Search Results (604)

Reinforcement congestion in reinforced concrete (RC) beam–column joints creates constructability difficulties and may compromise seismic performance due to inadequate consolidation and confinement. Although fiber-reinforced concrete (FRC) has been widely investigated as an alternative to dense transverse reinforcement, current seismic codes (e.g., ACI 318-19, TBEC-2018) do not provide explicit provisions to quantify the interaction between steel fiber dosage and joint shear demand. This study examines the feasibility of partial stirrup replacement through a hybrid confinement strategy that preserves minimum transverse reinforcement for bar stability while using steel fibers to compensate for joint shear demand. Two large-scale exterior beam–column assemblies were tested under quasi-static reversed cyclic loading: a code-compliant reference specimen and a hybrid specimen incorporating minimum stirrups with 0.5% hooked-end steel fibers. The hybrid specimen exhibited improved stiffness retention and energy dissipation without brittle joint shear failure. A validated nonlinear finite element model (VecTor2) was used to conduct a parametric investigation covering beam reinforcement ratios of 1.3–1.5% and fiber volume fractions of 0.5–1.2%. Results demonstrate a consistent non-linear interaction between beam-induced joint shear demand and fiber contribution. This interaction is formulated through a demand-based exponential relationship that links required steel fiber dosage to joint shear demand while preserving minimum transverse reinforcement for longitudinal bar stability. The proposed model provides a design-compatible framework for hybrid fiber-stirrup confinement in seismic design practice. Full article

To address the critical limitation of insufficient high-temperature structural stability in traditional formaldehyde-resorcinol aerogels for thermal protection applications, this study designed and fabricated a high-silica fiber felt-reinforced phenolic aerogel composite capable of in situ ceramization. The thermal insulation performance, structural stability, mechanical properties, and oxidation resistance mechanism after heat treatment at 1000 °C for 600 s were systematically investigated. Results demonstrated tunable density (0.398–0.629 g·cm⁻³), low room-temperature thermal conductivity (0.0414 W·m⁻¹·K⁻¹), and a stabilized back temperature of 408.6 °C during butane torch flame testing. After high-temperature treatment, the composite series exhibited a minimum volume shrinkage of 13.9% and a maximum mass retention of 77.6%. Specifically, the compressive strength and specific strength of the HS/C-75 sample reached 4.39 and 1.96 times those of the HS/C-0 sample, respectively. Further analysis revealed that the synergistic effect between the skeletal support of high-silica fibers and the in situ-formed ceramic phase effectively suppressed thermal shrinkage and improved oxidation resistance, achieving an optimized balance between thermal insulation and mechanical integrity. This work provides a theoretical foundation and viable technical pathway for developing advanced thermal protection materials with enhanced stability and reliability. Full article

The balanced performance of fiber-reinforced flexible (FRF) pipes is essential for maintaining dimensional stability and structural integrity in pipelines. However, current theoretical approaches face challenges in simultaneously incorporating end effects, geometric nonlinearity, and material nonlinearity, resulting in a persistent reliance on engineering experience when determining balanced fiber winding angles. This work proposes a semi-analytical method for evaluating the balanced performance of thick-walled FRF pipes, based on the strain energy density function, with governing equations established by integrating finite deformation theory and the principle of minimum potential energy. A displacement trial function is adopted to approximate the actual displacement field, with its coefficients determined iteratively using the Newton–Raphson method. An eight-coefficient displacement trial function demonstrates effectiveness in characterizing the pipe’s deformation characteristics under the maximum working internal pressure, capturing key deformation features such as radial inward expansion with outward restraint gradient, nonlinear axial deformation, and axial end warping. The proposed method is validated against both experimental results and finite element simulations, and an analysis of the fiber winding angle’s influence on balanced performance is conducted, thereby establishing a theoretical basis for the design of self-balanced thick-walled FRF pipes. Full article

