Search results for: stress measurement
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The correlation of fractal dimension to fracture surface slope for fatigue crack initiation analysis under bending-torsion loading in high-strength steels
PublicationIn this study, the fractal dimension of fatigue fracture surfaces is investigated in order to find an alternative failure loading indicator. Some of many metrological factors are generalized by reducing the fracture surface structure to one factor and develop an entire fracture surface procedure by analyzing the impact of surface slope and calculation resolution. Three notched geometries are studied under cyclic bending-torsion:...
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Isoprostanes-Biomarkers of Lipid Peroxidation: Their Utility in Evaluating Oxidative Stress and Analysis
PublicationIsoprostanes (IsoPs) are key biomarkers for investigating the role of free radical generation in the pathogenesis of human disorders. To solve IsoPs-related problems with regard to isoprostanes, analytical tools are required. This paper reviews the problems and trends in this field focusing on the methodology for assaying biomarkers in exhaled breath condensate (EBC) samples. A large amount of work has been done in the qualitative...
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Screw displacement pile shaft deformations measured by vibrating wire and fiber optic systems during a static load test
PublicationThis paper describes a full scale static load test performed on a 400 mm diameter screw displacement pile equipped with four different strain measuring systems. Three types of vibrating wire strain gauges (VWSG) were used: global - retrievable, local attached to steel pipe and local concrete embedded. The fourth system was distributed fiber optic sensors based on Rayleigh back scattering (DFOS) - three in the pile cross section....
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THE PROBLEM OF AIRFLOW AROUND BUILDINGS CLUSTERS IN DIFFERENT CONFIGURATIONS
PublicationIn the paper, the authors discuss the construction of a model of an exemplary urban layout. Numerical simulation has been performed by means of a commercial software Fluent using two different turbulence models: the popular k-ε realizable one, and the Reynolds Stress Model (RSM), which is still being developed. The former is a 2-equations model, while the latter – is a RSM model – that consists of 7 equations. The studies have...
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Short-term measurement of physiological parameters - child (2)
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (5 minutes) measurements of physiological parameters were performed on the healthy...
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Fatigue fracture morphology of AISI H13 steel obtained by additive manufacturing
PublicationThe paper focuses on researching the effect of fatigue loading on metallic structure, lifetime, and fracture surface topographies in AISI H13 steel specimens obtained by selective laser melting (SLM). The topography of the fracture surfaces was measured over their entire area, according to the entire total area method, with an optical three-dimensional surface measurement system. The fatigue results of the SLM 3D printed steel...
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Surface treatment of C80U steel by long CO2 laser pulses
PublicationThe paper presents the results of laser-melted C80U steel. The processed steel was placed between two permanent magnets and laser beam whose scanning velocity was 10 mm/s. CO2 laser beam was working in pulse mode. Pulses were generated at 100% of the average preset power of 700W, with 45 ms irradiation, zero interval between pulses and beginning of pulse repetition upon the achievement of the average laser power. During the operation,...
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Determination of stepped plate thickness distribution using guided waves and compressed sensing approach
PublicationGuided waves recently have attracted significant interest as a very promising research area. The signals registered by a specially designed sensor network are processed to assess the state of the tested structure. Despite the constant development of novel damage detection algorithms employing guided waves, the phenomenon of wave propagation still needs detailed recognizing and understanding for the further progress of non-destructive...
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Short-term measurement of physiological parameters - teenager (25 min)
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (25 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (5 min)
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (15 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (10 min)
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (15 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - adult (35 min)
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (35 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (15 min)
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (15 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - adult (20 min)
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (20 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (5 min)
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (5 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (10 min)
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (10 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (15 min)
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (15 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (30 min)
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (25 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (40 min)
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (40 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (20 min)
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (20 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (25 min)
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (25 minutes) measurements of physiological parameters were performed on the healthy...
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Stress Monitoring System for Individuals with Autism Spectrum Disorders
PublicationIn this article, a stress monitoring system tailored for individuals with Autism Spectrum Disorders (ASD) and developed for the educational institution is presented. People with ASD face problems with effective stress management due to their high self-perceived levels of stress, poor ability to cope with it, and dificulties with the accurate detection of the source of stress. Consistently, being able to measure stress appears to...
