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1

Diversity of Ant Community in Ore Sedimentation Basin under Different Regimes of Reclamation

Dvořáčková M., Pech P., Prausová R., Horák J.

Polish Journal of Ecology

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2018

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Vol. 66, nr 2

139--152

EN

Post-industrial sites form a unique phenomenon in the landscape. They enable us to study the human-altered succession of communities. Regarding this, we studied an ant community in three types of habitats – reclamation and spontaneous succession in an ore basin together with unaltered surroundings in the Czech Republic. More than 30 years after being abandoned, the site with spontaneous succession was more species rich than the reclaimed one. Moreover, spontaneous succession created a habitat that was more similar regarding ant diversity to the unaltered surrounding environment than that after traditional reclamation. Ants dependent on tree vegetation were rather rare in both the reclaimed and spontaneous succession parts of the ore basin compared to the surrounding landscape. The relative abundance of socially parasitic ants increases in a gradient from the reclaimed basin, through the basin with spontaneous succession to the unaltered surroundings. Our study highlighted the fact that the formation of ant communities at post-industrial sites is clearly more complicated than for other arthropods, including related aculeate hymenopterans. The potential of both reclaimed and spontaneous succession basins for harbouring endangered species appeared to be lower for ants than for other taxa indicated by recent studies.

2

The Effect of Different Rates of Biochar and Biochar in Combination with N Fertilizer on the Parameters of Soil Organic Matter and Soil Structure

Juriga M., Šimanský V., Horák J., Kondrlová E., Igaz D., Polláková N., Buchkina N., Balashov E.

Journal of Ecological Engineering

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2018

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Vol. 19, nr 6

153--161

EN

Since biochar is considered to be a significant source of carbon, in this work we have evaluated the changes in soil organic matter (SOM) and soil structure due to application of biochar and biochar with N fertilization, and have considered the interrelationships between the SOM parameters and the soil structure. The soil samples were collected from Haplic Luvisol at the locality of Dolná Malanta (Slovakia) during 2017. The field experiment included three rates of biochar application (B0 – no biochar, B10 – biochar at the rate of 10 t ha-1, B20 – biochar at the rate of 20 t ha-1) and three levels of N fertilization (N0 – no nitrogen, N160 – nitrogen at the rate of 160 kg ha-1, N240 – nitrogen at the rate of 240 kg ha-1). The rate of biochar at 20 t ha-1 caused an increase in the organic carbon (Corg) content. The combination of both rates of biochar with 160 and 240 kg N ha-1 also caused an increase in Corg. In the case of B20 the extractability of humic substances carbon (CHS) was 17.79% lower than at B0. A significant drop was also observed in the values of the extraction of humic acids carbon (CHA) and fulvic acids carbon (CFA) after the addition of biochar at a dose of 20 t ha-1 with 160 kg N ha-1. However, both rates of biochar had a significant effect at 240 kg N ha-1. After application of 20 t ha-1 of biochar the content of water-stable macro-aggregates (WSAma) significantly increased compared to control. This rate of biochar also increased the mean weight diameter (MWDW) and the index of water-stable aggregates (Sw) and decreased the coefficient of vulnerability (Kv). The biochar at a rate of 20 t ha-1 with 240 kg N ha-1 the value of MWDW increased and value of Kv decreased significantly. The contents of Corg and CL correlated positively with WSAma, MWDW and Sw and negatively with WSAmi and Kv. The extraction of CHA and CFA was in negative relationship with MWDW. We conclude that the application of biochar and biochar combined with N fertilizer had a positive influence on SOM and soil structure.

3

Possible Suppression of Magnetorotational Instability by Rapid Radial Flow

Abramowicz M. A., Horák J., Kluźniak W.

Acta Astronomica

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2013

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Vol. 63, No. 2

267--273

EN

By investigating the magnetorotational instability (MRI) in a region of rapidly varying accretion-disk thickness, e.g., in the ISCO region, we find a limit to the applicability of a recent finding by Balbus (2012) that the MRI is present also in the region of Rayleigh-unstable flow.

4

Determination of kinetic parameters of pulverized coal in drop tube test facility

Hopan F., Mikulová Z., Horák J.

Rynek Energii

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2012

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Nr 6

113--118

EN

Thermokinetic description of coal combustion is a very complex process and its detailed description is very difficult due to composition of coal and different process conditions. The Drop Tube Test Facility enables observation of thermokinetics of heterogeneous oxidation of pulverized coal and subsequent determination of kinetic parameters from the experimental results. From this point of view, quite simple relations can be calculated for a specific type of fuel. These relations are suitable for proposals of new modern construction of burners and boilers.

