2018 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2018

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On domination multisubdivision number of unicyclic graphs
- Joanna Raczek
2018 Pełny tekst Opuscula Mathematica
The paper continues the interesting study of the domination subdivision number and the domination multisubdivision number. On the basis of the constructive characterization of the trees with the domination subdivision number equal to 3 given in [H. Aram, S.M. Sheikholeslami, O. Favaron, Domination subdivision number of trees, Discrete Math. 309 (2009), 622–628], we constructively characterize all connected unicyclic graphs with the domination multisubdivision number equal to 3. We end with further questions and open problems.
On incidence coloring of coloring of complete multipartite and semicubic bipartite graphs
- Robert Janczewski
- Anna Małafiejska
- Michał Małafiejski
2018 Pełny tekst Discussiones Mathematicae Graph Theory
In the paper, we show that the incidence chromatic number of a complete k-partite graph is at most ∆+2 (i.e., proving the incidence coloring conjecture for these graphs) and it is equal to ∆+1 if and only if the smallest part has only one vertex.
On low-fidelity models for variable-fidelity simulation-driven design optimization of compact wideband antennas
- Sławomir Kozieł
- Sigmar Unnsteinsson
- Adrian Bekasiewicz
2018 Pełny tekst
The paper addresses simulation-driven design optimization of compact antennas involving variable-fidelity electromagnetic (EM) simulation models. Comprehensive investigations are carried out concerning selection of the coarse model discretization density. The effects of the low-fidelity model setup on the reliability and computational complexity of the optimization process are determined using a benchmark set of three ultra-wideband antennas designed for the best matching and for the minimum size. The optimization algorithm of choice is trust-region gradient search with low-fidelity model correction realized through frequency scaling and multiplicative output space mapping. The results indicate that appropriate low-fidelity model setup can be assessed using a correlation analysis based on the selected characteristic points of the antenna responses and sparsely allocated test designs, and the results are consistent across the considered benchmark set.
On phase equilibrium of an elastic liquid shell with wedge disclination
- Victor Eremeev
- Violetta Konopińska-Zmysłowska
2018
Based on the six-parameter shell theory we consider the phase equilibrium of a two-phase liquid membrane containing a wedge disclination. The considered problems are related to modelling of phase transitions in biological or lipid membranes. In order to capture the membrane behaviour we consider a special case of elastic shells which energy is invariant under major transformations of a reference configuration and can be treated as an two-dimensional elastic micropolar fluid which can resist bending deformations. Based on variational approach we formulate the equilibrium conditions at a phase interface. As an example, a two-phase state is analysed in the vicinity of a wedge disclination.
On the application of magnetoelastic properties measureme nts for plastic level determination in martensitic steels
- Leszek Piotrowski
- Marek Chmielewski
- Zbigniew Kowalewski
2018 Pełny tekst Journal of Electrical Engineering
The change in the dislocation density, induced by plastic deformation, influences strongly the magnetic domain structure inside the material. Being so, classic parameters, like the coercivity or magnetic permeability, can be a good measure of the deformation level, yet their reliable determination in a non-destructive way in industrial environment is problematic. The magnetoacoustic emission (MAE) which results from the non-180 degree domain walls (DW) movement in materials with non-zero magnetostriction can be used as an alternative. The intensity of the MAE signal changes strongly as a result of plastic deformation for both tensile and compressive deformation. It is however possible to discern those cases by analysing the changes in the shape of the MAE signal envelopes. The set of the martensitic steel samples (P91) deformed up to 10% (for both tension and compression) was investigated. Due to geometrical limitations imposed by the special mounting system, enabling compression without buckling, the sample had the shape resulting in low signal to noise (S/N) ratio. Being so the optimization of FFT filtering and wavelet analysis was performed in order to improve sensitivity of the proposed method of deformation level determination.
On the broadband behaviour of planar elliptical dipole-modal approach
- Włodzimierz Zieniutycz
- Mariusz Pergoł
2018
Broadband behavior of planar elliptical dipole structure is analyzed using Illuminatin Modes (IM) approach. The current on patch has been expanded in series of eigenfunctions in form of Mathieu radial and angular functions. The frequency behavior of current distributions and related powers have been discussed to explain the mechanism of broadband operation of the dipole. Different behavior of radiations patterns in wide frequency range have been also discussed and compared to the dipole model simulated in ADS MOMEMNTUM environment.
On the Disaster Resiliency within the Context of 5G Networks : The RECODIS Experience
- Christian Esposito
- Antonios Gouglidis
- David Hutchison
- Andrei Gurtov
- Bjarne Helvik
- Poul Heegaard
- Gianluca Rizzo
- Jacek Rak
2018
Network communications and the Internet pervade our daily activities so deeply that we strongly depend on the availability and quality of the services they provide. For this reason, natural and technological disasters, by affecting network and service availability, have a potentially huge impact on our daily lives. Ensuring adequate levels of resiliency is hence a key issue that future network paradigms, such as 5G, need to address. This paper provides an overview of the main avenues of research on this topic within the context of the RECODIS COST Action.
