Accurate plantar pressure distribution is important for biomechanics, gait analysis, rehabilitation, and diabetic foot assessment. However, wearable plantar pressure systems are often limited by sparse sensor layouts due to hardware complexity, power consumption, and user comfort constraints. This study proposes a multimodal deep learning framework for static plantar pressure prediction using plantar geometry information and sparse landmark constraints. A convolutional block attention module U-Net architecture was developed to integrate plantar geometry and sparse landmark modalities through dual-encoder feature fusion with attention refinement. Different network architectures, fusion strategies, and landmark densities were systematically evaluated using a controlled-variable experimental design. Results demonstrated that feature-level fusion consistently outperformed data-level fusion and unimodal configurations across all landmark densities. The proposed model achieved the best performance with a normalized root mean square error of 0.087 using 16 landmarks, and the same model maintained a normalized root mean square error of 0.138 using only two landmarks, indicating promising reconstruction performance even under highly sparse sensing conditions. Marginal contribution and synergy analyses further showed that feature-level fusion more effectively captured complementary interactions between plantar geometry and sparse anatomical guidance, particularly under sparse landmark conditions. These findings suggest that multimodal feature-level fusion provides an effective strategy for sparse-to-dense plantar pressure reconstruction and may support the development of low-cost intelligent insole systems for biomechanical monitoring and clinical applications.

Synchronous gas cooling-assisted laser directed energy deposition is a novel method for the in-situ active regulation of the microstructure of Ti6Al4V alloy. This study systematically investigates the influence of different gas cooling flow rates on the grain evolution and phase structure characteristics of Ti6Al4V alloy fabricated by laser directed energy deposition, and reveals the thermal behavior mechanism through numerical simulation. The results show that, with increasing gas cooling flow rate, the α′ phase gradually transforms from an acicular morphology to a lath-like morphology, accompanied by a significant reduction in aspect ratio and a substantial improvement in size uniformity. Regarding β grain evolution, increasing the gas cooling flow rate suppresses the transition from columnar grains to equiaxed grains, promotes columnar grain growth, significantly reduces texture intensity, and increases dislocation density. However, the β grain size exhibits a trend of first decreasing and then increasing. Temperature-field analysis indicates that the cold jet induces a pronounced heat-sink effect through forced convective heat transfer, forming a distinctive temperature field characterized by lower temperatures in the cold-jet action zone and higher temperatures on both sides. Increasing the gas cooling flow rate not only reduces the peak temperature of the molten pool, but also increases the temperature gradient and cooling rate at the solidification interface, effectively narrowing the heat-affected zone and phase-transformation zone, while improving the temperature-field uniformity behind the center of the cold jet.

Wearable systems based on inertial measurement units (IMUs) have attracted considerable interest in recent years in the field of gait analysis. However, most gait studies using such devices have been conducted in laboratory rather than clinical settings. This study evaluated a commercially available IMU-based insole system in two cohorts: a clinical group (59 ± 18, years) recruited from podiatry clinics and a non-clinical group (28 ± 7, years) recruited from a university with no reported complaints. Participants wore the IMU-based device and performed treadmill walking (clinical group) and overground walking (non-clinical group). Spatiotemporal parameters were compared between groups using statistical analyses included the Shapiro-Wilk test, Mann-Whitney test, and Welch's t-tests for non-bilateral data, and a two-factor linear mixed-effects model estimated by restricted maximum likelihood (REML) for bilateral spatiotemporal parameters to evaluate group, foot-side, and interaction effects. Ten of the twenty-two spatiotemporal parameters showed significant group differences, with statistical significance observed in at least one foot for parameters measured bilaterally. The observed differences may reflect a combination of clinical characteristics, age-related effects, and walking environment influences. Findings are discussed in relation to potential biomechanical mechanisms, factors influencing results and the clinical utility of IMU systems. Future research should investigate specific foot conditions under standardized walking conditions with age-matched cohorts.

Wearable sensors are used in gait analysis to obtain spatiotemporal parameters, with gait events serving as critical markers for foot and lower limb movement. Summarizing detection methods is essential, as accurately identifying gait events and phases are key to deriving precise spatiotemporal parameters through wearable technology. However, a clear understanding of how these sensors, particularly angular velocity and acceleration signals within inertial measurement units, individually or collectively, contribute to the detection of gait events and gait phases is lacking. This review aims to summarize the current state of knowledge on the application for both gyroscopes, with particular emphasis on the role of angular velocity signals, and inertial measurement units with both angular velocity and acceleration signals in identifying gait events, gait phases, and calculating gait spatiotemporal parameters. Gyroscopes remain the primary tool for gait events detection, while inertia measurement units enhance reliability and enable spatiotemporal parameter estimation. Rule-based methods are suitable for controlled environments, whereas machine learning offers flexibility to analyze complex gait conditions. In addition, there is a lack of consensus on optimal sensor configurations for clinical applications. Future research should focus on standardizing sensor configurations and developing robust, adaptable detection methodologies suitable for different gait conditions.

