Search Results (31,658)

Hydrogen-enriched fuel injection in staged gas-turbine combustors is commonly achieved through jet-in-crossflow (JICF) configurations, where flame stabilization is governed by a local balance between flow-induced strain/mixing and chemical reaction rates. This work investigates turbulent reacting JICF relevant to staged combustion conditions using high-fidelity simulations with adaptive mesh refinement (AMR) and differential-diffusion effects together with Lagrangian particle statistics. Chemistry model uncertainties are incorporated by using a projection method that maps uncertainty estimates from detailed mechanisms into the model used in this work. Results show that the macroscopic flame topology remains in a stable two-branch regime (lee-stabilized and lifted) and is primarily controlled by the jet momentum–flux ratio J. Visualization of the normalized scalar dissipation rate reveals that the flame front resides on the low-dissipation side of intense mixing layers, occupying an intermediate region between over-strained and under-mixed regions. While hydrogen content does not significantly change the global stabilization mode for the cases studied, uncertainty analysis reveals composition-dependent differences that are not apparent in the mean behavior alone. In particular, visualization in Eulerian (χ, T) state-space analysis and particle statistics conditioned on the stoichiometric surface demonstrate that higher-hydrogen cases observe a lower scalar dissipation rate and exhibit substantially reduced variability in OH production under kinetic-parameter perturbations, whereas lower-hydrogen blends experience higher dissipation and amplified chemical sensitivity. These findings highlight that, even in globally similar JICF regimes, the hydrogen content can modify the local response of the flame to kinetic-parameter uncertainty, motivating uncertainty-aware interpretation and design for hydrogen-fueled staging systems. Full article

High-grade non-oriented silicon steel is a critical material for new energy vehicles and energy-efficient appliances due to its superior magnetic properties. However, these properties are significantly degraded by non-metallic inclusions, particularly Ti(C,N). This study employs integrated thermodynamic and kinetic calculations to systematically analyze the formation and growth mechanisms of Ti(C,N) inclusions in high-grade non-oriented silicon steel, trace the sources of [Ti], and propose targeted theoretical control strategies. Results indicate that Ti(C,N) inclusions do not precipitate above the liquidus temperature (1779 K). During solidification, microsegregation enriches Ti, C, and N; however, only TiN precipitates in the final stage as its ion product exceeds the solubility limit, whereas TiC remains undersaturated—findings valid within the present composition window and modeling framework. Inclusion size is governed by cooling rate and initial Ti/N content, where higher cooling rates yield finer inclusions and lower Ti/N content suppresses precipitation. Titanium originates from primary sources (raw materials and alloys) and secondary sources (decomposition or reduction of TiO₂ in slag/refractories). Therefore, mitigating [Ti] requires strictly limiting primary input and suppressing secondary formation through optimized process control, such as reducing BOF slag carryover, lowering refining temperature, and controlling [Al] content. Full article

The increasing deployment of dense offshore wind turbine monopile foundations pose significant challenges for accurately simulating tidal-flow modification and energy transport at the array scale. Balancing physical realism with computational efficiency remains a key challenge in hydrodynamic modelling of offshore wind farms. In this study, an established drag-based source-term approach is implemented through a dedicated module developed within the TELEMAC-3D framework to represent the momentum-blocking effects of offshore wind-farm arrays. A representative dense 8 × 10 wind turbine monopile array configuration is constructed in a typical tidal channel to systematically examine array-induced tidal-flow responses. The results indicate that the drag-based source-term approach preserves the regional-scale tidal flow structure while effectively capturing array-induced local velocity adjustments and pronounced downstream wake attenuation and recovery. Detailed analyses further reveal distinct spatial and temporal characteristics of the velocity response, including the decay and recovery of velocity deviations downstream of the array. In addition, the monopile array induces a clear modulation of flow kinetic energy, characterized by enhanced energy dissipation and a finite array-scale redistribution of kinetic energy. These findings demonstrate that this approach efficiently simulates the array-scale hydrodynamic and energetic impacts of large offshore wind farms and contribute to a better understanding of array-induced tidal flow modification and energy redistribution. Full article

