2021 - Repozytorium publikacji - Politechnika Gdańska

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On nonlinear dilatational strain gradient elasticity
- Victor Eremeev
- Antonio Cazzani
- Francesco dell'Isola
2021 Pełny tekst CONTINUUM MECHANICS AND THERMODYNAMICS
We call nonlinear dilatational strain gradient elasticity the theory in which the specific class of dilatational second gradient continua is considered: those whose deformation energy depends, in an objective way, on the gradient of placement and on the gradient of the determinant of the gradient of placement. It is an interesting particular case of complete Toupin–Mindlin nonlinear strain gradient elasticity: indeed, in it, the only second gradient effects are due to the inhomogeneous dilatation state of the considered deformable body. The dilatational second gradient continua are strictly related to other generalized models with scalar (one-dimensional) microstructure as those considered in poroelasticity. They could be also regarded to be the result of a kind of “solidification” of the strain gradient fluids known as Korteweg or Cahn–Hilliard fluids. Using the variational approach we derive, for dilatational second gradient continua the Euler–Lagrange equilibrium conditions in both Lagrangian and Eulerian descriptions. In particular, we show that the considered continua can support contact forces concentrated on edges but also on surface curves in the faces of piecewise orientable contact surfaces. The conditions characterizing the possible externally applicable double forces and curve forces are found and examined in detail. As a result of linearization the case of small deformations is also presented. The peculiarities of the model is illustrated through axial deformations of a thick-walled elastic tube and the propagation of dilatational waves.
On possible applications of media described by fractional-order models in electromagnetic cloaking
- Tomasz Stefański
2021 Communications in Nonlinear Science and Numerical Simulation
The purpose of this paper is to open a scientific discussion on possible applications of media described by fractional-order (FO) models (FOMs) in electromagnetic cloaking. A 2-D cloak based on active sources and the surface equivalence theorem is simulated. It employs a medium described by FOM in communication with sources cancelling the scattered field. A perfect electromagnetic active cloak is thereby demonstrated with the use of a finite-difference time-domain method combined with a simulation algorithm of non-monochromatic wave propagation in the media described by FOM. The application of constitutive relations based on FOMs in Maxwell’s equations provides solutions which correspond to the results reported for the time-fractional diffusion-wave equation, which is non-relativistic, like the classical diffusion equation. This property is employed in the presented cloaking scheme for communication with active current sources around the cloak, which cancel the scattered field of an object inside the cloak. Although in the real world perfect invisibility is impossible to obtain due to the constraint of light speed, it is possible to obtain a perfect cloak in theoretical considerations by using FO formulation of electromagnetism. It is worth noticing that numerous literature sources experimentally confirm the existence of electromagnetic media described by FOMs; hence, the presented numerical results should hopefully stimulate further investigations related to applications of FOMs in electromagnetic cloaking.
On the Application of Magnetoacoustic Emission for a Nondestructive Assessment of the Post Welding Heat Treatment of High Chromium Steel Weld Seams
- Leszek Piotrowski
- Marek Chmielewski
- Grzegorz Golański
- K. Wojsyk
2021 Pełny tekst JOURNAL OF NONDESTRUCTIVE EVALUATION
The paper analyses the possibility of post weld heat treatment (PWHT) quality assessment with the help of magnetoacoustic emission (MAE) signal measurements. Two welded superheater tubes, made of high chromium VM12 steel, were analysed—as welded and heat treated one. The analysed sample in the as welded state exhibited significantly higher hardness, accompanied by a big difference in the MAE signal intensity (of order of about 50%). In order to explain that, the influence of tempering on the MAE signal intensity is demonstrated for the very similar X20CrMoV12.1 steel. It is shown that the observed increase of the MAE intensity as a function of annealing time is directly correlated with the change in hardness. The as described dependence allows to propose a method based on the MAE signal measurements as a new tool for the PWHT assessment.
On the Characteristic Graph of a Discrete Symmetric Channel
- Dariusz Dereniowski
- Marcin Jurkiewicz
2021 IEEE TRANSACTIONS ON INFORMATION THEORY
We present some characterizations of characteristic graphs of row and/or column symmetric channels. We also give a polynomial-time algorithm that decides whether there exists a discrete symmetric channel whose characteristic graph is equal to a given input graph. In addition, we show several applications of our results.
