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Gdańsk University of Technology

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  • Metoda doboru współczynników sztywności podpór mocujących podczas frezowania wielkogabarytowych przedmiotów podatnych z wykorzystaniem sterowania optymalnego w układzie semiaktywnym
    • Krzysztof Kaliński
    • Marek Galewski
    • Michał Mazur
    • Natalia Stawicka-Morawska
    2021

    W pracy zaproponowano nową metodę doboru w trybie on-line współczynników sztywności zamocowania wielkogabarytowego przedmiotu obrabianego do stołu frezarki, bazującą na koncepcji sterowania optymalnego przy energetycznym wskaźniku jakości w układzie we współrzędnych hybrydowych. Jednak znane z poprzednich opracowań autorskich równanie dynamiki wielowymiarowego układu sterowanego sprowadza się w tym przypadku do postaci, gdzie składowymi wektora sygnałów sterujących są chwilowe zmiany wartości współczynników sztywności podpór mocujących przedmiot. Wyznaczone w trybie on-line wartości współczynników sztywności, na bazie symulacji modelu obliczeniowego układu hybrydowego procesu frezowania, można następnie przybliżyć do tych wynikających z uprzedniego cechowania podpór. W proponowanej metodzie wykorzystano ponadto technikę sprzężenia modalnego, oraz zmodyfikowany energetyczny wskaźnik jakości (ZEWJ) uwzględniający energię pochodzącą od przyspieszeń drgań.

  • Metody bezpośrednie wykrywania przyczyn biokorozji
    • Edyta Malinowska-Pańczyk
    2021

    W rozdziale omówiono teoretyczne podstawy oznaczania najważniejszych grup drobnoustrojów powodujących biokorozję

  • METODY IDENTYFIKACJI STANÓW NIEZDATNOŚCI EKSPLOATACYJNEJ ŁOŻYSK TOCZNYCH W OKRĘTOWYCH UKŁADACH NAPĘDOWYCH Z WYKORZYSTANIEM METODY IMPULSÓW UDAROWYCH
    • Konrad Marszałkowski
    2021 Full text Journal of Polish CIMEEAC

    Rozpatrując okrętowe zespoły napędowe z punktu widzenia transmisji energii mechanicznej największym zagrożeniem dla ich niezawodności jest utrata stabilności układu mechanicznego, co zazwyczaj objawia się zwiększeniem amplitudy drgań mechanicznych. Zwiększeniu tych drgań towarzyszy wzrost amplitudy okresowo zmiennych naprężeń wewnętrznych co jest prostą i nieuniknioną drogą do uszkodzenia znajdujących się w tym układzie łożysk. W artykule przybliżono istotę metody impulsu udarowego służącej do diagnostyki łożysk tocznych jako alternatywę do szeroko stosowanej diagnostyki drganiowej.

  • Metrisability of managing of stream-systemic processes
    • Radosław Drozd
    • Jan Piwnik
    2021 Full text Organizacja i Zarządzanie : kwartalnik naukowy

    To achieve the planned goal, in order to properly describe the manufacturing system management, six process stream functions were introduced. Non-dimensional flows of these functions in time can be empirically defined during the manufacturing process. They are interpreted as non-dimensional expenses. Maximum values for these functions in properly-managed processes equal one. Also, a global management function was introduced, being a sum of areas of circle sections delineated by functions of the streams and their respective weights. Stream weights in the manufacturing process signify the processes’ roles and importance in the system. The paper also provides a vector representation of a manufacturing process as a sum of stream vectors with their associated weights.

  • Metrisable assessment of the course of stream‑systemic processes in vector form in industry 4.0
    • Radosław Drozd
    • Radosław Wolniak
    2021 Full text Quality and Quantity

    The goal of this paper is to present an innovative conception how to use metrisable vector structure of a manufacturing process, based on quantitative relations between the activity of input streams, features of the product, and effect of losses; all of which are excellent practical solution for Industry 4.0, and in turn intelligent factories. This solution can be a usefull way in the process of building sustainable organization. A vector representation of manufacturing processes was formulated, one which is based in system engineering. Three manufacturing system state vectors were proposed. These are: input stream vector ϕ ⃗, product features vector ( P) ⃗ which is also referred to as quality vector, and losses vector ( S) ⃗. Scalar, vector, and mixed products of these vectors may form constitutive equations of manufacturing processes. The relations between the vectors ϕ ⃗, ( P) ⃗ ,( S) ⃗ provide a possibility for a metrisable, complex analysis and assessment of a contemporary manufacturing process. The paper shows practical methods for defining the size of the vector values within the process. The demonstrated vector description of stream-systemic processes can also be applied to non-material manufacturing.

  • Mg2+ Doping Effects on the Structural and Dielectric Properties of CaCu3Ti4O12 Ceramics Obtained by Mechanochemical Synthesis
    • Piotr Dulian
    • Wojciech Bąk
    • Mateusz Piz
    • Barbara Garbarz-Glos
    • Olena V. Sachuk
    • Krystyna Wieczorek-Ciurowa
    • Agata Lisińska-Czekaj
    • Dionizy Czekaj
    2021 Full text Materials

    In this study, ceramic CaCu3Ti4O12 (CCTO) and CaCu3−xMgxTi4O12 solid solutions in which 0.1 ≤ x ≤ 0.5 were prepared by the mechanochemical method, realized by a high‐energy ball milling technique. The effects of the Mg2+ ion concentration and sintering time on the dielectric response in the prepared ceramics were investigated and discussed. It was demonstrated that, by the use of a sufficiently high energy of mechanochemical treatment, it is possible to produce a crystalline product after only 2 h of milling the mixture of the oxide substrates. Both the addition of magnesium ions and the longer sintering time of the mechanochemically‐produced ceramics cause excessive grain growth and significantly affect the dielectric properties of the materials. The X‐ray diffraction (XRD) analysis showed that all of the as‐prepared solid solutions, CaCu3−xMgxTi4O12 (0.0 ≤ x ≤ 0.5), regardless of the sintering time, exhibit a cubic perovskite single phase. The dielectric study showed two major contributions associated with the grains and the grain boundaries. The analysis of the electric modules of these ceramics confirmed the occurrence of Maxwell–Wagner type relaxation, which is dependent on the temperature.

  • MgPd2Sb : A Mg-based Heusler-type superconductor
    • Michał Winiarski
    • Gabriel Kuderowicz
    • Karolina Górnicka
    • Leszek Litzbarski
    • Kamila Stolecka
    • Bartlomiej Wiendlocha
    • R.j. Cava
    • Tomasz Klimczuk
    2021 Full text PHYSICAL REVIEW B

    We report the synthesis and physical properties of a full Heusler compound, MgPd2Sb, which we found toshow superconductivity belowTc=2.2K. MgPd2Sb was obtained by a two-step solid-state reaction methodand its purity and cubic crystal structure [Fm-3m,a=6.4523(1) Å] were confirmed by powder x-ray diffrac-tion. Normal and superconducting states were studied by electrical resistivity, magnetic susceptibility, andheat capacity measurements. The results show that MgPd2Sb is a type-II, weak coupling superconductor(λe-p=0.53). The observed pressure dependence ofTc(Tc/p≈–0.23 K/GPa) is one of the strongest reportedfor a superconducting Heusler compound. The electronic structure, phonons, and electron-phonon coupling inMgPd2Sb were theoretically investigated. The obtained results are in agreement with the experiment, confirmingthe electron-phonon coupling mechanism of superconductivity. We compare the superconducting parameters tothose of all reported Heusler-type superconductors.

  • Miasto w kontekście uchwał krajobrazowych
    • Magdalena Rembeza
    2021 Zawód: Architekt

    Krajobraz miejski jest zjawiskiem wizualnym, które oddaje charakter przestrzeni, a także określa jej tożsamość. Niestety, zagraża mu jednak powszechny chaos, przekładający się na negatywny wizerunek miasta. Za jedną z jego najistotniejszych przyczyn uznaje się ogromną liczbę reklam umieszczanych dowolnie w przestrzeni publicznej. Mimo że informacja wizualna stanowi nieodłączny element współczesnego miasta, istnieje głęboka potrzeba regulacji tych interwencji. Wraz z wejściem w życie ustawy gminy uzyskały kompetencje do wprowadzenia uchwały będącej aktem prawa miejscowego w sprawie lokalizacji reklam, obiektów małej architektury oraz ogrodzeń. Jednym z pierwszych miast, które zdecydowało się na sporządzenie i uchwalenie takiego dokumentu była Łódź. Za jej przykładem poszły inne, wśród których szczególnym przypadkiem jest Gdańsk.

