Mechanism of carbon dioxide and water incorporation in Ba2TiO4: A joint computational and experimental study

© 2017 American Chemical Society. CO 2 incorporation in solids is attracting considerable interest in a range of energy-related areas. Materials degradation through CO 2 incorporation is also a critical problem with some fuel cell materials, particularly for proton conducting ceramic fuel cells. Despite this importance, the fundamental understanding of the mechanism of CO 2 incorporation is lacking. Furthermore, the growing use of lower temperature sol gel routes for the design and synthesis of new functional materials may be unwittingly introducing significant residual carbonate and hydroxyl ions into the material, and so studies such as the one reported here investigating the incorporation of carbonate and hydroxyl ions are important, to help explain how this may affect the structure and properties. This study on Ba 2 TiO 4 suggests highly unfavorable intrinsic defect formation energies but comparatively low H 2 O and CO 2 incorporation energies, in accord with experimental findings. Carbonate defects are likely to form in both pristine and undoped Ba 2 TiO 4 systems, whereas those based on H 2 O will only form in systems containing other supporting defects, such as oxygen interstitials or vacancies. However, both hydroxyl and carbonate defects will trap oxide ion defects induced through doping, and the results from both experimental and modeling studies suggest that it is primarily the presence of carbonate that is responsible for stabilizing the high temperature α′-phase at lower temperatures

Studies on the Colonia isolate of Physarum polycephalum.

Physarum polycephalum is a Myxomycete or true slime mould, the life cycle of which alternates between two growing phases; amoebae and plasmodia. Strains of the Colonia isolate of Physarum polycephalum form plasmodia within single clones of amoebae; this is in contrast to strains of other isolates which require the sexual fusion of two amoebae of different mating type for plasmodium formation to occur. The mode of plasmodium formation by Colonia strains enables them to be used for the isolation of mutant plasmodia after anoebal mutagenssis and direct sereening of plasmodia. This thesis reports the derivation of a Colonia strain, CL, (Colonia Leicester) for mutant isolation purposes together with the construction of isogenic strains of heterothallic mating type. These strains have been used to isolate and genetically analyse strains carrying auxotrophic mutations which can only be tested for in the plasmodial stage. Attempts have also been made to devise selective techniques for the isolation of strains carrying specific classes of mutation, in particular a strain deficient in thymidylate synthetase activity. A series of investigations employing microdensitometric estimation of nuclear DNA content, time-lapse microcinematography and genetic methods has indicated that plasmodium formation by Colonia amoebae is probably apogamous and not homothallic as was previously reported by other workers

Photochemistry of [Ru(pytz)(btz)₂]²⁺ and Characterization of a κ¹‑btz Ligand-Loss Intermediate

We report the synthesis, characterization, and photochemical reactivity of the triazole-containing complex [Ru­(pytz)­(btz)₂]²⁺ (<b>1</b>, pytz = 1-benzyl-4-(pyrid-2-yl)-1,2,3-triazole, btz = 1,1′-dibenzyl-4,4′-bi-1,2,3-triazolyl). The UV–vis absorption spectrum of <b>1</b> exhibits pytz- and btz-centered ¹MLCT bands at 365 and 300 nm, respectively. Upon photoexcitation, acetonitrile solutions of <b>1</b> undergo conversion to the ligand-loss intermediate, <i>trans</i>-[Ru­(pytz)­(κ²-btz)­(κ¹-btz)­(NCMe)]²⁺ (<b>2</b>, Φ₃₆₃ = 0.013) and ultimately to the ligand-loss product <i>trans</i>-[Ru­(pytz)­(btz)­(NCMe)₂]²⁺ (<b>3</b>), both of which are observed and characterized by ¹H NMR spectroscopy. Time-dependent density functional theory calculations reveal that the S₁ state of the complex has primarily HOMO → LUMO pytz-based ¹MLCT character. Data show that the ³MLCT and ³MC states are in close energetic proximity (≤0.11 eV to 2 d.p.) and that the T₁ state from a single-point triplet state calculation at the S₀ geometry suggests ³MC character. Optimization of the T₁ state of the complex starting from the ground state geometry leads to elongation of the two Ru–N­(btz) bonds <i>cis</i> to the pytz ligand to 2.539 and 2.544 Å leading to a pseudo-4-coordinate ³MC state rather than the ³MLCT state. The work therefore provides additional insights into the photophysical and photochemical properties of ruthenium triazole-containing complexes and their excited state dynamics

Confirmatory factor analysis of CAPP dimensions deleting items for best fit.

<p>Confirmatory factor analysis of CAPP dimensions deleting items for best fit.</p

Correlations among CAPP total and domain scores for the whole sample.

<p>Correlations among CAPP total and domain scores for the whole sample.</p

Distribution of CAPP total, domains and items.

<p>Cronbach’s alpha calculated without the specified variable.</p

IPDE scores, sociodemographic and forensic variables of the sample.

<p>Levels of significance for these variables in relation to an arbitrary CAPP cut-off score of 76 (the sample mean) are also included.</p

Fully Standardized Factor Loadings for Bi-Factor EFA Model.

<p>Fully Standardized Factor Loadings for Bi-Factor EFA Model.</p

Reliability indexes from Classical Test Theory: CAPP total and dimension scores.

<p>Reliability indexes from Classical Test Theory: CAPP total and dimension scores.</p

Confirmatory factor analysis of CAPP dimensions with all items.

<p>Confirmatory factor analysis of CAPP dimensions with all items.</p