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Repozytorium publikacji
Politechniki Gdańskiej

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  • Zr‐Based Metal‐Organic Framework UiO‐66/Ultem® 1000 Membranes for Effective CO2/H2 Separation
    • Muhammad Imad
    • Roberto Castro Munoz
    • Milan Bernauer
    • Violeta Martin
    • Pavel Izak
    • Vlastimil Fíla
    2023 CHEMICAL ENGINEERING & TECHNOLOGY

    Mixed-matrix membranes (MMMs) using UiO-66 nanofillers as dispersing inorganic phase and polyetherimide (PEI) as continuous polymeric matrix were synthesized. Different UiO-66 loadings of 10, 20, and 30 wt % were applied. The morphology and UiO-66 dispersion over the prepared MMMs were examined. Gas separation measurements were performed for H2/CO2 gas mixture to evaluate the influence of UiO-66 on the separation yield of resulting membranes. When compared with pristine PEI membranes, MMMs containing metal-organic framework (MOF) nanoparticles revealed superior H2 permeability and H2/CO2 separation factor, e.g., maximum permeability values of 14.6 and 5.5 Barrer were observed for H2 and CO2 at a filler loading of 10 wt % and an applied pressure of 4.0 bar.

  • Zwalczanie przestępczości skarbowej jako aktywny sposób minimalizacji ryzyka podatkowego - case study
    • Piotr Kasprzak
    • Witold Witkowski
    • Jarosław Wróblewski
    2023

    Celem pracy jest prezentacja i ocena sposobów zwalczania przestępczości skarbowej jako jeden z podstawowych sposobów minimalizacji ryzyka podatkowego. Metodologia badania - analizie i ocenie poddano wybrane sposoby zwalczania przestępstw skarbowych. Dla osiągnięcia tego celu posłużono się zarówno analizą literatury, jak i materiałów pochodzących ze statystyk sporządzonych przez służby skarbowe oraz policję. Wyniki - wyniki dowodzą, że przestępcy ustawicznie doskonalą istniejące sposoby oszustw podatkowych oraz próbują wymyślić nowe, monitorując i wykorzystując zidentyfikowane luki i niedoskonałości systemu prawnego oraz administracyjnego, problemy w integracji działań poszczególnych służb itd. Istnieje więc potrzeba i konieczność opracowania zestawu skutecznych rozwiązań o charakterze kompleksowym, które będą mogły zostać wykorzystane w obszarze antyryzyka podatkowego. Wartość - praca prezentuje metody oraz narzędzia stosowane w celu zwalczania przestępczości podatkowej i zarządzania ryzykiem skarbowym, a także sposoby ich doskonalenia i integracji oraz koordynacji multidyscyplinarnych oraz wielowymiarowych działań, w celu zwiększenia ich efektywności.

  • 100– lecie urodzin profesora Romualda Kolmana 1922-2016, patrona Konkursu IKAR JAKOŚCI. Kamienie milowe w dorobku twórcy kwalitologii w Polsce
    • Piotr Grudowski
    2022 Pełny tekst MAG. Magazyn dla Praktyków

    17 czerwca 2022 roku minęła 100. rocznica urodzin śp. profesora dr. hab. inż. Romualda Kolmana, jednego z najczęściej przywoływanych twórców i krzewicieli Polskiej Szkoły Jakości. Jako podwładny i doktorant profesora w ostatnim, przypadającym na lata 90. XX wieku okresie jego pracy na Wydziale Mechanicznym Technologicznym w Politechnice Gdańskiej, miałem tę możliwość i szczęście, że mogłem zapoznać się z praktycznie całym dorobkiem naukowym jego życia. Dlatego też w związku z tą okrągłą rocznicą chciałbym w dużym skrócie przedstawić najważniejsze jego osiągnięcia związane z kwalitologią – wiedzą o jakości, którą pioniersko systematycznie rozwijał i upowszechniał.

  • 2D MXene nanocomposites: electrochemical and biomedical applications
    • Marzieh Ramezani Farani
    • Behnam Nourmohammadi Khiarak
    • Rui Tao
    • Zegao Wang
    • Sepideh Ahmadi
    • Mahnaz Hassanpour
    • Mohammad Rabiee
    • Mohammad Saeb
    • Eder C. Lima
    • Navid Rabiee
    2022 Environmental Science-Nano

    In recent years, key questions about the interaction of 2D MXene nanomaterials in electrochemical and biomedical applications have been raised. Most research has focused on clarifying the exclusive properties of the materials; however, only limited reports have described the biomedical applications of 2D nanomaterials. 2D MXenes are monolayer atomic nanosheets resulting from MAX phase ceramics. The hydrophilic properties, metallic conductivity, stability, and exclusive physiochemical performances make them promising materials for electrochemical and biomedical applications, including CO2 reduction, H2 evolution, energy conversion and storage, supercapacitors, stimuli-responsive drug delivery systems, regenerative medicine, and photothermal cancer therapy. In this review paper, we have provided facile approaches to synthesising MXene and characterization of chemical and physical properties. Their potential applications in medicine, ranging from antibacterial agents to targeted drug delivery, cancer photo/chemotherapy, tissue engineering, and electrochemical applications, have not been comprehensively reviewed and discussed—which encouraged us to come up with this work. We also discuss the most common challenges of utilizing MXene-related materials and areas that can be further developed in the future, with possible struggles and limitations one may face.

  • 3D DEM simulations of fracture in reinforced concrete beams
    • Michał Nitka
    • Andrzej Tejchman-Konarzewski
    2022

    Artykuł dotyczy zachowania się belki żelbetowej bez zbrojenia pionowego przy trzypunktowym zginaniu. Belka uległa zniszczeniu wskutek ścinania z powodu obecności nadmiernego zbrojenia podłużnego. Eksperymenty przeprowadzono w skali laboratoryjnej z wykorzystaniem systemu mikro-CT, a następnie odtworzono je w analizach numerycznych stosując metodą elementów dyskretnych 3D (DEM). Zastosowano 4-fazowy model betonu z mezostrukturą, oparty bezpośrednio na obrazach mikro-CT. Uzyskano zadowalającą zgodność między wynikami doświadczalnymi i numerycznymi w odniesieniu do lokalizacji i kierunku krytycznego makropęknięcia.

  • 3D X-ray Micro-CT Analysis of Rebar Corrosion in Reinforced Concrete Subjected to a Chloride-Induced Environment
    • Łukasz Skarżyński
    • Katarzyna Kibort
    • Aleksandra Małachowska
    2022 Pełny tekst MOLECULES

    The paper presents experimental investigations of the concrete cover protective ability to coun-teract rebar corrosion in reinforced concrete cubes. To study and quantify the consequences of corrosion a reinforced concrete sample was subjected to chloride-induced environment in order to get corroded and combined with un-corroded sample. Chloride-accelerated technique can in-duce a high degree of corrosion within at a controlled time. Moreover, detailed and thorough experimental measurements and analyses of reinforcement loss due to corrosion and its influ-ence on concrete microstructure was studied by means of 3D X-Ray micro-computed tomogra-phy. Whereas rebar outside the concrete was heavily corroded due to chloride-accelerated test, only local surface corrosion products appeared inside the concrete. It turned out, that in spite of accelerated corrosion environment, concrete cover shows protective ability to counteract rein-forcing steel corrosion mechanism. Moreover, bond strength between reinforcement rebar and concrete was not visibly affected since the failure force in pull-out test and failure mechanisms, observed by 3D X-Ray micro-CT, were similar for corroded and un-corroded sample. Failure took place due to presence of radial cracks with the maximum width equal approximately 0,25 mm.

  • 50’ Sail Catamaran with Hybrid Propulsion, Design, Theoretical and Experimental Studies
    • Wojciech Litwin
    • Daniel Piątek
    • Wojciech Leśniewski
    • Konrad Marszałkowski
    2022 Pełny tekst Polish Maritime Research

    The development of modern lithium batteries and propulsion systems now allows the use of complex propulsion systems for vessels of various sizes. As part of the research and implementation project, a parallel hybrid drive system was designed, built and then tested in the laboratory. The experimental studies conducted allowed for the measurements of power, fuel consumption and electric power distribution in various operating modes of the propulsion system. The research proves that in the analysed case, the hybrid parallel system meets the demand for electric energy during a typical cruise scenario, and thus there is no need to install a power generator on the yacht.

