Search Results (99,516)

Carbon fiber-reinforced resin matrix composites (CFRC) are extensively used in aerospace, automotive manufacturing, and sports equipment. However, the brittle nature of the resin matrix causes CFRC to exhibit severe vibrations and noise under dry friction conditions. Enhancing the intrinsic damping properties of the resin matrix serves as a fundamental and effective strategy to mitigate vibration and noise radiation in composite components. This study systematically investigates high-temperature co-curing damping composites using co-curing technology, aiming to improve the mechanical performance and damping characteristics of traditional fiber-reinforced epoxy resin composites. A novel carbon fiber-reinforced terminal carboxyl nitrile epoxy pre-polymer composite material demonstrates both stable chemical properties and excellent high-temperature resistance. Through formulation adjustments, the curing temperature and time of epoxy resin are matched with those of the terminal carboxyl nitrile epoxy pre-polymer. The performance of epoxy carbon fiber composites was evaluated through tensile tests, flexural tests, impact tests, infrared spectroscopy, thermogravimetric analysis, dynamic mechanical analysis, scanning electron microscopy, and X-ray diffraction. Results show that blending epoxy resin with terminal carboxyl nitrile liquid rubber enhances energy dissipation by increasing intermolecular friction and hydrogen bonding interactions. The damping ratio of epoxy resin-based carbon fiber composites reaches as high as 1.67%. Tensile strength, flexural strength, and impact strength reach 1968 MPa, 1343 MPa, and 127 kJ/m², respectively. The addition of terminal carboxylated nitrile liquid rubber facilitates the formation of continuous friction membranes, enhancing friction stability. Tensile tests demonstrate that carbon fiber composites containing 25% terminal carboxylated nitrile liquid rubber outperforms other formulations. As evidenced by impact tests, the performance of the prepared composites is superior to that of other configurations. Dynamic mechanical analysis indicates that the 25% rubber-containing composites exhibit enhanced damping characteristics and higher loss modulus. Experimental results confirm that this study advances the development of functional composites for vibration reduction and noise control applications. Full article

Magnesium phosphate cement (MPC) is widely used in rapid repair applications due to its fast setting, high early strength, and high-temperature resistance. However, the high cost of magnesium oxide (MgO) and the rapid hydration reaction make it challenging to control the setting time. In this study, steel slag powder (SSP) and ground granulated blast furnace slag (GGBS) were incorporated to partially replace MgO. The reactivity of SSP and GGBS was enhanced by an alkaline activator, promoting the dissolution of their glassy phases, which facilitated the formation of C-(A)-S-H gels and improved the performance of MPC. Experimental methods, including compressive strength testing, water resistance measurements, X-ray diffraction (XRD), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), mercury intrusion porosimetry (MIP), and thermogravimetric analysis (TG), were used to evaluate the 28-day compressive strength and the microstructural characteristics of the modified MPC. When both SSP and GGBS were incorporated at 10 wt.%, the modified MPC achieved a 7-day compressive strength of 37.2 MPa, with the 28-day strength increasing to 50.2 MPa. The addition of an alkali activator with a modulus of 1.3 significantly boosted the 28-day strength to 62.3 MPa, while maintaining high flowability (215 mm). Microscopic characterization revealed that C₂S and C₃S in SSP undergo continuous hydration under alkaline conditions, while reactive silica-aluminum in GGBS reacted with phosphate to form a water-resistant C-(A)-S-H gel phase, optimizing the pore structure of MPC. This study provides a novel approach to developing low-cost, high-durability modified MPC with improved performance. Full article

Carbon monoxide (CO) is a key component of syngas and an important intermediate in the chemical, metallurgical, heavy, and food industries. Although mainly associated with thermochemical processes, CO can also be generated during composting, offering an environmentally friendly biological alternative. This study assessed the potential for CO production during laboratory-scale composting of seven selected organic waste fractions: coffee grounds, green tea leaves/grounds, wheat straw, grass cuttings, branches, food waste, and a biowaste mixture with an optimal C/N ratio. Composting was carried out under laboratory conditions at 45 °C for 14 days, with daily passive aeration and monitoring of CO, CO₂, and O₂ concentrations in the reactor headspace. CO production kinetics were calculated for each substrate, and the CO mass yield was determined in each bioreactor. The study confirmed the CO generation potential of the analyzed organic waste fractions. The highest CO production was observed for grass cuttings (max. 2000 ppm, 1.21 mg), biowaste mix (2000 ppm, 0.82 mg), and wheat straw (1180 ppm, 0.24 mg). Grass cuttings exhibited the highest average reaction rate (3991.1 ppm·d⁻¹) and the most rapid process (2.920 d⁻¹). Fungal colonization was visibly present in the most CO-productive reactors, suggesting a role of fungal metabolism in CO formation. Full article