Antimicrobial resistance (AMR) remains a serious public health concern, and methicillin-resistant Staphylococcus aureus (MRSA) continues to limit treatment options. This laboratory-based comparative study evaluated antibiotic resistance patterns and nanoparticle (NP) susceptibility among 110 S. aureus isolates recovered from human skin and soft tissue infections (n = 80) and camel milk (n = 30). Proteomic identification utilizing matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) was carried out for all isolates under study. Phenotypic differentiation between MRSA and methicillin-sensitive S. aureus (MSSA) was performed via the cefoxitin disk diffusion method, and antimicrobial susceptibility testing was carried out using the disk diffusion method as stated in international guidelines. Multidrug resistance (MDR) was defined by established criteria. The antibacterial activity of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) was detected by broth microdilution to determine minimum inhibitory concentration values (MIC₅₀ and MIC₉₀). The ability to develop reduced susceptibility was evaluated through ten serial sub-inhibitory passages followed by stability testing without using nanoparticles. MRSA prevalence was 52.5% among human isolates and 70% among camel milk isolates. Overall, 56.4% of isolates met MDR criteria, with a significantly higher MDR rate among MRSA compared with MSSA. Both human and camel isolates showed similar resistance patterns. AgNPs exhibited strong antibacterial activity, with MIC₅₀ and MIC₉₀ values of 0.0078 mg/mL and 0.0156 mg/mL, respectively; nevertheless, AuNPs demonstrated higher MIC values. Response to NPs was similar between isolates, independent of methicillin resistance or MDR. Serial sub-inhibitory exposure resulted in increased MIC values in all tested isolates, and stable resistance persisted in 50% of cases. These results indicate ongoing MRSA circulation in human and animal settings and reinforce the need for careful and controlled use of NP-based antimicrobials. Full article

Traditionally, Lasiocephalus ovatus Schltdl. (Asteraceae) has been used as an aromatic medicinal plant, particularly in the treatment of kidney-related ailments. However, scientific evidence validating its chemical composition and bioactivity remains limited. According to our literature search, there are no previous studies on the in vitro antibacterial, antioxidant, or anti-inflammatory activities of the essential oil from the aerial parts of Lasiocephalus ovatus; therefore, this study provides the first experimental evidence of these biological activities for this species. An essential oil (EO) was steam-distilled from the aerial parts of L. ovatus, grown at 4410 m above sea level in the paramos of Chimborazo Province (Ecuador), and subsequently analyzed. The distillation yield was 0.21% (w/w) based on dry plant material. Gas chromatography was employed for qualitative (GC-MS) and quantitative (GC-FID) analyses, using two different capillary columns, coated with 5% phenyl methyl polysiloxane (non-polar) and polyethylene glycol (polar) stationary phases. Dual stationary phases were required to provide complementary selectivity, which reinforced the identification and quantification of compounds. The major components of the EO were silphinene (3.4–3.5%), δ-selinene (3.6–3.1%), β-cyclogermacrene (18.7–18.1%), kessane (4.5–4.2%), spathulenol (13.3–13.3%), viridiflorol (3.1–3.0%) and neophytadiene (4.8–4.4%), values referred to the non-polar and polar phase respectively. The enantioselective analysis revealed that (1S,5S)-(−)-α-pinene, (1S,5S)-(+)-β-pinene and (R)-(−)-α-phellandrene were enantiomerically pure, whereas germacrene D was present as a scalemic mixture. The essential oil of L. ovatus exhibited a minimum inhibitory concentration (MIC) of 250 µg/mL against Staphylococcus aureus and 500 µg/mL against Escherichia coli. Its antibacterial activity is likely associated with the presence of bioactive sesquiterpenes such as silphinene, δ-selinene, and spathulenol, which are known for their membrane-disruptive properties. Regarding its antioxidant potential, the observed moderate radical scavenging activity (SC₅₀ = of 375.7 µg/mL) can be attributed to its complex mixture, particularly to oxygenated terpenoids like viridiflorol and spathulenol, which are recognized for their radical-neutralizing capacity. In the anti-inflammatory assay, the EO’s moderate potency (IC₅₀ = 165.29 ± 4.75 μg/mL) is also consistent with the anti-inflammatory profile reported for several of its major constituents, including spathulenol and viridiflorol. While significantly lower than that of aspirin (28.85 ± 7.66 μg/mL), this bioactivity is considerable within the context of a plant extract. Overall, the antibacterial, antioxidant, and anti-inflammatory effects are consistent with the EO’s terpene-rich composition, particularly oxygenated sesquiterpenes, while the enantiomeric distribution of chiral monoterpenes may further modulate bioactivity; consequently, future studies should include enantioselective quantification, broader antioxidant assays (e.g., ABTS, FRAP, ORAC, CUPRAC), cytotoxicity at active concentrations, and mechanistic and in vivo validation. Full article

