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Gdańsk University of Technology

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  • Impact of Climate Change on Water Sources and River‐Floodplain Mixing in the Natural Wetland Floodplain of Biebrza River
    • Tomasz Edward Berezowski
    • Daniel Partington
    2023 Full text WATER RESOURCES RESEARCH

    The origins of river and floodplain waters (groundwater, rainfall, and snowmelt) and their extent during overbank flow events strongly impact ecological processes such as denitrification and vegetation development. However, the long-term sensitivity of floodplain water signatures to climate change remains elusive. We examined how the integrated hydrological model HydroGeoSphere and the Hydraulic Mixing-Cell method could help us understand the long-term impact of climate change on water signatures and their spatial distribution in the protected Biebrza River Catchment in northeastern Poland. Our model relied on 20th century Reanalysis Data from 1881 to 2015 and an ensemble of EURO-CORDEX simulations for representative concentration pathways (RCP) 2.6, 4.5, and 8.5 from 2006 to 2099. The historical component of the simulations was subjected to extensive multiple-variable validation from 1881 to 2019. The results show that the extents of water sources were rather stable in the floodplain in the 1881–2015 period. The projected future impacts were variable with each analyzed RCP, but in all cases, different significant trends were present for the spatial distribution of water sources and for the river-floodplain mixing. However, the total volume of water from different sources was less sensitive to climate change than the dominant sources and spatial distribution of water. The simulation results highlight the impact of climate change on the extent of water sources in temperate zone wetlands with significant implications for ecological processes and management. These results also underscore the urgent need to leverage such modeling studies to inform protective and preservation strategies of floodplain wetlands.

  • Impact of laser beam welding on mechanical behaviour of 2.25Cr–1Mo (P22) steel
    • Sachin Sirohi
    • Shailesh M. Pandey
    • Vinita Tiwari
    • Dhowmya Bhatt
    • Dariusz Fydrych
    • Chandan Pandey
    2023 INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING

    The use of welding processes in the manufacturing and repair of structures intended for the energy industry plays a key role in the guarantee of a continuous supply of fossil fuels, which is the basic condition for ensuring energy security. A square butt joint of 10 mm thick plate of 2.25Cr–1Mo (P22) steel was fabricated by autogenous laser beam welding process and then post-weld heat treatment (PWHT) for two sets of process parameters (760 °C for 90 min–T1 and 730 °C for 180 min–T2). The joints were subjected to detailed metallographic investigations and hardness measurements, static tensile tests and impact toughness tests. The joint in as-welded state is characterized by significant heterogeneity of structural morphology and mechanical properties, while PWHT significantly improves uniformity in microstructure and mechanical properties along weldments. PWHT in particular causes tempering of the bainite and promotes the formation of carbide precipitates (M7C3, M23C6, and Mo2C) of globular and spherical shape along boundaries and bainite blocks. Laser welding caused a drastic increase in the weld metal hardness (388 HV) and coarse prior austenite grain bainite region (390 HV) compared to the hardness of base metal (BM) (below 200 HV). Both of the applied PWHT variants reduced the hardness of these areas of welded joints to the BM level. During the tensile tests, all the joints were fractured in BM. In the case of AW joints the tensile strength was higher than BM and it was 625 ± 10 MPa and after both PWHT, tensile strength was decreased by about 100 MPa. Due to over tempering of bainite in BM the elongation of the joints was several percentage points lower (27 ± 3 for AW joints) than the value for BM (35% ± 2), but slightly higher in the case of joints after PWHT (31 and 33 ± 1). Impact energy of the weld metal (259 ± 8 J) was lower than P22 base metal (320 ± 8 J), but PWHT causes a significant increase in impact energy of the weld metal (291 ± 6 J and 306 ± 10 J for T1 and T2, respectively). The analysis of these results shows that the proposed laser welding procedure with a high temperature gradient and PWHT enables the fabrication of P22 steel welded joints that meet the quality criteria.

  • Impact of rotor geometry optimization on the off-design ORC turbine performance
    • Łukasz Witanowski
    • Piotr Klonowicz
    • Piotr Lampart
    • Piotr Klimaszewski
    • Tomasz Suchocki
    • Łukasz Jędrzejewski
    • Dawid Zaniewski
    • Paweł Ziółkowski
    2023 ENERGY

    The paper describes the method of CFD based Nelder-Mead optimization of a 10 kW single-stage axial turbine operating in an ORC system working on R7100. The total-to-static isentropic efficiency is defined as an objective function. Multi-point linear regression is carried out to determine the significance of the objective function arguments and to pick up the set of particular variables and characteristic quantities (e.g. flow angles) which contribute most to improving the objective function value. This approach enables us to considerably reduce the number of optimized parameters and computational time needed for the optimization process. Variable operating parameters of ORC power systems become an everyday occurrence, which makes the analysis of ORC turbines under variable operating parameters a critical part of the design. Therefore, the paper presents the influence of a single-criterion optimization of the rotor geometry on the performance of the ORC turbine in a wide range of operating conditions. The results of optimization indicate that new geometry provides an approximately 5.5 pp. (percentage point) increase in total-to-static efficiency for the design point, and even larger improvements reaching 7 pp. For higher turbine loads, whereas for lower loads the efficiency improvements are at the level of 1.5–4 pp.

  • Impact of soluble organic matter and particulate organic matter on anammox system: Performance, microbial community and N2O production
    • Yingying He
    • Hongyu Mao
    • Jacek Mąkinia
    • Jakub Drewnowski
    • Bing Wu
    • Jun Xu
    • Li Xie
    • Xi Lu
    2023 JOURNAL OF ENVIRONMENTAL SCIENCES-CHINA

    In this study, the effects of soluble readily biodegradable COD (sCOD) and particulate slowly biodegradable COD (pCOD) on anammox process were investigated. The results of the longterm experiment indicated that a low sCOD/N ratio of 0.5 could accelerate the anammox and denitrification activity, to reach as high as 84.9% ±2.8% TN removal efficiency. Partial denitrification-anammox (PDN/anammox) and denitrification were proposed as the major pathways for nitrogen removal, accounting for 91.3% and 8.7% of the TN removal, respec- tively. Anammox bacteria could remain active with high abundance of anammox genes to maintain its dominance. Candidatus Kuenenia and Thauera were the predominant genera in the presence of organic matter. Compared with sCOD, batch experiments showed that the introduction of pCOD had a negative effect on nitrogen removal. The contribution of denitrification to nitrogen removal decreased from approximately 14% to 3% with increasing percentage of pCOD. In addition, the analysis result of the process data using an optimized ASM1 model indicated that high percentage of pCOD resulted in serious N 2 O emission (the peak value up to 0.25 mg N/L), which was likely due to limited mass diffusion and insufficient available carbon sources for denitrification. However, a high sCOD/N ratio was beneficial for alleviating N 2 O accumulation.

  • Impact of steel grade on a ship colliding with an offshore wind turbine monopile supporting structure
    • Karol Niklas
    • Alicja Bera
    • Yordan Garbatov
    2023 Full text OCEAN ENGINEERING

    Offshore wind power is experiencing rapid development around the world. The number of installations and their size is growing. Thousands of monopile support structures with diameters of 10 m and weights of 2000 tons will be installed in the coming years. Offshore wind power installations, often located close to the shore and shipping routes, pose a new challenge to ship safety. The study analyses the damages from an accidental collision between a 6500-tonne displacement Supply Offshore Vessel and the monopile support structure with a 10 m diameter and a 15 MW wind turbine. The head-on collision cases are performed according to the DNV-ST-0126, showing the consequences for the ship and the wind turbine support structure. In addition, simulation cases with an offset between the ship’s plane of symmetry and the monopile axis showed a new form of damage to the ship’s plating. During a head-on sliding collision, extensive plate tearing can occur due to its cutting at the deck line and concertina tearing under the pressure of the monopile. As a result, the hull may open over a large area, including the threat of unsealing the ship’s collision bulkhead. The S355 grade steel can significantly reduce collision damage by up to 50% (from 20.6 m2 to 10.5 m2 for the case studied here).

