1. Quantitative aspects of ToF-SIMS analysis of metals and alloys in a UHV, O2 and H2 atmosphereJernej Ekar, Saša Kos, Janez Kovač, 2024, original scientific article Abstract: Although secondary ion mass spectrometry (SIMS) is a versatile method used in the fields of surface analysis, depth profiling and elemental and molecular mapping, it also lacks quantification capabilities. The main reason for this is the matrix effect, which influences the ionization yield of secondary ions with respect to the substrate from which the analyzed compounds originate. There are several approaches to reduce the matrix effect, and gas flooding is one of the easiest methods to apply. In this work, we have investigated the possibilities of the ToF-SIMS method for the quantification of selected metals and alloys containing these metals in different ratios by reducing the matrix effect in the presence of different atmospheres. The measurements were performed in the ultra-high vacuum (UHV) environment, H2 and O2 atmospheres. H2 flooding shows the most significant improvements compared to the UHV analysis, while O2 is also promising but has some limitations. Improvements are most evident for the transition metals Ti, Cr, Fe, Co and Ni employed in our study, while the p-block elements such as Al and Si do not change so extensively. The deviations from the true atomic ratios of selected transition metals in different alloys reach a maximum of only 46 % when analyzed in the H2 atmosphere. In contrast, these values are 66 and 228 % for the O2 atmosphere and UHV environment, respectively. Our results suggest that gas adsorption and consequent formation of a new matrix on the surface, especially in the case of hydrogen, reduces the differences between the different chemical environments and electronic structures of the surface. In this way, the quantitative aspects of the SIMS method can be improved.
Keywords: ToF-SIMS quantification, H2 and O2 gas flooding, matrix effect reduction, cluster secondary ions
Published in DiRROS: 15.05.2024; Views: 25; Downloads: 11
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2. Coastal flood risk assessment : an approach to accurately map flooding through national registry-reported eventsErik Kralj, Peter Kumer, Cécil J. W. Meulenberg, 2023, original scientific article Keywords: sea flood prediction, flooding maps, climate change resilience, natural disaster registry, coastal inundation, flood-prone areas
Published in DiRROS: 08.12.2023; Views: 275; Downloads: 120
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3. ToF-SIMS depth profiling of metal, metal oxide, and alloy multilayers in atmospheres of ▫$H_2$▫, ▫$C_2H_2$▫, CO, and ▫$O_2$▫Jernej Ekar, Peter Panjan, Sandra Drev, Janez Kovač, 2022, original scientific article Keywords: Ions, Layers, Mass spectrometry, Metals, Oxides, SIMS depth profiling H2 C2H2 CO and O2 atmosphere gas flooding cluster secondary ions matrix effect
Published in DiRROS: 18.10.2023; Views: 353; Downloads: 155
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4. Flood vulnerability study of a roadway bridge subjected to hydrodynamic actions, local scour and wood debris accumulationMirko Kosič, Andrej Anžlin, Valentina Bau', 2022, original scientific article Abstract: The increased occurrence and intensity of flooding events have represented a real threat to bridge reliability and end-user safety. As flood vulnerability assessment is a valuable tool for enhancing the resilience of bridges to climate change, it is of interest to push the development of such methods. To this end, a computationally efficient methodology to assess the flood vulnerability of a bridge was developed and implemented in a case study. A particular focus was devoted to modelling wood debris loads on the bridge pier, for which two different approaches were implemented. The first is a standards-based approach, whereas the second is based on up-to-date research data. The results indicate that the second approach is less conservative as it leads up to a 40% higher exceedance probability for the considered limit states. The interaction between wood debris loads and local scour was also examined and proved to have a relevant impact on the vulnerability of the bridge. These results highlight the shortcomings of the existing standards in providing accurate results. It is perceived that not only will the new quantitative tool be valuable in ensuring optimal bridge design, but it will also be beneficial for assessing bridge risk mitigation measures.
Keywords: flooding, vulnerability, wood debris, local scour, hydrodynamic load, stochastic approach, bridges, open access
Published in DiRROS: 31.05.2023; Views: 362; Downloads: 201
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5. Analysis of the response of a roadway bridge under extreme flooding-related events: Scour and debris-loadingMirko Kosič, Luke J. Prendergast, Andrej Anžlin, 2023, original scientific article Abstract: Hydraulic actions on bridges are a leading cause of failure, especially due to the occurrence of scour erosion. Due to climate change, flooding and scour risks are exacerbating for bridges worldwide, leading to a significant stress burden on asset management agencies. Assessing structures for scour has received significant attention in recent years, however, there are few studies which investigate the influence of scour on the components of a bridge to understand how various elements interact. Moreover, the presence of debris loading, which can occur due to flooding causing debris to become lodged at structures, has not received significant attention. Debris can worsen scour conditions and increase hydraulic loading on a bridge. In this paper, an analysis of the response of various components of a roadway bridge when exposed to extreme flooding is conducted. The influence of scour and debris on hydraulic loading, internal forces, modal periods, and utilization ratios of various bridge components is ascertained. A numerical model is developed using OpenSees employing two different methods to model the soil-structure interaction. Results for several flooding scenarios show how the various bridge elements are influenced by variations in water height and velocity, scour depth, and presence of debris.
Keywords: local scour, wood debris, flooding, resilience, soil-structure interaction, bridges, open access
Published in DiRROS: 29.05.2023; Views: 339; Downloads: 259
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