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This paper presents a root cause analysis case study of defective Hall effect sensor devices. The study identified a complex failure mode caused by chip–package interaction, which has a similar signature to discharging defects such as ESDFOS (electrostatic discharge from outside to surface). However, the study revealed that the defect was induced by local mechanical force applied to IC structures due to the presence of large irregular shaped filler particles within the mold compound. Extensive failure analysis work was conducted to identify the failure mode, including the development of a new backside analysis strategy to preserve the mold compound during IC defect localization and screening. A combination of different failure analysis techniques was used, including CMP delayering, PFIB trenching, SEM PVC imaging and large area FIB cross-sectioning. The study found that the mold compound of the package caused thermo-mechanical strain onto the silica filler particle due to epoxy shrinkage during the molding process. Additionally, extra-large, irregularly shaped filler particles (called twin particles), located on top of the chip surface, can cause locally high compression stresses onto the IC layers, initiating cracks in the isolation layers under certain conditions forming a leakage path over the time. Thermo-mechanical finite element analysis was applied to verify the mechanical load condition for these large irregular shaped filler particles. As a result, an additional polyimide layer was introduced onto the IC to mitigate the mechanical stress of mold compound particles to avoid this failure mode. [ABSTRACT FROM AUTHOR]

The refractive index (RI) of biological tissues is a fundamental material parameter that characterizes how light interacts with tissues, making accurate measurement of RI crucial for biomedical diagnostics and environmental monitoring. A Janus sensor (JBS) is designed in this paper, and the photonic spin Hall effect (PSHE) is used to detect subtle changes in RI in biological tissues. The asymmetric arrangement of the dielectric layers breaks spatial parity symmetry, resulting in significantly different PSHE displacements during the forward and backward propagation of electromagnetic waves, thereby realizing the Janus effect. The designed JBS can detect the RI range of 1.3~1.55 RIU when electromagnetic waves are incident along the +z-axis, with a sensitivity of 96.29°/refractive index unit (RIU). In the reverse direction, blood glucose concentrations are identified by the JBS, achieving a sensitivity of 18.30°/RIU. Detecting different RI range from forward and backward scales not only overcomes the limitation that single-scale sensors can only detect a single RI range, but also provides new insights and applications for optical biological detection through high-sensitivity, label-free and non-contact detection. [ABSTRACT FROM AUTHOR]

Robot joints are the main structure for controlling the motion of the machine body, where the motion state of them directly affects the performance of the industrial robot. Due to the difficulty of obtaining the joint torque information of industrial robots, it is very hard to monitor the motion state of them. Based on the velocity and force driven by current of motors, we propose a novel Bayesian optimization framework to predict the joint motion state of industrial robot in this paper. Based on the temporal correlation of joint current and the correlation between the current and motion state of joint, we use the LSTM and BiLSTM to regressing prediction of the current and state of joint motor first. Then, the Bayesian optimization method is used to adjust the hyperparameters of our network, which realize the analysis of the joint motor current under different motion states and improve the accuracy of the prediction of joint motion states. Finally, we design the joint current acquisition platform of industrial robot based on Hall current sensors, which can collect joint currents without contact and generate experimental dataset. Comparing with the popular intelligent methods, the results show that our Bayesian optimization framework realizes a more accurate prediction of motion state for the four-axis industrial robot on the basis of contact-less current acquisition. [ABSTRACT FROM AUTHOR]

In this paper, a gallium nitride (GaN) magnetic Hall effect current sensor is simulated in 2D and 3D using the TCAD Sentaurus simulation toolbox. The model takes into account the piezoelectric polarization effect and the Shockley–Read–Hall (SRH) and Fermi–Dirac statistics for all simulations. The galvanic transport model of TCAD Sentaurus is used to model the Lorentz force and magnetic behaviour of the sensor. The current difference, total current, and sensitivity simulations are systematically calibrated against experimental data. The sensor is optimised using varying geometrical and biasing parameters for various ambient temperatures. This unintentionally doped ungated current sensor has enhanced sensitivity to 16.5 % T − 1 when reducing the spacing between the drains to 1 μm and increasing the source to drain spacing to 76 μm. It is demonstrated that the sensitivity degrades at 448 K (S = 12 %T−1), 373 K (S = 14.1 %T−1) compared to 300 K (S = 16.5 %T−1). The simulation results demonstrate a high sensitivity of GaN sensors at elevated temperatures, outperforming silicon counterparts. [ABSTRACT FROM AUTHOR]

