Self-powered mobile sensor for in-pipe potable water quality monitoring

Traditional stationary sensors for potable-water quality monitoring in a wireless sensor network format allow for continuous data collection and transfer. These stationary sensors have played a key role in reporting contamination events in order to secure public health. We are developing a self-powered mobile sensor that can move with the water flow, allowing real-time detection of contamination in water distribution pipes, with a higher temporal resolution. Functionality of the mobile sensor was tested for detecting and monitoring pH, Ca2+, Mg2+, HCO3-/CO32-, NH4+, and Clions. Moreover, energy harvest and wireless data transmission capabilities are being designed for the mobile sensor

Minimization of Field Enhancement in Multilayer Capacitors

Evidence has shown that capacitor failure can often be attributed to field enhancement that occurs near electrode tips. In this research, methods to minimize field enhancement have been investigated using a combination of finite element analysis and an evolutionary algorithm. Specifically, the two methods considered are (1) to modify the electrode structure and (2) to adjust the resistivity in the dielectric region surrounding the tip. Optimal electrode structures and resistivity profiles have been derived that result in a significant reduction of field enhancement. Interestingly, it is predicted that adjustment of resistivity can yield a much greater reduction with a relatively minor increase in conduction loss

A comparison of nodal- and mesh-based magnetic equivalent circuit models

The magnetic equivalent circuit (MEC) technique is a powerful analysis and design tool that combines relative accuracy with moderate computational effort. In this paper, a nodal-based MEC formulation and a mesh-based MEC formulation of a magnetic system are compared. The Newton-Raphson algorithm is used to solve the algebraic system, and to draw conclusions about the computational efficiency of the two formulations under linear and nonlinear operation. Although the two formulations exhibit similar performance under linear operating conditions, the performance of the mesh-based model is significantly better than that of the nodal-based model under nonlinear operation