Search Results (605)

The rapid advancement of information technology and pervasive use of electronic devices has exacerbated electromagnetic radiation pollution and interference, driving the demand for lightweight, flexible, and high-efficiency electromagnetic shielding materials in materials research. As a high-performance elastomer, thermoplastic polyurethane (TPU) possesses excellent elasticity, wear resistance, oil resistance and processability, making it promising for flexible electronics and wearable devices. However, pure TPU is electrically insulating and exhibits nearly no electromagnetic shielding capability, which requires conductive filler incorporation for functional modification. Herein, ternary TPU/MWCNT/BiFeO₃ composites were fabricated via solution blending and hot pressing, using multi-walled carbon nanotubes (MWCNTs) and bismuth ferrite (BiFeO₃) as conductive and dielectric fillers within the TPU matrix. The effects of filler content on the microstructure, thermal stability, mechanical properties and electromagnetic shielding performance of composites, together with the relevant mechanisms, were systematically studied. For the ternary TPU/MWCNT/BiFeO₃ system, the introduction of BiFeO₃ continuously increases the char residue rate of the composites to 16.01%, while accelerating the reaction process during the main thermal decomposition stage. The mechanical properties gradually deteriorate with the increase in BiFeO₃ content, and the composite with 5 wt% BiFeO₃ almost loses its elastomeric characteristics. The electromagnetic shielding effectiveness (SE) presents a trend of initial increase and subsequent decrease. The composite with 3 wt% BiFeO₃ exhibits the optimal shielding performance, with a 24.7% enhancement in total SE compared with the reference TPU/MWCNT composite containing 1% MWCNT. This improvement is attributed to the interfacial polarization and dipole polarization induced by the appropriate amount of BiFeO₃, which effectively strengthen the electromagnetic wave absorption loss capacity of the composites. Full article

Bread texture and flavor are largely governed by the development of its internal microstructure and the migration dynamics of water and volatile compounds. In this study, a bamboo shoot shell superfine powder/κ-carrageenan composite gel system (KCS) was developed, and the effects of different addition levels (0%, 5%, 10%, 15%, 20%) of KCS on bread performance, structure, and flavor were investigated. Compared with κ-carrageenan (KC), KCS formed a denser and more continuous composite network structure with higher elasticity, freeze–thaw stability, and thermal stability. Bread with KCS showed improved color, reduced hardness, and chewiness. Electronic nose and tongue indicated that KCS effectively suppressed the release of undesirable volatiles and taste-active substances. The addition of 10% KCS promoted the formation of a uniform fine honeycomb gluten network structure, inhibited starch retrogradation, and improved the thermal stability of bread. During storage (1–5 d), KCS reduced the water loss rate of bread, delayed the increase in hardness and chewiness, and maintained good springiness. Metabolomic analysis showed that KCS increased the precursors of small peptides involved in the Maillard reaction, thereby enriching flavor. KCS can effectively improve bread quality, enrich bread flavor, and delay aging, providing a new strategy for the high-value utilization of bamboo shoot processing by-products. Full article

Background: Exhaled volatile organic compounds (VOCs) may provide a non-invasive readout of biological changes in colorectal cancer (CRC). We characterized early postoperative changes in the exhaled volatilome after curative CRC surgery and explored a multivariable VOC signature associated with clinical state. Methods: In this prospective paired pilot study, breath samples were obtained from 38 patients before surgery (Before) and on postoperative day 10 (After) and from 44 healthy controls (Control). Proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) identified 61 informative volatile organic compound (VOC) features. Elastic Net-based stability selection with 1000 patient-grouped resampling iterations yielded a 16-feature panel. Pairwise univariate comparisons were performed with Benjamini–Hochberg false discovery rate (FDR) correction. Results: Five selected VOC features differed significantly between paired preoperative and postoperative samples. Two features (mass-to-charge ratio [m/z] 77.0576 and 103.074) no longer differed significantly from healthy controls postoperatively, whereas three (m/z 63.0157, 95.0534, and 101.05) remained significantly different. The highest discriminative performance was observed for After vs. Control (median ROC AUC = 0.811 [95% PR, 0.691–0.912]), followed by Before vs. Control (0.762 [0.629–0.869]) and Before vs. After (0.716 [0.567–0.823]). Conclusions: Measurable changes in the exhaled volatilome were observed on postoperative day 10 following curative colorectal cancer surgery, with heterogeneous patterns across individual VOC features and persistent differences from healthy controls. These findings should be interpreted as early postoperative volatilome remodeling rather than as evidence of tumor-specific metabolic normalization because the observed changes may reflect the combined influence of surgical trauma, postoperative recovery, and other biological and perioperative processes. The identified 16-feature multivariable VOC signature should therefore be regarded as exploratory and requires independent external validation. Further studies incorporating larger multicenter cohorts, serial sampling beyond the early postoperative period, appropriate non-oncological surgical control groups, and orthogonal chemical identification are required to determine the potential clinical relevance of longitudinal VOC patterns. Full article

