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Upwelling processes bring nutrient-rich waters from the deep ocean to the surface. Areas of upwelling are often associated with high productivity, offering great economic value in terms of fisheries. The sensitivity of spring/summer-time coastal upwelling systems to climate change has recently received a lot of attention. Several studies have suggested that their intensity may increase in the future while other authors have shown decreasing intensity in their equatorward portions. Yet, recent observations do not show robust evidence of this intensification. The Senegalo-Mauritanian upwelling system (SMUS) located at the southern edge of the north Atlantic system (12°N–20°N) and most active in winter/spring has been largely excluded from these studies. Here, the seasonal cycle of the SMUS and its response to climate change is investigated in the database of the Coupled Models Inter comparison Project Phase 5 (CMIP5). Upwelling magnitude and surface signature are characterized by several sea surface temperature and wind stress indices. We highlight the ability of the climate models to reproduce the system, as well as their biases. The simulations suggest that the intensity of the SMUS winter/spring upwelling will moderately decrease in the future, primarily because of a reduction of the wind forcing linked to a northward shift of Azores anticyclone and a more regional modulation of the low pressures found over Northwest Africa. The implications of such an upwelling reduction on the ecosystems and local communities exploiting them remains very uncertain.

In Cameroon, as in other countries of the Congo basin region, policy processes and activities related to climate change have been hitherto geared mostly towards mitigation and related questions, with limited concern about adaptation issues. However, the increasing vulnerability of Cameroon to climate variability and change makes adaptation significant to its national climate-change policy. Nonetheless, it remains a challenge to make both adaptation and mitigation occupy the same policy space in Cameroon. This paper builds partly on studies carried out in two community forest carbon initiatives in the southern rainforest of Cameroon. It also argues, supported by existing literature on adaptation and mitigation, that mitigation activities have the potential to produce adaptation outcomes; a situation which avoids duplication of efforts and waste of financial and technical resources, if synergetic options are anticipated and planned. However, whether such integrated approaches succeed and are subsequently reflected in national-level climate policy depends on how actors across different sectors and at different levels engage and carry out their roles. The paper discusses these roles and how they can support each other in pursuing integrated initiatives – a context which is vital for Cameroon.

Abstract The integrity of PWR pressure vessels is assured by keeping the crack tip stress intensity factor below the toughness of the material under monotonic isothermal loading. To study the effects of sudden cooling associated with a thermal gradient, a specially modified compact specimen has been developed. This has been used to carry out tests in the transition zone with different loading-temperature sequences liable to call the conventional criteria into question. The test is described in detail in Part I of this article [Chapuliot S, et al. Thermomechanical analysis of thermal shock fracture in the brittle/ductile transition zone. Part I: Description of the tests. Engng Fract Mech, 72, 2005, 661–73]. The second part describes numerical investigations to estimate the local mechanical fields at the crack tip and the overall parameters of the fracture mechanics. Finite element thermomechanical calculations are used to interpret the results of these new thermal shock tests using the master curve concept [ASTM E 1921–1997. Standard test method for determination of reference temperature To for ferritic steels in the transition range, 1997] and the Beremin statistical model [Beremin FM. A local criterion for cleavage fracture of a nuclear pressure vessel steel. Metall Trans A, 14A, November 1983, 2287–777].

International audience ; This paper proposes a Deep Reinforcement Learning approach for optimally managing multi-energy systems in smart grids. The optimal control problem of the production and storage units within the smart grid is formulated as a Partially Observable Markov Decision Process (POMDP), and is solved using an actor-critic Deep Reinforcement Learning algorithm. The framework is tested on a novel multi-energy residential microgrid model that encompasses electrical, heating and cooling storage as well as thermal production systems and renewable energy generation. One of the main challenges faced when dealing with real-time optimal control of such multi-energy systems is the need to take multiple continuous actions simultaneously. The proposed Deep Deterministic Policy Gradient (DDPG) agent has shown to handle well the continuous state and action spaces and learned to simultaneously take multiple actions on the production and storage systems that allow to jointly optimize the electrical, heating and cooling usages within the smart grid. This allows the approach to be applied for the real-time optimal energy management of larger scale multi-energy Smart Grids like eco-distrits and smart cities where multiple continuous actions need to be taken simultaneously.

