The relative activities of the members of the principal radioactive families, with respect to the initial activities of chosen
parents were calculated for a wide range of time intervals. Tables and graphs that are useful for radiochemistry, source standardization
and chronology are presented.
Authors:V. I. Pet’kov, E. A. Asabina, A. V. Markin, N. N. Smirnova, and D. B. Kitaev
Summary The thermodynamic data for NZP compounds MZr2(PO4)3 (M=Na, K, Rb, Cs, Zr0.25) and Na5D(PO4)3 (D=Ti, Zr) are reported. The heat capacities of the phosphates were measured between T=7 and T=640 K. The standard enthalpies entropies, and Gibbs functions of formation at T=298.15 K were derived. The obtained thermodynamic characteristics of phosphates of the NZP type structure and literature data are summarized. Thermodynamic functions of reactions of solid-state synthesis were calculated and the usability of ceramic technology for obtaining NZP compounds was proved.
Phase diagrams for cuprates of alkaline earth and rare earth elements are presented, covering binary to quintenary oxides and including selected solid solution series with other elements. Elementary crystal chemical data are included for identification of the occurring phases. Chemical stability is discussed with respect to the high-temperature reactions with Lewis acids like CO2, protons, etc. Particularly the occurrence of oxide carbonates is consistently pointed out as one of the possible reasons for contradictory results in phase diagrams which comprise oxides with high basicity.
Thermally stable mesoporous aluminophosphates (AIPO) and silicoaluminophosphates (SAPO) were prepared at room temperature
in the presence of a cationic surfactant and an organic base. These materials possess high surface areas and regular mesopores
of approximately 35 Å diameter. By contrast to microporous crystalline aluminophosphate molecular sieves, mesoporous compounds
are amorphous and characterized by Al/P ratios greater than 1. These particularities are responsible for a strong Lewis acidity,
as evidenced by ammonia adsorption microcalorimetry. Mesoporous materials are more acidic than the microporous analogues and
the amount of strong acid sites increases with the silicon content.
Authors:S. Boutamine, Z. Hank, M. Meklati, and O. Benali-Baitich
The effect of pH on the percent extraction of vanadium(V), iron(II), cobalt(II), nickel(II), copper(II), molybdenum(VI), tungsten(VI) and uranium(VI) by -benzoinoxime in different solvents has been studied. The maximum recovery is not appreciably affected by the nature of the solvent, but occurs at different pH values for different metals. The pH corresponding to maximum extraction increases with increasing hydrolysis pK of the species in aqueous solution, and decreases with increasing stability constant of the complexes formed. Alpha-benzoinoxime allows the separation of these metal ions into three groups: V(V), Mo(VI) and W(VI) are extracted at pH=2, U(VI) at pH=5, Fe(II), Cu(II), Co(II) and Ni(II) at around pH=10.
Multielemental neutron activation analysis was used for the determination of Al, As, Au, Br, Ca, Cd, Co, Cr, Cu, Fe, La, Mn,
Mo, Sb, Se, W and Zn in African tea, and lady's fingers (Malvaceae Family), ginger (Zingiperaceae Family), canella bark (Laureceae
Family), black pepper (Piperaceae Family), cucumber seeds and vegetable marrow seeds (Cucurbitaceae Family), tomatos seed
(Solanaceae Family), safflower seeds (Compositae Family), jew's mallow seeds (Tiliaceae Family) and sesame (Pedaliaceae Family).
Trace elements determination was made to the analysis of destructive (using super pure nitric acid and adsorbing the metal-APDC
and metal-Dz complexes on activated charcoal) and nondestructive (dry seeds) samples. The method is simple, precise and sensitive
for the determination of microamounts of the elements (ppm to ppb).
Authors:Jogender Lalla, Purnima Hamrapurkar, and Santosh Sacket
Pharmacopoeia of India, Vol. 2, Government of India, Ministry of Health and Family Welfare, Controller of Publications, Delhi, 1996, pp. 356–357.
S.K. Roy, R. Pal
, Indian J. Pharm