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3. Role of Cu current collector on electrochemical mechanism of Mg–S batteryAna Robba, Maja Mežnar, Alen Vižintin, Jan Bitenc, Jernej Bobnar, Iztok Arčon, Anna Randon-Vitanova, Robert Dominko, 2020, izvirni znanstveni članek Opis: Development of magnesium sulfur battery is accompanied with all known difficulties present in Li–S batteries,
however with even more limited choice of electrolytes. In the present work, the influence of current collector on
electrochemical mechanism was investigated in light of different reports where improved behavior was ascribed
to electrolyte. Notable differences in cycling behavior are reported when Al current collector is replaced by Cu
current collector independent of electrolyte. The initial reduction of sulfur follows similar reaction path no mater
of current collector, but formation of MgS can be in competition with formation of CuS in the presence of Cu
cations. With the subsequent cycling cells prepared from cathodes deposited on Cu current collector show
decrease in the voltage and formation of single plateau during cycling. The change corresponds to the
involvement of Cu into the reaction and formation of redox couple Mg/CuS as determined by Cu K-edge XANES
measurements. Corrosion of Cu foil is identified by SEM and serves as a source of Cu cations for the chemical
reaction between Cu and polysulfides. Mg/CuS redox couple shows improved cycling stability, but theoretical
energy density is severely reduced due to substitution of S with CuS as cathode active material.
Ključne besede: Magnesium
Sulfur
Rechargeable batteries
Current collector
Copper
Corrosion
Objavljeno: 16.01.2020; Ogledov: 8; Prenosov: 0
 Polno besedilo (1,86 MB) |
4. Arabidopsis halleri shows hyperbioindicator behaviour for Pb and leaf Pb accumulation spatially separated from ZnStephan Höreth, Paula Pongrac, Marta Debeljak, Katarina Vogel-Mikuš, Matic Pečovnik, Primož Vavpetič, Iztok Arčon, izvirni znanstveni članek Opis: Lead (Pb) ranks among the most problematic environmental pollutants. Background contamination of soils is nearly ubiquitous, yet plant Pb accumulation is barely understood. In a survey covering 165 European populations of the metallophyte Arabidopsis halleri, several field samples had indicated Pb hyperaccumulation, offering a chance to dissect plant Pb accumulation.
Accumulation of Pb was analysed in A. halleri individuals from contrasting habitats under controlled conditions to rule out aerial deposition as a source of apparent Pb accumulation. Several elemental imaging techniques were employed to study the spatial distribution and ligand environment of Pb.
Regardless of genetic background, A. halleri individuals showed higher shoot Pb accumulation than A. thaliana. However, dose–response curves revealed indicator rather than hyperaccumulator behaviour. Xylem sap data and elemental imaging unequivocally demonstrated the in planta mobility of Pb. Highest Pb concentrations were found in epidermal and vascular tissues. Distribution of Pb was distinct from that of the hyperaccumulated metal zinc. Most Pb was bound by oxygen ligands in bidentate coordination.
A. halleri accumulates Pb whenever soil conditions render Pb phytoavailable. Considerable Pb accumulation under such circumstances, even in leaves of A. thaliana, strongly suggests that Pb can enter food webs and may pose a food safety risk.
Ključne besede: Pb accumulation, XANES, EXAFS, Arabidopsis halleri
Objavljeno: 16.01.2020; Ogledov: 8; Prenosov: 0
Polno besedilo (4,46 MB) |
5. Mineral element composition in grain of awned and awnletted wheat (Triticum aestivum L.) cultivars tissue-specific iron speciation and phytate and non-phytate ligand ratioHiram Castillo Michel, Iztok Arčon, Paula Pongrac, Katarina Vogel-Mikuš, 2020, izvirni znanstveni članek Opis: In wheat (Triticum aestivum L.), the awns—the bristle-like structures extending from
lemmas—are photosynthetically active. Compared to awned cultivars, awnletted cultivars produce
more grains per unit area and per spike, resulting in significant reduction in grain size, but their
mineral element composition remains unstudied. Nine awned and 11 awnletted cultivars were
grown simultaneously in the field. With no di erence in 1000-grain weight, a larger calcium and
manganese—but smaller iron (Fe) concentrations—were found in whole grain of awned than in
awnletted cultivars. Micro X-ray absorption near edge structure analysis of di erent tissues of
frozen-hydrated grain cross-sections revealed that di erences in total Fe concentration were not
accompanied by di erences in Fe speciation (64% of Fe existed as ferric and 36% as ferrous species) or
Fe ligands (53% were phytate and 47% were non-phytate ligands). In contrast, there was a distinct
tissue-specificity with pericarp containing the largest proportion (86%) of ferric species and nucellar
projection (49%) the smallest. Phytate ligand was predominant in aleurone, scutellum and embryo
(72%, 70%, and 56%, respectively), while nucellar projection and pericarp contained only non-phytate
ligands. Assuming Fe bioavailability depends on Fe ligands, we conclude that Fe bioavailability from
wheat grain is tissue specific.
