Search Results (3,761)

The influence of a non-resonant intense laser field on the optical absorption and Raman scattering processes in ZnO/Mg${}_{0.2}$Zn${}_{0.8}$O quantum wells is theoretically investigated. It is shown that the dressing field significantly modifies the confinement potential and reshapes the electronic wave functions, leading to tunable shifts in intersubband transition energies and changes in the dipole matrix elements. These laser-induced effects produce notable variations in the absorption spectrum and strongly modulate the Raman differential cross section and Raman gain. Under the application of a non-resonant laser field, the Raman gain is enhanced by almost a factor of four, whereas off-resonant pumping results in much weaker, yet still field-dependent, responses. The results demonstrate that intense laser fields provide an effective tool to dynamically control the optical and Raman properties of ZnO-based quantum well structures. Full article

Aluminum alloy tube–concrete composite columns have received increasing attention owing to their high strength-to-weight ratio and superior corrosion resistance compared with conventional steel–concrete composite columns. In this study, a refined finite element model is established to investigate the axial compression behavior of aluminum alloy tube–concrete long columns. The results indicate that the axial bearing capacity and deformation characteristics are strongly governed by the confinement effect provided by the aluminum alloy tube, which varies significantly with different cross-sectional configurations. Circular and square aluminum alloy tubes exhibit distinct confinement mechanisms, leading to different stress distributions and damage evolution patterns in the core concrete. Enhanced confinement effectively improves the utilization of concrete strength and delays local buckling of the aluminum alloy tube, thereby contributing to an increase in axial bearing capacity. Furthermore, parametric analyses clarify the combined influence of material properties and geometric parameters on the confinement efficiency and overall axial compression performance of the composite columns. Full article

Impure rock salt is increasingly used as a host medium for underground hydrogen and compressed air energy storage in China; however, its permeability evolution under stress remains insufficiently constrained. This study presents a systematic experimental and modeling investigation of the permeability behavior of impure rock salt from the Pingdingshan (Henan) and Yunying (Hubei) salt mines. Nineteen cylindrical specimens were subjected to full-process triaxial permeability testing, including initial measurements, hydrostatic damage recovery, and staged deviatoric loading. A hydrostatic recovery stage (15 h at 40 MPa) was applied to reduce coring- and machining-induced micro-damage, resulting in a permeability reduction in one to three orders of magnitude. After recovery, the initial permeability decreases nonlinearly with increasing effective stress and converges to approximately 10⁻²¹ m² at stress levels corresponding to in situ burial depths. During deviatoric loading, permeability exhibits a two-stage response: a rapid increase associated with early damage and microcrack initiation, followed by saturation once the dilatant volumetric strain exceeds approximately 1–2%. Impurity content influences both the magnitude and evolution of permeability by modifying the initial pore structure and damage development; however, the response is non-monotonic and region-dependent due to differences in dominant impurity mineralogy. Based on the experimental results, a semi-theoretical permeability model incorporating effective stress, dilatant strain, and impurity content was developed. The model reproduces the observed permeability evolution under different confining pressures with good agreement, providing a practical framework for evaluating the hydraulic integrity of impure rock salt in underground energy storage applications. Full article

To investigate the influence of a second-phase mineral on the rheology of mantle peridotite, we conducted high-temperature deformation experiments on dry olivine–clinopyroxene (Ol-Cpx) aggregates. Cylindrical samples were manufactured using hot-isostatic pressing techniques, with Ol as the matrix phase and Cpx added at volume fractions of f_Cpx = 0.1, 0.3, and 0.5. Deformation experiments were performed in a Paterson gas-medium apparatus at a confining pressure of ~300 MPa, temperatures ranging from 1423 to 1523 K, and strain rates of ~5 × 10⁻⁶ s⁻¹, ~1 × 10⁻⁵ s⁻¹, ~2 × 10⁻⁵ s⁻¹, and ~5 × 10⁻⁵ s⁻¹. The stress exponents (n = 3.4–4.3) for two-phase aggregates are comparable to those reported for both pure Ol and pure Cpx, indicating that dislocation creep remains the dominant deformation mechanism. Increasing Cpx content does not induce a transition of dominant mechanism but leads to a slight decrease in activation energy, consistent with predictions from two-phase rheological models and reflecting the increasing contribution of Cpx to bulk deformation. Normalized flow stresses fall between the Ol and Cpx end-members within the Taylor–Sachs bounds, indicating moderate strain partitioning between phases. Aggregates with f_Cpx = 0.5 show slightly reduced strength and lower effective stress exponents. This is attributed to enhanced dynamic recrystallization, which triggers grain-size reduction and thereby increases the contribution of diffusion-assisted deformation, even though dislocation creep remains the dominant mechanism. These results suggest that under dry conditions, Cpx primarily modulates the rheology of olivine-rich aggregates through microstructural evolution and strain partitioning rather than by altering the dominant deformation mechanism. Full article

