Search Results (18,321)

Hydrogen–steel interactions remain a critical concern for the safe deployment of hydrogen–natural gas mixtures in pipeline infrastructures. Thermally grown iron oxides may be a good barrier to hydrogen ingress into the crystalline lattice of pipeline steels, but their actual effectiveness depends strongly on their composition and stability under service conditions. Several experimental approaches have been proposed to investigate the correlation between thermally grown oxides and hydrogen permeation. Among these, electrochemical permeation testing offers a more complex but safer methodology compared to pressurized hydrogen gas tests. However, when the oxide is directly exposed to the charging side (cathodic charging conditions), permeation behaviour often appears comparable to that of bare steel, and rapid oxide degradation occurs. This study introduces an alternative permeation testing configuration that enables direct assessment of thin thermally grown oxides while preserving their structural integrity. By deliberately placing the oxide on the anodic detection side, mechanical removal during hydrogen evolution is suppressed, allowing the intrinsic resistance of the oxide to hydrogen transport to be evaluated. Carbon steel samples were thermally oxidized at 250 °C for controlled exposure times, and the resulting oxide scales were characterized by Raman spectroscopy, revealing variations in hematite and magnetite fractions. Hydrogen permeation was evaluated using a Devanathan–Stachurski cell by positioning the oxidized surface either on the cathodic charging side or on the anodic detection side. Under these conditions, significant variations in apparent steady-state permeation current density were observed as a function of oxidation time and oxide composition. Full article

Lead-bearing dusts from metallurgical processes are hazardous secondary resources due to their complex composition and toxicity. At the same time, their high lead content makes them a promising feedstock for resource recovery. This study proposes an energy-efficient electrosmelting approach based on the partial substitution of sodium carbonate with calcium-rich industrial waste (sugar-industry defecate). Thermodynamic analysis and equilibrium modeling of the Pb–Sb–Fe–Na–Ca–Si–S–Cl–As system were performed in the temperature range of 200–1200 °C using Outotec HSC Chemistry. The results indicate that under equilibrium conditions approximately 90–95% of lead is concentrated in the metallic phase (~56 kg from ~60 kg in the feed), while antimony is co-recovered (~1.9–2.0 kg). The slag is dominated by calcium silicates, primarily Ca₂SiO₄, confirming the important role of CaO in slag formation and impurity fixation. Chlorine is predominantly bound as NaCl and partially as CaCl₂, while sulfur is distributed between Na₂S and Na₂SO₄. A significant portion of arsenic is predicted to be retained in the slag as calcium and sodium arsenates (Ca₃(AsO₄)₂ and Na₃AsO₄), whereas its volatilization is thermodynamically negligible under equilibrium conditions. Preliminary experimental results are generally consistent with the thermodynamic predictions and confirm the feasibility of partially replacing Na₂CO₃ with sugar-industry defecate. The proposed approach contributes to reducing the consumption of conventional fluxes and promotes the utilization of industrial waste within a circular-economy framework. Full article

Phenolic resin is widely used as a binder in high-temperature industries; however, its pyrolysis generally yields isotropic glassy carbon, which strongly influences its high-temperature oxidation behavior. In this work, cupric tartrate was introduced as a catalyst precursor to investigate its effects on the thermal decomposition behavior, microstructural evolution, and oxidation behavior of the phenolic resin pyrolytic carbon. Upon heating, cupric tartrate decomposed at 250–320 °C into nanoscale Cu/Cu₂O composites, which were then converted into metallic Cu nanoparticles through reduction by gaseous products generated during the pyrolysis of phenolic resin. The in situ formed Cu nanoparticles were associated with the growth of tapered carbon nanofibers (CNFs), reaching maximum lengths of 30–50 μm at 700 °C. Based on the observed microstructural features and established literature reports, a dissolution–precipitation pathway is proposed to rationalize the formation of these CNFs. The presence of Cu-catalyzed CNFs correlates with enhanced structural ordering of the pyrolytic carbon, as reflected by reduced I_D/I_G ratios, and with an increased apparent oxidation activation energy in the selected fitting region (from 103.73 to 137.45 kJ/mol). Overall, this work demonstrates a facile strategy in which cupric tartrate serves as an effective catalyst precursor that generates Cu nanoparticles in situ; these nanoparticles then catalyze CNF growth from phenolic resin, enabling the construction of low-dimensional carbon nanostructures. Full article

