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Politechniki Gdańskiej

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  • Special Issue on “Advanced Liquid Waste and Gas Waste Treatment Processes”
    • Piotr Rybarczyk
    2023 Pełny tekst Processes

    The editorial contains a short review of the content of the Special Issue on waste gas and liquid streams treatment strategies.

  • Spectrum Sensing Based on Hybrid Spectrum Handoff in Cognitive Radio Networks
    • Lakshminarayanan Vaduganathan
    • Shubhangi Neware
    • Przemysław Falkowski-Gilski
    • Parameshachari Bidare Divakarachari
    2023 Pełny tekst ENTROPY

    The rapid advancement of wireless communication combined with insufficient spectrum exploitation opens the door for the expansion of novel wireless services. Cognitive radio network (CRN) technology makes it possible to periodically access the open spectrum bands, which in turn improves the effectiveness of CRNs. Spectrum sensing (SS), which allows unauthorized users to locate open spectrum bands, plays a fundamental part in CRNs. A precise approximation of the power spectrum is essential to accomplish this. On the assumption that each SU’s parameter vector contains some globally and partially shared parameters, spectrum sensing is viewed as a parameter estimation issue. Distributed and cooperative spectrum sensing (CSS) is a key component of this concept. This work introduces a new component-specific cooperative spectrum sensing model (CSCSSM) in CRNs considering the amplitude and phase components of the input signal including Component Specific Adaptive Estimation (CSAE) for mean squared deviation (MSD) formulation. The proposed concept ensures minimum information loss compared to the traditional methods that consider error calculation among the direct signal vectors. The experimental results and performance analysis prove the robustness and efficiency of the proposed work over the traditional methods.

  • Speed estimation of a car at impact with a W-beam guardrail using numerical simulations and machine learning
    • Dawid Bruski
    • Łukasz Pachocki
    • Adam Ścięgaj
    • Wojciech Witkowski
    2023 Pełny tekst ADVANCES IN ENGINEERING SOFTWARE

    This paper aimed at developing a new method of estimating the impact speed of a passenger car at the moment of a crash into a W-beam road safety barrier. The determination of such a speed based on the accident outcomes is demanding, because often there is no access to full accident data. However, accurate determination of the impact speed is one of the key elements in the reconstruction of road accidents. A machine learning algorithm was used to create the speed estimation model. The model was based on regression trees algorithms, with base regressors forming a final voting ensemble. The model was trained, validated, and tested using a database containing results from full-scale crash tests and numerical simulations. The developed machine learning model had a mean absolute error of 6.76 km/h with a standard deviation of 1.01 km/h on the cross-validation set, and a coefficient of determination, R2, of 0.85. This model was used to estimate the impact speed of the vehicle in three real road accidents with the W-beam barrier, and then the determined speeds were used in additional simulations to verify the results. A good quantitative and qualitative agreement between the simulation and accident outcomes was achieved, and this confirmed that the proposed method and the developed ML models combined with numerical simulations and full-scale crash tests can be effective tools for estimating the speed of the vehicle at impact with a roadside barrier.

  • Spike patterns and chaos in a map-based neuron model
    • Piotr Bartłomiejczyk
    • Frank Llovera Trujillo
    • Justyna Signerska-Rynkowska
    2023 Pełny tekst International Journal of Applied Mathematics and Computer Science

    The work studies the well-known map-based model of neuronal dynamics introduced in 2007 by Courbage, Nekorkin and Vdovin, important due to various medical applications. We also review and extend some of the existing results concerning β-transformations and (expanding) Lorenz mappings. Then we apply them for deducing important properties of spike-trains generated by the CNV model and explain their implications for neuron behaviour. In particular, using recent theorems of rotation theory for Lorenz-like maps, we provide a classification of periodic spiking patterns in this model.

  • Spin-Resolved Band Structure of Hoffman Clathrate [Fe(pz)2Pt(CN)4] as an Essential Tool to Predict Optical Spectra of Metal–Organic Frameworks
    • Adrian Olejnik
    • Wioletta Kopeć
    • Dominik Maskowicz
    • Mirosław Sawczak
    2023 ACS Applied Materials & Interfaces

    Paramount spin-crossover properties of the 3D-Hoffman metalorganic framework (MOF) [Fe(pz)2Pt(CN)4] are generally described on the basis of the ligand field theory, which provides adequate insight into theoretical and simulation analysis of spintronic complexes. However, the ligand field approximation does not take into account the 3D periodicity of the actual complex lattice and surface effects and therefore cannot predict a full-scale periodic structure without utilizing more advanced methods. Therefore, in this paper, the electronic properties of the exemplar MOF were analyzed from the band structure perspective in low-spin (LS) and high-spin (HS) states. The density-of-states spectra determined for both spin-up and spin-down electrons of Fe d6 orbitals indicate spin–orbital splitting and delocalization for HS due to spin polarization in the iron atom ligand field. Presence of the surface states in the real crystal causes a red shift of the metal–metal charge transfer (MMCT) and metal–ligand charge transfer (MLCT) peaks for both HS and LS states. The addition of residual water molecules and disorder among the pyrazine rings reveal additional influences on the positions of the pyrazine band and, therefore, on the absorption spectra of the crystal. The results show a magnification of the peak correlated with the MLCT in the HS state and a significant red shift of the LS characteristic absorption band. The presented approach involving band structure analysis delivers a more complete image of the electronic properties of the [Fe(pz)2Pt(CN)4] crystalline network and can be a landmark for insightful studies of other MOFs

  • Splice variants of mitofusin 2 shape the endoplasmic reticulum and tether it to mitochondria
    • Déborah Naón
    • María Isabel Hernández-Alvarez
    • Satoko Shinjo
    • Miłosz Wieczór
    • Saska Ivanova
    • Olga Martins de Brito
    • Albert Quintana
    • Juan Hidalgo
    • Manuel Palacín
    • Pilar Aparicio
    • Juan Castellanos
    • Luis Lores
    • David Sebastián
    • Sonia Fernández-Veledo
    • Joan Vendrell
    • Jorge Joven
    • Modesto Orozco
    • Antonio Zorzano
    • Luca Scorrano
    2023 SCIENCE

    In eukaryotic cells, different organelles interact at membrane contact sites stabilized by tethers. Mitochondrial mitofusin 2 (MFN2) acts as a membrane tether that interacts with an unknown partner on the endoplasmic reticulum (ER). In this work, we identified the MFN2 splice variant ERMIT2 as the ER tethering partner of MFN2. Splicing of MFN2 produced ERMIT2 and ERMIN2, two ER-specific variants. ERMIN2 regulated ER morphology, whereas ERMIT2 localized at the ER-mitochondria interface and interacted with mitochondrial mitofusins to tether ER and mitochondria. This tethering allowed efficient mitochondrial calcium ion uptake and phospholipid transfer. Expression of ERMIT2 ameliorated the ER stress, inflammation, and fibrosis typical of liver-specific Mfn2 knockout mice. Thus, ER-specific MFN2 variants display entirely extramitochondrial MFN2 functions involved in interorganellar tethering and liver metabolic activities.

  • Społeczny wymiar adaptacji do zmian klimatu w środowisku miejskim na przykładzie Gdańska
    • Małgorzata Dymnicka
    • Paweł Starosta
    • Jarosław Załęcki
    2023 Pełny tekst PRZEGLĄD SOCJOLOGICZNY

    Kwestie zmian klimatycznych przestały być przedmiotem zainteresowania jedynie wąskich grup specjalistów, a stały się problemem społecznym angażującym szerszą opinię publiczną. Wobec wzrastającego znaczenia problemów środowiskowych w społeczeństwach, głównie na przełomie XX i XXI wieku, władze centralne we współpracy z samorządami miejskimi zaczęły podejmować działania na rzecz wsparcia tzw. środowiskowej (zielonej) polityki. Artykuł poświęcony jest charakterystyce stanu świadomości ekologicznej mieszkańców Gdańska. Autorzy przedstawiają wnioski ze zrealizowanych badań na temat wybranych zagadnień związanych ze zmianami klimatycznymi. W pierwszej części tekstu przywołują opracowania dotyczące kwestii klimatycznej i jej obecności w dyskursie ekologicznym, który w ostatnich dwóch dekadach angażuje coraz więcej podmiotów podejmujących działania na rzecz ochrony środowiska przyrodniczego. W drugiej części skupiają uwagę na analizie empirycznej zachowań proekologicznych i ich uwarunkowań społecznych.

