Search Results (37,069)

Despite the significant potential of ocean wave energy, the high cost of the generated power remains a major challenge. This highlights the need for innovative conceptual designs that enhance energy conversion while maintaining comparable implementation and installation costs. Recently, the concept of Variable-Shape Buoy Wave Energy Converters (VSB WECs) was introduced that uses flexible buoy material. While many studies have demonstrated the improved performance of VSB WECs compared to Fixed-Shape Buoy Wave Energy Converters (FSB WECs) through numerical simulations, analytical validation is essential to support these findings. This paper presents an analytical derivation of the theoretical limit of power absorption for VSB WECs using the complex-conjugate criteria for the heave motion. In this study, a multi-degree-of-freedom (multi-DoF) VSB WEC model is developed using a thin spherical shell representation, incorporating Rayleigh–Ritz and Love approximations under the assumptions of small deformations and axisymmetric vibration. Hydrodynamic coefficients are computed using a Boundary Element Method (BEM) software. The variation in the theoretical power absorption limit with Young’s modulus is analyzed across a range of elastic materials. As a validation step, the derived theoretical limit criterion is applied to the standard reduced-order single-DoF model of an FSBWEC, successfully yielding the exact theoretical limit reported in the literature. Full article

This study investigates the nonlinear seismic response of elevated rectangular metallic silos subjected to sequential earthquake events, incorporating soil–structure interaction (SSI) and the influence of granular material fullness levels. Using three-dimensional (3D) finite element modeling and real seismic sequences recorded within short time windows, the study evaluates the effects of repeated earthquakes on maximum displacement, residual deformation and base shear. The analysis explicitly incorporates flexible elastic foundation systems to account for SSI effects, which significantly influence dynamic behavior. While considerable research exists on cylindrical silos, the seismic performance of rectangular configurations under multiple consecutive earthquakes remains poorly understood. The research systematically compares structural behavior and deformation patterns under single earthquake events versus multiple consecutive seismic sequences. The results demonstrate that consecutive seismic events produce significantly more severe structural responses than individual earthquake occurrences, with sequential earthquakes leading to amplified residual deformations (30–45% higher), increased stress concentrations in critical regions, and progressive degradation of structural capacity. These findings indicate that conventional single-event seismic design approaches may underestimate the vulnerability of rectangular silos in seismically active areas by approximately 30–40%, highlighting the critical importance of considering multiple-event scenarios in performance-based assessment and design procedures. Full article

This paper addresses the use of discrete-event simulation as a tool for optimizing the production process of an assembly line and identifying the potential for improving production efficiency. A digital model of the manufacturing system was developed in the FlexSim simulation environment based on real production data, technological operation sequences, and statistically defined cycle times. The model was designed to accurately represent real production conditions, including control logic, resource interactions, and material flow. The simulation results were analyzed using graphical and quantitative reports, which enabled the identification of production bottlenecks and inefficient resource utilization. Based on the obtained data, a process optimization strategy was proposed in the form of intelligent operator rotation between workstations to increase operator utilization and improve overall system efficiency. The proposed modifications were subsequently verified through simulation experiments, confirming the preservation of the required production capacity while improving the efficiency of human resource utilization. The findings confirm that simulation modeling represents an effective tool for the analysis, design, and verification of optimization measures, enabling the reduction in operational costs and risks associated with implementing changes in real manufacturing environments. Full article

