Dissertations / Theses: 'Temperature measurents'

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Jacobi, Christoph, and Dierk Kürschner. "Mesopause region temperatures and plasma scale height estimations from VHF meteor radar and LF absolute reflection height measurements at Collm." Universitätsbibliothek Leipzig, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-219583.

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The change of ionospheric absolute reflection heights h of low-frequency (LF) radio waves at oblique incidence in the course of the day is measured at Collm Observatory (51.3°N, 13.0°E) using 1.8 kHz sideband phase comparisons between the sky-wave and the ground wave of a commercial 177 kHz transmitter (Zehlendorf, reflection point 52.1°N, 13.2°E). Plasma scale height estimates H are calculated from the decrease/increase of h in the morning/evening. The day-to-day variations of H are compared with those of daily mean temperatures at 90 km, measured with a VHF meteor radar (36.2 MHz) at Collm utilising the amplitude decay of meteor reflections. A good qualitative correspondence is found between the two data sets. Since mesospheric long-period temperature variations are generally accepted to be the signature of atmospheric planetary waves, this shows that LF reflection height measurements can be used for monitoring the dynamics of the upper middle atmosphere.

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2

Wolf, Kevin, André Ehrlich, and Manfred Wendisch. "Temperature profiles from airborne pyrgeometer measurements of broadband terrestrial radiation." Universität Leipzig, 2016. https://ul.qucosa.de/id/qucosa%3A16702.

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Profiles of broadband terrestrial radiation from airborne pyrgeometer measurements aboard research aircraft Polar 5 obtained during the VERDI campaign in 2012 were used to derive vertical temperature profiles. The retrievals were performed utilizing radiative transfer simulations by libRadtran (Mayer and Kylling, 2005). Manually changing the temperature of the input file for the simulations resulting calculated profiles of terrestrial irradiance were compared with measured profiles and iterated until best agreement. The selected test case shows the possibility of this technique and reveals several possible improvements. The algorithm has to be optimized to adapt the modelling temperature profile automatically using least-square error minimization between measured and modelled irradiance profiles. Additionally the vertical resolution has to be increased to consider small-scale variations. Using humidity and pressure profiles from ground-based observations and nearby radiosoundings significantly improves the retrieved temperature profiles.
Vertikalprofile der breitbandigen terrestrischen Strahlung von flugzeuggetragenen Pyrgeometermessungen an Bord des Forschungsflugzeuges Polar 5 während der VERDI Kampagne in 2012 wurden genutzt, um Vertikalprofile der Temperatur abzuleiten. Das Retrieval erfolgte mit Hilfe von Strahlungstransfersimulationen unter der Verwendungung von libRadtran (Mayer and Kylling, 2005). Dazu wurde die Temperatur der Modellatmosphäre variert, bis eine bestmögliche Übereinstimmung von gemessenem und modellierten Irradianzprofil erzielt wurde. Der ausgesuchte Testfall zeigt das Potential dieser Technik und mögliche Verbessungsansätze. So muss der verwendete Algorithmus automatisiert werden, indem das modellierte Strahlungsprofil mit Hilfe eines Iterationsverfahrens und der Methode der kleinsten Fehlerquadrate an das gemessene Profil angepasst wird. Zusätzlich ist eine Erhöhung der vertikalen Auflösung von 50 m auf 10 m Schritte nötig, um kleinskalige Fluktuationen zu berücksichtigen. Die Verwendung von bodengebundenen Beobachtungen und nahegelegenen Radiosondenaufstiegen in der Modellatmosphäre führt zu einer weiteren signifikanten Verbesserung der abgeleiteten Temperaturprofile.

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3

Samtleben, Nadja, and Christoph Jacobi. "Long-period oscillations derived from mesosphere/lower thermosphere meteor radar temperature measurements." Universität Leipzig, 2015. https://ul.qucosa.de/id/qucosa%3A16649.

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Using measurements, derived from a meteor radar in Collm (51.3°N, 13°E), the mesopause region is analyzed with respect to the temperature distribution at an altitude of 90 km over a period of 10 years. The analyzed period lasts from 2005 till 2013. Based on these measurements, the typical temperature seasonal cycle of the mesopause region can be observed. The temperature reaches its minimum of about 130 K in summer and its maximum of about 220 K in winter. At this altitude, also strong day-today- fluctuations of up to 35 K exist, which are probably partly induced by planetary waves. Shorter-period oscillations with a period between 2 and 6 days have maximum amplitudes during summer, while longer-period oscillations with a period between 7 and 20 days maximize during winter. During the measurement period the amplitudes of oscillations with periods between 4 and 6 days, which may be attributed to the quasi-5-day-wave, increase with time.
Auf der Grundlage von Messungen eines Meteorradars in Collm (51.3°N, 13°E), die in einer Höhe von 90 km erfolgten, was in etwa der Mesopause entspricht, wird die Temperatur hinsichtlich ihres Jahresganges und insbesondere ihrer Variationen in einem Messzeitraum von 10 Jahren analysiert. Der analysierte Zeitraum erstreckt sich von 2005 bis 2013. Anhand der Daten kann man den typischen Jahresgang der Temperatur in der Mesopausenregion erkennen. Die Temperatur erreicht im Sommer das Minimum bei etwa 130 K und im Winter das Maximum bei etwa 220 K. Zudem treten starke Tag-zu-Tag-Fluktuationen auf, die im Maximum 35 K betragen. Diese werden vermutlich durch planetare Wellenaktivität der Atmosphäre hervorgerufen. Hierbei spielen im Sommer die kurzwelligen und im Winter die langwelligen Oszillationen, letztere mit Perioden größer 7 Tage, die wesentliche Rolle. Ferner sind innerhalb des Messzeitraums zunehmende Amplituden von Oszillationen mit Perioden zwischen 4 und 6 Tagen (quasi 5-Tage-Welle) zu erkennen.

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Jorge, Alfredo. "Medidas elétricas no policarbonato durolon e o metododa temperatura oscilante." Universidade de São Paulo, 1991. http://www.teses.usp.br/teses/disponiveis/54/54132/tde-21072009-174821/.

