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Gdańsk University of Technology

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  • Synthesis of compounds with C-P-P and C=P-P bond systems based on the phospha-Wittig reaction
    • Aleksandra Ziółkowska
    • Natalia Szynkiewicz
    • Jerzy Pikies
    • Łukasz Ponikiewski
    2020 Full text DALTON TRANSACTIONS

    A reactivity study of a β-diketiminate titanium(III) phosphanylphosphido complex [MeNacNacTi(Cl){η2-P(SiMe3)-PtBu2}] (1) towards ketones such as benzophenone, 9-fluorenone, acetophenone, cyclopentanone, cyclohexanone and cycloheptanone is reported. The reactions of 1 with aromatic ketones (without α-protons) directly lead to the Ti(III) complex [MeNacNacTi(μ2-Cl)(OSiMe3)] (5) as well as Ti(IV) complexes with the pinacol condensation product [MeNacNacTi(OSiMe3)(η2-pinacolate)] (3), and phosphanylphosphaalkenes Ph2C=P-PtBu2 (2) and (fluorenyl)C=P-PtBu2 (6), respectively. The reaction with acetophenone leads to the titanium(III) complex with the aldol condensation product as ligand [MeNacNacTi(Cl){OC{Me(Ph)}CH2(C=O)Ph] (8) and in parallel to phosphanylphosphaalkene (Ph)MeC=P-PtBu2 (9) and 5. The reactions of 1 with cyclic ketones (cyclopentanone and cyclohexanone) lead to Ti(III) complexes [{(ArN=C(Me)CHC(Me)=NAr)((CH2)4CO)}Ti(Cl){PtBu2-P(SiMe3)((CH2)4CO)}] (10) and [{(ArN=C(Me)CHC(Me)=NAr)((CH2)5CO)}Ti(Cl){PtBu2-P(SiMe3)((CH2)5CO)}] (11), which are formed via successive insertion of two molecules of ketone to one molecules of 1. The stability investigation of complexes 10 and 11 in a polar solvent (THF) revealed that under these conditions, the complexes decompose, resulting in titanium(III) complexes with aldol condensation products and the expected phosphanylphosphaalkenes (CH2)4C=P-PtBu2 (10a) and (CH2)5C=P-PtBu2 (11a). In the reaction of 1 with cycloheptanone only the Ti(III) complex with the aldol condensation product [MeNacNacTi(Cl){OC(CH2)5}CH(C=O)(CH2)6] (12) was isolated. The structures 3, 5, 8, 10, 11, 11b and 12 were characterized by X-ray spectroscopy, while all the phosphanylphosphaalkenes were characterized by NMR spectroscopy.

  • Synthesis of eosin modified TiO2 film with co-exposed {001} and {101} facets for photocatalytic degradation of para-aminobenzoic acid and solar H2 production
    • Javed Khan
    • Murtaza Sayed
    • Noor S. Shah
    • Sanaullah Khan
    • Yuxin Zhang
    • Grzegorz Boczkaj
    • Hasan Khan
    • Dionysios D. Dionysiou
    2020 APPLIED CATALYSIS B-ENVIRONMENTAL

    Owing to the increasing photosensitivity and DNA damage properties of para-aminobenzoic acid (PABA), concerns have been raised over the exposure of humans to PABA. Solar light-driven photocatalysis (SPC) provides a promising solution for the effective removal of organic pollutants especially when directed towards sulfate radical (SO4−) production. Herein, we have developed a sulfite-enhanced SPC using Eosin-Y sensitized TiO2/Ti film as a photocatalyst. The removal efficiency of PABA was enhanced by coupling Eosin-Y with TiO2/Ti film as revealed from 23.6 and 48.9 % PABA degradation by reference-TiO2/solar and Eosin-TiO2/solar, respectively. The apparent rate constant of PABA degradation by Eosin-TiO2 was improved by 4.7 times in presence of 5 mM sulfite. Interestingly, Eosin-TiO2 showed appreciable H2 production rate under visible light illumination. Solar/sulfite/Eosin-TiO2 system is a promising technology for environmental sustainability by using the renewable solar energy and air pollutants since sulfite is a waste from flue gas desulfurization process.

  • Synthesis of Titanium Dioxide via Surfactant-Assisted Microwave Method for Photocatalytic and Dye-Sensitized Solar Cells Applications
    • Adam Kubiak
    • Zuzanna Bielan
    • Aleksandra Bartkowiak
    • Elżbieta Gabała
    • Adam Piasecki
    • Maciej Zalas
    • Anna Zielińska-Jurek
    • Marcin Janczarek
    • Katarzyna Siwińska-Ciesielczyk
    • Teofil Jesionowski
    2020 Full text Catalysts

    In this study, titania nanoparticles were obtained using the microwave-assisted technique. Moreover, different surfactants (PEG (Mn = 400), Pluronic P123 and Triton X−100) were used during the synthesis in order to determine their impact on the crystallinity and morphology of the final products. Subsequently, techniques such as XRD, SEM and TEM (performed in high contrast and high-resolution mode), diffuse reflectance spectroscopy (DRS), low temperature N2 sorption (BET model), FTIR and TGA were carried out. Based on the crystallinity analysis of the obtained materials, it was established that the addition of surfactants results in greater (PEG and Triton X−100) or smaller (Pluronic P123) average crystallite size. The main purpose of this study was to use the synthesized nanomaterials in the photodegradation process (in the UV light range) of the model organic pollutants – phenol (20 mg/L) and etodolac (15 mg/L). Furthermore, it was also pointed out that the dye-sensitized solar cells can be a second application for the synthesized titania nanomaterials. The photo-oxidation and photovoltaic tests have shown that the titanium dioxide obtained using the surfactant-assisted microwave method is characterized not only by better photodegradation efficiency of phenol and etodolac, but also by higher photocurrent density compared to the reference titania samples—the pristine TiO2 and commercial P25.

  • Synthesis, structural characterization, and thermal properties of Ca‐ and La‐doped soda‐lime glasses by laser melting
    • Sharafat Ali
    • Natalia Wójcik
    • Bo Jonson
    • Efstratios Kamitsos
    • Xinghua Li
    • Jian Luo
    • Doris Möncke
    2020 Full text International Journal of Applied Glass Science

    Laser melting techniques have been used in the preparation of unconventional glass compositions with high melting temperatures. Thus, we wanted to test the feasibility of using a CO2 laser in the preparation of nitrogen-rich oxynitride glasses and nitride silicate glasses. Melting from oxides and metallic raw materials, we wanted to study first glass formation and possible evaporation losses of the glass components. Two glass series were prepared and studied for their structure and thermal properties, one with Ca2+- and a higher melting La3+-doped soda-lime-silicate (SLS) series. In less than 3minutes of laser melting, spheres of up to 6mm diameter were successfully fabricated. The obtained glass samples were homogeneous and transparent in the visible region. X-ray diffraction and Raman spectroscopic analysis confirmed the amorphous nature of the synthesized samples. Sodium losses increase as calcium is added to the soda-lime-silicate glass. As expected, increasing Ca2+ or La3+ addition lead to increased depolymerization of the silicate network. Moreover, the increases in Tg with the addition of Ca2+ or La3+ ions indicating strengthening of the soda-lime-silicate glass by increasing strength of the M-O bonds of divalent and trivalent ions over monovalent sodium ions, weak Na-O bonds also resulting in significant evaporation loss during the short laser melting times. The thermal stability decreases upon addition of Ca2+ or La3+ ions to the soda-lime-silicate glasses.

