea what the average number of helium atoms is per unit cell? The reason I ask is that one of my concerns regarding the YEC model is the buildup of wigner energy. They are suggesting fluxes of things like alpha particles that are so high, that I do actually wonder whether this could be a problem to them.
Not a clue. Nut i will certainly be a function of age.
oh of course, btu I am just thinking about the YEC model here. It calls for a vastly higher flux of things like alpha particles and neutrons than are experienced in nature. When radiation interacts with the lattice, atoms may be displaced into higher energy states, which can then decay back to their original lower energy state. The energy stored in these high energy states is known as wigner energy. This is particularly important in nuclear reactors involving solid moderators like graphite, since they can build up large amounts of wigner energy, which can be spontaneously released and cause massive heating and fires, as happened in windscale. For the standard model where the helium builds up over hundreds to thousands of years, this will not be a problem, since the wigner energy will equally dissipate over such timescales, however YECs are trying to dump all this energy in a year or less during the AND period and so wigner energy buildup would be far more rapid. If the average number of helium atoms per unit cell is high (approaching 4, I think - since there are 4 cages per unit cell), then this could pose substantial problems for YECs in this regard.
__________________
The Feynmann Algorithm: (1) Write down the problem (2) Think real hard (3) Write down the solution
Jet Black is offline   topbottom
Old 05-28-2010, 02:43 PM   #946771  /  #118
Mike PSS
Senior Member
 
Join Date: Mar 2008
Location: Florida
Posts: 8,628
Mike PSS
Default

JB,
In the YEC model, if Wignar Energy becomes a factor for A.N.D. during the flood year, will that Wignar Energy be liberated before or after the earth turns into a ball of plasma?
Mike PSS is offline   topbottom
Old 05-28-2010, 02:43 PM   #946772  /  #119
JonF
Accoster of Tard
 
Join Date: Mar 2008
Posts: 2,181
JonF
Default

Quote:
Originally Posted by VoxRat View Post
Quote:
Originally Posted by JonF View Post
...
Note that there's plenty of data taken at or below 300C after the first nine steps.

Right.
It seems to be Humphreys's assumption that, having gone through those initial steps, all the "loose helium" would have been boiled off, and the only thing left - no matter what temperature you looked at - would be the helium we're interested in.

I suspect that assumption is wrong... but what do I know?
No need to suspect. Loechelt analyzed how much "loosely bound" helium would remain throughout that very experiment, at :

Quote:
Originally Posted by Loechelt
1. The loosely bound helium in my model would have been exhausted during the initial heating ramp of the diffusion experiment, and cannot explain the high diffusivity that was observed at low temperatures later in the experiment.

Humphreys made this claim apparently without performing any calculations. In contrast, I had previously performed these calculations. In Appendix C of my technical paper (Loechelt, 2008c), I discussed how the kinetic parameters of my multidomain diffusion model were extracted by performing forward modeling of the stepwise heating diffusion experiment inside a nonlinear optimization loop. Although not shown in that paper, this extraction technique required the explicit calculation of the fraction of gas released during the diffusion experiment by both the high-retentivity and low-retentivity helium domains. The results of these calculations are shown in Fig. 1, using helium diffusion data from the 2004 RATE CRSQ paper (Humphreys et al., 2004).


As can be seen, 30% of the loosely-bound helium (orange triangles) survived the first heating ramp at 15 hours, and 15% even survived the second heating ramp at 30 hours. Therefore, enough loosely-bound helium remained to explain the low-temperature diffusivity through-out the entire experiment. Although the exact gas release values at any given time step are sensitive to the assumptions used in constructing the multidomain model, most notably the partitioning fraction between the two helium domains, it does demonstrate that it is possible for a fraction of the loosely-bound helium to remain throughout the entire experiment, contrary to Humphreys’ unsubstantiated claims.

Last edited by JonF; 05-28-2010 at 03:02 PM.
JonF is online now   topbottom
Old 05-28-2010, 02:57 PM   #946782  /  #120
JonF
Accoster of Tard
 
Join Date: Mar 2008
Posts: 2,181
JonF
Default

Quote:
Originally Posted by Dave Hawkins View Post
Quote:
Originally Posted by Mike PSS View Post
Quote:
Originally Posted by Mike PSS View Post
From a model interpretation aspect, this is another egregious error in Humphreys analysis. If he used a single domain (fixed diffusion) then how can his model predict the 'knee' in the data? There is no factor in his model to account for multi-diffusion effects.

He should have linearized his data, which supports my point 1) above that seems to show that Humphreys recreated the low-temperature curve in his creationist model somehow.
Dave,
Quit whinging about not being able to provide links and respond to my point above.

The more that Humphreys paper is investigated the worse it becomes. How can you have a "knee" in your model if your using a single-domain (i.e. single diffusion coefficient)? Please reply, it's a pretty simple question.
I don't think "single domain" = "single diffusion coefficient" ... I think the diffusion coefficient changes with temperature.
Yes.

