Search Results (1,863)

Loess slopes are prone to rapid infiltration, surface erosion, and shallow instability under intense rainfall, highlighting the need for eco-friendly shallow protection methods with enhanced anti-seepage and erosion resistance. To improve the applicability of microbially induced calcite precipitation (MICP) in loess slope protection, this study proposes a combined MICP–sesbania gum (SG) modification method. Permeability tests, surface hardness tests, and indoor artificial rainfall model tests were conducted to systematically evaluate its effects on seepage control and the erosion resistance of loess slopes. The results show that calcium chloride provides a stronger permeability-reducing effect than calcium acetate. Compared with the MICP-only treatment, the combined MICP-SG treatment significantly reduces the permeability coefficient and increases surface hardness. Based on the overall modification performance, a cementation solution concentration of 1.0 mol/L and a curing time of 7 d were selected as suitable treatment parameters. Rainfall model tests further demonstrate that the combined treatment delays erosion failure, reduces infiltration rate and soil loss, and suppresses wetting front migration and internal water content response. These findings indicate that MICP combined with SG can effectively improve the anti-seepage, erosion resistance and surface stability of shallow loess slopes, providing experimental support for eco-friendly shallow slope protection in loess regions. Full article

Self-compacting concrete (SCC) is widely adopted in complex structural engineering due to its excellent flowability and filling capacity. However, in harsh corrosive environments, its complex internal pore structure can easily serve as a preferential pathway for the transport of aggressive media, leading to durability deterioration. This study systematically investigates the effects of chemical attack inhibitor (CAI) on the workability, mechanical properties, sulfate attack resistance, and chloride ion penetration resistance of SCC. The micro-mechanisms governing pore structure evolution are elucidated using low-field nuclear magnetic resonance (LF-NMR) and X-ray computed tomography (X-CT). At a CAI dosage of 2%, the fresh SCC exhibits a slump of 260 mm and slump flow of 720 mm, indicating excellent filling and gap-passing abilities. Meanwhile, the compressive strengths at 3 d, 7 d, and 28 d remain at a high level. After 120 sulfate wet-dry cycles, the strength loss rate is only 8.4%, with an erosion resistance coefficient exceeding 90%. In addition, the resistance to chloride ion penetration is significantly improved, with an electric flux of only 1331 C, which is considerably lower than that of the control group (1637 C). At the optimal dosage of CAI, the concrete exhibits a dense and uniform internal structure devoid of macroscopic defects or cracks, with minimized porosity, thus synergistically enhancing the resistance to sulfate attack and chloride attack. On the contrary, further increasing the CAI dosage markedly intensifies the inhibitory effect of organic components on cement hydration, leading to increased early-age defects and enhanced pore connectivity. Thus, an appropriate amount of CAI can effectively improve the overall performance of SCC, providing a solid experimental basis and theoretical support for its engineering application in harsh corrosive environments. Full article

Background: Pulmonary arterial hypertension (PAH) is a rare and progressive disorder characterized by increased pulmonary vascular resistance and vascular remodeling. Genetic polymorphisms, epigenetic modifications, and ion channel dysregulation are increasingly recognized as key contributors to disease pathogenesis. Anoctamin-1 (ANO1/TMEM16A), a calcium-activated chloride channel, plays a critical role in vascular tone regulation. Objective: This study aimed to investigate the association between ANO1 gene polymorphisms (rs7127129 and rs2509153), promoter methylation status, and serum chloride levels in patients with idiopathic pulmonary arterial hypertension (IPAH), congenital heart disease (CHD), and chronic thromboembolic pulmonary hypertension (CTEPH). Methods: A total of 106 IPAH patients, 40 CHD patients, and 30 CTEPH patients, together with 125 healthy controls, were included. The control group had a comparable age distribution, with a balanced sex ratio, whereas females predominated in all three PH groups. Genotyping was performed using TaqMan-based real-time PCR. Promoter methylation was analyzed using bisulfite conversion followed by quantitative real-time PCR. Serum chloride levels were measured using an ion-selective electrode method. Results: No significant association was observed between rs7127129 and rs2509153 polymorphisms and IPAH or CTEPH (p > 0.05). However, rs7127129 showed a significant association with CHD (p < 0.05). After excluding hypertensive patients, both polymorphisms remained significantly associated with CHD. Serum chloride levels differed significantly among groups (p < 0.001), with higher levels observed particularly in the CTEPH and CHD groups compared to controls, while IPAH patients exhibited intermediate but still elevated levels relative to controls. In contrast, promoter methylation levels were significantly lower in all patient groups compared to controls. An inverse relationship between chloride levels and methylation status was observed. Conclusions: ANO1 polymorphisms are not major determinants of IPAH or CTEPH but may contribute to CHD susceptibility. Increased serum chloride levels, together with decreased promoter methylation, suggest a potential mechanistic link between ion channel dysregulation and epigenetic alterations in pulmonary hypertension. Further large-scale and functional studies are warranted. Full article

