Search Results (9,401)

Hybrid silica xerogels functionalised with chlorinated organosilanes combine tunable porosity and surface chemistry, rendering them attractive for applications in sensing, membrane technology, and photonics. This study quantitatively investigates the thermal decomposition kinetics of organochlorinated xerogels and correlates with volatile compounds previously identified via Thermogravimetric Analysis (TGA) coupled to Fourier-Transform Infrared Spectroscopy (FT–IR) and Gas Chromatography coupled with Mass Spectrometry (GC–MS). The xerogels were synthesised via the sol–gel process using organochlorinated alkoxysilane precursors and yielded highly condensed nanostructures in which the precursor nature strongly influences the morphology and textural properties. In this study, the molar percentage of the organochlorinated compounds was fixed at 10%. Standard N₂ adsorption-desorption isotherm at 77 K revealed that increasing the precursor content systematically decreased the specific surface area and pore volume of the materials while promoting the formation of periodic domains, which are observed even at low organosilane molar percentages. Thermal characterisation via TGA/FT–IR/GC–MS revealed at least two main decomposition stages, with thermal stability following the order of 4-chlorophenyl > chloromethyl > 3–chloropropyl > 2–chloroethyl. This study focuses on kinetic and mechanistic insights in the thermal decomposition process through the Flynn–Wall–Ozawa isoconversional method and Criado master plots, using TGA/Differential Scanning Calorimetry (DSC) measurements under nitrogen at multiple heating rates (5, 10, 20, 30, and 40 K min⁻¹), which revealed activation energies ranging from 53 to 290 kJ mol⁻¹. Demonstrating that the chlorinated organosilane precursor directly controls both the textural properties and thermal behaviour of the resulting silica materials, with aromatic groups providing superior thermal stability compared to aliphatic chains. These quantitative kinetic insights provide a predictive framework for designing thermally stable hybrid materials while ensuring safe processing conditions to prevent hazardous volatile release. Full article

Background: Rapid pathogen detection is crucial for the timely containment of outbreaks, particularly for respiratory infectious diseases which are highly transmissible and possess high epidemic potential. Methods: We developed a sensitive reverse transcription recombinase-aided amplification (RT-RAA) assay for the rapid detection of six common respiratory viruses: respiratory syncytial virus type A (RSV A), influenza A virus (Flu A), influenza B virus (Flu B), human parainfluenza virus (HPIV), SARS-CoV-2 and adenovirus (ADV). The assay employs a single, standardized protocol for the on-demand detection of any one of the six targets. Its performance was validated using nucleic acid standards and clinical pharyngeal swab specimens. Results: The assay enables rapid detection within 20 min at 39 °C using a portable, self-powered device. It demonstrated high sensitivity, with detection limits below 10³ copies/mL for all targets and as low as 10¹ copies/mL for ADV. Cross-reactivity testing with 21 other pathogens confirmed excellent specificity. Validation with 85 clinical samples showed 100% concordance with RT-PCR, while offering significantly faster results and enhanced portability compared to RT-PCR. Conclusions: This sensitive, specific, and user-friendly RT-RAA assay provides a robust tool for rapid detection of respiratory viruses, particularly suitable for deployment in resource-limited settings and point-of-care testing during outbreaks. Full article

To address the fluctuation and instability of renewable power generation and the steady-state demands of chemical processes, a single-channel, non-isothermal computational fluid dynamics 3D model was developed. This model explicitly incorporates the coupling effects of electrochemical reactions, two-phase flow, and heat transfer. Subsequently, the influence of key operating parameters on proton exchange membrane water electrolyzer (PEMWE) system performance was investigated. The model accurately predicts the current–voltage polarization curve and has been validated against experimental data. Furthermore, the CFD model was employed to investigate the coupled effects of several key parameters—including operating temperature, cathode pressure, membrane thickness, porosity of the porous transport layer, and water inlet rate—on the overall electrolysis performance. Based on the numerical simulation results, the evolution of the ohmic polarization curve under temperature gradient, the block effect of bubble transport under high pressure, and the influence mechanism of the microstructure of the multi-space transport layer on gas–liquid, two-phase flow distribution are mainly discussed. Operational strategy analysis indicates that the high-efficiency mode (4.3–4.5 kWh/Nm³) is suitable for renewable energy consumption scenarios, while the economy mode (4.7 kWh/Nm³) reduces compression energy consumption by 23% through pressure–temperature synergistic optimization, achieving energy consumption alignment with green ammonia synthesis processes. This provides theoretical support for the optimization design and dynamic regulation of proton exchange membrane water electrolyzers. Full article

