Search Results (2,099)

In this study, an effective strengthening method was investigated to improve the seismic performance of masonry brick walls. The strengthening method comprised the use of shotcrete, which was applied in both glass fiber-reinforced and unreinforced forms for steel plates and tie rods. Thirteen wall specimens constructed with vertical perforated masonry block bricks were tested under diagonal compression in accordance with ASTM E519 (2010). Reinforcement plates with different thicknesses (1.5 mm, 2 mm, and 3 mm) were anchored using 6 mm diameter tie rods. A specially designed steel frame and an experimental loading program with controlled deformation increments were employed to simulate the effects of reinforced concrete beam frame system on walls under the effect of diagonal loads caused by seismic loads. In addition, numerical simulations were conducted using three-dimensional finite element models in Abaqus Explicit software to validate the experimental results. The findings demonstrated that increasing the number of tie rods enhanced the shear strength and overall behavior of the walls. Steel plates effectively absorbed tensile stresses and limited crack propagation, while the fiber reinforcement in the shotcrete further improved wall strength and ductility. Overall, the proposed strengthening techniques provided significant improvements in the seismic resistance and energy absorption capacity of masonry walls, offering practical and reliable solutions to enhance the safety and durability of existing masonry structures. Full article

To solve the limitations of these models for submicron materials like electrospun nanofiber membranes, a numerical simulation was used to construct a three-dimensional model closer to the actual structure to explore the filtration resistance and efficiency of these membranes. Based on the actual polydisperse electrospun nanofiber filter, the three-dimensional structure (fiber diameter 280 nm–1300 nm, thickness 0.0150 mm–0.0240 mm, and solid volume fraction 11.3–17.7%) was reconstructed by GeoDict software. The filtration resistance was simulated with the FlowDict module (surface velocity 6.89 cm/s, 20 °C), and the filtration efficiency was calculated with the FilterDict module (2.5 μm particles, tracking 20,000). The results are compared with the experimental values, Davids empirical formula, Happel model, and Kuwabara model. The results show that the simulated values of filtration resistance are generally higher than the experimental values (deviation ≤ 20%), among which the simulation and experiment have the highest consistency, followed by the Davids formula (such as the relative error of 41.62% at 9% spinning solution concentration), and the Kuwabara model has the largest error (59.86%). The simulated value of filtration efficiency is higher than the experimental value (deviation ≤ 7%), because the model assumes that the particles adhere directly after contacting the fiber, and the actual sliding off is not considered. This study confirms that numerical simulation can efficiently predict the filtration performance of electrospun nanofiber membranes. Therefore, it provides a basis for optimizing material structure by adjusting spinning parameters and promoting the engineering application of submicron filter materials. Full article

With rising global temperatures and increasing sustainability demands, the need for advanced pavement solutions has never been greater. This study breaks new ground by integrating phase change materials (PCMs), including paraffin-based wax (Rubitherm RT55), hydrated salt (Climator Salt S10), and fatty acid (lauric acid), as binder modifiers within warm mix asphalt (WMA) mixtures. Moving beyond the traditional focus on binder-only modifications, this research utilizes recycled cigarette filters (CFs) as a dual-purpose fiber additive, directly reinforcing the asphalt mixture while simultaneously transforming a major urban waste stream into valuable infrastructure. The performance of the developed WMA mixture has been evaluated in terms of stiffness behavior using an Indirect Tensile Strength Modulus (ITSM) test, permanent deformation using a static creep strain test, and rutting resistance using the Hamburg wheel-track test. Laboratory tests demonstrated that the incorporation of PCMs and recycled CFs into WMA mixtures led to remarkable improvements in stiffness, deformation resistance, and rutting performance. Modified mixes consistently outperformed the control, achieving up to 15% higher stiffness after 7 days of curing, 36% lower creep strain after 4000 s, and 64% reduction in rut depth at 20,000 passes. Cost–benefit analysis and service life prediction show that, despite costing USD 0.71 more per square meter with 5 cm thickness, the modified WMA mixture delivers much greater durability and rutting resistance, extending service life to 19–29 years compared to 10–15 years for the control. This highlights the value of these modifications for durable, sustainable pavements. Full article