  • Microbial and chemical quality assessment of the small rivers entering the South Baltic. Part I: Case study on the watercourses in the Baltic Sea catchment area
    • Emilia Bączkowska
    • Agnieszka Kalinowska
    • Oskar Ronda
    • Katarzyna Jankowska
    • Rafał Bray
    • Bartosz Płóciennik
    • Żaneta Polkowska
    2021 Full text Archives of Environmental Protection

    The area of the Coastal Landscape Park (CLP) due to its location is extremely attractive touristic area. In the summer season, a significant increase in population density is observed, which influences surface water quality. Large numbers of tourists generate an increased amount of municipal wastewater, being treated in local treatment plants and discharged into rivers and streams. The paper presents preliminary research from summer 2016 on three watercourses ending in the Baltic Sea: Piaśnica, Karwianka and Czarna Wda rivers. It is a part of a long-term project conducted in CLP to assess surface waters quality. The scope of research included measurements of in situ parameters (temperature, conductivity, pH, dissolved oxygen). Chemical Oxygen Demand was determined using a spectrophotometer. Ion chromatography was used to determine ions concentrations (including biogenic compounds). Sanitary state of watercourses was assessed based on fecal coliforms abundance, which number was determined by the cultivation method. The determination of microbiological parameters such as: prokaryotic cell abundance expressed as total cells number (TCN), prokaryotic cell biovolume expressed as average cell volume (ACV), the prokaryotic biomass (PB) and prokaryotic cell morphotype diversity was determined using epifluorescence microscopy method. Results showed that water quality of Piaśnica and Czarna Wda rivers were affected by discharged treated wastewater. In the case of Karwianka River, the main pollution source could be surface runoff from fields and unregulated sewage management in this area. The conducted research confirmed the urgent need for better protection of this area to conserve both its ecosystem and value for tourism.

  • Micro-modelling of shear localization during quasi-static confined granular flow in silos using DEM
    • Aleksander Grabowski
    • Michał Nitka
    • Andrzej Tejchman-Konarzewski
    2021 COMPUTERS AND GEOTECHNICS

    The paper deals with the quasi-static confined flow of cohesionless sand in a plane strain model silo with parallel walls and a slowly movable bottom. Numerical modelling was carried out by the discrete element method (DEM) using spheres with contact moments to approximately capture a non-uniform shape of sand particles. Different initial void ratios of sand and silo wall roughness grades were employed. Regular triangular grooves (asperities) with the same inclination and a different height were used to describe the varying wall surface topography. The emphasis was on the formation and evolution of both wall and internal shear zones during sand flow. DEM simulation outcomes were compared with corresponding model experiments and theoretical solutions. In addition, the particle displacements, particle rotations, normal contact forces, void ratios and wall stresses were evaluated. The numerical findings enhance the understanding of shear localization at the grain level during confined flow in silos and its strong impact on the magnitude, distribution and oscillation of wall stresses.

  • Microsphere structure application for supercapacitor in situ temperature monitoring
    • Paulina Listewnik
    • Mikhael Bechelany
    • Małgorzata Szczerska
    2021 Full text SMART MATERIALS & STRUCTURES

    Constant, real-time temperature monitoring of the supercapacitors for efficient energy usage is in high demand and seems to be crucial for further development of those elements. A fiber-optic sensor can be an effective optoelectronic device dedicated for in-situ temperature monitoring of supercapacitors. In this work, the application of the fiber-optic microstrucutre with thin zinc oxide (ZnO) coating fabricated in the atomic layer deposition process applied as a temperature sensor is reported. Such a structure was integrated with supercapacitors and used for the temperature measurements. Described sensors are built with the utility of the standard optical telecommunication fibers. The inner temperature of the supercapacitor was investigated in the range extending from 30 °C to 90 °C with a resolution equal to 5 °C. The sensitivity of temperature measurement is about 109.6 nW °C−1. The fitting of the sensor was achieved with a correlation coefficient R2 = 0.97.

  • Microstructural Design of Ba0.5La0.5Co0.5Fe0.5O3 Perovskite Ceramics
    • Daria Gierszewska
    • Iga Szpunar
    • Francis Oseko
    • Joanna Pośpiech
    • Małgorzata Nadolska
    • Martyna Pieragowska
    • Karolina Reniecka
    • Kinga Waniek
    • Karol Leszczyński
    • Aleksandra Mielewczyk-Gryń
    • Maria Gazda
    • Sebastian Wachowski
    2021 Full text Materials

    Ba0.5La0.5Co0.5Fe0.5O3 was synthesized in the solid-state reaction route. The influence of ball milling parameters (such as milling media size, angular velocity, and time), pelletizing pressure, and annealing parameters on the microstructure was studied. The grain size distribution and density or specific surface area changes were investigated in each approach while the individual parameters were changed. The evaluation of BLCF synthesis parameters enables tailoring the microstructure to various applications. It was observed that with lowering the size of milling balls and increasing the angular velocity the material will be porous and thus more appropriate as electrode material in proton ceramic fuel cell or electrolyzer. An increase of time, balls diameter, and/or angular velocity of milling enables one to densify the material in case of membrane application in, e.g., as a gas sensor. The significant influence on densification has also annealing temperature increase. Applying 1200 C during annealing leads to dense material, while at 1100 C shows visible porosity of the product. In this work, we present the results of the BLCF synthesis parameters change allowing the selection of appropriate parameter values depending on the further application as PCCs.

  • Microstructure and mechanical properties of laser surface-treated Ti13nb13zr alloy with MWCNTs coatings
    • Beata Majkowska-Marzec
    • Joanna Sypniewska
    2021 Full text Advances in Materials Science

    Laser surface modification of titanium alloys is one of the main methods of improving the properties of titanium alloys used in implantology. This study investigates the microstructural morphology of a laser-modified surface layer on a Ti13Nb13Zr alloy with and without a carbon nanotube coating deposited by electrophoretic deposition. Laser modification was performed for samples with and without carbon nanotube coating for two different laser powers of 800 W and 900 W and for different scan rates: 3 mm/s or 6 mm/s at 25 Hz, and the pulse duration was 2.25 ms or 3.25 ms. A scanning electron microscope SEM was used to evaluate the surface structure of the modified samples. To observe the heat-affected zones of the individual samples, metallographic samples were taken and observed under an optical microscope. Surface wettability tests were performed using a goniometer. A surface roughness test using a profilograph and a nanoindentation test by NanoTest™ Vantage was also performed. Observations of the microstructure allowed to state that for higher laser powers the surfaces of the samples are more homogeneous without defects, while for lower laser powers the path of the laser beam is clearer and more regular. Examination of the microstructure of the cross-sections indicated that the samples on which the carbon nanotube coating was deposited are characterized by a wider heat affected zone, and for the samples modified at 800 W and a feed rate of 3 mm/s the widest heat affected zone is observed. The wettability tests revealed that all the samples exhibit hydrophilic surfaces and the samples with deposited carbon nanotube coating increase it further. Surface roughness testing showed a significant increase in Ra for the laser-modified samples, and the presence of carbon nanotubes further increased this value. Nanoindentation studies showed that the laser modification and the presence of carbon coating improved the mechanical properties of the samples due to their strength.

  • Microstructure and Properties of Electroless Ni-P/Si3N4 Nanocomposite Coatings Deposited on the AW-7075 Aluminum Alloy
    • Kazimierz Czapczyk
    • Paweł Zawadzki
    • Natalia Wierzbicka
    • Rafał Talar
    2021 Full text Materials

    The article presents the results of mechanical and tribological tests of Ni-P/Si3N4 nanocomposite coatings deposited on the AW-7075 aluminum alloy using the chemical reduction method. The influence of the chemical composition on the Vickers microhardness determined by the DSI method was examined. The nanocomposite layers were made of Si3N4 silicon nitride in a polydisperse powder with a particle size ranging from 20 to 25 nm. The influence of the content of the dispersion layer material on the adhesion to the substrate was analyzed. The abrasive wear was tested and determined in the reciprocating motion using the “ball-on-flat” method. The surface topography was examined by the contact method with the use of a profilometer. Based on the obtained test results, it was found that the Ni-P/Si3N4 layers produced in the bath with the Si3N4 nanoparticle content in the amount of 2 g/dm3 are more resistant to wear and show greater adhesion than the Ni-P/Si3N4 layers deposited in the bath with 5 g/dm3 of the dispersion phase. NiP/Si3N4 layers provide protection against abrasive wear under various loads and environmental conditions.

