Abstract: A multi-level compensation is used to compensate for environment and operational condition changes in ultrasonic testing of structures. A phase-shifting (time-domain) compensation is utilized to compensate for changes in operating temperature of a structure between acquisition of baseline and monitoring measurements. A frequency-filtering (frequency-domain) compensation is utilized to compensate for liquid-boundary effects (i.e., effects caused by static and/or dynamic liquid presence within the structure) during acquisition of baseline and monitoring measurements. The multi-level compensation addresses amplitude changes, time shifts, and frequency content variations in ultrasonic measurements due to temperature changes and acoustic interaction with liquid presence within the structure, and increases the accuracy of ultrasonic testing.

Abstract: Methods and apparatus are disclosed for assessment of microstructural defects in a large structure. Third order elastic constants engender nonlinear excitation of acoustic modes particularly at points of local stiffness changes or stress concentration such as ends of microcracks. A broadband multimode acoustic signal is transmitted through an interrogation region from a first transducer, whereby a second transducer receives an acoustic signal containing linear and nonlinear components. Linear terms are canceled, and a magnitude of the nonlinear acoustic response is measured using time-resolved spectral analysis, to determine a coefficient for acoustic nonlinearity of the interrogation region that serves as a qualitative or quantitative representation of microcrack damage. Broadband signals avoid mode-specific effects such as shadowing or phase mismatch. Damage location can be identified by region or time-of-flight.

Abstract: An electrochemical cell that oxidizes a solution provides a continuous and stable supply of an oxidizing ion solution to a fixture or vessel used for the purposes of decontaminating metal and metal alloys. The electrochemical cell includes an anode compartment that oxidizes the solution in nitric acid or methane sulfonic acid at a rate equal to or greater than a rate of reduction, or generates the oxidizing ions prior to use in a batch. The electrochemical cell is part of a larger system that facilitates online measurement system which measures the oxidizing ion solution and the dissolved PuO2, UO2, AmO2, other radionuclides, or other contaminates in real-time. Solution decontamination system removes the dissolved PuO2/UO2/AmO2, other radionuclides, or other contaminates from the oxidizing ion solution, real time acoustic monitoring of the thickness of the surface being contaminated, and automation of a delivery system facilitates flow between surface and electrochemical cell.

Abstract: Acoustic transducers generate and receive acoustic signals at multiple locations along a surface of rigid structure, wherein longitudinal spacing between transducer locations define measurement zones. Acoustic signals with chosen amplitude-time-frequency characteristics excite multiple vibration modes in the structure within each zone. Small mechanical changes in inspection zones lead to scattering and attenuation of broadband acoustic signals, which are detectable as changes in received signal characteristics as part of a through-transmission technique. Additional use of short, narrowband pulse acoustic signals as part of a pulse-echo technique allows determination of the relative location of the mechanical change within each zone based on the differential delay profiles. For accurate acoustic modeling and simulation, the mesh size, time step, time delay, and time-window size are optimized.

Abstract: Acoustic transducers generate and receive acoustic signals at multiple locations along a surface of rigid structure, wherein longitudinal spacing between transducer locations define measurement zones. Acoustic signals with chosen amplitude-time-frequency characteristics excite multiple vibration modes in the structure within each zone. Small mechanical changes in inspection zones lead to scattering and attenuation of broadband acoustic signals, which are detectable as changes in received signal characteristics as part of a through-transmission technique. Additional use of short, narrowband pulse acoustic signals as part of a pulse-echo technique allows determination of the relative location of the mechanical change within each zone based on the differential delay profiles. For accurate acoustic modeling and simulation, the mesh size, time step, time delay, and time-window size are optimized.