This study evaluated the effects of different printing orientations on the mechanical properties and surface roughness of a 3D-printed definitive resin-based composite (RBC) material. Bar shaped samples were fabricated from a 3D-printed RBC (VarseoSmile TriniQ) using three different build orientations (0°, 45°, and 90°) and lithium disilicate ceramic (IPS e.max CAD). Flexural strength and elastic modulus were evaluated using a three point bending test. Surface microhardness was assessed with a Vickers hardness test, and surface roughness was measured using a contact profilometer. Following mechanical testing, the sample surfaces and fractured regions were further examined by scanning electron microscopy (SEM) for topographic and fractographic evaluation. Statistical analysis was performed at α = 0.05 using one way ANOVA, with post hoc comparisons conducted using the Tamhane test. Significant differences were observed among the tested materials for all evaluated parameters (p < 0.001). IPS group demonstrated superior mechanical properties and lower surface roughness compared to the 3D-printed RBCs. Within the 3D-printed groups, the 0° build orientation exhibited higher flexural strength, whereas the 90° orientation showed increased surface hardness. Elastic modulus and surface roughness were not significantly influenced by printing orientation (p > 0.05). SEM analyses supported the quantitative findings by revealing a homogeneous and compact microstructure in IPS group and orientation-dependent surface and fracture features in the 3D-printed RBC groups. IPS e.max CAD demonstrated superior mechanical performance. The 0° orientation improved flexural strength, while the 90° orientation enhanced surface hardness, suggesting that build orientation should be selected according to the intended clinical function.

Rheology of Tear Lipid Components and Their Influence on Surface Properties.

ABSTRACT Coal preparation serves as a fundamental technology for achieving clean and efficient utilization of coal, while screening constitutes a critical unit operation within this process. Conventional screening methods often exhibit limited effectiveness in the efficient screening of moist fine coal, poor particle permeation and low screening efficiency. In this study, a strong vibration elastic screening method was proposed, and the flexural motion characteristics of the screen surface with the excitation parameters was explored. The motion behavior of the material was analyzed during screening process, and the influence of the excitation frequency, excitation force and processing capacity on the 3 mm screening efficiency was discussed. The results show that the attached impact beam below the screen surface collided with the screen during the screening process, inducing flexural deformation in the elastic screen surface (ESS). This deformation facilitated the passage of lodged particles and effectively prevented blinding. By regulating key parameters such as the excitation force and frequency, the degree of flexural deformation of the screen surface could be adjusted, thereby achieving improved screening performance. Under the small vibration of the screen body, the screen surface can output a larger vibration intensity. When the excitation force was 7.66 kN, the excitation frequency was 16.67 Hz, and the feed rate was 15.42 t/(h-m2), the screening efficiency reached the maximum value of 90.56%. This study provides new insights for the efficient screening of fine materials.

Precise control over thin-film morphology and interfacial organization is essential for solution-processed organic electronics. We demonstrate the successful Langmuir-Blodgett (LB) fabrication of nanometer-precise, uniform PM6 and N2200 polymer films. Optimized solvent and spreading conditions yield controlled assembly of uniform and homogeneous mono- and multilayers. PM6 formed isotropic films with tangled coiled structures, while N2200 showed anisotropic domains with directional π-stacking and extended branch-like polymer chains. Nanomechanical analysis revealed a 35-40% increase in surface elasticity for multilayers versus monolayers. Surface potential measurements underlined a thickness-dependent transition from substrate-dominated electrostatics in monolayers to a bulk-like behavior in multilayers, while photoluminescence mapping confirms preservation of emissive functionality even down to a monolayer. Preliminary photoresponsivity tests with photoactive layers below 20 nm show a reproducible increase in short-circuit current density upon increasing the number of PM6 and N2200 layers from five to six each, as confirmed by measurements across multiple devices. This trend is attributed to an absorption cross section that scales with increasing layer thickness. Our results position the LB method as a robust platform for constructing ultrathin, structurally coherent, and electronically active polymer interfaces with nanometer-scale thickness control.