  • Impact of strontium non-stoichiometry of SrxTi0.3Fe0.7O3-δ on structural, electrical, and electrochemical properties for potential oxygen electrode of intermediate temperature solid oxide cells
    • Aleksander Mroziński
    • Sebastian Molin
    • Patryk Błaszczak
    • Tadeusz Miruszewski
    • Karolina Górnicka
    • Jakub Karczewski
    • Piotr Jasiński
    2023 Full text INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

    This work presents the results of a comprehensive study on the impact of the A-site non-stoichiometry of SrxTi0.3Fe0.7O3-δ (x = 0.90, 0.95, 1.00, 1.05) ceramics on their physicochemical properties. The materials were fabricated by the conventional solid-state reaction method and their structure was determined by X-ray diffractometry, X-ray photoelectron spectroscopy and electron microscopy. Their sintering and thermal expansion properties were then evaluated. The electrical properties of the materials were determined by electrical conductivity and electrical relaxation measurements (on bulk materials) and by electrochemical impedance spectroscopy (EIS) studies of symmetrical, CGO-electrolyte based, porous electrodes. Finally, fuel cell tests with the non-stoichiometric electrodes were evaluated. To elucidate the electrochemical reaction pathways for oxygen reduction/evolution reaction, EIS measurements were carried out in different pO2 and were analysed via the distribution of relaxation times method. The results showed a dependence of materials’ properties on the A-site non-stoichiometry, which can be used to fine-tune their properties, e.g. increase the surface exchange rate or decrease the thermal expansion coefficient.

  • Impact of temperature on optical sensing in biology based on investigation of SARS‐CoV ‐2
    • Małgorzata Szczerska
    • Paweł Wityk
    • Paulina Listewnik
    2023 Full text Journal of Biophotonics

    In this paper, we present an investigation of the influence of the temperature on the sensing of biological samples. We used biofunctionalized microsphere-based fiber-optic sensor to detect immunoglobulin G attached to the sensor head at temperatures relevant in biological research: 5°C, 25°C, and 55°C. The construction of the sensor allowed us to perform measurements in the small amount of solution. The results of our experiment confirm substantial changes in the measured reflected optical power, indicating the need to control the temperature during such measurements. The sensitivity of the sensor used in this research is 8.82 nW/°C. Coefficient R was also calculated and it equals 0.998, which shows good fit between theoretical linear fit and obtained measured data.

  • Impact of thermal backfill parameters on current-carrying capacity of power cables installed in the ground
    • Seweryn Szultka
    • Stanisław Czapp
    • Adam Tomaszewski
    2023 Full text Bulletin of the Polish Academy of Sciences-Technical Sciences

    Proper design of power installations with the participation of power cables buried in homogeneous and thermally well-conductive ground does not constitute a major problem. The situation changes when the ground is non-homogeneous and thermally low-conductive. In such a situation, a thermal backfill near the cables is commonly used. The optimization of thermal backfill parameters to achieve the highest possible current-carrying capacity is insufficiently described in the standards. Therefore, numerical calculations based on computational fluid dynamics could prove helpful for designers of power cable lines. This paper studies the influence of dimensions and thermal resistivity of the thermal backfill and thermal resistivity of the native soil on the current-carrying capacity of power cables buried in the ground. Numerical calculations were performed with ANSYS Fluent. As a result of the research, proposals were made on how to determine the current-carrying capacity depending on the dimensions and thermal properties of the backfill. A proprietary mathematical function is presented which makes it possible to calculate the cable current-carrying capacity correction factor when the backfill is used. The research is expected to fill the gap in the current state of knowledge included in the provisions of standards.

  • Implementacja aktów prawa w metodyce badań emisyjności akustycznej w transporcie szynowym
    • Roksana Licow
    • Natalia Karkosińska-Brzozowska
    • Anna Świerkoska
    • Wiktor Żółkoś
    • Przemysław Barszcz
    • Julia Szulta
    • Kamil Łukaszewicz
    • Izabela Muzyka
    • Aleks Gołąbek
    • Magdalena Jóźwik
    • Daria Kassin
    • Michał Polakowski
    • Mateusz Racki
    • Maciej Wolski
    • Bartosz Nowak
    2023

    Przedmiotem artykułu jest przedstawienie zakresu działań wraz ze wstępnymi wnioskami, które dotyczą realizowanego projektu Plutonium Supporting Student Research Teams pn. Badania emisyjności akustycznej w transporcie szynowym realizowanym przez Koło Naukowe Inżynierii Drogowej i Kolejowej Politechniki Gdańskiej. Celem projektu jest ocena emisyjności akustycznej typu nawierzchni z typem pojazdu szynowego oraz ocena komfortu podróżnych w transporcie kolejowym i tramwajowym w kontekście hałasu. Realizacja badań została zaplanowana dwutorowo:  pomiary zewnątrz pojazdu w kontekście zależności poziomu dźwięku w odniesieniu do określonych typów nawierzchni,  pomiary wewnątrz pojazdów w kontekście wpływu hałasu na komfort podróżnych. Zespół projektowy został podzielony na dwie grupy badawcze, jedna z grup działa w zakresie hałasu emitowanego przez pociągi, druga zaś hałasu emitowanego przez tramwaje. W artykule zawarto analizę literatury w tym norm oraz aktów prawnych dotyczących hałasu emitowanego we wewnątrz i na zewnątrz pojazdów szynowych. Analizę przeprowadzano dla pojazdów kolejowych oraz tramwajów. Na podstawie wniosków opracowano szereg metodyk prowadzenia badań akustycznych celem implementacji ich w realizacji eksperymentów na rzeczywistych obiektach podczas ich eksploatacji. Opracowana metodyka badań może być podstawą do zmian prawnych w sposobach i metodach oceny hałasu na zewnątrz i przede wszystkim wewnątrz pojazdów szynowych np. z uwzględnieniem różnych typów wagonów.

  • Implementation of an Adaptive Method for Changing the Frequency Division of the Counter Clock Signal in a Frequency-to-Code Converter
    • Dariusz Świsulski
    • Piotr Warda
    2023 Full text ENERGIES

    Processing physical quantities into an indirect signal is a standard method of transferring information about the measured quantity to the master system, which analyzes the data obtained from the acquisition system. The intermediate signal is very often the voltage, but another transmission medium can be the frequency of the output signal of the “physical quantity-to-frequency” converter. The article presents the implementation of the adaptive method of selecting the clock signal frequency of the counter working in the converter. The issue of selecting the clock signal frequency for the required processing range of the transducer is discussed in detail. The application of the method using the STM32L476RG microcontroller is presented. The principle of checking the processing range of the developed transducer model is discussed. The algorithms of transducer operation in basic and adaptive modes of measuring the period of the variable frequency signal are proposed. The results of operation, in both modes, of the transducer model of frequency processing are presented, along with the metrological analysis of the results. The influence of selected approximations used to reconstruct the measured quantity on the final presentation of the measurement result is discussed.

  • Implementation of IMS/NGN Transport Stratum Based on the SDN Concept
    • Sylwester Kaczmarek
    • Maciej Sac
    • Kamil Bachorski
    2023 Full text SENSORS

    The paper presents the development and verification of software and a testbed aiming to demonstrate the ability of two telecommunication network concepts—Next Generation Network (NGN) and Software-Defined Networking (SDN)—to cooperate. The proposed architecture includes components of the IP Multimedia Subsystem (IMS) in its service stratum and of the SDN (controller and programmable switches) in its transport stratum, providing flexible transport resource control and management via open interfaces. One important feature of the presented solution is the inclusion of ITU-T standards for NGN networks, which are not considered in other related works. The paper includes details regarding the hardware and software architecture of the proposed solution as well as results of the performed functional tests, which confirm its proper operation.

  • IMPLEMENTING THE QUALITY ASSURANCE SYSTEM AND ASSURING HEALTH SAFETY IN THE LIGHT OF INCREASING BREAD QUALITY
    • Radosław Drozd
    • Radosław Wolniak
    2023 Full text Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

    The article presents rules, requirements, and norms for quality management and health safety assurance systems among small and medium bakeries. This group of businesses does not have the obligation of implementing or certifying specific systems. They are, however, implemented in order to increase the quality of the bread or reach a better market position. Also, the results of a 2022 study of 53 bakeries’ implementation of individual quality management systems are presented in the paper. The study shows an important role of the implementation of coordinated systems in the increase of quality of bread. Theoretical considerations and the results of a questionnaire study allowed the author to discuss and explain why neither the TQM system nor the BRC standards were implemented in small- and medium- sized bakeries. The results of research on the implementation of quality management systems and ensuring the health safety of bread confirm the legitimacy of using integrated quality systems. They will have a fundamental impact in the long-term perspective of innovative management of bakery managers and owners.