Purpose: The present study aims to evaluate alterations in the peripapillary retinal nerve fiber layer (RNFL) thickness in pediatric patients following surgical resection of childhood-onset craniopharyngioma (CP) and to identify tumor characteristics and other factors influencing these alterations, including changes in the lesion’s location. Design: retrospective clinical cohort study. Methods: A retrospective analysis was conducted on 73 eyes from 38 patients with CP and 64 eyes from 32 age- and sex-matched healthy controls. The mean age of the CP patients was 10.3 ± 4.2 years (range 4–17), while the control group had a mean age of 10.5 ± 3.1 years (range 4–17). Optical coherence tomography (OCT) was used to assess the peripapillary RNFL thickness in the study and control groups. RNFL thickness was analyzed in the superior, inferior, and average sectors, as well as across eight optic nerve sectors. Tumor characteristics were evaluated to determine their correlation with changes in RNFL thickness in individual sectors. Results: Postoperative thickness of peripapillary RNFL in all individual sectors was significantly reduced in the CP group compared to healthy controls. Location, tumor volume, maximum tumor diameter, calcification, ventriculoperitoneal shunt, surgery technique, total resection, presence of Rosenthal fibers, and reoperation due to progression or recurrence correlated with damage to RNFL. Conclusions: CP is associated with significant reductions in RNFL thickness, indicating the tumor’s impact on optic nerve fibers. OCT is a valuable tool for monitoring visual pathway impairment and postoperative outcomes. Correlations between RNFL thickness in individual sectors and clinical parameters may offer valuable insights for diagnosis and monitoring, underlining their potential role in predicting visual outcomes. Regular RNFL evaluation should be integrated into the long-term care of CP patients to optimize visual prognosis and detect progressive or residual damage. Full article

Alpha2-plasmin inhibitor (α2PI) has a heterogeneous structure due to proteolytic cleavages in the circulation. The C-terminally cleaved form loses the plasminogen binding site and is, therefore, a slow plasmin inhibitor (NPB-α2PI). As FXIII primarily crosslinks the plasminogen-binding intact form (PB-α2PI) to fibrin, the effect of NPB-α2PI on fibrinolysis has been less studied. Herein, we investigated the effect of C-terminal truncation. Total-, PB-, and NPB-α2PI antigen levels and α2PI incorporation were measured by ELISAs from samples of 80 healthy individuals. Clot lysis parameters of the same subjects were investigated using an in vitro clot lysis assay. α2PI incorporation into the clot was demonstrated by Western blotting. Clot lysis and clot structure were also analyzed using an α2PI-deficient plasma substituted with recombinant PB- and NPB-α2PI. Both plasma and clot-bound levels of total- and NPB-α2PI showed a significant positive correlation with clot lysis parameters. NPB-α2PI was detected in the clot due to non-covalent binding. Regardless of the type of binding, both forms affected the clot structure by increasing the thickness of the fibrin fibers and reducing the pore size. In conclusion, we found that NPB-α2PI can bind non-covalently to fibrin, and this binding contributes to changes in clot structure and inhibition of fibrinolysis. Full article

