طراحي و ساخت ميز ارتعاشي به منظور مطالعه تاثير ارتعاش و نوع بسته بندي بر صدمات مكانيكي سيب گلدن دليشس

چكيده انگليسي :

95 Design and Development of Vibratory Table to Study the Effects of Vibration and Packaging Type on Mechanical Damages of Golden Delicious Apples Neda Mokhtari n mokhtari@ag iut ac ir June 27 2015 Department of Agricultural Machinery Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Porf Abbas Hemmat ahemmat@cc iut ac irAbstractMechanical damages to fruits and vegetables are mostly induced during harvest and postharveststages One of the sources of postharvest mechanical damage is fruit and vegetable transportation During fruit transportation mechanical damages are generated by vibration which is due tointeraction of the road and truck s suspension system Severity of fruit damages during vibrationdepends on characteristics of vibration frequency acceleration and duration of vibration fruit fruitvibratory characteristics transport type specification of vehicle suspension system road conditions vehicle speed fruit packaging type and position of fruit packages in the truck Apple is an importantproduct in our country and has a high production volume Fruits and vegetable are exposed tomechanical damages due to unsuitable storing packaging and transporting To study the effect ofpackaging type on the damages caused by vibration in this study a vibratory table was designed anddeveloped for the tests The design of the system was based on rotary unbalanced masses Thevibratory table consisted of two parts The first part is the suspension system which includes upperand lower springs and a fixed frame the second part includes the vibrating table and a movableframe and an eccentric mechanism which is installed on this part The eccentric mechanism includesmasses that are connected to rotary axes which rotate by a belt and pulley system In this study theeffects of vibration frequencies 9 and 13 Hz vibration during 30 and 60 min and packaging type net foam shredded paper and tray pack and position of each apple row in the box on the applebruising using a factorial experiment in a completely randomized design with three replications wereinvestigated The degree of damage on each apple was defined by a relative bruise index RBI Theindex is defined as the ratio of total bruise area on each apple to surface area of the same fruit Theeffect of vibration frequency vibration during packaging type and position of fruit row in the box onRBI was significant P 0 05 The lowest RBI was obtained at frequency of 13 Hz and vibrationduration of 30 minutes for the net foam packaging and the highest was obtain at frequency of 9 Hzand vibration duration of 60 minutes for the tray packaging After vibration test in order to study thevibration effects on the flesh strength penetration tests on the whole fruit and compression tests oncylindrical samples of apples were conducted The cubic equation of Henry and et al 2000 wasfitted to the force deformation of the compression tests The results showed that the effect ofvibration characteristics vibration frequency and duration as well as the effect of packaging typeand location row of apples in the box on the coefficients of a and c of the Henry s model was notsignificant However the effect of frequency on the b coefficient was significant P 0 05 and thevalues of this coefficient at frequency of 9 Hz was significantly higher than 13 Hz The effect ofvibration frequency and duration on the penetration force of the apple flesh was significant P 0 01 and the flesh strength was lowest at frequency of 13 Hz and duration of 60 minutes The effect offrequency vibration duration and type of packaging on the apple flesh fracture stress was significant Increasing the frequency and duration of vibration caused a reduction in the fracture strength of appleflesh failure point Therefor the vibration could have surface effect as bruising as well as bulkeffect as reduction in flesh strength Keywords mechanical damage packaging vibration frequency vibration acceleration fruitvibratory

مختاري، ندا

طراحي و ساخت ميز ارتعاشي به منظور مطالعه تاثير ارتعاش و نوع بسته بندي بر صدمات مكانيكي سيب گلدن دليشس

فركانس ارتعاش , شتاب ارتعاش , خصوصيات ارتعاشي ميوه , شاخص كوفتگي نسبي