Efficiency and possibilities for Arabica coffee-banana management systems switching in the Mt. Elgon landscape of Uganda

Sustainably intensifying rural agricultural systems is now a development goal that has gained momentum in the recent decades due to a rapidly growing population and feeds directly into the Sustainable Development Goals of ending poverty and hunger. By 2050, the world will be inhabited by 10 billion people, 68% of whom will be city dwellers which will pose serious food and livelihoods security threats to millions of people, especially in Sub-Saharan Africa. The objective of this study was to analyse technical efficiency of four production systems in Arabica coffee-banana farming system of the Mt. Elgon in Uganda and assesses possibilities for switching from one system to another. The study was motivated by the notion that smallholder farmers do not easily adopt new systems because of opportunity costs related to input substitution, input and/or efficiency reduction and systems redesigning. We estimated a production function to measure technical efficiency and ordered the intensification pathways to create a Technical Efficiency (TE) gradient. An ordered logit model was then estimated to determine the factors influencing farmers to switch among systems, by adopting one or more following a TE gradient. Results showed that farmers produced 50% of the maximum possible Arabica coffee output, indicating huge gaps between actual and potential yields. Use of fertiliser for the lowest efficiency. Low-input-low-output pathway and improved coffee genotypes, manure and labour intensification for the higher technical efficiency clusters such as conventional and mild agroecological would also significantly increase the chances of switching from low to highly efficient and sustainable Arabica coffee production systems in the Mt. Elgon watershed of Uganda.L\u2019intensification durable des syst\ue8mes agricoles ruraux est un objectif de d\ue9veloppement durable qui a\ua0\ue9t\ue9 pris\ua0en compte pour mettre fin \ue0 la pauvret\ue9 et la faim dans une population en croissance rapide. Le monde sera habit\ue9 par 10 milliards de personnes, dont 68% seront des citadins en 2050, ce qui posera de graves menaces \ue0 la s\ue9curit\ue9 alimentaire et des moyens de subsistance de millions de personnes, en particulier en Afrique Sub-Saharienne. L\u2019objectif de cette \ue9tude \ue9tait d\u2019analyser l\u2019efficacit\ue9 de technique de quatre syst\ue8mes de production dans le syst\ue8me de culture caf\ue9-banane Arabica du mont Elgon en Ouganda et \ue9value les possibilit\ue9s de passer d\u2019un syst\ue8me \ue0 un autre. L\u2019\ue9tude \ue9tait motiv\ue9e par l\u2019id\ue9e que les petits exploitants agricoles n\u2019adoptent pas facilement de nouveaux syst\ue8mes en raison des co\ufbts d\u2019opportunit\ue9 li\ue9s \ue0 la substitution des intrants, la r\ue9duction des intrants et / ou de l\u2019efficacit\ue9 et la refonte des syst\ue8mes. Nous avons estim\ue9 une fonction de production pour mesurer l\u2019efficacit\ue9 de technique et nous avons ordonn\ue9 les voies d\u2019intensification pour cr\ue9er un gradient l\u2019efficacit\ue9 de technique (TE). Un mod\ue8le logit ordonn\ue9 a ensuite \ue9t\ue9 estim\ue9 pour d\ue9terminer les facteurs qui poussent les agriculteurs \ue0 basculer entre les syst\ue8mes, en adoptant un ou plusieurs suivant un gradient TE. Les r\ue9sultats ont montr\ue9 que les agriculteurs produisaient 50% de la production maximale possible de caf\ue9 Arabica, indiquant d\u2019\ue9normes \ue9carts entre les rendements r\ue9els et potentiels. Utilisation d\u2019engrais pour une efficacit\ue9 minimale. Une fili\ue8re \ue0 faibles intrants et \ue0 faible rendement et des g\ue9notypes de caf\ue9 am\ue9lior\ue9s, du fumier et une intensification de la main-d\u2019\u153uvre pour les grappes \ue0 plus haute efficacit\ue9 de technique telles que l\u2019agro\ue9cologie conventionnelle et douce augmenteraient \ue9galement consid\ue9rablement les chances de passer de syst\ue8mes de production de caf\ue9 Arabica faibles \ue0 tr\ue8s efficaces et durables dans le bassin versant du Mont Elgon en Ouganda

European divertor target concepts for DEMO: Design rationales and high heat flux performance

The divertor target plates are the most thermally loaded in-vessel components in a fusion reactor where high heat fluxes are produced on the plasma-facing components (PFCs) by intense plasma bombardment, radiation and nuclear heating. For reliable exhaust of huge thermal power, robust and durable divertor target PFCs with a sufficiently large heat removal capability and lifetime has to be developed. Since 2014 in the framework of the preconceptual design activities of the EUROfusion DEMO project, integrated R&D efforts have been made in the subproject ‘Target development’ of the work package ‘Divertor’ to develop divertor target PFCs for DEMO. Recently, the first R&D phase was concluded where six (partly novel) target PFC concepts were developed and evaluated by means of non-destructive inspections and high-heat-flux fatigue testing. In this paper, the major achievements of the first phase activities in this subproject are presented focusing on the design rationales of the target PFC concepts, technology options employed for small-scale mock-up fabrication and the results of the first round high-heat-flux qualification test campaign. It is reported that the mock-ups of three PFC concepts survived up to 500 loading cycles at 20 MW/m² (with hot water cooling at 130 °C) without any discernable indication of degradation in performance or structural integrity