PL

Kinetyczny opis spalania pyłu węglowego z powietrzem jest skomplikowanym procesem. Dokładny opis matematyczny owego procesu wymaga szczegółowych analiz. Obecny stan wiedzy na ten temat pozwala nam precyzyjnie opisać kinetykę prostych reakcji chemicznych, na przykład jednorodnego spalania mieszaniny paliwa wraz z utleniaczem. W przypadku utleniania złożonej mieszaniny substancji węglowych o różnym składzie, proces ten jest bardzo trudny do dokładnego opisania. Specjalne urządzenie zwane „rurą opadową” pozwala na badanie heterogenicznego utleniania sproszkowanego paliwa, a następnie pozwala określić parametry kinetyczne z otrzymanych danych pomiarowych. Z ustalania przebiegu wypalania paliwa możliwe jest określenie stosunkowo prostych relacji empirycznych, ważnych dla konkretnego typu sproszkowanego paliwa, które następnie mogą zostać użyte jako jedno z założeń przy projektowaniu konstrukcji nowoczesnych korpusów palników oraz kotłów.

5

Nanoparticles emission during brown coal briquettes combustion in small output furnaces

Danihelka P., Hase V., Mička V., Kubesa P., Krpec K., Horák J., Lach K.

Rynek Energii

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2011

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Nr 5

145-149

EN

The combustion of solid fuels is a significant source of air pollution and together with knowledge progression, new important pollutants have been discovered and studied. Nowadays, the growing attention is paid to nanoparticles and their health effects in all branches where they are produced including combustion. To contribute to this research, the measurement of nanoparticles emissions from brown coal briquettes combustion in a small output under-fire boiler was performed in various stages of combustion. Sampling train problems have been overcome, most of them linked to high particles concentration, condensation of water and nanoparticles adsorption at sampling train walls. Nevertheless, some difficulties persist. Nanoparticles number distribution was measured in the range 5 nm to 250 nm by FMPS spectrometer. Results show that the prevailing part of nanoparticles corresponds to the range from 6 to 100 nm, the distribution is multimodal (generally bimodal) and both total concentration and distribution vary during different stages of combustion. The highest nanoparticles concentration was observed during stabilization period of burning where two maxims about 15 nm and about 35 nm were found. A noticeable change was observed at the end of burning - total particle concentration decreased almost to a half, ultrafine particles maximum (size 10 - 20 nm) found in the earlier phase almost disappeared and only one maximum (around 35 nm) remained in the histogram. This implies the change in nanoparticles formation mechanism.

PL

Spalanie paliw stałych stanowi znaczące źródło zanieczyszczenia powietrza Wraz z postępem nauki, odkrywane i badane są natomiast nowe, istotne zanieczyszczenia. Obecnie coraz większą uwagę we wszystkich gałęziach przemysłu poświęca się nanocząstkom, analizom podlega również ich wpływ na zdrowie. Powstają one zarówno w procesie spalania w energetyce zawodowej jak i komunalnej. Aby przyczynić się do rozwoju tych badań, zostały przeprowadzone pomiary emisji nanocząsteczek ze spalania brykiet z węgla brunatnego w małym kominku domowym na różnych etapach procesu spalania. W instalacji poboru próbek napotkano na problemy związane z wysokim stężeniem nanocząstek, kondensowaniem pary wodnej oraz adsorpcją nanocząsteczek na ściankach rurek. Owe problemy zostały jednak częściowo wyeliminowane. Rozkład nanocząstek został zmierzony za pomocą spektrometru FMPS o zakresie od 5 do 250 nm. Wyniki otrzymane z przeprowadzonego procesu spalania brykiet z węgla brunatnego w kominku z dolnym spalaniem pokazują, iż powstające nanocząsteczki mieściły się w zakresie od 6 do 100 nm. Charakteryzowała je multimodalność (a nawet bi-modalność), zmienne dla różnych faz procesu spalania. Najwyższe stężenia pyłowych nanocząstek zostały zaobserwowane podczas stabilnej fazy procesu spalania, gdzie zmierzono dwie najwyższe wartości - 15 nm i 35 nm. Zauważalne zmiany zaszły pod koniec procesu spalania. Całkowite stężenie cząstek spadło prawie o połowę, natomiast udział najdrobniejszej frakcji nanocząstek (10 - 20 nm) występujących we wcześniejszych fazach prawie zanikły. Pozostała jednak frakcja nanocząstek (ok. 35 nm) zarejestrowana podczas pomiarów. Spowodowało to zmianę w mechanizmie powstawania nanaocząstek.

6

Fine particle emissions from combustion of wood and lignite in small furnaces

Branc M., Horák J., Ochodek T.

