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Author Lu, Q.
Title Precipitation behavior and heat resistance properties of Al-Cu-Mg-Ag-(Si) alloy Type (down) Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume Issue Pages VIII, 212 p.
Keywords Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract With the rapid increase in the speed of new-generation aerospace vehicles, conventional heat-resistant aluminum alloys cannot meet the long-term service of the equipment. Therefore, the development of new high-strength heat-resistant aluminum alloys is of great strategic for the sustainable and high-quality development of industries. Al-Cu-Mg-Ag alloy is an age-hardenable heat-resistant aluminum alloy and has high strength and heat resistance. The addition of alloying elements such as Si and Sc to Al-Cu-Mg-Ag alloy introduces a competitive relationship among the σ-Al5Cu6Mg2, θ′-Al2Cu, and Ω phases. Therefore, a systematic investigation of precipitation behavior and heat resistance of Al-Cu-Mg-Ag-(Si) is essential for guiding the design of high-strength heat-resistant aluminum alloys. Combined characterization testing methods such as scanning electron microscopy, transmission electron microscopy, atom probe tomography, microhardness testing, and tensile testing with simulation calculation methods such as calculation of phase diagram, first-principles calculations, and Ab initio molecular dynamics, the effects of heat treatment processes and element content on the precipitation behavior, mechanical properties, and heat resistance of Al-Cu-Mg-Ag-(Si) alloys were systematically investigated. Furthermore, a multiple interface segregation structure was constructed at the θ′/Al interface, and a new Al-Cu-Mg-Ag-Si-Sc alloy with synergistically improved strength and heat resistance was developed. The main conclusions are as follows: (1) Based on the Kampmann-Wagner-Numerical theory, the relationship between the coarsening rate of the Ω phase and the aging process was analyzed, revealing for the first time that the critical size of Ω phase ( ) under thermal exposure temperature was the key factor determining the coarsening rate of Ω phase during long time thermal exposure heat treatment. After artificial ageing, when the size of Ω phase was smaller than the critical size , the dissolution of smaller Ω phase leaded to a rapid decrease in the number density of Ω phases, thereby reducing the heat resistance of the alloy. When the size of Ω phase was greater than or equal to the critical size , the coarsening rate of Ω phase was consistent, but a larger initial size would result in a larger final size after long-term thermal exposure. Therefore, the closer the size of Ω phase in the alloy is to the critical size under heat exposure temperature, the better the heat resistance of the alloy. (2) A concept of constructing a multiple interface segregation structure at the precipitate/matrix interface was proposed, and based on this concept, a multiple interface segregation structure containing the C/L-AlMgSiCu interfacial phase, newly discovered χ-AgMg interfacial phase, and Sc segregation layer was successfully constructed at the θ′/Al interface. The existence of the multiple interface segregation structure ensured that the designed Al-Cu-Mg-Ag-Si-Sc alloy maintains a yield strength of 400 MPa after thermal exposure at 200 C for 100 h, with a strength retention rate of 97%, creating a new record for the synergistic improvement of strength and heat resistance in aluminum alloys. In addition, combining transmission electron microscopy ex-situ/in-situ characterization with first-principles calculations, it is shown that the χ-AgMg interface phase will be destroyed due to the diffusion of the outer Ag layer during thermal exposure, and gradually dissolve into the matrix, but it can still delay the coarsening behavior of θ′-Al2Cu phase. (3) The criteria for determining whether Ω phase can precipitate are updated in Al-Cu-Mg-Ag-Si alloys with low Mg/Si ratio based on phase diagram thermodynamic calculations and multi-scale structural characterization. When W(Mg)/W(Si) > 1.4 and X(Ag)/X(Mgexcess) > 1, Ω phase can precipitate in Al-Cu-Mg-Ag-Si alloys, where X(Mgexcess) represents the atomic percentage of residual Mg elements after the formation of the AlMgSiCu quaternary precipitate phase C/L phase in the supersaturated solid solution, and the W(Mg) is the mass fraction of Mg in the supersaturated solid solution before artificial ageing. (4) The effects of alloy element content on precipitation behavior and heat resistance of Al-Cu-Mg-Ag-Si alloys were systematically analyzed. Critical conditions for the precipitation of σ-Al5Cu6Mg2 and Ω phase in Al-Cu-Mg-Ag-Si alloys are revealed. Based on calculation of phase diagram results, the conditions for precipitating σ-Al5Cu6Mg2 phase in the alloy are: ① W(Mg)/W(Si) > 1.8; ② W(Cu) > 2.7W(Mg) – 5W(Si). When W(Mg)/W(Si) < 1.8, the alloy is mainly precipitated with C/L/Q′-AlMgSiCu. When W(Cu) < 2.7W(Mg) – 5W(Si), the alloy will generate GPB zone. In addition, W(Ag)/W(Si) > 4 is the critical condition which the Ω phase can the main precipitates in Al-Cu-Mg-Ag-Si alloys. Furthermore, the correlation between precipitate types and heat resistance was summarized, showing that Al-Cu-Mg-Ag-(Si) alloys with Ω phase as the main strengthening phase are more suitable for the preparation of structures with short service time but high temperature, while Al-Cu-Mg-Ag-(Si) alloys with low Mg content and multiple segregation structures are more suitable for structures requiring long-term service at medium to high temperatures. This study, for the first time, combines calculation of phase diagram with multi-scale microstructure characterization, systematically unraveling the effects of element content on precipitation behavior, strength, and heat resistance of Al-Cu-Mg-Ag-(Si) alloys. In addition, a concept of constructing a multiple interface segregation structure at the precipitate/matrix interface was proposed to synergistically improve alloy strength and heat resistance. This work provides theoretical guidance for optimizing the composition and processing of Al-Cu-Mg-Ag-(Si) alloy and regulating the microstructure. Furthermore, it also offers new ideas and theoretical guidance for the development of novel high-strength heat-resistant alloys in other systems.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:206180 Serial 9167
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Author Manaigo, F.
Title Study of a gliding arc discharge for sustainable nitrogen fixation into NOx Type (down) Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume Issue Pages xxiv, 114 p.
Keywords Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract With the growth of the world population, the agricultural sector is required to meet an increasing demand for nutrients and currently relies on industrially produced fertilizers. Among them, nitrogen-based fertilizers are the most common choice and require N2 to be converted into more reactive molecules in a process called “nitrogen fixation”. This is mainly performed through the Haber-Bosch process, which, is not ideal since it requires large-scale facilities to be economical and is associated with a high energy cost and high CO2 emissions, resulting in an environmental impact that is pushing for the study of greener alternatives. Among these, plasma-based nitrogen fixation into NOx is promising, and gliding arc plasma, specifically, proved to be suitable for nitrogen fixation. This thesis aims to study plasma-based nitrogen fixation focusing on an atmospheric pressure gliding arc plasma on three different levels. On a fundamental level, an approach dealing with laser-based excitation of separate rotational lines was successfully developed. This method can be implemented on atmospheric discharges that produce rather high NOx densities and, thus, can impose essential restrictions for the use of “classical” laser-induced fluorescence methods. The approach is then implemented, providing a discussion on the two-dimensional distributions of both the gas temperature and the NO ground state density. A clear correlation between these quantities is found and the effects of both the gas temperature and the plasma power on NO and NO2 concentrations are discussed, revealing how the NO oxidation is already significant in the plasma afterglow region and how the gas flow rate is a crucial parameter affecting the temperature gradients. >From a technological level, the conventional approach of introducing external resistors to stabilize the arc is challenged by studying both its performance and its stability replacing the external resistor with an inductor. We conclude that similar stabilization results can be obtained while significantly lowering the overall energy cost, which decreased from up to a maximum of 7.9 MJ/mol N to 3 MJ/mol N. Finally, we study whether a small-scale fertilizer production facility based on a gliding arc plasma can be a local competitive alternative. This is done by proposing a comparative model to understand how capital, operative expenditures and transport costs affect the production costs. The model highlights how, with the current best available technology, plasma-based nitrogen fixation, while being an interesting alternative for NOx synthesis, still requires a more efficient use of H2 for direct NH3 production.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:205259 Serial 9175
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Author Van Hoecke, L.
