Search Results (162)

Bed-separation grouting filling mining is a damage-mitigation mining technology characterized by non-interfering mining and filling operations, low cost, and high efficiency. To recover coal resources from the 3801 working face located beneath a surface gas station in a Shanxi coal mine, this study first analyzed the maximum allowable deformation values for the gas station’s canopy, business hall, and oil storage tanks. Second, the feasibility and safety of bed-separation grouting filling mining at the 3801 working face were investigated using physical similarity modeling and the probability integral method. Finally, a field application of this technology was carried out at the 3801 working face. The results show that: (1) After the successive mining of the 3802, 3803 and 3801 working faces, the No. 17 bed separation was finally preserved above the 3801 working face. It is located in the upper part of the water-conducting fracture zone and has a thick impermeable isolation layer. (2) Physical similarity simulation and numerical simulation (3UDEC) of bed-separation grouting filling mining at the 3801 working face indicate that the underlying strata are effectively compacted after mining, and both overlying strata movement and surface subsidence above the grouting zone are significantly reduced. (3) The probability integral method was adopted to predict surface movement and deformation induced by mining at the 3801 working face (bed-separation grouting filling mining), the 3802 working face (fully mechanized top-coal caving mining) and the 3803 working face (full-seam mining in a single lift). All surface movement and deformation indices satisfy the surface deformation control requirements for the gas station. (4) After completion of the overburden bed-separation grouting filling project at the 3801 working face, the measured surface movement and deformation values during and after mining are all below the allowable deformation limits. No large deformations or cracks occurred in gas station structures including the canopy, business hall and oil tank farm. The protection effect is satisfactory, and the gas station has maintained normal operation throughout the mining period. Full article

With the steady progress of the global energy transition and the pursuit of “dual carbon” goals, Offshore Carbon Sequestration (OCS) has emerged as a pivotal strategic pathway within Carbon Capture and Storage (CCS) initiatives aimed at mitigating climate warming. Nevertheless, the drilling of OCS injection wells faces severe challenges, including narrow geological pressure windows, high risks of shallow geohazards, stringent environmental protection standards, and prohibitive construction costs. Riserless Mud Recovery (RMR) technology, as a novel and eco-friendly deepwater drilling technique, provides innovative technical support for OCS by establishing a closed-loop seafloor circulation system that achieves dual-gradient pressure control and “near-zero discharge” of drilling fluids. This paper systematically reviews the development history and technical principles of RMR. By integrating the specific requirements of OCS injection well drilling—such as wellbore integrity, environmental protection, and shallow hazard mitigation—the study provides an in-depth analysis of the application potential of RMR in drilling CO₂ injection wells within shallow formations. Furthermore, it demonstrates the engineering feasibility of RMR across technical, environmental, and economic dimensions. Building on this analysis, the paper discusses current technical challenges regarding key equipment research and development, adaptability to complex operating conditions, enhancement of intelligent control systems, and the establishment of technical standards. It also outlines the prospects for the integrated development of RMR with emerging fields, including hydrate-based carbon sequestration, intelligent drilling and completion, and carbon sequestration in far-reaching deep-sea areas. The research indicates that RMR technology can effectively resolve the dual constraints of cost control and environmental protection in OCS drilling. With breakthroughs in critical hardware, such as high-displacement subsea lift pumps, and the deepening of cross-disciplinary integration, RMR is poised to become an essential technical pillar in the field of offshore carbon sequestration. Full article

Emergency responders face a high risk of musculoskeletal disorders (MSDs), particularly lower back injuries, due to frequent patient-handling tasks performed in awkward and dynamic postures. This aim of study is to utilize dual motion capture systems integrated with a digital human modeling (DHM) ergonomics tool to evaluate the biomechanical effects of two common two-person carrying techniques: facing forward and facing each other. Twenty-two participants lifted a 25 kg mannequin while wearing Xsens motion sensors, and lumbar forces and joint angles were analyzed using Siemens Jack software (v9.0). Peak compressive and anterior–posterior (AP) shear forces, along with trunk, hip, and knee joint angles, were examined. Compressive forces ranged from approximately 948.6 to 2955.6 N, and AP shear forces ranged from 286.0 to 827.0 N. Mean compressive and AP shear forces were higher during the facing-each-other task (1977.3 N and 595.0 N) than during the facing-forward task (1596.0 N and 462.0 N). Males experienced higher spinal loads than females across both tasks. The facing-each-other technique was associated with greater hip flexion, lower knee flexion, and reduced trunk flexion, whereas the facing-forward technique resulted in less hip flexion, greater knee flexion, and greater trunk flexion. Overall, under the conditions of the present study, the facing-forward technique was associated with lower lumbar loading indicators. Integrating motion capture with DHM offers a valuable approach for evaluating realistic rescue tasks and can inform ergonomic training strategies for emergency responders. Full article