  • Synthesis, structure and physical properties of new intermetallic spin glass-like compounds RE2PdGe3 (RE = Tb and Dy)
    • Leszek Litzbarski
    • Tomasz Klimczuk
    • Michał Winiarski
    2020 Full text JOURNAL OF PHYSICS-CONDENSED MATTER

    New intermetallic compounds Tb2Pd1.25Ge2.75 and Dy2Pd1.25Ge2.75 have been synthesized using the arc-melting method. The crystallographic structure and magnetic, electronic transport, and thermal properties are reported. The crystal structure obtained from powder x-ray diffraction analysis suggests that these compounds crystallize in the AlB2-type structure (space group P6/mmm, no. 191) with lattice parameters a  =  4.228 53(5)/4.230 54 (2) Å and c  =  3.942 25(9)/3.945 52(5) Å for the compounds with Tb and Dy respectively. The ac and dc magnetic susceptibility studies reveal spin-glass like behavior, with freezing temperature T f  =  10.5 K for Tb2Pd1.25Ge2.75 and 4.5 K for Dy2Pd1.25Ge2.75. These data are in good agreement with the heat capacity measurements.

  • Synthesis, thermal, structural and electrical properties of vanadium-doped lithium-manganese-borate glass and nanocomposites
    • Agata Jarocka
    • Przemysław Michalski
    • Jacek Ryl
    • Marek Wasiucionek
    • Jerzy Garbarczyk
    • Tomasz Pietrzak
    2020 Full text IONICS

    A glassy sample with a nominal formula LiMn1−3x/2VxBO3 (where x = 0.05) was synthesised using the melt-quenching method. Material was characterised by differential thermal analysis (DTA), X-ray diffactometry (XRD) at room temperature and as a function of temperature (HT-XRD), X-ray photoelectron spectroscopy (XPS), impedance spectroscopy (IS) and scanning electron microscopy (SEM). Dependences of glass transition and crystallisation temperatures on the heating rate in DTA experiments were determined. The initial value of electrical conductivity of the glass was 1.4×10−15 Scm−1. It was significantly increased by a proper thermal nanocrystallisation. The maximum value was higher by 6 orders of magnitude and reached 2.6×10−9 Scm−1 at room temperature. Expected crystalline phases (i.e. monoclinic and hexagonal LiMnBO3) upon heating were identified and assigned to thermal events observed with DTA. Microstructure of nanocrystalline samples observed by SEM revealed nanocrystalline grains noticeably smaller than 100 nm. Results explaining nanocrystallisation process are coherent.

  • Synthetic strategies in construction of organic low molecular-weight carrier-drug conjugates
    • Andrzej Skwarecki
    • Michał Nowak
    • Maria Milewska
    2020 Full text BIOORGANIC CHEMISTRY

    Inefficient transportation of polar metabolic inhibitors through cell membranes of eukaryotic and prokaryotic cells precludes their direct use as drug candidates in chemotherapy. One of the possible solutions to this problem is application of the ‘Trojan horse’ strategy, i.e. conjugation of an active substance with a molecular carrier of organic or inorganic nature, facilitating membrane penetration. In this work, the synthetic strategies used in rational design and preparation of conjugates of bioactive agents with three types of organic low molecular-weight carriers have been reviewed. These include iron-chelating agents, siderophores and cell-penetrating peptides. Moreover, a less known but very promising “molecular umbrella” conjugation strategy has been presented. Special attention has been paid on appropriate linking strategies, especially these allowing intracellular drug release after internalisation of a conjugate.

  • Synthetic strategies in construction of organic macromolecular carrier–drug conjugates
    • Andrzej Skwarecki
    • Michał Nowak
    • Maria Milewska
    2020 ORGANIC & BIOMOLECULAR CHEMISTRY

    Many metabolic inhibitors, considered potential antimicrobial or anticancer drug candidates, exhibit verylimited ability to cross the biological membranes of target cells. The restricted cellular penetration ofthose molecules is often due to their highhydrophilicity. One of the possible solutions to this problem is aconjugation of an inhibitor with a molecular organic nanocarrier. The conjugate thus formed should beable to penetrate the membrane(s) by direct translocation, endocytosis or active transport mechanismsand once internalized, the active component could reach its intracellular target, either after release fromthe conjugate or in an intact form. Several such nanocarriers have been proposed so far, including macro-molecular systems, carbon nanotubes and dendrimers. Herein, we present a comprehensive review of thecurrent status of rational design and synthesis of macromolecular organic nanocarrier-drug conjugates,with special attention focused on the mode of coupling of a nanocarrier moiety with a“cargo”moleculethrough linking fragments of non-cleavable or cleavable type.

  • System architecture of an INSPIRE-compliant green cadastre system for the EU Member State of Poland
    • Agnieszka Dawidowicz
    • Marcin Kulawiak
    • Elżbieta Zysk
    • Katarzyna Kocur-Bera
    2020 Full text Remote Sensing Applications: Society and Environment

    In response to the need for a sustainable agricultural policy, which would support activities such as decision making in precise agriculture and mitigation of crop threats, a concept agricultural information system was developed for the area of Poland. This innovative concept, called Green Cadastre (GC), proposes to create a uniform system designed for use on a national scale by both state administration as well as local farmers. This article presents the concept system architecture of the proposed GC solution. The system architecture takes into account the current state of the INSPIRE Spatial Data Infrastructure, the previously established requirements for a GC system, as well as an analysis of current trends in geospatial IT. The proposed solution combines open data exchange protocols with Open Source technologies and current international SDI standards in order to provide a flexible and cost-effective solution.

  • System for monitoring road slippery based on CCTV cameras and convolutional neural networks
    • Dariusz Grabowski
    • Andrzej Czyżewski
    2020 Full text JOURNAL OF INTELLIGENT INFORMATION SYSTEMS

    The slipperiness of the surface is essential for road safety. The growing number of CCTV cameras opens the possibility of using them to automatically detect the slippery surface and inform road users about it. This paper presents a system of developed intelligent road signs, including a detector based on convolutional neural networks (CNNs) and the transferlearning method employed to the processing of images acquired with video cameras. Based on photos taken in different light conditions by CCTV cameras located at the roadsides in Poland, four network topologies have been trained and tested: Resnet50 v2, Resnet152 v2, Vgg19, and Densenet201. The last-mentioned network has proved to give the best result with 98.34% accuracy of classification dry, wet, and snowy roads.

  • System monitoringu rozdzielnic kampusu Politechniki Gdańskiej
    • Krzysztof Kwasigroch
    • Maciej Łukaszewicz
    • Ireneusz Mosoń
    2020 Full text Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    W artykule opisano koncepcję, realizację programową oraz stanowisko testowe systemu monitoringu rozdzielnic kampusu Politechniki Gdańskiej. Zaproponowano realizację sprzętową oraz opracowano realizację programową systemu monitoringu rozdzielnic dla dwóch budynków: Gmachu Głównego i Centrum Obsługi Technicznej. Ważną cechą opracowanego rozwiązania jest jego skalowalność, gdyż docelowo system monitoringu będzie obejmował wszystkie rozdzielnice kampusu Politechniki Gdańskiej. Do akwizycji sygnałów z aparatów elektrycznych przewidziano sterowniki programowalne easyE4, które będą zainstalowane w rozdzielnicach poszczególnych budynków. Funkcję nadrzędną w systemie monitoringu będzie pełnił sterownik programowalny XC-303. Jego zadaniem będzie zbieranie sygnałów ze wszystkich sterowników easyE4. Sterownik XC-303 będzie znajdował się w budynku Centrum obsługi Technicznej, oraz docelowo na serwerze w tym budynku zostanie zainstalowana opracowana wizualizacja. Wszystkie przewidziane w systemie monitoringu funkcje zostały uruchomione i przetestowane na zbudowanym w tym celu stanowisku testowym. Do programowania sterowników easyE4 wykorzystano środowisko programistyczne easySoft 7, a program na sterownik XC-303 opracowano w środowisku programistycznym CODESYS 3. Wizualizacja została opracowana w środowisku programistycznym Galileo 10. Do komunikacji pomiędzy urządzeniami systemu monitoringu wykorzystano protokół Modbus TCP. System monitoringu będzie wykorzystywał uczelnianą sieć komputerową Politechniki Gdańskiej.

