2019 - Publications Repository - Gdańsk University of Technology

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Publications from the year 2019

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Odzysk bioplastiku i celulozy z osadów ściekowych
- Dominika Grubba
- Jacek Mąkinia
2019 Full text Wodociągi - Kanalizacja
W ramach programu Energy and Raw Materials Factory prowadzone są badania nad odzyskiem celulozy oraz biotworzyw. Produkcja biopolimerów oraz bioplastiku ujawnia bowiem niezwykły potencjał obecny w kulturach mikrobiologicznych. Zaczęto także badać odzysk celulozy ze ścieków jako nowe źródła do produkcji kwasu mlekowego, z którego powstają bioplastiki.
Offshore surface waters of Antarctica are free of microplastics, as revealed by a circum-Antarctic study
- Piotr Kuklinski
- Leszek Wicikowski
- Mariusz Koper
- Tomasz Gralak,
- Hanna Leniec-Koper
- Michał Barasiński
- Magdalena Talar
- Ireneusz Kamiński
- Robert Kibart
- Wojciech Małecki
2019 Full text MARINE POLLUTION BULLETIN
In 2018, during a circum navigation of Antarctica below 62° S by the sailing boat Katharsis II, the presence of plastics was investigated with surface sampling nets at ten evenly spaced locations (every 36° of longitude). Although fibres that appeared to be plastic (particles up to 2 cm) were found in numbers ranging from 1 particle (0.002 particles per m3) to 171 particles (1.366 particles per m3) per station, a Fourier-transform infrared spectroscopy (FT-IR) analysis indicated that these particles were not composed of plastic. The fibres which superficially reminded plastic were composed of silica and are of biological origin most likely generated by phytoplankton (diatoms). Therefore, the offshore Antarctic locations were proven to be free of floating microplastics.
Ograniczanie zakażeń szpitalnych z wykorzystaniem środków architektonicznych
- Rafał Janowicz
2019 Full text
Statystyki zakażeń szpitalnych w Polsce skłaniają do wniosku, że należy poszukiwać optymalnych form minimalizacji ryzyka przenoszenia zakażeń, w tym drobnoustrojami lekoopornymi. Wśród elementów istotnych dla systemu kontroli zakażeń związanych z opieką zdrowotną w Polsce wymienia się m.in.: audyty, kontrole wewnętrzne, edukację personelu oraz działania mające wpływ na jego zachowanie, planowanie pracy zespołu, ocenę efektów działania. Niemniej obecne koncepcje higieny nie doceniają w wystarczający sposób roli jednego z aspektów procesu prewencji zakażeń – architektury samego obiektu szpitalnego. Prawidłowa organizacja architektoniczna jednostki medycznej, procesu projektowego, a następnie realizacyjnego jest sposobem na zminimalizowanie możliwości wystąpienia zagrożenia epidemicznego. Odpowiednio zaplanowany i zrealizowany jej układ funkcjonalno-przestrzenny, wspomagany przez zaawansowane układy instalacji technicznych, jak wentylacja mechaniczna, systemy teletechniczne oraz skuteczna dekontaminacja, jest w stanie zapewnić prawidłowe funkcjonowanie i bezpieczne dla użytkowników warunki sanitarne i higieniczne.
Określenie parametrów modelowania geometrii krzyżownic rozjazdów zwyczajnych dla potrzeb budowy i utrzymania linii kolejowych
- Piotr Omieczyński
2019 Zeszyty Naukowo-Techniczne Stowarzyszenia Inżynierów i Techników Komunikacji w Krakowie. Seria: Materiały Konferencyjne
Zdecydowana większość rozjazdów występująca na liniach kolejowych w Polsce to rozjazdy zwyczajne o typowym zestawie parametrów. Z tego powodu analiza przypadków nietypowych (takich jak rozjazdy o zmiennej krzywiźnie toru zwrotnego) może być utrudniona. Wirtualny model geometryczno-konstrukcyjny rozjazdu, generowany w oparciu o metody analityczne, stanowić może narzędzie użyteczne w sferze projektowania, konstrukcji oraz diagnostyki rozjazdu wbudowanego w tor. W artykule zaprezentowano główne założenia dotyczące modelowania rozjazdów, ustalono zakres niezbędnych danych wejściowych. Przedstawiono przykłady parametryzacji elementu krzyżownicy w kontekście geometrycznym oraz konstrukcyjnym (projektowanie krzyżownicy zwyczajnej rozjazdu oraz problem doboru wariantu przytwierdzenia w rejonie montażu krzyżownicy). W podsumowaniu przedstawiono możliwości i kierunki dalszej rozbudowy modelu.
