2020 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2020

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CENTRUM w systemie STRADAR – funkcje, architektura i realizacja
- Marek Blok
- Sylwester Kaczmarek
- Magdalena Młynarczuk
2020 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
System STRADAR jest rozwiązaniem umożliwiającym utworzenie infrastruktury komunikacyjno-teleinformatycznej przeznaczonej dla Morskiego Oddziału Straży Granicznej. Artykuł ten jest kolejną z cyklu publikacji opisujących architekturę i rozwiązanie systemu i dotyczy jego centralnego elementu, jakim jest CENTRUM. Przedstawiono i opisano funkcje, architekturę i realizację oprogramowania CENTRUM, które może być zainstalowane na dowolnym serwerze ze środowiskiem Linux. Oprogramowanie to przeszło pozytywnie testy akceptacyjne w ramach zrealizowanego prototypu systemu.
Ceramic composites for single-layer fuel cells
- Piotr Winiarz
- Tadeusz Miruszewski
- Sebastian Wachowski
- Kacper Dzierzgowski
- Iga Szpunar
- Krzysztof Zagórski
- Aleksandra Mielewczyk-Gryń
- Maria Gazda
2020 Pełny tekst SOLID STATE SCIENCES
Composite materials consisting of acceptor doped lanthanum orthoniobate electrolyte phase (La0.98Ca0.02NbO4) and Li2O:NiO:ZnO semiconducting phase were synthesized. The precursor powder of La0.98Ca0.02NbO4 was prepared in nanocrystalline (mechanosynthesis) and microcrystalline (solid-state synthesis) form. The composite can be applied in a single-layer fuel cell, because of the presence of two phases acting as an anode and a cathode simultaneously. X-ray diffraction data show that the materials consist of two expected phases. Scanning Electron Microscope images, with Energy Dispersive X-Ray analysis show that La0.98Ca0.02NbO4 as well as Li2O:NiO:ZnO are mixed together in the volume of the material. Open circuit voltage both for nano- and microcrystalline composite do not exceed 0.8 V. The single-layer fuel cell is degrading upon time and the voltage drop is observed. The processes of ZnO reduction and Zn diffusion and evaporation as responsible for cell degradation are discussed.
Certified domination
- Magda Dettlaff
- Magdalena Lemańska
- Jerzy Topp
- Radosław Ziemann
- Paweł Żyliński
2020 Pełny tekst AKCE International Journal of Graphs and Combinatorics
Imagine that we are given a set D of officials and a set W of civils. For each civil x ∈ W, there must be an official v ∈ D that can serve x, and whenever any such v is serving x, there must also be another civil w ∈ W that observes v, that is, w may act as a kind of witness, to avoid any abuse from v. What is the minimum number of officials to guarantee such a service, assuming a given social network? In this paper, we introduce the concept of certified domination that models the aforementioned problem. Specifically, a dominating set D of a graph G = (VG, EG) is said to be certified if every vertex in D has either zero or at least two neighbours in VG \ D. The cardinality of a minimum certified dominating set in G is called the certified domination number of G. Herein, we present the exact values of the certified domination number for some classes of graphs as well as provide some upper bounds on this parameter for arbitrary graphs. We then characterise a wide class of graphs with equal domination and certified domination numbers and characterise graphs with large values of certified domination numbers. Next, we examine the effects on the certified domination number when the graph is modified by deleting/adding an edge or a vertex. We also provide Nordhaus–Gaddum type inequalities for the certified domination number.
Changes in conditions of acoustic wave propagation in the Gdansk deep as an effect of climate changes in the Baltic Sea region
- Grażyna Grelowska
- Eugeniusz Kozaczka
2020 Pełny tekst MARINE POLLUTION BULLETIN
The article presents the results from a research project investigating acoustic climate changes in the Gdansk Deep based on data extending from 1902 to 2019. This part of the southern Gotland Basin, is rarely discussed in the scientific literature. The speed of sound in the seawater is a function of temperature, salinity, and depth. In such shallow sea as Baltic Sea, the impact of depth is not substantial. The other two factors shape the hydroacoustic conditions. In the upper layer of seawater, the dominating factor is heat exchange at the water-atmosphere interface. The observed climate warming is reflected in the water temperature rise, which results in an increased speed of sound in the upper water layer. After years of sporadic salty inflows from the North Sea, the frequency of the phenomenon has increased since 2014. As a result, the salinity at the bottom exceeds values typical for that area.
