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  • The Influence of Antitumor Unsymmetrical Bisacridines on 3D Cancer Spheroids Growth and Viability
    • Jolanta Kulesza
    • Monika Pawłowska
    • Ewa Augustin
    2021 Pełny tekst MOLECULES

    The culture of 3D spheroids is a promising tool in drug development and testing. Recently, we synthesized a new group of compounds, unsymmetrical bisacridines (UAs), which exhibit high cytotoxicity against various human cell lines and antitumor potency against several xenografts. Here, we describe the ability of four UAs—C-2028, C-2041, C-2045, and C-2053—to influence the growth of HCT116 and H460 spheres and the viability of HCT116 cells in 3D culture compared with that in 2D standard monolayer culture. Spheroids were generated using ultra-low-attachment plates. The morphology and diameters of the obtained spheroids and those treated with UAs were observed and measured under the microscope. The viability of cells exposed to UAs at different concentrations and for different incubation times in 2D and 3D cultures was assessed using 7-AAD staining. All UAs managed to significantly inhibit the growth of HCT116 and H460 spheroids. C-2045 and C-2053 caused the death of the largest population of HCT116 spheroid cells. Although C-2041 seemed to be the most effective in the 2D monolayer experiments, in 3D conditions, it turned out to be the weakest compound. The 3D spheroid culture seems to be a suitable method to examine the efficiency of new antitumor compounds, such as unsymmetrical bisacridines.

  • The influence of atmospheric circulation on the occurrence of dry and wet periods in Central Poland in 1954–2018
    • Andrzej Araźny
    • Arkadiusz Bartczak
    • Rafał Maszewski
    • Michał Krzemiński
    2021 Pełny tekst THEORETICAL AND APPLIED CLIMATOLOGY

    This work presents the influence of atmospheric circulation on the occurrence of dry and wet periods in the central Polish region of Kujawy. The material on which the authors relied encompassed monthly totals of precipitation obtained from 10 weather stations in the period 1954–2018. Both dry and wet periods have been identified on the basis of monthly values of the Standardised Precipitation Index (SPI). Additionally, the calendar of circulation types over Central Poland was used to determine the atmospheric circulation indices: western (W), southern (S) and cyclonicity (C). The analyses have indicated that the region concerned experiences low precipitation totals in comparison with the rest of Poland. According to the circulation indices W, S and C, for Central Poland, the air mass advection from the West prevails over that from the East. Moreover, a slightly more frequent inflow of air from the South than from the North has been observed. The frequency of anticyclonic situations is higher than that of the cyclonic types in this part of Europe. Drought spells occurred in the study area at a clear dominance of anticyclonic circulation, with the inflow of air mostly from the North and with increased westerly circulation. On the other hand, the occurrence of wet periods was mainly influenced by cyclonic circulation during the advection of the masses from the South and West. Dry and wet periods accounted for 28% and 27% of the study period, respectively.

  • The Influence of Cement Type on Early Properties of Cold In-Place Recycled Mixtures
    • Bohdan Dołżycki
    • Mariusz Jaczewski
    • Cezary Szydłowski
    2021 Pełny tekst

    Cold in-place recycling is a commonly used maintenance treatment in rehabilitation of low and medium volume roads in Poland. Typically, two types of binding agents are used—cement and bituminous emulsion (or foamed bitumen).Due to the harsh Polish climate with many freeze/thaw cycles and frequent occurrence of saturated conditions, the used amounts of cement are higher than those commonly used in warmer parts of Europe. While there is usually only one type of bituminous emulsion dedicated for cold recycling on the market, there are numerous types of cements, which differ in chemical composition and properties. The conducted research presents possible development of cold recycled mixture properties over curing time, taking into account the type of cement used. Two types of cement were tested in laboratory investigation—common Portland CEM I 32.5 R cement and Portland-fly ash CEM II 32.5 B-V cement with longer setting time. Cold recycled mixtures were designed with the same composition and amount of binding agents, but differed in the type of cement used. For both mixtures, indirect tensile strength and modulus were tested after 7, 28 and 90 days of curing in laboratory conditions. The laboratory tests confirmed lower values of strength and modulus for the fly ash cement after 7 and 28 days in comparison to the typical cement, but after 90 days the properties of both tested mixtures presented similar values. If the overall predicted fatigue life and long-term mechanical properties are the same, the use of slow-setting cementsmay result in reduction of reflective cracking on the surface of the pavement. In the case of low and medium volume roads, where there is no need for fast paving of the asphalt layers and more time may be allowed for the cold-recycled mixture to achieve the required initial strength, slow-setting cements should be considered as a viable treatment for reduction of the risk of reflective cracking.

