Search Results (517)

Decarbonisation of the aviation sector is essential for achieving global-climate targets, with hydrogen propulsion emerging as a viable alternative to battery–electric systems for vertical flight. Unlike previous studies focusing on clean-sheet eVTOL concepts or fixed-wing platforms, this work provides a comprehensive retrofit evaluation of a two-seat light helicopter (Cabri G2/Robinson R22 class) to a hydrogen–electric hybrid powertrain built around a Toyota TFCM2-B PEM fuel cell (85 kW net), a 30 kg lithium-ion buffer battery, and 700 bar Type-IV hydrogen storage totalling 5 kg, aligned with the Vertical Flight Society (VFS) mission profile. The mass breakdown, mission energy equations, and segment-wise hydrogen use for a 100 km sortie are documented using a single main rotor with a radius of R = 3.39 m, with power-by-segment calculations taken from the team’s final proposal. Screening-level simulations are used solely for architectural assessment; no experimental validation is performed. Mission analysis indicates a 100 km operational range with only 3.06 kg of hydrogen consumption (39% fuel reserve). The main contribution is a quantified demonstration of a practical retrofit pathway for light rotorcraft, showing approximately 1.8–2.2 times greater range (100 km vs. 45–55 km battery-only baseline, including respective safety reserves). The Hawk demonstrates a 28% reduction in total propulsion system mass (199 kg including PEMFC stack and balance-of-plant 109 kg, H₂ storage 20 kg, battery 30 kg, and motor with gearbox 40 kg) compared to a battery-only configuration (254.5 kg battery pack, plus equivalent 40 kg motor and gearbox), representing approximately 32% system-level mass savings when thermal-management subsystems (15 kg) are included for both configurations. Full article

The calculation of the limiting efficiency and structural optimization of solar cells based on the detailed balance principle is systematically investigated in this study. Through modeling and numerical simulations of various cell architectures, the theoretical efficiency limits of these structures under AM1.5G (Air Mass 1.5 Global) spectrum were quantitatively evaluated. Through a comprehensive consideration of the effects of bandgap and composition, the Al_0.03Ga_0.97As/Ge (1.46 eV/0.67 eV) cell configuration was determined to achieve a high theoretical efficiency of 43.0% for two-junction cells while maintaining satisfactory lattice matching. Furthermore, the study proposes that incorporating a Ga_0.96In_0.04As (8.3 nm)/GaAs_0.77P_0.23 (3.3 nm) strain-balanced multiple quantum wells (MQWs) structure enables precise bandgap engineering, modulating the effective bandgap to the optimal middle-cell value of 1.37 eV, as determined by graphical analysis for triple junctions. This approach effectively surpasses the efficiency constraints inherent in conventional bulk-material III–V semiconductor solar cells. The results demonstrate that an optimized triple-junction solar cell with MQWs can theoretically achieve a conversion efficiency of 51.5%. This study provides a reliable theoretical foundation and a feasible technical pathway for the design of high-efficiency solar cells, especially for the emerging MQW-integrated III–V semiconductor tandem cells. Full article

Background/Objectives: Falls are a leading cause of morbidity and mortality in older adults, even among those who are physically active. This study examined the associations between skeletal muscle mass, muscle strength, and muscle power and fall risk in physically active, community-dwelling older adults. Methods: A cross-sectional analysis was conducted with 280 participants (71.9 ± 5.3 years; 75% women) enrolled in the Stay Up–Falls Prevention Project. Assessments included skeletal muscle mass (anthropometric prediction equation), handgrip strength, lower limb strength and power (Five Times Sit-to-Stand test, 5×STS), and fall history over the past 12 months. Muscle power was calculated from 5×STS performance using the equation proposed by Alcazar and colleagues. Logistic regression models and receiver operating characteristic (ROC) curve analyses were performed. Results: Overall, 26.4% of participants reported at least one fall in the previous year, with a higher prevalence among women (28.9%) than men (18.8%). Fallers showed significantly lower handgrip strength (23.1 vs. 25.4 kg, p = 0.022) and poorer lower limb strength (9.2 vs. 8.7 s, p = 0.007) compared with non-fallers. However, no significant differences were found for skeletal muscle mass or sit-to-stand–derived power. In multivariable models adjusted for age, sex, body mass index, comorbidities, and medications, lower limb strength remained the only independent variable associated with fall status (OR = 1.78, 95% CI: 1.11–2.85, p = 0.016). ROC analysis confirmed fair discriminative capacity for 5×STS performance (AUC = 0.616, p = 0.003), with an optimal cut-off of 8.62 s (sensitivity = 78.4%, specificity = 33.0%). Handgrip strength, muscle mass, and power did not show independent associations with fall status. Conclusions: These findings indicate that the 5×STS test provides a simple, cost-effective, and functional indicator for fall-risk stratification in physically active older adults. Clinicians should consider the 5×STS as a sensitive functional indicator that contributes to fall risk stratification, ideally combined with complementary assessments (e.g., balance, gait, cognition) to improve risk stratification and guide preventive interventions in ageing populations. Full article

