Hard magnetic material measurements in a pulsed field magnetometer considering coating and eddy current effects

Rare-earth permanent magnets are coated in order to avoid corrosion. When considering the rated geometrical properties of a sample, the coating thickness has to be known precisely as it wrongly enlarges the magnetically active volume which in turn affects the accuracy of the measured magnetic properties. In this work, the sensitivity of hard magnetic material property measurements regarding the consideration of different coating thicknesses is evaluated. Moreover, the impact of eddy current effects on the magnetic properties is studied when measuring in an open circuit. Additionally, an outlook for a measurement-based determination of the electric conductivity of permanent magnet samples is given

A New Approach to Measure Fundamental Microstructural Influences on the Magnetic Properties of Electrical Steel using a Miniaturized Single Sheet Tester

Magnetic properties of electrical steel are usually measured on Single Sheet Testers, Epstein frames or ring cores. Due to the geometric dimensions and measurement principles of these standardized setups, the fundamental microstructural influences on the magnetic behavior, e.g., deformation structures, crystal orientation or grain boundaries, are difficult to separate and quantify. In this paper, a miniaturized Single Sheet Tester is presented that allows the characterization of industrial steel sheets as well as from in size limited single, bi- and oligocrystals starting from samples with dimensions of 10x22 mm. Thereby, the measurement of global magnetic properties is coupled with microstructural analysis methods to allow the investigation of micro scale magnetic effects. An effect of grain orientation, grain boundaries and deformation structures has already been identified with the presented experimental setup. In addition, a correction function is introduced to allow quantitative comparisons between differently sized Single Sheet Testers. This approach is not limited to the presented Single Sheet Tester geometry, but applicable for the comparison of results of differently sized Single Sheet Testers. The results of the miniaturized Single Sheet Tester were validated on five industrial electrical steel grades. Furthermore, first results of differently oriented single crystals as well as measurements on grain-oriented electrical steel are shown to prove the additional value of the miniaturized Single Sheet Tester geometry

Evaluation of dynamic participation in portuguese active employment programmes

Over the past decades, European labour market policies, like the Portuguese, offer not only a set of simultaneous active programmes, to the universe of unemployed registered individuals, but also the possibility of successive participation in different active programmes. Such dynamic participation patterns have as a consequence different average causal effects to participants. Aware of this reality, the present paper discusses how to overcome the limitations of the traditional labour market microeconometric evaluation literature, eminently static, to empirically estimate the impact of dynamic selection. In recent years it is possible to report several developments concerning the introduction of dynamic elements in the traditional evaluation econometric models. For instance, is important to report that causal effects of dynamic sequences make use of potential results and allow the introduction of intermediate results which determine subsequent sequences. The application presented in this research study uses an administrative dataset containing extensive individual information concerning the active public intervention on the Portuguese labour market. Based on this dataset, it will be shown that it is possible to make a quantitative analysis on the impact participation of an unemployed individual on a sequence of active measures offered by the unemployment office services. The present empirical study analyses the power of the dynamic nonparametric model as a fundamental tool of an active labour market policy evaluation, and allows, even if in an exploratory way, the evaluation of the consequences of sequential participation. Indeed, based on propensity score matching microeconometric evaluation techniques it is possible to compute the causal effect of the decision to postpone participation in an active labour programme, vis-à-vis the decision of consecutive labour programme participation, on the one hand, and continuous non-participation, on the other. The evaluation results of a consecutive participation decision in comparison with the alternative of non-participation or postponed participation suggest a low degree of effectiveness by the Portuguese public intervention in the labour market. Moreover, the empirical application of a dynamic propensity score methodology seems to be a quite useful tool for the estimation of dynamic causal effects when the effectiveness of a sequence of participation decisions is tested compared to a distinct sequence of decisions