Search Results (127)

The global rise in obesity presents significant challenges for reconstructive surgery. Effective postoperative monitoring of tissue flap vitality is essential for successful outcomes, but obesity introduces complexities that can hinder accurate assessments. This article examines the specific challenges associated with monitoring tissue flap viability in individuals with obesity, focusing on how obesity-related physiological changes affect the effectiveness of various monitoring techniques. We explore alterations in subcutaneous adipose tissue—such as thickness, density, and volume—as well as changes in vessel structure, blood pressure, glucose levels, lactate levels, and tissue perfusion. These factors can impact the accuracy and reliability of monitoring methods. A deep understanding of these challenges is crucial for determining the suitability of different monitoring systems for patients with obesity undergoing flap reconstruction. Based on a review of clinical experience, we assess the usability of widely used monitoring devices, including ultrasound Doppler, near-infrared spectroscopy, and laser Doppler flowmetry, in patients with obesity. Non-conventional techniques such as glucose and lactate measurements, thermography, and fluorescence angiography are also investigated. This article aims to provide a comprehensive overview of the relationship between obesity and tissue flap monitoring, ultimately helping to select the most appropriate and effective methods for this patient population. By considering these factors, surgeons in cooperation with engineers can optimize postoperative care and enhance the likelihood of successful flap reconstruction. Full article

Infrared thermography non-destructive testing technology has been widely used in the defect detection of composite structures due to its advantages, including non-contact operation, rapidity, low cost, and high precision. In this study, a laser-line scanning system combined with an infrared thermography was developed, along with a corresponding dynamic sequence image reconstruction method, enabling rapid localization of surface damages. Then, high-precision quantitative characterization of defect morphology in reconstructed images was achieved by integrating an edge gradient detection algorithm. The reconstruction method was validated through finite element simulations and experimental studies. The results demonstrated that the laser-line scanning thermography effectively enables both rapid localization of surface damages and precise quantitative characterization of their morphology. Experimental measurements of ceramic materials indicate that the relative error in detecting crack width is about 6% when the crack is perpendicular to the scanning direction, and the relative error gradually increases when the angle between the crack and the scanning direction decreases. Additionally, an alumina ceramic plate with micrometer-width cracks is inspected by the continuous laser-line scanning thermography. The morphology detection results are completely consistent with the actual morphology. However, limited by the spatial resolution of the thermal imager in the experiment, the quantitative identification of the crack width cannot be carried out. Finally, the proposed method is also effective for detecting surface damage of wrinkles in ceramic matrix composites. It can localize damage and quantify its geometric features with an average relative error of less than 3%, providing a new approach for health monitoring of large-scale ceramic matrix composite structures. Full article

Infrared thermography, particularly its active form, is increasingly used in various industries in non-destructive testing (NDT). To support its broader adoption, structured standardization efforts have been developed within CEN/TC 138/WG11 and coordinated with ISO. Key standards—such as EN 16714, EN 17119, and EN 17501—define principles, procedures, and equipment requirements. Current activities include finalizing the draft on induction thermography, revising EN 17119, and developing new projects on optical lock-in, laser weld inspection, and thermal diffusivity. Standardization enhances comparability, reliability, and certification, making thermography a robust and scalable solution within the global NDT framework. Full article

Classical active thermographic testing of industrial goods has mostly been limited to generating 2D defect maps. While for surface or near-surface defect detection, this is a desired result, for deeply buried defects, a 3D reconstruction of the defect geometry is coveted. This general trend can also be well observed in widely used NDT methods (radiography, ultrasonic testing), where the progression from 2D to 3D reconstruction methods has already made profound progress (CT, UT phased array transducers). Achieving a fully 3D defect reconstruction in active thermographic testing suffers from the diffusive nature of thermal processes. One possible solution to deal with thermal diffusion is the application of the virtual-wave concept, which, by solving an inverse problem, allows the diffusiveness to be extracted from the thermographic data in the post-processing stage. What is left follows propagating-wave physics, enabling the usage of well-known algorithms from ultrasonic testing. In this work, we present our progress in the 3D reconstruction of deeply buried defects using spatially structured laser heating in conjunction with applying the well-known total focusing method (TFM) in the virtual-wave domain. Full article