  • Międzynarodowy Projekt "Walizka". Galeria R+ Akademia Sztuki w Szczecinie
    • Dominika Krechowicz
    2021

    Projekt "Walizka", koncepcja: prof. dr hab. Zbigniew Szot Uniwersytet Artystyczny w Poznaniu, Wydział Malarstwa i Rysunku. W projekcie wzięło udział 23 artystów z Polski oraz z Czech, Niemiec, Gruzji I Japonii. Koncepcja projektu dotyczy szeroko pojętego tematu podróży. W obecnych czasach zagrożenia COVID-19 słowo „podróż” zaczyna nabierać zupełnie innego znaczenia. Żyjąc i tworząc w izolacji od wielu miesięcy, została stworzona wspólnie autonomiczna kolekcja prac, dedykowanych tylko tej walizce, która teraz jest wysyłana w podróż. Prace i walizka stanowią nierozłączną całość. Koncepcją projektu jest zaprezentowanie prac w wybranych miejscach oraz pozostawienie swojego znaku na wieku walizki. Wystawa została zaprezentowana w terminie 17-28.05.2021 w Galerii R+ w Akademii Sztuki w Szczecinie. Adres: plac Orła Białego 2, 70-562 Szczecin kurator wystawy: prof.dr hab.Zbigniew Szot

  • Międzynarodowy Projekt Walizka. Wystawa w Galerii Feininger. Trzebiatów
    • Dominika Krechowicz
    2021

    Projekt "Walizka", koncepcja: prof. dr hab. Zbigniew Szot Uniwersytet Artystyczny w Poznaniu, Wydział Malarstwa i Rysunku. W projekcie wzięło udział 23 artystów z Polski oraz z Czech, Niemiec, Gruzji I Japonii. Koncepcja projektu dotyczy szeroko pojętego tematu podróży. W obecnych czasach zagrożenia COVID-19 słowo „podróż” zaczyna nabierać zupełnie innego znaczenia. Żyjąc i tworząc w izolacji od wielu miesięcy, została stworzona wspólnie autonomiczna kolekcja prac, dedykowanych tylko tej walizce, która teraz jest wysyłana w podróż. Prace i walizka stanowią nierozłączną całość. Koncepcją projektu jest zaprezentowanie prac w wybranych miejscach oraz pozostawienie swojego znaku na wieku walizki. Wystawa została zaprezentowana w terminie 3 - 28 lipca 2021 w Galerii Feininger, w Trzebiatowskim Ośrodku Kultury w Trzebiatowie kurator wystawy: prof.dr hab.Zbigniew Szot

  • Migration of container terminals as their natural process of evolution: Case study of Gdańsk and Gdynia ports
    • Karolina Krośnicka
    2021 Full text Journal of Transport Geography

    The paper proposes a theoretical model of container terminals and container port development, based on the life cycle theory, threshold theory and catastrophe theory, and in references to Kuznets' swings (interpreted as waves of infrastructural investments), and Kondratiev long economic waves. The aim of this model is to explain the development process of a container terminal and a port within one technological generation, as well as in intergenerational configuration, and relate it to the migration process of container terminals in the scale of a port-city urban area. Then, the applicability of this model was checked in the case of the container ports in Gdynia and Gdańsk (Poland). The analysed evolution process of ports of Gdynia and Gdańsk conforms with the proposed theoretical model, proving that the migration of container terminals within these ports is a part of their natural process of evolution, being a consequence of their threshold development and location splitting. Considering the physical location of development investments within the container ports of Gdańsk and Gdynia, it was noticed that there are two basic directions of migration of container terminals. One is the migration of the port's main container activity (core terminal or terminals), being a result of a generational change taking place after overcoming the maturity point. The second type of migration is connected with dispersion of port development investments in the increasingly distant port hinterland, caused by the need of the life extension of terminals within one technological generation. In an analogy to the processes of development of living organisms, we can treat the migration of terminal outsourced functions as a “vegetative” increase, being an attempt to extend the life of the terminal, while the migration of the core terminal within the port area (erecting a new generation terminal) can be treated as “generative” growth.

  • Mild poikilocapnic hypoxia increases very low frequency haemoglobin oxygenation oscillations in prefrontal cortex
    • Agnieszka Gruszecka
    • Monika Waskow
    • Marta A. Malkiewicz
    • J Neary
    • Jyotpal Singh
    • Taylor Teckchandani
    • Gregory Kratzig
    • Magdalena Wszedybyl-Winklewska
    • Andrzej F. Frydrychowski
    • Jacek Rumiński
    • Natalia Głowacka
    • Piotr Lass
    • Pawel Winklewski
    • Marcin Gruszecki
    2021 Full text BIOLOGICAL RESEARCH

    Background: The aim of the study was to investigate the effect of mild cerebral hypoxia on haemoglobin oxygenation(HbO2), cerebrospinal fluid dynamics and cardiovascular physiology. To achieve this goal, four signals were recorded simultaneously: blood pressure, heart rate / electrocardiogram, HbO2 from right hemisphere and changes of subarachnoid space (SAS) width from left hemisphere. Signals were registered from 30 healthy, young participants (2 females and 28 males, body mass index = 24.5 ± 2.3 kg/m2, age 30.8 ± 13.4 years). Results: We analysed the recorded signals using wavelet transform and phase coherence. We demonstrated for the first time that in healthy subjects exposed to mild poikilokapnic hypoxia there were increases in very low frequency HbO2 oscillations (< 0.052 Hz) in prefrontal cortex. Additionally, SAS fluctuation diminished in the whole frequency range which could be explained by brain oedema. Conclusions: Consequently the study provides insight into mechanisms governing brain response to a mild hypoxic challenge. Our study supports the notion that HbO2 and SAS width monitoring might be beneficial for patients with acute lung disease.

  • Mild X-linked Alport syndrome due to the COL4A5 G624D variant originating in the Middle Ages is predominant in Central/East Europe and causes kidney failure in midlife
    • Aleksandra M. Żurowska
    • Olga Bielska
    • Patrycja Daca-Roszak
    • Maciej Jankowski
    • Maria Szczepańska
    • Dagmara Roszkowska-Bjanid
    • Elżbieta Kuźma-Mroczkowska
    • Małgorzata Pańczyk-Tomaszewska
    • Anna Moczulska
    • Dorota Drożdż
    • Despina Hadjipanagi
    • Constantinos Deltas
    • Danuta Ostalska-Nowicka
    • Alina Rabiega
    • Janina Taraszkiewicz
    • Katarzyna Taranta-Janusz
    • Anna Wieczorkiewicz-Plaza
    • Katarzyna Jobs
    • Judyta Mews
    • Kinga Musiał
    • Anna Jakubowska
    • Hanna Nosek
    • Anna E. Jander
    • Constantina Koutsofti
    • Anna Stanisławska-Sachadyn
    • Dominka Kuleszo
    • Ewa Ziętkiewicz
    • Beata S. Lipska-Ziętkiewicz
    2021 Full text KIDNEY INTERNATIONAL

    A study of 269 children enrolled into a National Registry for children with persistent glomerular hematuria identified 131 individuals with genetically confirmed X-linked Alport Syndrome. A single variant c.1871G>A p.Gly624Asp (G624D) in COL4A5 was predominant and accounted for 39% of Xlinked Alport Syndrome in unrelated Polish families (44 of 113). To evaluate its origins, the genetic variation in a 2.79 Mb segment encompassing the COL4A5 locus on chromosome X was assessed. All G624D alleles were found on the same rare haplotype background, indicating a founder effect dating back to the 12-13th century. The phenotypic data of 131 children with X-linked Alport Syndrome and their 195 affected adult relatives revealed that the G624D variant was associated with a significantly milder clinical course in comparison to other pathogenic COL4A5 variants. Furthermore the clinical course of this genetically uniform cohort was milder than that observed in individuals with other COL4A5 missense mutations. In spite of the benign clinical manifestation throughout childhood and early adulthood, the G624D variant confers significant risk for both kidney failure and deafness in males, albeit 20-30 years later than that observed in individuals with other COL4A5 pathogenic variants (50% cumulative risk of starting dialysis at 54 years (95% confidence interval: 50-62) v. 26 years (95% confidence interval: 22-30)). Thus, males with G624D are candidates for existing and emerging therapies for Alport Syndrome.