Title CFD-Assisted design of fluidized reactors for H2 release from LOHC Type (down) Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume Issue Pages XXXIII, 181 p.
Keywords Doctoral thesis; Engineering sciences. Technology
Abstract Hydrogen (H2) is expected to become a key molecule in the transition towards a society running on renewable energy. It can be used to store excess renewable energy at peak production moments and release this energy at a later stage when renewable energy production is less. However, storing H2 is challenging due to the low density of this gas. As a solution, Liquid Organic Hydrogen Carriers or LOHC molecules have been proposed in the passed to increase volumetric energy density of H2. LOHC are a class of molecules that have storage sites available, to which the H2 gas can be chemically bounded. The LOHC molecule under investigation was dibenzyltoluene (DBT), which is an oil like liquid, that is easy to transport and poses little fire or explosion risks. To release the H2 from the DBT carrier, via a so-called dehydrogenation reaction, efficient mass and heat transfer is required during the process, since a large volume increase is expected from H2 release and the reaction is endothermic, i.e., a self – cooling process that takes place at temperatures around 300 C. The heat has to be supplied specifically to the active sites of catalyst particles that are present inside the reactor and which enable the dehydrogenation to proceed. For heat transfer limited processes fluidized bed reactors are often used, which is a type of reactor where the particle phase is being agitated by the fluid flow. The research proposed in this work, was to explore via computational fluid dynamics (CFD) simulations the possibilities and challenges of using fluidized bed reactors for the dehydrogenation of LOHC. The model selection required for CFD simulations of a three-phase system was investigated in this work, with a main emphasis on the drag model selection. The CFD modelling study was focused on the use of swirling fluidized bed reactors, since it was hypothesised that the swirling effect could also aid in increased removal of the gas phase from the reaction medium to increase the efficiency of the process. Ultimately, it was shown that the main challenges in the design of fluidized bed reactors will be to create uniform particle distribution inside the reactor. A new design for a dehydrogenation reactor is proposed based on the insights gained in this thesis.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-06-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:205645 Serial 9192
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Author Clavel, J.
Title Plant-mycorrhizal interactions and their role in plant invasions in mountains Type (down) Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume Issue Pages 182 p.
Keywords Doctoral thesis; Plant and Ecosystems (PLECO) – Ecology in a time of change
Abstract Non-native species invasions are one of the most impactful drivers of biodiversity and ecosystem services loss worldwide. One aspect of plant species invasion, which is only recently starting to be recognized as a determinant of invasion success, is the symbiosis between plant and mycorrhizal fungi. Here, I focus on anthropogenic disturbance in mountain ecosystems and its impact on plant communities and mycorrhizal fungi to answer how these communities are impacted by disturbance and whether non-native plants can benefit to establish and spread. To this end I used a combination of different approaches: 1) repeated surveys of plants and arbuscular mycorrhizal fungi along disturbed roadsides in the mountains of Norway, 2) combining a global dataset of native and non-native plants along mountain roads with a database associating plants with their mycorrhizal types, and 3) an in-situ experiment measuring non-native plant success and changes in fungal community following different types of disturbances. Through these methods, I could assess the effects of anthropogenic disturbance on mycorrhizal symbiosis and non-native plant species at multiple scales and resolutions. We found that road disturbance has a globally consistent effect on mycorrhizal types in mountain systems, as plants associated with arbuscular mycorrhizal (AM) fungi were more abundant following disturbance. Conversely, vegetation associated with either ectomycorrhizal (EcM) or ericoid mycorrhizal (ErM) fungi was less abundant in disturbed sites. In the regional study, AM fungi were most abundant and diverse in the roots of plant communities affected by road disturbance. Non-native plants were also restricted to these disturbed sites. The experimental results showed that physical disturbance and nutrient addition have negative effects on EcM fungi and positive effects on fungal pathogens, and facilitate non-native plant success. Our results show that anthropogenic disturbance does have an effect on mycorrhizal fungi that in turn impacts the distribution of plant species in disturbed mountain systems. The resulting shift in mycorrhizal fungi benefiting AM fungi and AM plant species could have implications for non-native plant invasions. Indeed, we know that non-native plants predominantly form associations with AM fungi. Therefore, anthropogenic disturbance can facilitate non-native plant success through disruption of the native fungal communities, and especially so in high elevation and cold climate regions which are naturally less dominated by AM plants. I believe this highlights the importance of mycorrhizal symbiosis in understanding plant invasions and emphasizes the importance of monitoring sources of anthropogenic disturbance in mountains to prevent future establishment of non-native plants.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:204154 Serial 9219
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Author Ramirez-Rojas, I.
Title Underground connections : the interplay between tropical rainforest trees and soil microbial communities Type (down) Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume Issue Pages 205 p.
Keywords Doctoral thesis; Plant and Ecosystems (PLECO) – Ecology in a time of change
Abstract Tropical rainforests host an exceptional biodiversity and play a fundamental role in the regulation of global climatic cycles. Soil fungi and bacteria are key players in the transformation and processing of nutrients in terrestrial ecosystems while having an essential role as tree mutualists or antagonists. Still, there are gaps in our understanding of the main variables driving soil microbes on these forests and it is unclear how future climate change scenarios may impact soil microbes and further affect the ecosystem. In this thesis, we first explored the drivers of the microbial community composition in two pristine forests in French Guiana by using amplicon DNA sequencing. The neighboring tree species were found to be a crucial factor influencing the fungal and bacterial community composition at our sites regardless of the season. Additionally, within the environmental factors explored, soil moisture, phosphorus (P) and nitrogen (N) availability were consistently the main soil properties controlling the composition of soil microbial communities. Secondly, as increased nutrient deposition due to anthropogenic activities are expected to affect tropical forests ecosystems N and P availability, a factorial N and P nutrient addition experiment in the same sites was used to assess the effects of changes in the soil nutrient stoichiometry on the soil microbial communities. These results showed that after 3 years of nutrient additions, the bacterial and fungal community composition was affected by both the N and P additions. Besides, the fungal community composition had a stronger response to the nutrient addition, especially when P was added. Moreover, when the nutrient addition effect was assessed in bacteria and fungi with different life strategies, we found different nutrient optima between them. Furthermore, to study the effect of the connection to an existing mycorrhizal mycelium on tree seedlings, I established a mycelium exclusion experiment. Interestingly, we could not detect an effect of the mycorrhizal mycelium exclusion on the seedling N uptake, performance, or fungal community composition in roots after one year. All together this work provides a deeper understanding of the factors influencing the soil microbial communities on these lowland tropical forests, demonstrating that the tree community composition exerts a higher influence on the soil microbial community composition than previously expected. Moreover, our results show that the fungal and bacterial community composition and its relationship with trees in the vicinity is highly dependent on the ecosystem nutrient availability.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:204907 Serial 9237
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Author Li, L.
