Статті в журналах: "Thermal flaw detection"

1

McLaughlin, P. V., M. G. Mirchandani, and P. V. Ciekurs. "Infrared Thermographic Flaw Detection in Composite Laminates." Journal of Engineering Materials and Technology 109, no. 2 (April 1, 1987): 146–50. http://dx.doi.org/10.1115/1.3225954.

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Research performed to develop thermography as a routine rapid flaw detection tool for large composite structures is presented. The externally applied thermal field (EATF) technique is described whereby surface cracks or sub-surface impact damage creates detectable surface temperature perturbations when heated. EATF thermographic procedures and flaw detection capabilities in multidirectional and unidirectional graphite and glass fiber composites are described. The method’s advantages and limitations are outlined.

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2

Maldague, Xavier P. "Subsurface flaw detection in reflective materials by thermal-transfer imaging." Optical Engineering 30, no. 1 (1991): 117. http://dx.doi.org/10.1117/12.55760.

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3

Nucera, Claudio, Robert Phillips, and Francesco Lanza di Scalea. "Ultrasonic Guided Wave Monitoring of Railroad Tracks." Advances in Science and Technology 83 (September 2012): 198–207. http://dx.doi.org/10.4028/www.scientific.net/ast.83.198.

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Among structural concerns for the safety of rail transportation are internal flaws and thermal stresses, both of which can cause disruption of service and even derailments. Ultrasonic guided waves lend themselves to addressing both of these problems. This paper reports on two inspection systems for rails being developed at UCSD under the auspices of the US Federal Railroad Administration. Both systems utilize ultrasonic guided waves as the main probing mechanism, for the two different applications of flaw detection and thermal stress detection.

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4

Kaufmann, Guillermo H., Matías R. Viotti, and Gustavo E. Galizzi. "Flaw Detection Improvement in Temporal Speckle Pattern Interferometry Using Thermal Waves." Journal of Holography and Speckle 1, no. 2 (June 1, 2004): 80–84. http://dx.doi.org/10.1166/jhs.2004.011.

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5

Kaufmann, Guillermo H. "Flaw detection using lock-in temporal speckle pattern interferometry and thermal waves." Optical Engineering 46, no. 11 (November 1, 2007): 115601. http://dx.doi.org/10.1117/1.2801725.

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6

Kozelskaya, S. "Integrated thermal flaw detection technology of complex spatial composite structures in operation." Journal of Physics: Conference Series 1636 (September 2020): 012023. http://dx.doi.org/10.1088/1742-6596/1636/1/012023.

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7

Komolikov, Yu I., S. E. Chernykh, I. D. Kashcheev, and V. N. Kostin. "Flaw detection of tubural refractory products by the method of thermal testing." NOVYE OGNEUPORY (NEW REFRACTORIES), no. 9 (November 24, 2021): 55–57. http://dx.doi.org/10.17073/1683-4518-2021-9-55-57.

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8

Yang, Ping, Ge Jing, and Cui Ming Li. "The Calculation and Analysis of the Infrared Thermal Wave Nondestructive Testing for the Defects of the Parts in the Turnout Point Switch." Applied Mechanics and Materials 328 (June 2013): 393–99. http://dx.doi.org/10.4028/www.scientific.net/amm.328.393.

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This paper did quantitive flaw detection research to the defective parts of turnout point switch by using infrared thermal wave nondestructive testing based of the theory of infrared nondestructive testing. By using ANSYS, I made the numeric simulation test to parts of the inside known defection point switch, and made calculation and analysis for the result of this numeric simulation test. The result demonstrated that this method can achieve the quantitive infrared thermal wave nondestructive testing to defective parts of point switch.

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9

Li, Zhuo Qiu, Xiong Zhang, and Jiang Tao Zhang. "Solution of Transient Temperature Field for Thermographic NDT Under Joule Effect Heating." Journal of Heat Transfer 127, no. 7 (January 6, 2005): 670–74. http://dx.doi.org/10.1115/1.1924625.

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Conducting infrared thermographic nondestructive testing (NDT) by the internal heat generated by Joule effect of components is a new heating approach for flaw detection. Due to the combination of electric field and thermal field, the irregular geometric boundary and the complicated internal heat source distribution, the theoretical solution of transient temperature field is very difficult. Nowadays numerical solution by FEM and FDM is mainly applied. By adopting certain assumptions, this paper presents a method to obtain the approximate temperature field by using Green’s function, and gives the solution of a two-dimensional rectangular field including a circular flaw. By contrast, the result tallies with the FEM results well.

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10

Tang, Jin Jun, Cui Liang, and Chen Guang Xu. "Effect of Pore Defect Size and Location on Damage Tolerance of Aluminum Alloy Piston and Fiber Ring Groove." Materials Science Forum 1053 (February 17, 2022): 205–11. http://dx.doi.org/10.4028/p-tm5h6i.

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The defects of high-power density piston aluminum alloy components involved in this paper include surface crack, internal crack, shrinkage cavity and cold shut. The service condition of piston components is 350°C-420°C, and the explosion pressure of piston crown is 28Mpa. The requirements for eddy current flaw detection of this component are in accordance with a and requirements in GB / T5126-2013 eddy current flaw detection standard, that is, it is not allowed to be greater than 0.12mm × 0.2mm × 3mm volumetric defects, and Ф1.0mm flat bottom hole equivalent point defect. For the piston components of 88kw / L high-power diesel engine, under the service conditions of temperature 350°C-420°C and piston top explosion pressure 28Mpa. Under the condition of thermal mechanical coupling, the typical NDT defects such as surface crack, internal crack, shrinkage cavity and cold shut of the first ring groove and internal position of the piston are studied. On scale, morphology and position sensitivity and their quantitative relationship. At the same time, numerical simulation analysis combined with relevant experimental verification is used to comprehensively analyze and evaluate the damage tolerance of defects, and scientifically evaluate the defects of different properties and sizes.

