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Defects in Aluminum, Stainless steel and galvanized steel sheets are studied in reflection mode infrared thermography. The effect of material properties, surface finish, heating intensity, heater emission spectra, pixel size and defect size are studied. Contrast is governed by heat quality, emissivity and defect geometry—which follows a logarithmic trend. The diameter detected via infrared thermography is found to be at least 30% larger than the measured diameter and sub-pixel defects can be detected. The use of gradient and Laplacian of temperature is introduced as a means of increasing defect contrast and mitigating heater variation.

The study aimed to identify deterioration problems, repair and conservation needs of andesites on the walls of the Ankara Castle. Decay forms of walls were documented by visual examination. Samples taken from the surface of the weathered andesites were examined for their basic physical, mechanical compositional and minerological properties. The bulk density and total porosity were determined as basic physical properties. The mechanical properties were expressed as ultrasonic velocity and modulus of elasticity (Emod). Compositional and mineralogical properties were determined by optical microscopy and XRD analyses. Soluble salt content of the andesite samples was determined by spot tests of anions and electrical conductivity measurements. Findings were evaluated in terms of the long-term weathering behaviour of andesites under the effect of the prevailing climate, air pollution problems of Ankara, dampness problems of the structure, previous repairs with incompatible cement mortars. The surfaces of Ankara Castle andesite blocks were heavily weathered. The results were compared with the physical and mechanical properties of fresh andesites from G&ouml / lbaSi-Ankara quarry. The surface of the andesite blocks at the Ankara Castle, had low bulk density and high porosity, low ultrasonic velocity and low Emod values. Thin section and XRD analyses supported those results by revealing the presence of physical and chemical weathering on feldspars and other main minerals of andesite, as well as the presence of amorphous minerals at the surface.

Thesis (MEng in Test and Evaluation)--University of South Australia, 1995

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 84-86). Also available via the Internet.

Thesis (MEng) - Swinburne University of Technology, Industrial Research Institute Swinburne - 2007. / A thesis submitted for fulfillment of the requirement for the degree of Master of Engineering, Industrial Research Institute, Swinburne University of Technology - 2007. Typescript. Includes bibliographical references (p. 168-193).

Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2009. / Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Vita. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Graphite bricks make up a significant part of the core of an Advanced Gas-cooled Reactor (AGR). The graphite moderates the neutrons vital to the continuation of the fission chain reaction and provides support and stability for the entire core. During operation, the graphite can be oxidised due to the extreme conditions inside the core and so undergo weight loss. Differential shrinkage caused by neutron interaction throughout the brick can also cause radial cracking to occur. The effects of the oxidation, weight loss and cracking reduce the ability of the graphite to function as a moderator. The effects also have the potential of reducing the structural integrity of the brick, causing movement and structural instability of the entire core. It is, therefore, vital to monitor the condition of the graphite bricks and to understand how the changes in the graphite's properties and structure may affect the safe operation of the reactor. This report firstly looks briefly at the effect of irradiation on the graphite brick; the mechanisms leading to weight loss and cracking. The report then considers various methods which can be used to inspect the deterioration of graphite blocks within the cores of AGRs deriving quantitative and qualitative information on density and crack profiling. These methods will be considered for use both on small samples trepanned from the core and in-situ blocks within the reactor core, requiring non-destructive techniques. The inspection methods considered in this report are: Electrical Impedance Tomography (EIT); Four point probes; Eddy Current Tomography; and Electromagnetic Inductance Tomography (EMT).There are two main contributions of this thesis. First, the development an EIT methodology using outward facing probes, which were best suited to the geometry of the graphite bricks within the AGR. Proof of principle was established using both modelling and laboratory testing. The second contribution is the development of commercial grade EMT equipment, which can be used on-site to determine the conductivity of trepanned samples. The method was successfully demonstrated in the laboratory; however, further development will be required for use on-site, due to the sampling speed required.

Terahertz source technology has been an active area of research for a number of years. This has helped develop continuous wave solid-state sources that are highly desirable in a wide range of applications spanning from Earth science to medical science. However, even with advances in terahertz technology, the generation of fundamental source power at these frequencies is still challenging. Promising electronic solid-state devices fall short in overcoming source power shortage due to electronic breakdown mechanism and fabrication limits at terahertz frequencies. The fundamental physical limitation of photonic devices, such as low photon energy, force cryogenic operation which at times is impractical. Schottky diode frequency multipliers often offer a very practical solution for generating continuous wave radiation based on solid-state technology. This harmonic source technology is today a most certain candidate for many applications where compactness and room temperature operation is desired. However, despite of all the advances in Schottky diode fabrication and their use in frequency multiplication, output power falls rapidly with increasing frequency. Thermal constrains, fabrication limits, assembly errors and parasitic losses all constitute changes that affect the performance of these devices and make it difficult to reproduce experimental data. To overcome these problems and progress towards the generation of milliwatts of power at terahertz frequencies, the study of existing methods to generate and handle high power is necessary. In the first part of the thesis, the design, fabrication and development of two Schottky diode-based frequency doublers is discussed. The work focuses on the generation of high-power sources that are capable of handling higher input powers while maintaining good thermal efficiencies. A detailed study into the machining tolerances, assembly errors and temperature effects are evaluated for the frequency doublers. High frequency effect such as velocity saturation is also addressed. Depending on the design frequency and power handling, two different circuit configurations are employed for the frequency doublers. While the high-power 80/160 GHz frequency doubler used a discrete flip-chip diode configuration, the 160/320 GHz frequency doubler employed an integrated diode membrane to mitigate sensitivity issues encountered during assembly and enable correlation between simulated and measured data. The second part proposes the use of millimeter-wave Schottky diode-based radiometers for imaging of composites samples. The focus of this experiment is the introduction of an alternate EM inspection method with the use of broadband Schottky diode components. This technique combines two different fields {--} non-destructive testing and radiometry, which presents a potentially new and interesting area for research. Since no single method can qualify to be the most accurate for all inspections, and with the future integration bringing down manufacturing costs of high frequency components, this demonstration presents a new approach to consider for future material imaging and evaluation experiments.