Eddy current techniques have been widely used in the NDE inspection of aircraft engine components. Depending on the flaw characteristics and specimen composition, various EC probe designs have been employed to achieve the maximum probability of detection (POD). Traditionally, the effectiveness of a probe design for a given inspection is determined experimentally. In particular, parameterssuch a...

Excellent progress in the development of Submillimeter-wave SIS and HEBmixers has been demonstrated in recent years. At frequencies below 800 GHz these mixers are typically implemented using waveguide techniques, while above 800 GHz quasi-optical (open structure) methods are often used. The choice of waveguide offers several advantages over quasi-optical techniques, such as the use of broadband...

A structurally supportive miniaturized low-weight (≤150 g) radiofrequency switch mode amplifier developed to power the small diameter Pocket Rocket electrothermal plasma micro-thruster called MiniPR is tested in vacuum conditions representative of space to demonstrate its suitability for use on nano-satellites such as “CubeSats.” Argon plasma characterization is carried out by measuring the opt...

In recent years, considerable attention has focused upon the biological applications of the atomic force microscope (AFM), and in particular in its ability to explore biomolecular interaction events at the single molecule level. Such measurements can provide considerable advantages, as they remove the data averaging inherent in other biophysical/biochemical approaches that record measurements o...

in this study, plasma electrolytic oxidation of 2024-t3 aluminum alloy was investigated. the electrolyte used in this investigation was an alkaline solution containing additives of silicate, phosphate, potassium hydroxide and glycerin. a conventional dc power source with a low applied voltage was employed. corrosion resistance of the oxide layer was investigated by means of tafel plots and elec...

The effect of evanescent mode generation, due to geometrical mismatch, in acoustic impedance measurements is investigated. The particular geometry considered is that of a impedance probe with an annular flow port and a central microphone, but the techniques are applicable to other geometries. It is found that the imaginary part of the measured impedance error is proportional to frequency, and t...

Eddy current induced in a metal by a coil carrying an alternating current may be perturbed by the presence of any macroscopic defects in the material, such as cracks, surface indentations, or inclusions. In eddy-current nondestructive evaluation, defects are commonly sensed by a change of the coil impedance resulting from perturbations in the electromagnetic field. This paper describes theoreti...