Search Results (1,079)

Approximately 5–33% of the dates growing in Saudi Arabia are downgraded to low-quality fruit that either goes to waste or is used to make animal feed, which is considered a potential feedstock abundant in sugar. By a thorough comparative study, this study evaluated the up-cycling of low-quality Saudi dates (Wannana, Shagra, Sabbaka, Barhi, Saqai, Khalas and Sukkari) as fermentation substrates for xanthan gum production by Xanthomonas campestris. Pure glucose, pure sucrose, and a commercial standard were used as a baseline. The sole carbon source was date juice (≈12.5–17 °Brix) in a batch aerobic fermentation conducted at the standard conditions of temperature (30 °C), speed 180 rpm, and time (120 h). The xanthan gum was quantified and tested for its properties like functional groups (FTIR), color, thermal behavior (TGA and DSC), and rheology in the form of both steady- and dynamic-shear rheology. Xanthan gum was produced in the range 5.60–7.77 g L⁻¹ by the date-based substrates with Barhi (7.77 g L⁻¹) and Saqai (7.58 g L⁻¹) surpassing those of the glucose (6.68 g L⁻¹) and sucrose (6.23 g L⁻¹) controls. FTIR spectra of date-derived gums were almost identical to that of the commercial standard, indicating that their functional groups and the primary structure were very similar. In addition, the date-derived powders were darker and yellower (L* 61.09, 71.00; whiteness index 54.92, 63.34) than the commercial gum (L* 84.71; whiteness index 78.19). This is likely attributed to the presence of residue date pigmentation and products of Maillard and caramelization. Thermogravimetric analyses revealed that the breakdown of materials occurred in two stages, of which the char residue of the date-derived gums was much higher for those degraded at 500 °C (48.93, 54.05%) versus that of the commercial reference (33.49%), which is to be interpreted as a better ability of the former to resist thermal degradation. All solutions acted as pseudoplastic, shear-thinning liquids (flow behavior index n < 1); the consistency coefficient (K) rose with concentration and fell with temperature. The activation energy varied between 9.98 kJ mol⁻¹ (commercial) and 29.39 kJ mol⁻¹ (Saqai). Overall, low-quality Saudi dates can be considered a technically and economically viable, sustainable, and low-cost carbon substrate suitable for upcycling to produce xanthan gum, which is safe for use as a food additive. Full article

Background/Objectives: Periodontitis is characterized by the gradual breakdown of tooth-supporting tissues, including the periodontal ligament and alveolar bone, while current regenerative strategies remain limited. Palm mixed-carotenes (PMC), a natural carotenoid-rich compound with antioxidant and cytoprotective properties, may have potential in periodontal regenerative research. However, its effects on human periodontal ligament stem cells (hPDLSCs) remain underexplored. This study evaluated the effects of PMC on hPDLSC viability, wound closure, and osteogenic- and bone remodeling-related molecular responses. Methods: Primary hPDLSCs were isolated, characterized, and treated with PMC at concentrations ranging from 0 to 100 μg/mL. Cell viability was evaluated using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, wound closure using a wound-scratch assay, gene expression of osteoprotegerin (OPG), osteopontin (OPN), and osteocalcin (OCN) using real-time polymerase chain reaction (RT-qPCR), and secreted protein levels using enzyme-linked immunosorbent assay (ELISA). Results: PMC showed a biphasic viability response, with 6.25 μg/mL producing the most favorable effect by increasing the cell viability to 111.6% relative to the negative control. This concentration was selected, together with 12.5 μg/mL, for subsequent assays. In the wound-scratch assay, 6.25 μg/mL PMC significantly enhanced wound closure at 48 and 72 h, reaching 75.17% at 72 h compared with 52.69% in the negative control. Gene expression analysis showed that 6.25 μg/mL PMC significantly upregulated OPG mRNA expression compared with the negative control, 12.5 μg/mL PMC, and positive control groups. OPN and OCN showed limited responses, and PMC did not significantly increase secreted OPG or OCN protein levels. Conclusions: Overall, PMC at 6.25 μg/mL demonstrated the most favorable response in hPDLSCs, suggesting its potential as a bioactive candidate for further periodontal regenerative research. Full article

