Search Results (119)

Spodoptera frugiperda (fall armyworm, FAW) has rapidly spread across Asia and Africa in recent years, with its seasonal long-distance migration ability serving as the biological basis driving its region-wide outbreaks. Although the migratory biology of FAW has been extensively studied, it remains unclear whether there is stable differentiation between migratory and non-migratory individuals. In this study, we revealed the significant differences in morphological parameters between migratory populations and laboratory-reared populations. The migratory populations exhibited a greater body length and width and forewing size, as well as a lower body weight, compared to the laboratory colony. After three generations of indoor rearing, the migrants’ morphology and flight capacity converged to the laboratory phenotype, indicating the existence of a migratory ecotype in FAW. Through further investigation, a method for identifying the migratory ecotype of FAW was proposed based on the corrected wing loading (WL) and forewing aspect ratio (FA), which was successfully applied to distinguish individuals of the migratory ecotype in field populations. Our results confirm that FAWs exhibit stable differentiation into a migratory ecotype, and using WL and FA provides a robust, field-deployable tool for regional FAW monitoring, early warning systems, and targeted FAW control. Full article

Maritime remote sensing ship detection has long been plagued by two major issues: the failure of geometric priors due to the extreme length-to-width ratio of ships; and the sharp drop in edge signal-to-noise ratio caused by the overlapping chromaticity domain between ships and seawater, which leads to unsatisfactory accuracy of existing detectors in such scenarios. Therefore, this paper proposes an optical remote sensing ship detection model combining channel shuffling and bilinear interpolation, named CSBI-YOLO. The core innovations include three aspects: First, a group shuffling feature enhancement module is designed, embedding parallel group bottlenecks and channel shuffling mechanisms into the interface between the YOLOv8 backbone and neck to achieve multi-scale semantic information coupling with a small number of parameters. Second, an edge-gated upsampling unit is constructed, using separable Sobel magnitude as structural prior and a learnable gating mechanism to suppress low-contrast noise on the sea surface. Third, an R-IoU-Focal loss function is proposed, introducing logarithmic curvature penalty and adaptive weights to achieve joint optimization in three dimensions: location, shape, and scale. Dual validation was conducted on the self-built SlewSea-RS dataset and the public DOTA-ship dataset. The results show that on the SlewSea-RS dataset, the mAP₅₀ and mAP_50–95 values of the CSBI-YOLO model increased by 6% and 5.4%, respectively. On the DOTA-ship dataset, comparisons with various models demonstrate that the proposed model outperforms others, proving the excellent performance of the CSBI-YOLO model in detecting maritime ship targets. Full article

Global warming and urban expansion impose far-reaching, negative implications on the quality of the outdoor thermal environment in residential areas. Due to its potential for microclimate regulation and easy configuration with less site restrictions, the transitional space is an effective mitigation measure to transform existing outdoor spaces for thermal discomfort. The point of this article is to explore the optimum design parameters of the transitional space for increasing outdoor thermal comfort, with a focus on its orientation, aspect ratio (H/W), plan aspect ratio (L/W), and enclosure degree. The ENVI-met micro-meteorological model is adopted to visualize the environmental parameters after field measurement whereas the Ecotect is applied to validate the thermal performance under different design variants. The simulation results show that the thermal performance of geometry and orientation for the transitional space is seasonally discordant. On account of giving consideration to balance the double demands of solar shading in summer and solar gain in winter, a south-oriented transitional space with the windward side enclosure, length-width ratio of 2:1, and aspect ratio with 1.2 produces a greater thermal environment in Tianjin, China. Combined with the previous literature, south-oriented transitional spaces have a comparative advantage in balancing year-round thermal comfort for most cases; the deviation of the preferred orientation in the corresponding cities from the due south orientation is within 90° of a counterclockwise rotation. The lower aspect ratio (approximately below 1), deeper shape, and lower enclosure of the transitional spaces is appropriate for tropical and subtropical areas to avoid excessive sunshine; for temperate climates with hot summers and cold winters, such as in Tianjin, the reverse happens. Full article

