Microwave ovens
Ed Kaulakis
"Hugh Gibbons" <hgib...@x-remove-xaxs4u.net> wrote in message
news:hgibbons-ya0240800...@news.axs4u.net...
> The water molecules are little resonators.
Cite? Any H20 resonance at 2.45GHz will be fine.
The author of http://www.howstuffworks.com/microwave.htm doesn't seem to
know about resonance.
"A microwave oven uses microwaves to heat food. Microwaves are radio
waves. In the case of microwave ovens, the commonly used radio wave
frequency is roughly 2,500 megahertz (2.5 gigahertz). Radio waves in
this frequency range have an interesting property: they are absorbed by
water, fats and sugars. When they are absorbed they are converted
directly into atomic motion - heat. Microwaves in this frequency range
have another interesting property: they are not absorbed by most
plastics, glass or ceramics. Metal reflects microwaves, which is why
metal pans do not work well in a microwave oven."
***
A question that has puzzled many is "why don't the metal sides and the
metal screen in the door heat up". I'm glad you asked.
Like the parabolic dish of a satellite receiver, the relatively thick
and highly conductive walls of a microwave oven reflect radio-frequency
(RF) energy. The satellite dish focuses incoming energy on a receiver;
the oven walls reflect it back towards the source.
In the process, currents known as "eddy currents" flow in the walls.
Because the walls are thick and highly conductive, these currents have
little heating effect, since heating depends on the product of current
and resistance.
The same currents also "want" to flow in *thin* conductors exposed to
the RF energy. Conductors such as aluminum foil, or CDs. And they do.
Since the resistance varies inversely with the thickness there are much
larger resistance losses in these thin conductors. These losses turn up
as heat. A lot of heat in a very little metal. It gets hot. Really
really hot. Hijinx ensue.
Ed "this is much easier *with* calculus" Kaulakis
Nick Spalding
>
> "Hugh Gibbons" <hgib...@x-remove-xaxs4u.net> wrote in message
> news:hgibbons-ya0240800...@news.axs4u.net...
>
> > The water molecules are little resonators.
>
> Cite? Any H20 resonance at 2.45GHz will be fine.
>
> The author of http://www.howstuffworks.com/microwave.htm doesn't seem to
> know about resonance.
> "A microwave oven uses microwaves to heat food. Microwaves are radio
> waves. In the case of microwave ovens, the commonly used radio wave
> frequency is roughly 2,500 megahertz (2.5 gigahertz). Radio waves in
> this frequency range have an interesting property: they are absorbed by
> water, fats and sugars. When they are absorbed they are converted
> directly into atomic motion - heat. Microwaves in this frequency range
> have another interesting property: they are not absorbed by most
> plastics, glass or ceramics. Metal reflects microwaves, which is why
> metal pans do not work well in a microwave oven."
Ceramics heat very well in a microwave. I routinely use mine to warm
the plate off which I am going to eat my dinner - after 2 minutes by
itself in my 900W machine a 10 inch plate is nearly too hot to hold.
> A question that has puzzled many is "why don't the metal sides and the
> metal screen in the door heat up". I'm glad you asked.
They do heat up to some extent.
> Like the parabolic dish of a satellite receiver, the relatively thick
> and highly conductive walls of a microwave oven reflect radio-frequency
> (RF) energy. The satellite dish focuses incoming energy on a receiver;
> the oven walls reflect it back towards the source.
>
> In the process, currents known as "eddy currents" flow in the walls.
> Because the walls are thick and highly conductive, these currents have
> little heating effect, since heating depends on the product of current
> and resistance.
>
> The same currents also "want" to flow in *thin* conductors exposed to
> the RF energy. Conductors such as aluminum foil, or CDs. And they do.
> Since the resistance varies inversely with the thickness there are much
> larger resistance losses in these thin conductors. These losses turn up
> as heat. A lot of heat in a very little metal. It gets hot. Really
> really hot. Hijinx ensue.
True, provided the piece of foil is of a size comparable to the
wavelength of the radiation which is 12.24cm. Pieces half that size
or smaller barely get hot at all; pieces 10 to 12 cm long explode in a
matter of seconds.
--
Nick Spalding
Ed Kaulakis
"Nick Spalding" <spal...@iol.ie> wrote in message
news:8g725u0su01du0tp9...@4ax.com...
> the plate off which I am going to eat my dinner - after 2 minutes by
> itself in my 900W machine a 10 inch plate is nearly too hot to hold.
>
Most of my plates are vitreous ware. I splash a little water on and pile
them in the microwave to heat them for family meals. Doesn't work
without the water.
Stoneware is different. It has pores.
I have one cup that ALWAYS gets too hot to handle in the microwave. I
have many that don't. And I have a hypothesis about why this is.
So, I'll do an experiment. I'll bake that cup for a while, let it cool
down, and microwave it, to see if it still gets hot. My prediction is
that it won't. My hypothesis is that the source of the heating is
interstitial water, and that baking the piece will drive said water out
(till its next trip through the dishwasher). Results soon.
Ed "hypothetico-deductive" Kaulakis
Liz MacDonald
> I have one cup that ALWAYS gets too hot to handle in the microwave. I
> have many that don't. And I have a hypothesis about why this is.
>
> So, I'll do an experiment. I'll bake that cup for a while, let it cool
> down, and microwave it, to see if it still gets hot. My prediction is
> that it won't. My hypothesis is that the source of the heating is
> interstitial water, and that baking the piece will drive said water out
> (till its next trip through the dishwasher). Results soon.
Does Anyone Know if certain pigments resonate at microwave frequencies? I
have a set of four ceramic cups, each with a different color handle.
Experience has taught us not to nuke coffee in the one with the purple
handle, as the handle gets too hot to hold.
Liz "wakes you right up, though" M
danny burstein
>Does Anyone Know if certain pigments resonate at microwave frequencies? I
>have a set of four ceramic cups, each with a different color handle.
>Experience has taught us not to nuke coffee in the one with the purple
>handle, as the handle gets too hot to hold.
Isn't purple glazing the one that uses Uranium? Might explain the "heat"
>Liz "wakes you right up, though" M
And everyone else within a dozen or so kilometers...
--
_____________________________________________________
Knowledge may be power, but communications is the key
dan...@panix.com
[to foil spammers, my address has been double rot-13 encoded]
Leslie Marshall
Could be due to the metallic content of the pigment, in which case the heating
may be due to electromagnetic induction rather than molecular resonance.
I had a plate with a little gold trim on it that gave the most spectacular
light show when put in the microwave, with green sparks dancing on the
surface.
LRM
Ed Kaulakis
"Ed Kaulakis" <kaulaki...@pacbell.net> wrote in message
news:9wd48.546$Hj6....@typhoon.socal.rr.com...
> Stoneware is different. It has pores.
>
> I have one cup that ALWAYS gets too hot to handle in the microwave. I
> have many that don't. And I have a hypothesis about why this is.
>
> So, I'll do an experiment. I'll bake that cup for a while, let it
cool
> down, and microwave it, to see if it still gets hot. My prediction is
> that it won't. My hypothesis is that the source of the heating is
> interstitial water, and that baking the piece will drive said water
out
> (till its next trip through the dishwasher). Results soon.
I turned the suspect cup upside down and nuked it for 40 minutes. It
acquired coffee-colored stains not only where the glaze was visibly
missing on the base but also around the inside rim, where there was no
visible break in the glaze.
I put it aside to cool down, after first informing the children that it
was a hazard and not to touch it. Much to my surprise they complied.
When it had cooled down to room temperature I took it and another
randomly selected coffee cup and nuked them both for 90 seconds. The
(previously guaranteed to heat the handle) suspect cup came out
noticably cooler in the body and in the handle than did the random cup.
I conclude that whatever was causing the suspect cup to overheat was
dispelled by the prior extended heat treatment.
Further studies will be needed to unambiguously resolve whether the
dispelled species was water, dihydrogen monoxide, protonol, hydronium
hydroxide, or other even more exotic species. As all these chemicals are
extremely dangerous, accounting for significantly more annual deaths
worldwide than heroin, it is proposed that the research program should
be removed to a secluded place close to supplies of the raw materials.
After exhaustive search Bora Bora has been selected. Required additives
will be acquired from nearby Hawaii. It is estimated that this research
can be carried forward to the point of a preliminary report for
two-fifty, 'kay?
