Rail squats are a form of near surface rolling contact fatigue damage found in rail heads. Currently, the most popular method to detect the rail squats is utilizing ultrasonic techniques to determine their presence an...Rail squats are a form of near surface rolling contact fatigue damage found in rail heads. Currently, the most popular method to detect the rail squats is utilizing ultrasonic techniques to determine their presence and measure their depths. This technique needs to be direct contact between the probe and the rail head, with a coupling fluid in at the interface. Other weaknesses of these ultrasonic techniques include false detections as well as missed detections. Infrared thermography is a relatively new non-destructive inspection technique used for a wide range of applications but is not used for rail squat detection. Lock-in thermography is a non-destructive inspection technique that can be used for the detection of near surface defects. It utilizes an infrared camera to detect the thermal waves and then produces a thermal image, which displays the local thermal wave variation in phase or amplitude. In inhomogeneous materials, the amplitude and phase of the thermal wave carries information related to both the local thermal properties and the nature of the structure being inspected. This comparison is then used to determine the phase angle difference (Δf) between the input and the thermal response of the object. The aim of this paper is to determine whether lock-in thermography can be used to firstly locate squats in rails, and secondly measure their depths. It has demonstrated the feasibility for using such a technique in generating thermal responses that could be adequately utilized for the purpose of defect characterization.展开更多
Musculoskeletal injuries are among the most common causes of disability worldwide,with early detection and appropriate intervention critical to minimizing long-term complications.Infrared thermography(IRT)has emerged ...Musculoskeletal injuries are among the most common causes of disability worldwide,with early detection and appropriate intervention critical to minimizing long-term complications.Infrared thermography(IRT)has emerged as a noninvasive,real-time imaging modality that captures superficial temperature changes reflecting underlying physiological processes such as inflammation and vascular alterations.This review explores the fundamental principles of medical thermography,differentiates between passive and active approaches,and outlines key technological advancements including artificial intelligence integration.The clinical utility of IRT is discussed in various contexts–ranging from acute soft tissue injuries and overuse syndromes to chronic pain and rehabilitation monitoring.Comparative insights with conventional imaging techniques such as ultrasound and magnetic resonance imaging are also presented.While IRT offers functional imaging capabilities with advantages in portability,safety,and speed,its limitations–such as lack of deep-tissue penetration and protocol standardization–remain significant barriers to broader adoption.Future directions include the integration of IRT with other imaging modalities and digital health platforms to enhance musculoskeletal assessment and injury prevention strategies.展开更多
The motivation of this paper is to explore the application of Step-Heating Thermography(SHT)as a technique capable of inspecting new composite rail carbodies using demanding requirements set by the rail manufacturing ...The motivation of this paper is to explore the application of Step-Heating Thermography(SHT)as a technique capable of inspecting new composite rail carbodies using demanding requirements set by the rail manufacturing industry.A large composite sample,with Polytetrafluoroethylene(PTFE)artificial defects,replicating a side-wall section of a new rail carbody,was manufactured and inspected for surface and subsurface defects in this research.The sample,characterized by its large thickness,consists of a monolithic Carbon Fibre Reinforced Polymers(CFRP)component(20mm thickness)and a CFRP-PET foam-CFRP sandwich(40mm total thickness)component fused together.The main challenge of the inspection procedure was to apply reflection mode thermography and detect defects in the entire thickness of the sample that exhibits both low emissivity and thermal insulating properties,especially at the sandwich sections of the sample.The paper explored thermography procedures that would be able to detect large numbers of defects under one single acquisition and would be applied under an automated inspection process leading to the detection of defects only up to 5mm in the CFRP sections of the sample while no defects were able to be detected at the back skin of the sample.展开更多
Civil infrastructure is continuously subject to aging and deterioration due to multiple factors,which lead to a decline in performance and impact structural health.Accumulated damage on structures increases operationa...Civil infrastructure is continuously subject to aging and deterioration due to multiple factors,which lead to a decline in performance and impact structural health.Accumulated damage on structures increases operational costs and poses significant risks to public safety.Effective maintenance,repair,and rehabilitation strategies are needed to ensure civil infrastructure’s overall safety and reliability.Non-Destructive Evaluation(NDE)methods are utilized to assess latent damage and provide decision-makers with real-time information for mitigating hazards.Within the last decade,there has been a significant increase in the research and development of innovative NDE techniques to improve data processing and promote efficient and accurate infrastructure assessment.This paper aims to review one of those methods,namely,Infrared Thermography(IRT),and its applications in civil infrastructure.A comprehensive review is presented by investigating numerous journal articles,research papers,and technical reports describing numerous IRT applications for bridges,buildings,and general civil structures made from different materials.The capability of IRT to identify and pinpoint anomalies,typically in the early stages of degradation,has excellent potential to improve the safety and shore up the dependability of civil infrastructures while reducing expenses tied to maintenance and rehabilitation.Furthermore,the non-invasive nature of IRT is beneficial in mitigating disturbances and downtime that may occur during various inspection procedures.It is highlighted that IRT is a highly versatile and effective tool for infrastructure condition assessment.With further advancement and fine-tuning of the available techniques,it is likely that IRT will continue to gain significant popularity in maintaining and monitoring civil infrastructure.展开更多
