Search Results (8,369)

Woody raw materials of wood-based panels like fiberboard and particleboard are one of the primary sources of product odor and one of the indicators affecting the comprehensive health risk assessment of wood-based panel products. This study employed Gas Chromatography-Mass Spectrometry-Olfactometry (GC-MS-O) to investigate the odorant composition and odor characteristics, including Total Odor Concentration (TOC), odor intensity (OI), odor activity value (OAV), and risk value (RV), of 22 wood species commonly used in fiberboard and particleboard production in China. This research identified the major odor-active compounds in wood and provided recommendations for selecting wood raw materials suitable for low-odor fiberboards and particleboards produced by integrating RV and toxicity classification data. The results showed that the main compound types influencing wood odor in 22 wood species were predominantly terpenes, aldehydes, and alcohols. Woods of Cinnamomum, Machilus, and Pinus contained a higher number of dominant odor compounds (OAV > 1 and OI ≥ 3). Wood with stronger odor intensity included Cinnamomum, Pinus, Machilus, Bischofia, and Saurauia. The total RV of Cinnamomum, Pinus, Machilus, Cunninghamia, and Bombax wood exceeded one, necessitating special attention when used as raw materials for wood-based panels. Camphor in Cinnamomum and Machilus wood was the most concentrated odorant, followed by 3-Carene in Pinus wood. Odorants with high OAV included Longifolene, δ-Cadinene, Terpinen-4-ol, 2-Nonenal, γ-Terpinene, d-Limonene, 3-methyl-Butanal, Octanal, α-Pinene, Hexanal, D-Camphor, and trans-Calamenene. Odorants with high RV included terpenes, alcohols, aldehydes, and ketones, such as Camphor, 3-Carene, Eucalyptol, α-Terpineol, β-Pinene, α-Santalene, δ-Cadinene, Safrole, Longifolene, and d-Limonene. Focusing on the reduction and control of these odor-active compounds represents a primary approach to mitigating odors in fiberboard and particleboard products. However, addressing health risks associated with product odors requires additional attention to four specific substances: Safrole, Camphor, Eucalyptol, and α-Terpineol. Although the total RV for the five wood species exceeds one, this does not necessarily mean the final wood-based panel product’s RV exceeds one, as it also depends on the influence of the production process. Therefore, further research should be conducted to investigate the effects of various process parameters in wood-based panel production on the odor compounds present in the final panels. From a comprehensive perspective, considering the overall odor characteristics of wood volatiles, all 18 wood species (Salix, Populus, Rhaphiolepis, Ligustrum, Prunus, Fagus, Pterocarya, Firmiana, Celtis, Cunninghamia, Bombax, Bischofia, Ficus, Saurauia, Eucalyptus, Aleurites, Melia, Bridelia) are suitable for the production of low-odor fiberboards and particleboards. Full article

Voluntary Isocapnic Hyperpnea (VIH), a respiratory muscle training method, is assumed to stabilize blood CO₂ levels during increased ventilation, potentially supporting cellular homeostasis. The study aimed to empirically validate the concept and determine whether VIH effectively preserves key blood gas indices across different ambient oxygen levels in various populations. Two cross-sectional experiments (longitudinal in normoxia in highly trained athletes, n = 9 and single session in severe hypoxia of 4200 m above sea level in healthy and active participants, n = 18) were performed. Paired Bayesian t-tests and repeated measures analysis of variance were used to compare values of hydrogen ion concentration (pH), bicarbonate ion (HCO₃⁻), partial pressure of oxygen (pO₂), and partial pressure of carbon dioxide (pCO₂) before and after VIH sessions. Except for pO₂ (BF₁₀ = 1.596 to 7.986), there were no meaningful differences in the analyzed variables before and after VIH in normoxia (BF₁₀ = 0.322 to 0.490). These findings remained consistent for different familiarization and training statuses of participants, as well as sessions’ length and intensity. The likelihood of differences in pH, pO₂, and pCO₂ in hypoxia was supported by BF₁₀ values between 1.349 and 6.304. No between-sex differences were observed. Our observations highlight the physiological robustness of VIH in maintaining blood gas and pH equilibrium in normoxia, with potential implications for supporting cellular acid–base homeostasis and mitochondrial function. In severe hypoxia, VIH was associated with changes in multiple analyzed variables, suggesting the need for caution, along with increased requirements for protocol individualization and monitoring. Full article

