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On the correspondence between two- and three-dimensional Eshelby tensors
PublikacjaWe 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...
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Robust four-node elements based on Hu–Washizu principle for nonlinear analysis of Cosserat shells
PublikacjaMixed 4-node shell elements with the drilling rotation and Cosserat-type strain measures based onthe three-field Hu–Washizu principle are proposed. In the formulation, apart from displacement and rotationfields, both strain and stress resultant fields are treated as independent. The elements are derived in the frame-work of a general nonlinear 6-parameter shell theory dedicated to the analysis of multifold irregular shells.The...
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Bending analysis of functionally graded nanoplates based on a higher-order shear deformation theory using dynamic relaxation method
PublikacjaIn this paper, bending analysis of rectangular functionally graded (FG) nanoplates under a uniform transverse load has been considered based on the modified couple stress theory. Using Hamilton’s principle, governing equations are derived based on a higher-order shear deformation theory (HSDT). The set of coupled equations are solved using the dynamic relaxation (DR) method combined with finite difference (FD) discretization technique...
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On thermal stability of piezo-flexomagnetic microbeams considering different temperature distributions
PublikacjaBy 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...
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Computational analysis of an infinite magneto-thermoelastic solid periodically dispersed with varying heat flow based on non-local Moore–Gibson–Thompson approach
PublikacjaIn this investigation, a computational analysis is conducted to study a magneto-thermoelastic problem for an isotropic perfectly conducting half-space medium. The medium is subjected to a periodic heat flow in the presence of a continuous longitude magnetic field. Based on Moore–Gibson–Thompson equation, a new generalized model has been investigated to address the considered problem. The introduced model can be formulated by combining...
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On nonlinear dilatational strain gradient elasticity
PublikacjaWe 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...
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Flexomagneticity in buckled shear deformable hard-magnetic soft structures
PublikacjaThis research work performs the first time exploring and addressing the flexomagnetic property in a shear deformable piezomagnetic structure. The strain gradient reveals flexomagneticity in a magnetization phenomenon of structures regardless of their atomic lattice is symmetrical or asymmetrical. It is assumed that a synchronous converse magnetization couples both piezomagnetic and flexomagnetic features into the material structure....
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Thermal buckling of functionally graded piezomagnetic micro- and nanobeams presenting the flexomagnetic effect
PublikacjaGalerkin weighted residual method (GWRM) is applied and implemented to address the axial stability and bifurcation point of a functionally graded piezomagnetic structure containing flexomagneticity in a thermal environment. The continuum specimen involves an exponential mass distributed in a heterogeneous media with a constant square cross section. The physical neutral plane is investigated to postulate functionally graded material...
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Selected local stability problems of channel section flanges made of aluminium alloys
PublikacjaThe paper addresses the issue of local buckling of compressed flanges of cold-formed thin-walled channel columns and beams with nonstandard flanges composed of aluminium alloys. The material behaviour follows the Ramberg–Osgood law. It should be noted that the proposed solution may be also applied for other materials, for example: stainless steel, carbon steel. The paper is motivated by an increasing interest in nonstandard cold-formed...
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On FEM analysis of Cosserat-type stiffened shells. Static and stability linear analysis
PublikacjaThe present research investigates the theory and numerical analysis of shells stiffened with beams in the framework based on the geometrically exact theories of shells and beams. Shell’s and beam’s kinematics are described by the Cosserat surface and the Cosserat rod respectively, which are consistent including deformation and strain measures. A FEM approximation of the virtual work principle leads to the conforming shell and beam...
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Fluid–solid interaction on a thin platelet with high-velocity flow: vibration modelling and experiment
PublikacjaThe paper concerns the nonlinear behaviour of a thin platelet that is streamlined in an aerodynamic tunnel. The air velocity in the aerodynamic tunnel was at 858.9 km/h or 0.7 Ma (Ma—Mach number is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound). This experiment was numerically simulated using FSI (fluid–solid interaction) tools, namely the coupling...
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Thermomagnetic behavior of a semiconductor material heated by pulsed excitation based on the fourth-order MGT photothermal model
PublikacjaThis article proposes a photothermal model to reveal the thermo-magneto-mechanical properties of semiconductor materials, including coupled diffusion equations for thermal conductivity, elasticity, and excess carrier density. The proposed model is developed to account for the optical heating that occurs through the semiconductor medium. The Moore–Gibson–Thompson (MGT) equation of the fourth-order serves as the theoretical framework...
