Search Results (2,313)

The effective utilization of recycled concrete powder remains a key challenge for sustainable construction. In this study, carbonated recycled concrete powder (CRCP) was applied to replace cement at levels of 4–16% in Portland cement–fly ash (OPC-FA) systems, and its effects on fresh properties, hydration behavior, shrinkage, pore structure, and mechanical performance were systematically investigated. The incorporation of CRCP reduced flowability and accelerated setting, while slightly advancing and enhancing the main hydration peak at 4–8% replacement, accompanied by higher CH at early ages and increased C–S–H formation at later stages. More significantly, the addition of CRCP substantially decreased both autogenous and drying shrinkage, achieving reductions in the ranges of 6.0–21.4% and 3.2–24.1%, respectively. This improvement is primarily attributed to the elevated internal relative humidity and the lowered capillary pressure within the system. In addition, the mechanical properties exhibited a clear optimum with the addition of 8% CRCP, where the 28 d compressive strength and flexural strengths increased by 16.3% and 4.0%, respectively. Further analysis indicates that this improvement is associated with a higher fraction of high-modulus regions and an increase in average elastic modulus from 23.89 GPa to 27.42 GPa, reflecting a denser microstructure. These results demonstrate that CRCP can effectively regulate hydration and microstructure, providing a feasible approach for improving dimensional stability and mechanical performance while enabling the value-added utilization of recycled concrete powder. Full article

Coal masses with well-developed cleats exhibit pronounced heterogeneity and anisotropy, and obtaining intact cores for mechanical testing remains a persistent challenge in engineering practice. Conventional assessments using the Hoek-Brown (HB) criterion rely heavily on empirical geological indices and cannot establish a quantitative correlation between cleat characteristics and rock mass parameters, thereby leading to low accuracy and efficiency in strength evaluation. In this study, numerical coal models are established using the discrete element method (DEM) combined with laboratory mechanical tests, and a series of uniaxial and triaxial compression simulations are conducted. Results reveal that cleat intensity is negatively correlated with uniaxial compressive strength and peak strain, while matrix stiffness and intermediate principal stress positively affect the elastic modulus and strength of coal; the intrinsic mechanical parameters of cleats exert a limited influence on the macroscopic mechanical behavior. A linear correlation between 2D cleat areal density P21 and 3D intensity P32 is verified, and a prediction model for HB parameters m and s based on cleat features is developed. The proposed method only requires profile cleat statistics and a limited number of uniaxial tests to achieve efficient and reliable strength evaluation. It possesses considerable theoretical innovation and practical engineering value. Full article

This paper develops an analytical treatment of vibro-acoustic wave propagation in a cylindrical waveguide containing two clamped elastic membranes and a central flexible-shell segment. The acoustic field obeys the time-harmonic Helmholtz equation, the shell motion is described by Donnell–Mushtari thin-shell theory under axisymmetric loading, and the membrane response is governed by classical membrane theory and incorporated through a tailored Galerkin scheme. The resulting coupled fluid–structure boundary-value problem is solved by the Mode-Matching Method: the acoustic potentials are expanded in orthogonal radial eigenfunctions within each subregion, and continuity of pressure, normal velocity, and structural displacement are enforced at every interface. The mirror symmetry of the configuration is exploited by an exact decomposition into symmetric and anti-symmetric sub-problems, each of which reduces to a truncated linear algebraic system of dimension $4N+4$ for the unknown modal amplitudes. Acoustic power-balance identities provide a quantitative consistency check on the numerical implementation and diagnose convergence with respect to the truncation order; structural damping is accommodated through complex-modulus substitutions for the shell and the membrane tension without altering the algebraic structure of the system. The numerical results demonstrate that the dual-membrane configuration delivers transmission-loss values exceeding $25\mathrm{dB}$ across the low-frequency band relevant to HVAC and automotive applications, with a representative plateau near $13\mathrm{dB}$ at the reference geometry, through resonance-driven modal coupling between the acoustic field and the compliant interfaces. Parametric studies identify the excitation frequency, the inner-membrane radius, the shell radius, and the chamber length as effective design parameters for tuning the attenuation. The formulation furnishes a unified and computationally efficient analytical tool for predicting and optimising noise attenuation in flexibly coupled cylindrical duct systems. Full article