Unmanned Aerial Vehicles (UAVs) have made significant advancements in communication stability and security through techniques such as frequency hopping, signal spreading, and adaptive interference suppression. However, challenges remain in modeling spectrum competition, integrating expert knowledge, and predicting opponent behavior. To address these issues, we propose UAV-FPG (Unmanned Aerial Vehicle–Frequency Point Game), a game-theoretic environment model that simulates the dynamic interaction between interference and anti-interference strategies of opponent and ally UAVs in communication frequency bands. The model incorporates a prior expert knowledge base to optimize frequency selection and employs large language models for episode-level opponent trajectory generation and planning within UAV-FPG, serving as an operationally more challenging simulator adversary for stress-testing anti-jamming policies under our evaluation protocol. Experimental results highlight the effectiveness of integrating the expert knowledge base and the large language model: relative to fixed-path baselines, iterative feedback-conditioned LLM planning tends to generate more adaptive trajectories and achieve higher opponent rewards in UAV-FPG. These findings are confined to the proposed simulation environment and are not intended as general claims about real-world jamming capability or onboard planning performance. UAV-FPG provides a robust platform for advancing anti-jamming strategies and intelligent decision-making in UAV communication systems. Full article

Background/Objectives: Low vaccination coverage and the persistence of zero-dose children remain the principal challenges for immunization efforts in Madagascar. To address these barriers, a socio-anthropological study was conducted to identify the determinants of both vaccination and non-vaccination in eight districts of the country. Methods: District selection was based primarily on immunization performance—specifically the proportion of zero-dose children—along with criteria of geographic and cultural diversity. A qualitative approach was employed, comprising 162 semi-structured individual interviews and 41 focus group discussions with key informants, including political–administrative, religious, and traditional authorities, healthcare workers, community health workers, and parents. Results: Overall, the benefits of vaccination were widely acknowledged by the population. Anti-vaccine rumors were found to be sporadic and, due to their provisional nature, potentially reversible even among those who relay them. Beyond conventional barriers such as scheduling constraints and limited accessibility, fluctuating motivation among community health workers and structural challenges affecting their work emerged as notable findings. Conversely, factors promoting vaccine acceptance were associated with trust in the vaccinators themselves and with a good understanding of vaccination-related issues, fostered through increased and context-specific sensitization efforts. Conclusions: In conclusion, no evidence was found to associate contexts such as rural settings or low-performing vaccination areas with lower vaccine acceptance. Similarly, anti-vaccine rumors were not confined to any particular category or group. Ultimately, the main obstacles are the prioritization of economic risk and concerns about potential side effects. The primary recommendation concerns strengthening awareness-raising efforts, while strengthening trust and improving the working conditions of community health workers. Full article

Fall-from-height fatalities in underground construction are closely associated with formwork scaffold operations, where dense steel members cause severe non-line-of-sight (NLOS) and multipath effects that degrade positioning performance. Although ultra-wideband (UWB) technology offers high theoretical ranging accuracy, its deployment-dependent performance in metal-rich scaffold environments remains insufficiently quantified. This study focuses on physical deployment optimization rather than algorithmic compensation. A full-scale formwork scaffold was constructed, and a stepwise one-factor controlled experimental design was employed to quantify the effects of anchor height (H) and horizontal spacing (S) on 3D positioning accuracy. The results show that sub-meter accuracy can be achieved through appropriate deployment, with a minimum 3D RMSE of 0.317 m and over 80% of single-axis errors confined within a 0.2 m engineering-valid region. For this specific setup, the optimal S = 1.5 m correlates with the scaffold grid size (approximately 0.8 times the 1.8 m bay width). While we hypothesize this ratio dependency applies to other geometries, this remains a site-specific observation requiring future cross-validation. Further analysis indicates that this deployment balances vertical signal visibility and multipath suppression. In addition, while the Position Dilution of Precision (PDOP) metric reflects geometric sensitivity, it does not linearly correlate with actual positioning errors under coplanar UWB deployments. These findings provide a rigorous static error model, serving as a critical prerequisite for developing robust real-time safety monitoring systems in scaffold-intensive construction environments. Full article

