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Gdańsk University of Technology

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  • Multi-instrument analysis of L-band amplitude scintillation observed over the Eastern Arabian Peninsula
    • Abdollah Masoud Darya
    • Muhammad Mubasshir Shaikh
    • Grzegorz Nykiel
    • Essam Ghamry
    • Ilias Fernini
    2024 ADVANCES IN SPACE RESEARCH

    The study of scintillation-causing ionospheric irregularities is important to mitigate their effects on satellite communications. It is also important due to the spatial and temporal variability of these irregularities, given that their characteristics differ from one region to another. This study investigates the spatial and temporal characteristics of L1 amplitude scintillation-causing ionospheric irregularities over the Eastern Arabian Peninsula during the ascending phase of solar cycle 25 (years 2020–2023). The temporal occurrences of weak and strong scintillation were separated by sunset, with weak scintillation observed predominantly pre-sunset during the winter solstice and strong scintillation observed mainly post-sunset during the autumnal equinox. Strong scintillation was much more pronounced in 2023 compared to the other three years, indicating a strong influence of solar activity. Spatially, weak-scintillation-causing irregularities exhibited a wide distribution in azimuth and elevation, while strong-scintillation-causing irregularities were concentrated southwards. The combined analysis of S4 and rate of total electron content index (ROTI) suggested that small-scale ionospheric irregularities were present in both pre- and post-sunset periods, while large-scale irregularities were only seen during the post-sunset period. Furthermore, the presence of southward traveling ionospheric disturbances (TIDs) during the 2023 autumnal equinox was confirmed with the total electron content anomaly (dTEC), while the Ionospheric Bubble Index (IBI) provided by the Swarm mission was unable to confirm the presence of equatorial plasma bubbles during the same period. Observations from the FORMOSAT-7/COSMIC-2 mission indicated that strong-scintillation-causing irregularities were more prevalent under the F2-layer peak, while the weak-scintillation-causing irregularities were mostly observed at the E-layer, F2-layer, and above the F2-layer. This study aims to contribute insights into the behavior of scintillation-causing ionospheric irregularities in the region, with implications for future research during the peak of the 25th solar cycle.

  • Multilayer coatings based on cerium oxide and manganese cobaltite spinel for Crofer22APU SOC interconnects
    • Elisa Zanchi
    • Justyna Ignaczak
    • Grzegorz Cempura
    • Sebastian Molin
    • Aldo R. Boccaccini
    • Federico Smeacetto
    2024 MATERIALS LETTERS

    The current state of the art steel interconnect coating materials are based on critical raw material - Co-oxide spinels. Replacing Co-oxide spinels with alternative, abundant materials can reduce the dependence on the critical raw materials. Cobalt-free coatings with the general formula Mn2-xCuFexO4, where x = 0, 0.1, 0.3, were electrophoretically deposited on a ferritic stainless-steel support and evaluated. Prior to deposition, the powders were prepared by a soft chemistry process and studied in terms of crystallographic phase analysis, electrical conductivity, thermal expansion, and sinterability behaviour. Coated steel samples were oxidised in an air atmosphere at 750 °C for 3000 h. In parallel, a state-of-the-art MnCo2O4 spinel oxide was tested as a reference. The coatings and oxide scale microstructures of the surfaces and cross-sections were examined by XRD, and SEM-EDX. TEM-EDX, XRF, and micro-XRD were also performed on the cross-section lamellae. The electrical properties of the steel-coating system were evaluated by Area Specific Resistance measurement. The results confirm that Mn–Cu–Fe oxides exhibit higher conductivity and lower TEC than Mn–Co oxide. Based on the obtained results, it might be concluded that the proposed coatings are a promising alternative to coatings that contain cobalt.

  • Multimodal analysis of traction forces and the temperature dynamics of living cells with a diamond-embedded substrate
    • Tomasz Kołodziej
    • Mariusz Mrózek
    • Saravanan Sengottuvel
    • Maciej Głowacki
    • Mateusz Ficek
    • Wojciech Gawlik
    • Zenon Rajfur
    • Adam M. Wojciechowski
    2024 Full text Biomedical Optics Express

    Cells and tissues are constantly exposed to chemical and physical signals that regulate physiological and pathological processes. This study explores the integration of two biophysical methods: traction force microscopy (TFM) and optically detected magnetic resonance (ODMR) to concurrently assess cellular traction forces and the local relative temperature. We present a novel elastic substrate with embedded nitrogen-vacancy microdiamonds that facilitate ODMR-TFM measurements. Optimization efforts focused on minimizing sample illumination and experiment duration to mitigate biological perturbations. Our hybrid ODMR-TFM technique yields TFM maps and achieves approximately 1 K precision in relative temperature measurements. Our setup employs a simple wide-field fluorescence microscope with standard components, demonstrating the feasibility of the proposed technique in life science laboratories. By elucidating the physical aspects of cellular behavior beyond the existing methods, this approach opens avenues for a deeper understanding of cellular processes and may inspire the development of diverse biomedical applications.

  • Multiscalar Control Based Airgap Flux Optimization of Induction Motor for Loss Minimization
    • Tadele Ayana
    • Marcin Morawiec
    • Lelisa Wogi
    2024 Full text IEEE Access

    Based on the induction motor model, considering the core loss resistance that accounts for magnetic characteristic saturation, a speed control approach is devised with an adaptive full-order (AFO) speed observer. The induction motor model analysis is done sincerely in a stationary reference frame. The control approach incorporates a flux reference generator designed to meet optimal operational circumstances and a nonlinear speed controller. The machine state variables are involved in flux generation and speed control rules. The performance of the proposed control strategy is formally studied by simulation and demonstrated through experiments. The technique exhibits fast convergence to the optimal flux level, reduces computational resource requirements, and enhances torque production and loss minimization accuracy. It eliminates the excessive flux demands compared to open-loop steady-state values, which will necessitate greater current levels without justification, resulting in an increased power dissipated. This optimum flux level minimizes induction motor losses for efficiency increments.

  • Multi-Taper-Based Automatic Correction of Non-Anechoic Antenna Measurements
    • Mariusz Dzwonkowski
    • Vorya Waladi
    • Adrian Bekasiewicz
    2024 Full text METROLOGIA

    Prototype measurements belong to the key steps in the development of antenna structures. Although accurate validation of their far-field performance can be realized in dedicated facilities, such as anechoic chambers, the high cost of their construction and maintenance might not be justified if the main goal of measurements is to support teaching or low-budget research. Instead, they can be performed in non-anechoic conditions and then refined using appropriate correction algorithms. Unfortunately, the existing post-processing methods suffer from multiple challenges that include manual setup of parameters as well as validation of performance in idealized conditions. In this communication, a multi-taper-based framework for correction of antenna characteristics obtained in non-anechoic environments has been proposed. The algorithm augments one-shot measurements of the structure under test in order to extract the line-of-sight responses while attenuating the interferences pertinent to multi-path propagation and noise from external sources of radiation. The performance of the proposed correction routine has been demonstrated in two test sites using a geometrically small Vivaldi radiator and validated against state-of-the-art techniques from the literature. The uncertainty budget for the measurements performed using the approach amounts to 0.26 dB, which is low given challenging propagation conditions considered for experiments.

  • Multitaper-Based Post-processing of Compact Antenna Responses Obtained in Non-anechoic Conditions
    • Mariusz Dzwonkowski
    • Adrian Bekasiewicz
    • Sławomir Kozieł
    2024

    The process of developing antenna structures typically involves prototype measurements. While accurate validation of far-field performance can be performed in dedicated facilities like anechoic chambers, high cost of construction and maintenance might not justify their use for teaching, or low-budget research scenarios. Non-anechoic experiments provide a cost-effective alternative, however the performance metrics obtained in such conditions require appropriate correction. In this paper, we consider a multitaper approach for post-processing antenna far-field characteristics measured in challenging, non-anechoic environments. The discussed algorithm enhances one-shot measurements to enable extraction of line-of-sight responses while attenuating interferences from multi-path propagation and the noise from external sources of electromagnetic radiation. The performance of the considered method has been demonstrated in uncontrolled conditions using a compact spline-based monopole. Furthermore, the approach has been favorably validated against the state-of-the-art techniques from the literature.

