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Gdańsk University of Technology

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  • Effect of selected ammonia escape inhibitors on carbon dioxide capture and utilization via calcium carbonate precipitation
    • Natalia Czaplicka
    • Donata Konopacka-Łyskawa
    • Barbara Kościelska
    • Marcin Łapiński
    2020 Journal of CO2 Utilization

    Carbon dioxide was used to precipitate CaCO3 with CaCl2 solution in the presence of NH3 as a CO2 absorption promoter. Compounds that were previously indicated as inhibitors of ammonia escape during CO2 absorption were also added to the reaction mixture. Inorganic salts, i.e. ZnCl2, CuCl2, CoCl2, and organic substances, i.e. glycerol, ethylene glycol and triethanolamine were tested inhibitors in this work. A model post-distillation liquid from the Solvay process was used as the reaction mixture, while the gas stream fed into the system had a composition corresponding to the exhausted gases produced by the fossil fuels combustion. The purpose of this research was to investigate the efficiency of CO2 sequestration and the consumption of calcium ions during precipitation in the carbonation processes and determine the characteristics of produced CaCO3 particles. Of the tested additives, glycerol turned out to be the most effective, because its presence resulted in increased calcium ion consumption and CO2 sequestration compared to the control process. 90.5 % CO2 sequestration and 88.1 % Ca2+ consumption were obtained. The CaCO3 particles obtained in the presence of all tested organic inhibitors were in the form of vaterite and were characterized by a significantly larger specific surface area and larger pore volume.

  • Effect of sintering temperature on electrochemical performance of porous SrTi1-xFexO3-δ (x = 0.35, 0.5, 0.7) oxygen electrodes for solid oxide cells
    • Aleksander Mroziński
    • Sebastian Molin
    • Piotr Jasiński
    2020 Full text JOURNAL OF SOLID STATE ELECTROCHEMISTRY

    This work evaluates the effects of the sintering temperature (800 °C, 900 °C, 1000 °C) of SrTi1-xFexO3-δ (x = 0.35, 0.5, 0.7) porous electrodes on their electrochemical performance as potential oxygen electrode materials of solid oxide cells. The materials were prepared by a solid-state reaction method and revealed the expected cubic perovskite structure. After milling, the powders were characterised by a sub-micrometre particle size with high sinter-activity. It was shown that the lowest area specific resistance was achieved after sintering SrTi0.65Fe0.35O3 electrodes at 1000 °C, and SrTi0.5Fe0.5O3 and SrTi0.30Fe0.70O3 electrodes at 800 °C, which can be considered to be a relatively low temperature. In general, EIS measurements showed that increasing the Fe content results in lowered electrode polarisation and a decrease of the series resistance. Even though the studied materials have much lower total conductivities than state-of-the-art electrode materials (e.g. (La,Sr)(Co,Fe)O3), the polarisation resistances obtained in this work can be considered low.

  • Effect of Surface Treatment of Halloysite Nanotubes (HNTs) on the Kinetics of Epoxy Resin Cure with Amines
    • Vahideh Akbari
    • Maryam Jouyandeh
    • Seyed Paran
    • Mohammad Ganjali
    • Hossein Abdollahi
    • Henri Vahabi
    • Zahed Ahmadi
    • Krzysztof Formela
    • Amin Esmaeili
    • Ahmad Mohaddespour
    • Sajjad Habibzadeh
    • Mohammad Saeb
    2020 Full text Polymers

    The epoxy/clay nanocomposites have been extensively considered over years because of their low cost and excellent performance. Halloysite nanotubes (HNTs) are unique 1D natural nanofillers with a hollow tubular shape and high aspect ratio. To tackle poor dispersion of the pristine halloysite (P-HNT) in the epoxy matrix, alkali surface-treated HNT (A-HNT) and epoxy silane functionalized HNT (F-HNT) were developed and cured with epoxy resin. Nonisothermal differential scanning calorimetry (DSC) analyses were performed on epoxy nanocomposites containing 0.1 wt.% of P-HNT, A-HNT, and F-HNT. Quantitative analysis of the cure kinetics of epoxy/amine system made by isoconversional Kissinger–Akahira–Sunose (KAS) and Friedman methods made possible calculation of the activation energy (Eα) as a function of conversion (α). The activation energy gradually increased by increasing α due to the diffusion-control mechanism. However, the average value of Eα for nanocomposites was lower comparably, suggesting autocatalytic curing mechanism. Detailed assessment revealed that autocatalytic reaction degree, m increased at low heating rate from 0.107 for neat epoxy/amine system to 0.908 and 0.24 for epoxy/P-HNT and epoxy/A-HNT nanocomposites, respectively, whereas epoxy/F-HNT system had m value of 0.072 as a signature of dominance of non-catalytic reactions. At high heating rates, a similar behavior but not that significant was observed due to the accelerated gelation in the system. In fact, by the introduction of nanotubes the mobility of curing moieties decreased resulting in some deviation of experimental cure rate values from the predicted values obtained using KAS and Friedman methods.

  • Effect of the Drying Method of Pine and Beech Wood on Fracture Toughness and Shear Yield Stress
    • Daniel Chuchała
    • Jakub Sandak
    • Kazimierz Orłowski
    • Tomasz Muziński
    • Marcin Lackowski
    • Tomasz Ochrymiuk
    2020 Full text Materials

    The modern wood converting processes consists of several stages and material drying belongs to the most influencing future performances of products. The procedure of drying wood is usually realized between subsequent sawing operations, affecting significantly cutting conditions and general properties of material. An alternative methodology for determination of mechanical properties (fracture toughness and shear yield stress) based on cutting process analysis is presented here. Two wood species (pine and beech) representing soft and hard woods were investigated with respect to four diverse drying methods used in industry. Fracture toughness and shear yield stress were determined directly from the cutting power signal that was recorded while frame sawing. An original procedure for compensation of the wood density variation is proposed to generalize mechanical properties of wood and allow direct comparison between species and drying methods. Noticeable differences of fracture toughness and shear yield stress values were found among all drying techniques and for both species, but only for beech wood the differences were statistically significant. These observations provide a new highlight on the understanding of the effect of thermo-hydro modification of wood on mechanical performance of structures. It can be also highly useful to optimize woodworking machines by properly adjusting cutting power requirements.

  • Effect of the integration into Global Value Chains on the employment contract in Central and Eastern European countries
    • Dagmara Nikulin
    • Sabina Szymczak
    2020 Full text EQUILIBRIUM Quarterly Journal of Economics and Economic Policy

    Research background: In the era of globalization, there is a need to address decent work deficits in Global Value Chains (GVCs). The forms of working conditions reveal a broad dispersion of contents. The literature review exposes hardly any Europe-focused research assessing the socioeconomic impact of global production links and going beyond their pure economic effects assessed in terms of employment, productivity or wages. Purpose of the article: This paper investigates how involvement in GVCs affects labour standards. In particular, we assess how the integration into GVCs impacts the probability of having indefinite type of employment contract, which stands for one of the decent work indicator. Moreover, we draw individual and firm-level characteristics determining the type of employment contract. Methods: We use linked employer-employee data from the Structure of Earnings Survey merged with industry-level statistics on GVCs based on World Input-Output Database — the sample is composed of over 5 million workers from 10 Central and Eastern European countries (CEEC) observed in 2014. The involvement into GVCs is measured using a novel approach based on the concepts of global import intensity (GII). We employ logistic regression with robust standard errors. Findings & Value added: Controlling for individual and firm-level characteristics (sex, age, education level, length of service in enterprise, size of the enterprise) we find that greater integration into GVCs increases the probability of having temporary type of employment contract, mainly in tradable sectors. However, across CEE countries the relation between GVC and employment type is mixed. In this way we expand the existing literature by reporting the effects of GVCs on labour standards in CEEC.

