98 research outputs found
A new intersecting tunnel structure in the AIMIII[PO3(OH)]2 series for AI = Ag, MIII = In : Analysis of structural relationships.
A new indium hydroxyphosphate containing silver, AgIn[PO3(OH)]2, has been synthesized using hydrothermal method. It crystallizes in the P21/c space group with the cell parameters a = 6.6400(2)Å, b=14.6269(6)Å, c=6.6616(4)A, β=95.681(5)°, V=643.82(6)Å3, Z=4. Its three-dimensional framework, built up of comer-sharing PO3(OH) tetrahedra and InO6 octahedra, presents intersecting tunnels running along and [100] directions, in which the Ag+ cations are located. The presence of hydroxyl groups has been confirmed from IR spectroscopy studies and hydrogen atoms were located from the single crystal X-ray diffraction study. The structural relationships with the other compounds of general formula AΙΜΙΙΙ[PΟ3(OH)]2 are analyz
Welfare issues and potential solutions for laying hens in free range and organic production systems: A review based on literature and interviews
In free-range and organic production systems, hens can make choices according to their needs and desires, which is in accordance with welfare definitions. Nonetheless, health and behavioral problems are also encountered in these systems. The aim of this article was to identify welfare challenges observed in these production systems in the EU and the most promising solutions to overcome these challenges. It is based on a review of published literature and research projects complemented by interviews with experts. We selected EU specific information for welfare problems, however, the selected literature regarding solutions is global. Free range use may increase the risk of infection by some bacteria, viruses and parasites. Preventive methods include avoiding contamination thanks to biosecurity measures and strengthening animals' natural defenses against these diseases which can be based on nutritional means with new diet components such as insect-derived products, probiotics and prebiotics. Phytotherapy and aromatherapy can be used as preventive and curative medicine and vaccines as alternatives to antibiotics and pesticides. Bone quality in pullets and hens prevents keel deviations and is favored by exercise in the outdoor range. Free range use also lead to higher exposure to variable weather conditions and predators, therefore shadow, fences and guard animals can be used to prevent heat stress and predation respectively. Granting a free range provides opportunities for the expression of many behaviors and yet many hens usually stay close to the house. Providing the birds with trees, shelters or attractive plants can increase range use. Small flock sizes, early experiences of enrichment and personality traits have also been found to enhance range use. Severe feather pecking can occur in free range production systems, although flocks using the outdoor area have better plumage than indoors. While many prevention strategies are facilitated in free range systems, the influence of genetics, prenatal and nutritional factors in free range hens still need to be investigated. This review provides information about practices that have been tested or still need to be explored and this information can be used by stakeholders and researchers to help them evaluate the applicability of these solutions for welfare improvement
Nouveaux phosphates d élément trivalent (synthèses, déterminations structurales et caractérisations physico-chimiques)
CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF
Synthèse, caractérisations structurales et physico-chimiques de nouveaux phosphates d'éléments de transition
Cette thèse porte sur l étude de phosphates d éléments de transition, dont les structures à charpentes mixtes comportent des cavités ou des feuillets pouvant accueillir des cations en insertion. La richesse structurale rencontrée au sein de cette famille de composés ouvre la voie à de nombreuses propriétés. Nous avons orienté nos recherches vers l étude de systèmes A-M-P-O(-H) où A est un cation monovalent et M un élément de transition (si possible en valence mixte), ou de post transition dans le but d obtenir de nouveaux matériaux en vue d application en catalyse. Dans ce cadre, l étude des systèmes A-M-P-O(-H) avec A = NH4, Li, Na, K, Rb, Cs et M = Fe, Mn et In a été entreprise. Un autre objectif de ce travail était de mieux comprendre l influence des conditions expérimentales d une synthèse sur la nature des phases formées. Malgré la difficulté d obtenir des nouveaux matériaux au sein des systèmes considérés, nous avons pu isoler onze nouvelles phases dont trois présentent une charpente originale. Les déterminations structurales ont été effectuées par diffraction des RX sur monocristal combinée à des études par diffraction des RX sur poudre et à des analyses EDS. L étude des propriétés catalytiques pour une réaction de DeNOx via la NH3-SCR a été réalisée par spectroscopie IR in situ et operando couplée à la spectrométrie de masse pour un des phosphates de fer synthétisés. Les propriétés magnétiques de quatre des composés présentés dans ce manuscrit sont discutées.This thesis deals with the study of transition element phosphates, whose mixed frameworks contain cavities able to host cations. The great structural wealth in this family of compounds opens the way to numerous