Abstract

Abstract
Radon (Rn-222) is a unique atmospheric tracer, since it is an inert gaseous radionuclide with a predominantly terrestrial source and a short half-life (3.8232 (8) d), enabling quantification of the relative degree of recent (< 21 d) terrestrial influences on marine air masses. High quality measurements of atmospheric radon activity concentration in remote oceanic locations enable the most accurate identification of baseline conditions. Observations of GHGs under baseline conditions, representative of hemispheric background values, are essential to characterise long-term changes in hemispheric-mean GHG concentrations, differentiate between natural and anthropogenic GHG sources, and improve understanding of the global carbon budget.The EU-funded project NuClim (Nuclear observations to improve Climate research and GHG emission estimates) will establish world-leading high-quality atmospheric measurements of radon activity concentration and of selected GHG concentrations (CO2, and CH4) at a remote oceanic location, the Eastern North Atlantic (ENA) facility, managed by the Atmospheric Radiation Measurement (ARM) programme (Office of Science from the U.S. Department of Energy), located on Graciosa Island (Azores archipelago), near the middle of the north Atlantic Ocean. These observations will provide an accurate, time-varying atmospheric baseline reference for European greenhouse gas (GHG) levels, enabling a clearer distinction between anthropogenic emissions and slowly changing background levels. NuClim will also enhance measurement of atmospheric radon activity concentration at the Mace Head Station, allowing the identification of latitudinal gradients in baseline atmospheric composition, and supporting the evaluation of the performance of GHG mitigation measures for countries in the northern hemisphere.The high-quality nuclear and GHG observations from NuClim, and the resulting classification of terrestrial influences on marine air masses, will assist diverse climate and environmental studies, including the study of pollution events, characterisation of marine boundary layer clouds and aerosols, and exploration of the impact of natural planktonic communities on GHG emissions. This poster presents an overview of NuClim, outlines the project objectives and methodologies, and summarises the relevant data products that will be made available to the climate community.Project NuClim received funding from the EURATOM research and training program 2023-2025 under Grant Agreement No 101166515.

Abstract
Caves and lava tubes offer ideal environments for testing and improving methodological approaches as natural space analogs and living laboratories. These underground environments hold natural records that help us understand the evolution of our planet. This research reflects on the relevance of lava tubes and caves as simulation sites for extraterrestrial exploration. This study will focus on the methodological approach used in Lanzarote (Canary Islands, Spain) and Selvagens Islands (Madeira, Portugal), as two space analog sites associated with astrobiology projects that demonstrated good practice and reliable science and can inspire other space-related programs. Finally, the lava tube system on Terceira Island (Azores) is presented for the first time in Portugal as a promising new experimental site for geoengineering research and space analog activities. The multisectoral and longitudinal investigations related to a geoengineering approach and the 5Gs project will leverage the unique geodiversity and biodiversity of Natal Cave. Lava tube habitats could ultimately enable the establishment of a sustainable human presence on the Moon or Mars. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

Abstract
Li-ion batteries are widely used in electric vehicles, grid storage, and portable electronics. Battery Management Systems play a crucial role in ensuring the safety, efficiency, and longevity of Li-ion batteries. Accurate battery modelling is essential for effective battery management functionality, enabling precise state of charge/ state of health estimation, as well as protection against hazardous conditions such as overcharging or overheating. This article explores system identification techniques for battery modelling using a piecewise LTI approach where separate LTI models are identified for different state of charge intervals. A modified Thevenin circuit is employed, where the open-circuit voltage is represented by a capacitor that models the bulk charge storage. The capacitance of this element is dependent on the state of charge, reflecting the nonlinear nature of the battery's charge storage mechanism. Additionally, parallel resistor-capacitor networks capture transient voltage recovery dynamics. The identification process estimates the battery parameters from experimental data, and the resulting piecewise models are interpolated using cubic splines to construct a linear parameter-varying (LPV) representation of the system. The proposed methodology was validated through experimental results, demonstrating its effectiveness in enhancing battery management performance. Namely, (i) the model accurately captures the battery's voltage response with minimal error. (ii) the LPV model obtained by fitting splines to the estimated parameters demonstrates a level of accuracy comparable to that of the piecewise LTI model. (iii) the model robustness was validated through a continuous discharge test, showing strong agreement with experimental data and, therefore, demonstrating its reliability in real-world operating conditions. These results highlight the potential of the proposed methodology in improving battery management systems. Copyright (c) 2025 The Authors. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract
Estuaries are dynamic ecosystems where freshwater and seawater interact, shaping complex hydrodynamic and environmental processes. Traditional single-node monitoring systems, while informative, lack the spatial resolution necessary to fully capture these dynamics. This study presents the development and deployment of a dual-node synchronized wireless sensor network for real-time environmental monitoring in the Cavado Estuary, Portugal. The network architecture integrates low-power embedded systems, a synchronized radiofrequency network, and a web-based data visualization platform. Two monitoring nodes, deployed 675 meters apart, operate in a synchronous cycle to measure hydrostatic pressure and water temperature, demonstrating the feasibility of synchronized environmental sensing. The collected data validated network synchronization, revealing a 30-minute delay in tidal propagation between nodes and highlighting temperature variations influenced by estuarine hydrodynamics. Additionally, long-term observations captured seasonal trends, tidal influences, and extreme weather events such as Storm Kirk. The study also evaluated the system's energy efficiency, confirming the solar panel's capacity to sustain continuous operation and estimating battery life expectancy under different network configurations. This work advances synchronized monitoring networks by providing a scalable, low-cost solution for studying marine environments. The proposed system enables more precise quantification of oceanic influences on estuarine conditions, particularly regarding tidal propagation and phase differences, supporting more effective ecosystem management and understanding.

Abstract
This study presents the development and testing of satellite antennas for the SONDA probe, an innovative deepsea monitoring system designed to be deployed by high-altitude balloons. The probe descends to the deep ocean, resurfaces, and transmits data while functioning as a drifter. The project faced unique design constraints, including the need for low-cost materials and lightweight construction for balloon deployment. These constraints ruled out traditional hermetic housings, necessitating alternative solutions for antenna protection. The work focused on custom ceramic patch antennas and their performance under various protective coatings, which affected the antennas' resonance and gain. Thinner layers effectively protected the antennas from high-pressure conditions and water ingress, maintaining functionality. Experiments on antenna height revealed optimal positioning above the water surface to minimize wave-induced signal interference. Hyperbaric chamber tests validated the mechanical integrity and functionality of the antennas under pressures equivalent to depths of 1500 m Antenna characterization techniques were employed in an anechoic chamber to validate antenna performance with the coating and to assess their correct operation after the hyperbaric tests. Field deployments demonstrated the antennas' capability to transmit data after diving. Challenges included communication delays, corrupted data, and mechanical vulnerabilities in materials. The findings emphasize the importance of rigorous mechanical design, material selection, and system optimization to ensure reliability in marine environments. This work advances the development of low-cost, lightweight, and modular probes for autonomous ocean monitoring, with potential applications in long-term drifter studies, real-time marine monitoring and oceanographic research.