On Fri, 17 Dec 2004 22:23:07 GMT, NSM wrote in
news:f%Iwd.1830$nN6.225@edtnps84:

"Nicolaas Hawkins" wrote in message
...

| perhaps you have noticed that you microwave oven door contains shock
| horror glass through which microwaves can pass

| Please explain to us the difference between ordinary glass and shock
| horror glass?

Like the difference between John McCain and George Bush?

Sorry, you'll have to translate that for me. I don't speak American.

--
Regards,
Nicolaas.


.... We are worthy of only as much respect as we are prepared to give
others.

"Franc Zabkar" bravely wrote to "All" (18 Dec 04 07:39:15)
--- on the heady topic of " new microwave oven with no seal?"

FZ From: Franc Zabkar

FZ On Fri, 17 Dec 2004 17:48:34 +1300, Lawrence D9Oliveiro
FZ put finger to keyboard and
FZ composed:

In article , "wave" wave@waving wrote:

I was talking about the brown hard rubber like material on the inside of the
door which I think use to be in all microwaves, certainly all the ones I
ever seen.

Rubber isn't going to stop microwaves, is it?

FZ Wouldn't a rubber seal exacerbate leakage issues? I mean, wouldn't it
FZ effectively *create* a gap through which microwaves could leak?

Maybe "metalized" silicon rubber is a good shield for microwaves?

A*s*i*m*o*v

.... Puddy-tat's not so bwave in Gwanny's microwave!

On 16 Dec 2004 03:56:34 GMT (FoulDragon) wrote:

A hollow circular arrangement, even helical, would only be an unstable
equilibrium. Any perturbation would cause it to collapse.

What if each strand was keystone shaped?

Well, that would certainly increase the stability, but I think you'd
still have trouble supporting it at each power pole. I could imagine
some kind of internal support at each support point, but that sounds
like a nightmare to install at every tower.

Adding the tongue and groove to the keyhole shape would be even
better, but you'd still be limited by the shear strength of the
tongue, which is not very great for copper or aluminum.

Does anyone know if any of this has actually been used, or was it just
someone's pipe dream?

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

"NSM" bravely wrote to "All" (18 Dec 04 00:01:10)
--- on the heady topic of " new microwave oven with no seal?"

NS From: "NSM"

NS "Allodoxaphobia" wrote in message
NS ...

NS | No steenkin' "rubber" seal on my 20 year old Monkey Ward microwave.
NS |
NS | Jonesy

NS Have we beaten this subject to death yet or would the other 100
NS million microwave owners like to chip in?

No chips in my microwave(s) door!

A*s*i*m*o*v

.... Bald spot? It's a solar panel for a sex machine.

"Nicolaas Hawkins" wrote in message
...

| And neither of them anything like as bad as some clown trying to pretend
| he/she/it is the moderator.

Then let us hope you never fall into that trap!

"Nicolaas Hawkins" wrote in message
...
| On Fri, 17 Dec 2004 22:23:07 GMT, NSM wrote in
| news:f%Iwd.1830$nN6.225@edtnps84:

| Like the difference between John McCain and George Bush?
|
| Sorry, you'll have to translate that for me. I don't speak American.

Like the difference between waking up with Diana Rigg or Margaret Thatcher?

N

On Fri, 17 Dec 2004 17:50:14 +1300 Lawrence D'Oliveiro
wrote:

In article ,
Jim Adney wrote:

A hollow circular arrangement, even helical, would only be an unstable
equilibrium. Any perturbation would cause it to collapse.

Tell that to your water pipes, your chimney, tubular car chassis
members, and all kinds of other hollow building components where
strength and lightness are both required.

Those are all solid parts, except possibly for the chimney. I
completely agree that solid tubular construction is one of the best
ways to go.

This discussion started with a collection of round wires arranged in a
circle, forming a kind of tubular structure to be used in a HV long
distance transmission line. Then someone suggested making the wires
flat with tongue and grooves, and finally someone suggested making the
wires keystone shaped. Each of these suggestions adds some stability
to the concept, but I'd still be surprised if it could be strung like
this and still just be supported occasionally by the usual HV
transmission towers. I'd be happy to be proven wrong, however.

I don't think my chimney, or yours, would hold up well if we tried to
lay it on its side and then lift it from the middle. ;-)

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

On Sat, 18 Dec 2004 04:42:49 GMT, NSM wrote in
news:dzOwd.2754$nN6.1832@edtnps84:

"Nicolaas Hawkins" wrote in message
...

| And neither of them anything like as bad as some clown trying to pretend
| he/she/it is the moderator.

