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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 259-264 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Bipolar membranes consist of a layered ion-exchange structure composed of a cation selective membrane joined to an anion selective membrane. They are analogous to semiconductor p-n devices as both of them present current-voltage curves exhibiting similar rectification properties. In this article, we present some current-voltage curves obtained for different bipolar membranes at several temperatures. The results can be interpreted in terms of a simple model for ion transport and field-enhanced water dissociation previously developed. The mechanism responsible for water splitting is assumed to be a catalytic proton transfer reaction between the charged groups and the water at the membrane interface. The effects of temperature are taken into account by introducing an Arrhenius-type relationship for the dependence of the forward rate constant of the reaction on temperature. Finally, comparison between theory and experiments provides reasonable values for the parameters introduced in the theoretical model. The analysis aims at developing a better physical understanding of a process in which chemical reactions and transport phenomena are coupled in such a way that the potential technological applications depend strongly on this coupling.
    Type of Medium: Electronic Resource
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  • 2
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    PANGAEA
    In:  Supplement to: Chavez, Veronica; Geyer, J; Reichle, S; Gerold, Gerhard; Ibisch, P L (submitted): Is Conservation Action Planning (CAP) adapting to climate change? related article: JEMA-S-12-02880; data submission at http://issues.pangaea.de/browse/PDI-3514, Environmental Management
    Publication Date: 2020-01-18
    Description: It is widely recognized that climate change poses significant challenges to the conservation of biodiversity. The need of dealing with relatively rapid and uncertain environmental change calls for the enhancement of adaptive capacity of both biodiversity and conservation management systems. Under the hypothesis that most of the conventional biodiversity conservation tools do not sufficiently stimulate a dynamic protected area management, which takes rapid environmental change into account, we evaluated almost 900 of The Nature Conservancy's site-based conservation action plans. These were elaborated before a so-called climate clinic in 2009, an intensive revision of existing plans and a climate change training of the planning teams. We also compare these results with plans elaborated after the climate clinic. Before 2009, 20% of the CAPs employed the term “climate change” in their description of the site viability, and 45% identified key ecological attributes that are related to climate. 8% of the conservation strategies were directly or indirectly related to climate change adaptation. After 2009, a significantly higher percentage of plans took climate change into account. Our data show that many planning teams face difficulties in integrating climate change in their management and planning. However, technical guidance and concrete training can facilitate management teams learning processes. Arising new tools of adaptive conservation management that explicitly incorporate options for handling future scenarios, vulnerability analyses and risk management into the management process have the potential of further making protected area management more proactive and robust against change.
    Type: Dataset
    Format: application/pdf, 74.0 kBytes
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  • 3
    ISSN: 0887-624X
    Keywords: poly(ethersulfone) ; Udel® ; lithiation ; sulfination ; sulfonic acid ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new process has been developed for the sulfonation of arylene polymers which can be lithiated, like polysulfone Udel®. The sulfonation process consists of the following steps: (1) lithiation of the polymer at temperatures from -50 to -80°C under argon, (2) gassing of the lithiated polymer with SO2; (3) oxidation of the formed polymeric sulfinate with H2O2, NaOCl, or KMnO4; (4) ion-exchange of the lithium salt of the sulfonic acid in aqueous HCl. The advantages of the presented sulfonation procedure are: (1) in principle all polymers which can be lithiated can be subjected to this sulfonation process; (2) by this sulfonation procedure the sulfonic acid group is inserted into the more hydrolysis-stable part of the molecule; (3) this process is ecologically less harmful than many common sulfonation procedures. The sulfonated polymers were characterized by NMR, titration and elemental analysis, by IR spectroscopy, and by determination of ionic conductivity. Also the hydrolytic stability of the sulfonated ion-exchange polymers was investigated. Polymers with an ion-exchange capacity of 0.5 to 3.2 mequiv SO3H/g Polymer have been synthesized and characterized. The following results have been achieved: membranes made from the sulfonated polymers show good conductivity, good permselectivity (〉90%), and good hydrolytic stability in 1N HCl and water at temperatures up to 80°C. © 1996 John Wiley & Sons, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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