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Bulk, polycrystalline (Co, Cu, Mg, Ni, Zn)O was synthesized using solid-state sintering. Micropillars were prepared and mechanically deformed along three crystallographic orientations: (001), (101), and (111). Pillars (001) and (111) cracked, while Pillar (101) remained intact. Pillars (001) and (101) exhibited activated slip systems, confirmed by a large stress drop, and the presence of slip bands, respectively. Schmid factor (SF) analysis was performed to examine the effect of grain orientations on dislocation activity and slip behavior. SF values range from 0 to 0.5, with non-zero values indicating potential for slip. Six slip systems exist in the (Co, Cu, Mg, Ni, Zn)O rock salt crystal structure: 1/2⟨110⟩11¯0. For the (001) orientation, four slip systems are potentially active (SF = 0.5). For the (101) orientation, there are four potentially active slip systems (SF = 0.25). For the (111) orientation, no potentially active slips systems exist (SF = 0). Dislocation structures, which were observed post-compression via transmission electron microscopy, demonstrated variations in size, number, and distribution across the pillar, depending on micropillar orientation. Entangled dislocations created misorientation in Pillar (001), which led to the possible formation of subgrains, while singular dislocations were observed in Pillar (101), and a lack of dislocations was observed in Pillar (111). Zener–Stroh type dislocation entanglement-mediated cracking is the proposed cause of the transgranular-type cracks in Pillar (001). The possible subgrain formation, or lack of formation, respectively, caused intergranular-type cracks to additionally form in Pillar (001), while Pillar (111) only exhibited transgranular-type brittle fracture. In combination, these findings highlight the importance of dislocation activity, without the need for elevated temperature, and grain orientation in controlling the mechanical deformation response in single-phase (Co, Cu, Mg, Ni, Zn)O.
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The dimensionality of the epistemic orientation survey and longitudinal measurement invariance for the short form of EOS (EOS-SF)
The dimensionality of the epistemic orientation survey (EOS) was examined across four occasions with item factor analysis (IFA). Because of an emphasis on the knowledge generation of epistemic orientation (EO), four factors were selected and built into a short form of EOS (EOS-SF) including knowledge generation, knowledge replication, epistemic nature of knowledge, and student ability. To track the stability of the factor structure for each factor of EOS-SF, longitudinal invariance models were conducted. Partial measurement invariance was obtained for each of the four factors of EOS-SF. This study provides an example of ongoing instrument development in the field of applied assessment research.
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- Award ID(s):
- 1812576
- PAR ID:
- 10507463
- Publisher / Repository:
- Frontiers
- Date Published:
- Journal Name:
- Frontiers in Education
- Volume:
- 8
- ISSN:
- 2504-284X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3389/feduc.2023.1239751
