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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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Pediatric Epilepsy Surgery (Preoperative Assessment and Surgical Treatment) || 70 Stereotactic Laser Ablation for Hypothalamic Hamartomas
摘要： MR-guided laser interstitial thermal therapy, or stereotactic laser ablation (SLA), is a minimally invasive approach to the treatment of hypothalamic hamartoma that has been adopted in recent years. This approach utilizes MR thermography to allow near real-time monitoring of tissue destruction to increase the safety profile of thermal ablation. Preoperative workup and patient selection should involve a multidisciplinary epilepsy team. Technical considerations including choice of equipment, trajectory planning, safety mechanisms, and image-guided monitoring are discussed. An initial series of 59 SLAs for hypothalamic hamartoma demonstrated that 93% of the patients were free of their gelastic seizures at 1 year, and 86% of the patients were free of gelastic seizures at last follow-up. MR-guided SLA represents a significant improvement in the risk-to-benefit ratio in the treatment of children with this highly resistant and developmentally devastating epilepsy. Although not all patients are ideal candidates for laser ablation, the improved complication profile of laser ablation makes this approach the ideal first surgery for most hypothalamic hamartomas.
关键词： MR thermography,gelastic seizure,hypothalamic hamartoma,laser interstitial thermal ablation
更新于2025-09-16 10:30:52
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Defect detection in additively manufactured titanium prosthesis by flying laser scanning thermography
摘要： Metal additive manufacturing is nowadays a well-established technology for cutting edge applications in the automotive, aerospace, defense and medical sectors. Since additive metal deposition is basically a welding method, which creates parts by successively adding layers of material, there is a chance for defects like pores, cracks, inclusions and lack of fusion to develop. As a matter of fact, interlayer and intralayer defects are often observed in additive manufactured components. However, if one considers the typical end applications along with the high costs involved in metal additive manufactured components, a “zero defect” target is close to mandatory for this technology. Planning an inclusion of the integrity assessment right into the additive manufacturing process would allow for quick corrective actions to be performed before the component is completed. Some effort has been spent in the quest of an efficient in-process flaw inspection, however, no conventional nondestructive testing (NDT) approach has been fully satisfying yet. This work suggests an experimental evaluation of the effectiveness of flying laser scanning thermography, when detecting flaws on an Additively Manufactured acetabular cup prosthesis made in titanium alloy, where some defects have been artificially created. The rough surface scanned is what’s typically left by the additive manufacturing process, and has been left so in order to prove the efficacy of the NDT inspection in real conditions. Potential benefits and limitations of the technique are discussed.
关键词： IR Thermography,Laser thermography,Additive Manufacturing,Defect Sensitivity
更新于2025-09-12 10:27:22
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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-thermal (PVT) technology: Review and case study
摘要： Nowadays, solar technology converts solar energy into electricity and heat separately. For electricity generation, the main obstacle is the fact that the photovoltaic cells produce less energy as the temperature increases. To overcome this, cooling techniques can be used to raise the efficiency of solar cells, in order to obtain greater power generation. The photovoltaic-thermal hybrid solar collector (or PVT) is an equipment that integrates a photovoltaic (PV) module, for the conversion of solar energy into electrical energy, and a module with high thermal conversion efficiency (T), which employs a thermal fluid. This optimization of solar conversion technology has the main objective of cooling the photovoltaic cells, for increased generation of electricity, while also resulting in useful thermal energy from the working fluid, therefore constituting a cogeneration equipment. The present work reviews the development and global panorama of PVT technology. Afterwards, a case study of a PVT system is presented, together with a theoretical and experimental study. A thermography analysis performed in this PVT system is also examined, which allows for a real-time study of its operating regimes in different conditions, mainly of its thermal behaviour, and for the diagnosis of hot spots that signal potential defects in the cells.
关键词： thermography analysis,Photovoltaic-thermal (PVT) technology,solar energy,hybrid solar collector
更新于2025-09-12 10:27:22
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Accurate Determination of Laser Spot Position during Laser Powder Bed Fusion Process Thermography
摘要： High-speed thermography is useful tool for researching the laser powder bed fusion process by providing thermal information in heat affected zone. However, it is not directly possible to ascertain the position of the laser spot with respect to the melt pool, which could provide key information regarding how laser energy is distributed and absorbed. In this paper, we demonstrate a procedure for registering the laser spot position with the melt pool using a bright illumination source co-axially aligned with the laser to project a sharp spot on the build plane. This spot is fixed to the laser position and used as a reference frame for registering the laser spot with the melt pool radiance temperature distribution. Measurement results demonstrate the effect of varying process parameters (laser power and scan speed) on the melt pool thermal field and respective position of the laser spot.
关键词： additive manufacturing,Laser powder bed fusion,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
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Selective laser beam melting of polymers: In situ and offline measurements for process adapted thermal characterization
摘要： Selective laser beam melting of polymers has to overcome the borders between pure prototype construction and the manufacturing of serial parts. Therefore, a high level of reproducibility of the generated components must be ensured. Up to now, the thermal history of a component during selective laser beam melting is unknown. Neither the temperature during exposure of one layer nor the temperature development in z- or build direction is detected or even regulated. Therefore, in this study the temperature during laser exposure will be detected in a dual approach. The fundamental material beam interaction will be analyzed with a specific test set up, the so-called Laser-HS-DSC. This allows the detection of material beam interactions in combination with a commercial DSC experiment to analyze whether degradation occurs or not. With in situ infrared measurements in a selective laser beam melting system the maximum temperature during laser exposure can be measured. Finally, the offline Laser-HS-DSC experiments are compared to resulting maximum temperatures during exposure in a selective laser beam melting system. The same tendencies of maximum temperatures with varying energy input are obtained, whereas the maximum levels differ due to the different amount of exposed particles.
关键词： PA12,thermography,Additive manufacturing,process-oriented thermal analysis,process characterization,laser-flash DSC,selective laser melting
更新于2025-09-12 10:27:22