A tuning-fork-based multi-sensor for simultaneous real-time determination of surface mass density and elastic modulus in thin-film coatings

Drying cellulose nanofiber (CNF)-based filaments remains a challenge in scalable production due to the strong water affinity of CNFs and the risk of thermal degradation. In this study, we investigate the structural and mechanical effects of thermal drying at 20, 60, 105, and 160°C on TEMPO-mediated oxidized CNF (TCNF) filaments to determine the optimal drying conditions. Mechanical testing revealed an initial decline in elastic modulus and tensile strength from 20°C to 105°C, followed by a pronounced increase at 160°C, reaching values comparable to those of individual CNFs. Spectroscopic and diffraction analyses (FTIR, XRD) showed a progressive increase in carbonyl content with drying temperature and a moderate decrease in crystallinity indices, while crystal size in the [200] direction increased. SEM and AFM imaging confirmed densification and surface rearrangement at elevated temperatures. These results indicated a dual effect of drying: Moderate heating degraded mechanical performance due to structural disruption, whereas high-temperature treatment enhanced inter-fibril bonding and co-crystallization, leading to superior strength. However, yellowing and partial chemical transformation began at 105°C, suggesting a narrow window between beneficial densification and early degradation. Our findings offer insights into balancing structural integrity and production efficiency for robust, bio-based filament manufacturing.

Supercritical CO2-foamed hierarchically porous PLA/PBS-based scaffold for advanced bone regeneration.

Tailoring network structures of water-in-Oleogel emulsions by modulating oil-to-water ratios for the fabrication of croissants: Effects on rheological properties and final product texture.

Effective elastic modulus of 3D printed plastic 2D and 3D infill patterns

Optimal integration of lignin nanoparticles and whey protein distinctively stabilizes high internal phase pickering emulsions for multiple environmental resistances.

High-pressure treatment unlocks the emulsification potential of Desmodesmus protein extract for stable high internal phase emulsions.

Phase stability and mechanical properties of novel metastable Ti-Zr-Ta medium entropy alloys with low elastic modulus for biomedical applications

Mechanical characterization and visco-hyperelastic modeling of epithelial cells: Pressure-rate dependency of the apparent elastic modulus

The influence of the chemical nature of functional groups immobilized on the surface of silica nanoparticles on the physicochemical and mechanical properties of epoxy composites has been examined. Our work was formed on the basis of the assumption about the high role of the nature of the filler surface in the formation of the mechanical properties of polyepoxide. Modification of nanosilica with amino-groups (–NH2) should contribute to improving the characteristics of the composite due to the reactive affinity for epoxy and amine fragments of the matrix. In contrast, methyl groups (–CH?) should increase compatibility with the organic phase (oleophilicity), but due to chemical inertness, reduce the ability to interact in the polymer network. It was experimentally found that the introduction of 1–4 wt. % of unmodified nanosilica leads to a decrease in compressive strength, a decrease in chemical stability in acetone and an increase in the brittleness of the composite. At the same time, the indicators of shrinkage, thermal stability and resistance to an oxidizing environment remained unchanged or improved slightly. Modification of silica nanoparticles with methyl groups (at filling of 1–2 wt. %) provided partial recovery of compressive strength, increased thermal resistance and plasticity of the composite, but did not provide a significant improvement in solution stability or reduction in shrinkage. The most pronounced positive effects were achieved when using amino-nanosilica (modified with amino groups): a significant increase in compressive strength was observed to the level or higher than that of the unfilled resin, an increase in the elastic modulus, as well as a significant improvement in resistance to aggressive environments, fire resistance and reduction in shrinkage. Microscopic studies (optical microscopy, scanning electron microscopy, atomic force microscopy) confirmed that the introduction of unmodified nanofiller causes a decrease in transparency, the appearance of agglomerates and zones of heterogeneity. On the contrary, functionalization, especially with amino groups, provides a more homogeneous distribution of particles in the polymer matrix. The results obtained confirm the key role of the physicochemical properties of the nanosilica surface in the processes of structure formation of epoxy composites. Thus, optimal modification of the filler surface with chemically active groups opens up opportunities for targeted control of the properties of composites.