In this numerical and experimental study, the effects of the width, length, and height parameters of a mirror arm on the drag coefficients of two side-view mirror models were investigated. The analyses were performed according to fractional factorial Taguchi L9 experiment plans. In the wind tunnel, a constant-temperature hot-wire anemometer and a pressure scanner system were used to measure velocity and static pressures, respectively. A realizable k-ε turbulence model with a scalable wall function was applied in the simulations, and the velocity was kept constant at 30 m/s. Means of the drag coefficient, signal/noise values, and analysis of variance were used to evaluate the parameters’ effects. The results showed that the drag coefficients increased with arm height. The increase in arm width decreased the drag coefficient to a limited extent, while the aspect ratio (width/height) showed a strong negative correlation with the drag coefficient. The high aspect ratios resulted in streamlined geometries around the mirror arm and delayed flow separations. The numerical analysis results showed good agreement with the experimental values for both mirror models. Full article

Silicon carbide (SiC) is a promising semiconductor material for electronics and photonics. Ultrafast laser processing of SiC enables three-dimensional nanostructuring, enriching and expanding the functionalities of SiC devices. However, challenges arise in delivering uniform, high-aspect-ratio (length-to-width) nanostructures due to difficulties in confining light energy at the nanoscale while simultaneously regulating intense photo modifications. In this study, we report the controllable growth of long-distance, high-straightness, and high-parallelism multifilament structures in SiC using ultrafast laser processing. The mechanism is the formation of femtosecond multifilaments through the nonlinear effects of clamping equilibrium, which allow highly confined light to propagate without diffraction in parallel channels, further inducing high-aspect-ratio nanostripe-like photomodifications. By employing an elliptical Gaussian beam—rather than a circular one—and optimizing pulse durations to stabilize multifilaments with regular positional distributions, the induced multifilament structures can reach a length of approximately 90 μm with a minimum linewidth of only 28 nm, resulting in an aspect ratio of over 3200:1. Raman tests indicate that the photomodified regions consist of amorphous SiC, amorphous silicon, and amorphous carbon, and photoluminescence tests reveal that silicon vacancy color centers could be induced in areas with lower light power density. By leveraging femtosecond multifilaments for diffraction-less light confinement, this work proposes an effective method for manufacturing deep-subwavelength, high-aspect-ratio nanostructures in SiC. Full article

Spores offer the most accessible diagnostic characters for the early-divergent Lycopodiaceae. We quantified eight morphometric traits—equivalent diameter, polar length, equatorial width, projected area, perimeter, and aspect ratio—in a balanced sample of 50 spores from each of six Central European taxa (Diphasiastrum alpinum, D. tristachyum, D. complanatum, Lycopodium annotinum, L. clavatum, and Huperzia selago) collected in the Białowieża Primeval Forest. Integrated light-microscope and scanning-electron-microscope imaging revealed three discrete wall-ornamentation syndromes (reticulate, verrucate, and granulose) that parallel the quantitative gradients. Principal component analysis showed that a single, collinear size axis accounts for 79% of variance, situating H. selago at the large-diameter extreme (mean: $37\mathsf{\mu }\mathrm{m}$) and the three Diphasiastrum species at the small-diameter pole (mean: 32–$33\mathsf{\mu }\mathrm{m}$). One-way ANOVA ($p<{10}^{-31}$) and PERMANOVA ($R^2=0.52$) confirmed decisive interspecific separation that mirrors published molecular phylogenies, underscoring a strong phylogenetic signal in spore form. While trait baselines are taxonomically stable, moderate microhabitat-driven shifts indicate limited ecophenotypic plasticity. The resulting high-resolution benchmark refines palynological identification, enables rapid spore-based bioindication of demographic stress, and strengthens conservation monitoring in relic temperate forest ecosystems. Full article

