Oskar Bordeaux
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New Wideband Large Aperture Open-Ended Coaxial Microwave Probe for Soil Dielectric Characterization
No full textWe present a unique open-ended coaxial probe (OECP) that can accurately measure the permittivity of heterogeneous materials due to its large aperture. The probe works at frequencies ranging from 0.5 to 18 GHz, which is an important range for microwave remote sensing applications, and more precisely the Terrestrial Snow Mass Mission (TSMM). TSMM aims at launching a new satellite equipped with a dual Ku-band radar (13.5 and 17.2 GHz) for snow monitoring. At Ku-band frequencies, the backscattered radar signal contains information not only about the snow but also about the soil underneath. Knowing the soil permittivity will allow models to better account for the soil contribution to the total signal and to obtain more accurate snow data. To demonstrate the accuracy of the probe and the repeatability of the measures, calibration solutions of known permittivity were measured, and the results were compared to their theoretical values. Then, we conducted tests for approximating the penetration depth of the probe signal with dry and wet papers. Afterward, a protocol to use the probe to compute the permittivity of soil samples in freeze/thaw cycles was developed. The permittivities of commercial sand and organic soil from Iqaluktuuttiaq (Cambridge Bay, Nunavut, Canada) are presented for different relevant frequencies for microwave remote sensing applications and different temperatures (−20 °C to 20 °C) according to the new protocol. This article aims to present the probe and its potential use in microwave remote sensing applications, especially for the active Ku-band, where little research exists
From the Mine to the Forge : Iron Exploitation across the Eretrian Territory
No full textL’exploitation du fer dans le territoire de la cité antique d’Érétrie demeure peu étudiée, en dépit de la richesse en gisements ferrugineux de la région. La chaîne opératoire de la métallurgie du fer antique — depuis l’extraction du minerai jusqu’à la forge — n’a, à ce jour, jamais fait l’objet d’une étude intégrée. Cependant, les récents développements de la recherche à l’échelle régionale, et le changement d’échelle qu’ils impliquent, rendent désormais possible une approche globale du système de production, replacé dans le cadre plus large de l’exploitation des ressources et de la gestion du territoire érétrien.Entre 2023 et 2025, trois campagnes de terrain ont été menées. La première consistait en un inventaire exhaustif des vestiges liés au travail du fer mis au jour lors des fouilles de l’École suisse d’archéologie en Grèce et conservés au Musée archéologique d’Érétrie. Ce travail a permis d’enregistrer plus de 1 650 artefacts — scories, chutes métalliques, fragments de parois de foyer et échantillons de minerai — selon un protocole systématique relevant de l’archéométallurgie. Cet inventaire a également permis d’identifier plusieurs catégories technologiques et de proposer une typologie préliminaire des activités de production attestées dans l’espace urbain.Dans le prolongement de cette étude, deux campagnes de prospection thématique ont été réalisées en 2024 et 2025 dans le cadre de l’Eretria and Amarynthos Survey Project (EASP – ESAG), afin d’élargir le champ de l’enquête. Axées sur la recherche d’indices d’activités sidérurgiques, ces prospections ont permis d’identifier des traces correspondant à plusieurs étapes du processus de production, jusque-là absentes des contextes urbains. Bien que parfois ténus — notamment en raison des perturbations liées aux pratiques agricoles modernes — ces indices témoignent, à l’échelle du territoire, d’une organisation structurée de l’extraction du minerai et de la production du fer dans la chôra érétrienne.La mise en relation des données issues des contextes urbains et ruraux renouvelle ainsi la compréhension de l’organisation de la production. Si les premiers semblent avoir accueilli des ateliers de forge, les seconds paraissent dédiés à l’extraction et à la réduction primaire. Cette complémentarité fonctionnelle suggère l’existence d’un système intégré reliant l’approvisionnement en matière première, les choix techniques et la distribution des produits finis. Par l’analyse croisée de ces différents ensembles de données, cette recherche vise à reconstituer la chaîne opératoire complète de la métallurgie du fer à Érétrie, « de la mine à la forge ».The exploitation of iron within the territory of the ancient city of Eretria remains understudied, despite the region’s wealth of ferruginous deposits. The chaîne opératoire of ancient ironworking – from ore extraction to forging – has, to date, never been the subject of a fully integrated study. However, recent developments in research conducted at a regional scale, and the shift in perspective they entail, now make it possible to adopt a comprehensive approach to the production system, placing it within the broader context of resource exploitation and landscape management in the Eretrian territory.Between 2023 and 2025, three field campaigns were conducted. The first consisted of an exhaustive inventory of iron-related remains uncovered during the excavations of the Swiss School of Archaeology in Greece and preserved in the Archaeological Museum of Eretria. This work recorded over 1,650 artifacts, including