1921. Disordered eating attitudes, depressive symptomatology and alcohol consumption in young athletesUroš Perko, Maša Černelič Bizjak, 2022, izvirni znanstveni članek Povzetek: Purpose: The aim of the study was to investigate the prevalence of disordered ea-ting behaviours and attitudes in Slovenian male and female categorized athletes in relation to depressive symptoms and their alcohol consumption. Methods: The sample included 198 categorized athletes between 18 and 20 years of age. The Eating Attitude Test, the Center for Epidemiologic Studies Depression Scale, and the Alcohol Use Disorders Identification Test were used to measure disordered eating behaviours, level of depression, and alcohol use, respectively.Results: Significant differences were found between female and male at-hletes, with female athletes reporting higher levels of disordered eating atti-tudes and depressive symptoms. 13.90% of athletes reported clinically signi-ficant eating disorder symptoms, 40% reported clinically significant depres-sive symptoms, and 10.50% reported risky alcohol use.Results also showed that athletes with higher eating disorder attitudes had higher depressive levels.Conclusion: These findings have important practical value and point to the importance of building a professional team trained to recognize mental health problems in athletes in order to provide appropriate help.
Ključne besede: disordered eating behaviours, athletes, depression, alcohol consumption
Objavljeno v DiRROS: 15.04.2024; Ogledov: 458; Prenosov: 251
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1924. Experimental investigation of the shear force capacity of prismatic cross laminated timber beamsHenrik Danielsson, Tomaž Pazlar, Erik Serrano, Boris Azinović, 2024, izvirni znanstveni članek Povzetek: Experimental tests of Cross Laminated Timber (CLT) under in-plane beam loading conditions are presented. The influence of the element layup, the individual lamination width, and the beam overhang at the supports on the shear force capacity was investigated. All the CLT beams had the same gross cross section, and a 4-point-bending test setup was used. The experimentally determined load-bearing capacities are compared with the load-bearing capacities resulting from analytical methods proposed for structural design, focusing on shear failure in the crossing areas of flatwise bonded laminations (shear failure mode III). The test results indicate no or very small influence of the element layup and the lamination width on the shear force capacity. These results partly contradict the predictions of the proposed design methods. Of the three studied beam geometry parameters, the beam overhang at the support had the greatest influence on the load-bearing capacity.
Ključne besede: cross laminated timber, CLT, beam, shear testing, shear capacity, design methods
Objavljeno v DiRROS: 15.04.2024; Ogledov: 499; Prenosov: 266
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1925. Poročilo : Makro in mikro analiza vzorcev lesa za identifikacijo (javor)Jožica Gričar, Gregor Skoberne, Peter Prislan, 2024, elaborat, predštudija, študija Ključne besede: gozdarstvo, les, makro analize, mikro analize, javor, identifikacija
Objavljeno v DiRROS: 15.04.2024; Ogledov: 533; Prenosov: 130
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1926. Thermal characterisation of the cooling phase of post-flashover compartment firesAndrea Lucherini, Balša Jovanović, Jose L. Torero, Ruben Van Coile, Bart Merci, 2024, izvirni znanstveni članek Povzetek: The main characteristics of the cooling phase of post-flashover compartment fires are studied using a simplified first-principles heat transfer approach to establish key limitations of more traditional methodologies (e.g., Eurocode). To this purpose, the boundary conditions during cooling are analysed. To illustrate the importance of a first-principles approach, a detailed review of the literature is presented followed by the presentation of a simplified numerical model. The model is constructed to calculate first-order thermal conditions during the cooling phase. The model is not intended to provide a precise calculation method but rather baseline estimates that incorporate all key thermal inputs and outputs. First, the thermal boundary conditions in the heating phase are approximated with a single (gas) temperature and the Eurocode parametric fire curves, to provide a consistent initial condition for the cooling phase and to be able to compare the traditional approach to the first- principles approach. After fuel burnout, the compartment gases become optically thin and temperatures decay to ambient values, while the compartment solid elements slowly cool down. For simplicity, convective cooling of the compartment linings is estimated using a constant convective heat transfer coefficient and all linings surfaces are assumed to have the same temperature (no net radiative heat exchange). All structural elements are assumed to be thermally thick. While these simplifications introduce quantitative errors, they enable an analytical solution for transient heat conduction in a semi-infinite solid that captures all key heat transfer processes. Comparisons between the results obtained using both approaches highlight how, even when considering the same fire energy input, the thermal boundary conditions according to the Eurocode parametric fire curves lead to an increase energy accumulated in the solid after fuel burnout and a delay in the onset of cooling. This is not physically correct, and it may lead to misrepresentation of the impact of post-flashover fires on structural behaviour.
