2020 - Repozytorium publikacji - Politechnika Gdańska

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Concrete-filled FRP tubular members in marine and bridge structures
- Marcin Abramski
2020
Concrete core of the concrete-filled tubes (CFTs) with circular cross-section is in the case of an axial compression subjected to a spatial state of compressive stresses. This state leads to enhancement in the concrete strength. The enhancement is utilized in Eurocode 4 design procedures for CFSTs (i.e. CFTs with tube made of steel). The structural design of CFFTs (i.e. CFTs with tube made of Fibre Reinforced Polymer - FRP) is normalized in LFRD Guide Specifications released by AASHTO in 2012. The mathematical model of confined concrete adopted in these design guidelines has also regard to the concrete strength enhancement. The differences between the both models of triaxially compressed concrete are discussed in the paper. The latter model was used in an author’s computer program developed to calculate the load-carrying capacity of 15 CFFT columns which were previously experimentally investigated in the axial and eccentric compression. The calculated and experimentally obtained capacities are compared. The auctorial program predicted the columns load-carrying capacity with a safety margin of 33% on average.
Conductivity, structure, and thermodynamics of Y2Ti2O7–Y3NbO7 solid solutions
- Piotr Winiarz
- Aleksandra Mielewczyk-Gryń
- Kristina Lilova
- Sebastian Wachowski
- Tamilarasan Subramani
- Mykola Abramchuk
- Ewa Dzik
- Alexandra Navrotsky
- Maria Gazda
2020 Pełny tekst DALTON TRANSACTIONS
The defect fluorite yttrium niobate Y3NbO7 and pyrochlore yttrium titanate Y2Ti2O7 solid solutions have been synthesized via a solid state synthesis route. The resulting stoichiometry of the oxides is Y2+xTi2−2xNbxO7, where x = 0 to x = 1. All of the samples were single-phase; however, for those with a predominant fluorite phase, a small amount of additional pyrochlore phase was detected. The volume of the solid solution unit cells linearly increases with increase in yttrium niobate content. The water uptake increases with (x) and the protonic defect concentration reaches almost 4.5 × 10−3 mol mol−1 at 300 °C. The calculated enthalpy of formation from oxides suggests strong stability for all of the compositions, with the values of enthalpy ranging from −84.6 to −114.3 kJ mol−1 . The total conductivity does not have a visible dependence on Y3NbO7 content. For each compound, the total conductivity is higher in wet air. Interestingly, for samples where x < 0.5, the ratio of conductivity in hydrogen to air increases with increasing temperature, while for x > 0.5, the trend is the opposite.
Conjugates of Ciprofloxacin and Levofloxacin with Cell-Penetrating Peptide Exhibit Antifungal Activity and Mammalian Cytotoxicity
- Natalia Ptaszyńska
- Katarzyna Gucwa
- Katarzyna Olkiewicz
- Mateusz Heldt
- Marcin Serocki
- Anna Stupak
- Dorota Martynow
- Dawid Dębowski
- Agata Gitlin-Domagalska
- Jan Lica
- Anna Łęgowska
- Sławomir Milewski
- Krzysztof Rolka
2020 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
Seven conjugates composed of well-known fluoroquinolone antibacterial agents, ciprofloxacin (CIP) or levofloxacin (LVX), and a cell-penetrating peptide transportan 10 (TP10-NH2) were synthesised. The drugs were covalently bound to the peptide via an amide bond, methylenecarbonyl moiety, or a disulfide bridge. Conjugation of fluoroquinolones to TP10-NH2 resulted in congeners demonstrating antifungal in vitro activity against human pathogenic yeasts of the Candida genus (MICs in the 6.25 – 100 μM range), whereas the components were poorly active. The antibacterial in vitro activity of most of the conjugates was lower than the activity of CIP or LVX, but the antibacterial effect of CIP-S-S-TP10-NH2 was similar to the mother fluoroquinolone. Additionally, for two representative CIP and LVX conjugates, a rapid bactericidal effect was shown. Compared to fluoroquinolones, TP10-NH2 and the majority of its conjugates generated a relatively low level of reactive oxygen species (ROS) in human embryonic kidney cells (HEK293) and human myeloid leukemia cells (HL-60). The conjugates exhibited cytotoxicity against three cell lines, HEK293, HepG2 (human liver cancer cell line), and LLC-PK1 (old male pig kidney cells), with IC50 values in the 10 – 100 μM range and hemolytic activity. The mammalian toxicity was due to the intrinsic cytoplasmic membrane disruption activity of TP10-NH2 since fluoroquinolones themselves were not cytotoxic. Nevertheless, the selectivity index values of the conjugates, both for the bacteria and human pathogenic yeasts, remained favourable.
