Search Results (2,834)

Small-scale excavations with depths of approximately 1 to 3 m are widely conducted for purposes such as the repair of underground pipelines. In confined construction spaces, earth-retaining systems consisting of lightweight sheet-piles with struts and walers are frequently used. However, comprehensive investigations of the influence of ground conditions on member forces have not yet been conducted. Furthermore, since these temporary structures are generally not designed with seismic considerations, they may suffer damage during earthquakes depending on the soil conditions. Accordingly, this study conducted a comprehensive parametric numerical investigation to evaluate how differences in soil type, such as sandy and cohesive soils, and loading conditions during excavation and earthquake loading affect the internal forces in the supporting members. Excavation analyses using PLAXIS 3D confirmed that as the soil strength parameters (cohesion and internal friction angle) decreased, the demand on the supporting members increased and larger internal forces developed. Dynamic analyses using LIQCA 3D revealed complex behavior in which (i) earth pressure acting on the wall generated compressive forces in the struts, (ii) lateral deformation of the excavation face reduced axial forces in the struts, and (iii) when the ground liquefied, it exhibited a vibration-isolation effect, and the vibration components generated in the structural members became smaller. Full article

Orf virus (ORFV) is a major pathogen in goats and sheep, and control currently depends mainly on commercial live vaccines. Although mRNA vaccines have revolutionized human medicine, their use in veterinary settings is largely unexplored. In this study, an mRNA vaccine candidate encoding the ORFV F1L protein (F1L-mRNA-LNP) was developed via in vitro transcription and encapsulated in lipid nanoparticles. BALB/c mice were divided into five groups (n = 14 each): three receiving different doses of F1L-mRNA-LNP (5, 10, or 15 μg), one receiving a commercial live vaccine (CV), and a PBS control group. Mice were immunized intramuscularly and boosted after 14 days; immune responses were assessed 14 days later following ARRIVE 2.0 guidelines. Both the F1L-mRNA-LNP and CV vaccines induced specific antibodies versus PBS (p < 0.01). The 10 μg mRNA group showed Th1 cytokine and CD8⁺ T cell responses comparable to CV (p > 0.05), whereas IL-4 (Th2) was significantly higher in the CV group (p < 0.05). Neutralizing antibody titers did not differ between groups, indicating that the mRNA vaccine induces comparable Th1 cellular immunity but weaker Th2 humoral immunity. Upon ORFV challenge, the 10 μg F1L-mRNA-LNP vaccine protected BALB/c mice, as evidenced by stable body weight, no clinical symptoms, and reduced viral load, with efficacy comparable to CV (p > 0.05). This study provides strong evidence supporting the optimization of ORFV mRNA vaccines and highlights the translational potential of the F1L-mRNA-LNP candidate vaccine for veterinary applications. Full article

This study examines the strongly nonlinear cross-media dynamics of a deep-sea umbilical cable–payload system during free-surface crossing under different sea states and lifting speeds. A two-dimensional time-domain lumped-mass model was established, in which the cable was discretized into node–axial elements. Morison-type hydrodynamic loading, added mass, and a continuous air–water parameter transition governed by an immersion factor were included for both the cable and the lower-end payload. To improve numerical robustness in long-duration simulations, a segmented ODE15s integration scheme was adopted, together with a smooth-start lifting–heave boundary condition and an adaptive lift-height correction procedure to ensure a stable cross-media response window. The results show a clear spatially segmented response: the upper cable remains nearly straight, whereas the middle and lower sections accommodate most of the lateral offset and curvature redistribution, which intensify under stronger environmental forcing. Top tension shows a gradually increasing mean component superimposed on quasi-periodic oscillations, while bottom tension, detrended vertical payload displacement, and vertical hydrodynamic force are more sensitive to sea-state severity and lifting speed. These results provide a comparative numerical basis for identifying response trends, screening lifting speed options, and interpreting cross-media load transfer mechanisms. Because the formulation is two-dimensional and has not yet been validated against model-scale or full-scale measurements, the results should not be interpreted as equipment-specific safety limits. Full article