The purpose of this study was to examine morphological asymmetries in male youth judokas using an integrated assessment combining three-dimensional (3D) body scanning and bioelectrical impedance analysis (BIA), and to determine how these asymmetries relate to judo-specific performance. Twenty-seven competitive male youth judokas were evaluated for bilateral girth, segmental length, and lean mass asymmetries across upper- and lower-limb segments. The Absolute Asymmetry index, expressed as a percentage for individual body segments, and the average body symmetry across all variables were calculated, and associations with performance were assessed using the Special Judo Fitness Test (SJFT). Significant right-dominant asymmetries were found in elbow girth p < 0.001, forearm girth p < 0.001, thigh girth p = 0.028, and leg muscle mass p = 0.008. Upper-limb asymmetries were the primary contributors to total-body asymmetry, reflecting the unilateral gripping and rotational demands typical in judo. Only calf girth asymmetry was significantly associated with SJFT performance, with greater asymmetry linked to poorer outcomes, indicating a specific rather than general asymmetry–performance relationship (r = 0.405; p = 0.037). These findings underscore the importance of early detection of segment-specific asymmetries and suggest that rapid digital anthropometry is a practical tool for monitoring morphological development in youth judokas. Early targeted interventions may support balanced technical execution, enhance performance, and reduce the risk of uneven loading patterns as athletes progress to higher age categories and competition levels. Full article

Industrial deployment of photocatalysis for recalcitrant wastewater treatment remains constrained by economic uncertainty and scale-up limitations. This study first reviews the current technological routes and application status of photocatalytic processes and then addresses the key obstacles through a quantitative techno-economic assessment (TEA) of a full-scale (10,000 m³/d) photocatalytic wastewater treatment plant. A process-level model integrating mass- and energy-balance calculations with equipment sizing was developed for a 280 kW UVA-LED reactor using Pt/TiO₂ as the benchmark catalyst. The framework quantifies capital (CAPEX) and operating (OPEX) expenditures and evaluates the overall economic performance of the photocatalytic treatment system. Sensitivity analysis reveals that the catalyst replacement interval and electricity tariffs are the principal economic bottlenecks, whereas improvements in catalyst performance alone provide limited cost leverage. Furthermore, the analysis indicates that supportive policy mechanisms such as carbon-credit incentives and electricity subsidies could substantially enhance economic feasibility. Overall, this work establishes a comprehensive integrated TEA framework for industrial-scale photocatalytic wastewater treatment, offering actionable design parameters and cost benchmarks to guide future commercialization. Full article

