As the cost of fuel rises, designing efficient solar air heaters (SAH) becomes increasingly important. By artificially roughening the absorber plate, solar air heaters’ performance can be augmented. Turbulators in different forms like ribs, delta winglets, vortex generators, etc. have been introduced to create local wall turbulence or for vortex generation. In the present work, a numerical investigation on a solar air heater has been conducted to examine the effect of three distinct turbulators (namely D-shaped, reverse D- and U-shaped) on the SAH thermo-hydraulic performance. The simulation has been carried out using the computational fluid dynamics, an advanced and modern simulation technique for Reynolds numbers ranging from 4000 to 18000 (turbulent airflow). For the purpose of comparison, constant ratios of turbulator height/hydraulic diameter and pitch/turbulator height, of 0.021 and 14.28, respectively, were adopted for all SAH configurations. Furthermore, the fluid flow has also been analyzed using turbulence kinetic energy and velocity contours. It was observed that the U-shaped turbulator has the highest value of Nusselt number followed by D-shaped and reverse D-shaped turbulators. However, in terms of friction factor, the D-shaped configuration has the highest value followed by reverse D-shaped and U-shaped geometries. It can be concluded that among all SAH configurations considered, the U-shaped has outperformed in terms of thermohydraulic performance factor.

The trend of reducing electricity consumption and environmental protection has contributed to the development of refrigeration technologies based on the thermal effect of adsorption. This article proposes a methodology for conducting numerical simulations of the adsorption and desorption processes. Experimental data available in the literature were used as guidelines for building and verifying the model, and the calculations were carried out using commercial computational fluid dynamics software. The simulation results determined the amount of water vapor absorbed by the adsorbent bed and the heat generated during the adsorption process. Throughout the adsorption process, the inlet water vapor velocity, temperature, and pressure in the adsorbent bed were monitored and recorded. The results obtained were consistent with the theory in the literature and will serve as the basis for further, independent experimental studies. The validated model allowed for the analysis of the effect of cooling water temperature on the sorption capacity of the material and the effect of heating water temperature on bed regeneration. The proposed approach can be useful in analyzing adsorption processes in refrigeration applications and designing heat and mass exchangers used in adsorption systems.

Thermochemical treatment processes are used to produce a surface layer of the workpiece with improved mechanical properties. One of the important parameters during the gas nitriding processes is the temperature of the surface. In thermochemical treatment processes, there is a problem in precisely determining the surface temperature of heat-treated massive components with complex geometries. This paper presents a simulation of the heating process of a die used to extrude aluminium profiles. The maximum temperature differences calculated in the die volume, on the surface and at the most mechanically stressed edge during the extrusion of the aluminum profiles were analysed. The heating of the die was simulated using commercial transient thermal analysis software. The numerical calculations of the die assumed a boundary condition in the form of the heat transfer coefficient obtained from experimental studies in a thermochemical treatment furnace and the solution of the nonstationary and non-linear inverse problem for the heat conduction equation in the cylinder. The die heating analysis was performed for various heating rates and fan settings. Major differences in the surface temperature and in the volume of the heated die were obtained. Possible ways to improve the productivity and control of thermochemical treatment processes were identified. The paper investigates the heating of a die, which is a massive component with complex geometry. This paper indicates a new way to develop methods for the control of thermochemical processing of massive components with complex geometries.

The primary objective is to perform a numerical synthesis of a Williamson fluid that has nanoparticles added to it and is directed toward a vertical cone in a uniform transverse magnetic field, under heat and mass transport, suction and injection, and convective boundary conditions. For this particular fluid flow, by utilising similarity transformations, the partial differential equations are transformed into ordinary differential equations. Calculating these kinds of equations with their suitable bounds requires the Runge–Kutta technique in combining a shooting strategy. The functions of a vast number of parameters are graphically represented and assessed on flow field profiles. The results show the local skin friction, local Nusselt number, and local Sherwood number and the changing values of the flow constraints. Finally, the results are compared to those from the previously published works and found to be in good agreement.

This paper presents new results for the dynamic behaviour of fluid around a rotating turbulator in a channel. The turbulator has a propeller form which is placed inside a flat channel. The research was carried out using 3D numerical simulation. The rationale of the experiment was as follows: we put a propeller-turbulator inside a flat channel, and then we insert a water flow inside the channel. The turbulator rotates at a constant and uniform speed. The main points studied here are the effect of the presence of turbulator and its rotational direction on the flow behaviour behind the turbulator. The results showed that the behaviour of flow behind the turbulator is mainly related to the direction of turbulator rotating. Also, the studied parameters affect coefficients of drag force and power number. For example, when the turbulator rotates in the positive direction, the drag coefficient decreases in terms of rotational speed of the turbulator, while the drag coefficient increases in terms of rotational speed when the turbulator rotates in the negative direction.