The recrystallization behavior, texture evolution, and grain growth kinetics of cold-drawn MP35N alloy with 77.1% strain were systematically investigated through recrystallization annealing at varying temperatures and durations, employing EBSD and TEM characterization methods. Key findings reveal that annealing parameters significantly influence texture development. As recrystallization temperature increases, the deformation texture gradually diminishes, with orientation evolution primarily following the alpha-fiber. After 950 degrees C/1h treatment, the microstructure achieves near-random orientation, with recrystallization nucleation predominantly occurring through sub-grain boundary migration. Notably, deformation twin coarsening was also observed during this process. When maintaining 950 degrees C, extended holding time drives the recrystallization texture through three distinct stages: initial development of {001}(110) texture, transition to near-random orientation, and subsequent re-emergence of {001}(110) texture. Correspondingly, recrystallized grain growth exhibits rapid initial progression followed by gradual deceleration, consistent with the BECK equation. Additionally, the study observed that multiple annealing twin variants with different orientations can initiate within individual grains.

The hot tearing susceptibility of Al–Zn binary alloys with solute contents of Al–0.5%Zn, Al–1%Zn, Al–2%Zn, and Al–4%Zn, with all compositions being in wt%, is investigated through physical experiments and numerical simulation. The temperature at the hot spot, the designed critical point for hot tearing, and the load at the end of the test bar are measured and compared with the simulation results. The test samples with 0.5 and 1.0% Zn show hot tears while those with 2.0 and 4.0% Zn have no sign of such tearing. The correlation between solid fraction, strain, stress, and hot tearing indicator is revealed using the simulation results of the Al–1%Zn and Al–4%Zn alloys. Just before solidification, the Al–1%Zn alloy is found to have not only a much higher strain rate at the hot spot of the test bar than that of the Al–4%Zn alloy, but also a higher strain gradient along the longitudinal direction. It is believed that both the high strain rate and high strain gradient are attributable to the formation of hot tears in the Al–1%Zn alloy.

Improving the degradation performance and enhancing the biocompatibility are the main challenges of Mg-based biodegradable implants. In this study, a nano-hydroxyapatite-enhanced (nHA) Mg matrix composite was fabricated via friction stir processing and characterised, including microstructure, mechanical, in vitro degradation properties, and cytocompatibility. Hydroxyapatite is renowned for its superior bone compatibility, promoting healing responses and tissue growth. Friction stirring created a gradient grain structure in the alloy, with the stir zone exhibiting the highest grain refinement. The stir zone also contained most of the incorporated nHA and exhibited a strong texture with grains preferentially oriented along the [0001] direction. Immersion and polarisation experiments showed an increase in the FSPed WE43-nHA's corrosion resistance due to the refined microstructure. The treatment also caused a shift in the corrosion mode of the alloy from localized to uniform corrosion despite some localized corrosion associated with the nHA. Cytocompatibility tests in human osteoblast (HOB) cell lines indicated good biocompatibility in the Mg-nHA alloy, with cells exhibiting relatively healthy morphology and increased live cell count. Friction stir processing is a viable manufacturing option for creating Mg-based metal matrix composites with improved corrosion resistance and good biocompatibility.

The mechanical properties of Zn–0.4Mg binary alloys were improved by adding different mass fractions of Ca during the casting process. The microstructure, mechanical, electrochemical, and degradation properties of Zn–0.4Mg–nCa alloys were thoroughly investigated. The results demonstrate that the ternary alloys’ microstructure comprised matrix Zn and precipitated phases (Mg2Zn11 and CaZn13). The grain size of the ternary alloys was gradually refined with increased Ca content, and the quantity and composition of eutectic phases were altered. The tensile strength of the Zn–0.4Mg–0.4Ca alloy reached 161.12 MPa. The immersion test demonstrated that when the Ca content increased, the corrosion rate of the Zn–0.4Mg–nCa alloys gradually increased. In addition, the alloys’ corrosion mechanisms in simulated body fluids were discussed.

