"Snag"Â wrote in message news:tpfbt0$3ufpe$1@dont-email.me...
 A neighbor's friend brought a small welding repair over for me . It's
an I beam that is the backbone of a PTO powered post hole auger . But
that's not what this post is about , this post is about OHMYGAWD I love
my new welder . The flange that carries the yoke that the auger hangs on
had fatigued and split from the web , First order was to pull it back
into position and tack it in place . Then vee one side and run a bead
then flip and grind down to fresh weld and lay in a couple of passes -
all on the lowest power setting . Welding 1/4" thick reinforcing strips
on both sides had it all the way up to half power . I may never need to
use my tombstone welder again ...
Snag
------------------
Flux core?
"Snag"Â wrote in message news:tpfbt0$3ufpe$1@dont-email.me...
 A neighbor's friend brought a small welding repair over for me . It's
an I beam that is the backbone of a PTO powered post hole auger . But
that's not what this post is about , this post is about OHMYGAWD I love
my new welder . The flange that carries the yoke that the auger hangs on
had fatigued and split from the web , First order was to pull it back
into position and tack it in place . Then vee one side and run a bead
then flip and grind down to fresh weld and lay in a couple of passes -
all on the lowest power setting . Welding 1/4" thick reinforcing strips
on both sides had it all the way up to half power . I may never need to
use my tombstone welder again ...
Snag
------------------
Flux core?
On 1/8/2023 2:35 PM, Jim Wilkins wrote:I've got a lincoln AC/DC "tombstone" and it's plenty heavy enough for
"Snag" wrote in message news:tpfbt0$3ufpe$1@dont-email.me...
A neighbor's friend brought a small welding repair over for me . It's
an I beam that is the backbone of a PTO powered post hole auger . But
that's not what this post is about , this post is about OHMYGAWD I love
my new welder . The flange that carries the yoke that the auger hangs on
had fatigued and split from the web , First order was to pull it back
into position and tack it in place . Then vee one side and run a bead
then flip and grind down to fresh weld and lay in a couple of passes -
all on the lowest power setting . Welding 1/4" thick reinforcing strips
on both sides had it all the way up to half power . I may never need to
use my tombstone welder again ...
Snag
------------------
Flux core?
I've been debating selling mine. On the rare occasion when I really
might need to burn some 7018 for some thicker plate I have the AHP ACDC
Pulse TIG/Stick. I like running DC stick so much better than using the
AC cracker box.
--
Bob La Londe
CNC Molds N Stuff
On 1/8/2023 2:35 PM, Jim Wilkins wrote:
"Snag"Â wrote in message news:tpfbt0$3ufpe$1@dont-email.me...
  A neighbor's friend brought a small welding repair over for me .
It's an I beam that is the backbone of a PTO powered post hole auger .
But that's not what this post is about , this post is about OHMYGAWD I
love my new welder . The flange that carries the yoke that the auger
hangs on had fatigued and split from the web , First order was to pull
it back into position and tack it in place . Then vee one side and run
a bead then flip and grind down to fresh weld and lay in a couple of
passes - all on the lowest power setting . Welding 1/4" thick
reinforcing strips on both sides had it all the way up to half power .
I may never need to use my tombstone welder again ...
Snag
------------------
Flux core?
I've been debating selling mine. On the rare occasion when I really
might need to burn some 7018 for some thicker plate I have the AHP ACDC
Pulse TIG/Stick. I like running DC stick so much better than using the
AC cracker box.
"Snag"Â wrote in message news:tpflmq$3vdrl$1@dont-email.me...
Mine's probably worth more as scrap ... I've read that these IGBT
welding machines have a bit of a different current profile , had mine
for several years now and I've never even plugged the stinget cable into
the machine . My stick welding sucks and I avoid it when I can .
Snag
----------------------
I was terrible at stick welding until I took a night school class in it
and was shown the proper preparation and technique, and introduced to
7018 DC. I spent all 6 sessions practicing making and breaking welds
until finally I could fold one double without a crack. Then I built the
front end loader and sawmill.
It was just as helpful and more economical of steel to run many parallel beads across one piece of randomly shaped steel scrap instead of joining
two straight-edged pieces.
On 1/9/2023 10:50 AM, Jim Wilkins wrote:
"Snag"Â wrote in message news:tpflmq$3vdrl$1@dont-email.me...
Mine's probably worth more as scrap ... I've read that these IGBT
welding machines have a bit of a different current profile , had mine
for several years now and I've never even plugged the stinget cable into
the machine . My stick welding sucks and I avoid it when I can .