  • Systematic review examining the evidence for impact of school policies on physical activity
    • Kevin Volf
    • Liam Kelly
    • Enrique García Bengoechea
    • Anna Gobis
    • Jeroen Lakerveld
    • Joanna Żukowska
    • Peter Gelius
    • Sven Messing
    • Sarah Forberger
    • Catherine Woods
    2020 EUROPEAN JOURNAL OF PUBLIC HEALTH

    Background Epidemiological evidence has demonstrated that physical activity can have substantive health benefits for children and young people. The 'Policy Evaluation Network' is a multi-disciplinary research network across 7 European countries and New Zealand aimed at building capacity and evaluating the level of impact of policy interventions for promoting healthy lifestyles. The Toronto Charter identified 'whole-of-school' programmes as one of seven key investments for promotion of PA. This paper presents results of a SLR, designed to assess the level of evidence for policies within the school setting that contribute directly or indirectly to increasing PA. Methods Researchers searched six online databases for scientific literature regarding PA policy interventions in the school setting using key concepts of policy, school, PA and evaluation. Risk of bias will be assessed with tools appropriate to the design of the studies considered. Evidence of actual or potential positive PA outcomes arising directly or indirectly from policy actions will be catalogued. Results Preliminary searches identified 2327 unique scientific articles. 1938 (83.3%) were excluded on first reading and 189 (8.8%) were included for full text analysis. Initial findings suggest that organisational policies, for example avoiding overcrowding in playgrounds during school breaks, may be a promising policy action. Detailed analysis revealing other potential policy actions supported by evidence will be presented (SLR in progress). Conclusions Preliminary findings suggest that few studies link policy actions in the school setting to PA outcomes. However, studies that have investigated the effects of changes to the school environment on PA levels may provide evidence for policy actions. Preliminary recommendations include strengthening the evidence base for school-based PA policy by supporting studies into the effects of particular policy or legislative changes on PA outcomes.

  • Systematic Water Uptake Energetics of Yttrium-Doped Barium Zirconate—A High Resolution Thermochemical Study
    • Mayra Goncalves
    • Aleksandra Mielewczyk-Gryń
    • Pardha Saradhi Maram
    • Łukasz Kryścio
    • Maria Gazda
    • Alexandra Navrotsky
    2020 Full text Journal of Physical Chemistry C

    A combination of surface area analyzer and microcalorimetry was employed to investigate the in situ water uptake energetics and the mechanism of proton incorporation in yttrium-doped barium zirconate in the temperature range 200–400 °C. The BaZr1–xYxO3 solid solutions are made with variable yttrium content (x = 10, 20, and 30 mol %) by a controlled oxidant-peroxo synthesis method. The water uptake increases as the partial pressure of water increases; however, no saturation in the hydration isotherm is observed, implying further reaction at higher pH2O. The results suggest three distinct regions of hydration energies as a function of water content. The first water uptake enthalpy values showed high exothermicity, −140, −158, and −157 kJ mol–1 for BaZr1–xYxO3 (x = 10, 20, and 30 mol %), respectively, at 400 °C, and the strong exothermic contribution supports the dissociative incorporation of water. The stepwise in situ hydration energetics is essential to understand the mechanisms of water incorporation and the role of H2O uptake in transport properties.

  • Systems engineering approach to functional safety and cyber security of industrial critical installations
    • Kazimierz Kosmowski
    2020 Full text

    This chapter addresses the systems engineering approach to integrated functional safety and cybersecurity analysis and management regarding selected references, standards and requirements concerning critical installations and their industrial automation and control system (IACS). The objective is to mitigate the vulnerability of industrial installations that include the information technology (IT) and the operational technology (OT) to reduce relevant risks. This approach includes verifying the safety integrity level (SIL) of defined safety functions, and then to check the level obtained taking into account the security assurance level (SAL) of particular domain, such as a safety related control system (SRCS), in which given safety function is to be implemented. The SAL is determined based on a vector of fundamental requirements (FRs). The method proposed uses defined risk graphs for the individual and/or the societal risk, and relevant risk criteria, for determining the SIL required of given safety function, and probabilistic models to verify the SIL achievable for the SRCS architecture to be designed and then implemented in an industrial installation.

  • Systems engineering approach to functional safety and cyber security of industrial critical installations
    • Kazimierz Kosmowski
    2020

    This chapter addresses the systems engineering approach to integrated functional safety and cybersecurity analysis and management regarding selected references, standards and requirements concerning critical installations and their industrial automation and control system (IACS). The objective is to mitigate the vulnerability of industrial installations that include the information technology (IT) and the operational technology (OT) to reduce relevant risks. This approach includes verifying the safety integrity level (SIL) of defined safety functions, and then to check the level obtained taking into account the security assurance level (SAL) of particular domain, such as a safety related control system (SRCS), in which given safety function is to be implemented. The SAL is determined based on a vector of fundamental requirements (FRs). The method proposed uses defined risk graphs for the individual and/or the societal risk, and relevant risk criteria, for determining the SIL required of given safety function, and probabilistic models to verify the SIL achievable for the SRCS architecture to be designed and then implemented in an industrial installation.

  • Szkodliwe związki powstające wskutek przemian sacharydów
    • Hanna Staroszczyk
    2020

    W rozdziale opisano zagadnienia związane ze zdrowotnymi aspektami spożywania sacharydów, scharakteryzowano alternatywne substancje słodzące oraz przedstawiono interakcje sacharydów z innymi składnikami żywności.

  • Świat i jego ekosystem mobilny – dane statystyczne i perspektywy rozwoju
    • Józef Woźniak
    2020

    Główną uwagę położono na szeroką prezentację technologii informacyjno-komunikacyjne, które, jak się powszechnie oczekuje, będą, podobnie jak w ostatnich dwóch dziesięcioleciach, istotnym elementem rozwoju i katalizatorem zmian zachodzących we wszystkich obszarach bazujących na wymianie, przetwarzaniu, przechowywaniu i udostępnianiu informacji cyfrowych, wpływając na rozwój i kreowanie różnorodnych ekosystemów cyfrowych. zaprezentowano sposoby wdrażania technologii piątej generacji (5G), wskazując fazy w implementacji i kamienie milowe w rozwoju systemów i sieci 5G w Polsce i na świecie. Uwagę poświęcono też koncepcjom IoT oraz nowym, perspektywicznym technologiom sieciowym. Zaprezentowano też szkicowo problemy odnoszące się do usług chmurowych.

