Nanopores on antennal chemosensilla in the fall armyworm, Spodoptera frugiperda.

Buried rigid box culverts are widely used in transportation and water structures and are often constructed beneath high embankments. Due to the stiffness contrast between the rigid structure and surrounding backfill soil, the soil column directly above the culvert experiences smaller settlement than adjacent soil columns, which may result in stress concentration and increased vertical pressure on the culvert. The induced trench installation (ITI) method was introduced to mitigate this problem by adopting a compressible inclusion above the structure to initiate positive soil arching and redistribute the loads away from the culvert. This study investigates the influence of expanded polystyrene (EPS) geofoam inclusion parameters on the structural behavior of buried rigid box culverts through a series of experimental tests. Eleven reduced-scale laboratory model tests were conducted, including one reference test without EPS and ten tests incorporating EPS inclusions with varying densities, thicknesses, widths, and installation locations. Static surface loading ranging from 20 to 140kPa was applied using a rigid footing system, while vertical pressures within the backfill were monitored using miniature pressure sensors installed above and beside the culvert. The results show that EPS inclusion significantly alters the load transfer mechanism within the backfill and promotes the development of positive soil arching. Among the investigated parameters, EPS thickness had the most pronounced influence on stress reduction, increasing the pressure reduction efficiency from approximately 50% to about 70% as the thickness increased from 2.5cm to 10cm. A lower EPS density also slightly enhanced stress reduction due to its higher compressibility. The findings demonstrate that properly configured EPS geofoam inclusions can effectively reduce vertical stresses acting on buried rigid culverts and improve their structural performance under embankment loading conditions.

Quasi-static investigations have demonstrated that continuous reinforcement traversing the columns enhances the load-bearing capacity of reinforced concrete (RC) flat slab systems subjected to progressive collapse initiated by column removal. Nevertheless, the dynamic behaviour of older structures lacking reinforcement remains insufficiently understood. To address this gap, high-fidelity numerical models were developed in LS-Dyna and validated against experimental data. In addition, the load redistribution and internal force transfer mechanisms were examined in this study. The results revealed that, following the removal of a central column, inertial effects amplified the applied load by a factor of 1.12, with more than 60% of the load ultimately redistributed to the edge columns. The influence of varying column removal scenarios and structural scales on the dynamic response and collapse resistance of flat slab systems was also explored. Findings indicate that the simultaneous loss of opposite edge columns imposes a greater collapse risk than the concurrent loss of adjacent edge columns. Moreover, the evaluation results of scaled RC flat slab structures tend to overestimate both their dynamic load-bearing capacity and punching shear resistance.

ABSTRACT The conventional decomposition method is widely adopted to evaluate the elastic buckling load of multi-story frames, in which each column is treated as an independent member with rotational spring supports at its two ends. The stiffness of these rotational springs is dependent on the adjacent beams and columns, which typically provide positive rotational stiffness. Nevertheless, when adjacent columns are slender or also prone to buckling, the significant negative rotational stiffness induced by these columns must be taken into account. This factor renders the decomposition method inappropriate. To overcome the limitations of traditional approaches, this study puts forward a novel limit method that incorporates parametric analysis. This integration not only simplifies the computational procedures but also improves the accuracy of elastic buckling load predictions. Furthermore, numerical investigations reveal that non-adjacent columns exert a negligible influence on the elastic buckling load of the critical column in a multi-story frame. Accordingly, a multi-story frame can generally be simplified into a three-column system composed of the critical column and its two adjacent columns. When the bottom column of the frame is the critical column, the multi-story frame can be further simplified into a dual-column system comprising only the bottom column and the second-floor column.

The Cairo Monorail System presents significant geotechnical challenges due to its integrated structural configuration and its alignment across heterogeneous soil conditions, including collapsible and swelling soils. This study investigates the foundation performance of the monorail through a combination of advanced site investigations, full-scale pile load testing under dry and wetted conditions, and finite-element modeling incorporating soil–structure interaction. Field load tests on large-diameter bored piles founded in collapsible soils demonstrated a pronounced increase in settlement and a reduction in stiffness following wetting, confirming the sensitivity of pile behavior to moisture variations. Three-dimensional numerical analyses of the integrated monorail system showed that differential settlements between adjacent columns are generally limited to less than 9 mm under serviceability loading conditions, satisfying passenger comfort requirements. Long-term coupled seepage–deformation analyses conducted using PLAXIS indicated that surface water infiltration into swelling soils may induce time-dependent monopile heave of approximately 10 mm over a 50-year design life, which remains within acceptable serviceability limits. The results demonstrate that detailed geotechnical characterization, combined with appropriate numerical modeling strategies, can effectively control differential deformation and long-term heave in continuous monorail systems, ensuring their operational safety and long-term performance.