  • Improved methods for stator end winding leakage inductance calculation
    • Grzegorz Kostro
    • Michał Michna
    • Filip Kutt
    • Roland Ryndzionek
    2023 Full text COMPEL-THE INTERNATIONAL JOURNAL FOR COMPUTATION AND MATHEMATICS IN ELECTRICAL AND ELECTRONIC ENGINEERING

    Calculating the stator end-winding leakage inductance, taking into account the rotor, is difficult due to the irregular shape of the end-winding. The end-winding leakage may distribute at the end of the active part and the fringing flux of the air gap. The fringing flux belongs to the main flux but goes into the end-winding region. Then, not all the magnetic flux occurring in the end region is the end-winding leakage flux. The purpose of this paper was to find a method to accurately separate the leakage from the total flux, taking into account the rotor.

  • Improved-Efficacy EM-Driven Optimization of Antenna Structures Using Adaptive Design Specifications and Variable-Resolution Models
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2023 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION

    Optimization-driven parameter tuning is an essential step in the design of antenna systems. Although in many cases it is still conducted through parametric studies, rigorous numerical methods become a necessity if truly optimum designs are sought for, and the problem intricacies (number of variables, multiple goals, constraints) make the interactive approaches insufficient. The two practical considerations of electromagnetic (EM)-driven optimization are reliability and computational cost. Repetitive EM simulations may incur unmanageable expenses, whereas the lack of a decent starting point or objective function multimodality may prevent the numerical procedures (especially the local ones) from identifying satisfactory designs. In pursuit of reliability improvements, a design specification adjustment procedure has been recently proposed that improves the immunity of local search procedures to poor starting points. Therein, the objective function is modified by relocating the design goals (e.g., center frequencies) closer to the actual operating parameters of the antenna at the current design, to make them attainable through local search. The goals are then gradually adjusted and converge to the original targets towards then end of the optimization process. In this paper, we introduce an algorithm for reliable and low-cost antenna tuning that capitalizes on the specification management scheme while embedding it in variable-resolution optimization framework. In our approach, the EM model fidelity is adaptively adjusted based on the misalignment between the actual and target operating conditions, as well as the convergence status of the algorithm. By initiating the search process from the lowest-fidelity model (gradually dialed up to the highest-fidelity one), considerable computational savings of almost sixty percent can be achieved, with respect to the single-fidelity procedure. The speedup is possible without compromising reliability of the optimization process, as demonstrated using three examples of microstrip antennas, designed under different and challenging scenarios.

  • Improvement of speech intelligibility in the presence of noise interference using the Lombard effect and an automatic noise interference profiling based on deep learning
    • Krzysztof Kąkol
    2023 Full text

    The Lombard effect is a phenomenon that results in speech intelligibility improvement when applied to noise. There are many distinctive features of Lombard speech that were recalled in this dissertation. This work proposes the creation of a system capable of improving speech quality and intelligibility in real-time measured by objective metrics and subjective tests. This system consists of three main components: speech type detection, noise profiling, and an adaptive strategy of selection the modification. The role of the first component is to detect the Lombard speech in the input signal to avoid unnecessary speech modifications when the speech is naturally Lombard in its character. The second module is noise profiling, as the type of noise strongly impacts the selection of the best modification. The last part of the system is the adaptive modification selection component. The selection is made based on the speech signal features, resulting in the most considerable speech quality improvement, measured with objective metrics. To solve the problem posed, machine learning was used in this dissertation – especially deep learning with convolutional neural networks and typical multilayer networks. It was proven that it is possible to create an adaptive system that would improve speech quality in the presence of noise in real-time or near real-time.

  • Improving carbon dioxide capture in aqueous ammonia solutions by fine SiO2 particles
    • Donata Konopacka-Łyskawa
    • Temesgen Amibo
    • Dominik Dobrzyniewski
    • Marcin Łapiński
    2023 Full text Chemical and Process Engineering : New Frontiers

    Ammonia solutions are considered to be effective solvents for carbon dioxide absorption. Despite the numerous advantages of these solvents, their high volatility is a significant technical and economic problem. Therefore, in this work, silica particles were used as additives to improve CO2 absorption and inhibit NH3 desorption. SiO2 microparticles and colloidal SiO2 particles in the concentration range of 0-0.15 wt.% were used in this study. The most favorable mass transport for CO2 absorption was at the concentration of colloidal particles of 0.05 wt.%. Under these conditions, the enhancement in the number of moles of absorbed CO2 was above 30%. However, in solvents containing 0.01 wt.% SiO2 microparticles, the increase in CO2 absorption was about 20%. At the same time, the addition of SiO2 particles significantly reduced the escape of ammonia from the solution. The best improvement was obtained when colloidal SiO2 particles were added, and then NH3 escape was decreased by about 60%. This unfavorable phenomenon was also inhibited in ammonia solutions containing SiO2 microparticles at a concentration of 0.01 wt.%.

  • In situ transformation boosts the pseudocapacitance of CuNi-MOF via cooperative orientational and electronic governing
    • Xianyu Chu
    • Fanling Meng
    • Wei Zhang
    • Lihua Zhang
    • Sebastian Molin
    • Piotr Jasiński
    • Weitao Zheng
    2023 Full text Materials Research Letters

    The disordered arrangement and thereof inferior conductivity of 2D MOF sheets seriously hinder their practical application. Herein, we propose in situ transformation strategy to architect vertically oriented bimetallic CuNi-MOF as a self-supporting electrode, leading to a decuple high specific capacitance of 1262 C g-1 in comparison with the pristine Ni-MOF powder of 114 C g-1 at 2 A g-1. DFT calculations reveal that introduction of Cu can modulate the electronic structure of metal centers in the Ni-MOF sheets and optimize electrical conductivity. Our strategy is promising to maximize the utilization of MOF superiorities for optimizing their electrochemical performance.

  • In vitro and in silico assessment of anti-inflammatory activity of cocoa powders
    • Jelena S. Katanić Stanković
    • Vanja Todorović
    • Jelena Dorović Jovanović
    • Zoran Marković
    • Sanja Krstić
    • Nevena Dabetić
    • Sladana Sobajić
    • Agnieszka Bartoszek-Pączkowska
    • Zoran Maksimovic
    • Rudolf Bauer
    2023

    Plants are considered the major sources of biologically active compounds, which provide unlimited opportunities for their use either as medical treatments or as novel drug formulations. Cocoa powder is frequently used in nutrition and is known to have many benefits thanks to its wide range of biological activities. The presented study was focused on th evaluation of the anti-inflammatory potential of extracts obtained from cocoa powder. In vitro assays were employed to evaluate the level of inhibition of cyclooxygenases-1 and -2 activities (COX-1 and COX-2) by tested extracts. Molecular docking was used for in silico prediction of cyclooxygenase isoforms inhibition by selected cocoa powder constituents. The results showed that all tested extracts exerted much higher potential in inhibiting COX-2 activity and may be considered in use as selective inhibitors of COX-2 enzyme. On the other hand, in silico study shows quercetin and clovamide as the compounds with the highest potential to inhibit both COX-1 and COX-2.

  • In Vitro and In Vivo Imaging-Based Evaluation of Doxorubicin Anticancer Treatment in Combination with the Herbal Medicine Black Cohosh
    • Agata Płoska
    • Marcin Woźniak
    • Jamila Hedhli
    • Christian J. Konopka
    • Antonios Skondras
    • Sarah Matatov
    • Andrew Stawarz
    • Sarah Schuh
    • Andrzej Czerwinski
    • Lawrence W. Dobrucki
    • Leszek Kalinowski
    • Iwona T. Dobrucki
    2023 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    As a substitution for hormone replacement therapy, many breast cancer patients use black cohosh (BC) extracts in combination with doxorubicin (DOX)-based chemotherapy. In this study, we evaluated the viability and survival of BC- and DOX-treated MCF-7 cells. A preclinical model of MCF-7 xenografts was used to determine the influence of BC and DOX administration on tumor growth and metabolism. The number of apoptotic cells after incubation with both DOX and BC was significantly increased (~100%) compared to the control. Treatment with DOX altered the potential of MCF-7 cells to form colonies; however, coincubation with BC did not affect this process. In vivo, PET-CT imaging showed that combined treatment of DOX and BC induced a significant reduction in both metabolic activity (29%) and angiogenesis (32%). Both DOX and BC treatments inhibited tumor growth by 20% and 12%, respectively, and combined by 57%, vs. control. We successfully demonstrated that BC increases cytotoxic effects of DOX, resulting in a significant reduction in tumor size. Further studies regarding drug transport and tumor growth biomarkers are necessary to establish the underlying mechanism and potential clinical use of BC in breast cancer patients.

