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Dissertations / Theses on the topic 'Thermographic'

Author: Grafiati
Published: 4 June 2021
Last updated: 15 February 2022

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1

Ranson, Robert Marcus. "Investigation into thermographic phosphors." Thesis, Nottingham Trent University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297737.

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2

Ratsakou, Almpion. "Multi-physical modeling of thermographic inspection methods and fast imaging Fast models dedicated to simulation of eddy current thermography Fast simulation approach dedicated to infrared thermographic inspection of delaminated planar pieces Model based characterisation of delamination by means of thermographic inspection." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS002.

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L’inspection thermographique est une technique populaire de contrôle non destructif qui fournit des images de distributions de température sur de grandes étendues aux surfaces des pièces testées. Détecter les délaminations entre couches métalliques est le sujet ici. La simulation de ces inspections contribue en effet à compléter les études expérimentales, à évaluer les performances en termes de détection, et à être support d'algorithmes basés sur modèles. On se focalise sur un modèle semi-analytique basé sur un développement tronqué en fonctions propres par région. Le problème est résolu dans le domaine de Laplace en temps, et la distribution de température approximée par un développement sur une base produit tensoriel. Les sources considérées sont des lampes flash, mais aussi des sources courants de Foucault (conduisant à un couplage électromagnétisme et chaleur). La description des délaminages sous forme de minces couches d'air se révèle équivalente à l'introduction d'une résistance superficielle au flux de chaleur permettant le traitement via l'approche modale sans discrétisation supplémentaire. Des calculs complémentaires par des codes commercial (méthode des éléments finis) et interne (technique d'intégration finie) confirment l'exactitude. Puis une grande attention est donnée à l'imagerie et la détection. Une procédure en deux étapes est conçue : débruitage des signaux bruts et détection de tout éventuel défaut en utilisant une reconstruction de signal thermographique conduisant à une haute résolution spatiale et temporelle dans le plan transverse, complété par une détection de frontière, puis optimisation itérative, les résultats de la première étape étant utilisées pour la régularisation d'un schéma moindres carrés afin de caractériser épaisseurs et profondeurs. Tout ce qui précède est illustré par de nombreuses simulations numériques dans des conditions proches de l'application
Thermographic inspection is a popular nondestructive testing (NdT) technique that provides images of temperature distribution over large areas at surfaces of tested workpieces. Detecting delaminations between metallic layers is the matter here. Simulation of these inspections indeed helps to complement experimental studies, evaluate performance in terms of detection and support model-based algorithms. A semi-analytical model based on a truncated region eigenfunction expansion for simulation of thermographic inspection is focused onto. The problem is solved in the Laplace domain w.r.t time, and the temperature distribution approximated by expanding it on a tensor product basis. Considered sources are lamps providing thermal excitation but may also be eddy current sources (leading to a coupled electromagnetic and heat problem). The description of the delaminations as thin air gaps between the workpiece layers proves to be equivalent with introduction of a surface resistance to the heat flow, enabling treatment via the applied modal approach without additional discretisation. Complementary computations by industry (Finite Element Method) and in-house (Finite Integration Technique) codes confirm the accuracy of the developments. Then, much attention is put on imaging and detection. A two-step procedure is devised, first denoising of raw signals and detection of any possible defect using a thermographic signal reconstruction leading to high spatial and temporal resolution in the transverse plane, completed by proper edge detection, second an iterative optimization being employed, with results of the first step used for regularization of a least-square scheme to characterize thicknesses and depths. All the above is illustrated by comprehensive numerical simulations in conditions close to practice
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3

Alvandipour, Mehrdad. "Thermographic Image Analysis with Gabor Filters." Thesis, Southern Illinois University at Edwardsville, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10616514.

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We use thermography and pattern classification techniques to classify three different pathologies in veterinary images. The Long Island Veterinary Specialists (LIVS) have provided thermographic images of both normal and diseased animals. The temperature data is linearly remapped to 256 gray levels using the temperature range of 19 to 40 degrees C.The three pathologies are ACL rupture disease, bone cancer, and feline hyperthyroid. The diagnosis of these diseases usually involves radiology and laboratory tests while the method that we propose uses thermographic images and image analysis techniques and is intended for use as a prescreening tool. First, Gabor filters are used to filter the images in each category of pathologies and then various features are extracted and used for classification into normal and abnormal classes. Gabor filters are linear filters that can be characterized by the two parameters, wavelength λ and orientation &thetas;. With two different wavelength and five different orientations, a total of ten different filters were studied. Different combinations of camera views, filters, feature vectors, normalization methods, and classification methods, produce different tests that were examined and the sensitivity, specificity and success rate for each test were produced. Using the Gabor features alone, sensitivity, specificity, and overall success rates of 85% for each of the pathologies was achieved.

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4

Höglund, Kristofer. "Non-destructive Testing Using Thermographic Image Processing." Thesis, Linköpings universitet, Datorseende, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-89862.

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In certain industries, quality testing is crucial, to make sure that the components being manufactured do not contain any defects. One method to detect these defects is to heat the specimen being inspected and then to study the cooling process using infrared thermography. The explorations of non-destructive testing using thermography is at an early stage and therefore the purpose of this thesis is to analyse some of the existing techniques and to propose improvements. A test specimen containing several different defects was designed specifically for this thesis. A flash lamp was used to heat the specimen and a high-speed infrared camera was used to study both the spatial and temporal features of the cooling process. An algorithm was implemented to detect anomalies and different parameter settings were evaluated. The results show that the proposed method is successful at finding the searched for defects, and also outperforms one of the old methods.
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5

Kaltmann, Deena, and s8907403@student rmit edu au. "Quantitative Line-Scan Thermographic Evaluation of Composite Structures." RMIT University. Aerospace, Mechanical & Manufacturing Engineering, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20091019.101029.

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This MEng (Master of Engineering) research thesis evaluates the capabilities and limitations of line-scan thermography for the non-destructive evaluation of composite structures containing hidden defects. In simple terms, line-scan thermography is a state-of-the-art technique in which a focused line of thermal energy is transmitted into a material. Line-scan thermography has great potential for the rapid and low cost non-destructive inspection of composite structures for aircraft, automobiles and ships. In this project, theoretical research exploring the heat transfer physics was undertaken in conjunction with experimental studies to develop an optimum inspection regime for line-scan thermography. The capability of line-scan thermography to detect impact damage in carbon/epoxy laminates was experimentally investigated in Chapter 3. From the impact side, in all materials, line-scan thermography overestimated the size of the impact damage whereas flash thermography underestimated the size. There was a close relationship between the ultrasonic profile and the line-scan thermographic thermal response curve. New experimental data has been produced and analysed for the ability of line-scan thermography to determine the defect as well as the defect size. It was found that line-scan thermography was able to distinguish back drilled holes, but it was not possible to determine accurate defect sizing due to the depth of the holes from the inspected surface and the limitations associated with the line-scan thermographic apparatus itself. There was excellent correlation between the C-scan ultrasonics intensity curves and the line-scan thermographs as well as excellent correlation with the theoretical results. The relationship between line-scan thermography and foreign body objects were experimentally investigated for carbon/epoxy composites. A major limitation found with line-scan thermography is its limited depth penetration, which is highlighted in the foreign object study using 6 mm and 13 mm diameter Teflon® discs and 13 mm Teflon® strips embedded in carbon/epoxy laminates. Depth penetration allowed only 2 mm resolution for the 13 mm diameter discs and 1.5 mm resolution for the 6 mm discs in a composite panel. The results of the investigation of stainless steel shim objects in carbon/epoxy laminates reveal that line-scan thermography is capable of determining their presence and size close to the surface. There was also excellent correlation between the ultrasonic response curve and the line-scan thermographic intensity curve. The results of the investigation of thermoplastic film foreign body objects in carbon/epoxy laminates show that at present line-scan thermography does not have the capability to determin e such defects. Experimental results show that line-scan thermography is capable of detecting large voids, back drilled holes, some foreign body objects, and impact damage. However, the ability of line-scan thermography to measure the defect dimensions is dependent on the size and type of damage, the distance from the line source, the depth of the defect, and the type of composite material.
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6

Qudairat, E. "Thermographic evaluation of nerve injury following facial fracture." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.479394.

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7

Biagioni, Paul A. "Thermographic assessment of herpes labialis infection in humans." Thesis, Queen's University Belfast, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394882.

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8

COSTA, HUMBERTO SILVINO ALVES DA. "CALIBRATION OF A THERMOGRAPHIC CAMERA FOR PRODUCTION PLANNING." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2007. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=11021@1.

