Deterministic lateral displacement (DLD) is an effective method of microparticle separation that has always been constructed of monolithic arrays of obstacles. By cylindrically revolving the 2D geometry through a complete circle, deterministic radial displacement (DRD) devices can be fabricated in segments and assembled without constraints on axial rotation. In contrast to prior work, this enables a reusable and reconfigurable system that represents a genuine step forward for DLD usability. It is not known how the critical particle size changes for strongly curved DLD geometries. We use COMSOL simulations of 2D and cylindrically swept geometries to show that the critical size changes slightly depending on curvature. We use low-cost resin 3D printing to build and test a scale version of a DRD device with a nominal critical size of 134 μm. The experimental device enriches particles between 134 and 200 μm by an average of fourfold. The DRD device is disassembled, cleaned, and reused 3 times, with one in 10 segments replaced each time. Advances in 3D printing technology will reduce the critical size and increase the durability of future DRD systems. This will make the modular, reusable, and high throughput DRD system highly attractive for a wide range of sample prep and purification applications.

An optimal lower hybrid current drive antenna has been designed for the Alborz tokamak using Multiphysics simulations performed in COMSOL. The study systematically investigates the influence of key parameters—including the antenna phasing configuration and radial displacement, along with the scrape-off layer plasma density, which is modeled under electron cyclotron resonance preionization—on the accessibility, and coupling efficiency of lower hybrid waves (LHWs) in the Alborz tokamak. The unique operational characteristics of the Alborz tokamak define a minimum value of N ∥ crit = 1.59, while the antenna achieves a representative value of N ∥ = 3.56 via the optimal phasing configuration of 120 deg, satisfying the LHW accessibility condition. Furthermore, this phasing configuration directs the power spectrum of launched LHWs asymmetrically in one toroidal direction, aligned with the electron ohmic drift, resulting in significantly enhanced power coupling. This is achieved through the attainment of the minimum reflectivity below 10% and maximum directivity of 72% when the plasma density exceeds the cutoff density of 7.44 × 10 16 m − 3 at the source frequency of 2.45 GHz , which is critical for current drive. Additionally, a radial antenna displacement of 2 cm , corresponding to the plasma density of 1.2 × 10 17 m − 3 , is identified as optimal, as it achieves the least reflectivity and enhances electric field intensity in the toroidal direction.

The process of corrosion cracking in reinforced concrete is important for understanding the durability evolution behavior of reinforced concrete. However, most of the proposed models in the literature are based on differential equations, which are computationally expensive when solved using traditional numerical methods, and they do not provide uncertainty quantification of the predicted results. In this study, a physics-guided probabilistic deep learning framework integrating Bayesian inference and physics-informed neural network (PINN) is proposed for modeling corrosion-induced cracking in reinforced concrete. Unlike existing PINN-based approaches that yield only deterministic predictions, the proposed framework embeds the governing physical equations directly into the Bayesian neural network training process, simultaneously enforcing physical consistency and quantifying prediction uncertainty. The Mean Absolute Percentage Error ( MAPE ) for the corrosion expansion force and radial displacement of the steel-bar concrete contact surface were 0.58% and 4.6%, respectively, demonstrating high prediction accuracy. The quantified uncertainty bounds provide engineers with reliable confidence intervals for the predicted corrosion expansion force and radial displacement, supporting structural inspection decision-making and risk-based maintenance planning. Finally, the effects of various parameters on modeling performance and stability were systematically investigated, offering practical guidance for model configuration in similar physics-informed probabilistic learning tasks.

