Of the nearly 47percentt of adolescents who reported pica behaviors, most – 82percentt – craved ice, followed by starches (flour, cornstarch), powders (dust, vacuum powder, baby powder), soap (bar, laundry and powdered), paper (sheet paper, toilet paper, tissues), plastic/foam (pillow stuffing, sponges), baking soda, and a few other items.
The studied nc-Si−SiOx structures were produced by evaporation of Si monoxide (SiO) powder in vacuum and oblique deposition on Si wafer, and then the deposited silicon oxide (SiOx) films were annealed in the vacuum at 975 °C to grow nc-Si.
However, annealing Degussa P25 powder in vacuum resulted in a redistribution of Ti3+-lattice states and lattice oxygen vacancies.
Yet another variation is electron beam melting (EBM); here the laser apparatus is replaced by an electron gun, which focuses a powerful electrically charged beam onto the powder under vacuum conditions.
Annealing the as-milled powder under vacuum above 520°C resulted in the formation of crystalline Cr2O3 nanoparticles separated from each other in a salt matrix.
Moreover, thin films of In2S3 were prepared from In2S3 powder using vacuum evaporation with resistively heated graphite crucible [20].
In their study, the olivine powder was vacuum sintered at 1240 °C (Fo90Fa10: Mg1.8Fe0.2SiO4) and the diopside powder (an end-member of Ca-pyroxene: CaMgSi2O6) was sintered at 1260 °C.
For example, Li3VO4−δ was synthesized by annealing Li3VO4 powders in vacuum, and the introduction of oxygen vacancies lead to the enhanced initial coulombic efficiency, reversible capacity, and cycling stability [20].
The powders were vacuum-dried at 105 °C for 24 h before the test.
A critical result of the functional characterization of powder feeding under vacuum is a potential reaction capacity limitation at low vacuum pressures due to short particle residence time and narrow axial dispersion.
