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Repozytorium publikacji
Politechniki Gdańskiej

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  • MagMax: Leveraging Model Merging for Seamless Continual Learning
    • Daniel Marczak
    • Bartłomiej Twardowski
    • Tomasz Trzciński
    • Sebastian Cygert
    2024

    This paper introduces a continual learning approach named MagMax, which utilizes model merging to enable large pre-trained models to continuously learn from new data without forgetting previously acquired knowledge. Distinct from traditional continual learning methods that aim to reduce forgetting during task training, MagMax combines sequential fine-tuning with a maximum magnitude weight selection for effective knowledge integration across tasks. Our initial contribution is an extensive examination of model merging techniques, revealing that simple approaches like weight averaging and random weight selection surprisingly hold up well in various continual learning contexts. More importantly, we present MagMax, a novel model-merging strategy that enables continual learning of large pre-trained models for successive tasks. Our thorough evaluation demonstrates the superiority of MagMax in various scenarios, including class- and domain-incremental learning settings. The code is available on github.

  • Magnetic field mapping along a NV-rich nanodiamond-doped fiber
    • Adam Filipkowski
    • Mariusz Mrózek
    • Grzegorz Stępniewski
    • Mateusz Ficek
    • Dariusz Pysz
    • Wojciech Gawlik
    • Ryszard Buczyński
    • Adam M. Wojciechowski
    • Mariusz Klimczak
    2024 APPLIED PHYSICS LETTERS

    Integration of NV−-rich diamond with optical fibers enables guiding quantum information on the spin state of the NV− color center. Diamond-functionalized optical fiber sensors have been demonstrated with impressive sub-nanotesla magnetic field sensitivities over localized magnetic field sources, but their potential for distributed sensing remains unexplored. The volumetric incorporation of diamonds into the optical fiber core allows developing fibers sensitive to the magnetic field over their entire length. Theoretically, this makes distributed optical readout of small magnetic fields possible, but does not answer questions on the addressing of the spatial coordinate, i.e., the location of the field source, nor on the performance of a sensor where the NV− fluorescence is detected at one end, thereby integrating over color centers experiencing different field strength and microwave perturbation. Here, we demonstrate distributed magnetic field measurements using a step-index fiber with the optical core volumetrically functionalized with NV− diamonds. A microwave antenna on a translation stage is scanned along a 13 cm long section of a straight fiber. The NV− fluorescence is collected at the fiber's far end relative to the laser pump input end. Optically detected magnetic resonance spectra were recorded at the fiber output for every step of the antenna travel, revealing the magnetic field evolution along the fiber and indicating the magnetic field source location. The longitudinal distribution of the magnetic field along the fiber is detected with high accuracy. The simplicity of the demonstrated sensor would be useful for, e.g., magnetic-field mapping of photonics- and/or spintronics-based integrated circuits.

  • Magnetic hydrophobic deep eutectic solvents for orbital shaker-assisted dispersive liquid-liquid microextraction (MAGDES-OS-DLLME) - determination of nickel and copper in food and water samples by FAAS
    • Adil Elik
    • Hameed Haq
    • Grzegorz Boczkaj
    • Seçkin Fesliyan
    • Özlem Ablak
    • Nail Altunay
    2024 Pełny tekst JOURNAL OF FOOD COMPOSITION AND ANALYSIS

    In this work, a cheap and widely applicable dispersive liquid-liquid microextraction (DLLME) method was developed for the extraction of Ni(II) and Cu(II) from water and food samples and analysis using flame atomic absorption spectrometry. DLLME was assisted by orbital shaker, while ferrofluid as an extractant was based on deep eutectic solvent (DES). This ferrofluid was made of hydrophobic DES (hDES), composed of lauric acid and menthol (molar ratio 1:2), and toner powder@aliquat 336 magnetic particles. The extraction procedure does not require any heating or centrifugation. The method limits of detection value were 0.15 µg L−1 and 0.03 µg L−1 for Ni(II) and Cu(II) respectively along with wide linearity range (0.4–250 µg L−1). The validation of the method was performed using certified reference materials (CRMs). The studies revealed excellent accuracy between results obtained by the developed method and expected values for all CRMs. The relative recoveries of Ni(II) and Cu(II) ions ranged from 92.8% to 98.6%. The developed method was further used for the determination of Ni(II) and Cu(II) in real water and food samples and provided quantitative recoveries.

  • Magnetic Porous Material Derived from Ni-MOF for the Removal of Tetracycline from Aqueous Solution
    • Yuhui Xue
    • Jingjing Wang
    • Mengjie Wang
    • Jiang Li
    • Kefu Wang
    • Afaq Hassan
    • Changyan Guo
    • Jide Wang
    2024 ACS Applied Nano Materials

    The efficient removal of antibiotic residues from aqueous solution is very important for water security. Studies have found that adsorption is widely used for the removal of antibiotics due to its cost-effectiveness, low energy consumption, simplicity of operation, and environmental friendliness. In this study, a novel magnetic porous carbon adsorbent (Ni-MPC-400) with a high adsorption capacity and saturation magnetization was synthesized via direct carbonization of Ni-MOF at 400 °C pyrolysis temperature and used to efficiently remove tetracycline from an aqueous solution. Adsorption experiments showed that Ni-MPC-400 exhibited excellent tetracycline adsorption capacity (441.51 mg·g–1) from the aqueous solution. Possible adsorption mechanisms were proposed through characterization and analysis. The adsorption mechanisms mainly involved π–π interactions, hydrogen bonding, metal–organic complexation, and pore filling effects. In addition, Ni-MPC-400 showed rapid and sufficient adsorption at a low concentration of tetracycline (5 mg·L–1) and good adsorption performance over a wide pH range. In addition, the material has been tested to have good immunity to interference and regenerative capacity, demonstrating a potential application in the removal of tetracycline contaminants from aqueous solutions.

  • Magnetic superhydrophobic melamine sponges for crude oil removal from water
    • Patrycja Makoś-Chełstowska
    • Edyta Słupek
    • Aleksandra Mielewczyk-Gryń
    • Tomasz Klimczuk
    2024 CHEMOSPHERE

    This paper proposes the preparation of a new sorbent material based on melamine sponges (MS) with superhydrophobic, superoleophilic, and magnetic properties. This study involved impregnating the surface of commercially available MS with eco-friendly deep eutectic solvents (DES) and Fe3O4 nanoparticles. The DES selection was based on the screening of 105 eutectic mixtures using COSMO-RS modeling. Other parameters affecting the efficiency and selectivity of oil removal from water were optimized using the Box-Bhenken model. Menthol:Thymol (1:1)@Fe3O4-MS exhibited the highest sorption capacity for real crude oils (101.7–127.3 g/g). This new sponge demonstrated paramagnetic behavior (31.06 emu/g), superhydrophobicity (151°), superoleophobicity (0°), low density (15.6 mg/cm3), high porosity (99 %), and excellent mechanical stability. Furthermore, it allows multiple regeneration processes without losing its sorption capacity. Based on these benefits, Menthol:Thymol (1:1)@Fe3O4-MS shows promise as an efficient, cost-effective, and eco-friendly substitute for the existing sorbents.

  • Magnetyczne i elektromagnetyczne uchwyty obróbkowe - konstrukcja i rozwój
    • Adam Barylski
    2024 Kwartalnik Naukowo-Techniczny "Obróbka Metalu"

    Przedstawiono współczesne rozwiązania konstrukcyjne obróbkowych uchwytów magnetycznych i elektromagnetycznych. Podano przykłady zastosowania w operacjach obróbki wiórowej i ściernej oraz w różnorodnych procesach spawania. Omówiono ważniejsze zalecenia technologiczne oraz ograniczenia praktyczne.

  • MAKSYMALIZACJA WYTRZYMAŁOŚCI NA OBCIĄŻENIE OSIOWE BUTELEK PET Z PUNKTU WIDZENIA ICH TRANSPORTU
    • Waldemar Karaszewski
    • Rafał Gawarkiewicz
    • Paweł Wawrzyniak
    2024 Przemysł Chemiczny

    Przewóz opakowań PET na paletach obarczony jest coraz większym ryzykiem ich odkształcania się pod wpływem obciążenia masą kolejnych warstw butelek. Doświadczenie pokazuje, że w transporcie opakowań PET o dużej objętości (5-6 litrów) decydującym elementem jest wytrzymałość osiowa górnej części opakowania. W artykule omówiono wybrane wyniki z szeroko przeprowadzonych analiz numerycznych wykonanych w celu określenia kształtu górnej części butelki PET o możliwie największej wytrzymałości osiowej w warunkach obciążeń podczas transportu. Przyjęty model numeryczny zweryfikowano doświadczalnie.