  • Spray-Based Method for Protecting and Restoring Historic Adobe Walls Using Nanomontmorillonite Clay
    • Mona Khasar
    • Hamed Niroumand
    • Maryam Afsharpour
    • Lech Bałachowski
    2023 Pełny tekst ACS NANO

    Restoringandprotectinghistoricbuildingsworldwideareimportant becauseheritagebuildingsarerecordsofthecivilizationsofvariouscountries.Herein, nanotechnologywasusedtorestorehistoricadobewalls.AccordingtotheIranPatent andTrademarkOffice(IRPATENT)102665,nanomontmorilloniteclayhasbeen selectedasanaturalandcompatiblematerialwithadobe.Furthermore,ithasbeenused asnanospraytobeaminimallyinvasivemethodtofillcavitiesandcracksintheadobe surface.Variouspercentagesofnanomontmorilloniteclay(1−4%)intheethanolsolvent andthefrequencyofsprayingonthewallsurfacewereevaluated.Scanningelectron microscopyandatomicforcemicroscopyimages,porositytests,watercapillary absorption,andcompressivestrengthtestswereusedtoevaluatetheefficiencyofthe method,analyzecavityfilling,anddetecttheoptimalpercentageofnanomontmorillonite clay.Resultsindicatethatthedoubleuseofthe1%nanomontmorilloniteclaysolution exhibitedthebestresults,filledthecavities,andreducedtheporesonthesurfaceofthe adobe,increasingcompressivestrengthandreducingwaterabsorptionandhydraulic conductivity.Theuseofamoredilutesolutioncausesthenanomontmorilloniteclaytopenetratedeeplyintothewall.This innovativemethodcanhelpmitigatetheexistingdisadvantagesofhistoricadobewalls.

  • Stability Enhancement of Grid-Connected Wind Power Generation System Using PSS, SFCL and STATCOM
    • Muhammad Sarwar
    • Muhammad Arshed
    • Babar Hussain
    • Muhammad Rasheed
    • Hanan Tariq
    • Stanisław Czapp
    • Sarmad Tariq
    • Intisar Ali Sajjad
    2023 Pełny tekst IEEE Access

    The stability related issues may occur in a power system due to disturbances in generating or loading conditions, especially in the presence of distributed generation (DG) based on renewable energy resources (RERs). This paper proposes a novel strategy for the stability enhancement of a wind power generation system (WPGS) by using a combination of three devices, namely, a power system stabilizer (PSS), resistive superconductor fault current limiter (R-SFCL) and static synchronous compensator (STATCOM). The small signal (SS) stability of the test system is enhanced by selecting the best PSS type from the different types of PSS. An R-SFCL is used for improving the rotor angle and the frequency stability of the test system. Two indices, namely, transient stability index and sum of maximum deviations (SMD) index are introduced for determining the optimal locations of different sized R-SFCLs for increasing the rotor angle stability. The sensitivity index (SI) based on the power change between areas is applied for determining the optimal locations of different sized R-SFCLs for enhancing the frequency stability. Along with rotor angle and frequency stability, LVRT capability improvement of the wind farm using STATCOM is also considered. Finally, the combined effect of R-SFCL and STATCOM on the rotor angle and the frequency stability, for different fault locations, is also investigated for determining the optimal location of an R-SFCL in the presence of STATCOM. The results presented in the paper show that STATCOM affects both the number of feasible locations and the optimal locations that can be selected for different sized R-SFCLs for augmenting the rotor angle and the frequency stability of the system during faults. Moreover, it is pointed out that an optimal combination between the different sizes and the locations of R-SFCLs and STATCOM exists to enhance the overall stability of the test system under fault conditions.

  • Stability Investigation of the PCM Nanocomposites
    • Janusz Cieśliński
    • Paulina Boroń
    • Maciej Fabrykiewicz
    2023 Pełny tekst Acta Mechanica et Automatica

    Ensuring the stability is a key issue to be solved for the technical application of nanocomposites. In this work, fatty acid P1801 served as base phase change material (PCM)P1801, and its main ingredients are palmitic acid (58%) and stearic acid (38%). Titania (TiO2) and alumina (Al2O3) with mass concentrations of 1% and 5% were selected as nanoparticles, while polyvinylpyrrolidone (PVP) or oleic acid (OA) with mass concentrations of 5% were tested as surfactants. On the basis of the measured temperature distributions in the sample, which is subject to melting and solidification processes, it was determined which of the tested nanocomposites are stable and which are not. In addition, a thermal test was proposed to assess the stability of the produced nanoPCM, which consists in measuring the temperature distribution versus time according to a precisely given procedure.

  • State Interventionism in Tax System - Example of Action in a COVID-19 Crisis
    • Piotr Kasprzak
    2023 Pełny tekst International Journal of Social Science

    The following article presents and classifies changes in tax systems of selected countries as well as counts them as the response to the emergence of the crisis caused by the COVID-19 pandemic. Such actions were undertaken the context of state interventionism in the tax system. In order to achieve the objective of presenting the state interventionism in the context of tax rates, an analysis of the literature on the phenomenon described, as well as specialised industry reports, were analysed. Among the research methods used are literature studies as well as review and an analysis of reports published by the OECD that dealt with the subject described and analysed in the paper. The article focuses on the presentation of the change in the individual tax burden in the countries selected for analysis. It also focuses on the presentation of tax interventionism as an opportunity for the state to influence the economy against the negative effects of the crisis. It should be noted that crises and crisis situations play an crucial role in the economic life of a country, but their course and ultimate consequences depend on the measures taken by individual countries to reduce the negative effects of their outbreak. The COVID-19 pandemic had a significant impact on changing the macroeconomic perspective and situation of many countries around the globe. The pandemic outbreak had also a negative impact on the functioning of companies (especially SME sector). As a result, governments have decided to introduce various relief measures, including changes in the functioning of tax systems. This should be considered as the state interventionism.

  • Static in vitro digestion model adapted to the general older adult population: an INFOGEST international consensus
    • O Ménard
    • U Lesmes
    • C. S. Shani-Levi
    • A. Araiza Calahorra
    • A. Lavoisier
    • M. Morzel
    • A. Rieder
    • G. Feron
    • S. Nebbia
    • L. Mashiah
    • Ana Andres
    • G. Bornhorst
    • F Carriere
    • L Egger
    • S. Gwala
    • Ana Heredia
    • B Kirkhus
    • Adam Macierzanka
    • R Portmann
    • I Recio
    • V. Santé-Lhoutellier
    • C. Tournier
    • A. Sarkar
    • A Brodkorb
    • Alan Mackie
    • D Dupont
    2023 Pełny tekst Food & Function

    Understanding the mechanisms of food digestion is of paramount importance to determine the effect foods have on human health. Significant knowledge on the fate of food during digestion has been generated in healthy adults due to the development of physiologically-relevant in vitro digestion models. However, it appears that the performance of the oro-gastrointestinal tract is affected by ageing and that a model simulating the digestive conditions found in a younger adult (<65 years) is not relevant for an older adult (>65 years). The objectives of the present paper were: (1) to conduct an exhaustive literature search to find data on the physiological parameters of the older adult oro-gastrointestinal tract, (2) to define the parameters of an in vitro digestion model adapted to the older adult. International experts have discussed all the parameters during a dedicated workshop organized within the INFOGEST network. Data on food bolus properties collected in the older adult were gathered, including food particle size found in older adult boluses. In the stomach and small intestine, data suggest that significant physiological changes are observed between younger and older adults. In the latter, the rate of gastric emptying is slowed down, the pH of the stomach content is higher, the amount of secretions and thus the hydrolytic activities of gastric and intestinal digestive enzymes are reduced and the concentration of bile salts lower. The consensus in vitro digestion model of the older adult proposed here will allow significant progress to be made in understanding the fate of food in this specific population, facilitating the development of foods adapted to their nutritional needs. Nevertheless, better foundational data when available and further refinement of the parameters will be needed to implement the proposed model in the future.

  • Static Shape and Stress Control of Trusses with Optimum Time, Actuators and Actuation
    • Najmadeen Saeed
    • Ahmed Manguri
    • Marcin Szczepański
    • Robert Jankowski
    • Barham. A. Haydar
    2023 Pełny tekst International Journal of Civil Engineering

    Traditional shape and stress control of structures use many actuators and require enormous time to find reasonable solutions that need designers to input specific target displacement and stress. This study employs a linear technique to static shape and stress control of pin-jointed assemblies as a theoretical advancement to prior works and provides a comparative analysis against previously established works. The study evaluates the proposed method using MATLAB to find the optimum set of actuators, and MATLAB and SAP2000 to verify the actuation results obtained through applying the set of actuations to the numericalmodels. The proposed method minimizes the number of trials, count of actuators, and total actuation up to 83%, 73%, and 50%, respectively. Furthermore, the optimum solution could be found in a single trial. The study focuses on the three aspects: (a) finding the optimal count of actuators; (b) optimum amount of actuation using fmincon function; and c) Implementing two-sided inequalities to control equations allowing designers to develop target internal forces and nodal displacements, as domains rather than specific numbers. This improves the optimization process affecting actuator count, total actuation elements, and processing time.

