Royal Society

Résumé

La Royal Society, dont le nom officiel est Royal Society of London for the Improvement of Natural Knowledge et que l'on peut traduire littéralement par « Société royale de Londres pour l'amélioration des connaissances naturelles », est une institution fondée en 1660 siégeant au Carlton House Terrace à Londres et destinée à la promotion des sciences. Cette société savante est l’équivalent de l’Académie des sciences en France. La Royal Irish Academy, fondée en 1782, lui est affiliée. La Royal Society of Edinburgh, fondée en 1783, est une institution écossaise indépendante. Membres renommés Membre de la Royal Society De très nombreux savants ont contribué à la création et à l'essor de la Royal Society. Elle compte parmi les membres fondateurs Robert Boyle, John Evelyn, Robert Hooke, William Petty, John Wallis, John Wilkins, Thomas Willis, Jean Chardin, Elias Ashmole et Christopher Wren. Isaac Newton y présenta sa théorie de l’optique, et en devint plus tard le président. Pa

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Numerical Ecology with R provides a long-awaited bridge between a textbook in Numerical Ecology and the implementation of this discipline in the R language. After short theoretical overviews, the authors accompany the users through the exploration of the methods by means of applied and extensively commented examples. Users are invited to use this book as a teaching companion at the computer. The travel starts with exploratory approaches, proceeds with the construction of association matrices, then addresses three families of methods: clustering, unconstrained and canonical ordination, and spatial analysis. All the necessary data files, the scripts used in the chapters, as well as the extra R functions and packages written by the authors, can be downloaded from a web page accessible through the Springer web site(http://adn.biol.umontreal.ca/~numericalecology/numecolR/). This book is aimed at professional researchers, practitioners, graduate students and teachers in ecology, environmental science and engineering, and in related fields such as oceanography, molecular ecology, agriculture and soil science, who already have a background in general and multivariate statistics and wish to apply this knowledge to their data using the R language, as well as people willing to accompany their disciplinary learning with practical applications. People from other fields (e.g. geology, geography, paleoecology, phylogenetics, anthropology, the social and education sciences, etc.) may also benefit from the materials presented in this book. The three authors teach numerical ecology, both theoretical and practical, to a wide array of audiences, in regular courses in their Universities and in short courses given around the world. Daniel Borcard is lecturer of Biostatistics and Ecology and researcher in Numerical Ecology at Université de Montréal, Québec, Canada. François Gillet is professor of Community Ecology and Ecological Modelling at Université de Franche-Comté, Besançon, France. Pierre Legendre is professor of Quantitative Biology and Ecology at Université de Montréal, Fellow of the Royal Society of Canada, and ISI Highly Cited Researcher in Ecology/Environment.

Springer2011

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Producing concentrated solutions of monosaccharides using biphasic CO2–H2O mixtures

Yuan Li, Jeremy Luterbacher

Sustainably producing concentrated solutions of monosaccharides from biomass is a key challenge facing the conversion of lignocellulosic biomass to biofuels or bioproducts. Most pretreatment and enzymatic hydrolysis processes are run at low-solid concentration (<10 wt%) and use chemical catalysts, while most high-solids enzymatic hydrolysis experiments are performed with air-dried pretreated materials. Using optimally two-temperature stage CO 2-H2O pretreated biomass substrates (210 °C 16 min, 160°C, 60 min for mixed hardwood and 210°C, 1 min, 160°C, 60 min), high-solids enzymatic hydrolysis reactions were performed in a novel high-solids reaction system. With this system, twelve "rotating drum" reactors were run simultaneously in a controlled environment. Without additional chemical catalysts or any drying, two-temperature stage CO2-H2O pretreatment coupled with high-solids enzymatic hydrolysis produced monosaccharide solutions of 185 g L-1 for mixed hardwood and 149 g L-1 for switchgrass. Apart from results obtained with dilute acid pretreated corn stover, these are the most concentrated solutions obtained from biomass pretreatment and enzymatic hydrolysis without substrate drying. The corresponding glucan to glucose yields were above 80% for both types of biomass. Notably, these high yields were obtained because, similar to dilute acid pretreatment but unlike un-catalyzed pretreatment, our approach produced biomass that did not show decreasing yields with increasing enzymatic hydrolysis solid contents. These results suggest that CO2-H2O pretreatment is an attractive alternative to chemically catalyzed processes such as dilute acid pretreatment. © 2012 The Royal Society of Chemistry.

2012

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Mobility and dynamics in the complex hydrides LiAlH4 and LiBH4

Pascal Martelli

The dynamics and bonding of the complex hydrides LiBH4 and LiAlH4 have been investigated by vibrational spectroscopy. The combination of infrared, Raman, and inelastic neutron scattering (INS) spectroscopies on hydrided and deuterided samples reveals a complete picture of the dynamics of the BH-4 and AlH-4 anions respectively as well as the lattice. The straightforward interpretation of isotope effects facilitates tracer diffusion experiments revealing the diffusion coefficients of hydrogen containing species in LiBH4, and LiAlH4. LiBH4 exchanges atomic hydrogen starting at 200 °C. Despite having an iso-electronic structure, the mobility of hydrogen in LiAlH4 is different from that of LiBH4. Upon ball-milling of LiAlH4 and LiAlD4, hydrogen is exchanged with deuterium even at room temperature. However, the exchange reaction competes with the decomposition of the compound. The diffusion coefficients of the alanate and borohydride have been found to be D ≃ 7 × 10-14 m2 s -1 at 473 K and D ≃ 5 × 10-16 m2 s-1 at 348 K, respectively. The BH-4 ion is easily exchanged by other ions such as I- or by NH-2. This opens the possibility of tailoring physical properties such as the temperature of the phase transition linked to the Li-ion conductivity in LiBH4 as measured by nuclear magnetic resonance and Raman spectroscopy. Temperature dependent Raman measurements on diffusion gradient samples Li(BH4)1-cIc demonstrate that increasing temperature has a similar impact to increasing the iodide concentration c: the system is driven towards the high-temperature phase of LiBH4. The influence of anion exchange on the hydrogen sorption properties is limited, though. For example, Li4(BH 4)(NH2)3 does not exchange hydrogen easily even in the melt. © The Royal Society of Chemistry 2011.

2011

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Springer2011