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On the exact equilibrium conditions of irregular shells reinforced by beams along the junctions
PublikacjaThe exact, resultant equilibrium conditions for irregular shells reinforced by beams along the junctions are formulated. The equilibrium conditions are derived by performing direct integration of the global equilibrium conditions of continuum mechanics. New, exact resultant static continuity conditions along the singular curve modelling reinforced junction are presented. The results do not depend on shell thickness, internal through-the-thickness...
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Cavity-expansion approximation for projectile impact and penetration into sand
PublikacjaA one-dimensional problem of a spherical cavity expanding at a constant velocity from zero initial radius in an infinite granular medium, which has the first-kind self-similar solution, is considered. We are solving this dynamic spherical cavity-expansion problem to model rigid spheres penetrating into a granular media. Elastic–plastic deformation of the granular media is described in a barotropic approximation, using the high-pressure...
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A model of damaged media used for describing the process of non-stationary creep and long-term strength of polycrystalline structural alloys
PublikacjaThe main laws of the processes of creep and long-term strength of polycrystalline structural alloys are considered. From the viewpoint of continuum damaged media (CDM), a mathematical model is developed that describes the processes of viscoplastic deformation and damage accumulation under creep. The problem of determining material parameters and scalar functions of the developed constitutive relations based on the results of specially...
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Nonlinear free and forced vibrations of a dielectric elastomer-based microcantilever for atomic force microscopy
PublikacjaThe majority of atomic force microcode (AFM) probes work based on piezoelectric actuation. However, some undesirable phenomena such as creep and hysteresis may appear in the piezoelectric actuators that limit their applications. This paper proposes a novel AFM probe based on dielectric elastomer actuators (DEAs). The DE is modeled via the use of a hyperelastic Cosserat model. Size effects and geometric nonlinearity are included...
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Experimental study and numerical simulation of the dynamic penetration into dry clay
PublikacjaTests of dry clay were carried out in a uniaxial stress state using the experimental setup which implements the split Hopkinson pressure bar method. Based on the results of these experiments, the compressive strength of clay was determined as an important element of S.S. Grigoryan’s model of the soil medium. In addition, the parameters of this model are determined from the results of experiments using the modified Kolsky method...
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Piotr Samól dr inż. arch.
OsobyPiotr Samól jest adiunktem w Katedrze Historii, Teorii Architektury i Konserwacji Zabytków Wydziału Architektury Politechniki Gdańskiej. Ukończył architekturę i historię. Jego badania skupiają się na zagadnieniach historii architektury oraz urbanistyki Gdańska i regionu nadbałtyckiego. Rozprawę doktorską (nauki techniczne, architektura i urbanistyka) o architekturze kościołów dominikańskich w dawnym państwie zakonu krzyżackiego...
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Credibility of Threats to Jam Anonymous Traffic Remapping Attacks in Ad Hoc WLANs
PublikacjaIn ad hoc networks, selfish stations can pursue a better quality of service (QoS) by performing traffic remapping attacks (TRAs), i.e., by falsely assigning their traffic to a higher priority class, which can hurt honest stations’ QoS. To discourage the attackers, honest stations can announce their dissatisfaction with the perceived QoS. If such a threat fails, a costly data frame jamming defense can be launched. We analyze the...
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On dynamics of origami-inspired rod
PublikacjaWe discuss the dynamics of a relatively simple origami-inspired structure considering discrete and continuum models. The latter was derived as a certain limit of the discrete model. Here we analyze small in-plane deformations and related equations of infinitesimal motions. For both models, dispersion relations were derived and compared. The comparison of the dispersion relations showed that the continuum model can capture the behavior...
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Synthesis and antimicrobial activity of 6-sulfo-6-deoxy-D-glucosamine and its derivatives
Publikacja6-Sulfo-6-deoxy-D-glucosamine (GlcN6S), 6-sulfo-6-deoxy-D-glucosaminitol (ADGS) and their N-acetyl and methyl ester derivatives have been synthesized and tested as inhibitors of enzymes catalyzing reactions of the UDP-GlcNAc pathway in bacteria and yeasts. GlcN6S and ADGS at micromolar concentrations inhibited glucosamine-6-phosphate (GlcN6P) synthase of microbial origin. The former was also inhibitory towards fungal GlcN6P N-acetyl...