To improve the efficiency and stability of the system, this paper proposes a monolithic integrated optical path design for a cavity optomechanical accelerometer based on a 250 nm top silicon thickness silicon-on-insulator (SOI) wafer instead of readout through U-shape fiber coupling. Finite Element Analysis (FEA) and Finite-Difference Time-Domain (FDTD) methods are employed to systematically investigate the performance of key optical structures, including the resonant modes and bandgap characteristics of photonic crystal (PhC) microcavities, transmission loss of strip waveguides, coupling efficiency of tapered-lensed fiber-to-waveguide end-faces, coupling characteristics between strip waveguides and PhC waveguides, and the coupling mechanism between PhC waveguides and microcavities. Simulation results demonstrate that the designed PhC microcavity achieves a quality factor (Q-factor) of 2.26 × 10⁵ at a 1550 nm wavelength while the optimized strip waveguide exhibits a low loss of merely 0.2 dB over a 5000 μm transmission length. The strip waveguide to PhC waveguide coupling achieves 92% transmittance at the resonant frequency, corresponding to a loss below 0.4 dB. The optimized edge coupling structure exhibits a transmittance of 75.8% (loss < 1.2 dB), with a 30 μm coupling length scheme (60% transmittance, ~2.2 dB loss) ultimately selected based on process feasibility trade-offs. The total optical path system loss (input to output) is 5.4 dB. The paper confirms that the PhC waveguide–microcavity evanescent coupling method can effectively excite the target cavity mode, ensuring optomechanical coupling efficiency for the accelerometer. This research provides theoretical foundations and design guidelines for the fabrication of high-precision monolithic integrated cavity optomechanical accelerometers. Full article

Glass fiber-reinforced polymer (GFRP) composites exhibit significant advantages over conventional structural webbing materials, including lightweight and corrosion resistance. This study investigates the localized compression performance of the proposed GFRP grid web–concrete composite beam through experimental and numerical analyses. Three specimen groups with variable shear-span ratios (λ = 1.43, 1.77) and local stiffener specimens were designed to assess their localized compressive behavior. Experimental results reveal that a 19.2% reduction in shear-span ratio enhances ultimate load capacity by 22.93% and improves stiffness by 66.85%, with additional performance gains of 77.53% in strength and 94.29% in stiffness achieved through local stiffener implementation. In addition, finite element (FE) analysis demonstrated a strong correlation with experimental results, showing less than 5% deviation in ultimate load predictions while accurately predicting stress distributions and failure modes. FE parametric analysis showed that increasing the grid thickness and decreasing the grid spacing within a reasonable range can considerably enhance the localized compression performance. The proposed analytical model, based on Winkler elastic foundation theory, predicts ultimate compression capacities within 10% of both the experimental and numerical results. However, the GFRP grid strength adjustment factor β_g should be further refined through additional experiments and numerical analyses to improve reliability. Full article

This research aims to offer a deep learning-based diagnostic approach for hemorrhagic complications linked to patent ductus arteriosus (PDA) in preterm infants. Utilizing the You Only Look Once (YOLO) algorithm, this research analyzed five key cardiac parameters derived from echocardiographic ultrasonic waves: the left ventricular ejection time (LVET), left ventricular internal dimension at diastole (LVIDd), left ventricular internal dimension at systole (LVIDs), posterior wall thickness at end-systole (HES), and RR interval between two successive R-waves. The proposed ensemble model achieved best-in-class detection accuracies for each parameter, with rates of 97.56% (LVET), 88.69% (LVIDd), 99.50% (LVIDs), 82.29% (HES), and 81.15% (RR interval). Furthermore, assessment of cardiac function using derived indices—end-systolic wall stress (ESWS) and rate-corrected mean velocity of circumferential fiber shortening (mVcfc)—achieved mean accuracy rates of 82.33% and 90.16%, respectively. This approach enables physicians to accurately evaluate cardiac function in preterm infants and facilitates the diagnosis of PDA-related hemorrhagic complications. Full article

To meet the rapid maneuverability and lightweight demands of micro-nano satellites, a space micro solid thruster using 3D-printed short glass fiber reinforced polyamide 6 (PA6GF) composites was developed. Thruster shells with wall thicknesses of 4, 3, and 2.5 mm were designed, and ground ignition tests were conducted to monitor chamber pressure and shell temperature. Compared with conventional metallic thrusters, PA6GF composites have exhibited excellent thermal insulation and sufficient mechanical strength. Under 8 MPa and 2773 K ignition conditions, the shell thickness was reduced to 2.5 mm and could withstand pressures up to 10.37 MPa. These results indicate that PA6GF composites are well-suited for space micro solid thrusters with inner diameters of 15–70 mm, offering new possibilities for lightweight space propulsion system design. Full article