Objective:To evaluate the use of infrared thermography technology for objective and quantitative syndrome differentiation and treatment in traditional Chinese medicine(TCM),specifically in patients with Chaihu Guizhi ...Objective:To evaluate the use of infrared thermography technology for objective and quantitative syndrome differentiation and treatment in traditional Chinese medicine(TCM),specifically in patients with Chaihu Guizhi Ganjiang Decoction syndrome.Methods:Data were collected from over 100 patients diagnosed with Chaihu Guizhi Ganjiang Decoction syndrome at Professor Li Leyu’s endocrinology clinic,Zhongshan Hospital of Traditional Chinese Medicine,Guangdong Province,between April 2021 and April 2022.Body surface temperature data were obtained using the MTI-EXPRO-2013-B infrared thermography system.Principal component analysis(PCA)was applied to differentiate temperature distribution characteristics between genders,and a neural network prediction model was constructed for syndrome diagnosis.Results:Infrared thermography effectively captured surface temperature characteristics of patients with Chaihu Guizhi Ganjiang Decoction syndrome.PCA identified one principal component with a variance explanation rate of 73.953%for females and two principal components with a cumulative variance explanation rate of 77.627%for males.The neural network model demonstrated high predictive performance,with an area under the ROC curve of 0.9743 for the training set and 0.9889 for the validation set.Sensitivity was 1,specificity 0.8636,precision 0.8846,accuracy 0.9333,and the F1 score 0.9388.Conclusion:Infrared thermography provides an innovative,objective,and quantitative method for syndrome differentiation and treatment in TCM.It represents a significant advancement in transitioning from traditional empirical approaches to modern,visualized,and precise diagnosis and treatment.This study underscores the potential of integrating advanced technologies in TCM for enhanced clinical application and modernization.展开更多
Fatigue behavior of AZ31B magnesium alloy electron beam welded joint undergoing cyclic loading was investigated by infrared thermography. Temperature evolution throughout a fatigue process was presented and the mechan...Fatigue behavior of AZ31B magnesium alloy electron beam welded joint undergoing cyclic loading was investigated by infrared thermography. Temperature evolution throughout a fatigue process was presented and the mechanism of heat generationwas discussed. Fatigue limit of the welded joint was predicted and the fatigue damage was also assessed based ontheevolution of the temperatureand hotspot zone on the specimen surfaceduring fatigue tests. The presented results show that infrared thermography can not onlyquicklypredict the fatigue behavior of the welded joint, but also qualitatively identify the evolution of fatigue damage in real time. It is found that the predicted fatigue limit agrees well with the conventionalS-Nexperimental results. The evolution of the temperatureand hotspot zone on the specimen surface can be an effectivefatigue damage indicatorfor effectiveevaluationof magnesium alloy electron beam welded joint.展开更多
The method of infrared thermography to predict the temperature of the sulfide ores has a large error. To solve this problem, the temperature of the sulfide ores is measured by thermal infrared imager and recording the...The method of infrared thermography to predict the temperature of the sulfide ores has a large error. To solve this problem, the temperature of the sulfide ores is measured by thermal infrared imager and recording thermometric instrument contrastively. The main factors, including emissivity, distance, angle and dust concentration that affect the temperature measurement precision, are analyzed. The regression equations about the individual factors and comprehensive factors are obtained by analyzing test data. The application of the regression equations improves the precision of the thermal infrared imager. The geometric information lost in traditional infrared thermometry is determined by visualization grid method and interpolation method, the relationship between the infrared imager and geometry information is established. The geometry location can be measured exactly.展开更多
The feasibility of electromagnetically stimulated thermography non-destructive testing(NDT)for the detection of defects in metallic conductive materials has been carried out by finite element analysis.Aluminum plates ...The feasibility of electromagnetically stimulated thermography non-destructive testing(NDT)for the detection of defects in metallic conductive materials has been carried out by finite element analysis.Aluminum plates with defects of different diameters,depths,locations,shapes and orientation with respect to eddy current are numerically investigated.ANSYS software is used to solve the coupled electromagnetic and temperature field equations.The peak temperatures on the top surface of circular defects with different diameters and depths are calculated at varying excitation frequencies.It is demonstrated that the obtained temperature inreases with increase of the defect diameter and decrease of its depth.The dependence of the temperature over the top surface of the defect on its location and orientation is also presented.The results indicate that we can detect the subsurface defect and estimate its depth and location by choosing a suitable coil-specimen configuration.展开更多
