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Calibration of three-strut macro model for solid masonry infill walls in reinforced concrete frames
No full textThis study presents a sensitivity analysis and calibration of solid infill walls, without openings, embedded in reinforced concrete frames, aiming to propose a simplified force–deformation model with a code-relevant three-strut macro modeling approach that reflects the best combination of its controlling parameters at inelastic drift levels. The sensitivity analysis considers the range of infill wall material properties as well as the lateral force–drift relationship parameters for the three-strut model. Experimental results obtained from available investigations are used to validate the numerical modeling and calibrate the parameters. The results demonstrate that the post-yield stiffness in the tri-linear material model and the tensile strength of the infill wall along the diagonal direction are the parameters governing the nonlinear response of infilled reinforced concrete frames. To better describe the behavior of infill walls without openings using the three-strut model, we propose a validated set of equations and calibrated parameters. The proposed modeling methodology provides a good match with experimental results and with the equivalent strut width formulas specified as in ASCE 41-23 FEMA273 and FEMA 356, but only when consistent lateral force–drift relationship parameters are applied
Injectable chitosan/maltodextrin/microcrystalline cellulose hydrogels loaded with melatonin for intervertebral disc regeneration
No full textIntervertebral discs have limited regenerative capacity despite their high susceptibility to age-related degeneration. Conventional treatments primarily manage symptoms and rarely restore function. Recent research focuses on injectable hydrogel systems for disc regeneration. In this study, an injectable melatonin-loaded hydrogel composed of chitosan (CS), oxidized maltodextrin (ox-MD), and oxidized microcrystalline cellulose (ox-MCC) was developed. Incorporation of MCC markedly reduced gelation time—from 33 s at the lowest concentration (0.125 %) to 12 s at the highest (0.5 %). At the highest MCC content, hydrogels also retained up to 75 % of their weights in degradation studies, compared with 40 % in MCC-free formulations. Increasing ox-MCC levels enhanced the mechanical properties, yielding approximately a six-fold increase in Young's modulus. Melatonin release reached 35.29 % from MCC-containing hydrogels and 26.65 % from hydrogels without MCC. Experiments with nucleus pulposus (NP) cells isolated from bovine vertebrae showed that all hydrogel groups were non-toxic, and melatonin-loaded hydrogels further supported cell proliferation. Moreover, all hydrogels significantly increased glycosaminoglycan synthesis by the cells by day 14, with the melatonin-loaded formulation showing the highest levels. Overall, melatonin-loaded hydrogels demonstrate strong potential for intervertebral disc regeneration
Snow cover mapping with Meteosat thir generation FCI: initial evaluation of the European Organisation for the Exploitation of Meteorological Satellites H SAF H43 snow mask product
No full textThis study presents the results of the initial validation of the EUMETSAT H SAF H43 snow cover product, the first operational snow product derived from the Flexible Combined Imager (FCI) onboard Meteosat Third Generation (MTG). The evaluation, covering the period from December 2024 to February 2025, includes a direct comparison with the earlier H34 product, generated from SEVIRI observations onboard Meteosat Second Generation (MSG). Analyses were conducted over three mountainous regions—the Alps, Turkey, and Georgia—using MODIS-based reference snow cover maps and in-situ snow-depth measurements from WMO synoptic stations. As snow cover in mountainous terrain plays a critical role in hydrology and water resources management, special attention was given to high-elevation zones (above 1,000 m), where snow is seasonally persistent and detection accuracy most relevant. The evaluation employed standard accuracy metrics—Probability of Detection (POD), False Alarm Ratio (FAR), and Overall Accuracy (ACC)—to assess performance across elevation, aspect, and land-cover classes. Results indicate that H43 provides consistent yet moderate improvements over H34, with miss-rate reductions of up to 40% above 2,000 m elevation and FAR values remaining below 30% across land-cover types. These improvements are supported by the enhanced radiometric performance and 10-min temporal resolution of the FCI sensor, which enable more effective cloud detection and frequent scene refresh. Combined with its near-real-time availability, these features make H43 a promising tool for operational snow monitoring, hydrological forecasting, and early-warning applications across topographically complex regions
Transitional separated flow over low-aspect-ratio NACA0012 wings
No full textThree-dimensional transitional separated flow over low-aspect-ratio NACA0012 wings (semi-aspect ratios of sAR = 1 and 2) is numerically investigated at Reynolds numbers of 1 × 104 and 4 × 104, across a range of angles of attack from 10° to 20°. The numerical simulations are performed by solving the unsteady Reynolds-averaged Navier-Stokes (URANS) equations, employing the transitional turbulence model of shear stress transport (SST) γ − Reθ to simulate the turbulent flow and predict the laminar-to-turbulent transition. It is observed that the lower aspect ratio wing (sAR = 1) produces lower lift and drag coefficients than the higher aspect ratio wing (sAR = 2), independent of the Reynolds number. For sAR = 1, the lift coefficient increases monotonically with angle of attack, whereas sAR = 2 exhibits the opposite trend at Re = 1 × 104. At lower aspect ratios, the downwash induced by the wingtip vortices affects a broader spanwise region. The spike in the sectional lift coefficient is found closer to the root for sAR = 1. Moreover, the separation and transition points are observed earlier for the higher aspect ratio wing. For sAR = 1, the wake remains steady under all tested conditions due to the strong downwash effect. This steady wake behaviour may be influenced by the turbulence modeling, which can suppress low-frequency vortex shedding compared to LES or DNS simulations. Whereas the unsteady flow and Karman vortex shedding appear across the midspan when the downwash weakens for sAR = 2
Larger crustacean zooplankton thrive at lower temperatures and under reduced predation in pond ecosystems