This paper presents an energy-focused analysis of structural materials used in passenger cars, with a particular emphasis on the impact of construction materials on total energy consumption throughout the vehicle’s life cycle. Three production periods (2000, 2010, and 2020) were analysed for B- and C-segment vehicles using inventory data from Life Cycle Assessment databases, the scientific literature, and certified dismantling stations. The embodied energy of key material groups—steel, aluminium, plastics, and other materials—was calculated based on representative mass shares and material-specific energy intensity indicators. The computational model was supplemented with statistical analyses (Kolmogorov–Smirnov test, Levene’s test, ANOVA, and Tukey’s post hoc tests) to verify whether observed temporal trends were statistically significant. The results indicate that total material-related energy inputs increased from approximately 57 GJ to 64 GJ per vehicle, while the specific energy intensity per kilogram decreased from 47.6 MJ/kg to 42.6 MJ/kg. Aluminium exhibited a pronounced reduction in unit energy intensity due to the rising share of secondary materials, whereas plastics and other materials showed substantial increases. Steel remained the largest contributor in absolute terms because of its dominant mass share. This study highlights the growing importance of the production phase in the environmental balance of modern vehicles, particularly in the context of the rising share of lightweight materials and recycling-based components. The results emphasise the importance of energy-efficient material use and underscore the significance of material selection and recycling strategies in reducing energy demand within the automotive sector. Full article

The rates of CO₂ mass deposition onto cryogenically cooled surfaces are crucial for CO₂ removal processes that rely on cryogenics. A dedicated experimental setup was constructed to measure CO₂ mass deposition rates under controlled conditions. Experiments were carried out with both pure CO₂ and CO₂/N₂ mixtures, growing frost layers up to 8 mm thick. Results demonstrated that heat transfer through the frost layer significantly slows down the mass deposition process. Furthermore, it was found that the addition of N₂ to the gas phase has a considerable influence on mass deposition rates, because it introduces an additional mass transfer resistance toward the frost surface. To describe the experimentally observed behavior, a frost growth model based on mass and energy balances was developed. Expressions for the frost density as a function of the frost temperature and for the effective frost conductivity as a function of the frost density were derived and implemented in the model. When accounting for drift fluxes, the model accurately captures the behavior observed in experiments. The findings of this work highlight the significant impact of heat transfer limitations on processes that accumulate a thick solid CO₂ layer, such as continuously cooled heat exchangers. Conversely, technologies like cryogenically refrigerated packed beds do not develop a thick solid CO₂ layer; calculations showed that a frost layer of 3.24·10⁻⁵ m is formed, resulting in a Biot number well below 0.01, indicating that heat transfer in the frost layer is not limiting. Full article

Due to the strong electronegativity of oxygen ions, the valence band maximum (VBM) that is derived from the O 2p orbital leads to strong localization, as well as further heavy hole mass and low hole mobility, which makes it extremely difficult to obtain high-conductivity p-type transparent conductive materials. Herein, we propose the strategy of multiple anions through the introduction of weaker electronegative nitrogen, in consideration of the delocalization on VBM, as well as the stability of octahedral anion cages. As such, first-principles calculations in the framework of density functional theory (DFT) are used for this work. Crystal structure prediction software USPEX (version 2023.0) was adopted to investigate the N-O appropriate ratio in CaTiO_3−xN_x (0 ≤ x ≤ 1) to balance the high transmission of light and highly favorable dispersion at the VBM. Furthermore, the p-type TCO performance of CaTiO_3-xN_x was evaluated based on the hole effective mass, hole mobility, and conductivity. The effectiveness of modulating p-type TCO through N-O multiple anions was also evaluated through defect formation energy and ionization energy. Ultimately, the construction of a CaTiO_3-xN_x/Si heterojunction and band alignment were considered for practical application. This approach attempts to boost the diversity of p-type perovskite-based TCOs and opens a new perspective for engineering and innovative material design for sustainable TCOs demand. Full article

Documenting baseline elemental distribution patterns in crops under non-contaminated conditions provides a physiological reference for understanding constitutive metal homeostasis. This study compared the internal allocation of elements in sunflower (Helianthus annuus), wheat (Triticum aestivum), and maize (Zea mays) grown in soil with a specific geochemical profile. Soil was characterized using X-ray Fluorescence Spectroscopy (XRF) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Plants were grown under controlled conditions, and elemental concentrations in roots and shoots were quantified to calculate Bioaccumulation (BCF) and Translocation (TF) Factors. Soil analysis confirmed nickel (42.6 mg kg⁻¹) and copper (32.8 mg kg⁻¹) concentrations within typical global ranges for uncontaminated soils. Species exhibited different distribution tendencies: sunflower showed balanced root–shoot allocation for nickel (TF = 1.00); wheat demonstrated pronounced root retention of nickel and copper (TF < 0.5); and maize exhibited preferential translocation of copper (TF = 0.76) alongside root retention of nickel. Concentrations of lead, selenium, and silver were minimal across all species. The study delineates different species-specific tendencies in internal elemental allocation under given growth conditions. These patterns represent baseline physiological behaviors rather than responses to contamination, providing a comparative dataset that contributes to the understanding of crop ionomics and informs the interpretation of tissue metal concentrations in relation to soil conditions. Full article

