Static and Fatigue Debond Resistance between the Composite Facesheet and Al Cores under Mode-1 in Sandwich Beams

The debonding toughness between unidirectional glass fiber reinforced polymer face sheets and cellularic cores of sandwich structures is experimentally measured under static and fatigue loading conditions. The effect of various core geometries, such as regular honeycomb and closed-cell foams of two relative densities on the adhesive interfacial toughness is explored using the single cantilever beam (SCB) testing method. The steady-state crack growth measurements are used to plot the Paris curves. The uniformity of adhesive filleting and the crack path was found to affect the interfacial toughness. The static Mode-1 interfacial toughness of high-density foam cores was witnessed to be maximal, followed by low-density honeycomb, high-density honeycomb, and low-density foam core. Similarly, the fatigue behavior of the low-density honeycomb core has the lowest crack growth rates compared to the other samples, primarily due to uniform adhesive filleting

Static and fatigue debond resistance between the composite facesheet and Al cores under Mode-1 in sandwich beams

The debonding toughness between unidirectional glass fiber reinforced polymer face sheets and cellularic cores of sandwich structures is experimentally measured under static and fatigue loading conditions. The effect of various core geometries, such as regular honeycomb and closed-cell foams of two relative densities on the adhesive interfacial toughness is explored using the single cantilever beam (SCB) testing method. The steady-state crack growth measurements are used to plot the Paris curves. The uniformity of adhesive filleting and the crack path was found to affect the interfacial toughness. The static Mode-1 interfacial toughness of high-density foam cores was witnessed to be maximal, followed by low-density honeycomb, high-density honeycomb, and low-density foam core. Similarly, the fatigue behavior of the low-density honeycomb core has the lowest crack growth rates compared to the other samples, primarily due to uniform adhesive filleting.Published versio

Stability of Boundary Value Discrete Fractional Hybrid Equation of Second Type with Application to Heat Transfer with Fins

The development in the qualitative theory of fractional differential equations is accompanied by discrete analog which has been studied intensively in recent past. Suitable fixed point theorem is to be selected to study the boundary value discrete fractional equations due to the properties exhibited by fractional difference operators. This article aims at investigating the stability results in the sense of Hyers and Ulam with application of Mittag–Leffler function hybrid fractional order difference equation of second type. The symmetric structure of the operators defined in this article is vital in establishing the existence results by using Krasnoselkii’s fixed point theorem. Banach contraction mapping principle and Krasnoselkii’s fixed point theorem are employed to establish the uniqueness and existence results for solution of fractional order discrete equation. A problem on heat transfer with fins is provided as an application to considered hybrid type fractional order difference equation and the stability results are demonstrated with simulations

A Study of Generalized Hybrid Discrete Pantograph Equation via Hilfer Fractional Operator

Pantograph, a device in which an electric current is collected from overhead contact wires, is introduced to increase the speed of trains or trams. The work aims to study the stability properties of the nonlinear fractional order generalized pantograph equation with discrete time, using the Hilfer operator. Hybrid fixed point theorem is considered to study the existence of solutions, and the uniqueness of the solution is proved using Banach contraction theorem. Stability results in the sense of Ulam and Hyers, and its generalized form of stability for the considered initial value problem are established and we depict numerical simulations to demonstrate the impact of the fractional order on stability

Asymptotic Stability of Nonlinear Discrete Fractional Pantograph Equations with Non-Local Initial Conditions

Pantograph, the technological successor of trolley poles, is an overhead current collector of electric bus, electric trains, and trams. In this work, we consider the discrete fractional pantograph equation of the form Δ∗β[k](t)=wt+β,k(t+β),k(λ(t+β)), with condition k(0)=p[k] for t∈N1−β, 0<β≤1, λ∈(0,1) and investigate the properties of asymptotic stability of solutions. We will prove the main results by the aid of Krasnoselskii’s and generalized Banach fixed point theorems. Examples involving algorithms and illustrated graphs are presented to demonstrate the validity of our theoretical findings

Expanding the anti-flaviviral arsenal: Discovery of a baicalein-derived Compound with potent activity against DENV and ZIKV.

10.1016/j.antiviral.2023.105739ANTIVIRAL RESEARCH22

Calcination-Dependent Morphology Transformation of Sol-Gel- Synthesized MgO Nanoparticles

© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Sol-gel synthesis is a widely accepted method of producing nanoparticles with high surface area-to-volume ratio and purity at relatively low temperatures. For metal oxide nanoparticle synthesis, sol-gel maintains a good metal oxide composition with controlled chemical structure and the ability to fine-tune morphology and size. Magnesium oxide (MgO) nanoparticles possess unique physicochemical characteristics that have enabled a wide range of applications from catalysis to disease treatment. The potential features of MgO nanoparticles are significantly affected by their shape and size. However, research investigating the thermo-molecular mechanisms governing the size and shape formation of MgO nanoparticles during sol-gel synthesis is limited. This study investigates the effect of sol-gel synthesis conditions on the shape and size as well as other functional features of MgO nanoparticles. The results demonstrated that the size and shape alterations of MgO nanoparticles were dependent on changes in calcination temperature and also the presence of periclase phase along with their crystallinity and functional groups. TEM analysis showed the morphological evolution during the synthesis process from spherical to hexagonal and from hexagonal to rod shape. By varying the calcination temperature and gelling agent composition in sol-gel synthesis, MgO nanoparticles with different size distributions and morphologies can be generated for various applications. The current study reveals that the gelling agent is responsible for sol-gel phase formation which eventually affects the calcination temperature for the formation of morphologically different MgO nanoparticles