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INSTITUTO NACIONAL DE METROLOGIA, QUALIDADE E TECNOLOGIA
LIGHT
O aumento da temperatura de equipamentos de produção de energia elétrica é um indicativo de seu mau funcionamento ou da necessidade de uma manutenção preventiva antes que limites críticos sejam alcançados. Uma técnica utilizada para o diagnóstico é a interpretação do sinal infravermelho captado por uma câmera que fornece uma imagem do campo visual em questão, normalmente conhecida por termovisor. Neste trabalho foi desenvolvida uma metodologia para interpretar o seu sinal tendo em vista o planejamento de manutenção. Inicialmente, foi projetado um dispositivo para calibração de um termovisor na PUC-Rio. Ele consta de um bloco cilíndrico de latão, imerso em um banho de temperatura controlada. A seguir, o termovisor foi calibrado no corpo negro do INMETRO. Através da comparação entre os valores medidos pelo termovisor na PUC-Rio e no INMETRO, a emissividade da superfície pode ser determinada, e ajustada no instrumento para medição de temperatura com superfícies semelhantes. Com o termovisor calibrado, foi feita uma análise do impacto da incerteza de medição de temperatura sobre os procedimentos atualmente empregados pela concessionária de energia elétrica, LIGHT ENERGIA S.A., de modo a otimizar os procedimentos de manutenção de seus equipamentos.
The operating temperature increase of electric energy production equipments is a sign of poor performance or the need of maintenance before critical limits be attained. As a diagnostic tool, the interpretation of the infrared signal, as received by a camera that registers the image of a target, is often used and referred as a thermographic camera. In this work, a methodology was developed to interpret the infrared signal from a camera, aiming a maintenance planning. Initially, a device was designed to calibrate the thermographic camera at PUC-Rio. It consists of a cylindrical brass block, placed inside a controlled temperature bath, having its upper surface painted black and placed about 3 mm above the liquid surface of the bath. Holes were drilled radially, slightly bellow the block upper surface, so that its temperature could be measured by inserted thermocouples. Next, the instrument was calibrated with a black body at INMETRO. The surface emissivity was calculated as a result of the comparison between the calibration results in PUC-Rio and INMETRO. After calibration, the impact of the uncertainty of several parameters in temperature measurement was calculated, following the procedures that are presently adopted by the electric energy utility company LIGHT ENERGIA S.A., so that to optimize the maintenance procedure of equipments.
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9

Watkins, Michael L. "The thermographic nondestructive evaluation of iron aluminide green sheet." W&M ScholarWorks, 1999. https://scholarworks.wm.edu/etd/1539623953.

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The recent development of manufacturing techniques for the fabrication of thin iron aluminide sheet requires advanced quantitative methods for on-line inspection. An understanding of the mechanisms responsible for flaws and the development of appropriate flaw detection methods are key elements in an effective quality management system. The first step in the fabrication of thin FeAl alloy sheet is the formation of a green sheet by cold rolling FeAl powder mixed with organic binding agents. The green sheet composite has a bulk density, which is typically less than about 3.6 g/cc. The finished sheet, with a density of about 6.1 g/cc, is obtained using a series of process steps involving binder elimination, densification, sintering, and annealing. Non-uniformities within the green sheet are the major contributor to material failure in subsequent sheet processing and the production of non-conforming finished sheet. The production environment and physical characteristics of the composite provide for unique challenges in developing a rapid nondestructive inspection capability. The method must be non-contact due to the fragile nature of the composite. Limited access to the material also demands a one-sided inspection technique. An active thermographic method providing for 100% on-line inspection within an industrial, process has been developed. This approach is cost competitive with alternative technologies, such as x-ray imaging systems, and provides the required sensitivity to the variations in material composition. The mechanism of flaw formation and the transformation of green sheet flaws into defects that appear in intermediate and finished sheet products are described. A mathematical model which describes the green sheet heat transfer propagation, in the context of the inspection technique and the compact heterogeneity, is also presented. The potential for feedback within the production process is also discussed.
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10

Emmanuel, Jovine. "A high-throughput thermographic screen for model heterogeneous catalysts." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/374675/.

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Despite the fact that it is now accepted that the particle size and the support in heterogeneous catalysts strongly influences the activity and selectivity of the catalysts, it has been a challenge to measure such effects systematically, especially on model systems. A high-throughput (paral-lel) thermographic screening methodology is described here, which allows such measurements to be made. A screening chip was designed and fabricated in order to produce multiple fields of low stress silicon nitride membranes that exhibit low thermal conductivity and heat capacity. The heat generated on model, supported catalysts in an exothermic reaction deposited on the membranes could then be monitored using a thermal (infra-red) imaging camera. The tempera-ture of the catalyst under steady state reaction conditions was used as a measure of mass or spe-cific catalytic activity. The effectiveness of the screening method to determine catalytic activity was demonstrated for titania supported platinum and gold model catalysts by studying the CO oxidation reaction. For both supported metals we observe strong particle size effects in the ac-tivity. Platinum nanoparticles in the size range of ca. 1 to 8 nm and gold nanoparticles between ca. 1 to 6 nm in size were deposited on an amorphous titania support, as determined from transmission electron microscope image analysis. The reaction of CO and O2 on these model catalysts was measured using the thermographic screening method. The model, supported catalysts were also characterised by TEM and XPS both before and after reaction. The reaction over titania sup-ported platinum was investigated in the temperature range of 80 oC to 240 oC and pressure range 0.072 mbar to 2.4 mbar. The turnover frequency (TOF) and specific mass activity of Pt for CO oxidation increased monotonically with decreasing particle size by a factor of 17. XPS showed that there was no change in the particle size distribution during the reactions. While there is no apparent consensus in the literature concerning a particle size effect for this system, this result is in good agreement with recent findings on high area supported catalysts, finding a seven-fold increase in activity between 10 nm and 1nm particle sizes. The CO oxidation on titania supported gold nanoparticles was investigated at 80 oC and 170 oC and pressure ranging between 0.06 mbar and 1.5 mbar. The TOF and specific mass activity in-creased monotonically with decreasing particle size by a factor of 19. XPS again showed that there was no significant change in the particle size distribution during the reactions. While there is no apparent consensus in the literature concerning the activity trend with particle size for this system, this result is consistent with most data published in the literature. The absolute activities measured at low temperature (ca. 80 oC) and pressure (0.11 mbar) in this study for Au/TiO2 nanoparticle catalyst are higher than Pt/TiO2 nanoparticles over the ranges of particle sizes investigated.
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11

Berndtsson, Therese. "Thermographic Measurements of Hot Materials Using a Low- to High-speed RGB-camera : Prospect of RGB-cameras Within the Field of Thermographic Measurements." Thesis, Luleå tekniska universitet, Rymdteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-74655.

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Monitoring the thermal behavior of material while heated or cooled is of great importance in order to understand the structural behavior of materials. This thesis aims to investigate the prospects for imaging hot materials using an RGB-camera. The main motivation of using an RGB-camera is the very simple set-up and, in comparison to thermal IR-cameras, low price. A method and code enabling thermographic measurements in the temperature range of 800°C up to 1500°C has been produced. Calibration of the RGB-camera was made, the accuracy was predicted to be poor within the temperature range of 1000°C up to about 1200°C. The poor accuracy of the calibration within this range has its source in the non-linear (and irregular) response of the CMOS sensor prohibiting a valid exposure time function to be accurately determined. The calibration is thus performed with different settings (i.e different exposure times and aperture settings) but without any correction for the setting change. The validation experiments were performed in (or very close to) the temperatures where the temperature error was predicted to be the largest. An under-estimation of approximately 30-50°C in the temperature range between 950°C and 1015°C could be seen corresponding to an absolute error of about 3-5% in this temperature range. The accuracy is however thought to increase with the temperature above a temperature of approximately 1250°C . It is possible to perform a temperature transform of target images with temperatures above 1500°C since the Look-up-table produced for the temperature transform extends to about 3000°C . However, the accuracy is unknown since no calibration or validation experiments within these ranges were performed. The result of the calibration and experiments along with the theoretical assessment within the thesis gave background to the discussion of optimal imaging system for thermographic measurements. In order to receive more accurate temperature measurements, a CCD-sensor is to prefer since producing more uniform images with a more linear and predictable response. This would most likely enable the implementation of the camera setting influence. To receive better color accuracy but mainly to prevent channel overlap a system using three sensors instead of one (as for the current imaging system) is to prefer. This would result in larger freedom of channel choice and thus, the temperature transform can somewhat be customized for the specific measured temperature ranges. A brief discussion concerning the overall choice of camera was also brought up. Since the temperature range is large and the red, green and blue channels are sensitive to temperature changes the demands on the sensor dynamic range will be high in order to receive a linear response, or even a fully predictable response, across the whole temperature range. A suggested option to the RGB-camera, still offering the very simple set up, is a dual-wavelength camera in the near (or medium wavelength) infrared range.
Kartläggning av materialförändringar vid uppvärmning eller nedkylning är av stor betydelse för förståelsen för ett materials strukturella beteende. Denna masteruppsatts syftar till att utforska utsikterna för termisk avbildning av varma material med en RGB-kamera. I detta inkluderas kalibrering av kamera, validerings experiment och teoretiska efterforskningar. Det huvudsakliga motivet för användning av en RGB-kamera är den enkla uppställningen (endast en kamera där de olika färg-lagren är alignerade) och det, i jämförelse med många IR-kameror, låga priset. En metod och en kod som möjliggör termografiska mätningar (både video och stillbild) inom temperaturområdet 800°C till 1500°C har tagits fram där kalibrering av kameran är inkluderat. Efter utförd kalibrering förutspåddes att noggrannheten av mätningarna mest troligt skulle vara bristfälliga i området 1000°C upp till cirka 1200°C.  Denna bristfälliga noggrannheten har sin grund i den icke-linjära (och i vissa fall oregelbundna) sensorresponsen vilket, i huvudsak, försvårade bestämning av exponeringstidens signalinflytande. Med anledning av detta gjordes en kalibrering med fixa inställningar, det vill säga; fixa exponeringstider och bländarinställningar för mätningar inom specifika temperaturområden, men utan korrigering vid förändring av kamerainställningar. Valideringsexperimenten som utfördes var i (eller mycket nära) det temperaturområde där de största temperaturavvikelserna förutspåddes vara.  Utförd validering av metod för temperaturavbildning visade att mätningen med RGB-kameran underskattade temperaturerna med cirka 30-50°C i temperaturområdet mellan 975-1015° motsvarar ett absolut fel på cirka 3-5% inom detta temperaturområde. Det är dock troligt att noggrannheten av mätningarna ökar då temperaturerna av det avbildade objektet är större än 1250°C då man i kalibreringsprocessen kunde se mindre avvikelser i detta område.  Med producerad look-up table (skapad i kalibreringsprocessen) är det möjligt att utföra temperaturtransformationer för avbildningar av objekt som har temperaturer över 1500°C, dock med okända osäkerheter då varken kalibrerings- eller valideringsexperiment har utförts för så pass höga temperaturer.  Resultatet av kalibreringen och experimenten, tillsammans med en teoretisk utredning av begränsningar och möjliga förbättringar vid termografiska mätningar, lade grunden till diskussion gällande optimalt bildsystem. Rekommendationer för att i framtiden utföra mer exakta termografiska mätningar med en RGB-kamera togs fram där en 3-CCD kamera föreslogs för att förbättra mätresultaten.  En CCD sensor är att föredra framför en CMOS sensor då de icke-verkliga pixel-avvikelserna inte är lika kritiska för en CCD-sensor som för en CMOS-sensor. CCD-sensorn är dessutom i många aspekter mer tillförlitlig vid vetenskapliga mätningar och har oftast mer linjär och förutsägbar respons vilket mest troligt skulle möjliggöra inkludering av exponeringstidens signalinflytande.  En kort diskussion gällande val av kanaler (våglängdsområden) som kan användas vid temperaturmätningar tas även upp i avhandlingen. Eftersom temperatur-mätområdet är stort och den röda, gröna och blå kanalen är känsliga för temperaturförändringar (liten förändring av temperatur ger stor förändring i uppmätt emission) så kommer kravet på det dynamiska omfånget av sensorn vara högt.  Ett alternativ till RGB-kameran, som fortfarande har en enkel uppställning, är en dubbel-sensor-kamera med ett dubbelt bandpass-filter i det när-infraröda (NIR) området. Detta kräver dock en utredning för hur sensorer i detta område påverkar den uppmätta signalen.
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Batterham, Ian, and n/a. "Office Copying 1950-1970 : thermographic processes, their deterioration and preservation." University of Canberra. School of Resource, Environmental & Heritage Sciences, 2000. http://erl.canberra.edu.au./public/adt-AUC20060607.171830.

