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Non-Destructive Assessment of Masonry Pillars using Ultrasonic Tomography
PublikacjaIn this paper, a condition assessment of masonry pillars is presented. Non-destructive tests were performed on an intact pillar as well as three pillars with internal inclusions in the form of a hole, a steel bar grouted by gypsum mortar, and a steel bar grouted by cement mortar. The inspection utilized ultrasonic stress waves and the reconstruction of the velocity distribution was performed by means of computed tomography. The...
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Contribution to the capacity analysis of the classic composite girder of Möller
PublikacjaThe analysis (brief history, experiments, numerical method) of the classic composite girder of Moller has been presented.
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Sensitivity analysis of critical forces of trusses with side bracing
PublikacjaThe present research is devoted to the study of out-of-plane buckling of trusses with elastic side bracing. Inthis paper, a sensitivity analysis of critical buckling loads of a truss due to bracing stiffness is carried out. A method based on the sensitivity analysis for the determination of the threshold bracing stiffness conditionfor full bracing of a truss is proposed. The influence lines of the unit change of the bracing stiffness...
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The aluminium and polycarbonate covering to the roof over the stadium in Gdańsk
PublikacjaThis paper presents information about structural elements of the roof covering to the stadium in Gdansk built for the 2012 European Football Championship in Poland and the Ukraine. The paper discusses elements of the polycarbonate covering, the supporting structure and the drainage system. It also provides information about tests and research performed prior to construction, which determined the solutions adopted as well as...
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Truss imperfections in the design of bar and diaphragm bracing systems
PublikacjaIn the article three variants of roof bracing were considered: bar bracing, diaphragm bracing and the combination of bar and diaphragm bracing. Different analytical and numerical ways of taking into account the imperfections of the truss girder were compared. The entire 3D model of the roof (shell and beam elements with the eccentricities taken into account) was analysed numerically. Selected stressed-skin aspects were considered....
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Simplified numerical model for global stability of corrugated silos with vertical stiffeners
PublikacjaArtykuł omawia wyniki stateczności globalnej silosów z blachy falistej z pionowymi usztywnieniami. Zaproponowano uproszczony model numeryczny metody elementów skończonych do określenia stateczności. Wyniki numeryczne były bardziej dokładnie niż metody zaproponowane w Eurokodzie.
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Advantages of the Application of the Temper Bead Welding Technique During Wet Welding
PublikacjaThermo-mechanically rolled S460ML steel was chosen for welding in underwater wet welding conditions by covered electrodes. The main aim of this study was to check the weldability for fillet welds in a water environment by controlled thermal severity (CTS) tests and to check the influence of temper bead welding (TBW) on the weldability of the investigated steel. Non-destructive and destructive tests showed that S460ML steel has...
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Effective method for determining environmental loads on supporting structures for offshore wind turbines
PublikacjaThis paper presents a description of an effective method for determining loads due to waves, current and wind acting on the supporting structures of the offshore wind turbines. This method is dedicated to the structures consisting of the cylindrical or conical elements as well as (truncates) pyramids of polygon with a large number of sides (8 or more). The presented computational method is based on the Morison equation, which was...
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Effective method for determining environmental loads on supporting structures for offshore wind turbines
PublikacjaThis paper presents a description of an effective method for determining loads due to waves and current acting on the supporting structures of the offshore wind turbines. This method is dedicated to the structures consisting of the cylindrical or conical elements as well as (truncates) pyramids of polygon with a large number of sides (8 or more). The presented computational method is based on the Morison equation, which was originally...
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Chemical, Physical, and Mechanical Properties of 95-Year-Old Concrete Built-In Arch Bridge
PublikacjaThis research aimed to determine the durability and strength of an old concrete built-in arch bridge based on selected mechanical, physical, and chemical properties of the concrete. The bridge was erected in 1925 and is located in Jagodnik (northern Poland). Cylindrical specimens were taken from the side ribs connected to the top plate using a concrete core borehole diamond drill machine. The properties of the old concrete were...
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An application for a new type of pneumatic engine concept
PublikacjaHeavy trucks are often equipped with loading and unloading systems like dock levellers with swing lip or telescopic lip. Most of these devices require hydro-electrical energy supply systems (eg. the pump that presses the working substance to the actuators must be propelled by electric engine.) The space taken by pump with electric engine can be reduced on condition that a new type of pneumatic drive will be considered. It is possible...
