Reference

Tensimetric study of ammonium paramolybdate and paratungstate

Tensimetric study of ammonium paramolybdate and paratungstate. Volkov, A. I.; Komshilova, O. N.; Gaidym, I. L.; Novikov, G. I. (BTI, USSR). Khim.There are some reagents with their cas registry numbers 12054-85-2 and 11120-25-5 are used in this study. Khim. Tekhnol. (Minsk), 17, 124-5 (Russian) 1982. CODEN: KKTEDK. DOCUMENT TYPE: Journal CA Section: 54 (Extractive Metallurgy) Section cross-reference(s): 69 The thermal decompn. of (NH4)6Mo7O24.4H2O and (NH4)5HW6O21.4H2O was studied.. Vapor pressure measurements showed the paramolybdate decompn. stages of: (a) loss of hydrate water, and (b) dissocn. into MoO3, NH3, and H2O. Free energy change in the dehydration was 13.1 ± 1.6 kcal/mol for paramolybdate, and 12.7 ± 1.8 for paratungstate. .

Combination of nonsupervised and supervised pattern recognition methods for classification of tungsten materials

Combination of nonsupervised and supervised pattern recognition methods for classification of tungsten materials. Henrion, Guenter; Henrion, Rene; Lunk, Hans Joachim; Riedel, Volkhardt (Sekt. Chem., Humboldt-Univ., Berlin DDR-1040, Ger. Dem. Rep.). Chem. Tech. (Leipzig), 38(12), 525-8 (German) 1986. CODEN: CHTEAA. ISSN: 0045-6519. 11120-25-5 which is the cas registry number is also used here. DOCUMENT TYPE: Journal CA Section: 49 (Industrial Inorganic Chemicals) Multivariate classification of 67 barrels with ammonium paratungstate according to different group qualities represented by 11 trace element concens. is described. Using BASIC programs for microcomputers (nonlinear mapping, principal components plot, nonhierarchical clustering, variance, and discriminant anal.) the combination of clustering and discriminant anal. proved to be best, i.e., a combination of nonsupervised and supervised pattern recognition. After redn. of the 11 parameters to 5 or 4 (Mo, K, Na, Fe, Ca) 3 main groups of qualities were found. The described method is recommended for similar problems of pattern recognition and classification. .