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Search results for: TORSION
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Impact of high temperature drying process on beech wood containing tension wood
PublicationThe technology of high temperature drying has a great inuence on dimensional and selected physical changes in tension wood. Article is focused on the measurement properties such as moisture content, color changes and longitudinal warping. The quality of beech wood is determined based on structure and properties of wood, frequency of defects in wood material. The tension wood is considered as an important wood defect causing negative...
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An Influence of Factors of Flow Condition, Particle and Material Properties on Slurry Erosion Resistance
PublicationThe degradation of materials due to slurry erosion is the serious problem which occurs in the power industries. The paper presents actual knowledge about an influence of individual factors connected with flow conditions, particles and material properties on the slurry erosion resistance. Among the factors connected with operating conditions, an influence of impact angle, and velocity of impact, particle concertation and liquid...
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Optical flow method for measuring deformation of soil specimen subjected to torsional shearing
PublicationIn this study optical flow method was used for soil small deformation measurement in laboratory tests. The main objective was to observe how the deformation distributes along the whole height of cylindrical soil specimen subjected to torsional shearing (TS test). The experiments were conducted on dry non-cohesive soil specimens under two values of isotropic pressure. Specimens were loaded with low-amplitude cyclic torque to analyze...
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Effect of Thermal Treatment and Erosion Aggressiveness on Resistance of S235JR Steel to Cavitation and Slurry
PublicationS235JR steel is used in many applications, but its resistance to the erosion processes has been poorly studied. To investigate this resistance, cavitation, and slurry erosion tests were conducted. These tests were carried out at different erosion intensities, i.e., different flow rates in the cavitation tunnel with a system of barricades and different rotational speeds in the slurry pot. The steel was tested as-received and after...
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Effect of a characteristic length on crack spacing in a reinforced concrete bar under tension.
PublicationW artykule przedstawiono wyniki numerycznej obliczenia rozstawu rys w pręcie żelbetowym poddanemu rozciąganiu. Obliczenia wykonano przy zastosowaniu sprężysto-plastycznego modelu rozszerzonego o długość charakterystyczna mikrostruktury przy pomocy teorii nielokalnej.
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The Influence of Impact Velocity on Stresses and Failure of S355j2 Steel Under Slurry Erosion Conditions
PublicationThe purpose of this work was to determine the essence of the influence of the impact velocity (5, 7, and 9 m/s) on Hertzian stresses and the erosion mechanism of ferritic-pearlitic S355J2 steel. The investigations were carried out using a slurry pot tester. S355J2 steel showed a strong sensitivity to changes in impact velocity. A significant increase in erosion rate was observed at a velocity of 9 m/s. This increase was 5-fold...
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Overflowing tests at the Polish DredgDikes research dike – stability of the dike surface against erosion
PublicationIn the project DredgDikes the different research dike embankments were tested with respect to overflowing water induced erosion. Therefore, flumes were installed on the land side embankments in which the effect of overflowing water on the vegetated surface was investigated. On the Polish DredgDikes research dike near Gdansk, Poland, two parallel flumes were installed and the surface of the dike made of different mixtures of...
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Torsional earthquake-induced pounding between adjacent buildings founded on different soil types
PublicationThis paper investigates the effect of the soil type on the torsional response of build- ings experiencing torsional pounding due to earthquake excitations. Six buildings (one 4-storey building and five 6-storey buildings) with different configurations have been considered. First, pounding between different structures has been analysed for a specified soil type and the effect of the torsional pounding and the contact asymmetry on...
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The effect of nonlinear restraint on torsional buckling and post-buckling behaviour of a thin-walled column
PublicationW pracy rozważa się wyboczenie skrętne i zachowanie pokrytyczne osiowo ściskanego swobodnie podpartego pręta cienkosciennego o przekroju otwartym ze sprężytą nieliniową podporą w środku rozpietości. Rozwiązanie problemu wyznaczono za pomocą metody małego parametru. W przykładzie numerycznym wyznaczono siłę krytyczną i ścieżkę początkowego zachowania pokrytycznego dwuteowego pręta z podporą sprężystą o charakterystyce składającej...
