Istituto Nazionale di Ricerca Metrologica
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On-Site Calibration Procedure and Uncertainty Contributions on Air Temperature Sensors
No full textDue to the increasing demand of climate change studies, traceability of measurements according to the International System of Units (SI) becomes fundamental to establish data quality and comparability in time. With the aim of guaranteeing the traceability, in October 2022, an on-site calibration of three thermometers operated by the Osservatorio meteorologico di Moncalieri was assessed. The calibration by comparison against traceable travelling standards was performed in a transportable thermal chamber manufactured by the Istituto Nazionale di Ricerca Metrologica (INRIM). Results showed that the main uncertainty contributions to the expanded uncertainty were the interpolation method, the chamber inhomogeneity and the repeatability of the sensors under calibration. This current calibration was compared with previous calibration in 2012 (on-site calibration) and in 2016 (laboratory calibration). The comparison analysis evidenced the drift effect on the thermometers and the importance of having an active calibration program to reduce this effect. Regarding the expanded uncertainty, both on-site calibrations presented the same order of magnitude and smaller than the correction values. This paper points out the advantage of performing an on-site calibration: since the calibration involves the same dataloggers and cables in the same environmental conditions, the calculated calibration curve represents more convincingly the real measurement conditions
Comparison in humidity (dew-point temperature high range) dew point temperature +30 °C to 95 °C
No full textThe report summarises the results of the EURAMET.T-K8 key comparison (EURAMET Project No. P 717) in the field of humidity. The comparison covers the dew-point temperature range from +30 °C up to + 95 °C dew point temperature. The report gives details of the scheme, procedure and analysis of the comparison. The overall results display a very good agreement of the 16 participating laboratories. The two dew-point hygrometers used as travelling standard were sufficiently stable. The linkage to the corresponding CCT-K8 comparison will be calculated when the final results for both comparisons are available. Possible procedures are described in the text. In the conclusion, some remarks for improvement for future RMO key comparisons are given.
To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.
The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA)
The thermodynamics of self-assembled monolayer formation: a computational and experimental study of thiols on a flat gold surface
No full textA methodology based on molecular dynamics simulations is presented to determine the chemical potential of thiol self-assembled monolayers on a gold surface. The thiol de-solvation and then the monolayer formation are described by thermodynamic integration with a gradual decoupling of one molecule from the environment, with the necessary corrections to account for standard state changes. The procedure is applied both to physisorbed undissociated thiol molecules and to chemisorbed dissociated thiyl radicals, considering in the latter case the possible chemical potential of the produced hydrogen. We considered monolayers formed by either 7-mercapto-4-methylcoumarin (MMC) or 3-mercapto-propanoic acid (MPA) on a flat gold surface: the free energy profiles with respect to the monolayer density are consistent with a transition from a very stable lying-down phase at low densities to a standing-up phase at higher densities, as expected. The maximum densities of thermodynamically stable monolayers are compared to experimental measures performed with reference-free grazing-incidence X-ray fluorescence (RF-GIXRF) on the same systems, finding a better agreement in the case of chemisorbed thiyl radicals.Investigation of the formation process of self-assembled monolayers by computationally estimating the chemical potential of thiyl and thiol monolayers on gold
Sistema per il monitoraggio strutturale di strutture e corrispondente procedimento per il monitoraggio strutturale di strutture
No full textHydrogen blending effect on fiscal and metrological instrumentation: A review
No full textA green hydrogen (H2) economy requires a sustainable, efficient, safe, and widespread infrastructure for transporting and distributing H2 from production to consumption sites. Transporting a hydrogen/natural gas (H2NG) mixture, including pure H2, through the existing European natural gas (NG) infrastructure is considered a cost-effective solution, particularly in the transitional phase. Several reasons justify the H2NG blending option. The NG infrastructure can be efficiently repurposed to transport H2, by blending H2 with NG, to operate as H2 daily storage, matching production and demand and to enable large-scale seasonal H2 storage. Although many benefits exist, the potential of existing NG grids for transporting and distributing green H2 may face limitations due to technical, economic, or normative concerns. This paper focuses on the state of the art of the European NG transmission and distribution metrology normative framework and identifies the gaps to be filled in case of H2NG flowing into the existing grids. The paper was revised to provide a comprehensive analysis of the practical implications resulting from the H2NG blend option
Electric field measurements in preclinical MRI at 11.7 T and 7 T for experimental SAR comparison
No full textSAR assessment is a major concern in MRI. The energy absorbed by tissues increases quadratically with the static magnetic field; therefore, ultra-high field (>= 7 T) systems require careful dosimetry to exploit their potential. The objectives are to validate the use of electric-field probe for SAR assessment for high-field MRI, and to study the advantages and drawbacks of E-field measurements. The experiments were performed at 7 and 11.7 T on preclinical systems in a phantom with calibrated dielectric properties. Absolute values of the E-field were measured according to position inside a birdcage coil and electrical conductivity, local temperature increase were simultaneously evaluated with operating RF frequency, as well as the re-positioning precision through five repetitive measurements. Results yielded a 14.8 +/- 0.36 W/kg SAR near the coil's capacitors compared to 6.8 +/- 0.17 W/kg estimated at the center of the coil. The temperature rise was nevertheless higher in the center likely due to heat transfer effects. The SAR measured in similar conditions was 5.2 times higher at 11.7 T than at 7 T. The probes induced no visible artefact, and the test to estimate the reproducibility of positioning the sensors granted a low 2.3 % coefficient of variation. Measuring both the cause (E-field) and the effect (temperature rise) yielded different information, both useful in the context of EM simulation validation
Report on EURAMET supplementary comparison on measurement of a 1 mm stage micrometer
Full text linkThe metrological equivalence of national measurement standards and of calibration certificates issued by national metrology institutes is established by a set of key and supplementary comparisons chosen and organized by the Consultative Committees of the CIPM or by the regional metrology organizations in collaboration with the Consultative Committees.
