Onset of double-diffusive convection in an inclined bidispersive porous layer with magnetic field effect and uniform internal heat source

Heterointerface-mediated magnetic proximity accelerates oxygen evolution.

Investigation of nanofluids under microbial movement is a potential topic from applications point of view. This study focuses on the analysis of hybrid nanomaterial based microorganism model between finite boundaries. These boundaries consist of two walls having expansion or contraction property. Formulation of the problem comprises governing laws representing the flow of microorganism in the presence of physical effects and hybrid nanofluid effective characteristics. Similarity functions are adopted for conversion of the primary model into final form and then studied through Variational Iteration scheme. Successful implementation of the scheme provided considerable convergence and better results for the model with fluctuating physical parameters. It is found that increasing permeation and magnetic field significantly controlled the velocity in the channel. Presence of heat generation influentially enhances the temperature for both expansion and contraction cases; while the Soret effects help to augment the density motile of microorganism. The shear drag varies from 0.9057 to 1.1458 ([Formula: see text]), 0.9076 to 0.2470 ([Formula: see text]) in contraction case at the lower surface. This magnitude changes from 0.6762 to 0.6774 ([Formula: see text]), 0.6793 to 0.1558 ([Formula: see text]) at upper expanding surface. Contracting of the walls promoting this factor from 1.9017 to 1.8970 and 1.3982 to 1.3964, for [Formula: see text] and [Formula: see text], respectively. Further, the expanding walls heat transfer rate improves from 0.0509 to 0.0568, 1.4957 to 1.4981 and it depreciates from 0.0480 to 0.0461, and 1.4922 to 1.4839 in contracting walls.

White matter hyperinxtensity (WMH) and normal-appearing white matter (NAWM) are critical markers for tracking disease progression in cerebral small vessel disease (CSVD), indicative of a spectrum of white matter injury. The core pathological alteration underlying such injury is the disruption of myelin integrity and loss of axons. We hypothesized that the myelin content in WMH and NAWM may exert distinct effects on brain networks and cognition in CSVD. A total of 129 diagnosed CSVD patients were retrospectively enrolled. Myelin content was assessed with sub-voxel precision using iterAtive magnetic suscePtibility sources sepARaTion Quantitative Susceptibility Mapping (APART-QSM). Structural network redundancy was derived from diffusion tensor imaging (DTI). WMH and NAWM masks were generated. Associations between WMH/NAWM myelin content, structural network redundancy, and cognitive performance were examined using partial correlation and mediation analyses. Myelin content was significantly higher in NAWM than in WMH. Decreased structural network redundancy was significantly linked to myelin loss in NAWM but not in WMH. Moreover, redundancy indirectly linked NAWM myelin to cognition, whereas no such indirect pathway was observed for WMH myelin. No direct or total effect of myelin content on cognition was observed. These findings highlight the critical role of NAWM-related myelin integrity in preserving cognition through its association with structural network redundancy in CSVD.

Significant gold deposits occur within the ophiolitic rocks of the Central Eastern Desert of Egypt; yet, the structural controls governing ore distribution remain insufficiently constrained. This study applies an integrated remote sensing-aeromagnetic–structural workflow to the Um Salim area along the ENE-trending Barramiya–Um Salatit ophiolitic belt to delineate surface and subsurface architectures and assess their influence on gold localization. High-resolution lithological mapping was achieved through machine-learning classification of hyperspectral EnMap data using the Random Forest (RF) and Support Vector Machine (SVM) algorithms. SVM applied to enhanced Minimum Noise Fraction (MNF) components yielded superior performance, achieving an overall accuracy of 95.8%, a kappa coefficient of 94.6%, and an F1-score of 96.6%. Reduced-to-pole magnetic data reveal a prominent positive anomaly (~ 1400 nT) directly over the Um Salim gold mine, attributed to magnetite-bearing metavolcanics and ophiolitic serpentinite rocks. Upward continuation to 0.5–1 km confirms that this anomaly reflects a deeply rooted magnetic source. To refine structural interpretation, advanced edge-detection filters (TAHG and ILTHG) were applied, enhancing ENE–WSW, NE–SW, NW–SE, and N–S trends consistent with multi-phase deformation (D1–D3), and SAR-derived lineaments. Center for Exploration Targeting (CET)-based lineament density and orientation entropy maps delineate zones of intense structural complexity that closely correspond with mineralized shear zones and dyke-like porphyry intrusions. Depth-to-source analyses using Euler Deconvolution (EUD) and Tilt-Depth (TD) methods reveal that most magnetic bodies occur within 0–1000 m, whereas deeper (~ 1500 m) sources likely represent intrusive conduits that focused hydrothermal fluids. The novelty of this study lies in its integrated, multi-technique application of aeromagnetic analysis combined with hyperspectral machine learning to characterize a small, gold prospect and to map alteration-linked structural features at high resolution in the Barramiya–Um Salatit belt. The integrated results highlight new structurally complex zones in the eastern and southeastern Um Salim region as high-priority exploration targets, particularly along the NE–SW shear system that controls gold mineralization. This workflow provides a high-resolution, transferable strategy for targeting gold in structurally complex Precambrian terranes worldwide.