On Adaptive Spectrum Estimation of Multivariate Autoregressive Locally Stationary Processes
- Michał Meller
- Maciej Niedźwiecki
- Damian Chojnacki
2019
Autoregressive modeling is a widespread parametricspectrum estimation method. It is well known that, in the caseof stationary processes with unknown order, its accuracy canbe improved by averaging models of different complexity usingsuitably chosen weights. The paper proposes an extension of thistechnique to the case of multivariate locally stationary processes.The proposed solution is based on local autoregressive modeling,and combines model averaging with estimation bandwidth adap-tation. Results of simulations demonstrate that the application ofthe proposed decision rules allows one to outperform the standardapproach, which does not include the bandwidth adaptation.
On Anti-Plane Surface Waves Considering Highly Anisotropic Surface Elasticity Constitutive Relations
- Victor Eremeev
2019
Within the framework of highly anisotropic surface elasticity model we discuss the propagation of new type of surface waves that are anti-plane surface waves. By the highly anisotropic surface elasticity model we mean the model with a surface strain energy density which depends on incomplete set of second derivatives of displacements. From the physical point of view this model corresponds to a coating made of a family of parallel long fibers which posses bending and extensional stiffness in one direction only. As for other models with surface energy there exist anti-plane surface waves. In the paper the dispersion relation is derived and dependence on the material parameters is analyzed.
On Dynamic Boundary Conditions Within the Linear Steigmann-Ogden Model of Surface Elasticity and Strain Gradient Elasticity
- Victor Eremeev
2019
Within the strain gradient elasticity we discuss the dynamic boundary conditions taking into account surface stresses described by the Steigmann–Ogden model. The variational approach is applied with the use of the least action functional. The functional is represented as a sum of surface and volume integrals. The surface strain and kinetic energy densities are introduced. The Toupin–Mindlin formulation of the strain gradient elasticity is considered. As a result, we derived the motion equations and the natural boundary conditions which include inertia terms.
On energy, exergy, and environmental aspects of a combined gas-steam cycle for heat and power generation undergoing a process of retrofitting by steam injection
- Paweł Ziółkowski
- Tomasz Kowalczyk
- Marcin Daniel Lemański
- Janusz Badur
2019 ENERGY CONVERSION AND MANAGEMENT
The paper presents a study of retrofitting of a combined heat and power (CHP) plant aimed to increase the electric to heating power ratio. The modification would involve diverting part of the steam to the gas turbine, instead of letting it go to the steam turbine, using injection technique into a combustion chamber. Therefore, two potential retrofitting approaches are analyzed: steam injection gas turbine (STIGT) and combined steam injection gas turbine (CSTIGT). STIGT is a classic solution where live steam is diverted before the valves of a steam turbine. In CSTIGT steam is received from the turbine extraction. Both solutions increase electric power output of the cycle (STIGT by 1.33 MWe, CSTIGT by 2.68 MWe), decrease heating power (STIGT by 52.90 MWth, CSTIGT by 31.75 MWth) and decrease CHP energy efficiency (STIGT by 32 pp., CSTIGT by 22 pp.). The exergy analyses indicate that the highest exergy losses occur in the combustion chamber (61.30 MW for the reference cycle). Steam injection increase this value by 7.34 MW in STIGT and 5.65 MW in CSTIGT. However, decreasing of combustion temperature prevent the NOx emission by more than 8 g/MWh for both solutions.
ON ESTIMATION OF OCCUPANT SAFETY IN VEHICULAR CRASHES INTO ROADSIDE OBSTACLES USING NON-LINEAR DYNAMIC ANALYSIS
- Krzysztof Wilde
- Arkadiusz Tilsen
- Stanisław Burzyński
- Wojciech Witkowski
2019
The article describes a comparison of two general methods of occupants safety estimation based on a numerical examples. The so-called direct method is mainly based on the Head Injury Criterion of a crash test dummy in a vehicle with passive safety system while the indirect method uses a European standards approach to estimate impact severity level. Numerical simulations in LS-DYNA have been conducted.