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Nesta tese procuramos caracterizar o Policarbonato Bisfenol-A, Durolon® sob o ponto de vista elétrico, separando a reação dipolar e os processos de condução. Apesar de preparadas de forma análoga, as amostras (≅ 30μm de espessura) mostraram comportamento pouco reprodutível, principalmente da componente condutiva. Várias anomalias foram detectadas embora não estudadas em detalhe pela pobre reprodutibilidade já mencionada. Além das técnicas usuais de polarização e despolarização isotérmicas, despolarização termoestimulada e de polarização termoestimulada, empregou-se pela primeira vez, em medidas desta natureza, a técnica de oscilação senoidal da temperatura, estando o campo elétrico aplicado. Media-se a corrente daí decorrente, procurando-se trabalhar sempre com uma mesma amostra. Na região de 50°C a 70°C, diferenças de fase superiores a 90° foram encontradas (o sinal de corrente atrasado em relação ao de temperatura). Uma análise simples destes resultados indica que, neste caso, tanto a condutividade como a suscetibilidade diminuem com o crescimento da temperatura (dX/dT≅ -1x10-3/°C). Medidas de polarização termoestimulada, também, mostram uma inversão da corrente em relação ao campo aplicado desde cerca da temperatura ambiente ate ≅ 90°C. Um estudo sistemático da condução a 120°C indica que portadores são emitidos do eletródio, e que o trânsito dos mesmos é rápido (menor do que o tempo em que a polarização se estabelece, ≅ 2 min). Tensões e correntes espontâneas foram detectadas mesmo em amostras providas de eletródios de mesmo metal (uma correlação com a ordem empregada na metalização foi suspeitada, seguindo observação anteriormente feita pelo Prof. B. Gross). Algumas medidas com eletródios Al-Al, Al-Au e Au-Au foram feitas. Finalmente, sugestões para trabalhos futuros são feitas.
In this work the electrical characterization of the Polycarbonate Bisphenol-A, Durolon ® was attempted, trying to separate the dipole and the conduction processes. However, poor reproducibility, mainly in the conductivity, was achieved even for samples (≅ 30μm thick usually) taken from the same batch. Anomalies were detected but not studied in detail owing the poor reproducibility referred above. Beside the usual techniques like the isothermal polarization and depolarization in short-circuit, thermally depolarization currents and thermally stimulated polarization, in a new one, employed by the first time for the study of transport and polarization, the temperature was oscillated and the ensuing current oscillation was monitored. Large phase shifts (the current lagging the temperature oscillation), even greater ≅ 90° were found in the range 50°C 70°C. A simple analysis indicates that in this case both the conductivity as well as the susceptibility are decreased for increasing temperature (dX/dT≅ -1x10-3/°C). Accordingly thermally stimulated polarization shows a current reversal with respect to the electric field from room temperature to ≅ 90°C. A systematic study of the conduction process at 120°C was carried out, the analysis of which indicates that carriers are emitted from the electrode, whose transit across the sample is shorter than the duration of the polarization current (≅ 2 min). Spontaneous tensions and currents were detected even for samples provisioned with similar electrodes (a correlation with the actual sequence of metallization, following a suggestion by Prof. B. Gross, was surmised). A few measurements with Al-Al, Al-Au and Au-Au electrodes were carried out. Finally suggestions for future work are given.

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Dugay, Murielle Boetcher Sandra Kathleen Sparr. "Errors in skin temperature measurements." [Denton, Tex.] : University of North Texas, 2008. http://digital.library.unt.edu/permalink/meta-dc-9786.

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Dugay, Murielle. "Errors in skin temperature measurements." Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc9786/.

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Numerical simulation is used to investigate the accuracy of a direct-contact device for measuring skin-surface temperature. A variation of thermal conductivity of the foam has greater effect on the error rather than a variation of the blood perfusion rate. For a thermal conductivity of zero, an error of 1.5 oC in temperature was identified. For foam pad conductivities of 0.03 and 0.06 W/m-oC, the errors are 0.5 and 0.15 oC. For the transient study, with k=0 W/m-oC, it takes 4,900 seconds for the temperature to reach steady state compared with k=0.03 W/m-oC and k=0.06 W/m-oC where it takes 3,000 seconds. The configuration without the foam and in presence of an air gap between the skin surface and the sensor gives the most uniform temperature profile.

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Stolle, Claudia, Martin Lange, and Christoph Jacobi. "Validation of atmospheric temperature profiles and electron densities derived from CHAMP radio occultation measurements during measurement campaigns at Andøya (69.28°N, 16.02°E)." Universitätsbibliothek Leipzig, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-217064.

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Several measurement campaigns took place at the ALOMAR observatory at Andøya, Northern Norway during July-November 2001 to validate ionospheric electron density and dry temperature profiles in the troposphere and lower stratosphere derived from radio occultation measurements of the low earth orbiter satellite CHAMP. For temperature sounding, three balloons are released around GPS satellite occultation events that occurred inbetween a distance of 200 km around Andøya. At altitudes of 7–20 km the CHAMP profile shows a positive mean deviation increasing with height by about 1.5-2 Kelvin/ 10 km overlayed with variations of ±1 K when compared to the radiosonde. Taking into account the previous and following radiosonde ascents the mean deviation seems to be of systematic nature due to the occultation principle or the retrieval algorithm and the variations are related to geographical variations of temperature and to the horizontal averaging by the radio occultation technique. During the period from mid July to mid August, four occultations for ionospheric soundings occurred. The values of the F2 layer calculated from the CHAMP derived electron density profiles are compared to the readings of the Alomar and Tromsø ionosondes for these times. Comparison shows that using the radio occultation technique electron densities of the maximum value layer are calculated inbetween the same order of magnitude as the ionosondes measurements, however, they overestimate it in the cases discussed here
Zur Validierung von Elekronendichte- und Temperaturprofilen, abgeleitet aus Radiookkultationsmessungen von CHAMP wurden im Juli-November 2001 mehrere Messkampagnen am ALOMAR Institut auf Andøya, Nordnorwegen durchgeführt. Zur Temperatursondierung wurden drei aufeinanderfolgende Radiosonden um den Zeitpunkt von Okkultationsereignissen im Umkreis von weniger als 200 km gestartet. Das hier diskutierte Temperaturprofil von CHAMP zeigt im Höhenbereich 7-20 km eine mit der Höhe zunehmende positive Abweichung von ca. 1,5-2 K/10 km mit Variationen um ±1 K verglichen mit dem Temperaturprofil der zum Okkultationszeitpunkt fliegenden Radiosonde. Der Vergleich mit den vorhergehenden und nachfolgenden Sondierungen lässt darauf schließen, dass die mittlere Abweichung durch systematische Fehler des Okkultationsverfahrens oder den Retrieval-Algorithmus bedingt sind, die Variationen jedoch durch die örtliche Abweichung und die horizontale Mittelung des Messverfahrens. Während des Zeitraumes von Mitte Juli bis Mitte August ereigneten sich vier Okkultationen zur Sondierung der Ionosphäre. Von den abgeleiteten Elektronendichteprofilen werden jeweils die Werte der F2-Schicht mit den zur gleichen Zeit gemessenen Elektronendichten der Ionosonden auf Andøya und bei Tromsø verglichen. Der Vergleich zeigt, dass mit Hilfe der Radiookkultaktionstechnik die Elektronendichtewerte der F2-Schicht in der gleichen Größenordnung berechnet, in diesen konkreten Fällen jedoch überschätzt werden

