Local Defects Research Articles

Evaluation of multiple ventricular septal defects using three-dimensional reconstruction models

Abstract OBJECTIVES Although there has been rapid development in the field of three-dimensional morphological analyses of congenital heart disease, with the three-dimensional volume-rendered images providing visualization of the external vascular anatomy, the precise reproduction of “Swiss-cheese” ventricular septum is not well established. We created three-dimensional printed models and computer graphics based on multi-slice computed tomography of patients with complex multiple ventricular septal defects for surgical decision planning of this difficult cardiac defect. METHODS Seven patients with complex multiple ventricular septal defects were evaluated preoperatively using three-dimensional printed models and computer graphics to plan therapeutic interventions. RESULTS The three-dimensional printed models detected muscular VSDs in 9 out of 15 (60%) regions. On the other hand, Three-dimensional computer graphics detected 10 out of 15 (67%) regions. The three-dimensional printed models and computer graphics allowed the evaluation of the muscular ventricular septal defects from both the left and right ventricular aspects of the septum. CONCLUSIONS Our preliminary experiences suggest that three-dimensional printed models and computer graphics can help plan surgery in patients with complex multiple ventricular septal defects. Three-dimensional printed models allowed surgeons to understand the three-dimensional positioning of complex multiple ventricular septal defects preoperatively. High-quality three-dimensional computer graphics provided precise information about the size, shape and localization of muscular ventricular septal defects especially from the left ventricular side.

Impact of localized defects in light scattered by optical components: measurement and analysis

Impact of localized defects in light scattered by optical components: measurement and analysis

Research on modulation mechanisms of cantilever-structured phononic crystals integrating piezoelectric effects and localized defects

Abstract Controlling vibrations with varying frequencies is key to improving the riding comfort of vehicles. Thus, this paper studies cantilever-structured piezoelectric Phononic Crystals with tunable defect frequency within the low-frequency bandgap. Firstly, this paper proposes cantilever-structured piezoelectric Phononic Crystals, which is proven to possess a low-frequency bandgap of 310 Hz-395 Hz through the plane wave expansion method, finite element simulation, and experiments. Subsequently, by establishing a numerical model, performing finite element simulations, and conducting sample experiments, the mechanisms of modulating the electromagnetic oscillation frequency of the defect unit through a shunting circuit are analyzed. Finally, the defect unit with tunable electromagnetic oscillation frequency is incorporated into the perfect Phononic Crystals to create a point defect. It is verified that adjusting the circuit parameters of the external shunting circuit to modulate the defect frequency of the Phononic Crystals with defect unit and to apply it for filtering within the bandgap range is effective. The work presented in this paper provides an important reference for addressing low-frequency vibration control issues in the automotive industry.

Enhanced Vision-Based Quality Inspection: A Multiview Artificial Intelligence Framework for Defect Detection

Automated defect detection is a critical component of modern industrial quality control. However, it is particularly difficult to identify subtle defects such as scratches on metallic surfaces. Therefore, this paper investigates the effectiveness of multiview deep learning approaches for improved defect detection by implementing and comparing early and late fusion methodologies. We propose MV-UNet, a novel early fusion architecture that aligns and aggregates multiview features using a transformation block to enhance detection accuracy. To evaluate performance, we conduct our experiments on a recorded metallic plates dataset, comparing the traditional single-view inspection to both late and early fusion methods. Our results demonstrate that both the early and late fusion methods improve detection accuracy over the mono-view baseline, with our MV-UNet achieving the hightest F1-score (0.942). Additionally, we introduce adapted precision–recall metrics designed for segmentation-based defect detection, addressing the limitations of traditional IoU-based evaluations. These tailored metrics more accurately reflect defect localization performance, particularly for thin, elongated scratches. Our findings highlight the advantages of early fusion for industrial defect detection, providing a robust and scalable approach to multiview analysis.

Minced cartilage for focal cartilage defects-A comprehensive systematic review of surgical techniques in clinical studies, animal studies and basic research studies.