On the influence of the acceleration recording time on the calculation of impact severity indexes
- Łukasz Pachocki
- Dawid Bruski
- Jacek Chróścielewski
- Krzysztof Wilde
- Wojciech Witkowski
2018 Pełny tekst MATEC Web of Conferences
The paper concerns with the analysis of normative requirements pertaining to experimental setup of a crash test and its numerical modelling. An overview of parameters describing the collision of a vehicle with a road restraining system is presented. A short description of a concrete road safety barrier is presented. A brief description of numerical modelling procedures for crash tests is given as well. The parametric influence analysis is performed of the acceleration recording time on various crash test functionality parameters The simulations are carried out using LS-DYNA finite element code with a solver version R.8.1
On the material symmetry group for micromorphic media with applications to granular materials
- Victor Eremeev
2018 Pełny tekst MECHANICS RESEARCH COMMUNICATIONS
Within the framework of the theory of nonlinear elastic micromorphic continua we introduce the new definition of the local material symmetry group. The group consists of ordered triples of second- and third-order tensors describing such changes of a reference placement that cannot be recognized with any experiment. Using the definition we characterize the micromorphic isotropic media, micromorphic fluids, solids and special intermediate cases called micromorphic subfluids or micromorphic liquid crystals. We demonstrate that some typical behaviour of such complex media as granular materials can be described within the micromorphic subfluids mechanics.
On the Nonlinear Effects of Magnetoacoustic Perturbations in Optically Thin Quasi-Isentropic Plasmas
- Anna Perelomova
- Filip Ratkowski
2018 Pełny tekst ACTA PHYSICA POLONICA A
Nonlinear effects of planar magnetosound perturbations in a plasma are discussed. Plasma is non-adiabatic due to optically thin radiation and external heating. For these reasons, thermal instability of a plasma may appear which makes it acoustically active. The plasma is assumed to be initially homogeneous ideal gas with infinite electrical conductivity permeated by a straight magnetic field which is orthogonal to the trajectories of gas particles. The instantaneous dynamic equations which describe nonlinear effects of intense sound in quasi-isentropic plasma, are derived. Nonlinear interaction of periodic and aperiodic magnetoacoustic perturbations with the non-wave modes, are discussed. The conclusions concern dissipative or active behavior of magnetoacoustic perturbations which is determined by the kind of the heating-cooling function.
On the peculiarities of anti-plane surface waves propagation for media with microstructured coating
- Victor Eremeev
2018 Pełny tekst MATEC Web of Conferences
We discuss new type of surface waves which exist in elastic media with surface energy. Here we present the model of a coating made of polymeric brush. From the physical point of view the considered model of surface elasticity describes a highly anisotropic surface coating. Here the surface energy model could be treated as 2D reduced strain gradient continuum as surface strain energy depends on few second spatial derivatives of displacements. From the mechanical point of view the proposed model relates to 2D coating made of long fibers undergoing stretching and bending deformations. We consider here anti-plane surface waves. The dispersion relation is derived and its dependence on the material parameters is analysed.
On the relationship between the structural and volumetric properties of solvated metal ions in O-donor solvents using new structural data in amide solvents
- Daniel Lundberg
- Dorota Warmińska
- Anna Fuchs
- Ingmar Persson
2018 Pełny tekst PHYSICAL CHEMISTRY CHEMICAL PHYSICS
The structures of the N,N-dimethylformamide (dmf), N,N-dimethylacetamide (dma), and N,N-dimethylpropionamide (dmp) solvated strontium and barium ions have been determined in solution using large angle X-ray scattering and EXAFS spectroscopy. The strontium ion has a mean coordination number (CN) between 6.2 and 6.8, and the barium ion has a mean CN between 7.1 and 7.8 in these amide solvents. The non-integer numbers indicates that equilibria between different coordination numbers and geometries exist in these systems. Structural information of the alkali, alkaline earth, and selected transition metal and lanthanoid(III) ions, and the halide ions in water, methanol, ethanol, dimethylsulfoxide, formamide, dmf and dma has been combined with previously reported standard partial molar volumes, V0. The ionic radii and charge densities (charge/ionic volume), and corresponding V0 values have been used to gain information on the relationship between structural and volumetric properties. For the structure-breaking ions, i.e. the alkali metal and halide ions, there is an almost linear relationship between the ionic radius and V0. On the other hand, for the structure-making ions, here the alkaline earth, transition metal and lanthanoid(III) ions, a linear relationship is observed between the charge density and V0. Solvents with a well-defined bulk structure through hydrogen bonding, specifically, water, methanol and ethanol, will be more contracted through solvation than aprotic solvents, as the space between the solvent molecules is lost as a result of the hydrogen bonding. In this respect, methanol stands out as the most compressed solvent participating in solvation compared to its bulk structure.
