Comparison of tillage systems in terms of water infiltration into the soil during the autumn season

ArticleThe soil belongs to the most valuable parts of the planet Earth. It is, endangered by water erosion, which causes huge destruction every year, or damage to farmland. More than half of the agricultural land in the Czech Republic is threatened by water erosion. The measurement was performed in the location Nesperská Lhota. The trial has been established on loamy sand Cambisol. In the field experiment, there were created 6 different variants which wad differed by soil tillage and crop. In the individual variants maize and oats were located. The field trial has been existing for a long time, as it was founded in 2009. Two measuring methods of water infiltration were used for the measurements: a mini disk infiltrometer and a single ring. The measurement was performed in the period of September 2016 before the harvest of maize. The soil aggregates were already stabilized at that time after all tillage operations. The measurement result showed the difference between the methods of soil tillage. The greatest ability of infiltration had a variant of maize with inter-row oats. Surprisingly, it was followed by maize, which was processed by ploughing technology. The lowest infiltration capacity was showed by oats reduced by soil tillage. A variant without vegetation had the second lowest infiltration. Our results obtained at rate of water infiltration into the soil affirm the need to control measures in the late vegetative stages. It is important for most of the rainfall to be quickly infiltrated so that it prevents the formation of massive surface runoff

Compressor cascade total pressure loss correlation modelling at design points using artificial neural networks

grant No. SGS22/148/OHK2/3T/12, project TK03030121 Conceptual Design of an Innovative Safety System for Gas-cooled Nuclear Reactor

Compressor cascade correlations modelling at design points using artificial neural networks

In recent years, the flow analysis by means of computational fluid dynamics (CFD) has become a useful design and optimization tool. Unfortunately, despite advances in the computational power, numerical simulations are still very time consuming. Thus, empirical correlation models keep their importance as a tool for early stages of axial compressor design and for prediction of basic performance parameters. These correlations were developed based on experimental data obtained from 2D measurements performed on cases of classical airfoils such as the NACA 65-series or C.4 profiles. There is insufficient amount of experimental data for other families of airfoils, but CFD simulations can be used instead and their results correlated using artificial neural networks (ANN), as described in this work. Unlike the classical deep learning approach using perceptrons, this work presents neural networks employing higher order neural units

Off-equatorial orbits in strong gravitational fields near compact objects

Near a black hole or an ultracompact star, motion of particles is governed by strong gravitational field. Electrically charged particles feel also electromagnetic force arising due to currents inside the star or plasma circling around. We study a possibility that the interplay between gravitational and electromagnetic action may allow for stable, energetically bound off-equatorial motion of charged particles. This would represent well-known generalized Stormer's 'halo' orbits, which have been discussed in connection with the motion of dust grains in planetary magnetospheres. We demonstrate that such orbits exist and can be astrophysically relevant when a compact star or a black hole is endowed with a dipole-type magnetic field. In the case of Kerr-Newman solution, numerical analysis shows that the mutually connected gravitational and electromagnetic fields do not allow existence of stable halo orbits above the outer horizon of black holes. Such orbits are either hidden under the inner black-hole horizon, or they require the presence of a naked singularity.Comment: 16 pages, 7 figures, accepted in Class. Quantum Grav. (2008

Report on workshop A1: Exact solutions and their interpretation

I report on the communications and posters presented on exact solutions and their interpretation at the GRG18 Conference, Sydney.Comment: 9 pages, no figures. Many typos corrected. Report submitted to the Proceedings of GR18. To appear in CQ

E-Democracy and the European Public Sphere

The chapter starts with an outline of outstanding recent contributions to the discussion of the EU democratic deficit and the so-called “no demos” problem and the debate about European citizenship and European identity—mainly in the light of insights from the EU crisis. This is followed by reflections on the recent discussion on the state of the mass media-based European public sphere. Finally, the author discusses the state of research on the Internet’s capacity to support the emergence of a (renewed) public sphere, with a focus on options for political actors to use the Internet for communication and campaigning, on the related establishment of segmented issue-related publics as well as on social media and its two-faced character as an enabler as well as a distorting factor of the public sphere. The author is sceptic about the capacities of Internet-based political communication to develop into a supranational (European) public sphere. It rather establishes a network of a multitude of discursive processes aimed at opinion formation at various levels and on various issues. The potential of online communication to increase the responsiveness of political institutions so far is set into practice insufficiently. Online media are increasingly used in a vertical and scarcely in a horizontal or interactive manner of communication