This study aimed to determine whether the minced cartilage procedure for treating focal cartilage defects is already a standardized technique. A systematic literature review was conducted in MEDLINE (PubMed), EMBASE and Google Scholar to include all relevant studies (clinical studies, animal studies and basic research) investigating minced cartilage for treating focal cartilage defects. A total of 8 clinical studies, 14 animal studies and 17 basic research studies met the inclusion criteria. Among the eight clinical studies, one was a randomized controlled trial (minced cartilage vs. microfracture), one was a matched-cohort study (minced cartilage vs. autologous matrix-induced chondrogenesis), while the other six studies were case series with a small number of patients (maximum 28). Defect localization varied among the studies: most frequently femoral condyle defects were treated, followed by trochlea/patella. In three studies, cartilage was harvested and minced with a scalpel; in two studies, cartilage was harvested and minced with a shaver. The other clinical studies used a mixture of a curette, a scalpel or a shaver. Six studies used fibrin glue to seal the implanted cartilage. In three studies, a matrix was used for defect coverage. In two studies, cartilage was additionally augmented with autologous blood products. All animal and basic research studies observed similar differences regarding each surgical step. A standardized minced cartilage procedure has not yet emerged. There are differences in the methods of cartilage mincing, cartilage fixation, cartilage coverage using matrices and augmentation with autologous blood products. Level III.

Atomic Symbiotic‐Catalyst for Low‐Temperature Zinc‐Air Battery

AbstractAtomic‐level designed electrocatalysts, including single‐/dual‐atom catalysts, have attracted extensive interests due to their maximized atom utilization efficiency and increased activity. Herein, a new electrocatalyst system termed as “atomic symbiotic‐catalyst”, that marries the advantages of typical single‐/dual‐atom catalysts while addressing their respective weaknesses, was proposed. In atomic symbiotic‐catalyst, single‐atom MNx and local carbon defects formed under a specific thermodynamic condition, act synergistically to achieve high electrocatalytic activity and battery efficiency. This symbiotic‐catalyst shows greater structural precision and preparation accessibility than those of dual‐atom catalysts owing to its reduced complexity in chemical space. Meanwhile, it outperforms the intrinsic activities of conventional single‐atom catalysts due to multi‐active‐sites synergistic effect. As a proof‐of‐concept study, an atomic symbiotic‐catalyst comprising single‐atom MnN4 moieties and abundant sp3‐hybridized carbon defects was constructed for low‐temperature zinc‐air battery, which exhibited a high peak power density of 76 mW cm−2 with long‐term stability at −40 °C, representing a top‐level performance of such batteries.

Intrinsic Defect-Induced Local Semiconducting-to-Metallic Regions Within Monolayer 1T-TiS2 Displayed by First-Principles Calculations and Scanning Tunneling Microscopy

Using density functional theory (DFT) and scanning tunneling microscopy (STM), the intrinsic point defects, formation energy, and electronic structure of 1T-TiS2 were investigated. Defect systems include single-atom vacancies, interstitial and adatom additions, and direct atomic substitution. Using a collective approach for analyzing realistic systems for point defect investigation, we provide a more straightforward comparison to the experimental measurements, reproducing more realistic environmental conditions related to thin film growth. STM images are compared to computationally simulated electron density images to identify specific geometries that result from favorable point defects. DFT suggests that titanium interstitials are the most energetically favorable intrinsic defect, and sulfur vacancies are more likely to form than titanium vacancies within this realistic analysis, which is in agreement with STM data. A pristine, stoichiometric monolayer system is calculated to have a direct band gap of 0.422 eV, which varies based on local point defects. Local semiconducting-to-metallic electronic transitions are predicted to occur based on the presence of Ti interstitials.