During manufacturing and operation, different kinds of defects, e.g., delamination or surface cracks, may be generated in the plasma-facing components (PFCs) of a Tokamak device. To ensure the safety of the PFCs, vari...During manufacturing and operation, different kinds of defects, e.g., delamination or surface cracks, may be generated in the plasma-facing components (PFCs) of a Tokamak device. To ensure the safety of the PFCs, various kinds of nondestructive testing (NDT) techniques are needed for different defect and failure mode. This paper gives a review of the recently developed ultrasonic testing (UT) and laser thermography methods for inspection of the delamination and surface cracks in PFCs. For monoblock W/Cu PFCs of divertor, the bonding quality at both W-Cu and Cu- CuCrZr interfaces was qualified by using UT with a focus probe during manufacturing. A noncontact, coupling-free and flexible ultrasonic scanning testing system with use of an electromagnetic acoustic transducer and a robotic inspection manipulator was introduced then for the in-vessel inspection of delamination defect in first wall (FW). A laser infrared thermography testing method is highlighted for the on-line inspection of delamination defect in FW through the vacuum vessel window of the Tokamak reactor. Finally, a new laser spot thermography method using laser spot array source was described for the online inspection of the surface cracks in FW.展开更多
The fatigue behavior during high cycle fatigue testing and the tensile behavior of 5A06 aluminum alloy considering the anisotropy were studied.Two types of specimens including longitudinal specimen（parallel to the ro...The fatigue behavior during high cycle fatigue testing and the tensile behavior of 5A06 aluminum alloy considering the anisotropy were studied.Two types of specimens including longitudinal specimen（parallel to the rolling direction） and transverse specimen（perpendicular to the rolling direction） were prepared.Infrared thermography was employed to monitor the temperature evolution during the fatigue and tensile tests.The temperature evolution curves in the two directions were contrastively analyzed.It is found that the temperature evolution during fatigue process possesses four stages：initial temperature rise stage,slow temperature decline stage,rapid temperature rise stage,and finial temperature decline stage.The heat generating mechanisms of the four stages are discussed.Obvious differences can be found between the longitudinal specimen and transverse specimen in fatigue strength and fatigue life.The fatigue strength and fatigue life of longitudinal specimen are higher than those of transverse specimen.During the tensile and fatigue testing process,the fracture temperature in the transverse direction are higher than that in the longitudinal direction.The fatigue strength prediction by means of infrared thermography has a good consistency with that by the traditional method.展开更多
In order to capture the mechanism of roadway instability in deep mines, a new approach of Physically Finite Elemental Slab Assemblage (PFESA) is proposed in order to construct a large-scale physical model simulating t...In order to capture the mechanism of roadway instability in deep mines, a new approach of Physically Finite Elemental Slab Assemblage (PFESA) is proposed in order to construct a large-scale physical model simulating the geologically horizontal strata. We carried out physical modeling on the deformation and failure processes of roadways subjected to a plane loading scheme. Our laboratory tests were based on work which incorporated infrared (IR) detection, IR radiation temperature (IRT) statistics, image feature extraction and 2D Fourier transformation, from resulting thermographies. The IRT characterizes the mechanical responses from the roadway after loading with two stages, i.e., IRT evolving at higher levels corresponded to shallow mining (≤500 m) during which the roadway deformed gradually (referred to as the "steady deformation stage"); IRT evolving in a quasi-cyclical manner with multiple peaks corresponded to deep mining (800–2600 m), in which the failure mode for the roadway are dominated by breakage and collapse (called the "unsteady deformation stage"). The IR images and 2D Fourier spectra illustrate detailed information in terms of initiation, nucleation and coalescence of the damage to rock masses and the eventual failure of roadways subject to external loading.展开更多
Numerical simulations are performed to study the aeroelastic responses of an elastically suspended airfoil in transonic buffet flow, by coupling the unsteady Reynolds-averaged Navier- Stokes （RANS） equations and str...Numerical simulations are performed to study the aeroelastic responses of an elastically suspended airfoil in transonic buffet flow, by coupling the unsteady Reynolds-averaged Navier- Stokes （RANS） equations and structural motion equation. The current work focuses on the char- acteristic analysis of the lock-in phenomenon. Great attentions are paid to studying the frequency range of lock-in and the effects of the three parameters, namely the structural natural frequency, mass ratio and structural damping, on lock-in characteristic of the elastic system in detail. It is found that when the structural natural frequency is close to the buffet frequency, the coupling fre- quency of the elastic system is no longer equal to the buffet frequency, but keeps the same value as the structural natural frequency. The frequency lock-in occurs and stays present until the structural nature frequency is near the double buffet frequency. It means that the lock-in presents within a broad range, of which the lower threshold is near the buffet frequency, while the upper threshold is near the double buffet frequency. Moreover, the frequency range of lock-in is affected by mass ratio and structural damping. The lower the mass ratio and structural damping are, the wider the range of lock-in will be. The upper threshold of lock-in grows with the mass ratio and structural damping decreasing, but the lower threshold always keeps the same.展开更多
Manual inspections of infrastructures such as highway bridge, pavement, dam, and multistoried garage ceiling are time consuming, sometimes can be life threatening, and costly. An automated computerized system can redu...Manual inspections of infrastructures such as highway bridge, pavement, dam, and multistoried garage ceiling are time consuming, sometimes can be life threatening, and costly. An automated computerized system can reduce time, faulty inspection, and cost of inspection. In this study, we developed a computer model using deep learning Convolution Neural Network (CNN), which can be used to automatically detect the crack and non-crack type structure. The goal of this research is to allow application of state-of-the-art deep neural network and Unmanned Aerial Vehicle (UAV) technologies for highway bridge girder inspection. As a pilot study of implementing deep learning in Bridge Girder, we study the recognition, length, and location of crack in the structure of the UTC campus old garage concrete ceiling slab. A total of 2086 images of crack and non-crack were taken from UTC Old Library parking garage ceiling using handheld mobile phone and drone. After training the model shows 98% accuracy with crack and non-crack types of structures.展开更多
