Search Results (1,412)

This study presents a combined numerical–statistical framework based on the Extended Finite Element Method (XFEM) and the Taguchi optimization method to assess the fracture behavior of pressurized pipelines containing external longitudinal cracks. XFEM is employed to evaluate the local fracture response without remeshing, while the Taguchi method is used to quantify the influence of key parameters and identify an optimal configuration with a limited number of simulations. The control parameters considered are internal pressure, initial crack length, and wall thickness, and the evaluated mechanical responses include circumferential stress, the J-integral, and the stress intensity factor. The optimization follows the “smaller-the-better” criterion to minimize stress concentration, fracture-driving forces, and the risk of structural failure. Results indicate that internal pressure predominantly affects circumferential stress and the stress intensity factor, whereas wall thickness has the greatest influence on the J-integral. The optimal parameter combination is determined through signal-to-noise ratio analysis and validated using the delta method, confirming the robustness of the selected configuration. A confirmation simulation performed with XFEM demonstrates a consistent reduction in all fracture-related mechanical responses, highlighting the effectiveness of the proposed approach. It should be noted that the present study is limited to the static fracture assessment of external cracks and does not address fatigue crack growth or fatigue life prediction. Overall, the proposed methodology provides a decision-support tool for pipeline integrity management by integrating numerical fracture mechanics analysis with robust design optimization, thereby contributing to safer operation and improved structural reliability. Full article

Buried steel pipelines are susceptible to external pitting corrosion whose spatially heterogeneous and time-dependent nature makes probabilistic remaining useful life (RUL) estimation both necessary and difficult. This study develops a three-stage framework comprising statistical pit depth characterization, a proxy corrosion-growth learner, and a mechanics-regularized limit-state RUL model anchored to the modified B31G burst criterion and an auxiliary conservative depth-screen rule, in which a corrosion-growth prior learned from sparse field measurements is embedded directly into the learning objective as a regularizer rather than merely used to construct training labels, and conformal calibration is applied at both the proxy and the limit-state stages to ensure honest empirical coverage, with the mechanics-regularized limit-state model consistently achieving coverage close to or above the nominal 90% target. Applied to the Velázquez excavation dataset and further examined on a 127-sample engineering database used as an auxiliary transferability check, the framework delivered stable point accuracy across all three wall thickness scenarios while maintaining empirical 90% coverage consistently above the nominal target. These results demonstrate that embedding mechanics-based growth constraints into the learning objective improves predictive consistency under sparse field data, while the resulting reliability outputs are best interpreted as scenario-based screening evidence for comparative integrity prioritization rather than as literal asset-life certification. Full article

The production process of hot-rolled seamless steel tubes often needs secondary heating for tempering treatment, resulting in high energy consumption and low production efficiency. Controlled cooling technology has been introduced into the production process. By controlling the self-tempering temperature, the residual temperature of the steel tubes is used to realize self-tempering, so as to achieve the purposes of energy savings, emissions reduction, cost reduction, and efficiency increase. This study investigated the evolution of temperature and stress fields in a seamless steel tube during temperature-controlled quenching. The size of the steel tube is 140 mm × 20 mm × 200 mm. The outer-wall cooling intensity and the self-tempering temperature were selected as the main variables, and the other process parameters remained constant. The temperature distribution and stress variation curves under different cooling intensities were obtained. The results showed that the greater the cooling intensity of the outer wall, the higher the temperature recovery of the outer wall. Under the fixed cooling intensity, the lower the self-tempering temperature, the lower the return temperature. In the thickness direction of the steel tube, there is a stress distribution of “internal tension and external compression”. Moreover, the greater the cooling intensity, the lower the self-tempering temperature and the greater the residual stress. Full article

