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Gdańsk University of Technology

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  • Sustainable upcycling of brewers’ spent grain by thermo-mechanical treatment in twin-screw extruder
    • Aleksander Hejna
    • Mateusz Barczewski
    • Katarzyna Skórczewska
    • Joanna Szulc
    • Błażej Chmielnicki
    • Jerzy Korol
    • Krzysztof Formela
    2021 Full text JOURNAL OF CLEANER PRODUCTION

    Thermo-mechanical treatment of brewers’ spent grain (a by-product of beer manufacturing) was successfully performed via the extrusion process. The impact of temperature (from 30 to 180 °C), throughput (from 1 to 5 kg/h) and screw speed (from 75 to 375 rpm) on particle size, color, chemical structure, antioxidant activity and thermal stability of resulting material, as well as correlations between particular properties, were investigated. The color of treated brewers’ spent grain was strongly influenced by particle size and the extent of Maillard reactions occurring during extrusion, responsible for the browning of material. Moreover, products of these reactions, melanoidins, enhanced the antioxidant activity of brewers’ spent grain, which after extrusion at 180 °C was increased by even 100%. Thermo-mechanical treatment of brewers’ spent grain at 120 and 180 °C increased its thermal stability investigated by thermogravimetric analysis. It was also observed that temperature treatment above 100 °C also led to the reduction in friction inside the extruder barrel and reduced by at least 20% specific mechanical energy required to brewers’ spent grain modification, which positively affects the economic aspect of the process. The results confirm that a proper adjustment of extrusion parameters allows easy tailoring of the appearance (color, particle size distribution) and performance properties (thermal stability, antioxidant activity) of brewers’ spent grain, which significantly extend applications of this cellulosic-rich waste in wood polymer composites technology.

  • Sustainable Use of the Catenary by Trolleybuses with Auxiliary Power Sources on the Example of Gdynia
    • Mikołaj Bartłomiejczyk
    • Marcin Połom
    2021 Full text Infrastructures

    The current developments in onboard power source technology, in particular, traction batteries, open up new potential in trolleybus transport and also make it possible to introduce electric buses. Thus far, trolleybus transport has required the presence of overhead lines (OHL). Introducing trolleybuses with onboard batteries makes it possible to grow the zero-emissions transport network in places with limited power supply capabilities and low population density, or in places where building OHL would not be possible. This improves the efficiency of trolleybus transport and makes environmentally friendly public transport more accessible to the local citizens. Despite their obvious advantages, traction batteries can also be problematic, as the drivers may overuse them (e.g., in the event of pantograph failure), and the public transport authorities and transport companies may plan connections in an ineffective way without preparing the necessary infrastructure (the absence of slipways or automatic connection capabilities), which in turn leads to inefficient use of the OHL. The article outlines the operation of the trolleybus transport network in Gdynia. The use of traction batteries in regular connections is analysed, and the potential for electrification of the bus line, some sections of which follow the traction infrastructure, is examined.

  • Synagogi dawnej Polski - ich teraźniejszość i przyszłość
    • Joanna Kabrońska
    2021

    Tekst stanowi próbę ujęcia w szerszej perspektywie złożonego zjawiska zmiany formy użytkowania ocalałych obiektów kultu religijnego. Postępująca sekularyzacja współczesnych społeczeństw stanowi wyzwanie dla religijnych społeczności różnych wyznań, przynosząc również pytania dotyczące zmiany przeznaczenia pustoszejących świątyń. Biorąc pod uwagę społeczny kontekst zarysowany powyżej, ocalałe budynki synagog można uznać za odrębny, trudny problem. Dawne społeczności żydowskie, będące gospodarzami obiektów, stały się ofiarami wojny, a nieliczni, którzy przetrwali wojnę, wyjechali z Polski w kolejnych falach emigracji. Pozostały bóżnice i cmentarze, którymi nie ma się kto opiekować, ponieważ nie istnieje już wspólnota religijna. Wskazanie formy użytkowania budynków, które pierwotnie były domami modlitwy i miejscami zebrań gminy żydowskiej, nie byłoby właściwe bez dopuszczenia do głosu współczesnej społeczności żydowskiej. Jednak różnorodność poglądów i interpretacji, związana z tym problemem, czyni zadanie jeszcze trudniejszym. Rozpatrując zjawisko zmiany formy użytkowania ocalałych synagog, warto również zwrócić uwagę na rolę artystów, którzy uczynili architekturę ocalałych obiektów kultu religijnego tworzywem swoich działań artystycznych. Często jako pierwsi ujawniają oni wrośnięte w krajobraz budynki i przywołują ich pierwotne przeznaczenie, czyniąc sztukę w pewnym sensie narzędziem resakralizacji tych obiektów i jednocześnie ukazując nowe kierunki myślenia o ich przyszłości.

  • Synergistic Effects of Propolis Combined with 2-Phenoxyethanol and Antipyretics on the Growth of Staphylococcus aureus
    • Katarzyna Grecka
    • Piotr Szweda
    2021 Full text Pharmaceutics

    The present investigation aimed to assess the combinational effect of commonly usedantipyretics and antiseptics with ethanolic extracts of propolis (EEPs) on the growth inhibition ofStaphylococcus aureus. The broth microdilution checkerboard assay revealed synergistic interactionsbetween all investigated antipyretics, namely acetylsalicylic acid, ibuprofen, and acetaminophen,with EEPs samples. The values of the fractional inhibitory concentration (ΣFIC) index for all thesecombinations were <0.5. While, in the case of considered antiseptics, namely chlorhexidine, octenidinedihydrochloride, and 2-phenoxyethanol, the positive interaction was confirmed only for the last one(values ofΣFIC in the range 0.0625–0.25). Combinations of two other agents with all four samples ofEEPs resulted in an important antagonistic effect (values ofΣFIC≥4.5). Propolis is mostly dedicatedto the treatment of skin/wound infections; thus, these findings are of particular practical importance.The outcomes of the study also support the hypothesis that the propolis’s antimicrobial effect is dueto the combined (synergistic) action of several ingredients rather than the presence of one componentof high antibacterial activity. The composition of 13 ingredients of EEPs (at a concentration belowthe MIC (minimum inhibitory concentration) of the most active agent) exhibited considerably highanti-staphylococcal efficiency with MIC = 128μg/mL.

  • Synteza, struktura chemiczna i właściwości bezizocyjanianowych poliuretanów otrzymywanych z wykorzystaniem CO2 oraz surowców pochodzenia naturalnego.
    • Kamila Rohde
    2021

    Z uwagi na wciąż rosnącą świadomość proekologiczną, politykę zrównoważonego rozwoju, a także nurt zielonej chemii wiodącym trendem w przemyśle tworzyw sztucznych jest poszukiwanie alternatywnych metod otrzymywania materiałów polimerowych. Komercyjnie poliuretany otrzymywane są w wyniku reakcji poliaddycji di- lub poliizocyjanianów z poliolami i małocząsteczkowymi przedłużaczami łańcucha. Z uwagi na niekorzystne właściwości diizocyjanianów, a także prognozowane zmniejszenie zasobów ropy naftowej i związany z tym wzrost cen rynkowych surowców, ośrodki naukowo-badawcze poszukują nowych metod syntezy tych materiałów. Głównym celem prezentowanej rozprawy doktorskiej było otrzymanie bezizocyjanianowych poliuretanów w wyniku reakcji poliaddycji cyklicznych węglanów oraz di- lub poliamin z zastosowaniem monomerów pochodzenia roślinnego i dwutlenku węgla, jako reagenta wbudowywanego w strukturę eterów diglicydylowych. Cel realizowano poprzez wykorzystanie komercyjnie dostępnego poli(glikolu trimetylenowego) pochodzenia roślinnego oraz aminowych pochodnych zdimeryzowanych kawasów tłuszczowych. Ponadto, dwutlenek węgla w reakcji cykloaddycji wbudowywano w strukturę półproduktów zakończonych grupami oksiranowymi. Opracowana metoda nie wymaga zastosowania podwyższonego ciśnienia, możliwe jest kontrolowanie prędkości przepływu gazu, a także nie ma konieczności stosowania toksycznych rozpuszczalników organicznych. Niniejsza rozprawa doktorska oparta jest na czterech artykułach opublikowanych w recenzowanych czasopismach naukowych. W ramach prowadzonych prac badawczych szczegółowo scharakteryzowano strukturę chemiczną, a także wybrane właściwości otrzymywanych na każdym etapie prac produktów.

