8170

7568

كارشناسي ارشد

مكانيك ماشينهاي كشاورزي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي

1392

چهارده،98ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

عباس همت

حميد هاشم الحسيني، محسن پيرمراديان

3/9/92

احمد ميره اي، ميلاد فتحي

مهندسي كشاورزي

ID7568

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

99 Effect of Variety and Harvesting Time on Some Mechanical Properties of Apple and its Bruise Susceptibility Under Quasi Static Loading Bentolhoda Ghasemibaghbadrani b ghasemibaghbadrani@ag iut ac ir Date of Approval April 20 2013 Department of Agricultural Machinery Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M sc Language FarsiSupervisor Prof A Hemmat ahemmat@cc iut ac irAbstractApple having the second ranking of country production after citrus is one of the major orchard products ofIran Iran being forth apple producing country has a large portion in exporting this product Therefore it isnecessary for Iran to preserve and improve its place among apple producing countries by increasing quantityand quality of the fruit Minimizing mechanical damage during harvest and postharvest operations is one ofthe main factors increasing apple fruit quality There are little studies on apple handling in Iran thusharvesting transportation and packaging of apple is performed mostly by hand labor More research can therefore encourage the producers to adopt mechanization of these stages and subsequently morecommercial production and more revenue In this study some physical and rheological properties of threeapple varieties Kahanz Golab Jonagold and Fuji at three harvest dates were determined using confined andunconfined compression tests The firmness of apple flesh and skin was also measured using a penetratingprob Using a specialized direct shear box shear strength of the flesh was also measured Spherical indenterand parallel plate tests were performed in order to study apple susceptibility to bruising at four loading levels 1 2 3 and 4 mm and the bruise volume was then measured after 24 hours Threshold of degree of elasticityand of absorbed energy for avoiding mechanical damage to apple was determined The bruise susceptibilityof the three apple varieties was compared using bruise and bruise harmonic indices bruise susceptibility andbruise resistance criteria Finally Kahanz Golab apple of the first harvest under quasi static loading wassimulated assuming elastic and visco elastic behaviors using obtained parameters Stress strain and absorbedenergy at failure mechanical properties measured using compression test on cylindrical samples themaximum penetrating force penetration test on intact fruit and the shear strength of the fruit flesh measured using direct shear box were mostly affected by apple variety and harvest date The resultsindicated that the minimum and maximum values of the measured parameters were obtained for KahanzGolab and Fuji apples respectively Comparing bruise volume of three apple varieties in three harvest dates it was concluded that the bruise susceptibility increased along with the fruit maturity Fuji appledemonstrated the highest resistance to mechanical damages compared to the others Failure criterion forapple flesh in tested apples was maximum shear stress Modeling of apple as a visco elastic sphere in Abaqussoftware assuming constant bulk modulus could properly simulate apple behavior under quasi static loading Keywords Kahanz Golab apple Jonagold Fuji physical property rheological property firmness shear strength finite element

عباس همت

حميد هاشم الحسيني، محسن پيرمراديان

احمد ميره اي، ميلاد فتحي