Then let us hope you never fall into that trap!

In the immortal words of one Eliza Doolittle, "Not BLOODY likely!"

--
Regards,
Nicolaas.


.... Knowledge is good; it is better if we can use it to do good.

On Sat, 18 Dec 2004 04:42:49 GMT, NSM wrote in
news:dzOwd.2755$nN6.1886@edtnps84:

"Nicolaas Hawkins" wrote in message
...
| On Fri, 17 Dec 2004 22:23:07 GMT, NSM wrote in
| news:f%Iwd.1830$nN6.225@edtnps84:

| Like the difference between John McCain and George Bush?
|
| Sorry, you'll have to translate that for me. I don't speak American.

Like the difference between waking up with Diana Rigg or Margaret Thatcher?

N

Understood now.

--
Regards,
Nicolaas.


.... Children need models, not critics.

"Jim Adney" wrote in message
...
On Fri, 17 Dec 2004 17:50:14 +1300 Lawrence D'Oliveiro
wrote:

In article ,
Jim Adney wrote:

A hollow circular arrangement, even helical, would only be an unstable
equilibrium. Any perturbation would cause it to collapse.

Tell that to your water pipes, your chimney, tubular car chassis
members, and all kinds of other hollow building components where
strength and lightness are both required.

Those are all solid parts, except possibly for the chimney. I
completely agree that solid tubular construction is one of the best
ways to go.



Tubular chassis aren't solid, they're hollow tubes as the name implies, ask
anybody who's worked on race cars. For the weight, a hollow tube is stronger
than a solid rod, note that this is weight, not diameter, yes a solid rod of
the same diameter is stronger than a hollow one, but many times heavier.

"James Sweet" wrote in message
news:%e%wd.3594$rL3.1303@trnddc03...

| Tubular chassis aren't solid, they're hollow tubes as the name implies,
ask
| anybody who's worked on race cars. For the weight, a hollow tube is
stronger
| than a solid rod, note that this is weight, not diameter, yes a solid rod
of
| the same diameter is stronger than a hollow one, but many times heavier.

For a given weight of material, maximum strength is obtained by distributing
it over the greatest cross sectional area possible, up to the point at which
it becomes too thin to resist buckling.

N

On Sat, 18 Dec 2004 19:23:19 GMT "NSM" wrote:

For a given weight of material, maximum strength is obtained by distributing
it over the greatest cross sectional area possible, up to the point at which
it becomes too thin to resist buckling.

Interesting, I never thought of it that way. Of course it's only true
if you include the inner hollow as part of the cross section.

Your last clause is the gotcha. That point is the hard one to
determine. ;-)

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

"Jim Adney" wrote in message
...
| On Sat, 18 Dec 2004 19:23:19 GMT "NSM" wrote:
|
| For a given weight of material, maximum strength is obtained by
distributing
| it over the greatest cross sectional area possible, up to the point at
which
| it becomes too thin to resist buckling.
|
| Interesting, I never thought of it that way. Of course it's only true
| if you include the inner hollow as part of the cross section.
|
| Your last clause is the gotcha. That point is the hard one to
| determine. ;-)

That's why they pay engineers the big bucks. Hope the engineer for that new
French bridge got the math right!

N

"Jim Adney" wrote in message
...

| You're right, of course, but what I meant, was that a tube is a single
| piece, hence solid even though hollow. The preceeding discussion was
| of a "tube" made up of a bunch of separate strips.
|
| I don't think there are any race cars out there which use chassis made
| of tubes which consist of a bunch of separate strips. I think you'd
| agree that this would be a structural waste of effort.

The edge connections would inevitably be weak points. Didn't Titanic pop
many of her joints when she hit the berg?

N

"NSM" wrote in message news:Zgpxd.4117$nN6.1232@edtnps84...

"Jim Adney" wrote in message
...

| You're right, of course, but what I meant, was that a tube is a single
| piece, hence solid even though hollow. The preceeding discussion was
| of a "tube" made up of a bunch of separate strips.
|
| I don't think there are any race cars out there which use chassis made
| of tubes which consist of a bunch of separate strips. I think you'd
| agree that this would be a structural waste of effort.

The edge connections would inevitably be weak points. Didn't Titanic pop
many of her joints when she hit the berg?



IIRC the steel itself fractured, it had a high sulphur content and was
especially brittle in the frigid water.

