647 research outputs found

    Preparation, performances and reaction mechanism for the synthesis of H2O2 from H2 and O2 based on palladium membranes

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    Taking a critically informed approach, this innovative text examines emerging approaches to social procurement within the context of New Public Government (NPG), and examines the practices of social procurement across Europe, North America and Australia. Considering both the possibilities and limitations of social procurement, and the types of value it can generate, this book also provides empirically driven insights into the practicalities of 'triple bottom line' procurement, the related challenges of measuring social value and the management of both the strategic and operational dimensions of procurement processes. As such it will be invaluable reading for all those interest in social services, public governance and social enterprise

    The role of charge-matching in nanoporous materials formation

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    Unravelling the molecular-level mechanisms that lead to the formation of mesoscale-ordered porous materials is a crucial step towards the goal of computational material design. For silica templated by alkylamine surfactants, a mechanism based on hydrogen-bond interactions between neutral amines and neutral silicates in solution has been widely accepted by the materials science community, despite the lack of conclusive evidence to support it. We demonstrate, through a combination of experimental measurements and multi-scale modelling, that the so-called “neutral templating route” does not represent a viable description of the synthesis mechanism of hexagonal mesoporous silica (HMS), the earliest example of amine-templated porous silica. Instead, the mesoscale structure of the material is defined by charge-matching of ionic interactions between amines and silicates. This has profound implications for the synthesis of a wide range of templated porous materials, and may shed new light on developing sustainable and economical routes to high value porous materials

    Catalysis on nano-carbon materials: Going where to?

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    This introductory contribution to the special issue of Catalysis Today is dedicated to selected contributions presented at the Carbocat-IV (Carbon for Catalysis) Symposium held in Dalian (China) on November 7–10 (2010). The introduction first shortly overviews the main reasons for the interest on carbon materials for catalysis and the elements of novelty discussed on the contributions of this issue, and then provide a concise outline of the general trends and developments in this field to give a glimpse on the progresses in the field, and on the perspectives of this exciting area of catalysis

    The Bacteriostatic Activity of 2-Phenylethanol Derivatives Correlates with Membrane Binding Affinity

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    The hydrophobic tails of aliphatic primary alcohols do insert into the hydrophobic core of a lipid bilayer. Thereby, they disrupt hydrophobic interactions between the lipid molecules, resulting in a decreased lipid order, i.e., an increased membrane fluidity. While aromatic alcohols, such as 2-phenylethanol, also insert into lipid bilayers and disturb the membrane organization, the impact of aromatic alcohols on the structure of biological membranes, as well as the potential physiological implication of membrane incorporation has only been studied to a limited extent. Although diverse targets are discussed to be causing the bacteriostatic and bactericidal activity of 2-phenylethanol, it is clear that 2-phenylethanol severely affects the structure of biomembranes, which has been linked to its bacteriostatic activity. Yet, in fungi some 2-phenylethanol derivatives are also produced, some of which appear to also have bacteriostatic activities. We showed that the 2-phenylethanol derivatives phenylacetic acid, phenyllactic acid, and methyl phenylacetate, but not Tyrosol, were fully incorporated into model membranes and affected the membrane organization. Furthermore, we observed that the propensity of the herein-analyzed molecules to partition into biomembranes positively correlated with their respective bacteriostatic activity, which clearly linked the bacteriotoxic activity of the substances to biomembranes

    Use of Pt/CexZr1-xAl2O3 as Advanced Catalyst for Hydrogen Peroxide Thrusters

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    The capability of different Pt/Ce0.6Zr0.4/Al2O3 catalytic systems of effectively decomposing H2O2 has been studied in view of their application to monopropellant thrusters. BET surface area measurements, X-Ray Diffractometry (XRD) and Scanning Electron Microscopy (SEM) have been used together with catalytic tests in order to evaluate the advantages of using CeO2-ZrO2 mixed oxide solid solution as an alternative to current three ways catalysts (TWCs). From the assessment of alternative solutions, a Pt/Ce0.6Zr0.4/Al2O3 catalyst suitable to effectively decompose H2O2 has been identified. SEM-EDX analyses ruled out the occurrence of phase segregation and selective deposition of Pt on Zr during the catalyst preparation. No changes in the crystalline arrangement of the catalyst samples after H2O2 decomposition have been detected by XRD measurements, except for a slight crystallization or grain size growth as a consequence of the high temperatures experienced during the reaction...
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