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Muhammad Shahzeb Shahzeb Khan Phd Chemistry (Continued)
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Design thinking qualifications framework – standardizing the innovative approach to entrepreneurial education delivery to engineering students
PublikacjaHighly competitive labor market stimulates increasing expectations towards fresh university alumni. It is not enough to be an expert - well educated and often experienced - in chosen discipline. High variability of the business environment, continuous change, number of risks, together with higher work demand than supply, shape clear employers’ expectations: entrepreneurial employees are wanted. On this ground a need for entrepreneurial...
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Development of factors and measurement of personnel risk in the marketing services of four Polish pharmaceutical companies
Dane BadawczeThis text contains the presentation and analysis of research results in relation to four companies (A, B, C, D), according to the adopted case study method.Further considerations should be preceded by the assumption that personal risk factors often affect the level of this risk in various directions, so their final impact is the result of the shaping...
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Krzysztof Leja dr hab. inż.
OsobyKrzysztof Leja, absolwent Wydziału Fizyki Technicznej i Matematyki Stosowanej Politechniki Gdańskiej, doktor habilitowany nauk o zarządzaniu. Obecnie prodziekan ds. nauki Wydziału Zarządzania i Ekonomii Politechniki Gdańskiej. Zainteresowania badawcze koncentrują się wokół problematyki doskonalenia organizacji i zarządzania współczesną uczelnią. Kierował i uczestniczył w projektach krajowych i międzynarodowych dotyczących badań...
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Karol Niklas dr hab. inż.
OsobyKarol NIKLAS jest profesorem Politechniki Gdańskiej (Wydział Inżynierii Mechanicznej i Okrętownictwa, Instytut Budowy Okrętów). Pracę dyplomową magisterską na kierunku "Budowy okrętów morskich" w specjalności "Budowa małych statków i jachtów" obronił w 2007 roku. W 2008 roku ukończył studia podyplomowe w specjalności "Nowoczesne Metody Symulacyjne w Technice" na Wydziale Fizyki i Matematyki Stosowanej. W 2014 roku obronił rozprawę...
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Modelling method for a class of distributed-lumped parameter systems
PublikacjaThe paper presents an alternative approach for modelling and order reduction of continuous system. The proposed methodology combines application of two methods: the modal decomposition method and the rigid finite element method. The given continuous structure is divided into 1D continuous substructures. For each 1D substructure modal decomposition and reduction procedure is applied. Interactions between substructures are described...
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Towards β-selectivity in functional estrogen receptor antagonists
PublikacjaBased on the benzo[b]naphtho[1,2-d]furan and benzo[b]naphtho[1,2-d]thiophene frameworks, a series of ligands with different basic side chains (BSCs) has been synthesized and pharmacologically evaluated. Also, their binding modes have been modelled using docking techniques. It was found that the introduction of a BSC in these systems brings about a decrease of affinity for both estrogen receptors α and β in an in vitro competitive...
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Performance of isotropic constitutive laws in simulating failure mechanisms in scaled RC beams
PublikacjaResults of numerical calculations of reinforced concrete (RC) beams are presented. Based on experimental results on longitudinally reinforced specimens of different sizes and shapes are investigated. Four different continuum constitutive laws with isotropic softening are used: one defined within continuum damage mechanics, an elasto-plastic with the Rankine criterion in tension and the Drucker-Prager criterion in compression, a...
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On Effective Bending Stiffness of a Laminate Nanoplate Considering Steigmann–Ogden Surface Elasticity
PublikacjaAs at the nanoscale the surface-to-volume ratio may be comparable with any characteristic length, while the material properties may essentially depend on surface/interface energy properties. In order to get effective material properties at the nanoscale, one can use various generalized models of continuum. In particular, within the framework of continuum mechanics, the surface elasticity is applied to the modelling of surface-related...
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Experimental investigations and simulations of the microturbine unit with permanent magnet generator
PublikacjaIn dispersed power generation, low power devices are used for local combined generating of heat end electric power. There are developing concepts of micropower plants with electric generators driven by steam or gas microturbines. The paper presents the results of an experimental investigations of the microturbine set consists of the turbine with partial admission, permanent magnet generator and three phase AC-to-DC rectifier. The...