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This work looks at a range of copying processes used between 1950 and 1970 and which can be gathered under the heading 'Thermography'. Thermography is a broad term covering those processes which utilise heat to produce their image. The main aims of the work were: to examine how and when each process was used; to determine the chemistry of each process; to examine the permanence of existing copies produced using the various processes; and to look at possible ways of improving the preservation prospects of these copies. These aims were addressed through both primary and secondary research mechanisms. Research included examination of documentary source material, seeking out persons with first hand knowledge of the development of the processes, as well as analysis of extant copies from the various processes. Finally a series of preliminary experiments into the aging properties of the papers and the possibilities of preservation through the use of protective materials were carried out.
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Alqudah, A. A. "Thermographic investigation of modern dental resin composite materials in-vitro." Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269038.

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Tanaka, Atsushi. "Thermographic Studies on the "Essential Work of Fracture" of Paper." Kyoto University, 1998. http://hdl.handle.net/2433/182409.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第7503号
農博第1015号
新制||農||768(附属図書館)
学位論文||H10||N3196(農学部図書室)
UT51-98-U170
京都大学大学院農学研究科林産工学専攻
(主査)教授 松本 孝芳, 教授 増田 稔, 教授 奥村 正悟
学位規則第4条第1項該当
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Gladman, Aviv Shlomo. "Infrared thermographic measurement of the SAR patterns of interstitial hyperthermia applicators." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq28844.pdf.

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Andersen, Ted Thanning. "A study of thermographic phosphor thermometry in an operating turbofan engine." Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-02132009-171409/.

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Thomas, Anton F. (Anton Felipe) 1977. "Anomaly edge effects in thermographic nondestructive testing of polymeric composite sandwich panels." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/89365.

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Littlejohn, Robin Anne Nicole. "Thermographic Assessment of the Forearm During Data Entry Tasks: A Reliability Study." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/35279.

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Work-related musculoskeletal disorders (WMSDs) negatively impact workerâ s health, ability to work, and their quality of life. Non-invasive methods for assessing the physiological responses to workload may provide information on physiological markers leading to increased risk of WMSDs. The following study aimed to evaluate the feasibility of using thermography to quantify differences in thermal readings of participants during and following a data entry task and assess the repeatability of thermal readings. Skin surface temperature measurements of the dorsal forearm were obtained from 12 participants (6 females, 6 males) during a data entry task (35 minutes) and a 30-minute post-task period. Participants also reported their perceived forearm discomfort during data entry and recovery. Three forearm analysis regions were analyzed based on statistical findings; Upper Left, Lower Left and Right regions. Temperature trends were found to increase during data entry and decrease during recovery. The Upper Left region was warmer during both data entry and recovery phases in comparison to the other regions. Repeatability of surface temperatures, based on intraclass correlations (ICCs), was found to be fair for magnitudes and trends during data entry, and poor for magnitudes and trends during recovery, despite higher significant correlations in the latter. Positive correlations were evident between subjective feelings of forearm discomfort trends and temperature trends in response to workload. No gender differences were found with regard to temperature measurements. This work contributes to the understanding of surface responses of the forearm during and following an applied stress, and to the literature supporting thermography as a non-invasive evaluative tool for assessing physiological responses during job tasks.
Master of Science
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19

Loh, S. F. "The use of image derotation techniques and liquid crystal thermography to visualise the temperature patters of warm stationary and rotating components." Thesis, University of Strathclyde, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371959.

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Loh, M. J. "Application of Statistical Pattern Recognition techniques to analysis of thermograms." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382226.

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Lee, Hyunchang [Verfasser], Andreas [Akademischer Betreuer] Dreizler, and Burak [Akademischer Betreuer] Atakan. "Thermographic PIV for Turbulent Flux Measurement / Hyunchang Lee. Betreuer: Andreas Dreizler ; Burak Atakan." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2016. http://d-nb.info/1112332898/34.

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Rösner, Henrik [Verfasser]. "Thermographic Nondestructive Evaluation of Early Stages Fatigue Damage in Titanium Material / Henrik Rösner." Aachen : Shaker, 2004. http://d-nb.info/1172609411/34.

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Fu, Jiyuan. "Using Thermographic Image Analysis in Detection of Canine Anterior Cruciate Ligament Rupture Disease." Thesis, Southern Illinois University at Edwardsville, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1582920.

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Anterior cruciate ligament (ACL) rupture is a common trauma which frequently happens in overweight dogs. Veterinarians use MRI (Magnetic resonance imaging) as the standard method to diagnose this disease. However MRI is expensive and time-consuming. Therefore, it is necessary to find an alternative diagnostic method. In this research, thermographic images are utilized as a prescreening tools for the detection of ACL rupture disease. Meanwhile, a quantitative comparison is made of new feature vectors based on Gabor filters with different frequencies and orientations.

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Fond, Benoit. "Simultaneous temperature and velocity imaging in turbulent flows using thermographic phosphor tracer particles." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/24952.

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Combined measurements of velocity and temperature are essential to improve our understanding of turbulent flows involving heat transfer or chemical reactions. However, performing such measurements is a very difficult task. The presence of particles, which are seeded into the flow as tracers for the flow velocity, strongly interferes with classic optical thermometry techniques such as Rayleigh scattering. A review of the current approaches shows that a technique that can measure both quantities simultaneously, in two dimensions and over a wide range of flow conditions is yet to be found. An alternative approach to this problem, presented in this dissertation, uses tracer particles made of temperature-sensitive luminescent material, which are capable of also indicating the gas temperature. Thermographic phosphors are shown to be clear candidates for this concept. Made of ceramic material, they are chemically inert and survive low and high temperature environments. The temperature has a strong influence on the luminescence process allowing various ways to perform thermometry Currently, phosphors are used for surface temperature measurements, but a phosphor suitable for two-dimensional measurements in turbulent flows must meet stringent requirements in terms of luminescence properties. In this respect, the temperature dependence of the emission spectrum, a high quantum efficiency and a short lifetime are essential. Micrometre-size refractory particles are widely used for PIV and are able to follow the fluid motion without slip for a wide range of fluid velocities and turbulence intensities However, for the concept to be valid, the ability of phosphor particles to follow fluctuations in the gas temperature must be demonstrated. Using theoretical heat transfer models, it is shown that the temperature response of a particle is faster than its velocity response irrespective of the gas temperature. These response times have a quadratic dependence on the particle diameter so only small particles can be used. Various aspects of the practical implementation of the flow measurement concept, such as the excitation, particle seeding, detection, image processing and calibration, are considered, tested and developed, with the objective of providing high signal levels and to permit precise, accurate, and highly resolved measurements. In order to determine whether a sufficient signal level can be obtained for a reasonable particle seeding density, i.e. that does not have any effect on the gas properties, a particle counting tool is implemented. This system is used to characterise the phosphorescence intensity of 2 μm diameter particles made of BAM:Eu2+, a phosphor with very advantageous properties for flow measurements. It is shown that a seeding density comparable to that of conventional PIV and relatively small laser fluence provide sufficient signal levels for precise single shot measurements. The technique is demonstrated in a turbulent heated jet from 300 K to 700 K. Single shot measurements of temperature and velocity are presented with a single-shot, single-pixel temperature precision of 2-5 %, a temperature accuracy of 2%, and a spatial resolution of 400 μm. An additional concept is explored. By seeding two streams with different materials, the phosphorescence signal can be used to visualise the turbulent mixing between the streams. This concept is demonstrated in the same turbulent heated jet. Future developments and applications of the thermographic phosphor tracer particle concept are discussed. Owing to the very wide variety of thermographic phosphors, the results presented in this dissertation constitute a solid foundation for the expansion of this promising technique.
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Abram, Christopher. "High repetition rate temperature and velocity imaging in turbulent flows using thermographic phosphors." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/29181.

