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Gdańsk University of Technology

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  • MANDARIN PEEL AS AN AUSPICIOUS FUNCTIONAL FILLER FOR POLYMER COMPOSITES
    • Aleksander Hejna
    • Mateusz Barczewski
    • Paulina Kosmela
    • Joanna Aniśko
    • Olga Mysiukiewicz
    • Mariusz Marć
    2021 Full text Macedonian Journal of Chemistry and Chemical Engineering

    This work describes the application of mandarin peel (MP) as a waste filler for high-density polyethylene (HDPE) composites. The main goal was to investigate the impact of the filler's essential oils, which include multiple terpenes and terpenoids, on the processing, physicochemical, mechanical, and thermal properties of the composites as a function of different filler content (1 – 10 wt%), as well as its effect on the color and volatile organic compounds emissions of the composites. At small loadings, MP can be considered an efficient filler for wood-polymer composites, enhancing their flowability, tensile strength, and thermal stability. In addition, it may act as a colorant and aroma compound for polymer materials, and can enhance the thermooxidative resistance of composites. The oxidation induction time was increased from 20 min for HDPE up to 62 min for the composites with 10 wt% filler. The research results demonstrate the application of MP not only in the production of highly-filled composites, but also as an additive that significantly enhances the performance of composites at low concentrations.

  • Manganese–Cobalt Based Spinel Coatings Processed by Electrophoretic Deposition Method: The Influence of Sintering on Degradation Issues of Solid Oxide Cell Oxygen Electrodes at 750 °C
    • Elisa Zanchi
    • Justyna Ignaczak
    • Bartosz Kamecki
    • Piotr Jasiński
    • Sebastian Molin
    • A Boccaccini
    • Federico Smeacetto
    2021 Full text Materials

    This paper seeks to examine how the Mn–Co spinel interconnect coating microstructure can influence Cr contamination in an oxygen electrode of intermediate temperature solid oxide cells, at an operating temperature of 750 °C. A Mn–Co spinel coating is processed on Crofer 22 APU substrates by electrophoretic deposition, and subsequently sintered, following both the one-step and two-step sintering, in order to obtain significantly different densification levels. The electrochemical characterization is performed on anode-supported cells with an LSCF cathode. The cells were aged prior to the electrochemical characterization in contact with the spinel-coated Crofer 22 APU at 750 °C for 250 h. Current–voltage and impedance spectra of the cells were measured after the exposure with the interconnect. Post-mortem analysis of the interconnect and the cell was carried out, in order to assess the Cr retention capability of coatings with different microstructures.

  • Manufacturing and Recycling Impact on Environmental Life Cycle Assessment of Innovative Wind Power Plant Part 1/2
    • Krzysztof Doerffer
    • Patrycja Bałdowska-Witos
    • Michał Pysz
    • Piotr Doerffer
    • Andrzej Tomporowski
    2021 Full text Materials

    Wind power plants are considered as ecologically-clean source of energy. However, manufacturing processes cannot be treated that way. Manufacturing processes consume huge amount of electrical and thermal energy and significant amount of materials, e.g. steel, polymers, oils and lubricants. All of the above could be potentially harmful for environment. There are not many works and publications regarding life-cycle analysis of wind power plants. This study objective is to use LCA to the manufacturing and utilization of a specific drag force driven wind turbine. The discussed innovative wind turbine is of the type which assures safety for prosumer application. Drag force driven turbines become more heavy than other types of lift driven turbines but in the same time their characteristic provides opportunity to use easily recyclable materials instead of materials like plastics or composites. The wider look through LCA tools, may change the perspective of view at that type of wind turbines.. Analyzed turbine has capacity of 15 kW and is located in Poland. LCA was carried out using Eco-indicator 99 method in eleven impact categories. Among all of the turbine components the highest negative impact was noted in the case of the tower. Wind turbine under consideration is characterized by high recycling potential. According to presented research recycling provides around 30% reduction of environmental impact.

  • Manufacturing and Recycling Impact on Environmental Life Cycle Assessment of Innovative Wind Power Plant Part 2/2
    • Patrycja Bałdowska-Witos
    • Krzysztof Doerffer
    • Michał Pysz
    • Piotr Doerffer
    • Andrzej Tomporowski
    • Marek Opielak
    2021 Full text Materials

    The process of conversion of wind kinetic energy into electricity in innovative wind power plant emits practically no harmful substances into the environment. However, the production stage of its components requires a lot of energy and materials. The biggest problem during production plan-ning process of an innovative wind power plant is selection of materials and technologies and, consequently, the waste generated at this stage. Therefore, the aim of this publication was to conduct an environmental analysis of the life cycle of elements of a wind turbine by means of life cycle assessment (LCA) method. The object of the research was a wind power plant divided into five sets of components (tower, turbine structure, rotors, generators, and instrumentation), made mainly of steel and small amounts of polymer materials. Eco-indicator 99 was used as an analytical procedure. The impact of the subjects of analysis on human health, ecosystem quality and re-sources was assessed. Among the analyzed components, the highest level of negative impact on the environment was characterized by the life cycle of the wind turbine tower. The application of recycling processes is reducing the negative impact on the environment in the perspective of the entire life cycle of all studied elements of the wind power plant construction.

  • Mapping negative unintended consequences of disruptive technologies use in smart cities
    • Nina Rizun
    • Magdalena Ciesielska
    • Gabriela Viale Pereira
    • Charalampos Harris Alexopoulos
    2021

    Smart cities governance (SCG) consists of both to foster technology-enabled innovation, and to utilize disruptive technologies (DT) outcomes and impacts to increase public value of urban services. Despite widespread discussion of DT benefits, scientific literature identifies multiple determinants of unintended negative consequences (UC) of DT deployment in smart city initiatives. By considering UC as the negative aspects resulting from underestimating or ignoring the scale of such consequences, this study analyses the objectives of SCG and the negative unintended effects of five selected DT initiatives on these objectives’ implementation. The main contribution of this paper is the identification of determinants of negative UC of Smart City disruptive technologies initiatives and identifying the structure of their impact on the SCG objectives. The results indicate the need to establish a new governance framework of UC in smart cities as a tool to support local governments dealing with the changes caused by DT use in the smart city ecosystem

  • Mapping of the Covid-19 Vaccine Uptake Determinants From Mining Twitter Data
    • Anna Baj-Rogowska
    2021 Full text IEEE Access

    Opinion polls on vaccine uptake clearly show that Covid-19 vaccine hesitancy is increasing worldwide. Thus, reaching herd immunity not only depends on the efficacy of the vaccine itself, but also on overcoming this hesitancy of uptake in the population. In this study, we revealed the determinants regarding vaccination directly from people’s opinions on Twitter, based on the framework of the 6As taxonomy. Covid-19 vaccine acceptance depends mostly on the characteristics of new vaccines (i.e. their safety, side effects, effectiveness, etc.), and the national vaccination strategy (i.e. immunization schedules, quantities of vaccination points and their localization, etc.), which should focus on increasing citizens' awareness, among various other factors. The results of this study point to areas for potentially improving mass campaigns of Covid-19 immunization to increase vaccine uptake and its coverage and also provide insight into possible directions of future research.

