Experimental study of combustion in a double-layer burner packed with alumina pellets of different diameters

BACKGROUND: Prefabricated zirconium upgrading systems were examined to satisfy aesthetic needs in endodontically treated teeth. Endodontically treated teeth, together with non-metallic posts and superstructure, are substructures that enable the production of prosthetic structures that will allow aesthetics, resulting from normal light transmission. To investigate and analyse the retention of zirconium post systems cemented with RelyX Unicem 2 Automix (RLX) cement with Pull-out test. AIM: To examine the retention of zirconium post systems, cemented with Multi-Link Automix (MLA) cement and RelyX Unicem 2 Automix (RLX) cement with Pull-out test. MATERIAL AND METHODS: In this study were used, 120 post systems of the company ZIRIX NORDIN - Switzerland, with different diameters d1 = 1.2, were used: d2 = 1.35, d3 = 1.5, and two types of resin cements: Multilink Automix-Ivoclar (MLA), and RelyX Unicem 2 Automix (RLX) - 3 M ESPE. RESULTS: The analysis of the extraction force in newtons (N) zirconium post systems of Multilink Automix cement according to subgroups of three diameters is consequently 481.3 ± 1.9 vs 462.9 ± 4.5 vs 454.2 ± 2.2. The analysis of the extraction strength in the newtons (N) zirconium post systems of RelyX Unicem 2 Automix cement in the entire sample is 577.9 ± 6.1 N. CONCLUSION: The largest diameter of the posts significantly increases the resistance of fractures compared to the smaller two diameters used in the experimental study.

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Numerical Simulation of Vortex-Induced Vibration of Two Tandem Cylinders With Different Diameters Under Uniform Flow

Volume 8: CFD and FSI ◽

10.1115/omae2020-18607 ◽

2020 ◽

Author(s):

Xuepeng Fu ◽

Yuwang Xu ◽

Mengmeng Zhang ◽

Haojie Ren ◽

Bing Zhao ◽

...

Keyword(s):

Numerical Simulation ◽

Experimental Study ◽

Stokes Equations ◽

Circular Cylinders ◽

Navier Stokes ◽

Flexible Cylinder ◽

Single Cylinder ◽

Frequency Capture ◽

Tandem Cylinders ◽

Different Diameters

Abstract Vortex-induced vibrations (VIV) of two elastically mounted circular cylinders with different diameters in tandem arrangement are investigated in a two-dimensional (2D) numerical simulation. The fluid domain is simulated by solving 2D Reynold-Averaged Navier-Stokes equations. Meanwhile, the VIV response of the structures is obtained by solving the motion equation using the 4th Runge-Kutta method. The parameters of the cylinders are designed according to an experimental study of flexible risers. Simulation of an elastically mounted single cylinder is firstly carried out and compared with published experimental results to verify the method utilized in the paper. The results of single cylinder show the response frequencies of the bluff cylinders and the flexible cylinder are comparable. In the simulation of the tandem cylinders, a “frequency capture” phenomenon that the oscillation frequencies of downstream cylinder are locked on to that of the up-stream one although they are with different diameters is observed. It also occurs in the experimental study of flexible cylinders. The mechanism behind is analyzed in the paper.

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