Title Untangling microbial community assembly in rainforest and grassland soils under increasing precipitation persistence Type (down) Doctoral thesis
Year 2023 Publication Abbreviated Journal
Volume Issue Pages 179 p.
Keywords Doctoral thesis; Integrated Molecular Plant Physiology Research (IMPRES); Plant and Ecosystems (PLECO) – Ecology in a time of change
Abstract Climate change is causing alterations in precipitation patterns, leading to adverse ecological consequences in many ecosystems. Recently, an increasingly persistent weather pattern has emerged, characterized by lengthening the duration of alternating dry and wet periods, which is more complex than exclusively drought or increasing precipitation. It is currently unclear how soil microbial communities respond to these new regimes in relation to their interactions with plants, especially in precipitation-sensitive ecosystems, such as tropical rainforests and grasslands. In this thesis, we explored responses of soil bacterial and fungal communities to increasing weather persistence in rainforests and grasslands, using high throughput sequencing technology. We firstly investigated the resistance and resilience of microbial communities to prolonged drought in a mature seasonal tropical rainforest which experiences unusually intensive dry seasons in the current century. Through excluding rainfall during and after the dry season, a simulated prolongation of the dry season by five months was compared to the control. Our results indicate that as rain exclusion progressed, the microbial communities increasingly diverged from the control, indicating a moderate resistance to prolonged drought. However, when the drought ceased, the composition and co-occurrence patterns of soil microbial communities immediately recovered to that in the control, implying a high resilience. To further investigate the ecological roles of soil microbial communities in response to increasing weather persistence, we set up grassland mesocosm experiments. In these experiments, precipitation frequency was adjusted along a series, ranging from 1 to 60 consecutive days alternating of dry and wet periods, while keeping the total precipitation constant. Our results show that microbial community assembly tended to be more stochastic processes at intermediate persistence of dry and wet alternations while more deterministic processes dominated at low and high persistence within 120 days regime exposure. Moreover, more persistent precipitation reduced the fungal diversity and network connectivity but barely impacted that of bacterial communities. The prior experiences of persistent weather events for one year caused legacy effects. The soil microbial legacy induced by soil microbial communities subjected to prior persistent weather events was more enduring in subsequent fungal communities than bacterial communities, likely due to slower growth of fungi compared to bacteria. However, a minor effect of soil microbial legacy  was observed on plant performance. In addition, we kept the grassland mesocosm experiment for two growing seasons. The effects of precipitation persistence on soil microbial communities increased in the second year. The dissimilarities of microbial communities between the first and second year were less with more persistent precipitation, potentially resulting in more vulnerable microbial communities, due to some taxa disappearing and a reduction in functional redundancy under more persistent weather. To conclude, our findings provide a comprehensive theoretical understanding of soil microbial communities in response to the current and future climate change, drawing from both natural and experimental systems. It helps in predicting and managing the impacts of future climate change on ecosystems mediated by microbial communities. Additionally, the findings of microbe-mediated legacy effects on grassland ecosystems can provide practical guidance for their application in agriculture, specifically for using an inoculum to mitigate the impacts of climate change.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:198498 Serial 9240
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Author Montiel, F.N.
Title Voltage against illicit drug trafficking : capabilities of electrochemical fingerprinting to detect illicit drugs Type (down) Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume Issue Pages 256 p.
Keywords Doctoral thesis; Pharmacology. Therapy; Engineering sciences. Technology; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:204707 Serial 9243
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Author Gao, C.
Title Exploring electron ptychography for low dose imaging Type (down) Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume Issue Pages xii, 146 p.
Keywords Doctoral thesis; Electron microscopy for materials research (EMAT)
Abstract Transmission electron microscopy is an important technique in the exploration of materials’ structures. This is especially true since the development of electron optical aberration correctors greatly facilitated atomic resolution imaging. We are currently experiencing an ongoing revolution in electron microscopy with the widespread adoption of direct electron detectors. Scientists have reported a lot of key scientific findings facilitated by direct electron detectors. One particular research domain is electron ptychography, which holds promise for unraveling the intricate structures of highly beam-sensitive materials like bio samples and achieving super-resolution without the limitation of aperture in the condenser lens system. Nevertheless, challenges persist both in experimental setups and algorithmic processes. Issues such as the comparatively sluggish scanning speed of cameras and contrast reversals of the reconstructed phase for relatively thick specimens, disrupting phase or weak phase approximations, remain noteworthy limitations. This thesis addresses these challenges by the event-driven Timepix3 detector, presenting a viable solution to the speed bottleneck. Moreover, innovative approaches for applying electron ptychography to relatively thick samples, employing a middle focusing strategy, are proposed. This research aims to push the boundaries of electron microscopy, offering solutions to existing limitations and advancing the field towards more efficient and accurate imaging techniques.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-07-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:206777 Serial 9289
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Author Chinnabathini, V.C.
Title Gas phase bimetallic nanoclusters-modified TiO2 supports as efficient photo(electro)catalysts for self-cleaning surfaces and water splitting Type (down) Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume Issue Pages xviii, 149 p.
