Cruise ship stuck in ice

[amdx]

That damn global warming!

Several ships, including one small cruise liner, were stuck in ice....
More than 30 ships were plagued by the problem and stranded at sea
until the ice was cut away early today, March 5, 2010.

http://www.examiner.com/x-20221-Lon...y2010m3d5-cruise-ships-stuck-in-ice-are-freed

"It has been a lot colder than normal in the southern parts of the Baltic
Sea.
But in the north, all is normal, with normal levels of ice."

 

[Paul Keinanen]

Balti Sea Ice service shows current ice conditions to be less than
normal.

http://www.fmi.fi/weather/index_9.html

There is a better map at
http://www.itameriportaali.fi/html/icef/icemap_c.pdf

The location at which the ships were stuck are North-East of
Stockholm, East of Norrtälje.

The water in the Baltic sea was warmer than normal at the end of the
last year, while temperatures on land has been below freezing for 2-3
months continuously (which is quite unusual).

The ice situation is similar to the average situation last century,
but in the last decade, some ice breakers have been sitting at the
docks all year (so no cebreaker crew strikes recenly , but this
winter they are all out doing some useful work.

Cruise liners between Finland, Sweden and Estonia are designed to
operate without icebreaker assistance during the winter (sufficient
engine power), while ordinary merchant ships usually require
icebreaker assistance in the winter.

The current situation occurred because the wind was blowing towards
the Stockholm archipelago, packing ice into the narrow channel. The
cruise liners did not have enough power to handle this pack ice (3 m
above and 10 m below the sea level), neither did the small harbor
icebreakers, so they really had to call in the big Baltic sea
icebreakers.

A similar situation occurred a few weeks ago, when an underpowered
cruise liner between Finland and Estonia was stuck for several hours
when the wind was blowing ice from the South against the coast of
Finland and the liner was stuck for several hours. A more powerful
liner did cut it out from the ice, but this did not reach
international headlines.

During the Little Ice Age, tho whole Baltic Sea could be frozen
http://en.wikipedia.org/wiki/March_across_the_Belts and a full army
could march from Sweden to Denmark in 1658.

The current situation in Finland (continuous freezing temperatures for
2-3 months and nearly 1 m of snow) might be a shock for youngsters,
but the oldsters have seen worse.

Apparently due to the warmingist propaganda, the railroad network in
Finland is stuck, when there are cold temperatures or some snow and
trains are hours late, while in the Saint Petersburg region in Russia
(just 200-400 km East from here) such climate conditions do not cause
problem for the traffic.

In previous decades during the winter, systems operated as least as
good in Finland as in Russia.

 

[Okkim Atnarivik]

: The current situation in Finland (continuous freezing temperatures for
: 2-3 months and nearly 1 m of snow) might be a shock for youngsters,
: but the oldsters have seen worse.

It's great to have a good old-fashioned winter. When I was a student
in 80's we flew hang-gliders in several winters by car tow launching
them on the frozen sea in front of Helsinki. That has not been possible
very often ever since.

: Apparently due to the warmingist propaganda, the railroad network in
: Finland is stuck, when there are cold temperatures or some snow and
: trains are hours late, while in the Saint Petersburg region in Russia
: (just 200-400 km East from here) such climate conditions do not cause
: problem for the traffic.

I agree that probably expectations of warmer and warmer winters has
kept the VR railroad company from investing in snow-tolerant equipment.
Now they are taken by surprise by this downswing in temperature. Still,
I think the cold winter here is just an anecdote - not saying much
about the global average temperature, and even less about what the
long-term trend actually is. The artficially warm recent winters (in
particular 07-08) have felt really creepy.

Regards,
Mikko

 

[Joerg]

Royston Vasey wrote:

[...]

Come on Richard, no need to confuse and agitate the deniers with facts!

Yeah, like the "fact" that the Himalaya range will be ice-free in about
25 years

 

[Paul Keinanen]

Paul Keinanen <[email protected]> wrote:

: Apparently due to the warmingist propaganda, the railroad network in
: Finland is stuck, when there are cold temperatures or some snow and
: trains are hours late, while in the Saint Petersburg region in Russia
: (just 200-400 km East from here) such climate conditions do not cause
: problem for the traffic.

