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Although in the past complicated and often considered ‘exotic’ process, hot stamping of steel is now widely used in the automotive industry and for some safety components it becomes obligatory. The hot stamped parts are used in regions where very high strength is required. But for some applications also ductility needs to be incorporated in parts to guide the absorption of energy under crash loading, for other the material thickness has to be reduced smoothly due to lightweight. This will be achieved by tailoring the material properties within the component. This new generation of hot formed parts is already standard in the market, but still difficult in the engineering. And the next one is already in start position – aluminum warm forming is planned as a substitution of the heavier steels for structural parts, but newly also for outer panels, where they have to fulfil all requirements on visible parts. Light, strong, accurate, high quality and warm formed to improve the formability of the material. This paper describes successful engineering methods in virtual hot stamping process with tailored properties and of warm and hot formed aluminum parts. [ABSTRACT FROM AUTHOR]

In this paper the fault diagnosis of multiple faults in linear circuits is studied for distortion analysis for 2nd and 3rd harmonic components by considering a state variable filter circuit. To study the testability of the circuit the distortion analysis is plotted for various fault conditions. The sensitivity of the output signal with respect to the faults along with pole-zero analysis is obtained. The transfer function of the state variable filter considered for the analysis is given by: [ABSTRACT FROM AUTHOR]

This letter briefly presents an interesting set of results from a non-destructive magnetic measurement method named as the distortion analysis of magnetic excitation (DAME). The time derivative of the excitation voltage ( V E ) across the coil around the electromagnetic (EM) yoke plotted as a function of total applied voltage ( V T ) (named as the DAME profile) truly reflects the magnetisation behaviour of the ferromagnetic material introduced between the poles of the EM yoke to close the magnetic flux path. The shape of the DAME profile with a peak and trough clearly reflects the subtle changes in the composition, microstructure, grain orientation and stress through their effect on the magnetisation process in the ferromagnetic material placed between the poles of the EM yoke. This letter shows that the DAME profile measurement is a simple non-destructive evaluation (NDE) method to detect and determine variations in the properties of ferromagnetic materials and has tremendous potential for several applications related to the evaluation of ferromagnetic materials and components. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new and accurate experimental method for determining resonant frequencies of MEMS. [•] The method is based on harmonic distortion analysis of MEMS electrical voltage output. [•] Development of electrostatic energy harvesters as test samples. [•] Comparison with measurements carried out by DLTS system are presented. [•] An uncertainty as low as one part in 103 is achievable with this technique. [Copyright &y& Elsevier]

Sodium chromium oxide, NaCrO 2 , has received significant attention as positive electrode (cathode) for Na-ion batteries mainly due the high capacity retention of the material. In this paper, we use operando powder X-ray diffraction to investigate the structural evolution of O3–NaCrO 2 during Na-ion extraction and insertion with use of both liquid and solid-state electrolytes. This reveals a previously overlooked phase transition, causing formation of an unexplored O′3-Na x CrO 2 intermediate during Na-ion extraction (charge). The phase transitions within the electrode are investigated by sequential Rietveld refinement and distortion analysis, which shows that the discovered O′3-Na x CrO 2 intermediate accommodates the increasing interlayer repulsion and in-plane contraction with less distortion of the [NaO 6 ]-polyhedra as compared to the other observed phases. Our structural findings are corroborated by analysis of the Na-ion diffusion coefficients through the galvanostatic intermittent titration technique. Furthermore, the operando powder X-ray diffraction reveals substantial charge-discharge asymmetry with a significant preference for solid-solution and two-phase behavior during charge (Na-extraction) and discharge (Na-insertion), respectively. [Display omitted] • A new intermediate is observed during charge of NaCrO 2 cathodes. • Severe charge-discharge asymmetry is observed in the phase evolution for NaxCrO2. • The asymmetry appears to originate from differences in Na-diffusion coefficients. [ABSTRACT FROM AUTHOR]

Abstract: A discrete global grid system (DGGS) is a spatial data model that aids in global research by serving as a framework for environmental modeling, monitoring and sampling across the earth at multiple spatial scales. Topological and geometric criteria have been proposed to evaluate and compare DGGSs; two of which, intercell distance and the “cell wall midpoint” criterion, form the basis of this study. We propose evaluation metrics for these two criteria and present numerical results from these measures for several DGGSs. We also consider the impact of different design choices on these metrics, such as predominant tessellating shape, base modeling solid and partition density between recursive subdivisions. For the intercell distance metric, the Fuller–Gray DGGS performs best, while the Equal Angle DGGS performs substantially worse. For the cell wall midpoint metric, however, the Equal Angle DGGS has the lowest overall distortion with the Snyder and Fuller–Gray DGGSs also performing relatively well. Aggregation of triangles into hexagons has little impact on intercell distance measurements, although dual hexagon aggregation results in markedly different statistics and spatial patterns for the cell wall midpoint property. In all cases, partitions on the icosahedron outperform similar partitions on the octahedron. Partition density accounts for little variation. [Copyright &y& Elsevier]