A ternary CdS–MoS₂–rGO photocathode was developed to enhance visible light-driven hydrogen evolution through interfacial heterostructure engineering. The composite was fabricated via a solution-based deposition method followed by thermal conversion, resulting in crystalline CdS and MoS₂ phases that were uniformly integrated within a conductive reduced graphene oxide (rGO) framework. Structural and surface analyses (XRD and XPS) confirmed the coexistence of Cd²⁺, Mo⁴⁺, and S²⁻ chemical states without detectable secondary phases. Photoelectrochemical measurements revealed that the ternary architecture significantly improves charge separation efficiency and interfacial charge-transfer kinetics compared to binary and single-component films. The CdS–MoS₂–rGO photocathode exhibited the highest photocurrent density, reduced charge-transfer resistance, and favorable Tafel slope under visible-light irradiation (0.25 sun, neutral electrolyte). Gas chromatography measurements verified that these electrochemical enhancements translate into increased hydrogen production rates, following the trend: CdS–MoS₂–rGO > CdS–rGO > MoS₂–rGO >> rGO. Applied bias photon-to-current efficiency (ABPE) analysis further confirmed improved photon utilization efficiency in the ternary system. The enhanced performance is attributed to synergistic integration of CdS (light harvesting), rGO (rapid electron transport), and MoS₂ (catalytic edge sites), which suppresses recombination and accelerates proton reduction kinetics. These findings demonstrate that rational multi-component heterostructure design is an effective strategy for improving hydrogen evolution rate under mild operating conditions. Full article

In this study, chicken bone biochar (CBC) was prepared from waste chicken bones via oxygen-limited pyrolysis. A magnetic component (Fe₃O₄) was introduced, and the composite was embedded in a sodium alginate (SA) gel network, successfully constructing magnetic chicken bone biochar/sodium alginate composite gel beads (M-CBC/SA). The experimental results showed that under the conditions of pH = 4.5, 25 °C, and an adsorbent dosage of 0.5 g/L, the removal efficiency of M-CBC/SA toward 50 mg/L U(VI) reached 91.67%, corresponding to an adsorption capacity of 91.67 mg/g. The adsorption process followed the pseudo-second-order kinetic model and the Langmuir isotherm model, with a theoretical maximum adsorption capacity of 322.58 mg/g, indicating that the adsorption was dominated by monolayer chemisorption. The material exhibited excellent magnetic separability and good anti-interference ability against coexisting ions such as K⁺, Na⁺, Cl⁻, and SO₄²⁻, and its adsorption behavior was only weakly affected by ionic strength. Characterization by XRD, FTIR, XPS, SEM-EDS and other techniques revealed that the immobilization mechanism of U(VI) involved the synergistic effects of dissolution–precipitation (the formation of a new autunite phase), surface complexation (involving hydroxyl and phosphate groups), ion exchange (exchange with Ca²⁺), and electrostatic attraction. Using waste chicken bones as the raw material, this composite achieves both efficient uranium immobilization and convenient magnetic separation, fully embodying the environmental concept of “treating waste with waste”, and shows promising application prospects in the treatment of uranium-containing wastewater. Full article

Hydrogen (H₂) was produced from recycled aluminum microparticles (180–250, 300–425, and 425–500 μm) via alkaline hydrolysis using a 1.0 M NaOH solution to enhance oxide layer removal and aluminum dissolution. Maximum hydrogen flow rates of approximately 13, 15, and 19 mL·min⁻¹ were obtained, confirming that smaller particle sizes promote faster reaction rates due to increased specific surface area. The hydrogen evolution exhibited two-stage kinetic behavior: an initial stage characterized by rapid aluminum dissolution and increasing H₂ production, followed by a gradual decline associated with the formation of a passivating Al(OH)₃ layer. Despite the higher reaction rates observed for smaller particles, the maximum cumulative hydrogen production was obtained for the intermediate particle size (363 µm, 132 mL), compared to 106 mL and 102 mL for 215 µm and 463 µm, respectively, indicating a trade-off between surface area and passivation effects. Kinetic analysis based on the shrinking core model showed excellent agreement (R² = 99.94–99.97%), with rate constants of 0.137, 0.064, and 0.050 min⁻¹. The relationship k ∝ d⁻ⁿ (n ≈ 1.4) suggests a mixed kinetic regime involving both surface reaction and diffusion through the Al(OH)₃ layer. These findings indicate that hydrogen generation can be modulated by particle size; however, the relatively low flow rates and yields limit its immediate practical applicability. Full article

