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NRIM-BIPM.EM-K13.a and b Key Comparisons of Electrical Resistance Standards using 1 Ω and 10 kΩ Resistors as Travelling Standards: INRIM results
Get PDFThe technical report summarizes the results provided by the Resistance laboratory of the National Research Institute (INRIM) concerning the calibration of two 1 Ω and two 10 kΩ standard travelling resistors related to the comparison BIPM.EM-K13.a (1 Ω resistance standards) and BIPM.EM-K13.b (10000 Ω resistance standards) which constitute the BIPM programme of on-going bilateral comparisons of resistance standards. The chosen resistors normally assure a transfer uncertainty less than a few parts in 108. The comparison was carried out following an initial/return measurement pattern: the BIPM travelling standards were first calibrated at the BIPM then they were sent to INRIM where they were calibrated, and finally re-calibrated after their return at the BIPM. All measurement results will be corrected to the reference temperature (23.000 °C) and the reference pressure (1013.25 hPa). The result of the comparison will be expressed as the difference between the calibrations from the two laboratories, together with its associated uncertainty. The pilot laboratory was the BIPM
Reference materials: gas mixtures to support measurements for climate change studies
No full textThis work aims at presenting some activities carried out at INRiM for the
development of new reference materials (RMs) of greenhouse gases to support measurements
for climate change studies. Since the preindustrial era, greenhouse gases emissions due to
human activities have dramatically increased, mostly due to economic and demographic
growth and their concentrations in the atmosphere have grown continuously since 2011,
reaching highest levels in 2019. The increase of greenhouse gases concentration in atmosphere
due to anthropogenic emissions is the main cause of global warming and carbon dioxide (CO2)
is one of the main culprits for this phenomenon. In this context, the capability of discriminating
between anthropogenic and natural emissions is of utmost importance. The determination of
the isotopic composition of CO2 can support the assessment of the uptake of CO2 in the
environmental compartments, i.e. atmosphere and hydrosphere, and can help to distinguish
natural from anthropogenic carbon in the atmosphere. The possibility to establish metrological
traceability of the measurements of CO2 isotopic composition is a key aspect, and greatly relies
on the availability of gaseous reference materials having compositions and uncertainties that
are fit for purpose. In the past years, INRiM participated in the EMPIR project 16ENV06 SIRS
“Metrology for stable isotope reference standards”, and is now taking part in the EMPIR
project 19ENV05 STELLAR “Stable isotope metrology to enable climate action and
regulation”. INRiM has experience in the preparation of gas standards by primary methods,
namely gravimetry and dynamic dilution, which can be applied to the realisation of reference
materials of CO2 at known isotopic composition. The present work describes the preliminary
results obtained by INRiM in the preparation of pure CO2 RMs and at atmospheric amount
fraction. Examples of uncertainty budgets and identification of the uncertainty sources are also
given
Laser-induced graphene as a sustainable counter electrode for DSSC enabling flexible self-powered integrated harvesting and storage device for indoor application
No full textDye-sensitized solar cells (DSSCs) are gaining a newfound interest thanks to their superior ability to harvest
indoor light with efficiency higher than other photovoltaic technologies. This study reports, for the first time, the
possibility of using laser-induced graphene (LIG) as a flexible counter electrode material for DSSCs. A flexible LIG
(F-LIG) electrode was fabricated by direct laser writing of a polyimide film, without the need of a starting
conductive substrate. The prepared electrodes showed a higher catalytic activity towards the reduction of I3
− /
I
− with respect to a more expensive Pt-based counter electrode. Moreover, the F-LIG electrodes outperformed
electrodeposited PEDOT as a catalytic material for reduction of a copper bipyridyl complex (Cu(II/I)(tmby)2TFSI2/
1) electrolyte. The F-LIG based DSSCs showed an open circuit voltage as high as 0.94 V and an increase in
photoconversion efficiency higher than 60% with respect to the PEDOT-based counterpart, stepping from 3.08%
to 4.96%. Thanks to the easy one-step laser-based fabrication process, the LIG-based DSSC was integrated with a
LIG-based supercapacitor (SC), obtaining a flexible energy harvesting and storage system that was able to selfcharge both under simulated solar illumination and under indoor artificial illumination, appearing to be a
promising energy source for the next generation of self-powered connected Internet of Things device
Crystal bending in triple-Laue X-ray interferometry. Part II. Phase-contrast topography
Get PDFIn a previous paper [Sasso et al. (2023). J. Appl. Cryst. 56, 707-715], the operation of a triple-Laue X-ray interferometer having the splitting or recombining crystal cylindrically bent was studied. It was predicted that the phase-contrast topography of the interferometer detects the displacement field of the inner crystal surfaces. Therefore, opposite bendings result in the observation of opposite (compressive or tensile) strains. This paper reports on the experimental confirmation of this prediction, where opposite bendings were obtained by copper deposition on one or the other of the crystal sides
Atomistic to Mesoscopic Modelling of Thermophysical Properties of Graphene-Reinforced Epoxy Nanocomposites