CaCO₃ and NaHCO₃, respectively serving as chemical leavening agents, can promote the expansion of protein or starch extrudates, thereby forming a porous structure. However, the characteristics of this porous structure under the combined regulation of CaCO₃ and NaHCO₃ remained unclear. The results indicated that increasing the proportion of NaHCO₃ promoted the expansion of the extruded protein–starch gel network, with its expansion ratio significantly increasing from 2.29 to 3.17 (p < 0.05). This expansion resulted in larger pores, which corroborated the observed significant increase in water holding capacity (WHC). Conversely, an increase in the proportion of CaCO₃ led to a denser porous structure accompanied by a reduction in WHC. Meanwhile, the extrudate with a CaCO₃/NaHCO₃ ratio of 0:2 exhibited the lowest hardness, measuring 8.87 N. As the proportion of NaHCO₃ increased, the pH shifted toward the alkaline range. This increase in pH enhanced the flexibility of the protein structure, leading to a significant rise in the proportion of disordered structures in the protein secondary structure, such as random coil and β-sheet, which facilitated the formation of an elastic gel network. In conclusion, both CaCO₃ and NaHCO₃ significantly modulated the porous structure of the protein–starch gel network formed during extrusion. This provides a new perspective for investigating the relationship between the protein–starch gel network and the quality characteristics of extruded products. Full article

Atomic oxygen in low Earth orbit erodes polyimide, increasing surface roughness and degrading performance. The reactive species scission polymer chains and remove surface material, exposing fresh sites that accelerate further attack and disrupt thermal, electrical, and mechanical functions. In this paper, we evaluate nanoscale reinforcements of polyimide with graphene and metal oxides under controlled atomic oxygen exposure equivalent to 145 days at a 550 km orbit. Graphene with a thickness of few nanometers and particle size less than 2 µm, and metal oxides zirconia, zinc oxide, and titania with particle size less than 100 nm were investigated. Hybrids containing graphene plus metal oxide at a 1:1 ratio and a total loading of 0.75 wt% increased roughness relative to neat polyimide, with graphene-zirconia showing a rise of +121 percent, graphene-zinc oxide +10 percent, and graphene–titania +20 percent. The behavior is consistent with agglomeration, incomplete dispersion, and interfacial mismatch that hinder uniform blocking of atomic oxygen and limit formation of protective oxygenated groups. In contrast, single-filler composites at 0.75 wt% reduced average roughness, with graphene lowering S_a by about 59 percent, zirconia by about 51%, titania by about 47%, and zinc oxide by about 47%. Varying graphene loading from 0.25 to 0.75 wt% diminished erosive features at the higher end, but atomic force microscopy revealed isolated tall peaks at 0.75 wt%, indicating localized restacking or agglomeration. Mechanical testing of graphene-reinforced coatings on fiberglass showed a similar trade-off, with tensile strength around 23 MPa and peak load greater than 50 N at 0.5 wt% compared to about 21 MPa and 40 N at 0.75 wt%, while strain at break remained comparable. These results define practical limits for nanoparticle reinforcement in polyimide, linking filler identity, loading, and dispersion quality to atomic oxygen response and sustained function in LEO. Full article

