Modeling of granular solids with computational homogenization: Comparison with Biot's theory

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Highly Unsaturated Binuclear Butadiene Iron Carbonyls: Quintet Spin States, Perpendicular Structures, Agostic Hydrogen Atoms, and Iron-Iron Multiple Bonds

The highly unsaturated binuclear butadiene iron carbonyls (C4H6)2Fe2(CO)n (n = 2, 1) have been examined using density functional theory. For (C4H6)2Fe2(CO)n (n = 2, 1), both coaxial and perpendicular structures are found. The global minima of (C4H6)2Fe2(CO)n (n = 2, 1) are the perpendicular structures 2Q-1 and 1Q-1, respectively, with 17- and 15-electron configurations for the iron atoms leading to quintet spin states. The Fe=Fe distance of 2.361 Å (M06-L) in the (C4H6)2Fe2(CO)2 structure 2Q-1 suggests a formal double bond. The Fe≡Fe bond distance in the (C4H6)2Fe2(CO) structure 1Q-1 is even shorter at 2.273 Å (M06-L), suggesting a triple bond. Higher energy (C4H6)2Fe2(CO)n (n = 2, 1) structures include structures in which a bridging butadiene ligand is bonded to one of the iron atoms as a tetrahapto ligand and to the other iron atom through two agostic hydrogen atoms from the end CH2 groups. Singlet (C4H6)2Fe2(CO) structures with formal Fe–Fe quadruple bonds of lengths ∼2.05 Å were also found but at very high energies (∼47 kcal/mol) relative to the global minimum

Insight into the mechanism of decarbonylation of methanol by ruthenium complexes; a deuterium labelling study

The authors thank Lucite international for funding.In the reaction of [RuHClP3] (P = PPh3) with NaOMe in methanol, the product is [RuH2(CO)P3]. Short reaction times show that the final product is formed through [RuH4P3] as the major intermediate. Using NaOCD3 in CD3OD, the first formed product is [RuH4P'3] (P' is PPh3 partially deuterated in the ortho positions of the aromatic rings). Further reaction leads to a mixture of [RuHnD2-n(CO)P3] (n = 0, 22 %; n = 1, 2 isomers each 28 %; n = 2, 22 %). Mechanistic aspects of both steps of the reaction are explored and, together with previously published calculations, they provide definitive mechanisms for both dehydrogenation and decarbonylation in these interesting systems.PostprintPeer reviewe

The Elite and Popular Foundations of German Catholicism in the Age of Confessionalism: The Reichskirche.

The political, institutional, and religious particularism of the German church reinforced the loyalty of the population, to local religious traditions. This gave German Catholicism a local emphasis and hindered the imposition of reformed Catholicism, which sought to homogenize, centralize, and internationalize the church. While early modern German Catholicism was certainly conservative, it was not rigidly traditional. Religious change occurred in these centuries and it came out of the interaction between the local population, local institutions like the chapters and monasteries, the parish clergy, and reforming churchmen.[70] The role of chapters and monasteries was not insignificant in this process. Canons and monks, whose daily lives were taken up with religious practices that owed much more to medieval Christian traditions than to the reforms of the Council of Trent, undoubtedly sympathized with and participated in the religion of the people. In the context of the Holy Roman Empire, manyGerman church institutions fought to preserve their own particular privileges and traditions, which gave them little inclination to destroy the local religion of their subjects. Localism and particularism thus became a valued hallmark of German Catholicism, as much among the Catholic elite as among the people. [ABSTRACT FROM AUTHOR

Hydromechanical modelling of an initial boundary value problem: Studies of non-uniqueness with a second gradient continuum

A non-uniqueness study for a hydromechanical boundary value problem is performed. A fully saturated porous medium is considered using an elasto-plastic constitutive equations to describe the mechanical behavior of the skeleton. A real hydromechanical experiment which consists in a hollow cylinder test on a Boom Clay sample is modelled. It is shown that the time step discretisation of the numerical problem has an effect on the initialisation of the Newton-Raphson algorithm on a given time step. Different solutions for the same initial boundary value problem can consequently be found

Local second gradient models for thermo-hydro-mechanical coupling in rock like materials

In the design of nuclear waste disposals, an important topic concerns the evolution of an Excavated Damage Zone (EDZ) with a thermal exchanges. In this paper, a new model of local second gradient coupling with a thermo-hydro-mechanical is presented. As for monophasic case, the use of enhanced media induce the objective of the computation but not the uniqueness of the solution. Some classical engineering problems are presented which exhibit several solutions

Hydromechanical modeling of an initial boundary value problem: Studies of non-uniqueness with a second gradient continuum

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