A modified Burzynski criterion for anisotropic pressure-dependent materials

In this paper the Burzynski criterion, which was introduced for isotropic pressure-dependent materials, is modified for anisotropic pressure-dependent materials in plane-stress condition. The modified criterion can be calibrated with 10 experimental data points such as tensile stress at 0°, 45° and 90°, compressive stress at 0° and 90° and R-values in tensile stress at 0°, 45° and 90° from rolling direction and also biaxial tensile stress and tensile R-value. To identify the anisotropic parameters an error function is set up through comparison of the predicted yield stresses and R-values with those from experiments. Then the Downhill simplex method is applied to solve 10 high-nonlinearity equations. Finally, considering Al 2008-T4 (BCC), Al 2090-T3 (FCC), AZ31 (HCP) and also Mg–0.5% Th alloy, Mg–4% Li alloy, pure textured magnesium, textured magnesium and Ti–4Al–1/4O ₂, which are HCP materials with \( \bar{\varepsilon }^{p} = 1\% ,5\% ,10\% \) as case studies and comparing the results for the modified Burzynski criterion with experiments, it is shown that the Burzynski criterion is appropriate for pressure-dependent anisotropic materials with proper accuracy.     

Fracture analysis of functionally graded materials with U‐ and V‐notches under mode I loading using the averaged strain‐energy density criterion

One of the most powerful criteria to predict the critical fracture load in plates with notches is the strain‐energy density averaged over a well‐defined control volume ahead of the notch tip. Although the averaged strain‐energy density (ASED) criterion has been proposed for homogeneous materials, it has been shown in this paper that this criterion can also be applied for non‐homogeneous materials, especially for functionally graded materials (FGMs). A numerical method has been used to evaluate the control volume boundary, the averaged strain‐energy density over the control volume, and also the critical fracture load in FGMs under mode I loading. A new set of experimental results on fracture of blunt V‐notched samples made of austenitic–martensitic functionally graded steel under mode I loading have been provided.     

Effects of guar gum and arabic gum on the physicochemical,sensory and flow behaviour characteristics of frozen yoghurt

This study investigated the effect of guar gum and arabic gum on physicochemical, sensory and flow behaviour properties of frozen yoghurt. The results indicated that gums significantly affected the viscosity, overrun and melting rate of frozen yoghurt. The highest overrun value was observed in sample containing 0.5% arabic gum. Frozen yoghurt containing 0.3% guar gum had the highest viscosity. The longest first dripping time was observed in sample containing 0.5% arabic gum. Flow behaviour of samples showed that all frozen yoghurts exhibited shear thinning behaviour. Guar gum at a concentration of 0.2% and arabic gum at a concentration of 0.5% presented the best total acceptability. The results of this study revealed that the frozen yoghurt produced with arabic gum had the better overall sensory and physicochemical characteristics.     

Fractionation of Extracts and Crystalline and Non-Crystalline Proteins from White Kidney Beans (Phaseolus vulgaris) by Ion-Exchange High-Performance Liquid Chromatography

Sodium hydroxide solution (0.02%) and citric acid solutions (0.08N, pH 5.5, CA1; 0.60N, pH 3.5, CA2) were used to extract proteins from white kidney beans (Phaseolus vulgaris). The extracts were subjected to ion-exchange high performance liquid chromatography (IE-HPLC) using a phosphate elution buffer (20 mM, pH 7.0). The charge properties of the protein fractions present in the NaOH extract and the CA1 and CA2 extracts were similar although the relative proportion of total peak area represented by each fraction was different in the different extracts. IE-HPLC of the isoelectric precipitate (amorphous microstructure) isolated from the CA1 (bipyramidal crystalline microstructure) and the CA2 (spheroidal microstructure) extracts indicated striking differences in the charge properties of the proteins which constituted the isolates. IE-HPLC also demonstrated that the precipitation processes did not affect the charge properties of the proteins which remained after the proteins were recovered from the different extracts.