Major works by Leon Koj deal with the issues of semiotics, logics, philosophy of language, philosophy of mind and ethics. Many of them refer to aspects of communication, however, this is not the main subject of his considerations. These references relate to the problems of satisfying: 1. the logical criteria, 2. the methodological criteria, 3. the ethical criteria, 4. the semiotic criteria. This article is dedicated to defining the semiotic criteria. It briefly covers basic semiotic notions present in Koj’s works. On the basis of Koj’s assumptions the concept of semiotics conditions for the realisation and functions of the communication process is defined.

Celem rozważań jest ukazanie ciągłości w badaniach semiotycznych Profesora Jerzego Pelca dotyczących natury znaku i przedmiotu badań semiotyki. Artykuł dotyczy związków koncepcyjnych między pojęciami: użycia wyrażeń, sposobu użycia, znaku, wnioskowania semiotycznego, semiotyki. Argumentuje się, że mimo zmian w określaniu niektórych pojęć semiotycznych, to z perspektywy całej drogi badawczej istnieje głębsza konsekwencja w rozumieniu zarówno samego pojęcia znaku, jak i dziedziny badań semiotycznych. Takim pomostem łączącym wczesne pojęcie użycia wyrażeń z semiotyką pojmowaną później jako nauka o poznaniu i komunikacji jest dla J. Pelca między tymi okresami badawczymi pojęcie znaku oparte na czynności poznawczej, jaką jest wnioskowanie semiotyczne.

The shell and coil heat exchangers are commonly used in heating, ventilation, nuclear industry, process plant, heat recovery and air conditioning systems. This type of recuperators benefits from simple construction, the low value of pressure drops and high heat transfer. In helical coil, centrifugal force is acting on the moving fluid due to the curvature of the tube results in the development. It has been long recognized that the heat transfer in the helical tube is much better than in the straight ones because of the occurrence of secondary flow in planes normal to the main flow nside the helical structure. Helical tubes show good performance in heat transfer enhancement, while the uniform curvature of spiral structure is inconvenient in pipe installation in heat exchangers. Authors have presented their own construction of shell and tube heat exchanger with intensified heat transfer. The purpose of this article is to assess the influence of the surface modification over the performance coefficient and effectiveness. The experiments have been performed for the steady-state heat transfer. Experimental data points were gathered for both laminar and turbulent flow, both for co current- and countercurrent flow arrangement. To find optimal heat transfer intensification on the shell-side authors applied the number of transfer units analysis.

The Bulletin of the Polish Academy of Sciences: Technical Sciences (Bull.Pol. Ac.: Tech.) is published bimonthly by the Division IV Engineering Sciences of the Polish Academy of Sciences, since the beginning of the existence of the PAS in 1952. The journal is peer‐reviewed and is published both in printed and electronic form. It is established for the publication of original high quality papers from multidisciplinary Engineering sciences with the following topics preferred: Artificial and Computational Intelligence, Biomedical Engineering and Biotechnology, Civil Engineering, Control, Informatics and Robotics, Electronics, Telecommunication and Optoelectronics, Mechanical and Aeronautical Engineering, Thermodynamics, Material Science and Nanotechnology, Power Systems and Power Electronics.

Journal Metrics: JCR Impact Factor 2018: 1.361, 5 Year Impact Factor: 1.323, SCImago Journal Rank (SJR) 2017: 0.319, Source Normalized Impact per Paper (SNIP) 2017: 1.005, CiteScore 2017: 1.27, The Polish Ministry of Science and Higher Education 2017: 25 points.

Abbreviations/Acronym: Journal citation: Bull. Pol. Ac.: Tech., ISO: Bull. Pol. Acad. Sci.-Tech. Sci., JCR Abbrev: B POL ACAD SCI-TECH Acronym in the Editorial System: BPASTS.

In this study, the influences of different parameters at performance two-phase closed thermosiphon (TPCT) was presented. It has been confirmed that the working fluid, as well as operating parameters and fill ratio, are very important factors in the performance of TPCT. The article shows characteristics of gravitational tube geometries, as well as the technical characteristic of the most important system components, i.e., the evaporator/condenser. The experiment’s plan and the results of it for the two-phase thermosiphon for both evaluated geometries with varying thermal and fluid flow parameters are presented. Experiments were performed for the most perspective working fluids, namely: water, R134a, SES36, ethanol and HFE7100. Obtained research proves the possibility to use TPCT for heat recovery from the industrial waste water.