  • Management of Complex Root Fractures in Young Patients—Case Series and a Literature Review
    • Hanna Sobczak-Zagalska
    • Dorota Ogonowska-Paul
    • Michał Bartmański
    • Paulina Adamska
    2024 Journal of Clinical Medicine

    Root fractures are defined as injuries involving dentine, cementum, and the pulp. They are rare, and they account for 0.5–7% of the dental injuries in the permanent teeth. Root fractures may be the result of direct trauma to the teeth or indirect trauma to the oral cavity. Their incidence is highest in the group of adolescent patients aged 11 to 20 years. The purpose of the paper is to review the literature supported by a case series with three different types of root fractures with various healing patterns, though all with successful long-term treatment outcomes. Case series: All presented patients were boys aged 10 to 11 years. Root fractures occurred as a result of direct impact with the teeth by an object. Only one boy had his root-fractured teeth endodontically treated. However, one of the teeth was misdiagnosed with pulp necrosis, and the other became non-vital after additional trauma. Conclusions: Root fractures in young patients have good healing potential. Appropriate and early diagnostic and therapeutic procedures for treating root-fractured teeth are necessary to achieve favorable healing and a good long-term prognosis. Regardless of the pattern of healing of fractured roots and the treatment provided, patients require long-term follow-up and the need to plan a management strategy in case complications occur. Failure of the healing of fractured root is a worst-case scenario, especially in patients of developmental age. In such cases, the primary goal of treatment is to preserve the alveolar ridge until growth is complete.

  • Management of energy renovation for traditional rural residential houses
    • Magdalena Szarejko
    2024 Budownictwo i Architektura

    Renowacja energetyczna ma na celu zmniejszenie energii zużywanej przez budynek poprzez poprawę właściwości cieplnych przegród budowlanych oraz usprawnienie efektywności systemów instalacyjnych. Jest to istotny element w osiąganiu celów klimatycznych zdefiniowanych przez społeczność międzynarodową. Renowacja zabudowy o wartości kulturowej wiąże się z koniecznością zachowania cech architektonicz- nych, decydujących o jej rozpoznawalności, co istotnie komplikuje i ogranicza dobór metod i środków. W Polsce proces ten polega najczęściej na niepełnej termomodernizacji uwzględniającej wybrane elementy budynku wraz z wymianą źródła ciepła. Efektem jest jedynie niewielkie zmniejszenie strat energii oraz znacząca utrata walorów architektonicznych. Przedmiotem badania jest ocena możliwości zastosowania kompleksowego zarządza- nia renowacją energetyczną na poziomie lokalnym, w celu poprawy ochrony i zachowania cech tradycyjnej ceglanej zabudowy, stanowiącej wyróżnik architektoniczny wsi pomor- skiej. Zaproponowano model zintegrowanego systemu zarządzania renowacją energetyczną budynku. Sięgnięto po funkcjonujące w Europie wzory rozwiązań, które przeanalizowano pod kątem możliwości dostosowania do krajowej specyfiki. Wskazano na złożoność problemu. Artykuł rekomenduje uwzględnienie całego cyklu życiowego budynku w procesie zarządzania renowacją: od wniosków z badania zastosowanych rozwiązań planistycznych, projektowych i wykonawczych po kontrolę efektów energetycznych w trakcie eksploatacji

  • Management of ground tire rubber waste by incorporation into polyurethane-based composite foams
    • Aleksander Hejna
    • Paulina Kosmela
    • Adam Olszewski
    • Łukasz Zedler
    • Krzysztof Formela
    • Katarzyna Skórczewska
    • Adam Piasecki
    • Mariusz Marć
    • Roman Barczewski
    • Mateusz Barczewski
    2024 Pełny tekst ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH

    Rapid economic growth implicated the developing multiple industry sectors, including the automotive branch, increasing waste generation since recycling and utilization methods have not been established simultaneously. A very severe threat is the generation of enormous amounts of post-consumer tires considered burdensome waste, e.g., due to the substantial emissions of volatile organic compounds (VOCs). Therefore, it is essential to develop novel, environmentally friendly methods for their utilization, which would hinder their environmental impacts. One of the most promising approaches is shredding, resulting in the generation of ground tire rubber (GTR), which can be introduced into polymeric materials as filler. The presented work is related to the thermomechanical treatment of GTR in a twin-screw extruder with zinc borate, whose incorporation is aimed to enhance shear forces within the extruder barrel. Modified GTR was introduced into flexible polyurethane (PU) foams, and the impact of modification parameters on the cellular structure, static and dynamic mechanical performance, thermal stability, as well as thermal insulation, and acoustic properties were investigated. Emissions of VOCs from applied fillers and prepared composites were monitored and evaluated. Depending on the treatment parameters, beneficial changes in foams’ cellular structure were noted, which enhanced their thermal insulation performance, mechanical strength, and thermal stability. It was proven that the proposed method of GTR thermomechanical treatment assisted by zinc borate particles might benefit the performance of flexible PU foamed composites and hinder VOCs emissions, which could broaden the application range of GTR and provide novel ways for its efficient utilization

  • Managing and funding the innovative path: a close look at the SimLE scientific club at Gdańsk University of Technology, Poland
    • Wiktor Sieklicki
    • Maciej Zawadzki
    2024 Global Journal of Engineering Education

    This article presents a case study of the simply learn experience (SimLE) scientific club at Gdańsk University of Technology (Gdańsk Tech), Gdańsk, Poland, showcasing an effective model for blending theoretical knowledge with practical engineering applications. This student-led organisation aims to develop soft skills and handson experience through project work, participation in international contests and conferences. This study examines the funding mechanisms, educational impacts and management strategies of competitive achievements within SimLE. The results show that the level of financial support moderately affects the output of academic publications. However, this support is crucial for enhancing international visibility and facilitating participation in academic conferences. Also, it directly correlates with students’ engagement. Importantly, the research reveals that variations in scientific output are more closely associated with the composition of teams and management approaches rather than the extent of financial backing

  • Managing knowledge in a tourism crisis: case study from Poland
    • Ewa Stolarek-Muszyńska
    • Małgorzata Zięba
    • Ettore Bolisani
    • Enrico Scarso
    2024 Pełny tekst

    Purpose: This study deals with a tourism organisation from Poland, which experienced not only the COVID-19 pandemic, but also the close war situation in Ukraine which caused a significant decrease in tourist traffic and revenues. Since, based on the literature, knowledge management can be useful for crisis management, this study aims to explore the role and usefulness of KM during crisis situations in tourism. Methodology: Qualitative in-depth analysis was conducted by using data collected via semi-structured interview with the CEO of a local tourism organisation in Poland. The research output is presented in the form of a single case study with that organisation as the unit of analysis. Findings: The case highlighted that: a) a crisis may not be the most appropriate time for the implementation of KM from the scratch in an organisation; b) having some minimal KM experience can be essential for a more structured and complex KM approach; c) organisations may benefit from lessons learned during the crisis to get insights for developing KM. These findings suggest that practitioners and policymakers facilitate KM awareness among tourism organisations to enhance resilience in coping with future crises. Research limitations: This is a single case study and thus it cannot be easily generalised or provide a comprehensive overview of the whole sector. It is also a case study from a single country, affected by two serious crises which limits the applicability of the results to other countries. Practical implications: The study provides useful insights for practitioners in tourism organisations aspiring to improve internal processes of knowledge management and thus mitigating the future tourism crises. Originality/value: This paper contributes to the body of knowledge in terms of the role and relevance of KM during the tourism crisis. It provides food for thought for researchers investigating the knowledge and crisis management processes within the tourism industry.

  • Mangiferin: A comprehensive review on its extraction, purification and uses in food systems
    • Roberto Castro Munoz
    • René Cabezas
    • Maksymilian Plata Gryl
    2024 ADVANCES IN COLLOID AND INTERFACE SCIENCE

    With the target of fabricating healthier products, food manufacturing companies look for natural-based nutraceuticals that can potentially improve the physicochemical properties of food systems while being nutritive to the consumer and providing additional health benefits (biological activities). In this regard, Mangiferin joins all these requirements as a potential nutraceutical, which is typically contained in Mangifera indica products and its by-products. Unfortunately, knowing the complex chemical composition of Mango and its by-products, the extraction and purification of Mangiferin remains a challenge. Therefore, this comprehensive review revises the main strategies proposed by scientists for the extraction and purification of Mangiferin. Importantly, this review identifies that there is no report reviewing and criticizing the literature in this field so far. Our attention has been targeted on the timely findings on the primary extraction techniques and the relevant insights into isolation and purification. Our discussion has emphasized the advantages and limitations of the proposed strategies, including solvents, extracting conditions and key interactions with the target xanthone. Additionally, we report the current research gaps in the field after analyzing the literature, as well as some examples of functional food products containing Mangiferin.