  • Statistical evaluation of the changes in cellulose properties caused by the stepwise solvent exchange and esterification
    • Stefan Cichosz
    • Katarzyna Dems-Rudnicka
    • Marcin Łapiński
    • Aleksandra Jastrzębska
    • Anna Masek
    2023 INDUSTRIAL CROPS AND PRODUCTS

    The objective of the research was to empirically confirm the changes in cellulose reactivity caused by the pre-treatment with solvents of different polarity. Therefore, 5 solvents varying in their polar component of surface tension from 0 to 4.6 mN/m were chosen. Their impact on the biopolymer properties was carefully analysed concerning chemical structure, crystallinity and surface characteristics. It was revealed that the length of 6OH⋯O3′ intermolecular H-bonds increased upon each solvent-exchange from (0.2748 ± 0.0001) nm to approx. 0.2760 nm for non-polar solvents, hence, potentially affecting cellulose structure and availability of active centres capable of reaction. As a consequence of structural variations, dioxane- and toluene-exchanged cellulose exhibited, respectively, the lowest (around 0.6 mJ/m2) and the highest (approx. 3.1 mJ/m2) polar component of surface free energy. Therefore, these samples were esterified. Further investigation successfully confirmed expected differences. Toluene-exchanged sample exhibited degree of substitution oscillating around 20%, while dioxane-exchanged specimen – approx. 7%.

  • Steady-State Vibration Level Measurement of the Five-Phase Induction Machine during Third Harmonic Injection or Open-Phase Faults
    • Adam Muc
    • Marcin Morawiec
    • Filip Wilczyński
    2023 ENERGIES

    Multiphase electric machines are increasingly used in various industries and for electromobility. Complex systems have been developed for the control and powering of multiphase machines, which require verification. The quality of control and the power supply of electric machines is usually evaluated by analyzing various electrical parameters. On the other hand, taking into account the fact that a motor is an electrical-mechanical object, its full diagnostics should also include the analysis of vibration signals to verify the operation of the motor as a mechanical device. In this paper, a sensorless control algorithm was studied and applied to a 5-phase induction motor. Various scenarios were considered; in particular, the operation of the studied motor in the absence of one or two phases and in the case of the introduction of the third harmonic to increase the torque was analyzed. In the scenarios considered, the motor was connected to another machine and operated with no load as well as with a preset load. The results obtained were analyzed in the time and frequency domain and were related to the standards used.

  • Stenty naczyniowe – problematyka i biomateriały
    • Klaudia Malisz
    • Marcin Hellmann
    • Beata Świeczko-Żurek
    2023

    Angioplastyka z opcjonalną implantacją stentu odgrywa ważną rolę w leczeniu chorób układu sercowo-naczyniowego w przebiegu miażdżycy. Obecnie na rynku można znaleźć implanty naczyniowe z różnych materiałów, pomimo tego nadal prowadzone są badania nad nowymi technologiami zapewniającymi lepsze własności mechaniczne, fizykochemiczne i biologiczne powłokom, a także usprawniającymi sposoby uwalniania leków. Stenty uwalniające leki dostarczają środki antyproliferacyjne, co znacznie obniża częstość nawrotów zwężenia w porównaniu ze stentami z czystego metalu. Chociaż w pełni biodegradowalne rusztowania potencjalnie mają zapobiegać późnym powikłaniom, nie osiągnęły jeszcze wyników równoważnych z wynikami konwencjonalnych metalowych stentów uwalniających leki we wczesnych latach po implantacji. Innym rozwiązaniem jest zastosowanie powłok, które nadają wyjątkowych właściwości materiałowi, np. wykorzystując powłoki diamentopodobne lub domieszkując powłokę nanocząstkami. Celem niniejszego artykułu jest przedstawienie najnowszych materiałów do stosowania w kardiologii i angiologii interwencyjnej jako stenty naczyniowe.

  • Sterowanie predykcyjne i fuzja danych w systemie dynamicznego pozycjonowania statku
    • Krzysztof Jaroś
    2023 Pełny tekst

    Rozprawa doktorska poświęcona jest badaniu zastosowania fuzji danych oraz sterowania predykcyjnego w systemie dynamicznego pozycjonowania statku. W pierwszej części pracy przedstawiono historię rozwoju systemów dynamicznego pozycjonowania, różne metody estymacji położenia statku, metody sterowania oraz cel i tezę pracy. Następnie zaprezentowano model matematyczny statku, kinematykę oraz dynamikę. W kolejnej części przedstawiono algorytmy fuzji danych, takie jak filtr Kalmana, rozszerzony filtr Kalmana, nieliniowy obserwator oraz filtr cząsteczkowy. W rozprawie przedstawiono również algorytm kaskadowego połączenia filtru cząsteczkowego i rozszerzonego filtru Kalmana. W kolejnej części zaprezentowano algorytmy sterowania, takie jak PID, regulator backstepping oraz sterowanie predykcyjne. W pracy przedstawiono dwa kierunki badań. Pierwszy dotyczy zadania fuzji danych z wykorzystaniem nadmiarowej struktury pomiarowej dokonującej pomiaru położenia, kursu i prędkości w celu estymacji tych wielkości i zakłóceń środowiskowych. Drugi kierunek badań dotyczy poprawy jakości sterowania statkiem z wykorzystaniem nieliniowego modelu statku w sterowaniu predykcyjnym. Wyniki tych badań wskazują, że połączenie fuzji danych i sterowania predykcyjnego pozwala na zwiększenie dokładności pozycjonowania statku oraz bezpieczeństwa statku w sytuacjach awaryjnych.

  • Stiffness of cold-recycled mixtures under variable deformation conditions in the IT-CY test
    • Mariusz Jaczewski
    • Cezary Szydłowski
    • Bohdan Dołżycki
    2023 Pełny tekst Case Studies in Construction Materials

    Stiffness modulus belongs to the most important properties describing the cold-recycled mixtures (CRM) in terms of their usability in road pavement structures. Previous research proved that this property is strongly dependent on the scheme and conditions of the test (temperature and time of loading) and the time that has passed since the compaction of the specimen or pavement layer. It is a result of the influence of two different types of bonds – hydraulic bonds from cement and bituminous bonds from bituminous emulsion or foamed bitumen. Research presented in this paper showed that the target horizontal deformation values selected during the stiffness modulus test have a strong impact on the obtained results as well. In this paper the popular Indirect Tensile Stiffness Modulus (ITSM) test on cylindrical specimen (IT-CY scheme) was used to show the dependence of the stiffness modulus values on the selected target horizontal deformation level. Research was conducted on four different CRM mixtures and three reference materials. The research proved that even for a narrow deformation range the CRMs do not present linear viscoelastic behavior and display very high effort of material even for typical test conditions. In consequence, they are very prone to failure. Research also proved that CRM mixtures present different rheological behavior than cement concrete or asphalt concrete, and more attention should be given to establishing proper test conditions. Based on the research, it was determined that the recommended target horizontal deformation in IT-CY test of CRM should be reduced to 3 μm.

  • Stochastic optimisation algorithm for optimisation of controller parameters for control of dissolved oxygen in wastewater treatment plant
    • Robert Piotrowski
    • Michał Wonia
    • Adam Wonia
    2023 Journal of Water Process Engineering

    Wastewater treatment plants (WWTPs) are very important facilities for mankind. They enable the removal and neutralisation of man-made pollutants. Therefore, it is important for wastewater treatment plants to operate as efficiently as possible so that the level of pollutants in the treated wastewater meets specific requirements. This paper concerns the design of a hierarchical nonlinear adaptive control system for dissolved oxygen (DO) concentration in wastewater for a biological Sequential Batch Reactor (SBR). The parameters of the control system used are optimised to ensure the best possible control quality and low energy consumption at the same time. Based on data collected from a case study WWTP, an Activated Sludge Model 2d (ASM2d) of the biological processes and a model of the aeration system are applied. The Coyote Optimization Algorithm (COA) is used to optimize the adaptive controller parameters. A Proportional-Integral-Derivative (PID) control system is also developed to compare the control results. The results obtained from simulation studies for both control systems are presented. As a result of optimised parameters, higher wastewater treatment efficiency and reduced electricity consumption are achieved.

  • Stock Markets’ Reactions to the Announcement of the Hosts. An Event Study in the Analysis of Large Sporting Events in the Years 1976–2032
    • Krystian Zawadzki
    • Marcin Potrykus
    2023 Pełny tekst Journal of Sports Economics

    This study attempts to estimate the impact of the announcements of hosts of large sporting events on domestic stock markets. The research problem is to establish a connection between the uniqueness of a sporting event and investors’ beliefs through stock price behavior. Using appropriate estimation windows, 13 different sporting events classified as large, including mega and major events, were tested. The obtained results show that, in principle, one day after the announcement of the host of a large sporting event, an average positive reaction of 0.22% is observed on national stock exchanges. The analyzed events were also classified as being neutral for capital markets or generating positive or negative reactions when the host country is announced to the public.

