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Search results for: GEOMETRICAL DISPASION
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Znaczenie różnorodności w wirtualnej współpracy
PublicationRóżnorodność jest jedną z podstawowych cech zespołów wirtualnych. Odnosi się ona do geograficznego rozproszenia członków zespołu, różnic stref czasowych, w których pracują, zróżnicowania narodowogo i kulturowego, ale również do pracy dla różnych organizacji, pełnienia różnych ról zespołowych o odpowiedzialności za różne części realizowanego projektu. Artykuł dotyczy najważniejszych wymiarów różnorodności istotnych dla wirtualnej...
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The use of Response Surface Methodology for reliability estimation of aluminum silo subjected to wind load
PublicationAn axisymmetric aluminum silo model with a single, standardized geometric imperfection of its lateral surface is considered. The silo is wind – loaded only. The paper is focused on the critical, or limit value of wind pressure, both producing a loss of stability of the silo. This value is affected by vertical coordinate (position) of the imperfection and the angular relation between the imperfection and the wind direction. Reliability...
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(-4,4'-Bipyridyl-2N:N')bis[bis(tri-tert-butoxysilanethiolato-2S,O)cadmium(II)] toluene disolvate
PublicationW strukturze tytułowego kompleksu znajdują się oddzielne cząsteczki, w których każdy atom kadmu jest koordynowany przez dwa atomy siarki, dwa atomy tlenu i jeden atom azotu. Geometria każdego z atomów kadmu jest pośrednia pomiędzy piramidą o podstawie kwadratu a bipiramidą trygonalną. Dwie jednostki tri-tert-butoksysilanotiolanu kadmu są połączone cząsteczką 4,4'-bipirydylu. Dodatkowo w strukturze kompleksu znajduje się cząsteczka...
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Sztuka i matematyka -algorytmiczne i parametryczne detale
PublicationOpracowanie dotyczy wykorzystania komputerowych metod obliczeniowych do projektowania dzieł architektonicznych, w których geometria formy, detal struktury i efekty materiałowe są wynikiem spójnej reguły generatywnej. Nowatorskie biura tworzą własne narzędzia na poziomie języków programowania czerpiąc idee z abstrakcyjnych koncepcji i procedur matematycznych. W konsekwencji algorytmiczne i parametryczne strategie projektowania w...
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Stability and load bearing capacity of a truss with elastic braces
PublicationThe present paper is devoted to the numerical and experimental investigations of stability of a truss stiffened by elastic braces. The model of a real roof truss scaled by factor ¼ was investigated. In the research the linear buckling and non-linear static analysis of the truss shell and beam model with geometric and material non-linearity is presented. The initial imperfections were assumed in the form of the first buckling mode....
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Asymptotic behaviour in the set of nonhomogeneous chains of stochastic operators
PublicationWe study different types of asymptotic behaviour in the set of (infinite dimensional) nonhomogeneous chains of stochastic operators acting on L1(μ) spaces. In order to examine its structure we consider different norm and strong operator topologies. To describe the nature of the set of nonhomogeneous chains of Markov operators with a particular limit behaviour we use the category theorem of Baire. We show that the geometric structure...
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Comparison of anti-plane surface waves in strain-gradient materials and materials with surface stresses
PublicationHere we discuss the similarities and differences in anti-plane surface wave propagation in an elastic half-space within the framework of the theories of Gurtin–Murdoch surface elasticity and Toupin–Mindlin strain-gradient elasticity. The qualitative behaviour of the dispersion curves and the decay of the obtained solutions are quite similar. On the other hand, we show that the solutions relating to the surface elasticity model...
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INFLUENCE OF NANOPARTICLE CONCENTRATION ON THERMAL PROPERTIES OF THERMAL OIL-MWCNT NANOFLUID
PublicationThis paper deals with measurements of dynamic viscosity, thermal conductivity, electrical conductivity and pH of thermal oil-MWCNT (TO-MWCNT) nanofluid. Nanoparticles were tested at the concentration of 0.001%, 0.005%, 0.01%, 0.05%, and 0,1% by weight. Ultrasonic vibration was used in order to stabilize the dispersion of the nanoparticles. Thermal oil (TO) was selected as a base liquid, because of possible application in ORC systems...
