Abstract: Titanium dioxide pigment of improved durability in paints comprises a particulate core of rutile titanium dioxide having an inner coating on the core of an oxide or hydrous oxide of zirconium, and a coating of dense amorphous silica on the inner coating. The pigment optionally has an outer coating of a hydrous oxide of aluminium.The pigments contain the oxide of hydrous oxide of zirconium in an amount of up to 5% expressed as ZrO.sub.2 and an amount of dense amorphous silica of up to 12% by weight expressed as SiO.sub.2 on the weight of TiO.sub.2.The pigments when incorporated in paints have extremely high durability.

Abstract: Titanium dioxide pigment having a high durability when used in paints comprises a particulate core of rutile titanium dioxide having an inner coating of dense amorphous silica on which is carried an outer coating of a hydrous oxide of zirconium. Optionally the pigment has an outer coating of a hydrous oxide of aluminum.The amount of dense amorphous silica is up to 12% by weight expressed as SiO.sub.2 and the amount of hydrous oxide of zirconium is up to 5% expressed as ZrO.sub.2 on the weight of TiO.sub.2. The outer coating of hydrous oxide of aluminium can be present in an amount of up to 6% by weight expressed as Al.sub.2 O.sub.3 on the weight of TiO.sub.2.A combination of these coatings has been found to be extremely advantageous in producing a paint containing the pigment having a very good durability and resistance to weathering.

Abstract: A method for steering solid propellant ballistic vehicles during powered flight which eliminates the requirement for cutoff control by allowing simultaneous fuel depletion and velocity-to-be-gained, V.sub.G, nulling. The vehicle booster is steered along a velocity trajectory of length equal to the remaining velocity capability, V.sub.CAP, which results in a fuel-inefficient trajectory. The trajectory is divided basically into three phases--an exit phase, a fuel-depletion guidance (FDG) phase and a short phase of constant attitude thrusting just prior to final stage burnout. For the exit phase the launch azimuth and the pitch-over magnitude can be varied from their usual fuel-efficient values. During fuel-depletion guidance the additional degree of freedom is the angle, .theta., between V.sub.G and the desired thrust direction, U.sub.S, where: ##EQU1## a.sub.T being the sensed acceleration vector.

Abstract: Aqueous pastes have been prepared by dispersing dried particulate material in water in the presence of a dispersing agent.A new process for the manufacture of aqueous pastes involves two-stage filtration in which a first stage filter cake is mixed with a dispersing agent in an amount sufficient to render the cake free-flowing which is then subjected to a second stage pressure filtration and the cake is then homogenized.Preferably the cake is of titanium dioxide and the cake from the first filtration is mixed with the dispersing agent in a sand mill. A membrane pressure filter is preferably used in the first and second filtration stages. During homogenization preferably a further amount of the dispersing agent is mixed with the filter cake. Aqueous paste prepared by this new process can have solids contents in excess of 70% by weight.