Objective: This study aimed to evaluate the long-term degradation behavior, biostimulatory effects, and biocompatibility of a novel poly-L-lactic acid-block-polyethylene glycol/hyaluronic acid (PLLA–b–PEG/HA) composite filler for soft tissue augmentation. Methods: PLLA–b–PEG/HA microsphere properties were characterized via scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance hydrogen spectroscopy (¹H NMR), thermogravimetry (TG) and differential scanning calorimetry (DSC). A 104-week in vivo rabbit model was established to systematically observe filler degradation and tissue responses. Ultrasound monitoring, histological staining, ELISA and RT-PCR were performed to assess volumetric changes, inflammatory reactions and collagen synthesis-related signaling. Results: Physicochemical property tests demonstrated that PLLA–b–PEG retains the fundamental physicochemical properties of pristine PLLA while exhibiting enhanced hydrophilicity. B-ultrasound demonstrated a presented uniform in vivo distribution without displacement or diffusion over time, confirming steady and predictable degradation. SEM verified progressive morphological degradation and porous evolution of the microspheres. The filler induced a mild, balanced inflammatory microenvironment with early expression of both pro-inflammatory (IL-12, TNF-α) and anti-inflammatory (IL-4) cytokines, which resolved gradually over time. Sustained TGF-β upregulation persisted throughout the 104-week observation period, driving continuous neocollagenesis and prominent neoelastogenesis, thereby achieving favorable and long-term tissue remodeling with excellent biocompatibility. Conclusions: The PLLA–b–PEG/HA composite filler exhibits controllable degradation properties and homeostatic regulatory effects, along with outstanding long-term biosafety and tissue integration capacity. As an ideal biostimulatory filler for soft tissue augmentation, it can effectively facilitate the regeneration of high-quality functional extracellular matrix rich in collagen fibers and elastic fibers, and holds promising clinical prospects for natural and long-lasting soft tissue filling applications. Full article

Background and Objectives: Magnesium-based biomaterials are increasingly investigated due to their biodegradability, bone-like elastic modulus, and potential osteogenic properties. However, alloy composition may influence degradation behavior and local tissue response. This study aimed to assess and compare the local biocompatibility, degradation characteristics, and bone regenerative response induced by Mg-Zn-Mn-Ca and Mg-Nd-Y-Zr-Zn magnesium alloy powders. Materials and Methods: Two magnesium alloys were evaluated through physicochemical characterization, in vitro osteoblast cytocompatibility and antimicrobial assays, and in vivo testing in Sprague–Dawley rats. Standardized cylindrical defects were created in the medial femoral condyle and filled with either Mg-Nd-Y-Zr-Zn or Mg-Zn-Mn-Ca alloy powders, while untreated defects served as controls. Bone remodeling and defect healing were assessed by micro-computed tomography, allowing three-dimensional qualitative and quantitative evaluation of newly formed bone. Scanning electron microscopy was used to analyze surface morphology and degradation features, while histopathological examination assessed inflammation, osteogenesis, and tissue integration at the implant site. Results: Both magnesium alloy powders showed antimicrobial potency and elicited no cytotoxic effects in vitro, while animal studies revealed progressive biodegradation over time, associated with new bone formation within and around the defect area. Micro-CT analysis demonstrated active bone remodeling in experimental groups, with differences in bone distribution and defect-filling patterns between Mg-Nd-Y-Zr-Zn and Mg-Zn-Mn-Ca implants. SEM revealed alloy-specific degradation morphologies. Histological evaluation showed a moderate early inflammatory response that decreased at later time points, together with ongoing osteogenesis and favorable tissue integration. No severe local adverse reactions or persistent inflammation were observed. Conclusions: Both Mg-Nd-Y-Zr-Zn and Mg-Zn-Mn-Ca alloy powders were locally biocompatible and supported bone regeneration in a rat femoral condyle defect model. Differences in degradation behavior and tissue response emphasize the relevance of alloy composition in developing magnesium-based biomaterials for bone defect treatment. Full article