  • Synthesis and Characterization of Poly(zwitterionic) Structures for Energy Conversion and Storage
    • Adrian Olejnik
    • Siuzdak Katarzyna
    • Katarzyna Grochowska
    2021

    Zwitterions are unique class of molecules that possess two functional groups bearing electric charges, one positive and second negative. This setup results in peculiar properties such as high water retention and anti-fouling capability. Therefore, zwitterionic coatings and gels are commonly applied in e.g. biosensing and bioelectronic devices. Despite those applications, there are other perspectives for zwitterionic materials. Recently, they have gained attention in the fields of energy storage and conversion. In particular, gel electrolytes for batteries and solid state supercapacitors based on zwitterionic polymers have significantly higher ionic conductivity compared to standard electrolytes based on e.g. poly(vinyl alcohol). Moreover,the capacitance of devices with zwitterionic electrolytes is generally few times higher and retained after a larger number of cycles. Zwitterions are also prominent interlayers between photoactive materials and electrical contacts in organic and perovskite solar cells facilitating charge injection. Considering the unique properties of zwitterions and a large variety of available structures, they have become animportant point of scientific attention in the field of energy storage and conversion. Despite some concepts have already been developed, there is plenty to be discovered about these materials. In our opinion zwitterions can be regarded as the most prospective ones in energy fields.

  • Synthesis and Physicochemical Characteristics of Chitosan-Based Polyurethane Flexible Foams
    • Agnieszka Piotrowska-Kirschling
    • Adam Olszewski
    • Jakub Karczewski
    • Łukasz Piszczyk
    • Joanna Brzeska
    2021 Full text Processes

    The use of shrimp waste to obtain chitosan (Ch) is an essential issue, considering a circular economy, waste management, and its application to environmentally friendly materials. In this study, northern prawn shells were utilized to obtain Ch, which could then be used for synthesizing chitosan-based polyurethane (PUR+Ch) foams with different Ch concentration. The chemical structure, morphology, hardness, thermal properties, viscoelastic properties, and sorption properties in relation to oil and water of these materials were determined. The results present that the addition of Ch into PUR influences the physicochemical characteristics and properties of the tested materials. PUR+Ch foams with 1–3 wt% Ch had more open cells and were softer than neat PUR. PUR+Ch1 had the best thermal properties. PUR+Ch2 foam with 2 wt% Ch as a whole was characterized as having the highest water sorption. The PUR+Ch1 foam with 1 wt% Ch had the best oil sorption. This paper shows that the modification of PUR by Ch is a very promising solution, and PUR+Ch foams can be applied in the water treatment of oil spills, which can be dangerous to the water environment.

  • Synthesis and structural characterization of bio-based bis(cyclic carbonate)s for the preparation of non-isocyanate polyurethanes
    • Kamila Błażek
    • Hynek Beneš
    • Zuzana Walterová
    • Sabina Abbrent
    • Arantxa Eceiza
    • Tamara Calvo-Correas
    • Janusz Datta
    2021 Polymer Chemistry

    Bio-based cyclic carbonates are of significant research interest as monomers for non-isocyanate polyurethane (NIPU) synthesis. This research describes the synthesis of a series of five-membered bis(cyclic carbonate)s using bio-based polyether polyols (PO3G) with different molecular weights (250, 650 and 1000 g mol−1) and carbon dioxide as green feedstocks. The utilization of CO2 as a source of carbon in the chemical reaction is in agreement with the sustainable chemical industry. Furthermore, in order to support the green and sustainable polymer chemistry approach, the syntheses were attempted under solvent-free conditions. The implemented synthetic methods are focused on the design of processes and final products that minimize negative environmental impact. Detailed chemical structure analysis of synthesized products was performed using a combination of spectroscopy techniques (ATR-FTIR as well as 1D and 2D NMR techniques), mass spectrometry (MALDI-TOF MS) and chromatography analysis (SEC). The formation of the main product with two terminal cyclic carbonates was confirmed and the formed side products were also identified, characterized and quantified. Finally, as a proof of concept, the synthesized bis(cyclic carbonate)s were successfully used for the preparation of NIPU thermosets. Chemical and mechanical properties of the produced materials suggest their high potential for future applications, e.g. as sound absorbing materials.

  • Synthesis and Structure of Novel Copper(II) Complexes with N,O- or N,N-Donors as Radical Scavengers and a Functional Model of the Active Sites in Metalloenzymes
    • Joanna Masternak
    • Małgorzata Zienkiewicz-Machnik
    • Iwona Łakomska
    • Maciej Hodorowicz
    • Katarzyna Kazimierczuk
    • Milena Nosek
    • Amelia Majkowska-Młynarczyk
    • Joanna Wietrzyk
    • Barbara Barszcz
    2021 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Toevaluatetheantioxidantactivityofpotentialsyntheticenzymemimetics,wepreparednewfivecopper(II)complexesviaaself‐assemblymethodandnamedthem[Cu(2‐(HOCH2)py)3](ClO4)2(1),[Cu(2‐(HOCH2)py)2(H2O)2]SiF6(2),[Cu2(2‐(HOCH2CH2)py)2(2‐(OCH2CH2)py)2](ClO4)2(3),[Cu(pyBIm)3](BF4)2∙1.5H2O(4)and[Cu(py2C(OH)2)2](ClO4)2(5).ThesyntheticprotocolinvolvedN,O‐ orN,N‐donors:2‐(hydroxymethyl)pyridine(2‐(HOCH2)py),2‐(hydroxyethyl)pyridine(2‐(HOCH2CH2)py),2‐(2‐pyridyl)benzimidazole(pyBIm),di(2‐pyridyl)ke‐tone(py2CO).TheobtainedCu(II)complexeswerefullycharacterisedbyelementalanalysis,FTIR,EPR,UV‐Vis,single‐crystalX‐raydiffractionandHirshfeldsurfaceanalysis.Crystallographicandspectroscopicanalysesconfirmedchromophoresofbothmonomeric({CuN3O3}(1),{CuN2O4}(2),{CuN6}(4),{CuN4O2}(5))anddimericcomplex({CuN2O3}(3)).Mostoftheobtainedspeciespos‐sessedadistortedoctahedralenvironment,exceptdimer3,whichconsistedoftwocoppercentreswithsquarepyramidalgeometries.Thewater‐solublecompounds(1,3and5)wereselectedforbiologicaltesting.Theresultsofthestudyrevealedthatcomplex1insolutionsdisplayedbetterradicalscavengingactivitythancomplexes3,5andfreeligands.Therefore,complex1hasbeenselectedforfurtherstudiestotestitsactivityasanenzymemimetic.Thechosencompoundwastestedontheerythrocytelysateoftwogroupsofpatientsafterundergoingchemotherapyandchemoradiotherapy.Theeffectofthetestedcompound(1)onenzymeactivitylevels(TAS,SODandCAT)suggeststhattheselectedcomplexcanbetreatedasafunctionalmimeticoftheenzymes.

  • Synthesis, characteristics, and photocatalytic activity of zinc oxide nanoparticles stabilized on the stone surface for degradation of metronidazole from aqueous solution
    • Amir Naser Alibeigi
    • Neda Javid
    • Majid Amiri Gharaghani
    • Zhila Honarmandrad
    • Fatemeh Parsaie
    2021 Full text Environmental Health Engineering and Management Journal

    Abstract Background: The presence of antibiotics such as metronidazole in wastewater even at low concentrations requires searching for a suitable process such as advanced oxidation process (AOP) to reduce the level of pollutants to a standard level in water. Methods: In this study, zinc oxide (ZnO) nanoparticles were synthesized by thermal method using zinc sulfate (ZnSO4) as a precursor, then, stabilized on stone and was used as a catalyst, in order to degrade metronidazole by photocalytic process. Effective factors on the removal efficiency of metronidazole including the initial metronidazole concentration, contact time, pH, and 0.9 gL-1 ZnO stabilized on the stone surface were investigated. Results: The X-ray diffraction (XRD) studies showed that the synthesized nanomaterials have hexagonal Wurtzite structure. Also, scanning electron microscopy (SEM) analysis revealed that the average crystalline size of the synthesized ZnO particles was in the range of 1.9-3.2 nm. The spectra represented a sharp absorption edge at 390 nm for ZnO nanoparticles corresponding to band gap of 3.168 eV. The BET-BJH specific surface area of the synthesized ZnO nanoparticles was 25.504 m2/g. The EDS spectrum of ZnO nanoparticles showed four peaks, which were identified as Zn and O. The maximum removal efficiency was 98.36% for the synthetic solution under a specific condition (pH = 11, reaction time = 90 minutes, ZnO concentration = 0.9 gL-1, and the initial concentration of metronidazole = 10 mgL-1). The photocatalytic degradation was found to follow pseudo-first-order degradation kinetics. Conclusion: Therefore, the ZnO nanoparticles synthesized by thermal decomposition are suitable and effective photocatalytic materials for degradation of pharmaceutical contaminants.