Snag
----------------------
I was terrible at stick welding until I took a night school class in
it and was shown the proper preparation and technique, and introduced
to 7018 DC. I spent all 6 sessions practicing making and breaking
welds until finally I could fold one double without a crack. Then I
built the front end loader and sawmill.
It was just as helpful and more economical of steel to run many
parallel beads across one piece of randomly shaped steel scrap instead
of joining two straight-edged pieces.
 I did that with the TIG . I should do a sheet or two with the stick ,
I may be able to do better now . I've been studying puddles ... and it
helped my MIG welding , may be it could help with stick too .
"Snag" wrote in message news:tpflmq$3vdrl$1@dont-email.me...
Mine's ...
----------------------
I was terrible at stick welding until I took a night school class in
it and was shown the proper preparation and technique, and introduced
to 7018 DC. I spent all 6 sessions practicing making and breaking
welds until finally I could fold one double without a crack. Then I
built the front end loader and sawmill.
It was just as helpful and more economical of steel to run many
parallel beads across one piece of randomly shaped steel scrap instead
of joining two straight-edged pieces.
"Richard Smith" wrote in message news:ly7cxt7ceq.fsf@void.com...
...
...
-------------------
I didn't realize how hide-bound the educational establishment was
until I started taking night classes with teachers who worked for a
living. Instead of worshipping the formal structure of, say, Calculus
they taught it as a useful tool, and finally I could understand it.
...
https://ecologyisnotadirtyword.com/2017/08/27/applied-vs-pure-its-all-ecology-at-the-end-of-the-day/
" ‘Pure’ scientists were often more disparaging of applied science
than the other way around. ...
"Richard Smith"Â wrote in message news:lyzgaosyk9.fsf@void.com...
There were all sorts of things where we knew "God's design"
and were therefore respectful of it.
eg. response
"If you as much of think of iron and titanium in the same thought they
form a brittle intermetallic phase"
Obviously that is superlative, but the direction of the conversation
can be inferred :-)
-----------------------
Huh?
https://science.jrank.org/pages/6852/Titanium-Uses.html
"By far the most important use of titanium is in making alloys. It is
the element most commonly added to steel because it increases the
strength and resistance to corrosion of steel."
"Richard Smith" wrote in message news:lyzgaosyk9.fsf@void.com...
There were all sorts of things where we knew "God's design"
and were therefore respectful of it.
eg. response
"If you as much of think of iron and titanium in the same thought they
form a brittle intermetallic phase"
Obviously that is superlative, but the direction of the conversation
can be inferred :-)
-----------------------
Huh?
https://science.jrank.org/pages/6852/Titanium-Uses.html
"By far the most important use of titanium is in making alloys. It is
the element most commonly added to steel because it increases the
strength and resistance to corrosion of steel."
"Richard Smith" wrote in message news:lyzgaosyk9.fsf@void.com...
There were all sorts of things where we knew "God's design"
and were therefore respectful of it.
eg. response
"If you as much of think of iron and titanium in the same thought they
form a brittle intermetallic phase"
Obviously that is superlative, but the direction of the conversation
can be inferred :-)
-----------------------
Huh?
https://science.jrank.org/pages/6852/Titanium-Uses.html
"By far the most important use of titanium is in making alloys. It is
the element most commonly added to steel because it increases the
strength and resistance to corrosion of steel."
I can barely understand a word of mathematics books for techniques I
have "re-invented" and used given a need.
When doing my welding engineering masters the two of us who were
welders - the poor Head of Department would rather have endured an
untreated case of an embarrassing socially transmitted condition than
have to talk with one of us.
On Wednesday, January 11, 2023 at 1:42:18 PM UTC-5, Richard Smith wrote:
I can barely understand a word of mathematics books for techniques I
have "re-invented" and used given a need.
Having been looking at your website and in particular at your thesis recently... yeah, I can tell. I mean, that "sixth-jumping" technique of numerical computation is brilliant. One could probably derive it from
the partial differential equation for diffusion (in a derivation that would involve making approximations at various points), and that would be theorists' way of doing it. But you just pulled it out of your hat, as
if it were obvious, which in a way it is. It's not the most efficient way
to do the computation, but it will do, and is simple and direct. (If you ever have that task again, look for a heat equation solver and pretend hydrogen content is "heat", the heat equation is the same as that
for diffusion.) In any case, a theorist would have made it sound more profound, but wouldn't have done it any better -- at least as regards the core algorithm.
