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- Hydrogen assisted cracking (2)
- Maintenance (2)
- Ultrasound (2)
- Antenna (1)
- Band shape analysis (1)
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NDT of Concrete Structures
(2002)
VDI/VDE-Guideline 5570 - The First Comprehensive Standard on Characterization and Testing of POF
(2002)
Introduction
Due to the long history of railroad companies around the world, varying means of examination according to the specifications for the different railroad components have been carried out based on the general industrial progress of the country [1-3]. For more than 50 years the application of customized ultrasonic techniques for the examination of railroad components has increased, in comparison to conventional ultrasonic techniques used until to the end of 20th century. In this traditional atmosphere some accidents have disturbed the silent harmony of companies involved in the production of critical parts. More than ever high speed modern trains require modern and advanced examination techniques [4-8]. For practical application new ultrasonic techniques have been developed and optimized in co-operation with the German Railroad Company. In the present contribution the inspection of railroad axles will be described. The ultrasonic technique used for the examination is the phased array technique. The optimization of the phased array probes for the different geometries of the axles given was completed using a computer model for directivity calculations. In relation to the limited accessibility between wheel and brake angles of incidence for shear waves in the range between 28° and 72° are necessary.
During the examination of the axles a a considerable amount of ultrasonic data must be stored (storage of the digitized A-scans). However, due to economic aspects the evaluation of this data should be carried out in a very short time. The whole examination of one axle should not exceed 5 minutes. Therefore we have developed a special evaluation program adapted to the particular problematic of the axle inspection. The build up of the whole inspection system was done with partners from the industry like Krautkramer and a division of the Research Department of the Deutsche Bahn AG. In this consortium the Research Department of the Deutsche Bahn AG was responsible for the specification of the inspection problem, Krautkramer for the organization of the whole technical follow up and BAM for the development and optimization of the ultrasonic inspection technique as well as for the evaluation software. Some examples concerning the optimization process will be described in the present contribution.
Nowadays, micro-x-ray fluorescence analysis has become an established tool for the non-destructive investigation of art objects. However, as these types of sample often forms complex and inhomogeneous layer systems, the quantitative evaluation of the measurements is far from a standard routine. In this paper a fingerprint model is described, which we developed to discriminate between different iron-gall inks of historical manuscripts or compositions. Fundamental parameter methods are used to take self-attenuation, interference from the paper background and diffusion of the ink into the paper into account. The capability of the method to contribute to the solution of archaeometric problems is exemplified by the investigation of an ancient composition. Finally, the restrictions of the model and possible improvements are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Apparently that the type testing procedure should be conducted under the conditions ensuring reproducibility of its outcomes. We investigated various factors effecting upon the reproducibility. To obtain quantitative characteristics of indications visibility the image-processing hard-and software were used. It was established that there are two main groups of these factors. The first depends on the differences between various test panels, which are used for type testing. The second one concerns the reproducibility of some stages of penetrant testing procedure (excess penetrant removing and developer application). The recommendations to increase the reproducibility of type testing are developed and illustrated experimentally.
The determination of penetrant system sensitivity as a part of type testing should be conducted ensuring reproducibility of the result. We investigated some factors effecting the reproducibility. To obtain quantitative characteristics of indications visibility, an image processing system was used [1]. We used 3 different sets of reference blocks (rb1, rb2, rb3) corresponding to type 1 of EN ISO 3452-3 [2]. Two fluorescent penetrants with different sensitivities and the same wet solvent developer were used.
It was established that the reproducibility of type testing is influenced by mainly two principal factors. First there are the differences between reference blocks. Second one concerns the reproducibility of penetrant testing procedure, especially excess penetrant removal and developer application.
According to EN ISO 3452-3 a reference block for determination of sensitivity level of fluorescent penetrants consists of a set of three nickel-chrome plated panels with 10, 20 and 30 µm plating thickness. Transverse cracks are made in each panel by stretching the panels in the longitudinal direction and width to depth ratio of the cracks should be approximately 1/20. Each panel presents a certain sensitivity level, which is characterised by the level of visibility of the indication. The highest level 3 corresponds to the panel with 10 µm thickness plating. Each panel is cut longitudinally (perpendicular to the crack) so that 2 sheets (panels A and B) with nearly the same cracks will be produced. These panels A and B of a reference block are used for relative evaluation, for example to compare sensitivities of two penetrants. It is considered that the application of the same penetrant to both panels with subsequent adequate development results in the same visibility of the indications on these panels.
Quantitative correlations between the abilities of the reference blocks used for determining of the sensitivity were obtained in our investigations. We used the relations between the measured values of light-fluxes from the indications of similar comparing areas on two panels. These indications correspond to certain cracks parts of the same total length on both comparing areas. The relations of the steps between the panel are responsible for the definition of the sensitivity groups. From our investigations it follows that the steps of the different sets are different. Besides it was established that the indications visibility for the same penetrant applied on different reference blocks might have a considerable difference depending on the penetrant sensitivity: the higher penetrant sensitivity, the smaller is such a difference between the steps 30/20 and 20/10. For example, for rb3 the relations 30/20 and 20/10 for lower sensitive penetrant (I1) reached factor 3 comparing with factor 2 for higher sensitive penetrant (I2).
Some results of the comparison between the 3 sets (rb1, rb2, rb3) investigations are summarised in Table 1 with rb1 as a reference.
Model for inhomogeneous ink paper layer systems measured with micro X-ray fluorescence analysis
(2002)
Development of wood-inorganic composites with enhanced properties and environmental stability
(2002)
A consortium has recently been initiated to study the macroscopic and microscopic properties of basaltic and andesitic rocks as analogue materials for Mars. The goal of this project is the integration of diverse spectroscopic approaches to
evaluate the composition and texture of Mars materials using both in situ and remote sensing techniques. Initial emphasis is placed on assessment of the mineral composition for low albedo areas (basalt vs andesite vs weathering) of the Martian surface through spectral analysis of a suite of samples that have been exceptionally well characterized in the laboratory. The initial results indicate that the visible/NIR reflectance spectra, mid-IR reflectance and emission spectra, and Mössbauer spectra contain consistent diagnostic features associated with the measured modal mineralogy and provide baseline data for the first group of well characterized basalts. The consortium study involves integrating multiple remote sensing techniques for recent and upcoming missions to Mars in order to compare the results obtained by these instruments and thereby strengthen interpretive results.