Istituto Nazionale di Ricerca Metrologica
METRICA Archivio istituzionale della ricerca - INRIMNot a member yet
8322 research outputs found
Sort by
CALIBRATION OF VERY HIGH VALUE RESISTORS D. ISTRATE, E. PATOIS – LNE, TRAPPES I. MIHAI – INRiM, TORINO 23th September 2024
No full textRobust radiative cooling via surface phonon coupling-enhanced emissivity from SiO2 micropillar arrays
Get PDFSilicon dioxide (SiO2) is a prominent candidate for radiative cooling applications due to its low absorption in solar wavelengths (0.25-2.5 μm) and exceptional stability. However, its bulk phonon-polariton band results in a strong reflection peak in the atmospheric transparency window (8-13 μm), making it difficult to meet the requirements for sub-ambient passive radiative cooling. Herein, we demonstrate that SiO2 micropillar arrays can effectively suppress infrared reflection at 8-13 μm and enhance the infrared emissivity by optimizing the micropillar array structure. We created a pattern with a height, spacing, and diameter of approximately 1.45 μm, 0.15 μm, and 0.35 μm, respectively, on top of a bulk SiO2 substrate using reactive ion etching. The resulting surface phonon coupling of the micropillar array led to an increase in the thermal emissivity from 0.79 to 0.94. Outdoor tests show that the SiO2 cooler with an optimized micropillar array can generate an average temperature drop of 5.5 °C throughout the daytime underneath an irradiance of 843.1 W/m^2 at noon. Furthermore, the micropillar arrays endow the SiO2 cooler with remarkable hydrophobic properties, attributed to the formation of F/C compounds introduced during the etching process. Finally, we also replicated the micropillar pattern onto the surface of industrial optical solar reflectors (OSRs), demonstrating similar emissivity and hydrophobicity enhancements. Our findings revealed an effective strategy for modifying the thermal management features of durable SiO2 layers, which can be harnessed to cool OSRs and other similar sky-facing devices
Carbon monoxide proficiency testing scheme with metrological traceability
No full textThis paper details the activities carried out by the Chemical Metrology Department of LATU in the development of a national proficiency testing (PT) scheme aimed at assessing the competence of laboratories in air quality parameters analysis. In this PT scheme, environmental monitoring laboratories were required to determine the concentration of elements in quartz-grade microfiber filters and impinger solutions, as well as to determine the amount fraction of a carbon monoxide in nitrogen gas mixture, within the range of (800 to 1700) mu mol/mol. The focus of the present paper is mainly devoted to the second phase of the test, which addresses the preparation of the gas cylinder distributed to each participant for measurement. A detailed description of this stage is provided, along with the evaluation of the results reported by participating laboratories. This test provided an effective tool for participating laboratories to assess their national technical competence, using their preferred analysis methods
Bilateral comparison of 1.018 V and 10 V standards between INRIM (Italy) and the BIPM, November to December 2023 (part of the ongoing BIPM key comparison BIPM.EM-K11.a and b)
Get PDFBioresorbable multifunctional fiber-optic devices for theranostic and monitoring of tumor
Get PDFCalcium phosphate glass based single-mode and multi-mode bioresorbable optical fibers were in-house manufactured. Ex-vivo studies were then conducted to test the suitability of these fibers for time gated diffuse optics spectroscopy, photodynamic therapy and diffuse correlation spectroscopy applications which can be respectively employed for the diagnosis, treatment, and monitoring of malignant tissues. The results demonstrated the potential of calcium phosphate glass-based fiber optic devices towards the realization of an implantable multi-functional class of devices with functionalities ranging from cancer detection to monitoring of the healing process all integrated into a single bioresorbable platform. Acknowledgement: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 860185
Quantum Monte Carlo and perturbative study of two-dimensional Bose-Fermi mixtures
No full textWe derive analytically the leading beyond-mean-field contributions to the zero-temperature equation of state and to the fermionic quasiparticle residue and effective mass of a dilute Bose-Fermi mixture in two dimensions. In the repulsive case, we perform quantum Monte Carlo simulations for two representative bosonic concentrations and equal masses, extending a method for correcting finite-size effects in fermionic gases to Bose-Fermi mixtures. We find good agreement between analytic expressions and numerical results for weak interactions, while significant discrepancies appear in the regime close to mechanical instability, above which we provide evidence of phase separation of the bosonic component
Laser-frequency stabilization using light shift in compact atomic clocks
Get PDFThis paper describes the light-shift laser-lock (LSLL) technique, an alternative method intended for laser-based compact atomic clocks. The technique greatly simplifies the laser setup by stabilizing the pumping-laser frequency to the same atoms involved in the clock operation, without the need of an external reference. By alternating two clock sequences, the method estimates and cancels out a controlled amount of induced light shift, acting on the laser frequency. The LSLL technique is compatible with state-of-the-art three-level clocks and was demonstrated with field-programmable-gate-array-based electronics on a pulsed-optically-pumped vapor-cell clock developed at INRIM. The results have shown that the LSLL technique operates robustly, having a capture range of gigahertz without significantly compromising clock stability. In our tests, the clock exhibited a white frequency noise of 3.2×10-13τ-1/2 for averaging times τ up to 4000 s, reaching a floor below 1×10-14 up to 100 000 s. This level of performance meets the requirements of future global navigation satellite systems on-board clocks, adding the benefits of a reduced clock footprint, as well as increased reliability and robustness
Traceable Measurements of Mutual Inductance Standards Applied to Large Capacitance Simulation in Electrochemical Impedance Spectroscopy
No full textThis summary paper presents the results for establishing traceable mutual inductance measurements at low frequencies. The measurements performed were validated by comparing the results with an established fully-digital impedance bridge. The use of mutual inductors for the simulation of high capacitance values and its potential use for calibration of electrochemical impedance spectroscopy meters is discussed
Two alternative approaches for the magnetic adsorption of the hydrophobic dye Methylene Blue
Get PDFMany of the most harmful pollutants contained in the wastewaters are hydrophobic compounds. Consequently, the selection of suitable adsorbents to remove Methylene Blue (MB), adopted as model hydrophobic contaminant, was carried out evaluating two alternative approaches. First, two nanocomposites containing the hydrophobic biochar were tested to exploit the hydrophobic interaction between adsorbent and adsorbate. As an alternative approach, a nanocomposite based on chitosan, a material substantially hydrophilic though containing hydrophobic methyl groups, was found to allow adsorption of pollutants by both hydrophobic and hydrogenbond interactions. Both biochar- and chitosan- based nanocomposites were inserted in magnetic nanoparticles by crosslinking and impregnation to allow a simpler solid/liquid separation. XRD, FTIR and SEM analyses elucidated the properties of the nanocomposites, showing the magnetic fraction to be mainly composed of maghemite, with a crystallite size of about 8 mm. The M(H) curves showed a pure superparamagnetic behaviour of the nanoparticles, with larger magnetic moments of biochar nanocomposites in comparison to chitosan nanocomposites (5.8 x 10-20 Am 2 against 3.5 x 10-20 Am 2 ). The mechanism of MB adsorption on the nanocomposites was discussed considering the zero-point charges of nanocomposites and the oxidation -reduction system of MB molecules. The higher adsorption capacity shown by magnetic chitosan in a lower range of MB concentration (1.57 x 10 5 mg/kg) was explained taking into account the overlapping effects of both the hydrophobic and the polar interactions. Kinetics and isotherms modelling suggested a multistep adsorption process, due to the different properties of phases constituting the nanocomposites. An efficient regeneration procedure was developed for the chitosan-based nanocomposite, based on the incubation with an acetic acid/ethanol mixture