1. Beyond surface area : enhanced pseudocapacitive properties of cobalt layered double hydroxide through structural modificationsAnja Siher, Ksenija Maver, Uroš Luin, Albin Pintar, Iztok Arčon, Andraž Mavrič, 2025, izvirni znanstveni članek Opis: Cobalt hydroxide and other first-row transition metal hydroxides have gained significant attention as pseudocapacitor materials due to their rapid and reversible redox processes. Their layered structures facilitate interactions between electrolyte anions and cobalt cation sites within the bulk of the material, enabling higher charge density and extending redox activity beyond the particle surface. By controlled precipitation under hydrothermal conditions, the structure and morphology of cobalt hydroxides can be optimized to enhance electrochemical performance. Challenging conventional assumptions, surface area alone is not the primary factor driving increased pseudocapacitive performance. The hexagonal hydrotalcite-like structure, characterized by lower skeletal density and larger basal plane spacing, outperforms the monoclinic cobalt carbonate hydroxide structure, achieving an order of magnitude higher capacitance. In situ X-ray absorption spectroscopy provides critical insights into the pseudocapacitive behavior, revealing enhanced accessibility of Co2+ sites for electrochemical oxidation. While monoclinic cobalt carbonate hydroxide exhibits minimal changes in the Co2+ oxidation state, indicative of surface-limited redox activity, the hydrotalcite-like cobalt hydroxides show substantial shifts in the Co K-edge position, highlighting oxidation of Co2+ sites throughout the bulk.
Ključne besede: pseudocapacitors, layered-double hydroxides, cobalt hydroxide, redox processes, in situ x-ray absorption spectroscopy
Objavljeno v RUNG: 14.03.2025; Ogledov: 621; Prenosov: 7
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4. Insights into the size-resolved dust emission from field measurements in the Moroccan SaharaCristina González-Flórez, Martina Klose, Andrés Alastuey, Sylvain Dupont, Jerónimo Escribano, Vicken Etyemezian, Adolfo Gonzalez-Romero, Yue Huang, Konrad Kandler, Jesús Yus-Díez, 2023, izvirni znanstveni članek Opis: Atmospheric mineral dust consists of tiny mineral particles that are emitted by wind erosion from arid regions. Its particle size distribution (PSD) affects its impact on the Earth's system. Nowadays, there is an incomplete understanding of the emitted dust PSD and a lot of debate about its variability. Here, we try to address these issues based on the measurements performed during a wind erosion and dust emission field campaign in the Moroccan Sahara within the framework of FRAGMENT project.
Ključne besede: aerosol particles, mineral dust, emission processes, climate
Objavljeno v RUNG: 23.10.2023; Ogledov: 2479; Prenosov: 7
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6. The mass fallback rate of the debris in relativistic stellar tidal disruption eventsTaj Jankovič, 2022, objavljeni povzetek znanstvenega prispevka na konferenci Opis: Highly energetic stellar tidal disruption events (TDEs) provide a way to study black hole characteristics and their environment. We simulate TDEs in a general relativistic and Newtonian description of a supermassive black hole's gravity. Stars, which are placed on parabolic orbits with different impact parameters, are constructed with the stellar evolution code MESA and therefore have realistic stellar density profiles. We focus our analysis on the mass fallback rate of the debris, which can trace the observed light curve of TDEs. I will present the dependence of the mass fallback rate of the debris on the impact parameter, stellar mass and age as well as the black hole's spin and the choice of the gravity's description.
Ključne besede: black hole physics, hydrodynamics, relativistic processes
Objavljeno v RUNG: 21.10.2022; Ogledov: 2940; Prenosov: 8
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7. Photocatalytic sol-gel/P25 TiO [sub] 2 coatings for water treatment : degradation of 7 selected pharmaceuticals (CO3:IL02)Lev Matoh, Boštjan Žener, Marin Kovačić, Hrvoje Kušić, Iztok Arčon, Meta Levstek, Urška Lavrenčič Štangar, 2022, izvirni znanstveni članek Opis: The effect of different water matrices on the photocatalytic degradation of dissolved pharmaceuticals was
explored. The focus was on the degradation efficiencies in wastewater effluent from a bioreactor and water
effluent from a central wastewater treatment plant and comparing the results with degradation in deionized H2O.
