The article analyzes museum representations of communism in Poland from the perspective of exhibition strategies influencing the public understanding of the past. Over the past forty years, Western museums have increasingly moved away from the affirmative model of presenting the past, dominating since the nineteenth century, towards critical paradigms and even those pro-moting social activism. The analysis of Polish exhibitions devoted to recent history carried out from this perspective allows us to reveal the functions fulfilled by museum institutions in the Polish social and political reality.

The small artificial surface defects in the coarse-grain steel are studied. The size of the used defects is smaller than the most relevant microstructural unit of steel, i.e. the average grain size. The samples of coarse-grain steel are prepared using a welding thermal-cycle simulator and a laboratory furnace. The defects are made by indenting with a Vickers pyramid. One of the final results of the defect making is the existence of local residual stresses. The influence of residual stresses on the crack initiation from those artificial defects is discussed in the article.