Decades ago, Gurzhi proposed that if momentum-conserving collisions prevail among heat-carrying phonons in insulators and charge-carrying electrons in metals, hydrodynamic features will become detectable. In this paper, we will review the experimental evidence emerging in the last few years supporting this viewpoint and raising new questions. The focus of the paper will be bulk crystals without (or with a very dilute concentration of) mobile electrons and steady-state thermal transport. We also discuss the possible link between this field of investigation and other phenomena, such as the hybridization of phonon modes and the phonon thermal Hall effect. [ABSTRACT FROM AUTHOR]

Group-III nitrides have transformed solid-state lighting and are strategically positioned to revolutionize high-power and high-frequency electronics. To drive this development forward, a deep understanding of fundamental material properties, such as charge carrier behavior, is essential and can also unveil new and unforeseen applications. This underscores the necessity for novel characterization tools to study group-III nitride materials and devices. The optical Hall effect (OHE) emerges as a contactless method for exploring the transport and electronic properties of semiconductor materials, simultaneously offering insights into their dielectric function. This non-destructive technique employs spectroscopic ellipsometry at long wavelengths in the presence of a magnetic field and provides quantitative information on the charge carrier density, sign, mobility, and effective mass of individual layers in multilayer structures and bulk materials. In this paper, we explore the use of terahertz (THz) OHE to study the charge carrier properties in group-III nitride heterostructures and bulk material. Examples include graded AlGaN channel high-electron-mobility transistor (HEMT) structures for high-linearity devices, highlighting the different grading profiles and their impact on the two-dimensional electron gas (2DEG) properties. Next, we demonstrate the sensitivity of the THz OHE to distinguish the 2DEG anisotropic mobility parameters in N-polar GaN/AlGaN HEMTs and show that this anisotropy is induced by the step-like surface morphology. Finally, we present the temperature-dependent results on the charge carrier properties of 2DEG and bulk electrons in GaN with a focus on the effective mass parameter and review the effective mass parameters reported in the literature. These studies showcase the capabilities of the THz OHE for advancing the understanding and development of group-III materials and devices. [ABSTRACT FROM AUTHOR]

A recent systematic review and dose response meta-analysis, by Iamandii et al., considered the question "Does fluoride exposure affect thyroid function?" The authors concluded that, overall, exposure to high-fluoride drinking water appears to non-linearly affect thyroid function and increase TSH release in children, starting above a threshold of exposure, and to increase the risk of some thyroid diseases. The threshold of exposure for the TSH increase was 2 mg/L, or 2.5 mg/L when the studies with the best quality were considered. Although the lowest-observed-adverse-effect level (LOAEL) observed for TSH was a water fluoride level of approximately 2.5 mg/L, the changes in Total T3 and Total T4, a negative association, were present from very low levels, e.g. a water fluoride level of 0.2 mg/L and did not show a threshold effect. Fluoride in drinking water has been associated, by Hall et al., with an increased risk of hypothyroidism in pregnant women. A 0.5 mg/L increase in drinking water fluoride concentration was associated with a 1.65 (95% confidence interval [CI]: 1.04, 2.60) increased odds of primary hypothyroidism. Children born to women with primary hypothyroidism had lower FSIQ scores compared to children of euthyroid women, especially among boys (B coefficient : -8.42; 95%CI: -15.33, -1.50). The threshold, or point of departure, for fluoride in drinking water varies for different adverse effects such as the development of crippling skeletal fluorosis, dental fluorosis, an elevated TSH, a decreased Total T3 and Total T4, and impaired IQ in children. A recent paper by Grandjean et al. provides evidence that foetal toxicity can occur with a reduction in IQ when the maternal urinary fluoride is above 0.3 mg/L. A BMCL fluoride concentration in maternal urine during pregnancy of about 0.3 mg/L can be estimated to occur with a drinking water fluoride level of 0.24 mg/L, or approximately 0.3 mg/L. These findings suggest that, in order to protect the most vulnerable, a foetus in utero, public health attention should be given to elevated fluoride intakes during pregnancy, whether from drinking water, black tea, or other sources. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) half-metallic magnets are expected to achieve breakthroughs in the field of spintronics and quantum computation due to their 100% spin polarization and non-dissipative ballistic transport characteristics. However, the current availability of practical applications for these materials is limited. In this paper, a new 2D material NiVS6As2 is predicted based on density functional theory (DFT). It has a ferromagnetic ground state with a high Curie temperature, TC = 150 K and half-semi-metal (HSM) band structure protected by a structural symmetry degeneracy point on the Fermi surface, which can be controlled by an electric field and strain. When an out-of-plane electric field is applied, NiVS6As2 shows a Chern insulator with a quantum anomalous Hall (QAH) effect. These results expand the family of 2D magnetic semimetals, and provide new theoretical inspiration for understanding the protection of degenerate point symmetry. [ABSTRACT FROM AUTHOR]

