Properties and use of high-temperature biochar
Sedmihradská, Anežka
2023 - English Despite being a hot topic in environmental research, biochar and its properties have been mainly investigated from the perspectives of feedstock type and pyrolysis temperature. Few studies have explored the effect of particle size on biochar properties.Even when the effect of particle size on crop efficiency is recognized, there is a lack of corresponding data and analysis.2–7 Therefore, we thoroughly analyzed (proximate and ultimate analysis, SEM, XRD, Raman spectroscopy) four particle size fractions (< 0.5, 0.5–2, 2–5, > 5 mm) of high-temperature biochar from a gasification power plant, the sizes reflecting those of biochar actually used in agriculture. The < 0.5 mm fraction was significantly different in terms of carbon structure, and carbon and ash content. Consequently, pH, electric conductivity and heavy metal content also differed greatly. The corresponding results for the other particle fractions were broadly similar to each other. Interestingly, for all fractions, the porosity and H/C ratio were independent of particle size, meaning that, regardless of size, the investigated biochar fractions are equally stable in soil. The 0.5–2 mm fraction was then selected to be used in different industrial or agricultural processes such as the anaerobic digestion of wastewater or livestock feeding. The effect of biochar on these processes is currently under investigation, providing only initial data so far. Keywords: biochar; particle size on biochar; high-temperature biochar Available in a digital repository NRGL Properties and use of high-temperature biochar

Despite being a hot topic in environmental research, biochar and its properties have been mainly investigated from the perspectives of feedstock type and pyrolysis temperature. Few studies have ...

Sedmihradská, Anežka
Ústav chemických procesů, 2023

Vertical gradients of atmospheric aerosols chemical composition
Kovářík, Jiří
2023 - English The aim of this work is to obtain data on the chemical composition of aerosols at two heights (4–5 metres above ground and at 230 metres on the atmospheric tower’s measurement platform). The following and sampling techniques will be used: Aerosol Mass\nSpectrometry) – in combination with PMF (Positive Matrix Factorisation), Aerosol Chemical Speciation Monitor and Particle Into Liquid Sampler coupled with Ion Chromatography. Keywords: aerosols; analytical methods; chemical composition Available in a digital repository NRGL Vertical gradients of atmospheric aerosols chemical composition

The aim of this work is to obtain data on the chemical composition of aerosols at two heights (4–5 metres above ground and at 230 metres on the atmospheric tower’s measurement platform). The following ...

Kovářík, Jiří
Ústav chemických procesů, 2023

Liquid mixing time and gas holdup in a bubble column bioreactor
Terentyak, Mark
2023 - English The aim of the research is the experimental study of homogenisation and saeration in a bubble column in dependence on operational conditions and aspect ratio. Keywords: bubble column bioreactor; gas holdup; experiments Available in a digital repository NRGL Liquid mixing time and gas holdup in a bubble column bioreactor

The aim of the research is the experimental study of homogenisation and saeration in a bubble column in dependence on operational conditions and aspect ratio.

Terentyak, Mark
Ústav chemických procesů, 2023

A new blade cascade for flutter studies
Šnábl, Pavel; Pešek, Luděk; Procházka, Pavel P.; Skála, V.
2023 - English In this paper, a new blade cascade, developed in the Institute of Thermomechanics, is presented. The geometry of the cascade was modified so now the stall flutter can occur. It has some major construction improvements over the original cascade which now allow more precise and reliable measurements. The stability of the new blade cascade with five NACA 0010 profiles with rotational degree of freedom is assessed by Travelling Wave Mode approach and Aerodynamic Influence Coefficient approach. Keywords: blade cascade; stability; travelling wave mode; aerodynamic influence coefficient Available at various institutes of the ASCR A new blade cascade for flutter studies

In this paper, a new blade cascade, developed in the Institute of Thermomechanics, is presented. The geometry of the cascade was modified so now the stall flutter can occur. It has some major ...