Endovascular interventions demand catheters that can actively steer through tortuous vessels and dynamically increase stiffness at the target to ensure precise therapy. Most existing steerable catheters achieve steering and variable stiffness (VS) by multiple sources, leading to reduced efficiency advantage, increased bulkiness, and safety risks. This work introduces a magnetic jamming method that allows steering and VS using one magnetic source. First, a carrier-free, matrix-free magnetic jamming scheme is introduced that directly encapsulates soft-magnetic powder in coaxial thin-walled tubes, enabling single-source field-driven steering and reversible VS via interparticle jamming. Next, an analytical micro-to-macro stiffness model is established that explicitly links field parameters and particle properties to catheter-level outputs (i.e., stiffness and steering angle) by incorporating particle interaction, thus providing closed-form, physics-based estimations. Finally, we validate the method at both tip and catheter levels, confirming the stiffness model and substantial field-tunable stiffness modulation (up to 300-fold), with benchmarking against vacuum jamming as a reference to validate its effectiveness and demonstrating a multifunctional prototype that enables both steering and VS using a single magnetic source. Our magnetic jamming approach enables on-demand steering and rapid, large-range stiffness modulation in millimeter-scale catheters, promising faster navigation with lower contact forces, more stable device deployment, and a clearer path to autonomous, workflow-friendly endovascular interventions.

Gold exploration in structurally complex Precambrian terranes remains challenging due to the heterogeneous distribution of hydrothermal alteration zones and the difficulty of distinguishing mineralization-related structures from regional tectonic features. Recent advances in integrated geophysical interpretation have demonstrated the importance of combining multiple datasets to improve structural targeting and hydrothermal mapping within the Arabian–Nubian Shield. The Um Balad area is a promising target for gold and copper exploration, with widespread hydrothermal alteration associated with quartz veins and sulfide mineralization. This study integrates airborne magnetic data, ground gravity surveys, geochemical analyses, and mineralogical investigations to characterize the structural framework and hydrothermal alteration related to mineralization in the area. Gravity and magnetic datasets were processed to delineate lithological boundaries, structural discontinuities, and intrusive bodies associated with hydrothermal activity. Structural interpretation reveals dominant NW–SE, NNW–SSE, E–W, NE–SW, and NNE–SSW fault systems controlling fluid migration and alteration zones. Processing techniques, including radially averaged power spectrum analysis, single-body modeling, and Euler deconvolution were applied to estimate the depth extent of magnetic and gravity sources, indicating both shallow and deep-seated causative bodies. Geochemical and mineralogical analyses were conducted on representative samples from the metagabbro–diorite complex and older granitoids using Spectral Analysis (ASD) and SEM–EDX (Scanning Electron Microscopy combined with Energy Dispersive X-ray Spectroscopy). The identified alteration assemblages include hematite, goethite, muscovite, chlorite, illite, kaolinite, and ferrihydrite. SEM–EDX results indicate significant enrichment in Au, Cu, and Ag, with maximum concentrations of 5.69 wt.% Au, 1.49 wt.% Cu, and 0.22 wt.% Ag. The integration of geophysical, mineralogical, and geochemical datasets demonstrates that structurally controlled hydrothermal alteration zones represent the principal targets for gold mineralization in the Um Balad area.

