65 research outputs found
Prediction of Soil Moisture Content Based On Satellite Data and Sequence-to-Sequence Networks
The main objective of this study is to combine remote sensing and machine
learning to detect soil moisture content. Growing population and food
consumption has led to the need to improve agricultural yield and to reduce
wastage of natural resources. In this paper, we propose a neural network
architecture, based on recent work by the research community, that can make a
strong social impact and aid United Nations Sustainable Development Goal of
Zero Hunger. The main aims here are to: improve efficiency of water usage;
reduce dependence on irrigation; increase overall crop yield; minimise risk of
crop loss due to drought and extreme weather conditions. We achieve this by
applying satellite imagery, crop segmentation, soil classification and NDVI and
soil moisture prediction on satellite data, ground truth and climate data
records. By applying machine learning to sensor data and ground data, farm
management systems can evolve into a real time AI enabled platform that can
provide actionable recommendations and decision support tools to the farmers.Comment: Presented on NeurIPS 2018 WiML worksho
Peculiarities of Enterprises Functioning Under Conditions of Cyclicality of the Economy
It is necessary to note that under contemporary conditions of economic management that is characterized by a high level of indefiniteness of the market environment, there is a potential risk of a decline in the activeness in economy on the macro level to the level that is below admissible. On the contrary, the interest to problems related to providing stable economic development of enterprises under conditions of unbalanced state of economy sharply grows. Under these conditions special importance is acquired by the search for regularities of economy functioning for the future development of efficient organizational and economic mechanism that can provide competitive functioning of integrated structures of the power engineering at any phase of the economic cycle. Herewith, the crisis of 2008 had a considerable unfavorable impact on the whole Russian industry.
Keywords: functioning of enterprises; business cycle; power engineering; competitiveness; post-crisis period
JEL Classifications: E32, E66, L2
Mathematical description of super-high frequencies drying process of free-running food media in device with combined energy input
At the present time the maim quantity of free-running food products, including grains, are dried in units with convective method of heat input. To intensify convective drying, general attention is paid to improving the method of moving and mixing the product with drying agent, to guarantee fast and quality drying. The use of high and super-high frequency allows can significantly intensify the drying processes, because the phenomenon of super-high frequencies energy into heat conversion throughout the processed material volume contributes to the most uniform heating of the product, compared to other heat input methods. The optimal solution for drying free-running food products is a combination of convective and high-frequency heat input methods. This combination allows controlling gradients of moisture content and temperature, changing its directions, which significantly affects quality of the resulting dry product. In this regard, combined approach to drying process modeling is of practical interest: on the one hand, there are used analytical solutions, based on physical laws application or phenomenological equations, and, on the other hand, experimentally established a relationship between temperature and moisture content of media, which is considered as a heat and mass transfer characteristic for each material
Current Distribution in the Discharge Unit of a 10-Cell Vanadium Redox Flow Battery: Comparison of the Computational Model with Experiment
Shunting currents are among the main problems of all-vanadium redox flow battery stacks since, in addition to capacity losses, they cause negative effects associated with the local destruction of electrodes and bipolar plates. The values of both the shunting currents and their destructive effects on materials can be reduced at the battery development stage by adjusting the resistance of the electrolyte supply channels. The solution to this problem can be found using a calculation model for current distribution based on the current balance in the nodes as well as voltage drops and electromotive force in internal circuits according to Kirchhoff’s laws. This paper presents the verification of the model of current distribution in an all-vanadium redox flow battery stack of an original design that allows for the determination of membrane-electrode assembly resistances and electrolyte supply channels via direct measurements. Based on a comparison of the calculated and experimental values of the coulombic efficiency of charge–discharge cycles, the capacity fade associated with the crossover of vanadium compounds through the membrane has been determined
Cascade Synthesis of Observers of Mixed Variables for Flexible Joint Manipulators Tracking Systems under Parametric and External Disturbances
This paper considers a tracking system developed for a full-actuated manipulator with flexible joints under the following assumptions: torques are control actions, and current loop dynamics are not considered; the mass-inertial characteristics of the manipulator and other parameters are not exactly known; the external matched and unmatched disturbances act on the system, and matched disturbances are not smooth; the derivatives of the reference actions are achievable but are unknown functions of time; the set of sensors is not complete. Based on the representation of the control plant model in a block form of input–output with respect to mixed variables (functions of state variables, external influences and their derivatives), we have developed a combined control law for the case where the control matrix contains additive uncertain elements. In addition, we have designed the mixed variable observers of the smallest possible dimension with piecewise linear corrective actions for two cases: (i) only the generalized coordinates of the manipulator are measured; (ii) only the angular positions and velocities of the motors are measured. It is shown that in a closed-loop system with dynamic feedback, a given tracking error stabilization accuracy is provided in the conditions of incomplete information. We presented the results of numerical simulation of these algorithms for a single-link manipulator
