Search results for: LEGENDRE POLYNOMIALS EXPANSION
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Place Attachment and Collective Action Tendency
PublicationThree studies were carried out to examine how place attachment and collective action tendency are related and what role self-expansion and social interactions play in this relationship. In the first study (N = 156) we found that a more active form of attachment – place discovered – is a significant predictor of tendency to engage in collective action in favor of one’s neighborhood. In the second study (N = 197), we focused on...
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Structural properties of mixed conductor Ba1−xGd1−yLax+yCo2O6−δ
PublicationBa1−xGd1−yLax+yCo2O6−δ (BGLC) compositions with large compositional ranges of Ba, Gd, and La have been characterised with respect to phase compositions, structure, and thermal and chemical expansion. The results show a system with large compositional flexibility, enabling tuning of functional properties and thermal and chemical expansion. We show anisotropic chemical expansion and detailed refinements of emerging phases as La is...
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Implementation of Hermite-Ritz method and Navier’s Technique for Vibration of Functionally Graded Porous Nanobeam Embedded in Winkler-Pasternak Elastic Foundation Using bi-Helmholtz type of nonlocal elasticity
PublicationPresent study is devoted to investigating the vibration characteristics of Functionally Graded (FG) porous nanobeam embedded in an elastic substrate of Winkler-Pasternak type. Classical beam theory (CBT) or Euler-Bernoulli beam theory (EBT) has been incorporated to address the displacement of the FG nanobeam. Bi-Helmholtz type of nonlocal elasticity is being used to capture the small scale effect of the FG nanobeam. Further, the...
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A spline-based FE approach to modelling of high frequency dynamics of 1-D structures
PublicationIn this paper a computational methodology leading to the development of a new class of FEs, based on the application of continuous and smooth approximation polynomials, being splines, has been presented. Application of the splines as appropriately defined piecewise elemental shape functions led the authors to the formulation of a new approach for FEM, named as spFEM, where contrary to the well-known NURBS approach, the boundaries...
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Non-linear circuit model of a single doubly-fed induction machine formulated in natural axes for drive systems simulation purposes
PublicationMathematical modelling and a circuit model formulated in natural axes of a single doubly-fed induction machine, with the account of magnetic circuit nonlinearity are presented in the paper. Derivation of the model differential equations was based on Lagrange's energy method. State functions of magnetic elements in the model are non-linear and depend on all currents flowing in the machine windings and on the angle of rotor position....
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Dilatometry results of SrTi0.50Fe0.50O3-d powder
Open Research DataThis dataset contains results of dilatometry measurements of SrTi0.50Fe0.50O3-d powder. The investigation of the linear thermal expansion was carried out using a Netzsch DIL402 dilatometer. The SrTi0.50Fe0.50O3-d powder was formed into cylinders and heat up to 1100 °C with a heating rate of 5 °C min−1, dwelled for 15 min, and then cooled at a rate of...
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Dilatometry results of SrTi0.65Fe0.35O3-d powder
Open Research DataThis dataset contains results of dilatometry measurements of SrTi0.65Fe0.35O3-d powder. The investigation of the linear thermal expansion was carried out using a Netzsch DIL402 dilatometer. The SrTi0.65Fe0.35O3-d powder was formed into cylinders and heat up to 1100 °C with a heating rate of 5 °C min−1, dwelled for 15 min, and then cooled at a rate of...
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Dilatometry results of SrTi0.30Fe0.70O3-d powder
Open Research DataThis dataset contains results of dilatometry measurements of SrTi0.30Fe0.70O3-d powder. The investigation of the linear thermal expansion was carried out using a Netzsch DIL402 dilatometer. The SrTi0.30Fe0.70O3-d powder was formed into cylinders and heat up to 1100 °C with a heating rate of 5 °C min−1, dwelled for 15 min, and then cooled at a rate of...
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An Enhanced Reduced Basis Method for Wideband Finite Element Method Simulations
PublicationIn this paper, we present a novel strategy for selecting expansion points in the reduced basis method. A single computation of the error estimator is used to select a few expansion points in the multi-parameter space simultaneously. The number of selected points is determined adaptively, based on the accuracy of the current reduced model. The reliability and efficiency of this proposed approach are illustrated by numerical tests...
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Numerical Test for Stability Evaluation of Discrete-Time Systems
PublicationIn this paper, a new numerical test for stability evaluation of discrete-time systems is presented. It is based on modern root-finding techniques at the complex plane employing the Delaunay triangulation and Cauchy's Argument Principle. The method evaluates if a system is stable and returns possible values and multiplicities of unstable zeros of the characteristic equation. For state-space discrete-time models, the developed test...
