Search Results (885)

To explore the application of precast concrete construction methods in underground stations, a combined precast and cast in situ construction method was adopted for a long-span column-free underground subway station. To study the stability of large-span underground arch structures under asymmetric loading, a full-scale test was conducted using the displacement-force control method. Steel blocks were used to simulate the overlying soil and additional loads on the upper surface of the arch, while the displacement of the arch foot was applied by adjusting the tension of the cables. The maximum tensile stress and maximum compressive stress of the steel bars appeared at the midpoints of the left and right arches, which were less than the yield stress of the steel bars. The results show that the structural stability meets the design requirements and provides a considerable safety margin. A comprehensive analysis of the arch structure under asymmetric loading was carried out through on-site monitoring, numerical simulation, and analytical solutions. The results are in good agreement: compared with the experimental results, the calculated values increase the maximum deflection of the arch by 13.67%, which verifies the reliability of the numerical simulation and analytical solution methods under the same boundary conditions. However, restricted by test conditions, the loading in this study was only applied on one side of the arch crown, which differs from the actual working condition involving full loading first followed by unloading on one side. Full article

Background and Objectives: Adequate buccal bone thickness is critical for long-term peri-implant health and stability. When residual alveolar bone volume is insufficient, guided bone regeneration (GBR) is a widely adopted technique. While non-resorbable membranes provide structural support, they carry a higher risk of complications and require secondary surgery. Resorbable collagen membranes, offer promising biological properties and easier clinical handling, yet clinical data remain limited. This prospective cohort study aimed to evaluate the clinical and radiographic outcomes of horizontal GBR using a native, non–cross-linked resorbable porcine pericardium membrane fixed with titanium pins, in conjunction with simultaneous implant placement. Materials and Methods: Eighteen patients (26 implants) with horizontal alveolar defects (<6 mm) underwent implant placement and GBR with deproteinized bovine bone mineral and a porcine pericardium collagen membrane. Horizontal bone gain and buccal bone thickness were measured at baseline and 6 months post-operatively. Post-operative complications, patient-reported outcomes (PROMs), and peri-implant tissue health were assessed up to 1 year post-loading. Results: Mean bone gain was 2.95 ± 0.95 mm, and all sites achieved a buccal bone thickness ≥ 1.5 mm. No membrane-related complications occurred. PROMs revealed low morbidity. At 1-year follow-up, marginal bone loss averaged 0.54 ± 0.7 mm, mean probing depth was 2.79 ± 0.78 mm, 92% of sites exhibited keratinized mucosa ≥ 2 mm. Conclusions: Native resorbable porcine pericardium membranes, when combined with DBBM and mechanical stabilization, seem to be effective for horizontal bone regeneration. Full article

The objective of this study was to propose a correlation model of the damage class and deformation of reinforced concrete (RC) beams damaged by earthquakes with a focus on columns and walls. For this purpose, a series of full-scale RC beam specimens with different shear strength margins were tested under cyclic lateral loading to examine their deformation performance and damage states. Then, the damage class and seismic capacity reduction factor of RC beams were evaluated based on the test results. The results showed that the tendency of shear failure, such as shear crack pattern and shear deformation component, of specimens with small shear strength margins was more remarkable, and its maximum residual crack widths tended to be slightly larger and dominated by shear cracks. The results also indicated that the effect of the shear strength margin on the seismic capacity reduction factor which represents the residual seismic performance of RC beams was limited, whereas the specimen with a smaller shear strength margin exhibited lower ultimate deformation capacity. In addition, there was a difference in the boundary value of the lateral drift angle which classifies the damage class of specimens with different shear strength margins. Finally, correlation models between the damage class and deformation of RC beams with different deformation capacities were proposed. Full article

