The application of a recent field theory of deformation and fracture to nondestructive testing (NDT) is discussed. Based on the principle known as the symmetry of physical laws, the present field theory formulates all stages of deformation including the fracturing stage on the same theoretical basis. The formalism derives wave equations that govern the spatiotemporal characteristics of the differential displacement field of solids under deformation. The evolution from the elastic to the plastic stage of deformation is characterized by a transition from longitudinal (compression) wave to decaying longitudinal/transverse wave characteristics. The evolution from the plastic to the fracturing stage is characterized by transition from continuous wave to solitary wave characteristics. Further, the evolution from the pre-fracturing to the final fracturing stage is characterized by transition from the traveling solitary wave to stationary solitary wave characteristics. In accordance with these transitions, the criterion for deformation stage is defined as specific spatiotemporal characteristics of the differential displacement field. The optical interferometric technique, known as Electronic Speckle-Pattern Interferometry (ESPI), is discussed as an experimental tool to visualize those wave characteristics and the associated deformation-stage criteria. The wave equations are numerically solved for the elastoplastic stages, and the resultant spatiotemporal behavior of the differential displacement field is compared with the experimental results obtained by ESPI. Agreement between the experimental and numerical results validates the present methodology at least for the elastoplastic stages. The solitary wave characteristics in the fracturing stages is discussed based on the experimental results and dislocation theory.

This paper discusses a non-destructive measurement technique of residual stress through optical visualization. The least amount of deformation possible is applied to steel plates by heating the specimens +10 °C from room temperature for initial calibration, and the thermal expansion behavior is visualized with an electronic speckle pattern interferometer sensitive to two dimensional in-plane displacement. Displacement distribution with the thermal deformation and coefficient of thermal expansion are obtained through interferometric fringe analysis. The results suggest the change in the thermal deformation behavior is affected by the external stress initially applied to the steel specimen. Additionally, dissimilar joints of steel and cemented carbide plates are prepared by butt-brazing. The residual stress is estimated based on the stress dependence of thermal expansion coefficient.

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We present a simple design of a balloon-borne infrared spectral photometer that can be built and used by undergraduate students to perform an experiment demonstrating the atmospheric greenhouse effect. The experiment demonstrates that the Earth radiates heat to space in the infrared region but that the radiation at the top of the atmosphere has a much lower effective radiation temperature than at the surface of the Earth, which is the essence of the greenhouse effect. The experiment also demonstrates that the greenhouse effect is much more pronounced in molecular absorption bands than in the so-called infrared window. The thrill of putting together a balloon experiment aside, students performing this experiment also gained experience in practical applications of Planck's law.

Numerical studies have been conducted based on the recently published Deformation Field Theory. Effects of pulling rates on displacement waves and volume expansion waves are analyzed in a finite element model (FEM) of a solid experiencing a uni-axial tensile load. Without relying on empirical data, the model's numerical results demonstrate empirically known concepts that a fracture occurs more easily when the pulling rate is high, and the direction of external load is reversed.