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11

Karpov, D. "APPLICATION OF ACTIVE AND PASSIVE THERMAL CONTROL IN DEFECTOSCOPY OF CONSTRUCTION MATERIALS AND PRODUCTS, FILLER STRUCTURES OF BUILDINGS AND CONSTRUCTIONS." Construction Materials and Products 2, no. 4 (June 27, 2020): 39–44. http://dx.doi.org/10.34031/2618-7183-2019-2-4-39-44.

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one of the perspective and modern methods of nondestructive testing – thermal control is considered. The possibilities and advantages of thermal control in the identification of defects in various building materials and products, enclosing structures of buildings and structures are given. The short characteristics of the main defects of building materials and products, buildings and structures are proposed. The basic principles of identification of hidden (invisible) and obvious (visible) defects are briefly considered and practical results of construction flaw detection of objects for various purposes with the use of thermal imaging equipment are presented. On the example of a fragment of the enclosing building structure of piece building products in the form of ceramic bricks with artificially created technical defects in the process of qualitative analysis of thermograms zone of thermal temperature anomalies (method of active thermal control) are localized. For some enclosing structures of buildings and structures based on the results of thermal imaging identified obvious thermal defects, their qualitative analysis and recommendations for elimination (method of passive thermal control) are made.

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12

Chulkov, A. O., D. A. Nesteruk, B. I. Shagdyrov, and V. P. Vavilov. "Method and Equipment for Infrared and Ultrasonic Thermographic Testing of Large-Sized Complex-Shaped Composite Products." Russian Journal of Nondestructive Testing 57, no. 7 (July 2021): 619–26. http://dx.doi.org/10.1134/s1061830921070044.

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Abstract The robotic equipment for and the technique of combined thermal nondestructive testing (NDT) of large-sized products by zones with subsequent data synthesis are described. The effectiveness of the combination of two methods, infrared and ultrasonic thermographic testing, is shown by the example of the developed complex-shaped reference sample with 18 simulators of production and operational defects. The developed algorithms for the synthesis of test results, including spatial “matching” of a set of thermograms and automated flaw detection and defect characterization with the use of neural networks have illustrated the effectiveness of the proposed approach for practical application.

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13

Storozhenko, Volodymyr, Roman Orel, and Aleksandr Mjagky. "Optimization of the procedure of thermal flaw detection of the honeycomb constructions by improving the accuracy of interference function." Eastern-European Journal of Enterprise Technologies 5, no. 5 (83) (October 30, 2016): 12–18. http://dx.doi.org/10.15587/1729-4061.2016.79563.

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14

Kareva, Nadezhda T., Djomi T. Chungakov, and Nikita A. Zavartsev. "The Research of Heat-Resistant Layer Defects Formed during the Surfacing of Nickel Alloy on the Exhaust Valve Chamfer." Materials Science Forum 989 (May 2020): 133–38. http://dx.doi.org/10.4028/www.scientific.net/msf.989.133.

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The final set of properties of the exhaust valve is formed in the course of the entire set of processes, the most important is the build-up of the valve chamfer which is subjected to constant high temperatures, gas flow and thermal cycling, therefore strict adherence to the whole complex of properties is necessary. In the study two materials were investigated: the deformable part of the base material (steel grade 40X10C2M (EN steel grade X40CrSiMo10)) and surfacing (alloy EP616A), used to manufacture the exhaust valve of the internal-combustion engine.The study was carried out at different stages of valve manufacturing: after electro-forging during the formation of a valve head from a rod, subsequent heat treatment (quenching + high tempering), after surfacing a ring with the heat-resistant alloy. The chemical composition of phases, inclusions, and sections of EP616A alloy around the shrink-hole were determined by the method of micro-X-ray analysis. The results indicate a shortage of visual inspection, and that conducting a selective destructive method does not ensure the full probability of detecting internal defects. It is advisable instead of destructive control to introduce ultrasonic flaw detection.

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15

Derkachev, Igor, Alexander Kustov, Mikhail Kulakov, and Oleg Baklanov. "Monitoring of Properties Subjected to Innovative Technological Treatments of Subsurface Layers of Materials by AMD-Methods." Key Engineering Materials 910 (February 15, 2022): 713–19. http://dx.doi.org/10.4028/p-w8c19g.

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In this paper, it is proposed to use modern research AMD-methods to monitor the properties of the subsurface layers of materials subjected to innovative technological treatments. They are based on the analysis of the parameters of acoustic waves reflected from the subsurface layers of the studied materials. The technological processing leads to a change in the acoustic characteristics, the value of which is calculated by the values of the parameters of the material of the samples. The effectiveness of the application of methods of acoustic-microscopic flaw detection for the analysis of the state of materials after thermal, chemical, deformation, and diffusion effects is demonstrated.

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16

Qu, Xiu Jie, Fu Zhang, and Ying Zhang. "Feature-Level Fusion of Dual-Band Infrared Images Based on Gradient Pyramid Decomposition." Applied Mechanics and Materials 347-350 (August 2013): 2380–84. http://dx.doi.org/10.4028/www.scientific.net/amm.347-350.2380.