Ultraweak photon emission (UPE) provides a noninvasive optical signature of oxidative chemistry, but the relationship between infection-associated reactive oxygen species (ROS) and photon emission remains mechanistically uncertain. Here, we develop a multiscale framework linking pathogen dynamics, immune activation, signaling ROS, emission-relevant oxidative chemistry, chemiexcitation-capable intermediates, electronically excited molecular states, and wavelength-resolved UPE. Chemiexcitation is represented as incoherent Lindblad pumping, allowing stochastic oxidative reactions to populate molecular excited states without assuming coherent ROS-driven optical excitation. The model was evaluated using literature-constrained oxidative inputs for healthy, severe COVID-19, and sepsis conditions, together with Latin Hypercube uncertainty propagation, Sobol sensitivity analysis, fixed-ROS counterfactual testing, spectral robustness analysis, and a pathway-level PMA/DPI intervention consistency test. Two admissible oxidative-to-photon mappings produced sharply different quantitative predictions from the same clinical ROS inputs. Under a high-gain structure, 9.01-fold and 13.86-fold oxidative increases produced 42.21-fold and 89.02-fold increases in peak UPE, whereas a saturating structure compressed the same inputs to 1.445-fold and 1.450-fold. Local elasticity remained near 1.7 under the high-gain mapping but declined to 0.011 and 0.005 at the COVID-19 and sepsis inputs under the saturating mapping. At fixed ROS, downstream parameter uncertainty produced more than a 200-fold spread in predicted UPE under the high-gain structure. Sobol analysis identified the saturation scale, emission-relevant oxidative lifetime, and signaling-to-emission conversion as the dominant contributors to output variance. In a pathway-level consistency test, a subset of high-gain realizations reproduced the reported DPI/PMA residual-UPE interval under physically admissible residual oxidative drive, whereas none of the sampled saturating realizations did. The model also predicted a progressive redistribution of spectral intensity toward longer wavelengths with increasing oxidative burden, although absolute spectral centroids remained dependent on the assumed spectral representation and emitter weighting. These results show that current ROS measurements constrain the direction of the UPE response more strongly than its quantitative magnitude and do not identify a unique universal ROS-to-UPE transfer function. Full article

An acylation reaction was performed on the crystalline surface of cellulose in a composite consisting of microfibrillated cellulose (MFC) and hydroxyapatite (HAP) with an inorganic weight fraction of 68%. The composite was acylated using acetic anhydride, propanoic anhydride, and butanoic anhydride in pyridine in the presence of potassium carbonate at 120 °C for 1 h. The formation of ester linkages was confirmed by infrared spectroscopy, and X-ray diffraction analysis showed that the crystalline structure of cellulose was retained after acylation. From the intensity of the carbonyl stretching vibration in the infrared spectra, the degree of substitution of the acetylated sample was estimated to be approximately 0.2. The acylated MFC–HAP composites were uniaxially hot-pressed at 120 °C and 300 MPa, and the resulting molded specimens were subjected to three-point bending tests. A yield point appeared at a bending strain of 1.1–1.4%, followed by plastic deformation and final fracture, indicating that they exhibited ductile fracture. The elastic moduli were 5.9 GPa (acetyl), 7.6 GPa (propanoyl), 7.4 GPa (butanoyl), 3.6 GPa (hexanoyl), and 7.1 GPa (before acylation), indicating that acyl groups with medium chain lengths did not reduce the rigidity of the composites. When the molded specimens were immersed in water at room temperature for 24 h, the water absorption ratios were 29% (acetyl), 24% (propanoyl), 17% (butanoyl), and 18% (hexanoyl), demonstrating that water resistance improved with increasing acyl chain length. In summary, propanoylation and butanoylation improved the water resistance of the composites without compromising their rigidity in the dry state. Full article