At its meeting in Espoo, 16-17 October 2017, the EURAMET Technical Committee for Length (TC-L) decided to carry out a supplementary comparison on stage micrometer measurements, named EURAMET.L-S29, with BEV (Bundesamt für Eich- und Vermessungswesen) as the pilot laboratory. The results of this international comparison will support the Calibration and Measurement Capabilities (CMCs) declared by the NMIs in the CIPM Mutual Recognition Arrangement (MRA). The comparison was registered in November 2019 at EURAMET and January 2020 at KCDB. Artefact circulation started in August 2020 and was completed in September 2022
Responsiveness and Precision of Digital IMUs under Linear and Curvilinear Motion Conditions for Local Navigation and Positioning in Advanced Smart Mobility
Full text linkSensors based on MEMS technology, in particular Inertial Measurement Units (IMUs), when installed on vehicles, provide a real-time full estimation of vehicles' state vector (e.g., position, velocity, yaw angle, angular rate, acceleration), which is required for the planning and control of cars' trajectories, as well as managing the in-car local navigation and positioning tasks. Moreover, data provided by the IMUs, integrated with the data of multiple inputs from other sensing systems (such as Lidar, cameras, and GPS) within the vehicle, and with the surrounding information exchanged in real time (vehicle to vehicle, vehicle to infrastructure, or vehicle to other entities), can be exploited to actualize the full implementation of "smart mobility" on a large scale. On the other hand, "smart mobility" (which is expected to improve road safety, reduce traffic congestion and environmental burden, and enhance the sustainability of mobility as a whole), to be safe and functional on a large scale, should be supported by highly accurate and trustworthy technologies based on precise and reliable sensors and systems. It is known that the accuracy and precision of data supplied by appropriately in-lab-calibrated IMUs (with respect to the primary or secondary standard in order to provide traceability to the International System of Units) allow guaranteeing high quality, reliable information managed by processing systems, since they are reproducible, repeatable, and traceable. In this work, the effective responsiveness and the related precision of digital IMUs, under sinusoidal linear and curvilinear motion conditions at 5 Hz, 10 Hz, and 20 Hz, are investigated on the basis of metrological approaches in laboratory standard conditions only. As a first step, in-lab calibrations allow one to reduce the variables of uncontrolled boundary conditions (e.g., occurring in vehicles in on-site tests) in order to identify the IMUs' sensitivity in a stable and reproducible environment. For this purpose, a new calibration system, based on an oscillating rotating table was developed to reproduce the dynamic conditions of use in the field, and the results are compared with calibration data obtained on linear calibration benches
Ultrasonic cavitation under microwave irradiation: bubbles and acoustic emissions
Full text linkUltrasound (US) irradiation and microwave (MW) heating of aqueous solutions have shown synergetic effects and can foster advanced processing when applied simultaneously or sequentially [1]. Here we try to characterize in more detail the acoustic cavitation phenomena taking place in such setups. Our aims comprise a better understanding of the physical effects, but also a suitable way to monitor cavitation activity of the system. To this end, we conduct several types of experiments where acoustic emissions of sonicated and heated water are recorded and analyzed. Partly the bubbles are observed in parallel with high-speed imaging (see Fig. 1). Results show that essentially two different states of cavitation can appear, depending on state and history of the system parameters: (i) a "gassy" cavitation state where large and weakly collapsing bubbles occur with acoustic emissions remaining on a lower level; and (ii) a "hard" cavitation regime with smaller and stronger collapsing bubbles where acoustic emissions are on a high level. The regimes are similar to the non-degassed and degassed state of cavitating liquid that are encountered, for instance, during pre-treatment of water by heating and ultrasonic degassing in the context of cleaning applications [2]. Here, however, the microwave heating plays a special role that is not yet fully understood. In particular, turning MW on and off during sonication can alternately switch between gassy (MW on) and hard (MW off) cavitation regimes, even without significant temperature (i.e. air saturation) changes of the liquid. Our results indicate (a) that acoustic cavitation emissions into air can be used for cavitation assessment, (b) that simultaneous application of US/MW can compromise sonochemical activity by switching to a soft, gassy cavitation regime, (iii) that alternating or pulsed US/MW application might be a favorable strategy for improvement of synergy of both energy sources, and (iv) that the microscopic degassing and nucleating effects of MW in connection with US still need more exploration
Artificial fingerprints engraved through block-copolymers as nanoscale physical unclonable functions for authentication and identification
Full text linkBesides causing financial losses and damage to the brand's reputation, counterfeiting can threaten the health system and global security. In this context, physical unclonable functions (PUFs) have been proposed to overcome limitations of current anti-counterfeiting technologies. Here, we report on artificial fingerprints that can be directly engraved on a wide range of substrates through self-assembled block-copolymer templating as nanoscale PUFs for secure authentication and identification. Results show that morphological features can be exploited to encode fingerprint-like nanopatterns in binary code matrices representing a unique bit stream of information characterized by high uniqueness and entropy. A strategy based on computer vision concepts for authentication/identification in real-world scenarios is reported. Long-term reliable operation and robust authentication/identification against thermal treatment at cryogenic and high temperatures of the PUF have been demonstrated. These results pave the way for the realization of PUFs embracing the inherent stochasticity of self-assembled materials at the nanoscale