Calcium leaching increases the hydraulic concrete material’s porosity and the diffusion coefficient, thereby jeopardizing engineering safety. Fly ash and silica fume are commonly used mineral admixtures in hydraulic concrete, and their effects on the material’s leaching characteristics, especially its microstructural and transport properties, require further investigation. In this study, calcium leaching tests were conducted on cement paste (CP), silica fume–cement paste (SF), and fly ash–cement paste (FA) using a 6 mol/L ammonium chloride solution to accelerate the leaching process. Subsequently, a series of quantitative and qualitative analyses was performed on the deteriorated specimens, including phenolphthalein indicator spraying, X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and scanning electron microscopy (SEM). Additionally, the diffusion coefficients of the material at different locations were calculated and analyzed. The results show that partially replacing cement with silica fume or fly ash increases the initial porosity, gel pore content, and initial diffusion coefficients. After 28 days of leaching, compared to the initial values, the porosity increases in the 0–4 mm layer from the leached surface were 83.6% for CP, 11.0% for SF, and 39.0% for FA. The diffusion coefficients increased by factors of 14.3 (CP), 6.1 (SF), and 13.6 (FA), indicating enhanced resistance to leaching. The primary reason for this is that the reactive silica in the admixtures undergoes a pozzolanic reaction with the calcium hydroxide generated by cement hydration, producing additional calcium silicate hydrate (C-S-H) gel, which reduces the capillary pores that would otherwise result from calcium hydroxide decomposition. Full article

This study presents a closed-form analytical solution for large-deformation pressure-induced stress and displacement fields in thick-walled, functionally graded (FG) hyperelastic polyvinyl chloride (PVC) cylinders subjected to internal pressure. The formulation inherently satisfies incompressibility—an aspect not guaranteed by standard finite element methods (FEMs)—and provides explicit expressions for all stress and deformation components. Using a Mooney–Rivlin model with an exponential–logarithmic gradation law, the study examines bi-layer and tri-layer configurations under varying property-changing scenarios. The governing equations are reduced to a single nonlinear scalar relation for the radial mapping constant, ensuring computational efficiency. Analytical predictions demonstrate excellent agreement with FEM results (errors < 1%) and recover homogeneous limits, and demonstrate that continuous gradation significantly reduces stress concentrations compared to discrete layering. The proposed model offers an efficient tool for designing pressure-resistant FG hyperelastic components for engineering applications such as pipes, hoses, biomedical devices, and protective casings. Full article

To investigate the corrosion resistance and deterioration mechanism of cast-in situ concrete incorporating iron ore tailings aggregate (IOT), specimens with IOT replacement ratios of 0%, 30%, and 50% were exposed to distilled water, endogenous Cl⁻-SO₄²⁻ corrosion, exogenous Mg²⁺-SO₄²⁻ corrosion, and endogenous-exogenous coupled corrosion. The evolution of mass, size, compressive strength, and flexural strength was evaluated, while Nuclear Magnetic Resonance (NMR), Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS), X-ray Diffraction (XRD), and Thermogravimetric Analysis/Derivative Thermogravimetry (TG/DTG) were used to characterize pore structure and phase transformation. Results show that distilled water causes limited variation, whereas exogenous and coupled corrosion accelerate product accumulation, size expansion, pore coarsening, and strength degradation. Under exogenous Mg²⁺-SO₄²⁻ corrosion, the peak compressive strengths of specimens with 0%, 30%, and 50% IOT reach 43.30 MPa, 45.60 MPa, and 46.93 MPa, respectively, with the 50% IOT specimen showing an 8.38% increase compared with the specimen without IOT. TG/DTG results show that the Ca(OH)₂ related mass loss decreases from 5.42% under distilled water immersion to 4.37% under exogenous Mg²⁺-SO₄²⁻ corrosion, confirming calcium consumption during sulfate–magnesium attack. Microstructural characterization reveals that sulfate reaction, chloride binding, and Mg²⁺-induced decalcification jointly promote the formation of gypsum, ettringite, Friedel’s salt, magnesium silicate hydrate (M-S-H), and magnesium-associated corrosion products. Overall, 30% IOT provides better pore refinement and mechanical stability under endogenous and exogenous corrosion, whereas 50% IOT improves residual skeleton support under coupled corrosion. These findings provide guidance for durability design and sustainable utilization of IOT aggregate in cast-in situ concrete. Full article

