Ahmed K. Abdelmoety, Taha H.A. Naga and Youssef F. Rashed
This paper aims to develop a new isogeometric boundary element formulation based on non-uniform rational basis splines (NURBS) curves for solving Reissner’s shear-deformable…
Abstract
Purpose
This paper aims to develop a new isogeometric boundary element formulation based on non-uniform rational basis splines (NURBS) curves for solving Reissner’s shear-deformable plates.
Design/methodology/approach
The generalized displacements and tractions along the problem boundary are approximated as NURBS curves having the same rational B-spline basis functions used to describe the geometrical boundary of the problem. The source points positions are determined over the problem boundary by the well-known Greville abscissae definition. The singular integrals are accurately evaluated using the singularity subtraction technique.
Findings
Numerical examples are solved to demonstrate the validity and the accuracy of the developed formulation.
Originality/value
This formulation is considered to preserve the exact geometry of the problem and to reduce or cancel mesh generation time by using NURBS curves employed in computer aided designs as a tool for isogeometric analysis. The present formulation extends such curves to be implemented as a stress analysis tool.
Details
Keywords
Ummi Nur Ain Abdul Razak, R.M. Taha, Siti Aisha Na’illa Che Musa and Normadiha Mohamed
The purpose of this paper is to evaluate the potential of betacyanin pigment extracted from Hylocereus polyrhizus fruit pulp and peel as a natural colorant and to observe the…
Abstract
Purpose
The purpose of this paper is to evaluate the potential of betacyanin pigment extracted from Hylocereus polyrhizus fruit pulp and peel as a natural colorant and to observe the effects of pH and light on betacyanin contents.
Design/methodology/approach
In this study, pigment from the pulp and peel of H. polyrhizus fruits was extracted using 80 per cent methanol and 80 per cent acetone. Effects of pH and light exposure during storage on betacyanin content were evaluated. The betacyanin extract, mixed with 20 per cent poly(methyl methacrylate) and coated onto glass slides, was tested with different concentrations of sodium hydroxide (NaCl) to determine its durability. An ultraviolet (UV)–visible spectrophotometer was used for analyzing the betacyanin content.
Findings
Betacyanin pigment extracted from pulp using 80 per cent acetone as the solvent at pH 1.0 had the highest betacyanin content. Betacyanin content decreased when stored under exposure of light compared to storage in dark. In this study, increasing concentration of NaCl decreased the absorbance values at faster rates for betacyanin-coated glass slides.
Research limitations/implications
Acetone is volatile and evaporates rapidly. Pigments extracted with acetone were stored in glass vials which were closed tightly to prevent evaporation.
Social implications
The social implication is the use of natural pigments from cactus species as a valuable and eco-friendly source in a coating system without adverse effects for human health.
Originality/value
The method for detection of stability and effectiveness of betacyanin pigment used as a natural colorant for coating application was beneficial and recent for environment-friendly and natural plant-based product development.