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8

Jacobi, Christoph, and Dierk Kürschner. "Mesopause region temperatures and plasma scale height estimations from VHF meteor radar and LF absolute reflection height measurements at Collm." Meteorologische Arbeiten aus Leipzig … und Jahresbericht … des Instituts für Meteorologie der Universität Leipzig ; 11 (2006), S. 1-10, 2006. https://ul.qucosa.de/id/qucosa%3A15363.

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The change of ionospheric absolute reflection heights h of low-frequency (LF) radio waves at oblique incidence in the course of the day is measured at Collm Observatory (51.3°N, 13.0°E) using 1.8 kHz sideband phase comparisons between the sky-wave and the ground wave of a commercial 177 kHz transmitter (Zehlendorf, reflection point 52.1°N, 13.2°E). Plasma scale height estimates H are calculated from the decrease/increase of h in the morning/evening. The day-to-day variations of H are compared with those of daily mean temperatures at 90 km, measured with a VHF meteor radar (36.2 MHz) at Collm utilising the amplitude decay of meteor reflections. A good qualitative correspondence is found between the two data sets. Since mesospheric long-period temperature variations are generally accepted to be the signature of atmospheric planetary waves, this shows that LF reflection height measurements can be used for monitoring the dynamics of the upper middle atmosphere.

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9

Blyth, William. "Temperature measurements of optically ionised plasmas." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386826.

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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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Kozlowski, Pawel. "Temperature and density measurements of plasmas." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:a436a632-d5aa-4e1a-8711-3814d059053c.

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Diagnosing the temperatures and densities of plasmas is critical to the understanding of a wide variety of phenomena. Everything from equations of state for warm dense matter (WDM) found in Jovian planets and inertial confinement fusion (ICF) to turbulent and dissipative processes in laser-produced plasmas, rely on accurate and precise measurements of temperature and density. This work presents improvements on two distinct techniques for measuring temperatures and densities in plasmas: x-ray Thomson scattering (XRTS), and Langmuir probes (LPs). At the OMEGA laser facility, experiments on warm dense matter were performed by firing lasers at an ablator foil and driving a planar shock into cryogenically cooled liquid deuterium. XRTS in the collective scattering regime was implemented to probe the matter, measuring densities of n_e ~ 4.3 x 10²³ cm^-3, temperatures of T_e ~ 12 eV and ionizations of Z ~ 1.0. Through an extension to XRTS theory for inhomogeneous systems, it was possible to extract an additional parameter, the length scale of the shock, whose value of ? ~ 1.33 nm was consistent with the predicted mean free path, and therefore the thickness of the shock. A unique triple Langmuir probe prototype was designed and tested at the Gregori group's lab at the University of Oxford. This probe was designed for a high temporal resolution of ~ 200 MHz for probing laser-produced shocks. The probes were used to measure the shock formed from ablating carbon rods in an argon gas fill. The probe yielded plasma parameters of n_e ~ 1.0 x 10¹⁷ cm^-3 , and T^e ~ 1.5 eV, consistent with measurements from interferometry and emission spectroscopy.

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Ragnarsson, David. "Sensor Integration for High Temperature Measurements." Thesis, Luleå tekniska universitet, EISLAB, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-64544.

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In today's mining industry, most of the sensor measurements in high temperature environments are expensive and the sensors are not well integrated with the materials treated in the hot temperatures. The conditions can vary much between the sensors location and where the materials are located. It is crucial to have high performance measurements to reach a more optimized control over the oven. A more optimized process gives a better combustion which decreases the fuel consumption and is more energy efficient. To increase the performance of these measurements, it is necessary to have wireless sensor systems, which can be well integrated with the materials and have a low cost. This so there is no need to use same system several times and it shouldn't matter if it gets destroyed in the oven. In this thesis, the focus lies on building the electronics and software for controlling a wide band oxygen sensor. The electronics are built by components with an upper temperature limit of 125 ◦C or above. The sensor itself is supposed to be heated up by an internal heating element. However, in these experiments, it is heated up by the surroundings in the oven. A major challenge in the work was the design of the control loop to keep the sensor in a correct and stable operating point. When initial oxygen measurements were compared with reference measurement done simultaneously in the oven, it didn't match well. These differences were shown to be caused by different locations of the sensor and the reference measurements. Further measurements in a live industrial setting confirmed the functionality of the system.

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Byström, Alexandra. "Compartment Fire Temperature Calculations and Measurements." Doctoral thesis, Luleå tekniska universitet, Byggkonstruktion och brand, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59927.

