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3242. An evaluation of rolling contact fatigue of metallic materials using acoustic emission method
- Creator:
- Nohál, Libor and Mazal, Pavel
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- acoustic emission, rolling contact fatigue, defect, bearing, and pitting
- Language:
- English
- Description:
- A major cause of a surface damage of the contact loading machine components (bearings, gears, cams etc.) is the rolling contact fatigue, Various methods of condition monitoring are used to detect damage of these components or specimens in the industry or during testing in laboratories. In the past decades, the acoustic emission technique has been developed into useful condition monitoring method. This paper is focused on the testing of rolling contact fatigue of the metallic materials using acoustic emission method. The methodology of testing, experimenal test-rig and preliminary results, are presented in this paper. It can be concluded, that acoustic emission technique can be applied for more accurate rolling contact fatique evaluation of material. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3243. An Evaluation of Sgraffiti restorations in Lower Austria in relation to the restoration of a sgraffito decoration in Mannersdorf /
- Creator:
- Asimus, Sophia Raissa
- Type:
- text and studie
- Subject:
- Architektura, architektura, dekorace architektonické, péče památková, sgrafita, Rakousko, světové dějiny 1648-1789, and architektura, architekti
- Language:
- English
- Rights:
- unknown
3244. An evaluation of the levels of 25-hydroxyvitamin D3 and bone turnover markers in professional football players and in physically inactive men
- Creator:
- Krzysztof Solarz, Kopeć, A., Pietraszewska, J., Majda, F., Słowińska-Lisowska, M., and Mędraś, M.
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, vitamin D, fotbalisté, soccer players, bone turnover markers, football players, physical activity, 25(OH)D3, 14, and 612
- Language:
- English
- Description:
- Vitamin D is synthesised in the skin during exposure to sunlight and its fundamental roles are the regulation of calcium and phosphate metabolism and bone mineralisation. The aim of our study was to evaluate serum levels of 25-hydroxyvitamin D3 , PTH and bone turnover markers (P1NP, OC, β -CTx, OC/ β -CTx) and the intake of calcium and vitamin D in Polish Professional Football League (Ekstraklasa) players and in young men with a low level of physical activity. Fifty healthy men aged 19 to 34 years were included in the study. We showed that 25(OH)D3 and P1NP levels and OC/ β -CTx were higher in the group of professional football players than in the group of phys ically inactive men. The daily vitamin D and calcium intake in th e group of professional football players was also higher. We showed a significant relationship between 25(OH)D3 levels and body mass, body cell mass, total body water, fat-free mass, muscle mass, vitamin D and calcium intake. Optimum 25(OH)D3 levels were observed in a mere 16.7 % of the football players and vitamin D deficiency was observed in the physically inactive men. The level of physical activity, body composition, calcium and vitamin D intake and the duration of exposure to sunlight may significantly affect serum levels of 25(OH)D3 ., K. Solarz ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3245. An evaluation of velocity estimates with a correlated noise: case study of IGS ITRF2014 European stations
- Creator:
- Klos, Anna and Bogusz, Janusz
- Format:
- print, bez média, and svazek
- Type:
- article, články, journal articles, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, GPS sítě, GPS netwoks, ITRF2014, noise analysis, velocity, 7, and 551
- Language:
- English
- Description:
- The velocities of the Global Positioning System (GPS) stations are widely employed for numerous geodynamical studies. The aim of this paper is to investigate the reliability of station velocities and to draw reader’s attention that for proper estimates of velocity, we need to consider the optimal character of noise. We focus on a set of 115 European GPS stations which contributed to the newest release of the International Terrestrial Reference Frame (ITRF), i.e. ITRF2014. Based on stacked Power Spectral Densities (PSDs), we show that amplitudes o f seasonal signals are significant for nine harmonics of tropical year (365.25 days) and two harmonics of draconitic year (351.60 days). The amplitudes of tropical annual signal fall between 0.1-8.4 mm and are much higher for vertical component than for horizontal. Draconitic annual signal reaches the maximum amplitudes of 1.2 and 0.9 mm for North and East, respectively, whereas is slightly higher for the Up component with a maximum of 3.1 mm. We performed a noise analysis with Maximum Like lihood Estimation (MLE) and found that stations in Central and Northern Europe are characterized by spectral index between flicker and random-walk noise, while stations in Southern and Western Europe: between white and flicker noise. Both amplitudes and spectral indices of power-law noise show a spatial correlation for Up component. We compared the uncertainties of velocities derived in this study with a combination of power-law and white noises to the ones offici ally released in the ITRF2014 with a pure white noise. A ratio of the two estimates is larger than 10 for 13 % and 30 % of stations in horizontal and vertical direction, respectively with medians of 6 and 7. The large differences support the fact that at the velocity determination the proper noise characteristic should be taken into account to avoid any mislead interpretation., Anna Klos and Janusz Bogusz., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
3246. An evidence for regulatory cross-talk between aryl hydrocarbon receptor and glucocorticoid receptor in HepG2 cells
- Creator:
- Zdeněk Dvořák, Radim Vrzal, Petr Pávek, and Jitka Ulrichová