Plate–monopile hybrid foundations, as a potential alternative to monopiles, have demonstrated promising potential in enhancing load-bearing capacity and structural stability. To investigate its load transfer mechanisms and pile–soil interaction in clay, numerical models are developed under varying undrained shear strength (Su), pile diameter (D), and plate-to-pile diameter ratio (R). Through comparative analyses within different parameters configurations, the load-bearing capacity, pile deflection, bending moment and shear force distributions are systematically examined. The results indicate that: (1) Su, D and R are all positively correlated with the load-bearing capacity of the hybrid foundation, which can be expressed as the superposition of the monopile capacity and a quadratic function of R; (2) with increasing R, load transfer shifts from deep to shallow soil, accompanied by an upward pivot shift; increasing D causes a downward shift, more pronounced in weak soils; (3) for small-diameter hybrid foundation, the bending moment decreases progressively with increasing R, while for large-diameter, a stage-dependent response is observed, characterised by local moment concentration near the mudline within a certain range of R; (4) the shear force exhibits a double-peak pattern; increasing R strengthens the shallow peak and weakens the deep one, while increasing D localises the distribution near the mudline. Full article

Floating offshore wind turbines (FOWTs) have become an important structural configuration for deep-water offshore wind energy development. However, existing studies have mainly focused on towing experience for conventional offshore structures and static stability assessment, while a systematic understanding of the multi-body coupled dynamic response characteristics and hazardous response factors of large-scale FOWTs under combined wind, wave, and current loads remains limited. To address the insufficient understanding of critical hazardous response indicators in existing studies, a 10 MW semi-submersible floating wind turbine was investigated in this study. Variations in environmental loads, towline constraints, and FOWT responses during towing were incorporated into a multi-body coupled analysis framework, and the key hazardous response indicators governed by different dominant environmental factors were identified. The results indicate that increasing wind speed significantly amplifies the pitch response, with the extreme pitch angle reaching approximately −7.17° under the 24 m/s wind condition. Variations in current velocity have limited influence on response amplitudes. Wave height has the most pronounced effect on heave motion and nacelle acceleration. Under the 6.5 m wave height condition, their extreme values reach approximately −1.37 m and 1.15 m/s², respectively. Under the single-tug towing configuration, the 45° and 90° environmental directions induce pronounced lateral and yaw offsets, indicating insufficient path-keeping capability under unfavorable environmental directions. Comprehensive analysis demonstrates that pitch motion should be regarded as the primary hazardous response indicator under high wind speed conditions, while nacelle acceleration and heave motion require particular attention under high wave height conditions. Full article

Background: The aim of this study was to analyze the success of dental implants in patients with functional diversity by comparing success rates and marginal bone loss with those observed in patients without functional diversity, with both groups being subjected to a strict implant maintenance and hygiene protocol. Methods: A retrospective observational case–control study was designed. Two main study groups were established: one comprising patients with functional diversity (case group) and another including patients without functional diversity (control group), all of whom had received dental implants. Implant success rates were evaluated 12 months after prosthetic loading. Marginal bone loss was quantified according to the classification proposed by Lagervall and Jansson, later modified and validated by Corcuera-Flores et al. In addition, the Silness and Löe plaque index, presence of bruxism, implant characteristics, and rehabilitation techniques were recorded at each follow-up visit. Results: A total of 63 dental implants were placed in 20 patients included in the present study. The case group consisted of 9 patients who received 31 implants, whereas the control group comprised 11 patients who received 32 implants. No statistically significant differences were observed between groups in terms of implant success and MBL. Oral hygiene was assessed showed a statistically significant difference between groups (p = 0.001). Significant differences were also found regarding bruxism prevalence between groups, which was higher in the case group. Conclusions: The results obtained in the present study indicate that implant therapy in patients with functional diversity can achieve success rates comparable to those observed in patients without disabilities despite the higher prevalence of bruxism and a greater amount of dental plaque. These findings reinforce the importance of individualized treatment planning, adequate oral hygiene control, and periodic clinical follow-up in order to ensure long-term implant stability and peri-implant health. Full article

