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O adaptivních časových krocích pro počítačovou simulaci přesunů tepla a hmoty při vakuovém vymrazování
Georgiev, K. ; Kosturski, N. ; Margenov, S. ; Starý, Jiří
The work is motivated by the problem of freeze-drying, which is a process of dehydrating frozen materials by sublimation under high vacuum. Especially, it concerns the mathematical modelling and computer simulation of the heat and mass transfer with the core in solving the time-dependent nonlinear partial differential equation of parabolic type. Instead of an uniform discretization of the considered time interval, an adaptive time stepping procedure is applied in an effort to optimize the whole simulation. The procedure is based on the local comparison of the Crank-Nicholson and backward Euler time steps. The results of numerical experiments performed on a selected real-life problem are included.
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Modelování THM procesů v horninách
Blaheta, Radim ; Kohut, Roman ; Neytcheva, M. ; Starý, Jiří
This paper is devoted to medelling thermal (T), hydraulic (H) and mechanical (M) processes in rocks.These physical processes seem to be most important ones for many engineering applications ranging from the classical mining, tunelling and underground constructions to new geotechnologies of waste disposal or geothermal anergy utilization.
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Paralelní počítání termoelastického modelu KBS
Starý, Jiří ; Kohut, Roman
The paper describes numerical experiments with a finite element solution of the thermo-elasticity model KBS. Especially, it is devoted to the parallel computing of nonstacionary heat conduction problem, when the linear systems arising in each time step are solved by the overlapping domain decomposition method.
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Aplikace paralelních výpočtů v geotechnice
Starý, Jiří ; Blaheta, Radim ; Kohut, Roman
The paper concerns the mathematical modelling of elasticity and thermo-elasticity problems arising from two challenging geotechnical tasks. The modelling leads to solving the sequence of large-scale systems of linear equations. For such systems, we use high performance iterative solvers being able to run on parallel computers.
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Vliv různých travních směsí na společenstva pancířníků (Acari: Oribatida) v iniciálních sukcesních stádiích během obnovy květnatých luk
Starý, Josef
Altogether 400 quantitative soil samples were taken from 8 stationary plots in the localities Výzkum and Čertoryje in the Bílé Karpaty Mts. during the years 1999-2002. The present study is based on material of 10563 oribatid specimens belonging to 62 oribatid species. The lowest species richness and mean abundance were recorded on the plot with agricultural management.The highest mean abundance was found on the old sub-xerothermic meadow in Čertoryje. The eurytopic species .i.Scheloribates laevigatus./i. and .i.Tectocepheus velatus./i. as well as the heliophilous .i.Punctoribates punctum./i. were eudominant in all studied plots. These eudominant species were complemented by the dominant and recedent eurytopic species .i.Microppia minus, Hemileius initialis, Achipteria coleoptrata./i. and .i.Medioppia subpectimata./i.. The rare xerophilous species .i.Lucoppia burrowsi./i. was found in the plots sowed by different grass mixtures and in the fallow.
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Dlouhodobý půdně-zoologický výzkum v CHKO Jeseníky
Rusek, Josef ; Starý, Josef ; Tajovský, Karel ; Pižl, Václav
CHKO Jeseníky a její přírodní rezervace představují z hlediska půdně-zoologického velmi cennou oblast, v níž se na malém území setkávají arkto-alpínské elementy s teplomilnými prvky na jedné straně a karpatské elementy se sudetskými na straně druhé a seskupují se do charakteristických a bohatých společenstev v závislosti na vysoké ekosystémové diversifikací území. Půdní fauna je vůdčím půdotvorným činitelem a podmiňuje i zdejší výskyt reliktních tundrových půd. Management chráněných území musí vycházet z komplexních vědeckých poznatků a ekosystémových přístupů a půda musí být jejich nedílnou součástí.
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Změny ve společenstvech půdní mikroflóry a mesofauny během rozkladu listového opadu ve dvou vegetačních zónách - litter bag experiment
Jirout, Jiří ; Petrásek, Jiří ; Čápová, Lenka ; Farská, Jitka ; Jínová, Kristýna ; Rusek, Josef ; Krištůfek, Václav ; Elhottová, Dana ; Starý, Josef ; Nováková, Alena
The hypothesis, whether autochthonous species of soil biota are able to decompose litter from lower vegetation zones in higher zones, was tested by field trial. Litterbags with litter of beech (.i.Fagus sylvatica./i. L.) and/or oak (.i.Quercus robur./i. L.) were exposed in beech and spruce forest on the mountain Kleť (Protected Landscape Area Blanský les). Litterbags layout simulated vegetation zones shift to the higher altitude induced by global warming. There were used litterbags with three different mesh size (42 µm, 0,5 mm, 2 mm) for exclusion of certain parts of edaphon. Several changes of soil bacteria and micromycetes, oribatid mites, springtails and gamasid mites were studied during two years of exposition. There were exposed 480 litterbags at the start of the experiment (November 2002). After 2, 4, 6, 12, 24 months of exposition parts of all litterbags were recovered. Immediately after the sampling litter pH(KCl), moisture and mass loss were measured.
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