Hydronephrosis caused by malignant ureteral obstruction or radiotherapy-induced ureteral stenosis is a frequent complication in patients with cervical cancer. Effective management requires continuous urinary drainage, which can be achieved either internally through ureteral stent placement or externally via percutaneous nephrostomy. Among available devices, the Allium^TM fully covered nitinol mesh ureteral stent is designed to treat ureteral or urethral strictures while allowing safe and easy removal. However, serious complications have been reported, including uretero-enteric, uretero-arterial, and uretero-vaginal fistulas, pseudoaneurysm, ureteral perforation and sepsis. We report the case of a 44-year-old woman diagnosed in 2020 with stage IIIC1 cervical cancer (FIGO classification) who underwent surgery followed by adjuvant radiotherapy. In 2021, a right metallic ureteral stent was placed to treat ureteral obstruction. Two years later, she presented with right lumbar pain, and abdominal ultrasonography revealed grade III right hydronephrosis. CT scan demonstrated migration of the metallic ureteral stent into the rectal wall. Endoscopic extraction of the migrated stent was successfully performed via colonoscopy. Retrograde pyelography and CT imaging confirmed the presence of a recto-ureteral fistula. A 6 Ch/26 cm double-J ureteral stent was subsequently placed with good positioning and drainage. At the six-month follow-up, replacement of the double-J stent was performed. Imaging studies showed only minor residual hydronephrosis. Although metallic ureteral stents are effective for managing malignant ureteral obstruction, particularly in complex oncologic cases, they are not free of severe complications. The risk appears increased in patients who have undergone radiotherapy, emphasizing the need for careful monitoring and long term follow-up. Full article

The eco-revetment structure on river bank slopes plays a positive role in regulating nearshore water flow characteristics, enhancing bank slope stability, and providing a stable living environment for aquatic organisms. This study proposes an innovative eco-revetment structure—the square platform hollow eco-revetment structure. Ecological feasibility study through numerical simulation, analyzing the characteristic hydraulic movement patterns and flow movement mechanisms near the eco-revetment structure under different research parameters. The following conclusion can be drawn: the special design of openings on the side walls of the revetment structure increases the fluidity between water bodies, leading to complex water flow conditions near the revetment structure. Therefore, in the absence of plants, there are two large eddies inside the structure, as well as a “flow zone” opposite to the direction of external water flow. In the presence of plants, large-scale vortex structures are broken down into small-sized vortex structures, and the “flow zone” disappears. The distribution of flow characteristics is related to the research parameters. In the region where y/H ≤ 1, the velocity distribution is positively correlated with the inflow. There is a negative correlation between water flow velocity and porosity. The maximum values of turbulence intensity and Reynolds stress both occur at the top of the eco-revetment structure, and their distribution is positively correlated with the size of the side-wall openings and the inflow rate. The presence of plants leads to an increase in turbulence intensity and Reynolds stress, which diffuses into the interior of the structure. The impact of revetment structures on water flow determines the efficiency of material information and energy transmission and affects the stability of water flow ecosystems. Turbulent water currents can stimulate grass carp reproduction and increase the fertilization rate of fish eggs. The ratio of mixed-layer thickness to momentum thickness (t_ml/θ) is correlated with water flow velocity, and the presence of plants leads to an increase in t_ml/θ. This study provides ideas and methods for designing eco-revetment structures and constructing ecological rivers in the future. Full article

Objectives: Commercial artificial teeth (AT) and three-dimensional printed teeth (3DPT) have been increasingly used in preclinical endodontic education; however, limitations regarding anatomical realism, tactile sensation, and procedural simulation continued to be reported. This study assessed students’ and evaluators’ perceptions regarding AT and PolyJet™ 3DPT fabricated with RGD525™, compared with natural teeth (NT), together with the quality of endodontic procedures performed using both artificial models. Methods: Undergraduate dental students with no previous experience using AT or 3DPT performed standardized endodontic procedures on both artificial models. Students and evaluators completed questionnaires regarding anatomical realism, tactile sensation, radiographic characteristics, educational applicability, and model preference. Procedural quality and errors were independently assessed radiographically by evaluators. Results: AT received more favorable perceptions regarding external anatomy, whereas 3DPT were more positively evaluated for internal anatomy, radiopacity, resistance of root canal walls and tactile sensation during instrumentation (p ≤ 0.002). NT remained the preferred training model, followed by 3DPT, while AT received the lowest preference ratings (p < 0.001). Evaluators consistently perceived 3DPT as more similar to NT than AT. Regarding treatment outcomes, 3DPT showed significantly higher scores for endodontic preparation, verifier fitting, and root canal filling (p < 0.05), while presenting significantly fewer procedural errors than AT (p < 0.001). Conclusions: PolyJet™ 3DPT fabricated with RGD525™ demonstrated promising applicability for preclinical endodontic training, combining favorable perceptions, fewer procedural errors, and potential for low-cost large-scale in-house production. Nevertheless, improvements in material realism and tactile simulation are still required. Full article