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Preparation of methanation catalysts for high temperature SOEC by β-cyclodextrin-assisted impregnation of nano-CeO2 with transition metal oxides
PublicationThe aim of this work was to prepare and examine the catalytic activity of nanometric CeO2 decorated with transition metal oxides – Ni, Co, Cu, Fe and Mn – towards a high-temperature methanation process under SOEC CO2/H2O simulated co-electrolysis conditions. Samples were prepared using the wet impregnation method via the conventional process and with the addition of native cyclodextrin. The influence of β-cyclodextrin (βCD) onto...
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Thermo-elastic non-linear analysis of multilayered plates and shells
PublicationGeometrically nonlinear FEM analysis of multilayered composite plates and shells is performed in order to resolve the stability problem of the structures being under the influence of temperature field. The Riks-Wempner-Ramm algorithm with a specially modified multi-choice unloading condition has been implemented in authors’ numerical code. As the representation of multilayered medium the Equivalent Single Layer approach with the...
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Arc-length Algorithm Efficiency in the Analysis of Thermally Loaded Multilayered Shells
PublicationThis paper concerns the efficiency study of the arc-length algorithm in the geometrically non-linear analysis of thermally loaded multilayered shells. The thermal loading is considered as the one-way thermo-mechanical coupling effect. Two implementations of the arc-length method are examined: the path-following technique available in NX-Nastran and the RiksWempner-Ramm algorithm adopted in the authors’ computer code SHLTH. It is...
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AKUSTYCZNY ASPEKT ZASTOSOWANIA BLACHY KORTENOWEJ W EUROPEJSKIM CENTRUM SOLIDARNOŚCI W GDAŃSKU
PublicationArtykuł opisuje użycie blachy kortenowej jako dominującego materiału wykończeniowego na elewacjach i we wnętrzach budynku o przesłaniu symbolicznym. Przedstawiono architektoniczne przesłanki, uzasadniające jednorodność zastosowanego materiału. Na tym tle omówiono wpływ blachy kortenowej na akusty-kę pomieszczeń, wraz z podaniem kroków zaradczych redukujących nadmierną pogłosowość i zwiększających stopień rozproszenia dźwięku. Pozytywnym...
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Extending transition curve in analytical design method
PublicationThe paper presents the problem of extending the transitional curves, using for this purpose an analytical design method. The basis for the analysis of numerical calculations were carried out for a wide set of parameters characterizing the standard geometric system. We considered an importance of the size of radius of the circular arc and return angle of route on the obtained results after the formulation of appropriate theoretical...
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The TEMPUS PROGRAM - Computational Geometry for Ships i.e. our first step towards the European Union.
PublicationPraca prezentuje genezę, zakres merytoryczny i realizację europejskiego programu TEMPUS pt. "Geometria Komputerowa dla Statków" zorganizowanego i przeprowadzonego na Wydz. OiO PG w latach 1993-95. Projekt miał charakter dydaktyczny i oferował zaawansowany kurs nowoczesnej metodologii modelowania geometrycznego i analizy hydrodynamicznej kształtu kadłuba okrętu dla studentów wydziału i młodych inżynierów polskiego przemysłu okrętowego....
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Założenia metodyczne i rozwiązania warsztatowe multimedialnego skryptu do geometrii wykreślnej
PublicationMultimedialne techniki przekazu i odbioru informacji odgrywają coraz większą rolę w różnych formach kształcenia. Artykuł porusza zagadnienia związane z konstruowaniem i oceną elektronicznego skryptu do geometrii wykreślnej. Kolejno omówiono cztery fazy tworzenia multimedialnego podręcznika, a mianowicie: przygotowawczą, projektowania, wykonywania materiałów oraz fazę doskonalenia.
