Search Results (3,188)

A high-sensitivity fiber-optic hot-wire anemometer based on a liquid-filled leaky-guided fiber Mach–Zehnder interferometer (LGFMZI) with UV-cured polymer/aluminum-microparticle photothermal encapsulation is proposed and experimentally demonstrated. The sensing element consists of a side-polished-fiber-assisted liquid-filled hollow-core fiber structure, in which a refractive-index-selected liquid core is introduced through a microslit to tailor the modal effective refractive-index difference and enlarge the free spectral range. The sensing region is uniformly encapsulated with a UV-cured NOA81 polymer layer containing aluminum microparticles. This encapsulation layer serves as both a photothermal conversion layer under 980 nm LD heating and a mechanical reinforcement layer. Under laser heating, the sensor is subsequently cooled by external airflow, converting wind-velocity variations into monotonic wavelength shifts. Experimental results show that, at an LD current of 80 mA corresponding to an optical power of 16 mW, the single-wavelength-dip sensor achieves a maximum airflow sensitivity of −22.922 nm/(m/s). The device also exhibits a fast transient response, with a rise time of 0.606 s and a fall time of 0.316 s. The proposed liquid-filled LGFMZI combines simple fabrication, photothermal encapsulation, high spectral readability, and stable airflow response, making it suitable for real-time fiber-optic hot-wire anemometry. Full article

Construction on very soft peaty clay remains a major geotechnical challenge due to its high compressibility and low-bearing capacity. The deep mixing method (DMM) is widely adopted for in situ stabilization using cement; however, environmental concerns associated with cement production have driven the search for sustainable alternatives such as geopolymers using low-carbon materials. Existing studies predominantly rely on dried peat, processed precursors such as fly ash or calcined ground rice husk ash (RHA), and high concentrations of alkali activators such as sodium silicate (Na₂SiO₃) and sodium hydroxide (NaOH), which increase both environmental and economic burdens. This study develops a novel waste-based geopolymer incorporating untreated brick kiln-derived RHA, activated solely with low-concentration NaOH, while completely eliminating Na₂SiO₃. The avoidance of precursor pre-treatment and Na₂SiO₃ significantly reduces processing energy, cost, and associated environmental emissions. A systematic investigation was conducted to determine the optimum mixing time for maximizing strength under field-relevant conditions. Mechanical performance was evaluated using unconfined compressive strength tests considering variations in binder content, curing duration (7, 28 days), alkali concentration (6, 3 M), and alkali-to-binder ratio (0.3, 0.5, 0.7). Failure characteristics were examined, and an integrated framework combining cost analysis, life cycle assessment, and grey relation analysis was employed to optimize mix design. The optimized geopolymer achieved 2.2 times higher strength than cement-treated soil, with 25% cost reduction and more than 85% reduction in environmental impact. These findings demonstrate a scalable and sustainable solution for stabilizing highly organic soils, while promoting the valorization of supplementary cementitious materials without energy-intensive preprocessing. Full article

Waste cooking oil (WCO) was investigated as a waste-derived reactive precursor for a cured organic binder in highly mineral-filled composites containing turmeric. Ten formulations selected from a broader experimental screening were prepared from WCO, sulfuric acid, quartz sand, and turmeric added at 1–7% relative to the dry mass of quartz sand. Formulation-specific thermal curing was conducted at 190–210 °C for 12–20 h. Because the binder content, acid-to-binder ratio, turmeric content, curing temperature, and curing time varied simultaneously, the study was designed as an exploratory multifactorial screening rather than as a controlled assessment of individual processing variables. FTIR, ¹H NMR analysis of acetone-soluble constituents, TGA, and SEM-EDS were combined with mechanical screening, water-absorption, contact-angle, and microbiological measurements. Bending and splitting tensile strengths ranged from 1.15 to 2.42 MPa and from 0.30 to 0.52 MPa, respectively. Water absorption ranged from approximately 4.8% to 9.0%, while water contact angles exceeded 90° for all investigated formulations. Selected formulations reduced the surviving fraction by more than 90% for Staphylococcus epidermidis and by approximately 70% for Pseudomonas aeruginosa under the applied suspension-assay conditions. The estimated C₅₀ values of 60.6–83.3 mg mL⁻¹ indicated measurable concentration-dependent responses at relatively high nominal composite concentrations. The available results support curing-associated transformation and consolidation of the WCO-derived binder phase but do not quantify crosslink density or retained organic content. Because no matched turmeric-free composite or surface/eluate pH measurements were available, the biological effects are attributed to the complete composite formulations rather than specifically to turmeric or intact curcumin. The results provide an exploratory basis for the further development of waste-derived, non-load-bearing polymer–mineral composites with functional surface and biological properties. Full article