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High-temperature properties of titanium-substituted yttrium niobate
Publicationhe defect fluorite titanium-doped yttrium niobate samples Y3Nb1−xTixO7−δ have been synthesized and investigated by the means of high-temperature X-ray diffraction, dilatometry, and thermogravimetry. Thermal expansion coefficients (TECs) as well as chemical expansion coefficients for material with 5, 10, and 15 mol% of titanium were determined. All investigated samples exhibit chemical contraction caused by Ti doping. The values...
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Badania charakterystyki obciążeń oddziałujących na modułowe urządzenie dylatacyjne w pasie ruchu ciężkiego autostrady A8
PublicationPrzedstawiono badania urządzenia dylatacyjnego typu nożycowego. Dokonano statycznych i dynamicznych pomiarów odkształceń oraz przemieszczeń konstrukcji nożyc na najbardziej obciążonym pasie autostrady A8. Określono wpływ oddziaływania dynamicznego oraz sporządzono histogramy obciążeń i współczynników przewyższenia dynamicznego na podstawie pomiarów ciągłych w okresie nasilonego ruchu. Wskazano przyczyny degradacji urządzenia. Odniesiono...
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Karolina Lademann Mgr
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KRYTERIA STOSOWANE W WIELOKRYTERIALNYM PLANOWANIU ROZWOJU SYSTEMU ELEKTROENERGETYCZNEGO
PublicationProblematyka planowania rozwoju systemów elektroenergetycznych jest zagadnieniem często podejmowanym w badaniach optymalizacyjnych ze względu na wagę i zasięg problemu. Rozwój techniki komputerowej pozwolił na połączenie tematyki optymalizacji struktury wytwarzania i planowania sieci elektroenergetycznej, co jest zagadnieniem wielowątkowym oraz wielowymiarowym. W prezentowanym artykule przedstawiono kryteria stosowane w analizach...
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Modyfikacja połączenia dźwigara ze słupem w konstrukcji stalowej Terminalu T2 Portu Lotniczego w Gdańsku
PublicationW2015 r. ukończono rozbudowę Terminalu T2 Portu Lotniczego im. Lecha Wałęsy wGdańsku. Politechnika Gdańska pełniła nadzór naukowy nad rozbudową obiektu. Wykonano wiele analiz, których celem była weryfikacja pracy konstrukcji w fazach montażu oraz w stanie docelowym. Wnioski z przeprowadzonych badań doprowadziły do modyfikacji oparcia dźwigarów dachowych na stalowych słupach nośnych, z uwagi na stwierdzone lokalne przekroczenia...
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Microstructure and Electrical Properties of Fe,Cu Substituted (Co,Mn)3O4 Thin Films
PublicationIn this work, thin films (~1000 nm) of a pure MnCo2O4 spinel together with its partially substituted derivatives (MnCo1.6Cu0.2Fe0.2O4, MnCo1.6Cu0.4O4, MnCo1.6Fe0.4O4) were prepared by spray pyrolysis and were evaluated for electrical conductivity. Doping by Cu increases the electrical conductivity, whereas doping by Fe decreases the conductivity. For Cu containing samples, rapid grain growth occurs and these samples develop cracks...
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The point estimate method in a reticulated shell reliability analysis
PublicationThe objective of this paper is to present an application of the point estimate method (PEM) that can determine the probabilistic moments for engineering structures. The method is reasonably robust and adequately accurate for a wide range of practical problems. It is a special case of numerical quadrature based on orthogonal polynomials. The main advantage of this method is that, unlike FORM or SORM, it is not necessary to carry...
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Solving Boundary Value Problems for Second Order Singularly Perturbed Delay Differential Equations by ε-Approximate Fixed-Point Method
PublicationIn this paper, the boundary value problem for second order singularly perturbed delay differential equation is reduced to a fixed-point problem v = Av with a properly chosen (generally nonlinear) operator A. The unknown fixed-point v is approximated by cubic spline vh defined by its values vi = vh(ti) at grid points ti, i = 0, 1, ... ,N. The necessary for construction the cubic spline and missing the first derivatives at the boundary...
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Dispersive Delay Structures With Asymmetric Arbitrary Group-Delay Response Using Coupled-Resonator Networks With Frequency-Variant Couplings
PublicationThis article reports the design of coupled-resonatorbased microwave dispersive delay structures (DDSs) with arbitrary asymmetric-type group delay response. The design process exploits a coupling matrix representation of the DDS circuit as a network of resonators with frequency-variant couplings (FVCs). The group delay response is shaped using complex transmission zeros (TZs) created by dispersive cross-couplings. We also present an...