Abstract: In comparison to state of the art fuel cell stack monitoring techniques, where for reliability and durability reasons either single cell or cell-block voltages are monitored separately, the new approach derives information about critical cell and stack status from the stack sum voltage only. The motivation for the development of such a technology is to establish a strongly simplified and low cost stack diagnosis unit. In comparison to the cell voltage monitoring (CVM) technology, where up to several hundreds voltage channels have to be measured separately or at least in pairs, the effort for wiring, contacting and instrumentation can be reduced dramatically. Critical cell operation occurs, if e.g. low air stoichiometry causes a sharp drop of voltage at a certain cell current. If in such case the current is superimposed by a small amplitude signal with specific frequency pattern, then the system response (i.e. stack voltage) will be distorted in the frequency domain. Particularly, this means that even if only one single cell is in a critical operation mode, it would cause distorted frequency fractions extractable from the entire stack voltage. Since this approach is related to the distortion of the frequency pattern only, noise and EMC issues are not significantly influencing the measuring quality. The instrumentation and processing effort is rather low and can be realized with a low cost DSP board. Measurement results for different critical stack operation modes, e.g. operation at low air or low hydrogen stoichiometry, with their correlation to the frequency distortion will be described and discussed. [Copyright &y& Elsevier]

SOI technology is now emerging as a mature technology applied in the analog IC design, which necessities an accurate model to describe distortion effects. In this paper a compact transistor model is proposed for distortion analysis of fully depleted SOI MOSFET operating in strong inversion regime. In the model, both short channel effects and self-heating effect (unique to SOI due to the buried oxide) are considered. To obtain a concise and accurate model, an approximation method is developed to determine the dominant physical effects in distortion analysis. The model agrees well with the experimental data. [Copyright &y& Elsevier]

• Introduction to a method measuring temperature dependent magnetic properties. • Post-determination of primary microstructure of 50CrMo4 after QT heat treatment. • Precise hardness estimation choosing the right measurement parameters. • Correlation between the effect of different precipitations and magnetic properties. • Categorisation of the effect of eddy-currents on the B-H hysteresis. This work investigates the effect of different initial microstructures on the electromagnetic magnetisation curves/hysteresis of 50CrMo4 steel and technically pure iron introducing a novel measurement method. Surprisingly little is known about the relationship between microstructure and the magnetic properties, although this is of great importance for a better understanding and multi-physics modelling of induction heat treatment. Analysis of the magnetic hysteresis and Distortion Analysis of Magnetic Excitation (DAME) are important techniques to characterise magnetic behaviour of materials. To perform these measurements, a specific measurement setup based on excitation circuit/yoke with secondary coils was implemented. Using these methods, the characterization of the effect of mechanical properties (i.e.: hardness) and different microstructures on electromagnetic magnetisation curves/hysteresis is possible with high precision. The effect of the eddy-currents on the B-H hysteresis shows a systematic behaviour, which opens the possibility for a new kind of categorisation of these effects. DAME shows a closely linear relationship with the assumed precipitation size allowing indirect analysis of the microstructure, also at elevated temperatures. [ABSTRACT FROM AUTHOR]

[Display omitted] • Reduction of hardware requirements for magnetic characterization. • Current controlled magnetization to amplify the distortion. • Algorithm to obtain a high SNR signal representative of the distortion. • Magnetic characterization of skin pass elongation (0.2–8.9%) of IF and DP steels. • Higher sensitivity to skin pass comparing with hysteresis loop and DAME profile. The distortion analysis of magnetic excitation (DAME) method has been recently proposed to facilitate magnetic measurements for non-destructive testing in which pick-up coils are not necessary. This method is based on the distortion effect that the permeability of the sample generates on the voltage across the excitation coil. The aims of the method presented in the present paper are to amplify this distortion effect using a current mode-controlled magnetization and to extract a distortion signal, of high signal-to-noise ratio (SNR), from the voltage measured in the excitation coil by means of a demodulation technique. This methodology is applied to different skin passed steels to characterize the elongation level, which is still a challenge for conventional non-destructive electromagnetic techniques. The relationships between the parameters derived from the distortion and from the hysteresis are studied. Measurements according to the DAME method are performed to verify the improvement in sensitivity for magnetic characterization. [ABSTRACT FROM AUTHOR]