Abstract: Disclosed is a sealing composition for soil barriers. The composition is formed of 50 to 95% of a solids mixture of clay minerals and fillers, the clay mineral being 5 to 90% of the solids mixture; a binding agent which is a mixture of an aqueous solution of alkali water glass with a silane of the formula R--Si(OR'.sub.3) in which R is an aliphatic moiety of 1 to 6 carbon atoms, which may be substituted with reactive groups, and R' represents identical or different alkyl moieties of 1 to 4 carbon atoms; and water.

Abstract: A soil injection agent on an alkali metal silicate basis, containing as gelling agent trialkoxysilanes of the formula R-Si(OR').sub.3, in which R is an aliphatic moiety of 1 to 6 carbon atoms and R' represents equal or different alkyl moieties of 1 to 4 carbon atoms, is adjusted for properties by the addition of acid alkali metal phosphates or ammonium phosphates and/or phosphoric acid. The addition improves the sealing and strengthening action of the gels and permits a reduction of the silane content, without impairing the resistance of the gels to pollutants.

Abstract: Liquid or water-soluble pollutants which have entered into permeable soil strata are prevented from spreading and contaminating ground water by surrounding the contaminated zone on all sides with vertical barriers and closed off at the bottom by a horizontal injected floor which seals not only against water but also against the pollutants. The pollutant resistance of the floor is achieved by the use of injection materials on a silicate basis containing trialkoxysilanes of the general formula R-Si(OR').sub.3.

Abstract: The present invention relates to liquid mixtures of alkali metal silicates, water, and trialkoxysilanes of the general formula R--Si(OR').sub.3, which harden to form silica-containing gels within a predetermined length of time. The mixtures can contain additional means for influencing the gelling and the gel strength. The most important field of application of the gels in accordance with the invention is the stabilization of soils in architecture and civil engineering.

Abstract: The present invention relates to compositions for making sealing walls, dump linings and the like, especially barriers placed in the ground. The compositions contain expandable clay minerals, cement and fillers in aqueous suspension, as well as additives of alkali metal aluminates and alkoxy alkylsilanes. On the basis of these additives, the sealing action against water and pollutants is substantially improved, so that sealing walls prepared therefrom, especially in combination with an also pollutant-resistant sealing floor, can be used for the encapsulation of pollutants in permeable soils.

Abstract: A position display instrument for light spot display on a map of the position of vehicles, in particular aircraft or helicopters. The instrument comprises a flat map holder for accommodating and holding map sheets in an exact position, a light transmitter located below the map holder for producing a light spot on the map sheet and movable in two coordinates by positioning means, a microcomputer to which the grid coordinates of the vehicle position are applied from a navigational computer and by which the positioning means are controlled, a memory for storing map data, said memory cooperating with the microcomputer, and display means which is connected to the microcomputer and by which the map sheet or map field required for the respective grid coordinates is displayed.

Abstract: Oligomeric alkylene terephthalates having an average degree of condensation of 4 to 7 are produced by passing dimethylterephthalate and diol having at least 3 carbon atoms downwardly through a series of reaction chambers, each outfitted with stirring and heating means employed so that the temperature increases from stage to stage. Thereby transeterification is effected. The chambers are interconnected so that the methanol evolved in each chamber is vented without being admixed with the material undergoing transesterification in any of the other chambers. The transesterification product is then condensed at elevated temperature and under vacuum to produce the oligomer. The oligomers are high reactivity so that the further condensation thereof to polyesters is simplified.