Ed "and reasonable & necessary, etc." Kaulakis
Ralph Jones
There are resonance effects, but not at the molecular level. They're
on a scale that is of the order of the dimensions of the oven. Two
pieces of wire of different length placed in the oven will heat up at
different rates, and you can calculate the difference if you know the
magnetron frequency -- using the same relations you use to calculate
the right length for an antenna.
The walls don't have to be thick; they could be made of Reynolds Wrap
if it weren't so fragile. Basically, the oven housing is a waveguide
that carries the radiation from the magnetron to the oven contents.
The amount of heat delivered depends on the impedance match between
the waveguide and the contents.
A big piece of meat forms something close to a perfect match, and gets
a maximum of heating. A cup of water is a much poorer match, and most
of the energy gets reflected back into the waveguide, and much of it
gets dissipated back at the magnetron.
An empty oven is the poorest possible match, and essentially all the
energy gets reflected back to the magnetron. This can overheat it,
which is why the instructions warn you not to run it empty. In
communication terms, it causes an unacceptably high standing wave
ratio.
John Gilmer
>
> Ceramics heat very well in a microwave. I routinely use mine to warm
> the plate off which I am going to eat my dinner - after 2 minutes by
> itself in my 900W machine a 10 inch plate is nearly too hot to hold.
Depends upon the "ceramic!"
Pure ceramics are just about transparent to microwaves.
I have a ceramic dish that was purpose built to absord microwave radiation,
however.
I have some cups that get very hot from the radiation. I suspect that the
"ceramic" is porous and thus contains water OR it has significant iron
compounds.
R H Draney
wrote:
>A big piece of meat forms something close to a perfect match, and gets
>a maximum of heating.
Not sure how often I'll get to use it, but MINE!...r
--
"A big piece of meat forms something close to a
perfect match, and gets a maximum of heating."
- Ralph Jones plays matchmaker
Ralph Jones
wrote:
>On Fri, 25 Jan 2002 16:40:35 GMT, Ralph Jones <ralp...@attbi.com>
>wrote:
>
>>A big piece of meat forms something close to a perfect match, and gets
>>a maximum of heating.
>
>Not sure how often I'll get to use it, but MINE!...r
I knew it would get a good home.
rj
Michael Schmidt
news:a2rrvt$nvh$1...@panix2.panix.com:
>
> Isn't purple glazing the one that uses Uranium? Might explain the
> "heat"
>
No. Uranium oxide is a lovely orange (if you like orange). Back in the
"friendly atom" 50's, in elementary school,we had the de rigour demo of
the
Geiger counter and stuff that would make it click. By _way_ far the hotest
item that my teacher had was an orange china plate, purchased at the local
five and dime.
Michael "and we survived shoe fitting fluoroscopes, too" Schmidt
Ralph Jones
wrote:
[snip]
>
>Michael "and we survived shoe fitting fluoroscopes, too" Schmidt
LOVED that thing! My mom did too...it was the only thing that would
get me to try things on without whining.
rj
R H Draney
wrote:
>On Sat, 26 Jan 2002 00:45:14 GMT, Michael Schmidt <msch...@attbi.com>
>wrote:
>>
>>Michael "and we survived shoe fitting fluoroscopes, too" Schmidt
>
>LOVED that thing! My mom did too...it was the only thing that would
>get me to try things on without whining.
Maybe I'm just an old fuddy-duddy, but when good parenting requires
the use of radiation, I have to think you've crossed some kind of
line....r
Hugh Gibbons
> Ed Kaulakis wrote, in <jt148.8406$Y6.6...@typhoon.socal.rr.com>:
>
> >
> > "Hugh Gibbons" <hgib...@x-remove-xaxs4u.net> wrote in message
> > news:hgibbons-ya0240800...@news.axs4u.net...
> >
> > > The water molecules are little resonators.
> >
> > Cite? Any H20 resonance at 2.45GHz will be fine.
My mistake. The molecular resonances are all higher. But liquid
water is lossy at that frequency. Vapor probably wouldn't absorb
it very well a tall.
> Ceramics heat very well in a microwave. I routinely use mine to warm
> the plate off which I am going to eat my dinner - after 2 minutes by
> itself in my 900W machine a 10 inch plate is nearly too hot to hold.
It depends on the ceramic. Some have lower losses at oven frequencies.
I found that china (porcelain) doesn't get hot, but my stonewear does[1].
But don't put your find china with the metal patterns plated on it in
the microwave![2] For everyday use, I switched to tempered glass plates,
because they also don't heat much in the microwave.
[1] My tests have always been with food on the plate.
[2] Saw and heard someone do that once. Not a pretty sight. Burned the
gold strips right off the plate.
Hugh Gibbons
<liz...@bellatlantic.net> wrote:
The glaze may be conductive or rather, more conductive than the others.
Thomas Prufer
wrote:
>>LOVED that thing! My mom did too...it was the only thing that would
>>get me to try things on without whining.
>
>Maybe I'm just an old fuddy-duddy, but when good parenting requires
>the use of radiation, I have to think you've crossed some kind of
>line....r
I'm fairly certain I saw a shoe fluoroscope in one of the Smithsonian
museums in Washington, D.C., with a note that the presumably last one
in operation was found in a shoe store in West Virginia in the 1990's.
Thomas Prufer
Thomas Prufer
Gibbons) wrote:
>The glaze may be conductive or rather, more conductive than the others.
I think I've actually seen this mentioned as a rough-and-ready test
for lead and other heavy metals in ceramic glazes.
Thomas Prufer
Ralph Jones
>On Sat, 26 Jan 2002 01:27:59 GMT, Ralph Jones <ralp...@attbi.com>
>wrote:
>
>>On Sat, 26 Jan 2002 00:45:14 GMT, Michael Schmidt <msch...@attbi.com>
>>wrote:
>>>
>>>Michael "and we survived shoe fitting fluoroscopes, too" Schmidt
>>
>>LOVED that thing! My mom did too...it was the only thing that would
>>get me to try things on without whining.
>
>Maybe I'm just an old fuddy-duddy, but when good parenting requires
>the use of radiation, I have to think you've crossed some kind of
>line....r
Ah, but Ritalin was no more than a dream then.
rj
Ulo Melton
wrote:
>I'm fairly certain I saw a shoe fluoroscope in one of the Smithsonian
>museums in Washington, D.C., with a note that the presumably last one
>in operation was found in a shoe store in West Virginia in the 1990's.
I didn't realize they were such elegant looking affairs until I went
looking for a picture of one:
<http://www.orau.com/ptp/collection/shoefittingfluor/shoe.htm>
Maybe they weren't all as chic as that one.
--
Ulo Melton (melt...@sewergator.com)
http://www.sewergator.com - Your Pipeline to Adventure
Joseph M. Shair
26 Jan 2002 00:45:14 GMT:
> dan...@panix.com (danny burstein) wrote in
> news:a2rrvt$nvh$1...@panix2.panix.com:
>
> >
> > Isn't purple glazing the one that uses Uranium? Might explain the
> > "heat"
> >
> No. Uranium oxide is a lovely orange (if you like orange). Back in the
> "friendly atom" 50's, in elementary school,we had the de rigour demo of
> the
> Geiger counter and stuff that would make it click. By _way_ far the hotest
> item that my teacher had was an orange china plate, purchased at the local
> five and dime.
ObKD(Radioactive)Moment:
Our Jr. High School (grades 7-9) Science Club was
doing its bit on radiation. We had plenty of items
which were slightly or moderately radioactive, but
nothing more so than uranium. I asked my father for
something highly radioactive to take in for use in a
demonstration. He lent me a 1 gram piece of radium
he had sitting around the office in a 2"x2"x2" lead
box wrapped in two sheets of 1/8" lead (to protect
against leakage from the crack where the box opened).
It wasn't of much value in the demonstration since it
pegged the needles on all the Geiger counters as soon
as it was brought into the room - still in the box and
wrapping. This did, however, convince Dad to no longer
store it in his office. (After learning of this, he
wondered if his hair loss had been related to having
had it sitting on a shelf about 3' behind his head for
5+ years.)
Joe "The far less radioactive iodine he also loaned
me made a much better demonstration." Shair
--
Remove invisible fnord words to reply.
There are things that are so serious that you can only
joke about them. -- Heisenberg
Simon Slavin
"Ed Kaulakis" <kaulaki...@pacbell.net> wrote:
> I put it aside to cool down, after first informing the children that it
> was a hazard and not to touch it. Much to my surprise they complied.