In this paper, the effect of the rotation variable and other variables on the peristaltic flow of Sutterby fluid in an Inclined asymmetric channel containing a porous medium with heat transfer is examined. In the presence of rotation, mathematical modeling is developed using constitutive equations based on the model of Sutterby fluid. In flow analysis, assumptions such as long wavelength approximation and low Reynolds number are used. The resulting nonlinear ordinary differential equation was analytically solved using the perturbation method. The effects of the Grashof number, the Hartmann number, the Reynold number, the Froude number, the Hall parameter, the Darcy number, the magnetic field, the Sutterby fluid parameter, and heat transfer analysis on the stream function, and the pressure gradient are analyzed graphically. Utilizing MATHEMATICA software, numerical results were computed. It is discovered that the size of boluses decreases as some parameters increase, whereas the pressure gradient is directly proportional to the majority of parameters. [ABSTRACT FROM AUTHOR]

This paper investigates hall sensor signal unbalancing faults in sensored Brushless Direct Current (BLDC) motor drives and presents a fault effect minimization scheme for implementation in motor controller without any modification in system architecture, or core commutation method. In the proposed scheme detection, classification, and estimation of fault extent are carried out separately at the start of controller itself for subsequent corrections without involving issue of repetitive error estimation and finding valid reference signal separately for correcting inverter switching mistiming, as required in classical methods. The categorization part of scheme maps the faults with corresponding hall sensors. The proposed scheme is validated in MATLAB/Simulink model. It is tested on experimental test bench of controller and 1 kW BLDC motor of an electric rickshaw, along with another technique based on least square method (LSM) for performance comparison. Results show reduction of peak-to-peak value by 30% and ripple content by 50% in phase currents, and peak-to-peak reduction of 47% with 29% lesser ripple content in DC link current by using the presented scheme. The observed increment in efficiency is 0.8% and 2% in nominal torque/ampere at 30% load. At 100% load, increase of 2.2% efficiency and 9% nominal torque/ampere are observed. The increased memory loading of controller is estimated to be 1.25 times as compared to normal run without any correction scheme. Approximately 24% of this additional loading is utilized for repetitive calculations as compared to 63% in the other LSM based scheme, resulting in lesser run time loading of controller. The transient response with sudden load change shows better response with implementation of the proposed scheme in controller. [ABSTRACT FROM AUTHOR]