Elastic scattering angular distributions of ¹⁷Ne + ²⁸Si at $E_{\mathrm{lab}}=22.4$ MeV/u and ¹⁵O + ²⁸Si at $E_{\mathrm{lab}}=18.2$ MeV/u, well above the Coulomb barrier ($E_{\mathrm{cm}}/V_{\mathrm{B}}=9.7$ and $8.2$, respectively), have been measured at the HIRFL–RIBLL facility in Lanzhou. Time of flight–$\Delta E$ (TOF–$\Delta E$) beam identification, PPAC-based trajectory tracking, and a target–detector integrated DSSD telescope were employed for event-by-event reconstruction of scattering angles and particle identification. Detection efficiencies and solid angles were evaluated and corrected by means of Geant4 simulations. Theoretically, the real parts of the optical potentials were calculated within a double-folding model using the density-dependent BDM3Y1–Paris effective interaction, while the imaginary parts were taken as Woods–Saxon forms and adjusted by ${\chi }^2$ fits to the data using the SFRESCO code. ¹⁷Ne has a larger matter distribution than ¹⁵O. However, once mass scaling is removed, the real potential remains essentially unchanged, indicating the structural effects are not encoded in the real part. At the same time, a substantially deeper imaginary potential is required for the ¹⁷Ne + ²⁸Si system, pointing to stronger absorption and coupling effects. A further analysis in terms of the reduced distance of closest approach shows that both the strong-absorption distance $d_{\mathrm{S}}$ and the effective coupling range $\Delta d$ are larger for ¹⁷Ne than for ¹⁵O, whereas the Coulomb barrier height $V_{\mathrm{B}}$ follows the known systematics and is insensitive to structural differences. These findings provide reaction-based evidence that the more diffuse and weakly bound structure of ¹⁷Ne has a pronounced impact on the scattering dynamics on a light- to medium-mass target. Full article

Bolted flange joints are critical load-bearing connection components of complex mechanical equipment, whose service performance is dominated by the coupled evolution of bolt preload relaxation and interfacial stiffness degradation under long-term cyclic combined loads. Under cyclic transverse excitation, the contact interfaces experience successive full-stick, partial microslip and macroslip states, accompanied by embedding, creep and friction-induced wear, resulting in time-varying preload attenuation and the continuous degradation of joint mechanical properties. Distinguishing preload relaxation without nut rotation from rotational self-loosening is essential for revealing multi-bolt flange degradation mechanisms. This paper presents a systematic review of physics-driven constitutive modeling and degradation characterization of bolted flange connections. A unified classification framework for joint interface models is established, covering static friction models; velocity-dependent dynamic friction models; hysteresis stick–slip models, represented by the four-parameter Iwan model and Valanis endochronic model; and reduced-order equivalent joint models. The inherent differences between the Dahl model and LuGre model regarding the Stribeck velocity–friction characteristics are clarified. The representative models are comprehensively evaluated from the perspectives of physical interpretability, hysteresis reproduction accuracy, preload–degradation correlation and engineering applicability. A further comparative analysis is conducted of parameter identification bottlenecks of the Iwan, LuGre and Valanis models, focusing on multi-solution risk, anti-noise robustness and cross-working-condition transferability. Compared with single-bolt lap specimens, multi-bolt annular flanges exhibit prominent inter-bolt elastic interaction, circumferential contact pressure non-uniformity and local-to-global chain-reaction degradation behaviors. The common experimental test-beds and sensing techniques for joint degradation monitoring are summarized, and the measurement limitations, including sensor drift, synchronization error and installation constraints, and their influences on model parameter identification, are discussed. The existing machine-learning, digital-twin and physics-informed modeling applications for bolted joints are briefly outlined. Finally, this review summarizes the existing research consensus, unresolved contradictions and open research challenges. Special attention is paid to the limitations of existing time-variant Iwan-type models for multi-bolt flange degradation. Potential future research directions include multi-channel synchronous sensing matching time-varying constitutive models, quantification of inter-bolt load redistribution, and robust identification strategies under noisy experimental data. Full article