Polyurethane-solidified ballast (PSB) technology and geogrid reinforcement can be used to strengthen ballast beds. However, there has been little research on the mechanical properties of ballast beds under the combined effects of these two methods. This study addresses this research gap through an integrated experimental–numerical investigation of the cooperative reinforcement mechanisms. Uniaxial compression and oblique shear tests were conducted on standard and geogrid-reinforced PSB specimens, and a three-dimensional random aggregate finite element model was developed to represent the actual ballast gradation. The results show that geogrid reinforcement increased the compressive strength by 42.1% and reduced the maximum lateral deformation by 14.2%, while having little influence on the elastic modulus and Poisson’s ratio. In the oblique shear tests, geogrid reinforcement increased the peak loads by 14.2–23.0% compared with the standard specimen. A directional dependence was also observed, with the highest peak load occurring when the shear plane corresponded to the unreinforced surface. These findings clarify the cooperative reinforcement mechanism between polyurethane solidification and geogrid confinement and provide a mechanical basis for designing reinforced ballasted trackbeds in heavy-haul railways subjected to high axle loads and pronounced lateral deformation, as well as in high-speed railway lines requiring enhanced track stability. Full article

Background and Objectives: Exoskeletons may be useful in preventing musculoskeletal disorders. This study aimed to evaluate the biomechanical and subjective effects of a passive shoulder exoskeleton during overhead assembly work in a real-world automotive manufacturing environment. Materials and Methods: Sixteen workers performing overhead assembly tasks participated in this study. Muscle activity, joint angles, and joint reaction forces were compared between the No Exo and Exo conditions during overhead work. Muscle activity was measured using surface electromyography (EMG), upper-body kinematics were captured using inertial measurement units (IMUs), and shoulder joint torques and reaction forces were estimated using the AnyBody musculoskeletal modeling system. Additionally, user satisfaction was assessed through a questionnaire. Results: Comparison of biomechanical outcomes between the No Exo and Exo conditions showed that the Exo condition significantly reduced anterior and lateral deltoid activities by approximately 15.2% and 11.1%, respectively, and reduced glenohumeral joint reaction force by 115.24 N (all p < 0.05). Participants also reported lower physical workload (p < 0.001). Conclusions: The study results suggest that wearing an exoskeleton during overhead work may reduce shoulder muscle loading and improve biomechanical indicators associated with shoulder loading. Full article

Crack detection in composite structures remains a central challenge in structural health monitoring, particularly when sensing must rely on a small number of embedded multiplexed fiber Bragg gratings (FBGs). Here, we present a physics-guided convolutional neural network (CNN) framework for crack-associated event detection from multiplexed FBG interrogator signals acquired during the three-point bending of glass-fiber-reinforced polymer (GFRP) beams. The dataset was constructed from raw interrogator recordings and synchronized force–displacement metadata while preserving the cracked and non-cracked loading stages present in the experiments. Each candidate response was encoded by 13 synchronized optical, loading, and mechanics-guided descriptors, including Euler–Bernoulli expected strain and residual terms, where the residual denotes the difference between the measured response and the elastic response predicted by beam theory. A compact one-dimensional CNN operating on 30-response sequences was evaluated on 64 experimental runs under strict leave-one-run-out validation. At the selected operating point, the model reached window-level precision of 0.900, recall of 0.910, F1 score of 0.905, and balanced accuracy of 0.942, while the corresponding run-level decision reached a precision of 0.833, a recall of 1.000, an F1 score of 0.909, and a balanced accuracy of 0.969. Bootstrap resampling over runs yielded 95% confidence intervals of 0.787–0.978 for window-level F1 and 0.769–1.000 for run-level F1. To probe generalization beyond the initial fabrication batch, the final frozen pipeline was also tested once on seven later-batch runs from two newly manufactured specimens, where it reached a window-level precision of 0.908, a recall of 1.000, an F1 score of 0.952, a balanced accuracy of 0.969, an ROC-AUC of 0.979, a PR-AUC of 0.955, and perfect run-level classification. These results show that a compact sequence CNN, enriched with mechanics-guided strain interpretation, can extract robust crack-event signatures from multiplexed FBG measurements while preserving a simple and reproducible modeling pipeline. Full article