Changes in the structure of Armenia’s labour resources between 1993 and 2020
- Krystyna Gomółka
- Karol Flisikowski
2020 Economic Annals-XXI
The article characterises the structure of Armenia’s labour resources in the period between1993 and 2020. It aims to assess the changes on the Armenian labour market by means of a deductive analysis of historical data and observation of changes in the structure of resources based on generally available macroeconomic data. The authors evaluate these processes against the background of demographic and economic changes, by presenting and describing statistical data. Variables such as data on the economic situation of the country (income capita, inflation rate and unemployment), demographic data (employment structure, population structure, migration) are used for the analysis. The analysis demonstrates that the COVID-19 pandemic and the Nagorno-Karabakh conflict led to an economic downturn in Armenia, with GDP per capita falling, and inflation rising. A more rapid decrease in employment could be observed in 2020, manifesting itself in a declining number of employees, selfemployed and entrepreneurs. A much more significant drop in employment was observed in urban areas than in the countryside, although the total number of agricultural workers in Armenia decreased compared to the 1990s. The governmental measures and programmes aimed at protecting jobs and businesses and mitigating the effects of the COVID-19 pandemic proved to be insufficient. In 2020, fewer citizens emigrated from Armenia as a result of the state of the emergency maintained from March to June 2020 and the closing of state borders.
Changes of Conformation in Albumin with Temperature by Molecular Dynamics Simulations
- Piotr Weber
- Piotr Bełdowski
- Krzysztof Domino
- Damian Ledziński
- Adam Gadomski
2020 Pełny tekst ENTROPY
This work presents the analysis of the conformation of albumin in the temperature range of 300K – 312K, i.e., in the physiological range. Using molecular dynamics simulations, we calculate values of the backbone and dihedral angles for this molecule. We analyze the global dynamic properties of albumin treated as a chain. In this range of temperature, we study parameters of the molecule and the conformational entropy derived from two angles that reflect global dynamics in the conformational space. A thorough rationalization, based on the scaling theory, for the subdiffusion Flory–De Gennes type exponent of 0.4 unfolds in conjunction with picking up the most appreciable fluctuations of the corresponding statistical-test parameter. These fluctuations coincide adequately with entropy fluctuations, namely the oscillations out of thermodynamic equilibrium. Using Fisher’s test, we investigate the conformational entropy over time and suggest its oscillatory properties in the corresponding time domain. Using the Kruscal–Wallis test, we also analyze differences between the root mean square displacement of a molecule at various temperatures. Here we show that its values in the range of 306K – 309K are different than in another temperature. Using the Kullback–Leibler theory, we investigate differences between the distribution of the root mean square displacement for each temperature and time window.
Characterization of Defects Inside the Cable Dielectric With Partial Discharge Modeling
- Khan Qasim
- S. Shady Refaat
- Haitham Abu-Rub
- A. Hamid Toliyat
- Marek Olesz
- Ahmad Darwish
2020 IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
The continuous monitoring of power system devices is an important step toward keeping such capital assets safe. Partial discharge (PD)-based measurement tools provide a reliable and accurate condition assessment of power system insulations. It is very common that voids or cavities exist in every solid dielectric insulation medium. In this article, different voids are modeled and analyzed using an advanced finite element (FE)-based computational algorithm. The proposed approach can be used to measure PD in cavities and voids regardless of their shape and size. The frequentative scripting approach with finite element modeling (FEM) provides the results which satisfy all PD conditions. PD behavior has been studied and analyzed through PD statistical features obtained from the simulated PD signal. A comparative study between simulated and experimental results is also performed to validate the accuracy of the proposed modeling approach. To further improve the accuracy of the model, the influence and optimization of certain free parameters required for modeling has been carried out. The article shows how PD is greatly influenced by the shape and size of voids in dielectric insulators. The research realized in this article further provides the PD statistical features and its variation with respect to void shape and size. These features are utilized for the assessment of insulation quality. The variation in PD parameters with respect to voltage level is also presented and discussed.
