NDE of microstructured materials by x-ray diffraction and refraction topography
For the purpose of micro structural characterization X-ray topography reveals the spatially resolved scattering of materials and small components. It combines the advantages of radiographic imaging and the analytical information of wide and small angle X-ray scattering like phase distribution, texture, micro cracks, interfaces and pores. Scanning techniques at selected scattering conditions permit the topographic characterization of any crystalline or amorphous solid or liquid. Topographic methods and applications for the purposes of research, quality control and damage evaluation are presented.
STRUCTURE ASSESSMENT BY X-RAY DIFRACTOMETRY FOR CERAMIC MATERIALS USED IN ORAL PROSTHETIC SYSTEMS
The paper presents a difractometric analysis on two types of ceramics nowadays available on the market and frequently used in restorative dentistry: InLine (IVOCLAR) and Hera-Ceram (HAEREUS KULZER). The diffractograms obtained by projecting the x-ray beam on the ceramic surface allowed establishing the structural characteristics that could influence the tribological behaviour of certain ceramic materials by determining the crystalline parameters and/or amorphous network and correlate the results to the wear coefficient values of the concerned materials. This non-destructive method that characterise materials’ structure establishes several correlations between the macroscopic properties and their atomic structure.
In search of optimum chest radiography techniques.
A nation-wide study of chest radiography in Sweden had previously revealed a large variation in the physical and technical factors involved, in particular the radiation dose. In this study the image quality could not be assessed unambiguously. The aim of the present study was to try to establish a correlation between visual grading of radiographs and physical and technical factors in order to find the optimum chest X-ray system. The physical and technical performance of 24 chest units was evaluated. Radiographs were taken of an anthropomorphic chest phantom supplied with test structures simulating various pathologies. Image quality was assessed by visual grading analysis of the radiographs. The physical and technical parameters of the units rated best were used to exemplify good radiographic practice. The results were in agreement with the recommendations issued by the Commission of the European Communities (CEC). It was also shown that low radiation dose is compatible with high-quality radiographic imaging of the chest.