Active flow control represents a key enabling technology for advancing aerodynamic performance, offering significant potential improvements in drag reduction, lift enhancement, and overall efficiency. This paper reviews state-of-the-art active flow control techniques originally developed for aerospace applications and evaluates their applicability to automotive systems, considering constraints such as packaging, efficiency, cost, and integration. A structured classification of fluidic, surface-based (including morphing), and plasma-based approaches is presented, followed by a comparative and decision-oriented assessment of their performance, technological maturity, and feasibility. The results indicate that synthetic jet actuators and morphing-based solutions provide the most balanced compromise between aerodynamic effectiveness and practical implementation. In contrast, conventional fluidic methods are limited by low system efficiency, while plasma-based techniques, although highly responsive, face challenges related to scalability and integration. Full article

In rural South Africa, many households lack access to clean and reliable water sources and are therefore forced to rely on contaminated sources for their daily needs. This study presents the design of a manually operated hand water pump with an integrated filtration system. The design makes use of a double-acting cylinder and is optimized for a 50 m static lift, as this depth provides an optimal balance between structural integrity and ergonomic limits. SolidWorks Flow Simulations 2020 and numerical analysis show that the system overcomes a dynamic head of 51.44 m and a pump pressure of 503,063.62 Pa while maintaining a mechanical advantage of 4.8. Through the use of anthropometric data, a crank radius of 0.396 m was deemed optimal, resulting in a peak hand force of 158.38 N. This design proves that deep well water extraction can be achieved without any compromise to user ergonomics. By integrating filtration, unlike existing designs, this pump offers a practical solution for the water challenges faced in rural communities. Full article

Magnetically driven microrobots operating in intestinal environments face two major challenges: difficulty in traversing low-height confined spaces and limited local visibility caused by mucosal obstruction. To address these issues, this study proposes a gradient-field-based force-driven control method for a mudskipper-inspired magnetic microrobot. By establishing the mapping among coil current, magnetic field, and magnetic force at the robot working point, and by solving the control input through singular value decomposition and linear programming, effective magnetic-force output along a desired direction was achieved. On this basis, two representative force-driven motions were designed. The first was a translational mode based on pulsed magnetic-force actuation for stable navigation in low-height confined spaces. The second was a lifting mode based on continuous loading and gradual adjustment of the magnetic-force upper bound to locally lift a flexible “mucosa-like” membrane, thereby simulating intestinal mucosal elevation and local visual field expansion. Experimental results showed that the robot could stably pass through narrow tunnels and effectively lift an overlying flexible membrane under vertical magnetic-force actuation. The proposed method extends both the locomotion capability and the local interaction capability of the mudskipper-inspired magnetic microrobot, and demonstrates a feasible proof-of-concept approach for confined-space navigation and localized manipulation in intestinal applications. Full article

3D bird pose estimation plays a pivotal role in ecological conservation research. However, it remains a formidable challenge due to extensive joint deformation, severe self-occlusion, and the scarcity of 3D ground truth data. Therefore, practical solutions typically rely on accurate 2D keypoint detection from monocular images and subsequent 3D lifting. Although the High-Resolution Network (HRNet) has established a benchmark in 2D pose estimation by preserving high-resolution feature representations, its architecture, which relies on small convolution kernels, faces difficulties in capturing the global long-range dependencies necessary to resolve severe occlusions. To address these deficiencies, the core contributions of this work are summarized as follows: (1) We design a Gated LS-Block with a partial channel gating strategy to decouple channel mixing from spatial mixing, and extract global long-range dependencies via the proposed Large–Small Convolution (LSConv) to minimize feature redundancy. (2) We embed this block into Stage 2 of HRNet, enhancing multi-scale feature learning while slightly reducing model parameters and computational overhead; (3) To alleviate the ill-posed nature of monocular 3D lifting without paired supervision, we develop an unsupervised 3D reconstruction algorithm. Experimental results on the Animal Kingdom dataset demonstrate that our method achieves a 0.9% improvement in PCK@0.05 while reducing GFLOPs by 3.3%. These results verify that the proposed architecture enhances the model’s representation capability for bird poses while ensuring efficient inference. Meanwhile, we validate the applicability of the proposed 3D reconstruction algorithm via qualitative experiments, and further demonstrate that our unsupervised 3D lifting algorithm successfully preserves low symmetry error and robust bone length consistency with proxy metrics. Full article

