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Visual inspection is useful for detecting delaminations at the surface and edges of materials. However, a visual inspection may not detect delamination within a material without cutting the material open. Tap testing or sounding involves gently striking the material with a hammer or hard object to find delamination based on the resulting sound.
The notion of acoustic microscopy dates back to 1936 when S. Ya. Sokolov [1] proposed a device for producing magnified views of structure with 3-GHz sound waves. However, due to technological limitations at the time, no such instrument could be constructed, and it was not until 1959 that Dunn and Fry [2] performed the first acoustic microscopy experiments, though not at very high frequencies.
Potentiometry passively measures the potential of a solution between two electrodes, affecting the solution very little in the process. One electrode is called the reference electrode and has a constant potential, while the other one is an indicator electrode whose potential changes with the sample's composition. Therefore, the difference in ...
Dye penetrant inspection (DP), also called liquid penetrate inspection (LPI) or penetrant testing (PT), is a widely applied and low-cost inspection method used to check surface-breaking defects in all non-porous materials (metals, plastics, or ceramics).
Delamination is a likely source for the heat pulses. [3] The tectonic development of collapsed mountain belts is heavily debated. Some argue that delamination causes a second uplift along with crustal thickening, heating and volcanism. Others argue that delamination causes collapse and thinning of the crust.
Standard electromagnetic induction utility locating tools require utilities to be conductive. These tools are ineffective for locating plastic conduits or concrete storm and sanitary sewers. Since GPR detects variations in dielectric properties in the subsurface, it can be highly effective for locating non-conductive utilities.
They can also be used as transduction elements, converting the output of another sensor, which generates a strain or temperature change from the measurand, for example fiber Bragg grating gas sensors use an absorbent coating, which in the presence of a gas expands generating a strain, which is measurable by the grating.
With advances in instrumentation, processing and modelling, magnetotellurics has become one of the most important tools in deep Earth research. Since first being created in the 1950s, magnetotelluric sensors, receivers and data processing techniques have followed the general trends in electronics, becoming less expensive and more capable with ...