An efficient multi-time step FEM–SFEM iterative coupling procedure for elastic–acoustic interaction problems

An iterative coupling methodology between the Finite Element Method (FEM) and the Spectral Finite Element Method (SFEM) for the modeling of coupled elastic-acoustic problems in the time domain is presented here. Since the iterative coupling procedure allows the use of a nonconforming mesh at the interface between the subdomains, the difference in the element sizes concerning the FEM and SFEM is handled in a straightforward and efficient manner, thereby retaining all the advantages of the SFEM. By means of the HHT time integration method, controllable numerical damping can be introduced in one of the subdomains, increasing the robustness of the method and improving the accuracy of the results; besides, independent time-step sizes can be considered within each subdomain, resulting in a more efficient algorithm. In this work, a modification in the subcycling procedure is proposed, ensuring not only an efficient and accurate methodology but also avoiding the computation of a relaxation parameter. Numerical simulations are presented in order to illustrate the accuracy and potential of the proposed methodology.CAPES, UFJF, UFSJ, FAPEMIG and CNP

Work-related musculoskeletal pain among Lebanese dentists: An epidemiological study

Introduction: The aim of this study was to evaluate the prevalence of musculoskeletal disorders and identify their associated factors among a group of Lebanese dentists.Materials and Methods: A total of 314 Lebanese, dentists completed an anonymous questionnaire that focused on occupational health problems. This study was approved by the ethics committee of Saint-Joseph University of Beirut, Lebanon. The statistical analyses were performed using SPSS for windows. The alpha error was set to 0.05.Results: The mean age of the participants was 39.2 (±11.66) years. The results showed that 61.5% of the surveyed dentists complained of spinal pain: 31.6% of cervical pain, 22.3% of lumbar pain and 13.0% of dorsal pain. Moreover, the pain was continuous in 20.7% and, occasional in 65.8%. Our statistics showed that 7.6% had a problem with the carpal tunnel. A total of 22.3% suffered from tendinitis and 9.2% from arthritis of shoulder, elbow, wrist and hand. The frequency of headaches was 30.6%. Concerning sports activity, 49.7% practiced it occasionally and 3.6% did so frequently.Conclusions: The occurrence of musculoskeletal pain in the upper extremities is a serious concern that affects Lebanese dentists. Most of them often complained of tendinitis and headaches because they do not practice sports; thus, encouraging them to practice sports may reduce or solve such health problems. Issuing brochures that include exercises to perform and hiring trained assistants could help reduce the risk of musculoskeletal disorders. Finally, these occupational health problems should be highlighted at all clinical and research symposia to increase awareness.Keywords: Epidemiology, Lebanese dentist, musculoskeletal disorders, occupational diseas