Characterization of the Functionally Graded Shear Modulus of a Half-Space
- Vladimir Zelentsov
- Polina Lapina
- Boris Mitrin
- Victor Eremeev
2020 Pełny tekst Mathematics
In this article, a method is proposed for determining parameters of the exponentialy varying shear modulus of a functionally graded half-space. The method is based on the analytical solution of the problem of pure shear of an elastic functionally graded half-space by a strip punch. The half-space has the depth-wise exponential variation of its shear modulus, whose parameters are to be determined. The problem is reduced to an integral equation that is then solved by asymptotic methods. The analytical relations for contact stress under the punch, displacement of the free surface outside the contact area and other characteristics of the problem are studied with respect to the shear modulus parameters. The parameters of the functionally graded half-space shear modulus are determined (a) from the coincidence of theoretical and experimental values of contact stresses under the punch and from the coincidence of forces acting on the punch, or (b) from the coincidence of theoretical and experimental values of displacement of the free surface of the half-space outside the contact and coincidence of forces acting on the punch, or (c) from other conditions. The transcendental equations for determination of the shear modulus parameters in cases (a) and (b) are given. By adjusting the parameters of the shear modulus variation, the regions of “approximate-homogeneous” state in the functionally graded half-space are developed.
CHARACTERIZATION STUDY ON MECHANICAL PROPERTIES OF POLYESTER COATED FABRIC
- Andrzej Ambroziak
2020 Pełny tekst Archives of Civil Engineering
The scope of the paper is to determine the mechanical properties of the Precontraint 1302 polyester coated fabric under uniaxial and biaxial tensile tests. The results are compared for Precontraint 1302 fabric and other types of coated fabrics. The author applied an orthotropic model and a dense net model to reflect the polyester coated fabric performance under uniaxial and biaxial tensile tests. Material parameters are specified for both constitutive models. In order to observe the variation of immediate mechanical properties, the biaxial cyclic tests are performed for different load ratios. During uniaxial and 1:1 biaxial tensile tests it is barely observable to recognize warp or weft directions on the stress-strain curves. Load history acts strongly on the mechanical properties of the Precontraint 1302 polyester fabrics. The cyclic loads cause variation of immediate longitudinal stiffness with a comparison of values determined for unloaded coated fabrics. The paper can provide scientists, engineers, and designers an experimental and theoretical basis in the field of polyester coated fabrics.
Chemia, a ludzki mózg
- Bartłomiej Cieślik
2020 Pełny tekst
Wiele substancji chemicznych ma udowodniony wpływ na funkcjonowanie mózgu. Część z nich, jak np. hormony, produkowane są przez sam mózg. Mogą one decydować o wielu naszych zachowaniach oraz, do pewnego stopnia, wpływać na podejmowanie decyzji. Istnieją również substancje wpływające na funkcjonowanie mózgu, które mogą być dostarczane z zewnątrz. Mogą mieć one zarówno pozytywny jak i negatywny wpływ na jego funkcjonowanie. Należy zdawać sobie sprawę, że przyjmowanie różnego rodzaju używek, stymulantów, czy nawet niektórych suplementów diety może mieć poważne konsekwencja. Świadome przyjmowanie ksenobiotyków jest zatem kluczowe w zachowaniu „higieny” naszego mózgu.
Chemometrics for Selection, Prediction, and Classification of Sustainable Solutions for Green Chemistry—A Review
- Marta Bystrzanowska
- Marek Tobiszewski
2020 Pełny tekst Symmetry-Basel
In this review, we present the applications of chemometric techniques for green and sustainable chemistry. The techniques, such as cluster analysis, principal component analysis, artificial neural networks, and multivariate ranking techniques, are applied for dealing with missing data, grouping or classification purposes, selection of green material, or processes. The areas of application are mainly finding sustainable solutions in terms of solvents, reagents, processes, or conditions of processes. Another important area is filling the data gaps in datasets to more fully characterize sustainable options. It is significant as many experiments are avoided, and the results are obtained with good approximation. Multivariate statistics are tools that support the application of quantitative structure–property relationships, a widely applied technique in green chemistry.
