An Algorithm for Investigating the Structure of Material Surfaces

The aim of this paper is to summarize the algorithm and the experience that have been achieved in the investigation of grain structure of surfaces of certain materials, particularly from samples of gold. The main parts of the algorithm to be discussed are:1. acquisition of input data,2. localization of grain region,3. representation of grain size,4. representation of outputs (postprocessing)

Application of Discrete Element Methods to the Problem of Rock Bumps

This paper is a continuation of a previous paper by the authors. Applications of two discrete element methods (DEM) to several fields of geotechnics are discussed. The free hexagon element method is considered a powerful discrete element method, and is widely used in mechanics of granular media. It substitutes the methods for solving continuum problems. In order to complete the study, other discrete element methods are discussed. The second method starts with the classical particle flow code (PFC, which uses dynamic equilibrium), but we apply static equilibrium in our case. The second method is called the static particle flow code (SPFC). The numerical experiences and comparison with experimental results from scaled models are discussed

Příprava pedagogů na realizaci prevence na základních školách

Autor ve svém příspěvku sleduje roli školy v systému prevence, popisuje cíle prevence (objectives of prevention), vznik Minimálních preventivních programů (minimal preventative programmes) a problematiku role učitele – školního metodika prevence (school preventive worker)

Diagnostics of hydraulic fluids used in aviation

ArticleDiagnostics is a maintenance industry that monitors performance, parameters, and follow – up. Diagnosing hydraulic fluids means comparing the parameters of the used hydr aulic fluid sample to the parameters of the clean fluid. It is also essentia l to monitor the limit values either by the aircraft manufacturer or by the manufacturer of the hydraulic fluid. This means that the manufacturer recommends the limitations of the liquid parameters. The measurements of the fluid samples give an overview of the liquid quality. Most businesses focus on so – called proactive maintenance. The main senses and objectives of proactive maintenance are: lubricant sample analysis, lubricant sta tus, machine status, next step recommendation, database saving and trend analysis. This article focuses on the quality of hydraulic fluid focused in aviation. The aim of the article was to determine the properties of the hydraulic fluid used in the A320 ai rcraft family, determine the interval of its exchange. Monitoring the state of the hydraulic fluid could contribute to the timely detection of the problem, thus avoiding a failure of the device or the system as a whole. The tracking proposal is an integral part of this article

Energy analysis of hydrogen as a fuel in the Czech Republic

ArticleThe concept of ‘hydrogen economy’ dates back to the 1970s. It was first introduced as s response to the first oil crisis. In the context of the hydrogen economy, it is important to calculate how much hydrogen would be needed to power all motor vehicles in the Czech Republic. This is main topics of this paper. To calculate the amount of hydrogen, we used two different methods. One is based on thermodynamic laws and the other on normal operating conditions. Both approaches yielded comparable results. It was found out that even with the use of all the electricity produced in the Czech Republic in 2016, we would not be able to cover the amount of energy that is required for production. It would cover only 75% resp. 76% depending on the calculation method used. Eventually, the Czech Republic could buy necessary amount of hydrogen and it would cost between 11 and 29 billion euros which is between 6% and 16% of GDP of the Czech Republic. In the calculations, authors found out that most fuel is burnt in the passenger cars. Therefore, we made a sensitivity analysis to find out how much our results would differ if fuel consumption changed. It turns out that with an increase in consumption of 1l per 100 km, hydrogen production coverage will decrease by about 4% (again with the use of all electricity produced in the Czech Republic)

