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Zastosowanie nowatorskich materiałów geosyntetycznych w konstrukcjach oporowych z gruntu zbrojonego
PublikacjaArtykuł prezentuje metodę projektowania stromych skarp wznoszonych z gruntów słabo przepuszczalnych, zbrojonych geosiatkami drenującymi. Z analiz przeprowadzonych dla różnej wodoprzepuszczalności gruntu i różnej geometrii skarpy wynika, że pionowy rozstaw i długość zbrojenia mają istotne znaczenie dla stateczności skarpy. Dla gruntów słabo przepuszczalnych, o typowych wartościach współczynników ściśliwości objętościowej oraz konsolidacji,...
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Micro-cracking pattern recognition of hybrid CNTs/GNPs cement pastes under three-point bending loading using acoustic emission technique
PublikacjaThe generation of microcracks has an important influence on the behaviour of concrete structures. In this study, the acoustic emission (AE) technique was used to investigate the fracture phenomena and micro-cracking behavior of hybrid carbon nanotubes (CNTs, the 1-D allotrope of carbon atoms) and graphene nanoplatelets (GNPs, 2D monolayer of sp2-hybridized carbon atoms), cement composites under three-point bending loading. In...
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Effective Formula for Impact Damping Ratio for Simulation of Earthquake-induced Structural Pounding
PublikacjaStructural pounding during earthquakes may cause substantial damage to colliding structures. The phenomenon is numerically studied using different models of collisions. The aim of the present paper is to propose an effective formula for the impact damping ratio, as a parameter of the impact force model used to study different problems of structural pounding under seismic excitations. Its accuracy has been verified by four various...
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Combination of terrestrial laser scanning and UAV photogrammetry for 3D modelling and degradation assessment of heritage building based on a lighting analysis: case study—St. Adalbert Church in Gdansk, Poland
PublikacjaThe construction of the St. Adalbert Church in Gdansk dates to 1310. It is a church of rich history and great historical value, and its care is challenging. In this study, the combination of unmanned aerial vehicle (UAV) photogrammetry and terrestrial laser scanning (TLS) was used to accurately build a 3D model of the church. Together with the collected historical inventory documentation, the historic building information model...
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Vibro-Electrical Behavior of a Viscoelastic Piezo-Nanowire in an Elastic Substrate Considering Stress Nonlocality and Microstructural Size-Dependent Effects
PublikacjaThis research deals with dynamics response of a Pol/BaTiO3 nanowire including viscosity influences. The wire is also impressed by a longitudinal electric field. Hamilton's principle and Lagrangian strains are employed in conjunction with a refined higher-order beam theory in order to derive equations of motion. By combining nonlocality and small size...
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Numerical analysis of a temporary steel grandstand
PublikacjaThe purpose of this paper is to present the results of the numerical analysis focused on the response of the temporary steel scaffolding grandstand subjected to human-induced vibrations due to jumping. Shell as well as beam elements have been used in the numerical model. Its first stage has involved conducting modal analysis in order to determine the modes of free vibrations and the corresponding natural frequencies for the empty...
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Verification of ESPAR Antennas Performance in the Simple and Calibration Free Localization System
PublikacjaThis paper presents the results of simulations and measurements of an indoor localization system that uses Electronically Steerable Parasitic Array Radiator (ESPAR) antennas with switched directional beam. Proposed antennas are dedicated for 2.4GHz ISM low-cost applications where determination of the incoming signal is required. The antennas performance is analyzed and verified with relation to positioning methods based on the...
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Adhesive compliance effect in mode I separation:Profilometry approach
PublikacjaThe effect of adhesive compliance on the deflection of a loaded, bonded beam was studied using laser profilometry. Experimental data obtained were compared with both Euler-Bernoulli (encastré) and Winkler (one parameter elastic foundation) models. A third, analytical, 2D model, based on shear within the adhesive layer (two parameter elastic foundation), was introduced. Finite element analysis (FEA) was also used to study the effect...
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Formation and Growth of the Crack in Bonded Joints Under Mode I Fracture: Substrate Deflection at Crack Vicinity
PublikacjaAdhesive bonding is now commonly used in aircraft, cars, boats, etc. In these applications, thin panels are often bonded. In such thin structures, heterogeneous mechanical loading along the bondline edge (or potential crack front), is likely to arise due to 3D structural effects. The crack front and its vicinity is a special region, in that it is where structural properties of the adherend material meet those of the adhesive (discontinuity)....
