A Numerical and Experimental Investigation of Dimple Effects on Heat Transfer Enhancement with Impinging Jets

This research was aimed at studying the numerical and experimental characteristics of the air flow impinging on a dimpled surface. Heat transfer enhancement between a hot surface and the air is supposed to be obtained from a dimple effect. In the experiment, 15 types of test plate were investigated at different distances between the jet and test plate (B), dimple diameter (d) and dimple distance (Er and Eθ). The testing fluid was air presented in an impinging jet flowing at Re = 1500 to 14,600. A comparison of the heat transfer coefficient was performed between the jet impingement on the dimpled surface and the flat plate. The velocity vector and the temperature contour showed the different air flow characteristics from different test plates. The highest thermal enhancement factor (TEF) was observed under the conditions of B = 2 d, d = 1 cm, Er= 2 d, Eθ = 1.5 d and Re = 1500. This TEF was obtained from the dimpled surface and was 5.5 times higher than that observed in the flat plate

A Novel Safety Holder Device Designed for Securing the Endotracheal Tube in Neonates with Severe Respiratory Conditions

This article introduces an inventive holder for endotracheal tubes designed specifically to support neonates with severe respiratory conditions during ventilation. Its primary goal is to minimize the risk of slippage of ventilator tubes in newborns, a critical concern that can lead to complications in their respiratory health. The innovation accommodates endotracheal tube equipment by offering adjustable sizing to match different dimensions. The development process employs computer-aided design (CAD) principles, while prototypes are crafted using three-dimensional (3D) printing technology. Comprising four main components—a support for the endotracheal tube header, a support for the tube unit itself, a flexible structure for tube positioning, and a stabilizing base—the innovation demonstrates structural strength and suitability within predefined parameters. It effectively supports the endotracheal tube apparatus while providing flexibility in positioning and distance adjustments. Importantly, its height can be tailored to suit the newborn’s head, offering adaptability for optimal usage. This research supports Sustainable Development Goals (SDGs) 3 and 9 relating to “Good health and well-being” and “Industry, innovation and infrastructure”

High Performance Composites Based on Highly Filled Glass Fiber-Reinforced Polybenzoxazine for Post Application

Glass fiber post based on the new polymeric material, polybenzoxazine, is prepared and the effects of glass fiber contents on mechanical and thermal properties are evaluated. The mechanical response to externally applied loads of tooth restored with glass fiber-reinforced polybenzoxazine composite posts is also simulated by finite element analysis of a tridimensional model and compared with the response to that of a natural tooth. The reinforcing of glass fiber can help improve the mechanical and thermal properties of the polybenzoxazine influenced by the interfacial adhesion between the glass fiber and polybenzoxazine matrix, except for the relatively high mechanical property of the glass fiber. The mechanical data, i.e., elastic modulus under flexure load or flexural modulus by three-point bending test of the glass fiber-reinforced polybenzoxazine composites are agreed with the elastic modulus of dentin and then used in the finite element model. The restoration using the glass fiber-reinforced polybenzoxazine composite post provided the maximum von Mises equivalent stress at the cervical third area of the endodontically treated tooth model as similarly observed in the natural tooth. In addition, the maximum von Mises equivalent stress of the tooth restored with the glass fiber-reinforced polybenzoxazine composite post is also quietly like that of the natural tooth. The finding of this work provided the essential properties of the glass fiber-reinforced polybenzoxazine composite for dental restorations and appliances