Ergonomic Performance Evaluation of Date Stripping Process

Abstract

Al-Mabsili date processing is blended with traditional and cultural practices throughout the history of Oman. Due to the modernization in the society, there is a decline in Al-Mabsili date production due to labor scarcity and youth migration to cities looking for other types of jobs. The aim of this research was to study the potentials for mechanization of date stripping process and to compare the ergonomic performance of mechanical options with the traditional method. A mechanical stripping machine prototype was developed with three power source options; bicycle, exercise machine and electric motor. First two needed two operators, peddler and feeder, while electric motor and traditional method needed one. Ergonomic performance tests were using the standard discomfort evaluation methods created at Cornell University. Tests were conducted on human physiological parameters, energy spent, Cornell evaluation of whole-body discomfort, hands discomfort and seat comfort. Standard NIOSH lifting evaluation was conducted considering the frequency of lifting date bunches by operators. The results showed that in all power sources, significant increase in heartbeat, systolic and diastolic blood pressures, oxygen consumption and body temperature with date stripping activity. The energy expenditure per kg was highest in traditional method with14 kJ/kg, while bicycle and exercise machine had the higher energy expenditure rates of 25.7 and 24.3 kJ/min respectively. The Cornell whole-body postural discomfort evaluation showed the exercise machine with highest comfort level while the traditional method was the lowest. Neck and shoulders were the most affected areas in mechanical methods while hip, buttocks and lower back were most affected in traditional method. In Cornell hands discomfort evaluation, right hand was more affected than the left in all methods and first three fingers and the thumb were most affected. The Cornell seat comfort evaluation showed exercising machine is in more comfort zone (66.7%), bicycle in average zone (51.9%) and traditional method in poor comfort zone (9.3%). The average NIOSH lifting index was 0.54, a very satisfactory condition. The survey revealed that 90% respondents preferred electric motor as power source followed by bicycle.