Saturday, September 14, 2019
Friday, September 13, 2019
Polyethylene, radar, and submarine cables
.
22-9-21 How Xina’s Military Drills Could Choke Off Taiwan’s Internet | WSJ > .
Undersea Communication Cables - Mega > .
Undersea Communication Cables - Mega > .
Why 17 Million Telegrams Are Still Sent Every Year - Half > .
Communication, Surveillance - PrTe >> .
Communication, Surveillance - PrTe >> .
Undersea Cables, Pipelines - Naval Gazing >> .
Polyethylene, radar, and submarine cables
Communication infrastructure ..
"They had heated a mixture of ethylene and benzaldehyde to 170°C (338°F), using apparatus that could submit materials to a pressure of 1,900 atmospheres (1,925 bars). But the reactions were explosive and safety concerns prompted the now defunct ICI, which merged into Dutch-based Akzo Nobel, to halt the research.
In December that year, Williams and colleagues Michael Perrin and John Paton reinvestigated the experiments of Gibson and Fawcett using ethylene alone. Under similar experimental conditions - but with better equipment - they observed a pressure drop, and when the reaction finished there were 8.5g of white PE powder.
Williams, Perrin and Paton had been lucky. The vessel had leaked and, it was later confirmed, a trace of oxygen was present in the fresh ethylene that had been added to the reaction vessel to replace the leaked gas. The fresh ethylene contained, by chance, the right amount of oxygen to act as an initiator.
"For once it didn't explode - usually it did - and we thought something must be wrong. So we left it to cool overnight. And when I looked inside the metal container the next day, I found what looked like a lump of sugar. In fact, that 'sugar' was polythene."
Uses for early PE were limited, as the material was soft and had a low melting point. This was because under the high pressure polymerization process the ethylene molecules did not always add in a regular chain.
A member of ICI's dyestuffs division, Bernard Habgood, recognized that PE could supersede gutta-percha, a natural material, for insulation of submarine cables. This provided the impetus to proceed to commercial scale production. The first full-scale PE plant, with a 100 tonne/year capacity, went into production on September 1, 1939, the day Germany invaded Poland and war became unavoidable for Britain.
ICI's work on PE changed during the Second World War, when the material was used to insulate airborne radar equipment. During the development of radar in the early war years it had proved difficult to insulate the equipment to prevent power loss and thus preserve the strength of the signal. PE's electrical insulation properties enabled the British forces to reduce the weight of radar equipment and allowed them to place radars inside fighter planes. This provided an enormous technical advantage in long-distance warfare, most significantly in the Battle of the Atlantic against German submarines. The Germans were obliged to use a bulkier insulating material for their radar, which was less effective."
http://www.icis.com/resources/news/2008/05/12/9122447/polyethylene-discovered-by-accident-75-years-ago/
https://en.wikipedia.org/wiki/Polyethylene
http://www.polymer-search.com/inventionplastic.html
http://www.acs.org/content/acs/en/education/whatischemistry/landmarks/polypropylene.html
http://www.independent.co.uk/news/science/polythenes-story-the-accidental-birth-of-plastic-bags-800602.html .
Communication infrastructure ..
"They had heated a mixture of ethylene and benzaldehyde to 170°C (338°F), using apparatus that could submit materials to a pressure of 1,900 atmospheres (1,925 bars). But the reactions were explosive and safety concerns prompted the now defunct ICI, which merged into Dutch-based Akzo Nobel, to halt the research.
In December that year, Williams and colleagues Michael Perrin and John Paton reinvestigated the experiments of Gibson and Fawcett using ethylene alone. Under similar experimental conditions - but with better equipment - they observed a pressure drop, and when the reaction finished there were 8.5g of white PE powder.
Williams, Perrin and Paton had been lucky. The vessel had leaked and, it was later confirmed, a trace of oxygen was present in the fresh ethylene that had been added to the reaction vessel to replace the leaked gas. The fresh ethylene contained, by chance, the right amount of oxygen to act as an initiator.
"For once it didn't explode - usually it did - and we thought something must be wrong. So we left it to cool overnight. And when I looked inside the metal container the next day, I found what looked like a lump of sugar. In fact, that 'sugar' was polythene."
Uses for early PE were limited, as the material was soft and had a low melting point. This was because under the high pressure polymerization process the ethylene molecules did not always add in a regular chain.