This study evaluated the safety and effectiveness of HYDRAGEL A2, an injectable medical device containing hyaluronic acid (HA), polynucleotides (PN), and niacinamide, for improving facial skin quality. These ingredients are increasingly recognized for their synergistic effects in aesthetic medicine, with HA and PN providing hydration and skin support, and niacinamide offering anti-inflammatory and antioxidant properties. A prospective, open-label clinical investigation was conducted on 42 female subjects (mean age 45 ± 1 years, Fitzpatrick skin phototypes II-V) to assess skin elasticity, hydration, and mild skin depression correction following cheek area injections. Efficacy was measured using the Global Aesthetic Improvement Scale (GAIS), Antera 3D^® (texture), Cutometer^® (elasticity/firmness), Corneometer^® (hydration), and Dermascan^® (density/thickness) devices at baseline (D0), week 2 (W2/D14), and week 6 (W6/D42). GAIS values showed significant overall facial improvement (p < 0.001) by both investigators and subjects, where 100% of subjects rated their appearance as improved immediately post-injection (D0), with sustained improvements at D42. Objective measurements revealed significant improvements in skin texture (reduced roughness), elasticity, firmness, hydration (p < 0.001), density, and thickness, demonstrating the combined benefits of the HA, PN, and niacinamide blend. Injection site reactions, primarily mild and transient, were reported immediately post-injection. Investigators and subjects reported high satisfaction with the product’s ease of use and aesthetic outcomes. Globally, HYDRAGEL A2, leveraging the established benefits of HA, PN, and niacinamide, was well-tolerated and effectively enhanced facial skin quality, demonstrating significant and sustained improvements in monitored skin parameters. The study concludes that this combination of ingredients, formulated in HYDRAGEL A2, provides a well-tolerated approach associated with improvements in skin quality. Full article

Within the framework of consistent couple-stress theory (CCST), we develop a semi-analytical finite layer method (FLM) to investigate the three-dimensional (3D) coupled electro-mechanical behavior of an exponentially graded (EG) piezoelectric circular hollow microscale cylinder under simply supported boundary conditions. The microscale cylinder is subjected to mechanical loads and electric voltages and is placed under closed-circuit surface conditions on its outer and inner surfaces. Using the principle of stationary potential energy, we first derive a 3D Galerkin weak formulation for this study. We divide the microscale cylinder into n_l layers and select each layer’s elastic displacements and electric potential as the primary variables. We then incorporate a layer-wise generalized displacement model into the weak formulation to develop the semi-analytical FLM. The novelty of our method lies in its ability to accurately determine the electric and elastic field variables induced in the microscale cylinder. This feature has not been explored in previous research. We rigorously validate our method’s accuracy by comparing its solutions for EG piezoelectric circular hollow macroscale cylinders with the corresponding 3D solutions reported in the literature, with the material length-scale parameter set to zero. We also examine the impact of several key factors on the coupled electro-mechanical behavior of the microscale cylinder, including the radius-to-thickness ratio, inhomogeneity index, piezoelectricity, and material length-scale parameter, which appear to be significant. Full article

