The minimum size of the bootstrap algorithm input parameters have been determined for estimation of long-term indicators of road traffic noise. Two independent simulation experiments have been performed for that purpose. The first experiment served to determine the impact of original random sample size, and the second to determine the impact of number of the bootstrap replications on the accuracy and uncertainty of estimation of long-term noise indicators. The inference has been carried out based on results of non-parametric statistical test at significance level α = 0.05. The simulation experiments have shown that estimation of long-term noise indicators with uncertainty below ±1 dB(A) requires all-day noise measurements during three randomly selected days during the year in a dense urban development. The maximum size of original random sample should not exceed n = 50 elements. The minimum number of bootstrap replications necessary for estimation should be B = 5000. The data used to the simulation experiments and carry out the analysis were results of continuous monitoring of road traffic noise recorded in 2009 in one of the main arteries of Krakow in Poland.

The corrosion resistance Cr₃C₂-25%NiCr and Ni-20%Cr coatings were deposited on the alloy A-286 by high-velocity oxy-fuel (HVOF) coating, and the high-temperature corrosion features were evaluated at 700 and 850°C in Na₂SO₄-5%NaCl-7.5%NaVO₃ atmosphere. Deposited coatings are dense and well-adherent to the substrate. A scanning electron microscope (SEM) is used to analyze the structure of the corroded samples. Results showed that Cr₃C₂ -25%NiCr coating provides better resistance to corrosion at 700°C, which is attributed to the protective Cr₂O₃ development. The coated metal was exposed at 850°C, and a higher corrosion rate was observed compared to 700°C, indicating that the temperature influenced the oxidation rate. The coating failure (crack) was noticed on the Cr₃C₂-25%NiCr coated surface when exposed at 850°C, and no damages are in the Ni-20%Cr coating.