  • The influence of climate change on the life insurance in the EU: A panel data approach
    • Oleksandr Melnychenko
    • Tetyana Kalna-Dubinyuk
    • Olha Vovchak
    • Tetiana Girchenko
    2021 Pełny tekst E3S Web of Conferences

    The financial sector, as one of the most sensitive economic sectors, is alert to all trends and changes in the environment. The aim of the article is to study the impact of climate change on the life insurance market using panel data from 28 countries of the European Union (EU) for the last 9 years. This study is based on a panel model, where the amount of premiums under life insurance contracts is defined as a function of the fundamental factor of climate change - greenhouse gas emissions. According to empirical findings, an increase in greenhouse gas emissions per thousand tons leads to an increase in the amount of life insurance premiums by 0.1786 million euros. It has also been found that an increase in greenhouse gas emissions per thousand tons leads to an increase in deaths in the European Union by 1.0442 people, and these consequences are statistically significant. In general, our results suggest that the life insurance market as well as the nonlife insurance market is dependent on climate change. The empirical results of this study provide valuable insight into how greenhouse gas emissions affect mortality in the European Union.

  • The Influence of Co-Fermentation of Agri-Food Waste with Primary Sludge on Biogas Production and Composition of the Liquid Fraction of Digestate
    • Anna Wilińska-Lisowska
    • Monika Ossowska
    • Krzysztof Czerwionka
    2021 Pełny tekst ENERGIES

    Energy self-sufficiency is a current trend in wastewater treatment plants. This effect can be achieved by increasing the production of electricity from biogas and by reducing energy consumption for technological processes. One idea, in line with the circular economy concept, is the use of waste rich in organic matter as co-substrates for the fermentation process. The aim of this study was to determine the effect of waste co-fermentation on biogas production and nitrogen concentration in the reject water. A co-fermentation process with flotate or flotate and vegetables increased biogas production compared to primary sludge by 162 and 180%, respectively. During the tests, there was no inhibition of the fermentation process. Hydrolysis of organic compounds contained in flotate and vegetables resulted in a significant increase in ammonium nitrogen (by 80–100%) and dissolved organic nitrogen concentration (by 170–180%). The biogas and methane production rate as well as the ammonium and total nitrogen release rate were calculated. An energy balance was made, which took into account the variable amount of electric energy production depending on the efficiency of the cogeneration systems and energy consumption for supplying oxygen necessary to remove nitrogen contained in the reject water. A positive energy balance was obtained for all analyses.

  • The Influence of Drying Temperature on Color Change of Hornbeam and Maple Wood Used as Surface and Inner Layers of Wood Composites
    • Ivan Klement
    • Peter Vilkovský
    • Tatiana Vilkovská
    • Kazimierz Orłowski
    • Jacek Barański
    • Daniel Chuchała
    • Aleksandra Suchta
    2021 Pełny tekst Applied Sciences-Basel

    The thermal treatment of wood changes its structure due to the degradation of wood polymers (cellulose, hemicellulose and lignin), so the physical properties of wood are either improved or degraded. Color changes apply not only to natural wood, but also to such wood composites for which some amount of glue is used in their construction (e.g., plywood, blockboard or laminboard). This article is focused on the analysis of hornbeam and field maple wood color changes influenced by drying temperature. Two types of drying modes were used: hot-air mode where the temperature of the drying environment was 60 C, and high-temperature mode with a drying temperature of 120 C. The drying mode was divided into two phases depending on the moisture content of the wood. The compared woods had similar values of color coordinates at the beginning of drying. During hot-air drying, the largest changes in color coordinates occurred during the first 24 h. The total color difference between the color at the end and the beginning of drying was 7.3 for hornbeam and 11.1 for maple. The overall color difference between the compared woods was minimal. During high-temperature drying (120 C), the color changes of the dried woods were more pronounced. In the case of maple wood, there was a very significant change in color and the value of DE* was twice as high as for hornbeam. The total color difference between the color at the end and at the beginning of drying was 8.7 for hornbeam and 18.9 for maple.