Keywords Doctoral thesis; Antwerp engineering, PhotoElectroChemistry & Sensing (A-PECS)
Abstract In the context of global challenges such as climate change and environmental pollution, photocatalysis evolved as one of the promising strategies for sustainable energy conversion and pollutant degradation. In this thesis, photocatalysis using gas phase deposited bimetallic nanoclusters (BNCs) on TiO2 supports is studied in the context of self-cleaning surfaces and photoelectrochemical (PEC) water splitting applications. Thanks to their plasmonic properties, BNCs made of coinage metals can serve as efficient cocatalysts for the degradation of organic pollutants and surface contaminants under light irradiation. They also hold great promise for PEC water splitting, a promising pathway for renewable hydrogen production, which can be used in hydrogen fuel cells or for the environmentally friendly production of fuels in, for example, CO2 hydrogenation processes. The small size and high surface-to-volume ratio of plasmonic BNCs play pivotal roles in influencing the efficiency and selectivity of photocatalytic processes. BNCs have unique optical, physical, chemical, and structural properties distinctly different from their bulk and monometallic counterparts. These properties can be fine-tuned at the single particle level by their size, composition, and atomic arrangement, but also by interaction with other particles through the coverage and through interaction with the support. To design better photocatalysts it is crucial to carefully understand the BNCs’ characteristic properties, especially at the atomic level where synergies between different elements are sought. To achieve this objective, BNCs with well-defined sizes and compositions are deposited on TiO2 supports and we studied their structural properties and their influence on the photocatalytic activity. The general procedure followed in this thesis is the production and deposition of BNCs on TiO2 by the cluster beam deposition (CBD) technique, followed by structural and optical characterization to understand their tailored properties, and photocatalytic testing either for photodecomposition of organic molecules or PEC water splitting. In a first study, AuxAg1-x (x = 1, 0.9, 0.7, 0.5, 0.3, and 0) alloy BNCs with different compositions are synthesized in the gas phase and deposited from a molecular beam on TiO2 P25 supports. The photocatalytic self-cleaning activity of as-prepared samples is tested under UV and visible light towards stearic acid (SA) degradation. SA is a widely accepted model contaminant, which represents the group of organic fouling compounds that typically contaminates glass surfaces. A composition-dependent activity is observed with the Au0.3Ag0.7 nanocluster modified TiO2 exhibiting the highest photoactivity. Scanning transmission electron microscopy (STEM) measurements reveal that, for a mass loading corresponding to an equivalent of 4 atomic monolayers (MLs), the BNCs are uniformly distributed over the surface. The clusters have an average size of 3.5 ± 0.5 nm and are crystalline in nature. The atomic structure is characterized by X-ray absorption fine structure (XAFS) spectroscopy and their electronic structure by X-ray photoelectron spectroscopy (XPS). These measurements demonstrate a charge redistribution between the Ag and Au atoms when alloyed at the nanoscale. The effect of this charge redistribution is likely the stabilization of Ag against oxidation and directly affects the catalytic properties of the clusters. It is suggested that the highest photoactivity of 4 ML loaded Au0.3Ag0.7 under solar light results from a combination of four main possible contributing factors: (i) injection in TiO2 of excited carriers that are generated by the localized surface plasmon resonance (LSPR) effect of the BNCs in the visible light wavelength range which overlaps with the sun’s irradiance spectrum. (ii) a strong near-field enhancement that increases the photoabsorption by the TiO2 for photons that have enough energy to overcome the high bandgap, (iii) the optimized total metal loading of 4 ML leaves enough of the TiO2 surface accessible for light absorption, and finally (iv) an effective charge distribution between Au and Ag. This study demonstrates that CBD is an efficient approach for fabricating well-defined, tunable AuAg plasmon-based photocatalysts for self-cleaning applications, outperforming their monometallic counterparts as well as bimetallic alternatives obtained through colloidal methods. In a second study, titania nanotubes (TNTs) are modified with a series of AuxCu1-x (x = 1, 0.75, 0.5, 0.25, and 0) BNCs using the CBD technique. Based on the results of the first study, we opted again for a loading of 4 ML. TNTs are known for their high surface area, fast charge transfer, and corrosion resistance, while keeping the inherent strengths of traditional TiO2 materials. They prove to be promising photoanodes, enhancing photocurrent in PEC applications for water oxidation. In this work the TNTs are grown via anodic oxidation of a titanium metal foil. The crystalline anatase phase of the grown TNTs is confirmed by the X-ray diffraction technique (XRD), while transmission electron microscopy (TEM) provides information about the size and composition of the deposited BNCs. XAFS provides further structural information, while XPS measurements reveal charge redistribution between Au and Cu, which can aid in the enhancement of the PEC activity. Oxidation of as-prepared electrodes over the time results in structural changes with CuxO at the outer shell functioning as a protective layer, while the majority of the core is an alloy. The optical properties, studied through UV-Vis spectroscopy confirm the extended absorption range of the cluster-modified TNTs towards the visible region. The charge carrier recombination rate is derived from photoluminescence (PL) measurements. The as-prepared electrodes are tested photoelectrochemically for the generation of an anodic photocurrent using simulated sunlight. It is found that the AuxCu1-x (x = 1, 0.75, 0.5, 0.25 and 0) BNC modified TNTs show a remarkable enhancement in the anodic photocurrent relative to pristine TNTs, with Au0.25Cu0.75 exhibiting the highest photocurrent. This is due to the combination of many possible factors. Firstly, the charge redistribution between Au and Cu and increase stability of the Au0.25Cu0.75 electrode as observed in XAFS, indicates that the electronic effect in the cluster is also one of the governing factors for PEC activity. Secondly, formation of a surface CuOx layer, protects against further corrosion of the metallic AuCu BNCs cores. Third, reduced recombination of charge carriers is indicated by lower photoluminescent (PL) intensity compared to pristine TNTs and all other electrodes except pure gold, as observed in PL spectra. This implies that the generated charge carriers are efficiently separated by Au0.25Cu0.75 NCs acting as electron sinks and easily available for redox reactions. Fourth, the highest interfacial charge transfer efficiency is evidenced by the electrochemical impedance spectroscopy (EIS), leading to more efficacious charge migration and separation, facilitating the water oxidation surface reaction. A final beneficial factor is the uniform deposition of well-defined, size- and composition-controlled, ligand-free BNCs. Such BNCs provide more effective surface sites to the reaction medium, in contrast to electrodes synthesized by e.g. sol-gel methods, where (in)organic residues on metal surfaces may decrease the efficiency.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-07-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:206758 Serial 9293
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Author Pascucci, F.
Title Superfluidity in exciton bilayer systems : Josephson effect and collective modes as definitive identification-markers Type (down) Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume Issue Pages xiii, 126 p.
Keywords Doctoral thesis; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT)
Abstract This thesis explores superfluidity in exciton bilayer systems, semiconductor structures with two thin conducting layers, one doped with electrons and the other with holes, separated by a few nanometers. Theoretical predictions suggest these systems can exhibit superfluid, supersolid, exciton normal solid, and Wigner crystal phases. Identifying clear markers of superfluidity is crucial due to experimental challenges in confirming excitonic superfluidity. This thesis focuses on two phenomena: the Josephson effect and density collective modes. For the Josephson effect, we propose an exciton bilayer Josephson junction in double monolayer Transition Metal Dichalcogenides. We suggest using the Shapiro method to measure the exciton Josephson current and propose fabricating the device with a tunable potential-barrier height. In low potential-barrier regions, the exciton superfluid flows over the barrier, while in high potential-barrier regions, flow is driven by quantum tunnelling. This helps delineate the boundary between Bose-Einstein Condensate (BEC) and BCS-BEC crossover regimes. For density collective modes, we examine low-temperature behaviour to identify the normal-superfluid transition as a function of density. In the normal state at high density, the system exhibits low-energy optic and acoustic modes. As density decreases, entering the superfluid phase, the response changes, with the superfluid gap blocking these modes. We expect pair-breaking collective modes to appear at the onset of exciton superfluidity due to the Coulomb interaction. Our theoretical model developed using a path-integral approach and the Hartree-Fock approximation, includes screening and intralayer correlations. We calculate gap and number equations governing superfluid phase behaviour, showing that intralayer correlations enhance screening, especially in the BCS-BEC crossover regime. This leads to a reduced superfluid gap, a shift in the BEC to BCS-BEC crossover boundary to lower densities, and the disappearance of a predicted minimum in electron-hole pair size. This study advances the understanding of superfluidity in exciton bilayer systems, providing theoretical predictions and experimental proposals. By identifying clear markers of superfluidity, this work contributes to the broader effort of realizing and characterizing excitonic condensed phases in realistic systems.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-09-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:207852 Serial 9318
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Author Ninakanti, R.