This work presents a non-destructive methodology to estimate the residual porosity and mechanical properties of titanium foams produced via Hot Isostatic Pressing (HIP) followed by solid-state foaming (SSF). Pulsed laser-spot thermography was employed to measure thermal diffusivity in compact and foamed Ti6Al4V-ELI samples derived from powders of different granulometries. A power-law correlation between thermal diffusivity and porosity was used to estimate post-foaming porosity, which was then used to predict elastic modulus, yield strength, and ultimate tensile strength. Results highlight the potential of thermal diffusivity as a reliable indicator of structural performance, offering a rapid and fully non-destructive route for evaluating metallic foams in biomedical and aerospace applications. Full article

Traditional infrared thermography (IRT) techniques can only provide two-dimensional (2D) projections of surface temperatures, and it is difficult to intuitively present the surface profile of the three-dimensional (3D) structure and the spatial distribution of the internal defects. In this paper, a low-cost, high efficiency and high precision photothermal 3D tomography technology was proposed by combing 3D thermography and infrared tomography for the first time. Specifically, this paper abandoned additional 3D sensors and complex motion systems such as robotic arms and scanning platforms. Differently, it utilized a galvanometer to deflect laser for line structure light scanning, and captured the thermal stripes generated on the structural surface using an infrared camera, and then realized the highly efficient 3D reconstruction; moreover, this work introduced undersampling strategy into photothermal coherence tomography (PCT) technology to enhance the ranging depth, and the ranging results were transmitted to the 3D coordinate system, so as to realize the photothermal 3D tomography. Through the detection experiments of metal additive manufacturing parts, it was shown that the proposed method could reconstruct the 3D contour of the specimen, and identified the first heterogeneous interface below the surface of the specimen. Full article

In additive manufacturing (AM), particularly with AlSi10Mg aluminum alloy produced via Laser Powder Bed Fusion (L-PBF), understanding and detecting defects is crucial for ensuring mechanical integrity. This study evaluates the effectiveness of active thermography as a fast, non-destructive testing (NDT) method for identifying typical L-PBF defects. Artificial defects (cubes, spheres, cylinders with unfused powder) were introduced by varying printing parameters. Their real geometry was assessed via micro-computed tomography (μ-CT), revealing deviations from nominal shapes. Thermographic tests using a laser heat source (≈40 W/cm²) were conducted to examine the detectability of these defects in the highly diffusive material AlSi10Mg. Results highlight both the limitations and potential of thermography as a cost- and time-effective alternative to μ-CT for quantitative inspection. Full article

An infrared thermographic technique was developed for identifying the thermal diffusivity from temperature variation data of the specimen surface. Laser-spot heating is applied to the specimen surface for a certain period, and then, temperature variation in the surface is measured using infrared thermography. Since analytical solution for the temperature variation is expressed in terms of parameters including the thermal diffusivity, thickness and heating point position, the parameters are identified by fitting the analytical solution to the measured data. The developed technique was applied to a ceramic specimen for verification. It was shown that the thermal diffusivity can be identified with high accuracy if the thickness and heating point position are known in advance. Furthermore, it is confirmed that the thermal diffusivity, thickness, and heating point position can be simultaneously estimated with acceptable accuracy. Full article