Wood-based panels are increasingly used in exterior applications; however, comprehensive evaluations of their durability under standardized aging conditions remain limited. This study evaluates the dimensional stability and mechanical performance of three industrial panels designed for exterior use: a three-layer particleboard (PB1) and a single-layer particleboard (PB2), both bonded with phenol–formaldehyde adhesive, and a medium-density fibreboard (MDF), bonded with polymeric methylene diphenyl diisocyanate through accelerated aging. The panels were subjected to six accelerated aging cycles according to the ASTM D1037-12 (2020) standard. Equilibrium moisture content, residual thickness swelling (Residual-TS), bending modulus of rupture (MOR), modulus of elasticity (MOE) in both parallel and perpendicular directions, and internal bond (IB) strength were measured under aged and non-aged conditions. PB2 demonstrated superior dimensional stability (Residual-TS: 0.49%) and strong mechanical retention (MOR: 67%, MOE: 56%–64%, IB: 75%). PB1 showed intermediate dimensional stability and mechanical retention (Residual-TS: 1.58%; MOR: 66%–74%, MOE: 56%–58%, IB: 71%), while MDF exhibited higher sensitivity to aging, with excessive Residual-TS (5.43%) and lower IB strength retention (30%). Specimen orientation did not affect dimensional stability but did influence the bending properties of the particleboard after aging, specifically MOR in PB2 and MOE in PB1. The results demonstrate that PB2 offers superior performance for demanding exterior applications, while PB1 and MDF are suitable for semi-protected uses. All panels were tested in an unfinished state, although surface coatings in actual applications may further enhance the resistance to aging. Full article

To improve the effectiveness of sulfonated polyacrylamide soft microgels (SMGs) in deep profile control, this study investigated a surfactant-assisted regulation strategy based on surfactant uptake and surfactant–microgel association. The uptake behavior of a hydroxysulfobetaine surfactant by SMGs was characterized, and the resulting changes in swelling, frequency-dependent elastic response, electrostatic stabilization, shear resistance, and long-distance transport were evaluated. The surfactant uptake process was well described by pseudo-second-order kinetics and a Langmuir-type saturation model, while FTIR and XPS analyses provided spectroscopic evidence for surfactant association with SMGs, especially at the particle surface. Compared with the SMG system, surfactant addition mildly reduced the swollen median size (D₅₀) at 15 d from 15.72 to 14.90 μm, and the corresponding swelling ratio decreased slightly but remained above 6.45. The S/SMG system also showed a larger magnitude of negative zeta potential, maintaining a value of −38.5 mV after 60 d compared with −32.1 mV for the SMG system, and generally better shear resistance, with particle size retention 0.8–3.8 percentage points higher over 0–7 d of swelling. Serial core-flooding experiments showed improved deep transport behavior. Although the SMG system produced slightly higher injection pressure below 2.4 m, the S/SMG system maintained a slightly higher pressure response beyond this distance. These results demonstrate that surfactant uptake and surface/network association regulate SMG physicochemical properties, thereby improving their transport and deep profile-control performance. Full article

3D concrete printing (3DP) enables automated construction with reduced material waste and enhanced geometric flexibility. However, its structural performance remains sensitive to anisotropy, mix design, and printing parameters, thereby complicating quality control. Self-sensing cementitious materials provide a promising approach by enabling intrinsic strain monitoring during fabrication and service. In this study, a hybrid multi-material printing strategy was developed using a conductive cement-based mix incorporating graphite (G), milled carbon microfibers (MCMF), and chopped carbon microfibers (CCMF), alongside a plain cement-based matrix. Based on percolation analysis, an optimal composition of 2 wt.% G, 0.25 wt.% MCMF, and 0.0625 wt.% CCMF was selected. Reinforced beam specimens were fabricated with the conductive material embedded in either the tensile (bottom) or compressive (top) region, combined with two internal architectures: diagonal infill and solid-base configuration. Four configurations were defined: Pattern 1 (bottom/diagonal), Pattern 2 (bottom/solid-base), Pattern 3 (top/diagonal), and Pattern 4 (top/solid-base). Cyclic three-point bending tests with spatially distributed electrical measurements were conducted to evaluate the electromechanical response in the elastic range. Specimens with the conductive layer located in the tensile region (Patterns 1 and 2) consistently exhibited higher gauge factors than those in the compressive region (Patterns 3 and 4). Pattern 2 exhibited the best sensing performance, with an average gauge factor of 556 and SNR of 31. Across all configurations, SNR decreased with increasing electrode spacing, with reductions of up to 31.0%, demonstrating the effect of current path length on sensing performance. Full article

