The nonlinear development of magnetic reoonnection in a
current-sheet system is studied numerically. The reconnection process, developing from an initial localized enhancement of electirical resistivity, is at some instants interrupted by a sharp decrease in electrical resistivity, The development of this process is studied and the results discussed within the scope of the solar flare theory.
Article deals with creation of mathematical - statistical model of cutting forces at turning of steel ISO 683/1-87 by means of regression and correlation analysis. It has been identified the significance of that factors that influence the investigated parameter. and Článok sa zaoberá vytvorením matematicko - štatistického modelu rezných síl pri pozdĺžnom sústružení ocele ISO 683/1-87 s použitím metód regresnej a korelačnej analýzy, ako aj identifikáciou významnosti týchto faktorov na skúmaný parameter.
The air refractive index is an important parameter in interferometric length measurements, since it substantially affects the measurement accuracy. We present a refractive index of air measurement method based on measuring the optical path difference between the ambient air and the vacuum inside a permanently evacuated double-spaced cell using a combination of laser and low-coherence interferometry. and Při interferometrických měřeních délky je jednou z klíčových měřených veličin hodnota indexu lomu vzduchu, neboť může zásadním způsobem ovlivnit nejistoty prováděných měření. V tomto článku se zabýváme přímou metodou měření indexu lomu vzduchu, která je založena na měření rozdílu optických drah mezi vzduchem a vakuem uvnitř permanentně evakuované dvoukomorové kyvety pomocí kombinace laserové interferometrie a interferometrie nízké koherence.
Sinkholes that are often formed over shallow mining workings constitute a significant threat to buildings, infrastructure and – most of all – to the residents. These deformations often occur after a long time following the completion of mining works. A considerable number of sinkholes are formed above shallow headings due to the loss of bearing capacity of old wooden supports. Because of the above, the problem of predicting the formation of sinkholes gains significance. This paper presents the assumptions of Strzałkowski’s method of predicting discontinuous surface deformations (sinkholes). The deterministic model reflects the essence of the mechanism of destruction of the rock mass surrounding the void. The presented study case – another example of using the method for providing an ex post prognosis indicates its practical usability. The computer programme used in this paper is helpful to laborious calculations.
Photoinhibitory fluorescence quenching, qjjj, was detected in šitu in a montane spruce forest using a non-destructive chloropbyll fluorescence method combined with parallel sampling of light and temperature data. occuired as a common phenomenon in this type of ecosystem, altbougb low irradiances (LI) were tfae major factor limiting the growth. Under the prevailing LI photoinhibition was due to the suboptimal temperatures rather than irradiance. The found pattem of photoinhibitory fluorescence quenching is supposed to be characteristic of measuring sites in this montane region, where high irradiance (HT) is rare, but if it occurs, then it is along with a high temperature.