Search Results (1,129)

The soil of the Trifinio region, the tri-national territory between Guatemala, Honduras, and El Salvador, is damaged by the expansion of monoculture, which decreases fertility and causes problems for local farmers. Furthermore, the region also faces issues of erosion and soil contamination. As an alternative to soil cultivation, soilless systems can be adopted, not requiring fertile soil, and significantly increasing yields and resource use efficiency. To encourage soilless technique application in the region, the aim of this study was to compare 18 different substrate mixes to identify the most suitable for the local cultivation of cucumber (Cucumis sativus L.). The substrates were obtained comparing three rates of peat and compost (0%, 20% and 40%, by volume) in factorial combination, with the remaining being either coir or pumice (filling component). Plant growth, flower setting, physiological status (relative chlorophyll content and leaf temperature), and plant production were evaluated. Highest yield was achieved with 20% peat, while compost (20% and 40%) was able to increase fruit length and improve the relative chlorophyll content, but did not affect total production. However, when focusing on environmental sustainability as an important standpoint, a peat-free substrate should be utilized even though the results favored the 20% peat treatment for production. Considering that the differences in production in favor of 20% peat treatment were of limited practical relevance. In regard to the filling components (coir and pumice) yields were unaffected and only minor parameters were changed. Based on the results obtained, a substrate consisting of 60% coir and 40% compost resulted in the best option for the soilless cultivation of cucumber in the Trifinio region, with both materials being sustainable and easily available for local farmers. Full article

Omniphobic membranes have gained extensive attention for mitigating membrane wetting in robust membrane separation owing to the super-repulsion toward water and oil. In this study, a Teflon/PAI composite membrane with omniphobic characteristics was prepared by a vacuum-assisted dip-coating strategy on the PAI hollow fiber membrane. A series of characterizations on morphological structure, surface chemical composition, wettability, permeability, mechanical properties, and stability were systematically investigated for pristine PAI and Teflon/PAI composite membranes. Subsequently, the experiment was conducted to explore the oil–gas separation performance of membranes, with standard transformer oil containing dissolved gas as the feed. The results showed that the Teflon AF2400 functional layer was modified, and C-F covalent bonds were introduced on the composite membrane surface. The Teflon/PAI composite membrane exhibited excellent contact angles of 156.3 ± 1.8° and 123.0 ± 2.5° toward DI water and mineral insulating oil, respectively, indicating omniphobicity. After modification, the membrane tensile stress at break increased by 23.0% and the mechanical performance of the composite membrane was significantly improved. In addition, the Teflon/PAI composite membrane presented satisfactory thermal and ultrasonic stability. Compared to the previous membranes, the Teflon/PAI composite membrane presented a thinner Teflon AF2400 separation layer. Furthermore, the omniphobic membrane demonstrated anti-wetting performance by reaching the dynamic equilibrium within 2 h for the dissolved gases separated from the insulating oil. This suggests an omniphobic membrane as a promising alternative for oil–gas separation in monitoring the operating condition of oil-filled electrical equipment online. Full article

Bulk-fill composite resins (BFCRs) have emerged as efficient alternatives to conventional restorative systems, enabling placement in thicker increments without compromising polymerization; however, their comparative mechanical performance under clinically demanding conditions remains uncertain. This study aimed to evaluate and compare the mechanical properties—flexural strength (FS), elastic modulus (EM), strain (ε), and displacement (δ)—of three high-viscosity bulk-fill resins: Filtek One™ Bulk Fill (3M ESPE), Tetric^® N-Ceram Bulk Fill (Ivoclar Vivadent), and Opus™ Bulk Fill (FGM). Thirty specimens (n = 10 per group) were fabricated according to ISO 4049:2019 and subjected to three-point bending tests. Statistical analysis included Shapiro–Wilk testing for normality, one-way analysis of variance (ANOVA) with Tukey’s post hoc comparisons, multivariate analysis of variance (MANOVA), and Spearman’s correlation. Filtek One™ Bulk Fill exhibited the highest FS 142.5 megapascals (MPa) and EM 4.2 gigapascals (GPa), with significant differences compared to Tetric^® N-Ceram Bulk Fill and Opus™ Bulk Fill (p < 0.001). Opus™ Bulk Fill demonstrated greater deformation capacity before fracture (p = 0.015). MANOVA revealed a significant effect of resin type on overall mechanical behavior (Wilks’ λ = 0.132; p < 0.001). Strong correlations were observed between strength and stiffness (ρ = 0.82), and between stiffness and deformation (ρ = –0.68). These findings confirm that BFCRs differ significantly in mechanical behavior, with Filtek One™ Bulk Fill exhibiting superior stiffness and resistance, while Opus™ Bulk Fill showed greater deformation capacity. Such differences support material selection based on the functional and anatomical demands of restorations, contributing to improved clinical performance and longevity. Full article

