1731. More losses than gains? : Distribution models predict species-specific shifts in climatic suitability for European beech forest herbs under climate changeJanez Kermavnar, Lado Kutnar, Aleksander Marinšek, 2023, original scientific article Abstract: Introduction: Herbaceous plant species constitute an essential element of the flora of European beech (Fagus sylvatica) forests. There is increasing evidence that rapidly changing climate is likely to modify the spatial distribution of plant species. However, we lack understanding of the impact that climate change might have on beech forest herbs across the European continent. We investigated the possible effects of predicted increasing rates of global warming and altered precipitation regimes on 71 forest herbs closely associated with beech forests, but with varying biogeographic and climatic niche attributes. Methods: By using a total of 394,502 occurrence records and an ensemble of species distribution models (SDMs), we quantified the potential current distribution and future (2061-2080) range shifts in climatic suitability (expressed as occurrence probability, OP) according to two climate change scenarios (moderate SSP2-4.5 and severe SSP5-8.5). Results: Overall, precipitation of the warmest quarter and temperature seasonality were the most influential predictors in shaping current distribution patterns. For SSP5-8.5 scenario, all studied species experienced significant reductions (52.9% on average) in the total size of highly suitable areas (OP >0.75). However, the magnitude and directions of changes in the climatic suitability were highly species-specific; few species might even increase OP in the future, particularly in case of SSP2-4.5 scenario. The SDMs revealed the most substantial decline of climatic suitability at the trailing edges in southern Europe. We found that climatic suitability is predicted to show unidirectional northward shift and to move toward higher elevations. The gain/loss ratio was generally higher for narrow-ranged species compared to widespread taxa. Discussion: Our findings are contextualized with regards to potential confounding factors (dispersal limitation, microclimatic buffering) that may mitigate or accelerate climate change impacts. Given the low long-distance migration ability, many beech forest herbs are unlikely to track the velocity with which macroclimatic isotherms are moving toward higher latitudes, making this species group particularly vulnerable to climate change.
Keywords: species distribution modelling, global warming, range shift, climatic niche, biogeography, Europe
Published in DiRROS: 29.11.2023; Views: 385; Downloads: 200
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1732. 1. Šola maligne utesnitve hrbtenjače : [strokovno srečanje]2023, not set Abstract: Izidi zdravljenja maligne utesnitve hrbtenjače (MUH) v Sloveniji trenutno niso najboljši. Obravnava bolnikov je kompleksna, multidisciplinarna in večnivojska. Takoj ko bolnik zazna znake MUH, mora stanje prepoznati zdravnik družinske medicine, hitro ukrepati ter ga napotiti na nevrološki pregled oziroma k lečečemu onkologu. Namen 1. Šole maligne utesnitve hrbtenjače je, da se zdravniki, ki sodelujemo pri prepoznavi in zdravljenju MUH pogovorimo o trenutnem stanju obravnave in vseh dilemah, ki jih imamo.
Keywords: maligna utesnitev
Published in DiRROS: 29.11.2023; Views: 373; Downloads: 187
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1733. Experimental investigation of the axial strength of glued-in rods in cross laminated timberBoris Azinović, Erik Serrano, Miha Kramar, Tomaž Pazlar, 2018, original scientific article Abstract: This paper presents results from an experimental assessment of glued-in rods in cross laminated timber (CLT). For the purposes of the study more than 60 pull-pull tests were performed, where the specimens varied in terms of bonded-in length (from 80 to 400 mm), rod diameter (16-24 mm) and rod-to-grain angle (parallel and perpendicular). Several different failure modes that are not common for other applications of glued-in rods (e.g., a failure between CLT layers) were obtained for the analysed CLT specimens. It was found that these failure mechanisms can substantially influence the obtained ultimate tension loads. At the end, the experimental results were compared with empirical and semi-empirical equations for estimating the pull-out strength of glued-in rods in structural timber and glulam. The comparison showed that most of the existing equations overestimate the ultimate tension loads for specimens with the rod parallel to the grain and underestimate the ultimate tension load for specimens with the rod perpendicular to the grain. The results vary because the possible CLT failure modes were not included in previous studies. Further studies are proposed to improve the equations for glued-in rods in CLT.