The study of the magnetic anomaly variation A and its relationship with iron ores

Focal cortical dysplasia (FCD) causes drug-resistant epilepsy requiring presurgical evaluation. Invasive electroencephalographic (EEG) studies demonstrate that sleep modulates epileptic activity, including interictal epileptiform discharges (IEDs), fast oscillations (FOs) in the beta (14-40 Hz) and gamma (40-80 Hz) frequency bands, and seizures. This study aimed to quantify sleep-associated changes in IEDs, FOs, and seizures in FCD patients using noninvasive magnetoencephalography (MEG). Nineteen patients with FCD were prospectively recruited and underwent simultaneous MEG/EEG recordings lasting 89 ± 19 min during daytime sleep. Sleep stages were classified from the EEG. Beamformer source signals were computed from the MEG signal to enhance sensitivity for visual detection of IEDs, FOs in the beta and gamma frequency bands, and seizures. Magnetic source imaging (MSI) was performed using the Maximum Entropy on the Mean (MEM) method, which is particularly sensitive to the spatial extent of sources, enabling accurate localization of epileptic activity. N1 sleep was reached in 17 of 19 patients and N2 sleep in 14 of 19 patients. Compared to wakefulness, sleep recordings showed significantly higher rates of FOs and seizures (both p < .05), whereas IED rates showed nonsignificant trends. Ten patients demonstrated FOs or seizures, and 12 showed IEDs. MSI of IEDs demonstrated consistent accuracy across vigilance states, with median Euclidean distances of 12.74 mm (interquartile range [IQR] = 22.74) in wake and 8.34 mm (IQR = 27.58) in sleep, and no systematic amplitude or spatial extent changes. Wavelet-MEM enabled frequency-specific source imaging, with FOs and seizures localizing concordantly to FCD lesions in five of seven and seven of eight patients, respectively. Daytime sleep MEG recordings are clinically feasible and significantly enhance the detection of seizures (37% of patients) and FOs compared to wakefulness. Sleep protocols enable noninvasive capture of ictal patterns-the gold standard for epileptogenic zone localization-alongside increased FO rates. These findings support incorporating sleep into standard MEG protocols for presurgical epilepsy evaluation.

Electrical stimulation is widely recognized as an effective strategy for promoting functional recovery after peripheral nerve injury. However, conventional stimulators rely on wired connections or implanted batteries, severely limiting implantability, biosafety, and clinical translation. Recent wireless, battery-free piezoelectric systems, primarily based on ultrasound or pressure-driven transduction, remain constrained by auxiliary equipment, working distance, and external control. Here, we report a fully wireless, circuit-free neural stimulator built on a millimetric magneto-mechano-electric (MME) cantilever transducer (3 × 10 × 5mm) with a barium titanate (BTO) piezoelectric ceramic core. Under low-frequency alternating magnetic fields, the MME cantilever mechanically oscillates, inducing stress on the BTO element and thereby converting magnetic energy into therapeutic electrical pulses. The use of BTO minimizes potential biosafety risks. Moreover, the device operates stably at 16cm from the magnetic source, outperforming most existing wireless stimulators. In vitro, MME-mediated stimulation doubles PC12 neurite outgrowth and neuronal differentiation. In a rat sciatic nerve injury model, the implanted stimulator exhibits excellent biosafety and significantly enhances nerve regeneration and motor recovery, achieving a ∼1.5-fold improvement in the sciatic functional index.

We present a first-principles investigation of the spin-ice state in Dy2Ti2O7using a magnetic source-free exchange and correlation (xc) functional, implemented in theCastepelectronic-structure code. By comparing results from the conventional local spin-density approximation, we show that a spin-ice state in Dy2Ti2O7can be reliably obtained by removing the magnetic sources from the xc contributions to the potential, and we contrast this against the computed ground states of other frustrated pyrochlore magnets.

Purpose The purpose of this study is to investigate the influence of different magnetic source locations on the flow behavior, heat and mass transfer and oxytactic bacterial distribution in a square cavity filled with Cu-water nanofluid, and to develop a neural network (NN) modeling of key transport characteristics. Design/methodology/approach Four distinct magnetic source configurations, left-located, bottom-located, right-located and top-located are examined for different physical parameters by using polyharmonic spline radial basis function (RBF) method. A comprehensive data set of 42,862 simulation cases is generated from numerical solutions and used for NN modeling of average Nusselt number, Sherwood number, and bacterial density. Model performance is evaluated using mean squared error (MSE) and feature importance analysis. Findings The results reveal that the bottom-positioned source produces the weakest damping, reducing flow velocity by just 18.30%, whereas the top-positioned source generates the most significant suppression, decreasing velocity by 95.77%. As Hartmann number increases, heat transfer degradation varies across configurations, with left-located source showing the largest reduction at 38.32%, while bottom-located source experiences the smallest decline at 10.16%. NN models demonstrate excellent predictive capability, achieving MSE values on the order of 10−5 even when trained with only 50% of the data set. The feature importance analysis reveals that Rayleigh number is the most critical parameter for predicting heat and mass transfer, while bacterial density predictions are governed by the Peclet number. Originality/value This study presents a novel combined numerical and machine learning framework for bioconvective nanofluid systems with varying magnetic source locations.

