Istituto Nazionale di Ricerca Metrologica
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Thermodynamic and metrological issues in environmental measurements
No full textEnvironmental measurements represent a phenomenal societal and scientific challenge of ever-growing importance in the light of the ongoing and future climate variability. Thermal quantities (air, sea, snow and soil temperature, humidity, permafrost depth) are key among the Essential Climate Variables (ECVs) as defined by the WMO Global Climate Observing System in these areas. In order to accurately capture climatic trends and enable early detection, metrological rigor in terms of sensor calibration and uncertainty budget evaluation are of paramount importance. For this reason, the metrology and meteo/climatic communities have started a decade-long ongoing cooperation through the mutual recognition accords between the WMO and BIPM, which led to the exchange of representatives in WGs, the co-hosting of a series of joint workshops (“Metrology for Climate Action”), and a general strict cooperation, through the development of new measurement techniques and instruments; the understanding of uncertainty components both for laboratory calibration and for field conditions; the accurate evaluation of quantities of influence; and the development guidelines, best practices and recommendations
Realizzazione e confronto di scale di radianza a 650 nm e 900 nm tra 960 °C e 2100 °C con i termometri: Chino IR-RST65H e Chino IR-RST90H.
No full textThe Primary Standard Radiation Thermometry Labs of INRiM has recently adopted two high quality commercial type radiation thermometers to be used as primary and transfer standard instruments, respectively. The first instrument will be employed for the realization of the International Temperature Scale (ITS-90) in the temperature range between 960 °C and 2800 °C and the second device for the approximation and dissemination of traceability in the temperature range from 420 °C and 2100 °C.
This technical report describes the measurement processes that led to the primary calibration of both thermometers. The first one according to the requirements allowed for the implementation of the ITS-90 and the second according to the fixed-points method (Zn, Al, Ag and Cu) as well as the results obtained in the direct comparison of the two radiance scales realized in the temperature range between 960 °C and 2100 °C
Mean Field Theory of Self‐Organizing Memristive Connectomes
No full textBiological neuronal networks are characterized by nonlinear interactions and complex connectivity. Given the growing impetus to build neuromorphic computers, understanding physical devices that exhibit structures and functionalities similar to biological neural networks is an important step toward this goal. Self-organizing circuits of nanodevices are at the forefront of the research in neuromorphic computing, as their behavior mimics synaptic plasticity features of biological neuronal circuits. However, an effective theory to describe their behavior is lacking. This study provides for the first time an effective mean field theory for the emergent voltage-induced polymorphism of circuits of a nanowire connectome, showing that the behavior of these circuits can be explained by a low-dimensional dynamical equation. The equation can be derived from the microscopic dynamics of a single memristive junction in analytical form. The effective model is tested on experiments of nanowire networks and show that it fits both the potentiation and depression of these synapse-mimicking circuits. It is shown that this theory applies beyond the case of nanowire networks by formulating a general mean-field theory of conductance transitions in self-organizing memristive connectomes
Parasitic load components for torque and force calibration: a Digital Twin concept
Get PDFThe 5 MN m standard torque machine within the Competence Centre for Wind Energy (CCW) was developed at PTB. The Digital Twin (DT) of the torque transducer mounted inside the machine was developed to enable errors eliminations and resources optimization during operation. The machine can apply not only torque, but also bending moments and shear forces. At the same time, the DT concepts of force measurement devices and their application for static, continuous and dynamic calibrations was developed to improve calibration processes, preserve data quality and collect calibration data for improved decision making. In order to illustrate the functionality of both developed DT concepts, a study of parasitic load components in both devices is carried out using simulation with ANSYS and ABAQUS engineering software. The validation of the DT models was carried out using traceable measurements. The way to combine both concepts for comprehensive shading of the standard torque machine is discussed
Impatto dei Trasformatori Voltmetrici nella Misura delle Subarmoniche di Rete in Accordo con le Norme Internazionali
Get PDFAirborne sound transmission loss of ship bulkheads: A new methodological approach for in-laboratory assessment by including low frequencies
No full textCurrent standard laboratory measurements of sound transmission loss properties of ship bulkheads at low frequencies, below 100 Hz, are not accurate enough due to the non-diffuse acoustic field of typical laboratory volumes. However, what has been recently observed in non-diffuse field conditions is the transmission of source modes into the receiving room through the partition. On the basis of this, in this paper, a novel procedure to determine the laboratory airborne sound transmission loss properties of ship bulkheads at low frequencies through the airborne modal sound transmission loss is investigated. It is defined as the difference between the average sound pressure levels of source room modes peaks that occur in both source and receiving rooms. A correction method is proposed to suppress the influence of natural receiving room modes. Normalization terms related to receiving room volume and modal damping are introduced, and an envelope method is applied to extend the results in third octave bands. Measurements on five different ship bulkheads show that the standard transmission loss in the low frequency range provides unlikely results, whereas the proposed descriptor follows the expected theoretical curve. This evidence confirms the validity of the proposed method, at least for comparison purposes in marine applications