Highland barley (HB) is nutritionally rich but its low gluten content limits its use in wheat-based staple products. This study systematically compared the effects of substituting wheat flour with superfine grinding modified highland barley flour (SG-HBF) or ultrasonically modified highland barley flour (US-HBF) at 10–30% ratios on the properties and quality of wheat flour, dough, and noodles. Results showed that SG-HBF reduced the peak viscosity, breakdown, and setback value of the blended flour, enhanced its thermal stability and anti-aging properties; whereas, US-HBF significantly increased the viscosity. Noodles maintained good sensory and cooking quality when SG-HBF ≤ 15% or US-HBF ≤ 20%. Beyond these thresholds, the cooking loss increased sharply and overall acceptability declined. At the same substitution ratio, SG-HBF outperformed US-HBF in terms of water distribution, cooking loss, and sensory scores, offering better processing efficiency, while US-HBF provides higher springiness and lower broken rate, suitable for products requiring noodle integrity. This study provides a reference for the application of modified HBF in wheat-based products. Full article

Electrochemical corrosion is one of the main causes of degradation of substation grounding devices and directly impacts the operational reliability of electric power facilities. Despite numerous studies on individual corrosion factors, comprehensive models considering the combined effects of soil physical and chemical properties and electrical operating conditions remain limited. This study analyzes emergency situations associated with grounding system failures and examines the effect of the main factors of electrochemical corrosion, including chloride ion concentration, soil moisture, environmental acidity, seasonal temperature changes, and leakage currents. Based on Faraday’s law, a mathematical model of electrochemical corrosion rate is proposed that combines the influence of the factors considered through correction factors. For practical implementation, an algorithm for the dynamic assessment of degradation of grounding system elements has been developed. The proposed model predicts changes in the cross-sectional area of grounding device elements, changes in grounding resistance, and the occurrence of potentially hazardous operating conditions. The developed algorithm assesses the risk of exceeding the permissible grounding potential, violating thermal withstand, the occurrence of hazardous step voltages, insulating breakdown, and disrupting the selectivity of relay protection devices. Full article

In the current paper, pulmonary emphysema is hypothesized to emerge from a nonlinear breakdown of cooperation across two tightly coupled systems: the extracellular matrix (ECM) crosslink network and the cellular populations responsible for its maintenance. To formalize this concept, we construct a game-theoretic model that unifies the mechanical failure, inflammatory changes, and percolation-driven tissue collapse that are recognized features of the disease. At the ECM level, elastin and collagen crosslinks are modeled as players in an iterated Prisoner’s Dilemma, where cooperation corresponds to maintaining structural integrity, and defection corresponds to rupture under mechanical stress. At the cellular level, fibroblasts, macrophages, and neutrophils engage in a parallel strategic game in which repair reflects cooperative activity, and protease- or oxidant-producing phenotypes are indicative of defection. These parallel games are coupled through bidirectional payoff modulation, generating a dynamical system with bistability, tipping points, and runaway positive feedback. As the fraction of intact crosslinks falls below a critical percolation threshold, global network connectivity collapses and lung function drops precipitously. This framework explains the characteristic features of pulmonary emphysema, including spatial heterogeneity, abrupt acceleration, and irreversibility as emergent properties of coupled cooperation–defection dynamics, and identifies new leverage points for stabilizing cooperation and preventing catastrophic network failure in early disease. In support of this hypothesis, we present previously published studies from our laboratory involving measurements of elastin-specific desmosine crosslinks in human postmortem emphysematous lungs showing a marked increase in tissue crosslink density at the early stage of the disease, and accelerating loss of these crosslinks as airspace enlargement progresses, consistent with initial cooperation followed by defection. This conceptual framework is then applied to the poorly understood lung disease, Combined Pulmonary Fibrosis and Emphysema, to provide a potential mechanism for its pathogenesis. Full article