The magneto-mechanical coupling governing the response of magnetorheological elastomers (MREs) requires computational tools for their design and optimization. The existing frameworks are customarily based on ideal boundary value problems that optimize MREs under ideal, non-realistic homogeneous magnetic sources. We present an approach that addresses these limitations by solving strongly coupled magneto-mechanical partial differential equations within the optimization loop, explicitly accounting for external permanent magnets and their interaction with the deformable elastomer. The approach combines a coupled magneto-elastic boundary value problem with an auxiliary mesh-motion problem, which allows the free-space to deform consistently with the MRE geometry. The direction of the remanent magnetization in the MRE is represented by continuous design fields, updated through a gradient-based optimizer with adjoint sensitivities and filtering. A series of benchmark problems demonstrate the framework: robustness with respect to the initial guess; symmetry of the solution under reversed polarity; influence of magnet placement; transition between external-field and self-interaction dominated actuation; and adaptation to opposite objectives in a pull-push actuator. The results highlight how the explicit modeling of the free-space and the magnetic source leads to robust and physically consistent designs, providing a foundation for advanced MRE-based actuators.

The Chad Basin is an intracontinental basin originated from the actions of a number of peripheral uplifts making a periodic study of this basin imperative. On this background, an aeromagnetic data of the Chad Basin was used to identify some magnetic anomalies and determine the depth of the magnetic sources. The residual map obtained from the application of first order polynomial fitting to the total magnetic intensity data, revealed two magnetic anomalies. The low frequency anomalies emanated from the deep seated bodies with thicker sediments and perceived to be the magnetic basement while the high frequency anomalies resulted from shallower geologic bodies regarded as the sediments cover. The lineaments map showed that the long regional trends that lie in the directions ENE–WSW, WNW–ESE and E–W control the subsurface structure beneath the studied area. The magnetic field amplitudes vary from a maximum of 223 nT to a minimum of 96 nT depicting varying magnetic highs and lows as possible indication of undulating basement surface and magnetic traps. The depth to the basement range from about 0.5 km in the south to 3.0 km and deepens towards the north. The energy power spectrum estimated an average depth to the top of regional sources is about 7 km while the shallow sources have an average depth of about 1.5 km to their magnetic sources.

We present a novel and powerful constraint on the physics of supermassive black hole (BH) accretion disks. We show that in the outer disk (radii R ≳ 0.01 pc or ≳ 1000 R G ), models supported by thermal or radiation pressure predict disk masses which are much larger than the BH mass and increase with radius - i.e. rapidly-rising, extremely non-Keplerian rotation curves. More generally, we show that any observational upper limit to the deviation from Keplerian potentials at these radii directly constrains the physical form of the pressure in disks. We then show that existing maser and broad line region (BLR) kinematic observations immediately rule out the classic thermal-pressure-dominated Shakura Sunyaev-like α -disk model, and indeed rule out any thermal or radiation (or cosmic-ray) pressure-dominated disk, as the required temperatures and luminosities of the gas at large radii would exceed those observed by orders of magnitude. We show that models where the pressure comes entirely from turbulence (without thermal, radiation, or magnetic sources) could in principle be viable but would require turbulent Toomre Q ≳ 100 , far larger than predicted by self gravitating/gravito-turbulent models. However, recently proposed models of magnetic pressure-dominated disks agree with all of the observational constraints. These magnetically-dominated models also appear to agree better with constraints on maser magnetic fields, compared to the other possibilities. Observations appear to strongly favor the hypothesis that the outer regions of BH accretion disks are in the ‘hyper-magnetized’ state.

