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Search results for: STRESS CONCENTRATION FACTOR
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Mechanical Properties of Bio-Composites Based on Epoxy Resin and Nanocellulose Fibres
PublicationThe aim of our research was to investigate the effect of a small nanocellulose (NC) addition on an improvement of the mechanical properties of epoxy composites. A procedure of chemical extraction from pressed lignin was used to obtain nanocellulose fibers. The presence of nanoparticles in the cellulose pulp was confirmed by FTIR/ATR spectra as well as measurement of nanocellulose particle size using a Zetasizer analyzer. Epoxy...
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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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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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The effect of raw material type on endotoxin content .
Open Research DataThe datasets contain the results of determining the effect of raw material type on endotoxin content as well as the effect of purification methods. The endotoxin concentration was determined using the PyroGene Recombinant Factor C Endpoint Fluorescent Assay. Beckmann-Kenko sodium alginate and Chemat sodium salt of alginic acid were used for the assays....
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The Dominant Influence of Plastic Deformation Induced Residual Stress on the Barkhausen Effect Signal in Martensitic Steels
PublicationThe paper presents the results of investigation of the influence of plastic deformation on the magnetic properties of martensitic steel (P91 grade). The properties of the hysteresis loops as well as of the Barkhausen effect (BE) signal are analysed for both tensile and compressive loading up to ε = 10% of plastic deformation. The choice of the steel and of the deformation range is unique, since for such combination one can expect...
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Gender as a moderator between Present-Hedonistic time perspective and depressive symptoms or stress during COVID-19 lock-down
PublicationAlthough numerous studies have addressed the impact of the COVID-19 lock-downs on psychological distress, scarce data is available relating to the role of Present-Hedonistic (PH) time perspective and gender differences in the development of depressive symptoms and stress during the period of strict social distancing. We hypothesized that gender would moderate the relationship between PH and depressiveness or stress levels, such...
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Mathematical modeling and prediction of pit to crack transition under cyclic thermal load using artificial neural network
PublicationThe formation of pitting is a major problem in most metals, which is caused by extremely localized corrosion that creates small holes in metal and subsequently, it changes into cracks under mechanical load, thermo-mechanical stress, and corrosion process factors. This research aims to study pit to crack transition phenomenon of steel boiler heat tubes under cyclic thermal load, and mathematical modeling...
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Discussion of Derivability of Local Residual Stress Level from Magnetic Stray Field Measurement
PublicationThe NDT procedure dubbed ‘metal magnetic memory’ method and the related ISO 24497 standard has found wide industrial acceptance in some countries, mainly in Russia and China. The method has been claimed by some researchers (Roskosz and Bieniek in NDT&E Int 45:55–62, 2012; Wilson et al. in Sens Actuators A 135:381–387, 2007) as having potential for quantitative determination of local residual stress state in engineering structures,...
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Psychosocial risks associated with the profession of train driver
PublicationExcellent competencies as well as a good physical and mental health are required in train drivers’ profession. Despite the changes in the structure of employment the train drivers above 46 years and job tenure longer than 30 years are the largest group. The generation gap is becoming more pronounced, and its fulfilment will not be easy. It is related not only to training of new personnel but also promotion of healthy work environment...
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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...