2,250 research outputs found

    Ionic liquids and reactions at the electrochemical interface

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    Ionic liquids (ILs) represent a fascinating, and yet to be fully understood, medium for a variety of chemical, physical and biological processes. Electrochemical processes form an important subset of these that are particularly of interest, since ILs tend to be good electrochemical solvents and exhibit other properties which make them very useful as electrolytes in electrochemical devices. It is important therefore to understand the extent to which electrochemical reactions and processes behave in a relatively &ldquo;normal&rdquo;, for example aqueous solution, fashion as opposed to exhibiting phenomena more uniquely the product of their organic ionic nature. This perspective examines a range of electrochemical reactions in ionic liquids, in many cases in the context of real world applications, to highlight the phenomena as far as they are understood and where data gaps exist. The important areas of lithium and conducting polymer electrochemistry are discussed in detail.<br /

    Organic ionic plastic crystals : recent advances

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    Investigations into the synthesis and utilisation of organic ionic plastic crystals have made significant progress in recent years, driven by a continued need for high conductivity solid state electrolytes for a range of electrochemical devices. There are a number of different aspects to research in this area; fundamental studies, utilising a wide range of analytical techniques, of both pure and doped plastic crystals, and the development of plastic crystal-based materials as electrolytes in, for example, lithium ion batteries. Progress in these areas is highlighted and the development of new organic ionic plastic crystals, including a new class of proton conductors, is discussed.<br /

    An Ultrastructural Analysis of the Physical Organization of Collagenous (Type I) Matrices: One Determinant of Urothelium Maintenance In Vitro

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    Collagenous matrices, used as cell culture substrata, can be prepared from different collagen types in a variety of forms using a range of polymerization procedures. Type I collagen has been most frequently used either as dried collagen films or hydrated collagen gels. Sheets of isolated bladder urothelium, when plated onto such matrices prepared from type I collagen by different polymerization methods (eg. air-drying; NaOH; NaCl; NH3; or NH3 followed by glutaraldehyde crosslinking) demonstrate the capability of urothelial cells to attach to a variety of differently prepared matrices irrespective of polymerization procedure. In contrast, both cell proliferation and maintenance of the urothelium are markedly influenced by the polymerized form of the collagen matrix. Comparative ultrastructural (scanning and transmission electron microscopy) analysis of these matrices demonstrates dissimilarities in their physical organization. The level of filamentous, fibrillar or fibrous reaggregation of solubilized collagen molecules varies in relation to the polymerization procedure used viz, a) air dried matrices form a dense meshwork of many forms of collagen fibrils and associated filaments with an irregular surface array of coarser collagen fibres; b) matrices prepared by NaOH, NaCl and NH3 polymerization present no major differences and form a felt of interlocking collagen fibres with discrete filamentous networks associated with these fibres; and c) matrices polymerized by NH3 and crosslinked with glutaraldehyde form a dense meshwork of filaments with a more occasional distribution of fibrils associated with filaments or dense amorphous aggregates. The level of supramolecular reassemblage of solubilized collagen may be, therefore, a significant factor in determining urothelial cell growth and differentiation on collagen matrices

    N-methyl-N-alkylpyrrolidinium nonafluoro-1-butanesulfonate salts : Ionic liquid properties and plastic crystal behaviour

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    A series of N-methyl-N-alkylpyrrolidinium nonafluoro-1-butanesulfonate salts were synthesised and characterised. The thermophysical characteristics of this family of salts have been investigated with respect to potential use as ionic liquids and solid electrolytes. N-Methyl-N-butylpyrrolidinium nonafluoro-1-butanesulfonate (p1,4NfO) has the lowest melting point of the family, at 94 &deg;C. Electrochemical analysis of p1,4 NfO in the liquid state shows an electrochemical window of ~6 V. All compounds exhibit one or more solid&ndash;solid transitions at sub-ambient temperatures, indicating the existence of plastic crystal phases.<br /

    Categorification of a linear algebra identity and factorization of Serre functors

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    We provide a categorical interpretation of a well-known identity from linear algebra as an isomorphism of certain functors between triangulated categories arising from finite dimensional algebras. As a consequence, we deduce that the Serre functor of a finite dimensional triangular algebra A has always a lift, up to shift, to a product of suitably defined reflection functors in the category of perfect complexes over the trivial extension algebra of A.Comment: 18 pages; Minor changes, references added, new Section 2.