  • The Influence of External Additional Loading on the Muscle Activity and Ground Reaction Forces during Gait
    • Bartłomiej Zagrodny
    • Michał Ludwicki
    • Wiktoria Wojnicz
    2021 Pełny tekst Applied Bionics and Biomechanics

    Asymmetrical external loading acting on the usculoskeletal system is generally considered unhealthy. Despite this knowledge, carrying loads in an asymmetrical manner like carrying on one shoulder, with one hand, or on the strap across the torso is a common practice. This study is aimed at presenting the effects of the mentioned load carrying methods on muscle activity assessed by using thermal field and ground reaction forces. Infrared thermography and pedobarographic force platform (ground reaction force/pressure measurement) were used in this study. Experimental results point out an increased load-dependent asymmetry of temperature distribution on the chosen areas of torso and the influence of external loading on ground reaction forces. Results point out that wearing an asymmetrical load should be avoided and are showing which type of carrying the external load is potentially less and the most harmful.

  • The Influence of External Load on the Performance of Microbial Fuel Cells
    • Szymon Potrykus
    • León-Fernández Fernando Luis
    • Janusz Nieznański
    • Dariusz Karkosiński
    • Francisco-Jesus Fernandez-Morales
    2021 Pełny tekst ENERGIES

    In this work, the effect of the external load on the current and power generation, as well as on the pollutant removal by microbial fuel cells (MFCs), has been studied by step-wise modifying the external load. The load changes included a direct scan, in which the external resistance was increased from 120 Ω to 3300 Ω, and a subsequent reverse scan, in which the external resistance was decreased back to 120 Ω. The reduction in the current, experienced when increasing the external resistance, was maintained even in the reverse scan when the external resistance was step-wise decreased. Regarding the power exerted, when the external resistance was increased below the value of the internal resistance, an enhancement in the power exerted was observed. However, when operating near the value of the internal resistance, a stable power exerted of about 1.6 µW was reached. These current and power responses can be explained by the change in population distribution, which shifts to a more fermentative than electrogenic culture, as was confirmed by the population analyses. Regarding the pollutant removal, the effluent chemical oxygen demand (COD) decreased when the external resistance increased up to the internal resistance value. However, the effluent COD increased when the external resistance was higher than the internal resistance. This behavior was maintained in the reverse scan, which confirmed the modification in the microbial population of the MFC.

  • The influence of intermolecular correlations on the infrared spectrum of liquid dimethyl sulfoxide
    • Maciej Śmiechowski
    2021 Pełny tekst SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY

    Dimethyl sulfoxide (DMSO) is routinely applied as an excellent, water-miscible solvent and chemical reagent. Some of the most important data concerning its liquid structure were obtained using infrared (IR) spectroscopy. However, the actual extent of intermolecular correlations that connect the isolated monomer spectrum to the IR response of the bulk liquid is poorly studied thus far. Using ab initio molecular dynamics (AIMD) simulations, IR spectra of liquid DMSO are obtained here from first principles and further analyzed using an array of sophisticated spectral decomposition techniques. The calculated spectra when unfolded in space reveal non-trivial spatial correlations underlying the IR response of liquid DMSO. It is unequivocally demonstrated that some of the fundamental vibrations visible in the intramolecular limit are effectively suppressed by the solvation environment due to symmetry reasons and thus disappear in the bulk limit, escaping experimental detection. Overall, DMSO as an aprotic solvent with dominant dipole–dipole interactions displays strong intermolecular correlations that contribute significantly to the IR spectra, on par with the situation observed in strongly associated liquids, such as water.

  • The Influence of Loop Heat Pipe Evaporator Porous Structure Parameters and Charge on Its Effectiveness for Ethanol and Water as Working Fluids
    • Krzysztof Błauciak
    • Paweł Szymański
    • Dariusz Mikielewicz
    2021 Pełny tekst Materials

    Abstract: This paper presents the results of experiments carried out on a specially designed experimental rig designed for the study of capillary pressure generated in the Loop Heat Pipe (LHP) evaporator. The commercially available porous structure made of sintered stainless steel constitutes the wick. Three different geometries of the porous wicks were tested, featuring the pore radius of 1, 3 and 7 um. Ethanol and water as two different working fluids were tested at three different evaporator temperatures and three different installation charges. The paper firstly presents distributions of generated pressure in the LHP, indicating that the capillary pressure difference is generated in the porous structure. When installing with a wick that has a pore size of 1 um and water as a working fluid, the pressure difference can reach up to 2.5 kPa at the installation charge of 65 mL. When installing with a wick that has a pore size of 1 um and ethanol as a working fluid, the pressure difference can reach up to 2.1 kPa at the installation charge of 65 mL. The integral characteristics of the LHP were developed, namely, the mass flow rate vs. applied heat flux for both fluids. The results show that water offers larger pressure differences for developing the capillary pressure effect in the installation in comparison to ethanol. Additionally, this research presents the feasibility of manufacturing inexpensive LHPs with filter medium as a wick material and its influence on the LHP’s thermal performance.