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This thesis is devoted to heat transfer and fire dynamics in enclosures. It consists of a main part which summarizes and discusses the theory of heat transfer, conservation of energy, fire dynamics and specific fire scenarios that have been studied. In the second part of this thesis, the reader will find an Appendix containing seven scientific publications in this field. In particular, one- and two-zone compartment fire models have been studied. A new way of calculating fire temperatures of pre- and post-flashover compartment fires is presented. Three levels of solution techniques are presented including closed form analytical expressions, spread-sheet calculations and solutions involving general finite element temperature calculations. Validations with experiments have shown good accuracy of the calculation models and that the thermal properties of the surrounding structures have a great impact on the fire temperature development. In addition, the importance of the choice of measurement techniques in fire engineering has been studied. Based on the conclusions from these studies, the best techniques have been used in further experimental studies of different fire scenarios.
Denna avhandling behandlar problem kopplade till värmeöverföring och branddynamik i slutna utrymmen med tonvikt på värmeöverföring mellan gaser och utsatta konstruktioner. Avhandlingen består av en huvuddel och ett appendix innehållande sju vetenskapliga artiklar. I huvuddelen sammanfattas och diskuteras grundläggande teorier och principer inom värmeöverföring och branddynamik samt studier av ett antal specialfall av brandscenarion som baseras på dessa teorier. I de avslutande bilagorna (Artiklar A1-A3 och Artiklar B1-B2) finns sju vetenskapliga artiklar som grundligare beskriver de ovan nämnda specialfallen. Huvudfokus i avhandlingen ligger på temperaturutveckling vid brand i slutna utrymmen. I avhandlingen studeras i synnerhet en- och två-zonsmodeller för brand i slutna utrymmen, och en ny metod för att beräkna brandgastemperaturer före och efter övertändning i rumsbränder är framtagen. Validering av dessa modeller med experiment visar att deras noggrannhet är bra. Modellerna visar också att de termiska egenskaperna hos de omgivande ytorna har stor inverkan på brandtemperatursutvecklingen. I tillägg studeras i denna avhandling betydelsen av val av mätmetoder i brandtekniska tillämpningar. På grundval av slutsatserna från dessa studier har de främsta mätteknikerna använts i ytterligare experimentella studier av olika brandscenarier.

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Jung, Fan. "Satellite measurements of surface temperatures." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308756.

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Southward, Emily S. "A comparison of auricular, rectal and pulmonary artery thermometry in dogs with anesthesia-induced hypothermia /." Free to MU Campus, others may purchase, 2005. http://wwwlib.umi.com/cr/mo/fullcit?p1429823.

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Björn, Linnéa, and Malin Forslin. "Continuous Measurements of the Pig-Iron Temperature." Thesis, KTH, Materialvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-101757.

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This report is about continuous temperature measurements of pig-iron at tapping from blast furnace 2 in Oxelösund, SSAB. Nowadays the temperature is only checked once at every tapping. The purpose of this project is to see if the process stability increases by continuously knowing the temperature and to compare the costs of this new technique with the technique used today. Possible savings due to less consumption of coke/coal if the silicon amount and the temperature are closer to their aim values will be regarded and if as little steam consumption as possible are used. The process stability can be divided into different sub goals. The ordinary measuring techniques were investigated as a part of the main goal; such as the ordinary measured temperature, the pig-iron and slag samples. The new continuous temperature measuring technique was compared with the ordinary temperature measurement and investigations of the life length were done. How representative the pig-iron and slag samples are, when taking them at the time they are today, are also looked into. The continuous measured temperature showed around 0,37 % higher temperature than the ordinary measured temperature. The pig-iron and slag samples should be taken as they are today, for mainly safety aspects. By using continuous temperature measurement, some of the sub goals can be achieved for a more stable process. The economy on the other hand has shown that large savings can be done by using this continuous temperature method due to a more stable process. This is mainly because of a decrease in steam usage in the experimental period. By regarding only the material of the methods the continuous temperature equipment is a bit more expensive, but the savings are much larger so the continuous temperature method is beneficial. With time this method could probably improve the process stability even more since the operators will deal with the information and the probe better.

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Thompson, C. E. "Thomson scattering measurements in low temperature plasmas." Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269139.

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Baker, Karen Irene. "Unsteady surface heat flux and temperature measurements." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-12042009-020124/.

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Cederlund, Jacob. "Radiated Susceptibility Measurements on Analogue Temperature Sensors." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279959.

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The need for electromagnetic compatibility is growing steadily as the usage of electronics in our daily lives is increasing more than ever. A common issue encountered in electromagnetic compatibility testing is analogue sensors that fail when exposed to electromagnetic fields. Testing how well electronics do when exposed to electromagnetic fields is called susceptibility testing, and standards for how to do these tests have been developed to ensure that the results of the tests can be reproduced. In this thesis work, analogue temperature sensors have been shielded using a few common techniques. The susceptibility of the sensors has been analysed by looking at their output voltage when the sensors were exposed to electro- magnetic fields of different field strengths. The output of the sensors was read by an Arduino that was shielded and tested to make sure it would not be affected by the electromagnetic fields used in the sensor tests. The result of the first set of sensor tests shows that shielding the cables running to the analogue temperature sensors and filtering away disturbances using ferrites gives a considerable decrease in susceptibility against electro- magnetic fields, while twisted cables and RC-filters did not. The results also showed that the introduction of a ground plane increased the susceptibility of the sensors, which most likely was due to it not providing the current with a path of less impedance and only served to increase the length of the unintentional antenna, which made it couple to the electromagnetic field more easily. However, during a second round of testing, the results of all the tests were hard to reproduce exactly, which calls into question how trustable the results of standardised susceptibility tests are. Therefore, when designing for the electromagnetic susceptibility of a product, a rather wide margin should be used in order to make sure that the product can reliably pass susceptibility tests.
Användningen av elektronik ökar i samhället och därför även nödvändigheten för testning av elektromagnetisk kompatibilitet. Ett vanligt problem inom elektromagnetisk kompatibilitet är att analoga sensorer lätt blir utstörda av elektromagnetiska fält. Hur man ska testa en elektronisk produkts känslighet mot elektromagnetiska fält styrs av standarder som ser till att resultaten av testerna går att återskapa. I detta examensarbete har analoga temperatursensorer skärmats med ett par vanliga metoder. Sensorernas känslighet har analyserats genom att undersöka hur deras utspänning påverkas när sensorn blir utsatt för elektromagnetiska fält med olika fältstyrkor. Sensorernas utspänning lästes av en Arduino som skärmades och testades för att se till all att den inte påverkades av de elektromagnetiska fälten som användes under testandet av sensorerna. Resultaten från de första sensortesterna visar att använda skärmade kablar till de analoga temeperatursensorerna och att filtrera bort störningar med ferriter sänkte sensorernas känslighet mot elektromagnetiska fält betydligt medan tvinnade kablar och RC filter inte gjorde det. Testerna visade också att jord- plan i detta fall ökade sensorernas känslighet då de inte erbjöd en bättre väg för strömmen att gå utan endast skapade en längre oavsiktlig antenn, vilket gjorde att den lättare kunde koppla till det elektromagnetiska fältet. Däremot visade det sig i en andra testomgång, att resultaten inte gick att återskapa ex- akt. Detta ifrågasätter hur tillförlitliga dessa standardiserade tester är och visar att man bör ha en ganska bred marginal när man designar för att minska en produkts känslighet mot elektromagnetiska fält, så att den på ett tillförlitligt sätt kommer kunna klara av känslighetstester.

