Effective from 20 May 2019, the kilogram is now defined in terms of the numerical value of the Planck constant h. Replacing the artefact definition of the kilogram by a new one based on the mass of a particle, or the atomic mass constant m_u, would have been preferable for ease of understanding, among other reasons. In this paper we will discuss some educational limitations of teaching to different audiences the new definition and corresponding realizations of the kilogram.

The selective catalytic reduction, an after-treatment method using diesel exhaust fluid (AdBlue), is needed to reduce the emissions of diesel combustion processes. It is crucial to monitor the diesel exhaust fluid. This article presents a platinum thin-film sensor using the 3-omega method to characterize the diesel exhaust fluid. The information about the concentration of urea in water can be extracted. The results show that this sensor can determine the urea content to within 1 % by weight.

The dose rate and spectral distribution of X-ray emissions from laser materials processing have been determined using a thermoluminescence detector (TLD)-based spectrometer. The penetration depth of the radiation into the spectrometer depends on its energy, so that the energy-resolved spectrum of the radiation can be calculated from the TLD dose values by means of mathematical methods (Bayesian deconvolution). The measurements are traceable to the SI.

The estimation of the six-degree-of-freedom position and orientation of an end effector is of high interest in industrial robotics. High precision and data rates are important requirements when choosing an adequate measurement system. In this work, a six-degree-of-freedom pose estimation setup based on laser multilateration is described together with the measurement principle and self-calibration strategies used in this setup. In an experimental setup, data rates of 200 Hz are achieved.

For safety, environmental and economic reasons, methane leak detection is one of the most requested tasks for gas measurement devices. This paper compares the performance of a laser-based optical and acoustical detection scheme at different wavelengths and laser types, respectively. This forms a good basis for further developments of methane leak detection devices or can help to choose the right configuration for a certain methane leak detection application.

Differential thermal analysis (DTA) was used to examine the effect of the particle size and morphology of Co₃O₄ on its thermal response under exposure to 1 % CH₄. The DTA response results from the catalytic oxidation of methane. Co₃O₄ samples differing in particle size and morphology were produced by ball milling or were synthesized. The investigations performed with temperatures between 250 and 450 °C reveal that both particle size and shape have a considerable effect on thermal response.

This paper deals with the electrical investigation of various sand mixtures used in foundries for mold and core production. It is possible to classify various molding sand mixtures reproducibly on the basis of their electrical characteristics. This knowledge can now be used to develop measurement systems for processes in the foundry industry and thus increase product quality. In addition, resources can be conserved, and functioning closed-loop systems can be integrated into foundry processes.

NiCr-carbon thin-film strain gauges offer the outstanding characteristic of a very high strain sensitivity. This can be very advantageous for many high-precision mechanical sensors like load cells. A downside of sensors based on these NiCr-carbon strain gauges is a rather large creep error, meaning reversible signal deviations at a constant load. We present two applicable methods for adjustment of the creep error: a modification of the film composition and a modification of the strain transfer.

A novel, low-cost measurement device for simultaneous high temperature measurements of the electrical conductivity and Hall coefficient has been developed. Simulations were used to design a suitable screen-printed planar platinum heating structure that generates temperatures of up to 600 °C. Simulations of the temperature distribution have been validated using thermal imaging. Measurements were compared with data from the literature to validate the functionality of the novel device.

Ion-selective electrodes have been proven useful in water analysis. They are usually used as single-rod measuring chains in different designs, which are manufactured using precision mechanical manufacturing and assembling technologies. The paper describes a microsystem technology approach for the fabrication of miniaturized electrochemical sensors. Design, manufacture, and performance of the novel ceramic multilayer-based sensor array are presented in the paper using various examples.

Virtual assembly (VA) is a method for the quality prediction of assemblies considering local form deviations of relevant geometries. Point clouds of measured objects are registered in order to recreate the objects’ hypothetical physical assembly state, which is strongly influenced by the measurement uncertainty of individual points. Thus, we studied the propagation of uncertainties by VA. The results reveal larger propagated uncertainties by VA compared to the unconstrained Gaussian best fit.

The Physikalisch-Technische Bundesanstalt has set up a primary method for the calibration of the spectral responsivity of thermal detectors in the near- and mid-infrared spectral range. This method uses the calculable radiation of a blackbody radiator and optical bandpass filters. The obtained results with relative standard measurement uncertainties between 5 % and 19 % are consistent with previous calibrations at PTB's national primary detector standard and extend the usable wavelength range.

The actuators of precise positioning based on LiNbO₃ or LiTaO₃ bimorph structures are considered. They consist of two joined plates: one of them lengthens and the other one shortens under the influence of an electric field and, as a result, the actuator bends. Such a device ensures small movements of probes in scanning probe microscopes, micro-electromechanical systems, micro-motors, etc. We determine the optimal orientations of the plates, ensuring the highest possible actuator displacements.

We have prepared an article that demonstrates one of the ways to recognize objects on the ground surface. This paper is a result of experimental data that were collected with unnamed aerial vehicles (UAVs) with synthetic aperture radar. Although UAV radar has a small monitoring area, we noted that such pictures can contain the steady features of the mutual arrangement between detected objects. We have constructed an artificial neural network that solves the tasks of group object recognition.

A TIR100-2 emissometer is used to measure the emissivity of thermal insulation products using the low-emissivity effect to increase the thermal resistance, but the uncertainties of measurements on low-emissivity foils were not known. The study allowed the determination of the uncertainty through the detailed analysis of the measurement principle and the determination of the influences of the parameters. The measurement results were validated by comparison to a reference measurement setup.