Selected scientific contacts of Jacek Hawranek and Jan Zygmunt with Professor Bogusław Wolniewicz in the period from the end of the 1980s to the beginning of the 21st century are presented in this essay. They concerned the algebraic aspects of the ontology of situations and from one moment – one only question that was posed by Wolniewicz in his note A question about join-semilattices (Bulletin of the Section of Logic, 19/3, 1990, pp. 108–108), and resulted in the Hawranek & Zygmunt paper Wokół pewnego zagadnienia z dziedziny półkrat górnych z jednością (“Some comments on a question about semilattices with unit”) (Acta Universitatis Wratislaviensis 1445, Logika 15 (1993), pp. 59–68) containing an answer to Wolniewicz’s question. The Hawranek & Zygmunt paper is reprinted below, and the essay might be also treated as a kind of an analytical and historical introduction to it. The story of contacts Wolniewicz – Hawranek & Zygmunt has been told with the help of the preserved correspondence between the three persons. In his letters Professor Wolniewicz appears as a passionate researcher, open to discussion, ready to share his research successes and difficulties with others.
Bogusław Wolniewicz, inspired by his formal ontology of situations, has put forward a question on semilattices with a unit (A question about joinsemilattices, Bulletin of the Section of Logic 19/3, 1990). The present paper is entirely devoted to this problem in the formulation given by Wolniewicz. First, the meaning of the question is analyzed and its lattice-theoretical and Boolean algebraic contents are exhibited. Second, set-theoretical and topological counterparts of the question are formulated and commented upon.
The paper presents a comparison of selected power technologies from the point of view of emissions of greenhouse gases. Such evaluation is most often based only on analysis of direct emissions from combustion. However, the direct analysis does not show full picture of the problem as significant emissions of GHG appear also in the process of mining and transportation of fuel. It is demonstrated in the paper that comparison of power technologies from the GHG point of view has to be done using the cumulative calculus covering the whole cycle of fuel mining, processing, transportation and end-use. From this point of view coal technologies are in comparable level as gas technologies while nuclear power units are characterised with lowest GHG emissions. Mentioned technologies are compared from the point of view of GHG emissions in full cycle. Specific GHG cumulative emission factors per unit of generated electricity are determined. These factors have been applied to simulation of the influence of introduction of nuclear power units on decrease of GHG emissions in domestic scale. Within the presented simulations the prognosis of domestic power sector development according to the Polish energy policy till 2030 has been taken into account. The profitability of introduction of nuclear power units from the point of view of decreasing GHG emissions has been proved.
The understanding the influence of biological processes on the characteristics of the signals backscattered by the sea floor is crucial in the development of the hydroacoustical benthic habitat classification techniques. The impact of the microphytobenthos photosynthesis on the acoustical backscattering properties of the Atlantic sandy sediments was previously demonstrated by Holliday et al. (2004) and Wildman and Huettel (2012). To account for the sensitivity of the hydroacoustical classification techniques to the backscattering properties of local marine sediments, it is important to understand the microphytobenthos photosynthesis impact for the Baltic Sea where the techniques are being actively developed now. This is the main motivation of the paper. In the paper the influence of the microphytobenthos photosynthesis on the characteristics of the echo signals reflected by sandy sediments in the typical Baltic temperature and the salinity conditions is discussed. The interdisciplinary multiday laboratory experiment was conducted to study the impact of benthic microalgal photosynthesis on the characteristics of the echo signal reflected by sandy sediments. Hydroacoustical data were collected under controlled constant light, temperature and salinity conditions. The oxygen content at different levels of the water column was simultaneously monitored.