Plantar pressure distribution offers insights into foot function, gait mechanics, and foot-related issues. This systematic review presents an analysis of the use of artificial neural network techniques in the context of plantar pressure analysis. 60 studies were included in the review. Sample size, pathology, pressure sensor number, data collection device, utilization of other sensor devices, ground-truth methods, pre-processing dataset, neural network type, and evaluation metrics were evaluated. Utilization of customized wearable footwear devices for the acquisition of data was common amongst both healthy participants and patients. Inertial measurement units emerged as an effective compensatory measure to address the limitations associated with the distribution of plantar pressure. Ground truth methods predominantly relied on the usage of both annotations and reference devices. Multilayer perceptron, convolutional neural networks, and recurrent neural networks were identified as the most frequently employed artificial neural network algorithms across the reviewed studies. Finally, the evaluation of performance largely drew upon statistical descriptions and other machine learning methods. This review provides a comprehensive understanding of the use of artificial neural network techniques in plantar pressure analysis, highlighting opportunities for future research.

A pulsed magnetic field (PMF) can cause significant grain refinement in solidified alloys. However, the evolution of forced flow and grain size by varying pulse length and the proposed mechanism of grain refinement driven by PMF are still controversial. The present paper systematically investigates the evolution of electromagnetic fields and fluid flow induced by PMF inside a Ga–20 wt pctIn–12 wt pctSn alloyed melt and the corresponding changes in grain size of Al–7 wt pctSi alloy with increasing pulse length in comparison with electric current intensity and frequency. It is found that the magnetic flux density adjacent to the mould wall almost remains constant, whereas the peak value of eddy current density and Lorenz force is reduced when the pulse length is increased from 1.6 to 12 ms. In addition, the flow intensity inside the melt firstly increases and then decreases when the pulse length is gradually enlarged. However, the magnetic flux density, eddy current density, Lorentz force and flow intensity inside the melt are all strengthened with an increase of the electric current intensity. The distribution and peak value of magnetic flux density, eddy current density and Lorentz force cannot be changed by the applied electric current frequency. Since the time over which the Lorentz force is applied is prolonged with increasing frequency, a positive correlation between the flow intensity and the frequency is achieved. The results of corresponding solidification experiments in Al–7 wt pctSi indicate that the grain size experiences the same evolution with flow intensity by varying the electric current intensity, frequency and pulse length. It is most likely that the dominant mechanism of grain refinement under applied PMF is the fragmentation of dendrites induced by forced flow rather than heterogeneous nucleation promoted by PMF.

Refinement of grains and intermetallic phases in the as-solidified alloy structure offers uniform structural properties, eliminates or minimizes common solidification defects, including segregation and hot cracking, and improves thermomechanical processing of wrought alloys. Melt processing by an external field is an efficient process for achieving refinement of the solidification structure of Al and Mg alloys without altering the alloy composition. A wide range of melt processing methods and solidification studies (conventional, directional, and in-situ approaches) have been reported in the literature that explore the mechanism of refinement. Identifying the dominant grain refinement mechanism has been a focus of most investigations because significant variations exist according to the casting conditions and the type of applied external treatments. The origin of fine grains occurs through either one or a combination of heterogenous nucleation, fragmentation of dendrites and grains formed and then separated from the surface of the melt and mould wall under vibration or agitation. The first part of this review describes the prominent external field techniques and the mechanisms proposed for the origin of fine grains. The second part critically compares the current understanding of these grain refinement mechanisms to determine differences and commonalities to identify the factors that promote the formation of equiaxed zones occupying a large volume fraction of the casting.

This work reveals the role of Mg additions on deformation behaviours of Zn-Mg alloys during room temperature compression at moderately high strain rate of -0.5 s-1. Experimental results from scanning electron microscopy, transmission electron microscopy and electron backscatter diffraction provide insight into the deformation behaviours and dynamic recrystallization mechanisms operative in Zn-0.08%Mg and Zn-0.8%Mg alloys. The primary dynamic recrystallization mechanisms in the Zn-0.08%Mg alloy were continuous dynamic recrystallization in conjunction with twin-induced dynamic recrystallization. After straining to a true strain of 161%, the Zn0.08%Mg alloy displayed a uniform and heavily refined microstructure with an excellent combination of strength and plasticity. For the Zn-0.8%Mg alloy, particle-induced dynamic recrystallization activated by eutectic structures played a critical role in addition to continuous and twin-induced dynamic recrystallization mechanisms. Fine and soft-oriented grains which formed in proximity to the eutectic accommodated large amounts of localized plastic strain. This resulted in inhomogeneous strain partitioning which restricted dynamic recrystallization kinetics in hard-oriented grain interior regions due to insufficient slip activity to support continuous dynamic recrystallization. Therefore, a partially recrystallized microstructure was maintained in the Zn-0.8%Mg alloy up to true strain of 161%.