Vascularization remains a central challenge in thick tissue engineering. Building on our prior demonstration that carbonate buffer concentration governs multi-channel collagen gel (MCCG) architecture and perfusion culture performance, this study aimed to establish non-contact, orthogonal control of pore size and density in riboflavin-sensitized Type I collagen hydrogels via UV irradiation intensity and preparation temperature. UV intensity was modulated by varying the source-to-sample distance (25–52 mm); preparation temperature was set at 5, 25, or 40 °C; gelation kinetics were quantified using a vial-tilt assay. Pore area fraction ranged from 0.9% to 8.6% and Young’s modulus from 16 to 49 kPa depending on UV dose. Higher preparation temperatures accelerated gelation and produced smaller, more densely distributed pores, consistent with kinetically arrested phase separation. NIH/3T3 fibroblasts cultured on intermediate- and low-intensity UV scaffolds achieved >80% confluency by Day 7, with three-dimensional tissue-like organization and directionally aligned cellular bundles within large pores; cell metabolic activity, assessed by CCK-8 assay, remained consistently high throughout the culture period. These results demonstrate that UV irradiation intensity and preparation temperature are independently tunable, non-contact parameters for reproducible fabrication of collagen scaffolds with tunable vascular-like pore networks, complementing and extending the chemical (buffer concentration) design space of MCCG-based perfusion culture systems. Full article

Vacuum drying is a promising alternative to conventional dehydration for heat-sensitive vegetables, although process temperature can significantly affect both drying behavior and product quality. In this study, vacuum drying of cauliflower florets (Brassica oleracea) was evaluated at 40, 50, 60, 70, and 80 °C under 10 kPa, using freeze-drying as a reference. Desorption isotherms were determined at 50 and 70 °C and fitted to common models, where the GAB model provided excellent fits (R² = 0.9999 and 0.9997, respectively). The drying kinetics were successfully described by four thin-layer models, with the Midilli–Kucuk and Weibull models performing best overall. Color was significantly affected, with total color differences (ΔE) ranging from 15.9 to 20.6 and higher browning indices at elevated temperatures. Bioactive compounds (total phenols, flavonoids, and glucosinolates) and antioxidant potential (by DPPH and ORAC assays) were quantified to assess changes in functional quality across treatments. Bioactive compounds showed the highest values at the highest temperatures (60–80 °C). The DPPH assay remained stable between 50 and 80 °C, but ORAC assay decreased with increasing temperature, suggesting that vacuum drying at 60–70 °C offers the best balance between overall bioactive retention and functionality for producing cauliflower powder. Full article

Conductive core–shell superabsorbent polymers (SAPs) are emerging as multifunctional additives for cementitious materials, combining moisture management with electrical functionality. In cement-based systems, a swellable polymeric core enables internal curing and crack-sealing through controlled water uptake and release, while a conductive shell introduces ionic and/or electronic charge transport, addressing key limitations of conventional non-conductive SAPs. This dual functionality provides a pathway toward smart cementitious composites with enhanced durability, self-sensing capability, and moisture-responsive behavior. This review focuses on the physical chemistry mechanisms governing conductive core–shell SAPs in cementitious environments, with emphasis on swelling thermodynamics, water transport kinetics, interfacial phenomena, and charge transport mechanisms. The roles of osmotic pressure, elastic network constraints, ionic effects, and pore solution chemistry are critically discussed, together with their impact on conductivity, hydration processes, microstructure development, and long-term performance. The relative contributions of ionic and electronic conduction are examined in relation to hydration state, shell morphology, and percolation of conductive networks. In addition, the relevance of core–shell SAP architectures to sustainable packaging is briefly discussed as a secondary application, illustrating how similar physicochemical principles—such as moisture buffering and functional coatings—apply beyond construction materials. Finally, key knowledge gaps are identified, including long-term stability in highly alkaline environments, trade-offs between swelling capacity and conductivity, environmental impacts of conductive phases, and the need for integrated experimental and modeling approaches. Addressing these challenges is essential for the rational design and practical implementation of conductive core–shell SAPs in next-generation cementitious materials. Full article