Land degradation (LD) is an emerging threat of the decade that is not only deteriorating arable lands globally but also threatening global ecosystem sustainability. Therefore, the intensification of LD has stimulated global governing bodies and researchers to undertake initiatives against this dilemma through sustainable and eco-friendly approaches. Geographical mapping is critical in analysing land formation, soil composition and land use patterns, subsequently facilitating data-driven planning for soil conservation. In this review, Geographic Information System (GIS) technology, combined with Shuttle Radar Topography Mission (SRTM) data, is used to explore soil properties and land use patterns across Saudi Arabia, with a focus on soil types, soil thickness, and soil uses. Spatial analyses indicate that the most predominant soil type in the country is sandy, followed by loam and sandy loam. The soil depth distribution exhibits a notably bimodal pattern, with large areas characterized by shallow soils (0–4 m) and deep soils (43–50 m). These spatial visualizations provide valuable insights into soil heterogeneity, supporting evidence-based, site-specific strategies for sustainable land management. This study also outlines the major land degradation pathways affecting arable lands in Saudi Arabia and describes how these pathways can be used to assess the extent of land loss. Besides land loss pathways, the current study also explains the most suitable mitigation strategies, including mulching, cover cropping, and agroforestry, as well as how international governing bodies like the UNDP, UNEP, FAO, and World Bank can contribute to the mitigation of LD in Saudi Arabia. However, further studies are required to assess the intensity of these solutions for each soil type and thickness under different climatic conditions. Full article

A mechanistically unusual CuCN-catalyzed electrophilic amidation of Grignard reagents with N-H containing O-allyl- and O-benzyl-hydroxamic acid derivatives as leaving groups to give secondary amides is reported. Computational DFT examination of the reaction points to the intermediate formation of electrophilic acyl nitrenoid species triggered by the presence of CuCN and magnesium salts. The work also provides some experimental evidence about the molecular composition and reactivity of organomagnesium cuprates, the structural nature of which remains a subject of ongoing debate. Full article

An improved depleting sand fracture model was derived in this work using Finite Element Methods, taking into consideration the effect of pore pressure and production on in situ stresses. Sets of governing equations from the commercial finite element simulator COMSOL Multiphysics were used to obtain a model that compares well with the existing fracture model, mainly based on the Mohr–Coulomb failure criterion. The model uniquely couples reservoir depletion-induced stress evolution with fracture initiation and propagation within a unified finite element framework. A constant overburden load was used since its value majorly depends on depth, and the formation is assumed to be fixed at the bottom. The reservoir is assumed to be depleting at a constant rate with no water injection to assist pressure, with an average porosity of 25% and an average permeability of 251 mD at the beginning of production. The reservoir compacted during production, and in turn, porosity and permeability were reduced over the years of observation. Fracturing was observed to be much easier for the depleted reservoir, since horizontal stresses, which might have created friction, are reduced during reservoir production, signifying that for depleted reservoirs, a small fracture pressure is required. Created fractures are observed to propagate in the direction of the maximum horizontal stress and perpendicular to the direction of the minimum horizontal stress. Full article

Ovarian cancer, the most lethal type of tumour of the female reproductive system, severely threatens women’s life and health. Despite paclitaxel being a key chemotherapeutic agent in the standard treatment for ovarian cancer, the majority of patients eventually develop resistance to paclitaxel, constituting a significant obstacle to successful treatment. KIF26B, a kinesin family protein, is involved in various cancers, but its role in ovarian cancer and chemotherapy resistance is unclear. In this study, we evaluated the role of KIF26B in drug-resistant ovarian cancer and the underlying mechanisms. Bioinformatics analysis revealed that KIF26B was highly expressed in ovarian cancer tissues and was associated with poor clinical characteristics. Moreover, KIF26B expression was consistently high in chemotherapy-resistant tissues across multiple treatment subgroups, with ROC curve analyses confirming its predictive power for chemoresistance, particularly in advanced serous ovarian cancer. To further investigate the role of KIF26B in ovarian cancer resistance, the effects of KIF26B on cell proliferation, colony formation, the cell cycle, apoptosis, and microtubule polymerization under paclitaxel treatment were assessed. KIF26B knockdown significantly reduced paclitaxel resistance in ovarian cancer cells, inhibited cell proliferation, and promoted apoptosis. Furthermore, KIF26B interference induced cell cycle arrest and altered microtubule polymerization dynamics in paclitaxel-resistant cells. Additionally, our analyses revealed a negative correlation between KIF26B and SLC7A11 in ovarian cancer, particularly in chemoresistant tissues. Combined KIF26B and SLC7A11 expression provided stronger prognostic value than either gene alone did, and functional assays demonstrated that SLC7A11 contributed to the regulation of the KIF26B-mediated paclitaxel response. Overall, our results indicate that KIF26B is crucial for ovarian cancer progression and chemotherapy resistance, likely through SLC7A11 regulation. KIF26B may serve as a potential therapeutic target for overcoming paclitaxel resistance. Full article