Steel bridge deck pavements in coastal hot–humid regions are often exposed to the combined effects of moisture, salt, and temperature, which can accelerate material deterioration and shorten service life. To clarify the durability behavior of typical paving materials under such conditions, a comparative study was conducted on three asphalt mixtures used for steel bridge deck pavements: epoxy asphalt mixture (EA-10), dense-graded asphalt mixture (AC-13), and stone mastic asphalt mixture (SMA-10). The mixtures were subjected to hygrothermal salt-water cycling using a mixed chloride-sulfate solution, and their durability was evaluated through air void content, indirect tensile strength, and four-point bending fatigue tests. The results showed varying degrees of deterioration. The air void content of AC-13 increased by about 41.4% after 28 d at 60 °C, suggesting greater susceptibility to internal void damage under severe conditioning. The indirect tensile strength also decreased with wet–dry cycling; at 60 °C and 28 d, the strength retention of EA-10 remained 76.9%, higher than those of AC-13 and SMA-10. After conditioning at 60 °C, the fitted slope of fatigue life for SMA-10 reached −0.0052, compared with −0.0044 for AC-13 and 0.0027 for EA-10, indicating that SMA-10 was the most sensitive to hygrothermal salt attack, whereas EA-10 was the least affected. Overall, the resistance to hygrothermal salt-water damage followed the order EA-10 > AC-13 > SMA-10. The findings help clarify the durability behavior of steel bridge deck paving materials in coastal environments and provide support for durability-oriented material selection. Full article

In this study, the fluidity and the flexural and compressive strengths of self-compacting concrete with iron tailings powder are measured. The influence of basalt fibers and steel fibers on the mechanical strengths and the attenuation of performance after NaCl erosion has been investigated. The mass ratio of iron tailings powder ranges from 0% to 20%. The volume ratio of fibers increases from 0% to 3.5%. The influence of hybrid basalt-steel fibers is considered. The results indicate that the mechanical properties vary in the form of cubic functions with the mass ratio of iron tailings powder and the volume ratio of fibers. Specimens with 15% iron tailings powder exhibit the highest mechanical performance. At this dosage, the flexural and compressive strengths are increased by rates of 12.2% and 8.5%, respectively. Specimens reinforced with 2% basalt fibers or 2.5% steel fibers individually exhibit the highest mechanical performance, the lowest chloride ion impermeability, and the best resistance to chloride salt erosion. The hybrid combination of 0.5% basalt fibers and 3% steel fibers provides the optimal fiber dosage. An amount of 2% basalt fibers or 2% steel fibers increase the flexural strengths by rates of up to 48.9% and 84.8%, respectively, while the corresponding compressive strengths are increased by up to 12.5% and 20.9%. The chloride ion migration coefficient of specimens are decreased by up to 37.86%, 30%, and 42.14% with 2.5% basalt fibers, 2% steel fibers, and a hybrid combination of 1.5% basalt fibers and 1% steel fibers, respectively. Specimens with 15% iron tailings powder exhibit the highest amount of dense hydration products and the least amount of cracks. Full article