Grout propagation is a critical aspect of fracture grouting. This study investigated grout propagation at fracture intersections under flowing conditions using a simplified two-dimensional (2D) fracture network. Transparent soil technology was employed to simulate the porous filling material within the fractures. The results showed that the penetration velocity of grout decreased significantly after passing through an intersection, and the velocity in the main fracture was consistently higher than that in the branch fractures. In the unfilled fracture network, the diffusion ratio between branch and main fractures ranged from 0.35 to 0.88, whereas after filling, it ranged from 0.71 to 0.86. For each intersection, the ratio of grout length in the downstream branch to that in the main fracture (RDM) was positively correlated with branch width. This trend was especially evident in unfilled fractures, whereas in filled fractures, the increase in RDM was much less pronounced. Regarding the upstream ratio (RUM), it was consistently lower than RDM. RUM increased with branch width in unfilled fractures but decreased in filled fractures. Additionally, higher fluid velocity amplified these anisotropic propagation behaviors. Based on the simplified filled fracture model, it was concluded that porous filling materials reduce permeability differences between fractures with different aperture widths. Furthermore, increased flow rate intensified the anisotropic diffusion of grout. This study provides valuable insight into the mechanism of anisotropic grout propagation and offers guidance for engineering grouting applications. Full article

The corrosion of high-strength steel wires is a key factor impacting the durability and reliability of cable-stayed bridges. In this study, the corrosion pit features on a high-strength steel wire, which had been in service for 27 years, were extracted and modeled using three-dimensional point cloud data obtained through 3D surface scanning. The Otsu method was applied for image binarization, and each corrosion pit was geometrically represented as an ellipse. Key pit parameters—including length, width, depth, aspect ratio, and a defect parameter—were statistically analyzed. Results of the Kolmogorov–Smirnov (K–S) test at a 95% confidence level indicated that the directional angle component (θ) did not conform to any known probability distribution. In contrast, the pit width (b) and defect parameter (Φ) followed a generalized extreme value distribution, the aspect ratio (b/a) matched a Beta distribution, and both the pit length (a) and depth (d) were best described by a Gaussian mixture model. The obtained results provide valuable reference for assessing the stress state, in-service performance, and predicted remaining service life of operational stay cables. Full article

Numerous dark linear recurrent features called Recurring Slope Lineae (RSL) are observed on Martian surfaces, hypothesized as footprints of high-salinity liquid flow. This paper experimentally examined this “wet hypothesis” by analyzing the aspect ratios (length/width) of the flow traces on the granular material column to investigate how they vary with the granular material column, liquid and its flow rate, and inclination. While pure water produced low aspect ratios (<1.0) on the Martian regolith simulant column, high-salinity fluid (CaCl₂(aq)) traces exhibited significantly higher aspect ratios (>4.0), suggesting that pure water alone is insufficient to explain RSL formulation. Furthermore, the aspect ratios of high-salinity fluid traces on Martian regolith simulants were among the highest observed across all studied granular materials with similar particle sizes, aligning closely with actual RSL observed on Martian slopes. The results further suggest that variable ARs of actual RSL at the given slope can partly be explained by variable flow rates of high-salinity flow as well as salinity (i.e., viscosity) of flow. The results can be attributed to the unique granular properties of Martian regolith, characterized by the lowest permeability and Beavers–Joseph slip coefficient among the studied granular materials. This distinctive microstructure surface promotes surface flow over Darcy flow within the regolith column, leading to a narrow and long-distance feature with high aspect ratios observed in Martian RSL. Thus, our findings support that high-salinity flows are the primary driver behind RSL formation on Mars. Our study suggests the presence of salts on the Martian surface and paves the way for further investigation into RSL formulation processes. Full article