A bioresorbable cannulated bone screw was developed using PLA/PCL-based composites reinforced with hydroxyapatite (HA) and titanium dioxide (TiO₂), two additives previously reported to enhance mechanical compliance, biocompatibility, and molding feasibility in biodegradable polymer systems. The design incorporated a crest-trimmed thread and a strategically positioned gate in the thin-wall zone opposite the hexagonal socket to preserve torque-transmitting geometry during micromolding. To investigate shrinkage behavior, a Taguchi orthogonal array was employed to systematically vary micromolding parameters, generating a structured dataset for training a back-propagation neural network (BPNN). Analysis of variance (ANOVA) identified melt temperature as the most influential factor affecting shrinkage quality, defined by a combination of shrinkage rate and dimensional variation. A hybrid AI framework integrating the BPNN with genetic algorithms and particle swarm optimization (GA–PSO) was applied to predict the optimal shrinkage conditions. This is the first use of BPNN–GA–PSO for cannulated bone screw molding, with the shrinkage rate as a targeted output. The AI-predicted solution, interpolated within the Taguchi design space, achieved improved shrinkage quality over all nine experimental groups. Beyond the specific PLA/PCL-based systems studied, the modeling framework—which combines geometry-specific gate design and normalized shrinkage prediction—offers broader applicability to other bioresorbable polymers and hollow implant geometries requiring high-dimensional fidelity. This study integrates composite formulation, geometric design, and data-driven modeling to advance the precision micromolding of biodegradable orthopedic devices. Full article

The ocean harbors vast potential for oil and gas resources, positioning offshore drilling as a critical approach for future energy exploration. However, high-temperature and high-pressure offshore reservoirs present formidable challenges, as conventional water-based drilling fluids are prone to thermal degradation and rheological instability, leading to wellbore collapse and stuck-pipe incidents. Offshore oil-based drilling fluids (OBDFs), typically water-in-oil emulsions, offer advantages in wellbore stability, lubricity, and contamination resistance, yet their stability under extreme high-temperature conditions remains limited. This study reveals the enhancement of offshore OBDFs performance in harsh conditions by employing nano-SiO₂ to synergistically improve emulsion film stability and non-Newtonian rheological behavior while systematically elucidating the underlying mechanisms. Nano-SiO₂ forms a composite film with emulsifiers, reducing droplet size, enhancing mechanical strength, and increasing thermal stability. Optimal stability was observed at an oil-to-water ratio of 7:3 with 2.5% nano-SiO₂ dispersion and 4.0% emulsifier. Rheological analyses revealed that nano-silica enhances electrostatic repulsion, reduces plastic viscosity, establishes a network structure that increases yield stress, and promotes pronounced shear-thinning behavior. Macroscopic evaluations, including fluid loss, rheological performance, and electrical stability, further confirmed the improved high-temperature stability of offshore OBDFs with nano-SiO₂ at reduced emulsifier concentrations. These findings provide a theoretical basis for optimizing offshore OBDFs formulations and their field performance, offering breakthrough technological support for safe and efficient drilling in ultra-high-temperature offshore reservoirs. Full article

(Y_xGd_3−x)(Al_yGa_5−y)O₁₂:Ce and (Lu_xGd_3−x)(Al_yGa_5−y)O₁₂:Ce ceramics were synthesized for the first time by direct exposure of a powerful electron flux to a mixture of the corresponding oxide components. Five-component ceramics were obtained from oxide powders of Y₂O₃, Lu₂O₃, Gd₂O₃, Al₂O₃, Ga₂O₃, and Ce₂O₃ in less than 1 s, without the use of any additional reagents or process stimulants. The average productivity of the synthesis process was approximately 5 g/s. The reaction yield, defined as the mass ratio of the synthesized ceramic to the initial mixture, ranged from 94% to 99%. The synthesized ceramics exhibit photoluminescence when excited by radiation in the 340–450 nm spectral range. The position of the luminescence bands depends on the specific composition, with the emission maxima located within the 525–560 nm range. It is suggested that under high radiation power density, the element exchange rate between the particles of the initial materials is governed by the formation of an ion–electron plasma. Full article