Background/Objectives: Conventional assessments of lymphatic invasion in the primary tumor may fail to identify lymph node metastasis (LNM) in breast cancer. We evaluated periarterial or perivenous invasion (periA/V), using Elastica–van Gieson (EVG)-stained sections, as a histological marker associated with LNM in invasive breast carcinoma of no special type (IBC-NST), focusing on the impact of invasive tumor size. Methods: We retrospectively analyzed 213 IBC-NST cases. PeriA/V was defined as tumor nests in direct contact with perivascular elastic fibers on EVG-stained sections. Diagnostic performance was compared with that of conventional LI markers (hematoxylin and eosin and D2-40), with stratified analyses by pathological T category (pT1 vs. pT2–4) and pT1 subcategories (pT1a, pT1b, and pT1c). Results: LNM was observed in 87 cases (40.8%). Overall, periA/V demonstrated high sensitivity (97.7%) and negative predictive value (NPV; 93.5%). In pT1 tumors (n = 130), periA/V achieved 100% sensitivity and 100% NPV (27/27), and was consistently present in all node-positive pT1b–c tumors. In multivariate analyses, periA/V remained independently associated with LNM in the pT1 group (odds ratio [OR]: 16.08, p = 0.003) and pT1c subgroup (OR: 14.7, p = 0.010). In pT2–4 tumors, periA/V became frequent regardless of nodal status, indicating reduced discriminatory value. Conclusions: In this exploratory single-center cohort, EVG-based periA/V demonstrated high sensitivity for LNM in pT1 IBC-NSTs, with periA/V negativity consistently observed among node-negative cases. These preliminary findings suggest that periA/V may potentially contribute to LNM risk assessment in early-stage breast cancer. Full article

Deepwater shallow gas sediments and the weakly consolidated overburden are sensitive to depletion-induced effective stress redistribution. Since deepwater shallow gas has only recently begun to be treated as a commercially available natural gas resource, it lacks models to quantify the coupled flow and geomechanical behaviors in such environments. In this study, we propose a semi-analytical model for a shallow gas layer and its overburden sediments, where pore pressure evolution is described by vertical transient diffusion and the stress response is represented by an OCR-dependent (overconsolidation ratio-dependent) in situ stress field with depletion-induced effective stress increments. Pre-yield compressibility is characterized by a stress-dependent nonlinear elastic law, and post-yield deformation is approximated by a Mohr–Coulomb-based yield-controlled plastic correction for engineering purposes. The formulation is used in the base case and during a parametric sensitivity analysis. In the base case, the final settlement is 0.597 m, of which 45.3% is elastic and 54.7% is plastic. The sediments begin to yield after approximately 115 d of production, and the final yielded-thickness fraction reaches 0.268. The sensitivity analysis shows that friction angle, maximum drawdown, gas-layer thickness, and OCR magnitudes predominantly affect the final settlement and yielded-thickness response, while gas-layer permeability has an insignificant effect. Furthermore, the comparison reveals that the depletion timescale governs the stress evolution rate, while depletion pressure drawdown magnitude dictates deviatoric stress evolution and long-term settlement. Considering the engineering condition for the development of typical deepwater shallow sediments, the feasible production parameters should be in the low-to-moderate drawdown and slow depletion range. A practical operating window is approximately 3.6~4.0 MPa maximum drawdown with a depletion timescale of about 340~400 d. This study can provide quantitative insights into the potential commercial production of gas layers in deepwater shallow sediments. Full article