The Huize Ge-rich Pb-Zn deposit is an important part of the Sichuan–Yunnan–Guizhou carbonate-hosted Pb-Zn metallogenic area and is one of the most representative super-large deposits in the northeastern Yunnan Pb-Zn ore concentration area. The orebodies mainly occur in NE-trending interlayer fault zones. The Pb-Zn mineralization process of this deposit can be divided into the dolomite stage (I), sphalerite-galena stage (II), galena-sphalerite stage (III), and pyrite-calcite stage (IV). Based on a study of the deposit geology, we utilized LA-ICP-MS for in situ microanalysis of trace element compositions and element mapping of sphalerite from different stages to reveal the characteristics of the sphalerite trace element composition and occurrence mechanisms, understand the mineralization process, and constrain the genetic type of the deposit. This research shows that sphalerite color variations result from the multi-factor coupling of multiple trace element contents, element associations, and isomorphic substitutions among elements. Trace elements such as Mn, Fe, Cu, Ga, Ge, Ag, Cd, In, Sn, Sb, and Hg occur in the sphalerite lattice in the form of isomorphic substitutions or nanoscale mineral inclusions, whereas Pb occurs mainly as microscopic mineral inclusions (galena) in sphalerite. From the early to late stages of mineralization (SpI → SpII → SpIII), the mineralization temperature (132–205 °C) and sulfur fugacity (log₁₀ fS₂ = −15.29 to −19.89) both show a gradual decrease. During sphalerite crystallization in different stages, multiple trace elements exhibit coupled multi-element substitutions at the microscale: SpI: Zn²⁺ ↔ (Fe²⁺, Mn²⁺, Cd²⁺), 2Zn²⁺ ↔ 2Ag⁺ + Ge²⁺; SpII: Zn²⁺ ↔ (Fe²⁺, Cd²⁺), 2Zn²⁺ ↔ 2Ag⁺ + Ge²⁺, 3Zn²⁺ ↔ 2Cu²⁺ + Ge²⁺, 3Zn²⁺ ↔ 2(Cu, Ag)²⁺ + Ge²⁺, 2Zn²⁺ ↔ Ga³⁺ + Cu⁺, 2Zn²⁺ ↔ Ga³⁺ + (Cu, Ag)⁺; and SpIII: Zn²⁺ ↔ (Fe²⁺, Mn²⁺), 3Zn²⁺ ↔ 2Cu²⁺ + Ge²⁺, 3Zn²⁺ ↔ 2(Cu, Ag)²⁺ + Ge²⁺). Mn, Fe, and Ge are mainly enriched in SpI; Ga and Ag are mainly enriched in SpII; and Cd is mainly enriched in both SpI and SpII. By comparing the sphalerite trace elements signature of the Huize Ge-rich deposit with those of global typical MVT, SEDEX, VMS, epithermal, and skarn-type Pb-Zn deposits, and considering the deposit’s geological and geochemical characteristics, we suggest that the Huize Pb-Zn deposit is best classified as a medium- to low-temperature, carbonate-hosted Pb-Zn deposit. Full article

The development of efficient and sustainable photothermal catalytic systems is pivotal for modern organic transformations. Herein, we report the rational design and solvothermal synthesis of NH₂-MIL-101(Fe) metal–organic frameworks (NM-101) integrated with carbon nanotubes (CNTs) for the photothermal reduction in nitronaphthalene. The optimized NM-101/75C composites exhibit exceptional catalytic activity and high selectivity under NIR light irradiation, delivering a high yield of 84.4% within 1 h, which significantly outperforms its individual components. Systematic control experiments and detailed spectroscopic investigations reveal a powerful synergistic effect at the MOF-CNT interface, where the CNTs play a dual role in augmenting light harvesting and facilitating charge carrier separation. Furthermore, the high photothermal conversion efficiency of the composite enables rapid reaction kinetics. This work provides a robust and scalable strategy for constructing high-performance photothermal catalysts, offering critical insights into the interfacial engineering of MOF-based materials for industrial chemical manufacturing. Full article

The formation of carbon nanostructures and silicon carbide (SiC) using a single-source precursor offers a simplified route for material synthesis; however, the factors governing the transition between CNT-like structure formation and SiC growth remain unclear. In this study, the growth behavior of carbon-related structures using vinylsilane was systematically investigated by hot-wall chemical vapor deposition (CVD) on various substrates, including Fe bulk substrates and Fe thin films on SiO₂/Si. CNT-like structures were preferentially formed on Fe bulk substrates, whereas Fe thin-film substrates exhibited CNT-like growth at the initial stage followed by increased Si–C-related phase formation with increasing growth temperature and growth time. In contrast, on Fe thin films with limited catalyst amounts, CNT-like growth occurred initially, followed by increased Si–C-related phase formation with increasing growth temperature and growth time. These observations are consistent with a growth transition associated with the balance between Si uptake into the metal and surface SiC formation processes. By controlling catalyst amount, growth temperature, and growth time, the relative formation of CNT-like structures, SiC-rich coatings, and intermediate morphologies could be tuned within a single process. Furthermore, a SiC/CNT-like composite structure was directly formed on a conductive Fe substrate in a one-step CVD process. Electrochemical measurements showed an enhanced current response compared with a bare Fe substrate, indicating preliminary electrochemical activity and suggesting potential applicability as a high-surface-area electrode platform. Full article

