The present study aimed to determine and recognize the physical ans mechanical properties as an important role in designing and developing of specific machines and their operations such as planting, harvesting and grading, Physical characteristics of corn kernels were obtained of two varieties: White Dent Corn single hybrid 10 (Corn 10), and yellow Dent Corn single hybrid 162, (Corn 162).For each of the physical characteristics, corn 10 gave the highest values comparing with corn 162. For each of the material surfaces, the galvanized surface gave the lowest static coefficient of friction (0.531 , 0.459)for corn 10 , corn 162 respectively; and for the same group, the plywood surface gave the highest value (0.624 , 0.586) for the two varieties respectively. For the painted surfaces, the oven -baked enamel processed paint gave the lowest values (0.48, 0.5) for the two varieties comparing with Polish paint, Mutt paint, and untreated mild -steel surfaces which gave (0.828, 0.72 -0.72, 0.71 -0.572, 0.549) respectively. INTRODUCTION ata on physical properties of agro-food materials are valuable because: they are needed an input to models predicting the quality and behavior of produce in sowing, handling, preharvest, harvest, and post-harvest situations; and aid the understanding of food processing. (Nesvadba, et. al. 2004 ) mentioned that physical characteristics of the material such as shape, size, volume, density , surface area and coefficient of friction are important and essential engineering data in design of machine structures, and controls, in analyzing and determining ____________________________________________

The main aim of this research was to increase the operation efficiency of agricultural tractor to suit the conditions and potentials of the Egyptian farmer. This leads to increase the rates of the feddan production and raise the value of the yield per feddan. This meets the requirement to achieve the strategic goals of the agricultural development by modifying and developing the modern technology, especially the agricultural tractors to suit the local environment in all agricultural operations, including plowing. Laboratory experiments and statistical analysis for the data of the research were run and hydraulically steering was designed by suing a closed hydraulic circuit for the tractor. The main results obtained from the experiments are summarized in the following main points: 1. Mathematical equations are derived to find the steering angles. 2. Decreasing the repeated technical problems in the steering equipments of the tractors. 3. Decreasing the operation, maintain and used spare parts in the steering equipments of tractors. 4-The modification suits all the agricultural operations even for small holdings in Egypt. INTRODUCTION he agricultural tractor is the backbone of the Egyptian agriculture because it does all the different field processes. It must be improved to suit the conditions and potentials of the Egyptian farmer to increases the efficiency of its operation. This study aims to develop steering in particular. It aims to design a mechanism which can be controlled hydraulically to work on the front land-wheels. Louis and Kersey (1938) mentioned that correct steering of wheels should be in planes which are tangential to their respective paths.

The experimental field work, carried out on the design of gated pipes system for testing, was locally made in the workshop in Esna village, Esna city, Qena Governorate. The main objective of the experimental field work was carried out in field to study the performance of gated pipe system tested to determine the head and discharge along gated pipeline. The flow variation was investigated through 30 meter long pipe of 160 mm outside diameter, with closed end having 40 gated pipes of 38 mm diameter. The orifice can be closed by sliding gate to about 46.6%. Therefore, the discharge regulation of flow through orifices along the gated pipes was about 53.4%.

Series of laboratory experiments were conducted to investigate the filtration performance of different types of filter media under different operating conditions, and to study their influence on the emitter clogging problems. The emitter clogging problem under these different operating conditions was investigated. Five different emitter types were used. The statistical split-split-split plot design was chosen for this study. Obtained results indicated that, Sedimentation loads is the second most important factor affecting the media filter performance. Using high sedimentation loads of 50 and 100 mg/L affected drastically the removal efficiency. An improvement of the removal efficiency due to increasing filter bed depth from 30 to 50 cm was noticed. The susceptibility to clogging of the tested emitter types varied according to its emitter type, sedimentation loads, and removal efficiency. Obtained results indicated that the use of crushed silica and crushed basalt (2) media types, E-2 and Supertif emitter types under operating condition of at least 50 cm and sedimentation loads of 10 to 20 mg/L contributed to better performance of the trickle-irrigation system.

Tillage erosion is one of the main causes of land degradation. The objective of the present study is to evaluate the effect of tillage systems (up and downslope and contour tillage), soil conditions (consolidated and loosened soils), tillage depth, speed and slope on tillage erosion rate. Field experiments of variable slopes (3-16%) were established on sandy soil of Wadi El Ramala, west Mersa Matruh City. Soil translocation as affected by tillage systems and soil conditions were examined. In addition, soil losses by tillage erosion and water erosion were measured and evaluated. The experimental results showed that the average displacement distance is a function of gradient slopes, soil condition, tillage system, depth and speed. The validation of the soil translocation model developed by (Van Muysen et al 2000), under different gradient slopes, tillage depth, speed and soil condition were evaluated. This validation showed that variations in tracer displacement distance can be successfully predicted. Consequently, such model can be used under sandy soil. Finally, experiment results showed that tillage operations with a chisel plow under present agricultural practices are responsible for the major field redistribution of soil. Furthermore, it is clear that tillage of a loosened soil is far more erosive than tillage of a consolidated soil, where the tillage transport coefficient (K) was 105 kg.m-1 per tillage operation for consolidated soil and 179 kg.m-1 for loosened soil under contour tillage. However, 256 kg.m-1 per tillage prevailed for consolidated soil and 454 kg.m-1 for loosened soil under up and downslope tillage treatments.