  • Tangible and intangible economic impact of hosting mega sporting events
    • Krystian Zawadzki
    2020

    Due to the fact that the impetus for the creation of this paper was inaccuracies in the results of research relating to the economic effects caused by the organisation of mega sporting events, an analysis of the impact of 1988-2008 mega sporting events on host economies was conducted. The research shows that in selected areas of the economy, sporting events can be identified, with occasional positive (SOG) and negative (WOG) economic effects, both nationally and regionally.

  • Tax Evasion, Tax Morale, and Trade Regulations: Company-Level Evidence from Poland
    • Dagmara Nikulin
    2020 Full text Entrepreneurial Business and Economics Review

    Objective: To investigate the determinants of the phenomenon of evading taxes among polish entrepreneurs. In particular, I examine such factors as tax administration satisfaction, tax morale, tax burden, and the influence of trade regulations. Research Design & Methods: A survey study conducted in 2017 in Poland among 454 enterprises. I used the zero-inflated negative binomial modelling technique to examine the impact of factors on the probability and extent of tax evasion. I also checked the robustness of the obtained results. Findings: I report low tax morale of company managers, low level of satisfaction of tax administration, and tightness of trade regulations as important factors that impact the probability of tax evasion. Moreover, tax morale plays an important role in explaining the extent of underreporting income. I report no significant impact of tax burden on the probability to evade taxes and the magnitude of evasion. Implications & Recommendations: Tax burden should not be considered as predominant in explaining tax evasion inclinations. More social aspects, like the perceived quality of governance, the level of trade regulations, and tax morale, become increasingly important in affecting tax evasion attitudes. Contribution & Value Added: I offer empirical evidence on the determinants of tax evasion. To that end, I utilise a new econometric approach and own primary data.

  • Taxonomy of Schemes for Resilient Routing
    • Ivan Ganchev
    • Jacek Rak
    • Tibor Cinkler
    • Máirtín O’droma
    2020

    This chapter provides a taxonomy of schemes for resilient routing followed by a discussion of their application to contemporary architectures of communication networks. In particular, a general classification of schemes for resilient routing is first presented followed by a description of the reference schemes for IP networks. The chapter in its later part focuses on the representative techniques of resilient routing for a multi-domain and multi-layer network scenarios followed by conclusions also referring to the applicability of the resilient routing schemes in disaster scenarios.

  • Teaching architectural history through virtual reality
    • Szymon Kowalski
    • Piotr Samól
    • Jakub Szczepański
    • Witold Dłubakowski
    2020 Full text World Transactions on Engineering and Technology Education

    The impact of implementing 3D models and virtual reality in teaching the theory of architecture and architectural history is the theme of this article. Virtual reality and easy-to-use 3D tools allow a whole historic object to be visualised. As a result, there is social and economic pressure to modernise present educational methods using this technology. Therefore, the authors have focused their research on an issue of significance today: how the newest digital technologies might influence the development of students’ technical skills and their abilities for logical thinking.

  • Team Roles and Team Performance in Small Virtual Software Teams
    • Beata Krawczyk-Bryłka
    2020 ZARZĄDZANIE ZASOBAMI LUDZKIMI

    The article presents the results of research on the composition of team roles conducted in 24 student software teams. An adaptation of M. Belbin’s model by B. Kożusznik was used. The model of team balance according to Belbin and Haaf is presented and correlations between team balance and team performance are analysed. Team performance is measured at three levels: result, satisfaction and team climate. The selected constellation of team roles (such as Shaper and Plant, Implementer and Monitor-Evaluator) were analysed in the context of software team performance. The level of team virtualisation was also taken into account.

  • Technical and Economic Analysis of the Implementation of Selected Variants of Road Investment
    • Marcin Szczepański
    • Beata Grzyl
    2020 Full text Buildings

    The aim of the article is to analyze three variants of modernization and reconstruction of a road intersection, which in practice is the cause of numerous collisions and accidents. Detailed design solutions are presented for them. The aim of the analyses is to indicate an effective solution that, taking into account technical modifications of the road system elements, will ensure the functionality of the road system to the highest degree and significantly reduce the number of road incidents. To indicate the optimal solution, quantitative data (cost and duration of activities for three options) and qualitative data (determined based on the own experience and knowledge of road industry experts) is analyzed. The authors refer to many criteria of various natures (e.g., economic, technical, functional, environmental, social), which allow for comprehensive consideration of the current requirements of road users and changing circumstances, among others a steady increase in the number of vehicles and growing social expectations in terms of road parameters. Considering the presented analyses and arguments, the authors recommend option 1 as optimal. This is the most expensive solution among those analyzed and with the longest implementation time, however, taking into account the long-term prognosis of the direction and scope of changes to the existing standards and requirements for road infrastructure, it can be stated that option 1 meets them to the highest degree, and also has the greatest potential. The envisaged solution ensures high standards of the quality of road infrastructure use in terms of functionality, capacity, technical parameters, as well as the safety of traffic participants related to the smoothness of the journey, reduction of the number of collisions and accidents.

  • Techno‐economic evaluation of a natural deep eutectic solvent‐based biorefinery: Exploring different design scenarios
    • Adepu K. Kumar
    • Shaishav Sharma
    • Gaurav Dixit
    • Ekta Shah
    • Aesha Patel
    • Grzegorz Boczkaj
    2020 Biofuels Bioproducts & Biorefining-Biofpr

    This paper presents a comprehensive techno‐economic evaluation of an integrated natural deep eutectic solvent (NADES)‐based biorefinery – a 1 ton day−1 capacity design plant. The key parameters include payback period, net present value (NPV), and internal rate of return (IRR). These were compared with the parameters of conventional biorefineries. The ‘n th plant’ results clearly revealed that the single product‐based biorefinery is not a sustainable approach. Hence, value‐added products viz ., cellulose, lignin, xylan, silica, etc ., play a vital role in the cost‐effectiveness of bio‐based biorefineries. Based on ‘base‐case’ experimental results, a pilot‐scale plant design scenario is most feasible, with a NPV of 1.4 million USD, >100% IRR, and a payback period of <2 years. Sensitivity analysis revealed that lignin has the greatest impact on revenue. This report proves that multi‐product biorefineries provide better sustainability. The concepts of solvent recycling and reuse, and key challenges to the commercialization of this design approach, were also discussed. The application of NADES in biorefineries, has several advantages, making the implementation of NADES a key feature for increased sustainability in this industry.

  • Technologia wytwarzania opakowań PET dla produktów wrażliwych
    • Waldemar Karaszewski
    2020 Żródło. Wody i napoje butelkowane

    W artykule przedstawiono nowoczesne, liniowe maszyny rozdmuchowe przeznaczone do wytwarzania opakowań (butelek) PET metodą rozdmuchu z preform. Opisano systemy umożliwiające zmniejszenie zużycia energii elektrycznej niezbędnej do wytworzenia jednego opakowania PET.

  • Technological and Media Platforms: Redefinition of Meanings as Symbolic Power over the Discourse
    • Jan Kreft
    2020 Full text

    Redefining the meanings of such social terms as “likes” and “friends” on Facebook is a popular practice. In terms of consistency, the (auto)-redefinition of the term “platform” is itself particularly important from a media management perspective. The article proposes to consider the redefinition of meanings as a form of wielding non-transparent power over discourse. From this perspective, redefining a meaning is a form of holding symbolic power, i.e. imposing meaning and thus concealing the system of powers existing at its base. The article is theoretical in its nature and complements the framework that explains how, by redefining and imposing new meanings, media and technology platform managing companies can use a new interpretation of the relationship between the organization and the user and other entities. The aim of the article is to stimulate research on the redefinition of meanings as a form of media management by providing a new theoretical perspective. Hermeneutics, that provides a framework for looking at the redefinition of meanings, was taken as the theoretical perspective.

