Lithological and pedological influences on the magnetic susceptibility of soil: their consideration in magnetic pollution mapping

Magnetic susceptibility measurements are widely used to map and monitor the heavy metal pollution of soils. However, the magnetic properties of soils are influenced significantly by the bedrock lithology and soil-forming processes. Therefore, a main challenge in the data interpretation is to filter out the anthropogenic pollution signal. In this study we address this problem by analysing susceptibility values, heavy metal concentrations, as well as pedological parameters in a large soil data set from the eastern segment of Austria, covering a wide range of different lithologies and soil types. The statistic assessment demonstrates an influence of lithology and soil type on the magnetic susceptibility signal. Therefore anomalies are defined in sub sets of different soil types separately. Three different methods were applied to detect susceptibility anomalies: the median absolute deviation method, the boxplot method, and the population modelling method. These methods evaluate topsoil data only and can therefore also be applied to field measurements of magnetic susceptibility. The results were compared to the conventional method of calculating the difference of topsoil and subsoil susceptibility. All three approaches identify the main anomalies in the study area and are successful in circumventing the problem of erroneous anomaly definition due to pedological processes. However, knowledge of the lithological background is still necessary for a meaningful interpretation and can only be substituted by a large amount of data. The tested methods lead to thresholds of different height and therefore act as filters of different strength for the definition of anomalies.     

Luft

Ohne Zusammenfassung     

Allgemeine analytische Methoden und Apparate

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High Temperature Oxidation Resistance of CrAlYN-Coated Ti45Al8Nb

The oxidation behaviour of Cr_0.45Al_0.53Y_0.02N (at.%) thin film deposited on ??-TiAl based alloy Ti?C45Al?C8Nb (at.%) was carried out. The tests were performed in the temperature range 750?C950???C for 500?h. The materials showed good corrosion resistance only at temperatures of 750 and 850???C where Al₂O₃ and Cr₂O₃ phases developed as a top oxide scale. A lack of corrosion resistance was observed at 950???C where a thick scale (100???m) that developed consisted of alternate layers of TiO₂ and Al₂O₃ phases. To investigate the oxidation behaviour, the corrosion kinetics were determined by means of discontinuous gravimetry of the exposed samples. Surface and cross-sectional analyses of exposed samples were conducted using scanning electron microscopy (SEM) and energy X-ray dispersive spectroscopy (EDS).     

Dr. Dr. h. c. Kurt Lindner zur Vollendung des 70. Lebensjahres

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Composition,microstructure and mechanical properties of boron containing multilayer coatings for hot forming tools

The tribological conditions of hot forming processes are much different from those at room temperature. Thus classical wear-resistant coating like CrN, CrAlN, TiAlN in most cases are not sufficient for hot forming tools in industrial applications.Additionally the use of lubricants is limited, thermal shock conditions and the increase of sticking work piece material are leading to severe wear.This paper presents examples for ternary boron based Ti–B–N gradient coatings in specific multilayer designs obtained through plasma enhanced chemical vapor deposition. After a thorough characterization of the chemical composition by Auger electron spectroscopy, the microstructure by X-ray diffraction and the mechanical properties by microindentation and small-angle cross section nanoindentation, the coatings were applied onto hot forming tools made from DIN 1.2367 tool steel. The coated tools were tested in hot forging of AISI 1043 raw parts in an automatic press and have been compared in terms of adhesion and wear resistance. In this study an optimum design has been found which significantly reduces sticking of work piece material and wear. This allows an efficient production without interruptions for a reworking of the tools and enables to increase the process reliability paired with a longer tool life.     

Referate

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A SINGULAR INTEGRAL EQUATION SOLUTION FOR THE LINEAR ELASTIC CRACK OPENING DISPLACEMENT OF AN ARBITRARILY SHAPED PLANE CRACK: PART II REGULAR INTEGRAL SOLUTIONS

Abstract— The boundary value problem for an arbitrarily shaped plane crack embedded in a 3D linear elastic solid can be reduced to a governing hyper-singular integral equation. A discretizing procedure based on a triangulation of the crack area has been offered in Part I of this work. The main goal of Part I is to introduce the analytical results for the 18 resulting finite-part integrals defined over a triangular mesh area. The finite-part integrals occur in those triangles where the source point coincides with one of the element nodes. Mostly the source point lies outside of the considered triangle. In these cases the occurring area integrals are regular.
The aim of Part II is, therefore, the derivation of the closed form expressions for the relevant 18 regular area integrals. The resulting relations are of algebraic form which can easily be coded in compact form. Their numerical proof by two different methods shows the highest accuracy and, therefore, the correctness of the final solutions. The relevant numerical results are offered in Appendix I.
With the formulae provided in Part I and Part II of the paper the determination of the coefficient matrix, necessary for the calculation of COD values from a linear equation system, is precise and needs only minimum computer time.     

Mechatronische Modellierung und Simulation der Dynamik von Walzanlagen

Rolling mills represent mechatronic systems with high complexity. As the dynamic behavior of a mill is crucial for its performance, dynamic simulation models are indispensable today for evaluating concepts for revamp and new design. Through modularization of the simulation model the high complexity can be mastered and flexibility of the total simulation model is achieved.