The adsorption of gas reactant molecules (H₂, CO, etc.) to the surface of hematite is the premise of chemical reaction. In order to further promote the basic research on the reaction mechanism of hematite reduction by a H₂-CO gas mixture, the adsorption behavior of H₂ (or CO) under the conditions of pre-adsorbed H₂O (or CO₂) was systematically studied by the density functional theory (DFT) combined with reduction experiments. The results indicate that the gas molecules (H₂, CO, H₂O and CO₂) adsorbed on the Fe atom of the Fe₂O₃ (001) surface rather than the O atom, and the adsorption energy of the Fe₂O₃-CO adsorption system was relatively minimum (−1.317 eV), indicating that the Fe₂O₃-CO adsorption system was more stable. In addition, the adsorption energy of the H₂ molecule adsorbed to the Fe₂O₃-H₂O adsorption system was −0.132 eV, which was smaller than that of the H₂ molecule directly adsorbed to Fe₂O₃ (−0.013 eV), indicating that the H₂O molecule pre-adsorption was beneficial to the H₂ molecule adsorption. Compared with the H₂O molecule, the CO₂ molecule had relatively less influence on the adsorption and subsequent behavior of CO with Fe₂O₃. From the experiment analysis results, on the whole, CO₂ had a greater impact on the gas diffusion, while H₂O had a greater impact on the interfacial chemical reaction (gas adsorption), which was consistent with the DFT calculation results. Full article

Gallic acid (GA), a polyphenol extensively used in the food, wine, and pharmaceutical industries, is known for its inhibitory effects on soil microbial activity. Photocatalytic degradation offers an environmentally friendly solution for GA removal from water. In this work, graphitic carbon nitride (g-C₃N₄) photocatalysts were synthesized by two methods: thermal exfoliation (CN-E) and supramolecular assembly via hydrothermal processing (HCN-II). Structural analyses by XRD, FTIR, and XPS confirmed the formation of the g-C₃N₄ framework, while SEM revealed that CN-E consisted of folded and curled nanosheets, whereas HCN-II displayed a polyhedral–nanosheet hybrid architecture with internal channels. Both materials achieved approximately 80% GA degradation within 180 min under visible-light irradiation, yet HCN-II exhibited a superior apparent rate constant (k = 0.01156 min⁻¹) compared with CN-E. Radical trapping experiments demonstrated that O₂•⁻ and h⁺ were the primary reactive oxygen species involved, with OH• making a minor contribution. The enhanced performance of HCN-II is attributed to its higher surface area, improved light harvesting, and efficient charge separation derived from supramolecular assembly. These findings highlight the potential of engineered g-C₃N₄ nanostructures as efficient, metal-free photocatalysts for the degradation of recalcitrant organic pollutants in water treatment applications. Full article

The emissions from biomass combustion systems have recently been the subject of increased attention. In addition to elevated concentrations of particulate matter and hydrocarbons (HCs) in the flue gas, significant levels of NO_x emissions occur depending on the used fuel, such as biogenic residues. In response to legal requirements, owners of medium-sized plants (≈100 kW) are now also forced to minimize these emissions by means of selective catalytic reduction systems (SCR). The implementation of a selective sensor is essential for the efficient dosing of the reducing agent, which is converted to ammonia (NH₃) in the flue gas. Preliminary laboratory investigations on a capacitive NH₃ sensor based on a zeolite functional film have demonstrated a high sensitivity to ammonia with minimal cross-influences from H₂O and NO_x. Further investigations concern the application of this sensor in the real flue gas of an ordinary wood-burning stove and of combustion plants for biogenic residues with an ammonia dosage. The findings demonstrate a high degree of agreement between the NH₃ concentration measured by the sensor and an FTIR spectrometer. Furthermore, the investigation of the long-term stability of the sensor and the poisoning effects of SO₂ and HCl are of particular relevance to the laboratory measurements in this study, which show promising results. Full article

Chronic respiratory diseases claim nearly four million lives annually, making them the third leading cause of death worldwide. Extracorporeal membrane oxygenation (ECMO) is often the last line of support for patients with severe lung failure. Still, its performance is limited by an incomplete understanding of gas exchange in hollow fiber membrane (HFM) oxygenators. Computational fluid dynamics (CFD) has become a robust oxygenator design and optimization tool. However, most models oversimplify O₂ and CO₂ transport by ignoring their physiological coupling, instead relying on fixed saturation curves or constant-content assumptions. For the first time, this study introduces a novel physiologically informed CFD model that integrates the Bohr and Haldane effects to capture the coupled transport of oxygen and carbon dioxide as functions of local pH, temperature, and gas partial pressures. The model is validated against in vitro experimental data from the literature and assessed against established CFD models. The proposed CFD model achieved excellent agreement with experiments across blood flow rates (100–500 $\mathrm{mL}/\min$ ), with relative errors below 5% for oxygen and 10–15% for carbon dioxide transfer. These results surpassed the accuracy of all existing CFD approaches, demonstrating that a carefully formulated single-phase model combined with physiologically informed diffusivities can outperform more complex multiphase simulations. This work provides a computationally efficient and physiologically realistic framework for oxygenator optimization, potentially accelerating device development, reducing reliance on costly in vitro testing, and enabling patient-specific simulations. Full article

