Dissertations / Theses on the topic 'Particle temperature measurement'
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Hopper, Richard. "Accurate temperature measurements on semiconductor devices." Thesis, De Montfort University, 2010. http://hdl.handle.net/2086/3315.
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Self-heating can have a detrimental effect on the performance and reliability of high power microwave devices. In this work, the thermal performance of the gallium arsenide (GaAs) Gunn diode was studied. Infrared (IR) thermal microscopy was used to measure the peak operating temperature of the graded-gap structured device. Temperature measurements were experimentally validated using micro-thermocouple probing and compared to values obtained from a standard 1D thermal resistance model. Thermal analysis of the conventionally structured Gunn diode was also undertaken using high resolution micro-Raman temperature profiling, IR thermal microscopy and electro/thermal finite element modeling. The accuracy of conventional IR temperature measurements, made on semiconductor devices, was investigated in detail. Significant temperature errors were shown to occur in IR temperature measurements made on IR transparent semiconductors layers and low emissivity/highly reflective metals. A new technique, employing spherical carbon microparticles, was developed to improve the measurement accuracy on such surfaces. The new ‘IR microparticle’ technique can be used with existing IR microscopes and potentially removes the need to coat a device with a high emissivity layer, which causes damage and heat spreading.
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Matthews, G. F. "The measurement of ion temperature in Tokamak Edge plasmas." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354847.
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Yi, Jihaeng. "Optical Sensors for High-Temperature Pressure Measurement and Real-Time Particle Detection." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/77229.
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In this thesis, we report the development of two types of optical sensors, one for high temperature pressure measurements and the other for real-time particle detection. With a high melting temperature (over 2000°C), low optical loss, and excellent corrosion resistance, sapphire (α-Al₂O₃) is ideal for high temperature sensing applications. Fabry-Perot (FP) cavity with optical interrogation of pressure response. The prototype is based on an extrinsic FP interferometer design and is constructed by combining reactive ion etching (RIE) with direct wafer bonding. Long-term testing proves that the adhesive-free wafer bond is sufficient to create a sealed Fabry-Perot cavity as a pressure transducer. Pressure measurement over a range of 6 to 200 psi has been demonstrated at room temperature using white-light interferometry.
For the other sensor, the goal is to detect the presence of micro- and nanoparticles in real time. The sensor is based on a silica fiber taper, and we aim to detect particle presence by measuring optical scattering and absorption induced by particles attached to the taper surface. To establish the relationship between particle density and optical transmission loss, we first consider a model where Au nanospheres are self-assembled on taper surface through electrostatic interaction. An analytical model is established to describe the adsorption of gold nanospheres onto cylindrical and spherical silica surfaces from quiescent aqueous particle suspensions. The curved surfaces of the fiber taper and microspheres are coated with nm-thick layer of a polycation, enabling irreversible adsorption of the negatively charged spheres. Our results fit well with theory, which predicts that the rates of particle adsorption will depend strongly on the surface geometry. In particular, adsorption is significantly faster on curved than on planar surfaces at times long enough that the particle diffusion length is large compared to the surface curvature. This is of particular importance for plasmonic sensors and other devices where particles are deposited from a suspension onto surfaces which may have non-trivial geometries.
We have established a theoretical model that can describe optical loss generated by particles on taper surface. This theory is validated by measuring, in real time, optical loss during the self-assembly of gold nanoparticles. We find that the measured optical loss can be quantitatively explained by the presence of multiple guided modes within the fiber taper region. Based on this work, we incorporate a fiber taper into a cascade impactor and show that welding aerosols attached to the fiber taper surface can induce measurable transmission loss during the welding process.Ph. D.
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Rongchai, Kanchit. "The High Temperature Condensation Particle Counter (HT-CPC) : a new instrument for a measurement of solid particulate matter." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708259.
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Takeyama, Mao. "Convective heat transfer of saturation nucleate boiling induced by single and multi-bubble dynamics." Kyoto University, 2021. http://hdl.handle.net/2433/261621.
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Martin, Michel. "Étude expérimentale de bolomètres rapides à jonctions tunnel métal normal-isolant-supraconducteur." Grenoble INPG, 1996. http://www.theses.fr/1996INPG0206.
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Nous etudions des bolometres bases sur des jonctions tunnel metal normal - isolant - supraconducteur en vue de leur application a la mesure d'energie d'ions retrodiffuses. La fabrication et l'etude de tels bolometres est montre en detail. On s'attache particulierement a l'influence des parametres physiques sur la mesure de temperature.
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Potier, Bruno. "Détermination des champs des températures et des concentrations dans une flamme de charbon pulvérisé de taille semi-industrielle : application au four pilote 1 mw du cerchar." Orléans, 1986. http://www.theses.fr/1986ORLE0012.