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Properties of Barium Cerate-Zirconate Thin Films
PublikacjaIn this work, we review several experimental results showing the electrical properties of barium cerate-zirconate thin films and discuss them in view of the possible influence of various factors on their properties. Most of the presented Ba(Ce, Zr, Y)O3 thin films were formed by the pulsed laser deposition (PLD) technique, however thin films prepared using other methods, like RF magnetron sputtering, electron-beam deposition, powder...
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Local and global response of sandwich beams made of GFRP facings and PET foam core in three point bending test
PublikacjaIn the paper behaviour of laminated sandwich beams (FRP face sheet – PET foam core – FRP face sheet) subjected to three point bending is studied. The paper aim is to find practical descriptions enabling effective and accurate estimation of the elastic response, damage and failure of the beams, basing on experiments and static calculations. Therefore a number of tests are described, that were done on laminated coupons and foam specimens...
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A DISCRETE-CONTINUOUS METHOD OF MECHANICAL SYSTEM MODELLING
PublikacjaThe paper describes a discrete-continuous method of dynamic system modelling. The presented approach is hybrid in its nature, as it combines the advantages of spatial discretization methods with those of continuous system modelling methods. In the proposed method, a three-dimensional system is discretised in two directions only, with the third direction remaining continuous. The thus obtained discrete-continuous model is described...
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The role of low-energy electrons in the charging process of LISA test masses
PublikacjaThe estimate of the total electron yield is fundamental for our understanding of the test-mass charging associated with cosmic rays in the Laser Interferometer Space Antenna (LISA) Pathfinder mission and in the forthcoming gravitational wave observatory LISA. To unveil the role of low energy electrons in this process owing to galactic and solar energetic particle events, in this work we study the interaction of keV and sub-keV...
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Buckling of simplified models of silo with corrugated walls and vertical stiffeners
PublikacjaThe paper deals with buckling of cylindrical silos composed of corrugated sheets and vertical stiffeners (columns). Comprehensive finite element analyses were carried out for a perfect silo by means of a linear buckling approach. Corrugated walls were simulated as an equivalent orthotropic shell and vertical thin-walled columns as beam elements. Calculations for perfect silos with different numbers of columns made it possible to...
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Validation Process for Computational Model of Full-Scale Segment for Design of Composite Footbridge
PublikacjaExperimental tests and numerical simulations of a full-scale segment of a foot and cycle bridge made of polymer composites are presented in the paper. The analysed structure is made of sandwich panels, which consist of glass fibre reinforced polymer (GFRP) multi-layered laminate faces and a PET foam (obtained from recycling) core. The dimensions of the segment cross-section are the same as for the target footbridge; however, span...
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The impact of natural fibers’ characteristics on mechanical properties of the cement composites
PublikacjaThe paper reviews the properties of cement composites reinforced with short fibres. The effect of natural fibres was investigated: cotton, sisal, jute, ramie, bamboo, and synthetic fibres: polymer and polypropylene. It was noticed that the fibres change the consistency of the mixture up to 15%. In the composite flexural strength tests, a change in strength by +/− 8% was observed, depending on the type of fibres used. The research...
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JamesBot - an intelligent agent playing StarCraft II
PublikacjaThe most popular method for optimizing a certain strategy based on a reward is Reinforcement Learning (RL). Lately, a big challenge for this technique are computer games such as StarCraft II which is a real-time strategy game, created by Blizzard. The main idea of this game is to fight between agents and control objects on the battlefield in order to defeat the enemy. This work concerns creating an autonomous bot using reinforced...
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Basic sensitivity analysis of a telecommunication tower complementing standard reinforcement design process
PublikacjaThis paper presents straightforward sensitivity assessment of a telecommunication tower. The analysis is set toidentify the elements of the tower which may be reinforced with the greatest structural advantage. As current expertopin ions on structural redesign of similar structures due to a planned addition of extra loads are mainly based ondeterministic computations or engineering intuition,...
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Video Classification Technology in a Knowledge-Vision-Integration Platform for Personal Protective Equipment Detection: An Evaluation
PublikacjaThis work is part of an effort for the development of a Knowledge-Vision Integration Platform for Hazard Control (KVIP-HC) in industrial workplaces, adaptable to a wide range of industrial environments. This paper focuses on hazards resulted from the non-use of personal protective equipment (PPE), and examines a few supervised learning techniques to compose the proposed system for the purpose of recognition of three protective...
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Local buckling of composite channel columns
PublikacjaThe investigation concerns local buckling of compressed flanges of axially compressed composite channel columns. Cooperation of the member flange and web is taken into account here. The buckling mode of the member flange is defined by rotation angle a flange about the line of its connection with the web. The channel column under investigation is made of unidirectional fibre-reinforced laminate. Two approaches to member orthotropic...
