Zusammenfassung Ansprechzeiten von Thermometern für die thermische Energiemessung müssen im Rahmen einer Baumusterprüfung in Wasser mit einer Strömungsgeschwindigkeit von v = 0,3 m s −1 bestimmt werden. Thermometerhersteller verwenden die Messung der Ansprechzeit darüber hinaus zur Qualitätskontrolle bei der laufenden Fertigung von Thermometern. Bei ihnen existieren unterschiedliche Prüfeinrichtungen zur Bestimmung des dynamischen Verhaltens. An den Versuchseinrichtungen der TU Ilmenau kann die Ansprechzeit von Thermometern unter sehr kontrollierten Bedingungen reproduzierbar bestimmt werden. Zwischen den Herstellern und der TU Ilmenau fanden daher bilaterale Vergleichsmessungen statt. Diese zeigten eine sehr gute Übereinstimmung der ermittelten Werte, trotz unterschiedlicher Randbedingungen in den jeweiligen Laboren. Mit einem nahezu baugleichen Thermometer eines dritten Herstellers wurden daher systematisch der Einfluss der Eintauch- und der Anströmgeschwindigkeit auf die Ansprechzeit an der Prüfeinrichtung der TU Ilmenau untersucht und eine Messunsicherheitsbilanz erstellt. Die Ergebnisse legen nahe, dass eine genaue Kenntnis der Strömungsverhältnisse im Wasserbad eine untergeordnete Rolle spielt, solange die Strömungsgeschwindigkeit groß genug ist und ein hinreichend großer Wärmeübergangskoeffizient erreicht wird.

Abstract Breast cancer is one of the most common cancers in women worldwide. Determination of the tumor margins is essential for complete resection of the tumors while preserving healthy tissue. To improve the differentiation between healthy and malignant tissue, a hyperspectral measurement setup with a broad spectral range was developed to detect characteristic spectral differences by measuring ex vivo surgical specimens. The results described here, are obtained from an ex vivo study including 19 patients, in which for each patient one tissue sample from the tumor and one healthy site are examined. The obtained spectra show promising spectral differences, which allowed the tissue to be differentiated from a test group of four patients not involved in the training with a classification accuracy of approximately 85 % using only spectral information without taking into account the spatial structure of the tissue. Comparable results of approximately 80 % and 86 % were also achieved with an evaluation reduced to four and six spectral channels, respectively. It was thus demonstrated that tumor and normal tissue can be differentiated with few spectral channels in the visible to near-infrared spectral range, enabling the development of a real-time capable multispectral measurement system for intraoperative use.

Zusammenfassung Im Rahmen der hier vorgestellten Arbeiten wurde eine prozessfähige Probennahme mit integrierter Gaschromatografie entwickelt, mit der eine Echtzeitüberwachung von Verunreinigung im Stoffstrom bei der Verarbeitung von Kunststoffrezyklat ermöglicht werden soll. Dazu wird ausgenutzt, dass im bestehenden Prozess über der Kunststoffschmelze ein abgeschlossener Gasraum vorhanden ist, der fortlaufend evakuiert wird. Die Herausforderungen liegen in der Identifikation der dort vorkommenden Stoffe und in der Entwicklung einer geeigneten Probennahmetechnik, die eine repräsentativ zusammengesetzte Probe in die Gaschromatografie überführt. Die für eine echtzeitfähige Überwachung notwendigen schnellen Temperaturwechsel konnten in einem Demonstrator so realisiert werden, dass mehr als zwölf Messungen pro Stunde möglich sind. Damit kann im Gegensatz zu gängigen Offline-Laborverfahren eine zielgenaue Identifikation kontaminierter Stoffabschnitte realisiert werden.

Zusammenfassung Um beim Drehen die Standzeit von Werkzeugen und die Produktqualität zu optimieren, wird ein optoelektronisches Sensorsystems für in situ Werkzeugverschleißmessungen an einer Drehmaschine realisiert. Das Sensorsystem besteht aus einem chromatisch-konfokalen Sensor, präzisen Linearachsen und einem Roboterarm. Um trotz einer Roboterpositionierunsicherheit von 50 μm die geforderten Wiederholgenauigkeiten zu erreichen, wird ein Werkzeugkoordinatensystem (WKS) basierend auf den unverschlissenen Kantenbereichen des Werkzeugs eingeführt. Im Experiment mit einer optisch kooperativen Referenzkugel wird eine Repositionierunsicherheit von 6 μm nachgewiesen, d.h. die Positionierunsicherheit konnte um fast eine Größenordnung reduziert werden. Darüber hinaus zeigen erste Messungen von Geometrie und Verschleiß an verschiedenen Werkzeugen eine gute Übereinstimmung mit Referenzmessungen und belegen die Eignung des Sensorsystems für Werkzeugverschleißmessungen.