  • Mini-Cave Automatic Virtual Environment Application in Security, Safety, and Defence Studies
    • Małgorzata Gawlik-Kobylińska
    • Paweł Maciejewski
    • Jacek Lebiedź
    2021

    The aim of the article is to analyse the use of mini-Cave Automatic Virtual Reality Environment (mini-CAVE) in academic studies on security, safety, and defence. The literature review based on Web of Science database and the case study of the War Studies University research activities indicated the mini-CAVE can be used in two areas as a research infrastructure and as a didactic tool. It can be concluded that due to the development of virtual reality worlds, the application of the mini-CAVE supports research and didactics activities, specifically in creating 3D scenarios for teaching concepts and processes, and simulating situations related to saving life and health.

  • Minichannel and minigap classification criteria based on the aspect ratio of the minigeometry: A numerical study
    • Paweł Dąbrowski
    • Ritunesh Kumar
    2021 Full text INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER

    A detailed numerical investigation has been carried out to analyze the diabatic flow distribution and velocity profile in 18 minigeometries with various aspect ratios for V-type and I-type flow configurations (for 36 cases) assuming ethanol as a working fluid. The aim of the study is to distinguish the value of the aspect ratio for which the flow in minigeometry starts to be two-dimensional (minigap). Cases with a constant Reynolds number of 4167 (variable mass flow rate) were compared. The normalized velocity profiles over the normalized width of the minigeometry acquired from the simulation have been compared with the theoretically calculated profiles based on the one-seventh power-law and turbulent flow theory. The results show that the one-seventh power-law velocity profiles are not consistent with the profiles simulated at an aspect ratio greater than 7. A new correlation for normalized velocity profile incorporating aspect ratio of the minigeometry for minigaps has been proposed. The conclusions are independent of the geometry depth, working fluid, and flow configuration.

  • Minimizing Greenhouse Gas Emissions From Ships Using a Pareto Multi-Objective Optimization Approach
    • Zygfryd Domachowski
    2021 Full text Polish Maritime Research

    To confront climate change, decarbonization strategies must change the global economy. According to statements made as part of the European Green Deal, maritime transport should also become drastically less polluting. As a result, the price of transport must reflect the impact it has on the environment and on health. In such a framework, the purpose of this paper is to suggest a novel method for minimizing emissions from ships, based on so-called Pareto multi-objective optimization. For a given voyage by a ship, the problem is to minimize emissions on the one hand and minimize fuel consumption or passage time on the other. Minimizing emissions is considered as the preferred objective. Therefore, the objective of minimizing fuel consumption or passage time needs to be reformulated as a constraint. Solving such a problem consists of finding most favourable path and speed for the ship and satisfying the optimization criteria. Relatively new systems such as hybrid diesel–electric systems have the potential to offer significant emissions benefits. A hybrid power supply utilizes the maximum efficiency of the direct mechanical drive and the flexibility of a combination of combustion power from the prime mover and stored power from energy storage from an electrical supply, at part load and overload. A new report by the American Bureau of Shipping suggests that maritime transport is likely to meet the International Maritime Organization’s target by 2030, solely by using current technology and operational measures. However, this would not be enough to attain the target of reducing CO2 emissions by 2050 by at least 50% compared to 2008. New technologies and operational methods must be applied.

  • Mining inconsistent emotion recognition results with the multidimensional model
    • Agnieszka Landowska
    • Teresa Zawadzka
    • Michal Zawadzki
    2021 Full text IEEE Access

    The paper deals with the challenge of inconsistency in multichannel emotion recognition. The focus of the paper is to explore factors that might influence the inconsistency. The paper reports an experiment that used multi-camera facial expression analysis with multiple recognition systems. The data were analyzed using a multidimensional approach and data mining techniques. The study allowed us to explore camera location, occlusions and algorithm factors in the late fusion of emotion recognition results. We proposed to use a multidimensional data model for mining the various interdependencies between the factors of inconsistency. The study allowed the exploration of challenges in multichannel emotion recognition. It was achieved by comparing the consistency of obtained emotions and identification of rules determining conditions when the obtained emotions are consistent. However, the main novelty of the paper is the method of mining the inconsistencies. The study might be interesting both for researchers dealing with integration in emotion recognition, as well as for practitioners who use automatic emotion analysis software and expect to get valid results.

  • Mispronunciation Detection in Non-Native (L2) English with Uncertainty Modeling
    • Daniel Korzekwa
    • Jaime Lorenzo-trueba
    • Szymon Zaporowski
    • Shira Calamaro
    • Thomas Drugman
    • Bożena Kostek
    2021

    A common approach to the automatic detection of mispronunciation in language learning is to recognize the phonemes produced by a student and compare it to the expected pronunciation of a native speaker. This approach makes two simplifying assumptions: a) phonemes can be recognized from speech with high accuracy, b) there is a single correct way for a sentence to be pronounced. These assumptions do not always hold, which can result in a significant amount of false mispronunciation alarms. We propose a novel approach to overcome this problem based on two principles: a) taking into account uncertainty in the automatic phoneme recognition step, b) accounting for the fact that there may be multiple valid pronunciations. We evaluate the model on non-native (L2) English speech of German, Italian and Polish speakers, where it is shown to increase the precision of detecting mispronunciations by up to 18% (relative) compared to the common approach.

  • Mitigating the seismic pounding of multi-story buildings in series using linear and nonlinear fluid viscous dampers
    • Hytham Elwardany
    • Robert Jankowski
    • Ayman Seleemah
    2021 Full text Archives of Civil and Mechanical Engineering

    Seismic-induced pounding between adjacent buildings may have serious consequences, ranging from minor damage up to total collapse. Therefore, researchers try to mitigate the pounding problem using different methods, such as coupling the adjacent buildings with stiff beams, connecting them by using viscoelastic links, and installing damping devices in each building individually. In the current paper, the effect of using linear and nonlinear fluid viscous dampers to mitigate the mutual pounding between a series of structures is investigated. Nonlinear finite element analysis of a series of adjacent steel buildings equipped with damping devices was conducted. Contact surfaces with both contactor and target were used to model the mutual pounding. The results indicate that the use of linear or nonlinear dampers leads to the significant reduction in the response of adjacent buildings in series. Moreover, the substantial improvement of the performance of buildings has been observed for almost all stories. From the design point of view, it is concluded that dampers implemented in adjacent buildings should be designed to resist maximum force of 6.20 or 1.90times the design independent force in the case of using linear or nonlinear fluid viscous dampers, respectively. Also, designers should pay attention to the design of the structural elements surrounding dampers because considerable forces due to pounding may occur in the dampers at the maximum displaced position of the structure.

  • Mitigation effect of face shield to reduce SARS-CoV-2 airborne transmission risk: Preliminary simulations based on computed tomography
    • Dmitry Tretiakov
    • Krzysztof Tesch
    • Andrzej Skorek
    • Dmitry Tretiakow
    2021 Full text ENVIRONMENTAL RESEARCH

    We aimed to develop a model to quantitatively assess the potential effectiveness of face shield (visor) in reducing airborne transmission risk of the novel coronavirus SARS-CoV-2 during the current COVID-19 pandemic using the computational fluid dynamics (CFD) method. The studies with and without face shield in both an infected and healthy person have been considered in indoor environment simulation. In addition to the influence of the face shield and the synchronization of the breathing process while using the device, we also simulated the effect of small air movements on the SARS-CoV-2 infection rate (outdoor environment simulation). The contact with infectious particles in the case without a face shield was 12–20 s (s), in the presence of at least one person who was positive for SARS-CoV-2. If the infected person wore a face shield, no contact with contaminated air was observed during the entire simulation time (80 s). The time of contact with contaminated air (infection time) decreases to about 11 s when the surrounding air is still and begins to move at a low speed. Qualitative dif­ ferences between simulations performed on the patients with and without the face shield are clearly visible. The maximum prevention of contagion is probably a consequence of wearing a face shield by an infected person. Our results suggest that it is possible to determine contact with air contaminated by SARS-CoV-2 using the CFD method under realistic conditions for virtually any situation and configuration. The proposed method is probably the fastest and most reliable among those based on CFD-based techniques.