This paper describes flow visualization techniques employing surface oil flow and liquid crystal thermography suitable for use in impulse wind tunnels.High spatial resolution photographs of oil flow patterns and liqui...This paper describes flow visualization techniques employing surface oil flow and liquid crystal thermography suitable for use in impulse wind tunnels.High spatial resolution photographs of oil flow patterns and liquid crystal thermograms have been obtained within test times ranging from 7 to 500 ms and have been shown to be very useful for revealing the detailed features of 3-D separated flow.The results from oil flow patterns,liquid crystal thermograms,schlieren photographs and heat flux measurements are shown to be in good agreement.展开更多
In this paper, the use of a signal to noise ratio (SNR) is proposed for the quantification of the goodness of some selected processing techniques of thermographic images, such as differentiated absolute contrast, skew...In this paper, the use of a signal to noise ratio (SNR) is proposed for the quantification of the goodness of some selected processing techniques of thermographic images, such as differentiated absolute contrast, skewness and kurtosis based algorithms, pulsed phase transform, principal component analysis and thermographic signal reconstruction. A new hybrid technique is also applied (PhAC—Phase absolute contrast), it combines three different processing techniques: phase absolute contrast, pulsed phase thermography and thermographic signal reconstruction. The quality of the results is established on the basis of the values of the parameter SNR, assessed for the present defects in the analyzed specimen, which enabled to quantify and compare their identification and the quality of the results of the employed technique.展开更多
In this study,the lock-in phenomenon of Tip Clearance Flow(TCF)instabilities and their relationship to blade vibration are investigated numerically on an axial transonic rotor with a large tip clearance.The capabiliti...In this study,the lock-in phenomenon of Tip Clearance Flow(TCF)instabilities and their relationship to blade vibration are investigated numerically on an axial transonic rotor with a large tip clearance.The capabilities of simulating instability flow and lock-in phenomenon are verified on a transonic rotor and a NACA0012 airfoil by comparing with the test data,respectively.The lock-in phenomenon is first numerically confirmed that may occur to TCF instabilities when its frequency is close to the blade vibration frequency.The lock-in region becomes wider with the vibration amplitude increasing,and it is also affected by modal shapes.For the rotor at the simulation conditions in this study,the bending mode results in a wider lock-in region than the torsional mode.In the lock-in region,the phase difference between the Tip Clearance Vortex(TCV)and the blade vibration changes with the flow condition and the frequency ratio of the blade vibration and the TCV instabilities.The frequency of the TCV instabilities reduces with the mass flow decreasing.Therefore,reducing mass flow and increasing frequency ratio have similar effects on the TCV phase,which causes a significant variation on the unsteady pressure amplitude in the blade tip area.Thus,the aerodynamic damping changes significantly with the TCV phase.The aerodynamic damping displays a nonlinear relationship with the vibration amplitude,and it changes from negative to positive with the vibration amplitude increasing at the same frequency ratio.The negative damping is mainly provided by the tip area of the blade.For unlocked conditions,the period of the TCF instabilities fluctuates over time,and it cannot be directly separated by their frequency features.Inter Blade Phase Angle(IBPA)also has an important influence on the feature of the TCV instabilities.The occurrence of frequency lock-in also requires“appropriate”IBPA.For the examined working conditions,the frequency lock-in occurs under 0 ND(Nodal Diameter),but not under 8 ND.However,no matter 0 ND or 8 ND,the phase of TCV always locks onto the IBPA at the examined conditions.展开更多
We have demonstrated a successful computer model utilizing ANSIS software that is verified with a practical model using Infrared (IR) sensors. The simulation model incorporates the three heat transfer coefficients: co...We have demonstrated a successful computer model utilizing ANSIS software that is verified with a practical model using Infrared (IR) sensors. The simulation model incorporates the three heat transfer coefficients: conduction, convection, and radiation. While the conduction component was a major contributor to the simulation model, the other two coefficients have added to the accuracy and precision of the model. Convection heat allows for the influence of blood flow within the study, while the radiation aspect, sensed through IR sensors, links the practical model of the study. This study also compares simulation data with the applied model generated from IR probe sensors. These sensors formed an IR scanner that moved via servo mechanical system, tracking the temperature distribution within and around the thyroid gland. These data were analyzed and processed to produce a thermal image of the thyroid gland. The acquired data were then compared with an Iodine uptake scan for the same patients.展开更多
Autism spectrum disorder(ASD)is a neurodevelopmental disorder affecting social,communicative,and repetitive behavior.The phenotypic heterogeneity of ASD makes timely and accurate diagnosis challenging,requiring highly...Autism spectrum disorder(ASD)is a neurodevelopmental disorder affecting social,communicative,and repetitive behavior.The phenotypic heterogeneity of ASD makes timely and accurate diagnosis challenging,requiring highly trained clinical practitioners.The development of automated approaches to ASD classification,based on integrated psychophysiological measures,may one day help expedite the diagnostic process.This paper provides a novel contribution for classifing ASD using both thermographic and EEG data.The methodology used in this study extracts a variety of feature sets and evaluates the possibility of using several learning models.Mean,standard deviation,and entropy values of the EEG signals and mean temperature values of regions of interest(ROIs)in facial thermographic images were extracted as features.Feature selection is performed to filter less informative features based on correlation.The classification process utilizes Naive Bayes,random forest,logistic regression,and multi-layer perceptron algorithms.The integration of EEG and thermographic features have achieved an accuracy of 94%with both logistic regression and multi-layer perceptron classifiers.The results have shown that the classification accuracies of most of the learning models have increased after integrating facial thermographic data with EEG.展开更多