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Infrared thermal imager has been widely used in the fields of missile guidance and flaw detection. To identify the target clearly, the advanced one adopts dual bands sensors to capture images. Since of that, there is an urgent need of a fusion of the dual-bands images. The fused result includes much more exhaustive information than any single one, and can better reflect the actual. Among the algorithms used to fuse the dual-band infrared images, the weighted algorithm is the most widely used and easiest to be achieved. Nonetheless, its effect is not desired. We extract the features of the source images and make a fuse based on them on the feature-level. To get a better result, in this paper, the fusion strategy based on the Gradient pyramid transform has been mainly adopted. Meanwhile, there is a comparison with the weighted algorithm. Also, it makes an evaluation and analysis to the experimental data, and finally obtains the desired results.

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17

Бобко, Yuriy Bobko, Синчугов, and Ilya Sinchugov. "Nondestructive Testing of Composite Structures Specimens by Shearography." NDT World 19, no. 4 (December 15, 2015): 4–7. http://dx.doi.org/10.12737/23494.

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New composite materials call for a new approach to the nondestructive testing. The goal of this article is to show the advantages of shearography in comparison with other testing methods. The article describes the main principles of shearography as one of the interferometric methods. Applying various types of loading (thermal, mechanical, vibration, pressure, etc.) makes it possible to visualize various types of defects. High sensitivity and operativeness of the noncontact method, possibility of using many types of loading on the tested samples, non-contact testing of the object in question, and the possibility of testing large areas simultaneously determine the main advantages of the shearography method. The authenticity of the flaw detection grows when use is made of loading that resembles the operating conditions of the objects, which makes it possible to estimate the defect behavior in the specific operating conditions. The article provides the reader with an account of the main types of equipment, its limitations and features. Applications of shearography enable the user both to substantially optimize and check-out the production and monitor the objects in operation. Shearography can also serve as an input testing tool.

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18

Bosomworth, Chris, Maksym Spiryagin, Sanath Alahakoon, and Colin Cole. "MODELLING RAIL THERMAL DIFFERENTIALS DUE TO BENDING AND DEFECTS." Transport 36, no. 2 (June 10, 2021): 134–46. http://dx.doi.org/10.3846/transport.2021.14574.

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Rail foot flaws have the potential to cause broken rails that can lead to derailment. This is not only an extremely costly issue for a rail operator in terms of damage to rolling stock, but has significant flow-on effects for network downtime and a safe working environment. In Australia, heavy haul operators run up to 42.5 t axle loads with trains in excess of 200 wagons and these long trains produce very large cyclic rail stresses. The early detection of foot flaws before a broken rail occurs is of high importance and there are currently no proven techniques for detecting rail foot flaws on trains at normal running speeds. This paper shall focus on the potential use of thermography as a detection technique and begin investigating the components of heat transfer in the rail to determine the viability of thermography for detecting rail foot flaws. The paper commences with an introduction to the sources of heat generation in the rail and modelling approaches for the effects of bending, natural environmental factors and transverse defects. It concludes with two theoretical case studies on heat generated due to these sources and discusses how they may inform the development of a practical thermography detection methodology.

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19

Huang, Haibo, Wenlei Sun, Yong Huang, and Jiangtong Yu. "Properties of Curved Parts Laser Cladding Based on Controlling Spot Size." Applied Sciences 10, no. 2 (January 20, 2020): 728. http://dx.doi.org/10.3390/app10020728.

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In this study, a method based on controlling the laser spot size was proposed in the process of curved parts laser cladding, and the coatings obtained by this method were analysed through investigation of the microstructure, microhardness, adhesion property and wear resistance properties. The nonuniform rational B-spline surface (NURBS) reconstruction method was used to obtain the workpiece geometrical characteristics of laser cladding, and through the establishment of a mathematical model, the process of the laser beam working on the curved surface was simplified as the intersection of the cylinder and curvature sphere. Then, the spot size was transformed into the area of a cylinder intersecting with a sphere, and by adjusting the laser head, the size of the laser spot was controlled in the threshold and interpolation points were obtained. The laser cladding trajectory was ensured by these interpolation points, and the experiment was carried out to study the properties of the coating. The results showed that the average coating thickness was about 1.07 mm, and the fluctuation of coating thickness did not exceed 0.05 mm; also, there were no cracks or pores in the layer after penetrant flaw detection. The SEM showed that the grains passed through the transition of plane crystal, cellular crystal, dendrite and equiaxed crystal from the bottom to the top of the layer. After 30 cycles of thermal shock tests, the cladding layer was still well bonded with the substrate and the microhardness and wear resistance were 2 times and 1.4 times higher than that of substrate, respectively.

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20

Chaban, N. I., I. V. Rybitskyi, M. O. Karpash, and V. D. Myndiuk. "APPROBATION AND ANALYSIS OF EXPERIMENTAL RESEARCHES'S RESULTS OF THE EXTENDED METHOD OF PHYSICAL-MECHANICAL CHARACTERISTICS STEELS'S CONTROL." Prospecting and Development of Oil and Gas Fields, no. 4(69) (November 29, 2018): 37–49. http://dx.doi.org/10.31471/1993-9973-2018-4(69)-37-49.