Ključne besede: cooling phase, fire decay, fire dynamics, compartment fires, structural fire engineering, fire safety
Objavljeno v DiRROS: 15.04.2024; Ogledov: 545; Prenosov: 241
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1927. An experimental apparatus for bench-scale fire testing using electrical heating padsAleksandra Seweryn, Andrea Lucherini, Jean-Marc Franssen, 2024, izvirni znanstveni članek Povzetek: This research study concerns an experimental, budget-friendly, electricity- powered apparatus for bench-scale fire testing. The apparatus consists of various elements, of which the most important are ceramic heating pads, used to impose heat fluxes on exposed surfaces of specimens. The test method allows to control the heating pads’ temperature and to adjust the distance between the heating pads and the specimen to obtain well-defined heat fluxes up to 50–60 kW/m2. Higher heat fluxes and temperatures can be obtained by setting the heating pads in full power mode, with or without the use of a thermal shield, which can lead to heat fluxes up to 150 kW/m2. The heating and thermal boundary conditions imposed by the apparatus are characterised and discussed, and the thickness of the convective boundary layer at the heating pads’ surface is estimated significantly lower than in the case of gas- fired radiant panels. The performance of the apparatus is analysed for various conditions: controlling the temperature of the heating pads, in an open environment or with the presence of thermal shields, and in full power mode. A few examples of application of the apparatus to fire test typical construction materials (steel and glass) are also presented. These results emphasise the well-defined heating conditions in temperature-controlled mode. The study finally discusses the advantages and limitations of the apparatus, as well as many possibilities of future applications and improvement for future research studies.
Ključne besede: radiant panels, fire testing, heat transfer, heat flux, electrical heating pads, thermal boundary conditions
Objavljeno v DiRROS: 15.04.2024; Ogledov: 463; Prenosov: 847
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1928. Influence of test methodology on the characterization of the parallel-to-grain timber embedment strength and foundation modulus of dowelsCaroline D. Aquino, Rodrigues Leonardo G., Michael Schweigler, Meta Kržan, Zheng Li, Jorge M. Branco, 2024, izvirni znanstveni članek Povzetek: A reliable determination of the embedment strength and foundation modulus of timber elements is critical for the design and safety assessment of joints in timber structures. However, the existence of various test configurations for characterising the embedding properties of large diameter steel fasteners in timber elements poses challenges in directly comparing and utilising available test data. This paper aims to provide an insight into the influence of embedment property test methods, comparing experimental results from different test setups within the guidelines of the EN 383 and ASTM D 5764-97a standards for European softwood species, Scots pine wood (Pinus sylvestris) and Norway spruce (Picea abies). In addition to the test guidelines, the thickness of the specimen and the application of the load was evaluated within the protocols. A comprehensive statistical analysis was performed to identify statistically significant differences between the groups evaluated. The results of the analysis revealed disagreement between the standards in the evaluation of the strength of the embedding, highlighting the potential bias inserted by the experimental setup and protocol. Furthermore, it was proven that the thickness of the specimens influences both the embedding strength and the foundation modulus of the wood species tested. Finally, no distinctions were observed between tensile and compressive loading within the guidelines of the EN 383 standard.