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Développement d'une méthode optique de mesure des températures, basée sur l'émission et l'absorption du rayonnement thermique dans le proche infrarouge, et permettant de déterminer la température en un point. Parallèlement aux champs des températures cette méthode permet d'accéder aux champs de concentrations relatives en particules et en dioxyde de carbone et fournir des renseignements sur les valeurs in situ de plusieurs paramètres nécessaires à la modélisation des transferts thermiques.
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Tobiasson, John Robert. "Determining H2O Vapor Temperature and Concentration in Particle-Free and Particle-Laden Combustion Flows Using Spectral Line Emission Measurements." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6497.
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There is a growing need for the clean generation of electricity in the world, and increased efficiency is one way to achieve cleaner generation. Increased efficiency may be achieved through an improved understanding of the heat flux of participating media in combustion environments. Real-time in-situ optical measurements of gas temperature and concentrations in combustion environments is needed. Optical methods do not disturb the flow characteristics and are not subject to the temperature limitation of current methods. Simpler, less-costly optical measurements than current methods would increase the ability to apply them in more circumstances. This work explores the ability to simultaneously measure gas temperature and H2O concentration via integrated spectral intensity ratios in regions where H2O is the dominant participating gas. This work considered combustion flows with and without fuel and soot particles, and is an extension of work previously performed by Ellis et al. [1]. Five different combustion regimes were used to investigate the robustness of the infrared intensity integral method first presented by Ellis et al. [1]. These included Post-Flame Natural Gas (PFNG), Post-Flame Medium Wood (PFMW), Post-Flame Fine Wood (PFFW), In-Flame Natural Gas (IFNG), and In-Flame Fine Wood (IFFW). Optical spectra were collected as a function of path length for each regime. Methods for processing the spectra to obtain gas temperature, gas concentration, broadband temperature, and broadband emissivity were developed. A one-dimensional spectral intensity model that allowed for specular reflection, and investigated differences between measured and modeled spectral intensities was created. It was concluded that excellent agreement (within 2.5%) was achieved between optical and suction pyrometer gas temperatures as long as 1) the optical probe and cold target used were well-aligned 2) the path length was greater than 0.3 m and 3) the intensity from broadband emitters within the path was smaller than the gas intensity. Shorter path lengths between 0.15 – 0.3 m produced reasonable temperatures with 7 % error while path lengths of 0.05 m or less were as much as 15% in error or the signal would not effectively process. Water vapor concentration was less accurate being at best within 20% (relative) of expected values. The accurate determination of concentration requires first an accurate temperature concentration as well low broadband participation. Some optical concentrations were in error as much as 85%. The 1-D model was compared to the measurement and it was found that the model peaks were sharper and shifted 0.167 cm-1 compared to the measured data. The reason for the shift can be attributed to the uncertainty of the reference laser frequency used in the FTIR. No conclusion was found for the cause of the sharper peaks in the model. The integrated area of bands used to find temperature and concentration matched well between the model and measured spectrum being typically within 3%.
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Hayakawa, N., M. Nagino, H. Kojima, M. Goto, T. Takahashi, K. Yasuda, and H. Okubo. "Dielectric characteristics of HTS cables based on partial discharge measurement." IEEE, 2005. http://hdl.handle.net/2237/6772.
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Idris, Mahmoud [Verfasser]. "Two-Colour Pyrometer Technique for Coal-Particle Temperature Measurements in a Pulverised Coal Flame / Mahmoud Idris." Aachen : Shaker, 2004. http://d-nb.info/1181603501/34.
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Nastic, Aleksandra. "Cold Gas Dynamic Spray Impact: Metallic Bonding Pre-Requisites and Experimental Particle In-Flight Temperature Measurements." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42086.
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The impact phenomena of high velocity micron-size particles, although commonly considered and described as detrimental in numerous engineering applications, can be used in a beneficial way if properly understood and controlled. The Cold Gas Dynamic Spray (CGDS) process, known as a surface modification, repair and additive manufacturing process, relies on such high velocity impacts. In the process, solid particles are accelerated by a supersonic gas flow to velocities up to 1200 m/s and are simultaneously heated to temperatures lower than their melting point. When propelled under proper velocity and temperature, the particles can bond onto a target surface. This bonding is caused by the resulting interfacial deformation processes occurring at the contact interface. Hence, the process relies heavily on the gas/particle and particle/substrate interactions.
Although numerous experimental and/or numerical studies have been performed to describe the phenomena occurring during particle flight and impact in the CGDS process, numerous phenomena remain poorly understood. First, the effect of substrate surface topographical condition on the particle deformation and ability to successfully adhere, i.e. atomically and/or mechanically, has not been thoroughly investigated such that its influence is not well understood. Another aspect of the process that is generating the largest gap between experimental and numerical studies in the field is the lack of particle in-flight temperature measurements. Obtaining such data has proven to be technically difficult. The challenges stem from the short particle flight time, low particle temperature and small particle size preventing the use of established thermal spray pyrometry equipment. Relatedly, lack of such measurements precludes a proper experimental study of the impact related phenomena at the particle/substrate interface. As a result, the effect of particle size dependent temperature on overall coating properties and atomic bonding relies currently on estimates. Finally, the effect of particle impact characteristics on interfacial phenomena, i.e. grain size and geometry, velocity/temperature, and oxide scale thickness, on adhesion and deformation upon single particle collision has also been scarcely studied for soft particle depositions on hard substrate.