In the Era of Advanced Microsurgery, Is There Still a Place for Pedicled Abdominal Flaps? A Retrospective Analysis

Background: Upper extremity reconstruction poses a significant challenge due to the complex anatomical and functional requirements of the hand and forearm. While free flaps have become the gold standard, pedicled abdominal flaps remain a valuable alternative, especially in cases where microsurgical anastomosis is contraindicated or unfeasible. This study evaluates the efficacy and outcomes of free-style pedicled abdominal flaps in reconstructing complex upper limb defects. Methods: A retrospective review was conducted on 20 patients who underwent soft tissue reconstruction of the upper extremity using free-style pedicled abdominal flaps between January 2019 and June 2024. Patient demographics, injury mechanisms, flap design, postoperative complications, and clinical outcomes were analyzed. Flap design was customized to defect size and location, utilizing single, double, triple, and tunneled flap configurations where necessary. Results: Stable soft tissue coverage was achieved in all cases without the need for additional free flap procedures. Complications included surgical site infections (n = 2), marginal necrosis (n = 2), partial flap necrosis (n = 2), and complete necrosis (n = 2), with no cases requiring free flap conversion. Long-term follow-up revealed no finger stiffness or loss of hand function. Donor site morbidity was minimal, with only one case requiring a split-thickness skin graft for closure. Conclusions: Despite advancements in microsurgical techniques, free-style pedicled abdominal flaps remain a vital reconstructive option for upper limb defects, particularly in patients with complex, large, or circumferential injuries. Their versatility, reliable vascularity, and ability to conform to various defect shapes underscore their enduring relevance in modern reconstructive surgery.

Anthrone/XLPE: an adaptive charge capture intelligent insulation material for advanced electric power transmission

The degradation of electrical insulation is mainly attributed to local defects. Although incorporating organic small molecules into dielectric polymers promotes the insulation strength, accurate suppression of defect development is a long-term and formidable challenge. Here we utilize the adaptive charge capture methodology to achieve precise defect suppression, leading to a 123% increase in the initiation voltage of electrical trees in anthrone/cross-linked polyethylene, significantly outperforming existing dielectric polymers and polymer composites. A significant observation is the confinement of charge at the interface between the anode and cross-linked polyethylene in anthrone/cross-linked polyethylene, generating a reverse inherent electric field near the interface and reducing the internal electric field strength of cross-linked polyethylene by up to 18%. These findings not only open avenues for further exploration of materials for ultra-high voltage cables but also play a crucial role in the commercialization and practical application of organic semiconductors in insulation dielectrics.

Defect detection and localization in hydrogen pipelinesusing acoustic emission technique

The structural integrity of hydrogen pipelines is critical for ensuring the safe and efficient transportation of hydrogen as a clean energy carrier. Over time, potential defects such as hydrogen embrittlement-induced cracks, weld defects, and leakages may occur along pipelines stretched across long distances. To monitor the health of such infrastructures in real-time, acoustic emission (AE) monitoring has emerged as a promising non-destructive evaluation (NDE) and passive method. This study investigates the application of AE technique to detect and localize controlled defects along metal pipelines. Experiments were conducted on a steel pipe specimen mounted with AE sensors laid out in a triangulation array, and a controlled AE source. The AE signals generated by the source were analysed to identify characteristic parameters, such as amplitude, frequency, rise time, counts, and signal duration for early defect detection. With the sensors laid out in an array configuration, the AE sources can also be accurately localised along the pipe walls. Results demonstrate that AE can effectively in-situ monitor and localise defects in pipeline, providing valuable insights into the infrastructure integrity. Furthermore, triangulation algorithms were employed to improve defect classification and localization accuracy. With the accurate localisation of an AE sensor array, non-destructive testing (NDT) methods can be supplemented for a more thorough inspection and characterisation of the localised defect. This work highlights AE testing as a viable, real-time monitoring tool for enhancing the safety and reliability of hydrogen pipeline infrastructure.

Reconstruction of Posterior Trunk Defects Following Sarcoma Excisions-A Dual-Center Experience.