Chestnut-Derived Activated Carbon as a Prospective Material for Energy Storage
- Katarzyna Januszewicz
- Anita Cymann-Sachajdak
- Paweł Kazimierski
- Marek Klein
- Justyna Łuczak
- Monika Wilamowska-Zawłocka
2020 Pełny tekst Materials
In this work, we present the preparation and characterization of biomass-derived activatedcarbon (AC) in view of its application as electrode material for electrochemical capacitors. Porouscarbons are prepared by pyrolysis of chestnut seeds and subsequent activation of the obtainedbiochar. We investigate here two activation methods, namely, physical by CO2and chemical usingKOH. Morphology, structure and specific surface area (SSA) of synthesized activated carbons areinvestigated by Brunauer-Emmett-Teller (BET) technique and scanning electron microscopy (SEM).Electrochemical studies show a clear dependence between the activation method (influencing porosityand SSA of AC) and electric capacitance values as well as rate capability of investigated electrodes.It is shown that well-developed porosity and high surface area, achieved by the chemical activationprocess, result in outstanding electrochemical performance of the chestnut-derived porous carbons.
Child-Robot Interaction Studies During COVID-19 Pandemic
- Pinar Uluer
- Hatice Kose
- Agnieszka Landowska
- Tatjana Zorcec
- Ben Robins
- Duygun Erol Barkana
2020
The coronavirus disease (COVID-19) pandemic affected our lives deeply, just like everyone else, the children also suffered from the restrictions due to COVID-19 affecting their education and social interactions with others, being restricted from play areas and schools for a long time. Although social robots provide a promising solution to support children in their education, healthcare, and social interaction with others, the precautions due to COVID-19 also introduced new constraints in social robotics research. In this paper, we will discuss the benefits and challenges encountered in child-robot interaction due to COVID-19 based on two user studies. The first study involves children with hearing disabilities, and Pepper humanoid robot to support their audiometry tests. The second study includes the child-sized humanoid robot Kaspar and interaction games with children with autism spectrum disorder (ASD).
Chitin nanowhiskers from shrimp shell waste as green filler in acrylonitrile-butadiene rubber: Processing and performance properties
- Midhun Dominic C.D.
- Rani Joseph
- P.m. Sabura Begum
- Aswathy Raghunandanan
- Nelwin T. Vackkachan
- Dileep Padmanabhan
- Krzysztof Formela
2020 CARBOHYDRATE POLYMERS
In this work, chitin nanowhiskers with high crystallinity index were obtained from shrimp shells waste using acid hydrolysis method and then comprehensively characterized. Subsequently, the impact of chitin nanowhisker content on processing and performance of acrylonitrile-butadiene rubber based nanocomposites was evaluated. The results showed that the addition of chitin nanowhiskers increased tensile strength and tear strength of nanocomposites by 116% and 54%, which was related to suitable dispersion of chitin nanowhiskers in matrix. Reinforcing effect of chitin nanowhiskers in acrylonitrile-butadiene rubber was also confirmed by Wolff activity coefficient, glass transition temperature and equilibrium swelling measurements. Moreover, it was found that higher content chitin nanowhiskers significantly improve the thermal stability of studied nanocomposites. The incorporation of chitin nanowhiskers resulted in increase of 74 °C for onset degradation temperature. This work confirmed that shrimp shell waste can be upcycled into chitin nanowhiskers - promising green filler in NBR for high-performance elastomeric applications.
Chloroacridine derivatives as potential anticancer agents which may act as tricarboxylic acid cycle enzyme inhibitors
- Miroslawa Cichorek
- Anna Ronowska
- Krystyna Dzierzbicka
- Monika Gensicka-Kowalewska
- Milena Deptuła
- Iwona Pelikant-Malecka
2020 Pełny tekst BIOMEDICINE & PHARMACOTHERAPY
The chloroacridines affect biological forms of melanoma in different ways. Amelanotic (Ab) melanoma (with inhibited melanogenesis and higher malignancy) was particularly sensitive to the action of the chloroacridines. The Ab melanoma cells died through apoptosis and through death without caspase activation. Diminished activity of TAC enzymes was noticed among Ab melanoma cells together with ATP/NAD depletion, especially in the case of 1b. Our data show that the biological forms of the tumors responded to 1a and its 4-methylated analog in different ways. 1a and 1b could be inducers of regulated melanoma cell death, especially the amelanotic form. Although the mechanism of the cell death is not fully understood, 1b may act by interfering with the TAC enzymes and blocking specific pathways leading to tumor growth. This could encourage further investigation of its anticancer activity, especially against the amelanotic form of melanoma.
