1,720,994 research outputs found
Uncertainty analysis of thermal conductivity measurements in materials for energy-efficient buildings
No full textThe accuracy of thermal conductivity measurements is even more requested for materials characterization in energy-efficient buildings field. ENEA-UTTMATF and CertiMaC research group, as national institute and private laboratory respectively, cooperate in development of new measurement and analysis methods applied to buildings materials and their performances. For what concerns this kind of measurements, an Heat Flow-meter Transducer (HFT) is used. In order to give to both customers and other research institutes involved in the same field (e.g. International Comparison or International Round Robin Tests) the most exhaustive evaluation of the tested material thermal conductivity, a complete uncertainty analysis is implemented on the HFT measures. This uncertainty analysis, developed accordingly to the international standards and with the contribution of INRiM Institute, is described in this paper
Uncertainty evaluation of CTD measurements: a metrological approach to water-column coastal parameters in the Gulf of La Spezia area
No full textThe ENEA Marine Environment Research Centre of S. Teresa has been involved since the ‘70s in monitoring, analysis and comprehension of physical, chemical and biological processes in marine environment. The purpose of this work is to describe the recently-implemented metrological approach aimed at evaluating the uncertainty associated with measurements performed by a Conductivity-Temperature-Depth profiler (CTD) during routine coastal campaigns in the Eastern Ligurian Sea, close to the Gulf of La Spezia. Main effort of this work is focused on applying, to each involved parameter, the standard framework for uncertainty evaluation as prescribed by the Guide to the expression of uncertainty in measurement. To this aim, an appropriate uncertainty evaluation is performed by combining type A and B contributions, evaluated from experimental data obtained in reproducibility conditions and from calibration certificates periodically supplied by manufacturer, respectively. Concerning in situ measured practical salinity, probability density functions modelling water pressure, temperature and conductivity, from which salinity depends, are propagated by application of the Monte Carlo method for propagation of distributions, hence obtaining the salinity uncertainty. © 2018 Elsevier Lt
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Assessment of annual physico-chemical variability via high-temporal resolution monitoring in an antarctic shallow coastal site (Terra nova bay, ross sea)
No full textThe Southern Ocean is an important atmospheric carbon sink, and potential changes in the carbon flux in this region will affect the ocean as a whole. Thus, to monitor the variability of its physico-chemical parameters is becoming a priority. This study provides the first high-resolution all-year-round record of observed and computed physico-chemical data from a shallow coastal site in Terra Nova Bay (Ross Sea). From November 2018 to November 2019, an underwater observatory deployed at a 25 m depth under an ice pack recorded pressure (p), temperature (t), electrical conductivity (C), dissolved oxygen (DO), pH in total scale (pHT), and illuminance (Ev). Practical salinity (SP), density (ρ), tidal constituents, carbonate system parameters (total alkalinity (TA), carbon dioxide partial pressure (pCO2 ), calcite, and aragonite (ΩCa, ΩAr )), together with sea ice concentration (SIC) and chlorophyll-a (Chl-a), were derived from measured and satellite data. t, DO, and pHT displayed the lowest values between July and November (–1.95◦C, 6.61 mL L−1, 7.97) whereas the highest in January (+1.08◦C, 10.61 mL L−1, 8.35). SP had the lowest values (33.72 PSU) in February and the highest (34.87 PSU) in September. Ev peaked in March (201 lux), with the highest values (>50 lux) in correspondence to the lowest values of SIC and a delayed trend, between December and March, with respect to Chl-a values (0.2–1.1 mg m−3 ). ΩCa and ΩAr showed their highest average monthly values (±s.d.) in January (ΩCa: 3.41 ± 0.27; ΩAr: 2.14 ± 0.17), when DO had maximum values. The lowest Ω occurred in September (ΩCa: 2.11 ± 0.02; ΩAr: 1.32 ± 0.02), at the end of phytoplankton activity. No undersaturation for both calcite and aragonite was recorded during the study period. This study highlights that biological activities and physico-chemical variables of the investigated shallow coastal site are coupled and, in many cases, influence each other
Reprocessing of eXpendable BathyThermograph (XBT) profiles from the Ligurian and Tyrrhenian seas over the time period 1999–2019 with a full metadata upgrade
Full text linkThe advent of open science and the United Nations Decade of Ocean Science for Sustainable Development are revolutionizing the ocean-data-sharing landscape for an efficient and transparent ocean information and knowledge generation. This blue revolution raised awareness on the importance of metadata and community standards to activate interoperability of the digital assets (data and services) and guarantee that data-driven science preserves provenance, lineage and quality information for its replicability. Historical data are frequently not compliant with these criteria, lacking metadata information that was not retained, crucial at the time of data generation and further ingestion into marine data infrastructures. The present data review is an example attempt to fill this gap through a thorough data reprocessing starting from the original raw data and operational log sheets. The data gathered using XBT (eXpendable BathyThermograph) probes during several monitoring activities in the Tyrrhenian and Ligurian seas between 1999 and 2019 have first been formatted and standardized according to the latest community best practices and all available metadata have been inserted, including calibration information never applied, uncertainty specification and bias correction from Cheng et al. (2014). Secondly, a new automatic quality control (QC) procedure has been developed and a new interpolation scheme applied. The reprocessed (REP) dataset has been compared to the data version, presently available from the SeaDataNet (SDN) data access portal, processed according to the pioneering work of Manzella et al. (2003) conducted in the framework of the European Union Mediterranean Forecasting System Pilot Project (Pinardi et al., 2003). The comparison between REP and SDN datasets has the objective to highlight the main differences derived from the new data processing process. The maximum discrepancy among the REP and SDN data versions always resides within the surface layer (REP profiles are warmer than SDN ones) until 150 m depth generally when the thermocline settles (from June to November). The overall bias and root mean square difference are equal to 0.002 and 0.041 °C, respectively. Such differences are mainly due to the new interpolation technique (Barker and McDougall, 2020) and the application of the calibration correction in the REP dataset. The REP dataset (Reseghetti et al., 2024; https://doi.org/10.13127/rep_xbt_1999_2019.2) is available and accessible through the INGV (Istituto Nazionale di Geofisica e Vulcanologia, Bologna) ERDDAP (Environmental Research Division’s Data Access Program) server, which allows for machine-to-machine data access in compliance with the FAIR (findable, accessible, interoperable and reusable) principles (Wilkinson et al., 2016)