Seabed scour-induced degradation of the pile–soil system, together with the coupled action of seismic, wind and wave loads, poses great challenges to the long-term service safety of jacket-type offshore wind turbines. In this study, an integrated structural numerical model is established with consideration of nonlinear pile–soil interaction. By coupling OpenFAST (Version 3.5.0) and OpenSees (Version 3.7.0), accurate wind and wave load generation and refined calculation of structural dynamic responses are achieved. Then, the dynamic performance of jacket-type offshore wind turbines under combined wind–wave–seismic loads is analyzed at different scour depths (0D, 1D, 2D and 3D, where D is the pile diameter). Structural response characteristics before and after seismic excitation are emphatically compared under two typical sea states: collinear wind–wave condition (COD-2.2) and non-collinear wind–wave condition (MIS-2.4). The results show that seismic excitation substantially amplifies structural dynamic responses. Meanwhile, strong seismic interference weakens the influence of wind–wave directionality to a certain degree, lowering the response difference between the COD-2.2 and MIS-2.4 cases. It is further found that scour depth remains the dominant factor controlling pile internal forces and foundation lateral deformation even when seismic effects are incorporated. Moreover, under the selected Chi-Chi ground motion, scour aggravation markedly increases the seismic response amplification and internal force concentration of the structure. This research provides a theoretical reference for the multi-hazard resilience design and assessment of wind turbine foundations under complex marine environments. Full article

Offshore wind can diversify the Brazilian electricity matrix, but foundation design on the Ceará continental shelf must account for carbonate sands whose stiffness, crushability and stress-dependent response differ from those of quartz sands. This study contribution is the use of carbonate-sand parameters calibrated from consolidated-drained triaxial tests on Ceará-shelf sediments and the direct comparison of two sands with contrasting carbonate contents. The measured responses calibrated the Hardening Soil model in PLAXIS 2D, and the resulting parameters drove PLAXIS 3D simulations of monopiles with different diameters, embedment lengths and tower heights under monotonic lateral loading. The more calcareous sand showed higher frictional strength but lower stiffness—as a result, it mobilised larger mudline displacements, making the Serviceability Limit State more restrictive than the Ultimate Limit State. Pile diameter controlled lateral capacity, whereas reduced L/D lowered system stiffness and serviceability performance. Within the monotonic, homogeneous-profile scope adopted here, M3 (D = 9 m, L = 36 m, L/D = 4) gave the most favourable response for the medium-rated turbine class. The results provide screening-level comparative evidence, not a design-ready proof of feasibility. Full article

Off-grid residential microgrids in tropical regions require storage architectures capable of maintaining renewable electricity supply under variable solar resources, evening demand peaks, and diverse household consumption levels. In PV–battery–hydrogen systems, however, economic indicators can be difficult to interpret when software-reported costs are compared directly with externally calculated LCOE values based on different accounting conventions. This study presents a metric-reconciled techno-economic reconstruction approach for retained PV–battery–hydrogen microgrid configurations serving off-grid residential demand in Chetumal, Mexico. The objective is not to introduce a new global optimization or to claim the universal superiority of a specific architecture, but to separate archived HOMER Pro benchmark outputs from an external techno-economic model (TEM). The TEM reconstructs net present cost, scheduled replacements, salvage treatment, discounted delivered electricity, HOMER-derived LCOE, TEM-derived LCOE, sensitivity indicators, and storage role metrics using declared accounting assumptions. The approach is applied to two representative residential demand scenarios of 16.67 and 53.42 kWh/day. Both retained configurations achieved a 100% renewable fraction with negligible unmet load. Battery discharge increased from 827.12 kWh/year in the low-demand case to 6125.52 kWh/year in the high-demand case, highlighting the increasing role of the battery in short-duration balancing. In contrast, the hydrogen pathway acted as a delayed-backup layer by converting surplus PV electricity into hydrogen and later recovering it through PEM fuel cell generation. The TEM closely matched the HOMER-derived LCOE benchmark, with deviations below 4%, yielding TEM-derived LCOE values of 0.3320 and 0.3571 USD/kWh for the low- and high-demand cases, respectively. Sensitivity analysis showed that delivered electricity, discount rate, PV cost, and battery cost were the main LCOE drivers, while deterministic multi-parameter scenarios confirmed the combined influence of financing, component costs, O&M, PV degradation, and electricity delivered. Overall, the proposed approach provides an auditable basis for metric reconciliation, early-stage technology assessment, and storage role interpretation in tropical off-grid microgrids. Future extensions should include architecture-level re-optimization, flexible loads, degradation-aware modeling, and part-load component behavior. Full article