Fully compressible two-phase flow configurations present many challenges for numerical modelling, requiring the development of Real Fluid Models (RFMs) able to simulate flows in subcritical, transcritical and supercritical regimes. Such an RFM has been recently developed at IFPEN based on physical properties lookup tables, mainly for binary and ternary chemical systems. This paper proposes an Artificial Neural Network (ANN) approach to overcome the limitations of lookup tables of thermodynamic properties and to apply RFM to multi-species combustion. A methodology for generating an optimized data set by combining a vapor–liquid equilibrium (VLE) thermodynamic solver and the in situ adaptive tabulation (ISAT) method is developed. It aims to improve the neural network training process for two-phase combustion simulations where many species are present. This ANN methodology has been implemented in the CONVERGE CFD solver and validated using a mixing layer (LOX/GH₂) benchmark from the literature relevant to rocket conditions, and an academic gaseous (H₂/O₂) case relevant to hydrogen combustion. The results show that this ANN approach makes H₂ combustion simulation possible when coupled to the RFM framework and using a 10-species kinetic mechanism. Full article

In this paper, we study an inverse problem for the nonstationary Stokes system in a bounded domain $\mathrm{\Omega }$ with a nonlinear integral overdetermination condition, describing the kinetic energy $E\left(t\right)$ of the fluid. We construct two classes of solutions: weak and very weak. In the case where the kinetic energy E belongs to $W_2^1(0,T)$, we construct weak solutions. If E belongs only to $L_2(0,T)$, we construct very weak solutions. Full article

Licania tomentosa leaf extract was used to synthesize zinc oxide nanoparticles (ZnO NPs) which were systematically analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Visible (UV-Vis) and Fourier transform infrared (FT-IR) spectroscopies and energy-dispersion X-ray spectroscopy (EDS) methods. Based on XRD scans, the green NPs have an average crystallite size of 15.9 nm as estimated using the Scherrer equation and have a roughly spherical shape with an average diameter of 25.15 ± 1.2 nm as calculated from SEM data. As estimated from the Tauc plot based on UV-Vis absorption spectra, ZnO NPs have a small band gap of 3.0 eV. The biosynthesized ZnO NPs were effectively utilized for the photodegradation of methylene blue (MB) and crystal violet (CV) dyes under UV illumination with resulting MB and CV degradation efficiencies of ~94% and ~81% after 60 min and 70 min, with pH = 12 and pH = 10, respectively. Different experimental parameters such as NPs quantity, experimental pH, light intensity and initial concentration of dyes were varied to test the performance of the catalyst. Furthermore, efficient recycling of the catalyst was demonstrated. We also undertook antimicrobial studies of the green ZnO NPs. The ZnO NPs demonstrated broad-spectrum antimicrobial efficacy against Escherichia coli ATCC 35218, Enterococcus faecalis ATCC 29737, Klebsiella pneumoniae ATCC 700603, Pseudomonas aeruginosa ATCC 27853, P. aeruginosa B3, Staphylococcus aureus ATCC 29213, and S. aureus SA01, with the minimum inhibitory concentration (MIC) and the inhibitory concentrations associated with 50% effect (IC50) values ranging from 250 to 2000 µg/mL and 7.74 to 283.14 µg/mL, respectively. The nanoparticles also significantly inhibited biofilm formation by E. faecalis ATCC 29737, P. aeruginosa ATCC 27856, and S. aureus SA03. The antimicrobial efficiency of the ZnO NPs against Escherichia coli ATCC 25922 and Staphylococcus aureus SA03 isolates was also assessed using the disk diffusion assays. Taken together, our results reveal that the biosynthesized ZnO NPs are promising multifunctional materials with potential applications in antimicrobial treatments, biofilm control, and photocatalytic remediation. Full article