The accurate reconstruction of the internal temperature field in rotary kilns is critical for optimizing the clinker calcination process and ensuring energy efficiency. In this study, a rapid and high-fidelity surrogate modeling framework is proposed, utilizing snapshot ensembles generated by full-order Computational Fluid Dynamics (CFD) simulations to reconstruct the temperature field of the axial center section. The framework incorporates a symmetric Autoencoder (AE) coupled with a TabPFN network as its core components. Capitalizing on the kiln’s strong axial symmetry, this reduction–regression system efficiently maps the high-dimensional nonlinear thermodynamic topology of the central section into a compact low-dimensional latent manifold via AE, while utilizing TabPFN to establish a robust mapping between operating boundary conditions and these latent features. By leveraging the In-Context Learning (ICL) mechanism for prior-data fitting, TabPFN effectively overcomes the data scarcity inherent in high-cost CFD sampling. Predictive results demonstrate that the model achieves a coefficient of determination (R²) of 0.897 for latent feature regression, outperforming traditional algorithms by 6.53%. In terms of field reconstruction on the test set, the model yields an average temperature error of 15.31 K. Notably, 93.83% of the nodal errors are confined within a narrow range of 0–50 K, and the reconstructed distributions exhibit high consistency with the CFD benchmarks. Furthermore, compared to the hours required for full-scale simulations, the inference time is reduced to 0.45 s, representing a speedup of four orders of magnitude. Consequently, the predictive system demonstrates excellent accuracy and efficiency, serving as an effective substitute for traditional models to realize online monitoring and intelligent optimization. Full article

With the intensive development of urban underground space, excavations adjacent to existing tunnels have become increasingly common. This study investigates the response of adjacent tunnels and surrounding soil to multi-step foundation pit excavation and the effect and mechanism of a new capsule technology. Centrifuge model tests and finite element analysis were conducted for models both with and without a capsule. The results show that the soil deformation caused by each excavation step is confined to an influence zone. As the excavation deepens, this influence zone progressively expands. Excavation causes the tunnel to move outward and the retaining wall to rotate clockwise. The results demonstrate that capsule pressurization can effectively reduce the maximum horizontal displacement of the adjacent tunnel by approximately 30–40% compared to the case without reinforcement. Capsule pressurization alters the earth pressure distribution on the retaining wall and reduces tunnel displacement. The effect of the capsule decays with increasing distance from the capsule to the tunnel. The excavation impact propagates to the tunnel via wall–soil and soil–tunnel interactions. Capsule pressurization mitigates the tunnel response by ensuring that the surrounding soil experiences a smaller reduction in horizontal stress and exhibits a higher modulus during subsequent excavation. This enhanced state of the soil produces smaller deformation, which ultimately transfers less of the excavation effect to the tunnel and controls its displacement. The study concludes that the active pressure control offered by the capsule technology is a promising method for protecting existing tunnels during adjacent deep excavations. Full article

Waste tire rubber–soil mixtures feature low density, high energy dissipation, and low shear modulus, which are widely used in geotechnical engineering for vibration attenuation. In this study, the evolution of the small-strain stiffness characteristics of clay-rubber mixture (CRM) is investigated; a resonance column test was carried out to determine the small-strain stiffness characteristics of CRM samples with different confining pressures (${\sigma }_3$), rubber particle contents (${\mathrm{C}}_{\mathrm{rubber}}$), and rubber particle sizes (${\mathrm{D}}_{\mathrm{rubber}}$). The test results indicate that ${\sigma }_3$ can promote the dynamic shear modulus (G) of CRM and restrain the damping ratio (D). The rubber particles have a great influence on both G and D. Under the same conditions, G decreases significantly with the increase in ${\mathrm{C}}_{\mathrm{rubber}}$ and increases slightly with the increase in ${\mathrm{D}}_{\mathrm{rubber}}$, which indicates that rubber particles inhibit the development of G. D increases with the increase in ${\mathrm{C}}_{\mathrm{rubber}}$ and ${\mathrm{D}}_{\mathrm{rubber}}$. The results show that the contact area between clay particles and rubber particles increases with the increase in ${\mathrm{C}}_{\mathrm{rubber}}$, resulting in the decreases in G and D. The G–γ curves are analyzed by using the Hardin–Drnevich equation. Based on the fitting results, the maximum dynamic shear modulus ($G_{\max }$) is obtained. Therefore, the evolution of $G_{\max }$ with ${\sigma }_3$, ${\mathrm{C}}_{\mathrm{rubber}}$, and ${\mathrm{D}}_{\mathrm{rubber}}$ are analyzed, and an equation for the $G_{\max }$ of CRM considering the effects of ${\sigma }_3$, ${\mathrm{C}}_{\mathrm{rubber}}$, and ${\mathrm{D}}_{\mathrm{rubber}}$ is proposed. In addition, the D–γ curves can be well described by an empirical equation. Full article

