The aim of the paper is a steady-state inverse heat transfer problem for plate-fin and tube heat exchangers. The objective of the process control is to adjust the number of fan revolutions per minute so that the water temperature at the heat exchanger outlet is equal to a preset value. Two control techniques were developed. The first is based on the presented mathematical model of the heat exchanger while the second is a digital proportional-integral-derivative (PID) control. The first procedure is very stable. The digital PID controller becomes unstable if the water volumetric flow rate changes significantly. The developed techniques were implemented in digital control system of the water exit temperature in a plate fin and tube heat exchanger. The measured exit temperature of the water was very close to the set value of the temperature if the first method was used. The experiments showed that the PID controller works also well but becomes frequently unstable.

The paper summarizes the debate concerning the divine hiddenness argument. First, it presents two versions of the argument that was initially formulated by J.L. Schellenberg and subsequently discussed over the last twenty years and it marks its most important theses. Then the author indicates some possible rebuttals, segregating them according to the challenged premises. Particularly noteworthy, he argues, are these theistic answers that accuse the images of God assumed by the hiddenness argument of excessive anthropomorphism and those that try to point out higher goods justifying divine hiddenness. In conclusion the author claims that the hiddenness argument proves atheism only if by theism one understands theistic personalism. Other positions, such as ultimism or theism of transcendence, are not threatened by the argument.

This article deals with the reception of Arthur Rimbaud’s poetry and his biographic legend by the poets of the last decades of 19th and the first decades of the 20th century, though, in fact, its earliest phase belongs to the literary period of pre-Modernist, anti-Romantic reaction (which described itself by the name Positivism, epitomized by the novels of Bolesław Prus). The process of Rimbaud’s reception proceeded in two dimensions, on the intergenerational level and in dialogue between poets and translators. Interestingly, it acted as a veritable catalyst of changes in the poetics of writers across the spectrum, from the old school (Józef Weyssenhof and Eliza Orzeszkowa) to the modernist avant-garde. The influence of Rimbaud was by no means uniform and went beyond the usual names like Zenon Przesmycki (Miriam), Julian Tuwim or Jarosław Iwaszkiewicz. This article casts its net widely to include representatives of three generations, among them some of the less acclaimed authors.

Renewable energy development is crucial for resolving global warming issues and achieving

sustainable development goals. The objective of this paper is to reveal renewable energy trends

using statistical data to identify the most developed technologies in the field, their distribution by

territory, checking the interrelation between investments in R&D and patent activity.

The changes in total investments made in renewables are studied for 2004–2019 and the increasing

trend has been observed with some fluctuations in certain years, major current investments in solar

and wind energy are detected. The dynamics of international patenting activity in solar and wind

technologies, geothermal and fuel cells, the total number of PCT applications over the past 10 years

by geographic region are considered. The results show some differences across various renewable

technologies. Solar is the most patented, wind and fuel cells are less patented but solar and wind

have shown an uptrend for the last five years, while fuel cell technologies showed a decline after

2008. Geothermal is the least patented.

The comparison between investment and patent application trends in renewables undercovers some

important issues – the leading role of Japan in patenting under the PCT procedure, while China is

a major investor in renewable energy; the US and Europe with big investments in renewables are

also leading in patent registration.

Correlation between investment in R&D and patenting activity in the field of global renewable

energy should be emphasized (correlation coefficient R = 0,849 for 2002–2019). Since private

and public investment is strongly stimulated by domestic renewable energy policies, IP indicators

can help identify policy instruments and their effectiveness within the further research

framework.

Qualitative migration researchers today often use one or more of three concepts – mobility, transnationalism and integration – to make sense of the complexities of contemporary migrants’ lives. Collectively, researchers identify these as the three fundamental characteristics of migranthood. Being a migrant is about, for example, planning return visits, maintaining (or not maintaining) relations with people in the sending country or being preoccupied with learning to speak the receiving-society majority language. Qualitative interviewing suggests that each migrant is uniquely situated along various mobility, transnational and integration continuums. Migrants have many social identities as well as migranthood and the existence of these other, intersecting, social identities (such as social class, lifestage and gender) helps to determine their location on the continuums: for example, how often they are mobile and how much they can be mobile. The article draws on interviews in Poland with Ukrainians and Polish return migrants to show how (former) migrants conceptualise shared Ukrainian-Polish migranthood along these three continuums.

An investigation of cyanobacterial microflora in the northern, deglaciated part of James Ross Island in the NW part of the Weddell Sea, Antarctica , was conducted during the Antarctic summer season 2005-2006. Five main types of habitats with dominant cyanobacterial assemblages were analyzed (soils, seepages, streams, wetted rocky walls and lakes), and main ecological variables were measured (pH, temperature, intensity of global radiation, conductivity and nutrients), as a background for further ecological and ecophysiological studies. The definable traditional cyanobacterial morphospecies were identified.

The results of the application and evaluation of the r.sun model for calculation of the total solar radiation for the Wedel Jarlsberg Land (SW Spitsbergen) are presented. Linke Turbidity Factor (LTF), which is the obligatory parameter for direct and diffused radiation calculations with the r.sun model, is derived here with the empirical formula and meteoro− logical measurements. Few different approaches for calculation of LTF are presented and tested. The r.sun model results, calculated with these various LTF, are evaluated through comparison with total solar radiation measurements gathered at Polish Polar Station. The r.sun model is found to be in good agreement with the measurements for clear sky condi− tions, with the explained variance (R2) close to 0.9. Overall, the model slightly underesti− mates the measured total radiation. Reasonable results were calculated for the cloudiness condition up to 2 octas, and for these r.sun model can be considered as a reliable and flexible tool providing spatial data on solar radiation for the study area.