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Many studies have investigated natural convection heat transfer from the outside surface of horizontal and vertical cylinders in both constant heat flux and temperature conditions. However, there are poor studies in natural convection from inclined cylinders. In this study, free convection heat transfer was examined experimentally from the outside surface of a cylinder for glycerol and water at various heat fluxes. The tests were performed at 10 different inclination angles of the cylinder, namely, φ = 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, and 90°, measured from the horizon. Our results indicated that the average Nusselt number reduces with the growth in the inclination of the cylinder to the horizon at the same heat flux, and the average Nusselt number enhanced with the growth in heat flux at the same angle. Also, the average Nusselt number of water is greater than that of glycerol. A new experimental model for predicting the average Nusselt number is suggested, which has a satisfactory accuracy for experimental data.

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Nowadays, root osseointegrated dental implants are used widely in dentistry mainly for replacement of the single missing tooth. The success rate of osseointegrated dental implants depends on different factors such as bone conditions; surgery insertion technique, loading history, and biomechanical interaction between jawbone and implant surface. In recent years, many studies have investigated design factors using finite element analysis with a concentration on major parameters such as diameter, pitch, and implant outlines in the distribution of stress in the bone-implant interface. There is still a need to understand the relationship and interaction of design factors individually with stress distribution to optimize implant structure. Therefore, the present study introduced a new dental implant and investigated the effect of design parameters on stress distribution. The finite element modeling was developed to facilitate the study with a comparison of design parameters. Boundary and loading conditions were implemented to simulate the natural situation of occlusal forces. Based on results, V-shape threads with maximum apex angle caused a high rate of micro-motion and high possibility of bone fracture. Low Von-Mises stress was associated with low bone growth stimulation. Besides, small fin threads did not integrate with cancellous bone and consequently lower stress accommodation. V-5 fin had no extraordinary performance in cancellous bone. Small surface areas of fins did not integrate with the surrounding bone and high-stress concentration occurred at the tail. These fins are recommended as threads replacement. It was concluded that the implant structure had less influence on stress distribution under horizontal loading.