High-water-content dredged slurry from port dredging requires geotechnical improvement via drainage and consolidation. The small-strain dynamic properties (shear stiffness, damping characteristics) of reconstituted and consolidated clays are critical to the dynamic response and serviceability of overlying infrastructure. This study uses resonant column tests to investigate how initial water content affects the small-strain dynamic behaviour of reconstituted Ningbo soft clay, focusing on the evolution of the dynamic shear modulus ($G$) and damping ratio ($\lambda$) under different initial water contents and confining pressures. The test results indicate that the initial water content exerts a pronounced effect on the maximum small-strain shear modulus ($G_{\mathrm{m}\mathrm{a}\mathrm{x}}$) and on the strain-dependent degradation pattern of $G$. $G_{\mathrm{m}\mathrm{a}\mathrm{x}}$ increases with decreasing water content, and confining pressure exerts a more pronounced enhancing effect on $G_{\mathrm{m}\mathrm{a}\mathrm{x}}$ under low water content conditions. For specimens with different initial water contents, the maximum shear modulus normalised by confining pressure $(G_{\mathrm{m}\mathrm{a}\mathrm{x}}/{({\sigma }_0^{\prime }/P_a)}^n)$ exhibits a consistent, material-specific functional relationship with void ratio ($e$) within the investigated ranges. By contrast, initial water content exerts limited effects on the normalised $G/G_{\mathrm{m}\mathrm{a}\mathrm{x}}-\gamma$ and $\lambda -\gamma$ curves in the tested small-strain range. On this basis, an empirical model for small-strain shear modulus incorporating initial water content effects is proposed to guide dynamic soil parameter selection for geotechnical design under the tested conditions. Full article

With the continuous advancement of the “dual-carbon” strategy, the penetration of renewable energy sources such as wind and photovoltaic (PV) power has steadily increased, imposing more stringent requirements on the safe and stable operation of modern power systems. As the core components of these systems, critical electrical devices operate under harsh conditions characterized by high voltage, strong electromagnetic interference (EMI), and confined high-temperature environments. Their operating status directly affects the reliability of the power supply, and any fault may trigger cascading failures, resulting in significant economic losses. To address the issues of low inspection efficiency, limited fault-identification accuracy, and unstable data transmission in strong-EMI environments, this study proposes an intelligent inspection system for power equipment based on multi-technology integration. The system incorporates a redundant dual-mode wireless transmission architecture combining Wireless Fidelity (Wi-Fi) and Fourth Generation (4G) cellular communication, ensuring reliable data transfer through adaptive link switching and anti-interference optimization. A You Only Look Once version 8 (YOLOv8) object-detection algorithm integrated with Open Source Computer Vision (OpenCV) techniques enables precise visual fault identification. Furthermore, a multi-source data-fusion strategy enhances diagnostic accuracy, while a dedicated monitoring scheme is developed for the water-cooling subsystem to simultaneously assess cooling performance and fault conditions. Experimental validation demonstrates that the proposed system achieves a fault-diagnosis accuracy exceeding 95.5%, effectively meeting the requirements of intelligent inspection in modern power systems and providing robust technical support for the operation and maintenance of critical electrical equipment. Full article

