On Monday, October 10, 2022 at 11:44:28 PM UTC-5, Robert Woodward wrote:
> In article <rJKIn...@kithrup.com>,
> djh...@kithrup.com (Dorothy J Heydt) wrote:
>
> > In article <21b43580-c001-4c26...@googlegroups.com>,
> > Quadibloc <jsa...@ecn.ab.ca> wrote:
> > >On Monday, October 10, 2022 at 4:06:52 PM UTC-6, Dorothy J Heydt wrote:
> > >
> > >> So long as they don't start using Titanium structural members.
> > >> High current DC arc is one of the few ways you can light Titanium
> > >> on fire and if you think putting out Lithium battery fires is
> > >> hard...
> > >
> > >Magnesium, of course, catches fire quite easily. That's why it was
> > >used in flash bulbs.
> > >But when it is used to make light-weight metal items, it is usually
> > >alloyed with aluminum. This considerably reduces its tendency to
> > >catch fire.
> > >But it doesn't eleminate it completely, as was discovered when magnesium
> > >was first used to make racing cars. Shortly after, though, it was discovered
> > >that if you alloy magnesium with _calcium_, you can produce an alloy that
> > >will not catch fire.
> > >Surely it would also be possible to make Titanum alloys that do not pose
> > >a fire hazard?
> >
> > (Hal Heydt)
> > Possibly... I don't know if anyone has tried and what effect
> > alloying the Titanium has on its other properties. Magnesium is
> > fairly easy to ignite so there is a real incentive--if you want
> > to use it at all--to find safer alloys. Titanium is hard to
> > ignite, though if you manage to do it, it's all but impossible to
> > put out.
> There are not very many substances that can burn in an atmosphere of
> pure nitrogen.
>
Titanium will burn in nitrogen, carbon dioxide, or water. To smother burning
titanium use argon or helium.

Peter Wezeman
anti-social Darwinist

In article <48517ce0-f509-42e6-b072-221e865c4cfdn@googlegroups.com>,
peterwezeman@hotmail.com <peterwezeman@hotmail.com> wrote:
>On Monday, October 10, 2022 at 11:44:28 PM UTC-5, Robert Woodward wrote:
>> In article <rJKIn...@kithrup.com>,
>> djh...@kithrup.com (Dorothy J Heydt) wrote:
>>
>> > In article <21b43580-c001-4c26...@googlegroups.com>,
>> > Quadibloc <jsa...@ecn.ab.ca> wrote:
>> > >On Monday, October 10, 2022 at 4:06:52 PM UTC-6, Dorothy J Heydt wrote:
>> > >
>> > >> So long as they don't start using Titanium structural members.
>> > >> High current DC arc is one of the few ways you can light Titanium
>> > >> on fire and if you think putting out Lithium battery fires is
>> > >> hard...
>> > >
>> > >Magnesium, of course, catches fire quite easily. That's why it was
>> > >used in flash bulbs.
>> > >But when it is used to make light-weight metal items, it is usually
>> > >alloyed with aluminum. This considerably reduces its tendency to
>> > >catch fire.
>> > >But it doesn't eleminate it completely, as was discovered when magnesium
>> > >was first used to make racing cars. Shortly after, though, it was
>discovered
>> > >that if you alloy magnesium with _calcium_, you can produce an alloy that
>> > >will not catch fire.
>> > >Surely it would also be possible to make Titanum alloys that do not pose
>> > >a fire hazard?
>> >
>> > (Hal Heydt)
>> > Possibly... I don't know if anyone has tried and what effect
>> > alloying the Titanium has on its other properties. Magnesium is
>> > fairly easy to ignite so there is a real incentive--if you want
>> > to use it at all--to find safer alloys. Titanium is hard to
>> > ignite, though if you manage to do it, it's all but impossible to
>> > put out.
>> There are not very many substances that can burn in an atmosphere of
>> pure nitrogen.
>>
>Titanium will burn in nitrogen, carbon dioxide, or water. To smother burning
>titanium use argon or helium.

(Hal Heydt)
Unless you're working in an enclosed space, it's kind of hard to
get Helium to stick around to put the fire out.

On Mon, 10 Oct 2022 10:41:30 -0700 (PDT), "pete...@gmail.com"
<petertrei@gmail.com> wrote:

>On Monday, October 10, 2022 at 10:00:01 AM UTC-4, Chris Buckley wrote:
>> On 2022-10-10, Dimensional Traveler <dtr...@sonic.net> wrote:
>> > On 10/9/2022 5:50 PM, pete...@gmail.com wrote:
>> >> On Sunday, October 9, 2022 at 4:15:02 PM UTC-4, Lynn McGuire wrote:
>> >>> On 10/9/2022 2:54 AM, Charles Packer wrote:
>> >>>> On Sat, 08 Oct 2022 15:46:57 -0500, Lynn McGuire wrote:
>> >>>>
>> >>>>> Thanks for the review. We do have a tremendous visionary in today's
>> >>>>> society, Elon Musk. He has managed to build on the knowledge of others
>> >>>>> and is creating new knowledge of his own.
>> >>>>>
>> >>>>
>> >>>> And as the saying goes, "there's no such thing as bad publicity" for
>> >>>> the campaign to get people to switch to electric cars...
>> >>> Uh, not so fast there. “Electric vehicles are exploding from water
>> >>> damage after Hurricane Ian, Florida official warns”
>> >>>
>> >>> https://www.fox5ny.com/news/electric-vehicles-are-exploding-from-water-damage-after-hurricane-ian
>> >>
>> >> Lets see.
>> >>
>> >> It's Fox "News".
>> >> No numbers given.
>> >> Aside from a single video clip, nothing confirmable or checkable.
>> >> Opinions from CEI, which is about as regressive an advocate as possible.
>> >> Pro tobacco
>> >> Pro coal
>> >> Climate denialism
>> >> Opposing fuel efficiency.
>> >> Supporting big pharma
>> >> Funded Koch Bros and Tabacco industry, among others.
>> >>
>> >> https://www.sourcewatch.org/index.php/Competitive_Enterprise_Institute
>> >>
>> >> You call this article "fair and balanced"?
>> >>
>> > Yes, _Lynn_ does.
>> Hmmm... Who exactly is showing their bias and prejudice here?
>>
>> https://nbc-2.com/news/environment/2022/10/08/electric-vehicle-fires-spark-in-southwest-florida-following-hurricane-ian/
>>
>> According to North Collier Fire Rescue District, there have been
>> 10 EV fires in all of Collier County since Hurricane Ian.
>> “If you have one of these vehicles, and it was submerged in
>> saltwater storm surge, be sure to move it out of your garage and
>> call the manufacturer for the next steps,” the Cape Coral Fire
>> Department shared on their Facebook page.
>>
>> I fail to see how this is not a problem that people in Florida need
>> to be aware of.
>
>That's a much better article, and yes, it sounds like there's a problem.
>
>Lynn's article was much more of a hit piece, and going to CEI, and
>only CEI, for commentary was a very red flag.