Historic masonry churches are highly vulnerable to structural degradation and seismic hazards due to their geometric complexity, material ageing, and lack of detailed construction records. The Church of Santos Juanes in Valencia, a monument of exceptional historical and architectural value, presents these challenges, intensified by centuries of transformations and partial loss of documentation. In this study, we develop a comprehensive methodology that integrates historical research, non-destructive testing (3D laser scanning with Leica Geosystems Cyclone v9.1.1; infrared thermography, commercial software; ground-penetrating radar with gprMax 2016 and GPR-SLICE v7.MT), and advanced finite element modelling (Angle v1). The integrated survey data enabled the creation of an accurate 3D geometric model, the detection of hidden construction elements, and the characterisation of subsoil stratigraphy. Structural simulations under static and seismic loading—considering soil–structure interaction—revealed the high global stiffness of the complex, the influence of the Baroque vault on load distribution, and localised vulnerabilities, particularly in the San Juan ‘O’ façade, which coincide with existing cracks confirmed by thermography. This methodological framework not only advances the diagnosis and conservation of Santos Juanes but also provides a replicable model for assessing and safeguarding other heritage buildings with similar typological and structural challenges. Full article

This paper reviews recent advances in machine learning (ML) algorithms to improve the postprocessing and interpretation of thermographic data in non-destructive testing (NDT). While traditional NDT methods (e.g., visual inspection, ultrasonic testing) each have their own advantages and limitations, thermographic techniques (e.g., pulsed thermography, laser thermography) have become valuable complementary tools, particularly in inspecting advanced materials such as carbon fiber-reinforced polymers (CFRPs) and superalloys. These techniques generate large volumes of thermal data, which can be challenging to analyze efficiently and accurately. This review focuses on how ML can accelerate defect detection and automated classification in thermographic NDT. We summarize currently popular algorithms and analyze the limitations of existing workflows. Furthermore, this structured analysis provides an in-depth understanding of how artificial intelligence can assist in processing NDT data, with the potential to enable more accurate defect detection and characterization in industrial applications. Full article

Climate concerns are driving the automotive industry to adopt advanced manufacturing technologies that aim to improve energy efficiency and reduce vehicle weight. In this context, lightweight structural materials such as aluminium alloys have gained significant attention due to their favorable strength-to-weight ratio. Laser welding plays a crucial role in assembling such materials, offering high flexibility and fast joining capabilities for thin aluminium sheets. However, welding these materials presents specific challenges, particularly in controlling heat input to minimize distortions and ensure consistent weld quality. As a result, numerical simulations based on the Finite Element Method (FEM) are essential for predicting weld-induced phenomena and optimizing process performance. This study investigates welding-induced distortions in laser butt welding of 1.5 mm-thick Al 6061 samples through FEM simulations performed in the SYSWELD 2024.0 environment. The methodology provided by the software is based on the Moving Heat Source (MHS) model, which simulates the physical movement of the heat source and typically requires extensive calibration through destructive metallographic testing. This transient approach enables the detailed prediction of thermal, metallurgical, and mechanical behavior, but it is computationally demanding. To improve efficiency, the Imposed Thermal Cycle (ITC) model is often used. In this technique, a thermal cycle, extracted from an MHS simulation or experimental data, is imposed on predefined subregions of the model, allowing only mechanical behavior to be simulated while reducing computation time. To avoid MHS-based calibration, this work proposes using thermal cycles acquired in-line during welding via infrared thermography as direct input for the ITC model. The method was validated experimentally and numerically, showing good agreement in the prediction of distortions and a significant reduction in workflow time. The distortion values from simulations differ from the real experiment by less than 0.3%. Our method exhibits a slight decrease in performance, resulting in an increase in estimation error of 0.03% compared to classic approaches, but more than 85% saving in computation time. The integration of real process data into the simulation enables a virtual representation of the process, supporting future developments toward Digital Twin applications. Full article

The aim of the present study was to assess the thermal effects of high-intensity laser therapy (HILT) on the temporomandibular joint (TMJ) area of clinically healthy Thoroughbred racehorses. The study was conducted on 21 clinically healthy Thoroughbreds in regular training. The horses were subjected to thermographic examinations before and immediately after a HILT session to measure changes in the body surface temperature in the TMJ area. The left TMJ was subjected to therapy, while the contralateral joint served as a control. Statistically significant differences in the body surface temperature in the TMJ area—before and after HILT—were found (p < 0.001). The body surface temperature of the area examined was higher by an average of 2.0 °C after HILT, compared to the temperature measured before HILT. The results prove the thermal effect of HILT in the TMJ area, which can be helpful in determining the appropriate and safe HILT parameters for the treatment of TMJ injuries and inflammation. Full article

