The formation of metrology as government regulated activity in France

The article has discussed the historical process of development of metrological activity in France. It was revealed that the history of metrology is considered as an auxiliary historical and ethnographic discipline from a social and philosophical point of view as the evolution of scientific approaches to the definition of individual units of physical quantities and branches of metrology. However, in the scientific literature, the little attention is paid to the process of a development of a centralized institutional metrology system that is the organizational basis for ensuring the uniformity of measurements. It was shown that traditionally there are two periods of development of metrology based on the unification of weights and measures: the association under Charlemagne and the introduction of the decimal metric system during the French Revolution. Because this division has a mixed scientific and organizational basis, a new periodization of the development of French metrology from the position of state regulation was proposed. The highlighted stages include the primitive period and the first city-states, the time of the domination of the Roman Empire, the era of the coexistence of many measures, the chapters of Charlemagne, the feudal practices of the Middle Ages, the creation of royal standards under Henry II, the introduction and dissemination of the decimal metric system, the emergence of metrological institutes, laboratories, centers. At the State level the first step in organizing a centralized institutional metrology system was the creation of a testing laboratory, the second was the creation of National Metrological Bureau, national bodies for metrology, and the third was reorganization of the system and appointment of the National Testing Laboratory as the governing metrological body of France. Thus, the French metrology system has experienced many crises and upheavals in the process of its formation. However, France today is one of the most experienced and respected countries in the field of metrology, and at the international level, it was the one who laid the foundations for new metrological agreements, as well as the social, philosophical, scientific, political and geographical area of the new system of measures and weights.

Micro-Range Actuation by Pressure-Induced Elastic Deformation of 316L Steel Membranes Produced by Laser Powder Bed Fusion

In this paper, fundamental research is performed on membrane type actuators made out of 316L stainless steel, manufactured with Laser powder bed fusion (LPBF). A total of six membranes with membrane thicknesses ranging from 0.6 mm up to 1.2 mm were scanned using a high precision metrology system to measure the membrane for displacement at different actuating pressures. The membranes were furthermore investigated for roughness, porosity and thickness. This showed that the thinnest membranes skewed in the print direction when actuated. The remaining membranes achieved higher specific displacements than finite element simulations (FES) predicted, due to surface roughness and porosity. Membrane type actuators can be used for precise actuation within the micrometre range. LPBF allows the creation of internal pockets and membranes in a single metal piece. In opposition to the more commonly used polymers for membrane-type actuators, LPBF steel printed parts offer high stiffness and actuation force. However, due to limitations of the LPBF process on thin walls, large deviations from FES occur. In this paper, a CAD and FES compensation strategy is suggested, which makes future, more complex and effective, designs possible.

Improving the quality control of drinking water in Nicaragua through proficiency testing in a metrological multilateral cooperation project

The United Nations General Assembly explicitly recognized the human right to water and sanitation and acknowledged that drinking water is essential to the realization of all human rights in a 2010 resolution. Supporting and strengthening the quality infrastructure in countries throughout the world guarantees more reliable water quality analyses, thus reducing the risks to consumers’ health. The present paper describes a multilateral cooperation project developed in Nicaragua to improve the country's quality infrastructure and, in turn, the quality control of drinking water. The project was developed with the support of National Metrology Institutes (NMIs) from the Inter-American Metrology System (SIM), the Physikalisch Technische Bundesanstalt (PTB) and the participation of research institutes and laboratories in Nicaragua. Several mechanisms such as awareness seminars, workshops, metrological screenings, peer review of the laboratories’ quality systems, and organizing proficiency testing (PT) were used to successfully achieve the cooperation goal. As a result, technical infrastructure for the organization of PT rounds in Nicaragua was implemented to evaluate the relevant physicochemical parameters such as pH, chloride (Cl−), and nitrate (NO3−) in drinking water. The results from the PT rounds which took place during the two-year cooperation project showed substantial improvement in the performances of the participating laboratories, and therefore, in their measurement methods. Finally, this article shows how multilateral cooperation projects can strengthen the quality infrastructure, improving and ensuring the quality control of drinking water.

Distortion measurements of sound pressure level generated by a pistonphone

A supplementary interlaboratory comparison on pistonphone calibration was performed between 2018 and 2020 under the auspices of the Inter-American Metrology System. Seven national metrology institutes took part in this comparison. One pistonphone was circulated among the participants for measurement of the generated sound pressure level, frequency, total distortion + noise and total harmonic distortion. This paper presents the results of distortion measurements and analyzes them. From the stability check, notable variances with respect to reported measurement uncertainty were observed. From reported results, a large difference between the estimated uncertainties by the participants was noted. Convergence between results was found when measurements were performed using one-inch microphone while some divergence between results was found when measurements were performed using half-inch microphone. In addition, these results (using one-inch and half-inch microphones), even when obtained by the same institute, sometimes were different. Reasons for these findings are discussed and suggestions for future comparisons are presented.

Satellite architecture and preliminary in-orbit experiment of Taiji-1

Taiji-1 is China’s first in-orbit technology validating satellite related to spaceborne gravitational wave (GW) detection. The satellite was launched at 600km sun synchronized orbit on 31 August 2019. It has accomplished its mission goals while all subsystems have validated their key technologies in orbit. The subsystems include optical metrology system (OMS), drag-free attitude control system (DFACS), thermal control subsystem, high-quality microgravity satellite platform and so on. This paper presents system architecture of Taiji-1 analyzing in-orbit experimental results of thermal stability, reaction wheel vibration contributing to the noise of gravitational reference sensor (GRS) measurement noise, and the center-of-mass (CoM) of GRS calibration.

The drag-free control design and in-orbit experimental results of “Taiji-1”

Taiji is China’s spaceborne gravitational wave (GW) detecting project, which is designed to detect GW sources ranging from 0.1mHz to 1Hz. Taiji-1, launched on 31 August 2019, is a pilot study mission to prepare necessary technology for Taiji pathfinder. Two major technology units were tested on Taiji-1: Optical Metrology System and Drag-free Control System (DFCS). In this paper, we try to illustrate the design of DFCS; the implementation strategy of experiment and the first results of in-orbit experiment. The disturbance reduction capability of Taiji-1’s DFCS is demonstrated by the in-orbit experimental performance analysis.