Perennially ice-covered lakes in the McMurdo Dry Valleys, Antarctica, are shaped by permanent stratification, extreme oligotrophy, and salinity gradients, yet these features are vulnerable to climate-driven hydrologic change. Because phytoplankton and associated bacteria regulate carbon flow and nutrient cycling, understanding how algal–bacterial consortia respond to disturbance is key to predicting ecosystem change. We used enrichment cultures from Lakes Bonney and Fryxell to test responses to nutrient deprivation and salinity alteration, two perturbations relevant to climate-driven changes in hydrologic connectivity and expansion of open water moats. Autotrophic enrichments lacking added organic carbon were used to enrich algal–bacterial consortia dependent on photosynthetically derived substrates. Community responses were assessed with 16S rRNA amplicon sequencing of size-fractionated samples, allowing comparison of particle-associated and planktonic communities. Short-term nutrient limitation produced only limited shifts in community composition, indicating resistance to transient nutrient stress. However, bacterial communities were strongly structured by size fraction: particle-associated assemblages separated clearly from planktonic communities and were enriched in taxa linked to algal surfaces and polysaccharide-rich microhabitats, including Flavobacteriales, Sphingobacteriales, Rhizobiales, and Rhodobacterales. Salinity perturbation drove stronger restructuring of bacterial communities, with shallow Lake Bonney enrichments showing greater sensitivity than deeper communities. These findings suggest that algae-associated bacterial communities help structure Antarctic algal enrichment cultures and may influence microbial responses to climate-linked disturbance. Full article

This study examines the effect of small ply angle deviations on the structural response of carbon fiber-reinforced polymer laminates representative of structures used in unmanned aerial vehicles (UAVs). A combined experimental and numerical approach was applied, including cantilever bending tests and experimental modal analysis, supported by finite element simulations. Laminates with nominal ply orientations of 0°, 5°, and 10° were manufactured using a manual hand lay-up process to reflect typical production variability. The results show that the numerical model accurately captures the observed trends in both bending deformation and natural frequencies, with discrepancies up to 12.5%. A consistent tendency to slightly overestimate stiffness was observed, leading to lower predicted deflections and higher natural frequencies compared to experimental data. The findings confirm that finite element modeling can reliably detect and predict the structural effects of small fiber misalignment, supporting its use in the assessment and design of lightweight composite structures used in UAV applications. Full article

Battery housings are critical structural and safety components in electric vehicles, fulfilling multiple functions related to mechanical protection, crashworthiness, thermal management, fire resistance, electromagnetic shielding, and integration of battery modules into the vehicle body. While metallic housings, particularly aluminum and steel, remain dominant in industrial applications, increasing attention is being given to composite materials as lightweight alternatives capable of improving energy efficiency and extending driving range. However, the growing use of composites in battery enclosures raises important questions regarding recyclability, end-of-life management, and compatibility with circular economy principles. This review critically examines the current state of the art in composite materials used for electric vehicle battery housings, with particular emphasis on glass- and carbon-fiber-reinforced thermoplastics, thermoset composites, sandwich structures, and hybrid multi-material systems. The paper discusses the functional requirements imposed on battery housings and analyzes how these requirements influence material selection and design strategies. Particular attention is devoted to recycling pathways applicable to composite battery enclosures, including mechanical recycling, thermal treatment, chemical recycling, and reuse-oriented approaches, as well as to the limitations associated with mixed-material assemblies, adhesives, coatings, and integrated functions. The review also addresses circular design strategies for battery housings, including design for disassembly, material traceability, modularity, and the incorporation of recycled polymers and secondary reinforcements into new housing systems. Current research gaps are identified in the integration of structural performance, fire safety, manufacturability, and recyclability within a single design framework. The analysis shows that thermoplastic composites currently offer the most promising route toward circular battery enclosures, while thermoset-based systems still face significant challenges in high-value recycling. The paper concludes by outlining future research directions required for the development of lightweight, safe and recyclable composite battery housings aligned with sustainable mobility and circular economy goals. Full article

