33,785 research outputs found

    Sustainable and healthy diets: trade-offs and synergies : final scientific report

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    This project aimed at analysing trade-offs and synergies between healthy nutrition and sustainable food systems. First, we identified nutritional patters of the Swiss population based on representative consumption data. The health impacts of these nutritional patterns were then analysed based on a review of the scientific literature on health impacts of food commodities and diets and by calculating the Alternate Healthy Eating Index (AHEI), the Mediterranean Diet Score (MDS) and Disability Adjusted Life Years (DALYs) of the nutritional patterns. Second, we comprehensively analysed health, environmental, social and economic impacts and related trade-offs and synergies for a number of future scenarios of Swiss agricultural production and food consumption. For this, we used a modelling approach, linking three different models: a global mass flow model, a system dynamics model and an environmentally extended input-output model. We modelled ten different scenarios for the Swiss Food Sector in 2050. These scenarios were either developed in a participatory process during a series of interviews and group discussions with different groups of stakeholders or optimised environmental impacts while at the same time complying with different nutritional and agronomic restrictions. Three main scenarios were analysed with all three models in detail. Among these main scenarios was the SwissFoodPyramid2050 Scenario, which assumes a widespread implementation of the nutritional recommendations according to the Swiss Food Pyramid. The FeedNoFood2050 Scenario assumes an improved use of agricultural land by feeding only grass and by-products to livestock, which was not competing with direct human nutrition, i.e. did not require arable land (neither in Switzerland nor abroad). The third scenario was a reference scenario, which assumes no changes in diets until 2050 and which was used to compare the two alternative scenarios. The other scenarios were targeted at specific questions such as minimizing greenhouse gases. Our results illustrate two visions of how healthy diets and sustainable food systems could look like. Both the SwissFoodPyramid2050 and the FeedNoFood2005 scenarios would require similar dietary changes, such as a reduction of meat consumption and an increase of consumption of pulses. However, there are also fundamental differences between the diets in the two alternative scenarios, e.g. regarding the type of meat consumed. These differences can be interpreted as trade-offs which result from agronomic boundary conditions such as the coupled production of milk and meat, the availability of natural resources, such as grassland and co-products of food processing and health aspects of Swiss diets. Of primary importance in this respect was the use of permanent grasslands and the co-production of veal and beef with dairy production due to environmental reasons and reasons for optimally utilizing available resources. This means, if permanent grassland should be maintained as an ecosystem, dairy production would provide the basis for animal proteins. Thus, while in the FeedNoFood2050 Scenario veal and rather low-quality beef from dairy cows is consumed instead of meat from monogastrics, the SwissFoodPyramid2050 Scenario would result in a higher amount of meat from monogastrics. Our results imply that there is a lack of a comprehensive food systems view in the current discussion on healthy and sustainable diets. Stronger coherence between health, food and agricultural policy is needed to account for systemic boundary conditions and thus to allow for minimising trade-offs and maximise synergies. Current agricultural policies fail to address the health perspective. Financial support for meat and sugar producers, which lead to lower prices for those products and ultimately to a higher consumption than without these policies, are two obvious examples. Yet, comprehensive visions such as the SwissFoodPyramid scenario, the FeedNoFood Scenario or optimised scenarios would require an even more complex policy mix of incentives, regulations and information campaigns. This would probably need an adaptation of the current institutional setting and division of competences between the Federal Offices for Agriculture (FOAG) and for the Environment (FOEN), the State Secretariat for Economic Affairs (SECO) and the Federal Food Safety and Veterinary Office (FSVO). A commonly shared vision, including specific goals with respect to how the Swiss food system should look like, is urgently needed. Developing such a vision needs to involve all operators and stakeholders of the food system, as our results imply that more sustainable and healthy diets do not necessarily go along with financial benefits of both producers and consumers. These trade-offs and the knowledge of behavioural economics need to be considered for designing settings which create mutual benefits for operators in the food sector. For instance, neither the majority of consumers, food industry nor agricultural producers can be expected to respond altruistically as an entire sector in the long term. Therefore, policy needs to set financial incentives for internalising environmental and social externalities in order to push and pull the food system towards sustainability. Furthermore, it is crucial to account for agronomic boundary conditions and systemic aspects, such as the role of ruminants in utilizing grasslands and the unavoidable link of milk and meat production

    Generator Power Optimisation for a More-Electric Aircraft by Use of a Virtual Iron Bird

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    A prodedure is developed to minimise the generator design power within the electric power system of a future more-/ all-electric aircraft. This allows to save weight on the generators and on other equipment of the electic power system. Execution of the optimisation procedure by hand demonstrates the complexity of the problem. An automation of the process shows the capabilities of integrated modelling, simulation and optimisation tools

    Design and development of auxiliary components for a new two-stroke, stratified-charge, lean-burn gasoline engine

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    A unique stepped-piston engine was developed by a group of research engineers at Universiti Teknologi Malaysia (UTM), from 2003 to 2005. The development work undertaken by them engulfs design, prototyping and evaluation over a predetermined period of time which was iterative and challenging in nature. The main objective of the program is to demonstrate local R&D capabilities on small engine work that is able to produce mobile powerhouse of comparable output, having low-fuel consumption and acceptable emission than its crankcase counterpart of similar displacement. A two-stroke engine work was selected as it posses a number of technological challenges, increase in its thermal efficiency, which upon successful undertakings will be useful in assisting the group in future powertrain undertakings in UTM. In its carbureted version, the single-cylinder aircooled engine incorporates a three-port transfer system and a dedicated crankcase breather. These features will enable the prototype to have high induction efficiency and to behave very much a two-stroke engine but equipped with a four-stroke crankcase lubrication system. After a series of analytical work the engine was subjected to a series of laboratory trials. It was also tested on a small watercraft platform with promising indication of its flexibility of use as a prime mover in mobile platform. In an effort to further enhance its technology features, the researchers have also embarked on the development of an add-on auxiliary system. The system comprises of an engine control unit (ECU), a directinjector unit, a dedicated lubricant dispenser unit and an embedded common rail fuel unit. This support system was incorporated onto the engine to demonstrate the finer points of environmental-friendly and fuel economy features. The outcome of this complete package is described in the report, covering the methodology and the final characteristics of the mobile power plant

    Quantum picturalism for topological cluster-state computing

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    Topological quantum computing is a way of allowing precise quantum computations to run on noisy and imperfect hardware. One implementation uses surface codes created by forming defects in a highly-entangled cluster state. Such a method of computing is a leading candidate for large-scale quantum computing. However, there has been a lack of sufficiently powerful high-level languages to describe computing in this form without resorting to single-qubit operations, which quickly become prohibitively complex as the system size increases. In this paper we apply the category-theoretic work of Abramsky and Coecke to the topological cluster-state model of quantum computing to give a high-level graphical language that enables direct translation between quantum processes and physical patterns of measurement in a computer - a "compiler language". We give the equivalence between the graphical and topological information flows, and show the applicable rewrite algebra for this computing model. We show that this gives us a native graphical language for the design and analysis of topological quantum algorithms, and finish by discussing the possibilities for automating this process on a large scale.Comment: 18 pages, 21 figures. Published in New J. Phys. special issue on topological quantum computin

    Solar Reector Design

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    The design of solar panels is investigated. Different aspects of this problem are presented. A formula averaging the solar energy received on a given location is derived rst. The energy received by the collecting solar panel is then calculated using a specially designed algorithm. The geometry of the device collecting the energy may then be optimised using different algorithms. The results show that for a given depth, devices of smaller width are more energy efficient than those of wider dimensions. This leads to a more economically efficient design
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