derniers depôts

Ajouté le 24/03/2019

This dissertation focuses on cyclization reactions of 1,6-enynes involving ruthenium catalysts. Three different types of cyclization were developed from readily available precursors, such as 1,6-enynes and alkynes. In one application, a novel ruthenium-catalyzed hydroalkynylative cyclization of 1,6-enynes using terminal alkynes as co-reactants was explored. This reaction provides and entry to five-membered rings featuring an exocyclic 1,5-enyne motif.

Ajouté le 23/03/2019

We propose an approach based on geometric phase for performing several types of shearing interfer-ometry through a robust, compact, common-path setup. The key elements are two identical parallel plates with spatially-varying birefringence distributions , which perform the shearing by writing opposite geometric phases on the two circular polarization components of the linearly polarized incident wavefront.

Ajouté le 23/03/2019

A recent strand of papers use sharp regression discontinuity designs (RDD) based on age discontinuity to study the impacts of minimum income and unemployment insurance benefit extension policies. This design challenges job search theory, which predicts that such RDD estimates are biased. Owing to market frictions, people below the age threshold account for future eligibility to the policy. This progressively affects their search outcomes as they get closer to entitlement.

Ajouté le 23/03/2019

The asymptotic behavior of the solutions of the second order linearized Vlasov-Poisson system around homogeneous equilibria is derived. It provides a fine description of some nonlinear and multidimensional phenomena such as the existence of Best frequencies. Numerical results for the 1D×1D and 2D×2D Vlasov-Poisson system illustrate the effectiveness of this approach.

Ajouté le 21/03/2019

In this paper, the multimodal nonlinear elastic behavior of concrete, which is representative of a consolidated granular material, is modeled numerically. Starting from a local three-dimensional softening law, the initial stiffness properties are re-estimated according to the local strain field. The experiments deal with samples of thermally damaged concrete blocks successively excited around their first three modes of vibration.

Ajouté le 20/03/2019

Depending of the geometry of the domain, one can define –at least– three different Stokes operators with Dirichlet boundary conditions. We describe how the resolvents of these Stokes operators converge with respect to a converging sequence of domains.

Ajouté le 20/03/2019

We introduce and study a complexity function on words c x (n), called cyclic complexity, which counts the number of conjugacy classes of factors of length n of an infinite word x. We extend the well-known Morse–Hedlund theorem to the setting of cyclic complexity by showing that a word is ultimately periodic if and only if it has bounded cyclic complexity. Unlike most complexity functions, cyclic complexity distinguishes between Sturmian words of different slopes.

Ajouté le 19/03/2019

This study presents the preparation and the evaluation of performance of a new monolithic catalyst in microreactor. The transfer hydrogenation of p-nitrophenol by formic acid is chosen as the model reaction for the comparison of the monolith with a traditional packed-bed microreactor containing commercial catalyst.This thesis includes an important experimental part.

Ajouté le 22/03/2019

Storage conditions of the spawn of edible fungi are of major importance to facilitate the production of mushrooms. Here, standard storage conditions at 10 °C or 15 °C were used and the potential of colonization of standard European compost by the tropical species Agaricus subrufescens was assessed during the spawn running phase.

Ajouté le 26/03/2019

The system laccase/mediator/dioxygen is able to trigger radical reactions with radical precursors which are not natural substrates of this enzyme. The radical generation has been accomplished by single electron transfer oxidation of a 1,3-dicarbonyl precursor. The process is exemplified with a radical cascade.