On the other hand, your treatment of boundaries between regions with different diffusion coefficients really could have used a theorist's input, because the first thing to decide from a theoretical perspective is what
the boundary condition should be. And the usual boundary condition for diffusion is that the concentrations on each side of the boundary are
equal -- whereas you looked at your algorithm, whose process resulted
in (at the boundary) a sharp jump in concentrations, and took that as
given. It's not; you have a clever hack for changing the diffusion coefficient that works fine on either side of the boundary, but that hack should not be taken as an inevitable statement of what happens at the boundary. There are other possible hacks, such as changing the cell
size on the slower-diffusing side to be smaller, which would give no
jump.
Sometimes there can indeed be a sharp jump; for instance if one side
has a greater chemical affinity to the thing that is diffusing, then
there's an energy level difference across the boundary, and since it's
harder to go uphill than downhill the result is a jump in concentrations.
But in this case that seems unlikely since you still basically have steel
on both sides of the boundary: a hydrogen atom that wanders across
the boundary won't find much change in conditions. (On a basic physics level, the diffusion can't be purely a process of jumping from one site that traps hydrogen to another; there's got to be some wandering-around
between such sites, and it's the wandering-around that determines what
site it lands in.) A sharp jump in concentration can't absolutely be
ruled out, but shouldn't be assumed, either.
This doesn't affect the main results of your thesis, of course. I was reading
it because although I'd heard of hydrogen embrittlement, the fact that hydrogen actually could be observed bubbling out of a freshly welded
surface (under the right conditions) was new to me and intriguing.
Anyway, learning the theory of partial differential equations well
enough to use it takes a lot of time and effort, and no one can be
blamed for not doing so (unless of course that's what they're
being paid for).
When doing my welding engineering masters the two of us who were
welders - the poor Head of Department would rather have endured an
untreated case of an embarrassing socially transmitted condition than
have to talk with one of us.
"Their minds bred in and in, and were accordingly cursed with barrenness
and degeneracy. No extraneous beauty or vigor was engrafted on the
decaying stock. By an exclusive attention to one class of phenomena,
by an exclusive taste for one species of excellence, the human intellect
was stunted."
I think that quote sums it up.
---
Norman Yarvin
yarvin@yarchive.net
Norman - the reality at the time, in the early 1990's, was that these
German and Japanese Thermo-Mechanically Controlled-Processed plate High-Strength Low-Alloy steels were so superior, leaving "us" having
to buy these steels and put them through our pipe-mills while plate
capacity here stood idle.
The "sixth-jumping" technique came to me having read Adolf Fick's
original 1855 (?) scientific paper. It is wise. He knows most
"assumptions" on the way to formulating his "Fick's Laws" are not
going to be so in most realities,
(I believe you can see "Fickian Diffusion" if you use a radioactive
tracer isotope on one side of a boundary (same element; difference in
the nucleus not affecting chemical properties), and see it mix in time
and have a way to detect concentration of "origin-1" to "origin-2"
atoms by radioactivity) - other than that - no chance...)
I saw that if you have "an automatic computer" ("a computer") you
don't need to formulate differential equations.
By the way - when I did my Doctoral research back up to the late
1990's, it really wasn't then possible to solve in 3 dimensions for mathematical expressions for conductive heat flow and diffusion.
The computer memory requirement; the computing time.
You talk of "boundaries" and "boundary conditions". How could anyone
have prior knowledge of what to set this at???
I found scientific "papers" where solutions were presented which were mathematically correct but physically incorrect.
You talk about "hacks" - but this solution, which is the
implementation of a model, is "pure" - you know what it represents physically.
On Friday, January 20, 2023 at 3:09:54 AM UTC-5, Richard Smith wrote:
Norman - the reality at the time, in the early 1990's, was that these
German and Japanese Thermo-Mechanically Controlled-Processed plate
High-Strength Low-Alloy steels were so superior, leaving "us" having
to buy these steels and put them through our pipe-mills while plate
capacity here stood idle.
Has that improved? (Or has it gotten worse, with no longer even a
British attempt to compete?)
...
Diffusion of atoms is extremely important, thoroughly studied and
fairly easy to measure over distance and time in semiconductor
fabrication. I was on a team that designed and built the necessary instruments for automated production testing. The electrical
properties of Silicon are very sensitive to the concentration of trace amounts of other atoms. https://www.eeeguide.com/diffusion-process-in-ic-fabrication/
...
...
To me it's just "diffusion": with that sort of basic process -- particles wandering around randomly -- it's hard for there to be any other
governing law.
...
...
