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.
"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."
Balti Sea Ice service shows current ice conditions to be less than normal.
Balti Sea Ice service shows current ice conditions to be less than normal.
Come on Richard, no need to confuse and agitate the deniers with facts! :)
There is a better map at
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
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.
Paul Keinanen wrote: : 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
Yeah, like the "fact" that the Himalaya range will be ice-free in about
25 years :-)-- SCNR, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
The Baltic situation being discussed is measured, not predicted.
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.
The good ones do. Example from one of my recent hi-rel designs, down to
-55C:
Sometimes you have to ask for such data. If a mfg balks at such requests that would be a red flag.
The ones above weren't very expensive, IIRC around two bucks.
Look for categories such as "space and harsh environments", like here:
They also have resistor-set oscillators if you can use those:
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 :-)
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
Paul Keinanen wrote: : 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
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
And from a hardware testing POV - what do others do to test sub zero (Celcius) without a proper humidity controlled envirochamber? In the past I had fun testing some gear down to about -10C with condensation on the board creating havoc. In the end we placed the boards in a sealed box with some dessicant.
Spehro Pefhany wrote: : 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
You can get higher voltage JFETs. Not for pennies, but also not outrageously expensive.
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
Baltic
So much fun, your own link undercuts your argument.
Hmmm. Been studying up a bit recently. Logic fets may be doubly=20 degenerately doped.
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
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
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.
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
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