This study investigates the axial performance of continuous helix screw piles compared to helical piles through full-scale compression and tension load testing in layered soils. Twenty-three piles were installed and tested. The results demonstrate that screw piles can achieve considerable axial capacity with lower installation torque than helical piles, particularly under tensile loading. The capacity-torque relationship for screw piles was more consistent across both compression and tension, likely due to reduced soil disturbance from the smaller helix projection. Strain gauge measurements indicated that screw piles act primarily as friction piles with the threaded shaft carrying most of the load, especially in stiff clay. On the other hand, the smooth portion of the pile shaft contributed only marginally to resistance in compression and none in tension. The calculated capacity based on theoretical equations aligned well with field results in compression, with screw piles best represented by cylindrical shear failure in sand and a combination of cylindrical shear and individual bearing failure in clay. However, there is greater variability between calculated and measured uplift capacity, possibly due to soil disturbance effects. Additionally, the commonly used helix spacing ratio (S/D) was found to be less applicable to screw piles in predicting failure mode due to their smaller shaft-to-helix diameter difference. Full article

In winter, stay cable sheaths are prone to icing, which increases cable loads and poses a falling-ice hazard upon thawing. While manual and chemical de-icing are common methods, their safety and cost drawbacks make robotic de-icing a promising alternative. Robotic de-icing offers a promising alternative. However, to protect the sheath from damage, the de-icing blade is designed to minimize contact with its surface. Consequently, a thin layer of residual ice is often left behind, which reduces the surface friction coefficient and complicates the climbing process. This study evaluates the climbing performance of a self-manufactured cable-climbing mechanism through laboratory tests and dynamic simulations (ADAMS). A physical prototype was built, and dynamic simulations of the cable-climbing mechanism were conducted using Automated Dynamic Analysis of Mechanical Systems (ADAMS) software. The preliminary validation results demonstrate that the mechanism is capable of maintaining stable climbing under extreme conditions, including a friction coefficient of 0.12 to reflect thin-ice variability and indicated stable climbing even at μ = 0.12), a vertical inclination of 90°, and a load of 12 kg, confirming the design’s validity. Furthermore, we analyzed key parameters. A lower friction coefficient requires a higher clamping force and adversely affects the climbing speed due to increased slip. Similarly, an increased payload elevates the mechanism’s deflection angle, spring force, and wheel torque, which in turn reduces the climbing speed. Cable inclination has a complex effect: deflection decreases with slope, yet clamping force peaks near 70°, showing a bell-shaped trend. This peak requirement dictated the damping spring selection, which was given a safety margin. This ensures safe operation and acceleration at all other angles. Limitations: The present results constitute a feasibility validation under controlled laboratory conditions and rigid-support simulations. The long-term effects of residual ice and field performance remain to be confirmed in planned field trials. Full article

Cell towers play a key role in providing telecommunications infrastructure, especially in remote mountainous regions. This paper presents an approach to the efficient design of 42-metre-high cell towers intended to install high-power equipment in remote mountainous regions of the Carpathians (750 m above sea level). The region requires rapid deployment of many standardized towers adapted to geographical features. The main design challenges were the limited space available for the base, the impact of extreme weather conditions, and the need for a fast project implementation due to the critical importance of ensuring stable communication. Special methodological attention is given to how the transition between pyramidal and prismatic segments in cell tower shafts influences overall structural performance. The effect of this geometric boundary on structural efficiency and material usage has not been addressed in previous studies. A dedicated investigation shows that positioning the transition at a height of 33 m yields the best compromise between stiffness and weight, minimizing a generalized penalty function that accounts for both the horizontal displacement of the tower top and its total mass. Modal analysis confirms that the chosen configuration maintains a natural frequency of 1.68 Hz, ensuring a safe margin from resonance. For the final analysis of the behavior of towers with elements of different cross-sectional shapes, finite element modeling was used for a detailed numerical study of their structural and performance characteristics. This allowed us to assess the impact of geometric constraints of structures and take into account the most unfavorable combinations of static and dynamic loads. The study yields a concise rule of thumb for towers with compact foundations, namely that the pyramidal-to-prismatic transition should be placed at roughly 78–80% of the total tower height. Full article