  • Technological capability dynamics through cluster organizations
    • Anna Lis
    • Małgorzata Rozkwitalska
    2020 Full text Baltic Journal of Management

    Purpose – The purpose of the paper is to portrait how members of cluster organizations (COs) perceive the role of COs in enabling them to accumulate technological capability (TC) significant for their innovation. Design/methodology/approach – The authors report the findings from their qualitative study based on an analysis of four COs. The organizational inertia and absorptive capacity (AC) theories are the theoretical underpinning of the research. Findings – The study shows that the dynamics of TC of the cluster companies included in the study sample relates to their initial level of TC and cluster cooperation. The companies with relatively low initial TC increase it through COs if the clusters offer comparatively high benefits. On the other hand, those COs’ members that present relatively high initial TC advance it, provided that the external knowledge and other benefits they can absorb in their clusters are suited to their technological trajectories. Research implications/limitations – The research is preliminary in nature and portrays how firms with different levels of TC cooperate within COs and how this cooperation translates into TC improvements. The findings add to the state-of-the-art knowledge on the link between TC and AC of companies involved in COs by depicting the role of COs in providing knowledge and other cluster benefits that help cluster companies to accumulate TC and improve their AC. Nevertheless, the applied methodology does not allow the authors to generalize the findings. Practical implications – The coordinators of COs should skillfully shape the levels of cluster cooperation, matching them to the desired level of the cluster companies. They should create smaller subgroups composed of companies with similar TC, which may translate into its higher dynamics. Originality/value – The knowledge about the role of COs in providing cluster benefits that help cluster companies to accumulate TC and improve their AC is still insufficient. The study shed new light on the key role of the levels of cluster cooperation and the types of commitment related to them (i.e. technological effort), which may be a matter of importance in the dynamics of TC accumulation.

  • Tecnología y Democracia ¿Un amor de pandemia o una relación estable?
    • Robert Krimmer
    • David Duenas Cid
    2020

    Prologar una obra como esta es un privilegio y una responsabilidad. Es un privilegio en tanto que da paso a un seguido de contribuciones de gran calado y relevancia académica que contribuyen a la mejora del conocimiento existente acerca de la relación entre la tecnología y el funcionamiento de la democracia. Es una responsabilidad en el sentido que debe poner sobre la mesa algunas de las cuestiones abiertas de la disciplina y como se engarzan con la motivación que reside detrás de esta propuesta editorial, en un momento en que es más necesaria que nunca. Sabiendo de la complejidad de este cometido, queremos arrojar algunas ideas que sirvan para enmarcar la relación que existe entre los dos conceptos en liza en: tecnología, democracia y su (a nuestro entender, necesaria) interrelación.

  • Telomere uncapping by common oxidative guanine lesions: Insights from atomistic models
    • Miłosz Wieczór
    • Jacek Czub
    2020 FREE RADICAL BIOLOGY AND MEDICINE

    Oxidative damage to DNA is widely known to contribute to aging and disease. This relationship has been extensively studied for telomeres – structures that cap chromosome ends – due to their role in cell proliferation and senescence, and exceptional susceptibility to oxidation. Indeed, the repetitive telomeric DNA sequence contains the 5′-GGG-3′ motif that has the lowest ionization potential of all trinucleotides. Accordingly, experiments consistently show that telomeric oxidative lesions are more abundant and persistent than elsewhere in the genome. This led to a hypothesis that telomeres act as sensors of prolonged oxidative stress and prevent carcinogenesis, as disruption of telomeric integrity triggers senescence or apoptosis. Here, we use atomistic alchemical Molecular Dynamics simulations to perform a combinatorial assessment of changes in DNA binding affinity of telomeric proteins induced by oxidative guanine lesions. We rank lesions by their effect on telomere integrity, as well as telomeric proteins by their sensitivity to DNA oxidation. While the binding of most proteins is abolished by DNA oxidation, HOT1 emerges as a notable exception, suggesting its potential role in sensing of oxidative damage. Through statistical analysis and free energy decomposition, we also identify common trends in structural responses of protein-DNA complexes that contribute to decreased binding affinity.

  • Temperature distribution of supercapacitors prepared by various technologies
    • Stanisław Galla
    • Arkadiusz Szewczyk
    • Janusz Smulko
    • Łukasz Lentka
    2020 Full text Materials Today: Proceedings

    Supercapacitors, also known by different names such as electrostatic double-layer capacitors (EDLCs) or ultra-capacitors, are electrical storage devices still in development. These devices require fast and reliable methods of assessing their state-of-health. Thermographic imaging is a method which can be applied with this aim due to its popularity, and the high negative impact of overheating on a supercapacitor’s parameters. Moreover, thermographic imaging can be easily used to identify any hot spots, present during charging and discharging while in use. These devices are comprised of porous carbon electrodes and an electrolyte, and during the charging/discharging process, extensive heat may be generated and dissipated there. We have observed temperature fluctuations and were able to identify the inhomogeneity of the tested structures. The electrical parameters (capacitance C and equivalent serial resistance ESR) were measured to determine deterioration of the specimen as requested by the industrial standard. X-ray examination of the samples was performed to identify the shape of the applied metal charge collectors. Both techniques indicated areas where eventual overheating took place due to their electrodes’ shape, suggesting their further optimisation. The proposed method is much less accurate than the calorimetric methods, determining energy flows, but is still sufficient to identify problems with heat dissipation in the developed specimens. Finally, some conclusions about the ability to apply this method in practice to monitor supercapacitors during use were presented.

  • Termoplastyczne elastomery poli(estro-uretanowe) otrzymywane z udziałem bio-glikolu poddane dwukrotnemu przetwórstwu
    • Ewa Głowińska
    • Joanna Niesiobędzka
    • Arkadiusz Cybart
    • Janusz Datta
    2020 Full text Elastomery

    Recykling materiałów polimerowych w istotny sposób wpływa na zmniejszenie ilości odpadów z tworzyw sztucznych składowanych na wysypiskach śmieci. Jedną z metod recyklingu jest recykling mechaniczny, stosowany szczególnie w przypadku materiałów o właściwościach termoplastycznych. W pracy zbadano wpływ dwukrotnego przetwórstwa termoplastycznych elastomerów poli(estro-uretanowych), TPU, otrzymywanych z udziałem bio-glikolu na strukturę chemiczną, właściwości termiczne, przetwórcze i mechaniczne. W efekcie umożliwi to prognozowanie ilości cykli przetwórczych oraz określenie zmian, jakie mogą zajść w strukturze i właściwościach. Poli(estro-uretany) otrzymano metodą prepolimerową. Zsyntezowane materiały po uprzednim rozdrobnieniu poddano dwukrotnie procesom przetwórczym za pomocą mieszalnika typu Brabender. Próbki do badań formowano przy użyciu prasy hydraulicznej. Strukturę chemiczną otrzymanych materiałów określono za pomocą spektroskopii w podczerwieni FTIR. Zbadano wskaźnik szybkości płynięcia (MFI), właściwości termiczne i mechaniczne, twardość oraz gęstość. Na podstawie przeprowadzonych badań wykazano wpływ ponownego przetwórstwa na zmiany w strukturze oraz badanych właściwościach poli(estro-uretanów). Stwierdzono, że otrzymane materiały mogą być ponownie wykorzystane do produkcji nowych wyrobów, niemniej jednak zmianie ulegną ich warunki przetwórcze. Słowa kluczowe: termoplastyczne elastomery poli(estro-uretanowe), wskaźnik szybkości płynięcia, właściwości mechaniczne, właściwości termiczne, przetwórstwo.