Magnesium alloys require protective surface coatings for widespread application, with micro-arc oxidation (MAO) being a prominent technique. However, conventional MAO coatings are typically gray or light-colored, necessitating secondary treatments for specific colors like black, which complicates the process. This study aims to develop a one-step method for fabricating black MAO coatings on AZ31 magnesium alloy by introducing cupric pyrophosphate (Cu₂P₂O₇) as a colorant into a silicate-based electrolyte. As the Cu₂P₂O₇ concentration increased from 0 to 5 g/L, the coating color transitioned from grayish-white to pink, then brownish-black, achieving a uniform black appearance at 4–5 g/L. XPS and EDS analyses confirmed the incorporation of copper as CuO, identified as the primary coloring agent. XRD indicated that the phase composition remained MgO, MgSiO₃, and Mg, although the MgO content decreased. Microstructural analysis showed that an optimal concentration of 4 g/L enhanced coating compactness by thickening the dense layer and reducing pore size. However, electrochemical tests revealed that the incorporation of CuO significantly increased the corrosion current density, thereby reducing the coating’s corrosion resistance compared to the unmodified coating. This work successfully demonstrates the one-step fabrication of black MAO coatings, elucidates the coloration mechanism involving CuO formation, and provides insights into the trade-off between aesthetic functionalization and corrosion performance. Full article

Black crusts are multilayered alteration products that develop on historic masonry exposed to urban pollution. This study investigates the west enclosure wall of the XVII^th-century Golia Monastery in Iași, Romania—located along a busy traffic corridor—and presents multi-analytical results on two lime-based mortar fragments exhibiting well-developed blackened surface layers. Both the exposed (blackened) finishes and protected verso areas were analyzed using portable X-ray fluorescence (pXRF), scanning electron microscopy with energy-dispersive X-ray analysis (SEM–EDX), micro-FTIR spectroscopy, X-ray diffraction (XRD), CIE Lab colorimetry and optical microscopy (OM). The data reveal gypsum-rich surface layers enriched in traffic-derived particles, including metal oxides and soot, with marked contrasts relative to the minimally altered verso. Handheld XRF and SEM–EDX indicate elevated sulfur and associated traffic-related elements within porous gypsum matrices, while FTIR and XRD consistently identify calcium sulfate as the dominant secondary phase. Colorimetric measurements additionally document pronounced lightness loss and visible darkening on exposed surfaces. These results demonstrate the onset of directional sulfation and black crust formation on mortars under urban pollution pressure and establish an integrated analytical protocol for diagnosing black crusts on historic lime mortars in urban heritage settings. Full article

Subsoil (30–100 cm) soil organic carbon (SOC) is a poorly constrained but potentially significant component of terrestrial carbon budgets. While controls on subsoil SOC are likely to differ from those affecting topsoil, few studies have quantified them. This study quantified subsoil (30–100 cm) SOC stocks and identified the controls on its spatial distribution across perennial grazing systems in northeast New South Wales, Australia. SOC was measured to 1 m depth across 54 long-term perennial pasture grazing paddocks on nine farms. A Random Forest regression model was then used to determine the relationship between subsoil SOC and drivers represented by the scorpan model of soil formation. Subsoil SOC contributed ~50% of total SOC stocks in the top metre of soil, with a median of 65.8 t ha⁻¹ stored in subsoil. Our study found that drivers of SOC input and turnover (subsoil total nitrogen, 10–30 cm SOC content, and climate), as well as pedogenic processes influencing SOC stabilisation (weathering index), were the most important factors in the determination of subsoil SOC content. This contrasts with previous findings where abiotic factors linked to parent material and soil properties were the major controls on subsoil SOC distribution and highlights links between both input and stabilisation in perennial grazing systems. Full article

