Search Results (12,055)

Wave-edge milling tools can suppress chatter by introducing periodic harmonic variations along the cutting edge, which change the tooth-passing time delays between adjacent teeth. However, their stability is affected by coupled waveform parameters, such as amplitude, wavelength, and phase, making it difficult to screen suitable parameter combinations efficiently. This numerical/modeling-based study uses a previously validated multi-delay dynamic model to investigate the probabilistic relationship between pitch angle variance (PAV) and stability region area (SRA). A large number of feasible waveform-parameter combinations are generated under geometric constraints, and a PAV-based stratified sampling strategy is used to retain 54 representative parameter sets from six PAV layers for stability lobe diagram construction and SRA calculation. The results show that PAV has weak pointwise predictive capability for individual SRA values, with Pearson = 0.4234, Spearman = 0.4720, and R² = 0.179. However, the stratified statistical results reveal a clear layer-wise probabilistic tendency: the mean SRA increases from 17.962 to 20.996 in units of rpm·m, and the probability of obtaining an above-median SRA increases from 11.1% to 88.9%. The high-value tail case with PAV > 0.06 further indicates that a higher PAV does not necessarily guarantee a larger SRA for an individual parameter set. Therefore, PAV should not be used as a deterministic predictor or stand-alone tool-selection criterion, but can serve as a low-cost auxiliary probabilistic pre-screening descriptor before high-fidelity SLD/SRA evaluation. Full article

Hydrophobically modified chitosan has attracted considerable interest as an amphiphilic biomaterial for drug delivery, antimicrobial systems, and tissue engineering. Despite extensive research and promising biological performance, only a limited number of these materials have advanced toward clinically relevant technologies. This Perspective argues that the major barriers to translation are no longer related to biological efficacy but to insufficient reproducibility, inconsistent structural characterization, and limited attention to process engineering and scalable manufacturing. Rather than providing another comprehensive review, we discuss hydrophobically modified chitosan from a translational perspective, following its development from chemical modification and self-assembly to formulation engineering and representative biomedical applications. We highlight how molecular design, processing conditions, and material characterization collectively determine the reliability and practical applicability of these systems. Finally, we outline key priorities for future research, including standardized characterization protocols, harmonized experimental methodologies, and the implementation of engineering-oriented development strategies. We propose that future progress will depend less on introducing new chemical modifications and more on integrating polymer chemistry with process engineering to improve reproducibility and facilitate clinical translation. Full article

The conventional carrier phase-shifted pulse-width modulation strategy may cause asymmetric output phase voltages in a modular multilevel converter (MMC)-based static var generator, leading to high-frequency variations in the system common-mode voltage(SCMV). The resultant common-mode currents exacerbate insulation degradation and reduce equipment lifespan. To address this issue, this paper proposes a common-mode voltage (CMV) suppression method based on dynamic correction of the number of inserted submodules. By imposing the zero-SCMV condition as an insertion-number constraint, the proposed method dynamically corrects the numbers of inserted submodules in the three-phase arms, thereby suppressing the high-frequency SCMV fluctuations caused by the modulation process. Furthermore, integrating circulating current suppression techniques reduces the double-line-frequency alternating-current components components in inter-phase circulating currents, thereby enhancing the overall operational performance of MMC. Experimental validation on an RT-LAB-based rapid prototyping platform confirms the proposed method effectively mitigates high-frequency CMV variations. The results also show that this SCMV reduction is accompanied by increased output voltage total harmonic distortion (THD), which suggests that the proposed method is a compromise suppression strategy rather than a fully optimized modulation approach. Full article