Title Synthesis and electron microscopy characterization of novel core-shell and self-assembled nanostructures for plasmon-enhanced photocatalysis Type (down) Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume Issue Pages 163 p.
Keywords Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Antwerp engineering, PhotoElectroChemistry & Sensing (A-PECS)
Abstract The global challenge posed by increasing levels of greenhouse gases and the associated detrimental impacts of global warming necessitate a strategic shift from traditional fossil fuel-based energy systems to more sustainable, renewable, and circular energy and material solutions. Consequently, the potential of photoactive nanoparticles, particularly those that harness light-driven processes, has captured extensive scientific interest as a viable approach to mitigating energy and environmental challenges on a global scale. Although, the adoption of solar light based solutions in the chemical industry has been very less due to sluggish reaction rates and its cascading effects on its economics. The primary focus of this dissertation is the study of plasmonic metal nanoparticles and metal oxide nanoparticles, emphasizing their applications in light-driven energy conversion. The distinctive properties of plasmonic materials, especially surface plasmon resonance (SPR), are pivotal in these applications. SPR involves the oscillation of electron clouds at the surface of nanoparticles when resonating with incident electromagnetic radiation, significantly enhancing solar radiation absorption. This feature is crucial for addressing the limitations of semiconductor photocatalysts like TiO2, which typically exhibit restricted absorption of solar irradiation. The objective of this dissertation is to further optimize the plasmonic enhancement mechanisms by strategically tuning the interactions between plasmonic nanoparticles and TiO2. This is achieved through the development of core-shell nanostructures and the self-assembly of supraparticles, designed to enhance plasmonic photocatalytic systems. The dissertation begins by elucidating the basic concepts and ideations behind the construction of these nanostructures and their roles in enhancing plasmonic photocatalysis, focusing on mechanisms such as near-electric field enhancement, electron transfer, and enhanced photon absorption. To achieve these objectives, modified synthesis techniques were developed to fabricate novel Au@TiO2 core-shell structures with precisely controlled TiO2 shell thickness and self-assembled Au-TiO2 supraparticles with variable sizes. The thesis further delves into the structural characterization of these synthesized nanoparticles, introducing both basic and advanced electron microscopy techniques. For the specific applications of these structures, it was found that Au@TiO2 core-shell nanoparticles with an optimal 4nm TiO2 shell thickness show significant enhancement in the hydrogen evolution reaction. Additionally, the largest Au-TiO2 supraparticles demonstrate superior efficacy in hydrogen peroxide generation. This work not only deepens the scientific understanding of plasmonic materials but also contributes to the development of renewable energy materials.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-07-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:206768 Serial 9320
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Author Cautaerts, N.; Lamm, S.; Stergar, E.; Pakarinen, J.; Yang, Y.; Hofer, C.; Schnitzer, R.; Felfer, P.; Verwerft, M.; Delville, R.; Schryvers, D.
Title Atom probe tomography data collection from DIN 1.4970 (15-15Ti) austenitic stainless steel irradiated with Fe ions Type (down) Dataset
Year 2020 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Electron microscopy for materials research (EMAT)
Abstract This dataset comprises a large collection of atom probe tomography datasets collected from DIN 1.4970 alloy that was irradiated with Fe ions at different conditions. The DIN 1.4970 alloy is an austenitic stainless steel with 15 wt% Cr, 15 wt% Ni, a small addition of Ti. The full composition and characterization of our material can be found published elsewhere [1,2]. Some of our material was subjected to ageing heat treatments at different temperatures for different times. Small samples of our original material and aged material was irradiated at the Michigan Ion Beam Laboratory in 2017 with 4.5 MeV Fe ions up to 40 dpa at an average dose rate of 2×10−4 dpa/s. This was done at three different temperatures: 300, 450, and 600 ºC. Atom probe samples were made of the irradiated layers (approximately 1.5 micron deep) with focused ion beam and mounted on Microtip coupons. APT measurements took place on three CAMECA LEAP-HR systems located at CAES in Idaho Falls, USA (files beginning with R33), at Montanuniversität Leoben in Leoben, Austria (R21) and at Friedrich–Alexander University in Erlangen, Germany (R56).
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Corporate Author Thesis
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Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
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Impact Factor Times cited Open Access Not_Open_Access
Notes ; ; Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:169127 Serial 6454
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Author Skorikov, A.; Heyvaert, W.; Albrecht, W.; Pelt, D.M.; Bals, S.
Title EMAT Simulated 3D Nanoparticle Structures Dataset Type (down) Dataset
Year 2021 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Electron microscopy for materials research (EMAT)
Abstract This dataset contains 1000 simulated nanoparticle-like 3D structures and noisy EDX-like elemental maps based on them. These data are intended to be used for quantitative analysis of data processing methods in (EDX) tomography of nanoparticles and training the data-driven approaches for these tasks. The dataset is structured as follows: voxel_data/clean 3D voxel grid representation of the simulated nanoparticles. Voxel intensities are adjusted so that the total intensity equals 103. All 3D structures have unique identifiers in 0..999 range. The data derived from a 3D structure preserves this unique identifier. sinograms/clean Tilt series of projection images obtained from the corresponding 3D structures over an angular range of -75..75 degrees with a tilt step of 10 degrees to simulate a typical tilt series used in EDX tomography. Total intensity in each projection image equals 103. sinograms/noisy Tilt series of projection images corrupted with Poisson noise and an additional spatially uniform background noise. projections/clean Projection images extracted from the clean tilt series at 0 degrees tilt angle. projections/noisy Projection images extracted from the noisy tilt series at 0 degrees tilt angle. images/clean Visualizations of the clean projections as PNG images with the intensity range adjusted to 0..255 images/noisy Visualizations of the noisy projections as PNG images with the intensity range adjusted to 0..255
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:180615 Serial 6838
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Author Guzzinati, G.; Ghielens, W.; Mahr, C.; Béché, A.; Rosenauer, A.; Calders, T.; Verbeeck, J.
Title Electron Bessel beam diffraction patterns, line scan of Si/SiGe multilayer Type (down) Dataset
Year 2019 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; ADReM Data Lab (ADReM); Electron microscopy for materials research (EMAT)
Abstract
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Notes Approved no
Call Number UA @ admin @ c:irua:169114 Serial 6865
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Author Guzzinati, G.; Das, P.P.; Zompra, A., A.; Nicopoulos, S.; Verbeeck, J.
Title Electron energy loss spectra of several organic compounds Type (down) Dataset
Year 2020 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Electron microscopy for materials research (EMAT)
Abstract We placed crystals of different compounds to explore the possibility of fingerprinting them through EELS. Here are representative datasets of 7 different compounds: b-cyclodextrin hexacarboxy cyclohexane tannin TH-15 peptide TH-27 peptide two different forms of piroxicam The datasets were collected at EMAT, using a monochromated FEI Titan3 TEM, within the scope of an EUSMI request. More information as well as analysis methodologies adopted for the data are detailed in the paper: Das et al. “Reliable Characterization of Organic & Pharmaceutical Compounds with High Resolution Monochromated EEL Spectroscopy”, Polymers 2020, 12(7), 1434.