Improving the dissolution and solubility of poorly water-soluble drugs remains a major challenge in drug development. Solid dispersion (SD) techniques offer an effective strategy by which to enhance the bioavailability of BCS Class II drugs such as ivermectin (IVM). This study aimed to develop and validate stability-indicating analytical methods for the quantification of IVM and to evaluate the performance of the formulated SDs. A novel RP-HPLC and a UV spectrophotometric method were developed and validated in accordance with ICH guidelines. IVM SDs were prepared via physical mixing (PM), solvent evaporation (SE), and melt fusion (MF) using Poloxamer 188, Kollicoat^® IR, and PEG 6000 at respective ratios of 1:1, 1:3, and 1:5. Dissolution studies showed a marked enhancement in drug release from SDs prepared by SE and MF methods compared with pure IVM. Among all formulations, the Poloxamer 188-based binary SD prepared by the SE method at a 1:5 ratio exhibited the highest dissolution (98.55% at 60 min), with release kinetics following anomalous (non-Fickian) transport (n = 0.681) according to the Korsmeyer–Peppas model. Solid-state characterization evidenced by FTIR, DSC, TGA, and SEM confirmed the transformation of IVM from its crystalline form to an amorphous state. Future studies will focus on the in vivo evaluation of the optimized IVM SD formulations. Full article

Deposits of insoluble protein plaques, which are mostly composed of fibrils from disease-specific amyloid proteins, are histological markers of various human disorders. These range from non-neuropathic amyloidosis such as light chain amyloidosis or type II diabetes to well-known neuro-degenerative diseases such as Alzheimer’s Disease and Parkinson’s Disease. There are indications that these types of fibrillar suprastructures display biological activity distinct from the individual fibrils they are composed of. Yet, little is known about the mechanisms underlying the assembly of fibrillar suprastructures. An understanding of secondary fibril self-assembly into mesoscopic and macroscopic suprastructures is also critical for their application as novel biomaterial. The paucity of experimental data and theoretical models on fibrillar supra-assembly likely relates to the experimental and conceptual challenges in following this type of assembly on multiple length- and timescales, and in characterizing the distinct morphologies formed. Here, we report that the amyloid dye thioflavin T (ThT) is augmented during self-assembly of isolated lysozyme fibrils. We provide evidence that this augmentation of ThT fluorescence results from the unquenching of fibril-bound ThT during fibril binding. Combining ThT fluorescence, optical density, and fluorescence quenching kinetics with optical and electron microscopy, we propose that fibril self-assembly is driven by a transition from reaction-limited ordered assembly to diffusion-limited random cross-linking of fibrils. Full article

The increasing release of non-biodegradable heavy metals, particularly lead (Pb²⁺) and cadmium (Cd²⁺), poses severe risks to ecosystems and human health. Herein, we present a sustainable “treating-waste-with-waste” strategy that simultaneously addresses heavy-metal contamination in water and the accumulation of expanded perlite waste. Expanded perlite waste was directly converted into a high-purity, low-silica CHA zeolite via a simple, one-pot, template-free hydrothermal conversion. The resulting sodium-exchanged material (Na-CHA-p) demonstrated excellent Pb²⁺ and Cd²⁺ removal performance, featuring ultrafast adsorption kinetics (reaching equilibrium within 5 min for both ions), high adsorption capacities (555.6 mg·g⁻¹ for Pb²⁺ and 211.0 mg·g⁻¹ for Cd²⁺), and superior selectivity. This study demonstrates an efficient pathway for the high-value utilization of perlite waste and highlights the strong potential of waste-derived CHA zeolites as advanced adsorbents for heavy-metal wastewater remediation. Full article