In article ,
Adder wrote:

provided the gap between the door and chassis is small it will be safe

Early microwaves had a mechanical seal - a compressible wire mesh that was
squashed in the gap between door and frame to seal it. This was easily
damaged or torn right off. Modern microwaves have an electrical seal. The
door edge contains a quarter-wave "trap" (cavity) that runs right around the
door. Microwaves leaking down the gap between door and frame enter the
cavity, bounce back from its end and arrive at the opening to the cavity out
of phase with the waves entering, thus canceling each other. It's like a
"short circuit" for radio waves. The door still has to fit reasonably well,
hence the warnings about not using it if the door is warped or doesn't close
properly.

--
Don Hills (dmhills at attglobaldotnet) Wellington, New Zealand
It's ironic that people who are too smart to engage in politics
are governed by people who are not as smart.

In article dzOwd.2755$nN6.1886@edtnps84, "NSM" wrote:

"Nicolaas Hawkins" wrote in message
. ..
| On Fri, 17 Dec 2004 22:23:07 GMT, NSM wrote in
| news:f%Iwd.1830$nN6.225@edtnps84:

| Like the difference between John McCain and George Bush?
|
| Sorry, you'll have to translate that for me. I don't speak American.

Like the difference between waking up with Diana Rigg or Margaret Thatcher?

Like waking up with measles?

"Sorry, I woke up with a bad case of Diana Rigg this morning."
"Could be worse, you could have the Thatchers."

On Sat, 18 Dec 2004 19:23:19 GMT, "NSM" wrote:


"James Sweet" wrote in message
news:%e%wd.3594$rL3.1303@trnddc03...

| Tubular chassis aren't solid, they're hollow tubes as the name implies,
ask
| anybody who's worked on race cars. For the weight, a hollow tube is
stronger
| than a solid rod, note that this is weight, not diameter, yes a solid rod
of
| the same diameter is stronger than a hollow one, but many times heavier.

For a given weight of material, maximum strength is obtained by distributing
it over the greatest cross sectional area possible, up to the point at which
it becomes too thin to resist buckling.


This is only true for bending and compression where buckling is a
concern. For tension, however, the profile is irrelevant and the
stress is simply calculated as corss-sectional area / tension.
Ever see a power line in compression?

wrote in message
...
| On Sat, 18 Dec 2004 19:23:19 GMT, "NSM" wrote:
| For a given weight of material, maximum strength is obtained by
distributing
| it over the greatest cross sectional area possible, up to the point at
which
| it becomes too thin to resist buckling.

| This is only true for bending and compression where buckling is a
| concern. For tension, however, the profile is irrelevant and the
| stress is simply calculated as corss-sectional area / tension.
| Ever see a power line in compression?

But at some point as the tension increases vs. the wall thickness the tube
will neck in on itself.

N

On Mon, 20 Dec 2004 00:45:45 GMT "NSM" wrote:

The edge connections would inevitably be weak points. Didn't Titanic pop
many of her joints when she hit the berg?

I'm not a ship expert, but when I visited the Queen ??? in Long Island
many years ago, I was impressed by the construction of the hull. The
plates were mayby 4-6" thick and not all that big: no dimension much
over 16'. The joints were overlapped with big rivet heads every few
inches. The scale of the joinery boggled my mind.

I'm sure the Titanic must have been similar, yet it sank. I guess you
can bend/break anything if you have virtually infinite forces to play
with.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

On Mon, 20 Dec 2004 00:45:45 GMT "NSM" wrote:

That's why they pay engineers the big bucks. Hope the engineer for that new
French bridge got the math right!

Yeah, really! The photos I've seen look absolutely beautiful.

There's a much less challenging bridge in LeHavre that is still
gorgeous, as well as breathtaking when you realize how high you will
be going on it.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

On Mon, 20 Dec 2004 03:31:30 GMT "James Sweet"
wrote:

IIRC the steel itself fractured, it had a high sulphur content and was
especially brittle in the frigid water.

Are you sure you're not thinking of the WW II Liberty Ships? They had
some kind of cold transition problem, at least early in the war.

Someone else will have to fill in the details on that.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

"Jim Adney" wrote in message
...
On Mon, 20 Dec 2004 03:31:30 GMT "James Sweet"
wrote:

IIRC the steel itself fractured, it had a high sulphur content and was
especially brittle in the frigid water.

Are you sure you're not thinking of the WW II Liberty Ships? They had
some kind of cold transition problem, at least early in the war.

Someone else will have to fill in the details on that.



