The determination of major and some minor constituents in lead zirconate-titanate compositions by x-ray fluorescence and atomic absorption spectrometry

An accurate X-ray fluorescence spectrometric method is described for the determination of lead, zirconium and titanium in lead zirconate-titanate ceramics. Careful matching of samples and standards by a borax fusion method resulted in a relative standard deviation of about 0.2% for the major constituents. The determination, after separation, of the unreacted oxide of lead by atomic absorption spectrometry, and of the unreacted oxides of zirconium and titanium by X-ray fluorescence spectrometry is also described. An X-ray fluorescence spectrometric method is proposed for the determination of dope elements (K, La, Sm, Yb) with internal standards (Ca, Ce, Cr, Ni respectively). The magnesium dope is determined by atomic-absorption spectrometry with standard addition

Two calculation procedures for the determination of composition and mass thickness of thin samples by x-ray spectrometry

Two procedures are described for calculating the composition and mass thickness of thin samples from measured x-ray intensities. One procedure is suitable for use with a programmable hand calculator but gives correct results only for very thin samples. The other procedure utilizes the NRLXRF program and produces correct results for thin and thick films

Comparisons of the resurrection grass, Eragrostis nindensis, with the related desiccation-sensitive species, E. curvula

Bibliography: leaves 100-133.Desiccation tolerance of the inner leaves of Eragrostis nindensis is compared with the desiccation sensitivity of the outer leaves, as well as those of the closely related species, E. curvula. Both E. nindensis and E. curvula dehydrate to a relative water content (RWC) ofless than 5% in two weeks. Photosynthetic activity in E. curvula is maintained down to 40% RWC, after which further drying results in a sudden irreversible breakdown of the photosynthetic system and its pigments

Gettin\u27 Some Age on Me: Social Organization of Older People in a Rural American Community

The social life of older rural Americans is made up of relationships formed through kinship, their neighborhoods, and the organizations to which they belong. These social institutions are shaped by the ways people use them, and therefore change through time. In this precedent-setting study, John van Willigen uses the concept of social network to investigate life-course changes in the relationships of older people within the context of community history. Gettin\u27 Some Age on Me grew out of a study of more than 130 older people in a rural Kentucky county. They were interviewed concerning their relationships with others, and data were collected on the give and take of support that is part of their social life. An understanding of community life and history, developed through interviews and period documentation, provided a context for understanding the changes these people have experienced over time. Finally, related studies by other researchers provided a framework for interpreting rural and urban differences. Van Willigen skillfully interweaves these various accounts to reveal fundamentally important patterns. It is clear that these other people should be viewed not as dependent and isolated but as important sources for social support; that even though their social relationships decline in number late in life, early in the post retirement period there is an apparent increase in social involvement; and that older people are much less isolated in the rural community studied than in many urban areas. This book makes a substantial contribution to the very limited literature on aging in rural America. It is important reading for social gerontologists and for all social scientists with an interest in American communities. John van Willigen is professor of anthropology at the University of Kentucky and the author of many books, including Tobacco Culture: Farming Kentucky\u27s Burley Belt and Food and Everyday Life on Kentucky Family Farms, 1920-1950. One of the standards in the study of social-network analysis. —American Journal of Sociology Well written and rich in empirical material. —American Anthropologisthttps://uknowledge.uky.edu/upk_gerontology/1004/thumbnail.jp

Zeldzame vissen in het IJsselmeergebied : jaarrapport 2002

In deze rapportage wordt een overzicht gegeven van de vangsten in de periode 1994 t/m 2002, waarbij voor de hele periode een selectie gemaakt is van de vissers die gedurende de laatste twee jaren de bemonstering uitgevoerd hebben. Van negen zeldzame soorten (waaronder vijf rode lijstsoorten) presenteren we verspreiding in de ruimte en tijd, lengtefrequentieverdelingen, rijpheidsstadia en geslachtsverhoudingen

The effect of nitrogen and the method of application on yield and quality of broccoli

The effects of the rate and the method of N application on yield and quality of broccoli cv. Emperor were studied during 3 seasons at Andijk and Lelystad, Netherlands. Different amounts of N fertilizer were applied broadcast or band placed at planting. Band placement of fertilizer increased the yield in 5 out of 8 experiments. Application of N resulted in larger heads. No relationship was found between soil mineral N at planting and optimum N application because of the narrow range of soil mineral N at planting. Split application had no or a negative effect on yield and therefore is not recommended. For optimum yields a rate of 270 kg N/ha is recommended, minus the mineral N in the 0-60 cm soil layer, band placed at planting. For broadcast application 275 kg N minus the soil mineral N is recommended at planting, but yields will be lower than with band placement of fertilizer