The factors influencing the cutting efficiency of tunnel boring machine (TBM) cutters in jointed rock masses are very complex. To investigate TBM disc cutter cutting performance under variable cutter spacing and penetration depth, Particle Flow Code (PFC) 2D discrete element numerical simulation is carried out on a granite jointed rock mass. The numerical model adopts a disc cutter tip angle of 20° and tip width of 12 mm, joint spacing of 5 mm, joint inclination angle of 45°, and lateral confining pressure of 2.5 MPa; cutter spacing is set to 60, 80, 100, 120 mm, and penetration depth ranges from 2 mm to 10 mm as research variables. The force chain distribution, jointed rock mass failure modes, penetration load and cutting efficiency of disc cutters under different working conditions are systematically analyzed. An indicator for measuring the cutting efficiency called “crack propagation specific energy” is proposed. Based on the numerical simulation results, a complete quadratic multivariate nonlinear regression model is established to predict cutting efficiency. The results show that the optimal cutting performance occurs at a cutter spacing of 80 mm, where the shear failure proportion of contact bonds and cutting efficiency simultaneously reach the maximum, while incomplete penetration of joint failure surfaces and small cutting areas appear under 60 mm and 120 mm cutter spacing. With the increase in the disc cutter penetration depth, the shear failure proportion of contact bonds rises continuously, and the number of tensile failure microcracks gradually decreases. The research outcomes can provide a theoretical reference for TBM shield tunnel construction parameter optimization. Full article

Rare earth elements (REEs) are predominantly separated by using mixer–settler solvent extraction technology. While this method has been utilized in the industry, it does have a few setbacks, such as requirement of large module footprint to compensate for inefficient separation. Likewise, researchers have turned to membrane separation technology to address these challenges faced by mixer–settler solvent extraction. Supported liquid membranes (SLMs) are a viable alternative in membrane separation technology as they exhibit similar conceptual designs to that of solvent extraction, albeit requiring smaller amounts of organic carrier and lower module footprint compared to mixer settler solvent extraction. In this research, the application of an electrospun membrane was explored using SLMs for the separation between light REEs (LREEs) and heavy REEs (HREEs). To do this, the study initially employs the usage of neodymium (Nd) and dysprosium (Dy) as the baseline for LREEs and HREEs, and later using real REE leachate for the separation between LREEs and HREEs. This study also investigates the effects of different pH of feed solution, organic carrier loading, and stripping concentrations. Overall, to achieve higher selectivity of Nd/Dy, a higher pH of feed solution of 5, a low loading of organic carrier at 10 wt%, and a low stripping concentration of 1 M H₂SO₄ was recommended. For the separation of LREEs and HREEs, a separation factor of 2.38 was achieved with a recovery of 10.43% of LREEs in under 60 min by using a small-scale membrane of 4 cm² effective area. Long term operation indicates a stable LREE/HREE separation performance using the optimized condition. Full article

Nowadays there is still a lack of requirements for the design of non-structural masonry walls. For the case of non-structural autoclaved aerated concrete (AAC) walls with perimeter flexible joints, experimental studies are scarce, and there are no explicit requirements specified in current design codes. In this study, reinforced concrete (RC) frames and RC frame–AAC wall systems were tested under in-plane lateral loads. Systems consisted of an RC frame and a non-structural AAC masonry wall with four perimeter polyurethane joints. The objective of the study was to evaluate the in-plane behavior of non-structural AAC walls. The variables studied were the aspect ratio and the number of intermediate vertical joints of non-structural AAC walls. Lateral load–drift ratio curves of frames and systems were determined. Cracking patterns of frames and systems are presented. Design equations were proposed to determine the lateral load contribution of non-structural AAC walls associated with the first maximum and minimum loads. Design equations were also proposed to determine corresponding drift ratios. It was concluded that experimental lateral load contributions together with corresponding drift ratios were well predicted with the design equations proposed in this study. Full article