The scalable integration of solid-state quantum emitters into photonic nanostructures remains a central challenge for quantum photonic technologies. Here, we demonstrate a robust and streamlined integration strategy that tackles the long-standing issue of deterministic fabrication on randomly positioned self-assembled quantum dots (QDs), leveraging a buried-stressor-based site-controlled InGaAs QD platform. We show that this deterministic growth approach enables precise spatial alignment with circular Bragg grating (CBG) resonators for enhanced emission, eliminating the need for complex and time-consuming deterministic lithography techniques. We fabricated a 6 × 6 SCQD-CBG array with 100% device yield, with 35 devices falling within the radial-offset range where the simulated photon-extraction efficiency (PEE) exceeds 20%, underscoring the spatial precision and scalability of our fabrication concept. A systematically selected subset of five devices with varying radial displacements reveals clear offset-dependent trends in PEE, degree of linear polarization, spectral linewidth, and photon indistinguishability, thereby establishing quantitative bounds on spatial alignment tolerances. In the best-aligned QD-CBG device, we achieve a PEE of (47.1 ± 3.8)% (corresponding to an end-to-end system efficiency of 3.4%), a linewidth of (1.41 ± 0.22) GHz, a radiative decay lifetime of (0.80 ± 0.02) ns, a single-photon purity of (99.58 ± 0.18)%, and a Hong-Ou-Mandel two-photon interference visibility of (81 ± 5)% under quasi-resonant excitation at saturation power. We confirm our conceptual understanding of the effect of emitter-position dependent charge-noise fluctuations in terms of a quantum-optical model for the (quantum-)emission properties. The established nanofabrication platform provides a reproducible, lithography-compatible route to scalable, high-performance single-photon sources (SPS), offering a powerful alternative to conventional lithography-based deterministic integration techniques.

ABSTRACT This study develops a bidirectional dynamic seepage–stress–damage coupling model using FLAC3D to elucidate the hydro-mechanical coupling mechanisms of permeable linings in water diversion tunnels under high internal water pressure. Utilizing continuum damage mechanics and equivalent tensile and plastic strains, it governs damage evolution, integrating a dynamic feedback mechanism where permeability and mechanical parameters degrade alongside damage.Results show that post-construction, the lining remains undamaged under compression. During the pressurisation stage, exceeding a critical internal water pressure initiates micro-cracks. Increased pressure propagates these into macroscopic fractures, raising local reinforcement stress and permeability, ultimately causing lining–rock interfacial debonding. Post-failure, rapid seepage transfers the water load to the surrounding rock mass, which becomes the primary load-bearing component and undergoes further damage.The model effectively captures the ‘seepage-damage’ positive feedback mechanism and water pressure transfer characteristics. Because damage and radial displacement peak at the tunnel invert, targeted grouting and reinforcement there during construction are recommended for overall structural safety.

Micro-particle image velocimetry (micro-PIV) is a powerful imaging method for resolving flow fields in microscopic systems, but its application to rapidly deforming gels requires key modifications. Here, we adapt micro-PIV to quantify contraction dynamics of active actomyosin gels without invasive tracer beads by tracking local myosin-generated actin inhomogeneities. We show that accurate displacement measurements depend critically on optimizing the time interval over which displacements are computed and the number of frames used in ensemble correlation, relative to the poroelastic timescale and stage of contraction. To assess reliability, we quantify four complementary metrics: displacement vector fields, displacement-magnitude maps, radial profiles of radial and tangential displacement components, and ensemble-averaged orientation with rotational measures. Incorporating the elastic response of the gel, we extract radial strain profiles under an axisymmetric approximation and demonstrate robustness for irregular geometries and off-center contractions. Across conditions, we observe common radial signatures consisting of inward radial contraction with peak displacement at intermediate radii and effective radial stretching near the boundary. These deformation fields provide a basis for inferring spatial and orientational distributions of motor-generated active stresses using appropriate constitutive models. Our approach advances quantitative analysis of active poroelastic materials and has broad applications in biomaterials design, cytoskeletal dynamics, and morphogenesis.