Background/Objectives: Antibiotics are the recommended first-line therapy for acute uncomplicated lower urinary tract infections (cystitis), but antibiotic resistance and tolerability concerns require antibiotic-sparing strategies. This study evaluated D-mannose as a stand-alone alternative. Methods: This multicenter, randomized, controlled, double-blind study compared D-mannose to fosfomycin in women aged 18–70 with cystitis. Clinical cure (CC) was assessed using the Acute Cystitis Symptom Score (ACSS) up to day 8, with non-inferiority tested at the 15% margin. Post hoc analytical approaches accounted for potential bias due to low sample sizes and missing values. Results: The study randomized 118 patients. At baseline, severe symptoms (ACSS ≥ 12) were more frequent in the D-mannose group compared to fosfomycin (32.8% vs. 22.8%). Efficacy analyses were performed on the per-protocol set (D-mannose: N = 57; fosfomycin: N = 54). Median time to CC was 5.0 days (D-mannose) and 3.0 days (fosfomycin) overall, and 4.0 days vs. 3.0 days in the subgroup of moderate disease severity. The point estimate for the CC rate difference on day 8 (−10.1%) favored fosfomycin but was within the non-inferiority margin. Due to wide confidence intervals, non-inferiority was not statistically confirmed. The post hoc analysis yielded smaller confidence intervals with estimated CC rates of 84.2% (D-mannose) vs. 83.5% (fosfomycin) on day 8 and statistically demonstrated the comparability of both treatments. Recurrence rates were similar (13.2% vs. 13.3%), and there was no statistically significant difference for additional antibiotic use (19.3% vs. 11.1%). Investigators and patients favored D-mannose over fosfomycin for tolerability, and gastrointestinal adverse events were less frequent (9.8% vs. 24.6%). Conclusions: Post hoc analysis indicated that D-mannose treatment is comparable to fosfomycin in uncomplicated cystitis in line with the prespecified non-inferiority criteria. These findings warrant confirmation in an adequately powered trial but suggest that D-mannose is a promising alternative to antibiotics given its favorable risk–benefit ratio. Full article

In this work, a formaldehyde-free bio-based wood adhesive was successfully fabricated using epoxidized soybean oil (ESO) cross-linked with maleic anhydride (MA) and carboxylated lignin sulfonate (CLS). The effect of CLS substitution dosage on the bonding performance was systematically investigated. The results indicated that the dry shear strength and wet shear strength of the adhesive exhibited a typical non-monotonic variation with increasing CLS content, reaching the maximum values of 1.79 MPa and 1.38 MPa, respectively, at a CLS substitution ratio of 40 mol% relative to MA. These mechanical properties fully meet and exceed the requirements of the Chinese national standard for wood adhesives. Orthogonal experiments were further conducted to optimize the hot-pressing process parameters and the optimal conditions were determined as follows: hot-pressing temperature of 130 °C, pressing time of 10 min, glue spread of 280 g/m², and pre-mixing time of 70 min. FTIR, DSC, and TGA characterizations confirmed the complete curing reaction of the adhesive system. The introduced CLS served as both a reactive curing agent and an efficient catalytic component, which effectively reduced the curing temperature, while the incorporation of MA significantly improved the thermal stability of the cured adhesive. This study provides a feasible strategy for the preparation of high-performance, low-cost, and environmentally friendly bio-based wood adhesives. Full article

