Add-PSSnapin Microsoft.SharePoint.Powershell -EA 0 

$databases = ("Content_Upgrade_AU","Content_Upgrade_NZ","Content_Upgrade_CA","Content_Upgrade_US","Content_Upgrade_Projects")

foreach ($db in $databases)
  {
    $DbServer = "SQL-12"
    $webApp = "http://projects.contoso.local"
    Mount-SPContentDatabase -name $db -webapplication $webApp -DatabaseServer $DbServer
  }