This study investigated the rheological, structural, barrier, mechanical, optical, and thermal properties of composite edible films based on citrus pectin and vegetable purées derived from broccoli, cauliflower, pumpkin, carrot, and their blends. Film-forming formulations were characterized in terms of rheological behavior, thickness, microstructure, gas and water vapor permeability, optical and mechanical properties, water contact angle, and thermal stability. The incorporation of vegetable purées significantly modified the properties of the pectin-based matrices. All film-forming solutions exhibited non-Newtonian shear-thinning behavior, with flow behavior index values below unity. The addition of vegetable purées markedly increased viscosity and flow resistance, indicating the formation of more structured systems with stronger intermolecular interactions. Apparent viscosity increased from 0.19 Pa·s in the control sample to 1.41 Pa·s and 1.19 Pa·s in the broccoli (B) and broccoli–cauliflower (B-CF) formulations, respectively, while the consistency coefficient increased from 0.29 to 51.38 Pa·sⁿ. Composite films exhibited lower water contents (0.090–0.114 gH₂O·g_d.m.⁻¹) than the control film (0.179 gH₂O·g_d.m.⁻¹) and were thicker (170–282 μm) than the pure pectin film (125 μm). Barrier analysis revealed a reduction in water vapor permeability from 18.99·10⁻¹⁰ to 10.74–14.69·10⁻¹⁰ g·m⁻¹·s⁻¹·Pa⁻¹ and a decrease in carbon dioxide permeability from 21.95 to 10.47–17.91 GRT. The carrot-containing film exhibited the highest tensile strength (62.17 MPa), whereas the pumpkin–carrot film demonstrated the most favorable combination of barrier and mechanical properties, including the lowest oxygen permeability (6.95 GRT), low water vapor permeability (10.74·10⁻¹⁰ g·m⁻¹·s⁻¹·Pa⁻¹), and high tensile strength (51.02 MPa). Thermogravimetric analysis revealed similar three-stage degradation profiles for all samples, while vegetable incorporation modified moisture release and increased residual mass. The obtained results confirmed the research hypothesis that vegetable-processing by-products can serve as valuable structure-forming components of pectin-based composite films and that interactions between vegetable-derived biopolymers and citrus pectin improve the mechanical, barrier, and functional properties of the resulting materials. Among the tested formulations, the pumpkin–carrot film demonstrated the greatest potential for further development as a biodegradable packaging material. The utilization of vegetable by-products in pectin-based films represents a sustainable approach supporting circular economy principles and the development of environmentally friendly packaging systems. Full article

Progressive stamping is a high-efficiency sheet metal forming method in the automotive and mass production industries, where material characteristics significantly influence process stability, cutting force, tool life, and final part quality. Herein, we report the effects of the chemical composition and mechanical properties of DD11 low-carbon steel on punching force during progressive stamping. Ten DD11 material batches with varying chemical compositions and mechanical properties were subjected to experimental investigation. Material characterization involved spectroscopic chemical analysis, tensile testing in accordance with ISO 6892-1, and hardness measurement. Punching tests were performed with a Zwick BZ2-MMAG100.SH01 universal testing machine that incorporates a punch–die assembly to study force–displacement behavior under controlled conditions. The cutting curves of these materials were analyzed to determine the maximum cutting and fracture loads, which were then statistically correlated with the materials’ chemical and mechanical parameters. The results indicated that tensile strength and yield strength are the strongest statistically significant contributors to the maximum cutting load and the fracture point, and that the correlation coefficients for these measurements were +0.866 and +0.869, respectively. Carbon, chromium, and silicon showed the most positive effect on cutting resistance; whereas, titanium was negatively associated with each of the tested responses among chemical composition measures. But none of the chemical factors were statistically significant. The analysis also showed that material hardness yields the highest predictive performance for cutting force behavior (Pearson correlation coefficients up to 0.935 and a regression coefficient of R² = 0.875). Results of this study show that DD11 cutting behavior at progressive stamping is controlled primarily by strength-dependent mechanical characteristics rather than chemical composition variations. Full article