Purpose: To develop a fully automated 2D nnU-Net pipeline for multi-class skeletal muscle segmentation (psoas, paraspinal, and abdominal wall) at the third lumbar (L3) vertebral level, and to quantitatively evaluate its diagnostic performance and reliability compared to manual segmentation. Materials and Methods: A 2D nnU-Net was trained on 164 axial L3 CT slices from the multi-institutional AMOS22 dataset, spanning diverse abdominal pathologies and multivendor imaging. To assess generalizability under severe anatomical distortion, independent external validation was performed in 50 consecutive patients with advanced liver disease from a single institution (January–December 2025; mean age, 63 ± 15 years; 32 women, 18 men), of whom 88% had moderate-to-severe ascites. Model stability was examined by comparing a five-fold ensemble with the best-performing single-fold model. Intra-observer reliability of the manual reference standard was evaluated in a random subset of 30 cases. Inter-observer agreement was additionally assessed using an independent second reader. Performance metrics included the Dice Similarity Coefficient (DSC), Pearson correlation coefficient (r), and Bland–Altman analysis for cross-sectional areas and mean attenuation. The inference workflow was deployed via a custom Streamlit-based graphical user interface (GUI). Results: In this anatomically complex external validation cohort, the 5-fold ensemble 2D nnU-Net achieved an overall mean DSC of 0.937 ± 0.043 (95% CI, 0.925–0.950), with 80% of cases achieving a mean DSC ≥ 0.90. While the mean DSC was statistically comparable to the best single-fold model (0.937, [95% CI, 0.921–0.952], p = 0.736), the ensemble strategy increased the minimum observed DSC (worst-case performance) from 0.720 to 0.822. Class-specific external validation performance for the 5-fold ensemble was highest for the paraspinal muscles (DSC: 0.960; 95% CI, 0.952–0.967), followed by the psoas muscles (DSC: 0.941; 95% CI, 0.927–0.956), and lowest for the anatomically complex abdominal wall muscles (DSC: 0.911; 95% CI, 0.893–0.929). Comparison between the ensemble model and manual segmentation yielded a Pearson correlation of r = 0.955 (p < 0.001) for total skeletal muscle area, with a mean bias of +7.17 cm². Intra- and inter-observer agreements for the manual reference standard demonstrated correlation coefficients of r = 0.995 and 0.090 for total areas, respectively. The automated pipeline required 3–5 s per case for inference and quantitative reporting, compared to 3–5 min for manual segmentation. Conclusions: In patients with advanced liver disease and substantial anatomical distortion from ascites, an ensemble-based 2D nnU-Net provides high quantitative agreement with manual L3 skeletal muscle segmentation, while mitigating lower-bound (worst-case) errors relative to single-fold models. Integration with a dedicated GUI enables substantial time savings and supports scalable quantitative body composition measurement. Full article