  • Marian Żerebecki – saper, inżynier, wykładowca Politechniki Gdańskiej – mało znany, ale czy zapomniany?
    • Witold Parteka
    2021 Pismo PG

    Artykuł przedstawia sylwetkę Mariana Żerebeckiego – sapera, inżyniera, wykładowcy Politechniki Gdańskiej

  • Marine and Cosmic Inspirations for AI Algorithms
    • Marek Galewski
    • Piotr Duba
    2021 Full text Per mare ad astra

    Artificial Intelligence (AI) is a scientific area that currently sees an enormous growth. Various new algorithms and methods are developed and many of them meets practical, successful applications. Authors of new algorithms draw different inspirations. Probably the most common one is the nature. For example, Artificial Neural Networks were inspired by the structure of human brain and nervous system while the classic Genetic Algorithm was inspired by the biological evolution process. One of the important areas of AI algorithms applications are optimization problems which can be encountered in practically all fields of science, technology, and everyday life. Amongst AI algorithms used to solve optimization problems, especially large, and still broadening group are swarm intelligence algorithms. They are nature-inspired, meta-heuristic algorithms which usually solve optimization problems by mimicking biological or physical phenomena. They are based mainly on observations of behaviours of various species of animals for example birds , ants , grasshoppers , bees , bats , wolves , fish , dolphins and many other or implement physics laws or environmental phenomena like laws of gravity , motion of galaxies , lightning formation , hydrologic cycle , water evaporation , etc. The general advantages of swarm optimization are: simplicity, easy implementation and the lack of the objective function gradient information requirement. They are usually fast converging and can bypass local optima. Despite large number of algorithms there is no one, ultimate algorithm that solves all types of problems (single- and multi-objective, uni- and multi-modal, with and without boundaries, etc.). Thus, there is a permanent need for more algorithms with new, original inspirations. The paper presents general advantages of swarm intelligence algorithms and a short review of selected, interesting optimization algorithms that draw inspirations from marine nature and cosmic space. These are Gravitational Search Algorithm, Artificial Fish Swarm Optimization, Krill Herd, Whale Optimization Algorithm and Salp Swarm Algorithm

  • Marine Fuel Sulphur Limit Impact on Air Pollution
    • Dominik Kreft
    2021 International Journal of Ecology and Development

    The article presents calculation of Sulphur oxides percentage drop rate in marine industry recorded after 01.01.2020 when new limits, provided by International Maritime Organizations legislation, became effective. Ships’ SOx global emission was estimated and compared between 4th quarter 2019 and 1st quarter 2020. For more accurate estimation 3 seaside cities with big harbors were selected for statistical analysis. Noticeable SOx decrease was observed. In one case the drop was at similar level to theoretical. There were found significant correlations between heavy fuel oil bunker and SOx level in the air.

  • Massively parallel linear-scaling Hartree–Fock exchange and hybrid exchange–correlation functionals with plane wave basis set accuracy
    • Jacek Dziedzic
    • James C. Womack
    • Rozh Ali
    • Chris-Kriton Skylaris
    2021 Full text JOURNAL OF CHEMICAL PHYSICS

    We extend our linear-scaling approach for the calculation of Hartree–Fock exchange energy using localized in situ optimized orbitals [Dziedzic et al., J. Chem. Phys. 139, 214103 (2013)] to leverage massive parallelism. Our approach has been implemented in the ONETEP (Order-N Electronic Total Energy Package) density functional theory framework, which employs a basis of non-orthogonal generalized Wannier functions (NGWFs) to achieve linear scaling with system size while retaining controllable near-complete-basis-set accuracy. For the calculation of Hartree–Fock exchange, we use a resolution-of-identity approach, where an auxiliary basis set of truncated spherical waves is used to fit products of NGWFs. The fact that the electrostatic potential of spherical waves (SWs) is known analytically, combined with the use of a distance-based cutoff for exchange interactions, leads to a calculation cost that scales linearly with the system size. Our new implementation, which we describe in detail, combines distributed memory parallelism (using the message passing interface) with shared memory parallelism (OpenMP threads) to efficiently utilize numbers of central processing unit cores comparable to, or exceeding, the number of atoms in the system. We show how the use of multiple time-memory trade-offs substantially increases performance, enabling our approach to achieve superlinear strong parallel scaling in many cases and excellent, although sublinear, parallel scaling otherwise. We demonstrate that in scenarios with low available memory, which preclude or limit the use of time-memory trade-offs, the performance degradation of our algorithm is graceful. We show that, crucially, linear scaling with system size is maintained in all cases. We demonstrate the practicability of our approach by performing a set of fully converged production calculations with a hybrid functional on large imogolite nanotubes up to over 1400 atoms. We finish with a brief study of how the employed approximations (exchange cutoff and the quality of the SW basis) affect the calculation walltime and the accuracy of the obtained results.

  • Matematyka na zajęciach z arkuszy kalkulacyjnych
    • Agnieszka Bartłomiejczyk
    • Dawid Ptach
    • Marcin Wata
    2021 Full text Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    Na zajęciach, zarówno w szkole, jak i na uczelni, do pokazania technicznej strony użycia arkusza kalkulacyjnego, tj.dostępnych funkcjonalności oraz organizacji danych, często wykorzystuje się proste zadania matematyczne. W naszym artykule zwracamy uwagę na potrzebę rozumienia przez użytkowników arkuszy kalkulacyjnych pojęć matematycznych, które umożliwiają odpowiednie przygotowanie danych oraz zinterpretowanie uzyskanych za pomocą narzędzi arkusza wyników. Zajęcia z Technologii informacyjnych, Arkuszy kalkulacyjnych czy z Zarządzania projektami są okazją do pokazania wagi interdyscyplinarności w nauce, w tym do motywowania, głębszego poznania i zrozumienia matematyki.

  • Materiały sorpcyjne wykorzystywane w maskach ochronnych
    • Paulina Nowicka
    • Marta Orciuch
    • Sandra Orylska
    • Sandra Rosa
    • Dominika Sołtyszewska
    • Natalia Łukasik
    2021 Full text Analityka: Nauka i Praktyka

    Od zarania dziejów ludzie starają się chronić przed chorobami zakaźnymi, stosując środki ochrony osobistej, do których należą maski ochronne. Z uwagi na obecnie panującą pandemię wirusa SARS-CoV-2, noszenie masek stało się normą w walce z koronawirusem. Jednak zagrożenia dla górnych dróg oddechowych nie stanowią wyłącznie wirusy, lecz również cząstki stałe zawieszone w powietrzu. Szczególnie w krajach wysoko uprzemysłowionych, narażenie na duże stężenie pyłów może przyczynić się nawet do śmierci, gdy dostaną się one do krwioobiegu. Z tego względu, noszenie masek może znacząco poprawić jakość zdrowia i życia. W tym artykule scharakteryzowano dostępne filtry w maskach ochronnych, do których należą membrany z nanowłókien polimerowych, filtry na bazie węgla aktywnego oraz filtry na bazie struktur metaloorganicznych (MOF). Przedstawiono także nowe rozwiązania, takie jak maski na bazie antybakteryjnych materiałów, które mają uskutecznić ochronę przed patogenami.

  • Mathematical approach to design 3D scaffolds for the 3D printable bone implant
    • Wiktoria Wojnicz
    • Marek Augustyniak
    • Piotr Borzyszkowski
    2021 Full text Biocybernetics and Biomedical Engineering

    This work demonstrates that an artificial scaffold structure can be designed to exhibit mechanical properties close to the ones of real bone tissue, thus highly reducing the stress-shielding phenomenon. In this study the scan of lumbar vertebra fragment was reproduced to create a numerical 3D model (this model was called the reference bone sample). New nine 3D scaffold samples were designed and their numerical models were created. Using the finite element analysis, a static compression test was performed to assess the effective Young modulus of each tested sample. Also, two important metrics of each sample were assessed: relative density and surface area. Each new designed 3D scaffold sample was analyzed by considering two types of material properties: metal alloy properties (Ti-6Al-4V) and ABS polymer properties. Numerical analysis results of this study confirm that 3D scaffold used to design a periodic structure, either based on interconnected beams (A, B, C, D, E and F units) or made by removing regular shapes from base solid cubes (G, H, I units), can be refined to obtain mechanical properties similar to the ones of trabecular bone tissue. Experimental validation was performed on seven scaffolds (A, B, C, D, E, F and H units) printed from ABS material without any support materials by using Fused Deposition Modeling (FMD) technology. Results of experimental Young modulus of each printed scaffold are also presented and discussed.

  • Mathematical model of the energy consumption calculation during the pine sawn wood (Pinus sylvestris L.) drying process
    • Aleksandra Konopka
    • Jacek Barański
    • Kazimierz Orłowski
    • Dariusz Mikielewicz
    • Ladislav Dzurenda
    2021 Full text WOOD SCIENCE AND TECHNOLOGY

    The article presents the modification of the existing mathematical model to calculate energy consumption during conventional drying process. Apart from energy consumption the model permits to estimate the time of high-temperature drying process. The drying medium is air and superheated steam mixture. The obtained calculation results were compared with conducted experimental tests of drying square-edged sawn sapwood timber (Pinus sylvestris L.). The pine sawn wood samples were dried according to three different drying modes, namely mild, normal and intense. The experiments were performed in a semi-industrial scale drying chamber. On the basis of the experimental research available, existing mathematical models of drying wood have been improved. The developed model included the following changes: a different drying time for each mode and type of drying medium (moisturized air or air and superheated steam mixture). The use of an intensive drying mode significantly reduced the drying process time. The developed mathematical model revealed that the energy consumption of the drying process increases with the intensity of the mode used.

