Combination Of Thermography Research Articles

Impact Damage Detection of a Glass Fabric Composite Using Carbon Fiber Sensors with Regard to Mechanical Loading

Structural Health Monitoring (SHM) of composite structures leads to greater safety during operation and reduces the cost of regular inspections. Impact damage detection is an important SHM task. Since impact damage can significantly reduce the lifetime of composite structures, sensors for impact damage are of great interest. Carbon Fiber Sensors (CFSs) can be used to detect composite damage. CFSs are lightweight and compact, and they can be integrated during the manufacturing process. In our study, CFSs were manufactured from three types of carbon fiber tows and were integrated into different layers of the lay-up in order to investigate the influence on impact damage detection. The effect of mechanical loading and temperature change on the measured electrical resistance was investigated during cyclic flexural tests. It was revealed that, it is possible to distinguish between changes in measured signals due to impact and due mechanical loading. The change in the measured electrical signal caused by temperature can be eliminated. CFSs can be used for impact damage detection of a glass fabric composite. A combination of thermography and CFSs as an active heating element also provides good results in the field of impact damage detection

Do marmosets understand others' conversations? A thermography approach.

What information animals derive from eavesdropping on interactions between conspecifics, and whether they assign value to it, is difficult to assess because overt behavioral reactions are often lacking. An inside perspective of how observers perceive and process such interactions is thus paramount. Here, we investigate what happens in the mind of marmoset monkeys when they hear playbacks of positive or negative third-party vocal interactions, by combining thermography to assess physiological reactions and behavioral preference measures. The physiological reactions show that playbacks were perceived and processed holistically as interactions rather than as the sum of the separate elements. Subsequently, the animals preferred those individuals who had been simulated to engage in positive, cooperative vocal interactions during the playbacks. By using thermography to disentangle the mechanics of marmoset sociality, we thus find that marmosets eavesdrop on and socially evaluate vocal exchanges and use this information to distinguish between cooperative and noncooperative conspecifics.

Photovoltaic plant condition monitoring using thermal images analysis by convolutional neural network-based structure

The size and the complexity of photovoltaic solar power plants are increasing, and it requires an advanced and robust condition monitoring systems for ensuring their reliability. This paper proposes a novel method for faults detection in photovoltaic panels employing a thermographic camera embedded in an unmanned aerial vehicle. The large amount of data generated by these systems must be processed and analyzed. This paper presents a novel approach to identify panels to detect hot spots, and to set their locations. Two novels region-based convolutional neural networks are unified to generate a robust detection structure. The main contribution is the combination of thermography and telemetry data to provide a response of the panel condition monitoring. The data are acquired and then automatically processed, allowing fault detection during the inspection. A detailed description of the methodology is presented, including the different stages to build the neural networks, i.e. the training process, the acquisition and processing of data and the outcomes generation. A thermographic inspection of a real photovoltaic solar plant is done to validate the proposed methodology. The accuracy, the efficiency and the performance of the approach under different real scenarios are evaluated statistically obtaining satisfactory results.

Application of thermography for cerebral perfusion imaging during aneurysm surgery

Abstract The success of aneurysm surgery depends on complete clipping of the aneurysmal sacculation without compromising quality of cerebral perfusion of vessels concerned. An established intraoperative method to visualize cerebral blood flow i n a pparent v essels i s fl uorescence vi deo angiography based on indocyanine green (ICG). However, major disadvantages of indocyanine green video angiography (ICG VA) are the need of a specialized imaging system, potential drug side effects as well as the limited number of repetitions due to long decay time of ICG in blood circulation. In particular the last drawback prevents brain parenchymal perfusion monitoring with ICG VA. The application of time-resolved thermography as a fast, contactless, noninvasive, marker-free and harmless imaging tool became a promising approach for perfusion imaging and thus offers several advantages compared to ICG. Measurements of deep structures in heat traps for identification of i nternal patterns, e ssential f or e .g. s uccess monitoring of aneurysm clipping, are still unsolved challenges of thermography. This work reveals as a proof of concept that the combination of thermography and an intravenous cold saline bolus injection as a contrast agent is capable to detect arterial and parenchymal perfusion located in the surgical cavity during aneurysm surgery in comparison to state-of-the-art ICG VA. The investigations provide evidence that thermography has the capability to perform intraoperative imaging of cerebral perfusion at an advanced stage in surgery for vessels and parenchyma located both cortically and in the surgical cavity.