Background and Objectives: Severe alveolar atrophy may pose significant challenges for dental rehabilitation. Recent advances in digital planning and CAD/CAM technology have renewed the interest in patient-specific subperiosteal implants as a treatment option for anatomically challenging cases. This cohort study evaluated changes in oral health-related quality of life and patient satisfaction following rehabilitation with customized subperiosteal implants in severe alveolar atrophy. Materials and Methods: This cohort study included all consecutive adult patients with severe alveolar atrophy who underwent reconstruction with patient-specific subperiosteal implants at the Department of Oral and Maxillofacial Surgery of “Evangelismos” General Hospital, Athens, Greece, in 2025. Oral health-related quality of life was assessed using the validated OHIP-14 questionnaire preoperatively and 12 months postoperatively. Patient satisfaction was evaluated using a numerical rating scale (NRS). Secondary outcomes included postoperative complications, implant exposure, implant stability, and need for reoperation. Comparisons between baseline and 12-month scores were performed using the Wilcoxon signed-rank test. Results: Nine patients who had completed 12-month follow-up were included. Five were male, and all implants were placed in the maxilla. Significant improvement was observed in oral health-related quality of life, with the median OHIP-14 total score decreasing from 41 preoperatively to 1 at the 12-month follow-up. Patient satisfaction also improved significantly, with the median NRS total score increasing from 17 to 58. Improvements were consistent across all OHIP-14 domains and all NRS items. No major complications were recorded. One patient developed early wound dehiscence, and one patient presented with implant exposure at the anterior palate. At the final follow-up twelve months postoperatively, all implants remained clinically and radiographically stable. Conclusions: These preliminary short-term findings suggest that customized subperiosteal implants may be a promising option for selected patients with severe alveolar atrophy in whom placement of conventional endosseous implants is not feasible; however, the results should be interpreted cautiously given the very small sample size and observational design. Full article

The integration of micro-nano optical structures has become an essential strategy for overcoming the performance bottlenecks of quantum well infrared photodetectors (QWIPs), specifically by addressing the inherent inability of planar devices to couple with normally incident light due to intersubband transition selection rules. A critical factor in this integration is the precise spectral overlap between an optical mode and the material’s excitation mode. Therefore, achieving precise spectral engineering is indispensable. However, conventional electromagnetic simulations act as forward solvers, calculating optical responses based on given geometric parameters. They cannot directly perform inverse design, which involves deriving optimal geometric parameters directly from a desired optical response. Consequently, structural optimization is severely constrained by time-consuming trial-and-error iterations, which often struggle to find the global optimum in a complex design space. To overcome these limitations, this paper presents a comprehensive theoretical and numerical study proposing a deep learning framework for QWIPs coupled with all-dielectric micropillar structures. By establishing a structure-absorption spectrum dataset via finite difference time domain (FDTD) simulations, we developed a dual-network setup. For the forward prediction, a multilayer perceptron (MLP) maps geometric parameters (side length a and period p) to the absorption spectrum, achieving a computational speedup of seven orders of magnitude over traditional numerical simulations. Concurrently, a convolutional neural network (CNN) is employed for the inverse design, realizing on-demand design of geometric parameters based on target spectra with high reconstruction accuracy. Furthermore, the selected all-dielectric micropillar structures are highly compatible with mainstream semiconductor fabrication processes. This research provides an efficient, automated toolkit for the development of high-performance infrared photodetectors. Full article

Traditional pipe roof support design methods generally assume horizontal ground conditions and treat the pipe roof as a monolithic beam, thereby neglecting the differential stress distribution among individual steel pipes under unsymmetrical loading. To address this gap, this paper presents two main contributions: a low-carbon cement-based grouting material suitable for pipe roof reinforcement, and a new mechanical model that simultaneously accounts for biased pressure conditions and the inter-pipe micro-arch effect. First, the working performance of limestone calcined clay cement (LC³) grout was systematically tested at a water–cement ratio of 1:1, and the optimal mix ratio was determined. Grout–soil reinforcement tests on weathered granite show that, for grout-to-soil volume ratios between 0.2 and 0.8, the compressive strength of the reinforced material exceeds 10 MPa and the elastic modulus exceeds 600 MPa. Second, a mechanical model for the pipe roof was established based on the Pasternak two-parameter foundation theory, incorporating both biased pressure conditions and the inter-pipe micro-arch effect. The model predictions were compared with existing field monitoring data in the literature, showing consistent trends and good agreement in peak deflection values. Parametric analysis reveals that under horizontal ground conditions, the pipe roof response is symmetric, with the vault as the most critical area. As the bias angle increases, the maximum response shifts toward the higher side of the terrain, and the stress difference between pipes on both sides increases significantly. Theoretical analysis of the low-carbon grouting material shows that pipe roof deflection is moderately reduced compared to traditional grouting materials, but at the cost of increasing bending moment and shear force within the steel pipes. The proposed low-carbon grouting material and the validated mechanical model provide theoretical support for the design optimization of pipe roof support in shallow unsymmetrical loading tunnels. Full article

