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This article presents the new theoretical concept of environing media, which is developed to offer critical insight into how processes of mediation affect how we perceive of, manage and use the environment. Building on the insight that the environment has been in a continuous slow process of change that is now escalating due to human impacts, the article sketches a history of how environmental change and mediation are intertwined. Taking the history of agriculture as a case for the theoretical development, it shows how the current digitization of farming and implementation of AI systems in precision agriculture is the last of a long series in which environmental mediation come to play a crucial role in the forging of human–Earth relations. The article thereby shows the complex interplay between knowing and changing the environment as media technologies produce new epistemologies that in turn produce new interventions. QC 20221227

In this paper, we show how Behavior Trees that have performance guarantees, in terms of safety and goal convergence, can be extended with components that were designed using machine learning, without destroying those performance guarantees. Machine learning approaches such as reinforcement learning or learning from demonstration can be very appealing to AI designers that want efficient and realistic behaviors in their agents. However, those algorithms seldom provide guarantees for solving the given task in all different situations while keeping the agent safe. Instead, such guarantees are often easier to find for manually designed model-based approaches. In this paper we exploit the modularity of behavior trees to extend a given design with an efficient, but possibly unreliable, machine learning component in a way that preserves the guarantees. The approach is illustrated with an inverted pendulum example. Accepted as Regular Paper to The 61th IEEE Conference on Decision and Control (CDC 2022)

AbstractMagnetopolymers are of interest in smart material applications; however, changing their magnetic properties post synthesis is complicated. In this study, we introduce easily programmable polymer magnetic composites comprising 2D lattices of droplets of solid-liquid phase change material, with each droplet containing a single magnetic dipole particle. These composites are ferromagnetic with a Curie temperature defined by the rotational freedom of the particles above the droplet melting point. We demonstrate magnetopolymers combining high remanence characteristics with Curie temperatures below the composite degradation temperature. We easily reprogram the material between four states: (1) a superparamagnetic state above the melting point which, in the absence of an external magnetic field, spontaneously collapses to; (2) an artificial spin ice state, which after cooling forms either; (3) a spin glass state with low bulk remanence, or; (4) a ferromagnetic state with high bulk remanence when cooled in the presence of an external magnetic field. We observe the spontaneous emergence of 2D magnetic vortices in the spin ice and elucidate the correlation of these vortex structures with the external bulk remanence. We also demonstrate the easy programming of magnetically latching structures.

Kilamba, the first of the new centralities in Angola, is increasingly visible in recent urban scholarship about Luanda, further establishing it as the symbol of both this “new” post-war city and the “New Angola.” Within local discourses of progress, its emergence from within “petro-urbanism,” and its size and modern aesthetics are emphasized, while little attention has been directed towards understanding the actual contributions of its workers, particularly the women who spend a significant part of their day cleaning Kilamba’s apartments. In this paper, we combine a social reproduction framework with infrastructure studies to trace the labor of Kilamba’s female domestic workers, in order to demonstrate how their everyday practices uphold the status and materiality of this centrality, even as their work is invisibilized. In doing so, we understand their commentaries about this space, often refracted through descriptions of their homes, as critiques of the infrastructural priorities of the “New Angola.” QC 20230227 Grounding and Worlding Urban Infrastructure (GROWL)

Abstract Fibre-reinforced shotcrete is the most common support method for hard rock tunnels in the Nordic countries. The design of shotcrete is often based on empirical methods or simplified analytical equations, which neglect variations in mechanical properties and shotcrete thickness. Data collected from the field shows that significant variations in shotcrete thickness and bond strength should be expected during tunnel construction. However, how this affects the structural behaviour and capacity of the shotcrete lining is unknown. Moreover, the design philosophy for shotcrete assumes that the primary failure modes of shotcrete, i.e. bond and flexural failure, can be treated separately. This was derived based on observations of experiments in a laboratory environment. Therefore, the focus of a finalized doctoral project was to develop a numerical framework to simulate the structural behaviour of fibre-reinforced shotcrete in interaction with hard rock and rock bolts. The effect of variations in shotcrete thickness and bond strength was studied through numerical simulations to increase the understanding of its effect on the failure load of the lining. The results indicate that the most important parameter is the mean value of the shotcrete thickness and bond strength around a narrow perimeter of the block.’