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DETERMINATION OF SEAKEEPING PERFORMANCE FOR A CASE STUDY VESSEL BY THE STRIP THEORY METHOD
PublikacjaThe increase of seakeeping performance is of particular importance for car and passenger ferries, service ships in the gas and oil extraction industry and offshore wind power farm industry, as well as for special purpose ships (including military applications). In the water areas of the Baltic Sea, North Sea, and Mediterranean Sea, which are characterised by a short and steep wave, the hull shape has a substantial impact on the...
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Numerical analysis of high temperature minichannels heat exchanger performance
PublikacjaNowadays, the most difficult technological challenge in energy sector is connected with the gas micro-CHP units, dedicated to the distributed power generation. They are expected to be of high efficiency and at the same time of compact in size. Regarding the first reason, significant increase in microturbine efficiency can only be achieved by increase in the engine operating temperature. Therefore, one of the critical elements in...
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The influence of core material on strength properties of hybrid sandwich panels
PublikacjaAlong with high prices of fuels and more restrictive safety and environmental regulations (including environment protection) increased interest in sandwich structures is being observed. One of the solution having growing application potential is steel sandwich panel. The construction consist of very thin steel plates (about 2mm) and stiffeners between them. The main advantage of using such solution is very high strength to weight...
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Experimental Testing of Innovative Cold-Formed "GEB" Section / Badania Eksperymentalne Innowacyjnego Kształtownika Giętego Na Zimno Typu „Geb“
PublikacjaOne of the major advantages of light gauge steel structures made of cold-formed steel sections is their low weight, so manufacturers are increasingly using the possibilities of those sections for the production of typical single-storey steel structures systems. Well known profiles, such as Z, C and the so called hat sections that have been studied and described in the literature, are used mainly as purlins or truss components....
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Laminated plates and shells - first ply failure analysis within 6-parameter shell theory
PublikacjaThis work describes Tsai-Wu and Hashin criteria modifications, dictated by nonlinear 6-parameter shell theory with asymmetric strain measures and drilling rotation. The material law is based on standard orthotropic elastic constants for a non-polar continuum, under plane state of stress. First ply failure loads of cylindrical panel subjected to pressure and flat compressed plate are estimated by means of Finite Element Analysis....
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Study of prototype multi-pole non-salient field winding for high speed brushless synchronous generator
PublikacjaIn this paper a non-salient field winding for a brushless synchronous generator working with high speed in an autonomous energy generation system (e.g. airplane power grid) has been presented. A conception of a six-pole cylindrical-rotor with distributed field winding has been proposed. Comparison study of salient and prototype non-salient field winding has been carried out. Chosen simulation and measurement results of the generator...
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Dynamics of Field Line Mappings in Magnetic Flux Tubes
PublikacjaWe study the topological constraints on the dynamics of magnetic field lines in flux tubes. Our approach is based on the application of the topological invariant: fixed point index. We consider periodic flux tubes and find various restrictions on the field lines that come from the sequence of fixed point indices of iterations. We also analyze the case of a tube with a cylindrical obstacle, deducing some special dynamical properties...
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Analysis of features of stainless steels in dissimilar welded joints in chloride inducted corrosion
PublikacjaStainless steels of femtic-austenitic microstructure that means the duplex Cr-Ni-Mo steels, in comparison with austenitic steel includes less expensive nickel and has much better mechanical properties with good formability and corrosion resistance, even in environments containing chloride ions. Similar share of high chromium ferrite and austenite, which is characterized by high ductility, determines that the duplex steels have...
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Experimental study on the feasibility of alternative materials for tilting pad thrust bearings operating in transition to mixed friction
PublikacjaIn hydrodynamic bearings traditional bearing alloys: Babbitts and bronzes are most frequently utilized. Polymer sliding layers are sometimes applied as a valuable alternative. Hard diamond-like carbon (DLC) coatings, which are also considered for certain applications may show some advantages, as well. Although material selection is of secondary importance in a full film lubrication regime it becomes important in mixed friction...
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Quasi-resonant DC-link voltage inverter with enhanced zero-voltage switching control
PublikacjaA new topology modification of the parallel quasi-resonant circuit for a dc-link voltage inverter enables regulation of the zero voltage dc-link subperiods and the dc-link voltage gradient settings. The proposed circuit is based on four MOSFET switches with free-wheeling diodes for controlled quasi-resonant recharging between L-C tank in order to assure inverter zero voltage switching (ZVS) conditions. Design optimization of the...