Whole-field imaging of temperature and hydrodynamics in a gas fluidized bed with liquid injection

This work presents results of experiments on thermal effects and flow dynamics in a flat-bed geometry gas-fluidized bed at atmospheric pressure, with and without liquid injection. Whole-field measurements have been performed using a combination of thermography, particle image velocimetry and digital image analysis. A first series of experiments demonstrates the mixing of two layers of particles at initially different temperature for a sequence of injected gas bubbles. It is shown that the pulse duration strongly affects the solids mixing and that the influence of diffusion on thermal equilibration is limited without convective mixing. Subsequently liquid has been injected into the fluidizing bed, which has been carried out with water, isopentane and hexane. Owing to the use of a combination of infrared and visual cameras, under particular conditions liquid-solid conglomerates can be observed in situ. Under the conditions applied, the flow dynamics are not clearly affected by the liquid injection. The thermal behavior of the bed is not found to be strongly dependent on which of the model liquids is injected, but more on the cooling capacity obtained by evaporating the injected amount of liquid at the selected injection rate, and the mode of operation.

Fibrossarcoma em onça-pintada (Panthera onca): uso da termografia associada à citologia aspirativa como auxílio diagnóstico

Infrared thermography is a safe and non-invasive method of research used to aid the diagnosis of inflammation, infectious diseases and muscle damage, as well as in reproductive control. The images captured by thermography convert infrared radiation emanating from the body in a temperature gradient, represented by a pattern of visible colors. Aspiration cytology, on the other hand, is an easily applicable research tool that offers excellent preliminary results and directs the clinical case towards a diagnosis. A male jaguar (Panthera onca) presenting a tumor in the abdominal region was examined with the aid of a thermal imager and later a fine needle aspiration cytology was performed. These methods disclosed a mesenchymal malignant neoplasm; later histopathological analysis confirmed the diagnosis of fibrosarcoma. The combination of thermography with fine needle aspiration cytology provided excellent results, showing efficiency, speed and convenience as a diagnostic aid.

Study on Liquid Moisture Transport of Knitted Fabrics by Means of Mmt, Thermography and Microtomography Systems

Abstract Liquid moisture transport of textile structures has been studied in order to manage human perspiration well. This article deals with investigation of dynamic moisture transport of knitted fabrics by sophisticated methods, such as moisture management tester (MMT), thermography and microtomography systems. Three groups of knitted fabrics were analysed by the above-mentioned methods. Specifically, the distribution of liquid drops on samples was compared with the results of vertical wicking of tested materials and the parameter of three-dimensional fabric porosity. Both dynamic spreading of liquid drops on the surface of samples (from top and bottom sides simultaneously) and vertical wicking behaviour of textiles were analysed by the combination of thermography and image analysis system. Further, the results from MMT and porosity analysis by microtomography system were investigated to specify the interaction between structure parameters of knitted fabrics and their liquid transport properties which influence total wear comfort.

Leaf structural reddening in smoke tree and its significance

The smoke tree (Cotinus coggygria Scop.) is not only an important ornamental tree that changes the color of its leaves in autumn but also maintains red juvenile leaves on vigorous sprouting shoots. To elucidate the process of leaf reddening in the smoke tree, we examined the structure and function of its leaf venation system, anthocyanin levels, leaf water conservation ability in red juvenile leaves and green mature leaves, leaf temperature, stomata conductance and snap strength of petiole. A combination of thermography, image analyses and photosynthetic measuring technology was used to study the facts of leaf reddening of smoke tree. We found that spatial and temporal heterogeneity in the pattern of leaf reddening in the smoke tree illustrates the interaction between internal metabolism and environmental factors. These results indicate that there are periods that show water and energy imbalances at leaf lamina and that this phenomenon is essential to leaf reddening, especially during periods of leaf expanding and leaf shedding. We consistently observed a relationship between high temperatures and leaf reddening, which indicates the latter is a photoprotective response induced by imbalances in water and energy.