A refined, equiaxed grain structure and the formation of finer primary intermetallic phases are some of the notable benefits of ultrasonic processing of liquid/solidifying melts. Ultrasonic treatment (UST) has been widely explored in Al and Mg-based alloys due to its operational versatility and scalability. During UST, the refinement of grain and primary intermetallic phases occurs via cavitation-induced fragmentation mechanisms. In addition, UST improves the efficiency (activation of particles) of the conventional grain refinement process when potent particles are added through master alloys. Though the UST’s ability to produce refined as-cast structures is well recognized, the understanding of the refinement mechanisms is still debated and unresolved. Significant efforts have been devoted to understanding these mechanisms through the use of sophisticated techniques such as in-situ/ real-time observation, lab-scale and commercial-scale casting processes. All these studies aim to demonstrate the significance of cavitation, fragmentation modes, and alloy chemistry in microstructure refinement. Although the physical effects of cavitation and acoustic streaming (fluid flow) are primary factors influencing the refinement, the dominant grain refinement mechanisms are affected by several solidification variables and casting conditions. Some of these include melt volume, solute, cooling rate, potent particles, grain growth (equiaxed, columnar or dendritic), and the cold zones of the casting where the onset of nucleation occurs. This review aims to provide a better insight into solidification variables emphasizing the importance of cold zones in generating fine structures for small- and large-volume (direct chill) castings. Another important highlight of this review is to present the relatively less explored mechanism of (acoustic) vibration-induced crystallization and discuss the role of cavitation in achieving a refined ingot structure.

This paper reported a surface modification method to improve corrosion resistance and biocompatibility of a Ti3Zr2Sn3Mo25Nb alloy (named as TLM). A 100-μm-thick layer with an average grain size of 70 nm was created on the alloy surface through sliding friction treatment (SFT), followed by a micro-arc oxidation treatment (MAO) to create a porous coating. Phase composition, morphology, structural characteristics, and elemental characteristics of the MAO coating were inspected by scanning electron microscope (SEM), energy-dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). Corrosion resistance of the MAO coating was tested by electrochemical method, and the biocompatibility of the MAO coating was evaluated by cell adhesion and proliferation, and protein adsorption tests. It has found that the surface morphology and chemical composition of the MAO coating produced on the SFT surface (NG-MAO) were not significantly different from those of the MAO coating formed on the original TLM substrate without SFT (CG-MAO). However, the corrosion current density of the NG-MAO coating in 0.9% NaCl solution (PS) and simulated body fluid (SBF) solution decreased 43.4 and 46.7%, respectively, as compared to the CG-MAO coating. The polarization resistance of the NG-MAO coating was also 122% higher than that of the CG-MAO coating in PS. And the protein adsorption capacity and cell proliferation have been significantly increased on the NG-MAO coating compared to its counterpart, the CG-MAO coating.

The gradient porous Ti3Zr2Sn3Mo25Nb (TLM) alloy rods were fabricated through sintering the alloyed powder to a solid core. The porous sample was then modified by a Micro Arc Oxidation (MAO) treatment in an electrolyte containing calcium and phosphate, a hydrothermal treatment enabled secondary microporous hydroxyapatite (HA) coating, and a further bone morphogenetic protein-2 (BMP-2) loading treatment through immersion and freeze-drying. The treatment led to an orderly secondary microporous coating containing HA nano-particles and evenly distributed BMP-2 in the porous coatings. As a result, osteoblasts could adhere and grow well on the coatings with a high cell adhesion rate and cell functional activity. The in-situ shear testing indicated that the interfacial strength had been enhanced significantly. Improvement of the bond formation and osseointegration with the titanium implant is attributed to increased surface area for the cell to attach, creating voids for the cell to grow in, and activating titanium surface by introducing bioactive ingredients such as HA and BMP-2.