Metal mesh reflective surfaces are widely used in deployable antennas mounted on satellites where lightweight and stowability are required; however, quantitative characterization of reflective performance is difficult due to complex woven/knitted structures. This paper presents a modeling method that characterizes the reflection coefficient of complex mesh fabrics by combining a per-band effective wire radius r_eff estimation procedure with the Casey surface impedance model. The lattice spacing is fixed from the specimen geometry, the electrical conductivity is set to the material property of gold ($\sigma$ = 45.2 MS/m), and r_eff is determined as a single parameter that minimizes the error against the measured reflection coefficient in each frequency band. For validation, waveguide-contact measurements were performed on three Atlas-series mesh specimens fabricated with gold-coated molybdenum wire (diameter: 30 μm), measuring each specimen across all three waveguide standards (WR-340, WR-90, WR-28) with nine repeated trials per configuration, totaling 162 measurement runs. The estimated r_eff ranged from 10.1 to 44.5 μm depending on band and polarization, with RMSE below 0.021 dB in all native-band fits. Even for the same specimen, directional r_eff values differed by up to 1.78× due to the anisotropy of the weave structure, confirming that polarization dependence must be considered in mesh reflector antenna design. Full article

Background and Objectives: Enhanced Recovery After Surgery (ERAS) pathways are increasingly used in spine surgery, but uptake in adolescent idiopathic scoliosis (AIS) remains heterogeneous across institutions. Evidence in pediatric deformity surgery supports shorter recovery with protocolized care, yet real-world comparative data combining ERAS and the erector spinae plane block (ESPB) remain limited. This study aimed to compare early postoperative outcomes between a historical standard-care pathway and a structured ERAS+ESPB pathway in adolescents undergoing posterior spinal fusion for AIS. Materials and Methods: A single-center retrospective time-based comparative cohort study design included consecutive AIS patients (<18 years) treated between 1 January 2024 and 31 December 2025. The standard-care pathway was applied to patients operated on before 1 June 2025 (n = 34), whereas the ERAS+ESPB pathway was applied to those operated on from 1 June 2025 onward (n = 35), following formal institutional implementation. Outcomes included postoperative pain assessed using the visual analog scale under two functional conditions—at rest in the supine position and during standing/mobilization—at POD0, POD1, POD2, POD3, discharge, and 2-week follow-up; postoperative nausea at POD0–POD3; and length of stay (LOS). Between-group pain comparisons used Welch’s t-test; nausea used Fisher’s exact test; LOS used the Wilcoxon rank-sum test. Results: At POD0, supine pain was lower in ERAS+ESPB (1.50 ± 0.55) than in standard care (3.20 ± 1.50; p < 0.001). From POD1 onward, supine pain did not differ significantly between groups. Among assessable patients, standing pain was lower in ERAS+ESPB at POD2 (3.05 ± 1.53 vs. 4.50 ± 1.05; p = 0.020), POD3 (2.82 ± 1.62 vs. 4.17 ± 1.03; p = 0.006), and 2-week follow-up (1.45 ± 0.80 vs. 2.26 ± 0.93; p = 0.006). Nausea was lower in ERAS+ESPB at POD0 (11.4% vs. 35.3%; p = 0.024) and POD2 (8.6% vs. 32.4%; p = 0.018), with no significant differences at POD1 or POD3. LOS was shorter in ERAS+ESPB (5.41 ± 1.10 vs. 8.32 ± 2.06 nights; p < 0.001). Conclusions: In adolescents undergoing posterior spinal fusion for AIS, an ERAS-based perioperative pathway incorporating ESPB was associated with improved early postoperative recovery, particularly in terms of immediate postoperative pain, pain during mobilization, early postoperative nausea at selected time points, and length of hospital stay. Prospective multicenter studies are needed to confirm these findings and clarify the independent contribution of individual pathway components. Full article