  • In vitro enzyme kinetics and NMR-based product elucidation for glutathione S-conjugation of the anticancer unsymmetrical bisacridine C-2028 in liver microsomes and cytosol: major role of glutathione S-transferase M1-1 isoenzyme
    • Agnieszka Potęga
    • Dominika Rafalska
    • Dawid Kazimierczyk
    • Michał Kosno
    • Aleksandra Pawłowicz
    • Witold Andrałojć
    • Ewa Paluszkiewicz
    • Tomasz Laskowski
    2023 Full text MOLECULES

    This work is the next step in studying the interplay between C-2028 (anticancer-active unsymmetrical bisacridine developed in our group) and the glutathione S-transferase/glutathione (GST/GSH) system. Here, we analyzed the concentration- and pH-dependent GSH conjugation of C-2028 in rat liver microsomes and cytosol. We also applied three recombinant human GST isoenzymes, which altered expression was found in various tumors. The formation of GSH S-conjugate of C-2028 in liver subfractions followed Michaelis-Menten kinetics. We found that C-2028 was conjugated with GSH preferentially by GSTM1-1, revealing a sigmoidal kinetic model. Using a colorimetric assay (MTT test), we initially assessed the cellular GST/GSH-dependent biotransformation of C-2028 in relation to cytotoxicity against Du-145 human prostate cancer cells in the presence or absence of the modulator of GSH biosynthesis. Pretreatment of cells with buthionine sulfoximine resulted in a cytotoxicity decrease, suggesting a possible GSH-mediated bioactivation process. Altogether, our results confirmed the importance of GSH conjugation in C-2028 metabolism, which humans must consider when planning a treatment strategy. Finally, nuclear magnetic resonance spectroscopy elucidated the structure of the GSH-derived product of C-2028. Hence, synthesizing the compound standard necessary for further advanced biological and bioanalytical investigations will be achievable.

  • Incorporating installation effects into the probability analysis of controlled modulus columns
    • Jakub Konkol
    2023 Full text SOILS AND FOUNDATIONS

    This technical report presents the probabilistic analysis which integrates the Monte Carlo simulation (MCS) with random field theory to model the load–displacement behavior of Controlled Modulus Columns (CMCs) in overconsolidated Poznań clay. Presented study focuses on the practical aspects of statistical analysis of geotechnical data, numerical model development, and results evaluation. Variability and spatial distribution of geotechnical parameters are based directly on field and lab testing. The inherent variability of soil parameters obtained from geotechnical investigation at the site is similar to the values reported in worldwide datasets for clays. The extensive discussion about incorporation of installation effects into numerical modelling is made. It was found that proper incorporation of installation effects is governed by correct estimation of initial stress level and interface shear strength parameters. The Anisotropic Undrained Shear Strength (AUS) model which captures nonlinear behavior and anisotropy of soil (Krabbenhøft et al., 2019) is a good choice to model overconsolidated clay in intact and interface zones. The application of total stress approach, the AUS model, installation effects, and natural (inherent) variability of soil and interface parameters is sufficient to explain differences in CMC load – displacement behavior observed in the field.

  • Increasing the conductivity of V2O5-TeO2 glass by crystallization: structure and charge transfer studies
    • Piotr Okoczuk
    • Natalia Wójcik
    • Leon Murawski
    • Leszek Wicikowski
    • Marcin Łapiński
    • Piotr Winiarz
    • Barbara Kościelska
    2023 Full text JOURNAL OF MATERIALS SCIENCE

    In the present paper, V 2 O 5 -TeO 2 glass was prepared by the melt-quenching technique. Crystallization of glass with a vanadium content higher than 35%mol results in an increase in electrical conductivity by a few orders of magnitude and a decrease in activation energy from ~0.40 to ~0.12 eV. In this work, a critical review of existing charge transfer models was presented on the example of V 2 O 5 -TeO 2 glass and glass–ceramics. Schnakenberg’s and Friedman-Triberis’ charge transfer models were found to be applicable to both glass and glass–ceramics. Optical phonon frequencies obtained from Schnakenberg’s model are in agreement with FTIR studies. Values of activation energies obtained from the Schnakenberg model decrease after crystallization. Friedman-Triberis’ model shows an increase in the density of states near the Fermi level from 10 ¹⁹ eV ⁻¹ cm ⁻³ in glass, to 10 ²¹ eV ⁻¹ cm ⁻³ in glass ceramics. Structural studies show that the main crystallizing phase is Te 2 V 2 O 9 which occurs with the V 2 O 5 shell in glasses with compositions 50–50%mol and 45–55%mol. It is concluded that crystallization results in the reduction of vanadium ions in the remaining glass matrix which leads to an increase in the V ⁴⁺ /V ⁵⁺ ratio and therefore, an increase in electrical conductivity.

  • Increasing the Utilization of dc-link Voltage of a Five-Leg VSI Based on Rotor Angle Control of Dual Induction Motors
    • Dmytro Kondratenko
    • Arkadiusz Lewicki
    • Charles Odeh
    2023 Full text

    This paper introduces an increased utilization of the dc-link voltage of a five-leg voltage source inverter (VSI) based on the rotor flux angle control technique for dual induction motors, IM. The main purpose is to utilize additional abilities provided by a multi-motor drive system in limited operating conditions. Generally, a multi-motor drive system is widely used in electric vehicles (EVs), traction systems and in several industrial applications. A dual IM drive system is investigated in this paper, where field-oriented control (FOC) scheme and space vector pulse-width modulation (SVPWM) technique are used for the drives control. Therein, additional rotor angle control is implemented to increase the maximum modulation index. The proposed control technique allows the control of two independent three-phase IM. Under limited conditions, both motors can achieve high modulation index values and decreased losses as well. Simulation studies and results carried out in PLECS software package show the effectiveness and feasibility of the proposed control strategy. Experimental results presented proved the idea of the proposed solution.

  • Indole-Acrylonitrile Derivatives as Potential Antitumor and Antimicrobial Agents—Synthesis, In Vitro and In Silico Studies
    • Anita Kornicka
    • Karol Gzella
    • Katarzyna Garbacz
    • Małgorzata Jarosiewicz
    • Maria Gdaniec
    • Joanna Fedorowicz
    • Lukasz Balewski
    • Jakub Kokoszka
    • Anna Ordyszewska
    2023 Full text Pharmaceuticals

    A series of 2-(1H-indol-2-yl)-3-acrylonitrile derivatives, 2a–x, 3, 4a–b, 5a–d, 6a–b, and 7, were synthesized as potential antitumor and antimicrobial agents. The structures of the prepared compounds were evaluated based on elemental analysis, IR, 1H- and 13NMR, as well as MS spectra. X-ray crystal analysis of the representative 2-(1H-indol-2-yl)-3-acrylonitrile 2l showed that the acrylonitrile double bond was Z-configured. All compounds were screened at the National Cancer Institute (USA) for their activities against a panel of approximately 60 human tumor cell lines and the relationship between structure and in vitro antitumor activity is discussed. Compounds of interest 2l and 5a–d showed significant growth inhibition potency against various tumor cell lines with the mean midpoint GI50 values of all tests in the range of 0.38-7.91 mM. The prominent compound with remarkable activity (GI50 = 0.0244-5.06 mM) and high potency (TGI = 0.0866-0.938 mM) against some cell lines of leukemia (HL-60(TB)), non-small cell lung cancer (NCI-H522), colon cancer (COLO 205), CNS cancer (SF-539, SNB-75), ovarian cancer ((OVCAR-3), renal cancer (A498, RXF 393), and breast cancer (MDA-MB-468) was 3-[4-(dimethylamino)phenyl]-2-(1-methyl-1H-indol-2-yl)acrylonitrile (5c). Moreover, the selected 2-(1H-indol-2-yl)-3-acrylonitriles 2a–c and 2e–x were evaluated for their antibacterial and antifungal activities against Gram-positive and Gram-negative pathogens as well as Candida albicans. Among them, 2-(1H-indol-2-yl)-3-(1H-pyrrol-2-yl)acrylonitrile (2x) showed the most potent antimicrobial activity and therefore it can be considered as a lead structure for further development of antimicrobial agents. Finally, molecular docking studies as well as drug-likeness and ADME profile prediction were carried out.