I ended up actually reading the article and, for Fox, I found it
fairly tame: a gummint official/fire marshall warns about a series of
fires caused by the problem. The problem is that salt water corrodes
batteries, when can then catch on fire.

I'm not much in favor of Fox, but a lot of its local news (which this
looks to be) is really quite ordinary. In some cases, even mundane
("Cat rescued from tree" level).

>It's still a bit over the top - the affected cars aren't 'exploding'. They're
>catching fire, which is bad enough, and it certainly sounds like you
>don't want to keep an EV that's been flooded inside a garage.

The /headline/ is overdramatic, but the /article/ isn't. The use of
"explode", then, is probably clickbait. Note that the video title puts
"explode" in quotes.

>To get geeky, Tesla is moving to a 'Structural battery pack', in which the
>batter is hermetically sealed (and essentially unmaintainable once sealed).
>This will probably reduce the chance of water incursion

Sounds like a fine idea.

Too bad they didn't do it sooner.

>In normal use, Teslas catch fire at about 1/10th the rate per mile
>driven as ICE cars.

I don't doubt that.
--
"In this connexion, unquestionably the most significant
development was the disintegration, under Christian
influence, of classical conceptions of the family and
of family right."

On 10/11/2022 6:13 AM, Dimensional Traveler wrote:
> On 10/10/2022 9:47 PM, Lynn McGuire wrote:
>> On 10/10/2022 11:44 PM, Robert Woodward wrote:
>>> In article <rJKInL.96p@kithrup.com>,
>>>   djheydt@kithrup.com (Dorothy J Heydt) wrote:
>>>
>>>> In article <21b43580-c001-4c26-87d3-1cc2c1ad0ee3n@googlegroups.com>,
>>>> Quadibloc  <jsavard@ecn.ab.ca> wrote:
>>>>> On Monday, October 10, 2022 at 4:06:52 PM UTC-6, Dorothy J Heydt
>>>>> wrote:
>>>>>
>>>>>> So long as they don't start using Titanium structural members.
>>>>>> High current DC arc is one of the few ways you can light Titanium
>>>>>> on fire and if you think putting out Lithium battery fires is
>>>>>> hard...
>>>>>
>>>>> Magnesium, of course, catches fire quite easily. That's why it was
>>>>> used in flash bulbs.
>>>>> But when it is used to make light-weight metal items, it is usually
>>>>> alloyed with aluminum. This considerably reduces its tendency to
>>>>> catch fire.
>>>>> But it doesn't eleminate it completely, as was discovered when
>>>>> magnesium
>>>>> was first used to make racing cars. Shortly after, though, it was
>>>>> discovered
>>>>> that if you alloy magnesium with _calcium_, you can produce an
>>>>> alloy that
>>>>> will not catch fire.
>>>>> Surely it would also be possible to make Titanum alloys that do not
>>>>> pose
>>>>> a fire hazard?
>>>>
>>>> (Hal Heydt)
>>>> Possibly...  I don't know if anyone has tried and what effect
>>>> alloying the Titanium has on its other properties.  Magnesium is
>>>> fairly easy to ignite so there is a real incentive--if you want
>>>> to use it at all--to find safer alloys.  Titanium is hard to
>>>> ignite, though if you manage to do it, it's all but impossible to
>>>> put out.
>>>
>>> There are not very many substances that can burn in an atmosphere of
>>> pure nitrogen.
>>
>> How about five pounds of liquid plutonium in a bucket ?
>>
> I don't think "burning" is the appropriate word to describe what that does.

Going critical and emitting gamma ??? rays in all directions for years
is definitely burning. It is not combustion though.

Lynn

On Tuesday, October 11, 2022 at 11:06:52 AM UTC-5, Dorothy J Heydt wrote:
> In article <48517ce0-f509-42e6...@googlegroups.com>,
> peterw...@hotmail.com <peterw...@hotmail.com> wrote:
> >On Monday, October 10, 2022 at 11:44:28 PM UTC-5, Robert Woodward wrote:
> >> In article <rJKIn...@kithrup.com>,
> >> djh...@kithrup.com (Dorothy J Heydt) wrote:
> >>
> >> > In article <21b43580-c001-4c26...@googlegroups.com>,
> >> > Quadibloc <jsa...@ecn.ab.ca> wrote:
> >> > >On Monday, October 10, 2022 at 4:06:52 PM UTC-6, Dorothy J Heydt wrote:
> >> > >
> >> > >> So long as they don't start using Titanium structural members.
> >> > >> High current DC arc is one of the few ways you can light Titanium
> >> > >> on fire and if you think putting out Lithium battery fires is
> >> > >> hard...
> >> > >
> >> > >Magnesium, of course, catches fire quite easily. That's why it was
> >> > >used in flash bulbs.
> >> > >But when it is used to make light-weight metal items, it is usually
> >> > >alloyed with aluminum. This considerably reduces its tendency to
> >> > >catch fire.
> >> > >But it doesn't eleminate it completely, as was discovered when magnesium
> >> > >was first used to make racing cars. Shortly after, though, it was
> >discovered
> >> > >that if you alloy magnesium with _calcium_, you can produce an alloy that
> >> > >will not catch fire.
> >> > >Surely it would also be possible to make Titanum alloys that do not pose
> >> > >a fire hazard?
> >> >
> >> > (Hal Heydt)
> >> > Possibly... I don't know if anyone has tried and what effect
> >> > alloying the Titanium has on its other properties. Magnesium is
> >> > fairly easy to ignite so there is a real incentive--if you want
> >> > to use it at all--to find safer alloys. Titanium is hard to
> >> > ignite, though if you manage to do it, it's all but impossible to
> >> > put out.
> >> There are not very many substances that can burn in an atmosphere of
> >> pure nitrogen.
> >>
> >Titanium will burn in nitrogen, carbon dioxide, or water. To smother burning
> >titanium use argon or helium.
> (Hal Heydt)
> Unless you're working in an enclosed space, it's kind of hard to
> get Helium to stick around to put the fire out.