Ključne besede: biofortification, phytate, iron, awn, X-ray fluorescence, X-ray absorption spectrometry, phosphorus, sulphur, nicotianamine
Objavljeno: 16.01.2020; Ogledov: 6; Prenosov: 0
Polno besedilo (2,63 MB) |
6. The Circular Economy in Adaptive Reuse: Respecting Authenticity and IntegrityJukka Jokilehto, Saša Dobričić, Marco Acri, 2019, objavljeni znanstveni prispevek na konferenci Opis: One of the main topics of discussion and research at present in the building sector is related to the principles of circular economy in a new global scenario of resilience and sustainability. Given that most of European urban areas and landscapes are considered as cultural, it derives that the circular economy should be also applied to the actions and processes of conservation and valorisation, giving thus new emphasis on the concept of adaptive reuse. Thus, it is not merely an issue of retrofitting historic buildings to respond to energy efficiency parameters, or to adapt them for the climate change threats, but much more: it is about rethinking adaptive reuse of cultural heritage (adaptive in both directions) within and overall sustainable process which intakes reflections on materials, techniques, technologies, praxes, but also policies, businesses, management and governance. This is the effort of the CLIC project, Circular Models leveraging investments in Cultural heritage adaptive reuse, in the Horizon2020 research framework, where the University of Nova Gorica is a partner.
This new approach in a global market economy perspective is strongly looking backwards to the traditional building site mechanisms, techniques and procedures, as matured in logistic and technological constraints. In history though, prior of the enforcing of the conservation theory principles, the aspects of authenticity and integrity were not a reference for the builders as the materials and the technologies were usual, repetitive for centuries, while today they are essential criteria for conservation and reuse. But what does it mean today looking at circular models in adaptive reuse? Adaptive reuse refers to the need to adapt cultural heritage to new needs and uses, but circularity ask also to adapt to the cultural heritage peculiarities and fragilities. May this mean we have an additional ally for the preservation of the integrity and the authenticity, as well as for a new wave in preservation of objects, urban and cultural landscapes?
Ključne besede: Circular Economy, Heritage Adaptive Reuse, Conservation Theory, Authenticity and Integrity of Cultural Heritage, Historic Urban Landscape
Objavljeno: 16.01.2020; Ogledov: 8; Prenosov: 0
Polno besedilo (1,82 MB) |
7. Elucidation of Donor:Acceptor Phase Separation in Nonfullerene Organic Solar Cells and Its Implications on Device Performance and Charge Carrier MobilitySebastian F. Hoefler, Georg Haberfehlner, Thomas Rath, Andreas Keilbach, Mathias Hobisch, Alexander Dixon, Egon Pavlica, Gvido Bratina, Gerald Kothleitner, Ferdinand Hofer, Gregor Trimmel, 2019, izvirni znanstveni članek Opis: In bulk-heterojunction solar cells, the device performance strongly depends on the donor and acceptor properties, the phase separation in the absorber layer, and the formation of a bicontinuous network. While this phase separation is well explored for polymer:fullerene solar cells, only little is known for polymer:nonfullerene acceptor solar cells. The main hurdle in this regard is often the chemical similarity of the conjugated polymer donor and the organic nonfullerene acceptor (NFA), which makes the analysis of the phase separation via atomic force microscopic (AFM) phase images or conventional transmission electron microscopy difficult. In this work, we use the donor polymer PTB7-Th and the small molecule acceptor O-IDTBR as the model system and visualized the phase separation in PTB7-Th:O-IDTBR bulk-heterojunctions with different donor:acceptor ratios via scanning transmission electron microscopy (STEM) high-angle annular dark-field (HAADF) images and electron energy loss spectroscopy (EELS) based elemental mapping, which resulted in a good contrast between the donor and the acceptor despite very low differences in the chemical composition. AFM as well as grazing-incidence wide-angle X-ray scattering (GIWAXS) investigations support the electron microscopic data. Furthermore, we elucidate the implications of the phase separation on the device performance as well as charge carrier mobilities in the bulk-heterojunction layers, and a high performance of the solar cells was found over a relatively broad range of polymer domain sizes. This can be related to the larger domain sizes of the acceptor phase with higher amounts of O-IDTBR in the blend, while the polymer donor phase still forms continuous pathways to the electrode, which keeps the hole mobility at a relatively constant level.
Ključne besede: nanomorphology bulk-heterojunction scanning transmission electron microscopy organic photovoltaics charge carrier mobility
Objavljeno: 15.01.2020; Ogledov: 6; Prenosov: 1
Polno besedilo (6,22 MB) |
8. Quality Control of Purified Proteins to Improve Research Data ReproducibilityStephan Uebel, Ario de Marco, Nick Berrow, Mario Lebendiker, Maria Garcia-Alai, Stefan Knauer, Blanca Lopez-Mendez, Andrea Matagne, Annabel Parret, Kim Remans, Bertrand Raynal, 2019, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje) Ključne besede: protein quality, biophysical analysis, aggregation
Objavljeno: 15.01.2020; Ogledov: 23; Prenosov: 0
Polno besedilo (432,57 KB) |
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