  • Effect of Thermal Treatment of Birch Wood by Saturated Water Vapor on Granulometric Composition of Chips from Sawing and Milling Processes from the Point of View of Its Processing to Composites
    • Richard Kminiak
    • Kazimierz Orłowski
    • Ladislav Dzurenda
    • Daniel Chuchała
    • Adrian Banski,
    2020 Full text Applied Sciences-Basel

    The goal of this work is to investigate the impact of thermal modification of birch wood with saturated steam on the particle size distribution of the sawing and milling process. Birch wood (Betula pendula Roth) is an excellent source to produce plywood boards. Wastes from mechanical processing of birch wood are suitable to produce composite materials. Granulometric analyses of chips from sawing processes on the PRW 15M frame saw, as well as on the 5-axis CNC machining centre SCM TECH Z5 and the 5-axis CNC machining centre AX320 Pinnacle, proved that more than 95% of chips are chips of coarse and medium coarse chip fractions with dimensions above 0.125 mm. Depending on the shape, coarse and medium-thick chips belong to the group of fiber chips, the length of which is several times greater than the width and thickness. Fine fractions with dimensions smaller than 125 μm are isometric chips that are approximately the same size in all three dimensions. Thoracic dust fractions below 30 μm were not measured. The performed analyses showed that the heat treatment of birch wood with saturated steam did not affect the grain size of chips formed in sawing and milling processes on CNC machining centre and can be used as a raw material for the production of composite materials. Fabric filters are suitable for separating chips extracted from frame saws, PRW-15M or machining centre. Environmental criteria for the separation of chips from transport air in textile filters are met by filters with a fabric classified in class G4.

  • Effective Collaboration of Entrepreneurial Teams—Implications for Entrepreneurial Education
    • Beata Krawczyk-Bryłka
    • Katarzyna Stankiewicz
    • Paweł Ziemiański
    • Michał Tomczak
    2020 Full text Education Sciences

    In the situation of a permanent change and increased competition, business ventures are more and more often undertaken not by individuals but by entrepreneurial teams. The main aim of this paper is to examine the team principles implemented by eective entrepreneurial teams and how they dier in nascent and established teams. We also focused on the relationship between the implementation of these rules by entrepreneurial team members and their evaluation of venture performance and personal satisfaction. The quantitative method was used: a list of nine items describing the principles important for the entrepreneurial teams’ collaboration was included in a questionnaire conducted in a group of 106 Polish entrepreneurs who run their businesses as members of entrepreneurial teams. The results of the research showed that all the collaboration principles included in the prepared scale are implemented by the tested entrepreneurial teams; in the case of two particular items, the obtained scores were higher in nascent teams. The correlation between principle implementation and venture performance as well as the correlation between principle implementation and entrepreneurs’ professional satisfaction was confirmed. In addition, the goal was to emphasize the importance of the entrepreneurial team’s collaboration due to its eectiveness, and propose the prepared scale as a tool for entrepreneurial reflective learning. Finally, statements by members of two entrepreneurial teams concerning team collaboration are presented to deliver case studies that can be used during entrepreneurship courses.

  • Effective Permeability of Multi Air Gap Ferrite Core 3-Phase Medium Frequency Transformer in Isolated DC-DC Converters
    • Piotr Dworakowski
    • Andrzej Wilk
    • Michał Michna
    • Bruno Lefebvre
    • Fabien Sixdenier
    • Michel Mermet-Guyennet
    2020 Full text ENERGIES

    The magnetizing inductance of the medium frequency transformer (MFT) impacts the performance of the isolated dc-dc power converters. The ferrite material is considered for high power transformers but it requires an assembly of type “I” cores resulting in a multi air gap structure of the magnetic core. The authors claim that the multiple air gaps are randomly distributed and that the average air gap length is unpredictable at the industrial design stage. As a consequence, the required effective magnetic permeability and the magnetizing inductance are difficult to achieve within reasonable error margins. This article presents the measurements of the equivalent B(H) and the equivalent magnetic permeability of two three-phase MFT prototypes. The measured equivalent B(H) is used in an FEM simulation and compared against a no load test of a 100 kW isolated dc-dc converter showing a good fit within a 10% error. Further analysis leads to the demonstration that the equivalent magnetic permeability and the average air gap length are nonlinear functions of the number of air gaps. The proposed exponential scaling function enables rapid estimation of the magnetizing inductance based on the ferrite material datasheet only.

  • Effectiveness of toluene separation from gas phase using supported ammonium ionic liquid membrane
    • Iwona Cichowska-Kopczyńska
    • Robert Aranowski
    2020 Full text CHEMICAL ENGINEERING SCIENCE

    Ammonium ionic liquids (ILs) are relatively cheap in synthesis and environmentally benign and despite that they have been very rarely used in gas separation. In this research we used several ammonium ILs as liquid membranes for removal of residual toluene from gas phase. Ionic liquids used in this study were composed of bis(trifluoromethylsulfonyl)imide anion [Tf2N] and trimethylbutylammonium [N1114], trietylbutylammonium [N2224], trietylhexylammonium [N2226], trietyloctylammonium [N2228] cations. Selected ILs formed stable membranes with limited swelling effect and good performance. The highest toluene permeability was recorded for [N2228][Tf2N] of 2666 barrers and for triethyl based ILs it was decreasing with carbon atoms number. The selectivity of toluene/N2 separation was in a range of 29 to 120. For better process illustration, the factors influencing the permeation process, namely viscosity and partition coefficients were examined.

  • Effects of Bromine Doping on the Structural Properties and Band Gap of CH3NH3Pb(I1–xBrx)3 Perovskite
    • Miłosz Martynow
    • Damian Głowienka
    • Yulia Galagan
    • Julien Guthmuller
    2020 Full text ACS Omega

    An experimental and theoretical study is reported to investigate the influence of bromine doping on CH3NH3Pb(I1−xBrx)3 perovskite for Br compositions ranging from x = 0 to x = 0.1, in which the material remains in the tetragonal phase. The experimental band gap is deduced from UV−vis absorption spectroscopy and displays a linear behavior as a function of bromine concentration. Density functional theory calculations are performed for five different series of randomly doped structures in order to simulate the disorder in bromine doping sites. The computations predict a linear variation of the lattice parameters, supercell volume, density, band gap, and formation energy in the considered doping range. The calculated evolution of the band gap as the function of Br doping is in excellent agreement with the experimental data, provided that different Br doping configurations are included in the simulations. The analysis of the structural and electronic properties shows a correlation between the increase of the band gap and the increased distortion of the Pb(I1−xBrx)6 octahedrons. Additionally, the simulations suggest that in CH3NH3Pb(I1−xBrx)3 bromine doping is likely to occur at both the equatorial and apical positions of the octahedrons.

  • Effects of Ca2+, Mg2+, Na+, and K+ substitutions on the microstructure and electrical properties of GdCoO3 ceramics
    • Sea-Fue Wang
    • Yung-Fu Hsu
    • Yi-Le Liao
    • Tung Lin
    • Piotr Jasiński
    2020 JOURNAL OF ELECTROCERAMICS

    GdCoO3-δ, Gd0.975Na0.025CoO3-δ, Gd0.98K0.02CoO3-δ, Gd0.98Ca0.02CoO3-δ, and GdCo0.99Mg0.01O3-δ ceramics were prepared via a solid-state reaction route. Among the dopants studied, substitution with Ca2+ slightly enhanced the densfication of GdCoO3 ceramics. All the lattice parameters of the doped ceramics were larger than those of pure GdCoO3-δ ceramic (a = 5.223 Å, b = 5.389 Å and c = 7.451 Å), and their cell volumes increased by 0.30% to 1.40% because the substitution ions were larger in size. X-ray diffraction and scanning electron microscopy results indicate that no second phase is present. The average grain size of the GdCoO3 ceramics (7.6 μm) slightly increased by the Na+, K+ and Mg2+ substitutions and decreased by the Ca2+ substitution. In all cases, the intergranular fracture surfaces revealed the presence of trapped pores due to rapid grain growth. The oxidation states and percentages of Co ions were determined from the Co 2p X-ray photoelectron spectra. Na+, K+, Ca2+, and Mg2+ substitution in the GdCoO3-δ ceramic resulted in slight oxidation of the Co ions accompanied by a decrease in oxygen vacancies. After porosity correction using the Bruggeman effective medium approximation, Gd0.98Ca0.02CoO3-δ had the largest electrical conductivity at all measured temperatures among the compositions studied, which was 144% higher at 500 °C and 16% higher at 800 °C compared to those of GdCoO3-δ ceramic (500 °C: 133.3 S·cm−1; 800 °C: 692.4 S·cm−1). The substantial increase in the electrical conductivity of the doped GdCoO3-δ ceramics is due to the electronic compensation of acceptor doping, Na′′Gd, K′′Gd, and Ca′Gd, which resulted in the formation of hole carriers and the elimination of oxygen vacancies (V∙∙o), which generated additional Co4+ (Co∙Co).