Fiber Bragg grating (FBG) exhibits strong resistance to electromagnetic interference and excellent linear strain response, making it highly promising for structural health monitoring (SHM) in pavement. This research investigates the strain transfer characteristics of embedded FBG in pavement structure and materials by using the relevant theoretical models. Results indicate adhesive layer thickness and sheath modulus are the primary factors influencing the strain transfer coefficient. A thinner adhesive layer and high modulus of sheath enhance the coefficient. Additionally, the strain distribution of sheath significantly affects the transfer efficiency. When the stress level near the grating region is lower than the both ends, the coefficient increases and even exceeds 1, which typically occurs under multi-axle conditions. As for asphalt mixture, high temperature leads to lower efficiency, while accumulated plastic strain improves it. Although the increased load frequency results a higher strain transfer coefficient, the magnitude of this change is negligible. By employing polynomial fitting to the sheath strain distribution, the boundary condition of theoretical equation could be removed. The theoretical and numerical results of strain transfer coefficient for pavement embedded FBG demonstrate good consistency, indicating the polynomial fitting is adoptable for the theoretical calculation with non-uniform strain distribution. This study utilizes the FEM to clarify the evolution of FBG strain transfer in pavement structures and materials, providing a theoretical basis for the design and implementation of embedded FBG in pavement. Full article

CFRP possesses the advantages of lightweight and high strength, but its cost is relatively high, and its ductility is insufficient; aluminum alloys have a relatively low cost and good ductility. This paper develops a CFRP-aluminum alloy laminated tube (CFRP-AL tube), which combines the advantages of CFRP and aluminum alloy. Such composite components have broad application prospects in the field of spatial structures. The CFRP-AL tubes were studied by experimental, numerical, and theoretical research on their axial compression performance in this paper. Firstly, the standard tensile test was carried out on 6061-T6 aluminum alloy. Combining the test results and references, the Johnson–Cook hardening model parameters of aluminum alloy were determined. The tensile test of CFRP was conducted to determine its material parameters. Based on composite material mechanics and fracture mechanics, a composite progressive damage model for the CFRP-AL tube was established. Secondly, axial compression tests were carried out on 27 CFRP-AL tubes and 3 aluminum alloy tubes with a small slenderness ratio. The test results show that the typical failure mode of CFRP-AL tubes with small slenderness ratios is strength failure, and the ultimate bearing capacity rises by 11~31% compared to aluminum alloy tubes. Thirdly, a user material subroutine capable of simulating CFRP failure was developed. Based on the user material subroutine, the effect of the initial imperfection, the fiber layer angle, the fiber layer thickness, the slenderness ratio, the diameter-thickness ratio and the CFRP volume ratio were discussed. And the failure mechanism and response of the CFRP-AL tubes under the axial compression were obtained. Finally, based on the strength theory, the formula predicting the bearing capacity of the strength failure was established, and the results of the formula were in a good agreement with the experimental and numerical results. Full article

The aim of this paper is to present our experience with the diagnosis and management of nine patients diagnosed with Leber’s hereditay optic neuropathy. Materials and methods: We conducted a prospective, observational study that included nine patients treated with idebenone, followed for a period of 18 months. Results: Our findings suggest that the impact of treatment varies significantly depending on the disease phase. In the acute phase, visual acuity deteriorated from 0.67 logMAR at onset to 0.97 logMAR at 3 months, followed by a slight improvement to 0.88 logMAR at 9 months. In the chronic phase, average values decreased progressively from 1.44 logMAR at onset to 1.26 logMAR at 12 and 18 months. We also observed a consistent treatment benefit over time in eyes harbouring the m.11778 G > A mutation. Although the most powerful predictor of visual outcome remains the mtDNA genotype, young age at onset is correlated with a better prognosis. In the acute phase, more cases of a clinically relevant benefit were observed than expected (33.33% versus 22.22% expected), and fewer clinically relevant worsening cases were observed (0% versus 11.11% expected). Regarding OCT measurement, our study highlighted a significant difference in peripapillary retinal nerve fiber layer thickness between the initial evaluation and the 6-month follow-up (100.83 µm ± 30.2 at baseline versus 96.7 µm ± 24.8 at 6 months). Conclusions: Our paper demonstrates the benefit of idebenone treatment in improving visual acuity in patients with Leber hereditary optic neuropathy. We highlighted the importance of long-term treatment, emphasizing that extended administration is key to achieving favorable outcomes. Full article

