11 research outputs found
Thermal and Chemical Expansion in Proton Ceramic Electrolytes and Compatible Electrodes
No full textThis review paper focuses on the phenomenon of thermochemical expansion of two specific categories of conducting ceramics: Proton Conducting Ceramics (PCC) and Mixed Ionic-Electronic Conductors (MIEC). The theory of thermal expansion of ceramics is underlined from microscopic to macroscopic points of view while the chemical expansion is explained based on crystallography and defect chemistry. Modelling methods are used to predict the thermochemical expansion of PCCs and MIECs with two examples: hydration of barium zirconate (BaZr1−xYxO3−δ) and oxidation/reduction of La1−xSrxCo0.2Fe0.8O3−δ. While it is unusual for a review paper, we conducted experiments to evaluate the influence of the heating rate in determining expansion coefficients experimentally. This was motivated by the discrepancy of some values in literature. The conclusions are that the heating rate has little to no effect on the obtained values. Models for the expansion coefficients of a composite material are presented and include the effect of porosity. A set of data comprising thermal and chemical expansion coefficients has been gathered from the literature and presented here divided into two groups: protonic electrolytes and mixed ionic-electronic conductors. Finally, the methods of mitigation of the thermal mismatch problem are discussed
Aphaenogaster jolantae Borowiec & Salata, 2014, sp. nov.
No full textAphaenogaster jolantae sp. nov. Etymology. Dedicated to Jolanta Świetojańska, associate and participant in all myrmecological trips of the senior author and a well-known Polish entomologist. Type material. Holotype worker: GREECE, Rhodes | Epta Piges 92 m, W of | Kolymbia, 36 ° 15 ’N / 28 °06’E | 4 VII 2008, L. Borowiec || Collection L. Borowiec | Formicidae | LBC-GR00109 (BMNH); 23 paratype workers: the same data as holotype (DBET, SMNG, CASC, MLBC); 4 paratype workers: GREECE, Rhodes | Apollona, 36 ° 15 ’N / 27 ° 55 ’E | 10 VII 2008, 287 m | L. Borowiec || Collection L. Borowiec | Formicidae | LBC-GR00163 (DBET). Description. Measurements: Workers (n= 11): HL: 1.342 ± 0.078 (1.117–1.420); HW: 0.888 ± 0.093 (0.704–1.016); TL: 0.621 ± 0.04 (0.536–0.693); GL: 0.482 ± 0.03 (0.425–0.52); NW: 0.482 ± 0.031 (0.441–0.536); CW: 0.173 ± 0.019 (0.131–0.201); FLW: 0.307 ± 0.027 (0.257–0.346); SL: 1.686 ± 0.085 (1.457–1.763); EL: 0.246 ± 0.012 (0.218–0.257); EW: 0.186 ± 0.016 (0.145–0.201); ML: 1.928 ± 0.118 (1.605–2.092); PSL: 0.241 ± 0.027 (0.179–0.279); SDL: 0.197 ± 0.017 (0.168–0.235); HTL: 1.529 ± 0.096 (1.280–1.661); PL: 0.538 ± 0.040 (0.487–0.575); PPL: 0.377 ± 0.03 (0.324–0.419); PH: 0.32 ± 0.029 (0.279–0.357); PPH: 0.306 ± 0.028 (0.251–0.351); PNW: 0.658 ± 0.043 (0.553–0.704); DPSB: 0.223 ± 0.025 (0.167–0.246); DPST: 0.246 ± 0.038 (0.207–0.313); PW: 0.232 ± 0.018 (0.187–0.251); PPW: 0.287 ± 0.024 (0.234–0.335); CI: 66.1 ± 5.1 (52–71.8); CL: 19.5 ± 1.9 (17.8–24.4); FLI: 56.4 ± 6.1 (50–72.8); SI 1: 125.7 ± 2.7 (122.3–130.4); F 2: 191.6 ± 19.6 (171–246); PI 1: 167.9 ± 16.9 (149.6–204.3); PI 2: 61.5 ± 7.1 (53.4–77); PPI 1: 123.3 ± 7.5 (109.7–133.9); PPI 2: 35.7 ± 3.4 (33.1–43.6); SPI 1: 27.3 ± 3.3 (24.6–34.9); SPI 2: 122.2 ± 7.6 (106.5–129.5); HTI: 173.5 ± 16.1 (158.9–217.6) MI: 293.4 ± 11.1 (271.2–312.1); PSI: 142.4 ± 12.4 (127.2–162.2); TGI: 129.1 ± 9.4 (115.4–144.4). Head, thorax and abdomen pale brown, first abdominal tergite without paler basal spot. Legs mostly brown only tarsi yellowish to yellowish-brown, often trochanters, knee and apices of tibiae paler colored, yellowishbrown. Antennal scapes brown, pedicle yellowish brown (Figs. 5, 6). Head posterior to eyes gently, regularly convex, without constriction at base, basal margin margined by sharp carina (Fig. 24). Anterior margin of clypeus shallowly emarginate. Eyes small, 0.41 times as long as length of tempora. Scapes elongate and slim, 1.68 times as long as width of head, at base 0.58 times as wide as in apex, gradually widened, mostly straight, only apex slightly bent down without preapical constriction. Funicle elongate and thin, 1.38–1.40 times as long as scape, first segment elongate, 2.8 times as long as wide on apex, 1.29 times as long as second segment, length ratio of segments 100: 77: 95: 95: 95: 91: 95: 127: 118: 127: 200, apical segments 1.75 times as wide as basal segments (Fig. 17). Surface of scape finely microreticulate but shiny, covered with short and sparse adherent setae and only at apex of scape pubescence slightly raised from the ground. Promesonotum 1.77 times as long as wide, pronotum gently, regularly convex in profile without cleft between pronotum and mesonotum. Propodeum elongate, 1.29 times as