Scholarly works in Agricultural and Environmental Engineering
Permanent URI for this collectionhttps://repository.ui.edu.ng/handle/123456789/568
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Item Moisture-dependent thermal properties of Cocoyam cormels(Faculty of Engineering, University of Maiduguri, Nigeria, 2019) Oyefeso, B. O.; Raji, A. O."Cocoyam (Xanthosoma sagittifolium) has served as a cheap carbohydrate source for many people in the developing countries with prospects in the production of animal feed, lager beer, and its starch as binding agent in drug formulation. Drying is an important unit operation in cocoyam processing and there appears to be lack of information on the thermal properties which are significant in designing heat treatment systems such as dryers for the cormels. This study therefore, investigated some thermal properties of X. sagittifolium cormels as affected by moisture content. Thermal properties namely thermal conductivity, diffusivity and specific heat of white- and pink-fleshed cocoyam cormels were investigated at moisture contents within the ranges of 130 to 395% and 85 to 200% (dry basis), respectively. The selected thermal properties of the cormels were determined with the aid of a thermal properties analyser which has a dual needle probe and uses transient line heat source method. Thermal conductivity, diffusivity and specific heat were within the ranges of 0.454 to 0.562 Wm-1K-1, 1.62×10-7 to 2.32×10-7 m2s-1, 1.836to 4.029 kJkg-1K-1, respectively for white-fleshed cocoyam and 0.489 to 0.601 Wm-1K-1, 1.79×10-7 to 2.65×10-7 m2s-1, 1.615 to 2.991 kJkg-1K-1, respectively for pink-fleshed cormels. Analysis of variance showed that there were significant differences between the measured properties at different moisture content levels. Regression models were established between the investigated thermal properties and moisture content.Item Effect of moisture content and loading orientation on elasticity of cocoyam cormel during transit and storage(International Commission of Agricultural and Biosystems Engineering (CIGR), 2017) Raji, A. O.; Oyefeso, B. O.Cocoyam (Xanthosoma sagittifolium) is one of the major staple food items in Nigeria. The crop is recently gaining attention and there is urgent need to intensify research efforts towards fully exploiting its promising potentials. Information on the elastic properties of the cocoyam cormels are necessary for understanding their behaviour under loading and in the design of equipment for proper handling of the cormels during processing and storage. This study investigated the effects of moisture content and orientation of loading on the elasticity of cocoyam cormels. White-fleshed and pink-fleshed varieties of the X. sagittifolium cormels were used for this study. The elastic properties of the cormels along the three mutually-perpendicular axes were determined. Deformation at rupture, modulus of elasticity (MOE), degree of elasticity (DOE) after first and third cycles along the longitudinal, cross-sectional and transversal directions ranged from 5.14 and 11.64 mm, 3.03 and 11.70 N mm-2, 0.51 and 0.73 mm, 0.45 and 0.70 mm, respectively. The degrees of elasticity of the cormels decreased with the increasing number of loading and unloading cycles thereby, limiting the stack height of cocoyam cormels in transit and storage to reduce mechanical damage and subsequent postharvest losses. The study provides the information which can serve as guidelines in ensuring proper handling of cocoyam cormels in transit and storage.