Background: Lidocaine, classified as an amide-type agent, and tetracaine, designated as an ester-type agent, are frequently co-formulated for dermatologic procedures. Despite the extensive literature on the pharmacokinetics (PK) of these substances, there is a paucity of head-to-head comparisons of intravenous (IV) and topical administration in the same preclinical model. Absolute bioavailability (F%) is imperative for optimizing formulation design and safety. Methods: A single-dose, single-sequence, three-period pilot study was performed in male Göttingen mini-pigs. The first period of the study involved the intravenous bolus administration of lidocaine HCl and tetracaine HCl, with a dosage of 1 mg/kg for each agent. In Period 2, the topical application of Pliaglis (a combination of 7% lidocaine and 7% tetracaine, with a concentration of 10 g/100 cm² and a duration of 60 min) was utilized. In Period 3, the pharmacokinetic profile of Z4T4L4 (a formulation comprising 4% lidocaine HCl and 4% tetracaine HCl) was assessed under the same experimental conditions. Blood samples were collected up to 24 h after the administration of the drug; skin biopsies were obtained 90 min after the application of the test substance. Plasma and skin concentrations were measured by means of validated liquid chromatography–tandem mass spectrometry (LC–MS/MS). PK parameters were derived using a noncompartmental analysis approach, while F% was calculated through AUC comparison with IV dosing. Results: Subsequent to intravenous administration, the mean elimination half-lives of lidocaine and tetracaine were determined to be 1.62 h and 1.85 h, respectively. Pliaglis demonstrated higher skin concentrations of lidocaine (358 μg/g) and tetracaine (465 μg/g) compared to Z4T4L4 (33.6 μg/g and 46.1 μg/g, respectively). Despite lower skin levels, Z4T4L4 produced higher F% (lidocaine: 1.98% vs. 1.41%; tetracaine: 3.34% vs. 1.26%). The time to maximum plasma concentration (T_max) for lidocaine was found to be 2–4 h (Pliaglis) and 2–8 h (Z4T4L4), while for tetracaine, it was 1–8 h (Pliaglis) and 2–8 h (Z4T4L4). Conclusions: In this preliminary study, which included three subjects, Z4T4L4 exhibited a numerical tendency towards increased systemic bioavailability in comparison with Pliaglis. This observation was noted despite the fact that Z4T4L4 resulted in markedly lower skin concentrations. Due to the exploratory nature of the pilot study (n = 3), observed differences are reported as numerical trends. The data suggest that Z4T4L4 may enhance systemic absorption while reducing skin retention, highlighting a potential formulation-dependent dissociation between local concentration and systemic bioavailability. These preliminary findings provide in vivo evidence of a divergence between eutectic-based tissue retention and enhancer-driven systemic flux. This highlights that formulation design fundamentally dictates the safety profile of local anesthetics, necessitating a balance between local efficacy and systemic safety. Full article

