In this article, the modified coupled Korteweg-de Vries equation with Caputo and Caputo-Fabrizio time-fractional derivatives are considered. The system is studied by applying the modified double Laplace transform decomposition method which is a very effective tool for solving nonlinear coupled systems. The proposed method is a composition of the double Laplace and decomposition method. The results of the problems are obtained in the form of a series solution for $0<\alpha \le 1$, which is approaching to the exact solutions when $\alpha =1$. The precision and effectiveness of the considered method on the proposed model are confirmed by illustrated with examples. It is observed that the proposed model describes the nonlinear evolution of the waves suffered by the weak dispersion effects. It is also observed that the coupled system forms the wave solution which reveals the evolution of the shock waves because of the steeping effect to temporal evolutions. The error analysis is performed, which is comparatively very small between the exact and approximate solutions, which signifies the importance of the proposed method.

The purpose of fins or extended surfaces is to increase the dissipation of heat from hot sources into their surroundings. Fins like annular fins, longitudinal fins, porous fins, and radial fins are used on the surface of equipments to enhance the rate of heat transfer. There are many applications of fins, including superheaters, refrigeration, automobile parts, combustion engines, electrical equipment, solar panels, and computer CPUs. Based on a wide range of applications, the effects of stretching/shrinking on a fully wet trapezoidal fin with internal heat generation is investigated. The shooting approach is used to calculate the trapezoidal fin's thermal profile, tip temperature, and efficiency. It is observed that with an increase in the shrinking and wet parameter, the temperature distribution decreases and efficiency increases. On the other hand, when stretching increases, the temperature distribution increases and efficiency diminishes. Using the computed results, it is concluded that shrinking trapezoidal fins improves the effectiveness and performance of the system.