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Polynomial analysis as a new way of describing dynamic impedance spectra – Differential and relative impedance spectra
PublicationModel measurements of an equivalent electrical system were carried out using the technique of Dynamic Electrochemical Impedance Spectroscopy. The measurement took the form of potentiodynamic changes imposed on the tested system. Using the possibility of continuous impedance measurements, an attempt was made to develop an original and innovative method of analyzing impedance spectrograms, which is termed polynomial analysis. As...
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Information Retrieval with the Use of Music Clustering by Directions Algorithm
PublicationThis paper introduces the Music Clustering by Directions (MCBD) algorithm. The algorithm is designed to support users of query by humming systems in formulating queries. This kind of systems makes it possible to retrieve songs and tunes on the basis of a melody recorded by the user. The Music Clustering by Directions algorithm is a kind of an interactive query expansion method. On the basis of query, the algorithm provides suggestions...
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LSA Is not Dead: Improving Results of Domain-Specific Information Retrieval System Using Stack Overflow Questions Tags
PublicationThe paper presents the approach to using tags from Stack Overflow questions as a data source in the process of building domain-specific unsupervised term embeddings. Using a huge dataset of Stack Overflow posts, our solution employs the LSA algorithm to learn latent representations of information technology terms. The paper also presents the Teamy.ai system, currently developed by Scalac company, which serves as a platform that...
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Assessment, optimisation and working fluid comparison of organic rankine cycle combined with negative CO2 gas power plant system
PublicationThis study aims to investigate the application of the Organic Rankine Cycle (ORC) as an alternative to low-pressure expansion in the negative CO2 power plant (nCO2PP). The reason for this study is that a detailed analysis of nCO2PP indicates a certain amount of waste heat present in the exhaust gas from the high-to-intermediate pressure gas turbine. Some of this energy can be used by the application of the expansion in a low-pressure...
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Evaluation of electrical parameters of traction supply system for complex railway traffic conditions, using simulation methods
PublicationDevelopment of electrified transport systems, railways modernization, expansion of urban transport networks, purchases of modern rolling stock causes that updating of electric traction supply system is necessary. This chapter presents an effective method for electrical parameters of traction supply system evaluation, using simulation methods.
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Firm-Level Internationalisation from the Theoretical Perspective: Knowledge-based Approach
PublicationThe objective of the paper is to present the role of knowledge in internationalisation process of the firm as well as the selected theoretical proposals which assume that the role of knowledge in international expansion of firms is crucial. The article first presents the selected but best known, the oldest internationalisation paradigms. Then it shows the direction of development of theoretical perspectives.
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Effect of isovalent substitution on microstructure and phase transition of LaNb1−xMxO4 (M=Sb, V or Ta; x=0.05–0.3)
PublicationLaNb1−xMxO4 oxides with pentavalent elements of different ionic sizes (M=Sb, Ta and V, x=0.05–0.3) were synthesized by the solid state reaction method. Special interest was devoted to the antimony substituted lanthanum niobate which is a new material in this group. Rietveld analysis of the X-ray diffraction patterns was used to determine the influence of the material composition on unit cell parameters. On the basis of dilatometric...
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Numerical Test for Stability Evaluation of Analog Circuits
PublicationIn this contribution, a new numerical test for the stability evaluation of analog circuits is presented. Usually, if an analog circuit is unstable then the roots of its characteristic equation are localized on the right half-plane of the Laplace s- plane. Because this region is unbounded, we employ the bilinear transformation to map it into the unit disc on the complex plane. Hence, the existence of any root inside the unit disc...
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A Review: Applications of the Spectral Finite Element Method
PublicationThe Spectral Finite Element Technique (SFEM) has Several Applications in the Sciences, Engineering, and Mathematics, which will be Covered in this Review Article. The Spectral Finite Element Method (SFEM) is a Variant of the Traditional Finite Element Method FEM that Makes use of Higher Order Basis Functions (FEM). One of the most Fundamental Numerical Techniques Employed in the Numerical Simulation is the SFEM, which Outperforms...
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Finite element models used in diagnostics of transverse cracks in bridge approach pavement
Open Research DataTransverse cracks in the asphalt pavement were observed on bridge structures next to single-module expansion joints with a 5 meter approach slab set at the depth of 1 m. The finite element (FE) models of the approach pavement were created to investigate the reasons of premature cracking and crack initiation mechanism over the back edge of the abutment...