  • MXene-based composites for capacitive deionization – The advantages, progress, and their role in desalination - A review
    • Bakhtiar Ali Samejo
    • Kainat Naseer
    • Suraya Samejo
    • Farooque Janjhi
    • Najma Memon
    • Roberto Castro Munoz
    • Grzegorz Boczkaj
    2024 Full text Water Resources and Industry

    MXenes, a novel large family of 2D transition metal carbides, carbonitrides and nitrides are currently a “hot topic” in science due to their several fascinating physical and chemical properties. It follows from a rich diversity of their elemental compositions and chemical functionalities. MXenes can form composites with many substances, including polymers or metal oxides, which allows to effective “tune” MXene characteristics to a fit-to-the-purpose applications. Capacitive deionization (CDI) is currently widely studied as advanced desalination technique due to the advantages of cost-effectiveness, eco-friendly, and high salt removal capacity. One of key fields for CDI development relates to the ion's intercalation materials as concept taken from the sodium ion batteries, which is used in CDI because of their excellent desalination capacity. These materials provide effective sodium ions removal from the brine based on intercalation mechanism as well as redox reactions. In this review, we timely review an up-to-date accomplishment in the advancement of distinct MXene-based composite materials used as CDI electrodes, along with discussion of fundamental electrochemical energy storage mechanisms. The most relevant outcomes are highlighted together with the phenomena observed when applied in desalination applications. Finally, potential solutions as well as challenges in this field are summarized.

  • Nadmiarowe zgony podczas pandemii COVID-19 w Polsce i ocena skuteczności szczepień
    • Błażej Kochański
    • Jakub Sochacki
    2024 Full text Wiadomości Statystyczne

    Z powodu pandemii COVID-19 zmarły miliony ludzi na całym świecie. Jak wynika z wielu badań, szczepienia przeciw chorobie wywołanej wirusem SARS-CoV-2 okazały się środ-kiem ograniczającym skalę zachorowań i liczbę zgonów. Celem badania omawianego w artyku-le jest pomiar skali pandemii w Polsce za pomocą liczby nadmiarowych zgonów w podregio-nach według klasyfikacji NUTS 3 i w grupach wieku, a następnie określenie zależności pomiędzy zróżnicowaniem regionalnym względnej nadwyżki zgonów podczas czwartej fali pandemii a stopniem zaszczepienia populacji. Nadmiarowe zgony są rozumiane jako nadwyżka zgonów zarejestrowanych w stosunku do przewidywanego poziomu. Badaniem objęto okres od marca 2020 r. do lutego 2022 r. Korzystano z zasobów Eurostatu i Głównego Urzędu Statystycznego oraz danych pobranych z rządowego portalu Otwarte Dane. Analiza liczby nadmiarowych zgonów w podziale na grupy wieku wskazuje, że niemal 90% to zgony osób starszych (w wieku 60 lat i więcej). Z kolei pomiar w podziale na podregiony pozwala stwierdzić, że korelacja nadmiarowych zgonów i udziału zaszczepionych jest ujemna i dość silna. Przy założeniu występowania prostej regresji liniowej okazuje się, że dodatkowy 1% osób zaszczepionych w starszych grupach wieku przełożyłby się średnio na spadek liczby zgonów podczas czwartej fali pandemii o blisko 2000 w skali kraju. Ten wynik świadczy o tym, że szczepienia przeciw COVID-19 były skuteczne w zapobieganiu zgonom z powodu tej choro-by wśród osób starszych.

  • Nadzór i monitorowanie dostępności ZIntegrowanych Węzłów Przesiadkowych
    • Marcin Budzyński
    • Tomasz Mackun
    • Jacek Szmagliński
    • Romanika Okraszewska
    • Kazimierz Jamroz
    • Lech Michalski
    • Joanna Wachnicka
    2024

    Audyt dostępności dla planowanych, projektowanych i istniejących węzłów przesiadkowych musi być przeprowadzony w kontekście społecznym i prawnym, w którym re- alizowany jest projekt. W Polsce prawa osób z niepełnosprawnościami reguluje m.in. ustawa z dnia 19 sierpnia 1997 r. o rehabilitacji zawodowej i społecznej oraz zatrudnianiu osób niepełnosprawnych oraz ustawa z dnia 27 sierpnia 1997 r. o rehabilitacji społecznej i zawodowej oraz zatrudnianiu osób niepełnosprawnych. Obie ustawy określają prawa osób z niepełnosprawnościami, m.in. w zakresie dostępności do budynków i urządzeń użyteczności publicznej. Ponadto w Polsce obowiązuje ustawa z dnia 19 lipca 2019 r. o zapewnieniu dostępności osobom ze szczególnymi potrzebami. Ustawa ta nakłada na podmioty publiczne i prywatne obowiązek zapewnienia dostępności swoich usług, w tym węzłów przesiadkowych, dla osób o szczególnych potrzebach. W kontekście społecznym należy zwrócić uwagę na fakt, że osoby z niepełnosprawnościami stanowią znaczącą część społeczeństwa. Z danych Głównego Urzędu Statystycznego wynika, że w Polsce mieszka około 4,5 mln osób z niepełnosprawnościami. Dlatego projektowanie węzłów przesiadkowych musi uwzględniać potrzeby tej grupy osób. Warto również zwrócić uwagę na fakt, że projektowanie węzłów przesiadkowych i ich przekształcanie z myślą o dostępności dla osób o szczególnych potrzebach może wpłynąć pozytywnie na poprawę jakości życia całego społeczeństwa. Dostępność do transportu publicznego dla osób z niepełnosprawnościami może przyczynić się do zwiększenia ich aktywności i integracji ze społeczeństwem. W kontekście społecznym i prawnym audyt dostępności dla węzłów przesiadkowych jest nie tylko konieczny, ale również pozytywnie wpłynie na poprawę jakości życia osób z niepełnosprawnościami oraz całego społeczeństwa.

  • Nanofiltration-Assisted Concentration Processes of Phenolic Fractions and Carotenoids from Natural Food Matrices
    • Roberto Castro Munoz
    2024 Full text Separations

    In new food formulations, carotenoids and phenolic compounds are likely to be the most sought after food ingredients according to their bioactivity, nutraceutical, nutritional value, and compatibility properties once incorporated into food formulations. Such solutes are naturally present in many plant-based sources, and some portions are directly consumed when enriching food products and formulations; however, some portions, which are contained in the parts of the plant sources not considered edible, including the leaves, peel, and seeds, among other by-products, are commonly wasted. Related to this, scientists have found a new window for obtaining these bioactive molecules, but their recovery remains a challenge. To some extent, the final purification and polishing requires highly selective performance to guarantee the desired properties and concentration. In this regard, membrane technologies, such as nanofiltration (NF), represent an alternative, owing to their highly selective properties when separating low-molecular-weight compounds. NF becomes immediately suitable when the pretreated extracts are subjected to further efficient concentration, fractionation, and polishing of phenolic fractions and carotenoids. The separation efficiency (usually higher than 97%) of NF technology is high according to the low pore size of NF membranes, but the low temperature in process separation also contributes to the separation of thermolabile compounds. Therefore, this paper reviews the ongoing cases of studies reporting the successful separation and polishing of phenolic fractions and carotenoids from distinct sources. In particular, we have focused our attention on the main interactions during the separation process and the drawbacks and advantages of using membranes for such a case study.

