The present study investigated specific teacher factors that potentially influence teacher-child relationships with preschool-age children. One demographic questionnaire and three rating scales were used to survey 152 head teachers of 3-6-year-old children in community-based childcare and preschool centers in one midwestern state. There were 46 teachers who reported on their relationship with a child with a disability or concerning developmental delay. Positive correlations were found between teacher-child relationships and the teachers' educational backgrounds, self-reported teaching efficacy, and parent-teacher relationships. The parent-teacher relationship appeared to be the strongest teacher-related factor predicting the quality of teacher-child relationships. Compared to other teachers, the teachers of children with delays or disabilities reported comparable parent-teacher relationships and more positive teacher-child relationships, especially when more than one child with concerns was reportedly enrolled in the classroom. Teachers with children who had developmental delays reported lower teaching efficacy scores. The role of parent-teacher relationships is highlighted as a possible moderator when teachers feel less than capable or positive about individual children in their program.

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The instability and the localization process of unstable plastic flow during constant pressure bulging of superplastic Ti-6Al-4V sheets at 900°C are analyzed. A generalized stability criterion is developed by generalizing Hart's stability criterion [Acta Metall., 15 (1967) 351] in terms of strain and strain rate. According to the stability criterion, a new concept of the 'flow localization factor', which enables a quantitative description of the localization process of unstable plastic flow, is presented. A finite element model that simulates experiments on constant pressure bulging is applied to compute the flow localization factor at the fracture point. It is found that the localization process of unstable plastic flow during constant pressure bulging can be divided into three stages:(1) the developing period of initial localized flow, (2) the steady stage of strain concentration, and (3) the accelerating stage of strain concentration, which results in the final fracture.