Unmanned aerial vehicles (UAVs) are experiencing rapid growth across diverse sectors, creating an increasing demand for lightweight, high-performance and environmentally sustainable materials. Conventional drone materials offer excellent mechanical properties but pose environmental concerns due to their high carbon footprint, energy-intensive production and limited biodegradability. Kenaf fibre, a renewable natural fibre, presents a promising alternative owing to its low density, high specific strength, cost-effectiveness and eco-friendly characteristics. This review and research proposal explores the current and potential applications of kenaf-based materials in drone manufacturing, including kenaf fibre-reinforced biocomposites, pressed paper, composite pellets and 3D printing filaments for structural, functional and electrical housing components. Kenaf-based materials have demonstrated mechanical strengths approaching 300 MPa, dielectric constants of approximately 2.5 and electrical breakdown strengths exceeding 150 kV/mm, highlighting their potential for lightweight UAV structures and electronic insulation applications. The proposed research focuses on optimising kenaf fibre treatment, fibre–matrix compatibility, hybrid reinforcement strategies and additive manufacturing parameters to develop lightweight, durable and multifunctional kenaf-based UAV components. The framework aims to establish a systematic pathway for the development and validation of kenaf-based materials for next-generation sustainable UAVs. Full article

Copper and its alloys are extensively employed in a broad range of industrial applications owing to their outstanding mechanical, electrical, and thermal properties. However, their susceptibility to corrosion in aggressive environments remains a major challenge, making corrosion inhibitors one of the most practical and cost-effective strategies for extending their service life. Nevertheless, conventional synthetic inhibitors are often limited by their high cost and adverse environmental and health impacts resulting from their toxicity. In this context, the present work provides a comprehensive experimental and theoretical assessment of the corrosion inhibition performance of Furosemide as an environmentally friendly inhibitor for copper in 3.5 wt.% NaCl solution. The corrosion inhibition performance was evaluated experimentally through gravimetric measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS), while the adsorption behavior of Furosemide was investigated using density functional theory (DFT) calculations. The results demonstrated that expired Furosemide effectively reduced the corrosion rate of copper, with the inhibition efficiency increasing as the inhibitor concentration increased and decreased with increasing temperature. A maximum inhibition efficiency of 90% was achieved at an inhibitor concentration of 400 ppm. The calculated Gibbs free energy of adsorption indicated that Furosemide adsorbs onto the copper surface through a mixed physisorption–chemisorption mechanism, following the Langmuir adsorption isotherm. Potentiodynamic polarization measurements further revealed that Furosemide predominantly suppresses the anodic dissolution reaction, indicating that it behaves as an anodic-type corrosion inhibitor. In addition, the presence of Furosemide significantly decreased the passive current density and shifted the breakdown potential toward more positive values, demonstrating an enhancement in the stability and protective character of the passive film. Electrochemical impedance spectroscopy showed that the corrosion process was governed by diffusion-controlled kinetics in the uninhibited solution, whereas the addition of Furosemide changed the corrosion mechanism to a charge-transfer-controlled process. Density functional theory (DFT) calculations provided additional insight into the inhibition mechanism of Furosemide. The calculated E_HOMO) and E_LUMO values indicate that the molecule can both donate and accept electrons, reflecting its nucleophilic and electrophilic character and its strong affinity for adsorption on the copper surface. Furthermore, the relatively small energy gap (4.631 eV) suggests high molecular reactivity and facilitates electronic interactions with the metal surface. The estimated fraction of electrons transferred further supports the electron-donating ability of Furosemide during the adsorption process. Differences between the Fukui functions and the molecular electrostatic potential (MEP) maps are attributed to the distinct chemical information provided by each descriptor. Whereas the Fukui functions identify the most reactive atomic sites involved in soft donor–acceptor interactions, the MEP maps describe the molecular charge distribution governing electrostatic (hard–hard) interactions. Full article