Silver tarnish is a major issue in many heritage institutions. Applying lacquer is frequently used when preventive conservation approaches are limited. The service lifetime of the lacquer has a strong impact on resources and sustainability. Little systematic work has been published on this. This work explores three thresholds on lifetime—visual, reversibility, and loss of protection. It uses thermodynamic modelling to predict lacquer lifetime from aging at four temperatures. Samples on sterling silver with Frigilene lacquer were used and aging was assessed with a Bruker Alpha FTIR using external reflectance. The FTIR ratio of produced carbonyl peak to nitrate peaks was used to quantify the aging. The commonly used C-O-C peak was found to suffer from dispersion in a high proportion of samples, so could not be used in this study. The results were compared with measurements of lacquer on silver objects displayed in showcases and from store (with almost no light exposure). Spectra were obtained with the Bruker Alpha or an Inspect infra-red microscope. Autocatalytic effects through concentration of emitted nitrogen oxide gases have also been explored using diffusion tubes and gas ingress analysis. No significant concentration was observed. The thresholds were clearly established, and the model produced similar results to the natural aging studied. Full article

Abalone is among the most highly prized seafoods, valued for its delicate flavor and texture. As abalone aquaculture continues to expand, addressing its environmental impacts has become increasingly important. Although aquaculture is recognized as a contributor to greenhouse gas (GHG) emissions, the specific mechanisms and pathways of GHG emissions—particularly in abalone farming—remain poorly understood. To clarify the patterns and drivers of GHG emissions in abalone (Haliotis discus) culture systems, this study was conducted in three aquaculture ponds located in Gongliao District, New Taipei City, Taiwan. We measured CO₂, CH₄, and N₂O fluxes along with key environmental parameters to assess variation across sampling locations, times, and seasons. The results showed that sampling time had no significant effect on GHG flux variations, whereas seasonal changes influenced all three gases, and sampling location significantly affected N₂O flux only. During the culture period, average fluxes were 2.19 ± 10.83 mmol m⁻² day⁻¹ for CO₂, 2.11 ± 2.81 µmol m⁻² day⁻¹ for CH₄, and 1.65 ± 2.73 µmol m⁻² day⁻¹ for N₂O, indicating that the abalone ponds served as net sources of these GHGs. When converted to CO₂-equivalents (CO₂-eq), the total average CO₂-eq flux from the ponds was 0.02 ± 0.09 mg CO₂-eq m⁻² day⁻¹, calculated using global warming potential (GWP₂₀ and GWP₁₀₀) metrics. This study provides the first comprehensive assessment of GHG emissions in abalone pond systems and offers valuable insights into their emission dynamics. The findings contribute to the scientific basis needed to improve aquaculture GHG inventories. Full article

Gallium oxide (Ga₂O₃)-based memristors are gaining traction as promising candidates for next-generation electronic devices toward in-memory computing, leveraging the unique properties of Ga₂O₃, such as its wide bandgap, high thermodynamic stability, and chemical stability. This review explores the evolution of memristor theory for Ga₂O₃-based materials, emphasising capacitive memristors and their ability to integrate resistive and capacitive switching mechanisms for multifunctional performance. We discussed the state-of-the-art fabrication methods, material engineering strategies, and the current challenges of Ga₂O₃-based memristors. The review also highlights the applications of these memristors in memory technologies, neuromorphic computing, and sensors, showcasing their potential to revolutionise emerging electronics. Special focus has been placed on the use of Ga₂O₃ in capacitive memristors, where their properties enable improved switching speed, endurance, and stability. In this paper we provide a comprehensive overview of the advancements in Ga₂O₃-based memristors and outline pathways for future research in this rapidly evolving field. Full article

