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Search results for: investigation of structures elements
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THE USE OF GREEN LOGISTICS ELEMENTS DURING THE CONSTRUCTION OF OFFSHORE VESSELS
PublicationThe article is aimed at the presentation referring to the use of green logistics elements during the construction of the offshore vessels in the following aspects: collection, removal and utilisation of any waste that is harmful for natural environment, elimination of the negative impact that such waste can have on natural environment and the search for the optimal solutions as regards these aspects.
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Global defensive secure structures
PublicationLet S ⊂ V (G) for a given simple non-empty graph G. We define for any nonempty subset X of S the predicate SECG,S(X) = true iff |NG[X]∩S| ≥ |NG[X]\S|. Let H be a non-empty family of graphs such that for each vertex v ∈ V (G) there is a subgraph H of G containing v and isomorphic to a member of H. We introduce the concept of H-alliance extending the concept of global defensive secure structures. By an H-alliance in a graph G we...
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Guided waves for monitoring of plate structures with linear cracks of variable length
PublicationDamage occurring at the work of plate structures may grow to a considerable size. The joint action – the detection of a defect at the earliest possible stage, the monitoring of its growth and the determination of its critical size in the context of structural reliability allows optimizing the cost of the maintenance and repair of structural elements. Thus the development of monitoring systems for permanent observation of fault...
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Investigation of hydrodynamic clutch with a magnetorheological fluid
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Experimental study on polymer mass used to repair damaged structures
PublicationA new method of repairing damaged structures by injecting the cracks with specially designed polymer mass (flexible two-component grout based on polyurethane resin) has been recently proposed. The technique is mainly dedicated to damaged masonries, especially historical structures where minimum intervention is permitted. The cracks are filled with the special injection, forming the flexible joints bonding the disrupted structural...
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Determinants of export diversification: an empirical investigation
PublicationEmpirical findings confirm that relatively high specialisation of economic structures tends to be associated with low levels of income per capita, but countries diversify their export structures along their path of growth. However, usually only per capita income, and eventually, country-specific fixed effects are the sole explanatory variables taken into consideration in the estimation of specialisation curves. We extend the analysis...
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Failure model of main elements of the ship engine crankshaft-piston assembly
PublicationThe paper presents a failure model of main elements of the crankshaft-piston assembly, based on failures ofcrankshaft-piston assembly and timing gear system of the Sulzer RD engines, retrieved from the equipment reliabilitydata of selected ships.
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Rigid finite elements and multibody modelling used in estimation and reduction of rod vibrations
PublicationIn the paper, a mechanical set composed of a robot (manipulator) and of an elastic beam is considered. The beam is fixed to the top of the robot structure. In most of the similar cases, undesired vibrations can be excited in the beam. They are especially significant, when dynamics in the robot braking period is examined. In the paper, estimation and modification of length of the braking period is proposed, in order to reduce the...
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Database for integration of information in distributed data exchange system elements of Border Guard
PublicationThe paper presents the database solution for integration of information in distributed data exchange system elements of the Polish Border Guard. The proposed database solution is described in the context of data exchange system elements which control position and store identification data of vessels (fishing, sports and sailing boats) and other suspicious objects on the territorial sea, sea-coast and the internal sea-waters controlled...
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RARE-EARTH ELEMENTS DOPING OF BARIUM CERATE AND ZIRCONATE SOLID SOLUTION
PublicationThe properties of doped barium cerate barium zirconate solid solution are presented in presented work. It was found that doping of solid solution of barium cerate and zirconate by rare-earth elements have an influence on microstructure and electrical properties of the samples.
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Investigation of the aerodynamics of an innovative verticalaxis wind turbine
PublicationThis paper presents a preliminary three dimensional analysis of the transient aerodynamic phenomena occurring in the innovative modification of classic Savonius wind turbine. An attempt to explain the increased efficiency of the innovative design in comparison with the traditional solution is undertaken. Several vorticity measures such as enstrophy, absolute helicity and the integral of the velocity gradient tensor second invariant...
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Selective Laser Melting of Ti Alloy for Manufacturing The Prosthetic Elements
PublicationThe selective laser melting (SLM) is the additive manufacturing method of custom-designed parts. The used materials and the applications are various, including medicine. The titanium and its alloys are materials for which the dimensional quality, surface smoothness and no or extremely low porosity are difficult to reach. In this paper, the successful attempt to obtain by SLM the individually designed prosthetic bridges is described....
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Support for argument structures review and assessment
PublicationArgument structures are commonly used to develop and present cases for safety, security and for other properties of systems. Such structures tend to grow excessively, which causes problems with their review and assessment. Two issues are of particular interest: (1) systematic and explicit assessment of the compelling power of an argument, and (2) communication of the result of such an assessment to relevant recipients. The paper...
