High purity silica reflective heat shield development

A hyperpure vitreous silica material is being developed for use as a reflective and ablative heat shield for planetary entry. Various purity grades and forms of raw materials were evaluated along with various processing methods. Slip casting of high purity grain was selected as the best processing method, resulting in a highly reflective material in the wavelength bands of interest (the visible and ultraviolet regions). The selected material was characterized with respect to optical, mechanical and physical properties using a limited number of specimens. The process has been scaled up to produce a one-half scale heat shield (18 in. dia.) (45.72 cm) for a Jupiter entry vehicle. This work is now being extended to improve the structural safety factor of the heat shield by making hyperpure silica material tougher through the addition of silica fibers

Richard Hertwig Untersuchungen über das nervensystem und die Sinnesorgane der Medusen

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The effect of an intervention to improve newly qualified teachers’ interpersonal style, students motivation and psychological need satisfaction in sport-based physical education

Recent developments in self-determination theory research in the educational setting (e.g., Reeve, Deci, & Ryan, 2004), suggest that teachers’ interpersonal style should be considered as consisting of three dimensions: autonomy-support, structure and interpersonal involvement. Based on this theoretical proposition, the purpose of the present study was to test the effects of a training program for three physical education newly qualified teachers on the aforementioned teachers’ overt behaviors and students’ psychological needs satisfaction, self-determined motivation and engagement in sport-based physical education. After a baseline period of four lessons, the teachers attended an informational session on adaptive student motivation and how to support it. The training program also included individualized guidance during the last four lessons of the cycle. Results revealed that from pre- to post-intervention: (1) teachers managed to improve their teaching style in terms of all three dimensions, and (2) students were receptive to these changes, as shown by increases in their reported need satisfaction, self-determined motivation and engagement in the class