In the race for industrialization and urbanization, the concentration of greenhouse gases like CO₂ and CH₄ is growing rapidly and ultimately resulting in global warming. An Ni-based catalyst over MgO support (Ni/MgO) offers a catalytic method for the conversion of these gases into hydrogen and carbon monoxide through the dry reforming of methane (DRM) reaction. In the current research work, 1–4 wt% strontium is investigated as a cheap promoter over a 5Ni/MgO catalyst to modify the reducibility and basicity for the goal of excelling the H₂ yield and H₂/CO ratio through the DRM reaction. The fine catalytic activities’ correlations with characterization results (like X-ray diffraction, surface area porosity, photoelectron–Raman–infrared spectroscopy, and temperature-programmed reduction/desorption (TPR/TPD)) are established. The 5Ni/MgO catalyst with a 3 wt.% Sr loading attained the highest concentration of stable active sites and the maximum population of very strong basic sites. 5Ni3Sr/MgO surpassed 53% H₂ yield (H₂/CO ~0.8) at 700 °C and 85% H₂ yield (H₂/CO ratio ~0.9) at 800 °C. These outcomes demonstrate the catalyst’s effectiveness and affordability. Higher Sr loading (>3 wt%) resulted in a weaker metal–support contact, the production of free NiO, and a lower level of catalytic activity for the DRM reaction. The practical and cheap 5Ni3Sr/MgO catalyst is scalable in industries to achieve hydrogen energy goals while mitigating greenhouse gas concentrations. Full article

Ultra-wide bandgap β-Ga₂O₃ is a promising low-cost alternative to conventional direct X-ray detector materials that are limited by fabrication complexity, instability, or slow temporal response. Here, we comparatively investigate β-Ga₂O₃ thin films grown on c-sapphire by low-pressure chemical vapor deposition (LPCVD) and plasma-enhanced CVD (PECVD), establishing a quantitative linkage between growth kinetics, microstructure, defect landscape, and X-ray detection figures of merit. The LPCVD-grown film (thickness ≈ 0.289 μm) exhibits layered coalesced grains, a narrower rocking curve (FWHM = 1.840°), and deep-level oxygen-vacancy-assisted high photoconductive gain, yielding a high sensitivity of 1.02 × 10⁵ μC Gy_air⁻¹ cm⁻² at 20 V and a thickness-normalized sensitivity of 3.539 × 10⁵ μCGy_air⁻¹ cm⁻² μm⁻¹. In contrast, the PECVD-grown film (≈1.57 μm) shows dense columnar growth, higher O/Ga stoichiometric proximity, and shallow-trap dominance, enabling a lower dark current, superior dose detection limit (30.13 vs. 57.07 nGy_air s⁻¹), faster recovery, and monotonic SNR improvement with bias. XPS and dual exponential transient analysis corroborate a deep-trap persistent photoconductivity mechanism in LPCVD versus moderated shallow trapping in PECVD. The resulting high-gain vs. low-noise complementary paradigm clarifies defect–gain trade spaces and provides a route to engineer β-Ga₂O₃ thin-film X-ray detectors that simultaneously target high sensitivity, low dose limit, and temporal stability through trap and electric field management. Full article

Tourist flow prediction plays a crucial role in enhancing the efficiency of scenic area management, optimizing resource allocation, and promoting the sustainable development of the tourism industry. To improve the accuracy and real-time performance of tourist flow prediction, we propose a BP model based on a hybrid genetic algorithm (GA) and ant colony optimization algorithm (ACO), called the GA-ACO-BP model. First, we comprehensively considered multiple key factors related to tourist flow, including historical tourist flow data (such as tourist flow from yesterday, the previous day, and the same period last year), holiday types, climate comfort, and search popularity index on online map platforms. Second, to address the tendency of the BP model to get easily stuck in local optima, we introduce the GA, which has excellent global search capabilities. Finally, to further improve local convergence speed, we further introduce the ACO algorithm. The experimental results based on tourist flow data from the Elephant Trunk Hill Scenic Area in Guilin indicate that the GA-AC*O-BP model achieves optimal values for key tourist flow prediction metrics such as MAPE, RMSE, MAE, and R², compared to commonly used prediction models. These values are 4.09%, 426.34, 258.80, and 0.98795, respectively. Compared to the initial BP neural network, the improved GA-ACO-BP model reduced error metrics such as MAPE, RMSE, and MAE by 1.12%, 244.04, and 122.91, respectively, and increased the R² metric by 1.85%. Full article