The autonomous navigation of inspection robots in complex forest environments heavily relies on accurate trunk detection. However, existing detection models struggle to achieve both high accuracy and real-time performance on resource-constrained edge devices. To address this challenge, this study proposes a lightweight algorithm named YOLOv11-TrunkLight. The core innovations of the algorithm include (1) a novel StarNet_Trunk backbone network, which replaces traditional residual connections with element-wise multiplication and incorporates depthwise separable convolutions, significantly reducing computational complexity while maintaining a large receptive field; (2) the C2DA deformable attention module, which effectively handles the geometric deformation of tree trunks through dynamic relative position bias encoding; and (3) the EffiDet detection head, which improves detection speed and reduces the number of parameters through dual-path feature decoupling and a dynamic anchor mechanism. Experimental results demonstrate that compared to the baseline YOLOv11 model, our method improves detection speed by 13.5%, reduces the number of parameters by 34.6%, and decreases computational load (FLOPs) by 39.7%, while the average precision (mAP) is only marginally reduced by 0.1%. These advancements make the algorithm particularly suitable for deployment on resource-constrained edge devices of inspection robots, providing reliable technical support for intelligent forestry management. Full article

In offshore drilling and geological exploration, the stability of jack-up rigs is predominantly determined by the bearing capacities of spudcan foundations during seabed penetration. The penetration depth of spudcans is relatively shallow in hard clay. The formation of a cavity on the top surface of a spudcan often complicates accurate estimation of its capacity. This study employs the finite element method, in conjunction with the Swipe and Probe loading techniques, to examine the failure surfaces of soils of varying strengths. Numerical simulations that consider different gradients of undrained shear strength and cavity depths demonstrate that cavity depth significantly influences the failure envelope. The findings indicate that higher soil strength increases the bearing capacity and reduces the area of soil displacement at failure. Moreover, an enhanced theoretical equation for predicting the vertical-horizontal-moment (V-H-M) failure envelope in hard clay strata is proposed. The equation’s accuracy has been verified against numerical simulation results, revealing an error margin of 3–10% under high vertical loads. This model serves as a practical and valuable tool for assessing the stability of jack-up rigs in hard clay, providing critical insights for engineering design safety and risk assessment. Full article

Background: Chronic pain significantly impacts quality of life and may lead to physical and psychological dysfunction. Although various tools have been developed to assess pain-related conditions, many are composed of time-consuming multi-item questionnaires, limiting practicality in clinical settings. The Multidimensional Evaluation Scale for Patient Impression of Change (MPIC) was developed as a simple, retrospective tool to assess multiple domains targeted in interdisciplinary pain management. This study evaluated the reliability and validity of the Japanese MPIC in patients with chronic non-cancer pain. Methods: We recruited 101 participants from the Interdisciplinary Pain Center at Keio University Hospital between August 2022 and September 2024. Pretreatment measures included pain intensity, disability, catastrophizing, self-efficacy, psychological distress, and sleep quality. Baseline assessments encompassed pain intensity, disability, catastrophizing, self-efficacy, psychological distress, and sleep quality. Psychological distress was evaluated using the Hospital Anxiety and Depression Scale (HADS) for the initial cohort of 35 participants and the Kessler Psychological Distress Scale (K6) for the subsequent 66 participants. Following the intervention, participants completed the MPIC, in addition to reassessments of pain intensity, disability, catastrophizing, self-efficacy, psychological distress (HADS or K6), and sleep quality. Retesting the MPIC was performed in a small subgroup of 20 participants for test–retest reliability analysis. Confirmatory factor analysis (CFA), average variance extracted (AVE), Pearson’s correlations with pain-related measures, Cronbach’s alpha, and intraclass correlation coefficients (ICC) were used to assess construct validity, convergent validity, criterion validity, internal consistency, and reliability. Results: CFA indicated marginal fit (CFI = 0.86, RMSEA = 0.23, SRMR = 0.06), with factor loadings from 0.49 to 0.91. AVE supported convergent validity (0.58). Internal consistency was excellent (Cronbach’s alpha = 0.93), and ICC was moderate (0.52). MPIC domains correlated significantly with changes in pain intensity, disability, catastrophizing, self-efficacy, sleep, and psychological distress (p < 0.05), supporting criterion validity. Conclusions: The Japanese MPIC provides preliminary evidence of validity and reliability, with acceptable internal consistency, marginal structural fit, and moderate test–retest reliability. These findings suggest that the MPIC may serve as a concise retrospective instrument for assessing multidimensional treatment outcomes within interdisciplinary pain management programs for chronic non-cancer pain. Full article