In this study, the structural, thermal, and mechanical properties of nanocomposites obtained by adding zinc oxide (ZnO) nanoparticles (NPs), produced by phyto-mediated synthesis using Dianthus chinensis plant extract, to a PMMA-based photopolymer resin at different ratios (0.05%, 0.10%, 0.15%, 0.20%, and 0.25%, by weight) were evaluated. The prepared composite resins were produced in different test geometries using a DLP (digital light processing)-based 3D printer (Asiga Ultra). Following the structural characterization of ZnO nanoparticles, tensile, compressive, and flexural mechanical tests were performed on the resulting composites, as well as FTIR, TGA, DSC, and DMA analyses. The FTIR results showed that ZnO NPs were physically integrated into the matrix. TGA and DSC analyses revealed that the addition of ZnO NPs, particularly at an addition rate of 0.15%, increased thermal stability. DMA analyses showed an increase in storage modulus and glass transition temperature as the addition rate increased. In mechanical tests, the highest modulus of elasticity and maximum strength values were obtained at additive ratios of 0.10–0.15%. The highest tensile strength (55.31 MPa) and compressive strength (388.53 MPa) were obtained at ZnO contents of 0.10–0.15 wt%, while the maximum flexural strength reached 125.94 MPa at 0.15 wt% ZnO. In addition, the storage modulus increased from 1.469 × 10⁹ Pa for the control resin to 1.872 × 10⁹ Pa for the composite containing 0.15 wt% ZnO, indicating improved stiffness and thermomechanical stability. The stress–strain curves show that improvements in ductility and deformation capacity of the material are achieved at these additive ratios. The findings demonstrate that green-synthesized ZnO nanoparticles are an effective and sustainable additive material for improving the mechanical and thermal performance of DLP-based photopolymer dental resins. Full article

Aiming at the problems of low information management levels and low reuse rate of massive heterogeneous geological data of the Jiangxi Geological Bureau, a Jiangxi geological big data platform based on cloud service and big data technology was designed to realize the integration and sharing of Jiangxi geological big data. Firstly, the architecture of the Jiangxi geological big data platform is designed based on hierarchical thinking, including the infrastructure layer, data layer, platform service layer, application layer and user layer from the bottom up. Secondly, the key technologies for building a Jiangxi big data platform are described, including multi-layer service aggregation, geographic information service bus, geocoding service, Spark big data technology and elastic scaling technology. Finally, the main functions of the Jiangxi geological big data platform are introduced, including a platform portal website, a mobile portal system, a geological big data comprehensive analysis system and a geological 3D modeling system. The operation results of the platform show that the Jiangxi geological big data platform can effectively manage the massive heterogeneous geological data of the Jiangxi Geological Bureau and mine the value of the data. Full article

Investigating the effects of corrosion on the mechanical and fatigue properties of steel wires is critical for the safety assessment of bridge cable structures.This study focuses on high-strength galvanized steel wires used for bridge cables, with a diameter of 7 mm and a strength grade of 1770 MPa. Specimens with varying mass loss rates η were prepared by electrochemical corrosion method, and systematic tensile and fatigue tests were conducted to study the effects of corrosion on the fundamental mechanical properties and fatigue life of the steel wires. The results indicate that the elastic modulus of the steel wires decreases slightly with the increase of η but still meets the requirements of relevant standards. In contrast, the yield strength and tensile strength degrade significantly, while ductility is particularly susceptible to corrosion, showing more severe deterioration. When η is less than 2.75%, the corroded steel wires still maintain favorable fatigue resistance at a nominal stress amplitude of 360 MPa. Once η exceeds this threshold, their fatigue life decreases significantly in a nonlinear manner with increasing η. The fatigue life predicted by a finite element model (FEM) reconstructed based on the 3D scanning geometry of corroded steel wires and combined with the Abaqus/fe-safe module shows good agreement with the experimental results, indicating that this approach can provide a valuable reference for the durability assessment of bridge cables. Full article

