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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.
71

Recovery and recrystallization in FCC metals after high temperature deformation

Petković-Luton, Ružica Aleksandra. January 1975 (has links)
No description available.
72

The decomposition of molybdenum disulphide in an induction plasma tailflame/

Munz, Richard J. (Richard Jürg) January 1974 (has links)
No description available.
73

Indentation creep and anisotropy in magnesium oxide and germanium

Everitt, Nicola Mary January 1990 (has links)
Hardness tests have the potential to provide a simple means of investigating the mechanical properties of materials, both at room temperature, and at higher temperatures. However, the information gained can not be fully utilized unless the deformation processes and variables are properly understood. Careful consideration of such deformation on single crystals can help to clarify the situation and lead to better understanding. This thesis describes indentation experiments on (001) MgO and Ge at temperatures up to 1175°C and 700°C respectively. Since anisotropy was one of the questions being addressed, the majority of the testing used Knoop indenters, although a few experiments used Vickers indenters. The work was carried out on a specially commissioned high temperature hardness tester (based on an original design by Wilberforce Scientific Developments). A main conclusion of the discussion on the design of high temperature hardness testers is the importance of independent heating of the indenter for accurate hardness results. The indentation behaviour of MgO was shown to include creep, even at room temperature for the Knoop <110> orientation. However a region of no indentation creep was exhibited between 750°C and 1050°C for both Vickers and Knoop indentations. This has not been reported in previous studies. The anisotropy displayed at room temperature between <110> and <100> Knoop decreased with increasing temperature, due to the faster creep rate of the < 110> orientation, and finally reversed. Knoop indentations in the <110> and <100> orientations on Ge also showed hardness anisotropy which changed with temperature. In this case there was no anisotropy at room temperature, but anisotropy developed as the temperature increased due to the faster creep rate of the <110> orientation. The indentation hardness response of both MgO and Ge is explained in terms of the interaction of dislocation arrays which are formed in the first few moments of the indentation. Measurement of the two diagonals of the Knoop indentations showed that the ratio of the diagonal lengths, and also the morphology of the surrounding material, can be used to examine the extent and direction of material displacement. Surface etching, and etching of sections, were used to analyse the disposition of slip around the indentations.
74

Development of a binary mixture gas composition instrument for use in a confined high temperature environment

Cadell, Seth R. 28 November 2012 (has links)
With recent advancements in material science, industrial operations are being conducted at higher and higher temperatures. This is apparent in the nuclear industry where a division of the field is working to develop the High Temperature Gas Reactor and the Very High Temperature Gas Reactor concurrently. Both of these facilities will have outlet gas temperatures that are at significantly higher temperatures than the typical water cooled reactor. These increased temperatures provide improved efficiency for the production of hydrogen, provide direct heating for oil refineries, or more efficient electricity generation. As high temperature operations are being developed, instruments capable of measuring the operating parameters must be developed concurrently. Within the gas reactor community there is a need to measure the impurities within the primary coolant. Current devices will not survive the temperature and radiation environments of a nuclear reactor. An instrument is needed to measure the impurities within the coolant while living inside the reactor, where this instrument would measure the amount of the impurity within the coolant. There are many industrial applications that need to measure the ratio of two components, whether it be the amount of particulate in air that is typical to pneumatic pumping, or the liquid to gas ratio in natural gas as it flows through a pipeline. All of the measurements in these applications can be met using a capacitance sensor. Current capacitance sensors are built to operate at ambient temperatures with only one company producing a product that will handle a temperature of up to 400 °C. This maximum operating temperature is much too low to measure the gas characteristics in the High Temperature Gas Reactor. If this measurement technique were to be improved to operate at the expected temperatures, the coolant within the primary loop could be monitored for water leaks in the steam generator, carbon dust buildup entrained in the flow, or used to measure the purity of the coolant itself. This work details the efforts conducted to develop such an instrument. While the concept of designing a capacitance sensor to measure a gas mixture is not unique, the application of using a capacitance sensor within a nuclear reactor is a new application. This application requires the development of an instrument that will survive a high temperature nuclear reactor environment and operate at a sensitivity not found in current applications. To prove this technique, instrument prototypes were built and tested in confined environments and at high temperatures. This work discusses the proof of concept testing and outlines an application in the High Temperature Test Facility to increase the operational understanding of the instrument. This work is the first step toward the ultimate outcome of this work, which is to provide a new tool to the gas reactor community allowing real-time measurements of coolant properties within the core. / Graduation date: 2013
75