This work is an attempt to study the behaviour of fluid in the mixing vessel with a two-bladed or four-bladed impeller. The working fluid is complex, of a shear-thinning type and the Oswald model is used to describe the fluid viscosity. The study was accomplishedby numerically solving the governing equations of momentum and continuity. These equations were solved for the following range of conditions: 50–1000 for the Reynolds number, 0–0.15 for the baffle length ratio, and the number of impeller blades 2 and 4. The simulations were done for the steady state and laminar regime. The results show that the increase in baffle length (by increasing the ratio baffle length ratio) decreases the fluid velocity in the vessel. Increasing the speed of rotation of the impeller and/or increasing the number of blades improves the mixing process. Also, the length of the baffles does not affect the consumed power.

Solar photovoltaic power is widely utilized in the energy industry. The performance of solar panels is influenced by different variables, including solar radiation, temperature, wind speed, relative humidity and the presence of haze or dirt. Outdoor solar panels are particularly susceptible to a decrease in energy efficiency due to the accumulation of dust particles in the air, which occurs as a result of natural weather conditions. The extent of dust deposition is primarily determined by factors such as the tilt angle of the panel, wind direction, cleaning frequency as well as local meteorological and geographical conditions. The dust on the solar cell glazing reduces the optical transmittance of the light beam, causing shadowing and diminishing the energy conversion productivity of the panels. Sand storms, pollution levels and snow accumulations all significantly impact the photovoltaic panel performance. These circumstances reduce the efficiency of solar panels. The experiment was carried out on two identical dust-accumulated and dust-free panels. The evaluation was carried out in two different situations on the offgrid stand-alone system: in a simulated atmosphere and in an open space during the day. The current-voltage curves have been developed for both panels at various tilt degrees. The features provide sufficient information to analyse the performance of the panels under consideration. The measurements demonstrate that as dust collects on the panel’s surface, the average output power and short circuit current decrease dramatically. The installation tilt angle affected the ratio of efficiency and average power outputs of dusty and clean panels.

Laminar mixed convection heat transfer in a vented square cavity separated by a porous layer filled with different nanofluids (Fe3O4, Cu, Ag and Al2O3) has been investigated numerically. The governing equations of mixed convection flow for a Newtonian nanofluid are assumed to be two-dimensional, steady and laminar. These equations are solved numerically by using the finite volume technique. The effects of significant parameters such as the Reynolds number (10 ≤ Re ≤ 1000), Grashof number (103 ≤ Gr ≤ 106), nanoparticle volume fraction (0.1 ≤ ϕ ≤ 0.6), porous layer thickness (0 ≤ γ ≤ 1) and porous layer position (0.1 ≤ δ ≤ 0.9) are studied. Numerical simulation details are visualized in terms of streamline, isotherm contours, and average Nusselt number along the heated source. It has been shown that variations in Reynolds and Darcy numbers have an impact on the flow pattern and heat transfer within a cavity. For higher Reynolds (Re >100), Grashof (Gr > 105) numbers and nanoparticles volume fractions the heat transfer rate is enhanced and it is optimal at lower values of Darcy number (Da = 10-5). In addition, it is noticed that the porous layer thickness and location have a significant effect on the control of the heat transfer rate inside the cavity. Furthermore, it is worth noticing that Ag nanoparticles presented the largest heated transfer rate compared to other nanoparticles.

Thermophysical properties of frozen soil have a great influence on the quality of cast-in-place concrete piles. In this paper, the embedded concrete temperature monitoring system is used to test the variation law of the concrete temperature during the construction of the bored pile. Thermophysical properties of permafrost around piles are tested. Based on the theory of three-phase unsteady heat conduction of soil, the influence of specific heat capacity, thermal conductivity, thermal diffusivity, and latent heat of phase transformation on the temperature change of a concrete pile is systematically studied. The thermal parameter is obtained which exerts the most significant influence on the temperature field. According to the influence degree of frozen soil on pile temperature, the order from high to low is thermal conductivity, thermal diffusivity, latent heat of phase change, and specific heat capacity. The changes in pile wall temperature caused by the change of these properties range between 2.60–10.97°C, 1.49– 9.39°C, 2.16–2.36°C, and 0.24–3.45°C, respectively. The change percentages of parameters vary between 35.77–47.12%, 12.22–40.20%, 12.46–32.25%, and 3.83–20.31%, respectively. Therefore, when designing and constructing concrete foundation piles, the influence of the thermal conductivity of frozen soil on concrete pile temperature should be considered first. The differences between the simulated and measured temperature along the concrete pile in the frozen soil varying with the respective thermal properties are: –2.99– 7.98°C, –1.89–4.99°C, –1.20–1.99°C, and –1.76–1.27°C. Polyurethane foam and other materials with small thermal conductivity can be added around the pile to achieve pile insulation.