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Generation of random fields to reflect material and geometric imperfections of plates and shells
PublicationThe paper covers two patterns of random field generation: conditional acceptance – rejection method and Karhunen – Loève expansion. The generation of two-dimensional random fields is essential in plates and shells analysis, allowing for a relevant limit and critical state assessment of geometrically and ma-terially imperfect structures. The features of both generation methods dedicate them to selected problems.
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Paweł Szymon Dąbrowski dr inż.
PeopleDr. Eng. Paweł Szymon Dąbrowski studied geodesy and cartography at the University of Warmia and Mazury in Olsztyn from 2004-2009, where he obtained the title of Master of Science in Engineering. In the years 2009-2016, he worked as a land surveyor in Iława and Gdańsk. He gained professional experience during the construction of the Pomeranian Metropolitan Railway, which helped him obtain a national surveying license in 2015. In...
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Resonant Frequencies in the Open Microstrip Structures Placed on Curved Surfaces
PublicationThe paper presents the research on open microstrip structures placed on curved surfaces such as cylindrical, elliptical or spherical. The numerical analysis of investigated structures is based on expansion of electric and magnetic fields into suitable function series. Utilizing the continuity conditions the boundary problem is formulated which is solved with the use of method of moments. The investigated structures find application...
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Some new soliton solutions to the higher dimensional Burger–Huxley and Shallow water waves equation with couple of integration architectonic
PublicationIn this paper, we retrieve some traveling wave, periodic solutions, bell shaped, rational, kink and anti-kink type and Jacobi elliptic functions of Burger’s equation and Shallow water wave equation with the aid of various integration schemes like improved -expansion scheme and Jacobi elliptic function method respectively. We also present our solutions graphically in various dimensions.
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Selective Harmonic Elimination PWM For a Cascaded Multi-level Inverter
PublicationThis paper deals with the selective harmonic elimination pulse width modulation (SHE-PWM) technique. This technique is used for the elimination of selected dominant low order harmonics in the multi-level inverter output voltage. The presence of these harmonics is the essential drawback of such kind of inverters; especially when it is used for the control of different AC drivers. The SHE-PWM is based...
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General solution of quantum mechanical equations of motion with time-dependent Hamiltonians: A Lie algebraic approach
PublicationThe unitary operators U(t), describing the quantum time evolution of systems with a time-dependent Hamiltonian, can be constructed in an explicit manner using the method of time-dependent invariants. We clarify the role of Lie-algebraic techniques in this context and elaborate the theory for SU(2) and SU(1,1). In these cases we give explicit formulae for obtaining general solutions from special ones. We show that the constructions...
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Empirical investigation on labour market interactions in an enlarged Europe
PublicationThis paper proposes an empirical assessment of economic interactions between the labour markets ofthe integrating EU over the period of time 1995-2005. Drawing on recently made available industrystatistics, we provide a sector level study (13 tradable sectors, including manufacturing and services),analysing the contemporary evolution of domestic and trade partners' employment levels. Given theintensification of trade relations...
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Impact of strontium non-stoichiometry of SrxTi0.3Fe0.7O3-δ on structural, electrical, and electrochemical properties for potential oxygen electrode of intermediate temperature solid oxide cells
PublicationThis work presents the results of a comprehensive study on the impact of the A-site non-stoichiometry of SrxTi0.3Fe0.7O3-δ (x = 0.90, 0.95, 1.00, 1.05) ceramics on their physicochemical properties. The materials were fabricated by the conventional solid-state reaction method and their structure was determined by X-ray diffractometry, X-ray photoelectron spectroscopy and electron microscopy. Their sintering and thermal expansion...
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Resonant Frequencies in Microstrip Structure with Omega Medium Substrate
PublicationThe paper presents the research on a rectangular microstrip structure with multilayer substrate containing dielectric and omega medium layers. The effect of pseudochiral medium layer location in the substrate and its thickness on the resonant frequency of the rectangular microstrip structure is investigated. The numerical analysis of investigated structures is based on expansion of electric and magnetic fields. Utilizing the continuity...
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Analytical calculations of scattering lengths for a class of long-range potentials of interest for atomic physics
PublicationWe derive two equivalent analytical expressions for an $l$th partial-wave scattering length $a_{l}$ for central potentials with long-range tails of the form % \begin{math} \displaystyle V(r)=-\frac{\hbar^{2}}{2m}\frac{Br^{n-4}}{(r^{n-2}+R^{n-2})^{2}} -\frac{\hbar^{2}}{2m}\frac{C}{r^{2}(r^{n-2}+R^{n-2})}, \end{math} % ($r\geqslant r_{s}$, $R>0$). % For $C=0$, this family of potentials reduces to the Lenz potentials discussed in...