A member of ICI's dyestuffs division, Bernard Habgood, recognized that PE could supersede gutta-percha, a natural material, for insulation of submarine cables. This provided the impetus to proceed to commercial scale production. The first full-scale PE plant, with a 100 tonne/year capacity, went into production on September 1, 1939, the day Germany invaded Poland and war became unavoidable for Britain.
ICI's work on PE changed during the Second World War, when the material was used to insulate airborne radar equipment. During the development of radar in the early war years it had proved difficult to insulate the equipment to prevent power loss and thus preserve the strength of the signal. PE's electrical insulation properties enabled the British forces to reduce the weight of radar equipment and allowed them to place radars inside fighter planes. This provided an enormous technical advantage in long-distance warfare, most significantly in the Battle of the Atlantic against German submarines. The Germans were obliged to use a bulkier insulating material for their radar, which was less effective."
http://www.icis.com/resources/news/2008/05/12/9122447/polyethylene-discovered-by-accident-75-years-ago/
https://en.wikipedia.org/wiki/Polyethylene
http://www.polymer-search.com/inventionplastic.html
http://www.acs.org/content/acs/en/education/whatischemistry/landmarks/polypropylene.html
http://www.independent.co.uk/news/science/polythenes-story-the-accidental-birth-of-plastic-bags-800602.html .
Wednesday, September 11, 2019
Radio Direction Finding
Plane Safety (1938) > .
Himmelbett Radar System - Luftwaffe | War Stories > .
Knickerbein >>> .
Secret War >> .
https://www.youtube.com/watch?v=fkCW4g8It_A&list=PLBYclEE4V19AiC_aSv3vbc6v0ms9o5qLV
4:55:45 > .
https://www.youtube.com/watch?v=GJCF-Ufapu8 .
Knickerbein > .
https://youtu.be/GJCF-Ufapu8?t=384 > .
German Radar detection & signals jamming in World War 2 (1943-Restored) > .https://www.youtube.com/watch?v=obFVkTN5lUI > .
Knickerbein >>> .
Secret War >> .
https://www.youtube.com/watch?v=fkCW4g8It_A&list=PLBYclEE4V19AiC_aSv3vbc6v0ms9o5qLV
4:55:45 > .
https://www.youtube.com/watch?v=GJCF-Ufapu8 .
Knickerbein > .
https://youtu.be/GJCF-Ufapu8?t=384 > .
Radio Research Station at Ditton Park, Slough
The Radio Research Station at Ditton Park, Slough
Unique record of the Earth’s ionosphere – the electrified region of the Earth’s upper atmosphere, was painstakingly recorded from 1933 onwards at the Radio Research Station near Slough.
Scientists at the RRS were monitoring the ionosphere as it was then vital for long-distance radio communications. Shortwave radio is reflected by the ionosphere and allows the signal to be transmitted long distances over the horizon.
They had noted that the density of the ionosphere was extremely variable and had set up the monitoring station in order to look for patterns in this variability. Much of this is due to changes in solar activity.
The ionosphere is created when x-rays and extreme ultraviolet light from the sun are absorbed by our atmosphere, electrifying it. We now know, thanks to a fleet of spacecraft monitoring the sun, that not all of this variability can be explained by solar activity. Attention is increasingly turning to sources from the lower atmosphere and the ground.
But where to find ground events capable of leaving a signature at the edge of space? The answer lies in the past. World War Two witnessed an explosive arms race, which culminated, in its most extreme form, in the atomic bomb.
But most destructive energy still came from conventional weapons. Allied aircraft dropped over 2.75m tons of TNT, the equivalent of 185 Hiroshimas.
The RAF’s four-engined Lancaster bomber with its 11-ton payload could deliver more explosive energy than any other aircraft in World War II. The American Liberator could carry six tons, the Luftwaffe’s Heinkel 111 four.
Individual British bombs also grew more deadly. In 1944, two six-ton “Tallboys” capsized the German Tirpitz battleship, and the 11-ton “Grand Slam” could start landslides. Such seismic events were, of course, few and far between. Most of Bomber Command’s effort was targeted not at specific installations, but whole cities.
Here, too, the scale of ordnance was devastating. The RAF and US Air Force dropped 42,500 tons of high explosive on Berlin alone, plus 26,000 tons of incendiary bombs.
So-called “blockbuster” bombs – two, four or even six-ton barrels of boosted TNT – fused to explode a few hundred feet up, would blow off roof tiles and shatter windows within 500 metres.
Direct hits pulverised whole apartment blocks. Aircraft flying a mile above the blasts could have parts blown off and the pressure wave could even collapse the lungs of those caught within it.