  • Measured and predicted freeze-thaw days frequencies in climate change conditions in central Poland
    • Arkadiusz Bartczak
    • Halina Kaczmarek
    • Michał Badocha
    • Michał Krzemiński
    • Sebastian Tyszkowski
    2021 Full text PeerJ

    The rate of progression of geomorphological phenomena is greatly influenced by freeze-thaw processes. In the face of air temperature increasing over the past few decades, a question of the future impact of these processes arises, notably in the temperate and cold climate zones. Using the mean, maximum and minimum daily air temperature data in the period 1951–2018 obtained from three weather stations located in the vicinity of Jeziorsko reservoir (central Poland), we have determined the mathematical correlation, described with a polynomial function, between the mean monthly air temperature and the monthly number of freeze-thaw days (FTD). A freeze-thaw day is a day when the maximum air temperature is above 0 C while the minimum air temperature equals or is below this threshold. The number of FTDs within the study area averaged 64–71 and demonstrated a downward trend of 2–4 FTDs/10 years. The study period (1951–2018), includes a clearly marked distinct sub-period (1991–2018), when the reservoir was in operation, which experienced 58–68 FTDs. Considering the assumed rise in temperature, one should expect a further, though slightly slower, decline in the future number of FTDs. Depending on the accepted model of the temperature increase, which for the area of Poland (Central Europe) in the perspective of 30 years oscillates between +1.1 to +1.3 C, the number of FTDs within the study area is expected to decline by −4.5 to −5.3 FTD, i.e. 6–7% and 5.4–5.5 FTD i.e. 8–9% respectively.

  • Measurement Campaign and Mathematical Model Construction for the Ship Zodiak Magnetic Signature Reproduction
    • Jarosław Tarnawski
    • Krystian Buszman
    • Mirosław Wołoszyn
    • Tomasz Rutkowski
    • Adam Cichocki
    • R. Józwiak
    2021 Full text MEASUREMENT

    The paper presents the partial work done within the framework of the EDA Siramis II project focused on magnetic signature reproduction of ships. Reproduction is understood here as the ability to determine the magnetic anomaly of the local Earth magnetic field in any direction and at any measurement depth due to the presence of the analysed object. The B-91 type hydrographic ship Zodiak was selected as the real case study. The work was divided into two main stages: the development of a measurement campaign taking into account physical measurements, and the development of a mathematical model on the basis of the measured values. The measurement campaign included: preparation of the measuring range, selection of equipment for the measurement of magnetic quantities and geographical location, and data recording while the ship passes the measuring point according to the designated course. As a result of the measurement campaign, magnetic flux density components were collected in different positions in relation to the measuring instruments and the ship's heading. A multi-dipole model was used to build the mathematical model in accordance with the idea of inverse modelling. The effectiveness of this model was previously checked on synthetic data of virtual ships generated using the finite element method. Experiments performed with simulation models were helpful in determining the structure of the model, the nature of the data, and the number of samples needed to properly determine the multi-dipole model parameters. The parameters were determined using the nonlinear least squares method according to the idea of data fitting. The classical Ridge and Lasso regularization methods were applied to prevent the developed multi-dipole model from overfitting. Other regularization methods based on GPS accuracy marks and modification of fitness functions were also considered. The verification was done using real data: the data generated by the model was compared with patterns recorded during the Zodiak measurement campaign. High degree of conformity of the shape of characteristics was obtained. Moreover, the correctness of model execution was confirmed by low values of quantitative indices such as RMSE and MAE representing modelling errors. The methodology presented in the paper is quite universal and can be used to determine the signatures of other ferromagnetic objects.

  • Measurement of Seafloor Acoustic Backscatter Angular Dependence at 150 kHz Using a Multibeam Echosounder
    • Karolina Trzcińska
    • Jarosław Tęgowski
    • Paweł Poćwiardowski
    • Łukasz Janowski
    • Jakub Zdroik
    • Aleksandra Kruss
    • Maria Rucińska
    • Zbigniew Łubniewski
    • Jens Schneider von Deimling
    2021 Full text Remote Sensing

    Acoustic seafloor measurements with multibeam echosounders (MBESs) are currently often used for submarine habitat mapping, but the MBESs are usually not acoustically calibrated for backscattering strength (BBS) and cannot be used to infer absolute seafloor angular dependence. We present a study outlining the calibration and showing absolute backscattering strength values measured at a frequency of 150 kHz at around 10–20 m water depth. After recording bathymetry, the co-registered backscattering strength was corrected for true incidence and footprint reverberation area on a rough and tilted seafloor. Finally, absolute backscattering strength angular response curves (ARCs) for several seafloor types were constructed after applying sonar backscattering strength calibration and specific water column absorption for 150 kHz correction. Thus, we inferred specific 150 kHz angular backscattering responses that can discriminate among very fine sand, sandy gravel, and gravelly sand, as well as between bare boulders and boulders partially overgrown by red algae, which was validated by video ground-truthing. In addition, we provide backscatter mosaics using our algorithm (BBS-Coder) to correct the angle varying gain (AVG). The results of the work are compared and discussed with the published results of BBS measurements in the 100–400 kHz frequency range. The presented results are valuable in extending the very sparse angular response curves gathered so far and could contribute to a better understanding of the dependence of backscattering on the type of bottom habitat and improve their acoustic classification.

  • Measurement report: Spatial variations in ionic chemistry and water-stable isotopes in the snowpack on glaciers across Svalbard during the 2015–2016 snow accumulation season
    • Elena Barbaro
    • Krystyna Koziol
    • Mats P. Björkman
    • Carmen P. Vega
    • Christian Zdanowicz
    • Tonu Martma
    • Jean-Charles Gallet
    • Daniel Kępski
    • Catherine Larose
    • Bartłomiej Luks
    • Florian Tolle
    • Thomas Schuler
    • Aleksander Uszczyk
    • Andrea Spolaor
    2021 Full text ATMOSPHERIC CHEMISTRY AND PHYSICS

    The Svalbard archipelago, located at the Arctic sea-ice edge between 74 and 81∘ N, is ∼60 % covered by glaciers. The region experiences rapid variations in atmospheric flow during the snow season (from late September to May) and can be affected by air advected from both lower and higher latitudes, which likely impact the chemical composition of snowfall. While long-term changes in Svalbard snow chemistry have been documented in ice cores drilled from two high-elevation glaciers, the spatial variability of the snowpack composition across Svalbard is comparatively poorly understood. Here, we report the results of the most comprehensive seasonal snow chemistry survey to date, carried out in April 2016 across 22 sites on seven glaciers across the archipelago. At each glacier, three snowpits were sampled along the altitudinal profiles and the collected samples were analysed for major ions (Ca2+, K+, Na+, Mg2+, NH+4, SO2−4, Br−, Cl−, and NO−3) and stable water isotopes (δ18O, δ2H). The main aims were to investigate the natural and anthropogenic processes influencing the snowpack and to better understand the influence of atmospheric aerosol transport and deposition patterns on the snow chemical composition. The snow deposited in the southern region of Svalbard is characterized by the highest total ionic loads, mainly attributed to sea-salt particles. Both NO−3 and NH+4 in the seasonal snowpack reflect secondary aerosol formation and post-depositional changes, resulting in very different spatial deposition patterns: NO−3 has its highest loading in north-western Spitsbergen and NH+4 in the south-west. The Br− enrichment in snow is highest in north-eastern glacier sites closest to areas of extensive sea-ice coverage. Spatial correlation patterns between Na+ and δ18O suggest that the influence of long-range transport of aerosols on snow chemistry is proportionally greater above 600–700 m a.s.l.

  • Measurements of the Hydraulic Fluids Compressibility
    • Leszek Osiecki
    2021

    Performance of the hydrostatic high-pressure drive systems is affected by the changes of working fluid’s volume. Presence of air bubbles in the fluid cause this problem to be even more serious. To study this phenomenon precise measurements of fluid’s bulk modulus are necessary. Differ-ent measurement methods are applied, but they are either limited to low pressure range or give inaccurate results. To solve the problem the new measurement device was built. It allows to directly measure volume changes of both pure fluid or fluid-air mixture within the wide pressure and temperature range. Both adiabatic and isothermal module may be determined, the tested fluid may be pure or aerated.. Measurements of different fluids were made including vegetable oils (rapeseed, sunflower and linseed), mineral oil and synthetic oil.

