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21.
Causes and consequences of large-scale windthrow on the development of fir-beech forests in the Dinaric mountains
Matjaž Čater, Ajša Alagić, Mitja Ferlan, Jernej Jevšenak, Aleksander Marinšek, 2023, izvirni znanstveni članek

Povzetek: We investigated several aspects of windthrow that are relevant to our understanding and management of forest ecosystems. As an example, we used an extreme event in December 2017, when the strongest storm in recent history occurred in the Slovenian Dinaric High Karst. We examined influential factors such as soil properties, wind speed, precipitation and ecological consequences for the affected forests. Soil properties were measured around standing and fallen silver fir trees at all three research sites. Tree species composition in the regeneration was observed on plots with chemical and acoustic ungulate deterrents and on control plots without deterrents. Economic estimates of yield loss due to damage were calculated at the national level. A model of the potential threat from windthrow was also developed based on data collected from windthrow events and meteorological data over the past 20 years. Our results indicate that soil depth and mineral fraction depth were similar at sites with and without damaged trees and were not the determining factors for tree toppling. Plots with acoustic deterrents showed the most effective regeneration development, the least decline in silver fir and the greatest increase in noble hardwood seedlings, while plots with chemical deterrents showed the least browsing damage. The estimated economic loss of €16.1 million is 6.6% less than the harvest under normal conditions. The economic loss was relatively low due to the nature of the storm, with the predominant type of damage being uprooted trees with no damaged trunks. The windthrow hazard model revealed that a large number of consecutive events with strong winds in each section weakened the stand, which was subsequently knocked down during the next extreme wind and rainfall event.
Ključne besede: natural forest regeneration, windthrow, economic loss, browsing, ungulate deterrents, forest soil properties, potential threat model
Objavljeno v DiRROS: 27.06.2023; Ogledov: 1060; Prenosov: 505
.pdf Celotno besedilo (2,26 MB)
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22.
Organoidi glioblastoma razkrivajo odpornost na standardno terapijo
Bernarda Majc, Anamarija Habič, Marta Malavolta, Aleksander Sadikov, Andrej Porčnik, Jernej Mlakar, Tamara Lah Turnšek, Barbara Breznik, Metka Novak, 2023, objavljeni povzetek znanstvenega prispevka na konferenci

Ključne besede: glioblastom, organoidi, standardna terapija, model ex vivo, biologija raka
Objavljeno v DiRROS: 16.06.2023; Ogledov: 340; Prenosov: 116
.pdf Celotno besedilo (345,36 KB)
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23.
Model updating concept using bridge Weigh-in-Motion data
Doron Hekič, Andrej Anžlin, Maja Kreslin, Aleš Žnidarič, Peter Češarek, 2023, izvirni znanstveni članek

Povzetek: Finite element (FE) model updating of bridges is based on the measured modal parameters and less frequently on the measured structural response under a known load. Until recently, the FE model updating did not consider strain measurements from sensors installed for weighing vehicles with bridge weigh-in-motion (B-WIM) systems. A 50-year-old multi-span concrete highway viaduct, renovated between 2017 and 2019, was equipped with continuous monitoring system with over 200 sensors, and a B-WIM system. In the most heavily instrumented span, the maximum measured longitudinal strains induced by the full-speed calibration vehicle passages were compared with the modelled strains. Based on the sensitivity study results, three variables that affected its overall stiffness were updated: Young’s modulus adjustment factor of all structural elements, and two anchorage reduction factors that considered the interaction between the superstructure and non-structural elements. The analysis confirmed the importance of the initial manual FE model updating to correctly reflect the non-structural elements during the automatic nonlinear optimisation. It also demonstrated a successful use of pseudo-static B-WIM loading data during the model updating process and the potential to extend the proposed approach to using random B-WIM-weighed vehicles for FE model updating and long-term monitoring of structural parameters and load-dependent phenomena.
Ključne besede: monitoring, bridge, viaduct, bridge weigh-in-motion (B-WIM), structural health monitoring (SHM), finite element (FE), calibration, model updating
Objavljeno v DiRROS: 29.05.2023; Ogledov: 374; Prenosov: 196
.pdf Celotno besedilo (26,28 MB)
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24.
Development of groundwater flow models for the integrated management of the alluvial aquifer systems of Dravsko polje and Ptujsko polje, Slovenia
Ada Vengust, Anja Koroša, Janko Urbanc, Nina Mali, 2023, izvirni znanstveni članek

Povzetek: With increasing exploitation of groundwater resources and implementation of various activities in their recharge areas, it is vital to conduct a comprehensive assessment of aquifers to ensure their conservation and sustainable management. In the present study, we used a comprehensive approach to conceptualise and identify the functioning of two connected aquifer systems in north-eastern Slovenia: the Quaternary porous aquifers Dravsko polje and Ptujsko polje. The study presents the conceptual models of both aquifers and their interconnectedness using separate mathematical-numerical models with the aim of ensuring an integrated management of these alluvial aquifer systems. It also highlights the importance of understanding connections between such systems for simulating groundwater flow and transport of different contaminants.
Ključne besede: hydrogeological model, Modflow model, aquifer geometry, aquifer recharge, modelling
Objavljeno v DiRROS: 27.03.2023; Ogledov: 417; Prenosov: 151
.pdf Celotno besedilo (5,58 MB)