Hydrogen peroxide is a promising oxidizer and monopropellant for space propulsion, offering a green alternative to conventional propellants. In combination with microencapsulated hydrocarbon fuels, a new type of monopropellant can be formed that unites the high specific impulse of a bipropellant with the efficient hardware of a monopropellant. However, the stabilization of these microcapsule/hydrogen peroxide mixtures is problematic as they tend to separate after a short period of time. This work uses organic gelling agents to stabilize these mixtures by creating hydrogen peroxide gels. For this, the compatibility of hydrogen peroxide with several gelling agents was investigated and found to be suitable. Next, the dispersion stability of microcapsule/gel dispersions was examined and showed no sign of destabilization over four weeks or at high accelerations at 50× g in the centrifuge, even with gelling agent concentrations as low as 0.1%. A formulation with a polyacrylic acid-based gelling agent at a concentration of 0.3% showed favorable characteristics and good processability. Together with a subsequent rheological characterization of the gels, these results are critical for the further development of the fuel-filled microcapsule/hydrogen peroxide monopropellant. The hydrogen peroxide gel formulations developed in this study could also have potential applications beyond the scope of this work. Full article

Modern cosmology continues to struggle with unresolved questions concerning the origins of dark matter and dark energy. To explore these challenges, this study presents the Source Energy Field Theory (SEFT)—a new theoretical framework that offers an alternative view of how cosmic structures may form and evolve. SEFT envisions the universe as filled with a fundamental energy field, where the observed cosmological redshift does not result from accelerated expansion but rather emerges from the distance-dependent modulation of the energy field and the curvature produced by this field. To evaluate this idea, a nonlinear wave equation was developed to connect redshift with right ascension, declination, and distance. The model was optimized using 1701 observational data points from the Pantheon+ and SH0ES samples, which include Type Ia supernovae and Cepheid variables spanning distances from 6.3 to 17,241 Mpc. Its performance was compared with that of the standard ΛCDM model. SEFT achieved a slightly lower root-mean-square error (145.521 vs. 147.665 Mpc), a marginally higher determination coefficient (R² = 0.9910 vs. 0.9908), and significantly improved information criteria values (ΔAIC = −41.753, ΔBIC = −19.997). These results provide robust statistical support for SEFT and suggest that it can complement—and potentially extend—the ΛCDM paradigm in describing the structure and evolution of the universe. Full article

Large-format additive manufacturing (LFAM) is an enabling manufacturing technology capable of producing large parts with highly complex geometries for a wide variety of applications, including automotive, infrastructure/construction, and aerospace mold and tooling. In the past decade, the LFAM industry has seen widespread use of bio-based, glass, and/or carbon fiber reinforced thermoplastic composites which, when printed, serve as a lower-cost alternative to metallic parts. One of the highest-volume materials utilized by the industry is carbon fiber (CF)-filled polycarbonate (PC), which in out-of-autoclave applications can achieve comparable mechanical performance to metal at a significantly lower cost. Previous work has shown that if this material is recovered at various points throughout the manufacturing process for both the lab and pilot scale, it can be mechanically recycled with minimal impacts on the functional performance and printability of the material while significantly reducing the feedstock costs. End-of-life (EOL) CF-PC components were processed through industrial shredding, melt compounding, and LFAM equipment, followed by evaluation of the second-life material properties. Experimental assessments included quantitative analysis of fiber length attrition, polymer molecular weight degradation using gel permeation chromatography (GPC), density changes via pycnometry, thermal performance using dynamic mechanical analysis (DMA), and mechanical performance (tensile properties) in both the X- and Z-directions. Results demonstrated a 24.6% reduction in average fiber length compared to virgin prints, accompanied by a 21% decrease in X-direction tensile strength and a 39% reduction in tensile modulus. Despite these reductions, Z-direction tensile modulus improved by 4%, density increased by 6.8%, and heat deflection temperature (HDT) under high stress retained over 97% of its original value. These findings underscore the potential for integrating mechanically recycled CF-PC into industrial LFAM applications while highlighting the need for technological innovations to mitigate fiber degradation and enhance material performance for broader adoption. This critical step toward circular material practices in LFAM offers a pathway to reducing feedstock costs and environmental impact while maintaining functional performance in industrial applications. Full article