Hence, the current research work aims at studying fundamental aspects of particle/gas heat transfer and particle/substrate impact features in goals to improve the understanding of the CGDS process. Different surface preparation methods will be used to create various surface roughness and topographical features, to provide a clear understanding of the target surface state influence on coating formation and adhesion. Additionally, new equipment relying on novel technology, i.e. high-speed IR camera, will be utilized to obtain particle in-flight temperature readings with sequence recordings. Subsequently, the experimental particle in-flight temperature readings will be used to develop a computational fluid dynamics model in goals to validate currently used Nusselt number correlations and heat transfer equations. The particle size-dependent temperature effect on the particle’s elastic and plastic response to its impact with a targeted surface and its ability to successfully bond and form a coating will be studied experimentally. A thorough CFD numerical work, based on experimental findings, will be included to provide full impact characteristics (velocity, temperature, size and trajectory) of successfully deposited particles. Finally, the numerical results will be utilized in the ensuing study to correlate single particle deformation, adhesion and interfacial features to impact characteristics. A finite element model will be included to investigate the effect of particle size dependent temperature on single particle interfacial pressure, temperature and bonding ability.
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Nasri, Ridha. "Conception et réalisation d'un adaptateur haute impédance programmable : epplication à la caractérisation de liquides magnétiques." Saint-Etienne, 1994. http://www.theses.fr/1994STET4014.
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Ce travail s'inscrit dans le cadre de la recherche sur les ferrofluides ou liquides magnétiques. Les évolutions, qui peuvent être rapides, des propriétés diélectriques de ces matériaux telles que les changements de phase du liquide porteur, la perte d'homogénéité par formation d'agrégats ou de multicouches nécessitent l'automatisation complète de l'acquisition des mesures. Pour cela, nous avons développé autour d'un analyseur vectoriel, un adaptateur haute impédance programmable en mode shunt fonctionnant dans la gamme 1mhz-10khz. Cette réalisation fait appel à l'électronique haute impédance : résistances de fortes valeurs allant jusqu'à iteraohm et condensateurs à faibles fuites ; ces composants sont commutés par des relais de résistance d'isolement supérieure à 1000teraohms commandes par le bus VXI. Ce spectromètre automatique nous a permis de caractériser, entre 50c et -200c, un ferrofluide ionique composé de particules nanométriques de ferrite de manganèse (Fe2Mno4) dispersées dans le tétrachlorure de carbone (CCL4) utilisé comme liquide porteur. Nous avons ainsi mis en évidence les différentes phases du tétrachlorure de carbone pur à pression atmosphérique (liquide, plastique, solide). Les résultats obtenus sur le ferrofluide, à plusieurs concentrations, ont été analysés selon diverses lois de mélanges théoriques utilisant les constantes diélectriques des deux constituants. Nous avons pu montrer, dans nos conditions expérimentales, la perte de stabilité de ce ferrofluide à basse température et forte concentration
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Shrestha, Kristina. "Time-Resolved Temperature Measurements and Thermal Imaging using Nano-Thermometers in Different Environments." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1593706274306985.
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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 moteurA 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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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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Henkel, Marion [Verfasser]. "Measurements of ion temperatures and fast particles in the scrape-off layer of W7-X stellarator and EAST tokamak / Marion Henkel." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2021. http://d-nb.info/1239413556/34.
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Vogt, Jan [Verfasser], Peter [Akademischer Betreuer] Stephan, and Cameron [Akademischer Betreuer] Tropea. "Development of novel Particle Image Thermometry methods for highly resolved measurements of temperature and velocity fields in fluids / Jan Vogt. Betreuer: Peter Stephan ; Cameron Tropea." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2014. http://d-nb.info/1108093736/34.
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Segura, Rodrigo [Verfasser]. "Thermo-Liquid Crystal (TLC) Thermography and Astigmatism Particle Tracking Velocimetry (APTV) for the simultaneous time-resolved 3D measurements of microscopic temperature and velocity flow fields / Rodrigo Segura." Aachen : Shaker, 2014. http://d-nb.info/1066197202/34.
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Adepu, Rasagna. "Reliability of Interfaces for HVDC Cable Accessories." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21026/.
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HVDC cable systems are widely used in modern transmission networks. This project investigates the dielectric withstand properties of the interfaces existing in the accessories (joints, termination). Interfaces are a weak point as cavities exist at the contact between the cable and the accessory body. Interfaces have been studied as the mating of two elastic surfaces using elastic-plastic mechanics. Their withstand properties are greatly improved by using rubbery material (e.g., silicon rubber) and oiling the surfaces as the number and size of the cavities is reduced. However, thermal aging of the surfaces (with loss of elasticity) and the migration of the lubricant might lead to conditions where the interfaces are again the weak link of the system.
