PENGARUH KECEPATAN PUTARAN PISAU DAN JENIS BAHAN TANAMAN TERHADAP KINERJA POWER THRESHER MODIFIKASI PADA PROSES PENCACAHAN TANAMAN = THE EFFECT OF BLADE ROTATION AND KIND OF PLANT ON THE PERFORMANCE OF MODIFIED POWER THRESHER ON CHOPPING PLANTS - APRIYANA, TESA (2018)