We critically reanalyze the relativistic precession model of quasi-periodic oscillations, exploring its natural extension beyond the standard harmonic approximation. To do so, we show that the perturbed geodesic equations must include anharmonic contributions arising from the higher-order expansion of the effective potential that cannot be neglected a priori, as commonly done in all the approaches pursued so far. More specifically, independently of the underlying spacetime geometry, we find that in the radial sector the non-negligible anharmonic correction is quadratic in the radial displacement, i.e. ∝ δr 2, and significantly affects the radial epicyclic frequency close to the innermost stable circular orbit. Conversely, polar oscillations δθ remain approximately decoupled from radial ones, preserving their independent dynamical behavior. To show the need of anharmonic corrections, we thus carry out Monte Carlo-Markov chain analyses on eight neutron star sources of quasi-periodic oscillations. Afterwards, we first work out the outcomes of the harmonic approximation in Schwarzschild, Schwarzschild-de Sitter, and Kerr spacetimes. Subsequently, we apply the anharmonic corrections to them and use it to fit the aforementioned neutron star sources. Our findings indicate that the standard paradigm requires a systematic generalization to include the leading anharmonic corrections that appear physically necessary, although still insufficient to fully account for the observed phenomenology of quasi-periodic oscillations. Accordingly, we speculate on possible refinements of the relativistic precession model, showing the need to revise it at a fundamental level.

Flexural-guided-wave mode F(1,1) based inspections for small-bore tubes with bends.

Abstract This study investigates the magnetic restoring forces in axial flux permanent magnet synchronous machines (AFPMSMs) under rotor tilting and radial displacement conditions for three magnet configurations: single magnet, 4-segment Halbach array, and 8-segment Halbach array. Finite element analysis (FEA) was employed to characterize the restoring behaviour and assess system stability. The results reveal that while single magnet structures offer greater restoring force at high tilting angles, Halbach arrays provide stronger and more stable restoring forces within limited angles, especially as the number of segments increases. However, this improvement comes at the cost of higher complexity and fabrication effort. For radial displacements, the restoring force also increases significantly with the number of Halbach segments. In a dual-motor configuration, the use of direct current enables active control in the Z-axis, enhancing levitation stability and dynamic response. These findings provide valuable insights into optimal magnet topology and control strategies for AFPMSMs intended for use in magnetically levitated left ventricular assist devices (LVADs), where compactness, precision, and reliability are critical.

The OSCA family proteins are pivotal mechanosensitive ion channels in plants, playing a crucial role in sensing osmotic stress and initiating drought adaptation pathways. Despite significant progress in structural biology, the dynamic conformational pathway of gating, the cooperative mechanism of key residues, and the mechanism of selective permeation for different cations remain largely elusive. In this study, we employed molecular dynamics (MD) simulations to systematically investigate the Arabidopsis OSCA3.1 channel in its contracted, expanded, and mutant open states. Conventional MD simulations reveal that the transition from the contracted to the open state is accompanied by a significant conformational rearrangement involving the tilting of the M6 helix. This movement drives the radial displacement and reorientation of key hydrophobic residues (e.g., F504, F505), thereby dismantling the hydrophobic gate composed of continuous hydrophobic residues and creating physical space for ion permeation. Steered molecular dynamics (SMD) simulations show that both K+ and Ca2+ must overcome substantial resistance when traversing the hydrophobic constriction. However, due to its higher charge density and dehydration energy, Ca2+ requires a significantly larger driving force than K+. Umbrella sampling calculations yielded potential of mean force (PMF) profiles, quantitatively revealing the free energy barrier differences for the permeation of the two ions for the first time. The results indicate that although their permeation pathways are similar, Ca2+ faces a significantly higher free energy barrier than K+ (Ca2+: ∼53 kcal/mol vs K+: ∼30 kcal/mol) due to stronger hydration and the higher energy cost of dehydration associated with its higher charge density. Electrostatic potential analysis further shows that the hydrophobic gating region within the pore is electrically neutral, facilitating the passage of various cations, while the lower part is electronegative, a distribution that may favor initial ion entry and subsequent guidance. This study demonstrates that the opening of the OSCA3.1 channel is a highly cooperative conformational reorganization process dominated by helical motion. Although its internal environment allows for the passage of multiple cations, from an energetic perspective, the conduction of monovalent K+ is more favorable in this expanded state. These findings demonstrate that OSCA proteins exhibit a "kinetic selectivity" rather than being "completely nonselective," where mechanical force or osmotic pressure modulates the degree of channel opening, thereby dynamically affecting the selective transport efficiency of potassium and calcium ions. This provides a novel atomistic mechanism and energetic theoretical basis for understanding how plants differentially regulate the transmembrane flux of the osmotic balance ion (K+) and the signaling ion (Ca2+) through the same channel when sensing osmotic stress.