Sarcomas are malignancies of mesodermal origin that have a propensity for aggressive invasion of local structures and hematogenous spread. Sarcomas of the posterior trunk are problematic because of their insidious growth, lack of patient realization, and proximity to the vertebral column and spinal cord. Reconstruction often requires well-vascularized tissue that can withstand the demands of radiotherapy, without significant complications. We assessed the outcomes of 47 patients over a 7-year period with soft-tissue sarcomas of the posterior trunk extending from the neck to the sacrum and their reconstructions. Nine were direct closures, and 2 required split-thickness skin grafts. Thirty-seven patients underwent 39 flap reconstructions (26 myocutaneous, 12 fasciocutaneous, 1 muscle-only). Thirty-five patients required a single flap reconstruction, and 2 required multiple flaps. There were no recorded flap failures. Thirty-three patients (70%) healed without complications. Twenty-one patients required radiotherapy (preoperative 3, postoperative 18) and wound healing complications occurred in one (33%) and 5 (27%%) patients, respectively. Complications: seroma (10%), dehiscence (12.8%), return to theater (12.8%), infection (12.8%), and partial flap necrosis (10%). No statistical significance was found when comparing sex, smoking status, diabetes, defect location, or radiotherapy exposure with wound complication outcomes. There was no statistical significance when comparing wound complications, return to theater or healing time between those who had received preoperative and postoperative radiotherapy. Patients with posterior trunk sarcomas often require well-vascularized robust reconstruction that can withstand the potential complications of radiotherapy and pressure. Reconstruction can include fasciocutaneous or musculocutaneous flaps, or a combination of both, to help reduce morbidity.

Advancements in AI-Driven detection and localisation of solar panel defects

Advancements in AI-Driven detection and localisation of solar panel defects

A study on the role of local residual stress on the local strength and defect growth in laser-welded Ti-6Al-4V

A study on the role of local residual stress on the local strength and defect growth in laser-welded Ti-6Al-4V

Simulated effect of defect volume and location on very high cycle fatigue of laser beam powder bed fused AlSi10Mg

Simulated effect of defect volume and location on very high cycle fatigue of laser beam powder bed fused AlSi10Mg

Enhancing Guided Wave Tomography for Improved DefectDetection in Critical Structures

Containment liner plates are essential for structural safety in critical systems. Detecting defects in these components requires advanced non-destructive testing (NDT) techniques to address challenges such as complex geometries and material properties. Tomographic imaging reconstructs damage probability maps by analyzing guided wave interactions, offering detailed visualizations of defect locations and enabling precise localization in challenging scenarios. This study evaluates two tomographic methodologies: the Reconstruction Algorithm for Probabilistic Inspection of Defects (RAPID) and the enhanced Density Clustering-RAPID (DC-RAPID). RAPID provides a robust framework for defect localization by leveraging optimized shape factors to enhance sensitivity and probability mapping. However, it struggles with achieving precise localization in complex geometries or under noisy conditions. DC-RAPID overcomes these limitations by integrating density-based clustering, which effectively reduces false positives and identifies high-probability zones. Incorporating adaptive probability mapping, DC-RAPID significantly enhances imaging quality and defect resolution. Comparative analysis demonstrates the superior accuracy and reliability of DC-RAPID in identifying and characterizing defects. These advancements highlight the potential of guided wave tomography, particularly DC-RAPID, for improving NDT in critical structures.

Effects of defect locations and loading voltages on breakdown of GIL tri-post insulators

Effects of defect locations and loading voltages on breakdown of GIL tri-post insulators

FDEM numerical simulation of size effect on mechanical properties of basalts with hidden microcracks