The Bulletin of the Polish Academy of Sciences: Technical Sciences (Bull.Pol. Ac.: Tech.) is published bimonthly by the Division IV Engineering Sciences of the Polish Academy of Sciences, since the beginning of the existence of the PAS in 1952. The journal is peer‐reviewed and is published both in printed and electronic form. It is established for the publication of original high quality papers from multidisciplinary Engineering sciences with the following topics preferred: Artificial and Computational Intelligence, Biomedical Engineering and Biotechnology, Civil Engineering, Control, Informatics and Robotics, Electronics, Telecommunication and Optoelectronics, Mechanical and Aeronautical Engineering, Thermodynamics, Material Science and Nanotechnology, Power Systems and Power Electronics.

Journal Metrics: JCR Impact Factor 2018: 1.361, 5 Year Impact Factor: 1.323, SCImago Journal Rank (SJR) 2017: 0.319, Source Normalized Impact per Paper (SNIP) 2017: 1.005, CiteScore 2017: 1.27, The Polish Ministry of Science and Higher Education 2017: 25 points.

Abbreviations/Acronym: Journal citation: Bull. Pol. Ac.: Tech., ISO: Bull. Pol. Acad. Sci.-Tech. Sci., JCR Abbrev: B POL ACAD SCI-TECH Acronym in the Editorial System: BPASTS.

Stanisław Lorenc graduated from the Wrocław University, where he obtained his master degree in geology. In 1973, he was awarded a doctoral degree, in 1980 he obtains habilitation (postdoctoral degree) and in 1994 he was promoted to full professor. In 1988 Stanisław Lorenc moves to Adam Mickiewicz University in Poznań and became a director of the Institute of Geology. He gained a global reputation as an explorer of the ocean floor. In the years 1996–2002 professor Lorenc was the vice-rector in the team of the then rector, prof. Stefan Jurga. In the years 2002–2008 he was the rector of the University of Adam Mickiewicz University in Poznan. Rector's term of Stanisław Lorenc covered a wide spectrum of scientific research, education, development of the scientific staff, international cooperation and cultural, sporting and social activities, student affairs and infrastructure. The most important at the university for prof. Stanisław Lorenc were people of academic and administrative staff, students and all those who collaborated with the university. Saying farewell during academic senate the rector, prof. Andrzej Lesicki, said: You were not only a great rector, an outstanding scholar, but also, and perhaps above all, a good, warm man. Professor Stanisław Lorenc died on January 19, 2020. He was 77 years old.

Two-dimensional numerical investigations of the fluid flow and heat transfer have been carried out for the laminar flow of the louvered fin-plate heat exchanger, designed to work as an air-source heat pump evaporator. The transferred heat and the pressure drop predicted by simulation have been compared with the corresponding experimental data taken from the literature. Two dimensional analyses of the louvered fins with varying geometry have been conducted. Simulations have been performed for different geometries with varying louver pitch, louver angle and different louver blade number. Constant inlet air temperature and varying velocity ranging from 2 to 8 m/s was assumed in the numerical experiments. The air-side performance is evaluated by calculating the temperature and the pressure drop ratio. Efficiency curves are obtained that can be used to select optimum louver geometry for the selected inlet parameters. A total of 363 different cases of various fin geometry for 7 different air velocities were investigated. The maximum heat transfer improvement interpreted in terms of the maximum efficiency has been obtained for the louver angle of 16° and the louver pitch of 1.35 mm. The presented results indicate that varying louver geometry might be a convenient way of enhancing performance of heat exchangers.

The paper presents investigation into the single water microjet surface cooling producing evaporating film. Reported tests were conducted under steady state conditions. Experiments were conducted using the nozzle size of 70 and 100 μm respectively. In the course of investigations obtained were experimental relations between heat flux and wall superheating. It was proved that the phenomenon is similar to that of pool boiling but the boiling curves are showing a smaller value of critical heat flux (CHF) that the stagnant pool boiling. Values of CHF are also reduced with decreasing liquid subcooling. Theoretical model of surface cooling by evaporating microjet impingement in the stagnation point was described theoreticaly. Results of experiments were compared with predictions by the model showing a good consistency.

The article presents detailed two-phase adiabatic pressure drops data for refrigerant R134a. Study cases have been set for a mass flux varying from 200 to 400 kg/m2s, at the saturation temperature of 19.4°C. Obtained experimental data was compared with the available correlations from the literature for the frictional pressure drop during adiabatic flow. Influence of mixture preparation on pressure drop was investigated, for varying inlet subcooling temperature in the heated section. The flow patterns have also been obtained by means of a high-speed camera placed in the visualization section and compared with literature observations.