文摘Rail squats are a form of near surface rolling contact fatigue damage found in rail heads. Currently, the most popular method to detect the rail squats is utilizing ultrasonic techniques to determine their presence and measure their depths. This technique needs to be direct contact between the probe and the rail head, with a coupling fluid in at the interface. Other weaknesses of these ultrasonic techniques include false detections as well as missed detections. Infrared thermography is a relatively new non-destructive inspection technique used for a wide range of applications but is not used for rail squat detection. Lock-in thermography is a non-destructive inspection technique that can be used for the detection of near surface defects. It utilizes an infrared camera to detect the thermal waves and then produces a thermal image, which displays the local thermal wave variation in phase or amplitude. In inhomogeneous materials, the amplitude and phase of the thermal wave carries information related to both the local thermal properties and the nature of the structure being inspected. This comparison is then used to determine the phase angle difference (Δf) between the input and the thermal response of the object. The aim of this paper is to determine whether lock-in thermography can be used to firstly locate squats in rails, and secondly measure their depths. It has demonstrated the feasibility for using such a technique in generating thermal responses that could be adequately utilized for the purpose of defect characterization.
文摘Musculoskeletal injuries are among the most common causes of disability worldwide,with early detection and appropriate intervention critical to minimizing long-term complications.Infrared thermography(IRT)has emerged as a noninvasive,real-time imaging modality that captures superficial temperature changes reflecting underlying physiological processes such as inflammation and vascular alterations.This review explores the fundamental principles of medical thermography,differentiates between passive and active approaches,and outlines key technological advancements including artificial intelligence integration.The clinical utility of IRT is discussed in various contexts–ranging from acute soft tissue injuries and overuse syndromes to chronic pain and rehabilitation monitoring.Comparative insights with conventional imaging techniques such as ultrasound and magnetic resonance imaging are also presented.While IRT offers functional imaging capabilities with advantages in portability,safety,and speed,its limitations–such as lack of deep-tissue penetration and protocol standardization–remain significant barriers to broader adoption.Future directions include the integration of IRT with other imaging modalities and digital health platforms to enhance musculoskeletal assessment and injury prevention strategies.
文摘The motivation of this paper is to explore the application of Step-Heating Thermography(SHT)as a technique capable of inspecting new composite rail carbodies using demanding requirements set by the rail manufacturing industry.A large composite sample,with Polytetrafluoroethylene(PTFE)artificial defects,replicating a side-wall section of a new rail carbody,was manufactured and inspected for surface and subsurface defects in this research.The sample,characterized by its large thickness,consists of a monolithic Carbon Fibre Reinforced Polymers(CFRP)component(20mm thickness)and a CFRP-PET foam-CFRP sandwich(40mm total thickness)component fused together.The main challenge of the inspection procedure was to apply reflection mode thermography and detect defects in the entire thickness of the sample that exhibits both low emissivity and thermal insulating properties,especially at the sandwich sections of the sample.The paper explored thermography procedures that would be able to detect large numbers of defects under one single acquisition and would be applied under an automated inspection process leading to the detection of defects only up to 5mm in the CFRP sections of the sample while no defects were able to be detected at the back skin of the sample.
文摘Civil infrastructure is continuously subject to aging and deterioration due to multiple factors,which lead to a decline in performance and impact structural health.Accumulated damage on structures increases operational costs and poses significant risks to public safety.Effective maintenance,repair,and rehabilitation strategies are needed to ensure civil infrastructure’s overall safety and reliability.Non-Destructive Evaluation(NDE)methods are utilized to assess latent damage and provide decision-makers with real-time information for mitigating hazards.Within the last decade,there has been a significant increase in the research and development of innovative NDE techniques to improve data processing and promote efficient and accurate infrastructure assessment.This paper aims to review one of those methods,namely,Infrared Thermography(IRT),and its applications in civil infrastructure.A comprehensive review is presented by investigating numerous journal articles,research papers,and technical reports describing numerous IRT applications for bridges,buildings,and general civil structures made from different materials.The capability of IRT to identify and pinpoint anomalies,typically in the early stages of degradation,has excellent potential to improve the safety and shore up the dependability of civil infrastructures while reducing expenses tied to maintenance and rehabilitation.Furthermore,the non-invasive nature of IRT is beneficial in mitigating disturbances and downtime that may occur during various inspection procedures.It is highlighted that IRT is a highly versatile and effective tool for infrastructure condition assessment.With further advancement and fine-tuning of the available techniques,it is likely that IRT will continue to gain significant popularity in maintaining and monitoring civil infrastructure.