Argon is the better choice; it has an atomic weight of 40 and is
therefore approximately 40 percent denser than air despite being a
monatomic gas. Argon and helium are both produced by decay of
radioactive isotopes but helium is so light it flies off into space
propelled by sunlight and solar wind, but argon accumulates and
at present makes up one percent of the Earth's atmosphere. It is
extracted commercially in the course of producing liquid oxygen
and nitrogen from air, since argon has a boiling point between that
of oxygen and nitrogen.

Argon expended for firefighting is not really lost since it just rejoins
the atmospheric stockpile. One of the main uses for argon is to
release it from a nozzle surrounding an arc welder to shield the
still-hot weld from air for such tasks as welding titanium. Within
seconds the weld is too cool to react.

Peter Wezeman
anti-social Darwinist

On Tue, 11 Oct 2022 04:13:59 -0700, Dimensional Traveler
<dtravel@sonic.net> wrote:

>On 10/10/2022 9:47 PM, Lynn McGuire wrote:
>> On 10/10/2022 11:44 PM, Robert Woodward wrote:
>>> In article <rJKInL.96p@kithrup.com>,
>>>   djheydt@kithrup.com (Dorothy J Heydt) wrote:
>>>
>>>> In article <21b43580-c001-4c26-87d3-1cc2c1ad0ee3n@googlegroups.com>,
>>>> Quadibloc  <jsavard@ecn.ab.ca> wrote:
>>>>> On Monday, October 10, 2022 at 4:06:52 PM UTC-6, Dorothy J Heydt wrote:
>>>>>
>>>>>> So long as they don't start using Titanium structural members.
>>>>>> High current DC arc is one of the few ways you can light Titanium
>>>>>> on fire and if you think putting out Lithium battery fires is
>>>>>> hard...
>>>>>
>>>>> Magnesium, of course, catches fire quite easily. That's why it was
>>>>> used in flash bulbs.
>>>>> But when it is used to make light-weight metal items, it is usually
>>>>> alloyed with aluminum. This considerably reduces its tendency to
>>>>> catch fire.
>>>>> But it doesn't eleminate it completely, as was discovered when
>>>>> magnesium
>>>>> was first used to make racing cars. Shortly after, though, it was
>>>>> discovered
>>>>> that if you alloy magnesium with _calcium_, you can produce an alloy
>>>>> that
>>>>> will not catch fire.
>>>>> Surely it would also be possible to make Titanum alloys that do not
>>>>> pose
>>>>> a fire hazard?
>>>>
>>>> (Hal Heydt)
>>>> Possibly...  I don't know if anyone has tried and what effect
>>>> alloying the Titanium has on its other properties.  Magnesium is
>>>> fairly easy to ignite so there is a real incentive--if you want
>>>> to use it at all--to find safer alloys.  Titanium is hard to
>>>> ignite, though if you manage to do it, it's all but impossible to
>>>> put out.
>>>
>>> There are not very many substances that can burn in an atmosphere of
>>> pure nitrogen.
>>
>> How about five pounds of liquid plutonium in a bucket ?
>>
>I don't think "burning" is the appropriate word to describe what that does.

I thought critical mass for plutonium was about 11-12 lbs but no
question sub-critical amounts could generate far more than the
"normal" amount of radiation and depending on the amount could easily
be lethal even if not explosively so.

On Tue, 11 Oct 2022 13:03:17 -0500, Lynn McGuire
<lynnmcguire5@gmail.com> wrote:

>>>> There are not very many substances that can burn in an atmosphere of
>>>> pure nitrogen.
>>>
>>> How about five pounds of liquid plutonium in a bucket ?
>>>
>> I don't think "burning" is the appropriate word to describe what that does.
>
>Going critical and emitting gamma ??? rays in all directions for years
>is definitely burning. It is not combustion though.
>
Even if plutonium was not radioactive at all it is a poisonous metal -
one of the most toxic.

However there's nothing like a dose of concentrated radiation to
really spoil your day!

On Tuesday, October 11, 2022 at 8:05:46 AM UTC-6, peterwezeman@hotmail.com wrote:
> On Monday, October 10, 2022 at 11:44:28 PM UTC-5, Robert Woodward wrote:

> > There are not very many substances that can burn in an atmosphere of
> > pure nitrogen.

> Titanium will burn in nitrogen, carbon dioxide, or water. To smother burning
> titanium use argon or helium.

Aside from helium being lighter than air and all that, wouldn't neon also work,
being less reactive than argon, but more reactive than helium? And are you
claiming that titanium will burn in an atmosphere of pure krypton or xenon?

Having heard of xenon fluoride, I have no doubt that, say, chlorine trifluoride
would, surrounded by an atmosphere of pure nitrogen, burn the nitrogen. What
it would do if it met titanium hardly bears thinking about, it seems.

John Savard

In article <qs1dkhl5r1irirnarksk5lbsjuq8ptvtju@4ax.com>,
The Horny Goat <lcraver@home.ca> wrote:
>On Tue, 11 Oct 2022 04:13:59 -0700, Dimensional Traveler
><dtravel@sonic.net> wrote:
>
>>On 10/10/2022 9:47 PM, Lynn McGuire wrote:
>>> On 10/10/2022 11:44 PM, Robert Woodward wrote:
>>>> In article <rJKInL.96p@kithrup.com>,
>>>> � djheydt@kithrup.com (Dorothy J Heydt) wrote:
>>>>
>>>>> In article <21b43580-c001-4c26-87d3-1cc2c1ad0ee3n@googlegroups.com>,
>>>>> Quadibloc� <jsavard@ecn.ab.ca> wrote:
>>>>>> On Monday, October 10, 2022 at 4:06:52 PM UTC-6, Dorothy J Heydt wrote:
>>>>>>
>>>>>>> So long as they don't start using Titanium structural members.
>>>>>>> High current DC arc is one of the few ways you can light Titanium
>>>>>>> on fire and if you think putting out Lithium battery fires is
>>>>>>> hard...
>>>>>>
>>>>>> Magnesium, of course, catches fire quite easily. That's why it was
>>>>>> used in flash bulbs.
>>>>>> But when it is used to make light-weight metal items, it is usually
>>>>>> alloyed with aluminum. This considerably reduces its tendency to
>>>>>> catch fire.
>>>>>> But it doesn't eleminate it completely, as was discovered when
>>>>>> magnesium
>>>>>> was first used to make racing cars. Shortly after, though, it was
>>>>>> discovered
>>>>>> that if you alloy magnesium with _calcium_, you can produce an alloy
>>>>>> that
>>>>>> will not catch fire.
>>>>>> Surely it would also be possible to make Titanum alloys that do not
>>>>>> pose
>>>>>> a fire hazard?
>>>>>
>>>>> (Hal Heydt)
>>>>> Possibly...� I don't know if anyone has tried and what effect
>>>>> alloying the Titanium has on its other properties.� Magnesium is
>>>>> fairly easy to ignite so there is a real incentive--if you want
>>>>> to use it at all--to find safer alloys.� Titanium is hard to
>>>>> ignite, though if you manage to do it, it's all but impossible to
>>>>> put out.
>>>>
>>>> There are not very many substances that can burn in an atmosphere of
>>>> pure nitrogen.
>>>
>>> How about five pounds of liquid plutonium in a bucket ?
>>>
>>I don't think "burning" is the appropriate word to describe what that does.
>
>I thought critical mass for plutonium was about 11-12 lbs but no
>question sub-critical amounts could generate far more than the
>"normal" amount of radiation and depending on the amount could easily
>be lethal even if not explosively so.