  • Marine polymers in tissue bioprinting: Current achievements and challenges
    • Adrianna Banach-Kopeć
    • Szymon Mania
    • Robert Tylingo
    2024 Pełny tekst REVIEWS ON ADVANCED MATERIALS SCIENCE

    Bioprinting has a critical role in tissue engineering, allowing the creation of sophisticated cellular scaffolds with high resolution, shape fidelity, and cell viability. Achieving these parameters remains a challenge, necessitating bioinks that are biocompatible, printable, and biodegradable. This review highlights the potential of marine-derived polymers and crosslinking techniques including mammalian collagen and gelatin along with their marine equivalents. While denaturation temperatures vary based on origin, warm-water fish collagen and gelatin emerge as promising solutions. Building on the applications of mammalian collagen and gelatin, this study investigates their marine counterparts. Diverse research groups present different perspectives on printability and cell survival. Despite advances, current scaffolds are limited in size and layers, making applications such as extensive skin burn treatment or tissue regeneration difficult. The authors argue for the development of bioprinting, which includes spherical and adaptive printing. In adaptive printing, layers differentiate and propagate sequentially to overcome the challenges of multilayer printing and provide optimal conditions for the growth of deeply embedded cells. Moving the boundaries of bioprinting, future prospects include transformative applications in regenerative medicine.

  • Maritime traffic situation awareness analysis via high-fidelity ship imaging trajectory
    • Xinqiang Chen
    • Jinbiao Zheng
    • Chaofeng Li
    • Bing Wu
    • Huafeng Wu
    • Jakub Montewka
    2024 MULTIMEDIA TOOLS AND APPLICATIONS

    Situation awareness provides crucial yet instant information to maritime traffic participants, and significant attentions are paid to implement traffic situation awareness task via various maritime data source (e.g., automatic identification system, maritime surveillance video, radar, etc.). The study aims to analyze traffic situation with the support of ship imaging trajectory. First, we employ the dark channel prior model to remove fog in maritime videos to obtain high-resolution ship images (i.e., fog-free maritime images). Second, we track ships in each maritime image with the scale adaptive kernel correlation filter (SAMF), and thus obtain raw ship imaging trajectories. Third, we cleanse abnormal ship trajectory samples via curve-fitting and down sampling method, and thus further maritime traffic situation analysis is implemented. We analyze maritime traffic situation in three typical videos (i.e., three typical maritime traffic scenarios), and experimental results suggested that the proposed framework can extract high-resolution ship imaging trajectory for fulfilling the task of accurate maritime traffic situation awareness.

  • MARS - BAZA. warsztaty pozaziemskiej architektury ekstremalnej. Warsztaty w ramach Bałtyckiego Festiwalu Nauki
    • Aleksandra Karpińska
    • Agnieszka Kurkowska
    • Marta Koperska-Kośmicka
    • Marcin Kulesza
    2024

    Jak przetrwać w różnych warunkach? Czego potrzebujemy, by przeżyć, a czego, by żyć wygodnie? Poszukamy odpowiedzi na te pytania, by stanąć przed nie lada misją: wspólnie podejmiemy się największego wyzwania przyszłości - zbudujemy bazę na Marsie! Budowa schronienia, bazy, domu - troska o zaspokojenie podstawowych potrzeb towarzyszy nam od zawsze, a budowanie jest jednym z pierwszych trwałych działań ludzi, pomagającym spełnić nasze potrzeby bytowe. Z innymi wyzwaniami stykamy się jednak, kiedy planujemy budować dom, a innymi, kiedy spotykamy się z warunkami ekstremalnymi, kiedy standardowe rozwiązania nie mają zastosowania. Lekcja myślenia o projektowaniu w warunkach ekstremalnych to wstęp do zadania praktycznego w nurcie dizajnu spekulatywnego: uczestnicy będą projektować i budować w skali 1:1 model własnej bazy na Marsie.

  • Materiałowe aspekty budowy narzędzi docierarek tarczowych do płaszczyzn
    • Adam Barylski
    2024 Inżynieria Materiałowa

    Przedstawiono problematykę doboru materiałów na narzędzia w operacjach docierania i szlifowania powierzchni na obrabiarkach tarczowych. Scharakteryzowano stosowane materiały na tego typu narzędzia oraz wybrane konstrukcje tarcz do obróbki elementów płaskich i płasko-równoległych. Wskazano na korzystne zastosowanie żeliw sferoidalnych w aspekcie aktywizacji powierzchni czynnej docieraków ścierniwem. Przedstawiono analizę modelową aktywizacji docieraków z niestopowego żeliwa sferoidalnego. Omówiono opracowane konstrukcje narzędzi ścierno-metalowych oraz porównano docieranie luźnym ścierniwem i szlifowanie ściernicami segmentowymi na docierarkach tarczowych.

  • MATRYCA. NANO – qual-IA.
    • Krzysztof Wróblewski
    2024

    Wystawa podejmie problem konstytuowania i określania stopnia „zrozumiałości” wypowiedzi artystycznych (w jej różnych formach). Punktem odniesienia dla powstałych prac są pojęcia matrycy społecznej oraz treści percepcyjnej. >>Jaka może być najmniejsza porcja informacji? Jaka może być najmniejsza porcja doświadczenia? << Nikt nie wie do czego funkcjonalnie służy świadomość. Super inteligencja umożliwia szybkie przetwarzanie danych (jak w AI), które jednak potrafi odbywać się bez udziału świadomości. Matryca (łac. mater– matka, ang - matrix) jest to ogólne określenie formy do wykonywania kopii. W biologii molekularnej „matryca” to fragment DNA, na którym odbywa się amplifikacja - proces, podczas którego dochodzi do zwielokrotniania liczby lub zwiększania ilości. Najczęściej termin ten jest stosowany w odniesieniu do powielania (namnażania) DNA w genomie. Zachodzi pod wpływem różnych hormonów, które regulują funkcjonowanie narządów organizmu. Można obserwować zwrotne oddziaływanie pomiędzy wydzielaniem hormonów a stanami psychicznymi wywołanymi w związku z doświadczaniem silnych emocji i uczuć. Odbiorczość (receptywność) i intencjonalność (ukierunkowane działanie) są ważnym elementem fenomenu qualiów - jednostek percepcyjnych właściwych człowiekowi. Rozważa się nawet możliwość, że ludzki umysł może łamać funkcję falową, tworzyć kolaps kwantowy i tym samym wpływać na „matrycę” podłoża świadomości (tego nie potrafi obliczeniowa sztuczna inteligencja). Brać jednak trzeba też pod uwagę ograniczone zdolności poznawcze człowieka - błędy poznawcze, przekonania fałszywe, idealizacje, uproszczenia, luki pamięciowe i w postrzeganiu. Jak owe braki miałyby wpływać na proces łamania funkcji kwantowej? Jak bardzo kreowana w umyśle utopia wpływać może na treści przeżycia a tym samym kształtować „ukierunkowaną” postawę i określać kontekst sensu? Qualia są dla percepcji niczym układ hormonalny w organizmie. Działaniowy i performatywny status przeżyć może w konsekwencji wpływać na charakter zaangażowania jednostki w społeczną matrycę wspólnotowego uczestnictwa. Czy owo uczestnictwo jest jednak wystarczające jako warunek zrozumiałości prezentowanej treści, choćby w wypowiedzi artystycznej? Koncepcja: Marek Rogulski TNS / ICS

  • Maximizing Bio-Hydrogen and Energy Yields Obtained in a Self-Fermented Anaerobic Bioreactor by Screening of Different Sewage Sludge Pretreatment Methods
    • Alaa A. El-kebeer
    • Usama F. Mahmoud
    • Sayed Ismail
    • Abu Abbas E. Jalal
    • Przemysław Kowal
    • Hussein Al-Hazmi
    • Gamal K. Hassan
    2024 Pełny tekst Processes

    Egypt faces significant challenges in managing its sewage sludge generated in large quantities from wastewater treatment plants. This study investigates the feasibility of utilizing sewage sludge as a renewable resource for hydrogen production through anaerobic digestion at the 100 L bioreactor level. Hydrogen is considered a promising alternative energy source due to its high energy content and environmental benefits. To optimize the microbial degradation process and maximize hydrogen production from sewage sludge, a specialized pretreatment is necessary. Various pretreatment methods have been applied to the sewage sludge, individually and in combination, to study the bio-hydrogen production from sewage sludge. The four methods of treatment were studied in batch assays as a pilot scale. Thermal pretreatment of sewage sludge significantly increases bio-hydrogen production yield compared to other sewage sludge pretreatment methods, producing the highest H2 yield (6.48 LH2/g VS). In general, the hydrogen yield of any type of pretreated inoculum was significantly higher than the untreated inoculum. At the same time, alkaline pretreatment improved the hydrogen yield (1.04 LH2/g VS) more than acid pretreatment (0.74 LH2/g VS), while the hydrogen yield for the combination of pretreatments (shock alkali pretreatment) was higher than both (1.73 LH2/g VS), On the other hand, untreated sewage sludge (control) had almost no hydrogen yield (0.03 LH2/g VS). The self-fermented anaerobic bioreactor improved sewage sludge utilization, increased bioenergy yields, and seems to be promising for treating complex wastes at this scale.