Šnábl, Pavel; Pešek, Luděk; Procházka, Pavel P.; Skála, V.
Ústav termomechaniky, 2023

Kráľova Lehota. Paleomagnetic research. Report
Elbra, Tiiu; Schnabl, Petr; Aidona, E.; Kdýr, Šimon; Uçar, Hakan; Pruner, Petr; Benediková, L.
2023 - English Keywords: Archeological artefact; paleomagnetic dating; rock magnetism Available at various institutes of the ASCR Kráľova Lehota. Paleomagnetic research. Report

Elbra, Tiiu; Schnabl, Petr; Aidona, E.; Kdýr, Šimon; Uçar, Hakan; Pruner, Petr; Benediková, L.
Geologický ústav, 2023

PHYSICOCHEMICAL CHARACTERISTICS AND EVOLUTION OF AEROSOL FROM OPEN COMBUSTION OF BIOMASS DURING THE TRADITIONAL “BURNING OF THE WITCHES”
Mbengue, Saliou; Vodička, Petr; Komínková, Kateřina; Schwarz, Jaroslav; Zíková, Naděžda; Vítková, Gabriela; Windell, Laurence Christian; Suchánková, Lenka; Lhotka, Radek; Julaha, Kajal; Prokeš, Roman; Šmejkalová Holubová, A.; Ondráček, Jakub; Ždímal, Vladimír; Holoubek, Ivan
2023 - English Open biomass burning (OBB) is a major source releasing large quantities of gaseous and particulate pollutants into the atmosphere, with global, regional and local impacts on air quality, public health and climate (Andreae, 2019, Chen et al., 2017). OBB aerosols mainly consist of carbonaceous matter, and a considerable amount of inorganic salts, which present distinctly different optical properties (Chen et al., 2017, Reid et al., 2005). In this study, we investigate the influence of OBB during the traditional Burning of the Witches (BoW), referred to in Czech as “Pálení čarodějnic”, on the physico-chemical properties of atmospheric aerosols collected at the National Atmospheric Observatory Košetice (NAOK). The BoW is a centuries-old pagan tradition very popular in the Czech Republic. Today, it is celebrated during the night from April 30 to May 1 by lighting bonfires made of woodpiles with fake witches. Keywords: biomass burning; air pollution; size distribution; atmospheric ageing Available in digital repository of the ASCR PHYSICOCHEMICAL CHARACTERISTICS AND EVOLUTION OF AEROSOL FROM OPEN COMBUSTION OF BIOMASS DURING THE TRADITIONAL “BURNING OF THE WITCHES”

Open biomass burning (OBB) is a major source releasing large quantities of gaseous and particulate pollutants into the atmosphere, with global, regional and local impacts on air quality, public health ...

Mbengue, Saliou; Vodička, Petr; Komínková, Kateřina; Schwarz, Jaroslav; Zíková, Naděžda; Vítková, Gabriela; Windell, Laurence Christian; Suchánková, Lenka; Lhotka, Radek; Julaha, Kajal; Prokeš, Roman; Šmejkalová Holubová, A.; Ondráček, Jakub; Ždímal, Vladimír; Holoubek, Ivan
Ústav výzkumu globální změny , 2023

PM1 UNDER THE MICROSCOPE: MULTI-ANNUAL AEROSOL OPTICAL PROPERTIES AND SIZE DISTIRBUTION OBSERVATION AT PERI-URBAN ATMOSPHERIC SITE ATOLL
Suchánková, Lenka; Bourrianne, E.; De Fillipi, R.; De Brito, J. F.; Riffault, V.; Prokeš, Roman; Holoubek, Ivan; Ždímal, V.; Crumeyrolle, S.
2023 - English Atmospheric aerosols (AA) belong to short-lived climate forcers with high spatial and temporal variability. Although the radiative effects of AA are greatest on regional scales, changes in aerosol emissions can induce long-term global climate effects (Szopa et al., 2021). Thus, the measurement of aerosol properties is essential for better understanding of aerosol’s impact on health and climate. Although several international projects and platforms have been monitoring AA properties worldwide (GAW, WMO, ACTRIS, EMEP, EUCAARI, etc., Pandolfi et al., 2018), only PM10 or PM2.5 cutoff sizes have been used for measurements, and information about PM1 particles is missing. \nThe aim of this study is to present aerosol scattering properties with supporting data of absorption and particle number size distribution in PM1 in years 2018-2022 at peri-urban atmospheric site “Atmospheric Observations in LiLLE (ATOLL) in Lille, France. This study is the first to present results dedicated to aerosol scattering properties at this site. Keywords: pm1; scattering coefficient; nephelometer; fossil fuel and biomass burning contribution; aethalometer; smps Available in digital repository of the ASCR PM1 UNDER THE MICROSCOPE: MULTI-ANNUAL AEROSOL OPTICAL PROPERTIES AND SIZE DISTIRBUTION OBSERVATION AT PERI-URBAN ATMOSPHERIC SITE ATOLL

Atmospheric aerosols (AA) belong to short-lived climate forcers with high spatial and temporal variability. Although the radiative effects of AA are greatest on regional scales, changes in aerosol ...