Comparison of X-ray and neutron tomographic imaging to qualify manufacturing of a fusion divertor tungsten monoblock

Within a tokamak fusion energy device, the performance and lifespan of a divertor monoblock under high heat flux cycles is of particular interest. Key to this is the quality of manufacture, especially the material joining interfaces. Presented here is a comparative study between X-ray and neutron tomography to investigate the quality of manufactured monoblocks. Tungsten is a high attenuator of X-rays, thus X-ray tomography was performed on ‘region of interest’ samples where the majority of the tungsten armour was removed to reduce the attenuation path. Neutron tomography was performed on the full monoblock samples for non-destructive testing and on the ‘region of interest’ samples for direct comparison. Both techniques were shown to be capable of imaging the samples but having their own advantages and disadvantages relating to image accuracy and logistical feasibility. The techniques discussed are beneficial for either the research and development cycle of fusion component design or in quality assurance of manufacturing

Divertor of the European DEMO: Engineering and technologies for power exhaust

In a power plant scale fusion reactor, a huge amount of thermal power produced by the fusion reaction and external heating must be exhausted through the narrow area of the divertor targets. The targets must withstand the intense bombardment of the diverted particles where high heat fluxes are generated and erosion takes place on the surface. A considerable amount of volumetric nuclear heating power must also be exhausted. To cope with such an unprecedented power exhaust challenge, a highly efficient cooling capacity is required. Furthermore, the divertor must fulfill other critical functions such as nuclear shielding and channeling (and compression) of exhaust gas for pumping. Assuring the structural integrity of the neutron-irradiated (thus embrittled) components is a crucial prerequisite for a reliable operation over the lifetime. Safety, maintainability, availability, waste and costs are another points of consideration. In late 2020, the Pre-Conceptual Design activities to develop the divertor of the European demonstration fusion reactor were officially concluded. On this occasion, the baseline design and the key technology options were identified and verified by the project team (EUROfusion Work Package Divertor) based on seven years of R&D efforts and endorsed by Gate Review Panel. In this paper, an overview of the load specifications, brief descriptions of the design and the highlights of the technology R&D work are presented together with the further work still needed

Interpretative and predictive modelling of Joint European Torus collisionality scans

Transport modelling of Joint European Torus (JET) dimensionless collisionality scaling experiments in various operational scenarios is presented. Interpretative simulations at a fixed radial position are combined with predictive JETTO simulations of temperatures and densities, using the TGLF transport model. The model includes electromagnetic effects and collisions as well as □(→┬E ) X □(→┬B ) shear in Miller geometry. Focus is on particle transport and the role of the neutral beam injection (NBI) particle source for the density peaking. The experimental 3-point collisionality scans include L-mode, and H-mode (D and H and higher beta D plasma) plasmas in a total of 12 discharges. Experimental results presented in (Tala et al 2017 44th EPS Conf.) indicate that for the H-mode scans, the NBI particle source plays an important role for the density peaking, whereas for the L-mode scan, the influence of the particle source is small. In general, both the interpretative and predictive transport simulations support the experimental conclusions on the role of the NBI particle source for the 12 JET discharges

Food Systems Resilience : Towards an Interdisciplinary Research Agenda

In this article, we offer a contribution to the ongoing study of food by advancing a conceptual framework and interdisciplinary research agenda – what we term ‘food system resilience’. In recent years, the concept of resilience has been extensively used in a variety of fields, but not always consistently or holistically. Here we aim to theorise systematically resilience as an analytical concept as it applies to food systems research. To do this, we engage with and seek to extend current understandings of resilience across different disciplines. Accordingly, we begin by exploring the different ways in which the concept of resilience is understood and used in current academic and practitioner literatures - both as a general concept and as applied specifically to food systems research. We show that the social-ecological perspective, rooted in an appreciation of the complexity of systems, carries significant analytical potential. We first underline what we mean by the food system and relate our understanding of this term to those commonly found in the extant food studies literature. We then apply our conception to the specific case of the UK. Here we distinguish between four subsystems at which our ‘resilient food systems’ can be applied. These are, namely, the agro-food system; the value chain; the retail-consumption nexus; and the governance and regulatory framework. On the basis of this conceptualisation we provide an interdisciplinary research agenda, using the case of the UK to illustrate the sorts of research questions and innovative methodologies that our food systems resilience approach is designed to promote