MODERNIZATION OF IRRIGATION SYSTEMS MANAGEMENT TO IMPROVE THEIR RELIABILITY

Results of many years of theoretical, operational and reclamation studies conducted in various climatic-economic conditions of the Republic of Uzbekistan are presented in the paper. Based on the research and experience data of developed countries, recommendations have been developed for modernizing the management of irrigation systems based on the cybernetic scheme model in order to increase the reliability coefficients of all parts of the system, as well as to increase the reliability coefficient and coefficient of performance (COP) of the Lower Syrdarya irrigation system

Verification of stiffness and surface treatment of axial bearing levers by static tests

To eliminate misalignment between stator and rotor (especially in large rotary machines) the thrust bearing with a system of very precise manufactured levers has started to be used. The article deals with the static tests of self-equalizing elements (levers) made of 34CrNiMo6 steel, which are the critical parts of a newly developing self-equalizing thrust bearing. To verify the stiffness of the newly designed levers by static tests, the real levers were produced, which according to preliminary experiments and numerical simulations have the potential to be used the most in turbines. Based on basic tests of the pairs samples, that represent types of geometries going in contact within real conditions, it was found out that in terms of the surface treatment, the best results show electroless nickel-plated samples. So, due to this reason, the real levers were produced and their surfaces were processed in this way by electroless nickel-plating. Within the presented research, they were statically tested intending to determine the surface integrity and whether there was any development of damage to the surface layer. The evaluation was done using a stereomicroscope and a scanning electron microscope. The tests confirm sufficient rigidity of the levers including a suitable method of surface processing. Although, in some cases, these were surface defects caused by surface treatment technology, but no defects were found after static loading. © 2020 The Authors. Published by Elsevier B.V.Ministry of Education of the Slovak Republic [KEGA 007TUKE-4/2018, APVV-19-0550, VEGA 1/0812/21, KEGA 005TUKE-4/2021

Observation of a tropopause fold by MARA VHF wind-profiler radar and ozonesonde at Wasa, Antarctica : comparison with ECMWF analysis and a WRF model simulation

Tropopause folds are one of the mechanisms of stratosphere-troposphere exchange, which can bring ozone rich stratospheric air to low altitudes in the extra-tropical regions. They have been widely studied at northern mid- or high latitudes, but so far almost no studies have been made at mid- or high southern latitudes. The Moveable Atmospheric Radar for Antarctica (MARA), a 54.5 MHz wind-profiler radar, has operated at the Swedish summer station Wasa, Antarctica (73A degrees S, 13.5A degrees W) during austral summer seasons from 2007 to 2011 and has observed on several occasions signatures similar to those caused by tropopause folds at comparable Arctic latitudes. Here a case study is presented of one of these events when an ozonesonde successfully sampled the fold. Analysis from European Center for Medium Range Weather Forecasting (ECMWF) is used to study the circumstances surrounding the event, and as boundary conditions for a mesoscale simulation using the Weather Research and Forecasting (WRF) model. The fold is well resolved by the WRF simulation, and occurs on the poleward side of the polar jet stream. However, MARA resolves fine-scale layering associated with the fold better than the WRF simulation

Response of polar mesosphere summer echoes to geomagnetic disturbances in the Southern and Northern Hemispheres : the importance of nitric oxide

The relationship between polar mesosphere summer echoes (PMSE) and geomagnetic disturbances (represented by magnetic K indices) is examined. Calibrated PMSE reflectivities for the period May 2006-February 2012 are used from two 52.0/54.5 MHz radars located in Arctic Sweden (68 degrees N, geomagnetic latitude 65 degrees) and at two different sites in Queen Maud Land, Antarctica (73 degrees/72 degrees S, geomagnetic latitudes 62 degrees/63 degrees). In both the Northern Hemisphere (NH) and the Southern Hemisphere (SH) there is a strong increase in mean PMSE reflectivity between quiet and disturbed geomagnetic conditions. Mean volume reflectivities are slightly lower at the SH locations compared to the NH, but the position of the peak in the lognormal distribution of PMSE reflectivities is close to the same at both NH and SH locations, and varies only slightly with magnetic disturbance level. Differences between the sites, and between geomagnetic disturbance levels, are primarily due to differences in the high-reflectivity tail of the distribution. PMSE occurrence rates are essentially the same at both NH and SH locations during most of the PMSE season when a sufficiently low detection threshold is used so that the peak in the lognormal distribution is included. When the local-time dependence of the PMSE response to geomagnetic disturbance level is considered, the response in the NH is found to be immediate at most local times, but delayed by several hours in the afternoon sector and absent in the early evening. At the SH sites, at lower magnetic latitude, there is a delayed response (by several hours) at almost all local times. At the NH (auroral zone) site, the dependence on magnetic disturbance is highest during evening-to-morning hours. At the SH (sub-auroral) sites the response to magnetic disturbance is weaker but persists throughout the day. While the immediate response to magnetic activity can be qualitatively explained by changes in electron density resulting from energetic particle precipitation, the delayed response can largely be explained by changes in nitric oxide concentrations. Observations of nitric oxide concentration at PMSE heights by the Odin satellite support this hypothesis. Sensitivity to geomagnetic disturbances, including nitric oxide produced during these disturbances, can explain previously reported differences between sites in the auroral zone and those at higher or lower magnetic latitudes. The several-day lifetime of nitric oxide can also explain earlier reported discrepancies between high correlations for average conditions (year-by-year PMSE reflectivities and K indices) and low correlations for minute-to-day timescales

Analysing how law shapes journalism in Central and Eastern Europe: the case of the 2008 Slovak Press Act

This article investigates the operation of the contested reply and correction provisions of the 2008 Slovak Press Act and their influence on journalism. I argue that apart from the 'law-on-the-books', we need to examine the interactions between the media, policymakers and judges in order to explain how law shapes journalism in the public spheres of Central and Eastern European democracies. Such interactions are based on the interests and experiences of the actors and conditioned by their particular historical, structural, cultural and international contexts. Our analysis thus needs to take them all into account when assessing the role of legislation