Bridges are critical components of transportation networks, and fire accidents can significantly impair their structural integrity, leading to safety risks and major economic losses. This study presents a comprehensive inspection, materials testing, repair, and field load testing program for a full-scale concrete box girder bridge (Delta Bridge, Alexandria, Egypt) following a fire exposure on two spans. A total of 28 concrete core samples were extracted and tested, revealing average compressive strengths of 48.50 MPa (slab), 53.90 MPa (web), and 45.88 MPa (columns), representing moderate reductions of approximately 8.5%, 7.9%, and 10.8%, respectively, relative to the original in situ concrete strength recorded during construction, and 29.2%, 43.7%, and 30.0% increases over the minimum acceptance limits specified by Egyptian code of practice (ECP 203). Tensile strength tests on reinforcement bars indicated an average yield strength reduction coefficient of 0.87, corresponding to an estimated peak exposure temperature of 600 °C, yet still satisfying Egyptian code requirements (≥500 MPa). Field static load tests using 40-ton tri-axle trucks demonstrated maximum midspan deflections of 6.7 mm in fire-exposed spans and full recovery (>94%) upon unloading, confirming that the residual stiffness and load-carrying capacity were within acceptable limits. Based on these results, a targeted repair program was executed, including concrete cover replacement with shotcrete; steel derusting; surface coating; and bearing replacement, followed by a verification load test that confirmed the effectiveness of the rehabilitation. This case study demonstrates a robust framework for post-fire condition assessment, residual capacity evaluation, and repair validation of concrete box girder bridges. The methodology and findings provide valuable guidance for engineers and transportation authorities in mitigating fire-induced risks and ensuring the safe reopening of critical bridge infrastructure. Full article

To clarify the shear lag effect and flexural performance of glass fiber-reinforced polymer (GFRP) composite truss web girder bridges and verify the feasibility of substituting steel truss webs with GFRP members, a refined finite element (FE) model was established via ABAQUS. Transverse and longitudinal stress distributions in concrete slabs were systematically analyzed under mid-span concentrated, full-span distributed, and two-point symmetric loads, with a parallel performance comparison against steel truss web girder bridges. The transverse shear lag effect exhibited distinct interlayer differences, with the top slab effective width ratio 15–20% lower than that of the bottom slab; stress peaks at truss-slab joints stemmed from concentrated shear transfer, while bottom slab stress troughs were induced by boundary constraints. Longitudinally, the effective width ratio averaged 0.65 at beam ends, dropped to the minimum at loading points, and recovered to over 0.98 in non-loaded zones. Performance comparisons showed that under the applied load patterns, the GFRP system exhibited a flexural performance similar to that of the steel system, with mid-span deflection differences of 0.29–0.30 mm and normal stress deviations below 0.1 MPa. This study quantifies the multi-case shear-lag response characteristics, verifies that GFRP truss webs can achieve flexural behavior comparable to steel webs under the investigated conditions, and provides theoretical support for the refined design and engineering applications of this novel bridge structure. Full article

This study aims to evaluate the feasibility of replacing the minimum shear reinforcement in high-strength self-compacting lightweight concrete (HSLC) beams with hooked-end steel fibers at a volume fraction of 0.75 vol.% and to quantitatively assess the contribution of steel fibers to the shear capacity of the beams. Six HSLC beam specimens were tested to determine load-bearing behavior and failure modes under different reinforcement schemes, including beams without steel fibers or stirrups, beams reinforced with either steel fibers or stirrups, and beams incorporating both steel fibers and stirrups. The experimental results indicate that replacing the minimum shear reinforcement with 0.75 vol.% hooked-end steel fibers increased the flexural capacity, ultimate deflection, and energy absorption capacity by 2.5%, 7.8%, and 16.1%, respectively, thereby confirming the feasibility of using hooked-end steel fibers as a substitute for minimum shear reinforcement. The fiber shear capacity, calculated from experimental data, was compared with various prediction equations. Models containing the fiber factor demonstrated better agreement with test results, showing a minimum difference of 10.1%. Full article