Chromosome numbers of 17 taxa of Hieracium s.str. from Bulgaria, Greece, Poland and Romania are specified and their metaphase plates are illustrated. Chromosome numbers are published for the first time for H. engleri R. Uechtr. (4x), H. kritschimanum Mattfeld & Zahn (3x), H. latifolium Link (3x), H. tephrosoma subsp. amaurocranum Zahn (5x), as well as five undescribed species belonging to the H. lachenalii agg. (3x), H. rohacsense agg. (4x), H. vagneri agg. (4x), H. vranjanum agg. (4x) and H. wiesbaurianum agg. (3x), and a new hybrid between H. caesium s.lat and H. umbellatum (4x).

Cell wall components, especially arabinogalactan proteins (AGPs) and pectins as the source of signaling molecules active in cell-to-cell communication, are involved in many biological processes, including plant growth and development. Understanding the mechanisms of intercellular communication is particularly important in the context of reprogramming cell fate and transition from somatic to germline identity. The present study focuses on immunodetection of some pectic epitopes and AGPs in young ovules of selected Hieracium, Pilosella and Taraxacum species. The purpose of this research was to answer the questions: (1) whether the distribution of pectins and AGPs is related to the mode of reproduction and (2) whether their spatial and temporal distribution in young ovules may herald a later differentiation of the nutrient tissue present in the integument of mature ovules. We analyzed the localization of low and highly methyl-esterified pectins and AGP epitopes using monoclonal antibodies, i.e., LM19, LM20, JIM13, respectively. Our research found no significant differences in the localization of pectins and AGPs in young ovules of sexual and apomictic species, and the initial distribution pattern of these compounds did not appear to be related to the subsequent differentiation of the periendothelial nutrient zone. The presented findings may confirm the existence of a general developmental trend in the spatial and temporal distribution of pectins and AGPs during the maturation of ovules in angiosperms.

Child-authored poetry is one of the most remarkable and fascinating phenomena in the contemporary Chinese poetry world. However, for all its immense popularity among Chinese readers and attractivity for professional, adult poets, due to its unclear ontological status and lack of well-proven methodological tools that would be easily applicable to it, it has thus far remained beyond the scope of literary-critical and scholarly interests. The present paper offers a broad panoramic view of Chinese children’s poetry through six case studies of individual young authors and collective initiatives aimed at the artistic activization of certain groups of children, discussing the educational and social significance of children’s poetry writing, its complicated reception patterns, as well as its entanglement with various literary-political discourses. Subsequently, the study delves into the aesthetic, conceptual, and philosophical aspects of children’s works. The final part analyses the essential theoretical-philosophical questions that child-authored verse asks with regard to poetry at large, prompting us to rethink notions such as authorship or “poeticness” and the definition of poetry per se. The author proposes the metaphor of asymptotic freedom to illustrate how marginal phenomena of questionable status contribute to maintaining the distinctness and coherence of the field of poetry as a whole.

After Italy declared war on Great Britain and France on June 10, 1940 Turkey remained neutral, despite the fact that the treaty with Western powers obliged it to enter the war in such circumstances. Turkish government referred to the Second Protocol attached to the Treaty of Mutual Assistance which made possible for the Turkish side to ignore their obligations in case a threat of armed conflict with Soviet Union. However it is still not known if this was real reason for Turkish decision. The aim of this article is to review interpretations of Turkish attitude that have been present in historiography since the war. It includes short-term and long-term factors of Turkish decision from June 1940. In addition, attention was concentrated on British intelligence sources, which, in relation to the period between spring and summer of 1940, have not yet been taken into account by scholars when trying to determinate Turkish motives.