Aboveground storage tanks are used to store various fluids and chemicals for many industrial purposes. According to API standard 653, the structural integrity of these tanks must be regularly assessed. The U.S. EPA requires each operator to have a Spill Prevention, Control and Countermeasure Plan (SPCC) for aboveground storage containers. The accepted practice for inspection of these tanks, particularly the tank bottoms, requires removing the tank from service, emptying the tank, and interior entry for direct inspection of the structure. The required inspection operations are hazardous due to the chemicals themselves as well as the requirement to operate within confined spaces. An inspection from outside the tank would have significant cost and time benefits and would provide a large reduction in the risks faced by inspection personnel. Guided wave (GW) testing is a promising candidate for screening of storage tank walls and bottoms from the tank exterior due to the ability of GWs to propagate over long distances from a fixed probe location. The lowest-order transverse-motion guided wave modes (e.g., torsional vibrations in pipes) are a good choice for long-range inspection because this mode is not dispersive; therefore, the wave packets do not spread out in time. A common weakness of guided wave inspection is the complexity of report generation in the presence of multiple geometry features in the structure, such as welds, welded plate corners, attachments and so on. In some cases, these features cause generation of non-relevant indications caused by mode conversion. Another significant challenge in applying GW testing is development of probes with high-enough signal amplitudes and relatively small footprints to allow them to be mounted on short tank bottom extensions. In this paper, a new generation of magnetostrictive transducers will be presented. The transducers are based on the reversed Wiedemann effect and can generate shear horizontal mode guided waves over a wide frequency range (20–150 kHz) with SNRs in excess of 50 dB. The recently developed SwRI MST 8 × 8 probe contains an array of eight pairs of individual magnetostrictive transducers (MsTs). The data acquisition hardware allows acquisition using Full Matrix Capture (FMC) and analysis software reporting of anomalies based on Total Focusing Method (TFM) image reconstruction. This novel inspection package allows generation of reports that map out corrosion locations and provide estimates of defect widths. Case studies of this technology on actual storage tank walls and bottoms will be presented together with validation of processing methods on mockups with known anomalies and geometry features. Full article

With the increasing depletion of shallow resources, marine-based mineral resources in coastal and continental shelf areas are poised to become a new frontier for resource development. However, ions in brine solutions undergo complex water-rock interactions with rocks, affecting the engineering stability of marine-based rock masses. This study addresses engineering safety concerns arising from the long-term coupled effects of brine erosion and confining pressure on rocks during seabed mineral resource extraction. Using red sandstone as the research subject, it investigates the evolution of its mechanical properties under complex brine-erosion conditions. Experiments involved immersing red sandstone specimens in simulated seabed brine solutions for erosion cycles of 14, 21, and 35 days. Triaxial compression tests were conducted under confining pressures of 5 MPa, 10 MPa, and 15 MPa to systematically analyze the effects of erosion duration and confining pressure on rock strength, deformation, energy characteristics, and failure modes. Results indicate that brine erosion significantly reduces the strength and elastic modulus of red sandstone, but the effect is not simply linear. Instead, it follows a trend of initial slight strengthening followed by significant deterioration. During short-term erosion (21 days), some mechanical parameters slightly recovered, potentially due to temporary filling of fractures by brine ions. After long-term erosion (35 days), all mechanical properties markedly declined. This study aims to reveal the triaxial mechanical properties and energy evolution patterns of red sandstone under multi-ionic brine erosion, providing crucial experimental evidence for designing safe isolation layers and evaluating long-term stability in seabed mining. Full article

Recent and forthcoming bans on confinement systems for farmed animals highlight the growing societal and policy emphasis on improving welfare. In the United Kingdom, the proposed prohibition of enriched cages for laying hens represents a major step beyond existing European Union standards, reflecting both scientific evidence and public concern over the limitations of cage-based systems. While such reforms are indicative of farmed animal welfare gains domestically, experience from the EU ban on conventional cages indicates a critical policy gap: the absence of mechanisms to retire and decommission obsolete infrastructure allows housing systems to be resold or exported, potentially perpetuating welfare issues elsewhere. Similar patterns have emerged in pork production, where gestation and farrowing crates have been inconsistently phased out in different regions of the world, illustrating the broader consequences of neglecting infrastructure lifecycle management. This perspective is based on welfare reforms incorporating decommissioning of equipment to align ethical intent with material outcomes. Decommissioning approaches lead to incentivising or mandating the permanent removal of banned pork production physical infrastructure, mitigating economic risks for producers, and reducing cross-border exacerbation of welfare issues. Coordinated implementation across national, regional, and global locals is essential to maximise the pig welfare effectiveness of reforms. By integrating decommissioning provisions, policymakers can ensure that animal welfare improvements are substantive, credible, and globally effective. Full article