Romanticism and Periodisation: A Roundtable

"‘Eternity is in love with the productions of time’. This original edited volume takes William Blake’s aphorism as a basis to explore how British Romantic literature creates its own sense of time. It considers Romantic poetry as embedded in and reflecting on the march of time, regarding it not merely as a reaction to the course of events between the late-eighteenth and mid-nineteenth centuries, but also as a form of creative engagement with history in the making. The authors offer a comprehensive overview of the question of time from a literary perspective, applying a diverse range of critical approaches to Romantic authors from William Blake and Percy Shelley to John Clare and Samuel Rodgers. Close readings uncover fresh insights into these authors and their works, including Frankenstein, the most familiar of Romantic texts. Revising current thinking about periodisation, the authors explore how the Romantic poetics of time bears witness to the ruptures and dislocations at work within chronological time. They consider an array of topics, such as ecological time, futurity, operatic time, or the a-temporality of Venice. As well as surveying the Romantic canon’s evolution over time, these essays approach it as a phenomenon unfolding across national borders. Romantic authors are compared with American or European counterparts including Beethoven, Irving, Nietzsche and Beckett. Romanticism and Time will be of great value to literary scholars and students working in Romantic Studies. It will be of further interest to philosophers and historians working on the connections between philosophy, history and literature during the nineteenth century.

Rufous Common Cuckoo chicks are not always female

This is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this recordThe Common Cuckoo (hereafter Cuckoo) shows two adult plumage morphs—adult male plumage is grey and adult females are either grey or, less frequently, rufous. The situation is less clear in juveniles, as both sexes exhibit variable proportions of grey and rufous colour. We thus describe the patterns related to sex-specific plumage colour variation in a central European Cuckoo population. We genetically determined the sex of 91 Cuckoo chicks and using visual classification of photographs we scored juvenile plumage colouration of individual chicks into five classes based upon the increasing proportion of rufous colour on feathers. To verify these scores, we sampled chick feathers and quantified the proportion of rufous colour of individual feathers by digital image analysis. We found that juvenile females had a higher proportion of rufous colour of feathers than juvenile males. However, the difference was marginally non-significant based on visual inspection alone, and some male chicks even showed intensively rufous plumage like those of juvenile females. In contrast, we captured only grey adult males (n = 37), while five out of 20 adult females were rufous. The rufous colour of Cuckoo feathers considerably differed from the grey colour and the difference seemed to be larger in adults than in juveniles. We show that chicks, unlike adult females, cannot be visually assigned to either of the adult morphs. Therefore, we encourage further investigation of Cuckoo plumage colouration across the species’ range to examine the process of plumage maturation. A detailed genetic analysis is necessary to understand the origin of Cuckoo feather colouration.This study was supported by the Czech Science Foundation (project 17-12262S) and by the Institutional Research Plan (RVO: 68081766)

Permutation Entropy and Signal Energy Increase the Accuracy of Neuropathic Change Detection in Needle EMG

Background and Objective. Needle electromyography can be used to detect the number of changes and morphological changes in motor unit potentials of patients with axonal neuropathy. General mathematical methods of pattern recognition and signal analysis were applied to recognize neuropathic changes. This study validates the possibility of extending and refining turns-amplitude analysis using permutation entropy and signal energy. Methods. In this study, we examined needle electromyography in 40 neuropathic individuals and 40 controls. The number of turns, amplitude between turns, signal energy, and “permutation entropy” were used as features for support vector machine classification. Results. The obtained results proved the superior classification performance of the combinations of all of the above-mentioned features compared to the combinations of fewer features. The lowest accuracy from the tested combinations of features had peak-ratio analysis. Conclusion. Using the combination of permutation entropy with signal energy, number of turns and mean amplitude in SVM classification can be used to refine the diagnosis of polyneuropathies examined by needle electromyography

Raman and Computational Study on the Adsorption of Xanthine on Silver Nanocolloids

Xanthine is a nucleobase, deriving from adenine and guanine by deamination and oxidation processes, which may deposit in the human body causing diseases, similar to uric acid. Here, we have investigated the adsorption of xanthine on silver colloidal nanoparticles by means of surface-enhanced Raman scattering (SERS) with an exciting radiation in the near-infrared spectral region, where interference due to fluorescence does not occur, along with density functional theory calculations of molecule/metal model systems. By adopting a combined experimental and computational approach, we have identified the "marker" SERS bands of xanthine and the tautomer that preferentially binds the silver particles, as well as the molecular group involved in the interaction with metal. This investigation allows using the FT-SERS spectroscopy for biosensory and diagnostic purposes in body fluids, detecting abnormal levels of xanthine, and preventing metabolic diseases