Suchánková, Lenka; Bourrianne, E.; De Fillipi, R.; De Brito, J. F.; Riffault, V.; Prokeš, Roman; Holoubek, Ivan; Ždímal, V.; Crumeyrolle, S.
Ústav výzkumu globální změny , 2023

Thermal and creep analysis of VVER-1000 reactor pressure vessel at high temperatures caused by fuel melting during severe accident
Gabriel, Dušan; Gál, P.; Kotouč, M.; Dymáček, Petr; Masák, Jan; Kopačka, Ján
2023 - English Thermal and creep analysis of the VVER-1000 reactor pressure vessel (RPV) was performed at high temperatures caused by fuel melting during severe accident. First, the integral code ASTEC was applied simulating severe accident evolution since an initiating event up to a hypothetical radioactive release into the environment. The ASTEC outputs including the remaining RPV wall thickness, the heat flux achieved and the temperature profile in the ablated vessel wall served as boundary conditions for the consequent assessment of RPV integrity carried out with the aid of finite element method (FEM). The FEM analysis was performed including the creep behaviour of RPV material using a complex creep probabilistic exponential model with damage. The objective of the analysis was to computationally assess emergency condition and, on this basis, to propose a general methodology for evaluating the integrity of RPV at high temperatures due to fuel melting during severe accident. Keywords: integrity of reactor pressure vessel; severe accident; ASTEC; creep; FEM Fulltext is available at external website. Thermal and creep analysis of VVER-1000 reactor pressure vessel at high temperatures caused by fuel melting during severe accident

Thermal and creep analysis of the VVER-1000 reactor pressure vessel (RPV) was performed at high temperatures caused by fuel melting during severe accident. First, the integral code ASTEC was applied ...

Gabriel, Dušan; Gál, P.; Kotouč, M.; Dymáček, Petr; Masák, Jan; Kopačka, Ján
Ústav termomechaniky, 2023

Reduced modelling of aeroelastic instability in a turbine blade cascade
Pešek, Luděk; Šnábl, Pavel; Prasad, Chandra Shekhar
2023 - English The contribution deals with the first results on flutter instability of the linear cascade triggered by impulse excitation. Together with experimental results, numerical results obtained by reduced modelling of the cascade using van der Pol model of self-excitation are presented and discussed. Keywords: flutter; blade cascade; self-excitation; Van der Pol Available at various institutes of the ASCR Reduced modelling of aeroelastic instability in a turbine blade cascade

The contribution deals with the first results on flutter instability of the linear cascade triggered by impulse excitation. Together with experimental results, numerical results obtained by reduced ...

Pešek, Luděk; Šnábl, Pavel; Prasad, Chandra Shekhar
Ústav termomechaniky, 2023

Simulation of heterogeneously-catalyzed non-isothermal reactive flow in industrial packed beds
Hlavatý, Tomáš; Isoz, Martin; Khýr, M.
2023 - English Packed bed reactors are the most frequently used devices to perform heterogeneously catalyzed reactions on industrial scales. An industrial real-life heterogeneous catalysis is complex process that combines fully three-dimensional mass, momentum and energy transport on several scales. In the present work, we leverage our previously developed CFD solver for non-isothermal heterogeneously catalyzed reactive flow based on the finite volume method and couple it with our\nin-house DEM-based method for preparation of random packed beds. The resulting framework is verified in the simplified cases against available analytical solutions and correlations and is used to study an industrially-relevant case of ethylene oxychlorination performed in a tubular packed bed comprising CuCl2-coated catalyst carrying particles. In particular, we compare properties of three different industrially used catalyst carrying particles: Raschig rings, Reformax, and Wagon wheels Keywords: CFD; OpenFOAM; non-isothermal flow Available in a digital repository NRGL Simulation of heterogeneously-catalyzed non-isothermal reactive flow in industrial packed beds

Packed bed reactors are the most frequently used devices to perform heterogeneously catalyzed reactions on industrial scales. An industrial real-life heterogeneous catalysis is complex process that ...

Hlavatý, Tomáš; Isoz, Martin; Khýr, M.
Ústav termomechaniky, 2023