We uncover a previously unreported solid-solid phase transition in tetrachloro-m-xylene (TCMX), a hexasubstituted benzene derivative exhibiting orientational disorder. Differential scanning calorimetry and powder x-ray diffraction reveal a weak but reproducible phase transition near 437K, corresponding to a continuous, second-order symmetry change from monoclinic P2_{1}/n (phase II) to orthorhombic Pnnm (phase I). Despite this structural reorganization, quasielastic neutron scattering demonstrates that molecular dynamics remain governed by discrete 60^{∘} in-plane reorientational jumps consistent with the pseudosixfold molecular symmetry. The activation energy is unaffected, while only slight variations in relaxation times and effective rotational radii are detected. Molecular dynamics simulations reproduce the transition and clarify its microscopic origin. In phase II, weak orientational correlations between adjacent molecular columns are present, but these constraints vanish in phase I, restoring higher symmetry without altering the underlying reorientational mechanism. This study establishes TCMX as a rare example of a disorder-disorder transition in which molecular dynamics are preserved while collective orientational correlations reorganize. More broadly, our results highlight how subtle symmetry changes govern emergent behavior in disordered crystals, advancing the understanding of plastic phases and phase transitions in complex condensed matter systems.

Effects of electromagnetic fields from an alternating current power cable on the embryogenesis of three benthic associated marine species.

Stage-specific nutrient pulses and transient microbial-network intensification in deep-water croaker cage aquaculture.

Secondary flows induced by spanwise heterogeneous surface roughness play a crucial role in determining engineering-relevant metrics such as surface drag, convective heat transfer and the transport of airborne scalars. While much of the existing literature has focused on idealized configurations with regularly spaced roughness elements, real-world surfaces often feature irregularities, clustering and topographic complexity for which the secondary flow response remains poorly understood. Motivated by this gap, we investigate multicolumn roughness configurations that serve as a regularized analogue of roughness clustering. Using large-eddy simulations, we systematically examine secondary flows across a controlled set of configurations in which cluster density and local arrangement are varied in an idealized manner, and observe that these variations give rise to distinct secondary flow polarities. Through a focused parameter study, we identify the spanwise gap between the edge-most roughness elements of adjacent columns, normalized by the channel half-height ( $s_a/H$ ), as a key geometric factor governing this polarity. In addition to analysing the time-averaged structure, we investigate how variations in polarity affect the instantaneous dynamics of secondary flows. Here, we find that the regions of high- and low-momentum fluid created by the secondary flows alternate in a chaotic, non-periodic manner over time. Further analysis of the vertical velocity signal shows that variability in vertical momentum transport is a persistent and intrinsic feature of secondary flow dynamics. Taken together, these findings provide a comprehensive picture of how the geometric arrangement of roughness elements governs both the mean structure and temporal behaviour of secondary flows.

How does the human brain resolve conflicts in sensory input to generate conscious perception? Using high-resolution 7 T functional MRI, we addressed this question by investigating column- and layer-specific activity in cortical and subcortical regions in humans during binocular rivalry. The results show that eye-specific rivalry arises from interocular inhibition between adjacent ocular dominance columns in the superficial layers of the primary visual cortex, but not between ocular layers of the lateral geniculate nucleus of the thalamus. Eye-specific feedback from the intraparietal sulcus plays an active role in biasing and synchronizing local competitions in the primary visual cortex into perceptually coherent representations, even without awareness of eye-of-origin information. These findings reveal the mesoscale mechanisms of perceptual conflict resolution in humans: local conflicts in sensory input are resolved by inhibitory microcircuits in the sensory cortex, while feedback signals from the parietal attention network bias and integrate local competitions into unified conscious perception.