Accurate knowledge of the thermal transmittance (U-value) of existing building envelopes is essential for reliable energy performance assessment and the planning of energy-efficient refurbishment measures. However, in practice, the material composition of existing walls is often unknown, and installing measurement devices may be restricted due to limited accessibility, the risk of structural damage, or varying on-site boundary conditions. Although several in situ methods for determining the U-value have been proposed in the literature, systematic comparisons of their performance under real environmental conditions remain limited. This lack of comparative evaluation makes it difficult to select the most appropriate method under specific practical constraints. To address this gap, this study presents a comprehensive experimental comparison of four in situ U-value measurement methods applied simultaneously to the same building element under identical real boundary conditions, providing new insights into their accuracy, uncertainty, and practical applicability. In this study, four in situ techniques commonly used to determine the thermal transmittance (U-value) were tested on a double-leaf brick wall at the University of Stuttgart: heat flow meter (HFM), infrared thermography (IRT), infrared thermometer (IRTM), and thermometric method (THM). The measurements were carried out over several days under real boundary conditions, during which air temperature, surface temperature, and heat flux were recorded at regular intervals. The results show that all four techniques can be reliably used under real boundary conditions, with the measured U-values lying within a comparable range. Differences among the methods were observed, largely due to their varying sensitivity to environmental influences and sensor placement. A comparison between the upper and lower parts of the wall indicated that its thermal response is non-uniform, and the observed deviations can be attributed to its inhomogeneous structure. By outlining the strengths and limitations of each technique and comparing their measurement outcomes, this study provides practical guidance for selecting suitable approaches for in situ U-value determination. Furthermore, the findings support future efforts to refine thermal evaluation methods and improve energy performance in existing buildings. Full article

Rapid vertical growth in Tier-2 Indian cities is reshaping residential forms and may affect cooling demand, passive comfort, overheating severity, and peak electricity demand. This study examines the influence of building height and window-to-wall ratio (WWR) on residential thermal performance in Patna, India, a composite-climate context. Five archetypes–detached house, row-house, low-rise apartment, mid-rise apartment, and high-rise apartment–were simulated in DesignBuilder/EnergyPlus Version 23.1.0 under 20%, 30%, and 40% WWR scenarios. Passive and active operation modes were evaluated through 30 annual simulations, generating 262,800 hourly records. External shading was excluded, and occupancy and ventilation assumptions were standardized to create a controlled benchmark design. Performance was assessed using annual cooling energy demand (ACED), all-hour and occupied-hour passive comfort percentage, adaptive degree-hours (ADH), and peak demand indicators. At 20% WWR, ACED increased from 33.13 kWh/m²·yr in the low-rise archetype to 42.79 kWh/m²·yr in the high-rise archetype, while all-hour passive comfort decreased from 68.16% to 49.28%. The row-house archetype performed best due to reduced exposed envelope area. A second-order surrogate model provided exploratory scenario-level approximation across 15 archetype–WWR cases. The findings support further investigation of morphology-sensitive residential envelope guidance within bounded composite-climate benchmark conditions. Full article

A broadband method for measuring the complex permeability of thin magnetic films using a short-circuited microstrip fixture is presented. The method is based on full one-port offset-short calibration implemented directly in the fixture with a movable shorting wall, reducing sensitivity to coaxial-to-strip transition imperfections and eliminating the need for its precise optimization. Field-dependent normalization to the empty fixture reduces systematic errors from the external magnetic field, and a correction for residual saturated permeability improves retrieval accuracy. The method was validated on Co, supermalloy, and FeCo films on flexible PET substrates. Retrieved spectra agreed well with reference coaxial data and with the spectrum reconstructed from static magnetic measurements. In the present implementation, broadband spectra were obtained from 0.1 to 20 GHz with no significant systematic distortion, indicating that the proposed approach is suitable for accurate broadband characterization of thin magnetic films without reference standards or precise optimization of the coaxial-to-strip transition. Full article

