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20162
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Subject: Farm, Machinery and Power × End date: 2016 × Start date: 2016 × Thesis Type: M.Tech. ×
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    ThesisItemOpen Access
    Development of low cost electrostatic spray-charging system for liquid formulations
    (Department of Farm Power Machinery and Energy, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2016) Dipak Khatawkar, S; KAU; Dhalin, D
    The introduction of electrically charged sprays in agricultural application has become inevitable for better control on droplet transference with reduced drift and increase in application efficiency with less spray chemical requirements. In the present study was under taken to develop an electrostatic induction spray charging system as attachment to powered knapsack mist-blower. A high voltage generator was fabricated on the basis of Cockcroft-Walton voltage multiplier principle with input of 6 V DC battery to provide high voltage required at the developed charging electrode assembly (Model III, Model IV and Model V) for inducing electrostatic charge on spray droplets. As the existing (Model I) and redesigned (Model II) nozzle failed to give fine atomization, a self-atomizing hydraulic nozzle was developed for delivering the droplet spectrum required for effective electrostatic charge induction. The three working models (III, IV and V) were evaluated for charge to mass ratio (mC.kg-1) at five electrode potentials (1 kV, 2 kV, 3 kV, 4 kV and 5 kV), four electrode placement positions (0 mm, 5 mm, 10 mm and 15 mm) and five distances (50 cm, 100cm, 150 cm, 200 cm and 250 cm) from the nozzle. Model V with electrode voltage potential at 5 kV and EPP at 5 mm shown the maximum CMR value (1.088 mC.kg-1), followed by Model III (0.888 mC.kg-1) and Model IV (0.777 mC.kg-1) with same combination of variables. In contrast with commercial system (ESS-MBP90) it was observed that except at 50 cm distance from nozzle, Model V (at 4 kV and 5 kV) surpassed commercial system in CMR from 100 cm to 250 cm distance. To avoid air blast injury of plant, the nozzle has to be 100 cm to 150 cm away from the plant. The droplet spectrum of the developed system was analysed and observed that the size of droplets were 100 to 200 μm. The deposition efficiency of the developed system was on par with that commercial unit, and was within the range of 60 to 70 per cent. The developed system found to be cost effective and significantly consistent than the commercial system.
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    ThesisItemOpen Access
    Ergonomic investigations on hand arm vibration of brush cutter for the development of a vibration reducing aid
    (Department of Farm Power Machinery and Energy, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2016) Aswathi, K; KAU; Sureshkumar, P K
    Brush cutters are widely used in Kerala for weeding and clearing fields. While operating brush cutters, certain amount of vibration is transmitted to human body.Extended exposure to mechanical vibration can induce degeneration of the vascular and sensio-neural systems in the hand called hand-arm vibration syndrome (HAVS).The hand-arm vibration syndrome (HAVS) is a complex condition associated with vibration exposure and the use of hand-held vibrating machines. The vibration exposure of worker can be decreased by proper selection and maintenance of tool. To study the ergonomic aspects and hand transmitted vibrations of brush cutters, six subjects (3 male & 3 female) were selected who arehaving experience in operation of brush cutter.A suitable vibration reducing aid for brush cutters is designed and fabricated keeping the view that it should be capable of transmitting at least a part of the vibration produced at cutter head to the ground.It should be easily attached or detached from the brush cutters shaft.The material used for the vibration reduction aid should be light in weight and sturdy, so that it could be raised along with the cutter head by the operator. According to the conceptual design, a vibration reduction aid is developed and field tested. It consists of parts viz. curved arms, fixture to arms, quick fixing locks, ground rollers, rollers fixture and rubber grip. The brush cutter and vibration reducing aid is evaluated in the field with different cutter heads viz. nylon rope, 2 blade, 3 blade and circular blade. The experiment is repeated for 2-stroke and 4-stroke models of brush cutters operated by male and female subjects. The energy expenditure for brush cutter operation is calculated for two models of brush cutter for all subjects and compared. A statistical analysis is conducted using MSTAT software and found that the developed vibration reducing aid, blade and type of internal combustion engine have significant effect on vibration excitation in both right and left handles of brush cutters selected. The proposed method of evaluating occupational risk related to mechanical vibration exposure while working with brush cutter makes it possible to account the effect of attachment, cutter head and type of internal combustion engine. Subjective ratings like ODR, OER, OSR and BPDS also indicated significant effect of reducing vibration due to the vibration reducing aid.