The performance, safety, and long-term durability of electric vehicle (EV) battery systems are strongly governed by the chemical stability and thermophysical properties of their constituent materials. In response to the limitations of conventional lithium-based batteries—particularly with respect to thermal stability, material sustainability, and degradation under high operational loads—this study presents a thermodynamic and electrochemical modeling framework for evaluating alternative battery materials relevant to electric vehicle energy storage systems. Xenon difluoride (XeF₂) and zirconium carbide (ZrC) are proposed as functional battery components and comparatively analyzed based on chemical stability, bond enthalpy, mass–capacity relationships, and energy density characteristics. Analytical modeling is employed to investigate voltage–capacity–mass interactions over a wide operating range (3–48 V and 100–1000 mAh), representing diverse EV operating scenarios, including high-load and elevated-temperature conditions. In addition, temperature-dependent degradation behavior and cycle life performance are assessed using logarithmic degradation models and Arrhenius-based life cycle formulations. The results indicate that ZrC, with a high total bond enthalpy of 561 kJ mol⁻¹, demonstrates superior energy density, reduced material mass requirements, and enhanced resistance to thermal degradation, making it particularly suitable for high-temperature and long-life EV battery applications. In contrast, XeF₂ exhibits stable electrochemical performance under moderate temperature and capacity conditions but shows increased sensitivity to thermal effects at higher operating ranges, suggesting potential applicability in balanced-performance EV battery configurations. Overall, the proposed modeling framework provides a systematic approach for assessing alternative battery materials under electric vehicle-relevant operating conditions and offers guidance for future experimental validation, material selection, and battery design aimed at improving safety, durability, and sustainability in next-generation electric vehicle energy storage systems. Full article

In 2026, sustainable construction materials research is focused on optimization of the resources’ circularity, carbon reduction, and performance improvements through advanced materials. Biochar, nanomaterials, and recycled aggregates (RA) are enhancing concrete by improving strength, durability, and carbon capture, while supporting low-carbon, circular practices. When used in low-carbon alkali-activated materials (AAMs), these materials reduce greenhouse gas emissions by approximately 30–60% compared to Portland cement (PC). Despite challenges in cost, standardization, and large-scale production, these innovations are advancing the construction industry towards sustainable, carbon-neutral solutions. RA helps reduce landfill waste and converse resources, though issues like quality variability and potential contaminants must be addressed. Biochar’s (0.5–2 wt.% of binder) adoption is limited by inconsistent properties, while nanomaterials (0.01 to 3 wt.% of binder) offer improved mechanical properties (5–20%) but face high production costs and limited long-term data. In the coming years, efforts will focus on standardizing production, improving nanoparticle dispersion, and refining RA processing. The integration of AI and machine learning may further optimize material design, leading to greener, low-carbon materials for large-scale, sustainable infrastructure by 2036. Full article

As a composite structure with both support and load-bearing functions, the composite underground structure wall has been widely applied in engineering. However, in terms of scientific research, a simplified calculation method that can reflect the internal force distribution law and the interaction mechanism between the two walls has not been found. In terms of design applications, the internal force calculated by the traditional total method has a relatively large deviation from the actual situation. This study proposes an internal force calculation method for composite underground structure walls based on the incremental method. The difference between the at-rest earth–water pressure and the active earth–water pressure is taken as the load increment, which is applied step-by-step according to the construction conditions. Based on the Wangsheren Subway Station in Jinan, China, the actual bending moments of the diaphragm wall and inner lining wall are back-analysis using Plaxis 2D V20 with measured horizontal deformation as input. Models of the incremental method and total method are built in Midas GEN 2022. Bending moment distributions under various conditions are compared. The results show the following: (1) The absolute values of the bending moments of the two walls calculated by the incremental method are inversely proportional along the depth direction, which is consistent with the trend of back-analysis, while the absolute values of the bending moments of the two walls calculated by the total method are directly proportional. (2) The incremental method has a higher calculation accuracy for the characteristic points of the bending moment. In terms of calculated values, the bending moment of the diaphragm wall is 0.87–1.90 times that of the back-analysis, and that of the inner lining wall is 1.06–4.93 times, while the deviation of the total method is significantly larger (0.47–3.34 times for the diaphragm wall and 1.49–16.64 times for the inner lining wall). (3) Under complex working conditions, the calculation results of the incremental method are still better than those of the total method. This incremental method can better simulate the interaction mechanism and the internal force redistribution characteristics of the composite underground structure wall. The calculation results are more in line with the engineering reality, which can save materials while ensuring the structural safety and provides a more scientific theoretical method for relevant designs. Full article