Background:In this study, we evaluated the effects of a combined exercise program incorporating a postural balance apparatus on the fall-related physical fitness and blood vessel elasticity of older women.Methods:The participants were 36 women aged 65 years or older who did not engage in regular exercise. They were randomly divided into an exercise group (n = 18) and a control group (n = 18). The exercise group underwent a combined exercise program for 12 weeks (60 minutes a day for 5 days a week), whereas the control group engaged in no physical activity or exercise during the 12 weeks. The combined exercise program consisted of aerobic exercise (such as step-ups and the short foot exercise), resistance exercises (such as heel raises, semi-squats, and weight-bearing closed-chain exercises), and joint mobility exercises (such as step-ups with pelvic floor muscle engagement, lower body stretching, and back stretching) to be performed on a postural balance apparatus, which provided an inclined and elastic surface to facilitate ankle dorsiflexion, joint mobility, and proprioceptive stimulation. The exercises were performed at a moderate intensity, maintaining a perceived exertion rating between 11 and 14, for 12 weeks. The outcome variables were measured through experimental procedures. The collected data were analyzed using means, standard deviations, and 2-way repeated measures analysis of variance.Results:We found a significant improvement in the range of motion for left ankle dorsiflexion in the lying and seated positions, as well as right ankle dorsiflexion in the lying, seated, and prone positions, in the exercise group compared to the control group (P < .05). Furthermore, the atherosclerosis left brachial–ankle pulse wave velocity, atherosclerosis right brachial–ankle pulse wave velocity, diastolic blood pressure, and heart rate significantly decreased in the exercise group compared to the control group (P < .05).Conclusions:These results confirmed that the 12-week apparatus-assisted combined exercise program, unlike conventional programs, effectively improves ankle dorsiflexion, vascular elasticity, and cardiovascular health in older women.

Rubber-based dental impression materials are widely used in prosthodontics due to their superior accuracy and dimensional stability; however, their susceptibility to microbial colonization poses both infection-control and material integrity concernsInitial bacterial adhesion is governed by physicochemical factors such as surface hydrophobicity, surface free energy, roughness, and salivary pellicle formation. Staphylococcus aureus demonstrates rapid adhesion to hydrophobic surfaces mediated by protein adhesins, whereas Pseudomonas aeruginosa exhibits strong persistence through biofilm formation on hydrophilic substrates. Beyond adhesion, both organisms contribute to material deterioration via the release of extracellular enzymes. Pseudomonas aeruginosa, in particular, produces elastase and other proteolytic enzymes capable of degrading polymeric chains, leading to alterations in surface integrity, elasticity, and dimensional stability. In contrast, Staphylococcus aureus exhibits comparatively moderate degradative potential through proteases and lipases. Conventional disinfection methods reduce planktonic bacterial load but are less effective against enzyme-producing biofilm communities. Emerging approaches, including antimicrobial and enzyme-resistant elastomers, offer promising strategies to mitigate both microbial contamination and biodegradation Keywords: Dental impression materials; Staphylococcus aureus; Pseudomonas aeruginosa; Bacterial adhesion; Enzymatic degradation; Biofilm formation

Effects of high-vibration elastic screen surface structure on motion characteristics and screening performance

The engine oil plays an important role in improving thermal efficiency in automobile engines by dissipating excess heat from the moving components. Recent advancements in thermal engineering have brought the concept of hybrid nanofluid as an effective approach to enhance thermal of conventional lubricants. In current investigation, a mathematical model has been developed to investigate thermal performance of couple stress-based hybrid nanofluid containing the copper oxide [Formula: see text], titanium oxide [Formula: see text] nanoparticles with engine oil [Formula: see text] base fluid. Unlike previous investigations that primarily discuss the hybrid nanofluid by neglecting the combine impact of nonlinear radiated effects and internal heat generation, this investigation simultaneously accounts these features to provide a comprehensive thermal model. The source of flow is linearly moving elastic surface. The solution methodology is based on famous numerical shooting scheme. Comparative thermal results are prepared for mono nanofluid [Formula: see text] and hybrid nanofluid [Formula: see text] The results show that the suspension of hybrid nanofluid significantly enhances the heat transfer features as compared to mono nanofluid. The developed model is effective for optimizing thermal management in automobile lubrication systems and control of industrial cooling systems.