Topological photonic crystals provide a powerful platform for manipulating light. However, their flexibility in realizing diverse far-field beam profiles and polarization states is limited by the number of spatial symmetries lattices can provide. Here, we demonstrate plasmonic Dirac-vortex lasers with controlled polarization and intensity distributions by engineering photonic mass vortices in a three-dimensional parameter space. We design plasmonic Dirac-vortex cavities consisting of honeycomb lattices of aluminum nanoparticles, where photonic mass vortices are achieved by arranging distorted unit cells in an angular winding configuration. By manipulating the radial and azimuthal displacements of the nanoparticles as well as their size, taken as the third dimension of the system, we predict far-field radiation with spatially programmable polarization states and asymmetric intensity distributions. Experimentally, this is achieved by integrating organic dye molecules within the plasmonic Dirac-vortex cavities. Our work establishes a paradigm for multi-dimensional mass-enabled cavity engineering, which offers flexibility in sculpting exotic photonic states with broad implications for photonic circuits, quantum devices, and bosonic systems.

A novel shallow oil chamber hybrid journal bearing with adjustable oil chamber depth was designed based on piezoelectric ceramics, inspired by conventional shallow oil chamber bearing structures. The computational fluid dynamics method is used to analyze the bearing characteristics of shallow oil chamber bearings, including the volume flow, the seal oil pressure, load capacity and stiffness. An experimental platform equipped with signal acquisition device and piezoelectric ceramic control device was developed. The eddy current sensors collected the displacement signal at the shaft end. The required voltage was calculated by the displacement signal. The piezoelectric ceramics elongated or shortened, causing a displacement of the same magnitude in the depth of the oil chamber, thereby controlling the radial displacement of the shaft. The adjustment effect of this bearing was verified by experiment for no-load and 500 N load at 200–1000 rpm, with a baseline initial oil chamber depth of 20 and an oil supply pressure of 2 MPa. The results showed that compared with the case without adjustment, the accuracy in Y direction has increased from 8.9 μm to 1.9 μm (max. 78.4%) after adjustment. Under the above load conditions, the displacement can be controlled below 2 μm, indicating a significant improvement in shaft vibration resistance.

ABSTRACT To investigate the influence of cracks on the response characteristics of explosive columns under drop-weight impact, a finite element simulation model of a drop-weight impacting an RDX-based aluminized explosive column was established. Columns without cracks, with a close fit, with 1 mm cracks, and with 1.5 mm cracks were prepared, and drop-weight impact loading experiments were conducted. The computational results indicate that the crack edge is the point of maximum stress during drop-weight loading, and the radial displacement of nodes around the crack is significant. Compared to intact and close-fit columns, columns with cracks exhibit a significant increase in the internal maximum stress, stress rate, strain, strain rate, and radial flow velocity, with the magnitude of increase being greater for wider cracks. Drop-weight loading experiments show that the ignition thresholds for aluminized explosive columns under impact are essentially equivalent under no-crack and close-fit conditions. When a crack is present, the ignition threshold under impact significantly decreases. A flow phenomenon of internal material from high-density to low-density regions was observed at the half-radius position along the column axis. The experimental results show good consistency with the simulation results.

ABSTRACT An approach to dynamically determine the separation between transmit and receive coils in electromagnetic systems based upon measurement of the primary field induced voltages was presented. This approach proposes an adaptation of primary-field-based localization schemes suitable for a two-horizontal-coil setup common to many ground-based or towed transient electromagnetic platforms. It was shown that the dominant influence on primary field induced voltages was radial displacements and that neglecting other tangential displacements and/or rotation effects introduced only minor offset biases in an approach that assumed a radial offset was solely responsible for the on-time voltages. Secondary fields produced by a conductive earth were shown to perturb on-time measurements during intervals of rapid current change in the transmit loop, and recommendations for reducing these influences were discussed. Field results indicated a 10 s of centimeters localization of the receiver can be achieved for offsets up to 20 m.