  • Measurements of the optical and thermal properties of the 2D black phosphorus coating
    • Paulina Listewnik
    • Małgorzata Szczerska
    • Paweł Jakóbczyk
    2021 Full text Materials Research Express

    Black phosphorus is a 2D material, which properties are still being discovered. In this paper, the sensitivity to the temperature of a few-layer black phosphorus coating deposited, on the surface of a microsphere-based fiber-optic sensor, by a dip-coating method is presented. The coating was investigated after 2, 3, and 5 deposition cycles and during temperature growth from 50 °C to 300 °C in an interferometric setup. The intensity of the reflected signal increases with each applied layer. During the investigation of the thermal properties, in the range of 50 °C–200 °C, the polynomial growth rate of the reflected signal can be observed, whereas, for the temperatures over 200 °C, the measured peak intensity of the reflected signal stabilizes at a nearly constant level.

  • Measurements of Thermal Conductivity of LWC Cement Composites Using Simplified Laboratory Scale Method
    • Marzena Kurpińska
    • Jarosław Karwacki
    • Artur Maurin
    • Marek Kin
    2021 Full text Materials

    The implementation of low-energy construction includes aspects related to technological and material research regarding thermal insulation. New solutions are sought, firstly, to reduce heat losses and, secondly, to improve the environment conditions in isolated rooms. The effective heat resistance of insulating materials is inversely proportional to temperature and humidity. Cement composites filled with lightweight artificial aggregates may be a suitable material. Selecting a proper method for measuring the thermal conductivity of concrete is important to achieve accurate values for calculating the energy consumption of buildings. The steady state and transient methods are considered the two main thermal conductivity measurement approaches. Steady state is a constant heat transfer, whereby the temperature or heat flow is time independent. In the transient method, temperature changes over time. Most researchers have measured the conductivity of cement-based materials based on transient methods. The availability and cost of equipment, time for experimental measurements and measurement ability for moist specimens may be some of the reasons for using this method. However, considering the accuracy of the measurements, the steady state methods are more reliable, especially for testing dry materials. Four types of composites were investigated that differed in filler: natural aggregate, sintered fly ash filler, sintered clay and granular foam glass aggregate. The method of preparing the samples for testing is especially important for the obtained results. The samples, with a specific surface roughness, will show a lower coefficient of thermal conductivity by 20–30%; therefore, the selection of the type of contact layer between the plate of the measuring device and the sample is of particular importance.

  • Measures of Functional Reliability of Two-Lane Highways
    • Krzysztof Ostrowski
    • Marcin Budzyński
    2021 Full text ENERGIES

    Rural two-lane highways are the most common road type both in Poland and globally. In terms of kilometres, their length is by far greater than that of motorways and expressways. They are roads of one carriageway for each direction, which makes the overtaking of slower vehicles possible only when there is a gap in the stream of traffic moving from the opposite direction. Motorways and express roads are dual carriageways that are expected to support high speed travel mainly over long distances. Express roads have somewhat lower technical parameters and a lower speed limit than motorways. Two-lane highways are used for both short- and long-distance travel. The paper presents selected studies conducted in Poland in 2016–2018 on rural two-lane highways and focuses on the context of the need for their reliability. The research was carried out on selected short and [longer road sections located in various surroundings, grouped in terms of curvature change rate CCR, longitudinal slopes and cross-sections (width of lanes and shoulders). The studies of traffic volumes, travel time and travel speed, as well as traffic density, will be used to analyze traffic performance and identify measures of travel time reliability. The analyzed roads were characterized by good technical parameters and significant variability of traffic volume throughout the day, week and year. Some roads experience congestion, i.e., situations in which traffic volume Q is close to or above respective road capacity C. In order to determine the form of the suitable reliability measures, it will be important to determine the extent to which a road’s geometric and traffic characteristics impact travel speed and time. The paper presents well-known reliability measures for dual carriageways and proposes new measures, along with an evaluation of their usefulness in the assessment of the functioning of two-lane highways.

  • Mechanical analysis of eccentric defected bilayer graphene sheets considering the van der Waals force
    • Shahriar Dastjerdi
    • Mohammad Malikan
    2021 Full text Proceedings of the Institution of Mechanical Engineers Part N-Journal of Nanomaterials Nanoengineering and Nanosystems

    In this article, we have tried to simulate nonlinear bending analysis of a double-layered graphene sheet which contains a geometrical imperfection based on an eccentric hole. The first-order shear deformation theory is considered to obtain the governing equations. Also, the nonlinear von Kármán strain field has been assumed in order to obtain large deformations. Whereas the double-layered graphene sheet has been considered, the effect of van der Waals forces has been taken into account in the analysis. In order to implement the nanoscale impact, the nonlocal elasticity theory has been employed. The solution methodology, which is here based on the semi-analytical polynomial method solving technique presented previously by the authors, has been applied and again its efficiency has been demonstrated due to its highly accurate results. Due to the fact that this research has been done for the first time and there is no validation available, the results of the local single layer sheet are compared with ABAQUS software. The effects of some other parameters on the results have been studied such as the value of eccentricity, van der Waals interaction, and nonlocal parameter.

  • Mechanical Behavior of Bi-Layer and Dispersion Coatings Composed of Several Nanostructures on Ti Substrate
    • Dorota Rogala-Wielgus
    • Beata Majkowska-Marzec
    • Andrzej Zieliński
    • Bartłomiej J. Jankiewicz
    2021 Full text Applied Sciences-Basel

    Three coatings suitable for biomedical applications, including the dispersion coating composed of multi-wall carbon nanotubes (MWCNTs), MWCNTs/TiO2 bi-layer coating, and MWCNTs-Cu dispersion coating, were fabricated by electrophoretic deposition (EPD) on Ti Grade II substrate. Optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and nanoindentation were applied to study topography, chemical, and phase composition, roughness, hardness, Young’s modulus, plastic, and elastic behavior. The results showed that the best mechanical properties in terms of biomedical application were achieved for the MWCNTs coating with titania outer layer. Nevertheless, both the addition of nanocopper and titania improved the mechanical resistance of the base MWCNTs coating. Compared to our previous experiments on Ti13Nb13Zr alloy, a general tendency is observed to form more homogenous coatings on pure metal than on the alloy, in which chemical and phase compositions are more complex.

  • Mechanical Behavior of Bi-Layer and Dispersion Coatings Composed of Several Nanostructures on Ti13Nb13Zr Alloy
    • Dorota Rogala-Wielgus
    • Beata Majkowska-Marzec
    • Andrzej Zieliński
    • Michał Bartmański
    • Bartosz Bartosewicz
    2021 Full text Materials

    Titanium implants are commonly used because of several advantages, but their surface modification is necessary to enhance bioactivity. Recently, their surface coatings were developed to induce local antibacterial properties. The aim of this research was to investigate and compare me-chanical properties of three coatings: multi-wall carbon nanotubes (MWCNTs), bi-layer composed of an inner MWCNTs layer and an outer TiO2 layer, and dispersion coatings comprised of simulta-neously deposited MWCNTs and nanoCu, each electrophoretically deposited on the Ti13Nb13Zr alloy. Optical microscopy, scanning electron microscopy, X-ray electron diffraction spectroscopy, and nanoindentation technique were applied to study topography, chemical composition, hardness, plastic and elastic properties. The results demonstrate that the addition of nanocopper or titanium dioxide to MWCNTs coating increases hardness, lowers Young’s modulus, improves plastic and elastic properties, wear resistance under deflection, and plastic deformation resistance. The results can be attributed to different properties, structure and geometry of applied particles, various dep-osition techniques, and the possible appearance of porous structures. These innovative coatings of simultaneously high strength and elasticity are promising to apply for deposition on long-term ti-tanium implants.

