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- Author or Editor: R. Swami x
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Thermal analysis of iron(II) sulphate heptahydrate in air
III. Thermal decomposition of intermediate hydrates
Iron(II) sulphate hydrates (hexa- through mono-) have been prepared and their thermal decomposition behaviours have been studied in air by isothermal and dynamic thermal analysis methods. The results show that their behaviours are similar to that of the heptahydrate. The stepwise loss of water molecules is accompanied by oxidation. Under a restricted supply of oxygen, the anhydrous sulphate is oxidized directly to Fe2O(SO4)2 without the formation of Fe(OH)SO4. When free exchange with oxygen is allowed, Fe(OH)SO4 is formed, which in turn decomposes to Fe2O(SO4)2. The decomposition of Fe2(SO4)2 to iron(III) oxide and sulphur oxides appears to occur via two independent paths — one direct and other through iron(III) sulphate.
Abstract
The dissolution of UO2 in carbonate-bicarbonate solutions containing sodium hypochlorite as an oxidant has been investigated. The effect of temperature, sodium hypochlorite concentration and stirring speed was examined. In the temperature range of 303 to 318 K, the leaching reaction displayed linear kinetics. Apparent activation energy obtained from the differential approach was found to be 57 kJ mol–1. This relatively high activation energy value indicates a chemically controlled behavior of UO2 dissolution. The order of reaction with respect to sodium hypochlorite concentration was found to be unity.
Abstract
Several studies have suggested that mate selection strategies alter with age, but the mechanism of this shift in mate strategy is unclear. Two possibilities suggest themselves. The first is that attractiveness preferences themselves alter, compensating for the changing mate value of the observer. Alternatively, the preferences may remain constant with observer age, but an individual may compensate for changes in their own relative attractiveness by consciously targeting different regions of the “attractiveness spectrum” as their own mate value changes. To address this question, we asked 142 Caucasian subjects (aged 18–87 years) to rate 50 photographs of women varying in lower body shape (the waist-hip ratio, or WHR), and overall body mass (body mass index, or BMI). We found no effects of observer age on attractiveness preferences. This suggests that the criteria for attractiveness do not alter with changing observer age, and instead that it is the strategies employed using this information that may change.