On existence and uniqueness of weak solutions for linear pantographic beam lattices models
- Victor Eremeev
- Faris Saeed Alzahrani
- Antonio Cazzani
- Francesco Dell’isola
- Tasawar Hayat
- Emilio Turco
- Violetta Konopińska-Zmysłowska
2019 Full text CONTINUUM MECHANICS AND THERMODYNAMICS
In this paper, we discuss well-posedness of the boundary-value problems arising in some “gradientincomplete” strain-gradient elasticity models, which appear in the study of homogenized models for a large class ofmetamaterials whosemicrostructures can be regarded as beam lattices constrained with internal pivots. We use the attribute “gradient-incomplete” strain-gradient elasticity for a model in which the considered strain energy density depends on displacements and only on some specific partial derivatives among those constituting displacements first and second gradients. So, unlike to the models of strain-gradient elasticity considered up-to-now, the strain energy density which we consider here is in a sense degenerated, since it does not contain the full set of second derivatives of the displacement field. Such mathematical problem was motivated by a recently introduced new class of metamaterials (whose microstructure is constituted by the so-called pantographic beam lattices) and by woven fabrics. Indeed, as from the physical point of view such materials are strongly anisotropic, it is not surprising that themathematical models to be introduced must reflect such property also by considering an expression for deformation energy involving only some among the higher partial derivatives of displacement fields. As a consequence, the differential operators considered here, in the framework of introduced models, are neither elliptic nor strong elliptic as, in general, they belong to the class so-called hypoelliptic operators. Following (Eremeyev et al. in J Elast 132:175–196, 2018. https://doi.org/10.1007/s10659-017-9660-3) we present well-posedness results in the case of the boundary-value problems for small (linearized) spatial deformations of pantographic sheets, i.e., 2D continua, when deforming in 3D space. In order to prove the existence and uniqueness of weak solutions, we introduce a class of subsets of anisotropic Sobolev’s space defined as the energy space E relative to specifically assigned boundary conditions. As introduced by Sergey M. Nikolskii, an anisotropic Sobolev space consists of functions having different differential properties in different coordinate directions.
On Kinetic Nature of Hysteresis Phenomena in Stress-Induced Phase Transformations
- Holm Altenbach
- Alexander Belyaev
- Victor Eremeev
- Anton Krivtsov
- Alexey Porubov
2019
A simplest model is developed which demonstrates that hysteresis phenomena in stress-induced phase transformations may have a kinetic nature and follow from the discrepancy between strain rate and characteristic rate of the new phase growth.
On Noncausal Identification of Nonstationary Multivariate Autoregressive Processes
- Maciej Niedźwiecki
- Marcin Ciołek
2019 Full text IEEE TRANSACTIONS ON SIGNAL PROCESSING
The problem of identification of nonstationary multivariate autoregressive processes using noncausal local estimation schemes is considered and a new approach to joint selection of the model order and the estimation bandwidth is proposed. The new selection rule, based on evaluation of pseudoprediction errors, is compared with the previously proposed one, based on the modified Akaike’s final prediction error criterion.
On Non-holonomic Boundary Conditions within the Nonlinear Cosserat Continuum
- Victor Eremeev
2019
Within the framework of the nonlinear micropolar elastic continuum we discuss non-holonomic kinematic boundary conditions. By non-holonomic boundary conditions we mean linear relations between virtual displacements and virtual rotations given on the boundary. Such boundary conditions can be used for modelling of complex material interactions in the vicinity of the boundaries and interfaces.
On Nonlinear Dynamic Theory of Thin Plates with Surface Stresses
- Holm Altenbach
- Victor Eremeev
2019
We discuss the modelling of dynamics of thin plates considering surface stresses according to Gurtin–Murdoch surface elasticity. Taking into account the surface mass density we derive the two-dimensional (2D) equations of motion. For the reduction of the three-dimensional (3D) motion equations to the 2D ones we use the trough-the-thickness integration procedure. As a result, the 2D dynamic parameters of the plate depend not only on the density distribution in the bulk but also on the surface mass density.
On some problems in determining tensile parameters of concrete model from size effect tests
- Ireneusz Marzec
- Jerzy Bobiński
2019 Full text Polish Maritime Research
The paper presents results of numerical simulations of size effect phenomenon in concrete specimens. The behaviour of in-plane geometrically similar notched and unnotched beams under three-point bending is investigated. In total 18 beams are analysed. Concrete beams of four different sizes and five different notch to depth ratios are simulated. Two methods are applied to describe cracks. First, an elasto-plastic constitutive law with a Rankine criterion and an associated flow rule is defined. In order to obtain mesh independent results, an integral non-local theory is used as a regularisation method in the softening regime. Alternatively, cracks are described in a discrete way within Extended Finite Element Method (XFEM). Two softening relationships in the softening regime are studied: a bilinear and an exponential curve. Obtained numerical results are compared with experimental outcomes recently reported in literature. Calculated maximum forces (nominal strengths) are quantitatively verified against experimental values, but the force – displacement curves are also examined. It is shown that both approaches give results consistent with experiments. Moreover, both softening curves with different initial fracture energies can produce similar force-displacement curves.