Coal-based solid wastes, including coal gangue and fly ash, can be extensively utilised in cemented backfill materials. However, the slump, bleeding rate, and mechanical strength of these materials depend nonlinearly on the mixture composition, particle size, solids concentration, and curing conditions, complicating the multi-performance mixture design. This study developed an ensemble-learning framework for the target-specific performance prediction and empirical-uncertainty-aware inverse design of coal-based solid-waste cemented backfill materials. A literature-derived database containing 720 observations and 11 predictors was established. After the target-specific filtering of missing responses, 214 observations were available for the slump, 284 for the bleeding rate, and 711 for the uniaxial compressive strength (UCS). Support vector regression (SVR), Bagging-SVR, AdaBoost-SVR, and Stacking-SVR were evaluated using 20 repeated random 80:20 holdout partitions to assess the within-database predictive performance. Bagging-SVR achieved the lowest mean inner-cross-validation RMSE for all three responses. Its mean test R² values were 0.969, 0.871, and 0.965 for the slump, bleeding rate, and UCS, respectively, with corresponding RMSE values of 2.228 cm, 1.206 percentage points, and 1.575 MPa. SHAP analysis showed that the coal-gangue particle size and solids concentration received the largest model attributions for the slump and bleeding-rate predictions, whereas the cement content and curing time received the largest attributions for the UCS prediction. The selected Bagging-SVR models were subsequently coupled with multi-objective differential evolution incorporating empirical prediction bounds, component mass balance, and target-specific five-nearest-neighbour applicability-domain constraints. The selected compromise candidate had a solids concentration of 79.46% and coal-gangue, fly-ash, and cement dry-solid mass fractions of 63.29%, 24.95%, and 11.76%, respectively. Its predicted slump, bleeding rate, and 28 d UCS were 21.19 cm, 1.85%, and 6.36 MPa, respectively. The nominal empirical upper bound of the bleeding rate was 3.83%, and the lower bound of the UCS was 3.74 MPa, both satisfying their prescribed limits. However, the nominal slump interval of 15.70–26.65 cm was not fully contained within the prescribed range of 18–26 cm. Full article

The construction sector faces a critical need to minimize its carbon footprint, which is currently stimulating the development of geopolymer concrete using recycled coarse aggregates as an eco-friendly material compared with Portland cement. Accurate prediction of the compressive strength of this eco-efficient concrete is complex, however, as a result of the complex, non-linear interactions between many of the mix-design and curing parameters. Although modern scientific literature and engineering practices have increasingly adopted machine learning (ML) for concrete strength prediction, a significant scientific gap remains. Most existing studies rely on “black-box” models that lack sufficient interpretability and frequently overlook the severe risk of data leakage during validation, limiting their practical engineering application. To address this gap, this study proposes a robust, data-leakage-aware framework driven by a rigorous nested GroupKFold cross-validation strategy. By grouping concrete samples by their unique Mix_ID, this approach ensures genuine generalization to entirely unseen mixtures. Within this reliable validation scheme, the CatBoost algorithm is utilized for compressive-strength prediction, with the Dung Beetle Optimizer (DBO) serving as an effective tool for hyperparameter tuning. The evaluation results across multiple random seeds show that the DBO–CatBoost model significantly outperforms the default CatBoost, rigorously tuned baseline models (Support Vector Regression and Random Forest), and a comparative metaheuristic benchmark (PSO–CatBoost). It achieves the most stable distribution of errors and excellent predictive accuracy (Test ${\mathrm{R}}^2=0.9995\pm 0.0002$, RMSE = $0.3828\pm 0.0909$). In addition, the model predictions were demystified using the methods of SHapley Additive exPlanations (SHAP) and partial dependence plots (PDPs). The interpretability analysis revealed strong statistical associations, showing that Curing Time and Coarse Aggregate are the most prominent predictive features and the strongest pairwise interaction between each other; the NaOH molar concentration is the most important second-level influence on optimization of strength. Overall, the framework provides a robust data-driven screening tool that can assist in preliminary mix-design evaluation. By reducing the reliance on extensive empirical “trial and error” approaches, this predictive model supports more efficient material usage and facilitates preliminary optimization of low-carbon concrete formulations. Theoretically, this study advances the fundamental science of geopolymer materials by explicitly quantifying the complex, non-linear interactions between alkaline activators, curing conditions, and recycled aggregates. This provides a robust data-driven theoretical foundation for designing and optimizing next-generation eco-friendly concrete products and structures. Full article