The goal of this thesis is to understand breakdown mechanisms of XLPE/XLPE and XLPE/LDPE interfaces through the analysis of partial discharges, space charge accumulation and leakage current measurement. Space charge is measured through the Thermal Step and the Pulsed Electro-Acoustic methods (TSM and PEA). TSM highlights that there exists a critical voltage at which the space charge shifts from homo- to hetero-charge.
The conductivity characteristics of the XLPE insulation of HVDC cable are investigated under different applied mechanical stress and the breakdown voltage which could be affected by crosslinking byproducts within the insulation of the material.
Partial Discharge is a key tool to ensure the reliability and life extension of High Voltage electrical equipment. For cable interfaces, it is generally assumed that surface partial discharges create carbonized tracks at the contact between the cable insulation and the accessory body leading to breakdown. In this thesis, it was not possible to reproduce this condition. Breakdown occurred through a mechanism that remains to be unraveled. A possible connection with the shifts mentioned above, from homo to hetero charge at the interface, seems to exist.
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Segura, Rodrigo [Verfasser], Christian J. [Mitwirkender] [Akademischer Betreuer] Kähler, and Michael [Akademischer Betreuer] Schlüter. "Thermo-Liquid Crystal (TLC) Thermography and Astigmatism Particle Tracking Velocimetry (APTV) for the simultaneous time-resolved 3D measurements of microscopic temperature and velocity flow fields / Rodrigo Segura. Universität der Bundeswehr München, Fakultät für Luft- und Raumfahrttechnik. Bearb.: Christian J. Kähler. Gutachter: Christian J. Kähler ; Michael Schlüter." Neubiberg : Universitätsbibliothek der Universität der Bundeswehr München, 2014. http://d-nb.info/1069125040/34.
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Segura, Rodrigo [Verfasser], Christian J. [Mitwirkender] Kähler, and Michael [Akademischer Betreuer] Schlüter. "Thermo-Liquid Crystal (TLC) Thermography and Astigmatism Particle Tracking Velocimetry (APTV) for the simultaneous time-resolved 3D measurements of microscopic temperature and velocity flow fields / Rodrigo Segura. Universität der Bundeswehr München, Fakultät für Luft- und Raumfahrttechnik. Bearb.: Christian J. Kähler. Gutachter: Christian J. Kähler ; Michael Schlüter." Neubiberg : Universitätsbibliothek der Universität der Bundeswehr München, 2014. http://nbn-resolving.de/urn:nbn:de:bvb:706-4151.
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Belleoud, Pierre. "Etude de la convection naturelle turbulente en cavité verticale différentiellement chauffée : Analyse des structures et des transferts turbulents." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2016. http://www.theses.fr/2016ESMA0005/document.
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Les écoulements de convection naturelle en espace confiné sont généralement turbulents (grandes dimensions et/ou écarts de température importants). L'approfondissement de la connaissance de ce régime et des transferts qui y sont associés semble donc essentielle. Cette étude expérimentale concerne les mécanismes de transferts thermiques turbulents en s'appuyant sur des mesures couplées vitesse/température dans un écoulement de convection naturelle turbulente à haut nombre de Rayleigh (Ra1-1= 1,2x1011) au sein d'une cavité différentiellement chauffée de rapport de forme vertical (hauteur/largeur) égale à 4. Une chaîne de mesure PIV permet les acquisitions de vitesse tandis que la température est mesurée par micro-thermocouple de type K (0=12,7 μm). Les deux mesures étant synchronisées via un générateur de pulses type BNC®. Une attention particulière a été portée à la détermination des conditions aux limites en température des parois adiabatiques et au post traitement des données de PIV à l'aide d'une décomposition orthogonale basée sur l'énergie cinétique des champs de vitesse (POD). Cela a rendu possible, d'une part le calcul expérimental de quantités liées à la turbulence comme les flux d'enthalpie et des nombres adimensionnés pour la turbulence (Prandtl, diffusivité ... ) et, d 'autre part, l'évaluation de la contribution des autres termes des équations de Navier-Stokes (gradient de pression et terme source volumique). Enfin, une discussion sur les échelles caractéristiques de l'écoulement est menée et une comparaison avec des résultats de simulations numériques est apportéeNatural convection flows in confined spaces are often turbulent (large dimensions and/or temperature difference ). Improving the knowledge of this type of regime and of the associated heat and mass transfers seems, therefore, to be essential. This experirnental work studies heat transfer mechanisms using coupled and synchronized measurernents of temperature and velocity in a turbulent natural convection flow at high Rayleigh number (Ra1-1=I.2 x1011) in a differentially heated cavity with a vertical aspect ratio (height/width) of 4. Velocity measurernents are acquired by PIV and temperature is measured with K-type micro-thermocouple (0=12.7 μm). Both measurementsystems are synchronized using a BNC® pulse generator. Thermal boundary conditions of the adiabatic walls and post treatment of PIV data using an orthogonal decomposition based on the kinetic energy of the flow - POD - have been considered with caution. It makes possible, on the one hand, the experimental assessment of turbulent quantities like enthalpy fluxes and dimensionless nurnber (Prandtl, diffusivity ... ) and, on the other hand the estimation of the contribution of the other terms of Navier-Stokes equations (pressure gradient and source term). Finally a discussion on characteristic scales of the flow and a comparison with numerical simulations are provided
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Brahme, Upendra. "Two-color pyrometer temperature profiles for single particle graphite combustion." 1986. http://hdl.handle.net/2097/27597.
