A computer-controlled injector of the type having a motor which advances and retracts a plunger located within a syringe housing toward and away from a nozzle located in the front of the syringe to inject fluid into or out of an animal subject. The abnormality handling section performs initial solution generation when it is determined that performed optimization is abnormal. The parasol opening device is movable along the post between an open position and a closed position. In addition, layers of chrome oxide, spinel and aluminum oxide can be used. The first end of the tube is in fluid communication with at least one tank outlet.