Environment Protection Engineering

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2011

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Vol. 37, nr 2

123-132

EN

Assessment of household combustion emission was carried out based on data on meteorological conditions in heating season (outdoor temperature) and the emission factors. Available emission factors, both for various fuels and for various combustion devices differ markedly. The results of experimental determination of particle matter emissions, including dividing total suspended particulate matter into various fractions (PM10 and PM 2.5) have been presented in the paper. Various combustion devices to burn wood and lignite were used in experiments. Samples were taken in a dilution tunnel with the help of an impactor. It was found that specific emissions differ significantly during the combustion cycle. Compared to the used emission factors, differences are evident. It was found that TSP specific emissions depend mainly on the type of construction not its age.

7

Parameters of design and technical solutions of tiled stove

Petránková Ševčíková S., Koloničný J., Horák J.

Rynek Energii

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2010

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nr 5

130-134

EN

One of the most important properties of the tiled stove is their accumulative capacity. The accumulative capacity is given by more parameters, but most important are thermal-technical properties of ceramic materials. Ceramic materials are as the main element of tiled stove interior design; as well they make the overall exterior appearance. The constructional solution of fireplace and ducts configuration has influence beside technical parameters to whole shape and design of tiled stoves. Based on a detailed examination of constructional solutions and a series of executed tests were determining connection of numerous parameters. The main monitored parameters were beside the accumulative capacity the efficiency, emission characteristics and performance and dimensional characteristics.

PL

Jedną z głównych właściwości pieców kaflowych jest zdolność akumulacji ciepła. Zależy ona głównie od właściwości cieplnych i technicznych materiałów ceramicznych. Materiały zaś mają również istotną rolę w procesie projektowania. Autorzy zamieścili wyniki badań eksperymentalnych pieców kaflowych, które będą brane pod uwagę w dalszych pracach projektowych. Zwrócono szczególna uwagę na akumulację ciepła, efektywność procesu, emisję zanieczyszczeń do atmosfery i charakterystyki kierunkowe przekazywania ciepła.

8

On the Origin of Clustering of Frequency Ratios in the Atoll Source 4U 1636-53

Török G., Abramowicz M. A., Bakala P., Bursa M., Horák J., Rebusco P., Stuchlík Z.

Acta Astronomica

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2008

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Vol. 58, No. 2

113--119

EN

A long discussion has been devoted to the issue of clustering of the kHz quasi periodic oscillation (QPO) frequency ratios in neutron star sources. While the distribution of ratios inferred from an occurrence of a single QPO seems to be consistent with a random walk, the distribution based on simultaneous detections of both peaks indicates a preference of ratios of small integers. Based on the public RXTE data we further investigate this issue for the source 4U 1636-53. Quality factors and rms amplitudes of both the QPOs nearly equal at the points where the frequencies are commensurable, and where the twin QPO detections cluster. We discuss a connection of the clustering with the varying properties of the two QPO modes. Assuming approximate relations for the observed correlations of the QPO properties, we attempt to reproduce the frequency and ratio distributions using a simple model of a random-walk evolution along the observed frequency-frequency correlation. We obtain results which are in qualitative agreement with the observed distributions.

9

Distribution of Kilohertz QPO Frequencies and Their Ratios in the Atoll Source 4U 1636-53

Török G., Abramowicz M. A., Bakala P., Bursa M., Horák J., Kluźniak W., Rebusco P., Stuchlík Z.

Acta Astronomica

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2008

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Vol. 58, No. 1

15--21

EN

A recently published study on long term evolution of the frequencies of the kilohertz quasi-periodic oscillations (QPOs) in the atoll source 4U 1636-53 concluded that there is no preferred frequency ratio in a distribution of twin QPOs that was inferred from the distribution of a single frequency alone. However, we find that the distribution of the ratio of actually observed pairs of kHz QPO frequencies is peaked close to the 3/2 value, and possibly also close to the 5/4 ratio. To resolve the apparent contradiction between the two studies, we examine in detail the frequency distributions of the lower kHz QPO and the upper kHz QPO detected in our data set. We demonstrate that for each of the two kHz QPOs (the lower or the upper), the frequency distribution in all detections of a QPO differs from the distribution of frequency of the same QPO in the subset of observations where both the kHz QPOs are detected. We conclude that detections of individual QPOs alone should not be used for calculation of the distribution of the frequency ratios.

10

Modulation of the Neutron Star Boundary Layer Luminosity by Disk Oscillations

Abramowicz M. A., Horák J., Kluźniak W.

Acta Astronomica

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2007

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Vol. 57, No. 1

1--10

EN

Paczyński (1987) pointed out that any modulation of the rate at which mass is accreted by a neutron star from the innermost part of a relativistic accretion disk will lead to a modulation of the luminosity of the boundary layer. Following this reasoning, we demonstrate that variability of the boundary layer X-ray flux must necessarily show frequencies of certain global accretion disk oscillations. This theoretical paradigm - clock in the disk, modulation at the boundary layer - resolves one puzzling paradox in the neutron star quasi periodic oscillation (QPO) data.