  • Synthesis of Phosphonated Carbon Nanotubes: New Insight into Carbon Nanotubes Functionalization
    • Małgorzata Nadolska
    • Marta Prześniak-Welenc
    • Marcin Łapiński
    • Kamila Sadowska
    2021 Full text Materials

    Carbon nanotubes were successfully functionalized for the first time in a free radical phosphonylation reaction. Three synthetic protocols were proposed. Carbon nanotubes and diethylphosphite reacted in the presence of known radical initiator, such as azobisisobutyronitrile, single electron oxidant—Mn(OAc)3, or under UV radiation. The functionalized material was fully characterized by means of spectroscopic methods, together with microscopic, surface area and thermogravimetric analyses. UV-illumination was found to be the most effective approach for introducing phosphonates onto carbon nanotubes. X-ray photoelectron spectroscopy analysis showed 6% phosphorus in this sample. Moreover, the method was performed at room temperature for only one hour, using diethylphosphite as a reactant and as a solvent. The functionalized carbon nanotubes showed an improved thermal stability, with a decomposition onset temperature increase of more than 130 °C. This makes it very promising material for flame retarding applications.

  • SYNTHETIZED MEMBRANES FOR ULTRASOUND-ASSISTED SOLVENT EXTRACTION OF POROUS MEMBRANE PACKED SOLID SAMPLES.
    • Martyna Jurczyk
    • Justyna Płotka-Wasylka
    • Emilia Gontarek-Castro
    2021 Full text

    Membranes are becoming more and more popular in analytical chemistry, which is why they are used, among others, in extraction processes. Therefore, this work focuses on the process of synthesis PVDF membranes and its optimization. The obtained membranes were used as bags for the phthalate extraction in disposable diapers for babies. Extraction was accomplished by method ultrasound-assisted solvent extraction of porous PVDF membrane packed solid samples. As a result of the research, it was found that the most optimal temperature for the synthesis of membranes was 40°C. The phthalates were extracted in this process. However, the reproducibility was insufficient.

  • System do diagnostyki dermatofitowych zakażeń powierzchniowych oparty na technice Real-Time PCR
    • Natalia Kobylak
    2021 Full text

    Dermatofity należą do blisko spokrewnionej grupy grzybów, które wykazują wysokie powinowactwo do skeratynizowanych tkanek. Cecha ta czyni je odpowiedzialnymi za powierzchniowe grzybice skóry, paznokci oraz włosów. Szacuje się, iż nawet do 20% ludzi na całym świecie dotkniętych jest infekcjami powodowanymi przez dermatofity. Ich leczenie wymaga długotrwałego zastosowania leków przeciwgrzybiczych. W celu dobrania odpowiedniego leczenia należy zapewnić prawidłową diagnozę, która przy zastosowaniu konwencjonalnych metod jest nie tylko długotrwała, ale również kosztowna, jak i wymaga wieloletniego doświadczenia diagnosty. Biorąc powyższe pod uwagę, niezmiernie istotne jest stworzenie szybkiego i prostego testu diagnostycznego, opartego na metodach molekularnych, który zapewni identyfikację gatunkową. Celem badań prowadzonych w ramach niniejszej pracy doktorskiej było opracowanie testu diagnostycznego, który w pierwszym etapie wykrywałby dermatofity, a w drugim etapie zapewniłby identyfikację gatunkową oraz co wydawało się największym wyzwaniem opracowanie jednoetapowej metody przygotowania DNA, które mogłoby być stosowane w technice Real-Time PCR. W pierwszym etapie pracy wykazano możliwość zastosowanie DNA wyizolowanego szybką, dwuetapową w reakcjach Real-Time PCR przy użyciu starterów wykrywających DNA wszystkich dermatofitów oraz starterów wykrywających DNA gatunku Trichophyton rubrum. Następnie, zostały zaprojektowane startery umożliwiające wykrycie DNA gatunków Epidermophyton floccosum, Microsporum canis, Microsporum audouinii/Microsporum ferrugineum oraz kompleksu Trichophyton mentagrophytes. Zaprojektowane układy przetestowano na 246 izolatach oraz wstępnie potwierdzono możliwość ich zastosowania z użyciem próbek klinicznych. Na sam koniec opracowano nową metodę szybszej izolacji DNA dermatofitów, charakteryzującą się mniejszym ryzykiem kontaminacji w porównaniu z istniejącymi metodami.

  • Systematic Assessment of Product Quality
    • Radosław Drozd
    • Radosław Wolniak
    2021 Full text Journal of Open Innovation: Technology, Market, and Complexity

    The article describes an innovative metrizable idea for systemic assessments of product quality within the baking industry. Complex product quality analysis requires the employment of metrizability criteria for factors that impact the quality of the product, and these are called determinants. Therefore, such analysis is only possible with the use of systems engineering. A system represents the potential of a manufacturing process, of major impact on quality. Composites of the manufacturing process make up the determinants of bread quality, grouped into three sets: raw materials, manufacturing technology, and manufacturing organization and technique. This paper also contains methodological implications for the construction of algorithms for manufacturing process potential determinants. Metrizable product quality assessment is a very important issue in the context of its implementation in manufacturing companies. Its use allows for obtaining comprehensive data on the quality status of a product. It is an important tool for analyzing and forecasting modern quality trends. The method presented in the article is new, innovative, and practical; and its vector representation may prove useful in Quality 4.0. The method could be an important point of reference for managers, directors, and decision makers who must determine the best metrizability criteria for systemic product quality assessments, and could prove useful in Industry 4.0 in the bakery industry. The main value of the paper is the presentation of a new, extensive method for systemic assessments of product quality based on vector analysis in industrial organization. We trialed the method in the baking industry. We concluded that the method is a contribution to management science, especially in the field of quality management, because this approach is not used in business and is not described in relevant international literature.

  • Sztuczna inteligencja w onkologii - nowe narzędzia do diagnostyki i medycyny spersonalizowanej
    • Krzysztof Pastuszak
    • Michał Żuk
    • Anna Supernat
    2021

    statnie dekady doprowadziły do rozwoju zaawansowanych technologii badawczych, cechujących się wysoką przepustowością. Zmienia to oblicze medycyny, doprowadzając do generowania ogromnej ilości danych. Z każdym kolejnym rokiem przybywa pacjentów onkologicznych, a zebrane informacje o pacjentach przekraczają możliwości lekarzy i naukowców w zakresie samodzielnej analizy tzw. big data. Właśnie dlatego świat nauki coraz częściej zwraca się ku algorytmom sztucznej inteligencji (AI, ang. – artificial intelligence).

  • Święto Otwartej Nauki w Bibliotece Politechniki Gdańskiej w ramach Open Access Week 2021
    • Kamila Kokot-Kanikuła
    • Agnieszka Szymik
    2021 Full text Pismo PG

    W dniach 25–31 października 2021 roku odbyła się kolejna edycja Open Access Week, imprezy w Polsce znanej jako Tydzień Otwartej Nauki. Biblioteka PG aktywnie włączyła się w promocję tego naukowego święta poprzez organizację webinariów, prezentacji i spotkań.

  • Tacit knowledge awareness and sharing as a focal part of knowledge production, Polish-US view on IT, healthcare, and construction industry
    • Wioleta Kucharska
    2021

    In the knowledge economy era, knowledge production and dissemination are of key interest to individuals, organizations, and economies. Tacit knowledge results from experience, leading to innovation. The learning culture can facilitate the transformation of errors into experiences. This study explores whether mistake acceptance facilitates tacit knowledge awareness and sharing in the information technology, healthcare, and construction industries in Poland and the United States. The findings show the influence of mistake acceptance on knowledge production and the differences between countries and industries. The US showed a higher level of mistake acceptance, which was similar across the three industries, than did Poland, which showed differences between sectors. In general, the higher the acceptance of mistakes, the greater the effect of tacit knowledge awareness on sharing. This study shows that there is no knowledge production without learning and no learning without mistake acceptance.

