- Polonium is a chemical element; it has symbol Po and atomic number 84. A rare and highly radioactive metal (although sometimes classified as a metalloid) with no stable isotopes, polonium is a chalcogen and chemically similar to selenium and tellurium, though its metallic character resembles that of its horizontal neighbors in the periodic table: thallium, lead, and bismuth. Due to the short half-life of all its isotopes, its natural occurrence is limited to tiny traces of the fleeting polonium-210 (with a half-life of 138 days) in uranium ores, as it is the penultimate daughter of natural uranium-238. Though longer-lived isotopes exist, such as the 124 years half-life of polonium-209, they are much more difficult to produce. Today, polonium is usually produced in milligram quantities by the neutron irradiation of bismuth. Due to its intense radioactivity, which results in the radiolysis of chemical bonds and radioactive self-heating, its chemistry has mostly been investigated on the trace scale only.
- Interstate 94 (Wikipedia)
Interstate 94 (I-94) is an east–west Interstate Highway connecting the Great Lakes and northern Great Plains regions of the United States. Its western terminus is just east of Billings, Montana, at a junction with I-90; its eastern terminus is in Port Huron, Michigan, where it meets with I-69 and crosses the Blue Water Bridge into Sarnia, Ontario, Canada, where the route becomes Ontario Highway 402. It thus lies along the primary overland route from Seattle (via I-90) to Toronto (via Ontario Highway 401) and is the only east–west Interstate Highway to have a direct connection to Canada.