Search Results (115)

Microplastics are pervasive environmental pollutants that pose risks to human health through ingestion and inhalation. This review synthesizes current practices to reduce exposure and toxicity by examining major exposure routes and dietary interventions. More than 130 papers were analyzed to achieve this aim. The findings show that microplastics contaminate a wide range of food products, with particular concern over seafood, drinking water, plastic-packaged foods, paper cups, and tea filter bags. Inhalation exposure is mainly linked to indoor air quality and smoking, while dermal contact poses minimal risk, though the release of additives from plastics onto the skin remains an area of concern. Recommended strategies to reduce dietary exposure include consuming only muscle parts of seafood, moderating intake of high-risk items like anchovies and mollusks, limiting canned seafood liquids, and purging mussels in clean water before consumption. Avoiding plastic containers, especially for hot food or microwaving, using wooden cutting boards, paper tea bags, and opting for tap or filtered water over bottled water are also advised. To mitigate inhalation exposure, the use of air filters with HyperHEPA systems, improved ventilation, regular vacuuming, and the reduction of smoking are recommended. While antioxidant supplementation shows potential in reducing microplastic toxicity, further research is needed to confirm its effectiveness. This review provides practical, evidence-based recommendations for minimizing daily microplastic exposure. Full article

The aerospace industry is increasingly turning to composite materials due to their exceptional strength, stiffness, and beneficial physical properties. However, increased reliance on carbon fibre composites has substantial environmental implications, particularly concerning waste management. Recycling these materials is a potential solution to these sustainability issues, provided the recycled fibres retain adequate mechanical strength and durability. This study evaluates the mechanical capabilities of recycled carbon fibres in a scaled-down aircraft spar model (AMT-600 GURI), contrasting them with the capabilities of conventional spars. The primary objective is to ascertain whether recycled composites can fulfil the stringent structural requirements of aerospace applications, employing both simulation and experimental validation methods. The recycled carbon fibre composites were manufactured using hand lay-up and vacuum bagging techniques, and their properties were validated through rigorous tensile and compressive strength testing. These validated results were then used to inform a finite element model developed in HyperWorks software. Simulations revealed that the recycled spar achieved maximum stress values of 3.87 MPa under lift forces, a slight increase of +8.95% compared to the original spar, and 55.05 MPa under drag forces, a significant improvement of +36%. Aerodynamic evaluations further confirmed the structural resilience of the recycled spar, with displacement measurements of 141.4 mm for lift and 504.8 mm for drag, closely aligning with the original spar’s performance. In summary, this study demonstrates that recycled carbon fibre composites can serve as effective substitutes for traditional aerospace materials, thereby supporting sustainability initiatives without compromising performance. The outlined approach provides a reliable framework for incorporating recycled materials. Full article

With the continuous development of new aircraft, the application of low-cost composite materials technology still encounters numerous challenges and issues. The development of low-cost composite technology, while ensuring the high reliability of aircraft components, has become a common concern among aerospace composites. The research presented in this paper examines the findings related to the conformity verification process of an electric aircraft in China. This is an all-composite structural general aviation aircraft certified under CCAR Part 23. This study focuses on the quality characteristics of low-cost wet vacuum bagging composites, addressing the causes and effects of high porosity in the manufacturing process. Based on the research findings, a relationship between porosity and the strength of wet vacuum bagging composites is established. Consequently, a safe and reliable method for ensuring airworthiness conformity of low-cost composites is proposed and implemented in the aircraft type’s conformity verification. Furthermore, this paper discusses the development trends of low-cost composites for general aviation, providing valuable insights for the advancement of low-cost technologies in the future. Full article

Natural fibre-reinforced composites are becoming increasingly popular due to their affordability, sustainability, and biodegradability. These composites, made from recyclable materials, are suitable for various sustainable energy applications due to their remarkable mechanical properties and life cycle advantages. The biodegradable composite materials are a sustainable alternative for energy applications. This composite construction uses Soric XF (Lantor Composites, Veenendaal, The Netherlands) as the fibre reinforcement core material and jute fibre, an eco-friendly and sustainable substitute for glass fibre reinforcement composite materials, as the outer face sheet obtained from jute bags. The dry fibres are piled as dry loads at various fibre orientation angles, including 0°, 45°, and 90°, and this orientation will be reflected in the composite strength. Vacuum-assisted resin transfer moulding (VARTM) is a technique used to fabricate this material at room temperature. Further, this research focuses on a comparative analysis of experimental and computational results involving composite materials with jute fibre as the outer face sheet and Soric XF as the fibre reinforcement core material. The experimental investigation included tensile ASTM D638-03 and flexural ASTM D790 to evaluate the composite’s mechanical properties and structural integrity under various load conditions. Simultaneously the computational simulations were performed using the ANSYS-Mechanical 2023 R2 to replicate these conditions and predict the composite’s performance. The experimental and simulated data were analysed and compared. This study demonstrates the efficacy of using computational tools to predict the behaviour of natural fibre composites. It underscores the importance of experimental validation for enhancing the reliability of simulation models. The results from the computational study are compared with the experimental results to study the predictive nature of the NFRC material. Full article