Considerations about the applicability of the Reynolds equation for analyzing high-speed near field levitation phenomena
- Noël Brunetière
- Michał Wodtke
2020 Pełny tekst JOURNAL OF SOUND AND VIBRATION
equation for analyzing near field levitation (NFL) phenomena. Two separate approaches were developed, experimentally verified, and applied to meet the research objective. One was based on the Reynolds equation and the other was based on general conservation equations for fluid flow solved using computational fluid dynamic (CFD). Comparing the calculation results revealed that, for certain operating conditions, differences in the predicted system parameters appear. It was proven that both the Reynolds and Helmholtz numbers define border operating conditions for the applicability of the Reynolds equation to analyze NFL problems.
Constitutive Modelling of Knitted Abdominal Implants in Numerical Simulations of Repaired Hernia Mechanics
- Agnieszka Tomaszewska
- Daniil Reznikov
- Czesław Szymczak
- Izabela Lubowiecka
2020 Pełny tekst
The paper presents a numerical approach to describe mechanical behavior of anisotropic textile material, which is a selected abdominal prosthesis. Two constitutive nonlinear concepts are compared. In the first one the material is considered composed from two families of threads (dense net model) and in the second one the material is homogeneous but anisotropic (as proposed by Gassel, Ogden, Holzapfel). Parameters of both models are identified based on experimental tensile tests (uni-axial and bi-axial, simple and cyclic). The constitutive relations are applied in numerical membrane model of the prosthesis applied in the abdominal wall. Its mechanical responses to the pressure loading has been compared, also to deflection experimentally observed in physical model of the operated hernia of the same geometry. The authors find that both constitutive models properly describe the implant’s mechanics, but further studies are needed to possibly approach the outcome of hyperelastic anisotropic model to experimental results obtained for synthetic knit mesh
Constructing a Dataset of Speech Recordingswith Lombard Effect
- Dawid Weber
- Szymon Zaporowski
- Daniel Korzekwa
2020
Thepurpose of therecordings was to create a speech corpus based on the ISLEdataset, extended with video and Lombard speech. Selected from a set of 165sentences, 10, evaluatedas having thehighest possibility to occur in the context ofthe Lombard effect,were repeated in the presence of the so-called babble speech to obtain Lombard speech features. Altogether,15speakers were recorded, and speech parameterswere calculated and analyzed. First, a brief summary of the research related to the Lombard effect is given. Then, therecording studiocharacteristicsand the equipment utilizedfor recordings areshown.Examples of analyses are included,concerning both non-Lombard and Lombard speech. Finally, a recapitulation of experiments performedalong with further researchplans is given.The link to the data is also provided.
Consumerism in Poland – a fact or a myth?
- Anna Drapińska
2020
Purpose Consumerism, understood as excessive consumption, poses a vital problem in the world, and requires taking appropriate steps and actions in individual countries depending on the extent and nature of this phenomenon. The purpose of this paper is to examine the phenomenon of consumerism in Poland, with partial reference to other EU countries and to answer the question whether there is consumerism as such in Poland. Design/methodology/approach Data from secondary sources were used for the purpose of the paper. The study is based on statistical data analysis (Eurostat, Polish Statistical Main Office) and surveys of national experts, institutions and research agencies. The time span of the data observed extended from 2010 to 2018. The applied method can be defined as a descriptive statistics method with elements of quantitative analysis. Findings The study shows that the phenomenon of consumerism in Poland is not yet developed to the extent comparable to Western European countries. With the basic needs of the majority of average Polish households consuming the major part of their income, combined with the necessity to rationalize spending, which is forced by social and economic situation, consumers are more inclined to reasonably manage their resources. Polish consumers are still trying to catch up and meet their needs at a level similar to that in highly developed countries. Nevertheless, one can observe some symptoms of consumerist behaviour, e.g. spending on pleasure and entertainment prevails over saving, buying unnecessary things, or pleasure shopping. Originality/value Until now, the subject of consumerism in Poland was tackled very rarely and in a fragmentary way. No answer was given to the question whether there is consumerism in Poland and what is the level of its advancement. This paper is an attempt to identify this phenomenon based on available secondary sources. In addition it has been shown that statistics indicating the fifth place of Poland in Europe in terms of food waste are 'best estimates' mainly based on 2006 data from Eurostat and unfortunately no data were available from Poland.