  • Tailoring properties of indium tin oxide thin films for their work in both electrochemical and optical label-free sensing systems
    • Petr Sezemsky
    • Dariusz Burnat
    • Jiri Kratochvil
    • Harm Wulff
    • Angela Kruth
    • Katarzyna Lechowicz
    • Monika Janik
    • Robert Bogdanowicz
    • Martin Cada
    • Zdenek Hubicka
    • Paweł Niedziałkowski
    • Wioleta Białobrzeska
    • Vitezslav Stranak
    • Mateusz Śmietana
    2021 Full text SENSORS AND ACTUATORS B-CHEMICAL

    This work is devoted to the identification properties of indium tin oxide (ITO) thin films responsible for their possible application in combined optical and electrochemical label-free sensing systems offering enhanced functionalities. Since any post-processing would make it difficult to identify direct relation between deposition parameters and properties of the ITO films, especially when deposition on temperature-sensitive substrates is considered, the films were deposited using reactive high power impulse magnetron sputtering (HiPIMS) at low temperature and with no post-deposition annealing. We focused mainly on the impact of reactive gases, such as oxygen or nitrogen introduced to the process chamber, on control over plasma parameters and subsequently properties of the films. The properties of the films were investigated using X-ray diffractometry, spectroscopic ellipsometry, four-point probe, and cyclic voltammetry. For presenting optical sensing capabilities, the tailored ITO films in addition to silicon and glass wafers were also deposited on the core of optical fibers to induce the lossy-mode resonance (LMR) phenomenon. The existence of specific deposition conditions resulting in ITO film properties offering both high-quality electrochemical and LMR responses has been experimentally proven. It has been found that the crystalline structure of ITO plays a key role in the determination of both the sensing capabilities. Finally, label-free sensing of antibody-antibody interactions in both optical and electrochemical domains for the sensor with tailored ITO film has been shown.

  • Tax Policy Tools of Selected European Countries as a Mechanism for Counteracting the Effects of the Crisis Caused by the COVID-19 Disease Pandemic
    • Piotr Kasprzak
    • Jerzy Frankowski
    2021

    Crises play an important role in a economics life. They are common and it is impossible to omit them. This following study investigates the concept of ‘crisis’ in the context of economic situation. This text describes the most important financial crises that took place in the past. After that authors passes on a detailed analysis of the actual corona-crisis and the way that it affects the economy globally. The main goal of this study is to show the European state governments reactions and action to this unusual crisis that were made in the context of tax regulations. In conclusion the target was reached what resulted in this study.

  • T-colorings, divisibility and circular chromatic number
    • Robert Janczewski
    • Anna Maria Trzaskowska
    • Krzysztof Turowski
    2021 Full text Discussiones Mathematicae Graph Theory

    Let T be a T-set, i.e., a finite set of nonnegative integers satisfying 0 ∈ T, and G be a graph. In the paper we study relations between the T-edge spans espT (G) and espd⊙T (G), where d is a positive integer and d ⊙ T = {0 ≤ t ≤ d (max T + 1): d |t ⇒ t/d ∈ T} . We show that espd⊙T (G) = d espT (G) − r, where r, 0 ≤ r ≤ d − 1, is an integer that depends on T and G. Next we focus on the case T = {0} and show that espd⊙{0} (G) = ⌈d(χc(G) − 1)⌉, where χc(G) is the circular chromatic number of G. This result allows us to formulate several interesting conclusions that include a new formula for the circular chromatic number χc(G) = 1 + inf espd⊙{0} (G)/d: d ≥ 1 and a proof that the formula for the T-edge span of powers of cycles, stated as conjecture in [Y. Zhao, W. He and R. Cao, The edge span of T-coloring on graph C d n , Appl. Math. Lett. 19 (2006) 647–651], is true.

  • Technical and Economic Analysis of the Supercritical Combined Gas-Steam Cycle
    • Marcin Jamróz
    • Marian Piwowarski
    • Paweł Ziemiański
    • Gabriel Pawlak
    2021 Full text ENERGIES

    Combined cycle power plants are characterized by high efficiency, now exceeding 60%. The record-breaking power plant listed in the Guinness Book of World Records is the Nishi-Nagoya power plant commissioned in March 2018, located in Japan, and reaching the gross efficiency of 63.08%. Research and development centers, energy companies, and scientific institutions are taking various actions to increase this efficiency. Both the gas turbine and the steam turbine of the combined cycle are modified. The main objective of this paper is to improve the gas-steam cycle efficiency and to reach the efficiency that is higher than in the record-breaking Nishi-Nagoya power plant. To do so, a number of numerical calculations were performed for the cycle design similar to the one used in the Nishi-Nagoya power plant. The paper assumes the use of the same gas turbines as in the reference power plant. The process of recovering heat from exhaust gases had to be organized so that the highest capacity and efficiency were achieved. The analyses focused on the selection of parameters and the modification of the cycle design in the steam part area in order to increase overall efficiency. As part of the calculations, the appropriate selection of the most favorable thermodynamic parameters of the steam at the inlet to the high-pressure (HP) part of the turbine (supercritical pressure) allowed the authors to obtain the efficiency and the capacity of 64.45% and about 1.214 GW respectively compared to the reference values of 63.08% and 1.19 GW. The authors believe that efficiency can be improved further. One of the methods to do so is to continue increasing the high-pressure steam temperature because it is the first part of the generator into which exhaust gases enter. The economic analysis revealed that the difference between the annual revenue from the sale of electricity and the annual fuel cost is considerably higher for power plants set to supercritical parameters, reaching approx. USD 14 million per annum. It is proposed that investments in adapting components of the steam part to supercritical parameters may be balanced out by a higher profit.

  • Techniki wielokanałowe wykorzystywane w koncertach i nagraniach muzycznych na odległość
    • Bartłomiej Mróz
    • Bożena Kostek
    • Piotr Odya
    2021

    W czasie pandemii koronawirusa COVID-19 nowego znaczenia nabrały możliwości transmisji dźwięku z obrazem – zwłaszcza do pracy zdalnej, która w przypadku muzyków jest szczególnym wyzwaniem zarówno w kontekście wspólnych ćwiczeń i prób, jak i koncertów. Wynikła konieczność wieloźródłowego połączenia ujawniła potrzebę uprzestrzennienia dźwięku w celu łatwiejszej lokalizacji źródeł dźwięku. Tworzenie zdalnych nagrań muzycznych stało się obecnie niepowtarzalną okazją do produkcji wielokanałowych, przestrzennych, wykorzystujących techniki ambisoniczne i binauralne. Techniki te umożliwiają stworzenie nowych, immersyjnych doznań dla słuchaczy. W rozdziale przedstawiono zrealizowane nagrania ambisoniczne Akademickiego Chóru Politechniki Gdańskiej. Zawarto opis związany z warsztatem realizatora dźwięku i obrazu oraz omówiono problemy związane z synchronizacją dźwięku. W pierwszej kolejności przedstawiono krótko podstawy teoretyczne ambisonii. Podano również plan dalszych prac, które będą stanowić rozwinięcie wykonanych nagrań w kontekście ich oceny.

  • Technologie cyfrowe w rozwoju współpracy biznes-uczelnie na przykładzie sektora bio-farmaceutycznego w świecie vuca
    • Sylwia Sieracka
    2021

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  • TECHNOLOGY OF CREATING AND USAGE OF PROECOLOGICAL BLOCK EMPTYSEED
    • Jan Cudzik
    • Konstancja Olszewska
    2021 Full text Przestrzeń i Forma

    Nowadays, finding natural substitutes for mass-produced materials is one of the main tasks faced by scientists and designers. There is an increasing emphasis on the theme of ecology and the need for sustainability. Variants and methods are sought which will create environmentally friendly materials in a fast, relatively inexpensive and ecological way. The aim of this paper is to present different proposals of natural building materials and to demonstrate the research process in the search for an environmentally friendly facade material, analyzing it in terms of strength, durability and aesthetics. One of the reasons for this is the steadily deteriorating environmental conditions. Thus, architects strive to improve environmental safety.

  • Temperature Fiber-Optic Sensor with ZnO ALD Coating
    • Paulina Listewnik
    2021 Full text Engineering Proceedings

    This study presents a microsphere-based fiber-optic sensor with a ZnO Atomic Layer Deposition (ALD) coating thickness of 100 nm for temperature measurements. Metrological properties of the sensor were investigated over the temperature range of 100 °C to 300 °C, with a 10 °C step. An interferometric signal is used to control whether the microstructure is whole. Spectrum shift of a reflected signal is used to ascertain changes in the measured parameter. With changing temperature, the peak position of a reflected signal also changes. The R2 coefficient of the presented sensor indicates a good linear fit of over 0.99 to the obtained data. The sensitivity of the sensor investigated in this study equals 0.019 nm/°C.