In this study, the potential use of Epsom salt production waste as a supplementary cementitious material was investigated. This acidic waste was neutralized with lime milk and used to replace up to 25 wt.% of Portland cement. The following research methods were employed: XRD, XRF, SEM, DSC-TG, and isothermal calorimetry. The waste neutralization process was found to proceed consistently, producing a neutral material (pH = 7.5) composed of amorphous silicon compounds with a negligible impurity of crystalline antigorite. Consequently, this material exhibits very high pozzolanic activity. The neutralized Epsom salt production waste accelerates the early hydration of Portland cement and promotes an intense pozzolanic reaction. This new material is a highly effective supplementary cementitious material, capable of replacing up to 25 wt.% of Portland cement without reducing its strength class. Full article

End-of-life wind turbine blade accumulation is a growing global materials management problem and current industrial recycling routes for glass fiber-reinforced polymer composites remain limited in material recovery value. There is limited understanding on how to recover clean glass fibers while keeping thermal exposure and energy input low, and existing studies have not quantified whether very short isothermal thermal residence can still result in complete matrix removal. The hypothesis of this study is that a mild two-step thermochemical sequence can recover clean glass fibers at lower temperature and near zero isothermal dwell if pyrolysis and oxidation are separated. We used wind-blade epoxy-based GFRP in a step-batch reactor and combined TGA-based thermodynamic mapping, short pyrolysis at 425 °C, and mild oxidation at 475 °C with controlled dwell from zero to thirty minutes. We applied model-free kinetics and machine learning methods to quantify activation energy trends as a function of conversion. The thermal treatment of 425 °C for zero minutes in nitrogen, followed by 475 °C for fifteen minutes in air, resulted in mechanically sound, visually clean white fibers. These fibers retained 76% of the original tensile strength and 88% of the Young’s modulus, which indicates the potential for energy-efficient GFRP recycling. The activation energy was found to be approximately 120 to 180 kJ mol⁻¹. These findings demonstrate energy lean recycling potential for GFRP and can inform future industrial scale thermochemical designs. Full article

Hexavalent chromium (Cr(VI)) is a carcinogenic and highly mobile pollutant in aquatic environments. In this study, three cerium-based metal–organic frameworks (Ce-UiO-66, Ce-UiO-66-NO₂, and Ce-MOF-808) were synthesized and evaluated for their ability to remove Cr(VI) from aqueous solutions. Among the frameworks studied, Ce-MOF-808 exhibited the highest adsorption capacity and was selected for detailed investigation. To elucidate its structure and adsorption behavior, Ce-MOF-808 was characterized using XRD, FT-IR, SEM-EDS, TG-DTA, XPS, and Zeta potential analyses. The zeta potential results showed that the adsorbent surface remained positively charged in the pH range of 2.8–8.6, enabling electrostatic attraction toward anionic chromate species. XPS further revealed valence transitions between Ce³⁺/Ce⁴⁺ and Cr(VI)/Cr(III), demonstrating the occurrence of partial redox transformation during adsorption. Batch experiments showed that the adsorption was strongly pH-dependent and favored acidic conditions (pH 2). The kinetics followed the pseudo-second-order model, whereas the isotherm data were better described by the Langmuir model, yielding a maximum adsorption capacity of 42.74 mg/g. Thermodynamic analysis indicated a spontaneous and exothermic process. Moreover, Ce-MOF-808 maintained high Cr(VI) uptake in real water samples, demonstrating its environmental applicability. Overall, Ce-MOF-808 is a promising redox-active adsorbent for efficient Cr(VI) removal in water treatment applications. Full article

Strip casting presents a sustainable route for producing advanced steels, such as high-strength low-alloy (HSLA) grades. This study investigated how early-stage isothermal holding (120–1800 s at 923 K) affects the evolution of cluster morphology and its subsequent impact on dislocation behavior and mechanical properties in a strip-cast Nb-bearing HSLA steel. Advanced characterization (atom probe tomography) revealed that prolonged holding promotes the growth of nanoscale Nb-(C,N) clusters and precipitates, accompanied by an increase in ferrite fraction. Remarkably, this evolution simultaneously enhances both strength and ductility. Enhanced ductility and sustained work hardening are linked to a higher density and volume fraction of nanoscale particles, which act as potent obstacles for dislocation nucleation and multiplication. These findings establish a critical link between cluster evolution and dislocation-mediated strengthening, providing a basis for optimizing strip-cast steels. Full article