The dynamic properties of spread and adsorbed layers of amyloid-like silk fibroin fibrils (ALF) differ significantly from the properties of native protein layers (RSF). In the former case, the dynamic dilational surface elasticity and the steady-state adsorbed amount are considerably lower than in the latter case. This high dynamic elasticity of RSF layers is close to that of the layers of solid nanoparticles and is provided by the spontaneous formation of various interconnected supramolecular structures at the interface. The ALF produced at elevated temperatures is also intertwined at the interface but does not form a continuous network. In this case, the layer properties are close to those of the layers of amyloid fibrils of globular proteins. If the ALF dispersion is purified from admixtures of unreacted protein molecules, the dynamic surface elasticity reaches about 140 mN/m, similar to the results for dispersions of amyloid fibrils of globular proteins. The admixtures of unreacted protein molecules of high surface activity significantly influence the dynamic surface properties participating in the self-assembly, thereby leading to a slight increase in the surface elasticity. At the same time, the ALF acts as an effective inhibitor of the formation of supramolecular structures in the surface layer for mixed systems. Under the influence of amyloid fibrils, neither the impurities nor the addition of native RSF lead to mechanical surface properties close to those of native fibroin systems.

In order to study the noise reduction performance of Porous Elastic Road Surface (PERS), the vibration noise and air pumping noise has been separated from the tire-road noise through the finite element numerical simulation method. The tire-road noise model among the tire, road and surface air has been constructed by coupling of acoustic waves. The characteristics of tire-road noise under the PERS, Porous Asphalt Concrete (PAC), and Asphalt Concrete (AC) pavements have been analyzed through the modelling. The tire-road noise has also been investigated through the noise field tests. The generating process, coupling characteristics, and noise reduction performance of the vibration noise and the pumping noise of PERS pavements has been revealed. The results show that the tire-road noise was mainly generated by the vibration noise under the vehicle speed below 80 km/h. The proportion of pumping noise gradually exceeds that of vibration noise under the vehicle speed greater than 90 km/h. And the pumping noise gradually played the major role in the tire-road noise, which also increased with the increasing of vehicle speed. Comparing with AC and PAC pavements, PERS pavement exhibited the obvious advantages in noise reduction. Additionally, the reliability of the tire-road noise model has been verified through the field noise tests. It is expected that this work will serve as a reference for future research on the mechanics of the generation of tire-road noise, and try to provided theoretical support for the application of PERS.

The bursting of surface bubbles can produce jet droplets and thus mediates the mass transfer across liquid–gas interfaces, which is ubiquitous over a wide range of natural and industrial processes. Though the bubble bursting jetting behavior in pure liquids has been well documented, how the widely existing particulates in liquids affect jet dynamics remains unclear. Here, we experimentally investigate the jet dynamics induced by bubble bursting at the suspension surfaces of submicrometer and micrometer particles with a mass concentration up to 200 g/L. We find that the submicrometer particles in liquids make the jet droplets faster and smaller, which are attributed to the influence of the particles on the viscosity and surface tension of the liquid phase. In contrast, in micrometer particle suspensions, the jet droplets become slower and larger and finally are completely suppressed as the particle concentration increases. By analyzing the influence of particles on the cavity collapse time, we deduce that the micrometer particles modify the jet dynamics by introducing extra surface effects of Marangoni stress or surface elasticity, as micrometer particles are easier to be collected to the bubble surface than submicrometer particles. These results promote our understanding of bubble bursting jetting in complex liquid systems and imply the multiscale hydrodynamic interaction between the particle of different scales and bursting bubbles, which deserves further studies.