Maize (Zea mays L.) silage’s forage quality significantly impacts dairy animal performance and the profitability of the livestock industry. Recently, using uncrewed aerial vehicles (UAVs) equipped with advanced sensors has become a research frontier in maize high-throughput phenotyping (HTP). However, extensive existing studies only consider a single sensor modality and models developed for estimating forage quality are single-task ones that fail to utilize the relatedness between each quality trait. To fill the research gap, we propose MUSTA, a MUlti-Sensory feature fusion model that utilizes MUlti-Task learning and the Attention mechanism to simultaneously estimate dry matter yield and multiple nutritive values for silage maize breeding hybrids in the field environment. Specifically, we conducted UAV flights over maize breeding sites and extracted multi-temporal optical- and LiDAR-based features from the UAV-deployed hyperspectral, RGB, and LiDAR sensors. Then, we constructed an attention-based feature fusion module, which included an attention convolutional layer and an attention bidirectional long short-term memory layer, to combine the multi-temporal features and discern the patterns within them. Subsequently, we employed multi-head attention mechanism to obtain comprehensive crop information. We trained MUSTA end-to-end and evaluated it on multiple quantitative metrics. Our results showed that it is capable of practical quality estimation results, as evidenced by the agreement between the estimated quality traits and the ground truth data, with weighted Kendall’s tau coefficients (τ_w) of 0.79 for dry matter yield, 0.74 for MILK2006, 0.68 for crude protein (CP), 0.42 for starch, 0.39 for neutral detergent fiber (NDF), and 0.51 for acid detergent fiber (ADF). Additionally, we implemented a retrieval-augmented method that enabled comparable prediction performance, even without certain costly features available. The comparison experiments showed that the proposed approach is effective in estimating maize silage yield and nutritional values, providing a digitized alternative to traditional field-based phenotyping. Full article

To address the challenges associated with Ordinary Portland Cement (OPC) in mine backfilling, including high costs, the large carbon footprint, and performance limitations, a novel cementitious powder (CP) based on alkali-activated slag is developed in this work. The mechanical performance and microstructural strengthening mechanism of this CP as a substitute for OPC in cemented copper tailing backfill (CTB) were systematically evaluated. The effects of key parameters, including the solid content (SC), tailing-to-cement ratio (TCR), and curing age (CA), were investigated using uniaxial compressive strength (UCS) tests and scanning electron microscopy (SEM) analysis. The results demonstrate that the novel binder exhibits superior performance. At a solid content of 73%, the CTB prepared with CP at a TCR of 10 or 12 achieved a compressive strength comparable to or exceeding that of the OPC-based counterpart with a TCR of 8. This represents a 33% reduction in binder dosage without sacrificing performance. The UCS of the CTB increased significantly with a decreasing TCR and an increasing CA, with the most rapid strength development observed during the early curing stages (≤7 days). The stress–strain behavior transitioned from plastic yielding to strain-softening with prolonged curing, and the macroscopic failure was predominantly governed by tensile cracking. Microstructural analysis revealed that the strength development of the CTB originates from the continuous formation of hydration products, such as calcium-silicate-hydrate (C-S-H) gel and ettringite. These products progressively fill pores and encapsulate tailing particles, creating a dense and interlocking skeletal structure. A lower TCR and a longer CA promote the formation of a more integrated and compact micro-network, thereby enhancing the macroscopic mechanical strength. This study confirms the viability of the slag-based binder as a sustainable alternative to OPC in mining backfill applications, providing a critical theoretical basis and technical support for the low-cost, eco-friendly utilization of mining solid waste. Full article