This research paper presents a novel mathematical model aimed at exploring practical applications in oscillating MHD generators and near-wall flows using Casson fluid. The purpose of this study is to develop a mathematical model that specifically addresses MHD free convective thermo-solutal transport within Casson fluid flow over a rotating vertical wall into a permeable medium. This research also considers factors like the Soret effect, radiative heat flux, first-order chemical reactions, and heat source/sink effects. To tackle this complex scenario, we apply the Laplace transform technique (LTT) to handle the transformed partial differential equations and their accompanying boundary conditions. The study investigated both ramped and isothermal wall temperature conditions and evaluated the influence of various parameters, including the Soret number, Hall current parameter, ramped wall temperature, and magnetic body force parameter. The computational analysis is carried out using MATLAB software. The research involves a comprehensive parametric analysis that thoroughly examines the impact of key emerging parameters on generalized velocity, temperature, and species concentration. The results reveal that magnetic, Casson, and rotating parameters all have a diminishing impact on the velocity profiles. The radiation parameter has a positive impact on temperature distribution, while an opposite trend is observed for the Prandtl number. Furthermore, an increase in the Soret number and chemical reaction parameter leads to a decrease in species concentration and solutal boundary layer thickness. The validation process includes comparisons with previous studies. Additionally, this study presents distributions of skin friction, Nusselt number, and Sherwood number. Notably, our findings reveal that a ramped wall temperature results in lower velocity magnitudes compared to the isothermal wall case. [ABSTRACT FROM AUTHOR]

This paper describes the results of a laboratory experiment on the sub-Alfvén expansion of a quasi-spherical laser plasma cloud into a vacuum magnetic field in the regime of nonmagnetized ions. The role of Hall fields and currents in the anomalously fast dynamics of the magnetic field during the collapse phase of a diamagnetic cavity is considered. Detailed spatial measurements of the azimuthal Hall fields configuration are demonstrated and their relationship to diamagnetic cavity collapse is determined. As a result of the experiment, data were obtained confirming the hypothesis about the transfer of the main magnetic field by the movement of electrons associated with Hall currents. [ABSTRACT FROM AUTHOR]

In the present investigation, the radiative MHD flow of an incompressible viscous electrically conducting non-Newtonian Casson hybrid nanofluidover an exponentially accelerated vertical porous surface has been considered. Under the influence of slip velocity in a rotating frame, it takes Hall and ion slip impacts into account. Water and ethylene glycol mixture is considered a base Casson fluid. A steady uniform magnetic field is applied under the postulation of a low magnetic Reynolds number. The ramped temperature and time-altering concentration at the surface are considered. First-order consistent chemical reaction and heat absorption are also regarded. Silver and Titania nanoparticles are disseminated in base fluid water and ethylene glycol combination should be formed by a hybrid nanofluid. The Laplace transformation technique is employed on the non-dimensional governing equations to ensure closed-form analytical solutions. The graphical representations scrutinize the effects of physical parameters on the significant flow characteristics. The expression for non-dimensional shear stress, heat transfer rate and mass transfer are also evaluated. They are tabulated with different variations in implanted parameters. For uniform and ramped wall temperatures, the resultant velocity grows by an increase in Hall and ion slip parameters. The resultant velocity increases by an increase in volume fractions of nanoparticles with uniform wall temperature, and a reverse effect is observed with ramped wall temperature. The temperature of Casson hybrid Ag-TiO2/WEG nanofluid is relatively superior to that of Casson Ag-WEG nanofluid. Species concentration of Casson hybrid Ag-TiO2/WEG nanofluid decreases with an increase in Schmidt number and chemical reaction parameters. The heat absorption increases the Nusselt number near the surface, while Ag and TiO2 nanoparticle volume fractions tend to lessen it. [ABSTRACT FROM AUTHOR]