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Residence time distribution in rapid multiphase reactors
PublicationResidence time distribution (RTD) provides information about average hydraulic residence time and the distribution of material in the reactor. A method for determining RTD for reactors with very short hydraulic residence times is deconvolution based on extraction of real RTD by the analysis of a non-ideal input signal. The mean residence time and dispersion were determined for the spinning fluids reactor (SFR). For the first time...
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On the Nonlinea Distortions of Sound and its Coupling with Other Modes in a Gasesous Plasma with Finite Electric Conductivity in a Magnetic Field
PublicationNonlinear phenomena of the planar and quasi-planar magnetoacoustic waves are considered. We focus on deriving of equations which govern nonlinear excitation of the non-wave motions by the intense sound in initially static gaseous plasma. The plasma is treated as an ideal gas with finite electrical conductivity permeated by a magnetic field orthogonal to the trajectories of gas particles. This introduces dispersion of a flow. Magnetoacoustic...
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Electromagnetic Modeling of Microstrip Elements Aided with Artificial Neural Network
PublicationThe electromagnetic modeling principle aided withartificial neural network to designing the microwave widebandelements/networks prepared in microstrip technology is proposedin the paper. It is assumed that the complete information is knownfor the prototype design which is prepared on certain substratewith certain thickness and electric permittivity. The longitudinaland transversal dimensions of new design...
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Międzymiasto: Nowa formuła ładu przestrzennego trefy podmiejskiej
Publication.
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Surface effects of network materials based on strain gradient homogenized media
PublicationThe asymptotic homogenization of periodic network materials modeled as beam networks is pursued in this contribution, accounting for surface effects arising from the presence of a thin coating on the surface of the structural beam elements of the network. Cauchy and second gradient effective continua are considered and enhanced by the consideration of surface effects. The asymptotic homogenization technique is here extended to...
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Installation of GNSS receivers on a mobile railway platform – methodology and measurement aspects
PublicationDetermining the course of a railway track axis using satellite methods relies on ensuring the precise assembly of GNSS receivers in dedicated measuring devices. Depending on the number of receivers, solutions that are based on placing the apparatus directly above the railway track axis (as well as in eccentric positions) are used to indirectly obtain data to form the basis of the desired results. This publication describes the...
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Topological modifications for performance improvement and size reduction of wideband antenna structures
PublicationCompact antennas belong to the key components of modern communication systems. Their miniaturization is often achieved by introducing appropriate topological changes such as simple ground plane slots or tapered feeds. More sophisticated modifications are rarely considered in the literature because they normally lead to significant increase of the number of tunable parameters, which makes the antenna design process more challenging....
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On the application of magnetoelastic properties measureme nts for plastic level determination in martensitic steels
PublicationThe change in the dislocation density, induced by plastic deformation, influences strongly the magnetic domain structure inside the material. Being so, classic parameters, like the coercivity or magnetic permeability, can be a good measure of the deformation level, yet their reliable determination in a non-destructive way in industrial environment is problematic. The magnetoacoustic emission (MAE) which results from the non-180...
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The influence of microjet array area ratio on heat transfer in the compact heat exchanger
PublicationThe paper describes the comprehensive study on the effect of microjet array geometrical parameters on the heat transfer enhancement in the modular heat exchanger. The conducted experimental study provides an experimental database on single phase submerged microjet heat transfer. The Wilson plot method was applied to determine the heat transfer coefficients in the laminar and transition flow regimes of a liquid-to-liquid heat exchanger....
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Controlled Random Search Applied to Parameters Estimation of the Longitudinal Solutes Transport Model for Rivers
PublicationNumerical computations are presented for the longitudinal transport of passive, conservative solutes in an actual river with the inclusion of geometrical complexities of river channels. A special emphasis is put on the method of the identification of model parameters which is based on a specially designed optimisation procedure using random control search algorithm. Two different situations are considered namely a linear version...
