Development of testing protocols for the measurement of pure and blended hydrogen in natural gas grids: An outlook from the THOTH2 project

Transporting or blending hydrogen (H2) into the existing gas infrastructure can be crucial in the European green transition. However, the regulation of this matter is still debated by interested stakeholders. The THOTH2 project aims to fill normative gaps by developing new protocols for assessing the limits and tolerances of state-of-the-art (SoA) instrumentation installed in natural gas (NG) transmission and distribution grids. This paper outlines the methodology used for selecting the devices and establishing the testing protocols for the various categories of instruments. These instruments are scheduled for experimental testing in the subsequent phase of the project

Metrological traceability of moisture/water content measurements

This paper explains advantages and disadvantages of the measurement methods for moisture and water content determinations in plant-based materials, in order to identify the method providing the best metrological features. The term “moisture” is generic and it does not identify a specific measurand. In this sense, to declare proper Calibration and Measurement Capabilities (CMCs) and to develop Certified Reference Materials (CRMs), a better specification of the measurand should be given. Currently, no CMCs for moisture or water content measurements in the plant-origin bulk materials, as well as respective CRMs, are available in the Key Comparison Database (KCDB) published on the website of the Bureau International del Poids et Mesures (BIPM). Undoubtedly, those CMCs and CRMs, characterised for water content, are crucial and essential to provide metrological traceability of measurement results for the quality assessment of plant-origin bulk materials in the agricultural sector

Enhanced Photoluminescence in a Neuromorphic 2D Memitter Based on WS2 via Plasmonic Nanoparticle Self-Assembly

All-optical neuromorphic devices based on adaptive two-dimensional (2D) materials have the potential for mimicking the complex processing and memory capabilities of biological synapses. Recent research demonstrated synaptic plasticity and visual memory in WS2 monolayer-based 2D memitters (i.e., an emitter with memory). However, improving their optical performances is crucial for extending their scalability. Since the neuromorphic functionalities of 2D memitters relies on O2 and H2O desorption/absorption on WS2, a careful balance between photoluminescence intensity and surface preservation is critical. Here, we investigate the enhancement of time-dependent photoluminescence response, achieved through coupling WS2 flakes with plasmonic nanoparticles obtained by liquid phase infiltration of gold in self-assembled block copolymer micelles. The localized surface plasmon resonance of gold nanoparticles amplifies the electric field and improves light-matter interactions. This method enhances the 2D memitter optical properties while preserving its adaptive photoluminescence response, thus enabling neuromorphic behavior under optical stimuli

Characterization of plant pathogenic bacteria at subspecies level using a dielectrophoresis device combined with Raman spectroscopy

Timely diagnosis of plant diseases and correct identification of etiological agents are fundamental to guarantee quality and quantity of agricultural products and food. Phytopathogenic bacteria induce devastating effects on crops. Their diagnosis and identification, mainly based on serological and molecular tools, are time consuming and expensive processes and require trained personnel. Among the innovative methods providing rapid, accurate, and reliable diagnosis at reduced costs, Raman spectroscopy (RS) is gathering considerable attention. RS provides a direct and non-destructive platform to gather information on the chemical and biochemical components of a sample, such as microorganism cultures, revealing their biological role. Due to the weak signals of bacterial cells in RS, a dielectrophoresis (DEP) approach was adopted to amplify the bacterial signals. Using Raman-DEP analysis, a dataset of spectra from different harmful phytopathogenic bacteria belonging to the genera Pseudomonas spp., Xanthomonas spp., and Erwinia spp. was obtained. Machine learning approaches were employed to discriminate isolates at the genus, species, and unprecedentedly at the pathovar level, reaching accuracies, precisions, recalls, and F1 scores of 94–100%. This approach offers important advancements in the non-destructive and rapid classification of microorganisms and is suitable to be readily extended to environmental and food diagnostics

Rules for Monte Carlo simulations through anomalous heterogeneous media

Until now, when describing transport through the vast class of anomalous media, researchers always assumed that it was sufficient to simply replace the classical step length distribution with an anomalous one of choice. The presented results reveal that this is not sufficient, leading to macroscopic violations of multiple physical quantities that were not recognized in the previous literature. In anomalous transport, light acquires a "memory"of its past trajectory, which requires the introduction of new rules for its propagation-especially when crossing boundaries between different regions. This work successfully identiffies the complete set of rules-a "recipe"for the correct modeling of anomalous light transport-validating it in a range of different scenarios and revealing some counter-intuitive consequences of its application to the case of finite heterogeneous media. These results represent a generalization of classical transport that can also be applied to all types of anomalous transport beyond light and optics, offering insights on both its physical interpretation and expected impact on experimental measurements

Surface slope measurement of steep silicon V-grooves using high NA Linnik interferometry