Oriental sweetgum balsam or Storax oil (Styrax liquidus) naturally exudes from wounds made on the tree trunk of Liquidambar orientalis. It is a natural material with antibacterial, antimicrobial, antitumor, and antioxidant properties. In traditional folk medicine, it has long been used in the treatment of gastric and skin diseases, therefore it is a good candidate for wound care applications. Electrospinning offers a platform to combine storax oil with poly(ε-caprolactone) (PCL) fibers together with hydrophilic absorbent polysaccharides. In this study, a single-step fabrication of flexible, lightweight, fibrous membranes was achieved which combined compatible formulations of PCL, storax oil, and either sodium alginate or chitosan as absorbent additives. PCL–Styrax–Chitosan and PCL–Styrax–Alginate membranes were compared to assess their morphology, surface wettability, and mechanical properties, with a focus on achieving homogeneous oil distribution and suitable exudate management through the absorbents. Scanning electron microscopy images revealed relatively uniform fibrous structures for PCL–Styrax and PCL–Styrax–Chitosan combinations, whereas alginate led to partially fused fibers. Hydrophilicity increased significantly with the addition of chitosan or alginate. Mechanical testing showed that chitosan improved flexibility and yielded an elastic modulus very close to skin elasticity, while alginate sharply increased the stiffness. In conclusion, PCL–Styrax–Chitosan membranes may prove to be a promising functional wound dressing opportunity that integrates a traditionally used natural balsam with favorable functions. Furthermore, the fiber morphology, wettability, mechanical strength and flexibility of the membranes are also suitable for this purpose. Future work should address storax oil release kinetics and membrane handling features as wound dressing, prior to in vitro and in vivo wound-healing evaluations.

Plantar skin is a highly specialised tissue which protects the foot from injuries and adapts to external stresses. However, it can be subjected to diabetic plantar ulcers, which are among the most difficult and costly wounds to treat. Although this is a crucial topic, few studies have focused on the mechanical properties of foot skin and how disease alters them. In this context, this work aims to fully describe the mechanical behavior of plantar skin through experiments and constitutive analysis. Different experimental tests (failure tensile tests, unconfined compression at different strain rates, stress relaxation tests) were conducted on human plantar skin samples cut along the posterior-anterior (PA), lateral-medial (LM), and cranial-caudal (CC) directions. Then, experimental results were used to identify, through an inverse analysis, the parameters of the anisotropic visco-hyperelastic constitutive model adopted to describe the skin's mechanical response. Plantar skin's non-linear, anisotropic, and time-dependent behavior, with differences between the anterior and posterior foot's regions. In addition, the constitutive model adopted is able to capture the mechanical behavior of the plantar skin Failure tensile tests showed that PA directions exhibited higher elastic modulus than LM directions in both posterior (22.05 vs 12.91MPa) and anterior (17.39 vs 12.82MPa) regions, while the unconfined compression tests revealed that compressive elastic moduli in the posterior region increased with increasing strain rates. The proposed model provides new insights into the mechanics of plantar skin, being a valuable tool for applications such as diagnosing skin diseases and developing skin substitutes.

The mechanical properties of materials, e.g., elastic modulus and hardness, are important for many engineering applications. Here, we introduce a hierarchically ordered structure (HOS) polymer system that exhibits exceptionally large, reversible changes in mechanical behavior upon electrochemical lithiation and delithiation. Full lithiation of the HOS polymer induces a substantial mechanical transition from polymer-like to metal-like attributes, yielding a 10-fold increase in elastic modulus and a 3-fold increase in hardness, with values comparable to those of aluminum. Upon removal of Li+ ions, the elastic modulus and hardness return to nearly pristine polymer levels, and this transformation remains highly repeatable over many electrochemical cycles. Reversible transitions between polymer-like and metal-like mechanical behaviors offer a new pathway for engineering materials for applications that require tunable mechanical properties, such as soft robotics and stimuli-responsive systems.