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Wong, Yu Sang. "Temperature measurement of moving metal surfaces." access abstract and table of contents access full-text, 2006. http://libweb.cityu.edu.hk/cgi-bin/ezdb/dissert.pl?msc-ap-b21456288a.pdf.

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Thesis (M.Sc.)--City University of Hong Kong, 2006.
"Master of Science in Materials Engineering & Nanotechnology dissertation." Title from title screen (viewed on Nov. 21, 2006) Includes bibliographical references.

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Kulkarni, Rohan A. "The correlation length of temperature fluctuations measured in air using thermocouples." Diss., Online access via UMI:, 2005.

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Roth, Lyndsey B. "Modelling landcover-induced increases in daytime summer temperatures near Mount Adams, Washington." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 59 p, 2009. http://proquest.umi.com/pqdweb?did=1885544291&sid=4&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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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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Magalhães, Ana. "Thermo-electric temperature measurements in friction stir welding : Towards feedback control of temperature." Licentiate thesis, Högskolan Väst, Avdelningen för produktionssystem (PS), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-9982.

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Friction Stir Welding has seen a fast uptake in many industry segments. Mechanical properties superior to fusion welding, the ability to weld "unweldable" aluminium alloys and low distortion are often described as the main reasons for the fast industrial implementation of FSW. Most existing applications consist of long straight welding joints. Applications with complex weld geometries, however, are rarely produced by FSW. These geometries can induce thermal variations during the welding process, thus making it challenging to maintain a consistent weld quality. In-process adaptation of weld parameters to respond to geometrical variations and other environmental variants allow new design opportunities for FSW. Weld quality has been shown to be reliant on the welding temperature. However, the optimal methodology to control the temperature is still under development.The research work presented in this thesis focuses on some steps to take in order to reach the improvement of the FSW temperature controller, thus reach a better and consistent weld quality. In the present work different temperature methods were evaluated. Temperature measurements acquired by the tool-workpiece thermocouple (TWT) method were accurate and fast, and thereby enhanced suitable for the controller. Different environmental conditions influencing the material heat dissipation were imposed in order to verify the controller effect on the joint quality. In comparison with no controlled weld, the use of the controller enabled a fast optimization of welding parameters for the different conditions, leading to an improvement of the mechanical properties of the joint.For short weld lengths, such as stitch welds, the initial plunge and dwell stages occupy a large part of the total process time. In this work temperature control was applied during these stages. This approach makes the plunge and dwell stages more robust by preventing local material overheating, which could lead to a tool meltdown. The TWT method was demonstrated to allow a good process control during plunging and continuous welding. The approach proposed for control offers weld quality consistency and improvement. Also, it allows a reduction of the time required for the development of optimal parameters, providing a fast adaptation to disturbances during welding and, by decreasing the plunge time, provides a significant decrease on the process time for short welds.

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Jarboe, Jason Neal. "A method for infrared temperature measurements of thin film materials with a low, unknown, and/or variable emissivity at low temperatures." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/84401.

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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.
Cataloged from PDF version of thesis.
Includes bibliographical references.
Accurate non-contact temperature measurements of objects using thermal radiation is often limited by low emission of IR radiation because of low temperatures and/or emissivities, or by the unknown or changing emissivity of the material being measured. This thesis covers an effort to build a practical, inexpensive, and widely applicable non-contact system for accurately measuring the temperatures of materials of low, unknown, and/or variable emissivity. The method to be used is intended specifically for those objects at low temperatures (below 100 degrees Celsius), which are conventionally the most difficult to accurately measure.
by Jason Neal Jarboe.
S.B.

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26

Lee, Robert Benjamin III. "Tropospheric temperature measurements using a rotational raman lidar." Thesis, Hampton University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3592881.

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Using the Hampton University (HU) Mie and Raman lidar, tropospheric temperature profiles were inferred from lidar measurements of anti-Stokes rotational Raman (RR) backscattered laser light from atmospheric nitrogen and oxygen molecules. The molecules were excited by 354.7 nanometer (nm) laser light emitted by the HU lidar. Averaged over 60-minute intervals, RR backscattered signals were detected in narrow 353.35 nm and 354.20 nm spectral bands with full-widths-at-half-maxima (FWHM) of 0.3 nm. During the special April 19-30, 2012, Ground-Based Remote Atmospheric Sounding Program (GRASP) campaign, the lidar temperature calibration coefficients were empirically derived using linear least squares and second order polynomial analyses of the lidar backscattered RR signals and of reference temperature profiles, obtained from radiosondes. The GRASP radiosondes were launched within 400 meters of the HU lidar site. Lidar derived temperature profiles were obtained at altitudes from the surface to over 18 kilometers (km) at night, and up to 5 km during the day. Using coefficients generated from least squares analyses, nighttime profiles were found to agree with profiles from reference radiosonde measurements within 3 K, at altitudes between 4 km and 9 km. Coefficients generated from the second order analyses yielded profiles which agreed with the reference profiles within 1 K uncertainty level in the 4 km to 10 km altitude region. Using profiles from GRASP radiosondes, the spatial and temporal homogeneities of the atmosphere, over HU, were estimated at the 1.5 K level within a 10 km radius of HU, and for observational periods approaching 3 hours. Theoretical calibration coefficients were derived from the optical and physical properties of the HU RR lidar and from the spectroscopic properties of atmospheric molecular nitrogen and oxygen. The theoretical coefficients along with lidar measurements of sky background radiances were used to evaluate the temporal stability of the empirically derived temperature profiles from the RR lidar measurements. The evaluations revealed systematic drifts in the coefficients. Frequent reference radiosonde temperature profiles should be used to correct for the drifts in the coefficients.

