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The succession of crises in the French professional fishing sector raises the question of the sector's capacity to adapt to changes in its global environment, and of the possibilities for fishermen to change their practices. Through interviews with fishermen and representatives, 5 ideal types of individual transitions were described, as well as two examples of changes in the fisheries management system. Some changes can be characterised as adaptations following a shock, rather than real voluntary and planned transitions. Voluntary individual transitions do exist, however, initiated by a variable trigger factor, but they require a high degree of introspection about personal and professional expectations. These examples of transitions are made possible by the rare synchronisation of external events and various characteristics of the project owners and remain overall a niche phenomenon in the current situation. There is little scope for transition in the sector, mainly because of the difficulty of accessing production rights and the rigidity of management systems. To help the sector evolve and adapt to a changing macro-environment (organisational, environmental, societal, energy, etc.), transition levers can be mobilised at organisational, political, financial, technical, social and societal levels. The age structure of ships and people will probably be the mainstay of a major reconfiguration of the sector in the short term.

This paper addresses the role of policy in driving technology change to reduce maritime transport emissions. While liquefied natural gas (LNG) is little better than fuel oil from a carbon perspective, it emits very low levels of other pollutants Sulphur Oxides (SOx), Nitrogen Oxides (NOx) and Particulate Matter (PM). However, despite a great deal of policy effort, the switch from fuel oil to LNG has not occurred at significant scale. Policy makers are already turning towards other fuels such as hydrogen. This paper explores the failure of policy to support the transition to LNG through the lens of the principal-agent problem, examining the influence of its key challenges at the intersection of three geographical scales (international, supranational and national) in the European Union. The case analysis reveals a lack of incentive alignment between both different levels of public actors (the EU and member states) and between public and private actors, producing a lack of agency and an uncertainpolicy environment, exacerbated by a lack of monitoring and sanctions by the EU of its member states. This research provides a better understanding of the shortcomings of transition policy in the case of LNG which provides lessons on the need for more coherent, comprehensive and stringent policy that could prevent another policy failure in the transition towards other alternative fuels.

In several Pacific Island countries and territories (PICTs), rapid population growth and inadequate management of coastal fish habitats and stocks is causing a gap to emerge between the amount of fish recommended for good nutrition and sustainable harvests from coastal fisheries. The effects of ocean warming and acidification on coral reefs, and the effects of climate change on mangrove and seagrass habitats, are expected to widen this gap. To optimise the contributions of small-scale fisheries to food security in PICTs, adaptations are needed to minimise and fill the gap. Key measures to minimise the gap include community-based approaches to: manage catchment vegetation to reduce sedimentation; maintain the structural complexity of fish habitats; allow landward migration of mangroves as sea level rises; sustain recruitment and production of demersal fish by managing ‘source’ populations; and diversify fishing methods to increase catches of species favoured by climate change. The main adaptions to help fill the gap in fish supply include: transferring some fishing effort from coral reefs to tuna and other large pelagic fish by scaling-up the use of nearshore fish aggregating devices; developing fisheries for small pelagic species; and extending the shelf life of catches by improving post-harvest methods. Modelling the effects of climate change on the distribution of yellowfin tuna, skipjack tuna, wahoo and mahi mahi, indicates that these species are likely to remain abundant enough to implement these adaptations in most PICTs until 2050. We conclude by outlining the policies needed to support the recommended adaptations.

The need of the ecological transition require a major renovation of transportation means with the aim of reducing their environmental impacts. Several solutions are already proposed, such as the vehicles hybridization or electrification right from the manufacturing phase. Retrofitting involves replacing the powertrain of the thermal vehicles with an electrified powertrain, while taking into account a number of details and issues that can influence this transformation.This paper presents the retrofit process and the resulting technical, economic, and regulatory constraints. The initial results of a comparative study on the impact of battery types on the distance traveled are also presented. To achieve this, a dynamic model of the vehicle and the battery was developed. Based on two standard driving cycles (WLTP and HWFET), the initial results showed that the choice of battery and its weight are determining factors for the autonomy of electric vehicles. High energy density batteries (Exemple : NMC), although expensive, offer the best performance in terms of autonomy.