Poly(ethylene glycol)-based ultrathin films were prepared using hydrazide-poly(ethylene glycol)12-hydrazide (HZ-PEG-HZ) and 4-[[4,6-bis(4-formylphenoxy)-1,3,5-triazin-2-yl]oxy]benzaldehyde (TOB) at the air/dimethyl sulfoxide (DMSO) interface via interfacial polymerization (IP). The resulting ultrathin PEG-TOB films exhibited asymmetric properties, with lower wettability and roughness on the air side (AS) compared to those on the DMSO side (DS). X-ray photoelectron spectroscopy (XPS) results indicate a higher PEG content on the DS. The mechanical properties of the films were studied by atomic force microscopy (AFM) nanoindentation mapping using small (radius, R = 10 nm) and large (R = 29 nm) tips. The AS has a higher elastic modulus than the DS in both air and water. These asymmetries are attributed to preferential enrichment of hydrophobic aromatic groups on the AS and greater exposure of hydrophilic PEG chains on the DS during IP. Additionally, a higher elastic modulus was observed with the large tip in air at small indentations (less than 10 nm), attributed to contact stiffening due to the formation of an interface region upon compression. Furthermore, due to the substrate effect, the elastic modulus increased markedly at larger indentations. The present study provides a new understanding of the asymmetric mechanical properties of ultrathin interfacial films, improving the design of functional thin films.

This study evaluated the incorporation of epigallocatechin-3-gallate (EGCG)-loaded poly(lactide-co-glycolide) (PLGA) microparticles into a two-step etch-and-rinse adhesive and their effects on physicochemical properties and EGCG release. EGCG was added to Single Bond 2 either directly (0.01% and 0.1% w/w) or encapsulated in PLGA 50:50 or 75:25 microparticles (0.5%-2% w/w). Cumulative release was measured by UV-Vis spectrophotometry. Degree of conversion (DC) was analyzed by Fourier transform infrared spectroscopy; flexural strength and elastic modulus (E) were tested in three-point bending; and water sorption (WS) and solubility (SL) were evaluated following ISO standards (n=10). Microtensile bond strength (TBS) was tested after 24h, 6, and 12 months. Data were analyzed by anova with significance set at p<0.05. PLGA 50:50/EGCG at 1% showed the highest release, reaching 77.30µg. No significant differences were found in DC, E, WS, and SL among the groups. Bond strengths remained stable in all experimental groups after 6 and 12 months, except for the control. Incorporating 1% EGCG-loaded PLGA 50:50 microparticles into Single Bond 2 may represent a promising strategy for controlled release without compromising physicochemical or mechanical properties.

Diabetic foot is a prevalent and severe complication among diabetic patients, usually caused by sensory neuropathy and chronic mechanical stress overload. The structural characteristics of the tetrakaidecahedron porous structure are applied to insoles to optimize plantar pressure distribution, thereby minimizing abnormal plantar pressure in diabetic feet. Integrating plantar pressure zoning, finite element analysis, Grasshopper parametric modeling, and 3D printing technology, a customized pressure-relief insole for diabetic feet has been designed and validated using static standing plantar-pressure measurements. The insole employs a porous structure with adjustable porosity and specified regional elastic modulus to achieve customized plantar pressure relief. The designed insole (NPSI) increases the plantar contact area by approximately 30 % and reduces peak contact pressure by over 47 % in the high-pressure regions of M and H zones. The method proposed in this study effectively customizes pressure-relief insoles for diabetic feet, reducing the incidence and progression of diabetic foot ulcers. This approach is also applicable to the design of other assistive medical devices that require specific support and pressure relief.

The rectus femoris (RF) tendon may be an option for combined anterior cruciate ligament (ACL) and anterolateral (AL) reconstruction utilizing a double-stranded (DRF) tendon for the ACL and a single-stranded tendon (SRF) for AL reinforcement; however, biomechanical data remain limited. This study aimed to biomechanically assess the DRF for ACL reconstruction using a patellar tendon (PT) graft and the SRF for AL reconstruction using an iliotibial band (ITB) graft. The hypothesis was that the biomechanical properties of the DRF graft would not differ from those of the PT graft, and the SRF graft would not differ from the ITB graft. Controlled laboratory study. Eight fresh-frozen human knees were used: 2 male and 6 female, with a mean age of 49 years (range, 36-64 years). Each knee produced 4 grafts: DRF, SRF, PT, and ITB. Each graft was mounted in a materials test machine. The cross-sectional area was measured using alginate molding. After 10 preconditioning cycles to 250 N, each specimen was extended to failure at 100 mm/min. The Friedman test assessed differences between the 4 graft types using matched samples. The Dunn multiple-comparison test was used to examine differences among graft types. The ultimate strengths (N) of the grafts were as follows: DRF, 1978 ± 338; SRF, 1445 ± 584; PT, 1824 ± 557; ITB, 819 ± 268 (DRF and PT >ITB; P < .01). The elastic moduli (MPa) were as follows: DRF, 272 ± 59; SRF, 617 ± 153; PT, 318 ± 90; ITB, 631 ±4 31 (DRF and PT<SRF; P < .05). The ultimate tensile stresses (MPa) were as follows: DRF, 51 ± 12; SRF, 89 ± 28; PT, 62 ± 19; ITB, 56 ± 24 (SRF > DRF; P < .05). As hypothesized, the DRF graft exhibits mechanical properties that do not differ from those of the PT graft. Likewise, the SRF graft showed biomechanical properties that do not differ from those of the ITB graft. Therefore, this study supports the use of the RF graft for combined ACL and AL (anterolateral ligament or lateral extra-articular tenodesis) reconstruction. The RF tendon graft is harvested before being merged with other layers, resulting in a longer graft (mean, 273 mm) suitable for folding. This does not create a full-thickness defect through the quadriceps. This approach allows combined ACL + AL reconstruction techniques and additional graft tissue for fixation.