> When it had cooled down to room temperature I took it and another
> randomly selected coffee cup and nuked them both for 90 seconds.
Yeah: nuke the little bastards. And drink coffee while you're
watching them scream. It's the only way.
Simon.
--
http://www.hearsay.demon.co.uk | [One] thing that worries me about Bush and
No junk email please. | Blair's "war on terrorism" is: how will they
| know when they've won it ? -- Terry Jones
THE FRENCH WAS THERE
Ed Kaulakis
From: "Simon Slavin" <sla...@hearsay.demon.co.uk@localhost>
Newsgroups: alt.folklore.urban
Sent: Saturday, January 26, 2002 3:41 PM
Subject: Re: Microwave ovens
> In article <umf48.63$ru4....@typhoon.socal.rr.com>,
> "Ed Kaulakis" <kaulaki...@pacbell.net> wrote:
>
> > I put it aside to cool down, after first informing the children that
it
> > was a hazard and not to touch it. Much to my surprise they complied.
> > When it had cooled down to room temperature I took it and another
> > randomly selected coffee cup and nuked them both for 90 seconds.
>
> Yeah: nuke the little bastards. And drink coffee while you're
> watching them scream. It's the only way.
>
I imagine you've read his book, "The Man Who Mistook His Wife For A
Hat". Dysanaphoria cannot be cured, but it can help us unravel the
architecture of the working brane. And others. Oliver Sachs wants to
hear from you, Simon.
Ed "broken anaphoric reference provided as exemplar" Kaulakis
Lee Rudolph
>"Ed Kaulakis" <kaulaki...@pacbell.net> wrote:
>
>> I put it aside to cool down, after first informing the children that it
>> was a hazard and not to touch it. Much to my surprise they complied.
>> When it had cooled down to room temperature I took it and another
>> randomly selected coffee cup and nuked them both for 90 seconds.
>
>Yeah: nuke the little bastards. And drink coffee while you're
>watching them scream.
Don't forget the mango!
Lee "geeze, two alternative explanations for the
Stoned Babysitter in as many days" Rudolph
Kai Henningsen
> Maybe I'm just an old fuddy-duddy, but when good parenting requires
> the use of radiation, I have to think you've crossed some kind of
> line....r
You use neither light nor heat?
Kai
--
http://www.westfalen.de/private/khms/
"... by God I *KNOW* what this network is for, and you can't have it."
- Russ Allbery (r...@stanford.edu)
Rick Tyler
<sant...@adams.fnordnet> wrote:
>
>ObKD(Radioactive)Moment:
<snip>
>I asked my father for
>something highly radioactive to take in for use in a
>demonstration. He lent me a 1 gram piece of radium
>he had sitting around the office in a 2"x2"x2" lead
>box wrapped in two sheets of 1/8" lead (to protect
>against leakage from the crack where the box opened).
>
>It wasn't of much value in the demonstration since it
>pegged the needles on all the Geiger counters as soon
>as it was brought into the room - still in the box and
>wrapping. This did, however, convince Dad to no longer
>store it in his office.
My father had a piece of melted sand from the site of one of the
surface atomic bomb tests. At least until he had someone at his plant
test it with a geiger counter. I never saw it again...
-- Rick "My two kids share five eyes (none glass) between them" Tyler
__________________________________________________________________
"Ignorant voracity -- a wingless vulture -- can soar only into the
depths of ignominy." Patrick O'Brian
Lon Stowell
Rick Tyler <rht...@attbi.com> wrote:
>On Sat, 26 Jan 2002 14:19:18 -0600, Joseph M. Shair
><sant...@adams.fnordnet> wrote:
>>
>>ObKD(Radioactive)Moment:
><snip>
>>I asked my father for
>>something highly radioactive to take in for use in a
>>demonstration. He lent me a 1 gram piece of radium
>>he had sitting around the office in a 2"x2"x2" lead
>>box wrapped in two sheets of 1/8" lead (to protect
>>against leakage from the crack where the box opened).
>>
>>It wasn't of much value in the demonstration since it
>>pegged the needles on all the Geiger counters as soon
>>as it was brought into the room - still in the box and
>>wrapping. This did, however, convince Dad to no longer
>>store it in his office.
><snip>
>
>My father had a piece of melted sand from the site of one of the
>surface atomic bomb tests. At least until he had someone at his plant
>test it with a geiger counter. I never saw it again...
Dunno if there is any other area where a surface burst was done, but
several samples of Trinitite gathered before the army
bulldozed the old site were fairly radioactive in the
early 60's, but not as much as the autinite crystals picked up
from a few mines.
These are the type where there is roughly an inch or so of greenish
glass, merging into a sandy side.
Still didn't stick them in any pockets, kept them well wrapped..
Ed Kaulakis
"Lon Stowell" <lsto...@lenny.sfrn.dnai.com> wrote in message
news:a324c7$gqg$1...@bob.news.rcn.net...
> Dunno if there is any other area where a surface burst was done,
but
> several samples of Trinitite gathered before the army
> bulldozed the old site were fairly radioactive in the
> early 60's, but not as much as the autinite crystals picked up
> from a few mines.
>
> These are the type where there is roughly an inch or so of greenish
> glass, merging into a sandy side.
>
> Still didn't stick them in any pockets, kept them well wrapped..
It seems counterintuitive that a sample that had been cooling down,
radiologically speaking, for ~5x10e9 years would be hotter than one that
had been part of a chain reaction in historic times.
Were these "mines" in Nevada by any chance? The glass/sand surely
doesn't match any autinite descriptions I could find, although it is of
course very reminiscent of trinitite; is this a DoE in-joke?
As for caution, throw it to the winds! From a crystaloonie site:
AUTINITE - Green. Is said to foster courage, daring, new beginnings and
adventures. It is protective of those who are young and free and willing
to take a chance.
Ed "new age said to cause sudden nausea" Kaulakis
Charles Wm. Dimmick
> No. Uranium oxide is a lovely orange (if you like orange).
I think my mother still has a complete set of beautiful
earthenware china with that orange uranium glaze. Only
she has kept it packed away in a back corner of the basement
for the past 30 years, ever since she learned how dangerous
it might be to have it around. I want to say "Franconia Ware",
but my mind may be playing tricks on me.
Charles Wm. Dimmick
--
"And some rin up hill and down dale, knapping the
chucky stanes to pieces wi' hammers, like sae mony
road-makers run daft -- they say it is to see how
the warld was made!"
Charles Wm. Dimmick
> I didn't realize they were such elegant looking affairs until I went
> looking for a picture of one:
>
> <http://www.orau.com/ptp/collection/shoefittingfluor/shoe.htm>
Gosh that brings back memories. Looks just like the one I remember
from a visit to a shoe store in Elizabeth, New Jersey, circa 1945.
One of those stores which made/sold orthopaedic shoes, since I was
diagnosed with mild club foot in those days. Must have worked; I
had no trouble with my feet in later years.
Lara Hopkins
> I think my mother still has a complete set of beautiful
> earthenware china with that orange uranium glaze. Only
> she has kept it packed away in a back corner of the basement
> for the past 30 years, ever since she learned how dangerous
> it might be to have it around. I want to say "Franconia Ware",
> but my mind may be playing tricks on me.
Fiestaware?
http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/nucbuy.html
Lara
--
Lastly, that that us serf of lesson: a little critical spirit with
respect to information is undoubtedly not useless.
- Verily it is by Babelfish that we come at wisdom
XF©JRH
JG
> Indulging an inexplicable urge, Michael Schmidt broadcast on Sat,
> 26 Jan 2002 00:45:14 GMT:
> > dan...@panix.com (danny burstein) wrote in
> > news:a2rrvt$nvh$1...@panix2.panix.com:
> >
> > >
> > > Isn't purple glazing the one that uses Uranium? Might explain the
> > > "heat"
> > >
> > No. Uranium oxide is a lovely orange (if you like orange). Back in the
> > the Geiger counter and stuff that would make it click. By _way_ far the
> > hotest item that my teacher had was an orange china plate, purchased at
> > the local five and dime.
The plate probably contained tungsten. A Coleman Lantern filament is
pretty hot too, but harmless as long as you don't eat it.
> ObKD(Radioactive)Moment:
> Our Jr. High School (grades 7-9) Science Club was
> doing its bit on radiation. We had plenty of items
> which were slightly or moderately radioactive, but
> nothing more so than uranium. I asked my father for
> something highly radioactive to take in for use in a
> demonstration. He lent me a 1 gram piece of radium
> he had sitting around the office in a 2"x2"x2" lead
> box wrapped in two sheets of 1/8" lead (to protect
> against leakage from the crack where the box opened).
