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Multi-layer frequency selective surface wideband filter with high selectivity operating in L, S, and C bands
No full textThis paper presents the design and analysis of a novel 2D multilayer frequency selective surface (FSS) passband filter conceived for broadband response with pronounced roll-off characteristics. Unlike conventional 2D structures, the proposed multi-layer architecture improves bandwidth and filter selectivity while preserving an easy manufacturing process. The design is carried out by adopting a layer-by-layer equivalent circuit extraction technique that allows accurate impedance tailoring in order to accomplish the desired behavior in the L, S and C bands. The complete structure is composed by 3 stacked FSS layers, opportunely separated by foam gaps, achieving a compact 67 mm overall thickness. The performance predicted by the analytical modelling was also confirmed through full-wave simulations and experimental measurements, highlighting an excellent agreement. The proposed filter achieves an extensive − 3 dB passband from 2.79 GHz to 6.65 GHz, reaching 90% of fractional bandwidth, with sharp roll-offs of 42 dB/GHz and 70 dB/GHz. Thus, the − 10 dB rejection bands cover the 1.2 –2.62 GHz and the 6.75 –7.9 GHz ranges, accomplishing a full operation coverage of L, S and C bands. Finally, the filter’s lightweight and affordable design makes it particularly suitable for modern communication systems that require effective out-of-band attenuation with elevated selectivity and compact integration
Rack supported warehouses with reduced-section diagonals for improved dissipative seismic behaviour
No full textRack supported warehouses are structures proven to be vulnerable to seismic action as currently designed, being prone to quasi-brittle failures that mainly involve key components. This paper presents a dedicated design approach for the transversal frames of these warehouses, with the main objective of exploiting potential sources of ductility (yielding of diagonals under tensile force) while protecting the non-dissipative components and maintaining the structural configuration and technological components typical of these structures. To this end, the diagonal's cross-section is reduced in specific areas, allowing for yielding and seismic dissipation, while ensuring the overstrength of the connection. Specific guidelines are also provided to design the reduced section portions to achieve the necessary ductility level, both locally and globally, and to limit the slenderness of the profile. The potential of the approach is evaluated by designing and numerically assessing the seismic vulnerability of a case study and comparing the obtained behaviour to that of the same structure designed using the current approach. The results show that the new approach allows for the protection of diagonal connections and non-dissipative elements for seismic intensities higher than the design level. An experimental campaign on the reduced-section braces is an ongoing activity necessary to assess the effective behaviour and to provide general design criteria that also account for geometrical and material imperfections arising from fabrication and assembly processes
Online Curvature-Aware Replay: Leveraging 2nd Order Information for Online Continual Learning
No full textOnline Continual Learning (OCL) models continuously adapt to nonstationary data streams, usually without task information. These settings are complex and many traditional CL methods fail, while online methods (mainly replay-based) suffer from instabilities after the task shift. To address this issue, we formalize replay-based OCL as a second-order online joint optimization with explicit KL-divergence constraints on replay data. We propose Online Curvature-Aware Replay (OCAR) to solve the problem: a method that leverages second-order information of the loss using a K-FAC approximation of the Fisher Information Matrix (FIM) to precondition the gradient. The FIM acts as a stabilizer to prevent forgetting while also accelerating the optimization in non-interfering directions. We show how to adapt the estimation of the FIM to a continual setting, stabilizing second-order optimization for non-iid data, uncovering the role of the Tikhonov damping in the stability-plasticity tradeoff. Empirical results show that OCAR outperforms state-of-the-art methods in continual metrics, achieving higher average accuracy throughout the training process in three different benchmarks
Fission Product Release Modeling in MELCOR: an Extension of the Validation
No full textSevere Accident (SA) integral codes, such as MELCOR, are widely employed to analyze accidental scenarios and evaluate source term. To ensure consistency and reliability, physical models within codes must be validated against experimental data.
Therefore, this paper describes the MELCOR 2.2 modelling of two small-scale Fission Product Release (FPR) experiments. A generic approach has been developed to simulate the VEGA [1] and HEVA [2] programs. Two MELCOR’s release models, namely Revised CORSOR-Booth (RCB), the default in MELCOR, and ORNL-Booth (OB), the latest version proposed by developers [3], are employed. The focus is put on Cesium (Cs) releases, as MELCOR evaluates the release of any radionuclides relative to Cs
Pupillary Hippus as a Biomarker: Spectral Signatures and Complexity Approaches in Autonomic and Clinical Contexts
No full textExciton Delocalization Promotes Far-Red Absorption in a Tetrameric Chlorophyll a Light-Harvesting Complex from Trachydiscus minutus
No full text: Photosynthetic organisms employ light-harvesting complexes (LHCs) to optimize energy capture under variable light conditions. The freshwater eustigmatophyte Trachydiscus minutus accumulates a red-shifted violaxanthin-chlorophyll protein (rVCP) that contributes to far-red light harvesting using only chlorophyll (Chl) a molecules, without chemical modification or substitution of pigments. Based on high-resolution cryo-EM and multiscale quantum chemical calculations, we uncovered a heterodimer-based tetrameric architecture, representing a unique oligomerization mode among LHCs. Within each heterodimer, Chls a are distinctively arranged adjacent to the terminal emitter, forming an unprecedentedly extended chlorophyll cluster. Quantum chemical calculations reveal three strong exciton-coupled pigment domains, two of which reside in the large cluster and solely account for the intense far-red absorption near 700 nm without contributions from charge-transfer states. Our structural and quantum chemical characterizations of far-red light harvesting reveal a molecular mechanism of red spectral tuning that relies on protein-controlled excitonic coupling of identical Chl a pigments, as demonstrated here in this eustigmatophyte, highlighting diverse adaptations for harvesting spectrally shifted, low-energy light
Characterisation of a 20 kW Dual Channel HT with Different Propellants (Xe/Kr/Ar)
No full textA 20 kW class Hall Thruster featuring two coaxial channels has been designed at the University of Pisa and manufactured by Aerospazio Tecnologie. The thruster was preliminarily characterized in 2024 in the framework of the ESA TANDEM program. The following paper outlines the findings from the recent characterization test campaign performed on the TANDEM thruster coupled with the new cathode developed within the CHEOPS-VHP-BB program. This test was carried out at AEROSPAZIO Tecnologie in 2025 in the LVTF-3 test facility. The TANDEM thruster was operated with three different propellants (Xenon, Krypton, and Argon) in four operating points (from 4.5 to 20 kW) at discharge voltages of 300 and 400 V. Thermal assessments were performed using an infrared thermal camera. This document presents the experimental results collected throughout the testin
Commentary: Guselkumab binding to CD64+ IL-23–producing myeloid cells enhances potency for neutralizing IL-23 signaling
No full textCommento a:
R. Meral, N. Malandrino, M. Walter, A.H. Neidert, R. Muniyappa, E.A. Oral, R.J. Brown, Endogenous leptin concentrations poorly predict metreleptin response in patients with partial lipodystrophy, in FRONTIERS IN IMMUNOLOGY 16 (2025) 1532852, DOI: 10.3389/fimmu.2025.1532852
J Clin Endocrinol Metab (2021) 22:dgab76