  • Tensile modulus of human orbital wall bones cut in sagittal and coronal planes
    • Krzysztof Żerdzicki
    • Paweł Lemski
    • Paweł Kłosowski
    • Andrzej Skorek
    • Marcin Zmuda Trzebiatowski
    • Mateusz Koberda
    2021 Full text PLOS ONE

    In the current research, 68 specimens of orbital superior and/or medial walls taken from 33 human cadavers (12 females, 21 males) were subjected to uniaxial tension untill fracture. The samples were cut in the coronal (38 specimens) and sagittal (30 specimens) planes of the orbital wall. Apparent density (ρapp), tensile Young’s modulus (E-modulus) and ultimate tensile strength (UTS) were identified. Innovative test protocols were used to minimize artifacts and analyze the obtained data: (1) grips dedicated to non-symmetrical samples clamping were applied for mechanical testing, (2) non-contact measuring system of video-extensometer was employed for displacement registration, (3) ink imprint technique coupled with CAD analysis was applied to precisely access the cross-sectional areas of tested samples. With regard to a pooled group, apparent density for the coronal and sagittal cut plane was equal 1.53 g/cm3 and 1.57 g/cm3, tensile Young’s modulus 2.36 GPa and 2.14 GPa, and ultimate tensile strength 12.66 MPa and 14.35 MPa, respectively. No significant statistical differences (p > 0.05) were found for all the analyzed parameters when comparing coronal and sagittal plane cut groups. These observations confirmed the hypothesis that direction of sample cut does not affect the mechanical response of the orbital wall tissue, thus suggesting that mechanical properties of orbital wall bone show isotropic character.

  • Tensile validation tests with failure criteria comparison for various GFRP laminates
    • Tomasz Wiczenbach
    • Tomasz Ferenc
    2021 Full text Archives of Civil Engineering

    The paper studies the mechanical properties of glass fibre reinforced polymers (GFRP) with various types and orientation of reinforcement. Analyzed specimens manufactured in the infusion process are made of polymer vinyl ester resin reinforced with glass fibres. Several samples were examined containing different plies and various fibres orientation [0, 90] or [+45, –45]. To assess the mechanical parameters of laminates, a series of experimental tests were carried out. The samples were subjected to the uniaxial tensile tests, which allowed us to obtain substitute parameters, such as modulus of elasticity or strength. After all, results from experiments were used to validate the numerical model. A computational model was developed employing ABAQUS software using the Finite Element Method (FEM). The analysis was performed to verify and compare the results obtained from numerical calculations with the experiments. Additionally, the following failure criteria were studied, based on the index of failure IF Maximum Stress, Maximum Strain, Tsai–Hill, and Tsai–Wu. The results confirmed the assumptions made for the footbridge's design purpose, which is made using examined material. Moreover, comparing the experimental and numerical results found that in the linear-elastic range of the material, they are consistent, and there is no significant difference in results.

  • TensorHive: Management of Exclusive GPU Access for Distributed Machine Learning Workloads
    • Paweł Rościszewski
    • Michał Martyniak
    • Filip Schodowski
    2021 Full text JOURNAL OF MACHINE LEARNING RESEARCH

    TensorHive is a tool for organizing work of research and engineering teams that use servers with GPUs for machine learning workloads. In a comprehensive web interface, it supports reservation of GPUs for exclusive usage, hardware monitoring, as well as configuring, executing and queuing distributed computational jobs. Focusing on easy installation and simple configuration, the tool automatically detects the available computing resources and monitors their utilization. Reservations granted on the basis of flexible access control settings are protected by pluggable violation hooks. The job execution module includes auto-configuration templates for distributed neural network training jobs in frameworks such as TensorFlow and PyTorch. Documentation, source code, usage examples and issue tracking are available at the project page: https://github.com/roscisz/TensorHive/

  • TEST METHOD FOR DETERMINING THE CHEMICAL EMISSIONS OF A MARINE DIESEL ENGINE EXHAUST IN OPERATION
    • Zbigniew Korczewski
    2021 Full text Polish Maritime Research

    The article briefly describes the problem of air pollution caused by sea-going ships and the resulting restrictions on the emission of toxic and harmful chemical compounds in the exhaust of marine engines, introduced by the International Maritime Organization (IMO) under the International Convention for the Prevention of Sea Pollution from Ships (MARPOL 73/78). Such emissions provide a significant metrological problem, not only for the owners of operating sea- going ships, but also for shipyards, maritime administration offices and environmental protection inspectors. For this reason, the article’s author is developing research issues related to the diagnosing the exhaust emissions of marine engines under operating conditions, i.e. with limited control (measurement) susceptibility. This is particularly important in the period of intensive implementation of a new category of marine fuel, so-called modified fuels with low sulphur content. As part of the problem, a computational model of the parameters characterising the exhaust emissions of a marine engine in operation is presented in this article. This model is based on the measurement of the engine’s control parameters, using a standard (stationary) measurement system and a portable diagnostic system, configured for the purpose of this research. Presented here are representative measurements and calculation results (both obtained by the author and provided by the manufacturer) from the chemical exhaust gas emissivity of one of the ship engines operated. These confirm the adequacy of the calculation model developed and the diagnostic effectiveness of the measuring equipment applied. The methodology developed for experimental testing may also be implemented for the operation of other types of marine engines, provided that the basic chemical composition of the fuel supply and the engine load characteristics and hourly fuel consumption are known. Moreover, there is the possibility of indicating the cylinders and measuring the chemical composition of exhaust gases in the high-temperature part of the exhaust duct.

  • Testing of Software for the Planning of a Linear Object GNSS Measurement Campaign under Simulated Conditions
    • Sławomir Figiel
    • Cezary Specht
    • Marek Moszyński
    • Andrzej Stateczny
    • Mariusz Specht
    2021 Full text ENERGIES

    The precision of a linear object measurement using satellite techniques is determined by the number and the relative position of the visible satellites by the receiver. The status of the visible constellation is described by DOP. The obtained geometric coefficient values are dependent on many variables. When determining these values, field obstacles at the receiver location and satellite positions changing with time must be taken into account. Carrying out a series of surveys as part of a linear object GNSS measurement campaign requires the optimisation problem to be solved. The manner of the inspection vehicle’s movement should be determined in such a way that the surveys are taken only within the pre-defined time frames and that the geometric coefficient values obtained at subsequent points of the route are as low as possible. The purpose of this article is to develop a software for the planning of a linear object GNSS measurement campaign to implemented in motion and taking into account the terrain model and its coverage. Additionally, it was determined how much the developed program improves DOP values on the planned route under simulated conditions. This software has no equivalent elsewhere in the world, as the current solutions for the planning of a GNSS measurement campaign, e.g., Trimble GNSS Planning, GNSS Mission Planning, or GPS Navigation Toolbox, allow the satellite constellation geometry to be analysed exclusively for specific coordinates and at a specific time. Analysis of the obtained simulation test results indicates that the campaign implementation in accordance with the pre-determined schedule significantly improves the quality of the recorded GNSS data. This is particularly noticeable when determining the position using the GPS and GLONASS satellite constellations at the same time. During the tests conducted on the road along a three-kilometre-long route in Gdańsk, the average value of the obtained PDOP decreased by 22.17% thanks to using the software to plan a linear object GNSS measurement campaign. The largest drop in the geometric coefficient values was noted for an area characterised by a very large number of field obstacles. Under these conditions, the PDOP value decreased by approx. 25%. In areas characterised by a small number of field obstacles (single trees in the vicinity of the track, clusters of trees and buildings located along the track), the changes in the PDOP were slightly smaller and amounted to several percent.

  • Testing of the longest span soil-steel bridge in Europe – new quality in measurements
    • Mikołaj Miśkiewicz
    • Bartosz Sobczyk
    • Paweł Tysiąc
    2021

    The article describes interdisciplinary and comprehensive diagnostic tests of final bridge inspection and acceptance proposed for a soil – steel bridge made of corrugated sheets, being the European span length record holder (25.74 m). As an effect of an original concept a detailed and precise information about the structure response was collected. The load test design was based on the nonlinear numerical simulations performed by means of FEM. The in-situ measurements were done with aid of: inductive sensors, optical total station, terrestrial laser scanner. The results produced by terrestrial laser scanning were used to build a precise image of structure deformation in 3D space during the tests. The precision of laser mapping was additionally significantly increased by means of image tracing (vectorization) and calibration of results through parallel verification of the collected data with the values coming from optic total station and inductive sensors. Thus, new quality in measurements is introduced.