  • Nanokrystaliczne tlenki metali jako katalizatory reakcji wydzielania tlenu w środowisku zasadowym
    • Krystian Lankauf
    2024 Full text

    W pracy poruszona została tematyka opracowania oraz zastosowania nanokrystalicznych tlenków metali jako katalizatorów reakcji wydzielania tlenu w elektrolicie zasadowym, tj. jednej z reakcji zachodzących podczas elektrolizy wody. Szczególną uwagę poświęcono tlenkom o strukturze spinelu i perowskitu, które znane są z wyjątkowych właściwości elektrycznych, magnetycznych, optycznych oraz katalitycznych. Materiały zostały przygotowane za pomocą metody zol żel lub wysokotemperaturowej syntezy w fazie stałej. Podjęte zostały próby modyfikacji materiałów poprzez wprowadzenie nowych pierwiastków do struktury krystalicznej czy zastosowanie dodatkowej obróbki cieplnej (wyżarzanie) lub mechanicznej (mielenie) w celu poprawy parametrów pracy katalizatora. Przeprowadzone zostały badania strukturalne za pomocą technik mikroskopowych i spektroskopowych, natomiast aktywność elektrokatalityczna była analizowana korzystając z pomiarów elektrochemicznych takich jak woltamperometria cykliczna czy elektrochemiczna spektroskopia i

  • Nanomateriały o właściwościach magnetycznych, fotokatalitycznych, biobójczych
    • Izabela Malinowska
    2024 Full text

    Tematyka badawcza pracy doktorskiej obejmuje preparatykę i charakterystykę nanomateriałów o właściwościach magnetycznych, fotokatalitycznych, biobójczych. Celem pracy była preparatyka nanomateriałów na bazie TiO2 oraz ZnFe2O4 oraz zastosowanie nanokompozytów w fotokatalizie heterogenicznej do degradacji ksenobiotyków niepodatnych na rozkład biologiczny i otrzymywania funkcjonalnych materiałów budowlanych. Otrzymane nanokompozyty scharakteryzowano za pomocą analizy powierzchni właściwej BET wraz z objętością porów, analizy rentgenograficznej XRD, analizy pętli histerezy magnetycznej oraz analizy mikroskopii elektronowej STEM. Otrzymane nanomateriały charakteryzują się właściwościami magnetycznymi, fotokatalitycznymi, biobójczymi. Taka hybrydowość właściwości pozwala na zastosowanie opisywanych materiałów jako fotokatalizatorów oraz dodatków do powszechnie znanych powłok ochronno-dekoracyjnych w celu nadania im nowych hybrydowych właściwości.

  • Nanoparticle-assisted biohydrogen production from pretreated food industry wastewater sludge: Microbial community shifts in batch and continuous processes
    • Mohamed Saad Hellal
    • Filip Gamoń
    • Grzegorz Cema
    • Gamal K. Hassan
    • Ginedy Mohamed Gehad
    • Aleksandra Ziembińska-Buczyńska
    2024 ENERGY CONVERSION AND MANAGEMENT

    Biohydrogen production from industrial waste has gained a significant attention as a sustainable energy source. In this study, the enrichment of biohydrogen production from pretreated dissolved air flotation (DAF) sludge, generated from food industry wastewater treatment plants, was investigated using SiO2@Cu-Ag dendrites cor- e–shell nanostructure (NS). The effect of NS on the changes of the microbial community and biohydrogen yield was evaluated through batch and continuous tests. In batch mode, various nanomaterial doses were investigated with several concentrations ranging from 20 to 50 mg/L for hydrogen production using glucose as a substrate. The optimum core–shell NS amount was 40 mg/L, achieving a maximum H2 yield of 163 mL/g volatile solids (VS) compared to the control’s 79 mL/g VS. However, 50 mg/L NS inhibited most bacteria in the sludge. The continuous experiment used a continuous stirring tank reactor (CSTR) with 40 mg/L SiO2@Cu-Ag core–shell NS and pretreated industrial sludge as substrate. The H2 yield increased to 115 L/kg VS compared to the control reactor’s 89 L/kg VS. The gas analysis showed compositional proportions of 83 % H2, 7 % CO2, and 4.5 % methane, while the microbial community analysis indicated the development of hydrogen-producing species such as Clostridium. In conclusion, SiO2@Cu-Ag core–shell NS addition enhanced anaerobic degradation of organic matter and its conversion to biohydrogen. The selected nanomaterial can be used for an effective continuous treatment system for industrial sludge while promoting dark fermentation.

  • Napęd z silnikiem indukcyjnym i 4-gałęziowym falownikiem SiC do turbosprężarek powietrza ogniw paliwowych dużej mocy
    • Marek Adamowicz
    • Sebastian Giziewski
    2024 Full text Przegląd Elektrotechniczny

    Wysoka cena ogniw paliwowych utrudnia ich szerokie zastosowanie w transporcie i przemyśle. Należy szukać możliwości obniżenia ich kosztu również poprzez obniżenie kosztu i zwiększenie wydajności urządzeń pomocniczych ogniwa paliwowego (Balance of the Plant). Autorzy proponują aby w napędzie sprężarki powietrza, zastosować wysokoobrotowy silnik indukcyjny, który jest tańszy od stosowanych obecnie silników PMSM. W referacie zaproponowano napęd z czterogałęziowym falownikiem SiC i wysokoobrotowym silnikiem indukcyjnym o mocy 6,3 kW, prędkości obrotowej 79 800 obr/min i częstotliwości zasilania 2667 Hz, który może być zastosowany do turbosprężarki powietrza ogniwa paliwowego o mocy 100 kW.

  • Natural/bio-based sorbents as greener extractive materials for endocrine disrupting compounds in samples of different matrix composition
    • Justyna Płotka-Wasylka
    • Aneta Chabowska
    • Suwijak Pantanit
    • Opas Bunkoed
    • Michel Y. Fares
    • Muhammad Sajid
    • Dimitra Lambropoulou
    • Aleksandra Kurowska-Susdorf
    • Natalia Jatkowska
    2024 Full text TRAC-TRENDS IN ANALYTICAL CHEMISTRY

    Endocrine-disrupting compounds (EDCs) are a group of chemicals that interfere with the endocrine system, leading to adverse effects on human health and the environment. Increasing concerns over the EDCs presence in various environmental compartments has driven the search for greener extraction materials. Recently, the use of polymers of natural origin (biopolymers) has been demonstrated to be an effective and promising research direction due to their undeniable advantages over synthetic polymers. In this review, strategies for cellulose, chitin, and chitosan functionalization and their applicability for numerous microextraction techniques have been widely discussed. Following the trend related to the reuse of waste, various agricultural wastes that were employed for the isolation and enrichment of EDCs are described. The benefits and limitations of using natural sorbents have been highlighted.

  • Nature-Inspired Driven Deep-AI Algorithms for Wind Speed Prediction
    • Muhammad Dilshad Sabir
    • Laiq Khan
    • Kamran Hafeez
    • Zahid Ullah
    • Stanisław Czapp
    2024 Full text IEEE Access

    Predicting wind energy production accurately is crucial for enhancing grid management and dispatching capacity. However, the inherent unpredictability of wind speed poses significant challenges to achieving high prediction accuracy. To address this challenge, this study introduces a novel pre-processing framework that leverages thirteen nature-inspired optimization algorithms to extract and combine Intrinsic Mode Functions (IMFs) of atmospheric and wind speed variables. The objective function ensures that the selected IMF combinations exhibit high correlation, enhancing their predictive relevance. The outputs of these algorithms are further refined using the proposed Optimal Search IMF (OAIMF) algorithm, which reduces redundancy and selects a minimal yet highly relevant set of IMF combinations for wind speed prediction. The methodology was validated through a case study conducted at the Climate, Energy, and Water Research Institute (CEWRI), NARC, Islamabad, Pakistan, leveraging real-world atmospheric data. Experimental results demonstrate that the proposed framework significantly outperforms direct prediction methods and state-of-the-art pre-processing techniques. For instance, the framework achieved an RMSE of 2.73 on an LSTM network and 3.86 on a GRU network, compared to RMSE values of 19.78 and 18.89, respectively, for direct prediction. Superior performance was also observed across MAE, MAPE, and R2 metrics. This study highlights the critical role of robust pre-processing in enhancing deep learning-based wind speed prediction. By integrating nature-inspired optimization with a novel IMF selection strategy, the proposed approach advances the state-of-the-art in renewable energy forecasting.