Background/Objectives: This study evaluated the effects of vascular photobiomodulation (VPBM) on pain intensity, edema, and facial temperature variation in patients undergoing alveolar bone grafting (ABG) surgery. Methods: A total of 42 patients with cleft lip and palate (aged 9–25 years) scheduled for ABG using iliac crest bone were randomly assigned in equal numbers (14 per group) to one of three groups: control (ABG only), test (ABG + VPBM), and placebo (ABG + simulated VPBM). Iliac and facial pain and edema were clinically evaluated 24 h post-surgery, along with thermographic facial analysis. Follow-up was conducted via phone calls for one week. Results: No statistically significant differences were observed among the groups regarding facial pain and edema at 24 h post-surgery. However, iliac pain significantly differed between the placebo and control groups (p = 0.045). A significant time-related effect on both facial and iliac pain outcomes was noted during follow-up, irrespective of the group. The need for rescue medication and self-perception of reduced edema did not differ significantly. Thermographic analysis reveals a significantly lower temperature variation in the test group (2.36 °C) compared to the other groups (p = 0.007). Conclusions: Overall, VPBM therapy influenced postoperative pain in the early recovery phase and temperature in the immediate postoperative period but did not significantly affect edema. Full article

Additive manufacturing (AM) has revolutionized production across industries, yet persistent challenges in defect detection and process reliability necessitate advanced in situ monitoring solutions. While non-destructive evaluation (NDE) techniques such as X-ray computed tomography, thermography, and ultrasonic testing have been widely adopted, the critical role of 3D surface topographic monitoring remains underutilized for real-time anomaly detection. This work comprehensively reviews the 3D surface monitoring of AM processes, such as Laser powder bed fusion, directed energy deposition, material extrusion, and material jetting, highlighting the current state and challenges. Furthermore, the article discusses the state-of-the-art advancements in closed-loop feedback control systems, sensor fusion, and machine learning algorithms to integrate 3D surface data with various process signatures to dynamically adjust laser parameters and scan strategies. Guidance has been provided on the best 3D monitoring technique for each of the AM processes. Motivated by manufacturing labor shortages, the high skill required to operate and troubleshoot some of these additive manufacturing techniques, and zero-defect manufacturing goals, this paper also explores the metamorphosis towards autonomous AM systems and adaptive process optimization and explores the role and importance of real-time 3D monitoring in that transition. Full article

In this paper, the characterization of the deformation behavior of additively manufactured 3D-printed Ti-6Al-4V alloys during elastic and plastic deformation was carried out on the test samples deformation zone during cold deformation at room temperature. The additive manufacturing process direct metal laser sintering (DMLS) was used to 3D print the Ti-6Al-4V test samples. The temperature, i.e., stress, changes, strain, and strain rate distribution in the deformation zone of the 3D-printed Ti-6Al-4V alloy during elastic and plastic deformation were compared using static tensile tests, thermography, and digital image correlation (DIC) simultaneously. Periodic oscillations of the maximum temperature changes during elastic and plastic deformation were observed in the deformation zone. The thermoelastic effect with the lowest temperature drop between −0.47 °C and −0.54 °C was observed in the deformation zone of the 3D-printed Ti-6Al-4V testing samples during elastic deformation. A significant difference between strain and strain rate localization in the deformation zone was found immediately before fracture of the test sample. Maximum strain amounts in the range of 0.078–0.080 and strain rates of 0.025–0.027 s⁻¹ were determined. Static tensile tests, thermography, and digital image correlation were proved to be valid methods for determining the localization of stress, strain, and strain rate in the deformation zone of 3D-printed Ti-6Al-4V test samples. Full article