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Turbulent flows involving heat transfer and chemical reactions are prevalent in a huge range of applications such as combustors and engines, boilers, and heating and cooling devices. Directly measuring important variables using laser-based techniques has significantly contributed to our understanding of the underlying flow physics. However, many flows of interest exhibit infrequent or oscillatory behaviour, such as flame extinction or instabilities in thermal boundary layers. Capturing the flow dynamics requires simultaneous, two-dimensional temperature and velocity measurements at sampling rates commensurate with turbulent timescales. Typically this means measuring many thousands of temperature and velocity fields per second, yet there are no high repetition rate diagnostics for temperature imaging in practical, oxygen-containing systems, with the essential capability of simultaneous velocity measurements. This thesis presents a novel laser-based imaging technique based on thermographic phosphor particles. There are a huge variety of thermographic phosphors, which are solid materials with luminescence properties that can be exploited for remote thermometry. Here, phosphor particles are seeded into the flow as a tracer. An appropriate phosphor must be selected, and the particle size chosen so that the particle temperature and velocity rapidly assume that of the surrounding fluid. The particles are probed using high-speed lasers and their luminescence and scattering signals are detected using high-speed cameras to measure the flow temperature and velocity at kHz repetition rates. The development of this method is described in detail. Using the thermographic phosphor BAM:Eu, examples of simultaneous time-resolved measurements are presented in turbulent air flows between 300 and 500 K, consisting of a heated jet (Re = 10,000) and also a flow behind a heated cylinder (Re = 700). The technique permits kHz-rate temperature imaging in oxygen-containing environments. These combined diagnostics currently provide a unique capability for the investigation of transient, coupled heat and mass transfer phenomena in turbulent flows of practical engineering importance. A second objective of this work is to improve the precision of the temperature measurement. The characterisation of a different thermographic phosphor with a high temperature sensitivity, zinc oxide (ZnO), is also reported. Temperature imaging using these tracer particles is demonstrated in a jet (Re = 2,000) heated to 363 K, with a temperature precision of 1%. This extends the capabilities of this versatile technique toward the study of flows with small temperature variations. Also, unlike the majority of phosphors previously investigated for thermometry, this phosphor is a semiconductor. Exploiting the temperature-dependent luminescence of this class of materials presents interesting new opportunities for remote temperature sensing.
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Altmann, Bettina [Verfasser]. "Image-Based Controlled Derotator for Kinematic and Thermographic Analysis Applied to Bearings / Bettina Altmann." Garbsen : TEWISS - Technik und Wissen GmbH, 2020. https://www.tewiss-verlag.de/.

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Warfield, Steven C. "Evaluation of thermographic techniques for the detection of subsurface delaminations in concrete bridge substructures." Thesis, Virginia Tech, 1991. http://hdl.handle.net/10919/41518.

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This thesis presents both an analytical and an experimental evaluation of the feasibility of using infrared thermographic techniques to detect subsurface damage in concrete. Various methods of artificial heating, required to effectively apply this technique, are presented. Four major conclusions are reached in this study. 1) Normal ambient diurnal atmospheric temperature changes are not generally sufficient to produce a measurable response in bridge substructures. 2) Heating by an infrared heat source is a technically viable artificial method provided some type of surface preparation is made to assure uniform emissivity. 3) Hot air heating is a viable technical alternative which does not require surface preparation prior to the application of heat. However, this method does require some type of enclosure to produce a hot air pocket. 4) Artificial heating methods based on heating blankets are not a feasible method due to local nonuniform heating effects.
Master of Science
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Nylund, Sophie, and Zahra Barbari. "Study of defects in PV modules : UV fluorescence and Thermographic photography for Photovoltaics (PV) Field Application." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-44120.

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For a PV plant it is of fundamental importance that the operation of the PV modules is free from faults or at least that the faults can be detected early, to ensure efficient electricity production. Some defects such as cracks can be seen in visible light while microcracks and damage to the silicon material can only be seen through special lighting. This study focuses on the most common defects in photovoltaic (PV) systems. Compare the infrared (IR) technology with the new ultraviolet (UV) fluorescence image technique for PV characterization, based on their accuracy and uncertainty factors under an experimental field investigation. In this study, first a literature study was conducted to the most common defects in PV system and their impact on electricity generation. Then a simulation model of a PV system was created in PVsyst and exported to Microsoft Excel which was used to evaluate how different defects at different stages of the PV cell's life cycle impact electricity generation, performance parameters and economic exchange. Furthermore, experiments with UV and IR was implemented at a PV system located in Dalarna and some PV modules at MDH. It was conducted that occurrence of snail tracks, delamination and hot spots in combination with bypass failures and non-functioning cell will affect the economic profitability in the long run and the payback time will increase since their impacts on electricity generation and performance parameters are huge. The worst case is when PV modules are affected by the fault in bypass diode and non-functioning cell which result to a payback time longer than the module's lifetime and huge amount electricity losses in different bypass diodes configurations. Since UV and IR are two different methods that are performed in two different ways, different errors occurred during the measurements. The biggest external factor was the weather that determined if the experiment could be implemented. The IR method gave decent results and was quicker to use, but the UV method highlighted some defect which could not be seen with the IR technology.
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Sale, Martin William Briddon. "The assessment of the photo response efficiency of the silver halide component in a photo-thermographic material." Thesis, University of Westminster, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263935.

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Albrecht, Hendrik [Verfasser]. "Determination of spatial and temporal water relations in single leaves and canopies based on thermographic measurements / Hendrik Albrecht." Bonn : Universitäts- und Landesbibliothek Bonn, 2016. http://d-nb.info/1122193963/34.

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Gómez, Sandra [Verfasser]. "Infection and spread of Peronospora sparsa on Rosa sp. (Berk.) : a microscopic and a thermographic approach / Sandra Gómez." Bonn : Universitäts- und Landesbibliothek Bonn, 2014. http://d-nb.info/1047666537/34.

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Frattina, Valerio. "Development and application of simultaneous 2D flow velocity and gas temperature measurements using thermographic phosphors under engine-relevant conditions." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC073.

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Dans le cadre de cette thèse, une tech-nique de diagnostic optique a été développée pour mesurer simultanément la température et la vitesse de gaz dans un moteur thermique trans-parent.La technique de la PIV-thermographique (T-PIV) combine la thermométrie par phosphores-cence et la vélocimétrie par image de particules (PIV) et offre la possibilité de mesurer simulta-nément la température et la vitesse du gaz. Le matériau luminophore approprié a été choisi en testant trois luminophores disponibles dans le commerce : BAM:Eu2+, ZnO et ZnO:Zn.L'émission lumineuse et la réponse spectrale à divers paramètres, y compris la température, ont été mesurées dans un écoulement gazeux ense-mencé de particules afin de reproduire les con-ditions rencontrées typiquement dans un mo-teur. Cela à permis d’obtenir une courbe d'éta-lonnage dépendante de la température à utiliser dans les expériences sur moteur. Les particules de ZnO:Zn montrent une sensibilité relative-ment plus forte à la température permettant une précision plus élevée sur la mesure de tempéra-ture.Pour ces raisons, le ZnO:Zn a été choisi comme candidat approprié pour les mesures dans le mo-teur transparent.Les mesures ont été effectuées à un régime mo-teur de 1200 tr/min avec une fréquence d'échan-tillonnage de 10 Hz entre 180 et 540°vil sans combustion.Les champs de température et de vitesse ont été mesurés avec succès à différents angles vilebre-quin pendant la phase de compression et de dé-tente. Les champs de température obtenus expé-rimentalement sont comparés aux températures obtenues à partir d'une simulation 0D montrant un écart de température d'environ 1% (200°vil) et de 14% (480°vil) par rapport au modèle de si-mulation. La précision de mesure estimé est de 55 K (18%) à 300 K et de 2 K (0.3%) à 614 K sur une moyenne de 200 cycles.La T-PIV a également été testé pour mesurer la température des gaz en post-combustion. Dans ce cas, les mesures étaient impossibles, proba-blement en raison d’une dégradation du maté-riau luminophore utilisé qui ne résiste pas aux températures élevées de la combustion. Les perspectives de développements futurs qui ré-sultent de ces résultats sont la sélection d’un lu-minophore capable de résister à plus hautes tem-pératures.Enfin, la technique montre un grand potentiel de développement dans un environnement moteur
A non-intrusive laser diagnostics technique has been developed for simultaneous measurements of velocity and gas temperature in optically accessible internal combustion en-gines. The technique, thermographic PIV (T-PIV) combines phosphor thermometry and particle image velocimetry (PIV) and offers the possibility of simultaneous measurement of gas temperature and velocity.Suitable phosphor materials were selected by testing three commercially available phosphors: BAM:Eu2+, ZnO and ZnO:Zn. The lumines-cence emission and the spectral response to var-ious parameters including temperature were measured yielding a temperature-dependent cal-ibration curve to be used for signal interpreta-tion in engine experiments. The ZnO:Zn phos-phor shows the highest sensitivity to tempera-ture allowing higher temperature precision. Therefore, ZnO:Zn phosphor was chosen as the suitable candidate for engine measurements.Measurements were performed in an internal combustion engine at a speed of 1200 rpm with a sampling rate of 10 Hz between 180 and 540°CA under motored conditions. The temper-ature and velocity fields were measured success-fully at various times throughout the compres-sion and the exhaust stroke. The obtained tem-perature fields are compared with simulated bulk-gas temperatures from a 0D model-based simulation showing a temperature deviation of around 1% (200°CA) to 14% (480°CA) from the model. The measurement accuracy was found to be 55 K (18%) at 300 K and 2 K (0.3%) at 614 K for the 200-cycles average.The potential of the diagnostics was tested also in in cylinder post-combustion gases. In this case, the diagnostics was failing probably due to the characteristics of the phosphor used, which does not seem to resist to high combustion tem-peratures degrading its luminescence properties. The potential of T-PIV in post-combustion gases remains under the conditions of finding more resistant phosphor particles
In der vorliegenden Arbeit wurde eine nicht-intrusive Methode der Laserdiagnostik zur simultanen Messung von Gasgeschwindigkeit und -temperatur in einem optisch zugänglichen Verbrennungsmotor entwickelt und getestet. Diese Messmethode der thermographischen PIV (T-PIV) kombiniert Phosphorthermometrie mit Particle Image Velocimetry (PIV) und ermöglicht die simultane Messung von Geschwindigkeit und Temperatur eines Gases.Im Verlauf der Arbeit wurden drei kommerziell verfügbare Phosphormaterialien für die Motorexperimente getestet: BAM:Eu2+, ZnO and ZnO:Zn. Die optischen Eigenschaften und die Spektralantwort des Phosphors auf Parametervariationen wie Temperaturänderungen wurden gemessen. Daraus wird eine temperaturabhängige Kalibrationskurve erstellt, die zur Temperaturmessung im Motor dient. Der Phosphor ZnO:Zn wurde für Temperaturmessungen im Motor ausgewählt, da die optischen Eigenschaften des Phosphors die größte Sensitivität zu Temperaturänderungen aufweisen.In einem Verbrennungsmotor wurden Temperaturmessungen bei 1200 U/min und 10 Hz unter geschleppten Bedingungen zwischen 180°KW und 540°KW durchgeführt. Geschwindigkeit und Temperatur des Gases wurden an mehreren Kurbelwinkeln während des Verdichtungs- und Expansionstaktes gemessen und die Gastemperatur mit der Restgastemperatur einer 0D Simulation verglichen. Die Abweichung zwischen Mess- und Simulationsergebnissen beträgt 1% (200°KW) und 14% (480°KW). Die Messgenauigkeit für den Mittelwert über 200 Messzyklen beträgt 55 K (18%) bei 300 K und 2 K (0.3%) bei 614 K.Die Messmethode wurde außerdem zur Restgastemperaturmessung im gefeuerten Betrieb des optischen Motors angewandt. Jedoch konnte unter diesen Bedingungen keine validen Messungen durchgeführt werden, da der Phosphor möglicherweise bei Verbrennungstemperaturen degradiert und die Lumineszenz-Eigenschaften verändert werden. Eine erfolgreiche Anwendung von T-PIV unter motorischen Bedingungen wird künftig unter der Voraussetzung möglich sein, dass verbrennungsresistente Phosphormaterialien gefunden werden
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Dahal, Rohini. "Bilateral Thermographic Image Comparison Software Tool for Pathology Detection in Canines with Application to Anterior Cruciate Ligament (ACL) Rupture." Thesis, Southern Illinois University at Edwardsville, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10276314.