The estimation and increase of the lifetime of PEMFC fuel cell under dynamic conditions is one of a major challenge about PEMFC. Increasing the durability of the fuel cell must be treated by both the development of new material and design but also by optimal strategies and control of the operating conditions of the fuel cell. To validate some new strategies for lifetime and also the durability of new material, experimental tests must be coupled with modeling and numerical simulations. Indeed, the different irreversible degradation mechanisms in the MEA (Membrane Electrode Assembly) (as the platinum dissolution, Ostwald ripening, carbon support corrosion and chemical membrane degradation) and reversible degradation mechanisms (platinum oxidation, liquid water management) are strongly coupled to the local conditions into the MEA. Moreover, the local conditions into the MEA are depending of the material properties and the operating conditions of the fuel cell stack. The strong coupling of the different phenomena and the heterogeneities along the surface of the cell and through the thickness of the MEA can be solved only by numerical simulations. In this talk, to predict the degradation mechanisms along the surface of the cell and function of the dynamic operating conditions, three multi-physics models are linked together (see Figure). The three models are described below. i/ EDMOND model is a 0D double layer model to calculate the local surface potential at the surface of the catalyst as well as the coverage of the various reaction intermediates, based on a dynamic coupling between the local operating conditions and the kinetics of the various reaction steps. Both the surface potential and the coverage are involved in the mechanistic models, which makes the EDMOND framework required for such a modeling approach. ii/ The MEA model is a 2D CFD model cross-section of the MEA. The model is able to compute the differences in operation under the rib and channel of the bipolar plate. It takes into account the gas diffusion, thermal, ionic and electrical transport and electrochemical response based on Butler-Volmer approach. Anisotropy and compression of the materials are also taken account. The catalyst layer is meshed through the thickness. iii/ The fuel cell model (called PS++ code) is a 2D+1D fuel cell model, based on bond graph approach. PS++ is a dynamic multi-physic model taking into account two phases flow and heat transport equations. The model is used to calculate the local conditions along the surface of the cell function of dynamic operating conditions. Degradation mechanisms are added (by bottom-up or top-down approach) to estimate the fuel cell lifetime. The irreversible and reversible degradation mechanism are modeled in the local model and up-scaled into the cell model PS++. The local double layer model (EDMOND) is used to calculate the irreversible degradations of the loss of catalyst (Ostwald ripening). The Ostwald ripening model integrated in EDMOND relies on a multiscale mechanistic approach where parameters come from DFT calculations. It is able to calculate the dependency of both the size and the distribution of the particles, the voltage and the hydration in the degradation rate. The MEA model is used to calculate the reversible degradations. The catalyst oxidations are introduced and are in competition with the electrochemical reactions (ORR and HOR), allowing to compute dynamically the evolution of the active catalyst surface. The upscaling of the degradations and the activity of the catalyst are introduced into the cell model to simulate the loss of performance of the cell under dynamic solicitations and to calculate the effects of local degradations on the repartition of the current density along the surface of the cell. The experimental validation of the approach is realized by two 2000 hours experimental tests in a 30 cells stack. The experimental tests have been carried out in a fuel cell stack durability tests with a permanent current density for the first test and a dynamic solicitation for the second one. Current density measurement card and periodic electrochemical characterizations are realized during the tests and post-mortem characterizations at the end of the tests. The results show a good qualitative agreement with the model simulations, in particular to the current density distribution function of ageing and the reversible and irreversible mechanisms. In conclusion, the approach of lifetime prediction by a full multi-scale approach is demonstrated and open new perspectives about the coupling of modeling and experimental tests to increase the durability of the fuel cell. Figure 1

Abstract In this work, we propose a fully Bayesian uncertainty analysis of the indirect measurement of thermal properties of walls from in situ temperature and flux measurements, obtained with an active method, using a one dimensional transient thermal model. We show that this approach is able to take into account the uncertainty of the inputs of the thermal model and the uncertainty of the output observations, for a more reliable uncertainty estimation of the calibration parameters and any derived quantity. For this problem, we improve the classical Bayesian inversion model by taking into account underestimated uncertainty on reported output observations, which is a frequently encountered issue in practice. We provide some recommendations for a wider applicability of the method. We illustrate the principles of uncertainty evaluation of the Guide to the Expression of Uncertainty in Measurement in terms of a real case study to evaluate the thermal resistance of a multilayer wall placed in a climatic chamber. For this application, we compare results of the Bayesian inversion with classical steady-state results in comparable experimental conditions. We perform a sensitivity analysis to study the effect of duration, input uncertainties and excess variance prior, and we make recommendations. R code is made available that enables a Bayesian uncertainty evaluation of inversion models for related applications.

