INVESTIGATION OF REACTIONS OF SIMPLE MAGNESIA SPINELS WITH ALKALINE EARTH ORTHOSILICATES IN THE SOLID STATE *

The spinels MgO Al₂O₃, MgO Cr₂O₃., and MgO Fe₂O₃ and the orthosilicates 2MgO SiO₂, 2CaO SiO₂, 2SrO SiO₂, and 2BaO SiO₂ were synthesized by solid-state reaction of the component oxides or compounds yielding the oxides on ignition. Each of the spinels was tested at various temperatures with each orthosilicate in turn by placing a pellet of each in contact and also by intimately mixing the two. Petrographic microscopy and X-ray diffraction were employed in the identification of reaction products.     

IRON OXIDE IN ENAMEL GLASS AS DISSOLVED FROM THE METAL BASE*

The iron oxide content of an enamel glass was measured by the use of a predetermined curve representing iron oxide versus the index of refraction. It was found that the iron oxide content of the glass adjoining the interface between the enamel and the iron base rises sharply in the early stages of firing to a value close to the solubility limit of the glass after which it gradually falls to a constant value. The iron content at the surface remains low until that at the interface decreases, whereupon the surface concentration correspondingly increases. The cobalt additions resulted in a lower iron content in solution at the interface, but they increased the dendrite content of the glass. A decrease in the cobalt content resulted in an opposite effect. There was a direct relation between the amounts of cobalt and dendrites and the adherence. The effects of temperature and thickness of application are given, and the results are discussed.     

SOLUBILITY OF A ZIRCONIUM OXIDE OPACIFIER IN ENAMEL GLASSES*

The solubility of a zirconium oxide opacifier was determined by fusion in enamel glasses and then by heat-treating at enameling temperatures and noting the amount of crystallization. An increase in the alumina, zinc oxide, and calcium oxide content in the glasses caused a decided decrease in the solubility of the zirconium oxide opacifier. The fusion temperatures of the enamels were raised by solution of zirconium oxide.     

EFFECT OF COEFFICIENT OF EXPANSION OF GROUND- AND COVER-COAT ENAMELS ON THERMAL-SHOCK AND IMPACT RESISTANCE *

Four antimony cover-coat enamels, four fluoride cover-coat enamels, and four ground-coat enamels were formulated to give varying coefficients of expansion. The calculated values were 250, 275, 300, and 325 × 10^–7. The observed coefficients of expansion are included in the paper. The enamels were applied to standard 2-quart pudding pans and were tested for thermal shock and impact resistance using the standard methods of the Enameled Utensil Manufacturers’Council. The results show that thermal-shock resistance is controlled chiefly by the coefficient of expansion of the ground-coat and cover-coat enamels. The best results were obtained by using a cover-coat enamel with a low coefficient of expansion and a ground coat with a high coefficient of expansion. No conclusive evidence was found to indicate any effect of the coefficient of expansion of the ground- and cover-coat enamels on impact resistance. The solubility resistance and reflectance curves for the enamels are also included.     

Distinguishing between green building occupants’ reasoned and unplanned behaviours

Several frameworks incorporate social and psychological elements of environmentally significant behaviour, and most assume cognitive and deliberate decision-making. Household energy consumption behaviours, however, span a spectrum from reasoned and deliberate to unplanned and automatic. The aim of this paper is to advance knowledge of reasoned and unplanned behaviours in the context of pro-environmental action. Using results of a survey administered to occupants of an urban residential green building, this study explores five household consumption behaviours and tests the hypothesis that unplanned behaviours will be poorly predicted by a reasoned, values-based behavioural framework. Using path analyses, variables in a values-based framework are used to predict surveyed behaviours. Findings indicate that behaviours hypothesized to be unplanned were not well predicted by the values-based framework. The framework successfully predicted what was hypothesized to be a fully reasoned behaviour. Three potential reasons are discussed for the lack of prediction of some behaviours. A deeper understanding of how unplanned, automatic or habitual behaviours intervene in conservation intentions can help policy-makers and building designers better respond to influences of occupant behaviour on building performance.