Most design codes treat masonry infill walls as non - structural elements, and in the analysis of steel or reinforced concrete (RC) frame structures, their presence is often neglected. However, numerous studies have shown that infill walls significantly inf luence the strength, stiffness and ductility of the structure. Therefore, it is crucial to consider the contribution of infill walls to the building's behavior. Accurate modeling of the infill walls requires knowledge of the mechanical properties of masonry, various interacting parameters, and the contact conditions along the interface between the infill and the surrounding frame. Two prim ary techniques used in the analysis of infilled frame structures are macro - modeling and micro - modeling. Micro - modeling utilizes Finite Element (FE) software to represent the masonry panel as composed of many elements that simulate the bricks and mortar. In contrast, macro - modeling treats the masonry panel as a few elements, typically modeled as one or more compressive diagonal struts. Both techniques aim to capture the nonlinear behavior of the materials. The objective of this study is to assess the influence of the infill walls on the progressive collapse resistance of RC framed structures. To achieve this, an RC frame experimentally tested by Li et al. (2016) is modeled in Abaqus/Explicit software in two configurations: bare frame (without infill walls) an d infilled frame (with infill walls). The frame consists of four bays and two stories, and progressive collapse is triggered by the failure of the middle column from the first story. This failure is simulated through a step - by - step unloading process in a displacement - controlled manner. To evaluate the progressive collapse behavior of the two numerical models, nonlinear explicit dynamic analysis is adopted to simulate the quasi - static loading scheme. The Concrete Damaged Plasticity (CDP) model is used for both concrete and masonry , with the compressive stress - strain relationship following the Kent - Scott - Park constitutive model. The steel reinfor cement bars material properties are specified based on a bilinear stress - strain relationship. Tie - type connections are employed to model the interaction between the RC frame and masonry elements, while general contact is used to simulate th e interaction between masonry elements. The resistance force (applied vertical load) versus the vertical displacement of the middle column is monitored up to a displacement of 500 mm. The progressive collapse behavior of the frame is divided into four stages. The numerical results obtained for both models show good agreement with the experimental ones. It was found that during the first deformation phase (when adjacent and exterior columns moved outward), the infilled frame model resisted a vertical force approximately 4.8 times greater than the bare frame model. In conclusion, completely neglecting the infill walls in the progressive collapse analysis of RC framed structures leads to unrealistic results.

The loss of a load-bearing element, in a building can occur due to various factors and may trigger progressive collapse. The partial collapse of the Ronan Point Apartment in 1968 greatly increased awareness of progressive collapse, which is reflected in the growing number of related publications. This study investigates the progressive collapse behavior of multi-story buildings with and without slabs. In the models without slabs, the load that is expected to be transferred from the slabs to the beams was externally applied to the beams. Additionally, the study considers five different building heights, and evaluates the results based on UFC guidelines. More than 240 removal scenarios, covering six different locations on the building plan and varying story heights, were simulated using the ELS software. The results show that as the number of stories increases, displacements due to column removal generally decrease. Buildings designed to withstand seismic forces demonstrated efficient resistance to progressive collapse, with no significant plastic rotations observed, provided the slab contribution was included in the model. In contrast, models without slabs experienced collapse in all scenarios. This study highlights the importance of including slab contributions in simulations, as neglecting them can lead to inaccurate results. Furthermore, after the loss of a column, initial failure was often observed at the end of the top reinforcement in the beams connected to the removed column. By extending the length of the top reinforcement in the beams, the location of the initial failure shifts to the face of the adjacent column.

Settlement control for tunnel–terminal co-construction projects remains undefined, despite the growing trend of integrating multiple transportation modes within large-scale transport hubs. This study investigates a large underground structure passing beneath an airport terminal, combining field investigations, statistical analyses, and finite element simulations to examine differential settlement behavior under non-uniform loading conditions. The key contribution of this work is the proposal of a differential settlement control standard, defined by the tangent of the rotation angle between adjacent column foundations, with a recommended value of 1/625. Case analysis at cross-section E–E shows that the measured maximum tangent rotation angle was 1/839, corresponding to base slab settlements of 40.5 mm and 33.1 mm for the high-speed railway and metro structures, respectively. Application of the proposed 1/625 criterion yields allowable maximum base slab settlements of 55.28 mm for the high-speed railway and 44.83 mm for the metro, with differential settlement limits of 7.5 mm and 3.13 mm. Numerical simulations confirm the validity of this standard, ensuring the structural integrity of co-constructed systems and providing practical guidance for future airport terminal–tunnel integration projects.

Abstract The frame-core wall structure is one of the common forms of high-rise buildings. The progressive collapse characteristics of the structure are particularly important due to the local damage of the structure caused by accidental loads such as explosion and impact. A typical frame-core wall structure was selected, and the finite element analysis model was established through the explicit dynamic analysis software ANSYS/LS-DYNA to simulate and analyze the progressive collapse characteristics of the structure under local failure conditions. The results indicate that in a frame-core wall structure, partial destruction of the ground floor can lead to different collapse scenarios depending on the location of the failure. Specifically, failure of a corner shear wall is likely to trigger an overall collapse of the structure above the damaged area; failure of adjacent columns tends to cause a large-scale collapse on one side of the building; and extensive failure of the central core wall is prone to result in a vertical progressive collapse of the entire structure. In contrast, local damage occurring at the same horizontal level in the middle or upper parts of the structure generally does not lead to vertical progressive collapse.

