Applied Mechanics and Materials Vol. 461

Abstract: A fluid dynamics model of electrolyte in mircroflow inspired by hemodynamic model of aortic is proposed and applied in the self-noise analysis of four-electrode microflow-electrochemical accelerometer. Three-dimensional finite element model is established and invested through numerical simulation, the variety of geometrical parameters on different location of electrode and varied time are considered, which can affect the microflow-electrochemical accelerometers self-noise. The result of numerical simulation indicates that, self-noise is related to electrode configuration as well as electrode geometrical parameters. In particular, convection-induced self-noise is correlated to variety of viscosity, and thermohydrodynamic self-noise is correlated to variety of diameter. Such a fluid dynamics model of electrolyte inspired by thermodynamics model can be also used for optimization of the self-noise.

Abstract: Introduction: An en-masse retraction with mini implant (MI) anchorage may be associated with unwanted intrusion/extrusion and uncontrolled tipping of anterior teeth. An optimum combination of MIs and hooks heights is required for proper treatment results. Materials and Methods: Maxillary finite element models were constructed from a cone beam CT scan of a patient’s orofacial region. The initial tooth displacement at 200g force with 0.019 × 0.025-in stainless steel working archwires engaged in 0.022 brackets slot was assessed. The three-dimensional displacement was examined at various MI and AAH heights. Results: The lower MI position caused extrusion of the central incisors, but the teeth were intruded at higher (6- and 8-mm) MI heights. While the shorter (2- and 4-mm) hooks extruded the central incisors, the higher (6- and 8-mm) intruded the teeth. The higher MI and hooks reduced the palatal tipping of central incisors. The distobucal cusp of the first molar was intruded, while the mesiobucal cusp was extruded in all models: Nonetheless, the shorter hooks and low MI had small molar tipping effects. Conclusions: The higher MIs caused intrusion and less palatal tipping of the central incisors crowns. The increase in hook height resulted into extrusion and reduction in palatal tipping of the central incisors crowns.