(Hal Heydt)
To the the best of my knowledge, it isn't a matter of critical mass
with Pu-239, so much as critical density. That's why a "gun"
type bomb (fire a core into a donut) works for U-235, but not
Pu-239. For Pu-239 you have the enormously more difficult task
of creating a spherical compression wave front to slam the pieces
together hard enough to get the density up to the point that you
get a--briefly--sustained fission reaction. It takes precisely
shaped explosive lenses with microsecond detonation timing.
Tough to do with the equipment available in 1945.

On 10/12/2022 4:25 AM, The Horny Goat wrote:
> On Tue, 11 Oct 2022 04:13:59 -0700, Dimensional Traveler
> <dtravel@sonic.net> wrote:
>
>> On 10/10/2022 9:47 PM, Lynn McGuire wrote:
>>> On 10/10/2022 11:44 PM, Robert Woodward wrote:
>>>> In article <rJKInL.96p@kithrup.com>,
>>>>   djheydt@kithrup.com (Dorothy J Heydt) wrote:
>>>>
>>>>> In article <21b43580-c001-4c26-87d3-1cc2c1ad0ee3n@googlegroups.com>,
>>>>> Quadibloc  <jsavard@ecn.ab.ca> wrote:
>>>>>> On Monday, October 10, 2022 at 4:06:52 PM UTC-6, Dorothy J Heydt wrote:
>>>>>>
>>>>>>> So long as they don't start using Titanium structural members.
>>>>>>> High current DC arc is one of the few ways you can light Titanium
>>>>>>> on fire and if you think putting out Lithium battery fires is
>>>>>>> hard...
>>>>>>
>>>>>> Magnesium, of course, catches fire quite easily. That's why it was
>>>>>> used in flash bulbs.
>>>>>> But when it is used to make light-weight metal items, it is usually
>>>>>> alloyed with aluminum. This considerably reduces its tendency to
>>>>>> catch fire.
>>>>>> But it doesn't eleminate it completely, as was discovered when
>>>>>> magnesium
>>>>>> was first used to make racing cars. Shortly after, though, it was
>>>>>> discovered
>>>>>> that if you alloy magnesium with _calcium_, you can produce an alloy
>>>>>> that
>>>>>> will not catch fire.
>>>>>> Surely it would also be possible to make Titanum alloys that do not
>>>>>> pose
>>>>>> a fire hazard?
>>>>>
>>>>> (Hal Heydt)
>>>>> Possibly...  I don't know if anyone has tried and what effect
>>>>> alloying the Titanium has on its other properties.  Magnesium is
>>>>> fairly easy to ignite so there is a real incentive--if you want
>>>>> to use it at all--to find safer alloys.  Titanium is hard to
>>>>> ignite, though if you manage to do it, it's all but impossible to
>>>>> put out.
>>>>
>>>> There are not very many substances that can burn in an atmosphere of
>>>> pure nitrogen.
>>>
>>> How about five pounds of liquid plutonium in a bucket ?
>>>
>> I don't think "burning" is the appropriate word to describe what that does.
>
> I thought critical mass for plutonium was about 11-12 lbs but no
> question sub-critical amounts could generate far more than the
> "normal" amount of radiation and depending on the amount could easily
> be lethal even if not explosively so.

You are correct. I should have used gallons instead of pounds.

Lynn

On 10/12/2022 11:45 AM, Dorothy J Heydt wrote:
> In article <qs1dkhl5r1irirnarksk5lbsjuq8ptvtju@4ax.com>,
> The Horny Goat <lcraver@home.ca> wrote:
>> On Tue, 11 Oct 2022 04:13:59 -0700, Dimensional Traveler
>> <dtravel@sonic.net> wrote:
>>
>>> On 10/10/2022 9:47 PM, Lynn McGuire wrote:
>>>> On 10/10/2022 11:44 PM, Robert Woodward wrote:
>>>>> In article <rJKInL.96p@kithrup.com>,
>>>>>   djheydt@kithrup.com (Dorothy J Heydt) wrote:
>>>>>
>>>>>> In article <21b43580-c001-4c26-87d3-1cc2c1ad0ee3n@googlegroups.com>,
>>>>>> Quadibloc  <jsavard@ecn.ab.ca> wrote:
>>>>>>> On Monday, October 10, 2022 at 4:06:52 PM UTC-6, Dorothy J Heydt wrote:
>>>>>>>
>>>>>>>> So long as they don't start using Titanium structural members.
>>>>>>>> High current DC arc is one of the few ways you can light Titanium
>>>>>>>> on fire and if you think putting out Lithium battery fires is
>>>>>>>> hard...
>>>>>>>
>>>>>>> Magnesium, of course, catches fire quite easily. That's why it was
>>>>>>> used in flash bulbs.
>>>>>>> But when it is used to make light-weight metal items, it is usually
>>>>>>> alloyed with aluminum. This considerably reduces its tendency to
>>>>>>> catch fire.
>>>>>>> But it doesn't eleminate it completely, as was discovered when
>>>>>>> magnesium
>>>>>>> was first used to make racing cars. Shortly after, though, it was
>>>>>>> discovered
>>>>>>> that if you alloy magnesium with _calcium_, you can produce an alloy
>>>>>>> that
>>>>>>> will not catch fire.
>>>>>>> Surely it would also be possible to make Titanum alloys that do not
>>>>>>> pose
>>>>>>> a fire hazard?
>>>>>>
>>>>>> (Hal Heydt)
>>>>>> Possibly...  I don't know if anyone has tried and what effect
>>>>>> alloying the Titanium has on its other properties.  Magnesium is
>>>>>> fairly easy to ignite so there is a real incentive--if you want
>>>>>> to use it at all--to find safer alloys.  Titanium is hard to
>>>>>> ignite, though if you manage to do it, it's all but impossible to
>>>>>> put out.
>>>>>
>>>>> There are not very many substances that can burn in an atmosphere of
>>>>> pure nitrogen.
>>>>
>>>> How about five pounds of liquid plutonium in a bucket ?
>>>>
>>> I don't think "burning" is the appropriate word to describe what that does.
>>
>> I thought critical mass for plutonium was about 11-12 lbs but no
>> question sub-critical amounts could generate far more than the
>> "normal" amount of radiation and depending on the amount could easily
>> be lethal even if not explosively so.
>
> (Hal Heydt)
> To the the best of my knowledge, it isn't a matter of critical mass
> with Pu-239, so much as critical density. That's why a "gun"
> type bomb (fire a core into a donut) works for U-235, but not
> Pu-239. For Pu-239 you have the enormously more difficult task
> of creating a spherical compression wave front to slam the pieces
> together hard enough to get the density up to the point that you
> get a--briefly--sustained fission reaction. It takes precisely
> shaped explosive lenses with microsecond detonation timing.
> Tough to do with the equipment available in 1945.