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Introduction: The bilaterally symmetry property in animals can be used to detect pathologies where body parts on both sides can be compared. For any pathological disorder, thermal patterns differ compared to the normal body parts. A software application for veterinary clinics is under development to input two thermograms of body parts on both sides, one normal and the other unknown, and the application compares them on the basis of extracted features and appropriate similarity and difference measures and outputs the likelihood of pathology. Previous research has been used to determine the appropriate image processing, feature extraction and comparison metrics to be used. The comparison metrics used are the vector inner product, Tanimoto, Euclidean, city block, Minkowski and maximum value metric. Also, results from experiments with comparison tests are used to derive a potential threshold values which will separate normal from abnormal images for a specific pathology.

Objectives: The main objective of this research is to build a comparison software tool application by combining the concepts of bilateral symmetrical property in animals and IR thermography that can be for prescreening in veterinary clinics.

Comparison Software Tool Development: The comparison software tool was developed for veterinary clinics as a prescreening tool for pathology detection using the concepts of thermography and bilateral symmetry property in animals. The software tool has a graphical user interface (GUI) that allows ease of use for the clinical technician. The technician inputs images or raw temperature data csv files and compares thermographic images of bilateral body parts. The software extracts features from the images and calculates the difference between the feature vectors with distance and/or similarity metrics. Based upon these metrics, the percentage deviation is calculated which provides the deviation of the unknown (test) image from the known image. The percentage deviation between the thermograms of the same body parts on either side provides an indication regarding the extent and impact of the disease [Poudel; 2015]. The previous research in veterinary thermography [Liu; 2012; Subedi; 2014, Fu; 2014, Poudel; 2015] has been combined with the real world veterinary clinical scenario to develop a software tool that can be helpful for researchers as well as for the clinical technicians in prescreening of pathologies.

Experimental Results and Discussion: Experiments were performed on ACL thermograms to determine a threshold that can separate normal and abnormal ACL images. 18-colored Meditherm images had poor results and could not suggest any threshold value. But results were positive for temperature remapped 256 gray level Meditherm images which suggested the 40% of percentage deviation could produce a separation. The total number of Normal - Normal pairs were greater than total number of Normal – Abnormal pairs below 40% deviation. Similarly, total number of Normal –Abnormal pairs of images were greater than total number of Normal – Normal pairs above 40%. This trend was consistent for Euclidean distance, maximum value distance and Minkowski distance for both texture distances of 6 and 10. The performance in terms of sensitivity and specificity was poor. The best sensitivity of 55% and best specificity of 67% was achieved. This indicates better results for predicting the absence of ACL rupture then actually finding the disease. In this case the software could be used by the clinician in conjunction with other diagnostic methods.

Conclusion: The Experiments, results and analysis show that the comparison software tool can be used in veterinary clinics for the pre-screening of diseases in canines and felines to estimate the extent and impact of the disease based upon the percentage deviation. However, more research is necessary to examine its efficacy for specific pathologies. Note that the software can be used by researchers to compare any two images of any formats. For ACL experimentation, there are indication that a threshold value is possible to separate normal from abnormal and the spectral, texture and spectral features suggested by researches [Subedi; 2014, Liu; 2012, Fu; 2014, Poudel; 2015] are not sufficient to determine that threshold with the given image database.

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Islam, Md Zahirul. "Fatigue Behavior of Flax Fiber Reinforced Polymer Matrix Composites." Thesis, North Dakota State University, 2019. https://hdl.handle.net/10365/31577.

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Bio-based flax fiber polymer composites (FFPC) have the potential to replace metals and synthetic fibers in certain applications due to their unique mechanical properties. However, the long term reliability of FFPC needs to be better understood. In this study, the fatigue limit was evaluated using mathematical, thermographic, and energy-based approaches. Each approach determined fatigue limits around 45% load of ultimate tensile strength at a loading frequency of 5 Hz. Thermographic and energy-based approaches were also implemented at different loading frequencies (5, 7, 10, and 15 Hz) to define the effect of loading frequency on the fatigue life. Fatigue limit was found to decrease slowly with increasing loading frequency. Moreover, two forms of damage energy (thermal and micro-mechanical) during cyclic loading was separated using an experimental approach to pinpoint the main responsible damage energy for decreasing fatigue limit with increasing loading frequency.
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Monchau, Jean-Pierre. "Mesure d'émissivité pour la thermographie infrarouge appliquée au diagnostic quantitatif des structures." Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1128/document.

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La thermographie infrarouge constitue un outil de diagnostic très utile dans le domaine du bâtiment et du génie civil. Cependant un diagnostic quantitatif reste difficile, et l'émissivité des surfaces étudiées joue un rôle important. Le présent travail est une étude sur la mesure d'émissivité pour le diagnostic quantitatif des structures par thermographie. Un des enjeux est de compléter une base de données d'émissivité pour des matériaux du bâtiment et du génie civil ; pour cela il a été nécessaire de développer des appareils de mesure portables. Deux appareils ont été développés au CERTES, utilisant des méthodes indirectes. Ces méthodes consistent à mesurer la réflexion d'un flux infrarouge modulé et nécessite une référence de réflectance connue. Le premier appareil module le flux par modulation lente de température (mesure en 16mn) ; il est adapté aux surfaces diffusantes et hétérogènes comme les bétons bitumineux et les matériaux de construction du bâtiment. L'autre appareil utilise un système d'écran permettant une modulation plus rapide (mesure en quelques secondes). Il est plus polyvalent. Il est aussi plus facilement transportable et permet également d'obtenir une évaluation du caractère plus ou moins spéculaire de la surface. Ces deux appareils couvrent au choix une bande spectrale large (1 à 40µm) pour évaluer les propriétés radiatives des surfaces et une bande étroite (8 à 14µm) adaptée à la sensibilité des caméras infrarouges. Une étude comparative sur les mesures d'émissivité a été entreprise avec le LNE (Laboratoire National de Métrologie et d'Essais). Les échantillons utilisés pour cette étude comparative ont permis de tester les différents dispositifs pour des matériaux ayant des propriétés radiatives très variées. Des mesures ont été effectuées au laboratoire et sur site sur une large gamme de matériaux usuels du bâtiment et du génie civil
Thermography is a very useful diagnosis tool in buildings and civil engineering structures. However quantitative diagnosis remains difficult, and having accurate values of surface emissivity is an important factor. The present work is a study about emissivity measurement for quantitative diagnosis with thermography. We needed accurate measurement of the emissivity of a number of civil engineering materials, in order to create a database. Thus, it was necessary to develop new portable measurement devices. Two devices using an indirect measurement method were developed at CERTES laboratory. The method uses the measurement of the reflectivity from a modulated IR source and requires calibration with a highly reflective surface. The first device uses a low-frequency, thermal modulation well-adapted to laboratory measurements, whereas the second one is a portable system using a mechanical modulation at a faster frequency, more appropriate to outdoor measurements. Both devices allow measurements in the broad (1—50µm) and narrow (8—14µm) bands. Experiments were performed on a large number of materials commonly used in buildings and civil engineering structures. The final objective of this work is to build a database of emissivity for these materials. A comparison of laboratory and on-site measurements of emissivity values obtained in both spectral bands is presented along with an estimation and an analysis of measurement uncertainties. A comparative study with measurement obtained at LNE (Laboratoire National de Métrologie et d'Essais, French laboratory of metrology) was performed, using a range of materials with widely different radiative properties. An analysis of discrepancies and their possible causes is presented
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AlBatayneh, Ola B. "Assessment of Er:YAG laser application for cavity preparation in the primary and permanent dentition : a scanning electron microscopic and thermographic study /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19177.pdf.

