No abstract

Fruits are usually graded according to their quality. The purpose of the grading is to grad fruit into uniform categories (according to size, shape, weight, color and ripening stage). So fruit can be classified to different grades according to the requirements of the market. Due to the lack of the small grading machinery for small farms and the high prices of large grading machinery, this study aimed to designing, manufacturing and performance evaluating of a prototype for orange grading based on the dimensions of the fruit, which take place without physical contact. The prototype uses different successively operating components, such as phototransistors and actuators, each performing a specific task. The operating principle depend on the phototransistor, signal gathering circuit a processing circuit and output circuit for distributing unit. When it works, the system receives digital signals produced by fruits that shadow the light from a phototransistor sensor during fruit measuring. These digital signals processed by an electronic circuit and the fruit's sizing level are deduced. Then, the system will output switch signals to open the sorting switches according to fruits' size. Testing of the grading prototype results was statistically factorial in completely randomized design, featuring three control factors (conveyor chain velocity, sphericity percentage of fruit and stopping time) and three performance evaluation parameters (grading efficiency, damage percentage and productivity). The result showed that the best degree of grading efficiency obtained with the best degree of damage percentage were at 0.15m/s chain velocity and 1.5 sec Stopping time. The best obtained values of grading efficiency were (92.2%) with (7.1%) damage fruit. The energy required was 160.2 Watt/h.

Drying of agricultural products is the great importance for preservation of food by human beings. Solar drying refers to a technique that utilizes incident solar radiation to convert it into thermal heat energy for drying purposes. The drying operation is mainly affected by variation of the air drying temperature, air flow rate and air relative humidity. The research was carried out to study the drying characteristics of okra to achieve highly drying rates and good quality. Three similar drying units were designed and manufactured in the Faculty of Agricultural., Menoufiya University and installed on the roof of Agricultural Engineering building. Each unit consists of solar collector, drying chamber, drying trays, chimney, and suction fan. Drying characteristics of okra treated by 1.0%sodium carbonates at boiling point for three minuets under different drying systems and flow rates of air 0.075 m 3 /sec, 0.149 m 3 /sec, and 0.249 m 3 /sec at the same time. Computer program used to define the fit mathematical model described the dying curves of okra in different conditions. The obtained results showed that, indirect dryer for drying okra at air flow rate of 0.075 m 3 /sec achieved the best quality. The drying efficiency was decreased as, the moisture content of okra crop reduced.

Physical characteristics and some major chemical properties of potato tubers (Diamond and Santana varieties) at fresh, cured and stored in two storage systems stages were investigated. Nawalla traditional storage system at 16+3  C; 84% relative humidity and Cold storage system at 4  C; 90 RH were used in the investigation. The storage period after curing stage was 75 days. This period was divided into 3 sub periods every 25 days. Physical characteristics included physical dimensions, shape, weight analysis, actual and calculated volumes, particle and bulk densities, , surface area, particle density, repose angle, static coefficient of friction on different surfaces (rubber, steel and wood), firmness, penetration resistance, impact height and the percentage of bruised tubers due to free falling on steel. While, chemical properties included the changes of moisture content and sugar concentration of tubers. Statistical and regression analysis were conducted to the obtained data.

Physical characteristics of wheat grains of three varieties, Giza-168, Sakha-93 (white wheat) and Banisuife-1 (durum) at different levels of moisture contents (% w.b) were investigated. Physical characteristics included dimensions, spherisity, weight of one thousand grains, particle and bulk density, porosity, angle of repose and static coefficient of friction on four different surfaces (plywood, galvanized iron, stainless-steel and rubber-sheet) at four different levels of moisture content ranged from (9 to 18% w.b). Each of major dimensions, spherisity, weight of one thousand grains, dynamic angle of repose and static coefficient of friction appeared a linear increasing with increasing the moisture content, while both bulk and particle densities decreased linearly in the studied range. As for porosity of wheat grains of Giza-168 and Banisuife-1, it increased linearly with increasing grains moisture content while the porosity of Sakha-93 variety showed a negative relationship.