  • Maximizing SDN resilience to node‐targeted attacks through joint optimization of the primary and backup controllers placements
    • Michał Pióro
    • Mariusz Mycek
    • Artur Tomaszewski
    • Amaro de Sousa
    2024 Pełny tekst NETWORKS

    In Software Defined Networks (SDN) packet data switches are configured by a limited number of SDN controllers, which respond to queries for packet forwarding decisions from the switches. To enable optimal control of switches in real time the placement of controllers at network nodes must guarantee that the controller-to-controller and switch-to-controller communications delays are bounded. Apart from the primary controllers that control the switches in the nominal state, separate backup controllers can be introduced that take over when the primary controllers are unavailable, and whose delay bounds are relaxed. In this paper we present optimization models to jointly optimize the placement of primary and backup controllers in long-distance SDN networks, aimed at maximizing the network's resilience to node-targeted attacks. Applying the models to two well-known network topologies and running a broad numerical study we show that, when compared with the standard approach of using only primary controllers, the use of backup controllers provides significant resilience gains, in particular in case of strict delay bounds.

  • Measurement Performance Verification of Asynchronous Method for Simultaneous Estimation of Object Position and Orientation
    • Jarosław Sadowski
    • Olga Błaszkiewicz
    • Krzysztof Cwalina
    • Alicja Olejniczak
    • Piotr Rajchowski
    • Jacek Stefański
    2024

    The paper describes the results of a measurement verification of the effectiveness of an asynchronous method of locating an object on a plane using localization signals sent simultaneously from two transmitters placed on that object at a known distance from each other. The advantage of proposed solution is ability to estimate position of mobile object by set of reference receivers that can work asynchronously, which simplifies the construction of reference nodes.

  • Measuring Tilt with an IMU Using the Taylor Algorithm
    • Jerzy Demkowicz
    2024 Remote Sensing

    This article addresses the important problem of tilt measurement and stabilization. This is particularly important in the case of drone stabilization and navigation in underwater environments, multibeam sonar mapping, aerial photogrammetry in densely urbanized areas, etc. The tilt measurement process involves the fusion of information from at least two different sensors. Inertial sensors (IMUs) are unique in this context because they are both autonomous and passive at the same time and are therefore very attractive. Their calibration and systematic errors or bias are known problems, briefly discussed in the article due to their importance, and are relatively simple to solve. However, problems related to the accumulation of these errors over time and their autonomous and dynamic correction remain. This article proposes a solution to the problem of IMU tilt calibration, i.e., the pitch and roll and the accelerometer bias correction in dynamic conditions, and presents the process of calculating these parameters based on combined accelerometer and gyroscope records using a new approach based on measuring increments or differences in tilt measurement. Verification was performed by simulation under typical conditions and for many different inertial units, i.e., IMU devices, which brings the proposed method closer to the real application context. The article also addresses, to some extent, the issue of navigation, especially in the context of dead reckoning.

  • Mechanical Properties of 3D Printed Parts and Their Injection Molded Alternatives Subjected to Environmental Aging
    • Angela Jadwiga Andrzejewska
    2024 3D Printing and Additive Manufacturing

    Additive manufacturing is the technology used in medical, industrial, or lifestyle applications. The scientific literature include works reporting various manufacturing parameters’ influence on changes in additive manufacturing components’ mechanical behavior, especially with fused filament fabrication (FFF). The changes in mechanical strength and toughness of FFF compared to injection molding parts were studied. In the study, the FFF and injection molded parts were aged in buffered saline solution in temperature of 37C. The results show that by differentiating the orientation of the fibers during fabricating, it is possible to reach strength values similar to injection molded parts. Therefore, it was reported that the mechanical strength and toughness changed significantly after aging, and the FFF components lost strength more quickly than their injected alternatives. The research results can be useful during the fabrication of mechanically stable and biodegradable components, which can be more easily recycled than their injected alternatives when used with warmer temperatures and humidity. This article completes the present state of the art on the problem of environmental aging of parts produced from biodegradable materials. Especially, the research was related to the multilayer laminate structure.

  • Mechanical Properties of Additively Manufactured Polymeric Materials—PLA and PETG—For Biomechanical Applications
    • Rui F. Martins
    • Ricardo Branco
    • Miguel Martins
    • Wojciech Macek
    • Zbigniew Marciniak
    • Rui Silva
    • Daniela Trindade
    • Carla Moura
    • Margarida Franco
    • Cândida Malça
    2024 Pełny tekst Polymers

    The study presented herein concerns the mechanical properties of two common polymers for potential biomedical applications, PLA and PETG, processed through fused filament fabrication (FFF)—Material Extrusion (ME). For the uniaxial tension tests carried out, two printing orientations—XY (Horizontal, H) and YZ (Vertical, V)—were considered according to the general principles for part positioning, coordinates, and orientation typically used in additive manufacturing (AM). In addition, six specimens were tested for each printing orientation and material, providing insights into mechanical properties such as Tensile Strength, Young’s Modulus, and Ultimate Strain, suggesting the materials’ potential for biomedical applications. The experimental results were then compared with correspondent mechanical properties obtained from the literature for other polymers like ASA, PC, PP, ULTEM 9085, Copolyester, and Nylon. Thereafter, fatigue resistance curves (S-N curves) for PLA and PETG, printed along 45°, were determined at room temperature for a load ratio, R, of 0.2. Scanning electron microscope observations revealed fibre arrangements, compression/adhesion between layers, and fracture zones, shedding light on the failure mechanisms involved in the fatigue crack propagation of such materials and giving design reference values for future applications. In addition, fractographic analyses of the fatigue fracture surfaces were carried out, as well as X-ray Computed Tomography (XCT) and Thermogravimetric (TGA)/Differential Scanning Calorimetric (DSC) tests.

  • Mechanical response of human thoracic spine ligaments under quasi-static loading: An experimental study
    • Radosław Wolny
    • Tomasz Wiczenbach
    • Angela Andrzejewska
    • Jan Henryk Spodnik
    2024 Journal of the Mechanical Behavior of Biomedical Materials

    Purpose This study aimed to investigate the geometrical and mechanical properties of human thoracic spine ligaments subjected to uniaxial quasi-static tensile test. Methods Four human thoracic spines, obtained through a body donation program, were utilized for the study. The anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), capsular ligament (CL), ligamenta flava (LF), and the interspinous ligament and supraspinous ligament complex (ISL + SSL), were investigated. The samples underwent specimen preparation, including dissection, cleaning, and reinforcement, before being immersed in epoxy resin. Uniaxial tensile tests were performed using a custom-designed mechanical testing machine equipped with an environmental chamber (T = 36.6 °C; humidity 95%). Then, the obtained tensile curves were averaged preserving the characteristic regions of typical ligaments response. Results Geometrical and mechanical properties, such as initial length and width, failure load, and failure elongation, were measured. Analysis of variance (ANOVA) revealed significant differences among the ligaments for all investigated parameters. Pairwise comparisons using Tukey's post-hoc test indicated differences in initial length and width. ALL and PLL exhibited higher failure forces compared to CL and LF. ALL and ISL + SSL demonstrated biggest failure elongation. Comparisons with other studies showed variations in initial length, failure force, and failure elongation across different ligaments. The subsystem (Th1 – Th6 and Th7 – Th12) analysis revealed increases in initial length, width, failure force, and elongation for certain ligaments. Conclusions Variations of both the geometric and mechanical properties of the ligaments were noticed, highlighting their unique characteristics and response to tensile force. Presented results extend very limited experimental data base of thoracic spine ligaments existing in the literature. The obtained geometrical and mechanical properties can help in the development of more precise human body models (HBMs).

