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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Measurements of thermal properties and blood perfusion using the heat flux microsensor /

Michener, Michael Douglas, January 1991 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University,1991. / Vita. Abstract. Includes bibliographical references (leaves 113-115). Also available via the Internet.
2

Measurements of thermal properties and blood perfusion using the heat flux microsensor

Michener, Michael Douglas 17 March 2010 (has links)
A thin-film heat flux sensor was used in two transient conduction applications. First it was used in a device for simultaneously determining the thermal conductivity, κ, and the thermal diffusivity, α, of solid materials. The device was heated and then touched to metal samples at room temperature. The thermal properties were characterized based on the heat flux response of the gage, and the change in temperature of the metal surface at a specified distance away from the gage. A finite difference program was developed and used to model the system response. The effect of α was most evident by the time delay in the temperature response on the metal surface. The effect of κ was most evident in the heat flux response after the first few seconds of contact. In the second application, the gage was used in a probe that was cooled and then touched to biological materials. A numerical model was used to demonstrate the effect of tissue blood perfusion on the surface heat flux. Experimental tests were performed on live dogs. Both the numerical model and the experiments showed that increases in blood perfusion could be detected from the transient heat flux measurements. In both applications, this research forms the basis for instrumentation which will be able to measure κ, α, and blood perfusion. / Master of Science
3

A Translating Fluxmeter for Solenoid Measurements

Mattsson Kjellqvist, Ville January 2024 (has links)
At the European Institute for Nuclear Research, CERN, a new electron cooler is being commissioned for the Antiproton Decelerator experiment. In this experiment protons are shot into a block of metal, which creates anti protons. These anti protons will thereafter be focused into a particle beam, a process done in several steps. One of these steps is with an electron cooler. This cooler shoots electrons into the ion-beam path. These electrons then collide with the beam particles, and momentum is transferred from the beam particles to the electrons. The electrons are then steered away from the beam path, into an electron collector. In the beam path drift of the cooler, where the anti protons and electrons meet, a normal conducting solenoid magnet is used to orient the electron path. This magnet comes with strict requirements on field quality, such that the transversal magnetic field must be less than 10 ppm of the lateral field. In this thesis a metrological characterization of a prototype measurement system for solenoidal magnets is presented. Instead of winding measurement coils with wire, they are instead printed on a circuit board over ten layers. Of particular interest was the magnet alignment with respect to the beam aperture, so that the magnetic solenoid axis is in line with the aperture central axis. For this purpose, a mathematical model for solenoidal magnetic fields has been constructed. This model can be used to quantify the sensitivity of the measurement system for an unaligned magnet. Furthermore, some test measurements are presented, along with some simulation campaigns to further characterize the problem. A specific method where the magnetic field peaks are used to measure the alignment is evaluated. / På den Europeiska organisationen för Kärnforskning pågår just nu ett uppgraderingsarbete för AD-experimentet, (fullständigt namn på engelska: Antiproton Decelerator). I detta experiment skjuts protoner in i ett block med metall, vilket skapar antiprotoner. Dessa antiprotoner ska sedan fokuseras till en partikelstråle, vilket görs i en rad olika steg, däribland med vad som kallas för en elektronkylare. Elektronkylaren skjuter in elektroner i partikelstrålens väg, vilka kolliderar med antiprotonerna och på detta sätt reducerar temperaturen i partikelstrålen genom att överföra momentum till elektronerna. Elektronerna leds sedan bort ur strålens väg, in i en elektronsamlare.I strålaperturen, där elektronerna och antiprotonerna möts, används en normalledande solenoidmagnet för att styra elektronerna. Dennasolenoidmagnet kommer med strikta krav på den magnetiska fältprofilen,varför känslig mätutrustning krävs. Det magnetiska fältet måste vara av solenoid karaktär, så att det transversella fältet är mindre än 10 ppm av det longitudinella. I denna rapport presenteras en metrologisk karaktärisering av en ny prototyp på mätsystem för solenoidmagneter. Istället för att linda spolar som en mäter fältkvalitén med, så har dessa istället tryckts på ett kretskort över tio lager. Av speciellt intresse var att mäta magnetens justering, så att solenoidaxeln ligger i linje med strålaperturen. För detta ändamål så har en matematisk modell för solenoida magnetfält konstruerats. Denna modell kan användas för att kvantifiera känsligheten hos mätsystemet för en ojusterad solenoidmagnet. Vidare så presenteras testmätningar med systemet, samt en rad simulationer för att vidare karaktärisera problemet. En specifik mätmetodik där magnetfältstopparna används för att undersöka magnetens justering utvärderas.

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