Background: The directional relationship between epigenetic age acceleration (EAA) and musculoskeletal disease remains unresolved. This study integrated bidirectional Mendelian randomization (MR) with multi-layer genomic evidence to evaluate directionality, shared genetic architecture, and robustness to instrument definition. Methods: Four EAA clocks (IEAA, PhenoAA, HannumAA, and GrimAA) and ten musculoskeletal phenotypes were analyzed in a 10 × 4 bidirectional two-sample MR design. EAA instruments underwent GRCh37 functional annotation, genome-wide-significant external-association screening for the index variants and European linkage-disequilibrium proxies, pair-specific Steiger filtering, and conservative Set A/B/C sensitivity analyses. The juvenile-arthritis reverse models underwent instrument-flow reconstruction, strength assessment, liability-scale directionality testing, and minimum-detectable-effect analysis. Additional analyses comprised LD score regression (LDSC), PLACO+ cross-trait locus mapping, Bayesian colocalization, multivariable MR (MVMR) with exact-SNP matched univariable comparators, and integrated evidence synthesis. Results: Forward MR yielded two nominal HannumAA associations. The inverse HannumAA–spondyloarthritis estimate remained directionally consistent across the original, Steiger-filtered, and conservative external-association-filtered sets, whereas the HannumAA–pain-in-thoracic-spine estimate lost nominal significance in the conservative set; no forward result survived correction across 40 tests. GrimAA forward estimates were sensitive to use of the fallback instrument threshold. Reverse MR identified ten nominal associations. For juvenile arthritis, three harmonized instruments had F statistics of 51.25–102.35; liability-scale Steiger comparisons supported the tested direction under all 16 outcome-by-prevalence combinations, although the 788-case discovery GWAS and possible winner’s curse remained important limitations. LDSC identified FDR-significant positive genetic correlations of GrimAA with hip osteoarthritis (r_g = 0.267, p = 8.49 × 10⁻⁵, q = 0.0019) and knee osteoarthritis (r_g = 0.269, p = 9.52 × 10⁻⁵, q = 0.0019). PLACO+ identified 738 genome-wide-significant cross-trait variants and 65 independent loci; six of 37 evaluable loci showed strong colocalization. Of 96 MVMR models, 43 had primary-exposure conditional F ≥ 10, and 32 also had candidate-trait conditional F ≥ 10. After exact-SNP matching, the 43 primary-strength models were operationally classified as 35 partially attenuated and eight independent-signal models, with no fully attenuated model; no adjusted association survived multiplicity correction. Conclusions: The results support a prioritized genomic map with substantial instrument- and model-specific uncertainty. Disease-to-clock signals were richer than clock-to-disease signals, GrimAA shared polygenic architecture with osteoarthritis, and selected loci showed strong shared-variant evidence, while the MR and MVMR findings remained unsuitable for definitive causal or mediation claims. Full article

Atomic Force Microscopy (AFM) uses oscillating cantilever-shaped microprobes to measure nanometer-scaled sample topography. Spatial resolution of AM-AFM is determined by the dynamics of the cantilever-sample system including thermomechanical noise of the cantilever. Conventional AFM systems drive the cantilever harmonically in resonance, where resolution can only be improved by changing system and process parameters. We take a different approach keeping cantilever, sample, and control method (AM-AFM) unchanged. Instead, we operate the AFM cantilever in nonlinear parametric resonance. The corresponding excitation scheme is produced via electronic feedback. Because of the artificial source of the nonlinear parametric excitation, we implement arbitrary system behavior and prove the theoretical findings experimentally. We analyze the influence of excitation parameters on dynamic system behavior including an explanation of the nonlinear limitation mechanism of the cantilever amplitude in parametric instability and amplitude reduction mechanism during approach of the cantilever to the sample. We find a mechanism which could reduce tip damage. The dependence of the cantilever’s thermomechanical noise on parametric excitation is investigated. Our analysis yields the resolution of parametric resonance AFM and enables systematic selection of parametric excitation parameters to improve resolution of existing AFM systems. We provide evidence that responsivity is enhanced by 30%, thermomechanical noise by a factor of 4.5, and resolution by a factor of $5.7$ for identical systems when parametric resonance AFM is used. Full article