  • INDUSTRIAL HERITAGE IN “SACRIFICE ZONES”. THE POTENTIAL OF BOCAMINA I & II THERMOELECTRIC IN CORONEL, CHILE
    • Karolina Krośnicka
    • Miguel Angel Delso Páez
    2023 Full text Przestrzeń Ekonomia Społeczeństwo

    This work aims to present the recovery potential of the Chilean Sacrifice Zones, urban areas affected by high amounts of pollution caused by industrial activities. It centers in the case of “Bocamina I & II”, two Thermoelectric based in the city of Coronel, southern Chile. A settlement historically related to the mining processes. These plants operated for decades supplying the national energy grid and are seen as both symbols of progress and detriment. As part of the government Energy Transition Plan, they were recently closed for more sustainable energy sources and though the decision is seen as a national milestone, not much has been said regarding the buildings themselves. This research contextualizes the case of study, elaborates on how its future use and perception could help mitigate the negative impact on its surroundings and how the case can be extrapolated to similar cases internationally. For this, the work focuses on the plant’s infrastructure, their relation to the immediate context of Coronel and importance to Chilean industrial history on two approaches: Analyzing the alternative of their classification as National Monuments by the Chilean National Monuments Council, and by the Adaptive reuse approach, internationally seen as a sustainable strategy for abandoned buildings. Different arguments and examples are presented with the purpose of providing an understanding of the potential of Industrial Heritage reclamation, and how it could change the perception of the Sacrifice Zones through community involvement, urban planning, collaborative design and identity empowerment.

  • Industry-level analysis of COVID-19’s impact in emerging markets – evidence from Pakistan
    • Muhammad Mushafiq
    2023 International Journal of Emerging Markets

    Purpose – The main purpose of this study is to evaluate COVID-19’s impact on the emerging stock markets. Design/methodology/approach – To evaluate the influence of COVID-19, this study uses a novel method of event study methodology to measure the impact of COVID-19 on emerging stock markets. The research’s sample includes a total of 79 firms from 26 industries that are included in the KSE-100 Index from the Pakistan Stock Exchange. Three events were studied: (1) Announcement of the first case, (2) Start of lockdown and (3) End of lockdown. Findings – This study establishes the findings that industries in the Pakistan Stock Exchange were overall negatively affected by the COVID-19. Commercial banks, Insurance, Real Estate and Textile were badly affected by the COVID-19. However, the Pharmaceutical, Refinery and Food and Personal Care Products industries had shown a positive response. Practical implications – This study could bring in a new and useful insight into the literature on the impact of COVID-19 on the emerging stock markets. The results of this study provide insight to the investors in the emerging stock markets of the industries that are likely to show responses either negative or positive to news of regional or global outbreaks, lockdowns and end of lockdowns. Originality/value – The work on COVID-19 has been mostly limited to the developed markets and the emerging markets have been overlooked. This study is a potential gateway to future works regarding pandemics in emerging markets.

  • Indywidualna wystawa "Tylko ból jest mój" (1.12.2023 - 18.04.2024)
    • Edyta Urwanowicz
    2023

    Ekspozycja przygotowana przez kobiety – o kobietach. O tym, jak wyglądał ich Sybir i jak one go zapamiętały. Będzie pobudzać do refleksji nad pytaniami: Co znaczyło być kobietą na Sybirze? Jakie trudności spadały na kobiety, które znalazły się w sytuacji granicznej? Wreszcie – czy kobiecie doświadczonej przez przemoc pozostaje tylko ból?

  • Influence of Actual Curing Conditions on Mechanical Properties of Concrete in Bridge Superstructures
    • Jakub Krząkała
    • Piotr Łaziński
    • Michael Gerges
    • Łukasz Pyrzowski
    • Grzegorz Grządziela
    2023 Full text Materials

    This article presents the research on the mechanical characteristics of concrete in the construction of three concrete bridges. A system of recording the internal temperature of concrete and automatic control of laboratory ovens was used for specimen curing. This allowed the specimens to be cured under conditions similar to those occurring in the structure. Before the construction, reference blocks were used to define similar curing conditions. Maximum setting temperatures ranged from 47.6 _C to 62.0 _C and had a favorable effect on the properties of the concrete at an early age. For concretes with the use of CEM I cement, after 3 days of curing, the strength obtained was up to 8.2 MPa (23%) higher than that for specimens cured under standard conditions. The modulus of elasticity was higher up to 4.9 GPa (21%). For concrete with the use of CEM III cement, these differences were 26.9 MPa (174%) and 10.3 GPa (64%), respectively. After 7 days of curing, the results were close to each other and after 14, 28, and 56 days, higher values were obtained for specimens cured under standard conditions. The value of the modulus of elasticity of concrete was determined using the direct method according to Eurocode and the standard A method. A test load of the bridge was carried out to verify the modulus values obtained from laboratory tests. The highest consistency (99%) between the theoretical deflections and those measured in the test load was achieved when using the stabilized modulus values obtained on specimens cured under structure conditions in the FEM model. The research confirms the necessity of determining the mechanical characteristics of concrete with taking into account the curing conditions of concrete in the structure. A procedure for determining the mechanical properties of concrete for the correct construction of a bridge is proposed. These results can also be used in the development of a digital twin for bridge management.

  • Influence of Added Water Mass on Ship Structure Vibration Parameters in Virtual and Real Conditions
    • Do Van Doan
    • Lech Murawski
    • Adam Szeleziński
    • Tomasz Muchowski
    • Marcin Kluczyk
    • Adam Muc
    • Krzysztof Jasiński
    • Marek Chodnicki
    2023 Full text Scientific Journal of Gdynia Maritime University

    Modelling of ship structures in a virtual environment is now standard practice. Unfortunately, many engineers forget to consideri the influence of added water on the frequency values and the amplitude of natural vibrations. The article presents the effect of water damping on the frequency values of the individual natural vibration modes. The tests were carried out in two stages. First, the mentioned values were determined using FEM and then the values obtained in this way were compared with the parameters measured during laboratory tests. For the needs of laboratory measurements, structural elements made of ship steel in one of the Polish shipyards were used. All welds of the test objects have been verified in terms of their correctness. Irregularities in the execution of welded joints could result in a measurement error that is difficult to identify. As a result of the tests, the percentage differences in the frequency of occurrence of natural vibrations of individual modes were determined according to added water mass considerations. Importantly, the research concerned a real structural element of the hull, and the results obtained confirm the need to take into account the mass of accompanying water during the hull's FEM analysis. A number of more detailed research results were obtained, the most important of which is the fact that the finite element method is a valuable method for assessing the dynamics of wetted structures: the error in determining the vibration frequency did not exceed 5% for basic modes. The method of modelling the tested structures was almost equally important: the discrepancy of the results reached 4% depending on the modelling method. When designing marine SHM systems, it is essential to consider the effect of added water mass, since the frequency variations of a damaged structure, in relation to an undamaged one, are of the same order as the effect of added water.

  • Influence of algorithmic management practices on workplace well-being – evidence from European organisations
    • Hanna Kinowska
    • Łukasz Sienkiewicz
    2023 Full text Information Technology & People

    Purpose Existing literature on algorithmic management practices –defined as autonomous data-driven decision making in people's management by adoption of self-learning algorithms and artificial intelligence – suggests complex relationships with employees' well-being in the workplace. While the use of algorithms can have positive impacts on people-related decisions, they may also adversely influence job autonomy, perceived justice and – as a result – workplace well-being. Literature review revealed a significant gap in empirical research on the nature and direction of these relationships. Therefore the purpose of this paper is to analyse how algorithmic management practices directly influence workplace well-being, as well as investigating its relationships with job autonomy and total rewards practices. Design/methodology/approach Conceptual model of relationships between algorithmic management practices, job autonomy, total rewards and workplace well-being has been formulated on the basis of literature review. Proposed model has been empirically verified through confirmatory analysis by means of structural equation modelling (SEM CFA) on a sample of 21,869 European organisations, using data collected by Eurofound and Cedefop in 2019, with the focus of investigating the direct and indirect influence of algorithmic management practices on workplace well-being. Findings This research confirmed a moderate, direct impact of application of algorithmic management practices on workplace well-being. More importantly the authors found out that this approach has an indirect influence, through negative impact on job autonomy and total rewards practices. The authors observed significant variation in the level of influence depending on the size of the organisation, with the decreasing impacts of algorithmic management on well-being and job autonomy for larger entities.