  • Testing Stability of Digital Filters Using Optimization Methods with Phase Analysis
    • Damian Trofimowicz
    • Tomasz Stefański
    2021 Full text ENERGIES

    In this paper, novel methods for the evaluation of digital-filter stability are investigated. The methods are based on phase analysis of a complex function in the characteristic equation of a digital filter. It allows for evaluating stability when a characteristic equation is not based on a polynomial. The operation of these methods relies on sampling the unit circle on the complex plane and extracting the phase quadrant of a function value for each sample. By calculating function-phase quadrants, regions in the immediate vicinity of unstable roots (i.e., zeros), called candidate regions, are determined. In these regions, both real and imaginary parts of complex-function values change signs. Then, the candidate regions are explored. When the sizes of the candidate regions are reduced below an assumed accuracy, then filter instability is verified with the use of discrete Cauchy’s argument principle. Three different algorithms of the unit-circle sampling are benchmarked, i.e., global complex roots and poles finding (GRPF) algorithm, multimodal genetic algorithm with phase analysis (MGA-WPA), and multimodal particle swarm optimization with phase analysis (MPSO-WPA). The algorithms are compared in four benchmarks for integer- and fractional-order digital filters and systems. Each algorithm demonstrates slightly different properties. GRPF is very fast and efficient; however, it requires an initial number of nodes large enough to detect all the roots. MPSO-WPA prevents missing roots due to the usage of stochastic space exploration by subsequent swarms. MGA-WPA converges very effectively by generating a small number of individuals and by limiting the final population size. The conducted research leads to the conclusion that stochastic methods such as MGA-WPA and MPSO-WPA are more likely to detect system instability, especially when they are run multiple times. If the computing time is not vitally important for a user, MPSO-WPA is the right choice, because it significantly prevents missing roots.

  • The adaptive spatio-temporal clustering method in classifying direct labor costs for the manufacturing industry
    • Mateusz Kalinowski
    • Jakub Baran
    • Paweł Weichbroth
    2021 Full text

    Employee productivity is critical to the profitability of not only the manufacturing industry. By capturing employee locations using recent advanced tracking devices, one can analyze and evaluate the time spent during a workday of each individual. However, over time, the quantity of the collected data becomes a burden, and decreases the capabilities of efficient classification of direct labor costs. However, the results obtained from performed experiments show that the existing clustering methods have failed to deliver satisfactory results by taking advantage of spatial data. In contrast to this, the adaptive spatio-temporal clustering (ASTC) method introduced in this paper utilizes both spatial and time data, as well as prior data concerning the position and working status of deployed machines inside a factory. The results show that our method outperforms the bucket of three well-known methods, namely DBSCAN, HDBSCAN and OPTICS. Moreover, in a series of experiments, we also validate the underlying assumptions and design of the ASTC method, as well as its efficiency and scalability. The application of the method can help manufacturing companies analyze and evaluate employees, including the productive times of day and most productive locations.

  • The added value of using the HEPA PAT for physical activity policy monitoring: a four-country comparison
    • Peter Gelius
    • Sven Messing
    • Sarah Forberger
    • Jeroen Lakerveld
    • Fiona Mansergh
    • Wanda Wendel-Vos
    • Joanna Żukowska
    • Catherine Woods
    2021 Full text Health Research Policy and Systems

    Background Public policy is increasingly recognized as an important component of physical activity promotion. This paper reports on the current status of physical activity policy development and implementation in four European countries based on the Health-Enhancing Physical Activity Policy Audit Tool (HEPA PAT) developed by WHO. It compares the findings to previous studies and discusses the general utility of this tool and its unique features in relation to other instruments. Methods The study was conducted as part of the Policy Evaluation Network (www.jpi-pen.eu) in Germany, Ireland, the Netherlands and Poland. Data collection built upon information obtained via the EU Physical Activity Monitoring Framework survey, additional desk research and expert opinion. Data analysis employed Howlett’s policy cycle framework to map and compare national physical activity policies in the four countries. Results In all countries under study, policy agenda-setting is influenced by prevalence data from national health monitoring systems, and the sport and/or health sector takes the lead in policy formulation. Key policy documents were located mainly in the health sector but also in sport, urban design and transport. Physical activity programmes implemented to meet policy objectives usually cover a broad range of target groups, but currently only a small selection of major policies are evaluated for effectiveness. National experts made several suggestions to other countries wishing to establish physical activity policies, e.g. regarding cross-sectoral support and coordination, comprehensive national action plans, and monitoring/surveillance. Conclusions This study provides a detailed overview of physical activity policies in the four countries. Results show that national governments are already very active in the field but that there is room for improvement in a number of areas, e.g. regarding the contribution of sectors beyond sport and health. Using the HEPA PAT simultaneously in four countries also showed that procedures and timelines have to be adapted to national contexts. Overall, the instrument can make an important contribution to understanding and informing physical activity policy, especially when used as an add-on to regular monitoring tools like the EU HEPA Monitoring Framework.

  • The Analysis of Cross-Polarisation Discrimination for Body Area Networks in Cylindrical Metallic Environment
    • Andrzej Ambroziak
    • Krzysztof Cwalina
    • Piotr Rajchowski
    2021

    The analysis of cross-polarisation discrimination for Body Area Networks in an untypical environment of cylindrical metallic room has been performed in the paper. This analysis was done based on the measurements carried out for dynamic narrowband off-body channels operating at the frequency of 2.45 GHz. The results have shown that there is a strong dependence of the depolarisation effect on the existence of direct component in the radio channel.

  • The assessment of metrological properties of segmental orifice based on simulations and experiments
    • Anna Golijanek-Jędrzejczyk
    • Andrzej Mrowiec
    • Robert Hanus
    • Marcin Zych
    • Marcin Heronimczak
    • Dariusz Świsulski
    2021 Full text MEASUREMENT

    Segmental orifices are often used to measure flows of heterogeneous mixtures, especially in flow meters in the power industry, for example. The orifice (with module m= 0.25) was installed in a stainless-steel pipe with internal diameter of 50 mm, placed in a hydraulic water system. The research was performed for Reynolds numbers ranging from 9,000 to 17,000. The flow characteristics of this orifice obtained based on simulation in SolidWorks Flow Simulation 2014 and experimental data were compared with standard-based calculations. It was determined that relative differences between the obtained flow characteristics did not exceed 1.5% for the experiment and 5.1% for the simulation. The article also presents the results of estimated uncertainty for mass flow measurement qm using the analytical method and the Monte Carlo simulations. The results for both methods proved that the relative expanded uncertainty Urel(qm) does not exceed 1.8% for the tested orifice.

  • The bile salt content of human bile impacts on simulated intestinal proteolysis of β-lactoglobulin
    • Dorota Dulko
    • Robert Staroń
    • Lukasz Krupa
    • Neil Rigby
    • Alan Mackie
    • Krzysztof Gutkowski
    • Andrzej Wasik
    • Adam Macierzanka
    2021 Full text FOOD RESEARCH INTERNATIONAL

    The gastrointestinal hydrolysis of food proteins has been portrayed in scientific literature to predominantly depend on the activity and specificity of proteolytic enzymes. Human bile has not been considered to facilitate proteolysis in the small intestine, but rather to assist in intestinal lipolysis. However, human bile can potentially influence proteins that are largely resistant to gastric digestion, and which are mainly hydrolysed after they have been transferred to the small intestine. We used purified and food-grade bovine milk β-lactoglobulin (βLg) to assess the impact of bile salts (BS) on the in vitro gastrointestinal digestion of this protein. Quantitative analysis showed that the proteolysis rate increased significantly with increasing BS concentration. The effect was consistent regardless of whether individual BS or real human bile samples, varying in BS concentrations, were used. The total BS content of bile was more important than its BS composition in facilitating the proteolysis of βlg. We also show that the impact of human bile observed during the digestion of purified βLg and βLg-rich whey protein isolate can be closely replicated by the use of individual BS mixed with phosphatidylcholine. This could validate simple BS/phosphatidylcholine mixtures as human-relevant substitutes of difficult-to-obtain human bile for in vitro proteolysis studies.

