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Heavy cold ions at Mars are gravitationally bound to the planet unless some process provides energy to them. Observations show that cold (<20 eV) and dense (∼>1 cm−3) O+/O2+ ions with bulk velocities equal to energies ∼1 keV can reach deep into the nightside Martian magnetosheath. These ions are co‐located with a change of the sign of the sunward component of the magnetic field. This magnetic field topology implies the persistence of a localized planetary ions escape channel associated with draped magnetic field lines that are convecting tailward. The observed ion populations propagate approximately in the same direction as surrounding magnetosheath flow and are likely to be almost unheated ionospheric ions from low altitudes. The paper discusses planetary ion energization via Hall electric field originated from ions and electron separation associated with magnetic field curvature. Plain Language Summary: In‐situ observations above the nightside of Mars show the presence of localized dense planetary ion fluxes at altitudes exceeding 2,000 km and escaping from the planet at high energies, comparable to that of the solar wind. These fluxes are accompanied by the reversal of sunward component of magnetic field. Unlike most atmospheric escape channels, the reported phenomenon is characterized by an increase in heavy to light ions density ratio with the distance from the planet at the observed altitudes up to nearly 5,000 km, as well as an increase in overall plasma number density inside this escape channel relative to the ambient sheath environment. This behavior is consistent with acceleration process initiated by a bent magnetic flux tube. Key Points: Ions of different species gain similar energies in the Martian magnetosheath by Hall electric fields associated with magnetic curvatureA high concentration of ionospheric ions correlates with a near void of shocked solar wind protons and a magnetic field reversalNumber density at the reversal increases with distance from Mars in comparison to the surrounding sheath at least till two Martian radii [ABSTRACT FROM AUTHOR]

Tunability of topological photonic structures opens a new avenue for photonics research. The rich physical characteristics of the topological photonics have great significance in practical implementations. In this paper, multi‐type topological states are demonstrated in higher‐order photonic topological insulators based on Kagome metal lattices. By stretching or rotating Kagome metal lattices, two types of topological insulators are obtained, and multi‐type topological states are observed. By stretching Kagome metal lattices, a 1D topological edge state and two types of higher‐order topological corner states (corresponding to a traditional higher‐order topological corner state based on nearest‐neighbor coupling and a new higher‐order corner state caused by long‐range interactions) are obtained in a classical quantization of dipole moments higher‐order topological insulators. By rotating Kagome metal lattices, dual‐band higher‐order valley‐Hall topological insulators are achieved with nodal ring degeneracy. Odd‐type and even‐type topological states are obtained. Achieving reconfigurable, multi‐type, and multi‐band topological insulators by using a single structural unit provides interesting insights into topological photonics and provides an unconventional approach to explore photonic systems and condensed matter physics. [ABSTRACT FROM AUTHOR]

Calibration is the backbone of any sensor and measurement philosophy. The conventional calibration techniques for electrical parameter measurement using nonlinear sensors are affected by the repeating analogue signals and lead to errors in measurement. This research paper investigates different regression‐based mathematical models to calibrate the Hall sensor for measuring RMS and the fundamental frequency. The novelty of this research work lies in the feature‐based input modelling to measure RMS current and frequency with an error of 3.37e‐12% and 7.61e‐9%, respectively. The conventional Fourier transform method is compared with six different bio‐inspired metaheuristic algorithms to estimate the frequency components of the analogue signal received from the measurement setup. Apart from the conventional sine waveforms, this paper investigates sawtooth and square waveforms as the periodic signals for determining the frequency components. The results from the comparison study show that the Whale Optimization Algorithm exhibits 1.25% lesser error whilst predicting the features in measured frequency components. Apart from this, the paper identifies a unique combination of features that effectively measures the instantaneous electrical parameter with RMSE, NRMSE, and R2 value of 158.8, 0.51, and 0.44, respectively. Experimentally it is found that the decision tree and random forest regression models calibrate the Hall sensor with 93% less error than their linear and polynomial counterparts. [ABSTRACT FROM AUTHOR]

Summary: Electronic commutator in Brushless DC motor (BLDC) drives decides the sequence of driving current through the stator windings based on the rotor position sensed by the three Hall position sensors. If any fault occurs in the Hall sensors, it will result in a faulty driving sequence of rotors and the motor will stall. This paper investigates an artificial intelligence‐based Fault Diagnosis and Compensation (FDC) system for correcting up to two position sensor failures in trapezoidal back EMF BLDC motor drives. The proposed fault‐tolerant system is a simple, fast, and efficient method to diagnose and reconstruct the commutation signals using the existing processor‐based commutator arrangements. An Artificial Intelligence algorithm is developed to estimate the correct switching sequence in the absence of up to two Hall sensor signals while the motor is running. This supervised learning network is advantageous as it is added as an additional control algorithm with the existing control algorithm for BLDC motor. The simulation and hardware results showcase the effective performance of the proposed algorithm for different Hall sensor fault conditions. [ABSTRACT FROM AUTHOR]

The anomalous Hall effect (AHE) is a quantum coherent transport phenomenon that conventionally vanishes at elevated temperatures because ofthermal dephasing. Therefore, it is puzzling that the AHE can survive in heavy metal (HM)/antiferromagnetic (AFM) insulator (AFMI) heterostructures at high temperatures yet disappears at low temperatures. In this paper, an unconventional high-temperature AHE in HM/AFMI is observed only around the Néel temperature of AFM, with large anomalous Hall resistivity up to 40 nQ cm is reported. This mechanism is attributed to the emergence of a noncollinear AFM spin texture with a non-zero net topological charge. Atomistic spin dynamics simulation shows that such a unique spin texture can be stabilized by the subtle interplay among the collinear AFM exchange coupling, interfacial Dyzaloshinski-Moriya interaction, thermal fluctuation, and bias magnetic field. [ABSTRACT FROM AUTHOR]

It is difficult to separate Luer lock adapters during the external ventricular drainage (EVD) since they are often connected by a threaded connection, and the infusion needle put into the patient's body gets pulled out when extubation occurs unexpectedly. The paper described a new magnetic connection assembly made up of ring magnetic permanents and a Hall sensor that could be used to replace Luer lock adapters for quicker disconnection and reconnection of the drainage catheter. For the design and analysis of the device, the finite element method magnetics (FEMM) was used to estimate the size of magnetic permanents and the best detection site of the Hall sensor for detecting whether the magnetic permanents were closely attracted and/or pulled apart. Then an experiment was conducted to confirm our findings. Both simulation and experiment revealed that a pair of hollow cylindrical magnetic permanents, each with height 10 mm, outer diameter 8 mm, and inner diameter 4 mm, could achieve the same force as the Luer lock adapters held, and that the best Hall sensor detection position was in the middle of the permanent magnets, with a radial distance of about 2 mm. [ABSTRACT FROM AUTHOR]

Accurate position signals are essential for a vector control system. To obtain accurate position signals, high‐precision position sensors such as optical encoder and resolver are employed. However, they are usually restricted by the environmental condition and cost. Linear Hall‐effect sensors, possessing tiny size, light weight and low cost, are usually used to detect position signals. However, the position signals detected by linear Hall‐effect sensors in low cost conditions always contain a large part of high‐order harmonics, which will decrease the validity and reliability of sensor measurement. In this paper, to eliminate the influence of harmonics, a short‐distance harmonic suppression method without any low‐pass filter is proposed. The proposed method utilises three linear Hall‐effect sensors displaced a certain electrical angle to dissolve the position signal. Through simulation analysis and experimental verification, the proposed method has been proven to be effective in suppressing the third‐order and fifth‐order harmonics. [ABSTRACT FROM AUTHOR]