Contact force network evolution in active earth pressure state of granular materials: photo‑elastic tests and DEM
- Leśniewska Danuta
- Michał Nitka
- Andrzej Tejchman-Konarzewski
- M. Pietrzak
2020 Pełny tekst GRANULAR MATTER
Artykuł omawia ewolucję sieci sił kontaktowych w materiałach granulowanych podczas quasi-statycznego stanu aktywnego. Doświadczenia foto sprężyste zostały wykonane dla kulek szklanych. Doświadczenia zostały symulowane stosując metodę elementów dyskretnych (DEM). Model DEM prawidłowo przewidział strukturę sił kontaktowych i ich wielkość, lokalizację odkształceń oraz obszary zmian fazowych.
Contamination of Arctic Lakes with Persistent Toxic PAH Substances in the NW Part of Wedel Jarlsberg Land (Bellsund, Svalbard)
- Sara Lehmann-konera
- Ruman Marek
- Łukasz Franczak
- Żaneta Polkowska
2020 Pełny tekst Water
The expansion of glacier‐free areas in polar regions favours the appearance of lakes in the non‐glaciated parts of glacier basins. This paper presents the differentiation of organic compound concentrations in fifty‐four Arctic lakes collected in four locations (Logne Valley, in the vicinity of the Scott, Renard and Antonia glaciers). We cover meteorological measurements, chemical analysis of sixteen dioxin‐like compounds (Polycyclic Aromatic Hydrocarbons (PAHs)), formaldehyde (HCHO), sum parameters of phenolic compounds (Σphenols) and dissolved organic carbon (DOC). The most contaminated with PAH compounds were lakes exposed to the influence of the Greenland Sea (Logne Valley lakes) and to the prevailing winds (Scott and Renard lakes). Interpretation of the PAH compounds results allowed for identification of pyrogenic sources as the main sources of PAH compounds in the year 2012. The highest levels of HCHO and Σphenols were observed for the Scott lakes, while the highest DOC levels were noted in Antonia lakes.
Contemporary architecture within the context of architectural education
- Agnieszka Malinowska
- Karolina Taraszkiewicz
2020 Pełny tekst World Transactions on Engineering and Technology Education
Analysed in this article are the diploma projects of students of architecture in European countries. The aim was to examine how students approach an important issue related to sustainable development, i.e. the integration of newly designed architecture into the existing historical, cultural and natural context. The rational use and protection of the environment requires the skilful shaping of urbanised space. Many changes in the surrounding space, which result from the work of architectural engineers, have a huge impact on the quality of this space. Special emphasis was placed on creating methods for educating future professional engineer architects to understand the need for the proper coexistence of newly designed urban and architectural solutions within the existing historical, cultural and natural context, as well as having the skills to create such solutions.
Contextual ontology for tonality assessment
- Wojciech Waloszek
- Nina Rizun
2020 Pełny tekst Procedia Computer Science
classification tasks. The discussion focuses on two important research hypotheses: (1) whether it is possible to construct such an ontology from a corpus of textual document, and (2) whether it is possible and beneficial to use inferencing from this ontology to support the process of sentiment classification. To support the first hypothesis we present a method of extraction of hierarchy of contexts from a set of textual documents and encoding this hierarchy into a multi-level contextual ontology. To support the second hypothesis, we present a method of reasoning from the ontology, and results of experimental verification, which show that use of this reasoning method can increase accuracy of sentiment classification for longer text documents
Control of nonlinear and linearized model of self-balancing electric motorcycle
- Adam Wonia
- Michał Wonia
- Robert Piotrowski
2020 Pełny tekst
Self-Balancing Electric Motorcycle (SBEM) is a dynamic and nonlinear electro-mechanical system. In this paper, the process of mathematical modelling and line-arization of SBEM is presented. The model of the control system in Matlab envi-ronment is implemented. The control system using the PID controller is designed. The operation of particular structures of the PID controller on the simulation model is compared. Due to simulation research, the most appropriate structure and parameters of the PID controller are chosen.