Effect of gas density on corrosion in horizontal multiphase slug flow at high temperatures and pressures

Krishnamoorthy, Vijay. January 1997 (has links)
Thesis (M.S.)--Ohio University, November, 1997. / Title from PDF t.p.
76

Oxygen isotope salt effect at high pressure and high temperature /

Hu, Guixing. January 2000 (has links)
Thesis (Ph. D.)--University of Chicago, Dept. of Geophysical Sciences, December 2000. / Includes bibliographical references. Also available on the Internet.
77

Developing the capability to examine environmental effects on small fatigue crack growth

Gockel, Brian Timothy, January 2010 (has links)
Thesis (M.S. in Mechanical Engineering) -- University of Dayton. / Title from PDF t.p. (viewed 06/22/10). Advisor: Robert Brockman. Includes bibliographical references (p. 42-44). Available online via the OhioLINK ETD Center.
78

Studies at high temperatures I. Sublimation pressures of alkaline earth fluorides by mass spectrometric techniques. II. Statistical mechanical calculations of thermodynamic functions of the elemental +1 +2 +3 and +4 ions. III. Corrected optical pyrometer readings. IV. Vacuum ultraviolet absorption spectrum of chlorine /

Green, John William, Poland, D. E. Margrave, John L. January 1963 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Includes: Thermodynamic properties of ions at high temperatures / John W. Green, Duncan E. Poland, John L. Margrave. (Wright-Patterson Air Force Base, Ohio : Aeronautical Research Laboratory, Office of Aerospace Research, United States Air Force, 1961) -- Ideal gas thermodynamic functions of some selected elements / D.E. Poland, J.W. Green and J.L. Margrave. Reprinted from Journal of chemical & engineering data, v. 7, no. 3 (July 1962), p. 389-390 -- Corrected optical pyrometer readings / D.E. Poland, J.W. Green and J.L. Margrave. National Bureau of Standards monograph ; 30 (Washington, 1961), 74 p. -- Absorption spectrum of chlorine in the vacuum ultraviolet / Raymond P. Iczkowski, Raymond P., John L. Margrave and John W. Green. Reprinted from Journal of chemical physics, v. 33, no. 4 (Oct. 1960), p. 1261-1262. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
79

Creep lifing methods for components under high temperature creep

Abdallah, Zakaria January 2010 (has links)
No description available.
80

Sapphire fiber based high temperature extensometer

Fang, Xiaojun 26 January 2010 (has links)
<p>New sapphire fiber based sensor structures for high temperature strain measurement are proposed and studied in this report. The self-mixing interferometry has been studied and tested. The advantage of this technique is the source coherence insensitivity and direction distinguishment capability. Fringes of the self-mixing interferometer built with standard multimode fiber and sapphire fiber were observed. The application of this technique to static strain rneasurement seems difficult to stabilize, whereas its implementation to acoustic sensing with single-mode fiber coil as the sensing component will be very interesting. The approach by Moire interferometry and equal-path coherence matching interferometer are two promising methods for high temperature displacement measurement. The advantages of the Moire interferometer are source coherence independence and large measurement range. The advantage of coherence matching absolute interferometer is its simplicity in sensor structure. The structures of coherence matching methods and multiplexing techniques are generalized. From this research, we can conclude that the sapphire fiber based high temperature extensometer may be realized by different methods.</p> / Master of Science

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