- 标题
- 摘要
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- 实验方案
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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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Characterization of a vertical crack using Laser Spot Thermography
摘要： This paper deals with the solution of an inverse problem for the heat equation aimed at nondestructive evaluation of fractures, emerging on the accessible surface of a slab, by means of Active Thermography. In real life, this surface is heated with a laser and its temperature is measured for a time interval by means of an infrared camera. A fundamental step in iterative inversion methods is the numerical solution of the underlying direct mathematical model. Usually, this step requires specific techniques in order to limit an abnormal use of memory resources and computing time due to excessively fine meshes necessary to follow a very thin fracture in the domain. Our contribution to this problem consists in decomposing the temperature of the damaged specimen as a sum of a term (with known analytical form) due to an infinite virtual fracture and the solution of an initial boundary value problem for the heat equation on one side of the fracture (i.e. on a rectangular domain). The depth of the fracture is a variable parameter in the boundary conditions that must be estimated from additional data (usually, measurements of the surface temperature). We apply our method to the detection of simulated cracks in concrete and steel specimens.
关键词： finite elements,heat equation,crack,Inverse problems,active thermography
更新于2025-09-19 17:13:59
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Automatic detection of photovoltaic module defects in infrared images with isolated and develop-model transfer deep learning
摘要： With the rising use of photovoltaic and ongoing installation of large-scale photovoltaic systems worldwide, the automation of photovoltaic monitoring methods becomes important, as manual/visual inspection has limited applications. This research work deals with automatic detection of photovoltaic module defects in Infrared images with isolated deep learning and develop-model transfer deep learning techniques. An Infrared images dataset containing infrared images of normal operating and defective modules is collected and used to train the networks. The dataset is obtained from Infrared imaging performed on normal operating and defective photovoltaic modules with lab induced defects. An isolated learned model is trained from scratch using a light convolutional neural network design that achieved an average accuracy of 98.67%. For transfer learning, a base model is first developed (pre-trained) from electroluminescence images dataset of photovoltaic cells and then fine-tuned on infrared images dataset, that achieved an average accuracy of 99.23%. Both frameworks require low computation power and less time; and can be implemented with ordinary hardware. They also maintained real time prediction speed. The comparison shows that the develop-model transfer learning technique can help to improve the performance. In addition, we reviewed different kind of defects detectable from infrared imaging of photovoltaic modules, that can help in manual labelling for identifying different defect categories upon access to new huge data in future studies. Last of all, the presented frameworks are applied for experimental testing and qualitative evaluation.
关键词： Isolated deep learning,Develop-model transfer deep learning,Automatic defect detection,Thermography,Infrared images,Photovoltaic (PV) modules
更新于2025-09-19 17:13:59
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Influence of Solidification Conditions on the Microstructure of Laser-Surface-Melted Ductile Cast Iron
摘要： The thermal conditions in the molten pool during the laser surface melting of ductile cast iron EN-GJS-700-2 were estimated by using infrared thermography and thermocouple measurements. The thermal data were then correlated with the microstructure of the melted zone. Additionally, the thermodynamic calculations of a Fe-C-Si alloy system were performed to predict the solidification path of the melted zone. It was found that increasing the cooling rate during solidification of the refined ledeburite eutectic but also suppressed the martensitic transformation. A continuous network of plate-like secondary cementite precipitates and nanometric spherical precipitates of tertiary cementite were observed in regions of primary and eutectic austenite. The solidification of the melted zone terminated with the Liquid → γ-Fe + Fe3C + Fe8Si2C reaction. The hardness of the melted zone was affected by both the fraction of the retained austenite and the morphology of the ledeburite eutectic.
关键词： laser surface melting,ductile cast iron,cooling rate,thermography,tertiary cementite,secondary cementite
更新于2025-09-19 17:13:59
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Loss Analysis in Perovskite Photovoltaic Modules
摘要： Hybrid metal-halide perovskite-based thin-film photovoltaics (PVs) have the potential to become the next generation of commercialized PV technology with certified power conversion efficiencies reaching 24% on devices having 0.1 cm2 area. Recent efforts in upscaling this technology result in an efficiency of 12.6% for 354 cm2 modules. However, upscaling loss for perovskite-based PVs is higher than for any other PV technology. In this study, upscaling losses of devices with aperture area 0.1, 4, and 100 cm2 are investigated, with a focus on layer inhomogeneities. Electroluminescence, dark lock-in thermography, microphotoluminescence spectroscopy, and electron spectroscopy are used to analyze and group layer inhomogeneities with a minimal size of 10 μm and to compare loss mechanisms for radial and linear deposition techniques. Analysis results help to identify current processing pitfalls, where understanding and control of perovskite crystal formation plays the crucial role.
关键词： loss characterization,thermography,perovskite thin-film photovoltaic modules,luminescence
更新于2025-09-19 17:13:59
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[IEEE 2020 IEEE/SICE International Symposium on System Integration (SII) - Honolulu, HI, USA (2020.1.12-2020.1.15)] 2020 IEEE/SICE International Symposium on System Integration (SII) - Calibration of Laser Optics for Sensor Guided Remote Cutting
摘要： In the last several years, laser based material processing has established itself in many industrial branches as an economical manufacturing process. Laser remote cutting in particular is widespread in the automotive sector. In order to take full advantage of laser remote cutting, it is necessary to position the laser beam precisely on the workpiece using a handling kinematic system. Therefore, this work focuses on the combination of standard industrial robots with laser scanner optics. To address this configuration, this paper proposes a method for the calibration of the parameters, which describe the precise position of the 3D laser scanner optics in respect to the robot. Moreover, the robot introduces a new source of deviation, which is then compensated by using an external measuring system to guide the scanner optics during processing.
关键词： thermography,remote laser scanner optics,machining,calibration,automation,digital image processing
更新于2025-09-19 17:13:59
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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 - Complex experimental approach to carbon-carbon composite defect detection by laser vibrometry and optical thermography
摘要： Nondestructive testing of carbon-carbon composite plate by thermal method and laser vibrometry with 12 impact damages of the same energy were carried out. Thermograms and distributions of vibrations from the plate surface at its heating and acoustic excitation are obtained. Complex diagnostics made it possible to detect all available defects by synthesizing data, as well as to increase the accuracy and informative value of quality control. It is shown that the control efficiency depends on the side of the plate selected for shooting, the type of method used to process the obtained data in the thermal control, as well as on the choice of the direction of acoustic wave movement when using laser vibrometry.
关键词： laser vibrometry,carbon-carbon composite,optical thermography,nondestructive testing,defect detection
更新于2025-09-16 10:30:52
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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