THE EFFECTS OF WASTEWATER IRRIGATION ON AGRICULTURAL SOILS

In arid and semi-arid areas, wastewater is often recovered for crop irrigation, contributing to the sustainable agriculture. Although positive effects have been observed on crop yields (50-80% growth) due to wastewater nutrients, the reuse of untreated wastewater harms both the environment and human health. Soil is mostly affected by excess salts, sodium, nutrients and heavy metals in wastewater. High salinity affects the upper layer of soil (0–30 cm); sodium and chlorine reduce crop yields by 40%; high content of organic matter in wastewater decreases soil pH, and heavy metals and pathogens enter the food chain. Irrigation technology is also important: sodium and salinity are higher in sprinkler than in furrow or subsurface irrigation; subsurface drip irrigation is more effective in reducing soil pathogens than surface drip irrigation. This paper examines the effects of wastewater irrigation on soil salinity, sodium, heavy metals and pathogen contamination

ANALYSIS OF THE STATE OF STRESSES AND STRAINS IN THE CURVED STILT, USING TRIANGULAR FINITE ELEMENTS (CST)

The paper presents a study on the analysis of the distribution of stresses and strains in the curved stilt of the plough-body, using the Finite Element Method. Modeling was performed with the help of triangular finite elements "CST" (Constant Strain Triangle), using a special program for this type of applications “CSTPL.EXE”, developed at University Politehnica of Bucharest, Department of Materials Strength

STRUCTURAL STATIC ANALYSIS OF THE CURVED STILT BY FEM USING THE ELCUT PROGRAM

The paper presents a study of the distribution of stresses and strains in the curved stilt of the plough-body, using the ELCUT analysis program by the finite element method. In its public version, the program allows the static structural analysis in three stages of precision. However, there are some limitations on the number of nodes for the discretized structure, depending on its complexity (250 to 500 nodes)