Synthetic fractional Brownian motion (FBM) images serve as standard data for assessing fractal dimension (FD) estimation techniques. The synthesis pipeline transforms continuous FBM matrices into 8-bit grayscale images using linear mapping and quantization, a process often regarded as benign and rarely documented. If this procedure distorts FD estimations, algorithm comparisons based on such benchmarks merge performance with preprocessing errors. We demonstrate that grayscale conversion induces systematic distortion in FD estimation. Identical matrices were initially processed using three linear mapping strategies with varying emphases (direct, 3σ statistical, external-coefficient) and subsequently assessed with four FD algorithms (two DBC variants, Higuchi, PSD). The results demonstrate that linear mapping significantly alters FD estimates. In particular, the FD regression slope of the PSD approach notably decreased from 0.9955 (direct mapping) to 0.6400 (external-coefficient mapping), whereas Higuchi displayed negligible sensitivity. The near-perfect log-log linearity ruled out scaling breakdown. The mapping strategies produce distinct grayscale statistical properties that amplify quantization residuals. We present the relative residual to measure this amplification. The relative residual correlates strongly with FD deviations for DBC and PSD methods (r up to 0.97), while showing limited association with the Higuchi estimator. These results violate the assumption of benchmark neutrality in FBM-based FD assessment. FD benchmarking studies should, therefore, report preprocessing strategies and minimize relative residuals to ensure algorithmic comparability. Full article

As a widely used encapsulant for power electronic devices, silicone gel is continuously exposed to high voltage and high temperature during service, which seriously impairs the reliability and service lifetime of power modules. This work investigates the electrothermal coupling failure mechanism of conventional silicone gel under high-voltage and high-temperature environments; the influences of different pulse electric field edge times and aging stages on various properties of the material are investigated, including electrical treeing characteristics, breakdown field strength, amplitude of charge-excited molecular vibration, leakage current, and cone penetration. It is revealed that the failure mechanism of silicone gel is attributed to the synergistic effect between dynamic charge damage induced by the pulse edge electric field and the degradation of the solid–liquid two-phase structure at high temperatures. This research provides theoretical support and experimental basis for material composition modification, structural optimization, and improving the encapsulation life of power electronic devices. Full article

Silicone gel (SG) is an important soft encapsulation dielectric for high-voltage power modules, yet its limited insulation performance under high electric fields and elevated temperatures restricts its practical application. Herein, an ultralow loading of the organic molecular semiconductor anthrone (ET) was introduced into silicone gel to simultaneously improve dielectric properties and thermal stability. SG-ET_0.5 exhibited the best overall performance, with a breakdown strength of 29.14 kV/mm at 25 °C, 19.57% higher than that of pristine SG, and retained 22.86 kV/mm at 150 °C with only a 21.56% reduction. The relative permittivity increased to 3.16 and 2.85 at 25 °C and 200 °C, respectively. The partial discharge inception voltage increased from 3.1 to 4.8 kV, while both discharge frequency and amplitude were markedly reduced. Moreover, SG-ET_0.5 showed an increased 5% weight-loss temperature of 370 °C, together with slightly increased thermal conductivity and a reduced coefficient of thermal expansion. Mechanistic analysis suggests that the low-lying LUMO level and molecular characteristics of ET may contribute to the increased deep-trap density and enhanced electron-capturing tendency of the composites, thereby helping to suppress electron avalanche development and partial discharge. This work offers a molecular-level strategy for improving the electrical insulation performance of silicone gel dielectrics for high-voltage power modules. Full article