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IMPACT-TOUGHNESS INVESTIGATIONS OF DUPLEX STAINLESS STEELS
PublikacjaDuplex stainless steels are very attractive constructional materials for use in aggressive environments because of their several advantages over austenitic stainless steels. Duplex steels have excellent pitting and crevice corrosion resistance, are highly resistant to chloride stress-corrosion cracking and are about twice as strong as common austenitic steels. Better properties are associated with their microstructures consisting...
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ENVIRONMENTAL DEGRADATION OF DISSIMILAR AUSTENITIC 316L AND DUPLEX 2205 STAINLESS STEELS WELDED JOINTS
PublikacjaThe paper describes structure and properties of dissimilar stainless steels welded joints between duplex 2205 and austenitic 316L steels. Investigations were focused on environmentally assisted cracking of welded joints. The susceptibility to stress corrosion cracking (SCC) and hydrogen embrittlement was determined in slow strain rate tests (SSRT) with the strain rate of 2.2 × 10–6 s–1. Chloride-inducted SCC was determined in the...
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Experimental review of the performances of protective coatings for interconnects in solid oxide fuel cells
PublikacjaFerritic stainless steel interconnects are used in solid oxide fuel cells; however, coatings are required to improve their performance. Although several types of coatings have been proposed, they have been scarcely investigated under similar conditions. This study compares the characteristics of uncoated Crofer 22 APU and eight different coatings on Crofer 22 APU for up to 3000 h at 800 ◦C. The coatings were deposited at various...
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A New Approach of Solidification Analysis in Modular Latent Thermal Energy Storage Unit Based on Image Processing
PublikacjaThe solidification process of RT18HC in a cylindrical shell and tube storage unit has been studied using a new methodology based on image processing. The main idea of the algorithm is to label the region of solidification and use statistical functions to calculate the dimensions of the solidification front over time. Said analysis includes two methods. The first method is to measure the solid fraction changes during solidification....
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A review of phase change materials and heat enhancement methodologies
PublikacjaPhase change materials (PCMs) are an efficient alternative to store and release heat at a specific range of temperature. Here PCMs and heat enhancement methodologies for PCM storage are reviewed. A short overview of PCMs and their applications is presented in addition to the progress during the last 10 years. Heat enhancement techniques, that is, extended surfaces, multiple and composite PCMs, and encapsulation techniques, are...
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Zabezpieczenia antykorozyjne stalowych barierek ochronnych na obiektach mostowych w ujęciu kosztów cyklu ich życia
PublikacjaThe article presents the Life Cycle Costs analysis of steel safety barriers operated in road lane conditions, located on a selected bridge structure. Three corrosion protection systems were proposed, analyzing them in terms of the cost of initial and planned outlays related to maintenance. Based on the LCC analysis for three options, taking into account the 25-year lifetime of the barriers, the optimal solutionwas indicated, i.e....
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Analiza wpływu transmisji danych na jakość działania rozproszonych systemów sterowania
PublikacjaW artykule przedstawiono zagadnienia związane z transmisją danych w rozproszonych systemach sterowania. Opisano cechy charakterystyczne przemysłowych sieci i protokołów informatycznych. Utworzono model rozproszonego systemu sterowania poziomem cieczy w zbiorniku, w którym komunikacja oparta została na protokole Modbus RTU. Na podstawie zmian parametrów transmisji danych wykazano, że poprawna komunikacja pomiędzy elementami systemu...
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Effect of Arc Strikes on High Strength Low Alloy Steels Welded by SMAW
PublikacjaWet welding with covered electrodes (Shielded Metal Arc Welding – SMAW) is the most commonly used method of carrying out welding repair works in a water environment. Limited visibility and the inability to move freely under water result in an increased risk of formation of welding imperfections such as lack of fusion, lack of penetration and arc strikes. The work focused on changes in the properties and structure of steel subjected...
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Elastic Fender-Dolphin Interaction for Economic Design of Berthing Dolphins
PublikacjaThe study addresses the question of the possible design benefits when considering the interaction between a modern marine modular rubber fender and a steel tubular pile substructure of a berthing dolphin. Absorption of the berthing kinetic energy of the vessel by a dualelasticity pile-fender berthing system is described in detail using the interactive treatment method (ITM). Application of the ITM is illustrated by a calculative...
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Three dimensional simulations of FRC beams and panels with explicit definition of fibres-concrete interaction
PublikacjaHigh performance concrete (HPC) is a quite novel material which has been rapidly developed in the last few decades. It exhibits superior mechanical properties and durability comparing to normal concrete. HPC can achieve also superior tensile performance if strong fibres (steel or carbon) are implemented in the matrix. Thus, there exist the unabated interest in studying how the addition of different types of fibres modifies the...