On the current state of dovetail wall-corner joints in wooden Greek Catholic churches in Polish Subcarpathia with structural and sensitivity analyses
- Izabela Lubowiecka
- Tomasz Zybała
- Grzegorz Bukal
- Marcin Krajewski
- Marcin Kujawa
- Paweł Kłosowski
2021 Pełny tekst International Journal of Architectural Heritage
This paper describes the current condition of some dovetail joints which form the wall corners of two Greek Catholic churches of wooden construction in Polish Subcarpathia. It also gives the historical background of the sacral architecture of that region. The two structures, which represent the same type of log corner joints are situated in Chotylub and Cewków. The buildings were examined e.g. for damage, wood moisture content, out-of-plane deviations and changes in the geometry of the walls. The study is based on in-situ examination and structural analysis of the joints. Finite element simulations of the statics of joints built of old, and mixture of old and new, wood are performed in order to show how the change of material properties affects their structural behaviour. Also a sensitivity analysis is performed to describe the effect on potential repairs that combining old damp wood with new and dry joint members might have.
On the generalized model of shell structures with functional cross-sections
- Shahriar Dastjerdi
- Mohammad Malikan
- Victor Eremeev
- Bekir Akgöz
- Ömer Civalek
2021 Pełny tekst COMPOSITE STRUCTURES
In the present study, a single general formulation has been presented for the analysis of various shell-shaped structures. The proposed model is comprehensive and a variety of theories can be used based on it. The cross-section of the shell structure can be arbitrarily analyzed with the presented equations. In other words, various types of shell structures, including cylindrical, conical, spherical, elliptical, hyperbolic, parabolic, and any non-geometric structure with functional cross-section, can be modeled mechanically with only one partial differential equation system. The obtained equations have been solved by applying SAPM semi-analytical solution method. In order to present a comprehensive research, dynamic nonlinear analysis is considered. The variation of material properties through the thickness has been assumed as functionally graded and its effect on the strength of the shell structure with the functional cross-section has been investigated. The numerical results have been compared with available papers and also with FEM results for some structures that there is no paper available for validation. Different types of shell structures have been studied in terms of cross-sectional shape and properties. Finally, the effects of some important factors on the results such as boundary conditions, nonlinear analysis, dynamic analysis, and rotation of the structure around its central axis have been conducted thoroughly. This study and its original governing equations can be considered as a comprehensive reference for mechanical analysis of various shell structures with functional cross-sectional shape.
On the influence of a surface roughness on propagation of anti-plane short-length localized waves in a medium with surface coating
- Gennadi Mikhasev
- Marina Botogova
- Victor Eremeev
2021 Pełny tekst INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
We discuss the propagation of localized surface waves in the framework of the linear Gurtin–Murdoch surface elasticity and taking into account a roughness of a free boundary. We derive a boundary-value problem for anti-plane motions with curvilinear boundary and surface stresses. Using the asymptotic technique developed earlier, we obtain the form of a localized wave and analyze its amplitude evolution. As the main result we present the dependence of the wave amplitude on the roughness magnitude. The presented results could be used for non-destructive evaluation of the surface microstructure using surface waves-based devices. In particular, measuring the decay rate with the depth one can estimate roughness of a surface and appearance of new surface defects.
On the mechanism of photocatalytic reactions on CuxO@TiO2 core–shell photocatalysts
- Kunlei Wang
- Zuzanna Bielan
- Maya Endo-Kimura
- Marcin Janczarek
- Dong Zhang
- Damian Kowalski
- Anna Zielińska-Jurek
- Agata Markowska-Szczupak
- Bunsho Ohtani
- Ewa Kowalska
2021 Journal of Materials Chemistry A
Titania (titanium(IV) oxide) is a highly active, stable, cheap and abundant photocatalyst, and is thus commonly applied in various environmental applications. However, two main shortcomings of titania, i.e., charge carrier recombination and inactivity under visible-light (vis) irradiation, should be overcome for widespread commercialization. Accordingly, titania has been doped, surface modified and coupled with various ions/compounds, including narrower bandgap semiconductors, such as oxides of copper and silver. Unfortunately, these oxides are not as stable as titania, and thus loss of activity under long-term irradiation (photo-corrosion) has been observed. Therefore, this study has focused on the preparation of stable coupled photocatalysts, i.e., CuxO@TiO2 core–shell nanostructures, by the microemulsion method from commercial Cu2O as a core and TiO2 (ST01-fine anatase) as a shell. The photocatalysts have been characterized by DRS, SEM, TEM, XRD, XPS and reversed double-beam photo-acoustic spectroscopy (RDB-PAS) methods, and activity tests under UV (anaerobic dehydrogenation of methanol and oxidative decomposition of acetic acid) and vis (phenol oxidation) irradiation. The higher activities of coupled photocatalysts than their counterparts have been found in all studied systems under UV/vis irradiation. Moreover, long-term experiments (10 h) have shown high stability of CuxO@TiO2. However, the change of oxidation state of copper has also been observed, i.e., to negative and positive values, confirming the charge transfer according to the Z-scheme under UV irradiation and type-II heterojunction under vis irradiation, respectively. The property-governed activity and the mechanism have been discussed in detail.