  • Nauka w świecie cyfrowym okiem młodego inżyniera - mobilne aplikacje cross-platformowe
    • Roman Dykyj
    • Julian German
    • Przemysław Falkowski-Gilski
    2024 Pismo PG

    Istotnym punktem w analizie technologii mobilnych jest poznanie opinii osób z nimi zaznajomionych. W niniejszym artykule przedstawione zostaną wyniki badań dotyczących porównania technologii cross-platformowych (uniwersalnych) i natywnych (dedykowanych), w których uwzględniono opinie i doświadczenia deweloperów pracujących w obszarze technologii mobilnych. Badanie miało na celu zrozumienie preferencji, wyzwań i korzyści związanych z wyborem odpowiedniej technologii w kontekście tworzenia aplikacji mobilnych.

  • Nauka w świecie cyfrowym okiem młodego inżyniera - nawigacja mobilna w miastach
    • Joanna Piotrowska
    • Łukasz Potrykus
    • Jakub Olszewski
    • Daria Cygańska
    • Przemysław Falkowski-Gilski
    2024 Pismo PG

    Dynamiczny rozwój technologii ICT i miniaturyzacja komponentów elektronicznych doprowadziły do sytuacji, w której znaczna część światowego społeczeństwa korzysta z urządzeń mobilnych. Dzięki powszechnemu dostępowi do smartfonów każdy użytkownik może w prosty sposób sprawdzić swoje położenie, niezależnie od tego, gdzie w danej chwili się znajduje. Ponadto sami operatorzy sieci komórkowych oraz dostawcy szeregu serwisów korzystają z informacji opartych na systemach satelitarnych GNSS (Global Navigation Satellite Systems), aby monitorować i doskonalić jakość oferowanych usług.

  • Nauka w świecie cyfrowym okiem młodego inżyniera – trendy w aplikacjach mobilnych
    • Roman Dykyj
    • Julian German
    • Przemysław Falkowski-Gilski
    2024 Pismo PG

    Aplikacje mobilne zyskały ogromną popularność wraz z postępem technologicznym i rozwojem telefonów komórkowych, które w dzisiejszych czasach nie są już wykorzystywane tylko do komunikacji za pomocą połączeń głosowych czy wiadomości SMS. Za pomocą smartfonów możemy dokonywać zakupów w Internecie, przeglądać sieci społecznościowe, wykonywać operacje bankowe. Ciągły rozwój tej dziedziny technologii daje szereg możliwości deweloperom tworzącym aplikacje mobilne.

  • Navigating the complexities of altruistic helping in Nonprofit Organizations: An analysis of Benefits, Burdens and managerial challenges
    • Joanna Szulc
    • Fabian Homberg
    2024 Public Management Review

    We investigate how individuals cope with side effects of altruistic behaviour at work, i.e. genuine helping behaviour which is not part of any job description, and what role the organizational context plays in these dynamics. Employing simultaneous dyadic interviews, we show how employees of non-profit organizations cope with undesired effects of altruistic help. Our data provides evidence of unintended outcomes for the individual which manifest in increased perceptions of emotional tension, problems with own work, and exploitation. We shed light on the involved mechanisms by analysing the psycho-emotional coping processes associated with helping behaviour. Implications for non-profit managers are discussed.

  • Navigating the Complexity: Understanding Social Integration in Smart Communities versus Smart Cities
    • Magdalena Ciesielska
    • Gabriela Viale-Pereira
    • Thomas J. Lampoltshammer
    2024 Full text

    This study delves into the differentiation between smart community and smart city concepts, employing a comprehensive review of conceptual literature. The aim of this study is to identify and deliberate on the nuanced disparities between these two paradigms. By establishing pivotal distinctions, we aim to scrutinize the integration of social aspects in the development and implementation of smart communities. Our findings will offer insights into the essential factors influencing individual and social behavioral changes, thereby facilitating the development of a conceptual model to guide future empirical investigations.

  • N-doped graphene quantum dot-decorated MOF-derived yolk-shell ZnO/NiO hybrids to boost lithium and sodium ion battery performance
    • Beata Bajorowicz
    • Monika Wilamowska-Zawłocka
    • Wojciech Lisowski
    • Andrzej Żak
    • Tomasz Klimczuk
    2024 APPLIED SURFACE SCIENCE

    Surface engineering at the nanoscale to obtain robust interface between metal oxides and quantum dots is essential for improving the performance and stability of battery materials. Herein, we designed and prepared novel N-doped graphene quantum dot-modified ZnO/NiO anode materials with a well-defined yolk-shell structure for lithium and sodium-ion batteries. NG QDs were assembled on the ZnO/NiO microspheres using three different coupling strategies: solvothermal, direct adsorption and annealing under N2 atmosphere. The presence of NG QDs deposited on the ZnO/NiO hybrids promoted enhanced electrical conductivity, lower chargetransfer resistance and provides more active sites. As a result, NG-ZnO/NiO_s anode obtained by solvothermal route exhibited high reversible delithiation capacity of 912 mAh/g at 18.6 mA g 1 and excellent cycling performance with the average delithiation capacity of 525 mAh/g at 372 mA g 1 over 400 cycles. Moreover, application of the NG-ZnO/NiO_s elecrode in Na-ion batteries revealed decent electrochemical behavior with capacity values reaching 235 mAh/g at 18.6 mA g 1. Importantly, surface properties, morphology and electrochemical behavior of obtained NG-ZnO/NiO hybrids were dependent on the combination route of NG QDs with ZnO/NiO microspheres indicating that quality of heterojunction between composite components has significant impact on the electrode performance.

  • Negative CO2 Emission Gas Power Plant As Technology for Utilization of Sewage Sludge, Production of Electrical Energy, and CO2 Capture - Case of Chamber Under Transpiration Cooling
    • Paweł Ziółkowski
    • Kamil Stasiak
    • Mario Ditaranto
    • Samuel Wiseman
    • Maja Kaszuba
    • Dariusz Mikielewicz
    2024

    This work focuses on the concept developed in the nCO2PP project, which aims to demonstrate a technology that allows to achieve negative CO2 emissions through Carbon Capture and Storage (CCS) applied to sewage sludge. A feedstock is first gasified, then the resulting syngas is burned in a semi-closed oxy-fuel gas turbine with pure oxygen and water, using the advantages of oxy-combustion, to ease the capture of CO2 in the resulting exhaust gases. High-temperature combustion later takes place in a dedicated wet combustion chamber before expansion in a turbine which produces electricity. Given that in Polish law sewage sludge is treated as biomass, a negative CO2 emission factor is achieved. Works in the project are performed both in experimental and design terms. The concept of transpiration cooling will be considered in terms of different methods. Additionally, previously unpublished computational flow dynamics (CFD) simulations related to transpiration cooling were compared with measurement and design analyses. Experimental efforts include a demonstration of water transpiration through a porous structure.

  • Network-assisted processing of advanced IoT applications: challenges and proof-of-concept application
    • Higinio Mora
    • Francisco A. Pujol
    • Tamai Ramírez
    • Antonio Jimeno-Morenilla
    • Julian Szymański
    2024 Full text Cluster Computing-The Journal of Networks Software Tools and Applications

    Recent advances in the area of the Internet of Things shows that devices are usually resource-constrained. To enable advanced applications on these devices, it is necessary to enhance their performance by leveraging external computing resources available in the network. This work presents a study of computational platforms to increase the performance of these devices based on the Mobile Cloud Computing (MCC) paradigm. The main contribution of this paper is to research the advantages and possibilities of architectures with multiple offloading options. To this end, a review of architectures that use a combination of the computing layers in the available infrastructure to perform this paradigm and outsource processing load is presented. In addition, a proof-of-concept application is introduced to demonstrate its realization along all the network layers. The results of the simulations confirm the high flexibility to offload numerous tasks using different layers and the ability to overcome unfavorable scenarios.