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Most of the oil and gas equipment complex is subjected to cyclic-variable, mechanical, thermal loads and corrosive-active environment. These effects causing a change in the structural statr of the metal contribute to the accelerated development of defects, especially in places with stress concentrators, which ultimately lead to the constructions destruction. Available ultrasonic, electromagnetic, and eddy-current non-destructive testing methods are currently aimed at solving defect detection problems. However, it is more important to timely identify the initial stage of the process of damage accumulation in a metal by determining changes in the structural state of the metal. The article proposes a methodology for studies of steel structural changes arising in the process of exploitation and their impact on mechanical characteristics. A reasonable choice of the optimal indicator characterizing the image of the acoustic structural noise of the material obtained by applying ultrasonic flaw detector in a complete set with piezoelectric converters with a phased array is substantiated. The complex of physical and mechanical parameters of the investigated samples are measured and the results obtained were analyzed. The modern methods of determination of mechanical characteristics of steels are considered, their deficiencies are determined and the methods of their optimization are proposed. The regression-correlation analysis of the experimental studies results was carried out, which resulted in the equation of dependence between a set of non-destructive control parameters and mechanical characteristics of steels was obtained. In order to verify the adequacy of the proposed model and to establish the possibility of controlling the casing and tubing on the samples made, series of experimental studies were carried out, which confirmed the reliability of the resulting calculation model for determining the mechanical characteristics of the steels by using two informative parameters, namely hardness and integral density of images of acoustic structural noise.

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21

Kim, Changmin, Jae-Sol Choi, Hyangin Jang, and Eui-Jong Kim. "Automatic Detection of Linear Thermal Bridges from Infrared Thermal Images Using Neural Network." Applied Sciences 11, no. 3 (January 20, 2021): 931. http://dx.doi.org/10.3390/app11030931.

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Detecting thermal bridges in building envelopes should be a priority to improve the thermal performance of buildings. Recently, thermographic surveys are being used to detect thermal bridges. However, conventional methods of detecting thermal bridges from thermal images rely on the subjective judgment of audits. Research has been conducted to automatically detect thermal bridges from thermal images to improve problems caused by such subjective judgment, but most of these studies are still in the early stage. Therefore, this study proposes a linear thermal bridge detection method based on image processing and machine learning. The proposed method includes thermal anomaly area clustering, feature extraction, and an artificial-neural-network-based thermal bridge detection. The proposed method was validated by detecting the thermal bridges in actual buildings. As a result, the average precision, recall, and F-score were 89.29%, 87.29, and 87.63%, respectively.

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22

Ткач, Михаил Романович, Юрий Григорьевич Золотой, Ирина Юрьевна Жук, Юрий Николаевич Галинкин, Аркадий Юрьевич Проскурин та Владимир Сергеевич Ключник. "Экспериментальное определение вибрационных характеристик рабочих лопаток турбин помехоустойчивым цифровым спекл-интерферометром". Aerospace technic and technology, № 4sup2 (27 серпня 2021): 52–61. http://dx.doi.org/10.32620/aktt.2021.4sup2.07.

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The paper notes the wide possibilities and high efficiency of vibration diagnostics of parts and assemblies of power units by the method of electronic speckle interferometry (ESI), shows the feasibility of developing and improving methods for obtaining speckle interferograms of vibrating objects. A patented by the authors' scheme of a digital speckle interferometer (DSI) for determining the dynamic parameters of products is presented. The diffuse reference wave greatly simplifies its alignment, mainly the aligned channels of propagation of interfering beams determine the resistance to mechanical and thermal disturbances, and the separate beam splitter and diffuser make it easy to optimize the optical scheme for the object under study. Speckle interferograms are obtained by speckle correlation methods and a developed method for determining the contrast of the dynamic speckle pattern. It does not impose special requirements on the parameters of the video system, does not require the use of a specialized video camera, and allows, by using a rotary platform, to organize a panoramic view of the oscillatory forms of asymmetric structures. The use of this method in combination with the proposed optical scheme provides an express analysis of products in off-bench conditions. The increased noise immunity of the installation allows the determination of the spectrum of frequencies and vibration modes (SFVM) of samples under free boundary conditions, which is rarely realized in interferometry. The paper presents examples of such speckle interferograms, the expediency of obtaining which is important in the resonance study of the elastic properties of the material and vibration resonance flaw detection. The implemented software and hardware solutions increase the resolution and visibility of the band patterns; facilitate their quantitative interpretation and the extraction of numerical information on the distribution of vibration amplitudes. The area of scientific interests and the specificity of the author's developments have determined the preferential adaptation of the proposed device with a complex of software and methodological developments for vibration testing of gas turbine engine (GTE) blades.

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23

Lisowska-Lis, Agnieszka, and Piotr Siudut. "Detection of ammonia leak in laboratory conditions using a FLIR 306 camera and a portable gas detector." Science, Technology and Innovation 8, no. 1 (August 30, 2020): 35–41. http://dx.doi.org/10.5604/01.3001.0014.3703.

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The study aimed to analyse detection methods of ammonia leakage by various electrical methods. Rapid detection of the escape of hazardous technical gases is extremely important in large chemical plants. The basis of the research was the use of a specialized camera, model FLIR GF306, to detect a leak of selected gases in a narrow infrared band. In laboratory conditions, the controlled emission of gaseous ammonia at various concentrations was simulated, and gas detection was performed: a) using a narrow infrared thermography method, and b) by a portable electrochemical detector dedicated to detecting ammonia. The turbulent flow of gas into the environment and high thermal contrast between the expanding gas and the background are the conditions for effective gas detection with a thermal imaging camera operating in a narrow infrared band.

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24

Shen, Xiao Mei, and Ju Wu Xu. "Research on Method of Building Energy Conservation Based on Infrared Imaging Measurement." Advanced Materials Research 512-515 (May 2012): 2899–903. http://dx.doi.org/10.4028/www.scientific.net/amr.512-515.2899.