Rosin- and castor-oil-derived resins provide a renewable platform for rapidly curable protective coatings, but the effects of formulation and curing route remain insufficiently resolved. Four composite formulations containing modified rosin glycerol ester (MRGE) and modified castor oil anhydride (MCOA) were cured thermally using ultraviolet irradiation or electron beam (EB) irradiation. Surface C=C conversion, thermal behavior, morphology, mechanical properties, neutral salt spray resistance, electrochemical barrier performance, and AC dielectric breakdown strength were evaluated. Among the formulations tested, F2 (MRGE/MCOA = 3:1) showed the best overall property balance under each curing route. For F2, EB curing produced a surface C=C conversion of 92 ± 2%, a glass transition temperature of 88 ± 1 °C, an 800 °C residue of 12.5 ± 0.3%, and an atomic force microscope (AFM) roughness Ra of 5.8 ± 0.5 nm. F2-EB exhibited 9H pencil hardness, 5B adhesion, an impact resistance of 55 ± 2 cm·kg, and a flexibility value of 1.0 ± 0.1 mm. After 500 h of neutral salt spray, both F2-EB and F2-UV achieved a protection rating of 10 with no measurable corrosion creep at the scribe; time-resolved photographs at 100, 300, and 500 h confirmed that F2-EB showed the least visible damage evolution among the three curing routes. After 1 day of immersion in 3.5 wt% NaCl, F2-EB exhibited the largest low-frequency impedance and the lowest fitted corrosion current density among the EB-cured formulations, indicating the strongest short-term electrolyte barrier behavior. The AC dielectric breakdown strength of F2-EB reached 21.5 ± 0.3 kV mm⁻¹. The combined results are consistent with more extensive EB-induced network formation, although direct measurements of through-thickness conversion and crosslink density are still required. These findings demonstrate the potential of EB curing for rapidly preparing rosin/castor-oil-derived protective coatings for electrical insulation applications. Full article

This paper is a first step toward providing answers to the question of whether fractal pattern formation gives rise to power-law (fractional) kinetics and how such kinetics relate to geometric properties such as fractal dimension. The study focuses on Lichtenberg figures produced by high-voltage discharges on wood, a heterogeneous dielectric medium with anisotropic conductivity and variable moisture content. During breakdown, the discharge propagates through branching streamers and carbonization fronts, exhibiting scale-free growth, long-tailed waiting times, and memory effects. The associated current signals are analyzed using the theory of fractal elements developed by Nigmatullin and Chen. This framework allows complex self-similar waveforms to be decomposed into elementary fractal modes characterized by power-law exponents and amplitudes. The results show that the electrical response is governed by fractional dynamics encoded in these modes. However, no direct one-to-one relationship is found between the fractal dimension of the discharge patterns and the kinetic power-law exponents. This decoupling is attributed to the influence of the heterogeneous medium and the percolation pathways through which the discharge propagates. Full article

China hosts abundant coal-rock gas (CRG) resources, which have become a critical unconventional natural gas contributor to national reserve expansion and production increment. Supercritical carbon dioxide (ScCO₂) fracturing is recognized as a green and efficient stimulation technology, exhibiting great potential for high-efficiency CRG exploitation. To clarify the effects and intrinsic mechanisms of ScCO₂ treatment on coal fracture initiation, propagation, and CRG recovery enhancement, true triaxial fracturing and CO₂-CH₄ displacement experiments were performed in combination with multiple microscopic characterization methods, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Scanning electron microscopy (SEM). The multi-scale experimental investigation systematically revealed the fracture development mechanism, permeability variation characteristics, and microstructural evolution of coal reservoirs under ScCO₂ interactions. The results indicate that ScCO₂ fracturing significantly lowers the coal fracture initiation threshold compared with conventional hydraulic fracturing, with the breakdown pressure reduced by 26.2% and the initiation time shortened by 37.5%. Such advantages facilitate coal fracture activation and the development of complex fracture networks. Long-term ScCO₂ soaking induces the dissolution of inorganic minerals (e.g., calcite, plagioclase, and clay minerals) and the extraction of inherent organic matter within coal matrices. The coupled hydro-chemical reactions reconstruct the coal pore structure, enlarge pore throats, and improve reservoir permeability, achieving a maximum permeability enhancement of approximately 1.6 times. Meanwhile, ScCO₂ displacement yields a prominent CRG recovery performance, with an ultimate gas recovery factor up to 93.85%. The CRG enhancement mechanism of ScCO₂ fracturing is comprehensively attributed to three core coupled effects. First, ScCO₂ dynamic fracturing generates intricate fracture networks, which greatly optimize reservoir seepage channels and flow space. Second, the ScCO₂–formation water–coal interaction modifies coal physical properties via mineral dissolution and organic matter extraction, thereby improving reservoir permeability. Third, the preferential adsorption of CO₂ over CH₄ triggers effective competitive adsorption and gas displacement, further promoting adsorbed methane desorption and elevating CRG recovery efficiency. This study provides a solid theoretical foundation for the field application of ScCO₂ fracturing technology and offers valuable insights into the green, efficient, and sustainable development of deep coal-rock gas resources. Full article

