Browsing by Author "Egwim Chidi Evans"

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    Design of a single screw extruder for homogenizing bulk solids
    (Agricultural Engineering International: The CIGR Journal, 2016) Adeshina Fadeyibi; Zinash Delebo Osunde; Gbabo Agidi; Egwim Chidi Evans
    The research was conducted to design a single screw extruder from locally available materials for the mixing and homogenization of bulk solids, such as the composites of cassava and yam starch-glycerol with nanoparticles. The design was made by computing the hopper outlet size, shaft diameter, screw geometry, barrel volume and the capacity of the conveyor, empirically. The stresses in the conical section of the hopper were also evaluated to assess its load requirement, thus avoiding any problem associated with the flow of materials through the hopper opening. The extruder was dynamically simulated to assess its throughput at the feeding, compression and metering zones. This was done by investigating the dynamic effect of the time of operation, with respect to the linear displacement, velocity and power, from the practical motion of the moving auger by Computational Fluid Dynamics method. The results showed that the vertical pressure acting downwards and the shear stress within the section were 37.02 and 6.44 kPa. The shaft diameter and screw geometry, which includes screw pitch and angle, were 20 and 56 mm, and 16.54o. The capacity of the extrusion conveyor and its power requirement were respectively, 18.46 tons/hour and 2.04 kW. The maximum linear displacement and velocity occur at the compression zone at every 3.03 rev/sec, which cause the bulk solid materials to melt, and are pushed by the resulting pressure into the metering zone. The relationship between the linear displacement and the time of operation obeys the power law. Consequently, a 5 hp electric motor was selected to power the single crew extruder.
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    Mixing Index of a Starch Composite Extruder for Food Packaging Application
    (CRC press, 2016) Adeshina Fadeyibi; Zinash Delebo Osunde; Gbabo Agidi; Egwim Chidi Evans
    This encapsulates the performance of a single-screw extruder for use in the mixing and homog-enization of the composite of cassava starch (1000 g),glycerol (45%‒55% w/v), and zinc oxide nanopar-ticles (0%‒2% w/v), based on the mixing index and rate constant. The machine was designed such that itcan accommodate two diameters (5 and 7 mm) in thebreaker plate; the output/1000 g of the starch compos-ite was determined at a resident time of 5  min over aperiod of 1 h machine operation. The research revealedthat the composite containing 55% w/v glycerol, 1% w/vzinc nanoparticles and 5 mm diameter of the holes inthe breaker plate has the highest mixing rate constant(k = 0.527). Decay trends were observed as the mixing index increases with an increase in the resident time in the range of 45%–55% w/v glycerol concentration and a decrease in the output per 1000 g of the starch compos-ite through both the 5 and 7 mm diameters of the hole of the breaker plate. The optimum output of the machine, whose desirability function is closer to the optimization goal, gave 0.53/1000 g. The amount of unmixed com-posite was significantly lower than the machine output and thus the single-screw extruder can be used to quan-tify and monitor mixing behavior of starch composites in the food industry.