Venerupis corrugata (pullet carpet shell) is a premium native clam species in Portugal. This species is highly perishable, typically sold live within 3 or 4 days, posing a significant risk of loss. Therefore, efforts to extend its shelf-life are relevant. The impact of the storage temperature (3, 5, 8 and 12 °C) on clams in plastic net bags and the effect of modified atmosphere packaging (MAP) were investigated. The survival percentage and microbiological and chemical parameters were evaluated, as well as sensory characteristics. The survival percentage and sensory aspects results indicate that the longest time with 95% live clams was observed at 5 °C and 8 °C, but lower temperatures (3 and 5 °C) have lower death rates after the threshold. In the MAP tests, the clams were kept closed due to confinement in plastic trays applying a vacuum, before gas flushing that drew the lid film over the clams. However, a negative effect of CO₂ was observed for clams, with lower survival when packaged in 30% CO₂. The shelf-life increased by only 1–2 days under >70% O₂ with no CO₂. These results show that this species is very sensitive, and MAP is not commercially effective for this application. Full article

In this research paper, the ±45 biaxially oriented woven flax and its hybrid flax/carbon composite laminates are manufactured by the vacuum bag technique using vinyl ester as the resin binder and the samples are characterized to evaluate their tensile, flexural and impact properties. Combining natural fibers with conventional materials typically creates a hybrid composite that shows optimal mechanical properties with partial sustainability. The flax/carbon variant exhibited superior tensile strength values of 383.88 MPa and 32.60 GPa, which are about 3.5 and 2.7 times higher than the flax composites, their flexural strengths are around 415.57 MPa and 25.02 GPa, respectively, and they have an impact resistance of 12.67 J. Full article

Nanocomposite laminates containing carbon fibers, epoxy, and multiwalled carbon nanotubes were fabricated using a vacuum bag process. Ecofriendly ionic liquid (5 wt%)-treated multiwalled carbon nanotubes (pristine and nickel-coated) were added to the epoxy independently, in amounts ranging from 1 wt% to 3 wt%, in order to tailor the mechanical, electrical, and thermal performance of manufactured carbon fiber epoxy composite laminates. These nanocomposite laminates were later characterized through flexural testing, dynamic mechanical analysis, impedance spectroscopy, thermal conductivity tests, and FTIR spectroscopy to evaluate their suitability for battery pack applications. The findings showed that both types of multiwalled carbon nanotubes exhibited multifaceted effects on the properties of bulk hybrid carbon fiber epoxy nanocomposite laminates. For instance, the flexural strength of the composites containing 3.0 wt% of ionic liquid-treated pristine multiwalled carbon nanotubes reached 802.8 MPa, the flexural modulus was 88.21 GPa, and the storage modulus was 18.2 GPa, while the loss modulus peaked at 1.76 GPa. The thermal conductivity of the composites ranged from 0.38869 W/(m · K) to 0.69772 W/(m · K), and the electrical resistance decreased significantly with the addition of MWCNTs, reaching a minimum of 29.89 Ω for CFRPIP-1.5 wt%. The structural performance of hybrid nanocomposites containing ionic liquid-treated pristine multiwalled carbon nanotubes was higher than that of the hybrid nanocomposite of ionic liquid-treated Ni-coated multiwalled carbon nanotubes, although the latter was found to possess better functional performance. Full article