For the first time, the cause of the coefficient drifts has been identified as the differences in the aging of the spectral responses of the HU lidar detector pairs. For the first time, the use of lidar sky background measurements was demonstrated as a useful technique to correct for the coefficient drift. This research should advance the derivations of lidar temperature calibration coefficients which can be used for long observational periods of temperature fields without the need for frequent lidar calibrations using radiosondes.

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Beaucage, Timothy Ray. "High Temperature LGT Expansion Measurements through Multiple Techniques." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/BeaucageTR2007.pdf.

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Ugarte, Alejandro R. "Modeling for improved minimum resolvable temperature difference measurements." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/28367.

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Approved for public release; distribution is unlimited
The minimum resolvable temperature difference (MRTD) is widely accepted as the parameter that best describes the field performance of a thermal imaging system (TIS). Mathematical modeling that accurately predicts the MRTD has been of major interest to the infrared community over the last 10 years. This work reviews the currently accepted models for predicting the MRTD. Simplifying assumptions used by these models which deal with target spectrum are discussed and tested using specifications taken from a standard forward looking infrared (FLIR) system. In addition new models are proposed and tested. Two of these models are a direct extension of the recently proposed Vortman-Bar-Lev adaptive matched filter. A third model is based on the novel concept that the MRTF curve is predictable from a threshold condition on the visibility, rather than the signal-to-noise ratio, of the system-degraded bar pattern.

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Tsembelis, Kostantinos. "Elevated temperature measurements during a hypervelocity impact process." Thesis, University of Kent, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285978.

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Cheim, Luiz A. V. "Arc temperature measurements in high breaking capacity fuses." Thesis, University of Nottingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335758.

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Hanna, Ghassan Faraj 1957. "DESIGN AND DEVELOPMENT OF HIGHLY ACCURATE TEMPERATURE MEASUREMENT INSTRUMENTATION FOR USE IN HOSTILE ENVIRONMENT." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/276351.

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石燦鴻 and Chan-hung Shek. "Ferrite decomposition in duplex stainless steel and its application intemperature measurement." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1994. http://hub.hku.hk/bib/B31233880.

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Shek, Chan-hung. "Ferrite decomposition in duplex stainless steel and its application in temperature measurement /." [Hong Kong : University of Hong Kong], 1994. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13867660.

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34

Ort, Coenraad M. "Spatial and temporal variability of Cross-Basin acoustic ray paths." Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA241544.

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Thesis (M.S. in Oceanography)--Naval Postgraduate School, December 1990.
Thesis Advisor(s): Chiu, Ching-Sang ; Sentner, Albert J. "December 1990." Description based on title screen as viewed on March 30, 2010. DTIC Identifier(s): Hamiltonian raytracing, greenhouse warning, Cross-Basin acoustic raytracing. Author(s) subject terms: Hamiltonian raytracing, greenhouse warning, Cross-Basin acoustic raytracing. Includes bibliographical references (p. 78-80). Also available in print.

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Huebschman, Michael Lee. "Spectroscopic measurements in low temperature in low temperature inductively coupled RF discharges in hydrogen /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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36

Wilson, Simon J. "Thermal profiles in oxygen vacuum swing adsorption (VSA) : modelling, observations and optimisation." Monash University, Dept. of Chemical Engineering, 2001. http://arrow.monash.edu.au/hdl/1959.1/7766.

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37

Stolle, Claudia, Martin Lange, and Christoph Jacobi. "Validation of atmospheric temperature profiles and electron densities derived from CHAMP radio occultation measurements during measurement campaigns at Andøya (69.28°N, 16.02°E)." Universität Leipzig, 2002. https://ul.qucosa.de/id/qucosa%3A15224.

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Several measurement campaigns took place at the ALOMAR observatory at Andøya, Northern Norway during July-November 2001 to validate ionospheric electron density and dry temperature profiles in the troposphere and lower stratosphere derived from radio occultation measurements of the low earth orbiter satellite CHAMP. For temperature sounding, three balloons are released around GPS satellite occultation events that occurred inbetween a distance of 200 km around Andøya. At altitudes of 7–20 km the CHAMP profile shows a positive mean deviation increasing with height by about 1.5-2 Kelvin/ 10 km overlayed with variations of ±1 K when compared to the radiosonde. Taking into account the previous and following radiosonde ascents the mean deviation seems to be of systematic nature due to the occultation principle or the retrieval algorithm and the variations are related to geographical variations of temperature and to the horizontal averaging by the radio occultation technique. During the period from mid July to mid August, four occultations for ionospheric soundings occurred. The values of the F2 layer calculated from the CHAMP derived electron density profiles are compared to the readings of the Alomar and Tromsø ionosondes for these times. Comparison shows that using the radio occultation technique electron densities of the maximum value layer are calculated inbetween the same order of magnitude as the ionosondes measurements, however, they overestimate it in the cases discussed here.
Zur Validierung von Elekronendichte- und Temperaturprofilen, abgeleitet aus Radiookkultationsmessungen von CHAMP wurden im Juli-November 2001 mehrere Messkampagnen am ALOMAR Institut auf Andøya, Nordnorwegen durchgeführt. Zur Temperatursondierung wurden drei aufeinanderfolgende Radiosonden um den Zeitpunkt von Okkultationsereignissen im Umkreis von weniger als 200 km gestartet. Das hier diskutierte Temperaturprofil von CHAMP zeigt im Höhenbereich 7-20 km eine mit der Höhe zunehmende positive Abweichung von ca. 1,5-2 K/10 km mit Variationen um ±1 K verglichen mit dem Temperaturprofil der zum Okkultationszeitpunkt fliegenden Radiosonde. Der Vergleich mit den vorhergehenden und nachfolgenden Sondierungen lässt darauf schließen, dass die mittlere Abweichung durch systematische Fehler des Okkultationsverfahrens oder den Retrieval-Algorithmus bedingt sind, die Variationen jedoch durch die örtliche Abweichung und die horizontale Mittelung des Messverfahrens. Während des Zeitraumes von Mitte Juli bis Mitte August ereigneten sich vier Okkultationen zur Sondierung der Ionosphäre. Von den abgeleiteten Elektronendichteprofilen werden jeweils die Werte der F2-Schicht mit den zur gleichen Zeit gemessenen Elektronendichten der Ionosonden auf Andøya und bei Tromsø verglichen. Der Vergleich zeigt, dass mit Hilfe der Radiookkultaktionstechnik die Elektronendichtewerte der F2-Schicht in der gleichen Größenordnung berechnet, in diesen konkreten Fällen jedoch überschätzt werden.