Constructed wetland beds are in widespread use for treating wastewater. Their use is well known, and current research is focused on the use of new substrates and different bed configurations, or on assisting the oxygenation process. The authors conducted an extended experiment using VF CWs with two types of filling: gravel, and a waste material called Certyd. Certyd is produced in the sintering process of coal ash, and is a type of waste from combined heat and power (CHP) plant operation. Both beds worked in parallel in order to compare their effectiveness, taking into account seasonality. The obtained database was used for statistical modeling using the P-k-C* model with correction for a trend change at a specific temperature. The obtained models were characterized by good fits to measured quantities. The study demonstrates that Certyd is a viable alternative to gravel. At all temperatures, a bed filled with Certyd has better treatment efficiency. When the temperature at which the trend changes is high, then no additional temperature dependence is recorded when this temperature is exceeded; otherwise, there is a steeper dependency below this temperature, especially in the case of the gravel-filled bed. This result suggests application of Certyd for beds located in colder climates. Full article

This study examines the potential of jute–sisal (JS) fibre, both coated and uncoated, as a sustainable alternative to solar panels with polyethylene terephthalate (PET) back sheets. The coated version was developed using a zeolite–polyester resin composite to enhance thermal performance. The investigation was carried out in two phases: controlled laboratory testing using a solar-cell tester and a 90-day real-world evaluation under natural environmental conditions. In controlled conditions, solar panels with coated JS (CJS) fibre back sheets exhibited improved electrical performances compared to PET panels, including higher current (1.23 A), voltage (12.79 V), maximum power output (14.79 W), efficiency (13.47%), and fill factor (94.03%). Lower series resistance and higher shunt resistance further indicated superior electrical characteristics. Under real-world conditions, CJS panels consistently outperformed PET-based panels, showing a 6% increase in current and an 8% increase in voltage. The model showed strong agreement with the experimental results. These findings suggest that coated JS fibre is a viable, eco-friendly alternative to PET for back sheets in solar panels. Further research should examine its long-term durability, environmental resistance, and commercial scalability. Full article

This study investigates the mechanical and thermal properties of polypropylene (PP) composites incorporating pumice, a naturally occurring porous volcanic rock with high SiO₂ content, sourced from three regions in Türkiye (Nevşehir, Alaçatı, and Kütahya). Pumice was processed to particle sizes below 10 microns to maximize nucleating effectiveness, and composites were fabricated by melt compounding. The distinct mineralogical composition, porosity, and surface chemistry of the pumice samples enabled systematic evaluation of how regional variations influence crystallization and mechanical performance. A multi-analytical characterization approach, including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and standardized mechanical tests (tensile, flexural, and impact), was applied. Results revealed that Alaçatı pumice at 0.1 wt% increased the impact strength of PP by about 11%, while maintaining stiffness. This demonstrates that pumice, unlike conventional fillers, can simultaneously enhance toughness and rigidity. Thermal analysis confirmed improved stability, with higher degradation onset and maximum decomposition temperatures observed in pumice-filled PP. DSC results indicated that certain pumice loadings promoted nucleation and increased crystallinity, while excessive amounts disrupted chain packing. SEM examinations confirmed uniform dispersion at low loadings, with agglomeration at higher levels reducing impact resistance. This work provides the first systematic demonstration of pumice powders as effective nucleating agents in PP, combining regional mineralogical diversity with measurable performance benefits. These findings indicate that pumice can serve as a sustainable, low-cost alternative to conventional nucleating agents, with potential applications in polymer components requiring improved toughness and thermal stability. Full article

In this study, the thermal and structural behavior of battery module components produced from polymer-based composites was systematically evaluated using coupled Moldflow 2016 and ANSYS Fluent 2024 simulations. Three thermoplastics—metal-flake-reinforced PC+ABS (Polycarbonate/Acrylonitrile Butadiene Styrene), carbon-fiber-reinforced PEEK (Polyether Ether Ketone), and hybrid mineral-filled PP (Polypropylene)—were investigated as alternatives to conventional aluminum components. Moldflow simulations enabled the assessment of injection molding performance by determining injection pressure, volumetric shrinkage, warpage, residual stress, flow front temperature, and part weight. PEEK exhibited the best dimensional stability, with minimal warpage and shrinkage, while PP showed significant thermomechanical distortion, indicating poor resistance to thermally induced deformation. For thermal management, steady-state simulations were performed on a 1P3S pouch cell battery configuration using the NTGK/DCIR model under a constant heat load of 190 W. Material properties, including temperature-dependent thermal conductivity, density, and specific heat capacity, were defined based on validated databases. The results revealed that temperature distribution and Joule heat generation were strongly influenced by thermal conductivity. While aluminum exhibited the most favorable thermal dissipation, PC+ABS closely matched its electrical performance, with only a 1.3% lower average current magnitude. In contrast, PEEK and PP generated higher cell core temperatures (up to 20 K) due to limited heat conduction, although they had comparable current magnitudes imposed by the energy-conserving model. Overall, the findings indicate that reinforced thermoplastics, particularly PC+ABS, can serve as lightweight and cost-effective alternatives to aluminum in mid-range battery modules, providing similar electrical performance and thermal losses within acceptable limits. Full article