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ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:180654 Serial 6866
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Author Samaeeaghmiyoni, V.; Cordier, P.; Demouchy, S.; Bollinger, C.; Gasc, J.; Mussi, A.; Schryvers, D.; Idrissi, H.
Title Research data supporting for Stress-induced amorphization triggers deformation in the lithospheric mantle Type (down) Dataset
Year 2020 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Electron microscopy for materials research (EMAT)
Abstract
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Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:180668 Serial 6881
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Author Guzzinati, G.; Béché, A.; McGrouther, D.; Verbeeck, J.
Title Rotation of electron beams in the presence of localised, longitudinal magnetic fields Type (down) Dataset
Year 2019 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Electron microscopy for materials research (EMAT)
Abstract Electron Bessel beams have been generated by inserting an annular aperture in the illumination system of a TEM. These beams have passed through a localised magnetic field. As a result a low amount of image rotation (which is expected to be proportional to the longitudinal component of the magnetic field) is observed in the far field. A measure of this rotation should give access to the magneti field. The two datasets have been acquired in a FEI Titan3 microscope, operated at 300kV. The file focalseries.tif contains a series of images acquired varying the magnetic field through the objective lens. The file lineprofile.ser contains a series of images acquired by scanning the beam over a sample with several magnetised nanopillars. For reference, check the associated publication.
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Language Wos Publication Date
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Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:169135 Serial 6883
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Author Jannis, D.; Müller-Caspary, K.; Béché, A.; Oelsner, A.; Verbeeck, J.
Title Spectrocopic coincidence experiment in transmission electron microscopy Type (down) Dataset
Year 2019 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Electron microscopy for materials research (EMAT)
Abstract This dataset contains individual EEL and EDX events where for every event (electron or X-ray), their energy and time of arrival is stored. The experiment was performed in a transmission electron microscope (Tecnai Osiris) at 200 keV. The material investigated is an Al-Mg-Si-Cu alloy. The 'full_dataset.mat' contains the full dataset and the 'subset.mat' has the first five frames of the full dataset. The attached 'EELS-EDX.ipynb' is a jupyter notebook file. This file describes the data processing in order to observe the temporal correlation between the electrons and X-rays.
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Language Wos Publication Date
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ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:169112 Serial 6888
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Author Idrissi, H.; Samaee, V.; Lumbeeck, G.; van der Werf, T.; Pardoen, T.; Schryvers, D.; Cordier, P.
Title Supporting data for “In situ Quantitative Tensile Tests on Antigorite in a Transmission Electron Microscope” Type (down) Dataset
Year 2019 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Electron microscopy for materials research (EMAT)
Abstract The determination of the mechanical properties of serpentinites is essential towards the understanding of the mechanics of faulting and subduction. Here, we present the first in situ tensile tests on antigorite in a transmission electron microscope. A push-to-pull deformation device is used to perform quantitative tensile tests, during which force and displacement are measured, while the microstructure is imaged with the microscope. The experiments have been performed at room temperature on beams prepared by focused ion beam. The specimens are not single crystals despite their small sizes. Orientation mapping indicated that some grains were well-oriented for plastic slip. However, no dislocation activity has been observed even though engineering tensile stress went up to 700 MPa. We show also that antigorite does not exhibit an pure elastic-brittle behaviour since, despite the presence of defects, the specimens underwent plastic deformation and did not fail within the elastic regime. Instead, we observe that strain localizes at grain boundaries. All observations concur to show that under our experimental conditions, grain boundary sliding is the dominant deformation mechanism. This study sheds a new light on the mechanical properties of antigorite and calls for further studies on the structure and properties of grain boundaries in antigorite and more generally in phyllosilicates.
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Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:169107 Serial 6891
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Author Nakazato, R.; Matsumoto, K.; Yamaguchi, N.; Cavallo, M.; Crocella, V.; Bonino, F.; Quintelier, M.; Hadermann, J.; Rosero-Navarro, N.C.; Miura, A.; Tadanaga, K.
Title CO2 Electrochemical Reduction with Zn-Al Layered Double Hydroxide-Loaded Gas-Diffusion Electrode (Supporting Information) Type (down) Dataset
Year 2023 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Electron microscopy for materials research (EMAT)
Abstract Carbon dioxide electrochemical reduction (CO2ER) has attracted considerable attention as a technology to recycle CO2 into raw materials for chemicals using renewable energies. We recently found that Zn-Al layered double hydroxides (Zn-Al LDH) have the CO-forming CO2ER activity. However, the activity was only evaluated by using the liquid-phase CO2ER. In this study, Ni-Al and Ni-Fe LDHs as well as Zn-Al LDH were synthesized using a facile coprecipitation process and the gas-phase CO2ER with the LDH-loaded gas-diffusion electrode (GDE) was examined. The products were characterized by XRD, STEM-EDX, BF-TEM and ATR-IR spectroscopy. In the ATR-IR results, the interaction of CO2 with Zn-Al LDH showed a different carbonates evolution with respect to other LDHs, suggesting a different electrocatalytic activity. The LDH-loaded GDE was prepared by simple drop-casting of a catalyst ink onto carbon paper. For gas-phase CO2ER, only Zn-Al LDH exhibited the CO2ER activity for carbon monoxide (CO) formation. By using different potassium salt electrolytes affording neutral to strongly basic conditions, such as KCl, KHCO3 and KOH, the gas-phase CO2ER with Zn-Al LDH-loaded GDE showed 1.3 to 2.1 times higher partial current density for CO formation than the liquid-phase CO2ER.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001079191200001 Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:200933 Serial 9010
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Author Annys, A.; Jannis, D.; Verbeeck, J.
Title Core-loss EELS dataset and neural networks for element identification Type (down) Dataset
Year 2023 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Electron microscopy for materials research (EMAT)
Abstract We present a large dataset containing simulated core-loss electron energy loss spectroscopy (EELS) spectra with the elemental content as ground-truth labels. Additionally we present some neural networks trained on this data for element identification.  The simulated dataset contains zero padded core-loss spectra from 0 to 3072 eV, which represents 107 core-loss edges through all 80 elements from Be up to Bi. The core-loss edges are calculated from the generalised oscillator strength (GOS) database presented by Zhang et al.[1] Generic fine structures using lifetime broadened peaks are used to imitate fine structure due to solid-state effects in experimental spectra. Generic low-loss regions are used to imitate the effect of multiple scattering. Each spectrum contains at least one edge of a given query element and possibly additional edges depending on samples drawn from The Materials Project [2]. The dataset contains for each of the 80 elements: 7000 training spectra, 1500 test spectra, 600 validation spectra and 100 spectra representing only the query element. This results in a total 736 000 labeled spectra. Code on how to  – read the simulated data – transform HDF5 format to TFRecord format – train and evaluate neural networks using the simulated data – use the trained networks for automated element identification is available on GitHub at arnoannys/EELS_ID A full report on the simulation of the dataset and the training and evaluation of the neural networks can be found at:                    Annys, A., Jannis, D. & Verbeeck, J. Deep learning for automated materials characterisation in core-loss electron energy loss spectroscopy. Sci Rep 13, 13724 (2023). https://doi.org/10.1038/s41598-023-40943-7 [1] Zezhong Zhang, Ivan Lobato, Daen Jannis, Johan Verbeeck, Sandra Van Aert, & Peter Nellist. (2023). Generalised oscillator strength for core-shell electron excitation by fast electrons based on Dirac solutions (1.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.7729585 [2] Anubhav Jain, Shyue Ping Ong, Geoffroy Hautier, Wei Chen, William Davidson Richards, Stephen Dacek, Shreyas Cholia, Dan Gunter, David Skinner, Gerbrand Ceder, Kristin A. Persson; Commentary: The Materials Project: A materials genome approach to accelerating materials innovation. APL Mater 1 July 2013; 1 (1): 011002. [https://doi.org/10.1063/1.4812323](https://doi.org/10.1063/1.4812323)
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Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:203391 Serial 9015
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Author Zhang, Z.; Lobato, I.; Brown, H.; Jannis, D.; Verbeeck, J.; Van Aert, S.; Nellist, P.