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Numerical analysis of elastic wave propagation in unbounded structures
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Earthquake–induced pounding on response of adjacent structures in series: experimental and numerical study
PublicationPounding between structures in series during earthquakes may cause serious damage in the structur-al elements. The aim of this paper is to show the results of an experimental and numerical study that is focused on pounding between more than two structures which may be called "structures in series". In this study, the shaking table experiments, as well as the numerical analyses, were performed using three tower models including...
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Comparison of Surface Quality and Tool-Life of Glulam Window Elements after Planing
PublicationThe quality of the surface of wooden elements, that have been planed, has a crucial importance in the whole production process, since the obtained effects affect the quality of wooden surface after fi nishing (painting). The occurrence of defects is usually the reason for qualifying a workpiece as scrap or for requiring additional work. This paper presents the selected results of research of the effect of the cutting tool wear...
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Recent steel structures in Poland - the selected projects
PublicationThe paper presents selected examples of recently completed steel structures in Poland. These are roofs over sport stadiums, construction of public buildings and bridges. Described examples do not exhaust the acquis in the field of steel constructions in Poland. The authors, however, may hope that the presented con-structions represents current achievements in Poland in the field of steel structures.
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Shaping the spatial structures of post-socialist cities
PublicationThis paper deals with issues and problems associated with transformation of spatial structures of post-socialist cities. The special attention is paid to the cases of Polish cities and towns and the analysis of their evolution – from the “post-communist structures” to the “cities in the age of globalization”. In the light of this the factors influencing the spatial transformation of these are analyzed. The paper is concluded with...
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Controlling nodal displacement of pantographic structures using matrix condensation and interior-point optimization: A numerical and experimental study
PublicationThis study presents an innovative approach for the precise control of nodal displacements in pantographic structures. The method is founded on the Matrix Condensation of Force Method, seamlessly integrated with an Interior Point Optimization algorithm. This combination offers a unique advantage by allowing users to manipulate displaced nodes within a defined coordination domain. Furthermore, this approach introduces the Interior...
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Selected Aspects of 3D Printing for Emergency Replacement of Structural Elements
PublicationThe paper presents a synthetic characterization of modern methods of manufacturing or regenerating machine elements. Considered methods are machining and additive methods, in particular 3D printing in the FDM/FFF technique. For the study, the authors made samples of the holder bracket using selected methods. Samples made by machining operations, 3D printing with various filling were tested. The paper contains a technical and economic...
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Remote sensing in laboratory diagnostics of reinforced concrete elements – current development and vision for the future
PublicationContinuous emergence of new concrete types and kinds of reinforcement, as well as technological solutions in the field of structural engineering have made great demand for diagnostic tests of reinforced concrete elements. New challenges and problems facing people require new more efficient tools for laboratory diagnostics than those commonly used. Remote sensing may be the answer to this demand. In this paper the author describes...
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Remote sensing in laboratory diagnostics of reinforced concrete elements – current development and vision for the future
PublicationContinuous emergence of new concrete types and kinds of reinforcement, as well as technological solutions in the field of structural engineering have made great demand for diagnostic tests of reinforced concrete elements. New challenges and problems facing people require new more efficient tools for laboratory diagnostics than those commonly used. Remote sensing may be the answer to this demand. In this paper the author describes...
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Generalized Taylor formula and shell structures for the analysis of the interaction between geosythetics and engineering structures of transportation lines
PublicationThe analysis of the interaction between geosynthetics and engineering structures (e.g. railroad bed, soil foundation, pipeline) assumes that the geosynthetic form elastic membranes or shell laid on different types of foundations. The mathematical description of that problems in continuous domain employs Laplace operator Δ or d’Alembert operator □. In this paper we demonstrate the analysis based on generalize Taylor formula, and...
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Experimental investigation of joint with positive eccentricity in CFS truss
PublicationDue to technological restrictions, in the case of trusses made of CFS open cross-sections, positive eccentricities in the truss joints have become very frequent. Therefore studies concerning the load-bearing capacity of truss joints with positive eccentricity were undertaken. It was assumed that the resistance of cold-formed steel (CFS) open cross-section truss joints located on compression chords and with positive eccentricity...
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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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Light box for investigation of characteristics of optoelectronics detectors
PublicationIn this paper, a light box for investigation of characteristics of optoelectronic detectors is described. The light box consists of an illumination device, an optical power sensor and a mechanical enclosure. The illumination device is based on four types of high-power light emitting diodes (LED): white light, red, green and blue. The illumination level can be varied for each LED independently by the driver and is measured by optical...
