Browsing by Type "posted-content"

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  • Publication
    Investigation of the Influence of Some Parameters on the Process of Color Laser Marking
    (2023)
    Emil Yankov
    ;
    Lazov, Lyubomir 
    ;
    Teirumnieks, Edmunds 
    ;
    Nikolay Angelov
    The research and development of laser marking technology offers numerous advantages and applications in a variety of industries, from manufacturing and electronics to healthcare and beyond. In industries such as aerospace and automotive, where components must adhere to strict regulatory standards, laser marking can provide the necessary traceability and compliance. Investing in its research and development improves precision, efficiency and innovation, ultimately contributing to advancements in various sectors and driving economic growth.For this purpose, various surface treatment methods are being studied, including laser marking. As can be seen from our previous studies and those of other authors, laser marking of steel surfaces is a complex process and depends on the complex relationships between a number of technological parameters. In this study, we focus on the influence of four of them (parameters: processing speed, laser pulse frequency, pitch between raster lines during laser processing and energy density). During the experiments, the raster step was varied in the range of 20 µm to 80 µm, the velocity was in the range of 25 mm/s to 125 mm/s, and the density was in the range of 5.82 J/mm2 to 29.12 J/mm2. The experiments were done for three frequencies - 20 kHz, 50 kHz and 100 kHz. All these intervals can be realized in the real production. The change of the four investigated parameters was analyzed in relation to the obtained roughness in the processing zone as a function of these four technological parameters and was compared with the corresponding color coordinates of the obtained color markings in these zones. It has been proven that each specific color is associated with surface structural changes as a result of the interaction between laser radiation with a certain laser energy density and the processed material. The present study is a small contribution to the topic of laser color marking of various materials, enabling the production of new surface properties.
  • Publication
    “Resource Portfolio” and Total Capital of Different Social Classes in the Modern Society of Latvia
    (2021)
    Vera Komarova
    ;
    Iveta Mietule
    ;
    Iluta Arbidāne
    ;
    Vladas Tumalavičius
    The aim of this study is to investigate “resource portfolios” and total capital, as well as the degree of those resources capitalization, which representatives of different social classes in the modern Latvia have at their disposal. The amount and structure of “resource portfolio” and total capital of different social classes studied using the resource-asset-capital approach. The article presents results of the sociological survey of social stratification in modern Latvia on the example of its one region – Latgale (2019, n = 798, representative sample of the adult population), identifying social classes based on two objective (income and education) and one subjective (self-identification of respondents) criteria. Based on the example of the lower working class and the middle class, the authors proved that representatives of these polar social classes have a total capital of different amount, which is determined by two main reasons: 1) the lower working class has statistically significantly smaller “resource portfolio” than the middle class; 2) the lower working class is not so successful as the middle class in activating the resources at their disposal, turning them into their capital. These statistically significant two-level differences have to be considered when pursuing social policies on reducing differences between social classes.