  • Effects of CO2 and Nd:YAG Laser Remelting of the Ti6Al4V Alloy on the Surface Quality and Residual Stresses
    • Magdalena Jażdżewska
    2020 Full text Advances in Materials Science

    The titanium alloys are materials susceptible to tribological wear and the laser treatment can be applied in surface treatment processes to obtain for example higher hardness level. From the other side, it is important to take into consideration, that hardness increase that can be connected with cracks . The aim of this research was to investigate the effects of different lasers and the process parameters on the form and level of residual stresses in the Ti6Al4V alloy, which determine the initiation and propagation of cracking. Two lasers were used, the CO2 and Nd:YAG lasers. The specimens were remelted in liquid nitrogen, water or calm air at different pre-heating temperature. The different laser power and scan rates were applied. The increase in energy density increased the number of cracks, the change of an environment and pre-heating affected alo the surface cracking. The cracks observed after remelting with Nd:YAG laser were longer than those observed after treatment with CO2 laser. The compressive stresses after the CO2 laser treatment, and tensile stresses after treatment with the Nd:YAG laser, were found. The appearance of cracks was attributed to an excessive energy density. The different distribution of heat energy inside and around the laser tracks was discussed as the origin of presence either tensile or compressive stresses in the alloy treated with different lasers

  • Effects of Micro-Arc Oxidation Process Parameters on Characteristics of Calcium-Phosphate Containing Oxide Layers on the Selective Laser Melted Ti13Zr13Nb Alloy
    • Magda Dziaduszewska
    • Andrzej Zieliński
    • Tomasz Seramak
    • Masaya Shimabukuro
    • Takao Hanawa
    2020 Full text Coatings

    Titania-based films on selective laser melted Ti13Zr13Nb have been formed by micro-arc oxidation (MAO) at different process parameters (voltage, current, processing time) in order to evaluate the impact of MAO process parameters in calcium and phosphate (Ca + P) containing electrolyte on surface characteristic, early-stage bioactivity, nanomechanical properties, and adhesion between the oxide coatings and substrate. The surface topography, surface roughness, pore diameter, elemental composition, crystal structure, surface wettability, and the early stagebioactivity in Hank’s solution were evaluated for all coatings. Hardness, maximum indent depth, Young’s modulus, and Ecoating/Esubstrate, H/E, H3 /E2 ratios were determined in the case of nanomechanical evaluation while the MAO coating adhesion properties were estimated by the scratch test. The study indicated that the most important parameter of MAO process influencing the coating characteristic is voltage. Due to the good ratio of structural and nanomechanical properties of the coatings, the optimal conditions of MAO process were found at 300 V during 15 min, at 32 mA or 50 mA of current, which resulted in the predictable structure, high Ca/P ratio, high hydrophilicity, the highest demonstrated early-stage bioactivity, better nanomechanical properties, the elastic modulus and hardness well close to the values characteristic for bones, as compared to specimens treated at a lower voltage (200 V) and uncoated substrate, as well as a higher critical load of adhesion and total delamination.

  • Effects of the Origin and Deacetylation Degree of Chitosan on Properties of Its Coatings on Titanium
    • Milena Supernak-Marczewska
    • Andrzej Zieliński
    2020 Full text Coatings

    The properties of chitosan coatings on titanium surfaces may be influenced by a variety of factors, including their chemical characteristics and the deposition method. The aim of this research was to determine the influence of a chitosan’s origin (a type of shrimp) and deacetylation degree (DD), when deposited on a very smooth titanium surface, on adhesion and biological behavior. The tests were performed using chitosan of a degree of 87% or 84% of deacetylation and that originated from armor crabs or shrimp armor. The technology of fabrication of chitosan coatings was by surface polishing to a smooth surface, oxidation in air, and immersion in a chitosan solution. The surface topographies were analyzed with an atomic force microscope and their water contact angles were measured by a falling drop method with a goniometer. The bioactivity tests were done in in vitro on osteogenic cells, type MC3T3-E1, with a biological microscope. The abrasion of the coatings was examined using a nano tribotester. The obtained results revealed that the adhesion of the coatings onto a smooth, oxidized titanium surface is appropriate as they remain sufficiently adjacent to the surface after wear tests. The source of chitin has a significant influence on biological properties, and the deacetylation degree is much less critical. The performed tests demonstrated the crucial role that the source of chitosan and the applicability of the applied surface treatment play in the preparation of chitosan coatings.

  • Efficiency of pollutants removal from landfill leachates using Nb/BDD and Si/BDD anodic oxidation
    • Barbara Wilk
    • Sylwia Fudala-Książek
    • Małgorzata Szopińska
    • Michał Sobaszek
    • Robert Bogdanowicz
    • Aneta Łuczkiewicz
    2020

    Landfill leachates (LLs) is a complex, refectory and difficult to depurate liquid generated from sanitary landfills. It contains excessive levels of biodegradable and in particular non-biodegradable products (e.g. heavy metals, phenols, sulphide, plasticisers). LLs are among the effluents that may pose major environmental concerns, they can be a dangerous source of pollution e.g. due to infiltration into soil and underlying water. The biological refractory nature of LLs makes it necessary to search effective, alternative (other than biodegradation) methods to reduce the contaminant loading of these effluents.In this study, the role of the BDD anodes, with different content of boron and substrates such as silicone and niobium was evaluated in the removal of macropollutants and selected MPs from LLs. By-products formed during electrolysis have been identified, too. The investigations have shown that macropollutants removal efficiency increases with higher applied current density (but also the energetic costs do). The best anode substrate was Nb, yielding very positive pollutants reduction results (better than Si substrate). Moreover, this substrate was durable and resistant to damage. The highest efficiency of macropollutants removal was achieved at 100mA/cm2 current density by BDD 0.5k, Nb (COD= 97.1%, BOD20=93.8%, N-NH4+=62%, TN=29.3%) followed by BDD 10k, Nb (COD= 86.3%, BOD20=63.5%, N-NH4+=40%, TN=34.5%). BDD electrodes were also tested in terms of MPs removal. The obtained results indicate that the BDD10k/Nb anodic oxidation in 0.1 M phosphate buffer solution (pH 7.8) is able to degrade BPA with approximately 80% efficiency, diclofenac sodium with 60%, trimethoprim 96%, sulfamethoxazole 94%, PFOA 90% and PFOS 90%. It was preliminarily found that BDD 0.5k electrode is the most efficient at investigated MPs removal (e.g. BPA removal with 90% efficiency, diclofenac sodium with 85%). Formation of by-products during this process was also observed, e.g. m/z=243 and m/z=241 for BPA, m/z=264 for diclofenac sodium, m/z=284 and m/z =299 for sulfamethoxazole. It can be concluded that BDD/Nb is a promising material in wastewater treatment. The results confirmed high performance of BDD electrodes in pollutants removal from the studied matrixes, nevertheless this method still requires further optimization.

  • Efficient Method for the Concentration Determination of Fmoc Groups Incorporated in the Core-Shell Materials by Fmoc–Glycine
    • Elzbieta Szczepanska
    • Beata Grobelna
    • Jacek Ryl
    • Amanda Kulpa
    • Tadeusz Ossowski
    • Pawel Niedzialkowski
    2020 Full text MOLECULES

    In this paper, we described the synthesis procedure of TiO2@SiO2 core-shell modified with 3-(aminopropyl)trimethoxysilane (APTMS). The chemical attachment of Fmoc–glycine (Fmoc–Gly–OH) at the surface of the core-shell structure was performed to determine the amount of active amino groups on the basis of the amount of Fmoc group calculation. We characterized nanostructures using various methods: transmission electron microscope (TEM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) to confirm the modification effectiveness. The ultraviolet-visible spectroscopy (UV-vis) measurement was adopted for the quantitative determination of amino groups present on the TiO2@SiO2 core-shell surface by determination of Fmoc substitution. The nanomaterials were functionalized by Fmoc–Gly–OH and then the fluorenylmethyloxycarbonyl (Fmoc) group was cleaved using 20% (v/v) solution of piperidine in DMF. This reaction led to the formation of a dibenzofulvene–piperidine adduct enabling the estimation of free Fmoc groups by measurement the maximum absorption at 289 and 301 nm using UV-vis spectroscopy. The calculations of Fmoc loading on core-shell materials was performed using different molar absorption coefficient: 5800 and 6089 dm3 × mol−1 × cm−1 for λ = 289 nm and both 7800 and 8021 dm3 × mol−1 × cm−1 for λ = 301 nm. The obtained results indicate that amount of Fmoc groups present on TiO2@SiO2–(CH2)3–NH2 was calculated at 6 to 9 µmol/g. Furthermore, all measurements were compared with Fmoc–Gly–OH used as the model sample

  • EIA in teaching sustainable development and environmental protection in engineering education
    • Aleksandra Sas-Bojarska
    2020 Full text World Transactions on Engineering and Technology Education

    A multifaceted approach in teaching the environmental impact assessment (EIA) as a way to stress the role of environmental education in technical sciences is the focus of this article. The EIA is an example of an effective tool that supports spatial planning in implementing sustainable development. The aim is to present the idea and benefits of a facilitative and collaborative approach in teaching the EIA, stressing the role of student co-operation and involvement, as well as a participatory and interdisciplinary approach. Inspiring controversial case studies present different problems and approaches as examples of best practice. The teaching method underlies the necessity of understanding wider processes leading to environmental threats and the ways to prevent them, crossing different disciplines. Such an approach, attractive to students, can present the EIA not only as a formal procedure, but as a useful tool for environmental protection. Consequently, it may strengthen the student’s future activities in implementing the idea of sustainable development in practice.