  • Mechanical, durability, depolluting and electrical properties of multifunctional mortars prepared with commercial or waste carbon-based fillers
    • Alessandra Mobili
    • Alberto Belli
    • Chiara Giosuè
    • Mattia Pierpaoli
    • Luca Bastianelli
    • Alida Mazzoli
    • Maria Letizia Ruello
    • Tiziano Bellezze
    • Francesca Tittarelli
    2021 Full text CONSTRUCTION AND BUILDING MATERIALS

    Carbon-based fillers from industrial wastes and commercial ones were compared to improve the properties of lime-based mixes. As commercial fillers, graphene nanoplatelets and activated carbon were used, whereas as industrial wastes a char obtained by the gasification of biomasses and a used foundry sand were chosen. Carbon-based wastes were found to be a good cost-effective alternative to commercial carbon based fillers to increase the compressive strength (of about 25%) and to reduce water capillary absorption (of about 50%) thanks to the paste refinement; to enhance depollution capacity (of about 25%) and increase both electrical conductivity (up to 65%) and electromagnetic shielding effectiveness (of about 6%) of the hardened compounds thanks to the carbon content.

  • Mechanical Performance and Environmental Assessment of Sustainable Concrete Reinforced with Recycled End-of-Life Tyre Fibres
    • Magdalena Pawelska-Mazur
    • Maria Kaszynska
    2021 Full text Materials

    The presented research’s main objective was to develop the solution to the global problem of using steel waste obtained during rubber recovery during the tire recycling. A detailed comparative analysis of mechanical and physical features of the concrete composite with the addition of recycled steel fibres (RSF) in relation to the steel fibre concrete commonly used for industrial floors was conducted. A study was carried out using micro-computed tomography and the scanning electron microscope to determine the fibres’ characteristics, incl. the EDS spectrum. In order to designate the full performance of the physical and mechanical features of the novel composite, a wide range of tests was performed with particular emphasis on the determination of the tensile strength of the composite. This parameter appointed by tensile strength testing for splitting, residual tensile strength test (3-point test), and a wedge splitting test (WST), demonstrated the increase of tensile strength (vs unmodified concrete) by 43%, 30%, and 70% relevantly to the method. The indication of the reinforced composite’s fracture characteristics using the digital image correlation (DIC) method allowed to illustrate the map of deformation of the samples during WST. The novel composite was tested in reference to the circular economy concept and showed 31.3% lower energy consumption and 30.8% lower CO2 emissions than a commonly used fibre concrete.

  • Mechanical Properties and Residual Stress Measurements of Grade IV Titanium and Ti-6Al-4V and Ti-13Nb-13Zr Titanium Alloys after Laser Treatment
    • Magdalena Jażdżewska
    • Dominika Kwidzińska
    • Wiktor Seyda
    • Dariusz Fydrych
    • Andrzej Zieliński
    2021 Full text Materials

    Nowadays, surface engineering focuses on research into materials for medical applications. Titanium and its alloys are prominent, especially Ti-6Al-4V and Ti-13Nb-13Zr. Samples made of pure grade IV titanium and the titanium alloys Ti-6Al-4V and Ti-13Nb-13Zr were modified via laser treatment with laser beam frequency f = 25 Hz and laser beam power P = 1000 W during a laser pulse with duration t = 1 ms. Subsequently, to analyze the properties of the obtained surface layers, the following tests were performed: scanning electron microscopy, chemical and phase composition analysis, wetting angle tests and roughness tests. The assessment of the impact of the laser modification on the internal stresses of the investigated materials was carried out by comparing the values of the stresses of the laser-modified samples to those of the reference samples. The obtained results showed increased values of tensile stresses after laser modification: the highest value was found for the Ti-6Al-4V alloy at 6.7434 GPa and the lowest for pure grade IV titanium at 3.742 GPa. After laser and heat treatment, a reduction in the stress was observed, together with a significant increase in the hardness of the tested materials, with the highest value for Ti-6Al-4V alloy at 27.723 GPa. This can provide better abrasion resistance and lower long-term toxicity, both of which are desirable when using Ti-6Al-4V and Ti-13Nb-13Zr alloys for implant materials.

  • Mechanical Properties, Microstructure and Surface Quality of Polypropylene Green Composites as a Function of Sunflower Husk Waste Filler Particle Size and Content
    • Mateusz Barczewski
    • Jacek Andrzejewski
    • Radomir Majchrowski
    • Kamil Dobrzycki
    • Krzysztof Formela
    2021 Full text Journal of Renewable Materials

    Agricultural waste is a still untapped source of materials that can, in case of proper utilization, significantly improve the sustainability of polymers and their composites. In this work, polymer composites based on isotactic polypropylene were produced incorporating ground sunflower husk in the amount of 10 wt% and 20 wt%. The work’s main objective is to evaluate how preliminary fractioning of this agricultural waste filler affects the thermomechanical properties, microstructure and surface topology of polypropylene-based injection molded composites. The composites were analyzed for mechanical properties (tensile, impact strength and hardness), thermomechanical properties (Vicat softening point VST, heat deflection temperature HDT, and dynamic thermomechanical analysis DMTA) with reference to morphological changes evaluated using scanning electron microscopy (SEM). The quality of the produced composites was assessed on the basis of the analysis of the surface topology of the injected composites. It has been shown that the larger particle size of used filler has a direct impact on increasing composite stiffness in the room and elevated temperature. Moreover, a relationship was demonstrated between the size of the filler and the deterioration of the tensile strength in the case of composites with a higher content of filler. The results show that the addition of sunflower husk as a particle-shaped waste filler is an effective method to increase sustainability of polypropylene-based green composites with beneficial thermomechanical properties and to reduce the residue of sunflower husk from industrial oil production.

  • Mechanical Properties of Bio-Composites Based on Epoxy Resin and Nanocellulose Fibres
    • Martyna Roszowska-Jarosz
    • Joanna Masiewicz
    • Marcin Kostrzewa
    • Wojciech Kucharczyk
    • Wojciech Żurowski
    • Justyna Kucińska-Lipka
    • Paweł Przybyłek
    2021 Full text Materials

    The aim of our research was to investigate the effect of a small nanocellulose (NC) addition on an improvement of the mechanical properties of epoxy composites. A procedure of chemical extraction from pressed lignin was used to obtain nanocellulose fibers. The presence of nanoparticles in the cellulose pulp was confirmed by FTIR/ATR spectra as well as measurement of nanocellulose particle size using a Zetasizer analyzer. Epoxy composites with NC contents from 0.5% to 1.5% w/w were prepared. The obtained composites were subjected to strength tests, such as impact strength (IS) and resistance to three-point bending with a determination of critical stress intensity factor (Kc). The impact strength of nanocellulose composites doubled in comparison to the unmodified epoxy resin (EP 0). Moreover, Kc was increased by approximately 50% and 70% for the 1.5 and 0.5% w/w NC, respectively. The maximum value of stress at break was achieved at 1% NC concentration in EP and it was 15% higher than that for unmodified epoxy resin. The highest value of destruction energy was characterized by the composition with 0.5% NC and corresponds to the increase of 102% in comparison with EP 0. Based on the analysis of the results it was noted that satisfactory improvement of the mechanical properties of the composite was achieved with a very small addition of nanofiller while other research indicates the need to add much more nanocellulose. It is also expected that this kind of use of raw materials will allow increasing the economic efficiency of the nanocomposite preparation process. Moreover, nanocomposites obtained in this way can be applied as elements of machines or as a modified epoxy matrix for sandwich composites, enabling production of the structure material with reduced weight but improved mechanical properties.

  • Mechanical simulation of artificial gravity in torus-shaped and cylindrical spacecraft
    • Shahriar Dastjerdi
    • Mohammad Malikan
    • Victor Eremeev
    • Bekir Akgöz
    • Ömer Civalek
    2021 Full text ACTA ASTRONAUTICA

    Large deformations and stress analyses in two types of space structures that are intended for people to live in space have been studied in this research. The structure under analysis is assumed to rotate around the central axis to create artificial gravitational acceleration equal to the gravity on the Earth's surface. The analysis is fully dynamic, which is formulated based on the energy method by using the first-order shear deformation shell theory in two systems, cylindrical and torus. Also, the nonlinear von Kármán strain field has been assumed. The obtained set of partial differential equations has been solved using the semi-analytical polynomial solution method (SAPM). The main purpose of this paper is to study the effects of unusual conditions in the space outside the Earth's atmosphere (which is a complete vacuum environment without pressure) on the strength of the analyzed structure. The numerical results of the governing equations have been evaluated using those of other studies and the simulation efficiency performed in this research has been proven. Finally, the effect of important parameters on the numerical results, including the angular velocity of the structure (which causes artificial gravity), the amount of imposed mechanical and hygro-thermal loads, the structure size and material specifications have been investigated in more detail.