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Applicability of arrays of microjets heat transfer correlations to design compact heat exchangers
PublicationThe article presents experimental studies on a compact heat exchanger with heat transfer intensification by means of impinging microjets. The pursuit to provide high performance of heat exchangers is a response to the demand both in economics and in the universal tendency to miniaturization of industrial equipment. This paper presents the design and tests of a prototype, microjet heat exchanger. The modular design of the heat exchanger...
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Edgewise Compressive Behavior of Composite Structural Insulated Panels with Magnesium Oxide Board Facings
PublicationEdgewise compression response of a composite structural insulated panel (CSIP) with magnesium oxide board facings was investigated. The discussed CSIP is a novel multifunctional sandwich panel introduced to the housing industry as a part of the wall, floor, and roof assemblies. The study aims to propose a computational tool for reliable prediction of failure modes of CSIPs subjected to concentric and eccentric axial loads. An advanced...
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On weak solutions of the boundary value problem within linear dilatational strain gradient elasticity for polyhedral Lipschitz domains
PublicationWe provide the proof of an existence and uniqueness theorem for weak solutions of the equilibrium problem in linear dilatational strain gradient elasticity for bodies occupying, in the reference configuration, Lipschitz domains with edges. The considered elastic model belongs to the class of so-called incomplete strain gradient continua whose potential energy density depends quadratically on linear strains and on the gradient of...
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Improvement of the Chimney Effect in Stack Ventilation
PublicationThe article is focused on the airflow in a ventilation system in a building. The work examines the methods which enhance the chimney effect. In this paper, three cases with different chimneys were analyzed for the full-scale experiment. These cases were characterized by different geometrical and material parameters, leading to differences in the intensity of the ventilation airflow. The common denominator of the cases was the room...
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On Decomposition-Based Surrogate-Assisted Optimization of Leaky Wave Antenna Input Characteristics for Beam Scanning Applications
PublicationRecent years have witnessed a growing interest in reconfigurable antenna systems. Travelling wave antennas (TWAs) and leaky wave antennas (LWAs) are representative examples of structures featuring a great level of flexibility (e.g., straightforward implementation of beam scanning), relatively simple geometrical structure, low profile, and low fabrication cost. Notwithstanding, the design process of TWAs/LWAs is a challenging endeavor...
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MORPHOLOGY OF BUILDING DEVELOPMENT AS AN ELEMENT OF URBAN VENTIALTION SYSTEM
PublicationProblems related to air quality in large urban agglomerations (e.g., high concentration of pollutants, the urban heat island phenomenon) make it necessary to take comprehensive measures to improve air exchange in urban areas.The article concerns the relationship between wind phenomena observable in cities and the geometrical features of building development. The knowledge on the subject is already well-founded and has been intensively...
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Stability of an imperfect truss loaded by wind
PublicationThe present paper is devoted to the numerical research of stability of a truss loaded by wind and stiffened by elastic supports located at the top chord. The lateral braces or lateral and torsional braces were taken into account. In this paper, the linear buckling analysis re- sults for the beam and shell model were presented. Two different shapes of initial geometric imperfections were considered in the non-linear static analysis...
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Inexpensive Helical Antenna for Global Navigation Satellite Systems
PublicationZaprezentowane zostały wyniki badań teoretycznych oraz eksperymentalnych niskobudżetowej anteny na pasmo L. Wyjściowa geometria struktury została obliczona na podstawie ogólnych wzorów. Efekt przesunięcia częstotliwości wywołany przez użycie rdzenia PU został również uwzględniony. Równolegle przeprowadzono badania wrażliwości parametrów anteny na proces produkcji. Zaprojektowano i wykonano układ dopasowania impedancyjnego. W paśmie...
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(μ2-4,4'-Bipyridyl-κ2N:N')bis[bis(tri-tert-butoxysilanothiolato- κ2S,O)cadmium(II)] tetrahydrofuran disolvate
PublicationW strukturze tytułowego kompleksu znajdują się oddzielne cząsteczki, w których każdy atom kadmu jest koordynowany przez dwa atomy siarki, dwa atomy tlenu i jeden atom azotu. Geometria każdego z atomów kadmu jest pośrednia pomiędzy piramidą o podstawie kwadratu a bipiramidą trygonalną. Dwie jednostki tri-tert-butoksysilanotiolanu kadmu są połączone cząsteczką 4,4'-bipirydylu. Dodaktowo w strukturze kompleksu znajdują się dwie cząsteczki...