long as wide, propodeal spines short, needle-like, runs obliquely upwards (Fig. 6). Petiole elongate with long peduncle, its anterior face deeply concave, node from subangulate to rounded in profile. Posterior face straight in anterior 3 / 4 length then shallowly concave. Ventral margin of petiole straight, without spine or distinct angulation (Fig. 6). In dorsal view, petiole almost parallel sided anterior to petiolar node, then gently widened. Postpetiole in profile regularly rounded. In dorsal view postpetiole 1.33 times as long as wide, regularly widened from base to apex, apical half with gently rounded sides (Fig. 5). Mandibles elongate, with outer edges straight, dorsal surface with distinct striation and several setose punctures, shiny, inner margin with one larger and 6–7 smaller teeth. Clypeus on whole surface with fine longitudinal rugae, interspaces microreticulate but shiny. Frontal carinae short, not extending to the line connecting anterior margin of eyes, subparallel, interantennal area deeply impressed, shiny, with only one median, fine carina, frontal triangle with very thin longitudinal rugae appearing as striation, microreticulate but shiny. Frons only on sides with thin longitudinal rugae, in central part with distinct microsculpture but shiny. Area between eyes distinctly microreticulate but appears shiny, microreticulation gradually diffused from front to back, gena, tempora and base of head with indistinct sculpture, on vertex microreticulation mostly diffused and surface shiny. Pronotum with microreticulation diffused on top, distinct on sides. Top of pronotum shiny, sides more or less shiny, with rows of 4 + 1 + 2 setae. Mesonotum on whole surface microreticulate and partly microgranulate, sides microgranulate without rugae or only with 2–3 short, transverse rugae, propodeum at top microreticulate, on sides with slightly granulate sculpture, below spiracles with few fine longitudinal rugae, top in anterior part with fine transverse wrinkles but surface of both mesonotum and propodeum appears slightly shiny (Fig. 5). Top of mesosoma in anterior part with 6 setae, in posterior part with only 2 setae, propodeum anteriorly with a pair of short setae, as long as or slightly shorter than propodeal spines. Base of petiole and postpetiole microreticulate but without wrinkles, nodes smooth and shiny, covered with several sparse, long setae. Gaster shiny, first tergite at base without longitudinal grooves and without distinct microreticulation (Fig. 13), tergites with sparse, long, erect setae from as long as to 1.5 times as long as propodeal spines. Legs very long, hind femora 1.04 times as long as thorax, hind tibiae 0.77 times as long as hind femora, hind tarsi 1.23 times as long as hind femora. Dorsal surface of femora with short, sparse, adherent pubescence, inner margin with row of sparse, moderately long, setae, tibiae on whole surface covered with very short, adherent pubescence, only inner, apical margins with row or slightly longer and semierect setae (Fig. 6). Biology. A nest of this species was located in a crevice inside a shallow cavern, near the middle of a 3 m high wall of a gorge on the famous tourist route Epta Piges (Seven Springs). Workers were foraging on the inner wall of the cavern at a distance of 1 m from the entrance to the nest. A couple of the foragers were carrying remains of moths collected from a nearby spider web. More workers were found in a hollow trunk of a huge Platanus orientalis tree. A large entrance to the hollow tree was located about 70 cm above the ground and led to a hollow trunk that could accommodate two standing people standing. The interior walls of the tree were charred; the entrance to the nest was probably on the roof of the hollow, where a few foraging workers were collected. Distribution. Greece, Dodecanese, Rhodes island. Discussion. Aphaenogaster jolantae sp. nov., Aphaenogaster olympica sp. nov. and Aphaenogaster equestris sp. nov. are together easily distinguished from the other three species of the A. cecconii group by the head lacking a narrowed neck with flared collar. Aphaenogaster equestris differs in having the body mostly rusty-yellow and the sculpture of the head stronger, with the head surface partly dull. Aphaenogaster olympica is very similar and differs in subtle morphometric and sculptural characters described in the key.Published as part of Borowiec, Lech & Salata, Sebastian, 2014, Review of Mediterranean members of the Aphaenogaster cecconii group (Hymenoptera: Formicidae), with description of four new species in Zootaxa 3861 (1), DOI: 10.11646/zootaxa.3861.1.2, http://zenodo.org/record/22839
Democracy and Human Rights in the European-Asian Dialogue: A Clash of Cooperation Cultures?
