On three-dimensional reconstruction of optically thin solar emission sources

Calculations are given for constructing the three dimensional distribution of optically thin EUV emission sources associated with solar active regions, from two dimensional observations (projections) recorded by the spectroheliograph on the OSO 7 satellite. The relation of the method to other image reconstruction methods is briefly discussed as well as the special requirements imposed in the solar case such as a knowledge of the true solar rotation function. A useful correlation criterion for establishing the physical validity of solutions is given

How Much Time Does a Farmer Spend to Produce My food? An International Comparison of the Impact of Diets and Mechanization

Work is one of the main inputs in agriculture. It can be performed by humans, animals, or machinery. Studies have shown strong differences throughout the world in labour required to produce a kilogram of food. We complement this line of research by linking these data to food consumption patterns, which are also strongly different throughout the world. We calculate the hours of farm labour required to produce a person’s annual food consumption for four scenarios. These scenarios are comprised of two extreme cases for production systems and diets, respectively, that illustrate prevailing global differences. Our results show that the farm labour requirements differ by a factor of about 200 among production systems, and by a factor of about two among consumption patterns. The gain in farm labour efficiency with mechanization is enormous: only 2–5 hours of farm labour are needed to produce the food consumed by a person in a year. This value is much lower than the time an average person spends on buying food, cooking, or eatin

Rapid growth in agricultural trade: effects on global area efficiency and the role of management

Cropland is crucial for supplying humans with biomass products, above all, food. Globalization has led to soaring volumes of international trade, resulting in strongly increasing distances between the locations where land use takes place and where the products are consumed. Based on a dataset that allows tracing the flows of almost 450 crop and livestock products and consistently allocating them to cropland areas in over 200 nations, we analyze this rapidly growing spatial disconnect between production and consumption for the period from 1986 to 2009. At the global level, land for export production grew rapidly (by about 100 Mha), while land supplying crops for direct domestic use remained virtually unchanged. We show that international trade on average flows from high-yield to low-yield regions: compared to a hypothetical no-trade counterfactual that assumes equal consumption and yield levels, trade lowered global cropland demand by almost 90 Mha in 2008 (3-year mean). An analysis using yield gap data (which quantify the distance of prevailing yields to those attainable through the best currently available production techniques) revealed that differences in land management and in natural endowments contribute almost equally to the yield differences between exporting and importing nations. A comparison of the effect of yield differences between exporting and importing regions with the potential of closing yield gaps suggests that increasing yields holds greater potentials for reducing future cropland demand than increasing and adjusting trade volumes based on differences in current land productivity.Peer Reviewe

The DeMaDs Open Source Modeling Framework for Power System Malfunction Detection

Modeling and simulation of electrical power systems are becoming increasingly important approaches for the development and operation of novel smart grid functionalities -- especially with regard to data-driven applications as data of certain operational states or misconfigurations can be next to impossible to obtain. The DeMaDs framework allows for the simulation and modeling of electric power grids and malfunctions therein. Furthermore, it serves as a testbed to assess the applicability of various data-driven malfunction detection methods. These include data mining techniques, traditional machine learning approaches as well as deep learning methods. The framework's capabilities and functionality are laid out here, as well as explained by the means of an illustrative example.Comment: 2023 Open Source Modelling and Simulation of Energy Systems (OSMSES

Deforestation displaced: trade in forest-risk commodities and the prospects for a global forest transition

While many developed countries are increasing their forest cover, deforestation is still rife in the tropics and subtropics. With international trade in forest-risk commodities on the rise, it is becoming increasingly important to consider between-country trade linkages in assessing the drivers of-and possible connections between-forest loss and gain across countries. Previous studies have shown that countries that have undergone a forest transition (and are now increasing their forest cover) tend to displace land use outside their borders. However, lack of comprehensive data on deforestation drivers imply that it has not been possible to ascertain whether this has accelerated forest loss in sourcing countries. To remedy this, we present a land-balance model that quantifies deforestation embodied in production of agricultural and forestry commodities at country level across the tropics and subtropics, subsequently tracing embodied deforestation to countries of apparent consumption using a physical, country-to-country trade model. We find that in the period 2005-2013,62% (5.5 Mha yr(-1)) of forest loss could be attributed to expanding commercial cropland, pastures and tree plantations. The commodity groups most commonly associated with deforestation were cattle meat, forestry products, oil palm, cereals and soybeans, though variation between countries and regions was large. Alarge (26%) and slightly increasing share of deforestation was attributed to international demand, the bulk of which (87%) was exported to countries that either exhibit decreasing deforestation rates or increasing forest cover (late-or post-forest transition countries), particularly in Europe and Asia (China, India, and Russia). About a third of the net forest gains in post-forest transition countries was in this way offset by imports of commodities causing deforestation elsewhere, suggesting that achieving a global forest transition will be substantially more challenging than achieving national or regional ones

Linking country level food supply to global land and water use and biodiversity impacts : The case of Finland

The agricultural products consumed in Finland are increasingly grown on foreign farms. We analyze the Finnish imports of food and feed crops from 1986 to 2011 by products and by their geographic origin drawing a link to environmental impacts. The share of foreign crops consumed in Finland nearly doubled in the study period. The imports increased especially with commodities that could also be produced domestically. While the production of food increasingly shifted abroad, also the exports from Finland increased. >90% of the blue water of the Finnish crop supply came from foreignwater resources. Wemap the results of land and water use together with their impacts on global biodiversity, and show thatmost of the land and water use related biodiversity impacts (>93%) associated with the Finnish food consumption are related to the imports and therefore taken place outside the Finnish borders. The use ofmultiple environmental indicators can help identifying products and spatial hotspots associated with themost severe environmental impacts of the Finnish crop imports contributing to a more holistic decision-making and the promoting of sustainable food consumption both domestically and globally. (C) 2016 Elsevier B. V. All rights reserved.Peer reviewe

Global cropland and greenhouse gas impacts of UK food supply are increasingly located overseas

Funding This work was supported by a University of Aberdeen Environment and Food Security Theme/the James Hutton Institute PhD studentship, and contributes to the Scottish Food Security Alliance-Crops and the Belmont Forum supported DEVIL project (NERC fund UK contribution: NE/M021327/1). J.M. and R.B.M. acknowledge funding from the Rural and Environment Science and Analytical Services, Scottish Government. T.K. acknowledges funding from the European Research Council Grant ERC-263522 (LUISE).Peer reviewedPostprin

Model-Based Control of a Large-Scale Ball-on-Plate System With Experimental Validation

A ball-on-plate system is a widespread education oriented laboratory experiment for automation in mechatronics. The setup combines elements of mechanical, electrical and control engineering and is an adequate setup for learning the combination of theory and practice. This paper presents an example of a workshop result on automatic control in mechatronics. The aim of the workshop is to develop and compare model-based approaches for ball position control in a given large-scale ball-on-plate system. The result includes the derivation of a non-linear state space model of the system. The equations are linearized in the center of the horizontal plate as an operating point in order to apply cascade control, linear-quadratic optimal control and PI optimal state feedback control. The algorithms are implemented on a microcontroller and tested in the experimental setup. The results show a successful control development which achieves the control goal with good performance in terms of command response