title: Conversion of Time stamp to seconds
body: <p>I have a set of timestamps in this format "13:09:56.176 ... up till say "13:46:09.145". I am interested in extracting the seconds only so that the output reads from 0 to say 2000 seconds. 
  I am not particular about the time the data capturing started but just the duration. </p>
  
  <p>I tried splitting the columns in Excel to extract the seconds eg 56.176 but was not able to sequence them.</p>