Synthesis of Vegetable Oil‐Based Polyurethane: A Study on Curing Kinetics Behavior

In the present study, biobased polyurethane (BPU) samples were synthesized from three different polyols along with polymeric hexamethylene diisocyanate. The three different polyols were synthesized by reacting castor oil with ethylene glycol, triethylene glycol, and triethanolamine. The synthesized polyols were confirmed using proton nuclear magnetic resonance (¹H NMR) spectra analysis. BPU samples were confirmed by the disappearance of isocyanate peak in the FTIR spectra. The cross‐linking densities of all BPU samples were determined using swelling studies. Curing kinetics behavior of all BPU samples were analyzed using differential scanning calorimetry at three different heating rates (5, 7.5, and 10°C/min). The curing kinetic parameters were studied using three nonisothermal methods such as Kissinger, Flynn–Wall–Ozawa, and Ozawa, respectively. The activation energies were found to increase with increasing degree of cure (α). Surface properties of all the synthesized BPU samples were evaluated by dynamic mechanical analysis and scanning electron microscopy.     

Ultrasonic velocities and elastic constants in tin-indium alloys

Ultrasonic velocities, elastic constants and internal friction are studied in Sn-In alloys in the concentration range of 0 to 30 wt% of In using composite oscillator technique. Anomalies observed in the vicinity of the phase transitions of these alloys at fourteen concentrations are interpreted in the light of the phase changes in the phase diagram.     

Epoxy‐based composite adhesives: Effect of hybrid fillers on thermal conductivity,rheology, and lap shear strength

Thermal management is an important parameter in an electronic packaging application. In this work, three different types of fillers such as natural graphite powder (Gr) of 50‐μm particle size, boron nitride powder (h‐BN) of 1‐μm size, and silver flakes (Ag) of 10‐μm particle size were used for thermal conductivity enhancement of neat epoxy resin. The thermal properties, rheology, and lap shear strength of the neat epoxy and its composite were investigated. The analysis showed that the loading of different wt% of Gr‐based fillers can effectively increase the thermal conductivity of the epoxy resin. It has also been observed that the thermal conductivity of the hybrid filler (Gr/h‐BN/Ag) reinforced epoxy adhesive composite increased six times greater than that of neat epoxy resin composite. Further, the viscosity of hybrid filler reinforced epoxy resin was found to be increased as compared with its virgin counterpart. The adhesive composite with optimized filler content was then subsequently subjected to determine single lap shear strength. The degree of filler dispersion and alignment in the matrix were determined by scanning electron microscopy (SEM) analysis.     

Biobased polyurethane adhesive over petroleum based adhesive: Use of renewable resource

This review article is based on the recent trends and development of biobased polyurethane (PU) adhesives from vegetable oil. A detail discussion has been reported about the PU adhesive starting from petroleum based to biobased source. Special attention has been given towards the utilization of castor oil based PU in adhesive technology, due to the wide range of castor oil among all vegetable oil. The appreciable adhesion, mechanical, thermal properties of vegetable oil based PU adhesives were compared with petroleum based PU adhesive, which were utilized to meet the specific application in adhesion industry.     

Myricitrin,a Glycosyloxyflavone in Myrica esculenta Bark Ameliorates Diabetic Nephropathy via Improving Glycemic Status,Reducing Oxidative Stress,and Suppressing Inflammation

The present study evaluated the therapeutic potential of myricitrin (Myr), a glycosyloxyflavone extracted from Myrica esculenta bark, against diabetic nephropathy. Myr exhibited a significant hypoglycemic effect in high fat-fed and a single low-dose streptozotocin-induced type 2 diabetic (T2D) rats. Myr was found to improve glucose uptake by the skeletal muscle via activating IRS-1/PI3K/Akt/GLUT4 signaling in vitro and in vivo. Myr significantly attenuated high glucose (HG)-induced toxicity in NRK cells and in the kidneys of T2D rats. In this study, hyperglycemia caused nephrotoxicity via endorsing oxidative stress and inflammation resulting in the induction of apoptosis, fibrosis, and inflammatory damages. Myr was found to attenuate oxidative stress via scavenging/neutralizing oxidative radicals and improving endogenous redox defense through Nrf-2 activation in both in vitro and in vivo systems. Myr was also found to attenuate diabetes-triggered renal inflammation via suppressing NF-κB activation. Myr inhibited hyperglycemia-induced apoptosis and fibrosis in renal cells evidenced by the changes in the expressions of the apoptotic and fibrotic factors. The molecular docking predicted the interactions between Myr and different signal proteins. An in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) study predicted the drug-likeness character of Myr. Results suggested the possibility of Myr to be a potential therapeutic agent for diabetic nephropathy in the future.     

Numerical procedure for second order non-linear ordinary differential equations and application to heat transfer problem

In this paper, we have first given a numerical procedure for the solution of second order non-linear ordinary differential equations of the typey″ = f (x;y, y′) with given initial conditions. The method is based on geometrical interpretation of the equation, which suggests a simple geometrical construction of the integral curve. We then translate this geometrical method to the numerical procedure adaptable to desk calculators and digital computers. We have studied the efficacy of this method with the help of an illustrative example with known exact solution. We have also compared it with Runge-Kutta method. We have then applied this method to a physical problem, namely, the study of the temperature distribution in a semi-infinite solid homogeneous medium for temperature-dependent conductivity coefficient.