This paper investigates the mechanical characteristics of rockbolt under combined tensile–shear loading conditions. By studying the stress and deformation throughout the elastic and plastic stages of rockbolt, a failure model for rockbolt under different tensile–shear combination loadings was established. Key parameters, including the maximum bending moment M_A and total plastic deformation λ, were identified and quantified as they evolve with changes in the displacement angle (combined tensile–shear state). The main novelty lies in formulating the key control parameters governing the elastic–plastic transition and failure process of rockbolts under combined tensile–shear loading and further incorporating them into FLAC^2D to improve the simulation of tensile–shear failure of rockbolts. Numerical simulations of rockbolts under combined tensile–shear loading were performed using FLAC^2D. The influence of a rock mass’ Young’s modulus and uniaxial compressive strength on the mechanical response of the rockbolt was investigated. The results indicate that the ultimate load-carrying capacity of the rockbolt remains essentially constant as the displacement angle increases, while the axial tensile force gradually decreases and the shear force gradually increases. The influence of a rock mass’ Young’s modulus on the stress–strain characteristics of the anchor exhibits a nonlinear positive correlation. When the uniaxial compressive strength of the rock mass is low, the rockbolt is prone to slippage during loading. Full article

Background/Objectives: Carbonic anhydrase I (CAI) is a zinc-dependent metalloenzyme whose inhibitor discovery requires both effective navigation of chemical space and explicit evaluation of coordination-credible binding hypotheses. We aimed to develop an interpretable and reproducible QSAR-to-structure workflow for CAI inhibitor discovery. The workflow links potency prediction with zinc-site plausibility and early developability to support decision-oriented prioritization of new CAI inhibitor candidates. Methods: CAI inhibitors were retrieved from ChEMBL (CHEMBL261) and modeled as $p{K}_i=9-{\mathrm{l}\mathrm{o}\mathrm{g}}_{10}(K_i [\mathrm{n}\mathrm{M}\left]\right)$. AlvaDesc v3.0.8 generated 4224 2D descriptors, which were reduced using train-only preprocessing, variance filtering, correlation pruning, and bagged-tree ranking to a top-100 panel. Five regressors (elastic net, CART, bagging, GB, and XGB) were benchmarked on a held-out test set. Potent ChEMBL seeds (K_i ≤ 10 nM) were used for a 90% 2D similarity PubChem expansion. Predicted hits were then externally validated using independently available PubChem CAI $K_i$ records. Ten novel candidates lacking CAI $K_i$ data were docked to CAI (PDB: 1AZM) via SwissDock AutoDock Vina in neutral and relevant anionic states, with pose selection constrained by a Zn-donor filter (Zn-N/O $\le 2.6$ Å). SwissADME was used to profile physicochemical space, alerts, and absorption/distribution proxies. Results: The bagging model showed the best test generalization ($R^2=0.646$; RMSE = 0.61; MAE = 0.45). PFI and SHAP converged on sulfur/heteroatom connectivity and polar–lipophilic organization as dominant potency drivers. PubChem expansion yielded 25,315 analogs and 233 candidates at predicted $p{K}_i\ge 8.0$; external validation on 145 CAI-measured hits gave $R^2=0.358$ (RMSE = 0.456; MAE = 0.320). Across 20 ligand/protomer docking runs, 12 produced canonical Zn-anchored poses (10 Zn-N; 2 Zn-O). SwissADME indicated consensus logP values from −0.65 to 3.21, 0/10 PAINS alerts, and predominantly favorable drug-likeness (8/10 with zero Lipinski violations), supporting tiered advancement. Conclusions: Integrating interpretable QSAR, external PubChem validation, coordination-aware docking, and SwissADME yields a practical triage framework for CAI inhibitor discovery. The resulting tiered shortlist identifies two Zn-N-anchored N-alkyl sulfamides (CIDs 103935964 and 112684680) and one Zn-O-anchored carboxylate control (CID 122367674) as highest-priority computational hypotheses for staged biochemical evaluation. Full article