Microwave-assisted recovery provides a potential approach for restoring fracture damage in asphalt mixtures, but previous studies have mainly focused on heating and curing conditions, while the role of the pre-heating fracture state remains less understood. This study investigated microwave-assisted fracture energy recovery from a damage-state regulation perspective by comparing a control asphalt mixture (CAM) with a basalt fiber-reinforced asphalt mixture (BFAM). Semi-circular bending (SCB) tests were combined with an L9 orthogonal design to evaluate three pre-heating conditions, target surface temperatures of 45–85 °C, and curing times of 6–24 h. Rather than directly enhancing binder recovery, basalt fiber reinforcement increased the initial fracture resistance and altered the relative fracture condition reached under a given external load. The recovery index RI ranged from 20.7% to 55.9% for CAM and from 35.2% to 82.3% for BFAM. Main-effects ANOVA showed that the pre-heating damage condition had the largest main-effect contribution within the adopted L9 framework, reaching 82.3% for CAM and 95.2% for BFAM, substantially exceeding those of target surface temperature and curing time. Under a comparable external load of approximately 2.5 kN, CAM reached the 70% P_max condition, whereas BFAM remained at the 40% P_max condition, with corresponding mean RI values of 42.8% and 76.9%. These results support a proposed conceptual damage-state regulation framework within the investigated material and experimental conditions, in which basalt fiber reinforcement preserves a more favorable pre-heating state and thereby greater recovery potential. The findings highlight the importance of improving fracture resistance and applying microwave-assisted treatment before extensive fracture development occurs, while broader validation is required before generalizing the proposed framework to other materials or field conditions. Full article

Pilot-scale validation of controlled CO₂ curing for reinforced concrete members remains limited. This study developed a 2400 L high-temperature CO₂ curing chamber integrating control of temperature, relative humidity (RH), CO₂ concentration, and pressure with real-time monitoring and automated CO₂ regulation. Its applicability was evaluated using commercial concrete bricks and a reinforced concrete slab through mass monitoring, compressive strength testing, phenolphthalein-based carbonation assessment, thermogravimetric analysis (TGA), flexural testing, and carbonation depth measurement. Real-time mass monitoring showed a net mass gain of 50.7 g after 1 h, corresponding to 2.8% of the initial mass. The CO₂-cured bricks achieved a compressive strength of 9.77 MPa, with a calculated CO₂ uptake of 5.72% based on TGA. The CO₂-cured slab exhibited a compressive strength of 41.9 MPa, comparable flexural load capacity to the steam-cured slab, and a higher ductility index of 6.86. Carbonation remained within the concrete cover without reaching the reinforcement. Within the scope of the investigated materials and curing conditions, these results demonstrate the pilot-scale feasibility of controlled CO₂ curing for commercial concrete products and reinforced concrete members and provide a basis for further member-scale validation and process optimization. Full article