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Evaluation of thermal conductivity estimation models with laboratory-measured thermal conductivities of sediments
Simona Adrinek, Rao Martand Singh, Mitja Janža, Mateusz Żeruń, Grzegorz Ryżyński, 2022, izvirni znanstveni članek

Povzetek: Thermal conductivity is one of the key parameters for estimating low-temperature geothermal potential. In addition to field techniques, it can be determined based on physical parameters of the sediment measured in the laboratory. Following the methodology for cohesive and non-cohesive sample preparation, laboratory measurements were carried out on 30 samples of sediments. Density, porosity and water content of samples were measured and used in thermal conductivity estimation models (TCEM). The bulk thermal conductivity (λb) calculated with six TCEMs was compared with the measured λb to evaluate the predictive capacity of the analytical methods used. The results show that the empirical TCEMs are suitable to predict the λb of the analysed sediment types, with the standard deviation of the residuals (RMSE) ranging from 0.11 to 0.35 Wm−1 K−1. To improve the fit, this study provides a new modified parameterisation of two empirical TCEMs (Kersten and Côté&Konrad model) and, therefore, suggests the most suitable TCEMs for specific sample conditions. The RMSE ranges from 0.11 to 0.29 Wm−1 K−1. Mixing TCEM showed an RMSE of up to 2.00 Wm−1 K−1, meaning they are not suitable for predicting sediment λb. The study provides an insight into the analytical determination of thermal conductivity based on the physical properties of sediments. The results can help to estimate the low-temperature geothermal potential more quickly and easily and promote the sustainable use of this renewable energy source, which has applications in environmental and engineering science.
Ključne besede: thermal conductivity, non-cohesive sediment, cohesive sediment, estimation model
Objavljeno v DiRROS: 25.08.2022; Ogledov: 525; Prenosov: 236
.pdf Celotno besedilo (2,61 MB)
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29.
Modelling seasonal dynamics of secondary growth in R
Jernej Jevšenak, Jožica Gričar, Sergio Rossi, Peter Prislan, 2022, izvirni znanstveni članek

Povzetek: The monitoring of seasonal radial growth of woody plants addresses the ultimate question of when, how and why trees grow. Assessing the growth dynamics is important to quantify the effect of environmental drivers and understand how woody species will deal with the ongoing climatic changes. One of the crucial steps in the analyses of seasonal radial growth is to model the dynamics of xylem and phloem formation based on increment measurements on samples taken at relatively short intervals during the growing season. The most common approach is the use of the Gompertz equation, while other approaches, such as general additive models (GAMs) and generalised linear models (GLMs), have also been tested in recent years. For the first time, we explored artificial neural networks with Bayesian regularisation algorithm (BRNNs) and show that this method is easy to use, resistant to overfitting, tends to yield s-shaped curves and is therefore suitable for deriving temporal dynamics of secondary tree growth. We propose two data processing algorithms that allow more flexible fits. The main result of our work is the XPSgrowth() function implemented in the radial Tree Growth (rTG) R package, that can be used to evaluate and compare three modelling approaches: BRNN, GAM and the Gompertz function. The newly developed function, tested on intra-seasonal xylem and phloem formation data, has potential applications in many ecological and environmental disciplines where growth is expressed as a function of time. Different approaches were evaluated in terms of prediction error, while fitted curves were visually compared to derive their main characteristics. Our results suggest that there is no single best fitting method, therefore we recommend testing different fitting methods and selection of the optimal one.
Ključne besede: artificial neural networks, cambium, generalized additive model, Gompertz function, growing season, intra-annual time series
Objavljeno v DiRROS: 21.07.2022; Ogledov: 464; Prenosov: 313
.pdf Celotno besedilo (1,26 MB)
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30.
Synoptic risk assessment of groundwater contamination from landfills
Sonja Cerar, Luka Serianz, Katja Koren, Joerg Prestor, Nina Mali, 2022, izvirni znanstveni članek

Povzetek: Waste management in Europe has improved in recent years, reducing the amount of waste disposed at landfills. However, there are still many landfills in the countries. It is well known that landfills that do not have measures in place to control leachate entering groundwater can contaminate groundwater long after the landfill is closed. Collecting monitoring results from all landfills allows permitting and management agencies to improve action plans. This relies on a synoptic risk assessment that allows prioritization and milestones to be set for required actions. The developed method of synoptic risk assessment is based on a conceptual model of the landfill and the results of chemical groundwater monitoring tested at 69 landfills in Slovenia. The study confirms that most landfills have a direct or indirect impact on groundwater quality. All landfills were classified into three priority classes on the basis of the synoptic risk assessment. The results show that a total of 24 landfills have a clearly pronounced impact on groundwater. A total of 31 landfills have a less pronounced impact due to the favorable natural attenuation capacity of the soil or the technically appropriate design of the landfill itself. A total of 14 landfills have a less pronounced or negligible impact on groundwater.
Ključne besede: conceptual model, synoptic risk assessment, landfill, groundwater, chemical analysis
Objavljeno v DiRROS: 19.07.2022; Ogledov: 528; Prenosov: 280
.pdf Celotno besedilo (3,09 MB)
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