ParisTech

About: ParisTech is a education organization based out in Paris, France. It is known for research contribution in the topics: Finite element method & Residual stress. The organization has 1888 authors who have published 1965 publications receiving 55532 citations. The organization is also known as: Paris Institute of Technology & ParisTech Développement.

Solubilities of ferrocene and acetylferrocene in supercritical carbon dioxide

Abstract: In this work, the solubilities of ferrocene and acetylferrocene in supercritical carbon dioxide (scCO2) were measured using an analytical method in a quasi-flow apparatus. High-performance liquid chromatography was applied through an online sampling procedure to determine the concentration of ferrocene and acetylferrocene in the scCO2 phase. The experiments were performed within a temperature range of 308–348 K and at pressures ranging from 7.7 to 24.4 MPa. Acetylferrocene is the product of the Friedel–Crafts acylation reaction of ferrocene and has many applications in the material and pharmaceutical industries. The molar solubilities at the applied conditions range from 8.9 to 31.2 × 10−4 for ferrocene and 2.5 to 79.2 × 10−4 for acetylferrocene. The existence of a cross-over area for acetylferrocene was detected at a pressure of around 15 MPa and for ferrocene at a pressure of around 10 MPa. The comparison between the experimental solubility data shows that ferrocene is more soluble in scCO2 at lower pressures, while at higher pressures acetylferrocene is more soluble in scCO2. The reason for this behavior is a trade-off between the lower polarity of ferrocene (more dominant at lower pressures) and the higher volatility of acetylferrocene (more dominant at higher pressures). Results obtained in this work show that the solubility of the reaction product acetylferrocene in scCO2 is sufficiently high to use scCO2 extraction at high pressures to separate it from its reactant ferrocene in Friedel–Crafts acylation processes.

Numerical analysis of unsteady cavitating flow in an axial inducer

Abstract: This article presents a numerical simulation of an unsteady cavitating flow. First, the analysis was carried out for a two-dimensional (2D) venturi-type geometry, and then for a 2D blade ca...

Positive definite Toeplitz completion in DOA estimation for partially-augmentable nonuniform linear antenna arrays

Abstract: Maximum-entropy positive-definite completion for partially-specified Toeplitz covariance matrices is developed for DOA estimation in partially-augmentable antenna arrays (those that have an incomplete set of covariance lags). Both the spatial covariance matrix estimation problem and the spatial spectrum estimation problem must be formulated as positive definite Toeplitz completion problems. The latter problem is investigated for two cases; firstly in the case where the available covariance lags ate supposed to be precisely known (deterministic completion). Secondly, we investigate the case where we assume we have sufficient statistics for the DOA estimates in the form of the direct data covariance matrix, obtained by sample averaging on a set of N independent vectors ("snapshots") originating from a complex Gaussian distribution.

Solution of Static Field Problems With Random Domains

Abstract: A method to solve stochastic partial differential equations on random domains consists in using a one-to-one random mapping function which transforms the random domain into a deterministic domain. With this method, the randomness is then borne by the constitutive relationship of the material. In this paper, this method is applied in electrokinetics in the case of scalar potential and vector potential formulations. An example is treated and the proposed method is compared to a nonintrusive method (NIM) based on the remeshing of the random domains.