Istituto Nazionale di Ricerca Metrologica
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Multipolar Analysis in Symmetrical Meta-Atoms Sustaining Fano Resonances
Get PDFWe present an optical metasurface with symmetrical individual elements sustaining Fano resonances with high Q-factors. This study combines plane-wave illumination and modal analysis to investigate the resonant behavior that results in a suppression of the forward scattering, and we investigate the role of the lattice constant on the excited multipoles and on the spectral position and Q-factor of the Fano resonances, revealing the nonlocal nature of the resonances. The results show that the intrinsic losses play a crucial role in modulating the resonance amplitude in specific conditions and that the optical behavior of the device is extremely sensitive to the pitch of the metasurface. The findings highlight the importance of near-neighbor interactions to achieve high Q resonances and offer an important tool for the design of spectrally tunable metasurfaces using simple geometries
Miglioramento delle capacità di taratura dell'INRIM per tensioni impulsive di origine atmosferica fino a 700 kV
Get PDFLimitations of Bulk Diamond Sensors for Single-Cell Thermometry
Get PDFThe present paper reports on a Finite Element Method (FEM) analysis of the experimental situation corresponding to the measurement of the temperature variation in a single cell plated on bulk diamond by means of optical techniques. Starting from previous experimental results, we have determined-in a uniform power density approximation and under steady-state conditions-the total heat power that has to be dissipated by a single cell plated on a glassy substrate in order to induce the typical maximum temperature increase ΔTglass=1 K. While keeping all of the other parameters constant, the glassy substrate has been replaced by a diamond plate. The FEM analysis shows that, in this case, the maximum temperature increase is expected at the diamond/cell interface and is as small as ΔTdiam=4.6×10-4 K. We have also calculated the typical decay time in the transient scenario, which resulted in τ≈ 250 μs. By comparing these results with the state-of-the-art sensitivity values, we prove that the potential advantages of a longer coherence time, better spectral properties, and the use of special field alignments do not justify the use of diamond substrates in their bulk form
Data for "Quantum Monte Carlo and perturbative study of two-dimensional Bose-Fermi mixtures"
No full textMachine-Learning-Assisted Design of a Robust Biomimetic Radiative Cooling Metamaterial
Get PDFRecently, biomimetic photonic structural materials have significantly improved their radiative cooling performance. However, most research has focused on understanding cooling mechanisms, with limited exploration of sensitive parameter variations. Traditional numerical methods are costly and time-consuming and often struggle to identify optimal solutions, limiting the scope of high-performance microstructure design. To address these challenges, we integrated machine learning into the design of Batocera LineolataHope bionic photonic structures, using SiO2 as the substrate. Deep learning models provided insights into the complex relationship between bionic metamaterials and their spectral response, enabling us to identify the optimal performance parameter range for truncated cone arrays (height-to-diameter ratio (H/D-bottom) from 0.8 to 2.4), achieving a high average emissivity of 0.985. Experimentally, the noon temperature of fabricated samples decreased by about 8.3 degrees C. This data-driven approach accelerates the design and optimization of robust biomimetic radiative cooling metamaterials, promising significant advancements in standardized passive radiative cooling applications
Hydrogen in natural gas grids: prospects and recommendations about gas flow meters
No full textTo inject green hydrogen (H2) into the existing natural gas (NG) infrastructure is one way to decarbonize the European energy system. However, asset readiness is necessary to be successful. Preliminary analysis and experimental results about the compatibility of hydrogen and natural gas mixtures (H2NG) with the actual gas grids make the scientific community confident about the feasibility. Nevertheless, specific technical questions need more research. A significant topic of debate is the impact of H2NG mixtures on the performance of state-of-the-art fiscal measuring devices, which are essential for accurate billing. Identifying and addressing any potential degradation in their metrological performance due to H2NG is critical for decision-making. However, the literature lacks data about the gas meters' technologies currently installed in the NG grids, such as a comprehensive overview of their readiness at different concentrations while data are fragmented among different sources. This paper addresses these gaps by analyzing the main characteristics and categorizing more than 20,000 gas meters installed in THOTH2 project partners’ grids and by summarizing the performance of traditional technologies with H2NG mixtures and pure H2 based on literature review, operators experience and manufacturers knowledge. Based on these insights, recommendations are given to stakeholders on overcoming the identified barriers to facilitate a smooth transition
Hybrid Optical Sensor for Combined Thermal and Dimensional Monitoring in Laser Processing
No full textOptical measurements enable non-contact and high-speed monitoring of physical processes, offering a noninvasive and versatile approach across a wide range of fields, from scientific research to industrial applications. This work presents an optical sensor capable of simultaneously measuring both the distance and thermal emission from surfaces, based on a simple laser diode (LD) probe. The principle of operation integrates triangulation with pyrometry in a single device, leveraging the monitor photodiode (PD) embedded in the probe module. By alternating the probe laser emission, the system can rapidly switch between dimensional and thermal measurements, resulting in combined data acquisition. The proposed method is compact, easy to integrate, and cost-effective. The hybrid sensor is demonstrated in a laser processing setup, where a metallic target is heated and melted by a high-power laser beam. Its inline operation allows for real-time dynamic measurements of melt pool distance and radiance, in a coaxial and self-aligning configuration. This innovative approach can be applied to various fields, such as remote environmental sensing and closed-loop control systems for stabilizing high-temperature processes, including laser welding and additive manufacturing
A Novel Generation and Measurement Setup for the Characterization of MV Voltage Transformers From 9 kHz up to 150 kHz
No full textThis article proposes a generation and measurement setup for the characterization of voltage transformer (VT), both inductive as well as low power voltage transformers (LPVTs) at power frequency and from 9 to 150 kHz with waveforms having amplitudes at medium voltage (MV) level. It involves the independent generation of the fundamental tone and of the high-frequency components to produce the desired distorted test waveform. The generation of the fundamental frequency component, in MV amplitude range, is obtained by means of a step-up VT, whereas the high-frequency components are generated through a series-connected voltage amplifier. As regards the measuring stage, the fundamental tone is measured through a commercial divider. Instead, high-frequency tones are measured through a reference device, operating in the range [9, 150] kHz, specifically designed, realized, and characterized. As an application, the characterization of two commercial VTs, an inductive VT and a LPVT, are presented
Riunione della ISO/TC213 Dimensional and Geometrical Product Specification and Verification – Lund (SE), 2024-09-02/13
No full textPer ragioni di tempo e di spazio, la relazione che segue riguarda la riunione del solo WG 10 CMM. Si rimanda al prossimo numero per gli avanzamenti degli altri Gruppi di Lavoro e della Commissione Tecnica