The need for efficient heating and cooling systems in the automotive, aerospace, and chemical industries is driving the growth of heat transfer technologies. The hybrid nanomaterials are preferred over traditional nanofluids due to their exceptional thermal effectiveness. Keeping in mind the need for efficient cooling and heating systems, the thermal flow model based on the hybrid nanoparticles (GO-MoS2) immersed in hybrid base liquid $ {\textrm{C}_\textrm{2}}{\textrm{H}_\textrm{6}}{\textrm{O}_2} - {\textrm{H}_\textrm{2}}\textrm{O} $ C 2 H 6 O 2 − H 2 O is presented in this novel attempt by considering the influence of homogeneous–heterogeneous (H–H) reactions and Hall current with a magnetohydrodynamic effect induced by a vertical stretching sheet. A simplified examination is examined in the existence of solar radiation, mixed convection, and viscous dissipation. Suitable transformations provide the system of ordinary differential equations. Later, the solution is tackled numerically for the flow problems using the Runge–Kutta–Fehlberg process with a shooting technique. The role of influential parameters on involved distributions is discussed graphically and is explained logically in view of physical significance. Results reveal that, the thermal profile declines near convectively heated surface and upsurges away from the surface for incline in mixed convection parameter. An upsurge in the Biot number inclines the rate of heat transfer, but a contrary trend can be seen for escalating values of volume fraction. [ABSTRACT FROM AUTHOR]

Irreversible demagnetization processes in high-performance Fe-Nd-B magnets were investigated using a novel test rig. Designed to capture local magnetic field distributions and integral average magnetization in situ, the rig operates under field and temperature conditions similar to those found in electric motors. Validation against established techniques such as the hysteresisgraph and Hall mapper confirmed its accuracy. Furthermore, we observed the ability to detect even small variations of less than 2.5% in coercive field strength across the sample volume using field scans. The system significantly reduces measurement times from days to hours, enabling efficient in situ detection of magnetic field distributions during the whole demagnetization process. [ABSTRACT FROM AUTHOR]

We investigate emergent conductive phenomena triggered by collinear antiferromagnetic orderings. We show that an up-down-zero spin configuration in a triangle cluster leads to linear and nonlinear spin conductivities even without the relativistic spin–orbit coupling; the linear spin conductivity is Drude-type, while the nonlinear spin conductivity has Hall-type characterization. We demonstrate the emergence of both spin conductivities in a breathing kagome system consisting of a triangle cluster. The nonlinear spin conductivity becomes larger than the linear one when the Fermi level lies near the region where a small partial band gap opens. Our results indicate that collinear antiferromagnets with triangular geometry give rise to rich spin conductive phenomena. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales is the property of Academia Colombiana de Ciencias Exactas, Fisicas y Naturales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As we know, valley-Hall kink states or pseudospin helical edge states are excited by polarized-momentum-locking [left-handed circular polarization (LCP) and right-handed circular polarization (RCP)] because the valley-Hall kink modes or pseudospin polarized modes have intrinsic and local chirality, which is difficult for these states to achieve phase modulation. Here we theoretically design and study a compatible topological photonic system with coexistence of photonic quantum Hall phase and pseudospin Hall phase, which is composed of gyromagnetic photonic crystals with a deformed honeycomb lattice containing six cylinders. A typical kind of hybrid topological waveguide states with pseudospin-characteristic, magnetic field-dependent, and strong robustness against backscattering and perfect electric conductor (PEC) is realized in the present system. Furthermore, we re-design a structure with intersection-liked, achieve splitting for one-way pseudospin quantum Hall edge states by using phase modulation. Robustness of the one-way pseudospin-quantum Hall edge states in splitting has been demonstrated as well. Additionally, PEC inserted in transport channel brings optical path difference in waveguide transmission, which would influence splitting for hybrid topological waveguide states in phase difference modulation. This work not only provides a new way for manipulation (i.e., phase modulation) of hybrid topological waveguide states in compatible topological photonic system from distinct topological classes but also has potential in various applications, such as sensing, signal processing, and on-chip communications. [ABSTRACT FROM AUTHOR]