Ključne besede: embedment strength, foundation modulus, dowel-type connections, test methods
Objavljeno v DiRROS: 15.04.2024; Ogledov: 421; Prenosov: 225
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1929. Why geopolymers and alkali-activated materials are key components of a sustainable world : a perspective contributionWaltraud M. Kriven, Cristina Leonelli, John L. Provis, Aldo R. Boccaccini, Cyril Attwell, Vilma Ducman, Claudio Ferone, Sylvie Rossignol, Tero Luukkonen, Jannie S. J. Van Deventer, José V. Emiliano, Jérôme E. Lombardi, 2024, izvirni znanstveni članek Povzetek: This perspective article delves into the transformative potential of alkali-activated materials, acid-activated materials, and geopolymers in mitigating climate change and market challenges. To harness the benefits of these materials, a comprehensive strategy is proposed. This strategy aims to integrate these materials into existing construction regulations, facilitate certification, and promote market access. Emphasizing research and innovation, the article advocates for, increased funding to refine the chemistry and production of these materials, prioritizing low-cost alternatives and local waste materials. Collaboration between academia and industry is encouraged to expedite technological advances and broaden applications. This article also underscores the need to develop economic and business models emphasizing the long-term benefits of these materials, including lower life-cycle costs and reduced environmental impact. Incentivizing adoption through financial mechanisms like tax credits and subsidies is suggested. The strategy also includes scaling up production technology, fostering industrial collaboration for commercial viability, and developing global supply chains. Educational programs for professionals and regulators are recommended to enhance awareness and adoption. Additionally, comprehensive life-cycle assessments are proposed to demonstrate environmental benefits. The strategy culminates in expanding the applications of these materials beyond construction, fostering international collaboration for knowledge sharing, and thus positioning these materials as essential for sustainable construction and climate change mitigation.
Ključne besede: geopolymers, alkali activated materials, perspective
Objavljeno v DiRROS: 15.04.2024; Ogledov: 454; Prenosov: 476
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1930. Utilisation of reused steel and slag : analysing the circular economy benefits through three case studiesGenesis Camila Cervantes Puma, Adriana Salles, Janez Turk, Viorel Ungureanu, Luís Bragança, 2024, pregledni znanstveni članek Povzetek: This research explores sustainable construction practices focusing on material reuse, specifically reclaimed structural steel and slag. In general, the building stock is not designed for deconstruction, and material recovery for reuse at the end of life of buildings is complex and challenging. The study evaluates the benefits of content reuse through a thorough analysis of three case studies— BedZED eco-friendly housing, Angus Technopôle building, and the use of steel slag aggregate in road construction. It highlights the value of reclaimed structural steel and by-products like steel slag in waste reduction, energy conservation, and resource preservation. The BedZED case study showcases recycled steel’s cost-effectiveness and economic viability in construction, while the Angus Technopôle building exemplifies the adaptive reuse of an old steel frame building. Additionally, the third case study showcases the benefits of using Electric Arc Furnace C slag in asphalt-wearing courses, highlighting the reduction in greenhouse gas emissions and environmental impact. The versatility of reclaimed structural steel and slag is evident in integrating material reuse in building construction and road infrastructure. These case studies illustrate the potential for reusing steel and its by-products in various construction contexts, from eco-friendly housing to road development. Therefore, the study aims to demonstrate the feasibility and benefits of sustainable practices within the construction industry by showcasing the successful incorporation of reclaimed steel and slag in these projects. Considering the significant contributions of building construction to global greenhouse gas emissions, raw material extraction, and waste production, the study advocates for adopting circular economy (CE) principles within the construction industry. Finally, the analysis of case studies underscores the advantages of reclaimed structural steel and the valorisation of steel slag through the lens of CE and their contribution to sustainable development.
Ključne besede: circular economy, reused steel, steel slag aggregate, reclaimed steel, steel members
Objavljeno v DiRROS: 12.04.2024; Ogledov: 488; Prenosov: 207
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