Additive manufacturing provides a fabrication route for electrode components with controlled macrostructure; however, printable carbon inks that also incorporate oxygen reduction reaction active precursors remain underdeveloped. Here, XC-72 carbon was combined with selected metal precursors to prepare N–C, Fe–N–C, and Pt-containing carbon ink formulations for direct ink writing. The precursor mixtures were incorporated into a polyurethane-based matrix, pyrolyzed at 900 °C, and characterized using X-ray diffraction, oscillatory rheology, rotating ring-disk electrode measurements, Brunauer–Emmett–Teller surface-area analysis, and scanning electron microscopy. XRD confirmed retention of carbon diffraction features and the formation of metal-containing crystalline phases after pyrolysis. Oscillatory rheology showed storage moduli exceeding loss moduli for the tested formulations, indicating elastic-dominant behavior suitable for shape retention during printing. For the PGM-free formulations, incorporation of nitrogen and iron precursors improved ORR onset potential, half-wave potential, limiting current density, and electron-transfer selectivity relative to the carbon control. BET analysis showed a decrease in accessible surface area after precursor incorporation, consistent with partial pore blocking or structural modification during pyrolysis. These results establish a printable formulation platform for ORR-active carbon-based inks, while future work is required to isolate the effects of printed architecture, pore hierarchy, and durability under fuel-cell operating conditions. Full article

TiB₂ ceramics have a wide range of applications due to their exceptional properties. However, high relative density must be achieved to enable their use in cutting tools, wear-resistant components, body armor, and extreme environment applications. In this study, high-purity TiB₂ powders with hexagonal platelet-like morphology were synthesized through boro/carbothermal reduction reactions under Ar flow. In-house synthesized and commercial TiB₂ powders were consolidated via spark plasma sintering. The effects of oxygen content, sintering temperature, and hold time on the microstructure, elastic and mechanical properties of monolithic TiB₂ ceramics were investigated. The highest relative density of 99.43%, elastic modulus of 541 GPa, and Vickers microhardness of 40.35 GPa were achieved at 1750 °C for a hold time of 45 min. The exceptional properties, among the highest achieved for spark plasma sintered monolithic TiB₂, are attributable to preferential kinetic conditions and the powder’s morphology. Full article

During long-term service, asphalt pavements undergo environmental stress and ageing, which cause cracking, rutting, and other distresses and raise maintenance costs. Polyurethane (PU) has high mechanical strength, elastic recovery, and ageing resistance due to its unique molecular structure. As an asphalt modifier, PU has been reported to improve high-temperature stability, moisture resistance, and durability. However, PU and asphalt differ greatly in polarity, density, viscosity, and phase structure, and these differences often lead to segregation and phase separation. The prepolymer method can mitigate these compatibility limitations by adjusting molecular weight, terminal-group activity, and soft/hard segment ratio before dispersion, chain extension, crosslinking, and post-curing in asphalt, resulting in better compatibility and more controllable processing. This review discusses PU soft/hard segment structures, asphalt composition, prepolymer synthesis and curing, microstructural evolution, pavement performance, storage stability, and use in other systems to clarify modification mechanisms and potential applications. This critical review aims to clarify material–reaction–process–performance relationships within the prepolymer route, with scope limited to molecular design, preparation mechanisms, performance, storage stability, and representative engineering applications. Future work should consider real service conditions and build multiscale evaluation frameworks that jointly optimise prepolymer design, processing, storage stability, and pavement performance, helping translate laboratory findings into low-carbon, long-life road materials that can be produced at scale. Full article

