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Number of results: 16
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Abstract

Is it possible to revitalize Europe without external interference and a shift in the geopolitical situation outside the Continent? An answer to this question is here offered by Prof. Jan Zielonka, a political scientist analyzing change in Central and Eastern Europe and a lecturer at the European Studies Centre, St. Antony’s College, University of Oxford.
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Abstract

The Bulletin of the Polish Academy of Sciences: Technical Sciences (Bull.Pol. Ac.: Tech.) is published bimonthly by the Division IV Engineering Sciences of the Polish Academy of Sciences, since the beginning of the existence of the PAS in 1952. The journal is peer‐reviewed and is published both in printed and electronic form. It is established for the publication of original high quality papers from multidisciplinary Engineering sciences with the following topics preferred: Artificial and Computational Intelligence, Biomedical Engineering and Biotechnology, Civil Engineering, Control, Informatics and Robotics, Electronics, Telecommunication and Optoelectronics, Mechanical and Aeronautical Engineering, Thermodynamics, Material Science and Nanotechnology, Power Systems and Power Electronics. Journal Metrics: JCR Impact Factor 2018: 1.361, 5 Year Impact Factor: 1.323, SCImago Journal Rank (SJR) 2017: 0.319, Source Normalized Impact per Paper (SNIP) 2017: 1.005, CiteScore 2017: 1.27, The Polish Ministry of Science and Higher Education 2017: 25 points. Abbreviations/Acronym: Journal citation: Bull. Pol. Ac.: Tech., ISO: Bull. Pol. Acad. Sci.-Tech. Sci., JCR Abbrev: B POL ACAD SCI-TECH Acronym in the Editorial System: BPASTS.
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Abstract

The problem of mathematical modelling and indication of properties of a DIP has been investigated in this paper. The aim of this work is to aggregate the knowledge on a DIP modelling using the Euler-Lagrange formalism in the presence of external forces and friction. To indicate the main properties important for simulation, model parameters identification and control system synthesis, analytical and numerical tools have been used. The investigated properties include stability of equilibrium points, a chaos of dynamics and non-minimum phase behaviour around an upper position. The presented results refer to the model of a physical (constructed) DIP system.
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Abstract

The aim of this work was to identify concentration levels of different chemical forms of mercury (TGM, TPM) in the ambient air in selected areas of the Silesian Region, characterized by low and high mercury emission. Based on the obtained data TGM and TPM concentration levels were determined. The project also focused on determination of dry and wet deposition of mercury compounds. Data concerning TGM and TPM flux rates in the ambient air and data on mercury deposition were used to determine a deposition coefficient. The coefficient was calculated as a share of mercury deposition on the land surface (dry and wet) to the amount of this contaminant transported with loads of air in the form of TGM and TPM in a given measurement station. At both monitoring stations the deposition coefficient did not exceed 0.2 %. The idea of calculating the deposition coefficient based on the analysis of TGM and TPM flux rate is a new solution. The proposed deposition coefficient allows to quantify information on a selected contaminant concentration and its potential impact resulting from deposition. Further studies on the deposition coefficient may contribute to the development of methods for estimating the impact of contaminants contained in the ambient air on other environmental components based on the analyses of the contaminant flux rate.
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Abstract

In the paper, the authors discuss the construction of a model of an exemplary urban layout. Numerical simulation has been performed by means of a commercial software Fluent using two different turbulence models: the popular k-ε realizable one, and the Reynolds Stress Model (RSM), which is still being developed. The former is a 2-equations model, while the latter – is a RSM model – that consists of 7 equations. The studies have shown that, in this specific case, a more complex model of turbulence is not necessary. The results obtained with this model are not more accurate than the ones obtained using the RKE model. The model, scale 1:400, was tested in a wind tunnel. The pressure measurement near buildings, oil visualization and scour technique were undertaken and described accordingly. Measurements gave the quantitative and qualitative information describing the nature of the flow. Finally, the data were compared with the results of the experiments performed. The pressure coefficients resulting from the experiment were compared with the coefficients obtained from the numerical simulation. At the same time velocity maps and streamlines obtained from the calculations were combined with the results of the oil visualisation and scour technique.
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