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(2-Ethylimidazole-κN)bis(tri-tert-butoxysilanethiolato-κ2O,S)zinc(II) propan-2-ol solvate
PublicationW publikowanym związku [Zn(C12H27O3SSi)2(C5H8N2)]*C3H8O, atom Zn(II) jest koordynowany przez atom azotu 2-etyloimidazolu, dwa atomy siarki i dwa atomy tlenu pochodzące od reszt tri-tert-butoksysilanotiolanowych, a geometria na atomie cynku(II) jest typu trygonalnej bipiramidy. Grupa hydroksylowa cząsteczki rozpuszczalnika 2-propanolu tworzy dwa wiązania wodorowe typu N-H - O i O-H - S z sąsiednią czasteczkĄ kompleksu, przez co...
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n-butyl 2-(3-chloro-1,2-dihydropyrazin-2-ylidene)-2-cyanoacetate
PublicationStrukturę C11H12ClN3O2 wyznaczono metodą rentgenowskiej analizy strukturalnej. Geometria i długości wiązań w pierścieniu pirazynowym są typowe dla tej klasy związków. Cała cząsteczka, poza ogonem n-butylowym, jest płaska (r.m.s. 0.0131(1)Å). Występujące intramolekularne wiązanie wodorowe N2-H2BO1 tworzy S(6) pierścień stabilizując całą cząsteczkę. W sieci krystalicznej obserwuje się nieuporządkowanie statyczne dla reszty...
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The decay of quantum correlations between quantum dot spin qubits and the characteristics of its magnetic-field dependence
PublicationWe address the question of the role of quantum correlations beyond entanglement in the context of quantum magnetometry. We study the evolution of the rescaled variant of the geometric quantum discord of two electron-spin qubits interacting with an environment of nuclear spins via the hyperfine interaction. We have found that quantum correlations display a strong magnetic-field sensitivity which can be utilized for decoherence-driven...
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Analysis of sloping brace stiffness influence on stability and load bearing capacity of a truss
PublicationThe paper is focused on the numerical study of stability and load bearing capacity of a truss with side elastic braces. The structure is made in reality. The rotational and sliding brace stiffnesses were taken into account. Linear buckling analysis and non-linear static analysis with geometric and material nonlinearity were performed for the beam and shell model of the truss with respect to the angle of sloping braces. As a result...
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Shaping of the turnout diverging track with variable curvature sections
PublicationThe paper presents an analytical method of shaping the turnout diverging railroad track with variable curvature segments on its length, which in an evident way distinguished it from a typical solution, made up of a single circular arc with no transition curves. Two separate causes including a linear and a nonlinear curvature one in the form of a polynomial have been examined. The obtained solutions of the problem have a universal...
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The power of silence? opinion contagion and the surprise of the polish 2005 parlamentary and presidential elections
PublicationThis paper investigates opinion contagion in collective behaviour using threshold model (Granovetter (1978), Krassa(1988)). The theoretical background is the spiral of silence concept developed by Noelle-Neumann (1974), arguing that people only assert their opinions if they perceive a minimal support from a relevant proportion of others. We apply the model to explain the dispersion between pre-elections preferences and the final...
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The Implementation of the Taxonomic Spatial Measure of Development in the Analysis of Convergence in the Standard of Living
PublicationThe main goal of this paper is to analyse the existence of the social convergence in the European Union between 19952012. The social convergence refers to a reduction in the dispersion of the standard of living across countries. A taxonomic spatial measure of development was used as the standard of living approximation. The use of the new approach proposed by E. Antczak allowed for an explanation of the disparities in the analysed...
