Phase relationships in the system Li2O, B2O3‐B2O3 were studied by the quenching method using twenty compositions. The crystalline phases encountered were (a) Li2O, B2O3, which melts congruently at 849°± 2°C., (b) Li2O.‐2B2O3, which melts congruently at 917°± 2°C., (c) a new compound, 2Li2O‐5B2O3, which melts incongruently at 856°± 2°C. and dissociates below 696°± 4°C., (d) Li2O.3B2O3, which melts incongruently at 834°± 4°C. and dissociates below 595°± 20°C., and (e) probably Li2O.4B2O3, which melts incongruently at 635°± 10°C. Reactions were sluggish at temperatures near 600°C., resulting in metastable relations. Hence phase equilibrium data relating to the lower stability limit of Li2O.3B2O3 and to the upper stability limit of Li2O.4B2O3 are considered to be tentative. Properties of the glasses and crystalline phases were studied. The refractive index of the glasses increased with the addition of Li2O up to 22%, but further additions up to 40% had no substantial effect. Glasses containing less than 30% Li2O were water soluble. Limited data on the density and thermal expansion of the glasses are presented. Li2OB2O3 was euhedral, lath‐shaped, length‐fast, biaxial negative (2V = 27°), with nα= 1.540, nβ= 1.612, nγ= 1.616. Li2O.2B2O3 was uniaxial negative, with ne= 1.560, nw= 1.605. Li2O.3B2O3 was biaxial negative (2V = 75° to 80°), with nα= 1.576, nβ= 1.602, nγ= 1.605. X‐ray powder diffraction data for the five crystalline compounds are presented. Thermal expansion data for Li2O‐B2O3 and Li2O.2B2O3 and limited data on the fluorescent properties of the compounds are given. X‐ray diffraction data are also presented for Li2O.B2O3.4H2O and Li2O.‐5B2O3. 10H2O. Li2O B2O3 was obtained by heating the first hydrate at 450° to 680° C. X‐ray diffraction showed Li2O.4B2O3 and Li2O‐3B2O3 to be the crystalline products obtained during heating the decahydrate at 500°C. and 600°C., respectively.

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Nine compositions containing 40 to 68% B2O3 were used to study the high‐lithia portion of the system Li2O‐B2O3 by quenching and differential thermal analysis methods. The compounds 3Li2O 2B2O3 and 3Li2O B2O3 melted incongruently at 700°± 6°C, and 715°± 15°C., respectively. The compound 2Li2O B2O3 is assumed to dissociate slightly below 650°± 15° C., although the data could also be interpreted as in‐congruent melting. Below 600°± 6°C. it does dissociate to the 3:2 and 3:1 compounds. In this narrow temperature interval the 2:1 compound had an inversion at 618°± 6°C. Both forms of the 2:1 compound could be quenched to room temperature. X‐ray diffraction data for the compounds are tabulated, and the complete phase diagram for the system Li2O‐B2O3 is presented.

ABSTRACT:The article deals with the synthesis of two polysaccharide-based graft copolymers of acrylamide, namely, starch-g-polyacrylamide (St-g-PAM) and amylopecting-polyacrylamide (Ap-g-PAM). Intrinsic viscosity of the graft copolymers was determined. A flocculation jar test was carried out with Ϫ200# ASTM particles for two coking and two noncoking coal samples from Indian coalfields. It is observed that both the grafted products are very effective flocculants in bringing down the turbidity of supernatant liquid of coking coal fines suspension. Though they are effective flocculants in the case of noncoking coal suspension as well, the supernatant turbidity remains somewhat high. Ap-g-PAM performed better than St-g-PAM, which is distinctly apparent in the case of noncoking coal suspension. This may be ascribed to the presence of longer grafted polyacrylamide chains in case of Ap-g-PAM.

The linear thermal expansion coefficient of tetrahedrally coordinated AIIBVIand AIIIBVsemiconductors has been calculated using plasmon energy data. A simple relation between the bond length and plasm on energy has been derived. The calculated values of thermal expansion coefficient and bond length have been compared with the experimental values and the values reported by differentworkers. An excellent experiment has been obtained between them.