Title Generalised oscillator strength for core-shell electron excitation by fast electrons based on Dirac solutions Type (down) Dataset
Year 2023 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Electron microscopy for materials research (EMAT)
Abstract Inelastic excitation as exploited in Electron Energy Loss Spectroscopy (EELS) contains a rich source of information that is revealed in the scattering process. To accurately quantify core-loss EELS, it is common practice to fit the observed spectrum with scattering cross-sections calculated using experimental parameters and a Generalized Oscillator Strength (GOS) database [1].   The GOS is computed using Fermi’s Golden Rule and orbitals of bound and excited states. Previously, the GOS was based on Hartree-Fock solutions [2], but more recently Density Functional Theory (DFT) has been used [3]. In this work, we have chosen to use the Dirac equation to incorporate relativistic effects and have performed calculations using Flexible Atomic Code (FAC) [4]. This repository contains a tabulated GOS database based on Dirac solutions for computing double differential cross-sections under experimental conditions.   We hope the Dirac-based GOS database can benefit the EELS community for both academic use and industry integration.   Database Details: – Covers all elements (Z: 1-108) and all edges – Large energy range: 0.01 – 4000 eV – Large momentum range: 0.05 -50 Å-1 – Fine log sampling: 128 points for energy and 256 points for momentum – Data format: GOSH [3]   Calculation Details: – Single atoms only; solid-state effects are not considered – Unoccupied states before continuum states of ionization are not considered; no fine structure – Plane Wave Born Approximation – Frozen Core Approximation is employed; electrostatic potential remains unchanged for orthogonal states when – core-shell electron is excited – Self-consistent Dirac–Fock–Slater iteration is used for Dirac calculations; Local Density Approximation is assumed for electron exchange interactions; continuum states are normalized against asymptotic form at large distances – Both large and small component contributions of Dirac solutions are included in GOS – Final state contributions are included until the contribution of the previous three states falls below 0.1%. A convergence log is provided for reference.   Version 1.1 release note: – Update to be consistent with GOSH data format [3], all the edges are now within a single hdf5 file. A notable change in particular, the sampling in momentum is in 1/m, instead of previously in 1/Å. Great thanks to Gulio Guzzinati for his suggestions and sending conversion script.  Version 1.2 release note: – Add “File Type / File version” information [1] Verbeeck, J., and S. Van Aert. Ultramicroscopy 101.2-4 (2004): 207-224. [2] Leapman, R. D., P. Rez, and D. F. Mayers. The Journal of Chemical Physics 72.2 (1980): 1232-1243. [3] Segger, L, Guzzinati, G, & Kohl, H. Zenodo (2023). doi:10.5281/zenodo.7645765 [4] Gu, M. F. Canadian Journal of Physics 86(5) (2008): 675-689.
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Series Editor Series Title Abbreviated Series Title
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Impact Factor Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:203392 Serial 9042
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Author Grünewald, L.; Chezganov, D.; De Meyer, R.; Orekhov, A.; Van Aert, S.; Bogaerts, A.; Bals, S.; Verbeeck, J.
Title Supplementary Information for “In-situ Plasma Studies using a Direct Current Microplasma in a Scanning Electron Microscope” Type (down) Dataset
Year 2023 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Supplementary information for the article “In-situ Plasma Studies using a Direct Current Microplasma in a Scanning Electron Microscope” containing the videos of in-situ SEM imaging (mp4 files), raw data/images, and Jupyter notebooks (ipynb files) for data treatment and plots. Link to the preprint: https://doi.org/10.48550/arXiv.2308.15123 Explanation of the data files can be found in the Information.pdf file. The Videos folder contains the in-situ SEM image series mentioned in the paper. If there are any questions/bugs, feel free to contact me at lukas.grunewaldatuantwerpen.be
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Language Wos Publication Date
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Impact Factor Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:203389 Serial 9100
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Author Cioni, M.; Delle Piane, M.; Polino, D.; Rapetti, D.; Crippa, M.; Arslan Irmak, E.; Pavan, G.M.; Van Aert, S.; Bals, S.
Title Data for Sampling Real‐Time Atomic Dynamics in Metal Nanoparticles by Combining Experiments, Simulations, and Machine Learning Type (down) Dataset
Year 2024 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Even at low temperatures, metal nanoparticles (NPs) possess atomic dynamics that are key for their properties but challenging to elucidate. Recent experimental advances allow obtaining atomic‐resolution snapshots of the NPs in realistic regimes, but data acquisition limitations hinder the experimental reconstruction of the atomic dynamics present within them. Molecular simulations have the advantage that these allow directly tracking the motion of atoms over time. However, these typically start from ideal/perfect NP structures and, suffering from sampling limits, provide results that are often dependent on the initial/putative structure and remain purely indicative. Here, by combining state‐of‐the‐art experimental and computational approaches, how it is possible to tackle the limitations of both approaches and resolve the atomistic dynamics present in metal NPs in realistic conditions is demonstrated. Annular dark‐field scanning transmission electron microscopy enables the acquisition of ten high‐resolution images of an Au NP at intervals of 0.6 s. These are used to reconstruct atomistic 3D models of the real NP used to run ten independent molecular dynamics simulations. Machine learning analyses of the simulation trajectories allows resolving the real‐time atomic dynamics present within the NP. This provides a robust combined experimental/computational approach to characterize the structural dynamics of metal NPs in realistic conditions.
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Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:205843 Serial 9143
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Author Lembrechts, J.; Clavel, J.; Lenoir, J.; Haider, S.; McDougall, K.; Nunez, M.; Alexander, J.; Barros, A.; Milbau, A.; Seipel, T.; Verbruggen, E.; Nijs, I.
