6 research outputs found
Visco-elastic and physico-mechanical properties of bananas and plantains by quasi-static and dynamic methods
ThesisThesis, University of Guelph, 199
Relationship between the Angle of Repose and Angle of Internal Friction for Agricultural Granular Materials
Tanzania Journal o Agriculture Science 1998, Vol. 1(2): pp 187-194The angles of repose and internal friction are important parameters which determine the flow
characteristics of agricultural granular materials, such as flour, maize, beans, wheat, sorghum
and rice. The angles have a big influence on the design offlow and storage structures of
agricultural materials such as hoppers, silos, bunkers and bins because they determine
whether the flow will be smooth or not, and whether the bursting forces in relation to vertical
forces will be great or not. An apparatus for determination of the angle of repose was specifically
designed for the purpose. The a'ngles of repose for three different grains, namely maize,
sorghulll and rice at four moisture content levels, namely 10, 15, 20 and 25%wb were determined
using the designed apparatus. A tri-axial compression machine was used to determine
the angles of internal friction for the same grains and same moisture contents. The data obtained
were fed into SAS statistical software for step-wise regression analysis. A model of the
form r = 22.35 + 0.013 2; + 0.019[MC] 2 where r = the angle of repose, 1 = angle of
intemlilfriction and MC = percent moisture content on wet basis was established, and used
to predict the angleofreposefor the tested grains ~ith high accuracy (R2 = 0.97). It was
concluded that the angle of repose was consistently higher than the angle of internal friction
for all the granular materials tested, and the angle of internal friction was highest for maize,
followed by rice and finally sorghum
Effect of variety on the heat transfer coefficient during drying of fermented ground cassava
Assesssment of the Perfomance of sun drying of maize grains on perforated surfaces
Tanzania Journal of Agriculture Science 1998, Vol. 1(2): pp 195-197Sun drying of maize grains on different mesh sizes ofperjorated trays using different heights
from the ground was investigated. The mesh sizes used were 1.5 mm and 3 mm at the elevations
of 30, 60 and 90 cm. The results show that both mesh size and height from the ground affect
the drying rate and seed viability. The combination of90 cm elevation and 3mm mesh size
gave the highest drying rates and lowest seed viability loss