This study addresses the issue of resistance plate deterioration in ultra-high voltage energy devices by proposing an improved symplectic geometric mode decomposition-wavelet packet (ISGMD-WP) algorithm that effectively extracts the component characteristics of leakage currents. The extracted features are subsequently input into the I-Informer network, allowing for the prediction of future trends and the provision of early short-term warnings. First, we enhance the symplectic geometric mode decomposition (SGMD) algorithm and introduce wavelet packet decomposition reconstruction before recombination, successfully isolating the prominent harmonics of leakage current. Second, we develop an advanced I-Informer prediction network featuring improvements in both the embedding and distillation layers to accurately forecast future changes in DC characteristics. Finally, leveraging the prediction results from multiple adjacent columns mitigates the impact of power grid fluctuations. By integrating these data with the deterioration interval, we can issue timely warnings regarding the condition of lightning arresters across each column. Experimental results demonstrate that the proposed ISGMD-WP effectively decomposes leakage current, achieving a decomposition ability evaluation index (EIDC) 1.95 under intense noise. Furthermore, in long-term prediction, the I-Informer network yields mean absolute error (MAE) and root mean square error (RMSE) indices of 0.02538 and 0.03175, respectively, enabling the accurate prediction of the energy device’s fault.

One of the new lateral force-resisting systems introduced to improve seismic performance of structures is the rocking buckling restrained braced frame (RBRBF). In this system, conventional braces and adjacent columns are designed to remain elastic until near seismic collapse. In this paper, RBRBFs are designed according to a displacement-based design approach. Maximum interstory drift ratio (MIDR) and maximum residual interstory drift ratio (MRIDR) are among the most critical engineering demand parameters (EDPs) used to assess the safety of structures after an earthquake. MIDR is the largest peak interstory drift ratio (IDR) observed among all the stories of a structure. The primary aim of this study is to investigate the effects of utilizing RBRBFs on MIDR and MRIDR responses compared with buckling restrained braced frames (BRBFs). For this purpose, 4-, 8-, and 12-story structures with the RBRBF and BRBF systems are considered, and their collapse capacity values and residual drift capacity values, given different levels of MRIDR, are computed using incremental dynamic analyses (IDAs). After computing the capacity values, the mean annual frequencies (MAFs) of collapse ([Formula: see text]) and exceeding different MRIDR levels ([Formula: see text] are obtained. The results demonstrate that all the RBRBFs have considerably better collapse and residual drift performance than the BRBFs. Based on these results, the use of RBRBF significantly reduces the weaknesses of BRBF including damage concentration in a single story and low post-yield stiffness. Cloud analyses are performed on the structures to investigate the height-wise distributions of peak floor accelerations (PFAs), peak IDRs, and residual interstory drift ratios (RIDRs). The results indicate that the RBRBFs have a uniform height-wise distribution of peak IDR, but the BRBFs have considerable peak IDR concentrations. Furthermore, the RBRBFs have much lower RIDRs than the BRBFs, whereas they experience higher PFAs than the BRBFs. Nevertheless, their PFAs, on average, are not significantly higher than those of the BRBFs.

With the improvement of building safety requirements and the need for risk assessment under extreme conditions such as earthquakes, fires, and explosions, research related to the failure of some key components has received more attention in recent years. The concrete frame is an important and complex research field in structural engineering when analyzing the chain reaction and collapse mode that may occur after the failure or removal of some columns. In order to study the influence of local damage on the stability of the residual structure of a typical frame concrete structure, the dynamic response and collapse resistance of the residual structure of a plane frame structure were analyzed by using the column removal method. Based on LS-DYNA, all working conditions of single column, double column, and multi-column in different demolition positions were designed. By studying the numerical simulation of different adjacent demolition columns and demolition positions, combined with force transmission path analysis and progressive collapse theory, the dynamic response process of damaged structures under different conditions was obtained. Based on the theory of resistance in progressive collapse, the collapse mode and response characteristics of plane frame structures were analyzed. Through the simulation verification of a multi-story frame structure, the dynamic response law under each column removal condition was obtained: with the increase in the number of columns removed, the collapse speed of the building structure and the dynamic response to the remaining structure are enhanced; as the failure column is closer to the center of the structure, the force transmission path of the surrounding structure becomes greater, the resistance provided by the structure increases, the collapse speed becomes slower, the dynamic response range increases, and the progressive collapse of the peripheral column is caused when multiple columns are removed. According to this law, the relationship between the location parameters of the failure column and the vertical displacement and horizontal displacement is established. The results show that the closer the multi-column collapse is to the central area of the structure, the greater the structural response caused by the failure column. Due to the greater constraints and force transmission paths closer to the remaining columns in the center of the structure, it is difficult for the failure structure to eventually cause collapse damage to the central members, and the failure of the secondary external columns close to the external area is more likely to lead to the progressive collapse of the edge structure. The research provides design ideas and insights for the anti-collapse design of frame structures under multi-column demolition conditions. Attention should be paid to the risk of progressive collapse caused by the sub-external area, and this part should be strengthened.