Methodology: To carry out the calculation of these agroclimatic indicators, daily data of the following climatic variables were used at a resolution of 5 km: Maximum and minimum temperatures (source: CHIRTS), precipitation (source: CHIRPS), solar radiation (AGMERRA), data of soil (SoilGrids). The indicators were calculated for each month during a period of 33 years (1983 - 2016). With the above, the indicators were calculated per month during 1983 -2016 and finally, in order to summarize the calculated indicators, an aggregation of data was carried out, calculating the average in the following time periods: 1983 - 2016, 1990 - 2016, 1995 - 2016, 2000 – 2016, 2005 – 2016, 2010 – 2016 The purpose for which these indicators were created is to group or characterize the different accessions available in the Genesys database, considering climatic data from where they were collected. For the above, it is necessary to carry out a characterization of zones based on agroclimatic indicators, which are framed in evaluating the following stresses: Heat, Drought and Flooding, in addition to including indicators that capture the behavior of the photoperiod.

The environmental crisis drives the integration of renewable energy sources into grids, leading to the emergence of microgrids for power supply in rural and urban areas. However, microgrid adoption faces stability and energy management challenges that require resilient control structures and intelligent mechanisms. This thesis proposes a hierarchical control structure for a standalone residential microgrid system, combining solar, fuel cell, and hybrid energy storage (battery and supercapacitor). The control technique employed is model-free super twisting sliding mode control with anti-windup for saturation. The control structure aims to ensure a stable and resilient microgrid with desired DC bus voltage stability, validated through simulation tests and hardware-in-the-loop experiments. Additionally, the thesis proposes a novel optimized energy management strategy (EMS) focusing on power sharing and battery state of charge regulation, considering the tradeoff between battery usage and hydrogen consumption costs. Simulation tests confirm the successful achievement of the intended goals by the EMS. ; La crise environnementale pousse à l’intégration des énergies renouvelables dans les micro-réseaux pour les zones rurales et urbaines. Cependant, l’adoption des micro réseaux rencontre des défis de stabilité et de gestion de l’énergie nécessitant des contrôles résilients. Cette thèse propose une structure de contrôle hiérarchique pour un micro-réseau autonome résidentiel, combinant énergie solaire,pile à combustible et stockage hybride(Battery et supercondensateur). La technique de contrôle utilisée est le contrôle en mode glissant super twisting sans modèle avec antidépassement pour la saturation. La structure de contrôle vise à assurer un micro-réseaustable et résilient avec une stabilité souhaité ede la tension du bus continu, validée par des tests de simulation et des expériences en boucle fermée. De plus, la thèse propose une nouvelle stratégie de gestion optimisée de l’énergie (EMS) axée sur le partage de ...

This document contains a review of global digital resources relevant to climate-informed agroecological transitions. The purpose of the review was to catalog relevant digital resources and assess their role in inclusive knowledge development, with special attention to farmers’ co-creation of knowledge for on-the-ground practices. To this end, we identified existing digital tools relevant to technical advisory and performance assessment and reviewed their functions (i.e., the purpose of using a tool) against indicators for exemplary features (i.e., the channels in which a user can engage with the tool) that could support socially inclusive, climate-informed agroecological transitions.<br><br> Metodology:To evaluate exemplary features of agricultural digital tools – defined here as an app, online resource (not platforms), or other software available on a digital device (e.g., phone, smartphone, computer, etc.), including those that are language, audio, and visually based – we developed 87 indicators (see Indicators Explained) relating to seven categories: (i) performance assessment, (ii) technological specifications, (iii) social inclusion and co-creation, (iv) scaling, (v) climate change adaptation, mitigation and whether the tool calculates greenhouse gas emissions, and (vi) agroecological principles Exemplariness was defined in this review as best fitting the requirements of the target users and best addressing agroecological and climate change mitigation and/or adaption outcomes. All indicators for categories i-v were developed and validated via several rounds of internal reviews and expert consultations. The 12 agroecological indicators (i.e., principles) were adopted and refined from the FAO 10 Elements of Agroecology (FAO, 2018), HLPE (HLPE, 2019) and TAPE (FAO, 2019) reports. Sixty (60) tools were selected for a full review against the 87 indicators based on their applicability to provide technical advisory and/or performance assessment on climate-informed agroecological transitions. Tools were classified as technical advisory resources if they delivered any recommendations regarding farming practices and as performance assessment resources if they included review of farm status or operations. Tools were mostly identified via Google searches, expert interviews, and platforms such as the CGIAR Evidence Clearing House and Digital Agri Hub. Each tool was reviewed by one analyst by accessing the tool, when available, or by reviewing materials online. A second analyst validated individual indicator responses when subjectivity in responses was an issue. Indicators were marked as ‘unknown’ when subjectivity in responses persisted or when information was not available.