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38

Griffioen, Jan Arie. "Temperature measurements in tribocontacts by means of infrared radiometry." Diss., Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/16810.

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39

Cheung, Terence Chi-Hin 1980. "Room temperature transport measurements on Bridgman-grown Culn₁-xGaxSe₂." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97879.

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Filamentary samples were cut from ingots of the chalcopynte semiconductor CuIn1-x,GaxSe2, grown by a vertical Bridgman method for compositions x = 0, 0.2, and 0.3. On these, room-temperature measurements were made of thermoelectric power (alpha), Hall coefficient (RH), and electrical conductivity (sigma). Analysis of the measured results was made on a two-carrier basis, taking the minority electrons into account. Assuming dominant acoustic lattice scattering and an effective hole mass ratio, m p/m0 = 0.7, the only common acceptable value for the electron-to-hole mobility ratio, b, was found to be b = 5, for all filamentary samples. Using this value, hole concentrations were found to be lower than those derived from a one-carrier model, and hole mobilities were correspondingly higher. The mobilities in quaternary samples were lower than those in the ternaries. Furthermore, the hole concentrations were much higher in the quaternary filaments cut from the end of the grown ingots than from the middle.

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Mizera, Michel Adam. "Ignition temperature measurements of metallic sulfides in SHS processes." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28007.

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The quasi-steady-state ignition temperature was measured for the following metal-sulfur compounds: Cr-S, Mo-S, Mg-S, Mn-S, Si-S, Ti-S and Zn-S. The ignition temperatures for these mixtures ranged from 350$ sp circ$C to 600$ sp circ$C. For a same element (Mn) an increase in particle size of the metal reactant caused an increase in the ignition temperature of the mixture. For the Mn + S system, preliminary estimates using classical thermal explosion theory indicate that an apparently low activation energy reaction is present. Estimates of the activation energy derived from the results of transient ignition experiments involving Mn-S and Cr-S mixtures with large metal particle reactants yield similar low values. It is suggested that the classical method of solution using a high-activation energy assumption to solve the heat conduction equation modeling the reaction may be inappropriate. Modifications to the zeroth-order reaction term in the model which incorporate reactant consumption, diffusion kinetics or two-step reactions could improve modeling results.

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Dash, Prasanjit. "Land surface temperature and emissivity retrieval from satellite measurements." Karlsruhe : Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft, 2005. http://bibliothek.fzk.de/zb/berichte/FZKA7095.pdf.

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42

Mizera, Michel-Adam. "Ignition temperature measurements of metallic sulfides in SHS processes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ37274.pdf.

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43

Sphicas, Panagiotis. "High pressure and high temperature measurements on diesel sprays." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/18063.

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Environmental, financial and legal reasons demand the development of cleaner diesel engines. Atomization, evaporation and mixing phenomena observed during injection of Diesel fuel affect the produced emissions. To study these phenomena, under engine-like conditions (50bar, 1000K), a chemically preheated constant volume chamber was built. A system of sensors, driven in real-time by a FPGA (Field Programmable Gate Array) and controlled by a Real Time Controller, was built to monitor and control the operations. A modern common rail fuel injection system (Bosch CP3) was driven by a purpose-modified Hartridge 1100 test stand and controlled by the FPGA (Field Programmable Gate Array). Chemical heating is a technique used widely to simulate the ambient conditions of an industrial combustor in a constant volume vessel. A flammable mixture is ignited in an optically accessible vessel, attempting to produce a post-combustion high pressure and high temperature environment. The flammable mixture usually consists of Hydrogen and a Hydrocarbon. Hydrogen is added, to assist with the ignitability of the pre-ignition mixture and to simulate the water present in industrial combustors as a result of exhaust gas recirculation. To this direction, the mole ratio of Hydrogen to Hydrocarbon and the mixture molecular weight were introduced as independent variables for the first time in the literature of constant volume combustion. An initial computer model, assuming perfect combustion, was used for calculation of adiabatic temperature and pressure. A second computer model investigated the effect of chemical dissociation by solving for the minimization of Gibbs energy and was compared to the former one. To verify the calculations, a dual pressure transducer technique and a High-Speed Schlieren technique were used to validate the combustion conditions inside the vessel To further understand the atomization, evaporation and mixing phenomena in sprays, a Diesel spray was visualized using back-illumination and Schlieren High-Speed cinematography at high pressure and room temperature. To understand the evaporation behaviour of a spray and map the vapour fuel distribution, a tracer Laser Induced Fluorescence was applied on a Dodecane/Methyl-naphthalene spray under evaporating and non-evaporating conditions. To compare the experimental findings to the theoretical models in literature, the evaporation of a single droplet in post-combustion vessel gases was simulated using a purpose-programmed FORTRAN code. A supercritical phase change was suggested to explain the sudden phase change and large differences between the theoretical model and the experimental results.