The deployment of object detection models on resource-constrained edge devices remains a substantial challenge, primarily because conventional static networks expend the same worst-case computational cost on every input, regardless of intrinsic difficulty. This paper proposes an input-adaptive dynamic neural network architecture for object detection in embedded environments. The present study investigates two orthogonal axes of input-adaptive inference for embedded object detection: The system demonstrates depth adaptivity through the implementation of Early Exit, and width adaptivity via group-wise Adaptive Routing. The proposed framework is constructed on a frozen Ultralytics YOLO26s backbone and incorporates two YOLO-style early-exit heads positioned at approximately 33% and 66% of the backbone depth. Furthermore, the framework incorporates two Straight-Through Gumbel-Softmax routers, which are appended after Layers 4 and 8 with group-wise hard gating. Both axes additionally accept an explicit external control signal that allows the host system to override the input-conditional policy at inference time. The dual-mode design facilitates the functionality of the trained checkpoint as either an input-adaptive policy, in which the depth and width are determined per sample from the input distribution, or an externally controlled policy. The experimental findings demonstrate two strongly asymmetric input-adaptive policies on a frozen YOLO26s backbone. The early-exit profile reduces the compute per sample from 12.739 to 10.532 GFLOPs—a 17.32% reduction according to our in-house Conv2d/Linear MAC-based GFLOPs estimator—while preserving baseline accuracy (mAP50 = 0.1545 vs. baseline = 0.1528; ΔmAP50 = +0.0017, within evaluation noise; mAP50–95 = −0.0033). Evaluating the router-only profile in the same validator pipeline with a sparsity penalty of γ = 0.05 results in a 12.3% decrease in logical GFLOPs (from 12.739 to 11.172), while maintaining an accuracy level that is at or above the PEFT baseline (mAP50 = 0.2324 and mAP50–95 = 0.1040). In our small-domain PEFT setup, training the dynamic-policy modules yields per-checkpoint mAP shifts in this magnitude. Therefore, we interpret the width-axis accuracy result as preservation of the baseline rather than an improvement. Our contribution on the width axis is reducing computing power while maintaining baseline accuracy. Importantly, the router profile’s logical GFLOP savings are not currently reflected in wall-clock latency under our dense-kernel PyTorch implementation. Achieving practical speedup requires sparse-kernel deployment, such as structured-sparse kernels, TensorRT, TVM, or Triton paths. We will address this in future deployment-level work. Our results indicate that the depth axis can yield genuine end-to-end speedup today, while the width axis offers deployment-pending compute reduction. Full article

This article presents a multi-criteria comparative analysis of modern wall partitions in light-frame technology, with a focus on highly energy-efficient modular construction. The motivation for this research stems from the critical need to optimize building thermal insulation materials to minimize heat loss, while simultaneously ensuring low structural weight, rapid assembly, and hygrothermal safety in prefabricated systems. The aim of this study is to identify the most advantageous insulating materials and structural configurations by evaluating their thermal transmittance, moisture behavior, thermal dynamics, and fire resistance. The analysis encompassed four structural variants paired with seven types of advanced and conventional insulation materials. This comprehensive matrix allowed for the development of 28 computational models. Simulations were carried out for severe winter climatic conditions in Poland, utilizing the Ubakus software and conforming to the PN-EN ISO 13788, PN-EN ISO 6946, PN-EN 12524, and DIN 4108-3 standards. The simulations assumed strict steady-state boundary conditions for a 90-day condensation period, with an external profile of −14 °C/80% RH and an internal climate of 20 °C/50% RH. The evaluation focused on key physical and energy parameters, including the heat transfer coefficient (U-value), condensation risk, diffusion resistance, thermal phase shift, and partition weight. Quantitative findings reveal that the ventilated system with resol foam insulation (variant 4d) yielded the best overall performance, achieving a U-value of 0.089 W/(m²·K) W/(m²·K). The results confirm that the strategic selection of high-performance thermal insulation materials, coupled with structural thermal bridge mitigation, significantly enhances the energy efficiency, thermal stability, and moisture resistance of lightweight enclosures, establishing a comprehensive comparative framework for optimizing modular building envelopes. Full article