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Fracture simulations in concrete beam under bending using a mesoscopic model with cohesive elements
PublicationThe main aim of this paper was to investigate a complex fracture process in a concrete beam subjected to 3-point bending test by means of the 2D meso-scale FEM with 4-node cohesive elements embedded in the initial mesh of 3-node solid elements. The material heterogeneity was taken into account by considering 3 different phases (aggregate, cement matrix, ITZs) on the basis of randomly generated internal structure of concrete and...
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Determination of Elements in Fruit Juices
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Al203 sealing elements lapping
PublicationPrzedstawiono wyniki badań własnych wydajnosci docierania ceramiki Al203. Badano elementy uszczelniające na docierarce jednotarczowej o standardowym układzie kinematycznym. Określono wpływ wielkości mikroziaren węglika boru o numerze F400/17, F800/6.5 i F1200/3 oraz wartości nominalnego nacisku jednostkowego na ubytek materiału w czasie 15 i 20 min. Scharakteryzowano mechanizm usuwania naddatku przy docieraniu elementów ceramicznych....
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Hybrid Analysis of Structures Composed of Axially Symmetric Objects
Publication— A hybrid method for the scattering problems in shielded and open structures is presented. The procedure is based on the combination of body-of-revolution involving finite-element methods with impedance matrix formulation and the mode-matching technique, which can be utilized for the analysis of structures with axially symmetrical scatterers. In order to confirm the validity and efficiency of the proposed approach, a few examples...
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VIBRATION PARAMETERS FOR DAMAGE DETECTION IN STRUCTURES
PublicationThe aim of this paper is to examine how damage indicators are sensitive to changing number of frequencies and mode shapes and also to number and location of measurement points. The influence of measurement errors was also analyzed for all cases. For the analysis, those damage indicators are chosen which use changes in such modal parameters as natural frequencies and mode shapes and also differences between the curvatures of the damaged...
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Raman spectroscopic investigation of blood and related materials
PublicationThis paper reports preliminary studies on use of Raman spectroscopy for investigation of blood. High quality blood spectra were recorded in-vitro with excitation wavelengths of 830 nm. Because of complex composition of the blood as well as by light attenuation and scattering in the tissues, spectra set up from wide, low-intensive Raman bands and intensive optical background. To get information about origin of bands in Raman spectra...
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Minimal surfaces and conservation laws for bidimensional structures
PublicationWe discuss conservation laws for thin structures which could be modeled as a material minimal surface, i.e., a surface with zero mean curvatures. The models of an elastic membrane and micropolar (six-parameter) shell undergoing finite deformations are considered. We show that for a minimal surface, it is possible to formulate a conservation law similar to three-dimensional non-linear elasticity. It brings us a path-independent...
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Role of public space in designing complex urban structures
PublicationThe aim of this article is to present the main assumptions about design studios as held in the Faculty of Architecture at Gdańsk University of Technology (FA-GUT), Gdańsk, Poland, adapted to the development of key competencies in the urban planning of complex urban structures. One of these competencies is the design of public spaces. The main goal of the studios was to deliver knowledge of the role of public spaces in the design...
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SIGNIFICANT GUIDELINE FOR THE DAMAGE INDICES APPLIED TO REINFORCED CONCRETE STRUCTURES
PublicationIn this paper, based on a deep overview and literature study, the different formulas proposed for damage indices (DIs) applied to reinforced concrete structures under monotonic or cyclic loading are classified and presented. The DIs are applied to quantify the damages to structures, ranging from zero to one. Normally, they are applied to make a decision for repairing or demolition of the structures in the post-earthquake phases. Keywords:...
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Robust four-node elements based on Hu–Washizu principle for nonlinear analysis of Cosserat shells
PublicationMixed 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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On a 3D material modelling of smart nanocomposite structures
PublicationSmart composites (SCs) are utilized in electro-mechanical systems such as actuators and energy harvesters. Typically, thin-walled components such as beams, plates, and shells are employed as structural elements to achieve the mechanical behavior desired in these composites. SCs exhibit various advanced properties, ranging from lower order phenomena like piezoelectricity and piezomagneticity, to higher order effects including flexoelectricity...
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Mechanics of Micro- and Nano-Size Materials and Structures
PublicationNanotechnology knowledge is always looking to expand its boundaries to achieve the mostsignificant benefit to human life and meet the growing needs of today. In this case, we can refer tomicro- and nanosensors in micro/nano-electromechanical systems (MEMS/NEMS). These electricaldevices can detect minimal physical stimuli up to one nanometer in size. Today, micro/nano-sensordevices are widely used in the...