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Ojo, Anthony Oladeji. "A new laser-based technique for simultaneous time-resolved point measurements of flow temperature and velocity using thermographic phosphor tracer particles." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/62813.

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Turbulent flows involving heat transfer or chemical reactions are important processes in the operation of numerous devices such as engines, and heating and cooling systems. Laser-based measurements of flow temperature and velocity have aided our understanding of the underlying flow physics in such processes. Recently, micron-size thermographic phosphor tracer particles, which are solid materials with temperature-dependent luminescence properties, have been exploited for simultaneous temperature and velocity imaging. However, the measurement strategy, which requires pulsed lasers to illuminate and excite the particles, is typically implemented at low temporal (~10 Hz) and spatial resolutions (>400 μm). Also, it is difficult to implement the technique for near-wall measurements or where limited optical access is required. In this dissertation, an alternative and complementary single-point measurement technique is presented, also based on thermographic phosphor particles. Here, particles seeded in a flow are probed individually when crossing a probe volume formed using continuous wave (CW) lasers. Using photomultiplier tubes to detect the scattering and luminescence signals from the same particle, velocimetry and thermometry are performed simultaneously, at sampling rates up to kHz’s and spatial resolution of 150 μm using a combined laser Doppler velocimetry and phosphor thermometry technique. The development of this measurement technique, based on the two-colour ratio strategy in phosphor thermometry is first described. The technique is demonstrated, using the phosphor BaAl10Mg17:Eu2+, in a heated jet from 293 - 670 K with temperature precision of 4-8%, and accuracy better than 2%. The utility of the technique is further demonstrated for near-wall measurement with accurate measurements performed as close as 200 μm from a heated surface. Another temperature evaluation strategy, which exploits the temperature dependence of the luminescence lifetime, by probing the phase-shifted luminescence from the same phosphor particles when using a modulated excitation source, is also described. The concept is demonstrated in a heated jet above 600 K, with a measurement precision as high as 1% obtained at 840 K. A discussion on applications and future developments of the concept of the ‘thermographic laser Doppler velocimetry’ is also provided.
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Lawrence, Martin. "Development of the gas phase laser induced phosphorscence technique and soot measurements in flame using laser induced incandescence." Thesis, Brunel University, 2013. http://bura.brunel.ac.uk/handle/2438/10540.

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Thermometry measurements were carried out using planar laser induced phosphorescence in conjunction with thermographic phosphors in heated turbulent jets and laminar flames in order to further develop the technique for usage in flames. Two dimensional thermometry measurements are essential to improve the understanding of combustion processes, as temperature governs soot pyrolysis, leading to soot formation. Two particular thermographic phosphors, BAM and YAG:Dy were tested and compared and it was found that they were unsuitable for gas phase flame thermometry measurements. Soot volume fraction measurements were carried out using planar two colour laser induced incandescence in gaseous and liquid fuel flames. The gas fuel flames were diluted with nitrogen, carbon dioxide and hydrogen individually and then with nitrogen and hydrogen together, as well as carbon dioxide and hydrogen together, separately. Results revealed the dilution effects of the gases on the soot formation process, where increasing nitrogen percentage in the flow decreased SVF, carbon dioxide reduced it further and hydrogen showed no marked difference. Biodiesels were compared with each other and with diesel in a wick burner in order to analyse their compositional effects on soot. Biodiesel composition was measured using gas chromatography. The sooting tendencies of the biodiesels were as expected, fuels with a longer average carbon chain length and a higher degree of unsaturation were found to produce more soot than shorter, more saturated fuels. Diesel was sootier than all of the biofuels tested, due to containing aromatics and a lower oxygen content. A pilot study was also done, where the performance and emissions of biofuels and biofuel-diesel blends were tested in a gas turbine engine, in order to relate the investigation to real world situations.
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Oketch, Peter Obara [Verfasser], and Burak [Akademischer Betreuer] Atakan. "Heat transfer from laminar premixed flames to cylindrical walls: Experimental studies using thermographic phosphors and micro-thermocouples / Peter Obara Oketch ; Betreuer: Burak Atakan." Duisburg, 2020. http://d-nb.info/1216827109/34.

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Frattina, Valerio [Verfasser], and Christof [Akademischer Betreuer] Schulz. "Development and application of simultaneous 2D flow velocity and gas temperature measurements using thermographic phosphors under engine-relevant conditions / Valerio Frattina ; Betreuer: Christof Schulz." Duisburg, 2020. http://d-nb.info/1215032358/34.

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Dalsass, Manuel [Verfasser], Christoph J. [Akademischer Betreuer] Brabec, and Christoph J. [Gutachter] Brabec. "Quality Assessment of Large-scale Photovoltaic Generators Based on Inverter Data and Thermographic Inspections / Manuel Dalsass ; Gutachter: Christoph J. Brabec ; Betreuer: Christoph J. Brabec." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2019. http://d-nb.info/1177368676/34.

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42

DEAK, F. L. G. B. "Efeito das fases reprodutivas e períodos do ano na temperatura do corpo, prenhez e componentes do leite em vacas da raça Holandês Preto e Branco." Universidade do Oeste Paulista, 2017. http://bdtd.unoeste.br:8080/jspui/handle/jspui/997.

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The objective of this study was to study the influence of the periods of the year and reproductive phases on body temperature, pregnancy and milk components of cows of the Black and White Dutch breed. Cows (n = 24) of the Black and White Dutch breed aged 5.0 ± 1.3 years were used in the reproductive stages: 1 (1-95 days of pregnancy); 2 (96-190 days of pregnancy); 3 (191-285 days of pregnancy); 4 (puerperium) and 5 (non-pregnant cows), kept on pasture of Urochloa decumbens, corn silage, mineral mixture and water at will. The experiment period was 365 days, dry period (April to September) and rainy (October to March). Infrared thermography of body areas was performed every 28 ± 5 days, followed by rectal thermometry, ultrasonography for the diagnosis of pregnancy, measurement of climatic parameters, CMT examination and milk collection to study its composition. Statistical analysis was performed using the Tukey test at the significance level of 5% and in the Leeds stadium comparison. For temperatures obtained by thermograms there were differences (P <0.05) between periods of the year and reproductive phases. For the flank, lateral udder and perineal temperatures there were differences (P <0.05) between periods of the year. The udder, perineum and rectal temperatures differed for reproductive phases (P <0.05). There were significant correlations (P <0.01) between: reproductive phase with rectal temperature, ocular globe, muzzle, flank and perineum. The CMT correlated with the temperature of the different reproductive phases presented significant differences (P <0.05) in all the reproductive phases during the rainy season, there were positive correlations (P <0.01) between CMT and CCS. It was concluded that the areas of the body examined by thermographic images presented different temperatures, showing physiological variations that aid in the clinical evaluation of each of the examined areas. Infrared thermography images have also been shown to detect changes in skin surface temperature in response to varying degrees of severity of mammary gland infection, as CMT suggests. The periods of the year and reproductive phases influenced the temperature of areas of the body of milk cows. The image processing was practical, and routine thermography examination was recommended as a complement to the clinical examination.
Objetivou-se estudar a influência dos períodos do ano e fases reprodutivas na temperatura de áreas do corpo, prenhez e componentes do leite de vacas da raça Holandês Preto e Branco. Foram utilizadas vacas (n=24) da raça Holandês Preto e Branco com idade de 5,0±1,3 anos, nas fases reprodutivas: 1(1-95 dias de prenhez); 2 (96-190 dias de prenhez); 3 (191-285 dias de prenhez); 4 (puerpério) e 5 (vacas não prenhes), mantidas em pastagem de Urochloa decumbens, silagem de milho, mistura mineral e água à vontade. O período do experimento foi de 365 dias, período seco (abril a setembro) e chuvoso (outubro a março). Termografia de infravermelho de áreas do corpo foi realizada a cada 28±5 dias, seguido de termometria retal, ultrassonografia para o diagnóstico de prenhez, mensuração de parâmetros climáticos, exame de CMT e coleta de leite para estudo da sua composição. A análise estatística utilizou-se do teste Tukey ao nível de significância de 5% e na comparação estádio Leeds. Para as temperaturas obtidas por termogramas houve diferenças (P <0,05) entre períodos do ano e fases reprodutivas. Para as temperaturas do flanco, úbere lateral e períneo houve diferenças (P <0,05) entre períodos do ano. As temperaturas do úbere, períneo e temperatura retal diferiram para fases reprodutivas (P <0,05). Houve correlações significativas (P <0,01) entre: fase reprodutiva com temperatura retal, globo ocular, mufla, flanco e períneo. O CMT correlacionado com a temperatura das diferentes fases reprodutivas apresentou diferenças significativas (P<0,05) em todas as fases reprodutivas durante a estação chuvosa, houve correlações positivas (P<0,01) entre o CMT e a CCS. Conclui-se que as áreas do corpo examinadas por imagens termográficas apresentaram diferentes temperaturas, mostrando variações fisiológicas que auxiliam na avaliação clínica de cada uma das áreas examinadas. As imagens de termografia por infravermelho também se revelaram sensíveis para detectar alterações de temperatura na superfície da pele em resposta a graus variados de gravidade da infecção da glândula mamária, como sugere o CMT. Os períodos do ano e fases reprodutivas influenciaram na temperatura de áreas do corpo de vacas de leite. O processamento das imagens foi prático, sendo recomendado o exame de termografia na rotina como complementar ao exame clínico.
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43

Silva, Gabriela Fagundes da [UNESP]. "Rendimento da incubação e perda de calor dos ovos durante a transferência da incubadora para o nascedouro." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/137824.