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Robust estimation of deformation from observation differences for free control networks
PublicationDeformation measurements have a repeatable nature. This means that deformation measurements are performed often with the same equipment, methods, geometric conditions and in a similar environment in epochs 1 and 2 (e.g., a fully automated, continuous control measurements). It is, therefore, reasonable to assume that the results of deformation measurements can be distorted by both random errors and by some non-random errors, which...
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Research project BRIK: development of an innovative method for determining the precise trajectory of a railway vehicle
PublicationIn the paper the essential assumptions regarding a research project implemented by a consortium of Gdansk University of Technology and Gdynia Maritime University are presented. The project has been commissioned by National Center of Research and Development with cooperation with Polish Railways (PKP Polskie Linie Kolejowe S.A.). The project is focused in implementation of modern measurement techniques using Global Navigation Positioning...
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A New Adaptive Method for the Extraction of Steel Design Structures from an Integrated Point Cloud
PublicationThe continuous and intensive development of measurement technologies for reality modelling with appropriate data processing algorithms is currently being observed. The most popular methods include remote sensing techniques based on reflected-light digital cameras, and on active methods in which the device emits a beam. This research paper presents the process of data integration from terrestrial laser scanning (TLS) and image data...
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Friction Stir Welding of Aluminum in the Aerospace Industry: The Current Progress and State-of-the-Art Review
PublicationThe use of the friction stir welding (FSW) process as a relatively new solid-state welding technology in the aerospace industry has pushed forward several developments in different related aspects of this strategic industry. In terms of the FSW process itself, due to the geometric limitations involved in the conventional FSW process, many variants have been required over time to suit the different types of geometries and structures,...
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REINFORCED CONCRETE SUPPORTING CONSTRUCTION OF THE STADIUM COVER FOR EURO 2012 IN GDAŃSK
PublicationIn the article structural issues that connected with the reinforced concrete supporting construction of the stadium roofing for EURO 2012 in Gdańsk were described. In the first part of the article the concept of stadium foundation were described. In the second the static - strength analysis for two variants fastening together individual foundation elements were made. The two assumed geometrically different concept of foundation...
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Postquarter-Point Case of Ship’s Side-Berthing and Its Influence on Marine Fender Pitch
PublicationThis paper presents a critical analysis of some selected codes and practical recommendations used as basic rules in the design procedures of modern marine fender systems. The first part of the discussion pertains to the existing equations used in calculating the eccentricity coefficient in the ship’s kinetic energy equation and the maximum allowable fender pitch (spacing) in a set of fenders installed along a quay wall. A new approach...
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INNOVATIVE THERMODYNAMICAL CYCLES BASED ON ENHANCEMENT MASS, MOMENTUM, ENTROPY AND ELECTRICITY TRANSPORT DUE TO SLIP, MOBILITY, TRANSPIRATION, ENTROPY AND ELECTRIC JUMPS AS WELL AS OTHER NANO-FLOWS PHENOMENA
PublicationIn our work, a further development of the authors model of thermo-chemical flow of fuel, air, oxygen, steam water, species, ionic and electron currents within nano channels and nano-structures of novel devices is presented. Different transport enhancement models are taken into account -among them the most important are: the velocity slip connected with complex external friction, the Darcy mobility and the Reynolds transpiration....
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Mechanical analysis of eccentric defected bilayer graphene sheets considering the van der Waals force
PublicationIn this article, we have tried to simulate nonlinear bending analysis of a double-layered graphene sheet which contains a geometrical imperfection based on an eccentric hole. The first-order shear deformation theory is considered to obtain the governing equations. Also, the nonlinear von Kármán strain field has been assumed in order to obtain large deformations. Whereas the double-layered graphene sheet has been considered, the...
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Nonlinear Modeling in Time Domain Numerical Analysis of Stringed Instrument Dynamics
PublicationMusical instruments are very various in terms of sound quality with their timbre shaped by materials and geometry. Materials' impact is commonly treated as dominant one by musicians, while it is unclear whether it is true or not. The research proposed in the study focuses on determining influence of both these factors on sound quality based on their impact on harmonic composition. Numerical approach has been chosen to allowed independent...