Keywords: glued-in rods, cross laminated timber (CLT), pull-pull experiment, glued-in length, rod-to-grain angle, failure mechanisms in CLT
Published in DiRROS: 29.11.2023; Views: 301; Downloads: 242
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1734. Structural health monitoring for performance assessment of bridges under flooding and seismic actionsLuke J. Prendergast, Maria P. Limongelli, Naida Ademovic, Andrej Anžlin, Gavin Kenneth, Mariano Zanini, 2018, original scientific article Abstract: Bridges can be subjected to damaging environmental actions due to flooding and seismic hazards. Flood actions that result in scour are a leading cause of bridge failure, while seismic actions that induce lateral forces may lead to high ductility demand that exceeds pier capacity. When combined, seismic actions and scour can lead to effects that depend on the governing scour condition affecting a bridge. Loss of stiffness under scour can reduce the ductility capacity of a bridge but can also lead to an increase in flexibility that may reduce seismic inertial forces. Conversely, increased flexibility can lead to deck collapse due to support loss, so there exists some uncertainty about the combined effect of both phenomena. A necessary step towards the performance assessment of bridges under flooding and seismic actions is to calibrate numerical models that can reproduce structural responses under different actions. A further step is verifying the achievement of performance goals defined by codes. Structural health monitoring (SHM) techniques allow the computation of performance parameters that are useful for calibrating numerical models and performing direct checks of performance goal compliance. In this paper, various strategies employed to monitor bridge health against scour and seismic actions are discussed, with a particular focus on vibration-based damage identification methods.
Keywords: scour, seismic, damage, hazard, vibration-based methods
Published in DiRROS: 29.11.2023; Views: 335; Downloads: 173
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1735. Condition assessment of roadway bridges: from performance parameters to performance goalsMaria P. Limongelli, Eleni Chatzi, Andrej Anžlin, 2018, original scientific article Abstract: Deterioration of bridges due to ageing and higher demands, induced by increased traffic load, require the development of effective maintenance policies and intervention strategies. Such concern should be aimed at ensuring the required levels of safety, while optimally managing the limited economic resources. This approach requires a transversal advance; from the element level, through the system level, all the way to the network level. At the same time intervention prioritisation based on the importance of the system (bridge) inside the network (e.g. highway), or of the single structural element inside the bridge is dependent. The first step in bridge condition assessment is the verification of safety and reliability requirements that is carried out using the traditional prescriptive (deterministic) approach or the current performance-based (probabilistic) approach. A critical issue for efficient management of infrastructures lies in the available knowledge on condition and performance of bridge asset. This information is obtained using a collection of significant Performance Parameters at one or more of the three levels (element, system, and network). Traditional techniques for estimation of Performance Parameters rely on already established visual inspection. However, a more reliable description of the system performance is obtained through Non-Destructive Testing and Structural Health Monitoring. Condition assessment essentially pertains to the check of compliance with Performance Goals and requires the definition and computation of Performance Indicators. They are calculated directly from Performance Parameters or from physical models calibrated using the Performance Parameters collected on the structure. Paper overviews the steps to bridge condition assessment regarding safety and reliability.
Keywords: bridge, reliability, safety, condition assessment, performance goals, performance parameters
Published in DiRROS: 29.11.2023; Views: 319; Downloads: 163
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1736. Cost-benefit analysis of fire protection in buildings : application of a present net value approachThomas Gernay, Shuna Ni, David Unobe, Andrea Lucherini, Ranjit Kumar Chaudhary, Ruben Van Coile, 2023, original scientific article Abstract: In fire safety engineering, cost–benefit analysis provides a systematic method to assess whether the projected benefits from a fire safety measure outweigh its costs. However, there remains a wide discrepancy between methods used in the field for cost–benefit analysis, as well as a lack of quantitative data on the costs and economic impact of fire protection in buildings. In a recent research project, a reference methodology was proposed based on Present Net Value evaluation and on a combination of specialized construction database, fire statistics, and numerical modeling for estimation of the cost components. This paper presents the application of the methodology to four case studies. The case studies allow describing the methodology, the collection of data, fire statistics, and loss estimation, as well as illustrating how the methodology can support decision-making when multiple alternatives are compared. Under the assumptions adopted for the single-family house and the residential timber building case studies, it is found that for every 1\$, invested in sprinklers, \$1.06 is saved. This benefit–cost ratio increases with increasing valuation of indirect losses and statistical value of life. Sensitivity analyses are provided to explore the robustness of the investment recommendations. The results of evaluations, adapted from the presented case studies with project-specific inputs, can support decision making for policy makers, insurance companies, and individual building owners.