Get PDFThis research addresses the need for a multiscale model for the determination of the thermophysical properties of nanofiller-enhanced thermoset polymer composites. Specifically, we analyzed the thermophysical properties of an epoxy resin containing bisphenol-A diglyceryl ether (DGEBA) as an epoxy monomer and dicyandiamide (DICY) and diethylene triamine (DETA) as cross-linking agents. The cross-linking process occurs at the atomistic scale through the formation of bonds among the reactive particles within the epoxy and hardener molecules. To derive the interatomic coarse-grained potential for the mesoscopic model and match the density of the material studied through atomic simulations, we employed the iterative Boltzmann inversion method. The newly developed coarse-grained molecular dynamics model effectively reproduces various thermophysical properties of the DGEBA-DICY-DETA resin system. Furthermore, we simulated nanocomposites made of the considered epoxy additivated with graphene nanofillers at the mesoscopic level and verified them against continuum approaches. Our results demonstrate that a moderate amount of nanofillers (up to 2 wt.%) increases the elastic modulus and thermal conductivity of the epoxy resin while decreasing the Poisson's ratio. For the first time, we present a coarse-grained model of DGEBA-DICY-DETA/graphene materials, which can facilitate the design and development of composites with tunable thermophysical properties for a potentially wide range of applications, e.g., automotive, aerospace, biomedical, or energy ones
Dy3+-doped phosphate glass optical fibers for 577 nm wavelength fiber lasers
Get PDFLasers emitting in the visible find applications in biology and medicine. Considering the success of near-infrared fiber lasers, the possibility to optically pump rare-earth-doped fibers in the blue to directly obtain visible emission is attractive. The recent progress in the field of GaN-based blue laser diodes offers new scopes. Dy3+-doped materials have received much interest because of their intense yellow emission originating from the 4F9/2→6H13/2 transition. An involvement of a glass matrix benefiting from enhanced thermo-mechanical properties would ease diode pumping. We report on the synthesis of a series of novel phosphate glasses in the system P2O5-Al2O3–BaO-K2O doped with Dy2O3. The Dy3+ concentrations were 0.05, 0.21, 0.83 and 2.5 [1020 ions/cm3]. The glasses were synthesized by the standard melt-quenching technique and thoroughly characterized in their physical, thermo-mechanical and optical properties. A Dy3+-doped optical fiber was drawn by preform drawing from the developed glasses, with the preform being obtained by rod-in tube technique, combining a cast core and an extruded cladding. Preliminary emission results in the visible from the fabricated fiber will be reported
Intervista a Dario Mirabelli (a cura di E. Ferrara) - dal convegno "Amianto e Mesotelioma: tutti innocenti? Aspetti biologici ed epidemiologici dell’esposizione ad amianto e conseguenze giuridiche", Roma, 13 maggio 2022
Get PDFGiustizia o ingiustizia? era il titolo di un convegno organizzato a Roma nel settembre 2016 dalle associazioni delle vittime di amianto in Italia. Le motivazioni che avevano spinto a indire quell’evento sono purtroppo ancora valide: nel nostro paese quasi tutti i procedimenti penali per casi di patologie professionali o decessi dovuti a esposizione all’amianto continuano a concludersi con assoluzioni, per la pretesa impossibilità di individuare i soggetti a garanzia responsabili dell’esposizione professionale o ambientale che ha causato l’insorgenza della malattia. Come sia possibile che questo continui ad accadere è stato argomento di dibattito anche durante il più recente convegno Amianto e Mesotelioma: tutti innocenti? Aspetti biologici ed epidemiologici dell’esposizione ad amianto e conseguenze giuridiche tenutosi a Roma in una Sala Capitolare del Senato il 13 maggio 2022, promosso dalla senatrice Tatjana Rojc in collaborazione con AIEA, AFEVA, AICA, ARASIS, Federazione Nazionale Pro Natura, Gruppo Aiuto Mesotelioma, ISDE, Legambiente, Medicina Democratica ed Epidemiologia & Prevenzione. Gli amianti sono noti e utilizzati da migliaia di anni anche se il loro impiego industriale risale solo agli ultimi 150 anni
On the calibration of DC resistance ratio bridges
Get PDFCurrent comparator bridges are employed for the realization of the resistance scale from the quantum Hall effect in several National Metrology Institutes and calibration centers. Quantum resistance standards under development, based on novel materials and tabletop dry cryostats, make the more achievable DC current comparator bridges (DCCs) a viable alternative to the more accurate but more expensive cryogenic current comparator bridges (CCCs). A DCC ratios' calibration against a reference CCC is a straightforward way to improve the DCC's performances and the resistance scale overall accuracy.The paper reports the calibration results of two DCCs on the ratios employed in a 1 omega to 10 k omega resistance scale traceable to a 12.906 k omega quantized Hall resistance, showing a good reproducibility and stability of the DCC readings over the measurement period and supporting the possibility of a DCC errors' correction and of a realization of the primary resistance scale at the 10-8 level
Development and Metrological Characterization of a Multi-sensor Device for Indoor Environmental Quality (IEQ) monitoring
No full textIndoor Environmental Quality (IEQ), which affects people's health, comfort, well-being and productivity, combines thermal, visual, acoustic and air quality conditions. This work deals with design, development and metrological characterization of a low-cost multi-sensor device that is able to detect the quality conditions of indoor environments for IEQ purposes. The device, hereafter referred as PROMET&O (PROactive Monitoring for indoor EnvironmenTal quality & cOmfort) embeds a set of low-cost sensors that measure air temperature and relative humidity, illuminance, sound pressure level, carbon monoxide, carbon dioxide, particulate matter, formaldehyde, and nitrogen dioxide. The basic architecture of the device is described and the design criteria that are related to the measurement requirements are highlighted. Particular attention has been paid towards the traceability assurance of the measurements provided by PROMET&O by means of specifically conceived calibration procedures, which have been tailored to the requirements of each measurement quantity. The calibration is based on the comparison to reference standards following commonly employed or ad-hoc developed technical procedures. The defined calibration procedures can be applied both for the single sensors and for the set of sensors integrated in the multi-sensor case. For the latter, the effects of the percentage of permeable case surface and the sensors allocation are also investigated. A preliminary uncertainty evaluation of the proposed multi-sensor device is reported for the carbon dioxide and the illuminance sensors taking the defined calibration procedures into account