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Large-scale phenotyping of tip-growing cells such as pollen tubes has hitherto been limited to very crude parameters such as germination percentage and velocity of growth. To enable efficient and high-throughput execution of more sophisticated assays, an experimental platform, the TipChip, was developed based on microfluidic and microelectromechanical systems (MEMS) technology. The device allows positioning of pollen grains or fungal spores at the entrances of serially arranged microchannels equipped with microscopic experimental set-ups. The tip-growing cells (pollen tubes, filamentous yeast or fungal hyphae) may be exposed to chemical gradients, microstructural features, integrated biosensors or directional triggers within the modular microchannels. The device is compatible with Nomarski optics and fluorescence microscopy. Using this platform, we were able to answer several outstanding questions on pollen tube growth. We established that, unlike root hairs and fungal hyphae, pollen tubes do not have a directional memory. Furthermore, pollen tubes were found to be able to elongate in air, raising the question of how and where water is taken up by the cell. The platform opens new avenues for more efficient experimentation and large-scale phenotyping of tip-growing cells under precisely controlled, reproducible conditions.

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This article presents a novel Direct Field-Oriented Control (DFOC) strategy for Fault-Tolerant Control (FTC) of wye-connected 3-Phase Induction Machine (3-PIM) drives under the stator winding open-phase failure. In the proposed control strategy, instead of flux measurement, an Extended Kalman Filter (EKF) for flux estimation is used. The introduced controller with minor modifications can be used during normal and stator winding open-phase failure conditions. With the proposed DFOC system, the speed and torque pulsations that normally happen during the open-phase failure can be reduced. The performances of the proposed EKF-based DFOC strategy and the conventional control strategy for a faulted machine using simulations and experiments under different operation conditions are compared. Simulation and experimental results demonstrated an important improvement in speed and torque pulsations through this type of fault. Results also confirmed the superiority of the proposed EKF-based DFOC scheme over the conventional control scheme to balance the faulted machine phase currents.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

The present study aims to propose an indirect field-oriented control (IFOC) strategy for star-connected three-phase induction machine (SCTPIM) drives against singlephase open-circuit fault. In the proposed IFOC method, transformation matrices (TMs) are applied to the faulty SCTPIM equations. Based on the results, the asymmetrical equations of the faulty SCTPIM can be transformed into symmetrical equations by using these matrices. The symmetrical equations have structures which are similar to healthy SCTPIM equations. Thus, a midfield IFOC strategy could be shared during both normal and open-phase fault operations. The performance of the proposed control system was confirmed based on the simulations and experiments for a vector controlled 0.75 kW SCTPIM drive. The results confirmed the effectiveness of the introduced controller in the speed and torque ripples decreasing of the faulty SCTPIM and eliminating the unbalances in the faulty SCTPIM currents.

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