Diffusion of atoms is extremely important, thoroughly studied and
fairly easy to measure over distance and time in semiconductor
fabrication. I was on a team that designed and built the necessary instruments for automated production testing. The electrical
properties of Silicon are very sensitive to the concentration of trace amounts of other atoms. https://www.eeeguide.com/diffusion-process-in-ic-fabrication/
...
"Richard Smith" wrote in message news:lycz763kcp.fsf@void.com...
...
...
-------------------
Raman lidar.
-------------------
...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5090567/
"Only at higher temperatures are the values from different works
[diffusion rate measurements] close to each other; at room temperature differences in the order of three magnitudes are observed. This is a
direct result of the interaction of hydrogen dissolved interstitially
in the crystal lattice and lattice defects in the iron, such as
vacancies, foreign atoms, dislocations, grain boundaries, voids and
other defects. Most of these defect sites tend to react exothermally
with interstitial hydrogen, as opposed to the endothermic dissolution
of hydrogen in the lattice, and constitute traps for hydrogen uptake, respectively sources for hydrogen release. The effective diffusion coefficient of hydrogen in the presence of defect sites is always
smaller than that of ideally dissolved hydrogen in the defect-free
perfect crystalline lattice."
Is the rate of diffusion through a thin sheet relatable to the rate of diffusion the same distance into a solid?
For real-time measurement:
https://unisense.com/products/h2-microsensor/
For integrated measurement, hydrogen can reduce silver and copper
compounds to the metal, and increase the sensitivity of photo film.
Norman Yarvin writes:
Has that improved? (Or has it gotten worse, with no longer even aMy PhD research should have been subtitled
British attempt to compete?)
"To boldly go where no-one thought it a particularly good idea to go"
(parody on "Star Trek" upbeat theme)
and when I completed it, after the scientifically posed "Conclusions"
the common-language ultra-brief summary would have been
"You're screwed".
Norman Yarvin writes:
To me it's just "diffusion": with that sort of basic process -- particles
wandering around randomly -- it's hard for there to be any other
governing law.
...
No way!!!
"Random" is the problem - it is hardly likely to be so.
Then there are other things going on we absolutely do not know about. >"Asymmetric diffusion", where the rate the solute enters the solid
solvent does not match the rate the solute leaves the solid solvent,
was previously known and observed.
Even what we do know - that for treatments like cold-working steel the >product (multiplication) of solubility and diffusivity stays the same
with increasing cold-work (cold work increases - S increases; D
decreases) (the "permeability" - seen abundantly elsewhere in-support)
- which means that solubility and diffusivity must be dependent
variables on the same one underlying independent physical state - got
massive explosive vitriolic response when I counselled that at the
time about 20 years ago to someone dealing with hydrogen. Academics
who were absolutely livid at the suggestion which is to be seen right
there "exact" in experimental data.
On Sunday, January 22, 2023 at 5:43:55 AM UTC-5, Richard Smith wrote:
Norman Yarvin writes:
Has that improved? (Or has it gotten worse, with no longer even aMy PhD research should have been subtitled
British attempt to compete?)
"To boldly go where no-one thought it a particularly good idea to go"
(parody on "Star Trek" upbeat theme)
and when I completed it, after the scientifically posed "Conclusions"
the common-language ultra-brief summary would have been
"You're screwed".
That much I gathered. But there are a lot of things that can happen
in the world: sometimes failing British companies have been bought
by their German competitors and revamped.
...
you're making theoretical statements (trespassing on their turf) but
doing so using crude arguments: it makes them feel like they're under barbarian invasion.
...
Raman Lidar
{other detectors}
Your "Raman Lidar" would work for a thin sample extracted from eg. a
weld, at liquid nitrogen temperature (hydrogen is "condensed" on
"traps" and is immobile) and that sample suddenly brought back to >room-temperature.
You could have the laser beam scanning the sample - likely a
raster-pattern, plotting {rate of hydrogen evolution (inferred by
hydrogen concentration in the gas surrounding} vs {position (x-y >coordinates)}.
There is no guessing how well this would work (?).
https://en.wikipedia.org/wiki/Maxwell%E2%80%93Boltzmann_distribution
Einstein accepted that Quantum theory explained observed results but he didn't believe it was the real answer.
The "sixth-jumping" technique came to me having read Adolf Fick's...
original 1855 (?) scientific paper.
I saw that if you have "an automatic computer" ("a computer") you
don't need to formulate differential equations.
A person of Middle-Eastern origin showed me the computational method...
for solving mathematical integration ("calculus") approximately but achievably. But having seen that, my "sixth-jumping model" came to
me. My sixth-jumping model used as a general solution does have "convergence" with increasing discretisation, by the way, stating the obvious.
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