  • Mechanism of Li nucleation at graphite anodes and mitigation strategies
    • Chao Peng
    • Arihant Bhandari
    • Jacek Dziedzic
    • John R. Owen
    • Chris-Kriton Skylaris
    • Denis Kramer
    2021 Full text Journal of Materials Chemistry A

    Lithium metal plating is a critical safety issue in Li-ion cells with graphite anodes, and contributes significantly to ageing, drastically limiting the lifetime and inducing capacity loss. Nonetheless, the nucleation mechanism of metallic Li on graphite anodes is still poorly understood. But in-depth understanding is needed to rationally design mitigation measures. In this work, we conducted FirstPrinciples studies to elucidate the Li nucleation mechanism on graphite surfaces. These large-scale density-functional-theory (DFT) calculations indicate that nano-particulate Li forms much more readily than classical nucleation theory predicts. Further, our calculations indicate a crucial role of topological surface states near the zigzag edge, lowering the nucleation barrier by a further 1.32 eV relative to nucleation on the basal plane. Li nucleation, therefore, is likely to initiate at or near the zigzag edges of graphitic particles. Finally, we suggest that chemical doping with a view to reducing the effect of the topological surface states might be a potential mitigation strategy to increase nucleation barriers and reduce the propensity to plate Li near the zigzag edge.

  • Mechanism of recognition of parallel G-quadruplexes by DEAH/RHAU helicase DHX36 explored by molecular dynamics simulations
    • Kazi Hossain
    • Michal Jurkowski
    • Jacek Czub
    • Mateusz Kogut
    2021 Full text Computational and Structural Biotechnology Journal

    Because of high stability and slow unfolding rates of G-quadruplexes (G4), cells have evolved specialized helicases that disrupt these non-canonical DNA and RNA structures in an ATP-dependent manner. One example is DHX36, a DEAH-box helicase, which participates in gene expression and replication by recognizing and unwinding parallel G4s. Here, we studied the molecular basis for the high affinity and specificity of DHX36 for parallel-type G4s using all-atom molecular dynamics simulations. By computing binding free energies, we found that the two main G4-interacting subdomains of DHX36, DSM and OB, separately exhibit high G4 affinity but they act cooperatively to recognize two distinctive features of parallel G4s: the exposed planar face of a guanine tetrad and the unique backbone conformation of a continuous guanine tract, respectively. Our results also show that DSM-mediated interactions are the main contributor to the binding free energy and rely on making extensive van der Waals contacts between the GXXXG motifs and hydrophobic residues of DSM and a flat guanine plane. Accordingly, the sterically more accessible 5′-G-tetrad allows for more favorable van der Waals and hydrophobic interactions which leads to the preferential binding of DSM to the 5′-side. In contrast to DSM, OB binds to G4 mostly through polar interactions by flexibly adapting to the 5′-terminal guanine tract to form a number of strong hydrogen bonds with the backbone phosphate groups. We also identified a third DHX36/G4 interaction site formed by the flexible loop missing in the crystal structure.

  • Mechanism of Solute and Thermal Characteristics in a Casson Hybrid Nanofluid Based with Ethylene Glycol Influenced by Soret and Dufour Effects
    • Muhammad Bilal Hafeez
    • Wojciech Sumelka
    • Umar Nazir
    • Ahmad Hijaz
    • Sameh Askar
    2021 Full text ENERGIES

    This article models a system of partial differential equations (PDEs) for the thermal and solute characteristics under gradients (concentration and temperature) in the magnetohydrodynamic flow of Casson liquid in a Darcy porous medium. The modelled problems are highly non-linear with convective boundary conditions. These problems are solved numerically with a finite element approach under a tolerance of 10−8. A numerical algorithm (finite element approach) is provided and a numerical procedure is discussed. Convergence is also observed via 300 elements. Simulations are run to explore the dynamics of flow and the transport of heat and mass under parametric variation. To examine the impact of a temperature gradient on the transport of mass and the role of a concentration gradient on the transport of heat energy, simulations are recorded. Remarkable changes in temperature and concentration are noted when Dufour and Soret numbers are varied

  • Medially positioned plate in first metatarsophalangeal joint arthrodesis
    • Wojciech Witkowski
    • Leszek Kuik
    • Magdalena Rucka
    • Karol Daszkiewicz
    • Angela Andrzejewska
    • Piotr Łuczkiewicz
    2021 Full text PLOS ONE

    Objective The purpose of this study was to biomechanically compare the stability of first metatarsophalangeal (MTP1) joint arthrodesis with dorsally and medially positioned plates. Methods A physical model of the MTP1 joint consists of printed synthetic bones, a titanium locking plate and screws. In the experiments, samples with dorsally and medially positioned plates were subjected to loading of ground load character in a universal testing machine. Force-displacement relations and relative displacements of bones were recorded. The obtained results were used to validate the corresponding finite element models of the MTP1 joint. Nonlinear finite element simulations of the toe-off phase of gait were performed to determine the deformation and stress state in the MTP1 joint for two positions of the plate. Results In numerical simulations, the maximum displacement in the dorsal direction was noticed at the tip of the distal phalanx and was equal to 19.6 mm for the dorsal plate and 9.63 mm for the medial plate for a resultant force of 150 N. Lower relative bone displacements and smaller plastic deformation in the plate were observed in the model with the medial plate. Stress values were also smaller in the medially positioned plate and locking screws compared to fixation with the dorsal plate. Conclusions A medially positioned locking plate provides better stability of the MTP1 joint than a dorsally positioned plate due to greater vertical bending stiffness of the medial plate. Smaller relative bone displacements observed in fixation with the medial plate may be beneficial for the bone healing process. Moreover, lower stress values may decrease the risk of complications associated with hardware failure.

  • Medieval Bourgeois Tenement Houses as an Archetype for Contemporary Architectural and Construction Solutions: The Example of Historic Downtown Gdańsk
    • Antoni Taraszkiewicz
    • Karol Grębowski
    • Karolina Taraszkiewicz
    • Jarosław Przewłócki
    2021 Full text Buildings

    The basic urban tissue of medieval European cities consisted of brick townhouses. In the cities of northern Europe, these tenements were characterised by a block based on an elongated rectangular plan, covered with a gable roof with a ridge oriented perpendicularly to the street. The side walls of the tenement house were common for both neighbours and constituted a basic structural element. The gable façades were not loaded with ceilings, providing freedom in shaping them. The aim of this work is to determine the reasons why this method of shaping tenement houses in historical city centres has survived to the present day, becoming an archetype for contemporary architectural and construction solutions, despite the passage of time, numerous historical events, war damage, changing architectural styles, fashions and building techniques and technologies. The historical centre of Gdańsk has become the research material in this paper, where by means of such methods as historical source material analysis (iconographic), observation (operationalisation of preserved historical objects), comparative analysis of completed contemporary investments, and 3D modelling of structural systems, an attempt has been made to determine the main factors determining contemporary architectural and structural solutions. The reason for the extraordinary durability of this type of construction model can be found in the enormous rationality and efficiency of this solution. It allows for very intensive use of land, easy access of all front elevations to the main communication routes, cheapness of construction resulting from small spans and use of common structural walls for the neighbouring buildings, ease of shaping gable elevations, and fire safety. Aesthetic considerations are probably also important here, although it should be assumed that their significance began to grow only in the second half of the 19th century. However, it seems that the most important factor which made the model of the mediaeval bourgeois tenement house become an archetype for contemporary architectural and construction solutions is the timeless message contained in this model, a specific code allowing it to be unambiguously identified as a form of urban house – a place of safe living and at the same time a visible sign of the rich history of European cities, an element creating their cultural and spatial identity, a component of the living, constantly transforming urban fabric.