The compounds tested included: oxytetracycline, marbofloxacin, ibuprofen, diclofenac, phenytoin, ciprofloxacin,
sulfamethoxazole. For the experiments performed in this study, a compact packed-bed photocatalytic reactor was
used in which the hybrid TiO2 photocatalyst (sol-gel/P25) was deposited on ~3 mm glass beads. As expected, the
reactions proceed more slowly in wastewater than in deionized water, yet it is shown that removal of the
compounds from the water is still possible even when other organic molecules are present. Total organic carbon
measurements have shown that complete mineralization takes place albeit at slower rates than the initial
degradation of parent compounds. The results show that an acidic pH can increase the reaction rates and the
adsorption on the photocatalyst surface. Analyses of the degradation intermediates were performed using tandem
liquid chromatography triple-quadrupole mass spectrometry system. Additionally, X-ray absorption spectroscopy
was applied to get insight into the local structure of the photocatalyst before and after use. Understanding the
effects that different wastewater compositions have on photocatalytic reactions will help to refine the potential
applications of the technology.
Ključne besede: titanium dioxide, sol-gel processes, functionla applications, water treatment
Objavljeno v RUNG: 30.09.2022; Ogledov: 2920; Prenosov: 0
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8. Characterization of electrochemical processes in metal-organic batteries by X-ray Raman spectroscopyAva Rajh, Iztok Arčon, Klemen Bučar, Matjaž Žitnik, Marko Petric, Alen Vižintin, Jan Bitenc, Urban Košir, Robert Dominko, Hlynur Gretarsson, Martin Sundermann, Matjaž Kavčič, 2022, izvirni znanstveni članek Opis: X-ray Raman spectroscopy (XRS) is an emerging
spectroscopic technique that utilizes inelastic scattering of hard Xrays
to study X-ray absorption edges of low Z elements in bulk
material. It was used to identify and quantify the amount of
carbonyl bonds in a cathode sample, in order to track the redox
reaction inside metal−organic batteries during the charge/
discharge cycle. XRS was used to record the oxygen K-edge
absorption spectra of organic polymer cathodes from different
multivalent metal−organic batteries. The amount of carbonyl bond
in each sample was determined by modeling the oxygen K-edge
XRS spectra with the linear combination of two reference compounds that mimicked the fully charged and the fully discharged
phases of the battery. To interpret experimental XRS spectra, theoretical calculations of oxygen K-edge absorption spectra based on
density functional theory were performed. Overall, a good agreement between the amount of carbonyl bond present during different
stages of battery cycle, calculated from linear combination of standards, and the amount obtained from electrochemical
characterization based on measured capacity was achieved. The electrochemical mechanism in all studied batteries was confirmed to
be a reduction of double carbonyl bond and the intermediate anion was identified with the help of theoretical calculations. X-ray
Raman spectroscopy of the oxygen K-edge was shown to be a viable characterization technique for accurate tracking of the redox
reaction inside metal−organic batteries.
Ključne besede: X-ray Raman spectroscopy, meta-organic batteries, oxygen K-edge XANES, electrochemical processes
Objavljeno v RUNG: 24.03.2022; Ogledov: 3027; Prenosov: 22
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9. Business-information system for smart homes based on Z-Wave technology : diploma thesisDavid Manchevski, 2021, diplomsko delo Opis: The goal of this thesis is to show how to create a system, that can be implemented in today’s market of smart home modules.
This will be done by introducing how the Z-Wave technology works, how it can be implemented in the user’s home. Furthermore, the functionalities of the Z-Wave technology will be presented together with the Z-Wave modules and their everyday uses. In addition, the business-information system can put on display how a smart home company operates, how the data is distributed between the departments of said smart home company. The business-information system is shown with the help of a data flow diagrams, entity relationship diagrams and a database of the data that is stored inside the particular database. This system will be used by a user interested in the buying the smart home technology products, partners, Z-wave certifiers, reclamation department.
Ključne besede: Z-Waves, smart homes, business-information systems, entity-relationship, processes, data flows, data stores, modules, diploma thesis
Objavljeno v RUNG: 24.01.2022; Ogledov: 3840; Prenosov: 94
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10. Aeolian dispersal of bacteria in southwest Greenland: their sources, abundance, diversity and physiological statesTina Šantl Temkiv, Ulrich Gosewinkel, Piotr Starnawski, Mark Lever, Kai Finster, 2018, izvirni znanstveni članek Ključne besede: arctic microbial communities, aeolian dispersal, community assembly, 16S ribosomal RNA, microbial activity, atmospheric processes
Objavljeno v RUNG: 04.01.2021; Ogledov: 3886; Prenosov: 0
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