Quote:
It's just that it changes at a faster rate with temperature above the knee.
100% one-hundred-eighty degrees wrong. Just like Humphreys got it wrong. Single-domain or multiple-domain, for the real world it changes at about the same rate below the knee ... in fact, in the real world there effectively is no knee. The pronounced knee seen in the low-temperature part of the RATE diffusion experiments is real in the lab because comparable amounts of "loosely bound" and "tightly bound" helium are being released. In the real world at real pressures, even at those relatively low temperatures, the knee is so slight as to be invisible because there is so little "loosely bound" helium to release that it's overwhelmed by the release of "tightly bound" helium. In this graph the blue line is an appropriate representation of how diffusion rate changes with temperature in the lab under vacuum and the red and yellow lines are appropriate representations of how difffusion rate changes with temperature in real-world conditions:



IOW, RATE's lab data is perfectly good, and you can either analyze the entirety of it with a two-domain model or just the high-temperature part with a single domain model. Either way leads to a diffusion rate at low temperature that is much slower than Humphreys' model and the lab results, and a difffusion rate at high temperature that is about the same as the lab results.
JonF is online now   topbottom
Old 05-28-2010, 03:02 PM   #946793  /  #121
JonF
Accoster of Tard
 
Join Date: Mar 2008
Posts: 2,181
JonF
Default

Quote:
Originally Posted by Loechelt View Post
Quote:
Originally Posted by JonF View Post
Quote:
Originally Posted by Dave Hawkins View Post
OK ... Dr. Loechelt ... please explain something to me ... Dr. Humphreys says you overlooked part of one of your own quotes. Which part of which quote does he think you overlooked and what is he talking about and what is your response to his criticism? Put it in laymanspeak please. I'm a busy, distracted guy who only vaguely remembers material science class and calculus class. My engineering degree is 25 years old and I never used it for anything except to get into Air Force flight school. :-)
My second posting of my response is here. Dr. Loechelt has responded at A Response to the RATE Team Regarding Helium Diffusion in Zircon. The only one of your quesions he hasn't addressed is which quote he thinks Humphrey's is referring to, but I think that's pretty obvious. It's:


If you have any further questions, please compose them as responses to Dr. Loechelt's or my already-posted response. Don't pretend that you haven't been answered many times over. Do your homework, Davie-dipples.
JonF,

If that is indeed the quote that Humphreys is referring to, then I would argue that he is the one who is misquoting Reiners. Here is the text of Humphreys' original comment.

Quote:
Loechelt is right in claim (A), but wrong in claim (B). He overlooked part of one of his own quotes, in which an expert pointed out that loose helium would only affect the initial steps of the laboratory measurement, because after the initial steps the loose helium would be gone.
I emphasize the parts of Humphreys' statement that I take issue with.

First, the use of the word only implies exclusivity. Reiners never makes an exclusive statement. He only mentions the behavior he observed in the inital heating ramp. There is nothing in his statement or experiment to preclude the possibility of helium remaining after the initial ramp. It was just a topic that was outside of the scope of this particular study.

Second, the statement about the loose helium being gone after the initial ramp are not in the quote by Reiners! Humphreys is injecting his own ideas into the words of others. You can draw your own conclusions.
I posted the context of Reiners' quote twice before. Here it is again:

Quote:
Originally Posted by Reiners
It is important to note that most available He diffusion experiments for zircon display anomalously high diffusivity in the earliest stages of step-heating. This behavior has also been observed in other minerals and is not well understood, and could have a range of origins, including effects from geometric vagaries of natural grain morphology, localized high-diffusivity from small high radiation-damage zones, crystallographically anisotropic diffusion, or inhomogeneously distributed He. Reiners et al. (2004) compared these non- Arrhenius features of the diffusion experiments with forward models of degassing from multiple domains of different sizes. These features could be matched well by positing small fractions of gas (2–4%) in domains with length-scales that are a factor of about 25–200 times smaller than the bulk grains themselves (Fig. 3). Zircons with a wide range of ages and radiation dosages exhibited approximately the same degree of non-Arrhenius behavior in initial diffusion steps. Although such modeling does not prove such a mechanism for these non-Arrhenius effects, it suggests that only a small proportion of gas resides in domains that exhibit anomalously high diffusivity, and therefore this phenomenon may not significantly affect the bulk closure temperature or He diffusion properties of most natural zircons.