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Correlation–polarization effects in electron/positron scattering from acetylene: A comparison of computational models
PublicationDifferent computational methods are employed to evaluate elastic (rotationally summed) integral and differential cross sections for low energy (below about 10 eV) positron scattering off gas-phase C2H2 molecules. The computations are carried out at the static and static-plus-polarization levels for describing the interaction forces and the correlation–polarization contributions are found to be an essential component for the correct...
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Ice Load Characteristics on Floating Photovoltaic Platform
PublicationNowadays, based upon human needs and preferring perpetual types of energy, photovoltaic system (PV) is a suitable alternative and more frequently used in northern countries, which are recently more attracted by solar power. The new floating type of the structure is installed in the water bodies instead of land. One of the main elements in floating photovoltaic structures is the forces imposed on the panels. In the northern regions,...
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Online sound restoration system for digital library applications
PublicationAudio signal processing algorithms were introduced to the new online non-commercial service for audio restoration intended to enhance the content of digitized audio repositories. Missing or distorted audio samples are predicted using neural networks and a specific implementation of the Jannsen interpolation method based on the autoregressive model (AR) combined with the iterative restoring of missing signal samples. Since the distortion...
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Double-diffusive natural convection energy transfer in magnetically influenced Casson fluid flow in trapezoidal enclosure with fillets
PublicationThe prime motive of this disquisition is to deal with mathematical analysis of natural convection energy transport driven by combined buoyancy effects of thermal and solutal diffusion in a trapezoidal enclosure. Casson fluid rheological constitutive model depicting attributes of viscoelastic liquids is envisioned. The influence of the inclined magnetic field governed by Lorentz field law is also considered. To raise the essence...
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An Analysis of Elliptical-Rectangular Patch Structure on Multilayer Elliptic Cylinders
PublicationThe resonance frequency problem of an ellipticalrectangular patch mounted on multilayered dielectric coated elliptic conducting cylinder, is investigated in this paper. A fullwave analysis and a moment-method calculation are employed. The analysis is carried out considering the expansion of the field as a series of Mathieu functions. An additional theorem for Mathieu functions is utilized to investigate the non-confocal ellipse...
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An Analysis of Multistrip Line Configuration on Elliptical Cylinder
PublicationA configuration of multistrip lines mounted on a multilayer dielectric coated elliptic cylinder is investigated in this paper. A full-wave analysis and a moment-method calculation are employed. The analysis is carried out considering the expansion of the field as a series of Mathieu functions. Both open and shielded lines are considered in the analysis. Propagation coefficients and characteristic impedances are calculated for the...
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Curlicues generated by circle homeomorphisms
PublicationWe investigate the curves in the complex plane which are generated by sequences of real numbers being the lifts of the points on the orbit of an orientation preserving circle homeomorphism. Geometrical properties of these curves such as boundedness, superficiality, local discrete radius of curvature are linked with dynamical properties of the circle homeomorphism which generates them: rotation number and its continued fraction...
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Discussion on “Coupled effective stress analysis of insertion problems in geotechnics with the Particle Finite Element Method” by L. Monforte, M. Arroyo, J.M. Carbonell, and A. Gens
PublicationAddressed here is the Particle Finite Element Method (PFEM) modelling of undrained CPTu penetration with regard to a reference analytical solution based on the Spherical Cavity Expansion Method (SCEM). Also discussed is the choice of the soil model and its parameters. The effect of cone interface friction on CPTu simulation is analyzed in a series of penetration tests using Arbitrary Lagrangian-Eulerian (ALE) and Updated Lagrangian...
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Acinar adenocarcinoma of prostate - Male, 74 - Tissue image [3230630012578991]
Open Research DataThis is the histopathological image of PROSTATE GLAND tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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Online sound restoration system for digital library applications.
PublicationAudio signal processing algorithms were introduced to the new online non-commercial service for audio restoration intended to enhance the content of digitized audio repositories. Missing or distorted audio samples are predicted using neural networks and a specific implementation of the Jannsen interpolation method based on the autoregressive model (AR) combined with the iterative restoring of missing signal samples. Since the distortion...
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Effect of composition on the thermal properties and structure of M-Al-Si-O-N glasses, M = Na, Mg, Ca
PublicationThe primary objective of this study is to explore the relationship between the composition, structure, and thermal characteristics of M-Al-Si-O-N glasses, with M representing sodium (Na), magnesium (Mg), or calcium (Ca). The glasses were prepared by melting in a quartz crucible at 1650 °C and AlN precursor (powder) was utilized as a nitrogen source. The measured thermal properties studied were glass transition temperature (Tg),...