Title Dataset: Roadside disturbance promotes plant communities with arbuscular mycorrhizal associations in mountain regions worldwide Type (down) Dataset
Year 2024 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Plant and Ecosystems (PLECO) – Ecology in a time of change
Abstract Aim: We aimed to assess the impact of road disturbances on the dominant mycorrhizal types in ecosystems at the global level and how this mechanism can potentially lead to lasting plant community changes. Location: Globally distributed mountain regions Time Period: 2007-2018 Taxa studied: Plants (linked to their associated mycorrhizal fungi) Methods: We used a database of coordinated plant community surveys following mountain roads from 894 plots in 11 mountain regions across the globe in combination with an existing database of mycorrhizal-plant associations in order to approximate the relative abundance of mycorrhizal types in natural and disturbed environments. Results: Our findings show that roadside disturbance promotes the cover of plants associated with arbuscular mycorrhizal (AM) fungi. This effect is especially strong in colder mountain environments and in mountain regions where plant communities are dominated by ectomycorrhizal (EcM) or ericoid-mycorrhizal (ErM) associations. Furthermore, non-native plant species, which we confirmed to be mostly AM plants, are more successful in environments dominated by AM associations. Main Conclusions: These biogeographical patterns suggest that changes in mycorrhizal types could be a crucial factor in the worldwide impact of anthropogenic disturbances on mountain ecosystems. Indeed, roadsides foster AM-dominated systems, where AM-fungi might aid AM-associated plant species while potentially reducing the biotic resistance against invasive non-native species, often also associated with AM networks. Restoration efforts in mountain ecosystems will have to contend with changes in the fundamental make-up of EcM- and ErM plant communities induced by roadside disturbance.
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Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:206132 Serial 9198
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Author Vanhooydonck, A.; Vleugels, J.; Parrilla Pons, M.; Clerx, P.; Watts, R.
Title Digital Repository : Optimizing high accuracy 8K LCD 3D-printed Hollow Microneedles: Methodology and ISO-7864:2016 Guided Evaluation for Enhanced Skin Penetration Type (down) Dataset
Year 2024 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Engineering sciences. Technology; Product development; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab); Antwerp engineering, PhotoElectroChemistry & Sensing (A-PECS)
Abstract This dataset contains 30 STL files of different geometries of microneedles (face angle, inner diameter, outer diameter, wall thickness) which are 3D printable using mSLA printers.
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Language Wos https://github.com/AndresVHD/Optimizing_high_accuracy_8K-LCD_3D-printed_Hollow_Microneedles-Digital_ Publication Date
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Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record; https://github.com/AndresVHD/Optimizing_high_accuracy_8K-LCD_3D-printed_Hollow_Microneedles-Digital_Supplement/tree/main/CAD_Files/MN_Configurations
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:208524 Serial 9283
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Author Zhang, Y.; Grünewald, L.; Cao, X.; Abdelbarey, D.; Zheng, X.; Rugeramigabo, E.P.; Zopf, M.; Verbeeck, J.; Ding, F.
Title Supplementary Information and Data for “Unveiling the 3D Morphology of Epitaxial GaAs/AlGaAs Quantum Dots” Type (down) Dataset
Year 2024 Publication Abbreviated Journal
Volume Issue Pages
Keywords Dataset; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Raw and processed TEM and AFM data for the article Unveiling the 3D Morphology of Epitaxial GaAs/AlGaAs Quantum Dots.
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Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:208086 Serial 9319
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Author Van Oijstaeijen, W.
Title Green infrastructure and local implementation : (green) bridging the gap between research and practice Type (down) Administrative Services
Year 2023 Publication Abbreviated Journal
Volume Issue Pages xvii, 194 p.
Keywords Administrative Services; Doctoral thesis; Engineering sciences. Technology; Engineering Management (ENM)
Abstract Climate change is an ever-increasing threat to our planet, with the urbanisation of previously open spaces exacerbating the issue. The loss of open space leads to a decrease in ecosystem services, which negatively impacts the liveability in urbanised environments, and beyond. The incorporation of green infrastructure (GI) into the built environment is acknowledged as an effective and multi-functional measure to make our living environment resilient and future-proof. Notwithstanding that the local level is essential for effective GI implementation, research into local decision making is very limited. This thesis therefore aims to address two significant gaps in the implementation of GI. The first objective is to bridge the science-policy gap by integrating scientific knowledge on ES and GI into local decision-making processes. In this context, the policy dimension within this thesis involves the process of translating overarching policy objectives into practical actions within local decision-making practices, abstracting from the intricacies of higher-level policymaking itself. The second objective focuses on the people-policy gap, which involves understanding stakeholders' perspectives and priorities regarding GI and its associated ecosystem services. Through stated preference valuation techniques (discrete choice experiments and a best-worst scaling experiment), multi-stakeholder GI perceptions are gathered. Finally, a novel tool to GI valuation is developed, acknowledging the different stakeholder views and building on the insights of collaborative tool development and design. By gaining insights into the demand, prioritisation, and provision of GI from the two most important stakeholder groups at the local level (residents and local decision-makers), this research aims to foster effective communication and alignment between public preferences and policy implementation. Ultimately, addressing these gaps will contribute to more informed planning and decision-making practices related to green infrastructure. The overall goal of this thesis is to enhance the uptake of GI knowledge in the local decision-making context, proposing pathways to facilitate and optimise investments in public GI.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 978-90-5728-814-2 Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:199925 Serial 9206
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Author Groenendijk, D.J.; Autieri, C.; van Thiel, T.C.; Brzezicki, W.; Hortensius, J.R.; Afanasiev, D.; Gauquelin, N.; Barone, P.; van den Bos, K.H.W.; van Aert, S.; Verbeeck, J.; Filippetti, A.; Picozzi, S.; Cuoco, M.; Caviglia, A.D.
Title Berry phase engineering at oxide interfaces Type (down) A1 Journal article
Year 2020 Publication Abbreviated Journal Phys. Rev. Research
Volume 2 Issue 2 Pages 023404
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Three-dimensional strontium ruthenate (SrRuO3) is an itinerant ferromagnet that features Weyl points acting as sources of emergent magnetic fields, anomalous Hall conductivity, and unconventional spin dynamics. Integrating SrRuO3 in oxide heterostructures is potentially a novel route to engineer emergent electrodynamics, but its electronic band topology in the two-dimensional limit remains unknown. Here we show that ultrathin SrRuO3 exhibits spin-polarized topologically nontrivial bands at the Fermi energy. Their band anticrossings show an enhanced Berry curvature and act as competing sources of emergent magnetic fields. We control their balance by designing heterostructures with symmetric (SrTiO3/SrRuO3/SrTiO3 and SrIrO3/SrRuO3/SrIrO3) and asymmetric interfaces (SrTiO3/SrRuO3/SrIrO3). Symmetric structures exhibit an interface-tunable single-channel anomalous Hall effect, while ultrathin SrRuO3 embedded in asymmetric structures shows humplike features consistent with multiple Hall contributions. The band topology of two-dimensional SrRuO3 proposed here naturally accounts for these observations and harmonizes a large body of experimental results.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000603642700008 Publication Date 2020-06-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2643-1564 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 58 Open Access OpenAccess
Notes Nederlandse Organisatie voor Wetenschappelijk Onderzoek; Fonds Wetenschappelijk Onderzoek; European Research Council; Horizon 2020, 677458 770887 731473 ; Fondazione Cariplo, 2013-0726 ; Narodowe Centrum Nauki, 2016/23/B/ST3/00839 ; Fundacja na rzecz Nauki Polskiej; Universiteit Antwerpen; Vlaamse regering; Approved Most recent IF: NA
Call Number EMAT @ emat @c:irua:172462 Serial 6401
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