Climate change exerts a pronounced influence on streamflow regimes by altering precipitation characteristics and potential evapotranspiration, thereby affecting global water availability and hydrological functioning. This study investigates the hydrological behavior of the Upper Indus River Basin (UIRB), a strategically important transboundary mountainous watershed, under a range of future climate scenarios. An integrated modeling approach combining process-based simulation and data-driven techniques is employed to generate new insights relevant to the advancement of the Sustainable Development Goals (SDGs). The Soil and Water Assessment Tool (SWAT) and a Long Short-Term Memory (LSTM) neural network were calibrated and validated using daily streamflow observations spanning 1995–2014. During the calibration phase, SWAT yielded an R² of 0.71, a Nash–Sutcliffe Efficiency (NSE) of 0.59, and a PBIAS of 20.3%. In comparison, the LSTM model demonstrated improved predictive performance, achieving an R² of 0.72, an NSE of 0.71, and a PBIAS of −1.85%. Future discharge simulations were derived from bias-corrected climate projections obtained from 11 General Circulation Models under SSP245 and SSP585 scenarios for four future time slices (2015–2035, 2036–2055, 2056–2075, and 2076–2099), using 1995–2014 as the reference period. Under the high-emission SSP585 pathway, basin-wide precipitation is projected to increase by 14.7% by the late century, accompanied by substantial rises in maximum and minimum temperatures of 17.9% and 36.25%, respectively. SWAT simulations indicate streamflow increases of 7.1–9.9% under SSP245 and 10.1–11.7% under SSP585, whereas the LSTM model projects more pronounced increases of 17–25.6%. The outcomes of this research contribute significantly to multiple SDGs, with quantified impacts on SDG 6 (Clean Water and Sanitation, 35%), SDG 13 (Climate Action, 30%), SDG 2 (Zero Hunger, 15%), SDG 15 (Life on Land, 12%), and SDGs 8 and 9 (Economic Growth and Infrastructure, 8%). The proposed integrated modeling framework supports enhanced water security through optimized resource planning, reinforces climate resilience by strengthening adaptive capacity, promotes agricultural sustainability in irrigation-reliant regions, safeguards fragile mountain ecosystems under accelerating glacier retreat, informs the development of climate-resilient agricultural sustainability in irrigation-reliant regions, and informs the development of climate-resilient infrastructure. Collectively, these findings highlight the urgent necessity for adaptive water management policies to address climate-induced hydrological uncertainty in stressed transboundary river basins and offer a transferable framework for achieving water-related SDGs in climate-sensitive regions worldwide. Full article

Voltage security assessment is increasingly challenged by stochastic demand growth and localized stress patterns that are not well represented by deterministic, single-snapshot analyses. This paper proposes a fully steady-state probabilistic stress-testing framework based on Monte Carlo simulation and Newton–Raphson AC power flow, jointly evaluating the minimum bus voltage magnitude $V_{min}$ (voltage-floor adequacy) and the scenario maximum Fast Voltage Stability Index $FVS{I}_{max}$ (worst-case line stress). Stress is injected selectively on screened weak buses by sampling a random stress footprint and intensity across three progressive levels (L1–L3), while preserving the local power factor. The approach is demonstrated on IEEE 14-, 30-, and 118-bus benchmark systems using $N=2000$ realizations per level, with 100% convergence across all cases. Across all systems, results show a consistent, monotone degradation of the voltage floor and a systematic increase in violation risk as stress intensifies. For the IEEE 14 system, the voltage-risk profile escalates rapidly, with $\mathbb{P}(V_{min}<0.90)$ rising from 0.16 (L1) to 0.54 (L3), while the worst-case FVSI tail strengthens markedly (p95 increasing from 0.1455 to 0.2081), indicating a growing likelihood of severe voltage-stress events. In contrast, the IEEE 30 and IEEE 118 systems exhibit milder shifts in central voltage levels but maintain substantial exposure relative to the 0.95 pu planning threshold, with $\mathbb{P}(V_{min}<0.95)$ reaching 0.79 and 0.74 at L3, respectively. Beyond risk magnitudes, the framework reveals a nontrivial structural phenomenon in worst-case line stress: as system size increases, stochastic stress outcomes become increasingly concentrated into a small number of dominant transmission corridors. Recurrence analysis at the highest stress level shows fragmented criticality in IEEE 14 (Top-3 lines sharing criticality), near-total dominance by a single corridor in IEEE 30 (>92% of cases), and complete dominance collapse in IEEE 118 (one corridor governing 100% of $FVS{I}_{max}$ events). These results demonstrate that probabilistic stress-testing can simultaneously quantify voltage-risk escalation and expose hidden structural bottlenecks that remain invisible under deterministic screening, providing a scalable diagnostic tool for planning-stage monitoring and reinforcement prioritization. Full article