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With the deepening of the energy conservation of the building, energy saving from the original design of building energy-saving gradually turned to the field detection and completion acceptance, which requires a corresponding energy-efficient means of detection. With the development of infrared technology, the combination of infrared technology and detection methods of building energy-saving, to further promote the development of building energy efficiency testing work. Compared to the traditional heat flow meter or hot-box method, infrared thermal imaging method has no effect on the measured object, detecting the surface temperature of quick reaction speed, accompanying with wide temperature range and high precision, is widely used in various fields of testing work, which has been particularly prominent in the thermal defect detection. In this paper, the method of infrared thermography is used to confirm whether the thermal defects exist in energy-saving construction or not. Testing results show that infrared thermography can accurately reflect the temperature distribution of building wall surface. Infrared thermal imaging to detect the building surface's energy efficiency, which is providing efficient and accurate means of detection for the evaluation of the building energy efficiency. This is to help carry out a comprehensive building energy-saving testing.

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25

Deilamsalehy, Hanieh, Timothy C. Havens, Pasi Lautala, Ezequiel Medici, and James Davis. "An automatic method for detecting sliding railway wheels and hot bearings using thermal imagery." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 231, no. 6 (March 22, 2016): 690–700. http://dx.doi.org/10.1177/0954409716638703.

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One of the most important safety-related tasks in the rail industry is an early detection of defective rolling stock components. Railway wheels and wheel bearings are the two components prone to damages due to their interactions with brakes and railway track, which makes them a high priority when the rail industry investigates improvements in the current detection processes. One of the specific wheel defects is a flat wheel, which is often caused by a sliding wheel during a heavy braking application. The main contribution of this paper is the development of a computer vision method for automatically detecting the sliding wheels from images taken by wayside thermal cameras. As a byproduct, the process will also include a method for detecting hot bearings from the same images. We first discuss our automatic detection and segmentation method, which identifies the wheel and bearing portion of the image. Then, we develop a method, using histogram of oriented gradients to extract the features of these regions. These feature descriptors are later employed by support vector machine to build a fast classifier with a good detection rate, which can detect abnormalities in the wheel. At the end, we train our algorithm using simulated images of sliding wheels and test it on several thermal images collected in a revenue service by the Union Pacific Railroad in North America.

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26

Bedoya-Echeverry, Sebastián, Hernán Belalcázar-Ramírez, Humberto Loaiza-Correa, Sandra Esperanza Nope-Rodríguez, Carlos Rafael Pinedo-Jaramillo, and Andrés David Restrepo-Girón. "Detection of lies by facial thermal imagery analysis." Revista Facultad de Ingeniería 26, no. 44 (January 25, 2017): 45. http://dx.doi.org/10.19053/01211129.v26.n44.2017.5771.

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An artificial vision system is presented for lie detection by analyzing face thermal image sequences. This system represents an alternative technique to the polygraph. Some of its features are: 1) it has no physical contact with the examinee, 2) it is non-intrusive, 3) it has a potential for private use, and 4) it can simultaneously analyze several persons. The proposed system is based on the detection of physiological changes in temperature in the lacrimal puncta area caused by the subtle increase in blood flow through the nearby vascular network. These changes take place when anxiety appears as a consequence of deception. Thus, the system segments the periorbital area, and tracks consecutive frames using the Kanade-Lucas-Tomasi algorithm. The results show a success rate of 79.2 % in detecting lies using a simple classification based on the comparison between the estimated temperatures in control questions, and the rest of the interrogation procedure. The performance of this system is comparable with previous works, where cameras with better specifications were used.

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27

Kapiris, P. G., D. S. Mathioulakis, A. Petropoulos, and G. Kaltsas. "Flow reattachment point detection via thermal sensors - PIVevaluation." Procedia Engineering 25 (2011): 487–90. http://dx.doi.org/10.1016/j.proeng.2011.12.121.

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28

Hameed, Mustafa Q., David Zurakowski, Mark R. Proctor, Scellig S. D. Stone, Benjamin C. Warf, Edward R. Smith, Liliana C. Goumnerova, Marek Swoboda, Tomer Anor, and Joseph R. Madsen. "Noninvasive Thermal Evaluation of Ventriculoperitoneal Shunt Patency and Cerebrospinal Fluid Flow Using a Flow Enhancing Device." Neurosurgery 85, no. 2 (June 16, 2018): 240–49. http://dx.doi.org/10.1093/neuros/nyy246.

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Abstract BACKGROUND While a noninvasive flow determination would be desirable in the diagnosis of cerebrospinal fluid shunt malfunction, existing studies have not yet defined a role for thermal flow detection. OBJECTIVE To evaluate a revised test protocol using a micropumper designed to transiently enhance flow during thermal testing to determine whether thermal detection of flow is associated with progression to shunt revision surgery. METHODS Eighty-two unique tests were performed in 71 shunts. The primary outcome, need for revision within 7 d of testing, was compared with results of micropumper-augmented thermal flow detection. Statistical analysis was based on blind interpretation of test results and raw temperature data recorded during testing. RESULTS The test was sensitive (73%) and specific (68%) in predicting need for revision, with 5.6-fold higher probability of revision when flow was not detected. Negative predictive value in our sample was 94.2%. The probability of not requiring revision increased with increasing total temperature drop. Analysis of various possible thresholds showed that the optimal temperature cutoff may be lower than suggested by the manufacturer (0.125°C vs 0.2°C). CONCLUSION This is the first study to report a strong association between thermal flow evaluation and a clinical impression that a shunt is not malfunctioning. The current recommended threshold may increase the false positive rate unnecessarily, and as clinicians gain experience with the method, they may find value in examining the temperature curves themselves. Multicenter studies are suggested to further define a role for this diagnostic test.