No full textWhereas the European Union (EU) favors a formal, binding, output-oriented, and to some extent supranational approach to cooperation, the Association of Southeast Asian Nations (ASEAN) is based on informal, non-binding, process-oriented intergovernmental forms of cooperation. This article addresses the question of whether these differences between European and Asian cooperation norms or cultures can account for interregional cooperation problems in the areas of democracy and human rights within the institutional context of EU-ASEAN and the Asia-Europe Meeting (ASEM). The author argues that a clash of cooperation cultures basically occurs in both forms of interregional collaboration between Asia and Europe, with slight differences due to the institutional context: while disagreements over the question of democracy and human rights between the EU and ASEAN have led to a temporary and then a complete standstill in cooperation, the flexible institutional mechanisms of ASEM seem, at first glance, to mitigate the disruptive effects of such dialogues. Yet informality does not remove the issues from the agenda, as the recurrent disputes over Myanmar’s participation and the nonintervention norm favored by the Asian side of ASEM clearly indicate. Antagonistic cooperation cultures thus play a significant role in explaining the obstructive nature of the interregional human rights and democracy dialogue between Asia and Europe.cooperation culture, human rights, democracy, Myanmar, EU-ASEAN, ASEM
Electrochemical performance of Co3O4/CeO2 electrodes in H2S/H2O atmospheres in a proton-conducting ceramic symmetrical cell with BaZr0.7Ce0.2Y0.1O3 solid electrolyte
No full textThe electrochemical performance of Co3O4/CeO2 mixed oxide materials as electrodes, when exposed to H2S/H2O atmospheres, was examined employing a proton conducting symmetrical cell, with BaZr0.7Ce0.2Y0.1O3 (BZCY72) as the solid electrolyte. The impact of temperature (700–850 °C) and H2S concentration (0–1 v/v%) in steam-rich atmospheres (90 v/v% H2O) on the overall cell performance was thoroughly assessed by means of electrochemical impedance spectroscopy (EIS) studies. The performance of the Co3O4/CeO2 electrode was significantly enhanced by increasing the H2S concentration and temperature. The obtained results were interpreted on the basis of EIS results and physicochemical characterization (XRD, SEM) studies of fresh and used electrodes. Notably, it was found that the mass transport processes, mainly associated with the adsorption and diffusion of the intermediate species resulting by the chemical and half-cell reactions taking place during cell operation, dominate the electrode polarization resistance compared with the charge transfer processes. Upon increasing temperature and H2S concentration, the electrode resistance is substantially lowered, due to the in situ activation and morphological modifications of the electrode, induced by its interaction with the reactants (H2S/H2O) and products (H2/SO2) mixtures
Additive manufacturing of Proton-Conducting Ceramics by robocasting with integrated laser postprocessing
No full text[EN] A hybrid system combining robocasting and NIR laser postprocessing has been designed to fabricate layers of mixed proton-electron conducting Ba0.5La0.5Co1-xFexO3-delta ceramic. The proposed manufacturing technique allows for the control of the geometry and microstructure and shortens the fabrication time to a range of a few minutes. Using 5 W laser power and a scanning speed of 500 mms(-1), sintering of a round-shaped layer with an 8 mm radius was performed in less than 2 s. The single phase of the final product was confirmed by X-ray diffraction. Various ceramic-to-polymer weight ratios were tested, showing that various porosities of microstructures of similar to 30 - 35 % and similar to 19 % can be obtained with 2:1 and 4:1 loading respectively.The project FunKeyCat is supported by the National Science Centre, Poland under the M-ERA.NET 2, which has received funding from the European Union's Horizon 2020 research and innovation program under Grant Agreement No 685451, from the Research Council of Norway (Grant n degrees 299736) , and the Spanish Government (M-ERA.NET PCI2019-103742) . The authors also express gratitude to Piotr Okoczuk, MSc Eng, for performing the confocal microscopy measurements and to Robert Tylingo, Ph.D., D.Sc. Eng., for conducting the viscosity measurements and for their contribution to this work.Pospiech, J.; Nadolska, M.; Cieslik, M.; Sobczyk, T.; Chmielewski, M.; Mielewczyk-Gryn, A.; Strandbakke, R.... (2024). Additive manufacturing of Proton-Conducting Ceramics by robocasting with integrated laser postprocessing. Applied Materials Today. 40. https://doi.org/10.1016/j.apmt.2024.102398S4