The building sector has a significant environmental impact throughout the life cycle of a building. Reducing the environmental load of the building sector is essential for creating a sustainable society. Many current reports focus on carbon emission, while other environmental impacts remain insufficiently evaluated. Furthermore, buildings serve different functions depending on the region, and the types and quantities of primary materials used vary accordingly. Under these circumstances, little research has focused specifically on Japan. This study conducted a life cycle assessment (LCA) covering the life cycle of material inputs (structural and finishing materials) for 95 buildings in Japan. In addition to greenhouse gas emissions, multi-criteria analysis, including characterization and integration (characterization such as acidification, ozone layer destruction, and photochemical ozone; damage assessment; and integration using LIME2 and LIME3), was conducted. Based on analyses of numerous buildings, the objectives were to clarify trends in environmental impact emissions by building use, conduct an environmental impact analysis that could serve as a future benchmark, and discuss for reducing these environmental impacts. First, the analysis of trends such as maximum, median, and minimum values across six building types revealed that the environmental impact per square meter tended to be lower for production and logistics facilities and higher for offices, government buildings, schools, hospitals, hotels, and condominiums across many indicators. However, significant variations were observed between individual buildings within each category. These results can serve as a benchmark for the environmental impact of future buildings in Japan. Next, GHG emissions and integration (LIME2, LIME3) were quantitatively identified for materials with high emissions, and the factors were considered. Furthermore, processes with high environmental impacts associated with the material were analyzed and identified. Ready-mixed concrete, reinforcing bars, and steel frames showed high values across quantitative indicators, whereas wood and other materials varied by indicator. Finally, based on these findings, perspectives for reducing the environmental impact of key materials are proposed for each stakeholder group. Full article

Sheep wool is a keratin-based natural fiber increasingly explored as a low-impact reinforcement and multifunctional modifier in composites, enabling valorization of coarse or waste wool streams. This systematic review consolidates evidence on raw or minimally processed wool-reinforced composites across polymer matrices and mineral binders. Following a registered protocol and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020, Scopus and Web of Science were searched for English-language journal articles (2015–2025), yielding 44 included studies after screening. Evidence mapping shows polymers dominate (33/44; thermosets 19/44), while mineral binders account for 11/44. Wool is mainly used as short fibers (27/44), with woven (9/44) and nonwoven/felt (8/44) architectures appearing in laminates and insulation products. Because heterogeneity limits pooled meta-analysis, outcomes are synthesized using matched-control comparisons where available (27/44) and interpreted with a TRiC appraisal (Transparency, Reproducibility, and Credibility). Mechanical effects are highly conditional: gains in impact/energy absorption and occasional tensile/flexural stress improvements coexist with frequent losses linked to dispersion, wetting/impregnation and void sensitivity. Functional trends are similarly system-dependent, with promising but uneven evidence for acoustic performance, variable thermal conductivity shifts, and formulation-driven fire behavior. Moisture uptake and durability emerge as principal translation bottlenecks, motivating minimum reporting and design practices to improve comparability and application readiness. Full article