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LNG TANK IN ŚWINOUJŚCIE: NONLINEAR ANALYSIS OF THE TANK DOME ELEMENTS BEHAVIOUR
PublikacjaIn this paper, the dome of a tank in the Świnoujście LNG terminal is analysed. Some of the rafter ribs at the connection with hangers were not mounted during construction of the tank dome. Therefore, it has become necessary to estimate its response, which has been done with the aid of some computational models of the dome, that have been created in the finite element method environment. Different local models are studied, aiming...
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Study on population dynamics for triple-linked food chain using a simulation-based approach
PublikacjaThe procedures based on simulation have become a feasible testing method that does not require investing valuable resources to create a concrete prototype, especially with the increasing computational power of computers. Thus, design changes can be adopted and design errors can be fixed before it is too late. Simulation turns to be a cheap, safe and often more acceptable from an ethical perspective. In our work we summarize the...
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UWB Microstrip Antennas on a Cylindrical Surfaces
PublikacjaConformal antennas are becoming popular due to their many advantages and possibilities of applications they offer. The advantages of using antennas with a curved surface arise not only from the possibility of integrating them with the object on which they are mounted on but also from the increase, relatively to planar antennas, of their visible angular range. The circular antenna arrays, or arrays of radiators located on the surface...
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Study on Microstructure and Mechanical Properties of Laser Welded Dissimilar Joint of P91 Steel and INCOLOY 800HT Nickel Alloy
PublikacjaThis investigation attempts to explore the weld characteristics of a laser welded dissimilar joint of ferritic/martensitic 9Cr-1Mo-V-Nb (P91) steel and Incoloy 800HT austenitic nickel alloy. This dissimilar joint is essential in power generating nuclear and thermal plants operating at 600–650 °C. In such critical operating conditions, it is essential for a dissimilar joint to preserve its characteristics and be free from any kind...
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The potential of raw sewage sludge in construction industry – A review
PublikacjaExcess sewage sludge produced in any municipal or industrial wastewater treatment plant becomes a serious problem due to its increasing amount. This increase is related to the improvement of treatment technologies, expansion of sewage systems and the development of new industrial plants. The implementation and development of new technologies related to the utilization of sewage sludge is currently based on treating it as a substrate....
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Modele numeryczne uwzględniające tarczową pracę pokrycia dachowego z blach trapezowych
PublikacjaW artykule porównano wybrane sposoby uwzględniania w modelowaniu numerycznym tarczowej pracy pokrycia dachowego z blachy trapezowej, możliwe do zrealizowania w programie Autodesk Robot Structural Analysis Professional 2015, w celu oceny słuszności stosowania ich do obliczeń konstrukcji nośnej współpracującej z poszyciem z blachy trapezowej. Analizy przeprowadzono dla pojedynczej przepony. Za pomocą powłokowych elementów skończonych...
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Ocena odporności na pękanie podbudów drogowych z mieszanek mineralno-cementowo-emulsyjnych (MCE)
PublikacjaPodbudowy z mieszanek mineralno-cementowo-emulsyjnych (MCE) są jednym z wielu materiałów stosowanych do wykonywania warstw nawierzchni w ramach przebudów dróg w Polsce. Mieszanki MCE pozwalają na maksymalne powtórne wykorzystanie istniejących warstw konstrukcyjnych do budowy lub przebudowy nawierzchni. Do wykonania podbudów z MCE stosuje się materiał pochodzący z rozbiórki istniejących warstw (destrukt) bitumicznych, warstw związanych...
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Evaluating the influence of radiative heat flux on convective heat transfer from a vertical plate in air using an improved heating plate
PublikacjaThis article examines the influence of radiative heat flux on the accuracy of the results of free convective heat transfer in air. In order to carry out these tests, based on the experience gained during the operation of a plate heated on one side, compensated by a reverse heat loss flux counter-heater, a unique double-sided heating sandwich plate was designed and built, consisting of three thin epoxy resin plates reinforced with...
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Airborne Laser Scanning Point Cloud Update by Used of the Terrestrial Laser Scanning and the Low-Level Aerial Photogrammetry
PublikacjaLaser scanning technology is a spatial information gathering technique which is commonly used all over the world. Systems where the red-light beam are used, are divided into: terrestrial, mobile and airborne scanning systems. The main differences between those are the accuracy, the data acquisition solution (f. e. in ALS and MLS besides of the laser scanner, the inertial navigation system is required) and the covered area in one...
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Detection of Objects Buried in the Sea Bottom with the Use of Parametric Echosounder
PublikacjaThe paper contains results of a in situ research main task of which was to detect objects buried, partially or completely, in the sea bottom. Object detecting technologies employing acoustic wave sources based on nonlinear interaction of elastic waves require application of parametric sound sources. Detection of objects buried in the sea bottom with the use of classic hydroacoustic devices such as the sidescan sonar or multibeam...