  • Mitochondrial DNA copy number and trimethylamine levels in the blood: New insights on cardiovascular disease biomarkers
    • Laura Bordoni
    • Irene Petracci
    • Iwona Pelikant-Malecka
    • Adrianna Radulska
    • Marco Piangerelli
    • Joanna J. Samulak
    • Lukasz Lewicki
    • Leszek Kalinowski
    • Rosita Gabbianelli
    • Robert A. Olek
    2021 Full text FASEB JOURNAL

    Among cardiovascular disease (CVD) biomarkers, the mitochondrial DNA copy number (mtDNAcn) is a promising candidate. A growing attention has been also dedicated to trimethylamine-N-oxide (TMAO), an oxidative derivative of the gut metabolite trimethylamine (TMA). With the aim to identify biomarkers predictive of CVD, we investigated TMA, TMAO, and mtDNAcn in a population of 389 coronary artery disease (CAD) patients and 151 healthy controls, in association with estab-lished risk factors for CVD (sex, age, hypertension, smoking, diabetes, glomerular filtration rate [GFR]) and troponin, an established marker of CAD. MtDNAcn was significantly lower in CAD patients; it correlates with GFR and TMA, but not with TMAO. A biomarker including mtDNAcn, sex, and hypertension (but neither TMA nor TMAO) emerged as a good predictor of CAD. Our findings support the mtD-NAcn as a promising plastic biomarker, useful to monitor the exposure to risk factors and the efficacy of preventive interventions for a personalized CAD risk reduction.

  • Mn-Co spinel coatings on Crofer 22 APU by electrophoretic deposition: Up scaling, performance in SOFC stack at 850 °C and compositional modifications
    • A Sabato
    • E Zanchi
    • Sebastian Molin
    • Grzegorz Cempura
    • H. Javed
    • K. Herbrig
    • C. Walter
    • A Boccaccini
    • Federico Smeacetto
    2021 JOURNAL OF THE EUROPEAN CERAMIC SOCIETY

    Ceramic coatings for metallic interconnects play a key role in limiting corrosion and chromium evaporation in solid oxide cells. This study presents the upscaling of the electrophoretic deposition (EPD) technique to process Mn-Co spinels on real-dimension Crofer 22 APU interconnects and the test in a SOFC stack. Area specific resistance of long-term test conducted for 5000 h at 850 °C demonstrated that two-steps sintering has a significant influence on the coating performance; an area specific resistance degradation rate of 0.5 mΩ cm2 kh−1 is recorded. Stack test, operated in fuel cell mode at 850 °C for 3000 h under application of 227 mA/cm², including 5 thermal cycles, demonstrated the effectiveness of the electrophoretically deposited Mn-Co spinel in limiting the oxide scale growth on the Crofer 22 APU. An advanced post mortem investigation showed the effectiveness of the EPD ceramic coating, even when considering different and complex surfaces of the Crofer 22 APU.

  • Mobile Gas Chromatographs Coupled with Mass and Ion Mobility Spectrometers and their Applications
    • Zygfryd Witkiewicz
    • Waldemar Wardencki
    2021 Full text Ecological Chemistry and Engineering S - Chemia i Inżynieria Ekologiczna S

    The articles describes the developments un combining of mass and ion mobility spectrometers (MS, IMS0 with miniature gas chromatographs (GC). The examples of applications of miniaturised GC-MS and GC-IMS devices are presented.

  • MobileNet family tailored for Raspberry Pi
    • Wojciech Glegoła
    • Aleksandra Karpus
    • Adam Przybyłek
    2021 Full text Procedia Computer Science

    With the advances in systems-on-a-chip technologies, there is a growing demand to deploy intelligent vision systems on low-cost microcomputers. To address this challenge, much of the recent research has focused on reducing the model size and computational complexity of contemporary convolutional neural networks (CNNs). The state-of-the-art lightweight CNN is MobileNetV3. However, it was designed to achieve a good trade-off between accuracy and latency on a single large core of a Google Pixel 1 smartphone. Accordingly, MobileNetV3 is not optimized for platforms with different hardware characteristics and its predecessors may perform better for a given target platform. The aim of this paper is twofold: 1) to analyze the performance of different compact CNNs on Raspberry Pi 4; 2) to manually adapted the most promising models to better utilize the Raspberry Pi 4 hardware. After exploring a number of modifications, we present a new CNN architecture, namely MobileNetV3-Small-Pi, which is 36% faster and slightly more accurate on ImageNet classification compared to the baseline MobileNetV3-Small.

  • Moda jako wartość konsumencka - eksplikacja zagadnienia
    • Anna Dembicka
    2021 Full text Problemy Jakości

    Cel: Celem artykułu jest przedstawienie problematyki mody jako propozycji wartości dla klienta. Realizacja niniejszego celu wymagała uszczegółowionej eksplikacji zjawiska mody. W publikacji zdefiniowaniu poddano mechanizm działania mody, istotę trendu mody, jak również omówiono główne perspektywy analizy mody oraz aktualne nurty badań nad modą. Projekt badania/metodyka badawcza/koncepcja: W pracy wykorzystano metodę krytycznej analizy literatury przedmiotu, mającej na celu identyfikację istotnych dla tematu zagadnień, metodę syntezy oraz wnioskowania logicznego i na ich podstawie podjęto próbę konsolidacji dystynktywnej, statusowej i ekspresywnej roli mody, stanowiącej wartość dla klienta. Interdyscyplinarność zjawiska mody wpłynęła na charakter doboru literatury. Artykuł ma charakter przeglądowy. Wyniki/wnioski: Poznanie psychologicznych, socjologicznych i ekonomicznych źródeł mody oraz motywów wpływających na uleganie jej mechanizmowi umożliwia pełniejsze zrozumienie oczekiwań nabywcy towarów i usług poddawanych odziaływaniu trendów mody i tworzenie konkurencyjnych ofert sprzedażowych. Ograniczenia: Ujmowanie mody jako wartości nabywczej wymaga bardziej pogłębionych analiz, głównie ze względu na wielokontekstowość zjawiska mody. Kierunkiem przyszłych badań autorki będzie ujawnienie zależności pomiędzy kompatybilną triadą wartości dla klienta w przemyśle jachtowym: modą, zabawą i estetyką. Zastosowanie praktyczne: Niniejsze opracowanie stanowić może swoiste kompendium analiz wykorzystywanych w strategiach marketingu zróżnicowanego oferentów dóbr luksusowych. Oryginalność/wartość poznawcza: Artykuł opisuje zjawisko mody z perspektywy zachowań konsumenckich, ujawniając równocześnie uniwersalne spektrum jej charakterystyki. Zdaniem autorki weryfikacja znaczenia mody, w zróżnicowanych pod względem oferty sprzedażowej sektorach, sprzyja dywersyfikacji i porządkowaniu wiedzy na jej temat.

  • Model obliczania kosztu cyklu życia obiektu na przykładzie budynku mieszkalnego jednorodzinnego
    • Adam Kristowski
    • Beata Grzyl
    • Marcin Szczepański
    • Anna Jakubczyk-Gałczyńska
    2021 Przegląd Budowlany

    W artykule przedstawiono model obliczania kosztu cyklu życia budynku mieszkalnego jednorodzinnego oraz wskazano możliwości ograniczenia wydatków związanych z jego użytkowaniem w okresie trzydziestu lat. Celem prezentowanej analizy rachunku kosztu cyklu życia jest porównanie i ocena kosztów nabycia i użytkowania domu realizowanego według alternatywnych technologii z uwzględnieniem przyjętych rozwiązań w zakresie pozyskania energii, wykorzystanych materiałów, systemów grzewczych i wentylacji. Otrzymane rezultaty wskazują na korzyści płynące z wykorzystania w praktyce algorytmu przedstawionego w artykule.