  • Strategies for Dealing With Software Product Management Challenges
    • Olga Springer
    • Jakub Miler
    • Michał Wróbel
    2023 Pełny tekst IEEE Access

    Software product management, which involves multiple processes and responsibilities and links to many activities within the organisation, increases the success rate of IT projects. However, the adoption of product management activities and the implementation of the software product manager role itself varies between companies. This research explores the topic of software product managers’ strategies for dealing with challenges in their work. The aim of the study is to identify and evaluate solutions to the main problems that affect the software product management process and to provide guidelines for dealing with them. For this purpose, a focus group method was adopted and 47 software product managers participated in 15 focus groups. This was followed by a survey to assess the comprehensibility and effectiveness of the solutions identified. The paper proposes a list of 39 solutions to the 5 most common problems in the work of product managers. Furthermore, based on the identified solutions and the results of discussions with experienced professionals during the focus groups, guidelines for these problems were also developed. These guidelines can be used by product managers as well as other roles working in the product development team to create their own strategies for overcoming software product management challenges and improving software engineering practices. Finally, the solutions and guidelines presented, when combined with a list of problems identified in previous research, will form a Software Product Management Guide – a framework currently under construction, as part of wider research, for product development teams to improve software engineering practices.

  • Strategy towards the use of ultrafiltration and reverse osmosis for industrial water recovery and reuse as part of the Green Deal Implementation
    • Jakub Drewnowski
    • Jan Marjanowski
    • Maciej Sadaj
    • Bartosz Szeląg
    • Joanna Szulżyk-Cieplak
    • Grzegorz Łagód
    2023 Desalination and Water Treatment

    In line with the European Parliament’s Resolution of February 10th, 2021 on the new action plan for a closed economy, most of the activities undertaken in the wastewater treatment process should focus on the search for new technologies that use wastewater as a source of water and nutrients. The paper reviews the concept of water reuse in industrial installations, with special emphasis on the use of membrane technologies for this purpose. The results of authors’ own research on effectiveness of using ultrafiltration (UF) and reverse osmosis (RO) processes to recover process water from brewery wastewater, following pretreatment by the BIOPAQ®-IC process, are presented. Raw wastewater, after averaging the parameters, was digested in an anaerobic reactor, followed by deodorization and oxidation of sulfides to sulfate in an oxidation process in a pretreatment tank. The water recovered from pretreated brewery wastewater by UF and RO membrane techniques was found to be suitable for boiler feed, cooling technology and washing process without directly cleaning beer bottles. The study used a ZeeWeed capillary immersion ultrafiltration module operating under vacuum and a module equipped with a Filmtec XLE 2125 reverse osmosis membrane. The technology improved the efficiency of contaminant removal, yielding purified and high-quality water toward the implementation of the assumptions of Circular Economy and Green Deal Implementation.

  • Stress Relaxation Behaviour Modeling in Rigid Polyurethane (PU) Elastomeric Materials
    • Paweł Zielonka
    • Krzysztof Junik
    • Szymon Duda
    • Tomasz Socha
    • Krzysztof Kula
    • Arkadiusz Denisiewicz
    • Olaleye Kayode
    • Wojciech Macek
    • Grzegorz Lesiuk
    • Wojciech Błażejewski
    2023 Pełny tekst Materials

    Polyurethane (PU) has been used in a variety of industries during the past few years due to its exceptional qualities, including strong mechanical strength, good abrasion resistance, toughness, low-temperature flexibility, etc. More specifically, PU is easily “tailored” to satisfy particular requirements. There is a lot of potential for its use in broader applications due to this structure–property link. Ordinary polyurethane items cannot satisfy people’s increased demands for comfort, quality, and novelty as living standards rise. The development of functional polyurethane has recently received tremendous commercial and academic attention as a result. In this study, the rheological behavior of a polyurethane elastomer of the PUR (rigid polyurethane) type was examined. The study’s specific goal was to examine stress relaxation for various bands of specified strains. We also suggested the use of a modified Kelvin–Voigt model to describe the stress relaxation process from the perspective of the author. For the purpose of verification, materials with two different Shore hardness ratings—80 and 90 ShA, respectively—were chosen. The outcomes made it possible to positively validate the suggested description in a variety of deformations ranging from 50% to 100%.

  • Structural and electronic properties of diamond-composed heterostructures
    • Michał Rycewicz
    2023 Pełny tekst

    Diamond is a promising material for 21st century electronics due to its high thermal and electronic conductivity, biocompatibility, chemical stability, high wear resistance, and possibility of doping. However, the semiconductor properties of diamond, especially free-standing films, have not been fully explored. Nor have their integration with polymers and fragile materials and their applications as electronic components. In this thesis, the objective was the fabrication of heterostructures containing diamond films on flexible surfaces for application in electronic devices using the change of electrical parameters under the influence of external factors. To overcome this scientific challenge, boron-doped diamonds were grown using chemical vapour deposition on tantalum. After their delamination, the resulting free-standing films were investigated and analysed using Raman spectroscopy, Scanning and Atomic Force Microscopy, Nanoindentation Tests, Electrochemical measurements, and Electrical Evaluation as a function of temperature. Next, the diamond films were utilised for fabricating six heterostructures. Based on the conducted research, these heterostructures can be used as durable, transparent electrodes, strain sensors, Schottky or Ohmic junctions, capacitors, trinitrotoluene sensors, and as a protective layer for transistors.

  • Structural and luminescence properties of B2O3-Bi2O3-AlF3 glass doped with Eu3+, Tb3+ and Tm3+ ions
    • Karolina Milewska
    • Michał Maciejewski
    • Marcin Łapiński
    • Anna Synak
    • Mirosław Behrendt
    • Wojciech Sadowski
    • Barbara Kościelska
    2023 JOURNAL OF NON-CRYSTALLINE SOLIDS

    The B2O3-Bi2O3-AlF3 glass system doped with Eu3+, Tb3+, Tm3+ and triply doped with Eu3+/Tm3+/Tb3+ ions in different molar ratios were successfully synthesized. Glass transition and crystallization temperatures were examined by Differential Scanning Calorimetry (DSC) measurements. X-ray Diffraction (XRD) confirmed the amorphous character of the samples. Fourier Transform Infrared Spectroscopy (FTIR) revealed that the glass matrix consists of [BO3] and [BO4] structural units, while X-ray Photoelectron Spectroscopy (XPS) confirmed the presence of AlF3. An increase in luminescence spectra intensity was detected by Photoluminescence Spectroscopy (Pl), due to the presence of 10 mol% of AlF3. The RE3+ ions embedded in the glass matrix can be simultaneously excited by a single UV light. According to the CIE results the emitted color can be tunable by varying the excitation wavelength and sample composition. The presented results confirm that the proposed glass system could be a candidate for color-tunable phosphors in LEDs.

  • Structural insights, biocatalytic characteristics, and application prospects of lignin-modifying enzymes for sustainable biotechnology
    • Anil Kumar Singh
    • Hafiz M N Iqbal
    • Nunzio Cardullo
    • Vera Muccilli
    • Jesús Fernández-Lucas
    • Jens Ejbye Schmidt
    • Teofil Jesionowski
    • Muhammad Bilal
    2023 Pełny tekst INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES

    Lignin modifying enzymes (LMEs) have gained widespread recognition in depolymerization of lignin polymers by oxidative cleavage. LMEs are a robust class of biocatalysts that include lignin peroxidase (LiP), manganese peroxidase (MnP), versatile peroxidase (VP), laccase (LAC), and dye-decolorizing peroxidase (DyP). Members of the LMEs family act on phenolic, non-phenolic substrates and have been widely researched for valorization of lignin, oxidative cleavage of xenobiotics and phenolics. LMEs implementation in the biotechnological and industrial sectors has sparked significant attention, although its potential future applications remain underexploited. To understand the mechanism of LMEs in sustainable pollution mitigation, several studies have been undertaken to assess the feasibility of LMEs in correlating to diverse pollutants for binding and intermolecular interactions at the molecular level. However, further investigation is required to fully comprehend the underlying mechanism. In this review we presented the key structural and functional features of LMEs, including the computational aspects, as well as the advanced applications in biotechnology and industrial research. Furthermore, concluding remarks and a look ahead, the use of LMEs coupled with computational framework, built upon artificial intelligence (AI) and machine learning (ML), has been emphasized as a recent milestone in environmental research.

