I love slide rules and dial calculators, there are so many you rarely see the same one twice. These complex beauties are from a collection of Nuclear slide rules and dials gathered together by ORAU (Oak Ridge Associated Universities).
They've got dials to calculate radiation dosage, Nuclear bomb effects, Nuclear weapon effects, x-ray exposure, decay rates, treatment times and Radium exposure. A much more useful collection than mine, which mainly consists of vintage promotional pieces!
See the full collection of Nuclear slide rules here and see some of mine here.