ABSTRACT
Hybrid renewable energy systems (HRES) are a nexus of various renewable energy sources that have been proposed as a solution to circumvent various issues of renewable energy systems when installed in isolation. During the operation of an HRES, efficient demand-side management of energy and real-time power trading requires accurate estimation of real-time variables for each sub-component. Generally, these variables are corrupted by measurement errors. To address this issue, in this study, we present various frameworks for reconciliation strategies that can be used to rectify the inconsistencies in the sensor measurements of HRES. Specifically, in this study, we evaluate the efficacy of various static and dynamic reconciliation strategies such as Regularized Particle filter (RPF), Ensemble Kalman filter (EnKF), and Extended Kalman filter (EKF) of a candidate HRES system with a solar panel, a fuel cell, and an electrolyzer. Proposed frameworks are evaluated using various simulation-based validation studies. To this end, we have considered different operational scenarios, namely, (i) single-rate sampling, (ii) multi-rate sampling, and (iii) sensor outage, to make the study comprehensive. Simulation results indicate that RPF yields the best estimation accuracy for all three operational scenarios with a performance improvement of 75% from EKF and by 50% from EnKF, with only a fractional increment in computational time.
ABSTRACT
Wireless powering could enable the long-term operation of advanced bioelectronic devices within the human body. Although both enhanced powering depth and device miniaturization can be achieved by shaping the field pattern within the body, existing electromagnetic structures do not provide the spatial phase control required to synthesize such patterns. Here, we describe the design and operation of conformal electromagnetic structures, termed phased surfaces, that interface with non-planar body surfaces and optimally modulate the phase response to enhance the performance of wireless powering. We demonstrate that the phased surfaces can wirelessly transfer energy across anatomically heterogeneous tissues in large animal models, powering miniaturized semiconductor devices (<12 mm3) deep within the body (>4 cm). As an illustration of in vivo operation, we wirelessly regulated cardiac rhythm by powering miniaturized stimulators at multiple endocardial sites in a porcine animal model.
ABSTRACT
Myelin formation has been identified as a modulator of neural plasticity. New tools are required to investigate the mechanisms by which environmental inputs and neural activity regulate myelination patterns. In this study, we demonstrate a microfluidic compartmentalized culture system with integrated electrical stimulation capabilities that can induce neural activity by whole cell and focal stimulation. A set of electric field simulations was performed to confirm spatial restriction of the electrical input in the compartmentalized culture system. We further demonstrate that electrode localization is a key consideration for generating uniform the stimulation of neuron and oligodendrocytes within the compartments. Using three configurations of the electrodes we tested the effects of subcellular activation of neural activity on distal axon myelination with oligodendrocytes. We further investigated if oligodendrocytes have to be exposed to the electrical field to induce axon myelination. An isolated stimulation of cell bodies and proximal axons had the same effect as an isolated stimulation of distal axons co-cultured with oligodendrocytes, and the two modes had a non-different result than whole cell stimulation. Our platform enabled the demonstration that electrical stimulation enhances oligodendrocyte maturation and myelin formation independent of the input localization and oligodendrocyte exposure to the electrical field.