Let's see, the definition of a curie is 37 billion disintegrations per
second, or one gram of radium. Using the dose rate "rule of thumb"
for a curie, one curie of radium will read 825 millirem per hour at
one meter, unshielded. Now the Tenth Value Layer (TVL) of lead
required for radium is 4.6 cm[1]. So 2.25 inches (5.7 cm) will
provide a little less than a TVL plus an HVL, or a factor of 20 in
shielding. I estimate the dose rate was 825/20 ~ 40 mrem/hr at 1
meter, from your shielded box. Using the inverse square law as a
guide, there should have been radiation area signs posted within 6
meters of the box, where all persons entering would be required to
wear dosimetry devices to record their exposure. The radium would
have been rendered harmless by using ten HVLs of lead instead or 5.5
inches, twice as much. But those lead bricks get pretty heavy.
> It wasn't of much value in the demonstration since it
> pegged the needles on all the Geiger counters as soon
> as it was brought into the room - still in the box and
> wrapping. This did, however, convince Dad to no longer
> store it in his office. (After learning of this, he
> wondered if his hair loss had been related to having
> had it sitting on a shelf about 3' behind his head for
> 5+ years.)
For all practical purposes, the office was a radiation area (high
radiation area within 2 feet). Assuming that your Dad's head was
within one meter of the box for three hours a day, four days a week,
fifty weeks per year, for five years (a conservative estimate), that's
120 rem total accumulated exposure. The NRC maximum allowable dose
for radiation workers is 5 rem per year (usually only 10% of this).
Your Dad received almost 5 times that amount. Most cancer patients
don't lose there hair until they receive about 300-400 rem, I think?,
usually over a two week period. If they received that much (whole
body) instantaneously, it would most likely kill them. I don't think
that the exposure contributed to his hair loss, but it did increase
his chances of developing cancer later. How much increase in risk is
difficult to estimate. One study of radiation workers showed that
exposure of 1 rem over two years increased the number of cases of
cancer in the group from 1,600 per 100,000 to 1,601, or one additional
case above the normal background level. I doubt if this relationship
is linear but I don't think that your Dad's exposure was any worse
than say, smoking two packs of cigarettes a day for ten years.
> Joe "The far less radioactive iodine he also loaned
> me made a much better demonstration." Shair
Jer "I-131?, one millicurie is sufficient" ry
Joseph M. Shair
08:26:26 -0800:
> Joseph M. Shair <sant...@adams.fnordnet> wrote in message
> news:<MPG.16bccb3f6...@news.supernews.com>...
> > ... He lent me a 1 gram piece of radium
> > box wrapped in two sheets of 1/8" lead (to protect
> > against leakage from the crack where the box opened).
>
> Let's see, the definition of a curie is 37 billion disintegrations per
> second, or one gram of radium. Using the dose rate "rule of thumb"
> for a curie, one curie of radium will read 825 millirem per hour at
> one meter, unshielded.
We only had it unshielded for a few minutes so
everyone would have (probably their only) chance
to see radium and watch it fluoresce.
> Now the Tenth Value Layer (TVL) of lead
> required for radium is 4.6 cm[1]. So 2.25 inches (5.7 cm) will
> provide a little less than a TVL plus an HVL, or a factor of 20 in
> shielding. I estimate the dose rate was 825/20 ~ 40 mrem/hr at 1
> meter, from your shielded box.
My math isn't up to this, but it seems to me that
radiation from such a box has to pass through
(slightly less than) 1.25" of lead, rather than
the 2.25" used in the calculations - except for
where it only has to pass through .25". How does
that effect the calculations?
> Using the inverse square law as a
> guide, there should have been radiation area signs posted within 6
> meters of the box, where all persons entering would be required to
> wear dosimetry devices to record their exposure. The radium would
<hack/>
I doubt these regulations existed in 1958 or 59,
when this occurred and it was thought/taught that
exposures <~ 300 REM (not MREM) weren't particularly
dangerous. There were several film-type dosimeters
in the room, but they were all max'd out - afterwards,
anyway.
What I laughingly call my memory tells me we had to
get it about 50-60' away, with two thick walls
between the box and the counters, before it no
longer affected the background radiation level
noticeably.
> > Joe "The far less radioactive iodine he also loaned
> > me made a much better demonstration." Shair
>
> Jer "I-131?, one millicurie is sufficient" ry
Ya nye znaiyoo. It's been a few years and the radium
was much more dramatic.
Joe "Neechivoe." Shair
--
Remove invisible fnord words to reply.
Our meetings are held to discuss many problems which
would never arise if we held fewer meetings. -- ?
Charles Wm. Dimmick
>
> Charles Wm. Dimmick <cdim...@snet.net> wrote:
>
> > I think my mother still has a complete set of beautiful
> > earthenware china with that orange uranium glaze. Only
> > she has kept it packed away in a back corner of the basement
> > for the past 30 years, ever since she learned how dangerous
> > it might be to have it around. I want to say "Franconia Ware",
> > but my mind may be playing tricks on me.
>
> Fiestaware?
> http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/nucbuy.html
No. Definitely not. Much more of a pale orange-brown with streaks
of dark orange-brown. I will ask her next time I talk with her.
Lon Stowell
Ed Kaulakis <kaulaki...@pacbell.net> wrote:
>
>It seems counterintuitive that a sample that had been cooling down,
>radiologically speaking, for ~5x10e9 years would be hotter than one that
>had been part of a chain reaction in historic times.
not down by St. George. Pretty green crystals, sorry it
appeared confused with trinitite.
The Trinitite samples were from Trinity Site. I would guess
that most everything went upwards and outwards, but it was never
as radioactive as some of the naturally occurring stuff in
Utah area, of half the basements in Grand Junction. Not even
in the early 60's.
>
>Were these "mines" in Nevada by any chance? The glass/sand surely
>doesn't match any autinite descriptions I could find, although it is of
>course very reminiscent of trinitite; is this a DoE in-joke?
No, it is posting whilst watching Sopranos.
>
>As for caution, throw it to the winds! From a crystaloonie site:
>
>AUTINITE - Green. Is said to foster courage, daring, new beginnings and
>adventures. It is protective of those who are young and free and willing
>to take a chance.
>
>Ed "new age said to cause sudden nausea" Kaulakis
>
And hair loss. And children who look like Roseanne Barr crossed
with Joan Rivers...at birth.
Dustin Anderson
news:3C561020...@snet.net:
<snip>
> No. Definitely not. Much more of a pale orange-brown with streaks
> of dark orange-brown. I will ask her next time I talk with her.
I was told we wouldn't be discussing Fart Art on this BBS.
Michael Schmidt
> Ulo Melton wrote:
>
>> I didn't realize they were such elegant looking affairs until I went
>> looking for a picture of one:
>>
>> <http://www.orau.com/ptp/collection/shoefittingfluor/shoe.htm>
>
> Gosh that brings back memories. Looks just like the one I remember
> from a visit to a shoe store in Elizabeth, New Jersey, circa 1945.
> One of those stores which made/sold orthopaedic shoes, since I was
> diagnosed with mild club foot in those days. Must have worked; I
> had no trouble with my feet in later years.
>
Actually, what I remember was a far more handsome, mahogony finished
beauty with curved surfaces and a sort of "art deco meets the incredible
hulk" look. The one in the cited site looks rather like somebody indeed
built it in their garage - though they at least took pains to use the
available texture of the plywood. And I rather think that these items
dissappered because of the discovery that gratuitous use of penetrating
radiation on children was not a good long-term solution to poorly-fit
shoes, Though the fear of offending the dignity of the radiology
profession is a nice touch.
Michael "but everything about Fox's(1) was larger than life" Schmidt
(1) G. Fox & Co., the anchor (in the positive sense) of downtown Hartford,
CT USA before it (Hartford) imploded. Think Macy's or Wannamaker's at
their zenith...
Michael Schmidt
news:7e7a6dab.0201...@posting.google.com:
>
> The plate probably contained tungsten. A Coleman Lantern filament is
> pretty hot too, but harmless as long as you don't eat it.
>
No, the glaze on the plate contained uranium oxide. And lantern mantles
contain, or contained, thorium. See
http://www.vcds.dnd.ca/dsafeg/digest/11-00/art01_e.asp
I suspect, though am too lazy to research, that the PC mantles don't work
like the originals.
