(Portland, OR)  --  Those wishing to vote in today's primary election need to submit ballots by eight o'clock tonight.  Multnomah County elections officials are expecting a high participation rate this time, even though only 25-percent of ballots had been turned in by last Friday.  Tim Scott with the Multnomah County Election Division tells KATU-TV that the presidential primary election, the Portland mayor's race and the gas tax could drive an increase in the turnout.