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Published in DiRROS: 21.08.2025; Views: 314; Downloads: 152
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Abstract: Multi-walled CNTs with an average diameter of about 80 nm, a length of several micrometers and surface area (SBET) of 100 m2 g–1 were obtained by pyrolysis of low-density polyethylene waste. The potential of the resulting MWCNTs material to purify water containing organic dyes was tested with Bezaktiv Blau HE-RM (BB) and Bezaktiv Rot S-3B (BR) reactive dyes. 200 mg L–1 MWCNT material was used to follow the adsorption of 30 mg L–1, 40 mg L–1, 50 mg L–1 and 60 mg L–1 BB and BR at pH 3 and a temperature of ~25 °C. The results have shown that this material has a high potential as a sorbent, and its adsorption capacity of 257 mg g–1 (for Bezaktiv BlauHE-RM) and 213 mg g–1 (for Bezaktiv Rot) is close to some commercial MWCNTs and functionalized MWCNT-based adsorbents. The adsorption process was very fast, reaching 80–90% of the dye removal in 10–15 minutes, and the equilibrium time was reached in 40–60 minutes. The adsorption isotherm showed that the Langmuir model was more suitable than the Freundlich model for describing the adsorption properties of the pollutants.
Keywords: adsorption, anionic dyes, upcycling plastic waste, carbon nanotubes
Published in DiRROS: 21.08.2025; Views: 377; Downloads: 166
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Abstract: Sports events are the main part of the organizational culture of sport with an impact on the promotion of the environ-ment in which they take place and also deve-lop tourism and other economies. The impacts of major sports events are a direct or indirect result of their management and organization and can be negative or positive. In accordance with this, the purpose of this article is to pre-sent the comprehensive conceptual framework (model) of the sports events management. To design the research, we used the methodology of writing a conceptual paper and the method approach called "model paper" which seeks to build a theoretical framework that predicts re-lationships that provides a bridge or connec-tion between different concepts and scientific disciplines. The developed conceptual frame-work presented in thisarticle comprehensively coverstheissueof management of major sports events and takes into account the specifics or characteristics of this type of project. The mu-tual coherence and connectivity of threemo-dels(strategic management models, projectmanagement methodology, sports event mana-gement theory and practice) define the general management model of a major sport events which holistically covers the problem of mana-gement of large sports events and provides the user of the framework with direct guidance on activities and requirements formanaging of this type of projects.
Keywords: major sport event, strategic management, project management, general framework, benefits of sport events
Published in DiRROS: 21.08.2025; Views: 326; Downloads: 156
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Abstract: This paper deals with finite cubic (3-regular) graphs whose automorphism group acts transitively on the edges of the graph. Such graphs split into two broad classes, namely arc-transitive and semisymmetric cubic graphs, and then these divide respectively into 7 types (according to a classification by Djoković and Miller (1980) [17]) and 15 types (according to a classification by Goldschmidt (1980) [23]), in terms of certain group amalgams. Such graphs of small order were previously known up to orders 2048 and 768, respectively, and we have extended each of the two lists of all such graphs up to order 10000. Before describing how we did that, we carry out an analysis of the 22 amalgams, to show which of the finitely-presented groups associated with the 15 Goldschmidt amalgams can be faithfully embedded in one or more of the other 21 (as subgroups of finite index), complementing what is already known about such embeddings of the 7 Djoković-Miller groups in each other. We also give an example of a graph of each of the 22 types, and in most cases, describe the smallest such graph, and we then use regular coverings to prove that there are infinitely many examples of each type. Finally, we discuss the asymptotic enumeration of the graph orders, proving that if $f_{\mathcal C}(n)$ is the number of cubic edge-transitive graphs of type ${\mathcal C}$ on at most $n$ vertices, then there exist positive real constants $a$ and $b$ and a positive integer $n_0$ such that $n^{a \log(n)} \le f_{\mathcal C}(n) \le n^{b \log(n)}$ for all $n\ge 0$.
Keywords: groups, graphs, symmetry, amalgams, cover
Published in DiRROS: 21.08.2025; Views: 252; Downloads: 127
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Keywords: warm-mix recycled asphalt mortar, freeze-thaw cycle, reflection cracking characteristics, digital image correlation technology, cracking damage factor
Published in DiRROS: 20.08.2025; Views: 402; Downloads: 193
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