  • Model-Based Adaptive Machine Learning Approach in Concrete Mix Design
    • Patryk Ziółkowski
    • Maciej Niedostatkiewicz
    • Shao-Bo Kang
    2021 Full text Materials

    Concrete mix design is one of the most critical issues in concrete technology. This process aims to create a concrete mix which helps deliver concrete with desired features and quality. Contemporary requirements for concrete concern not only its structural properties, but also increasingly its production process and environmental friendliness, forcing concrete producers to use both chemically and technologically complex concrete mixtures. The concrete mix design methods currently used in engineering practice are joint analytical and laboratory procedures derived from the Three Equation Method and do not perform well enough for the needs of modern concrete technology. This often causes difficulties in predicting the final properties of the designed mix and leads to precautionary oversizing of concrete properties for fear of not providing the required parameters. A new approach that would make it possible to predict the newly designed concrete mix properties is highly desirable. The answer to this challenge can be methods based on machine learning, which have been intensively developed in recent years, especially in predicting concrete compressive strength. Machine learning-based methods have been more or less successful in predicting concrete compressive strength, but they do not reflect well the variability that characterises the currently used concrete mixes. A new adaptive solution that allows estimating concrete compressive strength on the basis of the concrete mix main ingredient composition by including two observations for a given batch of concrete is proposed herein. In presented study, a machine learning model was built with a deep neural network architecture, trained on an extensive database of concrete recipes, and translated into a mathematical formula. Testing on four concrete mix recipes was performed, which were calculated according to contemporary design methods (Bolomey and Fuller method), and a comparative analysis was conducted. It was found out that the new algorithm performs significantly better than that without adaptive features trained on the same dataset. The presented algorithm can be used as a concrete strength checking tool for the concrete mix design process.

  • Modeling an Industrial Revolution: How to Manage Large-Scale, Complex IoT Ecosystems?
    • Geza Kulcsar
    • Pal Varga
    • Marek Tatara
    • Federico Montori
    • Michel A. Inigo
    • Gianvito Urgese
    • Paolo Azzoni
    2021 Full text

    Advancements around the modern digital industry gave birth to a number of closely interrelated concepts: in the age of the Internet of Things (IoT), System of Systems (SoS), Cyber-Physical Systems (CPS), Digital Twins and the fourth industrial revolution, everything revolves around the issue of designing well-understood, sound and secure complex systems while providing maximum flexibility, autonomy and dynamics. The aim of the paper is to present a concise overview of a comprehensive conceptual framework for integrated modeling and management of industrial IoT architectures, supported by actual evidence from the Arrowhead Tools project; in particular, we adopt a three-dimensional projection of our complex engineering space, from modeling the engineering process to SoS design and deployment. In particular, we start from modeling principles of the the engineering process itself. Then, we present a design-time SoS representation along with a toolchain concept aiding SoS design and deployment. This brings us to reasoning about what potential workflows are thinkable for specifying comprehensive toolchains along with their data exchange interfaces. We also discuss the potential of aligning our vision with RAMI4.0, as well as the utilization perspectives for real-life engineering use-cases.

  • Modeling and Evaluation of Electric Treeing Phenomena in Polymeric Cable Insulation
    • Qasim Khan
    • Shady S. Refaat
    • Haitham Abu-Rub
    • Hamid Toliyat
    • Marek Olesz
    2021

    This paper investigates the treeing phenomenon in polymeric materials such as crosslinked polyethylene (XLPE) that is widely used in medium and high voltage power cables as primary insulation. The modeling of electrical tree growth in the insulation from its initiation to breakdown is significant research work that illustrates the discharge dynamics and its impact on aging process in polymeric insulation. This study utilizes pulse sequence analysis (PSA) mapping and phase-resolved partial discharge (PRPD) pattern to model the tree growth and its correlation with the aging in the XLPE samples. The applied electric stress magnitude as a crucial treeing aspect is utilized to comprehend treeing and its relationship with insulation degradation. The tree mapping and plots exemplify and characterize treeing stages to work as a reliable diagnostic tool to determine aging in solid insulation.

  • Modeling of Electrified Transportation Systems Featuring Multiple Vehicles and Complex Power Supply Layout
    • Aleksander Jakubowski
    • Leszek Jarzębowicz
    • Mikołaj Bartłomiejczyk
    • Jacek Skibicki
    • Sławomir Judek
    • Andrzej Wilk
    • Mateusz Płonka
    2021 Full text ENERGIES

    The paper proposes a novel approach to modeling electrified transportation systems. The proposed solution reflects the mechanical dynamics of vehicles as well as the distribution and losses of electric supply. Moreover, energy conversion losses between the mechanical and electrical subsystems and their bilateral influences are included. Such a complete model makes it possible to replicate, e.g., the impact of voltage drops on vehicle acceleration or the necessity of partial disposal of regenerative braking energy due to temporary lack of power transmission capability. The modeling methodology uses a flexible twin data-bus structure, which poses no limitation on the number of vehicles and enables modeling complex traction power supply structures. The proposed solution is suitable for various electrified transportation systems including suburban and urban systems. The modeling methodology is applicable i.a. to Matlab/Simulink, which makes it broadly available and customizable, and provides short computation time. The applicability and accuracy of the method were verified by comparing simulation and measurement results on an exemplary trolleybus system operating in Pilsen, Czech Republic. Simulation of daily operation of an area including four supply sections and maximal simultaneous number of nine vehicles showed a good conformance with the measured data, with the difference in the total consumed energy not exceeding 5%.

  • Modeling of Passive and Forced Convection Heat Transfer in Channels with Rib Turbulators
    • Jan Stąsiek
    • Adam Stąsiek
    • Marek Szkodo
    2021 Full text ENERGIES

    The main goal of the research presented in this paper was the experimental and numerical analysis of heat enhancement and aerodynamic phenomena during air flow in a channel equipped with flow turbulators in the form of properly configured ribs. The use of ribs intensifies the heat transfer and at the same time increases not only the flow resistance but also the energy costs. Therefore, designing modern heat exchangers with optimal thermal and flow parameters requires the knowledge of the theory of heat exchangers as well as measurement methods and numerical calculations. Bearing in mind the above, the liquid crystal techniques (LCT), particle image velocimetry (PIV) and digital image processing (DIP) for temperature, velocity, friction factor and heat transfer coefficient measurements are presented herein. These three optical tools (using desktop computers) create an extremely powerful and advanced measuring technique that has not been available anywhere before. Brief histories of these measurement methods and techniques are discussed and some examples are presented. In order to assess and select the value of the measurement technique, local and average distributions of Nusselt numbers (in the measurement section) obtained by the transit analysis method on the inter-rib regions of a plate coated by thermochromics liquid crystal and heated by air as an alternative to the steady-state analysis. In the parallel, numerical calculation was performed with the use of the ANSYS Fluent software code and supported by laser anemometrycomputed turbulence intensity of air flow. Comparison of the Nusselt number distributions was determined by three methods, i.e., steady state, the transient method and CFD simulation. Up to three-fold enhancement of the local heat transfer capability was observed. Failure to take into account the surface of the ribs in heat transfer causes differences in the obtained results of the Nusselt number depending on the method used. Apart from the heat transfer data, the pressure drop in the form of friction factors is also presented. On the basis of the conducted research, it can be stated that both qualitative and quantitative coherence was obtained between the experimental and computational studies.

  • Modeling protein structures with the coarse-grained UNRES force field in the CASP14 experiment
    • Anna Antoniak
    • Iga Biskupek
    • Krzysztof K. Bojarski
    • Cezary Czaplewski
    • Artur Giełdoń
    • Mateusz Kogut
    • Małgorzata M. Kogut
    • Paweł Krupa
    • Agnieszka Lipska
    • Adam Liwo
    • Emilia Lubecka
    • Mateusz Marcisz
    • Martyna Maszota-Zieleniak
    • Sergey A. Samsonov
    • Adam K. Sieradzan
    • Magdalena J. Ślusarz
    • Rafał Ślusarz
    • Patryk A. Wesołowski
    • Karolina Ziȩba
    2021 Full text JOURNAL OF MOLECULAR GRAPHICS & MODELLING

    The UNited RESidue (UNRES) force field was tested in the 14th Community Wide Experiment on the Critical Assessment of Techniques for Protein Structure Prediction (CASP14), in which larger oligomeric and multimeric targets were present compared to previous editions. Three prediction modes were tested (i) ab initio (the UNRES group), (ii) contact-assisted (the UNRES- contact group), and (iii) template-assisted (the UNRES-template group). For most of the targets, the contact restraints were derived from the server models top-ranked by the DeepQA method, while the DNCON2 method was used for 11 targets. Our consensus- fragment procedure was used to run template-assisted predictions. Each group also processed the Nuclear Magnetic Resonance (NMR)- and Small Angle X-Ray Scattering (SAXS)-data assisted targets. The average Global Distance Test Total Score (GDT TS) of the ‘Model 1’ predictions were 29.17, 39.32, and 56.37 for the UNRES, UNRES-contact, and UNRES-template predictions, respectively, increasing by 0.53, 2.24, and 3.76, respectively, compared to CASP13. It was also found that the GDT TS of the UNRES models obtained in ab initio mode and in the contact-assisted mode decreases with the square root of chain length, while the exponent in this relationship is 0.20 for the UNRES-template group models and 0.11 for the best performing AlphaFold2 models, which suggests that incorporation of database information, which stems from protein evolution, brings in long-range correlations, thus enabling the correction of force-field inaccuracies.