The most common size measurements for agricultural produce, including fruits and vegetables, are length and width. While the length of any agricultural produce can be unique, the width varies continuously along its length. Single-width measurements alone are insufficient for accurately characterizing varying width profiles, resulting in an inaccurate representation of the shape or mean dimension. Consequently, the manual measurement of multiple mean dimensions is laborious or impractical, and no information in this domain is available. Therefore, an efficient alternative computer vision measurement tool was developed utilizing ImageJ (Ver. 1.54p). Twenty sample sets, comprising fruits and vegetables, with each representing different shapes, were selected and measured for length and multiple widths. A statistically significant minimum number of multiple widths was determined for practical measurements based on an object’s shape. The “aspect ratio” (width/length) was identified to serve as an effective indicator of the minimum multiple width measurements. In general, 50 multiple width measurements are recommended; however, even 15 measurements would be satisfactory ($\mathrm{1.0\%}\pm \mathrm{0.6\%}$ deviation from 50 widths). The developed plugin was fast (734 ms ± 365 ms CPU time/image), accurate (>99.6%), and cost-effective, and it incorporated several user-friendly and helpful features. This study’s outcomes have practical applications in the characterization, quality control, grading and sorting, and pricing determination of agricultural produce. Full article

In the present study, a programme of experimental investigations was carried out to examine the direct uniaxial tensile (and pull-out) behaviour of plain and fibre-reinforced lightweight aggregate concrete. The lightweight aggregates were recycled from fly ash waste, also known as Pulverised Fuel Ash (PFA), which is a by-product of coal-fired electricity power stations. Steel fibres were used with different aspect ratios and hooked ends with single, double and triple bends corresponding to 3D, 4D and 5D types of DRAMIX steel fibres, respectively. Key parameters such as the concrete compressive strength f_lck, fibre volume fraction V_f, number of bends n_b, embedded length L_E and inclination angle ϴ_f were considered. The fibres were added at volume fractions V_f of 1% and 2% to cover the practical range, and a direct tensile test was carried out using a purpose-built pull-out test developed as part of the present study. Thus, the tensile mechanical properties were established, and a generic constitutive tensile stress–crack width σ-ω model for both plain and fibrous lightweight concrete was created and validated against experimental data from the present study and from previous research found in the literature (including RILEM uniaxial tests) involving different types of lightweight aggregates, concrete strengths and steel fibres. It was concluded that the higher the number of bends n_b and the higher the volume fraction V_f and concrete strength f_lck, the stronger the fibre–matrix interfacial bond and thus the more pronounced the enhancement provided by the fibres to the uniaxial tensile residual strength and ductility in the form of work and fracture energy. A fibre optimisation study was also carried out, and design recommendations are provided. Full article

Exploring host preference and resource partitioning among seed predator species is essential for understanding the coexistence mechanisms and guiding effective forest pest management. This study aimed to elucidate how seed traits influence infestation dynamics and species interactions, focusing on acorn weevils infesting Quercus mongolica. Species identification and clarification of their evolutionary relationships within the Curculio genus were performed through phylogenetic analyses of the mitochondrial cytochrome c oxidase subunit I gene sequences. The seed infestation patterns were assessed by comparing the infestation rates across various seed size classes. Furthermore, the correlations between the seed morphological traits (length, width, aspect ratio, and weight) and weevil abundance were analyzed. The phylogenetic results revealed well-supported monophyletic clades corresponding to Curculio arakawai and Curculio sikkimensis. This confirmed the clear genetic separation between these two distinct weevil species, thereby substantiating the divergence observed in weevil populations correlated with different seed hosts. The infestation patterns revealed the association of weevil species-specific preferences with seed size: C. arakawai predominantly infested larger acorn seeds, whereas C. sikkimensis predominantly infested smaller acorn seeds. C. sikkimensis favored smaller ones. Both species exhibited positive correlations between abundance and seed length and width in larger seeds; however, the seed weight displayed no significant effect. These results indicate niche differentiation mediated by seed size and morphology, which likely reduced interspecific competition and facilitated coexistence. This study elucidates species-specific host selection patterns in acorn weevils and highlights acorn traits as crucial factors shaping seed predator assemblages. The findings provide valuable insights for developing targeted pest management strategies and supporting sustainable oak forest regeneration. Full article