Non-intrusive measurement of the local electric-field direction in SF₆ gas-insulated equipment is important for insulation-condition assessment and electric-field distortion analysis. In this study, a three-projection electric-field direction measurement method based on electric field-induced second-harmonic generation is proposed. The feasibility of the method is validated using a known reference electric field, and the effects of electric-field strength, laser pulse energy, SF₆ pressure, and spatial electric-field non-uniformity on the direction-retrieval results are systematically investigated. The results show that increasing the electric-field strength or laser pulse energy enhances the second-harmonic modulation signal and thus reduces the direction-retrieval deviation. SF₆ pressure has a non-monotonic influence on the effective accumulation of the second-harmonic signal and the direction-retrieval accuracy through the competition between increased molecular number density and enhanced phase mismatch. Spatial electric-field non-uniformity weakens the ability of the three-projection retrieved direction to represent the local electric-field direction at the focus. Under the present experimental conditions, the maximum absolute angular deviations in the strongly non-uniform edge regions of the cylindrical and hemispherical electrodes are 6.68 ± 1.62° and 9.20 ± 1.84°, respectively. Full article

High-frequency monitoring of suspended sediment concentration (SSC) is important for sustainable river management, but conventional cross-sectional measurements and single-sensor satellite observations cannot simultaneously provide fine spatial detail and sufficient temporal continuity. This study evaluated whether Harmonized Landsat and Sentinel-2 (HLS) observations can improve SSC monitoring in the middle and lower Liaohe River, China. Daily mean cross-sectional SSC records from five hydrological stations were matched with same-day HLS L30 and S30 surface reflectance observations during the ice-free months from 2016 to 2022. Three Ridge regression schemes, including L30-only, S30-only and L30 + S30 fusion models, were assessed using date-grouped cross-validation, temporal extrapolation, station extrapolation and quality-based reliability labeling. The fusion model achieved an out-of-fold RMSE of 0.329, MAE of 0.245 and R² of 0.454 on the log10(SSC) scale, with negligible bias and no clear accuracy degradation relative to the best single-sensor schemes within sensor-specific subsets. The L30–S30 union increased valid observation days by 64.6% compared with the single sensor with a greater number of valid observation days at each station and raised station-month availability to 87.9%. Reliability labels based on clear-water pixel number and proportion helped identify lower-error observations, while spatial transferability varied more substantially among stations than temporal extrapolation. These results show that HLS fusion improves the temporal availability of quality-screened SSC observations in medium-width rivers, although uncertainty remains greater at the extremes of the SSC range and when the model is transferred to new cross-sections. Full article