Menée dans l'entreprise REGA, distributeur-grossiste en boissons pour les Cafés-Hôtels-Restaurants (CHR), cette thèse CIFRE vise à rendre la logistique urbaine d'une PME plus responsable environnementalement en améliorant les conditions de travail de ses collaborateurs tout en étant durable économiquement. L’intégration de la logique de durabilité vient accentuer les paradoxes et les conflits dus à l'hybridité institutionnelle, déclenchant des refus du changement à toutes les échelles et chez toutes les parties prenantes. La recherche est conduite en recherche-intervention, les données utilisées sont mixtes et issues du terrain de recherche. Les résultats devraient permettre de comprendre comment une PME intermédiaire finale d'une chaîne logistique peut améliorer les conditions de travail des chauffeurs-livreurs en impliquant les collaborateurs et les clients dans le processus et en tenant compte de la dépendance de ces conditions à la météo pour faire face au changement climatique. Conducted at REGA, a distributor-wholesaler of beverages for Hotel-Restaurant-Catering (HoReCa), this CIFRE thesis aims to make the urban logistics of a SME more environmentally responsible by improving the working conditions of its employees, while at the same time being economically sustainable. The integration of the sustainability logic accentuates the paradoxes and conflicts arising from institutional hybridity, triggering resistance to change at all levels and among all stakeholders. The research is being conducted as a research intervention, using mixed data from the research field. The results should provide an understanding of how a final intermediary SME in a logistics chain can improve the working conditions of delivery drivers by involving employees and customers in the process, and by taking account of the dependence of these conditions on the weather to cope with climate change.

Abstract Processing of granular material often requires mixing steps in order to blend cohesive powders, distribute viscous liquids into powder beds or create agglomerates from a wet powder mass. For this reason, using bladed, high-speed mixers is frequently considered a good solution by many types of industry. However, despite the importance of such mixers in powder processing, the granular flow behavior inside the mixer bowl is generally not totally understood. In this work extensive experimentation was performed comparing the behavior of a lab-scale mixer (1.9 l vessel volume) to that of a pilot-scale mixer (65 l vessel volume) with a mixture of some pharmaceutical excipients (e.g. lactose, cellulose). The aim was to propose a new and more detailed method for describing the complex powder rheology inside an high shear mixer using impeller torque, current consumption and particle image velocimetry (PIV) analysis. Particularly, a new dimensionless torque number is proposed for the torque profile analysis in order to isolate the contributions of mass fill and blade clearance at the vessel base. Impeller torque and motor current consumption were integrated with PIV to obtain more detailed information about the surface velocity and flow pattern changes in the pilot-scale mixer. Mass fill resulted to be one of the most critical variables, as predicted by the torque model, strongly affecting the powder flow patterns. An additional mixing regimes was furthermore defined according to the observation of the surface velocity of the powder bed.

Low-Cost Aviation: Society, Culture and Environment examines critical societal issues related to the advent of low-cost aviation. It is interested in how low-cost carriers (LCCs) have (re)fashioned social lives, cultural identities, and environmental responses. It situates LCCs holistically within a societal infrastructural framework rather than solely within a transport context. The book explores the changing nature of passengers’ profiles and mobile cultures, new consumption patterns and poltico-economic reconfigurations, as well as sustainability challenges. Providing a research agenda for aeromobilities, Low-Cost Aviation: Society, Culture and Environment examines the most pressing social, cultural, and political impacts of LCCs on society in different contexts around the world. It bridges transport and mobility studies, fostering transport sustainability and mobility justice to improve air transport management.Key Features:• Offers empirically grounded insights on key social issues in low-cost aviation and their implications• Draws on the expertise of an international team of scholars across the social sciences, includinggeography, anthropology, urban studies, economics, and policy studies• Utilizes case studies and examples from Asia, America, Europe, and Africa• Offers new theoretical approaches to air travel cultures and issues on climate change