PERCEPTIONS OF ENERGY PROBLEMS AND THE ADOPTION OF CONSERVATION PRACTICES IN EDMONTON AND CALGARY

The success of government efforts to stimulate energy conservation among the public ultimately depends on understanding patterns of energy consumption, perceptions of energy resources, and the adoption of conservation practices. These issues were addressed in a survey of residents of Edmonton and Calgary. Most respondents dismissed the seriousness of energy problems at the provincial level, although energy scarcity at the national and global scales was widely recognized. Conservation behaviour was characterized by a narrow range of adjustments perceived and adopted, attributable largely to patterns of resource perception and socio-economic factors.
La réussite des efforts gouvernementaux pour stimuler les conservations d'energie dépend, en dernière analyse, d' une compréhension des schémas de la consommation énergétique, desperceptions des resourcesénergétiques, et del'adoption d' habitudesconservatrices. On a interrogé les habitants d' Edmonton et de Calgary ace sujet. La plupart des réponses ignorent la gravité des problèmes d'énergie au niveau provincial, quoiqu'elles admettent la précarité des ressources énergétiques à l' échelle nationale et mondiale. L' attitude conservatrice se distingue plus particulikrèment à partir d' ajustements limités reliés géneralement aux schémas de perceptions énergétiques et aux facteurs socio-économiques.     

UVB RADIATION DISTRIBUTION IN CANADA DURING 1992 AND 1993

One of the steps leading to an assessment of the biological significance of ozone destruction is to determine the biologically effective ultraviolet radiation (UVB) distribution. The objective of this study is to describe and analyze broadband UVB radiation at 24 locations across Canada, during the period from July 1992 through December 1993. This is the first study of broadband UVB measurements involving such a large number of UVB measuring instruments. Quantitative characteristics and statistical analysis of the surface UVB radiation in Canada with respect to ozone amount, as well as cloudiness, are presented. The results indicate higher UVB irradiance in the second half of 1992, compared with the same period in 1993. Among all the locations, Toronto received the greatest dose of UVB radiation in 1993. Excluding Yellowknife, due to its northernmost location (larger zenith angles), Ste-Agathe, Quebec received the smallest dose. Unusually high UVB fluxes were found to occur in March 1993 over eastern Canada. A study of the correlation of UVB radiation with total ozone and cloud opacity was carried out for most of the locations. The results suggest that other meteorological parameters have a significant impact on the ultraviolet levels.     

THE JUDICIOUS SELECTION AND PRESERVATION OF TUFF AND TRAVERTINE BUILDING STONE IN ANCIENT ROME*

The Republican and early Imperial monuments of Rome are, for the most part, built of tuffs quarried from at least seven pyroclastic deposits erupted from nearby Monti Sabatini and Alban Hills volcanoes. Remarks by Vitruvius (2.7.1–5), field observations of the monuments, and petrographic and rock testing studies of samples from Roman quarries demonstrate that Roman builders developed a good knowledge of the diverse material properties of the tuffs over centuries of use and exposure. Measurements of compressive strength, specific gravity, water absorption and adsorption of water vapour confirm that the petrographic characteristics of each tuff lithology strongly influence its strength and durability. Early construction utilized weakly durable, soft or vitric tuffs such as Tufo del Palatino or Tufo Giallo della Via Tiberina that are susceptible to decay, as at Temple C (290 bc ) of the Largo Argentina Sacred Area. Late Republican structures, such as the Temple of Portunus (80–90 bc ), employed somewhat durable, vitric–lithic Tufo Lionato reinforced with travertine, a durable limestone quarried near Tivoli. Roman builders selected the material properties of the tuffs to advantage for specific structural elements within large public monuments of the first century bc and the first century ad , as at the tabernae of the Forum of Caesar (46 bc ), where an upper storey of lightweight Tufo Lionato is supported by robust, lithic–crystal Lapis Gabinus pillars and flat arches reinforced with travertine. The tuffs are not very durable building stones; Romans preserved them with protective stucco, and travertine and marble cladding. Their high water intake, coupled with direct exposure to rain, daily fluctuations in relative humidity and urban weathering at present makes them especially vulnerable to decay.     

FURTHER STUDIES IN THE COMPOSITIONAL VARIABILITY OF COLOURLESS ROMANO‐BRITISH VESSEL GLASS*

Previous studies of colourless Romano‐British vessel glasses have suggested that, regardless of vessel type, they show considerable compositional homogeneity. Intriguing differences in variability (as opposed to mean composition) have, however, also emerged. This paper reports on a compositional study of 243 vessels, that is larger and more carefully controlled than in previous studies of this kind. Unexpected compositional differences have been found both between and within the four vessel types studied. We discuss the implications of these results in the context of different models that have been proposed for glass‐making and glass‐working in the Roman world.