Conventional incandescent lamp ("a type") filaments are tungsten. And are
not redioactive. And yes, eating lantern mantles is probably unwise.
Michael "I'll also leave the "taste lousy" test to someone else" Schmidt
Brian Yeoh
> jgor...@hotmail.com (JG) wrote in
> > The plate probably contained tungsten. A Coleman Lantern filament is
> > pretty hot too, but harmless as long as you don't eat it.
> No, the glaze on the plate contained uranium oxide. And lantern mantles
> contain, or contained, thorium. See
> http://www.vcds.dnd.ca/dsafeg/digest/11-00/art01_e.asp
> I suspect, though am too lazy to research, that the PC mantles don't work
> like the originals.
> Conventional incandescent lamp ("a type") filaments are tungsten. And are
> not redioactive. And yes, eating lantern mantles is probably unwise.
> Michael "I'll also leave the "taste lousy" test to someone else" Schmidt
I draw the line at metal, thanggyuveddymuch.
Brian "now metal with _seasoning_..." Yeoh
--
"[...] your honor hath bene wrongfullie enformed, in sayinge he was cutt
in maney peeces, after his deathe -- for if he had bene cutt in many peces
, he could not a lived till the next morninge [...] -- which shewes he was
not cutt in verie many peeces!"
-- John Carey, defends himself from murder charges [The Steel Bonnets]
JG
> Indulging an inexplicable urge, JG broadcast on 28 Jan 2002
> 08:26:26 -0800:
> > Joseph M. Shair <sant...@adams.fnordnet> wrote in message
> > news:<MPG.16bccb3f6...@news.supernews.com>...
> <hack/>
> > > ... He lent me a 1 gram piece of radium
> > > he had sitting around the office in a 2"x2"x2" lead
> > > box wrapped in two sheets of 1/8" lead (to protect
> > > against leakage from the crack where the box opened).
> >
> > Let's see, the definition of a curie is 37 billion disintegrations per
> > second, or one gram of radium. Using the dose rate "rule of thumb"
> > for a curie, one curie of radium will read 825 millirem per hour at
> > one meter, unshielded.
>
> We only had it unshielded for a few minutes so
> everyone would have (probably their only) chance
> to see radium and watch it fluoresce.
That was worth the exposure, in my opinion. I've read several stories
about "accidents" that occurred during the '50's, in the early stages
of nuclear reactor research. In one demonstration, a scientist used a
screw driver to maneuver two hemispheres of plutonium closer together.
The scientist was demonstrating the increase in neutron flux as the
two hemispheres came closer together. But the screw driver slipped
and the two hemispheres slammed together causing the plutonium to go
critical (critical mass). Everybody in the room experienced a
beautiful blue flash as the neutron flux increased significantly. The
scientist conducting the demostration quickly separated the two
hemispheres with his hands. His actions saved everybody else in the
room, but not him. After that incident, there was a healthy respect
for keeping these subcritical experiments from getting out of control.
> > Now the Tenth Value Layer (TVL) of lead
> > required for radium is 4.6 cm[1]. So 2.25 inches (5.7 cm) will
> > provide a little less than a TVL plus an HVL, or a factor of 20 in
> > shielding. I estimate the dose rate was 825/20 ~ 40 mrem/hr at 1
> > meter, from your shielded box.
>
> My math isn't up to this, but it seems to me that
> radiation from such a box has to pass through
> (slightly less than) 1.25" of lead, rather than
> the 2.25" used in the calculations - except for
> where it only has to pass through .25". How does
> that effect the calculations?
That definitely reduces the shielding from a factor of 16-20 down to a
factor of 4. The lead Half Value Layer (HVL) for Radium is 1.4 cm.
Two HVLs is a about 1.1 inches and that's a factor of four. So the
shielded dose rate at one meter was 825/4 ~ 206 mrem/hr. An NRC high
radiation area is > 100 mrem/hr. As you can see, one curie of
anything is difficult to deal with radiologically. Sources like these
are usually stored in what is known as a pig, a 200-300 lb. lead
cylinder, about 5 inches thick. These sources are used to detect
cracks in welds or defects in metal pipes and joints. But workers
stand behind lead brick wall when the sources are removed from their
shelter.
<snip>
Jer "RadCon, class of '83" ry
JG
> Ulo Melton wrote:
>
> > I didn't realize they were such elegant looking affairs until I went
> > looking for a picture of one:
> >
> > <http://www.orau.com/ptp/collection/shoefittingfluor/shoe.htm>
>
> Gosh that brings back memories. Looks just like the one I remember
> from a visit to a shoe store in Elizabeth, New Jersey, circa 1945.
> One of those stores which made/sold orthopaedic shoes, since I was
> diagnosed with mild club foot in those days. Must have worked; I
> had no trouble with my feet in later years.
>
> Charles Wm. Dimmick
These devices delivered about 5 rem to the foot, compared with 10
millirem to the jaw with a modern dental x-ray. I doubt if the
exposure was harmful as extremities can handle a lot more radiation
than vital organs, but it's best to err on the side of safety.
Jer "SWIM[1]" ry
1. Stop the spill, Warn others, Isolate the area, Minimize your
exposure.
Michael Schmidt
news:7e7a6dab.02012...@posting.google.com:
> The scientist was demonstrating the increase in neutron flux as the
> two hemispheres came closer together. But the screw driver slipped
> and the two hemispheres slammed together causing the plutonium to go
> critical (critical mass). Everybody in the room experienced a
> beautiful blue flash as the neutron flux increased significantly. The
> scientist conducting the demostration quickly separated the two
> hemispheres with his hands. His actions saved everybody else in the
> room, but not him. After that incident, there was a healthy respect
> for keeping these subcritical experiments from getting out of control.
>
Fweep! (sticks whistle back in zebra-jersey pocket) This little vignette
tripped my vector detector; heck the poor thing is in convulsions and may
not recover. Reads like a passage out of pre 50s sci fi, it does. For
example:
1. Why did the neutron flux increase as the hemisperes were pushed
together? Criticality on a macro level is "increasing neutron flux without
(control) rod motion" (or some such) and on a micro level is "more
neutrons produced per generation than lost." Absent a moderator being
withdrawn, therefore there was criticality in the first sentence.
2. How did "neutron flux increased significantly" cause "a beautiful blue
flash?" Or any other flash? Neuts are subatomic particles, not photons.
And how did it hurt anybody? (quote from a death ray debunking: "if you
can see it, it can't hurt you")
3. A neutron generation is 10^-34 seconds (not sure about that number but
the order of magnitude on the exponenent is right). This bird was quick
indeed if he initiated a significant nuclear fission excursion and was
fast enough to terminate it with his hands before it burned out or went
outa sight (and burned out). Not to mention asbestos fingers.
Or to put all that in two words: cite, please.
Michael "Navy Nuclear Power Training Unit, 1970" Schmidt
Ed Kaulakis
"Michael Schmidt" <msch...@attbi.com> wrote in message
news:Xns91A585A6825...@204.127.68.17...
<snippage>
Responses intercalated.
> 1. Why did the neutron flux increase as the hemisperes were pushed
> together? Criticality on a macro level is "increasing neutron flux
without
> (control) rod motion" (or some such) and on a micro level is "more
> neutrons produced per generation than lost." Absent a moderator being
> withdrawn, therefore there was criticality in the first sentence.
Geometry changes can produce criticality - or do you think nuclear
weapons don't experience criticality because they have no control rods?
(]...............[)
Few neutrons emitted by either hemisphere reach the other.
(][)
More neutrons emitted by either hemisphere reach the other, increasing
potential for chain-reaction ("criticality").
> 2. How did "neutron flux increased significantly" cause "a beautiful
blue
> flash?" Or any other flash? Neuts are subatomic particles, not
photons.
Cerenkov radiation in the eyeball? (Shudder) In the air?
> And how did it hurt anybody? (quote from a death ray debunking: "if
you
> can see it, it can't hurt you")
Damn, I'm almost in the boat now, guess I'll go the rest of the way...
No, the blue flash didn't hurt anybody, but it *was* diagonostic of the
presence of energetic particles.
IIRC the room was only instrumented for neutron flux, and that pegged,
so all the radiation doses involved were estimated. Poor Slotkin got
over 1000 REM, estimated.