  • Membrane separation processes for the extraction and purification of steviol glycosides: an overview
    • Roberto Castro-Muñoz
    • Elsa Díaz-Montes
    • Alfredo Cassano
    • Emilia Gontarek
    2021 CRITICAL REVIEWS IN FOOD SCIENCE AND NUTRITION

    Steviol glycosides (SGs), as natural sweeteners from Stevia rebaudiana, are currently employed for replacing sugar and its derivatives in several food products and formulations. Such compounds play an essential role in human health. Their usage provides a positive effect on preventing diseases related to sugar consumption, including diabetes mellitus, cancer, and lipid metabolism disorders. The traditional extraction of SGs is performed by means of solvent extraction, which limits their application since the removal of residual solvents is a challenging task requiring further downstream purification steps. In addition, the presence of residual solvents negatively affects the quality of such compounds. Today, food technicians are looking for innovative and improved techniques for the extraction, recovery and purification of SGs. Membrane-based technologies, including microfiltration, ultrafiltration, and nanofiltration, have long been proven to be a valid alternative for efficient extraction and purification of several high added-value molecules from natural sources. Such processes and their possible coupling in integrated membrane systems have been successfully involved in recovery protocols of several compounds, such as metabolites, polyphenols, anthocyanins, natural pigments, proteins, from different sources (e.g., agro-food wastes, plant extracts, fruits, fermentation broths, among others). Herein, we aim to review the current progresses and developments about the extraction of SGs with membrane operations. Our attention has been paid to the latest insights in the field. Furthermore, key process parameters influencing the extraction and purification of SGs are also discussed in detail.

  • Mercury in Living Organisms: Sources and Forms of Occurrence, Bioaccumulation, and Determination Methods
    • Piotr Konieczka
    • Małgorzata Rutkowska
    • Małgorzata Misztal-Szkudlińska
    • Piotr Szefer
    2021 Full text

    Mercury (Hg) is a heavy metal with well-known and broadly tested toxicity. Since Hg pollution and its impacts on human health are of global concern, it has become necessary to develop analytical methodologies that will provide tools to obtain reliable analytical information about the levels of Hg in samples, which very often have a complex matrix composition. This chapter summarizes key information on Hg and its chemical forms, sources of its emission to the environment, and the global Hg cycle. In addition, the concepts of bioaccumulation and biomagnification of Hg along the food chain are characterized. This chapter also describes the analytical methods used in the determination of Hg and its compounds.

  • Mesh dependence study for numerical assessment of hydrodynamic characteristics of windsurfing fin
    • Hanna Pruszko
    2021

    The presented research aims to assess the drag coefficient and lift coefficient versus angle of attack curves for windsurfing fin. Special attention in the research was being paid to the evaluation of the stall angle value. The angle of incidence for which the stall occurs was searched, and the sensitivity of the solution for the mesh resolution was studied. The mesh resolution sensitivity analysis was done by systematically decreasing the value of y+, and the influence on the value of stall angle and slopes of the drag and lift curves were checked. The last part of the research compared the experimental results that are part of the current state of the art.

  • Metabolic Profiles of New Unsymmetrical Bisacridine Antitumor Agents in Electrochemical and Enzymatic Noncellular Systems and in Tumor Cells
    • Anna Mieszkowska
    • Anna M. Nowicka
    • Agata Kowalczyk
    • Agnieszka Potęga
    • Monika Pawłowska
    • Michał Kosno
    • Ewa Augustin
    • Zofia Mazerska
    2021 Full text Pharmaceuticals

    New unsymmetrical bisacridines (UAs) demonstrated high activity not only against a set of tumor cell lines but also against human tumor xenografts in nude mice. Representative UA compounds, named C-2028, C-2045 and C-2053, were characterized in respect to their physicochemical properties and the following studies aimed to elucidate the role of metabolic transformations in UAs action. We demonstrated with phase I and phase II enzymes in vitro and in tumors cells that: (i) metabolic products generated by cytochrome P450 (P450), flavin monooxygenase (FMO) and UDP-glucuronosyltransferase (UGT) isoenzymes in noncellular systems retained the compound’s dimeric structures, (ii) the main transformation pathway is the nitro group reduction with P450 isoenzymes and the metabolism to N-oxide derivative with FMO1, (iii), the selected UGT1 isoenzymes participated in the glucuronidation of one compound, C-2045, the hydroxy derivative. Metabolism in tumor cells, HCT-116 and HT-29, of normal and higher UGT1A10 expression, respectively, also resulted in the glucuronidation of only C-2045 and the specific distribution of all compounds between the cell medium and cell extract was demonstrated. Moreover, P4503A4 activity was inhibited by C-2045 and C-2053, whereas C-2028 affected UGT1A and UGT2B action. The above conclusions indicate the optimal strategy for the balance among antitumor therapeutic efficacy and drug resistance in the future antitumor therapy.

  • Metabolomic and antioxidant properties of different varieties and origins of Dragon fruit
    • Nabil Ali Al-Mekhlafi
    • Ahmed Mediani
    • Nor Hadiani Ismail
    • Faridah Abas
    • Tomasz Dymerski
    • Martyna Lubinska-Szczygeł
    • Suchada Vearasilp
    • Shela Gorinstein
    2021 MICROCHEMICAL JOURNAL

    Dragon fruit has appealed much concern from consumers as a novelty fruit with potent nutritional and medicinal benefits. Dragon fruit quality warrants comprehensive evaluation, based on the contents of pigments and health- promoting natural compounds in different varieties. This study was aimed to evaluate the differences among dragon fruit varieties extracted with methanol–water (CD3OD-D2O) and methanol (CD3OD) by proton nuclear magnetic resonance ( 1 H NMR)-based metabolomics approach. The variation features of the metabolite profiles were studied between varieties and origins of dragon fruit, considering the differences in principal component analysis (PCA). The hierarchical clustering analysis (HCA) based on score values of PCA model was also per- formed to analyze the distance between samples based on metabolites contents. The results of 1 H NMR spectra showed that the CD3OD-D2O extracts quantitatively differ from CD3OD ones. In dragon fruit extracts, 36 me- tabolites were identified. The results demonstrated that the methanol and methanol/water extracted similar compounds with higher intensity in methanol. The metabolic differences among varieties were also shown for CD3OD extracts by comparing both Pareto and UV scaling methods. The big size red fleshed dragon fruit (samples 2 and 3), growing in Israel were clustered similar to that growing in Thailand with the abundance of phenolic compounds. Glucose and fructose were more prominent in the yellow and white fleshed fruit (samples 4 and 5) growing in Israel. To support the obtained results two dimensional 1 H–1 H J-resolved and UHPLC-MS measure- ments were carried out. This research gain novel insights into the field as the first NMR metabolites finger- printing of the major dragon fruit varieties. The correlations between DPPH, CUPRAC, antioxidant and metabolomic properties were also evaluated. The chemical markers associated with varieties of dragon fruit quality and their appearances were identified and can be utilized for the basis of authentication purpose of this fruit.

  • Metal (Mo, W, Ti) Carbide Catalysts: Synthesis and Application as Alternative Catalysts for Dry Reforming of Hydrocarbons—A Review
    • Natalia Czaplicka
    • Andrzej Rogala
    • Izabela Wysocka
    2021 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Dry reforming of hydrocarbons (DRH) is a pro-environmental method for syngas production. It owes its pro-environmental character to the use of carbon dioxide, which is one of the main greenhouse gases. Currently used nickel catalysts on oxide supports suffer from rapid deactivation due to sintering of active metal particles or the deposition of carbon deposits blocking the flow of gases through the reaction tube. In this view, new alternative catalysts are highly sought after. Transition metal carbides (TMCs) can potentially replace traditional nickel catalysts due to their stability and activity in DR processes. The catalytic activity of carbides results from the synthesis-dependent structural properties of carbides. In this respect, this review presents the most important methods of titanium, molybdenum, and tungsten carbide synthesis and the influence of their properties on activity in catalyzing the reaction of methane with carbon dioxide.

  • Metal–Organic Frameworks (MOFs) for Cancer Therapy
    • Mohammad Saeb
    • Navid Rabiee
    • Masoud Mozafari
    • Francis Verpoort
    • Leonid G. Voskressensky
    • Rafael Luque
    2021 Full text Materials

    MOFs exhibit inherent extraordinary features for diverse applications ranging from catalysis, storage, and optics to chemosensory and biomedical science and technology. Several procedures including solvothermal, hydrothermal, mechanochemical, electrochemical, and ultrasound techniques have been used to synthesize MOFs with tailored features. A continued attempt has also been directed towards functionalizing MOFs via “post-synthetic modification” mainly by changing linkers (by altering the type, length, functionality, and charge of the linkers) or node components within the MOF framework. Additionally, efforts are aimed towards manipulating the size and morphology of crystallite domains in the MOFs, which are aimed at enlarging their applications window. Today’s knowledge of artificial intelligence and machine learning has opened new pathways to elaborate multiple nanoporous complex MOFs and nano-MOFs (NMOFs) for advanced theranostic, clinical, imaging, and diagnostic purposes. Successful accumulation of a photosensitizer in cancerous cells was a significant step in cancer therapy. The application of MOFs as advanced materials and systems for cancer therapy is the main scope beyond this perspective. Some challenging aspects and promising features in MOF-based cancer diagnosis and cancer therapy have also been discussed.