On the problem of optimised allocation of water quality sensors and actuators in DWDS
- Tomasz Zubowicz
- Rafał Łangowski
2021 Pełny tekst
The problems of water quality sensors and actuators placement in drinking water distribution systems (DWDSs) are addressed as separate, primarily. However, against the background of control systems theory, the nature of DWDSs dynamics indicates that these both problems are interdependent and impact the design of related water quality monitoring and control structures and algorithms. The research work presented in this paper is to investigate the state-of-the-art in this field and discuss the problems of water quality sensors and actuators placement within DWDS and to highlight the potential benefits of considering the joint task of their allocation.
On thermal stability of piezo-flexomagnetic microbeams considering different temperature distributions
- Mohammad Malikan
- Tomasz Wiczenbach
- Victor Eremeev
2021 Pełny tekst CONTINUUM MECHANICS AND THERMODYNAMICS
By relying on the Euler–Bernoulli beam model and energy variational formula, we indicate critical temperature causes in the buckling of piezo-flexomagnetic microscale beams. The corresponding size-dependent approach is underlying as a second strain gradient theory. Small deformations of elastic solids are assessed, and the mathematical discussion is linear. Regardless of the pyromagnetic effects, the thermal loading of the thermal environment varies in three states along with the thickness, which is linear, uniform, and parabolic forms. We then establish the results by developing consistent shape functions that independently evaluate boundary conditions. Next, we analytically develop and explore the effective properties of the studied beam concerning vital factors. It was achieved that piezomagnetic-flexomagnetic microbeams are more affected by the thermal environment while the thermal loading is parabolically distributed across the thickness, particularly when the boundaries involve simple supports.
On thio‐substituted N‐heterocyclic arsines
- Johannes Bender
- Agnieszka Skowrońska
- Anna Dołęga
- Martin Nieger
- Dietrich Gudat
2021 Pełny tekst ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
Metathesis of N-heterocyclic chloroarsines with sulfur-based nucleophiles furnished thio-substituted 1,3,2-diazarsolidines and 1,3,2-diazarsolenes. Crystallographic and NMR spectroscopic studies revealed that a thiocyanato-diazarsolene exhibits a salt-like structure composed of weakly interacting thiocyanate and arsenium ions, while the remaining products formed neutral molecules. The structural data indicate that the heterocyclic framework induces an elongation of exocyclic As−S bonds that is more prominent in diazarsolenes than in diazarsolidines and parallels the bond polarisation effect established for N-heterocyclic phosphines. The NMR data suggest that diazarsolenes undergo facile inversion of the pyramidal configuration at arsenic, which was successfully modelled by DFT studies.
On topology optimization of large deformation contact-aided shape morphing compliant mechanisms
- Prabhat Kumar
- Roger Sauer
- Anupam Saxena
2021 Pełny tekst MECHANISM AND MACHINE THEORY
A topology optimization approach for designing large deformation contact-aided shape morphing compliant mechanisms is presented. Such mechanisms can be used in varying operating conditions. Design domains are described by regular hexagonal elements. Negative circular masks are employed to perform dual task, i.e., to decide material states of each element and also, to generate rigid contact surfaces. Each mask is characterized by five design variables, which are mutated by a zero-order based hill-climbing optimizer. Geometric and material nonlinearities are considered. Continuity in normals to boundaries of the candidate designs is ensured using a boundary resolution and smoothing scheme. Nonlinear mechanical equilibrium equations are solved using the Newton–Raphson method. An updated Lagrange approach in association with segment-to-segment contact method is employed for the contact formulation. Both mutual and self contact modes are permitted. Efficacy of the approach is demonstrated by designing four contact-aided shape morphing compliant mechanisms for different desired curves. Performance of the deformed profiles is verified using a commercial software. The effect of frictional contact surface on the actual profile is also studied.
