Abstract: A refractive index detector is described comprising a waveguide, means for contacting said waveguide with a fluid, a light source and means to transmit light into said waveguide, means for detecting light exiting from said waveguide as an indication of the refractive index of said fluid and means to automatically change the angle of incidence of the light entering said waveguide in response to changes of refractive index of said fluid. A preferred embodiment of the detector for use as a detector for gradient elution chromatography has means to indicate the rate of change of refractive index. A preferred means to automatically change the angle of incidence of the light entering the waveguide is a movable prism. It is preferred to use a monochromatic light source in the detector. It is preferred to provide reference means for the detector to compensate for changes in intensity of the light output from said light source.

Abstract: A device useful as a detector for fluid (liquid or gas) chromatograph effluent comprising a light source, a cell divided into sample and reference fluid compartments separated by an opaque diaphragm sufficiently thin to form a Fraunhofer diffraction pattern, means to introduce and remove sample and reference fluids to and from said compartments, means to collimate light from said light source at said diaphragm and through the compartments of said cell, photodetector means capable of sensing phase shift of said diffraction pattern, and means to focus light exiting said compartments on said photodetector. When used as a detector for chromatograph effluent the sample compartment should have a volume less than the smallest volume of eluted fractions from the chromatograph with which the device is used. An especially significant and novel feature of the device is the cell used in the refractometer.

Abstract: Mixtures comprising compounds of the formula ##EQU1## wherein A is either NH.sub.2 or N=P(NH.sub.2).sub.3, provided at least one A is N=P(NH.sub.2).sub.3, have been found to be good flame-retardants for material made from cotton or polyester-cotton having about 30 to 70% by weight cotton. Conveniently the material can be treated with an aqueous solution containing a sufficient amount of said mixtures and the material dried to make the material self extinguishing. Then the treated and dried material is cured at a sufficient temperature to bond said compounds to the material. Alternatively and usually preferably the drying and curing can be accomplished as a single operation.

Abstract: Large void-free castings of polyethylene can be made by blending high density polyethylene pellets with low density polyethylene powder, followed by heating to above the melting point of the low density polyethylene and below, or only slightly above, the melting point of the high density polyethylene. Flame proofing additives, crosslinking agents and other materials can be readily incorporated into the blend before fusing. The mixture of high density and low density polyethylene significantly reduces the amount of shrinkage which takes place during the cooling from the melting temperature to ambient temperature. The low density polyethylene should have a sufficiently low melt viscosity so that it will flow under small pressures above the melting temperature.

Abstract: A process for rapidly producing a substantially uniform, solid, cellular thermoplastic article comprising the steps of: (a) charging a vessel with (1) a solid thermoplastic polymer, (2) a solvent mixture the amount of which in the range of from about 25-50% by weight of said polymer boils at or below 0.degree.C. and to prevent shrinkage the minor amount of which in the range of from about 3-30% by weight of said polymer boils at or near 20.degree.C.

Abstract: Intumescent compositions are described which when deposited on a substrate protect the substrate against heat and fire damage for an appreciable time, and these compositions are readily removed from the substrate by water washing or water scrubbing both before and after intumescing. Another advantage of these compositions is that they give off very little smoke when exposed to heat and fire. The most effective of these compositions comprise monoammonium phosphate and/or diammonium phosphate as a heat- and fireproofing agent, urea and/or cyanoguanidine (dicyandiamide) as a gas forming or gas generating agent to promote the intumescence, sucrose (sugar) together with the phosphate to promote initial intumescence at low temperature and titanium dioxide as a heat-reflecting agent. Certain possible alternatives to the compounds named above are also named.

Abstract: The new product, a Cl.sub.3 P=N--N=PCl.sub.3 + NH.sub.3 reaction product, has been found to be an excellent flameretardant for material made from cellulose such as cotton, paper and sponge; polyester, wool and blends thereof. Conveniently the material can be treated with an aqueous solution containing a sufficient amount of the product and the material dried to make the material self-extinguishing. Then the treated and dried material is cured at a sufficient temperature to bond the product to the material. Alternatively, and usually preferably, the drying and curing can be accomplished as a single operation.

Abstract: Aqueous foamable compositions can be used to suppress coal dust, especially respirable coal dust, i.e., coal dust having particle size less than about 10 microns. These compositions are composed principally of water with a minor amount of an interpolymer of:A. a polymerizable vinyl ester andB. a partial ester compound interpolymerizable therewith selected from the group consisting of partial esters of ethylenically unsaturated aliphatic dicarboxylic acids and anhydrides containing from 4-8 carbon atoms and mixtures thereof; said dicarboxylic acid or anhydride having up to half of its acidic hydrogen atoms replaced by lower alkyl groups of 1-8 carbon atoms and mixtures thereof to bind the coal dust and give body to the foam, and a minor amount of a detergent wetting agent to promote foaming and the wetting of the coal by water.These interpolymers bind the coal dust and reduce or prevent reacrosolation after the foam has collapsed. These interpolymers also serve to give body to the foam, i.e.