  • Modeling SARS‐CoV‐2 proteins in the CASP‐commons experiment
    • Andriy Kryshtafovych
    • John Moult
    • Wendy M. Billings
    • Dennis Della Corte
    • Krzysztof Fidelis
    • Sohee Kwon
    • Kliment Olechnovič
    • Chaok Seok
    • Česlovas Venclovas
    • Jonghun Won
    • Alphafold Team
    • Badri Adhikari
    • Recep Adiyaman
    • Joaquim Aguirre-plans
    • Ivan Anishchenko
    • Minkyung Baek
    • David Baker
    • Frederico Baldassarre
    • Jacob Barger
    • Sutanu Bhattacharya
    • Debswapna Bhattacharya
    • Mor Bitton
    • Renzhi Cao
    • Jianlin Cheng
    • Charles Christoffer
    • Cezary Czaplewski
    • Zongyang Du
    • Arne Elofsson
    • Eshel Faraggi
    • Michael Feig
    • Narcis Fernandez-fuentes
    • Nick Grishin
    • Sergei Grudinin
    • Zhiye Guo
    • Yuya Hanazono
    • Demis Hassabis
    • Bryce Hedelius
    • Lim Heo
    • Naozumi Hiranuma
    • Cassandra Hunt
    • Ilia Igashov
    • Takashi Ishida
    • Robert L. Jernigan
    • David Jones
    • John Jumper
    • Maria Kadukova
    • Shaun Kandathil
    • Chen Keasar
    • Daisuke Kihara
    • Lisa Kinch
    • Yasuomi Kiyota
    • Andrzej Kloczkowski
    • Pushmeet Kohli
    • Mateusz Kogut
    • Elodie Laine
    • Cade Lilley
    • Jian Liu
    • Adam Liwo
    • Emilia Lubecka
    • Arup Mondal
    • Connor J. Morris
    • Liam Mcguffin
    • Alexis Molina
    • Tsukasa Nakamura
    • Baldo Oliva
    • Alberto Perez
    • Gabriele Pozzati
    • Daipayan Sarkar
    • Rin Sato
    • Torsten Schwede
    • Bikash Shrestha
    • Tomer Sidi
    • Gabriel Studer
    • Md Hossain Shuvo
    • Mayuko Takeda-shitaka
    • Yuma Takei
    • Genki Terashi
    • Kentaro Tomii
    • Yuko Tsuchiya
    • Kathryn Tunyasuvunakool
    • Bjorn Wallner
    • Tianqi Wu
    • Jinbo Xu
    • Yu Yamamori
    • Jianyi Yang
    • Lisha Ye
    • Chengxin Zhang
    • Yang Zhang
    • Wei Zheng
    2021 PROTEINS-STRUCTURE FUNCTION AND BIOINFORMATICS

    Critical Assessment of Structure Prediction (CASP) is an organization aimed at advancing the state of the art in computing protein structure from sequence. In the spring of 2020, CASP launched a community project to compute the structures of the most structurally challenging proteins coded for in the SARS-CoV-2 genome. Forty-seven research groups submitted over 3000 three-dimensional models and 700 sets of accuracy estimates on 10 proteins. The resulting models were released to the public. CASP community members also worked together to provide estimates of local and global accuracy and identify structure-based domain boundaries for some proteins. Subsequently, two of these structures (ORF3a and ORF8) have been solved experimentally, allowing assessment of both model quality and the accuracy estimates. Models from the AlphaFold2 group were found to have good agreement with the experimental structures, with main chain GDT_TS accuracy scores ranging from 63 (a correct topology) to 87 (competitive with experiment).

  • Modelling AOB-NOB competition in shortcut nitrification compared with conventional nitrification-denitrification process
    • Jakub Drewnowski
    • Mehdi Sharifshourjeh
    • Przemysław Kowal
    • W Cel
    2021 Full text Journal of Physics : Conference Series

    In particular, mainstream deammonification and/or shortened nitrificationdenitrification via nitrite (so-called “nitrite shunt”) is a promising new treatment concept that has the potential to revolutionise how nitrogen removal is achieved at WWTPs. Understanding the role of the AOB/NOB competition in the nitrogen cycle in wastewater treatment systems will change operational strategies of the novel nitrogen removal processes. The key role in this process is inhibition of NOB activity undesirably affects AOB activity and leads to inefficient partial nitrification process and when used as pre-treatment for Anammox it can limit nitrite supply to Anammox bacteria. Successful NOB repression requires a combination of such factors as a low DO concentration, a rapid transition from aerobic to anoxic conditions, and tight control of Temperature and/or pH. The major driving force behind the successful NOB washout is the inhibition of those bacteria based on the difference in the growth rate between AOB and NOB. The obtained results from this study show the mechanisms and operating conditions (e.g. DO concentration, Temp.) leading to complete domination of AOB over NOB under aerobic conditions. This paper presents the perspectives on modelling AOB-NOB competition in shortcut nitrification. The combined deammonification, shortened nitrification-denitrification and/or nitritation-anammox process was compared with conventional nitrification-denitrification based on own experiments and literature data. Its successful application as shortcut nitrification technology and new control system will represent a paradigm shift for the wastewater industry, offering the opportunity for sustainable wastewater treatment, energy-neutral or even energypositive facilities, and substantial reductions in treatment costs.

  • Modelling Long‐Term Transition from Coal‐Reliant to Low‐Emission Power Grid and District Heating Systems in Poland
    • Marcin Jaskólski
    • Paweł Bućko
    2021 Full text ENERGIES

    Energy systems require technological changes towards climate neutrality. In Poland, where the power system is dominated by outdated coal-fired power plants, efforts to minimize the environmental impact are associated with high costs. Therefore, optimal paths for the development of the energy sector should be sought in order to achieve ambitious long-term strategic goals, while minimizing the negative impact on the consumers’ home budget. A methodology and a model for the development of the electricity and heat generation structure were developed and implemented in market allocation (MARKAL) modelling framework. Two scenarios were presented, i.e., business as usual (BAU) and withdrawal from coal (WFC) scenarios. The calculations showed a significant role of nuclear energy and offshore wind power in the pursuit of climate neutrality of electricity generation. In the BAU scenario, the model proposes to stay with coal technologies using carbon capture and storage systems. Withdrawal from coal (WFC scenario) makes it necessary to replace them by gas-fired power plants with CO2 sequestration. Solar energy can be used both in electricity and district heating. In order to build on the latter technological option, appropriate energy storage techniques must be developed. Geothermal energy is expected to be the key option for district heat generation in the long-term horizon. The proposed development paths guarantee a significant reduction in greenhouse gases and industrial emissions. However, complete climate neutrality is uncertain, given the current degree and dynamics of technological development.

  • Modelling of dark fermentation of glucose and sour cabbage
    • Gaweł Sołowski
    • Krzysztof Pastuszak
    2021 Full text Heliyon

    In the article, modified Anaerobic Digestion Models 1 (ADM-1) was tested for modelling dark fermentation for hydrogen production. The model refitting was done with the Euler method. The new model was based on sets of differential equations. The model was checked for hydrogen production from sour cabbage in batch and semi-batch in 5 g VSS (volatile solid suspension)/L and at the semi-batch process from glucose at 5 and 10 g VSS/L. Added parameters determined the conversion of a substrate, hydrogen production, and stress parameters. In the case of a semi-batch process, for one month, cumulative hydrogen production from sour cabbage of 5 g VSS/L was 0.9 L of cumulative hydrogen volume and from glucose 5 g VSS/L (in case of feeding 2 g VSS/L every two days) 2.5 L of cumulative hydrogen volume. At the bacterial population level, hydrogen production was a continuous process at an adequate range of population size and environmental parameters

  • Modelling of full-scale silo experiments with flow correcting inserts using material point method (MPM) based on hypoplasticity.
    • Jakub Krzyżanowski
    • Andrzej Tejchman-Konarzewski
    • Michał Wójcik
    2021 POWDER TECHNOLOGY

    Charakterystyki przepływu materiałów sypkich w silosach mają znaczenie dla naporów wywieranych na ściany silosu. Można je zmieniać za pomocą różnych wkładek. W pracy omówiono wyniki liczbowe dotyczące ograniczonego przepływu niespoistego ziarnistego piasku w pełnowymiarowym silosie metalowym z różnymi symetrycznie rozmieszczonymi wkładami, służącymi do korekcji wzorca przepływu (podwójny stożek, stożek w stożku i odwrócony stożek). Do symulacji dynamicznego przepływu piasku w silosie zastosowano metodę punktu materialnego (MPM). Do opisu zachowania płynięcia piasku niespoistego przyjęto hipoplastyczny model konstytutywny. Nacisk położono na schematy przepływu i napory na ściany i wkładki silosu. Wyniki liczbowe zostały bezpośrednio porównane z odpowiednimi eksperymentami w silosie pełnowymiarowym. Osiągnięto zadowalającą zgodność wyników liczbowych i eksperymentalnych. W obliczeniach MPM zbadano również wpływ początkowego współczynnika porowatości piasku, kąta tarcia ściany silosu, położenia wkładki silosowej i rozmiaru komórek siatki MPM.

