Substance Flow Analysis (SFA) is mainly used to quantify ows and stocks of a particular substance distributed in a nite ecosystem. It can also be used to help decision-makers select the best strategy to implement resource allocation and management. This study focused on tantalum ow in Taiwan in 2013, speci cally as tantalum capacitors, powder, and waste products. Tantalum, a rare metal that has a lot of potential, especially in the electronics industry, is not locally produced in Taiwan; so an SFA is vital to monitor supply, demand, and accumulation. Best estimates were done in coordination with Taiwan companies and government agencies, namely: Ministry of Economic Affairs; Ministry of Finance; Customs Department; and Environmental Protection Administration. In 2013, Taiwan imported a total of 340,355 kg of tantalum; 84.5% of this remained in Taiwan either as electronic products or as raw materials, while the rest were exported.
In this paper a multiphysics simulation of nanotube based nano-electromechanical systems is reported. Assuming continuum mechanics, the nonlinear deformation of the nanotube is simulated using reduced order modeling method. In particular, we study singly and doubly clamped nanotubes under electrostatic actuation. The simulation emphasizes the prediction of the pull-in voltage of the device, a key design parameter. Moreover, the nonlinear behavior associated with finite kinematics (i.e., large deformations), neglected in previous studies, are investigated in detail. The multiphysics simulation results agree well with the theoretical predictions verifying that the numerical model is valid. The results show that nonlinear kinematics results in an important increase in the pull-in voltage of doubly clamped nanotube devices, but that it is negligible in the case of singly clamped devices. These models provide a guide on the effect of the various geometrical variables and insight into the design of novel devices.
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