  • A breath of fresh air - social cognitive career theory in studying entrepreneurial intentions
    • Magdalena Licznerska
    • Paweł Ziemiański
    2022 International Journal of Entrepreneurship and Small Business

    A pinch of robustness and a pinch of freshness create an interesting story. That is why this study focuses on entrepreneurial intentions from an alternative theoretical perspective in an underexplored context. In this paper, it is argued that social cognitive career theory is relevant to the study of individual entrepreneurial cognition and behaviour, and it offers a solid framework in entrepreneurship research. This paper expands on SCCT’s conceptualisation of environmental determinants, proposing the examination of how a new combination of contextual factors (perceived educational, relational and structural support), entrepreneurial self-efficacy, individual entrepreneurial orientation and negative outcome expectations are related to entrepreneurial intentions. For this exploratory study, a questionnaire completed by a sample of students from Poland, one of the Central and Eastern European countries, was employed. Hierarchical multiple regression analyses revealed support for the role of SCCT variables in predicting entrepreneurial intentions. The results, which offer direct useful indications for further research activities, are presented and discussed.

  • A brief note on monotonic and fatigue fracture events investigation of thin-walled tubular austenitic steel specimens via fracture surface topography analysis (FRASTA)
    • Wojciech Macek
    • Dhinakaran Sampath
    • Łukasz Pejkowski
    • Krzysztof Żak
    2022 Pełny tekst ENGINEERING FAILURE ANALYSIS

    The main objective of this short communication is to show the fracture progression in each loading case and complement knowledge about fracture mechanisms underpinning the tensile and fatigue performance of thin-walled tubes. For this purpose, the fracture surface topography analysis (FRASTA) method was used in the thin-walled tubular austenitic stainless-steel specimens. Two cases were analyzed: monotonic tension, and uniaxial fully-reversed fatigue. Furthermore, the fractures topographies were quantified through the profiles over their entire surfaces with the support of an optical confocal measurement system. The results showed the usefulness of the FRASTA method in identifying characteristic zones in the cracking process for the analyzed cases and motivates its development for other materials and complex loading cases.

  • A Case Study on Implementing Agile Techniques and Practices: Rationale, Benefits, Barriers and Business Implications for Hardware Development
    • Paweł Weichbroth
    2022 Pełny tekst Applied Sciences-Basel

    Agile methodologies, along with the corresponding tools and practices, are claimed to facilitate teams in managing their work more effectively and conducting their work more efficiently while fostering the highest quality product within the constraints of the budget. Therefore, the rate of awareness and adoption of Agile frameworks both within and outside the software industry has increased significantly. Yet, the latest studies show that the adoption of Agile techniques and practices are not one-size-fits-all, and highlight the challenges, risks, and limitations regarding numerous domains. In this regard, the state-of-the-art literature provides comprehensive reading. However, in the case of hardware manufacturing, it seems to be sparse and fragmented. To fill this gap, the goal of this study is to analyze and present an in-depth account of the implementation of mix agile-oriented tools and practices. To tackle this goal, a single industry case study was undertaken, based on the primary data obtained through the interview protocol and the secondary data extracted from the project’s documentation. The findings concern three areas. First, the rationale behind the implementation of agile for hardware development is explained. Second, the implemented agile techniques and practices are identified, as well as the supporting tools through which their adoption was successfully undertaken. Third, the areas positively impacted by their application are highlighted with the corresponding evaluation measures deployed; moreover, the barriers to adopting Agile practices encountered, and the benefits gained from particular techniques, are further discussed. The presented findings might be of great importance for both researchers and practitioners who are searching for empirical evidence regarding Agile-oriented implementations. Finally, in terms of both benefits and barriers, business implications for hardware development are formulated. Alongside this, numerous open issues and questions present interesting research avenues that concern, in particular, the effectiveness of collaboration and areas of communication through the lens of agile techniques and practices.

  • A Circular Waveguide Dual-Mode Filter With Improved Out-of-Band Performance for Satellite Communication Systems
    • Michał Baranowski
    • Łukasz Balewski
    • Adam Lamęcki
    • Michał Mrozowski
    • Jaione Galdeano
    2022 Pełny tekst IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS

    This letter presents a novel design for a 3-D-printed circular waveguide dual-mode (CWDM) filter with a modified cavity shape. The modification leads to a wide spurious-free stopband, which is highly desirable for channel separation in waveguide contiguous output multiplexers (OMUXs) in satellite communication systems. The new resonant cavity design is a result of applying shape deformation to a basic circular cavity in order to move away and suppress parasitic modes. A fourth-order Ku-band channel filter with two transmission zeros (TZs) is designed, fabricated by additive manufacturing (AM) in one piece and measured. In comparison with the state-of-the-art design of a stepped CWDM filter, an improvement of approximately 35% wider spurious-free range is achieved.

  • A city is not a tree: a multi-city study on street network and urban life
    • Jianxiang Huang
    • Yuming Cui
    • Haoliang Chang
    • Hanna Obracht-Prondzyńska
    • Dorota Kamrowska-Załuska
    • Lishuai Li
    2022 Pełny tekst LANDSCAPE AND URBAN PLANNING

    Christopher Alexander, a British-American scholar, differentiated an old (natural) city from a new (planned) one by structure. The former resembles a “semilattice”, or a complex system encompassing many interconnected sub-systems. The latter is shaped in a graph-theoretical “tree”, which lacks the structural complexity as its sub-systems are compartmentalized into a single hierarchy. This structural distinction explains why, or perhaps determines “the patina of life” in old urban districts and the lack of such in new ones. His idea, although widely influential, remains contested for its lack of empirical evidence. Subsequent literature failed to distinguish the structural differences between the old and new cities in systematic ways, nor is his hypothesized structure-life relationship verified with statistical rigor. This study aims to test Alexander’s urban structural theory under a comprehensive research framework. We translated his constructs and premises into a mathematically testable form. Qualities of urban spatial structure, such as “semilattice”, “complex network” and “living structure”, were measured using graph-topological indicators computed for street networks. Urban life was measured using a combination of Twitter activities, Point-Of-Interests, and walking trips at the district level. The structure-life relationship was examined using statistical models, after controlling for urban form and socio-demographic confounders including land use, density, block size, parks, income, age, and demographic groups. This research design was implemented in London, New York, Hong Kong, and Gdansk. Our results support Alexander's early works that an old urban district contains more “semilattice” compared with new ones. This quality can be consistently captured by Meshedness Coefficient, a graph-network indicator for semilattice-shaped street network and a strong predictor for urban life. The same cannot be observed for “complex network” with consistency, while we found no independent associations between “living structure” and life, contrary to existing literature. The study shed light on the hidden relationship between urban spatial structure and behavioral evidence in both the virtual and physical world. We uncovered the British-American predilection of Alexander’s theory, which matched data closely in London and New York, but less so in Hong Kong and Gdansk, suggesting the need for a locally-sensitive approach.

  • A coarse‐grained approach to NMR ‐data‐assisted modeling of protein structures
    • Emilia Lubecka
    • Adam Liwo
    2022 Pełny tekst JOURNAL OF COMPUTATIONAL CHEMISTRY

    The ESCASA algorithm for analytical estimation of proton positions from coarse-grained geometry developed in our recent work has been implemented in modeling protein structures with the highly coarse-grained UNRES model of polypeptide chains (two sites per residue) and nuclear magnetic resonance (NMR) data. A penalty function with the shape of intersecting gorges was applied to treat ambiguous distance restraints, which automatically selects consistent restraints. Hamiltonian replica exchange molecular dynamics was used to carry out the conformational search. The method was tested with both unambiguous and ambiguous restraints producing good-quality models with GDT_TS from 7.4 units higher to 14.4 units lower than those obtained with the CYANA or MELD software for protein-structure determination from NMR data at the all-atom resolution. The method can thus be applied in modeling the structures of flexible proteins, for which extensive conformational search enabled by coarse-graining is more important than high modeling accuracy.