Many works in capacitive deionization (CDI) use finite-element (FEM) simulations to investigate process behavior. Here, we present ELC, comprehensive software that integrates these methods with COMSOL Multiphysics. It can save significant time for common research questions in CDI operations and is well-suited for new research questions in complex and upscaled device designs. The ELC software has already been used for the simulation of time-varying desalination output, charge leakages, bipolar electrode devices, and stacks of over 100 CDI cells. Finally, we provide a video tutorial on how to use the software. In conclusion, ELC could be a strong software for aiding current and future research in electrochemical desalination. QC 20221123

An increasing body of literature on sustainability transitions addresses the business strategies of incumbents but overlooks upstream companies. By addressing this gap, we aim to explore how upstream incumbents navigate sustainability transitions. Theoretically, we introduce an industry value chain perspective, integrating the concepts of center of gravity, patterns of strategic change and organizational adaptation. Empirically, we conduct an in-depth case study of how an up- stream incumbent firm navigates the established value chain for lead-acid batteries and the emerging value chain for lithium-ion batteries used in electric vehicles. The company faces a dilemma as to whether and how to maintain a vertically integrated position in the established value chain, and how and when to expand into the emerging value chain. We argue and demonstrate that for upstream companies, navigating sustainability transitions is highly dependent on the anticipation of and adaptation to the complex changes in industry value chains. QC 20230124

As cities worldwide implement strategies to accelerate the transition toward a circular economy (CE), there is an increasing need for tools to monitor progress. However, a standardised metric for CE monitoring in urban areas is lacking. This study examines the potential of the EU Circular Economy Monitoring Framework (CEMF), an established indicator-based framework for measuring national- and EU-level circularity performance, as a monitoring tool for urban areas. For this purpose, available data sources that can support the framework's application at the urban level are mapped, and data quality is assessed following the pedigree matrix approach. Next, the CEMF indicators are computed for the urban area of Umeå, Sweden. The mapping showed limited availability of urban-level data, necessitating the downscaling of national-level data using proxy factors. Most available urban-level data are of high quality, while the quality of national-level data is reduced when used to compute indicators at the urban level. The application of the CEMF in Umeå indicates that there are areas where the municipality performs well, though further improvements are needed. We conclude that the CEMF has potential as a monitoring tool for urban areas. However, improvements in CEMF...s scope and data availability are recommended. QC 20221205

Publisher Copyright: © 2022 The Authors Tungsten is considered to be used in the future fusion reactors as plasma-facing material. In such ex-treme environments, defects are induced in materials that modify their macroscopic properties such as the mechanical ones. It is of paramount importance to be able to determine concentration and size of the vacancy defects, from the mono vacancy to the large cavities, to validate the models developed to predict the evolution of the microstructure of irradiated materials. Positrons are very useful non-destructive probes that can characterize vacancy-type defects in materials. We present a combined ex-perimental and theoretical study on detecting and estimating the sizes of vacancy clusters that are invis-ible with electron microscopy in tungsten, using positron annihilation spectroscopy. We here model the positron annihilation in the tungsten lattice and in vacancy-type defects using state-of-the-art first prin-ciples methodology. The Doppler broadening spectra and positron lifetimes in tungsten are calculated with two-component density functional theory with local density approximation and weighted density approximation. Our calculations are in excellent agreement with our experimental results. We show that the sizes of vacancy clusters in tungsten can be well estimated by combining both positron lifetimes and Doppler broadening spectra. We also determine the limit of validity of the canonical calculation method, which here is shown to fail when the vacancy clusters grow beyond their nucleation stage. This work is a first step needed to better interpret the measured positron annihilation characteristics (Doppler and lifetime) in tungsten and then extract quantitative data on small vacancy defects required to improve the understanding of early-stage vacancy defect evolution in tungsten. The method used in this paper could be used to study other metallic materials.(c) 2022 The Authors. Published by Elsevier B.V.This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ ) Peer reviewed

International audience; In this work, the Cu clustering in Fe under irradiation is investigated using experiments, cluster dynamics and atomistic kinetic Monte Carlo (AKMC) simulations. In experiments, cast iron and model FeCu alloy samples were irradiated with 2 MeV electrons for 143 h at 140 °C. The post-irradiation microstructure was characterized using atom probe tomography. Cluster dynamics and AKMC methods were used to simulate the Cu clustering under the same irradiation conditions. Both simulation methods show satisfactory agreement with experiments, lending strength to the validity of the models. Finally, the Cu clustering in spent-fuel repository conditions for 10$^5$ years at 100 °C was simulated using both methods. The results indicate that potential hardening by Cu clustering is insignificant over 10$^5$ years.