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Application of infrared thermography in diagnosing peripherally inserted central venous catheter infections in children with cancer
摘要： Children affected by oncological diseases are often fitted with central venous catheters. Catheter infection is a frequent complication, sometimes accompanied by thrombosis. It is designed a case/control-type pilot study of children with oncological diseases fitted with a central venous catheter. The objective of this preliminary study is to use infrared thermography to discern whether there is an infection in patients with a central venous catheter and if so, to undertake a close follow-up of its evolution, after administering a therapy. It is measured Thermal Asymmetry by mean and maximum temperatures (Temperature affected ROI – Temperature contralateral ROI). In all cases with catheter infection, Thermal Asymmetry values were higher than in controls without infection, allowing us to assess improvement after starting the treatment. These preliminary results are satisfactory because they reflect the advantages of using infrared thermography on oncological child patients, as it is a harmless, non-contact, accessible and quick technique, allowing us to reduce the use of ionizing radiation and quantify the clinical signs of inflammation, which are otherwise only qualitatively detectable in the clinical examination. By doing so, it may be possible to anticipate infection and provide early treatment, and, moreover, to observe whether there is any complication after starting a treatment. More studies need to be undertaken with an extensive paediatric population to establish reference values.
关键词： infrared thermography,central venous catheter infection,cancer,children
更新于2025-09-19 17:15:36
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Can UAV-Based Infrared Thermography Be Used to Study Plant-Parasite Interactions between Mistletoe and Eucalypt Trees?
摘要： Some of the remnants of the Cumberland Plain woodland, an endangered dry sclerophyllous forest type of New South Wales, Australia, host large populations of mistletoe. In this study, the extent of mistletoe infection was investigated based on a forest inventory. We found that the mistletoe infection rate was relatively high, with 69% of the Eucalyptus fibrosa and 75% of the E. moluccana trees being infected. Next, to study the potential consequences of the infection for the trees, canopy temperatures of mistletoe plants and of infected and uninfected trees were analyzed using thermal imagery acquired during 10 flights with an unmanned aerial vehicle (UAV) in two consecutive summer seasons. Throughout all flight campaigns, mistletoe canopy temperature was 0.3–2 K lower than the temperature of the eucalypt canopy it was growing in, suggesting higher transpiration rates. Differences in canopy temperature between infected eucalypt foliage and mistletoe were particularly large when incoming radiation peaked. In these conditions, eucalypt foliage from infected trees also had significantly higher canopy temperatures (and likely lower transpiration rates) compared to that of uninfected trees of the same species. The study demonstrates the potential of using UAV-based infrared thermography for studying plant-water relations of mistletoe and its hosts.
关键词： plant hemiparasite,transpiration,infrared thermography,UAV
更新于2025-09-19 17:15:36
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Study of infrared thermal application for detecting defects within tunnel lining
摘要： With the aging of tunnels, additional maintenance and assessment procedures are required to monitor their working conditions. The passive thermal infrared method, which is a nondestructive contact-free method, is used to find defects in a box-type and shield tunnels with concrete lining. In this study, this method is numerically applied to detect defects in an unhealthy concrete structure. The thermal field data measurements are reviewed and the governing heat transfer mechanisms for a defected concrete surface are presented. The heat transfer in the concrete segment, tunnel air, and the air inside the void due to the conduction, convection, and radiation mechanisms is explained. Further, the type of cavity, the temperature difference between the healthy and unhealthy concrete surfaces, the temperature difference between the tunnel air and concrete surfaces, and the influence of the void depth on the detection accuracy are investigated. The results show that the temperature difference between the concrete surface and the tunnel air is more than 0.35 °C, which is an ideal condition for detecting the voids with an approximate depth of 30 mm or less.
关键词： Hammering test,Heat transfer,Infrared thermography,Defected lining,RC tunnel lining
更新于2025-09-19 17:15:36
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Measuring the in-plane thermal diffusivity of moving samples using laser spot lock-in thermography
摘要： In this work we deal with samples that move at constant speed and are illuminated by a modulated and focused laser beam. We have obtained a general expression for the surface temperature of these moving samples: it is valid not only for opaque and thermally thick materials, but also for thermally thin and semitransparent samples. Moreover, heat losses by convection and radiation are taken into account in the model. Numerical calculations indicate that the temperature (amplitude and phase) profiles in the directions parallel and perpendicular to the sample motion are straight lines with respect to the distance to the laser spot. The slopes of these straight lines depend on sample speed, modulation frequency and in-plane thermal diffusivity of the sample. Provided the two first experimental parameters are known, the in-plane thermal diffusivity can be retrieved in a simple manner. Measurements performed on materials covering a wide range of thermal diffusivity values, from insulators to good thermal conductors, confirm the validity of these linear methods.
关键词： Infrared thermography,Lock-in thermography,Photothermal techniques,Thermal diffusivity
更新于2025-09-19 17:13:59
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Aerial Infrared Thermography: A Scalable Procedure for Photovoltaics Inspections Based on Efficiency and Flexibility
摘要： The objective of this contribution is to explore innovative ways to increase the efficiency of large scale photovoltaic systems (LSPVS) in the medium term through effective management of operating, monitoring and maintenance (OMM) costs based on aerial surveillance with small multi-rotor flight robot (s-MRFR). An effective solution of OMM cost assessment must capture the dynamic interaction between energy market developments, technological progress and investor tolerance to the risk posed by climate changes. The valuation method for OMM cost-risk analysis is based on generalized Wiener process with stochastic jumps. The interest is to increase the value of the investment by using innovative but efficient procedures of PV systems inspection based on aerial infrared thermography. The results are encouraging because the total costs of s-MRFR monitoring are very low compared to the benefits.