  • Metals and metal-binding ligands in wine: Analytical challenges in identification.
    • Magdalena Fabjanowicz
    • Justyna Płotka-Wasylka
    2021 TRENDS IN FOOD SCIENCE & TECHNOLOGY

    Background Due to important role of metals in the vinification process as well as their impact on the human health, their content in this alcoholic beverage has been extensively studied by many researchers. It is already known that speciation of metals determines their toxicity and bioavailability as well as influences their activity. Understanding the chemistry and knowing the structures of metal complexes could have relevant influence on more effective approaches for prevention of some diseases including cancer. Thus, monitoring and studying the metal complexation process, structures of metal complexes present in wine, as well as their stability, is crucial. Scope and approach In this review the main developments in the metal complex identification in wine samples are described. The study emphasizes metal complexes with two ligand groups such as polyphenols and organic acids as a group of compounds well known for their health-beneficial nature. Key findings and conclusions Complexity of the wine matrix related with the presence of numerous organic compounds makes the examination of wine in the context of metal complexes identification a highly challenging task. Metals and metal complexes are present in low concentrations, which can potentially cause interferences during an analytical process. Currently, the most promising technique that can be used for metal complex identification is ESI-MS coupled with separation technique such as liquid chromatography.

  • Metamaterial-Based Sub-Microwave Electromagnetic Field Energy Harvesting System
    • Mikołaj Nowak
    2021 Full text ENERGIES

    This paper presents the comprehensive analysis of the sub-microwave, radio frequency band resonant metastructures’ electromagnetic properties with a particular emphasis on the possibility of their application in energy harvesting systems. Selected structures based on representative topologies of metamaterials have been implemented in the simulation environment. The models have been analyzed and their substitute average electromagnetic parameters (absorption, reflection, transmission and homogenized permeability coefficients) have been determined. On the basis of simulation research, prototypes of electromagnetic field two-dimensional absorbers have been manufactured and verified experimentally in the proposed test system. The absorber has been implemented as a component of the low-cost energy harvesting system with a high-frequency rectifier and a voltage multiplier, obtaining usable DC energy from the electromagnetic field in certain frequency bands. The energy efficiency of the system has been determined and the potential application in energy harvesting technology has been assessed.

  • Method for the correlation coefficient estimation of the bottom echo signal in the shallow water application using interferometric echo sounder
    • Piotr Grall
    • Jacek Marszal
    2021 Full text Vibrations in Physical Systems

    The article presents a new method for the assessment of bottom echo correlation coefficient in the presence of multiple echoes. Bottom correlation coefficient is a parameter that characterizes spatial properties of echo signal. Large variability of the bottom shape or properties (for example caused by the presence of bottom objects) and the presence of the acoustic shadow strongly influence the value of the correlation coefficient. There is a problem, however, in the proper determination of correlation coefficient of the bottom echo when more than one echo is present. In the shallow water application, the echoes coming to the hydroacoustic array from various directions influence the measured value of the correlation coefficient. The method proposed by the authors challenges this issue by applying a subarray processing based on the initial depth estimation. The article presents the preliminary research results and describes the limitations of the proposed method.

  • Methodology for determining the elemental composition, as well as energy and ignition properties of the low-sulfur marine fuels
    • Zbigniew Korczewski
    2021 Full text Combustion Engines

    The key metrological issue of substance and energy balance in research engines is the precise determination of the elemental composition of the applied fuel and its net calorific value. This makes it possible to calculate the amount of heat brought with the fuel into the combustion chamber, as well as the amount and gas composition of the exhaust. However, to fully assess the energy quality of the fuel used, its ignition properties should also be estimated. They determine the combustion kinetics and, consequently, the course of gas pressure alterations and heat release in the cylinder, which have a direct impact on the indicated power and thermal efficiency of the engine. This article presents the methodology for carrying out this type of laboratory tests and their representative results concerning six different low-sulfur marine fuels used to feed marine engines at present. The considerations focus mainly on measurement technology, as well as the measuring apparatus applied today. Additionally some existing metrological difficulties that might be met were shortly described. The laboratory tests in question stand for the first stage of the program of testing a new kind of low-sulfur marine fuels in real operating conditions of a diesel engine, which was carried out at the Department of Ship Power Plants of the Gdańsk University of Technology.

  • Methodology for the Correction of the Spatial Orientation Angles of the Unmanned Aerial Vehicle Using Real Time GNSS, a Shoreline Image and an Electronic Navigational Chart
    • Krzysztof Naus
    • Piotr Szymak
    • Paweł Piskur
    • Maciej Niedziela
    • Aleksander Nowak
    • Pawel Piskur
    2021 Full text ENERGIES

    Undoubtedly, Low-Altitude Unmanned Aerial Vehicles (UAVs) are becoming more common in marine applications. Equipped with a Global Navigation Satellite System (GNSS) Real-Time Kinematic (RTK) receiver for highly accurate positioning, they perform camera and Light Detection and Ranging (LiDAR) measurements. Unfortunately, these measurements may still be subject to large errors-mainly due to the inaccuracy of measurement of the optical axis of the camera or LiDAR sensor. Usually, UAVs use a small and light Inertial Navigation System (INS) with an angle measurement error of up to 0.5 deg. (RMSE). The methodology for spatial orientation angle correction presented in the article allows the reduction of this error even to the level of 0.01 deg. (RMSE). It can be successfully used in coastal and port waters. To determine the corrections, only the Electronic Navigational Chart (ENC) and an image of the coastline are needed.

  • Methodology of Selecting the Optimal Receptor to Create an Electrochemical Immunosensor for Equine Arteritis Virus Protein Detection
    • Mateusz Brodowski
    • Marcin Kowalski
    • Wioleta Białobrzeska
    • Katarzyna Pałka
    • Rafał Walkusz
    • Justyna Roguszczak
    • Tomasz Łęga
    • Marta Sosnowska
    • Małgorzata Biedulska
    • Joanna Kreczko Kurzawa
    • Ewelina Bięga
    • Joanna Wysocka
    • Marta Lisowska
    • Katarzyna Niedźwiedzka
    • Tomasz Lipiński
    • Sabina Żołędowska
    • Dawid Nidzworski
    2021 Full text Chemosensors

    The study reports a methodology of selecting the optimal receptor to create an electrochemical immunosensor for equine arteritis virus (EAV) protein detection. The detection was based on antigen recognition by antibodies immobilized on gold electrodes. Modification steps were controlled by electrochemical impedance spectroscopy and cyclic voltammetry measurements. In order to obtain the impedance immunosensor with the best parameters, seven different receptors complementary to equine arteritis virus protein were used. In order to make the selection, a rapid screening test was carried out to check the sensor’s response to blank, extremely low and high concentrations of target EAV protein, and negative sample: M protein from Streptococcus equi and glycoprotein G from Equid alphaherpesvirus 1. F6 10G receptor showed the best performance.

  • Methods of Determining Pressure Drop in Internal Channels of a Hydraulic Motor
    • Paweł Śliwiński
    • Piotr Patrosz
    2021 Full text ENERGIES

    In this paper, new methods for determining the pressure drop in internal channels of a hydraulic motor are proposed and described. Mathematical models of pressure losses in internal channels have also been described. Experimental tests of the satellite motor were carried out according to one of the proposed methods. The tests were carried out for two liquids, i.e., water and mineral oil. Experimental studies have shown that at a high flow rate in the motor supplied with water the pressure losses are a dozen or so percent greater than in the motor supplied with oil. However, at low flow rates is the inverse, that is, the pressure losses in the motor supplied with water are about ten percent lower than in the motor supplied with oil. The CFD calculation of the pressure drop in the internal channel of the motor was also conducted. It was assumed that holes in the commutation unit plate are placed face to face and that the liquid did not cause changes in the working chambers’ volume. In this way, it has been proven that those simplified assumptions can have up to a 50% difference in relation to the experimental tests.