To achieve efficient preparation of microfine tool electrodes with a large aspect ratio, a bipolar pulse vertical liquid membrane electrochemical etching technique was proposed. The difference in current density distribution on the surface of tungsten rods under single-ended and double-ended vertical liquid membrane methods was analyzed using COMSOL software. The effects of negative voltage and pulse width on the distribution of electrolytic products and electrode preparation were investigated. It was found that when a large number of hydrogen bubbles were generated on the surface of the electrode, the electrode lost the protection of the diffusion layer, and the length was drastically shortened. When the pulse width was large, the electrode surface was covered with a coating layer of insoluble electrolysis product, and the shortening of electrode length was suppressed. Subsequently, the effects of forward voltage and bias on electrode preparation were investigated for large pulse widths. The optimal parameters are as follows: electrolyte concentration of 0.5 M, forward voltage of 4 V, negative voltage of −2 V, pulse period of 50 microseconds, and pulse width of 40 microseconds. Finally, the tool electrode with an average diameter of about 23.8 μm and an aspect ratio of 91.2 was prepared. Full article

During the natural growth of trees, a large number of branches are formed, with a negative impact on timber quality. Therefore, pruning is an essential measure in forest cultivation. In this work, the effect of pruning on poplar timber quality was evaluated. This study used an artificial forest of Populus deltoides “Nanlin 3804”, established in 2014, as the research object. Pruning was carried out in March 2018 and March 2020 with a pruning intensity of one-third, and a control group was also set up. In December 2023, the growth of 11-year-old poplars under different treatments was investigated and analyzed, and sample trees were cut down for a wood property analysis. The results showed that pruning did not have a significant effect on the growth of the diameter at breast height, the tree height, or the volume. However, pruning could significantly facilitate the forming of higher-quality timber with smaller knots. Compared to unpruned wood, the ring width decreased 1–2 years after pruning, while it turned out to be greater than that of the control 3 years after pruning. Moreover, pruning can reduce the degree of trunk tapering. The fiber aspect ratio two years after pruning was greater than that of the control. The distribution frequency of fiber lengths of between 1500 μm and 1900 μm and that of fiber widths of between 32 μm and 38 μm were higher than that of the control. However, pruning had little effect on their density and oven-dried shrinkage. In addition, compared to the control, the bending strength and the modulus of elasticity increased by approximately 11%–14%, the impact toughness decreased by approximately 5%, and the compressive strength increased by approximately 6%. Pruning proved to be a successful method to improve the timber quality. Full article

Clay soils are known to have a high swelling pressure with an increase in water content. This behavior is considered a serious hazard to structures built upon them. Various mechanical and chemical treatments have historically been used to stabilize the swelling behavior of clay soils. This work investigates the potential use of shredded plastic waste to reduce the swelling pressure and compressibility of clay soils. Two types of highly plastic clay (CH) soils were selected. Three different dimensions of plastic waste pieces were used, namely lengths of 0.5 cm, 1.0 cm, and 1.5 cm, with a width of 1 mm. A blend of plastic–cement waste with a ratio of 1:5 by weight was prepared. Different fractions of the plastic–cement waste blend with a 2 wt.% increment were added to the clay soil, which was then remolded in a consolidometer ring at 95% relative compaction and 3.0% below the optimum. The zero swell test, as per ASTM D4546, was conducted on the remolded soil samples after three curing periods: 1, 2, and 7 days. This method ensures the accurate evaluation of swell potential and stabilization efficiency over time. The experimental results showed that the addition of 6.0–8.0% of the blend significantly reduced the swelling pressure, demonstrating the mixture’s effectiveness in soil stabilization. It also reduced the swell potential of the expansive clay soil and had a substantial effect on the reduction in its compressibility, especially with a higher aspect ratio. The compression index decreased, while the maximum past pressure increased with a higher plastic–cement ratio. The 7-day curing time is the optimum time to stabilize expansive clay soils with the plastic–cement waste mixture. This study provides strong evidence that plastic waste can enhance soil mechanical properties, making it a viable geotechnical solution. Full article