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The Influence of Impact Velocity on Stresses and Failure of S355j2 Steel Under Slurry Erosion Conditions
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Range of motion of resistance exercise affects the number of performed repetitions but not a time under tension
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A novel version of simulated annealing based on linguistic patterns for solving facility layout problems
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The new version of contact-less method for localisation of catenary contact wire – theoretical assumption
PublicationThis article presents the theoretical basic of a new version of contact-less method for localising the catenary contact wires, using the advanced video techniques and image analysis. So far, contact line diagnostic systems exploited nowadays uses the contact measuring methods with special design current collector. This solutions make it impossible to measure the contact line geometry in a static way. The proposed measurement method...
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The effect of boiling in a thermosyphon on surface tension and contact angle of silica and graphene oxide nanofluids
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Concept of cavitation erosion assessment of austenitic 1.4301 stainless steel based on roughness development
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Cavitation Erosion Resistance of Austenitic Stainless Steel after Glow-Discharge Nitriding Process
PublicationThis paper presents investigation of cavitation erosion resistance of nitrided austenitic stainless steel X5CrNi18-10. The diffusion layers were produced by using different parameters of atmosphere (N2:H2). The microstructure, chemical composition and phase identification of the modified layer were examined using scanning electron microscopy, glow-discharge optical emission spectrometer and X-ray diffractometry, respectively. Cavitation...
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DETERMINATION OF ADDITIONAL TENSION IN TOWED STREAMER CABLE TRIGGERED BY COLLISION WITH UNDERWATER MOVING OBJECT
PublicationThe paper deals with issues connected with the behaviour of a streamer cable towed by a survey seismic vessel when the cable undergoes a strike triggered by collision with an underwater moving object. The consequences of such collisions may be both threat to the life of marine animals or damage to underwater units and large economic losses suffered by vessel owners. The risk of such collisions has increased over the last years...
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Numerical modelling of the mesofracture process of sintered 316L steel under tension using microtomography
PublicationThis paper concerns numerical modelling of the deformation process, taking into account the local fracture of porous 316L sinters at the mesoscopic scale using the finite element method. Calculations are performed with the use of geometrical models, to map the realistic shape of the porous mesostructure of the material, obtained by means of computed microtomography. The microtomographic device has limited and insufficient measurement...
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Effect of MAO coatings on cavitation erosion and tribological properties of 5056 and 7075 aluminum alloys
PublicationTwo ceramic coatings have been applied on 5056 and 7075 aluminum alloy by microarc oxidation (MAO) technology. The mass losses, surface morphologies and the phase constituents of the MAO coatings before and after cavitation tests were examined by means of digital scales, scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. In order to assess the impact of the mechanical properties of the surface layer on...
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Cavitation erosion behavior of 18/8 stainless steel after its laser alloying of manganese
PublicationW pracy przedstawiono badania kawitacyjne stali austenitycznej 18/8 po laserowym stopowaniu jej powierzchni różną zawartością manganu. Oceniano podatnoś stopowanej powierzchni do odkształceniowego umacniania pod wpływem obciążeń kawitacyjnych oraz głębokość umocnienia.
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Corrosion-erosion damage of heat exchanger tubes by desalted crude oil flowing at shell side.
PublicationRurki wymiennika zostały uszkodzone lokalnie przez odsoloną ropę naftową przepływającą pod ciśnieniem 2,6 MPa i w temperaturze 385-395K. Większość powierzchni rurek nie była uszkodzona i była pokryta osadem związków organicznych i nieorganicznych, zabezpieczającym przed uszkodzeniami. Badania wykluczyły możliwość występowania intensywnej korozji elektrochemicznej na powierzchniach rurek pozbawionych osadu. Przyczyną perforacji...
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Cavitation erosion behavior of 18/8 stainless steel after its laser alloying of manganese
PublicationW pracy przedstawiono wyniki badań własności kawitacyjnych stali nierdzewnej gatunku 18/8 po jej laserowym stopowaniu różną zawartością manganu. Stwierdzono, że przy zawartości Mn w ilości 7,13% występuje największy wzrost twardości po stopowaniu a głębokość umacniania na skutek działania obciążeń kawitacyjnych jest najmniejsza.