This study evaluated the potential use of waste mineral wool recovered from heating pipe insulation as a functional additive in cement concrete. The research aimed to determine the effect of this fibrous recycled material on the mechanical, physical, durability, thermal, and microstructural properties of concrete. One reference mix and three modified mixes were prepared, incorporating waste mineral wool at 12%, 16%, and 20% by cement mass. All mixes were prepared using CEM I 32.5R cement, 0/2 mm basalt aggregate, 2/8 mm granite aggregate, and a superplasticizer. After 28 days of sample curing, compressive strength, splitting tensile strength, density, water absorption, frost resistance, and thermal parameters were determined. Microstructural observations were also performed on concrete fracture surfaces. The results showed that the addition of mineral wool reduced the compressive strength from 84.9 MPa for the reference concrete to 63.8–53.3 MPa for the modified concretes. At the same time, moderate dosing improved the splitting tensile strength, reaching a maximum of 3.93 MPa with a 16% addition. The most favorable thermal effect was achieved with a 12% addition, for which the thermal conductivity coefficient decreased from 1.3461 to 1.1988 W/(m·K). The results indicate that waste mineral wool can be used in concretes with limited structural function; however, its dosage requires optimization due to increased water absorption and decreased compressive strength. Full article

Given that large-scale storage and transportation of liquid hydrogen are key to realizing the hydrogen economy, tank containers have attracted much attention for their flexibility. To minimize evaporation losses, efficient support structures are essential for these liquid hydrogen tank containers. Herein, a carbon fiber-reinforced polymer (CFRP) suspension ring is developed to support the inner vessel of liquid hydrogen tank containers. By using a special resin matrix and optimizing its curing process, the suspension ring capitalizes on a small cross-sectional area and low thermal conductivity, thereby significantly mitigating the cold-bridge heat transferred from the outer vessel to the inner vessel. Experimental results demonstrate that the tensile strength, outgassing rate, and fatigue performance of the suspension ring at both 77 K (liquid nitrogen temperature) and 4 K (liquid helium temperature) can meet the design targets. Notably, its equivalent thermal conductivity was approximately 88% lower than that of a stainless steel structure of the same size. With the integration of this suspension ring into a 40 ft liquid hydrogen tank container, the daily liquid nitrogen evaporation rate was recorded below 0.082%/d. Furthermore, the holding time before the pressure reached 0.14 MPa exceeded 192 h with a 90% liquid hydrogen filling ratio. This work provides key technical support for high thermal insulation, long-endurance liquid hydrogen storage and transportation equipment. Full article

One respondent says antibiotics kill viruses. A second says they do not know. A third says cancer cures are hidden for profit. A standard literacy score counts all three as one deficit. This exploratory study asks whether they behave alike. In a July 2025 Romanian telephone survey (analytic N = 1007), six factual, two worldview-linked and two conspiratorial anti-science (CAS) items were analyzed separately, treating “don’t know” (DK) as a third response. The response patterns did not converge. Factor analysis of substantive answers retained two factors, not one, and the six-item core’s weighted internal consistency among answerers was 0.379. DK responding formed a coherent cross-item pattern, but less uniform than the full-sample alpha of 0.926 implies: it falls to 0.803 once the 135 all-DK respondents are set aside. CAS endorsement converged with generic conspiracist belief and tracked institutional distrust, where factual accuracy did not. Education and internet frequency mainly differentiated DK responding; economic security and democratic satisfaction were associated with lower CAS endorsement. Against Eurobarometer 95.2 (2021), Romanian factual accuracy sits about two items lower than the EU27 average excluding Romania, and CAS endorsement is roughly 1.7 times as high, in both Romanian waves. Uncertainty, error and conspiratorial belief remain conceptually distinct. Full article