Nowadays, organic, inorganic, and microbial pollutants are listed as a substantial threat to the environment as well as public health, leading to water contamination. Green technologies such as photocatalytic and photoelectrocatalytic processes have appeared as favorable tools for water remediation, leading to effective degradation of pollutants under environmentally relevant operating conditions. With the rapid development of photocatalysis in the 21st century, heterogeneous catalysts have been extensively engineered to improve light utilization and promote surface redox reactions. This review presents an overview of recent advances in the synthesis, design, and application of heterogeneous catalysts for water purification. Key reaction mechanisms, material modifications, and hybrid processes are discussed. Also, the growing need for environmentally friendly, sustainable, and cost-effective catalytic materials is underlined. Attention was given to the role of molecular modeling in understanding catalytic mechanisms and guiding the design of efficient and sustainable catalytic materials. By critically analyzing contemporary progress, limitations, and emerging trends, this review directs future research activities towards increasingly efficient and scalable water purification methods. Full article

Cranial cruciate ligament rupture is a common orthopedic condition in dogs, and tibial tuberosity advancement is a well-established surgical treatment. The aim of this retrospective study was to evaluate the short-term clinical and radiographic outcomes of a cageless tibial tuberosity advancement technique in small-breed dogs. Medical records of 63 dogs (77 stifles) treated using this technique were reviewed. Fixation was achieved using three construct types: a screw–pin construct (the majority of cases), a screw-only construct, or a screw combined with two pins. Due to small subgroup sizes, fixation-type outcomes were primarily analyzed descriptively. Clinical and radiographic evaluations were performed immediately after surgery and at eight weeks postoperatively. Clinical outcomes were graded based on limb function, and radiographic bone healing was scored using a standardized scale. Postoperative complications were recorded and analyzed in relation to patient and procedural variables. No intraoperative complications were observed, while postoperative complications occurred in 27% of dogs and were predominantly minor and implant-related. Lameness scores improved significantly over the follow-up period. All treated stifles demonstrated stable implants, maintained advancement, and satisfactory bone healing. The use of bone graft material appeared to be associated with fewer complications and more favorable clinical outcomes; however, this observation should be interpreted with caution given the retrospective and non-randomized design of the study. In this retrospective case series, cageless tibial tuberosity advancement using screw-based fixation (predominantly screw–pin constructs) was associated with favorable short-term clinical and radiographic outcomes. These findings should be considered preliminary and limited to short-term evaluation, given the retrospective design, absence of a control group, and relatively short follow-up period. Further prospective studies with larger populations, standardized outcome measures, and longer follow-up are warranted to confirm these findings. Full article

Ga-based liquid metals (GLMs) have been considered as promising thermal and electrical interface materials for advanced power electronics, combining high thermal conductivity (some types even >30 W/m·K) with fluidity at room temperature. This review systematically evaluates the dual roles of GLMs in power electronics packaging. Their function in thermal management as both thermal interface materials and active cooling media is first examined, followed by an analysis of their capabilities in forming electrical interconnections via low-temperature bonding in fluidic and solid states. However, reliable integration remains challenging due to interfacial reactions and instability with metal substrates. We discuss interfacial mechanisms with Cu and common metallizations, along with emerging regulation strategies such as surface coatings and process acceleration techniques. By examining these interfacial interactions, this work aims to guide the selection and design of surface modification strategies to either promote or inhibit reactions as needed, supporting the development of robust power electronic packaging. Full article

This study presents a comparative investigation of MgCu intermetallic compounds, CuCoMnSn Heusler alloys, and carbon steel for spur gear applications using a novel tooth contact analysis (TCA) method. The TCA employs a nonlinear two-variable equation, providing a fast and accurate computational tool for evaluating gear contact behavior. By integrating material-specific elastic properties from density functional theory (DFT) studies, the analysis predicts contact paths, stress distributions, and responses to angular misalignments. Material selection strongly influences gear performance: MgCu is promising for lightweight applications, while CuCoMnSn is better suited where mechanical performance is prioritized. The CuCoMnSn alloy also exhibits half-metallic ferromagnetic behavior, offering potential functional advantages beyond mechanical performance. These results highlight the promise of intermetallics and Heusler alloys for high-performance, misalignment-tolerant gears and demonstrate the effectiveness of combining DFT-informed material modeling with the novel TCA method for optimized spur gear design. Full article