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Lewis, Elliott William. "Development and Application of a Method for Gas-phase Temperature Measurements in Particle-laden Flows." Thesis, 2022. https://hdl.handle.net/2440/136045.
Full textAbstract:
Suspensions of particles in a carrier flow of gas are utilised in, or being
developed for, several high-temperature industrial processes. These include
for material transformations in calciners and kilns, as fuel in particulate
burners and as the medium for radiation absorption in concentrated solar
thermal receivers. The efficiency, stability, and emissions from such systems
is strongly dependent on the temperature distribution of both the particle
and fluid phases, each of which can be highly variable both spatially and
temporally. While these systems are widely utilised, there is still a lack of
fundamental understanding of the heat transfer processes due to the complexity
of turbulent particle-laden flows with a high particle volume fraction.
Therefore, this work aims to provide insight into these processes for future
optimisation of non-isothermal particle-based systems. This is performed by
adapting and applying the technique of laser induced fluorescence (LIF) to
measure the gas-phase temperature in a particle-laden flow that is heated
using high-flux radiation.
This thesis presents the first demonstration of LIF in the densely loaded
conditions present in particle-laden flows relevant to industrial application,
with the potential for strong optical interference from elastic scattering of
radiation from the excitation laser by particles. The two-colour method for
thermometry, with toluene as the fluorescent tracer, was used to provide
spatially resolved measurements from a < 1 mm thick planar cross-section
of the flow. The particle distribution was measured simultaneously with
the temperature by imaging the laser light scattered by particles (particle
nephelometry). The accuracy and precision of the two-colour LIF method
was assessed for a series of particle materials and diameters, including
materials that luminesce following absorption of the excitation laser light. The
results show that optical filters effectively suppress the detection of elastically
scattered light, with other sources of measurement uncertainty including
particle luminescence, laser attenuation, and signal trapping identified and
assessed. The systematic error in the measurement from these combined sources was shown to increase with local particle loading, but be independent
of particle diameter.
The two-colour LIF and particle nephelometry methods were applied to
simultaneously measure the gas-phase temperature and particle distributions
in a particle-laden flow heated using high-flux radiation, evaluated for systematically
varied series of particle diameter, particle volumetric loading, and
heating power. The measurements were recorded in a particle-laden jet flow
issuing from a long, straight pipe with well-defined inlet and co-flow conditions,
with the particles heated using an axisymmetric, well-characterised
infra-red radiative source generating a beam with a peak flux of up to 42.8
MW/m2 on the axis. The resulting gas-phase temperature profile increased
monotonically with distance down-stream from the start of the heating region,
at up to 2,200 ◦C/m on the jet centreline. Additionally, attenuation of
the heating beam was shown to lead to an asymmetric temperature profile in
the jet flow.
The rate of increase of the gas temperature was shown to be directly
proportional to both the heating flux and the time-averaged particle volumetric
loading, within the range of conditions investigated. The temperature
decreased significantly with an increase in particle diameter, due to the
dependence of radiative and convective heat transfer processes to different
exponents of the diameter. The experimental results for the temperature rise
on the jet centreline were shown to match the trends from a simplified analytical
model. Importantly, the model also predicts that the particle temperature
is significantly greater than the gas, from the heating region to the edge of the
measurement region investigated. The asymmetry of the flow temperature
due to attenuation of the heating beam is also shown to increase with an
increase in the particle loading and a decrease in the particle diameter (i.e.,
an increase in the total cross-sectional area of particles in the flow).
The instantaneous distributions of both the gas-phase temperature and
particle locations were demonstrated to be highly non-uniform in the radiatively
heated particle-laden flow. The particle distributions were analysed
using Voronoi diagrams to determine the locations of particle clusters. Void
regions (i.e., with no nearby particles) were also identified. The gas-phase
temperature around particles was shown to be dependent on the local particle
loading, with the measured temperature inside of clusters also greater than
that outside of clusters. Localised regions of relatively high or low temperature
compared to their surroundings were also identified from the instantaneous
images, with these regions shown to remain coherent to the downstream
edge of the measurement region. The high temperature regions are
shown to be typically associated with regions of high local particle-loading, while regions with low temperature are shown to be in the void regions or
with a low particle loading. These results suggest that the structures in the
flow are long-lived with a sufficient particle-gas temperature difference, both
within the heating region and in the near-field downstream, for convection
between the particles and gas to influence the gas-phase temperature field
more significantly than entrainment, mixing, and convection within the gas
flows.Thesis (Ph.D.) -- University of Adelaide, School of Mechanical Engineering, 2022
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"Heat Transfer in a Rotary Drum Using Infrared Camera Temperature Measurement." Master's thesis, 2019. http://hdl.handle.net/2286/R.I.53613.