The paper presents Nicholas of Cusa’s position in the debate on mystical theology, which had a place around the middle of the 15th century in monastic environments. His contribution to that debate was presented in the form of the treatise entitled On the Vision of God, complemented by a painted representation of the “All-seeing Face”. Both the treatise and the painting were designed to be aids in an experiment projected by Cusanus for his benedictine friends of Tegernsee Abbey, to help them in their progress towards mystical contemplation. The intention was to show them a way to lift their thought from the perception of the image, through meditation and prayer, to the contemplation of God. Thus, both the icon and his treatise were intended to fulfil an anagogical function for the users in inspiring them start on a journey of returning to God and teaching them how to effect that return. Besides giving an account of the experiment projected by Cusanus, the most important elements of his fascinating system are delineated, such as the way of mystical ascent, his use of paradox, his conception of God as the Infinity, and the conception of God’s seeing as the foundation of the existence of all things. Full article

The multirotor configuration unmanned aerial vehicle faces a significant challenge in simultaneously achieving long-range operation and high payload capacity. This paper investigates the power management strategy for a novel fuel–electric hybrid aircraft that incorporates lifting wings to reduce rotor load and a range-extend system to enhance energy supply. An equivalent consumption minimization strategy is developed to optimize, in real time, the power distribution between the internal combustion engine and the battery. The primary innovation of this paper lies in the application and rigorous validation of the equivalent consumption minimization strategy on this new aircraft configuration, which effectively minimizes total energy cost by optimally balancing fuel consumption and battery degradation, resulting in significantly reduced fuel usage and a more stable power output compared to conventional approaches. Full article

Increasingly frequent extreme rainfall commonly leads to water accumulation on the road surface, elevating vehicle tire hydroplaning to a major threat to driving safety. Existing research mainly focused on tire model optimization or predicting critical hydroplaning speed features based on empirical formulas and numerical simulations. However, there is a lack of systematic validation of the tire–water–pavement coupling interaction under realistic pavement conditions, with particular insufficient attention paid to pavement dynamic responses. In this study, numerical simulation and field full-scale accelerated loading methods were applied to investigate dynamic response characteristics of the tire–water–pavement coupling interaction system. Parametric analyses were first performed to investigate the influences of vehicle speed, vehicle load, water-film thickness, and tire lateral position on the mechanical behaviors of the fluid–structure interaction for a moving vehicle tire. Subsequently, field-measured dynamic responses’ features were used to validate the numerical model, which was then further applied to predict critical conditions of vehicle tire hydroplaning. Finally, the mechanisms of hydroplaning and corresponding mitigation measures were discussed. The study revealed that increasing vehicle speed and water-film thickness, as well as decreasing vehicle load, would reduce the pavement supporting force. The tire–pavement contact stress and strain decreased from the vehicle tire’s center position towards its shoulders. The predicted critical hydroplaning condition suggested that increasing vehicle load mitigated hydroplaning by reducing the proportion of water-induced hydrodynamic lifting force relative to the total vehicle load. When the water depth is relatively shallow, the hydroplaning risk increases rapidly with water depth, while the water’s adverse impact on tire–pavement contact force gradually diminishes as water depth continues to increase. It implies that a vehicle with a relatively low axle load driving on the pavement with a thin thickness of retained water in light rain will still face the hydroplaning risk, as the pavement’s supporting force may be substantially reduced in this weather. The findings provide theoretical foundations and experimentally supported insights on driving safety assessment and anti-skid design of water-covered pavement. Full article

Introduction: Facial aging is characterized by progressive soft-tissue descent, affecting all anatomical layers—from bone structures to the skin envelope. Early manifestations include downward displacement of the midface soft tissues, deepening of the nasolacrimal and nasolabial folds, and the appearance of soft-tissue “puckering” in the lower third of the face. At this stage, patients typically seek aesthetic correction to restore youthful facial contours with minimal or no visible signs of surgical intervention. Methods: This study is an observational analysis of a prospectively maintained surgical database including 201 female patients who underwent TESL between 2006 and 2024. Patient demographic data, surgical technique specifics, and postoperative outcomes were collected. A total of 612 procedures were performed. The cohort was stratified into two age groups: 30–35 years (n = 72) and 36–45 years (n = 129). Results: No cases of facial nerve injury or neurological complications were observed. Complications included 13 cases of localized cicatricial alopecia (6.47%) and four postoperative hematomas (1.99%). Eleven patients (5.47%) required minor secondary revision to address preauricular skin pleating. The technique demonstrated consistent and favorable outcomes in restoring soft-tissue volume and positioning, eliminating early lower-face “puckering,” and improving the cervicomental and mandibular contours. Conclusions: For patients under 45 years of age presenting with early signs of facial soft-tissue ptosis, endoscopic subcutaneous midface elevation with vertical SMAS plication is a safe, effective, and minimally invasive approach to rejuvenating the mid and lower face. Full article