slags, metal scraps, furnace-wall fragments, and ore samples. Conducted within an archaeometallurgical framework, this systematic inventory also enabled the identification of several technological categories and provided a preliminary typology of production activities documented within the urban area.Following this study, two thematic field surveys were carried out in 2024 and 2025 as part of the Eretria and Amarynthos Survey Project (EASP – ESAG), aiming to broaden the scope of the investigation. Focusing on evidence for ironworking, these surveys identified traces corresponding to several stages of the production process that were previously absent from urban contexts. Although these indicators are sometimes subtle – particularly due to disturbances caused by modern agricultural practices – their presence across the territory strongly suggests a structured organization of ore exploitation and iron production within the Eretrian chora.The integration of data from urban contexts with that from rural sites sheds new light on the organization of production. While the former appear to have hosted forging workshops, the latter seem likely to have been dedicated to extraction and primary smelting. This functional complementarity points to the existence of an integrated system connecting raw-material procurement, technological choices, and the distribution of finished products. Through the combined analysis of these various datasets, this research aims to reconstruct the complete chaîne opératoire of ironworking in Eretria – from the mine to the forge
The Circular Value Navigator: A Tool for Identifying and Transforming Linear Practices in the Circular Economy
No full textThe transition to a circular economy (CE) presents a significant challenge for firms, especially
in the initial stages, where cognitive barriers can hinder the identification of linear
practices and the development of circular solutions. One key approach to supporting
business model innovation has been the use of visualization tools. While several tools
facilitate circular innovation, most remain primarily descriptive or evaluative and do not
bridge the gap between diagnosing linear practices and designing circular value propositions.
This paper addresses this gap by introducing a conceptual tool—the ‘Circular
Value Navigator’—designed to support managers in the early stages of CE transformation.
The tool aims to facilitate a systemic process for identifying problems rooted in the dominant
linear economy and converting them into actionable CE opportunities. Therefore,
it supports the development of circular value propositions. The proposed tool integrates
three core dimensions: Value Uncaptured, Innovation Perspectives, and Circularity Strategies.
By systematically exploring the interplay among these dimensions, the tool helps
users identify and map circularity hotspots and pathways for improvement. This research
contributes to the literature on cognitive tools in the circular economy field by offering
a framework that enhances managers’ abilities in systemic thinking, problem reframing,
and the strategic design of circular business models—ultimately aiming to accelerate the
adoption of sustainable practices
Environmental regulation and foreign direct investments: evidence from a new measure of environmental stringency
No full textAbstract
This paper investigates the impact of environmental regulations on inward foreign direct investment (FDI) using a novel index that distinguishes between the implementation and enforcement of environmental policy across 111 countries from 2001 to 2018. Leveraging bilateral FDI data and a structural gravity model, we find robust evidence of a Pollution Haven Effect: weaker environmental regulations in host countries are associated with higher levels of inward FDI. The effect is more pronounced in emerging markets and in environments with higher corruption. Importantly, we show that FDI responds more strongly to policy implementation, capturing formal regulatory commitment, than to enforcement, measured as deviations between predicted and actual emissions. In addition, bilateral FDI patterns are shaped by the environmental stringency gap between source and host countries, consistent with regulatory arbitrage behavior
A robust trajectory tracking controller for constrained and perturbed unicycle mobile robots
No full textAbstract
This paper contributes to the design of a robust control strategy for the trajectory tracking problem in constrained and perturbed unicycle mobile robots. The proposed robust control strategy is composed of two controllers: a linear and a nonlinear. The linear control design is based on the barrier Lyapunov function and the attractive ellipsoid method, and it considers the input saturation, the state constraints, and some parameter uncertainties. On the other hand, the nonlinear part is based on an integral sliding‐mode control approach that deals with the effect of some matched disturbances and the input saturation constraints. The proposed scheme guarantees asymptotic convergence to zero of the tracking error coping with the system constraints and disturbances. Simulation results are presented in order to show the advantage of the proposed algorithm with respect to an MPC‐based robust controller. Some experimental results, using the QBot2 unicycle mobile robot, validate the effectiveness of the proposed robust control strategy
