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Povzetek: Direct-co-direct product $G\circledast H$ of graphs $G$ and $H$ is a graph on the vertex set $V(G)\times V(H)$. Two vertices $(g,h)$ and $(g',h')$ are adjacent if $gg'\in E(G)$ and $hh'\in E(H)$ or $gg'\notin E(G)$ and $hh'\notin E(H)$. We show that if at most one factor of $G\circledast H$ is connected, then the distance between two vertices of $G\circledast H$ is bounded by three unless some small number of exceptions. All the exceptions are completely described which yields the distance formula.
Ključne besede: direct-co-direct product, distance, eccentricity, disconnected graphs
Objavljeno v DiRROS: 19.03.2024; Ogledov: 68; Prenosov: 39
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Povzetek: To foster sustainable development, the environmental impacts of the construction sector need to be reduced substantially. Life cycle assessment (LCA) is the established methodology for the quantification of environmental impacts, and therefore has been increasingly applied to assess the environmental performance of buildings. By coupling LCAs with digital design tools, e.g., building information modeling (BIM), the identification of environmental hotspots and their mitigation is possible during the design process. The objective of the study is to identify the current integration approaches, and determine the pros and cons of the integration process from different viewpoints, namely, technical, informational, organizational and functional issues. Therefore, a comprehensive systematic literature review (SLR) was performed. We identified 60 relevant BIM-LCA case studies and analyzed the applied BIM-LCA workflows in detail. A total of 16 of the reviewed studies applied LCA during the early design stage. These studies used a manual or semiautomatic data exchange between the BIM models and LCA tools. In most cases, contemporary BIM-LCA workflows utilized conventional spreadsheets (e.g., Excel sheets in 16 cases). However, the analysis shows that an automated link between LCA and BIM can be achieved when overcoming the technical, organizational and informational issues discussed in the paper. This could enable the streamlining of LCA applications in design practice, and thus support the necessary improvements in the environmental performance of buildings.
Ključne besede: building information modeling (BIM), life cycle assessment (LCA), systematic literaturereview (SLR), environmental product declarations (EPD), workflow, bill of quantities (BoQ)
Objavljeno v DiRROS: 05.03.2024; Ogledov: 141; Prenosov: 45
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Povzetek: A set of vertices $X$ of a graph $G$ is a strong edge geodetic set if to any pair of vertices from $X$ we can assign one (or zero) shortest path between them such that every edge of $G$ is contained in at least one on these paths. The cardinality of a smallest strong edge geodetic set of $G$ is the strong edge geodetic number ${\rm sg_e}(G)$ of $G$. In this paper, the strong edge geodetic number of complete multipartite graphs is determined. Graphs $G$ with ${\rm sg_e}(G) = n(G)$ are characterized and ${\rm sg_e}$ is determined for Cartesian products $P_n\,\square\, K_m$. The latter result in particular corrects an error from the literature.
Ključne besede: strong edge geodetic problem, complete multipartite graph, edge-coloring, Cartesian product of graphs
Objavljeno v DiRROS: 19.02.2024; Ogledov: 127; Prenosov: 41
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Povzetek: To increase the sustainability of prefabricated timber buildings and constructions, composite timber beams with “box” cross-sections were developed in collaboration with an industry partner. They were constructed from a solid timber frame and from webs made of residual waste wood- particle boards from prefabricated timber buildings production. The developed beams’ design concepts presented in this paper were governed by architectural features of prefabricated timber buildings, geometrical limitations, available production technology, and structural demand related to various possible applications. The paper presents the results of experimental bending tests of six variations of the developed composite timber beams constructed by mechanical fasteners only. The developed design concept of composite timber beams without adhesives is beneficial compared to glued beams in terms of design for deconstruction and lower VOC emissions. The tests were conducted to study the influence of the following parameters on the beams’ mechanical behavior: (i) web material (oriented strand boards (OSBs) vs. cement-particle boards); (ii) the influence of beam timber frame design (flanges and web stiffeners vs. flanges, web stiffeners, and compressive diagonals), and (iii) the influence of stiffener–flange joint design. Besides the beams’ load-bearing capacities, their linear and non-linear stiffness characteristics were the main research interest. While adding compressive timber diagonals did not prove to significantly increase the stiffness of the beams in the case of cement-particle board webs, it increased their load-bearing capacity by enabling the failure of flanges instead of prior webs and stiffener–flange joints failure. For beams with OSB webs, failure of the bottom flange was achieved already with the “basic” timber frame design, but timber diagonals proved beneficial to increase the stiffness characteristics. Finally, mechanical characteristics of the developed beams needed in structural design for their application are provided together with further development guidelines.
Ključne besede: composite timber beam, box beam, OSB, cement-particle boards, innovative engineered wood product, experimental tests, flexural performance, mechanical fasteners, open access
Objavljeno v DiRROS: 29.05.2023; Ogledov: 252; Prenosov: 151
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Povzetek: The bottleneck in the process for increasing production of low CO2 mineral binders, based on BCSA (belite sulfoaluminate) clinkers, is the availability of Al-rich raw materials. For that purpose, a new registry of Al-containing secondary mineral residues (industrial and mine waste) has been developed and is presented in this paper. The methodology of creating the registry consists of three main steps: Gathering ideas, consolidation of ideas, and implementation. In order to achieve this, the following methodology was adopted: Analysis of similar registries by potential end-users and seeking potential solutions and tools to be used, and conducting 3 rounds of stakeholder consultations via workshops in order to determine crucial parameters and features the registry needs to contain. The key discussion points were about which data the registry needs to contain, who shall be the potential users, and what are the stakeholderʼs expectations from the registryʼs portal. Potential individual registry variables were identified as being relevant/irrelevant or available/unavailable, and potential solutions for the registrys sustainability were explored. Each Al-rich waste/residue data entry is divided into 10 slots, describing legal status, location, quantities, chemical (REE included), mineralogical, physical and radiological properties, life-cycle assessment, additional data, and data relevancy. The registry will act as a matchmaking tool between producers/holders of Al-rich secondary raw materials and potential producers of cement clinkers.
Ključne besede: cement, belite sulfoaluminate clinker, waste, by--product, deležniki
Objavljeno v DiRROS: 10.06.2022; Ogledov: 525; Prenosov: 316
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