  • Neural network agents trained by declarative programming tutors
    • Jan Dobrosolski
    • Julian Szymański
    • Higinio Mora
    • Karol Draszawka
    2024

    This paper presents an experimental study on the development of a neural network-based agent, trained using data generated using declarative programming. The focus of the study is the application of various agents to solve the classic logic task – The Wumpus World. The paper evaluates the effectiveness of neural-based agents across different map configurations, offering a comparative analysis to underline the strengths and limitations of these approaches. We discuss the quantitative and qualitative aspects of these agents in scenarios that require generalization. For a concise comparison, we present the performance and resource utilization of different agents as follows: The Prolog- based agent showed a base task win rate of 61%, which dropped to 5% in a modified task setting, requiring 13KB of memory. The Q-Learning agent achieved a 2% win rate in the base task, with the modified task performance not applicable, and a memory requirement of 67KB. An agent based on a Convolutional Neural Network (CNN) recorded a 44% win rate on the base task and 32% on the modified task, consuming 134KB of memory. The Deep Q-Network (DQN) agent displayed a 56% win rate in the base task and 46% in the modified task, necessitating a substantial amount of memory, 284MB.

  • Neural network model of ship magnetic signature for different measurement depths
    • Kajetan Zielonacki
    • Jarosław Tarnawski
    2024

    This paper presents the development of a model of a corvette-type ship’s magnetic signature using an artificial neural network (ANN). The capabilities of ANNs to learn complex relationships between the vessel’s characteristics and the magnetic field at different depths are proposed as an alternative to a multi-dipole model. A training dataset, consisting of signatures prepared in finite element method (FEM) environment Simulia Opera was constructed. A feedforward neural network was developed through a comparative analysis of different activation functions available in MATLAB’s Deep Learning Toolbox and the grid search method. Verification was performed using the leave-one-out cross-validation method (LOOCV). The model proved to be highly effective in predicting the magnetic signature for the northward direction in any measurement depth, with prospects to expand it to estimate other directions.

  • New BB0108, BB0126, BB0298, BB0323, and BB0689 Chromosomally Encoded Recombinant Proteins of Borrelia burgdorferi sensu lato for Serodiagnosis of Lyme Disease
    • Weronika Grąźlewska
    • Tomasz Chmielewski
    • Beata Fiecek
    • Lucyna Holec-Gąsior
    2024 Pathogens

    Five chromosomally encoded proteins, BB0108, BB0126, BB0298, BB0323, and BB0689, from Borrelia burgdorferi sensu lato (s.l.), were obtained in three variants each, representing the most common genospecies found in Europe (Borrelia afzelii, Borrelia burgdorferi sensu stricto (s.s.), and Borrelia garinii). The reactivity of these recombinant proteins with the IgM and IgG antibodies present in human serum was assessed using Western blot (WB) and the ELISA. In IgG-WB, the proteins exhibited varying reactivity, peaking at approximately 40–50% for BB0108 and BB0689. However, none of these proteins were recognized by specific antibodies in the IgM-WB. The sensitivity of IgG-ELISA based on three variants of BB0108 and BB0323 ranged from 71% to 82% and from 62% to 72%, respectively. Conversely, the specificity of both tested proteins was consistently above 82%. Tests utilizing single variants of BB0323 did not yield any diagnostic value in detecting IgM antibodies. However, BB0108 demonstrated recognition by antibodies present in 52% to 63% of the tested sera. These antigens appear advantageous due to the consistent reactivity observed across their variants. This observation suggests that appropriate selection of antigens conserved within B. burgdorferi s.l. could offer a solution to the issue of variable sensitivity encountered in serodiagnostic tests across Europe.

  • New Biocompatible Ti-MOF@hydroxyapatite Composite Boosted with Gentamicin for Postoperative Infection Control
    • Weronika Bodylska
    • Adam Junka
    • Malwina Brożyna
    • Michał Bartmański
    • Renata Gadzała-Kopciuch
    • Anna Jaromin
    • Jorge A. R. Navarro
    • Anna Lukowiak
    • Marzena Fandzloch
    2024 ACS Biomaterials Science & Engineering

    The standard clinical management of osteomyelitis involves prolonged antibiotic therapy, which frequently necessitates the excision of infected tissues. However, the efficacy of such treatments is increasingly compromised by the rise of antibiotic-resistant pathogens, underscoring an urgent need for innovative approaches. This study introduces a novel composite material designed to offer dual functionality: robust antimicrobial activity and promotion of bone regeneration. The composite integrates biocompatible hydroxyapatite nanoparticles (HA) with a titanium(IV)–metal–organic framework, MIL-125(Ti)-NH2, impregnated with gentamicin (GM). The solvothermally synthesized MIL-125-NH2@HA composite demonstrates high cytocompatibility, as evidenced by assays using osteoblasts (U2-OS) and fibroblasts (L929), alongside an absence of hemolytic activity at concentrations of up to 1000 μg/mL. Importantly, the introduction of GM into the composite significantly amplifies its antibacterial efficacy against Staphylococcus aureus and Pseudomonas aeruginosa. Additionally, nanoindentation assessments reveal enhanced mechanical properties of the MIL-125-NH2@HA composite, indicating the superior elastic performance relative to unmodified HA. The findings of this research are poised to generate significant interest in the development of metal–organic framework (MOF)-based composites for antimicrobial implant applications, presenting a promising avenue for addressing the challenges posed by antibiotic resistance in bone infections.

  • New concept of drilling auger for displacement pile installation
    • Adam Krasiński
    2024 Full text

    In 2020, a new version of the screw displacement auger for pile installation in soil was developed and patented in Poland. It was named DPDT (Displacement Pile Drilling Tool). The general aim of its development was to reduce the soil resistances to the auger during screwing into the ground while maintaning a good load-bearing capacity for the screw displacement piles. The “DPDT-Auger” prototype was tested as a scaled-down model in the laboratory as well as in full-scale in the field. Its efficiency was compared with an ordinary SDP auger in two ways: by assessing soil resistances during screwing into the ground and by assessing the bearing capacity of completed piles. This paper presents the field tests and their results. Over 80 piles were tested in six test sites. Among them, 24 piles were instrumented and subjected to static load tests. The test results were generally positive and showed that the DPDT auger generates less torque than the SDP auger but requires more rotations and a slightly longer pile installation time. When it comes to the bearing capacity of the compression load, both DPDT and SDP piles showed similar characteristics.

  • New generation composite panels for military and civil applications: mechanical, thermal, fire, and acoustic properties
    • Adam Wawrzynowicz
    • Tomasz Wojtkiewicz
    2024 Inżynieria Bezpieczeństwa Obiektów Antropogenicznych

    The article presents selected results from a research programme on innovative composite panels featuring an insulating core and magnesium cement facings, optionally reinforced with additional steel facings. The scope of the research programme includes the assessment of the panels themselves, as well as the partitions constructed from them and entire buildings, including portable structures built in accordance with the requirements of the United States Army (UFC – Unified Facilities Criteria). Issues relating to structural performance, thermal efficiency, fire resistance, and acoustics were analysed.

  • New heterometallic Co/Zn, Ag/Co, and Ag/Zn imidazolates: structural characterization and catalytic activity in the oxidation of organic compounds
    • Mattia Lopresti
    • Łukasz Kurowski
    • Luca Palin
    • Marco Milanesio
    • Magdalena Siedzielnik
    • Karolina Gutmańska
    • Adrianna Dobrenko
    • Tomasz Klimczuk
    • Ewelina Pawelczyk
    • Anna Dołęga
    2024 Full text DALTON TRANSACTIONS

    Nanocrystalline powders of monometallic and bimetallic imidazolates of Co, Zn, and Ag were produced by a reaction carried out in water. The powders were characterized by powder X-ray diffraction and the crystal structures of new compounds Ag2ZnIm4 and Ag2CoIm4 (Im = imidazolate) were solved. Heterometallic Co/Zn imidazolates showed the standard ZIF-8 crystal structure while Ag/Zn and Ag/Co systems were isostructural with the copper analogs. The powders were further characterized by EDX, UV-Vis and FTIR ATR spectroscopy in solid state. The catalytic experiments indicated that out of the studied heterometallic compounds only Ag2Co(Im)4, exhibits some catalytic activity in the reaction of oxidation of 1-phenylethanol by tert-butylhydroperoxide at elevated temperature.