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PLANNING AND ANALYSIS OF EARTHQUAKE DISASTER RELIEF WORK IN ETHIOPIA
PublikacjaThis paper addresses dynamic planning and analysis of earthquake disaster relief work by analysis the disaster throughout the technical and procedural method. And combine this analysis as continues assessment for better input to investigating planning disaster for discontinuous economic growth. This implemented, considering the vulnerability and hazard analysis as a procedural analysis disaster to estimating acceptance risk leveling...
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Ireneusz Kreja dr hab. inż.
OsobyAbsolwent klasy matematycznej I Liceum Ogólnokształcącego w Gdańsku im. Mikołaja Kopernika (1974). Absolwent Wydziału Budownictwa Lądowego Politechniki Gdańskiej (1979). Od 1979 pracuje na PG. W 1989 uzyskał doktorat (z wyróżnieniem), na Wydziale Budownictwa Lądowego, a w 2008 habilitował się (również z wyróżnieniem) na Wydziale Inżynierii Lądowej i Środowiska PG. Od 2011 jest profesorem PG. Na Politechnice Gdańskiej pełnił funkcje:...
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Design, synthesis, and biological evaluation of tetrahydroquinolinones and tetrahydroquinolines with anticancer activity
PublikacjaColorectal cancer (CRC) is the most commonly diagnosed cancer in Europe and the United States and the second leading cause of cancer related mortality. A therapeutic strategy used for the treatment of CRC involves targeting the intracellular levels of reactive oxygen species (ROS). In this study, we synthesized a series of novel tetrahydroquinolinones and assessed their ability to inhibit CRC growth and proliferation by evoking...
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Two examples of Quantum Dynamical Semigroups
PublikacjaThe Hamiltonians of the considered bi-partite systems are of the form $$ H_{S,R} = H_S /times 1_R + Q_{S} /times M_R + 1_S /times H_R $$ Subindex $S$ corresponds to the observed system and $R$ to the reservoir (the enviroment of $S$). Two classes of systems are distinguished: the discrete-continuous...
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Daria Filipiak-Kowszyk dr inż.
OsobyDaria Filipiak-Kowszyk ukończyła IV Liceum Ogólnokształcące im. Tadeusza Kościuszki w Toruniu w 2008 roku. Naukę kontynuowała na kierunku Geodezja i Kartografia na Wydziale Geodezji i Gospodarki Przestrzennej w Olsztynie (studia I i II stopnia) uzyskując tytuł magistra inżyniera w 2013 roku. W 2013 roku, po studiach podjęła pracę w Katedrze Geodezji na Wydziale Inżynierii Lądowej i Środowiska Politechniki Gdańskiej na stanowisku...
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Wavelet filtering of signals without using model functions
PublikacjaThe effective wavelet filtering of real signals is impossible without determining their shape. The shape of a real signal is related to its wavelet spectrum. For shape analysis, a continuous color wavelet spectrogram of signal level is often used. The disadvantage of continuous wavelet spectrogram is the complexity of analyzing a blurry color image. A real signal with additive noise strongly distorts the spectrogram based on continuous...
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Novel chalcone-derived pyrazoles as potential therapeutic agents for the treatment of non-small cell lung cancer
PublikacjaLung cancer is considered to account for approximately one-fifth of all malignant tumor-related deaths worldwide and is therefore one of the most lethal malignancies. Pyrazole scaffold possesses a wide range of biological and pharmacological activities, which play important roles in medicinal chemistry. The present study reports the synthesis and in vitro biological characterization of nine pyrazoles derived from chalcones as potential...
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Distribution Transformer with Multi-Zone Voltage Regulation for Smart Grid System Application
PublikacjaThe article presents four concepts of the multi-zone voltage regulation (MZVR) system. It is a combination of a distribution transformer with an on-load tap-changer, for step voltage regulation, and a power electronic converter, dimensioned for a fraction of MZVR power, realizing continuous voltage regulation, supplemented by a special switch, the so-called bypass. This allows voltage regulation at high resolution, wide range and...
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ANALYZING TITLES OF ECONOMY NEWS TO UNDERSTAND IMPACT OF COVID-19 ON ECONOMICAL SITUATION
PublikacjaCovid-19 affected the whole world in a short time, causing serious panic and uncertainty in society. Because it was an unprecedented disease, the medical community has worked hard to find out how to deal with it, and it continues to do so. The rapid spread of the disease, the shortage of hospital capacity and the increase in deaths drove the whole world to a closure, so to speak. In this time period, life in the world came to a...
