03/01/2017 Development / java script

this is the demo

the secret is:  ng-selected="true"

        <md-input-container>
            <label for="aggregation">Aggregation:</label>
              <md-select ng-model="aggregation">
                <md-option ng-value="Select" ng-selected="true">Select</md-option>
                <md-option><em>Hour</em></md-option>
                <md-option><em>Day</em></md-option>
                <md-option><em>Week</em></md-option>
              </md-select>
          </md-input-container>