نتایج جستجو برای: railroads

تعداد نتایج: 583  

2008
Erik Johansson Teodor Sommestad Mathias Ekstedt

Society is increasingly dependent on the proper functioning of the electric power system, which in turn supports most other critical infrastructures: water and sewage systems; telecommunications, internet and computing services; air traffic, railroads and other transportation. Many of these other infrastructures are able to operate without power for shorter periods of time, but larger power out...

Journal: :Minutes of the Proceedings of the Institution of Civil Engineers 1886

Journal: :The Mississippi Valley Historical Review 1958

Journal: :Journal of the Franklin Institute 1912

Journal: :Political Science Quarterly 1929

Journal: :Journal of Political Economy 1922

2010
Mark Leach

A field survey was begun in 1986 to determine the status of prairie vegetation on railroad rights-of-way in Wisconsin. Two % of 849 sample points located at 1.6 km intervals along railroads were found to contain relatively high quality prairie, and 23 % contained slightly degraded prairie. A significant proportion of these remnants contained mesic prairie, a community type which today is almost...

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