  • New skills for architects: 3D scanning for an immersive experience in architectural education
    • Szymon Kowalski
    • Jacek Lebiedź
    • Sandro Parinello
    • Francesca Picchio
    2024 Full text Global Journal of Engineering Education

    The authors of this article explore the integration of remote sensing techniques, specifically laser scanning and photogrammetry, as well as immersive visualisation via different methods applied to architectural design processes, and its potential impact on the professional development of future architects. The study demonstrates the value of extending the architectural design process into the interdisciplinary field of geomatics and computer science through mixed research methods, including interviews, hands-on activities, market observations and knowledge of technological advances. The study results suggest a growing demand for certain interdisciplinary skills among students, necessitating an expanded approach to architectural design education to take full advantage of technological advances. The observed new possibility of the emergence of new professional specialisations in architecture, such as digital inventory managers, highlights the need to adapt some educational pathways to meet the demands of the industry, especially in the context of architectural heritage. The implication of this approach is to recommend the integration of remote sensing techniques into architectural curricula to better prepare future architects for today’s ever-evolving practice.

  • New technologies for green hydrogen activation, storage, and transportation
    • Bráulio Barros
    • Natalia Łukasik
    • Joanna Kulesza
    • Jose Daniel da Silva Fonseca
    2024

    Developing new green hydrogen activation, storage, and transportation technologies is a highly complex and multidisciplinary endeavor. This challenge arises from integrating various scientific, engineering, and environmental considerations. Effective evaluation of green hydrogen technologies involves a holistic approach that considers not only the technical aspects but also economic, environmental, and social factors. These criteria help ensure that green hydrogen solutions contribute positively to sustainability and energy transition goals. This chapter aims to present the most recent and innovative approaches with respect to green hydrogen activation, storage, and transportation.

  • New trifunctional acrylic water-based paint with self-cleaning, biocidal and magnetic properties
    • Izabela Malinowska
    • Oliwia Paszkiewicz
    • Agata Markowska-Szczupak
    • Anna Zielińska-Jurek
    2024 Full text CERAMICS INTERNATIONAL

    In the present study, we report the synthesis and application of ZnFe2O4/SiO2-TiO2 nanocomposites with nonstoichiometric content of Fe to Zn used for the first time for the preparation of new generation trifunctional paints with self-cleaning, biocidal and magnetic properties. Currently, there are no compositions on the market for obtaining protective coatings in the form of paint, which simultaneously exhibit biocidal, magnetic and selfcleaning - photocatalytic properties. The effect of Zn:Fe content on the antimicrobial, magnetic and self-cleaning properties of obtained modified paints was investigated. Furthermore, the non-stoichiometric zinc ferrite in combination with TiO2 allowed to create of a surface that inhibits microorganisms’ growth. Self-cleaning properties were studied in the reaction of dye - neutral red degradation. The commercial white paint was not photocatalytic active. Paint modification with nanocomposites based on ZnO/ZnFe2O4 and TiO2 resulted in the effective degradation of natural red dye. The highest dye removal efficiency was observed for the sample containing ZnFe2O4/SiO2-TiO2 particles with a non-stoichiometric 1:2 (Fe: Zn) molar ratio. Trifunctional paints with photocatalytic, magnetic and biocidal properties are a novelty in building products. The composition can be applied to protective and decorative layers, giving magnetic, biocidal and self-cleaning properties.

  • News that Moves the Market: DSEX-News Dataset for Forecasting DSE Using BERT
    • Md. Nabil Rahman Khan
    • Md Rafiqul Islam
    • Cesar Sanin
    • Edward Szczerbicki
    2024

    Stock market is a complex and dynamic industry that has always presented challenges for stakeholders and investors due to its unpredictable nature. This unpredictability motivates the need for more accurate prediction models. Traditional prediction models have limitations in handling the dynamic nature of the stock market. Additionally, previous methods have used less relevant data, leading to suboptimal performance. This study proposes the use of Bidirectional Encoder Representations from Transformers (BERT), a pre-trained Large Language Model (LLM), to predict Dhaka Stock Exchange (DSE) market movements. We also introduce a new dataset designed specifically for this problem, capturing important characteristics and patterns that were missing in other datasets. We test our new dataset of headlines and stock market indexes on various machine learning techniques, including Decision Tree (DT), Logistic Regression (LR), K-Nearest Neighbors (KNN), Random Forest (RF), Linear Support Vector Machine (LSVM), Long Short-Term Memory (LSTM), Gated Recurrent Units (GRUs), Bidirectional Long Short-Term Memory (Bi-LSTM), BERT, Financial Bidirectional Encoder Representations from Transformers (FinBERT), and RoBERTa, which are compared to assess their predictive capabilities. Our proposed model achieves 99.83% accuracy on the training set and 99.78% accuracy on the test set, outperforming previous methods.

  • Niepewność dopasowania funkcji liniowej i logarytmicznej do punktów pomiarowych przy wyznaczaniu przewodności cieplnej materiałów
    • Andrzej Mowiec
    • Sławomira Janiak
    • Daria Mazurek-Rudnicka
    • Anna Golijanek-Jędrzejczyk
    • Dariusz Świsulski
    2024

    Wyznaczanie właściwości cieplnych różnych materiałów budowlanych stanowią dziedzinę wiedzy ważną do analizy problemów związanych z wymianą ciepła w technice. Dla cenienia wielkości przewodzenia ciepła bardzo istotne znaczenie mają badania pozwalające na doświadczalne wyznaczenie wartości współczynnika przewodności cieplnej  Znajomość tego współczynnika dla różnego rodzaju materiałów jest ważna w praktyce inżynierskiej, a także w badaniach eksperymentalnych. Najprostszą w realizacji metodą do wyznaczania przewodności cieplnej ciał stałych jak i cieczy jest metoda „gorącego drutu”. W publikacji zaprezentowano wyniki badań eksperymentalnych pomiaru temperatury oraz szacowania jej względnej niepewności pomiarowej przygotowanych próbek - elementu grzejnego w postaci odcinka izolowanego drutu oporowego o średnicy 0,2 mm na stanowisku badawczym.

  • Nitrogen oxides removal from hydrogen flue gas using corona discharge in marine boilers: Application perspective
    • Dominik Kreft
    • Konrad Marszałkowski
    • Karol Szczodrowski
    2024 Full text INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

    This paper focuses on the combustion of hydrogen in boilers, as it appears to be a more effective method than using fuel cells for heating purposes due to higher boiler efficiency. One of the main disadvantages of hydrogen combustion in air is NOx formation. Therefore, the authors decided to introduce corona discharge as an inno- vative technique to clean hydrogen flue gas by effectively reducing NOx levels. The method involves generating positive plasma at atmospheric pressure by applying up to a 23 kV voltage difference between rod and ring- shaped electrodes. Experimental studies have shown that corona discharge can significantly lower the concen- trations of NO and NOx in exhaust gases. The maximum DeNOx level was found to be 32.3%, while the plasma generator uses 17.5% of the power contained in burned hydrogen. The findings suggest that this technology holds potential for application in industrial hydrogen combustion systems, offering an environmentally friendly alternative to conventional NOx reduction methods.