As an important geological environment medium for engineering construction in southwest China, basalt generally contains hidden microcracks at a micro-scale, which leads to significant size effect on its mechanical properties, and relevant research is lacking and unsystematic. A synthetic rock mass model based on the combination of a micro-discrete fracture network method and a finite-discrete element method is used to systematically explore the size effect of the mechanical properties of basalt rock blocks with hidden microcracks. The results showed that: (1) the fracture angle is uniformly distributed, and the fracture length conforms to the logarithmic normal distribution, with an areal fracture intensity P20 of 0.00025/mm2 and P21 of 0.012 mm/mm2. (2) According to the variation trends of mechanical parameters with the increase in the specimen dimension, the REV size of basalt rock blocks with hidden microcracks is determined to be 0.5 m. The mechanical properties obtained at this size are considered equivalent continuum properties and could be used as input parameters of rock blocks in complete rock mass or jointed rock mass for the numerical analysis at an engineering scale. (3) With the increase in the sample dimension, basalt changes from a small-sized complete sample to a medium-sized sample with local defects and then to an REV-sized sample with sufficient defects, the stress–strain curve characteristics under Brazilian disc splitting change from a single-peak shape to a zigzag shape and then to a multi-peak shape, and the failure modes changes from a single-center splitting failure mode to a local structure-controlled failure mode and then to a multi-center splitting failure mode, with the gradual decrease in the brittleness degree. The research results further enrich and improve the basic theory and technical methods of multi-scale analysis of geotechnical engineering, and provide strong scientific and technological support for the safety construction of deep engineering.

A Novel Hydrogen Leak Detection Method for PEM Fuel Cells Using Active Thermography

Hydrogen leakage in Proton Exchange Membrane (PEM) fuel cells poses critical safety, efficiency, and operational reliability risks. This study introduces an innovative infrared (IR) thermography-based methodology for detecting and quantifying hydrogen leaks towards the outside of PEM fuel cells. The proposed method leverages the catalytic properties of a membrane electrode assembly (MEA) as an active thermal tracer, facilitating real-time visualisation and assessment of hydrogen leaks. Experimental tests were conducted on a single-cell PEM fuel cell equipped with intact and defective gaskets to evaluate the method’s effectiveness. Results indicate that the active tracer generates distinct thermal signatures proportional to the leakage rate, overcoming the limitations of hydrogen’s low IR emissivity. Comparative analysis with passive tracers and baseline configurations highlights the active tracer-based approach’s superior positional accuracy and sensitivity. Additionally, the method aligns detected thermal anomalies with defect locations, validated through pressure distribution maps. This novel, non-invasive technique offers precise, reliable, and scalable solutions for hydrogen leak detection, making it suitable for dynamic operational environments and industrial applications. The findings significantly advance hydrogen’s safety diagnostics, supporting the broader adoption of hydrogen-based energy systems.

LithoExp: Explainable Two-stage CNN-based Lithographic Hotspot Detection with Layout Defect Localization

LithoExp: Explainable Two-stage CNN-based Lithographic Hotspot Detection with Layout Defect Localization

Electron-Phonon Coupling and Phonon Dynamics in Single-Layer NbSe2 on Graphene: The Role of Moiré Phonons.

The interplay between substrate interactions and electron-phonon coupling in two-dimensional (2D) materials presents a significant challenge in understanding and controlling their electronic properties. Here, we present a comparative study of the structural characteristics, phonon dynamics, and electron-phonon interactions in bulk and monolayer NbSe2 on epitaxial bilayer graphene (BLG) using helium atom scattering (HAS). High-resolution helium diffraction reveals a (9 × 9)0° superstructure within the NbSe2 monolayer, commensurate with the BLG lattice, while out-of-plane HAS diffraction spectra indicate a low-corrugated (3√3 × 3√3)30° substructure. By monitoring the thermal attenuation of the specular peak across a temperature range of 100 to 300 K, we determined the electron-phonon coupling constant (λHAS) as 0.76 for bulk 2H-NbSe2. In contrast, the NbSe2 monolayer on graphene exhibits a reduced λHAS of 0.55, corresponding to a superconducting critical temperature (TC) of 1.56 K according to the MacMillan formula, consistent with transport measurement findings. Inelastic HAS data provide, besides a set of dispersion curves of acoustic and lower optical phonons, a soft, dispersionless branch of phonons at 1.7 meV, attributed to the interface localized defects distributed with the superstructure period, thus termed Moiré phonons. Our data show that Moiré phonons contribute significantly to the electron-phonon coupling in monolayer NbSe2. These results highlight the crucial role of the BLG in the electron-phonon coupling in monolayer NbSe2, attributed to enhanced charge transfer effects, providing valuable insights into substrate-dependent electronic interactions in 2D superconductors.