>
> 3. A neutron generation is 10^-34 seconds (not sure about that number
but
> the order of magnitude on the exponenent is right).
MINE!
> This bird was quick
> indeed if he initiated a significant nuclear fission excursion and was
> fast enough to terminate it with his hands before it burned out or
went
> outa sight (and burned out). Not to mention asbestos fingers.
Contrary to your expectations and mine, the assembly did not
self-disassemble. I'd love to know why not. Even more fortunate for the
others in the kiva, the hemispheres didn't weld together.
AFAIK there's never been an explanation of why he was doing this
experiment.
My understanding though is that weapons pits are designed to be just
barely subcritical. I conjecture the purpose of the experiment was to
determine how many more milligrams needed to be machined off *this* pit
before it met that spec.
Slotkin was lowering the upper hemisphere when he lost control of it and
it fell. The procedure was later changed so that the lower hemisphere
was raised, an inherently safer configuration. Relatively speaking.
> Or to put all that in two words: cite, please.
>
> Michael "Navy Nuclear Power Training Unit, 1970" Schmidt
Googled for "slotkin" and "plutonium", buried in cites. Go thou and do
likewise.
Ed "more than a billion, less than a googol" Kaulakis
--
Not sure about that number but the order
of magnitude on the exponenent is right
- Michael Schmidt approximates
Louise Bremner
> >> <http://www.orau.com/ptp/collection/shoefittingfluor/shoe.htm>
I saw them in shoe shops in London in the late fifties and maybe early
sixties, but my parents (a doctor and ex-nurse) wouldn't let me put my
feet in them, no matter how many times I said that the kids at school
said it's fun to watch your own toe-bones wriggling.
> And I rather think that these items dissappered because of the discovery
> that gratuitous use of penetrating radiation on children was not a good
> long-term solution to poorly-fit shoes
There was also concern about the lack of shielding around the
cabinet--the assistants in the stores were accumulating large doses long
after X-ray technicians had been made to go behind a heavy screen to
take each shot.
________________________________________________________________________
Louise "" Bremner (log at gol dot com)
If you want a reply by e-mail, don't write to my Yahoo address!
Brian Yeoh
> jgor...@hotmail.com (JG) wrote in
<tickling the dragon's tail account snipped>
> Fweep! (sticks whistle back in zebra-jersey pocket) This little vignette
> tripped my vector detector; heck the poor thing is in convulsions and may
> not recover. Reads like a passage out of pre 50s sci fi, it does. For
> example:
Precisely. Exactly right. 1946, to be precise
<snip objections>
> Or to put all that in two words: cite, please.
http://www.childrenofthemanhattanproject.org/FH/Section_Directory.htm
http://www.telefilm.gc.ca/en/prod/tv/tv99/164.htm
http://www.science.ca/scientists/scientistprofile.php?pID=290
http://www.cns-snc.ca/history/pioneers/slotin/slotin.html
In 1946, not everyone viewed nuclear power with quite the same horror as
we do now.
The last site is a bit more careful about describing the experiment.
Also, Louis Slotin wasn't the first to die from this type of experiment.
Brian "wasteful, wasteful, wasteful" Yeoh
Mitch Barrie
<kaulaki...@pacbell.net> wrote:
# "Michael Schmidt" <msch...@attbi.com> wrote:
# > Or to put all that in two words: cite, please.
#
# Googled for "slotkin" and "plutonium", buried in cites. Go thou and do
# likewise.
Googling for Slotin (not Slotkin) and Daghlian works too.
Mitch
JG
> On Tue, 29 Jan 2002, Michael Schmidt wrote:
>
> > jgor...@hotmail.com (JG) wrote in
>
> <tickling the dragon's tail account snipped>
>
> > Fweep! (sticks whistle back in zebra-jersey pocket) This little vignette
> > tripped my vector detector; heck the poor thing is in convulsions and may
> > not recover. Reads like a passage out of pre 50s sci fi, it does. For
> > example:
>
> Precisely. Exactly right. 1946, to be precise
>
> <snip objections>
>
> > Or to put all that in two words: cite, please.
>
> http://www.childrenofthemanhattanproject.org/FH/Section_Directory.htm
> http://www.telefilm.gc.ca/en/prod/tv/tv99/164.htm
> http://www.science.ca/scientists/scientistprofile.php?pID=290
> http://www.cns-snc.ca/history/pioneers/slotin/slotin.html
>
> In 1946, not everyone viewed nuclear power with quite the same horror as
> we do now.
>
> The last site is a bit more careful about describing the experiment.
Thanks Brian, I was writing from memory, unaware of the relevant
websites. I always found the "blue flash" part of the story
intriguing. The emmision of visible light may have been Cerenkov
induced but the exact mechanism is open to debate. I just figured
that the eye-witness accounts from the scientists, who are trained to
be objective observers, were good enough for me.
There was another story in our Radiological Fundamentals book that was
interesting. Maybe there is something on the web to vorify it. I
believe it happened at the LR1 reactor in Los Alamos. Workers were
performing maintenance on the reactor when the mechanism that raised
and lowered one of the control rods got stuck. These mechanisms were
designed to move the rods very slowly to prevent sudden changes in the
core exposure, hence the term "control rod." One worker decided to
unstick the rod by grabbing on with both hands and pulling. He managed
to free the rod but moved it several inches upward in the process.
The reactor went critical for a split second and created a steam
explosion that shot the control rod out of the reactor core. When
other workers went inside the reactor to look for their cow orker,
they found him stuck to the ceiling, impaled by the errant control
rod. And that just goes to show that activities like this can do far
worse than making one go blind.
Jer "spare the rod" ry
JG
> jgor...@hotmail.com (JG) wrote in
> news:7e7a6dab.0201...@posting.google.com:
>
> >
> > The plate probably contained tungsten. A Coleman Lantern filament is
> > pretty hot too, but harmless as long as you don't eat it.
>
> No, the glaze on the plate contained uranium oxide. And lantern mantles
> contain, or contained, thorium. See
Okay, I believe you. I'll keep a watch out for any of those
suspicious orange colored plates. I wonder, how hot were they?
> http://www.vcds.dnd.ca/dsafeg/digest/11-00/art01_e.asp
>
> I suspect, though am too lazy to research, that the PC mantles don't work
> like the originals.
>
> Conventional incandescent lamp ("a type") filaments are tungsten. And are
> not redioactive. And yes, eating lantern mantles is probably unwise.
>
> Michael "I'll also leave the "taste lousy" test to someone else" Schmidt
My understanding is that tungsten contains thorium. The Coleman
Lantern filaments can read 2,000 counts per minute (cpm) where the
normal background is 50 cpm. I suspect that incandescent lamp
filaments are too small to read above background levels. So in that
sense they are not radioactive. Many plates and cups contain
tungsten/thorium as well and can read 2-5 times above background. My
photosensitive glasses read about 125 cpm above background. A common
trick to scare the RacCon guy is to throw a bundle of tig welds onto
the frisking table. That will set the alarm off every time as they
contain tungsten/thorium too. Then there's the problem with hot air
samples. Check the patch again after half an hour, if it reads half
as much, it's Radon. If not, then there's an airborne contamination
problem. Fortunately, we never had a "problem." Sometimes the Radon
got pretty thick though, 10-50 times above normal background. As long
as it was naturally occurring, it was not a problem. But I always had
a problem with that assessment.
Jer "do you want me to frisk that?" ry
Ray Depew
: jgor...@hotmail.com (JG) wrote in
: news:7e7a6dab.0201...@posting.google.com:
: >
: > The plate probably contained tungsten. A Coleman Lantern filament is
: > pretty hot too, but harmless as long as you don't eat it.
: >
: No, the glaze on the plate contained uranium oxide.
I think if you search groups.google.com for "Fiesta Ware," with the date
knobbies turned appropriately, you will find multiple discussions about this
topic.
Fiesta Ware comes in many bright colors. Orange is one of them, and the
original bright orange pigment was uranium oxide.
--
Regards
Ray Depew ray_...@agilent.com
"I meant *exactly* what I typed. I was simply confused." - Mitch Barrie
Ray Depew
: My understanding is that tungsten contains thorium.
Come again? "Tungsten contains thorium"?
: That will set the alarm off every time as they
: contain tungsten/thorium too.
Not sure what this means. I keep thinking "W != Th", but it's more probable
that I misunderstood your words than that you're suggesting thorium is a
component of tungsten.
--
Regards
Ray
Nick Spalding
> My understanding is that tungsten contains thorium.