  • Structural, optical and electrochemical performance of black phosphorus and black arsenic-phosphorus nanostructures
    • Łukasz Macewicz
    2023 Pełny tekst

    Black phosphorus (BP)-based nanostructures have drawn a lot of attention due to their tunable bandgap and extraordinary properties such as: high surface-to-volume ratio, large number of active sites, and prominent edges. However, low dimensional structures of black phosphorus oxidize easily, which hamper their application on a broader scale. One way to overcome these difficulties is to modify the black phosphorus structure by substituting some of the phosphorus atoms for arsenic atoms, forming black arsenic-phosphorus (b-AsP). Despite the broad variety of atomically thin, two-dimensional materials, those with a bandgap range between 0.3 and 1.5 eV are plainly missing. Black phosphorus and black arsenic-phosphorus nanostructures not only correspond to the visible and infrared spectral range, but also possess additional tuning capabilities, which can further influence their electronic properties. In this dissertation, the structural and optical properties of BP and b-AsP nanoflakes and nanoribbons have been investigated. Moreover, surface modification of electrode materials with BP and b-AsP to enhance their electrochemical performance and sensing possibilities was investigated. The electrode materials chosen for BP and b-AsP modification were titania nanotubes (TiO2NTs), commercially available gold array electrodes, and CVD-fabricated polycrystalline boron-doped diamond (BDD) films.

  • Structural, physicochemical and anticancer study of Zn complexes with pyridyl-based thiazolyl-hydrazones
    • Jovana B. Araškov
    • Natalia Maciejewska
    • Mateusz Olszewski
    • Aleksandar Višnjevac
    • Vladimir Blagojević
    • Henrique S. Fernandes
    • Sérgio F. Sousa
    • Adrián Puerta
    • José M. Padrón
    • Berta Barta Holló
    • Miguel Monge
    • María Rodríguez-castillo
    • José M. López-de-luzuriaga
    • Özlem Uğuz
    • Atıf Koca
    • Tamara R. Todorović
    • Nenad R. Filipovići
    2023 JOURNAL OF MOLECULAR STRUCTURE

    Thiazolyl-hydrazones (THs) exhibit a wide spectrum of biological activity that can be enhanced by complexation with various metal ions. Zn(II) complexes with α-pyridine-1,3-TH ligands may represent an alternative to the standard platinum-based chemotherapeutics. In addition, they show photoluminescence properties and thus can be regarded as multifunctional materials. In this study, we synthesized and characterized three neutral Zn(II) complexes (1–3) with pyridine-based TH ligands HLS1‒3 in order to investigate the influence of the ligands charge on the structure and intermolecular interactions in the solid state, and consequently photophysical properties. The deprotonation of the ligands mainly affects the relative energies of electronic levels in the complexes, compared to cationic counterparts, resulting in similar photoluminescence mechanisms and quantum yields with a small shift in emission energy. The influence of the substitution at the ligands’ periphery on the selected quantum molecular descriptors of the complexes is localized to the substitution site. Also, the substituents did not considerably influence the redox responses of the complexes. However, predominant spectral changes were observed in the course of the first reduction and oxidation processes which caused distinct spectral colour changes indicating their possible functionality for electrochromic applications. In addition, complex 1 showed antiproliferative activity with GI50 values below 2 µM on all tested cancer cell lines.

  • Structurally well-defined functionalized polyolefins and graft copolymers thereof as bitumen modifiers
    • Mateusz Malus
    • Joanna Bojda
    • Maciej Sienkiewicz
    • Miloud Bouyahyi
    • Lanti Yang
    • Javier Francisco Navarro
    • Maria Soliman
    • Rob Duchateau
    • Lidia Jasińska-Walc
    2023 CONSTRUCTION AND BUILDING MATERIALS

    Here we demonstrate the application of hydroxyl-functionalized propylene-based copolymers, poly(propylene-co-1-hexene-co-10-undecen-1-ol) (FPP) and poly(styrene-co-maleic anhydride) (SMA) graft copolymers derived thereof, poly(propylene-co-1- hexene-graft-styrene-co-maleic anhydride) (FPP-g-SMA) as bitumen modifiers. The FPP samples were synthesized via solution copolymerization, while FPP-g-SMA products were obtained via transesterification of FPP with SMA either in solution or by a melt-grafting process. FPP-g-SMA modifiers prepared in solution, having a SMA content of around 30 wt.%, performed very well as compatibilizer for bitumen, generating a polymer-modified compositions with a uniform morphology and improved nanomechanical properties, storage stability, rheological properties and high- temperature performance as compared to neat bitumen samples.

  • Structure redetermination, transport and thermal properties of the YNi3Al9 compound
    • Ihor Oshchapovskyy
    • Ebube E. Oyeka
    • Thao Tran
    • Tomasz Klimczuk
    • Michał Winiarski
    2023 Pełny tekst JOURNAL OF SOLID STATE CHEMISTRY

    Single crystals of completely ordered variant of the YNi3Al9 compound were grown by self-flux method with excess of aluminum. The crystal structure of the title compound was redetermined from single crystal X-ray diffraction data. The structure adopts ErNi3Al9 type, space group R32, parameters of the unit cell a ​= ​7.2838(2) Å, c ​= ​27.4004(8) Å. The growth of relatively large single crystals of the YNi3Al9 compound, having completely ordered structure, indicates possible existence of region on phase diagram, where the title compound is in equilibrium with liquid. Comparison with the results in the literature on the investigations of the same and related compounds shows trend towards formation of more ordered structures in flux grown samples and more disordered ones in arc melted samples. Physical properties of the title compound - electrical resistivity, magnetoresistance and heat capacity - were measured for the first time. It shows metallic-like behavior with very high values of magnetoresistance up to 420% at low temperatures without presence of magnetic elements. Therefore electronic structure calculations were carried out. The phonon heat capacity reveals major Debye and minor Einstein contributions at the intermediate temperatures, and total heat capacity approaches Dulong-Petit limit at high temperatures. The calculated Debye temperature from the whole temperature range θD ​= ​480(6) K is typical for aluminium-rich compounds. Corresponding Einstein temperature is θE ​= ​198(8) K. The estimations of electron-phonon coupling constant λ ​= ​0.092 show very weak coupling and absence of superconducting transition.

  • Structured deformation of granular material in the state of active earth pressure
    • Leśniewska Danuta
    • A. Tordesillas
    • Magdale Pietrzak
    • Shuo Zhou
    • Michał Nitka
    2023 COMPUTERS AND GEOTECHNICS

    The paper focuses on the ability of granular materials to undergo structured deformation by analysing the data from the retaining wall model tests and discrete element simulations. The structured deformation means the movement of a granular material which produces a stable, regular pattern of multiple shear bands. The paper's primary purpose is to study this kind of deformation for the selected data representing the state of active earth pressure of granular materials. The locations of high and negligible shear strains (shear zones and 'dead' zones) in the displacement fields are determined using the shear strains definition. A recently introduced metric called s-LID, expressing the perspective of collective grain motion, is applied to the same data. The s-LID analysis finds the detailed structure of the localisation pattern directly from displacement data without using the continuum mechanics concept of strains. It is entirely consistent with the digital image correlation analysis in the areas of significant displacement. It expands the knowledge of the deformation structure in small displacement areas, where the digital image correlation method loses its capability. Low s-LID and point-like representations in the displacement state space identify nearly rigid zones in the area of high displacements.

  • Structure-Property Relationship and Multiple Processing Studies of Novel Bio-Based Thermoplastic Polyurethane Elastomers
    • Joanna Smorawska
    • Marcin Włoch
    • Ewa Głowińska
    2023 Pełny tekst Materials

    Currently, the growing demand for polymeric materials has led to an increased need to develop effective recycling methods. This study focuses on the multiple processing of bio-based thermoplastic polyurethane elastomers (bio-TPUs) as a sustainable approach for polymeric waste management through mechanical recycling. The main objective is to investigate the influence of two reprocessing cycles on selected properties of bio-TPUs. Two series of bio-based TPUs were synthesized via a solvent-free two-step method with the use of hexamethylene diisocyanate or hexamethylene diisocyanate/partially bio-based diisocyanate mixtures, bio-based poly(triamethylene ether) glycol, and bio-based 1,3 propanediol. Both the raw bio-TPUs and those subjected to two reprocessing cycles were examined with respect to their chemical, physical, thermal, thermomechanical, and mechanical properties. The conducted research revealed that reprocessing led to changes in the phase separation between the hard and soft segments, thereby affecting the bio-TPUs’ properties. Both series of materials showed similar chemical structures regardless of reprocessing (slight changes were observed in the range of carbonyl peak). The thermal properties of TPUs exhibited slight differences after each reprocessing cycle, but generally, the non-processed and reprocessed bio-TPUs were thermally stable up to about 300 °C. However, significant differences were observed in their mechanical properties. The tensile strength increased to 34% for the twice-reprocessed bio-TPUs, while the elongation at break increased by ca. 200%. On the other hand, the processing cycles resulted in a decrease in the hardness of both bio-TPU series (ca. 3–4 °ShA). As a result, the prepared bio-TPUs exhibited characteristics that were closer to those of the sustainable materials model, promoting the circular economy of plastics, with environmental benefits arising from their recyclability and their high content of bio-based monomers (78.4–78.8 wt.%).