Glacier surface albedo controls solar energy absorption and Arctic mass balance, yet comprehensive modelling approaches remain limited. This study develops and validates multiple modelling frameworks for glacier albedo prediction using automatic weather station (AWS) data from Hansbreen and Werenskioldbreen in southern Svalbard during the 2011 ablation season. We compared three point-based approaches across elevation zones. At lower elevations (190 m), linear regression models emphasising snowfall probability or temperature controls achieved excellent performance (R² = 0.84–0.86), with snowfall probability contributing 65% and daily positive temperature contributing 86.3% feature importance. At higher elevations (420 m) where snow persists, neural networks proved superior (R² = 0.65), with positive degree days (72.5% importance) driving albedo evolution in snow-dominated environments. Spatial modelling extended point predictions across glacier surfaces using elevation-dependent probability calculations. Validation with Landsat 7 imagery and multi-algorithm comparison (n = 5) revealed that while absolute albedo values varied by 12% (0.54–0.60), temporal dynamics showed remarkable consistency (27.8–35.2% seasonal decline). Point-to-pixel validation achieved excellent agreement (mean absolute difference = 0.03 ± 0.02, 5.3% relative error). Spatial validation across 173,133 pixel comparisons demonstrated good agreement (r = 0.62, R² = 0.40, RMSE = 0.15), with an accuracy of reproducing temporal evolution within 0.001–0.021 error. These findings demonstrate that optimal glacier albedo modelling requires elevation-dependent approaches combining physically based interpolation with machine learning, and that temporal pattern reproduction is more reliably validated than absolute values. The frameworks provide tools for understanding albedo-climate feedback and improving mass balance projections in response to Arctic warming. Full article

Municipal wastewater (MWW) was treated using a microalgal–bacterial consortium without mechanical aeration. An inoculum for the reactor was prepared by acclimatizing Chlorella vulgaris to MWW and supplementing with a small amount of activated sludge. The hydraulic retention time (HRT) and solids retention time (SRT) were progressively reduced from 6.67 to 1.17 d and from 10 to 6.67 d, respectively, to test the process robustness under realistic MWW operation. The COD removal efficiency was 88% at 0.23 kg-COD/m³/d. Mass balance suggested the major nitrogen and phosphorus removal mechanism as assimilation. A high percentage (80%) of oxidized nitrogen indicated an efficient nitrification at all HRTs. Inorganic carbon (IC) balance calculation explained the observed IC dynamics. The chlorophyll a-to-mixed liquor volatile suspended solids (MLVSS) ratio and percentage of nitrite responded to IC limitation and supplementation. The mixed liquor exhibited excellent settleability (sludge volume index: 42 mL/g) with dense algal–bacterial flocs. An increased organic loading rate, however, reduced daytime dissolved oxygen, suggesting limitation under non-aerated conditions. These findings demonstrate the potential of microalgal–bacterial systems to achieve efficient COD removal and nitrification at realistic HRTs without aeration while emphasizing the importance of IC management. Full article

Objective: This study aims to analyze relationships between body composition, biochemical parameters, and cardiac function in young adults to identify mechanisms of cardiac dysfunction in obesity. Methods: This is a cross-sectional study of 60 young adults (mean age 20.4 years) divided into healthy (n = 29) and overweight/obese (n = 31) groups. Body composition was assessed using bioelectrical impedance analysis. We calculated the SMM-to-Fat ratio (skeletal muscle mass %/body fat %) as a continuous composite metric. Cardiac function was evaluated using 3D speckle-tracking echocardiography, with a 3D global circumferential strain pre-specified as the primary endpoint. Results: The obese group showed unfavorable body composition with lower SMM% (38.0 ± 10.8 vs. 47.1 ± 5.6%), higher body fat% (28.3 ± 12.6 vs. 16.0 ± 8.3%), and lower SMM-to-Fat ratio (2.1 ± 2.3 vs. 4.8 ± 5.1; all p < 0.001). C-peptide was 75% higher (p < 0.001), indicating compensatory hyperinsulinemia. The primary endpoint showed impairment in the obese group (−19.8 ± 4.7 vs. −22.2 ± 2.9%; p = 0.023, d = 0.61), while longitudinal strain was preserved, indicating selective mid-wall dysfunction. The SMM-to-Fat ratio demonstrated a stronger association with circumferential strain (r = −0.467, p = 0.008) than SMM% alone (r = −0.414, p = 0.021) and remained an independent predictor in multivariable analysis (β = −0.88, p = 0.019), whereas SMM% did not achieve significance (p = 0.159). Comprehensive analysis revealed correlation reversal across all body composition parameters between groups, with minerals% and total body water% emerging as additional independent predictors. Conclusions: Young obese adults exhibit selective mid-wall cardiac dysfunction. The SMM-to-Fat ratio, representing muscle–adiposity balance, is superior to SMM% alone for predicting cardiac dysfunction. Our findings suggest that the relative balance, rather than absolute muscle mass, determines cardiac health in obesity, with implications for body composition assessment and intervention strategies. Full article

