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The paper reviews the application of the finite element method to the analysis of large‐deflection elasto‐plastic behaviour and traces the development of such a solution for plated structures. The accuracy of the approach is established by many comparisons with available solutions for isolated plates and conclusions are drawn on suitable idealizations for plated structures. The results of an analysis of a typical plate girder, allowing fully for the interaction between the component plates, are presented. Comparisons with experimentally measured values for the girder confirm the validity of the proposed approach for the study of the collapse modes of plated structures. The need for expensive experimentation is thereby reduced.

This paper aims to optimize feed moisture contents, barrel temperatures, blending ratios of maize and lupine for processing of protein-rich best quality extruded product using a twin-screw extruder.

A three-factor three-level response surface methodology by Box-Behnken Design was applied to evaluate the effect of selected processing conditions of blending ratios of lupine (10-20 per cent), barrel temperatures (120°C-150°C) and feed moisture content (14-18 per cent) on functional, nutritional and sensory characteristics of produced snack food.

The results of functional properties such as radial expansion ratio, bulk density, water absorption index, water solubility index observed as 0.71-1.2, 0.33-0.92 g/cc, 4.4-6.4 per cent and 10.2-15.1 per cent, respectively. The snack food showed the moisture 5.6-7.2 per cent, protein 8.1-18.1 per cent, fiber 1.6-2.7 per cent, ash 1.6-2.2 per cent and carbohydrate 64.8-81.4 per cent. The independent variables (lupine blending ratio, barrel temperature and feed moisture content) posed significant effects on expansion ration (p = 0.0030), bulk density (p = 0.0026), water absorption index (p = 0.0075) and water-solubility index (p = 0.0116). Higher blending ratio of lupine was increase in the bulk density and water solubility index, but decrease in expansion ratio and water absorption index of snack food. Higher feed moisture content was led to a reduction in expansion ratio and water-soluble index of snack food. Whereas, higher feed moisture contents was lead to rise in bulk density and water absorption index. Fiber (p = 0.0145), ash (p = 0.0343) and carbohydrate (p = 0.0001) contents were significantly depended on blending ratio. Blending of lupine 15.06 per cent, barrel temperature of 150 °C and feed moisture content of 14.0 per cent produced the snack food with desirability value of 72.8 per cent.

Protein malnutrition is one of the major problems in child development in under developed countries including Ethiopia. Maize is a top producer in the country but least appreciated for cost. Lupine is one of the undervalued produce consumed in Ethiopia after boiling. Still data on the utilization of maize and lupine in the extruded snack preparation was very limited. Optimization of moisture and barrel temperatures for this snack was not reported clearly yet.