The growing dependence on fossil fuels has raised concerns over energy security, resource depletion, and environmental impacts, driving the need for renewable alternatives. Coffee husk, a widely available agro-industrial residue, represents an underutilized feedstock for biodiesel production. In this study, biodiesel was synthesized from coffee husk oil using a two-step transesterification process to address its high free fatty acid content (21%). Physicochemical analysis showed that Coffee Husk Oil Methyl Ester (CHOME) possessed a density of 863 kg m⁻³, viscosity of 4.85 cSt, and calorific value of 33.51 MJ kg⁻¹, compared to diesel with 812 kg m⁻³, 2.3 cSt, and 42.4 MJ kg⁻¹. FTIR analysis confirmed the presence of ester carbonyl and C–O functional groups characteristic of CHOME, influencing its combustion behavior. Engine tests were then conducted using B0, B10, B30, B50, and B100 blends under different loads, both with and without fuel preheating. Results showed that neat CHOME (B100) exhibited 11.8% lower brake thermal efficiency (BTE) than diesel, but preheating at 95 °C improved BTE by 5%, with preheated B10 slightly surpassing diesel by 0.5%. Preheating also reduced brake-specific fuel consumption by up to 7.75%. Emission analysis revealed that B100 achieved reductions of 6.4% CO, 8.3% HC, and 7.0% smoke opacity, while NOx increased only marginally (2.86%). Overall, fuel preheating effectively mitigated viscosity-related drawbacks, enabling coffee husk biodiesel to deliver competitive performance with lower emissions, highlighting its potential as a sustainable waste-to-energy fuel. Full article

Steel-reinforced concrete (SRC) structures combine steel skeletons with concrete components, improving load-bearing capacity and streamlining construction. In this study, four full-size lattice SRC members were tested under pure bending to validate fundamental assumptions and were further analyzed numerically. The experimental specimens demonstrated a 15.3% increase in ultimate load-carrying capacity and an average 58.7% increase in the ductility index compared with conventional members. Notably, the improvement in ductility was substantially greater than the enhancement in load-bearing capacity. In parallel, a load-bearing capacity formula for lattice SRC members was proposed, yielding an error margin of 0.136 when compared with existing formulae for section steel members. The flexural strength predictions of formulae derived from simplified elastic–plastic theory and numerical analysis agreed with the test results. Full article

This work suggests a new use for the Non-Monopolize Optimization (NO) method to improve the dynamic stability and robustness of PID and PIDA controllers in Automatic Voltage Regulator (AVR) systems when there are load disruptions. The NO algorithm is a new search method that does not use metaphors and only looks for one answer. It utilizes adaptive dimension modifications to strike a balance between exploration and exploitation. Its addition to AVR control makes parameter tweaking more efficient, without relying on random metaphors or population-based heuristics. MATLAB/Simulink R2025a runs full simulations to check how well the system works in both the time domain (step response, root locus) and the frequency domain (Bode plot). We compare the results to those of well-known optimizers like WOA, TLBO, ARO, GOA, and GA. The suggested NO-based PID and PIDA controllers always show less overshoot, faster rise and settling periods, and higher phase and gain margins, which proves that they are more stable and responsive. A robustness test with a load change of ±50% shows that NO-tuned controllers are even more reliable. The results show that using NO to tune different controllers could be a good choice for real-time AVR controller tuning in modern power systems because it is lightweight and works well. Full article

