Practical asymmetric access to carboxy-differentiated aspartate derivatives via 1,3-dipolar cycloaddition of a nitrone with (R)-4-ethyl-N-vinyloxazolidin-2-one

A new practical approach to enantioenriched carboxy-differentiated aspartate derivatives was achieved in three steps via the 1,3-dipolar cycloaddition of N-benzyl-α-carbonyloxyethylnitrone with (R)-4-ethyl-N-vinyloxazolidin-2-one and chemoselective nucleophilic displacement of aspartimide under appropriate conditions (racemization less than 3%).     

Pareto memetic algorithm for multiple objective optimization with an industrial application

Multiple objective combinatorial optimization problems are difficult to solve and often, exact algorithms are unable to produce optimal solutions. The development of multiple objective heuristics was inspired by the need to quickly produce acceptable solutions. In this paper, we present a new multiple objective Pareto memetic algorithm called PMS^MO. The PMS^MO algorithm incorporates an enhanced fine-grained fitness assignment, a double level archiving process and a local search procedure to improve performance. The performance of PMS^MO is benchmarked against state-of-the-art algorithms using 0–1 multi-dimensional multiple objective knapsack problem from the literature and an industrial scheduling problem from the aluminum industry.     

Ram extrusion force for a frictional plastic material: model prediction and application to cement paste

We developed a model to predict the ram extrusion force of frictional plastic materials such as cement-based pastes. The extrusion of cement-based materials has already been studied, but the interaction between shaping force and paste behaviour still have to be understood. Our model is based on the plastic frictional behaviour of cement-based materials and integrates the physical mechanisms that govern material extrusion flow and extrusion force increase. When the process starts, a pressure gradient is created in the extruder due to wall friction of the paste that is submitted to plug flow. It induces a consolidation of the material. As a result, a large increase of extrusion force appears. A Coulomb law is used to model cement-based materials, which is considered as consolidating granular media. Such modelling is compared with experimental results. Tests were carried out on extrudible cement pastes. Modelling and experimental results are in good agreement.Paper presented at the Annual European Rheology Conference, Grenoble, April 2005     

Optimal Internal Stabilization of the Linear System of Elasticity

We address the non-linear optimal design problem which consists in finding the best position and shape of a feedback damping mechanism for the stabilization of the linear system of elasticity. Non-existence of classical designs are related to the over-damping phenomenon. Therefore, by means of Young measures, a relaxation of the original problem is proposed. Due to the vector character of the elasticity system, the relaxation is carried out through div-curl Young measures which let the analysis be direct and the dimension independent. Finally, the relaxed problem is solved numerically, and a penalization technique to recover quasi-optimal classical designs from the relaxed ones is implemented in several numerical experiments. A. Münch was partially supported by grants ANR-05-JC-0182-01 and ANR-07- JC-183284. P. Pedregal was supported by project MTM2004-07114 from Ministerio de Educación y Ciencia (Spain), and PAI05-029 from JCCM (Castilla-La Mancha). F. Periago was supported by projects MTM2004-07114 from Ministerio de Educación y Ciencia (Spain) and 00675/PI/04 from Fundación Séneca (Gobierno Regional de Murcia, Spain).     

Intramolecular H-Bond Dynamics of Catechol Investigated by THz High-Resolution Spectroscopy of Its Low-Frequency Modes

Catechol is an oxygenated aromatic volatile organic compound and a biogenic precursor of secondary organic aerosols. Monitoring this compound in the gas phase is desirable due to its appreciable reactivity with tropospheric ozone. From a molecular point of view, this molecule is attractive since the two adjacent hydroxy groups can interchangeably act as donor and acceptor in an intramolecular hydrogen bonding due to the tunnelling between two symmetrically equivalent structures. Using synchrotron radiation, we recorded a rotationally-resolved Fourier Transform far-infrared (IR) spectrum of the torsional modes of the free and bonded -OH groups forming the intramolecular hydrogen bond. Additionally, the room temperature, pure rotational spectrum was measured in the 70–220 GHz frequency range using a millimeter-wave spectrometer. The assignment of these molecular transitions was assisted by anharmonic high-level quantum-chemical calculations. In particular, pure rotational lines belonging to the ground and the four lowest energy, vibrationally excited states were assigned. Splitting due to the tunnelling was resolved for the free -OH torsional state. A global fit combining the far-IR and millimeter-wave data provided the spectroscopic parameters of the low-energy far-IR modes, in particular those characterizing the intramolecular hydrogen bond dynamics.     

R-trees and laminations for free groups I: algebraic laminations

This paper is the first of a sequence of three papers, wherethe concept of a real tree dual to a measured geodesic laminationin a hyperbolic surface is generalized to arbitrary real treesprovided with a (very small) action of a free group by isometries.Laminations for free groups are defined with care in three differentapproaches: algebraic laminations, symbolic laminations, andlaminary languages. The topology on the space of laminationsand the action of the outer automorphisms group are detailed.     

Ueber die Alkaloide der Chinarinden

Ohne Zusammenfassung