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1403. Body composition of young soccer playersErol Kovačević, Denis Čaušević, Seth Spicer, Siniša Kovač, Ivor Doder, Slavenko Likić, Boris Metikoš, 2022, original scientific article Abstract: Purpose:The main aim of this study was to examine and analyse the body composi-tion of young soccer players across different age groups.Methods: A cross-sectional study was carried out among 126 young soccer players divided into age categories: U15 – 53 players (age=14.68±0.47); U17 – 51 players (age=16.47±0.50); U19 – 22 players (age=18.05±0.38). The subjects’ height was mea-sured using an anthropometer, while their body composition was measured using the TANITA BC-420MA digital scale. Results: On average, soccer players in the U15 group had significantly lower body height, weight, body mass index and fat free mass than U17 and U19 players, but had a higher percentage of body fat (p < 0.05). In addition to the percent of body fat mass, which tends to significantly decrease with age, the results also demonstrate significant non-linear increases in body height, weight, and lean body composition concurrent with the players’ ages.Conclusion:These results indicate that younger soccer players have lower abso-lute values of morphological characteristics compared to senior players. Keywords: BMI, anthropometry, fitness, body fat, soccer Published in DiRROS: 15.04.2024; Views: 318; Downloads: 219
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1404. Disordered eating attitudes, depressive symptomatology and alcohol consumption in young athletesUroš Perko, Maša Černelič Bizjak, 2022, original scientific article Abstract: 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. Keywords: disordered eating behaviours, athletes, depression, alcohol consumption Published in DiRROS: 15.04.2024; Views: 345; Downloads: 206
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1407. Experimental investigation of the shear force capacity of prismatic cross laminated timber beamsHenrik Danielsson, Tomaž Pazlar, Erik Serrano, Boris Azinović, 2024, original scientific article Abstract: 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. Keywords: cross laminated timber, CLT, beam, shear testing, shear capacity, design methods Published in DiRROS: 15.04.2024; Views: 399; Downloads: 204
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1408. Poročilo : Makro in mikro analiza vzorcev lesa za identifikacijo (javor)Jožica Gričar, Gregor Skoberne, Peter Prislan, 2024, treatise, preliminary study, study Keywords: gozdarstvo, les, makro analize, mikro analize, javor, identifikacija Published in DiRROS: 15.04.2024; Views: 398; Downloads: 95
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1409. Thermal characterisation of the cooling phase of post-flashover compartment firesAndrea Lucherini, Balša Jovanović, Jose L. Torero, Ruben Van Coile, Bart Merci, 2024, original scientific article Abstract: 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. Keywords: cooling phase, fire decay, fire dynamics, compartment fires, structural fire engineering, fire safety Published in DiRROS: 15.04.2024; Views: 390; Downloads: 183
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1410. An experimental apparatus for bench-scale fire testing using electrical heating padsAleksandra Seweryn, Andrea Lucherini, Jean-Marc Franssen, 2024, original scientific article Abstract: 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. Keywords: radiant panels, fire testing, heat transfer, heat flux, electrical heating pads, thermal boundary conditions Published in DiRROS: 15.04.2024; Views: 325; Downloads: 776
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