The standardization of physical and mechanical properties is critical for the large-scale application of engineered bamboo products. In this study, the distribution characteristics of density and modulus of elasticity (MOE) were systematically examined in a large sample of flattened bamboo boards. The density and MOE ranged from 0.46 to 1.12 g/cm³ and 5.60 to 22.18 GPa, respectively. Both exhibited a decreasing trend with increasing board thickness. Based on interquartile analysis, four density grades and five MOE grades were established. A strong positive correlation was identified between density and MOE, indicating that density—closely linked to fiber volume fraction—is the primary factor influencing mechanical performance. Notably, the graded bamboo boards demonstrated significantly higher modulus values than conventional wood veneers such as hemlock and poplar, highlighting their potential for high-performance structural applications. This study proposes a practical grading framework that contributes to the standardization and broader engineering utilization of flattened bamboo boards. Full article

In this study, the optimal design of the central pipe in a middle-deep geothermal heat pump (MD-GHP) system is studied using the response surface method to improve the system’s coefficient of performance (COP) and operational reliability. Firstly, a model describing the energy transfer and conversion mechanisms of the MD-GHP system, incorporating unsteady heat transfer in the central pipe, is established and validated using field test data. Secondly, taking the inner diameter, wall thickness, and effective thermal conductivity of the central pipe as design variables, the effects of these parameters on the COP of a 2700 m deep MD-GHP system are analyzed and optimized via the response surface method. The resulting optimal parameters are as follows: an inner diameter of 88 mm, a wall thickness of 14 mm, and an effective thermal conductivity of 0.2 W/(m·K). Based on these results, a composite central pipe composed of high-density polyethylene (HDPE), silica aerogels, and glass fiber tape is designed and fabricated. The developed pipe achieves an effective thermal conductivity of 0.13 W/(m·K) and an axial tensile force of 29,000 N at 105 °C. Compared with conventional PE and vacuum-insulated pipes, the composite central pipe improves the COP by 11% and 7%, respectively. This study proposes an optimization-based design approach for central pipe configuration in MD-GHP systems and presents a new composite pipe with enhanced thermal insulation and mechanical performance. Full article

The current study demonstrates the buckling properties of composite laminates reinforced with MWCNT fillers using a novel higher-order shear and normal deformation theory (HSNDT), which considers the effect of thickness in its mathematical formulation. The hybrid HSNDT combines polynomial and hyperbolic functions that ensure the parabolic shear stress profile and zero shear stress boundary condition at the upper and lower surface of the plate, hence removing the need for a shear correction factor. The plate is made up of carbon fiber bounded together with polymer resin matrix reinforced with MWCNT fibers. The mechanical properties are homogenized by a Halpin–Tsai scheme. The MATLAB R2019a code was developed in-house for a finite element model using C⁰ continuity nine-node Lagrangian isoparametric shape functions. The geometric nonlinear and linear stiffness matrices are derived using the principle of virtual work. The solution of the eigenvalue problem enables estimation of the critical buckling loads. A convergence study was carried out and model efficiency was corroborated with the existing literature. The model contains only seven degrees of freedom, which significantly reduces computation time, facilitating the comprehensive parametric studies for the buckling stability of the plate. Full article