基金Zhongshan Science and Technology Bureau Project“The Application of Infrared Thermography in the Syndrome Differentiation of Chaihu Guizhi Ganjiang Decoction”(Project No.2021B1066)Zhongshan Science and Technology Bureau Project“Exploring the Diagnostic Approach of the TCM Syndrome Type‘Chaihu Guizhi Ganjiang Decoction’Based on Infrared Thermal Imaging Systems and Digital Modeling Methods of Ancient and Modern Literature”(Project No.2022B1131)。
文摘Objective:To evaluate the use of infrared thermography technology for objective and quantitative syndrome differentiation and treatment in traditional Chinese medicine(TCM),specifically in patients with Chaihu Guizhi Ganjiang Decoction syndrome.Methods:Data were collected from over 100 patients diagnosed with Chaihu Guizhi Ganjiang Decoction syndrome at Professor Li Leyu’s endocrinology clinic,Zhongshan Hospital of Traditional Chinese Medicine,Guangdong Province,between April 2021 and April 2022.Body surface temperature data were obtained using the MTI-EXPRO-2013-B infrared thermography system.Principal component analysis(PCA)was applied to differentiate temperature distribution characteristics between genders,and a neural network prediction model was constructed for syndrome diagnosis.Results:Infrared thermography effectively captured surface temperature characteristics of patients with Chaihu Guizhi Ganjiang Decoction syndrome.PCA identified one principal component with a variance explanation rate of 73.953%for females and two principal components with a cumulative variance explanation rate of 77.627%for males.The neural network model demonstrated high predictive performance,with an area under the ROC curve of 0.9743 for the training set and 0.9889 for the validation set.Sensitivity was 1,specificity 0.8636,precision 0.8846,accuracy 0.9333,and the F1 score 0.9388.Conclusion:Infrared thermography provides an innovative,objective,and quantitative method for syndrome differentiation and treatment in TCM.It represents a significant advancement in transitioning from traditional empirical approaches to modern,visualized,and precise diagnosis and treatment.This study underscores the potential of integrating advanced technologies in TCM for enhanced clinical application and modernization.
基金Project(51305292)supported by the National Natural Science Foundation of ChinaProject(20105429001)supported by the National Aeronautical Science Foundation of China
文摘Fatigue behavior of AZ31B magnesium alloy electron beam welded joint undergoing cyclic loading was investigated by infrared thermography. Temperature evolution throughout a fatigue process was presented and the mechanism of heat generationwas discussed. Fatigue limit of the welded joint was predicted and the fatigue damage was also assessed based ontheevolution of the temperatureand hotspot zone on the specimen surfaceduring fatigue tests. The presented results show that infrared thermography can not onlyquicklypredict the fatigue behavior of the welded joint, but also qualitatively identify the evolution of fatigue damage in real time. It is found that the predicted fatigue limit agrees well with the conventionalS-Nexperimental results. The evolution of the temperatureand hotspot zone on the specimen surface can be an effectivefatigue damage indicatorfor effectiveevaluationof magnesium alloy electron beam welded joint.
基金Project (51074181) supported by the National Natural Science Foundation of ChinaProject (2010ssxt241) supported by Precious Dissertation Innovation Foundation of Central South University, China
文摘The method of infrared thermography to predict the temperature of the sulfide ores has a large error. To solve this problem, the temperature of the sulfide ores is measured by thermal infrared imager and recording thermometric instrument contrastively. The main factors, including emissivity, distance, angle and dust concentration that affect the temperature measurement precision, are analyzed. The regression equations about the individual factors and comprehensive factors are obtained by analyzing test data. The application of the regression equations improves the precision of the thermal infrared imager. The geometric information lost in traditional infrared thermometry is determined by visualization grid method and interpolation method, the relationship between the infrared imager and geometry information is established. The geometry location can be measured exactly.
基金the National Natural Science Foundation of China(No.51075388)the Fundamental Research Funds for the Central Universities (No.2009KJ05)
文摘The feasibility of electromagnetically stimulated thermography non-destructive testing(NDT)for the detection of defects in metallic conductive materials has been carried out by finite element analysis.Aluminum plates with defects of different diameters,depths,locations,shapes and orientation with respect to eddy current are numerically investigated.ANSYS software is used to solve the coupled electromagnetic and temperature field equations.The peak temperatures on the top surface of circular defects with different diameters and depths are calculated at varying excitation frequencies.It is demonstrated that the obtained temperature inreases with increase of the defect diameter and decrease of its depth.The dependence of the temperature over the top surface of the defect on its location and orientation is also presented.The results indicate that we can detect the subsurface defect and estimate its depth and location by choosing a suitable coil-specimen configuration.