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3D porous graphene-based structures- synthesis and applications
PublicationPorous carbon-based materials are of the great industrial and academic interest due to their high surface area, low density, good electrical conductivity, chemical inertness and low cost of fabrication. Up to now, the main approach to obtain porous carbon structures has involved the pyrolysis of carbonaceous natural or synthetic precursors. After the isolation of graphene, the interest in 3D porous graphene-based structures (called...
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Car-sharing: The Impact on Metropolitan Spatial Structures
PublicationMany examples from the past show that new technologies designed to solve particular problems can also create side effects generating new problems. Some unforeseen or unwanted results may influence space use and spatial structures. Car-sharing is an invention to compete with car ownership. It drastically rise efficiency of car use, reducing the number of vehicles per users. Diffusion of car-sharing is going to accelerate in the...
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Galerkin formulations with Greville quadrature rules for isogeometric shell analysis: Higher order elements and locking
PublicationWe propose new Greville quadrature schemes that asymptotically require only four in-plane points for Reissner-Mindlin (RM) shell elements and nine in-plane points for Kirchhoff-Love (KL) shell elements in B-spline and NURBS-based isogeometric shell analysis, independent of the polynomial degree of the elements. For polynomial degrees 5 and 6, the approach delivers high accuracy, low computational cost, and alleviates membrane and...
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Application of gpr method in diagnostics of reinforced concrete structures
PublicationThis paper presents an application of the ground penetration method (GPR) for diagnostics of reinforced concrete structures. In situ measurements were conducted for three civil engineering structures: the ground floor structure, the abutment of the railway viaduct and the concrete well. The dual polarized ground penetrating radar with the antenna operating at a center frequency of 2 GHz was used for GPR surveys. Three different...
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Modular Approach for Modelling Warming Up Process in Water Installations with Flow-Regulating Elements
PublicationThe paper presents a new method for modelling the warming up process of a water system with elements regulating the flow in a stochastic manner. The paper presents the basic equations describing the work of typical elements which the water installation is composed of. In the proposed method, a new computational algorithm was used in the form of an iterative procedure enabling the use of boundary conditions that can be stochastically...
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Modelling of elastic wave propagation in a bolted joint using a thin layer of shell elements
PublicationThere are many mathematical models describing the propagation of elastic waves through the imperfect boundary of two media. They were successfully applied to modelling of high frequency bulk waves and their interaction with local defects. On the other hand, the existing literature models of bolted connections ignore the aspect of imperfect connection between elements. Therefore, this paper presents the concept of application of...
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A proposition for integrating elements of game universe by means of behavioral trees
PublicationModern computer games often involve autonomous beings collaborating and competing with each other to reach their objectives in the game universe. It seems only natural to use agent-oriented approach in such cases. This article identifies the rules of building a game universe as an environment for executing agents. The paper also covers a method for decomposing compound behaviors into behavioral trees. Dividing complex behaviors...
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The FEM analysis of pressure installation elements after simulated accidental overheating
PublicationThe paper presents innovative analysis focused on the safety aspects of existing pressure installation operation after overheating accidents. Results presented here can be applied in decision-making process concerning further operation of existing pressure installation after cooling system failure. In this paper the results of FEM analysis performed for a straight pipe and 90 degrees elbow, made of super duplex stainless steel,...
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Optoelectronic investigation of nanodiamond interactions with human blood
PublicationWe present optoelectronic investigation of in vitro interactions of whole human blood with different nanodiamond biomarkers. Plasmo-chemical modifications of detonation nanodiamond particles gives the possibility for controlling their surface for biological applications. Optical investigations reveal the biological activity of nanodiamonds in blood dependent on its surface termination. We compare different types of nanodiamonds:...
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Predicting the seismic collapse capacity of adjacent structures prone to pounding
PublicationIn crowded cities, many structures are often constructed in a very close vicinity; therefore, during severe earthquakes, pounding phenomenon occurs due to out-of-phase vibrations of adjacent structures. In this study, pounding of adjacent structures is investigated up to the occurrence of total collapse. The novelty of this study is performing incremental dynamic analyses to compute the seismic collapse capacities of both pounding...
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Experimental Study on Pounding between Structures during Damaging Earthquakes
PublicationMutual pounding between structures during earthquakes may cause serious structural damage. The aim of this paper is to show the results of a shaking table experimental study focused on pounding between structures in series under several earthquake excitations. The experiments were performed using three tower models with different configurations and different gap distances between them. In the first stage of the study, one rigid...
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Timber - material of the future. Examples of small wooden architecture structures.
PublicationThe aim of this article is to present various types of wood-based products, classified as engineered timber, while specifying the implications of their structural properties for their forms. Timber is used as a construction material due to its fire resistance, good structural characteristics and insulating properties. The advent of new technologies of wood processing and wood-based materials production has converted timber into...