  • A Compact and Lightweight Microwave Tilt Sensor Based on an SRR-Loaded Microstrip Line
    • Ali Karami Horestani
    • Zahra Shaterian
    • Michał Mrozowski
    2022

    In this paper, the symmetry property of split ring resonators (SRRs) is exploited to develop a tilt sensor. The sensor is composed of an SRR-loaded microstrip line operating at microwave frequencies. It is shown that the depth of notch in the reflection characteristic of the microstrip is a function of the tilt angle of the SRR. Thus, it can be used for sensing inclination. The sensor benefits from very compact size and light weight. Moreover, it is operated at a single frequency, therefore can be used with a simple power meter as the readout circuit. EM simulations show that the proposed sensor exhibits a good average sensitivity of 1 dB/degree while providing a relatively wide span of 25 degrees.

  • A compact spline-enhanced monopole antenna for broadband/multi-band and beyond UWB applications
    • Michał Czyż
    • Jan Olencki
    • Adrian Bekasiewicz
    2022 Pełny tekst AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS

    In this work, a compact monopole antenna for broadband/multi-band and beyond ultra- wideband (UWB) communication has been proposed. The structure is based on a spline-enhanced radiator with a broadband feed and a modified ground plane. Rigorous design optimization of the radiator has been performed in a two-stage framework where optimization of the structure with respect to electrical performance is followed by explicit miniaturization using a constrained objective function. Two compact radiators characterized by footprints of 404 mm 2 and 322 mm 2 , as well as frequency ranges from 2.8 GHz to 34.9 GHz and from 2.9 GHz to 33.9 GHz have been designed. Except for a relatively narrow frequency range in Ka band (from 34.9 GHz to 37.8 GHz), the larger structure is capable of operating for up to 80 GHz. Owing to a simple topology, small size and broadband operation, the presented antennas are of potential use in mobile terminals dedicated to support various wireless technologies including Internet of Things, WiFi, or UWB-based localization services. The proposed radiators have been benchmarked against other broadband/beyond UWB antennas from the literature. Electrical and field characteristics of the proposed structures have been confirmed through measurements of the fabricated prototypes.

  • A Comparative Study of Fuzzy SMC with Adaptive Fuzzy PID for Sensorless Speed Control of Six-Phase Induction Motor
    • Lelisa Wogi
    • Tadele Ayana
    • Marcin Morawiec
    • Andrzej Jąderko
    2022 Pełny tekst ENERGIES

    Multi-phase motors have recently replaced three-phase induction motors in a variety of applications due to the numerous benefits they provide, and the absence of speed sensors promotes induction motors with variable speed drives. Sensorless speed control minimizes unnecessary speed encoder cost, reduces maintenance, and improves the motor drive’s reliability. The performance comparison of the fuzzy sliding mode controller (FSMC) with adaptive fuzzy proportional integral derivative (AFPID) control methods for sensorless speed control of six-phase induction motors was analyzed in this study, and the proposed control system has an advantage for multiphase machines, specifically six-phase induction motors (IMs) in this study, as they are the current active research area for electric vehicles, hybrid electric vehicles, aerospace, ship propulsion, and high-power applications. The speed control of a six-phase induction motor was performed by using an AFPID controller and FSMC. The comparative performance analysis was based on sensorless speed control of the six-phase induction motor. A proportional integral derivative (PID) controller is commonly employed as it is used to eliminate oscillations, but it has several drawbacks, such as taking a long time to decrease the error and stabilize the system at constant speed. The fuzzy type-2 and PID controllers were hybridized so as to obtain the advantages of both to enhance the system performance. Finally, the comparison result revealed that the FSMC preforms significantly better by achieving good tracking performance. The control technique maintains the sliding mode approach’s robustness while providing reduced overshoots with a smooth control action, and the FSMC revealed good dynamic response under load variations when compared to the AFPID controller.

  • A comparative study of organic pollutants in seawater, sediments and oyster tissues at Hab River Delta, Balochistan coast, Pakistan
    • Sadar Aslam
    • Malik Wajid Hussain Chan
    • Grzegorz Boczkaj
    • Ghazala Siddiqui
    2022

    This chapter is about a Comparative Study of Organic Pollutants in Seawater, Sediments, and Oyster Tissues at Hab River Delta, Balochistan Coast, Pakistan.

  • A Comparative Study on Methods of Distinction Between Near- and Far-Side Defects as Techniques Used Alongside with the Magnetic Flux Leakage Testing
    • Zbigniew Usarek
    • Marek Chmielewski
    • Leszek Piotrowski
    2022 Pełny tekst JOURNAL OF NONDESTRUCTIVE EVALUATION

    Results of the finite element analysis show that a far-side defect in a steel plate, with the depth greater by 10% of the plate thickness than a near-side defect, can produce a very similar magnetic flux leakage (MFL) signal. Due to the fact that a measurement of MFL itself can lead to misclassification of a far-side defect as a near-side one, and thus to underestimation of its depth, a comparative study of three complementary magnetic techniques was performed. The following techniques were studied: surface topology air-gap reluctance system (STARS), residual magnetic flux leakage (RMFL) and stray magnetic flux leakage (SMFL). Numerical results showed that in the case of the STARS and SMFL, defect signatures in signals were observed for investigated near-side defects, but not for far-side defects. The signature of the far-side defect in the RMFL was observed, however its peak-to-peak value was only about 8% of the value corresponding to the near-side defect.

  • A comparative study on the decolorization of Tartrazine, Ponceau 4R, and Coomassie Brilliant Blue using persulfate and hydrogen peroxide based Advanced Oxidation Processes combined with Hydrodynamic Cavitation
    • Zahra Askarniya
    • Soroush Baradaran
    • Shirish H. Sonawane
    • Grzegorz Boczkaj
    2022 Pełny tekst CHEMICAL ENGINEERING AND PROCESSING

    Decolorization of Ponceau 4R, Tartrazine, and Coomassie Brilliant Blue (CBB) was studied using hybrid processes of hydrodynamic cavitation (HC) with potassium persulfate (KPS) and hydrogen peroxide (H2O2). The different properties of these dyes such as hydrophobicity, molecular structures, and molecular weights provided this opportunity to investigate the effects of these factors by comparing the decolorization values of the dyes. Treatment process was optimized in respect to cavitation number, HC inlet pressure, and the concentration of external oxidants. The application of dual oxidation system under cavitation conditions revealed a synergetic effect. Maximum decolorization values of 92.27%, 50.1%, and 42.3% were obtained applying this combined process for CBB, Tartrazine, and Ponceau 4R, respectively. The different values of decolorization of the dyes were explained based on their different properties. The kinetic study led to first order rate constants of 10−3 min−1, 6.4*10−3 min−1, 9.2*10−3 min−1, and 4.16*10−2 min−1 using KPS, H2O2, HC, and HC-KPS-H2O2, respectively. A synergetic coefficient of 2.51 obtained by HC-KPS-H2O2 proved the effectiveness of this combined process. Analysis of cavitation yield efficiency showed an improvement of 98% for the HC-KPS-H2O2 combined process as compared to sole HC treatment process.

  • A comprehensive overview of software product management challenges
    • Olga Springer
    • Jakub Miler
    2022 Pełny tekst EMPIRICAL SOFTWARE ENGINEERING

    The principal focus of software product management is to ensure the economic success of the product, which means to prolong the product life as much as possible with modest expenditures to maximizs profits. Software product managers play an important role in the software development organization while being responsible for the strategy, business case, product roadmap, high-level requirements, product deployment (release-management), and retirement plan. This article explores the problems that affect the software product management process, their perceived frequency and perceived severity. The data were collected by a systematic literature review (5 main databases were analyzed), interviews (10 software product managers from IT companies), and surveys (89 participants). 95 software product management problems assigned nonexclusively to 7 areas were identified. 27 commonly mentioned software product management problems were evaluated for their perceived frequency and perceived severity. The problems perceived as the most frequent are: determining the true value of the product that the customer needs, strategy and priorities change frequently, technical debt, working in silos, and balancing between reactive and proactive work. In total, 95 problems have been identified which have been narrowed down to 27 problems based on their occurrence in at least 3 interviews. These selected problems were prioritized by perceived frequency and perceived severity. Some of the identified problems spanned beyond the software product management process itself, but they all affect the work of software product managers.