    Ionic liquids and organic ionic plastic crystals utilizing small phosphonium cations

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    The development of new liquid and solid state electrolytes is paramount for the advancement of electrochemical devices such as lithium batteries and solar cells. Ionic liquids have shown great promise in both these applications. Here we demonstrate the use of phosphonium cations with small alkyl chain substituents, in combination with a range of different anions, to produce a variety of new halide free ionic liquids that are fluid, conductive and with sufficient thermal stability for a range of electrochemical applications. Walden plot analysis of the new phosphonium ionic liquids shows that these can be classed as &quot;good&quot; ionic liquids, with low degrees of ion pairing and/or aggregation, and the lithium deposition and stripping from one of these ionic liquids has been demonstrated. Furthermore, for the first time phosphonium cations have been used to form a range of organic ionic plastic crystals. These materials can show significant ionic conductivity in the solid state and thus are of great interest as potential solid-state electrolyte materials. <br /

    Orchard Day, August 18, 1955; Results of Fruit Research

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    Storing peaches / Donald Comin -- Trends in storages / Donald Comin -- Grape varieties ; Grape soil management and fertilization ; Nitrogen fertilizers for apple trees / J. M. Beattie -- Colorset on Golden Delicious and Grimes ; Planting distance influence on yield of apples ; Harvest dates for apples ; Summer varieties of apples ; Pre-harvest spraying for Baldwin / C. W. Ellenwood -- Peach investigations ; The blueberry planting ; Strawberry studies ; Plum varieties and culture ; Grape weed control studies / R. G. Hill, Jr. -- Semi-dwarf apple trees in Ohio / Freeman S. Howlett and T. E. Fowler -- The Franklin Apple / Freeman S. Howlett and C. W. Ellenwood -- Status of intermediate (trunk-forming) stocks for the apple ; Pruning the newly planted apple tree ; Status of the pear industry in Ohio / Freeman S. Howlett -- Pear variety collection indicates several deserve limited trial / Freeman S. Howlett and C. W. Ellenwoo

    Using legume-based mixtures to enhance the nitrogen use efficiency and economic viability of cropping systems - Final report (LK09106/HGCA3447)

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    As costs for mineral fertilisers rise, legume-based leys are recognised as a potential alternative nitrogen source for crops. Here we demonstrate that including species-rich legume-based leys in rotations helps to maximise synergies between agricultural productivity and other ecosystem services. By using functionally diverse plant species mixtures, these services can be optimised and fine-tuned to regional and farm-specific needs. Replicated field experiments were conducted over three years at multiple locations, testing the performance of 12 legume species and 4 grass species sown in monocultures, as well as in a mixture of 10 of the legumes and all 4 grasses (called the All Species Mix, ASM). In addition, we compared this complex mixture to farmer-chosen ley mixtures on 34 sites across the UK. The trials showed that there is a large degree of functional complementarity among the legume species. No single species scored high on all evaluation criteria. In particular, the currently most frequently used species, white clover, is outscored by other legume species on a number of parameters such as early development and resistance to decomposition. Further complementarity emerged from the different responses of legume species to environmental variables, with soil pH and grazing or cutting regime being among the more important factors. For example, while large birdsfoot trefoil showed better performance on more acidic soils, the opposite was true for sainfoin, lucerne and black medic. In comparison with the monocultures, the ASM showed increased ground cover, increased above-ground biomass and reduced weed biomass. Benefits of mixing species with regard to productivity increased over time. In addition, the stability of biomass production across sites was greater in the ASM than in the legume monocultures. Within the on-farm trials, we further found that on soils low in organic matter the biomass advantage of the ASM over the Control ley was more marked than on the soils with higher organic matter content. Ecological modelling revealed that the three best multifunctional mixtures all contained black medic, lucerne and red clover. Within the long term New Farming Systems (NFS) rotational study, the use of a clover bi-crop showed improvement to soil characteristics compared to current practice (e.g. bulk density and water infiltration rate). Improvements in wheat yield were also noted with respect to the inclusion of a clover bi-crop in 2010, but there was evidence of a decline in response as the N dose was increased. Cumulatively, over both the wheat crop and the spring oilseed rape crop, the clover bi-crop improved margin over N. The highest average yield response (~9%) was associated with the ASM legume species mix cover cropping approach
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