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Short-term measurement of physiological parameters - teenager (5 min) - 3.series
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (5 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (5 min) 7.series
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (5 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (20 min) 2.series
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (20 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (10 min)_3.series
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (10 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (5 min) 6.series
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (5 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (5 min) - 2.series
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (5 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (5 min) - 5.series
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (5 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (5 min) - 6.series
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (5 minutes) measurements of physiological parameters were performed on the healthy...
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Short-term measurement of physiological parameters - teenager (5 min) - 4.series
Open Research DataThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Short-term (5 minutes) measurements of physiological parameters were performed on the healthy...
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On the effective properties of foams in the framework of the couple stress theory
PublicationIn the framework of the couple stress theory, we discuss the effective elastic properties of a metal open-cell foam. In this theory, we have the couple stress tensor, but the microrotations are fully described by displacements. To this end, we performed calculations for a representative volume element which give the matrices of elastic moduli relating stress and stress tensors with strain and microcurvature tensors.
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Efficacy of coping with work-related stress by firemen
PublicationThe aim of this study was efficacy of coping with work-related stress by firemen with reference to subjective health evaluation. Theoretical model of process of stress by Lazarus was applied. The group consistent of 230 line-duty firemen. Participation in traumatic events and sense of coherence both directly and indirectly, by stress, affected the health among firemen. In stress confrontation a wider array of task and emotional...
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On refined constitutive equations in the six-field theory of elastic shells
PublicationWithin the resultant six-field shell theory, the second approximation to the complementary energy density of an isotropic elastic shell undergoing small strains is constructed. In this case, the resultant drilling couples are expressed explicitly by the stress resultants and stress couples as well as by amplitudes of the quadratic and cubic distributions of an intrinsic deviation vector. The refined 2D strain-stress and stress-strain...
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The effect of job-related stress on psychological well-being = Wpływ stresu zawodowego na dobrostan psychiczny
PublicationThe aim of the investigation was to evaluate the effect of job stress factors on psychological well-being of firemen. Goldberg's GHQ-12 for well-being evaluation, the Perceived Job Stress Questionnaire by Dudek et al. for job stress assessment, and indicator of participation in traumatic events were used. 19% of the firemen were qualified to the group with increased risk of mental disorders. Occupational stress had a strong impact...
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Stress analysis of a strip under tension with a circular hole
PublicationThe paper addresses stress analysis of a strip with a circular hole under uniform uniaxial tension based oncircumferential stress expressionρπ. Stresses are analyzed in the infinite-length strips under tension with holes, the ratioof the hole radiusa to the strip half-widthb is either equal to:κ =a/b = 0.1 orκ = 0.5. Circumferential stresses aredetermined in selected cross-sections of the strip. The stress diagrams display local...
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Nonlinear FEM 2D failure onset prediction of composite shells based on 6-parameter shell theory
PublicationWithin the framework of the nonlinear 6-parameter shell theory with the drilling rotation and asymmetric stress measures, the modifications of Tsai-Wu and Hashin laminate failure initiation criteria are proposed. These improvements enable to perform first ply failure estimations taking into account the non-symmetric stress measures. In order to check the validity of the proposed criteria, finite element analyses are performed with...
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NON-LINEAR MASTIC CHARACTERISTICS BASED ON THE MODIFIED MSCR (MULTIPLE STRESS CREEP RECOVERY) TEST
PublicationMastic containing asphalt in its composition is an example of a viscoelastic material. It is an effective binder in asphalt. It consists of a filler (<0.063 mm) and asphalt mixed in the right proportions. Just like in asphalt, its response depends on the temperature level, the load and stress time. Changing the stress stiffness of the mastic affects the non-linear course of the stress-strain relationship. Modelling of the non-linear...
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Comparison of different one-parameter damage laws and local stress-strain approaches in multiaxial fatigue life assessment of notched components
PublicationThis paper aims to compare the predictive capabilities of different one-parameter damage laws and local stress-strain approaches to assess the fatigue lifetime in notched components subjected to proportional bending-torsion loading. The tested fatigue damage parameters are defined using well-known stress-based, strain-based, SWT-based and energy-based relationships. Multiaxial cyclic plasticity at the notch-controlled process zone...
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Corrigendum to “An investigation on residual stress and fatigue life assessment of T-shape welded joints” [Eng. Fail. Anal. 141 (2022) 106685]
PublicationThis paper aims to quantitatively evaluate the residual stress and fatigue life of T-type welded joints with a multi-pass weld in different direction. The main research objectives of the experimental test were to test the residual stress by changing direction along with multiple wielding passes and determine the fatigue life of the welded joints. The result shows that compressive residual stress increases in the sample gradually...