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Iwasaki, Yoichiro, Masato Misumi, and Toshiyuki Nakamiya. "Robust Vehicle Detection under Various Environments to Realize Road Traffic Flow Surveillance Using an Infrared Thermal Camera." Scientific World Journal 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/947272.

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To realize road traffic flow surveillance under various environments which contain poor visibility conditions, we have already proposed two vehicle detection methods using thermal images taken with an infrared thermal camera. The first method uses pattern recognition for the windshields and their surroundings to detect vehicles. However, the first method decreases the vehicle detection accuracy in winter season. To maintain high vehicle detection accuracy in all seasons, we developed the second method. The second method uses tires’ thermal energy reflection areas on a road as the detection targets. The second method did not achieve high detection accuracy for vehicles on left-hand and right-hand lanes except for two center-lanes. Therefore, we have developed a new method based on the second method to increase the vehicle detection accuracy. This paper proposes the new method and shows that the detection accuracy for vehicles on all lanes is 92.1%. Therefore, by combining the first method and the new method, high vehicle detection accuracies are maintained under various environments, and road traffic flow surveillance can be realized.

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30

Dušek, Václav, Milan Šípek, and Pavla Sunková. "Determination of Diffusion Coefficients of Gases Through a Flat Polymeric Membrane by the Method of Non-Linear Regression." Collection of Czechoslovak Chemical Communications 58, no. 12 (1993): 2836–45. http://dx.doi.org/10.1135/cccc19932836.

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Non-linear regression was applied for calculation of diffusion coefficients of gases through a flat polymeric membrane from the experimental data obtained by the flow permeation method with the thermal conductivity detection of composition of gaseous mixture. to verify this method a polyethylene and carbon dioxide was chosen. Diffusion coefficients of carbon dioxide in the low-density polyethylene of two different thickness at the temperature of 25 °C were determined with precision about ±2.5% in agreement with literature.

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31

Ko, Seokcheol, Hyeong-Gon Kang, Sung-Hun Lim, and Byoung-Sung Han. "Superconducting flux flow sensor used for a thermal detection." Sensors and Actuators A: Physical 113, no. 3 (August 2004): 265–69. http://dx.doi.org/10.1016/j.sna.2004.01.009.

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32

Madžgalj, A., M. L. Baesso, and M. Franko. "Flow injection thermal lens spectrometric detection of hexavalent chromium." European Physical Journal Special Topics 153, no. 1 (January 2008): 503–6. http://dx.doi.org/10.1140/epjst/e2008-00494-4.

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33

Yang, Hong Wei, Zheng Xing, and Kao Wen Zhou. "A Sensitive Formaldehyde Sensor Based on Cataluminescence Coupled with Thermal Desorption." Applied Mechanics and Materials 670-671 (October 2014): 1163–66. http://dx.doi.org/10.4028/www.scientific.net/amm.670-671.1163.

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A sensitive cataluminescence-based detecting technology using nanosized Mo4V6Ti10O47 as a probe was proposed for determination of formaldehyde in air. Trace formaldehyde was firstly absorbed on active carbon at room temperature to concentrate, then desorbed at 75°C to determine. The method showed high selectivity to formaldehyde at wavelength of 575nm, satisfying activity at temperature of 260°C and good stability at carrier flow rate of 145 ml/min. The linear range of CTL intensity versus concentration of formaldehyde was 0.04~78 mg/m3, and the detection limit (3σ) was 0.02 mg/m3. The recovery of artificial sample was 96.8%-103.4% by this method. There was no response to CO, CO2, SO2, NH3, methanol, ethanol, benzene, toluene and xylenes.

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Restrepo Girón, Andrés David. "Enhanced method for flaws depth estimation in CFRP slabs from FDTC thermal contrast sequences." Ingeniería e Investigación 35, no. 3 (December 14, 2015): 61–68. http://dx.doi.org/10.15446/ing.investig.v35n3.50552.

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After the detection of internal defects in materials, the characterization of these plays a decisive role in order to establish the severity of these flaws. Finite difference thermal contrast (FDTC) is a new technique proposed recently for contrast enhancement in sequences of thermal images in order to allow the detection of internal flaws in composite slabs with greater probability of success. Besides FDTC, a criterion was also conceived for the estimation of the depth of the detected defects, which brings good results for shallow and strong contrast defects, but poor estimations for deeper and weaker defects. Considering this problem, a revision of the original criterion is carried out in this paper to define a new and robust criterion for estimating the depth of defects, applied after FDTC en-hancement and flaws detection. Results of the execution of the revised algorithm on a synthetized thermal sequence from an artificial CFRP slab (using ThermoCalc6L software) show a better performance of the estimation task, reducing the average relative error by more than half.

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35

Shimizu, Yuki, Yuki Matsuno, Yuan-Liu Chen, and Wei Gao. "Design and Testing of a Micro Thermal Sensor for Non-Contact Surface Defect Detection." International Journal of Automation Technology 11, no. 5 (August 30, 2017): 781–86. http://dx.doi.org/10.20965/ijat.2017.p0781.

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This paper presents an experimental study on a new concept of a surface defect detection method, in which surface defects will be detected by monitoring a change in heat flow between a micro thermal sensor and a smoothly-finished measuring surface such as magnetic disks, sapphire substrates and so on. In the proposed method, the micro thermal sensor is designed to detect surface defects without any contacts in between them. Since the change in heat flow across the gap is utilized, the method is expected to find out both the convex and concave defects. Searching for the possibility of the non-contact surface defect detection by the micro thermal sensor, in this paper, a simple heat transfer model is established to estimate the change in heat flow due to the change in gap between the measuring surface and the sensor surface. Some basic experiments are also carried out by using prototype micro thermal sensors, each of which is composed of a pair of electrodes and a thin metal film resistor, fabricated on both the silicon and glass substrates.