On weak solutions of boundary value problems within the surface elasticity of Nth order
- Victor Eremeev
- Leonid Lebedev
- Michael Cloud
2021 ZAMM-Zeitschrift fur Angewandte Mathematik und Mechanik
A study of existence and uniqueness of weak solutions to boundary value problems describing an elastic body with weakly nonlocal surface elasticity is presented. The chosen model incorporates the surface strain energy as a quadratic function of the surface strain tensor and the surface deformation gradients up to Nth order. The virtual work principle, extended for higher‐order strain gradient media, serves as a basis for defining the weak solution. In order to characterize the smoothness of such solutions, certain energy functional spaces of Sobolev type are introduced. Compared with the solutions obtained in classical linear elasticity, weak solutions for solids with surface stresses are smoother on the boundary; more precisely, a weak solution belongs to 1()∩() where ⊂≡ and ⊂ℝ3 .
On Wrinkling in Sandwich Panels with an Orthotropic Core
- Zbigniew Pozorski
- Jolanta Pozorska
- Ireneusz Kreja
- Łukasz Smakosz
2021 Pełny tekst Materials
This paper deals with the local loss of stability (wrinkling) problem of a thin facing of a sandwich panel. Classical solutions to the problem of facing instability resting on a homogeneous and isotropic substructure (a core) are compared. The relations between strain energy components associated with different forms of core deformations are discussed. Next, a new solution for the orthotropic core is presented in detail, which is consistent with the classic solution for the isotropic core. Selected numerical examples confirm the correctness of the analytical formulas. In the last part, parametric analyses are carried out to illustrate the sensitivity of wrinkling stress to a change in the material parameters of the core. These analyses illustrate the possibility of using the equations derived in the article for the variability of Poisson’s ratio from -1 to 1 and for material parameters strongly deviating from isotropy.
Onboard Energy Storage and Power Management Systems forAll-Electric Cargo Vessel Concept
- Dariusz Karkosiński
- Wojciech Aleksander Rosiński
- Piotr Deinrych
- Szymon Potrykus
2021 Pełny tekst ENERGIES
This paper presents an innovative approach to the design of a forthcoming, fully electric-powered cargo vessel. This work begins by defining problems that need to be solved when designingvessels of this kind. Using available literature and market research, a solution for the design of apower management system and a battery management system for a cargo vessel of up to 1504 TEUcapacity was developed. The proposed solution contains an innovative approach with three parallelenergy sources. The solution takes into consideration the possible necessity for zero-emission workwith the optional function of operation as an autonomous vessel. Energy storage system based onlithium-ion battery banks with a possibility of expanding the capacity is also described in this work asit is the core part of the proposed solution. It is estimated that the operation range for zero-emissionwork mode of up to 136 nautical miles can be achieved through the application of all fore-mentioned parts.
Ongoing progress on novel nanocomposite membranes for the separation of heavy metals from contaminated water
- Roberto Castro Munoz
- Luisa Loreti González-Melgoza
- Octavio García-Depraect
2021 Pełny tekst CHEMOSPHERE
Membranes, as the primary separation element of membrane-based processes, have greatly attracted the attention of researchers in several water treatment applications, including wastewater treatment, water purification, water disinfection, toxic and non-toxic chemical molecules, heavy metals, among others. Today, the removal of heavy metals from water has become challenging, in which chemical engineers are approaching new materials in membrane technologies. Therefore, the current review elucidates the progress of using different concepts of membranes and potential novel materials for such separations, identifying that polymeric membranes can exhibit a removal efficiency from 77 up to 99%; while novel nanocomposite membranes are able to offer complete removal of heavy metals (up to 100%), together with unprecedented permeation rates (from 80 up to 1, 300 L m−2 h−1). Thereby, the review also addresses the highlighted literature survey of using polymeric and nanocomposite membranes for heavy metal removal, highlighting the relevant insights and denoted metal uptake mechanisms. Moreover, it gives up-to-date information related to those novel nanocomposite materials and their contribution to heavy metals separation. Finally, the concluding remarks, future perspectives, and strategies for new researchers in the field are given according to the recent findings of this comprehensive review.