  • Nitrogen-incorporated boron-doped diamond films for enhanced electrochemical supercapacitor performance
    • Shradha Suman
    • Mateusz Ficek
    • Kamatchi J Sankaran
    • Jacek Ryl
    • Benadict Rakesh
    • Mukul Gupta
    • Ramasamy Sakthivel
    • Robert Bogdanowicz
    2024 ENERGY

    The electrochemical (EC) supercapacitor, known for its rapid charging, reliability, and versatile applications, demands optimized electrode characteristics and an understanding of their electrochemical behaviour. Although boron-doped diamond (BDD) holds promise as a supercapacitor electrode, a crucial gap exists in comprehending its material behaviour under specific growth conditions. Here, nitrogen-incorporated BDD (N-BDD) films with different microstructures are investigated. The morphology of N-BDD films is varied by tuning the substrate temperature (Ts) from 400 °C to 850 °C during the growth process. The diamond films grown at lower Ts = 400 °C consist of faceted grains, and the grain sizes shrink as Ts is increased (550 °C and 700 °C). Interestingly, the films grown at 850 °C (N-BDD850°C) show nanowire-like morphology with enhanced electrical conductivity. The spectroscopy and microscopy results reveal the concurrence of sp3-diamond and sp2-graphitic phases in the nanowire morphology. The EC supercapacitor studies disclose that formation of nanowire-like morphology for N-BDD850°C increases the active surface area and electron transport properties; hence, higher current response and enhanced specific capacitance (0.09 F cm−2 at a current density of 1.53 mA cm−2) are observed. Lifecycle stability of 82% is observed after 5000 cycles indicating the efficient performance of N-BDD850°C films.

  • NMR-Based Structural Insight into DNA G-Quadruplex
    • Julia Pakuła
    2024

    Emerging as a promising area in anticancer research, noncanonical DNA structures such as G-quadruplexes are studied using NMR spectroscopy. NOESY spectra reveals crucial interactions between ligands and G-quadruplexes, helping to understand non-covalent binding mechanisms. This knowledge is essential for rational drug design targeting these structures.

  • Non-Adaptive Speed and Position Estimation of Doubly-Fed Induction Generator in Grid-Connected Operations
    • Marcin Morawiec
    • Krzysztof Blecharz
    2024 Full text IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS

    The nonadaptive speed and position estimation scheme for a doubly-fed induction generator (DFIG) is presented in this article. The observer structure is based on the extension of the mathematical model of DFIG to the introduced H vector. Based on the defined H vector, the nonadaptive position and speed estimation is proposed. The Lyapunov method is extended to the practical stability theorem to stabilize the structure. The classic stator field-oriented control to active and reactive power control is used in the sensorless control system. The performance of the proposed algorithm of the speed and position observer is validated by simulation and experimental results using the 2 kW generator. The comparison tests to the classical model reference adaptive system based observer are provided. Finally, the article contains a summary in which the non-adaptive speed estimation is discussed in context to the adaptive reconstruction of the rotor speed and position.

  • Noncentrosymmetric Triangular Magnet CaMnTeO6: Strong Quantum Fluctuations and Role of s0 versus s2 Electronic States in Competing Exchange Interactions
    • Xudong Huai
    • Emmanuel Acheampong
    • Erich Delles
    • Michał Winiarski
    • Maurice Sorolla II
    • Lila Nassar
    • Mingli Liang
    • Caleb Ramette
    • Huiwen Ji
    • Allen Scheie
    • Stuart Calder
    • Martin Mourigal
    • Thao Tran
    2024 Full text ADVANCED MATERIALS

    Noncentrosymmetric triangular magnets offer a unique platform for realizing strong quantum fluctuations. However, designing these quantum materials remains an open challenge attributable to a knowledge gap in the tunability of competing exchange interactions at the atomic level. Here, a new noncentrosymmetric triangular S = 3/2 magnet CaMnTeO6 is created based on careful chemical and physical considerations. The model material displays competing magnetic interactions and features nonlinear optical responses with the capability of generating coherent photons. The incommensurate magnetic ground state of CaMnTeO6 with an unusually large spin rotation angle of 127°(1) indicates that the anisotropic interlayer exchange is strong and competing with the isotropic interlayer Heisenberg interaction. The moment of 1.39(1) µB, extracted from low-temperature heat capacity and neutron diffraction measurements, is only 46% of the expected value of the static moment 3 µB. This reduction indicates the presence of strong quantum fluctuations in the half-integer spin S = 3/2 CaMnTeO6 magnet, which is rare. By comparing the spin-polarized band structure, chemical bonding, and physical properties of AMnTeO6 (A = Ca, Sr, Pb), how quantum-chemical interpretation can illuminate insights into the fundamentals of magnetic exchange interactions, providing a powerful tool for modulating spin dynamics with atomically precise control is demonstrated.

  • Nondestructive corrosion degradation assessment based on asymmetry of guided wave propagation field
    • Beata Zima
    • Emil Roch
    • Jochen Moll
    2024 ULTRASONICS

    The article presents the results of numerical and experimental investigation of guided wave propagation in steel plates subjected to corrosion degradation. The development of novel procedures allowing for the assessment of the corrosion degradation level is crucial in the effective diagnostics of offshore and ship structures that are especially subjected to aggressive environments. The study’s main aim is to investigate the influence of surface irregularities on wave propagation characteristics. The paper investigates wavefront asymmetry caused by the non-uniform thickness of damaged specimens. In the first step, the influence of thickness variability on the symmetry of the wave field has been investigated numerically. The corroded plates with variable degrees of degradation have been modeled using the random fields approach. The degree of degradation (DoD) varied from 0% to 40%. In the next step, the developed method was examined during experimental tests performed on specimens subjected to accelerated corrosion degradation. The experimental tests were conducted for intact and for corroded plates characterized by a DoD of 10%. It is demonstrated that the new approach based on wave field analysis can be used in structural state assessment.

  • Nondestructive global corrosion measurement using guided wavefield data
    • Beata Zima
    • Emil Roch
    2024 Full text MEASUREMENT

    Metallic structures often face degradation, and corrosion ranks among the most prevalent forms of deterioration. Accurate quantification of corrosion is crucial, especially for structures exposed to harsh environmental conditions, such as marine vessels and offshore installations. Because the traditional measurement methods based on scanning by ultrasonic gauge are time-consuming and provide only rough information on the thickness variability, there is a need to develop new robust and accurate diagnostics methods. This paper aims to investigate the corrosion monitoring of metal plates using guided wave propagation. Guided waves propagate within the entire volume of the specimen. If it is undamaged and isotropic, the velocity in all directions is the same, and the spreading wavefront takes a circular shape. The primary assumption presented in this paper is that the potential damage caused by corrosion leads to disturbance of this symmetry. The study shows Bilateral and Rotational Corrosion Symmetry Degree (BCSD and RCSD) functions, demonstrating a consistent decrease in symmetry values with increasing degree of degradation (DoD) caused by the corrosion process. The main aim of the study was to test the possibility of corrosion monitoring by using variable number of sensors comprising the transducer network. Also, the influence of the distance between the sensors affecting the size of the monitored area on the corrosion monitoring procedure was investigated. The paper contains the results of numerical and experimental campaigns conducted for corroded plates characterized by variable DoD and monitored using nine different transducers configurations. It is the first step in developing a novel measurement procedure specially designed for the ship and offshore industry. Therefore, because of the initial stage of the study, the last part of the paper discusses the limitations and drawbacks of the presented wave symmetry-based approach.

  • Non-invasive investigation of a submerged medieval harbour, a case study from Puck Lagoon
    • Łukasz Janowski
    • Andrzej Pydyn
    • Mateusz Popek
    • Paweł Tysiąc
    2024 Journal of Archaeological Science-Reports

    This study presents an innovative approach to underwater archaeological prospection using non-invasive methods of seabed exploration. The research focuses on the Puck medieval harbour, a cultural heritage site, and utilises acoustic and optical underwater remote-sensing technology. The primary objectives include optimising the use of Airborne Laser Bathymetry in underwater archaeology, enhancing the filtration process for mapping underwater sites, and utilising data from both multibeam echosounder and bathymetric LiDAR for detailed archaeological research. A systematic approach to data processing is advocated to maximise the value of collected data and inform subsequent investigations. The study demonstrates the high accuracy of bathymetric datasets from optical and acoustic sources, with an R-squared correlation coefficient of 0.9853. The application of these techniques is demonstrated, underscoring the compatibility and effective combination of these methods in underwater archaeological exploration. This research provides valuable insights and directions for future archaeological prospections based on active remote-sensing measurements.