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Corrosion-erosion damage of heat exchanger tubes by desalted crude oil flowing at shell side
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Original article Polish version of the Cognitive Distortions Scale (CDS): Preliminary validation and personality correlates
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The use of terrestrial laser scanning in monitoring and analyses of erosion phenomena in natural and anthropogenically transformed areas
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Polish version of the White Bear Suppression Inventory (WBSI) by Wegner and Zanakos: factor analysis and reliability
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Modeling by finite element methods of impact of erosion on frequency of normal modes of L-0 blade
PublicationAfter some time of exploitation steam turbine rotors blades in energetic industry they are being eroded and also their frequency of normal modes is changed. Those changes can cause to unwanted shift of blades normal mode frequencies. It is necessary to find quick method of rating changes of frequency in connection of mass loss due erosion. The evaluation of this dependence was made by finite element modeling method using HyperWorks...
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The impact of drying and steaming processes on surface color changes of tension ad normal beech wood
PublicationThe aim of the article is to present the influence of high temperature to selected properties of beech wood (Fagus sylvatica L.). The properties such as moisture content, color changes and longitudinal warping were analyzed. The quality of beech wood is determined based on structure and properties of wood, frequency of defects in wood material. The tension wood is considered as an important wood defect causing negative alterations...
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EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF CONCRETE BEHAVIOUR AT MESO-LEVEL DURING QUASI-STATIC SPLITTING TENSION
PublicationThe paper describes experimental and numerical results of quasi-static splitting tensile tests on concrete specimens at meso-scale level. The loading strip was made of plywood or steel. Fracture in concrete was detected at the aggregate level by means of three non-destructive methods: 3D x-ray micro-computed tomography, 2D scanning electron microscope and manual 2D digital microscope. The discrete element method was used to directly...
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Experimental and numerical investigations of concrete behaviour at meso-level during quasi-static splitting tension.
PublicationArtykuł omawia wyniki numeryczne dotyczące pękania betonu uzyskane stosując metodę elementów dyskretnych. Dwuwymiarowe obliczenia wykonano dla próbek betonowych podczas rozłupywania. Beton został opisany jako model 4-fazowy. Mikrostruktura betonu odpowiadała zdjęciom tomograficznym. Zbadano wpływ warunków brzegowych na proces pękania. W obliczeniach zwrócono uwagę na porzebieg zjawisk mikrostrukturalnych przebieg pękania. Wyniki...
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Textile reinforced concrete members subjected to tension, bending, and in-plane loads: Experimental study and numerical analyses
PublicationTextile reinforced concrete has raised increasing research interest during the last years, mainly due to its potential to be used for freeform shell structures involving complex load situations. Yet, most experimental work has focused on test setups with primarily uniaxial loading. In the current work, such setups are complemented with a novel test setup of deep beams, including in-plane bending and shear. Further, nonlinear finite...
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Evaluation of cavitation erosion–corrosion degradation of mild steel by means of dynamic impedance spectroscopy in galvanostatic mode
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Discrete-Element bonded-particle Sea Ice model DESIgn, version 1.3a – model description and implementation
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Discrete-Element bonded particle Sea Ice model DESIgn, version 1.3 – model description and implementation
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The acute effects of caffeine intake on time under tension and power generated during the bench press movement
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Whole genome sequencing of Fowl aviadenovirus A - a causative agent of gizzard erosion and ulceration, in adult laying hens
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Rivers Try Harder. Reversed “Differential Erosion” as Geological Control of Flood in the Large Fluvial Systems in Poland
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Multidimensional attitudes scale toward persons with disabilities: factor and exploratory analysis for a Ukrainian version (MAS-UA)
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ANALYSIS OF UNCONTROLLED WEAR IN THE AREA OFA BELLEVILLE SPRING OF A FRICTION TORSIONAL VIBRATIONDAMPER IN A MOTOR VEHICLE CLUTCH
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PAID-PL—The Polish Version of the Problem Areas in Diabetes Scale: Perfect Reliability and a One-Factor Structure
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Impact of movement tempo on bar velocity and time under tension in resistance exercises with different external loads
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Design of Structure of Tension Leg Platform for 6 MW Offshore Wind Turbine Based On Fem Analysis
PublicationThe article presents the calculation and design stages of the TLP platform serving as a supporting construction of a 6 MW offshore wind turbine. This platform is designed to anchor at sea at a depth of 60 m. The authors presented the method of parameterization and optimization of the hull geometry. For the two selected geometry variants, the load and motion calculations of the platform subjected to wind, wave and current under...
