Alow string shortcut to Material.add_element
Alow string shortcut to Material.add_element

samuelshaner/openmc,amandalund/openmc,amandalund/openmc,samuelshaner/openmc,wbinventor/openmc,smharper/openmc,amandalund/openmc,johnnyliu27/openmc,amandalund/openmc,paulromano/openmc,mit-crpg/openmc,bhermanmit/openmc,liangjg/openmc,wbinventor/openmc,mit-crpg/openmc,smharper/openmc,johnnyliu27/openmc,shikhar413/openmc,samuelshaner/openmc,smharper/openmc,shikhar413/openmc,paulromano/openmc,samuelshaner/openmc,walshjon/openmc,walshjon/openmc,walshjon/openmc,walshjon/openmc,liangjg/openmc,johnnyliu27/openmc,smharper/openmc,mit-crpg/openmc,paulromano/openmc,mit-crpg/openmc,liangjg/openmc,wbinventor/openmc,liangjg/openmc,wbinventor/openmc,bhermanmit/openmc,paulromano/openmc,shikhar413/openmc,shikhar413/openmc,johnnyliu27/openmc