Tomography of insulating biological and geological materials using focused ion beam (FIB) sectioning and low-kV BSE imaging

Tomography in a focused ion beam (FIB) scanning electron microscope (SEM) is a powerful method for the characterization of three-dimensional micro- and nanostructures. Although this technique can be routinely applied to conducting materials, FIB–SEM tomography of many insulators, including biological, geological and ceramic samples, is often more difficult because of charging effects that disturb the serial sectioning using the ion beam or the imaging using the electron beam. Here, we show that automatic tomography of biological and geological samples can be achieved by serial sectioning with a focused ion beam and block-face imaging using low-kV backscattered electrons. In addition, a new ion milling geometry is used that reduces the effects of intensity gradients that are inherent in conventional geometry used for FIB–SEM tomography.     

Calculation of Viscosity-Temperature Curves for Porcelain Enamels from the Flow-Button Test

A procedure was developed for relating the speed of flow of enamel on an inclined plate to the viscosity-temperature curve of the enamel. The results of the flow-button test are represented in three-dimensional flow diagrams. An equation was developed for the calculation of the viscosity-temperature curves of twelve types of enamels. The equation includes a constant Q , having a value of 2.565, for flow of enamel samples on a plate inclined at 45°. Application of this method as a control for enamel melts is demonstrated. The influence of overmelting and undermelting on the viscosity of the enamel at different temperatures was examined.     

How to optimize the design of a quantitative HREM experiment so as to attain the highest precision

Using parameter estimation theory, an expression is derived for the maximum precision with which the position of a single atom can be estimated from high resolution transmission electron microscopy images. This expression, being a complicated function of the object as well as of the microscope parameters and the electron dose, can be used to optimize the design of an HREM experiment so as to attain the highest precision.     

PLACES AND PARTICIPATION: COMPARING RESIDENT PARTICIPATION IN POST‐WWII NEIGHBORHOODS IN NORTHWEST,CENTRAL AND SOUTHERN EUROPE

ABSTRACT: The participation of residents in improving their neighborhood, and especially variations in participation between places, has been the topic of research in various articles published in the last few years. What is still missing in these studies is an international comparative perspective, since national differences might be expected to account for at least part of the variation in participation. This article, therefore, includes an analysis of national differences. We assess how much relevance these national differences have in comparison with the influence of individual and neighborhood characteristics. Using multivariate modeling procedures, we address the following questions: To what extent can differences in participation be ascribed to neighborhood level variations (share of unemployed, share of ethnic minorities, share of owner-occupied housing, average experience of problems, share of residents active in a social organization)? And to what extent do national context variables (democratic history, empowerment policy) account for these differences? The findings suggest that both neighborhood and national context variables have explanatory power. The article provides an important starting point for a closer study of the role of national level factors.     

THE IMPACT OF ETHNIC CONCENTRATION ON PREJUDICE: THE ROLE OF CULTURAL AND SOCIOECONOMIC DIFFERENCES AMONG ETHNIC NEIGHBORHOOD RESIDENTS

Many studies have examined the impact of the size of the neighborhood minority population on prejudicial attitudes of majority residents. However, few studies have investigated how residents of different ethnic origins evaluate different ethnic outgroups based on the shares of these particular ethnic outgroups in their neighborhood. Based on the belief congruency theory and social identity theory, we propose that the effect of outgroup size on outgroup attitudes depends on the socioeconomic and cultural differences between ethnic groups. Multilevel analyses of Dutch survey data gathered among Turkish, Moroccan, Surinamese, Antillean, and native Dutch residents indicate that for most groups outgroup attitudes are not influenced by the share of the particular outgroup in their neighborhood. For some ethnic groups, however, the size of a particular outgroup is associated with less positive attitudes toward that outgroup. Differences in the effect of outgroup size on outgroup attitudes only partly correspond with cultural differences and socioeconomic status differences.     

CIVIC ENGAGEMENT IN URBAN NEIGHBORHOODS: DOES THE NETWORK OF CIVIC ORGANIZATIONS INFLUENCE PARTICIPATION IN NEIGHBORHOOD PROJECTS?

ABSTRACT: This article aims to explain variations in the participation of civic organizations in neighborhood projects. In particular, we inquire into the impact of the social networks of more than 400 local civic organizations on their participation in neighborhood projects in two Dutch cities. Two strands of literature constitute the basis for our arguments. First, there is much research on the determinants of individual participation showing that tenure, social‐economic status, and being a member of the majority matter considerably. Second, network studies demonstrate that the structure and content of one's relationships substantially influences successive actions. Our expectations are based on both bodies of knowledge. We survey the civic organizations in eight neighborhoods and analyze the impact of their social networks using multinomial logistic regression models. The results show that the actual number of relations in the network and the density of the networks are positively associated with participation in neighborhood projects. Furthermore, we show that organizations with high proportions of ethnic minorities provide less support, despite their networks. Finally, organizations with many professionals working for them participate more if their networks are taken into consideration.