Abstract: A method for obtaining a model of a surface including the steps of obtaining measurements of geometrical data concerning specific points on the surface, making a grid of the surface, with the grid passing through said points, memorizing, at an address which is specific to each node of the grid, the coordinates of the node, the number of satellites of the node, information for access to the addresses of said satellites and thereafter to information which relates to them, and geometrical data which may be associated with said node; for each node, defining a local roughness index obtained from a weighted sum of the current coordinates of the node and its satellites, defining the sum of an overall roughness index representing the sum of all the local roughness indices, and of an overall index of the infringement of said geometrical data, iteratively adjusting the coordinates of indefinite nodes, by using at each adjustment the sum of a weighted combination of current node neighbor coordinates and of a combination

Abstract: The invention relates to recovery of an aprotic polar solvent from a saline aqueous solution of this solvent, by a process which consists in desalting the said solution by electrodialysis then in distilling the desalted solution.To avoid precipitation of metal hydroxides during the electrodialysis, the brine is kept at an acidic pH.

Abstract: A process is provided for improving the sulphur yield of a sulphur production unit using an acid gas containing H.sub.2 S and wherein said unit is comprised of a sulphur plant with a downstream purification unit. The H.sub.2 S resulting from hydrolysis of COS and CS.sub.2 is almost entirely recovered in the form of sulphur in the purification unit resulting in an improved sulphur output of the overall installation.

Abstract: An aluminosilicate gel containing an ST structuring agent whose composition is suitable for crystallization into a zeolite of the faujasite structural family is prepared. The gel then undergoes crystallization in order to form a zeolite precursor which consists of the zeolite containing the ST structuring agent in its cavities and channels, the zeolite being produced through the calcination of the precursor. The ST structuring agent consists of at least one compound from the alkylene polyoxides of formula (1) ##STR1## in which R and R', identical or different, each represents H or an alkyl radical in C.sub.1 to C.sub.4, X designates H or OH, m is equal to 2 or 3 and can differ from one pattern to another, and n is a number from 1 to 12. The zeolites thus obtained have a Si:Al ratio which is greater than 1 and which can go beyond 3, and show a cubic symmetry. The zeolites can be used, directly or after cation exchange, as adsorbants or as catalyst constituents.

Abstract: The disclosed method for the selective removal of H.sub.2 S from a H.sub.2 S-containing gas comprises contacting the gas in an absorption area (1) with a selective regeneratable absorbing liquid which absorbs the H.sub.2 S and regenerating by heating the absorbing liquid laden with H.sub.2 S in a regeneration area (3). The absorbing liquid coming out of the area (1) is sent to an enrichment area (2) through a conduit (25), a portion of the gases at the head of the area (3) is tapped through a valve (27) to form an acid gas flow enriched with H.sub.2 S and the remainder is introduced in the area (2) through a conduit (29), the absorbing liquid is tapped at the bottom of the area (2) and introduced through a conduit (25) in the area (3) and a gas stream is collected at the head of the area (2) and is injected through a conduit (22) in the area (1). Application to the simultaneous production of a gas flow highly enriched with H.sub.2 S and a gas having a fixed minimum content of H.sub.2 S.

Abstract: An enclosure 1 has a measurably variable volume chamber 2, a control for controlling the temperature of the fluid contained therein and apparatus for measuring the pressure of the fluid. The chamber is selectively connectable, on the one hand, to a filling device 6, for introducing the sample, and on the other hand to a fluid extraction apparatus 7, 8. The enclosure 1 is selectively connectable to a tubular loop 9 having a circulation pump 10 and apparatus 11 for measuring the density of the sample of circulating fluid. By varying the volume of chamber 2, the thermodynamic characteristics of monophase and diphase fluids can be accurately determined. The apparatus is especially useful for the study of fluid of hydrocarbon deposits.

Abstract: New application of microemulsions as buffers between the slurry and the cement in the cementation of oil wells. The microemulsions contain an amphoteric surfactant selected from the group of alkyl dimethyl betaines.

Abstract: A method of making homogeneous particulate compositions for use as heat-fusible adhesives which include a thermoplastic polymer and a gluing agent. The method includes the steps of preparing a mixture of water, the gluing agent, and a suspension agent, heating the mixture to the fusing temperature of the polymer, stirring in such a way that the molten mass is broken up into particles of about 0.005 to about 5 mm, cooling while stirring, and separating the particles from the aqueous phase.