Materials Science Forum Vol. 1151

Abstract: Cellulose is an important structural material found naturally within the cell walls of plants that has recently been researched as a biodegradable, renewable, and non-toxic reinforcing agent used to improve properties for a variety of composite systems. Cellulose is usually derived from wood sources via acid hydrolysis. Bacterial cellulose (BC) is produced by bacteria proliferation using nitrogen, carbon, and oxygen sources, and is similar chemically to plant extracted cellulose. Compared to commercially available cellulose, BC has higher purity and increased hydrophilicity. In this work, banana peels are used as a carbon source for bacterial cellulose growth. The peels were heat treated to maximize sugar and carbon contents. In addition, BC derived from the banana peels doesn’t require any bleaching or chemical post-processing. In this research, BC derived from banana peels is synthesized, characterized, and analyzed for its physical, mechanical, and thermomechanical properties, as compared to commercial nanocellulose.

Abstract: Hair dye is a cosmetic product that is used to change the color of hair for beauty purposes. In this paper, a certain brand of hair dye is used as an example, and the bacterial revert mutation experiment is used to verify whether the hair dye will produce bacterial mutations. After testing, the brand hair dye is mutagenic negative, that is, it is not harmful to the human body and meets the standards for market sales.

Abstract: Classical linear contact mechanics, formulated with small strain and displacement assumption, struggles to accurately describe experiments involving rubbers and elastomers. Indeed, under high loads, these materials undergo large deformations and exhibit constitutive behaviors that deviate from a linear relationship between stress and strain. In such cases, it is essential to move beyond linear elasticity to account for nonlinearity caused by large deformations and displacements. Despite efforts to develop numerical tools capable of incorporating these non-linearities in contact problems, our understanding of their impact on contact mechanical responses remains limited. In this study, we investigate the basic case of normal contact between a wavy rigid indenter and a flat, deformable substrate. We examine the influence of geometric non-linearities, arising from large deformations and displacements, alongside material non-linearities, under both frictionless and frictional interfacial conditions. To this end, we developed a finite element model, and we compared its predictions with those of Westergaard’s fully linear theoretical model. The results indicate that even in frictionless contact scenarios, non-linearities produce a mechanical response that differs significantly from predictions based on linear theory. This discrepancy becomes more pronounced as the aspect ratio of the wavy indenter increases, thereby invalidating the small-displacement assumption inherent in linear models. Moreover, the presence of friction, coupled with geometric non-linearities, induces contact hysteresis during loading and unloading cycles a phenomenon often attributed to other interfacial behaviors such as adhesion and plasticity.

Abstract: This study presents a novel contribution to the research of graphene-based electro-optic modulators. In this paper, we numerically demonstrate an ultra-compact and efficient graphene modulator based on metal-nanoribbon integrated hybrid plasmonic waveguide. Benefiting from the good in-plane mode polarization matching and strong hybrid surface plasmon polariton and grapheme interaction, the 10 μm-length modulator can achieve good modulation performance with a wide modulation bandwidth of 41.3 GHz and a low energy consumption of 101 fJ/bit at 1.55 μm. These compact and energy-efficient optical modulators may have broad application prospects in the future optical communication systems.