Your understanding is faulty. Tungsten is element 74 in the periodic
table in the lantharide series, Thorium is element 90, in the actinide
series. No relation at all.
--
Nick Spalding
Lee Ayrton
But are they six degrees apart?
Lee "You've never heard of cobalt thorium G" Ayrton
Chris Clarke
Nick Spalding <spal...@iol.ie> wrote:
True in the Mendeleevan sense, but I'm anxiously awaiting JG's
explanation, because he's usually pretty literate as regards the
physical sciences. My theory[1] is he'll point out something like "in
the real world, sodium chloride often contains magnesium and phosphorus
and calcium."
Chris "handwaving by proxy" Clarke
[1] [miss]
--
Chris Clarke | Editor, Faultline Magazine
www.faultline.org | California Environmental News and Information
Steve Smith
> There was another story in our Radiological Fundamentals book that was
> interesting. Maybe there is something on the web to vorify it. I
> believe it happened at the LR1 reactor in Los Alamos. Workers were
> performing maintenance on the reactor when the mechanism that raised
> and lowered one of the control rods got stuck. These mechanisms were
> designed to move the rods very slowly to prevent sudden changes in the
> core exposure, hence the term "control rod." One worker decided to
> unstick the rod by grabbing on with both hands and pulling. He managed
> to free the rod but moved it several inches upward in the process.
> The reactor went critical for a split second and created a steam
> explosion that shot the control rod out of the reactor core. When
> other workers went inside the reactor to look for their cow orker,
> they found him stuck to the ceiling, impaled by the errant control
> rod. And that just goes to show that activities like this can do far
> worse than making one go blind.
>
> Jer "spare the rod" ry
It was the SL-1 in Idaho Falls, Idaho, 2 or 3 January, 1961. Happened
pretty much as you described. There was a suggestion (dunno what
happened to it) that this was actually a murder-suicide.
The whole thing looks far too much like Chernobyl accident for comfort.
--
Steve Smith s...@aginc.net
Agincourt Computing http://www.aginc.net
"Truth is stranger than fiction because fiction has to make sense."
Michael Schmidt
news:7e7a6dab.02013...@posting.google.com:
>
> There was another story in our Radiological Fundamentals book that was
> interesting. Maybe there is something on the web to vorify it. I
> believe it happened at the LR1 reactor in Los Alamos. Workers were
> performing maintenance on the reactor when the mechanism that raised
> and lowered one of the control rods got stuck. These mechanisms were
> designed to move the rods very slowly to prevent sudden changes in the
> core exposure, hence the term "control rod." One worker decided to
> unstick the rod by grabbing on with both hands and pulling. He managed
> to free the rod but moved it several inches upward in the process.
> The reactor went critical for a split second and created a steam
> explosion that shot the control rod out of the reactor core. When
> other workers went inside the reactor to look for their cow orker,
> they found him stuck to the ceiling, impaled by the errant control
> rod. And that just goes to show that activities like this can do far
> worse than making one go blind.
>
Actually, it was SL-1 at the National Reactor Testing Station, roughly 60
miles south west of Idaho Falls, Idaho USA in 1961. One man was indeed
impaled by a control rod, which indeed was blown out of the reactor by
(guesswork by the post mortem) "prompt criticality(1)," possibly caused by
jerking loose a stuck rod during an elaborate, manually executed, pre-
startup rod-to-drive motor latching procedure. Two men who were in the
control room at the time died later of acute radiaton exposure. Apparently
a nurse who rode in the amblance with one of the men had sereious
radiation sickness but recovered(3). The SL-1 was an Army reactor,
designed to be air liftable to remote locations for power generation. The
incident put paid to the Army reactor program. "SL1 reactor" turned up a
bunch of hits on Google but the first three turned out to be anti-nuke
shit so I stopped reading. Those interested may want to try harder.
Michael "famous potatoes(2)" Schmidt
(1) Control rod insertion/withdrawal in a thermal(3) reactor causes
reactivity removal/insertion as a function of both the rod motion and the
first derivative (speed) of rod motion. That's why a "SCRAM" is so
effective as an emergency shutdowm mechanism; the control rods are all
driven into the core fast, sometimes assisted by springs.
(2) Idaho licence plates actually had that written on them (AFAIK, they
still do).
(3) The nurse was not mentioned in the Oficial Report of Investigation
film that we saw in 1970 but was relayed to us by the grayhead who
embell^W told us about it. It may be a UL.
Michael Schmidt
news:Pine.GSO.4.21.020130...@sea.ntplx.net:
>
>
> On or about Wed, 30 Jan 2002, Nick Spalding of spal...@iol.ie wrote:
>
>> JG wrote, in <7e7a6dab.02013...@posting.google.com>:
>>
>> > My understanding is that tungsten contains thorium.
>>
Research is a wonderful thing, even when I get stuck doing it. I had a
recollection that thoriated tungsten was an option in high-powered
transmitter tube filaments. I Googled thereon and no transmitter tubes but
durned if I did find (as suspected I must modestly admit) that thorium
(and cerium and lanthenum) are standard additives to tungsten-inert-gas
(TIG) electrodes to help arc ignition. (Could it be that's why mantle
lanterns also contain thorium?) So the statement is possibly correct - but
not naturally.
Michael "where do I pick up polish for my halo?" Schmidt
JG
Excellent research Michael and thanks for finding information on the
SL-1 incident. My Googling was unsuccessful as LR1 was not a relevant
key word. The story seemed too fantastic to be true, but why shouldn't
truth be stranger than fiction, after all, fiction must be
believable[1].
I Googled on "Coleman lantern filaments, tungsten, thorium" and found
this archive of a post to, of all froups, rec.crafts.glass[2]. And
you don't need to ring a bell to get a halo, just visit
weather-photography.com[3].
Jer "Tonight when I chase the dragon..." ry
1. Mark Twain
2. http://yarchive.net/nuke/thorium.html
3. http://www.weather-photography.com/Atmospheric_Optics/index.html
JG
> On or about Wed, 30 Jan 2002, Nick Spalding of spal...@iol.ie wrote:
>
> > JG wrote, in <7e7a6dab.02013...@posting.google.com>:
> >
> > > My understanding is that tungsten contains thorium.
> >
> > Your understanding is faulty. Tungsten is element 74 in the periodic
> > table in the lantharide series, Thorium is element 90, in the actinide
> > series. No relation at all.
>
> But are they six degrees apart?
>
Weel, the moon's orbit around the earth is inclined six degrees away
from the ecliptic.
Jer "naturally" ry
Leslie Marshall
wrote:
>In article <samg5ukrr4pcnfoja...@4ax.com>,
> Nick Spalding <spal...@iol.ie> wrote:
>
>> JG wrote, in <7e7a6dab.02013...@posting.google.com>:
>>
>> > My understanding is that tungsten contains thorium.
>>
>> Your understanding is faulty. Tungsten is element 74 in the periodic
>> table in the lantharide series, Thorium is element 90, in the actinide
>> series. No relation at all.
>
>True in the Mendeleevan sense, but I'm anxiously awaiting JG's
>explanation, because he's usually pretty literate as regards the
>physical sciences. My theory[1] is he'll point out something like "in
>the real world, sodium chloride often contains magnesium and phosphorus
>and calcium."
>
Um, even in the real world sodium chloride does not contain anything
except sodium and chlorine ions. Sodium chloride salts, however, may
contain compounds of magnesium , phoshorus, calcium and iodine.
Tungsten metals are usually alloys containing other metals to alter
their properties. For example, x-ray tube anodes are typically made
of tungsten with 10% rhenium.
LR "its elementary" M
.
Dr H
On Tue, 29 Jan 2002, Brian Yeoh wrote:
}http://www.cns-snc.ca/history/pioneers/slotin/slotin.html
Now that IS a hair-raising story.
Dr H
David Winsemius
the quantized rotational states of polar water molecules was fairly widely
understood to be the basis of microwave ovens.
Go to http://physics.nist.gov/cgi-bin/micro/table5/start.pl and put in H2O
in the empirical search list. I was surprised to see you questioning it. I
thought that the excitation of the quantized rotational states of polar
water molecules was fairly widely understood to be the basis of microwave
ovens.
MHz
22235.044
22235.077
22235.120
22235.253
22235.298
22307.670
203407.52 2
225896.720
Or see:
http://core.ecu.edu/phys/spraguem/environment/emfs/emf03.html
David.
