This research presents a study about extrudate swell properties of high density polyethylene melts in annular die extruded in a capillary rheometer through 3 types of annular die: normal annular die convergent annular die and divergent annular die. Each type of die had a die gap of 1mm 1.5 mm and 2 mm respectively. Results of the experiment showed that extrudate swell of high density polyethylene melts occurred in both diameter swell and thickness swell ratio. The swell measured in all 3 types of die tended to be higher with the increase of shear rate and the decrease of 2 mm 1.5 mm to 1 mm die gap by an average of 12%. This occurrence could be explained from measurement of flow properties in all 3 types of die which had increasing shear stress due to the decrease of die gap by an average of 10%. Moreover it was also found that the thickness swell ratio was higher than the diameter swell by an average of 45% in all sizes of die gap. This could be explained from the Stress distribution which was more dense at the mandrels surface when the die gap of annular die decreased.

This research aims to design and construct small-scale angular rotary macadamia nut cracker machine using angular rotary striking mechanism. The proposed machine can crack 3 sizes of macadamia nuts - 17-22 mm 23-28 mm and 29-34 mm diameter with no need for separation size before feeding into the machine. Results of the experiment showed that the proposed angular rotary macadamia nut cracker machine could be used exactly as designed. Its average efficiency in separating sizes before cracking was 83% with overall productivity of 7.75 kilograms per hours. With regard to cracking process it was found that weight of the cracked macadamia nut was 29.75% of the whole macadamia fruit. The other 70.25% was weight of the shell. Furthermore it was also found that regarding quality of the cracked macadamia nuts the whole-nut quality was 39% the half-nut quality was 44% and the broken- nut quality was 17% respectively.