Full textAbstract:
abstract: Rotary drums are commonly used for their high heat and mass transfer rates in the manufacture of cement, pharmaceuticals, food, and other particulate products. These processes are difficult to model because the particulate behavior is governed by the process conditions such as particle size, particle size distribution, shape, composition, and operating parameters, such as fill level and rotation rate. More research on heat transfer in rotary drums will increase operating efficiency, leading to significant energy savings on a global scale.
This research utilizes infrared imaging to investigate the effects of fill level and rotation rate on the particle bed hydrodynamics and the average wall-particle heat transfer coefficient. 3 mm silica beads and a stainless steel rotary drum with a diameter of 6 in and a length of 3 in were used at fill levels of 10 %, 17.5 %, and 25 %, and rotation rates of 2 rpm, 6 rpm, and 10 rpm. Two full factorial designs of experiments were completed to understand the effects of these factors in the presence of conduction only (Case 1) and conduction with forced convection (Case 2). Particle-particle friction caused the particle bed to stagnate at elevated temperatures in Case 1, while the inlet air velocity in Case 2 dominated the particle friction effects to maintain the flow profile. The maximum heat transfer coefficient was achieved at a high rotation rate and low fill level in Case 1, and at a high rotation rate and high fill level in Case 2. Heat losses from the system were dominated by natural convection between the hot air in the drum and the external surroundings.Dissertation/Thesis
Masters Thesis Chemical Engineering 2019
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Kueh, Kimberley C. Y. "Development and Application of Methods to Measure Temperatures of Flowing Particles in Suspension." Thesis, 2019. http://hdl.handle.net/2440/123626.
Full textAbstract:
This thesis reports on the development and application of a new method for the measurement of particles transported within a moving fluid and subjected to high fluxes of radiant heating. The comprehensive understanding of heat transfer in particle-laden flows is important as it is a key factor in enabling optimisation of various industrial and scientific applications such as combustion, mineral processing plants, and pharmaceutical manufacturing, as well as aid in the development of new technologies based on the two-phase flow. However, one of the major factors that limits the furtherance of understanding of the field is the difficulty in measuring temperatures of moving, micron-sized particles. Previously, most publications on heat transfer in particle-laden flows focus on gas temperature measurements, where the temperatures of particles are inferred through fundamental heat transfer equations. However, this technique is not applicable in systems where a large disparity exist between the gas and particle temperatures, and does not take into account inter-particle relationships which could have a significant effect on the overall heat transfer where the interparticle spacing is sufficiently low. In order to distinguish between the particle and gas phase temperatures, a radiative heat source capable of delivering continuous heat fluxes of up to 36.6MW/m2 in the form of a Solid-State Solar Thermal Simulator (SSSTS) was used throughout this dissertation. This is because the SSSTS operates at a wavelength of 910nm, which is only absorbed by the particle phase and not the gas phase. Importantly, the operation of the SSSTS at this wavelength does not interfere with the excitation signal (355nm) used in the LIP technique. However, the performance of the SSSTS is not well understood due to the system being the first of its kind. Chapter 4 of this dissertation addresses this by characterising in detail the SSSSTS. The next part of this dissertation describes the development and application of single-shot, nonintrusive particle temperature measurement techniques based on laser-induced phosphorescence (LIP), a thermometry that makes use of the phosphorescent emission properties of thermophosphors (TPs) governed by the temperature-dependent Boltzmann distribution. Here, ZnO:Zn TPs were selected to be used as they have the highest temperature sensitivity below 625°C. The TPs were suspended in unsteady flow in an optically-accessible fluidised bed and subjected to high radiative heat fluxes of up to 21.1 MW/m2. Two types of thermometry are reported – with Chapter 5 describing the development of an in-situ, areaaveraged, temporally-resolved particle temperature measurement technique by analysing the change in phosphorescent emission spectra of the selected TP with respect to wavelength, collected using a fibre-optic cable connected to a spectrometer; and Chapter 6 detailing a single-shot, planar particle temperature measurement. For the planar thermometry, the phosphorescent emissions of the TPs were collected using a single ICCD camera fitted with an image splitter and two interference filters specifically selected. Each measurement derives from two 15mm × 10.8mm images collected simultaneously to avoid errors associated with timedelays and/or angular distortions. The resultant spatial resolution for each image was 51pixels/mm, with an average of 30 particles recorded within the imaging region. It was demonstrated that the particle temperatures measured with the LIP technique was found to be approximately 44°C higher on average than the gas temperatures measured with a thermocouple in the same system. A strong dependence of heat flux, as well as particle attenuation (mass loading) on particle temperature was also reported. Additionally, a maximum particle temperature rise of 350°C was recorded with a heat flux of 21.1 MW/m2, where the maximum particle residence time in the heating region is 0.05s. The next section of this thesis details the study of application of the developed thermometry technique in a laminar particle-laden jet flow issued from a 12.8mm pipe downwards into a wind tunnel and the particles radiatively heated by the SSSTS. The measured data were analysed by comparison with the results from a