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Two giant tunnelling machines are starting work on a 10-mile tunnel
under the Chiltern Hills in England for the new High-Speed 2 rail line from London to Birmingham, Manchester, and Leeds. The machines are named "Florence" for nurse Florence Nightingale and "Cecilia" for Cecilia Payne-Gaposhkin, pioneering astronomer. Each machine is 170m long and as they cut away at the rock (chalk) the spoil is removed by conveyor and sections of concrete wall are inserted behind the cutting face. They can dig about 15m per day and the job will take three years. I understand that the concrete wall segments are being formed on the machine and transported forward to the newly cut rock face where they are fitted together. Cecilia Payne was born in Britain and was the first astronomer to show that stars were more or less all of the same composition, mainly Hydrogen and Helium and a few percent metals, with the differences in spectra caused by their effective temperatures and not their compositions. -- Mike Dworetsky -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
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