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An investigation on residual stress and fatigue life assessment of T-shape welded joints
PublicationThis paper aims to quantitatively evaluate the residual stress and fatigue life of T-type welded joints with a multi-pass weld in different direction. The main research objectives of the experimental test were to test the residual stress by changing direction along with multiple wielding passes and determine the fatigue life of the welded joints. The result shows that compressive residual stress increases in the sample gradually...
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Central-force decomposition of spline-based modified embedded atom method potential
PublicationCentral-force decompositions are fundamental to the calculation of stress fields in atomic systems by means of Hardy stress. We derive expressions for a central-force decomposition of the spline-based modified embedded atom method (s-MEAM) potential. The expressions are subsequently simplified to a form that can be readily used in molecular-dynamics simulations, enabling the calculation of the spatial distribution of stress in...
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Large deformation finite element analysis of undrained pile installation
PublicationIn this paper, a numerical undrained analysis of pile jacking into the subsoil using Abaqus software suit has been presented. Two different approaches, including traditional Finite Element Method (FEM) and Arbitrary Lagrangian–Eulerian (ALE) formulation, were tested. In the first method, the soil was modelled as a two-phase medium and effective stress analysis was performed. In the second one (ALE), a single-phase medium was assumed...
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FEM approach to estimate the behaviour of biocomposite metal-surface coating system
PublicationA three dimensional (3D) model of biocomposite metal-surface coating system, which is influenced byknown external forces, is proposed. This model consists of the metallic substrate (Ti6Al4V) and thehydroxyapatite (HA) coating. Using FEM (finite element method), strain-stress maps of model weregenerated for investigating relations between the extreme stress of HA coating and the magnitude ofexternal force and the thickness of the...
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Assessment of Tensile Strength Reserve of Asphalt Mixtures at Low Temperatures
PublicationDuring winter conditions, low-temperature cracks develop at the surface of the asphalt pavement when tensile thermal stress induced in the asphalt layer during cooling equals and exceeds the tensile strength of the material. The paper presents the results of tensile strength reserve assessment of asphalt mixtures with neat and SBS-polymer modified bitumen application. The tensile strength reservewas calculated as difference between...
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Local buckling of thin-walled channel member flange made of aluminum alloy
PublicationThe paper deals with local stability of the thin-walled compressed flange of channel columns and beams made of aluminum alloy. The aim of paper is to find critical stress of local buckling of the flange member taking into account the web-flange interaction in linear and nonlinear elastic range of the member material. The governing differential equation of the problem is derived with aid of the principle of stationary total potential...
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Propagation of acoustic pulses in some fluids with yield stress
PublicationThis study is devoted to the derivation of approximate equations governing acoustic pulses in flows with yieldstress, including some time-dependent flows with a slow dependence on time of yield stress and apparent viscosity. Themodeling of yield stress and apparent viscosity in the vicinity of a zero deformation rate allows us to consider a thixotropicfluid as a Bingham plastic with coefficients that are dependent on time. The...
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The elasto-plastic numerical study of crack initiation in notched PMMA specimens under uniaxial loading conditions – Tension and torsion
PublicationThis paper presents the results of FEM numerical calculations aimed at describing the plastic strain and stress fields under critical loading conditions: tensile force or torsional moment. The calculations were carried out with reference to the results of experimental tensile and torsional tests of flat PMMA specimens weakened with V-notches of different root radii: 0.5, 2 and 10 mm. The procedure for conducting nonlinear numerical...
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A hyperelastic model for soils with stress-induced and inherent anisotropy
PublicationIn this paper, modelling of the superposition of stress-induced and inherent anisotropy of soil small strain stiffness is8presented in the framework of hyperelasticity. A simple hyperelastic model, capable of reproducing variable stress-induced9anisotropy of stiffness, is extended by replacement of the stress invariant with mixed stress–microstructure invariant to10introduce constant inherent cross-anisotropic component. A convenient...
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Assessment of unusual failure in crankshaft of heavy-duty truck engine
PublicationThe unusual premature failure of a heavy-duty truck engine crankshaft has been the subject of a rigorous study, and this manuscript describes it in detail. The failure was happened to begin with the growth of the crack from the surface defects, in the form of the clusters of non-metallic inclusions, in the lubrication hole zone of the first main journal, which was the stress concentration zone. A series of experiments including...