AERolling element bearings are widely-used machine components and their failure can result in damage to the whole machine. A bearing failure can be caused by many factors, such as improper lubrication, the presence of abrasive particles, overloading, moisture, a corrosive environment, improper mounting, electrical discharges and material defects. These causes can be eliminated by observing the correct operating conditions, except for rolling contact fatigue (RCF). In this case, full-scale bearing life tests, or material tests for RCF resistance, are performed. Various methods of condition monitoring are used to detect damage to these components or specimens in industry or during testing in laboratories. An analysis of vibrations from the tested bearings/specimens is the most widely used method for damage detection and is based on vibration acceleration measurement and its analysis in the time or frequency domain. A more sensitive method for surface damage or subsurface crack detection is the acoustic emission (AE) method. Over the past three decades, AE-based monitoring has developed as a potential tool for rolling bearing diagnostics. This paper is aimed at the detection and monitoring of the onset and propagation of natural defects of steel specimens using AE technology. The experiments were carried out under various loading conditions on specimens of case-hardened 16MnCr5 steel. The AE signal parameters, such as count rate, cumulative count rate and RMS, were compared with vibration levels and temperature. In conclusion, the results of this study suggest that the AE monitoring method can be employed as an evaluation tool for rolling contact fatigue testing of material specimens.

The contribution summarises the experimental experience of authors with acoustic emission method application in the area of improved bearing materials contact damage stages identification on testing stations Axmat and R-mat types. The paper is focused also on the first experimental results received from measurements on real axial bearings. These results proved the acoustic emission (AE) technique enables reliable recognition of running-in period, stabilised run and exact definition of origin stage of material surface damaging, leading to the pitting. It is proposed that the direction of AE analysers utilisation not only in research area, but the AE technique may be successfully used even in industrial practice. Method of acoustic emission may offer another possibility of deepening of diagnostics of real actual state of bearing; it is, without doubt, one of new perspective areas of automated diagnostics.

Paper provides insight into possibility of asymmetrical three-phase inverter high-level control as additional grid support in low voltage networks. The asymmetrical control may assist with lowering asymmetry in areas with large single-phase load/generation penetration. Proposed and implemented control schemes are tested with laboratory equipment utilizing artificial network. Results are evaluated based on their effect on voltage asymmetry reduction and neutral conductor current magnitude.

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Je známo, že teologie Karla Rahnera je z velké části založena na filozofii. Zdá se proto smysluplné hovořit o tom, že bez alespoň základní znalosti jeho filozofie zůstane jeho teologie neprůhledná. Cílem tohoto článku je tedy podat základy Rahnerovy metafyziky, jak ji rozvinul ve svém raném a základním díle Geist in Welt (1. vydání 1939, dále GW Rahnerova filozofie se vyznačuje tím, že sama o sobě je relativně málo metodická a systematická, to je ale dáno skutečností, že Rahnerovi šlo vždy o konkrétní teologické problémy, a ne o vypracování uzavřené-ho filozofického systému.1 V Rahnerově filozofickém myšlení můžeme najít čtyři filozofické proudy, které tvořily východisko jeho myšlení: je to především klasická scholastika Tomášova, transcendentální reflexe Kantova, Maréchalův intelektuální dynamismus a existenciální filozofie Heideggerova.V tomto článku nejprve představíme zdroje Rahnerova myšlení u tří posledně jmenovaných filozofů, pak se budeme věnovat otázce jako zá-kladnímu východisku jeho metafyziky a nakonec zmíníme některé ná-mitky vůči jeho metafyzickému východisku.1 Jako teolog si Rahner nečiní žádný přímý filozofický nárok, odkazuje spíše na teologii samu, jeho teologie má však velký význam právě z hlediska filozofického. Srov. K.