Novel microstructural features were found in the Ti−Nb−Zr−Mo−Sn alloy manufactured by Laser Engineered Net Shaping (LENS). Examination of the microstructure showed that the fabricated sample exhibits a layered morphology with arced deposit boundaries. Novel distributions and morphologies of various phases including β, α, α'' and ω were detected in the LENS-manufactured part which substantially differ to conventionally processed alloy counterparts. The β grains and subgrains spread over multiple deposits and layers, aligned to the build direction, forming a complex network microstructure comprising large highly textured columnar grains aligned to β phase <001> orientations. The α precipitates have needle-like shapes and are widely distributed across a majority of the deposited layers, whereas the nanoscale ω particles were present in regions absent of α precipitation. Localised, massively transformed α'' phase with a very long and curved rod-like shape and substantial surface defects was identified. The formation of these novel microstructural features is investigated and discussed in the context of the characteristics of the LENS fabrication process. The microstructures are attributed to the complex thermal history in the unique deposit-by-deposit and layer-by-layer method employed during LENS additive manufacturing in conjunction with the complex precipitation behaviours exhibited by TiNb-based alloys. The characteristics and formation mechanisms of the LENS-manufactured Ti−Nb−Zr−Mo−Sn alloy microstructures revealed here provide a basis to optimize LENS and post-LENS heat treatment processes to optimize microstructures for improved performance.

A comparison study between an electric current applied in the pulsed mode (ECP), ultrasonic treatment (UST), and melt stirring treatment (MST) was performed to understand the origin of equiaxed grains during the solidification of pure Al. ECP and UST were applied at 760°C and 700°C before the onset of nucleation, and at one temperature range after the onset of nucleation at 661°C. UST produces excellent refinement in all three temperature ranges compared to ECP. Interestingly, application of the MST process at 661°C over the surface of the solidifying melt also resulted in significant refinement comparable to that of UST (grain size of ~260–460 μm).ECP, UST, and MST techniques differ in terms of the dominant mechanism influencing the grain refinement. Therefore, the present work analyses and discusses the grain refinement mechanisms based on nucleation, fragmentation, and a crystal separation mechanism for the origin of fine grains.

A process to dealloy a Ti-3Zr-2Sn-3Mo-25Nb (TLM) titanium alloy to create a porous surface structure has been reported in this paper aiming to enhance the bioactivity of the alloy. A simple nanoporous topography on the surface was produced through dealloying the as-solution treated TLM alloy. In contrast, dealloying the as-cold rolled alloy created a hierarchical micro/nanoporous topography. SEM and XPS were performed to characterize the topography and element chemistry of both porous structures. The roughness, hydrophilicity, protein adsorption, cell adhesion, proliferation, and osteogenic differentiation were tested. The elements of Zr, Mo, Sn, and Nb were depleted at the nanoporous TLM surface with a diameter of 15.6 ± 2.3 nm. Dissolving the microscale α phase from the alloy surface contributed to the formation of the microscale grooves on the surface. The simple nanoporous topographical surface exhibited hydrophilicity and higher protein adsorption ability, which facilitated the early adhesion of osteoblasts compared with the hierarchical micro/nanoporous surface. On the other hand, the hierarchical micro/nanoporous surface improved cell proliferation and differentiation and still retained the contact guidance function, which implied good bonding for osseointegration. This research revealed the effect of phase composition on the surface morphology of dealloying titanium alloy and the synergistic effect of micron and nanometer topography on the function of osteoblasts. This paper therefore provides insights into the surface topological design of titanium-based biomaterials with improved biocompatibility.

The formation of fine, non-dendritic equiaxed grains throughout a casting without the addition of refiners (i.e. independent of alloy chemistry), is made possible by using ultrasonic, magnetic or pulsed magnetic and electric current pulse techniques. The dominant mechanisms proposed for the grain refinement produced during the application of an external field are cavitation phenomena assisted nucleation or fragmentation of dendrites (ultrasonic field), wall crystals arising from the cold surface of the mould (electric current pulse, magnetic and pulsed magnetic fields). In all these cases fluid flow provides an additional contribution (e.g. reduced temperature gradients, growth rate and remelting of dendrites) to maintaining an equiaxed grain structure. The origin of equiaxed grains under an external field also depends on the casting conditions (volume and shape of casting) and the type of alloy other than the mechanisms specific to a particular technique. The current work aims to provide a detailed understanding of the various factors and mechanisms that influence the grain refinement achieved during the solidification of pure metals (magnesium and zinc) subjected to UltraSonic Treatment (UST). The role of the temperature range of UST application, time duration and an unpreheated sonotrode are examined with respect to the origin, evolution of equiaxed grain structure, morphology and the columnar to equiaxed transition. The origin of grains was analysed from three fundamental aspects that contribute to refinement (i) heterogeneous nucleation (ii) fragmentation of existing dendrites and (iii) grains produced from the colder surfaces (arising from mould walls or vibrating surfaces as wall crystals). A comparison of UST refinement with mechanical, low-frequency vibration, electric current pulse and magnetic field solidification of pure metals has also been provided to highlight the importance of the cold surfaces (sonotrode and mould wall) in influencing grain refinement. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.