Although Reiners et al. (2004) suggested that the anomalously high and non-Arrhenius diffusion seen in early stages of step heating experiments can be explained in ways that may not be important for most thermochronometric applications, this has yet to be proven. These and other features of He diffusion in zircon (and in other minerals) such as erratic behavior in some samples, are not easily explained and their origins may yet prove to be important in understanding anomalous ages and model thermal histories. One potential concern for step-heating diffusion studies of the type shown here, and which is common to most other He diffusion studies, is the possibility for crystallographic modifications during experiments themselves. If heating at experimental temperatures and durations changes crystallographic features that affect diffusivity (e.g., by causing annealing), it is conceivable that such stepheating experiments may underestimate He diffusivity in natural zircons. Other important unresolved questions include the role of localized radiation damage zones in crystals whose bulk compositions would not suggest signifi cant damage, the possibility of anisotropic diffusion, the interaction of microstructures, inclusions, or fission-tracks with migrating He, the possible role of pressure in He diffusion, and He solubility in zircon.
Whoopsie, hit Submit way too soon.

It seems that Humphreys is combining "small proportion of gas resides in domains that exhibit anomalously high diffusivity" and "that the anomalously high and non-Arrhenius diffusion " and drawing an unwarranted conclusion.

Last edited by JonF; 05-28-2010 at 03:07 PM.
JonF is online now   topbottom
Old 05-28-2010, 03:06 PM   #946799  /  #122
Jet Black
Finding Things Out
Mod: ASS, LSD, Phys Sci
 
Jet Black's Avatar
 
Join Date: Jan 1970
Posts: 29,311
Jet Black has disabled comments
Default

Quote:
Originally Posted by Mike PSS View Post
JB,
In the YEC model, if Wignar Energy becomes a factor for A.N.D. during the flood year, will that Wignar Energy be liberated before or after the earth turns into a ball of plasma?
I usually consider the earth turning into a ball of plasma as a perturbation to the state of the planet and thus irrelevant for the purposes of my analysis of their stupid ideas.
__________________
The Feynmann Algorithm: (1) Write down the problem (2) Think real hard (3) Write down the solution
Jet Black is offline   topbottom
Old 05-28-2010, 03:26 PM   #946853  /  #123
JonF
Accoster of Tard
 
Join Date: Mar 2008
Posts: 2,181
JonF
Default

Quote:
Originally Posted by Jet Black View Post
Quote:
Originally Posted by Mike PSS View Post
JB,
In the YEC model, if Wignar Energy becomes a factor for A.N.D. during the flood year, will that Wignar Energy be liberated before or after the earth turns into a ball of plasma?
I usually consider the earth turning into a ball of plasma as a perturbation to the state of the planet and thus irrelevant for the purposes of my analysis of their stupid ideas.
Consider a spherical cow ...
JonF is online now   topbottom
Old 05-28-2010, 03:26 PM   #946854  /  #124
VoxRat
Senior Member
 
VoxRat's Avatar
 
Join Date: Mar 2008
Posts: 40,799
VoxRat has disabled comments
Default

Quote:
Originally Posted by JonF View Post
...
No need to suspect. Loechelt analyzed how much "loosely bound" helium would remain throughout that very experiment, at

Quote:
Originally Posted by Loechelt
...
In Appendix C of my technical paper (Loechelt, 2008c), I discussed how the kinetic parameters of my multidomain diffusion model were extracted by performing forward modeling of the stepwise heating diffusion experiment inside a nonlinear optimization loop. Although not shown in that paper, this extraction technique required the explicit calculation of the fraction of gas released during the diffusion experiment by both the high-retentivity and low-retentivity helium domains. The results of these calculations are shown in Fig. 1, using helium diffusion data from the 2004 RATE CRSQ paper (Humphreys et al., 2004).


As can be seen, 30% of the loosely-bound helium (orange triangles) survived the first heating ramp at 15 hours, and 15% even survived the second heating ramp at 30 hours. Therefore, enough loosely-bound helium remained to explain the low-temperature diffusivity through-out the entire experiment. ....
The figure shows the results of some calculations (which, frankly, I'm not competent to check). What are the (theoretical, remember, since these are calculations, not observations) temperatures corresponding to the three plateaus?
VoxRat is offline   topbottom
Old 05-28-2010, 03:49 PM   #946893  /  #125
JonF
Accoster of Tard
 
Join Date: Mar 2008
Posts: 2,181
JonF
Default

Quote:
Originally Posted by VoxRat View Post
The figure shows the results of some calculations (which, frankly, I'm not competent to check). What are the (theoretical, remember, since these are calculations, not observations) temperatures corresponding to the three plateaus?
The temperatures are real and are listed the table and figure in this message. IOW, it's an analysis of the lab measurements Humphrey's published.

Last edited by VoxRat; 05-28-2010 at 03:53 PM. Reason: fixed quote tags - largely for the thrill of editing someone else's post.
JonF is online now   topbottom
Closed Thread

  TalkRational > Discussion > Life Science Discussions

Tags
"algebras, a cromulent discussion, could sanshou be the one?, dave the king of science, don't mention sanshou, how do they work?", wishful thinking, would sandshoe tea be fun

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT. The time now is 01:53 AM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ©2008 - 2014, TalkRational.org