  • Mechanisms of Li deposition on graphite anodes: surface coverage and cluster growth
    • Arihant Bhandari
    • Jacek Dziedzic
    • John R. Owen
    • Denis Kramer
    • Chris-Kriton Skylaris
    2024 Pełny tekst Journal of Materials Chemistry A

    Li plating on the anode is a side reaction in Li-ion batteries which competes with Li intercalation and leads to loss of capacity. Growth of Li clusters into dendrites is a potential safety hazard for batteries which can lead to internal short-circuit and fires. We consider two possibilities of Li deposition on the surface of graphite anode: deposition of Li+ ions uniformly on the surface and deposition of clusters of metallic Li. Using ab initio simulations, we predict the operating voltage for the occurrence of the above processes and safety measures to prevent dendrite growth in batteries. We find that Li deposition occurs in the following stages: at positive voltages vs. Li, surface deposition of Li+ ions is the dominant process. Below a critical cross-over voltage, the process of reduction of aggregated Li+ ions and the formation of metallic Li clusters takes over. This cross-over voltage is found to be −12 mV on the basal plane of unlithiated graphite and −29 mV on lithiated graphite. To prevent formation of Li clusters and for safe operation of Li-ion batteries, the voltage on the graphite anode should be kept above the cross-over value.

  • Melanoma skin cancer detection using mask-RCNN with modified GRU model
    • K. M. Monica
    • J. Shreeharsha
    • Przemysław Falkowski-Gilski
    • Bożena Falkowska-Gilska
    • Mohan Awasthy
    • Rekha Phadk
    2024 Pełny tekst Frontiers in Physiology

    Introduction: Melanoma Skin Cancer (MSC) is a type of cancer in the human body; therefore, early disease diagnosis is essential for reducing the mortality rate. However, dermoscopic image analysis poses challenges due to factors such as color illumination, light reflections, and the varying sizes and shapes of lesions. To overcome these challenges, an automated framework is proposed in this manuscript. Methods: Initially, dermoscopic images are acquired from two online benchmark datasets: International Skin Imaging Collaboration (ISIC) 2020 and Human against Machine (HAM) 10000. Subsequently, a normalization technique is employed on the dermoscopic images to decrease noise impact, outliers, and variations in the pixels. Furthermore, cancerous regions in the pre-processed images are segmented utilizing the mask-faster Region based Convolutional Neural Network (RCNN) model. The mask-RCNN model offers precise pixellevel segmentation by accurately delineating object boundaries. From the partitioned cancerous regions, discriminative feature vectors are extracted by applying three pre-trained CNN models, namely ResNeXt101, Xception, and InceptionV3. These feature vectors are passed into the modified Gated Recurrent Unit (GRU) model for MSC classification. In the modified GRU model, a swish-Rectified Linear Unit (ReLU) activation function is incorporated that efficiently stabilizes the learning process with better convergence rate during training. Results and discussion: The empirical investigation demonstrate that the modified GRU model attained an accuracy of 99.95% and 99.98% on the ISIC 2020 and HAM 10000 datasets, where the obtained results surpass the conventional detection models.

  • Meldrum’s acid assisted formation of tetrahydroquinolin‑2‑one derivatives a short synthetic pathway to the biologically useful scaffold
    • Małgorzata Ryczkowska
    • Alicja Trocka
    • Anna Hromova
    • Sławomir Makowiec
    2024 Pełny tekst Scientific Reports

    A new method for the preparation of tetrahydroquinolin-2-one derivatives is presented. This approach involves a two-step reaction between enaminones and acylating agents, immediately followed by electrophilic cyclization, all within a single synthesis procedure, eliminating the need to isolate intermediates. The entire process is facilitated by the use of acyl Meldrum’s acids which not only shortens the preparation time of the substrates but also easily extends the range of substituents That can be used. The method’s scope and limitations were evaluated with various reagent combinations thus demonstrating its general applicability to the synthesis of tetrahydroquinolin-2-one core. Interestingly, some exceptions to the regular reaction pathway were observed when a strong EDG (electron donating group) was introduced via acyl Meldrum’s acids. The underlying mechanism of this phenomenon was elucidated during the investigation.

  • MEMS Modeling in the Context of Inertial Navigation
    • Jerzy Demkowicz
    2024 International Journal of Electronics and Telecommunications

    Underwater navigation is a research topic current undertaken in many areas of underwater research. The article presents an analysis resulting from MEMS modelling in the context of inertial navigation. The ideal approach was confronted with its limitations, but a non-linear approach, close to the real one, was also presented. Both models were compared in the context of inertial navigation. Random disturbances and their impact on linear and nonlinear dynamic systems, and in this context on Brownian noise motion, were also analysed. The linear velocity and displacement estimates generated by the presented models were compared to the ideal responses. The phenomenon of bifurcation in the context of inertial measurements is presented. Some of the analysis is performed on real data, but for greater clarity, some is performed on simulated data to highlight design issues and limitations.

  • Merton-type default risk and financial performance: the dynamic panel moderation of firm size
    • Muhammad Mushafiq
    • Syed Ahmad Sami
    • Muhammad Khalid Sohail
    • Muzammal Ilyas Sindhu
    2024 Journal of Economic and Administrative Sciences

    Purpose – The main purpose of this study is to evaluate the probability of default and examine the relationship between default risk and financial performance, with dynamic panel moderation of firm size. Design/methodology/approach – This study utilizes a total of 1,500 firm-year observations from 2013 to 2018 using dynamic panel data approach of generalized method of moments to test the relationship between default risk and financial performance with the moderation effect of the firm size. Findings – This study establishes the findings that default risk significantly impacts the financial performance. The relationship between distance-to-default (DD) and financial performance is positive, which means the relationship of the independent and dependent variable is inverse. Moreover, this study finds that the firm size is a significant positive moderator between DD and financial performance. Practical implications – This study provides new and useful insight into the literature on the relationship between default risk and financial performance. The results of this study provide investors and businesses related to nonfinancial firms in the Pakistan Stock Exchange (PSX) with significant default risk’s impact on performance. This study finds, on average, the default probability in KSE ALL indexed companies is 6.12%. Originality/value – The evidence of the default risk and financial performance on samples of nonfinancial firms has been minimal; mainly, it has been limited to the banking sector. Moreover, the existing studies have only catered the direct effect of only. This study fills that gap and evaluates this relationship in nonfinancial firms. This study also helps in the evaluation of Merton model’s performance in the nonfinancial firms.

  • Mesoscopic simulations of a fracture process in reinforced concrete beam in bending using a 2D coupled DEM/micro-CT approach
    • Michał Nitka
    • Andrzej Tejchman-Konarzewski
    2024 Pełny tekst ENGINEERING FRACTURE MECHANICS

    W tej pracy zbadano numerycznie w warunkach 2D złożony proces pękania w krótkiej prostokątnej belce betonowej wzmocnionej jednym prętem podłużnym (bez zbrojenia pionowego) i poddanej quasi-statycznemu zginaniu w trzech punktach. Krytyczne pęknięcie poprzeczne w belce spowodowało jej uszkodzenie podczas doświadczenia. Symulacje numeryczne przeprowadzono klasyczną metodą elementów dyskretnych (DEM). Przyjęto trójfazowy opis betonu: kruszywa, zaprawa i międzyfazowe strefy przejściowe (ITZ) wokół kruszyw. W mezoskopowych obliczeniach DEM opartych na skanach rentgenowskich CT 2D przyjęto rzeczywisty kształt i połączenie cząstek kruszywa w betonie. W obliczeniach odtworzono pręt stalowy z żebrami. Założono także ITZ pomiędzy prętem a zaprawą. Bez narzucania prawa poślizgu, uwzględniono warunek geometryczny na granicy pręt/beton. W pracy skupiono się na wykresie siła-ugięcia, procesie pękania, siłach kontaktowych i naprężeniach wzdłuż pręta. Uzyskano dobry poziom zgodności ewolucji siły pionowej w zależności od ugięcia i mechanizmu zniszczenia w analizach DEM w porównaniu z testami laboratoryjnymi pomimo przyjęcia uproszczonych warunków 2D. Wykazano silny wpływ mezostruktury betonu na wzór pęknięcia.

  • Method for prediction of the frost resistance ability of air‐entrained concrete based on the 3D air void characteristics by x‐ray micro‐CT
    • Łukasz Skarżyński
    • Mikołaj Miśkiewicz
    2024 Structural Concrete

    In modern construction, one of the most important factors in the execution of contracts is time. Standard procedures for assessing the frost resistance or concrete are usually very time-consuming and can take up to 40 days. The current paper is experimentally and practically oriented. It presents an alternative testing method, based on air void network, that allows to assess the frost resistance of concrete within just a few days of taking the samples. X-ray micro-CT scans were introduced to obtain the quantitative and qualitative 3D information about the air void microstructure taking into account total air content: A [%], pores of the size below 300 μm in diameter content: A300 [%], specific surface of air voids: α [mm-1] and spacing factor: L [mm] in order to predict the freeze / thaw durability. To verify the assumptions of the frost resistance method, based on the analysis of pore microstructure, tests of freeze / thaw resistance in accordance with Polish supplement to European Standard [46] were carried out. Presented research revealed that the appropriate microstructure of air pores, in particular, content of micropores with the diameter less than 0.3 mm: A300 combined with a spacing factor: L [mm] can constitute a reliable basis for determining concrete freeze / thaw durability. Thus, method proposed in current paper can be effectively used for fast and trustworthy determination of the air-entrained concrete durability in a short time and without any special preparation of the tested sample, that allows immediate preventive or repair actions to be taken if required.