In order to explore the effects of different silage inoculants on the silage quality of alfalfa (Medicago sativa L.), this study utilized six groups of experimental treatments and five kinds of additive treatments: Xinlaiwang I straw silage (group A), Xinlaiwang I alfalfa silage (group B), Zhuanglemei silage starter culture (group C), Baoshiqing (group D), Kangfuqing S lactic acid bacteria silage (group E), and another blank control group (CK group, distilled water). The effect of silage on fermentation characteristics and nutritional value of Adina alfalfa silage was studied by membership function analysis. The main study variable was inoculant strains. Alfalfa silage was packed into polyethylene plastic vacuum bags in the laboratory and sealed for 60 days. The silage was divided into six treatment groups with three replicates per group. The fermentation performance and nutrient composition of the silage were determined. The results showed that compared with the control group, adding Xinlaiwang I alfalfa silage (group B) could significantly increase the contents of crude protein (CP) and lactic acid (LA) in alfalfa silage (p < 0.05), decrease the contents of neutral detergent fiber (NDF) and acid detergent fiber (ADF), and decrease the pH and ammoniacal nitrogen/total nitrogen (AN/TN). The results showed that different inoculants could improve the silage quality of alfalfa to different extent, and Xinlaiwang I alfalfa silage had the best effect. Full article

Structural batteries, also known as “massless batteries”, integrate energy storage directly into load-bearing materials, offering a transformative alternative to traditional Li-ion batteries. Unlike conventional systems that serve only as energy storage devices, structural batteries replace passive structural components, reducing overall weight while providing mechanical reinforcement. However, achieving uniform and efficient coatings of active materials on carbon fibers remains a major challenge, limiting their scalability and electrochemical performance. This study investigates ultrasonic spray coating as a precise and scalable technique for fabricating composite cathodes in structural batteries. Using a computer-controlled ultrasonic nozzle, this method ensures uniform deposition with minimal material waste while maintaining the mechanical integrity of carbon fibers. Compared to traditional techniques such as electrophoretic deposition, vacuum bag hot plate processing, and dip-coating, ultrasonic spray coating achieved superior coating consistency and reproducibility. Electrochemical testing revealed a specific capacity of 100 mAh/g_LFP with 80% retention for more than 350 cycles at 0.5 C, demonstrating its potential as a viable coating solution. While structural batteries are not yet commercially viable, these findings represent a step toward their practical implementation. Further research and optimization will be essential in advancing this technology for next-generation aerospace and transportation applications. Full article

The increasing demand for high-performance materials in industrial applications highlights the need for composites with enhanced mechanical and tribological properties. Basalt fiber-reinforced polymers (BFRP) are promising materials due to their superior strength-to-weight ratio and environmental benefits, yet their wear resistance and tensile performance often require further optimization. This study examines how adding copper (Cu) powder to epoxy resin influences the mechanical and tribological properties of BFRP composites. Epoxy matrices, modified with 5%, 10%, and 15% weight fractions (wf.%) of copper powder, were reinforced with BFRP-type fabric, using a vacuum bag manufacturing method. Mechanical tests, including bending and tensile tests, showed notable improvements in tensile strength and flexural modulus due to copper addition, with higher copper (Cu) content enhancing ductility. Tribological tests using a pin-on-disk tribometer revealed reduced wear rates and an optimized coefficient of friction. Statistical analysis and 3D microscopy identified wear mechanisms such as delamination and protective copper film formation. The results highlight the significant potential of copper-modified BFRP composites for applications demanding superior mechanical and tribological performance. Full article

Combined Cycle Power Plants (CCPPs) generate electrical power through gas turbines and use the exhaust heat from those turbines to power steam turbines, resulting in 50% more power output compared to traditional simple cycle power plants. Predicting the full-load electrical power output ($P_E$) of a CCPP is crucial for efficient operation and sustainable development. Previous studies have used machine learning models, such as the Bagging and Boosting models to predict $P_E$. In this study, we propose employing Super Learner (SL), an ensemble machine learning algorithm, to enhance the accuracy and robustness of predictions. SL utilizes cross-validation to estimate the performance of diverse machine learning models and generates an optimal weighted average based on their respective predictions. It may provide information on the relative contributions of each base learner to the overall prediction skill. For constructing the SL, we consider six individual and ensemble machine learning models as base learners and assess their performances compared to the SL. The dataset used in this study was collected over six years from an operational CCPP. It contains one output variable and four input variables: ambient temperature, atmospheric pressure, relative humidity, and vacuum. The results show that the Boosting algorithms significantly influence the performance of the SL in comparison to the other base learners. The SL outperforms the six individual and ensemble machine learning models used as base learners. It indicates that the SL improves the generalization performance of predictions by combining the predictions of various machine learning models. Full article