Keywords: fire safety, cost-benefit analysis, fire protection, fire statistics, sprinklers, compartmentation
Published in DiRROS: 29.11.2023; Views: 415; Downloads: 103
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1738. In situ consideration of resistance of bridge girder according to EC2 with AEMAna Brunčič, Andrej Štrukelj, Maja Kreslin, Andrej Anžlin, Aljoša Šajna, 2023, published scientific conference contribution Abstract: The paper presents a case study of a considerably cracked and degraded bridge in Slovenia: with the implementation of in-situ measurements under bending and shear and the use of a non-destructive acoustic emission technique. Despite the existing crack system, the latter was able to detect microstructural changes. These were characterised by low values of average frequency (AF), as well as lower values of the rise time-amplitude ratio (RA), and energy. A correlation between shear capacity and acoustic activity was observed. This promises to expand the use of AE in the process of assessing of the load-bearing capacity of existing concrete structures.
Keywords: shear resistance, shear crack, crack width, acoustic emission (AE) parameters, bridge girder, stiffness, elasticity, damage evaluation
Published in DiRROS: 28.11.2023; Views: 367; Downloads: 157
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1739. Pilot production of façade panels : variability of mix designMajda Pavlin, Barbara Horvat, Vilma Ducman, 2023, published scientific conference contribution Abstract: As part of the WOOL2LOOP project, the Slovenian National Building and Civil Engineering Institute (ZAG), in collaboration with Termit d.d. were responsible for the production of façade panels. An initial mix design was developed at ZAG, where alkali-activated façade panels were produced, primarily from stone wool waste, while production took place at Termit. The mix design was changed twice during the pilot production, before a final product with suitable durability was developed. A compressive strength of up to 60 MPa and bending strength of approximately 20 MPa was achieved. The mechanical properties, however, varied, due to the unevenly milled batches of the milled mineral wool. Milling on a larger scale is very challenging, and it is difficult to obtain consistent quality of the milled material. Once the correct curing process had been found, however, the panels produced showed good performance. Moreover, the results from leaching tests showed that the elevated concentrations of certain elements (Cr, As and Mo) did not exceed the legal limits for non- hazardous waste.
Keywords: waste mineral wool, alkali activated material, façade panels, pilot production, circular economy
Published in DiRROS: 28.11.2023; Views: 366; Downloads: 154
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1740. Microwave irradiation of alkali - activated metakaolin slurryBarbara Horvat, Branka Mušič, Majda Pavlin, Vilma Ducman, 2023, published scientific conference contribution Abstract: The building and civil engineering industry generates more than 40% of man-caused carbon emissions, consumes a lot of energy just to produce building materials, generates a large amount of waste through construction and demolition, and consumes a large amount of natural resources. One of the possible solutions is to use alkali-activated materials, which can use waste instead of raw materials and are produced at lower temperatures, with less energy consumption and in less time than traditional building products. All of this lowers the carbon footprint, which could be further reduced by the timely-short implementation of microwave irradiation in the early stages of alkali-activation synthesis. Therefore, metakaolin activated with Na-water glass in a theoretically optimal ratio was irradiated with microwaves of 2.45 GHz at powers of 100 W and 1000 W for 1 min, and compared to non-irradiated reference cured only at room conditions. Samples prepared at higher power, i.e., 1000 W, solidified completely and foamed. TG-DTA was performed on all samples in the early stages of curing, mechanical strengths were measured on 3 and 28-day- old samples, and leaching tests on aged samples.
Keywords: metakaolin, alkali activated material, alkali activated foams, microwave irradiation
Published in DiRROS: 28.11.2023; Views: 352; Downloads: 157
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