  • Test Stand for Multi-option Stretching of Soft Tissues
    • Grzegorz Rotta
    • Szymon Grymek
    2020

    The paper presents the genesis of the design and possibilities of the test stand for stretching soft tissues as well as examples of tests carried out on this device.

  • Test Stand for Multi-option Stretching of Soft Tissues
    • Grzegorz Rotta
    • Szymon Grymek
    2020

    The paper presents the genesis of the design and possibilities of the test stand for stretching soft tissues as well as examples of tests carried out on this device.

  • Testing sensitivity of A-type residual current devices to earth fault currents with harmonics
    • Stanisław Czapp
    2020 Full text SENSORS

    In many applications, modern current-using equipment utilizes power electronic converters to control the consumed power and to adjust the motor speed. Such equipment is used both in industrial and domestic installations. A characteristic feature of the converters is producing distorted earth fault currents, which contain a wide spectrum of harmonics, including high-order harmonics. Nowadays, protection against electric shock in low-voltage power systems is commonly performed with the use of residual current devices (RCDs). In the presence of harmonics, the RCDs may have a tripping current significantly different from that provided for the nominal sinusoidal waveform. Thus, in some cases, protection against electric shock may not be effective. The aim of this paper is to present the result of a wide-range laboratory test of the sensitivity of A-type RCDs in the presence of harmonics. This test has shown that the behavior of RCDs in the presence of harmonics can be varied, including the cases in which the RCD does not react to the distorted earth fault current, as well as cases in which the sensitivity of the RCD is increased. The properties of the main elements of RCDs, including the current sensor, for high-frequency current components are discussed as well.

  • Testing Stability of Digital Filters Using Multimodal Particle Swarm Optimization with Phase Analysis
    • Damian Trofimowicz
    • Tomasz Stefański
    2020

    In this paper, a novel meta-heuristic method for evaluation of digital filter stability is presented. The proposed method is very general because it allows one to evaluate stability of systems whose characteristic equations are not based on polynomials. The method combines an efficient evolutionary algorithm represented by the particle swarm optimization and the phase analysis of a complex function in the characteristic equation. The method generates randomly distributed particles (i.e., a swarm) within the unit circle on the complex plane and extracts the phase quadrant of function value in position of each particle. By determining the function phase quadrants, regions of immediate vicinity of unstable zeros, called candidate regions, are detected. In these regions, both real and imaginary parts of the complex function change signs. Then, the candidate regions are explored by subsequently generated swarms. When sizes of the candidate regions are reduced to a value of assumed accuracy, then the occurrence of unstable zero is verified with the use of discrete Cauchy's argument principle. The algorithm is evaluated in four benchmarks for integer- and fractional-order digital filters and systems. The numerical results show that the algorithm is able to evaluate the stability of digital filters very fast even with a small number of particles in subsequent swarms. However, the multimodal particle swarm optimization with phase analysis may not be computationally efficient in stability tests of systems with complicated phase portraits.

  • Testing the Positioning Accuracy of GNSS Solutions during the Tramway Track Mobile Satellite Measurements in Diverse Urban Signal Reception Conditions
    • Mariusz Specht
    • Cezary Specht
    • Andrzej Wilk
    • Władysław Koc
    • Leszek Smolarek
    • Krzysztof Czaplewski
    • Krzysztof Karwowski
    • Paweł S. Dąbrowski
    • Jacek Skibicki
    • Piotr Chrostowski
    • Jacek Szmagliński
    • Sławomir Grulkowski
    • Sławomir Judek
    2020 Full text ENERGIES

    Mobile Global Navigation Satellite System (GNSS) measurements carried out on the railway consist of using satellite navigation systems to determine the track geometry of a moving railway vehicle on a given route. Their purposes include diagnostics, stocktaking, and design work in railways. The greatest advantage of this method is the ability to perform measurements in a unified and coherent spatial reference system, which effectively enables the combining of design and construction works, as well as their implementation by engineering teams of diverse specialties. In the article, we attempted to assess the impact of using three types of work mode for a GNSS geodetic network [Global Positioning System (GPS), GPS/Global Navigation Satellite System (GLONASS) and GPS/GLONASS/Galileo] on positioning availability at three accuracy levels: 1 cm, 3 cm and 10 cm. This paper presents a mathematical model that enables the calculation of positioning availability at these levels. This model was also applied to the results of the measurement campaign performed by five GNSS geodetic receivers, made by a leading company in the field. Measurements with simultaneous position recording and accuracy assessment were taken separately on the same route for three types of receiver settings: GPS, GPS/GLONASS and GPS/GLONASS/Galileo in an urban area typical of a medium-sized city. The study has shown that applying a two-system solution (GPS/GLONASS) considerably increases the availability of high-precision coordinates compared to a single-system solution (GPS), whereas the measurements with three systems (GPS/GLONASS/Galileo) negligibly increase the availability compared to a two-system solution (GPS/GLONASS).

  • Tests of bond between concrete and steel bars – literature background and program of own research
    • Marcin Burdziński
    • Maciej Niedostatkiewicz
    • Patryk Ziółkowski
    2020 Full text Budownictwo i Architektura

    This article deals with the issue of the bond between concrete and reinforcement. The bond is crucial for reinforced concrete elements because it is possible to transfer forces (stresses) from concrete to the reinforcement. Basic information related to the cooperation of concrete and rebars was recalled in the article. Selected issues concerning theoretical and numerical analysis as well as experiments of the bond phenomenon were presented. The article also proposes its own concept of experimental studies on the bond on two types of specimens: so-called short specimen and large specimen that will be subjected to pull-out tests. The described concept is ultimately to form the basis for creating a numerical model, enabling the simulation of bond in various reinforced concrete elements, calibrated based on the results of experimental studies.

  • Texture Features for the Detection of Playback Attacks: Towards a Robust Solution
    • Maciej Smiatacz
    2020 Advances in Intelligent Systems and Computing

    This paper describes the new version of a method that is capable of protecting automatic speaker verification (ASV) systems from playback attacks. The presented approach uses computer vision techniques, such as the texture feature extraction based on Local Ternary Patterns (LTP), to identify spoofed recordings. Our goal is to make the algorithm independent from the contents of the training set as much as possible; we look for the descriptors that would allow the method to detect attacks performed in an environment entirely different from the training one and with the use of the equipment that differs considerably from the devices that captured the training samples. The final form of our method, based on the previously presented proof of concept, performs significantly better than the reference Textrogram algorithm.

