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(1998) Yoon, Yong; Pope, J; Wolfe, JosephJournal Article
Freezing-Induced Hydration Forces Between Phospatidylcholine Bilayers-The Effect of Osmotic Pressure(1997) Wolfe, Joseph; Yoon, Yong; Pope, JJournal ArticleQuantitative nuclear magnetic resonance was used to measure the freezing behaviour of lamellar phases of phosphatidylcholine in water and in solutions of sorbitol. Both solute and solvent were deuterated in different series of experiments to allow the calculation of the partitioning of solute and solvent molecules between the lamellar phase and unfrozen bulk solution. Sorbitol, as well as water, was found to redistribute between these phases as a function of temperature. The results show a strong, repulsive, interlamellar force which decreases approximately exponentially with hydration. Compared to measurements on lipid/water systems and solute/water systems, the hydration of the lamellar phase containing solutes is slightly less than the sum of the hydrations of lipid and solute at any given chemical potential of water. For a lamellar phase with a given quantity of lipid, interlamellar sorbitol and water, reduction of chemical potential of water is greater than that due to lipid acting alone plus that due to solute acting alone.
The Effects of Firing Conditions on the Properties of Electrophoretically Deposited Titanium Dioxide Films on Graphite Substrates(2011) Hanaor, Dorian; Michelazzi, Marco; Chenu, Jeremy; Leonelli, Cristina; Sorrell, CharlesJournal ArticleThick anatase films were fabricated on graphite substrates using a method of anodic aqueous electrophoretic-deposition using oxalic acid as a dispersant. Thick films were subsequently fired in air and in nitrogen at a range of temperatures. The morphology and phase composition were assessed and the photocatalytic performance was examined by the inactivation of Escherichia coli in water. It was found that the transformation of anatase to rutile is enhanced by the presence of a graphite substrate through reduction effects. The use of a nitrogen atmosphere allows higher firing temperatures, results in less cracking of the films and yields superior bactericidal performance in comparison with firing in air. The beneficial effects of a nitrogen firing atmosphere on the photocatalytic performance of the material are likely to be a result of the diffusion of nitrogen and carbon into the TiO2 lattice and the consequent creation of new valence band states.
Changes in fire regimes since the Last Glacial Maximum: an assessment based on a global synthesis and analysis of charcoal data(2008) Power, M; Marlon, J; Ortiz, N; Bartlein, P; Harrison, Simon; Mayle, F; Ballouche, A; Bradshaw, R; Carcaillet, C; Cordova, C; Mooney, Scott; Moreno, P; Prentice, I; Thonicke, K; Tinner, W; Whitlock, C; Zhang, Yanling; Zhao, Yong; Ali, Amna; Anderson, Richard; Beer, R; Behling, H; Briles, C; Brown, Katherine; Brunelle, A; Bush, M; Camill, P; Chu, G; Clark, J; Colombaroli, D; Connor, Stuart; Daniau, A; Daniels, M; Dodson, John; Doughty, E; Edwards, Meredith; Finsinger, W; Foster, Douglas; Frechette, J; Gaillard, M; Gavin, D; Gobet, E; Haberle, Simon; Hallett, D; Higuera, P; Hope, G; Horn, S; Inoue, J; Kaltenrieder, P; Kennedy, Liz; Kong, Z; Larsen, C; Long, C; Lynch, Jodi; Lynch, E; McGlone, M; Meeks, S; Mensing, S; Meyer, G; Minckley, T; Mohr, J; Nelson, D; New, J; Newnham, R; Noti, R; Oswald, W; Pierce, J; Richard, P; Rowe, C; Goni, M; Shuman, B; Takahara, H; Toney, J; Turney, C; Urrego-Sanchez, D; Umbanhowar, C; Vandergoes, M; Vanniere, B; Vescovi, EJournal ArticleFire activity has varied globally and continuously since the last glacial maximum (LGM) in response to long-term changes in global climate and shorter-term regional changes in climate, vegetation, and human land use. We have synthesized sedimentary charcoal records of biomass burning since the LGM and present global maps showing changes in fire activity for time slices during the past 21,000 years (as differences in charcoal accumulation values compared to pre-industrial). There is strong broad-scale coherence in fire activity after the LGM, but spatial heterogeneity in the signals increases thereafter. In North America, Europe and southern South America, charcoal records indicate less-than-present fire activity during the deglacial period, from 21,000 to ∼11,000 cal yr BP. In contrast, the tropical latitudes of South America and Africa show greater-than-present fire activity from ∼19,000 to ∼17,000 cal yr BP and most sites from Indochina and Australia show greater-than-present fire activity from 16,000 to ∼13,000 cal yr BP. Many sites indicate greater-than-present or near-present activity during the Holocene with the exception of eastern North America and eastern Asia from 8,000 to ∼3,000 cal yr BP, Indonesia and Australia from 11,000 to 4,000 cal yr BP, and southern South America from 6,000 to 3,000 cal yr BP where fire activity was less than present. Regional coherence in the patterns of change in fire activity was evident throughout the post-glacial period. These complex patterns can largely be explained in terms of large-scale climate controls modulated by local changes in vegetation and fuel load.
(1995) Atchison, S; Burford, Robert; Whitby, C; Hibbert, D. BrynnJournal Article