The long-term reliability of XLPE submarine cable insulation is influenced by progressive thermal degradation during operation and subsequent seawater ingress caused by external damage. Although thermal aging and seawater exposure have been widely investigated individually, the influence of the prior thermal-aging state on the subsequent seawater-induced degradation behavior of XLPE remains insufficiently understood. In this study, XLPE insulation specimens prepared from the same commercial compound used for 500 kV submarine cables were subjected to sequential accelerated aging consisting of controlled thermal pre-aging followed by simulated seawater exposure. Broadband dielectric spectroscopy, AC breakdown testing with two-parameter Weibull analysis, scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) were employed to investigate the evolution of electrical properties, surface morphology, and molecular structure. The results demonstrate that seawater-induced electrical deterioration strongly depends on the initial thermal-aging state of XLPE. Increasing thermal pre-aging duration resulted in progressively higher relative permittivity and dielectric loss, together with reduced characteristic breakdown strength after subsequent seawater exposure. Under the most severe condition of 1440 h thermal pre-aging followed by 672 h seawater exposure, the power–frequency relative permittivity increased by 32.1%, while the characteristic breakdown strength decreased by more than one-third compared with the initial state. SEM observations revealed that thermally pre-aged specimens developed accelerated surface damage during seawater exposure, including pores, cracks, corrosion pits, and honeycomb-like structures. FTIR analysis further indicated molecular-chain degradation and increased hydroxyl-related species during sequential aging. These results suggest that thermal-aging-induced molecular oxidation, polar-group formation, and microstructural defects enhance water and ion penetration pathways, thereby increasing the susceptibility of XLPE insulation to subsequent seawater-induced degradation. This study provides material-level experimental evidence for understanding sequential aging processes in submarine cable insulation and highlights the importance of considering historical thermal damage in future condition assessment and lifetime evaluation models. Since accelerated laboratory conditions were adopted, the results should be interpreted as comparative degradation characteristics rather than direct predictions of field-service lifetime. Full article

Hydraulic fracturing enhances productivity in low-permeability reservoirs. The introduction of nanomodified gels for hydraulic fracturing has raised the need to revise traditional approaches to their breakdown, as nanoparticles significantly change the kinetics and mechanisms of degradation. In this paper, for the first time, a systematic experimental study of the effects of chemical breakers on the rheological properties of nanomodified guar gels has been conducted. Two commercial oxidative breakers were used, which generate free radicals and cleave the guar polymer backbone, reducing viscosity. The effect of breaker concentration (0–1.82 wt%), as well as the concentration, size, and morphology of nanoparticles on gel breaking, has been studied. Guar gum was used as a gelling agent, and spherical SiO₂ and Al₂O₃ nanoparticles, as well as aluminum oxide nanofibers (ANFs), were used as additives. An increase in breaker concentration accelerates gel breaking. For instance, at 0.68 wt% breaker, complete degradation occurs in about 3 h, whereas at 1.82 wt% it takes only about half an hour, with the viscosity dropping to 30 mPa·s. While nano-additives can either slow down or accelerate degradation depending on their type, size, and concentration, the addition of 0.4 wt% ANFs prolong the degradation time to more than two hours even at the highest breaker concentration. These effects are attributed to the competition between polymer chain scission by free radicals and the formation of physical crosslinks mediated by nanoparticles. The results demonstrate the possibility of purposefully controlling the kinetics of breaking of nanomodified gels for hydraulic fracturing by optimally selecting the breaker composition and nano-additive parameters. Full article