  • Nonlinear free and forced vibrations of a dielectric elastomer-based microcantilever for atomic force microscopy
    • Amin Alibakhshi
    • Shahriar Dastjerdi
    • Mohammad Malikan
    • Victor Eremeev
    2024 Full text CONTINUUM MECHANICS AND THERMODYNAMICS

    The majority of atomic force microcode (AFM) probes work based on piezoelectric actuation. However, some undesirable phenomena such as creep and hysteresis may appear in the piezoelectric actuators that limit their applications. This paper proposes a novel AFM probe based on dielectric elastomer actuators (DEAs). The DE is modeled via the use of a hyperelastic Cosserat model. Size effects and geometric nonlinearity are included utilizing the modified couple stress theory and the von-Kármán strains. A non-contact interaction condition is adopted for AFM, which is taken into account via the van der Waals force. Governing equations are derived employing Hamilton’s principle, and a reduced model is obtained using an extended Galerkin scheme. The free vibration of the system is formulated when a static voltage is applied to the elastomer. The forced vibration is then formulated when the system is under a combination of static and dynamic voltages. The ordinary differential equations of the free and forced vibrations are numerically and analytically solved by the backward differentiation method and multiple time scales method, respectively. Results are presented in time histories, phase portraits, Poincaré maps, fast Fourier transforms, and frequency amplitude curves. Overall, the obtained information displays that the system undergoes quasiperiodic and periodic motions. Moreover, the resonant response of the DE-based AFM is softening-type.

  • NONSTRUCTURAL STIFFNESS ASSESSMENT IN INSTRUMENTED STEEL BUILDINGS
    • Tomasz Falborski
    • Amit Kanvinde
    2024

    Lateral stiffness of nonstructural components may significantly influence the initial stiffness of the entire structure and consequently alter its dynamic characteristics. While methods for simulating structural members are well-established, approaches for modeling nonstructural components that also participate in seismic response are notably less developed. In this paper a simplified, physically-intuitive approach for estimating the stiffness of nonstructural members based on vibration recordings of buildings is presented. The method comprises two components: (1) identifying the instants during the time history wherein components of interstory velocity are negligible, such that damping forces are zero, and (2) at these instants, using static analysis to estimate forces in the structural members by applying the recorded displacements to the entire structure, and the accelerations to all masses above the story of interest. The method derives from first-principles of dynamics and structural analysis, and is assessed against experimental data including shake table results on steel frames with nonstructural walls as well as quasi-static tests on the similar walls. The results are critically discussed in the context of their prospective applications in practical settings.

  • Normal stress distribution in built‑up cold‑formed column in relation to interconnecting bolt spacing
    • Patryk Deniziak
    • Elżbieta Urbańska-Galewska
    • Małgorzata Gordziej-Zagórowska
    2024 Full text Scientific Reports

    In order to increase a stiffness of cold-formed steel (CFS) elements it is practised to built-up the cross-section. In the analysed case, a main element is strengthened by adding extra chord in contact partially along the column. This additional chord acts as a longitudinal stiffener connected with the main section by series of bolts. Authors check whether rules applied over the years, for hot-rolled elements, can be indiscriminately used in the analysed CFS element. The aim of this study is to experimentally and computationally recognize the normal stress distribution in axially compressed CFS built-up column chords and to evaluate the element load-bearing capacity.

  • Novel benzenesulfonamide-aroylhydrazone conjugates as carbonic anhydrase inhibitors that induce MAPK/ERK-mediated cell cycle arrest and mitochondrial-associated apoptosis in MCF-7 breast cancer cells
    • Beata Żołnowska
    • Jarosław Sławiński
    • Jarosław Chojnacki
    • Andrea Petreni
    • Claudiu T. Supuran
    • Anna Kawiak
    2024 Full text BIOORGANIC & MEDICINAL CHEMISTRY

    A series of novel 4-alkylthio-2-chloro-5-[(2-arylmethylidene)hydrazinecarbonyl]benzenesulfonamide derivatives 3–22 were synthesized and evaluated for their inhibitory activity against human carbonic anhydrase isozymes hCA I, hCA II, hCA IX, and hCA XII. These compounds showed varying degrees of activity against the studied isoenzymes. However, the importance of substituent choice in designing potent carbonic anhydrase inhibitors is highlighted by the strong inhibition profiles of compounds 3 and 10 against hCA IX and the low average KI values for compounds 9 and 10 (134 nM and 77 nM, respectively). All the synthesized compounds were evaluated for their antiproliferative activity toward HeLa, HCT-116, and MCF-7 cell lines. Compounds 9 and 19 exhibited significant activity, particularly against the MCF-7 cell line (IC50 values of 4 μM and 6 μM, respectively). Notably, compound 9 demonstrated a high selectivity index (SI = 8.2) for MCF-7 cells. The antiproliferative effects of compounds 9 and 19 were linked to the induction of cell cycle arrest and apoptosis via the mitochondrial pathway and involved the activation of the MAPK/ERK signaling pathway. Inhibition of MAPK/ERK activity reduced the compounds’ ability to induce cell cycle arrest and apoptosis, indicating the critical role of this pathway. These findings suggest that compounds 9 and 19 are promising candidates for further development as specific and potent anticancer agents targeting the MAPK/ERK pathway.

  • Novel Complementary Multiple Concentric Split Ring Resonator for Reliable Characterization of Dielectric Substrates with High Sensitivity
    • Tanveer Haq Ul
    • Sławomir Kozieł
    2024 IEEE SENSORS JOURNAL

    Accurate characterization of dielectric substrates with high sensitivity remains an important challenge in a variety of industrial applications. This paper proposes an innovative strategy to address this challenge by developing and optimizing a unique Complementary Multiple Concentric Split Ring Resonator (CMC-SRR). The major goal is to propose a sensor design with increased sensitivity and reliability for dielectric characterization. The CMC-SRR sensor uses simple complementary SRR structures and a 50 Ω microstrip transmission line to resonate at 17 GHz. To obtain optimal performance, a sensitivity analysis is performed, taking into account the structure's shape, size, thickness, and permittivity (MUT). Fabrication specifics include the use of an LPKF ProtoLaser on a 0.51-mm-thick Rogers 5880 substrate, which allows for more efficient and cost-effective manufacturing. An inverse regression model is created to forecast the permittivity of unknown materials using measured resonance frequencies and sample thickness. Our research yielded significant results, including a relative sensitivity greater than eight percent and a maximum permittivity prediction error of less than seven percent. These findings outperform current state-of-the-art complementary resonator-based sensors described in the literature.

  • Novel Complementary Resonator for Dielectric Characterization of Substrates Based on Permittivity and Thickness
    • Tanveer Haq Ul
    • Sławomir Kozieł
    2024 IEEE SENSORS JOURNAL

    This paper presents a novel complementary resonator featuring high sensitivity, low fabrication cost, and improved performance. The proposed structure consists of a complementary concentric square and circular ring resonator (CCSCRR) with multiple splits to enhance the inductance of the resonator. The proposed CCSCRR is coupled to a microstrip transmission line with an impedance of fifty ohms to create a high-sensitivity sensor. The lumped element equivalent circuit is employed to explain the sensor's operating principle. The geometric parameters of the CCSCRR are optimized to resonate at 15 GHz and the optimized sensor is fabricated on 0.762 mm thick dielectric substrate AD250 (εr = 2.5 ± 0.04). Dielectric materials with relative permittivity ranging from 2.5 to 10.2 and thickness from 0.508 mm to 1.905 mm are employed to investigate the properties of the proposed sensor and to carry out its calibration. Based on the measured resonant frequencies of the CCSCRR sensor when loaded with different materials under test (MUTs), an inverse regression model is constructed to predict the permittivity of the MUT. Comparisons with state-of-the-art microwave devices show that the proposed design is superior in terms of sensitivity, dielectric characterization reliability, and the applicability scope in terms of the MUT’s thickness and permittivity.