  • Method of Forming Road Surface Replicas Using 3D Printing Technology
    • Wojciech Owczarzak
    • Sławomir Sommer
    • Grzegorz Ronowski
    2024 Coatings

    Rolling resistance is a critical factor that influences vehicle energy consumption, emissions, and overall performance. It directly impacts fuel efficiency, tire longevity, and driving dynamics. Traditional rolling resistance tests are conducted on smooth steel drums, which fail to replicate real-world road surface textures, potentially skewing results. This article presents the process of designing surface replicas using 3D printing technology, which consisted of selecting the internal structure, material, and print parameters of the surface sample. In order to verify the designed structures, an original mechanical strength test was performed. The test was based on pressing the tire onto the test sample with an appropriate force that corresponded to typical conditions during rolling resistance measurements. The test results included surface texture profiles before and after the application of load, which were then superimposed to detect any possible sample deformation. The obtained strength test results confirmed the validity of using 3D printing technology in the process of obtaining road surface replicas.

  • Methodology Approach for Microplastics Isolation from Samples Containing Sucrose
    • Kornelia Kadac-Czapska
    • Beata Bochentyn
    • Aleksandra Maślarz
    • Sebastian Mahlik
    • Małgorzata Grembecka
    2024 MOLECULES

    The growing production and use of plastics significantly contribute to microplastics (MPs) contamination in the environment. Humans are exposed to MPs primarily through the gastrointestinal route, as these particles are present in beverages and food, e.g., sugar. Effective isolation and identification of MPs from food is essential for their elimination. This study aimed to evaluate factors influencing the isolation of MPs from sucrose solutions to determine optimal conditions for the process. Polyethylene particles were used to test separation methods involving chemical digestion with acids and filtration through membrane filters made of nylon, mixed cellulose ester, and cellulose acetate with pore sizes of 0.8 and 10 µm. The effects of temperature and acid type and its concentration on plastic particles were examined using scanning electron microscopy and µ-Raman spectroscopy. The results indicate that increased temperature reduces solution viscosity and sucrose adherence to MPs’ particles, while higher acid concentrations accelerate sucrose hydrolysis. The optimal conditions for MPs’ isolation were found to be 5% HCl at 70 ◦C for 5 min, followed by filtration using an efficient membrane system. These conditions ensure a high recovery and fast filtration without altering MPs’ surface properties, providing a reliable basis for further analysis of MPs in food.

  • Methodology of generation of CFD meshes and 4D shape reconstruction of coronary arteries from patient-specific dynamic CT
    • Krzysztof Psiuk-Maksymowicz
    • Damian Borys
    • Bartlomiej Melka
    • Maria Gracka
    • Wojciech Adamczyk
    • Marek Rojczyk
    • Jaroslaw Wasilewski
    • Jan Głowacki
    • Mariusz Kruk
    • Marcin Nowak
    • Ziemowit Ostrowski
    • Ryszard Bialecki
    2024 Pełny tekst Scientific Reports

    Due to the difficulties in retrieving both the time‑dependent shapes of the vessels and the generation of numerical meshes for such cases, most of the simulations of blood flow in the cardiac arteries use static geometry. The article describes a methodology for generating a sequence of time‑dependent 3D shapes based on images of different resolutions and qualities acquired from ECG‑gated coronary artery CT angiography. The precision of the shape restoration method has been validated using an independent technique. The original proposed approach also generates for each of the retrieved vessel shapes a numerical mesh of the same topology (connectivity matrix), greatly simplifying the CFD blood flow simulations. This feature is of significant importance in practical CFD simulations, as it gives the possibility of using the mesh‑morphing utility, minimizing the computation time and the need of interpolation between boundary meshes at subsequent time instants. The developed technique can be applied to generate numerical meshes in arteries and other organs whose shapes change over time. It is applicable to medical images produced by other than angio‑CT modalities.

  • Methods for Quality Assessment of Window View
    • Barbara Matusiak
    • Filomena Russo
    • Mandana Khanie, Sarey
    • Natalia Sokół
    • Christina Hemauer
    • Klaus Martiny
    • Carlo Volf
    • Siegrun Appelt
    • Natalia Giraldo Vasquez
    • Aicha Diakite-Kortlever
    2024 Pełny tekst Land

    This paper summarises findings from two workshops evaluating a series of views in various settings by an interdisciplinary group of experts. In the first one (Trondheim, June 2022), ten experts visited and assessed views from nine rooms. In the second one (Lausanne, June 2023), eleven experts assessed window views from four spaces. The workshops’ main objective was to develop and test multi-method assessments of window views. During both workshops, participants completed a survey that included close and open-ended questions about the perceived quality of the room and the view. Participants also measured lux level, took photographs, made hand drawings of the view, and answered a questionnaire about their mood and the environmental conditions in the room. After the workshop, point-in-time daylight simulations were performed for the visited rooms. The paper describes, compares, and recommends the use of the aforementioned methods depending on the type and complexity of the view, and the space, the evaluators’ professional background, and the type of collected data. It also discusses the overlap of the methods and estimates the preparation time, time spent on site, and the amount of work after the visit. Finally, it recommends the use of the tested methods depending on the application.

  • Miasta Nieskończone. Warsztaty animacji poklatkowej doodle-art. Bałtycki Festiwal Nauki 2024
    • Marta Koperska-Kośmicka
    • Agnieszka Kurkowska
    • Aleksandra Karpińska
    2024

    Warsztaty animacji poklatkowej w technice doodle-art, podczas których uczestnicy stworzyli wspólnie animowany film o mieście marzeń. Warsztaty z animacji poklatkowej są zajęciami rozwijającymi wyobraźnię i kreatywność. Film powstawał zespołowo, poprzez dodawanie nowych elementów rysunku przez każdego z uczestników. Kolejne fazy powstawania wymarzonego miasta zostały uwiecznione na zdjęciach, które po cyfrowej obróbce pozwoliły na stworzenie krótkiego, jednominutowego animowanego filmu.

  • Micro- and nano-Illite to improve strength of untreated-soil as a nano soil-improvement (NSI) technique
    • M Cheraghalikhani,
    • Hamed Niroumand
    • Lech Bałachowski
    2024 Pełny tekst Scientific Reports

    Soil stabilization is a technique of improving the geotechnical properties of soils for various engineering applications. However, conventional stabilizers such as cement and lime have some limitations, such as high cost, environmental impact, and durability issues. Therefore, there is a need for alternative and innovative stabilizers that can overcome these challenges. This study introduces nano-Illite, a type of clay mineral, as a novel and efective soil stabilizer. Nano-Illite can form nano-cementation (NC) in soil, which is a process of enhancing the durability of various building materials. NC is also known as nano soil-improvement (NSI), a technique that has been developed in recent years. Four formulations of micro- and nano-Illite with concentrations of 0, 1, 2, and 3% were separately added to soil samples. The unconfned compressive strength (UCS) and the secant modulus at 50% of peak stress (E50) of the treated samples were measured and compared with the untreated samples. The results showed that 3% nano-Illite increased the UCS of soil by more than 2.2 times and the E50 by more than 1.5 times after 7 days of curing. Micro-Illite also improved the UCS and E50 of soil, but to a lesser extent. X-ray fuorescence (XRF), scanning electron microscopy (SEM), and X-ray difraction (XRD) analyses revealed the micro- and nano-structures of the soil specimens and the performance of Illite as a nano-additive. This research demonstrates the efectiveness of nano-Illite in soil improvement as a NSI technique, and its potential to replace or reduce the use of conventional stabilizers. This study also contributes to the understanding of the mechanisms and factors that infuence the NC process in soil.