Investigation of the Damage Behavior of Cast Steel 42CrMo4 During Ultrasonic Fatigue by Combination of Thermography and Fractography

The present paper illustrates the application of infrared thermography measurements for the investigation of fatigue behavior of different types of defects in the high‐cycle fatigue range of cast steel 42CrMo4 alloy (1.732). The influence of several defects on the fatigue damage behavior was studied by the combination of fractography and thermography. Different crack initiation times and locations of several defects were detected and evaluated in one specimen. Furthermore, a direct correlation of fractography and thermography was carried out. The presented results demonstrate well that the combination of fractography and thermography can give a significant contribution to the knowledge of crack initiation and propagation modes during ultrasonic fatigue of 42CrMo4 steel.

Thermal waves for NDE of aircraft: comparison of lockin thermography and lockin interferometry

Optically and ultrasonic-excited lockin thermography have been set in contrast with lockin shearography theoretically and experimentally. Investigated criteria are the differences in depth range, defect selectivity and the comparison of thermal and mechanical response using the example of model specimens and real large-scale aircraft components. An approach for the application of data fusion for defect classification through combination of thermography and shearography phase angle images follows. Due to lack of experience with this technique, it is applied to model specimens only instead of large-scale aircraft components. However, the gradient image characteristic of shearography impedes distinct information extraction.

Deformation Data from Thermal Marking

Abstract: A novel experimental technique for strain measurement, named thermal moiré, and based on a combination of thermography and moiré concepts, is presented in this paper. The proposed technique essentially involves the temporary imprinting of a thermal pattern onto the surface of the object of interest as a substitute for conventional gratings, to remove the need for physical printing, etching or bonding. In materials with low diffusivity, the thermal pattern can be observed with an infrared camera and analysed using conventional techniques. Work on the development of suitable laboratory apparatus is described, and preliminary experimental results are presented to illustrate the feasibility of the method.

The value of adding thermographic leg scanning to impedance plethysmography in the detection of deep vein thrombosis

The clinical value of adding thermographic leg scanning to impedance plethysmography was evaluated and compared in 52 patients with clinically suspected deep venous thrombosis. Both tests were performed on the day of referal and phlebograpphy within 72 hours . The sensitivity of thermography was 83%, the specifity 41% and the accuracy 61%. In comparison IPG had a sensitivity of 83%, a specificity of 96% and an accuracy of 90% The combination of thermography and IPG showed a sensitivity of 92%, a specificity of 41% and an accuracy of 65%. It is concluded that the addition of thermography to IPG is of no clinical value.

Deep vein thrombosis after renal transplantation: a prospective analysis of frequency and risk factors.

In a prospective study the frequency of deep vein thrombosis during the first 3 weeks after kidney transplantation has been evaluated using the combination of thermography and strain-gauge plethysmography for objective diagnosis. 83 consecutive patients were included, 33 with juvenile diabetes mellitus. The overall frequency of thrombosis was 24.1%, diabetes mellitus being a significant risk factor. No other risk factors were found. The transplant did not influence the venous outflow from the corresponding leg. Plasminogen activator activity in the iliac vein wall at transplantation did not differ between patients with and without thrombosis.

Thermography in the Diagnosis of Deep Venous Thrombosis

Thermography, clinical examination and 99Tcm-plasmin test were performed in 112 patients and compared with phlebography. The study population consists of consecutive outpatients with symptoms compatible with deep venous thrombosis, who presented during regular clinic hours. Scoring systems were constructed for the clinical and thermographic evaluation. Both thermography and clinical diagnosis were insufficiently sensitive and specific for screening purposes. Plasmin test had a high sensitivity, 95%, but a low specificity. It is possible that a combination of thermography and clinical diagnostic criteria can provide an acceptable screening procedure. Combining thermography with a routine examination by the physician on duty yielded less favourable results.