  • The abrasive wear resistance of coatings manufactured on high-strength low-alloy (HSLA) offshore steel in wet welding conditions
    • Jacek Tomków
    • Artur Czupryński
    • Dariusz Fydrych
    2020 Full text Coatings

    Some marine and offshore structure elements exploited in the water cannot be brought to the surface of the water as this will generate high costs, and for this reason, they require in-situ repairs. One of the repair techniques used in underwater pad welding conditions is a wet welding method. This paper presents an investigation of the abrasive wear resistance of coatings made in wet welding conditions with the use of two grades of covered electrodes—an electrode for underwater welding and a commercial general use electrode. Both electrodes were also used for manufacturing coatings in the air, which has been also tested. The Vickers HV10 hardness measurements are performed to demonstrate the correlation in abrasive wear resistance and the hardness of each specimen. The microscopic testing was performed. For both filler materials, the coatings prepared in a water environment are characterized by higher resistance to metal–mineral abrasion than coatings prepared in an air environment—0.61 vs. 0.44 for commercial usage electrode and 0.67 vs. 0.60 for underwater welding. We also proved that in the water, the abrasive wear was greater for specimens welded by the general use electrode, which results in a higher hardness of the layer surface. In the air welding conditions, the layer welded by the electrode for use in the water was characterized by a lower hardness and higher resistance to metal–mineral abrasion. The microstructure of the prepared layers is different for both the environment and both electrodes, which results in abrasive wear resistance.

  • The Analysis of Working Parameters Decrease in Photovoltaic Modules as a Result of Dust Deposition
    • Ewa Klugmann-Radziemska
    • Małgorzata Rudnicka
    2020 Full text ENERGIES

    The aspect of dust accumulation on the surface of photovoltaic (PV) modules should be thoroughly understood in order to minimize possible obstacles affecting energy generation. Several elements affect the amount of pollutant gathered on the surface of a solar device, mainly its localization, which is irreversibly linked to factors such as annual rainfall, occasional snow coverage, or, in a dry climate, increased blow of dust during sandstorms and higher concentration of soil particles in desert areas. Other than weather conditions in the region, PV installation type also plays an important role as a more horizontal position is favorable for the accumulation of soil. The research carried out and presented in this paper was done for dust accumulated naturally on PV modules kept in outdoor conditions and dust artificially sieved onto the front glass cover of modules. The experiment performed by the authors, including artificially deposited dust, defined the linear relationship between surface dust density of different types of contaminants and efficiency decline up to 10% for two different PV modules. The additional field study carried out in external conditions for a coastal region in Northern Poland concluded that, after one year, exposition photovoltaic conversion efficiency can be over 10% lower, with a slight performance improvement for the autumn season characterized by heavy rainfall.

  • THE APPLICATION OF THE MECHANOCHEMICAL SYNTHESIS FOR THE PREPARATION OF ADVANCED CERAMICS BASED ON BARIUM TITANATE
    • Barbara Garbarz-Glos
    • Wojciech Bąk
    • Andrzej Budziak
    • Piotr Dulian
    • Agata Lisińska-Czekaj
    • Dionizy Czekaj
    2020 Full text ARCHIVES OF METALLURGY AND MATERIALS

    In the present study, the lead-free BaTi1-xZrxO3 (for x = 0, 0.05 and 0.15) ceramics were prepared by High-Energy Ball Milling and heat treatments. The performed X-ray, SEM and EDS measurements confirmed high purity, good quality and the expected quantitative composition of the obtained samples. The study of dielectric properties was performed by means of broadband dielectric spectroscopy at the frequency ranging from 0.1 Hz to 10 MHz. The obtained measurement data, analyzed in accordance with the Arrhenius formalism demonstrated the presence of relaxation type dielectric mechanisms. The impedance answer of studied ceramic materials indicated the presence of two relaxation processes: one with a dominant resistive component and the other with a small capacitive component. The observed dielectric relaxation process is temperature dependent and has a “non-Debye” character.

  • The application of the Superpave method of climatic zones analysis in Poland with regard to bitumen performance grading
    • Marek Pszczoła
    • Dawid Ryś
    • Piotr Jaskuła
    2020

    Currently in Poland, similarly as in the other EU countries, road bitumens are tested and classified with regard to mainly the penetration value determined at the tempera-ture of 25C. It should be noted that this classification is not correlated with the cli-matic conditions in which the bitumens are to serve in the road pavement. Towards the end of the last century a new system of bitumen grading was developed and im-plemented as part of the American Strategic Highway Research Program (SHRP). This paper presents the results of analyses concerning the determination of the tempera-tures at which bituminous binders serve in the Polish climatic conditions. A division of the area of Poland into climatic zones depending on the required performance grades (PGs) determined for bitumens on the basis of climatic data from meteorological sta-tions for a period of minimum 20 years is presented. It is proposed to select bitumens depending on the climatic zone in Poland, taking into account the proper probability level which follows from the road class.

  • The behavioural model of graphene field-effect transistor
    • Maciej Łuszczek
    • Marek Turzyński
    • Dariusz Świsulski
    2020 Full text International Journal of Electronics and Telecommunications

    The behavioural model of a graphene field-effect transistor (GFET) is proposed. In this approach the GFET element is treated as a “black box” with only external terminals available and without considering the physical phenomena directly. The presented circuit model was constructed to reflect steady-states characteristics taking also into account GFET capacitances. The authors’ model is defined by a relatively small number of equations which are not nested and all the parameters can be easily extracted. It was demonstrated that the proposed model allows to simulate the steady-state characteristics with the accuracy approximately as high as in the case of the physical model. The presented compact GFET model can be used for circuit or system-level simulations in the future.

  • The CDIO model in architectural education and research by design
    • Lucyna Nyka
    • Jan Cudzik
    • Katarzyna Urbanowicz
    2020 Full text World Transactions on Engineering and Technology Education

    Architectural education has always been related to experimentation: that is, defining concepts, drawing sketches, working on models, then testing and modifying them. This activity mirrors the CDIO learning methods and objectives. Despite this, research studies into the applicability of the CDIO model in architectural curricula are scarce. In the discipline of architecture, hands-on experiences are associated not only with one of the most effective methods of education, but also with a particular way of carrying out research, that is research by design. In this article, the authors present the integration of the CDIO framework into the architectural engineering curricula at Gdańsk University of Technology, Gdańsk, Poland, discuss the results, and indicate which components of architectural education have benefited most from this integration. Another objective was to initiate a discussion on the potential impacts of implementing CDIO into architectural curricula, and its relation to the research by design concept.

  • The correlation between the MRI-evaluated ectopic fat accumulation and the incidence of diabetes mellitus and hypertension depends on body mass index and waist circumference ratio.
    • Mariusz Kaszubowski
    • J Pieńkowska
    • B. Brzeska
    • O. Kozak
    • A. Jankowska
    • Edyta Szurowska
    2020 Full text PLOS ONE

    The widespread presence of overweight and obesity increases with every decade, and the number of people with body mass index (BMI) >30 kg/m2 has doubled in the last 30 years. The aim of the study is to assess the correlation between MRI-evaluated ectopic fat accumulation in pancreas, skeletal muscles and liver and the incidence of type 2 diabetes and hypertension, depending on BMI and waist circumference ratio. This prospective study included 267 consecutive patients who were referred to abdominal MRI and underwent a standard clinical assessment with BMI and waist circumference ratio calculation. Ectopic fat accumulation in pancreas, skeletal muscles and liver was evaluated in magnetic resonance imaging using the fat-water separated Dixon imaging. There were statistically significant differences in mean steatosis of all assessed organs in the group of patients with type 2 diabetes or hypertension in comparison to the non-diabetic group as well as to the group without hypertension. It has been observed that pancreas and skeletal muscles are more susceptible to fat accumulation than liver. According to our results, there is a relation between the fat content in muscles, pancreas and liver, the incidence of type 2 diabetes and hypertension and also body mass index and waist circumference ratio. We believe that future studies should aim to determine whether the use of fat content measurement in certain organs could be used as a biomarker that can enable early detection of reversible metabolic changes, as well as their subsequent monitoring.