I agree that probably expectations of warmer and warmer winters has
kept the VR railroad company from investing in snow-tolerant equipment.
Now they are taken by surprise by this downswing in temperature. Still,
I think the cold winter here is just an anecdote - not saying much
about the global average temperature, and even less about what the
long-term trend actually is. The artficially warm recent winters (in
particular 07-08) have felt really creepy.

Regards,
Mikko

In order to keep this discussion on topic, why is it so hard to get
component specifications from semiconductor manufacturers for
temperatures below 0 C ?

I mostly work for a company that ships products all over the world
(including Siberia) and we have to test the equipment shipped at low
temperatures in order to avoid using military priced components for
ordinary industrial applications.

In practice, most problems at low temperature systems are associated
with getting oscillators to oscillate at low temperatures.

 

[Joerg]

In order to keep this discussion on topic, why is it so hard to get
component specifications from semiconductor manufacturers for
temperatures below 0 C ?

The good ones do. Example from one of my recent hi-rel designs, down to
-55C:

http://cds.linear.com/docs/Datasheet/6700123ff.pdf

Sometimes you have to ask for such data. If a mfg balks at such requests
that would be a red flag.

I mostly work for a company that ships products all over the world
(including Siberia) and we have to test the equipment shipped at low
temperatures in order to avoid using military priced components for
ordinary industrial applications.

The ones above weren't very expensive, IIRC around two bucks.

In practice, most problems at low temperature systems are associated
with getting oscillators to oscillate at low temperatures.

Look for categories such as "space and harsh environments", like here:
http://www.linear.com/pc/viewCategory.jsp?navId=H0,C1,C1778,C1503

They also have resistor-set oscillators if you can use those:
http://cds.linear.com/docs/Information Card/LTCMP.pdf

What kind of problems do you have to get oscillators started? Russian
truckers sometimes light a little wood fire under the engine to warm it
a bit but I guess that's not an option in your case

 

[Okkim Atnarivik]

: In order to keep this discussion on topic, why is it so hard to get
: component specifications from semiconductor manufacturers for
: temperatures below 0 C ?

Actually, more and more modern CMOS semiconductors seem to work even
at 4.2K . More so than, say, 15 years ago. My wild guess is that
linewidth reduction combined with higher switching speed requirements
have driven the manufacturers to use heavier doping levels, attempting
to get higher mobility. A side effect is that the carriers no longer
freeze out.

Regards,
Mikko

 

[Spehro Pefhany]

: In order to keep this discussion on topic, why is it so hard to get
: component specifications from semiconductor manufacturers for
: temperatures below 0 C ?

Actually, more and more modern CMOS semiconductors seem to work even
at 4.2K . More so than, say, 15 years ago. My wild guess is that
linewidth reduction combined with higher switching speed requirements
have driven the manufacturers to use heavier doping levels, attempting
to get higher mobility. A side effect is that the carriers no longer
freeze out.

Regards,
Mikko

I thought it was primarily bipolar that had problems with 4K
(including such weirdities as Si diodes oscillating. Do you have/would
you be willing to share a list of parts that have been found to work
at liquid He temperatures?


Best regards,
Spehro Pefhany

 

[Okkim Atnarivik]

: I thought it was primarily bipolar that had problems with 4K
: (including such weirdities as Si diodes oscillating. Do you have/would

Si bipolar transistors, JFETs and depletion-mode MOSFETs indeed
tend to freeze out. Enhancement-mode MOSFETs often work, but even them
not always. One possibility is that the ohmic contacts freeze even when
the channel itself might continue functioning. Maybe another factor
is that the modern devices are designed for low supply voltages, so
that there is no longer room to use other than enhancement-mode
FETs within the voltage budget. I don't know for sure.