Electro-Pulse-Boring (EPB) generates electric breakdown channels in dielectric media to achieve efficient rock fragmentation for deep energy resource development. Strong magnetic fields have been shown to enhance the longitudinal penetration of plasma channels; however, the effects of magnetic-source position and field intensity on breakdown trajectory remain unclear. In this study, a numerical model called Rock Electrical Breakdown under Strong Magnetic fields model is established based on the solid-insulation breakdown theory, Kirchhoff's voltage law, and Maxwell's equations. The model is used not only to investigate how plasma channels initiate, propagate, and penetrate under different magnetic-field orientations, spatial positions of the magnetic source, and intensity of the external magnetic field but also to clarify how magnetic forces govern channel growth. The results indicate that the magnetic forces significantly promote the longitudinal development of the plasma channels. By adjusting the orientation of the magnetic field, the trajectory of the channel can be effectively controlled, thereby enhancing the performance of EPB. The axial distance between the magnetic source and the rock is identified as a key parameter that determines the distribution of the magnetic field within the rock, with the maximum extent of rock damage occurring at 6–8 mm. Moreover, increasing the intensity of the external magnetic field further accelerates the longitudinal extension of plasma channels and enhances the overall efficiency of EPB. This study may provide theoretical support for EPB technology assisted by strong magnetic fields.

Weak magnetic video recording with warm atomic ensembles constitutes a non-cryogenic and non-contact methodology for the magnetic source identification and failure reproduction. However, the spatial resolution, imaging speed, and shooting mode from traditional optical-pumping systems have constrained the real recording for ever-changing magnetic phenomena. This work reports a 684-pixel Bell-Bloom atomic magnetic-videorecorder with the global shutter and two-dimensional differential readout, for the real recording of changing gradient fields, which implements the free Larmor precession of Cs atoms to infer local magnetic information, employs a high-speed dual-quadrant Complementary Metal Oxide Semiconductor (CMOS) sensor with the global shutter and the extra microlens focusing to simultaneously detect differential optical rotations on all pixels. Also, a digital micro-mirror device (DMD) is employed to weigh the pixel crosstalk and the spatial resolution, and to facilitate the one-to-one pairing of the profiles for each differential probe beam pair projected onto the two CMOS quadrants. Furthermore, the average sensitivity is demonstrated to be 194 pT/ @0.5-178 Hz, with a high spatial resolution of 137 μm2 and a frame rate of 205 fps in a field of view up to 5 × 2.6 mm2. Finally, the magnetic distributions from a moving source have been experimentally measured and found to be in good agreement with the simulation results.

This article addresses the magnetic source localization problem by developing a receding horizon reinforcement learning approach. First, a Gaussian process regression approach is employed to model the magnetic environment and predict the magnetic strength distribution. Second, the predicted strength is used as the reward function for reinforcement learning. An important characteristic is that the reward function is time-varying as new magnetic data arrive. Third, owing to these time-varying rewards, a receding horizon control strategy is introduced into reinforcement learning to form the receding horizon reinforcement learning approach. The proposed approach not only retains the ability of the receding horizon control approach to deal with time-varying rewards, but also exploits the learning capability of reinforcement learning to adapt to the environment in real time. Finally, simulations and experiments illustrate the effectiveness of this proposed approach that guides a quadrotor to search and locate the magnetic sources.

Accurate magnetic dipole moment estimation for magnetic sources in medical and robotic applications

Migraine with aura (MwA) and migraine without aura (MwoA) are believed to have distinct pathophysiological mechanisms. However, differences in their neuromagnetic activity are currently unclear. To address this knowledge gap, this study employed magnetoencephalography (MEG) to examine alterations in magnetic source strength and functional connectivity (FC) between MwA and MwoA patients. Resting-state MEG data were recorded for 18 MwA and 18 MwoA patients during the interictal period and compared with 18 matched healthy controls (HCs). The spectral power and FC of the visual network were estimated using minimum norm estimation (MNE) combined with the Welch technique and corrected amplitude envelope correlation. Spectral power analysis revealed distinct frequency-dependent alterations in MwA in the left lateral occipital cortex (LOC), bilateral lingual cortices, and right transverse temporal cortex within the theta band compared with the MwoA and HCs groups. FC analysis revealed a distinct pattern of weakened FC in MwA in the low-frequency band between the visual cortex and several key regions, including the right entorhinal cortex, right rostral anterior cingulate cortex (ACC), right superior parietal cortex (SPC), left precentral cortex, and right precuneus cortex compared with the MwoA and HCs groups. The MwoA group exhibited significantly stronger FC within the ACC-visual cortex circuit in the gamma1 band compared with the MwA and HCs groups. Several abnormal FC metrics were significantly correlated with headache attack frequency in both migraine groups. This study revealed the distinct neuromagnetic signatures of MwA and MwoA, linking specific connectivity patterns to clinical features. These findings could potentially support the development of subtype-specific, targeted neuromodulation therapies for migraine.