Contamination of natural water sources with zinc ions poses serious ecological and health risks due to its toxicity and persistence. In this context, this study presents the preparation of new adsorbents based on acrylonitrile-divinylbenzene networks functionalized with aminophosphonate groups, selected for their strong chelating affinity towards Zn(II) ions. Both unmodified and functionalized materials were evaluated in adsorption experiments towards zinc ions. The adsorption capacity was evaluated as a function of the contact time and the initial zinc concentration. The functionalized adsorbents exhibited a significantly higher adsorption of zinc, attributed to the presence of aminophosphonate groups. In case of functionalisation with ethyl phosphonate group is achieved a maximum adsorption capacity of 101 mg/g. The equilibrium data followed the Langmuir isotherm, indicating monolayer adsorption, while the kinetic analysis followed the pseudo-second-order model, consistent with chemisorption. The optimal contact time was 60 min. Functionalized polymeric supports show strong potential for zinc ion removal, supporting their use in environmental remediation. Overall, the results demonstrate that aminophosphonate-functionalized polymers are highly effective adsorbents for the removal of zinc ions from contaminated waters. Full article

A novel mesoporous spherical chelating lignin-based adsorbent was successfully synthesized via inverse suspension polymerization using sulfate pine pulping black liquor as raw material, followed by graft copolymerization with acrylonitrile and subsequent amination. The obtained aminated cyanoethyl spherical lignin resin (ACSLR) exhibited a well-defined porous morphology and abundant active sites, as confirmed by SEM and FT-IR. Adsorption experiments demonstrated high Pb²⁺ uptake capacity (63.98 mg·g⁻¹) under optimal conditions (pH = 5.5, 2.0 g·L⁻¹ adsorbent dosage, and 150 mg·L⁻¹ initial concentration of Pb²⁺ solution). The adsorption process followed the Langmuir isotherm and pseudo-second-order kinetics, indicating monolayer chemisorption dominated by amino and cyano groups. This work provides a sustainable strategy for valorizing industrial lignin waste into efficient adsorbents for heavy metal removal, highlighting its potential for practical wastewater treatment applications. Full article

La-doped ZnO nanoclusters confined within mesoporous SBA-15 were synthesized using an impregnation–calcination method and evaluated for their visible-light-driven photocatalytic degradation of Rhodamine B (RhB). Small-angle X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the preservation of the 2D hexagonal mesostructure of SBA-15 post-loading. In contrast, wide-angle XRD and Fourier-transform infrared spectroscopy (FT-IR) analyses revealed that the incorporated ZnO existed predominantly as highly dispersed amorphous or ultrafine clusters within the mesopores. N₂ adsorption–desorption measurements exhibited Type IV isotherms with H1 hysteresis loops. Compared to pristine SBA-15, the specific surface area and pore volume of the composites decreased from 729.35 m² g⁻¹ to 521.32 m² g⁻¹ and from 1.09 cm³ g⁻¹ to 0.85 cm³ g⁻¹, respectively, accompanied by an apparent increase in the average pore diameter from 5.99 nm to 6.55 nm, attributed to non-uniform pore occupation. Under visible-light irradiation, the photocatalytic performance was highly dependent on the La doping level. Notably, the 5% La-ZnO/SBA-15 sample exhibited superior activity, achieving over 99% RhB removal within 40 min and demonstrating the highest apparent rate constant (k = 0.1152 min⁻¹), surpassing both undoped ZnO/SBA-15 (k = 0.0467 min⁻¹) and other doping levels. Reusability tests over four consecutive cycles showed a consistent degradation efficiency exceeding 93%, with only a ~7 percentage-point decline, indicating excellent structural stability and recyclability. Radical scavenging experiments identified h⁺, ·OH, and ·O₂⁻ as the primary reactive species. Furthermore, photoluminescence (PL) quenching observed at the optimal 5% La doping level suggested suppressed radiative recombination and enhanced charge carrier separation. Collectively, these results underscore the synergistic effect of La doping and mesoporous confinement in achieving fast, efficient, and recyclable photocatalytic degradation of organic pollutants. Full article

GH2132, an Ni–Cr–Fe-based superalloy for aero-engine components, exhibits hot workability that is highly sensitive to processing parameters. The hot deformation behavior of GH2132 alloy was investigated via isothermal compression (Gleeble-3500-GTC) over 850–1100 °C and 0.001–10 s⁻¹, combined with optical microscopy and EBSD characterization. A strain-compensated Arrhenius-type hyperbolic-sine model was established, achieving high predictive accuracy (R² = 0.9916; AARE = 3.86%) with an average activation energy Q = 446.2 kJ·mol⁻¹. Flow stress decreases with increasing temperature and increases with strain rate, while microstructural softening transitions from dynamic recovery to complete dynamic recrystallization at higher temperatures and lower strain rates. Three-dimensional power-dissipation and hot-processing maps (Dynamic Materials Model) delineate safe domains and instability regions, identifying an optimal window of 1000–1100 °C at 0.001–0.01 s⁻¹ and instability at 850–900 °C with 0.01–0.1 s⁻¹. These results provide guidance for selecting parameters for hot deformation behavior during thermomechanical processing of GH2132. Full article