Numerical investigation of electromagnetic pulse welding for aluminium-steel tubular joints

Interstitial fluid flow within the osteonal lacunar-canalicular system (LCS) is crucial for osteocyte mechanotransduction and bone remodeling. This study aims to develop a three-dimensional finite element model of an osteon with gradient-varying boundary conditions to systematically investigate how mechanical loading, outer wall constraints, and pulsatile blood pressure modulate intra-osteonal fluid flow. This study constructs a three-dimensional finite element model to systematically analyze the dynamic responses of fluid flow behavior under gradient boundary conditions. Gradient parametric analyses were performed by varying: (1) axial strain amplitudes (250-5000 με) to simulate different activity levels; (2) radial displacement constraints at the outer wall (0- 0.042 μm) to represent confinement by surrounding tissues; and (3) pulsatile blood pressure amplitudes (A = 0-2.5) at the inner wall to mimic physiological to hypertensive conditions. The resulting pore pressure, fluid velocity, and fluid shear stress (FSS) distributions were analyzed. All parameters exhibited axisymmetric distributions. Peak pore pressure, fluid velocity, and FSS increased nearly linearly with strain magnitude, ranging from 1.7×104 to 1.4×105 Pa, 1.69×10-8 to 3.50×10-8 m/s, and 0.34 to 6.5 Pa, respectively. Relaxation of outer wall constraints from fully constrained (0 μm) to fully elastic (0.042 μm) significantly reduced all three parameters. Elevated pulsatile blood pressure markedly increased intra-osteonal pore pressure (from 2.7×104 to 6.5×104 Pa) but had minimal effect on velocity and FSS. A subsequent multiscale validation using an explicit LCS model showed that the macro-scale poroelastic model accurately captures global trends, while local FSS within canaliculi is amplified by a factor of 1.5-2.5. The gradient boundary condition approach effectively quantifies the differential and synergistic effects of mechanical load, structural constraint, and vascular pressure on the osteonal fluid environment. These findings provide a quantitative framework for understanding mechanotransduction in bone and may inform clinical strategies for managing bone adaptation and disease.

An accurate mathematical model serves as a fundamental analytical tool for examining the behavior response of mechanical systems. In order to investigate the kinetic behavior of a bearing-rotor-bearing coupled multibody system with localized failures, the mathematical models of flexible rotor and flexible disk based on Timoshenko beam theory and Kirchhoff plate theory are developed in this study, as well as the bearing model considering the time-varying misalignment factor. Then these components are integrated into a novel modeling framework for bearing-rotor-disk systems, which is employed for a detailed analysis of modal responses, operational mechanisms, and the effects of bearing faults and unbalance on system dynamics. The result demonstrates a pronounced coupling relation between rotor structure and rolling bearings, the rotor bending places the bearing in a persistently misaligned operational state, leading to the unavoidable generation of bearing contact angles. The maximum contact angle exceeds 10° when the rotor systems are operated under heavy-load and high-speed and conditions, and the bearing clearance becomes negative, resulting in severe degradation of system stability and nonlinear characteristics. Severe shock is produced due to the bearing raceway defect, and high-frequency fluctuations in bearing contact angle are generated as a result of oscillations in radial displacement of rollers, while the minimum clearance of the bearing is lost by 32.21%, and the contact stiffness is increased by 0.249%. The vortex motions of rotor system will be induced by unbalance faults, node orbit are characterized by circular geometry, and a positive linear correlation is observed between ball-ring contact frequency and rotor working frequency.

