José Sanchez

Gas diffusion and sorption properties of polysiloxane membranes prepared by PECVD

Abstract Thin a-SiO x C y H z film membranes were deposited from two different cyclic and linear organosilicon precursors in a low-frequency plasma polymerization process. The qualification of the films for effective gas permeation membranes was tested on the ester of cellulose substrates using N 2 , H 2 , CO 2 and CH 4 . The gas permeability and diffusion coefficients were determined by using the constant-volume pressure-increase method. The solubility coefficients ( S ) were obtained by using a gravimetric method with a quartz microbalance. Correlations between the composite plasma parameter ( V / FM ) ( V : input voltage, F : monomer flow rate and M : monomer molecular weight), which describes the energetic character of the plasma and the permeation performances of plasma polysiloxane membranes were established. Permeation measurements reveal that a wide range of gas transport properties can be obtained according to the applied plasma energy. The global mass transfer could be controlled by diffusion or sorption mechanism according to the relative influence of the different structural factors (chain packing density, chain flexibility and chemical composition) of plasma polysiloxane films directly related to deposition parameters.

Poly(ethylene oxide-co-epichlorohydrin) membranes for carbon dioxide separation

Abstract The gas permeability characteristics of poly(ethylene oxide- co -epichlorohydrin) films were determined by using the constant volume and pressure-increase method. Permeation measurements reveal that a wide range of gas transport properties can be obtained according to the ethylene oxide/epichlorhydrin ratio in the copolymer. The copolymers show very high permeability (up to 105 Barrer) and selectivity for carbon dioxide respect to nitrogen and methane (αCO 2 /N 2 : 63 and αCO 2 /CH 4 : 17). The global mass transfer and selectivity seem to be controlled mainly by the carbon dioxide sorption mechanism and are directly related with the ethylene oxide content in the copolymers.

Chapter 11 Current developments and future research in catalytic membrane reactors

Publisher Summary This chapter discusses the current developments and future research in catalytic membrane reactors. Catalytic membrane reactors have been fully demonstrated at the laboratory scale, the most important systems studied being dehydrogenation and oxidation reaction. Membrane reactors combine two different functions—that is, reaction and separation into a single operation. Solid oxide type membranes are the dense inorganic membranes that have been used in membrane reactor applications. These materials (solid oxide electrolytes) are also finding widespread application in the area of fuel cells and as electrochemical oxygen pumps and sensors. The applications of membrane reactors involve the equilibrium-limited dehydrogenation reactions and the efficient removal of hydrogen. To facilitate the transport across the membrane in laboratory studies, a sweep gas or a vacuum in the permeate side or a pressure gradient is applied across the membrane. The use of solid oxide membranes in partial oxidation reactions aims to avoid the complete oxidation of the desired partial oxidation products. When compared to similar efforts using microporous membranes, solid oxide membrane reactors are at a disadvantage (except for reactions that take place at high temperatures) because oxygen transport through the oxide lattice is generally low when compared with the permeability of porous materials.

Sorption and permeation characteristics of hybrid organosilicon thin films deposited by PECVD

Abstract Thin a-SiO x C y H z film membranes were deposited from hexamethyldisiloxane precursor on ester of cellulose porous substrates at low-frequency plasma conditions. The sorption properties of the films were measured for CH 4 , C 2 H 6 , C 3 H 8 , n -C 4 H 10 and i -C 4 H 10 by using a gravimetric method with a quartz microbalance. The gas permeability coefficients were determined by using the constant-volume pressure-increase method. Correlations were established between the physical parameters of the penetrants and the corresponding sorption, permeation and diffusion coefficients observed.

Robotic Manipulation and Sensing of Deformable Objects in Domestic and Industrial Applications: A Survey

We present a survey of recent work on robot manipulation and sensing of deformable objects, a field with relevant applications in diverse industries such as medicine (e.g. surgical assistance), food handling, manufacturing, and domestic chores (e.g. folding clothes). We classify the reviewed approaches into four categories based on the type of object they manipulate. Furthermore, within this object classification, we divide the approaches based on the particular task they perform on the deformable object. Finally, we conclude this survey with a discussion of the current state-of-the-art approaches and propose future directions within the proposed classification.