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Measurement systems operating in cold climate regions are directly affected by harsh atmospheric conditions. Under severe conditions, e.g. ice accretion on a sensor surface can lead to a degraded performance or even a breakdown of the measurement system. In order to avoid such critical conditions, measures to prevent even partial icing of the sensor system have to be applied. E.g. weather and radiation shields are equipped with heating elements to maintain ice free conditions of a critical sensor surface. However, the control of the heating functionality is often based on little knowledge about the actual conditions on the surface. This leads to unnecessarily high power consumption of the heating module in case of a pessimistic control strategy. Hence a further sensing modality is of interest, which lowers the uncertainty in the icing prediction, eventually leading to a minimum of heating periods. In this work we present a general concept of a combined sensor and thermal actuator structure, which allows for a reliable detection and prevention of critical icing conditions on surfaces. The concept exploits a shared front-end structure for both sensing and heating to achieve space constraints comparable to traditional shields. We discuss the design of the front-end topology and the different modes of operation of the sensor and actuator system. The functionality of the approach is experimentally investigated by means of laboratory tests. [ABSTRACT FROM AUTHOR]

Pneumatic conveying is a widely applied technique for the transportation of powders. Dense phase conveying such as slug flow is the preferable operating condition of such transport systems. Advantages are the reduced energy and conveying gas consumption and reduced material wear. The design and the operation of dense phase conveyors is a challenging task due to complex flow dynamics and the lack of reliable flow meters, which are crucial for process control. In this work the capabilities of electrical capacitance tomography (ECT) for slug flow parameter estimation are analysed. The estimation of flow parameters is addressed and demonstrated by means of laboratory experiments. Amongst other parameters it is shown that mass concentration distributions as well as particle velocity fields can be obtained from tomographic image reconstruction results, which are substantial parameters for potential mass flow metering. Additionally, the proposed estimation techniques are applied to signals provided by an ECT system, which is installed within a large-scale pneumatic conveyor of an industrial process plant. It is observed that also Geldart group A powders with Archimedes numbers in the scale of A r ≈ 1 e 0 are conveyable in slug-like structures which can be separated by stationary or non-stationary layers. Furthermore, various slug flow properties of powders with A r > 1 e 2 reported in literature are confirmed but also deviating properties are observed, leading to novel insights into horizontal dense phase flow processes of powders with A r ≈ 1 e 0. The results demonstrated in this work are pointing out the capabilities of ECT for flow analyses, which are enabling further insights into flow mechanisms and future developments of flow meters for dense phase flow processes. [Display omitted] • Electrical capacitance tomography-based slug flow parameter estimation. • Tomographic imaging of mass concentration distributions. • Differentiation between slug velocity and particle velocity. • Application within an industrial-scale pneumatic conveyor with a length of 2 km. • Novel insights into dense phase conveying of Geldart group A powders with A r ≈ 1 e 0. [ABSTRACT FROM AUTHOR]

Measuring the state of batteries and their change over time is essential during research and development. A number of standard test methods are available to determine specific cell parameters, such as capacitance, internal resistance, coulombic efficiency, etc. Although these methods have been in use for a long time, a thorough analysis of the uncertainties associated with them – especially when using high-precision measuring equipment – is still lacking. Therefore, a primary goal of this work is to close this gap. For each method, the results of the uncertainty analysis are divided into a variable part (noise, jitter) and a constant part (absolute accuracy). In addition, the theoretical analysis is accompanied by practical measurement results from a high-precision measurement hardware, demonstrating what is currently possible with state-of-the-art equipment. The constant part of the uncertainty is mainly limited by the used calibration equipment. For the variable part of uncertainty, the situation is somewhat more varied. Using a battery temperature control with a variability of only ± 0. 1 ∘ C , capacity, capacity change and coulombic efficiency still show a strong influence on the prevailing small temperature variations. For the voltage analysis methods (differential capacity and voltage analysis) the predominate factor is voltage noise and drift. • Ratiometric quantities, e.g. Δ C or CE, reach uncertainties in the low ppm range. • Non-ratiometric quantities, e.g. capacitance, are much worse at several 100 ppm. • The value-to-value jitter is very low, ranging from a few to a few tens of ppm. • For low uncertainty, a highly stable temperature control (few mK) is necessary. [ABSTRACT FROM AUTHOR]