To ensure the reliability of carbon-fiber-reinforced polymer (CFRPs) structures, robust structural health monitoring (SHM) is required for timely damage diagnosis. Over the decades, Lamb-wave-based techniques have been widely used to inspect composite structures owing to their high sensitivity to internal defects. Damage-sensitive features from nonstationary Lamb-wave signals can be captured in the frequency and time domains using the continuous wavelet transform (CWT). However, extracting localized damage features from these images is highly challenging. Accordingly, this study proposes a multipatch deep feature learning method for damage detection and severity classification in CFRP plates using Lamb-wave CWT images. The images are partitioned into multiple local patches for patch-wise deep feature extraction using a convolutional neural network (CNN). The proposed model is evaluated on CFRP composite plates with three simulated damage severity levels (D1, D2, and D3) produced using mass blocks of different weights. Among the evaluated patch configurations, the proposed physics-inspired patching achieves the highest classification accuracy of 98.2%, outperforming conventional uniform multipatch baselines. For damage detection, the proposed method achieves high classification performance, with precision, recall, and F1-scores of 100% for both healthy and damaged samples, outperforming comparison models, including a custom CNN, VGG19, and ResNet50. For damage severity classification, the proposed model achieves F1-scores of 0.98, 0.97, and 0.98 for D1, D2, and D3, respectively, consistently outperforming the baseline models across various evaluation metrics. Under Gaussian noise, the proposed method maintains a robust classification accuracy of 96.1% at 20 dB signal-to-noise ratio, corresponding to a performance reduction of 1.7% compared with noiseless data, suggesting its reliability for realistic SHM environments. Full article

Background: Collagen-based scaffolds are widely used in regenerative applications, where their structural organization and physicochemical stability are essential for clinical performance. This study aimed to evaluate the influence of hydration on the thermal behavior and microstructural characteristics of a collagen-based matrix (Mucoderm^®, Botiss Biomaterial GmbH, Zossen-Germany). Methods: Differential scanning calorimetry (DSC) was used to investigate thermal transitions in dry and rehydrated samples, while scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS) was employed to assess surface morphology and elemental composition; Results: The dry sample exhibited a broad endothermic transition at 87.8 °C, which shifted to higher temperatures upon rehydration, reaching 103.5 °C and 112.4 °C after 15 and 30 min, respectively. A corresponding increase in enthalpy values was also observed. SEM analysis revealed a heterogeneous surface morphology characterized by alternating compact and less dense regions, while EDS confirmed the predominance of carbon and oxygen with minor elements present in trace amounts; Conclusions: These findings indicate that hydration influences both the thermal response and structural organization of the scaffold, highlighting the role of water–matrix interactions in determining its physicochemical behavior. Full article

With the rapid development of the pharmaceutical industry and animal husbandry, conventional wastewater treatment plants have difficulty effectively degrading the widely occurring ceftiofur sodium (CEF) in aquatic environments. To address this issue, this study successfully loaded Fe/Co-ZIF onto carbon nanofibers (CNF), thereby preparing Fe/Co-ZIF@CNF composites with well-dispersed supported materials and a stable structure. The as-prepared Fe/Co-ZIF@CNF was further applied in a persulfate-based advanced oxidation system (SR-AOPs) for CEF degradation and exhibited good catalytic performance. When the Fe/Co molar ratio was 1.25:1, the Fe/Co-ZIF_1.25 material achieved a CEF degradation efficiency, k_obs value, and TOC removal rate of 94.0%, 0.135 min⁻¹, and 43.8%, respectively. Radical quenching experiments preliminarily indicated that SO₄^•− played a dominant role in the reaction system, while •OH and ¹O₂ also made non-negligible contributions to CEF degradation. This work provides a new strategy for constructing composite catalysts based on carbon nanofiber-supported polymetallic MOFs. Full article

This study compares five Si–Me infiltration coatings, Si:Mo (1:4), Si:Ti (1:1), Si:Zr (1:5), Si:Ta (1:1), and Si:W (1:5), deposited on C/C sonotrodes for ultrasonic atomization of CuSn8. The coatings were evaluated in terms of phase constitution, microstructure, wettability, nanoindentation response, and powder-production performance. XRD showed that the coatings formed distinct multiphase reaction layers, with Si:Ta (1:1) being the most silicide-dominated system, while the other coatings contained carbide or silicide–carbide phases. Metallization strongly improved the surface wettability of C/C, especially for Si:Zr (1:5) and Si:W (1:5). Nanoindentation indicated the most favorable H/E* and H³/E*² descriptors for Si:W (1:5) and Si:Mo (1:4). All coatings enabled high powder yields in single-run atomization tests, while apparent differences in particle-size distribution were observed among the coating conditions. Overall, the results show that coating selection for ultrasonic atomization should combine phase constitution, surface-state descriptors, near-surface mechanical response, layer retention, and process performance. Within the investigated conditions and the limitation of single-run atomization experiments, Si:W (1:5) emerged as the most promising and best-balanced coating candidate, while Si:Ta (1:1) and Si:Mo (1:4) remained relevant alternatives. Full article