  • Influence of CeO2 and TiO2 Particles on Physicochemical Properties of Composite Nickel Coatings Electrodeposited at Ambient Temperature
    • Iryna Makarava
    • Mohammadamin Esmaeili
    • Dmitry Kharitonov
    • Leonardo Pelcastre
    • Jacek Ryl
    • Mohammad Reza Bilestan
    • Esa Vuorinen
    • Eveliina Repo
    2023 Full text Materials

    The Ni-TiO2 and Ni-CeO2 composite coatings with varying hydrophilic/hydrophobic characteristics were fabricated by the electrodeposition method from a tartrate electrolyte at ambient temperature. To meet the requirements of tight regulation by the European Chemicals Agency classifying H3BO3 as a substance of very high concern, Rochelle salt was utilized as a buffer solution instead. The novelty of this study was to implement a simple one-step galvanostatic electrodeposition from the low-temperature electrolyte based on a greener buffer compared to traditionally used, aiming to obtain new types of soft-matrix Ni, Ni-CeO2, and Ni-TiO2 coatings onto steel or copper substrates. The surface characteristics of electrodeposited nickel composites were evaluated by SEM, EDS, surface contact angle measurements, and XPS. Physiochemical properties of pure Ni, Ni-CeO2, and Ni-TiO2 composites, namely, wear resistance, microhardness, microroughness, and photocatalytic activity, were studied. Potentiodynamic polarization, EIS, and ICP-MS analyses were employed to study the long-term corrosion behavior of coatings in a 0.5 M NaCl solution. Superior photocatalytic degradation of methylene blue, 96.2% after 6 h of illumination, was achieved in the case of Ni-TiO2 composite, while no substantial change in the photocatalytic behavior of the Ni-CeO2 compared to pure Ni was observed. Both composites demonstrated higher hardness and wear resistance than pure Ni. This study investigates the feasibility of utilizing TiO2 as a photocatalytic hydrophilicity promoter in the fabrication of composite coatings for various applications.

  • Influence of controlled crystallization and SrF2 content on the structure and properties of Eu3+ doped phosphate glasses
    • Michał Maciejewski
    • Karolina Milewska
    • Anna Synak
    • Wojciech Sadowski
    • Barbara Kościelska
    2023 JOURNAL OF NON-CRYSTALLINE SOLIDS

    New phosphate glasses and glass-ceramics P2O5–Bi2O3–K2O–Nb2O5-SrF2 doped with Eu were synthesized and studied in this work. The influence of the SrF2 content (0–15 mol%) and the parameters of the heat treatment on their structural and optical properties were investigated. For the above purpose, the structural characterization by FTIR spectroscopy and XRD measurements was carried out, which showed a significant effect of SrF2 on the obtained crystal phases and the structure of the glass matrix. The results of combined DSC/DTA techniques enabled the determination of thermal properties and complemented the investigated crystallization characteristics of the glasses. Based on the measurements of the luminescence properties and the decay curves, it was confirmed that the Eu3+ ions were partially incorporated into the crystallites embedded in the glass matrix, which resulted in a significant enhancement of the luminescence. The conducted research confirms that the presented materials are a promising candidate for resistant phosphors in visible LEDs.

  • Influence of cyclic frozen and defrost on mechanical properties of polytetrafluoroethylene (PTFE)-coated woven fabrics
    • Andrzej Ambroziak
    • Paweł Kłosowski
    2023 Full text Archives of Civil Engineering

    This research aims to determine the influence of the cyclic process of freezing and defrosting on the mechanical properties of the chosen glass fibres and PTFE-coated woven fabrics. The specimens were subjected to freezing at about −20 °C for 4 h and thawing by full immersion into the water at about +20 °C for 4 h. The fabric samples after 25 and 50 frozen cycles were air-dried at room temperature for one week and then subjected to uniaxial tensile tests. The same tests have been performed on a reference group of specimens, which were not exposed to temperature change. The authors determined the tensile strength, and longitudinal stiffnesses resulting from performed tests. Although the investigated coated woven fabrics expressed a reduction in the tensile strength in water soaking conditions, the performed frozen cycles don't show a significant decrease in strength under uniaxial tensile tests.

  • Influence of dispersed phase content on the mechanical properties of electroless nanocomposite Ni-P/Si3N4 and hybrid Ni-P/Si3N4/graphite layers deposited on the AW-7075 alloy.
    • Kazimierz Czapczyk
    • Paweł Zawadzki
    • Natalia Wierzbicka
    2023 Full text Materials

    The article presents the results of mechanical testing of Ni-P/Si3N4 nanocomposite and hybrid Ni-P/Si3N4/graphite coatings deposited on AW-7075 aluminum alloy using the chemical reduction method. In terms of mechanical testing, microhardness was measured, and surface roughness and adhesion of the coatings to the aluminum substrate were determined using the “scratch test” method. The surface morphology of the deposited layers was also analyzed using light microscopy and scanning electron microscopy. Samples made of AW-7075 aluminum alloy with electroless deposited Ni-P/Si3N4 nanocomposite, Ni-P/graphite composite and hybrid Ni-P/Si3N4/graphite coatings with different content of dispersed phases were tested, and also, for comparison purposes,the Ni-P layer that constituted the matrix of the tested materials. Reinforcing phases in the form of silicon nitride nanoparticles and graphite particles were used in the layers. The purpose of the research was a thorough characterization of the coating materials used on aluminum alloys in terms of mechanical properties. Graphite is considered in this paper as it enables the reduction of the coefficient of friction through its lubricating properties. Unfortunately, graphite is difficult to use in selected layers as the only dispersion phase, because it has much lower hardness than the Ni-P coating. For this reason, a layer with a single dispersion phase in the form of graphite will be characterized by worse mechanical properties. It is necessary to add particles or nanoparticles with hardness higher than the base Ni-P coating, e.g., Si3N4, which improve the mechanical properties of the coating. The presented analyses of the results of the conducted research complement the previous studies on selected properties of nanocomposite layers with an amorphous structure and supplement the knowledge regarding their suitability for application to aluminum machine parts.

  • Influence of finishing colour on the efficiency of automated production line for wooden doors
    • Zdzisław Kwidziński
    • Marek Chodnicki
    • Łukasz Sankiewicz
    • Bartłomiej Knitowski
    • Tomasz Rogoziński
    2023

    Porta KMI Poland S.A. company has implemented a fully automated intelligent technological line TechnoPORTA for customized mass-production of technical door leaves. Each door leaf is provided with a unique QR code. It allows the line modules to individually adjust the machining parameters to the currently processed element according to the IT controlling system. Before en-tering the TechnoPorta line, the door leaves are not sorted, although the high capacity characteristic of mass production is required. Therefore, the aim of this short test was to verify the influence of leaf segregation by colour on the effi-ciency of the TechnoPorta line. Three groups of door leaves – white, black an-thracite and mixed – were tested. The test included measurements of the time interval between successive door leaves, which is the tact of the line. The test showed that each time the machining parameters are changed due to colour changes, the tact of the line is approximately twice as long. The colour segrega-tion of door leaves influences the efficiency of the production line. In the case of a single-color set, the tact of the line is half that of a mixed set. The less fre-quent the colour changes, the greater the production time savings.

  • Influence of friction stir welding technological parameters on the properties of the joints of selected aluminum alloys
    • Aleksandra Laska
    2023 Full text

    The purpose of this dissertation was to determine the effect of friction stir welding technological parameters on the properties of selected aluminum alloy joints, with consideration of the residual stresses and dislocation density in the joints. The goal of the present work was also to produce defect-free joints with high mechanical and electrochemical properties. In the dissertation, similar welds of AA6082 alloy and dissimilar welds of AA6082/AA6060 and AA5083/AA6060 alloys were produced. The parameters analyzed included tool geometry, tool traverse speed, tool rotational speed, and tool tilt angle. After visual inspection, the produced welds were studied for microstructure, tensile strength, hardness, and electrochemical resistance. In addition, the object of the study was to analyze the influence of residual stresses and the density and mobility of dislocations on the properties of the welds. The thesis concluded that the technological parameters of the process had a considerable effect on the residual stresses in the welds and the nature of the dislocations, which consequently affected the resulting mechanical and electrochemical properties of the joints.

  • Influence of geometrical and operational parameters on tooth wear in the working mechanism of a satellite motor
    • Paweł Śliwiński
    2023 Full text Scientific Reports

    This article describes the phenomena affecting the wear of the rotor of the working mechanism in a hydraulic satellite motor. The basic geometrical relationships that allow the calculation of the coordinates of the points of contact between the satellite and the rotor and the curvature are presented. A method for calculating the number of contacts of the satellite teeth with the rotor teeth and of the satellite teeth with the curvature teeth during one revolution of the rotor is proposed. A method of calculating the forces acting at the points of contact of the satellite with the rotor and the curvature is also proposed, as well as a method of calculating the stress in the tooth contact of the interacting components of the mechanism. The results of calculations of forces and stresses in tooth contact in a satellite mechanism consisting of a four-hump rotor and a six-hump curvature are presented. It is shown that the two chambers around the satellite are in the same phase in a certain range of the rotation angle of the rotor, i.e. in the emptying phase or in the filling phase. This results in the value of the force acting on the satellite resulting from the pressure difference being zero. It has also been shown that the most important parameters affecting tooth wear are the pressure difference in the working chambers of the satellite mechanism and the rotor speed.