On-line assessment of oil quality during deep frying using an electronic nose and proton transfer reaction mass spectrometry
- Tomasz Majchrzak
- Wojciech Wojnowski
- Agnieszka Głowacz-Różyńska
- Andrzej Wasik
2021 FOOD CONTROL
We describe a novel method for the quality assessment of oil utilized for deep frying. The method is based on the analysis of frying fumes using a custom electronic nose. The quality score could be obtained after less than 3 min of analysis and without interrupting the frying process or sampling the oil directly. The obtained results were correlated with the peroxide value using a multivariate linear regression model. The most relevant variables were selected based on heat maps and on the analysis of variance. The coefficients of determination for palm oil and rapeseed oil were 0.920 and 0.935, respectively. Real-time monitoring of selected VOCs in the frying fumes was performed using proton transfer reaction mass spectrometry. It was shown that 1-heptanol is a possible indicator of rapeseed oil’s quality. The proposed method might be used to supplement the currently available techniques and could find implementation in the non-invasive on-line assessment of frying oils’ quality during deep frying of foodstuffs
Ontological Model for Contextual Data Defining Time Series for Emotion Recognition and Analysis
- Teresa Zawadzka
- Wojciech Waloszek
- Aleksandra Karpus
- Sara Zapalowska
- Michał Wróbel
2021 Pełny tekst IEEE Access
One of the major challenges facing the field of Affective Computing is the reusability of datasets. Existing affective-related datasets are not consistent with each other, they store a variety of information in different forms, different formats, and the terms used to describe them are not unified. This paper proposes a new ontology, ROAD, as a solution to this problem, by formally describing the datasets and unifying the terms used. The developed ontology allows information about the origin and meaning of the data to be modeled, i.e., time series, representing both emotional states and features derived from biosignals. Furthermore, the ROAD ontology is extensible and not application-oriented, thus it can be used to store data from a wide range of Affective Computing experiments. The ontology was validated by modeling data obtained from one experiment on the AMIGOS dataset. The approach proposed in the paper can be used both by researchers who create new datasets or want to reuse existing ones, and for those who want to process data from experiments in a more automated way.
Open Innovation Competence for a Future-Proof Workforce: A Comparative Study from Four European Universities
- Marita Mcphillips
- Magdalena Licznerska
2021 Pełny tekst Journal of Theoretical and Applied Electronic Commerce Research
Digital transformation is a key driving force of open innovation to capture and transfer knowledge inside and outside of a company’s bounds. New challenges in organizing multiple knowledge flows imply the need for increased competences related to this paradigm of future employees. In this article, we organize and aggregate the competencies required for open innovation collaboration and develop a competence profile that organizes individual competencies in an open innovation context. Based on elements of the European Entrepreneurship Competence Framework, we delineate an OI Competence Profile and list the core competencies to manage and accelerate the inflow and outflow of knowledge. We explore this profile by comparing data from 2332 students from four European universities to find differences in the distribution of OI competencies between countries. The study contributes to understanding the individual competencies that target the future OI needs of companies necessary in the context of digital transformation. It also introduces an interdisciplinary approach to integrate the research streams of management practice, open innovation, and entrepreneurial education.
Opinia na temat celowości oraz zakresu rzeczowego remontu tokarki karuzelowej FKD-60/80. Ekspertyza techniczna opracowana na zlecenie ENEROMONTAŻ-PÓŁNOC GDYNIA S.A.
- Wojciech Blacharski
2021
Opracowana Opinia Jednostki Naukowej dotyczyła ciężkiej tokarki karuzelowej typu FKD-60/80 ze sterowaniem CNC. Na podstawie przeprowadzonego w miejscu użytkowania tej obrabiarki audytu, dokonano oceny obecnego stanu maszyny oraz przeanalizowano przyczyny awarii, które zdarzały się w okresie jej eksploatacji. Zakres analizy przyczyn stanów awaryjnych obejmował: - awarie zespołu elektrowrzeciona oraz układów hydraulicznych zawartych w tym zespole; - obserwowane ugięcia i błędy geometryczne stołu obrotowego (oś C) ulokowanego na prowadnicy hydrostatycznej oraz ocenę dopuszczalnej obciążalności tego stołu; - problemy z napędem ruchu belki w kierunku pionowym (oś W); - usterki w układach smarowania i układach hydraulicznych; - problemy z układem sterowania. W opracowaniu określono zakres koniecznych prac remontowych oraz zaproponowano wprowadzenie działań zapobiegawczych w ramach utrzymania ruchu. Przeanalizowano również ograniczenia możliwości obróbkowych tokarki FKD-60/80 w kontekście potrzeb produkcyjnych firmy użytkującej tą maszynę. Opracowanie zawiera 28 stron, 7 rysunków i 7 fotografii.