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O incubatório de ovos tem grande importância na cadeia produtiva, pois é a partir dele que a cadeia produtiva de frango é abastecida. Assim, a ineficiência no incubatório afeta todo o segmento. Foi realizado um experimento com o objetivo de observar os efeitos da idade da matriz pesada sobre o rendimento de incubação e a perda de calor dos ovos durante o trajeto da sala de incubação até o nascedouro. Foram incubados ovos de matrizes pesadas da linhagem Cobb de três idades: 26, 32 e 53 semanas. Esses ovos foram separados em dois tratamentos, sendo T0 o tratamento controle, que respeitou os procedimentos adotados normalmente pela empresa incubadora e T1, que utilizou uma caixa térmica para o transporte dos ovos durante a transferência. Para ambos os tratamentos a transferência durou cerca de 10 minutos em todas as três repetições. Após o nascimento foi realizada a contagem dos pintos nascidos, dos ovos não eclodidos, os cálculos de eclosão e eclodibilidade, a quebra dos ovos não eclodidos para averiguar em qual momento do desenvolvimento ocorreu mortalidade embrionária, e o peso dos pintos nascidos. Os resultados obtidos mostraram que os ovos de 26 semanas tiveram maior infertilidade, o que fez com que a eclosão se apresentasse menor, a eclodibilidade e mortalidade não foram diferentes entre as idades. O peso dos pintinhos diferiu nas três idades mostrando que os pintinhos de matrizes mais velhas são mais pesados. Quanto à perda de calor, os resultados mostraram que todos os locais avaliados possuem temperatura e UR fora do recomendado na literatura, caracterizando o trajeto todo como ponto crítico para controle da temperatura, e que os ovos de T1 sofreram menos perda de calor nas transferências que os ovos de T0. Todavia, o tratamento com caixa térmica não proporcionou melhoria nos indicadores de eclodibilidade e peso de pintinho, para o tempo de transferência estudado.
The incubatory of eggs has great importance in the production chain, since it is the supplier of the production chain. Thus, inefficiency in the incubatory affects the entire production chain. An experiment was performed in order to observe the effects of the broiler breeders and the heat loss of the eggs during the transfer from the hatchery to the hatcher on the yield of the incubation. Eggs from three ages: 26, 32 and 53 weeks of Cobb broiler breeders were incubated. These eggs were separated into two treatments: T0 as the control treatment, which complied with the procedures normally adopted by the incubator company and T1 which used a cooler to transport the eggs during the transfer. For both treatments the transfer took about 10 minutes in all the three repetitions. After the birth it was made the counting of the hatched chicks, of the unhatched eggs, the calculations of hatching and hatchability, the breaking of the unhatched eggs; all to determine at what time of the development the embryonary mortality took place, and the weight of the hatched chicks. The results obtained showed that the eggs of the 26-week breeders had higher infertility, which led to the lower hatching. Hatchability and mortality did not differ between the ages. The weight of the chicks differed in the three ages showing that the chicks of older breeders were heavier. Regarding the heat loss, the results showed that all the places evaluated had temperature and RH out of the recommended in the literature, characterizing the whole route as critical for the temperature control, and that the eggs of T1 suffered less heat loss in the transfers than the T0 eggs. However, the treatment using the cooler did not improve the hatchability indicators and chick weight for the studied transfer time.
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44

Silva, Gabriela Fagundes da. "Rendimento da incubação e perda de calor dos ovos durante a transferência da incubadora para o nascedouro." Dracena, 2016. http://hdl.handle.net/11449/137824.

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Orientador: Danilo Florentino Pereira
Resumo: O incubatório de ovos tem grande importância na cadeia produtiva, pois éa partir dele que a cadeia produtiva de frango é abastecida. Assim, a ineficiência noincubatório afeta todo o segmento. Foi realizado um experimento com o objetivo deobservar os efeitos da idade da matriz pesada sobre o rendimento de incubação e aperda de calor dos ovos durante o trajeto da sala de incubação até o nascedouro.Foram incubados ovos de matrizes pesadas da linhagem Cobb de três idades: 26,32 e 53 semanas. Esses ovos foram separados em dois tratamentos, sendo T0 otratamento controle, que respeitou os procedimentos adotados normalmente pelaempresa incubadora e T1, que utilizou uma caixa térmica para o transporte dos ovosdurante a transferência. Para ambos os tratamentos a transferência durou cerca de10 minutos em todas as três repetições. Após o nascimento foi realizada a contagemdos pintos nascidos, dos ovos não eclodidos, os cálculos de eclosão eeclodibilidade, a quebra dos ovos não eclodidos para averiguar em qual momento dodesenvolvimento ocorreu mortalidade embrionária, e o peso dos pintos nascidos. Osresultados obtidos mostraram que os ovos de 26 semanas tiveram maiorinfertilidade, o que fez com que a eclosão se apresentasse menor, a eclodibilidade emortalidade não foram diferentes entre as idades. O peso dos pintinhos diferiu nastrês idades mostrando que os pintinhos de matrizes mais velhas são mais pesados.Quanto à perda de calor, os resultados mostrar... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The incubatory of eggs has great importance in the production chain,since it is the supplier of the production chain. Thus, inefficiency in the incubatoryaffects the entire production chain. An experiment was performed in order to observethe effects of the broiler breeders and the heat loss of the eggs during the transferfrom the hatchery to the hatcher on the yield of the incubation. Eggs from three ages:26, 32 and 53 weeks of Cobb broiler breeders were incubated. These eggs wereseparated into two treatments: T0 as the control treatment, which complied with theprocedures normally adopted by the incubator company and T1 which used a coolerto transport the eggs during the transfer. For both treatments the transfer took about10 minutes in all the three repetitions. After the birth it was made the counting of thehatched chicks, of the unhatched eggs, the calculations of hatching and hatchability,the breaking of the unhatched eggs; all to determine at what time of the developmentthe embryonary mortality took place, and the weight of the hatched chicks. Theresults obtained showed that the eggs of the 26-week breeders had higher infertility,which led to the lower hatching. Hatchability and mortality did not differ between theages. The weight of the chicks differed in the three ages showing that the chicks ofolder breeders were heavier. Regarding the heat loss, the results showed that all theplaces evaluated had temperature and RH out of the recomme... (Complete abstract click electronic access below)
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45

Visentini, Roberta. "Étude expérimentale des transferts thermiques en ébullition transitoire." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0106/document.