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The point estimate method in a reticulated shell reliability analysis
PublikacjaThe 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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Surprising Radiolytic Stability of 8‑Thiomethyladenine in an Aqueous Solution
Publikacja8-Thiomethyladenine (ASCH3), a potentially radiosensitizing modified nucleobase, has been synthesized in a reaction between 8-thioadenine and methyl iodide. Despite favorable dissociative electron attachment (DEA) characteristics, the radiolysis of an aqueous solution of ASCH3 with a dose of X-ray amounting to as much as 300 Gy leads to no effects. Nevertheless, crossed electron-molecule beam experiments in the gas phase on ASCH3...
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System for characterisation and multidimensional imaging of seafloor using multibeam sonar data
PublikacjaMultibeam sonars are widely used in applications like high resolution bathymetry measurements, underwater object detection and imaging, etc. Also, they are the promising tool in seafloor characterisation and classification, having several advantages over conventional single beam echosounders. The proposed approach to seafloor classification relies on the combined use of three different techniques. In each of them, a set of descriptors...
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Triangular 3D Laser Scanning in Underwater Photogrammetry
PublikacjaThe use of triangular 3D laser scanning may significantly enhance the visual inspection of underwater objects. In these days of high demand for accurate information, exclusively photographic documentation is not enough, as it is geometrically flawed. The authors of this article are trying to present the rudiments of laser scanning, a modern means of measuring, which is reliable, relatively easy to use and works in accordance with...
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Rapid design closure of linear microstrip antenna array apertures using response features
PublikacjaA simple yet reliable approach to a rapid design closure of linear antenna array apertures at the electromagnetic (EM)-simulation level is proposed. Our methodology exploits an underlying array factor (AF) model suitably corrected by means of characteristic points (angles and levels) of the radiation pattern of the EM model of the antenna array aperture. This conveniently allows for controlling both the side lobe levels...
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Influence of fasteners and connections flexibility on deflections of steel building including the stressed skin effect
PublikacjaThe paper presents the analysis of the influence of fasteners and connections flexibility on displacements of symmetrical single-bay pitched-roof steel building, including trapezoidal cladding acting as a diaphragm. The purpose of the article was to compare numerical models with and without taking into consideration fasteners and connections flexibility in order to observe the differences in transverse stiffness of the building...
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ELECTRON ATTACHMENT TO HETEROGENEOUS MOLECULAR CLUSTERS
PublikacjaHeterogeneous clusters are unique model species enabling studies of bulk and surface processes by vacuum restricted methods. This is of particular importance for the reactions of low-energy electrons which have extremely short penetration depth in bulk environments. This contribution overviews our recent experiments with low-energy electrons and clusters prepared by different techniques. First, the deposition of molecules on argon...
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The use of liquid crystal thermography TLC and particle image velocimetry PIV in selected technical applications
PublikacjaNowadays, the energy cost is very high and this problem is carried out to seek techniques for improvement of the aerothermal and thermal (heat flow) systems performances in different technical applications. The transient and steady-state techniques with liquid crystals for the surface temperature and heat transfer coefficient or Nusselt number distribution measurements have been developed. The flow pattern produced by transverse...
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Influence of sheet/purlin fasteners spacing on shear flexibility of the diaphragm
PublikacjaThe paper presents the influence of sheet/purlin fasteners location (in reference to trapezoidal profile cross section) on shear flexibility of the cladding acting as a diaphragm. Analytical procedures were presented and their limitations were discussed. Next, selected schemes of fasteners location, known from engineering practice, but not included in European codes and recommendations, were analysed numerically in order to observe...
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Comparative analysis of different numerical models of a steel radial gate
PublikacjaHydrotechnical structures are important components in water management system and general flooding safety. Their reliability should be ensured since potential damage might lead to catastrophic consequences. Weir gates are considered to be highly vulnerable elements of each hydro power plant, with regard to its dynamic resistance. The aim of the paper is to compare different numerical models and their influence on the results of...
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Numerical modelling of 3D printout using line (1D) elements
PublikacjaA proposition of some numerical modelling of the 3D printout is presented in the paper. The proposed model is composed of some 1D elements. The resulting numerical model of the infill consist of beam, spring and rigid elements. Obtained results confirm correctness of the proposed modelling method. Two methods of estimation of the spring parameters are proposed in the paper. In the first method, mechanical properties of the connecting...