This study investigates the effect of sintering temperature on the hot-corrosion behavior of Ti-6Al-4V alloy in a molten salt environment. Samples were sintered at 800 °C, 900 °C, 1000 °C and 1100 °C, then exposed to the Na₂SO₄—25%NaCl for 300 h at 650 °C. The corrosion kinetics were evaluated by measuring the mass change in the specimens, and the results were correlated with their corresponding corrosion rates. The results show that the sintering temperature drives corrosion kinetics by influencing the sample density and grain size. The sample sintered at 900 °C shows a low corrosion rate due to its refined microstructure. This refined microstructure provides a high grain boundary density, which serves as a diffusion path and enables the formation of a dense, protective Al₂O₃–TiO₂ layer, as confirmed by XPS. In contrast, the sample sintered at 800 °C exhibits high porosity, resulting in an initial weight loss due to molten-salt penetration and evaporation of volatile metal chlorides. The samples sintered at 1000 °C and 1100 °C exhibit coarsened grains, leading to a thicker, brittle oxide layer and severe delamination, which in turn result in high corrosion rates. The results show that optimizing the sintering temperature to around 900 °C would enhance hot-corrosion resistance in salt-contaminated environments. Full article

Next-generation wastewater treatment and recycling rely on membrane-based processes, but they face a trade-off among permeability, selectivity, and fouling resistance. In the present study, thin-film nanocomposite (TFN) membranes were fabricated by incorporating a ternary TiO₂-SiO₂-biochar nanofiller into a polysulfone (PSf) support using nonsolvent-induced phase separation, after which m-phenylenediamine and trimesoyl chloride were used via interfacial polymerization to produce a selective polyamide layer. The membrane compositions were M1 (22 wt.% PSf), M2 (22 wt.% PSf/0.5 wt.% TiO₂/0.5 wt.% SiO₂/0.5 wt.% biochar), and M3 (polyamide-coated M2). FTIR, XRD, SEM, contact-angle, porosity, and mechanical analyses supported successful membrane formation and changes in morphology, wettability, and structural strength after nanofiller incorporation and TFC coating. The addition of a nanofiller increased the hydrophilicity of the membranes by decreasing the water contact angle from 98.6 ± 0.8° for pristine PSf to 35.6 ± 1.5° for the nanocomposite membrane. Consequently, the pure-water permeability increased from 21 to 37 L m⁻² h⁻¹ bar⁻¹. After polyamide layer formation, the optimized TFN membrane maintained a contact angle of 55.4 ± 3.8° and achieved a high Congo red rejection of 98% with permeate flux of 7–9 L m⁻² h⁻¹ bar⁻¹. The membrane also showed good antifouling performance, with flux recovery ratios exceeding 90%. For heavy-metal-containing solutions, the optimized membrane showed apparent removal efficiencies of 78–98% for multivalent heavy metals (Pb²⁺, Hg²⁺, Cd²⁺, Mn²⁺, Zn²⁺, Cu²⁺, Ni²⁺, Fe³⁺, As³⁺, and Cr⁶⁺). Static adsorption tests showed the order M2 > M3 > M1, confirming that exposed TiO₂-SiO₂-biochar sites contribute to pollutant uptake, while the superior filtration performance of M3 is attributed to the combined effect of the polyamide selective layer and adsorption-assisted interactions. Overall, the TiO₂-SiO₂-biochar-based TFN membrane provides a promising platform for dye removal and preliminary heavy-metal attenuation from contaminated water. Full article

Seawater zinc–air batteries (SZABs) stand out as promising candidates for marine and offshore energy supply. However, their practical implementation is greatly restricted by tardy oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics at the air cathode, severe chloride ion-induced catalyst corrosion, and structural deterioration of traditional binder-containing electrodes in seawater media. Herein, we design and fabricate a binder-free integrated electrode consisting of carbon-supported iron phthalocyanine- modified star-like cobalt sulfide arrays directly grown on nickel foam. The optimal catalyst (0.3FePc-C/CoS) integrates the respective advantages of Fe single atoms and cobalt sulfide, exhibiting excellent ORR and OER activity, delivering a prominent half-wave potential of 0.89 V versus RHE, and exhibiting a low OER overpotential of 160 mV at 50 mA cm⁻² and robust stability in seawater. As a self-supported air cathode, the 0.3FePc-C/CoS-based battery attains a favorable open-circuit voltage reaching 1.48 V, prominent peak power density (126.4 mW cm⁻²), small charge–discharge potential polarization (0.52 V), excellent energy efficiency (68.8%) and extraordinary long-term cycling durability (>360 h). This work not only discloses a feasible synergistic modulation strategy for constructing high-performance bifunctional electrocatalysts but also provides a valuable reference for developing corrosion-resistant integrated air electrodes toward practical marine energy storage applications. Full article