  • Study of Soil Temperature and Moisture Changes in a Physical Model of an Underground Cable Line
    • Stanisław Czapp
    • Filip Ratkowski
    • Seweryn Szultka
    • Krzysztof Szuchnik
    • Michał Kołtun
    2023

    The ampacity of power cables is highly dependent on the thermal resistivity of the soil in which they are laid. The lower it is, the higher this ampacity. The thermal resistivity of the soil decreases as its moisture increases. Therefore, it is preferable that the soil around the cables has high moisture. Unfortunately, the heat generated in heavily loaded cables causes the migration of moisture from the surrounding soil, which adversely affects the ampacity of these cables. However, it turns out that it is possible to stop the migration of moisture from the immediate vicinity of the cables. The paper presents the results of a long-term experiment (soil/betonite temperature and moisture measurements), which proves that proper protection of the medium around the cables makes it possible to stop the migration of moisture. This has a positive effect on the ampacity of the cables and, thus, on the level of transmitted power.

  • Study of various machine learning approaches for Sentinel-2 derived bathymetry
    • Andrzej Chybicki
    • Paweł Sosnowski
    • Marek Kulawiak
    • Tomasz Bieliński
    • Waldemar Korlub
    • Zbigniew Łubniewski
    • Magdalena Kempa
    • Jarosław Parzuchowski
    2023 Pełny tekst PLOS ONE

    In recent years precise and up-to-date information regarding seabed depth has become more and more important for companies and institutions that operate on coastlines. While direct, in-situ measurements are performed regularly, they are expensive, time-consuming and impractical to be performed in short time intervals. At the same time, an ever-increasing amount of satellite imaging data becomes available. With these images, it became possible to develop bathymetry estimation algorithms that can predict seabed depth and utilize them systematically. Since there are a number of theoretical approaches, physical models, and empirical techniques to use satellite observations in order to estimate depth in the coastal zone, the presented article compares the performance and precision of the most common one to modern machine learning algorithms. More specifically, the models based on shallow neural networks, decision trees and Random Forest algorithms have been proposed, investigated and confronted with the performance of pure analytical models. The particular proposed machine learning models differ also in a set of satellite data bands used as an input as well as in applying or not geographical weighting in the learning process. The obtained results point towards the best performance of the regression tree algorithm that incorporated as inputs information about data localization, raw reflectance data from four satellite data bands and a quotient of logarithms of B2 and B3 bands. The study for the paper was performed in relatively optically difficult and spatially variant conditions of the south Baltic coastline starting at Szczecin, Poland on the west (53˚26’17’’ N, 14˚32’32’’ E) to Hel peninsula (54˚43’04,3774’’ N 18˚37’56,9175’’ E). The reference bathymetry data was acquired from Polish Marine Administration. It was obtained through profile probing with single-beam sonar or direct in-situ probing.

  • Study of ZrS3-based field-effect transistors toward the understanding of the mechanisms of light-enhanced gas sensing by transition metal trichalcogenides
    • Katarzyna Drozdowska
    • Adil Rehman
    • Sergey Rumyantsev
    • Michelle Wurch
    • Ludwig Bartels
    • Alexander Balandin
    • Janusz Smulko
    • Grzegorz Cywiński
    2023 Pełny tekst Materials Today Communications

    Extending knowledge of the properties of low-dimensional van der Waals materials, including their reactivity to the ambiance, is important for developing innovative electronic and optoelectronic devices. Transition metal trichalcogenides with tunable optical band gaps and anisotropic conductivity are an emerging class among low- dimensional structures with the possibility of gate tunability and photoreactivity. These properties can be combined into light-enhanced field-effect transistor gas sensors. We demonstrated prototype zirconium trisulfide (ZrS3) sensors for nitrogen dioxide, ethanol, and acetone. Photoconductivity and photogating play a critical role in photoinduced gas sensing, with the dominance of the first for blue (470 nm) and green (515 nm) and the second one prevailing for red (700 nm) irradiations. Our results suggest that surface trap states lead both to trapping and scattering of the charge carriers in the channel. The gas detection is guided by charge transfer and modulation of the carrier mobility, resulting in distinct I-V characteristics for selected irradiation conditions.

  • Study on effective front region thickness of PCM in thermal energy storage using a novel semi-theoretical model
    • Rafał Andrzejczyk
    • Muhammad Saqib
    • Tomasz Kowalczyk
    • Hafiz Muhammad Ali
    2023 Pełny tekst INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER

    Thermal energy storage in mobile applications, particularly battery of electric vehicles, is currently gaining a lot of importance. In this paper, a semi-theoretical time-dependent mathematical model of the phase change in a double shell thermal energy storage module has been developed where the inner tube is a heat exchange surface. An effective front region thickness for the melting and solidification process has been studied. The proposed model is calibrated based on our experimental data. The purpose of such a model is to enable the optimization of the geometry of the energy storage modules in terms of the PCM to the TES container mass ratio and enhancement of phase change rate. In addition, results obtained for a single tube can be used in the bundle of tubes in shell and tube TES design. The results have shown that for the larger diameter of the module (smaller difference between the working tube and shell diameter) the optimal working time is around 2000 s.

  • Study on Microstructure-Property Relationship of Inconel 617 Alloy/304L SS Steel Dissimilar Welds Joint
    • Amit Kumar
    • Krishna Guguloth
    • Shailesh M. Pandey
    • Dariusz Fydrych
    • Sachin Sirohi
    • Chandan Pandey
    2023 METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE

    Welding of Inconel 617 (IN617) alloy and austenitic 304L SS steel has been attempted using the autogenous Laser Beam Welding (LBW) process. Characterization of dissimilar weldments was performed on either side of the fusion boundaries. The metallographic results showed that the inhomogeneous microstructure formation for weld metal contained columnar and cellular dendrites near the interface, whilst the columnar, cellular and equiaxed types of dendrites were in the weld centre. The energy dispersive spectroscopy (EDS) and electron probe microanalysis (EPMA) studies revealed the white layer near the interface on both sides of the fusion line, as well as a significant change in the concentration of alloying elements (Fe, Cr, Ni, Co, and Mo). The weld metal accompanied by Cr, Ti and Mo precipitates evolved in the inter-dendritic spaces. The Cr and Mo-rich M23C6 and Mo-rich M6C phases in IN617 heat-affected zone (HAZ) were found in SEM/EDS and EPMA studies. The 304L SS side showed a distinct HAZ, whilst on the IN617 side, no distinct HAZ was seen. Samples were prepared from the dissimilar weldments to evaluate their mechanical properties, such as tensile strength and hardness. The microhardness plot showed the non-uniformity in hardness along the weldments. The weld metal hardness was 253 ± 10 HV. The tensile test of the welded joint results was compared with the base metals. The tested results exhibited that the failure of the specimen from 304L SS base metal (BM) or from weld metal with tensile strength was marginally lower than the Inconel 617 base metal but significantly higher than the 304L SS BM. The fracture surface study revealed the presence of Mo and Cr segregation in inter-dendritic spaces, which impoverished the tensile properties. The order of impact toughness was measured as follows: 304L SS BM > 304L SS HAZ>IN617 BM>weld metal>IN617 HAZ. The IN617 HAZ was recognised as the weakest area of the weldments in terms of impact strength. The welded joint was considered safe for AUSC application because the stress-rupture properties were evaluated in between base metals data.

  • Study on transmission quality in cellular 4G and 5G networks between 2019–2021: Impact of the COVID-19 pandemic on the level of provided services by operating base transceiver stations
    • Przemysław Falkowski-Gilski
    • Tadeus Uhl
    2023 Pełny tekst Zeszyty Naukowe Akademii Morskiej w Szczecinie

    The COVID-19 pandemic has significantly limited user mobility, not least among students. Remote learning had a particular impact on resource allocation in relation to using terrestrial cellular networks, especially 4G systems in urban agglomerations. This paper presents the results of a quality evaluation of an outdoor environment, carried out between 2019 and 2021 on the campus of a technical university. Annual studies are conducted using our own custom-built mobile application, installed on 50 mobile devices (i.e., smartphones) running Android OS. This study aims to determine the impact of reduced user mobility on access parameters in mobile networks, that is, both download and upload throughput as well as delay (ping), with a particular focus on serving base transceiver stations (BTSs). This research scenario involves long-term evolution (LTE) compatible user equipment (UE) that operates under four Polish mobile network operators (MNO), which includes roaming connections and the newly launched 5G standard.