On-line Search in Two-Dimensional Environment
- Dariusz Dereniowski
- Dorota Urbańska
2018
We consider the following on-line pursuit-evasion problem. A team of mobile agents called searchers starts at an arbitrary node of an unknown network. Their goal is to execute a search strategy that guarantees capturing a fast and invisible intruder regardless of its movements using as few searchers as possible. As a way of modeling two-dimensional shapes, we restrict our attention to networks that are embedded into partial grids: nodes are placed on the plane at integer coordinates and only nodes at distance one can be adjacent. We give an on-line algorithm for the searchers that allows them to compute a connected and monotone strategy that guarantees searching any unknown partial grid with the use of O(√n) searchers, where n is the number of nodes in the grid. We prove also a lower bound of Ω(√/n logn) in terms of achievable competitive ratio of any on-line algorithm.
Opakowania – źródłem zanieczyszczenia żywności. Problemy analityczne
- Natalia Jatkowska
- Jacek Namieśnik
2018 Analityka: Nauka i Praktyka
Jeszcze do niedawna materiały przeznaczone do kontaktu z żywnością (Food Contact Materials - FCM) nie były brane pod uwagę w kontekście stanowienia potencjalnego źródeł zanieczyszczeń żywności. Poświęcano im zdecydowanie mniej uwagi, niż np. pestycydom, czy metalom ciężkim. Jednak rozwój procedur analitycznych zapewniających możliwość oznaczenia analitów na coraz to niższych poziomach zawartości a także większa wiedza na temat procesów jakie zachodzą na skutek kontaktu materiału opakowaniowego z przechowywanym medium umożliwiły zidentyfikowanie tego kolejnego źródła zagrożeń. Obecnie w wielu ośrodkach naukowych trwają intensywne prace nad identyfikacją i ilościowym oznaczeniem wszystkich uwalnianych związków, produktów ich transformacji a także nad określeniem ryzyka zdrowotnego wynikającego z ekspozycji na działanie tych związków. W pracy omówione zostały najważniejsze informacje dotyczące zagadnień związanych z problemem migracji małocząsteczkowych składników z powierzchni materiału opakowaniowego. Szczególną uwagę poświęcono przeglądowi podejść zarówno instrumentalnych jak i bioanalitycznych stosowanych w badaniach opakowań.
Opinia biegłego ad hoc dla Sądu Okręgowego w Gdańsku, Wydział Gospodarczy
- Zygmunt Kurałowicz
2018
Dotyczy awarii konstrukcji hydrotechnicznej.
Opinia dotycząca jakości wykonania elementów balustrad przystanków PKM oraz możliwych przyczyn występowania korozji
- Krzysztof Krzysztofowicz
2018
Sporządzono opinię dotycząca występowania korozji elementów konstrukcyjnych balustrad na przystankach kolei PKM. Wskazano możliwe przyczyny korozji.
Opinia dotycząca zaworów firmy ARCO oraz "Duro" i "Calido" firmy Arka z/s w Siaowie
- Grzegorz Gajowiec
- Krzysztof Krzysztofowicz
- Jerzy Stuczyński
2018
Wykonano analizy składu chemicznego materiałów badanych zaworów celem stwierdzenia występowania pierwiastków niezgodnych z wymaganiami normy.
Opinia geotechniczna dotycząca odkrywki rury wodociągowej i wizji terenowej w sprawie przyczyn osunięcia skarpy w Gdyni - Kamienna Góra przy ulicy Sienkiewicza
- Lech Bałachowski
- Mariusz Wyroślak
- Kamila Międlarz
2018
Analiza przyczyn utraty stateczności skarpy
Opinia o innowacyjności w odniesieniu do planowanego efektu prac badawczo – rozwojowych nad nowymi rodzajami profili ciężkich wraz z akcesoriami komplementarnymi
- Ewa Wojciechowska
2018
Opinia o innowacyjności w odniesieniu do planowanego efektu prac badawczo – rozwojowych nad nowymi rodzajami profili ciężkich wraz z akcesoriami komplementarnymi. Opinia związana z wystąpieniem o środki na dofinansowanie innowacyjnej technologii produkcji. Mocowania, pomosty, belki, konstrukcje skręcane.
Opinia techniczna dot. wiaduktu WD-113 wykonywanego w km 2+842,39 drogi S6 w ramach realizacji przedsięwzięcia „Budowa obwodnicy Koszalina i Sianowa na S-6 wraz z odcinkiem S-11 od węzła „Koszalin” do węzła „Bielice”
- Mikołaj Miśkiewicz
- Jacek Chróścielewski
- Krzysztof Wilde
- Dawid Bruski
- Paweł Tysiąc
2018
Celem opracowania jest inwentaryzacja uszkodzeń konstrukcji wiaduktu WD-113P wykonywanego w km 2+842,76 drogi S-6 w ramach realizacji przedsięwzięcia „Budowa obwodnicy Koszalina i Sianowa na S-6 wraz z odcinkiem S-11 od węzła „Koszalin” do węzła „Bielice” oraz ocena ich wpływu na nośność obiektu, jak również zaopiniowanie zaproponowanych działań naprawczych. Zakres opracowania obejmuje: • zapoznanie się z dokumentacją [1], • wykonanie wizji lokalnej na budowie obiektu, • inwentaryzację uszkodzeń wraz z oceną ich wpływu na zachowanie konstrukcji, • podsumowanie i wnioski.