In situ observations of belowground tree–grass interactions are sparse in savanna ecosystems. In this study, we analyzed stable carbon and nitrogen isotopes (δ¹³C and δ¹⁵N) in soils and plants from four study sites in an African savanna ecosystem along the Kalahari moisture gradient. The homogeneous soil texture, primarily sandy soils, is well-drained and nutrient-poor, influencing vegetation and water retention uniformly across the region. At each site, soil samples were collected from a 120 cm deep soil profile. We used a 2-endmember mass balance approach to calculate the relative contributions of C₃ and C₄ plants to SOC in the 120 m soil profile. The wettest site was dominated by trees, whereas the driest site was dominated by shrubs. The intermediates had the highest amount of grass biomass. Our results revealed that tree- and shrub-derived SOC was highest in the wettest and driest sites, respectively. The contribution of C₃ plants was 63.8% and 55.8%, in the wettest and driest sites, respectively, when integrating the 120 cm depth. Grass-derived SOC was highest (69.4%) in the middle of the precipitation gradient when integrating the 120 cm depth. The δ¹⁵N values were highest in the middle of the precipitation gradient (10.7‰) and lowest in the wettest site (5.2‰). Our findings indicate that belowground tree–grass interactions and nitrogen cycling in savanna ecosystems are more complex than previously thought and do not conform to the traditional concept of the two-layer roots hypothesis. This lack of conformity could be attributed to several factors, including overlap in rooting depth and ecological drivers, such as wildfires and herbivory, which could stimulate production of belowground biomass. We used space-for-time substitution to leverage the region’s steep north–south precipitation gradient and homogeneous soil texture. Our results indicated that trees and shrubs would become an important SOC source in the two extreme sites of the transect, while grass would become an important SOC source in the middle of the precipitation gradient. Full article

Background/Objectives: This study evaluated the association between nutrient intake adequacy during early pregnancy and gestational diabetes mellitus (GDM) risk through a prospective cohort study of Korean pregnant women. Methods: A total of 2227 singleton pregnant women were included in this study. Dietary assessment was conducted once during early pregnancy enrollment using the 24 h dietary recall method. The collected dietary data were analyzed using the CAN-Pro Korean food composition database to calculate nutrient-specific intake levels. Nutrient Adequacy Ratio (NAR) for each nutrient and Mean Adequacy Ratio (MAR), which integrates individual NARs, were calculated based on intake levels. GDM diagnosis was determined using oral glucose tolerance test (OGTT) results conducted between 24 and 28 weeks of gestation. Relative risk (RR) for each individual nutrient was calculated, and logistic regression analysis was performed to estimate odds ratios (OR) for GDM risk according to MAR quartiles. Results: Among 2227 participants, 157 women developed GDM. Compared to the highest MAR quartile, women in the lowest quartile showed significantly increased GDM risk (OR = 1.82, 95% CI: 1.10–2.99), with the second lowest quartile demonstrating similarly elevated risk (OR = 1.75, 95% CI: 1.06–2.88). Among individual nutrients, inadequate vitamin D intake was associated with the highest GDM risk (RR = 3.84), followed by insufficient intakes of vitamin K (RR = 1.89), vitamin B₆ (RR = 1.62), niacin (RR = 1.54), and calcium (RR = 1.39). Body mass index-stratified analysis revealed that the association between low nutritional adequacy and GDM risk was particularly pronounced in women with BMI ≥ 25.0 kg/m², showing up to a four-fold increased risk in the lowest adequacy groups. Conclusions: These findings suggest that low overall dietary adequacy and nutritional imbalance during early pregnancy are associated with increased GDM risk. The results underscore the importance of ensuring adequate and balanced nutrition during early pregnancy for GDM prevention. Full article