Using Challenging Minisatellite Payload (CHAMP) observations, responses of ionospheric radial current (IRC) in F‐layer to sawtooth substorms in different magnetic local times are investigated. The zonal wind effect alone cannot entirely explain the variability of the substorm time disturbance IRC. When substorms commence amid stable southward interplanetary magnetic field (IMF), it induces an eastward (westward) equatorial electric field in the daytime (nighttime). This electric field induces an equatorward (poleward) Hall current at low latitudes, consequently generating an upward (downward) perturbation in IRC. Conversely, substorms with varying IMF Bz, where IMF is southward but with a reduced magnitude or turned north after the onset, induce a westward (eastward) equatorial electric field in the daytime (nighttime). This electric field induces a poleward (equatorward) Hall current at low latitudes, consequently generating a downward (upward) disturbed IRC. Notably, this effect is primarily attributed to the varying IMF Bz rather than solely to substorm onset. Plain Language Summary: Substorms represent intense and dynamic disturbances within the Earth's magnetosphere, characterized by sudden bursts in auroral activity. The interplanetary magnetic field (IMF) stands out as an important factor in triggering substorms. Our work unveils for the first time that substorm accompanied by varying IMF Bz, where IMF is southward but with a reduced magnitude or turned north after the onset, and those during stable southward IMF periods, elicit diametrically contrasting effects on the ionospheric radial current (IRC) across all local time sectors. The IRC assumes a pivotal role in facilitating the energy exchange between the ionospheric E‐F layers, thereby exerting a profound influence on the ionospheric dynamics. Our work underscores a compelling correlation between the disturbed IRC and the penetration of the substorm electric field into the equatorial ionospheric E region under different IMF conditions. The study demonstrates the significant impact of different solar wind IMF conditions on the propagation of energy in Earth's space environment. Key Points: Initial observations of F‐layer radial current responses to substorms under different IMF conditionsSubstorm induces upward (downward) radial currents during the day (night) owing to Hall currents caused by disturbed electric fieldDaytime downward (nighttime upward) radial currents occur only in substorms with varying IMF Bz, due to overshielding electric field [ABSTRACT FROM AUTHOR]

Transition-metal doped topological insulators have been widely explored since the observation of quantum anomalous Hall effect (QAHE). Subsequently, the magnetic (Pb,Sn)(Te,Se) was predicted to possibly possess a high-temperature QAHE state. However, the fundamental understanding of Cr-doping-induced ferromagnetism in this system remains unclear. Here, we report the stable ferromagnetism in the high-crystalline Cr-doped SnTe films. Upon Cr doping, the magnetoconductance unveils a crossover from weak antilocalization to weak localization. Further increasing the Cr concentration to Cr0.17Sn0.83Te introduces a strong ferromagnetism with a Curie temperature of ~140 K. We detected a sizable spin moment ms = 2.28 ± 0.23 μB/Cr and a suppressed orbital moment ml = 0.02 μB/Cr. Cr dopants prefer to substitute the Sn sites and behave as divalent cations, as indicated by the experimental results and density function theory calculations. The controllable growth of magnetic SnTe thin films provides enlightenment towards the high-temperature QAHE in magnetic TCIs for the desired dissipationless transport in electronics. [ABSTRACT FROM AUTHOR]

The advancements in tactile sensor technology have found wide-ranging applications in robotic fields, resulting in remarkable achievements in object manipulation and overall human-machine interactions. However, the widespread availability of high-resolution tactile skins remains limited, due to the challenges of incorporating large-sized, robust sensing units and increased wiring complexity. One approach to achieve high-resolution and robust tactile skins is to integrate a limited number of sensor units (taxels) into a flexible surface material and leverage signal processing techniques to achieve super-resolution sensing. Here, we present a magnetic skin consisting of multi-direction magnetized flexible films and a contactless Hall sensor array. The key features of the proposed sensor include the specific magnetization arrangement, K-Nearest Neighbors (KNN) clustering algorithm and convolutional neural network (CNN) model for signal processing. Using only an array of 4*4 taxels, our magnetic skin is capable of achieving super-resolution perception over an area of 48400 mm2, with an average localization error of 1.2 mm. By employing neural network algorithms to decouple the multi-dimensional signals, the skin can achieve multi-point and multi-scale perception. We also demonstrate the promising potentials of the proposed sensor in intelligent control, by simultaneously controlling two vehicles with trajectory mapping on the magnetic skin. [ABSTRACT FROM AUTHOR]