  • Ekspertyza dotycząca opinii geotechnicznej na temat stanu podłoża gruntowego pod budynkiem w północnej części Dworca Głównego w Gdańsku.
    • Rafał Ossowski
    • Marcin Cudny
    • Mariusz Wyroślak
    2020

    Opinia przygotowana na podstawie umowy zawartej w Gdańsku, pomiędzy Mostostal Warszawa Spółka Akcyjna z siedzibą: 02-673 Warszawa, ul. Konstruktorska 12A oraz Politechniką Gdańską, Wydział Inżynierii Lądowej i Środowiska z siedzibą przy ul. Gabriela Narutowicza 11/12, 80-233 Gdańsk.

  • Ekspertyza dotycząca ustalenia przyczyn nieszczelności ścian szczelinowych oraz płyty fundamentowej wraz z propozycją rozwiązania naprawczego mającego na celu skuteczne uszczelnienie (likwidację przecieków) kondygnacji podziemnych budynku biurowego LPP FASHION LAB zlokalizowanego w Gdańsku przy ulicy Łąkowej 35/26 i 37/38
    • Marcin Cudny
    • Mariusz Wyroślak
    • Maciej Niedostatkiewicz
    • Rafał Ossowski
    2020

    Zlecenie firmy Mostostal SA z siedzibą w Warszawie przy ulicy Konstruktorskiej 12A na wykonanie ekspertyzy technicznej dotyczącej ustalenia przyczyn nieszczelności ścian szczelinowych oraz płyty fundamentowej wraz z propozycją rozwiązania naprawczego mającego na celu skuteczne uszczelnienie (likwidacje przecieków) kondygnacji podziemnych budynku biurowego LPP FASHION LAB zlokalizowanego w Gdańsku przy ulicy Łąkowej 35/36 i 37/38.

  • Ekspertyza techniczna w zakresie wyjaśnienia oznaczeń „j.mb.”, „j.bt.” i „bet.” znajdujących się na mapie zasadniczej, w odniesieniu do przepisów Prawa Budowlanego i stanu faktycznego.
    • Joanna Wojtas
    • Stefan Niewitecki
    2020

    W ekspertyzie odniesiono się do definicji drogi, jako budowli zgodnie z definicjami ustawy Prawa Budowlanego i przepisów pokrewnych. Ponadto wyjaśniono oznaczenia obszarów: jezdni i nawierzchni znajdujących się na mapie zasadniczej - mapie do celów projektowych w odniesieniu do obowiązujacych przepisów oraz stanu faktycznego.

  • Eksperyment: Ekslibris
    • Krzysztof Wróblewski
    2020

    Eksperyment: Ekslibris Wystawa online 12 eksperymentalnych ekslibrisów inspirowanych wybranymi książkami Güntera Grassa, stworzonych specjalnie dla Gdańskiej Galerii Miejskiej przez zaproszonych do projektu artystów. Przy okazji cotygodniowej inauguracji poszczególnych ekslibrisów, będziemy przybliżać Wam sylwetki każdego z artystów, a także przypominać ważne dla nich projekty, w których wzięli udział. Produktem finalnym całego projektu, oprócz wystawy online, będzie kalendarz na rok 2021 ilustrowany powstałymi ekslibrisami i opatrzony komentarzem kuratorskim. Wszystkie powstałe prace trafią do kolekcji Gdańskiej Galerii Miejskiej. Artyści: Alicja Karska i Aleksandra Went, Tomasz Kopcewicz, Agata Nowosielska, Anna Orbaczewska, Patrycja Orzechowska, Maciek Salamon, Dominika Skutnik, Dorota Walentynowicz, Adam Witkowski, Ania Witkowska, Krzysztof Wróblewski, Marcin Zawicki Kuratorka: Marta Wróblewska Projekt animacji: Katarzyna Łygońska Projekt identyfikacji wizualnej: Patrycja Orzechowska Udźwiękowienie animacji: Piotr Kaliński Kuratorka pragnie szczególnie podziękować Dominice Skutnik za impuls do odkrycia potencjału sztuki ekslibrisu i podjęcia próby przeniesienia jej we współczesne realia artystyczne.

  • E-LEARNING NA POLITECHNICE GDAŃSKIEJ - HISTORIA ROZWOJU W LATACH 1995-2020
    • Anita Dąbrowicz-Tlałka
    • Anna Grabowska
    2020 Full text

    Internet oraz kształcenie oparte na wykorzystaniu e-technologii stały się nieodłącznym elementem edukacji. Artykuł przedstawia zarys historii rozwoju e-learningu na Politechnice Gdańskiej, przykładowe rozwiązania technologiczne, elementy tworzenia struktur organizacyjnych oraz związanych z legislacją, a także wybrane projekty wykorzystujące szeroko pojęte e-technologie w edukacji akademickiej realizowanej na Uczelni

  • Electric and magnetic properties of Lanthanum Barium Cobaltite
    • Iga Szpunar
    • Sebastian Lech Wachowski
    • Tadeusz Miruszewski
    • Kacper Dzierzgowski
    • Karolina Górnicka
    • Tomasz Klimczuk
    • Magnus H. Sorby
    • Maria Balaguer
    • José M Serra
    • Ragnar Strandbakke
    • Aleksandra Dorota Mielewczyk-Gryń
    • Maria Gazda
    2020 Full text JOURNAL OF THE AMERICAN CERAMIC SOCIETY

    The cubic Ba0.5La0.5CoO3‐δ was synthesized using solid state reaction. The structural properties were determined by the simultaneous refinement of Synchrotron Powder X‐ray Diffraction and Neutron Powder Diffraction data. Iodometric titration was used to examine the oxygen stoichiometry and average cobalt oxidation state. Low‐temperature magnetic studies show soft ferromagnetic character of fully oxidized material, with θP = 198(3) K and μeff = 2.11(2) μB. Electric measurements show the thermally activated nature of conductivity at low temperatures, whereas, due to the variable oxidation and spin state of cobalt, a single charge transport mechanism cannot be distinguished. Around room temperature, a wide transition from thermally activated conductivity to semi‐metallic behavior is observed. Under the inert atmos-phere, the oxygen content lowers and the cation ordering takes place, leading to coex-istence of two, ordered and disordered, phases. As a result of this change, thermally activated conductivity is observed also at high temperatures in inert atmosphere.

  • ELECTRICAL CONDUCTIVITY AND pH IN SURFACE WATER AS TOOL FOR IDENTIFICATION OF CHEMICAL DIVERSITY
    • Joanna Potapowicz
    • Danuta Szumińska
    • Małgorzata Szopińska
    • Czapiewski Sebastian
    • Żaneta Polkowska
    2020 Full text Ecological Chemistry and Engineering S - Chemia i Inżynieria Ekologiczna S

    In the present study, the creeks and lakes located at the western shore of Admiralty Bay were analysed. The impact of various sources of water supply was considered, based on the parameters of temperature, pH and specific electrolytic conductivity (SEC25). All measurements were conducted during a field campaign in January-February 2017. A multivariate dataset was also created and a biplot of SEC25 and pH of the investigated waters was performed. The average temperatures of the investigated waters were 0.10-8.10 °C. The pH values indicate that most of the water environments of the analysed area are slightly acidic to alkaline (5.26-8.50) with two exceptions: Siodlo II Creek (9.26) and Petrified Forest Creek (8.95), which are characterised by greater alkalinity. At the measurement points closest to the Baranowski Glacier and Ecology Glacier, SEC25 values were the lowest (26.8-61.1 μS·cm–1), while the remaining values ranged from 79.0 to 382 μS·cm–1 for the whole studied area. Based on the results it is concluded that the periodic intensive inflow of ablation waters, combined with morphological changes in the glacier front, causes a significant variability in the outflow network, creating the conditions for changes in basic physicochemical parameters. Moreover, it is observed that local depressions in the terrain form sedimentation traps in which, alongside fine-grained deposits, compounds can accumulate that originate from in situ sedimentation and that are also associated with surface runoff from the melting of snow cover, buried ice and permafrost.

