Abstract: Silica sols with a high content of microgel and particles with a specific surface area within the range 300 to 700 m.sup.2 /g, preferably 400 to 650 m.sup.2 /g. The sols can be prepared by acidification or a water glass solution and alkalization at a certain dry content, alternatively to a certain pH. The sols are particularly suitable for use as additives in papermaking in combination with cationic polymers and especially in combination with cationic acrylamide based polymers.

Abstract: The present invention relates to a sized paper containing a hydrophobic zeolite. Suitably, the sized paper is fine paper, kraft liner or paperboard. In paperboard intended for solid or liquid foodstuffs, tobacco or medicines, use is also made of the capacity of the zeolite to reduce, by adsorption, the problem of transfer from the package to its content of substances causing undesirable taste or hazardous substances. The present invention also relates to a method for production of the sized paper by forming and dewatering a suspension of lignocellulose-containing fibres, where the dewatering is carried out in the presence of a hydrophobic zeolite. Due to the inert nature of the zeolite, it can be used in papermaking within a very broad pH range. The present invention also relates to the use of a hydrophobic zeolite for the production of sized paper as well as use of the thus-sized paper in packaging material.

Abstract: A double isolated electrically shielded screen room in which all side, ceiling and floor panels thereof are provided with peripheral grooves. A tongue strip matingly engages the grooves in adjacent panels and clamping is completed with bolts. This construction minimizes the number of individual elements required for the screen room and facilitates assembly and disassembly. To reduce the possibility of the wood frame members being split, they may be partially cut through at the base of each groove. Alternatively, the frame members could be fully cut through, resulting in two individual pieces, permitting more freedom in putting the shielding on each panel.

Abstract: A double isolated electrically shielding screen room is characterized in that all of the side, ceiling and floor panels thereof are selectively provided with either male or female configured marginal edges defining tongues and grooves for interconnection of the panels without need for separate shielding strips. Overlapping shielding contacts between connected panels lie in parallel planes and are secured under compression in directions perpendicular to the contacts with great isolation efficiency by outwardly concealed clamping means applied from inside the room assembly, so that floor space around the room is economically conserved. The particular construction minimizes the number of individual elements required for the screen room and facilitates its assembly and disassembly.