Subsequent incendiaries would then penetrate structures, designed to set off a firestorm. This only fully succeeded twice – in Hamburg in August 1943 and Dresden in February 1945 – when tens of thousands perished.
The strategic bombing war documents numerous other area bombing raids, each of which involved hundreds of aircraft and up to 2,000 tons of high explosive.
The German authorities’ punctilious recording of the times and payloads of raids, coupled with RAF Bomber Command mission logs, made it possible to construct a database of possible ground events which might have produced shockwaves capable of being detected in the ionosphere.
Ionospheric records from the Radio Research Station are now archived by the UK Solar System Data Centre at the Rutherford Appleton Laboratory, UK. The record shown below is for 08:30 on September 8, 1940, the morning after the start of the London Blitz when 700 tons were dropped by the Luftwaffe.
By combining data from 152 major bombing raids, it was possible to determine that the ionosphere was weakened, albeit only slightly, by these events.
https://theconversation.com/world-war-ii-bombing-raids-in-london-and-berlin-struck-the-edge-of-space-our-new-study-reveals-103951
Unique record of the Earth’s ionosphere – the electrified region of the Earth’s upper atmosphere, was painstakingly recorded from 1933 onwards at the Radio Research Station near Slough.
Scientists at the RRS were monitoring the ionosphere as it was then vital for long-distance radio communications. Shortwave radio is reflected by the ionosphere and allows the signal to be transmitted long distances over the horizon.
They had noted that the density of the ionosphere was extremely variable and had set up the monitoring station in order to look for patterns in this variability. Much of this is due to changes in solar activity.
The ionosphere is created when x-rays and extreme ultraviolet light from the sun are absorbed by our atmosphere, electrifying it. We now know, thanks to a fleet of spacecraft monitoring the sun, that not all of this variability can be explained by solar activity. Attention is increasingly turning to sources from the lower atmosphere and the ground.
But where to find ground events capable of leaving a signature at the edge of space? The answer lies in the past. World War Two witnessed an explosive arms race, which culminated, in its most extreme form, in the atomic bomb.
But most destructive energy still came from conventional weapons. Allied aircraft dropped over 2.75m tons of TNT, the equivalent of 185 Hiroshimas.
The RAF’s four-engined Lancaster bomber with its 11-ton payload could deliver more explosive energy than any other aircraft in World War II. The American Liberator could carry six tons, the Luftwaffe’s Heinkel 111 four.
Individual British bombs also grew more deadly. In 1944, two six-ton “Tallboys” capsized the German Tirpitz battleship, and the 11-ton “Grand Slam” could start landslides. Such seismic events were, of course, few and far between. Most of Bomber Command’s effort was targeted not at specific installations, but whole cities.
Here, too, the scale of ordnance was devastating. The RAF and US Air Force dropped 42,500 tons of high explosive on Berlin alone, plus 26,000 tons of incendiary bombs.
So-called “blockbuster” bombs – two, four or even six-ton barrels of boosted TNT – fused to explode a few hundred feet up, would blow off roof tiles and shatter windows within 500 metres.
Direct hits pulverised whole apartment blocks. Aircraft flying a mile above the blasts could have parts blown off and the pressure wave could even collapse the lungs of those caught within it.
Subsequent incendiaries would then penetrate structures, designed to set off a firestorm. This only fully succeeded twice – in Hamburg in August 1943 and Dresden in February 1945 – when tens of thousands perished.
The strategic bombing war documents numerous other area bombing raids, each of which involved hundreds of aircraft and up to 2,000 tons of high explosive.
The German authorities’ punctilious recording of the times and payloads of raids, coupled with RAF Bomber Command mission logs, made it possible to construct a database of possible ground events which might have produced shockwaves capable of being detected in the ionosphere.
Ionospheric records from the Radio Research Station are now archived by the UK Solar System Data Centre at the Rutherford Appleton Laboratory, UK. The record shown below is for 08:30 on September 8, 1940, the morning after the start of the London Blitz when 700 tons were dropped by the Luftwaffe.
By combining data from 152 major bombing raids, it was possible to determine that the ionosphere was weakened, albeit only slightly, by these events.
https://theconversation.com/world-war-ii-bombing-raids-in-london-and-berlin-struck-the-edge-of-space-our-new-study-reveals-103951
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sī vīs pācem, parā bellum
igitur quī dēsīderat pācem praeparet bellum therefore, he who desires peace, let him prepare for war sī vīs pācem, parā bellum if you wan...