No full textBody size is a fundamental trait influencing ecological functions, trophic dynamics, and organismal fitness across ecosystems. However, the environmental drivers shaping body size patterns in pond ecosystems across broad spatial scales remain poorly defined. In this study, we assessed the main determinants of body size in cladocerans and copepods, key crustacean zooplankton groups, across 168 ponds including regions in Europe, Asia, and South America. We assess how temperature and latitudinal variation, food availability, and predation influence mean and maximum crustacean body sizes in zooplankton taxa. Using linear mixed models, we identified annual temperature and predation pressure as the strongest predictors of body sizes. Body size increased with lower temperature for both taxa, supporting the temperature-size rule. Fish presence was associated with smaller body sizes for both taxa, while copepod size metrics were additionally influenced by pond morphometry, showing a negative relationship with depth and a positive association with area. These findings suggest temperature and predation pressure act as major selective forces shaping crustacean body size in pond ecosystems. Understanding these patterns is essential for predicting how crustacean communities and processes they mediate may respond to ongoing climate warming, particularly in small-shallow freshwater ecosystems highly sensitive to environmental change
A novel finding on sex-dependent diverse behavioral responses to the anticipation of a threat in a rat model of fear conditioning with the involvement of brain-derived neurotrophic factor (BDNF) in the prefrontal cortex
No full textEvidence has shown significant sex differences in freezing and darting behaviors in a rat model of aversive learning using fear conditioning. The present study explored sex differences in a rat model of aversive learning using a fear-conditioning method via measuring freezing and darting behaviors. Fear conditioning was induced by three footshocks (0.8 mA, 3 s, 30-s interval) paired with an auditory conditioned stimulus (75 dB, 3 s). Extinction was performed by broadcasting 20 auditory conditioned stimuli (75 dB, 3 s, 30-s interval), with no shocks, in three, or four, of five sessions. Freezing and darting behaviors, locomotor activity and time spent in the center squares (anxiety-like behavior) in the open field test, and brain-derived neurotrophic factor (BDNF) in the infralimbic region of the mPFC (medial prefrontal cortex) were evaluated. The results showed both sexes showed a high rate of freezing, with males showing more freezing. Females were more responsive to extinction. Darting behavior was only observed in females and diminished following extinction. Locomotion and anxiety-like behavior were increased and decreased following extinction learning in both sexes, respectively. BDNF expression level in the infralimbic region of the mPFC was increased following extinction learning, with a greater increase in females. In conclusion, we showed that females have a diverse behavioral response to the anticipation of a threat in a rat model of fear conditioning. The important role of BDNF in the modulation of both freezing and darting behaviors was also shown
Electrochemical Performance of Al/Nb2O5//GO/Cu Asymmetric Hybrid Supercapacitors With Aqueous Potassium Hydroxide Electrolytes at Varying Concentrations
No full textAsymmetric hybrid supercapacitors integrating transition metal oxides with carbonaceous electrodes have attracted significant attention for advanced energy storage applications due to their ability to combine high energy density with rapid power delivery. In this study, an Al/Nb2O5 cathode and a Cu/graphene oxide (GO) anode were fabricated via slurry casting and electrophoretic deposition (EPD), respectively, and assembled with a paper separator in aqueous potassium hydroxide (KOH) electrolytes of varying concentrations (1, 2, and 3 M). Structural and morphological analyses confirmed the orthorhombic phase of Nb2O5 and the uniform deposition of GO films. Galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS) measurements revealed a strong dependence of electrochemical performance on electrolyte concentration. The device operating in 2 M KOH exhibited the most favorable balance between energy and power densities, achieving a specific capacitance of 30.7 F g−1, energy density of 36.5 Wh kg−1, and power density of 295 W kg−1, with a relaxation time constant of 0.634 ms. In contrast, 1 M KOH provided moderate energy storage capability, while 3 M KOH suffered from reduced capacitance due to increased viscosity and ion–ion interactions. Comparative analysis with literature data highlights the competitive performance of the Al/Nb2O5//Cu/GO configuration, particularly in terms of energy–power trade-off. These findings underscore the critical role of electrolyte optimization and electrode design in advancing hybrid supercapacitors for sustainable energy storage applications
Analysis and Design of Efficient Optically Transparent Antennas and Examples Realized with Silver Nanowires
No full textThe dilemma of optically transparent antennas, regardless of what material they are made from, has been the trade-off between transparency and antenna efficiency. This study examines the fundamental parameters that govern the two contradicting properties and presents optimized antenna designs for the two most basic antenna geometries: monopole and patch. For validation, monopoles and patches were fabricated using silver nanowires (AgNWs) that have a lower cost and an ease of preparation compared to transparent conductive oxides. The main reason for the gain reduction is Ohmic loss on the transparent conductor. Therefore, the gain improvement for the monopole antenna is to widen the geometry, and for the patch antenna, it is to raise the frequency, together with choosing an appropriate substrate. The gain is shown to be further enhanced by applying conductive strips at locations where the radiating current is concentrated, and by stacking transparent conductors. The two methods can be combined for further improvement. The prototyped AgNWs monopole antenna demonstrates a wide band operation from 3.5 GHz to 5.9 GHz, with an efficiency of 50.4% and an improvement to 76.3% with the addition of the conductive strips while keeping the optical transparency higher than 80%. The fully transparent patch antenna with both the patch and ground plane made of AgNWs is recorded to have a gain and efficiency of 3.58 dBi and 44% at 8.9 GHz. These designs outperform the existing studies in the transparency-gain trade-offs at relatively low frequency (<10 GHz), as most prior designs rely on raising the frequency to improve gain