  • Substancje groźne, niebezpieczne i pożyteczne. Tom 2. Związki organiczne
    • Aleksander Kołodziejczyk
    • Aleksandra Kołodziejczyk
    2023

    Streszczenie W drugim tomie prezentowanej książki przedstawione zostały informacje nt. związków organicznych, ich występowania, otrzymywania, właściwości oraz zagrożeń jakie one stwarzają, a także korzyści, jakich dostarczają. Do związków organicznych zaliczane są te substancje, które zawierają atom lub atomy węgla, z pewnymi wyjątkami (szczegóły w książce). Szacunkowo, liczba znanych związków organicznych sięga kilkudziesięciu milionów (wg PubChem), a rocznie przybywa ich około 200 tys. W związkach organicznych obok węgla i wodoru najczęściej występują także tlen, azot i siarka, dlatego te pięć pierwiastków nazwano pierwiastkami organicznymi. Połączenia organiczne, które zawierają jeszcze inne atomy bezpośrednio związane z atomami węgla noszą nazwy wynikające z ich obecności np. związki z atomami metali nazywane są związkami metaloorganicznymi. Do najczęściej spotykanych należą też związki halogenoorganiczne, siarkoorganiczne czy fosforoorganiczne. Od ich nazw zatytułowane zostały poszczególne rozdziały książki. Z racji bardzo zróżnicowanych edukacyjnie potencjalnych czytelników książki poprzedzono je omówieniem głównych grup związków organicznych, a więc węglowodorów, alkoholi, eterów, związków karbonylowych, kwasów karboksylowych i ich pochodnych. Szczególny nacisk został położony na zagrożenia, jakie stwarzają najniebezpieczniejsze z nich, a także sposoby ochrony przed nimi. Przed przystąpieniem do pisania tej książki z niektórych zagrożeń nie zdawali sobie sprawy nawet jej autorzy, chemicy organicy z długoletnim doświadczeniem. Przykładem może być eteromania, nałóg narkotyzowania się eterem dietylowym, bardzo rozpowszechniony w okresie międzywojennym. Znamiennym przykładem ogromnego zagrożenia jest siarczan dimetylu, popularny odczynnik używany w laboratoriach chemicznych i biochemicznych. Powszechnie wiadomo, że jest to substancja szkodliwa, ale mało kto wie jak bardzo – był rozważany jako potencjalny gaz bojowy.

  • Succinite, Baltic Amber: A Chemical Masterpiece of Nature
    • Ewa Wagner-Wysiecka
    2023 Pełny tekst Journal of Gems & Gemmology

    Succinite, Baltic amber, is one of the most appreciated fossil resins. Its beauty has fascinated people since prehistoric times. It is a substance, and also gemstone, whose uniqueness is due to its compelling, though still not fully understood, physicochemical nature. In this article, some facts about the physical and chemical properties of succinite in order to find an answer for questions about the unique properties of this resin, such as color, transparency, texture etc., are discussed. These properties are among the factors that determine the choice of Baltic amber as a gemstone. Commonly known properties of succinite, but also some less obvious features, have been linked to the organic and inorganic chemical composition and structural factors, including the sophisticated supramolecular structure masterfully created by nature. Changes of the properties of succinite used as a jewelry stone are discussed as a reflection of changes in its physicochemical nature. In this light, some methods that can be used to identify succinite (i.e., infrared spectroscopy and nuclear magnetic resonance spectroscopy) and their relevance to the classification of fossil resins are briefly discussed. This article highlights an important point: only by understanding the chemical and physical nature of the material we able to identify, modify and effectively use the goods that have been given to us by mother nature.

  • Suitableness of SLM Manufactured Turbine Blade for Aerodynamical Tests
    • Janusz Telega
    • Piotr Kaczynski
    • Małgorzata Śmiałek-Telega
    • Piotr Pawłowski
    • Ryszard Szwaba
    2023 Pełny tekst Materials

    settingsOrder Article Reprints Open AccessArticle Suitableness of SLM Manufactured Turbine Blade for Aerodynamical Tests by Janusz Telega 1,*ORCID,Piotr Kaczynski 1ORCID,Małgorzata A. Śmiałek 2ORCID,Piotr Pawlowski 3ORCID andRyszard Szwaba 1ORCID 1 Institute of Fluid Flow Machinery Polish Academy of Sciences (IMP PAN), Fiszera 14, 80-231 Gdansk, Poland 2 Faculty of Mechanical Engineering and Ship Technology, Institute of Naval Architecture and Ocean Engineering, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk, Poland 3 Institute of Fundamental Technological Research Polish Academy of Sciences (IPPT PAN), Pawinskiego 5B, 02-106 Warsaw, Poland * Author to whom correspondence should be addressed. Materials 2023, 16(7), 2866; https://doi.org/10.3390/ma16072866 Received: 27 February 2023 / Revised: 24 March 2023 / Accepted: 29 March 2023 / Published: 4 April 2023 (This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications) Download Browse Figures Versions Notes Abstract This paper describes some insights on applicability of a Selective Laser Melting and Direct Metal Laser Sintering technology-manufactured turbine blade models for aerodynamic tests in a wind tunnel. The principal idea behind this research was to assess the possibilities of using ‘raw’ DLMS printed turbine blade models for gas-flow experiments. The actual blade, manufactured using the DLMS technology, is assessed in terms of surface quality (roughness), geometrical shape and size (outline), quality of counterbores and quality of small diameter holes. The results are evaluated for the experimental aerodynamics standpoint. This field of application imposes requirements that have not yet been described in the literature. The experimental outcomes prove the surface quality does not suffice to conduct quantitative experiments. The holes that are necessary for pressure measurements in wind tunnel experiments cannot be reduced below 1 mm in diameter. The dimensional discrepancies are on the level beyond acceptable. Additionally, the problem of ‘reversed tolerance’, with the material building up and distorting the design, is visible in elements printed with the DLMS technology. The results indicate the necessity of post-machining of the printed elements prior their experimental usage, as their features in the ‘as fabricated’ state significantly disturb the flow conditions.

  • Superconductivity in a breathing kagome metals ROs2 (R = Sc, Y, Lu)
    • Karolina Górnicka
    • Michał Winiarski
    • Dorota I. Walicka
    • Tomasz Klimczuk
    2023 Pełny tekst Scientific Reports

    We have successfully synthesized three osmium-based hexagonal Laves compounds ROs2 (R = Sc, Y, Lu), and discussed their physical properties. LeBail refinement of pXRD data confirms that all compounds crystallize in the hexagonal centrosymmetric MgZn2- type structure (P63/mmc, No. 194). The refined lattice parameters are a = b = 5.1791(1) Å and c = 8.4841(2) Å for ScOs2, a = b = 5.2571(3) Å and c = 8.6613(2) Å for LuOs2 and a = b = 5.3067(6) Å and c = 8.7904(1) Å for YOs2. ROs2 Laves phases can be viewed as a stacking of kagome nets interleaved with triangular layers. Temperature-dependent magnetic susceptibility, resistivity and heat capacity measurements confirm bulk superconductivity at critical temperatures, Tc, of 5.36, 4.55, and 3.47 K for ScOs2, YOs2, and LuOs2, respectively. We have shown that all investigated Laves compounds are weakly-coupled type-II superconductors. DFT calculations revealed that the band structure of ROs2 is intricate due to multiple interacting d orbitals of Os and R. Nonetheless, the kagome-derived bands maintain their overall shape, and the Fermi level crosses a number of bands that originate from the kagome flat bands, broadened by interlayer interaction. As a result, ROs2 can be classified as (breathing) kagome metal superconductors

  • Superconductivity in Bismuth Pyrochlore Lattice Compounds RbBi2 and CsBi2: The Role of Relativistic Effects
    • Sylwia Gutowska
    • Bartlomiej Wiendlocha
    • Tomasz Klimczuk
    • Michał Winiarski
    2023 Pełny tekst Journal of Physical Chemistry C

    Superconducting properties of two bismuthide intermetallic compounds, RbBi2 and CsBi2, were studied by means of experimental measurements and ab initio calculations. We show that in both compounds, the superconductivity emerges from the pyrochlore Bi lattice and its formation is heavily influenced by relativistic effects. Based on our analysis of the effect of spin–orbit coupling on the electron–phonon coupling, we suggest a possible criterion for finding new superconducting materials by looking for structures featuring relativistically stabilized hypervalent networks of heavy p-block elements.

  • Superconductivity of Ta-Hf and Ta-Zr alloys: Potential alloys for use in superconducting devices
    • Tomasz Klimczuk
    • Szymon Królak
    • Robert J. Cava
    2023 Pełny tekst Physical Review Materials

    The electronic properties relevant to superconductivity are reported for bulk Ta-Hf and Ta-Zr body centered cubic alloys, in a large part to determine whether their properties are suitable for potential use in superconducting qbits. The body centered cubic unit cell sizes increase with increasing alloying. The results of magnetic susceptibility, electrical resistivity, and heat capacity characterization are reported. While elemental Ta is a type I superconductor, the alloys are type II strong coupling superconductors. Although decreasing the electron count per atom is expected to increase the density of electronic states at the Fermi level and thus the superconducting transition temperature (Tc) in these systems, we find that this is not sufficient to explain the significant increases in the superconducting Tc’s observed.

