1. Experimental investigations of internal macro-scale convection in the loose-fill wood fiber insulation layer of a full-scale wall elementMartin Veit, Hicham Johra, Nikolaj Rask, Simon M. Roesgaard, Rasmus Lund Jensen, 2026, original scientific article Abstract: With increasing restrictions on the energy efficiency of buildings, thicker insulation layers are installed in new and refurbished buildings to reduce heat losses. Previous studies have indicated that internal macro-scale convection cells can occur in thick porous insulation layers, decreasing the thermal performance of the envelope component. The focus of previous studies has been on horizontal insulation layers, most often composed of glass wool. Therefore, there is a lack of empirical data for loose-fill insulation and, in particular, bio-based materials, which have the potential of being more sustainable than conventional ones. The present investigation of this paper looks at the possibility of internal macro-scale convection inside loose-fill wood fiber insulation in a full-scale vertical wall element, with the modified Rayleigh number in the current investigation being between 20 and 45 and exhibiting internal convection in all cases. The experimental results show good agreement in terms of heat flux and temperature distribution with numerical simulations where the macro-scale convection is modelled explicitly. It also indicates that internal macro-scale convection can be modelled with existing building physics simulation tools, such as COMSOL. Finally, the internal macro-scale convection increases the effective U-value by up to 90 % for the highest temperature difference in steady-state conditions. This effect appears to diminish under dynamic boundary conditions, with a calculated effective U-value being within the uncertainty of the steady-state case with the lowest temperature difference, indicating that it might be less influential under real conditions.
Keywords: thermal performance, internal convection, performance gap, insulation materials
Published in DiRROS: 17.11.2025; Views: 37; Downloads: 14
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2. Temperature performance and rutting prediction of steel slag asphalt mixturesHongwen Du, Qinghao Han, Yunhao Wu, Linhua Ma, Minda Ren, 2025, original scientific article Keywords: road engineering, performance prediction, steel slag–rubber powder-modified asphalt mixture, optimization algorithms
Published in DiRROS: 03.10.2025; Views: 223; Downloads: 91
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4. Relationship between job characteristics and music performance anxiety in collaborative pianists working in Slovenian music schoolsKatarina Babnik, Žan Lep, Katarina Habe, 2025, original scientific article Abstract: Introduction: Music performance anxiety (MPA) is a significant challenge for amateur and professional musicians, as well as music students. Systematic literature reviews highlight a lack of research on the role of contextual variables in MPA. This study contributes to existing knowledge by examining how job characteristics, particularly job demands and job resources, influence MPA among collaborative pianists. Method: A cross-sectional quantitative study was conducted on 94 collaborative pianists (24% of the population) working at all three levels of the Slovenian music education system. Data were collected through an online survey, including demographic characteristics, objective workload measures, and perceived job characteristics scales (cognitive job demands, emotional demands, job influence, role clarity, role conflict, and organizational justice), along with an adapted MPA scale. Confirmatory factor analysis and internal consistency analysis were conducted for each scale, followed by correlation analysis and a multiple linear regression model to predict MPA. Results: The study tested six hypotheses, with mixed support for the proposed relationships. The regression model explained 50% (F = 5.11; df1 = 10, df2 = 51, p < 0.001) of the variance in MPA, with perceived emotional demands (β = 0. 50; t = 3.57; p < 0.001) and role conflict (β = 0.38; t = 2.65; p = 0.011) playing significant roles in predicting MPA. Discussion and conclusions: The findings enhance the understanding of MPA in the job context and have practical implications for music school management. Future research should explore the interaction between job characteristics and individual psychological resources across diverse professional and cultural contexts with representative samples.
Keywords: job demands, job resources, performance anxiety, music education, accompanists
Published in DiRROS: 29.09.2025; Views: 180; Downloads: 70
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7. Municipal solid waste incineration (MSWI) bottom ash-blended cementitious materials : performance, challenges, and potential solutionsBoyu Chen, Priyadharshini Perumal, Chen Liu, Yun Chen, Cheng Chang, Majda Pavlin, Davor Kvočka, Vilma Ducman, Tero Luukkonen, Mirja Illikainen, Guang Ye, 2025, review article Abstract: The recycling of municipal solid waste incineration (MSWI) bottom ash as a supplementary cementitious material (SCM) has attracted global attention, driven by the increasing availability of this by-product and the demand for sustainable SCMs to lower CO2 emissions from cement production. Currently, the widespread use of MSWI bottom ash in the cement industry is hindered by the lack of guidelines to regulate material composition, optimize pretreatment processes, and specify mix design requirements. This review compiles and analyzes literature data on mix design, microstructural evolution, fresh properties, mechanical properties, durability, leaching risks, and environmental impacts of MSWI bottom ash-blended cement pastes, mortars, and concretes. The analysis aims to assess the influence of the pretreatment and physicochemical properties of bottom ash on the microstructure and performance of blended cementitious materials. The Ash Impact Strength Index (AISI) is introduced to quantify the effects of various factors on compressive strength, enabling direct comparison across different studies. Based on the statistical analysis of the 28-day AISI, the key quality requirements for MSWI bottom ash as an SCM are proposed, along with the optimal mix design. This work provides valuable insights and practical guidance to support the integration of bottom ash into the cement industry.
Keywords: ash, ash-blended cementitious materials, performance
Published in DiRROS: 29.08.2025; Views: 340; Downloads: 237
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10. Influence of Building Envelope Modeling Parameters on Energy Simulation ResultsSimon Muhič, Dimitrije Manić, Ante Čikić, Mirko Komatina, 2025, original scientific article Abstract: This study investigates the influence of input values for building energy model parameters on simulation results, with the aim of improving the reliability and sustainability of energy performance assessments. Dynamic simulations were conducted in TRNSYS for three theoretical multi-residential buildings, varying parameters such as referent model dimensions, infiltration rates, envelope thermophysical properties, and interior thermal capacitance. The case study, based in Slovenia, demonstrates that glazing-related parameters, particularly the solar heat gain coefficient (g-value), exert the most significant influence—reducing the g-value from 0.62 to 0.22 decreased simulated heating (qH,nd) and cooling (qC,nd) demands by 25% and 95%, respectively. In contrast, referent dimensions for modeled floor area proved least influential. For Building III (BSF = 0.36), dimensional variations altered results by less than ±1%, whereas, for Building I (BSF = 0.62), variations reached up to ±20%. In general, lower shape factors yield more robust energy models that are less sensitive to input deviations. These findings are critical for promoting resource-efficient simulation practices and ensuring that energy modeling contributes effectively to sustainable building design. Understanding which inputs warrant detailed attention supports more targeted and meaningful simulation workflows, enabling more accurate and impactful strategies for building energy efficiency and long-term environmental performance.
Keywords: building energy modeling, dynamic simulation, TRNSYS, envelope modeling parameters, building energy performance
Published in DiRROS: 19.06.2025; Views: 424; Downloads: 282
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