Critical mass is real bad for the guy holding the bucket, just ask the
Japanese guy who died a few days later after unloading the breeder
reactor in Japan. But the bucket was mostly uranium, not plutonium. I
am fairly sure that it did not matter to him.

Lynn

On Wednesday, October 12, 2022 at 5:56:53 PM UTC+1, Dorothy J Heydt wrote:
> In article <qs1dkhl5r1irirnar...@4ax.com>,
> The Horny Goat <lcr...@home.ca> wrote:
> >On Tue, 11 Oct 2022 04:13:59 -0700, Dimensional Traveler
> ><dtr...@sonic.net> wrote:
> >
> >>On 10/10/2022 9:47 PM, Lynn McGuire wrote:
> >>> On 10/10/2022 11:44 PM, Robert Woodward wrote:
> >>>> In article <rJKIn...@kithrup.com>,
> >>>> djh...@kithrup.com (Dorothy J Heydt) wrote:
> >>>>
> >>>>> In article <21b43580-c001-4c26...@googlegroups.com>,
> >>>>> Quadibloc <jsa...@ecn.ab.ca> wrote:
> >>>>>> On Monday, October 10, 2022 at 4:06:52 PM UTC-6, Dorothy J Heydt wrote:
> >>>>>>
> >>>>>>> So long as they don't start using Titanium structural members.
> >>>>>>> High current DC arc is one of the few ways you can light Titanium
> >>>>>>> on fire and if you think putting out Lithium battery fires is
> >>>>>>> hard...
> >>>>>>
> >>>>>> Magnesium, of course, catches fire quite easily. That's why it was
> >>>>>> used in flash bulbs.
> >>>>>> But when it is used to make light-weight metal items, it is usually
> >>>>>> alloyed with aluminum. This considerably reduces its tendency to
> >>>>>> catch fire.
> >>>>>> But it doesn't eleminate it completely, as was discovered when
> >>>>>> magnesium
> >>>>>> was first used to make racing cars. Shortly after, though, it was
> >>>>>> discovered
> >>>>>> that if you alloy magnesium with _calcium_, you can produce an alloy
> >>>>>> that
> >>>>>> will not catch fire.
> >>>>>> Surely it would also be possible to make Titanum alloys that do not
> >>>>>> pose
> >>>>>> a fire hazard?
> >>>>>
> >>>>> (Hal Heydt)
> >>>>> Possibly... I don't know if anyone has tried and what effect
> >>>>> alloying the Titanium has on its other properties. Magnesium is
> >>>>> fairly easy to ignite so there is a real incentive--if you want
> >>>>> to use it at all--to find safer alloys. Titanium is hard to
> >>>>> ignite, though if you manage to do it, it's all but impossible to
> >>>>> put out.
> >>>>
> >>>> There are not very many substances that can burn in an atmosphere of
> >>>> pure nitrogen.
> >>>
> >>> How about five pounds of liquid plutonium in a bucket ?
> >>>
> >>I don't think "burning" is the appropriate word to describe what that does.
> >
> >I thought critical mass for plutonium was about 11-12 lbs but no
> >question sub-critical amounts could generate far more than the
> >"normal" amount of radiation and depending on the amount could easily
> >be lethal even if not explosively so.
> (Hal Heydt)
> To the the best of my knowledge, it isn't a matter of critical mass
> with Pu-239, so much as critical density. That's why a "gun"
> type bomb (fire a core into a donut) works for U-235, but not
> Pu-239. For Pu-239 you have the enormously more difficult task
> of creating a spherical compression wave front to slam the pieces
> together hard enough to get the density up to the point that you
> get a--briefly--sustained fission reaction. It takes precisely
> shaped explosive lenses with microsecond detonation timing.
> Tough to do with the equipment available in 1945.

Difficult but done - Fat Man (Nagaski) was an implosion type plutonium bomb.. I think I heard claims that work on shaped charges for e.g. anti-tank weapons (also in their infancy) provided some background information. According to https://www.atomicarchive.com/science/fission/fat-man.html the problem with the gun type design using the plutonium available was not reluctance to detonate but a premature fizzle caused by impurities of Plutonium-240 going off too early.

Based on almost zero knowledge, I would expect a large enough mass to sustain an explosive chain reaction almost regardless of density: your aim is that each neutron produces, on average, more than one child neutron, by colliding with a fissile nucleus. If the core is large enough, almost every expelled neutron will find a nucleus to trigger before it exits, almost regardless of density, until you have something like a large cloud of vapour where there is a chance for the neutron to lose energy and generally lose interest before it finds a nucleus to trigger.