Regards,
Mikko

 

[Joerg]

: I thought it was primarily bipolar that had problems with 4K
: (including such weirdities as Si diodes oscillating. Do you have/would

Si bipolar transistors, JFETs and depletion-mode MOSFETs indeed
tend to freeze out. Enhancement-mode MOSFETs often work, but even them
not always. One possibility is that the ohmic contacts freeze even when
the channel itself might continue functioning. Maybe another factor
is that the modern devices are designed for low supply voltages, so
that there is no longer room to use other than enhancement-mode
FETs within the voltage budget. I don't know for sure.

You can get higher voltage JFETs. Not for pennies, but also not
outrageously expensive.

 

[JosephKK]

Balti Sea Ice service shows current ice conditions to be less than
normal.

http://www.fmi.fi/weather/index_9.html


Come on Richard, no need to confuse and agitate the deniers with facts!

So much fun, your own link undercuts your argument.

 

[JosephKK]

: In order to keep this discussion on topic, why is it so hard to get
: component specifications from semiconductor manufacturers for
: temperatures below 0 C ?

Actually, more and more modern CMOS semiconductors seem to work even
at 4.2K . More so than, say, 15 years ago. My wild guess is that
linewidth reduction combined with higher switching speed requirements
have driven the manufacturers to use heavier doping levels, attempting
to get higher mobility. A side effect is that the carriers no longer
freeze out.

Regards,
Mikko

Hmmm. Been studying up a bit recently. Logic fets may be doubly
degenerately doped.

 

[JosephKK]

I thought it was primarily bipolar that had problems with 4K
(including such weirdities as Si diodes oscillating. Do you have/would
you be willing to share a list of parts that have been found to work
at liquid He temperatures?


Best regards,
Spehro Pefhany

I have seen many reports of PCs being super-hotrodded in LN2.

 

[Spehro Pefhany]

I have seen many reports of PCs being super-hotrodded in LN2.

Sure, but LN2 is a balmy 77K .. unfortunately a lot more tends to go
wrong in the next 73K down..


Best regards,
Spehro Pefhany

 

[Paul Keinanen]

Look for categories such as "space and harsh environments", like here:
http://www.linear.com/pc/viewCategory.jsp?navId=H0,C1,C1778,C1503

They also have resistor-set oscillators if you can use those:
http://cds.linear.com/docs/Information Card/LTCMP.pdf

What kind of problems do you have to get oscillators started? Russian
truckers sometimes light a little wood fire under the engine to warm it
a bit but I guess that's not an option in your case

An oscillator is simply an amplifier with a frequency selective
feedback path that satisfies the Barkhausen criterion (gain larger
than the feedback path loss).

When an amplifier is powered up with a frequency selective feedback
network, first the wide band thermal noise (about -174 dBm/Hz at room
temperatures) is amplified and the noise after frequency shaping in
the LC network is feed back to the input of the amplifier. After a few
times though the amplifier, the broadband noise has been reduced to a
narrow band single frequency signal, when the amplifier is saturated
by noise.

For a proper startup, the oscillator must start in class A or AB,
while later on, it can drop to class C.

At very low temperatures, if the Barkhausen requirement is not
satisfied, if the gain drops too much at low temperatures, preventing
the oscillation.

 

[Joerg]

An oscillator is simply an amplifier with a frequency selective
feedback path that satisfies the Barkhausen criterion (gain larger
than the feedback path loss).

When an amplifier is powered up with a frequency selective feedback
network, first the wide band thermal noise (about -174 dBm/Hz at room
temperatures) is amplified and the noise after frequency shaping in
the LC network is feed back to the input of the amplifier. After a few
times though the amplifier, the broadband noise has been reduced to a
narrow band single frequency signal, when the amplifier is saturated
by noise.

For a proper startup, the oscillator must start in class A or AB,
while later on, it can drop to class C.

At very low temperatures, if the Barkhausen requirement is not
satisfied, if the gain drops too much at low temperatures, preventing
the oscillation.

This is not the only way to start an oscillator. Another method when
there isn't enough initial gain and/or noise is a kicker circuit. Can be
a bit tricky because often there must be additional circuitry that
detects a successful start and if necessary can initiate restart attempts.