  • The Influence of Nanometals, Dispersed in the Electrophoretic Nanohydroxyapatite Coatings on the Ti13Zr13Nb Alloy, on Their Morphology and Mechanical Properties
    • Michał Bartmański
    • Łukasz Pawłowski
    • Aleksandra Mielewczyk-Gryń
    • Gabriel Strugała
    • Krzysztof Rokosz
    • Sofia Gaiaschi
    • Patrick Chapon
    • Steinar Raaen
    • Andrzej Zieliński
    2021 Pełny tekst Materials

    In this work, nanohydroxyapatite coatings with nanosilver and nanocopper have been fabricated and studied. The presented results concern coatings with a chemical composition that has never been proposed before. The present research aims to characterize the effects of nanosilver and nanocopper, dispersed in nanohydroxyapatite coatings and deposited on a new, non-toxic Ti13Zr13Nb alloy, on the physical and mechanical properties of coatings. The coatings were obtained by a one-stage electrophoretic process. The surface topography, and the chemical and phase compositions of coatings were examined with scanning electron microscopy, atomic force microscopy, X-ray diffractometry, glow discharge optical emission spectroscopy, and energy-dispersive X-ray spectroscopy. The mechanical properties of coatings were determined by nanoindentation tests, while coatings adhesion was determined by nanoscratch tests. The results demonstrate that copper addition increases the hardness and adhesion. The presence of nanosilver has no significant influence on the adhesion of coatings.

  • The influence of selected strain-based failure criteria on ship structure damage resulting from a collision with an offshore wind turbine monopile
    • Karol Niklas
    • Alicja Bera
    2021 Pełny tekst Polish Maritime Research

    Offshore wind farms are developing well all over the world, providing green energy from renewable sources. The evaluation of possible consequences of a collision involves Finite Element computer simulations. The goal of this paper was to analyse the influence of selected strain-based failure criteria on ship damage resulting from a collision with an offshore wind turbine monopile. The case of a collision between an offshore supply vessel and a monopile-type support structure was examined. The results imply that simulation assumptions, especially the failure criteria, are very important. It was found that, using the strain failure criteria according to the minimum values required by the design rules, can lead to an underestimation of the ship damage by as much as 6 times, for the length of the hull plate, and 9 times, for the area of the ship hull opening. Instead, the adjusted formula should be used, taking into account both the FE element size and the shell thickness. The influence of the non-linear representation of the stress-strain curve was also pointed out. Moreover, a significant influence of the selected steel grade on collision damages was found.

  • The influence of the basic conditions of the forced feed of abrasive compound on the roughness of flat ceramic elements after lapping.
    • Adam Barylski
    • Maciej Gniot
    2021 Technologia i Automatyzacja Montażu

    W docieraniu standardowym zawiesina ścierna dostarczana jest do strefy obróbki w sposób ciągły - zalewowo lub kroplowo, co generuje duże straty ścierniwa. W artykule opisano innowacyjny system dozowania i nanoszenia zawiesiny ściernej na powierzchnię żeliwnego docieraka tarczowego, który eliminuje tą wadę. W przeprowadzonych eksperymentach badano wpływ procentowej zawartości ziaren ściernych w nośniku oraz wielkość dawki zawiesiny i lepkości nośnika płynnego na wartości poszczególnych parametrów chropowatości powierzchni docieranych elementów ceramicznych. Docieranie jest jedna z technologii stosowanej w montażu zespołów podczas zastosowania kompensacji technologicznej lb przy indywidualnym dopasowaniu składanych elementów.

