عنوان :
مطالعه و مدل سازي فرآيند خشك كردن ژل آلوئه ورا به روش خورشيدي
مقطع تحصيلي :
كارشناسي ارشد
گرايش تحصيلي :
مكانيك ماشين هاي كشاورزي
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي
صفحه شمار :
نه،82ص.: مصور،جدول،نمودار
يادداشت :
ص.ع.به فارسي و انگليسي
استاد راهنما :
مرتصي صادقي
تاريخ نمايه سازي :
1/3/92
استاد داور :
احمد ميره اي، ميلاد فتحي
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي
چكيده انگليسي :
Investigation and Modeling of Solar Drying Process of Aloe vera Aloe barbadensis Miller Gel Sayed Hasan Emami sh emami@ag iut ac ir January 2013 Depatment of Farm Machinery Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Morteza Sadeghi sadeghimor@cc iut ac ir AbstractAloe vera Aloe barbandensis Miller is an ancient plant being used since before Christ This plant isknown as a source of valuable elements used in functional foods cosmetics and pharmaceuticals The gelextracted from aloe vera is effective in treating many diseses High moisture content is a prominentfeature of aloe vera leaves On the other side the powder obtained from the dehydrated gel is commonlyused for producing the by products Therefore drying of aloe vera gel is of great importance Dryingprocess is one of the oldest methods of food preservation based on removal of moisture from product viacomplex procedures of simultaneous heat and mass transfer In most commonly used dryers energy isusually provided by fossil fuels High expenses environmental contamination and diminishing of fossilenergy sources besides not being available in different urban and rural areas are some disadvantages ofusing fossil energies Solar thermal technology is rapidly developing in agricultural practices as analternative clean and renewable energy In this regard many solar dryers have been designed andfabricated In present study aloe gel slabs with dimensions of 10 10 100 mm and initial moisturecontent of 99 43 were dried using oven hot air open sun natural and forced convection solar dryingmethods A photovoltaic system was designed and installed to supply the electrical power required for thesolar dryer fan The color values L a and b antioxidant activity and drying duration of different dryingmethods were determined and compared Fourteen empirical and semi theoretical models were fitted toexperimental data to find the best model describing drying process based on the statistical parameters R2 RMSE and SSE Oven and sun dried samples indicated the best and the worst qualities regarding colorvalues respectively The highest and lowest antioxidant activities were respectively observed in hot airand solar dried samples Forced convection solar drying method took the longest drying time while hotair drying method needed the shortest Wang and Singh model satisfactorily predicted the drying processunder oven hot air open sun and forced convection drying methods However Midili et al modelpresented the best fit to natural convection solar drying data The results obtained from the numericalsolution of Fick s second law based on finite difference method in two dimensional geometry indicatedan acceptable compatibility to the experimental data Key Words Aloe vera Drying Solar Dryer Mathematical Modeling MoistureDiffusity
استاد راهنما :
مرتصي صادقي
استاد داور :
احمد ميره اي، ميلاد فتحي