  • Microbe Cultivation Guidelines to Optimize Rhamnolipid Applications
    • Ilona Kłosowska-Chomiczewska
    • Adam Macierzanka
    • Karol Parchem
    • Pamela Miłosz
    • Sonia Sarach
    • Iga Płaczkowska
    • Weronika Hewelt-Belka
    • Christian Jungnickel
    2024 Pełny tekst Scientific Reports

    In the growing landscape of interest in natural surfactants, selecting the appropriate one for specific applications remains challenging. The extensive, yet often unsystematized, knowledge of microbial surfactants, predominantly represented by rhamnolipids (RLs), typically does not translate beyond the conditions presented in scientific publications. This limitation stems from the numerous variables and their interdependencies that characterize microbial surfactant production. We hypothesized that a computational recipe for biosynthesizing RLs with targeted applicational properties could be developed from existing literature and experimental data. We amassed literature data on RL biosynthesis and micellar solubilization and augmented it with our experimental results on the solubilization of triglycerides (TGs), a topic underrepresented in current literature. Utilizing this data, we constructed mathematical models that can predict RL characteristics and solubilization efficiency, represented as logPRL = f(carbon and nitrogen source, parameters of biosynthesis) and logMSR = f(solubilizate, rhamnolipid (e.g. logPRL), parameters of solubilization), respectively. The models, characterized by robust R2 values of respectively 0.581-0.997 and 0.804, enabled the ranking of descriptors based on their significance and impact — positive or negative — on the predicted values. These models have been translated into ready-to-use calculators, tools designed to streamline the selection process for identifying a biosurfactant optimally suited for intended applications.

  • Microextraction by packed sorbent: Uncommon detection techniques, sorbents, samples and analytes
    • Vasil Andruch
    • Alina Kalyniukova
    • Tanya Yordanova
    • Justyna Płotka-Wasylka
    • Viera Vojteková
    • Gokhan Zengin
    2024 TRAC-TRENDS IN ANALYTICAL CHEMISTRY

    Among sample preparation approaches, the most desirable are procedures that ensure high efficiency and reproducibility, that are cheap, fast and simple, that minimize the number of operational steps and that require a small amount of sample and solvent and are thus environmentally friendly. Microextraction by packed sorbent (MEPS) is a miniaturized form of solid-phase extraction, the use of which has been continuously expanding since its introduction in 2004. This technique can be considered green, and due to its many advantages, it has been widely accepted and used for sample pretreatment prior to instrumental analysis. This mini-review deals with the presentation and discussion of atypical, less described approaches and solutions with the MEPS technique, especially in regard to the detection techniques and sorbents used, the samples analyzed and the analytes determined. We hope this review will interest, inspire and motivate readers to explore new MEPS applications.

  • Microfluidically Frequency-Reconfigurable Compact Self-Quadruplexing Tunable Antenna with High Isolation Based on Substrate Integrated Waveguide
    • Rusan Kumar Barik
    • Sławomir Kozieł
    2024 Pełny tekst Scientific Reports

    This communication presents a novel concept of microfluidically frequency-reconfigurable self-quadruplexing tunable antenna for quad-band applications. At the initial design stage, a substrate-integrated square cavity is divided into four unequal quarter-mode cavity resonators by inserting an X-shaped slot on the top surface of the cavity. Applying four 50-ohm microstrip feed-lines to these four quarter-mode cavity resonators enables quad-band operation with self-quadruplexing capabilities. The feed lines are organized orthogonally and off-center, which leads to port isolation greater than 32.3 dB. An equivalent network model is developed to validate the proposed antenna. To realize frequency reconfigurability, two microfluidic channels corresponding to each port are created by engraving the bottom surface of the cavity. To create a reconfigurable self-quadruplexing antenna, the channels are either filled with air or dielectric liquids of higher permittivity, so that the design offers independent tunability of the operating frequencies. As a proof of concept, the prototype of a self-quadruplexing tunable antenna is fabricated and validated through measurements. The antenna prototype occupies a footprint area of 0.37λg2. The design exhibits frequency tuning ranges of 350 MHz (8.3%), 500 MHz (10.3%), 610 MHz (11.2%), and 845 MHz (14.1%) for the first, second, third, and fourth operating bands, respectively. In all bands and across the entire tuning range, the realized gains of the designed antenna exceed 4.05 dBi. The electromagnetic modeling responses agree extremely well with the measured characteristics.

  • Microfluidically Frequency-Reconfigurable Self-Quadruplexing Antenna Based on Substrate Integrated Square-Cavity
    • Rusan Kumar Barik
    • Sławomir Kozieł
    2024 AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS

    In this article, a novel concept of self-quadruplexing tunable antenna (SQTA) enabled by microfluidic channels is investigated. The operating channels are either filled with air or dielectric liquids to enable frequency tunability. The proposed SQTA is implemented on the substrate-integrated square-cavity (SISC). A swastika-shaped slot is milled on the top-surface of the SISC to create four quarter-mode resonators. The resonators are excited by four 50-Ω microstrip lines to enable independent operating bands with self-quadruplexing properties. The working principle is validated by a custom-developed lumped-circuit model. The port isolations are better than 27dB due to the orthogonal and off-centered port allocation. Subsequently, two microfluidic channels corresponding to each quarter-mode resonator are milled from bottom-surface of the cavity. These two channels are filled with liquids of various permittivity to achieve frequency tunability. As a proof-of-concept, a prototype of the proposed SQTA is fabricated and demonstrated experimentally. The fabricated SQTA operates at 4.05-4.56 GHz, 4.645-5.295 GHz, 5.45-6.325 GHz, and 6.19-7.265 GHz. The measured realized gains of the SQTA are 4.4-4.5 dBi, 4.5-4.6 dBi, 4.8-4.9 dBi, and 4.9-4.95 dBi.

  • Microplastics in water resources: Global pollution circle, possible technological solutions, legislations, and future horizon
    • Saeed S. Albaseer
    • Hussein Al-Hazmi
    • Tonni Agustiono Kurniawan
    • Xianbao Xu
    • Sameer A.M. Abdulrahman
    • Peyman Ezzati
    • Sajjad Habibzadeh
    • Henner Hollert
    • Navid Rabiee
    • Eder C. Lima
    • Michael Badawi
    • Mohammad Saeb
    2024 SCIENCE OF THE TOTAL ENVIRONMENT

    Beneath the surface of our ecosystems, microplastics (MPs) silently loom as a significant threat. These minuscule pollutants, invisible to the naked eye, wreak havoc on living organisms and disrupt the delicate balance of our environment. As we delve into a trove of data and reports, a troubling narrative unfolds: MPs pose a grave risk to both health and food chains with their diverse compositions and chemical characteristics. Nevertheless, the peril extends further. MPs infiltrate the environment and intertwine with other pollutants. Worldwide, microplastic levels fluctuate dramatically, ranging from 0.001 to 140 particles.m-3 in water and 0.2 to 8766 particles.g-1 in sediment, painting a stark picture of pervasive pollution. Coastal and marine ecosystems bear the brunt, with each organism laden with thousands of microplastic particles. MPs possess a remarkable ability to absorb a plethora of contaminants, and their environmental behavior is influenced by factors such as molecular weight and pH. Reported adsorption capacities of MPs vary greatly, spanning from 0.001 to 12,700 μg·g−1. These distressing figures serve as a clarion call, demanding immediate action and heightened environmental consciousness. Legislation, innovation, and sustainable practices stand as indispensable defenses against this encroaching menace. Grasping the intricate interplay between microplastics and pollutants is paramount, guiding us toward effective mitigation strategies and preserving our health ecosystems.

  • Microstructural evolution and mechanical behavior of activated tungsten inert gas welded joint between P91 steel and Incoloy 800HT
    • Vishwa Bhanu
    • J. Manoj
    • Ankur Gupta
    • Dariusz Fydrych
    • Chandan Pandey
    2024 INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY

    This study examines the welded joint between P91 steel and Incoloy 800HT using the Activated Tungsten Inert Gas (A-TIG) welding process. The focus is on analyzing the microstructure and evaluating the mechanical properties of joints made with different compositions of activating flux. Owing to the reversal of the Marangoni effect in which the conventional direction of molten metal flow in the weld pool is reversed due to the application of oxide-based fluxes, a complete depth of penetration of 8 mm was successfully achieved. Conducting mechanical tests, such as microhardness, tensile, and Charpy impact toughness tests, elucidates the behavior of the welded specimens under different loading conditions. The findings highlight the effects of grain size, dislocations, and the evolution of fine-sized precipitates in the high-temperature matrix. This study highlights the importance of choosing suitable flux compositions to achieve consistent penetration and dilution in the base metals. Insights into different failure modes and the influence of temperature on the tensile strength were evaluated. Beneficial mechanical properties of the joints (meeting the criteria of ISO and ASTM standards) were found: ultimate tensile strength of 585 ± 5 MPa, elongation 38 ± 2%, impact toughness of 96  5 J, and maximum microhardness of 345 ± 5 HV.

