Pb2+ Selectivity of Two New Mono Pyrene Acetamide Calix[4]arenes

The synthesis of a new mono tert-butyl ester mono pyrene acetamide calix[4]arene 2 and 5,11,17,23-tetra(tert-butyl)-25-pyrene acetamide-27-acid calix[4]arene 3, that both present pyrene fluorescent functionalities is reported. The binding properties towards a variety of transition and non-transition metal cations have been determined along with a fluorescence study. Particular selectivity to lead cations was observe

Caractérisation et modélisation des mécanismes tribologiques aux interfaces outils-pièces-copeaux en usinage à sec de l'acier C45

Dans ce travail de thèse, une amélioration aussi bien à l échelle globale qu à l échelle locale a été apportée sur la compréhension des mécanismes tribologiques aux interfaces outil-pièce-copeau durant l usinage à sec de l acier C45 avec des outils en carbure de tungstène revêtus en TIN. Dans une première partie expérimentale, des essais de frottement ont permis d étudier la sensibilité des paramètres de frottement sur le comportement tribologique aux interfaces pion-pièce. Ainsi, l évolution du coefficient de frottement, du flux de chaleur et du coefficient de partage de chaleur aux interfaces outil-pièce-copeau ont été identifiés pour le couple de matériau frottant et frotté. Pour mieux comprendre ces phénomènes, une étude métallographique a été effectuée sur des échantillons. Elle a notamment permis l obtention des transformations métallurgiques au niveau de la surface superficielle de la pièce : des affinements des grains (déformation plastique) aux basses vitesses de frottement et des couches blanches (durcissement thermique) pour les grandes vitesses. Pour avoir plus de détails, un modèle numérique simulant l essai de frottement a été développé en se basant sur l approche Arbitraire Lagrangienne Eulérienne (A.L.E). Ce modèle nous a permis d avoir plus d informations sur les grandeurs locales de frottement (pression de contact, température de contact, vitesse locale de glissement, déformation plastique). Un modèle de frottement et un modèle de coefficient de partage de chaleur ont été identifiés à travers cette étude numérique. Dans la deuxième partie expérimentale, deux types d essais d usure ont été effectués dans des conditions similaires sur des pions et sur des plaquettes d outils de coupe de même nuance. Des analyses microscopiques et au MEB couplés à une analyse EDS ont été faites afin de mieux analyser les mécanismes tribologiques durant les essais d usure. Des similitudes de faciès d usure ont été observées à différentes échelles d analyse, sur les pions ainsi que sur les plaquettes d outils de coupe. Ces similitudes ont permis d aboutir à une corrélation des phénomènes tribologiques observés sur les pions et ceux observés sur les plaquettes.In this work, improved both global and local levels has been made on understanding the tribological mechanisms at the chip-tool-workpiece interface in dry machining of a AISI 1045 steel with a TiN coated carbide tool. In the first part, several friction tests have been performed to study the sensitivity of friction parameters on the tribological behavior at pin-workpiece interface. Thus, evolutions of the apparent friction coefficient, of heat flux and of heat flux partition ratio have been identified. To better understand these phenomena, a metallographic study was performed on the samples of the workpiece.It has enabled the achievement of metallurgical transformations in terms of surface area of the room : the refinement of grains (plastic deformation) friction at low speeds and white layers (thermal curing)for high speeds. These results show that the initial state of the steel (ferritic-pearlitic microstructure) has been changed, In fact, two phenomena have been observed. The first phenomenon has been observed for low sliding velocities. In this range of the sliding velocities, the grains have been crushed because of the large plastic deformations. The second phenomenon has been observed by increasing the friction velocity. In fact, the white zones have been identified at the surface layer and which have presented a different structure compared to the initial state of the steel. A 3D A.L.E. numerical model, simulating the friction test, enables to extract local information from the contact area, especially the contact pressure, the contact temperature and the average local sliding velocity. An adhesive friction model and a heat partition coefficient model depending on average local sliding velocity have been identified. These friction models can be utilized in a FEM of the cutting process in order to improve the understanding of the material flow and temperature distribution around cutting tools. In the second part, pin wear in the friction tests and tool wear in machining tests have been performed. To compare the phenomena observed at the tool-chip interfaces during the wear tests in machining with the phenomena observed at the pin-workpiece during the wear tests of friction, similarities of faces have been observed at different scales of analysis on the pins and on the cutting tool inserts.LYON-Ecole Centrale (690812301) / SudocSudocFranceF

Research on Membranes and Their Associated Processes at the Université Paris-Est Créteil: Progress Report, Perspectives, and National and International Collaborations

Research on membranes and their associated processes was initiated in 1970 at the University of Paris XII/IUT de Créteil, which became in 2010 the University Paris-Est Créteil (UPEC). This research initially focused on the development and applications of pervaporation membranes, then concerned the metrology of ion-exchange membranes, then expanded to dialysis processes using these membranes, and recently opened to composite membranes and their applications in production or purification processes. Both experimental and fundamental aspects have been developed in parallel. This evolution has been reinforced by an opening to the French and European industries, and to the international scene, especially to the Krasnodar Membrane Institute (Kuban State University—Russia) and to the Department of Chemistry, (Qassim University—Saudi Arabia). Here, we first presented the history of this research activity, then developed the main research axes carried out at UPEC over the 2012–2022 period; then, we gave the main results obtained, and finally, showed the cross contribution of the developed collaborations. We avoided a chronological presentation of these activities and grouped them by theme: composite membranes and ion-exchange membranes. For composite membranes, we have detailed three applications: highly selective lithium-ion extraction, bleach production, and water and industrial effluent treatments. For ion-exchange membranes, we focused on their characterization methods, their use in Neutralization Dialysis for brackish water demineralization, and their fouling and antifouling processes. It appears that the research activities on membranes within UPEC are very dynamic and fruitful, and benefit from scientific exchanges with our Russian partners, which contributed to the development of strong membrane activity on water treatment within Qassim University. Finally, four main perspectives of this research activity were given: the design of autonomous and energy self-sufficient processes, refinement of characterization by Electrochemical Scanning Microscopy, functional membrane separators, and green membrane preparation and use

5,11,17,23-Tetra-tert-butyl-25-(2’-pyridylmethylamidocarbonylmethyl)-calix[4]arene

5,11,17,23-tetra-tert-butyl-25-(2’-pyridyl methyl amidocarbonylmethyl)-calix[4]arene (3) has been synthesized in the cône conformation through reaction of the corresponding mono-ester with 2-aminomethylpyridine (picolylamine) and characterised using 1H NMR and MALDI-TOF mass spectral data as well as elemental analyses

Paraffin oil thermal diffusivity determination using a photothermal deflection setup with a 2.3μm pump: a first step towards methane detection

International audienceThe photothermal deflection technique, also known as "mirage effect", is a nondestructive method of evaluating thermal properties of solid, liquid or gaseous species. This technique will be used to detect pollutant absorption. As the deflection is stronger in liquids than gases, we will first consider the deflection in paraffin oil. We consider a medium that is heated by a modulated laser diode beam, and we measure the deflection of the probe beam passing through the heated region as a function of the distance between the axes of the beams. After some theoretical considerations and numerical simulations, we present the application of this method to the experimental determination of the thermal diffusivity of a liquid sample in excellent agreement with previously known values