The relative position of the oxime group within pharmaceutically relevant pyridinium oximes is a pivotal factor that governs their intrinsic physicochemical properties and their biological reactivity. However, studies providing in-depth, molecular-level insight into these structure–reactivity relationships are still limited. In this work, we present an integrated experimental and computational study of N-methylpyridinium-2-aldoxime chloride (PAM2-Cl), N-methylpyridinium-3-aldoxime iodide (PAM3-I), and N-methylpyridinium-4-aldoxime iodide (PAM4-I), aimed at elucidating discrete differences in their ionization behavior, electronic structure, σ-donor properties, and nucleophilicity. The crystal structure of PAM3-I was determined by X-ray diffraction. Comparative structural and spectroscopic (UV–Vis, NMR, IR) analyses elucidated the structural and electronic effects arising from the position of the oxime group. Kinetic studies of substitution reactions with aquapentacyanoferrate(II) in aqueous solution enabled the determination of pentacyano(PAM)ferrate(II) formation and dissociation rate constants, coordination modes, pK_a values of the coordinated ligands, complex stability constants, and σ-donating capabilities. The DFT-based analysis of atomic charge distribution transcended experimental limitations, offering a new perspective on electronic structure-related properties. This study presents the first side-by-side, internally consistent structure–reactivity map across PAM2, PAM3, and PAM4 isomers that triangulates crystallography, UV–Vis-derived pK_a values, substitution kinetics, and DFT descriptors in a single framework. Full article

The world population is increasing exponentially and is expected to reach 9.2 billion people by 2040, intensifying pressures on food systems and raising concerns regarding food security and environmental sustainability. In response, plant-based and microbially sourced meat and dairy analogues have emerged as alternatives to animal-derived foods. These next-generation products rely heavily on fat substitutes to replicate the sensory and functional roles of animal fats, which not only influence flavour, texture, and consumer acceptance but also play a critical role in digestion and the absorption of lipophilic nutrients. This review advances a structure–interface–digestion framework for understanding fat substitutes in meat and dairy analogues, in which lipid composition and supramolecular organization jointly determine digestive fate and nutritional functionality. Rather than acting solely as sensory replacers, fat analogues regulate lipolysis kinetics, mixed micelle formation, and the bioaccessibility of lipophilic nutrients through key parameters including fatty acid chain length, degree of saturation, physical state, and interfacial architecture. Within this framework, plant and microbially derived lipid systems are not functionally interchangeable with animal fats and therefore require purposeful structural design to ensure effective digestion and nutrient delivery. By integrating insights from food sciences, nutrition, and biotechnology, this review highlights the necessity of rationally engineered fat analogue systems that reconcile sustainability constraints with sensory performance and optimal nutritional efficacy. Full article

This study examines how artificial intelligence (AI) contributes to contemporary processes of authenticity evaluation by functioning as a multimodal diagnostic cue in consumer decision-making. Drawing on survey data collected from 468 visitors at Terra Madre Salone del Gusto in Turin, Italy, the study tests a structural model comprising five latent constructs: Authenticity Trust, Perceived AI Usefulness and Diagnosticity, Multimodal Value, User Engagement, and Behavioural Intentions. The findings indicate that heritage-based and institutional authenticity cues remain foundational in consumers’ evaluations, but are increasingly associated with interaction with AI-supported information perceived as credible and diagnostically informative. Multimodal inputs—particularly the integration of textual, visual, and auditory narratives—are positively associated with perceived multimodal value and user engagement within AI-supported evaluation. Experiential enjoyment during interaction with the AI system is positively associated with behavioural intentions to adopt AI-supported evaluation tools, while behavioural intentions encompass both adoption readiness and a stated willingness to pay a premium for products perceived as authentic. Although the use of a convenience sample limits generalisability, the results highlight the broader potential of multimodal AI systems to enhance perceived diagnostic clarity and evaluative confidence in complex cultural and consumer environments. Conceptually, the study advances the notion of augmented authenticity, defined as a hybrid evaluative process in which tradition-based trust mechanisms are interpreted in relation to perceived AI diagnosticity and multimodal coherence. By situating AI within culturally embedded processes of meaning-making rather than purely instrumental evaluation, the findings contribute to interdisciplinary debates on technology-supported trust processes, consumer judgement, and the societal implications of AI-supported decision-making. Full article