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Evaluation of cavitation erosion-corrosion degradation of mild steel by means of Dynamic Impedance Spectroscopy in galvanostatic mode
PublicationPrzedstawiono wyniki badań degradacji stali węglowych na skutek oddziaływania erozji-korozji kawitacyjnej. Do analizy wykorzystano technikę Dynamicznej Elektrochemicznej Spektroskopii Impedancyjnej w trybie galwanostatycznym, bliżej odwzrorowującym warunki naturalne. Do oceny stopnia degradacji posłużyły również funkcja ubytku masy MDPR oraz obrazy mikroskopowe SEM. Potwierdzono wpływ łączonej degradacji erozyjno-korozyjnej na...
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Sensitivity analysis of free torsional vibration frequencies of thin-walled laminated beams under axial load
PublicationThe paper addresses sensitivity analysis of free torsional vibration frequencies of thin-walled beams of bisymmetric open cross-section made of unidirectional fibre-reinforced laminate. The warping effect and the axial end load are taken into account. The consideration is based upon the classical theory of thin-walled beams of non-deformable cross-section. The first-order sensitivity variation of the frequencies is derived with...
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A study of cavitation erosion resistance of an ion nitrided titanium alloy by means of the vibration and rotating disk methods
PublicationIn this work, a comparative analysis of the cavitation erosion resistance of the Ti– 6.7Al–2.5Mo–1.8Cr–0.5Fe–0.25Si alloy (known as brand VT3-1) before and after lowtemperature ion nitriding is carried out. Two test methods were applied, using vibrative (ASTM G-32) and rotating disk rigs, respectively. The kinetic dependences of the erosive destruction of samples of titanium alloy VT3-1 in the initial state, after ion nitriding...
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Long-Term Impact of Wind Erosion on the Particle Size Distribution of Soils in the Eastern Part of the European Union
PublicationWind erosion is the leading cause of soil degradation and air pollution in many regionsof the world. As wind erosion is controlled by climatic factors, research on this phenomenon isurgently needed in soil and land management in order to better adapt to climate change. In thispaper, the impact of wind erosion on the soil surface in relation to particle size distribution wasinvestigated. Changes in percentage of sand, silt and...
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Preliminary design of the last stage of supercritical steam turbine and proposition of anti-erosion coating for blades surface
PublicationIn this article a preliminary design of the last stage of supercritical steam turbine has been presented. A computational model of supercritical thermal cycle has been created in order to determine steam parameters at the stage inlet and outlet. The model was based on the structure of German coal-fired power plant Datteln 4. Further steam-flow parame-ters and dimensions of stator and rotor blades have been calculated analytically....
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Modelling reinforced concrete beams under mixed shear-tension failure with different continuous FE approaches
PublicationThe paper presents quasi-static numerical simulations of the behaviour of short reinforced concrete beams without shear reinforcement under mixed shear-tension failure using the FEM and four various constitutive continuum models for concrete. First, an isotropic elasto-plastic model with a Drucker-Prager criterion defined in compression and with a Rankine criterion defined in tension was used. Next, an anisotropic smeared crack...
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Limits of enhanced of macro- and meso-scale continuum models for studying size effect in concrete under tension
PublicationThe paper investigates a mechanical quasi-static size effect in concrete during splitting tension at the macro- and meso-level. In experiments, five different diameters of cylindrical concrete specimens were tested. Twodimensional plane strain finite element (FE) simulations were carried out to reproduce the experimental size effect. The size effect in experiments by Carmona et al. was also simulated. Two enhanced continuum concrete...
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Modelling of reinforced concrete beams under mixed shear-tension failure with different continuous FE approaches
PublicationW artykule omówiono wyniki modelowania numerycznego MES zachowania się wysokich belek żelbetowych podczas zniszczenia mieszanego ścinanie-rozciąganie. Obliczenia wykonano stosując różne modele dla betonu rozszerzone o długość charakterystyczną mikrostruktury w oparciu o teorie nielokalna. Otrzymano dobrą zgodność z wynikami doświadczalnymi.