  • The influence of the grid density of measurement points on damage detection in an isotropic plate by the use of elastic waves and laser scanning Doppler vibrometry
    • Łukasz Doliński
    • Marek Krawczuk
    • Magdalena Palacz
    • Wiktor Waszkowiak
    • Arkadiusz Żak
    2021 Pełny tekst SENSORS

    Damage detection in structural components, especially in mechanical engineering, is an 2 important element of engineering practice. There are many methods of damage detection, in which 3 changes in various parameters caused by the presence of damage are analysed. Recently, methods 4 based on the analysis of changes in dynamic parameters of structures, i.e. frequencies or mode shapes 5 of natural vibrations, as well as changes in propagating elastic waves, have been developed at the 6 highest rate. Diagnostic methods based on the elastic wave propagation phenomenon are becoming 7 more and more popular, therefore it is worth to focus on the improvement of the efficiency of these 8 methods. Hence, a question arises whether it is possible to shorten the required measurement time 9 without affecting the sensitivity of the diagnostic method used. This paper discusses the results 10 of research carried out by the authors in this regard both numerically and experimentally. The 11 numerical analysis has been carried out by the use of the Time-domain Spectral Finite Element 12 Method (TD-SFEM), whereas the experimental part has been based on the measurement performed 13 by 1-D Laser Doppler Scanning Vibrometery (LDSV).

  • The influence of the type of halogen substituent and its position on the molecular conformation, intermolecular interactions and crystal packing for a series of 1-benzoyl-3-(halogenophenyl)thioureas
    • Damian Rosiak
    • Andrzej Okuniewski
    • Jarosław Chojnacki
    2021 Pełny tekst Acta Crystallographica Section C-Structural Chemistry

    By the reaction of benzoyl chloride, potassium isothiocyanate and the appropriate halogenoaniline, i.e. 2/3/4-(bromo/iodo)aniline, we have obtained five new 1-benzoyl-3-(halogenophenyl)thioureas, namely, 1-benzoyl-3-(2-bromophenyl)- thiourea and 1-benzoyl-3-(3-bromophenyl)thiourea, C14H11BrN2OS, and 1-benzoyl-3-(2-iodophenyl)thiourea, 1-benzoyl-3-(3-iodophenyl)thiourea and 1-benzoyl-3-(4-iodophenyl)thiourea, C14H11IN2OS. Structural and conformational features of the compounds have been analyzed using X-ray diffraction and theoretical calculations. The novel compounds were characterized by solid-state IR and 1H/13C NMR spectroscopy. The conformations and intermolecular interactions, such as hydrogen bonds, pi–pi and S(6)... pi stacking, and X...O (X = Br or I) , I...S and I...pi, have been examined and rationalized, together with four analogous compounds described previously in the literature. The set of nine compounds was chosen to examine how a change of the halogen atom and its position on the phenyl ring affects the molecular and crystal structures.

  • The Influence of Tool Shape and Process Parameters on the Mechanical Properties of AW-3004 Aluminium Alloy Friction Stir Welded Joints
    • Anna Janeczek
    • Jacek Tomków
    • Dariusz Fydrych
    2021 Pełny tekst Materials

    The purpose of the following study was to compare the effect of the shape of a tool onthe joint and to obtain the values of Friction Stir Welding (FSW) parameters that provide the bestpossible joint quality. The material used was an aluminium alloy, EN AW-3004 (AlMn1Mg1). To theauthors’ best knowledge, no investigations of this alloy during FSW have been presented earlier. Fivebutt joints were made with a self-developed, cylindrical, and tapered threaded tool with a rotationalspeed of 475 rpm. In order to compare the welding parameters, two more joints with a rotationalspeed of 475 rpm and seven joints with a welding speed of 300 mm/min with the use of a cylindricalthreaded pin were performed. This involved a visual inspection as well as a tensile strength test ofthe welded joints. It was observed that the value of the material outflow for the joints made withthe cylindrical threaded pin was higher than it was for the joints made with the tapered threadedpin. However, welding defects in the form of voids appeared in the joints made with the taperedthreaded tool. The use of the cylindrical tool resulted in higher values for about 37% of mechanicalproperties compared with the highest result for the tapered threaded joint. As far as the parameterswere concerned, it was concluded that most of the specimens were properly joined for a rotationalspeed of 475 rpm. In the joints made with a welding speed of 300 mm/min, the material was notstirred properly. The best joint quality was given for a rotational speed of 475 rpm as well as a varietyof welding speed values between 150 and 475 mm/min.

  • The Influence of Water and Mineral Oil on Pressure Losses in Hydraulic Motor
    • Paweł Śliwiński
    • Piotr Patrosz
    2021

    In this paper, pressure losses in hydraulic motor supplied with water and mineral oil (two liquids that have significantly different viscosity and lubricating properties) are described and compared. The experimental tests were conducted using a hydraulic satellite motor that is dedicated to working with different liquids, including water. The methodology of measuring the pressure drop in internal channels of this motor is also described. The known mathematical formulas describing the pressure losses in the internal channels are presented also. Experimental studies have shown that a high flow rate in the motor causes the pressure losses in the motor supplied with water to be several percent greater than the pressure losses in the motor supplied with oil. However, low flow rates cause the pressure losses in the motor supplied with water to be about ten percent lower than the pressure losses in the motor supplied with oil. Furthermore, when the volume of the working chamber nears the minimum, additional pressure increase caused by compression of liquid occurs in this chamber.

