Abstract: The invention relates to an improved process for providing purified styrenic monomers, such as styrene, from styrene-containing polymer waste. Styrene-containing waste is depolymerized in a suitable reactor, and the depolymerization products are condensed and separated in a three-step distillation process.

Abstract: Method and apparatus for handling a supported tubular string with a string elevator and a spider on a rig to prevent damaging contact between the string elevator and spider while facilitating further connections of add-on tubular segments. The string elevator and supported tubular string descend toward the spider until reaching a predetermined position. The process of setting the spider into engagement of the tubular string is automatically initiated in response to detecting the predetermined position of the string elevator. With the spider set, the string elevator can be unloaded. Optionally, the method may also automatically terminate the string elevator descent in response to detecting that the spider has been set. A preferred apparatus for detecting the position of the elevator includes a tilt switch secured to a fixed position along the length of the Kelly hose.

Abstract: Method and apparatus for handling a supported tubular string with a string elevator and a spider on a rig to prevent damaging contact between the string elevator and spider while facilitating further connections of add-on tubular segments. The string elevator and supported tubular string descend toward the spider until reaching a predetermined position. The process of setting the spider into engagement of the tubular string is automatically initiated in response to detecting the predetermined position of the string elevator. With the spider set, the string elevator can be unloaded. Optionally, the method may also automatically terminate the string elevator descent in response to detecting that the spider has been set. A preferred apparatus for detecting the position of the elevator includes a tilt switch secured to a fixed position along the length of the Kelly hose.

Abstract: The polymer chain comprises(a) one or more monomers possessing a nematogenic, chiral or smectogenic group, or a mixture of monomers possessing a nematogenic group with those possessing a chiral group, and(b) one or more monomers possessing a radical of a pleochroic dye, and the nematogenic, the chiral and the smectogenic groups are bonded to the polymerizable group either directly or, like the dye radicals, via a spacer.The polymers can be used, together with low molecular weight liquid crystals or liquid crystal mixtures, in electrooptical displays.

Abstract: Finely divided, pulverulent carotinoid or retinoid compositions, in which the carotinoid or retinoid essentially has a particle size of less than 0.5 micron, are prepared by a process wherein a carotinoid or retinoid is dissolved in a volatile, water-miscible, organic solvent at from 50.degree. C. to 200.degree. C., if necessary under superatmospheric pressure, within the space of less than 10 seconds. The carotinoid is immediately precipitated, in a colloidally disperse form, from the molecularly disperse solution by rapidly mixing the latter with an aqueous solution of a swellable colloid at from 0.degree. C. to 50.degree. C., and the resulting dispersion is freed from the solvent and the dispersing medium in a conventional manner.

Abstract: A method of recovering fluorine, e.g. as hydrogen fluoride, from wastes of aluminum electrolysis furnaces, chemisorbents, adsorbents or absorbents, etc. in which the fluorine-containing material is subjected to pyrohydrolysis in an expanded fluid bed and the HF-containing gas is subjected to condensation or scrubbing for the removal of the HF therefrom. According to the invention, the exhaust gases from the fluidized bed are cooled by direct contact with solids which can be circulated in a separate cycle and are themselves cooled in a cooler, e.g. by contact with gas which is to be fed to the expanded fluidized bed. The circulated solids thus allow recovery of the sensible heat of the gas without diluting it.