This work presents a unified, size-aware study of the dynamic stability of submicrometer beams embedded in an elastic medium and subjected to combined static and harmonic axial loading. Timoshenko and Euler–Bernoulli beam formulations are considered while explicitly accounting for surface elasticity and residual surface stress to capture size-dependent mechanical behavior at the nano- to micrometer scales. The governing partial differential equations are projected onto trigonometric admissible functions via the Galerkin method and cast into extended Mathieu–Hill form, and instability boundaries are determined using Floquet–Lyapunov theory. Numerical results, obtained by integrating the resulting ordinary differential systems with a Runge–Kutta scheme (Gill coefficients), systematically quantify how beam model choice, anodic-alumina crystallographic orientation ([100] versus [111]), elastic foundation stiffness, and excitation frequency alter parametric-instability regions, providing direct guidance for the design and stability assessment of nanoscale structural elements.

Thermal and energy performance of hybrid aluminum nitride–alumina (AlN–Al2O3) suspension: A pathway toward enhanced stability and efficiency

Analysis of the stability of an immersed elastic surface using the method of regularized Stokeslets

This research examines the nonlinear dynamics of carbon nanotube-based nanobeams subjected to harmonic forcing, aiming to advance the design of high-performance athletic gear. The analysis accounts for geometric nonlinearities, damping from a viscoelastic substrate, and surface effects essential to creating lightweight yet robust components for items such as tennis rackets, golf clubs, and protective equipment. Given the elevated surface-to-volume ratio in nanomaterials, the study evaluates surface elasticity and residual stresses to improve shock absorption and energy dissipation. Equations of motion are formulated based on Euler-Bernoulli beam theory, discretized through the Galerkin approach employing trigonometric modes, and resolved via the method of multiple scales. Critical factors, including viscoelastic damping factors, crystal directions ([100] and [111]), and nonlinear geometry, are assessed for their impact on the primary resonance curve. Findings reveal that strategic adjustment of these variables can profoundly modify the frequency-amplitude behavior, allowing customized rigidity and attenuation suited to sporting needs. This work establishes a basis for engineering advanced nanomaterials in sports, harnessing nonlinear vibrations to enhance functionality, longevity, and user protection.

The impact behavior of droplets on heterogeneous hydrophilic-hydrophobic surfaces has significant research value for applications such as surface coating and inkjet printing. However, due to the nonuniform distribution of surface wettability, the mechanisms governing dynamic spreading during droplet impact remain unclear. Through systematic experiments, this study investigates the dynamic spreading behavior of droplets on flexible, heterogeneous surfaces with varying hydrophilic-hydrophobic properties under different Weber numbers, revealing how substrate flexibility modulates energy dissipation and contact line dynamics, thereby influencing the maximum spreading diameter. Building upon classical droplet spreading theory for rigid walls, a predictive model for the maximum spreading diameter of droplets on flexible, hydrophilic-hydrophobic heterogeneous surfaces is established. The model is optimized and validated using experimental data. This research provides theoretical support for the controlled deposition of droplets on heterogeneous, flexible surfaces. It offers an important reference for studying fluid-dynamic behavior on complex wettable surfaces.

In this paper we describe a technique to make a confined environment of variable stiffness that is suitable for high-resolution live-cell imaging. This versatile and adaptable technique enables cell confinement between soft elastic surfaces made from polyacrylamide gels. The two surfaces retain all their compatibility with multiple approaches to chemically couple adhesion proteins, and additional techniques like micropatterning and traction force microscopy. This method is thus well suited for measuring force production and migration of weakly adherent cells that struggle to migrate in traditional planar environments.