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The effect of surfactants mixtures composition on wetting of different solid materials
PublikacjaThe wetting properties of surfactants mixtures were investigated. Three types of compounds were used: nonionic gemini α, α'-[2,4,7,9-tetramethyl-5-decyne-4,7-diyl]bis[ω-hydroxyl-olioxyethylene] (S-10), anionic sodium dodecyl sulphates (SDS) and cationic dodecyl trimethyl ammonium bromide (DTAB). The materials used in wetting experiments were steel and methyl polymethacrylate. These materials differ...
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Development of Microstructured Carbon Coatings by Substrate-Catalytic CVD
PublikacjaCarbon nanostructured films were synthesized by chemical vapor deposition (CVD) on H18 stainless steel (AISI 440C) sheets with an H2/CH4/N2 gas mixture at various substrate temperatures. During the synthesis, the iron and chromium oxide layer was formed between the steel and carbonaceous layer. The carbon films exhibited wall-like and spherical morphologies and structures, as characterized by scanning electron microscopy and Raman...
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Experimental investigations on pressure drop during the condensation in flow of HFE7000 in vertical minichannel
PublikacjaIn the work presented in the paper authors focused attention on the issues of flow resistance and pressure drop during condensation in the flow. The case of the descending flow through a cylindrical single-channel of 2.3 mm inner diameter was carefully analyzed. In the course of investigations a new working fluid HFE 7000 has been scrutinised which has a strongly differing properties in comparison to the other fluids that are commonly...
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Calculation methods of interaction of electromagnetic waves with objects of complex geometries
PublikacjaModeling of the electromagnetic interaction with different homogeneous or inhomo-geneous objects is a fundamental and important problem. It is relatively easy to solve Maxwellequations analytically when the scattering object is spherical or cylindrical, for example. How-ever, when it loses these properties all that is left for us is to useapproximation models, to ac-quire the solution we need. Modeling of complex, non-spherical,...
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Determination of causes of accelerated local corrosion of austenitic steels in water supply systems
PublikacjaThis paper concerns an inspection of a water supply system, made of AISI 304 steel, which showed signs of local corrosion at the weld. Such corrosion caused material perforation after very short periods of operation. It was revealed that steel was sensitised during the welding process. It was also proven that chromium micro-segregation occurred in the alloy leading to galvanic cell formation which initialised the process of pitting...
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Meso‐scale analyses of size effect in brittle materials using DEM
PublikacjaThe paper describes numerical meso-scale results of a size effect on strength, brittleness and fracture in brittle materials like concrete. The discrete element method (DEM) was used to simulate the size effect during quasi-static splitting tension with the experimental-based meso-structure. The two-dimensional (2D) calculations were carried out on concrete cylindrical specimens with two diameters wherein two different failure...
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Fe-modified Mn2CuO4 spinel oxides: coatings based on abundant elements for solid oxide cell interconnects
PublikacjaThe current state of the art steel interconnect coating materials are based on critical raw material - Co-oxide spinels. Replacing Co-oxide spinels with alternative, abundant materials can reduce the dependence on the critical raw materials. Cobalt-free coatings with the general formula Mn2-xCuFexO4, where x = 0, 0.1, 0.3, were electrophoretically deposited on a ferritic stainless-steel support and evaluated. Prior to deposition,...
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Multilayer coatings based on cerium oxide and manganese cobaltite spinel for Crofer22APU SOC interconnects
PublikacjaThe current state of the art steel interconnect coating materials are based on critical raw material - Co-oxide spinels. Replacing Co-oxide spinels with alternative, abundant materials can reduce the dependence on the critical raw materials. Cobalt-free coatings with the general formula Mn2-xCuFexO4, where x = 0, 0.1, 0.3, were electrophoretically deposited on a ferritic stainless-steel support and evaluated. Prior to deposition,...
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Projektowanie zbiornika na nieczystości ciekłe
PublikacjaW artykule przedstawiono proces projektowania zbiornika podziemnego na nieczystości ciekłe o pojemności ok. 10 m3 posadowionego na gruntach niespoistych (sypkich). Porównano wartości sił wewnętrznych w przypadku skrajnie różnych warunków gruntowych: piasku drobnego o ID = 0,2 oraz żwiru o I D = 0,7. Dodatkowo przeanalizowano wpływ modelu obliczeniowego podłoża na wyniki sił wewnętrznych. Opisano procedurę normową pozwalającą na...