properties. We have chosen to study A-M-P-O(-H) systems in which A is a monovalent cation and M is a transition element (mixed-valent if possible) or post transition element, in order to obtain new materials for catalytic applications. In this context, the study of the A-M-P-O(-H) systems, with A = NH4, Li, Na, K, Rb, Cs and M = Fe, Mn and In has been undertaken. The other aim of this work was a better understanding of the influence of synthesis experimental conditions on the nature of the obtained phases. In spite of the difficulty to synthesize new materials in the considered systems, eleven new phases have been isolated and three of them exhibit original framework. Structural determinations have been performed by single crystal X-ray diffraction combined with powder X-ray diffraction and EDX analysis. The study of catalytic properties for DeNOx reaction via the NH3-SCR have been carried out by in situ and operando spectroscopy and mass spectroscopy for one iron phosphate. Magnetic properties of four compounds, which are reported in this manuscript, are discussed.CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF
La problématique du sujet dans les récits autobiographiques de Blaise Cendrars
CAEN-BU Droit Lettres (141182101) / SudocSudocFranceF
Vocabulaire codicologique arabe
Vocabulaire codicologique arabe permettant de décrire des manuscrits et d'accéder à leur traduction en plusieurs languesThe Arabic codicological vocabulary is part of Codicologia (CNRS-IRHT) which is composed of three databases. Codicologia provides a multilingual vocabulary for the description of manuscripts. It aims to provide a working tool for all manuscript cataloguers, text editors and more generally for all those interested in ancient manuscripts.Le vocabulaire codicologique arabe fait partie de Codicologia (CNRS-IRHT) qui est une application informatique composée de trois bases de données. Codicologia fournit un vocabulaire multilingue pour la description des manuscrits. Elle entend proposer un instrument de travail à tous les catalogueurs de manuscrits, les éditeurs de textes et plus généralement à tous ceux qui s'intéressent aux manuscrits anciens
A new intersecting tunnel structure in the AIMIII[PO3(OH)]2 series for AI = Ag, MIII = In : Analysis of structural relationships.
International audienceA new indium hydroxyphosphate containing silver, AgIn[PO3(OH)]2, has been synthesized using hydrothermal method. It crystallizes in the P21/c space group with the cell parameters a = 6.6400(2)Å, b=14.6269(6)Å, c=6.6616(4)A, β=95.681(5)°, V=643.82(6)Å3, Z=4. Its three-dimensional framework, built up of comer-sharing PO3(OH) tetrahedra and InO6 octahedra, presents intersecting tunnels running along and [100] directions, in which the Ag+ cations are located. The presence of hydroxyl groups has been confirmed from IR spectroscopy studies and hydrogen atoms were located from the single crystal X-ray diffraction study. The structural relationships with the other compounds of general formula AΙΜΙΙΙ[PΟ3(OH)]2 are analyz
Topochemical Approach for Transition-Metal Exchange Assisted by Copper Extrusion from Cu2FeBO5 to Fe3BO5
International audienceAll fields of today's technology are concerned with multifunctional materials, the subject of constantly expanding research. Among them, metal transition oxides occupy a strategic place because of the properties directly correlated with metal valence linked with oxygen stoichiometry. To enhance or induce new properties, knowledge of the relationships between the structural and physical characteristics is of prime importance, but a design at low scale also appears to be a powerful tool to increase the chemical reactivity and stabilize new compounds. Herein, an unexpected reaction is reported that associates the exchange of copper and iron in a 3D ludwigite lattice with the huge release of oxygen (14% by weight) at moderate temperature (<450 degrees C). Annealing of Cu2FeBO5 in a reducing atmosphere leads to the extrusion of copper and the formation of Fe3BO5, the micro/nanostructural state of which facilitates the partial Cu2FeBO5 recovery associated with the capture of oxygen in oxidizing conditions
Topochemical Approach for Transition-Metal Exchange Assisted by Copper Extrusion from Cu2FeBO5 to Fe3BO5
All fields of today's technology are concerned with multifunctional materials, the subject of constantly expanding research. Among them, metal transition oxides occupy a strategic place because of the properties directly correlated with metal valence linked with oxygen stoichiometry. To enhance or induce new properties, knowledge of the relationships between the structural and physical characteristics is of prime importance, but a design at low scale also appears to be a powerful tool to increase the chemical reactivity and stabilize new compounds. Herein, an unexpected reaction is reported that associates the exchange of copper and iron in a 3D ludwigite lattice with the huge release of oxygen (14% by weight) at moderate temperature (<450 degrees C). Annealing of Cu2FeBO5 in a reducing atmosphere leads to the extrusion of copper and the formation of Fe3BO5, the micro/nanostructural state of which facilitates the partial Cu2FeBO5 recovery associated with the capture of oxygen in oxidizing conditions
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