Istituto Nazionale di Ricerca Metrologica
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On the metrological reliability of subsequent verification of thermal energy meters
No full textIndividual metering for heating and cooling has been recognized by EU as an effective tool to improve energy efficiency. Hence, thermal energy meters are widely spreading in district heating networks and in buildings. While type approval and initial verification of thermal energy meters are clearly regulated, no technical stan-dards are available in EU for subsequent verification both in laboratory and in-field. Nevertheless, verification of thermal energy meters is a difficult task, due to the complex measuring chain and to the need to set appropriate verification points combined in flow-rate and temperature difference. In this paper, the authors present the results of an experimental campaign aimed at analysing the metrological issues and compatibility between subsequent verification of a thermal energy meter performed in the laboratory and in-field. The obtained results demonstrate that in-field verification outcomes in some cases are not consistent with the in-laboratory ones
Characterization of Instrument Transformers under Realistic Conditions: Impact of Single and Combined Influence Quantities on Their Wideband Behavior
Get PDFInstrument transformers (ITs) play a key role in electrical power systems, facilitating the accurate monitoring and measurement of electrical quantities. They are essential for measurement, protection, and metering in transmission and distribution grids and accurately reducing the grid voltage and current for low-voltage input instrumentation. With the increase in renewable energy sources, electronic converters, and electric vehicles connected to power grids, ITs now face challenging distorted conditions that differ from the nominal ones. The study presented in this paper is a collaborative work between national metrology institutes and universities that analyzes IT performance in measuring distorted voltages and currents in medium-voltage grids under realistic conditions. Both current and voltage measuring transformers are examined, considering influence quantities like the temperature, mechanical vibration, burden, adjacent phases, and proximity effects. The study provides detailed insights into measurement setups and procedures, and it quantifies potential errors arising from IT behavior in measuring distorted signals in the presence of the various considered influence quantities and their combinations. The main findings reveal that the temperature has the most evident impact on the inductive voltage transformer performance, as well as the burden, causing significant changes in ratio error and phase displacement at the lower temperatures. As for low-power ITs, establishing a priori the effects of adjacent phases and proximity on the frequency responses of low-power ITs is a complex matter, because of their different characteristics and construction solutions
A contribution to trustworthiness of data from digital MEMS accelerometers for smart mobility
Get PDFAb initio study of magneto-ionic mechanisms in ferromagnet/oxide multilayers
Get PDFThe application of gate voltages in heavy metal/ferromagnet/oxide multilayer stacks has been identified as one possible candidate to manipulate their anisotropy at will. However, this method has proven to show a wide variety of behaviors in terms of reversibility, depending on the nature of the metal/oxide interface and its degree of oxidation. In order to shed light on the microscopic mechanism governing the complex magneto-ionic behavior in Ta/CoFeB/HfO2, we perform ab initio simulations on various setups comprising Fe/O and Fe/HfO2 interfaces with different oxygen atom interfacial geometries. After the determination of the more stable interfacial configurations, we calculate the magnetocrystalline anisotropy energy on the different unit cell configurations and formulate a possible mechanism that well describes the recent experimental observations in Ta/CoFeB/HfO2
Report from inter-laboratory comparison of air thermometer calibration procedures. EURAMET project 1459
Get PDF1 Objective
The main objective of this comparison is to identify unwanted influences on air temperature
measurements, and to provide a basis for recommendations to laboratories that offer air
temperature calibrations, or in some way use air temperature measurements as important auxiliary
information during other calibrations.
It is well known that a host of issues affect the heat transfer between a thermometer and air, such as
wind speed, sensor irradiation, air pressure and humidity. A previous EURAMET comparison, P1061,
concluded that radiation shielding might alleviate errors due to purely radiative heat loads, but
exacerbate errors related to conductive and convective heat transfer (1). However, recent work by
de Podesta et al (2) suggests a more insidious connection between the heat transfer properties at the
sensor interface, by pointing to an interplay between sensor dimension, wind speed and irradiation.
Controlled experiments showed that the magnitude of the discrepancy between thermometer
reading and actual air temperature can be of concern even in highly controlled laboratories.
This comparison aims to gain further insight into the ways air temperature measurements can be
affected by collecting measurements from a number of laboratories employing different techniques
to assess air temperature. The data will be used to compute the degree of equivalence (DoE) for the
participants using a consensus based reference value, but also to analyse reasons for disparities
between laboratories. In addition to the common set of reported results which all participants will be
required to supply, some participants will conduct additional measurements that will be taken into
account in the analysis.
While the primary aim of the ILC is to conduct research it is still vital that participants do not share
results during the measurements. Once all the data have been collected the pilots and the
coordinator will analyse the data and prepare a report, and from that point the data will be open to
all participants
Acoustic thermodynamic calibration of capsule-type standard resistance thermometers between 10 K and 25 K
Get PDFFiber-Based SERS-Fluidic Polymeric Platforms for Improved Optical Analysis of Liquids
Get PDFDownsizing surface-enhanced Raman spectroscopy (SERS) within microfluidic devices has opened interesting perspectives for the development of low-cost and portable (bio)sensors for the optical analysis of liquid samples. Despite the research efforts, SERS-fluidic devices still rely either on the use of expensive bulky set-ups or on polymeric devices giving spurious background signals fabricated via expensive manufacturing processes. Here, polymeric platforms integrating fluidics and optics were fabricated with versatile designs allowing easy coupling with fiber-based Raman systems. For the first time, anti-fouling photocurable perfluoropolyether (PFPE) was explored for high-throughput SERS-integrating chip fabrication via replica molding of negative stamps obtained through standard and advanced fabrication processes. The PFPE devices comprised networks of channels for fluid handling and for optical fiber housing with multiple orientations. Embedded microfeatures were used to control the relative positioning of the fibers, thus guaranteeing the highest signal delivering and collection. The feasibility of PFPE devices as fiber-based SERS fluidic platforms was demonstrated through the straightforward acquisition of Raman-SERS spectra of a mixture of gold nanoparticles as SERS substrates with rhodamine 6G (Rh6G) at decreasing concentrations. In the presence of high-performing gold nanostars, the Rh6G signal was detectable at dilutions down to the nanomolar level even without tight focusing and working at low laser power-a key aspect for analyte detection in real-world biomedical and environmental applications