  • Microstructure and mechanical properties of a dissimilar metal welded joint of Inconel 617 and P92 steel with Inconel 82 buttering layer for AUSC boiler application
    • Amit Kumar
    • Sachin Sirohi
    • Manohar Singh
    • Dariusz Fydrych
    • Chandan Pandey
    2024 INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING

    The application of the novel dissimilar metal welded (DMW) joint, utilizing Inconel 617 and P92 steel, was showcased in the advanced ultra-supercritical (AUSC) boiler. The work has been performed to investigate the effect of Inconel 82 (ERNiCr-3) buttering layer on microstructure and mechanical properties (high-temperature tensile strength, impact strength and microhardness) of gas tungsten arc welded (GTAW) dissimilar joint between Inconel 617 and P92 steel fabricated using the Inconel 617 (ERNiCrCoMo-1) filler. For optical microscopy and scanning electron microscopy (SEM), samples were machined along a transverse direction which comprised the butter layer, weld metal, and heat-affected zone of both sides. The energy-dispersive X-ray spectroscopy (EDS) was used to map the interface of the buttering layer and weld metal and butter layer and P92 steel. The high-temperature tensile testing and Charpy impact testing at room temperature were conducted for the integrity assessment of the welded joint. The examination of microstructure and hardness revealed that the buttering layer of Inconel 82 filler successfully mitigated a significant portion of the brittle martensitic microstructure from the coarse-grained heat-affected zone (CGHAZ), along with hardness peaks on the side of P92 steel. The conventional method of DMW joint fabrication, without the use of a buttering layer, has been demonstrated to be less favourable compared to the new fabrication method, which incorporates a buttering layer. The TiC/NbC carbides were identified in the Inconel 82 buttering layer, whereas M23C6 and Mo6C carbides were found in the Inconel 617 filler weld. Near the interface of the Inconel 82 buttering layer and P92 steel, the formation of peninsula and island structures, as well as Type I and Type II boundaries, were confirmed. Additionally, element diffusion of Ni, Cr, and Fe was observed. The tensile test results indicated an ultimate tensile strength of 620 ± 4 MPa and % elongation of 19 ± 4 % at room temperature, with fracture occurring in the buttering layer near the interface of the buttering layer and P92 steel. At temperatures of 550 °C and 650 °C, the ultimate tensile strength decreased to 448 MPa and 326 MPa, respectively, with fractures occurring in the P92 steel, irrespective of temperature. The hardness of the Inconel 82 buttering layer and Inconel 617 filler weld were 219 ± 10 HV and 248 ± 11 HV, respectively.

  • Microwave-Induced Processing of Free-Standing 3D Printouts: An Effortless Route to High-Redox Kinetics in Electroanalysis
    • Kornelia Kozłowska
    • Mateusz Cieślik
    • Adrian Koterwa
    • Krzysztof Formela
    • Jacek Ryl
    • Paweł Niedziałkowski
    2024 Materials

    3D-printable composites have become an attractive option used for the design and manufacture of electrochemical sensors. However, to ensure proper charge-transfer kinetics at the electrode/electrolyte interface, activation is often required, with this step consisting of polymer removal to reveal the conductive nanofiller. In this work, we present a novel effective method for the activation of composites consisting of poly(lactic acid) filled with carbon black (CB-PLA) using microwave radiation. A microwave synthesizer used in chemical laboratories (CEM, Matthews, NC, USA) was used for this purpose, establishing that the appropriate activation time for CB-PLA electrodes is 15 min at 70 °C with a microwave power of 100 W. However, the usefulness of an 80 W kitchen microwave oven is also presented for the first time and discussed as a more sustainable approach to CB-PLA electrode activation. It has been established that 10 min in a kitchen microwave oven is adequate to activate the electrode. The electrochemical properties of the microwave-activated electrodes were determined by electrochemical techniques, and their topography was characterized using scanning electron microscopy (SEM), Raman spectroscopy, and contact-angle measurements. This study confirms that during microwave activation, PLAs decompose to uncover the conductive carbon-black filler. We deliver a proof-of-concept of the utility of kitchen microwave-oven activation of a 3D-printed, free-standing electrochemical cell (FSEC) in paracetamol electroanalysis in aqueous electrolyte solution. We established satisfactory limits of linearity for paracetamol detection using voltammetry, ranging from 1.9 μM to 1 mM, with a detection limit (LOD) of 1.31 μM.

  • Mieszanki betonowe stosowane w technologii druku trójwymiarowego
    • Andrzej Ambroziak
    2024 Przegląd Budowlany

    W niniejszej pracy dokonano przeglądu literatury z zakresu mieszanek i zapraw betonowych stosowanych w druku trójwymiarowym. Przegląd literatury przygotowano z zachowaniem chronologii pojawienia się danej publikacji (daty publikacji). Na podstawie przeprowadzonego przeglądu dokonano tabelarycznego zestawienia receptur mieszanek wykorzystywanych w wydrukach trójwymiarowych (3D). Przedstawiony przegląd literatury z zakresu mieszanek i zapraw betonowych stosowanych w druku trójwymiarowym można traktować jako wstęp do szczegółowych badań związanych z projektowaniem nowych typów mieszanek i receptur.

  • Migration of trace elements and radioisotopes to various fractions of solid wastes generated as a result of the sewage sludge incineration process
    • Oskar Ronda
    • Bartłomiej Cieślik
    • Barbara Piotrowska
    • Krzysztof Isajenko
    • Satoki Okabayashi
    • Koichi Chiba
    • Motohiro Tsuboi
    • Justyna Płotka-Wasylka
    2024 Pełny tekst WASTE MANAGEMENT

    The research was aimed at providing new knowledge in the field of chemical characteristics of solid waste generated in the process of combustion of sewage sludge in fluidized bed furnaces. The research material consisted of disposed fluidized beds (DFB), sewage sludge ash (SSA) and air pollution control residues (APC) from three Polish installations for the thermal treatment of sewage sludge. Natural radionuclides as well as anthropogenic isotope 137Cs were determined in the tested materials and the migration of a wide spectrum of trace elements to various waste fractions generated in the process of sewage sludge combustion was examined. It was observed that both radioisotopes and most of the trace elements determined accumulate in SSA and DFB, while the APC fraction contains a much smaller amount of them. The exceptions are mercury and selenium, whose volatile compounds migrate to the exhaust gas dedusting system and accumulate in the APC fraction (up to 40 mg/kg and 13 mg/kg, respectively). A potential threat from the 226Ra isotope in SSA is identified in the context of the management of this waste in the production of building materials because the typical activity of 226Ra in SSA collected from areas with very low Ra content in natural environment exceeds 1.5–6 times the activity of this isotope in conventional cement mixtures. When managing SSA and DFB, special attention should be paid to the content of metalloids such as As, B and Se, due to the high content of mobile forms of these elements in the mentioned materials.

  • Millimeter Wave Negative Refractive Index Metamaterial Antenna Array
    • Rao Aziz
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2024 Pełny tekst Scientific Reports

    In this paper, a novel negative refractive index metamaterial (NIM) is developed and characterized. The proposed metamaterial exhibits negative effective permittivity (εeffe) and negative effective permeability (µeffe) at millimeter wave frequency of 28GHz. This attractive feature is utilized to enhance the gain of a microstrip patch antenna (MPA). Two thin layers of 5  5 subwavelength unit cell array of NIM are placed above a single MPA to enhance the gain of the antenna. Each unit cell has an area of 3.4  3.4 mm2. A gain increase of 7.9dBi has been observed when using the proposed NIM as a superstrate. Furthermore, the NIM array is placed over a 2  2 array of MPAs with four ports to demonstrate versatility of the metamaterial. The total size of the 2  2 antenna array system with N-MTM is about 61.1  34  16mm3 (5.71λ  3.18λ  1.5λ, where λ is the free-space wavelength at 28 GHz). The measurement result indicate that the maximum gain of the antenna array is 13.5dBi. A gain enhancement of 7.55 dB in E-Plane and 7.25 dB in H-Plane at the resonant frequency of 28 GHz is obtained. The proposed antenna structure is suitable for 5G millimeter wave communications, in particular, for possible implementation in future millimeter wave access points and cellular base stations.

  • Millimeter Wave Retrodirective Van Atta Arrays in LTCC Technology
    • Kamil Trzebiatowski
    • Martin Ihle
    • Benedykt Sikorski
    • Łukasz Kulas
    • Krzysztof Nyka
    2024

    The millimeter wave Van Atta arrays, intended for chipless RFID applications and fabricated in LTCC technology, are presented in this paper. The arrays are designed for 24 GHz and 60 GHz bands. The method for an easy modification of the RCS characteristic by increasing the number of single-dimensional arrays, intended for increasing the RCS level, is also presented. The LTCC manufacturing process is described in detail. The fabricated arrays are characterized in an anechoic chamber and exhibit RCS levels up to -26 dBsm with a small 51 x 17 mm footprint.