The Philippine Sea Basin is one of the world’s largest marginal sea basins, and the spatiotemporal variation characteristics of its sound speed field hold significant importance for deep-sea navigation and positioning as well as underwater acoustic detection. This study investigates the sound speed field in the central Philippine Basin (130.0–134.0° E, 17.5–20.5° N) using the Global Ocean Physics Analysis and Forecast product from the European Union’s Copernicus Marine Environment Monitoring Service (CMEMS), cross-validated with the U.S. HYCOM (Hybrid Coordinate Ocean Model), and independent verified against 69 Argo profiles. We systematically investigate the spatiotemporal variation characteristics of the sound speed field in this region. Temperature and salinity consistency between the two products is established (deviations of <0.5 °C and <0.05 ppt below 400 m), with CMEMS selected as the primary data source for its higher accuracy and greater temporal stability. Three sound speed formulae—Del Grosso, Chen–Millero, and TEOS-10—are intercompared, with TEOS-10 yielding the highest accuracy in cross-validation; it is therefore recommended for its rigorous thermodynamic consistency. Vertical sound speed profiles are evaluated using bi-exponential, Munk canonical, and fourth-order polynomial models. Among them, the bi-exponential model achieves the optimal balance between physical interpretability and fitting accuracy (RMSE = 2.77 m/s, inter-monthly correlation coefficient = 0.857). Its two exponential decay scales characterize the upper-ocean thermocline and the deep stratification, respectively, avoiding the physically unrealistic deep-water fluctuations exhibited by the polynomial model (RMSE = 2.68 m/s) and the poorer generalization of the Munk model (RMSE = 2.97 m/s). Horizontal gradient analysis reveals a cross-directional correlation of approximately 0.5 between sound speed gradients and ocean currents, reflecting the combined modulation of sound speed gradients by Kuroshio advection and thermodynamic stratification. The general gradient control scale is estimated at approximately 100 km × 100 km, confirmed by cross-method consistency between K-means and Gaussian mixture model clustering. Temporal analysis demonstrates that sound speed peak-to-peak variation attenuates rapidly with depth (from ~8.9 m/s at 50 m to <0.1 m/s at 4000 m), and EOF (empirical orthogonal function) analysis reveals that the first four modes explain over 99% of the total variance, with harmonic fitting identifying annual and semi-annual cycles as the dominant periodic components. Sound channel axis depth varies seasonally between 900 and 1125 m (deeper in winter, shallower in spring), with axis sound speed stable at 1480–1484 m/s (slightly higher in winter, slightly lower in spring) and axis thickness ranging from 225 to 450 m (wider in winter, narrower in spring). These results provide prior critical constraints for underwater acoustic positioning, AUV navigation, and long-range sound channel communication and navigation in the central Philippine Sea region. Full article

Global plastic production and inadequate waste management have led to widespread environmental contamination with microplastics (MPs), now detected in food, water, and air. Their small size, diverse polymer composition, and capacity to carry chemical additives and co-pollutants facilitate intestinal uptake and raise concerns about their potential impact on gut microbiota. This review synthesizes current evidence on how MPs influence gut microbial composition and function, gut barrier integrity, and associated inflammatory and metabolic pathways. We conducted a narrative review of in vivo animal studies, in vitro simulated gut systems, and human observational studies that assessed MP exposure, gut microbiota profiles, and downstream toxicological outcomes. MPs originate from primary and secondary sources and can act as vectors for metals and organic pollutants. Following ingestion, they may cross the intestinal barrier via endocytic and persorption routes, acquire a protein corona, and be recognized by immune cells, activating TLR/NF-κB, and MAPK pathways alongside oxidative stress. In these models, MP exposure induces dysbiosis, characterized by loss of beneficial SCFA-producing bacteria (e.g., Bifidobacterium, Lactobacillus, Bacteroides) and expansion of pathobionts (e.g., Escherichia/Shigella, Staphylococcus, Enterobacteriaceae), accompanied by altered bile acid metabolism. These microbiota and metabolic alterations are linked to increased gut permeability, intestinal inflammation, metabolic dysfunction, and, in some studies, reproductive and neurobehavioral effects. Current evidence supports MPs as emerging modulators of gut microbial and intestinal homeostasis. However, heterogeneity across experimental models, reliance on high exposure doses, and lack of standardized MP characterization limit robust risk assessment. These limitations underscore the need for harmonized methodologies, longitudinal large-scale human studies, and the development of targeted mitigation strategies. Full article

