No abstract

The biomechanical effects on cervical vertebral columns (C1-C7) during mastication were calculated using a three-dimensional (3D) finite element method. To verify the biomechanical influences of vertical occlusal alteration to the cervical column, three finite element models (FEM) showing a normal (model A), a steep (model B), and a flat occlusal plane (model C) were constructed. The occlusal stress distribution showed various patterns for the three models; the stress extended to the anterior area as the occlusal plane became steeper. The plots of the stresses on the mid sagittal section of the cervical columns showed different patterns for the three models; the stress converged at the odontoid process in models A and B, whereas the stresses at C7 in model B tended to decrease compared with model A. Concentrated stress was observed at C5 in model C, supporting the hypothesis that vertical occlusal alteration could influence stress distribution in the cervical columns.

No abstract

No abstract

Thermal Knudsen forces arise in microsystem in presence of a thermal gradient and a rarefied gas environment due to the non-equilibrium energy exchange between gas molecules and solid surfaces. Knudsen force can be used as an alternative actuation mechanism for microactuators. The purpose of this work is to design and optimize a Knudsen force actuated microbeam using modeling and simulation. The microbeam is heated by an external heat source that causes a thermal gradient between the beam and substrate. The characteristic domain size is small enough so that the rarefied gap effect is present. The study focuses on three major components that influence the Knudsen force significantly, including geometry of microbeam, external heat input to the system, and the radiometric effects generated by Peltier thermoelectric device. A Boltzmann-ESBGK model is implemented to simulate the rarefied gas flow and a continuous Fourier heat transfer model is used to solve the beam temperature field generated by the external heat source, and the fluid and solid regions are coupled using an effective heat convection interface condition.