Design, manufacture and evaluation of the new Instrument to Measure the ‎Friction Coefficient of Soil

Accurate determination of soil parameters such as the coefficient of internal friction, soil adhesion and soil-metal friction is essential for designing agricultural machinery, calculating the draft force and investigating the performance and wear of them. Tillage as the main operation is causing soil displacement and skidding on tillage equipment. Soil friction parameter against the tools that have wide contact surface with soil, increases the operating draft force and consequently energy consumption would be increased. This paper describes the design, fabrication and using a system for measuring the coefficient of soil external friction. The result showed that the changes of draft force versus normal load were linear and increasing the moisture increased soil external friction. Also, the results showed that the test system can discriminate between different soil textures and different contact surfaces tested. In general, according to the results the performance of the soil friction coefficient measuring device was acceptable

Poultry litter angle of wall friction

Dependence on chemical fertilizer is continually increasing.  Continual increasing of using chemical fertilizer causes nature pollution (e.g. water contamination).  This has led researchers to aggressively investigate renewable fertilizer resources and biomass to produce organic crops and reduced wastage.  Poultry litter is a bulk solid and biomass feed stocks. The angle of wall friction (AWF) is a critical factor in designing and constructing suitable equipment for pelletizing.  The results of this study showed that the simple effects of the moisture content (M) and surface types (S) as well as interaction of the S × particle size (P) and S × M were significant (

The effect of moisture content, particle size and consolidation stress on flow properties of vermicompost

 Physical properties of granular solids are essential to design appropriate, efficient, and economic bulk solids handling and storage equipment.  Flow of vermicompost is often restricted by caking and bridging, which occurs during transportation and storage.  This problem could be due to a number of factors including storage moisture, temperature, particle size, and consolidation stress.  There is lack of study on the effect of the mention factors simultaneously on flow index, cohesive strength and angle of internal friction of vermicompost.  The aims of this work were to discuss the primary factors affecting flowability of vermicompost as granular solids and powders, as well as using shear testing methodologies for this biomass material.  The experiments were conducted on samples selected from a wormy culture farm, Karaj, Iran, by Jenike’s shear cell technique.  The data was statistically analyzed using the three factors completely randomized design to study the effects of particle size, moisture content and consolidation stress on vermicompost flow properties.  The results showed that a significant difference between the flow index values at different stress levels.  Greater moisture content and smaller particle size caused poor flowability of vermicompost.  Increasing the moisture content and decreasing the particle size from 1.18 to 0.3 mm, the vermicompost reduced its flowability from free flowing at moisture content of 25% (w.b.) to cohesive at moisture content of 35% (w.b.).   Keywords: biomass flowability, flow index, shear test, vermicompost