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Karol Moszyk
OsobyCertified Lean Six Sigma Black Belt with maritime transport and operations academic background. Logistics professional with a broad experience in various container terminal positions, reporting to Chief Operating Officer. Professional ambition is to combine an open and pragmatic leadership style with a customer focus supported by structured data to realize business improvements and create added value for company and customers.Work...
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Bifurcation of equilibrium forms of an elastic rod on a two-parameter Winkler foundation
PublikacjaWe consider two-parameter bifurcation of equilibrium states of an elastic rod on a deformable foundation. Our main theorem shows that bifurcation occurs if and only if the linearization of our problem has nontrivial solutions. In fact our proof, based on the concept of the Brouwer degree, gives more, namely that from each bifurcation point there branches off a continuum of solutions.
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The influence of feed rate and shear forces on the devulcanization process of ground tire rubber (GTR) conducted in a co-rotating twin screw extruder
PublikacjaThe search for new ways to recycling of rubber waste has been the aim of many studies conducted by research centers and companiesworldwide. The results of our investigations on the process of continuous thermomechanical devulcanization of ground tire rubber using a twin screw extruder are presented.We used a co-rotating twin screw extruder with a special configuration of plasticizing unit, enabling generation of considerable shear...
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Lefschetz periodic point free self-maps of compact manifolds
PublikacjaLet f be a self-map of a compact connected manifold M. We characterize Lefschetz periodic point free continuous self-maps of M for several classes of manifolds and generalize the results of Guirao and Llibre [J.L.G. Guirao, J. Llibre, On the Lefschetz periodic point free continuous self-maps on connected compact manifolds,
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Janusz Datta prof. dr hab. inż.
OsobyJanusz Datta w roku 1988 ukończył studia na Wydziale Chemicznym Politechniki Gdańskiej. Po ich zakończeniu został zatrudniony na Wydziale Chemicznym w Zakładzie, a potem po reorganizacji, w Katedrze Technologii Polimerów, gdzie przez sześć lat pracował na stanowisku naukowo-technicznym. W tym okresie zdobywał doświadczenie uczestnicząc w licznych wyjazdach do Zakładów Chemicznych „Zachem” Bydgoszcz, gdzie brał udział w pracach...
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The generalization by simplification operator with Sester’s method of objects representing groups of buildings in Gdańsk district - scale 1:10000. Data from OSM
Dane BadawczeThe process of automatic generalization is one of the elements of spatial data preparation for the purpose of creating digital cartographic studies. The presented data include a part of the process of generalization of building groups obtained from the Open Street Map databases (OSM) [1].
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Modeling of Composite Shells in 6-Parameter Nonlinear Theory with Drilling Degree of Freedom
PublikacjaWithin the framework of a 6-parameter nonlinear shell theory, with strain measures of Cosserat type, constitutive relations are proposed for thin elastic composite shells. The material law is expressed in terms of five engineering constants of classical anisotropic continuum plus an additional parameter accounting for drilling stiffness. The theory allows for unlimited displacements and rotations. A number of examples are presented...
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SOILPROM Modelowanie transportu zanieczyszczeń w kontinuum grunt-woda-atmosfera, oraz wpływ na funkcje ekosystemu
ProjektyProjekt realizowany w Katedra Geotechniki i Inżynierii Wodnej zgodnie z porozumieniem 101156589 - SOILPROM - HORIZON-MISS-2023-SOIL-01 z dnia 2024-05-17
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A model development and experimental verification for a vapour microturbine with a permanent magnet synchronous generator
PublikacjaVapour microturbines with permanent magnet synchronous generators are implemented in micropower plants for dispersed power generation systems. The dynamic model of such a microturbine set was developed and presented. The developed relations result from the generic equations. Experimental data for two different working medium were used for model verification. A microturbine set model was tested during the changes in the parameters...
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Lefschetz periodic point free self-maps of compact manifolds
PublikacjaLet f be a self-map of a compact connected manifold M. We characterize Lefschetz periodic point free continuous self-maps of M for several classes of manifolds and generalize the results of Guirao and Llibre [J.L.G. Guirao, J. Llibre, On the Lefschetz periodic point free continuous self-maps on connected compact manifolds, Topology Appl. 158 (16) (2011) 2165-2169].