Physicochemical properties of La0.5Ba0.5Co1-xFexO3-δ (0 ≤ x ≤ 1) as positrode for proton ceramic electrochemical cells
No full textWe report on essential properties of materials in the series La0.5Ba0.5Co1-xFexO3-δ as positrodes for proton ceramic electrochemical cells (PCECs). The unit cell and thermochemical expansion coefficient (TCEC) of these cubic perovskites decrease with iron content x, the TCEC of La0.5Ba0.5FeO3-δ going as low as 11⋅10-6 1/K. The materials behave as LaMO3 perovskites with small band gaps and Ba acting as acceptors compensated by electron holes and oxygen vacancies. The electrical properties are dominated by p-type conduction with high large polaron mo- bilities for the Co-rich compositions at low temperatures, shifting towards small polaron mobilities with increasing Fe content. X-ray absorption spectroscopy (XAS) shows that Co is in a high spin state and takes on the main part of the cation oxidation state changes, and that hole states are in orbitals overlapping with the O 2p states, confirming the large polaronic behaviour, while holes on Fe are more localised at the cation. Hydration is more pronounced in inert atmospheres, as hydration of oxygen vacancies is easier than hydrogenation and in- creases with Fe content, in line with the commonly accepted finding that delocalization of holes disfavours protonation. Fe-rich compositions benefit from lower TCEC and higher hydration and hence expected proton permeability, at the cost of lower electronic conductivity. The surfaces are hydrophobic irrespective of Fe content, suggesting weak chemisorption of the underlaying water layer, possibly giving relatively many available surface sites for oxygen adsorption, but limited surface proton conductance – both of importance to positrodes for operando PCECspublishedVersio
The “Ants of Cyprus” website: a dynamic, online awareness raising and conservation tool
No full textAnts are an important arthropod group due to their involvement in ecological processes amongst others as ecosystem engineers or predators, but some invasive alien species are also implicated in detrimental environmental, economic and human health effects. Despite recent advancements, the ant biodiversity of Cyprus is still in need of further research with previous online species inventories synthesising a checklist of just 65 native and 10 alien species. The “Ants of Cyprus” website (https://sites.google.com/view/ ants-of-cyprus) aims to: (1) raise public awareness and increase local knowledge on the biodiversity and ecological significance of ants, (2) provide ecological data and (3) enhance conservation efforts and management practices for native and alien ant species, respectively. This dynamic, user-friendly website has been designed for use by the scientific community, conservation officers and the wider public and it will be regularly updated as new information and data are generated. Additionally, this information will be critical for reporting on progress towards biodiversity targets and goals. © Demetriou J et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
High-Temperature Structural and Electrical Properties of BaLnCo2O6 Positrodes
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Structural properties of mixed conductor Ba1−xGd1−yLax+yCo2O6−δ
No full textBa1−xGd1−yLax+yCo2O6−δ (BGLC) compositions with large compositional ranges of Ba, Gd, and La have been characterised with respect to phase compositions, structure, and thermal and chemical expansion. The results show a system with large compositional flexibility, enabling tuning of functional properties and thermal and chemical expansion. We show anisotropic chemical expansion and detailed refinements of emerging phases as La is substituted for Ba and Gd. The dominating phase is the double perovskite structure Pmmm, which is A-site ordered along the c-axes and with O vacancy ordering along the b-axis in the Ln-layer. Phases emerging when substituting La for Ba are orthorhombic Ba-deficient Pbnm and cubic LaCoO3-based R[3 with combining macron]c. When La is almost completely substituted for Gd, the material can be stabilised in Pmmm, or cubic Pm[3 with combining macron]m, depending on thermal and atmospheric history. We list thermal expansion coefficients for x = 0–0.3, y = 0.2.publishedVersio
Structure and water uptake in BaLnCo2O6−δ (Ln = La, Pr, Nd, Sm, Gd, Tb and Dy)
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