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Dissociative multi-photon ionization of isolated uracil and uracil-adenine complexes
PublikacjaRecent multi-photon ionization (MPI) experiments on uracil revealed a fragment ion at m/z 84 that was proposed as a potential marker for ring opening in the electronically excited neutral molecule. The present MPI measurements on deuterated uracil identify the fragment as C3H4N2O+ (uracil+ less CO), a plausible dissociative ionization product from the theoretically predicted open-ring isomer. Equivalent measurements on thymine...
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Utilization of Gaseous Carbon Dioxide and Industrial Ca-rich Waste for Calcium Carbonate Precipitation: A Review
PublikacjaTechnologies for the management of various types of waste and the production of useful products from them are currently widely studied. Both carbon dioxide and calcium-rich waste from various production processes are problematic wastes that can be used to produce calcium carbonate. Therefore, the purpose of this paper is to provide an overview about the state of the development of processes that use these two wastes...
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Polymeric Bearings as a new base isolation system suitable for mitigating machine-induced vibrations
PublikacjaThe present paper summarizes the preliminary results of the experimental shaking table investigation conducted in order to verify the effectiveness of a new base isolation system consisting of Polymeric Bearings in reducing strong horizontal machine-induced vibrations. Polymeric Bearing considered in the present study is a prototype base isolation system, which was constructed with the use of a specially prepared flexible polymer...
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DESIGN AND CONSTRUCTION OF TILTED WALLS IN ACCORDANCE WITH CODES' PROVISIONS ON THE EXAMPLE OF THE CONSTRUCTION OF THE MUSEUM OF THE SECOND WORLD WAR IN GDAŃSK
PublikacjaThe purpose of this article was to introduce the design and construction of tiled walls in accordance to codes' restrictions. The construction of the Museum of the Second World War in Gdańsk was chosen to be an example of its successful use in practice. Theoretical knowledge was based on PN-EN 1992-1-1:2008 and fib Model Code for Concrete Structures 2010. Although codes' recommendations seem curt, practice prove structural advance....
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Właściwości niskotemperaturowe betonów asfaltowych o wysokim module sztywności (AC-WMS) w badaniach trzypunktowego zginania
PublikacjaArtykuł przedstawia właściwości niskotemperaturowe betonów asfaltowych o wysokim module sztywności. Przedstawione wyniki zostały uzyskane w dwóch badaniach zginania trzypunktowego próbek belkowych: ze stałą prędkością przemieszczenia oraz pod stałym obciążeniem. Obie te metody są od dawna stosowane na Politechnice Gdańskiej do oceny właściwości niskotemperaturowych betonów asfaltowych. Badaniu poddano pięć betonów asfaltowych –...
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Application of Shape Memory Alloys in Retrofitting of Masonry and Heritage Structures Based on Their Vulnerability Revealed in the Bam 2003 Earthquake
PublikacjaFor decades, one of the most critical considerations of civil engineers has been the construction of structures that can sufficiently resist earthquakes. However, in many parts of the globe, ancient and contemporary buildings were constructed without regard for engineering; thus, there is a rising necessity to adapt existing structures to avoid accidents and preserve historical artefacts. There are various techniques for retrofitting...
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Dielectric properties of modified graphene oxide filled polyurethane nanocomposites and its correlation with rheology
PublikacjaThis study aims at investigating the dynamic mechanical, dielectric and rheological properties of reinforced polyurethane (PU) nanocomposites containing hydrophilic graphene oxide (GO) and/or hydrophobic modified graphene oxide (mGO) sheets. The organic modification of GO was performed with 4,4′-methylenebis (phenyl isocyanate) (MDI) and the samples were prepared by solvent mixing. We found that addition of mGO provides a more...
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Material characterisation of biaxial glass-fibre non-crimp fabrics as a function of ply orientation, stitch pattern, stitch length and stitch tension
PublikacjaDue to their high density-specific stiffnesses and strength, fibre reinforced plastic (FRP) composites are particularly interesting for mobility and transport applications. Warp-knitted non-crimp fabrics (NCF) are one possible way to produce such FRP composites. They are advantageous because of their low production costs and the ability to tailor the properties of the textile to the reinforcement and drape requirements of the application....
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Multiparameter sensitivity analysis of a GFRP composite footbridge of a sandwich structure and U-shaped cross-section
PublikacjaThe paper deals with multiparameter sensitivity analysis of a composite footbridge. A shell‐like structure is 14.5 m long shows U‐shaped cross‐section and inner service dimensions 1.3 × 2.5 m. Glass fiber reinforced polymer GFRP laminate constitutes faces of a sandwich structure while PET foam received from recycled bottle builts a core. The structure was divided into 285 independent areas where the thickness of laminates and stiffness...