Low-power nuclear power plants in the context of electric power systems transformation
Increasing economic importance of the Arctic, further intensification of northern sea routes, and exceptional sensitivity of the arctic natural environment to anthropogenic impacts are fundamental factors for a comprehensive study of environmental aspects in the application of innovative technologies for the development of infrastructure in the Arctic. Despite the growing interest in low-power nuclear power plants as a distributed generation facility, their possible application in technologically isolated power systems does not lose relevance. The development of both the Arctic and Far Eastern regions of the Russian Federation presents great opportunities and demand for the use of nuclear power sources. Also, development programs for the Russian arctic zone imply a significant increase in the role and number of nuclear power facilities, in other words of potential radiation-hazardous facilities. Large-scale use of nuclear-powered installations in the Arctic necessitates advanced development of a scientifically grounded and modern forecasting system as well as assessments of threats and risks in case of possible radiation emergencies at nuclear- and radiation-hazardous facilities. Also, the development of proposals for necessary measures to minimize negative consequences of such emergencies is required. This is especially true for the case of compact placement of industrial, infrastructure and residential facilities in the Arctic in the immediate vicinity of nuclear facilities. The paper demonstrates that the demand for low-power nuclear power plants and their competitiveness will grow steadily in the conditions of electric-power industry decentralization, further spread of distributed generation and the development of technologically isolated power systems. Approaches to the generation of a low nuclear-power system based on the philosophy of industrialization of production and centralized management are presented. Special features of the environmental impact assessment of low-power nuclear power plants for the development of a methodology to study the radio-ecological hazard related problems are provided
Varidnaviruses in the human gut: A major expansion of the order Vinavirales
International audienceBacteriophages play key roles in the dynamics of the human microbiome. By far the most abundant components of the human gut virome are tailed bacteriophages of the realm Duplodnaviria, in particular, crAss-like phages. However, apart from duplodnaviruses, the gut virome has not been dissected in detail. Here we report a comprehensive census of a minor component of the gut virome, the tailless bacteriophages of the realm Varidnaviria. Tailless phages are primarily represented in the gut by prophages, that are mostly integrated in genomes of Alphaproteobacteria and Verrucomicrobia and belong to the order Vinavirales, which currently consists of the families Corticoviridae and Autolykiviridae. Phylogenetic analysis of the major capsid proteins (MCP) suggests that at least three new families should be established within Vinavirales to accommodate the diversity of prophages from the human gut virome. Previously, only the MCP and packaging ATPase genes were reported as conserved core genes of Vinavirales. Here we report an extended core set of 12 proteins, including MCP, packaging ATPase, and previously undetected lysis enzymes, that are shared by most of these viruses. We further demonstrate that replication system components are frequently replaced in the genomes of Vinavirales, suggestive of selective pressure for escape from yet unknown host defenses or avoidance of incompatibility with coinfecting related viruses. The results of this analysis show that, in a sharp contrast to marine viromes, varidnaviruses are a minor component of the human gut virome. Moreover, they are primarily represented by prophages, as indicated by the analysis of the flanking genes, suggesting that there are few, if any, lytic varidnavirus infections in the gut at any given time. These findings complement the existing knowledge of the human gut virome by exploring a group of viruses that has been virtually overlooked in previous work
Surprising dependence of the current density of bromate electroreduction on the microelectrode radius as manifestation of the autocatalytic redox-cycle (EC″) reaction mechanism
Bromate reduction from strongly acidic solutions under steady-state conditions in the presence of a very small amount of bromine has been studied voltammetrically at disk microelectrodes of various radii. In conformity with theoretical predictions the intensity of the average current density depends on the electrode size in a non-monotonous manner, passing through a maximum for a certain radius. This behavior is a direct consequence of the autocatalytic character of this process where the non-electroactive bromate anion is reduced owing to the catalytic cycle based on the bromine/bromide redox-mediator couple. The experimentally observed dependence of the maximal current density, jmax, on the inverse disc radius, 1/r0, for electrodes of larger sizes approaches a straight line corresponding to the “strong current limit”, which exceeds the diffusion-limited current density for bromate ion. Keywords: Autocatalytic cycle, Bromine/bromide redox mediation, Comproportionation reaction, Disk microelectrod
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