On 10/12/2022 1:28 PM, Lynn McGuire wrote:
> On 10/12/2022 11:45 AM, Dorothy J Heydt wrote:
>> In article <qs1dkhl5r1irirnarksk5lbsjuq8ptvtju@4ax.com>,
>> The Horny Goat  <lcraver@home.ca> wrote:
>>> On Tue, 11 Oct 2022 04:13:59 -0700, Dimensional Traveler
>>> <dtravel@sonic.net> wrote:
>>>
>>>> On 10/10/2022 9:47 PM, Lynn McGuire wrote:
>>>>> On 10/10/2022 11:44 PM, Robert Woodward wrote:
>>>>>> In article <rJKInL.96p@kithrup.com>,
>>>>>>    djheydt@kithrup.com (Dorothy J Heydt) wrote:
>>>>>>
>>>>>>> In article <21b43580-c001-4c26-87d3-1cc2c1ad0ee3n@googlegroups.com>,
>>>>>>> Quadibloc  <jsavard@ecn.ab.ca> wrote:
>>>>>>>> On Monday, October 10, 2022 at 4:06:52 PM UTC-6, Dorothy J Heydt
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> So long as they don't start using Titanium structural members.
>>>>>>>>> High current DC arc is one of the few ways you can light Titanium
>>>>>>>>> on fire and if you think putting out Lithium battery fires is
>>>>>>>>> hard...
>>>>>>>>
>>>>>>>> Magnesium, of course, catches fire quite easily. That's why it was
>>>>>>>> used in flash bulbs.
>>>>>>>> But when it is used to make light-weight metal items, it is usually
>>>>>>>> alloyed with aluminum. This considerably reduces its tendency to
>>>>>>>> catch fire.
>>>>>>>> But it doesn't eleminate it completely, as was discovered when
>>>>>>>> magnesium
>>>>>>>> was first used to make racing cars. Shortly after, though, it was
>>>>>>>> discovered
>>>>>>>> that if you alloy magnesium with _calcium_, you can produce an
>>>>>>>> alloy
>>>>>>>> that
>>>>>>>> will not catch fire.
>>>>>>>> Surely it would also be possible to make Titanum alloys that do not
>>>>>>>> pose
>>>>>>>> a fire hazard?
>>>>>>>
>>>>>>> (Hal Heydt)
>>>>>>> Possibly...  I don't know if anyone has tried and what effect
>>>>>>> alloying the Titanium has on its other properties.  Magnesium is
>>>>>>> fairly easy to ignite so there is a real incentive--if you want
>>>>>>> to use it at all--to find safer alloys.  Titanium is hard to
>>>>>>> ignite, though if you manage to do it, it's all but impossible to
>>>>>>> put out.
>>>>>>
>>>>>> There are not very many substances that can burn in an atmosphere of
>>>>>> pure nitrogen.
>>>>>
>>>>> How about five pounds of liquid plutonium in a bucket ?
>>>>>
>>>> I don't think "burning" is the appropriate word to describe what
>>>> that does.
>>>
>>> I thought critical mass for plutonium was about 11-12 lbs but no
>>> question sub-critical amounts could generate far more than the
>>> "normal" amount of radiation and depending on the amount could easily
>>> be lethal even if not explosively so.
>>
>> (Hal Heydt)
>> To the the best of my knowledge, it isn't a matter of critical mass
>> with Pu-239, so much as critical density.  That's why a "gun"
>> type bomb (fire a core into a donut) works for U-235, but not
>> Pu-239.  For Pu-239 you have the enormously more difficult task
>> of creating a spherical compression wave front to slam the pieces
>> together hard enough to get the density up to the point that you
>> get a--briefly--sustained fission reaction.  It takes precisely
>> shaped explosive lenses with microsecond detonation timing.
>> Tough to do with the equipment available in 1945.
>
> Critical mass is real bad for the guy holding the bucket, just ask the
> Japanese guy who died a few days later after unloading the breeder
> reactor in Japan.  But the bucket was mostly uranium, not plutonium.  I
> am fairly sure that it did not matter to him.
>
> Lynn

https://en.wikipedia.org/wiki/Tokaimura_nuclear_accidents#1999_accident

Lynn

Andrew McDowell <mcdowell_ag@sky.com> writes:
>On Wednesday, October 12, 2022 at 5:56:53 PM UTC+1, Dorothy J Heydt wrote:
>> In article <qs1dkhl5r1irirnar...@4ax.com>,

>> (Hal Heydt)=20
>> To the the best of my knowledge, it isn't a matter of critical mass=20
>> with Pu-239, so much as critical density. That's why a "gun"=20
>> type bomb (fire a core into a donut) works for U-235, but not=20
>> Pu-239. For Pu-239 you have the enormously more difficult task=20
>> of creating a spherical compression wave front to slam the pieces=20
>> together hard enough to get the density up to the point that you=20
>> get a--briefly--sustained fission reaction. It takes precisely=20
>> shaped explosive lenses with microsecond detonation timing.=20
>> Tough to do with the equipment available in 1945.
>
>Difficult but done - Fat Man (Nagaski) was an implosion type plutonium bomb=
>. I think I heard claims that work on shaped charges for e.g. anti-tank wea=
>pons (also in their infancy) provided some background information.

Picture a volleyball. Note that mix of hexagons and pentagons. Now
construct an outer shell using similarly shaped molded fast explosives,
each with an ignitor and ignition wire. All wires must be _exactly_
the same length.

>Based on almost zero knowledge, I would expect a large enough mass to susta=
>in an explosive chain reaction almost regardless of density: your aim is th=
>at each neutron produces, on average, more than one child neutron, by colli=
>ding with a fissile nucleus. If the core is large enough, almost every expe=
>lled neutron will find a nucleus to trigger before it exits, almost regardl=
>ess of density, until you have something like a large cloud of vapour where=
> there is a chance for the neutron to lose energy and generally lose intere=
>st before it finds a nucleus to trigger.

You need to be careful that you don't blow apart the reactive materials
before the chain reaction reaches the point of no return.

On Wednesday, October 12, 2022 at 8:40:58 AM UTC-5, Quadibloc wrote:
> On Tuesday, October 11, 2022 at 8:05:46 AM UTC-6, peterw...@hotmail.com wrote:
> > On Monday, October 10, 2022 at 11:44:28 PM UTC-5, Robert Woodward wrote:
>
> > > There are not very many substances that can burn in an atmosphere of
> > > pure nitrogen.
>
> > Titanium will burn in nitrogen, carbon dioxide, or water. To smother burning
> > titanium use argon or helium.
> Aside from helium being lighter than air and all that, wouldn't neon also work,
> being less reactive than argon, but more reactive than helium? And are you
> claiming that titanium will burn in an atmosphere of pure krypton or xenon?

No, any of the inert gases would work to smother burning titanium. Argon and
helium are the easiest to obtain. both being available at welding supply dealers.

Peter Wezeman
anti-social Darwinist

On Wed, 12 Oct 2022 13:28:30 -0500, Lynn McGuire
<lynnmcguire5@gmail.com> wrote:

>Critical mass is real bad for the guy holding the bucket, just ask the
>Japanese guy who died a few days later after unloading the breeder
>reactor in Japan. But the bucket was mostly uranium, not plutonium. I
>am fairly sure that it did not matter to him.
>
Hmmm must not have been the natural 1/140 U-235 / U-238 breakdown then
since natural uranium is 99.2% U-238 / .8% U-235 and that wouldn't
kill you other than if a large block of it fell on your.

Concentrated U-235 is MUCH more radioactive and could be harmful
though usually when they say "enriched uranium" they mean with a 3-5%
U-235 content.