The influence of surface elasticity on the stress-strain state of a crack type III, which occurs under antiplane shear deformations of a linearly elastic body, is investigated. Me-chanical effects that arise near surfaces, particularly at the crack faces, are taken into ac-count using the Gurtin and Murdoch continuum surface-boundary model. Equilibrium condi-tions on the crack surface are formulated, as well as the relationship between surface and body stresses. Using these relationships, refined boundary conditions are written on the upper and lower faces of the crack, which are further analyzed using the methods of the theory of complex variable functions. As a result of this analysis, a first-order singular integro-differential equation with a Cauchy-type kernel is formulated. For its solution, the representa-tion of unknown functions in terms of Chebyshev polynomials of the first kind and the method of collocation on the nodes of these polynomials are used. The solution of the resulting system of linear algebraic equations allows to obtain the coefficients of the specified expansions. A formula for calculating the stress on the crack extension is found, which is expressed by an integral with a Cauchy type kernel. A comprehensive analysis of the peculiarities of the nu-merical implementation of the developed algorithm is carried out. It includes variations in the number of components in the expansions of unknown functions in Chebyshev polynomials and the number of nodes in Gauss quadrature formulas for calculating the specified integral. The behavior of the stress difference between the upper and lower crack faces as well as the dis-tribution of another stress component on the crack extension is graphically illustrated in the vicinity of the right tip. The dependence of these quantities on the values of the uniform shear stress specified on the crack edges is also illustrated. It is shown that the consideration of sur-face elasticity becomes especially noticeable when the crack length is less than a micrometer. Further decrease of this length leads to significant change of the character of the stress dis-tribution in the vicinity of the crack tip. In particular, the square root singularity of the stresses at the crack tips, which is characteristic for the classical crack model, disappears and the stresses at these tips become finite.

We explore the dynamical response of the free surface of an ultrasoft solid driven by a localized moving pressure disturbance. Experiments reveal a steady V-shaped wake analogous to a surface Mach wedge. A simple geometric argument provides a qualitative explanation consistent with observations. A theoretical framework combining elastodynamic, capillary, and gravitational effects yields a generalized dispersion relation that smoothly interpolates between Kelvin's theory of liquid interface wakes and Rayleigh's theory of elastic surface waves. Our analysis explains the observed Mach-like behavior quantitatively while also emphasizing how elastodynamic effects can generate effective damping through radiative leakage. Together, our experiments and theory reveal the existence of a new regime that bridges fluid and solid surface-wave physics, offering new routes for probing the dynamics of soft interfaces.

Iron oxides constitute an important class of materials, exhibiting a rich and intricate range of behaviors. Despite their significance, their structural and mechanical properties, particularly Hematite ($$\alpha$$-Fe$$\phantom{0}_2$$O$$\phantom{0}_3$$), have been scarcely investigated in the literature from a theoretical standpoint. At the same time, recent developments in machine learning for interatomic potentials have revolutionized computational materials science by enabling highly accurate and efficient simulations of atomic interactions. Traditional methods, such as density functional theory (DFT) and classical force fields, often struggle with high computational costs or lack the flexibility to generalize across diverse chemical environments. ML-based approaches, have emerged as powerful alternatives, learning complex potential energy surfaces from quantum-mechanical data. These models can achieve DFT accuracy at a fraction of the computational cost, facilitating large-scale molecular dynamics (MD) simulations. In this work, we present a graph neural network interatomic potential for hematite. The model was trained on datasets generated from DFT+U calculations to account for strong electronic correlations, using atomic configurations sampled across a wide range of temperatures and pressures. Our potential accurately reproduces fundamental material properties, including the elastic moduli, anisotropic elastic constants, vibrational frequencies, and surface energies. Furthermore, we demonstrate its transferability to other bulk iron oxides. This work enables large-scale molecular dynamics (MD) simulations of iron-based materials with ab initio accuracy at a computational cost comparable to that of classical potentials, opening new opportunities for investigating these complex systems.