Classical hydrodynamic lubrication studies of journal bearings routinely invoke two simplifying assumptions: the axially rigid–straight journal assumption and the structure–lubrication decoupling assumption. For marine water-lubricated stern bearings, propeller overhung loading induces non-negligible shaft deflection across the bearing length, and the multi-support shafting makes the stern-bearing reaction force impossible to determine from rigid-body statics alone. Both assumptions must be removed within a single analysis framework. This study develops a coupled lubrication–rotor framework that combines a two-dimensional steady Reynolds solver with groove masking, a Winkler elastic liner, and a ROSS-based Timoshenko rotor finite element model through bidirectional reaction-force–tilt feedback. A normalised axial load distribution indicator $I_w\left(z\right)$, defined from the axial film-pressure profile, is introduced as a scalar boundary quantity linking the elastohydrodynamic lubrication solution to downstream wear evolution models. Condition decomposition and open-loop tilt sweeps show that the coupled-convergence tilt reduces $h_{min}$ by 65.7%, raises $p_{max}$ by 84.5%, and shifts the axial reaction-force distribution and $I_w\left(z\right)$ peak toward the stern end. Axial non-uniformity intensifies monotonically with the increase in tilt angle, and beyond a threshold tilt, the HD/EHL solver no longer converges for a hard phenolic liner, establishing the applicability upper bound of the framework. Full article

To address the insufficient bearing capacity of existing slab culverts under increased fill heights in highway widening projects, a reinforcement method integrating an additional deck slab with a grouted steel pipe pile-supported composite foundation is proposed. A segmented elastic foundation beam model is developed to derive the analytical solution for slab deflection and calculate the load acting on the culvert roof. A three-dimensional finite element model is established in Abaqus, in which the soil is modeled using the Mohr–Coulomb elastoplastic constitutive model to investigate the effects of pile arrangement, pile diameter, pile length, pile spacing, and fill height on reinforcement performance. The results show that culvert displacement and stress decrease with reduced pile spacing and increased pile diameter and pile length, while the best reinforcement performance among the investigated cases is achieved when the piles extend 4 m below the culvert base slab Field tests from the Beijing–Hong Kong–Macao Expressway widening project demonstrate the applicability of the proposed reinforcement method and show that pressure grouting increases the coefficient of subgrade reaction by 7–10%. Based on theoretical and field investigations, recommended reinforcement parameters are proposed for a representative culvert. The proposed method provides an efficient solution for culvert reinforcement in highway widening projects. Full article

This study addresses the significant increase in gas content and gas pressure caused by the rising proportion of high gas, low-permeability coal seams under high geostress conditions. This problem not only limits the efficient extraction of coalbed methane (CBM) but also poses a serious threat to mining safety. To overcome this challenge, a novel water-based ultrasonic cavitation-enhanced coalbed methane recovery (WUC-ECBM) is proposed. A self-developed multimodal ultrasonic cavitation reaction system is used to treat coal samples at different cavitation power levels (0–1100 W). Mechanical tests are then performed, and the damage evolution process is synchronously characterised using a multichannel acoustic emission monitoring system. Permeability tests are also conducted to evaluate the effect of ultrasonic cavitation on coal seepage performance. The results show that ultrasonic cavitation systematically alters the mechanical behaviour of coal, driving the evolution from microstructural modification to macroscopic mechanical response. The compressive strength decreased by up to 53.71%, and the elastic modulus fell to 1.34 GPa, indicating a marked reduction in coal stiffness. The cumulative acoustic emission energy decreased to 0.77 × 10⁶ mV·ms, demonstrating that ultrasonic cavitation promoted the initiation, propagation, and coalescence of internal microcracks, thereby accelerating damage evolution from microscale to macroscale. A progressive failure mechanism, characterised by primary cavitation-induced damage followed by secondary loading-induced damage, is ultimately formed. In addition, ultrasonic cavitation significantly enhanced coal permeability, with a maximum increase of 504.22%. These findings provide a theoretical basis for the further development of WUC-ECBM and for the efficient extraction of CBM. Full article