Metrology, Volume 3, Issue 3 (September 2023) – 6 articles

This article provides a report of the recent workshop on “The metrology of quantities which can be counted” organised jointly by the International Committee for Weights and Measures’ Consultative Committees for Amount of Substance (CCQM) and for Units (CCU). The workshop aimed to trigger a discussion on counting and number quantities across the metrological community so that a common understanding of counting and a common nomenclature could be achieved and there was clarity on the differences between these increasingly important concepts. This article details the background to the workshop, provides a summary of the presentations given and the discussions on the topics raised. It also reports the conclusions, agreed actions and next steps resulting from the workshop. Full article

Time and frequency are quantities that have seen a proliferation and diffusion of tools, unimaginable until a few decades ago, and whose application implications are multiplying in a digital society, now characterized by an absolute lack of temporal and spatial limits. Today’s world requires a perfect synchronism of human activities, both for the need to identify with certainty the moment of commercial transactions and to accurately describe biological phenomenologies, which affect the social life of individuals to the point of having repercussions on issues such as safety, production and manufacturing organization. In this regard, the recent award of the Nobel Prize for Medicine for the discovery of the gene capable of controlling our internal biological clock is significant. This paper describes the social implications connected to time measurements, analyzing some very original application effects, ranging from the typical cadences of production activities to sports applications, going so far as to highlight its apparent anomaly of adopting, unlike all other physical quantities, duodecimal and/or sexagesimal scales. Real time and perceived time can both converge and diverge, and this is almost never objectifiable, as it varies from individual to individual, according to individual experiences or sensitivities. This paper is a point of reflection attempting to understand how the chronology of major historical events influenced the organization of time as it is known today and how we arrived at actual measuring instruments so accurate and interconnected with the social sphere. The evolution of calendars and instruments for measuring relative time is described in terms of their specificity. Full article

The rate of automation in European industry is increasing continuously. In production metrology, the trend is shifting from measurement laboratories towards integration of metrology into the production process. Increasing levels of automation and the current skills shortage are driving demand for autonomous production systems. In this project, a roughness measurement system was developed that is fully integrated into machine tools and enables fully automatic roughness measurement of part surfaces during the machining process. Using a skidless measurement system, it was possible to obtained measured roughness values comparable to those obtained in measuring rooms under optimal conditions. The present paper shows the development process of the prototype and provides an overview of different application scenarios for in situ measurement of machine tools. In situ roughness measurement has high potential in the future of metrology in industrial applications. Not only can surfaces be measured directly in the process, sub-processes can be triggered based on the measured values, allowing the production process to react flexibly to actual conditions. Potential improvements in metrology and significant optimizations of the entire production chain are highlighted in this paper. Full article

Engine noise, as a source of sound pollution for humans and the environment, can be reduced by designing a high-performance muffler. This study presents a novel, organized design process of that muffler for the KTM390 engine as a case study. The acoustic simulation analysis is performed in COMSOL software and aerodynamic analysis is performed in ANSYS Fluent. The features of the muffler considered in this designing process are the overall length of the muffler, the presence of baffles and related parameters (baffle distance, baffle hole diameter, and baffle hole offset), and the effects of extended tubes. In order to evaluate the acoustic performance of the muffler, an objective function has been defined and measured on two frequency ranges, 75–300 Hz and 300–1500 Hz. For evaluating the aerodynamic performance of that, the amount of backpressure is analyzed to achieve a maximum of 3.3 kilopascals for this muffler. The selection of the appropriate parameters includes comparing the resulting transmission loss curves and quantitative evaluation of objective functions (for transmission loss) and backpressure. This organized design process (i.e., tree diagram) leads to an increase in the efficiency of designing mufflers (for example, 41.2% improvement on backpressure). Full article

In this paper, the development of a fission-gas collecting and physical-analysis-enabling instrument was proposed for small-volume determination. Analysis specifications require a design capable of accurately and repeatably determining volumes in the range of 0.07–2.5 mL. This system relies on a series of gas expansions originating from a cylinder with known internal volume. The combined gas law is used to derive the unknown volumes from these expansions. Initial system designs included one of two known volumes, 11.85 ± 0.34 mL and 5.807 ± 0.078 mL, with a manifold volume of 32 mL. Results obtained from modeling this system’s operation showed that 0.07 mL can be determined with a relative expanded uncertainty greater than 300% (k = 2) for a single replicate, which was unacceptable for the proposed experimental design. Initial modeling showed that the volume connecting the known volume and rodlet, i.e., the manifold volume, and the sensitivity of the pressure sensor were key contributors to the expanded uncertainty of the measured rodlet volume. The system’s design limited the available options for pressure sensors, so emphasis was placed on the design of the manifold volume. The final system design reduced the manifold volume to 17 mL. These changes in design, combined with replicate analysis, were able to reduce the relative expanded uncertainty by ±12% (k = 2) for the 0.07 mL volume. Full article