simple first-order analytical model that considers the radiative heating, convective cooling, radiative heat loss and heat gain of a single particle. It was found that heat flux, particle concentration and to a lesser extent, particle diameter all affect particle temperatures. At low heat fluxes, 𝑄̇𝑟𝑎𝑑 ≤ 6.1 MW/m2, particle concentrations and temperatures were found to be higher in jet edge, consistent with previous investigations. At heat fluxes above that, where 𝑄̇𝑟𝑎𝑑 > 6.1 MW/m2, thermophoresis was observed, as evidenced by the migration of the smaller particles to the jet edge where the local temperature is lower. The effect of buoyancy was also observed at 𝑄̇𝑟𝑎𝑑 ≥ 20.6 MW/m2, as evidenced by two distinct regions of high particle temperatures upstream from the heating region (one at the jet axis, and one at the jet edge). These results were presented in Chapter 7 of the present dissertation.Thesis (Ph.D.) -- University of Adelaide, School of Mechanical Engineering, 2020
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Rickelmann, Mary Ann. "Comparison of core and rectal temperature measurements a research report submitted in partial fulfillment ... medical-surgical nursing /." 1989. http://catalog.hathitrust.org/api/volumes/oclc/68788469.html.
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Taylor, Craig J., Laura E. Dieker, Kelly T. Miller, Carolyn A. Koh, and E. Dendy Sloan. "HYDRATE PARTICLES ADHESION FORCE MEASUREMENTS: EFFECTS OF TEMPERATURE, LOW DOSAGE INHIBITORS, AND INTERFACIAL ENERGY." 2008. http://hdl.handle.net/2429/1138.
Full textAbstract:
Micromechanical adhesion force measurements were performed on tetrahydrofuran (THF) hydrate particles in n-decane. The experiments were performed at atmospheric pressure over the temperature range 261–275 K. A scoping study characterized the effects of temperature, anti-agglomerants, and interfacial energy on the particle adhesion forces. The adhesion force between hydrate particles was found to increase with temperature and the interfacial energy of the surrounding liquid. The adhesion force of hydrates was directly proportional to the contact time and contact force. Both sorbitan monolaurate (Span20) and poly-N-vinyl caprolactam (PVCap) decreased the adhesion force between the hydrate particles. The measured forces and trends were explained by a capillary bridge between the particles.
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Meyers, Bronwyn Clara. "The experimental flowfield and thermal measurements in an experimental can-type gas turbine combustor." Diss., 2010. http://hdl.handle.net/2263/27538.
Full textAbstract:
In this study, experimental data was collected in order to create a test case that can be used to validate computational fluid dynamics (CFD) simulations and the individual models used therein for gas turbine combustor applications. In many cases, the CFD results of gas turbine combustors do not correlate well with experimental results. For this reason, there is a requirement to test the simulation method used before CFD can successfully be used for combustor design. This test case encompasses all the features of a gas turbine combustor such as a swirler, primary, secondary and dilution holes as well as cooling rings. Experiments were performed on the same combustor geometry for both non-reacting and reacting flows. The non-reacting flow experiments consisted of stereoscopic particle image velocimetry (PIV) measurements performed at various planes in the three zones of the combustor. Data was collected on planes, both in line with the holes and in between the holes of each zone. For the reacting experiments, the temperatures on the outlet plane were measured using a thermocouple rake, thus a temperature contour plot on the outlet plane was produced. Further, the combustor can was modified with passive inserts, which were tested to determine their influence on the outlet temperature distribution during reacting runs. In this set-up, the outlet velocity profiles were also measured using a Pitot tube during both non-reacting and reacting flows. In addition to the outlet temperature distribution and velocity profiles, images of the flame patterns were captured, which showed the positions of flame tongues, fluctuating flames and steady flames. Carbon burn patterns on the walls of the combustor liner were also captured. From the data collected during the reacting runs, the pattern factor, profile factor, overall pressure loss and pressure loss factor were calculated. The non-reacting experiments performed using the PIV, produced three-dimensional velocity vector fields throughout the combustor. These experiments were performed at various flow rates, which gave an indication of which features of the combustor flow were affected by the flow rate. When comparing the individual PIV images alongside one another, the temporal nature of the combustor flow was also evident. The reacting experiments revealed a hot region of exhaust gas around the outer edge of the exhaust while there was a cooler region in the centre of the outlet flow. The PIV flowfield results revealed the reason for then hot outer ring-like region was due to the path the hot gasses would take. The hot combustor gas from the primary zone diverges outwards in the secondary zone then is further forced to the outside by the dilution recirculation zone. The hot flow then leaves the combustor along the wall while the cooler air from the jets leaves the combustor in the centre. The experiments performed produced a large variety of data that can be used to validate a number of aspects of combustor simulation using CFD. The non-reacting experimental data can be used to validate the turbulence models used and to evaluate how well the flow features were modelled or captured during the non-reacting stage of the combustor simulation process. The typical flow features such as jet penetration depths and the position and size of the recirculation regions are provided for effective comparison. The thermal results presented on the outlet plane of the combustor can be used for comparison with CFD results once combustion is modelled. CopyrightDissertation (MEng)--University of Pretoria, 2010.