  • A comprehensive review on current and emerging technologies toward the valorization of bio‐based wastes and by products from foods
    • Roberto Castro‐Muñoz
    • Elsa Díaz‐Montes
    • Emilia Gontarek-Castro
    • Grzegorz Boczkaj
    • Charis M. Galanakis
    2022 COMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY

    Industries in the agro-food sector are the largest generators of waste in the world. Agro-food wastes and by products originate from the natural process of senescence, pretreatment, handling, and manufacturing processes of food and beverage products. Notably, most of the wastes are produced with the transformation of raw materials (such as fruits, vegetables, plants, tubers, cereals, and dairy products) into different processed foods (e.g., jams, sauces, and canned fruits/vegetables), dairy derivatives (e.g., cheese and yogurt), and alcoholic (e.g., wine and beer) and nonalcoholic beverages (e.g., juices and soft drinks). Current research is committed not only to the usage of agro-food wastes and by products as a potential source of high-value bioactive compounds (e.g., phenolic compounds, anthocyanins, and organic acids) but also to the implementation of emerging and innovative technologies that can compete with conventional extraction methods for the efficient extraction of such biomolecules from the residues. Herein, specific valorization technologies, such as membrane-based processes, microwave, ultrasound, pulsed electric-assisted extraction, supercritical/subcritical fluids, and pressurized liquids, have emerged as advanced techniques in extracting various added-value biomolecules, showing multiple advantages (improved extraction yields, reduced process time, and protection to the bioactive properties of the compounds). Hence, this comprehensive review aims to analyze the ongoing research on applying such techniques in valorization protocols. A last-five-year review, together with a featured analysis of the relevant findings in the field, is provided.

  • A comprehensive study on nonlinear hygro-thermo-mechanical analysis of thick functionally graded porous rotating disk based on two quasi three-dimensional theories
    • Shahriar Dastjerdi
    • Yaghoub Tadi Beni
    • Mohammad Malikan
    2022 Pełny tekst MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES

    In this paper, a highly efficient quasi three-dimensional theory has been used to study the nonlinear hygro-thermo-mechanical bending analysis of very thick functionally graded material (FGM) rotating disk in hygro-thermal environment considering the porosity as a structural defect. Two applied quasi three-dimensional displacement fields are assumed in which the strain along the thickness is not zero unlike most of the other plate theories. By considering the nonlinear strains (von Kármán’s assumptions) the large deformations have also been taken into account in order to obtain more accurate results. Finally, some factors that affect the results have been studied further.

  • A Comprehensive Survey on Antennas On-Chip Based on Metamaterial, Metasurface, and Substrate Integrated Waveguide Principles for Millimeter-Waves and Terahertz Integrated Circuits and Systems
    • Mohammad Alibakhshikenari
    • Esraa Mousra Ali
    • Mohammad Soruri
    • Mariana Dalarsson
    • Mohammad Naser-moghadasi
    • Bal S. Virdee
    • Caslav Stefanovic
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    • Stanisław Szczepański
    • Ernesto Limiti
    2022 Pełny tekst IEEE Access

    Antennas on-chip are a particular type of radiating elements valued for their small footprint. They are most commonly integrated in circuit boards to electromagnetically interface free space, which is necessary for wireless communications. Antennas on-chip radiate and receive electromagnetic (EM) energy as any conventional antennas, but what distinguishes them is their miniaturized size. This means they can be integrated inside electronic devices. Although on-chip antennas have a limited range, they are suitable for cell phones, tablet computers, headsets, global positioning system (GPS) devices, and WiFi and WLAN routers. Typically, on-chip antennas are handicapped by narrow bandwidth (less than 10%) and low radiation efficiency. This survey provides an overview of recent techniques and technologies investigated in the literature, to implement high performance on-chip antennas for millimeter-waves (mmWave) and terahertz (THz) integrated-circuit (IC) applications. The technologies discussed here include metamaterial (MTM), metasurface (MTS), and substrate integrated waveguides (SIW). The antenna designs described here are implemented on various substrate layers such as Silicon, Graphene, Polyimide, and GaAs to facilitate integration on ICs. Some of the antennas described here employ innovative excitation mechanisms, for example comprising open-circuited microstrip-line that is electromagnetically coupled to radiating elements through narrow dielectric slots. This excitation mechanism is shown to suppress surface wave propagation and reduce substrate loss. Other techniques described like SIW are shown to significantly attenuate surface waves and minimise loss. Radiation elements based on the MTM and MTS inspired technologies are shown to extend the effective aperture of the antenna without compromising the antenna’s form factor. Moreover, the on-chip antennas designed using the above technologies exhibit significantly improved impedance match, bandwidth, gain and radiation efficiency compared to previously used technologies. These features make such antennas a prime candidate for mmWave and THz on-chip integration. This review provides a thorough reference source for specialist antenna designers.

  • A conceptual framework for digital tax administration - A systematic review
    • Edidiong Bassey
    • Emer Mulligan
    • Adegboyega Ojo
    2022 Pełny tekst GOVERNMENT INFORMATION QUARTERLY

    Tax administrations worldwide have become highly digitised with a diverse and sophisticated array of e-services to enhance the taxpayer experience. Nevertheless, given the high rates of failure of e-government services, it is critical to understand the factors that are essential to the success of a digital tax system. Drawing on a systematic review of ninety-six publications across the digital taxation, taxation, and information systems (IS) literature, a comprehensive conceptual framework is developed to improve our success of digital services in tax administration. The conceptual framework identifies fifteen themes for consideration by policymakers when designing digital services in tax administrations clustered around four categories – Context, Stakeholders, Technology and Demonstrated Results. The framework should also serve as a reference point in successfully developing strategies and measures to embed digital services in tax administrations. Future research directions are also proposed based on the conceptual framework that will help advance our understanding of digital services in tax administration beyond technology acceptance models.

  • A Control Theoretical Approach to Spectral Factorization is Unstable
    • Michał Meller
    • Adam Lasota
    2022 Pełny tekst CIRCUITS SYSTEMS AND SIGNAL PROCESSING

    Local stability analysis of a recently proposed recursive feedback-based approach to spectral factorization is performed. The method is found not to give stability guarantees. Interestingly enough, its global behavior often allows one to obtain reasonable approximations of spectral factorizations if a suitable stopping criterion is employed.

  • A convergence result for mountain pass periodic solutions of perturbed Hamiltonian systems
    • Marek Izydorek
    • Joanna Janczewska
    • Pedro Soares
    2022 Pełny tekst COMMUNICATIONS IN CONTEMPORARY MATHEMATICS

    In this work, we study second-order Hamiltonian systems under small perturbations. We assume that the main term of the system has a mountain pass structure, but do not suppose any condition on the perturbation. We prove the existence of a periodic solution. Moreover, we show that periodic solutions of perturbed systems converge to periodic solutions of the unperturbed systems if the perturbation tends to zero. The assumption on the potential that guarantees the mountain pass geometry of the corresponding action functional is of independent interest as it is more general than those by Rabinowitz [Homoclinic orbits for a class of Hamiltonian systems, Proc. R. Soc. Edinburgh A 114 (1990) 33–38] and the authors [M. Izydorek and J. Janczewska, Homoclinic solutions for a class of the second-order Hamiltonian systems, J. Differ. Equ. 219 (2005) 375–389].

  • A Cost-Effective Method for Reconstructing City-Building 3D Models from Sparse Lidar Point Clouds
    • Marek Kulawiak
    2022 Pełny tekst Remote Sensing

    The recent popularization of airborne lidar scanners has provided a steady source of point cloud datasets containing the altitudes of bare earth surface and vegetation features as well as man-made structures. In contrast to terrestrial lidar, which produces dense point clouds of small areas, airborne laser sensors usually deliver sparse datasets that cover large municipalities. The latter are very useful in constructing digital representations of cities; however, reconstructing 3D building shapes from a sparse point cloud is a time-consuming process because automatic shape reconstruction methods work best with dense point clouds and usually cannot be applied for this purpose. Moreover, existing methods dedicated to reconstructing simplified 3D buildings from sparse point clouds are optimized for detecting simple building shapes, and they exhibit problems when dealing with more complex structures such as towers, spires, and large ornamental features, which are commonly found e.g., in buildings from the renaissance era. In the above context, this paper proposes a novel method of reconstructing 3D building shapes from sparse point clouds. The proposed algorithm has been optimized to work with incomplete point cloud data in order to provide a cost-effective way of generating representative 3D city models. The algorithm has been tested on lidar point clouds representing buildings in the city of Gdansk, Poland.