In the article the author deals with the years the famous Turkologist and historian Ahmet Zeki Velidi Togan (1890–1970), who is known for his great edition of the 10th-century Arabic travel account of Ibn Faḍlān was working and teaching at Rheinische Friedrich- Wilhelms-Universität in Bonn (1935–1938). Various documents relating to events from this period are reproduced in the article (including his appointment to the Oriental Seminar at the university, his appointment as a member of the Finno-Ugric Society in Helsinki, his appointment as an honorary professor, a research stay in Turkey, his leave of absence to carry out a lectureship at the Georg August University in Göttingen, and finally his defence in response to accusations regarding his “political reliability”, which are not known in detail. This defence was made both by Paul Kahle and by himself in the form of an account of his political activities in the years 1917–1929, the full text of which is appended and which was later also used by Togan himself in his autobiography.

The purpose of the paper is to present difficulties lying ahead of translators of literary works in which specialized terminology is used. The authors have chosen as their research material one of the most well-known Polish alexandrines titled Pan Tadeusz czyli ostatni zajazd na Litwie. Historia szlachecka z r. 1811 i 1812, we dwunastu księgach, wierszem [“Master Thaddeus, or the Last Foray in Lithuania: A Tale of the Gentry in the Years 1811–1812, in Twelve Books of Verse”] and its translations into English and Korean. As the main purpose was to analyze the translation of hunting terminology into Korean, the authors have chosen an English translation rendered approximately at the same time as the Korean one. Therefore, the English language version has been used instrumentally. The research material has been limited to one plot only, that is to say the trials and tribulations of one of the heroines, whose name is Telimena and her chase for a husband. The main research method is the comparison of parallel texts. Apart from that, the authors have also resorted to techniques of providing equivalents and classifications of translation errors and mistakes. The findings prove that proper rendering of culture-bound terminology is very difficult and consultations with specialists are frequently necessary to achieve high quality translation products.

The aim of this article is an attempt to analyse the world-famous documentary film entitled The Parade (Polish title Defilada). The film has a unique narrative structure, as it belongs to the performing arts, and makes use of hyperbole which represents one of rhetorical tropes. Thus, the narration of the film is characterised by a specific rhetorical order which follows the rules of composing a text about art, culture and other phenomena. The result is often art itself. At the level of creative intention, Andrzej Fidyks’s films constitute spectacles which have to be appealing enough to attract the attention of a contemporary viewer. Thus, spectacularity of this film is not only a feature directly related to audiovisual art. It constitutes an aesthetic value as well, and the spectacle appears as a parade in honour of the country’s leader. Research methods include two types of text analysis, i.e. the rhetorical analysis, and the analysis based on film studies. The neo-rhetorical (i.e., argumentative) approach to the cinematographic text is visible in studying The Parade as a documentary which was created under conditions of full control over the director, together with lack of access to information. Perversity is a deliberate argumentative strategy, as Fidyk uses it in order to explain to the viewers the reality of the visited country.

The city of Homs, formerly known as Emesa, strategically located in the central region of Syria, has been long linked to a folk belief that portrays its inhabitants as mad and fool. Historical and traditional sources also link the alleged madness and foolishness of the Homsians to the day of Wednesday, the so-called “Day of the Fool” or “Homsians’ Feast”, which is considered a special day. The legend regarding the “Day of the Fool” and its celebration during Wednesdays has been passed down orally in the local culture and its origins likely trace back to ancient times when the city was still called Emesa. Therefore, this article attempts at reconstructing history and origins about this folk belief, and exploring the reasons behind the supposed madness and foolishness of the inhabitants of Homs and their connections to Wednesdays by comparing three studies published after 2000s in Arabic by Homsian intellectuals, namely Al-Aḥmad, Samʽān, and Kadr.

Developments in Arctic international relations resulting from Russia's aggression against Ukraine in 2022 stand as the most serious crisis in regional cooperation since the end of the Cold War. This crisis has necessitated a re-evaluation of the regional governance system and an update of the political strategies of Arctic stakeholders. In this article, based on qualitative research methodology, we explore the challenges to regional cooperation in the near and mid-term perspectives, and we discuss how the current situation can contribute to a transformation of Poland's role in the Arctic, particularly in the field of science diplomacy. The study includes a critical analysis of the content of the Polish Polar Policy officially adopted in 2020, as well as its implementation. We conclude that the future of Arctic relations will be based not only on the hindered functioning of the Arctic Council but also on the emergence of new competitive forms of collaboration to be developed by Russia and its partners, distancing themselves from Western states. In such a situation and in the face of the emerging opposition between the two blocs, the role of science diplomacy will substantially increase and gain new dynamics. This, in turn, means that although Poland's Arctic policy in its present framework requires only minor conceptual correction, its implementation should be considerably built up and advanced.