This paper estimates end-use demand elasticities for European Union residential energy consumption and applies them to projections of household energy demand up to 2030 and 2050. Using a 2013–2023 panel for the EU27, we estimate country fixed-effects demand equations with Driscoll-Kraay standard errors for total household energy and five Eurostat end-use categories: space heating, space cooling, water heating, cooking, and lighting and appliances. The explanatory variables are heating and cooling degree days, real household electricity and gas prices, and real GDP per capita. The estimated elasticities are applied to six scenarios that combine two climate trajectories with three energy-price pathways, calibrated to international policy scenarios. These pathways are price approximations of the corresponding IEA scenarios; technology, electrification, and fuel-mix transformations are not modeled. We also examine stylized Renovation Wave sensitivities that impose reductions of 20%, 40%, and 60% in projected space-heating energy demand. The results show that EU27 residential energy demand is projected to fall by 2% to 12% by 2050 across the six scenarios, mainly because of reductions in heating demand, which dominate increases in cooling demand in absolute energy terms. Under the central scenario, total demand falls by 4.0%. Renovation sensitivities imply substantially larger reductions, ranging from 17% to 40%. The findings highlight the importance of building-envelope improvements, cooling-related adaptation, and end-use heterogeneity in long-run residential energy-demand policy. The paper contributes a harmonized end-use projection framework that links climate exposure, household energy prices, income, and building-envelope efficiency within a single empirical model of EU residential energy demand. Full article

Although electric vehicles have been widely adopted in recent years, insufficient charging infrastructure in remote areas may still compromise the continuity of emergency operations involving field medical electric vehicles (EVs). Motivated by the need for temporary DC energy support from a donor vehicle to a field medical EV, this paper investigates an isolated DC–DC energy-sharing converter based on a series-resonant dual-active-bridge (SRDAB) topology and its associated control method. First, the SRDAB converter is employed to satisfy the requirements of low-voltage input, galvanic isolation, voltage step-up, and DC power transfer. Based on the fundamental harmonic approximation (FHA), a steady-state power relationship and a control-oriented dynamic model are derived to characterize the coupling between the phase-shift angle, transferred power, and output voltage. Subsequently, a fractional-order model predictive control strategy tuned offline using the grey wolf optimizer (GWO-FOMPC) is developed to address donor-side input-voltage variations, recipient-side equivalent-load disturbances, and the nonlinear power-transfer characteristics of the SRDAB converter. In this strategy, a fractional-order proportional–integral outer loop generates the reference transferred power, while a fractional-order predictive inner loop analytically determines the phase-shift command online. Finally, simulations and converter-level experiments validate the dynamic regulation performance of the proposed control strategy under emulated energy-sharing conditions for field medical EVs. Full article

During the operation of full-ceramic bearings, defects such as cracks and spalls inevitably develop on the bearing balls. These defects reduce bearing service life and compromise the stable operation of mechanical systems. To address this issue, a 12-degree-of-freedom (DOF) dynamic model of a full-ceramic bearing-rotor system (BRS) is established, considering ball crack and spalling defects. The model incorporates variations in equivalent stiffness and contact forces induced by these two defect types. Subsequently, the proposed model is solved by the Newmark–β method. Bifurcation diagrams, time-domain waveforms, and frequency spectra are employed to investigate the system’s dynamic responses. In the frequency-domain analysis, particular attention is paid to characteristic frequency components, including the rotational frequency f_s, the ball spin frequency f_BSF, their harmonics, and combination frequencies. Finally, an experimental test platform is constructed to validate the accuracy of the developed model. The results indicate that crack and spalling defects exert distinctly different effects on the dynamic behavior of the system. Defect width has a significant quantitative influence on the vibration response. Under various defect conditions, the prediction errors of the developed model remain within an acceptable range, with the maximum relative error of 9.05%. The developed model offers a theoretical foundation for analyzing bearing dynamics and supporting fault diagnosis applications. Full article