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Wang, Kangning, Bin Li, and Wenming Wu. "Compressed Air-Driven Continuous-Flow Thermocycled Digital PCR for HBV Diagnosis in Clinical-Level Serum Sample Based on Single Hot Plate." Molecules 25, no. 23 (November 30, 2020): 5646. http://dx.doi.org/10.3390/molecules25235646.

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We report a novel compressed air-driven continuous-flow digital PCR (dPCR) system based on a 3D microfluidic chip and self-developed software system to realize real-time monitoring. The system can ensure the steady transmission of droplets in long tubing without an external power source and generate stable droplets of suitable size for dPCR by two needles and a narrowed Teflon tube. The stable thermal cycle required by dPCR can be achieved by using only one constant temperature heater. In addition, our system has realized the real-time detection of droplet fluorescence in each thermal cycle, which makes up for the drawbacks of the end-point detection method used in traditional continuous-flow dPCR. This continuous-flow digital PCR by the compressed air-driven method can meet the requirements of droplet thermal cycle and diagnosis in a clinical-level serum sample. Comparing the detection results of clinical samples (hepatitis B virus serum) with commercial instruments (CFX Connect; Bio Rad, Hercules, CA, USA), the linear correlation reached 0.9995. Because the system greatly simplified the traditional dPCR process, this system is stable and user-friendly.

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37

TANIAI, Tetsuya, Hiroshi OHBAYASHI, Takuto YAMAGUCHI, Hitoshi ISHIKAWA, Shunsuke YAMADA, and Naoko TOKUGAWA. "Detection of Flow Seoaration on Aerofoil using Thermal Image Analysis." Journal of the Visualization Society of Japan 29-1, no. 2 (2009): 1137. http://dx.doi.org/10.3154/jvs.29.1137.

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Plaçais, B., and Y. Simon. "Thermal detection of flux-flow noise in type-II superconductors." Physical Review B 39, no. 4 (February 1, 1989): 2151–54. http://dx.doi.org/10.1103/physrevb.39.2151.

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39

Mazur-Milecka, Magdalena, Jacek Ruminski, Wojciech Glac, and Natalia Glowacka. "Detection and Model of Thermal Traces Left after Aggressive Behavior of Laboratory Rodents." Applied Sciences 11, no. 14 (July 20, 2021): 6644. http://dx.doi.org/10.3390/app11146644.

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Automation of complex social behavior analysis of experimental animals would allow for faster, more accurate and reliable research results in many biological, pharmacological, and medical fields. However, there are behaviors that are not only difficult to detect for the computer, but also for the human observer. Here, we present an analysis of the method for identifying aggressive behavior in thermal images by detecting traces of saliva left on the animals’ fur after a bite, nape attack, or grooming. We have checked the detection capabilities using simulations of social test conditions inspired by real observations and measurements. Detection of simulated traces different in size and temperature on single original frame revealed the dependence of the parameters of commonly used corner detectors (R score, ranking) on the parameters of the traces. We have also simulated temperature of saliva changes in time and proved that the detection time does not affect the correctness of the approximation of the observed process. Furthermore, tracking the dynamics of temperature changes of these traces allows to conclude about the exact moment of the aggressive action. In conclusion, the proposed algorithm together with thermal imaging provides additional data necessary to automate the analysis of social behavior in rodents.

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40

Liu, Mingqiang, and Mladen Franko. "Influences of Detection Pinhole and Sample Flow on Thermal Lens Detection in Microfluidic Systems." International Journal of Thermophysics 35, no. 12 (August 24, 2014): 2178–86. http://dx.doi.org/10.1007/s10765-014-1714-1.

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41

AHMAD, Akhundzadah Noor, Hirotaka SAITO, Kei ASADA, and Makoto KATO. "Detecting groundwater flow direction from infrared thermal images." Journal of Groundwater Hydrology 51, no. 2 (2009): 113–26. http://dx.doi.org/10.5917/jagh.51.113.

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42

Hui, Weiwei, Hexiang Zhang, Jianlei Wang, Xuanshi Meng, and Huaxing Li. "Heat transfer characteristics of plasma actuation in different boundary-layer flows." Physics of Fluids 34, no. 3 (March 2022): 034110. http://dx.doi.org/10.1063/5.0084420.

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The coupling characteristics of the aerodynamic and thermal effects of a surface dielectric barrier discharge plasma actuator and its transfer characteristics in different boundary-layer flows are studied experimentally. The actuator is attached to the surface of a flat-plate airfoil and driving by an alternative-current signal. Different boundary-layer flows are achieved in the wind tunnel by adjusting the airfoil's angle of attack with a Reynolds number of 2.02 × 105. The spatial temperature-rise distributions and velocity fields induced by plasma actuation in quiescent air show that the influence range of temperature is consistent with that of the induced velocity field. The aerodynamic and thermal effects induced by plasma actuation have strong coupling characteristics. The heat around the actuator is limited within the boundary-layer flows with a 15 m/s incoming flow. The temperature rise outside the boundary layer is close to zero. In the turbulent boundary-layer flow, the temperature is lower than that in the laminar boundary-layer flow as a whole. The maximum temperature-rise difference exceeds 10 °C. In the leading-edge separation-bubble flow, most heat generated by the plasma actuation is restricted inside the separation bubble. The results provide references for the mechanism detection of related plasma icing-control and flow-control research.

