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Open access

Wojciech Batko and Paweł Pawlik

Abstract

The acoustic climate assessment needed for the selection of solutions (technical, legal and organisational), which will help to minimise the acoustic hazards in the analysed areas, is realised on the basis of acoustic maps. The reference computational algorithms, assigned to them, require very thorough preparation of input data for the considered noise source model representing - in the best possible way - the acoustic climate. These input data are burdened with certain uncertainties in this class of computational tasks. The uncertainties are related to the problem of selecting proper argument values (from the interval of their possible variability) for the modelled processes. This situation has a direct influence on the uncertainty of acoustic maps.

The idea of applying the interval arithmetic for the assessment of acoustic models uncertainty is formulated in this paper. The computational formalism assigned to the interval arithmetic was discussed. The rules of interval estimations for the model solutions determining the sound level distribution around the analysed noise source - caused by possible errors in the input data - were presented. The application of this formalism was illustrated in uncertainty assessments of modelling acoustic influences of the railway noise linear source on the environment.

Open access

Wojciech Batko, Paweł Pawlik and Grazyna Wszołek

Abstract

Acoustic barriers are assigned to the respective categories of sound absorbing properties on the basis of a single-number sound absorption evaluation index. Categories of absorbing properties play a significant role in selecting the barrier type for the given localisation. The estimation of the single-number sound absorption evaluation index is performed, among others, by means of measuring the sound absorption coefficient of the analysed acoustic barrier sample in the reverberation chamber. The sensitivity analysis of the determination of the single-number sound absorption evaluation index was performed in this work. The estimation of the input parameters uncertainty contribution to the expanded uncertainty of the sound absorption evaluation index, was done first. The Monte Carlo method and the reduction interval arithmetic were used for this aim. The relative sensitivity coefficients were determined by means of the author’s method based on the interval arithmetic. These coefficients contain information concerning the quantitative influence of the given input value on the final result.

Open access

Paweł Oglęcki and Artur Radecki-Pawlik

Abstract

The macroinvertebrate fauna of the Młynne stream (Polish Carpathians) in the aspect of the bed load transport and water quality. The qualitative composition of the bottom sediments and the bed load and suspended load transport along the mountain stream were presented. The studies were carried on the Młynne stream in Gorce (Polish Carpathians). The streams flows partially in the natural river-bed and partially in the regulated with rapids. The stream bed load is accumulated in the reservoir up to the check dam and is qualitatively different from the load deposited at the bars. The taxonomic richness of the Młynne stream is a little bigger compared with the other investigated mountain and sub-mountain streams, but lesser compared with bigger rivers. The number of taxa on the natural reaches is more than double than on the regulated ones, with more taxa of high environmental demands and high values of the BMWP-PL index. The paper brings up the question of the environmental friendly technical solutions in different human activities in the sub-mountain and mountain river valleys, advantageous for humans and the river biological diversity (or resistance for negative environmental factors) as well.

Open access

Tomasz Korbiel, Bartłomiej Stepien, Wojciech Batko, Robert Baranski, Dominik Mleczko, Paweł Pawlik and Jedrzej Blaut

Abstract

The civilisation progress has caused noise to become one of essential pathogenic and life comfort decreasing factors. There are several legal regulations aimed at controlling the noise influence on humans. Assessment of the twenty-four-hour influence of noises in various environments constitutes an essential problem. The answer can be supplied by 24-hour monitoring of the sound pressure. This paper is an attempt to learn the real loading of humans by noises. A personal noise indicator was used in measurements. The human 24-hour activity was divided into cycles allowing to model noise hazards. The collected data, even though they did not signal exceeding of individual standards, in the 24-hour period indicated the essential noise influence. These results indicate the need of investigations to recognise the 24-hour noise load of a human, with taking into account various forms of their activity and the need of rest.

Open access

Magdalena M. Mrokowska, Paweł M. Rowiński, Leszek Książek, Andrzej Strużyński, Maciej Wyrębek and Artur Radecki-Pawlik

Abstract

Two sets of triangular hydrographs were generated in a 12-m-long laboratory flume for two sets of initial bed conditions: intact and water-worked gravel bed. Flowrate ranging from 0.0013 m3 s-1 to 0.0456 m3 s-1, water level ranging from 0.02 m to 0.11 m, and cumulative mass of transported sediment ranging from 4.5 kg to 14.2 kg were measured. Then, bedload transport rate, water surface slope, bed shear stress, and stream power were evaluated. The results indicated the impact of initial bed conditions and flow unsteadiness on bedload transport rate and total sediment yield. Difference in ratio between the amount of supplied sediment and total sediment yield for tests with different initial conditions was observed. Bedload rate, bed shear stress, and stream power demonstrated clock-wise hysteretic relation with flowrate. The study revealed practical aspects of experimental design, performance, and data analysis. Water surface slope evaluation based on spatial water depth data was discussed. It was shown that for certain conditions stream power was more adequate for the analysis of sediment transport dynamics than the bed shear stress. The relations between bedload transport dynamics, and flow and sediment parameters obtained by dimensional and multiple regression analysis were presented.