Distinguishing physiological meniscus mobility from pathological extrusion remains a clinical challenge, particularly regarding the prevention of osteoarthritis. While cadaveric studies suggest that meniscectomy increases contact stress, the in vivo dynamics of the healthy meniscus under load-specifically the role of the meniscotibial (coronary) ligament-remain poorly defined. This study aimed to establish a physiological reference standard for load transmission and contact area kinematics in the healthy knee. In a biomechanical MRI study, nine healthy male subjects underwent high-resolution 3T MRI with prospective motion correction. Knee joints were scanned in an unloaded state and under a physiological axial load of 400N. We performed 3D segmentation to quantify changes in cartilage-to-cartilage and cartilage-to-meniscus contact areas, differentiating between femoral and tibial interfaces. Axial loading significantly increased the direct cartilage-to-cartilage contact area, with a predominant increase in the medial compartment (+ 15.0%) compared to the lateral compartment (+ 6.7%), reflecting the physiological adduction moment. Conversely, the overall meniscus-to-cartilage contact area decreased. A detailed compartmental analysis revealed a distinct kinematic pattern: while the femoral-meniscal contact area significantly decreased due to relative motion, the tibial-meniscal contact area remained stable. This study defines the in vivo healthy baseline of knee contact mechanics. The results demonstrate that under physiological load, the healthy meniscus undergoes controlled radial displacement to facilitate direct cartilage contact. Crucially, the stability of the tibial contact area supports the hypothesis that the meniscotibial (coronary) ligament acts as a primary anchor, preventing excessive extrusion at the tibial interface. These data serve as a vital benchmark for evaluating meniscus repair techniques and differentiating physiological mobility from pathological failure.

Permanent magnet synchronous motor is widely used in a high-performance control system, but its cogging torque and torque ripple will affect the precision of the control system. Stable motor operation necessitates the reduction of slot torque and torque ripple. The stress of part of the rotor will also change after reducing the reduce the slot torque and torque ripple. This paper reduces the slot torque and torque ripple considering the change of rotor surface stress, which has reference value for the design of magnetic pole moving rotor. Firstly, experiments verify the accuracy of the finite element model. Secondly, the slot torque and torque ripple under different polar arc coefficients are analyzed in ANSYS Workbench, and the appropriate polar arc coefficients are obtained. In addition, to further reduce the torque ripple, three pole changing methods are proposed, and the slot torque and instantaneous torque of each pole changing method under different shift angles are analyzed. The simulation results show that the torque pulsation can be significantly reduced by the two adjacent pole-changing methods, and the average torque changes little. To analyze the stability of the rotor after pole changing, the stress analysis of the magnetic pole moving model is carried out. The simulation results show that the filling block can effectively reduce the stress concentration of the sleeve, so it is necessary to assemble the filling block in the magnetic pole moving rotor. According to the results of torque and stress analysis, it is showed that the rotor model is optimized by the method of the adjacent-pole shifting Angle of 5 degrees, and the slot torque is reduced by 74.92%. Finally, to ensure the safe operation of the rotor, the rotor dynamics analysis is carried out to study the radial displacement of the sleeve under the rated speed. According to the simulation results, the magnetic pole movement has little effect on the critical speed, and it increases the radial displacement response of the rotor. This paper reduces the slot torque and torque ripple considering the change of rotor surface stress, which has reference value for the design of magnetic pole moving rotor.

The axisymmetric nanocontact problem with surface effect and friction is modeled by an elastic theory based on surface energy density (C–Y theory). In the model, a non-classical boundary condition incorporating the surface effect is derived. With the methods of Love’s strain function and Hankel integral transformation, explicit integral-form solutions of the displacement and stress fields in the elastic half-space are obtained under the axisymmetric normal and tangential loadings. A dimensionless parameter, [Formula: see text], proportional to surface energy density of half-space [Formula: see text] and inversely proportional to the product of shear modulus [Formula: see text] and contact radius [Formula: see text], is introduced to characterize the surface effect. The results show that the surface effect reduces the radial and normal displacements, which makes the half-space stiffer. Besides, the surface effect also reduces the normal and shear stresses within the contact area. Due to the friction, the radial displacement and shear stress become larger, whereas the normal displacement and normal stresses become smaller. Such a fundamental model and corresponding results should be helpful to the deep understanding of the surface effect on nanocontact behavior.