Optical topography measurements are of high interest in a lot of industrial and academic fields. One of the most common associated measurement methods is coherence scanning interferometry, but even though it provides sub-nanometer axial resolution, its lateral resolution is diffraction limited. Not only the feature size is a limiting factor for optical measurements, but also steep surface slopes may lead to problems, since the acceptance angle of the objective lens limits the maximum surface slope angles that can be measured. Here we use a Linnik-type interferometer with objective lenses of numerical apertures of 0.95 in order to maximize the measurable surface slope angle. We demonstrate that silicon V-groove structures with a slope angle of 54.74° can be measured. We compare the directly measured surface slope angle with an angle calculated from light that is reflected two times by the V-grooves. To verify our measurement we compare the measurement results to rigorous FEM simulations

An efficient computational model for single-molecule optoelectronic devices

The growing interest in tuning the conduction properties of single-molecule junctions has drawn attention to studying their interaction with incident electromagnetic fields. The theoretical complexity of this problem necessitates the use of nonequilibrium statistical mechanics combined with quantum electrodynamics, leading to extremely time-consuming simulations. In this work, we propose a computationally efficient algorithm, which combines EE-BESD—an efficient and effective simulator of current–voltage characteristics in dark conditions—with approximated models for light interaction, specifically the Tien-Gordon and Floquet models. We validate EE-BESD-PAT through comparison with ab initio calculations and experimental data from the literature. Our computational model demonstrates good agreement with both experimental and density functional theory calculations, demonstrating that the proposed method is a promising computationally efficient tool without sacrificing accuracy

Automated DC voltage and DC resistance real-time multiple standard for artifact calibration of calibrators and multimeters

An automated temperature-controlled electrical DC voltage and DC resistance multiple reference standard (MRS) has been developed by Measurements International (MI) with the scientific support from the Istituto Nazionale di Ricerca Metrologica (INRIM). The MRS includes a 10V, a 1Ω, and a 10 kΩ standards selectable via a switch unit. This setup allows the artifact calibration of high-end calibrators and multimeters used in low-frequency electrical measurements. The two resistors are high-stability standards from MI, while the 10V standard is based on a low-noise circuit developed by INRIM in collaboration with MI. A key innovation is the internal real-time clock calendar, which displays the calibration values of the MRS standards and their updated values internally calculated. This ensures reliable use of the MRS standards over extended periods between calibrations, effectively minimizing uncertainties due to their drift. The standards are housed in a thermal box, minimizing temperature variations. The MRS standards meet the uncertainty requirements defined by calibrators and multimeters manufacturers for artifact calibration and can also serve as laboratory references or travelling standards for interlaboratory comparisons (ILCs). MI is currently commercializing the MRS

Effectiveness of Sound Field Corrections for High-Frequency Pressure Comparison Calibration of MEMS Microphones

The calibration of Micro-Electro-Mechanical System (MEMS) microphones remains a critical challenge due to their miniaturized geometry and sensitivity to non-uniform acoustic fields. This study presents an advanced calibration methodology that integrates Finite Element Method (FEM) simulations with experimental corrections to improve the accuracy of pressure comparison calibrations using active couplers. A key innovation is the incorporation of asymmetric acoustic field analysis, which systematically quantifies and corrects discrepancies arising from cavity geometry, sensor positioning, and resonance effects peculiar of MEMS microphones. The proposed approach significantly reduces measurement uncertainties, especially in the high-frequency range above 5 kHz, where standard calibration techniques face challenges in taking into account localized pressure variations. Furthermore, the implementation of a measurement set-up, which includes the insert voltage technique, allows for an accurate assessment of the preamplifier gain and minimizes systematic errors. Experimental validation shows that the refined calibration methodology produces highly reliable correction values, ensuring a robust performance over a wide frequency range (20 Hz–20 kHz). These advances establish a rigorous framework for standardizing the calibration of MEMS microphones, strengthening their applicability in acoustic monitoring, sound source localization, and environmental sensing

Comparison between an optical pressure standard based on multi-reflection interferometric technique and conventional primary standards

An optical pressure standard, based on a multi-reflection interferometric technique, has been recently developed. This quantum-based standard realizes the pascal through the measurement of the refractive index of a gas by an unbalanced homodyne interferometer and it is currently capable of measuring gas pressure with a relative uncertainty of 10 ppm at 100 kPa. The performance of such optical-based standard have been preliminary evaluated by comparing it with two conventional primary pressure standards, namely a force balanced piston gauge and a pressure balance, in the range from 400 Pa to 120 kPa. This work describes the performed study and discusses the results, which demonstrated the agreement between the optical pressure standard and the conventional standards in the considered range, within their related uncertainties (k = 1)