On the Agile Mindset of an Effective Team – An Industrial Opinion Survey
- Jakub Miler
- Paulina Gaida
2019 Full text Annals of Computer Science and Information Systems
In this paper we present the results of an opinion survey among 52 agile practitioners who evaluated the importance of 26 selected elements of the agile mindset to the effectiveness of an agile team. In total, we have identified 70 unique agile mindset elements based on 11 literature sources and 5 interviews with industry experts. 7 elements belonged to the “support for business goals” category, 20 to the “relationships within the team” category, 24 to the “individual features” category, and 19 to the “organization of work” category. Our survey shows the relative importance of the selected 26 agile mindset elements according to our respondents which is not fully consistent with the principles behind the Agile Manifesto.
On the Buckling Response of Axially Pressurized Nanotubes Based on a Novel Nonlocal Beam Theory
- Mohammad Malikan
2019 Full text Journal of Applied and Computational Mechanics
In the present study, the buckling analysis of single-walled carbon nanotubes (SWCNT) on the basis of a new refined beam theory is analyzed. The SWCNT is modeled as an elastic beam subjected to unidirectional compressive loads. To achieve this aim, the new proposed beam theory has only one unknown variable which leads to one equation similar to Euler beam theory and is also free from any shear correction factors. The equilibrium equation is formulated by the nonlocal elasticity theory in order to predict small-scale effects. The equation is solved by Navier’s approach by which critical buckling loads are obtained for simple boundary conditions. Finally, to approve the results of the new beam theory, some available well-known references are compared.
On the correspondence between two- and three-dimensional Eshelby tensors
- Victor Eremeev
- Violetta Konopińska-Zmysłowska
2019 Full text CONTINUUM MECHANICS AND THERMODYNAMICS
We consider both three-dimensional (3D) and two-dimensional (2D) Eshelby tensors known also as energy–momentum tensors or chemical potential tensors, which are introduced within the nonlinear elasticity and the resultant nonlinear shell theory, respectively. We demonstrate that 2D Eshelby tensor is introduced earlier directly using 2D constitutive equations of nonlinear shells and can be derived also using the throughthe-thickness procedure applied to a 3D shell-like body.
On the Equations of the Surface Elasticity Model Based on the Theory of Polymeric Brushes
- Roman Gerasimov
- Tatiana Petrova
- Victor Eremeev
- Andrei Maximov
- Olga Maximova
2019
Motivating by theory of polymers, in particular, by the models of polymeric brushes we present here the homogenized (continual) two-dimensional (2D) model of surface elasticity. A polymeric brush consists of an system of almost aligned rigid polymeric chains. The interaction between chain links are described through Stockmayer potential, which take into account also dipole-dipole interactions. The presented 2D model can be treated as an highly anisotropic 2D strain gradient elasticity. The surface strain energy contains both first and second derivatives of the surface field of displacements. So it represents an intermediate class of 2D models of the surface elasticity such as Gurtin-Murdoch and Steigmann-Ogden ones.
On the production of electricity in Poland using a geothermal binary power plant - A thermodynamic overview - Part I
- Janusz Badur
- Rafał Hyrzyński
- Marcin Daniel Lemański
- Paweł Ziółkowski
- Sebastian Bykuć
2019
Poland has a significant potential of geothermal energy. However, the high-temperature sources that are needed to drive power plants are found in relatively few places. Therefore, the objective of this paper is to consider any location in the northern part of Poland as a possible place to build a binary power plant. A scientific research was confirmed the existence of an elevated temperature gradient in this region. The hot rocks have an approximate temperature of 120 oC at depths of 3000 m. It was assumed that a hot brine emanates from these sources at a volume flow rate of 400m3/h and drives the Organic Rankine Cycle with isobutane as a working medium. The First Law thermal efficiency and the power output were estimated at 10.5% and 1.79 MWe, respectively. In addition, the Second Law thermal efficiency were calculated at 29.0%. All results were compared with the other binary power plants and they confirm that establishing the binary power plant in Poland would be thermodynamically justified.