  • A Cross-Polarisation Discrimination Analysis of Off-Body Channels in Passenger Ferryboat Environments
    • Sławomir Ambroziak
    • Krzysztof Cwalina
    • Piotr Rajchowski
    • Filipe D. Cardoso
    • Manuel M. Ferreira
    • Luis M. Correia
    2022 Pełny tekst IEEE Access

    There is a need for investigating radio channels for Body Area Networks considering the depolarisation phenomenon and new types of environments, since these aspects are becoming very important for systems design and deployment. This paper presents an analysis of cross-polarisation discrimination for off-body channels based on a measurement campaign performed in a passenger ferryboat, i.e., where all walls, floors and ceilings are made of metal. Firstly, the measurement campaign, including test-bench and scenarios, as well as the analysis approach, including classification of mutual antennas’ orientation and definition of parameters are described. The analysis of results includes distance, on-body antennas location and several scenarios, addressing statistical parameters. Mean values for the cross-polarisation discrimination are in the range of [3.7, 6.8] dB while the standard deviation is around 10.0 dB. There is no dependence of the cross-polarisation discrimination on distance, within the measured range (up to 16 m). It is found that there is no correlation between radio signals received by vertically and horizontally polarised receiving antennas, hence, enabling the application of polarisation diversity in Body Area Networks. The Normal Distribution is the best fit for describing cross-polarisation discrimination, as shown by the analysis of goodness of fit parameters, since it passes many of the tests.

  • A Direct Modulation for Matrix Converters based on the Onecycle Atomic operation developed in Verilog HDL.
    • Paweł Szczepankowski
    • Wojciech Śleszyński
    • Tomasz Bajdecki
    2022 Pełny tekst IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS

    This paper presents a fast direct Pulse Width Modulation (PWM) algorithm for the Conventional Matrix Converters (CMC) developed in Verilog Hardware Description language (HDL). All PWM duty cycle calculations are performed in one cycle by an atomic operation designed as a digital module using FPGA basic blocks. The algorithm can be extended to any number of output phase. The improved version of the discontinuous Direct Analytic Voltage PWM (DAV–PWM) method is proposed, in which the use of trigonometry, angles and program loops has been eliminated. The proposed DAV-PWM is equivalent to the Space Vector Modulation (SVM), it can be applied during input asymmetry and also allows for the control of the displacement input angle. The proposal has been verified using the circuit simulation in PSIM, digital structure modelling in ModelSim, and finally through an experiment.

  • A dual-control strategy based on electrode material and electrolyte optimization to construct an asymmetric supercapacitor with high energy density
    • Xianyu Chu
    • Fanling Meng
    • Wei Zhang
    • He Yang
    • Xu Zou
    • Sebastian Molin
    • Piotr Jasiński
    • Xiangcheng Sun
    • Weitao Zheng
    2022 NANOTECHNOLOGY

    Metal-organic frames (MOFs) are regarded as excellent candidates for supercapacitors that have attracted much attention because of their diversity, adjustability and porosity. However, both poor structural stability in aqueous alkaline electrolytes and the low electrical conductivity of MOF materials constrain their practical implementation in supercapacitors. In this study, bimetallic CoNi-MOF were synthesized to enhance the electrical conductivity and electrochemical activity of nickel-based MOF, as well as the electrochemical performance of the CoNi-MOF in multiple alkaline electrolytes was investigated. The CoNi-MOF/active carbon device, as-fabricated with a 1 M KOH electrolyte, possesses a high energy density of 35 W h kg−1 with a power density of 1450 W kg−1, exhibiting outstanding cycling stability of 95% over 10,000 cycles. The design of MOF-based electrode materials and the optimization selection of electrolytes pave the way for constructing high-performance supercapacitors.

  • A Dual-Polarized 39 GHz 4x4 Microstrip Antenna Array for 5G MU-MIMO Airflight Cabin Connectivity
    • Kamil Trzebiatowski
    • Jan Fromme
    • Damian Duraj
    • Łukasz Kulas
    • Krzysztof Nyka
    2022 Pełny tekst

    This paper presents the design, fabrication, and experimental validation of a 39 GHz dual-polarized 4x4 microstrip antenna array. The array consists of 16 slot coupled circular microstrip patches, fed through SMPS connectors. The procedure requiring a reduced number of cables for measurement of the uniformly excited antenna array is also presented. The array exhibits 18 dBi peak gain and 2.9 GHz reflection bandwidth and is intended for use in a 5G base station inside an airplane. The presented antenna is characterized by a simple feeding system which results in a reduced number of via-holes and dielectric layers.

  • A facile approach to fabricate load-bearing porous polymer scaffolds for bone tissue engineering
    • Tairong Kuang
    • Shaowei Chen
    • Zhipeng Gu
    • Zhisen Shen
    • Aleksander Hejna
    • Mohammad Saeb
    • Feng Chen
    • Mingqiang Zhong
    • Tong Liu
    2022 Advanced Composites and Hybrid Materials

    Biodegradable porous scaffolds with oriented interconnected pores and high mechanical are load-bearing biomaterials for bone tissue engineering. Herein, we report a simple, non-toxic, and cost-effective method to fabricate high-strength porous biodegradable scaffolds, composed of a polymer matrix of polycaprolactone (PCL) and water-soluble poly (ethylene oxide) (PEO) as a sacrificial material by integrating annealing treatment, pressure-induced flow (PIF) processing and particulate leaching techniques. The microstructure, crystal orientation, and crystallization behavior were studied by scanning electron microscope (SEM), 2D X-ray techniques, and differential scanning calorimetry (DSC). Through the analysis of SEM and 2D X-ray results, the proposed hybrid strategy aided formation of porous PCL scaffolds with highly oriented pore structures as well as suitable pore size and pore connectivity. Owing to the improvement of crystal orientation and crystallinity after PIF processing, the obtained scaffolds exhibited higher tensile strength (14.1 MPa), compressive strength (6.6 MPa), bending strength (5.9 MPa), and elongation at break (above 150%) compared with the non-oriented porous scaffolds. In addition, NIH-3T3 fibroblast cell culture unveiled in vitro biocompatibility of the scaffolds. Overall, the obtained oriented porous PCL scaffolds exhibited good biocompatibility, elongated cell morphology, and highly strengthened oriented structure for load-bearing bone tissue applications.

  • A facile method for Tauc exponent and corresponding electronic transitions determination in semiconductors directly from UV–Vis spectroscopy data
    • Łukasz Haryński
    • Adrian Olejnik
    • Katarzyna Grochowska
    • Katarzyna Siuzdak
    2022 OPTICAL MATERIALS

    In this work, a facile method allowing for estimation of the exponent in the Tauc equation directly from the UV–vis spectra is presented. It is based on the Taylor expansion of the logarithmic version of the Tauc equation. The Tauc exponent is calculated from the tangent slope of the absorption data. Knowledge of this coefficient provides information about the optical transition types and is used as an input for the calculations of the band gap. As an exemplar material, TiO2 in form of thin film and nanotubes as well as their nanocomposites with other metal oxides are chosen. For the transparent thin 15 nm film of TiO2, two linear ranges with n = 2.0 and 1.2 are found. The first is assigned to the well-established indirect (allowed) transition. In the case of the second one, the n does not correspond to typically used values. Therefore, it is speculated that more than one transition is probable. This consideration is supported with ab-initio DFT calculations of the band structure of TiO2 with Hubbard U correction. Similar results are found for TiO2 nanotubes using diffuse reflectance spectroscopy indicating that the presented method applies both to transmission and reflection.

