Abstract: A treatment for waste pickling solutions containing iron and method of ferric oxide formation, consisting of spent acid with iron content, the addition therein of sodium hydroxide to adjust the pH value, the execution of a chemical reaction in another tank into which sodium hydroxide and air are added while the admixture is exposed to an ultraviolet beam circuit in a photo-oxidation process, and finally magnetic culling to separate ferric oxide in the solution.

Abstract: A warning apparatus to signal that a coverlet is out of position, includes a belt, a buckle mounted on one end of the belt, a rim on the buckle, a catch mounted on the other end of the belt, and a photoelectric circuit of a first photo sensitive element provided on the buckle and a second photo sensitive element provided on the belt. The first and second photo sensitive elements are separated a predetermined distance and connected in parallel to the photoelectric circuit means, and a buzzer is connected to the photoelectric circuit means.

Abstract: A clamping apparatus for hammering a hardened nail comprises a nail clamping device adapted to clamp a hardened nail, a ring sleeve receiving the clamping device at it's inner surface and an elongated handle connected at the outer surface of the ring sleeve. The clamping device is a truncated cone made of an elastic material and having an axial through center hole and a longitudinal through groove from the axial hole radially outwards to an outer surface of the cone. The ring sleeve has a tappered inner surface to taperingly engage with the truncated cone. The handle has predetermined length and two ends for connecting different sizes of ring sleeves.