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43

Zhou, Wen, Yi Jiang, Jing Zhang, Chunlai Yu, and Hao Zhu. "Research on Test Method of Power Sensor Battery Considering the Influence of Air Flow." Journal of Physics: Conference Series 2025, no. 1 (September 1, 2021): 012101. http://dx.doi.org/10.1088/1742-6596/2025/1/012101.

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Abstract The reliability of sensor is an important index to determine the outdoor operation efficiency of power sensor, and the reliability detection of power sensor is an important means to ensure the reliability of network equipment. Based on the analysis of the thermal characteristics and thermal behavior of the battery, this paper studies the current detection methods of the low-temperature battery of the power sensor, and proposes a reliability test method of the power sensor considering the influence of outdoor airflow. Through multi-physical field simulation and analysis, the key parameters of relevant experiments are obtained, and the key test parameters are given.

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44

Eidelman, A., T. Elperin, N. Kleeorin, A. Markovich, and I. Rogachevskii. "Experimental detection of turbulent thermaldiffusion of aerosols in non-isothermal flows." Nonlinear Processes in Geophysics 13, no. 1 (April 24, 2006): 109–17. http://dx.doi.org/10.5194/npg-13-109-2006.

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Abstract. We studied experimentally a new phenomenon of turbulent thermal diffusion of particles which can cause formation of the large-scale aerosol layers in the vicinity of the atmospheric temperature inversions. This phenomenon was detected experimentally in oscillating grids turbulence in air flow. Three measurement techniques were used to study turbulent thermal diffusion in strongly inhomogeneous temperature fields, namely Particle Image Velocimetry to determine the turbulent velocity field, an image processing technique to determine the spatial distribution of aerosols, and an array of thermocouples for the temperature field. Experiments are presented for both, stably and unstably stratified fluid flows, by using both directions of the imposed mean vertical temperature gradient. We demonstrated that even in strongly inhomogeneous temperature fields particles in turbulent fluid flow accumulate at the regions with minimum of mean temperature of surrounding fluids due to the phenomenon of turbulent thermal diffusion.

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45

Lapušinskij, Aleksandr, Ivan Suzdalev, Nikolaj Goranin, Justinas Janulevičius, Simona Ramanauskaitė, and Gintautas Stankūnavičius. "The Application of Hough Transform and Canny Edge Detector Methods for the Visual Detection of Cumuliform Clouds." Sensors 21, no. 17 (August 29, 2021): 5821. http://dx.doi.org/10.3390/s21175821.

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The increase in flying time of unmanned aerial vehicles (UAV) is a relevant and difficult task for UAV designers. It is especially important in such tasks as monitoring, mapping, or signal retranslation. While the majority of research is concentrated on increasing the battery capacity, it is also important to utilize natural renewable energy sources, such as solar energy, thermals, etc. This article proposed a method for the automatic recognition of cumuliform clouds. Practical application of this method allows diverting of an unmanned aerial vehicle towards the identified cumuliform cloud and improving its probability of flying into a thermal flow, thus increasing the flight time of the UAV, as is performed by glider and paraglider pilots. The proposed method is based on the application of Hough transform and Canny edge detector methods, which have not been used for such a task before. For testing the proposed method a dataset of different clouds was generated and marked by experts. The achieved average accuracy of 87% on the unbalanced dataset demonstrates the practical applicability of the proposed method for detecting thermals related to cumuliform clouds. The article also provides the concept of VilniusTech developed UAV, implementing the proposed method.

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46

Leith, J. R. "Detection of roll transitions in thermal convection." Experiments in Fluids 5, no. 5 (1987): 354. http://dx.doi.org/10.1007/bf00277716.

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47

Zhang Ping, 张萍, 童亚拉 Tong Yala, 欧阳光耀 Ouyang Guangyao, and 白禄峰 Bai Lufeng. "Detecting Thermal Flaw Inner Cylinder Head Based on Infrared Thermograph Technology." Laser & Optoelectronics Progress 47, no. 11 (2010): 111103. http://dx.doi.org/10.3788/lop47.111103.

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48

Dinh, Toan, Hoang-Phuong Phan, Afzaal Qamar, Nam-Trung Nguyen, and Dzung Viet Dao. "Flexible and multifunctional electronics fabricated by a solvent-free and user-friendly method." RSC Advances 6, no. 81 (2016): 77267–74. http://dx.doi.org/10.1039/c6ra14646e.

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Pencil-drawn flexible and multifunctional electronic devices have been proven to show potential for various applications including mass and flow sensors, human-motion detection and wearable thermal therapy.

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49

Hatch, Andrew C., Tathagata Ray, Kelly Lintecum, and Cody Youngbull. "Continuous flow real-time PCR device using multi-channel fluorescence excitation and detection." Lab Chip 14, no. 3 (2014): 562–68. http://dx.doi.org/10.1039/c3lc51236c.

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We have developed a ‘conveyor belt’ analog for real-time quantitative polymerase chain reaction (qPCR) in a continuous flow thermocycler. The device integrates droplet emulsion technology with LED and fiber optic fluorescence excitation in conjunction with a continuous flow thermal cycler to achieve real-time fluorescence detection.

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50

Yamaoka, Satomi, Yui Kataoka, Yuto Kazama, Yusaku Fujii, and Akihide Hibara. "Efficient thermal lens nanoparticle detection in a flow-focusing microfluidic device." Sensors and Actuators B: Chemical 228 (June 2016): 581–86. http://dx.doi.org/10.1016/j.snb.2016.01.072.

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