Secondary Radiation Influence on LSF Shapes in Radiography

A radiographic image is generated by both primary and secondary radiations. In a previous study [1, 2] the influence of secondary radiation on the generated image was shown for square based blocks of finite dimensions (few mean free paths). The response to a step change in the block’s thickness, varies drastically with the step location relative to the block’s edges [3]. However, even when the radiographed object is large and the step response is studied far off the object’s limits, the effect of the secondary radiation is still significant. This radiation distorts the “ideal” step response shape expected from the primary radiation

Characterization of Moment of Inertia Variations by Holographic Interferometry

Holographic interferometry (HI) is a powerful tool for mapping of surface defects. In conjunction with various stressing techniques [l–4], it offers an NDT tool for the detection of flaws within the volume of materials. The method is advantageous for integrity characterization of components to serve under mechanical stress, where the detailed shape, size and depth of the flaw within the material are of no interest. For most applications, where integrity is tested, the moment of inertia may be used as a measure for classification of the product and for the estimation of its reliability. The presence of volumetric flaws, when the sample is under loading, is expressed in the holographic interferogram. The exterma of the fringe pattern are used for determination of the displacement distribution. The second derivative of the displacement distribution is related to the bending moment and the moment of inertia. The moment of inertia may be further processed to obtain a function free from degrading influence of the specific measuring system employed [5]

Applications of Film Tomography Technique for QNDE

Tomography with X- and gamma- rays provides three-dimensional radiographic information on the examined object. The film-based tomography (1,2) generates a summation-image of a surface within the object by continuously combining back projections directly on the film. This method has many attractive features for industrial applications in which cost and simplicity are of primary importance. Some of the features are: (1) The absence of post processing allows this method to yield an image immediately on development of the film.; (2) Conventional radiologists need a short training time to master the technique as most components and concepts are familiar to them: e. g. radiation sources, films, screens, collimators, filters, processing units, viewers, exposure, contrast, resolution.; (3) Purpose oriented system optimized for a certain range of products, may be built with costs much less than digital computing trans-axial tomography (CT).; (4) Tomographic images of surfaces of critical areas within the examined object are directly recorded on films curved to match the required shape.; (5) Tomographs on film may be digitized and imaged-processed by commercial system developed for conventional radiographs.; (6) The slice thickness of the recorded surface may be in the order of magnitude of the thickness of the film-emulsion.; (7) The quality of the tomograph is high especially for high- contrast objects (2) and whenever the noise and the dynamic-range of the film do not impose a limitation on the information to be extracted.</p

Non Linear Correlation between Statistically Sensitive Ultrasonic Features and the Strength of Composite Adhesive Joints

The motivation for the increasing use of fiber-reinforced materials as structural components in the aeronautical and automobile industries is their improved strength to weight ratio. The most widely used technique for the joining of composite components is adhesive bonding. However, the use of bonded composite joints has been hampered by the lack of a reliable nondestructive testing (NDT) technique for the evaluation of the interfacial condition of the joints, which has an essential role in establishing the joint strength

Material Density Distribution of a Radial Symmetric Product from a Single X-Ray Radiograph

X-ray digital tomographic methods may be classified according to the number of projections and the angular coverage required to obtain the density distribution of the object under study. At one extremity stands computerized tomography which employs multiple projections and wide angular coverage (± π). At the other extremity stand reconstruction methods employing a single projection. As the number of projections decreases, the information provided for the reconstruction becomes more incomplete. The decrease in the information content may sometimes be compensated by the use of a priori knowledge about the product and thus alleviate to some extent the ill-posedness of the problem [l–4]

Applications of Film Tomography Technique for QNDE

Tomography with X- and gamma- rays provides three-dimensional radiographic information on the examined object. The film-based tomography (1,2) generates a summation-image of a surface within the object by continuously combining back projections directly on the film. This method has many attractive features for industrial applications in which cost and simplicity are of primary importance. Some of the features are: (1) The absence of post processing allows this method to yield an image immediately on development of the film.; (2) Conventional radiologists need a short training time to master the technique as most components and concepts are familiar to them: e. g. radiation sources, films, screens, collimators, filters, processing units, viewers, exposure, contrast, resolution.; (3) Purpose oriented system optimized for a certain range of products, may be built with costs much less than digital computing trans-axial tomography (CT).; (4) Tomographic images of surfaces of critical areas within the examined object are directly recorded on films curved to match the required shape.; (5) Tomographs on film may be digitized and imaged-processed by commercial system developed for conventional radiographs.; (6) The slice thickness of the recorded surface may be in the order of magnitude of the thickness of the film-emulsion.; (7) The quality of the tomograph is high especially for high- contrast objects (2) and whenever the noise and the dynamic-range of the film do not impose a limitation on the information to be extracted.</p