Analysis of performance characteristics in ground effect of a large scale V/STOL multi-fan-in-wing transport model

Performance characteristics from static tests in ground effect of V/STOL transport mode

Internal reflections and nonlinear effects interplay in non-ideal Josephson Travelling Wave Parametric Amplifiers

The paper investigates the interplay of nonlinear effects with the non-ideal transmission properties of a Josephson Travelling Wave Parametric Amplifier (JTWPA). Experimental characterization using a microwave and DC cryogenic setup reveals periodic transmission modulation linked to the tuning of the Josephson inductances embedded in the line. The effects of impedance matching and resonant parametric down-conversion (PDC) are observed on a broadband scale, and the impact of de sign parameters and fabrication issues on device performance is analyzed. These findings contribute to the optimizing techniques for JTWPA devices, advancing quantum-limited amplifiers

ILC EM-RF01/2021 Parametri “S” in connessione N 100 kHz - 18 GHz Rapporto finale

Questo rapporto tecnico presenta i risultati finali di un Confronto Interlaboratorio nell’Area Metrologica Elettricità e Magnetismo – Grandezza: Parametri di Scattering (Parametri “S”) ovvero Coefficiente di Riflessione e Coefficiente di Trasmissione/Attenuazione a radiofrequenza in linea coassiale con connettori di tipo “N” nel campo di frequenza da 100 kHz a 18 GHz, codice Identificativo ILC: EM-RF01/2021. Si tratta di un confronto nazionale di misura (ILC) in accordo con la norma EN ISO/IEC 17043:2010, effettuato nell’anno 2021 e destinato a quattro Laboratori nazionali accreditati, due dei quali hanno sottoposto al confronto due sistemi di misura diversi, per un totale di sei confronti effettivi.This technical report outlines the conclusive findings from an Interlaboratory Comparison within the Electricity and Magnetism Metrological Area. The focus was on Scattering Parameters ("S" Parameters), encompassing Reflection Coefficient and Radio Frequency Transmission/Attenuation Coefficient, measured in coaxial lines with "N" type connectors across the frequency spectrum of 100 kHz to 18 GHz. The assigned ILC identification code is EM-RF01/2021. Conducted in 2021, this national measurement comparison (ILC) adheres to the EN ISO/IEC 17043:2010 standard. It involved four accredited national laboratories, two of which submitted two distinct measurement systems for comparison, resulting in a total of six actual comparisons

Conferma Metrologica 2024 del Sistema di misura dei Parametri “S” in connessione 2.92mm e nel campo di frequenza da 9 kHz a 3 GHz

In questo rapporto tecnico si descrivono le operazioni di Conferma Metrologica del Sistema di misura dei Parametri “S” in connessione 2.92mm nel campo di frequenza da 9 kHz a 3 GHz. Il risultato di queste operazioni è la determinazione dell’Indice di Compatibilità che, se ≤ 1 in valore assoluto, valida il sistema di misura INRIM.This technical report describes the operations of Metrological Confirmation for the "S” Parameters measurement system in 2.92mm connection, in the frequency range from 9 kHz to 3 GHz. The result of these operations is the determination of the Compatibility Index which, if ≤ 1 in absolute value, validates the INRIM measurement system

ILC EM-RF02/2021 Parametri “S” in connessione 3.5mm 100 kHz – 26.5 GHz Rapporto finale

Questo rapporto tecnico presenta i risultati finali di un Confronto Interlaboratorio nell’Area Metrologica Elettricità e Magnetismo – Grandezza: Parametri di Scattering (Parametri “S”) ovvero Coefficiente di Riflessione e Coefficiente di Trasmissione/Attenuazione a radiofrequenza in linea coassiale con connettori di tipo “3.5mm” nel campo di frequenza da 100 kHz a 26,5 GHz, codice Identificativo ILC: EM-RF02/2021. Si tratta di un confronto nazionale di misura (ILC) in accordo con la norma EN ISO/IEC 17043:2010, effettuato nell’anno 2021 e destinato a tre Laboratori nazionali (LAT), due dei quali con sistema di misura accreditato ed il terzo con sistema di misura non accreditato.This technical report outlines the conclusive findings from an Interlaboratory Comparison within the Electricity and Magnetism Metrological Area. The focus was on Scattering Parameters ("S" Parameters), encompassing Reflection Coefficient and Radio Frequency Transmission/Attenuation Coefficient, measured in coaxial lines with "3.5mm" type connectors across the frequency spectrum of 100 kHz to 26,5 GHz. The assigned ILC identification code is EM-RF02/2021. Conducted in 2021, this national measurement comparison (ILC) adheres to the EN ISO/IEC 17043:2010 standard. It involved three national laboratories (LAT), two of which with an accredited measurement system and the third with an unaccredited measurement system

Evaluation of Fresh Groundwater Lens Volume and Its Possible Use in Nauru Island

A proper management of fresh groundwater lenses in small islands is required in order to avoid or at least limit uncontrolled saltwater intrusion and guarantee the availability of the resource even during drought occurrences. An accurate estimation of the freshwater volume stored in the subsoil is a key step in the water management decision process. This study focused on understanding the hydrogeological system behaviour and on assessing the sustainable use of the groundwater resource in Nauru Atoll Island (Pacific Ocean). A first phase, concerning the hydrogeological characterization of the island, highlighted the occurrence of few drought-resilient freshwater lenses along the seashore. The second part of the study focused on the characterization of a freshwater lens found in the northern coastal area and identified such area as the most suitable for the development of groundwater infrastructures for water withdrawal. The characterization activities allowed quantifying the freshwater lens thickness and volume in order to assess the capability to satisfy the population water demand. A geo-electrical tomography survey was carried out, and a 3D density-dependent numerical model was implemented in SEAWAT. The model results demonstrated that in small islands freshwater can unexpectedly accumulate underground right along the seashore and not in the centre of the island as is commonly believed. Furthermore, the model can constitute a useful tool to manage the groundwater resources and would allow the design of sustainable groundwater exploitation systems, avoiding saltwater intrusion worsening