Mechanical and Aeronautical Engineering
unrestricted
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Vogt, Jan. "Development of novel Particle Image Thermometry methods for highly resolved measurements of temperature and velocity fields in fluids." Phd thesis, 2014. https://tuprints.ulb.tu-darmstadt.de/3696/7/2014_01_08_Dissertation_Vogt.pdf.
Full textAbstract:
The subject of present thesis is the development of a technique for simultaneous measurement of temperature and velocity fields in liquids based on the luminescence of particles. This technique is intended to be used for the experimental investigation of transient phase change phenomena like nucleate boiling that takes place on a small spatial scale. For that reason, the main requirement for the developed technique is the ability for temporally and spatially highly resolving measurements. Existing methods either do not offer such high resolution or do not facilitate simultaneous temperature and velocity measurements.
Two different approaches for particle-based temperature measurements are presented, one using microcapsules with a temperature-sensitive dye solution in the core and the other using particles fabricated
from dyed polymers. The developed microcapsules have a fluorescence characteristic that enables the implementation of a 2-colour-LIF procedure. Fluorescence is excited using a laser with a wavelength
of 532 nm and the resulting signals (temperature-sensitive signal and reference signal) are detected by two separate high-speed cameras with appropriate filters. While the brightness of the particles in the images of both cameras serves as temperature indicator, velocity information is extracted from subsequent images of a single camera by means of the PIV method. The applicability of this technique for highly resolved measurements is shown for light-sheet and volume illumination. Therefore, experimental results from a stationary flow driven by natural convection and a flow through a capillary tube driven by a pressure difference are compared to the respective numerical solution of these flows. Moreover, the technique is characterized with regard to accuracy and possible sources of error.
The dyed polymers on the contrary, are only investigated with regard to their general applicability for temperature measurements.
Laser induced fluorescence with dyes dissolved in acetone is used to measure the temperature field around a growing vapour bubble and the suitability of optical methods for this future application is
analyzed.
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Stewart, Mairi. "Non-invasive measurement of stress and pain in cattle using infrared thermography : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science at Massey University, Palmerston North, New Zealand." 2008. http://hdl.handle.net/10179/750.
Full textAbstract:
The aim of this thesis was to validate the use of infrared thermography (IRT) to non-invasively measure stress and/or pain in cattle. The main approach was to measure changes in heat emitted from superficial capillaries around the eye (referred to as eye temperature) in response to various aversive husbandry procedures used routinely on farms. In addition, various exogenous challenges were given to investigate the role of the hypothalamic-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS) in regulating the eye temperature response. No evidence was found to support the hypothesis that an increase in eye temperature was due to HPA activity in cattle. A rapid drop in eye temperature occurred immediately after disbudding, an electric prod, startling and shouting. It is suggested that this was caused by the redirection of blood from the capillary beds via sympathetically-mediated vasoconstriction. Therefore, the role of the ANS was tested by measuring eye temperature, heart rate variability (HRV) and plasma catecholamine responses simultaneously. Somatic pain from disbudding and initial responses to surgical castration included a synchronised drop in eye temperature, increases in catecholamines and changes in HRV indicative of increased sympathetic activity. The role of the sympathetic nervous system was further confirmed by a drop in eye temperature that occurred following an epinephrine challenge. In contrast, deeper visceral pain from castration caused a more marked increase in eye temperature and changes in HRV indicative of increased parasympathetic tone. The underlying mechanism driving the increase in eye temperature is unknown; however, it is possible that it may be caused by vasodilation due to increased parasympathetic activity. These differences in ANS responses to different procedures, detected by IRT and HRV, may be due to the nature of the pain and the relative fear associated with the procedure. In summary, this research showed that during stress or pain, the heat emitted from superficial capillaries around the eye changes as blood flow is regulated under ANS control and these changes can be quantified using IRT. A combination of IRT and HRV is a non-invasive way to measure ANS activity and assess acute welfare impacts of husbandry practices in cattle. Further research using pharmacological inhibition and stimulation of the ANS activity would be beneficial to fully understand the underlying regulatory mechanisms of the eye temperature and HRV responses in cattle and other species during stress and/or pain. The full capability of IRT and HRV for detection of disease and emotional states and the effects of different intensities of pain, individual traits and previous experience also deserve attention.