ABSTRACT Conventional DNA‐based encryption exhibits limited resistance against brute‐force attacks. To enhance image security, we propose an improved image encryption algorithm that integrates two‐dimensional chaotic mapping with optimized DNA encoding. First, a novel two‐dimensional chaotic mapping system is developed. The image is diagonally divided into upper and lower sections. The shorter columns are then systematically inserted into adjacent longer columns. A specialized linking mechanism first stretches the image into a linear sequence and then refolds it into a scrambled image that retains the original dimensions. Subsequently, DNA encoding is employed to induce pixel confusion and diffusion. The encryption key scrambles the original array, thereby enabling base substitution that generates an encoding lookup table. Following DNA‐based pixel encoding, lookup replacement and computational operations are executed prior to final decoding, which completes the encryption cycle. Experimental results confirm the algorithm's advantages, including an expansive key space, exceptional key sensitivity, efficient encryption performance, robust security, and practical implementation feasibility.

Steel plate shear walls are among the most promising lateral load-resisting systems. However, a major drawback of this system is that the thin steel plate infill is susceptible to buckling under its own weight or when exposed to seismic loads. To solve this problem, stiffeners are effectively employed. In this study, steel plate shear wall models incorporating perpendicular and horizontal cross-shaped and circular configurations were investigated. Finite element models of frame structures, comprising steel plate infill along with adjacent beams and columns, were developed in ANSYS and validated against experimental data from the scholarly literature. The numerical model demonstrated excellent agreement with published experimental results. After confirming model accuracy and material suitability, a series of 3-span, 5-story frame models, was generated to evaluate the effects of stiffener quantity (0, 2, 3, and 4) and configuration. To this end, pushover analyses were performed, and the resulting capacity curves were plotted. These curves were subsequently idealized following Federal Emergency Management Agency recommendations, and seismic parameters – including ductility factor, response modification factor, stiffness, and shear capacity – were thoroughly examined. In addition, cyclic loading analyses were performed by applying incremental displacements at the roof level, and the corresponding energy dissipation capacities were determined. The results indicate that steel plate shear walls with circular reinforcements exhibit a ductility factor of 29.41, whereas those with cross-shaped stiffeners have a ductility factor of 17.10, indicating the superior ductility performance of circular stiffeners. However, cross-shaped stiffeners outperform circular stiffeners in terms of shear capacity, reaching 5,815 kN compared to 4,020 kN. In addition, the highest stiffness value (921.5 kN/mm) was observed in the hybrid model incorporating both cross and circular stiffeners. Optimization analysis revealed that four perpendicular circular stiffeners yield the maximum energy dissipation capacity, while three circular stiffeners optimize ductility, response modification factor, and shear strength.

In view of the continuous collapse resistance of the remaining structure under impact column and side columns under vehicle loads, the composite plane frame of concrete filled steel tubes (CFST) was established by using the finite element software ABAQUS, and the orthogonal experimental design and analysis were carried out. Through numerical analysis, the whole process of continuous collapse of the structure caused by low-speed impact is simulated. The research results show that: in the collapse mechanism of the two working conditions, the deformation modes of the impact column and the remaining frame show two modes. According to the fact that the axial force of the adjacent bottom column of the non-impact column increases greatly at first and then tends to be stable after being impacted, the axial force of the non-adjacent bottom column fluctuates up and down around the impact front axle force. Comparing the two working conditions with the direct simulation method (DS) and the alternate path method (AP), the reliability of AP method in evaluating the internal force of the remaining structure under impact load is insufficient, and it is unsafe to judge the collapse degree of the structure. According to the result of range analysis, it can be seen that the velocity is the most important factor to cause the dynamic effect of the remaining structure in the two cases. This study deeply analyzes the influence of the structural damage caused by the low-speed impact of accidents on the continuous collapse of the remaining structures, which has very important theoretical and practical significance for improving the anti-continuous collapse ability of buildings.