BioFlx crowns represent an innovative hybrid resin polymer-based alternative for pediatric full-coverage restorations, addressing the clinical dilemma between durable-but-unaesthetic stainless steel crowns (SSCs) and technique-sensitive zirconia crowns. This narrative review synthesizes current evidence of BioFlx crowns’ mechanical properties, clinical performance, and material characteristics through a comprehensive literature search across PubMed, Scopus, and Web of Science from August through September 2025. The search identified 18 studies comprising four randomized controlled trials, two case reports/series, and twelve in vitro studies. In vitro analyses demonstrated favorable stress distribution under physiological loads (≤311 N) with notable brand-dependent performance variations. NuSmile BioFlx exhibited greater wear than zirconia, but superior wear resistance compared to SSCs, while Kids-e-Dental BioFlx crowns demonstrated less crown wear relative to zirconia, with both brands causing less antagonist wear than zirconia. BioFlx showed intermediate fracture resistance, comparable surface roughness to SSCs but higher than zirconia, and intermediate marginal gaps. Resin cements demonstrated superior retention compared to manufacturer-recommended glass ionomer and resin-modified glass ionomer cements. Clinical studies with a 12 month follow-up demonstrated 92–98% retention rates compared to 100% for SSCs, with significantly higher patient satisfaction and reduced plaque accumulation versus SSCs. However, a failure rate of 6.7% was observed. Color change values were lower than those of zirconia crowns; however, they remained clinically unacceptable (ΔE > 3.3), and stain resistance was lower than that of SSCs. Marginal integrity remained clinically acceptable, though some anatomic form deterioration occurred over time. Case reports highlighted clinical utility in nickel-allergic patients and for masking silver diamine fluoride discoloration. BioFlx crowns represent a clinically valuable esthetic alternative in pediatric dentistry, though evidence remains limited by recent market introduction, brand-specific performance variations (NuSmile vs. Kids-e-Dental), anterior tooth applicability constraints, and contraindications in bruxism and for the Hall technique. Future randomized controlled trials with ≥2 year follow-up periods are imperative to establish long-term performance. Until such evidence emerges, BioFlx crowns represent a viable clinical option for esthetically sensitive cases and nickel-allergic patients when applied with rigorous case selection. Full article

In many countries, most one-phase residential electricity consumers are supplied from three-phase, four-wire local networks operated in radial tree-like configurations. Uneven consumer placement on the wires of the three-phase circuit leads to unbalanced phase loads that break the voltage symmetry and increase the energy losses. One way to mitigate these problems is to balance the phase loads on the feeders by choosing the optimal phase of connection of the consumers. The authors proposed earlier a phase balancing algorithm based on metaheuristic optimization. For networks with a high number of supply nodes, this algorithm requires finding a solution for all the consumers simultaneously. Two alternative approaches are proposed in this paper that use the tree-like structure of the network to divide the optimization between a main distribution feeder and several branches, creating a multistage process, with the aim of minimizing energy losses. A case study is performed using a real low-voltage distribution network and a comparison is made between the three algorithms. The resulting losses have marginal variations between the proposed approaches, with a maximum of 1.3% difference. Full article

This study presents a numerical analysis of a road embankment constructed over soft subsoil and reinforced with geogrids and jet grout columns to enhance stability and reduce deformation. The two-dimensional finite element software PLAXIS (PLAXIS 2D Version 2023.2) was employed to simulate both the static and dynamic behavior of the system under real field conditions, utilizing geotechnical parameters obtained from in situ and laboratory tests. The unreinforced embankment exhibited significant vertical and lateral displacements, attributed to inadequate compaction and insufficient bearing capacity of the foundation soil. Finite element simulations were first used to replicate the observed field performance, confirming the accuracy of the modeling approach. Subsequently, reinforcement strategies involving the integration of jet grout columns and geogrid layers were analyzed to assess their effectiveness. The jet grout columns significantly improved subsoil stiffness, while the geogrid reinforcement contributed to the stabilization of embankment slopes. The results demonstrated a 220% increase in the safety factor and a 65% reduction in total settlement compared to the unreinforced case. Additionally, dynamic analysis revealed that while the embankment maintained marginal stability at a horizontal acceleration of 0.30 g, it failed under a 0.40 g seismic load. These findings highlight the critical role of combined reinforcement techniques and process-based modeling in ensuring not only the stability of road embankments on weak soils but also their contribution to sustainable infrastructure development through improved durability, resource efficiency, and extended service life. Full article