The current reuse of blast furnace slag is limited, and the products made from it have low added value and minimal pricing potential. The primary objective of this research is to develop new eco-friendly 3D printing materials using blast furnace slag as the main raw material, simultaneously achieving combined optimization of color appearance and material performance, to increase the reutilization value of slag and address environmental problems caused by slag. Existing studies on slag-based 3D printing materials mainly focus on improving material performance, often neglecting the combined optimization of color and material performance. This study proposes a solution to create colored slag-based 3D printing materials, aiming to break the conventional view of slag waste as simply “black or gray.” This study optimized the particle size distribution of slag-based 3D printing materials using the Andreasen model. The CIELAB color difference formula was applied to reveal how color difference values varied under different mix ratios. Digital image analysis was conducted to evaluate the color characteristics of the specimens and the uniformity of the pigmentation. After 28 days of natural air curing, the color difference ΔE at various measurement points on each colored specimen remained below 3.0, indicating that iron oxide pigments exhibit satisfactory color stability within the slag matrix. To ensure high-quality 3D printing, this study examined the effect of water temperature on the curing time of colored slag-based 3D printing materials. Range analysis results showed that water temperature exerted the most significant influence on setting time (range = 255 s), substantially greater than that of pigment dosage (range = 15 s) and pigment type (range = 5 s). The Herschel–Bulkley constitutive model was used to calculate the flow index of the material. Printing tests confirmed that colored slag 3D printing materials are suitable for extrusion-based 3D printing. The 28-day compressive test results showed that the average fracture load of the three pigmented specimen groups ranged from 23.30 to 24.58 N. Cost analysis further indicated that the comprehensive material cost is approximately 467 RMB/ton, which is lower than that of commercially available colored cement, demonstrating favorable economic competitiveness. The development of colored materials for 3D printing based on blast furnace slag can expand their applications and market potential. It also improves material performance and market acceptance, and its cost advantage over commercial colored cement further enhances its viability for practical applications, promoting high-value recycling and reuse of slag waste. Full article

This study quantitatively investigates the coupled effects of curing temperature and slurry density on the early-age acoustic maturation of ultra-low-density Hollow Glass Microsphere (HGM)-modified oil well cement systems, addressing the critical challenge of determining reliable sonic logging timing under lightweight cementing conditions. Longitudinal wave velocity evolution was systematically characterized across a broad thermo–density domain, revealing a consistent three-stage acoustic trajectory comprising percolation-driven acceleration, transition-controlled consolidation, and acoustic stabilization. The results demonstrate that curing temperature primarily regulates the kinetic rate of acoustic maturation through hydration activation, whereas slurry density modulates the initial structural configuration, HGM-induced acoustic impedance heterogeneity, and development of effective solid connectivity. A derivative-based dual-criterion approach was proposed to define the optimal sonic logging time based on intrinsic acoustic stabilization behavior rather than conventional empirical strength-based thresholds. Furthermore, a thermo–density coupled semi-empirical model incorporating Arrhenius-type thermal activation and density-dependent structural effects was developed, providing reliable prediction of sonic logging timing with clear physical interpretability. The model captures the nonlinear interaction between thermal activation and structural constraints, revealing that acoustic maturation is accelerated under elevated-temperature and higher-density conditions but substantially delayed under low-temperature and ultra-low-density scenarios. This study establishes a physics-informed temperature–density–acoustic coupling framework that links hydration-controlled structural evolution with sonic logging optimization, providing a rational basis for improving cement bond evaluation reliability and operational efficiency under challenging wellbore conditions. Full article

The production of basalt fiber-reinforced polymer (BFRP) core rods for composite cross-arms in power transmission lines currently suffers from high defect rates—including internal porosity, surface cracking, under-curing, and thermal yellowing. Although BFRP exhibits superior mechanical strength, thermal stability, and corrosion resistance compared with conventional glass-fiber-reinforced polymers, industrial-scale manufacturing of BFRP core rods remains immature; critically, the spatial–temporal evolution of thermal curing behavior inside the mold has not been systematically characterized. This knowledge gap relies on costly, time-consuming trial-and-error process tuning. This study develops a validated numerical simulation method grounded in an autocatalytic curing kinetics model, calibrated using differential scanning calorimetry (DSC) experiments, to quantitatively predict the spatiotemporal distribution of temperature and degree of cure during pultrusion-based BFRP core rod fabrication. Four key curing metrics—final surface degree of cure, pre-cure degree, peak core temperature, and through-thickness cure gradient—are identified and rigorously evaluated against critical process parameters (pultrusion speed, pre-cure and cure zone temperatures, and axial temperature gradient) via an L₉ orthogonal experimental design. The model elucidates four distinct defect formation mechanisms, thereby reducing empirical dependence and accelerating the reliable industrial deployment of BFRP core rods in composite cross-arm systems. Full article