  • Electrical conductivity of nanostructured acceptor-doped ceria fabricated by spark plasma sintering (SPS)
    • Ahsanul Kabir
    • Sofie Colding-Jørgensen
    • Sebastian Molin
    • Vincenzo Esposito
    2020 MATERIALS LETTERS

    High purity nanoscale powders (~10–15 nm size) of two different compositions of ceria, doped with Gd3+ and Ca2+, have been consolidated by spark plasma sintering (SPS) at different temperatures. Fully-dense samples were observed only at a sintering temperature of 980 °C. The as-sintered samples showed rather fast grain growth with an average grain size below 300 nm. The electrical properties of the samples were evaluated by impedance spectroscopy over a wide range of temperatures (300–550 °C) in air. Electrical conductivity significantly enhanced with increasing sintering temperature. The compounds show an electrical blocking effect at the grain boundary, depending on the doping cations.

  • Electrochemical and in silico approaches for liver metabolic oxidation of antitumor-active triazoloacridinone C -1305
    • Agnieszka Potęga
    • Dorota Żelaszczyk
    • Zofia Mazerska
    2020 Full text Journal of Pharmaceutical Analysis

    5-Dimethylaminopropylamino-8-hydroxytriazoloacridinone (C-1305) is a promising antitumor compound developed in our laboratory. A better understanding of its metabolic transformations is still needed to explain the multidirectional mechanism of pharmacological action of triazoloacridinone derivatives at all. Thus, the aim of the current work was to predict oxidative pathways of C-1305 that would reflect its phase I metabolism. The multi-tool analysis of C-1305 metabolism included electrochemical conversion and in silico sites of metabolism predictions in relation to liver microsomal model. In the framework of the first approach, an electrochemical cell was coupled on-line to an electrospray ionization mass spectrometer. The effluent of the electrochemical cell was also injected onto a liquid chromatography column for the separation of different products formed prior to mass spectrometry analysis. In silico studies were performed using MetaSite software. Standard microsomal incubation was employed as a reference procedure. We found that C-1305 underwent electrochemical oxidation primarily on the dialkylaminoalkylamino moiety. An unknown so far N-dealkylated and hydroxylated C-1305 products have been identified. The electrochemical system was also able to simulate oxygenation reactions. Similar pattern of C-1305 metabolism has been predicted using in silico approach. Both proposed strategies showed high agreement in relation to the generated metabolic products of C-1305. Thus, we concluded that they can be considered as simple alternatives to enzymatic assays, affording time and cost efficiency.

  • Electrochemical detection of 4,4',5,5'-tetranitro-1H,1'H-2,2'-biimidazole on boron-doped diamond/graphene nanowall electrodes
    • Anna Dettlaff
    • Paweł Jakóbczyk
    • Michał Sobaszek
    • Mateusz Ficek
    • Bartłomiej Dec
    • Aneta Łuczkiewicz
    • Mateusz Szala
    • Jacek Wojas
    • Tadeusz Ossowski
    • Robert Bogdanowicz
    2020 Full text IEEE SENSORS JOURNAL

    We present a promising approach to the electroanalytical detection of a specific nitroaromatic explosive in landfill leachates (LLs) that originated from a municipal solid waste plant. The paper is focused but not limited to the sensing of 4,4',5,5'-tetranitro-1H,1'H-2,2'-biimidazole (TNBI) using differential pulse voltammetry and cyclic voltammetry. Highly electroactive nanocarbon was applied to determine low concentrations of the analyte in the complex interfering matrix as leachate samples. The mechanism of nitro- group reduction is attributed to the sensing effect, as revealed in the voltammograms of TNBI. The developed sensor model has two linear regions extending from 0.02 ppm to 1.4 ppm and from 2 ppm to 16 ppm resulting from adsorption and diffusion-controlled processes, respectively. The limit of detection was as low as 0.52 ppm (1.66 μM L-1) thanks to the electrochemical performance of the joint effect of the diamond/graphene composite nanowall surface.

  • Electrochemical determination of nitroaromatic explosives at boron-doped diamond/graphene nanowall electrodes: 2,4,6-trinitrotoluene and 2,4,6-trinitroanisole in liquid effluents
    • Anna Dettlaff
    • Paweł Jakóbczyk
    • Mateusz Ficek
    • B. Wilk
    • M. Szala
    • J. Wojtas
    • Tadeusz Ossowski
    • Robert Bogdanowicz
    2020 Full text JOURNAL OF HAZARDOUS MATERIALS

    The study is devoted to the electrochemical detection of trace explosives on boron-doped diamond/graphene nanowall electrodes (B:DGNW). The electrodes were fabricated in a one-step growth process using chemical vapour deposition without any additional modifications. The electrochemical investigations were focused on the determination of the important nitroaromatic explosive compounds, 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitroanisole (TNA). The distinct reduction peaks of both studied compounds were observed regardless of the pH value of the solution. The reduction peak currents were linearly related to the concentration of TNT and TNA in the range from 0.05–15 ppm. Nevertheless, two various linear trends were observed, attributed respectively to the adsorption processes at low concentrations up to the diffusional character of detection for larger contamination levels. The limit of detection of TNT and TNA is equal to 73 ppb and 270 ppb, respectively. Moreover, the proposed detection strategy has been applied under real conditions with a significant concentration of interfering compounds – in landfill leachates. The proposed bare B:DGNW electrodes were revealed to have a high electroactive area towards the voltammetric determination of various nitroaromatic compounds with a high rate of repeatability, thus appearing to be an attractive nanocarbon surface for further applications.

  • Electrochemical oxidation of PFOA and PFOS in landfill leachates at low and highly boron-doped diamond electrodes
    • Mattia Pierpaoli
    • Małgorzata Szopińska
    • Barbara Wilk
    • Michał Sobaszek
    • Aneta Łuczkiewicz
    • Robert Bogdanowicz
    • Sylwia Fudala-Książek
    2020 Full text JOURNAL OF HAZARDOUS MATERIALS

    Polyfluorinated alkyl substances (PFASs) may reach landfill leachates (LLs) due to improper waste management. In this study perfluorooctanoate (PFOA) and perfluorooctane sulphonate (PFOS) were used as representatives of PFASs in the decomposition on boron-doped diamond electrodes (BDDs) with high (10k ppm) and low (0.5k ppm) boron doping concentrations. The result shows that although better COD removal efficacies are obtained on the low-doped BDD (59 % after 8 h), the decomposition rate of PFOA and PFOS was not affected by boron doping. In LLs, at the current density of 75 mA/cm2, averaged removal efficiencies of 80 % and 78 % were achieved for PFOA and PFOS, respectively. But besides concentration of mother compounds, the presence of intermediates during electrolysis should be monitored. After 8 h of LL electrolysis, the presence of long-chain degradates C6 F13 and C6 F13 COO˗ was still observed only in 10k BDD-PFOA assays, while during 0.5k assays C 6F13 and C6 F13 COO˗ form more intesively at the beginning of the process. This indirectly confirms the more intensive generation of perfluoroalkoxy and hydroxyl radicals and higher susceptibility to electrolysis of PFOA’s long-chain intermediates on 0.5k BDD. This is the first study reporting BDD-electrolysis as promising in PFAS removal from the complex matrix of LLs, despite the oxidation of competing LLs components.