90+% of the US nuclear arsenal is however made from plutonium which is
made from enriched uranium. "Depleted uranium" is natural uranium with
the U-235 component taken out and is a favored metal for armor
piercing shells though one used infrequently today due to its
environmental effects. (It's said to penetrate 20% better than
tungsten carbide against tank armor plating)

On 10/14/2022 3:41 PM, The Horny Goat wrote:
> On Wed, 12 Oct 2022 13:28:30 -0500, Lynn McGuire
> <lynnmcguire5@gmail.com> wrote:
>
>> Critical mass is real bad for the guy holding the bucket, just ask the
>> Japanese guy who died a few days later after unloading the breeder
>> reactor in Japan. But the bucket was mostly uranium, not plutonium. I
>> am fairly sure that it did not matter to him.
>>
> Hmmm must not have been the natural 1/140 U-235 / U-238 breakdown then
> since natural uranium is 99.2% U-238 / .8% U-235 and that wouldn't
> kill you other than if a large block of it fell on your.
>
> Concentrated U-235 is MUCH more radioactive and could be harmful
> though usually when they say "enriched uranium" they mean with a 3-5%
> U-235 content.
>
> 90+% of the US nuclear arsenal is however made from plutonium which is
> made from enriched uranium. "Depleted uranium" is natural uranium with
> the U-235 component taken out and is a favored metal for armor
> piercing shells though one used infrequently today due to its
> environmental effects. (It's said to penetrate 20% better than
> tungsten carbide against tank armor plating)

The uranium in the Japanese breeder reactor was 18% enriched. Good
stuff. Oops.
https://en.wikipedia.org/wiki/Tokaimura_nuclear_accidents#1999_accident

Lynn
Lynn

In article <03ijkh14t253b28nm4vq62ihehea8u537k@4ax.com>,
The Horny Goat <lcraver@home.ca> wrote:
>90+% of the US nuclear arsenal is however made from plutonium which is
>made from enriched uranium. "Depleted uranium" is natural uranium with
>the U-235 component taken out and is a favored metal for armor
>piercing shells though one used infrequently today due to its
>environmental effects. (It's said to penetrate 20% better than
>tungsten carbide against tank armor plating)

(Hal Heydt)
Depleted Urainum is also pyrotic, which is to say that when you
slam it through a steel plate it ges hot enough to start burning.
That means that you have burning chunks of Uranium--at around
3000'C, bouncing around inside your tank, tending to cause other
things to start burning...like ammunition. So...when it all gets
done, not much left of the crew or the tank.

On Friday, October 14, 2022 at 6:41:56 PM UTC-4, Dorothy J Heydt wrote:
> In article <03ijkh14t253b28nm...@4ax.com>,
> The Horny Goat <lcr...@home.ca> wrote:
> >90+% of the US nuclear arsenal is however made from plutonium which is
> >made from enriched uranium. "Depleted uranium" is natural uranium with
> >the U-235 component taken out and is a favored metal for armor
> >piercing shells though one used infrequently today due to its
> >environmental effects. (It's said to penetrate 20% better than
> >tungsten carbide against tank armor plating)
> (Hal Heydt)
> Depleted Urainum is also pyrotic, which is to say that when you
> slam it through a steel plate it ges hot enough to start burning.
> That means that you have burning chunks of Uranium--at around
> 3000'C, bouncing around inside your tank, tending to cause other
> things to start burning...like ammunition. So...when it all gets
> done, not much left of the crew or the tank.

Not only that, when used as an armor penetrator, the tip wears in
such a way that it remains sharp. Add in the pyrophoric property
of self ignition (similar to a lighter flint), and it's not something
to stand in front of.

W, Pu and U all have densities in the 19-20 range. Lead is only 11. I once
picked up a piece of depleted Uranium about the size of a small juice can.
[Yes, there was safely equipment involved.] it was far, far heavier than I
expected. It's sometimes used in applications like counterweights for
airplane flaps, or in sailboat keels.

Pt

On Friday, October 14, 2022 at 10:01:38 PM UTC-5, pete...@gmail.com wrote:
> On Friday, October 14, 2022 at 6:41:56 PM UTC-4, Dorothy J Heydt wrote:
> > In article <03ijkh14t253b28nm...@4ax.com>,
> > The Horny Goat <lcr...@home.ca> wrote:
> > >90+% of the US nuclear arsenal is however made from plutonium which is
> > >made from enriched uranium. "Depleted uranium" is natural uranium with
> > >the U-235 component taken out and is a favored metal for armor
> > >piercing shells though one used infrequently today due to its
> > >environmental effects. (It's said to penetrate 20% better than
> > >tungsten carbide against tank armor plating)
> > (Hal Heydt)
> > Depleted Urainum is also pyrotic, which is to say that when you
> > slam it through a steel plate it ges hot enough to start burning.
> > That means that you have burning chunks of Uranium--at around
> > 3000'C, bouncing around inside your tank, tending to cause other
> > things to start burning...like ammunition. So...when it all gets
> > done, not much left of the crew or the tank.
> Not only that, when used as an armor penetrator, the tip wears in
> such a way that it remains sharp. Add in the pyrophoric property
> of self ignition (similar to a lighter flint), and it's not something
> to stand in front of.
>
> W, Pu and U all have densities in the 19-20 range. Lead is only 11. I once
> picked up a piece of depleted Uranium about the size of a small juice can.
> [Yes, there was safely equipment involved.] it was far, far heavier than I
> expected. It's sometimes used in applications like counterweights for
> airplane flaps, or in sailboat keels.
>
Depleted uranium is produced in fairly large quantities in the course of
enriching uranium and so is the least expensive material of that density
available; I recall that is used for the elevator counterweights in the
Lockheed C-5 airlifter. I think tungsten is next most expensive. To control
costs in some classes of yacht racing materials denser that lead were
forbidden. Density is useful both in armor piercing projectiles and in armor.
Depleted uranium is used in the Chobham armor array in the current model
of the United States M-1 Abrams tank.