Abstract We present a highly accurate measurement setup and related methods for the efficient characterization of inductive rotary position sensors. The test bench is designed to measure analog sine/cosine output signals of the device under test (DUT) under nominal conditions as well as deliberate misalignment, such as offset and tilt tolerances- enabling analysis of DUT performance w.r.t. the angle deviation, the harmonic decomposition, and tolerance sensitivities. The uncertainty of measurements with the proposed test bench setup is quantified with a repeatability study and an effort is made to determine the systematic deviation. By means of laser-guided positioning, the printed circuit board (PCB) of the DUT is automatically positioned relative to the rotary axis (runout ±5 μm) in airgap and radial direction (repeatability 5 μm, total deviation 30 μm). The setup is capable of high-speed measurements at a rotation speed of at least 2000 min−1. The proposed measurement setup is flexible to accommodate a wide range of rotary position sensors and enables fast (less than 3 s per tolerance scenario) and automated characterization of the DUT angle deviation with excellent accuracy better than 10′′ (0.003∘).

Abstract The paper highlights the global dimension of the energy transition and the crucial role of quality infrastructure. With a growing global population and rising energy consumption, the demand for electricity worldwide could almost double by 2050. This requires a fundamental shift from fossil energy systems to more sustainable and environmentally friendly alternatives. The energy transition involves not only technological but also societal transformations that enable the shift to renewable energy sources. A key facilitating and driving factor is quality infrastructure: it encompasses metrology, standardization, accreditation, conformity assessment, and market surveillance, enhancing the quality, safety, and environmental compatibility of products, services, and processes. The projects of the Physikalisch-Technische Bundesanstalt (PTB) International Cooperation contribute significantly to the development of a robust and reliable quality infrastructure that promotes international trust in products and services. Through close cooperation with global partners, internationally recognized cross-sector standards and good measurement and testing practices, for example, are developed to sustain free and fair trade while boosting safety and quality. This collaboration enables partner countries to establish their own national quality infrastructure, thus strengthening their position in global value chains and advancing the global energy transition. These complex interrelations are illustrated by examples from Vietnam and Tunisia.

Abstract Hydrogen is an energy gas that is used commercially in a variety of applications that include fuel cells. Before utilization, hydrogen must meet certain quality characteristics. ISO 14687 specifies the limit values of impurities in H2. Carbon monoxide is an impurity that must be accurately measured in commercial H2 and its limit value as specified in ISO 14687 is 200 nmol/mol. In this work, we present a new laser spectrometric method for traceable CO impurity measurements in H2. The method is based on Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS). We demonstrate the applicability of the method by measuring CO amount fractions in H2 in the range of 0.05–20 μmol/mol. The traceability of the results to the SI units is addressed and uncertainties are evaluated following the GUM (Guide to the expression of uncertainty in measurement) principles. For the CO amount fraction measurement range of 0.05–20 μmol/mol, the relative combined uncertainty of the results is in the 1.5 % range, k = 1.

Abstract This work presents a study regarding the expected value of the root mean square value of the residuals obtained by fitting a three-parameter sinusoidal model to a set of data points. The influence of phase noise on the signal or jitter in the sampling instants is derived from a theoretical point of view. A detailed presentation is given justifying the analytical expression proposed. Approximations are made in order to obtain a simple mathematical expression that relates the factors that play a role, namely the phase noise or jitter standard deviation, the number of data points and the sinusoidal signal amplitude. Numerical simulation results, obtained with a Monte Carlo type procedure, are presented which validate the approximations made and show the accuracy of the analytical expression for a range of parameter values. The phase noise or jitter that affected the data points was considered to be normally distributed with a null mean.

Abstract In the context of future cities and smart campuses, sustainability is a key challenge for future developments. The Smart Metrology Campus (SMC) data infrastructure, implemented as a lambda architecture, supports the collection of both sensor data and metrological metadata for electric energy meters. A Digital Twin for energy-aware High-Performance Computing can use the data to optimize the energy usage. This paper presents two possible integrations of the SMC data with the Digital Twin: using the collector agent of the Digital Twin and the serving layer of the SMC data infrastructure, and a direct integration of the speed layer into the Digital Twin database. Both methods are evaluated based on data access latency, historic data availability, and system complexity. The integration of the SMC lambda architecture with the Digital Twin offers benefits in terms of reduced maintenance, improved data flow stability, and easier extension for additional sensors or metadata.

Abstract Assessing the degradation of electrical contact surfaces using three-dimensional (3D) measurements is often costly and complex, limiting their use in real-time monitoring. To address this, a two-dimensional (2D) image-based approach is proposed as an efficient and practical alternative. The method uses 2D texture features, such as Gray-Level Co-occurrence Matrix (GLCM) and Local Binary Patterns (LBP), to quantify surface degradation. A novel Image-Based Degradation Index (IDI) is introduced, and its relationship with degradation extent is modeled using a Random Forest (RF) algorithm optimized by Particle Swarm Optimization (PSO). Validation against 3D data confirms the accuracy of 2D predictions. The results show that 2D imaging provides a reliable and cost-effective solution for assessing contact health, with strong agreement between 2D predictions and 3D measurements.