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Innovative cold-formed GEB section under compression
PublikacjaCold-formed steel sections extensively affect the modern steel construction industry. Not only are they used as secondary elements like purlins or sheeting, but also they can serve as primary load-bearing members in fabricated steel panels and trusses. A new cross-section called shortly a GEB may serve as that member. However, its existence of the metal building structures industry depends on the exact, optimal dimensional parameters...
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The validation process of truss model with joint eccentricities
PublikacjaNowadays, due to the technological reasons in modern lightweight steel trusses, fabricated from cold-formed sections, positive eccentricities appear in the truss nodes, to induce additional forces truss chords. In order to account for the real load-carrying capacity of truss node area the steel structure research was conducted in scale 1:1. As a result of experimental research, the forms of deformation and strains of the walls...
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Assessment of crack resistance of ship steels according to SEP 1390 standard
PublikacjaThe aim of the study was to evaluate the weldability of E36 nd NVE-36 steels by bending test according to SEP 1390. In the case of the specimen from E36 steel 9 external cracks were found, 5 of which were stopped in the fusion line and 4 in heat affected zone. In the case of the specimen from NVE-36 steel 8 external cracks were found, 4 of which were stopped in the fusion line and 4 in heat affected zone. Results of bending test...
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Impact of cross-section centers estimation on the accuracy of the Point cloud spatial expansion using robust M-estimation and Monte Carlo simulation
PublikacjaThe point cloud spatial expansion (PCSE) method creates an alternative form of representing the shape of symmetrical objects and introduces additional descriptive geometric parameters. An important element of the procedure is determining the course of the axis of symmetry of cylindrical objects based on cross-sections of point clouds. Outliers occurring in laser measurements are of great importance in this case. In this study,...
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3D POINT-CLOUD SPATIAL EXPANSION BY TOTAL LEAST-SQUARES LINE FITTING
PublikacjaPoint-cloud spatial expansion (PCSE) allows the creation of a new pointcloud form that presents an alternative geometry of an entire object in a single spatial view. Spatial expansion facilitates the analysis process and introduces an additional spatial parameter describing the point cloud. An important element of the PCSE method is determining the position of the axis of symmetry of a symmetrical object: the procedure for determining...
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Wyznaczanie wytrzymałości betonu na podstawie funkcji dojrzałości wg amerykańskiej normy ASTM C1074-11
PublikacjaArtykuł poświęcono wyznaczaniu wytrzymałości betonu na podstawie funkcji dojrzałości wg normy ASTM C1074-11 (ang. Maturity Method). Metoda bazuje na rejestracji zmian tem - peratury w trakcie hydratacji dojrzewającego betonu. Wartykule zaprezentowano procedurę badawczą służącą wyznaczeniu funk - cji dojrzałości dla wybranej mieszanki betonowej oraz zależności wytrzymałość-dojrzałość. Celem badań jest wyznaczanie zmian w czasie...
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Wpływ kształtu elektrody woltamperometrycznej na jej właściwości metrologiczne w dziedzinie czasu
PublikacjaW artykule omówiono właściwości metrologiczne elektrod woltamperometrycznych. Wykazano, że w przypadku oznaczania małych wartości stężeń jonów metali, elektrody te zachowują się tak jak przetworniki pomiarowe I rzędu. Ich właściwości metrologiczne opisuje czułość i stała czasowa. Wartości tych wielkości są uzależnione od mechanizmu transportu jonów do/od powierzchni elektrod oraz od ich kształtu. Wykonano symulacje wpływu kształtu...
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Investigations on fracture in reinforced concrete beams in 3-point bending using continuous micro-CT scanning
PublikacjaThis study explores a fracture process in rectangular reinforced concrete (RC) beams subjected to quasi-static three-point bending. RC beams were short and long with included longitudinal reinforcement in the form of a steel or basalt bar. The ratio of the shear span to the effective depth was 1.5 and 0.75. The focus was on the load–deflection diagram and crack formation. Three-dimensional (3D) analyses of the size and distribution...
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Assessment of damage causes of a 17 m long wind turbine blade model
PublikacjaThe subject matter is to verify the stiffness of the steel supporting structure and assess the causes of cracks in the 17 m long wind turbine blade model
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Manoeuvring forces on azimuthing podded propulsor model
PublikacjaThis paper presents the preliminary part of comprehensive manoeuvring open- water tests of a gas carrier model. The paper focuses on open water experiments with an azimuthing podded propulsor. The test program was carried out in the cavitation tunnel and the large towing tank of Ship Hydromechanics Division, Ship Design and Research Centre, Gdańsk. The pod was tested as a pushing unit with a 161.3 mm diameter propeller. Steering...