Active fluids composed of constituents that are constantly driven away from thermal equilibrium can support spontaneous currents and can be engineered to have unconventional transport properties. Here, we report the emergence of (meta)stable traveling bands in computer simulations of aligning circle swimmers. These bands are different from polar flocks and, through coupling phase with mass transport, induce a bulk particle current with a component perpendicular to the propagation direction, thus giving rise to a collective Hall (or Magnus) effect. Traveling bands require sufficiently small orbits and undergo a discontinuous transition into a synchronized state with transient polar clusters for large orbital radii. Within a minimal hydrodynamic theory, we show that the bands can be understood as nondispersive soliton solutions fully accounting for the numerically observed properties. [ABSTRACT FROM AUTHOR]

We have designed a high-resolution magnetic field imaging system using 256 unpackaged Hall elements. These unpackaged Hall elements are arranged in a Hall linear array, and the distance between adjacent elements reaches 255 µm. The sensitivity of the unpackaged Hall element array can be adjusted using a computer to measure magnetic environments with different magnetic field strengths. High-resolution magnetic field images of 256 × 256 pixels can be generated by moving the array using the X–Y axis motorized rail. This spatial resolution can reach 99.61 pixels per inch (ppi). This rail allows for the spatial resolution of the system to be further increased to 199.22 ppi by using a special movement route. In the experiments, we employ this system to image magnetized metal scissors, and the result displays the structural features of the scissor surface. We also detected the magnetic suction wireless charging coil inside an Apple phone. The image obtained shows the shape of the coil and the gap between the magnets. The high-resolution magnetic imaging system displays the magnetic characteristics of the sample very well and easily obtains information about small-shaped structures and defects on the sample surface. This provides the system with potential in several fields such as quality inspection, security, biomedicine, and detection imaging. [ABSTRACT FROM AUTHOR]

With the emergence of RISC-V architecture in embedded devices, its inherent low-power features have propelled its extensive adoption across various industrial settings. Displacement sensors leveraging Hall sensors and magnetic flux measurement present notable benefits including cost-effectiveness and compact design. This study undertakes the porting of Hall sensors onto RISC-V architecture embedded devices, validating their functionality within displacement sensors. Empirical investigations substantiate that the ported system consistently delivers comparable outcomes to those obtained from x86 architecture systems employing PM-MFM methods, affirming its reliability and performance in practical applications. [ABSTRACT FROM AUTHOR]

A motor resistance parameter identification scheme was proposed for the speed prediction of a direct-torque-controlled (DTC) induction motor (IM) drive. The DTC IM drive was established on the basis of the stator's current and flux, with the stator current acquired from an IM using the Hall effect current sensor. Rotor speed prediction was achieved using the electromagnetic torque and rotor flux. The stator resistance parameter identification scheme was developed using the model reference adaptive system based on the motor's active power, and the adaptation mechanism was designed using the modified particle swarm optimization algorithm. The MATLAB\Simulink® toolbox was utilized to simulate this system, and all the control algorithms were realized using a TI DSP 6713 and F2812 micro-control card to validate this approach. Simulation and experimental results confirmed the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

We consider a matching problem in a bipartite graph G = (A ∪ B , E) where vertices in A rank their neighbors in a strict order of preference while vertices in B are allowed to have weak rankings, i.e., ties are allowed in their rankings. Stable matchings always exist in G and are easy to find, however popular matchings need not exist in G and it is NP-complete to decide if one exists. This motivates the "approximately popular" matching problem. A well-known measure of approximate popularity is low unpopularity factor. We show that when each tie in G has length at most k, there always exists a stable matching whose unpopularity factor is at most k and such a matching can be computed in polynomial time. Thus when ties have bounded length, there always exists a near-popular stable matching. This can be considered to be a generalization of Gärdenfors' result (1975) which showed that when rankings are strict, every stable matching is popular. We then extend our result to the hospitals/residents setting, i.e., vertices in B have capacities. There are several applications where the size of the matching is its most important attribute. When ties are one-sided and of length at most k, we show a polynomial time algorithm to find a maximum matching whose unpopularity factor within the set of maximum matchings is at most 2k. [ABSTRACT FROM AUTHOR]