  • The cement-bone bond is weaker than cement-cement bond in cement-in-cement revision arthroplasty. A comparative biomechanical study
    • Marcin Ceynowa
    • Krzysztof Żerdzicki
    • Paweł Kłosowski
    • Maciej Zrodowski
    • Rafał Pankowski
    • Marek Rocławski
    • Tomasz Mazurek
    2021 Full text PLOS ONE

    This study compares the strength of the native bone-cement bond and the old-new cement bond under cyclic loading, using third generation cementing technique, rasping and contamination of the surface of the old cement with biological tissue. The possible advantages of additional drilling of the cement surface is also taken into account. Femoral heads from 21 patients who underwent a total hip arthroplasty performed for hip arthritis were used to prepare bone-cement samples. The following groups of samples were prepared. A bone— cement sample and a composite sample of a 6 weeks old cement part attached to new cement were tested 24 hours after preparation to avoid bone decay. Additionally, a uniform cement sample was prepared as control (6 weeks polymerization time) and 2 groups of cement-cement samples with and without anchoring drill hole on its surface, where the old cement polymerized for 6 weeks before preparing composite samples and then another 6 weeks after preparation. The uniaxial cyclic tension-compression tests were carried out using the Zwick-Roell Z020 testing machine. The uniform cement sample had the highest ultimate force of all specimens (n = 15; Rm = 3149 N). The composite cement sample (n = 15; Rm = 902 N) had higher ultimate force as the bone-cement sample (n = 31; Rm = 284 N; p <0.001). There were no significant differences between composite samples with 24 hours (n = 15; Rm = 902 N) and 6 weeks polymerization periods (n = 22; Rm = 890 N; p = 0.93). The composite cement samples with drill hole (n = 16; Rm = 607 N) were weaker than those without it (n = 22; Rm = 890 N; p < 0.001). This study shows that the bond between the old and new cement was stronger than the bond between cement and bone. This suggests that it is better to leave the cement that is not loosened from the bone and perform cement in cement revision, than compromising bone stock by removal of the old cement with the resulting weaker cement-bone interface. The results support performing cement-in-cement revision arthroplasty The drill holes in the old cement mantle decrease cement binding strength and are not recommended in this type of surgery.

  • The Chemical and Biological Properties of Nanohydroxyapatite Coatings with Antibacterial Nanometals, Obtained in the Electrophoretic Process on the Ti13Zr13Nb Alloy
    • Michał Bartmański
    • Łukasz Pawłowski
    • Anna Belcarz
    • Agata Przekora
    • Grazyna Ginalska
    • Gabriel Strugała
    • Bartłomiej Cieślik
    • Anna Pałubicka
    • Andrzej Zieliński
    2021 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    The risk of an early inflammation after implantation surgery of titanium implants has caused the development of different antimicrobial measures. The present research is aimed at characterizing the effects of nanosilver and nanocopper dispersed in the nanohydroxyapatite coatings, deposited on the Ti13Zr13Nb alloy, and on the chemical and biological properties of the coatings.The one-stage deposition process was performed by the electrophoretic method at different contents of nanomaterials in suspension. The surface topography of the coatings was examined with scanning electron microscopy. The wettability was expressed as the water contact angle. The corrosion behavior was characterized by the potentiodynamic technique. The release rate of copper and silver into the simulated body fluid was investigated by atomic absorption spectrometry. The antibacterial efficiency was evaluated as the survivability and adhesion of the bacteria and the growth of the biofilm. The cytotoxicity was assessed for osteoblasts. The results demonstrate that silver and copper increase the corrosion resistance and hydrophilicity. Both elements together effectively kill bacteria and inhibit biofilm growth but appear to be toxic for osteoblasts. The obtained results show that the nanohydroxyapatite coatings doped with nanosilver and nanocopper in a one-stage electrophoretic process can be valuable for antibacterial coatings.

  • The Cluster Organization. Analyzing the Development of Cooperative Relationships
    • Anna Lis
    • Adrian Lis
    2021

    Cluster organizations are becoming more and more popular, both in developing and developed countries. Considering the development of cluster policy and the related dynamic growth of cluster initiatives in the world, the lack of sufficient knowledge on the development of cooperation in cluster organizations inhibits their development and, in many cases, causes their complete disintegration. 　 The book provides new important elements to the current system of knowledge, filling in cognitive and research gaps in the scientific literature on problems related to cooperation in cluster organizations. The most valuable features for the reader concern the epistemological, methodological, and application aspects. The new element includes a theoretical concept, which refers to the trajectory of development of cooperative relationships in cluster organizations that facilitates the understanding and explanation of mechanisms responsible for cooperation in such organizations. 　 The concept also has great practical advantages, especially for people implementing the idea of "clustering": coordinators, facilitators, and members of cluster organizations as well as politicians and public authorities are responsible for shaping and implementing the cluster policy. It will be of value to researchers, academics, and students in fields with an interest in organizational studies, management of innovation and technology, strategic management, industrial economics, and economic geography.

  • THE COMPOSITION MODULATION EFFECT IN GaInPAs SOLID SOLUTIONS AS A MANIFESTATION OF ENERGY RESONANCE AFTER MATERIAL'S SPINODAL DECOMPOSITION
    • Pavel Moskvin
    • S.i. Skurativskyi
    • O.a. Gromovyi
    • Wojciech Sadowski
    2021 Full text Journal of Physical Studies

    The Cahn-Hilliard model concepts are extended to describe the spinodal decomposition of Ga$_x$In$_{1-x}$P$_y$As$_{1-y}$ solid solutions grown on the InP substrate. The energy of elastic deformation of the thin layer of a solid solution was calculated on the assumption of its coherent conjugation with the massive InP substrate. The excess energy of component mixing in the solid phase was modeled in accordance with the simple solution model, when the simultaneous substitution of components in the metal and metalloid sub lattices of the sphalerite structure is incorporated. The system of differential equations describing variations of the composition of a semiconductor solid solution after its spinodal decomposition was solved numerically under various thermodynamic conditions.

  • The Concept of Accuracy Analysis of the Vertical Displacements Gained from the Hydrostatic Levelling Systems’ Measurements
    • Waldemar Kamiński
    2021 Full text SENSORS

    Abstract: Nowadays, hydrostatic levelling is a widely used method for the vertical displacements’ determinations of objects such as bridges, viaducts, wharfs, tunnels, high buildings, historical buildings, special engineering objects (e.g., synchrotron), sports and entertainment halls. The measurements’ sensors implemented in the hydrostatic levelling systems (HLSs) consist of the reference sensor (RS) and sensors located on the controlled points (CPs). The reference sensor is the one that is placed at the point that (in theoretical assumptions) is not a subject to vertical displacements and the displacements of controlled points are determined according to its height. The hydrostatic levelling rule comes from the Bernoulli’s law. While using the Bernoulli’s principle in hydrostatic levelling, the following components have to be taken into account: atmospheric pressure, force of gravity, density of liquid used in sensors places at CPs. The parameters mentioned above are determined with some mean errors that influence on the accuracy assessment of vertical displacements. In the subject’s literature, there are some works describing the individual accuracy analyses of the components mentioned above. In this paper, the author proposes the concept of comprehensive determination of mean error of vertical displacement (of each CPs), calculated from the mean errors’ values of components dedicated for specific HLS. The formulas of covariances’ matrix were derived and they enable to make the accuracy assessment of the calculations’ results. The author also presented the subject of modelling of vertical displacements’ gained values. The dependences, enabling to conduct the statistic tests of received model’s parameters, were implemented. The conducted tests make it possible to verify the correctness of used theoretical models of the examined object treated as the rigid body. The practical analyses were conducted for two simulated variants of sensors’ connections in HLS. Variant no. I is the sensors’ serial connection. Variant no. II relies on the connection of each CPs with the reference sensor. The calculations’ results show that more detailed value estimations of the vertical displacements can be obtained using variant no. II.

  • The concept of suspended urban rail vehicle
    • Mateusz Kuczyk
    • Piotr Jędrzejewski
    • Paweł Załuski
    2021 Full text Pojazdy Szynowe

    Niniejsza publikacja została poświęcona szczegółowemu opisowi proponowanej przez autorów koncepcji podwieszanego pojazdu szynowego. W pierwszej kolejności przeanalizowano istniejące rozwiązania, wraz ze wskazaniem ich podstawowych wad i zalet. Następnie opisano proponowaną konstrukcję w zakresie: budowy wagonu, sposobu jego zawieszenia oraz prowadzenia po zadanym torze ruchu. Artykuł ten powstał na podstawie pracy dyplomowej pt. „Koncepcja wagonu silnikowego kolei podwieszanej”, na wydziale Mechanicznym Politechniki Gdańskiej.