基金the National Magnetic Confinement Fusion Program of China(Grant 2013GB113005)the National Natural Science Foundation of China(Grants51577139 and 11502192)for funding
文摘During manufacturing and operation, different kinds of defects, e.g., delamination or surface cracks, may be generated in the plasma-facing components (PFCs) of a Tokamak device. To ensure the safety of the PFCs, various kinds of nondestructive testing (NDT) techniques are needed for different defect and failure mode. This paper gives a review of the recently developed ultrasonic testing (UT) and laser thermography methods for inspection of the delamination and surface cracks in PFCs. For monoblock W/Cu PFCs of divertor, the bonding quality at both W-Cu and Cu- CuCrZr interfaces was qualified by using UT with a focus probe during manufacturing. A noncontact, coupling-free and flexible ultrasonic scanning testing system with use of an electromagnetic acoustic transducer and a robotic inspection manipulator was introduced then for the in-vessel inspection of delamination defect in first wall (FW). A laser infrared thermography testing method is highlighted for the on-line inspection of delamination defect in FW through the vacuum vessel window of the Tokamak reactor. Finally, a new laser spot thermography method using laser spot array source was described for the online inspection of the surface cracks in FW.
基金Funded by the National Natural Science Foundation of China(Nos.51175364,51505322)Natural Science Foundation of Shanxi Province of China(No.2013011014-3)
文摘The fatigue behavior during high cycle fatigue testing and the tensile behavior of 5A06 aluminum alloy considering the anisotropy were studied.Two types of specimens including longitudinal specimen（parallel to the rolling direction） and transverse specimen（perpendicular to the rolling direction） were prepared.Infrared thermography was employed to monitor the temperature evolution during the fatigue and tensile tests.The temperature evolution curves in the two directions were contrastively analyzed.It is found that the temperature evolution during fatigue process possesses four stages：initial temperature rise stage,slow temperature decline stage,rapid temperature rise stage,and finial temperature decline stage.The heat generating mechanisms of the four stages are discussed.Obvious differences can be found between the longitudinal specimen and transverse specimen in fatigue strength and fatigue life.The fatigue strength and fatigue life of longitudinal specimen are higher than those of transverse specimen.During the tensile and fatigue testing process,the fracture temperature in the transverse direction are higher than that in the longitudinal direction.The fatigue strength prediction by means of infrared thermography has a good consistency with that by the traditional method.
基金Projects 2006CB202200 supported by the Special Funds for the Major State Basic Research ProjectIRT0656 by the Innovative Team Development Project of the State Educational Ministry of China
文摘In order to capture the mechanism of roadway instability in deep mines, a new approach of Physically Finite Elemental Slab Assemblage (PFESA) is proposed in order to construct a large-scale physical model simulating the geologically horizontal strata. We carried out physical modeling on the deformation and failure processes of roadways subjected to a plane loading scheme. Our laboratory tests were based on work which incorporated infrared (IR) detection, IR radiation temperature (IRT) statistics, image feature extraction and 2D Fourier transformation, from resulting thermographies. The IRT characterizes the mechanical responses from the roadway after loading with two stages, i.e., IRT evolving at higher levels corresponded to shallow mining (≤500 m) during which the roadway deformed gradually (referred to as the "steady deformation stage"); IRT evolving in a quasi-cyclical manner with multiple peaks corresponded to deep mining (800–2600 m), in which the failure mode for the roadway are dominated by breakage and collapse (called the "unsteady deformation stage"). The IR images and 2D Fourier spectra illustrate detailed information in terms of initiation, nucleation and coalescence of the damage to rock masses and the eventual failure of roadways subject to external loading.
基金supported by the project of the National Natural Science Foundation of China(No.11272262)
文摘Numerical simulations are performed to study the aeroelastic responses of an elastically suspended airfoil in transonic buffet flow, by coupling the unsteady Reynolds-averaged Navier- Stokes （RANS） equations and structural motion equation. The current work focuses on the char- acteristic analysis of the lock-in phenomenon. Great attentions are paid to studying the frequency range of lock-in and the effects of the three parameters, namely the structural natural frequency, mass ratio and structural damping, on lock-in characteristic of the elastic system in detail. It is found that when the structural natural frequency is close to the buffet frequency, the coupling fre- quency of the elastic system is no longer equal to the buffet frequency, but keeps the same value as the structural natural frequency. The frequency lock-in occurs and stays present until the structural nature frequency is near the double buffet frequency. It means that the lock-in presents within a broad range, of which the lower threshold is near the buffet frequency, while the upper threshold is near the double buffet frequency. Moreover, the frequency range of lock-in is affected by mass ratio and structural damping. The lower the mass ratio and structural damping are, the wider the range of lock-in will be. The upper threshold of lock-in grows with the mass ratio and structural damping decreasing, but the lower threshold always keeps the same.
文摘Manual inspections of infrastructures such as highway bridge, pavement, dam, and multistoried garage ceiling are time consuming, sometimes can be life threatening, and costly. An automated computerized system can reduce time, faulty inspection, and cost of inspection. In this study, we developed a computer model using deep learning Convolution Neural Network (CNN), which can be used to automatically detect the crack and non-crack type structure. The goal of this research is to allow application of state-of-the-art deep neural network and Unmanned Aerial Vehicle (UAV) technologies for highway bridge girder inspection. As a pilot study of implementing deep learning in Bridge Girder, we study the recognition, length, and location of crack in the structure of the UTC campus old garage concrete ceiling slab. A total of 2086 images of crack and non-crack were taken from UTC Old Library parking garage ceiling using handheld mobile phone and drone. After training the model shows 98% accuracy with crack and non-crack types of structures.