  • Superhydrophobic and superoleophilic melamine sponges impregnated with deep eutectic solvents for oil spill cleanup
    • Patrycja Makoś-Chełstowska
    • Edyta Słupek
    2023 SEPARATION AND PURIFICATION TECHNOLOGY

    The extensive extraction of oil from the bottom of seas and oceans and its transportation by tankers increase the risk of potential environmental disasters associated with hydrocarbon fractions entering water reservoirs. Therefore, this paper presents the preparation of a simple impregnation of a melamine sponge with deep eutectic solvents (DES), which can be obtained from natural sources, including coconut oil, palm kernel oil, seed oils, mammalian milk, and substances commonly used in pharmacological and physiological studies. A preselection method based on the COSMO-RS model was used to select the most suitable DES among 760 solvents. The selected DES were prepared and impregnated on melamine sponge (MS). Structural and surface analyses were performed by DES-MS. The process parameters that affect the sorption capacity of DES-MS and the affinity tests were performed for specific oil groups. The highest absorption capacities were obtained for MS impregnated with tetraethylammonium chloride and decanoic acid in a 1:2 M ratio. The prepared new DES-MS were characterized by very high sorption capacities ranging from 40.9 to 99.8 g/g, as well as superhydrophobicity (water contact angle 151°), superoleophobicity (oil contact angle 0°), low density (0.177 g/cm3), high porosity (88.25 %), high thermal, mechanical, and chemical stability, and the possibility of multiple regenerations without loss of sorption capacity. In addition, the preparation of DES-MS is simple and involves little time and consumption of toxic organic solvents. These results indicate that DES-MS may be a “green” and low-cost alternative to current approaches for removing oil from water.

  • Suppressors of lapC mutation identify new regulators of LpxC, which mediates the first committed step in lipopolysaccharide biosynthesis
    • Akshay Maniyeri Suresh
    • Alicja Wieczorek
    • Aravind Ayyolath
    • Weronika Sugalska
    • Gracjana Klein-Raina
    • Satish Raina
    2023 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Gram-negative bacteria, such as Escherichia coli, are characterized by an asymmetric outer membrane (OM) with lipopolysaccharide (LPS) located in the outer leaflet and phospholipids facing the inner leaflet. E. coli recruits LPS assembly proteins LapB, LapC and LapD in concert with FtsH protease to ensure a balanced biosynthesis of LPS and phospholipids. We recently reported that bacteria either lacking the periplasmic domain of the essential LapC protein (lapC190) or in the absence of LapD exhibit an elevated degradation of LpxC, which catalyzes the first committed step in LPS biosynthesis. To further understand the functions of LapC and LapD in regulating LPS biosynthesis, we show that the overproduction of the intact LapD suppresses the temperature sensitivity (Ts) of lapC190, but not when either its N-terminal transmembrane anchor or specific conserved amino acids in the C-terminal domain are mutated. Moreover, overexpression of srrA, marA, yceJ and yfgM genes can rescue the Ts phenotype of lapC190 bacteria by restoring LpxC amounts. We further show that MarA-mediated suppression requires the expression of mla genes, whose products participate in the maintenance of OM asymmetry, and the SrrA-mediated suppression requires the presence of cardiolipin synthase A.

  • Surfactants application in sample preparation techniques: Insights, trends, and perspectives
    • Khrystyna Vakh
    • Stanislawa Koronkiewicz
    2023 TRAC-TRENDS IN ANALYTICAL CHEMISTRY

    Since the implementation of Green Chemistry into analytical practice, significant efforts have been made to improve the sustainability of chemical analysis. These include reducing the use of hazardous chemicals and solvents, minimizing waste, and improving energy efficiency. Surfactants can be applied in chemical analysis as an environmentally friendly alternative to conventional solvents and chemicals. The use of surfactants can increase extraction efficiency by improving solubility, increasing selectivity, and reducing organic solvent consumption. In addition, surfactants can also reduce interference with the sample matrix and improve limits of detection. This review covers recent developments in surfactant-based extraction techniques, highlighting the use of surfactants in both liquid-phase and solid-phase extraction. The main principles of surfactant-based extraction methods are discussed, as well as their application as assisting agents or surface modifiers. The effects of deep eutectic solvents on surfactants micellization and the application of biocompatible surfactants are also discussed.

  • Suspended-sediment transport related to ice-cover conditions during cold and warm winters, Toudaoguai stretch of the Yellow River, Inner Mongolia, China
    • Shui-Xia Zhao
    • Quancheng Zhou
    • Wen-Jun Wang
    • Ying-Jie Wu
    • Chao Lin
    • Qiang Quan
    • Parisa Radan
    • Youcai Tuo
    • Tomasz Kolerski
    2023 Pełny tekst ECOLOGICAL INDICATORS

    The presence of winter ice in cold regions changes the water level, flow rate, velocity distribution, and other parameters of the river, which in turn affects the sediment concentration and channel evolution. Based on data obtained from Toudaoguai Hydrological Station from 1959 to 2021, this study examines the characteristics of the ice regime during cold and warm winters and the water and sediment transport processes along the Yellow River in Inner Mongolia in the context of climate change. The Mann–Kendall test and trend analysis were applied to define the years of temperature mutations and their trends, and the temperature mutation point was determined to be the 1987/1988 season. The study considers the effect of climate change on the combination of hydrological and hydraulic conditions. Therefore, trends in suspended sediment transport, ice type formation, water discharge, and storage in different ice flood seasons (November 1 to March 31, from 1998 to 2021) were attained. Based on the cumulative negative air temperature, winters were categorized into three types, warm, normal, and cold (52.2%, 17.4%, and 30.4%, respectively). Strong and weak grades further divide cold and warm winters, and statistical analyses were used to examine the characteristics of ice, water discharge, channel storage, and sediment transport. The duration of open water, freeze-up, ice cover, and breakup periods were calculated, and the relationship between the suspended sediment transport rate and discharge rate in these various ice periods was defined. The obtained relations show that the suspended sediment rate during the ice cover and first drift was smaller than that during the open water and post-breakup conditions. For the ice cover period, the sediment transport rate was on average approximately four times smaller than the freeze-up condition and six times smaller than the open water condition. The reduced sediment transport rate in the freeze-up period can be attributed to the weakened vertical turbulent mixing and increased flow resistance.

  • Sustainability objectives and collaboration lifecycle in cluster organizations
    • Anna Lis
    • Małgorzata Rozkwitalska
    • Adrian Lis
    2023 Pełny tekst Quality and Quantity

    In our paper, we combine two issues, collaboration in cluster organizations and sustainability, aiming to answer the question: Does complex governance structure of cluster organizations support members in formulating and reaching sustainability objectives? Based on four case studies of cluster organizations and a still novel abductive approach, we present the ways in which sustainability was executed in their functioning. Our study shows that the role of cluster organizations in formulating and reaching sustainability objectives varied with regard to their collaboration life cycle. The “Formation” stage laid the foundations for collaboration and relational governance, the “Growth” stage aimed at improving the economic performance of cluster members, while the “Extension” stage impacted more cluster stakeholders with regard to the economic, social and environmental sustainability objectives. Nevertheless, stakeholders' self-interest induced collaboration, whereas relational governance was its essential feature. Moreover, the potential of cluster organizations' governance structures was not fully exploited in the context of sustainability, their structures have played a role in raising awareness, but it was more the competitive factors that drove companies to engage in an activity because they wanted to stay in the market, change the conditions and keep up with trends. Our research also provides practical implications for various cluster organizations’ stakeholders.

  • Sustainable bioethanol production from first- and second-generation sugar-based feedstocks: Advanced bibliometric analysis
    • Claudia Elisa Cesar Guimaraes
    • Francisco Simao Neto
    • Viviane de Castro Bizerra
    • Jean Gleison Andrade do Nascimento
    • Roberta Bussons Rodrigues Valério
    • Paulo Gonçalves de Sousa Junior
    • Rafael Leandro Fernandes Melo
    • Ada Amelia Sanders Lopes
    • Ajay S. Desai
    • Muhammad Bilal
    • Wojciech Smułek
    • Teofil Jesionowski
    • José Cleiton Sousa dos Santos
    2023 Bioresource Technology Reports

    Bioethanol is produced from carbohydrate-containing feedstocks through fermentation. Based on a bibliometric review of studies published between 2012 and 2021, we analyzed those on sustainable bioethanol production. The Web of Science main collection yielded 1647 publications, which were analyzed using VOSViewer, CiteSpace, and ArcMap software. More than half of these publications originated from some Asian countries, corresponding to 63.6 %, with India being the most participatory country. The most studied area was energy fuels, and Bioresource Technology (Elsevier) was the journal that published most on the topic, while Universiti Tenaga Nasional in Malaysia had the most interactions. Four emerging trends were identified, in mention: enzymatic hydrolysis, alternative process arrangements, use of the bacterium Zymomonas mobilis and structural features. In conclusion, it was found that the studies generally identified more advantages than disadvantages, and the research showed a positive trend, but there are still existing obstacles, which may be overcome through improved processes.