Peter Wezeman
anti-social Darwinist

In article <43860a5d-6a78-464c-b4e4-8b7868620997n@googlegroups.com>,
pete...@gmail.com <petertrei@gmail.com> wrote:
>On Friday, October 14, 2022 at 6:41:56 PM UTC-4, Dorothy J Heydt wrote:
>> In article <03ijkh14t253b28nm...@4ax.com>,
>> The Horny Goat <lcr...@home.ca> wrote:
>> >90+% of the US nuclear arsenal is however made from plutonium which is
>> >made from enriched uranium. "Depleted uranium" is natural uranium with
>> >the U-235 component taken out and is a favored metal for armor
>> >piercing shells though one used infrequently today due to its
>> >environmental effects. (It's said to penetrate 20% better than
>> >tungsten carbide against tank armor plating)
>> (Hal Heydt)
>> Depleted Urainum is also pyrotic, which is to say that when you
>> slam it through a steel plate it ges hot enough to start burning.
>> That means that you have burning chunks of Uranium--at around
>> 3000'C, bouncing around inside your tank, tending to cause other
>> things to start burning...like ammunition. So...when it all gets
>> done, not much left of the crew or the tank.
>
>Not only that, when used as an armor penetrator, the tip wears in
>such a way that it remains sharp. Add in the pyrophoric property
>of self ignition (similar to a lighter flint), and it's not something
>to stand in front of.
>
>W, Pu and U all have densities in the 19-20 range. Lead is only 11. I once
>picked up a piece of depleted Uranium about the size of a small juice can.
>[Yes, there was safely equipment involved.] it was far, far heavier than I
>expected. It's sometimes used in applications like counterweights for
>airplane flaps, or in sailboat keels.

(Hal Heydt)
Ever watch someone (or do it yourself) pick up a bottle of
Mercury? Same thing. Feels like it's nailed in place.

At least for liquids, ones expectation--and thus the "set" for
muscles--is that they have a specific gravity of about one. If
something in a bottle is markedly different, it feels much
farther off what you expect than it actually is.

On Friday, October 14, 2022 at 11:56:56 PM UTC-4, Dorothy J Heydt wrote:
> In article <43860a5d-6a78-464c...@googlegroups.com>,
> pete...@gmail.com <pete...@gmail.com> wrote:
> >On Friday, October 14, 2022 at 6:41:56 PM UTC-4, Dorothy J Heydt wrote:
> >> In article <03ijkh14t253b28nm...@4ax.com>,
> >> The Horny Goat <lcr...@home.ca> wrote:
> >> >90+% of the US nuclear arsenal is however made from plutonium which is
> >> >made from enriched uranium. "Depleted uranium" is natural uranium with
> >> >the U-235 component taken out and is a favored metal for armor
> >> >piercing shells though one used infrequently today due to its
> >> >environmental effects. (It's said to penetrate 20% better than
> >> >tungsten carbide against tank armor plating)
> >> (Hal Heydt)
> >> Depleted Urainum is also pyrotic, which is to say that when you
> >> slam it through a steel plate it ges hot enough to start burning.
> >> That means that you have burning chunks of Uranium--at around
> >> 3000'C, bouncing around inside your tank, tending to cause other
> >> things to start burning...like ammunition. So...when it all gets
> >> done, not much left of the crew or the tank.
> >
> >Not only that, when used as an armor penetrator, the tip wears in
> >such a way that it remains sharp. Add in the pyrophoric property
> >of self ignition (similar to a lighter flint), and it's not something
> >to stand in front of.
> >
> >W, Pu and U all have densities in the 19-20 range. Lead is only 11. I once
> >picked up a piece of depleted Uranium about the size of a small juice can.
> >[Yes, there was safely equipment involved.] it was far, far heavier than I
> >expected. It's sometimes used in applications like counterweights for
> >airplane flaps, or in sailboat keels.
> (Hal Heydt)
> Ever watch someone (or do it yourself) pick up a bottle of
> Mercury? Same thing. Feels like it's nailed in place.
>
> At least for liquids, ones expectation--and thus the "set" for
> muscles--is that they have a specific gravity of about one. If
> something in a bottle is markedly different, it feels much
> farther off what you expect than it actually is.

True. Mercury's density is about 13.5.

Pt

In article <43860a5d-6a78-464c-b4e4-8b7868620997n@googlegroups.com>,
"pete...@gmail.com" <petertrei@gmail.com> wrote:

> On Friday, October 14, 2022 at 6:41:56 PM UTC-4, Dorothy J Heydt wrote:
> > In article <03ijkh14t253b28nm...@4ax.com>,
> > The Horny Goat <lcr...@home.ca> wrote:
> > >90+% of the US nuclear arsenal is however made from plutonium which is
> > >made from enriched uranium. "Depleted uranium" is natural uranium with
> > >the U-235 component taken out and is a favored metal for armor
> > >piercing shells though one used infrequently today due to its
> > >environmental effects. (It's said to penetrate 20% better than
> > >tungsten carbide against tank armor plating)
> > (Hal Heydt)
> > Depleted Urainum is also pyrotic, which is to say that when you
> > slam it through a steel plate it ges hot enough to start burning.
> > That means that you have burning chunks of Uranium--at around
> > 3000'C, bouncing around inside your tank, tending to cause other
> > things to start burning...like ammunition. So...when it all gets
> > done, not much left of the crew or the tank.
>
> Not only that, when used as an armor penetrator, the tip wears in
> such a way that it remains sharp. Add in the pyrophoric property
> of self ignition (similar to a lighter flint), and it's not something
> to stand in front of.
>
> W, Pu and U all have densities in the 19-20 range. Lead is only 11. I once
> picked up a piece of depleted Uranium about the size of a small juice can.
> [Yes, there was safely equipment involved.] it was far, far heavier than I
> expected. It's sometimes used in applications like counterweights for
> airplane flaps, or in sailboat keels.

Depleted uranium is used for counter weights for airplane ailerons (and,
IIRC, elevators and elevator tabs), not flaps (not needed for flaps
since they are powered surfaces).

--
"We have advanced to new and surprising levels of bafflement."
Imperial Auditor Miles Vorkosigan describes progress in _Komarr_.
—-----------------------------------------------------
Robert Woodward robertaw@drizzle.com

Among the things peterwezeman@hotmail.com wrote:

> To control
> costs in some classes of yacht racing materials denser that lead were
> forbidden.

It's been soooo long since I heard about the America's Cup.

--
-Jack

On Saturday, October 15, 2022 at 10:10:02 AM UTC-4, jack....@gmail.com wrote:
> Among the things peterw...@hotmail.com wrote:
>
> > To control
> > costs in some classes of yacht racing materials denser that lead were
> > forbidden.
> It's been soooo long since I heard about the America's Cup.

The boats and speeds have changed a lot. Since 2013 they are now all hydrofoils flying
along at 50 knots, about 60 mph. Quite spectacular.

https://www.youtube.com/watch?v=OQsXDdGxk3U

For more than 100 years, the US held the cup, and made the rules. One rule was
that boat had to sail to the race site, Newport RI, on its own hull (usually towed).
This gave US a huge home team advantage, since non US boats had to be sturdy
enough to cross open ocean.

Pt