The Yingxian Wooden Pagoda, a structure with a history spanning a thousand years, currently faces significant wind-induced safety risks. To understand the aerodynamic mechanism behind this issue, this study uses Computational Fluid Dynamics (CFD) with the Realizable k-ε turbulence model to perform high-fidelity transient simulations at wind speeds from 10 to 30 m per second. The results show that the highest positive pressure occurs on the sides of the windward face, while a large low-pressure vortex zone forms on the leeward side. The simulations include both the Kármán vortex street and the measurement of three-dimensional vortex-induced forces, marking a major advancement. A key finding is the synchronized period (ratio ≈ 1) of the along-wind and cross-wind forces, which differs from streamlined cylinders and is due to the pagoda’s unique octagonal shape. The force amplitudes increase exponentially with wind speed, while the average drag and lift have a quadratic relationship. Additionally, a new shape-specific correction factor of 0.875 is introduced to adjust the classical Strouhal formula, which greatly improves prediction accuracy for this type of ancient structure. This study offers both a theoretical foundation and a practical “digital wind tunnel” method for assessing wind-induced risks and supporting the safety monitoring of historic timber structures. Full article

Background/Objectives: To describe a previously unreported compensatory behavior used by an infant with severe bilateral congenital ptosis associated with blepharophimosis syndrome (BPES). Methods: Observational case report of a 4.5-month-old infant with severe bilateral congenital upper eyelid ptosis due to BPES. Results: The infant demonstrated classic compensatory mechanisms, including frontalis overaction and chin elevation, which were insufficient to clear the visual axis. Notably, she repeatedly used the dorsal surfaces of both fists to elevate the upper eyelids simultaneously and maintain fixation on faces. This behavior ceased following bilateral frontalis suspension surgery with silicone rods. Conclusions: In early infancy, severe bilateral ptosis may prompt the emergence of alternative, developmentally constrained compensatory behaviors. The bilateral fist lid-lift appears to represent a visually driven, sensorimotor strategy to clear the visual axis when conventional mechanisms are ineffective. Recognition of this behavior expands understanding of early compensatory responses in congenital ptosis and BPES. Full article

Airframe noise generated at wing trailing edges and high-lift devices, such as flaps, remains a major challenge during landing, with significant contributions in the low-frequency band of 500–1500 Hz. While solid surfaces reflect this acoustic energy, metallic porous materials can effectively absorb it through viscous and thermal dissipation within their internal pore structure. To address this, the present study examines the acoustic absorption characteristics of open-cell AlSi porous cylinders featuring controlled pore diameters between 0.3 mm and 2.25 mm. Measurements were conducted in an acoustic impedance tube according to the ISO 10534-2:2023 standard, using six cylindrical samples (28 mm diameter, 70 mm length). Two sets of measurements were performed for each sample (front and rear faces), and the average values were used. The findings indicate that the normal-incidence sound absorption coefficient α rises as pore size increases, reaching 0.93–0.97 at low frequencies of 500–700 Hz for the samples with the largest pores (1.8–2.25 mm). These results indicate that open-cell AlSi alloys offer strong low-frequencies sound absorption, positioning them as promising options for aeroacoustic noise mitigation, including applications such as porous trailing edge and hybrid flap designs. Full article

This study addresses critical safety and productivity challenges faced by tower crane operators due to limited visibility during lifting operations. An intelligent crane-mounted visual system was implemented to enhance operator visibility, reduce communication faults, and improve overall crane performance in high-rise construction. The study followed a five-stage methodology: a literature review of visual and sensor technologies for collision prevention, site visits to identify visibility challenges, a comparative analysis of cranes with and without the vision system, and an impact assessment on safety and quality. The crane-mounted video system significantly improved efficiency, safety, and work quality, reducing cycle time, defined as the duration from hook pickup to placement, by 25%, with this reduction statistically significant at p < 0.001 using a two-paired t-test. Fewer near-miss incidents and lower idle times for workers and operators were observed, even when a less experienced operator operated the system. A cost–benefit assessment indicates that crane vision systems can generate annual economic benefits exceeding 240,000 NIS through accident prevention and time savings, based on the project context. This study’s contribution lies in providing a comprehensive, real-world evaluation of retrofitting older cranes with advanced vision technologies, demonstrating measurable impacts on safety, productivity, and economic outcomes. Full article