  • Electrochemical performance of thin free-standing boron-doped diamond nanosheet electrodes
    • Robert Bogdanowicz
    • Mateusz Ficek
    • Natalia Malinowska
    • Sanju Gupta
    • Romney Meek
    • Paweł Niedziałkowski
    • Michał Rycewicz
    • Sawczak Mirosław
    • Jacek Ryl
    • Tadeusz Ossowski
    2020 Full text JOURNAL OF ELECTROANALYTICAL CHEMISTRY

    In the following work we describe preparation and the electrochemical performance of thin and free-standing heavy boron-doped diamond (BDD) nanosheets. The investigated foils were deposited on Ta substrate using microwave plasma-enhanced chemical vapor deposition technique (MPECVD). Foils of two B-dopant densities were investigated, obtained on the base of 10 k and 20 k ppm [B]/[C] ratio in the gas admixture. The obtained foils can be easily peeled from substrate in deionized water to be then attached to other material, in this case polydimethylsiloxane (PDMS). We have shown that the top surface and the bottom side of investigated boron-doped diamond nanosheet possess significantly altered morphology and physico-chemical properties, revealed by electron microscopy, Raman spectroscopy and electrochemistry. The voltammetric response of investigated BDD foils as working electrodes indicates the highest activity for the nanosheet with higher dopant concentration, in particular on its top surface. Furthermore, electrodes are characterized with altered kinetics, characteristic for partially blocked electrodes with quasi-reversible charge transfer.

  • Electrochemical, theoretical and surface physicochemical studies of the alkaline copper corrosion inhibition by newly synthesized molecular complexes of benzenediamine and tetraamine with π acceptor
    • Mohamed Ibrahim
    • Gaber Mersal
    • Ahmed Fallatah
    • Murat Saracoglu
    • Fatma Kandemirli
    • Sarah Alharthi
    • Sabine Szunerits
    • Rabah Boukherroub
    • Jacek Ryl
    • Mohammed Amin
    2020 JOURNAL OF MOLECULAR LIQUIDS

    Two charge transfer complexes, namely [(BDAH)+(PA−)] CT1 [(BTAH)2+(PA−)2] and CT2 (BDAH = 1,2-benzenediamine, BTAH = 1,2,4,5-benzenetetramine, and PA− = 2,4,6-trinitrophenolate), were synthesized and fully characterized using various spectroscopic techniques. CT1 and CT2 were tested as inhibitors to effectively control the uniform and anodic corrosion processes of copper in an alkaline electrolyte (1.0 M KOH) using various electrochemical techniques. As a reference point, results were compared with the potassium salt of the π-acceptor potassium 2,4,6-trinitrophenolate (designated here as PA−K+). The highest inhibition efficiency (97%) was recorded for inhibitor CT2 at a concentration of 1.0 mM. The inhibition mechanism was discussed based on scanning electron microscopy and X-ray photoelectron spectroscopy results of the corroded and inhibited Cu surfaces. A theoretical study, based on quantum-chemical calculations of the synthesized compounds, performed by the DFT/B3LYP method with a 6-311++G(2d,2p) basis set by using Gaussian 09, Revision A.02 program, was also included to support experimental findings. The various quantum chemical parameters such as EHOMO, ELUMO, chemical hardness, and chemical softness of the investigated molecules were calculated, and their correlation with the inhibition efficiency of the synthesized compounds was discussed.

  • Electrochemically directed biofunctionalization of a lossy-mode resonance optical fiber sensor
    • Monika Janik
    • Paweł Niedziałkowski
    • Katarzyna Lechowicz
    • Marcin Koba
    • Petr Sezemsky
    • Vitezslav Stranak
    • Tadeusz Ossowski
    • Mateusz Śmietana
    2020 Full text OPTICS EXPRESS

    In this work, we present a direct electrochemical biofunctionalization of an indium-tin-oxide-coated lossy-mode resonance optical fiber sensor. The functionalization using a biotin derivative was performed by cyclic voltammetry in a 10 mM biotin hydrazide solution. All stages of the experiment were simultaneously verified with optical and electrochemical techniques. Performed measurements indicate the presence of a poly-biotin layer on the sensor’s surface. Furthermore, dual-domain detection of 0.01 and 0.1 mg/mL of avidin confirms the sensor’s viability for label-free detection.

  • Electro-chemo-mechanical properties in nanostructured Ca-doped ceria (CDC) by field assisted sintering
    • Ahsanul Kabir
    • Haiwu Zhang
    • Sofie Colding-Jørgensen
    • Simone Santucci
    • Sebastian Molin
    • Vincenzo Esposito
    2020 Full text SCRIPTA MATERIALIA

    Recent investigations have shown that highly oxygen defective cerium oxides generate non-classical electrostriction that is superior to lead-based ferroelectrics. In this work, we report the effect of field-assisted spark plasma sintering (SPS) on electro-chemo-mechanical properties of calcium doped ceria (CDC). Nanometric powders of Ca.10 nm are rapidly consolidated to form polycrystalline nanostructures with a high degree of crystalline disorder. Remarkably, the resultant material demonstrates a large electromechanical strain without a frequency-related relaxation effect. We conclude that electromechanical activity in CDC materials strictly depends on the Ca2+- interaction, while disorder at the crystalline boundaries has a minor effect.

  • Electrodeposited Biocoatings, Their Properties and Fabrication Technologies: A Review
    • Andrzej Zieliński
    • Michał Bartmański
    2020 Full text Coatings

    Coatings deposited under an electric field are applied for the surface modification of biomaterials. This review is aimed to characterize the state-of-art in this area with an emphasis on the advantages and disadvantages of used methods, process determinants, and properties of coatings. Over 170 articles, published mainly during the last ten years, were chosen, and reviewed as the most representative. The most recent developments of metallic, ceramic, polymer, and composite electrodeposited coatings are described focusing on their microstructure and properties. The direct cathodic electrodeposition, pulse cathodic deposition, electrophoretic deposition, plasma electrochemical oxidation in electrolytes rich in phosphates andcalciumions, electro-spark, andelectro-dischargemethods are characterized. The effects of electrolyte composition, potential and current, pH, and temperature are discussed. The review demonstrates that the most popular are direct and pulse cathodic electrodeposition and electrophoretic deposition. The research is mainly aimed to introduce new coatings rather than to investigate the effects of process parameters on the properties of deposits. So far tests aim to enhance bioactivity, mechanical strength and adhesion, antibacterial efficiency, and to a lesser extent the corrosion resistance.

  • Electrodes criticality: the impact of CRMs in the leachate electrochemical oxidation
    • Mattia Pierpaoli
    • Michał Rycewicz
    • Aneta Łuczkiewicz
    • Sylwia Fudala-Książek
    • Robert Bogdanowicz
    • Maria Letizia Ruello
    2020 Full text Manufacturing Review

    . Landfill leachate possesses high concentrations of ammonia, micropollutants, and heavy metals, and are characterised for low biodegradability. For this reason, conventional treatment technologies may result ineffective for complete pollutant removal. Electrochemical oxidation allows most of the of recalcitrant pollutants to be oxidised effectively within an easy operational and acceptable retention time, without the need to provide additional chemicals, and without producing waste materials. The mineralisation efficiency and electrode durability depend on the nature of the electrode material. The conventionally adopted anodes can contain critical raw materials (CRMs), and are subject to extreme corrosion conditions. CRM-free electrodes, such as carbon and graphite-based, exhibit a lower efficiency, and are subject to faster deactivation, or, as for lead-dioxide-based electrodes, can constitute a hazard due to the release into the effluent of the coating corrosion products. In this study, the relationship between electrode type, CRM content, and the removal efficiencies of organic compounds and ammonium-nitrogen (N-NH4) was investigated. Material criticality was estimated by the supply risk with economic importance indexes reported in the 2017 EU CRM List. The COD and N-NH4 removal efficiencies were obtained from a literature analysis of 25 publications. The results show that, while single and multi-oxide-coated electrodes may contain low amounts of CRM, but with limited efficiency, borondoped diamonds (BDD) may constitute the best compromise in terms of a reduced content of CRM and a high mineralisation efficiency.

  • Electromagnetic Modeling of Microstrip Elements Aided with Artificial Neural Network
    • Łukasz Sorokosz
    • Włodzimierz Zieniutycz
    2020 Full text

    The electromagnetic modeling principle aided withartificial neural network to designing the microwave widebandelements/networks prepared in microstrip technology is proposedin the paper. It is assumed that the complete information is knownfor the prototype design which is prepared on certain substratewith certain thickness and electric permittivity. The longitudinaland transversal dimensions of new design are calculated sep-arately using the scale coefficients which are determined fromtransmission line equation. Next the artificial neural networkcan be used for final tuning which should take into accountthe dispersion of microstrip line. The verification of proposedprocedure is shown for exemplary planar UWB balun.