I did a quick Google search to refresh my memory, appears that high sulphur
as well as high phosphorus were at least contributing factors. Fascinating
at any rate.
http://dwb.unl.edu/Teacher/NSF/C10/C.../aa022800a.htm

"Jim Adney" wrote in message
...
| On Mon, 20 Dec 2004 00:45:45 GMT "NSM" wrote:
|
| That's why they pay engineers the big bucks. Hope the engineer for that
new
| French bridge got the math right!
|
| Yeah, really! The photos I've seen look absolutely beautiful.
|
| There's a much less challenging bridge in LeHavre that is still
| gorgeous, as well as breathtaking when you realize how high you will
| be going on it.

I wonder if it will be like the Mackinac Bridge in Northern Michigan where
people just freeze when they have to drive over it. "Each year hundreds of
drivers suffering from agoraphobia (fear of high places) seek help from
bridge personnel to drive their vehicles over the bridge for them". Some of
them hide in the rear with a blanket over their heads!

NM

On Thu, 23 Dec 2004 02:58:36 GMT, NSM wrote in
news:wvqyd.7902$uj2.869@clgrps12:

"Jim Adney" wrote in message
...
| On Mon, 20 Dec 2004 00:45:45 GMT "NSM" wrote:
|
|That's why they pay engineers the big bucks. Hope the engineer for that
new
|French bridge got the math right!
|
| Yeah, really! The photos I've seen look absolutely beautiful.
|
| There's a much less challenging bridge in LeHavre that is still
| gorgeous, as well as breathtaking when you realize how high you will
| be going on it.

I wonder if it will be like the Mackinac Bridge in Northern Michigan where
people just freeze when they have to drive over it. "Each year hundreds of
drivers suffering from agoraphobia (fear of high places) seek help from
bridge personnel to drive their vehicles over the bridge for them". Some of
them hide in the rear with a blanket over their heads!

NM

Agoraphobia is the fear of open spaces, not high places.

--
Regards,
Nicolaas.


.... The harm we do is more noticed than any good we do.

"Nicolaas Hawkins" wrote in message
...
| On Thu, 23 Dec 2004 02:58:36 GMT, NSM wrote in
| news:wvqyd.7902$uj2.869@clgrps12:

| I wonder if it will be like the Mackinac Bridge in Northern Michigan
where
| people just freeze when they have to drive over it. "Each year hundreds
of
| drivers suffering from agoraphobia (fear of high places) seek help from
| bridge personnel to drive their vehicles over the bridge for them". Some
of
| them hide in the rear with a blanket over their heads!
|
| NM
|
| Agoraphobia is the fear of open spaces, not high places.

It's a quote.

On Thu, 23 Dec 2004 19:07:39 GMT, NSM wrote in
news:%HEyd.13355$nN6.360@edtnps84:

"Nicolaas Hawkins" wrote in message
...
| On Thu, 23 Dec 2004 02:58:36 GMT, NSM wrote in
| news:wvqyd.7902$uj2.869@clgrps12:

| I wonder if it will be like the Mackinac Bridge in Northern Michigan
where
| people just freeze when they have to drive over it. "Each year hundreds
of
| drivers suffering from agoraphobia (fear of high places) seek help from
| bridge personnel to drive their vehicles over the bridge for them". Some
of
| them hide in the rear with a blanket over their heads!
|
| NM
|
| Agoraphobia is the fear of open spaces, not high places.

It's a quote.

Big deal. It is no less wrong because of that.

--
Regards,
Nicolaas.


.... We often don't appreciate what we have until we lose it. Don't wait
for that to happen.

On Tue, 21 Dec 2004 05:55:36 GMT wrote:

Ever see a power line in compression?

Only at the support points. ;-)

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

On Tue, 21 Dec 2004 06:41:31 GMT "NSM" wrote:

| This is only true for bending and compression where buckling is a
| concern. For tension, however, the profile is irrelevant and the
| stress is simply calculated as corss-sectional area / tension.
| Ever see a power line in compression?

But at some point as the tension increases vs. the wall thickness the tube
will neck in on itself.

But wouldn't a solid rod with the same cross sectional area would do
the same thing at the same time? After all, nothing will happen until
the tension/unit area reaches the plastic deformation range.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

"Nicolaas Hawkins" wrote in message
...
| Big deal. It is no less wrong because of that.

PLONK!

On Fri, 24 Dec 2004 03:11:53 GMT, NSM wrote in
news:ZNLyd.13599$nN6.6235@edtnps84:

"Nicolaas Hawkins" wrote in message
...
| Big deal. It is no less wrong because of that.

PLONK!

Thanks ... and up yours with a large pine cone - big end frst.