Choosing Exploration Process Path in Data Mining Processes for Complex Internet Objects
- Teresa Zawadzka
- Wojciech Waloszek
2020 Advances in Intelligent Systems and Computing
We present an experimental case study of a novel and original framework for classifying aggregate objects, i.e. objects that consist of other objects. The features of the aggregated objects are converted into the features of aggregate ones, by use of aggregate functions. The choice of the functions, along with the specific method of classification can be automated by choosing of one of several process paths, and different paths can be picked for different parts of the domain. The results are encouraging and show that our approach allowing for automated choice, can be beneficial for the data mining results.
Choosing Exploration Process Path in Data Mining Processes for Complex Internet Objects
- Teresa Zawadzka
- Wojciech Waloszek
2020
We present an experimental case study of a novel and original framework for classifying aggregate objects, i.e. objects that consist of other objects. The features of the aggregated objects are converted into the features of aggregate ones, by use of aggregate functions. The choice of the functions, along with the specific method of classification can be automated by choosing of one of several process paths, and different paths can be picked for different parts of the domain. The results are encouraging and show that our approach allowing for automated choice, can be beneficial for the data mining results.
Chór wirtualny
- Mariusz Mróz
- Bartłomiej Mróz
2020
Wiosna roku 2020 została zapisana emocjami, które należy zaliczać do tych niepożądanych. Praca on-line stała się jedyną możliwą formą pracy z zespołem. Prekursorem pomysłu wirtualnego chóru był amerykański kompozytor i dyrygent Eric Whitacre. Eric wybrał do wykonania przez chór wirtualny utwory posiadające wspólne cechy. Kolejnym poruszanym zagadnieniem jest stworzenie przestrzennego dźwięku. Technologia na której opiera się dźwięk przestrzenny nazywana jest ambisonią. Niewątpliwe walory chórów wirtualnych, i ich możliwości twórcze są wartością kultury XXI wieku. Koncert w realnym świecie jest żywy, kreuje dzieło muzyczne jedynie „tu i teraz”. Ubarwia emocjami wszystkich uczestników koncertu w danym miejscu i czasie. Wirtualna rzeczywistość może być piękna, jednak przeżywanie czegoś wyjątkowego zawsze wiąże się z koniecznością przebywania w centrum wydarzeń.
Chromatic cost coloring of weighted bipartite graphs
- Tytus Pikies
- Marek Kubale
2020 APPLIED MATHEMATICS AND COMPUTATION
Given a graph G and a sequence of color costs C, the Cost Coloring optimization problem consists in finding a coloring of G with the smallest total cost with respect to C. We present an analysis of this problem with respect to weighted bipartite graphs. We specify for which finite sequences of color costs the problem is NP-hard and we present an exact polynomial algorithm for the other finite sequences. These results are then extended to a substantial class of infinite sequences. We show that these results on both types of sequences partially transfer to unweighted bipartite graphs.
Ciprofloxacin-modified degradable hybrid polyurethane-polylactide porous scaffolds developed for potential use as an antibacterial scaffold for regeneration of skin
- Iga Carayon
- Agata Terebieniec
- Marcin Łapiński
- Natalia Filipowicz
- Justyna Kucińska-Lipka
2020 Pełny tekst Polymers
The aim of the performed study was to fabricate an antibacterial and degradable scaffold that may be used in the field of skin regeneration. To reach the degradation criterion for the biocompatible polyurethane (PUR), obtained by using amorphous α,ω-dihydroxy(ethylene-butylene adipate) macrodiol (PEBA), was used and processed with so-called “fast-degradable” polymer polylactide (PLA) (5 or 10 wt %). To meet the antibacterial requirement obtained, hybrid PUR-PLA scaffolds (HPPS) were modified with ciprofloxacin (Cipro) (2 or 5 wt %) and the fluoroquinolone antibiotic inhibiting growth of bacteria, such as Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, which are the main causes of wound infections. Performed studies showed that Cipro-modified HPPS, obtained by using 5% of PLA, possess suitable mechanical characteristics, morphology, degradation rates, and demanded antimicrobial properties to be further developed as potential scaffolds for skin tissue engineering.