Rapid, accurate, and scalable ion sensing technologies are highly desirable for future flexible healthcare and lab-on-a-chip applications. Here, we present a fully roll-to-roll (R2R) gravure-printed single-walled carbon nanotube complementary ring oscillator (SWCNT-cRO)-based microfluidic ion sensing platform fabricated on a flexible substrate. The proposed platform combines scalable printed complementary electronics with frequency-based ion sensing via electrostatically induced top-gating in aqueous microfluidic environments. The fabricated SWCNT-cRO devices exhibited stable oscillation characteristics, with a high device yield (>80%) and continuous manufacturing capability at a web speed of 5.4 m/min. Printable ethanolamine/zirconium acetylacetonate-based n-doping technology enabled complementary SWCNT transistor operation, while multilayer CYTOP/FG-3650 encapsulation ensured stable electrical operation under ionic aqueous conditions. After integration into a polydimethylsiloxane-based microfluidic channel, the oscillation frequency of the SWCNT-cRO was systematically modulated by Na⁺ concentration and pH. The sensing mechanism was based on electrostatically induced carrier modulation in n-type SWCNT transistors, resulting in variations in propagation delay and corresponding shifts in oscillation frequency. Compared with conventional ion-sensitive transistor platforms, the proposed approach offers scalable manufacturing, non-contact ion sensing, elimination of external reference electrodes, and direct compatibility with digital frequency-signal processing systems. This work establishes a promising strategy for future low-cost, disposable, and flexible microfluidic sensing platforms for wearable healthcare and lab-on-a-chip applications, ion sensing, and thin-film transistors. Full article

In slab continuous casting, the internal hydrodynamics of the submerged entry nozzle (SEN) play a determining role in mold flow stability and product quality, particularly when external electromagnetic flow-control technologies are not employed. This study analyzes a novel bifurcated SEN design intended to promote stable, highly symmetric outlet jets under asymmetric inlet flow conditions produced by typical flow-control devices. The proposed configuration combines three geometric modifications: a square-section bore, a flow-divider bottom wall derived from a rotated mountain-type geometry, and two bell-shaped protrusions that act as flow modulators positioned immediately above the outlet ports. The hydrodynamic behavior inside the nozzle was investigated using complementary experimental and numerical approaches. Physical modeling was conducted in a scaled water model using particle image velocimetry (PIV) to characterize time-averaged velocity fields and flow fluctuations. In parallel, three-dimensional large-eddy simulations (LESs) were performed to resolve transient flow structures and quantify jet characteristics at the nozzle exits. Both approaches show consistent results. The combined action of the flow modulators and the flow-divider bottom wall robustly induces the formation of two nearly identical counter-rotating vortices in the lower region of the SEN. This flow structure suppresses stagnation and recirculation zones near the outlet ports, mitigates inlet-induced asymmetries, and enhances flow evacuation efficiency. Quantitative analysis of the outlet jets indicates a significant reduction in angular dispersion and a flow-rate imbalance below 0.2%, markedly lower than that observed in conventional SEN configurations. The results demonstrate that appropriate internal geometric design can effectively stabilize SEN hydrodynamics without active control systems, offering a feasible and scalable strategy for improving mold flow stability in industrial continuous casting operations. Full article

The study proposes and investigates a seismic retrofitting strategy based on an external reinforced concrete exoskeleton, grounded in the analysis of the actual force transfer mechanisms between the existing structure and the added system. The three-dimensional numerical model was developed in ETABS, employing linear response spectrum analysis in accordance with EN 1998-1 and P100-1/2013. The internal forces transmitted at the structural interface were determined using the Section Cut method, enabling the identification of integrated resultants and the prioritization of critical connections. Three types of connections are examined—slab-to-slab, column-to-wall, and beam-to-joint—while the distribution of stresses within the anchor groups is assessed based on an elastic model under combined axial force and bending action. The results indicate that the global structural response is governed by diaphragm coupling, whereas the vertical interfaces ensure kinematic compatibility and the redistribution of axial and bending effects. The proposed methodology provides a coherent framework for the rational design of interface connections in retrofit interventions carried out without interrupting building operation. Full article