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Biochemie. Molekulární biologie. Biofyzika, biochemie, buněčné signály, membránové receptory, xenobiotika, glukokortikoidy, genetická informace, biochemistry, cell signals, membrane receptors, xenobiotics, glucocorticoids, genetic information, dioxin, transcriptional control, 2, and 577
- Language:
- English
- Description:
- Aryl hydrocarbon receptor (AhR) and glucocorticoid receptor (GR) play crucial role in the regulation of drug metabolizing enzymes and in many essential physiological processes. Cellular signaling by these receptors shares several functional and regulatory features. Here we investigated regulatory cross-talk between these two receptors. Human hepatoma cells (HepG2) were the model of choice. We analyzed the effects of dexamethasone (DEX) and dioxin (TCDD) on i) expression of AhR and GRα mRNAs; ii) levels of AhR and GR proteins; iii) transcriptional activities of AhR and GR in reporter assays; iv) 7-ethoxyresorufin-O-deethylase activity (EROD). We found that both DEX and TCDD affected AhR and GR mRNAs expression, proteins levels and transcriptional activities in HepG2 cells. These effects on cellular signaling by AhR and GR comprised up-/down-regulation of gene expression and ligand-dependent protein degradation. We conclude that interactive regulatory cross-talk between GR and AhR receptors in HepG2 cells defines possible implications in physiology and drug metabolism. Future research should be focused on the investigation of AhR-GR cross-talk in various normal human cells and tissues both in vitro and in vivo., Z. Dvořák, R. Vrzal, P. Pávek, J. Ulrichová., and Obsahuje bibliografii a bibliigrafické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3247. An evolutionary RBF network configuration using adaptive width adjustment based on vaccination
- Creator:
- Zang, Xiaogang, Gong, Xinbao, Ling, Xiaofeng, Chang, Cheng , and Tang , Bin
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Computational learning theory, evolutionary computation, neural networks, RBF networks, and vaccination operation
- Language:
- English
- Description:
- In this paper, a mechanism of adaptive width adjustment based on immunological vaccination is proposed for the evolutionary training of RBF neural networks. Inspired by the vaccination process of the natural immune system, the algorithm implements an individual-orientated adaptation of the width in training stages to optimize the potential solutions, therefore reinforces the evolutionary capability and efficiency. A two-layer genotype-coding scheme, which enables a simultaneous evolution of network structure and parameters, is presented to achieve a compact and consistent-in-form solution. The proposed learning strategy is tested on several benchmark problems and results demonstrate promise.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
3248. An evolutionary simulation of modularity emergence of genotype-phenotype mappings
- Creator:
- Kvasnička, Vladimír
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- modularity, genotype-phenotype mapping, evolutionary simulation, evolutionary algorithms, and evolvability
- Language:
- English
- Description:
- A novel rriethod that allows us to study the emergence of modularity for genotype-phenotype mapping in the course of Darwinian evolution is described. The evolutionary method used is based on cornposite chromosomes with two parts; One is a binary genotype whereas the other corresponds to the mapping of genes onto phenotype characters. For such generalized chromosomes the modularity is determined by the following intuitive way: The genes are divided into two subgroups; simultaneously with this decomposition also an accompanied decomposition of the set of phenotype characters is defined. We expect that for chromosomes with rnodular structures the genes frorn one group are rnapped onto characters from the respective group, an appearance of “crosslink” mappings is rnaximally suppressed. A fundamental question for the whole evolutionary biology (and also for evolutioriary algorithms and connectionist cognitive science) is the nature of mechanism of evolutionary emergence of modular structures. An idea of effective fitness is used in the presented explanatory simulations. It is based on the rnetaphor of Hinton and Nowlan theory of the Baldwin eífect, and was ušed as an effective idea for generalization of evolutionary algorithms. The effective fitness reflects not only a static concept of the phenotype, but also its ability to be adapted (learned) within a neighborhood of the respective chromosome. The chromosomes determined in the presented paper inay be understood as objects with the type of plasticity. The rnetaphor of the Baldwin effect (or effective fitness) applied to evolutionary algorithms offers an evolutionary tool that is potentially able to produce the emergence of modularity.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
3249. An example of a fiber in fibrations whose Serre spectral sequences collapse
- Creator:
- Yamaguchi, Toshihiro
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Sullivan minimal model, orientable fibration, TNCZ, and negative derivation
- Language:
- English
- Description:
- We give an example of a space $X$ with the property that every orientable fibration with the fiber $X$ is rationally totally non-cohomologous to zero, while there exists a nontrivial derivation of the rational cohomology of $X$ of negative degree.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
3250. An example of a positive semidefinite double sequence which is not a moment sequence
- Creator:
- Bisgaard, Torben Maack
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- double sequence, positive definite, and moment sequence
- Language:
- English
- Description:
- The first explicit example of a positive semidefinite double sequence which is not a moment sequence was given by Friedrich. We present an example with a simpler definition and more moderate growth as $(m, n) \rightarrow \infty $.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public