  • The Conceptual Research over Low-Switching Modulation Strategy for Matrix Converters with the Coupled Reactors
    • Paweł Szczepankowski
    • Jarosław Łuszcz
    • Aleksander Usoltsev
    • Natalia Strzelecka
    • Enrique Romero-Cadaval
    2021 Full text ENERGIES

    In this paper, different Pulse Width Modulation (PWM) strategies for operating with a low-switching frequency, a topology that combines Conventional Matrix Converters (CMCs), and Coupled Reactors (CRs) are presented and discussed. The principles of the proposed strategies are first discussed by a conceptual analysis and later validated by simulation. The paper shows how the combination of CMCs and CRs could be of special interest for sharing the current among these converters’ modules, being possible to scale this solution to be a modular system. Therefore, the use of coupled reactors allows one to implement phase shifters that give the solution the ability to generate a stair-case load voltage with the desired power quality even the matrix converters are operated with a low-switching frequency close to the grid frequency. The papers also address how the volume and weight of the coupled reactors decrease with the growth of the fundamental output frequency, making this solution especially appropriate for high power applications that are supplied at high AC frequencies (for example, in airport terminals, where a supply of 400 Hz is required).

  • The construction of suspended rail vehicle bogie
    • Mateusz Kuczyk
    • Piotr Jędrzejewski
    • Paweł Załuski
    2021 Full text Pojazdy Szynowe

    Niniejsza publikacja została poświęcona szczegółowemu opisowi wózka, przeznaczonego do wykorzystania w proponowanej przez autorów koncepcji podwieszanego pojazdu szynowego. W pierwszej kolejności skrótowo opisano rzeczony pojazd, ze szczególnym naciskiem na parametry determinujące konstrukcję wózków. Następnie zostały omówione zastosowane rozwiązania konstrukcyjne w zakresie budowy poszczególnych podzespołów wózka, takich jak: zestawy kołowe, rama, dwustopniowe usprężynowanie, układ napędowy i hamulcowy. Artykuł ten powstał na podstawie pracy dyplomowej pt. „Koncepcja wagonu silnikowego kolei podwieszanej”, na wydziale Mechanicznym Politechniki Gdańskiej.

  • The description of non-linear interactions of wave and non-wave modes in a non-adiabatic plasma flow
    • Anna Perelomova
    2021 Full text CONTRIBUTIONS TO PLASMA PHYSICS

    The method of derivation of non-linear equations for interacting modes is explained and applied to a plasma's flow affected by a magnetic field. It is based on the linear projecting of the total perturbation field into specific variations of variables in individual modes of a flow. The method may be applied in many examples of fluid flows with different mechanisms of non-adiabaticity. It is of special importance in complex flows with large number of different modes. A flow of an ionized gas is one of the examples of such flows: it incorporates fast, slow magnetosonic modes, the Alfvén mode and the entropy mode. In the frames of this study, the wave vector may form an arbitrary angle urn:x-wiley:08631042:media:ctpp202100067:ctpp202100067-math-0001 with the straight equilibrium magnetic field. Thermal conduction, dynamic viscosity and a generic heating–cooling function, which is responsible for an energy inflow and radiative losses, are taken into account. Variable urn:x-wiley:08631042:media:ctpp202100067:ctpp202100067-math-0002 and plasma-β, diversity of the wave modes and a balance of different mechanisms of non-adiabaticity make the description of non-linear interaction of modes special. The non-linear excitation of the magnetosonic mode by the entropy mode is considered as an example.

  • The Determinants of False Self-Employment: A Survey of Polish Enterprises
    • Dagmara Nikulin
    2021 EASTERN EUROPEAN ECONOMICS

    The main goal of this article is to advance the emergent research on tax evasion in Poland in the form of false self-employment (FSE), in particular to identify its causes. The dependent character of some self-employed workers is a big problem in the Polish economy, which has been completely unexplored because of the lack of available data. In this article, we use data from a survey of Polish companies. Our empirical results show the highest prevalence of FSE in construction and to lesser extent in the services and retail, at micro and small firms, and at firms whose owners or managers are characterized by lower tax morality.

  • The Development of a Combined Method to Quickly Assess Ship Speed and Fuel Consumption at Different Powertrain Load and Sea Conditions
    • Przemysław Krata
    • Aleksander Kniat
    • Roberto Vettor
    • Hubert Krata
    • Carlos Guedes Soares
    2021 Full text TransNav - The International Journal on Marine Navigation and Safety of Sea Transportation

    Decision support systems (DSS) recently have been increasingly in use during ships operation. They require realistic input data regarding different aspects of navigation. To address the optimal weather routing of a ship, which is one of the most promising field of DSS application, it is necessary to accurately predict an actually attainable speed of a ship and corresponding fuel consumption at given loading conditions and predicted weather conditions. In this paper, authors present a combined calculation method to predict those values. First, a deterministic modeling is applied and then an artificial neural network (ANN) is structured and trained to quickly mimic the calculations. The sensitivity of the ANN to adopted settings is analyzed as well. The research results confirm a more than satisfactory quality of reproduction of speed and fuel consumption data as the ANN response meet the calculation results with high accuracy. The ANN-based approach, however, requires a significantly shorter time of execution. The directions of future research are outlined.

  • The Effect of Cobalt Incorporation into Nickel–Iron Oxide/(oxy)hydroxide Catalyst on Electrocatalytic Performance Toward Oxygen Evolution Reaction
    • Karolina Cysewska
    • Marcin Zając
    • Marcin Łapiński
    • Jakub Karczewski
    • Maria Rybarczyk
    • Bartosz Kamecki
    • Piotr Jasiński
    • Sebastian Molin
    2021 Energy Technology

    This work presents a study on the influence of the addition of cobalt into state-of-the-art nickel–iron (NiFe) mixed oxides/hydroxides/(oxy)hydroxides on their structural and morphological properties, and oxygen evolution reaction (OER) catalytic activity. A one-step electrodeposition process is performed without any additives to fabricate NiFe and x cobalt-doped nickel/iron (xCoNiFe) layer-double-hydroxide catalysts directly on nickel foam. The addition of cobalt nitrate in the synthesis solution significantly affects the final form of the catalyst: the addition of 2 mm cobalt nitrate into the aqueous solution of 4 mm nickel and iron nitrate stabilizes the electrochemical synthesis of the catalyst, which leads to the formation of a homogenously spread 3D interconnected structure with a high electroactive surface area (0.07 cm2, 1.1 m2 cm−2: including nickel foam substrate); it induces the formation of Ni3+ desirable for the formation of the catalytically active (oxy)hydroxides, which is not observed for the state-of-the-art NiFe. The significant role of the addition of cobalt translates into improved preliminary OER catalytic stability and activity of the catalyst with an onset potential of 1.40 V, overpotential of 224 mV determined at 10 mA cm−2, and only 0.7% loss in stability after 22 h working in alkaline conditions compared with the initial parameters.

  • The Effect of Conjugation with Octaarginine, a Cell-Penetrating Peptide on Antifungal Activity of Imidazoacridinone Derivative
    • Kamila Rząd
    • Ewa Paluszkiewicz
    • Damian Neubauer
    • Mateusz Olszewski
    • Katarzyna Kozłowska-Tylingo
    • Wojciech Kamysz
    • Iwona Gabriel
    2021 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Acridine cell-penetrating peptide conjugates are an extremely important family of compounds in antitumor chemotherapy. These conjugates are not so widely analysed in antimicrobial therapy, although bioactive peptides could be used as nanocarriers to smuggle antimicrobial compounds. An octaarginine conjugate of an imidazoacridinone derivative (Compound 1-R8) synthetized by us exhibited high antifungal activity against reference and fluconazole-resistant clinical strains (MICs ≤ 4 μg mL−1). Our results clearly demonstrate the qualitative difference in accumulation of the mother compound and Compound 1-R8 conjugate into fungal cells. Only the latter was transported and accumulated effectively. Microscopic and flow cytometry analysis provide some evidence that the killing activity of Compound 1-R8 may be associated with a change in the permeability of the fungal cell membrane. The conjugate exhibited low cytotoxicity against human embryonic kidney (HEK-293) and human liver (HEPG2) cancer cell lines. Nevertheless, the selectivity index value of the conjugate for human pathogenic strains remained favourable and no hemolytic activity was observed. The inhibitory effect of the analysed compound on yeast topoisomerase II activity suggested its molecular target. In summary, conjugation with R8 effectively increased imidazoacridinone derivative ability to enter the fungal cell and achieve a concentration inside the cell that resulted in a high antifungal effect.