The utilization of construction and demolition waste (CDW) as a supplementary cementitious material (SCM) represents a promising strategy for reducing cement consumption, minimizing environmental impacts, and promoting sustainable waste valorization. In this study, hybrid recycled powder was produced from mixed CDW obtained from a Portuguese recycling facility and processed through mechanical grinding to achieve particle size characteristics comparable to Portland cement. The ground powder was subsequently thermally activated at 600 °C and evaluated as a partial replacement for Portland cement in concrete. Concrete mixtures were prepared with recycled powder replacement contents of 5%, 15%, 25%, and 35%. The physical, mechanical, and durability properties of the concrete were investigated, including density, water absorption, compressive strength, carbonation and chloride penetration resistance. The results indicate that thermally activated recycled powder can be successfully incorporated as a partial cement replacement while maintaining satisfactory mechanical and durability performance. These findings demonstrate that thermally activated hybrid recycled powder derived from mixed CDW has significant potential as a sustainable SCM, contributing to reduced cement consumption and supporting the development of low-carbon concrete. Full article

To elucidate the corrosion behavior of Ti-based metallic glass composites in chloride-containing environments, this study investigates the corrosion resistance of an in situ dendritic Ti₄₈Zr₂₀Nb₁₂Cu₅Be₁₅ metallic glass composite across varying NaCl concentrations and temperatures. The microstructure, surface film composition, and corrosion characteristics were characterized using XRD, SEM, TEM, EDS, XPS, and electrochemical measurements. Results indicate that the alloy consists of a β-Ti(Zr, Nb) dendritic phase embedded in an amorphous matrix. Both increasing NaCl concentration and rising temperature lead to an increase in corrosion current density and a reduction in the capacitive loop radius, signaling a decline in corrosion resistance. The degradation is primarily characterized by localized corrosion and the selective dissolution of the amorphous matrix, which leaves the dendritic phase increasingly prominent. Following polarization, a multi-component oxide film, dominated by TiO₂, ZrO₂, and Nb₂O₅, develops as a protective layer on the alloy surface. However, higher Cl⁻ concentrations and temperatures destabilize this passive film, accelerating matrix dissolution and compromising the material’s overall protective performance. Full article

To investigate the mechanism by which a combination of desert sand (DS) and recycled coarse aggregate (RA) affects the sustainability of recycled concrete, multiple mix proportions with varying replacement ratios were designed in this study. Macroscopic performance tests and microscopic analyses were performed using nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and X-ray diffraction (XRD), and the results were combined with grey relational analysis to reveal the intrinsic relationships between pore parameters and macroscopic properties. Additionally, technical and economic evaluations were conducted. The results indicate that incorporating either type of aggregate individually has a nonlinear effect on the compressive strength and impermeability of concrete. The optimal compressive strength is achieved when both aggregates are used at 20% replacement, whereas the best impermeability occurs at 10% replacement for each. The proportions of transitional pores and capillary pores, along with T₂ relaxation parameters, serve as key microstructural indicators for controlling performance. Economically, the use of both aggregates together significantly reduces material costs—reaching a cost savings rate of 3.51% with a recycled aggregate replacement level of 30%. Further substitution of 30% desert sand for river sand under the same replacement ratio can reduce costs by an additional 1.56%. This mix proportion achieves optimal synergy among mechanical performance, cost control, and low-carbon benefits. The findings provide theoretical guidance and practical support for mix design, durability enhancement, and the promotion of such green, low-cost concrete in engineering applications. Full article

The corrosion behavior of copper and a Cu-Fe-P alloy in 3.5% NaCl solution was studied in this paper. This study focused on the influence of microalloying in the Cu-Fe-P alloy containing 0.003 wt% Fe and 0.014 wt% P on corrosion resistance in chloride media. Additionally, the effect of 2-mercapto-1-methylimidazole as an inhibitor was evaluated using electrochemical techniques, including potentiodynamic polarization, cyclic voltammetry, and electrochemical impedance spectroscopy. According to the potentiodynamic polarization results, 2-mercapto-1-methylimidazole can be classified as a mixed-type inhibitor. The inhibition efficiency also increases with increasing concentration. The results indicate that the Cu-Fe-P alloy has improved corrosion resistance compared to copper, and a higher inhibition efficiency of 2-mercapto-1-methylimidazole was observed for the Cu alloy. Full article