  • Electromagnetic Simulation with 3D FEM for Design Automation in 5G Era
    • Łukasz Balewski
    • Michał Baranowski
    • Maciej Jasiński
    • Adam Lamęcki
    • Michał Mrozowski
    2020 ZTE COMMUNICATIONS

    Electromagnetic simulation and electronic design automation (EDA) play an important role in the design of 5G antennas and radio chips. The simulation challenges include electromagnetic effects and long simulation time and this paper focuses on simulation software based on finite-element method (FEM). The state-of-the-art EDA software using novel computational techniques based on FEM can not only accelerate numerical analysis, but also enable optimization, sensitivity analysis and interactive design tuning based on rigorous electromagnetic model of a device. Several new techniques that help to mitigate the most challenging issues related to FEM based simulation are highlighted. In particular, methods for fast frequency sweep, mesh morphing and surrogate models for efficient optimization and manual design tuning are briefly described, and their efficiency is illustrated on examples involving a 5G multiple-input multiple-output (MIMO) antenna and filter. It is demonstrated that these new computational techniques enable significant reduction of time needed for design closure with the acceleration rates as large as tens or even over one hundred.

  • Electronic structure calculations in electrolyte solutions: Methods for neutralization of extended charged interfaces
    • Arihant Bhandari
    • Lucian Anton
    • Jacek Dziedzic
    • Chao Peng
    • Denis Kramer
    • Chris-Kriton Skylaris
    2020 Full text JOURNAL OF CHEMICAL PHYSICS

    Density functional theory (DFT) is often used for simulating extended materials such as infinite crystals or surfaces, under periodic boundary conditions (PBCs). In such calculations, when the simulation cell has non-zero charge, electrical neutrality has to be imposed, and this is often done via a uniform background charge of opposite sign (“jellium”). This artificial neutralization does not occur in reality, where a different mechanism is followed as in the example of a charged electrode in electrolyte solution, where the surrounding electrolyte screens the local charge at the interface. The neutralizing effect of the surrounding electrolyte can be incorporated within a hybrid quantum–continuum model based on a modified Poisson–Boltzmann equation, where the concentrations of electrolyte ions are modified to achieve electroneutrality. Among the infinite possible ways of modifying the electrolyte charge, we propose here a physically optimal solution, which minimizes the deviation of concentrations of electrolyte ions from those in open boundary conditions (OBCs). This principle of correspondence of PBCs with OBCs leads to the correct concentration profiles of electrolyte ions, and electroneutrality within the simulation cell and in the bulk electrolyte is maintained simultaneously, as observed in experiments. This approach, which we call the Neutralization by Electrolyte Concentration Shift (NECS), is implemented in our electrolyte model in the Order-N Electronic Total Energy Package (ONETEP) linear-scaling DFT code, which makes use of a bespoke highly parallel Poisson–Boltzmann solver, DL_MG. We further propose another neutralization scheme (“accessible jellium”), which is a simplification of NECS. We demonstrate and compare the different neutralization schemes on several examples.

  • Electron-impact ionization cross section calculations for 5-chloropyridine and 5-bromopyridine molecules
    • Bożena Żywicka
    • Paweł Możejko
    2020 Full text Journal of Physics : Conference Series

    The total cross sections for the single electron-impact ionization of 5-chloropyridine (5-C5H4ClN) and 5-bromopyridine (5-C5H4BrN) molecules have been calculated using binary-encounter-Bethe method for electron energies ranging from the ionization threshold up to 5 keV.

  • Electron-impact ionization cross section calculations for selected ribonucleosides
    • Paweł Możejko
    2020 Full text Journal of Physics : Conference Series

    Total cross sections for the single electron-impact ionization of selected ribonuclosides (guanosine, adenosine, cytidine and uridine) have been calculated for electron energies ranging from the ionization threshold up to 5 keV.

  • Electrophoretic Deposition and Characteristics of Chitosan–Nanosilver Composite Coatings on a Nanotubular TiO2 Layer
    • Michał Bartmański
    • Łukasz Pawłowski
    • Andrzej Zieliński
    • Aleksandra Mielewczyk-Gryń
    • Gabriel Strugała
    • Bartłomiej Cieślik
    2020 Full text Coatings

    The surface treatment of titanium implants has been applied mainly to increase surface bioactivity and, more recently, to introduce antibacterial properties. To this end, composite coatings have been investigated, particularly those based on hydroxyapatite. The present research was aimed at the development of another coating type, chitosan–nanosilver, deposited on a Ti13Zr13Nb alloy. The research comprised characterization of the coating’s microstructure and morphology, timedependent nanosilver dissolution in simulated body fluid, and investigation of the nanomechanical properties of surface coatings composed of chitosan and nanosilver, with or without a surface-active substance, deposited at different voltages for 1 min on a nanotubular TiO2 layer. The microstructure, morphology, topography, and phase composition were examined, and the silver dissolution rate in simulated body fluid, nanoscale mechanical properties, and water contact angle were measured. The voltage value significantly influenced surface roughness. All specimens possessed high biocompatibility. The highest and best adhesion of the coatings was observed in the absence of a surface-active substance. Silver dissolution caused the appearanc

  • Electrophoretic Deposition and Characterization of Chitosan/Eudragit E 100 Coatings on Titanium Substrate
    • Łukasz Pawłowski
    • Michał Bartmański
    • Gabriel Strugała
    • Aleksandra Mielewczyk-Gryń
    • Magdalena Jażdżewska
    • Andrzej Zieliński
    2020 Full text Coatings

    Currently, a significant problem is the production of coatings for titanium implants, which will be characterized by mechanical properties comparable to those of a human bone, high corrosion resistance, and low degradation rate in the body fluids. This paper aims to describe the properties of novel chitosan/Eudragit E 100 (chit/EE100) coatings deposited on titanium grade 2 substrate by the electrophoretic technique (EPD). The deposition was carried out for different parameters like the content of EE100, time of deposition, and applied voltage. The microstructure, surface roughness, chemical and phase composition, wettability, mechanical and electrochemical properties, and degradation rate at different pH were examined in comparison to chitosan coating without the addition of Eudragit E 100. The applied deposition parameters significantly influenced the morphology of the coatings. The chit/EE100 coating with the highest homogeneity was obtained for Eudragit content of 0.25 g, at 10 V, and for 1 min. Young’s modulus of this sample (24.77 ± 5.50 GPa) was most comparable to that of human cortical bone. The introduction of Eudragit E 100 into chitosan coatings significantly reduced their degradation rate in artificial saliva at neutral pH while maintaining high sensitivity to pH changes. The chit/EE100 coatings showed a slightly lower corrosion resistance compared to the chitosan coating, however, significantly exceeding the substrate corrosion resistance. All prepared coatings were characterized by hydrophilicity.

  • Elektryczne zespoły zasobnikowe jako alternatywa dla elektryfikacji nowych linii w Trójmieście = Electric Multiple Units With Energy Storage – Alternative to Electrification of New Lines in Three City
    • Dariusz Karkosiński
    • Dominika Macedońska
    • Natalia Karkosińska-Brzozowska
    2020 Automatyka Elektryka Zakłócenia

    Rozważono zastosowanie nowoczesnych zespołów trakcyjnych na liniach pasażerskich Trójmiasta. Zaproponowano budowę linii Gdańsk Śródmieście - Orunia Górna oraz odtworzenie komunikacji do północnych dzielnic Gdyni. Przeanalizowano trójmiejski układ komunikacyjny dla ruchu pociągów z zasobnikami energii. Zaproponowano trasę Orunia Górna - Wrzeszcz - Osowa - Chylonia - Port Oksywie z naprzemiennie występującymi odcinkami zelektryfikowanymi i niezelektryfikowanymi Wykonano wstępne obliczenia.

  • Elementy uczenia maszynowego na zajęciach matematyki
    • Agnieszka Bartłomiejczyk
    • Dawid Ptach
    • Marcin Wata
    2020 Full text Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    W artykule omówiono związki między matematyką kursową a wybranymi zagadnieniami związanymi z uczeniem maszynowym. Pokazano w jaki sposób proste operacje na macierzach pomagają serwisom VOD w rekomendacji tytułów filmowych zgodnych z zainteresowaniami użytkowników na podstawie ich wcześniejszych wyborów. Zaprezentowano również uproszczoną wersję algorytmu regresji wielorakiej stosowaną do wyceny nieruchomości oraz wspomniano o zastosowaniu sieci neuronowych w problemach klasyfikacyjnych.