Recent measurements performed by the INRIM fixed-conductance continuous expansion system
No full textIn the last years at IMGC-CNR, a new continuous expansion system, equipped with a fixed conductance, has been designed, assembled and characterized. It replaces the previous system, which was based on the same working principle, but equipped with a variable conductance. The present report aims to describe the most recent checks performed on the new continuous system in order to verify its metrological reliability in the range from 3•10-4 Pa up to 9•10-2 Pa. The first step regards an internal IMGC-CNR comparison with the static expansion system; then the results of a bilateral comparison between NPL and IMGC-CNR (January 2004 - July 2004) are presented and discussed. Finally the measurement procedures and the results of a bilateral comparison NPL–INRIM (June 2005 - August 2005) are presented
Use of ADCP acoustic backscatter to estimate seawater total suspended solids in continuous along a transect. Test case in a near shore area (Ligurian Sea, La Spezia Gulf)
Full text linkAcoustic Doppler Current Profilers (ADCPs), as a secondary output, allow to estimate the concentration of Total Suspended Solids (TSS) in the water column through the analysis of the acoustic backscatter signal. This method was applied during a dedicated ENEA campaign in a near-shore area of the Gulf of La Spezia. ADCP measurements were performed throughout the cruise and joint measurements of TSS (discretely sampled) and Turbidity (by nephelometer) were performed along the water column in one station. The application of the simplified sonar equation made possible to calibrate the ADCP vs TSS by means of a linear regression model, whose correlation coefficient resulted reasonably good (R2 was in fact equal to 0.87), with slope Kc = (0.239 ± 0.008) dB count-1 and intercept Ck = (-69.88 ± 0.59) dB, respectively. The method, whose reliability was proved by comparison with an independent TSS profile, was then applied to obtain a continuous quasi-synoptic mapping of TSS values along the water column throughout the cruise. The overall uncertainty budget of the method was estimated, too: the relative combined standard uncertainty resulted to be less than 30% for TSS values higher than about 3 mg l- 1. The method, although not completely exhaustive due to the multiplicity and unpredictability of the conditions (above all, the type and size and actual distribution of scattering particles), is to be considered valid for a quick acquisition of local situations, allowing to obtain fast and almost zero cost TSS mappings. Results prove that this consolidated approach can be applied in the near-shore area, where ENEA performs its monitoring campaigns and where the interest in TSS measures is also motivated by the presence of fish and mussel farms, the transit of container ships and the proximity of the estuary of the Magra river. The present technical report is intended to serve as a basis for developing procedures more and more compliant to international metrological standards, with the aim of further guaranteeing the metrological traceability of oceanographic quantities
ARGO floats vs. Ship-based CTDs: An overall metrological comparison in the whole Mediterranean Sea
No full textThe widespread network of temperature/salinity profiling floats, known as Argo, has nowadays become a fundamental component of the ocean observing system. Since Argo floats usually are not recovered and should last up to five years without any re-calibration, their onboard sensors can reasonably suffer some drift and/or offset. During the years, very refined methods have been developed and implemented to post-process the Argo data, in order to correct the response of their profiling CTD (Conductivity - Temperature - Depth) sensors, in particular adjusting the salinity drift. The core of this delayed-mode quality control is the comparison of Argo data with reference climatology. At the same time, it's still considered metrologically fundamental the experimental comparison of Argo profiles with quasi-collocated in space and quasi-simultaneous in time ship-based CTD profiles. In this paper an overall comparison of Argo floats vs. shipboard CTDs was made, in terms of temperature and salinity profiles in the whole Mediterranean Sea and under strict space-time matching conditions
Intercomparison of gas flow-rate measurements at IMGC, Italy, and UASG, Germany, in the range from 10(-8) to 10(-3) Pa m(3)/s
No full textPrimary standard gas flow meters are developed for various applications Such as calibration of leak artefacts, generation of calibration pressures by dynamic gas expansion and calibration of secondary standard gas flow meters. The Istituto di Metrologia "G. Colonnetti" (lMGC), Italy, and the University of Applied Sciences Giessen-Friedberg (UASG), Germany, maintain primary flow meters based on different principles in order to measure small gas flows delivered either to vacuum (i.e. practically zero pressure) or to atmosphere (ambient pressure). The principle, design and properties of these flow meters are described. Comparison of the primary standard flow meters maintained at these laboratories was performed over a range from 3 x 10(-8) to 7 x 10(-4) Pa m(3)/s with nitrogen, using a crimped capillary leak as a transfer standard. IMGC was the pilot laboratory. During the intercomparison, the transfer standard changed by ca. -2% for flow to vacuum and by ca. -4% for flow to atmosphere without obvious reason. The results of the intercomparison show that the laboratories agree within their expanded uncertain ties over the measured range of gas flow
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