  • Influence of Honing Parameters on the Quality of the Machined Parts and Innovations in Honing Processes
    • Piotr Sender
    • Irene Buj - Corral
    2023 Full text Metals

    The article presents a literature review dealing with the effect of the honing parameters on the quality of the machined parts, as well as with the recent innovations in honing processes. First, an overview about the honing and the plateau-honing processes is presented, considering the main parameters that can be varied during machining. Then, the influence of the honing parameters on surface finish, shape deviation and material removal rate is presented. Finally, some special and innovative applications of the honing process are described. For example, honing with variable kinematics allows obtaining oil grooves that are not rectilinear but curvilinear, in order to reduce the temperature of the part during machining and thus obtaining better surface finish and lower shape deviation. Automation of the honing machines is useful to improve both the production and the verification process. Another innovation consists of using 3D printed tools in honing processes, which will help to obtain abrasive tools with complex shapes, for example by means of powder bed fusion processes.

  • Influence of hydrochloric acid concentration and type of nitrogen source on the electrochemical performance of TiO2/N-MoS2 for energy storage applications
    • Zuzanna Zarach
    • Andrzej Nowak
    • Konrad Trzciński
    • Grzegorz Gajowiec
    • Grzegorz Trykowski
    • Sawczak Mirosław
    • Marcin Łapiński
    • Mariusz Szkoda
    2023 Full text APPLIED SURFACE SCIENCE

    In this work, nitrogen-doped molybdenum sulfide was directly deposited on titanium dioxide nanotubes substrate (TiO2/N-MoS2) during hydrothermal synthesis. The study focuses on the influence of hydrochloric acid concentration used for the synthesis, with the results indicating its essential role in thioacetamide hydrolysis and thus in the effectiveness of the N-MoS2 deposition. The electrode material itself is characterized by an initial capacitance of 320 mF cm−2 with 76 % capacitance retention after 10 000 cycles. Moreover, the effect of nitrogen source on the physical and capacitive properties is investigated, revealing that the simultaneous addition of aniline and ammonium persulfate contributes to the improvement of crystallinity and overall electrochemical performance of the electrode material. The analysis of charge storage mechanisms also indicates that the introduction of nitrogen atoms significantly affects the contribution of diffusion-controlled processes. In the construction of a symmetrical device, the specific capacitance of 76 F g−1 and areal capacitance of 70 mF cm−2 with the superior coulombic efficiency and 84 % of capacitance retention after 15,000 cycles is observed, with 11.1 W kg−1 and 5193.4 Wh kg−1 of energy and power density of the device, respectively.

  • Influence of hydrogen on a nanocrystalline high-entropy oxide with application potential in hydrogen technologies
    • Kamil Domaradzki
    • Marek Nowak
    • Maciej Sitarz
    • Marcin Łapiński
    • Tomasz Brylewski
    • Mieczysław Jurczyk
    2023 CERAMICS INTERNATIONAL

    The influence of hydrogen on a (Co0⋅2Cu0⋅2Mg0⋅2Ni0⋅2Zn0.2)O HEO with a rock salt structure was studied. Two forms of this HEO (nanopowder and sinter) were prepared via mechanochemical synthesis (MS) and additional heat treatment, respectively. The chemical stability of the synthesized samples in a pure hydrogen atmosphere was investigated using Sievert’s technique. High-pressure hydrogenation at 250 ◦C had no noticeable effect on the HEO sinter. The sintered sample was chemically, structurally, and morphologically stable, as confirmed via the XRD, Raman spectroscopy, SEM, and XPS techniques. Thermogravimetric analysis (TGA) showed the sinter to be stable in an argon gas mixture with 5 vol% of hydrogen and over the temperature range of up to 400 ◦C.

  • Influence of Phosphorus Speciation on Its Chemical Removal from Reject Water from Dewatering of Municipal Sewage Sludge
    • Eliza Kulbat
    • Krzysztof Czerwionka
    2023 Full text ENERGIES

    The aim of the presented research was the assessment of phosphorus speciation impact on the precipitation of phosphorus in reject water using Ca(OH)2. To achieve this, phosphorus speciation (organic and inorganic phosphorus in suspension and in dissolved form) in reject water that is produced during sludge dewatering, after methane digestion in wastewater treatment plants (WWTPs), was determined. This study covered the materials from four WWTPs with different compositions of feedstock for anaerobic digestion (AnD). In one, the AnD process of primary and secondary sludge was carried out without co-substrate, while in three others, co-substrate (waste from the agri-food industry and external waste-activated sludge and fats from industrial plants) was examined. The investigation was conducted in batch reactors using doses of Ca(OH)2 ranging from 2500 to 5500 mg Ca/dm3. The percentage of phosphorus forms determined in the raw reject water was similar, with the dominant form being soluble reactive phosphorus (SPR) (percentage from 87 to 96%). The small differences observed were dependent on the composition of the AnD feedstock. The results showed that, in all analysed wastewater, very high (exceeding 99.9%) phosphate phosphorus removal efficiencies were obtained using Ca(OH)2 for short reaction times (t = 1 h). The efficiency of phosphate removal depended on pH but not on the forms of phosphorus in the analysed reject water.

  • Influence of Soft Soil Samples Quality on the Compressibility and Undrained Shear Strength – Seven Lessons Learned From the Vistula Marshlands
    • Jakub Konkol
    2023 Full text Studia Geotechnica et Mechanica

    This technical article presents the influence of sample quality on the compressibility parameters and undrained shear strength ( c u ) of soft soils from the Vistula Marshlands. The analysis covers: (1) quality of soft soil according to three criteria: void ratio (Δ e / e 0 index), volumetric strain (Δ ɛ v ) and C r / C c ratio; (2) influence of storage time on quality; (3) influence of sample quality on undrained shear strength ( c u ), and (4) reliability of compression and undrained shear strength parameters estimation. The sample quality of three different soft soils (peat, organic clays, and organic silts) was investigated using dataset of geotechnical investigations from the Vistula Marshlands. The reliability of oedometer tests and compressibility parameters determination was shown. Different undrained shear strength estimates (from lab and field tests) were juxtaposed with sample quality. In situ estimates of undrained shear strength were compared with results of triaxial tests and direct simple shear test on reconstituted samples as well as SHANSEP estimates. The results of research are grouped in seven lessons. The most important outcomes are: (1) the quality of samples is at best moderate or poor and there is no significant influence of storage time on sample quality, (2) regardless of testing method, the undrained shear strength natural variability of the Vistula Marshlands soft soils is between 20% and 50% depending on deposit depth and soil type, (3) the most accurate estimation of undrained shear strength can be obtained from field vane test (FVT) while unconsolidated, undrained compression (UUC) triaxial tests should be avoided, (4) SHANSEP approach can be considered as a valuable estimate of c u (next to the FVTs), which additionally allows in relatively easy way to establish lower and upper bounds of c u .

  • Influence of soil anisotropic stiffness on the deformation induced by an open pit excavation.
    • Katarzyna Lisewska
    • Marcin Cudny
    2023 Full text Archives of Civil Engineering

    In this paper, the problem of deformation induced by an open pit excavation in anisotropic stiff soils is analysed by FE modelling. The presented research is focused on the influence of material model with anisotropic stiffness on the accuracy of deformation predictions as compared with the field measurements. A new hyperelastic-plastic model is applied to simulate anisotropic mechanical behaviour of stiff soils. It is capable to reproduce mixed variable stress-induced anisotropy and constant inherent cross-anisotropy of the small strain stiffness. The degradation of stiffness depending on strain is modelled with the Brick-type model. The model formulation and parameters are briefly presented. General deformation pattern obtained in the exemplary 2D boundary value problem of an open pit excavation is investigated considering different values of inherent cross-anisotropy coefficient of small strain stiffness. The numerical simulations are performed as a coupled deformation-flow analysis which allows to properly model the drainage conditions. The excavation phases are simulated by removal of soil layers according to the realistic time schedule. Finally, the monitored case of the trial open pit excavation in heavily overconsolidated Oxford Clay at Elstow, UK is simulated with proposed material model both in 2D and 3D conditions. The obtained calculation results are compared with displacement measurements and discussed.