Composites based on rPE and OPEFB waste are considered sustainable materials. However, their performance is limited by hydrophobic–hydrophilic incompatibility, which weakens interfacial adhesion. This study investigated the atmospheric-pressure air plasma treatment of rPE to enhance its compatibility with OPEFB fibers and evaluated its role as a compatibilizer. Atmospheric plasma treatment for 120 s introduced oxygen-containing groups onto the rPE surface, as evidenced by C-O and OH peaks in the FTIR spectra and the higher O/C ratio in the XPS analysis. Consequently, the water contact angle decreased, reducing the difference in surface tension between rPE and OPEFB from 45.61% to 7.80%. Composites containing 20 wt.% OPEFB were fabricated by varying the proportion of untreated rPE with p-rPE. All p-rPE-based composites exhibited fewer interfacial voids than untreated rPE composites, indicating improved fiber–matrix adhesion. The tensile strength and elastic modulus increased with the p-rPE content, whereas the elongation at break remained higher than that of the untreated composite. Therefore, p-rPE shows potential as a compatibilizer, enabling agricultural and plastic waste value enhancement.

Frequent large-scale construction projects have rendered subway box structures vulnerable to displacements. This study examined the adequacy of foundation reinforcement for a subway box structure exhibiting displacement behavior. A displacement function was derived from the optical leveling data, and a three-dimensional numerical analysis was performed by applying the computed subgrade elastic modulus as a boundary condition. The analysis produced estimates of uplift and subsidence at the nodes along both the transverse and longitudinal directions of the structure. To determine the required amount of reinforcement (grouting volume), the nodal reinforcement depth obtained from the analysis was applied to a grid-based volumetric calculation method. The nodal intervals were subdivided to the maximum feasible extent, and rectangular grids with sufficient resolution were established to ensure accurate reinforcement-volume calculation. The reinforcement volumes estimated through the numerical analysis were compared with actual field values to assess the adequacy of the foundation reinforcement. Some differences were observed, which were attributed to field constraints that prevented reinforcements at certain required locations. Based on these findings, additional reinforcements can be applied at the analytically identified locations to ensure the structural safety of the subway box structure.

ABSTRACT To investigate void effects on cemented tailings backfill (CTB), this study combined uniaxial compression tests with particle flow simulations to analyse mechanical properties, energy evolution, and crack propagation. Specimens included single-void (5, 6, 8 mm) and double-void types with varying arrangement angles (0°, 45°, 90°). Voids significantly weakened the backfill: single-void peak strength decreased linearly by 7.4%–21.6% with increasing diameter, and elastic modulus dropped by 22.4%–55.3%. Among double-void specimens, the 90° vertical alignment exhibited the best performance, with strength 15% higher than the 8 mm single-void sample, indicating that vertical alignment optimises stress superposition and delays crack propagation. Energy analysis revealed altered storage–dissipation patterns: double-void specimens absorbed 11.2% more energy at peak, with post-peak release dominated by dissipated energy. Numerical simulations showed cracks initiating from tensile stress concentrations around voids and propagating obliquely at 45°. Damage evolution followed a Weibull distribution, and the 90° aligned specimen accumulated damage 30% slower. These findings support mine backfill design and defect repair by highlighting the role of void geometry in energy dissipation and stress field optimisation.