Swirl-stabilized combustors are central to gas turbine technology, where the swirl number critically determines flow structure and combustion stability. This work systematically investigates the isothermal flow in a dual-swirl combustor, focusing on two primary objectives: evaluating advanced turbulence models and quantifying the impact of geometric-induced swirl number variations. Large Eddy Simulation (LES), Detached Eddy Simulation (DES), Scale-Adaptive Simulation (SAS), and the k-$\omega$ SST RANS model are compared against experimental data. The results suggest that while all models capture the mean recirculation zones, the scale-resolving approaches (LES, DES, SAS) more accurately predict the unsteady dynamics, such as shear layer fluctuations and the precessing vortex core, which are challenging for the RANS model. Furthermore, a parametric study of vane angles (60° to 70°) reveals a non-monotonic relationship between geometry and the resulting swirl number, attributed to internal flow separation. An intermediate swirl number range (S ≈ 0.79) was found to promote stable and coherent recirculation zones, whereas higher swirl numbers led to more intermittent flow structures. These findings may provide practical guidance for selecting turbulence models and optimizing swirler geometry in the design of modern combustors. Full article

Continuous cooling transformation (CCT) diagrams for two thermo-mechanically controlled processed (TMCP) steels were produced using a modified Johnson–Mehl–Avrami–Kolmogorov (JMAK) model, which accounted for the simultaneous transformation of multiple phases under non-isothermal conditions. A basin hopping algorithm was used to sequentially optimize the model parameters for each phase. Samples were prepared using a dilatometer which replicated the deformation and cooling rates experienced during TMCP. Scanning electron microscopy (SEM) and electron back-scattered diffraction (EBSD) were used to identify and quantify the phases present in each steel. CCT diagrams illustrating the start and stop temperatures of each phase were constructed for both steel samples. Through inclusion of the stop temperatures of each phase transformation, the utility of the CCT diagrams were expanded. This was done by introducing the possibility of applying the Scheil additive principle with respect to the beginning and end of each phase transformation. With this modification, the CCT diagrams are now more appropriately suited to predict the phase transformations that occur on the ROT, where non-continuous cooling occurs. Full article

Salmonella enterica serovar Gallinarum is a non-motile serovar and is the causative agent of fowl typhoid, and poses a major challenge to poultry production, particularly where rapid diagnostics are lacking. Existing methods are either time-consuming or fail to distinguish motile from non-motile serotypes. We developed a dual-target colorimetric LAMP that detects Salmonella spp. via invA and discriminates S. Gallinarum via TRX (a taxon-restricted sequence), using two separate singleplex reactions. Specificity testing confirmed 100% accuracy, with exclusive amplification of S. Gallinarum through TRX. Analytical sensitivity was comparable to real-time PCR, detecting down to 2.41 CFU/µL (invA) and 1.65 CFU/µL (TRX). Applied to cloacal swabs from experimentally infected chickens (n = 12), the assay consistently outperformed bacteriological culture, detecting up to 25% more positives during early infection when bacterial loads were low or cells were non-culturable. This dual-target LAMP provides a rapid, sensitive, and serovar-discriminating diagnostic tool with strong potential for point-of-care use and real-time surveillance in poultry farms, thereby improving sanitary control of fowl typhoid and reducing associated economic losses. Full article

Advanced technologies, such as antimicrobial coatings on food contact surfaces (FCSs), are critical to prevent the occurrence of food-contaminating bacteria. Titanium dioxide coatings were fabricated by the sol–gel method on stainless steel following an experiment consisting of eight different combinations of these synthetic parameters: type of protocol (method), amount of surfactant, aging time, spinning speed, and sintering temperature. Hardness and elastic modulus values of the eight coating combinations were assessed by nanoindentation, and their values were statistically analyzed to determine which protocol and sintering temperature were significant influencing factors. Additional experimental points were procured to obtain trends relating sintering temperature to hardness and elastic modulus. Within the experimental range studied, hardness monotonically increased with sintering temperature, reaching its maximum value at 595 °C, while elastic modulus attained a maximum value at 640 °C. These maxima’s isotherms were overlapped on the coating’s photocatalytic activity contour plot to explore which combinations of protocol, aging time, and sintering temperature yielded optimal photocatalytic activity, hardness, and elastic modulus. The optimized coating was tested against two representative foodborne pathogens, Escherichia coli O157:H7 and Staphylococcus aureus cells and their biofilms, and was characterized by nanoindentation, scanning electron microscopy, and X-ray diffraction. The properties of the coating, as found in this study, present evidence for its potential FCS applications. Full article