<p class="ICCENormalText1stparagraph">This study examined the effects of online procedural scaffolds (in the form of generic question-stems with context-specific examples) and the timing of scaffolding provision (immediate versus delayed) on supporting the online student question-generation learning process in a science class. A total of 78 fifth-grade Taiwanese students participated in eight online question-generation sessions. An online learning system equipped with a customizable scaffolding design in terms of content and timing of access was used. The results of ANOVAs on the students' week-by-week question-generation performance showed the immediate positive effects of immediate procedural scaffolding. However, the delayed procedural scaffolds group did not statistically distinguish themselves from the no-scaffolds group in any of the eight question-generation performances, nor did the delayed approach engender productive failure, as postulated by some researchers. The significance of this study is discussed, along with suggestions for related instructional implementations, online systems and future research.</p><br />

The evolution of microstructure and mechanical properties of the Ni-25Al-27.5Fe-1.0Nb intermetallic alloy after thermal mechanical treatment (TMT) was systematically investigated by means of X-ray diffractometry (XRD), scanning electron microscopy (SEM) with electron dispersive spectrum (EDS) capability, and atmosphere-controlled tensile test at room temperature with different strain rate. The results of XRD reveals that a matrix of β' phase [(Ni, Fe) Al type ordered bcc structure] and a precipitated γ phase (Ni3Fe fcc solid solution) co-exist in this alloy after TMT. The dendritic microstructure of the as-cast alloy was eliminated after TMT process. In parallel, a refined and homogeneous distributed lath precipitates can be obtained after annealing at 820 for 4 hr. Additionally, this alloy presents a relative high strength as well as ductile mechanical behavior (UTS~1320 MPa and ε~8%, respectively) at room temperature in air. A 30% improvement in yield strength is suggested to be contributed by the refined microstructure from the TMT. Moreover, the tensile strength and ductility of this alloy exhibit insensitive response with respect to the loading strain rate at room temperature.