文摘This paper describes flow visualization techniques employing surface oil flow and liquid crystal thermography suitable for use in impulse wind tunnels.High spatial resolution photographs of oil flow patterns and liquid crystal thermograms have been obtained within test times ranging from 7 to 500 ms and have been shown to be very useful for revealing the detailed features of 3-D separated flow.The results from oil flow patterns,liquid crystal thermograms,schlieren photographs and heat flux measurements are shown to be in good agreement.
文摘In this paper, the use of a signal to noise ratio (SNR) is proposed for the quantification of the goodness of some selected processing techniques of thermographic images, such as differentiated absolute contrast, skewness and kurtosis based algorithms, pulsed phase transform, principal component analysis and thermographic signal reconstruction. A new hybrid technique is also applied (PhAC—Phase absolute contrast), it combines three different processing techniques: phase absolute contrast, pulsed phase thermography and thermographic signal reconstruction. The quality of the results is established on the basis of the values of the parameter SNR, assessed for the present defects in the analyzed specimen, which enabled to quantify and compare their identification and the quality of the results of the employed technique.
基金supported by the National Natural Science Foundation of China(No.51475022)。
文摘In this study,the lock-in phenomenon of Tip Clearance Flow(TCF)instabilities and their relationship to blade vibration are investigated numerically on an axial transonic rotor with a large tip clearance.The capabilities of simulating instability flow and lock-in phenomenon are verified on a transonic rotor and a NACA0012 airfoil by comparing with the test data,respectively.The lock-in phenomenon is first numerically confirmed that may occur to TCF instabilities when its frequency is close to the blade vibration frequency.The lock-in region becomes wider with the vibration amplitude increasing,and it is also affected by modal shapes.For the rotor at the simulation conditions in this study,the bending mode results in a wider lock-in region than the torsional mode.In the lock-in region,the phase difference between the Tip Clearance Vortex(TCV)and the blade vibration changes with the flow condition and the frequency ratio of the blade vibration and the TCV instabilities.The frequency of the TCV instabilities reduces with the mass flow decreasing.Therefore,reducing mass flow and increasing frequency ratio have similar effects on the TCV phase,which causes a significant variation on the unsteady pressure amplitude in the blade tip area.Thus,the aerodynamic damping changes significantly with the TCV phase.The aerodynamic damping displays a nonlinear relationship with the vibration amplitude,and it changes from negative to positive with the vibration amplitude increasing at the same frequency ratio.The negative damping is mainly provided by the tip area of the blade.For unlocked conditions,the period of the TCF instabilities fluctuates over time,and it cannot be directly separated by their frequency features.Inter Blade Phase Angle(IBPA)also has an important influence on the feature of the TCV instabilities.The occurrence of frequency lock-in also requires“appropriate”IBPA.For the examined working conditions,the frequency lock-in occurs under 0 ND(Nodal Diameter),but not under 8 ND.However,no matter 0 ND or 8 ND,the phase of TCV always locks onto the IBPA at the examined conditions.
文摘We have demonstrated a successful computer model utilizing ANSIS software that is verified with a practical model using Infrared (IR) sensors. The simulation model incorporates the three heat transfer coefficients: conduction, convection, and radiation. While the conduction component was a major contributor to the simulation model, the other two coefficients have added to the accuracy and precision of the model. Convection heat allows for the influence of blood flow within the study, while the radiation aspect, sensed through IR sensors, links the practical model of the study. This study also compares simulation data with the applied model generated from IR probe sensors. These sensors formed an IR scanner that moved via servo mechanical system, tracking the temperature distribution within and around the thyroid gland. These data were analyzed and processed to produce a thermal image of the thyroid gland. The acquired data were then compared with an Iodine uptake scan for the same patients.
基金This work was supported by Old Dominion University,Norfolk,Virginia and University of Moratuwa,Sri Lanka.
文摘Autism spectrum disorder(ASD)is a neurodevelopmental disorder affecting social,communicative,and repetitive behavior.The phenotypic heterogeneity of ASD makes timely and accurate diagnosis challenging,requiring highly trained clinical practitioners.The development of automated approaches to ASD classification,based on integrated psychophysiological measures,may one day help expedite the diagnostic process.This paper provides a novel contribution for classifing ASD using both thermographic and EEG data.The methodology used in this study extracts a variety of feature sets and evaluates the possibility of using several learning models.Mean,standard deviation,and entropy values of the EEG signals and mean temperature values of regions of interest(ROIs)in facial thermographic images were extracted as features.Feature selection is performed to filter less informative features based on correlation.The classification process utilizes Naive Bayes,random forest,logistic regression,and multi-layer perceptron algorithms.The integration of EEG and thermographic features have achieved an accuracy of 94%with both logistic regression and multi-layer perceptron classifiers.The results have shown that the classification accuracies of most of the learning models have increased after integrating facial thermographic data with EEG.