Convenient and Efficient Synthesis of Functionalized 2-Sulfenylindoles
- Justyna Doroszuk
- Mateusz Musiejuk
- Bartosz Jędrzejewski
- Juliusz Walczak
- Dariusz Witt
2020 Pełny tekst Materials
A simple, efficient, and practical sulfenylation at the C2 position of N-tosylindoles under mild conditions was developed. The designed transformation is based on the reaction of N-tosylindoles with BuLi and S-alkyl, and S-aryl phosphorodithioates or thiotosylates to produce 2-sulfenylindoles in moderate to high yields. The presence of additional hydroxy, carboxy, or amino functionalities did not disturb the formation of products
Convergence of Monte Carlo algorithm for solving integral equations in light scattering simulations
- Maciej Kraszewski
- Jerzy Pluciński
2020 Pełny tekst OPTICA APPLICATA
The light scattering process can be modeled mathematically using the Fredholm integral equation. This equation is usually solved after its discretization and transformation into the system of algebraic equations. Volume integral equations can be also solved without discretization using the Monte Carlo (MC) algorithm, but its application to the light scattering simulations has not been sufficiently studied. Here we present implementation of this algorithm for one- and three-dimensional light scattering computations and discuss its applicability in this field. We show that the MC algorithm can provide valid and accurate results but, due to its convergence properties, it might be difficult to apply for problems with large volumes or refractive indices of scattering objects.
Coordination complexes of Mn(II), Co(II), Ni(II), Zn(II) and Cd(II) with histaminol – Crystal structures and formation constants in aqueous solution
- Piotr Maślewski
- Dariusz Wyrzykowski
- Weronika Kentner
- Anna Ciborska
- Anna Dołęga
2020 POLYHEDRON
Stability constants were determined for a series of coordination complexes of Mn(II), Co(II), Ni(II), Zn(II) and Cd(II) with histaminol in aqueous solution. The tendency of histaminol to form chelate complexes has been confirmed by the isolation of several complex species in the monocrystalline form and determination of their molecular structures.
Copolymerization of Styrene and Pentadecylphenylmethacrylate (PDPMA): Synthesis, Characterization, Thermomechanical and Adhesion Properties
- Tomy Muringayil
- Sumi Murali Nair
- Suresh Kattimuttathu Ittara
- Józef Haponiuk
- Sabu Thomas
2020 Pełny tekst Polymers
The copolymerization of styrene (St) with a bioderived monomer, pentadecylphenylmethacrylate (PDPMA), via atom transfer radical polymerization (ATRP) was studied in this work.The copolymerization reactivity ratio was calculated using the composition data obtained from1HNMR spectroscopy, applying Kelen-Tudos and Finemann-Ross methods. The reactivity ratio of styrene (r1=0.93) and PDPMA (r2=0.05) suggested random copolymerization of the two monomers with alternation. The copolymerization conversion increased with increasing PDPMA concentrationof the feed, upto 70 wt % PDPMA, but decreased thereafter. The molecular weight determined by gel permeation chromatography was lower than the theoretical values and the polydispersity increased from 1.32 to 2.19, with increasing PDPMA content in the feed. The influence of styrene content on the glass transition and thermal decomposition behavior of the copolymers was studied bydifferential scanning calorimetry (DSC) and thermogravimetric analysis, respectively. Morphologicalcharacterization by transmission electron microscopy (TEM) revealed a phase separated soft core-hardshell type structure. The complex viscosity and adhesion properties like peel strength and lap shear strength of the copolymer on different substrates increased with increasing styrene content
Corporate Entrepreneurship: A Literature Review and Future Research Perspectives
- Magdalena Popowska
2020 Pełny tekst International Journal of Contemporary Management
Background. Nowadays, corporate entrepreneurship (CE) is perceived as an essential approach to boost the innovation and creativity within existing organizations for achieving higher opportunities in the market. This paper examines this concept, which has been largely discussed in the Anglo-Saxon world over the last thirty years. Like for many other phenomena, also in case of CE, this discussion has provided numerous conceptualizations, and consequently, there is not one unique definition of CE. In this respect, the search for an appropriate basis for understanding and describing the phenomenon of CE engenders a challenging issue for entrepreneurship researchers. Research aims. This paper aims at creating a large platform for understanding the concept of CE by means of a clarification effort through the review of the most important papers in this field and identification of the existing research gaps. Methodology. Systematic literature survey is the applied methodology. EBSCO and Taylor & Francis database were used as a source for the sampling process. Key findings. The analysis does acknowledge the need for more qualitative and rigorous research in this field and brings several recommendations for the future studies. The main conclusions also do urge for a more diversified research in terms of the sectors discussed, as the biggest gap identified is in the services sector. There is also a need for a more structured classification of the measures, depending on the real research focus: CE antecedents or outcomes.
