Exposure of whole body vibration(WBV)influences performance,comfort,and long term health risks of tractor operator.Therefore,measurement and evaluation of WBV parameters should be carried out to find probable effects ...Exposure of whole body vibration(WBV)influences performance,comfort,and long term health risks of tractor operator.Therefore,measurement and evaluation of WBV parameters should be carried out to find probable effects on the health of tractor operators.In this study,a system was designed to measure the WBV of agricultural tractor operators and evaluated the hazard risks on operator’s body according to the ISO standards,and implementation of the WBV test in the official testing station was also suggested.A tri-axial accelerometer was employed to measure vibrations transmitted to the seated operator body as a whole through the supporting surface of the buttock on four typical farm roads under different speeds.The vector sum A(8)exposures on the rough tracks(earthen and grassland roads)exceeded the action limits of 0.5 m/s2 at a 10.9 km/h forward speed and reached to the action limit value at a 16.0 km/h forward speed on the concrete road.The vector sum of VDV(8)exposures did not exceed the action limits of 9.1 m/s1.75 and was greater on the grassland road.The vector sum Sed(8)exposures values exceeded the moderate probability of an adverse health limit of 0.5 MPa on all farm roads at high forward speeds and exceeded the high probability of an adverse health limit of 0.8 MPa on asphalt,concrete,and grassland roads which should be lower than the exposure limit values as suggested by the ISO and EC standards.The WBV evaluation procedure should be considered for implementation at the official tractor test station,which would response to domestic and international tractor test regulations and improve the market competitiveness.展开更多
The main purpose of the study was to determine the economic parameters and effective schedules for tractor operation.Secondary data from various sources were used in this research.Some essential data were collected fr...The main purpose of the study was to determine the economic parameters and effective schedules for tractor operation.Secondary data from various sources were used in this research.Some essential data were collected from primary sources through survey.Operating costs were calculated and project financial profitability was determined by four major factors on farm financial measurement techniques,namely,benefit-cost ratio(BCR),net present value(NPV),internal rate of return(IRR),and payback period.Considering the economic use,land topography and cropping pattern was developed to effective scheduling for tractor operation.The operating cost of tractor with implement was found to be US$9.25 per hectare.For replacement of the existing tractor on expiry of economic life,the entrepreneur has to save an amount of US$219 per year in a bank account.Based on the operating cost,annual savings for replacement and a profit margin for the entrepreneur,the rent-out charge of the tractor is estimated at US$11.58 per hectare.Considering 10%interest rate,the NPV of the tractor at existing condition is US$18757.The NPV of tractor indicates that tractor entrepreneurship is considered financially sound and the project is financially viable,with an average IRR of 36.96%.This is because IRR of the tractor was higher than the bank interest rate and it is highly profitable from the viewpoint of individual investors.The Payback period of tractor with implement was determined as 2.03 yrs.The minimum tenure for an economic use of a common tractor used in agriculture is about 6310 hrs.Above this critical use,the utilization of a tractor is economical for a tractor entrepreneur.Depending on the cropping pattern two major and one minor turn-around periods are available in between cropping seasons for tilling operation.The time available for tilling of land is estimated about 140 days at 12 hours a day in a year.To strengthen the existing capacity of the tractor customer hire service entrepreneurs and develop new entrepreneur,appropriate adoption and dissemination programs must be launched in all over Bangladesh.展开更多
文摘Exposure of whole body vibration(WBV)influences performance,comfort,and long term health risks of tractor operator.Therefore,measurement and evaluation of WBV parameters should be carried out to find probable effects on the health of tractor operators.In this study,a system was designed to measure the WBV of agricultural tractor operators and evaluated the hazard risks on operator’s body according to the ISO standards,and implementation of the WBV test in the official testing station was also suggested.A tri-axial accelerometer was employed to measure vibrations transmitted to the seated operator body as a whole through the supporting surface of the buttock on four typical farm roads under different speeds.The vector sum A(8)exposures on the rough tracks(earthen and grassland roads)exceeded the action limits of 0.5 m/s2 at a 10.9 km/h forward speed and reached to the action limit value at a 16.0 km/h forward speed on the concrete road.The vector sum of VDV(8)exposures did not exceed the action limits of 9.1 m/s1.75 and was greater on the grassland road.The vector sum Sed(8)exposures values exceeded the moderate probability of an adverse health limit of 0.5 MPa on all farm roads at high forward speeds and exceeded the high probability of an adverse health limit of 0.8 MPa on asphalt,concrete,and grassland roads which should be lower than the exposure limit values as suggested by the ISO and EC standards.The WBV evaluation procedure should be considered for implementation at the official tractor test station,which would response to domestic and international tractor test regulations and improve the market competitiveness.
文摘The main purpose of the study was to determine the economic parameters and effective schedules for tractor operation.Secondary data from various sources were used in this research.Some essential data were collected from primary sources through survey.Operating costs were calculated and project financial profitability was determined by four major factors on farm financial measurement techniques,namely,benefit-cost ratio(BCR),net present value(NPV),internal rate of return(IRR),and payback period.Considering the economic use,land topography and cropping pattern was developed to effective scheduling for tractor operation.The operating cost of tractor with implement was found to be US$9.25 per hectare.For replacement of the existing tractor on expiry of economic life,the entrepreneur has to save an amount of US$219 per year in a bank account.Based on the operating cost,annual savings for replacement and a profit margin for the entrepreneur,the rent-out charge of the tractor is estimated at US$11.58 per hectare.Considering 10%interest rate,the NPV of the tractor at existing condition is US$18757.The NPV of tractor indicates that tractor entrepreneurship is considered financially sound and the project is financially viable,with an average IRR of 36.96%.This is because IRR of the tractor was higher than the bank interest rate and it is highly profitable from the viewpoint of individual investors.The Payback period of tractor with implement was determined as 2.03 yrs.The minimum tenure for an economic use of a common tractor used in agriculture is about 6310 hrs.Above this critical use,the utilization of a tractor is economical for a tractor entrepreneur.Depending on the cropping pattern two major and one minor turn-around periods are available in between cropping seasons for tilling operation.The time available for tilling of land is estimated about 140 days at 12 hours a day in a year.To strengthen the existing capacity of the tractor customer hire service entrepreneurs and develop new entrepreneur,appropriate adoption and dissemination programs must be launched in all over Bangladesh.