Hierarchical progressive surveys. Multi-resolution HEALPix data structures for astronomical images, catalogues, and 3-dimensional data cubes

Scientific exploitation of the ever increasing volumes of astronomical data requires efficient and practical methods for data access, visualisation, and analysis. Hierarchical sky tessellation techniques enable a multi-resolution approach to organising data on angular scales from the full sky down to the individual image pixels. Aims. We aim to show that the Hierarchical progressive survey (HiPS) scheme for describing astronomical images, source catalogues, and three-dimensional data cubes is a practical solution to managing large volumes of heterogeneous data and that it enables a new level of scientific interoperability across large collections of data of these different data types. Methods. HiPS uses the HEALPix tessellation of the sphere to define a hierarchical tile and pixel structure to describe and organise astronomical data. HiPS is designed to conserve the scientific properties of the data alongside both visualisation considerations and emphasis on the ease of implementation. We describe the development of HiPS to manage a large number of diverse image surveys, as well as the extension of hierarchical image systems to cube and catalogue data. We demonstrate the interoperability of HiPS and Multi-Order Coverage (MOC) maps and highlight the HiPS mechanism to provide links to the original data. Results. Hierarchical progressive surveys have been generated by various data centres and groups for ~200 data collections including many wide area sky surveys, and archives of pointed observations. These can be accessed and visualised in Aladin, Aladin Lite, and other applications. HiPS provides a basis for further innovations in the use of hierarchical data structures to facilitate the description and statistical analysis of large astronomical data sets.Comment: 21 pages, 6 figures. Accepted for publication in Astronomy & Astrophysic

International standards for fetal brain structures based on serial ultrasound measurements from the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project.

OBJECTIVE: To create prescriptive growth standards for five fetal brain structures, measured by ultrasound, from healthy, well-nourished women, at low risk of impaired fetal growth and poor perinatal outcomes, taking part in the Fetal Growth Longitudinal Study (FGLS) of the INTERGROWTH-21st Project. METHODS: This was a complementary analysis of a large, population-based, multicentre, longitudinal study. We measured, in planes reconstructed from 3-dimensional (3D) ultrasound volumes of the fetal head at different time points in pregnancy, the size of the parieto-occipital fissure (POF), Sylvian fissure (SF), anterior horn of the lateral ventricle (AV), atrium of the posterior ventricle (PV) and cisterna magna (CM). The sample analysed was randomly selected from the overall FGLS population, ensuring an equal distribution amongst the eight diverse participating sites and of 3D ultrasound volumes across pregnancy (range: 15 - 36 weeks' gestation). Fractional polynomials were used to the construct standards. Growth and development of the infants were assessed at 1 and 2 years of age to confirm their adequacy for constructing international standards. RESULTS: From the entire FGLS cohort of 4321 women, 451 (10.4%) were randomly selected. After exclusions, 3D ultrasound volumes from 442 fetuses born without congenital malformations were used to create the charts. The fetal brain structures of interest were identified in 90% of cases. All structures showed increasing size with gestation and increasing variability for the POF, SF, PV and CM. The 3rd , 5th , 50th , 95th and 97th smoothed centile are presented. The 5th centile of POF and SF were 2.8 and 4.3 at 22 weeks and 4.2 and 9.4mm at 32 weeks respectively. The 95th centile of PV and CM were 8.5 and 7.4 at 22 weeks and 8.5 and 9.4mm at 32 weeks respectively. CONCLUSIONS: We have produced prescriptive size standards for fetal brain structures based on prospectively enrolled pregnancies at low risk of abnormal outcomes. We recommend these as international standards for the assessment of measurements obtained by ultrasound from fetal brain structures

Superconducting Qubit Network as a Single Microwave Photon Detector for Galactic Axion Search

Experimental search of galactic axions requires detection of single photons in the microwave range. We work on a novel approach to detect single microwave photons based on a coherent collective response of quantum states occurring in a superconducting qubit network (SQN) embedded in a low-dissipative superconducting resonator. We propose a two resonators detector configuration with two parallel resonators without common part and with separated input and output terminals. The device consists of a low-dissipative resonator with embedded SQN in which microwave photons arrive (“signal resonator”), and a transmission line for measuring the frequency dependent transmission coefficient demonstrating resonant drops at the qubit frequencies (“readout resonator”). In comparison with T-type three terminal device recently proposed and investigated by us, the device with two resonators with separated input and output terminals doesn’t contain common part of both resonators and exclude an unwanted noise from measurement readout circuits to the signal resonator. A layout of two resonators four terminal SQN detectors containing 5 flux qubits weakly coupled to a low-dissipative signal and readout resonator was developed and optimized. The samples were fabricated by Manhattan Al-based technology with Nb resonator circuits. The SQN detector was experimentally tested in terms of microwave measurements of scattering parameters of both resonators and crosstalk properties. Comparison of experimental data with results of the simulations permits one to conclude that the electromagnetic conditions of the fundamental resonant peak of 8.5 GHz of both resonators aren’t affected by the crosstalk phenomenon and their performances provided by the design remain not altered for correct device operation