Corporate social responsibility practices incomes and outcomes: Stakeholders' pressure, culture, employee commitment, corporate reputation, and brand performance. A Polish–German cross‐country study
- Rafał Kowalczyk
- Wioleta Kucharska
2020 Pełny tekst Corporate Social Responsibility and Environmental Management
This study aims to compare employee perception of corporate social responsibility (CSR) practice incomes and outcomes in the construction industry in Poland and Germany. It proposes a model that examines the influence of stakeholder pressure, culture, and CSR practices on company brand performance, reputation, and employee identification. The findings suggest that the structure of relationships varies for project‐managed construction companies in a developed country such as Germany and a rapidly transformed Poland. The structural equation modeling method was adopted to analyze the differences between the structures of relationships using AMOS and Process software. The key finding reveals that stakeholder pressure can lead to consistent CSR‐oriented system in the business environment. This study was first conducted in 2018 and then replicated in 2019 to confirm the results with 1,674 cases. The novelty essence is the comparison of the Polish and German structure of CSR practice incomes and outcomes related to employee perception.
Correction of determined coordinates of railway tracks in mobile satellite measurements
- Andrzej Wilk
- Cezary Specht
- Krzysztof Karwowski
- Władysław Koc
- Jacek Skibicki
- Krzysztof Czaplewski
- Piotr Chrostowski
- Paweł Dąbrowski
- Sławomir Grulkowski
- Sławomir Judek
- Mariusz Specht
- Jacek Szmagliński
2020 Pełny tekst Diagnostyka
This article examines one of the basic issues related to the technique of mobile satellite measurements in railway tracks. This problem concerns the correction of the determined coordinates of the track centerline. The need to perform this operation results from the GNSS receivers positioning at a certain height above the level of the existing track axis, leading to longitudinal and lateral shifts of antennas. The key problem here is the determination of the local horizontal coordinate system in each measured position. For the analysis, the authors defined the directional baseline vector of the measuring platform on the basis of positions given by two satellite antennas, positioned over the pivots of its bogies. This work presents the procedure for determining the corrections values
Correlation between partial inhibition of hydrogen evolution using thiourea and catalytic activity of AB5-type hydrogen storage alloy towards borohydride electrooxidation
- Małgorzata Graś
- Jarosław Wojciechowski
- Katarzyna Lota
- Tomasz Buchwald
- Jacek Ryl
- Grzegorz Lota
2020 Pełny tekst JOURNAL OF ALLOYS AND COMPOUNDS
Direct borohydride fuel cells (DBFCs) are devices which directly convert the chemical energy stored in the borohydride ion and oxidant into electrical energy as a result of redox reactions. Unfortunately, a significant amount of fuel is lost as a result of the undesirable hydrolysis reaction. The selection of an efficient borohydride hydrolysis inhibitor requires detailed knowledge regarding the interaction mechanism between the inhibitor molecule and electrode surface. In this study, various amounts of thiourea additives (0.011–1.600 mM) were tested to select the best fuel composition for DBFC application. When AB5-type anode was used, only partial inhibition of sodium borohydride hydrolysis was a desirable phenomenon. Partially released hydrogen results in the improvement of catalytic properties of the alloy. The addition of 0.016 mM thiourea does not inhibit the oxidation of borohydride, on the contrary, it increases the practical capacity from 27% to 41% of the theoretical value. Moreover, we indicate that the addition of thiourea prevents corrosion as well as degradation of the electrode surface. Pressure measurements confirmed the effectiveness of thiourea in relation to hydrogen evolution, while X-ray photoelectron spectroscopy and Raman spectroscopy revealed that the electrode surface was not poisoned.