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Number of found documents: 14706
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Spherical basis function approximation with particular trend functions
Segeth, Karel
2023 - English
The paper is concerned with the measurement of scalar physical quantities at nodes on the $(d-1)$-dimensional unit sphere surface in the hbox{$d$-dimensional} Euclidean space and the spherical RBF interpolation of the data obtained. In particular, we consider $d=3$. We employ an inverse multiquadric as the radial basis function and the corresponding trend is a polynomial of degree 2 defined in Cartesian coordinates. We prove the existence of the interpolation formula of the type considered. The formula can be useful in the interpretation of many physical measurements. We show an example concerned with the measurement of anisotropy of magnetic susceptibility having extensive applications in geosciences and present numerical difficulties connected with the high condition number of the matrix of the system defining the interpolation. Keywords: spherical interpolation; spherical radial basis function; inverse multiquadric Available in digital repository of the ASCR
Spherical basis function approximation with particular trend functions

The paper is concerned with the measurement of scalar physical quantities at nodes on the $(d-1)$-dimensional unit sphere surface in the hbox{$d$-dimensional} Euclidean space and the spherical RBF ...

Segeth, Karel
Matematický ústav, 2023

Semantic segmentation using support vector machine classifier
Pecha, Marek; Langford, Z.; Horák, David; Tran Mills, R.
2023 - English
This paper deals with wildfire identification in the Alaska regions as a semantic segmentation task using support vector machine classifiers. Instead of colour information represented by means of BGR channels, we proceed with a normalized reflectance over 152 days so that such time series is assigned to each pixel. We compare models associated with $\mathcal{l}1$-loss and $\mathcal{l}2$-loss functions and stopping criteria based on a projected gradient and duality gap in the presented benchmarks. Keywords: wildfire identification; semantic segmentation; support vector machines; distributed training Fulltext is available at external website.
Semantic segmentation using support vector machine classifier

This paper deals with wildfire identification in the Alaska regions as a semantic segmentation task using support vector machine classifiers. Instead of colour information represented by means of BGR ...

Pecha, Marek; Langford, Z.; Horák, David; Tran Mills, R.
Ústav geoniky, 2023

The long-term impact of energy poverty and its mitigation on educational attainment: evidence from China
Martirosyan, Yervand
2023 - English
Existing studies demonstrate the short-run connection between environmental conditions and academic performance. However, the long-term effects of exposure to adverse living conditions on academic achievement remain underexplored. This study investigates the long-term impact of energy poverty, and policy interventions aimed at alleviating it, on the academic performance of Chinese schoolchildren starting from infancy. It specifically utilizes the Huai River Policy, which provides free winter heating exclusively to northern regions in China but not to adjacent southern regions. My findings suggest a significant positive influence of winter heating on schoolchildren’s academic performance, with a more pronounced effect for children born during winter months. The insights gained from this research could inform policy debates to enhance educational outcomes and human well-being.\n Keywords: energy poverty; academic performance; climate Fulltext is available at external website.
The long-term impact of energy poverty and its mitigation on educational attainment: evidence from China

Existing studies demonstrate the short-run connection between environmental conditions and academic performance. However, the long-term effects of exposure to adverse living conditions on academic ...

Martirosyan, Yervand
Národohospodářský ústav, 2023

Caves in Bohemia et Moravia Subterranea by Mauritius Vogt (1669–1730)
Rychnová, L.; Vokurka, Michal
2023 - English
The Manuscript Bohemia et Moravia Subterranea (1729) by Mauritius Vogt reflects the subterranean landscapes and underground spaces based on Athanasius Kircher’s theories. The paper analyses the application of Kirchers’s terminology to the natural phenomena from Bohemia and Moravia. Further, we focused on how Vogt worked with his sources – how far he relied on literature, correspondence, or personal experience. Keywords: Mauritius Vogt; caves; subterranean; underground; early modern period Available at various institutes of the ASCR
Caves in Bohemia et Moravia Subterranea by Mauritius Vogt (1669–1730)

The Manuscript Bohemia et Moravia Subterranea (1729) by Mauritius Vogt reflects the subterranean landscapes and underground spaces based on Athanasius Kircher’s theories. The paper analyses the ...

Rychnová, L.; Vokurka, Michal
Historický ústav, 2023

Hazardous components: A case study in textile waste management
Shtukaturova, Anastasia
2023 - English
Textile waste, a problem that has been somewhat overlooked for many years, is now coming to the fore.1 The textile value chain is long\nand complex, with over 8000 chemicals used in different manufacturing processes.2 A wide variety of chemicals are used in the manufacture of textile products for the improvement of essential properties and performance of textiles. Chemicals used in textiles significantly improve their quality and appearance. However, the harmful effects of these chemicals can occur at various stages of textile production and processing, such as dyeing, printing and finishing, as well as during use by consumers and at the end-of-life stage.3 There is a lack of safety information on the presence and use of all of these chemicals in consumer products. Keywords: textile waste; waste management; chemicals Available in a digital repository NRGL
Hazardous components: A case study in textile waste management

Textile waste, a problem that has been somewhat overlooked for many years, is now coming to the fore.1 The textile value chain is long\nand complex, with over 8000 chemicals used in different ...

Shtukaturova, Anastasia
Ústav chemických procesů, 2023

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

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