Ed Kaulakis wrote:
>
> "Hugh Gibbons" <hgib...@x-remove-xaxs4u.net> wrote in message
> news:hgibbons-ya0240800...@news.axs4u.net...
>
> > The water molecules are little resonators.
>
> Cite? Any H20 resonance at 2.45GHz will be fine.
>
> The author of http://www.howstuffworks.com/microwave.htm doesn't seem to
> know about resonance.
> "A microwave oven uses microwaves to heat food. Microwaves are radio
> waves. In the case of microwave ovens, the commonly used radio wave
> frequency is roughly 2,500 megahertz (2.5 gigahertz). Radio waves in
> this frequency range have an interesting property: they are absorbed by
> water, fats and sugars. When they are absorbed they are converted
> directly into atomic motion - heat. Microwaves in this frequency range
> have another interesting property: they are not absorbed by most
> plastics, glass or ceramics. Metal reflects microwaves, which is why
> metal pans do not work well in a microwave oven."
>
> ***
>
> A question that has puzzled many is "why don't the metal sides and the
> metal screen in the door heat up". I'm glad you asked.
>
> Like the parabolic dish of a satellite receiver, the relatively thick
> and highly conductive walls of a microwave oven reflect radio-frequency
> (RF) energy. The satellite dish focuses incoming energy on a receiver;
> the oven walls reflect it back towards the source.
>
> In the process, currents known as "eddy currents" flow in the walls.
> Because the walls are thick and highly conductive, these currents have
> little heating effect, since heating depends on the product of current
> and resistance.
>
> The same currents also "want" to flow in *thin* conductors exposed to
> the RF energy. Conductors such as aluminum foil, or CDs. And they do.
> Since the resistance varies inversely with the thickness there are much
> larger resistance losses in these thin conductors. These losses turn up
> as heat. A lot of heat in a very little metal. It gets hot. Really
> really hot. Hijinx ensue.
>
> Ed "this is much easier *with* calculus" Kaulakis
Mike Holmans
>On Sat, 26 Jan 2002 10:20:55 +0100, Thomas Prufer <pru...@i-dial.de>
>wrote:
>
>>I'm fairly certain I saw a shoe fluoroscope in one of the Smithsonian
>>museums in Washington, D.C., with a note that the presumably last one
>>in operation was found in a shoe store in West Virginia in the 1990's.
>
>I didn't realize they were such elegant looking affairs until I went
>looking for a picture of one:
>
><http://www.orau.com/ptp/collection/shoefittingfluor/shoe.htm>
>
>Maybe they weren't all as chic as that one.
No, they weren't. The one they had in a shoe shop in Ilkley, Yorks,
UKoGBaNI in the late 60s was much smaller, and encased in some plastic
(in a very loose sense, in that I wouldn't swear it wasn't bakelite)
rather than varnished wood. And it was easy to see the image of your
own feet, whereas the one pictured makes me think you'd have to crane
your neck over a long way to see them, and I wasn't capable of that at
age nine.
Mike "you need feet" Holmans
Edward Rice
Michael Schmidt <msch...@attbi.com> wrote:
According to FAS, the deaths were /not/ due to radiation illness (and there
were three -- I read your description to mean two deaths but perhaps you
assumed that the impaled fellow was a third).
http://www.fas.org/nuke/trinity/accident/critical.htm
SL-1 EXCURSION
Idaho Falls, Idaho, Jan. 3, 1961
A nuclear excursion occurred within the reactor vessel,
resulting in extensive damage of the reactor core and room,
and in high radiation levels (approximately 500-1,000
rem/hr) within the reactor room.
At the time of the accident, a three-man crew was on the top
of the reactor assembling the control rod drive mechanisms
and housing. Thenuclear excursion, which resulted in an
explosion, was caused by manual withdrawal, by one or more,
of the maintenance crew, of the centralcontrol rod blade
from the core considerably beyond the limit specified in the
maintenance procedures.
Two members of the crew were killed instantly by the force
of the explosion, and the third man died within two hours
following the incident asa result of an injury to the head.
Of the several hundred people engaged in recovery
operations, 22 persons received radiation exposures in
therange of three to 27 rem gamma radiation total-body
exposure. The maximum whole-body beta radiation was 120 rem.
Some gaseous fission products, including radioactive iodine,
escaped to the atmosphere outside the building and were
carried downwind in anarrow plume. Particulate fission
material was largely confined to the reactor building, with
slight radioactivity in the immediate vicinity ofthe
building.
The total property loss was $4,350,000. (See TlD-5360,
Suppl. 4, p. 8; 1962 Nuclear Safety. Vol. 3, #3, p. 64.)
Idaho Falls had another "incident" (but without fatalities) three weeks
later, which may also have contributed to the Army's stepping back from
nuclear power research. And those were after a 1954 explosion and a 1955
core meltdown, both at Idaho Falls.
FYA, here's one I'd never heard of before (same cite/site):
FATAL INJURY ACCOMPANIES CRITICALITY ACCIDENT
Los Alamos, N. Mex., Dec. 30, 1958
The chemical operator introduced what was believed to be a
dilute plutonium solution from one tank into another known
to contain more plutonium in emulsion. Solids containing
plutonium were probably washed from the bottom of the first
tank with nitric acid and the resultant mixture of nitric
acid and plutonium-bearing solids was added to the tank
containing the emulsion. A criticality excursion occurred
immediately after starting the motor to a propeller type
stirrer at the bottom of the second tank.
The operator fell from the low stepladder on which he was
standing and stumbled out of the door into the snow. A
second chemical operator in an adjoining room had seen a
flash, which probably resulted from a short circuit when the
motor to the stirrer started, and went to the man's
assistance. The accident victim mumbled he felt as though he
was burning up. Because of this, it was assumed that there
had been a chemical accident with a probable acid or
plutonium exposure. There was no realization that a
criticality accident had occurred for a number of minutes.
The quantity of plutonium which actually was present in the
tank was about ten times more than was supposed to be there
at any time during the procedure.
The employee died 35 hours later from the effects of a
radiation exposure with the whole-body dose calculated to be
12,000 rem +.
Two other employees received radiation exposures of 134 and
53 rem, respectively. Property damage was negligible. (See
TID-5360, Suppl 2, p. 30; USAEC Serious Accidents Issue
#143, 1-22-59.)
Another mention of the SL-1 incident...
http://www.time.com/time/daily/chernobyl/860512.history.html
Dec. 12, 1952. Accidental removal of four control rods at an
experimental nuclear power reactor at Chalk River, Canada,
near Ottawa, led to a partial meltdown of the reactor's
uranium fuel core. A million gallons of radioactive water
accumulated inside, but there were no accident-related
injuries. Although negligible in comparison with last week's
Soviet accident, it was the first known major malfunction of
a nuclear power plant.
Oct. 7, 1957. Like the Chernobyl facility, the Windscale
Pile No. 1 plutonium-production plant north of Liverpool,
England, used graphite to slow down neutrons emitted during
nuclear fission. When workers discovered a fire in the
reactor, they sprayed it with carbon dioxide but failed to
quench the blaze. By the time the fire was put out with
water, radioactive material had contaminated 200 sq. mi. of
countryside. Officials banned the sale of milk from cows
grazing in the area for more than a month. The government
estimated that at least 33 cancer deaths could be traced to
the effects of the accident.
Jan. 3, 1961. A worker's error in removing control rods from
the core of the SL-1 military experimental reactor near
Idaho Falls caused a fatal steam explosion. Three servicemen
were killed, one of them by impalement on a control rod. The
deaths were the first fatalities in the history of U.S.
nuclear reactor operations.
Michael Schmidt
I can't imagine why this chestnut is still floating around but...
My statement is based upon an AEC post mortem which I viewed dring a 4 1/2
year tour at the National Reactor Testing Station. I stand by the
statements I made, as may hve been corrupted by memory, hence my reserch to
confirm it. I don't know what FAS is but you cite radiation in excerr of
1000 rem. well,
http://www.geocities.com/RainForest/Andes/6180/radiation_basics.html#Acute%
20Exposure
Says in part,
"Exposure to 1000-5000 REMS produces Central Nervous System Syndrome. The
death rate for this exposure range is 90-100%. The symptoms of Cerebral
Syndrome include: nausea, vomiting diarrhea, lethargy, tremors,
convulsions, confusion, stupor, coma and death within hours to days"
You may believe as you see fit, of course.
Cheers