174,441 research outputs found
C. Bankaert et al., Naissance de l'ethnologie ? Anthropologie et missions en Amérique, XVIe-XVIIIe siècle
No full textBucher Bernadette. C. Bankaert et al., Naissance de l'ethnologie ? Anthropologie et missions en Amérique, XVIe-XVIIIe siècle. In: L'Homme, 1988, tome 28 n°106-107. Le mythe et ses métamorphoses. pp. 346-347
C−H Insertion of Aurated Aryl Cations
No full textFunding Information: J. Bucher is grateful for a Chemiefonds scholarship of the Fonds der Chemischen Industrie. The authors thank Umicore AG & Co. KG for the generous donation of gold salts. Publisher Copyright: © 2023 The Authors. Advanced Synthesis & Catalysis published by Wiley-VCH GmbH.By employing the sterically highly demanding steering ligand IPr* at a gold(I) center, it is possible to induce a 6-endo-dig cyclization pathway in 1,5-diynes bearing terminal alkyne moieties. The resulting aurated naphthyl cations are utilized for the intermolecular formation of C−C bonds via C−H insertion of aromatic and aliphatic C−H bonds. The mechanisms of these transformations were studied by quantum chemical calculations.Peer reviewe
Ideal and physical barrier problems for non-linear systems driven by normal and Poissonian white noise via path integral method
No full textIn this paper, the probability density evolution of Markov processes is analyzed for a class of barrier problems specified in terms of certain boundary conditions. The standard case of computing the probability density of the response is associated with natural boundary conditions, and the first passage problem is associated with absorbing boundaries. In contrast, herein we consider the more general case of partially reflecting boundaries and the effect of these boundaries on the probability density of the response. In fact, both standard cases can be considered special cases of the general problem. We provide solutions by means of the path integral method for half- and single-degree-of-freedom systems for both normal and Poissonian white noise. Emphasis is put on the considerations of the yielding barrier which is expressed in terms of non-reflecting (but not absorbing) boundary conditions. Comparison with Monte Carlo simulation demonstrates the excellent accuracy of the proposed method
Dynamic Finite Element analysis of fractionally damped structural systems in the time domain
No full textVisco-elastic material models with fractional characteristics have been used for several decades.
This paper provides a simple methodology for Finite-Element-based dynamic analysis of structural systems with viscosity characterized by fractional derivatives of the strains. In particular, a re-formulation of the wellknown Newmark method taking into account fractional derivatives discretized via the Grünwald–Letnikov summation allows the analysis of structural systems using standard Finite Element technology
Innovative straight formulation for plate in bending
No full textIn this paper it has been introduced an innovative formulation for evaluating the deflection function of a simply supported plate loaded by uniformly distributed edge moments. Framed into Line Element-less Method, this formulation allows the evaluation of solution in terms of deflection, through few lines of algorithm implemented by Mathematica software without resorting to any discretization neither in the domain nor in the boundary. Interesting savings in terms of time and computational costs are achieved. Results obtained by the proposed method are well contrasted by ones obtained by classical methods and Finite Element Method
Efficient solution of the first passage problem by Path Integration for normal and Poissonian white noise
No full textIn this paper the first passage problem is examined for linear and nonlinear systems driven by Poissonian and normal white noise input. The problem is handled step-by-step accounting for the Markov properties of the response process and then by Chapman-Kolmogorov equation. The final formulation consists just of a sequence of matrix-vector multiplications giving the reliability density function at any time instant. Comparison with Monte Carlo simulation reveals the excellent accuracy of the proposed method
The Italian journal of geosciences is increasing its appeal among geoscientists
No full textThis is an Editorial of the new Editorial Board of the Italian Journal of Geosciences, composed by Marco Balini (Milan), Hugo Bucher (Zürich), Simonetta Cirilli (Perugia), Laura Crispini (Genoa), Maurizio Mazzucchelli (Modena), and Giulio Ottonello (Genoa), which underlines the progress in the appeal of the journal among Geoscientists
On the block wavelet transform applied to the boundary element method
No full textThis paper follows an earlier work by Bucher et al. [1] on the application of wavelet transforms to the boundary element method, which shows how to reuse models stored in compressed form to solve new models with the same geometry but arbitrary load cases - the so-called virtual assembly technique. The extension presented in this paper involves a new computational procedure created to perform the required two-dimensional wavelet transforms by blocks, theoretically allowing the compression of matrices of arbitrary size. Details of the computer implementation that allows the use of this methodology for very large models or at high compression ratios are given. A numerical application shows a standard PC being used to solve a 131,072 DOF model, previously compressed, for 100 distinct load cases in less than 1 hour – or 33 seconds for each load case
A quantitative version of a theorem by Jungreis
No full textA fundamental result by Gromov and Thurston asserts that, if M is a closed hyperbolic n-manifold, then the simplicial volume |M| of M is equal to vol(M)/v_n, where v_n is a constant depending only on the dimension of M. The same result also holds for complete finite-volume hyperbolic manifolds without boundary, while Jungreis proved that the ratio vol(M)/|M| is strictly smaller than v_n if M is compact with non-empty geodesic boundary. We prove here a quantitative version of Jungreis' result for n>3, which bounds from below the ratio |M|/vol(M) in terms of the ratio between the volume of the boundary of M and the volume of M. As a consequence, we show that a sequence {M_i} of compact hyperbolic n-manifolds with geodesic boundary is such that the limit of vol(M_i)/|M_i| equals v_n if and only if the volume of the boundary of M_i grows sublinearly with respect to the volume of the boundary of M_i. We also provide estimates of the simplicial volume of hyperbolic manifolds with geodesic boundary in dimension three
Dem Ruf der Sirenen widerstehen lernen. Religionspädagogische Anmerkungen zum Projekt des Digitalen Humanismus
No full textBucher G. Dem Ruf der Sirenen widerstehen lernen. Religionspädagogische Anmerkungen zum Projekt des Digitalen Humanismus. In: Plaul C, Constanza C, eds. Humanität und digitale Ethik. Tübingen: Mohr Siebeck; Accepted
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