Nicoleta Ungureanu

Calculus Elements for Mechanical Presses in Oil Industry

Oil products industry produces edible and inedible oils. About 2/3 of total oil products are the edible oils, which are used directly in foods or in the manufacture of margarine, mayonnaise, bakery and pastry products, cooking fats, preserves etc. The remaining 1/3 of the total volume of produced oil are the technical oils, used in the production of various products, such as: de‐ tergents, paint, glycerin, fatty acids, varnish, pharmaceuticals or cosmetics (Banu, 1999).

Grinding Characteristics of Wheat in Industrial Mills

Grinding of cereal seeds is due to the mechanical action of several forces: compression, shearing, crushing, cutting, friction and collision, to which seeds are subjected, depending on the design if the mill used for grinding (roller mill, hammer mill, stones mill or ball mill). By applying these forces, when the mechanical resistance of the particles is exceeded, their division happens in a number of smaller particles of different sizes, geometric shapes, mass‐ es and volumes.

FEM Modeling of Stress Distribution and Displacement in Clayey Soils during Artificial Compaction

Knowledge of soil behavior under compressive loads is important in order to prevent or minimize the impact of soil compaction on the environment and agricultural production. The aim of this study was to simulate the behavior of a clayey soil under wheel loads applied by an agricultural trailer. For known characteristics of the soil, wheel loads of 4.5 kN and 21 kN and tire inflation pressures of 180, 240 and 300 kPa, were obtained the models of stress distribution and soil displacement. For 300 kPa tire inflation pressure and 21 kN wheel load, were obtained: maximum stress of 175 kPa concentrated in the topsoil at about 140 mm depth, with smaller significant values distributed to 380 mm, and maximum soil displacement of 28.1 mm.

FEM modelling of soil behaviour under compressive loads

Artificial compaction is one of the most dangerous forms of degradation of agricultural soil. Recognized as a phenomenon with multiple negative effects in terms of environment and agricultural production, soil compaction is strongly influenced by the size of external load, soil moisture, size and shape of footprint area, soil type and number of passes. Knowledge of soil behavior under compressive loads is important in order to prevent or minimize soil compaction. In this paper were developed, by means of the Finite Element Method, various models of soil behavior during the artificial compaction produced by the wheel of an agricultural trailer. Simulations were performed on two types of soil (cohesive and non-cohesive) with known characteristics. By applying two loads (4.5 kN and 21 kN) in footprints of different sizes, were obtained the models of the distributions of stresses occuring in the two types of soil. Simulation results showed that soil stresses increase with increasing wheel load and vary with soil type.