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L'ébullition est présente dans la vie de tous les jours et elle a été par conséquent le sujet de beaucoup d'études, mais pour la plupart en régimes stationnaires. Néanmoins, l'intérêt de connaître les caractéristiques de l'ébullition transitoire est aussi important notamment pour la prévention des accidents nucléaires majeurs. C'est justement dans l'optique de mieux comprendre les phénomènes d'ébullition qui se produisent lors d'un RIA (Accident d'Insertion de Réactivité) que cette thèse a été financée par l'IRSN. Le RIA est un accident qui peut résulter d'une défaillance du mécanisme de la grappe contrôlant la réaction nucléaire. La réaction s'emballe pendant quelques dizaines de millisecondes (pulse de puissance) provoquant une augmentation rapide de la température du crayon de combustible et donc l'évaporation du liquide qui l'entoure. Des tests ont été faits par le passé soit sur des crayons de combustibles, soit sur des tubes chauffés ayant les mêmes dimensions qu'un crayon, afin d'améliorer la connaissance de ce phénomène. Par contre, les mesures étaient entachées d'incertitudes importantes, dues à des techniques de mesure non appropriées à des phénomènes si rapides. L'objectif de ce travail a été de concevoir et mettre en place une expérience capable de simuler un RIA à petite échelle, pour mieux comprendre les caractéristiques de l'ébullition lorsque la paroi monte en température très rapidement. De plus, ce dispositif expérimental devait être apte à étudier des montées en température moins violentes pour améliorer la connaissance de l'ébullition transitoire en général. Cette expérience a été conçue à l'Institut de Mécanique des Fluides de Toulouse. Elle est constituée d'une feuille métallique d'acier de 50µm d'épaisseur, formée en demi cylindre (8mm de diamètre et 200mm de longueur) et chauffée par effet Joule. Elle est entourée par du fluide réfrigérant HFE7000, qui permet de travailler en similitude par rapport au cas réel en eau. Le fluide est confiné par un deuxième demi cylindre en verre, ayant 34mm de diamètre. Les expériences peuvent être en vase ou avec écoulement, écoulement qui a été caractérisé par des mesures PIV. Plusieurs débits peuvent donc être employés et le sous-refroidissement du liquide est aussi ajustable. L'emploi d'une alimentation pilotable et très flexible permet d'obtenir des chauffages du métal jusqu'à 2500K/s, mais aussi des montées en température plus faibles, pour tracer des courbes d'ébullition stationnaires ou faiblement transitoires. La température de la paroi est mesurée grâce à une caméra infrarouge, couplée à des visualisations rapides et à des mesures de pression et température dans le liquide
Boiling phenomena can be found in the everyday life, thus a lot of studies are devoted to them, especially in steady state conditions. Transient boiling is less known but still interesting as it is involved in the nuclear safety prevention. In this context, the present work was supported by the French Institute of Nuclear Safety (IRSN). In fact, the IRSN wanted to clarify what happens during a Reactivity-initiated Accident (RIA). This accident occurs when the bars that control the nuclear reactions break down and a high power peak is passed from the nuclear fuel bar to the surrounding fluid. The temperature of the nuclear fuel bar wall increases and the fluid vaporises instantaneously. Previous studies on a fuel bar or on a metal tube heated by Joule effect were done in the past in order to understand the rapid boiling phenomena during a RIA. However, the measurements were not really accurate because the measurement techniques were not able to follow rapid phenomena. The main goal of this work was to create an experimental facility able to simulate the RIA boiling conditions but at small scale in order to better understand the boiling characteristics when the heated-wall temperature increases rapidly. Moreover, the experimental set-up was meant to be able to produce less-rapid transients as well, in order to give information on transient boiling in general. The facility was built at the Fluid-Mechanics Institute of Toulouse. The core consists of a metal half-cylinder heated by Joule effect, placed in a half-annulus section. The inner half cylinder is made of a 50 microns thick stainless steel foil. Its diameter is 8mm, and its length 200mm. The outer part is a 34mm internal diameter glass half cylinder. The semi-annular section is filled with a coolant, named HFE7000. The configuration allows to work in similarity conditions. The heated part can be place inside a loop in order to study the flow effect. The fluid temperature influence is taken into account as well. A flexible power supply that can generate a free-shape signal, allows to get to a wall-temperature increase rate up to 2500 K/s but also to obtain lower rates, which permits to study weaker transients and steady state conditions. The thermal measurements are realised by means of an infra-red camera and a high-speed camera is employed in order to see the boiling phenomena at the same time. From the voltage and current measurements the heat flux that is passed to the fluid is known
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46

Mohammed, Mohammed Ahmed Alkhader [Verfasser], Burak [Akademischer Betreuer] Atakan, and Ernst von [Akademischer Betreuer] Lavante. "Experimental Investigation of the Heat Flux from Laminar Premixed Ethanol/Air and Hydrogen/Ethanol/Air Flames to Walls Using Thermographic Phosphors / Mohammed Ahmed Alkhader Mohammed. Gutachter: Ernst von Lavante. Betreuer: Burak Atakan." Duisburg, 2015. http://d-nb.info/1067055177/34.

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47

Schulze, Maren. "Thermographie am Huf." [S.l.] : [s.n.], 2003. http://www.diss.fu-berlin.de/2004/265/index.html.

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48

Daviot, Ronan. "Etude des champs de flux thermique sur les composants faisant face au plasma dans un tokamak à partir de mesures de température par thermographie infrarouge." Phd thesis, Ecole Centrale Paris, 2010. http://tel.archives-ouvertes.fr/tel-00534809.

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La connaissance des champs de flux thermique sur les composants d'un tokamak estun élément important de la conception de ce type de machines. L'objectif de cette thèse est dedévelopper et mettre en œuvre une méthode de calcul de ces flux à partir des mesures detempérature par thermographie infrarouge. Ce travail repose sur trois objectifs qui concernentles tokamaks actuels et futurs (ITER) : mesurer un champ de température d'une paroiréfléchissante par pyrométrie photothermique (pré-étude), caractériser les propriétésthermiques des dépôts sur les surfaces des composants et développer un calcultridimensionnel et non-linéaire du flux.Une comparaison de différentes techniques de pyrométries monochromatique,bichromatique et photothermique est effectuée sur une expérience de laboratoire de mesure detempérature. Une sensibilité importante de la technique de pyrométrie photothermique auxgradients de température sur la zone observée a été mise en évidence.Les dépôts en surface des composants exposés au plasma, sans inertie thermique, sontmodélisés par des champs de résistance thermique équivalente transverse. Ce champ derésistance est déterminé, en tout point de mesure, par confrontation du champ de températurede paroi issu de la thermographie avec le résultat d'une simulation par un modèlemonodimensionnel linéaire du composant. Une information sur la répartition spatiale du dépôtà la surface d'un composant est alors obtenue.Un calcul tridimensionnel et non-linéaire du champ de flux pariétal sur un composantest développé, par une méthode d'éléments finis, à partir de maillages de composants issus deCAO. La sensibilité du flux calculé à la précision des mesures de températures est discutée.Cette méthode est appliquée à des campagnes de mesures de températurebidimensionnelles par thermographie infrarouge sur des composants du tokamak JET. Leschamps de flux sur les tuiles du divertor, la protection supérieure et les protections poloïdalesinternes et externes sont déterminés et étudiés dans les deux directions, poloïdale ettoroïdale, du tokamak. La symétrie toroïdale du flux, d'une tuile à l'autre, est établie.L'influence de la résolution spatiale des mesures sur les flux calculés est discutée, à partir decomparaisons de résultats obtenus à partir de deux systèmes de thermographie de résolutionsdifférentes.
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49

Groz, Marie-Marthe. "Reconstruction 3D de sources de chaleur volumiques à partir des champs de température de surface mesurés par thermographie InfraRouge." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0135.

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L'évaluation et le contrôle non destructifs (E.C.N.D.) des matériaux et des structures sont une problématique industrielle très importante dans les domaines du transport, de l'aéronautique et du spatial, et dans le milieu médical. La thermographie infrarouge active est une technique d'E.C.N.D qui consiste à apporter une excitation extérieure afin d'entraîner une élévation de température dans le matériau, puis à évaluer le champ de température résultant à la surface. Cependant, les excitateurs thermiques utilisés (lampes flash, halogènes, lasers) agissent uniquement sur la surface du matériau. Plusieurs systèmes de conversion d'énergie peuvent en revanche mener à l'apparition de sources volumiques : on peut citer en particulier les phénomènes de thermo-acoustique, de thermo-induction, de thermomécanique ou de thermochimie. Par exemple, une excitation par ondes ultrasonores peut entraîner des sources thermiques volumiques si le matériau est viscoélastique ou s'il y a présence de défaut. La reconstruction de ces sources est donc la première étape permettant de remonter aux paramètres responsables de l'échauffement. Caractériser une source thermique consiste à reconstruire sa géométrie et la puissance qu'elle génère. Cependant, l'identification de sources thermiques volumiques par la mesure des champs de température de surface est un problème mathématiquement mal posé. Le caractère diffusif de la température en est le principal responsable. Dans ce travail, la reconstruction 3D des sources volumiques à partir du champ de température résultant à la surface, mesuré par InfraRouge, est étudié. Tout d'abord, une analyse du problème physique permet de spécifier les limites de la reconstruction. En particulier, un critère sur la résolution spatiale atteignable est défini et une limitation de reconstruction pour les sources en profondeur est mise en lumière. Ensuite, une méthode de reconstruction par approche probabiliste est proposée et comparée aux méthodes d'inversions existantes. Le temps d'exécution et la sensibilité au bruit de mesure sont étudiés pour chacune de ces méthodes. Des applications numériques et expérimentales seront enfin présentées pour illustrer les résultats
Non Destructive Testing (N.D.T.) of materials and structures is a very important industrial issue in the fields of transport, aeronautics and space and in the medical domain. Active infrared thermography is a N.D.T. method that consists in providing an external excitation to cause an elevation of temperature field in the material and then to evaluate the resulting temperature field at the surface. However, thermal exciters used (flash lamps, halogen, lasers) act only on the surface of the sample. Several energy conversion systems can on the other hand lead to the generation of volumetric sources: the phenomena of thermo-acoustic, thermo-induction, thermomechanic or thermochemistry can be cited. For example, ultrasonic waves can generate volumetric heat sources if the material is viscoelastic or if there is a defect. The reconstruction of these sources is the first step for the quantification of parameters responsible of the heating. Characterizing a heat source means reconstructing its geometry and the power it generates. For example, a defect in a structure and / or the viscoelasticity of a material can be detected and quantified by this technique if it acts directly on temperature field. However, identification of volumetric heat sources from surface temperature fields is a mathematical ill-posed problem. The diffusive nature of the temperature is the main cause. In this work, the 3D reconstruction of the volumetric heat sources from the resulting surface temperature field, measured by InfraRed, is studied. First, an analysis of the physical problem enables to specify the limits of the reconstruction. In particular, a criterion on achievable spatial resolution is defined and a reconstruction limitation for in-depth sources is highlighted. Then, a probabilistic approach for the reconstruction is proposed and compared to existing inverse methods. The computation time and noise sensitivity are studied for each of these methods. Numerical and experimental applications will thus be presented to illustrate the results
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Nebatti, Ech-Chergui Abdelkader [Verfasser], Burak [Akademischer Betreuer] Atakan, and Volker [Akademischer Betreuer] Buck. "Functional doped metal oxide films : [[Elektronische Ressource]] : Zinc oxide (ZnO) as transparent conducting oxide (TCO) Titanium dioxide (TiO2) as thermographic phosphor and protective coating / Abdelkader Nebatti Ech-Chergui. Gutachter: Volker Buck. Betreuer: Burak Atakan." Duisburg, 2011. http://d-nb.info/1015428088/34.

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