  • A facile structural manipulation strategy to prepare ultra-strong, super-tough, and thermally stable polylactide/nucleating agent composites
    • Tairong Kuang
    • Jiajun Ju
    • Tong Liu
    • Aleksander Hejna
    • Mohammad Saeb
    • Shuidong Zhang
    • Xiangfang Peng
    2022 Advanced Composites and Hybrid Materials

    Polylactide (PLA) is a biodegradable thermoplastic widely used in diferent felds, but it should be adequately modifed considering high-performance applications. However, the current processes for developing PLA materials achieve high strength at the expense of toughness or ductility of the materials. Therefore, there is need to develop new strategies for generation of PLA materials with high strength, great toughness, good ductility, and high heat resistance. The present study reported a facile and cost-efective structural manipulation strategy for fabricating high-performance PLA composites that involved addition of 0.5 wt% self-assembled nucleation agent (TMC-306). During the structural manipulation process, the nucleation agent (TMC-306 shish) initially induced the PLA materials to develop a random shish-kebab crystal structure. A chain-like interlocking shish-kebab crystal structure with gradients in both length and thickness was then achieved through semi-solid high-pressure molding. The resulting super-PLA product showed excellent tensile strength (98.7 MPa), superb toughness (82.7 kJ/m2 ), and high elongation at break (117.5%). The reported qualities of the super-PLA materials were superior to that of most commercially available commodity polymers and were comparable to engineering plastics. In addition, PLA composites exhibited a lower thermal deformation variable and a higher Vicat softening temperature (112.4 °C) than neat PLA (62.1 °C). The facile strategy reported in the present study allows development of strong, tough, ductile, and thermally stable PLA, making it a potential alternative plastic material to commodity and engineering plastics used in many technical felds.

  • A finite element analysis of thermal energy inclination based on ternary hybrid nanoparticles influenced by induced magnetic field
    • Muhammad Bilal Hafeez
    • Marek Krawczuk
    • Sooppy Nisar Kottakkaran
    • Wasim Jamshed
    • Amjad Ali Pasha
    2022 Pełny tekst INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER

    The use of hybrid nanoparticles to improve thermal processes is a key method that has implications for a variety of interventions utilized in many sectors. This paper aimed to look into the impacts of ternary nanoparticles on hyperbolic tangent materials to establish their thermal characteristics. Flow describing equations have been explored in the presence of heat production, non-Fourier heat flux, and an induced magnetic field. Boundary layer analysis, which generates partial differential equations, was used to model the physical situation under several major physical properties (PDEs). The flow rheology is expanded and calculated in a rotating frame by supposing that the flow is created by a spinning disk. The solution of complicated generated PDEs was calculated using the Galerkin finite element technique (G-FEM) after translating them into corresponding ODEs. Several major bodily repercussions have been seen and documented because of increasing the implicated influencing factors.

  • A framework for onboard assessment and monitoring of flooding risk due to open watertight doors for passenger ships
    • Pekka Ruponen
    • Jakub Montewka
    • Markus Tompuri
    • Teemu Manderbacka
    • Spyros Hirdaris
    2022 Pełny tekst RELIABILITY ENGINEERING & SYSTEM SAFETY

    Post-accident safety of ships is governed by damage stability, affected by watertight subdivisions which limit accidental flooding. This is important for passenger ships with watertight doors (WTDs) often fitted in the bulkheads. Awareness of the ship flooding risk due to open WTDs and the conditions under which the associated risk level changes are prerequisites for proactive risk mitigation. Accident risk is often expressed as a combination of accident likelihood and its consequences. Current solu-tions for flooding risk mitigation often treat these elements separately, or the adopted metrics are based on quantities not allowing proper active control of risk. In this paper an attempt is made to fill this gap by introducing a novel concept for rapidly assessing the flooding risk onboard passenger ships, accounting for the two dimensions of flooding accidents. The likelihood part is based on the complexity of surrounding traffic, operational conditions, and human reliability assessment. The consequences are based on precalculated probabilistic damage stability results of ship survivability. The presented case studies indicate that active monitoring of flooding risk can increase the crew’s situational awareness of the effect of open WTDs on the flooding risk, thus positively influencing the safety culture onboard the ship.

  • A general isogeometric finite element formulation for rotation‐free shells with in‐plane bending of embedded fibers
    • Thang X. Duong
    • Mikhail Itskov
    • Roger Sauer
    2022 Pełny tekst INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING

    This article presents a general, nonlinear isogeometric finite element formulation for rotation-free shells with embedded fibers that captures anisotropy in stretching, shearing, twisting, and bending - both in-plane and out-of-plane. These capabilities allow for the simulation of large sheets of heterogeneous and fibrous materials either with or without matrix, such as textiles, composites, and pantographic structures. The work is a computational extension of our earlier theoretical work that extends existing Kirchhoff-Love shell theory to incorporate the in-plane bending resistance of initially straight or curved fibers. The formulation requires only displacement degrees-of-freedom to capture all mentioned modes of deformation. To this end, isogeometric shape functions are used in order to satisfy the required C1-continuity for bending across element boundaries. The proposed formulation can admit a wide range of material models, such as surface hyperelasticity that does not require any explicit thickness integration. To deal with possible material instability due to fiber compression, a stabilization scheme is added. Several benchmark examples are used to demonstrate the robustness and accuracy of the proposed computational formulation.

  • A general theory for anisotropic Kirchhoff–Love shells with in-plane bending of embedded fibers
    • Thang X. Duong
    • Vu N Khiêm
    • Mikhail Itskov
    • Roger Sauer
    2022 Pełny tekst MATHEMATICS AND MECHANICS OF SOLIDS

    This work presents a generalized Kirchhoff–Love shell theory that can explicitly capture fiber-induced anisotropy not only in stretching and out-of-plane bending, but also in in-plane bending. This setup is particularly suitable for heterogeneous and fibrous materials such as textiles, biomaterials, composites and pantographic structures. The presented theory is a direct extension of classical Kirchhoff–Love shell theory to incorporate the in-plane bending resistance of fibers. It also extends existing second-gradient Kirchhoff–Love shell theory for initially straight fibers to initially curved fibers. To describe the additional kinematics of multiple fiber families, a so-called in-plane curvature tensor—which is symmetric and of second order—is proposed. The effective stress tensor and the in-plane and out-of-plane moment tensors are then identified from the mechanical power balance. These tensors are all second order and symmetric in general. Constitutive equations for hyperelastic materials are derived from different expressions of the mechanical power balance. The weak form is also presented as it is required for computational shell formulations based on rotation-free finite element discretizations. The proposed theory is illustrated by several analytical examples.

  • A hierarchical porous composite magnetic sorbent of reduced graphene oxide embedded in polyvinyl alcohol cryogel for solvent‐assisted‐solid phase extraction of polycyclic aromatic hydrocarbons
    • Natnaree Rattanakunsong
    • Sirintorn Jullakan
    • Justyna Płotka-Wasylka
    • Opas Bunkoed
    2022 Pełny tekst JOURNAL OF SEPARATION SCIENCE

    A hierarchical porouscomposite magnetic sorbent was fabricated and applied tothe dispersive solvent-assisted solid-phase extraction of five polycyclic aromatichydrocarbons. A sorbent was first prepared by incorporating graphene oxide,calcium carbonate, and magnetite nanoparticles into a polyvinyl alcohol cryo-gel. The graphene oxide was converted to reduced graphene oxide using ascorbicacid and a hierarchical porous structure was produced by reacting hydrochlo-ric acid with incorporated calcium carbonate to generate carbon dioxide bubbleswhichcreatedasecondnetwork.Beforeextractingthetargetanalytes,theextrac-tion solvent was introduced into the hierarchical pore network of the sorbent.The extraction was based on the partition between the analytes and introducedextraction solvent and the adsorption of analytes on reduced graphene oxide.Theextraction efficiency was enhanced through π-π and hydrophobic interactionsbetween polycyclic aromatic hydrocarbons and reduced graphene oxide andextraction solvent. The extracted polycyclic aromatic hydrocarbons were deter-mined by using high-performance liquid chromatography coupled with a fluo-rescence detector. The developed method was applied to extract polycyclic aro-matic hydrocarbons in disposable diaper, coffee, and tea samples and recoveriesfrom 84.5 to 99.4% were achieved with relative standard deviations below 7%.The developed sorbent exhibited good reproducibility and could be reused for 10cycles.The developed sorbent exhibited good reproducibility and could be reusedfor 10 cycles.The developed sorbent exhibited good reproducibility and could bereused for 10 cycles.