Monitoring of real-time flow and defects in the vacuum-assisted resin infusion (VARI) process can provide important guidelines for full impregnation of dry reinforcement. A weak fiber Bragg grating array was employed to obtain quasi-distributed monitoring results in real-time. Sensitivity testing of different kinds of coated optical fiber sensors (OFs) was carried out first, and the polyacrylate-coated OF showed a greater wavelength-shift response than the polyimide-coated one. Then, two- and three-dimensional flow monitoring tests were carried out. During the resin-filling stage, three trends of strain curve were identpified in relation to the different placement setups of embedded OFs, the resin flow direction, and the different vacuum-bagging methods. The monitoring criteria were analyzed and the results were compared with the visual inspection, showing good agreement and indicating the ability of the fiber Bragg grating array. Finally, defects including dry spots and voids were introduced and reflected in the maximum changed strains of FBGs due to the smaller stress relaxation, indicating the potential to characterize the local flow state and permeabilities experimentally based on these quasi-distributed sensing methods. Full article

Vinyl ester resins are widely used as thermoset matrix materials for laminated composites, particularly in naval and automotive applications, due to their strength, chemical resistance, and ease of processing. However, their brittleness limits their use, especially in cold conditions. This study investigates the toughness of core–shell rubber (CSR)-modified resins in composites with natural fibers. This research compares the properties of the neat resin matrix and the CSR-modified matrix. After optimizing the resin curing process with catalysts, various treatments were tested to analyze their mechanical and thermal properties. Using the vacuum bagging process, flax and glass fibers were used as reinforcements to assess the effects of matrix modifications. Flax fibers were chosen for their sustainability as a potential alternative to glass fibers. Mechanical testing was performed, comparing the performance of flax-based composites to those with glass fibers. Water absorption tests on flax composites followed the ISO 62 standard. Additionally, interlaminar shear strength and SEM micrography studies were conducted to examine the morphology and fiber–matrix adhesion, linking the microscopic structure to mechanical properties. Results indicate that while glass-reinforced composites have superior properties, flax composites offer a sustainable alternative, making them a promising choice for future applications. Full article

Lactic acid bacteria (LAB) inoculants are commonly used in silage production, yet their effects on silage containing antimicrobial components, such as those found in Leonurus japonicus, remain less explored. Herein, the harvested alfalfa were thoroughly mixed with dried Leonurus japonicus Houtt. (LJH) at a ratio of 9:1 on a fresh weight basis and treated without (CK) or with a lactic acid bacterial inoculant (L; Lentilactobacillus buchneri). The mixtures were stored under anaerobic conditions in vacuum-sealed polyethylene bags for 30 days at ambient temperature. The L-treated silage exhibited high levels of water-soluble carbohydrates (4.98% dry matter (DM)) and acid detergent fiber (27.88% DM). Compared to that of treatment CK, treatment with L increased the acetic acid content of the silage, as a result of increased (p < 0.05) bacterial dominance and decreased (p < 0.05) bacterial richness indices (e.g., Pielou’s E, Shannon, and Simpson) in the pre-storage period. However, these changes gradually reduced as the storage length increased. Treatment L reshaped the bacterial community structure of silage, by increasing the prevalence of Lactobacillus and reducing relative abundances of Enterococcus and Weissella. However, the principal coordinate and Bray–Curtis index analyses illustrated that samples from the L-treated silages exhibited similarities to the CK samples post-fermentation. Overall, the effect of LJH on LAB was only observed in the later stages of fermentation, which did not sufficiently change the silage quality. Hence, using LJH in silage is vital for clean livestock production without compromising the function of LAB when mixed with alfalfa silage. Full article

(1) Background: Cultivating microgreens is emerging as an excellent market opportunity. Their easy, short, and sustainable production methods are the main reasons they are approved by growers. However, a feature that still prevents its further spread is the microbiological risk and their rapid senescence. The present study was conducted to evaluate the post-harvest storage and shelf life of arugula microgreens in different packaging through microbiological, physico-chemical, and sensory parameters; (2) Methods: Plants were stored at 5 °C in open air, vacuum sealed, and under modified atmosphere bags and tested at 0, 3, 5, 7, and 10 days; (3) Results: Microgreens stored in all packaging were safe for consumption within ten days. Regarding physical and chemical parameters, open packaging proved to be promising, with less weight loss and slower chlorophyll degradation. The sensory analysis demonstrated that the microgreens stored in the vacuum-sealed packaging showed a decrease in quality from the fifth day onwards for all attributes. However, the MAP presented good scores with a better visual quality, similar to the fresh microgreens. Full article