Carbon fiber-reinforced polymer (CFRP) composites modified with alumina (Al₂O₃) and silicon carbide (SiC) nanoparticles were developed to produce hybrid nanocomposites with improved mechanical and thermal characteristics. This study investigates the hot drilling behavior of unidirectional CFRP and hybrid nanocomposites by examining the effects of spindle speed, feed rate, drill diameter, and drill geometry (step, core, and twist). Response Surface Methodology (RSM) and Analysis of Variance (ANOVA) were used to identify the most influential parameters governing drilling-induced damage. ANOVA results revealed that drill geometry was the most dominant factor, contributing more than 89% to delamination, burr formation, and surface roughness, followed by drill diameter with over 7% contribution. For temperature rise, drill geometry accounted for more than 50% of the total variation, while drill diameter contributed over 17%. Among the tools evaluated, the step drill produced the minimum drilling-induced damage, followed by the twist drill. In terms of material performance, the Al₂O₃-reinforced hybrid nanocomposite exhibited superior drilling behavior compared to the SiC-reinforced and neat CFRP laminates. Overall, the results demonstrate that drilling-induced damage under hot drilling conditions can be effectively minimized through appropriate selection of tool geometry and process parameters, confirming the suitability of hot drilling for machining aerospace-grade CFRP hybrid nanocomposites. Full article

This paper presents a hybrid framework for multi-stock trading that combines the decision-making ability of Deep Q-Networks (DQN) with the allocation precision of portfolio optimization models. Realistic markets are noisy and non-stationary, and complex action spaces can hinder reinforcement learning (RL) performance. The DQN generates buy/sell signals based on market conditions. The framework passes buy-listed assets to an optimizer, which computes portfolio weights. Five allocation strategies are examined: naïve 1/N, Markowitz Mean–Variance, Global Minimum Variance, Risk Parity, and Sharpe Ratio Maximization. Empirical evaluations on emerging-market exchange-traded funds (ETFs), as well as additional tests on U.S. equities, show that even the baseline DQN outperforms traditional technical indicators. Furthermore, integrating any of the optimization approaches with DQN yields measurable improvements in return-risk performance metrics. Among the hybrid frameworks, DQN combined with Sharpe Ratio Maximization delivers the most consistent gains. The findings highlight the value of decomposing stock selection from capital allocation and demonstrate the effectiveness of the proposed DQN-optimization framework on our testbed. Full article

Objective: Based on our previous findings, we designed new molecules by extending functionalized pyrazole derivatives containing iodine atoms, which are linked via an amino bond to halogen-substituted phenyl groups. In addition, these newly developed pyrazole compounds exhibit anti-tumor, antibacterial, and anti-biofilm activities. Methods: Three new series of pyrazole compounds were designed. Fifteen novel pyrazole derivatives, distributed across three series (4a–d, 5a–d, and 6a–g), were synthesized and structurally characterized by ¹H-NMR, ¹³C-NMR, FTIR, UV-Vis spectroscopy, and elemental analysis. Results: Among them, compound 4c, which exhibited notable anti-tumor activity, crystallized in a monoclinic system and was further analyzed via single-crystal X-ray diffraction. All synthesized compounds were evaluated in vitro on NCTC normal fibroblast cells and HEp-2 tumor epithelial cells. Compound 4c demonstrated significant anti-tumor activity while displaying no cytotoxic effects on normal cells. The antibacterial and anti-biofilm activities of the compounds were also assessed against four bacterial strains. Compounds 5a and 5c exhibited the highest antibacterial activity against Staphylococcus aureus ATCC 25923, both with a minimum inhibitory concentration (MIC) of 0.023 μg/mL. Additionally, compounds 4a, 5a, 6a, 6e, and 6f showed the strongest anti-biofilm effects, each presenting a minimum biofilm inhibition concentration (MBIC) of 0.023 μg/mL. ADME and ADMET in silico predictions indicated that all compounds exhibit generally favorable, drug-like physicochemical properties. Conclusions: The study reinforces the applicability of these compounds as promising anticancer, antibacterial, and anti-biofilm drugs. Full article