Copyright of Iraqi Journal of Science is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ionospheric electrodynamics is a problem of mechanical stress balance mediated by electromagnetic forces. Joule heating (the total rate of frictional heating of thermospheric gases and ionospheric plasma) and ionospheric Hall and Pedersen conductances comprise three of the most basic descriptors of this problem. More than half a century after identification of their central role in ionospheric electrodynamics, several important questions about these quantities, including the degree to which they exhibit hemispheric symmetry under reversal of the sign of dipole tilt and the sign of the y component of the interplanetary magnetic field (so-called "mirror symmetry"), remain unanswered. While global estimates of these key parameters can be obtained by combining existing empirical models, one often encounters some frustrating sources of uncertainty: the measurements from which such models are derived, usually magnetic field and electric field or ion drift measurements, are typically measured separately and do not necessarily align. The models to be combined moreover often use different input parameters, different assumptions about hemispheric symmetry, and/or different coordinate systems. We eliminate these sources of uncertainty in model predictions of electromagnetic work J⋅E (in general not equal to Joule heating ηJ2) and ionospheric conductances by combining two new empirical models of the high-latitude ionospheric electric potential and ionospheric currents that are derived in a mutually consistent fashion: these models do not assume any form of symmetry between the two hemispheres; are based on Apex magnetic coordinates (denoted Apex), spherical harmonics, and the same model input parameters; and are derived exclusively from convection and magnetic field measurements made by the Swarm and CHAMP satellites. The model source code is open source and publicly available. Comparison of high-latitude distributions of electromagnetic work in each hemisphere as functions of dipole tilt and interplanetary magnetic field clock angle indicates that the typical assumption of mirror symmetry is largely justified. Model predictions of ionospheric Hall and Pedersen conductances exhibit a degree of symmetry, but clearly asymmetric responses to dipole tilt and solar wind driving conditions are also identified. The distinction between electromagnetic work and Joule heating allows us to identify where and under what conditions the assumption that the neutral wind corotates with the Earth is not likely to be physically consistent with predicted Hall and Pedersen conductances. [ABSTRACT FROM AUTHOR]

Hybrid magnetic tunnel junction (MTJ)/CMOS circuits based on the computation-in-memory (CIM) architecture are contemplated as the future generation of digital integrated circuits. It overcomes the limitations of von-Neumann architecture by offering solutions to problems such as memory wall and standby power dissipation. In this work, we have developed hybrid logic gates, such as AND/NAND, OR/NOR, and XOR/XNOR, for CIM architecture by integrating three terminal spin-Hall effect assisted spin transfer torque (SHE + STT) MTJs with standard CMOS. To write the MTJs an auto-write-stopping (AWS) circuit is adopted, whereas to perform the logic operations and produce the corresponding outputs, an improved sense amplifier circuit (ISA) is employed. All the hybrid logic gates are investigated for key performance indicators such as power, delay, device count, and power delay product (PDP). The results are compared with their conventional counterparts. The comparison reveals that the ISA + AWS-based hybrid gates dissipate 50.52% lower total power. The worst-case read delay of ISA + AWS hybrid AND/NAND, OR/NOR, and XOR/XNOR gates are 27.41%, 13.4%, and 21.28% lower. Meanwhile, the reduction of read PDP (write PDP) is 47.64% (37.09%), 25.78% (36.29%), and 39.31% (35.48%) observed with ISA + AWS hybrid AND/NAND, OR/NOR, and XOR/XNOR gates in comparison with the conventional counterparts. Hence the ISA + AWS gates are superior in terms of total power dissipation, worst read delay, and read/write PDP. Further, we have conducted Monte-Carlo simulations on all the logic circuits to study the parameter variations during fabrication. [ABSTRACT FROM AUTHOR]