  • Modelling of shear zones during quasi-static granular silo flow using material point method (MPM)
    • Jakub Krzyżanowski
    • Andrzej Tejchman-Konarzewski
    • Wojciech Sołowski
    • Michał Wójcik
    2021 Full text POWDER TECHNOLOGY

    The paper focuses on confined silo flow of cohesionless sand. The problem considered is a quasi-static flow in a plane strain model silo with parallel walls simulated with the material point method (MPM). The simulation used a non-local hypoplastic constitutive model. Initially, the paper validated the implemented numerical approach with basic element tests and a plane strain compression test. The subsequent MPM calculations for a model silo were performed with different initial void ratios of sand and silo wall roughness. The flow simulations took also into account the different both location and width of the outlet. The emphasis was on the evolution of both shear zones (wall and internal curvilinear shear zones) and their impact on wall stresses/forces during flow. The numerical findings enhance the understanding of shear localization in granular materials during confined controlled flow in silos and its immense effect on the magnitude and distribution of wall pressures.

  • MODERNIZACJA DYDAKTYCZNEGO STANOWISKA LABORATORYJNEGO UMOŻLIWIAJĄCEGO ANALIZĘ PORÓWNAWCZĄ SPRAWNOŚCI ŚRUB NAPĘDOWYCH JACHTU MOTOROWEGO
    • Piotr Bzura
    2021 Full text Journal of Polish CIMEEAC

    W artykule przedstawiono autorską metodę wyznaczania sprawności działania różnych śrub napędowych jachtu motorowego na podstawie wyników badań wykonanych na zmodernizowanym stanowisku laboratoryjnym. Modernizacja stanowiska składającego się ze źródła mocy w postaci silnika elektrycznego, części pośredniczącej i pędnika polegała na dodaniu przetwornika częstotliwości umożliwiającego starowanie silnikiem elektrycznym, czujnika do pomiaru prędkości wody względem pędnika i zanurzenia pędnika (śruby napędowej) w kanale przepływowym. Na podstawie analizy przeprowadzonych badań został przedstawiony algorytm, według którego porównano dwie różne śruby napędowe.

  • Modification of cellulosic filler with diisocyanates – volatile organic compounds emission assessment and stability of chemical structure over time
    • Aleksander Hejna
    • Mariusz Marć
    • Jerzy Korol
    2021 Full text NORDIC PULP & PAPER RESEARCH JOURNAL

    This paper investigated the impact of type and content of diisocyanate on the structure of modified cellulose fillers. Four the most popular isocyanates were applied – isophorone, hexamethylene, toluene and methylene diphenyl diisocyanate – at loadings of 1–15 wt%. Chemical structure, and its short-term storage stability, were investigated for eight weeks. Moreover, the main volatile organic compounds detected during modification, as well as emitted from fillers before and after storage, were identified. The main compounds detected in the air during modifications were terpenes and terpenoids. No diisocyanates were detected, which is very beneficial considering their toxicity. They were emitted from modified fillers at 40 °C, but only from fresh samples. After storage no emissions were noted, which indicated successful modification of fillers, also confirmed by FTIR spectroscopy and changes in polarity of fillers’ surface. Observed changes should be considered beneficial for the potential applications of modified fillers in manufacturing of polymer composites.

  • Modification of structured bio‑carbon derived from spongin-based scaffolds with nickel compounds to produce a functional catalyst for reduction and oxidation reactions: Potential for use in environmental protection
    • Sonia Żółtowska
    • Zuzanna Bielan
    • Joanna Zembrzuska
    • Katarzyna Siwińska-Ciesielczyk
    • Adam Piasecki
    • Anna Zielińska-Jurek
    • Teofil Jesionowski
    2021 Full text SCIENCE OF THE TOTAL ENVIRONMENT

    Three different 3D fibrous-like NiO/Ni(OH)2/Ni‑carbonized spongin-based materials were prepared via a simple sorption–reduction method. Depending on the support used, the catalysts were composed of carbon, nickel oxide, nickel hydroxide and zero-valent nickel, with the surface content of the nickel-containing phase in the range 15.2–26.0 wt%. Catalytic studies showed promising activity in the oxidation of phenolic compounds in water and in the reduction of 4-nitrophenol. The oxidation efficiency depends on the substrate used and ranges from 80% for phenol at pH 2 to 99% for 4-chlorophenoxyacetic acid (4-CPA) and methylchlorophenoxypropionic acid (MCPP). In the reduction reaction, all catalysts exhibited superior activity, with rate constants in the range 0.648–1.022 min-1. The work also includes a detailed investigation of reusability and kinetic studies.

  • Modified Inductive Multi-Coil Wireless Power Transfer Approach Based On Z-Source Network
    • Bohdan Pakhaliuk
    • Oleksandr Husev
    • Viktor Shevchenko
    • Janis Zakis
    • Maksym Khomenko
    • Ryszard Strzelecki
    2021 Full text IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS

    This article presents a non-conventional approach to a multi-coil wireless power transfer system based on a Z-source network. The novelty of the approach lies in the use of a Z-source as a voltage source for energy transmission through the wireless power transfer coils. The main advantage is in a reduced number of semiconductors. This paper provides the design approach, simulation and experimental study. Feasibility and possible application fields are presented in the conclusions.

  • Modified SPWM Technique with Zero-Sequence Voltage Injection for a Five-Phase, Three-Level NPC Inverter
    • Charles Odeh
    • Dmytro Kondratenko
    • Arkadiusz Lewicki
    • Andrzej Jąderko
    2021 Full text ENERGIES

    This article presents a modified sinusoidal pulse-width modulation (SPWM) scheme for a five-phase, three-level neutral-point-clamped inverter. The modulation scheme deploys a modified min–max function to inject the zero-sequence components into the reference modulating signals; hence enabling the effective utilization of the DC-link voltage. Balanced split-input DC-link voltages were achieved through further incorporation of adjustable voltage-dependent variables into the reference signals. The dynamic performance of the control approach is demonstrated through simulations and experiments on a laboratory inverter prototype; the results are well presented.

  • Modular Approach for Modelling Warming Up Process in Water Installations with Flow-Regulating Elements
    • Jacek Kropiwnicki
    • Mariusz Furmanek
    • Andrzej Rogala
    2021 Full text ENERGIES

    The paper presents a new method for modelling the warming up process of a water system with elements regulating the flow in a stochastic manner. The paper presents the basic equations describing the work of typical elements which the water installation is composed of. In the proposed method, a new computational algorithm was used in the form of an iterative procedure enabling the use of boundary conditions that can be stochastically modified during the warming-up process. A typical situation, when such a modification is processed, is the regulation of the medium flow through two-way or three-way valves or applying additional heat source. Moreover, the presented method does not require the transformation of the differential equations, describing the operation of individual elements, into a linear form, which significantly facilitates analytical work and makes it more flexible. The example of analysis of the operation of water installation used for controlling temperature of the process gases in a chemical installation shows the functionality and flexibility of the method. The adopted calculation schematics enable changing the direction of the heat flow while the heat exchanger is in operation. Additionally, the sequence of calculation processed in modules describing operation of installation elements is elective (there is no situation that output parameters from one element are used as input parameters for other element in the same calculation step).