  • A method for a comprehensive lipidomic analysis of flaxseed (Linum usitatissimum) with the use of LC–Q-TOF-MS and dispersive micro-solid-phase (μDSPE) extraction
    • Inal Bakhytkyzy
    • Weronika Hewelt-Belka
    • Agata Kot-Wasik
    2022 FOOD CHEMISTRY

    Flaxseed (FS) is one of the richest sources of α-linolenic acid oil and lignans, and it is suggested that the consumption of flaxseed may contribute to the prevention of certain chronic diseases such as many types of cancer, diabetes, cardiovascular diseases and cerebrovascular stroke. Here, we demonstrate a new method for comprehensive FS lipidome profiling with the use of LC–Q-TOF-MS and dispersive micro-solid-phase extraction. The effects of stationary phase amount, flaxseed amount and different organic solvents for non-polar lipid elution on the FS lipidome coverage were investigated. The developed and validated protocol allowed for improved monitoring of both polar and non-polar lipids simultaneously, overcoming the challenge of low- and high-abundance lipid species. Furthermore, the method was applied to characterize a set of brown flaxseed and yellow flaxseed samples, as well as flaxseed meal.

  • A method for the analysis of methylmercury and total Hg in fungal matrices
    • Małgorzata Rutkowska
    • Jerzy Falandysz
    • Martyna Saba
    • Piotr Szefer
    • Małgorzata Misztal-Szkudlińska
    • Piotr Konieczka
    2022 Pełny tekst APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

    The aim of the study was to develop an efficient method for the determination of monomethyl-mercury (MeHg) and total mercury (THg) content in materials such as fungal sporocarps and sclerotia. Certified Reference Materials (CRMs) with the assigned values of MeHg and THg as well as the control materials (dried mushrooms) with known content of THg were evaluated for method validation. Recovery of MeHg from reference materials was at the following levels: from tuna fish at 87.0 ± 2.3% (THg at 101.9 ± 1.2%), from fish protein at 99.4 ± 1.3% (THg at 92.70 ± 0.41%), and from dogfish liver at 96.45 ± 0.73%. Recovery of THg from the fungal control material CS-M-5 was at 104.01 ± 0.60% (contribution of MeHg in THg content was at 6.2%), from CS-M-4 at 101.1 ± 2.0% (contribution at 3.2%), from CS-M-3 at 100.55 ± 0.67% (contribution at 0.6%), and from CS-M-2 at 101.5 ± 2.7% (contribution at 3.7%). The content of MeHg in randomly selected wild fungi and their morphological parts was in the range from 0.006 to 0.173 mg kg−1 dry weight (dw). In the case of THg, the concentration values were in the range from 0.0108 to 10.27 mg kg−1 dw. The MeHg content in the control materials with the assigned THg values was determined. Since the control materials play an important role in all elements of the quality assurance system of measurement results, they can be used to analyse MeHg as the first control material for fungi.

  • A model of damaged media used for describing the process of non-stationary creep and long-term strength of polycrystalline structural alloys
    • Leonid A. Igumnov
    • Ivan Volkov
    • Evgeny Boev
    • Victor Eremeev
    2022 Pełny tekst CONTINUUM MECHANICS AND THERMODYNAMICS

    The main laws of the processes of creep and long-term strength of polycrystalline structural alloys are considered. From the viewpoint of continuum damaged media (CDM), a mathematical model is developed that describes the processes of viscoplastic deformation and damage accumulation under creep. The problem of determining material parameters and scalar functions of the developed constitutive relations based on the results of specially set basic experiments is discussed. An experimental–theoretical methodology for determining material parameters of the derived constitutive relations of CDM is developed based on analyzing the viscoplastic deformation and failure processes of laboratory specimens in the conditions of soft loading (stress controlled). Experimental results of short-term creep of the VZh-159 heat-resistant alloy are presented. The obtained numerical results are compared with the test data using the numerical modeling method of experimental processes. Qualitative and quantitative agreement between numerical results and experimental data is shown. It is concluded that the developed constitutive relations are reliable, and that the proposed methodology accurately determines the material parameters of the model under degradation of initial strength properties of structural materials according to the long-term strength mechanism.

  • A model of the response of the MGS-6 gravity sensor to tilting
    • Krzysztof Pyrchla
    • Małgorzata Pająk
    • Julia Gołyga
    • Jerzy Pyrchla
    2022 Pełny tekst MEASUREMENT

    The reliable interpretation of the measurements made by the Micro-g marine gravimetric system (MGS-6) depends on how the temporary changes of the scale coefficients such as gravimeter scale factor, vertical cross-coupling (VCC) effect, tiltmeter cross and tiltmeter long are compensated for during the signal analysis. The listed coefficients cannot be determined from readings during the measurements or by analysing the final data. The method presented here can be used to periodically check individual scale factors before starting shipborne measurements. This article focuses on determining the scale coefficients of the gravimeter: VCC effect, tiltmeter cross and tiltmeter long based on the MGS-6 gravity sensor's response to tilt. An unique non-linear model of Lacoste&Romberg gravimeter response to tilt was developed. In this paper, the measurement of the tilt angle of the object based on the photogrammetric elaboration of metric photographs is presented, using the principles of one-image photogrammetry.

  • A natural deep eutectic solvent - protonated L-proline-xylitol - based stationary phase for gas chromatography
    • Malwina Momotko
    • Justyna Łuczak
    • Andrzej Przyjazny
    • Grzegorz Boczkaj
    2022 Pełny tekst JOURNAL OF CHROMATOGRAPHY A

    The paper presents a new kind of stationary phase for gas chromatography based on deep eutectic solvents (DES) in the form of a mixture of L-proline (protonated with hydrochloric acid) as a hydrogen bond acceptor (HBA) and xylitol as a hydrogen bond donor (HBD) in a molar ratio of HBA:HBD 5:1. DES immobilized on a silanized chromatographic support was tested by gas chromatography (GC) in order to determine its resolving power for volatile organic compounds. Studies have demonstrated the suitability of this type of DES as a stationary phase for GC. The Rohrschneider-McReynolds constants were determined for the synthesized DES, revealing that it is a polar stationary phase (Σ(ΔI) = 1717). The selectivity of DES is influenced by the presence of hydroxyl groups in the xylitol structure capable of forming hydrogen bonds of a donor nature and the proton acceptor properties of the protonated L-proline structure. The presence of additional interactions is brought about by the presence of the carboxyl group. As a result, the retention of alcohols is several times higher (200-670%) than the expected value based on their boiling points. A significant increase in retention (400-970%) was also found for pyridine derivatives. The developed DES stationary phase is characterized by very good repeatability of retention and stability (up to 140°C). The efficiency of the prepared columns (6300-11300 theoretical plates/m) and the selectivity of the DES stationary phase are competitive with the commercial products.