  • Influence of Surface Laser Treatment on Mechanical Properties and Residual Stresses of Titanium and its Alloys
    • Magdalena Jażdżewska
    • Beata Majkowska-Marzec
    • Roman Ostrowski
    • Jean-marc Olive
    2023 Full text Advances in Science and Technology Research Journal

    Surface modification of the titanium and its alloys used in implantology with a long-pulse laser can change the surface topography, but it also leads to changes in the stress sign and magnitude in the resulting subsurface layer. The presented research was aimed at evaluating the state of stress after laser remelting with the Nd:YAG laser of pre-etched titanium alloys Ti6Al4V and Ti13Nb13Zr and pure titanium. The obtained surface layers were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), optical profilography, and nanoindentation studies. Based on the results obtained after the nanoindentation tests, the character of the stresses generated in the melted layers was calculated and determined. Laser processing resulted in surface layer thicknesses between 191-320 µm and surface roughness Ra between 2.89-5.40 µm. Laser processing caused increasing hardness, and its highest value was observed for the titanium alloy Ti13Nb13Zr - 5.18 GPa. The tensile stresses appeared following laser treatment and increased with elevating laser power up to the highest value for titanium.

  • Influence of Surface-Modified Montmorillonite Clays on the Properties of Elastomeric Thin Layer Nanocomposites
    • Adam Olszewski
    • Aleksandra Ławniczak
    • Paulina Kosmela
    • Marcin Strąkowski
    • Aleksandra Mielewczyk-Gryń
    • Aleksander Hejna
    • Łukasz Piszczyk
    2023 Full text Materials

    In recent years, polyurethane nanocomposites have attracted more attention due to the massive demand for materials with increasingly exceptional mechanical, optical, electrical, and thermal properties. As nanofillers have a high surface area, the interaction between the nanofiller and the polymer matrix is an essential issue for these materials. The main aim of this study is to validate the impact of the montmorillonite nanofiller (MMT) surface structure on the properties of polyurethane thin-film nanocomposites. Despite the interest in polyurethane–montmorillonite clay nanocomposites, only a few studies have explored the impact of montmorillonite surface modification on polyurethane’s material properties. For this reason, four types of polyurethane nanocomposites with up to 3% content of MMT were manufactured using the prepolymer method. The impact of montmorillonites on nanocomposites properties was tested by thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), contact angle measurement, X-ray diffraction (XRD), and optical coherence tomography (OCT). The results showed that chemical and physical interactions between the polymer matrix and functional groups on the montmorillonite surface have a considerable impact on the final properties of the materials. It was noticed that the addition of MMT changed the thermal decomposition process, increased T2% by at least 14 °C, changed the hydrophilicity of the materials, and increased the glass transition temperature. These findings have underlined the importance of montmorillonite surface structure and interactions between nanocomposite phases for the final properties of nanocomposites.

  • Influence of temperature and anion type on thermophysical properties of aqueous solutions of morpholine based amino acid ionic liquids
    • Dorota Warmińska
    • Adam Kloskowski
    2023 Full text JOURNAL OF CHEMICAL THERMODYNAMICS

    Densities and sound velocities of aqueous solutions of N-butyl-N-methylmorpholine based amino acid ionic liquids (AAILs), including N-acetyl-L-alanine, N-acetyl-Lvalinate, N-acetyl-L-leucinate, and N-acetyl-L-izoleucinate anions were measured at a temperature from 293.15 to 313.15 K at 5 K intervals and atmospheric pressure. These data were used to calculate the apparent molar volumes and the apparent molar compressibilities in the concentration range of (0.02 to 0.3) mol.kg-1. Infinite dilution values for the volumetric and acoustic properties were evaluated by an extrapolation procedure based on Redlich – Meyer type equations. The limiting apparent molar expansibility coefficients were also obtained from the slopes of the apparent molar volume at infinite dilution versus temperature. Using the Passynski method, the hydration numbers for AAILs in an aqueous medium were calculated. The results indicate that in the studied solutions, the ion-solvent interactions are determined by the hydrophobic effect, which results in the decrease of the limiting apparent molar compressibilities and an increase of limiting apparent molar expansibility coefficients in the order: [Mor1,4][N-Ac-L-Ala], [Mor1,4][N-Ac-L-Val], [Mor1,4][N-Ac-L-Leu], [Mor1,4][N-Ac-L-Izoleu]. The empirical slopes in Redlich –Rosenfeld – Meyer equations show that the hydrophobicity of amino acid anions is also responsible for the ion-ion interactions.

  • Influence of temperature and nitrogen pressure on the test without active gases for high-temperature proton exchange membrane fuel cells
    • Wojciech Rosiński
    • Andrzej Wilk
    • Christophe Turpin
    2023 Full text Archives of Electrical Engineering

    High-Temperature Proton-Exchange Membrane Fuel Cells (HT-PEMFCs) are a candidate for electrical energy supply devices in more and more applications. Most notably in the aeronautic industry. Before any use, an HT-PEMFC is preheated and after that supplied with its active gases. Only at this state, the diagnostics can be performed. A method of testing not requiring a complete start-up would be beneficial for many reasons. This article describes an extended version of the charging and discharging diagnostic method of HT-PEMFCs with no active gases. This extended approach is named “Test Without Active Gases” (TWAG). This paper presents original research on the influence of nitrogen temperature and pressure on the HT-PEMFC response to charging and discharging. A lumped-element model of an HT-PEMFC is also presented. A numerical result of using this model to recreate an experimentally obtained curve is also presented.

  • Influence of the Addition of Recycled Aggregates and Polymer Fibers on the Properties of Pervious Concrete
    • Oskar Mitrosz
    • Marzena Kurpińska
    • Mikołaj Miśkiewicz
    • Tadeusz Brzozowski
    • Hakim S. Abdelgader
    2023 Full text Materials

    The aim of the study was to check the possibility of reusing aggregate from recycled concrete waste and rubber granules from car tires as partial substitution of natural aggregate. The main objective was to investigate the effects of recycled waste aggregate modified with polymer fibers on the compressive and flexural strength, modulus of elasticity and permeability of pervious concrete. Fibers with a multifilament structure and length of 54 mm were deliberately used to strengthen the joints among grains (max size 31.5 mm). Eight batches of designed mixes were used in the production of pervious concrete at fixed water/binder ratio of 0.34 with cement content of 350 kg/m3. Results showed that the use of recycled concrete aggregate (8/31.5 mm) with replacement ratio of 50% (by weight of aggregate) improved the mechanical properties of pervious concrete in all analyzed cases. Whereas the replacement of 10% rubber waste aggregate (2/5 mm) by volume of aggregate reduced the compressive strength by a maximum of 11.4%. Addition of 2 kg/m3 of polymer fibers proved the strengthening effect of concrete structure, enhancing the compressive and tensile strengths by a maximum of 23.4% and 25.0%, respectively. The obtained test results demonstrate the possibility of using the recycled waste aggregates in decarbonization process of pervious concrete production, but further laboratory and field performance tests are needed.

  • Influence of water soaking on the ultimate tensile strength of polyester-based coated woven fabrics
    • Andrzej Ambroziak
    • Paweł Kłosowski
    2023 Full text Archives of Civil Engineering

    This research aims to determine the influence of water-soaking on polyester-based coated woven fabrics for ultimate tensile strength and elongation at break under uniaxial tensile tests. The paper begins with a short survey of literature concerning the investigation of the determination of coated woven fabric properties. The authors carried out the uniaxial tensile tests with an application of a flat grip to establish the values of the ultimate tensile strength of groups of specimens treated with different moisture conditions. SEM fractography is performed to determine the cross-section structures of coated woven fabrics. The change in the mechanical properties caused by the influence of water immersion has not been noticed in the performed investigations.

  • Influence of windsurfing fin stiffness distribution on the lift-drag characteristics
    • Hanna Pruszko
    • Maciej Reichel
    • Tomasz Mikulski
    2023 Full text

    This article addresses the problem of determining the hydromechanical loads generated by flexible hydrofoils. The research was done on the example of the composite windsurfing fin for the RS:X monotype class. Despite the assumption of fins identity, everyday practice showed that variations of mechanical properties occur and strongly affect their performance. Therefore, we decided to study the differences between the windsurfing fins' stiffness and quantify the resulting variations in performance. The study was done using mainly computational methods supported by the experimental investigation. The two-way Fluid-Structure Interaction (FSI) calculations were performed to investigate this problem. From a large population of measured fins, three fins were selected for calculations, each representing various stiffness properties – rigid, moderate and flexible. The FSI calculations were performed using Abaqus and Star-CCM+ explicit coupling. The substitute Finite Element Method (FEA) model was created since the composite stacking sequence was unknown. Each fin was divided into eight sections, and the material properties of each section were identified based on the experimental investigation results. The FSI calculations aimed to find lift and drag forces generated by the fins with various stiffness distributions and the quasi-static deformation of the structure. The calculations were performed for one speed and several angles of attack. Based on that, the lift and drag forces were evaluated. The calculations obtained for flexible fins were compared to a rigid hydrofoil. Significant differences between the performance of the fins were obtained, depending on the hydrofoil angle of attack.