关键词： Photovoltaic systems,small multi-rotor flight robot,aerial infrared thermography,climate change impacts,cost analysis
更新于2025-09-16 10:30:52
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AIP Conference Proceedings [AIP Publishing PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019 - Tomsk, Russia (1–5 October 2019)] PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019 - Infrared thermography inspection of severe friction on UFG stainless steel, copper and aluminum alloy
摘要： Friction-generated heat is an important factor that determines the stability of sliding friction conditions and thus has to be taken into account especially when using ultrafine-grained materials for tribological applications. Thermal stability of these materials under friction sliding conditions must be studied and the first approach here is to determine the temperature distributions below the worn surfaces. For this purpose, we used an IR thermal imaging camera attached to a tribological setup and three materials with different heat conductivity values: AISI 321 stainless steel, 5052 aluminum alloy and C11000 copper as specimens. The results show that even if the measured temperatures were below the standard recrystallization start temperatures, the recrystallization still was feasible due to severe friction-induced subsurface deformation.
关键词： Infrared thermography,sliding friction,recrystallization,thermal stability,UFG materials
更新于2025-09-16 10:30:52
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Comparison between multi-frequency and multi-speed laser lock-in thermography methods for the evaluation of crack depths in metal
摘要： Two original methods using lock-in thermography with a laser excitation are proposed for the estimation without contact of open crack depths in metal. The first uses a modulated punctual thermal source and is well suited for the study of complicated structures. In the second, a continuous moving thermal source allows to scan homogeneous structures. Each method relies on the heat diffusion modifications induced by a crack located in the thermal diffusion area of the synchronised heat source. The thermal signature of the crack is extracted to the amplitude of surface temperature images for various modulation frequencies or various scanning speeds of the thermal source. The thermal signatures are analysed according to a length representative of the thermal diffusion length to give a local evaluation of the crack depth. The obtained results demonstrate the potentiality of active lock-in thermography as a contactless measurement tool for the evaluation of crack depths up to 3 mm.
关键词： Infrared thermography,crack sizing,non-destructive testing,laser heating,crack depth,lock-in thermography
更新于2025-09-12 10:27:22
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Visualizing the Pharmacologic Preconditioning Effect of Botulinum Toxin Type A by Infrared Thermography in a Rat Pedicled Perforator Island Flap Model
摘要： Background: Surgical delay can improve flap viability, leading to vasodilation, neovascularization, and vessel reorganization. Experiments suggest a similar positive effect of botulinum toxin type A on pedicled flap viability. However, whether it may convert choke anastomoses into true anastomoses and how to identify the optimal timing for flap transfer remain unclear. Methods: One hundred fifty-four Sprague-Dawley rats were divided into a control group, three saline injection groups, and three botulinum toxin type A injection groups defined by time of injection (2, 3, and 4 weeks before flap harvest). A pedicled 11 × 3-cm flap was marked on the unilateral dorsum of each rat. Before flap harvest, the flap donors were assessed by infrared thermal imaging, postmortem arteriography, immunohistochemical staining of CD31, and enzyme-linked immunosorbent assay. Flap survival area percentage was measured on postoperative day 7. Results: In the control and saline groups, infrared thermography showed three independent white hotspots interspaced by red zones over flaps, whereas it presented a continuous white band in the botulinum toxin type A groups. There was a significant increase in flap survival area, flap surface temperatures, numbers of identifiable vessels in the choke zones, microvascular density, and vascular endothelial growth factor concentration in the botulinum toxin type A groups. Conclusions: Botulinum toxin type A can convert choke anastomoses into true anastomoses, and its preconditioning effect cannot increase over time; it is appropriate to choose the timing point when the infrared thermal images show a continuous white band existing over flaps for flap transfer.
关键词： pedicled perforator island flap,flap viability,surgical delay,botulinum toxin type A,infrared thermography
更新于2025-09-12 10:27:22
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Photovoltaic defect classification through thermal infrared imaging using a machine learning approach
摘要： This study examines a deep learning and feature-based approach for the purpose of detecting and classifying defective photovoltaic modules using thermal infrared images in a South African setting. The VGG-16 and MobileNet models are shown to provide good performance for the classification of defects. The scale invariant feature transform (SIFT) descriptor, combined with a random forest classifier, is used to identify defective photovoltaic modules. The implementation of this approach has potential for cost reduction in defect classification over current methods.
关键词： photovoltaic,SIFT,machine learning,defect classification,random forest,deep learning,support vector machine,defect detection,infrared thermography
更新于2025-09-12 10:27:22
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Influence of oscillation frequency and focal diameter on weld pool geometry and temperature field in laser beam welding of high strength steels
摘要： As weld pool geometry and thermomechanical strains are known to affect formation of solidification cracks, the influence of a superimposed beam oscillation on these characteristics is investigated for this paper. In this context the effects of the oscillation frequency and focal diameter on the weld pool and temperature field are determined by means of infrared thermography. As a result an increase of the weld pool size for larger focal diameters and a more even shape of the seam edges for higher frequencies can be identified.
关键词： infrared thermography,beam oscillation,laser beam welding,solidification conditions,temperature field,weld pool geometry,high strength steels
更新于2025-09-12 10:27:22