  • The Design Development of the Sliding Table Saw Towards Improving Its Dynamic Properties
    • Kazimierz Orłowski
    • Przemysław Dudek
    • Daniel Chuchała
    • Wojciech Blacharski
    • Tomasz Przybyliński
    2020 Full text Applied Sciences-Basel

    Cutting wood with circular saws is a popular machining operation in the woodworking and furniture industries. In the latter sliding table saws (panel saws) are commonly used for cutting of medium density fiberboards (MDF), high density fiberboards (HDF), laminate veneer lumber (LVL), plywood and chipboards of different structures. The most demanded requirements for machine tools are accuracy and precision, which mainly depend on the static deformation and dynamic behavior of the machine tool under variable cutting forces. The aim of this study is to present a new holistic approach in the process of changing the sliding table saw design solutions in order to obtain a better machine tool that can compete in the contemporary machine tool market. This study presents design variants of saw spindles, the changes that increase the critical speeds of spindles, the measurement results of the dynamic properties of the main drive system, as well as the development of the machine body structure. It was proved that the use of only rational imitation in the spindle design on the basis of the other sliding table saws produced does not lead to the expected effect in the form of correct spindle operation.

  • The dispersive micro-solid phase extraction method for MS-based lipidomics of human breast milk*
    • Inal Bakhytkyzy
    • Weronika Hewelt-Belka
    • Agata Kot-Wasik
    2020 Full text MICROCHEMICAL JOURNAL

    A simple and rapid microextraction method ensuring high lipidome coverage was developed for liquid chromatography mass spectrometry (LC-MS)-based lipidomics of human breast milk. The dispersive microsolid phase extraction (D-µ-SPE) technique, coupled with the design of experiment (DoE) method, enabled the study of the influence of several conditions (desorption solvent, stationary phase ratio, and sorption and desorption time) on the lipid extraction process of various lipid classes. The D-µ-SPE-based method, which used a mixture of C18 and zirconia-coated silica gel as the sorbent, allowed for the extraction of a wide range lipid classes characterized by different concentration levels. The developed method simplified the extraction procedure for lipidomics without loss of good reproducibility (70% of the MFs had peak volume %RSD <20% for all the tested stationary phases). The highest lipidome coverage was achieved when 100 µL of the human breast milk (HBM) sample was extracted using 27 mg of C18 mixed with 3 mg of zirconia-coated silica gel as the sorbent and methanol:2-propanol: ammonium hydroxide (14:81:5 v/v/v) mixture as the desorption solvent. The sorption and desorption time did not influence the number of extracted molecular features. The advantages of the present method over the traditional SPE and liquid-liquid extraction (LLE) commonly used in lipidomics are the possibility of mixing sorbents with various sorption mechanisms, which ensures high lipidome coverage, and the use of a small number of materials, including the sorbent and organic solvent.

  • The dynamic signature verification using population-based vertical partitioning
    • Marcin Zalasiński
    • Krzysztof Cpałka
    • Tacjana Niksa-Rynkiewicz
    2020

    The dynamic signature is an attribute used in behavioral biometrics for verifying the identity of an individual. This attribute, apart from the shape of the signature, also contains information about the dynamics of the signing process described by the signals which tend to change over time. It is possible to process those signals in order to obtain descriptors of the signature characteristic of an individual user. One of the methods used in order to determine such descriptors is based on signals partitioning. In this paper, we propose a new method using a population-based algorithm for determining vertical partitions of the signature and its descriptors. Our method uses a Differential Evolution algorithm for signals partitioning and an authorial one-class fuzzy classifier for verifying the effectiveness of this process. In the simulations, we use a commercial BioSecure DS2 dynamic signature database.

  • The effect of Ag, Au, Pt, and Pd on the surface properties, photocatalytic activity and toxicity of multicomponent TiO2-based nanomaterials
    • Anna Malankowska
    • Alicja Mikołajczyk
    • Joanna Mędrzycka
    • Izabela Wysocka
    • Grzegorz Nowaczyk
    • Marcin Jarek
    • Tomasz Puzyn
    • Ewa Mulkiewicz
    2020 Environmental Science-Nano

    Multicomponent TiO2-based nanomaterials (MC-NMs) show better physicochemical properties than their individual components or bulk materials. However, the same unique properties that offer innovative applications might also pose unknown risks to human health and the environment. In this context, TiO2- based nanomaterials with a mixture of noble metal precursors (Ag, Au, Pt, and Pd) for large-scale technological applications in air purification were designed, synthesized and characterized. The influence of the type and amount of noble metal precursor on the optical properties and photocatalytic activity of MC-NMs and their toxicity to mouse embryo fibroblast cell line (BALB/3T3), human lung cell line (A549) and human liver cell line (HepG2) was investigated. A hazard assessment of the designed TiO2-based MCNMs was performed for the first time according to the standards developed under the Joint Research Center and NANoReg2 project (Horizon 2020). The threshold concentration of monometallic NPs that ensure high photocatalytic activity without increasing hazard to humans and the environment was determined. The results indicated that the most effective sample is represented by the 0.1Ag_0.1Au_0.1Pt_1Pd/TiO2 photocatalyst, in which noble metal NPs demonstrated a synergistic effect on photocatalytic activity without increasing the toxicity (safe MC-NMs with 86% toluene degradation after 1 h of irradiation, efficiency 5 times higher than that of pristine TiO2). The obtained results confirm that systematic knowledge and proper manipulation of component concentration may lead to rational design of safe TiO2-based MC-NMs with wide application in air purification under solar energy.

  • The Effect of AgInS2, SnS, CuS2, Bi2S3 Quantum Dots on the Surface Properties and Photocatalytic Activity of QDs-Sensitized TiO2 Composite
    • Anna Malankowska
    • Daria Kulesza
    • Jakub Sowik
    • Onur Cavdar
    • Tomasz Klimczuk
    • Grzegorz Trykowski
    • Adriana Zaleska-Medynska
    2020 Full text Catalysts

    The eect of type (AgInS2, SnS, CuS2, Bi2S3) and amount (5, 10, 15 wt%) of quantum dots (QDs) on the surface properties and photocatalytic activity of QDs-sensitized TiO2 composite, was investigated. AgInS2, SnS, CuS2, Bi2S3 QDs were obtained by hot-injection, sonochemical, microwave, and hot-injection method, respectively. To characterize of as-prepared samples high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diraction (XRD), UV-Vis spectroscopy and photoluminescence (PL) emission spectroscopy were applied. The size of AgInS2, SnS, CuS2, Bi2S3 QDs were 12; 2–6; 2–3, and 1–2 nm, respectively. The QDs and QDs-sensitized TiO2 composites obtained have been tested in toluene degradation under LEDs light irradiation (max = 415 nm and max = 375 nm). For pristine QDs the eciency of toluene degradation increased in the order of AgInS2 < Bi2S3 < CuS < SnS under 375 nm and AgInS2 < CuS < Bi2S3 < SnS under 415 nm. In the presence of TiO2/SnS QDs_15% composite, 91% of toluene was degraded after 1 h of irradiation, and this eciency was about 12 higher than that for pristine QDs under 375 nm. Generally, building the TiO2/AgInS2 and TiO2/SnS exhibited higher photoactivity under 375 nm than the pristine TiO2 and QDs which suggests a synergistic eect between QDs and TiO2 matrix.