A scientific report on heat transfer analysis due to generated and absorbed heat over an oscillatory stretching sheet: a finite difference-based study.

A non-Newtonian liquid motion across a stretchable surface is relevant to various industrial applications, including extruding plastic sheets and stretching plastic films. In connection with this, the impact of endothermic and exothermic chemical reactions on the flow of rate-type liquid via an oscillatory stretching sheet in the presence of permeable media with the Maxwell liquid model is elucidated in the present study. Scientists and engineers may enhance the efficiency of chemical reactions or heat transmission by optimising system flow and investigating the effect of reactions on flow dynamics.

Chain-End Controlled Depolymerization Selectivity in α,α-Disubstituted Propionate PHAs with Dual Closed-Loop Recycling and Record-High Melting Temperature.

Within the large poly(3-hydroxyalkanoate) (PHA) family, C3 propionates are much less studied than C4 butyrates, with the exception of α,α-disubstituted propionate PHAs, particularly poly(3-hydroxy-2,2-dimethylpropionate), P3H(Me)P, due to its high melting temperature ( ∼ 230 °C) and crystallinity (∼76%). However, inefficient synthetic routes to its monomer 2,2-dimethylpropiolactone [(Me)PL] and extreme brittleness of P3H(Me)P largely hinder its broad applications. Here, we introduce simple, efficient step-growth polycondensation (SGP) of a hydroxyacid or methyl ester to afford P3H(Me)P with low to medium molar mass, which is then utilized to produce lactones through base-catalyzed depolymerization.

A scanning electron microscope analysis on the effect of bleaching gel in combination with fluoro calcium phosphosilicate-based dentifrice on whitening of teeth and dentinal tubule occlusion - An study.

Aim: The aim of this study is to investigate the use of 15% carbamide peroxide in combination with fluoro calcium phosphosilicate desensitizing dentifrice during bleaching to evaluate postoperative dentinal tubule occlusion.

Materials And Methods: Premolars which were extracted and bleached using 15% carbamide peroxide with fluoro calcium phosphosilicate dentifrice were used in this investigation, and the shade change was assessed. They were subsequently divided into sections and examined with scanning electron microscope.

Unraveling the Mechanism of Catalyzed Melt-Phase Polyester Depolymerization via Studies of Kinetics and Model Reactions.

Developing a mechanistic understanding of catalyzed melt-phase depolymerization processes is of utmost importance to the rapidly expanding field of circular polymers with a closed chemical loop. Herein, we present a methodology to probe the mechanism of metal-catalyzed melt-phase depolymerization of polyesters utilizing an approach centered on studies of kinetics by thermogravimetric analysis and model reactions. Kinetic parameters associated with the prototypical Lewis-acid-catalyzed depolymerization of representative polyesters, including poly(δ-valerolactone) (PVL), poly(lactic acid), and poly(γ-butyrolactone), are elucidated.