  • The Interaction of Heptakis (2,6-di-O-Methyl)-β-Cyclodextrin with Mianserin Hydrochloride and Its Influence on the Drug Toxicity
    • Sylwia Belica-Pacha
    • Magdalena Małecka
    • Mateusz Daśko
    • Katarzyna Miłowska
    • Maria Bryszewska
    • Grażyna Budryn
    • Joanna Oracz
    • Bartłomiej Pałecz
    2021 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    One tetracyclic antidepressant, mianserin hydrochloride (MIA), has quite significant side effects on a patients’ health. Cyclodextrins, which are most commonly used to reduce the undesirable features of contained drugs within their hydrophobic interior, also have the potential to alter the toxic behavior of the drug. The present paper contains investigations and the characteristics of interaction mechanisms for MIA and the heptakis (2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD) system, and evaluated the effects of the complexation on MIA cytotoxicity. In order to assess whether there was an interaction between MIA and DM-β-CD molecules, isothermal titration calorimetry (ITC) have been chosen. Electrospray ionization mass spectrometry (ESI-MS) helped to establish the complex stoichiometry, and circular dichroism spectroscopy was used to describe the process of complex formation. In order to make a wider interpretative perspective, the molecular docking results have been performed. The viability of Chinese hamster cells were investigated in the presence of DM-β-CD and its complexes with MIA in order to estimate the cytotoxicity of the drug and the conjugate with the chosen cyclodextrin. The viability of B14 cells treated with MIA+DM-β-CD is lower (the toxicity is higher) than with MIA alone, and no protective effects have been observed for complexes of MIA with DM-β-CD in any ratio.

  • The interaction of the pulsed laser irradiation with titania nanotubes - Theoretical studies on the thermal effect
    • Piotr Kupracz
    • Katarzyna Grochowska
    • Jakub Wawrzyniak
    • Katarzyna Siuzdak
    2021 INTERNATIONAL JOURNAL OF THERMAL SCIENCES

    This paper reports temperature dispersion simulations of titania nanotubes irradiated by the 355 nm, pulsed, nanosecond laser. The modelling with the use of Finite Elements Method concerns titania nanotubes of the length and the wall thickness in the range of 0.5–2 μm and 5–20 nm, respectively. The uniqueness of the morphology was preserved by ensuring the wall thickness variation along the height of the tube, which was determined by an exponential equation. The easily adapted model of optical transition under the heat treatment in vacuum was successfully introduced. According to the obtained results, the change in titania nanotube shape and formation of the doping centres during laser annealing are crucial to accurately reproduce the temperature distribution along the nanotubes. The temperature profiles suggest that treatment with a fluence of 25 mJ cm−2 at 355 nm wavelength may lead to the re-solidification of the nanotubes surface only, if their wall is thinner than 15 nm. Such simulations are reported for the first time and are important for the understanding of thermal transport in nanomaterials with highly ordered, tubular architecture.

  • The Issue of Shading Photovoltaic Installation Caused by Dust Accumulation on the Glass Surface
    • Małgorzata Rudnicka
    • Ewa Klugmann-Radziemska
    2021 Pełny tekst Ecological Chemistry and Engineering S - Chemia i Inżynieria Ekologiczna S

    The issue of accumulation of dust and other pollutants on the surface of photovoltaic modules was thoroughly analysed over the years. One of the first surveys in this field of knowledge linked pollutant accumulation on the module surface with transmittance loss of its glass covering, which leads to lessened amount of solar radiation reaching solar cells. First stage of this accumulation process is linear transparency loss, and second stage - molecule agglomeration and settlement some grains on the already existing layer of dust. Additionally, the pace of working parameters reduction for photovoltaic installation is influenced by the type of dust itself. Molecules with smaller grains cover the surface much more densely, therefore limiting the amount of light passing though the top glass layer far more than molecules with bigger grains. The aim of the carried out study was to find the relationship between dust surface density and change in electrical parameters. Such approach makes it possible to compare electrical and physical parameters of different photovoltaic modules. Additionally, glass coverage itself was noted to have a significant impact on the overall decrease in working parameters of PV modules.