  • Ella4Life virtual assistant - user centered design strategy - evaluation following labolatory tests
    • Mariusz Kaczmarek
    • Adam Bujnowski
    • Kamil Osiński
    • Edith Birrer
    • Tomasz Neumann
    • Barry Teunissen
    2020

    In the paper, we summarize the evaluation of Anne4Care system after laboratory tests. A group of end users, seniors over 55 years of age, rated a virtual assistant by completing a questionnaire. The objectives of the pilot evaluations are mainly to assess the feasibility, usability, acceptance and functionality of the system and the ability of the potential target user to use the system and receive valuable information from it to help them address the complex needs of elderly people. The results of the assessment will be taken into account during further product development.

  • Emission profile of butan-2-one oxime from commercially available neutral silicone sealant
    • Krzysztof Klewicz
    • Mariusz Marć
    • Bożena Zabiegała
    2020 Full text MICROCHEMICAL JOURNAL

    The paper presents results of research on emission profile of butan-2-one oxime (methyl ethyl ketoxime, MEKO) released from two types of commercially available neutral silicone sealants: silicone type ‘S’ and silicone type ‘T’. To determine the emissions from silicone samples, the system consists of a stationary emission chamber, and the thermal desorption-gas chromatography-mass spectrometry system was applied. First, the research aimed to describe the emission profile of butan-2-one oxime considering different methods of application of silicone caulk: separate strips, merged strips, and dotted. Silicone sealant was applied in these three different ways to produce varying surfaces. As a result, significant differences in the emission profile were observed for the different methods of silicone application. The greatest difference in the emission rate was found to be between those of the dot shape and those of the separate strips; the emission rate was approximately five times smaller for dot shape. Moreover, the studies focused on quantitative emissions of butan-2-one oxime over a set time period. The research results indicate that, in the emission process of butan-2-oxime from a neutral silicone sealant, there are three main stages of emission. The first stage is dynamic emission, occurring during the first few days after application. The second stage is declining emission, and the third stage is stable residual emission. Between the first and third stages, the amounts of emitted oxime differ significantly. The difference in the emissions of butan-2-one oxime between the first and last stages of emission ranged from factors of 100 to 1000.

  • Emissions of selected monoaromatic hydrocarbons as a factor affecting the removal of single-use polymer barbecue and kitchen utensils from everyday use
    • Mariusz Marć
    2020 Full text SCIENCE OF THE TOTAL ENVIRONMENT

    The main focus of this study is the emission of monoaromatic hydrocarbons because these are the preliminary factors of potential solvent and monomer residues present in single-use plastic barbecue and kitchen utensils comprising polystyrene, polypropylene, natural cellulose, and biodegradable polymers intended for use with hot meal or beverages. Herein, the emissions of monoaromatic hydrocarbons (styrene, benzene, toluene, ethylbenzene, and xylene compounds and the total volatile organic compounds (TVOC)) fromnine types of disposable plastic utensils are reported. Seventy two samples of single-use plastic utensilswere conditioned at 40 and 80 °C using a stationary emission microchamber system. The average TVOC released from the studied polystyrene, polypropylene, and natural or biodegradable utensils were (2.3 ± 1.3), (1.01 ± 0.15), and (0.48 ± 0.37) μg g−1, respectively, at 40 °C and (11.1±1.2), (46.1±9.5), and (5.5±1.1) μg g−1, respectively, at 80 °C. Significant emissions of styrene (ranged from 3.5 up to 15.3 × 103 ng∙g−1), toluene (from 2.8 up to 0.53 × 103 ng∙g−1), and ethylbenzene (from3.7 up to 5.7 × 103 ng∙g−1) fromthe studied sampleswere observed, especially at 80 °C. Thus, elevated temperatures increase the potential emission of solvent and monomer residues fromplastics and could affect the quality of consumed meals or beverages, such as taste. Additionally, to determine the possible interactions between the measured chemical compounds in the plastic utensils, the Pearson's correlation coefficients were calculated.

  • Employee Commitment Matters for CSR Practice, Reputation and Corporate Brand Performance—European Model
    • Wioleta Kucharska
    2020 Full text Sustainability

    So far, there have been no studies that explore how employee brand commitment moderates CSR practice outcomes. Employee brand commitment is often claimed as a focal input and output of the CSR. So, it means that it shapes CSR conditions. Then, it is a moderator. This study aims to verify it. Besides, commitment exists in many forms and can be achieved in many ways. Hence the question, if employees are committed to the brand, then how does it affect the outcomes of social responsibility practices such as corporate reputation or brand performance? This study analyzed a sample of 282 cases from the construction industry in Europe, using SPSS Amos and the PROCESS macro, to reveal the strong alignment of an excellent level of all three: CSR practice, corporate brand reputation, employee brand commitment. Still, it also shows that the high level of CSR practice may leverage corporate brand reputation even though employees are not brand committed. It exposes how meaningful the excellent level of CSR practice is. Moreover, the study also reveals that the lack of employee brand commitment may jeopardize reputation. So, the simplest way to achieve sustainability of brand performance is to keep employee brand commitment and CSR practice at the highest possible level to secure corporate brand reputation, which is a strong mediator between CSR practice and brand performance. The people are the company. So, in light of the study findings, it is clear that the future of corporate brands is in employees’ hands. Thus, companies should focus on improving employee commitment to achieve better corporate socialresponsibility practice outcomes. Moreover, the findings in this study present evidence supporting the importance of internal branding. This is the first study that has explored how employee brand commitment moderates CSR outcomes in a national context.

  • Employing Subjective Tests and Deep Learning for Discovering the Relationship between Personality Types and Preferred Music Genres
    • Aleksandra Dorochowicz
    • Adam Kurowski
    • Bożena Kostek
    2020 Full text Electronics

    The purpose of this research is two-fold: (a) to explore the relationship between the listeners’ personality trait, i.e., extraverts and introverts and their preferred music genres, and (b) to predict the personality trait of potential listeners on the basis of a musical excerpt by employing several classification algorithms. We assume that this may help match songs according to the listener’s personality in social music networks. First, an Internet survey was built, in which the respondents identify themselves as extraverts or introverts according to the given definitions. Their task was to listen to music excerpts that belong to several music genres and choose the ones they like. Next, music samples were parameterized. Two parametrization schemes were employed for that purpose, i.e., low-level MIRtoolbox parameters (MIRTbx) and variational autoencoder neural network-based, which automatically extract parameters of musical excerpts. The prediction of a personality type was performed employing four baseline algorithms, i.e., support vector machine (SVM), k-nearest neighbors (k-NN), random forest (RF), and naïve Bayes (NB). The best results were obtained by the SVM classifier. The results of these analyses led to the conclusion that musical excerpt features derived from the autoencoder were, in general, more likely to carry useful information associated with the personality of the listeners than the low-level parameters derived from the signal analysis. We also found that training of the autoencoders on sets of musical pieces which contain genres other than ones employed in the subjective tests did not affect the accuracy of the classifiers predicting the personalities of the survey participants.

  • ENERGY ANALYSIS OF THE PROPULSION SHAFT FATIGUE PROCESS IN A ROTATING MECHANICAL SYSTEM PART II IDENTIFICATION STUDIES – DEVELOPING THE FATIGUE DURABILITY MODEL OF A DRIVE SHAFT
    • Zbigniew Korczewski
    • Konrad Marszałkowski
    2020 Full text Polish Maritime Research

    The article presents a continuation of research carried out concerning identification of energy consequences of mechanical fatigue within a propeller shaft in a rotating mechanical system, while working under conditions of the loss of the required alignment of shaft lines. Experimental research was carried out on a physical model reflecting a full-sized real object: i.e., the propulsion system of the ship. It is proven, by means of an active experiment, that changes in propeller shaft deflection are reflected in the amount of dissipated kinetic energy of masses in rotational motion and the accumulated internal energy in its construction material. Adoption of a high-cycle fatigue syndrome, consisting of diagnostic symptoms determined from the action of the propeller shaft associated with the transformation of mechanical energy into work and heat, as well as with the generation of mechanical vibrations and elastic waves of acoustic emission, is proposed. To assess the diagnostic information quantity brought about by the defined features of propeller shaft fatigue, an experimental research program was developed and implemented, in which two statistical hypotheses are verified: the significance of the impact of the values enforcing the fatigue process, presented in the first part of the article, and the adequacy of the regression equation describing the fatigue durability of the propeller shaft in the energy aspect, constituting the second part of the article. This finally gives us the opportunity, after the appropriate translation of the model test results into full-sized real objects, to develop a methodology to diagnose marine propeller shaft fatigue in operating conditions. The third part of the article is devoted to this issue