  • A New Approach to Assess Quality of Motion in Functional Task of Upper Limb in Duchenne Muscular Dystrophy
    • Wiktoria Wojnicz
    • Agnieszka Sobierajska-Rek
    • Bartłomiej Zagrodny
    • Michał Ludwicki
    • Joanna Jabłońska-Brudło
    • Katarzyna Forysiak
    2022 Pełny tekst Applied Sciences-Basel

    (1) Background: This study presents a new method for the motion quantitative analysis of Duchenne muscular dystrophy patients (DMD) performing functional tasks in clinical conditions. (2) Methods: An experimental study was designed to define how different levels of external mass (light and heavy) influence the performance of the upper limbs of a tested DMD and reference subject (RS) during horizontal movements (level of the waist) under natural conditions (NC) and passive manipulator conditions (PMC); the kinematic data and muscle activity of four chosen superficial muscles (EMG) were recorded. (3) Results: A piecewise linear multi-regression analysis revealed high statistically significant results (R2 ≥ 0.75) between the tested muscle activities and kinematic data in the tested DMD patient and RS. These results were used to define whether the neural control of the four tested muscles (processed EMG data) was correlated more with the displacement of the wrist joint or the center of mass of the tested upper limb while performing functional tests with a given external weight in a horizontal plane under NC or PMC. (4) Conclusions: The proposed approach can be used to estimate the contributions of the tested muscles to patients’ motion performance and define whether this contribution is correlated with the kinematics or dynamics of the tested arm

  • A New Critical Risk on the Block: Cyber Risks as an Example of Technical Knowledge Risks in Organizations
    • Małgorzata Zięba
    • Susanne Durst
    • Martyna Gonsiorowska
    2022 Pełny tekst

    The breakout of the COVID-19 pandemic has intensified the appearance of many additional technical knowledge risks in organizations. Cyber risks in particular are becoming a great challenge for organizations. At the same time, academic research on cyber risks, their costs, consequences and ability of overcoming them is still scarce and fragmented. In order to fill this gap, the paper is aimed to identify different types of cyber risks that organizations face and to examine the organizations’ ability to handle those risks. The paper presents research results from a sample of 60 organizations, addressing questions such as: (i) What are the costs of cyber risks the organization has faced? (ii) What is the company ability to address these risks?, and (iii) What is the organization doing to minimize the impact of such risks? Data was collected by means of a questionnaire. This research study has allowed to identify the state of the art concerning cyber risks, which can bear severe consequences for organizations. The findings clearly show that not all organizations suffer from the same level of cyber risks but it is much related to their field of operations. Consequently, also the ability to manage these cyber risks is quite diversified among the examined companies. Research results are limited to a sample of 60 organizations and thus the findings should be taken with caution. The study provides useful insights for managers and owners of organizations in need of dealing with the cyber threats/attacks and other technical knowledge risks threatening their organizations. The paper is enriched with a number of sample solutions that they may apply to mitigate those risks.The paper lays the ground for a better understanding of technical knowledge risks, primarily cyber risks, to which organizations are increasingly exposed today. As such, the paper offers food for thought for researchers dealing with the topic of technical knowledge risks and organizational risk management in general.

  • A New Expression System Based on Psychrotolerant Debaryomyces macquariensis Yeast and Its Application to the Production of Cold-Active β-D-Galactosidase from Paracoccus sp. 32d
    • Marta Wanarska
    • Ewelina Krajewska-Przybyszewska
    • Monika Wicka-Grochocka
    • Hubert Cieśliński
    • Anna Pawlak-Szukalska
    • Aneta Białkowska
    • Marianna Turkiewicz
    • Tomasz Florczak
    • Ewa Gromek
    • Joanna Krysiak
    • Natalia Filipowicz
    2022 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Yeasts provide attractive host/vector systems for heterologous gene expression. The currently used yeast-based expression platforms include mesophilic and thermotolerant species. A eukaryotic expression system working at low temperatures could be particularly useful for the production of thermolabile proteins and proteins that tend to form insoluble aggregates. For this purpose, an expression system based on an Antarctic psychrotolerant yeast Debaryomyces macquariensis strain D50 that is capable of growing at temperatures ranging from 0 to 30 ◦C has been developed. The optimal physical culture conditions for D. macquariensis D50 in a fermenter are as follows: temperature 20 ◦C, pH 5.5, aeration rate of 1.5 vvm, and a stirring speed of 300 rpm. Four integrative plasmid vectors equipped with an expression cassette containing the constitutive GAP promoter and CYC1 transcriptional terminator from D. macquariensis D50 were constructed and used to clone and express a gene-encoding cold-active β-D-galactosidase of Paracoccus sp. 32d. The yield was 1150 U/L of recombinant yeast culture. Recombinant D. macquariensis D50 strains were mitotically stable under both selective and non-selective conditions. The D. macquariensis D50 host/vector system has been successfully utilized for the synthesis of heterologous thermolabile protein, and it can be an alternative to other microbial expression systems.

  • A new factor LapD is required for the regulation of LpxC amounts and lipopolysaccharide trafficking
    • Alicja Wieczorek
    • Anna Sendobra
    • Akshay M S
    • Magdalena Sugalska
    • Gracjana Klein-Raina
    • Satish Raina
    2022 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Lipopolysaccharide (LPS) constitutes the major component of the outer membrane and is essential for bacteria, such as Escherichia coli. Recent work has revealed the essential roles of LapB and LapC proteins in regulating LPS amounts; although, if any additional partners are involved is unknown. Examination of proteins co-purifying with LapB identified LapD as a new partner. The purification of LapD reveals that it forms a complex with several proteins involved in LPS and phospholipid biosynthesis, including FtsH-LapA/B and Fab enzymes. Loss of LapD causes a reduction in LpxC amounts and vancomycin sensitivity, which can be restored by mutations that stabilize LpxC (mutations in lapB, ftsH and lpxC genes), revealing that LapD acts upstream of LapB-FtsH in regulating LpxC amounts. Interestingly, LapD absence results in the substantial retention of LPS in the inner membranes and synthetic lethality when either the lauroyl or the myristoyl acyl transferase is absent, which can be overcome by single-amino acid suppressor mutations in LPS flippase MsbA, suggesting LPS translocation defects in ΔlapD bacteria. Several genes whose products are involved in cell envelope homeostasis, including clsA, waaC, tig and micA, become essential in LapD’s absence. Furthermore, the overproduction of acyl carrier protein AcpP or transcriptional factors DksA, SrrA can overcome certain defects of the LapD-lacking strain.

  • A new method of wind farm active power curve estimation based on statistical approach
    • Natalia Szewczuk-Krypa
    • Piotr Kolendo
    • Jakub Głuszek
    • Mateusz Drop
    • Jacek Aronowski
    2022 Pełny tekst Przegląd Elektrotechniczny

    The purpose of this paper is to solve the wind farm active power estimation problem, introducing the method which is based on a statistical approach and robust fitting. The proposed algorithm uses a statistical approach and compared to existing ones- includes a wind direction as well as the influence of turbine start-up procedure on the estimation. The results show that additional estimation inputs i.e. the wind direction and the turbine state, improve the accuracy of estimated power. Estimation root mean square error captured over three days never exceeded 2%

  • A new model of fuel spray shape at early stage of injection in a marine Diesel engine
    • Joanna Grochowalska
    • Piotr Jaworski
    • Łuaksz Jan Kapusta
    • Jerzy Kowalski
    2022 Pełny tekst INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW

    In the cylinders of a marine diesel engine, self-ignition occurs in very shortly time after the fuel injection into the combustion chamber. Therefore, the paper present was to develop a model of diesel fuel spray for the early stage of fuel spray for in marine diesel engine. There were taken into consideration the main aspects technical such as nozzle diameter of marine engine injector and backpressure in combustion chamber. In this work, laboratory experimental studies were carried out in order to determined parameters of fuel spray in early stage of injection in marine diesel engine. Optical measuring Mie scattering technique was used to record the fuel injection process. The working space was a constant volume chamber. The backpressure parameters in the constant volume chamber were the same as during the operation of the marine diesel engine. On the based on the experimental studies and important Hiroyasu and Arai models of fuel spray presented in literature was proposed new model of fuel spray parameters for marine diesel injector. In this work, proposed new model of the two main parameters described fuel spray evolution: new model of spray tip penetration and spray cone angle. New model propagation of fuel spray tip penetration in time was included the influenced of nozzle diameter and backpressure. The proposed model has a lower error, about 15%-34%, than the model of Hiroyasu and Arai. Moreover a new model of the evolution over time of the spray cone angle is developed. In the future research of fuel spray process must be taken influence of the fuel temperature. Diesel fuel has a different density and viscosity in dependence of fuel temperature. Therefore are predicted of the expansion about influence of fuel temperature, new model of fuel spray for a marine diesel engine. The main limitations occuring in the research are is it not possible to carry out the research while real operation marine diesel engine. Experimental test were carried out for a real fuel injector of a marine diesel engine. Design parameters and fuel injection parameters were selected on the basis of the actual one. In the literature, spray cone angle is defined as constant parameter for the specific preliminary data. A new model for the early stage of fuel spray of spray cone angle propagation in time has beed proposed. The early stage of fuel spray is especially important, because in this time comes in there to fuel self-ignition.