Nuts are nutrient-rich foods that help reduce the risk of coronary heart disease (CHD), but their potential contamination with aflatoxins (AFs) may increase the risk of liver cancer. In this study, the European Benefit–Risk Analysis for Foods (BRAFO) framework was used to evaluate both the health risks and benefits of nut consumption among Chinese adults. Based on the actual consumption patterns of nuts among the Chinese population, the current consumption level was set as the reference scenario (4.66 g/day), and three alternative scenarios were simulated with a daily nut consumption of 10, 20, and 30 g, respectively. Dose–response relationships were established using a two-stage dose–response analysis for nut consumption and CHD risk, and a one-stage dose–response analysis for aflatoxin B1 (AFB1) exposure and liver cancer risk. A Monte Carlo probabilistic model quantified the CHD prevention benefits and liver cancer risks associated with AF exposure. Disability-Adjusted Life Year (DALY) analysis indicated net health benefits in all scenarios, with nut consumptions of 10, 20, and 30 g/day reducing DALYs per 100,000 population by 104.39, 143.63, and 181.47 in men, and by 58.79, 81.29, and 102.94 in women, respectively. A nut consumption of 10 g/day was recommended for Chinese adults, considering both health benefits and the risk of AF exposure. This study presents the first application of the BRAFO framework to evaluate the net health effect of nut consumption in a Chinese population, filling a critical gap in the risk–benefit assessment of nut consumption. Full article

Smart and sustainable cities are often assessed using indicator-based models. However, most existing systems evaluate cities as a whole, offering limited support for project-level decision-making, particularly in small and medium-sized cities with scarce resources. This study aims to fill this gap by developing a comprehensive indicator framework tailored to the evaluation of smart city projects, designed to guide investment choices and support evidence-based planning. To build this framework, a systematic review of international indicator systems was conducted, compiling and refining over 1200 indicators into a unified taxonomy. The analysis revealed structural imbalances, with environmental and social dimensions prevailing over economic and governance aspects, and confirmed substantial redundancies, with nearly one-third of indicators overlapping. Using project actions as an analytical lens, gaps were detected and 73 evaluation areas defined. From these, anticipated impact indicators were developed and linked to corresponding performance metrics. Beyond consolidating fragmented systems, the framework provides a practical and balanced tool for multidimensional project assessment. An initial empirical pre-validation demonstrated its coverage and usability, reinforcing its potential to support planners and policymakers in comparing investment alternatives. Unlike traditional ranking or maturity models, it directly bridges the gap between abstract smart city strategies and tangible, project-level outcomes. Full article

Renewable energy sources are among the most promising alternatives to fossil fuels, and solar thermal energy stands out due to its high conversion efficiency and direct thermal utilization. The performance of solar collectors is evaluated under standardized procedures, including ISO 9806:2025. In the Republic of Korea, KS B 8295:2023 is applied for certification; however, it lacks clear guidance on the selection of the working fluid mass flow rate during experimental testing. This study experimentally investigates the thermal performance of a double-glass evacuated tube solar collector under varying flow rates, tested in accordance with both KS B 8295:2023 and ISO 9806:2025 standards. Three flow rates (0.042, 0.067, 0.092 kg/s) were tested at four inlet temperature levels. Unlike most previous studies, which were primarily based on simulations and lacked standardized experimental validation, this work provides empirical results obtained under fully standard testing conditions, thereby filling an important research gap. Instantaneous efficiency curves were derived, showing that increasing the flow rate enhanced the average thermal output by approximately 6%. These results highlight the necessity of defining optimal flow rate conditions in KS B 8295:2023, and the empirical correction factor proposed herein can support future standard revisions and promote international harmonization. Full article