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Jacobson, Carl P. "Temperature corrected strain measurements using optical time domain reflectometry." Thesis, Virginia Tech, 1990. http://hdl.handle.net/10919/41906.

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A method of using optical fiber to measure strain and correct for the effects of temperature is proposed. A means of measuring apparent strain is given, pure temperature is measured using Fresnel-backscatter based Optical Time Domain Reflectametry, and a method for combining the two measurements to obtain a measurement of mechanically-induced strain alone is developed. The background, theory and experimental results that demonstrate the feasibility of such a system are presented and the results are compared with the performance of existing fiber-based means of measuring temperature. Experiments on several OTDR-addressed, intensity-based optical temperature sensors are performed and a method for manufacturing small air gap splices for use in measuring strain at several places along an optical fiber are presented.
Master of Science

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45

McDannold, Nathan J. "MRI monitoring of high temperature ultrasound therapy /." Thesis, Connect to Dissertations & Theses @ Tufts University, 2002.

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Thesis (Ph.D.)--Tufts University, 2002.
Adviser: David Weaver. Submitted to the Dept. of Physics. Includes bibliographical references (leaves 218-243). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

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46

Reyes, de Corcuera José Ignacio. "Increased sensitivity of enzyme-based amperometric glucose biosensors and their application as time-temperature integrators." Online access for everyone, 2004. http://www.dissertations.wsu.edu/Dissertations/Spring2004/J%5FDe-Corcuera%5F050404.pdf.

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47

Clegg, Scott Tom. "Estimation of three-dimensional temperature fields from a limited number of transient temperature measurements during hyperthermia." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184424.

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In this dissertation, a new reconstruction algorithm to estimate the complete temperature field during hyperthermia is developed which relies upon a limited amount of transient measured temperature data. The predictive capabilities of this new algorithm are then systematically studied; first using one-dimensional simulated treatments, then using three-dimensional simulated treatments, and finally applying it to hyperthermia treatments of normal canine thighs. It was found that this new algorithm predicts the complete temperature fields more accurately and robustly than the steady-state approach. In particular, it can better predict the complete temperature fields in situations where the number of unknown blood perfusion parameters are greater than the number of available temperature sensors. It was also found that the steady-state temperature field could be estimated to within 1°C if there was no measurement noise, no model mismatch, and as few as three measurement locations for seven perfusion zones. The addition of measurement noise degraded the performance of this estimation algorithm especially when the number of measurement locations was small. It was found that use of Tikhonov regularization of order zero significantly improved the performance of the algorithm and that there was an optimal choice for the regularization parameter. For the animal experiments, normal canine thighs were instrumented with one-hundred twelve thermocouples and heated to steady-state using a 6 cm planar ultrasound transducer operating at 0.5 MHz: then the power was turned off and the transient cool down temperature data was stored for later use by the reconstruction algorithm. Only a subset of the one-hundred twelve measurements was used as input to the reconstruction algorithm. The remaining measurements were used to compare the results of the reconstruction algorithm with the true temperatures. The results showed that in general the predicted perfusion and reconstructed temperature field did not change significantly as sensors were removed. However, the error was quite large for some of the situations studied particularly when only twenty-seven piecewise constant regions of perfusion were used. Increasing the number of perfusion regions reduced this error suggesting that model mismatch had contributed significantly to the error.

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Lee, Sheng-Chiang. "Measurements of doping dependent microwave nonlinearities in high-temperature superconductors." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1372.

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Thesis (Ph. D.) -- University of Maryland, College Park, 2004.
Thesis research directed by: Physics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

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Palmer, Paul Ian. "Analysis of atmospheric temperature and humidity from radio occultation measurements." Thesis, University of Oxford, 1998. http://ora.ox.ac.uk/objects/uuid:9d6f02de-527a-46b4-acda-2e8723f27f50.

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Radio occultation measurements from global navigation satellite systems, such as the Global Positioning System (GPS), represent a new source of numerical weather prediction information. Conventionally, radio occultation measurements are inverted using an Abel integral transform to obtain a profile of refractivity, and subsequently pressure, on geometric height levels via the hydrostatic relation. Although accurate temperature/water vapour retrievals are possible with a background estimate of water vapour/temperature, it is not possible to retrieve these quantities simultaneously using this method. Also, using this method, refractivity retrieval errors are introduced by assuming no horizontal structure local to ray periapsis (the spherical symmetry assumption), and the method is subject to 'first-guess' errors when the hydrostatic relation is initialised. Results from an investigation into how departures from spherical symmetry affect the performance of the Abelian inverse method are presented. It is shown that realistic horizontal humidity inhomogeneities can compensate for or reinforce horizontal temperature inhomogeneities, and therefore are important to consider in both the forward and inverse modelling. Using the results from this experiment, regression coefficients are fitted in an effort to predict temperature and refractivity retrieval errors from the horizontal temperature and humidity structure local to the measurement. The largest contribution to the predicted errors is shown to be from the local parabolic component of the horizontal structure, but is found to predict only a small fraction of the total error. A non-linear optimal estimation inverse method is presented with which it is possible to retrieve simultaneously profiles of temperature, humidity and surface pressure. Using this method, the measurements are assimilated with a priori information utilising error estimates of the a priori information and the measurements. The method implemented is validated using an ensemble of numerical simulations. Real observations from the GPS/MET pilot experiment are used to retrieve profiles of temperature, humidity and surface pressure which are validated using collocated ECMWF and NMC model analyses, radiosondes, and the Abelian inversion results. Temperature and refractivity comparisons between the optimal estimate and results from the Abelian inverse method show good agreement at high latitudes for all altitudes, resolving small-scale structure not shown by the model analyses. At low latitudes there is good agreement above the tropopause, below which a temperature bias ensues between the Abelian inversion and all other correlative data. Retrieved values for water vapour and surface pressure compare well with model analyses and collocated radiosondes. Biases between the UKMO and the ECMWF model analyses are consistent with known differences between the two models at the time of the dataset.

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Baeraky, Thoria A. "High temperature measurements of the microwave dielectric properties of ceramics." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323185.

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Dissertations / Theses on the topic 'Temperature measurents'

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