The rapid electrification of marine transportation has increased the number of hybrid marine microgrids with the addition of renewables and energy storage. The continuously varying propulsion loads, fluctuating sea states, and renewable intermittency introduce significant challenges in bidirectional power transfer and power quality enhancement in marine vessels. This work presents a power-oriented operational strategy for a hybrid Roll-on/Roll-off (Ro-Ro) ferry-based marine microgrid (FMG) integrating diesel generators (DGs), Solar Photovoltaic (PV) arrays, and battery energy storage systems as the primary power sources. The proposed FMG adopts a hybrid AC/DC bus configuration linked through a bidirectional voltage source interlinking converter (ILC). The ILC facilitates multiple functionalities, including effective load compensation, mitigation of Total Harmonic Distortion (THD), continuous power support through bidirectional energy exchange, maintenance of balanced sinusoidal currents, and unity power factor (UPF) operation, thereby providing an integrated solution for improved power quality and reliable microgrid performance. A supervisory control (SC) is devised to operate the FMG seamlessly under islanded modes depending on the availability of power sources. To achieve the above-mentioned objectives, a power-optimized Dual Power-based Instantaneous Power Theory (DP_IPT) is employed and it involves a Sequential Delay Signal Cancelation (SDSC)-based Phase-Locked Loop (PLL) for the effective extraction of sequence components, so as to address the unbalance and nonlinearities in an effective manner with reduced oscillations. The proposed control strategy reduces diesel generator utilization through the effective integration of Solar PV and battery support during anchoring operation. The integration of renewable energy sources substantially enhances clean energy utilization, resulting in the reduction of overall carbon emissions, accounting for a near-40% decrease in emissions compared with the conventional diesel generator (DG)-based operating mode. The proposed FMG and control framework are validated through the Hardware-in-the-Loop (HiL) approach employing an OPAL-RT (OP4512) real-time controller. The HiL investigations demonstrate the efficacious working of the proposed control in achieving less carbonized and enhanced power quality operation for next-generation electrified hybrid maritime microgrids. Full article

This study presents the development and validation of the nationwide ground motion monitoring system of InSAR.Hungary, which is designed to produce deformation monitoring products harmonized with the European Ground Motion Service. The proposed workflow integrates PSI results with GNSS-derived deformation models within a consistent framework. As a methodological contribution, it introduces an optimization-based spatial reference point selection method, which combines kernel density estimation with global optimization, and its extended formulation permitting subsequent utilization of a virtual reference. In addition, a simplified calibration strategy is also implemented, reducing the calibration of InSAR with GNSS data to a superimposing step, under the assumption that large-scale deformation components are introduced only by GNSS to the calibrated results. The system is validated through cross-comparisons, first against the European Ground Motion Service. The results reveal low-amplitude, spatially heterogeneous large-scale residual patterns between the products, which are potentially attributable to differences in the handling of long-wavelength phase and deformation components between the models. After accounting for these effects, the residual differences exhibit no significant bias and remain consistent with random spatial variability, indicating statistical agreement between the models. This finding is also supported by the outcome of the cross-comparison of InSAR.Hungary and observed GNSS-based deformation measurements. These findings confirm the reliability of the proposed workflow and establish InSAR.Hungary as a consistent framework for wide-area ground motion monitoring with practical applicability in geodetic and operational contexts. Full article

The mechanical behavior of calcareous sand differs significantly from that of conventional quartz sands, leading to challenges in offshore geotechnical engineering applications. This distinctive response is closely associated with the complex three-dimensional morphology of calcareous sand particles. However, existing characterization methods are often limited to specific morphological scales and cannot fully describe the multiscale complexity of particle shape. To address this issue, this study performs a comparative morphological analysis of calcareous sand (CS) and Fujian quartz sand (FS) across three particle-size ranges by integrating X-ray micro-computed tomography with spherical harmonic (SH) analysis. Individual particles are reconstructed using SH representation, and a multiscale morphology characterization framework is developed by decomposing particle morphology into three distinct scale levels: large-scale form represented by sphericity, medium-scale angular features represented by roundness, and small-scale surface texture represented by roughness. The results demonstrate that CS and FS exhibit distinct morphological characteristics across different scales, while particle-size effects remain less pronounced within the investigated range. Furthermore, the SH amplitude spectra reveal statistically self-similar characteristics of particle surfaces, allowing the fractal dimension to be correlated with multiscale morphological descriptors. The proposed framework provides a quantitative description of complex particle morphology across multiple scales and may facilitate further investigations of particle-scale mechanical behavior in granular materials. Full article